By Roman Politi, MD
Deep vein thrombosis, or DVT, can occur when a blood clot forms inside a vein, usually deep within the leg and less frequently within the arm. About half a million Americans every year get a thrombotic clot, and up to 100,000 die because of it. The danger is that part of the clot can break off and travel through the bloodstream and block blood flow. Clots that lodge in the lungs are called pulmonary embolism and can cause organ damage or death. Clots can also plug veins in the brain and cause a stroke.
DVT is a preventable, but underdiagnosed and serious, medical condition. Venous blood clots pose significant health risks, and patients having DVT symptoms should seek prompt medical attention. When diagnosis and treatment are delayed for more than four weeks, serious, irreversible vein damage can result.
What are the symptoms of DVT?
The most common symptoms are pain, swelling, redness or a discoloration of the affected limb, but deep vein thrombosis can occur without noticeable symptoms. While limbs are most commonly affected, DVT can occur in other parts of the body, although that is comparatively rare.
Patients may confuse DVT pain with a muscle cramp, but the conditions differ in several ways. A cramp will often occur in both legs or at least in more than one area, while DVT pain will most typically be concentrated in one leg. Muscle cramps will cause pain but not include redness or cause the skin in the affected area to feel hot, symptoms commonly occurring with DVT. While cramp pain can be ‘walked off,’ pain caused a blood clot is more likely to persist.
How is DVT diagnosed?
The most common test for diagnosing deep vein blood thrombosis is ultrasound, which can detect blood flow abnormalities in a vein. Magnetic resonance imaging, computed tomography and blood tests may also be used as diagnostics tools.
How is DVT treated?
Initial treatment for DVT typically involves anticoagulants that reduce the blood’s ability to clot and prevent the clot from enlarging. Symptoms usually improve within a few days after starting the treatment. A follow-up ultrasound test should be done after anticoagulant therapy begins to determine if the clot is shrinking as the body resorbs it. Most patients with DVT recover completely within several weeks to months without significant complications or long-term adverse effects.
When a clot doesn’t respond to anticoagulants, thrombolytics that quickly break up blood clots may be given through an IV line or a catheter placed directly into the clot. There are several catheter devices designed to remove the clot as the thrombolytic drug dissolves the blockage. Filters inserted into the Inferior Vena Cava may be used to prevent clots that break loose from the legs from travelling to the heart and lungs and becoming a Pulmonary Embolism. To help prevent swelling associated with DVT, compression stockings can be worn on the legs.
What factors increase the risk of DVT?
The risk of developing DVT increases after age 40. Patients who had a prior blood clot or have a family history of the condition face a higher risk for DVT. The condition can also develop without a person having any known risks factors.
Some other factors increasing the risk for DVT include:
- Damage to a vein’s inner lining caused by physical, chemical, surgery, inflammation and immune responses
- Sluggish blood flow due to inactivity from illness, traveling for a long time or limited mobility from injury such a broken leg placed in a cast. About half of all blood clots occur during or soon after a hospital stay or surgery
- Some cancer treatments
- Varicose veins
- Excess weight
- Pregnancy or have recently given birth
- Estrogen-based medicine for hormone replacement therapy or birth control
- Anatomic venous compression syndromes such as May Thurner Syndrome
How can the risk of developing DVT be reduced?
Not smoking and maintaining an appropriate weight are important ways to reduce your DVT risk.
Regular exercise lowers your risk of blood clots. If you have had surgery or have been on bed rest for other reasons, return to regular activity as soon as possible.
When you travel for more than four hours, avoid tight clothing and drink plenty of water. Get up and walk around at least every couple of hours. If you have to stay in your seat, stretch and move your legs. Try clenching and releasing your calves and thighs, or lifting and lowering your heels with your toes on the floor. If you have risk factors for DVT, your doctor may advise you to wear compression stockings while traveling or suggest that you take a blood-thinning medicine before traveling.
Dr. Roman Politi is an interventional radiologist on staff at Cayuga Medical Center. He is board certified by the American Board of Radiology with a Certificate of Added Qualification in Vascular and Interventional Radiology. He can be reached at (607) 274-4134.