Implantable Artificial Heart Research Articles

Total Artificial Heart Implantation as a Bridge to Transplantation in Slovakia.

Although left ventricular assist device implantation represents the majority of durable mechanical circulatory support implants for patients with advanced heart failure, as many as 20 to 30% will subsequently have right heart failure requiring extended inotropic support or short-term mechanical circulatory support, and the total artificial heart is an established tool in the bridge to transplant armamentarium. The aim of this short report is to present our center's experience with the use of SynCardia total artificial heart. Between November 2017 and April 2021, 10 SynCardia total artificial heart devices were implanted. Of the 10 patients who underwent total artificial heart implantation, 6 (60%) were successfully bridged to transplant with a median time of 6.5 (interquartile range [IQR] 6-8) months, and 4 patients died on device support during the index hospitalization. The 30-day, 1-year, and 3-year survival rates after heart transplantation were the same at 66.7% (4/6). Despite the uncertain future of total artificial hearts, it remains a viable option for patients who require biventricular bridge to transplant or for a select subset of patients with advance heart failure who may not otherwise survive.

Outcomes after SynCardia® temporary total artificial heart implantation: A 20-year single-center experience in 196patients.

The SynCardia® temporary total artificial heart (TAH) serves as a mechanical circulatory support device for patients suffering from irreversible biventricular failure. This retrospective study analyzed 196 consecutive patients who underwent TAH implantation at our center from 2001 to 2021. We assessed survival rates and all-cause mortality during TAH support, including survival post-heart transplantation. The median age of patients was 55 years, with 88% being male. The primary diagnoses included cardiomyopathy (43.9%), acute myocardial infarction (26.5%), and postcardiotomy heart failure (15.5%). At implantation, 87.2% of patients were classified as INTERMACS Profile 1. The median duration of support was 96 days (IQR: 23-227). Survival rates at 1, 6, and 12 months were 72%, 41%, and 34%, respectively. Postoperative rethoracotomy was necessary in 44.4% of patients; 39.3% experienced neurological events and 24.6% developed gastrointestinal bleeding. Overall, 64.8% of patients died while on support, primarily due to multiple organ failure (55.9%). Factors such as older age, higher bilirubin levels, postcardiotomy and specific underlying diagnoses were independent predictors of mortality during TAH support. On a positive note, 35.2% of patients underwent successful heart transplants, with 1-, 5-, and 10-year posttransplant survival rates of 65%, 58%, and 51%, respectively. While high mortality rates persist among patients with biventricular failure, the SynCardia® TAH offers a viable interim solution for critically ill patients, particularly those who can be successfully bridged to heart transplantation.

HeartMate 3 implantation with an emphasis on the biventricular configuration.

Right ventricular failure following implantation of a durable left ventricular assist device (LVAD) is a major driver of mortality. Reported survival following biventricular (BiVAD) or total artificial heart (TAH) implantation remains substantially inferior to LVAD alone. We report our outcomes with LVAD and BiVAD HeartMate 3 (HM3). Consecutive patients undergoing implantation of an HM3 LVAD between November 2014 and December 2021, at The Alfred, Australia were included in the study. Comparison was made between the BiVAD and LVAD alone groups. A total of 86 patients, 65 patients with LVAD alone and 21 in a BiVAD configuration underwent implantation. The median age of the LVAD and BiVAD groups was 56 years (Interquartile range 46-62) and 49 years (Interquartile range 37-55), respectively. By 4 years after implantation, 54% of LVAD patients and 43% of BiVAD patients had undergone cardiac transplantation. The incidence of stroke in the entire experience was 3.5% and pump thrombosis 5% (all in the RVAD). There were 14 deaths in the LVAD group and 1 in the BiVAD group. The actuarial survival for LVAD patients at 1 year was 85% and BiVAD patients at 1 year was 95%. The application of HM 3 BiVAD support in selected patients appears to offer a satisfactory solution to patients requiring biventricular support.

Zwitterionic coating assisted by dopamine with metal-phenolic networks loaded on titanium with improved biocompatibility and antibacterial property for artificial heart.

