Influence of Low Molecular Weight Heparin on the Hemostatic System After Abdominal Surgery

The hemostatic effect of two low molecular weight heparin fractions and of one unfractionated heparin preparation administered subcutaneously b. i. d. was examined in 6 healthy subjects and in 53 patients after major abdominal surgery. Among other tests platelet count, prothrombin time, fibrinogen, β-thrombo- globulin, antithrombin, antiplasmin, FPA and F-CB 3 related antigen, as well as various heparin activities, were repeatedly determined pre- and postoperatively. Under all tested conditions the low molecular weight fractions induced higher heparin levels, both in terms of anti-Xa and of anti-thrombin activity. No further significant differences of the laboratory results between the treatment groups were documented. Total blood loss measured at the first postoperative day was higher in patients with malignancy and negatively correlated with antithrombin and antiplasmin levels, while no relation was observed with the heparin activities and the other tested parameters. Whereas evidence for a hemorrhagic property of the tested low molecular weight heparin fractions was found, a particular mechanism underlying this effect could not be identified.

Efficacy and safety of a low-molecular-weight heparin and standard unfractionated heparin for prophylaxis of postoperative venous thromboembolism: European multicenter trial

A randomized, double-blind multicenter trial was performed to compare the safety and efficacy of a new low-molecular-weight heparin (LMWH) (LU 47311, Clivarine) and standard unfractionated heparin for the prophylaxis of postoperative venous thromboembolism. Altogether 1351 patients scheduled to undergo abdominal surgery were included. Main outcome measures included the incidence of thromboembolic events (deep vein thrombosis, pulmonary embolism, or both) and bleeding complications, including wound hematoma. A total of 655 patients received 1750 anti-Xa IU of LMWH plus a placebo injection daily; 677 patients received 5000 IU of unfractionated heparin (UFH) twice a day. Both drugs were found to be equally effective, as 4.7% of patients in the LMWH group and 4.3% in the UFH group developed postoperative thromboembolic complications. However, the incidence of bleeding complications was significantly reduced in the LMWH group: 55 (8.3%) patients in the LMWH group and 80 (11.8%) in the UFH group developed bleeding complications, a relative risk (RR) of 0.70 (95% CI 0.51-0.97;p = 0.03); wound hematoma occurred in 29 (4.4%) of the LMWH group compared with 55 (7.7%) in those in the UFH group for an RR of 0.57 (95% CI 0.37-0.88;p = 0.01). This study confirmed that a very low dose of 1750 anti-Xa IU daily of this new LMWH is as effective as 10,000 IU of UFH for preventing postoperative deep vein thrombosis. At this dose its administration is associated with a significant reduction in the risk of bleeding including wound hematoma.

[Pneumonia following bronchography]

The extravasation of contrast medium into the alveoli during or following bronchography would appear to be associated with an increased complication rate. The histomorphological changes occurRing may vary in degree, and it may thus be difficult to differentiate such changes from those associated with other forms of pneumonia and pneumoconiosis. This paper reports on a case in which, using energy-dispersive X-ray micro-analysis in the scanning electron microscope, the presence of contrast medium within a region of alveolar pneumonia was observed, thus enabling accurate establishment of the cause of this condition.

Influence of low molecular weight heparin on the hemostatic system after abdominal surgery

The hemostatic effect of two low molecular weight heparin fractions and of one unfractionated heparin preparation administered subcutaneously b.i.d. was examined in 6 healthy subjects and in 53 patients after major abdominal surgery. Among other tests platelet count, prothrombin time, fibrinogen, beta-thromboglobulin, antithrombin, antiplasmin, FPA and F-CB 3 related antigen, as well as various heparin activities, were repeatedly determined pre- and postoperatively. Under all tested conditions the low molecular weight fractions induced higher heparin levels, both in terms of anti-Xa and of anti-thrombin activity. No further significant differences of the laboratory results between the treatment groups were documented. Total blood loss measured at the first postoperative day was higher in patients with malignancy and negatively correlated with antithrombin and antiplasmin levels, while no relation was observed with the heparin activities and the other tested parameters. Whereas evidence for a hemorrhagic property of the tested low molecular weight heparin fractions was found, a particular mechanism underlying this effect could not be identified.

Clinical efficacy of low molecular weight heparin in postoperative thrombosis prophylaxis

In a randomized controlled clinical trial, the efficacy and safety of two low molecular weight heparin ( LMWH ) fractions in the prophylaxis of deep vein thrombosis (DVT) were assessed. One hundred twenty-six patients undergoing major abdominal surgery received alternatively 2,500 APTT units b.i.d. of two LMWH fractions or 5,000 APTT units b.i.d. of an unfractionated sodium mucosal heparin ( UFH ). LMWH 2 differed from LMWH 1 by presenting a lower mean molecular weight and a higher anti-Xa/APTT ratio in vitro. Patients were randomly allocated to the three groups, and the development of DVT was studied with the 125I-fibrinogen uptake test ( RFUT ). The study was interrupted and the code broken prematurely because of otherwise unexplainable bleeding events. While no thrombosis and no severe bleeding were detected in the UFH group, three (7%) RFUT -positive DVT and two (5%) hemorrhagic complications occurred in the LMWH 1 group. No thrombosis and nine (22%) cases of severe bleeding were observed in the LMWH 2 group. Thus, the latter group differed significantly from the control group with regard to subjective and objective criteria for postoperative bleeding. Although these results do not allow general conclusions as to the value of LMWH fractions in the prevention of DVT, they indicate that these preparations just as ordinary heparin have a limited therapeutic range.