Deep Vein Thrombosis
By rianna lee sing
Deep Vein Thrombosis is more commonly called DVT. It is also called venous thromboembolism, thrombo phlebitis or phlebothrombosis. According to www.innohepusa.com, DVT is the formation of a blood clot (thrombus) in one of the deep veins of the body, in the leg or pelvis. It is a potentially serious yet treatable condition. The website also breaks down DVT’s components for a deeper understanding:
Deep Vein: Although blood clots can occur in any blood vessel, they commonly occur in the veins deep inside leg, hips and pelvis muscles. These vessels carry blood to the heart from the body’s tissues .
Thrombosis: Normally, clotting protects a wound, like a cut, from excessive bleeding. However, if the tender balance between the substances that encourage blood clot formation and those which inhibit it is upset, blood clots form freely. This is what is referred to as thrombosis.
A Closer Look at Clotting
In Human Diseases and Conditions, Neil Izenberg describes clotting as the process that changes blood in the body from free-flowing liquid into a thick, jellylike substance that stops bleeding. He further describes how clots forms. Almost as soon as blood starts to flow from a cut or scrape, platelets begin to gather. Platelets are clear blood cells that start the process of clotting. However, platelets cannot completely stop the flow of blood. Proteins in the blood plasma (which is the yellow-tinted portion of the blood that also contains water and other substances and carries blood cells and nutrients) are called ‘clotting factors”. They react with calcium to create a thick mass of jellylike material that plugs the cut.
Dangers of DVT
DVT on its own does not threaten life but it is connected with complications which to lead to death. Griffith’s Five Minute Clinical Consult lists the possible complications:
Pulmonary embolism which happens in the majority of cases. A piece of the clot embedded in the leg vein separates and travels through the body to the lung where it lodges itself and blocks the coronary artery. When this happens, sever breathing difficulties occur. More infrequently, a part of the clot may also settle in other organs such as the brain, which causes a stroke.
Post-thrombotic syndrome. This affects many patients who suffer from DVT, because of damage to the valves along the length of the vein.
Systematic embolism where there is arteriovenous stunting. This is a rare complication.
Chronic venous Insufficiency
Post Phlebetic Syndrome
Soft tissue ischemia associated with massive clots and very high venous pressures. This constitutes a surgical emergency.
In the Oxford Textbook of Medicine, Greaves and Taberrer (1996) state that DVT can also occur in the mesenteric, hepatic, cerebral, portal and renal vessels as well as the inferior vena cava.
Symptoms of DVT
The website www.hcd2.bupa.co.uk states that when a clot forms ,two possibilities arise: it can either partially or wholly oppose blood flow in the vein. British United Provident Association’s (BUPA) Health Information Team (2003) lists the symptoms as follows:
swelling of the leg
warmth and redness of the leg
tenderness in the leg
pain that is noticeable or worse when standing or walking
sometimes, some surface veins are more visible through the skin
It is imperative to note that less than 50% of those affected with DVT experience symptoms. It is a ‘silent’ condition.
Symptoms of Pulmonary Embolism
BUPA also lists these as:
shortness of breath
chest pain which may be worsened by deep breaths
coughing up phlegm, possibly specked with blood
Detection of DVT
If DVT is suspected, the doctor will take a full medical history and perform a physical examination. Www.healthatoz.com describes the required tests that follow:
Ultrasound Scan- This is the most commonly used method of detection today. Scientists believe they can detect the smallest clots through ultrasounds
Blood Test- A certain blood test measures the level of a by-product of clotting material called D-dimer
Venography- This is the most accurate test but it is not used much because it is painful, expensive, exposes the patient to radiation and can cause reactions and complications. It identifies the location, extent and degree of blood clot attachments. A contrast solution is injected into a foot vein through a catheter, movement of the solution is through the vein is observed with a fluoroscope while x-rays are taken. This process takes about 3- to 45 minutes.
Radionuclide Venography- A radioactive isotope is injected if a patient has reactions to contrast solutions
Doppler Ultrasonography- This is the preferred procedure. This method uses waves to measure blood flow through leg veins and arteries. A blood pressure cuff is wrapped around the patient’s ankle and a transducer with gel on it is placed over pulse points of the foot and lower leg. High frequency sounds bounce off the soft tissue and the echoes are converted into images on a monitor. This process takes 30-45 minutes.
Impedance plethysmography- This records changes in blood volume and vessel resistance. A blood pressure cuff is wrapped around the leg above the knee, four electrodes are placed near the knee and ankle and the cuff is inflated. How efficiently the veins return to normal is measured. This technique takes 15 minutes.
