Collaborative Research on Kidney Exchange

肾脏交换的合作研究

• 批准号: 1061889
• 负责人: Itai Ashlagi
• 金额: $ 29.34万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1061889&HistoricalAwards=false
• 关键词: Collaborative; Research; Kidney; Exchange

The need for kidney exchange arises when someone who wishes to donate a kidney to a particular recipient is incompatible with that recipient. Two or more such incompatible patient-donor pairs can sometimes both receive transplants through an exchange,when the donor in one pair is compatible with the recipient in the other (or in cycles involving more incompatible pairs). Stemming in part from previously funded NSF research, organized kidney exchanges, such as the New England Program for Kidney Exchange (NEPKE) havebecome active in the United States, and now multiple regional kidney exchanges exist and are growing, and a national exchange is being contemplated (following the passage of the Charlie W.Norwood Living Organ Donation Act in 2007). The growth of kidney exchange to include many hospitals has raised new practical and theoretical questions and this award funds research that develops new methods in mechanism design to answer these questions.The first issue is incentives. When kidney exchange programs started, the first models incorporatedpatient-donor pairs and their surgeons. However, the success of regional exchanges has demonstrated that transplant centers (hospitals) must also be included in the strategic analysis. Transplant centers deal with multiple patient-donor pairs, and their strategy sets include the possibility of withholding some pairs from the kidney exchange and revealing only those pairs that the hospital cannot match on its own. The team has observed exactly this in practice, and preliminary research results suggest that there is no way to get hospitals to reveal all their pairs while still using a efficient kidney exchange matching algorithm. Additional research explores the incentive properties of matching mechanisms in large populations. The PIs seek to demonstrate that existing mechanisms do not have good incentive properties even in large populations, but that alternative mechanisms can be designed that would have both good incentives and good efficiency properties when there are many patient-donor pairs in the pool, as would be the case in a successful national exchange.The second part of the project concerns efficiency. The PIs adapt the classical (undirected) random graph results of Erdos and Rényi (1959, 1966) to graphs that model the compatibility between patient-donor pairs, and use these to explore the behavior of large kidney exchanges, with many pairs. The first part of this work will look at general populations of patients and donors, and the second part will consider the differently structured large graphs that result when there is a large population of extremely sensitized patients who have low probability of finding a donor. (This will involve modeling the compatibility graph in more detail; instead of one node for each patient and her donors, there will have to be separate nodes for patients and donors, since the connectedness of donors will be unaffected by the patient?s low probability offinding a compatible kidney, so that, once such a kidney is found, the pair will be well connected.) We will also consider different kidney exchange strategies, including the management of possibly long chains of donations.Broader Impacts: There are over 80,000 patients on the waiting list for cadaver kidneys in the U.S. In 2009, 33,678 patients were added to the waiting list,10,441 transplants of cadaver kidneys were performed, 4,456 patients died while on the waiting list, and more than 1,941 others were removed from the list as ?Too Sick to Transplant?. There were also 6,387 transplants of kidneys from living donors in the US. There is a severe shortage of kidneys for transplant. Kidney exchange is in recent years the still small but fastest growing source of live kidney donors. Improvements in the methods used to match donors and recipients will save lives. The PIs will collaborate with transplant centers and regional alliances to take the newly developed methods into application.

当希望将肾脏捐献给特定接受者的人与该接受者不相容时，两个或更多这样的不相容的患者-捐赠者对有时可以通过交换来接受移植，而一对中的捐赠者是相容的。与接受者在另一个（或在循环中更不相容的配对）部分源于先前涉及资助的 NSF 研究，有组织的肾脏交换，例如新英格兰肾脏交换计划（NEPKE）已在美国变得活跃。多个地区肾脏交换已经存在并且正在增长，并且正在考虑进行全国性交换（继 2007 年《查理·W·诺伍德活体器官捐赠法案》通过之后）肾脏交换的发展包括许多医院，这提出了新的实践和理论问题。该奖项资助开发机制设计新方法来回答这些问题的研究。第一个问题是激励措施。当肾脏交换计划启动时，第一个模型纳入了患者-捐赠者对及其外科医生。然而，区域交换的成功证明了移植。中心（医院）也必须纳入战略分析中，涉及多个患者-捐赠者对，他们的战略设置包括从肾脏交换中保留某些对的可能性，并仅显示医院自身无法匹配的那些对。该团队在实践中准确地观察到了这一点，初步研究结果表明，在仍然使用有效的肾脏交换匹配算法的同时，无法让医院透露所有配对。其他研究探索了大人群中匹配机制的激励特性。 PI 试图证明现有的即使在人口众多的情况下，这种机制也没有良好的激励特性，但是当储备库中有许多患者-捐助者对时，可以设计替代机制，既具有良好的激励作用，又具有良好的效率特性，就像一个成功的国家该项目的第二部分涉及效率。PI 将 Erdos 和 Rényi (1959, 1966) 的经典（无向）随机图结果改编为模拟患者-捐赠者对之间的兼容性的图，并使用这些来探索。这项工作的第一部分将着眼于患者和捐赠者的一般人群，第二部分将考虑当存在大量极度敏感的患者时所产生的不同结构的大型图表。找到捐赠者的可能性较低（这将涉及更详细地对兼容性图进行建模；不是为每个患者及其捐赠者一个节点，而是必须为患者和捐赠者分别设置节点，因为捐赠者的连通性会降低）。不受患者影响（找到兼容肾脏的可能性很低，因此，一旦找到这样的肾脏，这对肾脏就会很好地连接。）我们还将考虑不同的肾脏交换策略，包括管理可能的长捐赠链。更广泛的影响：有在美国，有超过 80,000 名患者在等待尸体肾脏的名单上。2009 年，等待名单上新增了 33,678 名患者，进行了 10,441 例尸体肾脏移植手术， 4,456 名患者在等待名单上死亡，另有超过 1,941 名患者因“病重而无法移植”而被从名单中删除。美国还有 6,387 例来自活体捐赠者的肾脏移植，可供移植的肾脏严重短缺。近年来，肾脏交换仍然是规模较小但增长最快的活体肾脏捐赠来源，PI 将与移植中心合作，改进用于匹配捐赠者和接受者的方法。区域联盟将新开发的方法付诸应用。