title: Severity of asymptomatic carotid stenosis and risk of ipsilateral hemispheric ischaemic events: results from the ACSRS study.
abstract: OBJECTIVE
  This study determines the risk of ipsilateral ischaemic neurological events in relation to the degree of asymptomatic carotid stenosis and other risk factors.
  
  
  METHODS
  Patients (n=1115) with asymptomatic internal carotid artery (ICA) stenosis greater than 50% in relation to the bulb diameter were followed up for a period of 6-84 (mean 37.1) months. Stenosis was graded using duplex, and clinical and biochemical risk factors were recorded.
  
  
  RESULTS
  The relationship between ICA stenosis and event rate is linear when stenosis is expressed by the ECST method, but S-shaped if expressed by the NASCET method. In addition to the ECST grade of stenosis (RR 1.6; 95% CI 1.21-2.15), history of contralateral TIAs (RR 3.0; 95% CI 1.90-4.73) and creatinine in excess of 85 micromol/L (RR 2.1; 95% CI 1.23-3.65) were independent risk predictors. The combination of these three risk factors can identify a high-risk group (7.3% annual event rate and 4.3% annual stroke rate) and a low risk group (2.3% annual event rate and 0.7% annual stroke rate).
  
  
  CONCLUSIONS
  Linearity between ECST per cent stenosis and risk makes this method for grading stenosis more amenable to risk prediction without any transformation not only in clinical practice but also when multivariable analysis is to be used. Identification of additional risk factors provides a new approach to risk stratification and should help refine the indications for carotid endarterectomy.
authors.affiliation: Department of Vascular Surgery, Imperial College, London, UK. anicolai@cing.ac.cy
authors.forename: A N
authors.initials: AN
authors.lastname: Nicolaides
authors.forename: S K
authors.initials: SK
authors.lastname: Kakkos
authors.forename: M
authors.initials: M
authors.lastname: Griffin
authors.forename: M
authors.initials: M
authors.lastname: Sabetai
authors.forename: S
authors.initials: S
authors.lastname: Dhanjil
authors.forename: T
authors.initials: T
authors.lastname: Tegos
authors.forename: D J
authors.initials: DJ
authors.lastname: Thomas
authors.forename: A
authors.initials: A
authors.lastname: Giannoukas
authors.forename: G
authors.initials: G
authors.lastname: Geroulakos
authors.forename: N
authors.initials: N
authors.lastname: Georgiou
authors.forename: S
authors.initials: S
authors.lastname: Francis
authors.forename: E
authors.initials: E
authors.lastname: Ioannidou
authors.forename: C J
authors.initials: CJ
authors.lastname: Doré
mesh_terms: D002545:Brain Ischemia / Q000453:epidemiology* / Q000209:etiology; D016893:Carotid Stenosis / Q000150:complications / Q000000981:diagnostic imaging*; D006801:Humans; D015994:Incidence; D011237:Predictive Value of Tests; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology; D018616:Ultrasonography, Doppler, Duplex