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

Abstract

The aim of this study was to assess the influence of the severity of coronary artery stenosis and the grade of collateral circulation on myocardial viability in patients with chronic left ventricular (LV) dysfunction undergoing coronary artery bypass grafting. Forty patients (age 59 { 8 years) with old myocardial infarction were studied by dobutamine stress echocardiography (DSE) before coronary artery bypass grafting. LV function was assessed using a 16-segment, 5-grade score model. Viability and functional recovery were respectively defined as a reduction in wall motion score ¢1 at low-dose DSE and at follow-up echocardiograms obtained 3 months after surgery. There were 56 stenotic coronary arteries subtending severely dyssynergic myocardial segments, of which 38 were occluded. Among 186 severely dyssynergic segments, functional recovery occurred in 42 (23%). There was no significant difference between myocardial regions with patent or occluded coronary arteries with respect to prevalence of viability or functional recovery and percentage of viable or recovered segments relative to the total number of dyssynergic segments. In patients with total 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 chronic LV dysfunction, the presence of total occlusion of coronary arteries supplying severely dyssynergic regions does not imply a lower prevalence or extent of functional recovery after revascularization, regardless of the grade of angiographically visualized collaterals. Low-dose DSE can identify myocardial regions with a high probability of functional improvement after revascularization regardless of the severity of underlying coronary stenosis or collateralization of the involved coronary vessel. ᮊ1997 by Excerpta Medica, Inc.( Am J Cardiol 1997;79:883-888) P revious studies have demonstrated the value of coronary artery bypass grafting in amelioration of symptoms, improvement of left ventricular (LV) function and prolongation of survival in patients with chronic ischemic LV dysfunction. 1,2 The assessment of myocardial viability is important to predict the occurrence of functional improvement of dyssynergic myocardium after revascularization. 3,4 The utility of various techniques in this setting has been established. These include positron emission tomography, thallium-201 scintigraphy, and low-dose dobutamine echocardiography. [2][3][4] Few studies have asFrom the Thoraxcenter, University Hospital Rotterdam-Dijkzigt, Erasmus University, Rotterdam, The Netherlands. This study was supported in part by the Department of Cardiology, Cairo University Hospital, Cairo, Egypt and Grant NHS 94.135 from the Dutch Heart Foundation, Den Haag, The Netherlands. Manuscript received July 8, 1996; revised manuscript received and accepted November 8, 1996.Address for reprints: Abdou Elhendy, MD, PhD, Thora...

Prediction of Left Ventricular Functional Recovery by Dobutamine Echocardiography, F-18 Deoxyglucose or ^99mTc Sestamibi Nuclear Imaging in Patients with Chronic Myocardial Infarction

“…Left ventricular recovery occurred in 27% of patients, a proportion similar to previous studies with a comparable set of patients [11, 18, 19]. However, most previous studies are devoid of any angiographic follow-up information about restenosis or reocclusion and the relation to functional recovery [18, 19, 20, 21].…”

“…However, most previous studies are devoid of any angiographic follow-up information about restenosis or reocclusion and the relation to functional recovery [18, 19, 20, 21]. In the current study, left ventricular recovery only occurred in patients with successful revascularization and unrestricted perfusion at follow-up.…”

The effect of collateral circulation on left ventricular systolic function

“…These findings might be considered as indirect evidences demonstrating the beneficial effects of CCC on LV systolic function [17]. There have been studies [5,9,18,19] demonstrating the absence of relationship between LV systolic function and CCC, whereas some studies demonstrated a weak relationship [20], or a close relationship [8,10,21], between these two parameters. The discordance in the results of the previous studies might be due, in part, to the inclusion of a nonuniform patient population, often with multivessel coronary artery disease or various degrees of incomplete coronary occlusion.…”

“…Coronary collateral circulation (CCC) usually supplies basal level of perfusion to the ischemic myocardium and maintains the tissue viability [2,3]. Despite shortcomings of the data concerning the relationship between CCC and myocardial viability, CCC does not generally appear to perfuse the nonviable myocardial tissue [4][5][6]. Conflicting studies exist concerning the functional importance of CCC [3,[7][8][9].…”

Ultrasound imaging versus morphopathology in cardiovascular diseases. Coronary collateral circulation and atherosclerotic plaque

“…However, dobutamine-induced wall motion worsening in myocardial territories supplied by occluded epicardial vessels has been reported in case of evident collateral circulation [38], thus emphasizing the importance of a preserved, though reduced, blood flow to distinguish jeopardized myocardium from necrotic tissue. Differently, the ability of low-dose dobutamine stimulation to identify myocardial regions with a high probability of functional improvement after revascularization seems to be independent of both severity of underlying coronary stenosis and degree of collateralization of the involved coronary vessel [39]. …”