Some patients who have presented a thromboembolic event persist with a high risk of recurrence despite anticoagulant treatment. It has been suggested that adding an inferior vena cava filter may reduce this risk, but the clinical effects of this measure are not clear. To answer this question we searched in Epistemonikos database, which is maintained by screening multiple information sources. We identified three systematic reviews including four randomized trials answering this question. We extracted data, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. We concluded there might be little or no difference on the occurrence of deep venous thrombosis by adding an inferior vena cava filter in anticoagulated patients, and it is not clear whether there are differences in the occurrence of pulmonary embolism or mortality because the certainty of evidence is very low.
This article describes the pharmacology of approved parenteral anticoagulants. These include the indirect anticoagulants, unfractionated heparin (UFH), low-molecular-weight heparins (LMWHs), fondaparinux, and danaparoid, as well as the direct thrombin inhibitors hirudin, bivalirudin, and argatroban. UFH is a heterogeneous mixture of glycosaminoglycans that bind to antithrombin via a unique pentasaccharide sequence and catalyze the inactivation of thrombin, factor Xa, and other clotting enzymes. Heparin also binds to cells and plasma proteins other than antithrombin causing unpredictable pharmacokinetic and pharmacodynamic properties and triggering nonhemorrhagic side effects, such as heparin-induced thrombocytopenia (HIT) and osteoporosis. LMWHs have greater inhibitory activity against factor Xa than thrombin and exhibit less binding to cells and plasma proteins than heparin. Consequently, LMWH preparations have more predictable pharmacokinetic and pharmacodynamic properties, have a longer half-life than heparin, and are associated with a lower risk of nonhemorrhagic side effects. LMWHs can be administered once daily or bid by subcutaneous injection, without coagulation monitoring. Based on their greater convenience, LMWHs have replaced UFH for many clinical indications. Fondaparinux, a synthetic pentasaccharide, catalyzes the inhibition of factor Xa, but not thrombin, in an antithrombin-dependent fashion. Fondaparinux binds only to antithrombin. Therefore, fondaparinux-associated HIT or osteoporosis is unlikely to occur. Fondaparinux exhibits complete bioavailability when administered subcutaneously, has a longer half-life than LMWHs, and is given once daily by subcutaneous injection in fixed doses, without coagulation monitoring. Three additional parenteral direct thrombin inhibitors and danaparoid are approved as alternatives to heparin in patients with HIT.
BACKGROUND: This article addresses the treatment of VTE disease.
METHODS: We generated strong (Grade 1) and weak (Grade 2) recommendations based on high-quality (Grade A), moderate-quality (Grade B), and low-quality (Grade C) evidence.
RESULTS: For acute DVT or pulmonary embolism (PE), we recommend initial parenteral anticoagulant therapy (Grade 1B) or anticoagulation with rivaroxaban. We suggest low-molecular-weight heparin (LMWH) or fondaparinux over IV unfractionated heparin (Grade 2C) or subcutaneous unfractionated heparin (Grade 2B). We suggest thrombolytic therapy for PE with hypotension (Grade 2C). For proximal DVT or PE, we recommend treatment of 3 months over shorter periods (Grade 1B). For a first proximal DVT or PE that is provoked by surgery or by a nonsurgical transient risk factor, we recommend 3 months of therapy (Grade 1B; Grade 2B if provoked by a nonsurgical risk factor and low or moderate bleeding risk); that is unprovoked, we suggest extended therapy if bleeding risk is low or moderate (Grade 2B) and recommend 3 months of therapy if bleeding risk is high (Grade 1B); and that is associated with active cancer, we recommend extended therapy (Grade 1B; Grade 2B if high bleeding risk) and suggest LMWH over vitamin K antagonists (Grade 2B). We suggest vitamin K antagonists or LMWH over dabigatran or rivaroxaban (Grade 2B). We suggest compression stockings to prevent the postthrombotic syndrome (Grade 2B). For extensive superficial vein thrombosis, we suggest prophylactic-dose fondaparinux or LMWH over no anticoagulation (Grade 2B), and suggest fondaparinux over LMWH (Grade 2C).
CONCLUSION: Strong recommendations apply to most patients, whereas weak recommendations are sensitive to differences among patients, including their preferences.
INTRODUCTION: Deep venous thrombosis (DVT) or pulmonary embolism may occur in almost 2 in 1000 people each year, with up to 25% of those having a recurrence. Around 5% to 15% of people with untreated DVT may die from pulmonary embolism. Risk factors for DVT include immobility, surgery (particularly orthopaedic), malignancy, pregnancy, older age, and inherited or acquired prothrombotic clotting disorders.
METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for proximal DVT? What are the effects of treatments for isolated calf DVT? What are the effects of treatments for pulmonary embolism? What are the effects of interventions on oral anticoagulation management in people with thromboembolism? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS: We found 45 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS: In this systematic review we present information relating to the effectiveness and safety of the following interventions: anticoagulation; compression stockings; low molecular weight heparin (short and long term, once or twice daily, and home treatment); oral anticoagulants (short and long term, high intensity, abrupt discontinuation, and computerised decision support); prolonged duration of anticoagulation; thrombolysis; vena cava filters; and warfarin.
BACKGROUND: New treatments are available for treatment of venous thromboembolism. PURPOSE: To review the evidence on the efficacy of interventions for treatment of deep venous thrombosis (DVT) and pulmonary embolism. DATA SOURCES: MEDLINE, MICROMEDEX, the Cochrane Controlled Trials Register, and Cochrane Database of Systematic Reviews from the 1950s through June 2006. STUDY SELECTION: Randomized, controlled trials; systematic reviews of trials; and observational studies; all restricted to English-language articles. DATA EXTRACTION: Paired reviewers assessed study quality and abstracted data. The authors pooled results about optimal duration of anticoagulation. DATA SYNTHESIS: This review includes 101 articles. Low-molecular-weight heparin (LMWH) is modestly superior to unfractionated heparin at preventing recurrent DVT and is at least as effective as unfractionated heparin for treatment of pulmonary embolism. Outpatient treatment of venous thromboembolism is likely to be effective and safe in carefully chosen patients, with appropriate services available. Inpatient or outpatient use of LMWH is cost-saving or cost-effective compared with unfractionated heparin. In observational studies, catheter-directed thrombolysis safely restored vein patency in select patients. Moderately strong evidence supports early use of compression stockings to reduce postthrombotic syndrome. Limited evidence suggests that vena cava filters are only modestly efficacious for prevention of pulmonary embolism. Conventional-intensity oral anticoagulation beyond 12 months may be optimal for patients with unprovoked venous thromboembolism, although patients with transient risk factors benefit little from more than 3 months of therapy. High-quality trials support use of LMWH in place of oral anticoagulation, particularly in patients with cancer. Little evidence is available to guide treatment of venous thromboembolism during pregnancy. LIMITATIONS: The authors could not address all management questions, and excluded non-English-language literature. CONCLUSIONS: The strength of evidence varies across the study questions but generally is strong.
Some patients who have presented a thromboembolic event persist with a high risk of recurrence despite anticoagulant treatment. It has been suggested that adding an inferior vena cava filter may reduce this risk, but the clinical effects of this measure are not clear. To answer this question we searched in Epistemonikos database, which is maintained by screening multiple information sources. We identified three systematic reviews including four randomized trials answering this question. We extracted data, conducted a meta-analysis and generated a summary of findings table using the GRADE approach. We concluded there might be little or no difference on the occurrence of deep venous thrombosis by adding an inferior vena cava filter in anticoagulated patients, and it is not clear whether there are differences in the occurrence of pulmonary embolism or mortality because the certainty of evidence is very low.
