Effects of abciximab, ticlopidine, and combined abciximab/ticlopidine therapy on platelet and leukocyte function in patients undergoing coronary angioplasty

Background-Abciximab and ticlopidine reduce adverse cardiovascular events a fter percutaneous transluminal coronary angioplasty (PTCA). The goal of the current study was to determine if combined abciximab/ticlopidine therapy i nhibits arterial thrombosis more effectively than either treatment alone. T he effect of each therapy on platelet-leukocyte interactions was also inves tigated. Methods and Results-Whole blood samples from 14 patients undergoing PTCA wh o received abciximab therapy, ticlopidine therapy, or both treatments were evaluated using dynamic experimental systems. Mural thrombus formation unde r arterial shear conditions (1500 s(-1)) was determined in a parallel plate now chamber, Shear-induced platelet aggregation was evaluated using a cone -and-plate viscometer at a shear rate of 3000 s(-1). Of the 3 treatments, c ombined abciximab/ticlopidine therapy produced the most consistent reductio n in shear-induced platelet aggregation and the most prolonged inhibition o f mural thrombosis. Three days after PTCA, abciximab/ticlopidine treatment decreased mural thrombus formation to approximate to 50% of baseline values . Abciximab treatment alone inhibited mural thrombosis for only 1 day after PTCA, whereas ticlopidine treatment alone had no significant effect. Two h ours after PTCA, abciximab therapy significantly decreased the number of ci rculating platelet-neutrophil aggregates but significantly enhanced P-selec tin-mediated leukocyte adhesion on the collagen/von Willebrand factor-plate let surface, Conclusions-Combined therapy with abciximab and ticlopidine has a prolonged inhibitory effect on mural thrombosis formation relative to either treatme nt alone. Further, we demonstrated an unexpected effect of abciximab in enh ancing P-selectin-mediated leukocyte adhesion.