Assessment of myocardial viability in the patients with coronary artery disease by speckle tracking strain rate imaging combined with dobutamine stress echocardiography

Objective To explore the significance and value of two-dimensional speckle-tracking strain rate imaging(SRI) combined with dobutamine stress echocardiography(DSE) for evaluation of viable myocardium in the patients with coronary artery disease(CAD).Methods twenty-seven hospitalized patients with regional wall motion abnormalities(RWMA) and left ventricular systolic dysfunction(left ventricular ejection fraction,LVEF50%) were included in our study.Before coronary angiography and percutaneous coronary intervention(PCI),all of them were examinated by speckle-tracking SRI combined with DSE by Philips iE33 and dual isotope simultaneous acquisition single photon emission computed tomography(DISA-SPECT).Every segment image was acquired and evaluated by wall-motion analysis.By using the Qlab7.0 software,the images of SRI were analyzed quantitatively for the long axis peak-systolic longitudinal strain rate(LSR).PCI was performed within one week after SRI combined with DSE and DISA-SPECT in all patients.The movement of each segment was observed by routine echocardiography 1,3,6 months after PCI,and the presence of improvement was taken as the gold standard of viable myocardium.The area of receiver operating characteristic curves(ROC) was used to assess the sensitivity and specificity of LSR in detection of viable myocardium.Results Of the 165 segments with abnormal wall motion by routine echocardiography,106(64.2%,106/165) showed viable myocardium by gold standard,while 59(35.8%,59/106) showed nonviable myocardium.The sensitivity,specificity and accuracy of DISA-SPECT for assessment of viable myocardium were 87.7%(93/106),81.4%(48/59) and 85.5%(141/165).At rest,the LSR of viable and nonviable myocardium were(-1.12±0.17)s-1 and(-1.05±0.14)s-1(t=16.84,P0.01) respectively.The area of receiver operating characteristic curves(AUC) was 0.694(P0.001)with a cutoff of-1.08.The sensitivity and specificity were 66.7% and 62.7%.When combined with DSE,the LSR of viable and nonviable myocardium were(-1.64±0.31)s-1 and(-1.09±0.42)s-1(t=11.87,P0.01)respectively.The AUC increased significantly up to 0.859(P0.001) with a cutoff of-1.30.The sensitivity and specificity improved to be 84.4% and 85.3%(χ2=9.082,7.394,both P0.05).In detecting viable myocardium in the patients with CAD,the sensitivity of LSR combined with DSE was slightly lower than DISA-SPECT(84.4% vs 87.7%),while the specificity was much higher than DISA-SPECT(85.3% vs 81.4%).But they were no significant difference(χ2=0.621,0.241,both P0.05).There was a good correlation between SRI combined with DSE and DISA-SPECT in detecting viable myocardium(rn=0.819,P0.001).Conclusions The sensitivity and specificity of LSR in quantitative SRI analysis improved significantly when combined with DSE.The sensitivity and specificity of LSR combined with DSE were similar to DISA-SPECT in detecting viable myocardium in the patients with CAD.