VERMONT μQFR: Diagnostic Accuracy of Murray Law-Based 2D-μQFR Compared to 3D-μQFR and vFFR

Background: Murray law-based quantitative flow ratio (μQFR) is an angiography-derived physiological index that utilizes a single angiographic projection with artificial intelligence-guided vessel segmentation. Aims: To evaluate the diagnostic accuracy and time efficacy of 2D-μQFR against wire-based fractional flow reserve (FFR ≤ 0.80), compare its performance with 3D-μQFR and vessel-FFR (vFFR), and assess feasibility in lesions excluded from vFFR analysis. Methods: This sub-study of the prospective VERMONT trial analyzed 2D- and 3D-μQFR retrospectively using prospectively acquired angiograms, with wire-based FFR as the reference standard. Results: Among 209 patients with 225 intermediate lesions, 205 lesions were analyzed. 2D-μQFR demonstrated excellent diagnostic accuracy for FFR ≤ 0.80 (AUC 0.95; 95% CI 0.93–0.98), with 93% sensitivity, 92% specificity, 88% positive predictive value (PPV), and 95% negative predictive value (NPV). Inter-observer agreement was excellent (r = 0.94, p < 0.001), and 2D-μQFR analysis was 15.1 min faster than wire-based FFR (1.8 ± 0.7 vs. 16.9 ± 5.4 min, p < 0.001). Diagnostic performance was comparable to that of 3D-μQFR, which achieved an AUC of 0.94 (95% CI 0.91–0.97), with 89% sensitivity, 90% specificity, 86% PPV, and 93% NPV. It was more specific than vFFR, which achieved an AUC of 0.92 (95% CI 0.89–0.96), with 90% sensitivity, 79% specificity, 74% PPV, and 93% NPV. Single-projection analysis was feasible in 85% of lesions excluded from vFFR due to image quality limitations. Conclusion: Single-projection 2D-μQFR provides accurate, rapid, and reproducible physiological assessment comparable to 3D-μQFR with superior specificity to vFFR. These findings support 2D-μQFR as a practical, wire-free alternative to invasive FFR in routine clinical practice.