Introduction: Titanium (Ti) and Ti-based alloy materials are commonly used to develop artificial hearts. To prevent bacterial infections and thrombus in patients with implanted artificial hearts, long-term prophylactic antibiotics and anti-thrombotic drugs are required, and this may lead to health complications. Therefore, the development of optimized antibacterial and antifouling surfaces for Ti-based substrate is especially critical when designing artificial heart implants. Methods: In this study, polydopamine and poly-(sulfobetaine methacrylate) polymers were co-deposited to form a coating on the surface of Ti substrate, a process initiated by Cu2+ metal ions. The mechanism for the fabrication of the coating was investigated by coating thickness measurements as well as Ultraviolet-visible and X-ray Photoelectron (XPS) spectroscopy. Characterization of the coating was observed by optical imaging, scanning electron microscope (SEM), XPS, atomic force microscope (AFM), water contact angle and film thickness. In addition, antibacterial property of the coating was tested using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as model strains, while the material biocompatibility was assessed by the antiplatelet adhesion test using platelet-rich plasma and in vitro cytotoxicity tests using human umbilical vein endothelial cells and red blood cells. Results and discussion: Optical imaging, SEM, XPS, AFM, water contact angle, and film thickness tests demonstrated that the coating was successfully deposited on the Ti substrate surface. The biocompatibility and antibacterial assays showed that the developed surface holds great potential for improving the antibacterial and antiplatelet adhesion properties of Ti-based heart implants.

Hyponatremia in Stable Patients with Advanced Heart Failure: Association to Hemodynamics and Outcome

Introduction: Hyponatremia is associated with worse outcomes in patients with chronic heart failure (HF) and reduced ejection fraction (HFrEF). However, it is unclear whether the worse prognosis is driven by hemodynamic derangement and how this potentially could be associated with hyponatremia. Methods: The study included 502 patients with HFrEF evaluated for advanced HF therapies, who underwent a right heart catheterization (RHC). Hyponatremia was defined as p-Na ≤136 mmol/L. The risk of all-cause mortality and a composite endpoint including mortality, left ventricular assist device (LVAD) implantation, implantation of total artificial heart (TAH), or heart transplantation (HTx) was evaluated using Cox regression analyses and Kaplan-Meier models. Results: Included patients were predominantly men 79% and had a median age of 54 years (IQR: 43–62). A third (165) of the patients had hyponatremia. In both univariate and multivariate regression analyses, p-Na was associated with increased central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), and mean pulmonary artery pressure (mPAP) but not with cardiac index. Hyponatremia was significantly associated with the combined endpoint (HR: 1.36 [95% CI, 1.07–1.74]; p = 0.01), but not all-cause mortality in adjusted Cox models. Conclusion: In stable HFrEF patients evaluated for advanced HF therapies, lower p-Na was associated with more deranged invasive hemodynamic measurements. Hyponatremia remained significantly associated with the combined endpoint but not all-cause mortality in adjusted Cox models. The study suggests that the increased mortality associated with hyponatremia in HFrEF patients could partly be driven by hemodynamic derangement.

Uric acid in advanced heart failure: relation to central haemodynamics and outcome

ObjectiveThe role of hyperuricaemia as a prognostic maker has been established in chronic heart failure (HF) but limited information on the association between plasma uric acid (UA) levels and central...

Bioprosthetic Total Artificial Heart Implantation Does Not Induce Chronic Inflammation.

The Aeson total artificial heart (A-TAH) has been developed for patients at risk of death from biventricular failure. We aimed to assess the inflammatory status in nine subjects implanted with the A-TAH in kinetics over one year. Laboratory assessment of leukocyte counts, inflammatory cytokines assay, and peripheral blood mononuclear cell collection before and after A-TAH implantation. Leukocyte counts were not significantly modulated according to time after A-TAH implantation (coefficient of the linear mixed effect model with 95% CI, -0.05 (-0.71 to -0.61); p = 0.44). We explored inflammatory cytokine after A-TAH and did not observe, at any time, a modified profile compared to pre-implantation values (all p -values > 0.05). Finally, we compared the distribution of circulating immune cell subpopulations identified based on sequential expression patterns for multiple clusters of differentiation. None of the population explored had significant modulation during the 12-month follow-up (all p -values > 0.05). In conclusion, using a cytokine multiplex assay combined with a flow cytometry approach, we demonstrated the absence of inflammatory signals in peripheral blood over a period of 12 months following A-TAH implantation.

