High-intensity interval training in patients with left ventricular assist devices: A pilot randomized controlled trial

Obesity, Challenges, and Weight-Loss Strategies for Patients With Ventricular Assist Devices

For adults with advanced heart failure, class II/III obesity (body mass index ≥35 kg/m2) represents major challenges, and it is even considered a contraindication for heart transplantation (HT) at many centers. This has led to growing interest in preventing and treating obesity to help patients with advanced heart failure become HT candidates. Among all weight-loss strategies, bariatric surgery (BSx) has the greatest weight loss efficacy and has shown value in enabling select patients with left ventricular assist devices (LVADs) and obesity to lose sufficient weight to access HT. Nevertheless, both BSx and antiobesity medications warrant caution in the LVAD population. In this review, the authors describe and interpret the available published reports on the impact of obesity and weight-loss strategies for patients with LVADs from general and HT candidacy standpoints. The authors also provide an overview of the journey of LVAD recipients who undergo BSx and review major aspects of perioperative protocols.

Exercise and weight loss with a left ventricular assist device: A case report and review of the literature

With changes in the heart transplant allocation system in the United States, the use of left ventricular device therapy (LVAD) as a bridge to transplant has decreased. Currently, one of the primary reasons to implant a device is for patient support until they can lose weight to qualify for transplant. This paper reviews the outcomes of various weight loss strategies for patients with LVADs including weight reduction surgery and cardiac rehab. Additionally, results of the use of GLP1 agonists on weight loss in general and in heart failure patients is reviewed. Finally, because of the unique issues involving exercise for patients with LVADs, we review safe exercise techniques with instructions for patients.

Effects of cardiac rehabilitation in patients with ventricular assist devices: a scoping review

INTRODUCTION

Ventricular assist devices represent a treatment option for patients with advanced heart failure, offering control over various haemodynamic variables. Similarly, the prescription of exercise within a cardiac rehabilitation programme for heart failure patients is recommended to reduce symptoms, and hospitalisations, improve cardiorespiratory fitness, and increase exercise tolerance. Therefore, exercise prescription can impact those with ventricular assist devices. Given the limited evidence on exercise-based cardiac rehabilitation programmes for this population, this review aims to describe the most commonly used strategies and their health benefits when physical exercise is included in a cardiac rehabilitation programme for patients with ventricular assist devices.

MATERIALS AND METHODS

An exploratory review was conducted through searches in the databases: PubMed, SCOPUS, PeDro, and ScienceDirect. The search was limited to studies published between 2013 and 2023. Filters were applied independently by title, abstract, and full text. The included articles were analysed based on the description of the types of cardiac rehabilitation strategies used in patients with ventricular assist devices.

RESULTS

Seven articles were included. Each programme employed a cardiopulmonary exercise test before prescribing physical exercise. The most commonly used strategy was aerobic exercise, predominantly high-intensity interval training (HIIT) with intensities close to 90% of peak VO2, followed by continuous moderate-intensity exercise. Limb strength exercises were included in three programmes.

CONCLUSIONS

The analysed literature suggests that cardiac rehabilitation in patients with ventricular assist devices is safe and can provide benefits in cardiorespiratory fitness and exercise tolerance. High-intensity interval training is identified as an appropriate strategy for achieving results, offering short-term improvements.

The Impact of Acute Exercise on Hemostasis and Angiogenesis Mediators in Patients With Continuous-Flow Left Ventricular Assist Devices: A Prospective Observational Pilot Study

