The Future of Durable Mechanical Circulatory Support: Emerging Technological Innovations and Considerations to Enable Evolution of the Field

The field of durable mechanical circulatory support (MCS) has undergone an incredible evolution over the past few decades, resulting in significant improvements in longevity and quality of life for patients with advanced heart failure. Despite these successes, substantial opportunities for further improvements remain, including in pump design and ancillary technology, perioperative and postoperative management, and the overall patient experience. Ideally, durable MCS devices would be fully implantable, automatically controlled, and minimize the need for anticoagulation. Reliable and long-term total artificial hearts for biventricular support would be available; and surgical, perioperative, and postoperative management would be informed by the individual patient phenotype along with computational simulations. In this review, we summarize emerging technological innovations in these areas, focusing primarily on innovations in late preclinical or early clinical phases of study. We highlight important considerations that the MCS community of clinicians, engineers, industry partners, and venture capital investors should consider to sustain the evolution of the field.

Prehabilitation Using a Cardiac Rehabilitation Program for a Patient With a Total Artificial Heart Prior to Heart Transplantation

INTRODUCTION

The last few decades have been marked by significant advances in mechanical cardiocirculatory support. A total artificial heart (TAH) became a viable therapeutic option for numerous patients as a bridge to heart transplantation, particularly for those in end-stage heart failure. This technology aims to address the various subsequent shortfalls of organs. This report reviews the impact of a prehabilitation on a patient with an Aeson TAH (Carmat).

DISCUSSION

We assessed improvements in functional capacity and quality of life (QoL) in a newly implanted patient following standard cardiac rehabilitation as a prehabilitation program, using 6-min walk test and the Short Form-12 (SF-12) health survey, respectively. Similar functional improvements were observed over a short period of 2 wk compared with a longer protocol for patients with a heart transplant, and superior effects on QoL. The patient was successfully transplanted 5 mo after the TAH implantation.

SUMMARY

Prehabilitation of a patient with a TAH increased both their physical capacity and QoL.

Artificial heart valve reinforced with silk woven fabric and poly (ethylene glycol) diacrylate hydrogels composite

The present study describes the preparation of woven silk fabric (WSF) and poly(ethylene glycol) diacrylate (PEGDA) hydrogel composite reinforced artificial heart valve (SPAHV). Interestingly, the longitudinal and latitudinal elastic modulus of the SPAHV composite can achieve at 54.08 ± 3.29 MPa and 23.96 ± 2.18 MPa, respectively, while its volume/mass swelling ratio and water permeability was 1.9 %/2.8 % and 3 mL/(cm2∙min), respectively, revealing remarkable anisotropic mechanical properties, low water swelling property and water permeability. The in vitro & in vivo biocompatibility and anti-calcification ability of SPAHV were further examined using L929 mouse fibroblasts and Sprague Dawley (SD) male rat model under 8 weeks of subcutaneous implantation. The expression of pro-inflammatory cytokine TNF-α and anti-inflammatory cytokine IL-10 was determined by immunohistochemical staining, as well as the H&E staining and alizarin red staining were accessed. The results showed that the composites possess better biocompatibility, resistance to degradation and anti-calcification ability compared to the control group (p < 0.05). Thus, the SPAHV composite with robust mechanical properties and biocompatibility has potential application for artificial heart valves.

End-stage heart failure: The future of heart transplant and artificial heart

In the last decades, outcomes significantly improved for both heart transplantation and LVAD. Heart transplantation remains the gold standard for the treatment of end stage heart failure and will remain for many years to come. The most relevant limitations are the lack of grafts and the effects of long-term immunosuppressive therapy that involve infectious, cancerous and metabolic complications despite advances in immunosuppression management. Mechanical circulatory support has an irreplaceable role in the treatment of end-staged heart failure, as bridge to transplant or as definitive implantation in non-transplant candidates. Although clinical results do not overcome those of HTx, improvement in the new generation of devices may help to reach the equipoise between the two therapies. This review will go through the evolution, current status and perspectives of both therapeutics.

Cleveland Clinic Continuous-Flow Total Artificial Heart: Progress Report and Technology Update

Cleveland Clinic's continuous-flow total artificial heart (CFTAH) is being developed at our institution and has demonstrated system reliability and optimal performance. Based on the results from recent chronic in vivo experiments, CFTAH has been revised, especially to improve biocompatibility. The purpose of this article is to report our progress in developing CFTAH. To improve biocompatibility, the right impeller, the pump housing, and the motor were reviewed for design revision. Updated design features were based on computational fluid dynamics analysis and observations from in vitro and in vivo studies. A new version of CFTAH was created, manufactured, and tested. All hemodynamic and pump-related parameters were observed and found to be within the intended ranges, and the new CFTAH yielded acceptable biocompatibility. Cleveland Clinic's continuous-flow total artificial heart has demonstrated reliable performance, and has shown satisfactory progress in its development.

A Novel Pumping Principle for a Total Artificial Heart

OBJECTIVE

Total artificial hearts (TAH) serve as a temporary treatment for severe biventricular heart failure. The limited durability and complication rates of current devices hamper long-term cardiac replacement. The aim of this study was to assess the feasibility of a novel valveless pumping principle for a durable pulsatile TAH (ShuttlePump).

METHODS

The pump features a rotating and linearly shuttling piston within a cylindrical housing with two in- and outlets. With a single moving piston, the ShuttlePump delivers pulsatile flow to both systemic and pulmonary circulation. The pump and actuation system were designed iteratively based on analytical and in silico methods, utilizing finite element methods (FEM) and computational fluid dynamics (CFD). Pump characteristics were evaluated experimentally in a mock circulation loop mimicking the cardiovascular system, while hemocompatibility-related parameters were calculated numerically.

RESULTS

Pump characteristics cover the entire required operating range for a TAH, providing 2.5-9 L/min of flow rate against 50-160 mmHg arterial pressures at stroke frequencies of 1.5-5 Hz while balancing left and right atrial pressures. FEM analysis showed mean overall copper losses of 8.84 W, resulting in a local maximum blood temperature rise of <2 K. The CFD results of the normalized index of hemolysis were 3.57 mg/100 L, and 95% of the pump's blood volume was exchanged after 1.42 s.

CONCLUSION AND SIGNIFICANCE

This study indicates the feasibility of a novel pumping system for a TAH with numerical and experimental results substantiating further development of the ShuttlePump.

In Search of the Holy Grail of Artificial Hearts: Are We There Yet?

