Exercise Performance During the First Two Years After Left Ventricular Assist Device Implantation

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.

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.

Update on obesity, the obesity paradox, and obesity management in heart failure

Obesity is a major public health challenge worldwide. It is costly, predisposes to many cardiovascular (CV) diseases (CVD), is increasing at an alarming rate, and disproportionately affects people of low-socioeconomic status. It has a myriad of deleterious effects on the body, particularly on the CV system. Obesity is a major risk factor for heart failure (HF) and highly prevalent in this population, particularly in those with HF with preserved ejection fraction (HFpEF), to the extent that an obesity HFpEF phenotype has been proposed in the literature. However, once HF is developed, an obesity paradox exists where those with obesity have better short- and mid-term survival than normal or underweight individuals, despite a greater risk for hospitalizations. It may be argued that excess energy reserve, younger patient population, higher tolerability of HF therapy and better nutritional status may account for at least part of the obesity paradox on survival. Furthermore, body mass index (BMI) may not be an accurate measure of body composition, especially in HF, where there is an excess volume status. BMI also fails to delineate fat-free mass and its components, which is a better predictor of functional capacity and cardiorespiratory fitness (CRF), which particularly is increasingly being recognized as a risk modifier in both healthy individuals and in persons with comorbidities, particularly in HF. Notably, when CRF is accounted for, the obesity paradox disappears, suggesting that improving CRF might represent a therapeutic target with greater importance than changes in body weight in the setting of HF. In this narrative review, we discuss the current trends in obesity, the causal link between obesity and HF, an update on the obesity paradox, and a description of the major flaws of BMI in this population. We also present an overview of the latest in HF therapy, weight loss, CRF, and the application of these therapeutic approaches in patients with HF and concomitant obesity.

Exercise Performance and Quality of Life of Left Ventricular Assist Device Patients After Long-Term Outpatient Cardiac Rehabilitation

PURPOSE

Exercise performance and quality of life (QoL) of left ventricular assist device (LVAD) patients improve after early cardiac rehabilitation (CR). The purpose of this study was to examine the efficacy of multiprofessional long term phase 3 outpatient CR, and whether cardiopulmonary exercise testing (CPX) and 6-min walk testing (6MWT) post-LVAD implantation predict hospital readmission.

METHODS

This retrospective observational cohort study included 29 LVAD patients (58.6 ± 7.7 yr, female: 13.8%, body mass index: 29.4 ± 3.3 kg/m 2 ). Functional performance tests (CPX, 6MWT, sit-to-stand test), QoL, and psychological surveys (Kansas City Cardiomyopathy Questionnaire, hospital anxiety and depression scale, and Control Convictions about Disease and Health [KKG]) were performed at baseline and at the end of CR.

RESULTS

The CR was initiated at a median (IQR) of 159 (130-260) d after LVAD implantation for a duration of 340 (180-363) d with 46.8 ± 23.2 trainings. The 6MWT (408.4 ± 113.3 vs 455.4 ± 115.5 m, P = .003) and sit-to-stand test (16.7 ± 6.9 vs 19.0 ± 5.3 repetitions, P = .033) improved, but relative peak oxygen uptake (V˙ o2peak : 9.4 [8.2-14.4] vs 9.3 [7.8-13.4] mL/min/kg, P = .57) did not change. Using receiver operating characteristic curve analysis, baseline V˙ o2peak values were associated with readmission 1-yr after CR onset (C-statistic = 0.88) with a cutoff value of V˙ o2peak < 9.15 mL/min/kg (100% sensitivity, 78% specificity, P < .001). The Kansas City Cardiomyopathy Questionnaire self-efficacy and knowledge (+6.3 points), QoL (+5.0 points), and social limitation (+7.1 points) demonstrated clinically important changes. In addition, the hospital anxiety and depression scale showed a significant reduction in anxiety (4.6 ± 3.2 vs 2.6 ± 2.4, P = .03).

CONCLUSIONS

Long-term CR is safe and LVAD outpatients showed improvement of QoL, anxiety, and submaximal exercise performance. In addition, V˙ o2peak and 6MWT have prognostic value for readmission.

