Status, Indications, and Use of Cardiac Replacement Therapy in the Era of Multimodal Mechanical Approaches to Circulatory Support: A Scoping Review

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

BACKGROUND

The SynCardia® temporary total artificial heart (TAH) serves as a mechanical circulatory support device for patients suffering from irreversible biventricular failure.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Novel Therapies for Right Ventricular Failure

PURPOSE OF REVIEW

Traditionally viewed as a passive player in circulation, the right ventricle (RV) has become a pivotal force in hemodynamics. RV failure (RVF) is a recognized complication of primary cardiac and pulmonary vascular disorders and is associated with a poor prognosis. Unlike treatments for left ventricular failure (LVF), strategies such as adrenoceptor signaling inhibition and renin-angiotensin system modulation have shown limited success in RVF. This review aims to reassure about the progress in RVF treatment by exploring the potential of contemporary therapies for heart failure, including angiotensin receptor and neprilysin inhibitors, sodium-glucose co-transporter 2 inhibitors, and soluble guanylate cyclase stimulators, which may be beneficial for treating RV failure, particularly when associated with left heart failure. Additionally, it examines novel therapies currently in the pipeline.

RECENT FINDINGS

Over the past decade, a new wave of RVF therapies has emerged, both pharmacological and device-centered. Novel pharmacological interventions targeting metabolism, calcium homeostasis, oxidative stress, extracellular matrix remodeling, endothelial function, and inflammation have shown significant promise in preclinical studies. There is also a burgeoning interest in the potential of epigenetic modifications as therapeutic targets for RVF. Undoubtedly, a deeper understanding of the mechanisms underlying RV failure, both with and without pulmonary hypertension, is urgently needed. This knowledge is not just a theoretical pursuit, but a crucial step that could lead to the development of pharmacological and cell-based therapeutic options that directly target the RV and pulmonary vasculature, aligning with the principles of precision medicine.

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.

Postoperative management and nursing care after implantation of a total artificial heart: Scoping review

INTRODUCTION

End-stage heart failure (HF) is a condition whose only successful long-term treatment, with a survival of more than 10 years, is heart transplantation. However, limited organ availability and the progressive increase in the number of patients with advanced HF have served as an impetus for the development of implantable mechanical assistive devices.

AIM

To provide an overview of postoperative management and nursing care after the implementation of a Total Artificial Heart (TAH).

METHODS

A scoping review was carried out by consulting the PUBMED, CINAHL, and COCHRANE databases. From all the documents located, information was extracted on the date of publication, country of publication, type of study, and results of interest to answer the research question. In addition, the degree of recommendation was identified.

RESULTS

Twenty-three documents were included in the scoping review. Results were classified in relation to: 1) description of the CAT SynCardia®; 2) nursing care in the immediate postoperative period (management of the device and management of hematological, infectious, nephrological, nutritional complications, related to immobilization, sleep-rest disturbances, psychological disorders, and patient and family education); and 3) follow-up at home.

CONCLUSIONS

The complexity of implantation of the TAH, the multiple related complications that can arise during this process, both in the immediate post-operative and late, require a standardised and multidisciplinary management. The absence of standardised protocols raises the need for future studies to measure the effectiveness of care in patients with TAH. A multidisciplinary approach is crucial. Nurses must acquire autonomy and involvement in decision-making and develop competencies to address the patient's and family's physiological and psychosocial needs.

Current and future options for adult biventricular assistance: a review of literature

In cardiogenic shock various short-term mechanical assistances may be employed, including an Extra Corporeal Membrane Oxygenator and other non-dischargeable devices. Once hemodynamic stabilization is achieved and the patient evolves towards a persisting biventricular dysfunction or an underlying long-standing end-stage disease is present, aside from Orthotopic Heart Transplantation, a limited number of long-term therapeutic options may be offered. So far, only the Syncardia Total Artificial Heart and the Berlin Heart EXCOR (which is not approved for adult use in the United States unlike in Europe) are available for extensive implantation. In addition to this, the strategy providing two continuous-flow Left Ventricular Assist Devices is still off-label despite its widespread use. Nevertheless, every solution ensures at best a 70% survival rate (reflecting both the severity of the condition and the limits of mechanical support) with patients suffering from heavy complications and a poor quality of life. The aim of the present paper is to summarize the features, implantation techniques, and results of current devices used for adult Biventricular Mechanical Circulatory Support, as well as a glance to future options.

Total artificial heart as a bridge to transplantation

PURPOSE OF REVIEW

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.

RECENT FINDINGS

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.

SUMMARY

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.

"It Works." Every heart transplant program should have one

The total artificial heart (TAH) provides full biventricular cardiac replacement, pulsatile perfusion at flows of 7-9 L/min at low filling pressures. This allows organs that are failing to recover and for the potential cardiac recipient to become a better transplant candidate. Postimplant patients are mobile and able to go through physical rehabilitation in a hospital or at home. The risks are acceptable as shown by the authors. TAH use in more transplant centers could save lives in many transplant candidates.

Cardiac Surgery in Advanced Heart Failure

Mechanical circulatory support and heart transplantation are established surgical options for treatment of advanced heart failure. Since the prevalence of advanced heart failure is progressively increasing, there is a clear need to treat more patients with mechanical circulatory support and to increase the number of heart transplantations. This narrative review summarizes recent progress in surgical treatment options of advanced heart failure and proposes an algorithm for treatment of the advanced heart failure patient at >65 years of age.

Modern Approaches in Cardiovascular Disease Therapeutics: From Molecular Genetics to Tissue Engineering

Cardiovascular disease (CVD) currently represents one of the leading causes of death worldwide. It is estimated that more than 17.9 million people die each year due to CVD manifestations. Often, occlusion or stenosis of the vascular network occurs, either in large- or small-diameter blood vessels. Moreover, the obstruction of small vessels such as the coronary arteries may be related to more pronounced events, which can be life-threatening. The gold standard procedure utilizes the transplantation of secondary vessels or the use of synthetic vascular grafts. However, significant adverse reactions have accompanied the use of the above grafts. Therefore, modern therapeutic strategies must be evaluated for better disease administration. In the context of alternative therapies, advanced tissue-engineering approaches including the decellularization procedure and the 3D additive bioprinting methods, have been proposed. In this way the availability of bioengineered vascular grafts will be increased, covering the great demand that exists globally. In this Special Issue of Bioengineering, we tried to highlight the modern approaches which are focused on CVD therapeutics. This issue includes articles related to the efficient development of vascular grafts, 3D printing approaches and suitable atherosclerosis models.

Improved Repopulation Efficacy of Decellularized Small Diameter Vascular Grafts Utilizing the Cord Blood Platelet Lysate

BACKGROUND

The development of functional bioengineered small-diameter vascular grafts (SDVGs), represents a major challenge of tissue engineering. This study aimed to evaluate the repopulation efficacy of biological vessels, utilizing the cord blood platelet lysate (CBPL).

METHODS

Human umbilical arteries (hUAs, n = 10) were submitted to decellularization. Then, an evaluation of decellularized hUAs, involving histological, biochemical and biomechanical analysis, was performed. Wharton's Jelly (WJ) Mesenchymal Stromal Cells (MSCs) were isolated and characterized for their properties. Then, WJ-MSCs (1.5 × 10⁶ cells) were seeded on decellularized hUAs (n = 5) and cultivated with (Group A) or without the presence of the CBPL, (Group B) for 30 days. Histological analysis involving immunohistochemistry (against Ki67, for determination of cell proliferation) and indirect immunofluorescence (against activated MAP kinase, additional marker for cell growth and proliferation) was performed.

RESULTS

The decellularized hUAs retained their initial vessel's properties, in terms of key-specific proteins, the biochemical and biomechanical characteristics were preserved. The evaluation of the repopulation process indicated a more uniform distribution of WJ-MSCs in group A compared to group B. The repopulated vascular grafts of group B were characterized by greater Ki67 and MAP kinase expression compared to group A.

CONCLUSION

The results of this study indicated that the CBPL may improve the repopulation efficacy, thus bringing the biological SDVGs one step closer to clinical application.

Surgical Management of Heart Failure

Optimal management of heart failure is collaborative, with the involvement of specialist heart failure physicians, nurses, interventionalists, and surgeons. In addition to medical optimisation and cardiac resynchronisation therapy, surgery plays a valuable role in many patients. We herein study the evidence and the role of surgical intervention in functional mitral regurgitation, coronary revascularisation in ischaemic cardiomyopathy, and surgical ventricular reconstruction. Additionally, we describe techniques of temporary and durable mechanical circulatory support, with their relative advantages and disadvantages, and applications. Finally, we describe the history and nomenclature around heart transplants, their indications, techniques, present-day outcomes, complications, and new developments in the field.

