In-vitro investigation of endothelial monolayer retention on an inflow VAD cannula inside a beating heart phantom.

Ventricular assist devices (VADs) provide an alternative solution to heart transplantation for patients with end-stage heart failure. Insufficient hemocompatibility of VAD components can result in severe adverse events, such as thromboembolic stroke, and readmissions. To enhance VAD hemocompatibility, and avoid thrombus formation, surface modification techniques and endothelialization strategies are employed. In this work, a free form patterning topography is selected to facilitate the endothelialization of the outer surface of the inflow cannula (IC) of a commercial VAD. An endothelialization protocol for convoluted surfaces such as the IC is produced, and the retainment of the endothelial cell (EC) monolayer is evaluated. To allow this evaluation, a dedicated experimental setup is developed to simulate realistic flow phenomena inside an artificial, beating heart phantom with a VAD implanted on its apex. The procedural steps of mounting the system result to the impairment of the EC monolayer, which is further compromised by the developed flow and pressure conditions, as well as by the contact with the moving inner structures of the heart phantom. Importantly, the EC monolayer is better maintained in the lower part of the IC, which is more susceptible to thrombus formation and may therefore aid in minimizing the hemocompatibility related adverse events after the VAD implantation.

Weaning from ventricular assist device support after recovery from left ventricular failure with or without secondary right ventricular failure.

Although complete myocardial recovery after ventricular assist device (VAD) implantation is rather seldom, systematic search for recovery is worthwhile because for recovered patients weaning from VADs is feasible and can provide survival benefits with long-term freedom from heart failure (HF) recurrence, even if a chronic cardiomyopathy was the primary cause for the drug-refractory HF necessitating left ventricular (LVAD) or biventricular support (as bridge-to-transplantation or definitive therapy) and even if recovery remains incomplete. LVAD patients explanted for myoacardial recovery compared to those transplanted from LVAD support showed similar survival rates and a significant proportion of explanted patients can achieve cardiac and physical functional capacities that are within the normal range of healthy controls. In apparently sufficiently recovered patients, a major challenge remains still the pre-explant prediction of the weaning success which is meanwhile reliably possible for experienced clinicians. In weaning candidates, the combined use of certain echocardiography and right heart catheterization parameters recorded before VAD explantation can predict post-weaning cardiac stability with good accuracy. However, in the absence of standardization or binding recommendations, the protocols for assessment of native cardiac improvement and also the weaning criteria differ widely among centers. Currently there are still only few larger studies on myocardial recovery assessment after VAD implantation. Therefore, the weaning practice relies mostly on small case series, local practice patterns, and case reports, and the existing knowledge, as well as the partially differing recommendations which are based mainly on expert opinions, need to be periodically systematised. Addressing these shortcomings, our review aims to summarize the evidence and expert opinion on the evaluation of cardiac recovery during mechanical ventricular support by paying special attention to the reliability of the methods and parameters used for assessment of myocardial recovery and the challenges met in both evaluation of recovery and weaning decision making.

Collaboration and new data in ACTION: a learning health care system to improve pediatric heart failure and ventricular assist device outcomes.

Outcomes in pediatric heart failure and ventricular assist devices (VADs) remain suboptimal. Given the complexity and limited numbers, centers cannot be expected to acquire mastery and generalizable knowledge independently. Recognizing this problem, the community has formed Advanced Cardiac Therapies Improving Outcomes Network (ACTION), a collaborative learning health care system committed to unrelenting collaboration and continuous learning to improve critical outcomes in pediatric heart failure. ACTION is inclusive of all interested parties and believes the fastest and most effective way to make progress is through working together. ACTION's approaches to collaboration and data sharing will be highlighted.

A Valveless Pulsatile Pump for the Treatment of Heart Failure with Preserved Ejection Fraction: A Simulation Study.

PURPOSE: Effective treatment of patients with terminal heart failure and preserved ejection fraction (HFpEF) is an unmet medical need. The aim of this study was to investigate a novel valveless pulsatile pump as a therapeutic option for the HFpEF population through comprehensive in silico investigations. METHODS: The pump was simulated in a numerical model of the cardiovascular system of four HFpEF phenotypes and compared to a typical case of heart failure with reduced ejection fraction (HFrEF). The proposed pump, which was modeled as being directly connected to the left ventricle, features a single valveless inlet and outlet cannula and is driven in co-pulsation with the left ventricle. We collected hemodynamics for two different pump volumes (30 and 60 mL). RESULTS: In all HFpEF conditions, the 30 mL pump improved the cardiac output by approximately 1 L/min, increased the mean arterial pressure by > 11% and lowered the mean left atrial pressure by > 30%. With the larger (60 mL) stroke volume, these hemodynamic improvements were more pronounced. In the HFrEF condition however, these effects were three times less in magnitude. CONCLUSIONS: In this simulation study, the valveless pulsatile device improves hemodynamics in HFpEF patients by increasing the total stroke volume. The hemodynamic benefits are achieved with a small device volume comparable to implantable rotary blood pumps.

