Venous Thromboembolic Events Following Revisional Gastric Bypass: An Analysis of the MBSAQIP Database From 2015 to 2019 Using Propensity Matching

Venous Thromboembolic Events Following Revisional Gastric Bypass: An Analysis of the MBSAQIP Database From 2015 to 2019 Using Propensity Matching | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Venous Thromboembolic Events Following Revisional Gastric Bypass: An Analysis of the MBSAQIP Database From 2015 to 2019 Using Propensity Matching Konstantinos P. Economopoulos, Nova Szoka, Shaina R. Eckhouse, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4554753/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Oct, 2024 Read the published version in Obesity Surgery → Version 1 posted 9 You are reading this latest preprint version Abstract Background Primary bariatric surgery is associated with moderate to high risk of venous thromboembolic events (VTE), however the risk for revisional surgery lacks granularity. Our primary objective was to define the risk of VTE following revisional Roux-en-Y gastric bypass (RYGB) compared to primary RYGB. Methods Adults who underwent primary or revision/conversion RYGB between January 1, 2015 and December 31, 2019 with a BMI ≥ 35 kg/m 2 were identified in a bariatric specific database. VTE was defined as pulmonary embolus and/or deep venous thrombosis. 30-day VTE and transfusion rates were compared between the two groups using propensity score matching of 3:1. Results Primary RYGB was performed in 197,186 (92.4%) patients compared to 16,144 (7.6%) in the revisional group. Patients in the revisional group had fewer comorbidities than those undergoing primary RYGB. In the matched cohort of 64,258 procedures, there were 48,116 (74.9%) primary RYGB cases compared to 16,142 (25.1%) RYGB revisions. The rate of VTE was similar in the revisional surgery group compared to the propensity matched primary RYGB group (0.4% vs. 0.3%, p > 0.580), however transfusion was more common in the revisional group (1.4% vs. 1.0%, p = 0.005). Revisional group had higher rates of readmission, reoperation, increased length of stay and operation length ≥ 180 minutes compared to matched primary RYGB group (p < 0 .001). Conclusions VTE rates for both primary and revisional RYGB are similar. Revisional RYGB cases impose increased risk of bleeding amongst other outcomes. Thus, identifying those at higher risk of complications is critical. Figures Figure 1 Key Points VTE rates for both primary and revisional RYGB are similar. VTE rates are significantly higher in certain patient cohorts. Revisional RYGB cases impose increased risk of bleeding. Introduction Venous thromboembolism (VTE) is defined as pulmonary embolism (PE) and/or deep venous thrombosis (DVT) and is associated with increased morbidity and mortality in the 30 days following bariatric surgery [ 1 , 11 ]. Additionally, VTE has been shown to be associated with a significant increase in readmissions and mortality [ 4 ]. Winegar et al. reported an overall VTE risk of 0.42%, which was greater in patients after Roux-en-Y gastric bypass (RYGB) [ 18 ]. Even though the reported mortality rate of PE is low, it remains one of the top causes of mortality following bariatric surgery [ 15 ]. Previously described risk factors for VTE after primary RYGB, can be broken down into three categories which include patient characteristics, intraoperative factors, and postoperative outcomes. Patient characteristics include age, gender, high body mass index (BMI), hypertension, congestive heart failure, history of myocardial infarction (MI), shortness of breath, oxygen dependence and paraplegia [ 2 , 7 , 10 ]. Intraoperative factors include length of procedure and type of primary bariatric surgery. Postoperative risk factors include length of stay and need for reoperation [ 2 , 7 , 10 ]. Taking these risk factors into consideration, it is important to try and mitigate them through preoperative counseling, perioperative prophylaxis, and postoperative monitoring. While there is an understanding of both the increased risk of VTE and risk factors for VTE after primary bariatric surgery, such risk after revisional procedures has not been elucidated when compared to primary RYGB procedures. Revisions following bariatric surgery are known to be higher risk for complications compared to primary bariatric surgery [ 19 ]. The objective of the present study is to examine the risk of VTE events following RYGB compared to revisional RYGB as described by the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database. Methods Data Source and Population After Institutional Review Board (IRB) approval, a retrospective review of prospectively collected data was conducted using the 2015 to 2019 MBSAQIP participant use datafile (PUF). This database includes demographics, comorbid conditions, intraoperative characteristics as well as 30-day outcomes after bariatric surgery from 868 participating sites and 966,646 cases collected from January 1, 2015, to December 31, 2019. The intervention data files are similarly linked with 14,240 events and information regarding days from operation, intervention type, and indication for interventions. Subjects were included if they were ≥ 18 years old, underwent minimally invasive RYGB by a General or Metabolic and Bariatric Surgeon using Current Procedural Technology (CPT) codes (43644, 43645), had a BMI ranging from 35 kg/m 2 to 120 kg/m 2 , and were discharged in less than 31 days from surgery. The revisional RYGB group consisted of subjects who underwent revision or conversion RYGB while the others were in the primary RYGB group ( Fig. 1 ) . The approaches utilized by surgeons included conventional laparoscopic, laparoscopic-assisted, and robotic-assisted cases. Paraesophageal hernia repair (CPT 43281, 43282), liver biopsy (CPT 47001, 47379), cholecystectomy (CPT 47562, 47563), and adhesiolysis (CPT 44180) were included in other procedures 1, 2 and 3. Patients were excluded from the cohort (746,281) if they underwent procedures other than RYGB, procedures that were performed open, hand assisted, natural orifice transluminal endoscopic surgery (NOTES), or single incision approach. Emergency cases and investigational procedures were also excluded. Single stage band revisions (CPT 43771, 43772, 43773, 43774) listed in other procedure 1, 2, and 3 and implausible operative length < 20 minutes resulted in exclusion of another 7,039 procedures. Variable definitions The MBSAQIP datafile definitions for revision and conversion were used. VTE included PE and/or DVT. PE was defined as a new blood clot in the pulmonary artery confirmed by radiographic imaging or autopsy. DVT was a new blood clot or venous thrombus requiring intervention. Significant bleeding was defined as such an event that needed transfusion of red blood cells within 72 hours from the procedure and/or required an unplanned endoscopic intervention or reoperation to control the bleeding source. Data Collection The demographics of interest included sex, age, race, ethnicity, and BMI. Pre-operative comorbid conditions included diabetes mellitus, gastroesophageal reflux disease, history of MI, previous percutaneous coronary intervention, previous cardiac surgery, hyperlipidemia, venous stasis, hypertension requiring medication, renal insufficiency, dialysis, current smoker, chronic obstructive pulmonary disease, oxygen dependence, sleep apnea, functional health status, history of PE, history of DVT, inferior vena cava (IVC) filter, therapeutic anticoagulation, chronic steroids, hematocrit value, and number of packed red blood cells. Intraoperative characteristics included operative year, American Society of Anesthesiologists classification (ASA), first assistant training level, surgical approach, operative length, other procedures, drain placed and anastomosis checked. Postoperative variables assessed were swallow study, length of stay (LOS), VTE, anticoagulation initiated, transfusion 72 hours from surgery, acute renal failure, cardiac arrest, stroke, myocardial infarction, progressive renal failure, unplanned Intensive Care Unit admission, drain present at 30 days, death, discharge destination, readmission, reoperation, intervention, emergency department visit, dehydration treatments, and cause of death. Race was reported as White, Black, and Other/unknown. VTE groups were PE, DVT, both (PE and DVT), and none. Discharge destinations were grouped by home (home, facility which was home), skilled (rehab, skilled care, not home, separate acute care), and unskilled (unskilled facility not home, unknown) facility. Age, BMI, preoperative hematocrit level, operative length, number units red blood cells transfused, number of dehydration treatments, number of emergency department visits, days to death were analyzed both as continuous and categorical variables. Primary and Secondary Outcomes The primary outcome of interest was rate of VTE in patients undergoing primary versus revisional RYGB. The secondary outcome was bleeding requiring blood transfusion. Additional outcomes captured included anticoagulation initiation, readmission, reoperation, intervention, treatment for dehydration, emergency department visit, LOS, length of