Future Perspectives in Small-Diameter Vascular Graft Engineering

The increased demands of small-diameter vascular grafts (SDVGs) globally has forced the scientific society to explore alternative strategies utilizing the tissue engineering approaches. Cardiovascular disease (CVD) comprises one of the most lethal groups of non-communicable disorders worldwide. It has been estimated that in Europe, the healthcare cost for the administration of CVD is more than 169 billion €. Common manifestations involve the narrowing or occlusion of blood vessels. The replacement of damaged vessels with autologous grafts represents one of the applied therapeutic approaches in CVD. However, significant drawbacks are accompanying the above procedure; therefore, the exploration of alternative vessel sources must be performed. Engineered SDVGs can be produced through the utilization of non-degradable/degradable and naturally derived materials. Decellularized vessels represent also an alternative valuable source for the development of SDVGs. In this review, a great number of SDVG engineering approaches will be highlighted. Importantly, the state-of-the-art methodologies, which are currently employed, will be comprehensively presented. A discussion summarizing the key marks and the future perspectives of SDVG engineering will be included in this review. Taking into consideration the increased number of patients with CVD, SDVG engineering may assist significantly in cardiovascular reconstructive surgery and, therefore, the overall improvement of patients' life.

Outcomes after heart transplantation and total artificial heart implantation: A multicenter study

BACKGROUND

We sought to assess the outcomes after heart transplantation (HT) of patients supported with a temporary total artificial heart (t-TAH) as a bridge to transplantation in high-volume centers.

METHODS

A retrospective analysis of 217 consecutive patients who underwent t-TAH (SynCardia Systems, Tucson, Arizona) implantation between January 2014 and May 2019 in 6 high-volume North American centers was performed. End points included survival and adverse events after t-TAH and HT.

RESULTS

The mean age of patients was 49 ± 12 years, and heart failure etiologies were non-ischemic dilated cardiomyopathy (36%), ischemic (25%), restrictive (12%), and cardiac graft failure (9%). A total of 101 (48%) patients had Interagency Registry for Mechanically Assisted Circulatory Support patient profile 1, and 65 (31%) had Interagency Registry for Mechanically Assisted Circulatory Support patient profile 2. At the end of the study period, 138 of 217 (63.5%) patients had undergone HT, and 75 (34.5%) patients died before HT. The mean time between t-TAH implantation and HT averaged 181 ± 179 days (range: 0-849) and the mean follow-up after HT was 35 ± 25 months. The overall survival in the entire cohort was 75%, 64%, and 58% at 1, 2, and 5 years, respectively. Post-transplant survival was 88%, 84%, 79%, and 74% at 6 months, 1 year, 2 years, and 5 years, respectively. Among the 32 patients (23%) who died after HT, the main causes of death were chronic allograft vasculopathy (25%), multiorgan failure (21.8%), sepsis (15.6%), and stroke (9%).

CONCLUSION

In this multicenter study, almost two thirds of patients implanted with a t-TAH could be transplanted. The overall and post-transplantation survival after t-TAH was satisfactory in these critically ill patients.

Long-term biventricular circulatory support with POLVAD-MEV paracorporeal pulsatile pumps. Single-centre experience

Introduction

Severe heart failure decompensation requires circulatory mechanical support in emergency situations. Polish paracorporeal pulsatile pumps, POLVAD-MEV, are designed for biventricular end-stage heart dysfunction.

Aim

To evaluate long-term POLVAD-MEV therapy by multiple pump exchange in patients on a transplant list.

Material and methods

There were 3 patients in INTERMACS level 1 referred for emergency POLVAD-MED implantation due to acute heart failure deterioration. The paracorporeal pulsatile mechanical support was applied due to severe biventricular dysfunction.

Results

They were supported by paracorporeal biventricular POLVAD-MEV pumps for 438, 473 and 394 days until heart transplantation. During the hospitalisation the pumps required multiple pumps exchanges within 29 ±10 (4–49) day intervals.

Conclusions

POLVAD-MEV paracorporeal pulsatile pumps present a safe option for long-term circulatory support in a selected group of patients. Therapy requires pump exchange but enables survival while awaiting a heart transplant.