Inducing-Yang-to-Yin tuina therapy for relief of insomnia in a patient with artificial heart implantation and related nursing measures

Inducing-Yang-to-Yin tuina therapy for relief of insomnia in a patient with artificial heart implantation and related nursing measures

Intermediate-dose prophylactic anticoagulation with low molecular weight heparin is safe after bioprosthetic artificial heart implantation.

The use of anti-thrombotic therapy is mandatory in classic mechanical circulatory support (MCS) systems in order to decrease the risk of thromboembolic complications associated with poor device hemocompatibility. For most long term MCS, an antiplatelet agent and a vitamin K antagonist (VKA) are both used at therapeutic doses. The autoregulated Aeson total artificial heart (A-TAH, Carmat SA, Vélizy-Villacoublay, France) is designed to replace the heart in patients with end-stage heart failure. It provides pulsatile flow and contains bio-prosthetic blood-contacting materials.

Total artificial heart as a bridge to transplantation.

Since the first implantation of a total artificial heart (TAH) 50 years ago the devices and technique have evolved to provide reliable support for patients with biventricular failure as a bridge to heart transplant. The purpose of this review is to discuss the history and evolution of devices, current devices, critical aspects of patient selection, tips and pitfalls of implantation, and future directions. The most studied device on the market is the SynCardia TAH, which has been implanted in over 2000 patients worldwide and is the only device that is currently Food and Drug Administration approved as a bridge to transplant. The overall survival in patients supported by the device at 1 year is 42% while those that make it to transplant have a 1 year post transplant survival of 83%. A newer device the Aeson TAH (Carmat, Velizy-Villacoublay, France) was first implanted in France in 2013 and is currently under clinical trial in the United States. Significant progress has been made in both the technology and technique of TAH implantation and these devices remain both a reliable and sometimes only option for patients with severe biventricular heart failure.

Aortic Pulsatility Index: A New Haemodynamic Measure with Prognostic Value in Advanced Heart Failure.

Aim: To test if the newly described haemodynamic variable, aortic pulsatility index (API), predicts long-term prognosis in advanced heart failure (HF). Methods: A single-centre study on 453 HF patients (median age: 51 years; left ventricular ejection fraction [LVEF]: 19% ± 9%) referred for right heart catheterisation. API was calculated as pulse pressure/pulmonary capillary wedge pressure. Results: Log(API) correlated significantly with central venous pressure (CVP; p<0.001) and cardiac index (p<0.001) in univariable regression analysis. CVP remained associated with log(API) in a multivariable analysis including cardiac index, heart rate, log(NT-proBNP [N-terminal proB-type natriuretic peptide]), LVEF, New York Heart Association (NYHA) class III or IV and sex (p=0.01). In univariable Cox models, log(API) was a significant predictor of freedom from the combined endpoint of death, left ventricular assist device implantation, total artificial heart implantation or heart transplantation (HR 0.33; (95% CI [0.22–0.49]); p<0.001) and all-cause mortality (HR 0.56 (95% CI [0.35–0.90]); p=0.015). After adjusting for age, sex, NYHA class III or IV and estimated glomerular filtration rate in multivariable Cox models, log(API) remained a significant predictor for the combined endpoint (HR 0.33; 95% CI [0.20–0.56]; p<0.001) and all-cause mortality (HR 0.49; 95% CI [0.26–0.96]; p=0.034). Conclusion: API was strongly associated with right-sided filling pressure and independently predicted freedom from the combined endpoint and all-cause mortality.

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

ObjectivesAlthough 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. MethodsThe 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. ResultsA 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). ConclusionsTotal 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.

Novel Use of Pulmonary Artery Pressure Monitoring After a Total Artificial Heart Implantation

