Information About Blood Clotting

A wide variety of conditions exist that may lead to thrombosis (clotting)  in both arteries and veins.  This information page briefly reviews some of the more common medical terms and conditions related to thrombosis, along with recommended websites that provide further explanation.

In September, 2008, the U.S. Surgeon General issued a Call to Action to Prevent Venous Thrombosis. This important document is written in understandable language and describes the scope of the problem and what is needed to raise awareness and improve our understanding of this disease. 

Anticoagulation medication
Often referred to as “blood thinners", these medications affect the clotting system to delay the formation of blood clots and either help prevent new clots from forming, or the extension of existing clots.   The most common anticoagulants prescribed are heparin and warfarin.  Heparin is an injectable medication given either as an intravenous drip or as an injection into the fleshy part of the abdomen.  Warfarin, sold under brand names like Coumadin® or Jantoven®, is a tablet that interferes with clotting factors made in the liver and works by decreasing those factors which need Vitamin K to function.  Warfarin is in a class of drugs known as “Vitamin K Antagonists.” 

Since both medications can cause bleeding, close monitoring with laboratory tests is very important, and strict compliance with dose adjustments provided by your health care practitioner is needed.

To learn more about anticoagulants, please click on the links below :          

Warfarin:        
http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682277.html

Heparin:         
http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682826.html

Enoxaparin:
http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601210.html

Blood clot
Also known as a thrombus. A blood clot is a meshwork of the blood clotting protein, fibrin, combined with platelets, cells that help form the clot.  Clots are normally formed as a response to injury of a blood vessel.

Deep Vein Thrombosis (DVT):
A blood clot in one of the major veins of the leg, arm, abdomen or brain.  Veins return blood to the heart after it has delivered oxygen and nutrients to the body.  Clots forming often block the flow of blood, which causes symptoms, depending on the size of the clot and location. 

To learn more about deep vein thrombosis, go to  

http://www.nhlbi.nih.gov/health/dci/Diseases/Dvt/DVT_SignsAndSymptoms.html

Pulmonary Embolism (PE) 
A blood clot in any blood vessel that breaks off and travels is an embolus.  A pulmonary embolus is a clot that has traveled to the lung and has most often come from a deep vein thrombosis in the leg. 

To learn more about pulmonary embolism, go to:
http://www.nhlbi.nih.gov/health/dci/Diseases/pe/pe_what.html

 Prevention of DVT and PE
Steps can be taken to help prevent deep vein thrombosis or pulmonary embolism.  For example, daily physical exercise, maintaining a normal body weight, avoiding sitting or standing in one position for long periods of time, and use of compression support stockings may reduce the risk of blood clot formation.

To learn more about how to prevent deep vein thrombosis and pulmonary embolism, go to
www.preventdvt.org/   OR http://circ.ahajournals.org/cgi/content/full/106/12/1436.

Factor V (five) Leiden:
This is the most common inherited disorder of blood clotting passed from one generation to the next.  It is a genetic mutation of the clotting factor, Factor V, that results in a slightly increased tendency to form blood clots.  People with this genetic mutation are at a somewhat higher risk for deep vein thrombosis, pulmonary embolism, and pregnancy loss (miscarriage) or other pregnancy complications.  Most people with Factor V Leiden mutation never develop either abnormal blood clots or have problems with pregnancy. 
For more information, go to:
http://www.circ.ahajournals.org/cgi/content/short/107/15/e94

Prothrombin 20210 Gene Mutation (also known as factor II mutation):
Prothrombin (factor II) is a clotting protein in the blood required for the blood to form a clot.   Prothrombin is needed to form fibrin, the meshwork of a clot.   A change, or mutation, in the gene that controls prothrombin production causes the body to overproduce this protein, leading to abnormal blood clotting.   People with this gene abnormality have inherited the mutation from a parent. 
For more information, go to:  http://circ.ahajournals.org/cgi/content/full/110/3/e15.

Antiphopholipid Antibody Syndrome
A disorder of the immune system that leads to abnormal blood clotting.  The immune system produces antibodies, or substances that attack invading proteins, such as bacteria or viruses.  When the immune system produces antibodies that attack a person’s own body, this is known as an auto-immune disorder.  When antibodies mistakenly attack proteins in the blood stream, in antiphospholipid syndrome, clots may form in the arteries or veins, leading to serious complications such as deep vein thrombosis, pulmonary embolism, stroke or less commonly, heart attack. Pregnant women with this disorder may have miscarriage or stillbirth.
For more information go to: http://www.circ.ahajournals.org/cgi/content/full/112/3/e39

Post-thrombotic syndrome
Many people develop long-term symptoms in their leg after a deep vein thrombosis. These can include pain, swelling and skin problems.