Background: The purpose of this study was to evaluate the potential of combined use of transthoracic Doppler echocardiographic coronary flow velocity reserve (CFVR) measurements and findings of retrograde coronary flow in the three main coronary arteries for the assessment of borderline (angiographic diameter stenosis, 50%-75%) and high-grade (angiographic diameter stenosis, 76%-100%) coronary artery stenoses.
Methods: A total of 108 patients scheduled for coronary angiography because of chest pain or acute coronary syndromes were studied. CFVR was measured during adenosine-induced hyperemia in the mid to distal segments of the left anterior descending coronary artery, the marginal branches of the left circumflex coronary artery, and the posterior descending coronary artery, with peak CFVR (pCFVR) <2.0 implying hemodynamic significant stenosis. CFVR results were compared with results from quantitative coronary angiography, with stenosis severity in the left main and three major coronary arteries divided into three groups: (1) diameter stenosis 0% to 49%, (2) diameter stenosis 50% to 75%, and (3) diameter stenosis 76% to 100%.
Results: In patients with antegrade flow in the relevant coronary artery segment, CFVR was successfully measured in the mid to distal left anterior descending artery, the marginal branches of the left circumflex artery, and the posterior descending artery in 97%, 63%, and 75% of patients, respectively. CFVR was significantly different among the stenosis groups, with pCFVR of 2.79 ± 0.77 in group 1, 2.01 ± 0.72 in group 2, and 1.50 ± 0.69 in group 3 (P < .001 among groups). Angiography confirmed retrograde flow in seven of the nine arteries found by transthoracic echocardiography. Findings of pCFVR <2.0 or retrograde coronary artery flow correctly identified 42 of 49 patients with stenoses in group 3, with sensitivity, specificity, and positive and negative predictive values of 86%, 70%, 70%, and 85%, respectively. In group 2, pCFVR values were widely distributed above or below the defined pCFVR cutoff value.
Conclusions: CFVR measurement in the mid to distal left anterior descending artery was feasible in almost all patients, and in the marginal branches of the left circumflex artery and the posterior descending artery in two thirds and three quarters of patients, respectively. Use of the combined echocardiographic criteria had high precision for diagnosing severe coronary stenoses (diameter stenosis, 76%-100%). The functional significance of angiographically borderline stenoses (diameter stenosis, 50%-75%) may be further differentiated by the use of CFVR measurements.
Trial registration: ClinicalTrials.gov NCT00281346.
Copyright © 2011 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.