Transthoracic Doppler Echocardiography for Detection of Stenoses in the Left Coronary Artery by Use of Poststenotic Coronary Flow Profiles: A Comparison with Quantitative Coronary Angiography and Coronary Flow Reserve

Background: The aim of this study was to determine whether poststenotic diastolic-to-systolic velocity ratio (DSVR) assessed by transthoracic Doppler echocardiography could accurately identify significant stenoses in the left coronary artery. Methods: A total of 108 patients scheduled for coronary angiography because of chest pain or acute coronary syndromes were studied. Results: The success rates of peak DSVR (pDSVR) measurements in the distal to mid left anterior descending coronary artery and marginal branches of the left circumflex coronary artery were 85% and 32%, respectively. With peak coronary flow velocity reserve as a reference, pDSVR was significantly higher in arteries with normal coronary flow reserve (peak coronary flow velocity reserve >= 2.0) compared with arteries with reduced coronary flow reserve (peak coronary flow velocity reserve < 2.0) (1.86 +/- 0.32 vs 1.53 +/- 0.31, P < .0001). In comparison with quantitative coronary angiography, pDSVR was significantly higher in lesions with diameter stenosis < 50% compared with those with diameter stenosis of 50% to 75% (1.92 +/- 0.32 vs 1.53 +/- 0.18, P < .0001) or diameter stenosis of 76% to 100% (1.43 +/- 0.13, P < .0001). Receiver operating characteristic curves showed pDSVR < 1.68 to be the optimal cutoff value for identifying both functionally significant stenoses and diameter stenoses >= 50%, with sensitivity of 86% and 90%, specificity of 74% and 84%, positive predictive value of 51% and 71%, and negative predictive value of 94% and 95%, respectively. Conclusions: Transthoracic pDSVR measurements in the distal to mid left anterior descending coronary artery and marginal branches of the left circumflex coronary artery had high accuracy for excluding functionally significant stenoses in the left coronary artery, as well as for identifying angiographic significant stenoses. (J Am Soc Echocardiogr 2013; 26:77-85.)