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.

Efficacy of contrast medium induced Pd/Pa ratio in predicting functional significance of intermediate coronary artery stenosis assessed by fractional flow reserve: insights from the RINASCI study.

AIMS: The need of adenosine administration for the achievement of maximal hyperaemia limits the widespread application of fractional flow reserve (FFR) in the real world. We hypothesised that Pd/Pa ratio registered during submaximal reactive hyperaemia induced by conventional non-ionic radiographic contrast medium (contrast medium induced Pd/Pa ratio: CMR) can be sufficient for the assessment of physiological severity of stenosis in the vast majority of cases. The aim of the present study was to test the accuracy of CMR in comparison to FFR. METHODS AND RESULTS: Eighty patients with 104 intermediate coronary stenoses were prospectively and consecutively enrolled. CMR was obtained after intracoronary injection of 6 ml of radiographic contrast medium, while FFR was measured after administration of adenosine. Despite the fact that CMR values were significantly higher than FFR values (0.88 [IR 0.80-0.92] vs. 0.87 [IR 0.83-0.94], p<0.001), a strong correlation between CMR and FFR values was observed (r=0.94, p<0.001) with a close agreement at Bland-Altman analysis (95% CI of disagreement: -0.029 to 0.072). ROC curve analysis showed an excellent accuracy of CMR cut-off of ≤0.83 in predicting FFR value ≤0.80 (AUC 0.97 [95% CI: 0.91-0.99, specificity 96.1, sensitivity 85.7]). Moreover, no FFR value ≤0.80 corresponded to a CMR ≥0.88. CONCLUSIONS: CMR is accurate in predicting the functional significance of coronary stenosis. This could allow limiting the use of adenosine to obtain FFR to doubtful cases. In particular, we suggest considering a CMR value ≤0.83 to be significant, a CMR value ≥0.88 as not significant, and inducing maximal hyperaemia using adenosine for FFR assessment when CMR is between 0.84 and 0.87.