A Model of Femoral Arterial Stenosis to Evaluate Anti-platelet Drugs in Baboons

Abstract number: P0012

Meiring SM, Lamprecht S, Roodt J, Badenhorst PN

A model of femoral arterial stenosis was used to evaluate the antithrombotic efficacy of an anti-platelet drug Reopro^® on platelet-mediated thrombosis in baboons. This model is a modification of the original Folt's model that allows platelet-thrombi to be formed on the injured stenosed artery producing cyclic flow reductions (CFR's). Four baboons were anesthetised with ketamine hydrochloride. An arteriovenous silicon shunt was implanted in the femoral vessels of the baboon. The shunt allows a two-fold higher shear rate and is not thrombogenic. A clot that breaks loose from the injured site, it can easily be removed by flushing the shunt with saline. The flow probe was fitted around the shunt and not around the artery which prevents disturbance of blood flow when changing the stenosis. The mean blood flow was recorded continuously during the experiment. The femoral artery was injured proximal to the shunt by applying 2 occlusions of the artery with the use of a spring-loaded forceps. An easily adjustable clamp was placed in the middle of the injured site to produce an external stenosis of 80%. A gradual decline in blood flow due to platelet adhesion and aggregation was observed. When flow reached zero, blood flow was restored by opening the clamp and mechanically dislodge the platelet-rich thrombus. A clot that breaks loose from the injured site, can easily be removed by flushing the shunt with saline. After an hour of control CFR's, the drug was administered at concentrations of 4, 20, 100 and 250 µg/kg, 30 min apart. Stable CFR's (3–4 min each) were obtained during the control phase. The highest dose of 250 µg/kg abolishes CFR-formation completely and the CFR's did not re-appear when epinephrine was administrated. This model of femoral arterial stenosis is suitable for the evaluation of anti-platelet drugs in baboons.