Functional and haemodynamic recovery after implantation of continuous-flow left ventricular assist devices in comparison with pulsatile left ventricular assist devices in patients with end-stage heart failure

Standardised Exercise Prescription for Patients with Chronic Coronary Syndrome and/or Heart Failure: A Consensus Statement from the EXPERT Working Group

Whereas exercise training, as part of multidisciplinary rehabilitation, is a key component in the management of patients with chronic coronary syndrome (CCS) and/or congestive heart failure (CHF), physicians and exercise professionals disagree among themselves on the type and characteristics of the exercise to be prescribed to these patients, and the exercise prescriptions are not consistent with the international guidelines. This impacts the efficacy and quality of the intervention of rehabilitation. To overcome these barriers, a digital training and decision support system [i.e. EXercise Prescription in Everyday practice & Rehabilitative Training (EXPERT) tool], i.e. a stepwise aid to exercise prescription in patients with CCS and/or CHF, affected by concomitant risk factors and comorbidities, in the setting of multidisciplinary rehabilitation, was developed. The EXPERT working group members reviewed the literature and formulated exercise recommendations (exercise training intensity, frequency, volume, type, session and programme duration) and safety precautions for CCS and/or CHF (including heart transplantation). Also, highly prevalent comorbidities (e.g. peripheral arterial disease) or cardiac devices (e.g. pacemaker, implanted cardioverter defibrillator, left-ventricular assist device) were considered, as well as indications for the in-hospital phase (e.g. after coronary revascularisation or hospitalisation for CHF). The contributions of physical fitness, medications and adverse events during exercise testing were also considered. The EXPERT tool was developed on the basis of this evidence. In this paper, the exercise prescriptions for patients with CCS and/or CHF formulated for the EXPERT tool are presented. Finally, to demonstrate how the EXPERT tool proposes exercise prescriptions in patients with CCS and/or CHF with different combinations of CVD risk factors, three patient cases with solutions are presented.

Listing criteria for heart transplantation in the Netherlands

The updated listing criteria for heart transplantation are presented on behalf of the three heart transplant centres in the Netherlands. Given the shortage of donor hearts, selection of those patients who may expect to have the greatest benefit from a scarce societal resource in terms of life expectancy and quality of life is inevitable. The indication for heart transplantation includes end-stage heart disease not remediable by more conservative measures, accompanied by severe physical limitation while on optimal medical therapy, including ICD/CRT‑D. Assessment of this condition requires cardiopulmonary stress testing, prognostic stratification and invasive haemodynamic measurements. Timely referral to a tertiary centre is essential for an optimal outcome. Chronic mechanical circulatory support is being used more and more as an alternative to heart transplantation and to bridge the progressively longer waiting time for heart transplantation and, thus, has become an important treatment option for patients with advanced heart failure.

One year improvement of exercise capacity in patients with mechanical circulatory support as bridge to transplantation

AIMS

Mechanical circulatory support (MCS) results in substantial improvement of prognosis and functional capacity. Currently, duration of MCS as a bridge to transplantation (BTT) is often prolonged due to shortage of donor hearts. Because long-term results of exercise capacity after MCS are largely unknown, we studied serial cardiopulmonary exercise tests (CPETs) during the first year after MCS implantation.

METHODS AND RESULTS

Cardiopulmonary exercise tests at 6 and 12 months after MCS implantation in BTT patients were retrospectively analysed, including clinical factors related to exercise capacity. A total of 105 MCS patients (67% male, 50 ± 12 years) underwent serial CPET at 6 and 12 months after implantation. Power (105 ± 35 to 114 ± 40 W; P ≤ 0.001) and peak VO2 per kilogram (pVO2/kg) improved significantly (16.5 ± 5.0 to 17.2 ± 5.5 mL/kg/min (P = 0.008)). Improvement in pVO2 between 6 and 12 months after LVAD implantation was not related to heart failure aetiology or haemodynamic severity prior to MCS. We identified maximal heart rate at exercise as an important factor for pVO2. Younger age and lower BMI were related to further improvement. At 12 months, 25 (24%) patients had a normal exercise capacity (Weber classification A, pVO2 > 20 mL/kg/min).

CONCLUSIONS

Exercise capacity (power and pVO2) increased significantly between 6 and 12 months after MCS independent of Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile or heart failure aetiology. Heart rate at exercise importantly relates to exercise capacity. This long-term improvement in exercise capacity is important information for the growing group of long-term MCS patients as this is critical for the quality of life of patients.

