title: Carotid plaque area: a tool for targeting and evaluating vascular preventive therapy.
abstract: OBJECTIVE
  Carotid plaque area measured by ultrasound (cross-sectional area of longitudinal views of all plaques seen) was studied as a way of identifying patients at increased risk of stroke, myocardial infarction, and vascular death.
  
  
  METHODS
  Patients from an atherosclerosis prevention clinic were followed up annually for up to 5 years (mean, 2.5+/-1.3 years) with baseline and follow-up measurements recorded. Plaque area progression (or regression) was defined as an increase (or decrease) of >/=0.05 cm(2) from baseline.
  
  
  RESULTS
  Carotid plaque areas from 1686 patients were categorized into 4 quartile ranges: 0.00 to 0.11 cm(2) (n=422), 0.12 to 0.45 cm(2) (n=424), 0.46 to 1.18 cm(2) (n=421), and 1.19 to 6.73 cm(2) (n=419). The combined 5-year risk of stroke, myocardial infarction, and vascular death increased by quartile of plaque area: 5.6%, 10.7%, 13.9%, and 19.5%, respectively (P<0.001) after adjustment for all baseline patient characteristics. A total of 1085 patients had >/=1 annual carotid plaque area measurements: 685 (63.1%) had carotid plaque progression, 306 (28.2%) had plaque regression, and 176 (16.2%) had no change in carotid plaque area over the period of follow-up. The 5-year adjusted risk of combined outcome was 9.4%, 7.6%, and 15.7% for patients with carotid plaque area regression, no change, and progression, respectively (P=0.003).
  
  
  CONCLUSIONS
  Carotid plaque area and progression of plaque identified high-risk patients. Plaque measurement may be useful for targeting preventive therapy and evaluating new treatments and response to therapy and may improve cost-effectiveness of secondary preventive treatment.
authors.affiliation: Robarts Research Institute and University of Western Ontario, London. dspence@robarts.ca
authors.forename: J David
authors.initials: JD
authors.lastname: Spence
authors.forename: Michael
authors.initials: M
authors.lastname: Eliasziw
authors.forename: Maria
authors.initials: M
authors.lastname: DiCicco
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Hackam
authors.forename: Ramzy
authors.initials: R
authors.lastname: Galil
authors.forename: Tara
authors.initials: T
authors.lastname: Lohmann
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D002340:Carotid Artery Diseases / Q000145:classification* / Q000000981:diagnostic imaging*; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000517:prevention & control; D011237:Predictive Value of Tests; D012075:Remission, Spontaneous; D012306:Risk; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000517:prevention & control*; D014463:Ultrasonography