Do fistula flow rate and fistula location have any effects on heart failure developing in patients with arteriovenous fistula? 

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Gündüz Yümün, Mehmet Okan Donbaloğlu, Selami Gürkan, Özcan Gür, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5898012/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 04 Jul, 2025 Read the published version in BMC Cardiovascular Disorders → Version 1 posted 4 You are reading this latest preprint version Abstract Background This study aims to explore the effects of arteriovenous fistula locations in the arm and fistula flow rates on the potential development of heart failure in patients with arteriovenous fistula (AVF). Material and Methods A total of 116 patients with AVF due to chronic kidney disease (CKD) were retrospectively reviewed between January 2022 and August 2022. Fifty-six patients with distal AVFs and 60 with proximal AVFs were compared in terms of demographic, clinical, and echocardiographic (ECHO) characteristics. Fistula flow rates were assessed using Doppler ultrasonography (DUS), while cardiac parameters were evaluated with ECHO. The correlation between fistula location and cardiac parameters was analyzed using ROC analysis. Results The mean AVF blood flow rate (Qa) was 1.47 (0.57–2.9) L/min for proximal fistulas and 0.85 (0.52–2.3) L/min for distal fistulas. There were statistically significant differences between the proximal and distal AVF groups regarding cardiac index (CI), cardiac output (CO), and cardiopulmonary recirculation (CPR) values (P < 0.001). According to the New York Heart Association (NYHA) classification, Class III can be categorized as high cardiac output failure (HCOF), as CI was calculated at 6.87 ± 1.65 L/min/m² (4.7–9.4), Qa at 2.60 L/min (2.1–2.9), and CO at 8.08 ± 0.69 L/min. Conclusions When heart failure develops in patients with AVF, underlying heart disease should not be the sole factor considered. Proximal high-flow AVFs, in particular, may contribute to heart failure development and warrant careful monitoring. Hemodialysis Fistula Location Fistula Flow Rate Heart Failure Figures Figure 1 Figure 2 1. Intraduction End-stage renal disease (ESRD) is a clinical condition that affects nearly all organ systems and can be life-threatening if untreated. Due to the insufficient number of kidney transplants, hemodialysis remains the most commonly used treatment method. Among vascular access options, arteriovenous fistula (AVF) is considered the safest and most durable, with the lowest rates of mortality and morbidity [ 1 , 2 ]. Effective hemodialysis requires sufficient blood flow, durability, and easy, repeatable cannulation. AVFs are categorized by their location as proximal (e.g., brachiocephalic, brachiobasilic) or distal (e.g., snuffbox, radiocephalic). However, complications such as bleeding, infection, hematoma, thrombosis, stenosis, ischemic neuropathy, skin necrosis, steal syndrome, aneurysm/pseudoaneurysm, and high cardiac output failure (HCOF) are associated with AVFs. Fistula flow rate (Qa) plays a critical role in ensuring effective hemodialysis. While low Qa may indicate vascular access issues, high Qa is hypothesized to increase cardiac output (CO), potentially leading to HCOF [ 3 ]. Studies on long-term hemodialysis patients have introduced the concept of the Qa-to-CO ratio, known as cardiopulmonary recirculation (CPR) [ 4 ]. The Vascular Access Society guidelines define high-flow AVF as one with a Qa of 1.0–1.5 L/min and a CPR > 0.20 [ 5 ]. Not all patients with high-flow AVFs develop heart failure. Some researchers suggest that HCOF, defined as symptomatic heart failure with an elevated cardiac index, is a rare complication of high-flow AVFs and usually occurs only in the presence of underlying heart disease [ 6 , 7 ]. This study aims to investigate the relationship between fistula flow rates and heart failure symptoms, the correlation of Qa with CO, and the effects of fistula location on flow and cardiac output, and echocardiographic changes in patients with AVFs. 2. Material and Methods This study included 116 chronic hemodialysis patients treated and monitored at the Cardiovascular Surgery Clinic of Tekirdağ Namık Kemal University. Patients participated in a dialysis program for at least six months between January 2022 and August 2022. Among them, 56 had distal and 60 had proximal arteriovenous fistulas (AVFs). The study was conducted in compliance with the Declaration of Helsinki principles and approved by the ethics committee of Namık Kemal University. Exclusion criteria included patients with Class IV heart failure (HF) per the New York Heart Association (NYHA) classification, a history of cardiac surgery, structural heart disease (e.g., valvular or congenital abnormalities) identified by echocardiography (ECHO), prior kidney transplantation, or graft AVFs other than native ones. Demographic data and hemodialysis (HD) duration were recorded (Table 1 ). AVF flow rate (Qa) was calculated using Doppler ultrasonography (DUS). Flow volume was determined based on AVF vessel diameter and mean flow rate using an algorithm embedded in the ultrasonography system [ 8 ]. Before transthoracic ECHO, HF symptoms were evaluated using the NYHA classification: Table 1 Demographic and clinical characteristics Mean ± SD / n(%) Age 56,3 ± 10,03 Gender Male 78 (%67,25) Female 38 (%32,75) Diabetes mellitus 30 (%25,86) Body mass index (BMI) (kg/m2) 23,5 ± 3,58 30 2 (%1,72) Hypertension 50 (%43.1) AVF duration (months) 46,1 ± 18,12 Hemoglobin (gr/dl) 11,25 ± 1,82 Myocardial infarction 2 (%1,7) Cerebrovascular disease 2 (%1,7) Systolic blood pressure (mm/hg) 127,1 ± 21,7 Diastolic blood pressure (mm/hg) 74,5 ± 15,6 Hemodialysis time 4 h - Frequency of hemodialysis 2 times a week 6 (%5) 3 times a week 110 (%95) (Data Mean ± SD; Median(Min-Max); summarized as n(%)). Class I : No limitation of physical activity. Class II : Slight limitation of physical activity (HF symptoms with ordinary activity but not at rest). Class III : Marked limitation of physical activity (HF symptoms with mild activity but not at rest). Class IV : Symptoms of HF at rest (Table 2 ). Table 2 Clinical characteristics of patients according to the location of AVFs Proximal AVF Distal AVF (n = 60) (n = 56) p Age 58,3 ± 9,9 53,9 ± 9,6 0,011 BMI 24,5 ± 3,5 22,5 ± 3,3 0,002 AV fistula duration 54(28–82) 34(16–80) 0,0001 Hemoglobin 10,7 ± 1,4 11,8 ± 2,0 0,001 Systolic blood pressure (mm/hg) 127,2 ± 22,3 121,1 ± 22,8 0,148 Diastolic blood pressure (mm/hg) 74,5 ± 15,7 74,3 ± 17,8 0,945 (Data Mean ± SD; Summarized as Median(Min-Max) Patients were classified and recorded per the NYHA stages of HF at baseline and during follow-up. Class III was considered high cardiac output failure (HCOF) only if the cardiac index (CI) exceeded normal values (> 3.0 L/min/m²) [ 9 ]. Heart failure symptoms included dyspnea, paroxysmal nocturnal dyspnea, orthopnea, and pulmonary and/or peripheral edema, assessed in conjunction with an elevated CI (> 3.0 L/min/m²) [ 9 ]. Cardiac parameters, including left ventricular and left atrial functions, pulmonary arterial pressure, cardiac output (CO), ejection fraction (EF), and heart rate, were calculated via ECHO. Patients were grouped based on fistula location (Tables 3 – 4 ). Assessments were performed within 24 hours post-dialysis, midweek. Table 3 Distribution of echocardiographic parameters according to groups Proximal AVF (n = 60) Distal AVF (n = 56) p LV diastolic diameter (LVDD) (mm) 55,36 ± 7,85 50,63 ± 4,74 0,001 LV systolic diameter (LVSD) (mm) 40,24 ± 8,14 35,84 ± 5,46 0,001 Diastolic IVS (mm) 11,85 ± 1,55 10,96 ± 0,75 0,668 Diastolic posterior wall (mm) 10,46 ± 1.63 11,65 ± 1,67 0,842 LV diastolic volume (LVDV) (ml) 110 ± 18 70 ± 16 0,0001 LV systolic volume (LVSV) (ml) 46 ± 10 33 ± 8 0,001 LA diameter (mm) 43,6 ± 5,6 39,2 ± 4,5 0,0001 LA volume (ml/m2) 50 ± 21 37 ± 7 0,0001 EF (modified Simpson’s method) (%) 51,5 ± 8,7 57,0 ± 78 0,001 Systolic PAP (mmHg) 33,56 ± 9,84 28,75 ± 9,66 0,001 LV mass index (g/m2) 158.93 ± 80.76 108.56 ± 43.24 0,0001 (Data are expressed as mean ± SD or percentage. LV ; left ventricle, IVS; interventricular septum, LA; left atrium, PAP; pulmonary artery pressure, EF; ejection). Table 4 Cardiac characteristics of patients according to the location of AVFs Proximal AVF Distal AVF (n = 60) (n = 56) p AVF blood flow rate (l/min) (Qa) 1,47 (0,57 − 2,9) 0,85(0,52 − 2,3) 0,0001 EF (%) 51,5 ± 8,7 57,0 ± 78 0,001 Cardiac output (l/min) (CO) 6,6 ± 1,2 5,7 ± 1,1 0,0001 Cardiac index (CI) 5,4(3,1–9,4) 3,3(2,6–8,9) 0,0001 Cardiopulmonary recirculation (CPR, %) 24,6 ± 6,7 16,4 ± 5,4 0,0001 Heart rate (atm/min) 72,4 ± 15,8 72 ± 13,8 0,866 NYHA classification Class I 10(%16,6) 28(%50) 0,0001 Class II 34(%56,7) 26(%46,4) Class III 16(%26,7) 2(%3,6) (Data Mean ± SD; Median(Min-Max); summarized as n(%)). Statistical Analysis : SPSS 25.0 software was used for data analysis. Categorical variables were summarized as numbers and percentages, while continuous variables were expressed as means and standard deviations (or medians with minimum and maximum values, as necessary). Categorical variables were compared using the Chi-square or Fisher’s exact test. Continuous variables were analyzed with one-way ANOVA or Student’s t-test for parametric distributions and the Kruskal-Wallis or Mann-Whitney U test for non-parametric distributions. Receiver operating characteristic (ROC) curve analysis was used to calculate sensitivity and specificity for AVF location cut-off values. Statistical significance was set at P < 0.05 for all tests. 