Summary
There has been little information regarding the impact of unrecognised brain infarctions
(UBIs) on stroke outcome in patients with nonvalvular atrial fibrillation (NVAF).
By using volumetric analysis of ischaemic lesions, we evaluated the potential impact
of UBIs on clinical outcome according to their presence and categorised type. This
study enrolled 631 patients with NVAF having no clinical stroke history. UBIs were
categorised into three types as territorial, lacunar, or subcortical. We collected
stroke severity, functional outcome at three months, and the total volume of UBIs
and acute infarction lesions. We investigated the association between clinical outcome
and the type or volume of UBI, using a linear mixed model and logistic regression
analysis. UBIs were detected in 285 (45.2 %) patients; territorial UBIs were observed
in 24.4 % of patients (154/631), lacunar UBIs in 25 % (158/631), and subcortical UBIs
in 15.7 % (99/631). Although initial stroke severity was not different between patients
with UBIs and those without, those with UBIs had less improvement during hospitalisation,
leading to poorer outcome at three months. Among the three types of UBIs, only territorial
UBIs were associated with poor outcome, especially in patients with relatively smaller
acute infarction volume. UBIs, in particular, territorial UBIs, may be considered
as predictors for poor outcome after ischaemic stroke in patients with NVAF. Our results
suggest that the impact of UBIs on clinical outcome differs according to the type
of UBIs and the acute stroke severity.
Keywords
Unrecognised brain infarction - non-valvular atrial fibrillation - outcome