title: Prothrombotic changes with acute psychological stress: combined effect of hemoconcentration and genuine coagulation activation.
abstract: BACKGROUND
  Acute psychosocial stress accelerates blood coagulation and elicits hemoconcentration which mechanisms are implicated in acute coronary thrombotic events. We investigated the extent to which the change in prothrombotic measures with acute stress reflects hemoconcentration and genuine activation of coagulation.
  
  
  METHODS
  Twenty-one middle-aged healthy men underwent three sessions of a combined speech and mental arithmetic task with one-week intervals. Coagulation and plasma volume were assessed at baseline, immediately post-stress, and 45 min post-stress at sessions one and three. Measures of both visits were aggregated to enhance robustness of individual biological stress responses. Changes in eight coagulation measures with and without adjustment for simultaneous plasma volume shift were compared.
  
  
  RESULTS
  From baseline to immediately post-stress, unadjusted levels of fibrinogen (p=0.028), clotting factor VII activity (FVII:C) (p=0.001), FVIII:C (p<0.001), FXII:C (p<0.001), and von Willebrand factor (VWF) (p=0.008) all increased. Taking into account hemoconcentration, fibrinogen (p=0.020) and FVII:C levels (p=0.001) decreased, activated partial prothrombin time (APPT) shortened (p<0.001) and prothrombin time (PT) was prolonged (p<0.001). Between baseline and 45 min post-stress, unadjusted (p=0.050) and adjusted (p=0.001) FVIII:C levels increased, adjusted APTT was prolonged (p=0.017), and adjusted PT was shortened (p=0.033). D-dimer levels did not significantly change over time.
  
  
  CONCLUSIONS
  Adjustment for stress-hemoconcentration altered the course of unadjusted levels of several prothrombotic factors. After adjustment for hemoconcentration, APPT was shortened immediately post-stress, whereas 45 min post-stress, FVIII:C was increased and PT was shortened. Procoagulant changes to acute stress may reflect both hemoconcentration and genuine activation of coagulation molecules and pathways.
authors.affiliation: Department of General Internal Medicine, University Hospital / INSELSPITAL, CH-3010 Bern/ Switzerland. roland.vonkaenel@insel.ch
authors.forename: Roland
authors.initials: R
authors.lastname: von Känel
authors.forename: Brigitte M
authors.initials: BM
authors.lastname: Kudielka
authors.forename: André
authors.initials: A
authors.lastname: Haeberli
authors.forename: Monika
authors.initials: M
authors.lastname: Stutz
authors.forename: Joachim E
authors.initials: JE
authors.lastname: Fischer
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Patterson
mesh_terms: D000328:Adult; D001777:Blood Coagulation; D001779:Blood Coagulation Factors / Q000032:analysis / Q000378:metabolism; D006400:Hematocrit; D006439:Hemodynamics; D006801:Humans; D008875:Middle Aged; D010953:Plasma Volume; D013315:Stress, Psychological / Q000097:blood*
chemical_list: D001779:Blood Coagulation Factors