[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.

Prognostic Value of Peak Oxygen Uptake in Patients Supported With Left Ventricular Assist Devices (PRO-VAD)

OBJECTIVES

The purpose of this study was to examine whether peak oxygen uptake (pVO₂) and other cardiopulmonary exercise test (CPET)-derived variables could predict intermediate-term mortality in stable continuous flow LVAD recipients.

BACKGROUND

pVO₂ is a cornerstone in the selection of patients for heart transplantation, but the prognostic power of pVO₂ obtained in patients treated with a left ventricular assist device (LVAD) is unknown.

METHODS

We collected data for pVO₂ and outcomes in adult LVAD recipients in a retrospective, multicenter study and evaluated cutoff values for pVO₂ including: 1) values above or below medians; 2) grouping patients in tertiles; and 3) pVO₂ ≤14 ml/kg/min if the patient was not treated with beta-blockers (BB) or pVO₂ ≤12 ml/kg/min if the patient was taking BB therapy.

RESULTS

Nine centers contributed data from 450 patients. Patients were 53 ± 13 years of age; 78% were male; body mass index was 25 ± 5 kg/m² with few comorbidities (stroke: 11%; diabetes: 18%; and peripheral artery disease: 4%). The cause of heart failure (HF) was most often nonischemic (66%). Devices included were the HeartMate II and 3 (Abbott); and Heartware ventricular assist devices Jarvik and Duraheart (Medtronic). The index CPET was performed at a median of 189 days (154 days-225 days) after LVAD implantation, and mean pVO₂ was 14.1 ± 5 ml/kg/min (47% ± 14% of predicted value). Lower pVO₂ values were strongly associated with poorer survival regardless of whether patients were analyzed for absolute pVO₂ in ml/kg/min, pVO₂ ≤12 BB/14 ml/kg/min, or as a percentage of predicted pVO₂ values (P ≤ 0.001 for all). For patients with pVO₂ >12 BB/14 and ventilation/carbon dioxide relationship (VE/VCO₂) slope <35, the 1-year survival was 100%.

CONCLUSIONS

Even after LVAD implantation, pVO₂ has prognostic value, similar to HF patients not supported by mechanical circulatory support devices. (PROgnostic Value of Exercise Capacity Measured as Peak Oxygen Uptake [pVO₂] in Recipients of Left Ventricular Assist Devices [PRO-VAD]; NCT04423562).

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.

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.

Exercise after Heart Transplantation: Typical Alterations, Diagnostics and Interventions

For the treatment of terminal heart failure, heart transplantation is considered to be the gold standard, leading to significantly improved quality of life and long-time survival. For heart transplant recipients, the development and maintenance of good functional performance and adequate exercise capacity is crucial for renewed participation and integration in self-determined live. In this respect, typical transplant-related alterations must be noted that play a significant role, leading to restrictions both centrally and peripherally. Before patients begin intensive and structured exercise training, a comprehensive diagnosis of their exercise capacity should take place in order to stratify the risks involved and to plan the training units accordingly. Particularly endurance sports and resistance exercises are recommended to counter the effects of the underlying disease and the immunosuppressive medication. The performance level achieved can vary considerably depending on their individual condition, from gentle activity through a non-competitive-level to intensive competitive sports. This paper includes an overview of the current literature on heart transplant recipients, their specific characteristics, as well as typical cardiovascular and musculoskeletal alterations. It also discusses suitable tools for measuring exercise capacity, recommendations for exercise training, required precautions and the performance level usually achieved.

Inpatient Cardiac Rehabilitation of LVAD Patients-Updated Recommendations from the Working Group of the German Society for Prevention and Rehabilitation of Cardiovascular Diseases

Cardiac rehabilitation physicians are faced to an increasing number of heart failure patients supported by left ventricular assist devices (LVAD). Many of these patients have complex medical issues and prolonged hospitalizations and therefore need special cardiac rehabilitation strategies including psychological, social, and educational support which are actually poorly implemented.Cardiac rehabilitation with clear guidance and more evidence should be considered as an essential component of the patient care plan especially regarding the increasing number of destination patients and their long-term follow-up.In this article the working group for postimplant treatment and rehabilitation of LVAD patients of the German Society for Prevention and Rehabilitation of Cardiovascular Diseases has summarized and updated the recommendations for the cardiac rehabilitation of LVAD patients considering the latest literature.