Glossary of Common Thrombic Terms Associated with Blood Clots
Anticoagulant A drug given to prevent blood from excessive clotting; commonly referred to as blood thinner.
Antithrombin III A protein found in our bloodstream. It controls our clotting mechanism and prevents us from excessive clotting. It functions as a naturally occurring mild blood thinner by blocking the last part of our clotting mechanism and inactivates the clotting protein thrombin (= factor IIa); thus, it is called anti-thrombin.
Antithrombin III Deficiency (AT-III) AT-III deficiency is a disorder that increases the risk for blood clots. It can be (a) acquired, or (b) inherited, or (c) based on a misinterpretation of lab tests (values can be temporarily low at the time of the acute clot or during heparin therapy).
Artery Any of the blood vessels that carry blood away from the heart.
CDC The Center for Disease Control and Prevention is a government health care agency whose mission focuses on the prevention and treatment of disease. It is located in Atlanta, Georgia.
Coumadin®A brand name for warfarin, an anticoagulation (blood thinning) medicine.
Deep Vein Thrombosis (DVT) A blood clot anywhere in the deep veins of the body. A DVT occurs most often in the legs, and may break off and travel to other parts of the body, most commonly the lungs.
Economy Class Syndrome -is the occurrence of deep vein thrombosis (DVT) in airline travelers due to cramped conditions compounded by inactivity especially on long haul flights.. The term was first coined in the late 1980's when it was observed that people who had traveled long distances by plane were at an increased risk for blood clots especially DVT resulting often in a pulmonary embolism. Although the correlation between air travel and DVT haad been known for some time, the "syndrome" has received a great deal of press recently and there are even Internet sites devoted to the subject.
Factor V deficiency An inherited bleeding disorder, in which the clotting factor V (five) is low. The disorder is very rare, occurring in only one in one million people. This is not the same as factor V Leiden.
Factor V Leiden (FVL) An inherited blood clotting disorder that is found in 5% of Caucasian Americans, and 1.2% of Afro-Americans. One can be heterozygous (have one abnormal gene), homozygous (have two abnormal genes) or normal (not have any abnormal genes). The genetic test for factor V Leiden has only been available since 1994.
Heparin : A blood thinner given into the vein (i.v.) or
into the skin (s.c.).
Heterozygous Having one abnormal gene. If you are heterozygote
for factor V Leiden you have inherited the trait from one parent.
Homocysteine An amino acid found in the blood. High homocysteine levels are a risk factor for blood clots in the veins (DVT, PE) or arteries (heart attack, stroke), and hardening of the arteries (arteriosclerosis).
Hyperhomocysteinemia A condition where elevated homocysteine levels are present in the blood which may damage the lining of blood vessels, and lead to the formation of blood clots.
Homocystinuria A rare hereditary disease due to a deficiency of an enzyme needed to prevent the build up of homocysteine in the blood.
Homozygous Having two abnormal genes. If you are homozygote for factor V Leiden, you inherited an abnormal gene from both parents.
INR (International Normalized Ratio) INR is a blood test result that helps physicians monitor patients taking anticoagulant medications. The INR is a method of expressing the results of a prothrombin time (PT) blood test. It is based on an international standard that automatically corrects for variations between labs. Thus, using the INR, the PT measurement from one lab can be compared to a PT measurement from any other lab in the world, even if they use different methods to measure PT.
Low Molecular Weight (LMWH) An injectable form of heparin (a blood thinner) that is given underneath the skin. Examples of brand names are Lovenox®, Fragmin®, and Innohep®. LMWH are often used as an alternative to Heparin. LMWH may also be used as bridging therapy in patients on warfarin, when dental work or surgery are needed or during pregnancy.
Lytic therapy A clot busting medication given in the hospital into the blood vessel to break up clots. The treatment has a risk of bleeding. Drug names are tPA, streptokinase, and urokinase.