3. Results The study included 116 patients, of whom 78 (67.25%) were male, and 38 (32.75%) were female. The mean age was 56.3 ± 10.03 years. Table 1 provides demographic and clinical characteristics of the patients. The mean body mass index (BMI) was 23.5 ± 3.58, with 68 patients classified as normal weight (BMI 18–25), 42 as overweight (BMI 25–30), 4 as underweight (BMI 30). The mean hemoglobin (Hb) level was 11.25 ± 1.82 g/dL. Among the patients, 30 (25.86%) had diabetes mellitus (DM), 50 (43.1%) had hypertension (HT), 2 (1.7%) had a history of myocardial infarction, and 2 (1.7%) had cerebrovascular disease. The mean systolic blood pressure was 127.1 ± 21.7 mmHg, and the diastolic blood pressure was 74.5 ± 15.6 mmHg. Most patients (86%, 100 patients) underwent 4-hour dialysis sessions, with 14% (16 patients) undergoing sessions shorter than 4 hours. No patients had sessions longer than 4 hours. Additionally, 95% of patients (110) had dialysis three times a week, while 5% (6) had it twice weekly. The mean AVF duration was 46.1 ± 18.12 months, and no patients exhibited cardiac arrhythmias. Clinical and Cardiac Characteristics: Table 2 summarizes patient characteristics by AVF location: According to this, 60 patients had proximal and 56 patients had distal AVF. Statistically significant differences were observed between groups for age, BMI, AVF duration, and Hb values but not for blood pressure. Table 3 shows echocardiographic differences, including significant variations in left ventricular dimensions, volumes, and mass index, as well as left atrial parameters and pulmonary arterial pressure. AVF Flow Rate and NYHA Classification: The mean Qa was 1.47 (0.57–2.9) L/min in proximal fistulas and 0.85 (0.52–2.3) L/min in distal fistulas (P < 0.001, Table 4 ). Significant differences were also observed in CI, CO, and CPR values. NYHA classification revealed: Proximal AVF Patients : 17% in Class I, 57% in Class II, and 26% in Class III. Distal AVF Patients : 50% in Class I, 46% in Class II, and 4% in Class III. A statistically significant higher proportion of proximal AVF patients were in NYHA Classes II and III. Among the Class III patients (n = 18), all were classified as HCOF, with a CI of 6.87 ± 1.65 L/min/m², Qa of 2.60 L/min, and CO of 8.08 ± 0.69 L/min (Table 5 ). Table 5 Comparison of cardiac parameter and AVF characteristics according to NYHA classification NYHA Class I (n = 38) Class II (n = 60) Class III (n = 18) p AVF flow rate (Qa) (l/min) 0,76(0,52 − 1,2) 1,30(0,57 − 2,3) 2,60(2,1–2,9) 0,0001 EF (%) 58,10 ± 7,90 54,4 ± 7,40 45,5 ± 7,11 0,0001 Cardiac output (CO) (l/min) 5,30 ± 1,01 6,13 ± 0,81 8,08 ± 0,69 0,0001 Cardiac index (CI) (l/min/m2) 3.29 ± 0.72 4,8 ± 1.36 6,87 ± 1,65 0,0001 AVF duration (months) 24(18–36) 48(16–80) 54(28–82) 0,0001 CPR (Qa/CO) (%) 15,2 ± 4,9 19,2 ± 6,5 25,7 ± 6,7 0,0001 (Data Mean ± SD; Median(Min-Max); summarized as n(%)). The correlation between fistula locations and cardiac parameters was analyzed using ROC curve analysis. According to the ROC analysis, if the Qa value is > 1.15, the patient's AVF location is likely to be distal, with 64.3% sensitivity, 63.3% specificity, and 73.2% probability. Conversely, if the CPR % value is > 18.5, the AVF location is expected to be proximal, with 80% sensitivity, 75% specificity, and 82.7% probability. If the patient’s CO value is > 6.0, the AVF location is likely distal, with 67.9% sensitivity, 60% specificity, and 71.5% probability. Additionally, if the CI value is > 4.2, the AVF location is expected to be distal, with 75% sensitivity, 70% specificity, and 82.8% probability (Figs. 1 and 2 ). 4. Discussion The presence of an arteriovenous fistula reduces systemic vascular resistance, leading to increased stroke volume and cardiac output (CO) to maintain blood pressure [ 10 ]. This adaptation has been demonstrated by studies showing a significant increase in mean blood flow on the AVF side compared to the contralateral side [ 11 ]. For instance, brachial arterial flow rates measured via Doppler ultrasound (DUS) increased markedly from baseline values after AVF creation, underscoring the substantial hemodynamic impact of AVFs. However, the correlation between AVF flow rate (Qa) and CO remains poorly understood, with limited data on their interdependence, and it is also estimated that high fistula flow rates increase CO and lead to HCOF. Some studies suggest that high fistula flow rates (> 2.0 L/min) significantly increase CO, potentially resulting in high cardiac output failure (HCOF). Interestingly, while CO remains stable with AVF flow rates up to 2.0 L/min, further increases can overwhelm myocardial adaptation mechanisms, leading to cardiac dysfunction [ 3 , 12 ]. This phenomenon is supported by findings indicating a higher prevalence of HCOF in patients with proximal AVFs compared to distal AVFs, as proximal AVFs tend to have higher Qa and CO values [ 3 , 13 , 14 ]. Our analysis showed a parallel increase in cardiac index (CI) values and a higher number of NYHA Class III patients in the proximal AVF group, suggesting a greater risk of HCOF development in this population. When Class II was analyzed, there was no significant difference between the number of patients with proximal AVFs and those with distal AVFs; however, there was a significant difference between the groups for Classes I and III. The findings of this study emphasize the importance of monitoring AVF flow and cardiac parameters to identify patients at risk for HCOF. According to the coralation analisys a Qa value > 1.15 L/min is associated with a distal AVF, while a CPR > 18.5% and CO > 6.0 L/min suggest a proximal AVF. Additionally, a CI value > 4.2 indicates a distal AVF. Furthermore, echocardiographic data from our study revealed significant cardiac changes after AVF creation, such as increased left ventricular end-diastolic diameter (LVEDD), fractional shortening, and cardiac output (CO). Additionally, when comparing the data obtained right before and 14 days after AVF creation, significant increases were observed in left ventricular end-diastolic diameter (+ 4%), fractional shortening (+ 8%), and CO (+ 15%) [ 12 , 14 ]. In the long term, cardiac adaptation, characterized by left ventricular hypertrophy (LVH), occurs in hemodialysis patients due to volume overload [ 15 ]. While these changes are initially adaptive, they may lead to long-term complications such as LVH, diastolic dysfunction, and ultimately heart failure in patients with high-flow AVFs. The pathophysiological mechanisms linking high-flow AVFs to heart failure include chronic volume overload and increased left ventricular diastolic volume (LVDV) [ 16 – 18 ]. Evidence from both short- and long-term studies suggests that LVH and elevated left atrial volume (LAV) contribute to diastolic pressure elevation, further exacerbating cardiac dysfunction. This progression underscores the importance of identifying patients predisposed to AVF-induced cardiac decompensation. Although some authors propose that AVF-related heart failure occurs only in those with pre-existing cardiac conditions, our findings indicate that high-flow AVFs alone can trigger HCOF in patients without prior heart disease. Risk factors for high-flow AVFs include male sex, upper-arm AVF placement, and prior fistula surgeries. Additionally, our study corroborates trends from the literature showing increased LVEDV