Factor V Leiden

Deep Vein Thrombosis (DVT) Awareness Month is a multi-faceted campaign aimed at raising awareness among consumers, healthcare professionals and policy-makers about DVT and PE on a national and local level.

What is factor V Leiden thrombophilia?

Factor V Leiden thrombophilia is an inherited disorder of blood clotting. Factor V Leiden is the name of a specific mutation (genetic alteration) that results in thrombophilia, or an increased tendency to form abnormal blood clots in blood vessels. People who have the factor V Leiden mutation are at somewhat higher than average risk for a type of clot that forms in large veins in the legs (deep venous thrombosis, or DVT) or a clot that travels through the bloodstream and lodges in the lungs (pulmonary embolism, or PE).

Factor V Leiden is the most common inherited form of thrombophilia. Between 3 and 8 percent of the Caucasian (white) U.S. and European populations carry one copy of the factor V Leiden mutation, and about 1 in 5,000 people have two copies of the mutation. The mutation is less common in other populations.

A mutation in the factor V gene (F5) increases the risk of developing factor V Leiden thrombophilia. The protein made by F5 called factor V plays a critical role in the formation of blood clots in response to injury. The Factor V protein is involved in a series of chemical reactions that hold blood clots together. A molecule called activated protein C (APC) prevents blood clots from growing too large by inactivating factor V. In people with the factor V Leiden mutation, APC is unable to inactivate factor V normally. As a result, the clotting process continues longer than usual, increasing the chance of developing abnormal blood clots.

What are the symptoms of factor V Leiden thrombophilia?

The symptoms of factor V Leiden vary among individuals. There are some individuals who have the F5 gene and who never develop thrombosis, while others have recurring thrombosis before the age of 30 years. This variability is influenced by the number of F5 gene mutation a person has, the presence of other gene alterations related to blood clotting, and circumstantial risk factors, such as surgery, use of oral contraceptives and pregnancy.

Symptoms of Factor V Leiden include:

Having a first DVT or PE before 50 years of age.
Having recurring DVT or PE.
Having venous thrombosis in unusual sites in the body such as the brain or the liver.
Having a DVT or PE during or right after pregnancy.
Having a history of unexplained pregnancy loss in the second or third trimester.
Having a DVT or PE and a strong family history of venous thromboembolism.

The use of hormones, such as oral contraceptive pills (OCPs) and hormone replacement therapy (HRT), including estrogen and estrogen-like drugs) taken after menopause, increases the risk of developing DVT and PE. Healthy women taking OCPs have a three- to four-fold increased risk of developing a DVT or PE compared with women who do not take OCP. Women with factor V Leiden who take OCPs have about a 35-fold increased risk of developing a DVT or PE compared with women without factor V Leiden and those who do not take OCPs. Likewise, postmenopausal women taking HRT have a two- to three-fold higher risk of developing a DVT or PE than women who do not take HRT, and women with factor V Leiden who take HRT have a 15-fold higher risk. Women with heterozygous factor V Leiden who are making decisions about OCP or HRT use should take these statistics into consideration when weighing the risks and benefits of treatment.

Here are some helpful tips to help protect you from DVT:

Stay active.
If you know you’re going to be inactive for an extended period of time, such as during travel, there are sedentary exercises you can do.

Quit smoking, smoking is a risk factor for developing DVT. If you smoke or use smokeless products, quit immediately.

Look for a family history of blood clots.
Clotting disorders may run in the family, research your family medical history to find out more about your risk. A simple blood test will determine if you genetically carry Factor V Leiden.

Create a DVT prevention plan before hospitalization.
Hospitalized patients are eight times more likely to suffer DVT due to lack of mobility.

Talk to your doctor.
Your doctor can help you understand your DVT risks better than anyone. Make sure DVT risk assessment is always part of the conversation.

Why is there an urgent need to make DVT a major health priority?

The following facts and statistics are taken from the website of the Coalition to Prevent Deep-Vein Thrombosis.

According to the American Heart Association, DVT occurs in about 2 million Americans every year.
More people suffer from DVT annually than heart attack and stroke.
Up to 600,000 patients are hospitalized each year for DVT.
Pulmonary embolism causes more deaths annually in the United States than breast cancer, AIDS and highway fatalities (combined).
Fatal PE may be the most common preventable cause of hospital death in the United States.
Only one-third of hospitalized patients with risk factors for blood clots received preventive treatment, according to a U.S. multicenter study.
Without preventive treatment, up to 60 percent of patients who undergo total hip replacement surgery may develop DVT.
Cancer patients undergoing surgical procedures have at least twice the risk of postoperative DVT and more than three times the risk of fatal PE than non-cancer patients undergoing similar procedures.
In the elderly, DVT is associated with a 21 percent one-year mortality rate, and PE is associated with a 39 percent one-year mortality rate.
PE is the leading cause of maternal death associated with childbirth. A woman’s risk of developing Venous Thromboembolism (VTE) is six times greater when she is pregnant.