LOCAL-DELIVERY OF HEPARIN INHIBITS NEOINTIMAL HYPERPLASIA IN INJURED RABBIT ARTERY

The efficacy of local delivery of an antithrombotic drug on neointimal hyperplasia was investigated in 17 rabbits. One rabbit iliac artery w as injured by a balloon catheter as a control injured artery. The othe r iliac artery was also injured and treated by local delivery of 25 U/ kg of heparin. One hour after the balloon injury, angioscopy demonstra ted an occlusive or mural thrombus in all the controls, but few in the locally-treated arteries. Four weeks after balloon injury, the percen t stenosis was 34 +/- 31% in the heparin treated group (n = 7, p < 0.0 05 vs control side 73 +/- 17%). Accumulation of FITC-labeled heparin a t the injured site was confirmed by microscopy. The activated partial thromboplastin time and fibrinogen level did not change significantly. PDGF-B chain was prominent at the neointimal layer in all the control s, whereas it was less in the locally treated arteries. Thus local del ivery of heparin can inhibit neointimal hyperplasia after balloon inju ry by reducing thrombus-related growth stimulation.