and worsening cardiac parameters in patients with Qa > 2.0 L/min. Given these findings, regular monitoring of AVF flow using DUS and cardiac function using echocardiography (ECHO) is critical. Such surveillance can help mitigate the risk of HCOF, particularly in patients with proximal AVFs. Our study’s data align with previous research emphasizing the need for threshold values, such as Qa and CPR, to guide interventions. For instance, high CPR values (≥ 20%) and high flow rates (Qa ≥ 2.0 L/min) may serve as predictive markers for cardiac risk. However, further prospective studies are required to validate these thresholds and develop comprehensive guidelines for managing high-flow AVFs. Limitations of our study include its retrospective, single-center design and the relatively small sample size (116 patients). Despite these limitations, our findings provide valuable insights into the hemodynamic and cardiac consequences of AVFs, particularly their potential to induce HCOF. Conclisions Although some studies suggest that AVF-induced cardiac decompensation may occur only in patients with underlying heart disease, our data show that one of the key findings being that the AVF Qa value is higher in proximal AVFs. Along with this result, the fact that cardiac index (CI), cardiac output (CO), and cardiac power reserve (CPR) values are also higher suggests that the risk of heart failure development is considerably greater in proximal AVFs compared to distal AVFs. Therefore, in patients with AVFs, it is crucial to monitor the fistula flow rates regularly using Doppler ultrasound (DUS) and to monitor patients for heart failure development with echocardiography (ECHO). While a high-flow AVF may be ideal for hemodialysis, but it should be remembered that any potential heart failure could be fatal unless properly monitored. Furthermore, guidelines may be developed to establish threshold Qa or CPR values for intervention to prevent high-flow AVF-induced high-output cardiac failure (HCOF). Additional prospective studies are needed to confirm whether the biologically plausible concept of high CPR (≥ 20%) and high flow rates (Qa ≥ 2.0 L/min) are indeed indicative of and related to increased cardiac risk. Declarations Conflict of interest : We have no conflict of interest. Ethics approval and consent to participate: Yes (protocol: TNKU-2022.153.07.20) Consent for publication: Yes Funding: No Availability of data and material: Yes Role of the Funding source This study was not supported by any organization. Acknowledgements No Author Contribution G.Y. and M.O.D. wrote the main manuscript text and E.F. prepared figures 1-3. G.Y., S.G., M.O.D., and Ö.G. performed fistula openings for the patients and recorded the patient characteristics.A.D. monitored the patients' heart insufficiency and systematically filed their records.All authors reviewed the manuscript. References Gilmore J. KDOQI clinical practice guidelines and clinical practice recommendations–2006 updates. Nephrol Nurs J. 2006;33:487–8. Ethier J, Dumont M, Beaulieu M, Girard R, Leblanc M. Relation between dialysis membrane characteristics and clinical outcomes. Nephrol Dial Transpl. 2008;23:3219–26. 10.1093/ndt/gfn228 . Basile C, Lomonte C, Vernaglione L, Casucci F, Antonelli M. The relationship between the flow of arteriovenous fistula and cardiac output in haemodialysis patients. Nephrol Dial Transpl. 2008;23:282–7. 10.1093/ndt/gfm586 . Pandeya S, Lindsay RM. The relationship between cardiac output and access flow during hemodialysis. ASAIO J. 1999;45:135–8. 10.1097/00002480-199903000-00010 . Vascular Access Society. (2016) Guideline 20.3. Available at: www.vascularaccesssociety.org. Accessed June 29. Beathard GA. (2017) Heart failure and hemodialysis arteriovenous fistulae. Available at: http://www.uptodate.com . Accessed May 22. London GM. Left ventricular alterations and end-stage renal disease. Nephrol Dial Transpl. 2002;17(Suppl 1):29–36. 10.1093/ndt/17.suppl_1.29 . Zamboli P, Fiorini F, D’Amelio A, Fatuzzo P, Marciano A. Color Doppler ultrasound and arteriovenous fistulas for hemodialysis. J Ultrasound. 2014;17:253–63. 10.1007/s40477-014-0102-4 . MacRae JM, Pandeya S, Humen DP, Krivitski N, Lindsay RM. (2004) Arteriovenous fistula-associated high-output cardiac failure: a review of mechanisms. Am J Kidney Dis. 2004;43:e17-e22. 10.1053/j.ajkd.2003.12.036 London GM, Guerin AP, Marchais SJ. Hemodynamic overload in end-stage renal disease patients. Semin Dial. 1999;12:77–83. 10.1046/j.1525-139x.1999.00019.x . Lomonte C, Casucci F, Antonelli M, Vernaglione L. Is there a place for duplex screening of the brachial artery in the maturation of arteriovenous fistulas? Semin Dial. 2005;18:243–6. 10.1111/j.1525-139X.2005.18209.x . Girerd X, London G, Boutouyrie P, Marnay-Gulatier E, Safar ME. Remodeling of the radial artery in response to a chronic increase in shear stress. Hypertension. 1996;27:799–803. 10.1161/01.hyp.27.3.799 . Basile C, Lomonte C. When and how should an arteriovenous access be modified because of a high blood flow rate? Semin Dial. 2011;24:396–8. 10.1111/j.1525-139X.2011.00934.x . Iwashima Y, Horio T, Takami Y, Inenaga T, Kanemaru K, Kawano Y, Takishita S. Effects of the creation of arteriovenous fistula for hemodialysis on cardiac function and natriuretic peptide levels in CRF. Am J Kidney Dis. 2002;40:974–82. 10.1053/ajkd.2002.36330 . Seals DR, Hagberg JM, Spina RJ, Rogers MA, Schechtman KB, Ehsani AA. Enhanced left ventricular performance in endurance-trained older men. Volume 89. Circulation; 1994. pp. 198–205. 10.1161/01.cir.89.1.198 . MacRae JM, Levin A, Belenkie I. The cardiovascular effects of arteriovenous fistulas in chronic kidney disease: a cause for concern? Semin Dial. 2006;19:349–52. 10.1111/j.1525-139X.2006.00181.x . London GM. Left ventricular alterations and end-stage renal disease. Nephrol Dial Transpl. 2002;17(Suppl 1):29–36. 10.1093/ndt/17.suppl_1.29 . Begin V, Ethier J, Dumont M, Leblanc M, Levesque S. Prospective evaluation of the intra-access flow of recently created native arteriovenous fistulae. Am J Kidney Dis. 2002;40:1277–82. 10.1053/ajkd.2002.36890 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 04 Jul, 2025 Read the published version in BMC Cardiovascular Disorders → Version 1 posted Editorial decision: Revision requested 03 Feb, 2025 Editor assigned by journal 03 Feb, 2025 Submission checks completed at journal 31 Jan, 2025 First submitted to journal 24 Jan, 2025 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. 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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-5898012","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":409583348,"identity":"6481dac9-594b-4f36-980e-e9209626bb58","order_by":0,"name":"Gündüz Yümün","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA20lEQVRIiWNgGAWjYJACCSjN+ABI8PCRooXZAKSFjRQtbGAGQS3yEbkHb/P8OZy4dkbuscqvOXYybAzMDx/dwKPF8EZesjUPz+HEbTfy0m7LbksGOozN2DgHn5YZOWbSPBIgLTlmtyW3MQO18LBJE9ZiANFSLLmtnrAWeQmQlgSIFsaP2w4T1mLA88bYcs6BdONtZ94YSzNuO87DxkzAL/LtOYY33vyxlt12PMfw489t1fb87M0PH+O15QCYagaTzDxgEo9ysC0NYKoOTDL+IKB6FIyCUTAKRiYAAD/xRd06K8lCAAAAAElFTkSuQmCC","orcid":"","institution":"Çanakkale Onsekiz Mart University","correspondingAuthor":true,"prefix":"","firstName":"Gündüz","middleName":"","lastName":"Yümün","suffix":""},{"id":409583350,"identity":"5c6e146f-4264-423b-b753-7924076536b2","order_by":1,"name":"Mehmet Okan Donbaloğlu","email":"","orcid":"","institution":"Namık Kemal University","correspondingAuthor":false,"prefix":"","firstName":"Mehmet","middleName":"Okan","lastName":"Donbaloğlu","suffix":""},{"id":409583351,"identity":"b7ec564f-4247-4a96-b022-34354152cd9b","order_by":2,"name":"Selami Gürkan","email":"","orcid":"","institution":"Namık Kemal University","correspondingAuthor":false,"prefix":"","firstName":"Selami","middleName":"","lastName":"Gürkan","suffix":""},{"id":409583352,"identity":"524f2953-3c0d-40fb-8fee-a2cac2e4d30b","order_by":3,"name":"Özcan Gür","email":"","orcid":"","institution":"Namık Kemal University","correspondingAuthor":false,"prefix":"","firstName":"Özcan","middleName":"","lastName":"Gür","suffix":""},{"id":409583354,"identity":"b50a34e6-26fa-4231-99a9-2b2588951964","order_by":4,"name":"Aykut Demirkıran","email":"","orcid":"","institution":"Namık Kemal University","correspondingAuthor":false,"prefix":"","firstName":"Aykut","middleName":"","lastName":"Demirkıran","suffix":""}],"badges":[],"createdAt":"2025-01-24 19:53:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5898012/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5898012/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12872-025-04945-9","type":"published","date":"2025-07-04T15:57:59+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":75411097,"identity":"59681d07-5870-4ce9-a9fa-3632cffcc9dc","added_by":"auto","created_at":"2025-02-04 09:09:05","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":121895,"visible":true,"origin":"","legend":"\u003cp\u003eAccording to ROC analysis, the values of QA, CO, and CI vary depending on fistula localization, with CI exhibiting the highest sensitivity and specificity.