Influence of Body Mass Index on Outcomes of Patients Undergoing Surgery for Acute Aortic Dissection: A Propensity-Matched Analysis

To determine whether body mass index >= 30 kg/m(2) affects morbidity and mortality rates in patients undergoing surgery for type A acute aortic dissection, we conducted a retrospective study of 201 patients with type A dissection. Patients were divided into 2 groups according to body mass index (BMI): nonobese (BMI, <30 kg/m(2); 158 patients) and obese (BMI, >= 30 kg/m(2); 43 patients). Propensity score matching was used to reduce selection bias. The overall mortality rate was 19% (38/201 patients). The perioperative mortality rate was higher in the obese group, both in the overall cohort (33% vs 15%; P=0.01) and in the propensity-matched cohort (32% vs 12%; P=0.039). In the propensity-matched cohort, patients with obesity had higher rates of low cardiac output syndrome (26% vs 6%; P=0.045) and pulmonary complications (32% vs 9%; P=0.033) than those without obesity. The overall 5-year survival rates were 52.5% +/- 7.8% in the obese group and 70.3% +/- 4.4% in the nonobese group (P=0.036). In the propensity-matched cohort, the 5-year survival rates were 54.3% +/- 8.9% in the obese group and 81.6% +/- 6.8% in the nonobese group (P=0.018). Patients with obesity (BMI, >= 30 kg/m(2)) who underwent surgery for type A acute aortic dissection had higher operative mortality rates and an increased risk of low cardiac output syndrome, pulmonary complications, and other postoperative morbidities than did patients without obesity. Additional extensive studies are needed to confirm our findings.