Abstract 16623: Extra-Cellular Volume Fraction Analysis on Cardiac CT is Useful for Predicting the Prognosis of Hypertrophic Cardiomyopathy

Abstract

Introduction: Extra-Cellular volume fraction (ECV) analysis on MRI helps predict ventricular arrhythmia in hypertrophic cardiomyopathy (HCM). But the performance of cardiac MRI takes time, and there are also several contraindications. Cardiac CT is more versatile than cardiac MRI and is also helpful in screening coronary artery disease. We investigated the usefulness of ECV analysis on CT for the prognosis of HCM.Aim: To determine the utility of ECV analysis on CT to predict the prognosis in patients with HCM. Methods: Eighty-five HCM patients who underwent cardiac CT from December 2008 to March 2022 were analyzed. Left ventricular (LV) ECV (LV-ECV) on CT was measured, and we investigated the relationship between LV-ECV on CT and the major adverse cardiac events (MACEs) (cardiac death, fatal arrhythmia, and heart failure hospitalization) after CT. Results: All patients were followed for 69 ± 58 months after cardiac CT and 14 patients (16%) had MACEs. They had a significantly higher LV-ECV and lower ejection fraction (LVEF) than those without MACEs(42.4 ± 8.4% vs. 34.0 ± 7.0%, P=0.003, and (56.7 ± 11.8% vs. 66.7 ± 7.0%, P=0.011). The percentage of dilated phase HCM was significantly higher in the patients with MACEs than those without MACEs (21% vs 0%, p=0.003). LV-ECV was the only significant predictor of MACEs based on the multivariate analysis by Cox proportional hazard model (hazard ratio 1.13, 95% confidence interval 1.06-1.21). The optimal threshold of LV-ECV to predict MACEs was 37.59% based on the receiver operating characteristic analysis. The sensitivity and specificity of LV-ECV to predict MACEs were 79% and 75% at the best cut-off, and the area under the curve was 0.78 (Figure A). The patients with LV-ECV ≥ 37.59% (29 patients) had significantly higher MACEs than those with LV-ECV < 37.59% during the follow-up periods (P <0.001) (Figure B). Conclusion: ECV analysis on CT helped predict MACEs in HCM cases.