title: Major impact of body position on arterial stiffness indices derived from radial applanation tonometry in pregnant and nonpregnant women.
abstract: OBJECTIVE
  To evaluate the impact of body position on the arterial stiffness indices provided by radial applanation tonometry in pregnant and nonpregnant women.
  
  
  METHODS
  Twenty-four young women (18-30 years) in the third trimester of a normal pregnancy and 20 healthy nonpregnant women of the same age were enrolled. In each, applanation tonometry was carried out in the sitting and supine position. The following stiffness indices were analyzed: systolic augmentation index (sAix), sAix adjusted for heart rate (sAix@75) and diastolic augmentation index (dAix), all expressed in % of central aortic pulse pressure.
  
  
  RESULTS
  The sAix was apparently not influenced by body position, but the transition from seated to supine was associated with a substantial decrease in heart rate. When correcting for this confounder by calculating the sAix@75, systolic augmentation was substantially lower when individuals were supine (mean ± SD: nonpregnant 3.0 ± 14.4%, pregnant 8.8 ± 9.7%) than when they were sitting (nonpregnant 5.7 ± 13.0%, pregnant 11.1 ± 83%, P = 0.005 supine vs. seated in both study groups, P > 0.2 for pregnant vs. nonpregnant). The influence of body position on the dAix went in the opposite direction (supine: nonpregnant 9.7 ± 6.6%, pregnant 4.4 ± 3.5%; seated: nonpregnant 7.7 ± 5.8%, pregnant 3.3 ± 2.4%, P < 0.00001 supine vs. seated in both study groups, P = 0.001 for pregnant vs. nonpregnant).
  
  
  CONCLUSIONS
  Body position has a major impact on the pattern of central aortic pressure augmentation by reflected waves in healthy young women examined either during third trimester pregnancy or in the nonpregnant state.
authors.affiliation: Division de Physiopathologie Clinique, Département de Médecine, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, Switzerland.
authors.forename: Letitia
authors.initials: L
authors.lastname: Jaccoud
authors.forename: Corina
authors.initials: C
authors.lastname: Rotaru
authors.forename: Abigaël
authors.initials: A
authors.lastname: Heim
authors.forename: Lucas
authors.initials: L
authors.lastname: Liaudet
authors.forename: Bernard
authors.initials: B
authors.lastname: Waeber
authors.forename: Patrick
authors.initials: P
authors.lastname: Hohlfeld
authors.forename: François
authors.initials: F
authors.lastname: Feihl
mesh_terms: D001158:Arteries / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008365:Manometry; D011187:Posture; D011247:Pregnancy