Online Angiography Image-Based FFR Assessment During Coronary Catheterization: A Single-Center Study.

OBJECTIVES: To assess the diagnostic performance of angiography-derived fractional flow reserve (FFRangio) measurements in patients with stable coronary artery disease when used online in the catheterization laboratory during routine coronary angiography. BACKGROUND: FFR, an index of the hemodynamic severity of coronary stenosis, is derived from invasive measurements using a pressure-monitoring guidewire and hyperemic stimulus. While FFR is the gold standard, it remains under-utilized. FFRangio may have several advantages owing to the reduced operator time, no wire-related or procedural complications, and no need for administration of vasodilators. METHODS: FFRangio is a novel technology that uses a patient's hemodynamic data and routine angiograms to generate FFR values at each point along the coronary tree. We present the online application of the system where FFRangio was successfully used in the catheterization laboratory during routine coronary angiography and compared to invasive FFR. Fifty-three patients (79% men) and 60 coronary lesions were analyzed. RESULTS: Values derived using FFRangio ranged from 0.58-0.96 and correlated closely (Pearson's correlation coefficient, r=0.91; P<.001) with the invasive FFR measurements (range, 0.52-0.97). The 95% limits of agreement between invasive and non-invasive FFR ranged from -0.065 to 0.07 using Bland-Altman analysis. For an FFR cut-off value of 0.80, the sensitivity, specificity, and diagnostic accuracy of FFRangio were 86%, 100%, and 95%, respectively. CONCLUSIONS: This is the first report of using the online application of the FFRangio system. In this single-center experience, FFRangio values showed high correlation rates to invasive FFR.

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

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 (FFRangio) may have several advantages. The aim of this study is to assess the diagnostic performance and interobserver reproducibility of FFRangio in patients with stable coronary artery disease. METHODS AND RESULTS: FFRangio is a computational method based on rapid flow analysis for the assessment of FFR. FFRangio 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 FFRangio 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 FFRangio 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 FFRangio 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.