title: Residual plaque burden, delivered dose, and tissue composition predict 6-month outcome after balloon angioplasty and beta-radiation therapy.
abstract: BACKGROUND
  Inhomogeneity of dose distribution and anatomic aspects of the atherosclerotic plaque may influence the outcome of irradiated lesions after balloon angioplasty (BA). We evaluated the influence of delivered dose and morphological characteristics of coronary stenoses treated with beta-radiation after BA.
  
  
  RESULTS
  Eighteen consecutive patients treated according to the Beta Energy Restenosis Trial 1.5 were included in the study. The site of angioplasty was irradiated with the use of a beta-emitting (90)Sr/(90)Y source. With the side branches used as anatomic landmarks, the irradiated area was identified and volumetric assessment was performed by 3D intracoronary ultrasound imaging after treatment and at 6 months. The type of tissue, the presence of dissection, and the vessel volumes were assessed every 2 mm within the irradiated area. The minimal dose absorbed by 90% of the adventitial volume (D(v90)Adv) was calculated in each 2-mm segment. Diffuse calcified subsegments and those containing side branches were excluded. Two hundred six coronary subsegments were studied. Of those, 55 were defined as soft, 129 as hard, and 22 as normal/intimal thickening. Plaque volume showed less increase in hard segments as compared with soft and normal/intimal thickening segments (P<0.0001). D(v90)Adv was associated with plaque volume at follow-up after a polynomial equation with linear and nonlinear components (r = 0.71; P = 0.0001). The multivariate regression analysis identified the independent predictors of the plaque volume at follow-up: plaque volume after treatment, D(v90)Adv, and type of plaque.
  
  
  CONCLUSIONS
  Residual plaque burden, delivered dose, and tiss composition play a fundamental role in the volumetric outcome at 6-month follow-up after beta-radiation therapy and BA.
authors.affiliation: Thoraxcenter, Heartcenter, Rotterdam, Dijkzigt Academisch Ziekenhuis Rotterdam, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Sabaté
authors.forename: J P
authors.initials: JP
authors.lastname: Marijnissen
authors.forename: S G
authors.initials: SG
authors.lastname: Carlier
authors.forename: I P
authors.initials: IP
authors.lastname: Kay
authors.forename: W J
authors.initials: WJ
authors.lastname: van der Giessen
authors.forename: V L
authors.initials: VL
authors.lastname: Coen
authors.forename: J M
authors.initials: JM
authors.lastname: Ligthart
authors.forename: E
authors.initials: E
authors.lastname: Boersma
authors.forename: M A
authors.initials: MA
authors.lastname: Costa
authors.forename: P C
authors.initials: PC
authors.lastname: Levendag
authors.forename: P W
authors.initials: PW
authors.lastname: Serruys
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D001610:Beta Particles; D001918:Brachytherapy / Q000379:methods*; D003131:Combined Modality Therapy; D003327:Coronary Disease / Q000473:pathology / Q000628:therapy*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D011879:Radiotherapy Dosage; D012044:Regression Analysis; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional