title: Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude.
abstract: To assess racial, sexual, and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = QICA + QVA), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and QVA/TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation, and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (-17% vs. 0%), TCVR (22% vs. 12%), TCOD (0% vs. 10%) and QVA/TCBF (0% vs. 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution.
authors: Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors: Jie
authors: J
authors: Liu
authors: Department of Cardiovascular Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors: Yang
authors: Y
authors: Liu
authors: General Hospital of Tibet Military Area Command, Lhasa, Tibet Autonomous Region, China.
authors: Li-Hua
authors: LH
authors: Ren
authors: Department of Ultrasonic Medicine, Affiliated Hospital of Tibet University for Nationalities, Xianyang, Shaanxi, China.
authors: Li
authors: L
authors: Li
authors: Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors: Zhen
authors: Z
authors: Wang
authors: Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors: Shan-Shan
authors: SS
authors: Liu
authors: General Hospital of Tibet Military Area Command, Lhasa, Tibet Autonomous Region, China.
authors: Su-Zhi
authors: SZ
authors: Li
authors: Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors: Tie-Sheng
authors: TS
authors: Cao
mesh_terms: D000531:Altitude; D000704:Analysis of Variance; D044466:Asian People; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003710:Demography; D005006:Ethnicity; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D044469:Racial Groups; D012727:Sex Characteristics; D014463:Ultrasonography; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen