Usefulness of Coronary Flow Reserve Measured by Echocardiography to Improve the Identification of Significant Left Anterior Descending Coronary Artery Stenosis Assessed by Multidetector Computed Tomography

Abstract

Multidetector computed tomography (MDCT) detects coronary artery disease. However, an overestimation of coronary artery stenosis and artifacts can prevent accurate identification of significant coronary narrowing. The combination of MDCT with coronary flow reserve (CFR), the hyperemic/baseline peak flow velocity ratio, measured by transthoracic Doppler echocardiography might be helpful. We studied 144 consecutive patients with CFR and quantitative coronary angiography, obtained using both MDCT and invasive coronary angiography (reference method). It was hypothesized that the CFR might provide an incremental value to MDCT in detecting significant (>70%) left anterior descending (LAD) coronary artery stenosis. A CFR cutoff of <2 was used to discriminate significant stenosis. CFR was feasible in 141 (98%) of 144 patients, and MDCT was feasible in 131 (91%) of 144 patients (p <0.02). In a univariate model, the prediction of significant LAD stenosis was slightly, but significantly (p <0.0001), better with CFR (sensitivity 90%, specificity 96%, positive predictive value 84%, negative predictive value 97%, and diagnostic accuracy 94%, chi-square 97.5) than with MDCT (sensitivity 80%, specificity 93%, positive predictive value 71%, negative predictive value 95%, diagnostic accuracy 90%, chi-square 63.2). When the findings from transthoracic Doppler echocardiography and MDCT agreed, the diagnostic accuracy increased (96%; chi-square 86.1, p <0.0001). In a multivariate prediction of significant LAD stenosis using a logistic neural network, CFR overshadowed MDCT, and the area under the receiver operating curve was 0.99. Of the 13 patients missed by MDCT, the diagnostic accuracy of transthoracic Doppler echocardiog-raphy to predict significant LAD stenosis was 100%. Thus, CFR could improve the diagnostic accuracy of MDCT to detect significant LAD stenosis. © 2009 Elsevier Inc. All rights reserved. (Am J Cardiol 2009;104:657-664) Noninvasive coronary angiography by multidetector computed tomography (MDCT) has been increasingly used as a diagnostic tool to study the coronary anatomy in patients with suspected coronary artery disease and/or multiple risk factors. 1-6 Agreement in published studies is substantial that negative findings on MDCT virtually exclude coronary atherosclerosis; however, quantitation of coronary artery stenosis is difficult. 1-6 Therefore, a noninvasive mul-timodality imaging approach integrating morphologic and functional information has been suggested. 7 Transthoracic color Doppler echocardiography (TDE) allows the measurement of the coronary flow reserve (CFR) in the left anterior descending (LAD) coronary artery, 8 a useful parameter to detect significant (70%) narrowing in the native coronary artery, 8 as well as in the stented and/or grafted LAD artery. 9-12 The CFR might provide incremental functional information on the collateral circulation when chronic total coronary occlusion is present. 13 We compared the value of LAD CFR versus MDCT to predict significant (70%) LAD stenosis, using invasive ...

The Additive Diagnostic Role of Coronary Flow Reserve in Noninvasive Evaluation of Coronary Stenosis on Left Descending Artery Previously Detected by Multislice Computed Tomography

“…Our findings are consistent with recently reported results of investigation which for a difference of our study compared diagnostic value of MSCT 40‐slice scanner and CFR in prediction of significant lesion on LAD. According to earlier reports noninvasive measurements of CFR with TDE accurately reflect invasive measurements of CFR by Doppler guide wire method .…”

“…CFR, derived with TDE, can provide valuable information about functional significance of coronary stenosis, but with limitations in regard to relation of microcirculatory dysfunction. Microcirculatory coronary dysfunction, despite angiographically normal epicardial coronary arteries, could reduce CFR in case of hypertrophy (due to aortic stenosis, hypertrophic cardiomyopathy, hypertension), diabetes mellitus, smoking …”

Incremental Value of Coronary Flow Velocity Reserve, Measured by Transthoracic Echocardiography, Compared with Computed Tomography Angiography Alone, for Detecting Flow-Limiting Coronary Stenoses

“…31 Our findings highlight the accuracy of CFVR and CT angiographic assessment compared with invasive QCA when their findings are concordant. When the two modalities are both positive, CFVR and CT angiography are highly specific in predicting coronary stenosis compared with invasive coronary angiography.…”

Transthoracic Echocardiography in the Assessment of Coronary Arteries

“…The sensitivity and specificity of Doppler TTE measurement of CFVR for detecting significant angiographic disease were satisfactory, ranging from 77% to 94% and 65% to 100%, respectively, slightly depending on the study population, dose of stress medications and cut-off value of diameter % stenosis. In one study, CFVR with a cut-off value <2.0 was a significantly better predictor (90%sensitivity, 96%specificity) of LAD stenosis than multidetector computed tomography (80%sensitivity, 93%specificity) and improved the diagnostic accuracy of the latter from 90 to 96% (Pizzuto et al, 2009). A cut-off value <2.0 was appropriate even for the diagnosis of significant stenosis of donor LAD giving collaterals to other arteries (Pizzuto et al, 2004;Iwata et al, 2006).…”