Reduced Post-transplant Survival in Patients Bridged with durable LVADs following the 2018 US Heart Allocation Policy Change: OPTN/ UNOS Registry Analysis.

Abstract

Purpose: In 2018, the US implemented heart allocation changes to address evolving trends in waiting list mortality. This study examines the impact of the allocation changes on post-transplant survival in patients bridged with durable left ventricular assist devices (LVAD) compared to non-LVAD heart transplant recipients.

Methods: We used the OPTN/UNOS registry to identify adult (≥18 years), first-time, heart-only transplant recipients from 2014-2023. Recipients were categorized by date of transplant into PRE- (1/1/14-17/10/18) and POST (18/10/18-6/10/23) groups and LVAD status at transplant (LVAD vs non-LVAD) to form four analytic groups. Survival outcomes were analyzed using the Kaplan-Meier method. Multivariable Cox regression was used to estimate adjusted associations with post-transplant mortality.

Results: A total of 23,221 HT recipients were included: 11,273 in the PRE (3,542 with LVAD and 7,731 without LVAD) and 11,948 in the POST (3,145 with LVAD and 8,803 without LVAD) era. Compared to PRE, the POST patients were younger (53.8, 52.8 vs 54.0, 54.2 years, p < 0.001), and had better renal function (1.2, 1.2 creatinine vs 1.3, 1.3, p < 0.001). The proportion of patients with LVAD at HT decreased from 31.4% in PRE to 26.3% in POST era (p < 0.001). POST mean waiting times were significantly reduced in non-LVAD recipients (251 to 83 days, 67.1% reduction, p < 0.001) and less so in bridged LVAD recipients (259 to 145 days, 44.0% reduction, p < 0.001). In the POST era, the acuity of LVAD candidates at transplant was higher -the proportion of LVAD patients with < 50 % Karnofsky score was 36 % PRE vs 53.7 % POST (p < 0.0001) and the proportion of LVAD patients on inotropes was 8.1% PRE vs 20.6% POST (p < 0.0001). One-year post-transplant survival of patients bridged with LVAD was 91.2% PRE and 89.3% POST, p<0.0001, and this difference increased further at 3 years - 85.10% PRE to 80.0% POST (p < 0.0001, Table 2). Meanwhile, 1-year survival in patients without LVAD was nominally similar PRE and POST - 91.70% vs 92.0% (p < 0.001), and there was a smaller difference at 3-years - 86.2% PRE vs 83.5% POST, p < 0.0001. Multivariable Cox regression showed that post-policy change, LVAD at transplant was independently associated with increased mortality (HR 1.26, 95% CI 1.12-1.43, p < 0.001).

Conclusions: The 2018 heart allocation policy revision was effective in improving access to transplant for the most acutely ill patients and reducing waitlist mortality. However, the reduction of wait times was not realized to the same extent in LVAD-bridged patients, who also have a signal for higher post-transplant mortality in the current era. Our data provide insights into approaches that may mitigate this excess risk and ensure equitable outcomes for the increasingly complex population of patients bridged to transplant with durable LVADs.