title: Comparative efficacy of gamma-irradiation for treatment of in-stent restenosis in saphenous vein graft versus native coronary artery in-stent restenosis: An intravascular ultrasound study.
abstract: BACKGROUND
  We used serial volumetric (post-irradiation and follow-up) intravascular ultrasound (IVUS) to compare the effectiveness of gamma-irradiation ((192)Ir) in saphenous vein graft (SVG) versus native coronary artery in-stent restenosis (ISR).
  
  
  RESULTS
  The study population consisted of 47 patients with native coronary artery ISR from WRIST (Washington Radiation for In-Stent Restenosis Trial) and 31 patients with SVG ISR (12 from the WRIST and 19 from SVGWRIST). After irradiation and at 6-month follow-up, stent, lumen, and intimal hyperplasia (IH, stent minus lumen) areas were measured every 1 mm. ISR length was similar in the 2 groups (29+/-12 versus 29+/-14 mm, P=0.9). Post-intervention measurements of stent (280+/-154 versus 324+/-270 mm(3), P=0.4), lumen (184+/-91 versus 214+/-172 mm(3), P=0.3), and IH (96+/-77 versus 109+/-119 mm(3), P=0.5) volumes were similar in the 2 groups. The post-intervention minimum lumen cross sectional areas tended to be smaller in native artery ISR lesions (4.7+/-1.7 versus 5.4+/-1.6 mm(2), P=0.11). During follow-up, there was a slight increase in IH volume (9+/-38 mm(3)) in native artery ISR lesions and a slight decrease in IH volume in SVG ISR lesions (-9+/-32 mm(3), P=0.0463). There was also a slight decrease in minimum lumen area in the native artery ISR lesions versus a slight increase in minimum lumen area in the SVG ISR lesions (-0.8+/-1.7 versus 0.2+/-1.1, P=0.0087). As a result, the follow-up minimum lumen area in native artery lesions was smaller than in SVG ISR lesions (4.1+/-2.1 mm(2) versus 5.6+/-2.2 mm(2), P=0.0067).
  
  
  CONCLUSIONS
  gamma-Irradiation with (192)Ir brachytherapy appears to be as effective in SVGs as it is in native artery ISR lesions.
authors.affiliation: Intravascular Ultrasound Imaging and Cardiac Catheterization Laboratories, Cardiovascular Research Institute, Washington Hospital Center, Washington, DC, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Castagna
authors.forename: G S
authors.initials: GS
authors.lastname: Mintz
authors.forename: R
authors.initials: R
authors.lastname: Waksman
authors.forename: J M
authors.initials: JM
authors.lastname: Ahmed
authors.forename: A
authors.initials: A
authors.lastname: Maehara
authors.forename: A E
authors.initials: AE
authors.lastname: Ajani
authors.forename: A B
authors.initials: AB
authors.lastname: Bui
authors.forename: L F
authors.initials: LF
authors.lastname: Satler
authors.forename: W O
authors.initials: WO
authors.lastname: Suddath
authors.forename: K M
authors.initials: KM
authors.lastname: Kent
authors.forename: A D
authors.initials: AD
authors.lastname: Pichard
authors.forename: N J
authors.initials: NJ
authors.lastname: Weissman
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000628:therapy; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects*; D005260:Female; D005500:Follow-Up Studies; D005720:Gamma Rays / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D012501:Saphenous Vein / Q000637:transplantation*; D015607:Stents; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional