Computed Tomography -Defined Sarcopenia is Associated with Long-Term Survival among Patients Undergoing Open Thoracic Aortic Reconstruction.

Background and objective: As markers of sarcopenia, psoas muscle areas and indexes measured from computed tomography images have been found to predict long-term mortality in cardiothoracic as well as other surgical cohorts. Our objective was to investigate the association between psoas muscle status, taking into account muscle density in addition to area, and survival among patients undergoing open thoracic aortic reconstruction. Methods: This was a retrospective registry study of a total of 451 patients treated with open surgery for thoracic aortic pathology. Psoas muscle area and density were measured from preoperative computed tomography images at the L3 and L4 lumbar levels. In addition, lean psoas muscle area was calculated by averaging sex-specific values of psoas muscle area and density. The association between mortality and psoas muscle status was analyzed with adjusted Cox-regression analysis. Results: The median age of the study population was 63 (interquartile range (IQR): 53- 70) years. The majority were male (74.7%, n = 337) and underwent elective procedures (58.1% n = 262). Surgery of the ascending aorta was carried out in 90% of the patients, and 15% ( n = 67) had concomitant coronary artery bypass surgery. Aortic dissection was present in 34.6% ( n = 156) patients. Median follow-up time was 4.3 years (IQR: 2.2-7.4). During the follow- up, 106 patients (23.5%) died, with 55.7% of deaths occurring within the first four postoperative weeks. Psoas muscle parameters were not associated with perioperative mortality, but significant independent associations with long-term mortality were observed for psoas muscle area, density, and lean psoas muscle area with hazard ratios (HRs) of 0.63 (95% confidence interval (CI): 0.45-0.88), 0.62 (95% CI: 0.46-0.83), and 0.47 (95% CI: 0.32-0.69), respectively ( all per 1-SD increase). Conclusions: Psoas muscle sarcopenia status is associated with long-term mortality after open thoracic aortic surgery.