EXPLANATION


The first combined heart-liver transplantation (CHLT) was performed in 1984 and is now becoming an increasingly common procedure. The indications and outcomes of 369 CHLT recipients (from 1989 to 2020) listed in the United Network for Organ Sharing (UNOS) registry were recently reviewed by Alexopoulos and colleagues. In the era from 1989 to 2010, the most common cardiac indication/diagnosis was restrictive/infiltrative cardiomyopathy secondary to diseases such as amyloidosis or hemochromatosis. In the era from 2011 to 2020, congenital heart disease was the most common cardiac diagnosis, accounting for 30.9% of CHLT recipients followed by restrictive/infiltrative cardiomyopathy in 26.8% and dilated cardiomyopathy in 21.1%. The most common liver diagnosis in current era of CHLT recipients was cardiac cirrhosis (40.4%).


As the population of patients with congenital heart disease surviving into adulthood has grown, there has been a corresponding rise in the prevalence of liver disease among children with single-ventricle physiology palliated with the Fontan. Liver dysfunction in Fontan patients is believed to be caused by the following two mechanisms: 1) Central hepatic vein and sinusoid dilation due to elevated central venous pressure and, 2) reduced hepatic perfusion secondary to low cardiac output. This results in a redistribution of oxygenated blood to periportal hepatocytes with subsequent atrophy, necrosis, and fibrosis of centrilobular hepatocytes, leading to cirrhosis and regenerative nodules. This heterogenous pattern is present in Fontan patients, particularly ten years post-Fontan-completion. Interestingly, neither invasive hemodynamic measurements nor laboratory abnormalities seem to directly correlate with the severity of fibrosis. Moreover, though portal hypertension develops over time, varices are less prevalent as there is already significant systemic venous hypertension. There is no clear consensus regarding criteria and timing for liver transplant evaluation in Fontan patients, nor which patients would benefit from CHLT. However, a recent scientific statement by the American Heart Association has proposed an algorithm for evaluation of liver disease in potential heart transplant candidates.


While still uncommon overall, the number of CHLTs performed in North America has increased significantly in the last decade. Survival outcomes of CHLT for the overall cohort of 369 patients in the most recent analysis by Alexopoulos were 86.8%, 80.1%, and 77.9% at one, three, and five years respectively. In a multivariable regression analysis, recipient diabetes at listing, CHLT between 1989-2000 compared with 2011-2020, a transplant sequence of heart-after-liver versus liver-after-heart, and lower donor left ventricular ejection fraction were associated with increased mortality after CHLT. Concurrent heart and liver transplant also appears to be associated with improved outcomes, which is thought to be related to the ability of the liver to clear donor-specific HLA class I antibodies.


REFERENCES


Alexopoulos SP, Wu WK, Ziogas IA, et al. Adult Combined Heart-Liver Transplantation: The United States Experience. Transpl Int .2022;35:10036. doi: 10.3389/ti.2021.10036


Tracy KM, Matsuoka LK, Alexopoulos SP. Update on combined heart and liver transplantation: evolving patient selection, improving outcomes, and outstanding questions. Curr Opin Organ Transplant .2023;28(2):104-109. doi: 10.1097/MOT.0000000000001041


Kittleson MM, Sharma K, Brennan DC et al. Dual-Organ Transplantation: Indications, Evaluation, and Outcomes for Heart-Kidney and Heart-Liver Transplantation: A Scientific Statement From the American Heart Association. Circulation .2023;148:622–636. doi:10.1161/CIR.0000000000001155


Ortega-Legaspi JM, Hoteit M, Wald J. Immune benefit of combined heart and liver transplantation. Curr Opin Organ Transplant. 2020;25(5):513-518. doi:10.1097/MOT.0000000000000801


Emamaullee J, Zaidi AN, Schiano T, et al. Fontan-Associated Liver Disease: Screening, Management, and Transplant Considerations. Circulation. 2020;142(6):591-604. doi: 10.1161/CIRCULATIONAHA.120.045597