Fluorescence spectroscopic analysis of circulating platelet activation during coronary angioplasty

Background and Objective Platelet activation during percutaneous transluminal coronary angioplasty (PTCA) initiates thrombus formation and plaque regrowth at sites of arterial injury, limiting procedure efficacy. We have developed a simple assay for circulating platelet activation based on fluorescence 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 platelet inhibitors. Results PTCA alone produced a decrease in pyrene dimer formation (P0.0083) and an increase in light scattering at 650 nm (P0.0128). Treatment with ADP and GPIIb/IIIa receptor antagonists reduced PTCA induced changes in pyrene dimer formation. An unexpected decrease in pyrene dimer formation (P0.05) was detected when the GPIIb/IIIa receptor antagonist was given together with an ADP receptor antagonist. Conclusions 1) Analysis of membrane fluidity provides a sensitive marker for platelet activation state. 2) Reduced membrane fluidity after combined platelet inhibitor treatments suggests reduced antiplatelet efficacy. Lasers Surg. Med. 39:414–426, 2001. © 2001 Wiley‐Liss, Inc.