title: The natural history of intimal flaps caused by angioscopy.
abstract: This study tried to determine the natural history of angioscopy-induced arterial intimal flaps as assessed by video angioscopy, light and transmission electron microscopy. Eight mongrel dogs were anesthetized and bilateral femoral and carotid arteries surgically exposed. A 3.0 mm American Edwards angioscope was inserted into each artery and passed vigorously until an intimal flap was visualized by angioscopy. The location of intimal flaps was externally marked with 6-0 polypropylene adventitial sutures. Animals were then recovered and follow-up angioscopy performed at one, two, three, and four week intervals. Following repeat angioscopy, all animals were sacrificed and vessels perfusion-fixed in situ with 2.5% glutaraldehyde in 0.1 M sodium cacodylate. A total of 37 intimal injuries were created (immediate, n = 10; one week, n = 8; two weeks, n = 4; three weeks, n = 8; four weeks, n = 7). No arterial thrombosis occurred following intimal flap formation. Only one of 37 (2.7%) lesions progressed to a hemodynamically significant stenosis. Histology of immediate lesions demonstrated deep intimal fractures extending into the tunica media. Complete healing of intimal flaps was observed by follow-up angioscopy in zero of eight lesions by one week, zero of four lesions by two weeks, one of eight lesions by three weeks, and four of seven lesions by four weeks (p = 0.02). Light and electron microscopy confirmed the angioscopic intimal fractures and regrowth of denuded endothelium.
  
  
  CONCLUSIONS
  follow-up angioscopy and microscopy one month after angioscopy-induced arterial intimal trauma demonstrated a significant trend towards complete endothelial healing.
authors.affiliation: Department of Surgery, University of British Columbia, Vancouver, Canada.
authors.forename: Y N
authors.initials: YN
authors.lastname: Hsiang
authors.forename: M
authors.initials: M
authors.lastname: Fragoso
authors.forename: A
authors.initials: A
authors.lastname: Lundkist
authors.forename: M
authors.initials: M
authors.lastname: Weis
mesh_terms: D000818:Animals; D001158:Arteries / Q000293:injuries* / Q000648:ultrastructure; D004285:Dogs; D019723:Endoscopes; D004724:Endoscopy / Q000009:adverse effects* / Q000379:methods; D004730:Endothelium, Vascular / Q000293:injuries / Q000648:ultrastructure; D005260:Female; D005336:Fiber Optic Technology / Q000295:instrumentation; D005500:Follow-Up Studies; D008297:Male; D008854:Microscopy, Electron; D013997:Time Factors; D014741:Video Recording / Q000295:instrumentation