title: Association between wall shear stress and carotid atherosclerosis in patients with never treated essential hypertension.
abstract: BACKGROUND
  Wall shear stress (WSS) has been shown to be a critical determinant of vessel diameter implicated in vascular remodeling and atherogenesis. Carotid intima-media thickness (IMT), resistive index (RI), and pulsatility index (PI) have been used as relevant indictors for carotid atherosclerosis. The study aimed to investigate the relationship between hemodynamic parameters in the common carotid artery (CCA) and the severity of carotid atherosclerosis in untreated hypertensive patients.
  
  
  METHODS
  Duplex ultrasound was performed in 64 untreated hypertensive patients and 16 age-matched normotensive control subjects. Morphologic and hemodynamic parameters of CCA, including peak and mean WSS, RI, PI, and IMT were calculated after measuring internal diameter (ID) and flow velocity of CCA.
  
  
  RESULTS
  Subjects with hypertension had lower peak and mean WSS than did normotensive control subjects (P < 0.05). Both carotid RI and PI were found to correlate inversely with mean WSS in hypertensive subjects. There was no correlation between carotid IMT and WSS. Stepwise multiple regression analysis for carotid RI and PI after adjustment for age, carotid IMT, and high sensitivity C-reactive protein (hsCRP) showed that mean WSS was an independent determinant of RI and PI.
  
  
  CONCLUSIONS
  High carotid atherosclerotic indexes as expressed by both RI and PI are associated with low WSS in CCA. These findings indicate that local shear stress is associated with altered vascular pulsatility and resistance. Consequent alteration in local vascular dynamics could be an underlying mechanism for the progression of atherosclerosis.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kaohsiung Municipal United Hospital, Kaohsiung, Taiwan.
authors.forename: Min-Yi
authors.initials: MY
authors.lastname: Lee
authors.forename: Chan-Ming
authors.initials: CM
authors.lastname: Wu
authors.forename: Kuo-Ho
authors.initials: KH
authors.lastname: Yu
authors.forename: Chih-Sheng
authors.initials: CS
authors.lastname: Chu
authors.forename: Kun-Tai
authors.initials: KT
authors.lastname: Lee
authors.forename: Sheng-Hsiung
authors.initials: SH
authors.lastname: Sheu
authors.forename: Wen-Ter
authors.initials: WT
authors.lastname: Lai
mesh_terms: D000368:Aged; D001916:Brachial Artery / Q000503:physiopathology; D002340:Carotid Artery Diseases / Q000209:etiology / Q000503:physiopathology*; D017536:Carotid Artery, Common / Q000503:physiopathology*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow; D012044:Regression Analysis; D013314:Stress, Mechanical