operation, days to death and most likely cause of death. Statistical Analysis The cohort with primary RYGB was compared to the group with revisional RYGB surgery. For each analysis, continuous variables were compared using Mann-Whitney U tests and reported as means ± standard deviation (SD). Categorical variables were compared using Fisher exact tests and reported as counts and percentages. Propensity score matched analysis was performed to address intergroup bias. Propensity matching was performed with race, ethnicity, BMI ≥ 50kg/m 2 (binary variable), gastroesophageal reflux disease, diabetes, hypertension, hyperlipidemia, obstructive sleep apnea, smoking, and previous percutaneous coronary intervention based on previous publications on revisional RYGB [ 19 ]. Patients who underwent primary RYGB and those who had revisional RYGB were matched 3:1 based on propensity score. Given the rarity of the event and to further reduce the variance of the treatment effects, a 3:1 instead of a 1:1 matching was selected. Matching was performed with the MatchIt package in R 4.03 (R Core Team, Vienna, Austria) using nearest-neighbor matching with a caliper of 0.25. Standardized difference < 0.10 was considered adequate. A covariate-adjusted analysis of VTE was performed with predetermined factors with clinical relevance, which included were age, sex, BMI ≥ 50kg/m 2 , race, ethnicity, ASA class, hypertension, smoking status, dialysis, venous stasis, history of MI, oxygen dependent status, chronic steroids use, history of DVT, history of PE, IVC filter, mobility status, therapeutic anticoagulation, revisional surgery, presence of paraesophageal hernia, and operation length ≥ 180 minutes. The transfusion covariate-adjusted model included age, sex, BMI ≥ 50kg/m 2 , racial group, ethnicity, ASA class, hypertension, smoking status, dialysis, venous stasis, history of MI, chronic steroids use, therapeutic anticoagulation, revisional surgery, presence of paraesophageal hernia, drain placed at time of surgery, and operation length ≥ 180 minutes. Results Primary vs revisional RYGB - Unmatched groups The total number of patients in our study population was 213,330 with 197,186 (92.4%) patients in the primary and 16,144 (7.6%) patients in the revisional RYGB groups ( Supplemental Table 1 ). Of the primary RYGB group, 19.5% were male and the mean age was 45.1 ± 11.8 years. In the revisional RYGB group, 12.0% were male and the mean age was 47.4 ± 10.9 years. Mean BMI for the primary and revisional RYGB groups were 46.3 ± 7.7 kg/m 2 and 44.2 ± 7.1 kg/m 2 , respectively. In the primary RYGB group, 90.9% of cases were laparoscopic and 9.1% were robotic . In the revisional RYGB group, 87.6% of the cases were laparoscopic and 12.4% were robotic. The operative duration was 121.2 ± 54.4 minutes and 153.2 ± 74 minutes for the primary and revisional RYGB groups respectively (Supplemental Table 2). Overall complication rates were low for primary and revisional RYGB groups: MI 0.0% vs 0.1%, cardiac arrest 0.1% vs 0.1%, mortality 0.1% vs 0.2%, and reoperation 2.2% vs 3.7%. Additionally, patients in the primary RYGB group less frequently had LOS > 3 days at 5.1% compared to revisional RYGB at 8.5% (p<0.001). Emergency Department visits, readmissions, reoperations, interventions and drain present at 30 days were higher in the revisional RYGB group. Thirty-day VTE rates were higher for primary RYGB when compared to revisional RYGB group while bleeding rates were elevated in patients in the revisional RYGB group ( Supplemental Table 3 ). Primary vs revisional RYGB - Matched groups After propensity score matching, the sample was reduced to 64,258, with 74.9% (n = 48,116) in the primary RYGB group and 25.1% (n = 16,142) in the revisional group, making for a 2.98:1 ratio of primary to revisional RYGB patients ( Table 1 ). Covariates were balanced across surgery groups with the exceptions of BMI (primary RYGB had a mean BMI of 45.0 ± 7.0 kg/m 2 versus revisional RYGB had a mean BMI of 44.2 ± 7.1 kg/m 2 , Table 1) , chronic obstructive pulmonary disease (1.8% in primary versus 1.4% in revisional, Table 1 ), and history of DVT (1.9% in primary versus 2.6% in revisional, Table 1 ). Mean standardized difference in covariates used in the propensity model, across surgery types, was 0.033, meaning that adequate balance was achieved. Patients in the revisional RYGB surgery group had a higher proportion of readmission, reoperation and intervention 30 days post-surgery when compared to patients in the primary RYGB group (p 3 days (p<0.001) were observed in the revisional RYGB group ( Table 2 ). Operative times of greater than 180 minutes were more frequent in the revisional RYGB group compared to the primary RYGB group (28.6% to 13.1%, p<0.001, Table 2 ). On subgroup analysis of patients who died within 30 days of operation (n=61), there was no difference when comparing the revisional RYGB cohort to the primary RYGB cohort in days to death (p=0.54, Table 2 ) or cause of death (p=0.550, Table 2 ). PE was the most common cause of death in both groups (29.4% in the revisional RYGB vs. 18.6% in the primary RYGB group, p=0.550). Primary Endpoint In an unadjusted logistic regression with VTE as the outcome and surgery type as the sole explanatory variable, the estimated odds ratio (OR) was 1.22 [95% confidence interval (CI) (0.91-1.63)], implying that revisional surgery did not have a statistically significant role in changing the odds of VTE. In an adjusted version of the same regression, the estimated odds ratio was 1.09 [95% CI (0.81-1.47)], again concluding that revisional RYGB surgery did not increase the odds of VTE compared to primary RYGB ( Table 3 ).In the same analysis, Black patients had increased odds of VTE [OR 1.7, 95% CI (1.27-2.29)] compared to Other and White patients. The odds of VTE were higher in the following groups: group that used chronic steroids relative to the group that did not [OR 1.99 95% CI (1.01-3.91); p=0.046], patients with history of MI [OR 2.83 95% CI (1.4-5.71); p=0.004] and finally, patients with history of DVT [OR 3.01 95% CI (1.66-5.46); p 50 kg/m 2 were associated with decreased odds of blood transfusion, while limited mobility, use of therapeutic anticoagulation, hypertension, smoking and having a drain placed at the time of surgery were risk factors for increased odds of transfusion ( Table 4 ). Discussion The risk of VTE following revisional RYGB surgery is not well described or understood, thus this study used a bariatric specific datafile to further understand the risk in comparison to primary RYGB. The key findings of the present study are three-fold. First, the rate of VTE was low after both primary and revisional RYGB. However, despite the low VTE rates, PE remains the most commonly identified cause of postoperative mortality after bariatric surgery. Second, VTE rates were greater for particular cohorts of patients, thus raising concerns about additional factors including social determinants of health playing a significant role. Lastly, patients undergoing revisional RYGB had higher rates of bleeding and other complications including readmissions, reoperations and other interventions. In our study, the 30-day rate of VTE was impressively low for both primary and revisional groups. The rate of PE was 0.1% after primary RYGB and 0.2% after revisional RYGB. This is generally lower than the wide range of previously reported PE rates after bariatric surgery, from 0–6.4% [ 1 ]. Furthermore, the rate of DVT in our study was 0.1% in both groups and is lower than previously reported DVT rates ranging up to 5.4% following bariatric surgery [ 1 ]. Of note, rates of 30-day VTE at 0.3% for patients undergoing primary or revisional RYGB [ 9 , 13 ]. Despite the low rates of VTE following RYGB, it still remains a point of potential post-operative concern because PE is the leading cause of death after bariatric surgery. The focus of VTE treatment is complex and includes weight the goals of treatment with the risk of a complication from bleeding. Administering chemoprophylaxis has been the mainstay approach to decrease the rates of VTE. While the data on chemoprophylaxis is extensive and compares type, dose, frequency, and potential therapy extension, it lacks standardization for bariatric surgery patients. Additionally, patients following bariatric surgery are a unique cohort with unique pre-operative and intraoperative characteristics. Interestingly, the VTE rates were lower for patients in this study when compared to patients with gastrointestinal cancer who underwent surgery (2.8%-8.9%) [ 12 ] and when compared to those who underwent laparoscopic cholecystectomy for gallbladder disease (0.4%) [ 17 ]. Furthermore, given that the known VTE risk factors such as reoperation, LOS ≥ 3 days and operations ≥ 180 minutes in length were all more common in the revisional RYGB, it is surprising that VTE rates were similar after matching. While surprising, it is similar to other literature reports describing revisional RYGB risks [ 3 ]. Overall, it is important to understand the unique characteristics and potential intraoperative challenges faced by patients who have revisional RYGB to properly follow risk for VTE post-operatively. PE