Impact of inferior vena cava thrombosis on the incidence of pulmonary embolism in patients with lower extremity deep vein thrombosis

Impact of inferior vena cava thrombosis on the incidence of pulmonary embolism in patients with lower extremity deep vein thrombosis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Impact of inferior vena cava thrombosis on the incidence of pulmonary embolism in patients with lower extremity deep vein thrombosis Yiman Zhang, Yan Meng, You Li, Mengyang Kang, Qiang Ma, Junbo Zhang, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4590808/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Jun, 2025 Read the published version in Scientific Reports → Version 1 posted 10 You are reading this latest preprint version Abstract Inferior vena cava thrombosis (IVCT) is a special form of venous thromboembolism. Lower extremity deep vein thrombosis (LEDVT) is associated with an increased incidence of pulmonary embolism (PE), but the association between concomitant IVCT and PE in patients with LEDVT has not been reported. We conducted a retrospective analysis of clinical data from patients confirmed with LEDVT at the First Affiliated Hospital of Xi’an Jiaotong University. Predictive variables of PE were selected using LASSO regression, and independent risk factors were identified through multivariable logistic regression. Of the 2929 patients, 40.9% had PE and 12.8% had IVCT. Multivariable logistic regression suggested that IVCT (OR 1.42, 95% CI 1.13–1.79) was an independent risk factor for PE. Subgroup analysis showed that IVCT was associated with increased odds of PE in patients with left LEDVT (OR 2.00, 95% CI 1.50–2.67), right LEDVT (OR 2.05, 95% CI 1.20–3.50), distal LEDVT (OR 5.15, 95% CI 1.31–20.22), and proximal LEDVT (OR 1.48, 95% CI 1.19–1.86). Concomitant IVCT significantly increased the incidence of PE in patients with LEDVT. There was no difference in PE severity or risk stratification between patients with and without IVCT. These finding could contribute to further improve the understanding of IVCT among clinicians, and optimize monitoring and management strategies of patients with LEDVT. Health sciences/Diseases/Cardiovascular diseases/Vascular diseases/Thromboembolism Health sciences/Diseases/Cardiovascular diseases/Vascular diseases/Thrombosis Health sciences/Risk factors Inferior vena cava thrombosis Pulmonary embolism Lower extremity deep vein thrombosis Risk factors Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Venous thromboembolism (VTE) is the third most common vascular disease after myocardial infarction and stroke, affecting nearly 10 million people worldwide each year and causing a huge global disease burden 1 . VTE comprises deep vein thrombosis (DVT) and pulmonary embolism (PE), both of which share the same predisposing factors. It is well known that PE usually occurs rapidly and has a high mortality. An international registry study showed that the 7-day all-cause mortality rate was 2.6% and the 30-day all-cause mortality rate was 5.9% for PE 2 . In Europe, PE accounted for 8–13 deaths per 1 000 women and 2–7 deaths per 1 000 men among people aged 15–55 years 3 . Studying the risk factors for PE and evaluating their potential impacts on PE is critical for preventing PE occurrence. Various risk factors for PE have been reported, including surgery, bone fractures, immobilisation, infection, cancer, autoimmune diseases, pregnancy, heritability, and family history 4 . Therefore, it is important to identify other relevant risk factors for PE. Emboli that cause PE can originate from the inferior vena cava pathway, superior vena cava pathway, or the right heart chamber. Pulmonary emboli most commonly arise from a lower extremity deep vein thrombosis (LEDVT) 5 . Inferior vena cava thrombosis (IVCT) is a special form of VTE associated with significant mortality 6 . However, IVCT remains under-recognized 7 , 8 . IVCT most commonly derives from proximal extension of an LEDVT, whereas isolated IVCT is rare and is usually associated with inferior vena cava outflow obstruction 9 . The incidence of IVCT is 4–15% in patients with confirmed DVT 8 , 9 . Previous studies have also found that 30% of untreated patients with IVCT will develop PE 6 . However, the association between concomitant IVCT and PE in patients with LEDVT has not yet been reported. This study aimed to investigate the effect of IVCT on the risk of PE in patients with LEDVT. A subgroup analysis was performed based on the location characteristics of LEDVT. Moreover, PE severity and risk stratification of early death were compared between patients with and without IVCT. Methods Patients and Study Design We retrospectively collected data from 3211 consecutive inpatients diagnosed with VTE at the First Affiliated Hospital of Xi'an Jiaotong University from June 2008 to June 2018. The inclusion criteria were as follows: 1) confirmed diagnosis of LEDVT, and 2) completion of CT angiography or angiography of the pulmonary artery and inferior vena cava (IVC). The exclusion criteria were as follows: 1) no LEDVT, 2) indwelling inferior vena cava filter before admission, 3) previous unhealed LEDVT, 4) age < 18 years, and 5) incomplete baseline information. This study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Review Committee of the First Affiliated Hospital of Xi'an Jiaotong University. Informed consent was waived by the Ethics Review Committee of the First Affiliated Hospital of Xi'an Jiaotong University due to the retrospective study design. Data Collection Clinical data such as age, sex, heart rate, blood pressure, comorbidities (chronic heart failure, paralytic stroke, autoimmune disease, and nephrotic syndrome), risk factors for VTE (malignant tumor, immobilization, fracture of lower limb, leg varicosities, pregnancy or postpartum, infection, blood transfusion, smoking), D-dimer value, the imaging information of LEDVT characteristics (LEDVT limb and LEDVT type), presence of IVCT, and presence of PE were collected from the electronic medical record system of the First Affiliated Hospital of Xi’an Jiaotong University. LEDVT was primarily diagnosed using Doppler ultrasonography, and venography or computed tomography (CT) venography was used for further clarification in cases in which Doppler ultrasonography was inconclusive. IVCT and PE required confirmation using either CT angiography or angiography of pulmonary artery and IVC. Plasma D-dimer levels were measured within 24 h of admission. Age-adjusted D-dimer (AADD) > 0.5 µg/mL was deemed abnormal for patients aged 50 years 10 . The Pulmonary Embolism Severity Index (PESI) class and risk stratification of early death in patients with PE were assessed based on the European Society of Cardiology guidelines for PE 11 . Statistical Analysis Continuous variables are presented as means ± standard deviations or medians (interquartile range, IQR) and were compared using independent samples Student’s t-test or the Mann-Whitney U test. Categorical variables were compared using the chi-squared test or Fisher’s exact test. Predictive variables were selected using LASSO regression, and independent risk factors were identified through multivariable logistic regression. Binary logistic regression was used to evaluate the effect of IVCT on the risk of PE in subgroup analysis. A two-sided P -value < 0.05 was considered statistically significant. Statistical analyses were performed using R software (version 4.2.1; R Development Core Team) and SPSS version 26.0 (IBM Corp., Armonk, NY, USA). Results A total of 3047 patients were diagnosed with LEDVT during the study period. After exclusion of 118 patients, 2929 patients with LEDVT were included in the analysis. The patient inclusion flowchart is summarized in Fig. 1. Baseline and clinical characteristics of patients Among 2929 LEDVT patients, 1198 (40.9%) patients with PE were categorized as the PE group, and 1731 (59.1%) patients without PE were categorized as the non-PE group. Table 1 compares the demographic and clinical characteristics of the patients in the two groups. The mean age of patients with PE was 59.2 ± 14.5 years, and the mean age of patients without PE was 55.4 ± 15.5 years. Patients with PE were older than patients without PE ( P < 0.001). Of the patients with PE, 49.7% were male, whereas 45.6% of patients without PE were male. The proportion of male patients with PE was higher than that of male patients without PE ( P = 0.035). The proportion of patients with heart rate >100 bpm in the PE group was higher than that in the non-PE group ( P < 0.001), but there was no difference in systolic blood pressure between patients with PE and patients without PE. Furthermore, patients with PE were more likely to have bilateral LEDVT (18.4% vs. 10.9%, P < 0.001), proximal LEDVT (88.1% vs. 82.6%, P < 0.001), chronic heart disease (7.2% vs. 2.4%, P < 0.001), nephrotic syndrome (2.8% vs. 1.3%, P = 0.008), or infection (9.9% vs. 4.6%, P < 0.001) than those without PE. No significant differences were observed for paralytic stroke, autoimmune disease, malignant tumour, immobilisation, lower limb fracture, leg varicosities, pregnancy or postpartum period, blood transfusion, or smoking. The D-dimer level was higher in patients with PE than that in patients without PE (median: 5.8 μg/mL vs. 3.6 μg/mL, P < 0.001). Similarly, the proportion of positive AADD results in patients with PE was higher than that in patients without PE (93.8% vs. 82.5%, P < 0.001). In addition, IVCT was noted in 12.8% (374/2929) of the patients. The proportion of IVCT in patients with PE was higher than that in patients without PE (16.0% vs. 10.5%, P < 0.001). IVCT as an independent risk factor for PE First, we used LASSO regression to select predictive variables associated with the occurrence of PE in patients with LEDVT. The variation characteristics of the coefficients of these variables are shown in Fig. 2a. The 10-fold cross-validation method was applied to the iterative analysis, and a model with excellent performance but a minimum number of variables was obtained when λ was 0.02025312 (Log (λ) = -3.899446) (Fig. 2b). After LASSO regression, eight risk factors were selected: age, LEDVT limb, IVCT, LEDVT type, infection, heart rate, chronic heart failure, and AADD (Fig. 2c). Independent risk factors were identified using multivariate logistic regression. The results showed that IVCT (OR 1.42; 95% CI 1.13-1.79, P = 0.003), age (OR 1.02; 95% CI 1.01-1.02, P < 0.001), right LEDVT (OR 1.21; 95% CI 1.01-1.45, P = 0.043), bilateral LEDVT (OR 1.87; 95% CI 1.49-2.35, P < 0.001), proximal LEDVT (OR 1.53; 95% CI 1.22-1.92, P < 0.001), chronic heart failure (OR 2.55; 95% CI 1.74-3.80, P < 0.001), infection (OR 2.00; 95% CI 1.48-2.73, P 100 bpm (OR 1.97; 95% CI 1.53-2.55, P < 0.001), or positive AADD (OR 3.00; 95% CI 2.29-3.97, P < 0.001) were independent risk factors for PE in patients with LEDVT (Fig. 3). Impact of IVCT on risk of PE in different subgroup By dividing the study population into subgroups based on LEDVT limb and LEDVT type, we further compared the risk of PE in patients with LEDVT with or without IVCT. The results showed that IVCT was associated with increased odds of PE in patients with left LEDVT (OR 2.00; 95% CI 1.50-2.67, P < 0.001), patients with right LEDVT (OR 2.05; 95% CI 1.20-3.50, P = 0.008), patients with distal LEDVT (OR 5.15; 95% CI 1.31-20.22, P = 0.019), and patients with proximal LEDVT (OR 1.48; 95% CI 1.19-1.86, P = 0.001). In contrast, IVCT was associated with decreased odds of PE in patients with bilateral LEDVT (OR 0.61; 95% CI 0.38-0.95, P = 0.030) (Table 2, Fig. 4). Association between PE severity, risk stratification, and IVCT The severity of PE was assessed using the PESI score. In classes Ⅰ, Ⅱ, Ⅲ, Ⅳ, and Ⅴ of PESI score, the proportions of patients with IVCT were 37.5%, 39.1%, 14.6%, 4.7%, and 4.2%, respectively, compared with 32.6%, 41.9%, 15.9%, 4.9%, and 4.7% of patients without IVCT, respectively. There were no statistically significant differences between the groups ( P = 0.780) (Table 3; Fig. 5a). We also assessed risk stratification for early death in patients with PE. The proportions of patients with IVCT at low, intermediate-low, intermediate-high, and high risk were 60.9%, 7.8%, 18.8%, and 12.5%, respectively. The proportions of patients without IVCT at low, intermediate-low, intermediate-high, and high risk were 58.9%, 11.2%, 17.2%, and 12.6%, respectively. There were no statistically significant differences between the groups ( P = 0.552) (Table 3; Fig. 5b). Discussion This retrospective observational study investigated the effect of IVCT on the incidence of PE in a cohort of patients with LEDVT. The incidence of PE was higher in patients with LEDVT with concomitant IVCT, and IVCT was an independent risk factor for the occurrence of PE. However, IVCT did not affect PE severity or risk stratification. In the present study, 12.8% of LEDVT cases were complicated by IVCT. As previously reported, the incidence of IVCT is 4–15% in patients with LEDVT 8 , 9 . Our results fall between the results of previous studies. Some previous studies on LEDVT showed that LEDVT can trigger an increased risk of IVCT with extension of the thrombus burden 6 , 12 . Our study included patients hospitalised with LEDVT, most of whom had proximal or extensive thrombosis. Thus, we obtained an incidence of IVCT at the high level of the range. Many studies have demonstrated that LEDVT is associated with an increased incidence of PE; however, the association between concomitant IVCT and PE in patients with LEDVT has not been well elucidated. A previous study showed that symptomatic PE was more frequently observed in patients with IVCT when compared with sex- and age-matched patients with LEDVT, but the difference was not significant (27% vs. 12%, P = 0.064) 13 . Another previous study also showed that patients with IVCT had a higher PE risk than patients without IVCT, but the difference was also not statistically significant (62.5% vs. 54.2%, P = 0.329) 14 . These results may be influenced by the small sample size of the studies and the presence of some confounding variables. In the present study, the incidence of PE was significantly higher in patients with LEDVT with concomitant IVCT than in patients with LEDVT alone (51.3 vs. 39.4%, P < 0.001), and multivariate logistic regression showed that IVCT is one of the independent risk factors for PE in patients with LEDVT (OR, 1.42; 95%CI, 1.13–1.79, P = 0.003). The probability of PE is known to be higher in patients with proximal LEDVT than in patients with distal LEDVT 15 , 16 . Similarly, our study showed that patients with proximal LEDVT had a higher risk of PE than those with distal LEDVT, which is consistent with the results of previous studies 17 , 18 . The above evidence suggests that the location of the thrombus is associated with PE risk, which may be related to different clot burden and embolic potential. IVCT is located in the inferior vena cava and is closer to the lungs. It may have a larger clot burden or higher embolic potential than LEDVT. Hence, LEDVT combined with IVCT is more likely to result in PE than LEDVT alone. Regarding the association between the LEDVT limb and PE, our study found that the risk of PE was in the order bilateral LEDVT > right LEDVT > left LEDVT. Li et al. and Shi et al. reported that patients with right LEDVT have a higher risk of PE than those with left LEDVT 19 , 20 . This phenomenon may be due to anatomical factors such as frequent compression of the left common iliac vein, which may lead to DVT, but at the same time may prevent thrombi from escaping from the lower extremity veins to lungs 19 – 21 . A study by Zhang et al. also drew the same conclusion. They provided a different explanation, suggesting that it may be related to more comorbidities in patients with right LEDVT 22 . However, the proportion of comorbidities did not differ between the right and left LEDVT groups in our study. Therefore, we believe that their explanation requires further exploration. Previous DVT studies have paid little attention to bilateral LEDVT. A previous retrospective case-control study showed that patients with bilateral LEDVT exhibited a 2.4-fold higher risk of PE than those with unilateral LEDVT 23 . In the present study, we subdivided patients with unilateral LEDVT into left and right LEDVT and obtained consistent results. We believe that patients with bilateral LEDVT tend to have greater thrombotic extent and heavier thrombus burden, resulting in a higher risk of PE. In addition, we found that age, chronic heart failure, infection, heart rate > 100 bpm, and positive AADD results were independent risk factors for PE in patients with LEDVT. Of these, age, heart failure, infection, and AADD are widely recognised risk factors for VTE 2 , 24 . However, the association between these factors and PE in patients with LEDVT has not yet been elucidated. Therefore, further studies are warranted. A heart rate > 100 bpm is one of the items of the Wells score. The Wells score has been used to distinguish patients with suspected PE from those with DVT, and our study confirmed its predictive role for PE. To further clarify the relationship between concomitant IVCT and PE at different LEDVT sites, the study population was divided into subgroups. The results showed that in the left, right, proximal, and distal LEDVT subgroups, the risk of PE was higher in patients with IVCT than in those without IVCT. Unexpectedly, however, these results were reversed in patients with bilateral LEDVT. IVCT has been reported to result in fatal PE; the patient in the report died on the way to the emergency room 25 . Furthermore, the mortality rate of IVCT is 2-fold higher than that of LEDVT alone 7 . In view of the above, we speculate that some patients with bilateral LEDVT and concomitant IVCT who have a very heavy thrombus burden may have fatal or severe PE, leading to death before admission or abandonment of treatment in the emergency department. This subset of patients could not be included in the present study; thus, the risk of PE is underestimated in patients with bilateral LEDVT and IVCT. We believe that the risk of PE is higher in patients with bilateral LEDVT and IVCT than in those without IVCT. Further studies are required to clarify this issue. Interestingly, patients with distal LEDVT and IVCT had a 5-fold higher risk of PE than those without IVCT. The increased risk in distal LEDVT was higher than that in proximal LEDVT. Therefore, clinicians should pay more attention to patients with distal LEDVT to identify the potential risk of IVCT and prevent the occurrence of PE. In the present study, we evaluated the association between IVCT and PE severity and risk stratification. The PESI class and risk stratification for PE represent the risk of death within the first 30 days 11 . There was no difference in the severity and risk stratification of PE between patients with and without IVCT. This result may be associated with active and adequate therapy for all hospitalised patients. Although a previous study suggested that IVCT was a risk factor for silent PE 26 , it is known that the presence or absence of symptoms of PE does not fully reflect the severity. Currently, few studies have investigated the prognosis of patients with LEDVT and concomitant IVCT. Previously, a prospective observational study compared the outcomes of IVCT and LEDVT and concluded that the 24-month all-cause mortality rate was higher in patients with IVCT than in those with LEDVT 27 . However, in-hospital and short-term outcomes were not reported. The present study has several limitations. First, this was a single-centre retrospective cohort study, and selection bias may have been unavoidable. Second, some risk factors for VTE, such as thrombophilia, hormone replacement therapy, and oral contraceptive use, were not analysed in this study because of the inability to obtain accurate information. Third, we did not consider medication use. Some patients used anticoagulants before admission, which may have influenced the D-dimer levels and prevented thrombus extension and subsequent PE. Fourth, we lacked data on the time from LEDVT diagnosis to the occurrence of PE and the time from LEDVT diagnosis to the appearance of IVCT, so we did not evaluate the association between IVCT and PE occurrence longitudinally. Despite these limitations, to our knowledge, our study is the first to investigate the effect of concomitant IVCT on PE in patients with LEDVT. Large-scale prospective multicentre studies are needed to verify these results. In conclusion, concomitant IVCT was associated with a significantly increased risk for PE compared with no IVCT among patients with LEDVT, and was an independent risk factor for PE. However, IVCT did not affect PE severity or risk stratification. Our finding could contribute to further improve the understanding of IVCT among clinicians, and suggest that, when managing patients with LEDVT, it is important to focus on identifying IVCT and adjust the monitoring and management strategies based on the presence or absence of IVCT. Declarations Acknowledgements We thank to Xinye Yao and Bowen Fu (Xi’an Jiaotong University) for the data collection. We also thank Nurse Manager Zhou Hongyan (Department of Peripheral Vascular Diseases, The First Affiliated Hospital of Xi’an Jiaotong University) for patient care. Author contributions Y.Z., Q.Y. and H.T. designed the study. Y.M., Y.L. and M.K. collected the data. Y.Z., Q.M., J.Z. and Q.Y. analysed and interpreted the data. Y.Z. drafted the manuscript. Y.M., Y.L., M.K., Q.M., J.Z., J.Y., H.T. and Q.Y. revised the manuscript. All authors have read and approved this manuscript for submission. Additional information Competing interests The authors declare no competing interests. Finding This study was supported by the Key Industry Innovation Chain Project of Shaanxi province, China (No. 2022ZDLSF02-02) and the Clinical Research Award of The First Affiliated Hospital of Xi’an Jiaotong University, China (No. XJTU1AF-CRF-2018-021). Data Availability Our data is available from the corresponding authors on reasonable request. References Khan, F., Tritschler, T., Kahn, S. R., Rodger, M. A. Venous thromboembolism. Lancet. 