title: Levels of circulating procoagulant microparticles in nonvalvular atrial fibrillation.
abstract: Circulating procoagulant microparticles (MPs) arising from cell activation or fragmentation during apoptosis retain procoagulant properties and are increased in severe thrombotic states. We investigated whether circulating procoagulant MP levels would be increased in nonvalvular atrial fibrillation (AF). Using a hospital case-control study design, circulating procoagulant MP levels were measured in 45 patients with permanent and/or persistent AF who were not receiving anticoagulant therapy and 90 age-matched control subjects (45 with cardiovascular risk factors and 45 without). Annexin V-positive MP levels (expressed as nanomoles per liter of phosphatidylserine equivalent) were higher in patients with AF (median 9.3, interquartile range 6.8 to 17.3 nmol/L) than in control subjects with cardiovascular risk factors (median 4.9, interquartile range 3.7 to 8.4 nmol/L) and control subjects without cardiovascular risk factors (median 3.2, interquantile range 2.3 to 4.6 nmol/L; p<0.001). Platelet-derived MPs (captured with antiglycoprotein Ib) and endothelial-derived MPs (captured with anti-CD31) were similar in patients with AF and control subjects with cardiovascular risk factors but were significantly higher than in control subjects without cardiovascular risk factors. On multiple regression analysis, the presence of AF was a strong predictor of annexin V-positive MP level (p<.001). In conclusion, circulating procoagulant MPs are increased in persistent and/or permanent AF and might reflect a hypercoagulable state that could contribute to atrial thrombosis and thromboembolism.
authors.affiliation: Cardiology Department, Saint-Antoine University and Medical School, Université Pierre et Marie Curie, and INSERM U689, Hôpital Lariboisière, Paris, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Ederhy
authors.forename: Emanuele
authors.initials: E
authors.lastname: Di Angelantonio
authors.forename: Ziad
authors.initials: Z
authors.lastname: Mallat
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Hugel
authors.forename: Sandra
authors.initials: S
authors.lastname: Janower
authors.forename: Catherine
authors.initials: C
authors.lastname: Meuleman
authors.forename: Franck
authors.initials: F
authors.lastname: Boccara
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Freyssinet
authors.forename: Alain
authors.initials: A
authors.lastname: Tedgui
authors.forename: Ariel
authors.initials: A
authors.lastname: Cohen
mesh_terms: D000368:Aged; D017304:Annexin A5 / Q000097:blood; D001281:Atrial Fibrillation / Q000097:blood*; D001779:Blood Coagulation Factors / Q000032:analysis*; D002318:Cardiovascular Diseases / Q000097:blood; D016022:Case-Control Studies; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D012307:Risk Factors; D019851:Thrombophilia / Q000097:blood