Various myosteatosis selection criteria and their value in the assessment of short- and long-term outcomes following liver transplantation

Skeletal Muscle 31P MR Spectroscopy Surpasses CT in Predicting Patient Survival After Liver Transplantation

BACKGROUND

Skeletal muscle alterations are associated with higher mortality and morbidity in patients with liver cirrhosis. Assessing these changes seems to be a promising method for identifying patients at a high risk of poor outcomes following liver transplantation (LT). This is particularly important given the current global shortage of organ donors. However, evidence of the impact of these alterations on the prognosis of patients undergoing LT is inconclusive. The aim of our prospective study was to evaluate the impact of skeletal muscle changes, reflected in sarcopenia, myosteatosis and metabolic changes in the calf muscles, on perioperative outcomes and long-term survival after LT. We also sought to determine the posttransplant evolution of the resting muscle metabolism.

METHODS

We examined 134 adult LT candidates. Of these, 105 underwent LT. Sarcopenia and myosteatosis were diagnosed by measuring the skeletal muscle index and mean psoas muscle radiation attenuation, respectively, which were obtained from computed tomography (CT) scans taken during pretransplant assessment. Additionally, patients underwent 31P MR spectroscopy (MRS) of the calf muscles at rest before LT and 6, 12 and 24 months thereafter. The median follow-up was 6 years.

RESULTS

Patients with abnormal 31P MRS results and CT-diagnosed myosteatosis prior to LT had significantly worse long-term survival after LT (hazard ratio (HR), 3.36; 95% confidence interval (CI), 1.48-7.60; p = 0.0021 and HR, 2.58; 95% CI, 1.06-6.29; p = 0.03, respectively). Multivariable analysis showed that abnormal 31P MR spectra (HR, 3.40; 95% CI, 1.50-7.71; p = 0.003) were a better predictor of worse long-term survival after LT than myosteatosis (HR, 2.78; 95% CI, 1.14-6.78; p = 0.025). Patients with abnormal 31P MR spectra had higher blood loss during LT (p = 0.038), required a higher number of red blood cell transfusions (p = 0.006) and stayed longer in ICU (p = 0.041) and hospital (p = 0.007). Myosteatosis was associated with more revision surgeries following LT (p = 0.038) and a higher number of received red blood cell transfusion units (p = 0.002). Sarcopenia had no significant effect on posttransplant patient survival. An improvement in the resting metabolism of the calf muscles was observed at 12 and 24 months after LT.

CONCLUSIONS

Abnormal 31P MRS results of calf muscles were superior to CT-based diagnosis of myosteatosis and sarcopenia in predicting perioperative complications and long-term survival after LT. Resting muscle metabolism normalized 1 year after LT in most recipients.

Influence of body fat tissue on outcomes in patients undergoing hepatectomy or liver transplantation: a systematic review and meta-analysis

OBJECTIVE

The purpose of this study is to investigate potential associations between body fat composition and postoperative outcomes in patients with hepatectomy or liver transplantation.

METHODS

Three online databases, including Embase, PubMed, and the Cochrane Library, were thoroughly searched for literature describing the relationship between body fat composition and outcomes of patients with liver surgery from the start of each database to 29 October 2023. The Newcastle-Ottawa Scale was used to rate the quality of the studies.

RESULTS

This analysis included a total of 29 articles with a combined patient cohort of 6435 individuals. The results demonstrated that patients with high intramuscular fat content (IMFC) had significantly inferior overall survival (OS) [hazard ratio (HR): 2.07, 95% CI: 1.69-2.53, P <0.001] and recurrence-free survival (RFS) (HR: 1.61, 95% CI: 1.20-2.16, P =0.002) and a higher risk of major complications (HR: 2.20, 95% CI: 1.59-3.05, P <0.001). We also found that the presence of high visceral-to-subcutaneous fat tissue ratio (VSR) in patients with liver surgery was significantly related to poorer OS (HR: 1.70, 95% CI: 1.44-2.00, P <0.001) and progression-free survival (PFS) (HR: 1.29, 95% CI: 1.11-1.50, P =0.001) and a higher major complication rate (HR: 2.31, 95% CI: 1.17-4.56, P =0.016). Besides, the synthesized findings indicated there is no significant correlation between visceral fat tissue and survival outcomes or postoperative complications.

CONCLUSION

In summary, preoperative IMFC and VSR have the potential to forecast poorer OS and RFS and a higher risk of complications for patients undergoing hepatectomy or liver transplantation.

Shining a spotlight on sarcopenia and myosteatosis in liver disease and liver transplantation: Potentially modifiable risk factors with major clinical impact

Muscle-wasting and disease-related malnutrition are highly prevalent in patients with chronic liver diseases (CLD) as well as in liver transplant (LT) candidates. Alterations of body composition (BC) such as sarcopenia, myosteatosis and sarcopenic obesity and associated clinical frailty were tied to inferior clinical outcomes including hospital admissions, length of stay, complications, mortality and healthcare costs in various patient cohorts and clinical scenarios. In contrast to other inherent detrimental individual characteristics often observed in these complex patients, such as comorbidities or genetic risk, alterations of the skeletal muscle and malnutrition are considered as potentially modifiable risk factors with a major clinical impact. Even so, there is only limited high-level evidence to show how these pathologies should be addressed in the clinical setting. This review discusses the current state-of-the-art on the role of BC assessment in clinical outcomes in the setting of CLD and LT focusing mainly on sarcopenia and myosteatosis. We focus on the disease-related pathophysiology of BC alterations. Based on these, we address potential therapeutic interventions including nutritional regimens, physical activity, hormone and targeted therapies. In addition to summarizing existing knowledge, this review highlights novel trends, and future perspectives and identifies persisting challenges in addressing BC pathologies in a holistic way, aiming to improve outcomes and quality of life of patients with CLD awaiting or undergoing LT.

Association of myosteatosis with short-term outcomes in patients with acute-on-chronic liver failure

Sarcopenia (low muscle mass, i.e., quantity) is associated with poor clinical outcomes in patients with acute-on-chronic liver failure (ACLF). In this study, we aimed to illustrate the clinical prognostic value of myosteatosis (muscle fat infiltration) for short-term mortality in patients with ACLF. We retrospectively enrolled consecutive patients with ACLF between January 2019 and January 2022. Computed tomography-based body composition analysis was performed at the third lumbar vertebral level to determine skeletal muscle radiation attenuation. Fine and Gray's competing risk regression model, with liver transplantation as a competing risk, was used to assess the factors associated with 90-day mortality. A total of 431 patients with ACLF were included. Myosteatosis and sarcopenia were observed in 261 (60.6%) and 87 (20.2%) patients, respectively. Competitive risk regression showed that age (HR 1.021, 95% CI 1.000-1.043, P = 0.042), APASL ACLF Research Consortium (AARC) score (HR 1.498, 95% CI 1.312-1.710, P < 0.001), and sarcopenia (HR 1.802, 95% CI 1.062-3.060, P = 0.029) were independently associated with increased 90-day mortality. Subgroup analysis of male patients with HBV-ACLF revealed that myosteatosis (HR 2.119, 95% CI 1.101-4.078, P = 0.025) was promising prognostic factors for 90-day mortality after being adjusted for ascites, acute kidney injury, AARC score, and sarcopenia. Myosteatosis is predictive of short-term outcomes in male patients with HBV-ACLF. Our results emphasise the importance of focusing on muscle fat infiltration in patients with HBV-ACLF. Further studies are warranted to investigate the underlying mechanisms and potential therapies for myosteatosis.