The role of long-term mechanical circulatory support in patients with advanced heart failure

In patients with end-stage heart failure, advanced therapies such as heart transplantation and long-term mechanical circulatory support (MCS) with a left ventricular assist device (LVAD) have to be considered. LVADs can be implanted as a bridge to transplantation or as an alternative to heart transplantation: destination therapy. In the Netherlands, long-term LVAD therapy is gaining importance as a result of increased prevalence of heart failure together with a low number of heart transplantations due to shortage of donor hearts. As a result, the difference between bridge to transplantation and destination therapy is becoming more artificial since, at present, most patients initially implanted as bridge to transplantation end up receiving extended LVAD therapy. Following LVAD implantation, survival after 1, 2 and 3 years is 83%, 76% and 70%, respectively. Quality of life improves substantially despite important adverse events such as device-related infection, stroke, major bleeding and right heart failure. Early referral of potential candidates for long-term MCS is of utmost importance and positively influences outcome. In this review, an overview of the indications, contraindications, patient selection, clinical outcome and optimal time of referral for long-term MCS is given.

Weight evolution after implantation of left ventricular assist device: Do we need to interfere?

OBJECTIVES

Weight change after left ventricular assist device implantation may influence outcomes and can affect transplant candidacy. We questioned if there is a systematic weight change after left ventricular assist device implantation and examined the evolution in functional capacity.

METHODS

A retrospective analysis of 84 patients who received a left ventricular assist device in Universitaire Ziekenhuizen Leuven between 2008 and 2016 was performed. Patients were divided into four groups based on their baseline body mass index, and we also examined weight evolution for patients presenting with new-onset heart failure versus those suffering from chronic heart failure. Body mass index was assessed at baseline, 6, 12, 18, and 24 months. To indicate the functional capacity, we analyzed the results of routine 6-Minute Walk Test performed at 6, 12, and 18 months.

RESULTS

During the first 6 months after surgery, the underweight patients evolved to normal weight and the body mass index of the obese patients reduced significantly. Afterward, all patients gained weight. The weight loss of the obese was not maintained over time. The weight of patients with normal weight and overweight evolved to overweight and obesity, respectively. No body mass index changes were demonstrated for patients presenting with new-onset heart failure, and the body mass index of patients suffering from chronic HF significantly increased. There was a significant improvement in functional capacity at 6 months, but this level remained unchanged at 12 and 18 months after surgery.

CONCLUSION

Although the initial 6 months evolve beneficial, all patients gain weight in the second year and do not further improve their exercise capacity.

The role of exercise hemodynamics in assessing patients with chronic heart failure and left ventricular assist devices

Introduction: Chronic heart failure is characterized by reduced exercise capacity. Invasive exercise hemodynamics are not routinely performed unless patients undergo transplant or left ventricular assist devices (LVAD) assessment, though now with readily available noninvasive devices, exercise hemodynamics are easily obtained. Our contention is that this is a valuable opportunity to acquire a more accurate measure of cardiac status in heart failure. Exercise hemodynamic measures such as cardiac power output can be carried out cheaply and effectively. Recent studies have highlighted the added value of exercise hemodynamics in prognostication of heart failure, and their role in assessing myocardial recovery in LVADs. Areas covered: In this review, we explore the literature available on Medline until 2019 focusing on resting and exercise hemodynamics alongside the methods of assessment (invasive and noninvasive) in heart failure with reduced ejection fraction and patients with implanted LVADs. Expert opinion: Hemodynamics measured both at rest and exercise are expected to play a significant role in the work up of transplant and LVAD patients. Furthermore, there is the potential to utilize noninvasive assessment in a complimentary fashion to support patient selection and improve the monitoring of response to treatment across the full cohort of heart failure patients.

Left ventricular assist device: exercise capacity evolution and rehabilitation added value

BACKGROUND

With more than 15,000 implanted patients worldwide and a survival rate of 80% at 1-year and 59% at 5-years, left ventricular assist device (LVAD) implantation has become an interesting strategy in the management of heart failure patients who are resistant to other kinds of treatment. There are limited data in the literature on the change over time of exercise capacity in LVAD patients, as well as limited knowledge about the beneficial effects that rehabilitation might have on these patients. Therefore, the aim of our study was to evaluate the evolution of exercise capacity on a cohort of patients implanted with the same device (HeartWare^©) and to analyse the potential impact of rehabilitation.

