Obesity Paradox in Off-Pump Coronary Artery Bypass Surgery: Does It Benefit the Elderly?

Abstract

The obesity paradox is a well-known phenomenon in cardiovascular disease; how it interferes with coronary artery revascularization remains controversial. The purpose of this study was to investigate the impact of obesity body mass index (BMI > 30; in kg/m²) on short- and long-term survival and major adverse cardiovascular event (MACE)-free survival in obese patients after off-pump coronary artery bypass operation. We retrospectively reviewed our prospective cohort of 1,400 consecutive and systematic patients who underwent off-pump coronary artery bypass operation between September 1996 and November 2007 and identified 448 (32%) with preoperative BMI greater than 30. Patients with BMI greater than 30 patients were younger and had a higher prevalence of diabetes, dyslipidemia, hypertension, and percutaneous coronary interventions than patients with BMI less than 30. Thirty-day mortality and perioperative myocardial infarction were similar in both groups. No significant difference was observed for wound infections, sternal dehiscence, and reoperation for bleeding. Overall, long-term survival was comparable in the two groups, although obese patients older than 65 years had a better survival than the nonobese patients even after correction for risk factors (p = 0.04). MACE-free survival at 10 years was 65.3% ± 5.7% in obese and 76.3% ± 2.3% in nonobese patients (p = 0.007). Statistical significance was maintained (p = 0.008) after correction for risk factors. Among MACE, only new episodes of congestive heart failure were more prevalent in obese patients (p = 0.002). In our series of off-pump coronary artery bypass operation, obesity was not an independent cause of short- and long-term mortality and was shown beneficial for older patients. However, obese patients had a lower MACE-free survival because of an increased incidence of rehospitalization for congestive heart failure.