398, 64–77 (2021). Jiménez, D. et al. Trends in the Management and Outcomes of Acute Pulmonary Embolism: Analysis From the RIETE Registry. J Am Coll Cardiol. 67, 162–70 (2016). Barco, S. et al. Trends in mortality related to pulmonary embolism in the European Region, 2000-15: analysis of vital registration data from the WHO Mortality Database. Lancet Respir Med. 8, 277–87 (2020). Lutsey, P. L., Zakai, N. A. Epidemiology and prevention of venous thromboembolism. Nat Rev Cardiol. 20, 248–62 (2023). Kahn, S. R., de Wit, K. Pulmonary Embolism. N Engl J Med. 387, 45–57 (2022). Alkhouli, M., Morad, M., Narins, C. R., Raza, F., Bashir, R. Inferior Vena Cava Thrombosis. JACC Cardiovasc Interv. 9, 629–43 (2016). Lin, H. Y., Lin, C. Y., Shen, M. C. Review article inferior vena cava thrombosis: a case series of patients observed in Taiwan and literature review. Thromb J. 19, 43 (2021). McAree, B. J. et al. Inferior vena cava thrombosis: a review of current practice. Vasc Med. 18, 32–43 (2013). Shi, W., Dowell, J. D. Etiology and treatment of acute inferior vena cava thrombosis. Thromb Res. 149, 9–16 (2017). Kakkos, S. K. et al. Editor's Choice - European Society for Vascular Surgery (ESVS) 2021 Clinical Practice Guidelines on the Management of Venous Thrombosis. Eur J Vasc Endovasc Surg. 61, 9–82 (2021). Konstantinides, S. V. et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS). Eur Heart J. 41, 543–603 (2020). Avgerinos, E. D. et al. Impact of inferior vena cava thrombus extension on thrombolysis for acute iliofemoral thrombosis. J Vasc Surg Venous Lymphat Disord. 4, 385–91 (2016). Kraft, C. et al. Patients with inferior vena cava thrombosis frequently present with lower back pain and bilateral lower-extremity deep vein thrombosis. Vasa. 42, 275–83 (2013). Gong, M. et al. Risk factors and a predictive model for nonfilter-associated inferior vena cava thrombosis in patients with lower extremity deep vein thrombosis. Front Cardiovasc Med. 9, 1083152 (2022). Yamaki, T. et al. Factors predicting development of post-thrombotic syndrome in patients with a first episode of deep vein thrombosis: preliminary report. Eur J Vasc Endovasc Surg. 41, 126–33 (2011). Konstantinides, S. V. et al. 2014 ESC guidelines on the diagnosis and management of acute pulmonary embolism. Eur Heart J. 35, 3033–69, 69a-69k (2014). Boc, A., Vene, N., Stalc, M., Košmelj, K., Mavri, A. Unprovoked proximal venous thrombosis is associated with an increased risk of asymptomatic pulmonary embolism. Thromb Res. 133, 1011–5 (2014). Kucher, N., Tapson, V. F., Goldhaber, S. Z. Risk factors associated with symptomatic pulmonary embolism in a large cohort of deep vein thrombosis patients. Thromb Haemost. 93, 494–8 (2005). Li, F. et al. Risk factors associated with the occurrence of silent pulmonary embolism in patients with deep venous thrombosis of the lower limb. Phlebology. 29, 442–6 (2014). Shi, Y. et al. Impact of Common Iliac Vein Compression on the Incidence of Pulmonary Embolism in Patients with Acute Deep Vein Thrombosis. Eur J Vasc Endovasc Surg. 65, 887–94 (2023). Chen, F., Huang, J. G., Liu, X., Zhou, W. Left iliac vein involvement is a protective factor against symptomatic pulmonary embolism in lower left extremity deep vein thrombosis. J Vasc Surg Venous Lymphat Disord. 10, 1272–78 (2022). Zhang, C. et al. Relationship between the site of thrombosis and the prevalence of pulmonary embolism in acute lower extremity deep venous thrombosis. J Vasc Surg Venous Lymphat Disord. 8, 725–33 (2020). Zhang, J. et al. Anatomic distribution of lower extremity deep venous thrombosis is associated with an increased risk of pulmonary embolism: A 10-year retrospective analysis. Front Cardiovasc Med. 10, 1154875 (2023). Freund, Y., Cohen-Aubart, F., Bloom, B. Acute Pulmonary Embolism: A Review. JAMA. 328, 1336–45 (2022). Hanterdsith, B. Fatal Pulmonary Thromboembolism due to Inferior Vena Cava Thrombosis. Ann Vasc Dis. 4, 121–3 (2011). Shi, Y. et al. Silent Pulmonary Embolism in Deep Vein Thrombosis: Relationship and Risk Factors. Clin Appl Thromb Hemost. 28, 10760296221131034 (2022). Cohen, O. et al. Management strategies and clinical outcomes in patients with inferior vena cava thrombosis: Data from GARFIELD-VTE. J Thromb Haemost. 20, 366–74 (2022). Tables Table 1. Baseline and clinical characteristics of patients with and without PE Variables Total (n=2929) PE (n=1198) No PE (n=1731) P value Age - years 57.0 ± 15.2 59.2 ± 14.5 55.4 ± 15.5 < 0.001 Male 1385 (47.3%) 595 (49.7%) 790 (45.6%) 0.035 Heart rate - bpm 100 296 (10.1%) 174 (14.5%) 122 (7.1%) SBP - mmHg 124.0 ± 18.1 125.0 ± 17.9 124.0 ± 18.2 0.145 LEDVT limb < 0.001 Left limb 1776 (60.6%) 677 (56.5%) 1099 (63.5%) Right limb 745 (25.4%) 301 (25.1%) 444 (25.6%) Bilateral limbs 408 (13.9%) 220 (18.4%) 188 (10.9%) LEDVT type < 0.001 Proximal 2486 (84.9%) 1056 (88.1%) 1430 (82.6%) Distal 443 (15.1%) 142 (11.9%) 301 (17.4%) Comorbidities Chronic heart failure 128 (4.4%) 86 (7.2%) 42 (2.4%) < 0.001 Paralytic stroke 136 (4.6%) 54 (4.5%) 82 (4.7%) 0.841 Autoimmune disease 143 (4.9%) 55 (4.6%) 88 (5.1%) 0.602 Nephrotic syndrome 56 (1.91%) 33 (2.8%) 23 (1.3%) 0.008 Risk factors Malignant tumor 379 (12.9%) 161 (13.4%) 218 (12.6%) 0.539 Immobilization 813 (27.8%) 311 (26.0%) 502 (29.0%) 0.078 Fracture of lower limb 261 (8.9%) 117 (9.8%) 144 (8.3%) 0.199 Leg varicosities 161 (5.5%) 59 (4.9%) 102 (5.9%) 0.295 Pregnancy/postpartum 120 (4.1%) 39 (3.3%) 81 (4.7%) 0.058 Infection 199 (6.8%) 119 (9.9%) 80 (4.6%) < 0.001 Blood transfusion 123 (4.2%) 52 (4.34%) 71 (4.10%) 0.823 Smoking 739 (25.2%) 322 (26.9%) 417 (24.1%) 0.096 D-dimer - μg/mL 4.4 (1.7-9.9) 5.8 (2.6-11.7) 3.6 (1.1-8.6) < 0.001 AADD positive 2552 (87.1%) 1124 (93.8%) 1428 (82.5%) < 0.001 IVCT 374 (12.8%) 192 (16.0%) 182 (10.5%) < 0.001 Data are presented as mean ± standard deviation, n (%), or median (interquartile range). PE, pulmonary embolism; SBP, systolic blood pressure; LEDVT, lower extremity deep vein thrombosis; AADD, age-adjusted D-dimer; IVCT, inferior vena cava thrombosis Table 2. Subgroup analysis for the association between PE and IVCT Variables IVCT (n=374) Non-IVCT (n=2 555) OR (95% CI) P value LEDVT limb Left 114 (53.0%) 563 (36.1%) 2.00 (1.50-2.67) < 0.001 Right 34 (56.7%) 267 (39.0%) 2.05 (1.20-3.50) 0.008 Bilateral 44 (44.4%) 176 (57.0%) 0.61 (0.38-0.95) 0.030 LEDVT type Distal 7 (70.0%) 135 (31.2%) 5.15 (1.31-20.22) 0.019 Proximal 185 (50.8%) 871 (41.0%) 1.48 (1.19-1.86) 0.001 Binary logistic regression was performed to obtain the OR with a 95% CI of PE. PE, pulmonary embolism; IVCT, inferior vena cava thrombosis; LEDVT, lower extremity deep vein thrombosis; OR, odds ratio; CI, confidence interval Table 3. Comparison of PESI class and risk stratification of PE between patients with and without IVCT Variables IVCT (n=192) Non-IVCT (n=1 006) P value PESI score 0.780 Class Ⅰ 72 (37.5%) 328 (32.6%) Class Ⅱ 75 (39.1%) 422 (41.9%) Class Ⅲ 28 (14.6%) 160 (15.9%) Class Ⅳ 9 (4.7%) 49 (4.9%) Class Ⅴ 8 (4.2%) 47 (4.7%) Risk stratification 0.552 Low 117 (60.9%) 593 (58.9%) Intermediate-low 15 (7.8%) 113 (11.2%) Intermediate-high 36 (18.8%) 173 (17.2%) High 24 (12.5%) 127 (12.6%) PESI, Pulmonary Embolism Severity Index; IVCT, inferior vena cava thrombosis Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 05 Jun, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 28 Jan, 2025 Reviews received at journal 26 Jan, 2025 Reviewers agreed at journal 13 Jan, 2025 Reviews received at journal 09 Sep, 2024 Reviewers agreed at journal 26 Aug, 2024 Reviewers invited by journal 30 Jun, 2024 Editor assigned by journal 30 Jun, 2024 Editor invited by journal 19 Jun, 2024 Submission checks completed at journal 19 Jun, 2024 First submitted to journal 16 Jun, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4590808","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":322839426,"identity":"f9ba9cd2-b443-4ab7-bf87-e494f783e1f0","order_by":0,"name":"Yiman Zhang","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Yiman","middleName":"","lastName":"Zhang","suffix":""},{"id":322839427,"identity":"8cf140d1-b168-478d-98bb-08b7b01c4480","order_by":1,"name":"Yan Meng","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Yan","middleName":"","lastName":"Meng","suffix":""},{"id":322839428,"identity":"36f96feb-5375-44e8-8892-46c6b65393ed","order_by":2,"name":"You Li","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"You","middleName":"","lastName":"Li","suffix":""},{"id":322839429,"identity":"811f62c6-7619-43d5-9e1f-aa228eb90f71","order_by":3,"name":"Mengyang Kang","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Mengyang","middleName":"","lastName":"Kang","suffix":""},{"id":322839430,"identity":"83f3adb7-a385-4b4f-bdc9-1d4f3f3368ef","order_by":4,"name":"Qiang Ma","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Qiang","middleName":"","lastName":"Ma","suffix":""},{"id":322839431,"identity":"93a74fd3-52da-4953-989c-cdfe34bb4c39","order_by":5,"name":"Junbo Zhang","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Junbo","middleName":"","lastName":"Zhang","suffix":""},{"id":322839432,"identity":"73b2d298-061b-451a-8a8a-9a4984fd3dd3","order_by":6,"name":"Jian Yang","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Jian","middleName":"","lastName":"Yang","suffix":""},{"id":322839433,"identity":"f2e96238-b82e-4845-8a18-f1e761c822fa","order_by":7,"name":"Hongyan Tian","email":"","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Hongyan","middleName":"","lastName":"Tian","suffix":""},{"id":322839434,"identity":"601907d4-3c01-4ba0-934d-e194677918c6","order_by":8,"name":"Qian Yin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYDACZiBOYGCQY2NmPsAgARZKIE6LMR97WwKDRAIxWqAgUY7njAFUNQEtBsd5D954UHMngU0i55uE5Y/DDPzsOQYMP3fg0XKYL9ki4dizPDaJ3M0GEgmHGSR73hgw9p7Bp4XHTCKB7XAxUMvGByAtBjdyDJgZ2whp+Xc4sU0i58EBkBZ7orQktgG18JxhhNgiQUCL5GEeY4vEvsPGbOxtxgYSaek8EmeeFRzsxaOF7/wZw5s/vh2Wk29mfiYtYWMtx9+evPHBTzxaFA4wQOMcCJiBLB4Q4wBuDQwM8g1IWhg/4FM6CkbBKBgFIxYAAKE5TqWAoZWIAAAAAElFTkSuQmCC","orcid":"","institution":"The First Affiliated Hospital of Xi’an Jiaotong University","correspondingAuthor":true,"prefix":"","firstName":"Qian","middleName":"","lastName":"Yin","suffix":""}],"badges":[],"createdAt":"2024-06-16 19:53:18","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4590808/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4590808/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-04377-7","type":"published","date":"2025-06-05T15:56:53+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":60594594,"identity":"e47608c9-681e-4de7-b8d4-4d8e051d0484","added_by":"auto","created_at":"2024-07-18 15:22:24","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":299140,"visible":true,"origin":"","legend":"\u003cp\u003eStudy population flowchart. VTE, venous thromboembolism; LEDVT, lower extremity deep vein thrombosis; PE, pulmonary embolism; IVC, inferior vena cava; IVCT, inferior vena cava thrombosis.