The anti-thrombogenicity of
argatroban and
clopidogrel and the influence of these two agents on coagulation and fibrinolysis were investigated. After the infrarenal abdominal aorta of 21 dogs was replaced with a knitted
Dacron prosthesis of 5 mm in internal diameter, the inner
capsule of the graft was evaluated by angioscopy and angiography immediately and 1 week, 2 weeks and 1 month after surgery. The graft patency rate in group I (untreated group, n = 8), group II (
argatroban group, postoperative infusion of 1 microgram/kg/min for 2 weeks, n = 7) and group III (
clopidogrel group, postoperative
oral administration of 12.5 mg/kg/day for 1 month, n = 6) was respectively 75%, 86% and 100% after 1 week; 75%, 86% and 100% after 2 weeks; and 50%, 71% and 100% after 1 month. The mean maximum
stenosis measured by angioscopy was 31% in group I, 5% in group II and 4% in group III after 1 week; 52%, 23% and 13% after 2 weeks; and 61%, 40% and 9% after 1 month. An increase in
thrombin antithrombin III complex (TAT) due to
thrombus was observed in group I, but this was prevented in the treated groups. These results suggest that
argatroban and
clopidogrel are useful anti-thrombogenic agents for obtaining a thin inner
capsule after graft implantation, especially in small caliber grafts.