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Peripheral Artery Disease: causes and consequences

Coronary Artery Disease: causes and consequences


This section compares anticoagulation using unfractionated heparin, low molecular weight heparin and heparinoids

  • Unfractionated heparin (UFH) has been used for the prevention and treatment of thrombosis for several decades
  • Heparin is mainly obtained from porcine intestine1
  • UFH is a mixture of sulphated glycosaminoglycans of variable lengths and molecular weights
  • Anticoagulant effects and pharmacological properties vary with the size of the molecules
  • Administered parenterally
  • UFH has limited bioavailability because it binds to plasma proteins, platelets (platelet factor 4), macrophages, and endothelial cells, resulting in a highly variable anticoagulant response2
  • UFH inactivates several coagulation enzymes, including Factors IIa (thrombin), Xa, IXa, XIa, and XIIa, by binding to the cofactor AT2


  • Low molecular weight heparins (LMWHs) are derived from UFH by depolymerization1
  • Each LMWH product has a specific molecular weight distribution that determines its anticoagulant activity and duration of action, so one product cannot always be substituted for another
  • LMWHs in current use globally include enoxaparin, dalteparin, nadroparin, tinzaparin, certoparin, reviparin, ardeparin, parnaparin and bemiparin3
  • Administered subcutaneously for VTE prevention
  • Like UFH, LMWHs inactivate several coagulation enzymes by binding to AT50 but have a lower affinity for binding to proteins other than AT and are, therefore, associated with a predictable dose–response and have fewer non-haemorrhagic side-effects4
  • Because of several clinical advantages, LMWHs have gradually replaced UFH for most indications


  • Danaparoid, available in several countries, is classified as a heparinoid
  • It is composed of sulphated glycosaminoglycans and can be used as an alternative to heparin in patients suffering from an antibody-mediated form of heparin-induced thrombocytopenia2
  • Haines ST, Racine E, Zeolla M. Venous thromboembolism. In: DiPiro J, Talbert R, Yee G et al (eds). Pharmacotherapy: a pathophysiologic approach. 5th edn. New York, NY, USA: McGraw-Hill Companies, Inc.; 2002. p. 337–373. Return to content
  • Hirsh J, Bauer KA, Donati MB et al. Parenteral anticoagulants: American College of Chest Physicians evidence-based clinical practice guidelines (8th Edition). Chest 2008;133:141S–159S. Return to content
  • Bick RL, Frenkel EP, Walenga J et al. Unfractionated heparin, low molecular weight heparins, and pentasaccharide: basic mechanism of actions, pharmacology, and clinical use. Hematol Oncol Clin North Am 2005;19:1–51, v. Return to content
  • Garcia DA, Baglin TP, Weitz JI, Samama MM. Parenteral anticoagulants: antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest 2012;141:e24S–e43S. Return to content

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