A novel balloon angioplasty catheter impregnated with beta-particle emitting radioisotopes for vascular brachytherapy to prevent restenosis - First in vivo results

Background According to early clinical trials, vascular brachytherapy perfo rmed prior to or shortly after angioplasty is very effective in reducing re stenosis rates. The purpose of this study was to investigate the effects of a novel radioactive catheter that allows simultaneous balloon angioplasty and beta-particle irradiation in the prevention of restenosis. Material and Methods The balloon surface of an angioplasty catheter was imp regnated with the radioisotope P-32. Dosimetry calculations using a Monte C arlo method were performed at a radial distance of 0.2 mm from the balloon surface. Rabbit iliac arteries were dilated and simultaneously irradiated w ith a dose of 20 Gy delivered to the adventitia. Control arteries were only dilated and not irradiated. Neointimal areas, cell numbers and the perimet er of the arteries were measured by histomorphometry after 6 weeks. Results Neointima formation was reduced after balloon dilatation and simult aneous beta-particle irradiation using the P-32 impregnated angioplasty cat heter as compared to balloon dilatation alone with a non-impregnated cathet er (0.09+/-0.06 vs 0.27+/-0.09 mm(2) neointimal area and 168 +/- 45 vs 360 +/- 133 cells/0.05 mm(2) neointima, P<0.001 vs control, respectively). In a ddition, balloon dilatation with the P-32 impregnated angioplasty catheter increased the vessel perimeter as compared to balloon dilatation with a non -impregnated catheter (4.7 +/- 0.2 vs 3.9 +/- 0.3 mm, P<0.001 vs control). Conclusions Simultaneous balloon dilatation and vascular brachytherapy with a novel P-32 impregnated angioplasty catheter markedly reduces restenosis in vivo by preventing neointimal hyperplasia and constrictive vascular remo delling. (C) 2000 The European Society of Cardiology.