To the Editor:

The transplant community is experiencing an expansion of ex vivo machine perfusion protocols for deceased donor organs with potential gains in organ utilization and the promise of improving graft function following transplantation.^1-3 Many of these perfusion protocols are performed by non-Organ Procurement Organization (OPO) entities, such as transplant centers or for-profit companies, which represents a fundamental shift in how ex vivo perfusion is managed. In the United States, OPOs have the responsibility to coordinate the process of organ donation, from recovery until final acceptance for transplantation. These responsibilities can be challenging for an OPO when re-allocation of an ex vivo perfused device is necessary; the OPO is not involved in the management or monitoring of the organ, yet now has the responsibility of consolidating relevant information regarding organ quality and transfer the organ to a back-up center willing to accept an ex vivo organ managed by another center.

For example, once a liver is accepted by the transplant center for a primary patient and the transplant center indicates that ex vivo machine preservation will be initiated, there may be circumstances where the intended recipient is not deemed suitable for transplantation because of a medical condition identified after perfusion is initiated or when the criteria of suitability of the organ as stipulated by the ex vivo protocol is not ultimately fulfilled. Re-allocation in these circumstances should follow the match-run to ensure the integrity of the allocation system is not detoured by ex vivo protocols.

In the short term, it is possible that back-up centers will not accept ex vivo perfused organs as a matter of clinical practicality or unfamiliarity with other centers' protocols. Additionally, it is unclear how a back-up center can thoroughly consent their patient under the time constraints of an organ offer if the ex vivo perfusion is under a different center's research protocol. This may lead to “open” organ offers for any patients at centers managing their own perfusion devices rather than following the patient-specific match-run, giving rise to equity concerns for patients listed at centers not comfortable with ex vivo preservation. Organ allocation policies are designed to be patient-specific not center-specific and optimizing equity along with increased utilization of organs is critical.^{4, 5}

To mitigate deviation from the match-run at re-allocation that could foster center versus patient-specific organ offers, we urge OPO's and transplant centers to take the following actionable steps: OPOs and centers should develop guidelines for when ex vivo perfusion is undertaken independent of the OPO's purview and which should include identifying back-up patients prior to initiation of ex vivo perfusion, standardized perfusion run data sheets where an OPO can upload this information into DonorNet, and standardized steps to remove organs from perfusion devices and package them to back-up centers. In the longer term, the transplant community—either through society or United Network for Organ Sharing led workgroups—should develop consensus and best practice guidelines which will support the growth of ex vivo perfusion while ensuring equity for all listed patients.

致编辑：

移植界正在经历针对已故供体器官的离体机器灌注方案的扩展，这可能会提高器官的利用率，并有望改善移植后的移植物功能。^1-3其中许多灌注方案是由非器官采购组织 (OPO) 实体执行的，例如移植中心或营利性公司，这代表了离体灌注管理方式的根本转变。在美国，OPO 有责任协调器官捐献的过程，从恢复到最终接受移植。当需要重新分配离体灌注设备时，这些职责对 OPO 来说可能具有挑战性；OPO 不参与器官的管理或监测，但现在有责任整合有关器官质量的相关信息，并将器官转移到愿意接受由另一个中心管理的离体器官的后备中心。

例如，一旦移植中心接受了原发患者的肝脏，并且移植中心表示将开始离体机器保存，则可能会出现预期接受者因确定的医疗条件而被认为不适合移植的情况开始灌注后或最终未达到离体方案规定的器官适用性标准时。在这些情况下重新分配应遵循匹配运行，以确保分配系统的完整性不会被离体协议绕道。

在短期内，由于临床实用性或不熟悉其他中心的协议，后备中心可能不会接受离体灌注器官。此外，如果离体灌注是根据不同中心的研究方案进行的，尚不清楚后备中心如何在器官提供的时间限制下完全同意他们的患者。这可能会导致在管理自己的灌注设备的中心向任何患者提供“开放”器官，而不是遵循特定患者的匹配运行，从而引起中心列出的对离体保存不满意的患者的公平性担忧。器官分配政策旨在针对特定患者而非特定中心，优化公平性以及增加器官利用率至关重要。^{4, 5}

为了减少重新分配时与匹配运行的偏差，这可能会促进中心与患者特定器官的供应，我们敦促 OPO 和移植中心采取以下可操作的步骤： OPO 和中心应制定独立进行离体灌注的指南OPO 的职权范围，其中应包括在开始离体灌注之前识别备用患者、标准化灌注运行数据表，OPO 可以将此信息上传到 DonorNet，以及从灌注设备中取出器官并将其包装回原位的标准化步骤-向上中心。从长远来看，