ABO-Incompatible Platelet Transfusion Is Associated with Ischemic Lesions on Brain MRI in Patients with Intracerebral Hemorrhage

Background: We have identified that major ABO-incompatible platelet transfusions are associated with poor intracerebral hemorrhage (ICH) outcomes. The underlying drivers for the relationship of these incompatible platelet units on outcome are unknown, yet do not appear to be related to impaired hemostasis. Conversely, ICH patients are known to encounter remote, “silent” ischemic lesions, thought to be from microthrombosis, during their hospitalization. Though these ischemic lesions are well known to associate with poor ICH outcomes, risk factors for its formation are unknown. We explored whether major ABO-incompatible platelet transfusions are associated with acute ischemic lesions on brain MRI during an ICH hospitalization.

Methods: Consecutive spontaneous ICH patients enrolled into a single-center, prospective cohort study between 2009 and 2018 were assessed. Patients who received a single platelet transfusion within 24 hours of ICH admission and had a brain MRI during the hospitalization were included in the analysis. Major ABO incompatible platelet transfusion (vs minor mismatch/identical) was defined as the exposure. Presence of remote ischemic lesions, defined as diffusion restriction >10 mm away from the hematoma detected on brain MRI, was the outcome. Regression models were used to assess relationships between major ABO-incompatible platelet unit exposure and acute ischemic brain lesions, adjusting for time from ICH onset to MRI or ICH severity.

Results: We identified 40 ICH patients receiving an acute platelet transfusion and having a brain MRI performed during the ICH hospitalization. The mean age was 67.1 (SD 14.1), 37.5% were female, and 20% received a major ABO incompatible platelet unit. Patients receiving a major incompatible platelet unit were more likely to encounter ischemic lesions (62.5% vs 21.9%). We also identified an association of major ABO-incompatible platelets units with acute ischemic brain lesions in our regression models after adjusting for time from ICH symptom onset to MRI (OR 5.45, 95%CI 1.01-29.30, p=0.048) and ICH severity (OR 9.15, 95%CI 1.37-62.67, p=0.024). Additional sensitivity analysis adjusting for patient blood type did not alter this relationship (OR 17.1, 95%CI 1.34-217.9, p = 0.029).

Conclusions: Among ICH patients receiving acute platelet transfusions and MRI neuroimaging, major ABO incompatible units were associated with remote ischemic lesions on brain MRI. Further work is needed to address the generalizability of our data and to clarify relationships of platelet unit characteristics, cerebral microthrombosis, and clinical outcomes after ICH.