Platelet-Mediated Thrombosis and Drug-Eluting Stents

Stent thrombosis is an example of device-induced, platelet-mediated arterial thrombosis. Rates of stent thrombosis can vary from 10% depending on the patient population, genetic predisposition, device type, pharmacological choices, and duration of antiplatelet pharmacotherapy. The Platelet Colloquium is an annual academic–industry–governmental think-tank meeting devoted to identifying research challenges in platelet biology and clinical applications. The latest meeting was held in Washington, DC, on January 25 to 26, 2011, and this review summarizes the discussions of biocompatible stent design, platelet function assessment, and prevention of thrombosis via short- and long-term P2Y12 platelet receptor antagonism. ### Stent Design and Surface-Mediated Platelet Activation The vascular injury induced by percutaneous coronary intervention (PCI) produces dynamic changes on the surface of human platelets.1 Activated platelets are among the first cells to arrive at the site of injury. Stent thrombosis results from the interaction of several procedural, anatomic, and genetically determined factors.2 Early cellular and inflammatory events are influenced by the properties of the stent or its coating. First-generation drug-eluting stents (DES) used relatively thick struts and durable polymers.3 Research efforts focused on development of nonerodable biocompatible materials that could control the release of antiproliferative medications over several weeks.4 In vitro models showed that these devices appeared to be associated with increased platelet activation and adhesion compared with identical bare metal stents (BMS).5 The continuous presence of a durable polymer and drug has been posited to be partly responsible for delayed arterial healing and enhanced stent thrombogenicity.6 Second-generation DES modified some of these components by reducing strut thickness and polymeric drug load.3 In vitro data suggest that the lower polymeric drug load used in current everolimus-eluting stents may have a more favorable thrombogenic profile than BMS controls.7 Recent data also suggest that these devices might favorably affect inflammation and vascular healing after …