Utility of OPO Procurement Surgeons in Reducing Discards of Marginal Liver Allografts

In this issue of Transplantation, Shubin et al present an interesting analysis evaluating the benefits of organ procurement organization (OPO) surgeon being present at liver procurements. The authors reviewed over 1500 cases from their OPO.¹ Overall, the discard rate and outcomes were similar between procurements with an “OPO surgeon” and those with only an “institutional surgeon” in attendance. However, when a propensity analysis with donor quality variables was applied, the liver discard rate was cut in half when an OPO surgeon was present. With a discard rate of nearly 10%, including 30% from donors after circulatory death (DCD), it presents an interesting adjunctive strategy to increase the donor pool.

Sending a team to often remote locations is taxing to personnel and resource utilization and has tangible risks to team members.² Allowing OPOs or “local” surgeons to “take a look” and export the liver if satisfactory saves significant energy and expense if the liver is declined. The new UNOS acuity circle allocation system introduced in 2020 has necessitated more distant travel. Many centers have different opinions about using “local” or OPO recovery. Some aggressive centers prefer to send a team to evaluate marginal donors and relegate “standard criteria” donors to a “local” recovery surgeon. Trust and relationships between recipient institutions, OPOs, and “local” surgeons are important and may result in relaxation of some of these practices and facilitate the center’s comfort with the concept of OPO or local recovery. In addition, high quality pictures, video, and ability to view biopsies in conjunction with good communications reduce the fear of the unknown.³ Each center and even individual surgeons have a different tolerance for the “unknown” factor that is inherent to delegating the procurement to someone who is not from their “team.” A trusted local or OPO surgeon can change this equation and increase efficiency as well as enhance the potential for backup placement should the need arise. The acuity circle system increased use of “local recovery” at most centers, which makes this article particularly timely. It will be interesting to see how these trends evolve under this new allocation rubric since the dates of this study predate the policy change.

In the United States, DCDs are a relevant conundrum as many centers insist on performing their own recovery with a particular protocol or technique.⁴ These cases have the highest likelihood of discard and failure to progress (up to 30%) and thus are the “riskiest” in terms of resource utilization. In addition, emerging novel technology using ex vivo liver machine perfusion and normothermic regional perfusion for DCD is a consideration for how we evolve as a community and develop best practices for liver procurement.^5–10 Liver machine perfusion may facilitate more aggressive use of “marginal” livers. An OPO surgeon may be called upon to cannulate and facilitate placement of a liver on an ex vivo perfusion device. In the past several years, there has been great progress in development of viability markers in both NMP and HMP to help predict which livers will function well.¹¹ These evolving practices may be another benefit that an OPO surgeon can bring to the equation.

In this paper, the OPO surgeons appear to be the employees of the OPO. However, many OPOs contract local transplant surgeons to be present on behalf of the OPO for “local” recovery requests or to join the procurement even if a liver procurement team comes from another DSA. It is unclear if the authors would consider this scenario as equivalent and thus whether their results can be extrapolated. In both scenarios there are benefits such as reallocation if the primary team declines the liver early in the process requiring a delayed cross clamp. Likewise, an OPO or local surgeon may be helpful to recover the kidneys and research organs, which again allows the outside team to depart more expediently, thereby reducing cold ischemia time and improving logistics for sicker recipients. Individual OPOs and transplant centers may have differing opinions and motivations regarding “best practices.” The ASTS leadership has interest in related topics and recently has commissioned a collaborative entitled the Organ Recovery Collaborative Network taskforce that engages a broad group of stakeholders and is designed to enhance local recovery, reduce team travel, and standardize best practices for organ recovery and transport. Although we support the idea of the OPO having major input on the implementation of best practices, this may create some friction in terms of whether liver recovery surgeons should be OPO employees or transplant surgeons from local programs or some combination of both. We believe an important driver is the increasing regulatory pressures on OPOs to increase organ utilization, which is definitely an important contributor to the growing practice of OPO-based surgeons. In addition, variations in characteristics and geographic size of OPOs are likely to have a significant impact on these decisions. Complex compensation issues also typically arise in these situations, which are important to consider but beyond the scope of this commentary.

We should also bear in mind the study design limitations to avoid drawing broad conclusions that may complicate practice. As a nonrandomized retrospective database type analysis there are many opportunities for bias. In this study, logistics such as recipient team preference and surgeon availability were clearly factors that limit the generalizability of the results. The presence of the OPO surgeon did not affect clinical outcomes; rather, it improves logistics and resulted in reduced discard rate only in a subgroup of what the authors have arbitrarily classified as “marginal” allografts. Although in general, we agree in principle with the author’s criteria, it is not entirely clear at which point in the analysis the propensity scores and definition of what is a “marginal” liver were defined. The inability to fully stratify groups for the entire study period to determine at which cases, there was a recipient center surgeon present in addition to the OPO surgeon. The authors do note that in the later 2 y of the study period, there was an additional “institutional surgeon” in 45% of cases; this further complicates the interpretation and take-home points of the study. Clearly this study was a first step in attempting to identify benefits of having OPO surgeons routinely participating in organ procurements. This seems like a logical recommendation particularly as liver ex vivo perfusion technology becomes more widespread. Further updated analyses from other OPOs will be helpful in confirming this observation and guiding the evolution of best practices for organ procurement.