PROGNOSTIC VALUE OF THE AMOUNT OF DYSFUNCTIONAL BUT VIABLE MYOCARDIUMIN REVASCULARIZED PATIENTS WITH CORONARY-ARTERY DISEASE AND LEFT-VENTRICULAR DYSFUNCTION

Objectives. The purpose of our study was to assess the prognostic impo rtance of the amount of dysfunctional but viable myocardium in revascu larized patients with coronary artery disease (CAD) and left ventricul ar (LV) dysfunction. Background. The amount of dysfunctional but viabl e myocardium predicts the functional improvement after revascularizati on and may offer more precise risk stratification of patients referred for bypass surgery or coronary angioplasty. Methods. Two hundred and seventy-four consecutive patients,vith CAD and LV ejection fraction le ss than or equal to 40% underwent low-dose dobutamine echocardiography for viability assessment. One hundred and thirty-three of them were r evascularized using either coronary artery bypass surgery (118 patient s) or coronary angioplasty (15 patients) and entered this study. To qu antify the amount of dysfunctional but viable myocardium, wall motion was scored using 16-segment model. The dysfunctional segments were def ined as viable if they exhibited improvement in their thickening by at least 1 grade with dobutamine infusion. The patients were followed up for a mean period of 20 +/- 12 months (range, 2 to 48) for cardiac mo rtality and nonfatal cardiac events including myocardial infarction, u nstable angina pectoris requiring hospitalization and hospitalization for heart failure. Standard follow-up echocardiography was performed 3 to 6 months after revascularization. Results. Twenty-nine patients ex hibited a large amount of dysfunctional but viable myocardium (greater than or equal to 6 segments, group A), 60 patients had a small amount of dysfunctional but viable myocardium (2 to 5 segments, group B) and 44 patients were found to have dysfunctional myocardium irreversibly damaged (group C). Similar prerevascularization LV ejection fractions of 35% +/- 5%, 34 +/- 4%, 36% +/- 4% in groups A, B and C increased to 47% +/- 6% (p < 0.01 vs. baseline, p < 0.01 vs. groups B and C), to 4 0% +/- 5% (p < 0.01 vs. baseline) and to 37% +/- 6% (p = NS vs baselin e), respectively, after revascularization. The greatest functional imp rovement after revascularization in group A patients was accompanied b y a lower rate of cardiac events during follow-up (2 vs. 18 in group B , p < 0.05, and vs. 17 in group C, p < 0.01) and better cardiac event- free survival according to Kaplan-Meier survival analysis (p < 0.05 vs . groups B and C, respectively). Conclusion. In revascularized patient s with CAD and moderate or severe LV dysfunction, the presence of a la rge amount of dysfunctional but viable myocardium identifies patients with the best prognosis. (C) 1998 by the American College of Cardiolog y.