Influence of left ventricular function on survival after coronary artery bypass grafting

Abstract

Preoperative left ventricular function is a most important predictor for survival in patients with ischemic heart disease. To elucidate the optimal timing of recommended coronary artery bypass grafting, we investigated the influence of different aspects of preoperative left ventricular function on relative survival. To calculate the relative survival and estimate the disease-specific survival, we compared 6,514 patients who survived the first month after primary coronary artery bypass grafting with the general Swedish population stratified by age, sex, and 5-year calendar period. In particular we studied the relation between relative survival and different aspects of left ventricular performance, namely left ventricular function at rest, New York Heart Association functional class, and number of previous myocardial infarctions. The three variables (left ventricular function at rest, New York Heart Association functional class, and number of previous myocardial infarctions) as well as age and follow-up year gave independent information concerning relative survival. The results from this multivariate analysis were used to define a risk score for each patient. Patients were categorized into different risk groups. Patients in the low-risk group (30% of the total) showed a survival better than that of the population at large for 9 years after operation. The medium-risk group had no or low excess mortality for about 7 years, and the high-risk group (25%) showed increased excess mortality immediately after operation. If primary coronary artery bypass grafting is performed before the left ventricular function and physical performance deteriorate, survival is excellent.