PROSPECTIVE RANDOMIZED CLINICAL-STUDY IN GENERAL-SURGERY COMPARING A NEW LOW-MOLECULAR-WEIGHT HEPARIN WITH UNFRACTIONATED HEPARIN IN THE PREVENTION OF THROMBOSIS

A prospective, randomized, controlled clinical trial was performed com paring the antithrombotic efficacy of the low molecular weight heparin LMWH 21-23, (Braun) with an unfractionated heparin in elective genera l surgical patients over an observation period of 7 postoperative days . A total of 230 patients were admitted: 103 (group I) received low mo lecular weight heparin and 100 (group II) low-dose unfractionated hepa rin treatment given subcutaneously. In group I 41 patients (46%) were operated on for malignant disease and in group II 54 patients (54%). D ue to the large amount of great abdominal procedures the intra- and pe rioperative application of hydroxyethyl starch was allowed for volume substitution. None of the patients died due to fatal pulmonary embolis m. In group I four patients revealed positive I-125-labeled fibrinogen uptake (3.9%); two patients belonged to the hydroxyethyl starch subgr oup. In group II five patients displayed a positive fibrinogen uptake (5%); two belonged to the hydroxyethyl starch subgroup. The results of the hemostaseological investigations (e.g., prothrombin time, activat ed partial thromboplastin time, thrombin clotting time, fibrinogen, an tithrombin III, protein C, plasminogen, alpha(2)-antiplasmin , tissue- type plasminogen activator, plasminogen activator inhibitor) revealed no statistically significant differences between groups I and II or th eir subgroups, although a tendency to prolonged clotting times was obs erved. The antifactor Xa activity values, however, displayed a statist ically significant difference between the two groups (P < 0.05). The a ntifactor Xa activity measured up to 0.16 U/ml for the low molecular w eight heparin (group I) and 0.05 U/ml for the unfractionated heparin ( group II) in the postoperative period. Major bleeding complications we re not encountered in this study. Fundamental for the low incidence of thrombosis, the additive administration of hydroxyethyl starch appear ed in almost one-third of the patients in both study groups.