Hemorrhagic transformation after intracranial stenting for acute stroke: Clinical insights from the RESISTANT registry

Background and aim: Acute intracranial stenting is increasingly used as a rescue strategy during endovascular treatment for large vessel occlusion strokes. Limited data exist regarding the risk, clinical relevance, and optimal management of hemorrhagic transformation (HT) in this context. We aimed to evaluate the incidence, predictors, outcomes, and post-interventional antiplatelet management of HT in an international multicentric registry. Methods: We analyzed data from the RESISTANT registry, including patients who underwent emergent intracranial stenting for acute stroke between 2016 and 2023. Two complementary analyses were performed: (1) characterization of HT subtypes and associated outcomes (NIHSS at discharge, mortality, and mRS at discharge and 90 days) and (2) evaluation of antiplatelet management after Heidelberg class-1 HT detection and its impact on stent occlusion, hemorrhage progression, in-hospital mortality, and 90-day mRS. Results: Among 809 patients included, 177 (22%) experienced HT, of which 63 (8%) were symptomatic intracranial hemorrhage. Parenchymal hematomas (PH-1 and PH-2) and HI-2 were associated with worse functional outcomes and higher mortality. In the post-HT management cohort (n = 117), use of a high-intensity antiplatelet regimen (dual oral antiplatelet or any intravenous agent) was associated with lower risk of stent occlusion (adjusted risk ratio (aOR) = 0.21 [0.05–0.86]) and in-hospital mortality (aOR = 0.08 [0.01–0.50]) without increased hemorrhagic progression (0.52 [0.09–3.07]). Conclusion: HT remains a relevant complication after emergent intracranial stenting, particularly in patients with parenchymal hematoma. High-intensity antiplatelet therapy appears safe in select HT subtypes and was linked to reduced occlusion and mortality.