Abstract 4145958: Quantification of Sarcopenia in Chest Computed Tomography Prognosticates Cardiac Surgery Outcome

Background: Sarcopenia is an objective and comprehensive marker of frailty and an important predictor of outcomes after cardiac surgery. Its utility is challenging due to difficulty in its assessment. Hypothesis: We hypothesize that sarcopenia defined as pectoralis major cross-sectional area (PMA) from CT Chest is a useful predictor of cardiac surgery outcomes. Aim: The aim of this study is to develop Gender Specific Cut-off Points for PMA as a marker for sarcopenia and to evaluate the associations between sarcopenia and post-operative cardiac surgery outcomes. Methods: This study includes 237 subjects with pre-operative CT Chest scans who underwent any Cardiac Surgery involving sternotomy from 2019 to 2023 at the Townsville University Hospital, Australia. The Pectoralis Major Muscle Area, Density and Thickness measurements were performed at the level of 4th thoracic vertebra in Axial view. The sarcopenia cut-off value was defined as the lowest sex-specific quartile in PMA. Intra and post-operative outcomes up to 30-days, were collected. Results: The Cut-off values for PMA were set at 1045mm 2 for males and 609mm 2 for females, with 59 subjects meeting the criteria for sarcopenia. Sarcopenic patients required longer hospitalization (10.8±6.93 vs 8.37±5.26 days; P=0.006), longer intubation and stay in ICU, and experienced more post-operative complications within the first 30 days after surgery (p=0.002). Post-operative mortality was similar in both groups. Logistic regression analysis revealed that sarcopenia is associated with increased risk in days of extended hospital stays (OR=5.08, 95% CI: 2.35-10.96, p<0.001), ICU stays (OR=3.16, 95% CI:1.54-6.50, p<0.002),and intubation (OR=2.49, 95% CI:1.09-5.67, p=0.031). Moreover, the Receiver Operating Characteristic (ROC) analysis showed that muscle thickness displayed a higher degree of accuracy than density for assessment of sarcopenia and achieved a sensitivity of 80% and specificity of 70% at cut-off values of 12.2mm in males and 8.1mm in females, with an area under the curve (AUC) of 0.85. Conclusion: Patients undergoing cardiac surgery with pre-op CT Chest can be assessed for sarcopenia with PMA or simply thickness of pectoralis major muscle. Sarcopenia defined based on CT Chest PMA is a significant predictor of post-operative outcomes in cardiac surgery patients, including longer hospitalization, ICU stay, and intubation time, as well as increased risk of post-operative complications within the first 30 days after surgery.