Invasive physiologic assessment of coronary artery stenosis by resting full-cycle ratio and fractional flow reserve: a prospective observational study

Resting full-cycle ratio (RFR), an alternative to fractional flow reserve (FFR) for evaluating intermediate coronary artery stenosis, helps reduce patients’ time, cost, and discomfort. However, the validation data for RFR and FFR are lacking. We aimed to assess the diagnostic accuracy of RFR and FFR and evaluate effective decision-making for revascularization using their values. Patients subjected to an invasive physiological study for intermediate coronary artery stenosis in Yongin Severance hospital between October 2020 and April 2022 were prospectively and consecutively recruited. We evaluated the correlation between RFR and FFR measurements and the diagnostic performance of RFR (≤ 0.89) versus FFR (≤ 0.80). In all, 474 intermediate coronary stenosis lesions from 400 patients were evaluated using RFR and FFR values. There was a strong linear relationship between RFR and FFR (r = 0.75, 95% CI 0.70–0.78, p