Evolving concepts on perioperative nutrition of sarcopenic cancer patients

The recent recognition of the association of sarcopenia with an increased risk of complications after a surgical procedure calls for rethinking the proper approach of the perioperative care in cancer patients. Sarcopenia is broadly considered in literature according to three different definitions: loss of muscle mass, loss of muscle mass plus reduced muscle function and myosteatosis. The aim of this short review on this issue is to define the excess of risk by type of primary and of surgical procedure, depending on the definition of sarcopenia, to speculate on this association (casual versus causal) and to examine the current therapeutical approaches. The analysis of the data shows that sarcopenia, defined as loss of muscle mass plus reduced muscle function, has the higher predictive power for the occurrence of postoperative complications than the two other definitions, and any definition of sarcopenia works better than the usual indexes or scores of surgical risk. Our analysis supports the concept that: a) sarcopenia is frequently associated with inflammation, but inflammation cannot be considered the only or the absolute cause for sarcopenia, b) sarcopenia is not a simple marker of risk but can have a direct role in the increase of risk. Data on perioperative care of sarcopenic cancer patients are scanty but a correct approach cannot rely on nutritional support alone but on a combined approach of optimized nutrition and exercise, hopefully associated with an anti-inflammatory treatment. This strategy should be applied proactively in keeping with the recent recommendations of the American Society of Clinical Oncology for the medical treatment of advanced cancer patients even if a clear demonstration of effectiveness is still lacking.

Prevalence and impact on the outcome of myosteatosis in patients with cirrhosis: a systematic review and meta-analysis

BACKGROUND

Myosteatosis in cirrhotic patients has been evaluated in limited studies with conflicting results and no systematic review or meta-analysis have been performed in this setting.

METHODS

We searched for all articles published until June 2023 to evaluate the prevalence of myosteatosis in cirrhosis and chronic liver disease.

RESULTS

Seventeen studies focused on cirrhosis and five studies in patients with chronic liver disease were included: the overall pooled prevalence of myosteatosis was 46% [95% Confidence Interval (CI) 36-57%] and 33% (95% CI 15-59%), respectively (p = 0.35). Among the studies with cirrhosis, the prevalence of myosteatosis was higher in those using the body mass index-based definition of myosteatosis (56%), than gender-based (36%) or other criteria (21%) (p < 0.01); was higher in women than in men (61% vs 45%), in Child-Pugh class C than A or B (57% vs 49% vs 50%), in non-alcoholic fatty liver disease (NAFLD)- than viral-associated cirrhosis (57% vs 43%), but these differences were not statistically significant (p > 0.05). Cirrhotic patients with myosteatosis, compared to those without myosteatosis, had more frequently a previous history of hepatic encephalopathy (32% vs 15%, p = 0.04), less frequently a previous history of variceal bleeding (46% vs 65%, p < 0.01), were more likely to suffer from diabetes mellitus (27% vs 18%, p < 0.01), while they had higher mortality rates (40% vs 14%, p = 0.02).

CONCLUSION

Myosteatosis is highly prevalent in patients with cirrhosis, particularly in those with NAFLD-associated cirrhosis. Myosteatosis is associated with hepatic encephalopathy, while it seems to have a negative impact on the outcome.

Myosteatosis: Diagnosis, pathophysiology and consequences in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is associated with an increased risk of multisystemic complications, including muscle changes such as sarcopenia and myosteatosis that can reciprocally affect liver function. We conducted a systematic review to highlight innovative assessment tools, pathophysiological mechanisms and metabolic consequences related to myosteatosis in MASLD, based on original articles screened from PUBMED, EMBASE and COCHRANE databases. Forty-six original manuscripts (14 pre-clinical and 32 clinical studies) were included. Microscopy (8/14) and tissue lipid extraction (8/14) are the two main assessment techniques used to measure muscle lipid content in pre-clinical studies. In clinical studies, imaging is the most used assessment tool and included CT (14/32), MRI (12/32) and ultrasound (4/32). Assessed muscles varied across studies but mainly included paravertebral (4/14 in pre-clinical; 13/32 in clinical studies) and lower limb muscles (10/14 in preclinical; 13/32 in clinical studies). Myosteatosis is already highly prevalent in non-cirrhotic stages of MASLD and correlates with disease activity when using muscle density assessed by CT. Numerous pathophysiological mechanisms were found and included: high-fat and high-fructose diet, dysregulation in fatty acid transport and ketogenesis, endocrine disorders and impaired microRNA122 pathway signalling. In this review we also uncover several potential consequences of myosteatosis in MASLD, such as insulin resistance, MASLD progression from steatosis to metabolic steatohepatitis and loss of muscle strength. In conclusion, data on myosteatosis in MASLD are already available. Screening for myosteatosis could be highly relevant in the context of MASLD, considering its correlation with MASLD activity as well as its related consequences.

Liver transplantation in the patient with physical frailty

Frailty is a decline in functional reserve across multiple physiological systems. A key component of frailty is sarcopenia, which denotes a loss of skeletal muscle mass and impaired contractile function that ultimately result in physical frailty. Physical frailty/sarcopenia are frequent and contribute to adverse clinical outcomes before and after liver transplantation. Frailty indices, including the liver frailty index, focus on contractile dysfunction (physical frailty), while cross-sectional image analysis of muscle area is the most accepted and reproducible measure to define sarcopenia. Thus, physical frailty and sarcopenia are interrelated. The prevalence of physical frailty/sarcopenia is high in liver transplant candidates and these conditions have been shown to adversely impact clinical outcomes including mortality, hospitalisations, infections, and cost of care both before and after transplantation. Data on the prevalence of frailty/sarcopenia and their sex- and age-dependent impact on outcomes are not consistent in patients on the liver transplant waitlist. Physical frailty and sarcopenic obesity are frequent in the obese patient with cirrhosis, and adversely affect outcomes after liver transplantation. Nutritional interventions and physical activity remain the mainstay of management before and after transplantation, despite limited data from large scale trials. In addition to physical frailty, there is recognition that a global evaluation including a multidisciplinary approach to other components of frailty (e.g., cognition, emotional, psychosocial) also need to be addressed in patients on the transplant waitlist. Recent advances in our understanding of the underlying mechanisms of sarcopenia and contractile dysfunction have helped identify novel therapeutic targets.

The Presence of Myosteatosis Is Associated with Age, Severity of Liver Disease and Poor Outcome and May Represent a Prodromal Phase of Sarcopenia in Patients with Liver Cirrhosis

BACKGROUND/AIMS

Myosteatosis implies impaired muscle quality. The aim of the study was to investigate the association of myosteatosis with other muscle abnormalities and its role in the prognosis of liver cirrhosis (LC).

METHOD

Skeletal muscle index (SMI) and myosteatosis were measured by computed tomography. Myosteatosis was defined as muscle radiodensity and evaluated according to dry body mass index (BMI). Median values and interquartile range were used for continuous and count (percentage) for categorical variables.

RESULTS

A total of 197 consecutive patients were included (age 61 (IQR 52-68); 67% male; MELD score 11 (interquartile range 7.5-16)). Myosteatosis was identified in 73.6% and sarcopenia in 44.6% of patients. Myosteatosis was positively associated with age (p = 0.024) and Child-Pugh (p = 0.017) and inversely associated with SMI (p = 0.026). Patients with myosteatosis exhibited lower 360-day survival (log-rank p = 0.001) compared to those without it. MELD (p < 0.001) and myosteatosis (p = 0.048) emerged as negative prognostic factors of survival in multivariate model. Individuals combining low muscle strength and impaired muscle quality and quantity displayed more advanced LC, impaired muscle performance, lower BMI (p < 0.001 each) and a three times higher mortality rate compared to those with low muscle quality alone.

CONCLUSIONS

The presence of myosteatosis was associated with advanced age, low skeletal mass and more severe LC. Myosteatosis was associated with poor prognosis and may represent a prodromal phase of muscle degeneration before the development of sarcopenia.

Osteopenia is associated with inferior survival in patients undergoing partial hepatectomy for hepatocellular carcinoma

Osteopenia is known to be associated with clinical frailty which is linked to inferior outcomes in various clinical scenarios. However, the exact prognostic value of osteopenia in patients undergoing curative intent-surgery for hepatocellular carcinoma (HCC) is not completely understood. This retrospective study was conducted in a cohort of 151 patients who underwent partial hepatectomy for HCC in curative intent at a German university medical center (05/2008-12/2019). Preoperative computed tomography-based segmentation was used to assess osteopenia, and the prognostic impact of pathological changes in bone mineral density (BMD) on perioperative morbidity, mortality, and long-term oncological outcome was analyzed. Five-year overall survival of osteopenic patients was significantly worse compared to those with normal BMD (29% vs. 65%, p = 0.014). In line with this, the probability of disease-free survival at 5 years was significantly worse for patients with osteopenia (21% vs. 64%, p = 0.005). In our multivariable model, osteopenia was confirmed as an independent risk-factor for inferior overall survival (Hazard-ratio 7.743, p = 0.002). Concerning perioperative complications, osteopenic patients performed slightly worse, even though no statistical difference was detected (Clavien-Dindo ≥ 3b; 21% vs. 9%, p = 0.139). The present study confirms osteopenia as an independent risk-factor for inferior survival in patients undergoing partial hepatectomy for HCC in a European cohort. Further studies are warranted to validate these findings.

