Improved Outcome After Coronary Bypass Surgery in Patients With Ischemic Cardiomyopathy and Residual Myocardial Viability

Abstract

Background Although residual myocardial viability in patients with coronary artery disease and extensive regional asynergy is associated with improved ventricular function after coronary bypass surgery, the relationship between viability and clinical outcome after surgery is unclear. We hypothesized that patients with poor ventricular function and predominantly viable myocardium have a better outcome after bypass surgery compared with those with less viability. Methods and Results Seventy patients with multivessel coronary artery disease and left ventricular ejection fractions <40% who underwent preoperative quantitative 201 Tl scintigraphy before coronary bypass surgery were analyzed retrospectively. 201 Tl scintigrams were reviewed blindly, and each segment was assigned a score based on defect magnitude. Segmental viability scores were summed and divided by the number of segments visualized to determine a viability index. The viability index was significantly related to 3-year survival free of cardiac event (cardiac death or heart transplant) after bypass surgery ( P =.011) and was independent of age, ejection fraction, and number of diseased coronary vessels. Patients with greater viability (group 1; viability index >0.67; n=33) were similar to patients with less viability (group 2; viability index ≤0.67; n=37) with respect to age, comorbidities, and extent of coronary artery disease. There were 6 cardiac deaths and no heart transplants in group 1 patients and 15 cardiac deaths and two transplants in group 2 patients. Survival free of cardiac death or transplantation was significantly better in group 1 patients on Kaplan-Meier analysis ( P =.018). Conclusions We conclude that resting 201 Tl scintigraphy may be useful in preoperative risk stratification for identification of patients more likely to benefit from surgical revascularization.