The total artificial heart (TAH) has a long and rich history, being the product of decades of innovation, hard work, and dedication. This review examines the history of the TAH, a device that has revolutionized the treatment of end-stage biventricular heart failure. It reviews the development of the device from early concepts to the current state-of-the-art device, the SynCardia TAH, which has been implanted in over 2,000 patients worldwide. The article also discusses the challenges and successes experienced by researchers, clinicians, and patients throughout the development of TAH devices. Our focus will also be on discussing the hemostatic alterations in patients implanted with TAH and anticoagulation strategies to decrease associated thromboembolic risks. The article concludes with a look at other novel TAH devices and the future of TAH as an increasingly viable treatment for end-stage heart failure.

Total artificial heart implantation as a bridge to transplantation in the United States

OBJECTIVES

Although the SynCardia total artificial heart (SynCardia Systems, LLC) was approved for use as a bridge to transplantation in 2004 in the United States, most centers do not adopt the total artificial heart as a standard bridging strategy for patients with biventricular failure. This study was designed to characterize the current use and outcomes of patients placed on total artificial heart support.

METHODS

The United Network of Organ Sharing Standard Transplant Research File was queried to identify total artificial heart implantation in the United States between 2005 and 2018. Multivariable Cox regression models were used for risk prediction.

RESULTS

A total of 471 patients (mean age, 49 years; standard deviation, 13 years; 88% were male) underwent total artificial heart implantation. Of 161 transplant centers, 11 centers had cumulative volume of 10 or more implants. The 6-month cumulative incidence of mortality on the total artificial heart was 24.6%. The 6-month cumulative incidence of transplant was 49.0%. The 1-year mortality post-transplantation was 20.0%. Cumulative center volume less than 10 implants was predictive of both mortality on the total artificial heart (hazard ratio, 2.2, 95% confidence interval, 1.5-3.1, P < .001) and post-transplant mortality after a total artificial heart bridge (hazard ratio, 1.5, 95% confidence interval, 1.0-2.2, P = .039).

CONCLUSIONS

Total artificial heart use is low, but the total artificial heart can be an option for biventricular bridge to transplant with acceptable bridge to transplant and post-transplant survival, especially in higher-volume centers. The observation of inferior outcomes in lower-volume centers raises questions as to whether targeted training, center certifications, and minimum volume requirements could improve outcomes for patients requiring the total artificial heart.

Effects of biventricular shunt on pump characteristics in a maglev total artificial heart

Severe left ventricular failure can progress to right ventricular failure, necessitating alternatives to heart transplantation, such as total artificial heart (TAH) treatment. Conventional TAHs encounter challenges associated with miniaturization and hemocompatibility owing to their reliance on mechanical valves and bearings. A magnetically levitated TAH (IB-Heart) was developed, utilizing a magnetic bearing. The IB-Heart features a distinctive biventricular shunt channel situated between the flow paths of the left and right centrifugal blood pumps, simplifying and miniaturizing its control system. However, the impact of these shunt channels remains underexplored. This study aimed to investigate the effects of shunt flow on pump characteristics and assess the IB-Heart's potential to regulate flow balance between systemic and pulmonary circulation. At a rotational speed of 2000 rpm and flow rate range of 0-10 L/min, shunt flow exhibited a minor impact, with a 1.4 mmHg (1.3%) effect on pump characteristics. Shunt flow variation of about 0.13 L/min correlated with a 10 mmHg pressure difference between the pumps' afterload and preload conditions. This variance was linked to changes in the inlet flow rates of the left and right pumps, signifying the ventricular shunt structure's capacity to mirror the function of an atrial shunt in alleviating pulmonary congestion. The IB-Heart's ventricular shunt structure enables passive regulation of left-right flow balance. The findings establish a fundamental technical groundwork for the development of IB-Hearts and TAHs with similar shunt structures. The innovative coupling of centrifugal pumps and the resultant effects on flow dynamics contribute to the advancement of TAH technology.

How do mechanical circulatory support patients die? Autopsy findings for left-ventricular assist device/total artificial heart nonsurvivors

BACKGROUND

Although life saving for end-stage heart failure patients, permanent mechanical circulatory support (MCS) is often the proximate cause of death in those that do not survive to transplant. Autopsy remains the gold standard for diagnosing causes of death and a vital tool for better understanding underlying pathology of nonsurvivors. The aim of this study was to determine the frequency and outcomes of autopsy investigations and compare these with premortem clinical assessment.

METHODS

The autopsy findings and medical records of all patients who underwent left ventricular assist device (LVAD) or total artificial heart (TAH) insertion between June 1994 and April 2022 as a bridge to transplant, but subsequently died pre-heart transplantation were reviewed.

RESULTS

A total of 203 patients had a LVAD or TAH implanted during the study period. Seventy-eight patients (M=59, F=19) died prior to transplantation (age 55 [14] years, INTERMACS=2). Autopsies were conducted in 26 of 78 patients (33%). Three were limited studies. The leading contributor to cause of death was respiratory (14/26), either nosocomial infection or associated with multiorgan failure. Intracranial hemorrhage was the second most common cause of death (8/26). There was a major discrepancy rate of 17% and a minor discrepancy rate of 43%. Autopsy study added a total of 14 additional contributors of death beyond clinical assessment alone (Graphical Abstract).

CONCLUSIONS

Over an observational period of 26years, the frequency of autopsy was low. To improve LVAD/TAH patient survival to transplant, better understanding as to cause of death is required. Patients with MCS have complex physiology and are at high risk of infection and bleeding complications.

Balancing the ventricular outputs of pulsatile total artificial hearts

BACKGROUND

Maintaining balanced left and right cardiac outputs in a total artificial heart (TAH) is challenging due to the need for continuous adaptation to changing hemodynamic conditions. Proper balance in ventricular outputs of the left and right ventricles requires a preload-sensitive response and mechanisms to address the higher volumetric efficiency of the right ventricle.

METHODS

This review provides a comprehensive overview of various methods used to balance left and right ventricular outputs in pulsatile total artificial hearts, categorized based on their actuation mechanism.

RESULTS

Reported strategies include incorporating compliant materials and/or air cushions inside the ventricles, employing active control mechanisms to regulate ventricular filling state, and utilizing various shunts (such as hydraulic or intra-atrial shunts). Furthermore, reducing right ventricular stroke volume compared to the left often serves to balance the ventricular outputs. Individually controlled actuation of both ventricles in a pulsatile TAH seems to be the simplest and most effective way to achieve proper preload sensitivity and left-right output balance. Pneumatically actuated TAHs have the advantage to respond passively to preload changes.

CONCLUSION

Therefore, a pneumatic TAH that comprises two individually actuated ventricles appears to be a more desirable option-both in terms of simplicity and efficacy-to respond to changing hemodynamic conditions.

