title: Cerebral hemodynamic characteristics of acute mountain sickness upon acute high-altitude exposure at 3,700 m in young Chinese men.
abstract: OBJECTIVE
  We aimed at identifying the cerebral hemodynamic characteristics of acute mountain sickness (AMS).
  
  
  METHODS
  Transcranial Doppler (TCD) sonography examinations were performed between 18 and 24 h after arrival at 3,700 m via plane from 500 m (n = 454). A subgroup of 151 subjects received TCD examinations at both altitudes.
  
  
  RESULTS
  The velocities of the middle cerebral artery, vertebral artery (VA) and basilar artery (BA) increased while the pulsatility indexes (PIs) and resistance indexes (RIs) decreased significantly (all p < 0.05). Velocities of BA were higher in AMS (AMS+) individuals when compared with non-AMS (AMS-) subjects (systolic velocity: 66 ± 12 vs. 69 ± 15 cm/s, diastolic velocity: 29 ± 7 vs. 31 ± 8 cm/s and mean velocity, 42 ± 9 vs. 44 ± 10 cm/s). AMS was characterized by higher diastolic velocity [V d_VA (26 ± 4 vs. 25 ± 4, p = 0.013)] with lower PI and RI (both p = 0.004) in VA. Furthermore, the asymmetry index (AI) of VAs was significantly lower in the AMS + group [-5.7 % (21.0 %) vs. -2.5 % (17.8 %), p = 0.016]. The AMS score was closely correlated with the hemodynamic parameters of BA and the V d_VA, PI, RI and AI of VA.
  
  
  CONCLUSIONS
  AMS is associated with alterations in cerebral hemodynamics in the posterior circulation rather than the anterior one, and is characterized by higher blood velocity with lower resistance. In addition, the asymmetry of VAs may be involved in AMS.
authors.affiliation: Department of Cardiology, Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037, China, bianshizhu@163.com.
authors.forename: Shi-Zhu
authors.initials: SZ
authors.lastname: Bian
authors.forename: Jun
authors.initials: J
authors.lastname: Jin
authors.forename: Qian-Ning
authors.initials: QN
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Qin
authors.forename: Ji-Hang
authors.initials: JH
authors.lastname: Zhang
authors.forename: Shi-Yong
authors.initials: SY
authors.lastname: Yu
authors.forename: Jian-Fei
authors.initials: JF
authors.lastname: Chen
authors.forename: Cai-Fa
authors.initials: CF
authors.lastname: Tang
authors.forename: Lan
authors.initials: L
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000531:Altitude; D000532:Altitude Sickness / Q000503:physiopathology*; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged