Deep-Vein Thrombosis (DVT) Symptoms
Not all DVTs cause noticeable symptoms, but the most common are swelling and redness in the affected leg, often associated with some pain in the same area. Severe chest pain or problems breathing may indicate a pulmonary embolus and should be evaluated immediately.
DVT of the leg or arm
- Discoloration or redness
Pulmonary Embolus (PE)
- Unexplained shortness of breath
- Chest pain or palpitations
- Anxiety and/or sweating
- Coughing up blood
Deep-Vein Thrombosis (DVT) Diagnosis
Although a number of tests have been evaluated over the years, only three have been shown to have special value for diagnosing DVT in symptomatic patients: venous ultrasonography, venography and impedance plethysmography (IPG).
- Venous Ultrasonography of the venous system is obtained with high-resolution equipment to produce two-dimensional images of reflected signals from an array of ultrasound sources, including the common femoral vein in the groin and the popliteal vein, which connects to the femoral vein. Gentle pressure is applied with the probe to determine whether the vein under examination is compressible. The most accurate ultrasonic criterion for diagnosing venous thrombosis is non-compressibility of the venous lumen (cavity) under gentle probe pressure.
- Venography is performed by injecting radiographic material into a superficial vein on the top of the foot. The contrast material mixes with the blood and flows through the leg. An X-ray image of the leg and pelvis will show the calf and thigh veins, which drain into the external iliac vein. A clot is diagnosed by the presence of an intraluminal filling defect, an abrupt cut-off of the contrast material on the x-ray.
- Impedance plethysmography (IPG) is performed by placing two sets of electrodes around the patient's calf and an oversized blood pressure cuff around the thigh. The electrodes sense a change in blood volume, which is recorded on a strip chart. Changes in venous filling are produced by inflating the thigh cuff to obstruct venous return and then reestablishing blood flow by deflating the cuff and assessing the time taken for venous volume in the calf to return to baseline. If a clot is present in the popliteal or more proximal veins, venous emptying is delayed.