Results of coronary artery surgery in patients with poor left ventricular function (CASS)

Abstract

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 less than .001), less heart failure as predominant symptom (11.1% vs 18.8%; p less than .003), more severe coronary disease (66.7% vs 50.2% three-vessel disease; p less than .001), a greater concentration of left main coronary artery lesions greater than 70% (12.6% vs 3.8%: p less than .001), and a greater estimated extent of jeopardized myocardium (p less than .001). Multivariate regression analysis of survival, which adjusts for the above covariates, showed that surgical treatment prolonged survival (p less than .05), although it ranked below severity of heart failure symptoms, age, ejection fraction, and left main stenosis greater than 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.