Risk Factors for operative mortality and morbidity in patients undergoing coronary artery bypass surgery for stable angina pectoris

Risk factors for a poor early outcome of surgery for stable angina pectoris were evaluated in 2659 consecutive patients from a defined population. The total operative mortality (death within 30 days after surgery) was 2.6% and the frequency of myocardial injury (increase in S-ASAT to greater than 2.0 mu kat l-1 and in S-CKMB to greater than 1.5 mu kat l-1 within 48 h postoperatively or death in the operating room) 14%. Mortality was related to New York Heart Association (NYHA) classification (P less than 0.001), age (less than or greater than 70 years, P = 0.001), duration of symptoms (less than or greater than 8 years, P = 0.001), aortic cross-clamp (ACC) time (P less than 0.001), and cardiopulmonary bypass (CBP) time (P less than 0.001). A multivariate analysis showed that the combination of NYHA class, ACC time and age best predicted operative mortality. Myocardial injury was related to NYHA functional class (P less than 0.001), duration of symptoms (P less than 0.001), regrafting procedure (P less than 0.001), cardiac related dyspnoea (P = 0.015), ACC time (P = 0.001), CPB time (P = 0.001), relative volume of cardioplegic solution (P less than 0.001), and thromboendarterectomy procedure (P = 0.004). The set of variables that best predicted myocardial injury consisted of ACC time, relative volume cardioplegic solution, NYHA class, regrafting procedure and duration of symptoms. However, these risk factors indicated only moderately high risks, and high-risk patients could not be selected with sufficient accuracy.