Carotid angioplasty and stenting: will periprocedural transcranial Doppler monitoring be important?

PURPOSE: To explore the value of transcranial Doppler (TCD) ultrasonography in the periprocedural monitoring of patients undergoing angioplasty procedures for stenosis of the internal carotid artery.
METHODS: Thirty-two patients were included in the study between April 1991 and September 1995 (6 females, 26 males; average age 66 years). All patients were interrogated before and after angioplasty by a standard TCD examination protocol. Intraprocedurally, TCD was used continuously to monitor cerebral blood flow and supply evidence of embolic particulates. Nineteen patients were treated by percutaneous transluminal angioplasty (PTA) alone; the other 13 underwent primary stent (PS) implantation.
RESULTS: High-intensity transient signals indicative of emboli appeared to be more frequent in the PTA group than in the PS cohort. Preoperative TCD identified 3 (9%) high-risk patients with incompetent collateral pathways through the circle of Willis. Intraoperatively, TCD detected two postdilation carotid occlusions, a sylvian embolism, and one case of arterial spasm. The preprocedural TCD in a patient with contralateral carotid occlusion showed good collateral circulation, providing reassurance during conversion to endarterectomy when an undeployed stent obstructed blood flow. Postoperatively, TCD confirmed restored intracerebral circulation and identified one hyperperfusion syndrome.
CONCLUSIONS: TCD is a simple, relatively inexpensive examination that can preprocedurally identify carotid stenosis patients at high risk for intraoperative cerebral ischemia in whom PTA might be preferable to surgery. During the procedure, TCD can document the benefits of endovascular treatment and offer early detection of ischemic complications.