Considerations and experience driving expansion of combined heart-liver transplantation

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.