Localized network damage related to white matter hyperintensities is linked to worse outcome after severe stroke.

Abstract

White matter hyperintensities of presumed vascular origin (WMH) are associated with various clinical sequelae. In stroke patients, the total WMH burden is linked to recurrent cerebrovascular events and worse clinical outcomes. As WMH also affect the integrity of large-scale structural brain networks, we hypothesize that the extent of WMH-related network damage carries relevant information to explain outcome variability in addition to global WMH volume. Clinical and structural brain imaging data of 33 severely affected acute stroke patients were analyzed from two independent cohorts. Imaging data were acquired within the first two weeks after stroke. WMH-related localized and global network damage was derived. WMH network effects were differentially assessed for total, periventricular (pWMH), and deep WMH (dWMH). Using ordinal logistic regression analyses, network damage was associated with functional outcome at follow-up after three to six months. WMH were linked to a significant disconnection of multiple cortical and subcortical brain regions. Global and localized pWMH-related network damage affecting distinct brain regions of both hemispheres were independently associated with a worse outcome after adjustment for baseline symptom burden, age, brain infarct volume, and total WMH volume. Total and dWMH-related network disturbances did not show similar associations. This study indicates that pWMH-related network damage affecting specific brain regions is linked to functional outcome in acute stroke patients. It underscores the potential significance of pre-existing WMH-related network damage as a crucial factor in comprehending outcome variability after severe stroke.