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) was circulated in PVC tubing systems. At fixed intervals over a 10-min time course, aliquots of PRP were drawn, stained with monoclonal antibodies (CD41a, CD42b, CD62p, and CD63), and analyzed by flow cytometry. Within 2 minutes of the onset of circulation, expression of the activation-dependent antigens CD62p and CD63 increased in all tubing systems with stents. This early increase was followed by a progressive rise in fluorescence intensity of these neoantigens over the course of 10 minutes (p < 0.05 vs.. control system without stent). Antigens CD41a and CD42b did not show significant changes in either system. The artificial surfaces and shear forces of stent meshes induce alterations in platelet antigens. Flow cytometry provides a sensitive technique for in vitro testing of the thrombogenicity of coronary stents, and may be useful in further improving stent biocompatibility.