Abstract and Introduction
Objectives: The goal of this study was to describe outcomes of patients with bridge to heart transplantation (BTT) after changes were made to the donor heart allocation system.
Background: Left ventricular assist devices (LVADs) have been used as a BTT. On October 18, 2018, the donor heart allocation system in the United States was updated.
Methods: This study identified adults in the United Network for Organ Sharing database with durable, continuous-flow LVAD at listing or implanted while listed between April 2017 and April 2020. Baseline recipient and donor characteristics, waitlist survival, and post-transplantation outcomes were compared pre- and post-allocation system change.
Results: A total of 1,794 patients met inclusion criteria: 983 in the pre-change period and 814 afterward. The number of patients listed with LVAD decreased nationally over time from 102 in April 2017 to 12 in April 2020 (p < 0.001). The proportion of patients with LVAD at time of transplant decreased from 47% to 14%. Before the change, the majority were Status 1A (75.8%) at transplantation; afterward, most were Status 2/3 (67.8%). Transplantation rates were not different (85.4% vs. 83.6%; p = 0.225), but waitlist time decreased in the post period (82 vs. 65 days; p = 0.004). Donors were more likely to be high risk (39.0% vs. 32.2%; p = 0.005), and both ischemic times and distance traveled increased (3.4 h vs. 3.1 h; p < 0.001; 199 miles vs. 82 miles; p < 0.001). Waitlist survival did not change, but post-transplantation survival was worse in patients with BTT post-change (p < 0.001).
Conclusions: The number of patients with BTT on the transplant list decreased steadily and dramatically after the allocation system change. Although time to transplant decreased, there was an increase in post-transplant mortality. These data suggest that the risks and benefits of LVAD implantation as a BTT have changed under the new allocation system and that the appropriate indication for this treatment strategy warrants a re-evaluation.
For several decades, heart transplantation was the only life-prolonging treatment option for patients with end-stage heart failure. Imbalances between a relatively static donor supply and increasing number of patients in need for transplantation led to increases in waitlist mortality. Furthermore, many patients deteriorated clinically to the point of not being suitable recipients. With improvements in durable left ventricular assist device (LVAD) technology, many of these patients were able to be stabilized en route to eventual cardiac transplantation, resulting in nearly one-half of donor hearts being transplanted into patients on LVAD support in 2018.[1,3] This pattern challenged the donor allocation system and raised questions regarding equity of a system that did not necessarily prioritize or adequately stratify the clinical instability of patients on LVAD support.
In 2018, the Organ Procurement and Transplantation Network (OPTN) allocation system modified adult heart allocation by changing from a 3-tiered system to a 6-tiered system. The intentions were to increase organ availability for patients believed to be the most medically urgent, improve discrimination among listed patients with distinct levels of urgency, reduce waitlist mortality and waitlist time, and address disproportionate organ availability due to the prior geographic sharing. Under the prior system, patients with LVAD were eligible to be listed as Status 1A (the most urgent status) for 30 days or if they were experiencing a life-threatening device complication; otherwise, they were listed Status 1B. The 2018 heart allocation system revision acknowledged the low mortality risk for clinically stable patients with LVAD and developed uniform definitions for LVAD complications to stratify risk more robustly. Under this scheme, stable patients with LVAD are listed as Status 4, with increased urgency afforded to those with life-threatening ventricular arrhythmias (Status 1), nondischargeable patients or those with device failure (Status 2), or those with other device-related complications such as device infection, hemolysis, pump thrombosis, aortic insufficiency, and right heart failure (Status 3). Patients still have access to a 30-day discretionary period at a higher priority (Status 3). Status 1 or 2 patients are, additionally, given preference for organ offers from a wider geographic area (up to 500 miles from the donor location).
The impact of these changes on the use of LVADs in patients awaiting cardiac transplantation are unknown, as are the waitlist times and post-transplantation outcomes. To address these questions, we analyzed the United Network for Organ Sharing (UNOS) database from before and after the implementation of the new adult heart allocation system.
JACC Heart Fail. 2021;9(6):420-429. © 2021 American College of Cardiology Foundation