Ability of anti-glycoprotein IIb/IIIa agents to dissolve platelet thrombi formed on a collagen surface under blood flow conditions

AbstractObjectivesWe examined the lytic effects of anti-glycoprotein (GP) IIb/IIIa agents on platelet thrombi formed on the collagen surface under blood flow conditions.BackgroundAnti-GP IIb/IIIa agents may influence platelet thrombi already formed.MethodsBlood samples were anticoagulated either by the specific antithrombin Argatroban (100 μM) or by unfractionated heparin (0.1 U/ml). After platelet thrombi were formed on a collagen surface following 6-min perfusion of whole blood obtained from eight adult donors containing fluorescinated platelets at a wall shear rate of 1,500 s−1, additional blood samples from the same donors either containing or not containing anti-GP IIb/IIIa agents (abciximab, eptifibatide, or tirofiban) were perfused on these thrombi. The three-dimensional structures of the platelet thrombi were continuously observed by laser confocal microscopy equipped with a piezo-electric motor control unit and recorded.ResultsThe platelet thrombi started to dissolve after perfusion of blood containing the anti-GP IIb/IIIa agents, whereas their growth resumed after subsequent perfusion of control blood. Only a single layer of platelets having heights of 3 ± 1 μm, 3 ± 2 μm, and 3 ± 1 μm, respectively, could be seen after 6-min perfusion of blood containing abciximab, eptifibatide, and tirofiban, whereas the initial height of the platelet thrombi of 8 ± 2 μm increased to 11 ± 4 μm after subsequent perfusion of control blood (n = 8). The volume of the platelet thrombi, which was 3,352 ± 1,045 μm3before starting the second perfusion, was reduced to 778 ± 102 μm3, 812 ± 122 μm3, and 856 ± 144 μm3after 6-min perfusion of blood containing abciximab, eptifibatide, and tirofiban, respectively.ConclusionsWe have shown in this study that anti-GP IIb/IIIa agents possess the ability to dissolve platelet thrombi