title: Cerebral Hemodynamics in the Elderly: A Transcranial Doppler Study in the Einstein Aging Study Cohort.
abstract: OBJECTIVE
  We sought to describe the relationship between age, sex, and race/ethnicity with transcranial Doppler hemodynamic characteristics from major intracerebral arterial segments in a large elderly population with varying demographics.
  
  
  METHODS
  We analyzed 369 stroke-free participants aged 70 years and older from the Einstein Aging Study. Single-gate, nonimaging transcranial Doppler sonography, a noninvasive sonographic technique that assesses real-time cerebrovascular hemodynamics, was used to interrogate 9 cerebral arterial segments. Individual Doppler spectra and cerebral blood flow velocities were acquired, and the pulsatility index and resistive index were calculated by the device's automated waveform-tracking function. Multiple linear regression models were used to examine the independent associations of age, sex, and race/ethnicity with transcranial Doppler measures, adjusting for hypertension, history of myocardial infarction or revascularization, and history of diabetes.
  
  
  RESULTS
  Among enrolled participants, 303 individuals had at least 1 vessel insonated (mean age [SD], 80 [6] years; 63% women; 58% white; and 32% black). With age, transcranial Doppler measures of mean blood flow velocity were significantly decreased in the basilar artery (P = .001) and posterior cerebral artery (right, P = .003; left, P = .02). Pulsatility indices increased in the left middle cerebral artery (P = .01) and left anterior cerebral artery (P = .03), and the resistive index was increased in the left middle cerebral artery (P = .007) with age. Women had higher pulsatility and resistive indices compared to men in several vessels.
  
  
  CONCLUSIONS
  We report a decreased mean blood flow velocity and weakly increased arterial pulsatility and resistance with aging in a large elderly stroke-free population. These referential trends in cerebrovascular hemodynamics may carry important implications in vascular diseases associated with advanced age, increased risk of cerebrovascular disease, cognitive decline, and dementia.
authors.affiliation: Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida USA.
authors.forename: Dixon
authors.initials: D
authors.lastname: Yang
authors.affiliation: Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida USA.
authors.forename: Digna
authors.initials: D
authors.lastname: Cabral
authors.affiliation: Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York USA.
authors.forename: Emmanuel N
authors.initials: EN
authors.lastname: Gaspard
authors.affiliation: Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York USA, Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Lipton
authors.affiliation: Department of Neurology, Miller School of Medicine, University of Miami, Miami, Florida USA.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Rundek
authors.affiliation: Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York USA, Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York USA carol.derby@einstein.yu.edu.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Derby
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002550:Cerebral Veins / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D015331:Cohort Studies; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D015577:Geriatric Assessment / Q000379:methods* / Q000706:statistics & numerical data; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D044469:Racial Groups / Q000706:statistics & numerical data; D012737:Sex Factors; D017585:Ultrasonography, Doppler, Transcranial
keywords: aging; blood flow velocities; cerebral hemodynamics; head and neck ultrasound; pulsatiliy index; resistive index; transcranial Doppler sonography