Bridge-to-transplant temporary mechanical circulatory support and risk of allosensitization.

INTRODUCTION: Since the 2018 change in the US adult heart allocation policy, more patients are bridged-to-transplant on temporary mechanical circulatory support (tMCS). Previous studies indicate that durable left ventricular assist devices (LVAD) may lead to allosensitization. The goal of this study was to assess whether tMCS implantation is associated with changes in sensitization. METHODS: We included patients evaluated for heart transplants between 2015 and 2022 who had alloantibody measured before and after MCS implantation. Allosensitization was defined as development of new alloantibodies after tMCS implant. RESULTS: A total of 41 patients received tMCS before transplant. Nine (22.0%) patients developed alloantibodies following tMCS implantation: 3 (12.0%) in the intra-aortic balloon pump group (n = 25), 2 (28.6%) in the microaxial percutaneous LVAD group (n = 7), and 4 (44.4%) in the veno-arterial extra-corporeal membrane oxygenation group (n = 9)-p = .039. Sensitized patients were younger (44.7 ± 11.6 years vs. 54.3 ± 12.5 years, p = .044), were more likely to be sensitized at baseline - 3 of 9 (33.3%) compared to 2 out of 32 (6.3%) (p = .028) and received more transfusions with red blood cells (6 (66.6%) vs. 8 (25%), p = .02) and platelets (6 (66.6%) vs. 5 (15.6%), p = .002). There was no significant difference in tMCS median duration of support (4 [3,15] days vs. 8.5 [5,14.5] days, p = .57). Importantly, out of the 11 patients who received a durable LVAD after tMCS, 5 (45.5%) became sensitized, compared to 4 out of 30 patients (13.3%) who only had tMCS-p = .028. CONCLUSIONS: Our findings suggest that patients bridged-to-transplant with tMCS, without significant blood product transfusions and a subsequent durable LVAD implant, have a low risk of allosensitization. Further studies are needed to confirm our findings and determine whether risk of sensitization varies by type of tMCS and duration of support.

Medical decisions in organ donors and heart transplant candidates with history of COVID-19 infection: An international practice survey.

BACKGROUND: A growing proportion of transplant donors and recipients have a history of COVID-19 infection. This study sought to characterize clinical practice after recipient or donor COVID-19 infection. METHODS: An online survey was distributed to heart transplant clinicians through a professional society message board and social media. Responses were collected between September 29 and November 5, 2021. RESULTS: There were 222 health care professionals (68% transplant cardiologists, 22% transplant surgeons, 10% other) across diverse geographic regions who completed the survey. While there was significant variation in donor acceptance, as it relates to past and current COVID-19 infection, the respondents were fairly cautious: 28% would not typically accept a donor with a history of COVID-19 regardless of the infection course and > 80% would not accept donors who had evidence of myocardial dysfunction during past COVID-19 infection, or who died of COVID-19 or its complications. The timing of candidate reactivation on the waiting list after COVID-19 infection also varied and often diverged from scenarios addressed by social guidelines. Eighty-one percent of the respondents felt COVID-19 vaccine should be mandatory before transplant, but this rate varied by geographic region. CONCLUSION: Our results reflect evolving experience of the heart transplant field at a time of lack of high-quality evidence. In the absence of longer-term outcome data for donors and transplant candidates with history of COVID-19 infection, clinicians remain cautious; however, this approach will likely need to be refined as an increasing proportion of the population will continue to be infected with COVID-19.