Physical inactivity is highly prevalent after solid organ transplantation and leads to unfavourable outcomes. This review aimed to understand posttransplant physical activity behaviour and propose physical activity interventions. Michie’s Behavioural Change Wheel was applied, in which the Context and Implementation of Complex Interventions framework, the Capability-Opportunity-Motivation and Behaviour model, and the Theoretical Domains Framework were embedded. Various contextual factors were found to modulate physical activity behaviour. Promising strategies to promote long-term physical activity included (i) tailoring of physical activity programs to patients’ abilities and preferences; (ii) incitement of intrinsic and autonomous motivation to change; (iii) SMART goals setting (e.g., Specific, Measurable, Achievable, Realistic, Timebound), (iv) autonomy-supportive co-design of action plans; (v) foster new habit formation; (vi) self-monitoring of physical activity; (vii) follow-up opportunities for evaluation and adjustment; (viii) education of transplant recipients, healthcare providers, and the patients’ social network; (iv) improvement of self-efficacy through incremental successes, verbal persuasion, peer modelling, and awareness of exercise-related bodily signals; (x) providing physical activity opportunity within patients’ social and environmental setting; (xi) encouragement and support from patients’ social network and healthcare providers; and (xii) governmental action that alleviates financial barriers and restructures the physical environment to promote physical activity. These new insights may contribute to physical activity program development for transplantation recipients.

Sarcopenia occurs in 30-70% of patients with end-stage liver disease and is associated with inferior pre- and post-liver transplant outcomes such as prolonged intubation times, long intensive care and hospitalization times, heightened risk of post-transplant infection, reduced health-related quality of life, and increased rates of mortality. The pathogenesis of sarcopenia is multifactorial and involves biochemical disturbances such as hyperammonemia, low serum concentrations of branched-chain amino acids (BCAAs) and low serum levels of testosterone, as well as chronic inflammation, inadequate nutritional status, and physical inactivity. Prompt recognition and accurate assessment of sarcopenia are critical and require imaging, dynamometry, and physical performance testing for the assessment of its subcomponents: muscle mass, muscle strength, and muscle function, respectively. Liver transplantation mostly fails to reverse sarcopenia in sarcopenic patients. In fact, some patients develop de novo sarcopenia after undergoing liver transplantation. The recommended treatment of sarcopenia is multimodal and includes a combination of exercise therapy and complementary nutritional interventions. Additionally, new pharmacological agents (e.g. myostatin inhibitors, testosterone supplements, and ammonia-lowering therapy) are under investigation in preclinical studies. Here, we present a narrative review of the definition, assessment, and management of sarcopenia in patients with end-stage liver disease prior to and after liver transplantation.

BACKGROUND AND AIMS Advances in the field of kidney transplantation have led to improved postoperative survival rates, but age-standardized mortality nonetheless remains 2- to 7-fold higher in kidney transplant recipients—with cardiovascular disease representing the leading cause of death in recipients with a functioning graft. Poor physical fitness, not completely recovering after transplantation, adds to the heightened cardiovascular risk of hypertension, diabetes, dyslipidemia and obesity. So does the post-transplant continuation of gut microbial dysbiosis, which recently emerged as a modulator of muscular, metabolic and cardiovascular health. Exercise-based rehabilitation and physical activity interventions may prove pivotal in the care of kidney transplant recipients to address aforementioned outcomes. METHOD At 3 months post-transplant, a probability sample of 147 adult kidney transplant recipients from two independent Belgian transplant centers will be randomly allocated to either 6 months of home-based moderate-intensity training (MIT, n = 49), concurrent moderate- and high-intensity training (MHIT, n = 49) or usual care (CON, n = 49) (Figure1). High-intensity training sessions in MHIT are based on the Scandinavian model (four blocks of 4 min at high intensity interspersed by 3 min of active recovery), performed twice a week, and of equivalent energy expenditure as moderate-intensity training (Figure2). MIT and MHIT will perform similar muscle strengthening exercises, twice a week. The training intervention will be followed by an individualized activity intervention aiming for long-term physical activity maintenance in MIT and MHIT; using motivational interviewing techniques, co-creation of an action plan adapted to the patients’ preferences, goal-setting, gradually decreasing follow-up prompts over time and self-monitoring of physical activity behavior. Study participants will be followed-up till 2 years after transplantation. We hypothesize that the study intervention will improve our primary outcome cardiorespiratory fitness, assessed as peak oxygen uptake, at 9 months post-transplant. Secondary outcomes include muscle fitness, motor fitness, body composition, cardiovascular health, gut microbiome characteristics, health-related quality of life, safety, cost-effectiveness and implementation outcomes (Figure1). The role of training intensity and the role of baseline gut microbiome characteristics as predictor of individuals’ training response will be explored. RESULTS Results from this two-phased RCT will provide novel insights in the safety, implementation potential, cost-effectiveness and effectiveness of a home-based exercise program and physical activity intervention in de novo kidney transplant recipients to improve physical fitness, cardiovascular health, gut microbiome characteristics and health-related quality of life. CONCLUSION PHOENIX-kidney represents the first adequately powered multicenter RCT evaluating basic, clinical and health-economic outcome parameters in response to an exercise training and physical activity intervention in kidney transplant recipients.

Objective: Carotid-femoral pulse wave velocity (cf-PWV) is considered the gold-standard measure for arterial stiffness. The SphygmoCor CVMS uses applanation tonometry on the carotid and femoral arteries, synchronized with an ECG signal. The more recent SphygmoCor XCEL eliminates the need for ECG gating by utilizing leg cuff detection of the femoral pulse in conjunction with carotid tonometry. The latter method is more time-efficient, but may yield different cf-PWV values. The aim of this pilot study is to validate the use of the SphygmoCor XCEL against the SphygmoCor CVMS. Design and method: Measurements of the right carotid and femoral artery were conducted using the SphygmoCor CVMS (AtCor Medical), immediately followed by the SphygmoCor XCEL (AtCor Medical). These measurements were performed under standardized conditions, namely in a fasted state and after 15 minutes of rest in a supine position in a quiet room (20̊). All measurements were done in triplicate and were repeated when they did not meet the quality control guidelines, as defined by the manufacturer. The mean difference and SD of the difference between the two devices was calculated and visualized through scatter plot and Bland-Altman analysis. Correlation coefficient as well as intraclass correlation (ICC) was calculated. Results: A total of nine (5 females) non-smoking, physically active individuals were included, with a MEDIAN age of 21 years (21-36) and MEDIAN BMI of 21.8 (18,4-25,8). Mean cf-PWV measured by SphygmoCor CVMS was 8.11 ± 0.69 m/s and by SphygmoCor XCEL was 7.61 ± 0.16 m/s. Measurements by both techniques were significantly correlated (R = 0,75; P<0,05; Fig1). The mean difference between the two measurement techniques was 0.50 ± 0.81 m/s, which is ‘acceptable’ according to the ARTERY Society guidelines. Bland-Altman analysis revealed limits of agreement ranging from -1.09 to 2.09 m/s. A ‘moderate’ agreement was documented (ICC = 0.51). Conclusions: In this pilot study, the SphygmoCor XCEL demonstrated acceptable agreement with the SphygmoCor CVMS. Bland-Altman plots show that with higher cf-PWV values, there could be a tendency towards overestimation of the cf-PWV by the SphygmoCor EXCEL. Further validation is needed in larger cohorts and other populations.