Description

Sarcopenia, characterized by the progressive loss of muscle volume and function, is a common and major complication in end-stage liver disease which significantly contributes to adverse outcomes and mortality as well as hampers successful outcomes for treatments such as liver transplant (LT). High resolution image-based techniques have been instrumental in furthering our understanding of body composition in sarcopenia specifically and human health in general. While several methods exist to evaluate body composition, imaging techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI) enable capitalization of images taken as part of standard practice as well as append already clinical examinations with brief sequences tailored for mapping muscle and body composition. Opportunistic application of this imaging-based body composition assessment to patients in a liver transplant context has revealed a high prevalence of sarcopenia (low muscle volume relative to age and sex) and pathological muscle fat infiltration (myosteatosis). Furthermore, a recent long-term (6-years post-LT) MRI-based retrospective study showed associations of myosteatosis to increased graft loss and mortality after transplant.

The combination of MRI-based thigh muscle volume and fat infiltration has been suggested as a more complete description of muscle composition with a stronger link to hospitalization, poor functional activities of daily life, and metabolic co-morbidities in general population and subjects presenting with non-alcoholic fatty liver disease. A recently submit paper explored the predictive power of this combination based on 40 000 participants in the UK biobank and found that the presence of adverse muscle composition, that is the combination of lower-than-expected muscle volume and high muscle fat infiltration, showed to be a strong and independent predictor of all-cause mortality comparable to that of previous cancer diagnosis and smoking. The same MRI-sequence and body composition assessment has successfully been implemented in small pilot studies before and after LT, both within weeks and years after LT, and presented at recent scientific conferences.

There is a lack of knowledge in how to fully identity patients indicted for liver transplant that are of very high risk for adverse outcomes and mortality in standardized fashion. The aim is to use an MRI-based Muscle Assessment Score (MAsS), which includes both muscle volume and fat infiltration, at the transplant candidacy evaluation and other follow-up MRI examinations as clinically indicated, as an objective, standardized, and quantitative measure of muscle health and explore the link between muscle composition and adverse outcomes and mortality. In addition, there are growing numbers of high-risk donor livers, such as presenting with steatosis or exposed to prolonged ischemia time. A co-primary aim is to gather information on the association between transplant recipient muscle composition and donor liver characteristics to one-year post-LT adverse outcomes and mortality.