Abstract 13539: CT-Derived Fractional Flow Reserve in Patients With Non-ST Elevation Myocardial Infarction

Abstract

Introduction: In patients with non-ST Elevation Myocardial Infarction (NSTEMI), coronary CTA has high diagnostic accuracy to diagnose obstructive coronary artery disease (CAD). The value of CT-derived fractional flow reserve (FFRCT) in NSTEMI patients is unclear. Hypothesis: In acute chest pain (ACP) patients diagnosed with an NSTEMI, FFRCT is feasible, safe and adjudicates the need for immediate revascularization. Methods: In ACP patients with NSTEMI and no prior coronary artery disease, those undergoing coronary CTA with FFRCT were compared to those having CTA alone for the composite major adverse cardiac event (MACE) endpoint of death, nonfatal myocardial infarction, unplanned percutaneous (PCI) or surgical (CABG) revascularization over 2 years. NSTEMI was defined as peak troponin I levels ≥ 0.04 ng/mL. FFRCT ≤ 0.80 was considered positive for hemodynamically significant stenosis. Results: From September 2015 to July 2018, 276 ACP patients with NSTEMI (mean age 59 years, 45% female) underwent CTA of which 35 (13%) had FFRCT (14 negative, 21 positive). Of the total, 126 (45.6%) had normal coronaries and 11 (4.0%) were uninterpretable. FFRCT patients were older (p<0.001) with no difference in diabetes (14.3% vs. 14.1%, p=1.0), hypertension (57.1% vs. 49.4%, p=0.391), hyperlipidemia (34.3% vs. 28.2%, p=0.460) and mean troponin I levels (0.49 ± 0.9 ng/mL vs. 1.10 ± 4.58 ng/mL, p = 0.061). All FFRCT patients had >25% stenosis on CTA (100% vs. 42%, p<0.001). Among patients with comparable stenosis on CTA, FFRCT and CTA had equivalent MACE (5.7% vs. 18.5%, p=0.137), with no difference between FFRCT negative and positive patients (Table 1). Conclusions: In this small study, FFRCT did not add incremental value to CTA in patients with NSTEMI across similar stenosis categories with respect to MACE. Larger prospective studies are needed to examine FFRCT in NSTEMI.