LOCAL-DELIVERY OF ANTITHROMBOTIC DRUG INHIBITS NEOINTIMAL HYPERPLASIAFOLLOWING ARTERIAL INJURY

The efficacy of local delivery of antithrombotic drugs on neointimal h yperplasia was investigated in 41 rabbits. One side of a rabbit iliac artery was injured by a balloon catheter as a control-injured artery. Another side of the iliac artery was also injured and followed by loca l delivery of the antithrombotic drug (argatroban: 0.05 mg/kg; heparin 25 U/kg; or batroxobin 1 U/kg + heparin 25 U/kg). One hour after the balloon injury, angioscopy demonstrated occlusive or mural thrombus in all the controls, but few in the local drug-delivery arteries. Four w eeks after balloon injury angiographic percent stenosis in the locally ; drug-delivered arteries was 8% +/- 2% in the argatroban group (n = 7 , P < 0.001 vs control side: 67% +/- 33%), 25% +/- 19% in the heparin group (n = 5, P < 0.005 vs control 66% +/- 14%), and 5% +/- 5% in the batroxobin group (n = 7, P < 0.01 vs control 59% +/- 39%). The activat ed partial thromboplastin time and fibrinogen did not change significa ntly. The PDGF-B chain was prominent at the neointimal layer in all th e controls, but less so in the locally drug-delivered arteries. Thus, local delivery of antithrombotic drugs can inhibit neointimal hyperpla sia after balloon injury by reducing thrombus related growth stimulati on.