Role of Transthoracic Doppler Echocardiography in Patients With a Proximal Left Coronary Artery Lesion That Cannot be Diagnosed by Computed Tomography Angiography

The diagnosis of lesions with severe calcium or in-stent stenosis using coronary computed tomography angiography (CCTA) is still difficult. The aim of the present study was to evaluate the accuracy of transthoracic Doppler echocardiography (TTDE) in patients with suspected angina pectoris, who had a proximal left coronary artery (LCA) site that could not be evaluated by CCTA. Fifty-eight patients were evaluated. The proximal LCA was defined as the left main coronary artery and proximal left anterior descending coronary artery. All patients underwent TTDE and had coronary angiography performed as a reference method. We measured the proximal left coronary flow velocity (CFV) by both color and pulse Doppler methods. Proximal coronary flow was detected in 45 (78%) of 58 patients. CFVs measured by both methods were significantly greater in the group with severe stenosis (percent diameter stenosis >70%) than in the groups with moderate stenosis (percent diameter stenosis 40% to 70%) or without stenosis (color Doppler: 148 ± 42 cm/s, 89 ± 40 cm/s, and 41 ± 22 cm/s, respectively, p <0.05; pulse Doppler: 143 ± 61 cm/s, 82 ± 33 cm/s, and 39 ± 17 cm/s, respectively, p <0.05). Receiver operating characteristic curve analysis showed that the optimal CFV cut-off values obtained by color and pulse Doppler to diagnose severe stenosis were 92 cm/s (sensitivity, 100%; specificity, 90%) and 81 cm/s (sensitivity, 100%; specificity, 85%), respectively. In conclusion, TTDE could diagnose proximal LCA stenosis with good accuracy in patients who could not be evaluated by CCTA.