MTHFR Stands for Methylene-Tetra-Hydro-Folate-Reductase. Some individuals with the homozygous MTHFR mutation have elevated homocysteine levels. Elevated homocysteine levels are a risk factor for blood clots. The individuals with MTHFR mutations who have normal homocysteine levels are not at increased risk for clots. Thus, the MTHFR mutation by itself is not a clotting disorder.
Myocardial Infarction Known as a heart attack. Myocardium = heart muscle; infarct = cell death caused by blocked blood flow; thus, death of an area of heart muscle.
Platelets Small particles in the blood that control bleeding; they form clusters to plug small holes in blood vessels and assist in the clotting process.
Protein C deficiency Protein C deficiency is an uncommon clotting disorder: approximately 1 per 700 people has inherited protein C deficiency. Since we all have two genes for every protein (one from mother and one from father), people can have two normal genes (healthy), one mutated protein S gene (heterozygous), or two mutated genes (homozygous). Individuals with protein C deficiency are typically heterozygous. Homozygous individuals have such a severe clotting problem, that they typically die immediately after birth because of clotting everywhere; this is termed "Purpura fulminans."
Protein C deficiency can be caused by more than 100 different mutations in the protein C gene. This makes genetic testing for the defect very difficult, time-consuming, and expensive; it is therefore not done in routine clinical practice. A few academic institutions with a special interest in protein C deficiency perform genetic testing for research purposes. In some people protein C deficiency is due to acquired (non-inherited) causes, and may be temporary.
Protein S deficiency Protein S deficiency is an uncommon clotting disorder: approximately 1 per 500 to 1 per 3,000 people has inherited protein S deficiency. Since we all have two genes for every protein (one from mother and one from father), people can have two normal genes (healthy), one mutated protein S gene (heterozygous), or two mutated genes (homozygous). Individuals with protein S deficiency are typically heterozygous. Homozygous individuals have such a severe clotting problem, that they typically die immediately after birth because of clotting everywhere; this is termed "Purpura fulminans."
Protein S deficiency can be caused by more than 100 different mutations in the protein S gene. This makes genetic testing for the defect very difficult, time-consuming, and expensive; it is therefore not done in routine clinical practice. A few academic institutions with a special interest in protein S deficiency perform genetic testing for research purposes. In some people protein S deficiency is due to acquired (non-inherited) causes, and may be temporary.
Prothrombin deficiency Prothrombin (= factor II) is 1 of the approximately 15 clotting proteins that is needed to stop us from bleeding. If you are low in prothrombin, you have a tendency to bleed.
Prothrombin 20210 mutation The prothrombin 20210 mutation (= factor II 20210 mutation) is a very common mutation and is a mild risk factor for deep vein thrombosis (DVT) and pulmonary embolism (PE).
PT (Prothrombin Time Test) The prothrombin time test, also called PT, helps measure how well blood is able to clot. The test provides a control for long-term anticoagulant therapy that usually involves the use of warfarin. Also known as INR or Protime.
PTT (Partial Thromboplastin Time) This test is used to evaluate part of the clotting system. It is used to monitor heparin therapy.
Pulmonary Embolism (PE) A clot that is in the blood vessels in the lungs, making it difficult to breathe. Pulmonary embolism may be fatal.
Stroke A condition that occurs when oxygen-rich blood is prevented from reaching an area of the brain; it can lead to death of brain cells in that area.
Thrombophilia A hereditary or acquired predisposition to develop blood clots. It is also referred to as hypercoagulable state or hypercoagulability.
Thrombosis (aka thrombus) A blood clot that forms within a blood vessel. When the blockage occurs in a heart artery, it is called a coronary thrombosis.
Transient Ischemic Attack (TIA) Often called a “mini stroke”, but transient (short term) in nature–symptoms last less than 48 hours.
Vein A blood vessels that carries blood back to the heart
Warfarin A blood thinning medicine. Brand name: Coumadin®