Considerations and experience driving expansion of combined heart–liver transplantation

Abstract

Purpose of review Heart transplantation concomitant with a liver transplant may be warranted when end-stage heart failure results in irreversible liver failure. Previously reported outcomes have been excellent yet the specific immunoprotective role of the liver allograft is not known. We review the current literature about the immunologic benefit for combined heart and liver transplantation (CHLT). Recent findings The total number of combined heart and liver transplants continues to increase and accounts for approximately 25 cases per year. Familial amyloid polyneuropathy with cardiac cirrhosis is the most common indication for CHLT while adult congenital heart disease (CHD) with associated cirrhosis is increasing in frequency. The majority of recent registry data suggest a statistically equivalent to modestly improved survival advantage for CHLT compared with isolated heart transplantation. Direct mechanisms accounting for this survival advantage are not proven, but combined heart and liver transplants experience lower rates of acute cardiac rejection and cardiac allograft vasculopathy (CAV). Summary Combined heart and liver transplants remain a small percentage of the total heart transplants worldwide, but the majority of recent literature confirms the safety and viability of this option for patients with end-stage heart and liver disease. Equivalent to modestly improved survival outcomes, lower rates of acute cardiac rejection and CAV warrant further investigation into the liver allograft's immunoprotective effect on the transplanted heart. The key mechanisms of tolerogenicity have important implications for surgical technique and immunosuppression requirements. Future directions include development of criteria for heart–liver transplant candidacy and identification of equitable allocation protocols.

Congestive Hepatopathy

“…In FAP, the liver is transplanted to avoid ongoing damage to the cardiac allograft. A consistent observation regardless of the indication is that cardiac dysfunction is the primary driver of combined organ transplant [ 118 , 119 , 120 ]. Until recently, FAP remained the most common indication of CHLT in the US.…”

“…This disproportionate five-fold increase is due to the growing number of the Fontan-palliated population presenting with decompensated heart failure (there are now more adults than children living with congenital heart diseases in the US), but also to organ allocation policy changes giving them priority status and mandating that, in patients with multiorgan transplantation, the second-required organ has to be allocated to the multi-organ candidate from the same donor [ 121 ]. Despite the number of CHLT has increased gradually in the US to approximately 25 cases per year from 2015, CHLT remains a small percentage (<4%) of the total HT worldwide [ 118 ]. In Spain, the first CHLT was performed in 1999, and, as of 2019, only 14 CHLT have been performed in four of the 25 institutions harboring a liver transplant program (data provided by the Organización Nacional de Trasplantes).…”

“…The underlying mechanism of this immune tolerant property of the liver allograft is not well understood. The leading theory is that it may promote clearance of donor-specific antibodies of the recipients [ 118 , 121 ]. The optimal surgical approach and timing of CHLT remain to be defined, and there are no specific surgical recommendations.…”

“…In general, there is no major difference in the surgical techniques with regard to the methods of transplantation for each organ. The most commonly described technique is performing the HT on cardiopulmonary bypass, discontinuing bypass, leaving the chest open, and performing the liver transplant with selective use of venovenous bypass [ 112 , 118 ]. Of note, the number of transplant centers with experience in performing this surgery in any national organ transplant system is small, and among these centers, the number of CHLT performed each year varies greatly.…”

Overview on Cardiac Cirrhosis and Congestive Hepatopathy - A Review

“…The fundamental motivator of mixed organ transplant is cardiac failure, regardless of the rationale. Until recently, FAP was the most common sign of CHLT in the United States [3,[28][29][30].…”