Myocardial Perfusion Imaging Versus Computed Tomography Angiography-Derived Fractional Flow Reserve Testing in Stable Patients With Intermediate-Range Coronary Lesions: Influence on Downstream Diagnostic Workflows and Invasive Angiography Findings

Abstract

Background: Data on the clinical utility of coronary computed tomography angiography-derived fractional flow reserve (FFR_CT) are sparse. In patients with intermediate (40-70%) coronary stenosis determined by coronary computed tomography angiography, we investigated the association of replacing standard myocardial perfusion imaging with FFR_CT testing with downstream utilization of invasive coronary angiography (ICA) and the diagnostic yield of ICA (rate of no obstructive disease, and rate of revascularization).

Methods and results: This was a single-center observational study of symptomatic patients with suspected coronary artery disease referred to coronary computed tomography angiography between 2013 and 2015. Patients were divided into 3 historical groups based on the adjunctive functional testing approach: myocardial perfusion imaging (n=1332) or FFR_CT "implementation" (n=800) or "clinical use" (n=1391). Propensity score matching was used to estimate the average period effect on outcomes. Patients in the FFR_CT clinical use group versus the myocardial perfusion imaging group were older and had higher pretest probability of obstructive disease. After adjusting for baseline risk characteristics, there was a reduction in downstream ICA utilization (absolute risk difference: -4.2; 95% CI, -6.9 to -1.6; P=0.002). In patients referred to ICA, findings of no obstructive coronary artery disease decreased (-12.8%; 95% CI, -22.2 to -3.4; P=0.008) and rate of coronary revascularization increased (14.1%; 95% CI, 3.3-24.9; P=0.01), as did availability of functional information for guidance of revascularization (27.8%; 95% CI, 11.3-44.4; P<0.001) after clinical adoption of FFR_CT.

Conclusions: Replacing adjunctive myocardial perfusion imaging with FFR_CT testing for functional assessment of intermediate stenosis determined by coronary computed tomography angiography in stable coronary artery disease was associated with less ICA utilization, and a higher ICA diagnostic yield. The findings in this observational study needs confirmation in prospective, randomized trials.

Keywords: computed tomography angiography; coronary artery disease; imaging; positron emission tomography.