Prognostic Value of a Novel Index: Computational Pressure-Flow Dynamics Derived Fractional Flow Reserve in Stable Coronary Artery Disease Patients with Nonischemic Lesions

Introduction: Computational pressure-flow dynamics derived fractional flow reserve (caFFR) is an angiographic-derived index to determine the fractional flow reserve (FFR) in patients with stable coronary artery disease (CAD), without the need of invasive pressure wire and hyperaemic stimulus in FFR. Although the safety of FFR-guided deferral of revascularization in non-ischemic lesions is well-established, clinical events still occur. The aim of the study is to investigate the prognostic implications of caFFR in those without significant ischemia. Methods: 513 stable CAD patients (mean age=64.3±11.1, 57.7% male) with all lesions being nonischemic, defined by caFFR>0.75, without undergoing revascularization were recruited. The study population was divided into high (n=240) and low (n=273) caFFR groups, according to the median value of caFFR (0.89). The primary endpoint was 3-year major adverse cardiac events (MACE), defined as a composite of all-cause mortality, myocardial infarction (MI), target vessel revascularization (TVR) and hospitalization for heart failure. Results: A total of 44 composite events occurred, including 17 all-cause mortality, 2 MI, 8 TVR and 17 hospitalization for heart failure. Following multivariate adjustment, patients in low caFFR group had a significantly higher risk of MACE than those in high caFFR group (adjusted hazard ratio [HR], 3.02; 95% confidence interval [Cl], 1.19-7.71; P=0.02). Every 0.01 decrease in caFFR was associated with a higher risk of MACE (adjusted HR, 1.12; 95%Cl, 1.03-1.21; P<0.01) cardiovascular mortality or TVR (adjusted HR, 1.16; 95%Cl, 1.04-1.32; P=0.02) and hospitalization for heart failure (adjusted HR, 1.18; 95%Cl, 1.04-1.34; P=0.01). Conclusions: In stable CAD patients without significant functional ischemia, caFFR provides valuable prognostic information on adverse cardiac outcomes. This novel index could enhance risk stratification in stable CAD patients with nonischemic lesions.