Abstract 4138602: Effect of Left Ventricular Ejection Fraction On Computed Tomography-Derived Fractional Flow Reserve Diagnostic Accuracy For Significant Coronary Artery Disease

Background: Coronary Computed Tomography Angiography (CCTA) and CT-derived fractional flow reserve (CT-FFR) accurately assess the severity of coronary artery disease. However, the diagnostic accuracy of CT-FFR in patients with low left ventricular ejection fraction (LVEF) is unknown. Goal: Describe the per-vessel diagnostic performance of CT-FFR to detect significant coronary disease in patients with normal and reduced LVEF by echocardiogram. Methods: This was a retrospective study of 441 patients who underwent CCTA and CT-FFR at the UMass Memorial Health System between 2020 and 2023. Those with echocardiogram and invasive coronary angiography were analyzed and divided in two groups based on two-dimensional LVEF: those with LVEF < 55%, and with LVEF ≥ 55%. We excluded those with prior coronary stents, incomplete CCTA, CT-FFR data due to artifacts, or poor-quality echocardiographic images. CT-FFR ≤ 0.8 was considered abnormal. Significant coronary disease by invasive angiography (reference standard) was defined as lumen stenosis ≥ 70% (left main ≥ 50%), or abnormal physiologic characteristics by FFR, resting full-cycle ratio, or instantaneous wave-free ratio. Results: 222 coronary vessels (102 patients) were analyzed. Of 102 vessels (44%) with significant coronary artery disease, 55 (53.9%) were treated with percutaneous coronary intervention, and 25 (24.5%) with coronary artery bypass grafting. Overall, CT-FFR sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 86.7% (95%CI 78.3-92.7), 75.0% (95%CI 66.4-82.3), 73.2% (95%CI 66.6-78.9), 87.7% (95%CI 81.0-92.3), and 80.1% (95%CI 74.3-85.2), respectively. 37 vessels corresponded to patients with LVEF < 55%, and 185 to those with LVEF ≥ 55%. Diagnostic accuracy in both groups is seen in table 1. Conclusions: Low-normal and reduced LVEF adversely affects the diagnostic performance of CT-FFR, by reducing sensitivity, and slightly increasing specificity.