title: Thrombosis heralding aneurysmal rupture: an exploration of potential mechanisms in a novel giant swine aneurysm model.
abstract: OBJECTIVE
  The relationship between aneurysm dimensions, flow, thrombosis, and rupture remains poorly understood. We attempted to clarify this relationship by exploring various swine aneurysm models.
  
  
  METHODS
  Bilateral carotid aneurysms were constructed according to 3 protocols in 24 animals: small aneurysms with wide necks (group 1; n = 6 animals); small aneurysms with small necks (group 2; n = 4 animals), and giant aneurysms with large necks (group 3; n = 14 animals). Group 3 included 3 subgroups, related to testing the model in various experimental conditions: The neck was clipped in 3 animals; venous pouches lacked an endothelial lining in 4 animals; and 7 were control animals. Animals were followed until rupture, or for 1-4 weeks. Angiography was performed postoperatively and before euthanasia. We studied lesion pathology, paying attention to thrombosis, recanalization, wall composition, and perianeurysmal hemorrhage.
  
  
  RESULTS
  Groups differed significantly in aneurysm dimensions and aspect ratio (P = .002). Ruptures occurred more frequently in animals with untreated giant aneurysms (7/7) than in animals with small wide-neck (0/6) or small-neck (2/4) aneurysms (P = .002). Ruptures occurred only in animals with thrombosed aneurysms. Lesions lacking an endothelial lining and 5 of 6 clipped venous pouches thrombosed but did not rupture. One giant lesion ruptured despite complete clipping. The wall was deficient in α-actin and was infiltrated with inflammatory cells and erythrocytes in all thrombosed cases, ruptured or not. Ruptures were associated with recanalizing channels in 9 of 10 cases.
  
  
  CONCLUSIONS
  Thrombosis, inflammation, and recanalization may precipitate aneurysmal ruptures in a swine model.
authors.affiliation: Department of Radiology, Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital, Montreal, Quebec, Canada H2L 4M1. jean.raymond@umontreal.ca
authors.forename: J
authors.initials: J
authors.lastname: Raymond
authors.forename: T E
authors.initials: TE
authors.lastname: Darsaut
authors.forename: M
authors.initials: M
authors.lastname: Kotowski
authors.forename: A
authors.initials: A
authors.lastname: Makoyeva
authors.forename: G
authors.initials: G
authors.lastname: Gevry
authors.forename: F
authors.initials: F
authors.lastname: Berthelet
authors.forename: I
authors.initials: I
authors.lastname: Salazkin
mesh_terms: D017542:Aneurysm, Ruptured / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D001706:Biopsy; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology; D002340:Carotid Artery Diseases / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation / Q000502:physiology; D004195:Disease Models, Animal; D002532:Intracranial Aneurysm / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D012720:Severity of Illness Index; D034421:Sus scrofa; D013927:Thrombosis / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D014657:Vasculitis / Q000150:complications / Q000473:pathology / Q000503:physiopathology