\u003c/p\u003e","description":"","filename":"OnlineFigure1.png","url":"https://assets-eu.researchsquare.com/files/rs-4590808/v1/b0ee45cda6b81884d26bd865.png"},{"id":60594599,"identity":"3a0d8dc7-2348-4725-9a74-0c6198b9215c","added_by":"auto","created_at":"2024-07-18 15:22:24","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":76943,"visible":true,"origin":"","legend":"\u003cp\u003ePredictive variables selection associated with occurrence of PE using LASSO regression. (a) LASSO coefficient profiles of the 20 variables. A coefficient profile plot was produced against the log (λ) sequence. (b) The process of selecting the optimal value of parameter λ in LASSO using the 10-fold cross-validation method. The value between the two dotted vertical lines is the range of standard deviations of log(λ). The right dotted vertical line indicates the least number of variables required when the cross-validation error is minimized. Eight variables were selected when λ was 0.02025312 (Log (λ) = -3.899446). (c) Bar chart of 8 important variables based on coefficients. PE, pulmonary embolism; LEDVT, lower extremity deep vein thrombosis; IVCT, inferior vena cava thrombosis; AADD, age-adjusted D-dimer.\u003c/p\u003e","description":"","filename":"OnlineFigure2.png","url":"https://assets-eu.researchsquare.com/files/rs-4590808/v1/7849d862c48b5d1627dff6e1.png"},{"id":60594596,"identity":"c7158601-79b7-4198-bb97-77300aa8984a","added_by":"auto","created_at":"2024-07-18 15:22:24","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":323518,"visible":true,"origin":"","legend":"\u003cp\u003eMultivariate logistic regression analysis of risk factors for PE in patients with LEDVT. PE, pulmonary embolism; LEDVT, lower extremity deep vein thrombosis; OR, odds ratio; CI, confidence interval; IVCT, inferior vena cava thrombosis; AADD, age-adjusted D-dimer.\u003c/p\u003e","description":"","filename":"OnlineFigure3.png","url":"https://assets-eu.researchsquare.com/files/rs-4590808/v1/56799d447bc20914246ac5e9.png"},{"id":60594595,"identity":"b9d1e6db-2023-4bfe-b050-4ba13ba8ef98","added_by":"auto","created_at":"2024-07-18 15:22:24","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":44349,"visible":true,"origin":"","legend":"\u003cp\u003eIncidence of PE between patients with and without IVCT by LEDVT limb (a) and LEDVT type (b). PE, pulmonary embolism; IVCT, inferior vena cava thrombosis; LEDVT, lower extremity deep vein thrombosis.\u003c/p\u003e","description":"","filename":"OnlineFigure4.png","url":"https://assets-eu.researchsquare.com/files/rs-4590808/v1/beb9b51ef0333bf267584fef.png"},{"id":60594598,"identity":"2e25741f-d3ed-4457-bdd0-8e1fb6d0736c","added_by":"auto","created_at":"2024-07-18 15:22:24","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":40388,"visible":true,"origin":"","legend":"\u003cp\u003ePESI class (a) and risk stratification (b) of PE between patients with and without IVCT. PESI, Pulmonary Embolism Severity Index; PE, pulmonary embolism; IVCT, inferior vena cava thrombosis.\u003c/p\u003e","description":"","filename":"OnlineFigure5.png","url":"https://assets-eu.researchsquare.com/files/rs-4590808/v1/17766c333d4c510575fa43c1.png"},{"id":84242665,"identity":"8168b789-094d-4a62-8d6a-c42f6cd72c9c","added_by":"auto","created_at":"2025-06-09 16:11:05","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2087648,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4590808/v1/eac0ceff-34a5-45ea-9f00-e199391be876.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of inferior vena cava thrombosis on the incidence of pulmonary embolism in patients with lower extremity deep vein thrombosis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eVenous thromboembolism (VTE) is the third most common vascular disease after myocardial infarction and stroke, affecting nearly 10\u0026nbsp;million people worldwide each year and causing a huge global disease burden\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. VTE comprises deep vein thrombosis (DVT) and pulmonary embolism (PE), both of which share the same predisposing factors. It is well known that PE usually occurs rapidly and has a high mortality. An international registry study showed that the 7-day all-cause mortality rate was 2.6% and the 30-day all-cause mortality rate was 5.9% for PE\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. In Europe, PE accounted for 8\u0026ndash;13 deaths per 1 000 women and 2\u0026ndash;7 deaths per 1 000 men among people aged 15\u0026ndash;55 years\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Studying the risk factors for PE and evaluating their potential impacts on PE is critical for preventing PE occurrence. Various risk factors for PE have been reported, including surgery, bone fractures, immobilisation, infection, cancer, autoimmune diseases, pregnancy, heritability, and family history\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Therefore, it is important to identify other relevant risk factors for PE.\u003c/p\u003e \u003cp\u003eEmboli that cause PE can originate from the inferior vena cava pathway, superior vena cava pathway, or the right heart chamber. Pulmonary emboli most commonly arise from a lower extremity deep vein thrombosis (LEDVT) \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Inferior vena cava thrombosis (IVCT) is a special form of VTE associated with significant mortality\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. However, IVCT remains under-recognized\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. IVCT most commonly derives from proximal extension of an LEDVT, whereas isolated IVCT is rare and is usually associated with inferior vena cava outflow obstruction\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. The incidence of IVCT is 4\u0026ndash;15% in patients with confirmed DVT\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Previous studies have also found that 30% of untreated patients with IVCT will develop PE\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. However, the association between concomitant IVCT and PE in patients with LEDVT has not yet been reported.\u003c/p\u003e \u003cp\u003eThis study aimed to investigate the effect of IVCT on the risk of PE in patients with LEDVT. A subgroup analysis was performed based on the location characteristics of LEDVT. Moreover, PE severity and risk stratification of early death were compared between patients with and without IVCT.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients and Study Design\u003c/h2\u003e \u003cp\u003eWe retrospectively collected data from 3211 consecutive inpatients diagnosed with VTE at the First Affiliated Hospital of Xi'an Jiaotong University from June 2008 to June 2018. The inclusion criteria were as follows: 1) confirmed diagnosis of LEDVT, and 2) completion of CT angiography or angiography of the pulmonary artery and inferior vena cava (IVC). The exclusion criteria were as follows: 1) no LEDVT, 2) indwelling inferior vena cava filter before admission, 3) previous unhealed LEDVT, 4) age\u0026thinsp;\u0026lt;\u0026thinsp;18 years, and 5) incomplete baseline information. This study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Review Committee of the First Affiliated Hospital of Xi'an Jiaotong University. Informed consent was waived by the Ethics Review Committee of the First Affiliated Hospital of Xi'an Jiaotong University due to the retrospective study design.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eData Collection\u003c/h2\u003e \u003cp\u003eClinical data such as age, sex, heart rate, blood pressure, comorbidities (chronic heart failure, paralytic stroke, autoimmune disease, and nephrotic syndrome), risk factors for VTE (malignant tumor, immobilization, fracture of lower limb, leg varicosities, pregnancy or postpartum, infection, blood transfusion, smoking), D-dimer value, the imaging information of LEDVT characteristics (LEDVT limb and LEDVT type), presence of IVCT, and presence of PE were collected from the electronic medical record system of the First Affiliated Hospital of Xi\u0026rsquo;an Jiaotong University.\u003c/p\u003e \u003cp\u003eLEDVT was primarily diagnosed using Doppler ultrasonography, and venography or computed tomography (CT) venography was used for further clarification in cases in which Doppler ultrasonography was inconclusive. IVCT and PE required confirmation using either CT angiography or angiography of pulmonary artery and IVC. Plasma D-dimer levels were measured within 24 h of admission. Age-adjusted D-dimer (AADD)\u0026thinsp;\u0026gt;\u0026thinsp;0.5 \u0026micro;g/mL was deemed abnormal for patients aged\u0026thinsp;\u0026lt;\u0026thinsp;50 years, and an age-adjusted threshold (age \u0026times; 0.01 \u0026micro;g/ml) was used for patients aged\u0026thinsp;\u0026gt;\u0026thinsp;50 years\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. The Pulmonary Embolism Severity Index (PESI) class and risk stratification of early death in patients with PE were assessed based on the European Society of Cardiology guidelines for PE\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eContinuous variables are presented as means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviations or medians (interquartile range, IQR) and were compared using independent samples Student\u0026rsquo;s t-test or the Mann-Whitney U test. Categorical variables were compared using the chi-squared test or Fisher\u0026rsquo;s exact test. Predictive variables were selected using LASSO regression, and independent risk factors were identified through multivariable logistic regression. Binary logistic regression was used to evaluate the effect of IVCT on the risk of PE in subgroup analysis. A two-sided \u003cem\u003eP\u003c/em\u003e-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant. Statistical analyses were performed using R software (version 4.2.1; R Development Core Team) and SPSS version 26.0 (IBM Corp., Armonk, NY, USA).