Research discusses whether more people should be tested for FVL genetic blood clotting mutation
By Melanie Hundley
Are you familiar with Factor V Leiden (FAK-tur five LIDE-n)? Or "FVL?" Women, especially those who are not familiar with this genetic condition, those planning pregnancy or considering oral contraceptives or hormone replacement therapy, and those who have a family history of unexplained episodes of forming blood clots, may wish to discuss this with their physician. Men's health may be impacted, too.
However, some physicians may appear hesitant to cooperate with testing because these days it seems to take an act of Congress or Parliament to get a non-standard blood test approved for payment. The blood test is not cheap, but for some, it may offer answers to painful questions that have gone unanswered for years or even save a life.
What is Factor V Leiden?
not newly discovered, and yet, there seems to be very little common knowledge of its existence in the patient community. Research into FVL is ongoing based on the amount of material published in various academic and medical journals including clinical trials. Yet, if FVL is so common, why don't more people know about it? My goal today is to make more people aware of Factor V Leiden, especially women, and encourage physicians to follow their instincts rather than insurance company budgets when considering ordering a test for this condition.
As Mayo's page suggests, it is believed that most people, both men and women, who have the FVL mutation do not experience abnormal blood clotting problems. "Abnormal clotting" here refers to a tendency to form blood clots which may lead to blood clot complications such as deep venous thrombosis (DVT), phlebitis, vascular blockages, strokes, heart attack, pulmonary embolism, etc. FVL does not appear to be associated with the opposite blood condition known as "failure to clot" such as is experienced with hemophilia.
However, a portion of those who have the FVL mutation do have issues with abnormal clotting, and when they do, Mayo says it can "lead to long-term health problems or become life-threatening." They further comment that FVL's association with blood clot forming can be especially concerning for women "during pregnancy or when taking the hormone estrogen." Is FVL one of those things that people do not know about it until it is too late?
A 2003 article on Medicine Net that speaks to defining FVL elaborates a bit more on the genetics involved. Their reference for FVL advises that when someone has only one gene location affected by the FVL mutation, they may have some blood clotting complications. When a human possesses two copies of the FVL mutation in the same area on two of their genes, they are believed to be at a "much higher" risk for the complications associated with FVL.
Medicine Net notes that FVL is the "most common inherited blood clotting disorder in the U.S." and that it impacts about 5% of Caucasians and about 1.2% of African Americans. They add that blood thinning regimens such as heparin or warfarin are used to treat FVL mutation (homozygous). If FVL is an inherited genetic mutation, it is reasonable to assume that some people may also be carriers even if not affected strongly.
Further research on this fascinating genetic condition reveals a bit of intrigue. According to the Factor Five Leiden organization website, FVL has been known about for over 15 years. Yet while researching this topic, I was not able to find one female friend, including those with family histories of blood clotting, who was familiar with FVL. If FVL is so prevalent in the population and its associated complications are known, why isn't there more awareness of this condition in the general public?
I researched the academic and scientific journals for indications of FVL testing in clinical practices (doctors and clinics). I found an article published in 2010 in the European Journal of Human Genetics by researchers associated with the Haukeland University Hospital and the University of Bergen, both in Norway. Blinkenberg et al raised the question about the clinical "usefulness" of the FVL test. Apparently, the FVL test was available in Norway. So available that the question of whether it was cost-effective for publicly funded lab testing was considered a research topic. The results may raise mixed emotions.
According to the discussion in the Blinkenberg et al report, doctors have been performing screening tests for FVL; however, whether screening is based on proven clinical utility is another question. "Clinical utility" appears to reference the cost effectiveness aspect of testing versus medical risk and the test's performance as an indicator for treatment pathways. In other words, is it worth it from a cost perspective?
I must admit, I found this somewhat surprising given the potential risks and complications associated with FVL. Knowing one has FVL may provide life-saving tips to managing those risks. A few FVL-associated preventive medical recommendations are mentioned in the Norwegian article:
- No smoking
- Weight reduction
- Eating healthfully
- Sufficient exercise
- Gradient compression stockings and "ample water intake on long air flights," and
- "Observation" during longer periods of bed rest.
Blinkenberg et al also point out that Factor V Leiden mutation testing is not a routine test that is administered before women are prescribed birth control pills or "hormone replacement therapy." But should it be? If FVL is considered so common, should women who consider these drugs be made clearer about the risks associated with them, especially if they have a predisposition to forming clots? I would imagine that women, including young women, who have experienced a stroke or DVT while taking birth control pills might offer a different opinion on pre-testing. And are there risks for men associated with medications they may be prescribed also?
What Does a Life Impacted By FVL Look Like?
One scenario example of a life impacted by FVL may include:
- Associated lymphedema
- Painful swelling in the affected areas of the body
- Higher risk pregnancies may be experienced, especially with the natural tendency to form clots in the pregnant body
- Expensive prescription gradient compression stockings are often required to support damaged venous flow in affected limbs once clots have been experienced or venous insufficiency is determined
- Daily blood-thinning medications (anticoagulants) may also be necessary and require frequent blood level lab testing, noting that living on anti-coagulants may also introduce risk for excessive bleeding, especially if injured
- Avoiding prolonged sitting or standing
- Avoiding air travel or distance driving without precautions
- Risk of excessive bleeding after cutting injury, surgery, dental work, bruising
- Wearing medical alert jewelry related to clotting disorders and/or medications
- Life long avoidance of birth control pills or hormone replacement therapy may be required
- Stroke or heart attack is a possible higher risk for those with a tendency to form blood clots
- When clots are detected, thrombolytic medications may also be used to dissolve the clots before further damage or death occurs, and
- Thrombosis or blood clots may form in adults or children.
Survey and Results
To address the clinical utility of FVL testing, the Blinkenberg et al research article describes a survey conducted of about 250 physicians affiliated with a Norwegian hospital who had ordered one or more types of testing related to FVL. The responses to the questionnaire indicate FVL testing was used for diagnostic (54%) and predictive testing (46%). Diagnostic testing refers to tests ordered for patients who had experienced blood clotting episodes and were looking for causes. Predictive testing may refer to patients who wanted to know if they were pre-disposed to blood clotting based on other suspicions or concerns, e.g., family history.
The Norwegian survey of physicians found that:
- 20% of the diagnostic testing reported identified FVL presence
- 26% of the preventive testing reported identified FVL presence (and 1/4 of these were administered as risk assessment before prescribing oral contraceptives to women)
The study article contains many more data points of their outcome.
Despite the risks of blood clotting tendencies, apparently there is a debate about the cost and usefulness of medical testing for FVL in the medical community. Blinkenberg et al's report concludes that based on their survey of physicians in their study, testing for FVL "in current practice might do more harm than good," apparently referencing situations where the testing proved a low incidence of FVL in the results which the report seems to consider "unjustified." And it appears the harm they refer to includes financial cost, a prominent factor today's medical practices. They also mention the risk of "false assurance or unnecessary anxiety," and the apparent lack of action taken once FVL is confirmed.
Regardless of cost, I would suggest that the information and understanding about Factor V Leiden genetic mutation risks, testing, and potential treatments should be more commonly discussed and understood in the patient community. The possibly preventable medical issues experienced by FVL patients might outweigh the risks of not knowing. At least now, we are familiar with Factor V Leiden and may pursue more information. There may be additional tests associated with blood clotting factors to be considered.
Family history of abnormal blood clotting or concerns about associated risks may be assessed by a licensed medical physician including consideration for testing and managing Factor V Leiden. More information about thrombophilia awareness may be found at www.fvleiden.org. A very interesting article appeared in CNN Health regarding the blood clot-related death of a news correspondent, David Bloom. The American Heart Association just published a story about siblings and blood clots. Also, Dr. Mark Reding's excellent lecture on blood clotting is presented on Youtube in parts.
Disclaimer: This is an editorial review only, written by a non-medical author, and is subject to change or update. The information and links contained in this article are for educational purposes only to support further inquiry and should not be used for diagnosis or to guide treatment. Any reader who is concerned about his or her health should contact a licensed medical doctor for advice. While every effort is made to ensure accuracy, readers should always refer to the original cited sources for verification and/or any interpretation of source material. Author assumes no liability for content, errors, and/or omissions.
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