On- and off-pump coronary surgery and perioperative myocardial infarction : an issue between incomplete and extensive revascularization

OBJECTIVE: Complete myocardial revascularization is the standard for coronary artery bypass grafting. It has been shown, however, that off-pump coronary bypass surgery (OPCAB) may reduce completeness of revascularization without affecting perioperative myocardial infarction rates. We evaluated the influence of OPCAB on major postoperative events in a large consecutive cohort of patients, with special emphasis on risk factors for perioperative myocardial infarction. METHODS: From 1995 to 2004, 5935 patients underwent isolated coronary bypass surgery; of these, 4623 (77.9%) and 1312 (22.1%) underwent on-pump coronary surgery (CABG) and OPCAB, respectively. Patients undergoing OPCAB were matched to patients undergoing CABG by propensity score; logistic regression analysis models were used to study predictors of perioperative myocardial infarction. RESULTS: In matched pairs, postoperative mortality, myocardial infarction, stroke, and atrial fibrillation were similar between groups, while reoperation for bleeding, time on ventilator and red blood cell use were lower in patients undergoing OPCAB. The number of distal anastomoses was lower in patients undergoing OPCAB (2.2+/-0.80 in OPCAB vs 2.9+/-0.86 in CABG, p<0.001), as well as complete revascularization rates (61.9% in OPCAB vs 90.0% in CABG, p<0.001). Multivariate analyses, performed on preoperative and intraoperative variables, showed that both incomplete revascularization and increasing numbers of distal anastomoses (even when controlling for completeness of revascularization) were significant predictors of perioperative myocardial infarction, while CABG/OPCAB strategy did not influence it. CONCLUSIONS: The choice of surgical technique did not influence the occurrence of major perioperative complications and of myocardial infarction, which is negatively affected by incomplete or too extensive revascularization strategies