title: Vascular morphometric changes after radioactive stent implantation: a dose-response analysis.
abstract: OBJECTIVE
  The goal of this study was to evaluate the dose-dependency of morphometric changes in the coronary arterial wall after radioactive stenting.
  
  
  BACKGROUND
  Radioactive stents have been found to reduce intrastent intimal hyperplasia (IIH) but lead to a characteristic type of restenosis occurring predominantly at the stent edges.
  
  
  METHODS
  Fifteen patients underwent intravascular ultrasound (IVUS) examination after implantation of a P-32 radioactive stent and at the six-month follow-up. The post-stent IVUS measurements on seven predefined locations of each lesion were subjected to a computer algorithm for the development of dose-volume histograms (DVH). Thus, we derived the radiation doses delivered to at least 10% and 90% of the adventitia (DV10, DV90). The IIH and vascular remodeling at follow-up were correlated with the doses in each segment.
  
  
  RESULTS
  The IIH was most pronounced at the stent edges and lowest in the stent-body, whereas we detected a significant expansive remodeling within the stent body. The delivered doses correlated with a decreased IIH (r = 0.52, p < 0.001 for DV10 and r = 0.62, p < 0.001 for DV90) and with expansive remodeling (r = 0.48, p = 0.009 for DV10 and r = 0.50, p = 0.006 for DV90). A DV10 >90 Gy or a DV90 >15 Gy reduced IIH and induced expansive remodeling. Plaque growth was not reduced by radioactive stents.
  
  
  CONCLUSIONS
  The DVH analysis reveals a dose-dependent increase of external elastic lamina area behind radioactive stents, whereas plaque growth is not reduced but inverted into an outward direction from the stent. A DV10 >90 Gy or a DV90 >15 Gy results in a beneficial long-term outcome after radioactive stenting.
authors.affiliation: Division of Cardiology, Department of Internal Medicine II, University of Vienna, Vienna, Austria. paul.wexberg@akh-wien.ac.at
authors.forename: Paul
authors.initials: P
authors.lastname: Wexberg
authors.forename: Christian
authors.initials: C
authors.lastname: Kirisits
authors.forename: Mariann
authors.initials: M
authors.lastname: Gyöngyösi
authors.forename: Michael
authors.initials: M
authors.lastname: Gottsauner-Wolf
authors.forename: Meinhard
authors.initials: M
authors.lastname: Ploner
authors.forename: Boris
authors.initials: B
authors.lastname: Pokrajac
authors.forename: Richard
authors.initials: R
authors.lastname: Pötter
authors.forename: Dietmar
authors.initials: D
authors.lastname: Glogar
mesh_terms: D001158:Arteries / Q000000981:diagnostic imaging / Q000528:radiation effects / Q000601:surgery; D019917:Blood Vessel Prosthesis Implantation / Q000295:instrumentation; D023903:Coronary Restenosis / Q000000981:diagnostic imaging / Q000209:etiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000528:radiation effects / Q000601:surgery; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006965:Hyperplasia / Q000209:etiology / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D011859:Radiography; D015607:Stents; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional