BACKGROUND: The aim of this study was to evaluate if a reduced coronary flow reserve determined by transthoracic echocardiography alone or combined with contrast agents may represent a predictive index of significant left anterior descending coronary artery (LAD) stenosis. METHODS: Thirty-four patients (mean age 59+/-9 years) undergoing coronary angiography for coronary artery disease were studied. Coronary stenosis was classified (according to visually determined percent narrowing) as severe (> 75%), moderate (40 to 75%) and mild (< 40%). Coronary blood flow velocities were recorded in each patient at baseline and after low-dose dipyridamole administration by use of a 3.5 MHz transducer with a machine equipped with second harmonic capability and nondirectional color Doppler software. Coronary flow reserve was defined as the ratio of hyperemic to basal diastolic peak velocity. RESULTS: Adequate Doppler recordings in the LAD were obtained by transthoracic echocardiography in 26/34 patients (76%); the infusion of Levovist allowed for the visualization of LAD flow in a further 7 patients, with an overall feasibility of 97%. Coronary flow reserve was significantly higher in the group of patients with mild coronary lesions (2.3+/-0.3) than in patients with moderate (1.68+/-0.29, p = 0.0004) or severe (1.49+/-0.39, p = 0.0005) LAD stenosis. CONCLUSIONS: By use of transthoracic echocardiography combined with contrast agents it is possible to visualize blood flow velocities in the LAD and to evaluate coronary flow reserve after dipyridamole infusion with a non-invasive approach. Combined with angiographic findings, this diagnostic approach could be useful in giving additional information to assess the functional significance of a stenotic coronary lesion.
BACKGROUND: The aim of this study was to evaluate if a reduced coronary flow reserve determined by transthoracic echocardiography alone or combined with contrast agents may represent a predictive index of significant left anterior descending coronary artery (LAD) stenosis. METHODS: Thirty-four patients (mean age 59+/-9 years) undergoing coronary angiography for coronary artery disease were studied. Coronary stenosis was classified (according to visually determined percent narrowing) as severe (> 75%), moderate (40 to 75%) and mild (< 40%). Coronary blood flow velocities were recorded in each patient at baseline and after low-dose dipyridamole administration by use of a 3.5 MHz transducer with a machine equipped with second harmonic capability and nondirectional color Doppler software. Coronary flow reserve was defined as the ratio of hyperemic to basal diastolic peak velocity. RESULTS: Adequate Doppler recordings in the LAD were obtained by transthoracic echocardiography in 26/34 patients (76%); the infusion of Levovist allowed for the visualization of LAD flow in a further 7 patients, with an overall feasibility of 97%. Coronary flow reserve was significantly higher in the group of patients with mild coronary lesions (2.3+/-0.3) than in patients with moderate (1.68+/-0.29, p = 0.0004) or severe (1.49+/-0.39, p = 0.0005) LAD stenosis. CONCLUSIONS: By use of transthoracic echocardiography combined with contrast agents it is possible to visualize blood flow velocities in the LAD and to evaluate coronary flow reserve after dipyridamole infusion with a non-invasive approach. Combined with angiographic findings, this diagnostic approach could be useful in giving additional information to assess the functional significance of a stenotic coronary lesion.