Exercise Prescription in Renal Transplant Recipients: From Sports Medicine Toward Multidisciplinary Aspects: A Pilot Study

Supervised vs home-based exercise program in kidney transplant recipients: A pilot pragmatic non-randomized study

BACKGROUND

Although the benefits of exercise for kidney transplant recipients (KTRs) have been widely demonstrated, these patients experience several barriers in undertaking a structured exercise program in hospital and non-hospital facilities.

AIM

To compare the effects of a supervised moderate-intensity gym-based intervention with a home-based low-intensity walking program on exercise capacity in KTRs.

METHODS

KTRs were asked to choose between two six-month programs. The first group performed a low-intensity interval walking intervention at home-based exercise intervention (HBex). The second group performed a supervised training program at an adapted physical activity gym (Sgym), including aerobic and resistance training. The outcomes, collected at baseline and at the end of the programs, included the 6-minute walking test, the peak oxygen consumption (VO2peak) during a treadmill test, the 5-time sit-to-stand test, and blood pressure.

RESULTS

Seventeen patients agreed to participate and self-selected into the HBex (n = 9) and Sgym (n = 8) groups. Two patients in the Sgym group dropped out because of familial problems. At baseline, patients in the HBex group were significantly older and had lower walking distance, VO2peak, and lower limb strength. Primary outcome changes were significantly greater in the HBex group than in the Sgym group (52 ± 23 m vs 8 ± 34; P = 0.005). No other significant differences between groups were observed. Both groups improved most of the outcomes in the within-group comparisons, with significant variations in VO2 peak.

CONCLUSION

Six-month moderate-intensity supervised or low-intensity home-based training programs effectively improved exercise capacity in KTRs. Gym-based programs combine aerobic and resistance training; however, in-home walking may be proposed for frail KTRs.

Unsupervised Exercise Intervention vs. Adherence to a Mediterranean Diet Alone: The Role of Bioelectrical Impedance Vector Analysis and Cardiovascular Performance in Liver-Transplanted Recipients

(1) Background: Cardiovascular disease is one of the leading causes of mortality after liver transplantation. Body composition and cardiovascular performance assessment represent a potential approach for modulating lifestyle correction and proper follow-up in chronic disease patients. This study aimed to verify the additional role of an unsupervised physical activity program in a sample of male liver transplant recipients who follow the Mediterranean diet. (2) Methods: Thirty-three male liver transplant recipients were enrolled. Sixteen subjects followed a moderate-intensity home exercise program in addition to nutritional support, and seventeen received advice on the Mediterranean diet. After six months, bioelectrical vector impedance analysis (BIVA) and cardiopulmonary exercise testing (CPET) were performed. (3) Results: No differences in CPET (VO2 peak: exercise 21.4 ± 4.1 vs. diet 23.5 ± 6.5 mL/kg/min; p = 0.283) and BIVA (Z/H: exercise 288.3 ± 33.9 vs. diet 310.5 ± 34.2 Ω/m; p = 0.071) were found. Furthermore, the BIVA values of resistance correlate with the submaximal performance of the Ve/VCO2 slope (R = 0.509; p < 0.05) and phase angle with the maximal effort of the VO2 peak (R = 0.557; p < 0.05). (4) Conclusions: Unsupervised physical exercise alone for six months does not substantially modify liver transplant recipients' cardiovascular performance and hydration status, despite their adherence to a Mediterranean diet. The body composition analysis is useful to stratify the risk profile, and it is potentially associated with better outcomes in transplanted subjects.

Flow Dynamic Pattern in Liver and Renal Transplantation under Exercise Prescription Program

BACKGROUND

Cardiovascular diseases in the context of renal and liver transplants remain the leading cause of morbidity and mortality. Physical exercise at a moderate intensity is allowed to contrast the risk profile. Echocardiographic evaluation is essential to stratifying potential cardiotoxicity by the standard and, more recently, the deformation and dynamic study of the intracardiac vortex. This study aims to investigate the vortex echo parameters of solid-organ-transplanted subjects who are physically active compared to a control group of healthy subjects.

