Observational Study on the Prognostic Relevance of Supratentorial Superficial Siderosis in Patients With Suspected Cerebral Amyloid Angiopathy

Non-traumatic cortical superficial siderosis (cSS) is a common finding in patients with cerebral amyloid angiopathy (CAA) and can be its sole imaging sign. The clinical features and course as well as the prognostic significance of cSS in CAA patients remain unclear. In a retrospective study we have previously shown that cSS might be an important predictor or warning sign for future intracranial hemorrhage. However, prospective data are missing.

The Superficial Siderosis in Patients with suspected Cerebral Amyloid Angiopathy (SuSPect-CAA) study is designed as a prospective observational multi-centre cohort study. Primary objective of the study is to evaluate if cSS is a predictor for future stroke and mortality (primary endpoint: combined rate of stroke and death after 36 months). Secondary objectives of the study include 1) to evaluate if cSS represents a marker of future intracranial haemorrhage, especially at the site of initial siderosis, 2) to describe the clinical presentation and course of cSS, 3) to assess to associated imaging findings, 4) to determine the differential diagnoses of cSS.

All subjects presenting to the respective neurological centers (out- or inpatient treatment with neuroimaging) will be screened. The study population will consist of two patient groups: 1) Patients meeting the modified Boston criteria for probable or possible CAA, i. e. patients with SS +/- lobar intracerebral hemorrhage or microbleeds in cortico-subcortical localization and absence of other cause of hemorrhage than CAA will be assigned to the study group. 2) Patients meeting the classic Boston criteria for possible or probable CAA but without any SS will be assigned to the control group. A total of 100 patients per group will be enrolled. Baseline and follow-up assessment at 6, 12, 24, and 36 months will be performed by visits in the respective neurological outpatient clinic including a structured interview and neurological exam, neuropsychological tests, EEG and MRI.