The impact of body mass index on perioperative outcomes of open and endovascular abdominal aortic aneurysm repair from the National Surgical Quality Improvement Program, 2005-2007

Objectives: Obesity and morbid obesity have been shown to increase wound infections and occasionally mortality after many surgical procedures. Little is known about the relative impact of body mass index (BMI) on these outcomes after open (OAR) and endovascular abdominal aortic aneurysm repair (EVAR). Methods: The 2005-2007 National Surgical Quality Improvement Program (NSQIP), a multi-institutional risk-adjusted database, was retrospectively queried to compare perioperative mortality (in-hospital or 30-day) and postoperative wound infections after OAR and EVAR. Patient demographics, comorbidities, and operative details were analyzed. Obesity was defined as a BMI >30 kg/m(2) and morbid obesity as a BMI >40 kg/m(2). Outcomes were compared with t test, Wilcoxon rank sum, chi(2), and multivariate logistic regression. Results: There were 2097 OARs and 3358 EVARs. Compared with EVAR, OAR patients were younger, more likely to be women (26% vs 17%, P < .001), and less obese (27% vs 32%, P < .001). Mortality was 3.7% after OAR vs 1.2% after EVAR (risk ratio, 3.1; P < .001), and overall morbidity was 28% vs 12%, respectively (relative risk, 2.3; P < .001). Morbidly obese patients had a higher mortality for both OAR (7.3%) and EVAR (2.4%) than obese patients (3.9% OAR; 1.5% EVAR) or nonobese patients (3.7% OAR; 1.1% EVAR). Obese patients had a higher rate of wound infection vs nonobese after OAR (6.3% vs 2.4%, P < .001) and EVAR (3.3% vs 1.5%, P < .001). Morbid obesity predicted death after OAR but not after EVAR, and obesity was an independent predictor of wound infection after OAR and EVAR. Conclusions: Morbid obesity confers a worse outcome for death after abdominal aortic aneurysm repair. Obesity is also a risk factor for infectious complications after OAR and EVAR. Obese patients and, particularly, morbidly obese patients should be treated with EVAR when anatomically feasible. (J Vase Surg 2010;52:1471-7.)