Influence of abciximab on the adhesion of platelets on a shielded plasma gradient prepared on polyethylene

INTRODUCTION: Thrombotic effects of biomaterial implants are mediated merely through activation of the platelet glycoprotein IIb-IIIa (GpIIb-IIIa) receptor. Consequently, platelet GpIIb-IIIa receptor inhibitors are successfully used during stent implantation procedures to prevent thrombosis. However, currently a new generation of stents contains surface coating, which changes the surface to more hydrophobic or hydrophilic. This change markedly affects the interaction of platelets and may influence the efficiency of GpIIb-IIIa inhibitors. MATERIALS AND METHODS: To study the influence of the wettability of biomaterials on the effectiveness of abciximab, 5-cm polyethylene gradients with contact angles of 100 degrees to 40 degrees were made by means of glow discharge. Fresh whole blood with or without abciximab was recirculated over this gradient. RESULTS: Inhibition of platelet adhesion by abciximab was maximal, but not complete, on the hydrophobic and moderate hydrophobic part of the gradient, with contact angles of 55 degrees to 90 degrees. Percentage inhibition by abciximab was maximal around 60 degrees. CONCLUSIONS: Intermediate hydrophobicity of currently applied stent materials, such as stainless steel, seems optimal in combination with abciximab. However, on hydrophobic and particularly on hydrophilic materials, abciximab is less effective.