title: Reflected rather than forward wave pressures account for brachial pressure-independent relations between aortic pressure and end-organ changes in an African community.
abstract: OBJECTIVE
  To determine whether brachial blood pressure (BP)-independent relations between aortic pressure and cardiovascular damage are better explained by reflected (backward) (Pb) or forward (Pf) wave pressure effects.
  
  
  METHODS
  In 1174 participants from a community of African ancestry, we assessed central aortic pulse pressure (PPc), Pb, and Pf (radial applanation tonometry, SphygmoCor) as well as left ventricular mass index (LVMI) (n = 786), aortic pulse wave velocity (PWV) (n = 1019), carotid intima-media thickness (IMT) (n = 578), transmitral early-to-late left ventricular diastolic velocity (E/A) (n = 779) and estimated glomerular filtration rate (eGFR) (n = 1174).
  
  
  RESULTS
  Independent of mean arterial pressure and confounders, PPc, and both Pb and Pf were associated with end-organ measures or damage (P < 0.05 to P < 0.0001). With adjustments for brachial PP and confounders, Pb remained directly associated with LVMI (partial r = 0.09, P < 0.01), PWV (partial r = 0.28, P < 0.0001), and IMT (partial r = 0.28, P < 0.0001), and inversely associated with E/A (partial r = -0.31, P < 0.0001) and eGFR (partial r = -0.14, P < 0.0001). Similar relations were noted with the presence of end-organ damage (P < 0.05 to P < 0.0001). In contrast, with adjustments for brachial PP and confounders, Pf no longer retained direct relations with LVMI, PWV, and IMT or inverse relations with E/A and eGFR. Adjustments for Pb, but not Pf, diminished brachial PP-independent relationships between PPc and end-organ measures. Independent relations between Pb, but not Pf and end-organ measures, were largely attributed to Pb accounting for most of the variation in brachial-to-aortic PP amplification.
  
  
  CONCLUSIONS
  In communities of African ancestry, brachial BP-independent relations between aortic pressure and end-organ changes are largely attributed to an impact of reflected rather than forward wave pressures.
authors.affiliation: aCardiovascular Pathophysiology and Genomics Research Unit, Schools of Physiology bMedicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa *Moekanyi J. Sibiya, Angela J. Woodiwiss and Gavin R. Norton contributed equally to this work.
authors.forename: Moekanyi J
authors.initials: MJ
authors.lastname: Sibiya
authors.forename: Angela J
authors.initials: AJ
authors.lastname: Woodiwiss
authors.forename: Hendrik L
authors.initials: HL
authors.lastname: Booysen
authors.forename: Andrew
authors.initials: A
authors.lastname: Raymond
authors.forename: Aletta M E
authors.initials: AM
authors.lastname: Millen
authors.forename: Muzi J
authors.initials: MJ
authors.lastname: Maseko
authors.forename: Olebogeng H I
authors.initials: OH
authors.lastname: Majane
authors.forename: Pinhas
authors.initials: P
authors.lastname: Sareli
authors.forename: Elena
authors.initials: E
authors.lastname: Libhaber
authors.forename: Gavin R
authors.initials: GR
authors.lastname: Norton
mesh_terms: D000328:Adult; D001011:Aorta / Q000502:physiology*; D062186:Arterial Pressure / Q000502:physiology*; D044383:Black People; D001795:Blood Pressure Determination; D001916:Brachial Artery / Q000502:physiology*; D059168:Carotid Intima-Media Thickness; D005260:Female; D005919:Glomerular Filtration Rate; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D063177:Pulse Wave Analysis / Q000379:methods*