title: Ultrasonic tissue characterization of carotid plaque improves the prediction of cardiovascular events in diabetic patients: a pilot study.
abstract: OBJECTIVE
  The aim of this study is to evaluate whether noninvasive ultrasonic tissue characterization of carotid plaque using integrated backscatter (IBS) analysis can be a predictor of future cardiovascular events (CVE) in asymptomatic type 2 diabetic patients.
  
  
  METHODS
  We prospectively evaluated the association between Calibrated-IBS value, an ultrasonic marker for tissue characteristics of carotid plaque, and CVE in 85 asymptomatic type 2 diabetic patients with carotid plaque.
  
  
  RESULTS
  The median follow-up period was 7.9 years, and there were 20 new CVE. The risk of CVE was significantly higher in the subjects with low Calibrated-IBS values (<-17.1 dB; n = 42) as compared with those with high values (≥-17.1 dB; n = 43) (P = 0.004, log-rank test). Cox proportional hazards regression analysis revealed that both Calibrated-IBS value (hazard ratio [HR] 0.802 [95% CI 0.710-0.906]; P < 0.0001) and plaque thickness (1.938 [1.170-3.213]; P = 0.010) were independently associated with CVE, even after adjustment for the 10-year risk for a general cardiovascular disease estimated by Framingham risk scoring (FRS). Time-dependent receiver operating characteristic curve analysis for CVE at 10 years after the baseline examinations revealed that area under the curve for Calibrated-IBS was 0.76 (0.60-0.90) and substantially higher than those for plaque thickness (0.60 [0.45-0.79]) and FRS (0.60 [0.40-0.78]). These analyses also revealed that the addition of both plaque thickness and Calibrated-IBS value to conventional risk factors significantly improved the event prediction.
  
  
  CONCLUSIONS
  Calibrated-IBS value could improve the risk prediction of CVE in asymptomatic type 2 diabetic patients with carotid plaque.
authors.affiliation: Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Suita, Japan. katakami@medone.med.osaka-u.ac.jp
authors.forename: Naoto
authors.initials: N
authors.lastname: Katakami
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Takahara
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kaneto
authors.forename: Ken'ya
authors.initials: K
authors.lastname: Sakamoto
authors.forename: Kazutomi
authors.initials: K
authors.lastname: Yoshiuchi
authors.forename: Yoko
authors.initials: Y
authors.lastname: Irie
authors.forename: Fumiyo
authors.initials: F
authors.lastname: Kubo
authors.forename: Takashi
authors.initials: T
authors.lastname: Katsura
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Yamasaki
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kosugi
authors.forename: Iichiro
authors.initials: I
authors.lastname: Shimomura
mesh_terms: D000368:Aged; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000209:etiology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D012307:Risk Factors; D014463:Ultrasonography