Brain Hemorrhage and Functional Outcome in Stroke Patients With CAA Features on Pre-thrombolysis MRI Treated With Intravenous Thrombolysis (Thrombolysis in CAA) ( Thromb in CAA )

Background: In stroke patients treated with intravenous thrombolysis (IVT), presence and high number of strictly lobar cerebral microbleeds (compatible with cerebral amyloid angiopathy, CAA) seems to be associated with increased risk of hemorrhagic transformation, symptomatic hemorrhagic transformation, remote hemorrhage, and poor functional outcome. Some of these reported CAA patients with cerebral microbleeds also had chronic lobar intracerebral haemorrhage. Few data is available on IVT-treated CAA patients showing cortical superficial siderosis. There are no reports studying factors associated with brain hemorrhagic complication or functional outcome inside a group of IVT-treated CAA patients. Our aim was to evaluate brain hemorrhagic complications on 24h-CT and functional outcome after IVT in stroke patients with CAA features on pre-IVT MRI. Methods: In our stroke center, IVT decision in patients with CAA MRI features is left at the discretion of the treating physician. We retrospectively screened pre-IVT imaging of 959 consecutive IVT-treated stroke patients (between January 2015 and July 2022) without ongoing anticoagulation therapy for probable CAA MRI features defined by modified Boston criteria. After exclusion of 119 patients with lacking MRI (n=47), with MRI showing motion artefacts (n=49) or with alternative chronic brain hemorrhage cause on MRI (n=23), 15 IVT-treated patients with probable CAA on pre-IVT MRI were identified. In these 15 patients, clinical, biological and MRI characteristics were compared between patients with vs. without post-IVT hemorrhage and between patients with poor (MRS 3-6) vs. good (MRS 0-2) functional outcome at discharge.