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5898012/v1/a4e6a3bf9912beca684f4653.png"},{"id":75411234,"identity":"d37ce505-eb78-485d-be80-2512daa501d9","added_by":"auto","created_at":"2025-02-04 09:09:11","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":98870,"visible":true,"origin":"","legend":"\u003cp\u003ewhile the patient’s CPR % is \u0026gt;18.5%, 80% sensitivity, 75% specificity, and 82.7% probability are expected to be proximal to the patient's AVF location\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5898012/v1/c17d0c75706743e4b67fb130.png"},{"id":86179073,"identity":"5cc45eb4-3f46-4ffb-ba6e-7e017089329a","added_by":"auto","created_at":"2025-07-07 16:15:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":878076,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5898012/v1/d8746ecc-a985-45fe-9d62-9dba7b351bf5.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Do fistula flow rate and fistula location have any effects on heart failure developing in patients with arteriovenous fistula? ","fulltext":[{"header":"1. Intraduction","content":"\u003cp\u003eEnd-stage renal disease (ESRD) is a clinical condition that affects nearly all organ systems and can be life-threatening if untreated. Due to the insufficient number of kidney transplants, hemodialysis remains the most commonly used treatment method. Among vascular access options, arteriovenous fistula (AVF) is considered the safest and most durable, with the lowest rates of mortality and morbidity [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eEffective hemodialysis requires sufficient blood flow, durability, and easy, repeatable cannulation. AVFs are categorized by their location as proximal (e.g., brachiocephalic, brachiobasilic) or distal (e.g., snuffbox, radiocephalic). However, complications such as bleeding, infection, hematoma, thrombosis, stenosis, ischemic neuropathy, skin necrosis, steal syndrome, aneurysm/pseudoaneurysm, and high cardiac output failure (HCOF) are associated with AVFs.\u003c/p\u003e \u003cp\u003eFistula flow rate (Qa) plays a critical role in ensuring effective hemodialysis. While low Qa may indicate vascular access issues, high Qa is hypothesized to increase cardiac output (CO), potentially leading to HCOF [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Studies on long-term hemodialysis patients have introduced the concept of the Qa-to-CO ratio, known as cardiopulmonary recirculation (CPR) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe Vascular Access Society guidelines define high-flow AVF as one with a Qa of 1.0\u0026ndash;1.5 L/min and a CPR\u0026thinsp;\u0026gt;\u0026thinsp;0.20 [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Not all patients with high-flow AVFs develop heart failure. Some researchers suggest that HCOF, defined as symptomatic heart failure with an elevated cardiac index, is a rare complication of high-flow AVFs and usually occurs only in the presence of underlying heart disease [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. This study aims to investigate the relationship between fistula flow rates and heart failure symptoms, the correlation of Qa with CO, and the effects of fistula location on flow and cardiac output, and echocardiographic changes in patients with AVFs.\u003c/p\u003e"},{"header":"2. Material and Methods","content":"\u003cp\u003eThis study included 116 chronic hemodialysis patients treated and monitored at the Cardiovascular Surgery Clinic of Tekirdağ Namık Kemal University. Patients participated in a dialysis program for at least six months between January 2022 and August 2022. Among them, 56 had distal and 60 had proximal arteriovenous fistulas (AVFs). The study was conducted in compliance with the Declaration of Helsinki principles and approved by the ethics committee of Namık Kemal University.\u003c/p\u003e \u003cp\u003e \u003cb\u003eExclusion criteria\u003c/b\u003e included patients with Class IV heart failure (HF) per the New York Heart Association (NYHA) classification, a history of cardiac surgery, structural heart disease (e.g., valvular or congenital abnormalities) identified by echocardiography (ECHO), prior kidney transplantation, or graft AVFs other than native ones.\u003c/p\u003e \u003cp\u003eDemographic data and hemodialysis (HD) duration were recorded (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). AVF flow rate (Qa) was calculated using Doppler ultrasonography (DUS). Flow volume was determined based on AVF vessel diameter and mean flow rate using an algorithm embedded in the ultrasonography system [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Before transthoracic ECHO, HF symptoms were evaluated using the NYHA classification:\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic and clinical characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD / n(%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e56,3\u0026thinsp;\u0026plusmn;\u0026thinsp;10,03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e78 (%67,25)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38 (%32,75)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiabetes mellitus\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30 (%25,86)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody mass index (BMI) (kg/m2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23,5\u0026thinsp;\u0026plusmn;\u0026thinsp;3,58\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt; 18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (%3,46)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18\u0026ndash;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68 (%58,62)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u0026ndash;30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e42 (%36,20)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026gt; 30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (%1,72)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypertension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50 (%43.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAVF duration (months)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46,1\u0026thinsp;\u0026plusmn;\u0026thinsp;18,12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin (gr/dl)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11,25\u0026thinsp;\u0026plusmn;\u0026thinsp;1,82\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMyocardial infarction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (%1,7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCerebrovascular disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (%1,7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSystolic blood pressure (mm/hg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e127,1\u0026thinsp;\u0026plusmn;\u0026thinsp;21,7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiastolic blood pressure (mm/hg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e74,5\u0026thinsp;\u0026plusmn;\u0026thinsp;15,6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemodialysis time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;4 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16 (%14)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100 (%86)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;4 h\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFrequency of hemodialysis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2 times a week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (%5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 times a week\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e110 (%95)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003e\u003cem\u003e(Data Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD; Median(Min-Max); summarized as n(%)).\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eClass I\u003c/b\u003e: No limitation of physical activity.