Factors associated with stroke or death after carotid endarterectomy in Northern New England

Comparison of observed (gray bars) and expected (black bars) 30-day stroke/death rate. Risk factors include emergency procedure, preoperative ipsilateral stroke, age >70, lack of antiplatelet agent, contralateral internal carotid artery occlusion, and congestive heart failure.

Comparison of observed (gray bars) and expected (black bars) 30-day stroke/death rate, in asymptomatic patients. Risk factors include age >70 and contralateral internal carotid artery occlusion.

Thirty-day stroke/death rate by (A) annual hospital volume of carotid endarterectomies (CEA; P = .143 across volume categories) and (B) annual surgeon volume (P = .642 across volume categories).