Aerobic capacity during cardiopulmonary exercise testing and survival with and without liver transplantation for patients with chronic liver disease

Frailty in liver transplantation: Exploring prescribing exercise as medicine to improve patient outcomes

Liver transplantation (LT) represents a curative avenue for individuals with advanced chronic liver disease. Given the inherent illness severity of LT candidates, identifying patients at greater risk for adverse outcomes before and after transplantation is paramount. Approximately 50% of cirrhotic patients are frail and have considerable functional impairment. Various measures have been used to assess frailty, including performance-based tests and functional status evaluations. Frailty carries significant prognostic implications and predicts both mortality and pre- and post-LT complications. Contributing factors to frailty in this population include sarcopenia, malnutrition, inflammation, and psychosocial factors. Recognizing the prevalence of frailty among LT candidates, exercise interventions have been developed to improve physical frailty and offer potential to improve patient outcomes. While many interventions have demonstrated efficacy without notable adverse events, the absence of a universally accepted standard for exercise prescription underscores the variability in intervention elements and patient adherence. Given the safety profile of exercise interventions, there remains a critical need for standardized protocols and guidelines to optimize exercise regimens for LT candidates. This review delves into the landscape of frailty among LT candidates, elucidating its etiological underpinnings, impact on outcomes, utilization of exercise interventions, and the efficacy of exercise programs in reducing the burden frailty in those awaiting LT.

Duke Activity Status Index and Liver Frailty Index predict mortality in ambulatory patients with advanced chronic liver disease: A prospective, observational study

BACKGROUND

There remains a lack of consensus on how to assess functional exercise capacity and physical frailty in patients with advanced chronic liver disease (CLD) being assessed for liver transplantation (LT). Aim To investigate prospectively the utility of the Duke Activity Status Index (DASI) and Liver Frailty Index (LFI) in ambulatory patients with CLD.

AIM

To investigate prospectively the utility of the Duke Activity Status Index (DASI) and Liver Frailty Index (LFI) in ambulatory patients with CLD.

METHODS

We recruited patients from outpatient clinics at University Hospitals Birmingham, UK (2018-2019). We prospectively collated the DASI and LFI to identify the prevalence of, respectively, functional capacity and physical frailty, and to evaluate their accuracy in predicting overall and pre-LT mortality.

RESULTS

We studied 307 patients (57% male; median age 54 years; UKELD 52). Median DASI score was 28.7 (IQR 16.2-50.2), mean LFI was 3.82 (SD = 0.72), and 81% were defined either 'pre-frail' or 'frail'. Female sex and hyponatraemia were significant independent predictors of both DASI and LFI. Age and encephalopathy were significant independent predictors of LFI, while BMI significantly predicted DASI. DASI and LFI were significantly related to overall (HR 0.97, p = 0.001 [DASI], HR 2.04, p = 0.001 [LFI]) and pre-LT mortality (HR 0.96, p = 0.02 [DASI], HR 1.94, p = 0.04 [LFI]).

CONCLUSIONS

Poor functional exercise capacity and physical frailty are highly prevalent among ambulatory patients with CLD who are being assessed for LT. The DASI and LFI are simple, low-cost tools that predict overall and pre-LT mortality. Implementation of both should be considered in all outpatients with CLD to highlight those who may benefit from targeted nutritional and exercise interventions.

Prediction of peak oxygen consumption using cardiorespiratory parameters from warmup and submaximal stage of treadmill cardiopulmonary exercise test

This study investigates the quality of peak oxygen consumption (VO2peak) prediction based on cardiac and respiratory parameters calculated from warmup and submaximal stages of treadmill cardiopulmonary exercise test (CPET) using machine learning (ML) techniques and assesses the importance of respiratory parameters for the prediction outcome. The database consists of the following parameters: heart rate (HR), respiratory rate (RespRate), pulmonary ventilation (VE), oxygen consumption (VO2) and carbon dioxide production (VCO2) obtained from 369 treadmill CPETs. Combinations of features calculated based on the HR, VE and RespRate time-series from different stages of CPET were used to create 11 datasets for VO2peak prediction. Thirteen ML algorithms were employed, and model performances were evaluated using cross-validation with mean absolute percentage error (MAPE), R2 score, mean absolute error (MAE), and root mean squared error (RMSE) calculated after each iteration of the validation. The results demonstrated that incorporating respiratory-based features improves the prediction of VO2peak. The best results in terms of R2 score (0.47) and RMSE (5.78) were obtained for the dataset which included both cardiac- and respiratory-based features from CPET up to 85% of age-predicted HRmax, while the best results in terms of MAPE (10.5%) and MAE (4.63) were obtained for the dataset containing cardiorespiratory features from the last 30 seconds of warmup. The study showed the potential of using ML models based on cardiorespiratory features from submaximal tests for prediction of VO2peak and highlights the importance of the monitoring of respiratory signals, enabling to include respiratory parameters into the analysis. Presented approach offers a feasible alternative to direct VO2peak measurement, especially when specialized equipment is limited or unavailable.

Liver Transplantation and the Elderly Candidate: Perioperative Considerations

Pioneered by Thomas Starzl in the early 1970s, liver transplant (LT) is nowadays often considered a final intervention and standard of care to cure many forms of acute and chronic end-stage liver diseases. Started in recipients younger than 60 years old, LT indications are now much broader, and at least, one-fifth of the candidates are older than 65 years. Problems associated with ageing and frailty in LT recipients and their impact on the entire perioperative course are discussed according to a modern anesthesiological perspective and the anesthesiologist covering the role of the perioperative (transplant) physician.

Exercise interventions for adults after liver transplantation

BACKGROUND

The finding that exercise is inversely related to metabolic syndrome after transplantation is novel and suggests that exercise interventions might provide a means for reducing metabolic syndrome complications in liver transplantation recipients. The use of exercise for increasing the physical activity daily levels by more frequent, higher intensity, and longer duration of training sessions, or the sum of these components may be necessary to counteract the effects of the pretransplant reduced activity, metabolic disturbances, and post-transplant immunosuppression, as well as improve physical function and aerobic capacity following liver transplantation. Regular physical activity has a long-term positive impact on recovery following various surgical procedures including transplantation, giving people the opportunity to return to an active life with their families, in society, and in their professional life. Likewise, specific muscle strength training may attenuate the loss of strength after liver transplantation.

OBJECTIVES

To evaluate the benefits and harms of exercise-based interventions in adults after liver transplantation compared to no exercise, sham interventions, or another type of exercise.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 2 September 2022.

SELECTION CRITERIA

We included randomised clinical trials in liver transplantation recipients comparing any type of exercise with no exercise, sham interventions, or another type of exercise.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. all-cause mortality; 2. serious adverse events; and 3. health-related quality of life. Our secondary outcomes were 4. a composite of cardiovascular mortality and cardiac disease; 5. aerobic capacity; 6. muscle strength; 7. morbidity; 8. non-serious adverse events; and 9. cardiovascular disease post-transplantation. We assessed risk of bias of the individual trials using RoB 1, described the interventions using the TIDieR checklist, and used GRADE to assess certainty of evidence.

