Local Delivery of Antithrombotic Drug Inhibits Neointimal Hyperplasia Following Arterial Injury

The efficacy of local delivery of antithrombotic drugs on neointimal hyperplasia 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 local 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 weeks 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 activated partial thromboplastin time and fibrinogen did not change significantly. The PDGF‐B chain was prominent at the neointimal layer in all the controls, but less so in the locally drug‐delivered arteries. Thus, local delivery of antithrombotic drugs can inhibit neointimal hyperplasia after balloon injury by reducing thrombus related growth stimulation.