Small vessel versus large vessel vascular dementia: risk factors and MRI findings

The aim of this study was a cross-sectional comparison of clinical and MRI characteristics and risk factor profiles between patients with small vessel disease (lacunae and white matter hyperintensities) and large vessel disease (large territorial or strategical infarcts) in a large cohort of VaD patients.

Patients with VaD (NINDS-AIREN) were included in a large multicenter treatment trial (the VantagE study). All patients were examined by a neurologist and interviewed about their medical history. Based on MRI, patients were classified as having large vessel VaD, small vessel VaD, or a combination. Other MRI characteristics included white matter hyperintensities (WMH), medial temporal lobe atrophy (MTA) and general cortical atrophy.

Of the 706 patients, 522 (74 %) had small vessel disease, 126 (18 %) had large vessel disease and 58 (8 %) had both. Patients with small vessel disease were older and less educated, and showed more cortical and medial temporal lobe atrophy than patients with large vessel disease. The most prevalent vascular risk factors (hypertension, diabetes and smoking) were equally distributed between the different types of VaD. However, patients with large vessel disease had more hypercholesterolemia and cardiac risk factors compared to patients with small vessel disease.

Cerebrovascular disease underlying VaD consists in the majority of small vessel disease and in about one fifth of large vessel disease. This study demonstrates heterogeneity between these two groups with regard to risk factor profile and atrophy scores on MRI.