MAIN RESULTS

We included three randomised clinical trials. The trials randomised 241 adults with liver transplantation, of which 199 participants completed the trials. The trials were conducted in the USA, Spain, and Turkey. They compared exercise versus usual care. The duration of the interventions ranged from two to 10 months. One trial reported that 69% of participants who received the exercise intervention were adherent to the exercise prescription. A second trial reported a 94% adherence to the exercise programme, with participants attending 45/48 sessions. The remaining trial reported a 96.8% adherence to the exercise intervention during the hospitalisation period. Two trials received funding; one from the National Center for Research Resources (US) and the other from Instituto de Salud Carlos III (Spain). The remaining trial did not receive funding. All trials were at an overall high risk of bias, derived from high risk of selective reporting bias and attrition bias in two trials. The results on all-cause mortality showed a higher risk of death in the exercise group versus the control group, but these results are very uncertain (risk ratio (RR) 3.14, 95% confidence interval (CI) 0.74 to 13.37; 2 trials, 165 participants; I² = 0%; very low-certainty evidence). The trials did not report data on serious adverse events excluding mortality or non-serious adverse events. However, all trials reported that there were no adverse effects associated with exercise. We are very uncertain on whether exercise compared with usual care has a beneficial or harmful effect on health-related quality of life assessed using the 36-item Short Form Physical Functioning subscale at the end of the intervention (mean difference (MD) 10.56, 95% CI -0.12 to 21.24; 2 trials, 169 participants; I² = 71%; very low-certainty evidence). None of the trials reported data on composite of cardiovascular mortality and cardiovascular disease, and cardiovascular disease post-transplantation. We are very uncertain if there are differences in aerobic capacity in terms of VO2peak at the end of the intervention between groups (MD 0.80, 95% CI -0.80 to 2.39; 3 trials, 199 participants; I² = 0%; very low-certainty evidence). We are very uncertain if there are differences in muscle strength at end of the intervention between groups (MD 9.91, 95% CI -3.68 to 23.50; 3 trials, 199 participants; I² = 44%; very low-certainty evidence). One trial measured perceived fatigue using the Checklist Individual Strength (CIST). Participants in the exercise group showed a clinically important lower degree of fatigue perception than participants in the control group, with a mean reduction of 40 points in the CIST (95% CI 15.62 to 64.38; 1 trial, 30 participants).  We identified three ongoing studies.

AUTHORS' CONCLUSIONS

Based on very low-certainty evidence in our systematic review, we are very uncertain of the role of exercise training (aerobic, resistance-based exercises, or both) in affecting mortality, health-related quality of life, and physical function (i.e. aerobic capacity and muscle strength) in liver transplant recipients. There were few data on the composite of cardiovascular mortality and cardiovascular disease, cardiovascular disease post-transplantation, and adverse event outcomes. We lack larger trials with blinded outcome assessment, designed according to the SPIRIT statement and reported according to the CONSORT statement.

Psoas Muscle Index: A Simple and Reliable Method of Sarcopenia Assessment on Computed Tomography Scan in Chronic Liver Disease and its Impact on Mortality

Objectives

Psoas muscle parameters have been proposed as a simple and quick method for sarcopenia assessment. The aim of this study was to assess sarcopenia in cirrhotics by psoas muscle on computed tomography and its impact on mortality.

Methods

One hundred and fifty patients (75 cirrhotics, 75 subjects) were assessed for psoas muscle on CT scan. Psoas muscle index (PMI) was calculated as 'total psoas muscle area/(height of subject)2'. Cut off values for sarcopenia diagnosis were derived from local subjects (n = 75) who did not have cirrhosis/other causes of sarcopenia.

Results

Sarcopenia assessed by PMI was seen in 36% (n = 27) of the cirrhotics. Sarcopenia was significantly higher in patients having Child-Pugh C. Ascites, hepatic encephalopathy (HE) and gastro-intestinal bleed were seen in 48%, 18.7% and 24%, respectively. Sarcopenia was significantly associated with ascites and HE (P < 0.05). Out of the 75 cases, 53 cases completed the follow-up period of 1 year. Among the 20 cases who had sarcopenia, 35% (n = 7) succumbed to liver-related illness during 1 year follow-up, and out of the 33 cases without sarcopenia, only 6% (n = 2) died. The association of sarcopenia and 1 year mortality was statistically significant (P = 0.01).

Conclusions

The PMI, a simple method for sarcopenia assessment detected sarcopenia in 36% of cirrhotics. Patients with sarcopenia had a significantly higher 1 year mortality rate and appropriate prognostication of such patients is needed.

Therapeutic Physical Exercise Programs in the Context of NASH Cirrhosis and Liver Transplantation: A Systematic Review

In recent years, various physical exercise interventions have been developed with a view to reducing comorbidity and morbidity rates among patients with chronic diseases. Regular physical exercise has been shown to reduce hypertension and mortality in patients with type 2 diabetes. Diabetes and obesity are often associated with the development of nonalcoholic fatty liver disease, which can lead to liver fibrosis and then (in some cases) nonalcoholic steatohepatitis cirrhosis. We searched the literature for publications on personalized physical exercise programs in cirrhotic patients before and after liver transplantation. Eleven studies in cirrhotic patients and one study in liver transplant recipients were included in the systematic review, the results of which were reported in compliance with the preferred reporting items for systematic reviews and meta-analyses guidelines. The personalized physical exercise programs lasted for 6 to 16 weeks. Our review evidenced improvements in peak oxygen consumption and six-minute walk test performance and a reduction in the hepatic venous pressure gradient. In cirrhotic patients, personalized physical exercise programs improve quality of life, are not associated with adverse effects, and (for transplant recipients) might reduce the 90-day hospital readmission rate. However, none of the literature data evidenced reductions in the mortality rates before and after transplantation. Further prospective studies are needed to evaluate the benefit of long-term physical exercise programs in cirrhotic patients before and after liver transplantation.

Effects of an active lifestyle on the physical frailty of liver transplant candidates

BACKGROUND

Liver transplantation is the most important therapeutic intervention for end-stage liver disease (ELD). The prioritization of these patients is based on the model for end-stage liver disease (MELD), which can successfully predict short-term mortality. However, despite its great validity and value, it cannot fully incorporate several comorbidities of liver disease, such as sarcopenia and physical frailty, variables that can sufficiently influence the survival of such patients. Subsequently, there is growing interest in the importance of physical frailty in regard to mortality in liver transplant candidates and recipients, as well as its role in improving their survival rates.

AIM

To evaluate the effects of an active lifestyle on physical frailty on liver transplant candidates.

METHODS

An observational study was performed within the facilities of the Department of Transplant Surgery of Aristotle University of Thessaloniki. Twenty liver transplant candidate patients from the waiting list of the department were included in the study. Patients that were bedridden, had recent cardiovascular incidents, or had required inpatient treatment for more than 5 d in the last 6 mo were excluded from the study. The following variables were evaluated: Activity level via the International Physical Activity Questionnaire (IPAQ); functional capacity via the 6-min walking test (6MWT) and cardiopulmonary exercise testing; and physical frailty via the Liver Frailty Index (LFI).

RESULTS

According to their responses in the IPAQ, patients were divided into the following two groups based on their activity level: Active group (A, 10 patients); and sedentary group (S, 10 patients). Comparing mean values of the recorded variables showed the following results: MELD (A: 12.05 ± 5.63 vs S: 13.99 ± 3.60; P > 0.05); peak oxygen uptake (A: 29.78 ± 6.07 mL/kg/min vs S: 18.11 ± 3.39 mL/kg/min; P < 0.001); anaerobic threshold (A: 16.71 ± 2.17 mL/kg/min vs S: 13.96 ± 1.45 mL/kg/min; P < 0.01); 6MWT (A: 458.2 ± 57.5 m vs S: 324.7 ± 55.8 m; P < 0.001); and LFI (A: 3.75 ± 0.31 vs S: 4.42 ± 0.32; P < 0.001).

