TCT-409 Is Minimum Lumen Diameter the Major Determinant of the Diagnostic Performance of Angiography-Based Vessel Fractional Flow Reserve (vFFR) ?

Abstract

Background
The diagnostic performance of Vessel fractional flow reserve (vFFR) for identifying lesions with a fractional flow reserve (FFR) ≤0.80 varied across studies, and the cause remained unclear. (Figure A) We investigated whether quantitative coronary angiography-derived parameters: reference vessel diameter (RVD), minimal lumen diameter (MLD), diameter stenosis (DS) or lesion length (LL) influence the diagnostic performance of vFFR.

Methods
The core lab retrospectively analysed the QCA and vFFR in 406 vessels with concordant FFR and non-hyperemic pressure ratios pooled from a retrospective cohort and a prospective multicenter trial (NCT03857503). Correlations between the absolute vFFR and FFR difference and QCA parameters were assessed. Diagnostic accuracy of vFFR ≤0.80 for detecting FFR ≤0.80 was assessed across quartiles of QCA parameters. ROC curves and their respective areas under the curve (AUC) were compared.

Results
MLD demonstrated the strongest correlation with the absolute difference of vFFR and FFR (r = –0.425, p < 0.001) (Figure B). When stratified by MLD quartiles, the false-positive rate decreased from 36.3% in Q1 (MLD ≤ 1.27 mm) to 3.9% in Q4 (MLD > 1.80 mm); sensitivity declined from 98.3% in Q1 to 53.3% in Q4 (p < 0.001), whereas specificity increased from 15.9% to 95.4% (p < 0.001). The AUC increased from 0.710 (Q1) to 0.848 (Q4), with a non-significant (raw p = 0.07, Bonferroni-adjusted p = 0.43)(Figure C).

Conclusion
The variability in vFFR performance is influenced by vessel geometry. MLD may play a key role, with diagnostic performance becoming more consistent with larger MLD.