Next Generation Development of Hybrid Continuous Flow Pediatric Total Artificial Heart Technology: Design-Build-Test

To address the unmet clinical need for pediatric circulatory support, we are developing an operationally versatile, hybrid, continuous-flow, total artificial heart ("Dragon Heart"). This device integrates a magnetically levitated axial and centrifugal blood pump. Here, we utilized a validated axial flow pump, and we focused on the development of the centrifugal pump. A motor was integrated to drive the centrifugal pump, achieving 50% size reduction. The motor design was simulated by finite element analysis, and pump design improvement was attained by computational fluid dynamics. A prototype centrifugal pump was constructed from biocompatible 3D printed parts for the housing and machined metal parts for the drive system. Centrifugal prototype testing was conducted using water and then bovine blood. The fully combined device ( i.e. , axial pump nested inside of the centrifugal pump) was tested to ensure proper operation. We demonstrated the hydraulic performance of the two pumps operating in tandem, and we found that the centrifugal blood pump performance was not adversely impacted by the simultaneous operation of the axial blood pump. The current iteration of this design achieved a range of operation overlapping our target range. Future design iterations will further reduce size and incorporate complete and active magnetic levitation.

Successful utilization of nirmatrelvir/ritonavir and dexamethasone in a patient with total artificial heart and COVID-19: A case report

RATIONALE

Management of coronavirus disease 2019 (COVID-19) has been the subject of extensive research and study, leading to the development of strategies and treatments. Nonetheless, there remains a dearth of information concerning patients who require mechanical circulatory system support. This case report presents one of the first documented cases of successful utilization of nirmatrelvir/ritonavir (Paxlovid) and dexamethasone in the treatment of a patient with a total artificial heart.

PATIENT CONCERNS

The patient in this case study was a 28-year-old male who had been experiencing severe heart failure. In need of a heart transplant, he underwent a procedure for implantation of a total artificial heart as a bridge to transplantation.

DIAGNOSES

Unfortunately, after the surgical intervention, the patient contracted COVID-19, as confirmed by polymerase chain reaction.

INTERVENTIONS

The therapeutic approach involved a 5-day regimen of nirmatrelvir/ritonavir at a dosage of 300/100 mg administered twice daily, along with a daily dosage of 6 mg of dexamethasone.

OUTCOMES

Remarkably, the patient oxygenation level improved on the second day of therapy. Consequently, he was transferred from the intensive care unit to the general floor. After 71 days with the total artificial heart, the patient successfully underwent heart transplantation.

LESSONS

This case report provides a compelling example of the successful application of nirmatrelvir/ritonavir and dexamethasone in the treatment of a COVID-19 patient with a total artificial heart. The positive outcome observed in this case underscores the potential use of these therapeutic agents in this specific patient population. However, it is imperative to conduct further research to corroborate and validate these initial findings. This study lays the foundation for further exploration of the efficacy of these drugs in patients with mechanical circulatory support systems.

Artificial Deep Neural Network for Sensorless Pump Flow and Hemodynamics Estimation During Continuous-Flow Mechanical Circulatory Support

The objective of this study was to compare the estimates of pump flow and systemic vascular resistance (SVR) derived from a mathematical regression model to those from an artificial deep neural network (ADNN). Hemodynamic and pump-related data were generated using both the Cleveland Clinic continuous-flow total artificial heart (CFTAH) and pediatric CFTAH on a mock circulatory loop. An ADNN was trained with generated data, and a mathematical regression model was also generated using the same data. Finally, the absolute error for the actual measured data and each set of estimated data were compared. A strong correlation was observed between the measured flow and the estimated flow using either method (mathematical, R = 0.97, p < 0.01; ADNN, R = 0.99, p < 0.01). The absolute error was smaller in the ADNN estimation (mathematical, 0.3 L/min; ADNN 0.12 L/min; p < 0.01). Furthermore, strong correlation was observed between measured and estimated SVR (mathematical, R = 0.97, p < 0.01; ADNN, R = 0.99, p < 0.01). The absolute error for ADNN estimation was also smaller than that of the mathematical estimation (mathematical, 463 dynes·sec·cm -5 ; ADNN, 123 dynes·sec·cm -5 , p < 0.01). Therefore, in this study, ADNN estimation was more accurate than mathematical regression estimation. http://links.lww.com/ASAIO/A991.

Feasibility of Outpatient Hemodialysis for Patients With Total Artificial Heart: A Case Series

Total artificial hearts (TAH) are used in patients with end-stage heart failure as a bridge-to-transplant. AKI is a common postoperative complication associated with TAH implant. Patients requiring temporary dialysis are denied implantation of TAH due to the inability to provide outpatient (OP) dialysis in the long term. Here we discuss four cases of TAH patients from a single center who were successfully maintained on OP hemodialysis (HD). All four patients were implanted with a 70cc Syncardia TM TAH for NICM. Two patients were implanted as bridge-to-transplant (BTT); one received a heart/kidney transplant and the other received a heart transplant. Two patients were implanted as destination therapy; one was maintained on OP HD until end-of-life, and the other received a heart transplant after becoming transplant eligible. These cases confirm that OP HD is a feasible option for TAH patients with post-implant chronic renal dysfunction provided that the dialysis centers are trained and supported by the implanting program.

HeartMate-3 Ventricular Assist Devices Versus the Total Artificial Heart for Biventricular Support: A Single-Center Series

INTRODUCTION

The SynCardia total artificial heart (TAH) is the only device approved for biventricular support. Continuous flow ventricular assist devices (VAD) in a biventricular configuration (BiVAD) have been used with variable results. The purpose of this report was to examine differences in patient characteristics and outcomes between two HeartMate-3 (HM-3) VADs in comparison with TAH support.

METHODS

All patients who received durable biventricular mechanical support from November 2018 to May 2022 at The Mount Sinai Hospital (New York) were considered. Baseline clinical, echocardiographic, hemodynamic, and outcome data were extracted. Primary outcomes were postoperative survival and successful bridge-to-transplant (BTT).

RESULTS

A total of 16 patients received durable biventricular mechanical support during the study period, of which 6 (38%) patients received two HM-3 VAD pumps as BiVAD support and 10 (62%) patients received a TAH. Overall, TAH patients had a lower median lactate ( p < 0.05) at baseline compared to those on HM-3 BiVAD support yet had higher operative morbidity, lower 6-month survival ( p < 0.05), and a higher rate of renal failure (80 vs . 17%; p = 0.03). However, survival declined to the same rate at 1 year (50%) and was largely because of extracardiac adverse events related to underlying comorbidities (particularly, renal failure and diabetes, p < 0.05). Successful BTT was achieved in 3 out of 6 HM-3 BiVAD patients and in 5 out of 10 TAH patients.

