title: Rationale and design of the extracranial Carotid artery Aneurysm Registry (CAR).
abstract: BACKGROUND
  Aneurysms of the extracranial carotid artery (ECAA) are rare. Although most ECAA are identified in asymptomatic patients, serious neurological complications may occur. Current literature on treatment outcome contains mainly case reports and small case series with incomplete data and lack of long-term follow-up. There is clear lack on natural follow-up data, and there is no clear treatment algorithm. An international web-based registry to collect data on patients with ECAA is designed to provide clinical guidance on this scarce pathology.
  
  
  METHODS
  The Carotid Aneurysm Registry (CAR) is open for inclusion of all patients with a fusiform or saccular ECAA. Patients with primary or secondary ECAA can be enrolled in CAR independent of the type of treatment (conservative or invasive). CAR participation does not interfere with the local physician's treatment policy. Follow-up and imaging can also be scheduled according to local clinical practice. The primary endpoint of the CAR in conservative patients is occurrence of symptoms related to the aneurysm at 30 days, one, three, and five years. The primary endpoint in invasively treated patients is freedom from symptoms of the aneurysm at 30 days, one, three, and five years.
  
  
  RESULTS
  Analyses will relate outcome to etiology, imaging characteristics, ECAA growth patterns, and (if applicable) revascularization technique applied. The aim of the registry is to prospectively collect follow-up data on patients with an ECAA, being either treated conservatively or by invasive aneurysm exclusion strategies. The CAR database will be used to address diagnostic and therapeutic research questions.
  
  
  CONCLUSIONS
  Collecting and analyzing the data gained from the registry could be the first step towards development of treatment guidelines and expert consensus for the management of ECAA.
authors: Department of Vascular Surgery, UMCU, Utrecht, The Netherlands.
authors: Janna C
authors: JC
authors: Welleweerd
authors: Julius Center for Health Sciences and Primary Care, UMCU, Utrecht, The Netherlands.
authors: Michiel L
authors: ML
authors: Bots
authors: Department of Neurology and Neurosurgery, UMCU, Utrecht, The Netherlands.
authors: L Jaap
authors: LJ
authors: Kappelle
authors: Department of Neurology and Neurosurgery, UMCU, Utrecht, The Netherlands.
authors: Gabriel J
authors: GJ
authors: Rinkel
authors: Department of Neurology and Neurosurgery, UMCU, Utrecht, The Netherlands.
authors: Ynte M
authors: YM
authors: Ruigrok
authors: Department of Medical Genetics, UMCU, Utrecht, The Netherlands.
authors: Annette F
authors: AF
authors: Baas
authors: Department of Neurology and Neurosurgery, UMCU, Utrecht, The Netherlands.
authors: H Bart
authors: HB
authors: van der Worp
authors: Department of Neurology and Neurosurgery, UMCU, Utrecht, The Netherlands.
authors: Mervyn D
authors: MD
authors: Vergouwen
authors: Department of Anatomy, UMCU, Utrecht, The Netherlands.
authors: Ronald L
authors: RL
authors: Bleys
authors: Department of Radiology, UMCU, Utrecht, The Netherlands.
authors: Jeroen
authors: J
authors: Hendrikse
authors: Department of Radiology, UMCU, Utrecht, The Netherlands.
authors: T Rob
authors: TR
authors: Lo
authors: Department of Vascular Surgery, UMCU, Utrecht, The Netherlands.
authors: Frans L
authors: FL
authors: Moll
authors: Department of Vascular Surgery, UMCU, Utrecht, The Netherlands - G.J.deBorst-2@umcutrecht.nl.
authors: Gert J
authors: GJ
authors: de Borst
mesh_terms: D000783:Aneurysm / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy; D058070:Asymptomatic Diseases; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy; D006801:Humans; D011446:Prospective Studies; D012042:Registries; D012107:Research Design; D013997:Time Factors; D016896:Treatment Outcome