title: Impaired cerebral autoregulation is associated with vasospasm and delayed cerebral ischemia in subarachnoid hemorrhage.
abstract: OBJECTIVE
  Cerebral autoregulation may be impaired in the early days after subarachnoid hemorrhage (SAH). The purpose of this study was to examine the relationship between cerebral autoregulation and angiographic vasospasm (aVSP) and radiographic delayed cerebral ischemia (DCI) in patients with SAH.
  
  
  METHODS
  Sixty-eight patients (54±13 years) with a diagnosis of nontraumatic SAH were studied. Dynamic cerebral autoregulation was assessed using transfer function analysis (phase and gain) of the spontaneous blood pressure and blood flow velocity oscillations on days 2 to 4 post-SAH. aVSP was diagnosed using a 4-vessel conventional angiogram. DCI was diagnosed from CT. Decision tree models were used to identify optimal cut-off points for clinical and physiological predictors of aVSP and DCI. Multivariate logistic regression models were used to develop and validate a risk scoring tool for each outcome.
  
  
  RESULTS
  Sixty-two percent of patients developed aVSP, and 19% developed DCI. Patients with aVSP had higher transfer function gain (1.06±0.33 versus 0.89±0.30; P=0.04) and patients with DCI had lower transfer function phase (17.5±39.6 versus 38.3±18.2; P=0.03) compared with those who did not develop either. Multivariable scoring tools using transfer function gain>0.98 and phase<12.5 were strongly predictive of aVSP (92% positive predictive value; 77% negative predictive value; area under the receiver operating characteristic curve, 0.92) and DCI (80% positive predictive value; 91% negative predictive value; area under the curve, 0.94), respectively.
  
  
  CONCLUSIONS
  Dynamic cerebral autoregulation is impaired in the early days after SAH. Including autoregulation as part of the initial clinical and radiographic assessment may enhance our ability to identify patients at a high risk for developing secondary complications after SAH.
authors.affiliation: From the Department of Neurology, Stroke Division (F.O., S.M., A.M., S.C., S.O., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory and Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Institute for Aging Research, Hebrew SeniorLife, Roslindale, MA (S.P.); Harvard Medical School, Boston, MA (F.O., C.O.T., A.A.Z., A.M., S.C., S.O., S.P., R.D., F.A.S.); Department of Neurology, Klinikum Worms, Teaching Hospital of Mainz, Germany (S.M.); and Division of Neuroimaging and Neurointervention, Department of Radiology, University of Massachusetts Medical Center, Worcester, MA (A.P.).
authors.forename: Fadar
authors.initials: F
authors.lastname: Otite
authors.forename: Susanne
authors.initials: S
authors.lastname: Mink
authors.forename: Can Ozan
authors.initials: CO
authors.lastname: Tan
authors.forename: Ajit
authors.initials: A
authors.lastname: Puri
authors.forename: Amir A
authors.initials: AA
authors.lastname: Zamani
authors.forename: Aujan
authors.initials: A
authors.lastname: Mehregan
authors.forename: Sherry
authors.initials: S
authors.lastname: Chou
authors.forename: Susannah
authors.initials: S
authors.lastname: Orzell
authors.forename: Sushmita
authors.initials: S
authors.lastname: Purkayastha
authors.forename: Rose
authors.initials: R
authors.lastname: Du
authors.forename: Farzaneh A
authors.initials: FA
authors.lastname: Sorond
mesh_terms: D000367:Age Factors; D000368:Aged; D019540:Area Under Curve; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011237:Predictive Value of Tests; D012372:ROC Curve; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017585:Ultrasonography, Doppler, Transcranial; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*
keywords: cerebrovascular circulation; subarachnoid hemorrhage; ultrasonography, Doppler