Different surgical strategies for implantation of continuous-flow VADs-Experience from Deutsches Herzzentrum Berlin.

OBJECTIVE: This manuscript summarizes our surgical experience with the implantation of recent continuous-flow left ventricular assist devices (LVADs), with special emphasis on the HeartWare HVAD pump. METHODS: THE HEARTWARE HVAD IS, IN OUR EXPERIENCE CURRENTLY IMPLANTED IN FOUR DIFFERENT TECHNIQUES: (I) "Classical" LVAD implantation with heart-lung machine and median sternotomy; (II) "Minimally-invasive" implantation without sternotomy and without heart-lung machine; (III) "Lateral implantation" to the descending aorta; (IV) Using two continuous-flow LVADs for implantable biventricular support. RESULTS: Five-hundred and four HeartWare HVADs have been implanted using the described techniques in our institution up to now. CONCLUSIONS: The HeartWare HVAD is a versatile device. It has been found to be eminently suited to these four different modes of implantation.

Mechanical circulatory support in pediatrics.

There is no reliable published data on the overall prevalence or incidence of heart failure (HF) in children. However, the success of mechanical circulatory support (MCS) in management of HF has raised the prospect of a previously unavailable treatment modality. Orthotopic heart transplant (OHTx) remains the gold standard treatment, but the number of patients requiring this treatment far outweighs the donor availability. It is therefore not surprising to see the popularity of various MCS modalities, with different devices ranging from veno-arterial extra corporeal membrane oxygenation (VA-ECMO) to ventricular assist devices (VADs), which are either para-corporeal or intra-corporeal, with pulsatile or continuous flow. Indication, timing and the choice of the type of mechanical support are crucial so in order to avoid potential lethal complications such as hemorrhage, thrombo-embolism and infections. In the pediatric population, MCS is used mainly as bridge to transplantation but can be used as bridge to recovery in patients with acute myocarditis or following open-heart surgery. Active research is currently underway to develop newer and more durable devices that will assist the pediatric population across all age groups. This research will support different pathologies that have lower incidences of major morbidities, particularly as greater durations of MCS are expected due to a paucity of donors for OHTx. The combined experience developed through the usage of different devices in pediatric and adult populations has led to the to the application of MCS in some subgroups of grown-up congenital heart diseases (CHDs) patients, particularly those with systemic right ventricular failure.

Partial mechanical circulatory support in an ovine model of post-infarction remodeling.

BACKGROUND: Full unloading of the left ventricle (LV) in chronic heart failure (CHF) induces reversal of LV dilation and geometric distortion. In this study we describe the partial unloading effects in ischemic CHF. METHODS: Six weeks after myocardial infarction, sheep were randomized to partial support ("pump," n = 5), as provided by the CircuLite Synergy micro-pump, or to no therapy ("sham," n = 6) for an additional 6 weeks. At baseline, and at 6 and 12 weeks after infarction, pressure-volume (PV) recordings were made. Systolic and diastolic functions were characterized by the end-systolic volume (ESV) where LV end-systolic pressure reached 90 mm Hg (V90), and the end-diastolic volume (EDV) where LV end-diastolic pressure reached 15 mm Hg (V15), respectively. Magnetic resonance imaging (MRI) was performed 6 and 12 weeks after infarction. During autopsy at 12 weeks, isolated LVs were weighed. Histologically, the degree of fibrosis in the non-infarcted area was assessed using systematic randomized sampling, and myocyte hypertrophy was measured by the mean linear intercept method. RESULTS: At 6 weeks, PV measurements showed a V90 and V15 increase (p = NS between groups). Six weeks later, V90 and V15 increased in the sham group. In the pump group, V90 decreased but V15 did not change significantly. At 6 weeks, MRI indicated no significant difference between groups. Six weeks later, in the sham group, EDV and ESV increased significantly. In the pump group, EDV decreased significantly and ESV trended to decrease. Sphericity index increased in the sham group and decreased in the pump group, although not significantly. Explanted LV masses were significantly higher in the sham group than in the pump group. The pump group had a decrease in fibrosis and less myocyte hypertrophy. CONCLUSION: Partial support 6 weeks after major myocardial infarction halts and reverses ventricular dilation and hypertrophy.