title: The Value of Elastic Modulus Index as a Novel Surrogate Marker for Cardiovascular Risk Stratification by Dimensional Speckle-Tracking Carotid Ultrasonography.
abstract: BACKGROUND
  Carotid intima media thickness (CIMT) and the presence of carotid plaque have been used for risk stratification of cardiovascular disease (CVD). To date, however, the association between multi-directional functional properties of carotid artery and CVD has not been fully elucidated. We sought to explore the multi-directional mechanics of the carotid artery in relation to cardiovascular risk.
  
  
  METHODS
  Four hundred one patients who underwent carotid ultrasound were enrolled between January 2010 and April 2013. A high risk of CVD was defined as more than 20% of 10-year risk based on the Framingham risk score. Using a speckle-tracking technique, the longitudinal and radial movements were analyzed in the B-mode images. Peak longitudinal and radial displacements, strain and strain rate were also measured. Beta stiffness and elastic modulus index were calculated from the radial measurements.
  
  
  RESULTS
  Of the overall sample, 13% (52) of patients comprised the high-risk group. In multivariate logistic regression, CIMT and elastic modulus index were independently associated with a high-risk of CVD {odds ratio (OR): 1.810 [95% confidence interval (CI) 1.249-2.622] and OR: 1.767 (95% CI: 1.177-2.652);p= 0.002, 0.006, respectively}. The combination of CIMT and elastic modulus index correlated with a high-risk of CVD more so than CIMT alone.
  
  
  CONCLUSIONS
  The elastic modulus index of the carotid artery might serve as a novel surrogate marker of high-risk CVD. Measurement of the multi-directional mechanics of the carotid artery using the speckle tracking technique has potential for providing further information over conventional B-mode ultrasound for stratification of CVD risk.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.; Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.; Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: In-Jeong
authors.initials: IJ
authors.lastname: Cho
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.; Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea.; Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyuk-Jae
authors.initials: HJ
authors.lastname: Chang
authors.affiliation: Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ji Min
authors.initials: JM
authors.lastname: Sung
authors.affiliation: Infrastructure Technology Lab, Samsung Medison, Seoul, Korea.
authors.forename: Jinyong
authors.initials: J
authors.lastname: Lee
authors.affiliation: Infrastructure Technology Lab, Samsung Medison, Seoul, Korea.
authors.forename: Hojin
authors.initials: H
authors.lastname: Ryoo
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.; Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Chi Young
authors.initials: CY
authors.lastname: Shim
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.; Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Geu-Ru
authors.initials: GR
authors.lastname: Hong
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.; Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Namsik
authors.initials: N
authors.lastname: Chung
keywords: Cardiovascular disease; Carotid artery; Elastic modulus