The Role of Low Core Muscle Mass in Survival of Patients with Abdominal Aortic Aneurysm: A Prognostic Factor Review and Meta-analysis of Time-to-event Data

Abstract

Introduction: Patients with abdominal aortic aneurysm (AAA) often present with a significant burden of comorbidities and are likely to be frail. Low psoas muscle mass, a surrogate marker of sarcopenia and indicator of frailty, is associated with increased perioperative mortality and morbidity. Recent evidence has linked low psoas muscle mass with medium-term outcomes after AAA repair. We conducted a review of the literature to investigate the prognostic role of low skeletal muscle mass in survival of patients with AAA undergoing open or endovascular aneurysm repair (EVAR). Methods: We conducted a review of the literature in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (registration number: CRD42018107793). The prognostic factor of interest was degenerative loss of core skeletal muscle. We performed a time-to-event data meta-analysis for all-cause mortality using the inverse-variance method and reported the results as summary hazard ratio (HR) and 95% confidence interval (CI). We calculated pooled estimates of peri-operative outcome data using the odds ratio (OR) or risk difference (RD) and 95% CI. We applied random-effects models of meta-analysis. Results: Seven observational cohort studies reporting a total of 1440 patients (264 with low skeletal muscle mass) were eligible for quantitative synthesis. Patients with low skeletal muscle mass had a significantly higher hazard of mortality than those without low skeletal muscle mass (HR 1.66, 95% CI 1.15 - 2.40, P=0.007). Subgroup analysis including only patients who underwent EVAR showed a marginal survival benefit for patients without low skeletal muscle mass (HR 1.86, 95% CI 1.00 - 3.43, P< =0.05). Meta-analysis of two studies found no significant difference inperi-operative mortality (RD 0.04, 95% CI -0.13 - 0.21) and morbidity (OR 1.58, 95% CI 0.90 - 2.76, P=0.11) between patients with and without low skeletal muscle mass. Conclusion: There is a significant and clinically relevant link between low core skeletal muscle mass and mortality in patients undergoing AAA repair. Prospective studies validating the use of body composition for risk prediction after aortic surgery are required before this tool can be used to support decision making and patient selection. Disclosure: Nothing to disclose