was the most commonly identified cause of death for both groups 30 days from surgery. Thus, it is prudent to maintain a high index of suspicion for VTE in patients undergoing primary and revisional RYGB. Several guidelines have been established to help identify those at increased VTE risk. In 2007, the SAGES guidelines on DVT prophylaxis during laparoscopic surgery were released [ 16 ] and were subsequently updated by the American College of Chest Physicians (ACCP) [ 8 ]. Additionally, two post-operative VTE risk calculators currently exist for primary bariatric surgery [ 2 , 7 ]. Both risk calculators utilize similar risk factors that included age, male gender, higher BMI, longer operative times [ 2 , 7 ]. In addition to these previously established risk factors for VTE, we identified several other comorbidities that were associated with higher VTE rates following revisional RYGB, including decreased functional ability, use of immunosuppressants, and cardiopulmonary status. Recommendations were made by Aminian et al. to initiate peri-operative chemoprophylaxis for all patients undergoing bariatric surgery, extend post discharge prophylaxis for two weeks in high-risk patients, and extend post-discharge prophylaxis for four weeks in the very high-risk group [ 2 ]. Since the average BMI for revisional RYGB patients is lower in our study, the extended chemoprophylaxis dose and duration of treatment may need to be adjusted further to prevent bleeding events. While several risk factors are accounted for in the Cleveland Clinic risk calculator, an individualized approach that looks at history of VTE, cancer, concurrent estrogen therapy, cerebrovascular accident, and additional critical metrics should be performed at bedside to tailor VTE prophylaxis to the patient [ 2 , 15 ]. Therefore, these results could suggest that patients undergoing revisional RYGB have unique challenges where peri-operative and extended chemoprophylaxis may require a different risk-stratification and analysis. One of the additional findings in our study was that particular cohorts of patients were at increased risk for VTE. Black race, chronic steroid users, and those with history of MI were all at increased risk for VTE and should be included in the high risk for VTE category. As mentioned earlier, Black patients had higher odds of VTE, and this finding may present an area of potential disparities in healthcare. Black patients undergoing bariatric surgery have been reported to have increased IVC placement and this could be a representation of lower access to care [ 14 ]. IVC filter placement is no longer standard of care for patients undergoing bariatric surgery preoperatively. Other social determinants of health were not assessed by this study but may very well be related to poor outcomes, increased VTE rates and suboptimal treatment strategies. Race, ethnicity, socioeconomic status should be included in future analyses to determine whether this represents a disparity in clinical care and outcomes. Our study also looked at the bleeding rates post-operatively. Patients undergoing revisional RYGB were more like to require a transfusion within the first 72 hours after surgery compared to primary RYGB. Higher rates for intraoperative transfusions were previously reported for patients undergoing revisional bariatric surgery (7% vs 0%, p < 0.001) [ 19 ]. In our study, male gender, BMI ≥ 50 kg/m 2 , limited mobility, use of therapeutic anticoagulation, drain placement at the time of surgery, smoking, and hypertension were all associated with increased risk of needing a transfusion. More complications and increased healthcare utilization was identified in patients undergoing revisional surgery compared to primary RYGB operation. Consistent with prior studies, readmission, reoperation, intervention, emergency room visits, and LOS ≥ 3 days were all significantly higher in the revisional RYGB group as well [ 2 ]. Identifying the risk factors for readmission to minimize the risk of such an event is paramount as decreasing readmissions significantly decreased utilization of healthcare resources and was associated with significant cost-savings [ 5 ]. Additionally, revisional RYGB surgery had longer operative times and higher utilization of robotic platform. The increased use of the robot for revisional bariatric surgery echoes the existing literature [ 8 ]. These finding related to revisional RYGB surgery are important given the ongoing trends in bariatric surgery. The total number of revisional RYGB procedures almost tripled from 2015 to 2019 while primary RYGB procedures remain relatively stable [ 6 ]. As the frequency of revisional RYGB cases increases, we need to consider whether the use of previously reported VTE risk calculators is applicable to those patients or whether revisional bariatric patients have a unique VTE risk profile requiring new guidelines and different risk calculators. Therefore, identifying VTE risk factors that would warrant extended chemoprophylaxis while attempting to balance the risk of postoperative bleeding should be considered on individual basis and should be elucidated in future prospective studies. Limitations There are several limitations to this study. First, there are limitations that are related to the data available in the MBSAQIP datafile. This dataset does not provide information on several factors including details of perioperative and post-discharge anticoagulation. While an area of focus for weight-based chemoprophylaxis, the type, dose, and length of anticoagulant use were not included in the current data files. Additionally, history of cancer, a known risk factor for VTE, is not included in the MBSAQIP datafile. Furthermore, the MBSAQIP data file does not include a follow up period beyond 30 days and thus dose not capture late VTE or death. Second, there are multiple CPT codes used for revisional surgery, including 43659, an unlisted procedure on the stomach; this may have resulted in omission of some of the revisional cases in our analysis. We used a 3:1 propensity to address treatment (surgery) selection bias and the fact that the primary surgery group and the revisional surgery group in the original sub-population differed widely on a series of baseline covariates. Propensity score matching was chosen as a method of addressing selection bias and balancing baseline covariates between the two groups, Given the rarity of the outcome event (VTE) in our sample, a ratio of 3:1 was chosen, as opposed to a 1:1 match, to increase the sample size and efficiency, although we recognize that there is a possibility that this will introduce added bias to our estimates. We also compared our matching scheme with other schemes using from 1:1 to 1:5 matching ratios and either our original .25 caliper or the optimal caliper of .2 times the standard deviation of the logit of the propensity score. Our scheme has the lowest mean standardized difference (tied with the 1:3 scheme with the optimal caliper) and is only slightly behind the 1:2 scheme with the optimal caliper in terms of median standardized difference. Indicating that the match was effective at balancing the covariates across surgery groups as seen in the demographic and clinical characteristics table post-matching. Lastly, as with any retrospective study, there could be inherent biases including selection bias and bias from inaccurately recorded or missing data. Despite these limitations, the current study provides a comparison of the incidence of VTE between primary and revisional RYGB patients utilizing a large, propensity-matched, sample size. Conclusion Revisional bariatric surgery has been increasing over the past few years. Given that VTE remains a significant source of morbidity and mortality in the bariatric surgery population, it is paramount to look at the relationship between revisional surgery and VTE. While our study demonstrates no increased risk of VTE in revisional RYGB cases when compared to primary RYGB cases, it does show that VTE rates are significantly higher in certain patient cohorts. Some of these cohorts are identified with current VTE prophylaxis risk calculators (such as venous stasis, history of VTE, longer operative times, older age, and higher BMI); however, others are not, including Black race, need for dialysis, history of MI and chronic steroid use. Therefore, it is paramount to have future studies looking at revisional surgeries and identifying other potential variables that may affect VTE rates to have a standardized extended VTE prophylaxis protocol. Declarations Funding: There was no funding for this study. Author Contribution Konstantinos Economopoulos and Keri Seymour designed the work; Konstantinos Economopoulos, Nova Szoka, Shaina Eckhouse, Maryna Chumakova-Orin, Keri Seymour helped with the acquisition of data, Maragatha Kuchibhatla, James Merchant, Keri Seymour helped with analysis of data, Konstantinos Economopoulos, Nova Szoka, Shaina Eckhouse, Maryna Chumakova-Orin, Maragatha Kuchibhatla, James Merchant, Keri Seymour helped with interpretation of data and reviewed and approved the manuscript. Data Availability Data is provided within the manuscript and supplementary information files. References American Society for M, Bariatric Surgery Clinical Issues C. ASMBS updated position statement on prophylactic measures to reduce the risk of venous thromboembolism in bariatric surgery patients. Surg Obes Relat Dis. 2013 Jul-Aug;9(4):493–7. Aminian A, Andalib A, Khorgami Z, Cetin D, Burguera B, Bartholomew J, et al. 