title: Ultrasound and Clinical Predictors of Recurrent Ischemia in Symptomatic Internal Carotid Artery Occlusion.
abstract: OBJECTIVE
  Occlusion of the internal carotid artery puts patients at risk of recurrent ischemic events because of hemodynamic compromise. Our goal was to characterize clinical and duplex parameters indicating patients at risk of recurrent ischemia.
  
  
  METHODS
  We retrospectively identified patients with symptomatic internal carotid artery occlusion. Clinical characteristics and ultrasound parameters, including collateral networks, were analyzed. Predictors for recurrent ipsilateral ischemia were investigated by Cox regression analysis.
  
  
  RESULTS
  Of 68 patients, at least 1 recurrent ischemic event within the same vascular territory was observed in 14 patients (20.6%) within 2 to 92 days (median, 29.5 days). The median follow-up period was 6 months. Diabetes mellitus and previous transient ischemic attack were associated with recurrence, as was activation of the maximum number of collateral pathways on transcranial ultrasound (28.6% versus 5.6%; P=0.03). Furthermore, flow in the posterior cerebral arteries was higher in patients with recurrence in ipsilateral and contralateral posterior cerebral artery P2 segments (76 IQR 37.5 versus 59, IQR 22.5 cm/s and 68, IQR 35.6 versus 52, IQR 21 cm/s; P<0.01 and 0.02).
  
  
  CONCLUSIONS
  Flow increases in both posterior cerebral artery P2 segments suggest intensified compensatory efforts when other collaterals are insufficient. Together with the presence of diabetes mellitus and a history of transient ischemic attack, this duplex parameter indicates that patients with internal carotid artery are at particular risk of recurrent ischemia.
authors.affiliation: From the Division of Vascular Neurology and Rehabilitation, Department of Neurology, University Hospital Zurich and University of Zurich (J.S., A.R.L., S.W.) and Department of Biostatistics, Institute of Epidemiology, Biostatistics and Prevention (B.S.), University of Zurich, Switzerland; and Cereneo Center for Neurology and Rehabilitation, Vitznau, Switzerland (A.R.L.).
authors.forename: Juliane
authors.initials: J
authors.lastname: Schneider
authors.affiliation: From the Division of Vascular Neurology and Rehabilitation, Department of Neurology, University Hospital Zurich and University of Zurich (J.S., A.R.L., S.W.) and Department of Biostatistics, Institute of Epidemiology, Biostatistics and Prevention (B.S.), University of Zurich, Switzerland; and Cereneo Center for Neurology and Rehabilitation, Vitznau, Switzerland (A.R.L.).
authors.forename: Beate
authors.initials: B
authors.lastname: Sick
authors.affiliation: From the Division of Vascular Neurology and Rehabilitation, Department of Neurology, University Hospital Zurich and University of Zurich (J.S., A.R.L., S.W.) and Department of Biostatistics, Institute of Epidemiology, Biostatistics and Prevention (B.S.), University of Zurich, Switzerland; and Cereneo Center for Neurology and Rehabilitation, Vitznau, Switzerland (A.R.L.).
authors.forename: Andreas R
authors.initials: AR
authors.lastname: Luft
authors.affiliation: From the Division of Vascular Neurology and Rehabilitation, Department of Neurology, University Hospital Zurich and University of Zurich (J.S., A.R.L., S.W.) and Department of Biostatistics, Institute of Epidemiology, Biostatistics and Prevention (B.S.), University of Zurich, Switzerland; and Cereneo Center for Neurology and Rehabilitation, Vitznau, Switzerland (A.R.L.). Susanne.Wegener@usz.ch.
authors.forename: Susanne
authors.initials: S
authors.lastname: Wegener
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002340:Carotid Artery Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D002536:Cerebral Arteries / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation; D015331:Cohort Studies; D003097:Collateral Circulation; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D002546:Ischemic Attack, Transient / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D016016:Proportional Hazards Models; D012008:Recurrence; D015356:Retinal Artery Occlusion / Q000453:epidemiology* / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D010975:Platelet Aggregation Inhibitors
keywords: diabetes mellitus; posterior cerebral artery; stroke; ultrasonography, Doppler, transcranial