title: Detection of tissue factor antigen and coagulation activity in coronary artery thrombi isolated from patients with ST-segment elevation acute myocardial infarction.
abstract: BACKGROUND
  Although ruptured atherosclerotic plaques have been extensively analyzed, the composition of thrombi causing arterial occlusion in patients with ST-segment elevation acute myocardial infarction has been less thoroughly investigated. We sought to investigate whether coagulant active tissue factor can be retrieved in thrombi of patients with STEMI undergoing primary percutaneous coronary intervention.
  
  
  METHODS
  Nineteen patients with ST-segment elevation acute myocardial infarction referred for primary percutaneous coronary intervention were enrolled in this study. Coronary thrombi aspirated from coronary arteries were routinely processed for paraffin embedding and histological evaluation (4 patients) or immediately snap frozen for evaluation of tissue factor activity using a modified aPTT test (15 patients). Immunoprecipitation followed by immunoblotting was also performed in 12 patients.
  
  
  RESULTS
  Thrombi aspirated from coronary arteries showed large and irregular areas of tissue factor staining within platelet aggregates, and in close contact with inflammatory cells. Some platelet aggregates stained positive for tissue factor, whereas others did not. Monocytes consistently stained strongly for tissue factor, neutrophils had a more variable and irregular tissue factor staining, and red blood cells did not demonstrate staining for tissue factor. Median clotting time of plasma samples containing homogenized thrombi incubated with a monoclonal antibody that specifically inhibits tissue factor-mediated coagulation activity (mAb 5G9) were significantly longer than their respective controls (88.9 seconds versus 76.5 seconds, respectively; p<0.001). Tissue factor was also identified by immunoprecipitation in 10 patients, with significant variability among band intensities.
  
  
  CONCLUSIONS
  Active tissue factor is present in coronary artery thrombi of patients with ST-segment elevation acute myocardial infarction, suggesting that it contributes to activate the coagulation cascade ensuing in coronary thrombosis.
authors.affiliation: Dipartimento Cardiovascolare, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Tullio
authors.initials: T
authors.lastname: Palmerini
authors.affiliation: Dipartimento Cardiovascolare, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Luciana
authors.initials: L
authors.lastname: Tomasi
authors.affiliation: Dipartimento Cardiovascolare, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Barozzi
authors.affiliation: Dipartimento Cardiovascolare, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Della Riva
authors.affiliation: Dipartimento Cardiovascolare, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mariani
authors.affiliation: Dipartimento Cardiovascolare, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Nevio
authors.initials: N
authors.lastname: Taglieri
authors.affiliation: Istituto di Patolgia, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Ornella
authors.initials: O
authors.lastname: Leone
authors.affiliation: Dipartimento di Radiologia e Scienza Istopatologiche, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Ceccarelli
authors.affiliation: Dipartimento di Malattie Cardiovascolari, Ospedale Civile, Legnano, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: De Servi
authors.affiliation: Dipartimento Cardiovascolare, Policlinico S. Orsola, Bologna, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Branzi
authors.affiliation: Columbia University Medical Center and the Cardiovascular Research Foundation, New York, New York, United States of America.
authors.forename: Philippe
authors.initials: P
authors.lastname: Genereux
authors.affiliation: Columbia University Medical Center and the Cardiovascular Research Foundation, New York, New York, United States of America.
authors.forename: Gregg W
authors.initials: GW
authors.lastname: Stone
authors.affiliation: Laboratory of Blood and Vascular Biology, The Rockefeller University, New York, New York, United States of America.
authors.forename: Jasimuddin
authors.initials: J
authors.lastname: Ahamed
mesh_terms: D000368:Aged; D003328:Coronary Thrombosis / Q000378:metabolism*; D003331:Coronary Vessels / Q000378:metabolism*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000378:metabolism*; D013925:Thromboplastin / Q000378:metabolism*
chemical_list: D013925:Thromboplastin