Major ABO-Incompatible Platelet Transfusions Are Associated With Brain Ischemia After Intracerebral Hemorrhage.

Background: Major ABO-incompatible platelet transfusions are associated with poor intracerebral hemorrhage (ICH) outcomes, yet drivers for this relationship remain unclear. Brain magnetic resonance imaging (MRI) ischemic lesions after ICH are neuroimaging biomarkers of secondary brain injury and are associated with poor outcomes. Given that ABO-incompatible platelet transfusions can induce immune complex formation, thrombo-inflammation, and endothelial barrier disruption, factors that could exacerbate cerebral ischemia, we explored whether major ABO-incompatible platelet transfusions are risk factors for ischemic lesions on brain MRI after ICH.

Methods: Adult patients admitted to a tertiary-care academic center between 2009 and 2016 who received a single-platelet transfusion within 24 hours of admission after an ICH, had available donor/recipient ABO data, and brain MRI during the hospitalization were analyzed. Adjusted regression models evaluated relationships between major ABO-incompatible platelet units and MRI ischemic lesions.

Results: A total of 40 patients were included in the study. The mean age was 67.1 (SD, 14.1), and 37.5% were female. Twenty percent of patients received a major ABO-incompatible platelet unit. Major ABO-incompatible platelet transfusions were associated with increased odds of MRI ischemic lesions after adjusting for ICH severity (adjusted odds ratio, 9.2 [95% CI, 1.3-62.7]).

Conclusions: Our exploratory findings suggest that major ABO-incompatible platelet transfusions may contribute to secondary brain injury after ICH. Further work is needed to assess whether avoiding major ABO-incompatible platelet transfusions can prevent secondary brain injury burden and improve ICH outcomes.