A North American Expert Opinion Statement on Sarcopenia in Liver Transplantation

Abstract

Loss of muscle mass and function, or sarcopenia, is a common feature of cirrhosis and contributes significantly to morbidity and mortality in this population. Sarcopenia is a main indicator of adverse outcomes in this population, including poor quality of life, hepatic decompensation, mortality in patients with cirrhosis evaluated for liver transplantation (LT), longer hospital and intensive care unit stay, higher incidence of infection following LT, and higher overall health care cost. Although it is clear that muscle mass is an important predictor of LT outcomes, many questions remain, including the best modality for assessing muscle mass, the optimal cut-off values for sarcopenia, the ideal timing and frequency of muscle mass assessment, and how to best incorporate the concept of sarcopenia into clinical decision making. For these reasons, we assembled a group of experts to form the North American Working Group on Sarcopenia in Liver Transplantation to use evidence from the medical literature to address these outstanding questions regarding sarcopenia in LT. We believe sarcopenia assessment should be considered in all patients with cirrhosis evaluated for liver transplantation. Skeletal muscle index (SMI) assessed by computed tomography constitutes the best-studied technique for assessing sarcopenia in patients with cirrhosis. Cut-off values for sarcopenia, defined as SMI < 50 cm 2 /m 2 in male and < 39 cm 2 /m 2 in female patients, constitute the validated definition for sarcopenia in patients with cirrhosis. Conclusion: The management of sarcopenia requires a multipronged approach including nutrition, exercise, and additional pharmacological therapy as deemed necessary. Future studies should evaluate whether recovery of sarcopenia with nutritional management in combination with an exercise program is sustainable as well as how improvement in muscle mass might be associated with improvement in clinical outcomes.

Physical Function, Physical Activity, and Quality of Life After Liver Transplantation

“…They proposed standardized adoption of the skeletal muscle index (SMI), which is the cross‐sectional area on imaging of muscle at vertebral level L3 normalized to the square of patient height, with sex‐specific cutoffs of 50 and 39 cm 2 /m 2 for North American men and women, respectively. ( 8 ) The slow and incomplete recovery of posttransplant frailty compared with rapid normalization of hepatic synthetic function is mirrored by delayed improvement in measured muscle and bone mass after transplantation. Before transplantation, excess ammonia delivered to skeletal muscle is the central metabolic driver of muscle loss in end‐stage liver disease, mainly by inhibition of the mammalian target of rapamycin pathway that supports muscle protein synthesis.…”

Nutrition in Chronic Liver Disease: A Point‐of‐Care Review

“…4 The type of malnourishment in cirrhosis is primarily a protein-caloric subtype, with sarcopenia being one of the most defining features of malnourishment in patients with advanced decompensated chronic liver disease 5 and is a strong predictor of morbidity and mortality. 6,7 It increases the risk of infections and complications of portal hypertension, including varices, ascites, spontaneous bacterial peritonitis, and hepatorenal syndrome, and is associated with poor wound healing, prolonged hospitalizations, and reduced overall survival. 2,8,9 In 1 study, the risk of these complications was up to 65% in patients with malnutrition compared with only 12% in patients with cirrhosis who were otherwise replete in their nutrition.…”

Barriers to ideal outcomes after pediatric liver transplantation

“…Pilot sarcopenia studies have demonstrated that children with end-stage liver disease have smaller psoas muscle areas on CT abdominal imaging than healthy agematched controls, and that the psoas muscle area does not correlate with weight z-scores nor PELD score. 28,29 Recommendations • Develop validated and objective pediatric tools and non-invasive biomarkers to more fully capture global functional health, nutritional status, and neurocognitive development.…”