Carotid endarterectomy monitored with transcranial Doppler

Area of Science:

• Neurosurgery
• Vascular Surgery
• Neurology

Background:

• Carotid endarterectomy is a common procedure to prevent stroke.
• Cerebral ischemia can occur during carotid clamping, potentially leading to stroke.
• Monitoring techniques are crucial for patient safety during carotid surgery.

Purpose of the Study:

• To evaluate the utility of intraoperative transcranial Doppler (TCD) monitoring in detecting cerebral ischemia during carotid clamping.
• To assess the impact of carotid shunting on stroke rates based on TCD-identified ischemia severity.
• To compare TCD with electroencephalogram and carotid back pressure for ischemia detection.

Main Methods:

• 238 carotid artery operations, primarily endarterectomies, were monitored using intraoperative TCD.
• Patients were classified into no, mild, or severe ischemia based on middle cerebral artery mean velocity reduction during clamping.
• Stroke rates were compared between patients with and without shunts across different ischemia categories.

Main Results:

• TCD monitoring effectively identified varying degrees of cerebral ischemia.
• Shunting maintained "no ischemia" velocity during bypass.
• Stroke risk was significantly lower without a shunt in the "no ischemia" group (2/175 vs. 2/12).
• Shunting did not alter stroke rates in the "mild ischemia" group (1/20 vs. 0/9).
• Shunting reduced stroke incidence in the "severe ischemia" group (4/9 vs. 0/13).
• Intraoperative electroencephalogram predicted most, but not all, severe ischemia cases.
• TCD proved more helpful than carotid back pressure in assessing ischemia.

Conclusions:

• Intraoperative TCD is a valuable technique for monitoring cerebral ischemia during carotid surgery.
• Carotid shunting is beneficial in reducing stroke rates for patients experiencing severe cerebral ischemia during carotid clamping.