• M Engelhardt, K Pfadenhauer, J Zentner, S Grimmer, C Wachenfeld-Wahl, P Heidenreich, H Loeprecht, and K D Wölfle.
• Klinik für Gefäss- und Thoraxchirurgie, Zentralklinikum Augsburg, Augsburg. m-engelhardt@web.de
• Zentralbl Chir. 2004 Jun 1; 129 (3): 178-82.

PurposeThe indication for operation in patients with asymptomatic high-grade carotid artery stenosis is still under debate. Since impaired cerebrovascular autoregulation is associated with an increased risk for ischaemic events, assessment of cerebral vascular reactivity might be a valuable selection criterion for surgery. The aim of our study was therefore to evaluate the incidence of impaired autoregulation in asymptomatic patients with acetazolamide-single photon emission computed tomography (ACZ-SPECT) and transcranial CO (2)-dopplersonography (CO (2)-TCD). Furthermore, both methods were compared in regard to results and clinical practicability.MethodsIn 42 patients with high-grade (> 70 %) asymptomatic carotid artery stenosis, cerebral perfusion and vascular reactivity were assessed with resting and ACZ-enhanced SPECT scans. In 31 of these patients the CO (2) reactivity of cerebral perfusion was determined by TCD and expressed as normalized autoregulation reserve (NAR).ResultsCerebral perfusion was decreased in 14.3 %. In ACZ-SPECT 26 % and in CO (2)-TCD 28 % revealed an impaired vascular reactivity. Conformity of both methods was high (kappa = 0.93). TCD was superior in practicability, but only applicable in 81 % due to a missing temporal bone window for insonation.ConclusionIn accordance ACZ-SPECT and CO (2)-TCD could detect impaired vascular reactivity in a quarter of asymptomatic patients. Both TCD and SPECT could be of value for preoperative selection in this group of patients, whereby sonography is recommended for daily diagnostic work-up.

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