ARTERY STENOSIS,CLINICAL-TRIAL,Aged,Aged,80 and over,Carotid Stenosis,complications,mortality,surgery,Endarterectomy,Carotid,mortality,Female,Humans,Incidence,Kaplan-Meiers Estimate,Male,Middle Aged,Primary Prevention,Stroke,epidemiology,etiology,prevention & control,Time Factors,Treatment Outcome