Is there a left main equivalent?

LEFT MAIN coronary artery disease has received considerable attention in the past few years. Studies have indicated that the risk of death due to coronary artery disease correlated best with the extent of coronary artery disease and left ventricular function. The extent of coronary artery disease has been and still is generally categorized as one-, two-, threeand left main coronary artery disease. Earlier studies have found a 1-year mortality after identification at angiography of 25-33% for left main coronary artery disease, 14-19% for three-vessel disease, 7-9% for two-vessel disease, 7-8% for one-vessel disease involving the left anterior descending coronary artery, and 4-5% for one-vessel disease involving the right coronary artery or circumflex marginal arterial system.'-8 Studies of 5-year mortality have also indicated a marked difference in risk, depending on the extent of coronary artery disease. Thus, the annual mortality over a 5-year period for three-vessel disease was around 11%, that for two-vessel disease 7% and that for one-vessel disease 3%.>11 These earlier studies were based on data obtained in the late 1960s and early 1970s. Since then, mortality from coronary artery disease has fallen in the overall population,12 medical treatment has improved, patient selection for coronary angiography has changed, and more detailed attention is given to left ventricular function. Prognosis for any given extent of coronary artery disease is greatly influenced by left ventricular function. For example, McNeer and associates found a 2-year survival in patients with three-vessel disease of 87% if they had normal left ventricular function and 76% if they had poor left ventricular function.'3 Recent experience with medical therapy, while demonstrating the improved survival, still indicates that the extent of coronary artery disease has a major