CONCLUSION

An active lifestyle can be associated with better musculoskeletal and functional capacity, while simultaneously preventing the evolution of physical frailty in liver transplant candidates. This effect appears to be independent of the liver disease severity.

Association of physiological reserve measures with adverse outcomes following liver transplantation

Background and Aim

The comparative utility of physiological reserve measures in predicting important clinical outcomes following liver transplantation (LT) requires further study. The aim of this work was therefore to compare the utility of physiological reserve measures in predicting early adverse clinical outcomes post‐LT.

Methods

A single‐center, retrospective cohort study of LT patients consecutively recruited between 1 January 2015, and 31 August 2020. Outcomes measured were sepsis and death within 12 months of LT, hospital length of stay (LOS), and intensive care LOS. Physiological reserve measures were handgrip strength, mid‐arm muscle circumference, and cardiopulmonary exercise testing (CPET) measures. Analysis was performed using univariate and multivariate logistic regression for sepsis and death, and univariate and multivariate Cox regression for hospital and intensive care LOS.

Results

Data were obtained for 109 subjects. Patients were predominantly (64%) male with a median (interquartile range [IQR]) age of 57 (49–63) and median (IQR) Model for End‐Stage Liver Disease score of 16 (11–21). In multivariate analysis, the odds of sepsis were lower in patients in the highest versus lowest tertile (odds ratio = 0.004; 95% confidence interval [CI] 0.00–0.13; P = 0.002). Hospital LOS was linearly associated with handgrip strength (hazard ratio [HR] = 1.03; 95% CI 1.00–1.06; P = 0.03) in multivariate analysis. Intensive care LOS was associated with peak VO₂ (HR 1.83; 95% CI 1.06–3.16; P = 0.03) and V_E/VCO₂ slope (HR 0.71; 95% CI 0.58–0.88; P = 0.002) in multivariate analysis.

Conclusion

Handgrip strength and CPET both identify candidates at high risk of adverse outcomes after LT.

Physiological predictors of cardiorespiratory fitness in children and adolescents with cystic fibrosis without ventilatory limitation

Objectives:

[1] To investigate the cardiorespiratory fitness (CRF) levels in children and adolescents with cystic fibrosis (CF) with no ventilatory limitation (ventilatory reserve ⩾ 15%) during exercise, and [2] to assess which physiological factors are related to CRF.

Methods:

A cross-sectional study design was used in 8- to 18-year-old children and adolescents with CF. Cardiopulmonary exercise testing was used to determine peak oxygen uptake normalized to body weight as a measure of CRF. Patients were defined as having ‘low CRF’ when CRF was less than 82%predicted. Physiological predictors used in this study were body mass index z-score, P. Aeruginosa lung infection, impaired glucose tolerance (IGT) including CF-related diabetes, CF-related liver disease, sweat chloride concentration, and self-reported physical activity. Backward likelihood ratio (LR) logistic regression analysis was used.

Results:

Sixty children and adolescents (51.7% boys) with a median age of 15.3 years (25th–75th percentile: 12.9–17.0 years) and a mean percentage predicted forced expiratory volume in 1 second of 88.5% (±16.9) participated. Mean percentage predicted CRF (ppVO_2peak/kg) was 81.4% (±12.4, range: 51%–105%). Thirty-three patients (55.0%) were classified as having ‘low CRF’. The final model that best predicted low CRF included IGT (p = 0.085; Exp(B) = 6.770) and P. Aeruginosa lung infection (p = 0.095; Exp(B) = 3.945). This model was able to explain between 26.7% and 35.6% of variance.

Conclusions:

CRF is reduced in over half of children and adolescents with CF with normal ventilatory reserve. Glucose intolerance and P. Aeruginosa lung infection seem to be associated to low CRF in children and adolescents with CF.

Exercise physiology in cirrhosis and the potential benefits of exercise interventions: A review

Reduction in muscle mass is a highly prevalent phenomenon in cirrhosis and is now well-documented to be associated with significant morbidity and mortality. Research into muscle loss in cirrhosis remains limited by an ongoing poor understanding of its relationship with muscle function, physical activity, and aerobic capacity. Alterations in exercise physiology have been documented in studies of individuals with cirrhosis that provide important information on physical function that is not captured by simple quantification of muscle mass. Despite expert consensus recommending regular exercise in end-stage liver disease to maintain muscle mass and function, there is little evidence guiding clinicians as to which form of exercise or delivery mechanism is most effective. It also remains unproven whether any specific intervention can alter clinically relevant outcomes. This review article summarizes the available literature regarding the changes in exercise physiology observed in cirrhosis, the associated impact on physical capacity, and the results of existing trials that examine the potential benefits of exercise delivery in patients with cirrhosis, particularly pertaining to their impact on exercise physiology.

Sarcopenia-The Impact on Physical Capacity of Liver Transplant Patients

Optimizing patients' condition before liver transplantation (LT) could potentially improve survival of LT patients. We focused on sarcopenia, as a common factor in liver transplant candidates that can impact their cardiopulmonary performance at the point of listing, morbidity, and mortality after LT. We performed a single-center cohort study on 98 consecutive patients with liver cirrhosis who were transplanted between March 2015 and December 2017. The third lumbar vertebra skeletal muscle index (L3SMI) was calculated using CT imaging to distinguish sarcopenia at listing for LT. Data regarding liver function, body mass index (BMI), cardiac biomarkers, the peak oxygen uptake (VO2) and LT outcome were collected and correlated to L3SMI. For data analysis the Dell Statistica (Version 13. Dell Inc., Rondrock, TX, USA) was used. In total, 98 cirrhotic patients were included. Fifty-five (56.1%) patients, mostly males, had sarcopenia according to L3SMI, with the lowest L3SMI in males with alcohol-related liver disease. Lower L3SMI correlated with lower BMI, lower VO2 peak, and higher NTproBNP (all p < 0.001) and revealed an essential correlation with prolonged ICU stay (r = -0.21, p < 0.05). 33 patients were unable to perform cardio-pulmonary exercise test, mostly sarcopenic (67%), with more advanced liver insufficiency (assessed with CPC and MELD scores) and longer stay at ICU after LT (all p < 0.001). Sarcopenia was common among LT recipients. It was associated with inferior result in cardio-pulmonary performance before LT and prolonged ICU stay after grafting.

Physiologic Reserve Assessment and Application in Clinical and Research Settings in Liver Transplantation

Physiologic reserve is an important prognostic indicator. Because of its complexity, no single test can measure an individual's physiologic reserve. Frailty is the phenotypic expression of decreased reserve and portends poor prognosis. Both subjective and objective tools have been used to measure one or more components of physiologic reserve. Most of these tools appear to predict pretransplant mortality, but only some predict posttransplant survival. Incorporation of these measures of physiologic reserve in the clinical and research settings including prediction models are reviewed, and the applicability to patient-related outcomes are discussed. Commonly used tools, in patients with cirrhosis, that have been associated with clinical outcomes were reviewed. The strength of subjective tools lies in low-cost, wide availability, and quick assessments at the bedside. A disadvantage of these tools is the manipulative capacity, restricting their value in allocation processes. The strength of objective tests lies in objective measurements and the ability to measure change. The disadvantages include complexity, increased cost, and limited accessibility. Heterogeneity in the definitions and tools used has prevented further advancement or a clear role in transplant assessment. Consistent use of objective tools, including the 6-minute walk test, gait speed, Liver Frailty Index, or Short Physical Performance Battery, are recommended in clinical and research settings.

