Flow diversion for intracranial aneurysms in patients with sickle cell disease

Introduction Sickle cell disease (SCD) confers a three-to fivefold increase in the prevalence of intracranial aneurysms (IA). Flow diversion (FD) requires mandatory dual antiplatelet therapy (DAPT), yet perioperative transfusion to reduce hemoglobin S (HbS) risks delayed hemolytic transfusion reaction (DHTR). No guidelines address this conflict between DHTR-associated coagulopathy and mandatory DAPT. We report the largest FD series in SCD. Methods Retrospective single-center case series of SCD patients undergoing FD for IA (2017 to 2026). Of 12 SCD patients treated for aneurysms, seven received FD and comprised the analytic cohort. Results Seven patients (5 HbSS, 2 HbS/β 0 -thalassemia; median age 38; 71% female) harbored 29 aneurysms; 12 were treated with FD across 8 procedures using 15 devices. HbS <30% was achieved in 3 of 7 (43%); one patient underwent FD at HbS 78.5% due to alloimmunization. Clopidogrel hyporesponsiveness was identified in 2 of 4 TEG-tested patients (50%). Procedure-related mortality was 14% (1/7): fatal DHTR with DIC on postoperative day 8, the first reported DHTR-DAPT collision. Procedure-related morbidity included one intraoperative thrombus and one vasospasm episode, both resolved without sequelae (2/8 procedures, 25%). Additional events included asymptomatic in-stent stenosis and delayed stroke from SCD vasculopathy. At last follow-up, 5 of 6 survivors maintained mRS 0 to 1. Discussion and Conclusion FD is technically feasible in SCD, but the 14% procedure-related mortality from a fatal DHTR exposes the unresolved conflict between transfusion-associated hyperhemolysis and mandatory DAPT. CYP2C19-mediated clopidogrel resistance and alloimmunization pose additional challenges that require predefined protocols and prospective multicenter registries.