Effect of Low Skeletal Muscle Mass on Post-operative Survival of Patients With Abdominal Aortic Aneurysm: A Prognostic Factor Review and Meta-Analysis of Time-to-Event Data

Abstract

WHAT THIS PAPER ADDSPatients with abdominal aortic aneurysm (AAA) often present with a significant burden of comorbidities and are likely to be frail. Low skeletal muscle mass, a surrogate of sarcopenia and indicator of frailty, has been associated with increased mortality and morbidity after surgery. The prognostic role of low skeletal muscle mass in the survival of patients with AAA undergoing open or endovascular repair was investigated by conducting a metaanalysis of bibliographic data. Patients with low skeletal muscle mass had a significantly higher risk of mortality. Further research is required to validate the use of body composition for risk prediction after aortic surgery.Objective/Background: Low psoas muscle mass is associated with increased mortality and morbidity after surgery. Recent evidence has linked low psoas muscle mass with survival after abdominal aortic aneurysm (AAA) repair. The aim of this study was to investigate the prognostic role of low skeletal muscle mass in survival of patients with AAA undergoing open or endovascular aneurysm repair (EVAR). Methods: A review of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO registration number: CRD42018107793). The prognostic factor of interest was degenerative loss of skeletal muscle. A time-to-event data meta-analysis was performed for all cause mortality using the inverse variance method and the results were reported as summary hazard ratio (HR) and 95% confidence interval (CI). Pooled estimates of peri-operative outcome data were calculated using the odds ratio (OR) or risk difference (RD) and 95% CI. Random-effects models of meta-analysis were applied. Results: Seven observational cohort studies reporting a total of 1,440 patients 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 1.15e2.40; p ¼ .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 1.00e3.43; p ¼ .05). Meta-analysis of two studies found no significant difference in peri-operative mortality (RD 0.04, 95% CI e0.13 to 0.21) and morbidity (OR 1.58, 95% CI 0.90e2.76; p ¼ .11) between patients with and without low skeletal muscle mass. Conclusion:There is a significant link between low 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.

Pre-operative Low Muscle Mass Is Associated with Mortality Rate after Elective Abdominal Aortic Aneurysm Repair

“…Measurement of skeletal muscle mass on pre-operative computed tomography (CT) as a proxy for sarcopenia (defined by low muscle mass, strength, and performance) may improve risk stratification. 3 This single centre retrospective cohort study investigated the association between low muscle mass and survival after elective AAA surgery. The study protocol was approved by the local review board of the ethics committee (Medical research Ethics Committee United, number R&D/ Z19.005).…”

“…4 Total cross sectional muscle area (CSMA) analysis was performed at the level of the third lumbar vertebra. 3 The inner and outer contour of the CSMA was traced manually and the tissue within the threshold of À30 to þ150 Hounsfield Units (HU) was selected. Average tracing time was 5 min per patient.…”

“…To analyse SMI, patients were divided into tertiles, based on SMI, and classified as low (lowest tertile) or normal muscle mass (middle and highest tertile). 3 Separate sex specific cut off values were determined. The association between low muscle mass and mortality rate was analysed with Cox proportional hazard models and adjusted for the Vascular-POSSUM physiology score (comorbidities), age, and surgical approach, resulting in a hazard ratio (HR) and 95% confidence intervals.…”

“…These results confirmed that low muscle mass was associated with lower survival, irrespective of the procedure and comorbidities. 3 This study addresses several important issues. First, after adjustment for age, comorbidity, and surgical approach, low muscle mass was a significant risk factor for overall mortality after AAA surgery.…”

Re. “Effect of Low Skeletal Muscle Mass on Post-operative Survival of Patients With Abdominal Aortic Aneurysm: A Prognostic Factor Review and Meta-Analysis of Time to Event Data”

“…Firstly, we would like to emphasise that our goal was to assess the skeletal muscle mass (or a surrogate marker thereof), not sarcopenia, as a prognostic factor. 1 We tried to be consistent with correct terminology despite source Eur J Vasc Endovasc Surg (2019) 58, 940e942…”