CT-derived Pre-treatment Thoracic Sarcopenia is associated with Late Mortality After Thoracic Endovascular Aortic Repair.

Background: Frailty, characterized by physiologic depletion, predicts postoperative morbidity and mortality in vascular surgery patients. CT-derived sarcopenia is a valuable method for objectively staging frailty preoperatively. Purpose: With prior analyses primarily measuring psoas cross-sectional area on CT, we compared a method of measuring thoracic sarcopenia to existing techniques of lumbar sarcopenia and assessed the association with long-term survival and outcomes post-Thoracic Endovascular Aortic Repair (TEVAR). Methods: Prospectively collected data of 217 patients undergoing TEVAR from 2009 to 2012 were reviewed. Thoracic sarcopenia was quantified by measuring total area of the rectus abdominis, latissimus dorsi, intercostal, erector spinae, and external and internal oblique muscles at the T12 vertebral level. Total psoas area at the L3 was used to measure lumbar sarcopenia. Results: 200 patients had preoperative imaging enabling measurements of thoracic sarcopenia, 186 of these patients were also assessed for lumbar sarcopenia. Thoracic sarcopenic patients were older, had lower body mass indices, were more commonly female, and most commonly being treated for aneurysms. Thoracic sarcopenic patients had significantly higher rates of congestive heart failure, hypertension, prior vascular intervention, and TEVAR-related adverse events. Thoracic sarcopenia was associated with significantly higher mortality at 2 and 5 years post-TEVAR (2-year mortality: 19% vs 8%, P = 0.02; 5-year mortality: 31% vs 18%, P = 0.03). Lumbar sarcopenia was not associated with increased mortality at any time point. Patients whose muscle mass degraded over 48-month follow-up did not experience significantly higher rates of adverse events. Conclusions: CT-derived thoracic sarcopenia, but not lumbar sarcopenia, is significantly associated with 5-year mortality post-TEVAR.