Survival benefit after revascularization is independent of left ventricular ejection fraction improvement in patients with previous myocardial infarction and viable myocardium

This study was designed to assess the relationships among myocardial viability, changes in left ventricular (LV) ejection fraction after coronary revascularization and long-term event-free survival in patients with previous myocardial infarction and LV dysfunction. We studied 253 patients with previous myocardial infarction and evidence of dysfunctional viable myocardium as assessed by echocardiography and 99mTc-sestamibi imaging. Coronary revascularization was performed in 142 patients, while 111 were medically treated. In revascularized patients, echocardiography was repeated 12 months later to detect LV ejection fraction improvement, defined as an increase of > or =5% compared with baseline. All patients were followed for a mean period of 52+/-29 months. Cardiac death and non-fatal myocardial infarction were considered as events. Event-free survival was higher in revascularized than in medically treated patients (P<0.001). Ejection fraction increased by > or =5% in 82 (58%) revascularized patients, and the extent of viable myocardium was the strongest predictor of such improvement (P<0.001). Event-free survival was similar for patients with (n=82) and patients without (n=60) LV ejection fraction provement after revascularization, and it was better in evascularized than in medically treated patients in the presence of either substantial (> or =5 viable segments) or low-intermediate (1-4 viable segments) viability (both P<0.01). In conclusion, in patients with previous myocardial infarction and evidence of viable myocardium, coronary revascularization procedures improve outcome at long-term follow-up independently of LV ejection fraction improvement.