Three-dimensional quantitative coronary angiography and quantification of jeopardised myocardium to predict functional significance of intermediate coronary artery stenosis.

AIMS: Despite the fact that fractional flow reserve (FFR) is better than angiography in guiding PCI, in the real world the choice to perform PCI is generally based on angiography. Three-dimensional quantitative coronary angiography (3D-QCA) may increase the accuracy of angiography, especially in intermediate coronary artery stenosis (ICAS). The aim of the study was to assess the best cut-off values of area stenosis % (AS%) and the extent of jeopardised myocardium for predicting FFR and for excluding the need to perform FFR. METHODS AND RESULTS: FFR, AS% and Myocardial Jeopardy Index (MJI) were assessed in 211 ICAS. MJI (=-0.36; p=0.001), AS% (=-0.35; p=0.001) and presence of a chronic total occlusion (CTO) (=-0.15; p=0.01) were independent predictors of FFR. In patients without CTO (174 lesions), the best cut-offs for the detection of FFR ≤0.80 for AS% and MJI were 61% (AUC=0.76; p<0.001) and 30% (AUC=0.71; p<0.001), respectively. More importantly, the cut-offs of AS% safely to exclude (100% sensitivity) an FFR ≤0.80 were 40% (AUC=0.85, p<0.001) for an MJI ≥30% and 50% (AUC=0.70, p<0.04) for an MJI <30%, respectively. CONCLUSIONS: AS%, MJI and the presence of a CTO predicted FFR values. 3D-QCA in addition to MJI allows the safe exclusion of FFR ≤0.80, limiting FFR assessment to doubtful cases with considerable reduction of costs.

Influence of the amount of myocardium subtended by a stenosis on fractional flow reserve.

BACKGROUND: Fractional flow reserve (FFR) specifically relates to the severity of a stenosis to the mass of tissue to be perfused. Accordingly, the larger the territory to be perfused, the greater the flow and the pressure gradient induced by maximal hyperemia. Although this notion may be considered intuitive, its unequivocal demonstration is still lacking. The aim of our study was to evaluate the influence of the amount of myocardium subtended to an intermediate stenosis on FFR, especially in relation to quantitative coronary angiography. METHODS AND RESULTS: The severity of each lesion was assessed by FFR and 2-dimensional quantitative coronary angiography. The amount of jeopardized myocardium was evaluated using 3 validated scores specifically adapted to this aim: the Duke Jeopardy Score (DJS), the Myocardial Jeopardy Index (MJI), and the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) Lesion Score (ALS). The presence of a concomitant collateralized chronic total occlusion was also reported. A total of 213 intermediate coronary stenoses in 184 patients were enrolled. FFR values were correlated to minimal lumen diameter (r=0.34; P<0.0001) and diameter stenosis (r=-0.28; P<0.0001). FFR was inversely correlated with DJS, MJI, and ALS (r=-0.28, P<0.0001; r=-0.40, P<0.0001; and r=-0.34, P<0.0001). Lesions localized on proximal left anterior descending were related to significantly lower FFR values and to a higher rate of a positive FFR compared with those in distal left anterior descending, left circumflex, and right coronary arteries (0.80±0.09 versus 0.84±0.08 versus 0.88±0.09 versus 0.91±0.04; P<0.0001). The presence of a collateralized chronic total occlusion was associated with significantly lower FFR values (0.80±0.07 versus 0.85±0.09; P<0.005). At multivariate analysis MJI, minimal lumen diameter, and presence of a collateralized chronic total occlusion were confirmed as significant predictors of FFR. CONCLUSIONS: A larger amount of perfused myocardium subtended by a stenosis is associated with a higher probability that an angiographically intermediate coronary stenosis is functionally significant.