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 3047 patients were diagnosed with LEDVT during the study period. After exclusion of\u0026nbsp;118 patients,\u0026nbsp;2929 patients with LEDVT were included in\u0026nbsp;the analysis. The patient inclusion flowchart is summarized in Fig. 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eBaseline and clinical characteristics of patients\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmong 2929 LEDVT patients, 1198 (40.9%) patients with PE were categorized as the PE group, and 1731 (59.1%) patients without PE were categorized as the non-PE group. Table 1 compares the demographic and clinical characteristics of\u0026nbsp;the patients\u0026nbsp;in the two groups. The mean age of patients with PE was 59.2 \u0026plusmn; 14.5 years, and the mean age of patients without PE was 55.4 \u0026plusmn; 15.5 years. Patients with PE were older than patients without PE (\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001). Of\u0026nbsp;the patients with PE, 49.7% were male, whereas 45.6% of patients without PE were male. The proportion of male\u0026nbsp;patients with PE was higher than that of male patients without PE (\u003cem\u003eP\u003c/em\u003e = 0.035). The proportion of patients with heart rate\u0026nbsp;\u0026gt;100 bpm in the PE group was higher than that in the non-PE group (\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001), but there was no difference in systolic blood pressure between patients with PE and patients without PE. Furthermore, patients with PE were more likely to have bilateral LEDVT (18.4% vs. 10.9%, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001), proximal LEDVT (88.1% vs. 82.6%, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001), chronic heart disease (7.2% vs. 2.4%, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001), nephrotic syndrome (2.8% vs. 1.3%, \u003cem\u003eP\u003c/em\u003e = 0.008), or infection (9.9% vs. 4.6%, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001) than those without PE. No significant differences were observed for paralytic stroke, autoimmune disease, malignant tumour, immobilisation, lower limb\u0026nbsp;fracture, leg varicosities, pregnancy or postpartum period, blood transfusion,\u0026nbsp;or smoking. The D-dimer level was higher in patients with PE than that in patients without PE (median: 5.8 \u0026mu;g/mL vs. 3.6 \u0026mu;g/mL, \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001). Similarly, the proportion of positive AADD\u0026nbsp;results in patients with PE was higher than that in patients without PE (93.8% vs. 82.5%,\u0026nbsp;\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001). In addition, IVCT was noted in 12.8% (374/2929) of\u0026nbsp;the patients. The proportion of IVCT in patients with PE was higher than that in patients without PE (16.0% vs. 10.5%,\u0026nbsp;\u003cem\u003eP\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIVCT as an independent risk factor for PE\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFirst, we used LASSO regression to select predictive variables associated with the occurrence of PE in patients with LEDVT. The variation characteristics of the coefficients of these variables are shown in Fig. 2a. The 10-fold cross-validation method was applied to the iterative analysis, and a model with excellent performance but a minimum number of variables was obtained when \u0026lambda; was 0.02025312 (Log (\u0026lambda;) = -3.899446) (Fig. 2b). After LASSO regression, eight risk factors were selected: age, LEDVT limb, IVCT, LEDVT type, infection, heart rate, chronic heart failure, and AADD (Fig. 2c).\u003c/p\u003e\n\u003cp\u003eIndependent risk factors were identified using multivariate logistic regression. The results showed that IVCT (OR 1.42; 95% CI 1.13-1.79, P = 0.003), age (OR 1.02; 95% CI 1.01-1.02, P \u0026lt; 0.001), right LEDVT (OR 1.21; 95% CI 1.01-1.45, P = 0.043), bilateral LEDVT (OR 1.87; 95% CI 1.49-2.35, P \u0026lt; 0.001), proximal LEDVT (OR 1.53; 95% CI 1.22-1.92, P \u0026lt; 0.001), chronic heart failure (OR 2.55; 95% CI 1.74-3.80, P \u0026lt; 0.001), infection (OR 2.00; 95% CI 1.48-2.73, P \u0026lt; 0.001), heart rate \u0026gt;100 bpm (OR 1.97; 95% CI 1.53-2.55, P \u0026lt; 0.001), or positive AADD (OR 3.00; 95% CI 2.29-3.97, P \u0026lt; 0.001) were independent risk factors for PE in patients with LEDVT (Fig. 3).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eImpact of IVCT on risk of PE in different subgroup\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBy dividing the study population into subgroups based on LEDVT limb and LEDVT type, we further compared the risk of PE in patients\u0026nbsp;with LEDVT with or without IVCT. The results showed that IVCT was associated with increased odds of PE in patients with left LEDVT (OR 2.00; 95% CI 1.50-2.67, \u003cem\u003eP\u003c/em\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026lt; 0.001), patients with right LEDVT (OR 2.05; 95% CI 1.20-3.50, \u003cem\u003eP\u003c/em\u003e = 0.008), patients with distal LEDVT (OR 5.15; 95% CI 1.31-20.22, \u003cem\u003eP\u003c/em\u003e = 0.019), and patients with proximal LEDVT (OR 1.48; 95% CI 1.19-1.86, \u003cem\u003eP\u003c/em\u003e = 0.001). In contrast, IVCT was associated with decreased odds of PE in patients with bilateral LEDVT (OR 0.61; 95% CI 0.38-0.95, \u003cem\u003eP\u003c/em\u003e = 0.030) (Table 2, Fig. 4).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAssociation between PE severity, risk stratification, and IVCT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe severity of PE was assessed using the PESI score. In classes\u0026nbsp;Ⅰ,\u0026nbsp;Ⅱ, Ⅲ, Ⅳ, and Ⅴ of PESI score, the proportions of patients with IVCT were 37.5%, 39.1%, 14.6%, 4.7%, and 4.2%, respectively, compared with 32.6%, 41.9%, 15.9%, 4.9%, and 4.7% of patients without IVCT, respectively. There\u0026nbsp;were no statistically significant differences between the groups (\u003cem\u003eP\u003c/em\u003e = 0.780) (Table 3; Fig. 5a). We also assessed risk stratification for early death in patients\u0026nbsp;with PE. The proportions of patients with IVCT at low, intermediate-low, intermediate-high, and high risk were 60.9%, 7.8%, 18.8%, and 12.5%, respectively. The proportions\u0026nbsp;of patients without IVCT at low, intermediate-low, intermediate-high, and high risk were 58.9%, 11.2%, 17.2%, and 12.6%, respectively. There\u0026nbsp;were no statistically significant differences between the groups (\u003cem\u003eP\u003c/em\u003e = 0.552) (Table 3; Fig. 5b).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis retrospective observational study investigated the effect of IVCT on the incidence of PE in a cohort of patients with LEDVT. The incidence of PE was higher in patients with LEDVT with concomitant IVCT, and IVCT was an independent risk factor for the occurrence of PE. However, IVCT did not affect PE severity or risk stratification.\u003c/p\u003e \u003cp\u003eIn the present study, 12.8% of LEDVT cases were complicated by IVCT. As previously reported, the incidence of IVCT is 4\u0026ndash;15% in patients with LEDVT\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Our results fall between the results of previous studies. Some previous studies on LEDVT showed that LEDVT can trigger an increased risk of IVCT with extension of the thrombus burden\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Our study included patients hospitalised with LEDVT, most of whom had proximal or extensive thrombosis. Thus, we obtained an incidence of IVCT at the high level of the range.\u003c/p\u003e \u003cp\u003eMany studies have demonstrated that LEDVT is associated with an increased incidence of PE; however, the association between concomitant IVCT and PE in patients with LEDVT has not been well elucidated. A previous study showed that symptomatic PE was more frequently observed in patients with IVCT when compared with sex- and age-matched patients with LEDVT, but the difference was not significant (27% vs. 12%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.064) \u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Another previous study also showed that patients with IVCT had a higher PE risk than patients without IVCT, but the difference was also not statistically significant (62.5% vs. 54.2%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.329) \u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. These results may be influenced by the small sample size of the studies and the presence of some confounding variables. In the present study, the incidence of PE was significantly higher in patients with LEDVT with concomitant IVCT than in patients with LEDVT alone (51.3 vs. 39.4%, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and multivariate logistic regression showed that IVCT is one of the independent risk factors for PE in patients with LEDVT (OR, 1.42; 95%CI, 1.13\u0026ndash;1.79, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.003). The probability of PE is known to be higher in patients with proximal LEDVT than in patients with distal LEDVT\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e,\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. Similarly, our study showed that patients with proximal LEDVT had a higher risk of PE than those with distal LEDVT, which is consistent with the results of previous studies\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. The above evidence suggests that the location of the thrombus is associated with PE risk, which may be related to different clot burden and embolic potential. IVCT is located in the inferior vena cava and is closer to the lungs. It may have a larger clot burden or higher embolic potential than LEDVT. Hence, LEDVT combined with IVCT is more likely to result in PE than LEDVT alone. Regarding the association between the LEDVT limb and PE, our study found that the risk of PE was in the order bilateral LEDVT\u0026thinsp;\u0026gt;\u0026thinsp;right LEDVT\u0026thinsp;\u0026gt;\u0026thinsp;left LEDVT. Li et al. and Shi et al. reported that patients with right LEDVT have a higher risk of