Increased Prevalence of Stroke After Heart Transplant in the New Allocation System Era.

Background: Temporary mechanical circulatory support (tMCS) use has increased after the 2018 United Network for Organ Sharing (UNOS) heart transplant allocation criteria change. However, tMCS is associated with increased stroke risk and may impact stroke rates after heart transplant. This study sought to determine the impact of the criteria change on posttransplant stroke rates.

Methods: The study included 19,512 patients from the UNOS database who received a heart transplant between October 18, 2014, and October 17, 2022, divided into precriteria change (n = 9768) and postcriteria change (n = 9744) cohorts. The primary outcome was stroke, and secondary outcomes included mortality and adverse events.

Results: At baseline, patients who received a transplant postcriteria change had higher rates of prior stroke (7.6% vs 6.0%, P < .001) and were more likely to be bridged from tMCS. The posttransplant stroke rate was significantly higher in patients who received a transplant after the criteria change compared with before (3.7% vs 3.0%, P = .009). Multivariable logistic regression found that receiving a transplant after the criteria change was an independent risk factor for posttransplant stroke (adjusted odds ratio, 1.208; 95% CI, 1.011-1.443; P = .038). Multivariable Cox analysis of patients in the postcriteria change era showed that posttransplant stroke was independently associated with nearly 6-times greater risk of mortality within 6 months after transplant (adjusted hazard ratio, 5.951; 95% CI, 4.091-8.658; P < .001).

Conclusions: The 2018 donor heart allocation criteria change is associated with a higher risk of posttransplant stroke. Posttransplant stroke increased the risk of mortality by 6-fold during the early posttransplant period.