title: Cerebral hyperperfusion syndrome after superficial temporal artery-middle cerebral artery bypass for severe intracranial steno-occlusive disease: a case control study.
abstract: BACKGROUND
  Intracranial stenoses carry increased risk for cerebral ischemia. We perform external carotid-internal carotid (EC-IC) artery bypass in our patients with severe stenosis of the intracranial internal carotid (ICA) or middle cerebral artery (MCA) with impaired cerebral vasodilatory reserve (CVR).
  
  
  OBJECTIVE
  To evaluate cerebral hemodynamics and cerebral hyperperfusion syndrome (HPS) in patients who develop focal neurological deficits after EC-IC bypass surgery.
  
  
  METHODS
  Patients with severe intracranial ICA or MCA stenosis and impaired CVR on transcranial Doppler (TCD) derived breath-holding index (BHI) were evaluated with acetazolamide-challenged technetium-99m hexamethylpropyleneamineoxime-single-photon emission computed tomography (SPECT). EC-IC bypass surgery was offered to patients with impaired CVR on SPECT. Close monitoring was performed in patients developing focal neurological deficits within 7 days of surgery.
  
  
  RESULTS
  Of 112 patients with severe intracranial ICA/MCA stenosis, 77 (69%) showed impaired CVR and 46 (41%) underwent EC-IC bypass. Transient neurological deficits within 7 days of surgery developed in 8 (17%). HPS was confirmed by CT perfusion and/or SPECT in 7 cases. A strong correlation was observed between HPS and preoperative TCD-BHI values (0%, 6.3%, and 41% in patients with BHI 0.3-0.69, 0-0.3 and <0, respectively; P = .012). HPS patients showed more than a 50% increase in MCA flow velocity on TCD (compared with preoperative values) on the operated side (63.3% vs 3.3% on control side, P < .001). Meticulous control of blood pressure and hydration led to rapid and complete resolution of neurological deficits in all cases.
  
  
  CONCLUSIONS
  Symptomatic cerebral HPS is common in the early postoperative period after EC-IC bypass surgery. Early diagnosis and appropriate management might prevent the complications of this syndrome.
authors: Division of Neurosurgery, National University Hospital, Singapore.
authors: Kejia
authors: K
authors: Teo
authors: David K S
authors: DK
authors: Choy
authors: Sein
authors: S
authors: Lwin
authors: Chou
authors: C
authors: Ning
authors: Tseng Tsai
authors: TT
authors: Yeo
authors: Liang
authors: L
authors: Shen
authors: Vincent F
authors: VF
authors: Chong
authors: Hock L
authors: HL
authors: Teoh
authors: Raymond C
authors: RC
authors: Seet
authors: Bernard P L
authors: BP
authors: Chan
authors: Arvind K
authors: AK
authors: Sharma
authors: Vijay K
authors: VK
authors: Sharma
mesh_terms: D001921:Brain / Q000098:blood supply*; D002545:Brain Ischemia / Q000453:epidemiology / Q000209:etiology*; D016022:Case-Control Studies; D002539:Cerebral Arterial Diseases / Q000601:surgery; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002561:Cerebrovascular Disorders / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D011183:Postoperative Complications / Q000453:epidemiology*; D013577:Syndrome; D013699:Temporal Arteries; D014656:Vascular Surgical Procedures / Q000009:adverse effects*