Thrombin generation is associated with extracellular vesicle and leukocytes membranes in acute coronary syndrome.

Background: Acute coronary syndrome (ACS) is caused by arterial thrombosis and is associated with sustained activation of coagulation. Clotting requires interactions of coagulation factors with aminophospholipids (aPL): phosphatidylserine (PS) and phosphatidylethanolamine (PE) on membrane surfaces. The aPL composition of circulating membranes in coronary disease has not been characterized. Furthermore, the contribution of external-facing aPL to elevated thrombotic risk in ACS is unknown. Methods and results: Thrombin generation was measured on platelet, leukocyte and extracellular vesicles (EV) from patients with ACS (n = 24), stable coronary artery disease (CAD, n = 18), risk factor positive (RF, n = 23) and healthy controls (HC, n = 24). The aPL composition on the surface of EV, platelets and leukocytes was determined using lipidomics. Leukocytes, platelets and EV externalized PE- and PS-containing fatty acids ranging from C16:0-20:4. These included both diacyl and plasmalogen forms, with significant increases stimulated by agonist activation. Thrombin generation on the surface of EV and leukocytes was higher in ACS than HC. Also, thrombin generation was higher for EV from CAD and RF, than HC. EV counts were higher in CAD and ACS compared with HC. Thrombin generation correlated positively with plasma EV counts and membrane surface area. Conclusion: The aPL membrane of EV and leukocytes may contribute to the activation of coagulation in CAD and ACS. Targeting EV formation/clearance and the aPL surface of EV and leukocyte membranes represents a novel anti-thrombotic target in CAD and ACS. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by the Wellcome Trust (GW4-CAT fellowship to M.P - 216278/Z/19/Z) and the British Heart Foundation (Programme grant to P.C and V.B.O - RG/F/20/110020). DB is in receipt of a HCRW NHS Research Time Award. VJT was supported in part by the Welsh Government/EU Ser Cymru Programme. AAH is supported by a grant from Kuwait University. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval was from Health and Care Research Wales (HCRW, IRAS 243701; REC reference 18/YH/0502). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors