title: Distribution of cardiac output to the brain across the adult lifespan.
abstract: A widely accepted dogma is that about 15-20% of cardiac output is received by the brain in healthy adults under resting conditions. However, it is unclear if the distribution of cardiac output directed to the brain alters across the adult lifespan and is modulated by sex or other hemodynamic variables. We measured cerebral blood flow/cardiac output ratio index in 139 subjects (88 women, age 21-80 years) using phase-contrast magnetic resonance imaging and echocardiography. Body mass index, cardiac systolic function (eject fraction), central arterial stiffness (carotid-femoral pulse wave velocity), arterial pressure, heart rate, physical fitness (VO2max), and total brain volume were measured to assess their effects on the cardiac output-cerebral blood flow relationship. Cerebral blood flow/cardiac output ratio index decreased by 1.3% per decade associated with decreases in cerebral blood flow ( P < 0.001), while cardiac output remained unchanged. Women had higher cerebral blood flow, lower cardiac output, and thus higher cerebral blood flow/cardiac output ratio index than men across the adult lifespan. Age, body mass index, carotid-femoral pulse wave velocity, and arterial pressure all had negative correlations with cerebral blood flow and cerebral blood flow/cardiac output ratio index ( P < 0.05). Multivariable analysis adjusted for sex, age showed that only body mass index was negatively associated with cerebral blood flow/cardiac output ratio index (β = -0.33, P < 0.001). These findings demonstrated that cardiac output distributed to the brain has sex differences and decreases across the adult lifespan and is inversely associated with body mass index.
authors: 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA.|2 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA.|3 Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.
authors: Chang-Yang
authors: CY
authors: Xing
authors: 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA.|2 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA.
authors: Takashi
authors: T
authors: Tarumi
authors: 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA.|2 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA.|3 Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.
authors: Jie
authors: J
authors: Liu
authors: 4 Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, USA.
authors: Yinan
authors: Y
authors: Zhang
authors: 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA.
authors: Marcel
authors: M
authors: Turner
authors: 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA.
authors: Jonathan
authors: J
authors: Riley
authors: 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA.
authors: Cynthia Duron
authors: CD
authors: Tinajero
authors: 3 Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi'an, China.
authors: Li-Jun
authors: LJ
authors: Yuan
authors: 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA.|2 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA.|4 Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, USA.
authors: Rong
authors: R
authors: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology*; D015992:Body Mass Index; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging*; D002302:Cardiac Output / Q000502:physiology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D055815:Young Adult
keywords: Aging; cerebral blood flow; hemodynamics; imaging; magnetic resonance imaging