title: Central pulse wave velocity is responsible for increased brachial-ankle pulse wave velocity in subclinical hypothyroidism.
abstract: OBJECTIVE
  Subclinical hypothyroidism affects 5-15% of the general population, and is associated with increased morbidity from cardiovascular disease. We recently reported a significant increase in brachial-ankle pulse wave velocity (baPWV), a parameter of arterial stiffening and an independent predictor for the presence of cardiovascular disease, in subclinical hypothyroidism. The current study was performed to assess which arterial segment is responsible for enhanced baPWV in subclinical hypothyroidism.
  
  
  METHODS
  Central PWV (PWV in heart-femoral segments), peripheral PWV (PWV in femoral-ankle segments), and baPWV were measured in subclinical hypothyroid patients and normal subjects.
  
  
  RESULTS
  Central PWV, baPWV, and peripheral PWV were significantly higher in subclinical hypothyroid patients than in normal subjects. BaPWV was significantly and positively correlated with central and peripheral PWV in both groups. However, a significant and positive correlation between central and peripheral PWV in normal subjects was not found in subclinical hypothyroid patients. Moreover, stepwise regression analysis showed that the association of central PWV with baPWV was stronger than that of peripheral PWV, whereas in normal subjects central PWV was not associated with baPWV.
  
  
  CONCLUSIONS
  Our results demonstrate that central and peripheral PWV are significantly higher in subclinical hypothyroid patients, and that the increase in baPWV depends more strongly on central PWV than on peripheral PWV in these patients. This suggests that increased elastic arterial stiffening of the aorta, rather than of peripheral muscular arteries, might be more responsible for increased general arterial stiffening in subclinical hypothyroid patients.
authors.affiliation: Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of Medicine, 1-4-3, Asahi-Machi, Osaka, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Nagasaki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Inaba
authors.forename: Yasuro
authors.initials: Y
authors.lastname: Kumeda
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Hiura
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Yamada
authors.forename: Kumi
authors.initials: K
authors.lastname: Shirakawa
authors.forename: Eiji
authors.initials: E
authors.lastname: Ishimura
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nishizawa
mesh_terms: D000842:Ankle; D001011:Aorta / Q000503:physiopathology; D001783:Blood Flow Velocity; D001795:Blood Pressure Determination; D001916:Brachial Artery / Q000503:physiopathology*; D016022:Case-Control Studies; D004562:Electrocardiography; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology; D006801:Humans; D007037:Hypothyroidism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011673:Pulsatile Flow; D011674:Pulse; D012044:Regression Analysis