title: Cerebrovascular reactivity in hypertensive patients: a transcranial Doppler study.
abstract: OBJECTIVE
  We studied the usefulness of transcranial Doppler sonography for assessing changes in vasoreactivity in patients with hypertension and the hemodynamic consequences of hypertension.
  
  
  METHODS
  The study group comprised 25 patients with chronic severe hypertension and 25 age- and sex-matched healthy subjects. Cerebrovascular reserve capacity was assessed by transcranial Doppler recording of the blood flow velocity in both middle cerebral arteries before and 5, 10, 15, and 20 minutes after intravenous injection of 1 g of acetazolamide (Diamox). Blood pressure, blood gases, and other blood parameters were also measured before and after acetazolamide injection. The sizes of the left atrium, left ventricle, and aortic root were measured by echocardiography and correlated with the vasoreactivity after acetazolamide injection.
  
  
  RESULTS
  After acetazolamide injection, no significant changes in blood pressure were observed in either group. The mean blood flow velocity in the middle cerebral arteries of hypertensive patients (60.8 +/- 2.6 cm/sec) was not significantly different from that of controls (58.8 +/- 1.9 cm/sec) before acetazolamide injection. Ten minutes after acetazolamide injection, the percentage change in blood flow velocity was significantly lower in the hypertensive group (36.2 +/- 4.5%) than in the controls (52.6 +/- 3.7%). A significant negative correlation (p < 0.05) between decreased vasoreactivity and increased size of the left atrium and aortic root was observed.
  
  
  CONCLUSIONS
  Vasoreactivity decreases in hypertensive patients without neurologic deficits or computed tomography abnormalities. Enlargement of the left atrium correlates well with the severity of the impairment in vasoreactivity. Transcranial Doppler sonography can be a sensitive tool in the investigation of vascular impairment caused by hypertension and in the follow-up of hypertensive patients.
authors.affiliation: Department of Neurology and Psychiatry, University of Debrecen Medical School, Hungary.
authors.forename: A
authors.initials: A
authors.lastname: Ficzere
authors.forename: A
authors.initials: A
authors.lastname: Valikovics
authors.forename: B
authors.initials: B
authors.lastname: Fülesdi
authors.forename: A
authors.initials: A
authors.lastname: Juhász
authors.forename: I
authors.initials: I
authors.lastname: Czuriga
authors.forename: L
authors.initials: L
authors.lastname: Csiba
mesh_terms: D000086:Acetazolamide / Q000008:administration & dosage; D000328:Adult; D001011:Aorta / Q000000981:diagnostic imaging; D001783:Blood Flow Velocity; D002536:Cerebral Arteries / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002908:Chronic Disease; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D017585:Ultrasonography, Doppler, Transcranial; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
chemical_list: D000086:Acetazolamide