title: Efficacy and safety of absorbable metallic stents with adjunct intracoronary beta radiation in porcine coronary arteries.
abstract: BACKGROUND
  Absorbable metallic stents (AMS) utilizing Mg alloy carry advantages over permanent metallic stents because of their potential to eliminate stent thrombosis, chronic inflammation, or artifacts with noninvasive imaging. These stents, however, are associated with a modest degree of late recoil and intimal hyperplasia. The aim of the study was to test whether adjunct vascular brachytherapy (VBT) compared to AMS alone can overcome these limitations.
  
  
  METHODS
  Juvenile domestic pig coronary arteries underwent implantation of either AMS (n = 11) with prior adjunct VBT utilizing Sr/Y-90 beta source seeds, with a dose of 24 Gy at 2 mm from the source, or AMS alone (n = 11). At 28 days following intravascular ultrasound, vessels were harvested and analyzed by histomorphometry.
  
  
  RESULTS
  Intravascular ultrasound analysis indicated that at follow-up, though statistically not significant, lumen and stent areas in the segments deployed with AMS following radiation were larger than those deployed with AMS alone (3.94 +/- 1.38 and 3.53 +/- 1.75 vs. 2.99 +/- 1.05 and 3.58 +/- 1.48). Extrastent plaque and intrastent plaque areas in the same segments were smaller (2.76 +/- 0.82 and 0.24 +/- 0.47 vs. 3.25 +/- 1.94 and 0.58 +/- 0.81). Morphometric data indicate that vessels in the VBT + AMS group showed characteristics of delayed healing and re-endothelialization. Neointimal area was significantly lower in the VBT + AMS group (0.49 +/- 0.34) compared to AMS (1.3 +/- 0.62, P = 0.001). Lumen area of the VBT + AMS was larger when compared with AMS alone (2.49 +/- 0.82 vs. 1.75 +/- 0.51, P = 0.02).
  
  
  CONCLUSIONS
  VBT as an adjunct to AMS further reduces the intimal hyperplasia and improves the lumen area when compared to AMS alone but does not have any impact on late recoil.
authors: Cardiovascular Research Institute, Washington Hospital Center, Washington, DC 20010, USA. ron.waksman@medstar.net
authors: Ron
authors: R
authors: Waksman
authors: Rajbabu
authors: R
authors: Pakala
authors: Teruo
authors: T
authors: Okabe
authors: David
authors: D
authors: Hellinga
authors: Rosanna
authors: R
authors: Chan
authors: Min O
authors: MO
authors: Tio
authors: Eric
authors: E
authors: Wittchow
authors: Sonja
authors: S
authors: Hartwig
authors: Karl-Heinz
authors: KH
authors: Waldmann
authors: Claus
authors: C
authors: Harder
mesh_terms: D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D003324:Coronary Artery Disease / Q000503:physiopathology* / Q000532:radiotherapy; D023903:Coronary Restenosis / Q000532:radiotherapy*; D003331:Coronary Vessels / Q000473:pathology*; D008274:Magnesium; D015607:Stents; D013552:Swine; D018084:Ultrasonography, Interventional
chemical_list: D008274:Magnesium