Body composition and the skeletal muscle compartment in liver transplantation: Turning challenges into opportunities

Frailty, nutritional status, and body composition are increasingly under the spotlight of interest in various clinical scenarios including liver transplantation. To address the rapidly accumulating evidence in this field, recent European and North American practice guidelines have clearly underlined the clinical importance of nutritional status and body composition with adopting their assessment in patients with liver disease and in transplant candidates into their recommendations. While earlier reports, and therefore present guidelines, were focusing predominantly on quantitative alterations of the skeletal muscle mass (sarcopenia), recent studies have identified qualitative alterations such as intramuscular fat accumulation (myosteatosis) and sarcopenic obesity as emerging risk factors for poor clinical outcomes. In this review, the role of body composition in the context of liver transplantation will be discussed with a focus on the skeletal muscle compartment. A brief overview of current assessment modalities including their limitations, diagnostic challenges, prognostic significance, and pathophysiology are included. Possibilities to incorporate body composition parameters into clinical decision making are discussed. In addition, novel trends and remaining challenges in the therapeutic targeting of body composition and the skeletal muscle compartment are highlighted.

Body fat composition determines outcomes before and after liver transplantation in patients with cirrhosis

Cachexia occurs in late stages of liver cirrhosis, and a low-fat mass is potentially associated with poor outcome. This study compared different computed tomography (CT)-derived fat parameters with respect to its prognostic impact on the development of complications and death before and after liver transplantation. Between 2001 and 2014, 612 patients with liver cirrhosis without hepatocellular carcinoma listed for liver transplantation met the inclusion criteria, including abdominal CT scan (±200 days to listing). A total of 109 patients without cirrhosis served as controls. The subcutaneous fat index (SCFI), the paraspinal muscle fat index, and the visceral fat index were assessed at L3/L4 level and normalized to the height (cm² /m² ). Data were collected and analyzed retrospectively. Low SCFI was associated with a higher rate of ascites and increased C-reactive protein levels (p < 0.001). In addition, multivariate Cox regression analysis adjusting for sex, age, body mass index (BMI), and Model for End-Stage Liver Disease showed that decreasing SCFI was also associated with an increased risk of cirrhosis-related complications (p = 0.003) and death on the transplant wait list (p = 0.013). Increased paraspinal and visceral fat were not only positively correlated with creatinine levels (p < 0.001), BMI, and metabolic comorbidities (all p < 0.001) before transplantation, but also predictive for 1-year mortality after transplantation. Conclusion: The distribution of body fat is a major determinant for complications and outcome in cirrhosis before and after liver transplantation.

Skeletal Muscle Pathological Fat Infiltration (Myosteatosis) Is Associated with Higher Mortality in Patients with Cirrhosis

Myosteatosis (pathological fat accumulation in muscle) is defined by lower mean skeletal muscle radiodensity in CT. We aimed to determine the optimal cut-offs for myosteatosis in a cohort of 855 patients with cirrhosis. CT images were used to determine the skeletal muscle radiodensity expressed as Hounsfield Unit (HU). Patients with muscle radiodensity values below the lowest tertile were considered to have myosteatosis. Competing-risk analysis was performed to determine associations between muscle radiodensity and pre-transplant mortality. Muscle radiodensity less than 33 and 28 HU in males and females, respectively, were used as cut-offs to identify myosteatosis. In the univariate analysis, cirrhosis etiology, MELD score, refractory ascites, variceal bleeding, hepatic encephalopathy, sarcopenia and myosteatosis were predictors of mortality. Myosteatosis association with mortality remained significant after adjusting for confounding factors (sHR 1.47, 95% CI 1.17−1.84, p = 0.001). Patients with concurrent presence of myosteatosis and sarcopenia constituted 17% of the patient population. The cumulative incidence of mortality was the highest in patients with concomitant sarcopenia and myosteatosis (sHR 2.22, 95% CI 1.64−3.00, p < 0.001). In conclusion, myosteatosis is common in patients with cirrhosis and is associated with increased mortality. The concomitant presence of myosteatosis and sarcopenia is associated with worse outcomes.

