title: Vascular brachytherapy using a beta emitter source in diabetic patients with in-stent restenosis: angiographic and clinical outcomes.
abstract: OBJECTIVE
  The management of diabetic patients with restenosis after percutaneous coronary intervention remains a significant challenge. Diabetic patients remain at significant risk of restenosis despite stent implantation. This retrospective analysis was performed to determine the extent to which vascular brachytherapy improves late clinical and angiographic outcomes in diabetic patients compared to conventional therapy and compared to patients' nondiabetic counterparts.
  
  
  METHODS
  Pooled data from two studies (START [Stents and Radiation Trial] and START-40 trials) of patients (204 diabetic, 477 nondiabetic) receiving vascular brachytherapy (VBT) with a (90)Sr/(90)Y source after conventional percutaneous coronary intervention for in-stent restenosis comprise the study population. The radiation delivery system used in both studies was the Beta-Cath system. The prescribed dose at 2 mm from the centerline of the source axis was 18.4 Gy or 23 Gy, depending on vessel diameter. The reference vessel diameter, minimal lumen diameter, and percent diameter stenosis were measured before the intervention, at the conclusion of the procedure, and at the 8-month follow-up examination. The Breslow-Day test was used to formally assess the similarity of treatment effect between diabetic and nondiabetic patients.
  
  
  RESULTS
  Target lesion and target vessel revascularization rates and angiographic restenosis rates in diabetic and nondiabetic patients treated with beta radiation or placebo were analyzed. Diabetic patients were more likely to have longer and more complex coronary lesions. In-hospital outcomes in diabetic and nondiabetic patients were similar, irrespective of treatment status. At 8 months, patients treated with beta radiation exhibited less target lesion revascularization (diabetic: 10.9% vs. 22.7%, p = 0.02; nondiabetic: 12.8% vs. 22.3%, p = 0.007) and less target vessel revascularization (diabetic: 14.7% vs. 25.3%, p = 0.06; nondiabetic: 16.6% vs. 23.6%, p = 0.06) compared to placebo. In-stent binary angiographic restenosis was lower in irradiated patients (diabetic: 19.4% vs. 37.3% for placebo, p = 0.01; nondiabetic: 12.9% vs. 43% for placebo, p < 0.001). However, restenosis beyond the stent site reduced the impact of VBT, regardless of diabetic status. The magnitude of the treatment effect for target lesion and target vessel revascularization rates was similar between diabetic and nondiabetic patients.
  
  
  CONCLUSIONS
  Previously published institutional experiences have suggested that diabetic patients benefit from the use of VBT in the management of in-stent restenosis. This analysis now provides direct evidence to support the role of beta radiation VBT in this patient population. Diabetic patients undergoing this therapy are just as likely to benefit from it as their nondiabetic counterparts.
authors.affiliation: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore 21201, USA. nsunthar@umaryland.edu
authors.forename: Mohan
authors.initials: M
authors.lastname: Suntharalingam
authors.forename: Warren K
authors.initials: WK
authors.lastname: Laskey
authors.forename: Wiwun
authors.initials: W
authors.lastname: Tantibhedhyangkul
authors.forename: Alexandra
authors.initials: A
authors.lastname: Lansky
authors.forename: Paul
authors.initials: P
authors.lastname: Teirstein
authors.forename: Theodore
authors.initials: T
authors.lastname: Bass
authors.forename: Sigmund
authors.initials: S
authors.lastname: Silber
authors.forename: Barry
authors.initials: B
authors.lastname: Rutherford
authors.forename: Charles
authors.initials: C
authors.lastname: Wilmer
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Popma
authors.forename: Richard
authors.initials: R
authors.lastname: Kuntz
authors.forename: Raoul
authors.initials: R
authors.lastname: Bonan
mesh_terms: D001610:Beta Particles / Q000627:therapeutic use; D001918:Brachytherapy / Q000379:methods*; D017023:Coronary Angiography; D023903:Coronary Restenosis / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D003925:Diabetic Angiopathies / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D015607:Stents; D013326:Strontium Radioisotopes / Q000627:therapeutic use; D015021:Yttrium Radioisotopes / Q000627:therapeutic use
chemical_list: D013326:Strontium Radioisotopes; D015021:Yttrium Radioisotopes