Which of the following statement best explains this finding?
A 48-year-old woman, who had been suffering from breast cancer for two years, was admitted to the hospital with the diagnosis of deep venous thrombosis. An IV loading dose of heparin was administered followed by an IV infusion. After 6 hours of heparin therapy, the patient’s activated partial thromboplastin time (aPTT) had not increased relative to her heparin pre-treatment levels.
A. The patient had high plasma levels of heparin-binding proteins B. The patient therapy included a vitamin K supplement C. Heparin has a very short half-life D. Heparin effects are delayed at least 12 hours after administration E. The patient had high plasma levels of antithrombin-III
The patient had high plasma levels of heparin-binding proteins-learning objective: explain the main reasons for heparin resistance. answer: a
the lack of action of heparin in the present case was most likely due to heparin resistance.
heparin can bind to different plasma proteins including platelet factor 4, fibrinogen, factor viii etc. as many heparin-binding proteins are acute-phase reactants, the phenomenon of heparin resistance is often encountered in acutely ill patients or in patients with malignancy, like in the present case.
b) vit k does not affect the anticoagulant action of heparin
c) the half life of heparin is dose dependent and is 30-150 min at therapeutic doses.
d) heparin effect is immediate after iv injection, or delayed 20-60 min after sc injection.
e) heparin resistance can occur with very low, not high, levels of antithrombin iii. this deficiency is a rare hereditary