K. Kozuma et al., Relationship between tensile stress and plaque growth after balloon angioplasty treated with and without intracoronary beta-brachytherapy, EUR HEART J, 21(24), 2000, pp. 2063-2070
Aims We investigated the influence of tensile stress on plaque growth after
balloon angioplasty with and without beta-radiation therapy.
Methods and Results Thirty-one consecutive patients successfully treated wi
th balloon angioplasty were analysed qualitatively and quantitatively by me
ans of an EGG-gated three-dimensional intravascular ultrasound post-procedu
re and at follow-up. Eighteen patients were irradiated with catheter-based
beta-radiation (Sr-90/Y-90 source) and 13 were not (control). Studied segme
nts were divided into 2 mm subsegments. Thus 184 irradiated and 111 non-irr
adiated subsegments were included. Tensile stress was calculated according
to Laplace's law. The radiation dose was calculated by means of dose-volume
histograms. Plaque growth was positively correlated to tensile stress in b
oth the radiation and control groups (r=0.374, P=0.0001 and r=0.305, P=0.00
1). Low-dose subsegments (<6 Gy) had a significant correlation (r=0.410, P=
0.0001) whereas no correlation was observed in the effective-dose subsegmen
ts (<greater than or equal to>6 Gy). Multivariate analysis identified tensi
le stress as the only independent predictor of plaque increase in non-irrad
iated subsegments, whereas actual dose and plaque morphology were stronger
predictors in irradiated subsegments.
Conclusion The results of this study suggest that plaque growth is related
to tensile stress after balloon angioplasty. Intracoronary brachytherapy ma
y alter the biophysical process on plaque growth when the prescribed dose i
s effectively delivered. (C) 2000 The European Society of Cardiology.