HeartMate 3-a "Step" in the right direction

Cardiac Reverse Remodeling Mediated by HeartMate 3 Left Ventricular Assist Device: Comparison to Older Generation Devices

Currently, the fully magnetically levitated left ventricular assist device (LVAD) HeartMate 3 (HM3) is the only commercially available device for advanced heart failure (HF) patients. However, the left ventricular (LV) functional and structural changes following mechanical unloading and circulatory support (MCS) with the HM3 have not been investigated. We compared the reverse remodeling induced by the HM3 to older generation continuous-flow LVADs. Chronic HF patients (n = 405) undergoing MCS with HeartWare Ventricular Assist Device (HVAD, n = 115), HM3 (n = 186), and HeartMate II (HM2, n = 104) at four programs were included. Echocardiograms were obtained preimplant and at 1, 3, 6, and 12 months following LVAD implantation. There were no differences in the postimplant serial LV ejection fraction (LVEF) between the devices. The postimplant LV internal diastolic diameter (LVIDd) was significantly lower for HM2 at 3 and 6 months compared with HVAD and HM3. The proportion of patients achieving "cardiac reverse remodeling responder" status (defined as LVEF improvement to ≥40% and LVIDD ≤5.9 cm) was 11.9%, and was similar between devices. HeartMate 3 appears to result in similar cardiac reverse remodeling as older generation CF-LVADs, suggesting that the fully magnetically levitated device technology could provide an effective platform to further study and promote cardiac reverse remodeling.

Left Ventricular Assist Device Emergencies: Diagnosis and Management

Durable left ventricular assist devices (LVADs) are a virtually limitless advanced therapy option for an increasingly growing population of patients with end-stage advanced heart failure. As of 2019, 30% to 40% of all patients diagnosed with heart failure were categorized as New York Heart Association class III or IV. In 2018 more than 3.2 million office visits and 1.4 million emergency department visits carried a primary diagnosis of heart failure. Given the rapid growth of the LVAD population, facility in the diagnosis and management of common perioperative and outpatient LVAD emergencies has become of paramount importance in a variety of clinical settings.

Biocompatibility of an apical ring plug for left ventricular assist device explantation: Results of a feasibility pre-clinical study

BACKGROUND

Patients receiving left ventricle assist devices (LVADs) as bridge to recovery remain a minority with 1%-5% of LVADs explanted after improvement of myocardial function. Nevertheless, considering the growing population of patients supported with LVADs, an increasing demand of new explantation strategies is expected in the near future. A novel plug for LVAD explantation has been developed and its biocompatibility profile needs to be proved. This study tested the biocompatibility of this novel plug in an in vivo ovine model.

METHODS

Six adult Blackhead Persian female sheep received plug implantation on the cardiac apex via minimally invasive approach and were clinically observed up to 90 days. Echocardiography was performed to detect thrombus formation or further plug-related complications. After the observation period, euthanasia was performed and samples including the plug and the surrounding tissues were obtained to be analyzed with correlative light and electron microscopy. Organ necrosis, ischemia and peripheral embolism were investigated.

RESULTS

Three animals survived surgery and completed the follow-up time without experiencing clinical complications. Echocardiographic controls excluded the presence of an intracavitary thrombus in the left ventricle (LV). Autopsy confirmed no signs of local infection, LV thrombus or peripheral embolism. Light and electron microscopy revealed an intact epithelium covering a layer of connective tissue on the plug surface facing the heart lumen.

CONCLUSIONS

This novel apical plug for LVAD explantation allows for endothelial and connective tissue growth on its ventricular side within 90 days from surgery. Further studies are required to fully demonstrate the biocompatibility of this apical plug and investigate the optimal anticoagulation regimen to be applied after implantation.

Development of De Novo Aortic Insufficiency in Patients with HeartMate 3

BACKGROUND

De novo aortic insufficiency (AI) is a common adverse event following continuous flow left ventricular assist device (LVAD) placement and is associated with morbidity and mortality. This study aims to compare the development of de novo AI between HeartMate 3 and HeartMate II LVAD recipients.

