Antithrombotic effect of enoxaparin in clinically healthy cats: a venous stasis model.
BACKGROUND
Systemic arterial thromboembolic events are a serious complication of cardiac disease in cats.


OBJECTIVE
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.


METHODS
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
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.
Van De Wiele
C M
CM
School of Veterinary Medicine, Purdue University, VCS- Lynn Hall, 625 Harrison Street, West Lafayette, IN 47907-2026, USA.
Hogan
D F
DF
Green
H W
HW
Sederquist
K D
KD
D000818:Animals; D000925:Anticoagulants / Q000627:therapeutic use*; D002371:Cat Diseases / Q000517:prevention & control*; D002415:Cats; D017984:Enoxaparin / Q000627:therapeutic use*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D008297:Male; D010865:Pilot Projects; D020246:Venous Thrombosis / Q000517:prevention & control / Q000662:veterinary*
D000925:Anticoagulants; D017984:Enoxaparin