title: Intentional hypertension during dissection of carotid arteries in endarterectomy prevents postoperative development of new cerebral ischemic lesions caused by intraoperative microemboli.
abstract: BACKGROUND
  Low blood flow velocity in the middle cerebral artery (MCA) correlates with the development of postoperative cerebral ischemic lesions related to generation of microemboli during dissection of carotid arteries in carotid endarterectomy (CEA).
  
  
  OBJECTIVE
  The purpose of this prospectively controlled trial was to determine whether increased mean blood flow velocity in the MCA by intentional hypertension during carotid dissection in CEA prevented postoperative development of new cerebral ischemic lesions caused by intraoperative microemboli.
  
  
  METHODS
  Patients with ipsilateral internal carotid artery stenosis (>70%) underwent CEA under transcranial Doppler monitoring of mean blood flow velocity and microembolic signals in the ipsilateral MCA. Attempts were made to keep systolic blood pressure during carotid dissection between -10% and +10% of the preoperative value (controls, n = 65) or above a +10% increase (intentional hypertension group, n = 65).
  
  
  RESULTS
  Incidence of new ischemic lesions on postoperative diffusion-weighted magnetic resonance imaging was significantly lower in the intentional hypertension group both for all patients (controls, 15.4%; intentional hypertension group, 3.1%; P = .03) and in a subgroup of 37 patients showing microembolic signals during carotid dissection (controls, 52.6%; intentional hypertension group, 11.1%; P = .013). Logistic regression analysis demonstrated the absence of intentional hyperperfusion (95% confidence interval: 1.77-100.00; P = .012) and high number of microembolic signals (95% confidence interval: 1.00-1.62; P = .05) during carotid dissection were significant independent predictors of the postoperative development of new ischemic lesions on diffusion-weighted magnetic resonance imaging.
  
  
  CONCLUSIONS
  Increased MCA mean blood flow velocity by intentional hypertension during dissection of the carotid artery in CEA prevents the postoperative development of new cerebral ischemic lesions caused by intraoperative microemboli.
authors.affiliation: Department of Neurosurgery, Iwate Medical University, Morioka, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Ogasawara
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoshida
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kuroda
authors.forename: Taro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Kubo
authors.forename: Shunrou
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Akira
authors.initials: A
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology*; D001921:Brain / Q000098:blood supply; D002545:Brain Ischemia / Q000209:etiology / Q000517:prevention & control*; D016893:Carotid Stenosis / Q000601:surgery*; D002560:Cerebrovascular Circulation / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D016894:Endarterectomy, Carotid / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D006973:Hypertension; D020766:Intracranial Embolism / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000517:prevention & control*; D017585:Ultrasonography, Doppler, Transcranial