Lung Retransplantation: Practical and Ethical Considerations Raised by the Hannover Protocol

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Lung transplantation is a resource intensive endeavor requiring extensive skill and coordinated teamwork. Allocation of donor lungs, which represent a very scarce resource, throws ethical issues of social justice into the framework. Because of the gap between patients with end-stage lung disease and the supply of suitable donors, the field of lung transplantation has developed policies which attempt to allocate the supply of lungs with the best total benefit across patients. The Lung Allocation Score, which was developed in the United States and adapted in Europe, represents a utilitarian attempt at maximizing net benefit. One aspect of lung transplantation where the ethics of retransplantation have become challenging is that of retransplantation. Since the 1990s, prominent bioethicists have made the argument that the difference in efficacy between primary transplantation and retransplantation should be the primary driver for policy decisions on when retransplantation should be offered.1 In liver transplantation, where the ethics of retransplantation arguably has the most consensus, there is growing agreement that retransplantation should be limited to patients who have a projected survival at 5 years of greater than 50%.2 No granular policy determinations have emerged from the main lung transplant society, the International Society of Heart and Lung Transplantation (ISHLT). Yet it is noteworthy that the concept of which patients to consider for retransplantation did merit a section in the most recent consensus guidelines from the ISHLT.3
Lung transplant outcomes are tracked in the ISHLT database, and importantly the 1-year survival for retransplantation lags considerably compared with primary transplantation at 69% versus 84%.4 Overall, in the international database, retransplantation represents about 4% of total transplant volume, a small but not insignificant number of transplants. It is this gap in survival between primary and retransplant cases that has created uncertainty about which patients to consider for retransplantation. In this issue of Transplantation, the surgical team from Hannover reports their center experience with retransplantation.5 Dr. Sommer and colleagues report on a protocol-based approach applied to one of the largest transplant programs in the world. At their center, retransplantation accounted for 6.8% of total transplant volume. With over 100 primary and retransplant cases per year, this team has one of the largest experiences with lung transplantation in the world. Here, they report a 1-year survival of 81.6%. What this means is that the Hannover team could approach with retransplantation a survival rate typically observed in primary transplants, thereby removing one of the primary ethical considerations against the practice of retransplantation.
Dr. Sommer and colleagues report on a very deliberate approach to retransplantation of 49 patients. All procedures were bilateral transplants. They used a sternum-sparing anterolateral thoracotomies, in contrast to the more typical clambshell thoracotomy currently used. They attempted to avoid heparin as well as extracorporeal support. Finally, during the operation, they reperfused the first implanted lung for thirty minutes prior to clamping the pulmonary artery on the second lung to decrease the potential for primary graft dysfunction. As a comparison, they assessed outcomes from 39 patients who had undergone retransplant in the 5 years before initiating this Hannover protocol. In that era their 1-year survival was 63.2%. The major unanswerable question is what accounts for the improvement in survival? One possibility is that there was a direct effect of the protocol used. Although it is certainly possible that the operative refinements played some role in their success, other factors are almost certainly driving the results. One major factor is that of patient selection. For example, only 4% of the retransplants performed using their protocol had acute graft failure (compared with 13% in their historic cohort).
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