| Abstract: |
SUMMARYIn This study. 40 patients with documented coronary artery disease were underwent coronary artery bypass grafting. The selected patients were classified into two groups with a receiver operating characteristic curve:Group I included 22 patients (55%) with DT >150 cm andGroup II 18 patients (45%) with DT ?150 cm.? Group I: included 18 males (81.8%) and 4 females (18.8%)with mean age of 52.7±7.8 years ranging between 38-63 years.? Group II: included 17males (94.4%) and 1 female (5.6 %) with mean age of 53.5±6.4 years ranging between43-70 years.As regards the relevant history findings, there was no significant difference between group I (patients with DT>150 ms) and group II (patients with DT ?150 ms) as regards sex, age or risk factors of ischemic heart disease as hypertension, smoking, DM and hypercholesterolemia. Meanwhile, there was significant difference between both groups regarding risk factors of ischemic heart disease as previous history of myocardial infarction and NYHA (PThe previous history of myocardial infarction usually associated with akinetic and dyskinetic segments supplied with occluded artery and less tendency to have myocardial viability on thallium than hypokinetic segmentsCoronary angiographic data showed that there was insignificant difference between group I (with DT>150) and group II(with DT?150)regarding the number of vessels affectedAs regards the Doppler Echocardiography findings there were significant difference occurs between groups I (with DT>150) and group II (with DT?150) regarding the E wave (p=0.002) and A wave (p=0.001). This difference being higher in the E wave and lower in the A wave of the patients group II.There was also significant difference between both groups regarding the peak E/A velocity ratio (P=0.001). This occurred because; while most of our patients group II had reversed E/A ratio.There were a significant difference between group I (with DT>150) and group II (DT?150) regarding DT(P=As regards 2D and M-mode Echocardiography, There was significant difference between both groups as regarding functional recovery (p=150ms) and lower in group II ( with DT ?150ms).According to the present study, when all subjects were evaluated, EF emerged as an important predictive marker of successful revascularization. Its assessment on echocardiogram predicted the outcome results of revascularization.On Sceintigraphic examination, there were highly significant difference between both groups as regarding Number of viable segments(p=0.001) and perfusion defect size(p=0.05) on Thallium study. This difference being higher in the number of viable segments and lower in the perfusion defect size in group I(with DT>150 ms) and vice versa in group II (with DT?150 ms).On follow up echocardiography, patients were divided into 3 groups based on baseline DT and change in EF after revascularization. Patients with few viable dysfunctional segments (number of segments 1 to 3 by SPECT) had a short DT(68±22) at baseline and failed to recover systolic function after surgery.As the number of viable segments increased (5 to 7 segments by SPECT), EF increased after surgery, but DT (136±13) was still ? 150 ms at baseline. With further increase in the indices of viability (9 to 10 viable segments by SPECT) , DT became > 150 ms (baseline value), and after revascularization the majority of these patients exhibited an improvement in EF.As expected, ?EF after surgery also was different between the 3 groups: patients with 1 to 3 viable segments had no increase in EF, Those with 5 to 7 segments had an increment of 6.7±1.9% and the patients with 9 to 10 segments had the largest increase: 9.4±3.2%.This study shows a strong association of the mitral inflow pattern with indices of myocardial viability in patients with IC undergoing CABG. These results help explain the association of DT with survival. As shown, when DT was ? 150 ms, Echocardiography and SPECT indices of viability were reduced. Another important and novel finding of our investigation is the ability of DT to predict functional recovery after revascularization.This study observed a strong inverse correlation between DT and number of viable segments by SPECT. The presence of a short DT was associated with a smaller number of viable segments, a lack of recovery of LV systolic function, and a worse clinical outcome after revascularization. These results were derived from a population undergoing CABG and may not be applicable to patients who are deemed unsuitable for mechanical revascularization.As regards the relation between the functional recovery (?EF) at 3 months and other parameters there was a high significant correlation were observed between the functional recovery and DT. Other significant correlation between the functional recovery and number of viable segments and number of perfusion defect size.CONCLUSIONWith the increasing number of patients presenting with ischemic cardiomyopathy, assessment of myocardial hibernation and prediction of functional recovery after myocardial revascularization have become common clinical issues.The reduced amount of viable myocardium may be the link that explains why the restrictive mitral inflow pattern is a powerful predictor of survival in patients with ischemic cardiomyopathy. More importantly, our study identifies the mitral inflow pattern as a potential predictor of viability and functional recovery in patients with myocardial hibernation. In the presence of ?5 to 7 viable segments, EF may still improve after revascularization despite a short DT.The present study shows that patients with low EF, multivessel CAD and greater extent of viability on preoperative rest-redistribution Thallum-201 have better short- and long- term outcome after CABG than similar patients with lesser amounts of viability.These data suggest that the extent of viability in patients with ischemic cardiomyopathy is an important predictor of long- term prognosis after coronary bypass surgery.
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