Concurrent intracranial and extracranial artery stenosis and the prognosis of transient ischaemic symptoms or imaging-negative ischaemic stroke

Background and purpose Transient ischaemic attack (TIA), transient symptoms with infarction (TSI) and diffusion-weighted imaging (DWI)-negative acute ischaemic stroke (AIS) share similar aetiologies but are considered to have a rather benign prognosis. We intended to investigate the association between intracranial atherosclerotic stenosis (ICAS), extracranial atherosclerotic stenosis (ECAS) and the prognosis of patients with TIA, TSI and DWI-negative AIS. Methods Clinical and imaging data of eligible participants were derived from the Chinese Intracranial Atherosclerosis study, according to symptom duration, acute infarction on DWI and discharge diagnosis. Based on the severity and location of arterial atherosclerosis, we categorised the study population into four groups: no or <50% ICAS and no ECAS; >= 50% ICAS but no ECAS; no or <50% ICAS with ECAS; and concurrent >= 50% ICAS and ECAS. Using multivariable Cox regression models, we analysed the relationship between the severity and distribution of large artery atherosclerosis and the prognosis of TIA, TSI and DWI-negative AIS. Results A total of 806 patients were included, 67.3% of whom were male. The median age of the study participants was 63 years. Patients in the concurrent >= 50% ICAS and ECAS subgroup had both a significantly higher 1-year recurrence rate (adjusted HR 3.4 (95% CI 1.15 to 10.04), p=0.027) and a higher risk of composite vascular events (adjusted HR 3.82 (95% CI 1.50 to 9.72), p=0.005). Conclusions Concurrent ICAS and ECAS is associated with a higher possibility of 1-year recurrent stroke or composite vascular events. Large artery evaluation is necessary to assess patients with transient ischaemic symptoms or DWI-negative AIS. Progress in shortening the time interval between symptom onset and large vessel evaluation is needed.