Myosteatosis in Cirrhosis: A Review of Diagnosis, Pathophysiological Mechanisms and Potential Interventions

Myosteatosis, or pathological excess fat accumulation in muscle, has been widely defined as a lower mean skeletal muscle radiodensity on computed tomography (CT). It is reported in more than half of patients with cirrhosis, and preliminary studies have shown a possible association with reduced survival and increased risk of portal hypertension complications. Despite the clinical implications in cirrhosis, a standardized definition for myosteatosis has not yet been established. Currently, little data exist on the mechanisms by which excess lipid accumulates within the muscle in individuals with cirrhosis. Hyperammonemia may play an important role in the pathophysiology of myosteatosis in this setting. Insulin resistance, impaired mitochondrial oxidative phosphorylation, diminished lipid oxidation in muscle and age-related differentiation of muscle stem cells into adipocytes have been also been suggested as potential mechanisms contributing to myosteatosis. The metabolic consequence of ammonia-lowering treatments and omega-3 polyunsaturated fatty acids in reversing myosteatosis in cirrhosis remains uncertain. Factors including the population of interest, design and sample size, single/combined treatment, dosing and duration of treatment are important considerations for future trials aiming to prevent or treat myosteatosis in individuals with cirrhosis.

The Role of Sarcopenia and Myosteatosis in Short- and Long-Term Outcomes Following Curative-Intent Surgery for Hepatocellular Carcinoma in a European Cohort

Simple Summary

Recent studies have shown that pathological changes of body composition, in particular reduced muscle mass (sarcopenia) and impaired muscle quality (myosteatosis), are linked to poor outcomes in a variety of clinical conditions. Hepatocellular carcinoma (HCC) is the most frequent primary malignant tumor of the liver in the Western hemisphere and remains a prominent cause of cancer-associated mortality. The present study investigates the prognostic value of alterations in body composition in predicting perioperative morbidity, mortality and long-term oncological outcome in HCC using preoperative computed-tomography-based segmentation. Our study found supporting evidence for the relevance of muscle quality over quantity in a European population and verifies the predictive role of myosteatosis in patients suffering from HCC, with a particularly significant value in the earlier perioperative phase.

Abstract

Alterations of body composition, especially decreased muscle mass (sarcopenia) and impaired muscle quality (myosteatosis), are associated with inferior outcomes in various clinical conditions. The data of 100 consecutive patients who underwent partial hepatectomy for hepatocellular carcinoma (HCC) at a German university medical centre were retrospectively analysed (May 2008–December 2019). Myosteatosis and sarcopenia were evaluated using preoperative computed-tomography-based segmentation. We investigated the predictive role of alterations in body composition on perioperative morbidity, mortality and long-term oncological outcome. Myosteatotic patients were significantly inferior in terms of major postoperative complications (Clavien–Dindo ≥ 3b; 25% vs. 5%, p = 0.007), and myosteatosis could be confirmed as an independent risk factor for perioperative morbidity in multivariate analysis (odds ratio: 6.184, confidence interval: 1.184–32.305, p = 0.031). Both sarcopenic and myosteatotic patients received more intraoperative blood transfusions (1.6 ± 22 vs. 0.3 ± 1 units, p = 0.000; 1.4 ± 2.1 vs. 0.3 ± 0.8 units, respectively, p = 0.002). In terms of long-term overall and recurrence-free survival, no statistically significant differences could be found between the groups, although survival was tendentially worse in patients with reduced muscle density (median survival: 41 vs. 60 months, p = 0.223). This study confirms the prognostic role of myosteatosis in patients suffering from HCC with a particularly strong value in the perioperative phase and supports the role of muscle quality over quantity in this setting. Further studies are warranted to validate these findings.