Deep Learning-Based 3D CT Body Composition Is Associated With Mortality in Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: Recent advances in artificial intelligence enable fully automated 3-dimensional computed tomography (CT)-based body composition quantification. We investigated whether automated CT-derived thoraco-abdominopelvic body composition measures are associated with mortality after transcatheter aortic valve replacement. METHODS: In this retrospective multicenter study, consecutive patients undergoing transcatheter aortic valve replacement with preprocedural CT imaging were included between 2014 and 2023. A deep learning-based pipeline performed automated 3-dimensional segmentation of thoraco-abdominopelvic noncontrast CT scans to quantify volumes (L/m2) and attenuations (Hounsfield units) of subcutaneous adipose tissue, visceral adipose tissue, muscular adipose tissue, and lean skeletal muscle, indexed to body surface area. Associations with mortality were evaluated using Cox models and Harrell C statistics, adjusting for demographics (age, sex, body mass index) and cardiometabolic risk factors (hypertension, diabetes, chronic renal failure). RESULTS: Among 915 patients (median age, 84 years [interquartile range, 77-90]; 58% men), 160 (17.5%) died over a median follow-up of 22 months (interquartile range, 14-36). Restricted cubic spline analyses demonstrated that lower subcutaneous adipose tissue volume and higher adipose tissue attenuation were associated with increased mortality, whereas higher skeletal muscle volume and attenuation were associated with improved survival. Addition of body composition measures provided incremental discriminatory value beyond demographics and cardiometabolic risk factors (Harrell C, 0.66 versus 0.71; P<0.001). CONCLUSIONS: Automated 3-dimensional CT-derived body composition measures provide independent prognostic information and improve risk stratification for mortality after transcatheter aortic valve replacement. Low subcutaneous adipose tissue volume and higher adipose tissue attenuation identify patients at increased risk, whereas higher skeletal muscle volume and attenuation are associated with lower mortality.