Outcomes after elective abdominal aortic aneurysm repair in obese versus nonobese patients

Objective: Obesity is a worldwide epidemic, particularly in Western society. It predisposes surgical patients to an increased risk of adverse outcomes. The aim of our study was to use a nationally representative vascular database and to compare in-hospital outcomes in obese vs nonobese patients undergoing elective open aortic repair (OAR) and endovascular aneurysm repair (EVAR). Methods: All patients undergoing elective abdominal aortic aneurysm repair were identified in the Vascular Quality Initiative database (2003-2017). Obesity was defined as body mass index ≥30 kg/m². Univariable (Student t-test and χ² test) and multivariable (logistic regression) analyses were implemented to compare in-hospital mortality and any major complications (wound infection, renal failure, and cardiopulmonary failure) in obese vs nonobese patients. Results: We identified a total of 33,082 patients undergoing elective OAR (nonobese, n = 4605 [72.4%]; obese, n = 1754 [27.6%]) and EVAR (nonobese, n = 18,338 [68.6%]; obese, n = 8385 [31.4%]). Obese patients undergoing OAR and EVAR were relatively younger compared with nonobese patients (mean age [standard deviation], 67.55 [8.26] years vs 70.27 [8.30] years and 71.06 [8.22] years vs 74.55 [8.55] years), respectively; (both P < .001). Regardless of approach, obese patients had slightly longer operative time (OAR, 259.02 [109.97] minutes vs 239.37 [99.78] minutes; EVAR, 138.27 [70.64] minutes vs 134.34 [69.98] minutes) and higher blood loss (OAR, 2030 [1823] mL vs 1619 [1642] mL; EVAR, 228 [354] mL vs 207 [312] mL; both P < .001). There was no significant difference in mortality between the two groups undergoing OAR and EVAR (OAR, 2.9% vs 3.2% [P = .50]; EVAR, 0.5% vs 0.6% [P = .76]). On multivariable analysis, obese patients undergoing OAR had 33% higher odds of renal failure (adjusted odds ratio [OR], 1.33; 95% confidence interval [CI], 1.09-1.63; P = .006) and 75% higher odds of wound infections (adjusted OR, 1.75; 95% CI, 1.11-2.76; P = .02) compared with nonobese patients. However, in patients undergoing EVAR, no association was seen between obesity and any major complications. A significant interaction was found between obesity and surgical approach in the event of renal failure, in which obese patients undergoing OAR had significantly higher odds of renal failure compared with those in the EVAR group (OR_interaction, 1.36; 95% CI, 1.05-1.75; P = .02). Conclusions: Using a large nationally representative database, we demonstrated an increased risk of renal failure and wound infections in obese patients undergoing OAR compared with nonobese patients. On the other hand, obesity did not seem to increase the odds of major adverse outcomes in patients undergoing EVAR. Further long-term prospective studies are needed to verify the effects of obesity after abdominal aortic aneurysm repair and the implications of these findings in clinical decision-making.