Validation Study of Image-Based Fractional Flow Reserve During Coronary Angiography

Abstract

Background: Fractional flow reserve (FFR), an index of the hemodynamic severity of coronary stenoses, is derived from invasive measurements and requires a pressure-monitoring guidewire and hyperemic stimulus. Angiography-derived FFR measurements (FFR_angio) may have several advantages. The aim of this study is to assess the diagnostic performance and interobserver reproducibility of FFR_angio in patients with stable coronary artery disease.

Methods and results: FFR_angio is a computational method based on rapid flow analysis for the assessment of FFR. FFR_angio uses the patient's hemodynamic data and routine angiograms to generate a complete 3-dimensional coronary tree with color-coded FFR values at any epicardial location. Hyperemic flow ratio is derived from an automatic resistance-based lumped model of the entire coronary tree. A total of 203 lesions were analyzed in 184 patients from 4 centers. Values derived using FFR_angio ranged from 0.5 to 0.97 (median 0.85) and correlated closely (Spearman ρ=0.90; P<0.001) with the invasive FFR measurements, which ranged from 0.5 to 1 (median 0.84). In Bland-Altman analyses, the 95% limits of agreement between these methods ranged from -0.096 to 0.112. Using an FFR cutoff value of 0.80, the sensitivity, specificity, and diagnostic accuracy of FFR_angio were 88%, 95%, and 93%, respectively. The intraclass coefficient between 2 blinded operators was 0.962 with a 95% confidence interval from 0.950 to 0.971, P<0.001.

Conclusions: There is a high concordance between FFR_angio and invasive FFR. The color-coded display of FFR values during coronary angiography facilitates the integration of physiology and anatomy for decision making on revascularization in patients with stable coronary artery disease.

Clinical trial registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03005028.

Keywords: angiography; catheterization; microcirculation; tomography; workflow.