VERMONT: Vessel Fractional Flow Reserve (vFFR) Assessment of Stenosis Severity: A Prospective Study.

BACKGROUND: Vessel fractional flow reserve (vFFR) is an angiogram-based technique validated in early studies; however, data on its real-time diagnostic performance and integration into routine workflow remain limited. AIMS: The VERMONT study evaluated the diagnostic accuracy and time efficiency of real-time vFFR versus conventional wire-based FFR in detecting functionally significant coronary lesions. METHODS: We conducted a prospective, single-center, blinded study in which vFFR was measured during coronary angiography and compared with simultaneous wire-based FFR. A wire-based FFR of ≤ 0.80 defined a physiologically significant lesion. RESULTS: In 209 patients with 225 intermediate lesions, only 20 (8.9%) of lesions were excluded from vFFR analysis. vFFR demonstrated an AUC of 0.92 (95% CI, 0.89-0.96) for detecting lesions with FFR ≤ 0.80, achieving 90% sensitivity, 79% specificity, a negative predictive value of 93%, and a positive predictive value of 74%. Interobserver agreement was excellent (r = 0.97, p < 0.001). Real-time vFFR computation was on average 13.9 min faster than wire-based FFR (p < 0.001). CONCLUSION: Real-time vFFR demonstrated excellent diagnostic performance with high sensitivity and NPV for identifying functionally significant intermediate lesions, supporting its use as a reliable screening tool. Importantly, this was achieved with a low exclusion rate, rapid computation time, and minimal interobserver variability, underscoring its practicality in routine clinical practice.