[Comparison of 2 low molecular weight heparins in patients undergoing major abdominal surgery]

Thromboembolic disease can, in a large number of cases, be prevented in patients undergoing major surgery by using low molecular weight heparin (LMWH). These molecules extracted from standard heparin using a variety of cleavage methods possess different physical and chemical characteristics. The aim of this study was to compare two LMWH in the prevention of thromboembolism and in terms of safety.

Thirty patients of both sexes were admitted to the study and underwent major abdominal surgery. Fifteen patients were treated with dalteparin sodium, 2500 IU, and fifteen with nadroparin calcium, 3075 IU. Subcutaneous administration was commenced two hours prior to surgery and continued for at least five days after the operation until the complete mobilisation of the patient. Six blood samples were taken from each patient in order to assay: aPTT, heparin, X factor, Quick time, ATIII, platelets and hemoglobin. Intraoperative bleeding and drainage were recorded for each patient.

The group treated with nadroparin showed a significant reduction in hemoglobin, correlated with greater blood loss (p < 0.05) compared to the group treated with dalteparin.

Both nadroparin and dalteparin showed good anti-Xa activity and safety, but although they possess the same pharmacodynamic characteristics, they should not be regarded as equal or interchangeable.