Risk analysis of primary versus reoperative coronary artery bypass grafting

Reoperative coronary artery bypass grafting is being performed with increasing frequency, in part as a function of the increasing pool of patients who have undergone initial coronary artery bypass grafting and in part because of the natural progression of atherosclerosis. The great majority of patients require reoperation because of graft atherosclerosis or because of a combination of graft and native-vessel disease. Significant risk factors for reoperation include the lack of an internal mammary artery graft or incomplete revascularization at the time of the primary operation, age, and New York State Heart Association classification. Despite an increasing experience with reoperations, operative mortality remains high, approximately three to five times that of initial bypass operation. Similarly, reoperations are associated with increased morbidity, including increased rates of bleeding and low output states. Specific problems encountered at reoperation include graft atherosclerosis, progression of native-vessel disease, and a significant increase in perioperative bleeding. Bypass ischemic times tend to be longer. The use of retrograde cardioplegia and blood conservation programs may prove to be effective solutions for these problems. If perioperative results can be improved, it would appear that the long-term outlook for these patients is reasonably good.