Pulmonary Embolism

Basic Facts

When a blood clot travels from the veins in the limbs and blocks an artery in the lungs, it causes a condition known as a pulmonary embolism.
Prompt diagnosis and treatment of pulmonary embolism reduces the risk of death and severe complications, which include pulmonary hypertension (high blood pressure in the arteries of the lungs) and damage to the heart.
Most pulmonary emboli can be treated with drugs that either prevent clots from forming or dissolve clots. In severe, life-threatening cases, surgery or catheter-based procedures to remove the clot may be required.
It is believed that pulmonary embolism is the leading cause of death in hospitalized patients in the United States, far outpacing infection.

A pulmonary embolism is a blood clot that forms in a vein, travels throughout the circulatory system, and eventually lands in an artery in the lungs.


Common symptoms include:

  • Shortness of breath, which is the most common symptom;
  • Rapid breathing, often accompanied by anxiety and restlessness;
  • Chest pain, sometimes radiating into the shoulder, arm, neck, and jaw;
  • Coughing or spitting up blood;
  • Lightheadedness and fainting;
  • Bluish skin tone; and
  • Wheezing.


The type of clot that is most likely to cause significant health problems originates in a vein deep within the muscle. This type of clot is called a deep vein thrombosis. While most clots form in a vein of the leg or pelvis, some begin in the arm. When this occurs, the clot blocks the artery, causing a condition known as pulmonary embolism.

Risk factors include:

  • Family history;
  • Blood clotting disorders;
  • Major surgery;
  • Prolonged immobility;
  • Cancer;
  • Prior episode of embolism;
  • Obesity;
  • Heart conditions;
  • Smoking;
  • High blood pressure;
  • Use of birth control pills;
  • Hormone replacement therapy;
  • Age; and
  • Fractures of pelvis, hip, or leg.


To diagnose pulmonary embolism, a doctor may perform a variety of specific tests, including:

  • Chest x rays;
  • Electrocardiography (ECG);
  • D-dimer enzyme-linked immunosorbent assay (ELISA);
  • Lung scanning;
  • Spiral computed tomography (CT) scan;
  • Contrast pulmonary angiography;
  • Duplex venous ultrasonography; and
  • Leg venography.


The mainstay of treatment for pulmonary embolism is administration of the blood thinning drug heparin. This drug is given intravenously. In patients who have experienced a massive pulmonary embolism, or who have a pre-existing heart condition or other health problem that complicates the situation, more aggressive treatments may be used. These treatments may include:

  • Thrombolysis;
  • Pulmonary embolectomy; and
  • Vena cava filter insertion.

Once a pulmonary embolism has been effectively treated, patients are usually put on a preventative drug regimen. In addition, patients are given a blood-thinning drug called warfarin (Coumadin).

Patients with a known risk of pulmonary embolism can try lifestyle measures that can reduce the chances of getting a blood clot. These include compression stockings, which squeeze the leg and vein muscles and help prevent blood from pooling in the legs and potentially clotting, and intermittent pneumatic compression, which involves wearing a special cuff around the thigh that improves circulation in the legs.