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Surg Endosc. 2015;29(6):1316–20. Tables Tables 1-4 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files SupplementalTablesAnonymous.docx TablesAnonymous.docx Cite Share Download PDF Status: Published Journal Publication published 01 Oct, 2024 Read the published version in Obesity Surgery → Version 1 posted Editorial decision: Revision requested 20 Jul, 2024 Reviews received at journal 13 Jul, 2024 Reviews received at journal 07 Jul, 2024 Reviewers agreed at journal 05 Jul, 2024 Reviewers agreed at journal 04 Jul, 2024 Reviewers invited by journal 02 Jul, 2024 Editor assigned by journal 02 Jul, 2024 Submission checks completed at journal 16 Jun, 2024 First submitted to journal 09 Jun, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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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-4554753","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":315174365,"identity":"144f85ce-fadc-4f6c-8359-6d95cf2811a4","order_by":0,"name":"Konstantinos P. Economopoulos","email":"","orcid":"","institution":"Duke University","correspondingAuthor":false,"prefix":"","firstName":"Konstantinos","middleName":"P.","lastName":"Economopoulos","suffix":""},{"id":315174369,"identity":"1b8ba1d5-b0a1-409f-8363-ee5cb8202279","order_by":1,"name":"Nova Szoka","email":"","orcid":"","institution":"West Virginia University","correspondingAuthor":false,"prefix":"","firstName":"Nova","middleName":"","lastName":"Szoka","suffix":""},{"id":315174371,"identity":"ab614829-4627-4fbc-8e3d-50504a8477d0","order_by":2,"name":"Shaina R. Eckhouse","email":"","orcid":"","institution":"Duke University","correspondingAuthor":false,"prefix":"","firstName":"Shaina","middleName":"R.","lastName":"Eckhouse","suffix":""},{"id":315174372,"identity":"645cfe9a-98c5-4933-a6b8-fb4db72c80a2","order_by":3,"name":"Maryna Chumakova-Orin","email":"","orcid":"","institution":"East Carolina University","correspondingAuthor":false,"prefix":"","firstName":"Maryna","middleName":"","lastName":"Chumakova-Orin","suffix":""},{"id":315174373,"identity":"5f5a6bee-5f04-420c-be55-abe22caa46c0","order_by":4,"name":"Maragatha Kuchibhatla","email":"","orcid":"","institution":"Duke University","correspondingAuthor":false,"prefix":"","firstName":"Maragatha","middleName":"","lastName":"Kuchibhatla","suffix":""},{"id":315174374,"identity":"6d4f259d-7ee4-4458-bc68-6f5be37c8c5a","order_by":5,"name":"James Merchant","email":"","orcid":"","institution":"University of Iowa","correspondingAuthor":false,"prefix":"","firstName":"James","middleName":"","lastName":"Merchant","suffix":""},{"id":315174375,"identity":"81a70d3b-ab17-4dcb-81d4-756733d3df23","order_by":6,"name":"Keri A. Seymour","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7ElEQVRIiWNgGAWjYBACCSA+AOd9YGMwgIkSp4VxBrFa4ICZhxgtku29Dw8w/LFJXNveY/bZpuywMT8D88HbPHi0SPMcNzjA2JaWuO3MGePZOecOm0k2sCVb49MiJ5HGcICx4XDiths5xsy5bYdtDA7wmEnj1SL/DOj9P/8hWiyBWuwP8H/Dq0Vagg2ohe0ARAtj22EzAwYeNrxaJHuADktsSzbeduZYMWPPuXRjicNsxpZz8GiROH6M+cOHP3ay2443b2b4UWZt2N/e/PDGGzxawCCBgcGxAc5jJqQcCuyJVDcKRsEoGAUjEQAA8A5KvJFiMecAAAAASUVORK5CYII=","orcid":"","institution":"Duke University","correspondingAuthor":true,"prefix":"","firstName":"Keri","middleName":"A.","lastName":"Seymour","suffix":""}],"badges":[],"createdAt":"2024-06-09 18:23:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4554753/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4554753/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11695-024-07511-y","type":"published","date":"2024-10-01T15:56:52+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":60339353,"identity":"43cba4e2-204b-4201-8f01-48fcbf5ef6c8","added_by":"auto","created_at":"2024-07-15 17:57:10","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":548654,"visible":true,"origin":"","legend":"\u003cp\u003eFlow diagram of cohort creation\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAbbreviations:\u003c/strong\u003e MBSAQIP = Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program, BMI = body mass index, RYGB =Roux-en-Y gastric bypass, N.O.T.E.S.= natural orifice translumenal endoluminal surgery, CPT = current procedural terminology, OTHCPT = CPT code listed in addition to the main bariatric surgery performed. CPT 43771, 43772, 43773, 43774 represent single stage adjustable gastric band or port removal.\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4554753/v1/2de6cd129864b61892c66d43.jpg"},{"id":66096647,"identity":"23637768-c0c1-49cf-a2c8-96b543dec810","added_by":"auto","created_at":"2024-10-07 16:04:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":956836,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4554753/v1/a4001804-9ea6-4950-82e1-f2fb9031d428.pdf"},{"id":60338810,"identity":"3981ef80-474c-4b26-af57-6f1f1b1d489a","added_by":"auto","created_at":"2024-07-15 17:49:10","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":43478,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalTablesAnonymous.docx","url":"https://assets-eu.researchsquare.com/files/rs-4554753/v1/32ce35e7b0734024824671f8.docx"},{"id":60338811,"identity":"c123bf6e-c724-438f-a19a-68b95f677c1c","added_by":"auto","created_at":"2024-07-15 17:49:10","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":36849,"visible":true,"origin":"","legend":"","description":"","filename":"TablesAnonymous.docx","url":"https://assets-eu.researchsquare.com/files/rs-4554753/v1/4c64158e3d77099ee4210423.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Venous Thromboembolic Events Following Revisional Gastric Bypass: An Analysis of the MBSAQIP Database From 2015 to 2019 Using Propensity Matching","fulltext":[{"header":"Key Points","content":"\u003cul\u003e\n \u003cli\u003eVTE rates for both primary and revisional RYGB are similar.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eVTE rates are significantly higher in certain patient cohorts.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eRevisional RYGB cases impose increased risk of bleeding.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"Introduction","content":"\u003cp\u003eVenous thromboembolism (VTE) is defined as pulmonary embolism (PE) and/or deep venous thrombosis (DVT) and is associated with increased morbidity and mortality in the 30 days following bariatric surgery [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Additionally, VTE has been shown to be associated with a significant increase in readmissions and mortality [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Winegar et al. reported an overall VTE risk of 0.42%, which was greater in patients after Roux-en-Y gastric bypass (RYGB) [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Even though the reported mortality rate of PE is low, it remains one of the top causes of mortality following bariatric surgery [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePreviously described risk factors for VTE after primary RYGB, can be broken down into three categories which include patient characteristics, intraoperative factors, and postoperative outcomes. Patient characteristics include age, gender, high body mass index (BMI), hypertension, congestive heart failure, history of myocardial infarction (MI), shortness of breath, oxygen dependence and paraplegia [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Intraoperative factors include length of procedure and type of primary bariatric surgery. Postoperative risk factors include length of stay and need for reoperation [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Taking these risk factors into consideration, it is important to try and mitigate them through preoperative counseling, perioperative prophylaxis, and postoperative monitoring.\u003c/p\u003e \u003cp\u003eWhile there is an understanding of both the increased risk of VTE and risk factors for VTE after primary bariatric surgery, such risk after revisional procedures has not been elucidated when compared to primary RYGB procedures. Revisions following bariatric surgery are known to be higher risk for complications compared to primary bariatric surgery [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The objective of the present study is to examine the risk of VTE events following RYGB compared to revisional RYGB as described by the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eData Source and Population\u003c/h2\u003e \u003cp\u003e After Institutional Review Board (IRB) approval, a retrospective review of prospectively collected data was conducted using the 2015 to 2019 MBSAQIP participant use datafile (PUF). This database includes demographics, comorbid conditions, intraoperative characteristics as well as 30-day outcomes after bariatric surgery from 868 participating sites and 966,646 cases collected from January 1, 2015, to December 31, 2019. The intervention data files are similarly linked with 14,240 events and information regarding days from operation, intervention type, and indication for interventions.