Reviparin: a review of its efficacy in the prevention and treatment of venous thromboembolism

Reviparin (reviparin sodium) is a low molecular weight heparin (LMWH) that catalyses the inactivation of factors Xa and IIa by binding to antithrombin, which ultimately leads to the inhibition of the clotting cascade. It is administered subcutaneously. Reviparin 7,000 to 12,600 anti-XaIU/day was found to be as effective as intravenous unfractionated heparin in preventing the clinical recurrence of acute deep vein thrombosis (DVT) and/or pulmonary embolism in 1 large randomised, multicentre trial (COLUMBUS) and was significantly more effective than intravenous unfractionated heparin in the prevention of recurrent venous thromboembolism in another large randomised, multicentre trial (CORTES). Reviparin has also been compared with unfractionated heparin in children with established DVT. However, the trial was under-powered and no conclusion could be made regarding comparative efficacy. As prophylaxis, reviparin 1,750 anti-XaIU once daily was as effective as unfractionated heparin 5,000IU twice daily in 1,311 patients undergoing abdominal surgery and, in a once daily dosage of 4,200 anti-XaIU, was as effective as subcutaneous enoxaparin sodium 40 mg/day or acenocoumarol in patients undergoing hip replacement surgery. Reviparin 1,750 anti-XaIU also effectively prevented DVT. compared with no treatment, in patients undergoing knee arthroscopy. It was also more effective than placebo in patients with brace immobilisation of the lower extremity. Reviparin was compared with 'standard care' in children with central venous lines. However, the trial was too small to make conclusions regarding its efficacy. Comparative data indicate that reviparin is at least as well tolerated as heparin and enoxaparin sodium. However, in a large (n = 1,279) trial there were significantly fewer major bleeding episodes in patients receiving reviparin than in patients given the oral anticoagulant acenocoumarol. The most commonly reported adverse events in therapeutic trials have been intraoperative blood loss and postoperative bleeding complications such as wound haematoma, bruising and injection site haemorrhage. Reviparin was also well tolerated in 2 studies in children aged < or = 16 years.

CONCLUSION

Reviparin has shown efficacy in the treatment of established DVT and in the prevention of postoperative DVT after moderate and high risk surgery and was as effective as enoxaparin sodium or acenocoumarol in patients undergoing hip replacement surgery. As an effective and well tolerated antithrombotic agent, reviparin is likely to assume a significant role in the treatment and prevention of DVT, as it appears to have a preferable tolerability profile to subcutaneous heparin after moderate risk surgery and is at least as effective as intravenous heparin in the treatment of established DVT.

Endovascular caval interruption in pregnant patients with deep vein thrombosis of the lower extremity

PURPOSE

The choice of therapy for deep vein thrombosis (DVT) of the lower extremity during pregnancy has been widely debated. Warfarin passes through the placenta to the fetus and may cause fetal complications and/or death. Heparin, in contrast, does not cross the placenta, but its long-term use may be impractical and may increase the risk of bleeding, osteoporosis, and neurologic complications. The use of inferior vena cava filters in pregnancy has only been described as case reports in the English medical literature; therefore, this study reviews our experience on this subject.

METHODS

We analyzed 18 pregnant patients who had Greenfield filters (GFs) inserted for DVT of the lower extremity, pulmonary embolism (PE), or both. The DVT diagnosis was made by means of duplex imaging. Conventional full-dose intravenous heparin was initiated until the filter was inserted, followed by subcutaneous heparin until labor, and continued for 6 weeks postpartum in 13 patients who were breast-feeding. Warfarin was given postpartum in the other five patients.

RESULTS

The mean age of the patients was 25 years. The indications for GF insertion included 3 patients who had a PE while on anticoagulation, 2 patients with significant bleeding caused by anticoagulation, 4 patients with free-floating iliofemoral DVT, 2 patients with heparin-induced thrombocytopenia, and 7 patients with iliofemoropopliteal DVT occurring 1 to 3 weeks before labor, for prophylactic reasons. Fourteen of 18 cases were diagnosed in the third trimester of the patient's pregnancy. Filters were inserted via the right internal jugular vein by means of a cut-down technique in the first four patients (stainless steel filters) and percutaneously in 14 patients. The mean fluoroscopy time during filter insertion was less than 2 minutes. There was no fetal or maternal morbidity or mortality. During long-term follow-up (mean, 78 months), no PE or filter-related complications were encountered.

CONCLUSION

GF insertion in pregnant patients with DVT of the lower extremity is safe and effective. Its prophylactic use in pregnant patients who have extensive iliofemoral DVT right before labor may be justified.