Noninvasive diagnosis of ischemic and nonischemic cardiomyopathy using coronary flow velocity measurements of the left anterior descending coronary artery by transthoracic Doppler echocardiography

Objectives: The purpose of this study was to assess the feasibility and usefulness of coronary flow velocity measurements of the left anterior descending coronary artery (LAD) by transthoracic Doppler echocardiography (TTDE) to differentiate ischemic cardiomyopathy (ICM) from non-ICM in patients. Background: ICM and non-ICM have similar 2-dimensional echocardiographic features, left ventricular dilatation, and diffuse wall-motion abnormalities. TTDE may be useful to differentiate ICM from non-ICM by detecting significant LAD stenosis based on LAD flow signal analysis. Methods: TTDE was performed in 52 consecutive patients with left ventricular dilatation and diffuse wall-motion abnormalities of unknown origin. Peak and averaged systolic and diastolic flow velocities of the distal LAD flow could be recorded and measured from 44 patients (85%). Peak and mean diastolic/ systolic velocity ratio (DSVR) were calculated. Results: By coronary angiogram, 13 patients were given the diagnosis of ICM and 31 of non-ICM. Left ventricular end-diastolic and end-systolic volumes and ejection fraction were similar between ICM and non-ICM. On the other hand, peak DSVR (1.47 +/- 0.38 vs 2.34 +/- 0.67, P <.0001) and mean DSVR (1.40 +/- 0.42 vs 2.24 +/- 0.61, P <.0001) were significantly lower in patients with ICM than non-ICM. Either peak DSVR less than 1.8 or mean DSVR less than 1.8 had a sensitivity of 77% and a specificity of 77% for detecting the presence of severe LAD stenosis and, therefore, the diagnosis of ICM. Conclusion: TTDE is a useful noninvasive method to differentiate ICM from non-ICM.