Stroke mechanisms and outcomes of isolated symptomatic basilar artery stenosis

Edgar A. Samaniego, Amir Shaban, Santiago Ortega-Gutierrez, Jorge A. Roa, David M. Hasan, Colin Derdeyn, Biyue Dai, Harold Adams, Enrique Leira

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Background While diffuse atherosclerotic disease affecting the posterior circulation has been described extensively, the prevalence, natural history and angiographic characteristics of isolated symptomatic basilar artery stenosis (ISBAS) remain unknown. Methods We reviewed our prospective institutional database to identify patients with ≥50% symptomatic basilar artery (BA) stenosis without significant atherosclerotic burden in the vertebral or posterior cerebral arteries. Stroke mechanism, collateral circulation, and degree and length of stenosis were analysed. The primary outcome was time from index event to new transient ischaemic attack (TIA), acute ischaemic stroke (AIS) or death. Other outcome variables included modified Rankin Scale (MRS) score on discharge and last follow-up. Results Of 6369 patients with AIS/TIA, 91 (1.43%) had ISBAS. Seventy-three (80.2%) patients presented with AIS and 18 (19.8%) with TIA. Twenty-nine (31.9%) were women and the median age was 66.8±13.6 years. The mean follow-up time was 2.7 years. The most common stroke mechanism was artery-to-artery thromboembolism (45.2%), followed by perforator occlusion (28.7%) and flow-dependent/hypoperfusion (15.1%). The percentage of stenosis was lower in patients who had favourable outcome compared with those with MRS 3-6 on discharge (78.3±14.3 vs 86.9±14.5, p=0.007). Kaplan-Meier curves showed higher recurrence/death rates in patients with ≥80% stenosis, mid-basilar location and poor collateral circulation. Approximately 13% of patients with ISBAS presented with complete BA occlusion. Conclusion ISBAS is an uncommon (1.43%) cause of TIA and AIS. Men in their 60s are mostly affected, and artery-to-artery embolism is the most common stroke mechanism. Mid-basilar location, ≥80% stenosis and poor collateral circulation are important factors associated with worse prognosis.

Original languageEnglish (US)
Pages (from-to)189-197
Number of pages9
JournalStroke and Vascular Neurology
Issue number4
StatePublished - Dec 1 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© Author(s) (or their employer(s)) 2019.


  • basilar artery stenosis
  • collateral circulation
  • intracranial atherosclerotic disease
  • ischaemic stroke
  • posterior circulation
  • stroke mechanism
  • transient ischemic attack


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