BACKGROUND: Temporary mechanical circulatory support (tMCS) usage 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 post-transplant stroke rates. METHODS: The study included 19,512 patients from the UNOS database who received heart transplant between 10/18/2014 to 10/17/2022, divided into pre-criteria change (n=9768) and post-criteria change (n=9744) cohorts. The primary outcome was stroke, and secondary outcomes included mortality and adverse events. RESULTS: At baseline, patients transplanted post-criteria change had higher rates of prior stroke (7.6% vs 6.0%, p<
0.002) and were more likely to be bridged from tMCS. There was a significantly higher post-transplant stroke rate in patients transplanted after the criteria change compared to before (3.7% vs 3.0%, p=0.009). Multivariable logistic regression found that being transplanted after the criteria change was an independent risk factor for post-transplant stroke (aOR [95% CI]: 1.208 [1.011-1.443], p=0.038). Multivariable Cox analysis of patients in the post-criteria change era showed that post-transplant stroke was independently associated with nearly six times greater risk of mortality within 6 months post-transplant (aHR [95% CI]: 5.951 [4.091-8.658], p<
0.002). CONCLUSIONS: The 2018 donor heart allocation criteria change is associated with a higher risk of post-transplant stroke. Post-transplant stroke increased the risk of mortality by six-fold during the early post-transplant period.