Abstract 89: Incidence and Characteristics of Hemorrhagic Stroke Among Post-STOP Participants

Abstract

Introduction: The Stroke Prevention Trial in Sickle Cell Anemia (STOP) changed standards of care for stroke screening and treatment of high-risk children with sickle cell anemia (SCA), reducing the risk of ischemic stroke. However, the incidence of hemorrhagic stroke in young patients with SCA in the post-STOP era remains poorly characterized. Methods: The Post-STOP multicenter cohort study collected follow-up data from prior participants (all with SCA) of the STOP or STOP II clinical trials. From 01/2012 – 05/2014, medical records analysts abstracted clinical, imaging and laboratory data collected after the STOP studies ended at 19 of the 26 original sites. Two stroke neurologists reviewed data to confirm hemorrhagic stroke, defined as primary spontaneous intracerebral, subarachnoid or intraventricular hemorrhage; we excluded traumatic hemorrhage or hemorrhagic conversion of ischemic infarcts. Incidence rates among those with no prior hemorrhagic stroke at the start of Post-STOP were calculated using survival analysis techniques. Results: Follow-up data were collected from 2,851 of 3,835 participants participated in the STOP trials. Patients (51% male) were a median age of 10.4 years (interquartile range [IQR] 6.8-14.1) at the start of Post-STOP. Over a median of 10.3 (IQR 7.3-11.4) years of follow-up, 35 patients with hemorrhagic stroke were identified (Table 1). The incidence rate was 63 per 100,000 person-years overall (95% CI 45-87). Stratified by age, the incidence rate per 100,00 person-years was 50 (95% CI 34-75) for children less than 18 years old and 134 (95% CI 74-243) for adults over the age of 50. Conclusion: In our cohort, we observed that the risk of hemorrhagic stroke in patients with SCA rises as patients age, most sharply after the first decade of life. Structural vascular abnormalities such as moyamoya syndrome and aneurysms are common etiologies for hemorrhage and screening may be warranted.