Does off-pump coronary surgery reduce morbidity and mortality?

Objective: To compare hospital outcomes of on-pump and off-pump coronary artery bypass surgery. Methods: From 1997 to 2000, primary coronary artery bypass grafting was performed in 481 patients off pump and in 3231 patients on pump. Hospital outcomes were compared between propensity-matched pairs of 406 on-pump and 406 off-pump patients. The 2 groups were similar in age (P = .9), left ventricular function (P = .7), extent of coronary artery disease (P = .5), carotid artery disease (P = .4), and chronic obstructive pulmonary disease (P = .5). However, off-pump patients had more previous strokes (P = .05) and peripheral vascular disease (P = .02); on-pump patients had a higher preoperative New York Heart Association class (P = .01). Results: In the matched pairs the mean number of bypass grafts was 2.8 ± 1.0 in off-pump patients and 3.5 ± 1.1 in on-pump patients (P < .001). Fewer grafts were performed to the circumflex (P < .001) and right coronary (P = .006) artery systems in the off-pump patients. Postoperative mortality, stroke, myocardial infarction, and reoperation for bleeding were similar in the 2 groups. There was more encephalopathy (P = .02), sternal wound infection (P = .04), red blood cell use (P = .002), and renal failure requiring dialysis (P = .03) in the on-pump patients. Conclusions: Both off- and on-pump procedures produced excellent early clinical results with low mortality. An advantage of an off-pump operation was less postoperative morbidity; however, less complete revascularization introduced uncertainty about late results. A disadvantage of on-pump bypass was higher morbidity that seemed attributable to cardiopulmonary bypass.