Venous coronary artery bypass surgery: a more than 20-year follow-up study

Abstract

Atherosclerosis in venous coronary artery bypass grafts begins early and accelerates from the fifth post-operative year. We studied the influence of 18 variables existing at the time of operation, and of 'classical' risk factors present at 1 and 5 years after operation on the long-term outcome of this type of surgery. Four hundred twenty-eight consecutive patients who underwent isolated venous coronary bypass surgery between April 1, 1976 and April 1, 1977 were followed prospectively. Follow-up was 99.3% complete with a mean duration of 22.8 years for the survivors. Multivariate analysis was performed using the Cox regression model. Actuarial survival after 5, 10, 15 and 20 years is 95, 83, 63 and 47%, respectively. The cumulative probability of event-free survival for cardiac death, acute myocardial infarction and re-intervention at 5, 10, 15 and 20 years, respectively, are 98, 90, 74, 60%; 99, 91, 83, 77%; and 97, 86, 67, 57%. Age and left ventricular functions are continuous incremental risk factors for mortality. Left ventricular function and completeness of revascularization, and age and vessel disease are independent predictors of cardiac death and re-intervention, respectively. Hypertension, diabetes mellitus, hypertriglyceridemia, obesity and smoking, present after operation have an independent influence on the occurrence of cardiac events. Risk factors (still) existing 1 and 5 years after operation have a negative influence on the long-term results. This emphasizes the need of treatment of these 'classical' risk factors still present after operation.