title: Effect of intracoronary gamma-radiation therapy on in-stent restenosis: An intravascular ultrasound analysis from the gamma-1 study.
abstract: BACKGROUND
  The aim of this study was to use serial volumetric intravascular ultrasound to evaluate the effect of gamma-radiation on recurrent in-stent restenosis.
  
  
  RESULTS
  After successful reintervention, patients were randomized to receive either (192)Ir or placebo. Intravascular ultrasound studies with motorized pullback (0.5 mm/s) were performed immediately after irradiation and at 8-month follow-up in 70 patients. Paired volumetric analysis of the stented segment and of 5-mm proximal and distal reference segments was performed; this included measurements of the external elastic membrane, lumen, plaque and media (external elastic membrane minus lumen), stent, and intimal hyperplasia (stent minus lumen). Baseline proximal reference, stent, and distal reference measurements were similar in both groups. The changes in proximal and distal reference measurements of the external elastic membrane, plaque and media, and lumen areas were similar in both groups. However, the decrease in stented segment lumen volume was less in the (192)Ir patients than the placebo patients (-25+/-34 mm(3) versus -48+/-42 mm(3); P:=0.0225), and the increase in the volume of intimal hyperplasia in the stented segment was less in the (192)Ir patients than in the placebo patients (28+/-37 mm(3) versus 50+/-40 mm(3); P:=0.0352). When averaged over the length of the stented segment (32+/-13 mm versus 33+/-14 mm; P:=0.9), the increase in mean area of intimal hyperplasia was 0.8+/-1.0 mm(2) in the (192)Ir group and 1.6+/-1.2 mm(2) in the control group (P:=0.0065). Late stent-vessel wall malapposition was noted in one placebo patient and no (192)Ir patients.
  
  
  CONCLUSIONS
  gamma-Radiation therapy can effectively prevent recurrent in-stent restenosis by inhibiting neointimal formation within the stent. At the stent edge, there were no significant differences between (192)Ir and placebo patients.
authors: Intravascular Ultrasound Imaging Laboratory, Washington Hospital Center, Washington, DC, USA. gsm1@mhg.edu
authors: G S
authors: GS
authors: Mintz
authors: N J
authors: NJ
authors: Weissman
authors: P S
authors: PS
authors: Teirstein
authors: S G
authors: SG
authors: Ellis
authors: R
authors: R
authors: Waksman
authors: R J
authors: RJ
authors: Russo
authors: I
authors: I
authors: Moussa
authors: P
authors: P
authors: Tripuraneni
authors: S
authors: S
authors: Jani
authors: Y
authors: Y
authors: Kobayashi
authors: J A
authors: JA
authors: Giorgianni
authors: C
authors: C
authors: Pappas
authors: R A
authors: RA
authors: Kuntz
authors: J
authors: J
authors: Moses
authors: M B
authors: MB
authors: Leon
mesh_terms: D000704:Analysis of Variance; D003327:Coronary Disease / Q000209:etiology / Q000628:therapy*; D003331:Coronary Vessels / Q000473:pathology / Q000528:radiation effects; D005500:Follow-Up Studies; D005720:Gamma Rays; D006801:Humans; D006965:Hyperplasia / Q000517:prevention & control; D007495:Iridium; D011475:Prosthesis Failure; D015607:Stents
chemical_list: D007495:Iridium