<h3>Introduction</h3> The use of total artificial heart (TAH) implantation remains of limited use in the United States for patients with biventricular heart failure. One subgroup of patients that have been supported by TAH include patients with pulmonary hypertension that are not candidates for combined heart lung transplantation. These patients are difficult to manage after TAH implantation, as right heart catheterization cannot be performed to guide post surgical therapy. <h3>Case Report</h3> GF is a 49 year old male with ischemic cardiomyopathy on a home milrinone infusion with a left ventricular thrombus, pulmonary embolism, and pulmonary sarcoidosis. He presented with shortness of breath and fatigue. Right heart catheterization demonstrated severely decreased cardiac index (1.59L/min/m2 on thermodilution and 1.68 L/min/m2 on Fick) and severe pulmonary hypertension (transpulmonary gradient 36 mmHg, pulmonary vascular resistance 10.6 Woods Units, pulmonary artery (PA) pulsatility index 1.88). Intra-aortic balloon pump was placed for support and a PA catheter was left in place for continuous hemodynamic monitoring. He continued to decline and required escalation to extracorporeal membrane oxygenation support. He was listed for a heart transplant, but due to persistent severe pulmonary hypertension and new onset bacteremia he was made inactive and the decision was made to pursue alternative mechanical support with a TAH. Since right heart catheterization cannot be performed on patients with a TAH, a pulmonary artery sensor was placed in the left pulmonary artery one day prior to TAH implantation. Postoperatively, the TAH functioned well and the PA pressures were monitored easily with a bedside sensor. Initially, PA pressures ranged from 61-70/36-47 mmHg, but with medical optimization they improved to 37-48/20-27 mmHg by postoperative week 7 and he was relisted for transplant. <h3>Summary</h3> We identified a novel use for a pulmonary artery pressure sensor in a total artificial heart patient to help guide post implantation strategies. Our patient successfully had decreased pulmonary artery pressures and advanced to heart transplant listing.

Anticoagulation in syncardia total artificial heart recipients: anti-factor Xa or activated partial thromboplastin time?

Although the activated partial thromboplastin time (aPTT) has historically been the method of choice for anticoagulation monitoring in patients undergoing mechanical circulatory support with intravenous unfractionated heparin, it is being progressively superseded by the anti-factor Xa (anti-Xa) method. A retrospective single-arm, single-centre analysis of 20 patients who underwent total artificial heart implantation entailed simultaneous determinations of aPTT and anti-Xa. Agreement between these parameters was assessed using the Bland–Altman method. Despite a positive correlation between aPTT and anti-Xa, normal target ranges were poorly aligned: from 5th to 30th postoperative day, for anti-Xa values of 0.2 and 0.4 U/ml corresponding aPTT values were 52.1 and 65.2 s, 7.9 and 14.8 lower than predicted values, respectively. This was not associated with thromboembolic sequalae. It was not possible to demonstrate a significant relationship between the predictor variables (postoperative day; white blood cell count; C-reactive protein concentration; alanine transaminase and alkaline phosphatase level; bilirubin; haemoglobin; albumin and total protein concentration) and the agreement between aPTT and anti-Xa levels. In summary, when anti-Xa levels were used to guide anticoagulation therapy, corresponding aPTT levels were low with respect to target range. Methodology applied in this study is generalizable to other forms of mechanical circulatory support.

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 includedin 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+CD45dim (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 upregulatedat T1 are CD45dim clusters, confirming our results. In conclusion, using a flow cytometry approach, we demonstrated in A-TAH-transplanted patients a significant mobilization of Lin-CD34+CD45dim 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+CD45dim 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.

Ethical Issues in the Deactivation of Total Artificial Heart Support – A Systematic Review

"Introduction: In the context of a relatively constant heart donation rate, the effort to satisfy the needs, has led to the development of mechanical devices that can replace the cardiac function. Estimating an annual potential of 100,000 artificial heart implants in the United States alone, there is an increased interest in these devices, which is why it is appropriate to explore the situations where its inactivation may be ethically appropriate. Method: We performed a systematic review, which includes all the studies regarding the dilemma of artificial hearts inactivation from the beginning until 2020, published in PubMed, Embase and Scopus. The searched keywords were “totally artificial heart and ethics”; the duplicate studies and those referring to other cardiac support devices were excluded. Results: Following the selection, 12 articles were included in the review. The conflict between the principle of discontinuity and the prohibition generated by the indispensability of the artificial heart was emphasized. The decision to inactivate the support dependent on the patient’s declared level of happiness or clinical evolution over time was reviewed. The dilemma of self-inactivation of artificial cardiac support as suicide versus the acceptance of death caused by the underlying heart condition, as well as the impact of total removal of the native heart were included in the ethical analysis. Conclusions: Requests for withdrawal of TAH support are not uncommon among patients, their discontinuation being ethically acceptable when it does not serve the patient’s interests, even though they may still be capable to prolong their life. "

Temporary Diverting End-Colostomy in Critically Ill Children with Severe Perianal Wound Infection.