Impaired primary hemostasis and dysregulated angiogenesis, known as a two-hit hypothesis, are associated with gastrointestinal (GI) bleeding in patients with continuous-flow left ventricular assist devices (CF-LVADs). Exercise is known to influence hemostasis and angiogenesis in healthy individuals; however, little is known about the effect in patients with CF-LVADs. The objective of this prospective observational study was to determine whether acute exercise modulates two-hit hypothesis mediators associated with GI bleeding in patients with a CF-LVAD. Twenty-two patients with CF-LVADs performed acute exercise either on a cycle ergometer for approximately 10 minutes or on a treadmill for 30 minutes. Blood samples were taken pre- and post-exercise to analyze hemostatic and angiogenic biomarkers. Acute exercise resulted in an increased platelet count (p < 0.00001) and platelet function (induced by adenosine diphosphate, p = 0.0087; TRAP-6, p = 0.0005; ristocetin, p = 0.0009). Additionally, high-molecular-weight vWF multimers (p < 0.00001), vWF collagen-binding activity (p = 0.0012), factor VIII (p = 0.034), angiopoietin-1 (p = 0.0026), and vascular endothelial growth factor (p = 0.0041) all increased after acute exercise. This pilot work demonstrates that acute exercise modulated two-hit hypothesis mediators associated with GI bleeding in patients with CF-LVADs.

Effectiveness of exercise-based cardiac rehabilitation for patients with left ventricular assist device: A systematic review and meta-analysis

PURPOSE

Exercise-based cardiac rehabilitation (EBCR) improves functional capacity in heart failure (HF). However, data on the effect of EBCR in patients with advanced HF and left ventricular assist devices (LVADs) are limited. This meta-analysis aimed to evaluate the impact of EBCR on the functional ability of LVAD patients by comparing the corresponding outcome indicators between the EBCR and ST groups.

METHODS

PubMed, Embase, Clinical Trials, and Cochrane Library databases were searched for studies assessing and comparing the effects of EBCR and standard therapy (ST) in patients following LVAD implantation. Using pre-defined criteria, appropriate studies were identified and selected. Data from selected studies were extracted in a standardized fashion, and a meta-analysis was performed using a fixed-effects model. The protocol was registered on INPLASY (202340073).

RESULTS

In total, 12 trials involving 477 patients were identified. The mean age of the participants was 52.9 years, and 78.6% were male. The initiation of EBCR varied from LVAD implantation during the index hospitalization to 11 months post-LVAD implantation. The median rehabilitation period ranged from 2 weeks to 18 months. EBCR was associated with improved peak oxygen uptake (VO2) in all trials. Quantitative analysis was performed in six randomized studies involving 214 patients (EBCR: n = 130, ST: n = 84). EBCR was associated with a significantly high peak VO2 (weighted mean difference [WMD] = 1.64 mL/kg/min; 95% confidence interval [CI], 0.20-3.08; p = .03). Similarly, 6-min walk distance (6MWD) showed significantly greater improvement in the EBCR group than in the ST group (WMD = 34.54 m; 95% CI, 12.47-56.42; p = .002) in 266 patients (EBCR, n = 140; ST, n = 126). Heterogeneity was low among the included trials. None of the included studies reported serious adverse events related to EBCR, indicating the safety of EBCR after LVAD implantation.

CONCLUSION

This study demonstrated that EBCR following LVAD implantation is associated with greater improvement in functional capacity compared with ST as reflected by the improved peak VO2 and 6MWD values. Considering the small number of patients in this analysis, further research on the clinical impact of EBCR in LVAD patients is warranted.

Exercise, cancer, and the cardiovascular system: clinical effects and mechanistic insights

Cardiovascular diseases and cancer are the leading causes of death in the Western world and share common risk factors. Reduced cardiorespiratory fitness (CRF) is a major determinant of cardiovascular morbidity and cancer survival. In this review we discuss cancer- induced disturbances of parenchymal, cellular, and mitochondrial function, which limit CRF and may be antagonized and attenuated through exercise training. We show the impact of CRF on cancer survival and its attenuating effects on cardiotoxicity of cancer-related treatment. Tailored exercise programs are not yet available for each tumor entity as several trials were performed in heterogeneous populations without adequate cardiopulmonary exercise testing (CPET) prior to exercise prescription and with a wide variation of exercise modalities. There is emerging evidence that exercise may be a crucial pillar in cancer treatment and a tool to mitigate cardiotoxic treatment effects. We discuss modalities of aerobic exercise and resistance training and their potential to improve CRF in cancer patients and provide an example of a periodization model for exercise training in cancer.

