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Real world validation of the nonhyperemic index of coronary artery stenosis severity—Resting full‐cycle ratio—RE‐VALIDATE
Author(s) -
Kumar Gautam,
Desai Rupak,
Gore Ankita,
Rahim Hussein,
Maehara Akiko,
Matsumura Mitsuaki,
Kirtane Ajay,
Jeremias Allen,
Ali Ziad
Publication year - 2020
Publication title -
catheterization and cardiovascular interventions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.988
H-Index - 116
eISSN - 1522-726X
pISSN - 1522-1946
DOI - 10.1002/ccd.28523
Subject(s) - medicine , fractional flow reserve , cardiology , coronary artery disease , stenosis , receiver operating characteristic , diastole , confidence interval , gold standard (test) , blood pressure , coronary angiography , myocardial infarction
Objective The primary objective was to demonstrate diagnostic equivalence between RFR and iFR in clinical practice. Background The instantaneous wave‐free ratio (iFR), a nonhyperemic pressure ratio (NHPR), has been shown to be noninferior to fractional flow reserve (FFR) in determining coronary artery stenosis severity in intermediate lesions. However, iFR has a number of inherent limitations, including sensitive landmarking of the pressure waveform and the assumption that maximal flow and minimal microcirculatory resistance occur during a fixed period within diastole. The resting full‐cycle ratio (RFR) is a novel NHPR which evaluates the entire cardiac cycle independent of the ECG, landmark identification, and timing within the cardiac cycle. Methods RE‐VALIDATE RFR was designed to determine the diagnostic utility of RFR for the physiological assessment of coronary artery disease in clinical practice compared to iFR. RFR was also tested for equivalence (1% margin), diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), areas under the receiver operated characteristic curve (AUC), and correlations compared to calculated iFR (iFR calc ). Results From two centers, 501 blinded rest‐ and hyperemic pressure recordings from 431 patients were suitable for analysis according to a core laboratory. The mean FFR, RFR, and iFR calc were 0.80 ± 0.09, 0.90 ± 0.08, and 0.90 ± 0.08, respectively. Based on a binary cut‐off approach (RFR/iFR ≤0.89), RFR demonstrated equivalence with iFR calc (95% confidence interval: 0.025–0.019) with overall diagnostic accuracy 97.8%, sensitivity 97.8%, specificity 97.8%, PPV 96.2%, NPV 98.7%, and AUC 0.96 (0.94–0.97, p < .001). RFR had a mean bias 0.003 (95% limits of agreement: 0.019, −0.025). Conclusions RFR was equivalent to iFR in clinical practice. RFR is an alternative NHPR, avoiding the need for hyperemic agents, thus potentially reducing side effects, procedural time and cost compared to FFR.