CONCLUSION

In our single center experience, similar outcomes were observed among patients BTT with HM-3 BiVAD compared to those BTT on TAH support despite lower Interagency Registry for Mechanically Assisted Circulatory Support level.

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

BACKGROUND

The SynCardia temporary total artificial heart (TAH-t) is an effective bridge to transplantation for patients with severe biventricular failure. However, granular single-center data from high-volume centers are lacking. We report our experience with the first 100 TAH-t recipients.

METHODS

A prospective institutional database was used to identify 100 patients who underwent 101 TAH-t implantations between 2012 and 2022. Patients were stratified and compared according to Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profile 1 vs 2 or greater. Median follow-up on device support was 94 days (interquartile range, 33-276), and median follow-up after transplantation was 4.6 years (interquartile range, 2.1-6.0).

RESULTS

Overall, 61 patients (61%) were successfully bridged to transplantation and 39 (39%) died on TAH-t support. Successful bridge rates between INTERMACS profile 1 and INTERMACS profile 2 or greater patients were similar (55.6% [95% CI, 40.4%-68.3%] vs 67.4% [95% CI, 50.5%-79.6%], respectively; P = .50). The most common adverse events (rates per 100 patient-months) on TAH-t support included infection (15.8), ischemic stroke (4.6), reoperation for mediastinal bleeding (3.5), and gastrointestinal bleeding requiring intervention (4.3). The most common cause of death on TAH-t support was multisystem organ failure (n = 20, 52.6%). Thirty-day survival after transplantation was 96.7%; survival at 6 months, 1 year, and 5 years after transplantation was 95.1% (95% CI, 85.4%-98.4%), 86.6% (95% CI, 74.9%-93.0%), and 77.5% (95% CI, 64.2%-86.3%), respectively.

CONCLUSIONS

Acceptable outcomes can be achieved in the highest acuity patients using the TAH-t as a bridge to heart transplantation.

Successful support of biventricular heart failure in an adult patient by the Berlin Heart EXCOR system as a bridge to transplant: literature review

Right heart failure is a huge challenge in left ventricular assist device therapy and its occurrence is associated with increased mortality and morbidity. Other options include the use od temporary right ventricular assist device, use of two continous flow biventricular assist devices, use of total artificial heart and the use of paracorporeal biventricular assist devices.In this report we described the successful use of the paracorporeal pulsatile Berlin Heart EXCOR system as a bridge to transplant in a 62 years old patient with end-stage biventricular heart failure (Tab. 1, Fig. 3, Ref. 22). Keywords: biventricular heart failure, mechanical circulatory support, biventricular assist device, Berlin Heart EXCOR system, heart transplantation.

Novel hybrid total artificial heart with integrated oxygenator

There continues to be an unmet therapeutic need for an alternative treatment strategy for respiratory distress and lung disease. We are developing a portable cardiopulmonary support system that integrates an implantable oxygenator with a hybrid, dual-support, continuous-flow total artificial heart (TAH). The TAH has a centrifugal flow pump that is rotating about an axial flow pump. By attaching the hollow fiber bundle of the oxygenator to the base of the TAH, we establish a new cardiopulmonary support technology that permits a patient to be ambulatory during usage. In this study, we investigated the design and improvement of the blood flow pathway from the inflow-to-outflow of four oxygenators using a mathematical model and computational fluid dynamics (CFD). Pressure loss and gas transport through diffusion were examined to assess oxygenator design. The oxygenator designs led to a resistance-driven pressure loss range of less than 35 mmHg for flow rates of 1-7 L/min. All of the designs met requirements. The configuration having an outside-to-inside blood flow direction was found to have higher oxygen transport. Based on this advantageous flow direction, two designs (Model 1 and 3) were then integrated with the axial-flow impeller of the TAH for simulation. Flow rates of 1-7 L/min and speeds of 10,000-16,000 RPM were analyzed. Blood damage studies were performed, and Model 1 demonstrated the lowest potential for hemolysis. Future work will focus on developing and testing a physical prototype for integration into the new cardiopulmonary assist system.

Heart transplantation after total artificial heart bridging-Outcomes over 15 years

BACKGROUND

Data are limited on outcomes after heart transplantation in patients bridged-to-transplantation (BTT) with a total artificial heart (TAH-t).

METHODS

The UNOS database was used to identify 392 adult patients undergoing heart transplantation after TAH-t BTT between 2005 and 2020. They were compared with 11 014 durable left ventricular assist device (LVAD) BTT patients and 22 348 de novo heart transplants (without any durable VAD or TAH-t BTT) during the same period.

RESULTS

TAH-t BTT patients had increased dialysis dependence compared to LVAD BTT and de novo transplants (24.7% vs. 2.7% vs. 3.8%) and higher levels of baseline creatinine and total bilirubin (all p < .001). After transplantation, TAH-t BTT patients were more likely to die from multiorgan failure in the first year (25.0% vs. 16.1% vs. 16.1%, p = .04). Ten-year survival was inferior in TAH-t BTT patients (TAH-t BTT 53.1%, LVAD BTT 61.8%, De Novo 62.6%, p < .001), while 10-year survival conditional on 1-year survival was similar (TAH-t BTT 66.8%, LVAD BTT 68.7%, De Novo 69.0%, all p > .20). Among TAH-t BTT patients, predictors of 1-year mortality included higher baseline creatinine and total bilirubin, mechanical ventilation, and cumulative center volume <20 cases of heart transplantation involving TAH-t BTT (all p < .05).

CONCLUSION

Survival after TAH-t BTT is acceptable, and patients who survive the early postoperative phase experience similar hazards of mortality over time compared to de novo transplant patients and durable LVAD BTT patients.

Exploring the misalignment on the value of further research between payers and manufacturers. A case study on a novel total artificial heart

Payers and manufacturers can disagree on the appropriate level of evidence that is required for new medical devices, resulting in high societal costs due to decisions taken with sub-optimal information. A cost-effectiveness model of a hypothetical total artificial heart was built using data from the literature and the (simulated) results of a pivotal study. The expected value of perfect information (EVPI) was calculated from both the payer and manufacturer perspectives, using net monetary benefit and the company's return on investment respectively. A function was also defined, linking effectiveness to market shares. Additional constraints such as a minimum clinical difference or maximum budget impact were introduced into the company's decisions to simulate additional barriers to adoption. The difference in the EVPI between manufacturers and payers varied greatly depending on the underlying decision rules and constraints. The manufacturer's EVPI depends on the probability of being reimbursed, the uncertainty on the (cost-)effectiveness of the technology, as well as other parameters relating to initial investments, operating costs and market dynamics. The use of Value of information for both perspectives can outline potential misalignments and can be particularly useful to inform early dialogs between manufacturers and payers, or negotiations on conditional reimbursement schemes.

