title: External counterpulsation augments blood pressure and cerebral flow velocities in ischemic stroke patients with cerebral intracranial large artery occlusive disease.
abstract: OBJECTIVE
  External counterpulsation (ECP) is a novel noninvasive method used to improve the perfusion of vital organs, which may benefit ischemic stroke patients. We hypothesized that ECP may augment cerebral blood flow of ischemic stroke patients via induced hypertension.
  
  
  METHODS
  We recruited ischemic stroke patients with cerebral intracranial large artery occlusive disease and healthy elderly controls into this study. Bilateral middle cerebral arteries of subjects were monitored using transcranial Doppler. Flow velocity changes before, during, and after ECP were, respectively, recorded for 3 minutes while continuous beat-to-beat blood pressure data were recorded. Cerebral augmentation index was the increase in percentage of middle cerebral artery mean flow velocity during ECP compared with baseline. Transcranial Doppler data were analyzed based on ipsilateral or contralateral to the infarct side.
  
  
  RESULTS
  ECP significantly increased mean blood pressure of stroke patients and controls. During ECP, middle cerebral artery mean flow velocities of stroke patients increased on both ipsilateral and contralateral sides when compared with baseline (ipsilateral cerebral augmentation index, 9.64%; contralateral cerebral augmentation index, 9%; both P<0.001), but there was no increase in difference between the 2 sides when compared with each other. Mean flow velocities of controls did not change under ECP. After ECP, blood pressure and flow velocity of stroke patients returned to baseline level.
  
  
  CONCLUSIONS
  ECP provides a new method of cerebral blood flow augmentation in ischemic stroke by elevation of blood pressure. Flow augmentation induced by ECP suggests the improvement of cerebral perfusion and collateral supply from infarct ipsilateral and contralateral sides.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Sha Tin, Hong Kong SAR.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Lin
authors.forename: Li
authors.initials: L
authors.lastname: Xiong
authors.forename: Jinghao
authors.initials: J
authors.lastname: Han
authors.forename: Thomas Wai Hong
authors.initials: TW
authors.lastname: Leung
authors.forename: Yannie Oi Yan
authors.initials: YO
authors.lastname: Soo
authors.forename: Xiangyan
authors.initials: X
authors.lastname: Chen
authors.forename: Ka Sing Lawrence
authors.initials: KS
authors.lastname: Wong
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D015908:Counterpulsation; D005260:Female; D006801:Humans; D008297:Male; D020521:Stroke / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D017585:Ultrasonography, Doppler, Transcranial