A technique to investigate microvascular mural thrombus formation in arteries and veins: II. Effects of aspirin, heparin, r-hirudin, and G-4120.

Abstract

After a standardized trauma to carotid arteries or femoral veins of hamsters, the antithrombotic effects of two antiplatelet agents (aspirin and the glycoprotein IIb/IIIa antagonist G4120) and two anticoagulants (heparin and the direct thrombin inhibitor r-hirudin) were studied in vivo. The thrombus area volume was assessed by image analysis of the transilluminated experimental vessels. Heparin, r-hirudin, and G-4120 demonstrated a dose-dependent complete inhibition of arterial and venous thrombosis. In contrast, the antithrombotic effect of aspirin was only partial in both vessel types. A significant correlation between activated partial thromboplastin time (aPTT) at the end of the experiments and the antithrombotic effect was observed with the anticoagulant agents. However, only r-hirudin inhibited thrombus formation at a therapeutical prolongation of aPTT, while heparin required supratherapeutical amounts to achieve the same inhibition. The data confirm that the inhibition of aspirin, heparin, r-hirudin, and G-4120 on the formation of platelet-rich thrombi is independent of the blood flow rate.