Transient Retinal Ischemia During Carotid Endarterectomy Estimated by Intraoperative Visual Evoked Potential Monitoring: Technical Note.

OBJECTIVE

Carotid revascularization surgery is known to carry a risk of postoperative visual deterioration associated with retinal ischemia. We checked intraoperative visual evoked potential (VEP) monitoring in carotid endarterectomy (CEA).

METHODS

Ten consecutive patients who underwent CEA in Shinshu University Hospital under total intravenous anesthesia were checked by intraoperative VEP and electroretinogram (ERG) recording in addition to somatosensory evoked potential monitoring.

RESULTS

Two of 10 patients presented decreased amplitude of VEP and ERG on the ipsilateral affected side by clamping the common carotid artery and persistent attenuation of VEP and ERG during external carotid artery occlusion, using an internal carotid shunt. These findings disappeared immediately after releasing the cervical carotid artery clamping. In the other 8 patients, VEP and ERG did not change throughout the surgery.

CONCLUSIONS

Transient retinal ischemia during even brief carotid artery occlusion in the CEA procedure could be estimated by intraoperative VEP and ERG monitoring.