Organ transplantation in Fontan patients—beware of false promises

With great interest, we read the recent review article on transplantation in Fontan patients by Tolani et al.¹ The authors provide a comprehensive overview on the current state of medical knowledge and ongoing debates in this evolving field. In their conclusion section, the authors state that “transplantation (is) increasingly viewed as the final stage of palliation” and that continued innovations are “essential to improve outcomes and equity” in the (transplanted) Fontan population.¹ By using the term “equity” the authors touch upon the ethical dimensions of an increasing number of Fontan patients in need of organ transplantation. While we agree with the authors, that—by sole medical measures—transplantation can justifiably be regarded as the “final stage of palliation” in Fontan patients,1, 2 the real-world situation significantly restricts accessibility to this option in many cases (at least within the Eurotranplant region). In light of the current donor organ scarcity (and omnipresent economic pressure on Western health care systems), we should avoid making false promises, such as the perception of transplantation as a universally available option as 4th or final stage of palliation for all Fontan patients. Especially in the context of prenatal counseling, the general outlook of transplantation as a future option may in fact constitute such a false promise as most likely only a minority of single ventricle patients will finally undergo transplantation.

From epidemiological studies it is estimated that approximately 60-70/million persons with a Fontan circulation live in industrialized countries.³ In Austria, with roughly 9 million inhabitants, this corresponds to approximately 500 Fontan patients (with half of them being of adult age). Under the assumption that all adult Fontan patients will finally experience circulatory failure and, hence, require cardiac transplantation within the next 20 years, this would result in ∼27 heart transplants per year (not including potential pediatric cases of Fontan failure). Although this is only a rough estimation and not every adult Fontan patient eventually undergoes transplantation, the discrepancy between potential organ demand and availability becomes obvious when considering that the total number of heart transplantations performed in Austria ranges between 40 and 70 per year. Of note, in Germany, the situation is comparable, with an estimated total Fontan population of ∼5,000 patients vs ∼ 330 heart transplantations performed annually.

In light of a current waitlist mortality of ∼10%-20% within the Eurotransplant region, an increasing number of transplantations will challenge the principles of allocation equity, which is further aggravated when considering outcome measures. While post-transplant outcomes have significantly improved in Fontan patients and now tend to equal those in other congenital heart disease (CHD, biventricular) post-transplant outcomes, 5-year survival rates are still worse as compared to those of non-CHD cardiac transplant recipients.¹ As also stated by Tolani et al, the recent trend to consider heart transplantation earlier in failing Fontan patients may help improve outcomes, but—on the other hand—further increases the demand for donor organs.¹

The specific situation of Fontan patients with Fontan-associated liver disease listed for combined heart-liver transplantation may further aggravate the potential concerns for distributive justice. Specifically, organs used for multiorgan transplant may be of better quality (younger donor age, better liver function) than those used for single-organ transplantation, and prioritization of 1 organ (heart) over the other (liver) may undermine equity in the allocation process.⁴ However, combined heart-liver transplantation outcomes are not inferior to heart-transplant outcomes in experienced centers and may even hold the potential for superior survival.5, 6, 7

Transplantation in failing Fontan patients may be associated with significant improvements in physical capacity and general health perception and a potential reduction in complications (e.g., arrhythmias, slower progression of liver and/or kidney dysfunction).¹ An increased quality of life would provide further arguments in favor of transplanting Fontan patients; nonetheless, there is a lack of actionable data regarding post-transplant patient improvement beyond survival metrics with modern measures, such as quality-adjusted life years, allowing for a comparison between different transplant cohorts.⁸

In conclusion, the foreseeable increase in demand for organ transplantation in Fontan patients poses significant medical, ethical, and economic challenges to our societies, requiring constant re-evaluations of resources, regulations, and allocation processes in order to ensure equity, societal consensus, and support of those most in need. Our role as caregivers should be to advocate for our patients, while we should also foster medical progress by conducting and promoting research. In the current situation, it is imperative to optimally select transplant candidates, which includes timely evaluation for transplantation in order to improve outcomes. On the other hand, while organ availability and allocation equity is a concern globally, a reticence to transplant higher-risk patients out of concern for damaging program metrics clearly represents a potential barrier for certain Fontan patients.

Thus, we should undertake every possible measure to increase donor availability. Further research is required in order to improve survival and outcomes in all Fontan patients and should encompass durable implantable mechanical circulatory support systems as potential destination therapy for failing Fontan circulations (in contrast to currently available external bridge-to-transplantation devices).9, 10 Importantly, none of the single ventricle patients chose to be born with their condition, and transplantation represents a pivotal treatment option in selected Fontan patients, who all deserve optimal management, societal support, and allocation of scarce resources. However, we should avoid expectations of organ allocation that our current systems cannot necessarily support.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.