title: Heparin-neutralizing activity in the plasma of women with gynecologic malignancy: the effect of tumor stage on heparin concentration and fibrin generation after low-dose heparin.
abstract: The relationship between tumor stage and the concentration of circulating heparin achieved after subcutaneous administration and its effect on fibrin generation were studied in 24 women with gynecologic malignancy. A single subcutaneous injection of 5000, 7500, and 10,000/U of sodium heparin was given in random order on different days. Plasma specimens for antithrombin III, fibrinopeptide A, and heparin were obtained serially over an 11-hour interval. Women with a Stage III or IV malignancy had significantly lower circulating heparin after the 5000 and 10,000/U doses. There was a significant decline in fibrinopeptide A as the concentration of circulating heparin increased. Thirty-three percent of women with a Stage III or IV malignancy had no detectable circulating heparin at any point examined over the 11 hours after 5000/U of heparin. Likewise, 16.7% and 8.4% had no detectable circulating heparin after 7500 and 10,000/U, respectively. A similar percentage was noted in a smaller group of women with Stage II malignancy. Next, a known quantity of heparin was added to the plasma from these patients and the concentration of heparin was determined. A significant amount of heparin-neutralizing activity was documented. We conclude that a large percentage of women with an advanced gynecologic malignancy are able to neutralize heparin administered for the prevention of thromboembolic disease. This heparin-neutralizing activity may account for the failure of low-dose heparin to prevent thromboembolic complications in this patient population.
mesh_terms: D000990:Antithrombin III / Q000032:analysis; D005260:Female; D005337:Fibrin / Q000032:analysis*; D005344:Fibrinopeptide A / Q000032:analysis; D005833:Genital Neoplasms, Female / Q000097:blood* / Q000150:complications; D006493:Heparin / Q000008:administration & dosage / Q000097:blood*; D006801:Humans; D013923:Thromboembolism / Q000517:prevention & control
chemical_list: D005344:Fibrinopeptide A; D000990:Antithrombin III; D005337:Fibrin; D006493:Heparin