The efficiency of carotid surgery on an asymptomatic carotid artery stenosis and its superiority to conservative treatment was clearly demonstrated in the ACAS study. The stroke risk over a five year follow-up period could be reduced by 55 % and the combined stroke and mortality rate was shown to be a mere 2. 3 %. The efficacy of surgical treatment in also reducing stroke rates in the case of a symptomatic carotid stenosis was proven in the NASCET and ECTS prospective randomized studies. Of extreme importance in these procedures is, however, precise quality control and quality assessment....