Variation in clinical practice in carotid surgery in nine countries 2005-2010. Lessons from VASCUNET and recommendations for the future of national clinical audit.

Objectives The aim of the study was to analyse variation in carotid surgical practice, results and effectiveness in nine countries. Patients and Methods A total of 48,185 carotid endarterectomies (CEAs) and 4602 carotid artery stenting (CAS) procedures were included in the comparison. A theoretical effectiveness of CEA provision for each country was estimated. Results 92.6% of the CEAs were performed according to the inclusion criteria based on the current European recommendations and had a theoretical benefit for the patient. The indication for surgery was symptomatic stenosis in 60.1% and this proportion varied between 31.4% in Italy and 100% in Denmark. The overall combined stroke and death rate in symptomatic patients was 2.3%. This varied between rates of 0.9% in Italy and 3.8% in Norway. The overall combined stroke and death rate in asymptomatic patients was 0.9%. It was lowest in Italy at 0.5%, and highest in Sweden at 2.7%. We estimated that the stroke prevention rate per 1000 CEAs varied from 72.9 in Italy to 130.8 in Denmark. Conclusions There is significant variation in clinical practice across the participating countries. The theoretical stroke prevention potential of CEA seems to vary between participating countries due to differences in the inclusion criteria.