Prognostic implications of psoas muscle area in patients undergoing transcatheter aortic valve implantation

OBJECTIVES: This study sought to assess the incremental prognostic value of the psoas muscle area in patients scheduled for transcatheter aortic valve implantation (TAVI). METHODS: A total of 1076 consecutive patients undergoing TAVI at 2 centres between 2010 and 2017 were prospectively included in this study. Computed tomography-derived cross-sectional area of the psoas muscle was measured at the superior border of the third (L3) and fourth (L4) lumbar vertebra and indexed to body surface area (PMAi) as well as stratified into tertiles. Multivariable logistic regression and Cox regression analyses were performed to investigate the value of PMAi as a predictor of 30-day and cumulative mortality. The incremental prognostic value of PMAi over the Society of Thoracic Surgeons (STS) score was assessed using a net reclassification analysis. RESULTS: The rate of 30-day mortality was 5.8% (n=62). PMAi at the level of L3 [odds ratio 0.082, 95% confidence interval (CI) 0.0110.589; P = 0.013] and L4 (odds ratio 0.049, 95% CI 0.005-0.536; P = 0.013) was independently associated with 30-day mortality. During a median follow-up of 435 days (interquartile range 139-904), 292 patients (27.1%) died. PMAi of L3 (hazard ratio 0.200, 95% CI 0.083-0.482; P < 0.001) and L4 (hazard ratio 0.083, 95% CI 0.029-0.235; P < 0.001) was independently associated with mortality during follow-up. The addition of PMAi to the STS score led to a net reclassification improvement for 30-day and cumulative mortality. CONCLUSIONS: PMAi emerged as a valuable outcome predictor in patients undergoing TAVI. The addition of PMAi to the established STS score led to an increase in its prognostic ability.