Prognosis of patients with chronic coronary artery disease and severe left ventricular dysfunction. The importance of myocardial viability.

Background and Aim: The choice of optimal treatment strategy in patients with coronary artery disease (CAD) and severe left ventricular (LV) dysfunction is often difficult. The aim of this study was to compare long-term results of patients with chronic CAD, severe heart failure and a defined scope of myocardial viability treated with coronary revascularization, heart transplantation, or kept on medical therapy.
Methods: From 1993 to 2000, viability evaluation using low-dose dobutamine echocardiography was performed in 124 patients with CAD and LV ejection fraction <or=30%. The dysfunctional myocardial segments were defined as viable if they exhibited improvement in their thickening at any dose of dobutamine or worsening without initial improvement. The patients were divided into five groups and followed up for a mean period of 27+/-23 months. Group A consisted of 39 patients with viability (at least two dysfunctional but viable segments) who were revascularized. Group B consisted of 29 patients with viability treated medically. Groups C (n=23) and D (n=22) comprised patients with non-viable dysfunctional myocardial segments who were revascularized or kept on medical therapy, respectively. Eleven patients referred for heart transplantation after dobutamine echocardiography and 62 patients with ischemic cardiomyopathy transplanted in the same time interval were included in the group of transplanted patients (Group E).
Results: The Kaplan-Meier survival analysis demonstrated a significantly better survival of group A patients as compared with group B patients (P<0.05). The prognostic benefit of revascularization in patients with viability was not manifested until 3 years after the procedure. At 5 years, survival in groups A, B, C, D and E was 89, 60, 67, 50 and 78%, respectively.
Conclusion: In patients with CAD, severe LV dysfunction, and the evidence of viability in dysfunctional myocardium, coronary revascularization improves survival. At least 3-years follow-up is necessary to objectively assess the prognostic effect of coronary revascularization.