Diagnostic and Clinical Value of FFRCT in Stable Chest Pain Patients With Extensive Coronary Calcification

The influence of extensive coronary calcifications on the diagnostic and prognostic value of coronary computed tomography angiography-derived fractional flow reserve (FFRCT) has been scantily investigated.The purpose of this study was to investigate the diagnostic and short-term role of FFRCT in chest pain patients with Agatston score (AS) >399.This was a prospective multicenter study of 260 stable patients with suspected coronary artery disease (CAD) and AS >399. FFRCT was measured blinded by an independent core laboratory. All patients underwent invasive coronary angiography (ICA) and FFR if indicated. The agreement of FFRCT ≤0.80 with hemodynamically significant CAD on ICA/FFR (≥50% left main or ≥70% epicardial artery stenosis and/or FFR ≤0.80) was assessed. Patients undergoing FFR had colocation FFRCT measured, and the lowest per-patient FFRCT was registered in all patients. The association among per-patient FFRCT, coronary revascularization, and major clinical events (all-cause mortality, myocardial infarction, or unstable angina hospitalization) at 90-day follow-up was evaluated.Median age and AS were 68.5 years (IQR: 63-74 years) and 895 (IQR: 587-1,513), respectively. FFRCT was ≤0.80 in 204 patients (78%). Colocation FFRCT (n = 112) showed diagnostic accuracy, sensitivity, and specificity to identify hemodynamically significant CAD of 71%, 87%, and 54%. The area under the receiver-operating characteristics curve (AUC) was 0.75. When using the lowest FFRCT (n = 260), per-patient accuracy, sensitivity, and specificity were 57%, 95%, and 32%, respectively. The AUC was 0.84. A total of 85 patients underwent revascularization, and FFRCT was ≤0.80 in 96% of these. During follow-up, major clinical events occurred in 3 patients (1.2%), all with FFRCT ≤0.80.Most patients with AS >399 had FFRCT ≤0.80. Using ICA/FFR as the reference revealed a moderate diagnostic accuracy of colocation FFRCT. Compared with the lowest per-patient FFRCT, colocation FFRCT measurement improved diagnostic accuracy and specificity. The 90-day follow-up was favorable with few coronary revascularizations and no major clinical events occurring in patients with FFRCT >0.80. (Use of FFR-CT in Stable Intermediate Chest Pain Patients With Severe Coronary Calcium Score [FACC]; NCT03548753).