The Impact of Body Mass Index on Perioperative and Postoperative Outcomes for Endovascular Abdominal Aneurysm Repair

Background: There is varying evidence regarding the effects of body mass index (BMI) on outcomes of endovascular aneurysm repair (EVAR). This study investigates the effects of BMI on an index of perioperative and postoperative outcomes after EVAR. Methods: Four hundred ninety-two patients who underwent elective EVAR at Mount Sinai Hospital were included in this study. Patients were classified as either normal weight (BMI = 18.5-25), overweight (BMI = 25-30), or obese (BMI>30). Chi-squared tests were used to determine significant differences between weight classes across an index of outcomes. The following outcomes were collected: intraoperative complications (e.g., conversion to open), perioperative complications (e.g., hematoma, bowel ischemia, and so forth), and postoperative outcomes (endoleak, sac enlargement, sac shrinkage, access site infection, prolonged postoperative length of stay, reintervention, stroke, claudication/lower extremity ischemia, deep vein thrombosis, limb occlusion, renal complications, abdominal aortic aneurysm (AAA) rupture, AAA-related mortality, and all-cause mortality). Kaplan-Meier survival analysis and a log-rank test were used to determine meaningful differences in all-cause mortality following EVAR between the respective weight classes. Subsequently, multivariate Cox proportional hazards were performed for selection of outcomes, with weight classes as predictors. Finally, a multivariate logistic regression was performed for postoperative hospital stay. Subgroup multivariate analysis was also performed examining only class I obese patients, rather than all obese patients. Results: Overweight patients were significantly less likely to experience all-cause mortality up to 9 years after EVAR than normal-weight patients in both Kaplan-Meier and multivariable Cox proportional hazards models. Obese patients similarly had a lower risk of mortality in Kaplan-Meier analysis, but this did not persist in the multivariate analysis. Overweight patients were also significantly less likely to require a postoperative hospital stay longer than 1 day when compared with normal-weight patients. Finally, obese patients were less likely to have a sac shrinkage greater than 5 mm after EVAR, but were also less likely to have an endoleak. Conclusions: This study adds to the debate on the effects of BMI on outcomes of EVAR. Obesity was not a risk factor for negative perioperative or postoperative outcomes after EVAR with the exception of decreased sac shrinkage. Obese patients were less likely to have an endoleak, and overweight patients were protected against all-cause mortality and longer postoperative hospital stays.