Unintended Consequences: The Rise In Dual Organ Heart Transplantation

Heart transplantation is the gold standard therapy for Stage D heart failure since the advent of immunosuppressive agents and improved understanding of the immune system. With growing expertise and experience, more patients are listed - always outstripping the supply of usable donor organs. As a result, allocation systems were created to organize the waitlist with specific prioritizations elucidated by the Final rule in 2000 by the US Department of Health and Human Services including preserving the ability for transplant programs to accept or deny an organ, avoid wasting organs, to promote patient access to organs, not be based on a candidate's place of residence or listing, improve waitlist survival, and be reviewed periodically. The heart allocation system has prioritized getting organs to the sickest patients on the waitlist to reduce waitlist death while not adversely impacting post-transplant outcomes. As a result, our heart candidates are sicker than ever and as a result, concomitant advanced end organ dysfunction is more likely as the disease pathways are often shared, especially with heart and kidney disease and the aging congenital population for heart and liver disease. It is well known that isolated heart transplant in the setting of kidney or liver disfunction has worse outcomes, both in morbidity and mortality. This, combined with growing pressures for maintaining high post-transplant outcomes, has resulted in a rise in heart-kidney and heart-liver listings and transplants, especially over the past decade. While some of the second organs will recover after isolated heart transplant, there are no clear mechanisms to accurately predict such in an individual patient and to be wrong could be devastating for the patient and the program. Until now, there have been no guiding principles of how these patients qualify for the second organ (beyond society guidelines recommending CrCl < 30 mL/min or active clinical cirrhosis) until recently. Prompted by the growing volume of multi-organ transplantation, a new allocation policy has been created to standardize listing criteria for the heart-kidney candidate, going into effect spring 2023 and the criteria for the heart-liver candidate is under development.

This scientific statement summarizes the current implications of advanced kidney or liver disease on heart transplant only outcomes and acknowledges the limitations to pre-transplant evaluations for predicting reversibility of organ dysfunction after cardiac transplant. It must be understood that any guidelines for clinical practice or allocation systems which are based on numbers such as creatine clearance, glomerular filtration rate, cystatin or liver function tests can fluctuate based on the cardiac condition at the moment, and can be modified to promote listing or delisting in many circumstances. Consensus guidelines are the only method currently available to unite the transplant programs under similar "rules of engagement" to provide equitable access to single and multi-organ transplants across the country. Yet these qualifying criteria are just the first step in the process leading to multiorgan transplantation.

In this statement, Kittleson and colleagues acknowledge that transplant center expertise in dual organ transplantation can factor heavily into the decision to list for one heart alone or dual organ, especially the congenital patients who make up a significant portion of heart-liver candidates. Transplant centers must honestly evaluate their internal expertise and processes to tackle multiorgan transplants as the outcomes are worse than heart transplant alone with functional secondary organs. Proper surgical planning between the thoracic and abdominal teams is paramount as significant primary graft dysfunction of the heart will almost certainly prevent implantation of the abdominal organ or markedly impair its chances for successful function. Aggressive strategies to mitigate primary graft dysfunction must also be in place.

This statement also reviews immunosuppressive strategies at the time of transplant to minimize dysfunction of the second organ and ongoing therapies to promote longevity of both organs. This is especially important as there is growing concern that the kidney or liver could have been given to a kidney or liver only recipient with superior outcomes than are currently demonstrated by our heart dual transplant recipients.

As our heart transplant candidates continue to get sicker in an environment of waitlists growing faster than there are donors available, more and more of these patients will need consideration for dual organ, and in some circumstances, triple organ transplantation. As a community, it is imperative that we create universal standards for evaluation and qualification for multiorgan transplants that are based on scientific data and not institutional biases or fear of outcomes. We must understand who we can improve and convert to heart only transplant, best methods for managing the post-heart transplant recipient with compromised end organ function as the new safety net criteria go into effect and who truly requires dual organs for adequate survival. Finally, we must develop an allocation system that is equitable for all patients and acknowledge that without an increase in available donors, we continue to produce a "survival of the fittest" scenario for our patients on the waitlist.