PE than those with left LEDVT\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. This phenomenon may be due to anatomical factors such as frequent compression of the left common iliac vein, which may lead to DVT, but at the same time may prevent thrombi from escaping from the lower extremity veins to lungs\u003csup\u003e\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. A study by Zhang et al. also drew the same conclusion. They provided a different explanation, suggesting that it may be related to more comorbidities in patients with right LEDVT\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. However, the proportion of comorbidities did not differ between the right and left LEDVT groups in our study. Therefore, we believe that their explanation requires further exploration. Previous DVT studies have paid little attention to bilateral LEDVT. A previous retrospective case-control study showed that patients with bilateral LEDVT exhibited a 2.4-fold higher risk of PE than those with unilateral LEDVT\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. In the present study, we subdivided patients with unilateral LEDVT into left and right LEDVT and obtained consistent results. We believe that patients with bilateral LEDVT tend to have greater thrombotic extent and heavier thrombus burden, resulting in a higher risk of PE. In addition, we found that age, chronic heart failure, infection, heart rate\u0026thinsp;\u0026gt;\u0026thinsp;100 bpm, and positive AADD results were independent risk factors for PE in patients with LEDVT. Of these, age, heart failure, infection, and AADD are widely recognised risk factors for VTE\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. However, the association between these factors and PE in patients with LEDVT has not yet been elucidated. Therefore, further studies are warranted. A heart rate\u0026thinsp;\u0026gt;\u0026thinsp;100 bpm is one of the items of the Wells score. The Wells score has been used to distinguish patients with suspected PE from those with DVT, and our study confirmed its predictive role for PE.\u003c/p\u003e \u003cp\u003eTo further clarify the relationship between concomitant IVCT and PE at different LEDVT sites, the study population was divided into subgroups. The results showed that in the left, right, proximal, and distal LEDVT subgroups, the risk of PE was higher in patients with IVCT than in those without IVCT. Unexpectedly, however, these results were reversed in patients with bilateral LEDVT. IVCT has been reported to result in fatal PE; the patient in the report died on the way to the emergency room\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. Furthermore, the mortality rate of IVCT is 2-fold higher than that of LEDVT alone\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. In view of the above, we speculate that some patients with bilateral LEDVT and concomitant IVCT who have a very heavy thrombus burden may have fatal or severe PE, leading to death before admission or abandonment of treatment in the emergency department. This subset of patients could not be included in the present study; thus, the risk of PE is underestimated in patients with bilateral LEDVT and IVCT. We believe that the risk of PE is higher in patients with bilateral LEDVT and IVCT than in those without IVCT. Further studies are required to clarify this issue. Interestingly, patients with distal LEDVT and IVCT had a 5-fold higher risk of PE than those without IVCT. The increased risk in distal LEDVT was higher than that in proximal LEDVT. Therefore, clinicians should pay more attention to patients with distal LEDVT to identify the potential risk of IVCT and prevent the occurrence of PE.\u003c/p\u003e \u003cp\u003eIn the present study, we evaluated the association between IVCT and PE severity and risk stratification. The PESI class and risk stratification for PE represent the risk of death within the first 30 days\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. There was no difference in the severity and risk stratification of PE between patients with and without IVCT. This result may be associated with active and adequate therapy for all hospitalised patients. Although a previous study suggested that IVCT was a risk factor for silent PE\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e, it is known that the presence or absence of symptoms of PE does not fully reflect the severity. Currently, few studies have investigated the prognosis of patients with LEDVT and concomitant IVCT. Previously, a prospective observational study compared the outcomes of IVCT and LEDVT and concluded that the 24-month all-cause mortality rate was higher in patients with IVCT than in those with LEDVT\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. However, in-hospital and short-term outcomes were not reported.\u003c/p\u003e \u003cp\u003eThe present study has several limitations. First, this was a single-centre retrospective cohort study, and selection bias may have been unavoidable. Second, some risk factors for VTE, such as thrombophilia, hormone replacement therapy, and oral contraceptive use, were not analysed in this study because of the inability to obtain accurate information. Third, we did not consider medication use. Some patients used anticoagulants before admission, which may have influenced the D-dimer levels and prevented thrombus extension and subsequent PE. Fourth, we lacked data on the time from LEDVT diagnosis to the occurrence of PE and the time from LEDVT diagnosis to the appearance of IVCT, so we did not evaluate the association between IVCT and PE occurrence longitudinally. Despite these limitations, to our knowledge, our study is the first to investigate the effect of concomitant IVCT on PE in patients with LEDVT. Large-scale prospective multicentre studies are needed to verify these results.\u003c/p\u003e \u003cp\u003eIn conclusion, concomitant IVCT was associated with a significantly increased risk for PE compared with no IVCT among patients with LEDVT, and was an independent risk factor for PE. However, IVCT did not affect PE severity or risk stratification. Our finding could contribute to further improve the understanding of IVCT among clinicians, and suggest that, when managing patients with LEDVT, it is important to focus on identifying IVCT and adjust the monitoring and management strategies based on the presence or absence of IVCT.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank to Xinye Yao and Bowen Fu (Xi\u0026rsquo;an Jiaotong University) for the data collection. We also thank Nurse Manager Zhou Hongyan (Department of Peripheral Vascular Diseases, The First Affiliated Hospital of Xi\u0026rsquo;an Jiaotong University) for patient care.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eY.Z., Q.Y. and H.T. designed the study. Y.M., Y.L. and M.K. collected the data. Y.Z., Q.M., J.Z. and Q.Y. analysed and interpreted the data. Y.Z. drafted the manuscript. Y.M., Y.L., M.K., Q.M., J.Z., J.Y., H.T. and Q.Y. revised the manuscript. All authors have read and approved this manuscript for submission.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFinding\u0026nbsp;\u003c/strong\u003eThis study was supported by the Key Industry Innovation Chain Project of Shaanxi province, China (No. 2022ZDLSF02-02) and the Clinical Research Award of The First Affiliated Hospital of Xi\u0026rsquo;an Jiaotong University, China (No. XJTU1AF-CRF-2018-021).\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eOur data is available from the corresponding authors on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKhan, F., Tritschler, T., Kahn, S. R., Rodger, M. A. Venous thromboembolism. Lancet. 398, 64\u0026ndash;77 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJim\u0026eacute;nez, D. et al. Trends in the Management and Outcomes of Acute Pulmonary Embolism: Analysis From the RIETE Registry. J Am Coll Cardiol. 67, 162\u0026ndash;70 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarco, S. et al. Trends in mortality related to pulmonary embolism in the European Region, 2000-15: analysis of vital registration data from the WHO Mortality Database. Lancet Respir Med. 8, 277\u0026ndash;87 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLutsey, P. L., Zakai, N. A. Epidemiology and prevention of venous thromboembolism. Nat Rev Cardiol. 20, 248\u0026ndash;62 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKahn, S. R., de Wit, K. Pulmonary Embolism. N Engl J Med. 387, 45\u0026ndash;57 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlkhouli, M., Morad, M., Narins, C. R., Raza, F., Bashir, R. Inferior Vena Cava Thrombosis. JACC Cardiovasc Interv. 9, 629\u0026ndash;43 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLin, H. Y., Lin, C. Y., Shen, M. C. Review article inferior vena cava thrombosis: a case series of patients observed in Taiwan and literature review. Thromb J. 19, 43 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMcAree, B. J. et al. Inferior vena cava thrombosis: a review of current practice. Vasc Med. 18, 32\u0026ndash;43 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShi, W., Dowell, J. D. Etiology and treatment of acute inferior vena cava thrombosis. Thromb Res. 149, 9\u0026ndash;16 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKakkos, S. K. et al. Editor's Choice - European Society for Vascular Surgery (ESVS) 2021 Clinical Practice Guidelines on the Management of Venous Thrombosis. Eur J Vasc Endovasc Surg. 61, 9\u0026ndash;82 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKonstantinides, S. V. et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism developed in collaboration with the European Respiratory Society (ERS). Eur Heart J. 41, 543\u0026ndash;603 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAvgerinos, E. D. et al. Impact of inferior vena cava thrombus extension on thrombolysis for acute iliofemoral thrombosis. J Vasc Surg Venous Lymphat Disord. 