Psoas Muscle Area and Quality Are Independent Predictors of Survival in Patients Treated for Abdominal Aortic Aneurysms

Abstract

Sarcopenia is associated with mortality after abdominal aortic aneurysm (AAA) repair. The reliability of computed tomography (CT) core muscle areas and quality-that is, densities and their association with postoperative survival in patients undergoing AAA treatment-were retrospectively studied. Psoas muscle area (PMA) and multifidus area and psoas muscle density (PMD) and multifidus density were measured from CT images and analyzed to lean values. Results were standardized by z-scoring. Measurement reliability was ascertained using intraclass correlation coefficient analysis (3 independent observers). Clinical data were collected from an institutional database and the hospital's patient record database. The study included 301 patients (89% male, mean age 74.4years, endovascular treatment 73.1%, rupture 7.6%). Median duration of follow-up was 2.70 (interquartile range 3.54) years and mortality 31.2%. Age, female gender, and body mass index were associated with PMA, PMD, and lean psoas muscle area (LPMA). L3 left PMD, total psoas muscle density, right and left LPMA, lean total psoas muscle area (LTPMA), and L2 right LPMA and LTPMA (hazard ratio 0.74-0.78 per 1 standard deviation, P<0.05 to P<0.01) were independently associated with improved survival in multivariable analysis. L2-L3 PMD and LPMA are reliable, feasible, and independent predictors of mortality in patients treated for AAA. For every standard deviation increase in these standardized z-score muscle parameters, there was a 22%-26% decrease in the probability of death during follow-up.