Associations of Sarcopenia and Body Composition Measures with Mortality after Transcatheter Aortic Valve Replacement

Background: Frailty associates with worse outcomes after transcatheter aortic valve replacement (TAVR). Sarcopenia underlies frailty, but the association between a comprehensive assessment of sarcopenia - muscle mass, strength, and performance - and outcomes after TAVR has not been examined. Methods: From a multicenter prospective registry of patients with symptomatic severe aortic stenosis undergoing TAVR, 445 who had a preprocedure computed tomography and clinical assessment of frailty were included. Cross-sectional muscle (psoas and paraspinal) areas were measured on computed tomography and indexed to height. Gait speed and handgrip strength were obtained, and patients were dichotomized into fast versus slow; strong versus weak; and normal versus low muscle mass. As measures of body composition, cross-sectional fat (subcutaneous and visceral) was measured and indexed to height. RESULTS: The frequency of patients who were slow, weak, and had low muscle mass was 56%, 59%, and 42%, respectively. Among the 3 components of sarcopenia, only slower gait speed (muscle performance) was independently associated with increased post-TAVR mortality (adjusted hazard ratio, 1.12 per 0.1 m/s decrease [95% CI, 1.04-1.21]; P=0.004; adjusted hazard ratio, 1.38 per 1 SD decrease [95% CI, 1.11-1.72]; P=0.004). Meeting multiple sarcopenia criteria was not associated with higher mortality risk than fewer. Lower indexed visceral fat area (adjusted hazard ratio, 1.48 per 1 SD decrease [95% CI, 1.15-1.89]; P=0.002) was associated with mortality but indexed subcutaneous fat was not. Death occurred in 169 (38%) patients. CONCLUSIONS: Among patients with symptomatic severe aortic stenosis and comprehensive sarcopenia and body composition phenotyping, gait speed was the only sarcopenia measure associated with post-TAVR mortality. Lower visceral fat was also associated with increased risk pointing to an obesity paradox also observed in other patient populations. These findings reinforce the clinical utility of gait speed as a measure of risk and a potential target for adjunctive interventions alongside TAVR to optimize clinical outcomes.