METHODS

A retrospective review was conducted of clinical characteristics and serial echocardiograms (1 month, 6 months, and 1 year post-implantation) of HeartMate 3 patients implanted between November 2014 and March 2019, and of HeartMate II patients implanted between April 2004 and December 2015 at Columbia University Irving Medical Center. Patients (n=122) were excluded from analysis for a history of aortic valve surgery, concomitant aortic valve surgery with LVAD implant, or more than trace preoperative AI left untreated. De novo AI was defined as development of more than mild AI following LVAD implant.

RESULTS

There were 121 HeartMate 3 patients and 270 HeartMate II patients included in the study. After accounting for competing risks of death and transplantation, there was no significant difference in the development of de novo AI by 1 year post-implantation between HeartMate II and HeartMate 3 patients (p = 0.68). There was no significant difference in severity between HeartMate II and HeartMate 3 among those patients who developed AI up to 1 year post-implantation.

CONCLUSIONS

Development of de novo AI is comparable between HeartMate 3 and HeartMate II patients. There is no significant difference in severity of AI between HM II and HM 3 patients.

Computational analyses of aortic blood flow under varying speed CF-LVAD support

Continuous Flow Left Ventricular Assist Devices (CF-LVADs) generally operate at a constant speed whilst supporting a failing heart. However, constant speed CF-LVAD support may cause complications and increase the morbidity rates in the patients. Therefore, different varying speed operating modes for CF-LVADs have been proposed to generate more physiological blood flow, which may reduce complication rates under constant speed CF-LVAD support. The proposed varying speed CF-LVAD algorithms simulate time-dependant dynamics and three dimensional blood flow patterns in aorta under varying speed CF-LVAD support remain unclear. The aim of this study is to evaluate three dimensional blood flow patterns in a patient-specific aorta model under co-pulsating and counter-pulsating CF-LVAD support modes driven by speed and flow rate control algorithms using numerical simulations. Aortic blood flow was evaluated for 10,000 rpm constant speed CF-LVAD support generating 4.71 L/min mean flow rate over a cardiac cycle. Co-pulsating and counter-pulsating CF-LVAD speed control operated the pump at the same average speed over a cardiac cycle and co-pulsating and counter-pulsating CF-LVAD flow rate control generated the same average flow rate over cardiac cycle as in the constant speed pump support. Simulation results show that the utilised counter-pulsating pump flow rate control may decrease the haemolysis to a third compared to the most commonly employed constant speed pump operating mode. Moreover, CF-LVAD support utilising counter-pulsating pump flow rate control generated the most favourable hemodynamic characteristics, i.e. low Dean number, least wall shear stress and least haemolysis values among the investigated cases.

Hurdles to Cardioprotection in the Critically Ill

Cardiovascular disease is the largest contributor to worldwide mortality, and the deleterious impact of heart failure (HF) is projected to grow exponentially in the future. As heart transplantation (HTx) is the only effective treatment for end-stage HF, development of mechanical circulatory support (MCS) technology has unveiled additional therapeutic options for refractory cardiac disease. Unfortunately, despite both MCS and HTx being quintessential treatments for significant cardiac impairment, associated morbidity and mortality remain high. MCS technology continues to evolve, but is associated with numerous disturbances to cardiac function (e.g., oxidative damage, arrhythmias). Following MCS intervention, HTx is frequently the destination option for survival of critically ill cardiac patients. While effective, donor hearts are scarce, thus limiting HTx to few qualifying patients, and HTx remains correlated with substantial post-HTx complications. While MCS and HTx are vital to survival of critically ill cardiac patients, cardioprotective strategies to improve outcomes from these treatments are highly desirable. Accordingly, this review summarizes the current status of MCS and HTx in the clinic, and the associated cardiac complications inherent to these treatments. Furthermore, we detail current research being undertaken to improve cardiac outcomes following MCS/HTx, and important considerations for reducing the significant morbidity and mortality associated with these necessary treatment strategies.