Clinical Use of Coronary CTA-Derived FFR for Decision-Making in Stable CAD

Abstract

Objectives: The goal of this study was to assess the real-world clinical utility of fractional flow reserve (FFR) derived from coronary computed tomography angiography (FFR_CT) for decision-making in patients with stable coronary artery disease (CAD).

Background: FFR_CT has shown promising results in identifying lesion-specific ischemia. The real-world feasibility and influence on the diagnostic work-up of FFR_CT testing in patients suspected of having CAD are unknown.

Methods: We reviewed the complete diagnostic work-up of nonemergent patients referred for coronary computed tomography angiography over a 12-month period at Aarhus University Hospital, Denmark, including all patients with new-onset chest pain with no known CAD and with intermediate-range coronary lesions (lumen reduction, 30% to 70%) referred for FFR_CT. The study evaluated the consequences on downstream diagnostic testing, the agreement between FFR_CT and invasively measured FFR or instantaneous wave-free ratio (iFR), and the short-term clinical outcome after FFR_CT testing.

Results: Among 1,248 patients referred for computed tomography angiography, 189 patients (mean age 59 years; 59% male) were referred for FFR_CT, with a conclusive FFR_CT result obtained in 185 (98%). FFR_CT was ≤0.80 in 31% of patients and 10% of vessels. After FFR_CT testing, invasive angiography was performed in 29%, with FFR measured in 19% and iFR in 1% of patients (with a tendency toward declining FFR-iFR guidance during the study period). FFR_CT ≤0.80 correctly classified 73% (27 of 37) of patients and 70% (37 of 53) of vessels using FFR ≤0.80 or iFR ≤0.90 as the reference standard. In patients with FFR_CT >0.80 being deferred from invasive coronary angiography, no adverse cardiac events occurred during a median follow-up period of 12 (range 6 to 18 months) months.

Conclusions: FFR_CT testing is feasible in real-world symptomatic patients with intermediate-range stenosis determined by coronary computed tomography angiography. Implementation of FFR_CT for clinical decision-making may influence the downstream diagnostic workflow of patients. Patients with an FFR_CT value >0.80 being deferred from invasive coronary angiography have a favorable short-term prognosis.

Keywords: computed tomography angiography; coronary angiography; coronary artery disease; fractional flow reserve.