Interrupted Time Series Analysis of Donor Heart Use Before and After the 2018 UNOS Heart Allocation Policy Change.

BACKGROUND: Donor heart scarcity remains the fundamental barrier to increased transplant access. We examined whether 2018 United Network for Organ Sharing (UNOS) policy changes have had an impact on donor heart acceptance rates. METHODS AND RESULTS: We performed an interrupted time series analysis in UNOS to evaluate for abrupt changes in donor heart-acceptance rates associated with the new policy. All adult donor offers were evaluated between 2015 and 2021 (n = 66,654 donors). Donor volumes and transplants increased during this period, but the donor acceptance rate declined significantly from 31% in quarter 3 of 2018 to 26% acceptance in quarter 3 of 2021 (slope change -0.4% per quarter; P < 0.001). We identified 2 trends associated with this decline: (1) a growing number of donors with high-risk features, and (2) decreased acceptance of donors with certain high-risk features in the new allocation system. CONCLUSIONS: Heart transplant volumes have increased in recent years as a result of increased donor volumes, but donor heart acceptance rates began decreasing under the current allocation system. Changes in the donor pool and acceptance patterns for certain donor-risk features may explain this shift and warrant further evaluation to maximize donor heart use.

Heart waitlist survival in adults with an intra-aortic balloon pump relative to other Status 2, Status 1, and inotrope Status 3 patients.

BACKGROUND: Intra-aortic balloon pump (IABP) utilization has significantly outpaced other Status 2 eligibility criteria for heart transplant. The risk of waitlist mortality of IABP-supported patients relative to other Status 2 listed patients has not been described. METHODS: We performed a retrospective analysis of all adult patients listed Status 2 for heart transplantation under the current U.S. allocation policy, using data from the United Network for Organ Sharing. Patients listed status 1 and status 3 for high-dose inotropes were included for reference. Mortality and waitlist decompensation were modeled as a function of time-varying status in cause-specific Cox survival models. RESULTS: We identified 3638 Status 2 listings, of whom 1676 (46%) were Status 2 due to IABP. Relative to patients supported with IABP, status 2 patients with ventricular tachycardia/fibrillation [VT/VF] (HR 4.0, p < .001), right-or-biventricular assist device configurations (HR 2.3, p = .002), or temporary surgical left ventricular assist devices [LVAD] (HR 2.6, p = .003) had greater risk of waitlist mortality and decompensation. Other Status 2 subgroups had mortality comparable to IABP Status 2. Risk of waitlist mortality and decompensation for IABP Status 2 was similar to Status 3 patients listed for high-dose inotropes (HR 1.2, p = .27) and lower than Status 1 patients (HR 0.7, p = .002). CONCLUSIONS: Waitlist mortality varies significantly by Status 2 eligibility criteria and is highest among patients listed for VT/VF, right-or-biVAD configurations, or temporary surgical LVADs. IABP-supported patients were among those with the lowest Status 2 waitlist mortality risk and comparable to Status 3 inotrope-supported patients.