Cerebral amyloid angiopathy in a multicenter cohort of people with MCI and Alzheimer's disease

Abstract

The well-known MRI correlates of cerebral amyloïd angiopathy (CAA) include brain microbleeds (BMB) and white matter changes. Cortical superficial siderosis has been recently recognized as CAA imaging correlates. The prevalence of this hemorrhagic lesion is unknown in Alzheimer disease (AD) patients. The objective was to describe the prevalence of the MRI correlates of CAA in a multicenter cohort of mild cognitive impairment (MCI) and AD patients. Consecutive amnestic MCI (a-MCI), non-amnestic MCI (na-MCI), and AD patients from 4 French memory centers (Paris, Strasbourg, Lille, Montpellier) were included. A 3 Tesla MRI with a standardized protocol was performed. White matter changes in the periventricular (PVH) and sub-cortical (WMH) regions were assessed using the Fazekas scale, BMB were assessed using the BOMBS scale, and cortical superficial siderosis (SH-CSS) was recorded, in the absence of validated scale. 289 patients (mean age: 77.3±6.5 years) were included: 126 (43.6%) AD patients (mean MMSE: 22.1±3.6), 126 (43.6%) a-MCI patients (mean MMSE 26.4±2.5) and 37 (12.7%) na-MCI patients (mean MMSE 27.6±1.9), without significant differences between the 3 sub-groups on age and gender. There was no significant difference between the 3 sub-groups of patients on vascular risk factors. Only 3 patients had no PVH and/or WMH, 111 (38.4%) patients had at least one BMB, 9 (3.1%) patients had at least one SH-CSS, without significant difference between the 3 sub-groups of patients. SH-CSS was significantly associated with PVH (p=0.0062) and WMH (p=0.0001), unlike BMB (p=0.75). 112 (34%) patients had probable or possible CAA according to the modified Boston criteria with an equal repartition in the 3 sub-groups. CAA was highly prevalent in this AD and MCI multicenter cohort. CAA is a non-inclusion condition for amyloïd disease-modifier trials. More than a third of patients of our cohort would not have access to these treatments.