Bifurcation lesions: Functional assessment by fractional flow reserve vs. anatomical assessment using conventional and dedicated bifurcation quantitative coronary angiogram

Abstract

The purpose of this study was to compare the performance of both conventional quantitative coronary angiography (QCA) and the dedicated three branch QCA model for bifurcations in the prediction of a functionally significant lesion according to fractional flow reserve (FFR) in patients with bifurcation lesions. Twenty patients with bifurcation lesions underwent coronary angiography together with a functional evaluation of both the main branch and side-branch using FFR. QCA was performed off-line with both conventional QCA software (CAASII, Pie Medical Imaging, Maastricht, The Netherlands) and three branch QCA software (CAAS5, Pie Medical Imaging, Maastricht, The Netherlands). A stenosis was considered hemodynamically significant when the FFR value was ≤ 0.80 and anatomically significant when the diameter stenosis was >50%. The QCA and FFR data were correlated by means of the Pearson correlation. Eighteen bifurcation lesions were suitable for the QCA analysis. In the main vessel, a significant inverse correlation with FFR was seen with both conventional QCA (Pearson r = 0.52 for the MV, P = 0.02), and the three branch QCA model (Pearson r = 0.67 for the MV, P = 0.002). Conversely, in the side-branch, the correlation between QCA and FFR was only significant with the three branch QCA model (Pearson r = 0.57, P = 0.02 for the SB). In bifurcation lesions the correlation between the anatomic severity of a coronary stenosis and its functional significance appears to be somewhat higher when QCA is performed using the three branch model. This is most notable for side-branch stenoses which can be overestimated when using conventional QCA.