title: The impact of lesion length and reference vessel diameter on angiographic restenosis and target vessel revascularization in treating in-stent restenosis with radiation.
abstract: OBJECTIVE
  The study assessed the influence of lesion length and reference vessel diameter (RVD) on recurrent restenosis after gamma intracoronary radiation therapy (ICRT) for in-stent restenosis (IRS).
  
  
  BACKGROUND
  Intracoronary radiation therapy reduces angiographic and clinical restenosis in patients with ISR. The impact of ICRT on challenging subgroups, such as long lesions and small vessels, has not been established.
  
  
  METHODS
  Six-month quantitative coronary angiography and clinical follow-up were conducted to evaluate the influence of lesion length and RVD in patients with ISR treated with ICRT who were enrolled in gamma radiation trials. Angiographic binary restenosis (>50% diameter stenosis) and clinical events were assessed in 311 patients treated with gamma ICRT and 105 patients who received placebo.
  
  
  RESULTS
  Baseline demographic, angiographic and procedural details were similar in the two treatment groups. The ICRT group had reduced binary restenosis in vessels of all sizes (30% vs. 66%, p < 0.001), with the most benefit seen in small vessels. A trend toward reduced restenosis with ICRT was found across all lesion lengths. At six months, major adverse cardiac events (MACE) were reduced in the ICRT group compared to placebo (34% vs. 71%, p < 0.0001), driven by reduced target vessel revascularization (27% vs. 71%, p < 0.0001). The independent predictors of angiographic restenosis include ICRT (OR [odds ratio] 0.16; CI [confidence interval] 0.10 to 0.28, p < 0.001), lesion length (OR 1.03; CI 1.01 to 1.05, p = 0.004) and RVD (OR 0.40; CI 0.23 to 0.67, p < 0.001).
  
  
  CONCLUSIONS
  Intracoronary radiation therapy, compared to placebo, results in a significant reduction of angiographic restenosis across all vessel sizes, with a trend toward reduction of angiographic restenosis across all lesion lengths; this effect is seen predominantly in small vessels and diffuse lesions.
authors.affiliation: Cardiovascular Research Institute, Washington Hospital Center, Washington, D.C., USA.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Ajani
authors.forename: Ron
authors.initials: R
authors.lastname: Waksman
authors.forename: Dong-Hun
authors.initials: DH
authors.lastname: Cha
authors.forename: Luis
authors.initials: L
authors.lastname: Gruberg
authors.forename: Lowell F
authors.initials: LF
authors.lastname: Satler
authors.forename: Augusto D
authors.initials: AD
authors.lastname: Pichard
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Kent
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000000981:diagnostic imaging / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D003331:Coronary Vessels / Q000528:radiation effects* / Q000601:surgery*; D004219:District of Columbia; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization; D011237:Predictive Value of Tests; D012016:Reference Values; D015607:Stents; D016019:Survival Analysis; D016896:Treatment Outcome