title: Withdrawal of hormonal therapy for 4 weeks decreases arterial compliance in postmenopausal women.
abstract: BACKGROUND
  We demonstrated in a previous cross-sectional study that arterial compliance is elevated in postmenopausal women taking estrogen-containing hormonal therapy, which may partially account for the reduction in cardiovascular risk observed.
  
  
  OBJECTIVE
  To investigate the effects of withdrawal and recommencement of hormonal therapy, each for 4 weeks, on arterial compliance.
  
  
  METHODS
  Seventeen postmenopausal women [aged 56 +/- 4 years (mean +/- SD)] taking long-term hormonal therapy (+HT group) were studied at baseline, 4 weeks after withdrawal of hormonal therapy and again 4 weeks after recommencement. Systemic arterial compliance (SAC), pulse wave velocity (PWV) in the aorto-femoral and femoral-dorsalis pedis regions, and hemodynamic variables were measured at baseline, and at the end of each study intervention. As a time-control, seventeen postmenopausal women (aged 63 +/- 7 years) not taking hormonal therapy (-HT group) were also investigated.
  
  
  RESULTS
  SAC significantly decreased from 0.47 +/- 0.06 to 0.40 +/- 0.05 arbitrary compliance units (mean +/- SEM; P < 0.05) after 4 weeks withdrawal from hormonal therapy. PWV in the femoral-dorsalis pedis region was elevated significantly by the withdrawal of hormonal therapy (8.4 +/- 0.4 to 9.4 +/- 0.5 m/s; P < 0.05), but PWV in the aortofemoral region did not change. After therapy had been recommenced for 4 weeks, SAC and PWV in the femoral-dorsalis pedis region were restored to baseline values. The -HT group showed no difference in SAC or PWV, and mean arterial pressure did not change in either group throughout the study period.
  
  
  CONCLUSIONS
  These data suggest that hormonal modulation of distal arterial vascular tone may account for short-term changes in arterial compliance associated with estrogen-containing hormonal therapy.
authors: Alfred and Baker Medical Unit, Baker Medical Research Institute, Melbourne, Australia.
authors: T K
authors: TK
authors: Waddell
authors: C
authors: C
authors: Rajkumar
authors: J D
authors: JD
authors: Cameron
authors: G L
authors: GL
authors: Jennings
authors: A M
authors: AM
authors: Dart
authors: B A
authors: BA
authors: Kingwell
mesh_terms: D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000502:physiology; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003187:Compliance; D004967:Estrogens / Q000009:adverse effects*; D005260:Female; D005263:Femoral Artery / Q000502:physiology; D005500:Follow-Up Studies; D020249:Hormone Replacement Therapy / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000187:drug effects / Q000502:physiology*; D018616:Ultrasonography, Doppler, Duplex; D014655:Vascular Resistance / Q000187:drug effects*
chemical_list: D004967:Estrogens