title: Cerebral blood flow in patients with chronic heart failure before and after heart transplantation.
abstract: OBJECTIVE
  Arterial blood pressure and cardiac output are often reduced in patients with chronic heart failure (CHF). Counterregulatory mechanisms with increased neurohormonal activation and changes in the distribution of cardiac output are assumed to secure vital organ perfusion. However, clinical examination of patients with CHF frequently reveals neurological symptoms with dizziness and memory problems, suggesting altered brain perfusion. In this study we determined whether cerebral blood flow (CBF) is reduced in patients with New York Heart Association (NYHA) functional class III and IV (n=12) compared with healthy control subjects (n=12). Furthermore, we examined whether heart transplantation (n=5) could restore CBF.
  
  
  METHODS
  CBF was estimated by single-photon emission computed tomography and (133)Xe as tracer, and middle cerebral artery velocity was measured by transcranial Doppler ultrasound.
  
  
  RESULTS
  In the CHF patients, CBF was 36+/-1 mL/min per 100 g, corresponding to a 31% reduction compared with the control group (52+/-5 mL/min per 100 g) (P<0.05). After heart transplantation, CBF increased from 35+/-3 mL/min per 100 g before transplantation to 50+/-3 mL/min per 100 g within the first postoperative month (P<0.05).
  
  
  CONCLUSIONS
  We conclude that CBF is substantially, but reversibly, reduced in patients with NYHA class III/IV heart failure. This phenomenon suggests that redistribution of cardiac output inadequately secures brain perfusion in patients with severe CHF.
authors.affiliation: Department of Medicine, Division of Cardiology, Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: N
authors.initials: N
authors.lastname: Gruhn
authors.forename: F S
authors.initials: FS
authors.lastname: Larsen
authors.forename: S
authors.initials: S
authors.lastname: Boesgaard
authors.forename: G M
authors.initials: GM
authors.lastname: Knudsen
authors.forename: S A
authors.initials: SA
authors.lastname: Mortensen
authors.forename: G
authors.initials: G
authors.lastname: Thomsen
authors.forename: J
authors.initials: J
authors.lastname: Aldershvile
mesh_terms: D001783:Blood Flow Velocity; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000032:analysis; D002560:Cerebrovascular Circulation; D002908:Chronic Disease; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging; D014055:Tomography, Emission-Computed; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D002245:Carbon Dioxide