2. Low molecular weight heparin reduces the risk of venous thromboembolism post SCI more effectively than standard or unfractionated heparin prophylaxis with less bleeding complications. See figure 8 for anticoagulation therapy and other DVT prevention methods.
Heparin acts as an anticoagulant by forming a complex with antithrombin, catalyzing the inhibition of several activated blood coagulation factors: XIIa, XIa, IXa, Xa and thrombin. Bleeding is the most common adverse effect of heparin.
Low Molecular Weight Heparin (LMWH) as ProphylaxisPost SCI
Low-molecular-weight heparin is derived from standard heparin through either chemical or enzymatic depolymerization. Whereas standard heparin has a molecular weight of 5,000 to 30,000 Daltons, LMWH ranges from 1,000 to 10,000 Daltons. LMWH binds less strongly to protein, has enhanced bioavailability, interacts less with platelets and yields a very predictable dose response. The clinical advantages of LMWH include predictability, dose-dependent plasma levels, a long half-life and less bleeding for a given antithrombotic effect. LMWH is administered once or twice daily, both during the high-risk period when prophylaxis for DVT is recommended and also while waiting for oral anticoagulation to take effect in the treatment of DVT. Table 1 shows Generic and Trade-names of Low Molecular Weight Heparin.Danaparoid sodium (Orgaran) is an alternative anticoagulant for patients who develop heparin-induced thrombocytopenia from heparin therapy. Danaparoid is a low molecular weight heparinoid. Its active components consist of heparin sulfate, dermatan sulfate and chondroitin sulfate. The major difference between danaparoid and other low molecular weight heparins (LMWH) is that danaparoid is devoid of heparin or heparin fragments. However, it exerts effects similarly to other LMWHs. Danaparoid acts by inactivating thrombin.
Table 1. Generic and Trade-names of Low Molecular Weight Heparin
LMWH vs. UFH as Prophylaxis for Venous Thromboembolism Post SCI
The most commonly studied LMWH is the prophylaxis of venous thromboembolism post SCI is enoxaparin. Enoxaparin was the first LMWH in the United States. SCIRE found Level 1 evidence that supports low molecular weight heparin, in particular enoxaparin, is more effective in reducing venous thromboembolic events, when compared to the standard subcutaneous heparin prophylaxis. Moreover, the incidence of bleeding complications was less in the LMWH group. There is strong evidence that LMWH in particular enoxaparin is more effective than standard UFH.
For more information please see: Anti-Coagulation for Prophylaxis of DVT Post SCI
Figure 8.This medical illustration exhibit shows methods for preventing deep vein (venous) thrombosis and pulmonary embolism following leg injury and surgery. The steps in this image include early ambulation, post-operatively, with a caption reading: "Therapeutic exercise following surgery reduces the risks of clots forming in the deep veins of the leg." Other steps include performing "foot pump" exercises, contracting the muscles of the lower leg; wearing graduated compression stockings (GCS); using anticoagulant therapy medication (blood thinners); intermittent pneumatic compression devices (IPCD); and surgically installing an inferior vena cava filter device (IVC filter or Greenfield filter) to catch clots in the blood stream before they reach the heart. From Medical Illustration (2010) Nucleus Medical Media, Inc.