Impact of Mechanical Circulatory Support on Exercise Capacity in Patients With Advanced Heart Failure

Approximately 6 million individuals have heart failure in the United States alone and 15 million in Europe. Left ventricular assist devices (LVAD) improve survival in these patients, but functional capacity may not fully improve. This article examines the hypothesis that patients supported by LVAD experience persistent reductions in functional capacity and explores mechanisms accounting for abnormalities in exercise tolerance.

Exercise in patients with left ventricular devices: The interaction between the device and the patient

Advances in the engineering of surgically implanted, durable left ventricular assist devices (LVAD) has led to improvements in the two-year survival of patients on LVAD support, which is now comparable to that of heart transplant (HT) recipients. And with the advent of magnetic levitation technology, both the survival rate and average time on LVAD support are expected to improve even further. However, despite these advances, the functional capacity of patients on LVAD support remains reduced compared to those who received a HT. A few small clinical trials have shown improvement in functional capacity with exercise training. Peak oxygen uptake improves modestly (10%-20%) with exercise training, suggesting a possible celling-effect linked to the ability of the LVAD to increase flow during exercise. This paper reviews both (a) the effect of the LVAD on the cardiorespiratory responses during a single, acute bout of exercise up to maximum and (b) the central and peripheral adaptations that occur among patients with an LVAD who undergo an exercise training regimen. We also address the tenets of the exercise prescription that are unique to patients with a durable LVAD.

Variation in Cardiac Rehabilitation for Pediatric Ventricular Assist Device Recipients Across North America

Despite increasing utilization of continuous-flow pediatric ventricular assist devices (VAD) in children, data on exercise testing and cardiac rehabilitation (CR) are unknown. We described variation in CR practices and identified barriers to exercise testing and CR. A survey was performed through the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) representing pediatric VAD centers across North America. Descriptive statistics were performed. A multidisciplinary cohort of 52 respondents from 28 pediatric VAD centers responded. Although 38% reported performing exercise testing, most (65%) used 6 minute walk tests rather than formal cycle or treadmill exercise testing. While all respondents refer to physical therapy during the initial inpatient stay for VAD placement, only 52% refer to a CR program. When performed, CR was performed at an ACTION center (84%), a local specialized center (21%), or a home-based CR program (26%). Commonly cited barriers to either CR or exercise testing were inadequate resources, inadequate implementation logistics knowledge, concerns about safety, inability of patients to travel to a CR facility, and concern about utility of exercise testing or CR. Over 90% of centers were interested in implementing a standardized pediatric VAD CR program. Utilization of exercise testing and CR after VAD placement is variable. Despite perceived barriers, most pediatric VAD centers are interested in implementing a standardized CR program for recipients. In response to this interest, we plan to implement a standardized CR protocol to all ACTION pediatric VAD centers in an effort to improve pretransplant waitlist rehabilitation and post-transplant outcomes.

Impact of symptom-guided, progressive cardiac rehabilitation after left ventricular assist device implantation

A 29-year-old woman with a left ventricular assist device (LVAD) completed a progressive, symptom-limited cardiac rehabilitation program consisting of boxing, weight-lifting, and aerobic exercise, where she improved her exercise capacity by 2.7 metabolic equivalents (P < 0.001) and demonstrated significant myocardial recovery, allowing for successful LVAD explant 9 months after implantation.

Five-year outcomes of patients supported with HeartMate 3: a single-centre experience

OBJECTIVES

The HeartMate 3 left ventricular assist device was first implanted in 2014 and received the Conformité Européenne mark in 2015. Since then, several trials demonstrated its high haemocompatibility associated with good survival and low adverse events rates. Herein, we report our institutional experience with patients supported with HeartMate 3 for 5 years.

METHODS

This prospective cohort study included patients receiving a HeartMate 3 implantation in 2014 as part of the HeartMate 3 Conformité Européenne Mark clinical trial. Patients had follow-up visits every 3 months while on left ventricular assist device support, and all patients completed the 5-year follow-up. The primary end point was survival at 5 years. Secondary end points included adverse events, health status and quality of life.

