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(Stroke. 2004;35:1381.)
© 2004 American Heart Association, Inc.

Original Contributions

Effect of Carotid Endarterectomy or Stenting on Impairment of Dynamic Cerebral Autoregulation

M. Reinhard, MD; M. Roth, PhD; T. Müller, PhD; B. Guschlbauer; J. Timmer, PhD; M. Czosnyka, PhD, DSc A. Hetzel, MD

From the Department of Neurology and Clinical Neurophysiology (M. Reinhard, B.G., A.H.) and Center for Data Analysis and Modeling (M. Roth, T.M., J.T.), University of Freiburg, Germany; and Department of Neurophysics (M.C.), Academic Neurosurgery Unit, Addenbrooke’s Hospital, University of Cambridge, UK.

Correspondence to Dr Andreas Hetzel, Department of Neurology and Clinical Neurophysiology, University of Freiburg, Neurocenter, Breisacherstr. 64, D-79106 Freiburg, Germany. E-mail HETZEL{at}nz.ukl.uni-freiburg.de

Background and Purpose— Analysis of dynamic cerebral autoregulation (DCA) from spontaneous blood pressure fluctuations might contribute to prognosis of severe internal carotid artery stenosis, but its response to carotid recanalization has not been investigated so far. This study investigates the effect of carotid endarterectomy or stenting on various DCA parameters.

Methods— In 58 patients with severe unilateral stenosis undergoing carotid endarterectomy (n=41) or stenting (n=17), cerebral blood flow velocity (CBFV, transcranial Doppler) and arterial blood pressure (ABP, Finapres method) were recorded over 10 minutes before and on average 3 days after carotid recanalization. Nineteen patients were additionally examined after 7 months. Correlations between diastolic and mean ABP and CBFV fluctuations were averaged to form the correlation coefficient indices (diastolic [Dx] and mean values [Mx]). Transfer function parameters (low-frequency phase and high-frequency gain between ABP and CBFV oscillations) were calculated over the same 10 minutes. CO₂ reactivity was assessed via inhalation of 7% CO₂.

Results— Before recanalization, all DCA parameters were clearly impaired ipsilaterally compared with contralateral sides. Phase, Dx, and Mx indicated early normalization of DCA after both endarterectomy and stenting. By multiple regression, the degree of DCA improvement was highly significantly related to the extent of impairment before recanalization. No significant change in DCA was found at follow-up. Ipsilateral gain and CO₂ reactivity increased significantly less after endarterectomy than after stenting (P<0.05).

Conclusions— Dynamic cerebral dysautoregulation in patients with severe carotid obstruction is readily and completely remedied by carotid recanalization.

Key Words: internal carotid artery stenosis • carotid endarterectomy • carotid angioplasty, stent-protected • autoregulation, cerebral • transcranial Doppler sonography

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