4, 385\u0026ndash;91 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKraft, C. et al. Patients with inferior vena cava thrombosis frequently present with lower back pain and bilateral lower-extremity deep vein thrombosis. Vasa. 42, 275\u0026ndash;83 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGong, M. et al. Risk factors and a predictive model for nonfilter-associated inferior vena cava thrombosis in patients with lower extremity deep vein thrombosis. Front Cardiovasc Med. 9, 1083152 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamaki, T. et al. Factors predicting development of post-thrombotic syndrome in patients with a first episode of deep vein thrombosis: preliminary report. Eur J Vasc Endovasc Surg. 41, 126\u0026ndash;33 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKonstantinides, S. V. et al. 2014 ESC guidelines on the diagnosis and management of acute pulmonary embolism. Eur Heart J. 35, 3033\u0026ndash;69, 69a-69k (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoc, A., Vene, N., Stalc, M., Košmelj, K., Mavri, A. Unprovoked proximal venous thrombosis is associated with an increased risk of asymptomatic pulmonary embolism. Thromb Res. 133, 1011\u0026ndash;5 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKucher, N., Tapson, V. F., Goldhaber, S. Z. Risk factors associated with symptomatic pulmonary embolism in a large cohort of deep vein thrombosis patients. Thromb Haemost. 93, 494\u0026ndash;8 (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi, F. et al. Risk factors associated with the occurrence of silent pulmonary embolism in patients with deep venous thrombosis of the lower limb. Phlebology. 29, 442\u0026ndash;6 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShi, Y. et al. Impact of Common Iliac Vein Compression on the Incidence of Pulmonary Embolism in Patients with Acute Deep Vein Thrombosis. Eur J Vasc Endovasc Surg. 65, 887\u0026ndash;94 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen, F., Huang, J. G., Liu, X., Zhou, W. Left iliac vein involvement is a protective factor against symptomatic pulmonary embolism in lower left extremity deep vein thrombosis. J Vasc Surg Venous Lymphat Disord. 10, 1272\u0026ndash;78 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang, C. et al. Relationship between the site of thrombosis and the prevalence of pulmonary embolism in acute lower extremity deep venous thrombosis. J Vasc Surg Venous Lymphat Disord. 8, 725\u0026ndash;33 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang, J. et al. Anatomic distribution of lower extremity deep venous thrombosis is associated with an increased risk of pulmonary embolism: A 10-year retrospective analysis. Front Cardiovasc Med. 10, 1154875 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFreund, Y., Cohen-Aubart, F., Bloom, B. Acute Pulmonary Embolism: A Review. JAMA. 328, 1336\u0026ndash;45 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHanterdsith, B. Fatal Pulmonary Thromboembolism due to Inferior Vena Cava Thrombosis. Ann Vasc Dis. 4, 121\u0026ndash;3 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShi, Y. et al. Silent Pulmonary Embolism in Deep Vein Thrombosis: Relationship and Risk Factors. Clin Appl Thromb Hemost. 28, 10760296221131034 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCohen, O. et al. Management strategies and clinical outcomes in patients with inferior vena cava thrombosis: Data from GARFIELD-VTE. J Thromb Haemost. 20, 366\u0026ndash;74 (2022).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Baseline and clinical characteristics of patients with and without PE\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"555\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=2929)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003ePE\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=1198)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eNo PE\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=1731)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eAge - years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e57.0\u0026nbsp;\u0026plusmn; 15.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e59.2\u0026nbsp;\u0026plusmn; 14.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e55.4\u0026nbsp;\u0026plusmn; 15.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1385 (47.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e595 (49.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e790 (45.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.035\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eHeart rate - bpm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026le; 100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e2633 (89.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1024 (85.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1609 (93.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026gt;\u0026nbsp;100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e296 (10.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e174 (14.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e122 (7.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eSBP - mmHg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e124.0\u0026nbsp;\u0026plusmn; 18.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e125.0\u0026nbsp;\u0026plusmn; 17.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e124.0\u0026nbsp;\u0026plusmn; 18.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.145\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eLEDVT limb\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eLeft limb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1776 (60.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e677 (56.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1099 (63.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eRight limb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e745 (25.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e301 (25.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e444 (25.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eBilateral limbs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e408 (13.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e220 (18.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e188 (10.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eLEDVT type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eProximal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e2486 (84.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1056 (88.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1430 (82.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eDistal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e443 (15.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e142 (11.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e301 (17.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eComorbidities\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eChronic heart failure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e128 (4.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e86 (7.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e42 (2.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eParalytic stroke\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e136 (4.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e54 (4.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e82 (4.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.841\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eAutoimmune disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e143 (4.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e55 (4.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e88 (5.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.602\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eNephrotic syndrome\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e56 (1.91%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e33 (2.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e23 (1.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.008\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eRisk factors\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eMalignant tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e379 (12.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e161 (13.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e218 (12.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.539\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eImmobilization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e813 (27.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e311 (26.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e502 (29.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.078\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eFracture of lower limb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e261 (8.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e117 (9.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e144 (8.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.199\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eLeg varicosities\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e161 (5.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e59 (4.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e102 (5.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.295\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003ePregnancy/postpartum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e120 (4.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e39 (3.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e81 (4.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.058\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eInfection\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e199 (6.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e119 (9.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e80 (4.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eBlood transfusion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e123 (4.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e52 (4.34%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e71 (4.10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.823\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eSmoking\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e739 (25.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e322 (26.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e417 (24.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e0.096\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eD-dimer -\u0026nbsp;\u0026mu;g/mL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e4.4 (1.7-9.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e5.8 (2.6-11.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e3.6 (1.1-8.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eAADD positive\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e2552 (87.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1124 (93.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e1428 (82.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.31654676258993%\" valign=\"top\"\u003e\n \u003cp\u003eIVCT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e374 (12.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e192 (16.