Is body mass index a risk factor for isolated off-pump coronary revascularization?

The influence of body mass index (BMI) as a risk factor for isolated off-pump coronary artery bypass (OPCAB) surgery is unknown. We postulated that BMI ≥ 30 kg/m(2) would adversely affect outcomes following OPCAB at our institution.

From 2002 to 2009, we selected 742 patients (primary, N = 709 [95.6%], re-operative, N = 33 [4.45%]) who underwent isolated OPCAB for analysis. Patients were stratified into groups by BMI: non-obese (BMI < 30 kg/m(2) ) and obese (BMI ≥ 30 kg/m(2)). Preoperative risk, operative characteristics, and postoperative outcomes were analyzed. Risk-adjusted models evaluated the occurrence of any complication and mortality.

Overall crude mortality was 1.5% (11/742). When compared to non-obese (26.12 ± 2.72 kg/m(2)) recipients, the obese (35.81 ± 5.69 kg/m(2)) comprised younger patients (62.46 ± 9.96 years, p < 0.001). Number of diseased vessels, Left ventricular ejection fraction, and baseline renal function was equivalent across groups. Diabetes (53.24%) and hypertension (90.59%) were more prevalent among obese patients (p < 0.001, respectively). Internal mammary artery utilization (p = 0.47), endoscopic vein harvest (p = 0.74), and intra-aortic balloon pump use (p = 0.58) were similar between groups. Interestingly, postoperative blood product requirement was lower in obese versus non-obese recipients (47.35% vs. 56.72%, p < 0.01). Furthermore, intensive care unit stay (p = 0.93), mortality (p = 0.56), and discharge to home (p = 0.09) remained equivalent between groups. Importantly, multivariable logistic regression did not identify BMI ≥ 30 kg/m(2) as an independent predictor of any complication (p = 0.21) or mortality (p = 0.74).

Obesity does not influence operative characteristics or effect outcomes after OPCAB. BMI ≥ 30 kg/m(2) should not be considered a prohibitive risk factor in isolated off-pump coronary revascularization.