Adjunctive anti-thrombotic therapy for PCI of AMI may be improved by incorporation of a novel anti-platelet therapeutic principle, von Willebrand Factor antagonism. ARC1779 is a therapeutic oligonucleotide ("aptamer") which blocks the binding of the A1 domain of vWF to the platelet GPIb receptor, and thereby modulates platelet adhesion, activation, and aggregation under the high shear conditions of coronary arterial stenosis and plaque rupture. This study is intended to provide dose-ranging and clinical proof of concept for ARC1779 in a primary PCI population.