Assessment of the Frail Patient With End-Stage Liver Disease: A Practical Overview of Sarcopenia, Physical Function, and Disability

Frailty has emerged as a powerful predictor of clinical outcomes (e.g., decompensation, hospitalization, mortality) in patients with end-stage liver disease (ESLD). It is therefore of paramount importance that all patients with ESLD undergo an assessment of frailty, to support life and death decision making (i.e., candidacy for critical care, transplantation) and aid with prioritization of evolving prehabilitation services (i.e., nutrition, physiotherapy, psychotherapy). This article aims to provide a practical overview of the recent advances in the clinical, radiological, and remote assessment tools of the frail patient with ESLD. Historically, clinicians have incorporated an assessment of frailty using the "end-of-the-bed test" or "eyeball test" into their clinical decision making. However, over the last decade, numerous nonspecific and specific tools have emerged. The current evidence supports the use of a combination of simple, user-friendly, objective measures to first identify frailty in ESLD (notably Clinical Frailty Scale, Liver Frailty Index), followed by a combination of serial tools to assess specifically sarcopenia (i.e., muscle ultrasound), physical function (i.e., chair stands, hand grip strength), functional capacity (i.e., 6-minute walk test), and physical disability (i.e., activities of daily living).

Wearables, Physical Activity, and Exercise Testing in Liver Disease

Physical inactivity is a major cause of deterioration in all forms of advanced liver disease. It is especially important as a driver of the components of the metabolic syndrome, with nonalcoholic fatty liver disease rapidly becoming the dominant cause of liver-related death worldwide. Growing realization of the health benefits of moderate-to-vigorous physical activity has captured the interest of persons who desire to improve their health, including those at risk for chronic liver injury. They are increasingly adopting wearable activity trackers to measure the activity that they seek to improve. Improved physical activity is the key lifestyle behavior that can improve cardiorespiratory fitness, which is most accurately measured with cardiopulmonary exercise testing (CPET). CPET is showing promise to identify risk and predict outcomes in transplant hepatology. Team effort among engaged patients, social support networks, and clinicians supported by web-based connectivity is needed to fully exploit the benefits of physical activity tracking.

Markers of Right Ventricular Dysfunction Predict Maximal Exercise Capacity After Left Ventricular Assist Device Implantation

Although left ventricular assist device (LVAD) improves functional capacity, on average LVAD patients are unable to achieve the aerobic capacity of normal healthy subjects or mild heart failure patients. The aim of this study was to examine if markers of right ventricular (RV) function influence maximal exercise capacity. This was a single-center prospective study that enrolled 20 consecutive HeartWare ventricular assist device patients who were admitted at the Freeman Hospital (Newcastle upon Tyne, United Kingdom) for a heart transplant assessment from August 2017 to October 2018. Mean peak oxygen consumption (Peak VO2) was 14.0 ± 5.0 ml/kg/min, and mean peak age and gender-adjusted percent predicted oxygen consumption (%VO2) was 40.0% ± 11.5%. Patients were subdivided into two groups based on the median peak VO2, so each group consisted of 10 patients (50%). Right-sided and pulmonary pressures were consistently higher in the group with poorer exercise tolerance. Patients with poor exercise tolerance (peak VO2 below the median) had higher right atrial pressures at rest (10.6 ± 6.4 vs. 4.3 mmHg ± 3.2; p = 0.02) and the increase with passive leg raising was significantly greater than those with preserved exercise tolerance (peak VO2 above the median). Patients with poor functional capacity also had greater RV dimensions (4.4 cm ± 0.5 vs. 3.7 cm ± 0.5; p = 0.02) and a higher incidence of significant tricuspid regurgitation (moderate or severe tricuspid regurgitation in five patients in the poor exercise capacity group vs. none in the preserved exercise capacity group; p = 0.03). In conclusion, echocardiographic and hemodynamic markers of RV dysfunction discriminate between preserved and nonpreserved exercise capacity in HeartWare ventricular assist device patients.

Frailty and Sarcopenia in Patients Pre- and Post-Liver Transplant

Greater than half of patients with decompensated liver disease suffer from frailty and/or sarcopenia, which can lead to increased pre- and post-liver transplant morbidity and mortality. Although frailty and sarcopenia can impact patients with end-stage liver disease in similar ways, they are unique clinical entities with differing underlying etiologies. Early assessment and identification of frailty and sarcopenia in patients is critical to guide clinical decision-making regarding transplantation and to implement nutritional and exercise-based treatment regiments. Nonetheless, accurate diagnosis and, in particular, predicting patients that will develop frailty and/or sarcopenia remains challenging, and the success of clinical interventions is limited.

Preoperative Evaluation of Coronary Artery Disease in Liver Transplant Candidates: Many Unanswered Questions in Clinical Practice

Cardiovascular (CV) complications represent the first non-graft-related cause of death and the third overall cause of death among patients undergoing liver transplantation (LT). History of coronary artery disease is related to increased CV mortality following LT. Although it is of paramount importance to stratify CV risk in pre-LT patients, there is no consensus regarding the choice of the optimal non-invasive cardiac imaging test. Algorithms proposed by scientific associations include non-traditional risk factors, which are associated with increased cardiac risk profiles. Thus, an individualized pre-LT evaluation protocol should be followed. As the average age of patients undergoing LT and the number of candidates continue to rise, the “3 W” questions still remain unanswered, Who, Which and When? Who should be screened for coronary artery disease (CAD), which screening modality should be used and when should the asymptomatic waitlisted patients repeat cardiac evaluation? Prospective studies with large sample sizes are warranted to define an algorithm that can provide better risk stratification and more reliable survival prediction.

Pre-transplant Sarcopenic Obesity Worsens the Survival After Liver Transplantation: A Meta-Analysis and a Systematic Review

Background: The rising prevalence of cirrhotic cases related to non-alcoholic steatohepatitis has led to an increased number of cirrhotic patients with coexistence of obesity and muscle mass loss, known as sarcopenic obesity (SO). In patients undergoing liver transplantation (LT), the presence of SO may worsen prognosis, and increase morbidity and mortality.

Objective: We aimed to evaluate the effect of the presence of pre-transplant SO on the outcomes of LT.

Methods: A comprehensive search was performed in seven medical databases for studies comparing morbidity and mortality of patients with and without SO after LT. The primary outcome was overall mortality in the short- (1 year), intermediate- (3 years), and long- (5 years) term. We calculated pooled relative risks (RRs) with 95% confidence intervals (CIs). Heterogeneity was quantified with I²-statistics.

Results: Based on the analysis of 1,515 patients from three articles, SO increased overall mortality compared to non-SO at short-, intermediate-, and long-term follow-up (RR = 2.06, 95% CI: 1.28-3.33; RR = 1.67, 95% CI: 1.10-2.51; and RR = 2.08, 95% CI: 1.10-3.93, respectively) without significant between-study heterogeneity for the short- and intermediate- term (I² = 0.0% for both) and considerable heterogeneity for long-term follow-up (I² = 81.1%).

Conclusion: Pre-transplant SO proved to be a risk factor after LT and was associated with two times higher mortality at short- and long- term follow-up. Since SO worsens the prognosis of patients after LT, the inclusion of body composition assessment before LT may help to plan a more individualized nutritional treatment, physiotherapy, and postoperative care and may improve morbidity and mortality.

Why women are not small men: sex-related differences in perioperative cardiopulmonary exercise testing

Background

The use of preoperative cardiopulmonary exercise testing (CPET) to evaluate the risk of adverse perioperative outcomes is increasingly prevalent. CPET-derived information enables personalised perioperative care and enhances shared decision-making. Sex-related differences in physical fitness are reported in non-perioperative literature. However, little attention has been paid to sex-related differences in the context of perioperative CPET.

