Dementia incidence and predictors in cerebral amyloid angiopathy patients without intracerebral hemorrhage

Abstract

Cerebral amyloid angiopathy (CAA) is a common cause of cognitive impairment in older individuals. This study aimed to investigate predictors of dementia in CAA patients without intracerebral hemorrhage (ICH). A total of 158 non-demented patients from the Stroke Service or the Memory Clinic who met the modified Boston Criteria for probable CAA were included. At baseline, neuroimaging markers, including lobar microbleeds (cerebral microbleeds (CMBs)), white matter hyperintensities (WMH), cortical superficial siderosis (cSS), magnetic resonance imaging (MRI)-visible centrum semiovale perivascular spaces (CSO-PVS), lacunes, and medial temporal atrophy (MTA) were assessed. The overall burden of small vessel disease (SVD) for CAA was calculated by a cumulative score based on CMB number, WMH severity, cSS presence and extent and CSO-PVS severity. The estimated cumulative dementia incidence at 1 year was 14% (95% confidence interval (CI): 5%-23%), and 5 years 73% (95% CI: 55%, 84%). Age (hazard ratio (HR) 1.05 per year, 95% CI: 1.01-1.08, p = 0.007), presence of MCI status (HR 3.40, 95% CI: 1.97-6.92, p < 0.001), MTA (HR 1.71 per point, 95% CI: 1.26-2.32, p = 0.001), and SVD score (HR 1.23 per point, 95% CI: 1.20-1.48, p = 0.030) at baseline were independent predictors for dementia conversion in these patients. Cognitive deterioration of CAA patients appears attributable to cumulative changes, from both vasculopathic and neurodegenerative lesions.

Keywords: Amyloid angiopathy; cerebrovascular disease; dementia; magnetic resonance imaging.

Figure 1.

“Other” refers to patients excluded for being scanned for unrelated events or as part of a systematic and non-related protocol for different diseases. “Mixed” refers to the mixture of lobar and deep. ICH: intracerebral hemorrhage; CMBs: cerebral microbleeds; CAA: cerebral amyloid angiopathy; Infl.: inflammation; MR: magnetic resonance.

Figure 2.

Multiple bilateral lobar microbleeds (CMBs) detected on T2*-GRE. These microbleeds are round or ovoid shaped hypointense signal on T2*-GRE/SWI and generally 2–5 mm in diameter (a). Centrum semiovale perivascular spaces (CSO-PVS) with signal intensity similar to CSF detected on T2. These fluid-filled spaces follow the typical course of a vessel and appear linear, round, or ovoid (b). Focal cortical superficial siderosis (cSS) detected as curvillinear signal in the superficial layer of the cerebral cortex on T2*-GRE (c). One lacune detected on T2-FLAIR (d). Lacunes are generally round or void (3–15 mm in diameter), subcortical and fluid-filled cavity with signal intensity similar to CSF.

Figure 3.

Comparison with adjustment of age and MCI status at baseline (p = 0.674).