\u003c/p\u003e \u003cp\u003eSubjects were included if they were \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;18 years old, underwent minimally invasive RYGB by a General or Metabolic and Bariatric Surgeon using Current Procedural Technology (CPT) codes (43644, 43645), had a BMI ranging from 35 kg/m\u003csup\u003e2\u003c/sup\u003e to 120 kg/m\u003csup\u003e2\u003c/sup\u003e, and were discharged in less than 31 days from surgery. The revisional RYGB group consisted of subjects who underwent revision or conversion RYGB while the others were in the primary RYGB group \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. The approaches utilized by surgeons included conventional laparoscopic, laparoscopic-assisted, and robotic-assisted cases. Paraesophageal hernia repair (CPT 43281, 43282), liver biopsy (CPT 47001, 47379), cholecystectomy (CPT 47562, 47563), and adhesiolysis (CPT 44180) were included in other procedures 1, 2 and 3.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePatients were excluded from the cohort (746,281) if they underwent procedures other than RYGB, procedures that were performed open, hand assisted, natural orifice transluminal endoscopic surgery (NOTES), or single incision approach. Emergency cases and investigational procedures were also excluded. Single stage band revisions (CPT 43771, 43772, 43773, 43774) listed in other procedure 1, 2, and 3 and implausible operative length\u0026thinsp;\u0026lt;\u0026thinsp;20 minutes resulted in exclusion of another 7,039 procedures.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eVariable definitions\u003c/h2\u003e \u003cp\u003eThe MBSAQIP datafile definitions for revision and conversion were used. VTE included PE and/or DVT. PE was defined as a new blood clot in the pulmonary artery confirmed by radiographic imaging or autopsy. DVT was a new blood clot or venous thrombus requiring intervention. Significant bleeding was defined as such an event that needed transfusion of red blood cells within 72 hours from the procedure and/or required an unplanned endoscopic intervention or reoperation to control the bleeding source.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eData Collection\u003c/h2\u003e \u003cp\u003eThe demographics of interest included sex, age, race, ethnicity, and BMI. Pre-operative comorbid conditions included diabetes mellitus, gastroesophageal reflux disease, history of MI, previous percutaneous coronary intervention, previous cardiac surgery, hyperlipidemia, venous stasis, hypertension requiring medication, renal insufficiency, dialysis, current smoker, chronic obstructive pulmonary disease, oxygen dependence, sleep apnea, functional health status, history of PE, history of DVT, inferior vena cava (IVC) filter, therapeutic anticoagulation, chronic steroids, hematocrit value, and number of packed red blood cells. Intraoperative characteristics included operative year, American Society of Anesthesiologists classification (ASA), first assistant training level, surgical approach, operative length, other procedures, drain placed and anastomosis checked. Postoperative variables assessed were swallow study, length of stay (LOS), VTE, anticoagulation initiated, transfusion 72 hours from surgery, acute renal failure, cardiac arrest, stroke, myocardial infarction, progressive renal failure, unplanned Intensive Care Unit admission, drain present at 30 days, death, discharge destination, readmission, reoperation, intervention, emergency department visit, dehydration treatments, and cause of death. Race was reported as White, Black, and Other/unknown. VTE groups were PE, DVT, both (PE and DVT), and none. Discharge destinations were grouped by home (home, facility which was home), skilled (rehab, skilled care, not home, separate acute care), and unskilled (unskilled facility not home, unknown) facility. Age, BMI, preoperative hematocrit level, operative length, number units red blood cells transfused, number of dehydration treatments, number of emergency department visits, days to death were analyzed both as continuous and categorical variables.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003ePrimary and Secondary Outcomes\u003c/h2\u003e \u003cp\u003eThe primary outcome of interest was rate of VTE in patients undergoing primary versus revisional RYGB. The secondary outcome was bleeding requiring blood transfusion. Additional outcomes captured included anticoagulation initiation, readmission, reoperation, intervention, treatment for dehydration, emergency department visit, LOS, length of operation, days to death and most likely cause of death.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eThe cohort with primary RYGB was compared to the group with revisional RYGB surgery. For each analysis, continuous variables were compared using Mann-Whitney U tests and reported as means \u0026plusmn; standard deviation (SD). Categorical variables were compared using Fisher exact tests and reported as counts and percentages.\u003c/p\u003e \u003cp\u003ePropensity score matched analysis was performed to address intergroup bias. Propensity matching was performed with race, ethnicity, BMI\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;50kg/m\u003csup\u003e2\u003c/sup\u003e (binary variable), gastroesophageal reflux disease, diabetes, hypertension, hyperlipidemia, obstructive sleep apnea, smoking, and previous percutaneous coronary intervention based on previous publications on revisional RYGB [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Patients who underwent primary RYGB and those who had revisional RYGB were matched 3:1 based on propensity score. Given the rarity of the event and to further reduce the variance of the treatment effects, a 3:1 instead of a 1:1 matching was selected. Matching was performed with the MatchIt package in R 4.03 (R Core Team, Vienna, Austria) using nearest-neighbor matching with a caliper of 0.25. Standardized difference\u0026thinsp;\u0026lt;\u0026thinsp;0.10 was considered adequate. A covariate-adjusted analysis of VTE was performed with predetermined factors with clinical relevance, which included were age, sex, BMI\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;50kg/m\u003csup\u003e2\u003c/sup\u003e, race, ethnicity, ASA class, hypertension, smoking status, dialysis, venous stasis, history of MI, oxygen dependent status, chronic steroids use, history of DVT, history of PE, IVC filter, mobility status, therapeutic anticoagulation, revisional surgery, presence of paraesophageal hernia, and operation length\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;180 minutes. The transfusion covariate-adjusted model included age, sex, BMI\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;50kg/m\u003csup\u003e2\u003c/sup\u003e, racial group, ethnicity, ASA class, hypertension, smoking status, dialysis, venous stasis, history of MI, chronic steroids use, therapeutic anticoagulation, revisional surgery, presence of paraesophageal hernia, drain placed at time of surgery, and operation length\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;180 minutes.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cem\u003ePrimary vs revisional RYGB - Unmatched groups\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe total number of patients in our study population was 213,330 with 197,186 (92.4%) patients in the primary and 16,144 (7.6%) patients in the revisional RYGB groups (\u003cstrong\u003eSupplemental Table 1\u003c/strong\u003e). Of the primary RYGB group, 19.5% were male and the mean age was 45.1\u0026nbsp;\u0026plusmn;\u0026nbsp;11.8 years. In the revisional RYGB group, 12.0% were male and the mean age was 47.4 \u0026plusmn; 10.9 years. Mean BMI for the primary and revisional RYGB groups were 46.3\u0026nbsp;\u0026plusmn;\u0026nbsp;7.7 kg/m\u003csup\u003e2\u003c/sup\u003e and 44.2\u0026nbsp;\u0026plusmn;\u0026nbsp;7.1 kg/m\u003csup\u003e2\u003c/sup\u003e, respectively.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn the primary RYGB group, 90.9% of cases were laparoscopic and 9.1% were robotic\u003cstrong\u003e.\u003c/strong\u003e In the revisional RYGB group, 87.6% of the cases were laparoscopic and 12.4% were robotic. The operative duration was 121.2\u0026nbsp;\u0026plusmn;\u0026nbsp;54.4 minutes and 153.2\u0026nbsp;\u0026plusmn;\u0026nbsp;74 minutes for the primary and revisional RYGB groups respectively \u003cstrong\u003e(Supplemental Table 2).