Effects of 2 different antiplatelet regimens with abciximab or tirofiban on platelet function in patients undergoing coronary stenting.

BACKGROUND

We sought to compare the antiplatelet effects of the glycoprotein IIb-IIIa receptor blockers abciximab or tirofiban, combined with an adjuvant therapy with clopidogrel and aspirin.

STUDY DESIGN AND METHODS

Twenty patients undergoing coronary stenting were randomly assigned to receive either abciximab or tirofiban combined with aspirin and clopidogrel. Serial blood samples were taken to assess platelet aggregation, P-selectin expression, thrombin generation, and platelet-induced endothelial cell expression of MCP-1, uPAR, and ICAM-1. Results and conclusions The therapy with aspirin plus clopidogrel attenuated agonist-induced platelet aggregation and P-selectin surface exposure (P <.05 vs aspirin monotherapy). Both tirofiban and abciximab further reduced agonist-induced platelet aggregation (P <.05), and decreased thrombin generation but had no effect on platelet alpha-granule release. None of the antithrombotic strategies significantly affected platelet-induced endothelial cell activation. Since platelet adhesion/degranulation initiates an inflammatory/mitogenic response in the vascular wall, future therapeutic strategies will have to be aimed at the inhibition of platelet release reactions.