Computational Fluid Dynamics Model of Continuous-Flow Total Artificial Heart: Right Pump Impeller Design Changes to Improve Biocompatibility

Cleveland Clinic is developing a continuous-flow total artificial heart (CFTAH). This novel design operates without valves and is suspended both axially and radially through the balancing of the magnetic and hydrodynamic forces. A series of long-term animal studies with no anticoagulation demonstrated good biocompatibility, without any thromboemboli or infarctions in the organs. However, we observed varying degrees of thrombus attached to the right impeller blades following device explant. No thrombus was found attached to the left impeller blades. The goals for this study were: (1) to use computational fluid dynamics (CFD) to gain insight into the differences in the flow fields surrounding both impellers, and (2) to leverage that knowledge in identifying an improved next-generation right impeller design that could reduce the potential for thrombus formation. Transient CFD simulations of the CFTAH at a blood flow rate and impeller rotational speed mimicking in vivo conditions revealed significant blade tip-induced flow separation and clustered regions of low wall shear stress near the right impeller that were not present for the left impeller. Numerous right impeller design variations were modeled, including changes to the impeller cone angle, number of blades, blade pattern, blade shape, and inlet housing design. The preferred, next-generation right impeller design incorporated a steeper cone angle, a primary/splitter blade design similar to the left impeller, and an increased blade curvature to better align the incoming flow with the impeller blade tips. The next-generation impeller design reduced both the extent of low shear regions near the right impeller surface and flow separation from the blade leading edges, while maintaining the desired hydraulic performance of the original CFTAH design.

Total Artificial Heart Computational Fluid Dynamics: Modeling of Stator Bore Design Effects on Journal-Bearing Performance

Cleveland Clinic's continuous-flow total artificial heart (CFTAH) is a double-ended centrifugal blood pump that has a single rotating assembly with an embedded magnet, which is axially and radially suspended by a balance of magnetic and hydrodynamic forces. The key to the radial suspension is a radial offset between the stator bearing bore and the magnet's steel laminations. This offset applies a radial magnetic force, which is balanced by a hydrodynamic force as the rotating assembly moves to a "force-balanced" radial position. The journal-bearing blood passage is a narrow flow path between the left and right impellers. The intent of this study was to determine the impact of the stator-bearing bore radius on the journal-bearing hydraulic performance while satisfying the geometric design constraints imposed by the pump and motor configuration. Electromagnetic forces on the journal bearing were calculated using the ANSYS EMAG program, Version 18 (ANSYS, Canonsburg, PA). ANSYS CFX Version 19.2 was then used to model the journal-bearing flow paths of the most recent design of the CFTAH. A transient, moving mesh approach was used to locate the steady state, force-balanced position of the rotating assembly. The blood was modeled as a non-Newtonian fluid. The computational fluid dynamics simulations showed that by increasing stator bore radius, rotor power, stator wall average shear stress, and blood residence time in journal-bearing decrease, while blood net flow rate through the bearing increases. The results were used to select a new bearing design that provides an improved performance compared with the baseline design. The performance of the new CFTAH-bearing design will be confirmed through upcoming in vitro and in vivo testing.

Pioneer interview: Lyle D. Joyce, MD, PhD

Lyle D. Joyce, MD, PhD is an adult cardiac surgeon who helped pioneer the artificial heart technology throughout his career. In 1982, he and Dr. William DeVries implanted Jarvik-7 total artificial heart (TAH) in a patient named Barney Clark, which was the first ever destination therapy TAH. Artificial Organs discussed with Dr. Joyce how he came to embark on this career path, his experiences in the operating room during these early days, and what advice he has for the future generation.

Outcomes of Durable Mechanical Circulatory Support in Myocarditis: Analysis of the International Society for Heart and Lung Transplantation Registry for Mechanically Assisted Circulatory Support Registry

Myocarditis can be refractory to medical therapy and require durable mechanical circulatory support (MCS). The characteristics and outcomes of these patients are not known. We identified all patients with clinically-diagnosed or pathology-proven myocarditis who underwent mechanical circulatory support in the International Society for Heart and Lung Transplantation Registry for Mechanically Assisted Circulatory Support registry (2013-2016). The characteristics and outcomes of these patients were compared to those of patients with nonischemic cardiomyopathy (NICM). Out of 14,062 patients in the registry, 180 (1.2%) had myocarditis and 6,602 (46.9%) had NICM. Among patients with myocarditis, duration of heart failure was <1 month in 22%, 1-12 months in 22.6%, and >1 year in 55.4%. Compared with NICM, patients with myocarditis were younger (45 vs. 52 years, P < 0.001) and were more often implanted with Interagency Registry for Mechanically Assisted Circulatory Support profile 1 (30% vs. 15%, P < 0.001). Biventricular mechanical support (biventricular ventricular assist device [BIVAD] or total artificial heart) was implanted more frequently in myocarditis (18% vs. 6.7%, P < 0.001). Overall postimplant survival was not different between myocarditis and NICM (left ventricular assist device: P = 0.27, BIVAD: P = 0.50). The proportion of myocarditis patients that have recovered by 12 months postimplant was significantly higher in myocarditis compared to that of NICM (5% vs. 1.7%, P = 0.0003). Adverse events (bleeding, infection, and neurologic dysfunction) were all lower in the myocarditis than NICM. In conclusion, although myocarditis patients who receive durable MCS are sicker preoperatively with higher needs for biventricular MCS, their overall MCS survival is noninferior to NICM. Patients who received MCS for myocarditis are more likely than NICM to have MCS explanted due to recovery, however, the absolute rates of recovery were low.

Transcutaneous Energy Transmission System for a Totally Implantable Artificial Heart Using a Two-Wire Archimedean Spiral Coil

This paper describes the application of a proposed spiral coil to the transformer of a transcutaneous energy transfer system for a totally implantable artificial heart. To reduce the number of rectifier components in the power receiving circuit, the shape of the power receiving transformer was reviewed. The results indicated that the power transmission efficiency between the transformers was almost the same as that of the receiving transformer with the same shape. In addition, the calculations indicated that the power transmission efficiency including that of the power receiving circuit was increased, and the number of components in the power receiving circuit was reduced.

Elevated Circulating Stem Cells Level is Observed One Month After Implantation of Carmat Bioprosthetic Total Artificial Heart

The Aeson® total artificial heart (A-TAH) has been developed as a total heart replacement for patients at risk of death from biventricular failure. We previously described endothelialization of the hybrid membrane inside A-TAH probably at the origin of acquired hemocompatibility. We aimed to quantify vasculogenic stem cells in peripheral blood of patients with long-term A-TAH implantation. Four male adult patients were included in this study. Peripheral blood mononuclear cells were collected before A-TAH implantation (T0) and after implantation at one month (T1), between two and five months (T2), and then between six and twelve months (T3). Supervised analysis of flow cytometry data confirmed the presence of the previously identified Lin^-CD133⁺CD45^- and Lin^-CD34⁺ with different CD45 level intensities. Lin^-CD133⁺CD45^-, Lin^-CD34⁺CD45^- and Lin^-CD34⁺CD45⁺ were not modulated after A-TAH implantation. However, we demonstrated a significant mobilization of Lin^-CD34⁺CD45^dim (p = 0.01) one month after A-TAH implantation regardless of the expression of CD133 or c-Kit. We then visualized data for the resulting clusters on a uniform manifold approximation and projection (UMAP) plot showing all single cells of the live Lin^- and CD34⁺ events selected from down sampled files concatenated at T0 and T1. The three clusters upregulated at T1 are CD45^dim clusters, confirming our results. In conclusion, using a flow cytometry approach, we demonstrated in A-TAH-transplanted patients a significant mobilization of Lin^-CD34⁺CD45^dim in peripheral blood one month after A-TAH implantation. Using a flow cytometry approach, we demonstrated in A-TAH transplanted patients a significant mobilization of Lin^-CD34⁺CD45^dim in peripheral blood one month after A-TAH implantation. This cell population could be at the origin of newly formed endothelial cells on top of hybrid membrane in Carmat bioprosthetic total artificial heart.

First Clinical Experience With the Pressure Sensor-Based Autoregulation of Blood Flow in an Artificial Heart

The CARMAT-Total Artificial Heart (C-TAH) is designed to provide heart replacement therapy for patients with end-stage biventricular failure. This report details the reliability and efficacy of the autoregulation device control mechanism (auto-mode), designed to mimic normal physiologic responses to changing patient needs. Hemodynamic data from a continuous cohort of 10 patients implanted with the device, recorded over 1,842 support days in auto-mode, were analyzed with respect to daily changing physiologic needs. The C-TAH uses embedded pressure sensors to regulate the pump output. Right and left ventricular outputs are automatically balanced. The operator sets target values and the inbuilt algorithm adjusts the stroke volume and beat rate, and hence cardiac output, automatically. Auto-mode is set perioperatively after initial postcardiopulmonary bypass hemodynamic stabilization. All patients showed a range of average inflow pressures of between 5 and 20 mm Hg during their daily activities, resulting in cardiac output responses of between 4.3 and 7.3 L/min. Operator adjustments were cumulatively only required on 20 occasions. This report demonstrates that the C-TAH auto-mode effectively produces appropriate physiologic responses reflective of changing patients' daily needs and represents one of the unique characteristics of this device in providing almost physiologic heart replacement therapy.

Be still, my beating heart: reading pulselessness from Shakespeare to the artificial heart

Today, patients with heart failure can be kept alive by an artificial heart while they await a heart transplant. These modern artificial hearts, or left ventricular assist devices (LVADs), remove the patient's discernible pulse while still maintaining life. This technology contradicts physiological, historical and sociocultural understandings of the pulse as central to human life. In this essay, we consider the ramifications of this contrast between the historical and cultural importance placed on the pulse (especially in relation to our sense of self) and living with a pulseless LVAD. We argue that the pulse's relationship to individual identity can be rescripted by examining its representation in formative cultural texts like the works of William Shakespeare. Through an integration of historical, literary and biomedical engineering perspectives on the pulse, this paper expands interpretations of pulselessness and advocates for the importance of cultural-as well as biomedical-knowledge to support patients with LVADs and those around them. In reconsidering figurative and literal representations of the heartbeat in the context of technology which removes the need for a pulse, this essay argues that narrative and metaphor can be used to reconceptualise the relationship between the heartbeat and identity.

Total Artificial Heart Update

The SynCardia Total Artificial Heart (TAH, SynCardia Systems, Tucson, AZ) is the only biventricular cardiac replacement approved for bridge to transplantation by the U.S. Food and Drug Administration (FDA) and which carries the European Union CE mark. It has been implanted in about 2000 patients. In experienced centers, 60 to 80 % of implanted patients have been transplanted and over 80 % of those transplanted have lived for over 1 year. The SynCardia TAH has supported potential cardiac recipients with irreversible biventricular failure for up to 6 years, providing physiologic pulsatile flows of 6 to 8 L/min at filling pressures of less than 10 mmHg allowing for optimal perfusion and recovery of organs such as the kidneys and liver. It is a tested device that provides a method for recovering potential transplant candidates who rapidly decompensate from biventricular failure or who have chronic cardiac failure from a variety of etiologies. This article covers the history, mechanical function and monitoring, implantation, patient selection and management, and outpatient use. It also reviews outcome data from the original FDA study as well as contemporary data from experienced centers.

Aeson-The Carmat total artificial heart is approved for enrollment in the United States

Aeson, the Carmat Total Artificial Heart has been recently approved by the FDA for beginning enrollment in the United States. This follows their recent attainment of CE marking in 2020.

A Heart without Life: Artificial Organs and the Lived Body

The use of artificial organs is likely to increase in the future, given technological advances, increases in chronic diseases, and limited donor organs. This article examines how artificial organs could affect people's experience and conceptualization of bodies and our understanding of the relation of body to self. I focus on artificial heart devices and argue that these have two conflicting potential influences. First, they may influence people to regard the body as machinelike and separable from the self. Second, they may effect changes to subjective experience that can be understood as changes to the self, confirming the self's embodiment. My primary purpose is to increase our understanding of what might change if it becomes more usual to have a body that is partly nonorganic. But I also argue that the analysis points to potential ethical concerns related to strengthening biomedical conceptions of the body and to the devaluing of bodies and body parts.

An organosynthetic dynamic heart model with enhanced biomimicry guided by cardiac diffusion tensor imaging

The complex motion of the beating heart is accomplished by the spatial arrangement of contracting cardiomyocytes with varying orientation across the transmural layers, which is difficult to imitate in organic or synthetic models. High-fidelity testing of intracardiac devices requires anthropomorphic, dynamic cardiac models that represent this complex motion while maintaining the intricate anatomical structures inside the heart. In this work, we introduce a biorobotic hybrid heart that preserves organic intracardiac structures and mimics cardiac motion by replicating the cardiac myofiber architecture of the left ventricle. The heart model is composed of organic endocardial tissue from a preserved explanted heart with intact intracardiac structures and an active synthetic myocardium that drives the motion of the heart. Inspired by the helical ventricular myocardial band theory, we used diffusion tensor magnetic resonance imaging and tractography of an unraveled organic myocardial band to guide the design of individual soft robotic actuators in a synthetic myocardial band. The active soft tissue mimic was adhered to the organic endocardial tissue in a helical fashion using a custom-designed adhesive to form a flexible, conformable, and watertight organosynthetic interface. The resulting biorobotic hybrid heart simulates the contractile motion of the native heart, compared with in vivo and in silico heart models. In summary, we demonstrate a unique approach fabricating a biomimetic heart model with faithful representation of cardiac motion and endocardial tissue anatomy. These innovations represent important advances toward the unmet need for a high-fidelity in vitro cardiac simulator for preclinical testing of intracardiac devices.

