Glymphatic dysfunction correlates with severity of small vessel disease and cognitive impairment in cerebral amyloid angiopathy

Background and purpose Cerebral amyloid angiopathy (CAA) is characterized by beta-amyloid deposition in cortical and leptomeningeal arterioles, which might result from glymphatic dysfunction. The aim was to explore glymphatic function in CAA using the non-invasive diffusion tensor image analysis along the perivascular space method. Methods Sixty-three patients with CAA were prospectively recruited together with seventy age- and sex-matched normal controls. The Mini-Mental State Examination and Montreal Cognitive Assessment were applied to screen global cognitive status. Magnetic resonance imaging scans were conducted to calculate the index for diffusivity along the perivascular space (ALPS index), and linear regression models were used to assess its relationships with cerebral small vessel disease (CSVD) markers, cognitive status and blood biomarkers. Cox proportional hazard models were applied to explore the role of the baseline ALPS index in disease recurrence. Results Patients with CAA exhibited a lower ALPS index than controls globally (p < 0.001). In addition, a lower ALPS index was related to more enlarged perivascular space in basal ganglia (p = 0.026), more lacunes (p < 0.001), higher white matter hyperintensity Fazekas score (p = 0.049), elevated total magnetic resonance imaging burden of CSVD (p = 0.034) and lower Mini-Mental State Examination (p = 0.001) as well as Montreal Cognitive Assessment (p < 0.001) in CAA. During a median follow-up of 4.1 years, a higher ALPS index was associated with lower disease recurrence (p = 0.022). The ALPS index was also negatively correlated with serum soluble intercellular adhesion molecule-1, neurofilament light and chitinase-3-like protein 1 in CAA. Conclusions Patients with CAA showed impaired glymphatic function. The ALPS index was significantly related to CSVD severity, cognitive impairment and disease recurrence in CAA.