Effects of sarcopenia on postoperative recovery in elderly patients after cardiac surgery with cardiopulmonary bypass.

Background: Few studies have assessed sarcopenia identified by erector spinae muscle (ESM) using thoracic computed tomography (CT) before cardiac surgery. We aimed to explore the relationship between sarcopenia evaluated via ESM and poor outcomes following cardiac surgery with cardiopulmonary bypass (CPB) in elderly patients.

Methods: 268 patients older than 65 years who underwent cardiac surgery with CPB at our institution in 2020 were included in the retrospective, single center, cohort study. Preoperative chest CT scans were used to measure the cross-sectional areas of the ESM (ESM_CSA), which were then adjusted for body surface area (BSA) to determine the muscle mass index. Patients were categorized into sarcopenia and non-sarcopenia groups based on ESM_CSA/BSA scores, and their short- and long-term clinical outcomes were compared.

Results: The ESM_CSA/BSA detected sarcopenia in 51.1% of patients. Patients with sarcopenia had significantly extended durations of stay in both the intensive care unit and the hospital compared to those without sarcopenia. Furthermore, the incidence of major adverse events was significantly higher in the sarcopenia group compared to the non-sarcopenia group (15.3% vs. 32.1%, P < 0.001). Furthermore, multivariate logistic regression analysis demonstrated that sarcopenia (OR 2.457, 95% CI 1.178-5.126, P = 0.017) independently predicted the risk of postoperative complications after adjusting for gender, preoperative nutritional status, serum albumin, estimated glomerular filtration rate, creatinine, white blood cell count, lymphocytes, type of surgery, surgical time, and aortic cross-clamp time. Kaplan-Meier survival analysis revealed a statistically significant difference in overall mortality between groups (log-rank P = 0.011). The Cox proportional hazards model identified preoperative sarcopenia as an independent risk factor for long-term mortality (HR, 2.132; 95% CI 1.144-3.972, P = 0.017).

Conclusion: Our study identified preoperative sarcopenia, assessed via ESM muscle mass on chest CT, as an independent predictor of postoperative complications and long-term overall mortality in elderly cardiac surgery patients with CPB.