Plaque characteristics on coronary CT angiography associated with the positive findings of fractional flow reserve and instantaneous wave-free ratio

Abstract

Background:Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are useful in determining indications for revascularization of coronary artery disease (CAD).Although the discordance of FFR and iFR was noted in approximately 20%, this cause has not been well established. We investigated patient background and features on coronary CT angiography (CCTA) showing not only FFR-and iFR-positive findings but also discordance between FFR≤0.8 and iFR≤0.89. Methods：Subjects were consecutive 83 cases with 105 vessels in which stenosis of 30-90% was detected at one vessel of at least 2mm or more in the major epicardial vessels and FFR and iFR was performed within subsequent 90 days, among suspected CAD which underwent CCTA. The factors affecting not only FFR-and iFR-positive findings respectively but also discordance between FFR and iFR were evaluated using logistic regression analysis on per-patient and per-vessel basis. 4 Results:FFR-and iFR-positive findings were observed in 42 vessels (40.0%) and 34 vessels (32.3%) respectively. Discordance between FFR≤0.8 and iFR≤0.89 was observed in 22 vessels (21.0%) of 21 patients. In multivariate logistic analysis, LAD (OR, 3.55; 95%CI, p=0.0217) and lumen volume/myocardial weight (L/M) ratio (OR, 0.93; 0.86-0.99, p=0.0290) were significant predictors for FFR positive findings. For iFR positive findings, LAD (OR, 3.86; 95%CI, 1.12-13.31; p=0.0236) was only significant predictor. In FFR≤0.8 and iFR>0.89 group (15 vessels, 14.3%), positive remodeling (PR) (OR 5.03, p=0.0205) were significant predictors. In FFR>0.8 and iFR≤0.89 group (7 vessels, 6.7%), there were no significant predictors. Conclusions：On CCTA characteristics, a relevant predictor for FFR positive findings included low L/M ratio. PR were significant predictor in FFR-positive, iFR-negative patients among those with discordance between the FFR and iFR.