FLOW CYTOMETRIC ANALYSIS OF CORONARY STENT-INDUCED ALTERATIONS OF PLATELET ANTIGENS IN AN IN-VITRO MODEL

One of the limitations of coronary stenting is the subacute thrombotic occlusion. In an in vitro model, we examined the effects of tantalum wire stents (n=12) on platelet antigens. Platelet-rich plasma (PRP) wa s circulated in PVC tubing systems. At fixed intervals over a 10-min t ime course, aliquots of PRP were drawn, stained with monoclonal antibo dies (CD41a, CD42b, CD62p, and CD63), and analyzed by flow cytometry. Within 2 minutes of the onset of circulation, expression of the activa tion-dependent antigens CD62p and CD63 increased in all tubing systems with stents. This early increase was followed by a progressive rise i n fluorescence intensity of these neoantigens over the course of 10 mi nutes (p < 0.05 vs.. control system without stent). Antigens CD41a and CD42b did not show significant changes in either system. The artifici al surfaces and shear forces of stent meshes induce alterations in pla telet antigens. Flow cytometry provides a sensitive technique for in v itro testing of the thrombogenicity of coronary stents, and may be use ful in further improving stent biocompatibility.