Evaluation of Blood Flow Reserve in Left Anterior Descending Coronary Artery Territory by Quantitative Myocardial Contrast and Doppler Echocardiography Altamiro Filho Ferraz Osório, MD, Jeane Mike Tsutsui, MD, FASE, Ingrid Kowatsch, MD, Vitor Coimbra Guerra, MD, Jose Antônio Franchini Ramires, MD, FACC, Pedro Alves Lemos, MD, Luiz Antc ˆnio Machado Cesar, MD, FACC, and Wilson Mathias Jr, MD, FASE, FACC, São Paulo, Brazil We sought to compare the feasibility and accuracy of myocardial blood flow reserve (MBFR) measured by quantitative real-time myocardial contrast echocar- diography with those of coronary flow velocity reserve (CFVR) obtained by transthoracic Doppler echocardiography for detecting left anterior de- scending coronary artery (LAD) stenosis. We studied 71 patients who underwent adenosine stress con- trast echocardiography, transthoracic Doppler echocardiography, and quantitative coronary an- giography within 1 month. An index of myocardial blood flow (A) was determined by quantification of peak plateau acoustic intensity (A) and micro- bubble replenishment velocity () by contrast echo- cardiography. Feasibilities of qualitative analysis of myocardial perfusion, and CFVR and MBFR mea- surements were 98%, 83%, and 94%, respectively. Patients with LAD stenosis had lower CFVR (1.1  0.4 vs 2.7  0.8, P < .001), MBFR (1.2  0.5 vs 2.5  0.8, P < .001), and  reserve (1.1  0.5 vs 2.4  0.6, P < .001) than those without lesion. Sensitivities, specificities, and accuracies for detecting LAD stenosis were 64%, 93%, and 80% for qualitative analysis of myocardial perfusion; 92%, 94%, and 93% for CFVR; 84%, 87%, and 86% for MBFR; and 80%, 97%, and 89% for  reserve. In this selected study population, CFVR was the best index for detecting LAD stenosis (odds ratio  1.78, 95% confidence interval  1.28- 2.47). (J Am Soc Echocardiogr 2007;20:709-716.) Coronary flow reserve is an important indicator of the physiopathologic significance of coronary artery disease (CAD). 1,2 The widespread use of this concept in clinical practice has been hampered by the lack of a noninvasive, feasible, and reliable method for its mea- surement. Recently, contrast echocardiography has emerged as a new tool for the assessment of myo- cardial perfusion. 3-5 Among the different perfusion imaging techniques currently available, real-time myocardial contrast echocardiography (RTMCE) has the advantage of using low mechanical index, which decreases microbubble destruction and, hence, per- mits the evaluation of myocardial perfusion in real time. 6-8 Its association with high mechanical index flash impulse, to cause complete destruction of microbubbles, provides the basis for the quantifica- tion of myocardial blood flow. Although some stud- ies have correlated myocardial blood flow reserve (MBFR) with other methods for identifying CAD, 9,10 its comparison with coronary flow velocity reserve (CFVR), obtained by transthoracic Doppler echocar- diography (TTDE), 11-14 is not completely defined. Furthermore, the feasibility of both techniques using adenosine as the vasodilator agent in the same group of patients has not been previously tested. The aim of this study was to evaluate the feasibility and diagnostic accuracy of CFVR and MBFR for the detection of left anterior descending coronary artery (LAD) stenosis. METHODS Patients From October 2002 to May 2004 we studied by adenosine stress RTMCE and TTDE 71 patients with suggested CAD, who had coronary angiography ordered by their primary care physicians. The exclusion criteria were: age younger than 18 years, hemodynamic instability, unstable angina, previous myocardial infarction, previous coronary artery bypass surgery, pregnancy, chronic obstructive pulmo- From the Heart Institute (InCor), University of São Paulo Medical School. Supported by Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil. Reprint requests: Wilson Mathias Jr, MD, FASE, FACC, Heart Institute (InCor), University of São Paulo Medical School, Av. Dr. Enéas Carvalho de Aguiar, 44, São Paulo, Brazil, CEP:05403- 000 (E-mail: wmathias@incor.usp.br). 0894-7317/$32.00 Copyright 2007 by the American Society of Echocardiography. doi:10.1016/j.echo.2006.11.016 709