On-pump versus off-pump coronary artery bypass surgery in high-risk patients: Operative results of a prospective randomized trial (on-off study)

Objective To analyze the risk reduction of cardiopulmonary bypass complications between on-pump and off-pump coronary artery bypass grafting in high-risk patients. Methods This multicenter, prospective, randomized, parallel trial enrolled patients for elective or urgent isolated coronary artery bypass grafting with an additive European System for Cardiac Operative Risk Evaluation of 6 or more. The patients in cardiogenic shock were excluded. The composite primary end point included operative mortality, myocardial infarction, stroke, renal failure, reoperation for bleeding and adult respiratory distress syndrome within 30 days after surgery. The total sample size was 693 patients, according to a scheduled interim analysis at 400 patients enrolled (α-spending = 0.029, Pocock method). Results A total of 411 patients were included in the interim analysis. Randomization assigned 203 patients to on-pump and 208 patients to off-pump treatment. Of the 411 patients, 24 crossed over; thus, 195 patients were actually treated on-pump and 216 off-pump. According to the intention to treat analysis, the rate of the composite primary end point was significantly lower (unadjusted P = .009, adjusted P = .010) in the off-pump group (5.8% vs 13.3%). The risk of experiencing the primary end point was significantly greater for the on-pump group (unadjusted odds ratio, 2.51; 95% confidence interval, 1.23–5.10; P = .011; adjusted odds ratio, 3.07; 95% confidence interval, 1.32–7.14; P = .009). Conclusions Off-pump coronary artery bypass grafting reduces early mortality and morbidity in high-risk patients.