Agreement between coronary flow velocity reserve and stress echocardiography in intermediate-severity coronary stenoses

Visual and quantitative assessments of percent diameter stenosis on coronar y angiography correlate poorly with functional testing, particularly in int ermediate-severity (40%-70%) lesions, yet are frequently relied on to make decisions regarding revascularization, Coronary flow velocity reserve (CFVR ) and relative CFVR (RCFVR) are promising methods for on-line functional as sessment of lesion severity in the catheterization laboratory. We sought to determine the agreement between maximal, mean, and relative CFVR and stres s echocardiography in intermediate-severity stenoses. The results of exerci se or dobutamine stress echocardiography and CFVR measured by intracoronary Doppler were compared in 28 patients referred for assessment of intermedia te-severity stenoses, using 15 patients with either angiographically normal coronary arteries or diameter stenoses > 70% as reference groups. CFVR was measured at least three times in response to a bolus of adenosine in the t arget vessel distal to the stenosis. RCFVR (target/normal vessel CFVR) was also measured in 27 patients, Maximal, mean (of three measures), and relati ve CFVR were calculated. CFVR greater than or equal to 2.0 and RCFVR greate r than or equal to 0.75 were accepted as normal. A minority (29%) of patien ts in the intermediate-severity stenosis group had a positive test by eithe r method. There was good to very good agreement between stress echocardiogr aphy and maximal CFVR (84%, kappa = 0.62, P < 0.0001) and RCFVR (81%, <kapp a> = 0.59, P < 0.001) across the entire patient cohort, though in the inter mediate subgroup concordance was only fair. Using the mean (of three measur es of) CFVR for the same comparison improved the agreement in the intermedi ate subgroup to good (86%, <kappa> = 0.58, P = 0.002), and in the entire co hort the agreement was very good (88%, kappa = 0.74, P < 0.0001). There was only fair correlation between measures of CFVR and percent coronary stenos is. CFVR improved from 1.8 +/- 0.8 to 2.7 +/- 0.7 after percutaneous interv ention (n = 12, P < 0.0001). These results suggest that there is good agree ment between CFVR and stress echocardiography across a wide range of corona ry lesion severity. The mean of three CFVR measurements distal to the targe t vessel stenosis increases diagnostic accuracy. Intracoronary Doppler flow velocity measurements at the time of cardiac catheterization may facilitat e improved decision-making by providing the ability to assess the functiona l significance of coronary stenoses on-line. Cathet Cardiovasc Intervent 20 01;53:29-38. (C) 2001 Wiley-Liss, Inc.