\u003c/strong\u003e Overall complication rates were low for primary and revisional RYGB groups: MI 0.0% vs 0.1%, cardiac arrest 0.1% vs 0.1%, mortality 0.1% vs 0.2%, and reoperation 2.2% vs 3.7%. Additionally, patients in the primary RYGB group less frequently had LOS \u0026gt; 3 days at 5.1% compared to revisional RYGB at 8.5% (p\u0026lt;0.001). \u0026nbsp;Emergency Department visits, readmissions, reoperations, interventions and drain present at 30 days were higher in the revisional RYGB group. Thirty-day VTE rates were higher for primary RYGB when compared to revisional RYGB group while bleeding rates were elevated in patients in the revisional RYGB group (\u003cstrong\u003eSupplemental Table 3\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePrimary vs revisional RYGB -\u0026nbsp;\u003c/em\u003e\u003cem\u003eMatched groups\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAfter propensity score matching, the sample was reduced to 64,258, with 74.9% (n = 48,116) in the primary RYGB group and 25.1% (n = 16,142) in the revisional group, making for a 2.98:1 ratio of primary to revisional RYGB patients (\u003cstrong\u003eTable 1\u003c/strong\u003e). Covariates were balanced across surgery groups with the exceptions of BMI (primary RYGB had a mean BMI of 45.0\u0026nbsp;\u0026plusmn;\u0026nbsp;7.0 kg/m\u003csup\u003e2\u003c/sup\u003e versus revisional RYGB had a mean BMI of 44.2\u0026nbsp;\u0026plusmn;\u0026nbsp;7.1 kg/m\u003csup\u003e2\u003c/sup\u003e, \u003cstrong\u003eTable 1)\u003c/strong\u003e, chronic obstructive pulmonary disease (1.8% in primary versus 1.4% in revisional, \u003cstrong\u003eTable 1\u003c/strong\u003e), and history of DVT (1.9% in primary versus 2.6% in revisional, \u003cstrong\u003eTable 1\u003c/strong\u003e). Mean standardized difference in covariates used in the propensity model, across surgery types, was 0.033, meaning that adequate balance was achieved.\u003c/p\u003e\n\u003cp\u003ePatients in the revisional RYGB surgery group had a higher proportion of readmission, reoperation and intervention 30 days post-surgery when compared to patients in the primary RYGB group (p\u0026lt;0.001, \u003cstrong\u003eTable 2\u003c/strong\u003e). Also, a higher proportion of emergency department visits (p=0.002) and a LOS \u003cu\u003e\u0026gt;\u003c/u\u003e 3 days (p\u0026lt;0.001) were observed in the revisional RYGB group (\u003cstrong\u003eTable 2\u003c/strong\u003e). Operative times \u003cu\u003eof greater than\u003c/u\u003e 180 minutes were more frequent in the revisional RYGB group compared to the primary RYGB group (28.6% to 13.1%, p\u0026lt;0.001, \u003cstrong\u003eTable 2\u003c/strong\u003e). On subgroup analysis of patients who died within 30 days of operation (n=61), there was no difference when comparing the revisional RYGB cohort to the primary RYGB cohort in days to death (p=0.54, \u003cstrong\u003eTable 2\u003c/strong\u003e) or cause of death (p=0.550, \u003cstrong\u003eTable 2\u003c/strong\u003e). PE was the most common cause of death in both groups (29.4% in the revisional RYGB vs. 18.6% in the primary RYGB group, p=0.550).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePrimary Endpoint\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn an unadjusted logistic regression with VTE as the outcome and surgery type as the sole explanatory variable, the estimated odds ratio (OR) was 1.22 [95% confidence interval (CI) (0.91-1.63)], implying that revisional surgery did not have a statistically significant role in changing the odds of VTE. In an adjusted version of the same regression, the estimated odds ratio was 1.09 [95% CI (0.81-1.47)], again concluding that revisional RYGB surgery did not increase the odds of VTE compared to primary RYGB (\u003cstrong\u003eTable 3\u003c/strong\u003e).In the same analysis,\u0026nbsp;Black patients had increased odds of VTE [OR 1.7, 95% CI (1.27-2.29)] compared to Other and White patients. The odds of VTE were higher in the following groups: group that used chronic steroids relative to the group that did not [OR 1.99 95% CI (1.01-3.91); p=0.046], patients with history of MI [OR 2.83 95% CI (1.4-5.71); p=0.004] and finally, patients with history of DVT [OR 3.01 95% CI (1.66-5.46); p\u0026lt;0.001].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eSecondary Endpoint\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eRevisional RYGB was associated with increased odds of blood transfusion with an adjusted analysis OR of 1.26 [95% CI (1.07-1.49); p=0.005] (\u003cstrong\u003eTable 4\u003c/strong\u003e). Male gender and BMI \u003cu\u003e\u0026gt;\u003c/u\u003e50 kg/m\u003csup\u003e2\u003c/sup\u003e were associated with decreased odds of blood transfusion, while limited mobility, use of therapeutic anticoagulation, hypertension, smoking and having a drain placed at the time of surgery were risk factors for increased odds of transfusion (\u003cstrong\u003eTable 4\u003c/strong\u003e).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe risk of VTE following revisional RYGB surgery is not well described or understood, thus this study used a bariatric specific datafile to further understand the risk in comparison to primary RYGB. The key findings of the present study are three-fold. First, the rate of VTE was low after both primary and revisional RYGB. However, despite the low VTE rates, PE remains the most commonly identified cause of postoperative mortality after bariatric surgery. Second, VTE rates were greater for particular cohorts of patients, thus raising concerns about additional factors including social determinants of health playing a significant role. Lastly, patients undergoing revisional RYGB had higher rates of bleeding and other complications including readmissions, reoperations and other interventions.\u003c/p\u003e \u003cp\u003eIn our study, the 30-day rate of VTE was impressively low for both primary and revisional groups. The rate of PE was 0.1% after primary RYGB and 0.2% after revisional RYGB. This is generally lower than the wide range of previously reported PE rates after bariatric surgery, from 0\u0026ndash;6.4% [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Furthermore, the rate of DVT in our study was 0.1% in both groups and is lower than previously reported DVT rates ranging up to 5.4% following bariatric surgery [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Of note, rates of 30-day VTE at 0.3% for patients undergoing primary or revisional RYGB [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Despite the low rates of VTE following RYGB, it still remains a point of potential post-operative concern because PE is the leading cause of death after bariatric surgery. The focus of VTE treatment is complex and includes weight the goals of treatment with the risk of a complication from bleeding.\u003c/p\u003e \u003cp\u003eAdministering chemoprophylaxis has been the mainstay approach to decrease the rates of VTE. While the data on chemoprophylaxis is extensive and compares type, dose, frequency, and potential therapy extension, it lacks standardization for bariatric surgery patients. Additionally, patients following bariatric surgery are a unique cohort with unique pre-operative and intraoperative characteristics. Interestingly, the VTE rates were lower for patients in this study when compared to patients with gastrointestinal cancer who underwent surgery (2.8%-8.9%) [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] and when compared to those who underwent laparoscopic cholecystectomy for gallbladder disease (0.4%) [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Furthermore, given that the known VTE risk factors such as reoperation, LOS\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;3 days and operations\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;180 minutes in length were all more common in the revisional RYGB, it is surprising that VTE rates were similar after matching. While surprising, it is similar to other literature reports describing revisional RYGB risks [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Overall, it is important to understand the unique characteristics and potential intraoperative challenges faced by patients who have revisional RYGB to properly follow risk for VTE post-operatively.\u003c/p\u003e \u003cp\u003ePE was the most commonly identified cause of death for both groups 30 days from surgery. Thus, it is prudent to maintain a high index of suspicion for VTE in patients undergoing primary and revisional RYGB. Several guidelines have been established to help identify those at increased VTE risk. In 2007, the SAGES guidelines on DVT prophylaxis during laparoscopic surgery were released [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] and were subsequently updated by the American College of Chest Physicians (ACCP) [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Additionally, two post-operative VTE risk calculators currently exist for primary bariatric surgery [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Both risk calculators utilize similar risk factors that included age, male gender, higher BMI, longer operative times [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. In addition to these previously established risk factors for VTE, we identified several other comorbidities that were associated with higher VTE rates following revisional RYGB, including decreased functional ability, use of immunosuppressants, and cardiopulmonary status. Recommendations were made by Aminian et al. to initiate peri-operative chemoprophylaxis for all patients undergoing bariatric surgery, extend post discharge prophylaxis for two weeks in high-risk patients, and extend post-discharge prophylaxis for four weeks in the very high-risk group [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Since the average BMI for revisional RYGB patients is lower in our study, the extended chemoprophylaxis dose and duration of treatment may need to be adjusted further to prevent bleeding events. While several risk factors are accounted for in the Cleveland Clinic risk calculator, an individualized approach that looks at history of VTE, cancer, concurrent estrogen therapy, cerebrovascular accident, and additional critical metrics should be performed at bedside to tailor VTE prophylaxis to the patient [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Therefore, these results could suggest that patients undergoing revisional RYGB have unique challenges where peri-operative and extended chemoprophylaxis may require a different risk-stratification and analysis.