[Prevention of thromboembolism in hysterectomies with low molecular weight heparin Fragmin]

Abstract

In comparison to standard heparins, the low-molecular types are said to have equal or better antithrombotic action and--since they affect coagulation less--to induce fewer hemorrhage complications. As they have a longer biologic half-life, a single subcutaneous injection per day is sufficient. In a prospective randomized study patients who had undergone vaginal and abdominal hysterectomy were given either the low-molecular heparin Fragmin (n = 95) or a combination of heparin-dihydergot (n = 98) as prophylaxis against thrombosis. Dosages of Fragmin were 2 X 2500 anti-Xa units on the day of surgery (Day 1) and 1 X 5000 anti-Xa units from Days 2 to 8; the dosage of heparin-dihydergot (HDHE) was 2 X 5000 IU heparin with 0.5 mg DHE from Days 1 to 8. There was no difference between the two groups with regard to the tendency to intraoperative bleeding, the incidence of severe wound hematomas and the postoperative hemoglobin course. Blood quantities in the drains were somewhat higher in the Fragmin group. Hemostasis studies showed that, also in patients on Fragmin, the activated partial thromboblastin time, thrombin time and reaction and clot formation time in the thromboelastogram are significantly prolonged three to four hours after injection. The heparin activity measured as the anti-Xa factor was higher by a factor of ten in patients on Fragmin than in those on HDHE. The thromboserate, recorded thermographically with the DeVeTherm unit, was the same in the two groups. Subjective acceptance of Fragmin prophylaxis was distinctly higher. Further studies to establish the required dose and show the effectiveness of low-molecule heparins seem necessary.