The CARMAT total artificial heart.

Implantation of a total artificial heart is an alternative to durable biventricular assist device support in selected patients. We present our initial experience with the implantation of the SynCardia total artificial heart (TAH) in three patients. The first patient, was the first SynCardia (TAH) implantation in the Visegrad Four (V4) countries METHOD: Three patients with severe refractory end stage biventricular heart failure listed for heart transplant were indicated for SynCardia TAH implantationRESULTS: We present in details the perioperative and postoperative outcomes of these patients. The first and the third patient, after 195 and 126 days of TAH support respectively, had asuccessful heart transplants, the second patient died on 11th postoperative day. The cause of death was brain bleeding due to ruptured undiagnosed brain aneurysm. SynCardia TAH is an alternative therapy in patients with end-stage biventricular heart failure waiting for heart transplantation. The SynCardia TAH with pulsatility resembles the physiologic circulation, improves the condition of the patients and increases survival compared to the biventricular assist devices. It is an intermediate step until the development of genetically modified animal hearts, engineered bioartificial hearts or hearts from induced pluripotent stem cells that would replace the failing heart in the patients with end-stage heart disease (Tab. 2, Fig. 1, Ref. 27).

Successful Use of the Total Artificial Heart in the Failing Fontan Circulation

Heart Transplant Outcomes After Total Artificial Heart

Background: The Syncardia Total Artificial Heart (TAH) is used as a bridge to transplant for patients with biventricular heart failure and currently the only FDA approved TAH. There is a dearth in studies investigating its mechanics, hemodynamics, and optimal performance. Previous studies have provided limited characterization of Syncardia's dynamics with respect to platelet activation but did not fully realize a complete dynamic coupled solution. Thus, there is a knowledge gap with regards to understanding the operational capacity and performance characteristics of the TAH. The objective of this study is to characterize the hemodynamic performance of the Syncardia TAH to optimize operational parameters and further understand why the device is an effective bridge to transplant. Methods: COMSOL Multiphysics (COMSOL Inc.) was used to conduct fully coupled fluid-structure interaction simulations of the device in standard operation. The computational model contained a blood fluid volume within Syncardia's housing assembly (ventricle), segmented polyurethane solution (SPUS) diaphragm chamber filled with air, and SynHall valves in the mitral and aortic positions. These components' coupled physics allow for the cohesive motion of the blood volume, diaphragm, and valves by solving the fluid Navier-Stokes and solid motion equations. Results: Figure 1C is flow patterning representative of the left ventricular diastolic filling with the development of the ventricular vortex present within diastole. Negative pressure collapses and deforms the diaphragm as shown in Figure 1D to drive filling during diastole. Figure 1E shows regional stress on the SynHall mitral valve during diastole. Conclusions: We utilized a fully coupled model of the Syncardia to study hemodynamic properties including vorticity and shear stress spatial and temporal distributions. Future work will be to perform failure mode analysis to identify parameters that are associated with thrombosis as well as optimize clinical operational parameters including device setting and associated clinical management.

Shortly after SynCardia total artificial heart (TAH) implant, venovenous extracorporeal membrane oxygenation (ECMO) via a 31 Fr Avalon cannula was used for profound hypoxic lung dysfunction. Immediately after starting ECMO, TAH flow increased by 1.5-2.0 L/min, presumably because of augmented TAH filling by the ECMO jet.

The SynCardia total artificial heart (TAH) currently provides the most definitive option for patients with biventricular failure who are not candidates for isolated left ventricular (LV) assist device placement. The techniques for implantation are adaptable to almost all patients with advanced heart failure, including those with severe biventricular cardiomyopathy, complex congenital heart disease, failed LV assist devices, failed transplantations, and acquired structural heart defects that have failed or are not amenable to conventional surgical treatment. Over the years, the implantation technique has evolved in order to minimize the surgical invasiveness of the procedure, in anticipation of additional future surgery. Meticulous hemostasis with double layer sutures, use of Gore-Tex sheets around the TAH and the pericardial cavity, and use of tissue expanders to avoid contraction of pericardial cavity around the device are discussed in detail in the following report. Additionally, we will provide our experience with implantation of TAH in various challenging scenarios, such as patients with a small chest cavity, congenital heart defects, and simultaneous use of extracorporeal membrane oxygenation (ECMO).