Aim

We explored differences in the physical fitness variables reported in a recently published multi-centre study investigating CPET before colorectal surgery. We also report the inclusion rate of females in published perioperative CPET cohorts that are shaping guidelines and clinical practice.

Methods

We performed a post hoc analysis of the trial data of 703 patients who underwent CPET prior to major elective colorectal surgery. We also summarised the female inclusion rate in peer-reviewed published reports of perioperative CPET.

Results

Fitness assessed using commonly used perioperative CPET variables—oxygen consumption at anaerobic threshold (AT) and peak exercise—was significantly higher in males than in females both before and after correction for body weight. In studies contributing to the development of perioperative CPET, 68.5% of the participants were male.

Conclusion

To our knowledge, this is the first study to describe differences between males and females in CPET variables used in a perioperative setting. Furthermore, there is a substantial difference between the inclusion rates of males and females in this field. These findings require validation in larger cohorts and may have significant implications for both sexes in the application of CPET in the perioperative setting.

Sport and Exercise in Improving Outcomes After Solid Organ Transplantation: Overview From a UK Meeting

Outcomes after solid organ transplantation continue to improve, but premature loss of life remains a major concern, with death from cerebrovascular disease and cardiovascular disease accounting for around 20% late deaths. There are multiple contributory factors including preexisting, and the posttransplant development of, cardiometabolic conditions (such as hypertension, diabetes mellitus, hyperlipidemia, and obesity). There is accumulating evidence that the regular engagement in exercise is an important factor affecting outcomes before, during, and after transplantation; yet most waitlist candidates and recipients have reduced levels of physical activity. The mechanisms whereby physical activity is associated with better outcomes and a reduction in risk factors for cardiovascular disease are incompletely understood. Attempts to increase physical activity in the transplant population, as in the general population, have had limited success. Use of concepts from Nudge theory provides an evidence-based approach that may help increase physical activity and so reduce premature mortality. Both National and International Transplant Games provide a vehicle for increasing physical activity in this population and may also help to reduce premature death by providing a forum for mutual support for recipients and their families as well as an excellent forum for highlighting the success and impact of organ donation.

Liver transplantation in elderly patients: what do we know at the beginning of 2020?

An aging population has prompted us to evaluate the indications of liver transplantation (LT) in elderly patients more frequently. In this review, we summarize the short- and long-term results after LT in elderly patients and also discuss the criteria used to select patients and how recipient age can challenge current allocation systems. Briefly, the feasibility and early outcomes of LT in elderly patients compare favorably with those of younger patients. Although long-term survival is less than satisfactory, large-scale studies show that the transplant survival benefit is similar for elderly and younger patients. Therefore, age alone does not contraindicate LT; however, screening for cardiopulmonary comorbidities, and asymptomatic malignancies, evaluating nutritional status, and frailty, is crucial to ensure optimal results and avoid futile transplantation.

Exercise and physical activity in cirrhosis: opportunities or perils

Reduced exercise capacity and impaired physical performance are observed in nearly all patients with liver cirrhosis. Physical activity and exercise are physiological anabolic stimuli that can reverse dysregulated protein homeostasis or proteostasis and potentially increase muscle mass and contractile function in healthy subjects. Cirrhosis is a state of anabolic resistance, and unlike the beneficial responses to exercise reported in physiological states, there are few systematic studies evaluating the response to exercise in cirrhosis. Hyperammonemia is a mediator of the liver-muscle axis with net skeletal muscle ammonia uptake in cirrhosis causing signaling perturbations, mitochondrial dysfunction with decreased ATP content, modifications of contractile proteins, and impaired ribosomal function, all of which contribute to anabolic resistance in cirrhosis and have the potential to impair the beneficial responses to exercise. English language-publications in peer-reviewed journals that specifically evaluated the impact of exercise in cirrhosis were reviewed. Most studies evaluated responses to endurance exercise, and readouts included peak or maximum oxygen utilization, grip strength, and functional capacity. Endurance exercise for up to 12 wk is clinically tolerated in well-compensated cirrhosis. Data on the safety of resistance exercise are conflicting. Nutritional supplements enhance the benefits of exercise in healthy subjects but have not been evaluated in cirrhosis. Whether the beneficial physiological responses with endurance exercise and increase in muscle mass with resistance exercise that occur in healthy subjects also occur in cirrhotics is not known. Specific organ-system responses, changes in body composition, or improved long-term clinical outcomes with exercise in cirrhosis need evaluation.

Preoperative cardiac assessment in liver transplant candidates

New and extended indications, older age, higher cardiovascular risk, and the long-standing cirrhosis-associated complications mandate specific skills for an appropriate preoperative assessment of the liver transplant (LT) candidate. The incidence of cardiac diseases (dysrhythmias, cardiomyopathies, coronary artery disease, valvular heart disease) are increasing among LT recipients: however, no consensus exists among clinical practice guidelines for cardiovascular screening and risk stratification. In spite of different "transplant center-centered protocols", basic "pillars" are common (electrocardiography, baseline echocardiography, functional assessment). Owing to intrinsic limitations, yields and relevance of noninvasive stress tests, under constant scrutiny even if used, are discussed, focusing the definition of the "high risk" candidate and exploring noninvasive imaging and new forms of stress imaging. The aim is to find an appropriate and rational stepwise algorithm. The final commitment is to select the right candidate for a finite resource, the graft, able to save (and change) lives.

Cardiopulmonary Exercise Testing for Preoperative Evaluation: What Does the Future Hold?

Purpose of Review

Cardiopulmonary exercise testing (CPET) informs the preoperative evaluation process by providing individualised risk profiles; guiding shared decision-making, comorbidity optimisation and preoperative exercise training; and informing perioperative patient management. This review summarises evidence on the role of CPET in preoperative evaluation and explores the role of novel and emerging CPET variables and alternative testing protocols that may improve the precision of preoperative evaluation in the future.

Recent Findings

CPET provides a wealth of physiological data, and to date, much of this is underutilised clinically. For example, impaired chronotropic responses during and after CPET are simple to measure and in recent studies are predictive of both cardiac and noncardiac morbidity following surgery but are rarely reported. Exercise interventions are increasingly being used preoperatively, and endurance time derived from a high intensity constant work rate test should be considered as the most sensitive method of evaluating the response to training. Further research is required to identify the clinically meaningful difference in endurance time. Measuring efficiency may have utility, but this requires exploration in prospective studies.

Summary

Further work is needed to define contemporaneous risk thresholds, to explore the role of other CPET variables in risk prediction, to better characterise CPET’s role in combination with other tools in multifactorial risk stratification and increasingly to evaluate CPET’s utility for preoperative exercise prescription in prehabilitation.

Frailty, Sarcopenia, and Malnutrition in Cirrhotic Patients

Sarcopenia, frailty, and malnutrition are prevalent complications in patients with end-stage liver disease (ESLD) and are associated with increased risk of morbidity and mortality. It is valuable to measure nutritional status, sarcopenia, and frailty over time in order to create interventions tailored to individuals with ESLD. Evaluating sarcopenia and frailty in patients with ESLD is challenging. Further work is needed to perfect these assessments so that clinicians can incorporate these assessments into their decision-making and management plans for cirrhotic patients.

Frailty and Outcomes After Liver Transplantation

Purpose of review

Frailty is an emerging concept in liver transplantation. We reviewed the literature for the tests of frailty which have been validated to predict outcomes in patients with cirrhosis evaluated for liver transplantation.