METHODS

Sixty-two patients implanted with a LVAD between June 2011 and June 2015 were screened. Exercise capacity was evaluated by cardiopulmonary exercise testing at 6 weeks, 6 and 12 months after implantation.

RESULTS

We have observed significant differences in the exercise capacity and evolution between the trained and non-trained patients. Some of the trained patients nearly normalised their exercise capacity at the end of the rehabilitation programme.

CONCLUSIONS

Exercise capacity of patient implanted with a HeartWare^© LVAD increased in the early period after implantation. Rehabilitation allowed implanted patients to have a significantly better evolution compared to non-rehabilitated patients.

Generating pulsatility by pump speed modulation with continuous-flow total artificial heart in awake calves

The purpose of this study was to evaluate the effects of sinusoidal pump speed modulation of the Cleveland Clinic continuous-flow total artificial heart (CFTAH) on hemodynamics and pump flow in an awake chronic calf model. The sinusoidal pump speed modulations, performed on the day of elective sacrifice, were set at ±15 and ± 25% of mean pump speed at 80 bpm in four awake calves with a CFTAH. The systemic and pulmonary arterial pulse pressures increased to 12.0 and 12.3 mmHg (±15% modulation) and to 15.9 and 15.7 mmHg (±25% modulation), respectively. The pulsatility index and surplus hemodynamic energy significantly increased, respectively, to 1.05 and 1346 ergs/cm at ±15% speed modulation and to 1.51 and 3381 ergs/cm at ±25% speed modulation. This study showed that it is feasible to generate pressure pulsatility with pump speed modulation; the platform is suitable for evaluating the physiologic impact of pulsatility and allows determination of the best speed modulations in terms of magnitude, frequency, and profiles.

Thirty years of heart transplantation at the University Medical Centre Utrecht

Purpose

To analyse patient demographics, indications, survival and donor characteristics for heart transplantation (HTx) during the past 30 years at the University Medical Centre Utrecht (UMCU).

Methods

Data have been prospectively collected for all patients who underwent HTx at the UMCU from 1985 until 2015. Patients who were included underwent orthotopic HTx at an age >14 years.

Results

In total, 489 hearts have been transplanted since 1985; 120 patients (25%) had left ventricular assist device (LVAD) implantation prior to HTx. A shift from ischaemic heart disease to dilated cardiomyopathy has been seen as the leading indication for HTx since the year 2000. Median age at HTx was 49 years (range 16–68). Median waiting time and donor age have also increased from 40 to 513 days and from 27 to 44 years respectively (range 11–65). Donor cause of death is now primarily stroke, in contrast to head and brain injury in earlier years. Estimated median survival is 15.4 years (95% confidence interval 14.2–16.6) There is better survival throughout these years.

Conclusion

Over the past 30 years, patient and donor demographics and underlying diseases have shifted substantially. Furthermore, the increase in waiting time due to lack of available donor hearts has led to a rise in the use of LVADs as bridge to transplant. Importantly, an improvement in survival rates is found over time which could be explained by better immunosuppressive therapy and improvements in follow-up care.

MicroRNA Expression in Myocardial Tissue and Plasma of Patients with End-Stage Heart Failure during LVAD Support: Comparison of Continuous and Pulsatile Devices

Aim

Pulsatile flow left ventricular assist devices (pf-LVADs) are being replaced by continuous flow LVADs (cf-LVADs) in patients with end-stage heart failure (HF). MicroRNAs (miRs) play an important role in the onset and progression of HF. Our aim was to analyze cardiac miR expression patterns associated with each type of device, to analyze differences in the regulation of the induced cardiac changes.

Methods and Results

Twenty-six miRs were selected (based on micro-array data and literature studies) and validated in myocardial tissue before and after pf- (n = 17) and cf-LVAD (n = 17) support. Of these, 5 miRs displayed a similar expression pattern among the devices (miR-129*, miR-146a, miR-155, miR-221, miR-222), whereas others only changed significantly during pf-LVAD (miR-let-7i, miR-21, miR-378, miR-378*) or cf-LVAD support (miR-137). In addition, 4 miRs were investigated in plasma of cf-LVAD supported patients (n = 18) and healthy controls (n = 10). Circulating miR-21 decreased at 1, 3, and 6 months after LVAD implantation. MiR-146a, miR-221 and miR-222 showed a fluctuating time pattern post-LVAD.

Conclusion

Our data show a different miR expression pattern after LVAD support, suggesting that differentially expressed miRs are partially responsible for the cardiac morphological and functional changes observed after support. However, the miR expression patterns do not seem to significantly differ between pf- and cf-LVAD implying that most cardiac changes or clinical outcomes specific to each device do not relate to differences in miR expression levels.

