A deep vein thrombosis, commonly called a "DVT", occurs when a blood clot develops in the large veins of the legs or pelvis. This is different from blood clots in the superficial veins, which is called phlebitis and varicose veins. A DVT can be life threatening if it breaks free and goes to the lungs. This is called a pulmonary embolism or "PE". Together, both disease states (DVT and PE) are called venous thromboembolism or "VTE". In the United States, the frequency of VTE is one to two million events and are responsible for fifty to three hundred thousand deaths per year.
About 50% of patients with DVT will present no symptoms. However, symptoms of DVT may include:
- Swelling of the leg or along a vein in the leg (on one side)
- Pain or tenderness in the leg, which you may feel only when standing or walking
- Increased warmth in the area of the leg that's swollen or in pain
- Red or discolored skin (pale or blue) on the leg
Almost all patients who have pulmonary embolism (PE) have symptoms, such as:
- Unexplained shortness of breath
- Fast breathing
- Fast heart rate
- Pain with deep breathing
- Coughing up blood
- Sudden collapse and death
- Feeling of apprehension
Any person that has signs and symptoms of a DVT or PE should seek immediate medical attention.
Since DVT and PE are considered different spectrums of the same disease (that is VTE), the risks are similar. Below is a list of risk factors for these diseases:
- Greater than 40 years of age
- Personal history of blood clots
- Family history of blood clots
- Active cancer
- Blood disorders
- Heart failure
- Recent surgery, trauma and joint replacement surgery
- Clotting disorders
- Medications (hormones, oral contraceptives, and breast cancer medication)
- Kidney disease
- Inflammatory bowel disease
The most common method of diagnosis is ultrasound. Ultrasound uses sound waves to create pictures of the vein and blood flow through the vessels in the affected leg. A blood test called a D-dimer may also be used. This test measures a substance in the blood that's released when a blood clot dissolves. If the test shows high levels of the substance, you may have a blood clot. If your test is normal and you have no risk factors, a blood clot is unlikely.
The most common method for diagnosing PE is a CT scan with contrast (dye) otherwise known as a CT angiography (specialized x-ray). For this test, contrast or dye is injected into a vein in your arm. The dye makes the blood vessels in your lungs and legs show up on x-ray images. You'll lie on a table and an x-ray tube will rotate around you. The tube will take pictures from many angles, which will then generate images for the doctor.
Another test that is sometimes used to diagnose a PE is a ventilation and perfusion scan. This test uses radioactive inhaled gas and intravenous injection to diagnose blood clots in the lung.
The treatment of PE and DVT involves thinning the blood with anticoagulants. In general, quick acting agents given intravenous or subcutaneous such as heparin, low molecular weight heparin, and synthetic heparin like drugs are used. These drugs are given short term and are often replaced by oral drugs such as warfarin or coumadin. An immediately acting intravenous or injected blood thinner must be administered right away to prevent worsening of the clot. The oral blood thinner, warfarin, takes about 5 days to become effective to prevent the development of a recurrent PE or DVT.
In severe cases, more aggressive therapy includes using blood thinners plus "clot buster" drugs such as TPA or catheter-based or surgical embolectomy to remove the PE. The duration of treatment with the oral blood thinner will vary from a 6 month minimum to lifelong, depending upon the circumstances of the PE and or DVT and other risk factors.