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eClass II\u003c/b\u003e: Slight limitation of physical activity (HF symptoms with ordinary activity but not at rest).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eClass III\u003c/b\u003e: Marked limitation of physical activity (HF symptoms with mild activity but not at rest).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eClass IV\u003c/b\u003e: Symptoms of HF at rest (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eClinical characteristics of patients according to the location of AVFs\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eProximal AVF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDistal AVF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;56)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58,3\u0026thinsp;\u0026plusmn;\u0026thinsp;9,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e53,9\u0026thinsp;\u0026plusmn;\u0026thinsp;9,6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,011\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24,5\u0026thinsp;\u0026plusmn;\u0026thinsp;3,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22,5\u0026thinsp;\u0026plusmn;\u0026thinsp;3,3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,002\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAV fistula duration\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e54(28\u0026ndash;82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34(16\u0026ndash;80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10,7\u0026thinsp;\u0026plusmn;\u0026thinsp;1,4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11,8\u0026thinsp;\u0026plusmn;\u0026thinsp;2,0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSystolic blood pressure (mm/hg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e127,2\u0026thinsp;\u0026plusmn;\u0026thinsp;22,3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e121,1\u0026thinsp;\u0026plusmn;\u0026thinsp;22,8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0,148\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiastolic blood pressure (mm/hg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e74,5\u0026thinsp;\u0026plusmn;\u0026thinsp;15,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e74,3\u0026thinsp;\u0026plusmn;\u0026thinsp;17,8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0,945\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003e(Data Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD; Summarized as Median(Min-Max)\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003ePatients were classified and recorded per the NYHA stages of HF at baseline and during follow-up. Class III was considered high cardiac output failure (HCOF) only if the cardiac index (CI) exceeded normal values (\u0026gt;\u0026thinsp;3.0 L/min/m\u0026sup2;) [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHeart failure symptoms included dyspnea, paroxysmal nocturnal dyspnea, orthopnea, and pulmonary and/or peripheral edema, assessed in conjunction with an elevated CI (\u0026gt;\u0026thinsp;3.0 L/min/m\u0026sup2;) [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Cardiac parameters, including left ventricular and left atrial functions, pulmonary arterial pressure, cardiac output (CO), ejection fraction (EF), and heart rate, were calculated via ECHO. Patients were grouped based on fistula location (Tables\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Assessments were performed within 24 hours post-dialysis, midweek.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDistribution of echocardiographic parameters according to groups\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eProximal AVF\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDistal AVF\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;56)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLV diastolic diameter (LVDD) (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e55,36\u0026thinsp;\u0026plusmn;\u0026thinsp;7,85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e50,63\u0026thinsp;\u0026plusmn;\u0026thinsp;4,74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLV systolic diameter (LVSD) (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e40,24\u0026thinsp;\u0026plusmn;\u0026thinsp;8,14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e35,84\u0026thinsp;\u0026plusmn;\u0026thinsp;5,46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiastolic IVS (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e11,85\u0026thinsp;\u0026plusmn;\u0026thinsp;1,55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e10,96\u0026thinsp;\u0026plusmn;\u0026thinsp;0,75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0,668\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiastolic posterior wall (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10,46\u0026thinsp;\u0026plusmn;\u0026thinsp;1.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11,65\u0026thinsp;\u0026plusmn;\u0026thinsp;1,67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0,842\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLV diastolic volume (LVDV) (ml)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e110\u0026thinsp;\u0026plusmn;\u0026thinsp;18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e70\u0026thinsp;\u0026plusmn;\u0026thinsp;16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLV systolic volume (LVSV) (ml)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e46\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e33\u0026thinsp;\u0026plusmn;\u0026thinsp;8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLA diameter (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e43,6\u0026thinsp;\u0026plusmn;\u0026thinsp;5,6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e39,2\u0026thinsp;\u0026plusmn;\u0026thinsp;4,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLA volume (ml/m2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e50\u0026thinsp;\u0026plusmn;\u0026thinsp;21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e37\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEF (modified Simpson\u0026rsquo;s\u003c/p\u003e \u003cp\u003emethod) (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e51,5\u0026thinsp;\u0026plusmn;\u0026thinsp;8,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e57,0\u0026thinsp;\u0026plusmn;\u0026thinsp;78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSystolic PAP (mmHg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e33,56\u0026thinsp;\u0026plusmn;\u0026thinsp;9,84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e28,75\u0026thinsp;\u0026plusmn;\u0026thinsp;9,66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLV mass index (g/m2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e158.93\u0026thinsp;\u0026plusmn;\u0026thinsp;80.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e108.56\u0026thinsp;\u0026plusmn;\u0026thinsp;43.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003e(Data are expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD or percentage. LV ; left ventricle, IVS; interventricular septum, LA; left atrium, PAP; pulmonary artery pressure, EF; ejection).\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCardiac characteristics of patients according to the location of AVFs\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eProximal AVF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDistal AVF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;56)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAVF blood flow rate (l/min) (Qa)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1,47 (0,57\u0026thinsp;\u0026minus;\u0026thinsp;2,9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0,85(0,52\u0026thinsp;\u0026minus;\u0026thinsp;2,3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEF (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51,5\u0026thinsp;\u0026plusmn;\u0026thinsp;8,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e57,0\u0026thinsp;\u0026plusmn;\u0026thinsp;78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCardiac output (l/min) (CO)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6,6\u0026thinsp;\u0026plusmn;\u0026thinsp;1,2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5,7\u0026thinsp;\u0026plusmn;\u0026thinsp;1,1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCardiac index (CI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5,4(3,1\u0026ndash;9,4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3,3(2,6\u0026ndash;8,9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCardiopulmonary recirculation (CPR, %)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24,6\u0026thinsp;\u0026plusmn;\u0026thinsp;6,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16,4\u0026thinsp;\u0026plusmn;\u0026thinsp;5,4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeart rate (atm/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e72,4\u0026thinsp;\u0026plusmn;\u0026thinsp;15,8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e72\u0026thinsp;\u0026plusmn;\u0026thinsp;13,8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0,866\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNYHA classification\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClass I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10(%16,6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e28(%50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClass II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34(%56,7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26(%46,4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClass III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16(%26,7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2(%3,6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e\u003cem\u003e(Data Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD; Median(Min-Max); summarized as n(%)).\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eStatistical Analysis\u003c/b\u003e:\u003c/p\u003e \u003cp\u003eSPSS 25.0 software was used for data analysis. Categorical variables were summarized as numbers and percentages, while continuous variables were expressed as means and standard deviations (or medians with minimum and maximum values, as necessary). Categorical variables were compared using the Chi-square or Fisher\u0026rsquo;s exact test. Continuous variables were analyzed with one-way ANOVA or Student\u0026rsquo;s t-test for parametric distributions and the Kruskal-Wallis or Mann-Whitney U test for non-parametric distributions. Receiver operating characteristic (ROC) curve analysis was used to calculate sensitivity and specificity for AVF location cut-off values. Statistical significance was set at P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 for all tests.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003eThe study included 116 patients, of whom 78 (67.25%) were male, and 38 (32.75%) were female. The mean age was 56.3\u0026thinsp;\u0026plusmn;\u0026thinsp;10.03 years. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e provides demographic and clinical characteristics of the patients. The mean body mass index (BMI) was 23.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.58, with 68 patients classified as normal weight (BMI 18\u0026ndash;25), 42 as overweight (BMI 25\u0026ndash;30), 4 as underweight (BMI\u0026thinsp;\u0026lt;\u0026thinsp;18), and 2 as obese (BMI\u0026thinsp;\u0026gt;\u0026thinsp;30). The mean hemoglobin (Hb) level was 11.25\u0026thinsp;\u0026plusmn;\u0026thinsp;1.82 g/dL.\u003c/p\u003e \u003cp\u003eAmong the patients, 30 (25.86%) had diabetes mellitus (DM), 50 (43.1%) had hypertension (HT), 2 (1.7%) had a history of myocardial infarction, and 2 (1.7%) had cerebrovascular disease. The mean systolic blood pressure was 127.1\u0026thinsp;\u0026plusmn;\u0026thinsp;21.7 mmHg, and the diastolic blood pressure was 74.5\u0026thinsp;\u0026plusmn;\u0026thinsp;15.6 mmHg.\u003c/p\u003e \u003cp\u003eMost patients (86%, 100 patients) underwent 4-hour dialysis sessions, with 14% (16 patients) undergoing sessions shorter than 4 hours. No patients had sessions longer than 4 hours. Additionally, 95% of patients (110) had dialysis three times a week, while 5% (6) had it twice weekly. The mean AVF duration was 46.1\u0026thinsp;\u0026plusmn;\u0026thinsp;18.12 months, and no patients exhibited cardiac arrhythmias.\u003c/p\u003e \u003cp\u003eClinical and Cardiac Characteristics: Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e summarizes patient characteristics by AVF location: According to this, 60 patients had proximal and 56 patients had distal AVF.\u003c/p\u003e \u003cp\u003eStatistically significant differences were observed between groups for age, BMI, AVF duration, and Hb values but not for blood pressure. Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows echocardiographic differences, including significant variations in left ventricular dimensions, volumes, and mass index, as well as left atrial parameters and pulmonary arterial pressure.\u003c/p\u003e \u003cp\u003eAVF Flow Rate and NYHA Classification: The mean Qa was 1.47 (0.57\u0026ndash;2.9) L/min in proximal fistulas and 0.85 (0.52\u0026ndash;2.3) L/min in distal fistulas (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001, Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Significant differences were also observed in CI, CO, and CPR values. NYHA classification revealed:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eProximal AVF Patients\u003c/b\u003e: 17% in Class I, 57% in Class II, and 26% in Class III.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eDistal AVF Patients\u003c/b\u003e: 50% in Class I, 46% in Class II, and 4% in Class III.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eA statistically significant higher proportion of proximal AVF patients were in NYHA Classes II and III. Among the Class III patients (n\u0026thinsp;=\u0026thinsp;18), all were classified as HCOF, with a CI of 6.87\u0026thinsp;\u0026plusmn;\u0026thinsp;1.65 L/min/m\u0026sup2;, Qa of 2.60 L/min, and CO of 8.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.69 L/min (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of cardiac parameter and AVF characteristics according to NYHA classification\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNYHA\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eClass I\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;38)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eClass II\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eClass III\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;18)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAVF flow rate (Qa) (l/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0,76(0,52\u0026thinsp;\u0026minus;\u0026thinsp;1,2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1,30(0,57\u0026thinsp;\u0026minus;\u0026thinsp;2,3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2,60(2,1\u0026ndash;2,9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEF (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58,10\u0026thinsp;\u0026plusmn;\u0026thinsp;7,90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e54,4\u0026thinsp;\u0026plusmn;\u0026thinsp;7,40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45,5\u0026thinsp;\u0026plusmn;\u0026thinsp;7,11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCardiac output (CO) (l/min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5,30\u0026thinsp;\u0026plusmn;\u0026thinsp;1,01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6,13\u0026thinsp;\u0026plusmn;\u0026thinsp;0,81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8,08\u0026thinsp;\u0026plusmn;\u0026thinsp;0,69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCardiac index (CI) (l/min/m2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.29\u0026thinsp;\u0026plusmn;\u0026thinsp;0.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4,8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6,87\u0026thinsp;\u0026plusmn;\u0026thinsp;1,65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAVF duration (months)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24(18\u0026ndash;36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e48(16\u0026ndash;80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54(28\u0026ndash;82)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCPR (Qa/CO) (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15,2\u0026thinsp;\u0026plusmn;\u0026thinsp;4,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19,2\u0026thinsp;\u0026plusmn;\u0026thinsp;6,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25,7\u0026thinsp;\u0026plusmn;\u0026thinsp;6,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e0,0001\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003e(Data Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD; Median(Min-Max); summarized as n(%)).