Psoas Muscle Area and All-Cause Mortality After Transcatheter Aortic Valve Replacement: The Montreal-Munich Study

Background: Psoas muscle area (PMA) is a novel measure of frailty that can be efficiently measured from computed tomography images to help predict risk in older adults referred for transcatheter aortic valve replacement (TAVR). The objective of this study was to determine if PMA would be incrementally predictive of mortality and morbidity after TAVR. Methods: The pre-TAVR computed tomography scans of 208 consecutive patients at 2 hospitals in Montreal and Munich were analyzed to measure the cross-sectional area of the left and right psoas muscles on a single axial slice at the level of L4. The primary outcome was all-cause mortality assessed according to sex-stratified Cox regression models adjusted for the Society of Thoracic Surgeons predicted risk of mortality. Results: The mean age was 80.7 ± 6.8 years with 55% women and a total of 57 deaths over a mean follow-up of 504 days. PMA was lower in nonsurvivors compared with survivors among women (12.9 vs 14.5 cm²; P = 0.047) but not men (21.7 vs 22.4 cm²; P = 0.50). The association between PMA and all-cause mortality in women persisted after adjustment for Society of Thoracic Surgeons risk (hazard ratio, 0.88 per cm²; 95% confidence interval, 0.78-0.99). An association between PMA and bleeding complications was seen in men (odds ratio, 0.78; 95% confidence interval, 0.62-0.97). Sensitivity analyses with PMA normalized to body mass index yielded similar results. Conclusions: This study has shown that PMA is a marker of frailty associated with midterm survival in women who undergo TAVR. Further research is warranted to pursue PMA as a prognostic marker and therapeutic target in this vulnerable population.