[Assessment of cerebrovascular reserve capacity in patients with carotid artery disease using transcranial Doppler sonography and acetazolamide].
OBJECTIVE
In our study we utilised transcranial Doppler sonography (TCD) and the test with intravenously administered acetazolamide (reversible inhibitor of carbonic anhydrase) which causes vasodilatation of the brain resistance vessels to assess cerebrovascular reserve capacity (CVRC) in patients with symptomatic and asymptomatic carotid stenosis.


METHODS
25 patients (22 male, 3 female; aged 46-82; mean 62 years) with carotid artery disease were examined. They were qualified for the operation because of that.


METHODS
Blood flow wave spectrum in the right and left middle cerebral artery (MCA) was analysed. 2 MHz pulsed-wave transducer was placed over the appropriate temporal acoustic window. We measured mean blood flow velocity (Vmean) in both MCAs. The records were taken: a) at rest, b) 15 minutes after 1.0 g of acetazolamide was administered intravenously. Cerebrovascular reserve (CVRC) was calculated as the maximal percentage increase in the appropriate MCA after the administration of acetazolamide in comparison with its value at rest. The values of CVRC were analysed statistically.


RESULTS
15 minutes after acetazolamide was injected CVRC was 44 +/- 15% (mean +/- SD) (range 0-74) in asymptomatic hemispheres. In 30 patients (97%) CVRC was 46 +/- 12% (23-74) and in 1 patient (3%) 0% (case nr 7). In the group of symptomatic hemispheres CVRC was 12 +/- 15% (-16-36) after acetazolamide administration. In 12 patients (63%) from this group CVRC was positive: 20 +/- 11% (3-33), in 4 patients (21%) CVRC was 0% (cases nr 8, 9, 22, 23) and in other 3 patients (16%) CVRC was negative: -7 +/- 8 (-16(-)-3) (cases nr 4, 12, 19).


CONCLUSIONS
1. The group of patients with symptomatic hemispheres have statistically lower CVRC in comparison with the group of asymptomatic hemispheres. 2. There was no statistical difference between the mean values of CVRC in patients with bilateral, severe carotid stenosis and the ones with unilateral changes. 3. We believe that such a test performed by means of TCD and intravenously injected acetazolamide can indicate a subgroup of patients with carotid stenosis for whom carotid endarterectomy is necessary at the earliest time because of possible early neurological complications appearance which are related to the lack or serious impairment of CVRC.
Staszkiewicz
W
W
Kliniki Chirurgii Naczyniowej Centrum Medycznego Kształcenia Podyplomowego w Warszawie.
Antepowicz
W
W
Gabrusiewicz
A
A
Gawlikowska
D
D
D000086:Acetazolamide; D000368:Aged; D000369:Aged, 80 and over; D002257:Carbonic Anhydrase Inhibitors; D016893:Carotid Stenosis / Q000175:diagnosis*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods
D002257:Carbonic Anhydrase Inhibitors; D000086:Acetazolamide