RESULTS

Eight patients (men: 75%) aged 59 years (min-max: 52-66 years) were enrolled. At 5 years, survival was 100%. Patients remained on support for a median time of 1825 days (min-max: 101-1825 days); 2 patients successfully received cardiac transplants. No right heart failure, haemolysis, pump thrombosis, pump malfunction or neurological events occurred in any patients. A driveline infection was observed in 6 patients (0.25 events/patient-year). Compared to baseline, a significant improvement in quality of life and in New York Heart Association functional class was noted after the implant and for the whole follow-up time. A slight decline in kidney function and in the 6-min walk test results occurred after 3 years.

CONCLUSIONS

This study reports the longest single-centre follow-up of the HeartMate 3, showing excellent haemocompatibility over time with high survival and low complication rates at 5 years.

Exercise physiology in left ventricular assist device patients: insights from hemodynamic simulations

Left ventricular assist devices (LVADs) assure longer survival to patients, but exercise capacity is limited compared to normal values. Overall, LVAD patients show high wedge pressure and low cardiac output during maximal exercise, a phenomenon hinting at the need for increased LVAD support. Clinical studies investigating the hemodynamic benefits of an LVAD speed increase during exercise, ended in inhomogeneous and sometimes contradictory results. The native ventricle-LVAD interaction changes between rest and exercise, and this evolution is complex, multifactorial and patient-specific. The aim of this paper is to provide a comprehensive overview on the patient-LVAD interaction during exercise and to delineate possible therapeutic strategies for the future. A computational cardiorespiratory model was used to simulate the hemodynamics of peak bicycle exercise in LVAD patients. The simulator included the main cardiovascular and respiratory impairments commonly observed in LVAD patients, so as to represent an average hemodynamic response to exercise. In addition, other exercise responses were simulated, by tuning the chronotropic, inotropic and vascular functions, and implementing aortic regurgitation and stenosis in the simulator. These profiles were tested under different LVAD speeds and LVAD pressure-flow characteristics. Simulations output showed consistency with clinical data from the literature. The simulator allowed the working condition of the assisted ventricle at exercise to be investigated, clarifying the reasons behind the high wedge pressure and poor cardiac output observed in the clinics. Patients with poorer inotropic, chronotropic and vascular functions, are likely to benefit more from an LVAD speed increase during exercise. Similarly, for these patients, a flatter LVAD pressure-flow characteristic can assure better hemodynamic support under physical exertion. Overall, the study evidenced the need for a patient-specific approach on supporting exercise hemodynamics. In this frame, a complex simulator can constitute a valuable tool to define and test personalized speed control algorithms and strategies.

Determinants of Functional Capacity and Quality of Life After Implantation of a Durable Left Ventricular Assist Device

Continuous-flow left ventricular assist devices (LVAD) are increasingly used as destination therapy in patients with end-stage heart failure and, with recent improvements in pump design, adverse event rates are decreasing. Implanted patients experience improved survival, quality of life (QoL) and functional capacity (FC). However, improvement in FC and QoL after implantation is not unequivocal, and this has implications for patient selection and preimplantation discussions with patients and relatives. This article identifies preimplantation predictors of lack of improvement in FC and QoL after continuous-flow LVAD implantation and discusses potential mechanisms, allowing for the identification of potential factors that can be modified. In particular, the pathophysiology behind insufficient improvement in peak oxygen uptake is discussed. Data are included from 40 studies, resulting in analysis of >700 exercise tests. Mean peak oxygen uptake was 13.4 ml/kg/min (equivalent to 48% of predicted value; 259 days after implantation, range 31–1,017 days) and mean 6-minute walk test distance was 370 m (182 days after implantation, range 43–543 days). Finally, the interplay between improvement in FC and QoL is discussed.