[Development and Application of Permanent Magnet Motor and Its Control in the Field of Artificial Blood Pump]

Permanent magnet motor has been widely used in the field of artificial heart pump due to its high power density, high stability and easy control. In this paper, the development history and research progress of permanent magnet motor for blood pump were described. Firstly, the motors were classified according to their structures and application scenarios. And then, the measures taken by different types of motors to meet the corresponding performance requirements were introduced, and the specific application cases were given. After that, commonly used control algorithms of these motors were enumerated. What's more, the advantages and disadvantages of the control algorithms and their application emphasis were carefully explained. Finally, the paper was summarized in short.

Reliability of left atrial pressure estimation from left ventricular filling measurement in a total artificial heart

A physiological control of a total artificial heart (TAH) requires reliable information on left arterial pressure (LAP). When LAP is derived indirectly from intrinsic TAH parameters like end diastolic volume (EDV) and diastole duration (Td), the transfer function and associated uncertainties need to be well understood.We derived a computational equivalent to a hydraulic model consisting of the venous compliance, the heart valve and the pump chamber, and studied the filling phase in cases of different venous compliance. We calculated a family of curves of pump chamber volume as a function of time for different venous compliances and LAP. To visualize the LAP transfer function and uncertainties associated to EDV, Td measurement error and unknown venous compliance a family of similar curves in the vicinity of assumed measurement was found and visualised in the parameter space.Results were in a realistic absolute range and showed expected trends despite some simplifications in the simulation model. The venous compliance has no significant influence on LAP values extracted from EDV and Td, except at very low values. The uncertainty in the extracted LAP is particularly high for high EDV and short Td.A physiological regulation therefore does not have to be individually adapted to the patient's venous compliances, but has to deal with uncertainties in the input values like blood pressures extracted from intrinsic device parameters.

Generation of bioartificial hearts using decellularized scaffolds and mixed cells

BACKGROUND

Patients with end-stage heart failure must receive treatment to recover cardiac function, and the current primary therapy, heart transplantation, is plagued by the limited supply of donor hearts. Bioengineered artificial hearts generated by seeding of cells on decellularized scaffolds have been suggested as an alternative source for transplantation. This study aimed to develop a tissue-engineered heart with lower immunogenicity and functional similarity to a physiological heart that can be used for heart transplantation.

MATERIALS AND METHODS

We used sodium dodecyl sulfate (SDS) to decellularize cardiac tissue to obtain a decellularized scaffold. Mesenchymal stem cells (MSCs) were isolated from rat bone marrow and identified by flow cytometric labeling of their surface markers. At the same time, the multi-directional differentiation of MSCs was analyzed. The MSCs, endothelial cells, and cardiomyocytes were allowed to adhere to the decellularized scaffold during perfusion, and the function of tissue-engineered heart was analyzed by immunohistochemistry and electrocardiogram.

RESULTS

MSCs, isolated from rats differentiated into cardiomyocytes, were seeded along with primary rat cardiomyocytes and endothelial cells onto decellularized rat heart scaffolds. We first confirmed the pluripotency of the MSCs, performed immunostaining against cardiac markers expressed by MSC-derived cardiomyocytes, and completed surface antigen profiling of MSC-derived endothelial cells. After cell seeding and culture, we analyzed the performance of the bioartificial heart by electrocardiography but found that the bioartificial heart exhibited abnormal electrical activity. The results indicated that the tissue-engineered heart lacked some cells necessary for the conduction of electrical current, causing deficient conduction function compared to the normal heart.

CONCLUSION

Our study suggests that MSCs derived from rats may be useful in the generation of a bioartificial heart, although technical challenges remain with regard to generating a fully functional bioartificial heart.

SynCardia, total artificial heart, as a bridge to transplant

INTRODUCTION

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 a successful heart transplants, the second patient died on 11th postoperative day. The cause of death was brain bleeding due to ruptured undiagnosed brain aneurysm.

CONCLUSION

  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).

Histological investigation of the titanium fiber mesh with one side sealed with non-porous material for its application to the artificial heart system

In this study, we investigated tissue-inducing characteristics of a titanium fiber mesh disk with one surface sealed with a non-porous material. We used sintered titanium fiber mesh (Hi-Lex Co., Zellez™, Hyogo, Japan) having a titanium fiber diameter of 50 µm and volumetric porosity of the titanium fiber mesh of 87% with an average pore size of 200 µm. The titanium fiber mesh is disk-shaped with a dimeter of 5 mm and a thickness of 1.5 mm. One side of the titanium fiber mesh disk was sealed with silicone rubber adhesive that has no venomousness and the sealed titanium fiber mesh disks were implanted in rats under the skin of the dorsal region, and they were extracted in the 4th and 12th postoperative weeks. We investigated the distribution of capillaries; also we estimated the extent of the spread of oxygen from capillaries using the diffusion equation. Microscopic observation showed that the distribution of capillaries was mainly confined to the area around the sealed titanium fiber mesh disk and that connective tissue inside the sealed titanium fiber mesh disk seemed to be in a poor condition. From estimation of the extent of the spread of oxygen from capillaries, an area in which oxygen was poorly supplied may exist in the center of the sealed titanium fiber mesh disk. In conclusion, for application of the sealed titanium fiber mesh to an artificial heart system, the thickness of the titanium fiber mesh is an important factor for keeping the inside tissue in a healthy condition.

Initial in vitro testing of a paediatric continuous-flow total artificial heart

OBJECTIVES

Mechanical circulatory support has become standard therapy for adult patients with end-stage heart failure; however, in paediatric patients with congenital heart disease, the options for chronic mechanical circulatory support are limited to paracorporeal devices or off-label use of devices intended for implantation in adults. Congenital heart disease and cardiomyopathy often involve both the left and right ventricles; in such cases, heart transplantation, a biventricular assist device or a total artificial heart is needed to adequately sustain both pulmonary and systemic circulations. We aimed to evaluate the in vitro performance of the initial prototype of our paediatric continuous-flow total artificial heart.

