Preoperative sarcopenia is associated with late mortality after off-pump coronary artery bypass grafting

OBJECTIVES We investigated the association between sarcopenia (a marker of frailty) and outcomes after coronary artery bypass grafting (CABG). METHODS This study included 304 patients who underwent elective isolated off-pump CABG at our hospital between October 2008 and August 2013. Psoas muscle area was measured on preoperative computed tomography scans. Sarcopenia was defined as the lowest sex-specific quartile of the psoas muscle area index (the psoas muscle area normalized for height). Patients were categorized into a sarcopenia group (76 patients) and a non-sarcopenia group (228 patients). Patients in the sarcopenia group were older and showed a lower body mass index, lower serum haemoglobin and albumin levels and lower prevalence of dyslipidaemia but higher prevalence of renal dysfunction and peripheral artery disease. The mean follow-up period was 4.5 ± 2.3 years. RESULTS The cut-off values for sarcopenia were psoas muscle area index 215 and 142 mm2/m2 in men and women, respectively. No intergroup difference was observed in the in-hospital mortality and morbidity rates. After risk adjustment using inverse probability weighting analysis, late mortality rates were significantly higher in the sarcopenia group than in the non-sarcopenia group (P = 0.022). Multivariable analysis showed that preoperative sarcopenia was an independent predictor of late mortality (hazard ratio 4.25, 95% confidence interval 2.18–8.28; P < 0.001). Preoperative sarcopenia was not associated with major adverse cardiac and cerebrovascular events during follow-up. CONCLUSIONS Preoperative sarcopenia (assessed by psoas muscle area index) was associated with late mortality after CABG and effectively predicts postoperative prognosis.