Enhanced Late Survival Following Coronary Artery Bypass Graft Operation for Unstable versus Chronic Angina

Abstract

Late survival following coronary artery bypass operation is time-frame dependent, with a major improvement occurring by 1974. In the cohort of patients undergoing operation between 1974 and mid-1982, subsets were present with further enhanced survival. In this study of 3,575 patients, the urgency of clinical presentation is examined as a survival determinant, and the results are seemingly paradoxical. Among the 1,404 patients with chronic angina, survival at 1 month was 98.3%; at 5 years, 88%; and at 8 years, 79%. Among the 1,008 patients with progressive angina, survival at 1 month was 97.8%; at 5 years, 90%; and at 8 years, 80%. Among the 1,163 patients with unstable angina, 1-month survival was 98.3%; 5-year survival, 92%; and 8-year survival, 89%. The best long-term results were obtained in patients with an acute clinical presentation. Ventricular function was an important determinant of late survival for the groups with chronic ( p < 0.001) and progressive ( p < 0.001) angina, but it had no effect in the group with unstable angina ( p = 0.803). For the patients with chronic angina and good left ventricular (LV) function, survival was 99.5% at 1 month; 92% at 5 years; and 86% at 8 years. For those with poor LV function, the respective survival was 96%, 84%, and 71%. For the patients with progressive angina and good LV function, 1-month survival was 98.9%; 5-year survival, 94%; and 8-year survival, 83%. For those with poor LV function, the respective figures were 96.3%, 85%, and 76%. For the patients with unstable angina and good LV function, survival at 1 month was 97.8%; at 5 years, 92%; and at 8 years, 89%. For those with poor LV function, the respective survival was 98.2%, 91%, and 88%. Late survival is not impaired by poor ventricular function in patients with unstable angina. This unexpected finding suggests greater reversibility in that subset.