METHODS

The paediatric continuous-flow total artificial heart pump was downsized from the adult continuous-flow total artificial heart configuration by a scale factor of 0.70 (1/3 of total volume) to enable implantation in infants. System performance of this prototype was evaluated using the continuous-flow total artificial heart mock loop set to mimic paediatric circulation. We generated maps of pump performance and atrial pressure differences over a wide range of systemic vascular resistance/pulmonary vascular resistance and pump speeds.

RESULTS

Performance data indicated left pump flow range of 0.4-4.7 l/min at 100 mmHg delta pressure. The left/right atrial pressure difference was maintained within ±5 mmHg with systemic vascular resistance/pulmonary vascular resistance ratios between 1.4 and 35, with/without pump speed modulation, verifying expected passive self-regulation of atrial pressure balance.

CONCLUSIONS

The paediatric continuous-flow total artificial heart prototype met design requirements for self-regulation and performance; in vivo pump performance studies are ongoing.

Early in vivo experience with the pediatric continuous-flow total artificial heart

BACKGROUND

Heart transplantation in infants and children is an accepted therapy for end-stage heart failure, but donor organ availability is low and always uncertain. Mechanical circulatory support is another standard option, but there is a lack of intracorporeal devices due to size and functional range. The purpose of this study was to evaluate the in vivo performance of our initial prototype of a pediatric continuous-flow total artificial heart (P-CFTAH), comprising a dual pump with one motor and one rotating assembly, supported by a hydrodynamic bearing.

METHODS

In acute studies, the P-CFTAH was implanted in 4 lambs (average weight: 28.7 ± 2.3 kg) via a median sternotomy under cardiopulmonary bypass. Pulmonary and systemic pump performance parameters were recorded.

RESULTS

The experiments showed good anatomical fit and easy implantation, with an average aortic cross-clamp time of 98 ± 18 minutes. Baseline hemodynamics were stable in all 4 animals (pump speed: 3.4 ± 0.2 krpm; pump flow: 2.1 ± 0.9 liters/min; power: 3.0 ± 0.8 W; arterial pressure: 68 ± 10 mm Hg; left and right atrial pressures: 6 ± 1 mm Hg, for both). Any differences between left and right atrial pressures were maintained within the intended limit of ±5 mm Hg over a wide range of ratios of systemic-to-pulmonary vascular resistance (0.7 to 12), with and without pump-speed modulation. Pump-speed modulation was successfully performed to create arterial pulsation.

CONCLUSION

This initial P-CFTAH prototype met the proposed requirements for self-regulation, performance, and pulse modulation.

Self-Management Protocol for a Moving-Actuator Type Artificial Heart

In this paper, we describe the development of a self-management protocol for a controller of a moving-actuator type artificial heart, AnyHeart™. The developed protocol analyzes motor current signals and detects abnormal pumping statuses. If preset abnormal pumping statuses are detected by an implemented algorithm, a controller triggers an emergency management procedure and transmits an alarm message to predetermined medical and engineering staffs via a cellular phone network to notify them of an abnormal pumping status occurrence and its likely cause.

Results of in vitro performance experiments showed that the developed protocol can detect simulated abnormalities in motor current, manage the operating status of the blood pump during an emergency, and transmit an alarm message as desired.

Wireless Patient Monitoring System for a Moving-Actuator Type Artificial Heart

In this study, we developed a wireless monitoring system for outpatients equipped with a moving-actuator type pulsatile bi-ventricular assist device, AnyHeart™. The developed monitoring system consists of two parts; a Bluetooth-based short-distance self-monitoring system that can monitor and control the operating status of a VAD using a Bluetooth-embedded personal digital assistant or a personal computer within a distance of 10 meters, and a cellular network-based remote monitoring system that can continuously monitor and control the operating status of AnyHeart™ at any location.

Results of in vitro experiments demonstrate the developed system's ability to monitor the operational status of an implanted AnyHeart™.

A Preclinical Cadaver Fitting Study of Implantable Biventricular Assist Device - AnyHeart™

A multifunctional, Korean-made artificial heart (AnyHeart™) was developed, and prior to its clinical application, a cadaver-fitting study was performed. The study proposed to determine the optimal cannulation approach, implantation technique and route of the cannula to minimize the organ compression of AnyHeart™. The anatomical feasibility and a variety of surgical techniques were evaluated using ten preserved, human cadavers. Implanting AnyHeart™ with ease is possible using various approaches, including a median sternotomy, and a right or left lateral thoracotomy. The lateral thoracotomy approach is shown to be safe and reproducible, especially in patients who have already undergone an operation that used a median sternotomy. The results of this study will guide improvements in the designs of cannulae and AnyHeart™ for future clinical applications.

The MiniACcor: Constructive Redesign of an Implantable Total Artificial Heart, Initial Laboratory Testing and Further Steps

The Aachen Total Artificial Heart (ACcor) has been under development at the Helmholtz Institute in Aachen over the last decade. It may serve as a bridge to transplant or as a long-term replacement of the natural heart. Based upon previous in vivo experiments with the ACcor total artificial heart, it was decided to optimize and redesign the pump unit. Smaller dimensions, passive filling and separability into three components were the three main design goals. The new design is called the MiniACcor, which is about 20% smaller than its predecessor, and weighs only 470 grams. Also its external driver/control unit was miniaturized and a new microcontroller was selected. To validate the design, it was extensively tested in laboratory mock loops. The MiniACcor was able to pump between 4.5 and 7 l/min at different pump rates against normal physiological pressures. Several requirements for the future compliance chamber and transcutaneous energy transmission (TET) system were also measured in the same mock loop. Further optimization and validation are being performed in cooperation with the Heart and Diabetes Centre North Rhine-Westphalia.

Attitude of the Saudi community towards heart donation, transplantation, and artificial hearts

Objectives:

To understand the attitudes of the Saudi population towards heart donation and transplantation.

Methods:

A survey using a questionnaire addressing attitudes towards organ transplantation and donation was conducted across 18 cities in Saudi Arabia between September 2015 and March 2016.

Results:

A total of 1250 respondents participated in the survey. Of these, approximately 91% agree with the concept of organ transplantation but approximately 17% do not agree with the concept of heart transplantation; 42.4% of whom reject heart transplants for religious reasons. Only 43.6% of respondents expressed a willingness to donate their heart and approximately 58% would consent to the donation of a relative’s organ after death. A total of 59.7% of respondents believe that organ donation is regulated and 31.8% fear that the doctors will not try hard enough to save their lives if they consent to organ donation. Approximately 77% believe the heart is removed while the donor is alive; although, the same proportion of respondents thought they knew what brain death meant.

Conclusion:

In general, the Saudi population seem to accept the concept of transplantation and are willing to donate, but still hold some reservations towards heart donation.