Prognostic value of myocardial ischemia and viability in patients with chronic left ventricular ischemic dysfunction

Background-Previous studies showed that thallium scintigraphy and dobutamin e echocardiography were accurate, noninvasive ways of predicting contractil e recovery after revascularization in patients with left ventricular (LV) d ysfunction. However, the prognostic impact of such methods remains uncertai n. Methods and Results-We prospectively studied 137 consecutive patients with coronary disease and LV dysfunction who underwent exercise-redistribution-r einjection thallium scintigraphy and dobutamine echocardiography to identif y myocardial ischemia and viability. A total of 94 patients subsequently un derwent revascularization, and 43 underwent medical treatment. The primary endpoint was cardiac mortality, and mean follow-up was 33+/-10 months. Twen ty-four patients died of cardiac causes. By Cox's regression analysis, long -term survival was related to the extent of coronary disease, the presence of diabetes, type of treatment, the presence of ischemic myocardium as dete rmined by thallium scintigraphy, and the presence of viable myocardium as d etermined by both tests, Three-year survival was greater in patients with i schemic myocardium (as determined by thallium scintigraphy) or viable myoca rdium (as determined by both tests) who underwent revascularization than in the other groups (P=0.018 with thallium; P<0.001 with dobutamine). Subgrou p analyses indicated that among patients with 1- or 2-vessel disease, only those with ischemic or viable myocardium improved survival after revascular ization, whereas in patients with 3-vessel or left main diseases, revascula rization always improved survival, albeit more in the presence of ischemic or viable myocardium. Conclusions-Among the parameters commonly available in patients with LV isc hemic dysfunction, the presence of ischemic myocardium (as determined by th allium scintigraphy) and that of Viable myocardium (as determined by dobuta mine echocardiography) are independent predictors of subsequent mortality. These observations may be useful in the preoperative selection of patients for revascularization.