Recent findings

Several tools have been developed to further stratify risk of adverse events independent of liver disease severity. These include tests of disability such as activities of daily living and the Karnofsky Performance Score as well as tests of physical frailty such as the Liver Frailty Index (hand-grip, chair stands, and balance).

Summary

Increasingly, the frailty assessment is seen as a critical component of the liver transplant evaluation. Further research is needed to clarify the optimal timing of testing and the implications of longitudinal change.

Physical exercise for people with cirrhosis

BACKGROUND

Loss of muscle mass and muscle weakness are common complications to cirrhosis and are associated with increased morbidity and mortality. Therefore, physical exercise may benefit people with cirrhosis.

OBJECTIVES

To assess the beneficial and harmful effects of physical exercise versus sham exercise or no exercise for people with cirrhosis.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, and three other databases, including manual searches through reference lists, abstracts, and presentations at conferences and meetings, Google Scholar, and online trial registers in February 2018.

SELECTION CRITERIA

We included randomised clinical trials regardless of publication status or language. Inclusion criteria were cirrhosis irrespective of the aetiology or stage. Interventions were physical exercise compared with sham exercise or no intervention.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data. We undertook meta-analyses and presented results using risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes, both with 95% confidence intervals (CI) and I² values as markers of imprecision and heterogeneity. We assessed bias control using the Cochrane Hepato-Biliary Group domains and determined the credibility of the evidence using GRADE.

MAIN RESULTS

We included six randomised clinical trials with 173 participants. All participants had Child-Pugh stage A or B cirrhosis. The intervention groups participated in eight to 14 weeks of physical exercise (aerobic: three trials; resistance: one trial; or aerobic plus resistance training: two trials). Control groups underwent sham exercise (supervised relaxation: one trial) or no intervention (five trials). None of the 89 participants allocated to exercise versus two of 84 participants in the control group died (RR 0.19, 95% CI 0.01 to 3.73; moderate-quality evidence). The cause of death was acute-on-chronic liver disease for both participants. Nine participants in the exercise group and 13 in the control group experienced serious adverse events (RR 0.61, 95% CI 0.19 to 1.94; low-quality evidence).Physical exercise showed no beneficial or detrimental effect on health-related quality of life assessed by the Chronic Liver Disease Questionnaire (MD 0.11, 95% CI -0.44 to 0.67; low-quality evidence). Likewise, physical exercise had no clear effect on physical fitness measured by peak exercise oxygen uptake (MD 0.3 mL/kg/minute, 95 % CI -2.74 to 3.35; low-quality evidence) and Six-Minute Walk Test (MD 56.06 min, 95% CI -9.14 to 121.26; very low-quality evidence). Physical exercise showed no clear effect on mid-thigh circumference (MD 1.76 cm, 95% CI -0.26 to 3.77; low-quality evidence), but showed an increase in mid-arm circumference (MD 2.61 cm, 95% CI 0.36 to 4.85; low-quality evidence).

AUTHORS' CONCLUSIONS

We found no clear beneficial or harmful effect of physical exercise on mortality, morbidity, or health-related quality of life. Further evidence is needed to evaluate the beneficial and harmful effects of physical exercise on clinical outcomes.

Elevated alveolar nitric oxide is linked to poor aerobic capacity and chronotropic incompetence in liver transplant candidates

BACKGROUND & AIMS

Increased nitric oxide is involved in abnormal hemodynamic parameters and respiratory function of cirrhotic patients. We aimed to quantify partitioning exhaled nitric oxide measurements in exhaled air in liver transplantation (LT) candidates and evaluate their relationships with chronotropic incompetence and aerobic capacity.

METHODS

We compared exhaled nitric oxide (NO) measurements, heart rate response and peak oxygen uptake during incremental exercise in liver transplantation candidates to those of controls.

RESULTS

As opposed to healthy control subjects, LT candidates displayed elevated alveolar NO, blunted chronotropic response and reduced V'O₂ at maximal exercise. In LT candidates, median peak V'O₂ was 18.7 ml kg^-1 min^-1 (interquartile range (IQR) 16.2; 21.8), corresponding to 65% (IQR 57; 72) of the predicted value. Compared with controls, LT candidates had increased levels of alveolar NO (median (IQR) 2.0 (1.2; 2.2) versus 3.1 (2.3; 4.5), p < 0.001). In controls, no relations were found between alveolar NO and V'O₂ peak or heart rate reserve whereas in cirrhotic patients, negative correlations and negative slopes were found between alveolar NO and V'O₂ peak and heart rate reserve decrease.

CONCLUSIONS

Increasing alveolar NO could be a specific pathophysiological condition limiting aerobic capacity in LT candidates.

Physical frailty after liver transplantation

Frailty is prevalent in liver transplant candidates, but little is known of what happens to frailty after liver transplantation. We analyzed data for 214 adult liver transplant recipients who had ≥1 frailty assessment using the Liver Frailty Index (LFI) at 3- (n = 178), 6- (n = 139), or 12- (n = 107) months posttransplant (higher values=more frail). "Frail" and "robust" were defined as LFI ≥4.5 and <3.2. Median pre-liver transplant LFI was 3.7, and was worse at 3 months (3.9; P = .02), similar at 6 months (3.7; P = .07), and improved at 12 months (3.4; P < .001). The percentage who were robust pre- and 3-, 6-, and 12-months posttransplant were 25%, 14%, 28%, and 37%; the percentage frail were 21%, 21%, 10%, and 7%. In univariable analysis, each 0.1 pretransplant LFI point more frail was associated with a decreased odds of being robust at 3- (odds ratio [OR] 0.75), 6- (OR 0.77), and 12-months (OR 0.90) posttransplant (P ≤ .001), which did not change substantially with multivariable adjustment. In conclusion, frailty worsens 3 months posttransplant and improves modestly by 12 months, but fewer than 2 of 5 patients achieve robustness. Pretransplant LFI was a potent predictor of posttransplant robustness. Aggressive interventions aimed at preventing frailty pretransplant are urgently needed to maximize physical health after liver transplantation.

Cardiopulmonary Exercise Testing and Surgery

The surgical patient population is increasingly elderly and comorbid and poses challenges to perioperative physicians. Accurate preoperative risk stratification is important to direct perioperative care. Reduced aerobic fitness is associated with increased postoperative morbidity and mortality. Cardiopulmonary exercise testing is an integrated and dynamic test that gives an objective measure of aerobic fitness or functional capacity and identifies the cause of exercise intolerance. Cardiopulmonary exercise testing provides an individualized estimate of patient risk that can be used to predict postoperative morbidity and mortality. This technology can therefore be used to inform collaborative decision-making and patient consent, to triage the patient to an appropriate perioperative care environment, to diagnose unexpected comorbidity, to optimize medical comorbidities preoperatively, and to direct individualized preoperative exercise programs. Functional capacity, evaluated as the anaerobic threshold and peak oxygen uptake ([Formula: see text]o₂peak) predicts postoperative morbidity and mortality in the majority of surgical cohort studies. The ventilatory equivalents for carbon dioxide (an index of gas exchange efficiency), is predictive of surgical outcome in some cohorts. Prospective cohort studies are needed to improve the precision of risk estimates for different patient groups and to clarify the best combination of variables to predict outcome. Early data suggest that preoperative exercise training improves fitness, reduces the debilitating effects of neoadjuvant chemotherapy, and may improve clinical outcomes. Further research is required to identify the most effective type of training and the minimum duration required for a positive effect.