Reduced Pulsatility Induces Periarteritis in Kidney: Role of the Local Renin–Angiotensin System

Total artificial heart(TAH) is the present for patients with biventricular failure, and all other treatments have no significant effect and are unable to obtain donor organs in time or the final choice for receiving organ transplantation.After 50 years of research, TAH, which has already been put into clinical application, has the CardioWest TAH of SynCardia Systems, Abiocor TAH of Abiomedcompany and Carmat TAH of Carmat company.The application of TAH can lead to serious complications.The most common complications include infection, severe postoperative bleeding, and thromboembolism, and other possible complications including liver, kidney, lung, and nervous system dysfunction.Because of various objective reasons, mechanical circulation auxiliary devices, including ventricular assist and all artificial heart, have been limited in our country's research and development and application, and it has become a conventional treatment choice abroad.In addition, in clinical applications, TAH is used for adults over 18 years of age.There is still a long way to go for the application of TAH implantation in children. Key words: Total atificial heart; Heart failure; Complication

The total artificial heart (TAH) is a form of mechanical circulatory support that involves resection of the native ventricles followed by placement of a device that can restore total pulmonary and systemic flow. Given the increasing burden of congestive heart failure and cardiovascular disease, the number of people in need of cardiac replacement therapy will continue to grow. Despite aggressive efforts to expand the donor pool, the number of heart transplants in the United States (US) has plateaued at less than 3000 per year. In addition, there is increasing recognition of the long-term complications of current generation left ventricular assist devices such as progressive aortic insufficiency, complications related to blood trauma, and both early and delayed right ventricular failure. These factors may serve to expand the role of the TAH in the treatment of patients with end-stage heart failure particularly if new generation devices are developed that are durable, have an improved safety profile, and are totally implantable. PURPOSE OF REVIEW: To review the role and current evidence of the use of the TAH in the management of advanced heart failure and discuss development of recent TAHs that may have an impact on the field in the near future. RECENT FINDINGS: Many patients that receive a heart transplant are bridged with a mechanical support device, most commonly a left ventricular assist device (LVAD). However, there is a small subset of patients with profound biventricular (BV) failure or structural abnormalities that preclude LVAD placement, who will require support with a biventricular assist device (BiVAD) or TAH. There are numerous studies showing the efficacy of the TAH in bridging to transplantation. Also, recent studies have shown equal rates of bridging to transplantation between patients receiving a TAH compared to a BiVAD. However, BiVAD support has a higher incidence of stroke in addition to complications related to the native heart such as arrhythmias and valve dysfunction. Currently, there are multiple new generation artificial hearts in both preclinical development and in clinical trials for both bridge to transplant and destination therapy. TAH have been shown to be effective for circulatory support in select patients with end-stage heart failure. Current LVADs are associated with significant long-term complications related to retention of the native heart and pump design. Many of these complications may be addressed by the increased use of cardiac replacement therapy, i.e., total artificial hearts. Multiple generations of both pulsatile and advanced design continuous flow TAH are under development which have the potential to expand the role of TAHs.

Commentary: Supporting a left ventricular assist device to transplant, the right way

An electrohydraulic total artificial heart (EHTAH) system is being developed in our institute. Components of the EHTAH system were evaluated in in vitro and in vivo studies. The system comprises a blood pump system with diaphragm-type ellipsoidal ventricles, an energy converter system consisting of a regenerative pumpbrushless DC motor assembly, and an electronics system with transcutaneous energy transfer (TET) and optical telemetry (TOT) systems. Excellent anatomic fit of the ventricles to the human chest cavity was confirmed by computer graphics based on magnetic resonance imaging. The durability and antithrombogenicity of the blood pump were examined in a series of air-driven chronic implantations into calves for up to 16 weeks. The energy converter is connected to alternate ventricles through flexible conduits, and is placed separately in the abdominal region to minimize anatomic constraints. Maximum output of the pumping unit (the integrated blood pump and energy converter systems) was 10.71/min in a mock circulation at 2500 rpm motor speed. The TET and TOT systems were evaluated in chronic animal studies. The TET system, consisting of a pair of annular coils, demonstrated around 80% DC/DC efficiency for 40 days when 20 W of energy was finally transferred into a simulated load. The TOT system, at a signal transmission rate of 19 200 bits per second (bps) allowed up to 12mm misalignment. These favorable characteristics of the components indicate that the EHTAH system has the capacity to be used as a totally implantable cardiac replacement.

It was 1957 when one of the authors (W.J.K.) began research on total mechanical artificial heart implantation. From that time on it was difficult, until only very recently, to keep an experimental animal alive with an artificial heart for longer than two or three days. However, in 1971 the longstanding question of whether the artificial heart could sustain the animal’s entire circulation beyond the time of recovery from surgery and maintain the animal in a reasonable physiological state with a mechanical pump was answered. To date at least three groups in the country have been able to sustain a calf with an implanted mechanical heart for over three days. These long-term survivors with total mechanical hearts have brought forth a few unanswered questions.

Editorial introductions

Experience With SynCardia Total Artificial Heart as a Bridge to Transplantation in 100 Patients

Pediatric heart transplant candidates have the highest wait-list mortality of all organ candidates. Mechanical circulatory support has improved survival for many patients awaiting transplant. Biventricular mechanical circulatory support remains a particular challenge for pediatric patients. We present the smallest patient (body surface area 0.9 m) to date to receive the 50 cc SynCardia Total Artificial Heart, supported for 278 days before successful heart transplant.