Supervised exercise training in patients with advanced heart failure and left ventricular assist device: A multicentre randomized controlled trial (Ex-VAD trial)

AIMS

Small studies and observations suggested that exercise training may improve peak oxygen consumption (peakVO2 ) in patients with advanced heart failure and left ventricular assist device (LVAD). We investigated whether in this patient group a supervised exercise training can improve exercise capacity.

METHODS AND RESULTS

In this multicentre, prospective, randomized, controlled trial, patients with stable heart failure and LVAD were randomly assigned (2:1) to 12 weeks of supervised exercise training or usual care, with 12 weeks of follow-up. The primary endpoint was the change in peakVO2 after 12 weeks (51 patients provided a power of 90% with an expected group difference in peakVO2 of 3 ml/kg/min). Secondary endpoints included changes in submaximal exercise capacity and quality of life. Among 64 patients enrolled (97% male, mean age 56 years), 54 were included in the analysis. Mean difference in the change of peakVO2 after 12 weeks was 0.826 ml/min/kg (95% confidence interval [CI] -0.37, 2.03; p = 0.183). There was a positive effect of exercise training on 6-min walk distance with a mean increase in the intervention group by 43.4 m (95% CI 16.9, 69.9; p = 0.0024), and on the Kansas City Cardiomyopathy Questionnaire physical domain score (mean 14.3, 95% CI 3.7, 24.9; p = 0.0124), both after 12 weeks. The overall adherence was high (71%), and there were no differences in adverse events between groups.

CONCLUSION

In patients with advanced heart failure and LVAD, 12 weeks of exercise training did not improve peakVO2 but demonstrated positive effects on submaximal exercise capacity and physical quality of life.

[Cardiac rehabilitation in LVAD patients : Aspects regarding exercise and rhythm]

After implantation of a left ventricular assist device (LVAD), it is strongly recommended that patients participate in an inpatient cardiac rehabilitation program (CR). Relevant topics during CR include sports and exercise therapy as well as aspects of cardiac rhythm control. Over time, LVAD patients usually regain a good quality of life and an adequate functional capacity can be observed. However, maximum performance values remain markedly reduced, in part due to the fixed LVAD pump speed and the limited total cardiac output. Therefore, structured long-term exercise training programs (even beyond CR phase II) are of particular importance in order to optimize neuromuscular control and muscle metabolism. Limitations to physical performance values may also be caused by the occurrence of supraventricular and/or ventricular arrhythmias. In both cases, the cause is an increasing hemodynamic impairment of the right heart, which may also lead to a reduced LVAD pump flow. In addition, inadequate setting of other cardiac implantable electronic devices (e.g., implantable cardioverter-defibrillator [ICD] or cardiac resynchronization therapy with defibrillator [CRT-D]) may also have a crucial impact on hemodynamics after LVAD implantation. In this article, we will discuss specific aspects of LVAD therapy related to exercise and rhythm control, particularly in the context of CR programs.

Moderate Continuous and Modified High-Intensity Interval Training in Patients With Left Ventricular Assist Devices: The Prospective Train-the-LVAD Trial

BACKGROUND

High-intensity interval training (HIIT) of 4 minutes at 80%-90% of peak oxygen consumption (VO_2peak) has been shown to be feasible in patients with left ventricular assist devices (LVADs). The effect of shorter bouts of HIIT, which reduce the anaerobic burden, has not been investigated compared to moderate continuous training (MCT).

METHODS AND RESULTS

We conducted a prospective, monocentric study (NCT05121077) randomizing patients with LVADs into 20 minutes of MCT (n = 10) or short bouts (≤ 90 seconds) of HIIT (n = 10) following cardiopulmonary exercise testing at 50%-60% and 80%-90% of VO_2peak. Each of the 18 supervised sessions (3×/week, t_0-t₁) included 10 minutes of strengthening training. The primary outcome was the increase of VO_2peak in the 2 groups between t₀ and t₁. Secondary outcomes were changes in the 12-item Kansas City Cardiomyopathy Questionnaire, the 6-minute walk distance and the percentage of VO_2peak at the first ventilatory threshold. VO_2peak significantly increased with HIIT (13.0 ± 4.6mL/kg/min vs 14.6 ± 4.3mL/kg/min; P = 0.037), but not with MCT (11.8 ± 3.3mL/kg/min vs 13.1 ± 3.3mL/kg/min; P = 0.322), without between-group differences (P = 0.853). Secondary outcomes improved from t_0-t₁ in MCT and HIIT, without differences between the groups.

