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Direct antithrombins: new perspectives in cardiovascular medicine
1Department of Cardiology, Policlinico San Matteo IRCCS, Pavia, Italy. m.lettino@smatteo.pv.it
Current Medicinal Chemistry. Cardiovascular and Hematological Agents
|August 24, 2004
Summary
New direct thrombin inhibitors like hirudin and bivalirudin show superior efficacy over heparin in preventing arterial and venous thrombosis, with comparable bleeding risks. Oral agents like melagatran also show promise.
Area of Science:
- Pharmacology
- Cardiovascular Medicine
- Hematology
Background:
- Thrombin plays a central role in thrombosis by converting fibrinogen to fibrin and activating platelets.
- Heparin is a widely used anticoagulant, but limitations have driven the development of direct thrombin inhibitors.
- Direct thrombin inhibitors offer targeted antithrombotic therapy with potential advantages over existing treatments.
Purpose of the Study:
- To review the efficacy and safety of direct thrombin inhibitors compared to heparin in various thrombotic conditions.
- To evaluate the clinical utility of parenteral (hirudin, bivalirudin, argatroban) and oral (ximelagatran/melagatran) antithrombins.
- To assess the role of these novel agents in arterial and venous thromboembolism, acute coronary syndromes, and periprocedural anticoagulation.
Main Methods:
- Systematic review of clinical trials evaluating direct thrombin inhibitors.
- Comparison of efficacy and safety endpoints (e.g., major adverse cardiac events, bleeding) against heparin and low molecular weight heparin (LMWH).
- Analysis of data from studies in acute coronary syndromes, percutaneous coronary intervention, venous thromboembolism prophylaxis, and atrial fibrillation.
Main Results:
- Hirudin and bivalirudin demonstrated superior efficacy to heparin in reducing major cardiac events in acute coronary syndromes and improving outcomes in percutaneous coronary angioplasty.
- Hirudin showed significant benefits over unfractionated heparin and LMWH in preventing venous thromboembolism post-arthroplasty, with similar major bleeding rates.
- Preliminary data suggest melagatran/ximelagatran are effective for venous thromboembolism prophylaxis and preventing arterial embolism in non-valvular atrial fibrillation.
Conclusions:
- Direct thrombin inhibitors, including hirudin and bivalirudin, represent a significant advancement over heparin for managing arterial and venous thromboembolic disorders.
- These agents offer improved efficacy in specific cardiovascular and surgical settings, with acceptable safety profiles regarding bleeding.
- Oral direct thrombin inhibitors hold promise for long-term anticoagulation and prophylaxis, potentially offering a safer alternative to warfarin in certain patient populations.