Noninvasive FFR Derived From Coronary CT Angiography: Management and Outcomes in the PROMISE Trial

Objectives: The purpose of this study was to determine whether noninvasive fractional flow reserve derived from computed tomography (FFR) predicts coronary revascularization and outcomes and whether its addition improves efficiency of referral to invasive coronary angiography (ICA) after coronary computed tomography angiography (CTA).

Background: FFR may improve the efficiency of an anatomic CTA strategy for stable chest pain.

Methods: This observational cohort study included patients with stable chest pain in the PROMISE (PROspective Multicenter Imaging Study for Evaluation of Chest Pain) trial referred to ICA within 90 days after CTA. FFR was measured at a blinded core laboratory, and FFR results were unavailable to caregivers. We determined the agreement of FFR (positive if ≤0.80) with stenosis on CTA and ICA (positive if ≥50% left main or ≥70% other coronary artery), and predictive value for a composite of coronary revascularization or major adverse cardiac events (death, myocardial infarction, or unstable angina). We retrospectively assessed whether adding FFR ≤0.80 as a gatekeeper could improve efficiency of referral to ICA, defined as decreased rate of ICA without ≥50% stenosis and increased ICA leading to revascularization.

Results: FFR was calculated in 67% (181 of 271) of eligible patients (mean age 62 years; 36% women). FFR was discordant with stenosis in 31% (57 of 181) for CTA and 29% (52 of 181) for ICA. Most patients undergoing coronary revascularization had an FFR of ≤0.80 (91%; 80 of 88). An FFR of ≤0.80 was a significantly better predictor for revascularization or major adverse cardiac events than severe CTA stenosis (HR: 4.3 [95% confidence interval [CI]: 2.4 to 8.9] vs. 2.9 [95% CI: 1.8 to 5.1]; p = 0.033). Reserving ICA for patients with an FFR of ≤0.80 could decrease ICA without ≥50% stenosis by 44%, and increase the proportion of ICA leading to revascularization by 24%.

Conclusions: In this hypothesis-generating study of patients with stable chest pain referred to ICA from CTA, an FFR of ≤0.80 was a better predictor of revascularization or major adverse cardiac events than severe stenosis on CTA. Adding FFR may improve efficiency of referral to ICA from CTA alone.