Does carotid endarterectomy modify cerebral vasomotor reactivity?

The effects of carotid endarterectomy (CEA) on cerebral hemodynamics in certain groups of patients with severe carotid stenosis still remain unclear. Cerebral vasomotor reactivity (CVR) is an important indicator of intracranial blood supply and cerebral autoregulation. Symptomatic and asymptomatic patients with severe carotid stenosis and impaired CVR were evaluated before and after CEA. Transcranial Doppler ultrasonography (TCD) and the Diamox test (i.v. administration of 1.0 g acetazolamide) before and 3 months after CEA were performed in 42 patients (21 symptomatic, 21 asymptomatic) with severe (70-99%) carotid stenosis. CVR was assessed as the difference between peak blood flow velocities in the middle cerebral artery ipsilateral to the carotid stenosis before and after acetazolamide injection and as percent increase of blood flow velocity after acetazolamide (ANOVA). Three months after CEA there was statistically significant improvement of CVR in asymptomatic compared with symptomatic patients (p < 0.05, ANOVA). CEA improves CVR mostly in asymptomatic patients. TCD combined with the Diamox test appears to be a useful tool in assessing cerebral hemodynamics prior to carotid surgery, and might be an additional criterion for selecting asymptomatic patients for CEA.