\u003c/p\u003e \u003cp\u003eOne of the additional findings in our study was that particular cohorts of patients were at increased risk for VTE. Black race, chronic steroid users, and those with history of MI were all at increased risk for VTE and should be included in the high risk for VTE category. As mentioned earlier, Black patients had higher odds of VTE, and this finding may present an area of potential disparities in healthcare. Black patients undergoing bariatric surgery have been reported to have increased IVC placement and this could be a representation of lower access to care [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. IVC filter placement is no longer standard of care for patients undergoing bariatric surgery preoperatively. Other social determinants of health were not assessed by this study but may very well be related to poor outcomes, increased VTE rates and suboptimal treatment strategies. Race, ethnicity, socioeconomic status should be included in future analyses to determine whether this represents a disparity in clinical care and outcomes.\u003c/p\u003e \u003cp\u003eOur study also looked at the bleeding rates post-operatively. Patients undergoing revisional RYGB were more like to require a transfusion within the first 72 hours after surgery compared to primary RYGB. Higher rates for intraoperative transfusions were previously reported for patients undergoing revisional bariatric surgery (7% vs 0%, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In our study, male gender, BMI\u0026thinsp;\u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;50 kg/m\u003csup\u003e2\u003c/sup\u003e, limited mobility, use of therapeutic anticoagulation, drain placement at the time of surgery, smoking, and hypertension were all associated with increased risk of needing a transfusion.\u003c/p\u003e \u003cp\u003eMore complications and increased healthcare utilization was identified in patients undergoing revisional surgery compared to primary RYGB operation. Consistent with prior studies, readmission, reoperation, intervention, emergency room visits, and LOS\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;3 days were all significantly higher in the revisional RYGB group as well [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Identifying the risk factors for readmission to minimize the risk of such an event is paramount as decreasing readmissions significantly decreased utilization of healthcare resources and was associated with significant cost-savings [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Additionally, revisional RYGB surgery had longer operative times and higher utilization of robotic platform. The increased use of the robot for revisional bariatric surgery echoes the existing literature [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThese finding related to revisional RYGB surgery are important given the ongoing trends in bariatric surgery. The total number of revisional RYGB procedures almost tripled from 2015 to 2019 while primary RYGB procedures remain relatively stable [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. As the frequency of revisional RYGB cases increases, we need to consider whether the use of previously reported VTE risk calculators is applicable to those patients or whether revisional bariatric patients have a unique VTE risk profile requiring new guidelines and different risk calculators. Therefore, identifying VTE risk factors that would warrant extended chemoprophylaxis while attempting to balance the risk of postoperative bleeding should be considered on individual basis and should be elucidated in future prospective studies.\u003c/p\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eThere are several limitations to this study. First, there are limitations that are related to the data available in the MBSAQIP datafile. This dataset does not provide information on several factors including details of perioperative and post-discharge anticoagulation. While an area of focus for weight-based chemoprophylaxis, the type, dose, and length of anticoagulant use were not included in the current data files. Additionally, history of cancer, a known risk factor for VTE, is not included in the MBSAQIP datafile. Furthermore, the MBSAQIP data file does not include a follow up period beyond 30 days and thus dose not capture late VTE or death. Second, there are multiple CPT codes used for revisional surgery, including 43659, an unlisted procedure on the stomach; this may have resulted in omission of some of the revisional cases in our analysis. We used a 3:1 propensity to address treatment (surgery) selection bias and the fact that the primary surgery group and the revisional surgery group in the original sub-population differed widely on a series of baseline covariates. Propensity score matching was chosen as a method of addressing selection bias and balancing baseline covariates between the two groups, Given the rarity of the outcome event (VTE) in our sample, a ratio of 3:1 was chosen, as opposed to a 1:1 match, to increase the sample size and efficiency, although we recognize that there is a possibility that this will introduce added bias to our estimates. We also compared our matching scheme with other schemes using from 1:1 to 1:5 matching ratios and either our original .25 caliper or the optimal caliper of .2 times the standard deviation of the logit of the propensity score. Our scheme has the lowest mean standardized difference (tied with the 1:3 scheme with the optimal caliper) and is only slightly behind the 1:2 scheme with the optimal caliper in terms of median standardized difference. Indicating that the match was effective at balancing the covariates across surgery groups as seen in the demographic and clinical characteristics table post-matching.\u003c/p\u003e \u003cp\u003eLastly, as with any retrospective study, there could be inherent biases including selection bias and bias from inaccurately recorded or missing data. Despite these limitations, the current study provides a comparison of the incidence of VTE between primary and revisional RYGB patients utilizing a large, propensity-matched, sample size.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eRevisional bariatric surgery has been increasing over the past few years. Given that VTE remains a significant source of morbidity and mortality in the bariatric surgery population, it is paramount to look at the relationship between revisional surgery and VTE. While our study demonstrates no increased risk of VTE in revisional RYGB cases when compared to primary RYGB cases, it does show that VTE rates are significantly higher in certain patient cohorts. Some of these cohorts are identified with current VTE prophylaxis risk calculators (such as venous stasis, history of VTE, longer operative times, older age, and higher BMI); however, others are not, including Black race, need for dialysis, history of MI and chronic steroid use. Therefore, it is paramount to have future studies looking at revisional surgeries and identifying other potential variables that may affect VTE rates to have a standardized extended VTE prophylaxis protocol.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding:\u003c/h2\u003e\n\u003cp\u003eThere was no funding for this study.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eKonstantinos Economopoulos and Keri Seymour designed the work; Konstantinos Economopoulos, Nova Szoka, Shaina Eckhouse, Maryna Chumakova-Orin, Keri Seymour helped with the acquisition of data, Maragatha Kuchibhatla, James Merchant, Keri Seymour helped with analysis of data, Konstantinos Economopoulos, Nova Szoka, Shaina Eckhouse, Maryna Chumakova-Orin, Maragatha Kuchibhatla, James Merchant, Keri Seymour helped with interpretation of data and reviewed and approved the manuscript.\u003c/p\u003e\n\u003ch2\u003eData Availability\u003c/h2\u003e\n\u003cp\u003eData is provided within the manuscript and supplementary information files.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAmerican Society for M, Bariatric Surgery Clinical Issues C. ASMBS updated position statement on prophylactic measures to reduce the risk of venous thromboembolism in bariatric surgery patients. Surg Obes Relat Dis. 2013 Jul-Aug;9(4):493\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAminian A, Andalib A, Khorgami Z, Cetin D, Burguera B, Bartholomew J, et al. Who Should Get Extended Thromboprophylaxis After Bariatric Surgery?: A Risk Assessment Tool to Guide Indications for Post-discharge Pharmacoprophylaxis. Ann Surg. 2017;265(1):143\u0026ndash;50.