Interventions to improve physical function and prevent adverse events in cirrhosis

Cirrhosis is associated with debilitating complications that significantly impact on a patient’s physical function and reduce quality of life. Owing to highly prevalent sarcopenia, malnutrition and hepatic encephalopathy, functional impairment or frailty is a common complication of cirrhosis. Frailty in turn increases the patient’s risk of hospitalization, accidental falls and fractures, and death. The management of frailty and its associated adverse effects is imperative in improving the overall prognosis of patients with advanced liver disease. The cornerstone of therapy revolves around optimizing physical function with appropriate nutrition and exercise. Nutritional therapy with protein supplementation has shown significant benefit, while studies on exercise have been controversial. However, newly emerging studies trend towards a beneficial effect of physical exercise with improvement in quality of life. The implementation of technology in liver disease management shows future promise. Fitbits and other wearable devices can be used to help monitor a patient’s personal progress in physical exercise and nutritional optimization. Additionally, the progressive development of new smartphone applications to help aid in the diagnosis and monitoring of complications of cirrhosis provides a sophisticated avenue for improving care of patients with cirrhosis.

Home Exercise Training Improves Exercise Capacity in Cirrhosis Patients: Role of Exercise Adherence

Cirrhosis patients have reduced peak aerobic power (peak VO₂) that is associated with reduced survival. Supervised exercise training increases exercise tolerance. The effect of home-based exercise training (HET) in cirrhosis is unknown. The objective was to evaluate the safety and efficacy of 8 weeks of HET on peak VO₂, 6-minute walk distance (6MWD), muscle mass, and quality of life in cirrhosis. Random assignment to 8 weeks of HET (moderate to high intensity cycling exercise, 3 days/week) or usual care. Exercise adherence defined as completing ≥80% training sessions. Paired t-tests and analysis of covariance used for comparisons. Forty patients enrolled: 58% male, mean age 57 y, 70% Child Pugh-A. Between group increases in peak VO₂ (1.7, 95% CI: −0.33 to 3.7 ml/kg/min, p = 0.09) and 6MWD (33.7, 95% CI: 5.1 to 62.4 m, p = 0.02) were greater after HET versus usual care. Improvements even more marked in adherent subjects for peak VO₂ (2.8, 95% CI: 0.5–5.2 mL/kg/min, p = 0.02) and 6MWD (46.4, 95% CI: 12.4–80.5 m, p = 0.009). No adverse events occurred during testing or HET. Eight weeks of HET is a safe and effective intervention to improve exercise capacity in cirrhosis, with maximal benefits occurring in those who complete ≥80% of the program.

Preoperative optimization for major hepatic resection

PURPOSE

Major hepatic resections are performed for primary hepatobiliary malignancies, metastatic disease, and benign lesions. Patients with chronic liver disease, including cirrhosis and steatosis, are at an elevated risk of malnutrition and impaired strength and exercise capacity, deficits which cause increased risk of postoperative complications and mortality. The aims of this report are to discuss the pathophysiology of changes in nutrition, exercise capacity, and muscle strength in patient populations likely to require major hepatectomy, and review recommendations for preoperative evaluation and optimization.

METHODS

Nutritional and functional impairment in preoperative hepatectomy patients, especially those with underlying liver disease, have a complex and multifactorial physiologic basis that is not completely understood.

RESULTS

Recognition of malnutrition and compromised strength and exercise tolerance preoperatively can be difficult, but is critical in providing the opportunity to intervene prior to major hepatic resection and potentially improve postoperative outcomes. There is promising data on a variety of nutritional strategies to ensure adequate intake of calories, proteins, vitamins, and minerals in patients with cirrhosis and reduce liver size and degree of fatty infiltration in patients with hepatic steatosis. Emerging evidence supports structured exercise programs to improve exercise tolerance and counteract muscle wasting.

CONCLUSIONS

The importance of nutrition and functional status in patients indicated for major liver resection is apparent, and emerging evidence supports structured preoperative preparation programs involving nutritional intervention and exercise training. Further research is needed in this field to develop optimal protocols to evaluate and treat this heterogeneous cohort of patients.

Impact of beta-blockers on cardiopulmonary exercise testing in patients with advanced liver disease

BACKGROUND

Patients with advanced liver disease may develop portal hypertension that can result in variceal haemorrhage. Beta-blockers reduce portal pressure and minimise haemorrhage risk. These medications may attenuate measures of cardiopulmonary performance, such as the ventilatory threshold and peak oxygen uptake measured via cardiopulmonary exercise testing.

AIM

To determine the effect of beta-blockers on cardiopulmonary exercise testing variables in patients with advanced liver disease.

METHODS

This was a cross-sectional analysis of 72 participants who completed a cardiopulmonary exercise test before liver transplantation. All participants remained on their usual beta-blocker dose and timing prior to the test. Variables measured during cardiopulmonary exercise testing included the ventilatory threshold, peak oxygen uptake, heart rate, oxygen pulse, the oxygen uptake efficiency slope and the ventilatory equivalents for carbon dioxide slope.

RESULTS

Participants taking beta-blockers (n = 28) had a lower ventilatory threshold (P <.01) and peak oxygen uptake (P = .02), compared to participants not taking beta-blockers. After adjusting for age, the model of end-stage liver-disease score, liver-disease aetiology, presence of refractory ascites and ventilatory threshold remained significantly lower in the beta-blocker group (P = .04). The oxygen uptake efficiency slope was not impacted by beta-blocker use.

CONCLUSIONS

Ventilatory threshold is reduced in patients with advanced liver disease taking beta-blockers compared to those not taking the medication. This may incorrectly risk stratify patients on beta-blockers and has implications for patient management before and after liver transplantation. The oxygen uptake efficiency slope was not influenced by beta-blockers and may therefore be a better measure of cardiopulmonary performance in this patient population.

Aerobic capacity mediates susceptibility for the transition from steatosis to steatohepatitis

KEY POINTS

Low intrinsic aerobic capacity is associated with increased all-cause and liver-related mortality in humans. Low intrinsic aerobic capacity in the low capacity runner (LCR) rat increases susceptibility to acute and chronic high-fat/high-sucrose diet-induced steatosis, without observed increases in liver inflammation. Addition of excess cholesterol to a high-fat/high-sucrose diet produced greater steatosis in LCR and high capacity runner (HCR) rats. However, the LCR rat demonstrated greater susceptibility to increased liver inflammatory and apoptotic markers compared to the HCR rat. The progressive non-alcoholic fatty liver disease observed in the LCR rats following western diet feeding was associated with further declines in liver fatty acid oxidation and mitochondrial respiratory capacity compared to HCR rats.

ABSTRACT

Low aerobic capacity increases risk for non-alcoholic fatty liver disease and liver-related disease mortality, but mechanisms mediating these effects remain unknown. We recently reported that rats bred for low aerobic capacity (low capacity runner; LCR) displayed susceptibility to high fat diet-induced steatosis in association with reduced hepatic mitochondrial fatty acid oxidation (FAO) and respiratory capacity compared to high aerobic capacity (high capacity runner; HCR) rats. Here we tested the impact of aerobic capacity on susceptibility for progressive liver disease following a 16-week 'western diet' (WD) high in fat (45% kcal), cholesterol (1% w/w) and sucrose (15% kcal). Unlike previously with a diet high in fat and sucrose alone, the inclusion of cholesterol in the WD induced hepatomegaly and steatosis in both HCR and LCR rats, while producing greater cholesterol ester accumulation in LCR compared to HCR rats. Importantly, WD-fed low-fitness LCR rats displayed greater inflammatory cell infiltration, serum alanine transaminase, expression of hepatic inflammatory markers (F4/80, MCP-1, TLR4, TLR2 and IL-1β) and effector caspase (caspase 3 and 7) activation compared to HCR rats. Further, LCR rats had greater WD-induced decreases in complete FAO and mitochondrial respiratory capacity. Intrinsic aerobic capacity had no impact on WD-induced hepatic steatosis; however, rats bred for low aerobic capacity developed greater hepatic inflammation, which was associated with reduced hepatic mitochondrial FAO and respiratory capacity and increased accumulation of cholesterol esters. These results confirm epidemiological reports that aerobic capacity impacts progression of liver disease and suggest that these effects are mediated through alterations in hepatic mitochondrial function.

