Does the Instantaneous Wave-Free Ratio Approximate the Fractional Flow Reserve?

作者：Nils P. Johnson, Richard Lloyd Kirkeeide, Kaleab Asrress, William Fuller Fearon, Timothy Lockie, Koen M. Marques, Stylianos A. Pyxaras, Marco Rolandi, Marcel van ’t Veer, Bernard De Bruyne, Jan J. Piek, Nico H.J. Pijls, Simon Robert Redwood, Maria Siebes, Jos A. E. Spaan, Kenneth Lance Gould · 发表于：Journal of the American College of Cardiology · 年份：2013 · DOI：10.1016/j.jacc.2012.09.064 · 被引用次数：98 · 研究领域：Coronary Interventions and Diagnostics、Cardiovascular Health and Disease Prevention、Cardiac Imaging and Diagnostics

OBJECTIVES: This study sought to examine the clinical performance of and theoretical basis for the instantaneous wave-free ratio (iFR) approximation to the fractional flow reserve (FFR). BACKGROUND: Recent work has proposed iFR as a vasodilation-free alternative to FFR for making mechanical revascularization decisions. Its fundamental basis is the assumption that diastolic resting myocardial resistance equals mean hyperemic resistance. METHODS: Pressure-only and combined pressure-flow clinical data from several centers were studied both empirically and by using pressure-flow physiology. A Monte Carlo simulation was performed by repeatedly selecting random parameters as if drawing from a cohort of hypothetical patients, using the reported ranges of these physiologic variables. RESULTS: We aggregated observations of 1,129 patients, including 120 with combined pressure-flow data. Separately, we performed 1,000 Monte Carlo simulations. Clinical data showed that iFR was +0.09 higher than FFR on average, with ±0.17 limits of agreement. Diastolic resting resistance was 2.5 ± 1.0 times higher than mean hyperemic resistance in patients. Without invoking wave mechanics, classic pressure-flow physiology explained clinical observations well, with a coefficient of determination of >0.9. Nearly identical scatter of iFR versus FFR was seen between simulation and patient observations, thereby supporting our model. CONCLUSIONS: iFR provides both a biased estimate of FFR, on average, and an un...