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCampo-Betancourth CF, Ortiz Sebastian S, Estrada Caballero JL, Llopis Torremocha C, Villodre Tudela C, Ruiz de la Cuesta Garcia-Tapia E, et al. Early postoperative complications after gastric bypass revisional surgery in patients with previous sleeve gastrectomy versus primary gastric bypass. Surg Obes Relat Dis. 2022;18(10):1246-52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDaigle CR, Brethauer SA, Tu C, Petrick AT, Morton JM, Schauer PR, et al. Which postoperative complications matter most after bariatric surgery? Prioritizing quality improvement efforts to improve national outcomes. Surg Obes Relat Dis. 2018;14(5):652\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEncinosa WE, Bernard DM, Chen CC, Steiner CA. Healthcare utilization and outcomes after bariatric surgery. Med Care. 2006;44(8):706\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEnglish WJ, DeMaria EJ, Hutter MM, Kothari SN, Mattar SG, Brethauer SA, et al. American Society for Metabolic and Bariatric Surgery 2018 estimate of metabolic and bariatric procedures performed in the United States. Surg Obes Relat Dis. 2020;16(4):457\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFinks JF, English WJ, Carlin AM, Krause KR, Share DA, Banerjee M, et al. Predicting risk for venous thromboembolism with bariatric surgery: results from the Michigan Bariatric Surgery Collaborative. Ann Surg. 2012;255(6):1100\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGould MK, Garcia DA, Wren SM, Karanicolas PJ, Arcelus JI, Heit JA, et al. Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e227S-e77S.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaskins IN, Amdur R, Sarani B, Vaziri K. Congestive heart failure is a risk factor for venous thromboembolism in bariatric surgery. Surg Obes Relat Dis. 2015 Sep-Oct;11(5):1140\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHelm MC, Simon K, Higgins R, Kindel TL, Gould JC. Perioperative complications increase the risk of venous thromboembolism following bariatric surgery. Am J Surg. 2017;214(6):1135\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJamal MH, Corcelles R, Shimizu H, Kroh M, Safdie FM, Rosenthal R, et al. Thromboembolic events in bariatric surgery: a large multi-institutional referral center experience. Surg Endosc. 2015;29(2):376\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMetcalf RL, Al-Hadithi E, Hopley N, Henry T, Hodgson C, McGurk A, et al. Characterisation and risk assessment of venous thromboembolism in gastrointestinal cancers. World J Gastrointest Oncol. 2017;9(9):363\u0026ndash;71.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrystowsky JB, Morasch MD, Eskandari MK, Hungness ES, Nagle AP. Prospective analysis of the incidence of deep venous thrombosis in bariatric surgery patients. Surgery. 2005;138(4):759\u0026ndash;63; discussion 63\u0026thinsp;\u0026ndash;\u0026thinsp;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShen MR, Jiang S, Millis MA, Bonner SN, Bonham AJ, Finks JF, et al. Racial variation in baseline characteristics and wait times among patients undergoing bariatric surgery. Surg Endosc. 2023;37(1):564\u0026ndash;70.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSmith MD, Patterson E, Wahed AS, Belle SH, Berk PD, Courcoulas AP, et al. Thirty-day mortality after bariatric surgery: independently adjudicated causes of death in the longitudinal assessment of bariatric surgery. Obes Surg. 2011;21(11):1687\u0026ndash;92.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSociety of American G, Endoscopic Surgeons Guidelines C. Guidelines for deep venous thrombosis prophylaxis during laparoscopic surgery. Surg Endosc. 2007;21(6):1007\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStein PD, Matta F, Sabra MJ. Pulmonary embolism and deep venous thrombosis following laparoscopic cholecystectomy. Clin Appl Thromb Hemost. 2014;20(3):233\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWinegar DA, Sherif B, Pate V, DeMaria EJ. Venous thromboembolism after bariatric surgery performed by Bariatric Surgery Center of Excellence Participants: analysis of the Bariatric Outcomes Longitudinal Database. Surg Obes Relat Dis. 2011 Mar-Apr;7(2):181\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang L, Tan WH, Chang R, Eagon JC. Perioperative risk and complications of revisional bariatric surgery compared to primary Roux-en-Y gastric bypass. Surg Endosc. 2015;29(6):1316\u0026ndash;20.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1-4 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"obesity-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"obsu","sideBox":"Learn more about [Obesity Surgery](https://link.springer.com/journal/11695)","snPcode":"11695","submissionUrl":"https://submission.springernature.com/new-submission/11695/3","title":"Obesity Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4554753/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4554753/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003ePrimary bariatric surgery is associated with moderate to high risk of venous thromboembolic events (VTE), however the risk for revisional surgery lacks granularity. Our primary objective was to define the risk of VTE following revisional Roux-en-Y gastric bypass (RYGB) compared to primary RYGB.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eAdults who underwent primary or revision/conversion RYGB between January 1, 2015 and December 31, 2019 with a BMI\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;35 kg/m\u003csup\u003e2\u003c/sup\u003e were identified in a bariatric specific database. VTE was defined as pulmonary embolus and/or deep venous thrombosis. 30-day VTE and transfusion rates were compared between the two groups using propensity score matching of 3:1.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003ePrimary RYGB was performed in 197,186 (92.4%) patients compared to 16,144 (7.6%) in the revisional group. Patients in the revisional group had fewer comorbidities than those undergoing primary RYGB. In the matched cohort of 64,258 procedures, there were 48,116 (74.9%) primary RYGB cases compared to 16,142 (25.1%) RYGB revisions. The rate of VTE was similar in the revisional surgery group compared to the propensity matched primary RYGB group (0.4% vs. 0.3%, p\u0026thinsp;\u0026gt;\u0026thinsp;0.580), however transfusion was more common in the revisional group (1.4% vs. 1.0%, p\u0026thinsp;=\u0026thinsp;0.005). Revisional group had higher rates of readmission, reoperation, increased length of stay and operation length\u0026thinsp;\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e\u0026ge;\u003c/span\u003e\u0026thinsp;180 minutes compared to matched primary RYGB group (p\u0026thinsp;\u0026lt;\u0026thinsp;0 .001).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eVTE rates for both primary and revisional RYGB are similar. Revisional RYGB cases impose increased risk of bleeding amongst other outcomes. Thus, identifying those at higher risk of complications is critical.\u003c/p\u003e","manuscriptTitle":"Venous Thromboembolic Events Following Revisional Gastric Bypass: An Analysis of the MBSAQIP Database From 2015 to 2019 Using Propensity Matching","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-15 17:49:05","doi":"10.21203/rs.3.rs-4554753/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-07-20T11:46:34+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-07-13T11:04:05+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-07-07T14:39:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"242219919544748579843213471638344153729","date":"2024-07-05T16:15:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"92006911556343205082927204294505870934","date":"2024-07-04T20:11:27+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-07-02T20:08:48+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-07-02T13:24:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-17T03:49:39+00:00","index":"","fulltext":""},{"type":"submitted","content":"Obesity Surgery","date":"2024-06-09T18:20:01+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"obesity-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"obsu","sideBox":"Learn more about [Obesity Surgery](https://link.springer.com/journal/11695)","snPcode":"11695","submissionUrl":"https://submission.springernature.com/new-submission/11695/3","title":"Obesity Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"44294362-6c39-47f1-8442-94b41ee861ea","owner":[],"postedDate":"July 15th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-07T15:58:47+00:00","versionOfRecord":{"articleIdentity":"rs-4554753","link":"https://doi.org/10.1007/s11695-024-07511-y","journal":{"identity":"obesity-surgery","isVorOnly":false,"title":"Obesity Surgery"},"publishedOn":"2024-10-01 15:56:52","publishedOnDateReadable":"October 1st, 2024"},"versionCreatedAt":"2024-07-15 17:49:05","video":"","vorDoi":"10.1007/s11695-024-07511-y","vorDoiUrl":"https://doi.org/10.1007/s11695-024-07511-y","workflowStages":[]},"version":"v1","identity":"rs-4554753","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4554753","identity":"rs-4554753","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}