Assessment of coronary flow velocity with transthoracic Doppler echocardiography during dobutamine stress echocardiography

OBJECTIVES The purpose of this study was to evaluate the feasibility of measuring coronary flow velocity (CFV) by transthoracic Doppler echocardiography (TTDE) in the left anterior descending coronary artery (LAD) during contrast-enhanced dobutamine stress echocardiography (DSE). We also assessed the value of TTDE for detecting stress-induced myocardial ischemia in the LAD territory. BACKGROUND Noninvasive assessment of both CFV and wall motion during DSE would enhance the diagnostic accuracy of DSE. METHODS One hundred forty-four consecutive patients underwent CFV recording in the distal LAD by TTDE during contrast-enhanced DSE. Regional wall motion score index (WMSI) in the LAD territory and CFV ratio at peak stress (CFV ratio peak), defined as a ratio of CFV at peak stress to basal CFV, were obtained. RESULTS Coronary flow velocity was successfully recorded in 129 patients (90%) at baseline and during dobutamine infusion. Mean value of CFV ratio peak was 2.39 ± 0.83 (range: 0.84 to 4.40). There was good correlation between WMSI at peak stress and CFV ratio peak (r = 0.62, p < 0.001). Coronary flow velocity ratio peak was significantly lower in patients who developed stress-induced wall motion abnormality (WMA) in the LAD territory than it was in those patients without WMA (1.51 ± 0.51 vs. 2.76 ± 0.65, p < 0.001). A CFV ratio peak <2.1 had a sensitivity of 92% and a specificity of 86% for detecting the presence of stress-induced WMA. CONCLUSIONS Assessment of CFV in the distal LAD during DSE is feasible in the majority of cases and provides a CFV ratio for detecting stress-induced myocardial ischemia in the LAD territory.