Myocardial fibrosis and pro-fibrotic markers in end-stage heart failure patients during continuous-flow left ventricular assist device support

OBJECTIVES

During support with a left ventricular assist device (LVAD), partial reverse remodelling takes place in which fibrosis plays an important role. In this study, we analysed the histological changes and expression of fibrotic markers in patients with advanced heart failure (HF) during continuous-flow LVAD (cf-LVAD) support.

METHODS

In 25 patients, myocardial tissue at the time of LVAD implantation (pre-LVAD) was compared with tissue from the explanted left ventricle (post-LVAD). Interstitial fibrosis and cardiomyocyte size were analysed pre- and post-LVAD. Plasma was obtained from all patients before and during LVAD support. Plasma levels, cardiac mRNA and protein expression of brain natriuretic peptide (BNP), galectin-3 (Gal-3), connective tissue growth factor (CTGF), osteopontin (OPN) and transforming growth factor β-1 were determined.

RESULTS

Fibrosis increased during cf-LVAD unloading (P < 0.05). Cardiomyocytes elongated (P < 0.05), whereas cross-sectional area did not change. BNP, Gal-3, CTGF and OPN were significantly elevated pre-LVAD in comparison with controls. BNP decreased significantly after 1 month of cf-LVAD support (P < 0.001) to near-normal levels. Pro-fibrotic markers remained elevated in comparison with controls.

CONCLUSIONS

cf-LVAD support is associated with lengthening of cardiomyocytes, without alterations in diameter size. Remarkably, myocardial fibrosis increased as well as circulating pro-fibrotic markers. Whether the morphological changes are a direct effect of reduced pulsatility during cf-LVAD support or due to HF progression requires further investigation.

The cost-utility of left ventricular assist devices for end-stage heart failure patients ineligible for cardiac transplantation: a systematic review and critical appraisal of economic evaluations

BACKGROUND

A health technology assessment (HTA) of left ventricular assist devices (LVADs) as destination therapy in patients with end-stage heart failure was commissioned by the Dutch Health Care Insurance Board [College voor Zorgverzekeringen (CVZ)]. In this context, a systematic review of the economic literature was performed to assess the procedure's value for money.

METHODS

A systematic search (updated in December 2013) for economic evaluations was performed by consulting various databases: the HTA database produced by the Centre for Reviews and Dissemination (CRD HTA), websites of HTA institutes, CRD's National Health Service Economic Evaluation Database (NHS EED), Medline (OVID) and EMBASE. No time or language restrictions were imposed and pre-defined selection criteria were used. The two-step selection procedure was performed by two people. References of the selected studies were checked for additional relevant citations.

RESULTS

Six relevant studies were selected. Four economic evaluations relied on the results of the REMATCH trial to compare a pulsatile-flow LVAD with optimal medical therapy (OMT). These evaluations were performed before the publication of the HeartMate II (HM-II) Destination Therapy Trial which compared a pulsatile-flow with a continuous-flow LVAD. Two more recent economic evaluations combined the results of both trials to make an indirect comparison of a continuous-flow LVAD with OMT. In all studies, the largest part of the incremental cost was due to the reimplantation cost of an LVAD, with a device cost of €58,000-€75,000 and about €55,000 for the surgical procedure. The survival gain was highest with a continuous-flow LVAD, up to about three life-years gained (LYG) versus OMT in the most optimistic study. Quality of life (QoL) was improved but measures with a generic utility instrument were lacking, making estimates on quality-adjusted life-years (QALYs) gained more uncertain. Incremental cost-effectiveness ratios of the two most recent studies were on average €107,600 and $198,184 (ca.€145,800) per QALY gained.

CONCLUSIONS

Although LVAD destination therapy improves survival and QoL, it remains questionable as to whether it offers value for money. This conclusion may alter if the price of the device/procedure decreases sufficiently, in combination with further improved outcomes for mortality, adverse events and QoL.

Functional status in left ventricular assist device-supported patients: a literature review

The prevalence of advanced heart failure (HF) is increasing because of the aging population and improvements in HF management strategies. Left ventricular assist device (LVAD) technology and management continue to advance rapidly, and it is anticipated that the number of LVAD implants will increase. LVADs have been demonstrated to extend life and improve outcomes in patients with advanced HF. The purpose of this article is to review and synthesize the evidence on impact of LVAD therapy on functional status. Significant functional gains were demonstrated in patients supported by LVAD throughout the 1st year, with most improvement in distance walked and peak oxygen consumption demonstrated in the 1st 6 months. Interventions to enhance exercise performance have had inconsistent effects on functional status. Poor exercise performance was associated with increased risk of adverse events. Functional status improved with LVAD therapy, although performance remained substantially reduced compared with age-adjusted norms. There is tremendous need to enhance our understanding of factors influencing functional outcomes in this high-risk population.

