Department of Surgery, NYU Grossman School of Medicine, NYU Langone Health, New York, New York, USA.
Chronic Disease Research Group, Hennepin Healthcare Research Institute, Minneapolis, Minnesota, USA.
Clin Transplant. 2023 Sep;37(9):e15017. doi: 10.1111/ctr.15017. Epub 2023 May 19.
The Organ Procurement and Transplantation Network (OPTN) is eliminating geographic boundaries in liver allocation, in favor of continuous distribution. Continuous distribution allocates organs via a composite allocation score (CAS): a weighted sum of attributes like medical urgency, candidate biology, and placement efficiency. The opportunity this change represents, to include new variables and features for prioritizing candidates, will require lengthy and contentious discussions to establish community consensus. Continuous distribution could instead be implemented rapidly by computationally translating the allocation priorities for pediatric, status 1, and O/B blood type liver candidates that are presently implemented via geographic boundaries into points and weights in a CAS.
Using simulation with optimization, we designed a CAS that is minimally disruptive to existing prioritizations, and that eliminates geographic boundaries and minimizes waitlist deaths without harming vulnerable populations.
Compared with Acuity Circles (AC) in a 3-year simulation, our optimized CAS decreased deaths from 7771.2 to 7678.8 while decreasing average (272.66 NM vs. 264.30 NM) and median (201.14 NM vs. 186.49 NM) travel distances. Our CAS increased travel only for high MELD and status 1 candidates (423.24 NM vs. 298.74 NM), and reduced travel for other candidates (198.98 NM vs. 250.09 NM); overall travel burden decreased.
Our CAS reduced waitlist deaths by sending livers for high-MELD and status 1 candidates farther, while keeping livers for lower MELD candidates nearby. This advanced computational method can be applied again after wider discussions of adding new priorities conclude; our method designs score weightings to achieve any specified feasible allocation outcomes.
器官获取与移植网络（OPTN）正在取消肝脏分配的地理边界，转而采用连续分配。连续分配通过复合分配评分（CAS）分配器官：对医疗紧急程度、候选者生物学和安置效率等属性的加权总和。这种变化代表了一个机会，可以纳入新的变量和功能来优先考虑候选者，这将需要进行冗长而有争议的讨论，以建立社区共识。连续分配也可以通过计算将目前通过地理边界实施的儿科、1 级状态和 O/B 血型肝脏候选者的分配优先级转换为 CAS 中的分数和权重来快速实施。
我们使用模拟和优化设计了一个 CAS，该 CAS 对现有优先级的干扰最小，消除了地理边界，并最大限度地减少了等待名单上的死亡人数，而不会损害弱势群体。
与 3 年模拟中的敏锐度循环（AC）相比，我们的优化 CAS 将死亡人数从 7771.2 人减少到 7678.8 人，同时降低了平均（272.66 NM 与 264.30 NM）和中位数（201.14 NM 与 186.49 NM）的旅行距离。我们的 CAS 仅增加了高 MELD 和 1 级状态候选者的旅行距离（423.24 NM 与 298.74 NM），并减少了其他候选者的旅行距离（198.98 NM 与 250.09 NM）；整体旅行负担减轻。
我们的 CAS 通过将肝脏分配给高 MELD 和 1 级状态的候选者更远的地方，同时将低 MELD 候选者的肝脏保留在附近，从而减少了等待名单上的死亡人数。在更广泛地讨论添加新优先级后，可以再次应用这种先进的计算方法；我们的方法设计评分权重以实现任何指定的可行分配结果。