\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe correlation between fistula locations and cardiac parameters was analyzed using ROC curve analysis. According to the ROC analysis, if the Qa value is \u0026gt;\u0026thinsp;1.15, the patient's AVF location is likely to be distal, with 64.3% sensitivity, 63.3% specificity, and 73.2% probability. Conversely, if the CPR % value is \u0026gt;\u0026thinsp;18.5, the AVF location is expected to be proximal, with 80% sensitivity, 75% specificity, and 82.7% probability. If the patient\u0026rsquo;s CO value is \u0026gt;\u0026thinsp;6.0, the AVF location is likely distal, with 67.9% sensitivity, 60% specificity, and 71.5% probability. Additionally, if the CI value is \u0026gt;\u0026thinsp;4.2, the AVF location is expected to be distal, with 75% sensitivity, 70% specificity, and 82.8% probability (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe presence of an arteriovenous fistula reduces systemic vascular resistance, leading to increased stroke volume and cardiac output (CO) to maintain blood pressure [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. This adaptation has been demonstrated by studies showing a significant increase in mean blood flow on the AVF side compared to the contralateral side [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. For instance, brachial arterial flow rates measured via Doppler ultrasound (DUS) increased markedly from baseline values after AVF creation, underscoring the substantial hemodynamic impact of AVFs. However, the correlation between AVF flow rate (Qa) and CO remains poorly understood, with limited data on their interdependence, and it is also estimated that high fistula flow rates increase CO and lead to HCOF.\u003c/p\u003e \u003cp\u003eSome studies suggest that high fistula flow rates (\u0026gt; 2.0 L/min) significantly increase CO, potentially resulting in high cardiac output failure (HCOF). Interestingly, while CO remains stable with AVF flow rates up to 2.0 L/min, further increases can overwhelm myocardial adaptation mechanisms, leading to cardiac dysfunction [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. This phenomenon is supported by findings indicating a higher prevalence of HCOF in patients with proximal AVFs compared to distal AVFs, as proximal AVFs tend to have higher Qa and CO values [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Our analysis showed a parallel increase in cardiac index (CI) values and a higher number of NYHA Class III patients in the proximal AVF group, suggesting a greater risk of HCOF development in this population. When Class II was analyzed, there was no significant difference between the number of patients with proximal AVFs and those with distal AVFs; however, there was a significant difference between the groups for Classes I and III.\u003c/p\u003e \u003cp\u003eThe findings of this study emphasize the importance of monitoring AVF flow and cardiac parameters to identify patients at risk for HCOF. According to the coralation analisys a Qa value \u0026gt; 1.15 L/min is associated with a distal AVF, while a CPR \u0026gt; 18.5% and CO \u0026gt; 6.0 L/min suggest a proximal AVF. Additionally, a CI value \u0026gt; 4.2 indicates a distal AVF. Furthermore, echocardiographic data from our study revealed significant cardiac changes after AVF creation, such as increased left ventricular end-diastolic diameter (LVEDD), fractional shortening, and cardiac output (CO). Additionally, when comparing the data obtained right before and 14 days after AVF creation, significant increases were observed in left ventricular end-diastolic diameter (+ 4%), fractional shortening (+ 8%), and CO (+ 15%) [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. In the long term, cardiac adaptation, characterized by left ventricular hypertrophy (LVH), occurs in hemodialysis patients due to volume overload [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. While these changes are initially adaptive, they may lead to long-term complications such as LVH, diastolic dysfunction, and ultimately heart failure in patients with high-flow AVFs.\u003c/p\u003e \u003cp\u003eThe pathophysiological mechanisms linking high-flow AVFs to heart failure include chronic volume overload and increased left ventricular diastolic volume (LVDV) [\u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e–\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Evidence from both short- and long-term studies suggests that LVH and elevated left atrial volume (LAV) contribute to diastolic pressure elevation, further exacerbating cardiac dysfunction. This progression underscores the importance of identifying patients predisposed to AVF-induced cardiac decompensation. Although some authors propose that AVF-related heart failure occurs only in those with pre-existing cardiac conditions, our findings indicate that high-flow AVFs alone can trigger HCOF in patients without prior heart disease. Risk factors for high-flow AVFs include male sex, upper-arm AVF placement, and prior fistula surgeries. Additionally, our study corroborates trends from the literature showing increased LVEDV and worsening cardiac parameters in patients with Qa \u0026gt; 2.0 L/min.\u003c/p\u003e \u003cp\u003eGiven these findings, regular monitoring of AVF flow using DUS and cardiac function using echocardiography (ECHO) is critical. Such surveillance can help mitigate the risk of HCOF, particularly in patients with proximal AVFs. Our study’s data align with previous research emphasizing the need for threshold values, such as Qa and CPR, to guide interventions. For instance, high CPR values (≥ 20%) and high flow rates (Qa ≥ 2.0 L/min) may serve as predictive markers for cardiac risk. However, further prospective studies are required to validate these thresholds and develop comprehensive guidelines for managing high-flow AVFs.\u003c/p\u003e \u003cp\u003e Limitations of our study include its retrospective, single-center design and the relatively small sample size (116 patients). Despite these limitations, our findings provide valuable insights into the hemodynamic and cardiac consequences of AVFs, particularly their potential to induce HCOF.\u003c/p\u003e "},{"header":"Conclisions","content":"\u003cp\u003eAlthough some studies suggest that AVF-induced cardiac decompensation may occur only in patients with underlying heart disease, our data show that one of the key findings being that the AVF Qa value is higher in proximal AVFs. Along with this result, the fact that cardiac index (CI), cardiac output (CO), and cardiac power reserve (CPR) values are also higher suggests that the risk of heart failure development is considerably greater in proximal AVFs compared to distal AVFs. Therefore, in patients with AVFs, it is crucial to monitor the fistula flow rates regularly using Doppler ultrasound (DUS) and to monitor patients for heart failure development with echocardiography (ECHO). While a high-flow AVF may be ideal for hemodialysis, but it should be remembered that any potential heart failure could be fatal unless properly monitored. Furthermore, guidelines may be developed to establish threshold Qa or CPR values for intervention to prevent high-flow AVF-induced high-output cardiac failure (HCOF). Additional prospective studies are needed to confirm whether the biologically plausible concept of high CPR (≥ 20%) and high flow rates (Qa ≥ 2.0 L/min) are indeed indicative of and related to increased cardiac risk.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflict of interest :\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe have no conflict of interest.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate: Yes (protocol: TNKU-2022.153.07.20)\u003c/p\u003e\n\u003cp\u003eConsent for publication: Yes\u003c/p\u003e\n\u003cp\u003eFunding: \u0026nbsp;No\u003c/p\u003e\n\u003cp\u003eAvailability of data and material: Yes\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRole of the Funding source\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was not supported by any organization.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eG.Y. and M.O.D. wrote the main manuscript text and E.F. prepared figures 1-3. G.Y., S.G., M.O.D., and \u0026Ouml;.G. performed fistula openings for the patients and recorded the patient characteristics.A.D. monitored the patients' heart insufficiency and systematically filed their records.All authors reviewed the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eGilmore J. KDOQI clinical practice guidelines and clinical practice recommendations\u0026ndash;2006 updates. Nephrol Nurs J. 2006;33:487\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEthier J, Dumont M, Beaulieu M, Girard R, Leblanc M. Relation between dialysis membrane characteristics and clinical outcomes. Nephrol Dial Transpl. 