METHODS

A group of 33 transplanted subjects (16 kidneys and 17 livers) was studied via a transthoracic echocardiography exam, comprehending the myocardial deformation parameters of global longitudinal strain (GLS), twisting of the left ventricle (LV) chamber, and HyperDoppler image acquisition.

RESULTS

The subjects enrolled in this study were 50 in total: there were 33 transplanted and 17 healthy subjects. The transplanted subjects presented higher values of interventricular septum in diastole (IVSd p = 0.001), posterior wall diastolic (PWd p = 0.05), and left ventricle mass index (LVMI p = 0.029); ejection fraction (EF) was found to be higher in athletes (p < 0.001). Transplanted subjects presented mild diastolic dysfunction, emerging only from septal E values (p = 0.001). The 4DStrain (p = 0.018) and GLS2c (p = 0.017) were significantly better in the athletes. All of the geometrical and energetical vortex data were in the normal range and no significant differences were found. An interesting positive correlation was evident for the diastolic parameter, particularly the E/A ratio (p = 0.023) and E' septal value (p = 0.049), along with the vorticity fluctuation. This behavior was present for all subjects, particularly those that were transplanted (p = 0.005).

CONCLUSIONS

In the vortex investigation, especially in cases of normal EF, the positive correlation of some diastolic parameters with the flow dynamic patterns corroborates this hypothesis. The HyperDoppler analysis could be helpful to detecting potential damage earlier in the diastolic time before a systolic deficiency.

Obesity and Lifestyle Habits among Kidney Transplant Recipients

Background: Obesity may negatively impact clinical outcomes in kidney transplant (KT) recipients. Limited information is available on the prevalence of obesity in this population, and on the lifestyle habits associated with obesity. Methods: we conducted an online, anonymous survey to assess of the proportion of KT recipients with obesity, adherence to the Mediterranean diet (i.e., a dietary regimen with proven renal and cardiovascular outcomes) using the MEDI-Lite questionnaire, and level of physical activity using the International Physical Activity Questionnaire (IPAQ) short form among KT recipients. Results: 255 KT recipients participated. Median (25th−75th quartile) age was 56.0 (48.0; 62.0) years, 43.9% female, median BMI 23.9 (21.6; 26.5) kg/m2. The proportion of KT recipients with obesity was 9.8% (95% confidence interval, 6.4 to 14.1%). Adequate adherence to the Mediterranean diet (Medi-Lite score >9) was overall low (44.7%; 40.0 vs. 45.2% in those with or without obesity, respectively; p = 0.618). In participants with obesity the Medi-Lite score inversely correlated with BMI (R = −0.45; p < 0.025). Overall, 30.6% of participants had a low level of physical activity (44.0 vs. 29.1% of those with or without obesity, respectively; p = 0.125). The amount of energy expended walking was significantly lower among participants with obesity (462 (0.0; 1436) vs. 1056 (433; 2005) METs/week, p = 0.017). Conclusions: the burden of obesity among KT recipients is similar to that of the general population. Adherence to the Mediterranean diet was generally low, and nearly one-third of participants had a low level of physical activity. Building specialized multidisciplinary teams to manage obesity in KT recipients is urgently needed.

