title: Risk of stroke from new carotid artery occlusion in the Asymptomatic Carotid Surgery Trial-1.
abstract: OBJECTIVE
  In the Asymptomatic Carotid Surgery Trial-1 (ACST-1), 3120 patients with tight asymptomatic carotid stenosis were randomly assigned to medical treatment alone or to carotid endarterectomy and appropriate medication. Successful carotid endarterectomy significantly reduced 10-year stroke risk in younger patients. This study was undertaken to determine the risk of new occlusion and stroke during trial follow-up.
  
  
  METHODS
  Patients with contralateral occlusion at trial entry (n=276) or incomplete duplex follow-up (n=137) were excluded. Risk of occlusion and stroke in patients with occlusion was estimated by Kaplan-Meier analysis. Cox proportional hazard regression models were used to determine risk factors for developing new occlusion and stroke.
  
  
  RESULTS
  Median follow-up in 2707 patients was 80.0 months (interquartile range, 52.0-115.0). New occlusions occurred in 197 patients (1.1% per annum) but were more likely to occur in arteries with tight stenosis and in unoperated patients. Overall risk of stroke was 7.6% (95% confidence interval [CI], 6.6-8.7) and 15.5% (95% CI, 13.6-17.4) at 5 and 10 years, respectively; for patients with new occlusion, this significantly increased to 17.0% (95% CI, 11.6-22.4) and 20.8% (95% CI, 14.1-26.2), respectively (P<0.001). Stroke was significantly more likely to occur in patients developing occlusion (hazard ratio, 1.78; 95% CI, 1.26-2.51) irrespective of allocated treatment.
  
  
  CONCLUSIONS
  New occlusions were uncommon after carotid endarterectomy in ACST-1. During long-term follow-up, occlusion and stroke were commoner among patients with ≥ 70% stenosis, most of whom had not undergone carotid endarterectomy. Occlusion was an independent prognostic risk factor for occurrence of stroke.
authors: Department of Vascular Surgery, UMC Utrecht, Utrecht, The Netherlands.
authors: Anne G
authors: AG
authors: den Hartog
authors: Alison W
authors: AW
authors: Halliday
authors: Elizabeth
authors: E
authors: Hayter
authors: Hongchao
authors: H
authors: Pan
authors: Xing
authors: X
authors: Kong
authors: Frans L
authors: FL
authors: Moll
authors: Gert Jan
authors: GJ
authors: de Borst
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D016893:Carotid Stenosis / Q000150:complications* / Q000628:therapy*; D003131:Combined Modality Therapy; D016894:Endarterectomy, Carotid; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012008:Recurrence; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*; D013997:Time Factors
chemical_list: D000959:Antihypertensive Agents; D005343:Fibrinolytic Agents
keywords: carotid occlusive disease; carotid stenosis; stroke