Anaesthesia for liver transplantation

Liver transplantation is a complex procedure that requires a truly multidisciplinary team approach with anaesthetic involvement from the outset in order to ensure excellent outcomes. Before a patient is placed on the waiting list for a liver transplant, a thorough evaluation is undertaken and his/her suitability for transplantation discussed in a patient selection committee meeting. The perioperative management of patients requiring transplantation can be challenging because of the systemic implications of liver disease, approaches to surgical technique and the quality of the grafts used; an increase in the use of marginal donor organs to meet the organ demand poses its own unique difficulties.

Evaluation of coronary artery disease in potential liver transplant recipients

Improvements in the management of patients undergoing liver transplantation (LT) have resulted in a significant increase in survival in recent years. Cardiac disease is now the leading cause of early mortality, and the stress of major surgery, hemodynamic shifts, and the possibilities of hemorrhage or reperfusion syndrome require the recipient to have good baseline cardiac function. The prevalence of coronary artery disease (CAD) is increasing in LT candidates, especially in those with nonalcoholic fatty liver disease. In assessing LT recipients, we suggest a management paradigm of "quadruple assessment" to include (1) history, examination, and electrocardiogram; (2) transthoracic echocardiogram; (3) functional testing; and (4) where appropriate, direct assessment of CAD. The added value of functional testing, such as cardiopulmonary exercise testing, has been shown to be able to predict posttransplant complications independently of the presence of CV disease. This approach gives the assessment team the greatest chance of detecting and preventing complications related to CAD. Liver Transplantation 23 386-395 2017 AASLD.

Patient-perceived barriers to lifestyle interventions in cirrhosis

BACKGROUND/AIMS

Sarcopenia, muscle weakness, and physical frailty are independent predictors of mortality in cirrhosis. These adverse prognostic factors are potentially modifiable with lifestyle interventions, including adequate nutritional intake and physical activity. Our aim was to identify patient-perceived barriers and enablers to these interventions.

PATIENTS AND METHODS

Adult patients with cirrhosis were prospectively recruited from two tertiary care liver clinics. Patients were excluded if they had hepatocellular carcinoma beyond transplant criteria, other active malignancy, or advanced chronic disease.

RESULTS

A total of 127 patients (mean age: 60 ± 9 years, 58% males, and 48% with Child-Pugh-B/C (CP-B/C) disease) were included. Two-thirds of the patients had cirrhosis related to alcohol or hepatitis C. CP-B/C patients were more likely to take oral nutritional supplements (56% vs 29%) and less likely to consume animal protein daily (66% vs 85%) when compared to CP-A patients. Early satiety, altered taste, and difficulty in buying/preparing meals were more common in CP-B/C patients and even present in 20-30% of CP-A patients. Most patients reported adequate funds to purchase food. As quantified by the International Physical Activity Questionnaire-Short Form, 47% reported low activity levels, with no significant differences between groups. CP-B/C patients were more fatigued with exercise, however, overall Exercise Benefits/Barriers Scale scores were similar across groups.

CONCLUSIONS

Barriers to nutritional intake and physical activity are common in cirrhosis and should be evaluated and treated in all patients. Asking simple screening questions in clinic and referring at-risk patients to expert multidisciplinary providers is a reasonable strategy to address these barriers. Future research should evaluate techniques to overcome modifiable barriers and enhance enablers.

Malnutrition and sarcopenia predict post-liver transplantation outcomes independently of the Model for End-stage Liver Disease score

BACKGROUND

Although malnutrition and sarcopenia are prevalent in cirrhosis, their impact on outcomes following liver transplantation is not well documented.

METHODS

The associations of nutritional status and sarcopenia with post-transplant infections, requirement for mechanical ventilation, intensive care (ICU) and hospital stay, and 1 year mortality were assessed in 232 consecutive transplant recipients. Nutritional status and sarcopenia were assessed using the Royal Free Hospital-Global Assessment (RFH-GA) tool and the L3-psoas muscle index (L3-PMI) on CT, respectively.

RESULTS

A wide range of RFH-SGA and L3-PMI were observed within similar Model for End-stage Liver Disease (MELD) sub-categories. Malnutrition and sarcopenia were independent predictors of all outcomes. Post-transplant infections were associated with MELD (OR = 1.055, 95%CI = 1.002-1.11) and severe malnutrition (OR = 6.55, 95%CI = 1.99-21.5); ventilation > 24 h with MELD (OR = 1.1, 95%CI = 1.036-1.168), severe malnutrition (OR = 8.5, 95%CI = 1.48-48.87) and suboptimal donor liver (OR = 2.326, 95%CI = 1.056-5.12); ICU stay > 5 days, with age (OR = 1.054, 95%CI = 1.004-1.106), MELD (OR = 1.137, 95%CI = 1.057-1.223) and severe malnutrition (OR = 7.46, 95%CI = 1.57-35.43); hospital stay > 20 days with male sex (OR = 2.107, 95%CI = 1.004-4.419) and L3-PMI (OR = 0.996, 95%CI = 0.994-0.999); 1 year mortality with L3-PMI (OR = 0.996, 95%CI = 0.992-0.999). Patients at the lowest L3-PMI receiving suboptimal grafts had longer ICU/hospital stay and higher incidence of infections.

CONCLUSIONS

Malnutrition and sarcopenia are associated with early post-liver transplant morbidity/mortality. Allocation indices do not include nutritional status and may jeopardize outcomes in nutritionally compromised individuals.

Coronary Computed Tomography Angiography in Combination with Coronary Artery Calcium Scoring for the Preoperative Cardiac Evaluation of Liver Transplant Recipients

Liver transplantation is the best treatment option for early-stage hepatocellular carcinoma, liver cirrhosis, fulminant liver failure, and end-stage liver diseases. Even though advances in surgical techniques and perioperative care have improved postoperative outcomes, perioperative cardiovascular complications are a leading cause of postoperative morbidity and mortality following liver transplantation. Ischemic coronary artery disease (CAD) and cardiomyopathy are the most common cardiovascular diseases and could be negative predictors of postoperative outcomes in liver transplant recipients. Therefore, comprehensive cardiovascular evaluations are required to assess perioperative risks and prevent concomitant cardiovascular complications that would preclude good outcomes in liver transplant recipients. The two major types of cardiac computed tomography are the coronary artery calcium score (CACS) and coronary computed tomography angiography (CCTA). CCTA in combination with the CACS is a validated noninvasive alternative to coronary angiography for diagnosing and grading the severity of CAD. A CACS > 400 is associated with significant CAD and a known important predictor of posttransplant cardiovascular complications in liver transplant recipients. In this review article, we discuss the usefulness, advantages, and disadvantages of CCTA combined with CACS as a noninvasive diagnostic tool for preoperative cardiac evaluation and for maximizing the perioperative outcomes of liver transplant recipients.