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"19.06474820143885%\"\u003e\n \u003cp\u003e182 (10.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"13.489208633093526%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eData are presented as mean \u0026plusmn; standard deviation, n (%), or median (interquartile range). PE, pulmonary embolism; SBP, systolic blood pressure; LEDVT, lower extremity deep vein thrombosis; AADD, age-adjusted D-dimer; IVCT, inferior vena cava thrombosis\u003cbr\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Subgroup analysis for the association between PE and IVCT\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"556\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.3971119133574%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eIVCT\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=374)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eNon-IVCT\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=2 555)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.826714801444044%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eOR (95% CI)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.981949458483754%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003evalue\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003eLEDVT limb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.826714801444044%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.981949458483754%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003eLeft\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e114 (53.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e563 (36.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.826714801444044%\"\u003e\n \u003cp\u003e2.00 (1.50-2.67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.981949458483754%\"\u003e\n \u003cp\u003e\u0026lt; 0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003eRight\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e34 (56.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e267 (39.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.826714801444044%\"\u003e\n \u003cp\u003e2.05 (1.20-3.50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.981949458483754%\"\u003e\n \u003cp\u003e0.008\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003eBilateral\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e44 (44.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e176 (57.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.826714801444044%\"\u003e\n \u003cp\u003e0.61 (0.38-0.95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.981949458483754%\"\u003e\n \u003cp\u003e0.030\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003eLEDVT type\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.826714801444044%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.981949458483754%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003eDistal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e7 (70.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e135 (31.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.826714801444044%\"\u003e\n \u003cp\u003e5.15 (1.31-20.22)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.981949458483754%\"\u003e\n \u003cp\u003e0.019\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003eProximal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e185 (50.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.3971119133574%\"\u003e\n \u003cp\u003e871 (41.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.826714801444044%\"\u003e\n \u003cp\u003e1.48 (1.19-1.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.981949458483754%\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eBinary logistic regression was performed to obtain the OR with a 95% CI of PE. PE, pulmonary embolism; IVCT, inferior vena cava thrombosis; LEDVT, lower extremity deep vein thrombosis; OR, odds ratio; CI, confidence interval\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e \u003cstrong\u003eTable 3.\u003c/strong\u003e Comparison of PESI class and risk stratification of PE between patients with and without IVCT\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eIVCT\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=192)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003eNon-IVCT\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=1 006)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\" valign=\"bottom\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eP\u003c/em\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003ePESI score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e0.780\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eClass Ⅰ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e72 (37.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e328 (32.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eClass Ⅱ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e75 (39.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e422 (41.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eClass Ⅲ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e28 (14.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e160 (15.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eClass Ⅳ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e9 (4.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e49 (4.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eClass Ⅴ\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e8 (4.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e47 (4.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eRisk stratification\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e0.552\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eLow\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e117 (60.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e593 (58.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eIntermediate-low\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e15 (7.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e113 (11.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eIntermediate-high\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e36 (18.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e173 (17.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"29.09090909090909%\" valign=\"top\"\u003e\n \u003cp\u003eHigh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"27.454545454545453%\"\u003e\n \u003cp\u003e24 (12.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"29.272727272727273%\"\u003e\n \u003cp\u003e127 (12.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"14.181818181818182%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003ePESI, Pulmonary Embolism Severity Index; IVCT, inferior vena cava thrombosis\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Inferior vena cava thrombosis, Pulmonary embolism, Lower extremity deep vein thrombosis, Risk factors","lastPublishedDoi":"10.21203/rs.3.rs-4590808/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4590808/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eInferior vena cava thrombosis (IVCT) is a special form of venous thromboembolism. Lower extremity deep vein thrombosis (LEDVT) is associated with an increased incidence of pulmonary embolism (PE), but the association between concomitant IVCT and PE in patients with LEDVT has not been reported. We conducted a retrospective analysis of clinical data from patients confirmed with LEDVT at the First Affiliated Hospital of Xi\u0026rsquo;an Jiaotong University. Predictive variables of PE were selected using LASSO regression, and independent risk factors were identified through multivariable logistic regression. Of the 2929 patients, 40.9% had PE and 12.8% had IVCT. Multivariable logistic regression suggested that IVCT (OR 1.42, 95% CI 1.13\u0026ndash;1.79) was an independent risk factor for PE. Subgroup analysis showed that IVCT was associated with increased odds of PE in patients with left LEDVT (OR 2.00, 95% CI 1.50\u0026ndash;2.67), right LEDVT (OR 2.05, 95% CI 1.20\u0026ndash;3.50), distal LEDVT (OR 5.15, 95% CI 1.31\u0026ndash;20.22), and proximal LEDVT (OR 1.48, 95% CI 1.19\u0026ndash;1.86). Concomitant IVCT significantly increased the incidence of PE in patients with LEDVT. There was no difference in PE severity or risk stratification between patients with and without IVCT. These finding could contribute to further improve the understanding of IVCT among clinicians, and optimize monitoring and management strategies of patients with LEDVT.\u003c/p\u003e","manuscriptTitle":"Impact of inferior vena cava thrombosis on the incidence of pulmonary embolism in patients with lower extremity deep vein thrombosis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-18 15:22:19","doi":"10.21203/rs.3.rs-4590808/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-01-28T05:15:46+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-01-26T22:33:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"4673083050927131477165451419758907692","date":"2025-01-13T20:01:01+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-09-09T07:12:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"65943563344545101219451306171105393917","date":"2024-08-26T22:03:35+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-06-30T11:37:56+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-30T11:37:17+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-06-19T08:34:51+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-19T08:31:49+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2024-06-16T19:51:11+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2e20d9a5-4bf7-4cd1-9675-1b5fd2d01b82","owner":[],"postedDate":"July 18th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":34143229,"name":"Health sciences/Diseases/Cardiovascular diseases/Vascular diseases/Thromboembolism"},{"id":34143230,"name":"Health sciences/Diseases/Cardiovascular diseases/Vascular diseases/Thrombosis"},{"id":34143231,"name":"Health sciences/Risk factors"}],"tags":[],"updatedAt":"2025-06-09T16:05:17+00:00","versionOfRecord":{"articleIdentity":"rs-4590808","link":"https://doi.org/10.1038/s41598-025-04377-7","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-06-05 15:56:53","publishedOnDateReadable":"June 5th, 2025"},"versionCreatedAt":"2024-07-18 15:22:19","video":"","vorDoi":"10.1038/s41598-025-04377-7","vorDoiUrl":"https://doi.org/10.1038/s41598-025-04377-7","workflowStages":[]},"version":"v1","identity":"rs-4590808","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4590808","identity":"rs-4590808","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}