Risk Factors of DVT
A combination of notes from Griffith’s Five Minute Clinical Consult, BUPA’s website and www.economyclasssyndrome.com catalogs the risk factors:
DVT’s are rare in young people , usually occurring in people aged over 40
Obese and tall people are at greater risk
Those with a history of leg clots
Pregnancy and childbirth- Related to hormone changes that make blood clot more easily and because the fetus puts extra pressure on the veins of the pelvis. There is also risk of injury to veins during delivery or a Caesarian. The risk is at its highest after childbirth
Women who take contraceptive pills that contain estrogen. Most modern pills contain a low dose, which increases the risk by an amount that is acceptable for most women. Estrogen lowers antithrombin levels
Women who take hormone replacement therapy
Men/ women with varicose veins and other venous complications
Those who have thrombophilia ( the opposite of Hemophilia) have blood that coagulates rapidly
People whose family has a history of DVT
Paralyzed or immobile people
Cancer patients- Because the cancer, its treatment and the presence of additional risk factors can result in hypercoagulable state
People who have major surgery or a broken leg because they are unable to move the leg and encourage blood flow
Travelers- A French study has shown that journeys more than five hours long by car, plane or train increase the risk fourfold. This is particular with air-travel because of the combination of inactivity and dehydration, which makes blood more sticky.
Prevention of DVT
The Oxford Textbook of Medicine and BBC News’ Medical Notes cites the general preventative advice as follows:
Exercise the legs regularly
Maintain a weight that is appropriate for your height
Avoid sitting and lying in bed for long periods without moving the legs
Women, especially those over 35, should consider the risk involved with taking the pill
Take aspirin which cuts clot formation and thins blood
BUPA’s website also offers prevention advice for travelers:
Exercise the legs at once every hour during long-distance travel. This includes taking regular breaks if driving or walking up and down the aisle of a train, coach or plane
Don’t take sleeping pills
Wear loose-fitting clothes
Keep the legs uncrossed
Keep hydrated, avoid alcohol to prevent hydrations
Treatment of DVT
According to BUPA’s website, treatment aims to prevent:
The clot from becoming larger
The clot breaking loose and traveling to the lungs
New clots from forming
Medicines are the first form of treatment. The most common treatment is anticoagulant ( blood thinning) medicine, which reduce the blood’s tendency to clot. These are taken for 3 to 6 months. Regular blood tests are needed to check the levels of the drug in the blood. The two main anticoagulants are heparin, given through a vein as a ‘drip’ or injected just under the skin twice a day and warfarin (taken as tablets). Clot dissolving drugs called thrombolytics are used to dissolve a DVT, but are only used when a life or limb is threatened because they carry a high risk of bleeding. Pharmaceutical prophylaxis can be used if one has serious risk factors or must sleep during a flight. This is a shot to be taken in stomach fat.
Graduated Compression Stockings are used to relieve pain and to prevent Post-thrombotic Syndrome. Doctors recommend wearing graduated compression stockings( also called TED or thrombo-embolic deterrent stockings) which are tighter at the foot than higher up the leg. They may have to be worn for several months or more.
Most people with DVT are advised to place a cushion under their feet while resting or sleeping so that the feet are raised higher than the hips. This helps reduce pressure in the veins of the calves.
Painkillers and heat applied to the area also help provide relief of DVT symptoms.
Risktutor’s Online Newsletter Library gives the following statistics as of April 2003:
Deep vein thrombosis occurs in approximately 2 million Americans each year
Each year 600,000 of these patients develop pulmonary embolism
Each year as many as 200,000 patients die of pulmonary embolism
More people die each year from pulmonary embolism than do from breast cancer
Women are affected more by pulmonary embolism more often than men
DVT recurs in 5-10% of patients the year after anticoagulant therapy is discontinued
DVT recurs in 30% of patients eight years after anticoagulant therapy is discontinued
I’m sure few of you ever knew about DVT and its fatal complication, pulmonary embolism. I only became aware of it because I lost my father to it. Now that you know the risk factors, and how we are easily susceptible to getting it, I suggest we all try to prevent the conditions which encourage DVT. Although young people are not at great risk, many other common influences can cause a DVT, which is something that we as youth must take seriously. DVT is a silent killer. Don’t allow it to silence you!
Weatherall, D.J., Ledingham, J.G.G., Warrell, D.A. (Eds). (1996). Oxford Textbook of Medicine. (Vol. 3) New York. Oxford University Press.
Dambro, Mark. R. (Ed). (2002). Griffith’s Five Minute Clinical Consult. Pennsylvania. Lippincott Williams and Williams.
Izenberg, Neil. (Ed). (2000). Human Diseases and Conditions. (Vol . 1) New York. Charles Scribner’s Sons.
Prophylaxis. Retrieved September 22, 2003, from
Economy Class Syndrome. Retrieved September 17, 2003, from
Deep Vein Thrombosis. Retrieved September 22, 2003, from
(2003, June). Deep Vein Thrombosis. Retrieved September 10, 2003 from
About Deep Vein Thrombosis (DVT) & Cancer. Retrieved September 10, 2003 from
Dangers of Flying. Retrieved September 10, 2003, from
(2003, April). Deep Vein Thrombosis (DVT) and Underwriting. Retrieved October 23, 2003, from http://www.risktutor.com/demo/apr_03.html
© rianna lee sing