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 (FFR_FLAME) compared to wire-based FFR (FFR_WB). Patients and Methods: FFR_FLAMEwas 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. FFR_FLAMEand FFR_WBmeasurements 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 FFR_FLAME. 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 FFR_WBwas 0.91 ± 0.05 at baseline and 0.83 ± 0.07 at the hyperaemic level, with 27% (13 of 48) of patients having an FFR_WBof ≤0.80. For each patient, the mean FFR_FLAMEwas 0.668 ± 0.17. The mean FFR_FLAMEwas 0.85 ± 0.16 for patients having an FFR_WBof ≤0.80. A strong relationship existed between FFR_FLAMEand FFR_WB(Pearson's r = - 0.765 p<0.001). The optimal cutoff value of the functional significance of coronary artery stenosis for FFR_FLAMEwas determined to be > 0.84 (AUC: 0.899, 84% sensitivity and 97% specificity) when the FFR_WBcutoff value for significant lesions was ≤ 0.80. Conclusions: FFR_FLAME, 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.