Cerebral Amyloid Angiopathy–Related Hemorrhage: Interaction of APOE ε2 With Putative Clinical Risk Factors

Abstract

Background and purpose Current evidence suggests that the apolipoprotein E (APOE for gene; apoE for protein) epsilon4 allele predisposes to cerebral amyloid angiopathy (CAA) whereas epsilon2 is associated with CAA-related hemorrhage (CAAH). The clinical risk factors for other forms of intracranial hemorrhage are a less-frequent feature of CAAH. In this study we examined potential clinical risk factors in patients with CAAH and assessed these with respect to APOE genotype. Methods Thirty-six patients were identified with a pathological diagnosis of CAAH. Clinical notes were reviewed to document age of hemorrhage onset, history of dementia, antiplatelet/anticoagulant medication, hypertension, minor head trauma, or transient neurological events. In a review of reported cases of CAAH, the frequency of these clinical features was also recorded. APOE genotypes were determined with use of polymerase chain reaction techniques. Results There were 24 women and 12 men; the mean age was 70.3 years. One third (n=12) had been taking antiplatelet medication, and a similar number were demented. Nine patients were hypertensive, and 4 had a history of recent minor head trauma. The relative frequency of each of these clinical features was similar to that in previous reports. Forty-four percent (16 of 36) possessed an epsilon2 allele. Antiplatelet or anticoagulant medication, hypertension, or minor head trauma were significantly more frequent antecedents of CAAH in epsilon2 carriers than in non-…