Detection Of Myocardial Viability In Early Stage Of Reperfused Acute Myocardial Infarction: Dobutamine Stress Echocardiography Versus Ultrasonic Integrated Backscatter Analysis

Objective:The goals of this study were to compare the diagnostic accuracy of low-dose dobuiamine echocardiography (LDDSE) and ultrasonic integrated backscaitcr in detecting myocardial viability and to predict functional recovery of dysfunctional but viable myocardium at 3 months in early stage of reperfused acute myocardial infarction.Methods:Thirteen patients with a first AMI successfully treated with primary coronary angioplasty (TIMI II-III)were studied . LDDSE were performed at a mean of 10 days after AMI. To quantify the amount of dysfunctional but viable myocardium,the left ventricle was divided into 16 segments and wall motion was graded semi quantitatively using the follow scoring system:0 normal,1= mild hypokinesia,2 = severe hypokinesia,3 = akinesia and 4 dyskinesia.. The dysfunctional segments were defined as viable if they exhibited improvement in their thickening by at least 1 grade and biphasic response during dobutamine infusion. Integrated backscatter images were obtained on day 1,3,and 10 after admission,the segment at risk was considered viable when presenting a normal CVIB curve with CVIB4.5dB. In the case of an abnormal cyclic variation pattern,the segment was defined as nonviable. Resting echocardiography was performed at day 21 and 3 months to evaluate the effective recovery of regional wall motion.Results :1. LDDSE detected the viable myocardium with a sensitivity,specificity,positive predictive value and negative predictivevalue of 90.7%,69.5%,84.7%,80.0%,respectively. 2. The sensitivity,specificity,positive predictive value and negative predictive value of LDDSE for hypokinetic segments were 94.9%,100.0%,88.1%,100.0%,and for akinetic segments were 50.0%,88.9%,50.0%,88.9%,respectively. 3. With integrated backscatter images,viable myocardium was detected in day Iwith a sensitivity,specificity,positive predictive value and negative predictive value of 63.0%,73.7%,72.3%,58.3%;and 78.9%,78.9%,82.7%,65.2%,respectively in day 3. Wall motion improvement was preceded by CVIB normalization. 4. A good correlation between CVIB in day 3,10 and LDDSE was noted (p<0.01),otherwise CVIB in day 1 not.Conclusions:Both LDDSE and CVIB can accurately predict the recovery of dysfunctional but viable myocardium in patients with a first AMI revasculized by direct PTCA. A good correlation between CVIB in day 3,10 and LDDSE was noted. CVIB in day 3 can identify viable myocardium before wall motion improvement.