Neutrophil-derived microparticles are released into the coronary circulation following percutaneous coronary intervention in acute coronary syndrome patients

Aims : To evaluate (i) local coronary and systemic levels of microparticles (MP) in Acute Coronary Syndrome (ACS) and Stable Angina Pectoris (SAP) patients and (ii) their release after plaque disruption with percutaneous coronary intervention (PCI). Background: Microparticles are small vesicles originating from plasma membranes of cells after activation or apoptosis and are implicated in the pathogenesis of atherosclerosis. Neutrophils play a role in plaque destabilisation and shed neutrophil-derived microparticles have the potential to drive significant pro-inflammatory and thrombotic downstream effects. Methods: 8 ACS and 8 SAP patients were included. Coronary sinus samples pre-intervention (CS1), 45seconds following balloon angioplasty (CS2) and at 45 second intervals following stent deployment (CS3, CS4, CS5), together with peripheral vein samples, pre and post PCI were analysed for neutrophil-derived (CD66b+), endothelial-derived (CD144+), platelet-derived (CD41a+), monocyte-derived (CD14+), and apoptotic (Annexin V +) microparticles. ELISA for IL-6, Myeloperoxidase (MPO) and P-Selectin was also performed. Results: CD66b+ MP levels were similar in both groups pre-intervention. Post PCI, CS levels rose significantly in ACS but not SAP patients (ACS AUC: 549±83, SAP AUC: 24±29p Conclusions: Acute neutrophil-derived MP release post-PCI occurs in ACS versus stable patients, likely reflective of plaque MP content in vulnerable lesions.