Unfractionated heparin (UH) is a heterogenous preparation of anionic, sulfated glycosaminoglycan polymers with weights ranging from 3000 to 30,000 Da. It is a naturally occurring anticoagulant released from mast cells. It binds reversibly to antithrombin III (ATIII) and greatly accelerates the rate at which ATIII inactivates coagulation enzymes thrombin (factor IIa) and factor Xa. UH is different from low molecular weight heparin (LMWH) in the following ways: the average molecular weight of LMWH is about 4.5 kDa whereas it is 15 kDa for UH; UH requires continuous infusions; activated partial prothrombin time (aPTT) monitoring is required when using UH; and UH has a higher risk of bleeding and higher risk of osteoporosis in long term use. Unfractionated heparin is more specific than LMWH for thrombin. Furthermore, the effects of UH can typically be reversed by using protamine sulfate.
Unfractionated heparin is indicated for prophylaxis and treatment of venous thrombosis and its extension, prevention of post-operative deep venous thrombosis and pulmonary embolism and prevention of clotting in arterial and cardiac surgery. In cardiology, it is used to prevent embolisms in patients with atrial fibrillation and as an adjunct antithrombin therapy in patients with unstable angina and/or non-Q wave myocardial infarctions (i.e. non-ST elevated acute coronary artery syndrome) who are on platelet glycoprotein (IIb/IIIa) receptor inhibitors. Additionally, it is used to prevent clotting during dialysis and surgical procedures, maintain the patency of intravenous injection devices and prevent in vitro coagulation of blood transfusions and in blood samples drawn for laboratory values.
CHU Toulouse, Toulouse 9, France
CH de Valenciennes, Valenciennes, France
CH ARRAS, Arras, Boulevard Georges Besnier, France
The fist Affiliated Hospital Harbin Medical University, Haerbin, Heilongjiang, China
Xiangya Third Hospital of Central South University, Changsha, Hunan, China
First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
University of Colorado Denver, Aurora, Colorado, United States
Diagnostic Clinic of Houston, Houston, Texas, United States
Riverside Nephrology Physicians/Van Buren Dialysis center, Riverside, California, United States
North America Research Institute, San Dimas, California, United States
IC Study, LLC, Escondido, California, United States
Rutgers Women's Health Clinic, New Brunswick, New Jersey, United States
University of California San Diego, San Diego, California, United States
Hopital Ambroise Paré, Boulogne Cedex, France
Hospital Lariboisière, Paris, France
VUMC Amsterdam, Amsterdam, Netherlands
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