['In large randomized trials, carotid endarterectomy (CEA) for asymptomatic stenosis has shown a net benefit compared with best medical treatment. To justify an increased number of procedures for this indication, the perioperative risk of stroke or death must not exceed that of the trials. The aim of this study was to evaluate the outcome in routine clinical practice in Sweden in a population-based study.', 'The Swedish Vascular Registry (Swedvasc) covers all centers performing CEA. Data on all registered CEAs during 1994 to 2003 were analyzed both for the whole time period and for two 5-year periods to study alterations over time. Four validation procedures of the registry were performed. Medical records were reviewed for both a random sample and a target sample (a total of 12% of the CEAs for asymptomatic stenosis). Swedvasc data were cross-matched with the In-Patient-Registry (used for reimbursement) and the Population-registry (death).', 'A total of 6182 CEAs were registered, 671 being for asymptomatic stenosis. In the validation process, no missed registration of major stroke or death was found. Patients with asymptomatic stenosis had, when the whole time-period was analyzed, a perioperative combined stroke or death rate of 2.1%. Outcome improved over time; the combined stroke or death rate decreased from 3.3% (11/330) from 1994 to 1998 to 0.9% (3/341) from 1999 to 2003 (P = .026). During the second time period, no patient with a perioperative major stroke or death was reported.'] Are outcomes of carotid endarterectomy for asymptomatic stenosis in Sweden improving : Results from a population-based registry?