Results of elective cardiac surgery in patients with severe obesity (body mass index ≥ 35 kg/m2)

Abstract

The increasing number of obese patients eligible for cardiac surgery requires risks and benefits to be balanced in this population. To study the results of cardiac surgery in severely obese patients (body mass index [BMI]≥35 kg/m2). In this retrospective study of 3564 patients undergoing elective cardiac surgery between 2004 and 2012, the population was divided into two groups: BMI 20-34.9 kg/m2 (n=3282) and BMI≥35 kg/m2 (n=282). Patients with BMI<20 kg/m2 were excluded due to the well-known increased mortality risk. The primary endpoint was 90-day mortality. A multivariable analysis was performed to identify prognostic factors. Among our patients, 58.2% and 27.7% underwent isolated coronary or valvular surgery, respectively; 9.7% had combined valvular and coronary surgery and 4.4% had other procedures. Severely obese patients were younger: 62.5±9.3 years vs 67.8±10.7 years (P=0.0001). Overall 90-day mortality was 4.0%. Severe obesity did not influence postoperative mortality. In the multivariable analysis, the interaction between preoperative renal failure and severe obesity was an important mortality prognostic factor (hazard ratio: 11.17; P=0.03). Mediastinitis rates were similar between groups in non-diabetic patients; in diabetic patients, severe obesity was associated with higher mediastinitis rates (P=0.002). Superficial wound infections were higher in severely obese patients (P=0.003). Elective cardiac surgery in severely obese patients was not associated with increased perioperative morbimortality, but had a higher superficial wound infection risk. Nevertheless, severe obesity itself should not be a contraindication to elective surgery.