Comparison of resting distal to aortic coronary pressure with angiography-based quantitative flow ratio.

BACKGROUND Quantitative flow ratio (QFR) is a novel, adenosine-free method for functional coronary lesion interrogation, which is based on 3-dimensional quantitative coronary angiography and computational algorithms. Data on QFR in all-comer patients with intermediate coronary lesions are scarce, and the diagnostic performance in comparison to resting distal to aortic coronary pressure (Pd/Pa) ratio unknown. METHODS A total of 436 patients with 516 vessels undergoing FFR measurements were included in the analysis. Diagnostic performance of QFR, distal to aortic coronary pressure (Pd/Pa) ratio, and anatomic indices versus FFR was assessed. RESULTS FFR ≤0.80 was measured in 19.4% of interrogated vessels. QFR significantly correlated with FFR (r = 0.82, p < 0.001) with good agreement between QFR and FFR (mean difference 0.011, 95% CI 0.008-0.015). The AUC for an FFR ≤0.80 was 0.86 (95% CI 0.83-0.89, p < 0.001) for QFR, 0.76 (0.72-0.80, p < 0.001) for resting Pd/Pa ratio, and 0.63 (0.59-0.67, p < 0.001) for diameter stenosis. The diagnostic accuracy for identifying an FFR ≤0.80 was 93.4% for QFR, 84.3% for resting Pd/Pa ratio, and 80.4% for diameter stenosis. CONCLUSIONS QFR provides a novel diagnostic tool for functional coronary lesion assessment with superior diagnostic accuracy as compared with resting Pd/Pa ratio and anatomic indices. Future studies are needed to determine the non-inferiority of QFR analysis to FFR assessment with respect to clinical outcomes.