IMPACT OF SEVERITY OF CORONARY-ARTERY STENOSIS AND THE COLLATERAL CIRCULATION ON THE FUNCTIONAL OUTCOME OF DYSSYNERGIC MYOCARDIUM AFTER REVASCULARIZATION IN PATIENTS WITH HEALED MYOCARDIAL-INFARCTION AND CHRONIC LEFT-VENTRICULAR DYSFUNCTION

The aim of this study was to assess the influence of the severity of c oronary artery stenosis and the grade of collateral circulation on myo cardial viability in patients with chronic left ventricular (LV) dysfu nction undergoing coronary artery bypass grafting. Forty patients (age 59 +/- 8 years) with old myocardial infarction were studied by dobuta mine stress echocardiography (DSE) before coronary artery bypass graft ing. LV function was assessed using a 16-segment, 5-grade score model. Viability and functional recovery were respectively defined as a redu ction in wall motion score greater than or equal to 1 at low-dose DSE and at follow-up echocardiograms obtained 3 months after surgery. Ther e were 56 stenotic coronary arteries subtending severely dyssynergic m yocardial segments, of which 38 were occluded. Among 186 severely dyss ynergic segments, functional recovery occurred in 42 (23%). There was no significant difference between myocardial regions with patent or oc cluded coronary arteries with respect to prevalence of viability or fu nctional recovery and percentage of viable or recovered segments relat ive to the total number of dyssynergic segments. In patients with tota l occlusion, these parameters were not different between regions with different collateral grades. Sensitivity, specificity, and accuracy of low-dose DSE for prediction of regional functional recovery were 71%, 90%, and 86%, respectively. It is concluded that in patients with chr onic LV dysfunction, the presence of total occlusion of coronary arter ies supplying severely dyssynergic regions does not imply a lower prev alence or extent of functional recovery after revascularization, regar dless of the grade of angiographically visualized collaterals, Low-dos e DSE can identify myocardial regions with a high probability of funct ional improvement after revascularization regardless of the severity o f underlying coronary stenosis or collateralization of the involved co ronary vessel. (C) 1997 by Excerpta Medica, Inc.