A preparation to study simultaneous arterial and venous thrombus formationin rabbits

Injury to an artery induces formation of a platelet-rich thrombus, while st asis or trauma to a vein induces a fibrin-rich thrombus. We have implemente d preparations for evolving both platelet-rich and fibrin-rich thrombi simu ltaneously in rabbits for use to define the efficacy of novel antithromboti c agents. For platelet-rich thrombosis, a carotid artery and contralateral jugular vein were dissected and an arteriovenous shunt inserted distally to prevent cerebral infarction during thrombus formation. The shunted artery was then instrumented with a proximal Doppler probe for measuring flow velo city and a distal transluminal needle electrode. Electrical injury to the a rtery was induced by application of 250 muA of anodal current to the indwel ling needle electrode. Thrombotic occlusion was consistently observed withi n 60 min, permitting measurements of the effects on the incidence and time of occlusion of antithrombotic agents administered over 2 h. For fibrin-ric h thrombosis, an external jugular vein was dissected, including the distal bifurcation. One of the branches was catheterized and a copper wire with co tton threads attached was advanced through the catheter into the superior v ena cava, allowing exposure of the threads to flowing blood. A 25- to 30-mg thrombus was formed within 2 h, permitting reliable measurements of effect s on thrombus weight of antithrombotic agents administered during this inte rval. Implementing both arterial and venous thrombosis simultaneously did n ot change measurements compared with either method alone. This approach may facilitate recognition of differences in efficacy of selected agents again st thrombi of diverse composition.