title: Effects of gravity-induced upper-limb blood pressure changes on wave transmission and arterial radial waveform.
abstract: Local blood pressure (BP) changes induced by arm tilting may influence pressure wave transmission and reflection. We investigated the effects of upper-limb tilting on radial augmentation index (rAIx) and related central measures [aortic augmentation index (aAIx)].
  
  
  
  In 45 volunteers (age 49 ± 19 years), supine brachial BP and radial artery waveforms were obtained by applanation tonometry with the dominant arm stretched and gently supported in three different positions: at the heart level, with the BP cuff 15 cm above heart level (approximately +30°), and 15 cm below heart level (-30°).
  
  
  
  Brachial SBP/DBP was 120/68 ± 17/8 mmHg. Mean arterial pressure changed predictably with arm tilting (99 ± 12 mmHg at -30°, 88 ± 10 mmHg at 0°, 77 ± 11 mmHg at +30°, all P < 0.001). rAIx decreased at -30° (69 ± 22%), and increased at +30° (93 ± 20%) compared with 0° (82 ± 20%, all P less than 0.001). Changes in rAIx (value at +30° minus value at -30°) showed an inverse relationship with age (r = -0.32, P = 0.03). Heart rate, BP and rAIx did not change in the contralateral arm, which was held at the heart level during the examination. aAIx followed the same pattern as rAIx (123 ± 27% at -30°, 144 ± 33% at +30°, 136 ± 31% at 0°, all P less than 0.001); changes in rAIx and aAIx were strongly related each other (r = 0.82, P < 0.001).
  
  
  
  Acute gravitational upper-limb BP changes generate opposite, profound changes in rAIx, and major artifactual changes in aAIx. These findings provide a rationale for recommending to keep the upper limb at the heart level during radial waveform assessment.
authors.affiliation: aDipartimento di Medicina, Università degli Studi di Perugia, Perugia bUnità di Medicina Interna, Azienda Ospedaliero-Universitaria di Terni, Terni, Italy cYazmonit Ltd., Eshtaol, Israel dFaculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Pucci
authors.forename: Francesca
authors.initials: F
authors.lastname: Battista
authors.forename: Fabio
authors.initials: F
authors.lastname: Anastasio
authors.forename: Leandro
authors.initials: L
authors.lastname: Sanesi
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gavish
authors.forename: Mark
authors.initials: M
authors.lastname: Butlin
authors.forename: Alberto
authors.initials: A
authors.lastname: Avolio
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Schillaci
mesh_terms: D000328:Adult; D000368:Aged; D062186:Arterial Pressure; D001795:Blood Pressure Determination / Q000379:methods*; D001916:Brachial Artery / Q000502:physiology*; D005260:Female; D006112:Gravitation; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture; D063177:Pulse Wave Analysis; D017534:Radial Artery / Q000502:physiology*; D034941:Upper Extremity / Q000502:physiology*; D055815:Young Adult