2008;23:3219\u0026ndash;26. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ndt/gfn228\u003c/span\u003e\u003cspan address=\"10.1093/ndt/gfn228\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBasile C, Lomonte C, Vernaglione L, Casucci F, Antonelli M. The relationship between the flow of arteriovenous fistula and cardiac output in haemodialysis patients. Nephrol Dial Transpl. 2008;23:282\u0026ndash;7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ndt/gfm586\u003c/span\u003e\u003cspan address=\"10.1093/ndt/gfm586\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePandeya S, Lindsay RM. The relationship between cardiac output and access flow during hemodialysis. ASAIO J. 1999;45:135\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00002480-199903000-00010\u003c/span\u003e\u003cspan address=\"10.1097/00002480-199903000-00010\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVascular Access Society. (2016) Guideline 20.3. Available at: www.vascularaccesssociety.org. Accessed June 29.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBeathard GA. (2017) Heart failure and hemodialysis arteriovenous fistulae. Available at: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.uptodate.com\u003c/span\u003e\u003cspan address=\"http://www.uptodate.com\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed May 22.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLondon GM. Left ventricular alterations and end-stage renal disease. Nephrol Dial Transpl. 2002;17(Suppl 1):29\u0026ndash;36. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ndt/17.suppl_1.29\u003c/span\u003e\u003cspan address=\"10.1093/ndt/17.suppl_1.29\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZamboli P, Fiorini F, D\u0026rsquo;Amelio A, Fatuzzo P, Marciano A. Color Doppler ultrasound and arteriovenous fistulas for hemodialysis. J Ultrasound. 2014;17:253\u0026ndash;63. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s40477-014-0102-4\u003c/span\u003e\u003cspan address=\"10.1007/s40477-014-0102-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMacRae JM, Pandeya S, Humen DP, Krivitski N, Lindsay RM. (2004) Arteriovenous fistula-associated high-output cardiac failure: a review of mechanisms. Am J Kidney Dis. 2004;43:e17-e22. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1053/j.ajkd.2003.12.036\u003c/span\u003e\u003cspan address=\"10.1053/j.ajkd.2003.12.036\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLondon GM, Guerin AP, Marchais SJ. Hemodynamic overload in end-stage renal disease patients. Semin Dial. 1999;12:77\u0026ndash;83. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1046/j.1525-139x.1999.00019.x\u003c/span\u003e\u003cspan address=\"10.1046/j.1525-139x.1999.00019.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLomonte C, Casucci F, Antonelli M, Vernaglione L. Is there a place for duplex screening of the brachial artery in the maturation of arteriovenous fistulas? Semin Dial. 2005;18:243\u0026ndash;6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1525-139X.2005.18209.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1525-139X.2005.18209.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGirerd X, London G, Boutouyrie P, Marnay-Gulatier E, Safar ME. Remodeling of the radial artery in response to a chronic increase in shear stress. Hypertension. 1996;27:799\u0026ndash;803. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1161/01.hyp.27.3.799\u003c/span\u003e\u003cspan address=\"10.1161/01.hyp.27.3.799\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBasile C, Lomonte C. When and how should an arteriovenous access be modified because of a high blood flow rate? Semin Dial. 2011;24:396\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1525-139X.2011.00934.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1525-139X.2011.00934.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIwashima Y, Horio T, Takami Y, Inenaga T, Kanemaru K, Kawano Y, Takishita S. Effects of the creation of arteriovenous fistula for hemodialysis on cardiac function and natriuretic peptide levels in CRF. Am J Kidney Dis. 2002;40:974\u0026ndash;82. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1053/ajkd.2002.36330\u003c/span\u003e\u003cspan address=\"10.1053/ajkd.2002.36330\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSeals DR, Hagberg JM, Spina RJ, Rogers MA, Schechtman KB, Ehsani AA. Enhanced left ventricular performance in endurance-trained older men. Volume 89. Circulation; 1994. pp. 198\u0026ndash;205. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1161/01.cir.89.1.198\u003c/span\u003e\u003cspan address=\"10.1161/01.cir.89.1.198\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMacRae JM, Levin A, Belenkie I. The cardiovascular effects of arteriovenous fistulas in chronic kidney disease: a cause for concern? Semin Dial. 2006;19:349\u0026ndash;52. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1525-139X.2006.00181.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1525-139X.2006.00181.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLondon GM. Left ventricular alterations and end-stage renal disease. Nephrol Dial Transpl. 2002;17(Suppl 1):29\u0026ndash;36. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ndt/17.suppl_1.29\u003c/span\u003e\u003cspan address=\"10.1093/ndt/17.suppl_1.29\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBegin V, Ethier J, Dumont M, Leblanc M, Levesque S. Prospective evaluation of the intra-access flow of recently created native arteriovenous fistulae. Am J Kidney Dis. 2002;40:1277\u0026ndash;82. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1053/ajkd.2002.36890\u003c/span\u003e\u003cspan address=\"10.1053/ajkd.2002.36890\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\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":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Hemodialysis, Fistula Location, Fistula Flow Rate, Heart Failure","lastPublishedDoi":"10.21203/rs.3.rs-5898012/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5898012/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThis study aims to explore the effects of arteriovenous fistula locations in the arm and fistula flow rates on the potential development of heart failure in patients with arteriovenous fistula (AVF).\u003c/p\u003e\u003ch2\u003eMaterial and Methods\u003c/h2\u003e \u003cp\u003eA total of 116 patients with AVF due to chronic kidney disease (CKD) were retrospectively reviewed between January 2022 and August 2022. Fifty-six patients with distal AVFs and 60 with proximal AVFs were compared in terms of demographic, clinical, and echocardiographic (ECHO) characteristics. Fistula flow rates were assessed using Doppler ultrasonography (DUS), while cardiac parameters were evaluated with ECHO. The correlation between fistula location and cardiac parameters was analyzed using ROC analysis.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe mean AVF blood flow rate (Qa) was 1.47 (0.57\u0026ndash;2.9) L/min for proximal fistulas and 0.85 (0.52\u0026ndash;2.3) L/min for distal fistulas. There were statistically significant differences between the proximal and distal AVF groups regarding cardiac index (CI), cardiac output (CO), and cardiopulmonary recirculation (CPR) values (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). According to the New York Heart Association (NYHA) classification, Class III can be categorized as high cardiac output failure (HCOF), as CI was calculated at 6.87\u0026thinsp;\u0026plusmn;\u0026thinsp;1.65 L/min/m\u0026sup2; (4.7\u0026ndash;9.4), Qa at 2.60 L/min (2.1\u0026ndash;2.9), and CO at 8.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.69 L/min.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eWhen heart failure develops in patients with AVF, underlying heart disease should not be the sole factor considered. Proximal high-flow AVFs, in particular, may contribute to heart failure development and warrant careful monitoring.\u003c/p\u003e","manuscriptTitle":"Do fistula flow rate and fistula location have any effects on heart failure developing in patients with arteriovenous fistula? 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