title: Experimental model of dissecting aneurysms.
abstract: OBJECTIVE
  The pathogenesis and optimal treatment for arterial dissection are still unclear. We devised an experimental model of arterial dissection and observed the morphologic changes with angiography.
  
  
  METHODS
  Sixty-four experimental dissections were created in the common carotid arteries of 34 mongrel dogs. After a small incision was made in the arterial adventitia, it was dissected from the media. Elliptical defects (2, 4, 6, and 8 mm in groups I-A, I-B, I-C, and I-D, respectively; n = 47) or longitudinal incisions (4, 6, and 8 mm in groups II-A, II-B, and II-C, respectively; n = 17) were made in the intima distal to the adventitial incision to serve as an entry zone for dissection.
  
  
  RESULTS
  Immediately after the lesions were created, the influx of blood into the dissected cavity produced massive subadventitial hematomas, resulting in stenotic changes in all of the arteries, including seven with occlusion. Follow-up (1-week) angiograms demonstrated complete healing, with normal arterial calibers in 11 (79%) of 14 I-A lesions and aneurysm formation in nine (69%) of 13 I-B lesions. All 10 I-D lesions had complete arterial occlusion. Persistent stenosis was observed in all 10 I-C lesions; six of these developed aneurysms. Pathologic examination of the freshly dissected cavities revealed a clot-filled cleft between the media and adventitia. Mature aneurysms, evaluated 3 mo later, had endothelialization within the aneurysmal dome.
  
  
  CONCLUSIONS
  Morphologic changes after arterial dissection are closely related to the size of the intimal entry zone, which may determine whether a dissecting aneurysm forms.
authors.affiliation: Department of Neurosurgery, Nagoya University Graduate School of Medicine, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Okamoto
authors.forename: Shigeru
authors.initials: S
authors.lastname: Miyachi
authors.forename: Makoto
authors.initials: M
authors.lastname: Negoro
authors.forename: Goro
authors.initials: G
authors.lastname: Otsuka
authors.forename: Osamu
authors.initials: O
authors.lastname: Suzuki
authors.forename: Hiroomi
authors.initials: H
authors.lastname: Keino
authors.forename: Jun
authors.initials: J
authors.lastname: Yoshida
mesh_terms: D000784:Aortic Dissection / Q000000981:diagnostic imaging* / Q000473:pathology; D000818:Animals; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000473:pathology; D003251:Constriction, Pathologic; D004285:Dogs; D011859:Radiography