A novel intermediate coronary artery stenosis severity method: Fluoroscopy-Assisted Measurement of Coronary Volume Ratio (The FLAME FFR Trial).

Objective: The fluoroscopy-assisted coronary volume measurement (FLASH) algorithm, based on contrast passage time and vessel size, is a simple and non-invasive method of assessing coronary blood volume. The present study evaluated the diagnostic performance of FLASH flow ratio-derived fractional flow reserve (FFRFLAME) compared to wire-based FFR (FFRWB).

Patients And Methods: FFRFLAME was defined as the ratio of FLASH at baseline to maximal hyperemia. Forty-eight patients with one intermediate coronary lesion (30-70% by angiographic visual estimation) were enrolled in this cross-sectional study. FFRFLAME and FFRWB measurements were collected in each patient. Intravenous administration of adenosine was used to achieve maximal hyperemia. The Pearson correlation coefficient and receiver operating characteristic analysis were performed to determine the predictive accuracy of FFRFLAME.

Results: The average age of the patients was 58 years, and 43% (21 of 48) were female. The predominant vessel assessed was the left anterior descending artery system (87.5%). The mean FFRWB was 0.91 ± 0.05 at baseline and 0.83 ± 0.07 at the hyperaemic level, with 27% (13 of 48) of patients having an FFRWB of ≤0.80. For each patient, the mean FFRFLAME was 0.668 ± 0.17. The mean FFRFLAME was 0.85 ± 0.16 for patients having an FFRWB of ≤0.80. A strong relationship existed between FFRFLAME and FFRWB (Pearson's r = - 0.765 p<0.001). The optimal cutoff value of the functional significance of coronary artery stenosis for FFRFLAME was determined to be > 0.84 (AUC: 0.899, 84% sensitivity and 97% specificity) when the FFRWB cutoff value for significant lesions was ≤ 0.80.

Conclusions: FFRFLAME, applied to coronary angiography without the need for an invasive pressure wire, can be a beneficial index for appropriate lesion selection in coronary artery diseases.