Symptoms, Diagnosis, Prevention and Treatment of Venous Thromboembolism

Venous thromboembolism (VTE) includes two related conditions:

• Deep vein thrombosis (DVT), when a blood clot forms in a deep vein, usually in the leg or pelvis
• Pulmonary embolism (PE), when the clot breaks off and travels from the leg, pelvis or other parts of the lower body to the lungs

DVT and PE are potentially serious, life-threatening conditions that require medical attention right away.

What are the warning signs of VTE?

DVT mainly affects the deep veins in the lower leg, thigh or pelvis. It most often affects only one leg. The clot can block blood flow in the vein and cause:

• Pain or tenderness in the leg, often in the thigh or calf
• Swelling in the leg (edema)
• Skin that feels warm
• Red or discolored skin

A PE can be life-threatening and, in some cases, fatal. A PE occurs when part of a clot, usually from a deep vein in the leg or pelvis, travels to the lungs and blocks blood flow in the pulmonary arteries. This can cause:

• Sudden unexplained shortness of breath at rest or with exertion
• Fast, shallow breathing
• Chest pain that may worsen with deep breathing or coughing
• Fast or irregular heart rate
• Light-headedness, dizziness or fainting
• Coughing, sometimes with blood-streaked mucus
• Low blood pressure
• Low oxygen levels in the blood
• Feelings of anxiety or sense of impending doom

If you notice symptoms like these, especially if they appear suddenly, seek medical care right away.

How is VTE diagnosed?

A health care professional will diagnose VTE based on your medical history, physical exam, blood work and imaging tests. Blood work may include a test called D-dimer, which detects signs of recent clot formation and breakdown.

For DVT: Ultrasound of the leg is most often used.

For PE: Computed tomography pulmonary angiogram (CTPA) is most often used. Sometimes a ventilation-perfusion (V/Q) lung scan is used if CTPA is unavailable or not safe for the patient, such as in those with kidney problems or a contrast dye allergy. A V/Q scan evaluates airflow and blood flow in the lungs using small amounts of radioactive tracer.

How can VTE be prevented?

Many blood clots can be prevented, especially when risk factors are noticed early. If you’re being admitted to the hospital or planning surgery, you can ask for a risk assessment for VTE. Learn the warning signs of a dangerous blood clot and speak up if anything concerns you.

Health care professionals determine risk by looking at a patient’s age, weight, medical history, medications and lifestyle factors.

Those at risk might:

• Take anticoagulant (anti-clotting) medications
• Use compression stockings or compression devices
• Move as soon as it’s safe after surgery or illness

After surgery or hospitalization

• Stay active as advised. Begin moving as soon as it is safe or as encouraged by your health care professional.
• Consider compression. Graduated compression stockings or intermittent pneumatic compression devices may be helpful if recommended by your health care team.
• Take medications as prescribed. If you have a high risk of a blood clot and a low risk of bleeding, your health care professional may prescribe an anticoagulant to prevent clots.

Traveling and blood clots

Long periods of immobility, such as during travel, can slow blood flow in the legs. Simple habits can help lower risk:

• Perform simple exercises. Flex and extend the ankles and knees and contract the calf muscles at regular intervals.
• Walk around. Get up and walk while traveling every one to two hours.
• Consider compression. Wear compression socks during your travel.
• Change positions while seated and avoid crossing your legs.
• Avoid alcohol and hydrate with water.

How is VTE treated?

Treatment usually includes anticoagulant medication to keep blood clots from continuing to form. It some cases, thrombolytic medications can be used to dissolve clots. Options include:

• Anticoagulants are the main treatment for most patients. Some common anticoagulants are:
  • Injectable medications, including heparin or low-molecular-weight heparin
  • DOACs (direct oral anticoagulants), oral medications such as apixaban, dabigatran, rivaroxaban and edoxaban
  • Warfarin, an oral anticoagulant that requires regular blood tests to monitor dosing

These medications are used for several months. If the VTE occurred after a surgery, trauma, pregnancy, hospital stay or with the use of hormone treatments, treatment can last for a number of months. For patients without these factors, treatment may be for longer periods depending on individual risk factors.

• Thrombolytic therapy uses medications, such as a tissue plasminogen activator (tPA), to dissolve clots quickly. This can be given through an arm vein or by inserting a catheter directly into the blood clot. This type of therapy is generally used for people with PE who have low blood pressure or life-threatening symptoms, or for select patients with extensive, limb-threatening DVT.
• Surgical procedures may also be used in select cases. One option is a mechanical thrombectomy, a procedure for removing a large blood clot from the vein. Others include catheter-directed thrombolysis, delivery of clot-dissolving medication directly to the clot, or injecting thrombolytic therapy into the vein or lung artery. In rare cases, surgery may involve placing a filter in the body’s largest vein, the inferior vena cava, to prevent blood clots from traveling to the lungs.

Anticoagulants are the first line of treatment for most patients. Thrombolytic or surgery is used for select high-risk cases.