Psoas Muscle Index Does Not Predict Post-Transplant Outcomes: A Series of 57 Liver Transplant Recipients

Sarcopenia As a Predictor of Survival and Complications of Patients With Cirrhosis After Liver Transplantation: A Systematic Review and Meta-Analysis

INTRODUCTION

This systematic review/meta-analysis evaluated the impact of sarcopenia in patients with cirrhosis before liver transplantation (LT) on outcomes after LT.

METHODS

A systematic search was conducted in six medical databases until February 2022. The primary outcome was overall mortality after LT, while several secondary outcomes including liver graft survival and rejection, the need for transfusions, the length of the intensive care unit (ICU) and hospital stay, and surgical complications were evaluated. Sub-group analyses and meta-regression analyses were also performed.

RESULTS

Fifty-three studies were evaluated in the systematic review, of which 30, including 5875 patients, were included in the meta-analysis. All studies included were cohort studies of good/high quality on the Newcastle-Ottawa scale (NOS), while in our analysis no publication bias was found, although there was substantial heterogeneity between the studies. Muscle mass was assessed using skeletal muscle index (SMI) in 14 studies, psoas muscle area (PMA) in seven studies, and psoas muscle index (PMI) in four studies. The prevalence of pre-LT sarcopenia ranged from 14.7% to 88.3%. Pre-LT sarcopenia was significantly associated with post-LT mortality (Relative Risk [RR] = 1.84, 95% CI:1.41,2.39), as well as with a high risk of infections post-LT, surgical complications, fresh frozen plasma (FFP) transfusions, and ICU length of stay (LOS).

CONCLUSIONS

Pre-LT sarcopenia in patients with cirrhosis is a strong risk factor for clinically meaningful adverse outcomes after LT. Assessment may help identify patients at the highest risk for poor outcomes who may benefit from targeted interventions.

CT-derived psoas muscle area and density are associated with length of stay and discharge disposition after liver transplantation

BACKGROUND & AIMS

Prolonged length of stay (LOS) and discharge disposition following liver transplantation are associated with postoperative complications and increased healthcare utilization. This study evaluated the relationship between CT-derived psoas muscle measurements and hospital LOS, intensive care unit (ICU) LOS, and discharge disposition after liver transplant. The psoas muscle was chosen given its ease of measurement with any radiological software. A secondary analysis assessed the relationship between the American Society for Parenteral and Enteral Nutrition and the Academy of Nutrition and Dietetics (ASPEN/AND) malnutrition diagnosis criteria and CT-derived psoas muscle measures.

METHODS

CT-derived measures of psoas muscle density (mHU) and cross-sectional area at the level of the third lumbar vertebrae were obtained from preoperative CT scans of liver transplant recipients. Cross-sectional area measures were corrected for body size to generate a psoas area index variable (cm²/m²; PAI).

RESULTS

Each 1-unit increase in PAI was associated with a reduced hospital LOS of 4 days (R² = 0.07). Each 5-unit increase in mean Hounsfield units (mHU) was associated with a reduced hospital and ICU LOS of 5 and 1.6 days, respectively (R² = 0.22 and 0.14, respectively). Mean PAI and mHU were higher in patients who discharged to home. PAI was reasonably identified through ASPEN/AND malnutrition criteria, but there was no difference in mHU between those with and without malnutrition.

CONCLUSION

Measures of psoas density were associated with both hospital and ICU LOS and discharge disposition. PAI was associated with hospital LOS and discharge disposition. CT-derived measures of psoas density may be a valuable complement to preoperative liver transplant nutrition assessment using traditional ASPEN/AND malnutrition criteria.

Psoas muscle index predicts time to rehospitalization in liver cirrhosis: An observational study

Sarcopenia is frequent in liver cirrhosis (LC) where it is associated with morbidity and mortality. However, prognostic scores such as model for end-stage liver disease (MELD), MELD-sodium (MELD-Na), or Child-Turcotte-Pugh (CTP) do not contain sarcopenia as a variable. For this study, we utilized psoas muscle index (PMI) to objectively determine sarcopenia in hospitalized LC patients, and evaluated it as a predictor of time between discharge and readmission in LC. Abdominal computed tomography and magnetic resonance imaging scans of 65 consecutive LC patients were retrospectively examined to determine PMI. MELD, MELD-Na, and CTP were calculated from clinical data. PMI was then combined with CTP to form an experimental score: CTP sarcopenia (CTPS). For PMI alone and for each score, correlation with time between discharge and readmission for liver-related complications was calculated. PMI was also tested for correlation with sex, body mass index (BMI), MELD, MELD-Na, and CTP. CTPS was most closely correlated with time to readmission (R = 0.730; P < .001), followed by CTP (R = 0.696; P < .001), MELD-Na (R = 0.405; P = .009), and PMI alone (R = 0.388; P = .01). Correlation with MELD (R = 0.354; P = .05) was lowest. Additionally, there were significant differences in PMI between male and female individuals (5.16 vs 4.54 cm2/m2; P = .04) and in BMI between sarcopenic and nonsarcopenic individuals (29.63 vs 25.88 kg/m2; P = .009). Sarcopenia is an independent short-term prognostic factor in LC. By combining data on sarcopenia with CTP, we created an experimental score that predicts time to readmission better than MELD, MELD-Na, or CTP.

Implications of pre-transplant sarcopenia and frailty in patients with non-alcoholic steatohepatitis and alcoholic liver disease

Frailty manifesting as sarcopenia is an independent risk factor for mortality in cirrhosis, and often presents in low model for end-stage liver disease (MELD) patients. Its etiology is multifactorial, but key physiologic changes culminate in altered energy utilization in the fasting state, preferentially utilizing muscle amino acids for gluconeogenesis thereby promoting sarcopenia. Hyperammonemia alters the circulating amino acid profile, diminishing pro-muscle branched-chain amino acids like leucine. The metabolic syndrome worsens sarcopenia through multi-tissue insulin resistance. Alcohol also exacerbates sarcopenia as a direct muscle toxin and inhibitor of growth signaling. Therapy is aimed at alcohol cessation, frequent high-protein meals, branched-chain amino acid supplementation, and diminished time spent fasting. Moderate exercise can improve muscle mass and muscle quality, though precise exercise regimens have not yet been explicitly determined. Studies are ongoing into the effects of myostatin antagonists and insulin sensitizers. The Liver Frailty Index can predict patients most at risk of poor outcome and should be considered in the management of all cirrhotic patients. Specialty testing like dual-energy X-ray absorptiometry (DEXA) scanning and cross-sectional estimates of muscle mass are areas of active research and may play a future role in clinical risk-stratification.