Heart failure highlights in 2012-2013

Heart failure has become the cardiovascular epidemic of the century. The European Journal of Heart Failure is dedicated to the advancement of knowledge in the field of heart failure management. In 2012 and 2013, several pioneering scientific discoveries and paradigm-shifting clinical trials have been published. In the current paper, we will discuss the most significant novel insights into the pathophysiology, diagnosis, and treatment of heart failure that were published during this period. All relevant research areas are discussed, including pathophysiology, co-morbidities, arrhythmias, biomarkers, clinical trials, and device therapy, including left ventricular assist devices.

Exercise performance of chronic heart failure patients in the early period of support by an axial-flow left ventricular assist device as destination therapy

Axial-flow left ventricular assist devices (LVADs) are increasingly used as destination therapy in end-stage chronic heart failure (CHF), as they improve survival and quality of life. Their effect on exercise tolerance in the early phase after implantation is still unclear. The aim of this study was to evaluate the effect of LVADs on the exercise capacity of a group of CHF patients within 2 months after initiation of circulatory support. Cardiopulmonary exercise test data were collected for 26 consecutive LVAD-implanted CHF patients within 2 months of initiation of assistance; the reference group consisted of 30 CHF patients not supported by LVAD who were evaluated after an episode of acute heart failure. Both LVAD and reference groups showed poor physical performance; LVAD patients achieved lower workload (LVAD: 36.3 ± 9.0 W, reference: 56.6 ± 18.2 W, P < 0.001) but reached a similar peak oxygen uptake (peak VO2 ; LVAD: 12.5 ± 3.0 mL/kg/min, reference: 13.6 ± 2.9 mL/kg/min, P = ns) and similar percentages of predicted peak VO2 (LVAD: 48.8 ± 13.9%, reference: 54.2 ± 15.3%, P = ns). While the values of the O2 uptake efficiency slope were 12% poorer in LVAD patients than in reference patients (1124.2 ± 226.3 vs. 1280.2 ± 391.1; P = ns), the kinetics of VO2 recovery after exercise were slightly better in LVAD patients (LVAD: 212.5 ± 62.5, reference: 261.1 ± 80.2 sec, P < 0.05). In the first 2 months after initiation of circulatory support, axial-flow LVAD patients are able to sustain a low-intensity workload; though some cardiopulmonary exercise test parameters suggest persistence of a marked physical deconditioning, their cardiorespiratory performance is similar to that of less compromised CHF patients, possibly due to positive hemodynamic effects beginning to be produced by the assist device.

Single-centre experience of 85 patients with a continuous-flow left ventricular assist device: clinical practice and outcome after extended support

OBJECTIVES

We evaluated our single-centre clinical experience with the HeartMate II (HM II) left ventricular assist device (LVAD) as a bridge to transplantation (BTT) in end-stage heart failure (HF) patients.

METHODS

Survival rates, echocardiographic parameters, laboratory values and adverse events of 85 consecutive patients supported with a HM II were evaluated.

RESULTS

Overall, mean age was 45 ± 13 years, 62 (73%) were male and non-ischaemic dilatated cardiomyopathy was present in 60 (71%) patients. The median duration of mechanical support was 387 days (IQR 150-600), with a range of 1-1835 days. The 6-month, 1-, 2-, 3- and 4-year survival rates during HM II LVAD support were 85, 81, 76, 76 and 68%, respectively. Echocardiographic parameters demonstrated effective left ventricular unloading, while laboratory results reflected adequate organ perfusion. However, HM II support was associated with adverse events, such as infections in 42 patients (49%; 0.67 events/patient-year), cardiac arrhythmia in 44 (52%; 0.86 events/patient-year), bleeding complications in 32 (38%; 0.43 events/patient-year) and neurological dysfunction in 17 (20%; 0.19 events/patient-year).

CONCLUSIONS

In view of the increasing shortage of donor hearts, HM II LVAD support may be considered a life-saving treatment in end-stage HF patients, with good survival. However, it is still associated with some serious adverse events, of which neurological complications are the most critical.