Evaluation of Fractional Flow Reserve Calculated by Computed Tomography Coronary Angiography in Patients Undergoing TAVR

Overview

The objective of this study is to evaluate the relationship between fractional flow reserve (FFR) derived from coronary computed tomography angiography (FFRct) before transcatheter aortic valve replacement (TAVR) and FFR after TAVR so as to investigate whether FFRct is useful for evaluating myocardial ischemia of severe AS. Furthermore, by measuring the instantaneous wave-free ratio (iFR) which is a physiological diagnostic method of coronary artery stenosis before and after TAVR and comparing iFR (iFR before and after TAVR) and FFR (FFR after TAVR) with FFRct (FFRct before and after TAVR), It also aims to deepen understanding of resting coronary artery physiology in aortic valve stenosis.

This is a single-center, open-label, exploratory, prospective study. Among patients who undergo coronary computed tomography angiography (cCTA) prior to TAVR, those with moderate or severe stenotic lesions will be included in the study. Patients from whom consent is obtained following TAVR will be enrolled in the study. Among patients who undergo TAVR at the Kobe University Hospital from September 2018 to March 2022, those who are found to have moderate or severe stenosis on cCTA performed before surgery and judged to clinically require ischemia evaluation will be included in the study. At the time of pre-TAVR coronary angiogram, iFR (iFR before TAVR) will be measured. The cCTA data collected from patients whose consent is obtained following TAVR will be anonymized and sent to HeartFlow, Inc., where the FFRct（FFRct before TAVR) values will be calculated using their cardiovascular dynamics analysis program. FFR (FFR after TAVR) and iFR (iFR after TAVR) will be measured using a guide wire that is capable of sensing pressure after TAVR is performed. Furthermore, FFRct (FFRct after TAVR) is calculated from cCTA taken after TAVR.