Clinical Research Sarcopenia in Patients Undergoing Lower Limb Bypass Surgery is Associated with Higher Mortality and Major Amputation Rates

Background: Sarcopenia is adversely associated with survival in several diseases. Vasculopathy is often associated with multimorbidity and consequent deconditioning with poor long-term outcomes. This study examined the impact of sarcopenia on clinical outcome in patients with and without critical limb-threatening ischaemia who underwent infrainguinal bypass surgery. Methods: All patients undergoing infra-inguinal surgical revascularisation in 2016-2018 were retrospectively reviewed. Sarcopenia was defined as a skeletal muscle area at the L3 vertebral level (defined as L3 muscle area < 114cm 2 for men or < 89.8cm 2 for women) on CT angiography. The primary outcome was overall survival by analysed by time to event analysis. Secondary outcomes included ipsilateral major lower-limb amputation, length of hospital stay, myocardial infarction and surgical-site infection. Results: A total of 116 patients with a mean age of 66.9 years were included, with a mean followup of 21 months. 14 (12%) of patients were sarcopenic; there were more patients with diabetes (40% vs 7%) in the sarcopenic group, p = 0.018. Age, gender, Rutherford grade at presentation, other co-morbidities, other laboratory tests, conduit material and Rutherford grade at presentation were similar in those with and without sarcopenia and were statistically insignificant upon testing. Overall survival was worse for sarcopenic patients (Log Rank P = 0.001) and Hazard Ratio for death 5.8; 95%CI 1.8-19.1; P = 0.001. Major lower-limb amputation occurred more frequently in patients with sarcopenia (7/14 [50%] vs 23/102 [23%]; P = 0.046). There was no difference in other secondary outcomes including rates of graft occlusion, myocardial infarction, surgical site infection and length of stay. Adding SMA measurement to a multivariate generalised linear model including age, sex, diabetes, and haemoglobin improved the AUROC from 0.75-0.85. Conclusion: In this cohort of patients undergoing vascular surgery, sarcopenia defined using L3 muscle area was significantly associated with overall mortality and major lower-limb amputation.