Background: The risk of recurrent stroke in patients with ischemic stroke with vertebral/basilar artery stenosis remains to be systematically studied.
Methods: We analyzed data from Taiwan Stroke Registry (TSR), with stroke registries provided by 59 hospitals. Patients who had diagnosis of ischemic stroke and were categorized into the “large artery atherosclerosis” group by TOAST who underwent CTA, MRA, or catheter- based angiography were identified for the present study. The patients were divided into 3 groups based on the extent of vertebral (VA) and/or basilar artery (BA) stenosis as follows: 0-49%, 50-99%, and 100% (total occlusion). Cox proportional hazards model was used to determine the hazard ratios (HRs) of recurrent stroke within 1 year of index event after adjusting for all relevant risk factors by univariable Cox model.
Results: In the TSR data base, 84,831patients were in the ischemic stroke group. Based on TOAST, 20,220 patients were in the large-artery atherosclerosis group. Among these patients, a total of 10,515 were of age 18 or greater who had CTA, MRA or angiographic studies that included VA/BA. There were 6,972 subjects with VA/BA stenosis in the 0-49%, 3,137 in the 50-99% and 406 in the 100% (total occlusion) groups respectively. With VA/BA stenosis in the 0-49% range as the reference, HRs of recurrent stroke in one year by multivariable modeling with adjustment of all relevant risk factors by univariable Cox model was 1. 29 (95% CI, 1.05 - 1.58, p<0.05) in the 50-99% and 1.64 (95% CI, 1.07 - 2.52, p<0.05) in the 100 % group with P trend < 0.02, denoting that a greater extent of VA/BA stenosis was associated with a relatively greater risk of recurrent stroke in 1 year after stroke.
Conclusions: Vertebral or basilar artery stenosis or occlusion was relatively prevalent among patients with ischemic stroke categorized in the large artery artherosclerosis group by TOAST with greater extent of VA/BA stenosis carrying greater risk of recurrent stroke within 1 year after stroke.