title: Plasma viscosity, functional fibrinogen, and platelet reactivity in vascular surgery patients.
abstract: BACKGROUND
  Platelet reactivity changes with shear stress, which in turn depends on whole blood and plasma viscosity (PV). Platelets interact with fibrinogen during thrombus formation, and fibrinogen is a determinant of PV. The respective role of PV and fibrinogen on platelet function is still unclear.
  
  
  METHODS
  30 patients undergoing vascular surgery were admitted to this study. In each patient we measured PV using a cone-on-plate viscosimeter, functional fibrinogen using thromboelastometry, and platelet reactivity to thrombin receptor activating peptide (TRAP) stimulation using multi-electrode aggregometry. Routine coagulation parameter were measured.
  
  
  RESULTS
  At the univariate analysis, platelet reactivity was positively associated with mean platelet volume (R2 = 0.15, P = 0.033) and PV (R2 = 0.35, P = 0.0006), and negatively associated with serum bilirubin (R2 = 0.20, P = 0.013) and international normalized ratio (INR) (R2 = 0.19, P = 0.017). At the multivariable analysis, only PV (P = 0.001) and INR (P = 0.019) remained independent predictors of platelet reactivity.
  
  
  CONCLUSIONS
  PV is directly and independently associated with platelet reactivity, whereas functional fibrinogen is not. Aspirin treatment is inadequate to correct thrombin-induced platelet aggregation. In presence of hyperviscosity, patients at high cardiovascular risk, may benefit from more aggressive anti-platelet treatments.
authors.forename: Marco
authors.initials: M
authors.lastname: Ranucci
authors.forename: Matteo
authors.initials: M
authors.lastname: Ranucci
authors.forename: Tommaso
authors.initials: T
authors.lastname: Laddomada
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Baryshnikova
authors.forename: Giovanni
authors.initials: G
authors.lastname: Nano
authors.forename: Santi
authors.initials: S
authors.lastname: Trimarchi
mesh_terms: D000368:Aged; D001792:Blood Platelets / Q000276:immunology*; D001809:Blood Viscosity; D002318:Cardiovascular Diseases / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D005340:Fibrinogen / Q000276:immunology*; D006801:Humans; D008297:Male; D015539:Platelet Activation / Q000276:immunology*; D010974:Platelet Aggregation / Q000276:immunology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010979:Platelet Function Tests; D011446:Prospective Studies
chemical_list: D010975:Platelet Aggregation Inhibitors; D005340:Fibrinogen
keywords: Plasma viscosity; fibrinogen; platelet reactivity; thrombin