Validation of Coronary Angiography-Derived Vessel Fractional Flow in Heart Transplant Patients with Suspected Graft Vasculopathy

Abstract

<h3>Purpose</h3> Cardiac transplant-related arteriopathy remains a leading cause of morbidity and mortality in heart transplant (HTx) recipients. Recently, vessel fractional flow reserve (vFFR) derived from coronary angiography has emerged as a new diagnostic computational tool to functionally evaluate the severity of coronary artery disease (CAD). Although vFFR estimates have been shown to perform well against invasive FFR in atherosclerotic CAD, data on the use of vFFR in HTx recipients are lacking. The aim was to validate coronary angiogram-derived FFR to calculate FFR in HTx patients with and without cardiac transplant-related arteriopathy. <h3>Methods</h3> Prospective, single center study of HTx patients referred for annual check-up, undergoing surveillance coronarography. Invasive FFR was measured using a motorized device at the speed of 1.0 mm/sec in all three major coronary arteries. Angiography-derived pullback FFR was derived from the angiogram and compared with invasive FFR pullback curve. <h3>Results</h3> Overall, 13634 FFR values were extracted from the FFR pullback curves from 19 HTx patients. The mean age was 60.8 ± 9.10 years, the mean time after transplantation was 5.88 years [IQR 1.10, 12.0]. A total of 29 vessels (19 LAD, 6 LCX, 4 RCA) were analysed. Mean distal vFFR was 0.91 ± 0.05 whereas invasive distal FFR was 0.92 ± 0.07. A good correlation was found between invasive distal FFR and vFFR (r =0.635; p <0.001). The correlation of the pullback tracing was high with a correlation coefficient between vFFR and invasive FFR pullback values of 0.72 (95% CI 0.71 to 0.73, p <0.001) (<b>Figure A</b>). The mean difference between vFFR and invasive FFR pullback values was -0.02 with 0.03 of SD (limits of agreements -0.08 to 0.04; <b>Figure B</b>). <h3>Conclusion</h3> In HTx patients coronary angiography-derived FFR correlates well with invasively measured wire-derived FFR. Angiography-derived FFR could be used as a novel diagnostic tool to quantify the functional severity of graft vasculopathy.