title: Cerebral hemodynamics and cognitive impairment: baseline data from the RECON trial.
abstract: OBJECTIVE
  To determine whether unihemispheral hemodynamic failure is independently associated with cognitive impairment among participants in the National Institute of Neurological Disorders and Stroke-sponsored, multicenter, randomized clinical trial, Randomized Evaluation of Carotid Occlusion and Neurocognition (RECON).
  
  
  METHODS
  Forty-three patients were randomized into RECON after recent symptomatic carotid artery occlusion and asymmetrically increased oxygen extraction fraction (OEF) by PET (OEF ratio >1.13), indicating stage II hemodynamic failure on the side of occlusion. The PET-positive patients were compared with 28 RECON-enrolled patients who met all clinical and radiographic inclusion/exclusion criteria but had no OEF asymmetry. A multivariable regression compared patients with PET OEF >1.13 or ≤1.13, stratifying by TIA vs. stroke as the qualifying event. The dependent variable was a composite neurocognitive score derived from averaging age-normalized z scores on a test battery that included global and internal carotid artery (ICA) side-relevant hemisphere-specific tests.
  
  
  RESULTS
  There were no differences in demographic, clinical, or radiologic characteristics between the PET-positive and PET-negative patients except for PET OEF asymmetry. The unadjusted average neurocognitive z score was -1.45 for the PET-positive and -1.25 for the PET-negative patients, indicating cognitive impairment in both groups but no difference between them (p = 0.641). After adjustment for age, education, side of occlusion, depression, and previous stroke, there was a significant difference between PET-positive and PET-negative patients among those with TIA as a qualifying event (average z score = -1.41 vs. -0.76, p = 0.040). Older age and right ICA side were also significant in this model.
  
  
  CONCLUSIONS
  Hemodynamic failure is independently associated with cognitive impairment in patients with carotid occlusion. This finding establishes the physiologic parameter upon which the extracranial-intracranial bypass will be tested.
authors.affiliation: Columbia University Medical Center, New York, NY, USA. rsm2@columbia.edu
authors.forename: R S
authors.initials: RS
authors.lastname: Marshall
authors.forename: J R
authors.initials: JR
authors.lastname: Festa
authors.forename: Y K
authors.initials: YK
authors.lastname: Cheung
authors.forename: R
authors.initials: R
authors.lastname: Chen
authors.forename: M A
authors.initials: MA
authors.lastname: Pavol
authors.forename: C P
authors.initials: CP
authors.lastname: Derdeyn
authors.forename: W R
authors.initials: WR
authors.lastname: Clarke
authors.forename: T O
authors.initials: TO
authors.lastname: Videen
authors.forename: R L
authors.initials: RL
authors.lastname: Grubb
authors.forename: H P
authors.initials: HP
authors.lastname: Adams
authors.forename: W J
authors.initials: WJ
authors.lastname: Powers
authors.forename: R M
authors.initials: RM
authors.lastname: Lazar
mesh_terms: D000368:Aged; D002340:Carotid Artery Diseases / Q000150:complications / Q000503:physiopathology / Q000523:psychology; D002560:Cerebrovascular Circulation; D003072:Cognition Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000523:psychology*; D015331:Cohort Studies; D004522:Educational Status; D005260:Female; D007839:Functional Laterality; D006801:Humans; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000523:psychology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography; D020521:Stroke / Q000150:complications / Q000000981:diagnostic imaging / Q000523:psychology; D014145:Trail Making Test; D014796:Visual Perception; D014936:Word Association Tests