Risk factors for peri-operative stroke complicating carotid endarterectomy: Selective analysis of a prospective audit of 1000 consecutive operations

Background: The aim of the present study was to investigate the role of potential clinical risk factors in the causation of peri-operative stroke associated with carotid endarterectomy. With the change in carotid endarterectomy practice from the use of a shunt to high-dose thiopental for cerebral protection (a previously undocumented method), it was essential to identify accurately the causes of all perioperative strokes. Methods: A prospective audit was undertaken of 1000 carotid endarterectomies in which the causes and pathology of all peri-operative strokes were documented. The roles of advanced age, female gender, hypertension, previous stroke, contralateral carotid stenosis >70%, and contralateral carotid occlusion as potential causes of peri-operative stroke were defined. Results were statistically analysed using odds ratio and Fisher's exact test. Results: None of the potential risk factors was statistically significant for peri-operative stroke. Female gender was associated with a significant risk of peri-operative stroke due to operative site thrombosis. Complications at the endarterectomy site were the commonest cause of stroke. Conclusions: Prospective audit is a useful tool for identifying causes of peri-operative stroke and indicating the need for modifications to surgical clinical management which might improve outcomes for carotid endarterectomy.