Volumen: 19 # Number : 2
Publication Date : Mayo - Agosto Year: 2015
Underestimation of dosage of low molecular weight
heparin in an acquired antithrombin deficiency.
Case report
Authors: Rosa C, Zirpoli M, Colimodio D, Grabow S,
Trucco J, Montes de Oca V, Mendizabal M,
Chazarreta D, Rojas M, Aris Cancela M.
Abstract: Published data indicate that in patients with cirrhosis,
monitoring of treatment with low molecular
weight heparin (LMWH) by measuring the anti-factor
Xa activity (anti-Xa) with a reagent without exogenous
addition of AT, is not reliable. Our goal was
to demonstrate the underestimation of the dosage of
LMWH using an assay to measure anti-Xa activity,
with a reagent without exogenous addition of AT in
an oncology patient with non-cirrhotic portal hypertension:
29 years old female patient diagnosed with
hepatocholangiocarcinoma that required the implantation
of 2 stents in retrohepatic vena cava and a
prosthetic porto-cava shunt. Postoperatively he started
anticoagulation with LMWH, not achieving therapeutic
levels. Even with supratherapeutic doses, no
LMWH activity was detected. By presenting total
bilirubin (TB): 36 mg/dl and AT: 26%, the sample
was diluted with normal plasma (NP), to minimize
the possible interference of TB and provide AT in
vitro, but the dosages were unchanged. On day 7 of
treatment with the same dose, it was found: LMWH:
0.13 IU/ml, AT: 31%, TB: 42 mg/dl. The patient improved
and in two weeks was evidenced: LMWH:
0.42 IU/ml, AT: 54%, TB: 41 mg/dl. NP dilutions
were processed and reported: LMWH: 0.64 IU/ml.
A week later the dosages showed: LMWH: 0.68 IU/
ml, AT: 68%, TB: 39 mg/dl and diluting with NP the
same dosage was obtained. We show that in this oncology
patient with acquired AT deficiency, measure
anti-Xa activity with a reagent without exogenous
addition of AT, was not reliable.
Key words: Heparin, Low-Molecular-Weight,
Antithrombin III,
Deficiency
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