Myocardial revascularization for acute myocardial infarction: benefits and drawbacks of avoiding cardiopulmonary bypass

BACKGROUND: Coronary artery bypass grafting (CABG) for acute myocardial infarction (AMI) is associated with increased mortality compared with CABG in non-AMI patients. Operating without cardiopulmonary bypass (CPB) might reduce this mortality. METHODS: Between January 1992 and December 1998, 225 patients underwent CABG within 7 days of AMI, 119 with CPB and 106 without. The two groups were similar regarding age, gender, left ventricular dysfunction, and incidence of cardiogenic shock. Mean number of grafts per patient was 3.1 in the CPB group, and 1.7 in the no-CPB group (p < 0.0001). RESULTS: Operative mortality in the CPB group was 12% compared with 3.8% without CPB (p = 0.027). Independent predictors of operative mortality were preoperative use of intraaortic balloon counterpulsation (IABP), nonuse of internal thoracic artery (ITA) to the left anerior descending artery, and the use of less than three grafts. Mortality of patients operated on with CPB within 48 hours of AMI was significantly higher (16.5% vs 4.3%, respectively; p = 0.044). However, patients operated on after 48 hours had similar mortality (5.8% vs 3.4%, respectively). Follow-up ranged from 6 to 84 months. Five-year survival (Kaplan-Meier) of both groups was similar (81%). Patients operated on with CPB had similar rates of recurrent angina; however, they had lower prevalence of reinterventions (0.8% vs 6.3%; p = 0.03). CONCLUSIONS: Our study suggests that CPB can be used safely for most patients referred for CABG within the first week of AMI. However, for emergency patients operated on within the first 48 hours of symptom onset, we advocate avoiding CPB because it is associated with lower operative mortality.