title: The effects of intracoronary brachytherapy on the natural history of postangioplasty dissections.
abstract: OBJECTIVE
  The aim of this study was to determine the natural history of postangioplasty intravascular ultrasound (IVUS)-detected dissections and to assess the influence of intracoronary beta-radiation on dissection resolution.
  
  
  BACKGROUND
  Intracoronary radiotherapy is considered to impair exaggerated vessel healing. Conversely, excessive healing impairment may increase the risk of complications due to unhealed dissection. Alternatively, residual dissection may represent an innocent marker of adequate therapy.
  
  
  METHODS
  Immediate postangioplasty and six-month follow-up IVUS studies of 94 patients in the IVUS substudy of the MultiVitamins and Probucol (MVP) trial and 26 nonstented patients in the Beta Energy Restenosis Trial (BERT) were analyzed for the presence or absence of dissection.
  
  
  RESULTS
  Of the 28 patients with postangioplasty dissections in MVP, only one had evidence of residual dissection at six months (95% confidence interval [CI] for failure rate 0.2%; 20.2%). Conversely, 9 of 16 dissections had healed in BERT (95% CI for failure rate 30.6%; 79.2%) (p < 0.0002). Nevertheless, an index based on dissection arc and length demonstrated improvement in the irradiated patients. Irradiated patients with residual dissections showed significant increase in lumen area at six-months (5.10 +/- 0.98 to 7.11 +/- 2.61 mm2, p < 0.02) not noted when there was resolution of the dissection (6.03 +/- 2.38 to 6.36 +/- 3.33 mm2, p = NS). In both groups the external elastic membrane area was unchanged at follow-up.
  
  
  CONCLUSIONS
  Resolution appears to be the natural history of IVUS-detected dissections in most cases. Significant resolution of dissection occurs following intracoronary beta-radiation as reflected in reduced dissection index at six-months in these patients, although significant impairment of vessel wall healing was noted.
authors.affiliation: Montreal Heart Institute, Quebec, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Meerkin
authors.forename: J C
authors.initials: JC
authors.lastname: Tardif
authors.forename: O F
authors.initials: OF
authors.lastname: Bertrand
authors.forename: J
authors.initials: J
authors.lastname: Vincent
authors.forename: F
authors.initials: F
authors.lastname: Harel
authors.forename: R
authors.initials: R
authors.lastname: Bonan
mesh_terms: D000784:Aortic Dissection / Q000000981:diagnostic imaging / Q000209:etiology / Q000532:radiotherapy*; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects*; D001610:Beta Particles / Q000627:therapeutic use; D001918:Brachytherapy / Q000379:methods*; D003323:Coronary Aneurysm / Q000000981:diagnostic imaging / Q000209:etiology / Q000532:radiotherapy*; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000528:radiation effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional