Cortical Superficial Siderosis and Risk of Bleeding after Thrombolysis for Ischemic Stroke

Cortical superficial siderosis (CSS) is a neuroimaging marker of cerebral amyloid angiopathy and has been associated with a high risk for early subsequent major intracranial hemorrhage (ICH). Therefore, many experts recommend withholding of antithrombotic medication to patients with CSS. In this study, we sought to investigate the prevalence of CSS and the associated risk of ICH in the setting of intravenous thrombolysis (IVT) for ischemic stroke.

We retrospectively searched the medical documentation system of our primary and tertiary care university clinic for all patients with ischemic stroke that received IVT from 2009 to December 2014. All available imaging data were reviewed in a standardized manner and blinded to any clinical data for the presence of CSS and ICH. CSS was defined as linear signal loss along the cerebral cortex on gradient echo T2*-weighted sequences. A stroke neurologist, who was blinded to the neuroimaging data, extracted the corresponding clinical data including follow-up information.

We identified 298 patients that received IVT and had undergone brain MRI (mean age 67.6 ± 12.6 years, 59.4% male). Cerebral MRI was performed in 116 patients (38.9%) before and in 182 patients (61.1%) after IVT (median time from stroke symptom onset to MRI: 1 day; range 0-7 days). Only 3 patients (2 females and 1 male aged 90, 76 and 73 years, respectively) had CSS (1%). All of them had a middle cerebral artery (MCA) stroke with a corresponding vessel occlusion. The 76-year-old female patient had extensive CSS and numerous cerebral microbleeds and received another IVT treatment for recurrent MCA stroke 8 months after the first event. After both IVTs, she had clinically asymptomatic small ICH outside the ischemic infarct and distant from CSS. The 2 other patients had only mild to moderate CSS and did not experience any ICH on postthrombolytic imaging.

The prevalence of CSS in a clinical cohort of stroke patients that received IVT was low and thus does not appear to pose a substantial risk for symptomatic ICH although this may occur in individual patients. However, such analysis also needs to be extended to the very old stroke patients in whom IVT is increasingly used.