Background: Patients with restrictive cardiomyopathy (RCM) and hypertrophic cardiomyopathy (HCM) generally are considered poor candidates for mechanical circulatory support devices (MCSDs) and often not able to be bridged mechanically to heart transplantation. This study characterized MCSD utilization and transplant waitlist outcomes in patients with RCM/HCM under the current allocation system and discusses changes in the era of the new donor allocation system.

Methods and Results: Patients waitlisted from 2006 to 2016 in the United Network for Organ Sharing registry were stratified by RCM/HCM versus other diagnoses. MCSD utilization and waitlist duration were analyzed by propensity score models. Waitlist outcomes were assessed by cumulative incidence functions with competing events. Predictors of waitlist mortality or delisting for worsening status in patients with RCM/HCM were identified by proportional hazards model. Of 30 608 patients on the waitlist, 5.1% had RCM/HCM. Patients with RCM/HCM had 31 fewer waitlist days (P<0.01) and were ≈26% less likely to receive MCSD (P<0.01). Cumulative incidence of waitlist mortality was similar between cohorts; however, patients with RCM/HCM had higher incidence of heart transplantation. Predictors of waitlist mortality or delisting for worsening status in patients with RCM/HCM without MCSD support included estimated glomerular filtration rate <60 mL/min per 1.73 m², pulmonary capillary wedge pressure >20 mm Hg, inotrope use, and subjective frailty.

Conclusions: Patients with RCM/HCM are less likely to receive MCSD but have similar waitlist mortality and slightly higher incidence of transplantation compared with other patients. The United Network for Organ Sharing RCM/HCM risk model can help identify patients who are at high risk for clinical deterioration and in need of expedited heart transplantation.

背景：患有限制性心肌病（RCM）和肥厚型心肌病（HCM）的患者通常被认为是机械循环支持设备（MCSD）的较差候选人，并且通常不能机械桥接到心脏移植。这项研究的特点是在当前分配制度下，RCM / HCM患者的MCSD利用率和移植候补名单结果，并讨论了新的捐助者分配制度时代的变化。

方法和结果： 2006年至2016年在美国器官共享网络登记系统中候诊的患者通过RCM / HCM与其他诊断进行分层。通过倾向评分模型分析MCSD的利用率和候补名单的持续时间。通过竞争事件的累积发生率函数评估候补结果。通过比例风险模型确定了RCM / HCM患者的候补死亡率或退役状态恶化的预测指标。在候补名单上的30608名患者中，有5.1％的患者患有RCM / HCM。RCM / HCM患者的等待日数减少了31天（P <0.01），并且接受MCSD的可能性降低了约26％（P<0.01）。队列之间的等待列表死亡率累积发生率相似；然而，RCM / HCM患者的心脏移植发生率更高。没有MCSD支持的RCM / HCM患者的等待名单死亡率或因状态恶化而退役的预测因素包括估计的肾小球滤过率<60 mL / min / 1.73 m ²，肺毛细血管楔压> 20 mm Hg，正性肌力药物使用和主观虚弱。

结论：与其他患者相比，RCM / HCM患者接受MCSD的可能性较小，但候诊者死亡率相似，移植发生率略高。器官共享联合网络RCM / HCM风险模型可以帮助确定临床恶化风险高且需要快速心脏移植的患者。