The effect of exercise on left ventricular global longitudinal strain

Exercise improves measures of cardiovascular (CV) health and function. But as traditional measures improve gradually, it can be difficult to identify the effectiveness of an exercise intervention in the short-term. Left ventricular global longitudinal strain (LVGLS) is a highly sensitive CV imaging measure that detects signs of myocardial dysfunction prior to more traditional measures, with reductions in LVGLS a strong prognostic indicator of future CV dysfunction and mortality. Due to its sensitivity, LVGLS may offer useful method of tracking the effectiveness of an exercise intervention on CV function in the short-term, providing practitioners useful information to improve patient care in exercise settings. However, the effect of exercise on LVGLS is unclear. This systematic review and meta-analysis aimed to determine the effect exercise has on LVGLS across a range of populations. Included studies assessed LVGLS pre-post an exercise intervention (minimum 2 weeks) in adults 18 years and over, and were published in English from 2000 onwards. Study-level random-effects meta-analyses were performed using Stata (v16.1) to calculate summary standardized mean differences (SMD) and 95% confidence intervals (CI). 39 studies met selection criteria, with 35 included in meta-analyses (1765 participants). In primary analyses, a significant improvement in LVGLS was observed in populations with CV disease (SMD = 0.59; 95% CI 0.16-1.02; p = 0.01), however, no significant effect of exercise was observed in CV risk factor and healthy populations. In populations with CV disease, LVGLS could be used as an early biomarker to determine the effectiveness of an exercise regime before changes in other clinical measures are observed.

Feasibility and acceptability of high-intensity interval training and moderate-intensity continuous training in kidney transplant recipients: the PACE-KD study

Background

Kidney transplant recipients (KTRs) exhibit unique elevated inflammation, impaired immune function, and increased cardiovascular risk. Although exercise reduces cardiovascular risk, there is limited research on this population, particularly surrounding novel high-intensity interval training (HIIT). The purpose of this pilot study was to determine the feasibility and acceptability of HIIT in KTRs.

Methods

Twenty KTRs (male 14; eGFR 58±19 mL/min/1.73 m²; age 49±11 years) were randomised and completed one of three trials: HIIT A (4-, 2-, and 1-min intervals; 80–90% watts at V̇O_2peak), HIITB (4×4 min intervals; 80–90% V̇O_2peak) or MICT (~40 min; 50–60% V̇O_2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 weeks) and followed up for 3 months. Feasibility was assessed by recruitment, retention, and intervention acceptability and adherence.

Results

Twenty participants completed the intervention, and 8 of whom achieved the required intensity based on power output (HIIT A, 0/6 [0%]; HIITB, 3/8 [38%]; MICT, 5/6 [83%]). Participants completed 92% of the 24 sessions with 105 cancelled and rescheduled sessions and an average of 10 weeks to complete the intervention. Pre-intervention versus post-intervention V̇O_2peak (mL/kg^-1/min^-1) was 24.28±4.91 versus 27.06±4.82 in HIITA, 24.65±7.67 versus 27.48±8.23 in HIIT B, and 29.33±9.04 versus 33.05±9.90 in MICT. No adverse events were reported.

Conclusions

This is the first study to report the feasibility of HIIT in KTRs. Although participants struggled to achieve the required intensity (power), this study highlights the potential that exercise has to reduce cardiovascular risk in KTRs. HIIT and MICT performed on a cycle, with some modification, could be considered safe and feasible in KTRs. Larger scale trials are required to assess the efficacy of HIIT in KTRs and in particular identify the most appropriate intensities, recovery periods, and session duration. Some flexibility in delivery, such as incorporating home-based sessions, may need to be considered to improve recruitment and retention.

Trial registration

ISRCTN, ISRCTN17122775. Registered on 30 January 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01067-3.

Exercise Prescription Guidelines for Cardiovascular Disease Patients in the Absence of a Baseline Stress Test

Aerobic exercise is a core component of cardiac rehabilitation (CR). Leading organizations recommend that the exercise prescriptions should be based on a symptom limited baseline graded exercise test (GXT). However, recent evidence suggests that only ~30% of CR clinics perform baseline GXTs. Consequently, exercise prescriptions including exercise progression in CR are not following standard exercise prescription guidelines. Therefore, the purpose of this review is to provide clinicians with evidence-based techniques for prescribing exercise in the absence of a baseline GXT. Intensity indicators (e.g., heart rate, perceived exertion) are reviewed, along with special exercise considerations for various disease states (e.g., heart failure, peripheral artery disease, and coronary artery disease). Baseline exercise testing remains the gold standard approach for prescribing exercise among heart disease patients, however, clinicians must be prepared to safely develop and monitor patients when a baseline GXT is not performed.