Comparison of coronary artery bypass grafting versus medical therapy on long-term outcome in patients with ischemic cardiomyopathy (a 25-year experience from the Duke Cardiovascular Disease Databank)

Abstract

In this observational treatment comparison in a single center over 25 years, we sought to assess long-term outcomes of coronary artery bypass surgery (CABG) or medical therapy in patients with heart failure, coronary artery disease, and left ventricular systolic dysfunction. The benefit of CABG compared with medical therapy alone in these patients is a source of continuing clinical debate. This analysis considered all patients with New York Heart Association class II or greater symptoms, 1 or more epicardial coronary vessels with a ≥75% stenosis, and a left ventricular ejection fraction <40% who underwent an initial cardiac catheterization at Duke University Medical Center from 1969 to 1994. Patients were classified into the medical therapy group (n = 1,052) or CABG group (n = 339) depending on which therapy they received within 30 days of catheterization. Cardiovascular event and mortality follow-up commenced on the day of CABG, or at catheterization plus 8 days (the mean time to CABG) for the medical therapy arm. A Cox proportional-hazards model was employed to adjust for differences in baseline characteristics. In the first 30 days from baseline, there was an interaction between treatment strategy and number of diseased vessels. Unadjusted, event-free, and adjusted survival strongly favored CABG over medical therapy after 30 days to >10 years regardless of the extent of coronary disease (p <0.001). Thus, regardless of the severity of coronary disease, heart failure symptoms, or ventricular dysfunction, CABG provides extended event-free and survival advantage over medical therapy alone in patients with an ischemic cardiomyopathy.