2019 EACTS Expert Consensus on long-term mechanical circulatory support

Long-term mechanical circulatory support (LT-MCS) is an important treatment modality for patients with severe heart failure. Different devices are available, and many-sometimes contradictory-observations regarding patient selection, surgical techniques, perioperative management and follow-up have been published. With the growing expertise in this field, the European Association for Cardio-Thoracic Surgery (EACTS) recognized a need for a structured multidisciplinary consensus about the approach to patients with LT-MCS. However, the evidence published so far is insufficient to allow for generation of meaningful guidelines complying with EACTS requirements. Instead, the EACTS presents an expert opinion in the LT-MCS field. This expert opinion addresses patient evaluation and preoperative optimization as well as management of cardiac and non-cardiac comorbidities. Further, extensive operative implantation techniques are summarized and evaluated by leading experts, depending on both patient characteristics and device selection. The faculty recognized that postoperative management is multidisciplinary and includes aspects of intensive care unit stay, rehabilitation, ambulatory care, myocardial recovery and end-of-life care and mirrored this fact in this paper. Additionally, the opinions of experts on diagnosis and management of adverse events including bleeding, cerebrovascular accidents and device malfunction are presented. In this expert consensus, the evidence for the complete management from patient selection to end-of-life care is carefully reviewed with the aim of guiding clinicians in optimizing management of patients considered for or supported by an LT-MCS device.

Development of exercise-related values in heart failure patients supported with a left ventricular assist device

Following implantation of a left ventricular assist device, the build-up and long-term maintenance of adequate exercise capacity and functional performance become crucial. The aim of this study was to observe the development of exercise-related values at different times, as well as to detect possible influencing factors. We performed a prospective single-centre study: 10 patients (63 years, 100% male, body mass index = 27.5, 100% HeartWare) underwent the following diagnostic tests during cardiac rehabilitation and during two subsequent ambulatory visits: 6-min walking test, handgrip strength test, cardiopulmonary exercise test and Minnesota Living with Heart Failure questionnaire. Mean follow-up was 482 days after left ventricular assist device implantation. Significant improvements could be observed between the end of cardiac rehabilitation and ambulatory visit 1; 6-min walking distance increased from 367 to 449 m (p < 0.01), peak VO2 from 10.0 to 11.9 mL/kg/min (p < 0.05) and peak load from 62.4 to 83.0 W (p < 0.01). However, there were no further improvements between ambulatory visit 1 and ambulatory visit 2. In the long term, a significant mean weight gain of more than 10 kg could be observed (p < 0.01). A negative linear correlation between weight gain and absolute improvement in peak load (r = −0.77, p < 0.01) and peak VO2 (r = −0.75, p < 0.05) could be demonstrated. In conclusion, exercise-related values following left ventricular assist device implantation initially improve significantly. Later, however, no further improvements can be observed. In the long term, pronounced weight gain is conspicuous, concomitant with a significantly lower increase in exercise values of the patients. In the future, both dietary and structured physical activity follow-up interventions should be integrated in patient routines.

LVAD Pump Flow Does Not Adequately Increase With Exercise

Left ventricular assist devices (LVADs) restore cardiovascular circulatory demand at rest with a spontaneous increase in pump flow to exercise. The relevant contribution of cardiac output provided by the LVAD and ejected through the aortic valve for exercises of different intensities has been barely investigated in patients. The hypothesis of this study was that different responses in continuous recorded pump parameters occur for maximal and submaximal intensity exercises and that the pump flow change has an impact on the oxygen uptake at peak exercise (pVO₂ ). Cardiac and pump parameters such as LVAD flow rate (Q_LVAD ), heart rate (HR), and aortic valve (AV) opening were analyzed from continuously recorded LVAD data during physical exercises of maximal (bicycle ergometer test) and submaximal intensities (6-min walk test and regular trainings). During all exercise sessions, the LVAD speed was kept constant. Cardiac and pump parameter responses of 16 patients for maximal and submaximal intensity exercises were similar for Q_LVAD : +0.89 ± 0.52 versus +0.59 ± 0.38 L/min (P = 0.07) and different for HR: +20.4 ± 15.4 versus +7.7 ± 5.8 bpm (P < 0.0001) and AV-opening with 71% versus 23% of patients (P < 0.0001). Multi-regression analysis with pVO₂ (R²  = 0.77) showed relation to workload normalized by bodyweight (P = 0.0002), HR response (P = 0.001), AV-opening (P = 0.02), and age (P = 0.06) whereas the change in Q_LVAD was irrelevant. Constant speed LVADs provide inadequate support for maximum intensity exercises. AV-opening and improvements in HR show an important role for higher exercise capacities and reflect exercise intensities. Changes in pump flow do not impact pVO₂ and are independent of AV-opening and response in HR. An LVAD speed control may lead to adequate left ventricular support during strenuous physical activities.