Antithrombotic effect of enoxaparin in clinically healthy cats: a venous stasis model

J Vet Intern Med. 2010 Jan-Feb;24(1):185-91. doi: 10.1111/j.1939-1676.2009.0412.x.


Background: Systemic arterial thromboembolic events are a serious complication of cardiac disease in cats.

Objectives: To determine if enoxaparin induces an antithrombotic effect in cats at a dosage of 1 mg/kg SC q12h and if this antithrombotic effect is predicted by anti-Xa activity.

Animals: Fourteen clinically healthy cats were divided into 3 groups: control (4 cats), treated and assessed at 4 hours (5 cats), and treated and assessed at 12 hours (5 cats).

Methods: A venous stasis model was used and the extent of thrombus formation estimated by measuring thrombus weight and accretion of 125I-fibrinogen. Plasma anti-Xa activity was measured in treated cats.

Results: There was a significant reduction in thrombus formation in the 4 h group compared with control (median weight, 0.000 versus 0.565mg/mm, P < .01; median % 125I-fibrinogen accretion, 0.0 versus 42.0%, P < .01). There was a reduction in thrombus formation in the 12 h group (median weight, 0.006 mg/mm, P = .09; median % 125I-fibrinogen accretion, 3.83%, P = .09) but this reduction was not significant. The median percent thrombus inhibition for treated cats was 100.0% at 4 hours and 91.4% at 12 hours. Plasma anti-Xa activity was not significantly correlated with thrombus formation.

Conclusions and clinical importance: This pilot study demonstrates that enoxaparin, when administered at a dosage of 1 mg/kg SC q12h, produces an antithrombotic effect in a venous statsis model in clinically healthy cats. Furthermore, this study demonstrates that anti-Xa activity is a poor predictor of enoxaparin's antithrombotic effect.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anticoagulants / therapeutic use*
  • Cat Diseases / prevention & control*
  • Cats*
  • Enoxaparin / therapeutic use*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Male
  • Pilot Projects
  • Venous Thrombosis / prevention & control
  • Venous Thrombosis / veterinary*


  • Anticoagulants
  • Enoxaparin