title: Prospective controlled study of the natural history of asymptomatic 60% to 69% carotid stenosis according to ultrasonic plaque morphology.
abstract: OBJECTIVE
  In spite of the conclusions of the Asymptomatic Carotid Atherosclerosis Study, some clinicians are still reluctant to recommend carotid endarterectomy (CEA) for patients with asymptomatic > or = 60% carotid stenosis (ACS). This study analyzes the natural history of 60% to 69% ACS according to ultrasonic plaque morphology and its implication on treatment.
  
  
  METHODS
  During a 2-year period, patients with 60% to 69% ACS entered into a protocol of carotid duplex scan surveillance/clinical examination every 6 months. The ultrasonic plaque morphology was classified as heterogeneous (group A, n = 162) or homogeneous (group B, n = 229) with HDI 3000/HDI 5000 systems (Advanced Technology Laboratories, Bothwell, Wash). CEA was done if lesion progressed to > or = 70% stenosis or became symptomatic.
  
  
  RESULTS
  Three hundred eighty-two patients (391 arteries) were followed for a mean interval of 37 months. The clinical/demographic characteristics were similar for both groups. The incidence rate of future ipsilateral strokes was significantly higher in group A than in group B: 13.6% versus 3.1% (P =.0001; odds ratio [OR], 5). Similarly, the incidence rate of all neurologic events (stroke or transient ischemic attack [TIA]) was higher in group A than in group B: 27.8% versus 6.6% (P =.0001; OR, 5.5). Progression to > or = 70% stenosis was also higher in group A than in group B: 25.3% versus 6.1% (P =.0001; OR, 5.2). Forty-four late CEAs (27.2%) were done in group A (16 for stroke, 21 for TIA, and seven for > or = 70% ACS) versus 13 (5.7%) in group B (five for stroke, seven for TIA, and one for > or = 70% ACS; P =.0001; OR, 6.2).
  
  
  CONCLUSIONS
  Patients with 60% to 69% ACS with heterogeneous plaque had a higher incidence rate of late stroke, TIA, and progression to > or = 70% stenosis than patients with homogeneous plaque. Prophylactic CEA for 60% to 69% ACS may be justified if associated with heterogeneous plaque.
authors.affiliation: Department of Vascular Surgery, Robert C. Byrd Health Sciences Center, West Virginia University, Charleston, USA.
authors.forename: Ali F
authors.initials: AF
authors.lastname: Aburahma
authors.forename: Stefan P
authors.initials: SP
authors.lastname: Thiele
authors.forename: John T
authors.initials: JT
authors.lastname: Wulu
mesh_terms: D000368:Aged; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D018450:Disease Progression; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D018616:Ultrasonography, Doppler, Duplex