CONCLUSIONS

Short bouts of HIIT are feasible, and they improved VO_2peak and functional parameters in patients in this pilot prospective study.

Exercise oscillatory ventilation in patients with advanced heart failure with and without left ventricular assist device

BACKGROUND

Exercise oscillatory ventilation (EOV), indicating pathological fluctuations on pulmonary arterial pressure, is associated with mortality in patients with heart failure (HF). Whether left ventricular assist device (LVAD)-induced ventricular unloading can reverse EOV and may prevent short-term rehospitalization has not been investigated.

METHODS

We performed a retrospective single-center in- and outpatient analysis of patients with (n = 20, LVAD) and without (n = 27, HF) circulatory support and reduced ejection fraction (EF, 22.8 ± 7.9%). The association of cardiopulmonary exercise testing (CPET) variables and 3 months-rehospitalization (3MR) as a primary outcome was analyzed. Furthermore, CPET variables were compared regarding the presence of EOV (+/-).

RESULTS

Lower VO_2peak (11.6 ± 4.9 ml/kg/min vs. 14.4 ± 4.3 ml/kg/min, p = 0.039), lower increase of PETCO₂ (CI = 0.049-1.127; p = 0.068), and higher VE/VCO₂ (43.8 ± 9.5 vs. 38.3 ± 10.6; p = 0.069) were associated with 3MR. Flattening of O₂ pulse (CI = 0.139-2.379; p = 0.487) had no impact on 3MR. EOV was present in 59.5% (n = 28/47) of patients, without a significant difference between LVAD and HF patients (p = 0.959). Patients with HF/EOV+ demonstrated significantly lower VO_2peak compared with HF/EOV- (p = 0.039). LVAD/EOV+ displayed significantly lower EF (p = 0.004) and fewer aortic valve opening than LVAD/EOV- (p = 0.027).

CONCLUSIONS

Lower VO_2peak , but not EOV, was associated with 3MR. EOV occurred at a similar rate in LVAD and HF patients, which may illustrate insufficient unloading during exercise in chronic LVAD therapy and may contribute to the limited exercise capacity following LVAD implantation. Simultaneous CPET and right heart catheterization studies are needed to elucidate whether EOV may serve as a non-invasive predictor of insufficient LV unloading necessitating LVAD reprograming.

Exercise training in cardiac rehabilitation: Setting the right intensity for optimal benefit

Cardiac rehabilitation (CR) programs are recommended standard-of-care by all major cardiovascular medicine professional organizations. Exercise training is the cornerstone for CR, with aerobic training being the primary form of training. The benefits of exercise training are multiple; however, improved cardiorespiratory fitness is of utmost importance. Moderate-intensity continuous training, supplemented with resistance training, has traditionally been the most common form of exercise training in CR. This review discusses the role of aerobic exercise training in CR and the importance of effective and personalized exercise prescription for optimized results. We also focus on the benefits and utility of high-intensity interval training across different clinical populations commonly seen in the CR setting.

Effect of Exercise Prescription Implementation Rate on Cardiovascular Events

BACKGROUND

Exercise prescription of cardiac rehabilitation (CR) is vital in patients with cardiovascular diseases (CVDs) and those carrying high risk for CVDs. However, the relation between the implementation rate of exercise prescription and cardiovascular events (CVEs) is unclear.

DESIGN AND METHODS

In this retrospective study, using the administration data from the Rehabilitation Center in a hospital, patients aged ≥18 years with CVDs were consecutively enrolled from November 2018 to May 2021. Patients were divided into the high execution group (HEG) and low execution group (LEG) depending on whether they completed more than half the time of the exercise prescriptions. Baseline characteristics, ultrasonic cardiogram, cardiopulmonary exercise test, follow-up data, and CVEs were collected.

