Total Artificial Heart, Bridge to Transplant or Destination??

Heart failure is a complex condition, which is rapidly growing with high morbidity and mortality. As per data published by John Wiley & Sons in 2020, globally 64.3 million patients were suffering from heart failure. The U.S. alone accounts for 5.7 million cases and the prevalence of the target disease will increase at a rapid pace to reach 8 million by 2030. Heart transplant is the most trusted treatment for patients suffering from advanced heart failure. However, a significant shortage of organ donors and a long waiting period for the transplantation led to clinicians looking for alternate treatment options. Mechanical circulatory support is a viable option to support patients as a bridge to transplant and destination therapy.?

Univentricular devices such as LVADs and RVADs demonstrate significantly favorable outcomes in patients with single ventricle failure. However, in a subset of patients with biventricular failure, univentricular devices are not sufficient. Furthermore, the incidence of right ventricular failure in post LVAD implantation led to increased morbidity and mortality. It has resulted in the increased demand for biventricular devices including, the total artificial heart. Total Artificial Heart (TAH) is a circulatory device that is designed to replicate the functionality of the natural heart using a pneumatically propelled pulsative device that replaces native arteries and four valves.

"SynCardia Temporary Total Artificial Heart" is the only U.S. FDA-approved TAH as a bridge to transplant. Currently, TAH is approved for the patients who are not the candidates for BiVADs or LVADs along with the following conditions,

• Used only as a bridge to transplant
• The immediate risk of death due to biventricular failure
• Absence of any alternate medical and surgical option
• The patient meets the selection criteria for the heart transplant.
• Presence of adequate space in the patient's chest that will be vacated by the removal of natural ventricles
• No chances of survival without a donor's heart??
• Absence of other critical clinical conditions including but not limited to coagulation disorders, systemic infection & respiratory failure

As per SynCardia Systems, LLC, there have been slightly over 1,700 TAH implants globally. Though the first successful TAH implant was in 1982, these are still the early days for the total artificial heart with its limited usage globally. Factors for this limited usage are stringent conditions associated with the eligibility of TAH, limited (0-2) years of survival after the implantation, high prices of these devices, and the limited number of qualified facilities and surgeons for the transplant.??

The recent approval of CARMAT's total artificial heart for sale in the European Union will reinforce the adoption of these devices among the larger population as a bridge to transplant. Continuing development of novel TAHs by organizations such as Cleveland Clinic, BiVACOR, and few others highlights the possibility of advanced long-term devices. Furthermore, ongoing studies for the usage of TAH as a destination therapy projects bright prospects for patients without a suitable organ donor.