Broad and deep perianal wounds are challenging in both adult and pediatric ICUs. These wounds, if contaminated with gastrointestinal flora, can cause invasive sepsis and death, and recovery can be prolonged. Controlling the source of infection without diverting stool from the perianal region is complicated. The option of protective colostomy is not well-known among pediatric critical care specialists, but it can help patients survive extremely complicated critical care management. These authors present three critically ill children who required temporary protective colostomy for perianal wounds because of various clinical conditions. Two patients were treated for meningococcemia, and the other had a total artificial heart implantation for dilated cardiomyopathy. There was extensive and profound tissue loss in the perianal region in the patients with meningococcemia, and the patient with cardiomyopathy had a large pressure injury. Timely, transient, protective colostomy was beneficial in these cases and facilitated the recovery of the perianal wounds. Temporary diverting colostomy should be considered as early as possible to prevent fecal transmission and accelerate perianal wound healing in children unresponsive to local debridement and critical care.

Impact of extra-corporeal life support (ECLS) cannulation strategy on outcome after durable mechanical circulation support system implantation on behalf of durable MCS after ECLS Study Group.

The literature on outcomes of patients requiring durable mechanical circulatory support (MCS) after extra-corporeal life support (ECLS) is limited. The aim of this study was to investigate the impact of preoperative ECLS cannulation on postoperative outcome after durable MCS implantation. The durable MCS after ECLS registry is a multicenter retrospective study that gathered data on consecutive patients who underwent durable MCS implantation after ECLS between January 2010 and August 2018 in eleven high volume European centers. Patients who underwent the implantation of total artificial heart, pulsatile pumps, or first-generation pumps after ECLS were excluded from the analysis. The remaining patients were divided into two groups; central ECLS group (cECLS) and peripheral ECLS group (pECLS). A 1:1 propensity score analysis was performed to identify two matched groups. The outcome of these two groups was compared. A total of 531 durable MCS after ECLS were implanted during this period. The ECLS cannulation site was peripheral in 87% (n=462) and central in 13% (n=69) of the patients. After excluding pulsatile pumps and total artificial heart patients, a total of 494 patients remained (pECLS =434 patients, cECLS =60 patients). A 1:1 propensity score analysis resulted in 2 matched groups (each 55 patients) with median age of 54 years (48-60 years) in cECLS group and 54 years (43-60 years) in pECLS group. HeartWare HVAD (Medtronic, Minneapolis, MN) was implanted in the majority of the patients (cECLS =71% vs. pECLS =76%, P=0.67). All postoperative morbidities were comparable between the groups. The thirty-day, one year and long-term survival was comparable between the groups (P=0.73). The cannulation strategy of ECLS appears to have no impact on the post-operative outcome after durable MCS implantation.

A Bridged Approach to Heart Transplantation Using ECMO and Total Artificial Heart Implantation

Purpose The rapid increase of the use of extracorporeal membrane oxygenation (ECMO) as a direct bridge to heart transplantation (HT) raises concerns. The objective of this study is to describe the outcomes after HT using a bridge-to-bridge strategy with a sequence of ECMO support followed by temporary total artificial heart (t-TAH) implantation. Methods A retrospective, multicentric analysis of 54 patients who underwent t-TAH (SynCardia) implantation following the use of an ECMO for cardiogenic shock was performed (ECMO-t-TAH group). A control group of 163 patients who underwent t-TAH implantation as a direct bridge to transplantation (t-TAH group) was used to assess the impact of this strategy. Results Fifty-four patients, averaging 47±13 years old underwent implantation of a t-TAH after 5.3±3.4 days of ECMO perfusion for cardiogenic shock. In the ECMO-t-TAH group, 20 patients (20/54,37%) died after t-TAH implantation and 57 patients (57/163,35%) died in the t-TAH group (p=0.4968). Overall, 32 patients (32/54, 59%) underwent heart transplantation in the ECMO-t-TAH group, compared to 106 patients (106/163, 65%) in the t-TAH group (p=0.4449). No significant difference in survival was observed at 6 months, 1 and 3 years after heart transplant (ECMO-t-TAH group: 94%, 87%, and 80% vs. 87%, 83%, and 76% in the t-TAH group, respectively). Deterioration of liver function tests under t-TAH was associated with increased mortality before heart transplant in both groups. Conclusion The present series suggests that sequential bridging from ECMO to t-TAH followed by heart transplantation is a viable alternative for a group of highly selected patients.