RESULTS

The mean age of the 197 CR patients was 61.8 ± 13.7 years and the mean follow-up duration was 10.9 ± 4.2 months. Among them, 15 patients suffered CVEs: 4 in the HEG and 11 in the LEG. The incidence of CVEs showed significant differences between HEG and LEG (chi-square test). Free-event survival analysis using Kaplan-Meier survival plots showed that patients in LEG had poor survival. Cox proportional hazards regression analysis revealed that the prescription implementation rate was an independent predictor of CVEs.

CONCLUSIONS

Our study suggested a significant effect of exercise prescription execution rate on the occurrence of CVEs. Further, the HEG of exercise prescription was associated with lower CVDs.

Efficacy and Safety of Different Aerobic Exercise Intensities in Patients With Heart Failure With Reduced Ejection Fraction: Design of a Multicenter Randomized Controlled Trial (HF-EI Trial)

Background: Heart failure (HF) is one of the major causes of mortality worldwide, representing the terminal stage of several cardiovascular diseases. Exercise-based rehabilitation is a beneficial therapy for patients with chronic heart failure (CHF). However, there is a lack of specific guidance on clinical decision-making regarding optimal exercise intensity. It is necessary to optimize the clinical recommendations for HF exercises. We will evaluate the efficacy and safety of different aerobic exercise intensities in patients with heart failure with reduced ejection fraction (HFrEF): the HF-EI trial. This trial aims to assess the appropriate exercise intensity for patients with HFrEF.

Methods: After a baseline assessment to determine the safety of exercise, 180 patients will be randomly assigned to supervised high-intensity exercise training (ET) group, supervised moderate intensity training (MIT) group, and control group at a ratio of 1:1:1. Patients randomly receiving high intensity training (HIT) undergo supervised ET (3 times/week, 30 min) for aerobic endurance at 70% peak oxygen consumption (peak VO₂) intensity for 12 weeks. The MIT patients will perform supervised aerobic ET (3 times/week, 35–42 min) at the anaerobic threshold (AT) intensity for 12 weeks. The control group will continue to maintain their daily activities and will not receive ET. During the baseline and follow-up period, physical examination, laboratory tests, cardiology diagnostic tests, cardiopulmonary exercise tests (CPET), 6-min walk distance (6MWD), scale scores, exercise steps, medications, and clinical events will be monitored. Throughout the research, sport bracelets and patient diaries will be used to monitor and record overall physical activity, training courses, and compliance.

Discussion: The HF-EI trial will evaluate the effects of different aerobic exercise intensities on peak VO₂, quality of life (QoL), and clinical events among patients with HFrEF. The findings of this trial will provide a basis for formulating exercise prescriptions for patients with HFrEF.

Clinical Trial Registration:http://www.chictr.org.cn/, identifier: ChiCTR2000036381.

The importance of physical activity and cardiorespiratory fitness for patients with heart failure

The present review highlights current research on the importance of PA and fitness for patients with heart failure and recommendations with respect to heart failure phenotypes and special populations. Furthermore, the evidence for various exercise types and intensities/doses as an "exercise prescription", are discussed. The strong association between heart failure and traditional risk factors, physical inactivity and low fitness, underlines the importance of regular PA and exercise for prevention and treatment of heart failure. This is illustrated by cardiac stiffness which typically accelerates in middle-life and could be reversed by aerobic exercise. In patients with HFpEF, regular PA counteracts many of the changes observed, both metabolic and functional. Indeed, exercise-based cardiac rehabilitation has received a class 1A recommendation in current guidelines [1], in order to improve functional capacity, quality of life and lower the risk of rehospitalization. An individually tailored plan based on risk stratification, clinical assessment and cardiopulmonary exercise testing is encouraged before initiation of exercise training in patients with heart failure. In general, a combination of aerobic exercise and resistance training protocols is recommended (Table 1) [2], preferably throughout life. More studies are needed, regarding the role of PA and exercise in specific populations, such as frail patients with heart failure.