Risk analysis of urgent coronary artery bypass grafting

Abstract

We analyzed the risk factors of morbidity and mortality associated with urgent coronary artery bypass grafting (CABG) for impending myocardial infarcton. Among 1,428 consecutive patients who underwent isolated on-pump CABG between 1992 and 1998, a total of 126 were urgent cases. Their inhospital and long-term data were analyzed by the Kaplan-Meier method or logistic model. The mean number of grafts performed during urgent CABG was 3.2, and arterial reconstruction was performed in 117 (93.9%) cases. Major postoperative complicatons occurred in 64 cases (50.8%), and there were 9 inhospital deaths (7.1%). Significant predictor of inhospital death, identified by multivariate analysis, was a history of cerebral vascular accident. During a mean follow-up period of 3.1 years, there was a total of 7 remote deaths giving an actuarial 5-year survival rate of 93.5% (excluding inhospital deaths). Remote cardiac events occurred in 23 patients, giving an actuarial 5-year event-free rate of 74.8%. Multivariate logistic regression analysis found that risk factors influencing cardiac events were poor left ventricular function, preoperative renal dysfunction, postoperative use of intra-aortic balloon pumping, and postoperative induction of dialysis, while those influencing survival were previous myocardial infarction. Comparing elective CABG performed in the same period, the inhospital mortality of urgent cases was 33.8 times higher. Among hospital-survivors, patients after urgent CABG demonstrated fair long-term survival and future development of cardiac events. All efforts to achieve complete revascularization and frequent use of the internal mammary artery may contribute to improving the long-term results; however, careful management is necessary for patients with poor cardiac function.