Psoas muscle quantified muscle status and long-term mortality after cardiovascular interventions

Background: Psoas muscle area (PMA) and density (PMD) measured using computed tomography are potential surrogates for evaluating sarcopenia-related mortality risk among patients undergoing cardiovascular interventions. However, the optimal measurement method remains unclear. Methods: A retrospective registry study of three observational cohorts comprising 2248 patients undergoing cardiovascular interventions (n = 828 for abdominal aortic aneurysms, n = 983 transcatheter aortic valve implantations, and 437 patients undergoing open surgery for thoracic aortic and aortic valve pathology) was conducted. Age-independent associations between mortality and PMA, PMD, PMA indexed to height or body surface area, and the combination of PMA and PMD (lean PMA) were meta-analyzed (using individual participant data) across cohorts after sex stratification with median follow-up times ranging from three to five years for each cohort. Results: In the meta-analysis, psoas muscle measurements were significantly associated with mortality among men (p < 0.05), with high heterogeneity in the associations across all cohorts. There was very little difference in the association between PMA and PMD and mortality (HR 0.83, 95% CI 0.69-0.99, p = 0.002; HR 0.85, 95% CI 0.77-0.94, p = 0.041 for one SD increase in PMA and PMD in the random effects model). Combining PMA and PMD into one composite variable by multiplying their values together showed the most robust association in terms of the magnitude of the effect size in men (HR, 0.77; 95% CI 0.73-0.87, p < 0.001). Indexing PMA to body size did not result in any significant differences in this association. Among women, psoas muscle measurements were not associated with long-term mortality in this meta-analysis. Conclusions: Different psoas muscle measurements were significantly and very similarly associated with mortality among men but not among women. No single measurement stands out, although combining PMA and PMD seems to be a slightly stronger estimate in terms of effect size and should be considered in further studies.