Health Encyclopedia:


Pulmonary Embolism

Your health care provider has told you that you have pulmonary embolism (PE).  A pulmonary embolism occurs when a blood clot forms in a vein (thrombus) and travels through the blood into the lungs (embolus).

This can cut off the flow of blood in the lungs, forcing the heart and lungs to work harder. This extra stress on the heart and lungs can cause them to fail. PE is a medical emergency and may cause death. 

A pulmonary embolus is most often from a blood clot that has formed in a deep vein of the leg. This is called deep vein thrombosis (DVT). Part of the clot breaks off and travels to the lungs.

Health care providers use the term venous thromboembolism (VTE) to describe these two conditions: deep vein thrombosis and pulmonary embolism. They use the term VTE because the two conditions are very closely related. And, because their prevention and treatment are also closely related. 

Outline of human torso showing heart, lungs, and major veins. Blood clot is in leg vein with arrow showing it traveling up vein to lung causing pulmonary embolism.
A pulmonary embolism occurs when a blood clot forms in a vein and is carried by the blood into the lungs.

How is pulmonary embolism diagnosed?

Your health care provider examines you and asks about your symptoms and medical history. You may also have one or more of the following:

  • Blood tests to check for blood clotting or other problems.

  • Imaging tests to look for clots in the veins or lung.

  • Electrocardiography (ECG or EKG) to test how well the heart is working.

How is pulmonary embolism treated?

  • Blood-thinning medications (anticoagulants). These medications thin the blood. They may be given as a pill, or as an injection through a tube into a vein (IV).  Blood thinners help prevent more blood clots from forming and prevent an existing clot from getting larger. Anticoagulants do not dissolve the blood clot, but help keep clots at a size that can be dissolved naturally by the body.

  • Thrombolysis.  This involves the use of medicine (thrombolytic) to dissolve a blood clot quickly. They may be used to dissolve a large clot that is causing significant problems in the lungs.  A catheter (thin tube) is used to deliver medication directly to the clot to dissolve it. Thrombolytic medications are typically reserved for life-threatening situations because of their risk for sudden bleeding.

  • Inferior vena cava (IVC) filter surgery. The IVS is the body’s largest vein. It carries blood to the heart from the body. A small filter placed in the IVC traps blood clots in the lower body and prevents them from traveling to the lungs. The filter is inserted into the vein through a catheter. The filter may be used if blood thinners cannot be taken or if they don't work. 

  • Pulmonary embolectomy. In severe cases, when thrombolysis cannot be used or is not successful, pulmonary embolectomy may be recommended. This is a procedure to remove a large blood clot. It can be done surgically or by using a catheter, depending on the situation.

What are the long-term concerns?

With treatment, blood clots are usually dissolved or removed. Some treatments can even help prevent future clots. But, having a PE can put you at risk for another life-threatening blood clot. So, you will likely need to take anticoagulants to help keep blood clots from forming again. You may need to take this medication for months or years.

You may also need to make lifestyle changes. This may include getting more active and eating healthier. You may need to wear compression stockings and and take breaks on long trips.



Get emergency help 

Call 911 or seek emergency help if you have symptoms of a pulmonary embolism, which may include:

  • Chest pain

  • Trouble breathing

  • Coughing up blood

  • Fainting

  • Dizziness

  • Rapid, pounding, or unusual heartbeat

  • Sweating more than usual

  • Unusual swelling or pain in your leg, arm, or other area (from a deep vein thrombosis)

Online Medical Reviewer: Holloway, Beth, RN, M.Ed.
Online Medical Reviewer: Petersen, Sheralee, MPAS, PA-C
Last Review Date: 3/31/2015
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