Cerebral Amyloid Angiopathy in Amyloid-Positive Patients from a Memory Clinic Cohort

Background: The overlap between cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD) is frequent and relevant for patients with cognitive impairment. Objective: To assess the role of the diagnosis of CAA on the phenotype of amyloid-beta (A beta) positive patients from a university-hospital memory clinic. Methods: Consecutive patients referred for suspected cognitive impairment, screened for A beta pathological changes in cerebrospinal fluid (CSF), with available MRI and neuropsychological results were included. We determined the association between probable CAA and clinical, neuropsychological (at presentation and after a mean follow-up of 17 months in a sub-sample) and MRI (atrophy, white matter hyperintensities, perivascular spaces) characteristics. Results: Of 218 amyloid-positive patients, 8.3% fulfilled criteria for probable CAA. A multivariable logistic regression showed an independent association of probable CAA with lower A beta(1-42) (adjusted odds ratio [aOR] = 0.94, 95% confidence interval [95%CI] = 0.90-0.98, p = 0.003), and A beta(1-40) (aOR = 0.98, 95%CI=0.97-0.99 p = 0.017) levels in CSF, and presence of severe burden of enlarged perivascular spaces (EPVS) in the centrum semiovale (aOR = 3.67, 95%CI = 1.21-11.15, p = 0.022). Linear mixed-model analysis showed that both groups significantly deteriorated in global clinical severity, executive function and memory. Nevertheless, the presence of probable CAA did not differently affect the rate of cognitive decline. Conclusion: The presence of probable CAA in A beta positive patients was associated with lower A beta(1-42) and A beta(1-40) CSF levels and increased centrum semiovale EPVS burden, but did not independently influence clinical phenotype nor the rate of cognitive decline within our follow-up time window.