There is no effect on remodeling of vascular wall 4 weeks after local delivery of antithrombin in a porcine model of coronary overstretching

Background Antithrombin III is an effective endogenous inhibitor of thrombi n with antiproliferative and anti-inflammatory capabilities. Systematic adm inistration of direct thrombin inhibitors as well as of antithrombin has pr oven effective at reducing formation of neointima after injury to vessel wa ll in various animal models. Local delivery of antithrombin attenuates depo sition of platelets after balloon injury to porcine coronary vessels. Objective To test our hypothesis that local delivery of antithrombin affect s remodeling of vessel wall after balloon injury to the left anterior desce nding artery (LAD) in pigs. Methods With a balloon:vessel diameter ratio of 1.5 deep vessel-wall injury was performed with conventional balloon angioplasty in the LAD in 16 pigs. After balloon injury the pigs were administered locally two doses of 2.5 m l antithrombin (250 U) or, as a control, two doses of 2.5 ml albumin (10 mg ). All pigs were administered 200 U/kg bodyweight heparin before catheteriz ation. The animals were then kept in stalls and fed normal grain. After app roximately 4 weeks the animals were killed and lesions were assessed by com puter-assisted image analysis. The areas of each vessel-wall layer and the percentage area stenosis were calculated. As a measure of injury, the lengt h of rupture of the lamina elastica interna was measured. Results The injury was found to be equally profound in pigs of these groups . There was no significant difference between the groups concerning the are as of vessel-wall layers. The percentage area stenosis was similar for pigs in these two groups (36.5 +/- 14.9% for pigs in the antithrombin group ver sus 35.4 +/- 16.2% for pigs in the control group, NS). Conclusions Local delivery of 250 U antithrombin to the LAD in pigs did not affect remodeling of the vessel wall 4 weeks after balloon injury. Coron A rtery Dis 12:31-36 (C) 2001 Lippincott Williams & Wilkins.