title: Use of short-radius centrifugation to augment ankle-brachial indices.
abstract: BACKGROUND
  Peripheral arterial disease is mainly caused by atherosclerosis and is characterized by decreased circulation, lower blood pressure, and insufficient tissue perfusion in the lower extremities. The hemodynamics of standing and altered gravity environments have been well studied relative to arm blood pressures but are less well understood for ankle pressures.
  
  
  METHODS
  Because regional blood pressure depends, in part, on the gravitational pressure gradient, we hypothesized that artificial gravity exposure on a short-arm centrifuge with the center of rotation above the head would increase blood pressure in the lower extremities. Cardiovascular parameters for 12 healthy subjects were measured during exposure to supine short-arm centrifugation at 20, 25, and 30 revolutions per minute (rpm), corresponding to centripetal accelerations of 0.94, 1.47, and 2.11 Gz at the foot level, respectively.
  
  
  RESULTS
  Systolic ankle blood pressure significantly increased at all levels of centrifugation. Ankle-brachial indices (the ratio of systolic ankle to arm blood pressures) increased significantly from 1.17 +/- 0.03 to 1.58 +/- 0.03 at 0.94 Gz (P < 0.005), 1.74 +/- 0.02 at 1.47 Gz (P < 0.005), and 1.89 +/- 0.06 at 2.11 Gz (P < 0.005). Systolic arm blood pressure significantly increased at 2.11 Gz, but heart rate did not change significantly. All parameters returned to normal after cessation of centrifugation.
  
  
  CONCLUSIONS
  We demonstrated that short-radius centrifugation leads to an increase in ankle-brachial indices. This could have potential implications for the treatment of peripheral arterial disease.
authors.affiliation: Department of Vascular Surgery, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada. smgrenon@gmail.com
authors.forename: S Marlene
authors.initials: SM
authors.lastname: Grenon
authors.forename: Jaime
authors.initials: J
authors.lastname: Mateus
authors.forename: York
authors.initials: Y
authors.lastname: Hsiang
authors.forename: Ravi
authors.initials: R
authors.lastname: Sidhu
authors.forename: Laurence
authors.initials: L
authors.lastname: Young
authors.forename: Joel
authors.initials: J
authors.lastname: Gagnon
mesh_terms: D000328:Adult; D055109:Ankle Brachial Index / Q000379:methods*; D001794:Blood Pressure; D002498:Centrifugation / Q000379:methods; D005260:Female; D018470:Gravity, Altered; D006801:Humans; D008297:Male; D008833:Microcirculation; D016491:Peripheral Vascular Diseases / Q000175:diagnosis* / Q000503:physiopathology