A novel point-of-care assay for the monitoring of low-molecular weight heparins in the cardiac catheterization laboratory.
BACKGROUND
We designed a study to compare the novel point-of-care assay Hemonox clotting time (Hemonox-CT) with the activated clotting time (ACT) and anti-Xa activity to monitor the anticoagulation effects of enoxaparin and dalteparin during percutaneous coronary intervention (PCI).


METHODS
A total of 90 patients undergoing cardiac catheterization were assigned to intravenous (IV) enoxaparin 0.5 mg/kg, dalteparin 50 international units/kg or unfractionated heparin (UFH) 50 units/kg. We measured Hemonox-CT, ACT and plasma anti-Xa levels after serial sampling.


RESULTS
Baseline Hemonox-CT was similar in the enoxaparin (68 +/- 9 sec) and dalteparin (68 +/- 7 sec) groups with no detectable anti-Xa activity at baseline. Minutes after IV administration of enoxaparin and dalteparin, the mean Hemonox-CT increased to 171 +/- 60 sec and 214 +/- 70 sec for both groups, respectively. UFH induced a higher Hemonox-CT response (800 +/- 243 sec). At all time points, Hemonox-CT was higher than the ACT. Peak Hemonox-CT was associated with a therapeutic anti-Xa activity ranging from 0.50 to 1.35 U/ml (mean 0.89 U/ml) for the enoxaparin group and 0.69 to 1.48 U/ml (mean 0.91 U/ml) for the dalteparin group. After reaching peak levels, there was a gradual and parallel decline in Hemonox-CT and anti-Xa activity. The enoxaparin and dalteparin-treated patients successfully underwent PCI without major hemorrhagic complications.


CONCLUSIONS
The Hemonox-CT has better sensitivity to both enoxaparin and dalteparin than does the ACT. Also, Hemonox-CT correlates with anti-Xa activity after IV administration. Hemonox-CT may become an important tool to monitor the anticoagulation effects of low-molecular weight heparin during PCI. Additional studies are needed to determine the target Hemonox-CT.
Marmur
Jonathan D
JD
Department of Cardiology, SUNY Health Sciences Center at Brooklyn, 450 Clarkson Avenue, Box 1257, Brooklyn, NY 11203, USA. jonathan@marmur.com
Lakhani
Manish
M
El Rouby
Soumaya
S
Cavusoglu
Erdal
E