A particular health risk largely associated with frequent air travel is developing DVT or deep vein thrombosis. Even a two hour travel by road tends to increase the risk of developing DVT. The contributing factor is that DVT occurs most frequently among people who are immobilized. Long-hour travel or otherwise, the good news is DVT is preventable and treatable. Read further to assess your risks of DVT, check symptoms or warning signs of DVT, the treatment options and ways to prevent DVT.
What is DVT?
In simple terms, DVT or deep vein thrombosis is the formation of thrombus (blood clot) in one of the large/deep veins in the body, predominantly in the lower limbs (the calf or thigh area). DVT can also affect the deep veins of the arms, pelvis or abdomen.
While blood clots are a natural reaction of the body to contain excessive blood loss after an injury (cut or wound) and help the body in the natural healing process, the same cannot be said about blood clots related to DVT which happen most of the time for no apparent reason. The blood clot so formed blocks the blood flow. The body reacts; pressure builds up in the vein.
Complication of DVT can result in pulmonary embolism which happens when a fragment of a blood clot breaks loose from the wall of the vein and travels to the lungs thereby blocking a pulmonary artery or one of its branches. Pulmonary embolism can be fatal because blocking the blood flow to the lungs will result in heart failure. Fatal or not, the deciding factors are the size of the clot and the pulmonary artery that is blocked. The two conditions put together, DVT and PE are known as venous thromboembolism or VTE.
Causes of DVT
Most of the time, it is hard to relate DVT to a specific health condition. However, continuous studies on the subject show specific circumstances that increase the risk of developing DVT. Each of these slow down or change the flow of blood leading to formation of blood clots.
Inactivity: Next time during a long-haul air travel, remember to walk. Being inactive for long hours slows down the blood flow in the veins and clots can form. DVT develops when a vein in the leg is either partly or completely blocked by a blood clot. But if you walk around, the leg muscles squeeze the veins and let blood flowing back to the heart.
Also during air travel, there is a likelihood of passengers becoming dehydrated. This can make the blood thicker than usual and the possibility of clotting is high.
Surgery: While recuperating after a surgery related to the hip region, pelvis or knee, surgery related to cancer or any major surgery, especially orthopedic and neurosurgery, the person becomes less active. Prolonged bed rest does not help the calf muscles to contract and help blood circulate, which can cause blood clots to develop.
Pregnancy: Few risk factors are specifically related to women like pregnancy, hormone replacement therapy and birth control pills. About 1 in 1000 pregnant women develop DVT during pregnancy. The compression of a large tummy, blood and hormonal changes, increased pressure in the veins in the pelvis and legs make pregnant women vulnerable to DVT. The risk is high if the pregnant woman:
HRT: Hormone replacement therapy increases the risk of developing DVT, anywhere between 2-3 times. How HRT raises the risk of DVT is not yet clearly established. This doesn't necessarily discourage women to opt for HRT but women who have suffered previous thrombosis should weigh the pros and cons before taking HRT.
Birth control pills: Many studies have been conducted to establish if use of birth control pills increases the clotting ability of blood. The risk increases with larger doses of estrogen.
Medications: Certain medications increase the risk of blood clot. The risk increases manifold if the person is diagnosed with a cardiovascular disease or in the presence of other health conditions.
Chronic illness: Serious illness such as congestive heart failure, heart attack, stroke, paralysis, lung disease, inflammatory bowel disease increases the risk of DVT.
Blood group A or AB: Segment of people with group A or AB blood group has a greater risk of blood clotting.
Symptoms of DVT
Deep vein thrombosis can be symptomless. Yet, being aware of the likely symptoms makes it feasible to seek medical attention without delay. It's not necessary for all of these symptoms to occur. Many times it can be just one or all and often times the symptoms may mimic an infection of the leg.
There are instances when the first sign of DVT has been that of pulmonary embolism. As these are life-threatening, seek emergency medical attention.
Diagnosing Deep vein thrombosis
Symptomatic individuals should meet their physicians. As symptoms alone cannot be relied for accurate diagnosis, history of the patient, physical examination and test results are also required.
History: The individual may have to answer oral questions or fill in a questionnaire. The aim is to gain insight into the overall health of the individual, medicines being taken, if he/she has undergone any recent surgery or has suffered an injury, if treated for cancer etc.
Physical exam: To evaluate the possible blood clot, the health care provider would inspect the legs for swelling, bulging veins and/or discoloration of the skin.
To evaluate DVT and rule possibility of cellulitis or thrombophlebitis, certain diagnostic tests will be required.
Ultrasound: The Doppler ultrasound test is required to determine whether a clot exists, the exact location in the leg and the size of the clot. The test is helpful to make a comparison at a later date to see whether the clot has grown or resolved. The test is advantageous for diagnosing clots higher in the legs but may miss some clots in the calves. To confirm the diagnosis of DVT, a venogram might be recommended.
Other tests that may be required are magnetic resonance imaging (MRI), CT or computer tomography scanning to view pictures of the organs and tissues. Blood tests may be recommended to rule out predisposition to blood clots. In case of complex DVT, more tests such as lung ventilation perfusion scan may be required to understand if oxygen and blood are flowing to all areas of the lungs.
Venogram is useful to show clots below the knees. The procedure involves injecting a special dye into the vein. An x-ray helps detect the exact area.
Deep vein thrombosis treatment
Medicines, self-care to surgery, DVT treatment is comprehensive in nature. It is not restricted to stopping clot propagation, preventing a clot from breaking off and travelling to the lung or other organs as well as preventing the recurrence, DVT treatment encompasses the occurrence of pulmonary embolism and its development.
Anticoagulant medicines are blood thinner medicines. Warfarin, Heparin, low molecular weight heparin (LMWH), these anticoagulant medicines are prescribed by doctors to treat DVT. These medicines lengthen the time taken for the blood to clot. Also, anticoagulant medicines prevent further development or growth of a clot; anticoagulant medicines are highly effective against formation of new clots and containing the existing clots. Also, anticoagulant medicines enable the body to break down and reabsorb the existing clots.
Clot busting drugs
Anticoagulant medicines cannot dissolve a DVT but they can enable the body to break down and reabsorb the existing clots. Most doctors prescribe clot busting drugs only if it is required to speed up the process in severe cases where the clotting can be highly life-threatening.
Graduated compression stockings
Post thrombotic syndrome is characterized by pain and swelling, mostly likely to occur during the recovery process. Graduated compression stockings help maintain circulation in the leg veins while walking or exercising, and reduce leg swelling. Compression stockings are available in different strengths of pressure. The doctor would recommend the most appropriate one after considering certain basic elements.
DVT surgery - venous thrombectomy
Even after adequate non-surgical treatment, if the symptoms continue to bother, surgery would be recommended. Surgery is the option for rare cases of DVT where the clot is large and is disrupting a major blood vessel.
Self-care and DVT prevention
Simple things go a long way in preventing DVT.
Knowing well that the chances increase by remaining immobile while travelling, particularly on long haul flights, remember to stay hydrated, perform simple leg exercise like flexing the ankles, raising and lowering the heels, and take occasional short walks during a refueling stop over etc. Talk to your doctor and check about wearing compression stockings while travelling. Discuss with health care provider alternatives to using birth control pills or hormone replacement therapy.