Antithrombotic defense during the postoperative period. Clinical documentation of low molecular weight heparin

The incidence of postoperative thromboembolic complications depends on the type of basic disease, the surgical procedure as well as on various additional risk factors. Without perioperative prophylaxis about 10 to 70% of the patients develop deep vein thrombosis (DVT). After an extensive description of different methods to diagnose DVT, the practical use of the radiofibrinogen uptake test is illustrated by means of a clinical trial on low molecular weight heparin (LMWH). The study consisted in a randomized comparative trial on the peri-/postoperative thrombotic prophylaxis with LMWH 2,500 U s.c. once daily and unfractionated heparin (UFH) 5,000 U s.c. twice daily. 231 patients were recruited from the field of elective surgery and were characterized by a comparatively high postoperative risk of thrombosis. The medication of heparins was supplemented by dihydroergotamine (DHE) 0.5 mg s.c with the advantage to measure the prophylactic potential of short-chain heparin in comparison with UFH/DHE as a highly active antithrombotic regimen. The duration of prophylaxis with applications at 12- and 24-h intervals, respectively, covered a period of at least 7 days. Diagnosis of leg vein thrombosis was performed with the radiofibrinogen uptake test. Under standard prophylaxis with UFH/DHE twice a day 14 patients suffered postoperative thromboses, while with LMWH/DHE once a day only 4 patients suffered thromboses (p less than 0.025). Bleeding complications (wound hematome, re-operations, postoperative blood loss) were equally frequent in both groups and were in the normal range. Other side effects, in particular peripheral vasospasms and anginal attacks, were not observed.