Risk factors for a decrease in somatosensory evoked potential amplitude during carotid endarterectomy with routine shunting.

The median age was 71 years, 82% were male, and 27% had symptomatic carotid disease.

Independent risk factors included symptomatic disease (p = 0.017), severe contralateral carotid stenosis (≥70% or occlusion, p = 0.02), and hypoplasia of either A1 segment (p < 0.001).

In contrast, beta-blocker use was associated with a reduced risk of somatosensory evoked potentials amplitude decreases (p = 0.04).

The incidence of significant decrease in somatosensory evoked potentials amplitude increased with the severity of contralateral stenosis and varied by A1 segment morphology.