title: Impaired cerebral autoregulation distal to carotid stenosis/occlusion is associated with increased risk of stroke at cardiac surgery with cardiopulmonary bypass.
abstract: OBJECTIVE
  Severe carotid stenosis and occlusion are associated with an increased risk of stroke during and after cardiac surgery with cardiopulmonary bypass. Relevance of an impaired cerebral autoregulation caused by stenosis/occlusion is unknown.
  
  
  METHODS
  We prospectively assessed the incidence of stroke in relation to severity of carotid disease and corresponding autoregulatory reserve in 2797 patients who had coronary artery bypass graft and/or valve surgery with cardiopulmonary bypass. Patients underwent preoperative carotid sonography and, in case of severe extracranial disease, transcranial Doppler sonography with carbon dioxide stimulation to assess cerebrovascular reserve capacity.
  
  
  RESULTS
  Sixty-seven (2.4%) patients had an ischemic stroke, which was fatal in 5. Anterior hemispheric stroke occurred in 42 (1.9%) patients with no/low-grade stenosis, 6 (1.8%) with medium-grade stenosis, 1 (0.6%) with high-grade stenosis/occlusion and normal autoregulation, and 3 (27.3%) with high-grade stenosis/occlusion and exhausted autoregulatory reserve. Increased risk was observed in patients with high-grade stenosis/occlusion and exhausted autoregulatory reserve also after adjustment for potential confounders (adjusted odds ratio [OR] 28.3, 95% confidence interval [CI] 5.8-139.1). Stroke risk was not increased in patients with stenosis/occlusion and normal autoregulation (1.5%, adjusted OR 0.6, 95% CI 0.2-1.6).
  
  
  CONCLUSIONS
  Cerebrovascular reserve capacity evaluated by preoperative transcranial Doppler carbon dioxide testing is a major determinant of stroke risk in patients with carotid artery stenosis/occlusion undergoing cardiac surgery with cardiopulmonary bypass. Its assessment facilitates identification of patients with an excess perioperative stroke risk.
authors.affiliation: Department of Neurology, University of Magdeburg, Magdeburg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Schoof
authors.forename: Wiebke
authors.initials: W
authors.lastname: Lubahn
authors.forename: Matthias
authors.initials: M
authors.lastname: Baeumer
authors.forename: Regina
authors.initials: R
authors.lastname: Kross
authors.forename: Claus-Werner
authors.initials: CW
authors.lastname: Wallesch
authors.forename: Alf
authors.initials: A
authors.lastname: Kozian
authors.forename: Christof
authors.initials: C
authors.lastname: Huth
authors.forename: Michael
authors.initials: M
authors.lastname: Goertler
mesh_terms: D001921:Brain / Q000503:physiopathology*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D016893:Carotid Stenosis / Q000150:complications* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology*