White matter hyperintensity volume is increased in small vessel stroke subtypes

Objective: White matter hyperintensity (WMH) may be a marker of an underlying cerebral microangiopathy. Therefore, we hypothesized that WMH would be most severe in patients with lacunar stroke and intracerebral hemorrhage (ICH), 2 types of stroke in which cerebral small vessel (SV) changes are pathophysiologically relevant.

Methods: We determined WMH volume (WMHV) in cohorts of prospectively ascertained patients with acute ischemic stroke (AIS) (Massachusetts General Hospital [MGH], n = 628, and the Ischemic Stroke Genetics Study [ISGS], n = 263) and ICH (MGH, n = 122).

Results: Median WMHV was 7.5 cm³ (interquartile range 3.4–14.7 cm³) in the MGH AIS cohort (mean age 65 ± 15 years). MGH patients with larger WMHV were more likely to have lacunar stroke compared with cardioembolic (odds ratio [OR] = 1.87 per SD normally transformed WMHV), large artery (OR = 2.25), undetermined (OR = 1.87), or other (OR = 1.85) stroke subtypes (p < 0.03). These associations were replicated in the ISGS cohort (p = 0.03). In a separate analysis, greater WMHV was seen in ICH compared with lacunar stroke (OR = 1.2, p < 0.02) and in ICH compared with all ischemic stroke subtypes combined (OR = 1.34, p < 0.007).

Conclusions: Greater WMH burden was associated with SV stroke compared with other ischemic stroke subtypes and, even more strongly, with ICH. These data, from 2 independent samples, support the model that increasing WMHV is a marker of more severe cerebral SV disease and provide further evidence for links between the biology of WMH and SV stroke.