We identified 420 medically treated and 231 surgically treated patients (coronary graft plus myocardial surgery in 30%) who had severe left ventricular dysfunction manifest by an ejection fraction below 0.36 and markedly abnormal wall motion. Compared with medically treated patients, those treated surgically had more severe angina (56.7% vs 29.0% class III or IV; p < .001), less heart failure as predominant symptom (I 1. 1% vs 18.8%; p < .003), more severe coronary disease (66.7% vs 50.2% three-vessel disease; p < .001), a greater concentration of left main coronary artery lesions > 70% (12.6% vs 3.8%: p < .001), and a greater estimated extent of jeopardized myocardium (p < .001). Multivariate regression analysis of survival, which adjusts for the above covariates, showed that surgical treatment prolonged survival (p < .05), although it ranked below severity of heart failure symptoms, age, ejection fraction, and left main stenosis >70% in determining prognosis. Surgical benefit was most apparent for patients with ejection fractions below 0.26 who had a 43% 5 year survival with medical treatment vs 63% with surgery. Surgically treated patients experienced substantial symptomatic benefit compared with medically treated patients if their presenting symptoms were predominantly angina; however, there was no relief of symptoms caused primarily by heart failure. We conclude that patients with predominantly ischemic pain symptoms, despite poor left ventricular function, benefit from surgery; however, operative mortality in this high-risk subset must equal or better the 6.9% obtained in this study. Circulation 68, No. 4, 785-795, 1983. MANY STUDIES have examined the role of coronary surgery in patients with disabling symptoms, advanced coronary vascular lesions, and relatively well-retained myocardial function. However, for patients who have significant left ventricular dysfunction, concerns about increased operative mortality, diminished long-term survival, and irreversibility of myocardial scar have made it difficult to assess the role of coronary surgery in these patients. The NHLBI-sponsored Coronary Artery Surgery Study (CASS) Registry, which enrolled patients from 1974 to 1979, includes many patients with left ventricular dysfunction whose management varied according to local physicians' preferences based on their assessment of patient symptoms and angiographic findings. We retrospectively reviewed those patients who fell below a specific threshold of left ventricular dysfunction and sought to evaluate those variables that determine survival, coronary events, and symptomatic status.

These results contribute to the understanding of the natural history of coronary artery disease and are also of historical interest. The poor survival of patients with three-vessel disease and low ejection fractions continues to emphasize the importance of considering revascularization for these patients.

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This report, which extends follow-up of more than 16 years in CASS Registry patients with LMEQ disease, shows that CABG surgery prolongs life in most clinical and angiographic subgroups. However, median survival was not prolonged by CABG surgery in patients with normal LV systolic function, even if a significant right coronary artery stenosis (> or = 70%) also was present or in patients with an LV ejection fraction > or = 50% who participated in the CASS randomized trial or who were randomizable.