title: Risk of Stroke at the Time of Carotid Occlusion.
abstract: OBJECTIVE
  Many patients with asymptomatic carotid stenosis are offered carotid stenting for the prevention of carotid occlusion. However, this treatment may be inappropriate if the risk of stroke is low at the time of occlusion and with intensive medical therapy.
  
  
  OBJECTIVE
  To determine the risk resulting from progression to occlusion among patients with asymptomatic carotid stenosis and to assess the role of severity of carotid stenosis or the presence of contralateral occlusion as factors that may predict the risk of stroke or death after occlusion of a previously asymptomatic carotid stenosis.
  
  
  METHODS
  We conducted a retrospective analysis of data collected from patients at the Stroke Prevention Clinic of Victoria Hospital from January 1, 1990 (when annual surveillance with carotid ultrasonography first began), through December 31, 1995, or the Stroke Prevention at University Hospital from January 1, 1995, through December 31, 2012. The last date of follow-up was August 26, 2014.
  
  
  METHODS
  A new carotid occlusion during annual monitoring with carotid duplex ultrasonography (index occlusion).
  
  
  METHODS
  Ipsilateral stroke or transient ischemic attack, death from ipsilateral stroke, or death from unknown cause.
  
  
  RESULTS
  Among 3681 patients in our clinic database with data on sequential annual carotid ultrasonographic examinations during the study period, 316 (8.6%) were asymptomatic before an index occlusion that occurred during observation. Most of the new occlusions (254 of 316 [80.4%]) occurred before 2002, when medical therapy was less intensive; the frequency decreased by quartile of years (P < .001, χ2 test). Only 1 patient (0.3%) had a stroke at the time of the occlusion, and only 3 patients (0.9%) had an ipsilateral stroke during follow-up (all before 2005). In Kaplan-Meier survival analyses, neither severity of stenosis (P = .80, log-rank test) nor contralateral occlusion (P = .73) predicted the risk of ipsilateral stroke or transient ischemic attack, death from stroke, or death from unknown cause at a mean (SD) follow-up of 2.56 (3.64) years. In Cox proportional hazards regression analyses, only age (P = .02), sex (P = .01), and carotid plaque burden (P = .006) significantly predicted risk of those events.
  
  
  CONCLUSIONS
  The risk of progression to carotid occlusion is well below the risk of carotid stenting or endarterectomy and has decreased markedly with more intensive medical therapy. Preventing carotid occlusion may not be a valid indication for stenting.
authors.affiliation: Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Yang
authors.affiliation: Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, Western University, London, Ontario, Canada.
authors.forename: Chrysi
authors.initials: C
authors.lastname: Bogiatzi
authors.affiliation: Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, Western University, London, Ontario, Canada.
authors.forename: J David
authors.initials: JD
authors.lastname: Spence
mesh_terms: D000368:Aged; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000517:prevention & control; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D002423:Cause of Death; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002546:Ischemic Attack, Transient / Q000453:epidemiology* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012720:Severity of Illness Index; D020521:Stroke / Q000453:epidemiology* / Q000401:mortality; D014463:Ultrasonography