(IP025) Sarcopenia of the Psoas Major Muscles Risk Stratifies Patients Between Endovascular and Open Repair of Thoracoabdominal Aortic Aneurysm

Objectives: Sarcopenia, which can be evaluated by the cross sectional area of the psoas muscles, is associated with higher mortality for endovascular and open abdominal aortic aneurysm repair. Previous authors have used sarcopenia as a proxy for patient frailty, thus increasing the likelihood of patient mortality. This study aims to assess the association between the normalized total psoas muscle area (nTPA) and mortality following endovascular and open repair of thoracoabdominal aortic aneurysms (TAAAs).

Methods: A retrospective cohort of patients undergoing elective TAAA repair from 2007-2023 with available computed tomography (CT) imaging was selected. Psoas major muscle cross sectional area was measured bilaterally and normalized by patients’ body mass index (BMI) to produce nTPA values. Receiver operator characteristic curves were generated using patient mortality data and nTPA values to define a threshold for sarcopenia. Kaplan-Meier survival curves were generated to assess overall differences in survival between open and endovascular patients stratified by sarcopenia status. Univariable and multivariable models were used to investigate the association of patient comorbidity and procedure modality on overall survival.

Results: In total, 125 elective TAAA patients were included in the study. Sixty four (51.2%) had open and 61 (48.8%) underwent endovascular repair. Median nTPA values for open and endovascular cohorts were 67.7 (IQR=55.4-84.0) (mm^2*m^2)/kg and 65.4 (IQR=47.9-79.6) (mm^2*m^2)/kg respectively. Sarcopenia was defined as nTPA < 50.56 (mm^2*m^2)/kg (AUC=0.63,Specificity=80.0%,Sensitivity=28.6%,P=0.03)(Figure 1). Kaplan-Meier analysis demonstrated significant differences in survival between the treatment modalities stratified by sarcopenia status according to a log-rank test (P=0.04)(Figure 2). Post-hoc comparisons demonstrated a significant decrease in survival proportion within the open cohort, with sarcopenic patients having significantly lower survival than non-sarcopenic patients (P=0.02). The multivariable cox proportional hazards regression demonstrated that sarcopenia status (HR:4.2,95%CI:1.2-12.7,P=0.01) and chronic kidney disease (HR:2.5,95%CI:1.1-5.1,P=0.02) increased the risk of mortality throughout the study period. Relative to sarcopenic patients undergoing open procedures, those undergoing endovascular procedures saw a decreased risk of mortality according to the cox model (HR:0.11,95%CI:0.02-0.69,P=0.02).

Conclusions: Patients with sarcopenia of the psoas major muscles have a higher risk of mortality undergoing open repair of TAAAs than those who underwent endovascular repair. Independent of procedure modality, sarcopenic patients were significantly more likely to die throughout the study period than non-sarcopenic patients. This risk was nearly twice that of patients with chronic kidney disease.