Fluorescence spectroscopic analysis of circulating platelet activation during coronary angioplasty

Background and Objective: Platelet activation during percutaneous translumi nal coronary angioplasty (PTCA) initiates thrombus formation and plaque reg rowth at sites of arterial injury, limiting procedure efficacy. We have dev eloped a simple assay for circulating platelet activation based on fluoresc ence analysis of membrane fluidity and intracellular calcium concentration and light scattering analysis of platelet aggregation. Study Design/Materials and Methods: Platelet activation state was measured in 45 patients undergoing angioplasty, before and after treatment with plat elet inhibitors. Results: PTCA alone produced a decrease in pyrene dimer formation (P less t han or equal to 0.0083) and an increase in light scattering at 650 nm (P le ss than or equal to 0.0128). Treatment with ADP and GPIIb/IIIa receptor ant agonists reduced PTCA induced changes in pyrene dimer formation. An unexpec ted decrease in pyrene dimer formation (P less than or equal to 0.05) was d etected when the GPIIb/IIIa receptor antagonist was given together with an ADP receptor antagonist. Conclusions: 1) Analysis of membrane fluidity provides a sensitive marker f or platelet activation state. 2) Reduced membrane fluidity after combined p latelet inhibitor treatments suggests reduced antiplatelet efficacy. (C) 20 01Wiley-Liss, Inc.