What Is a Pulmonary Embolism?

A pulmonary embolism (PE) is a blood clot that develops in a blood vessel elsewhere in the body (most commonly from the leg), travels to an artery in the lung, and forms an occlusion (blockage) of the artery.

A blood clot (thrombus) that forms in a blood vessel in one area of the body, breaks off, and travels to another area of the body through the bloodstream is called an embolus. An embolus can lodge itself in a blood vessel, blocking the blood supply to a particular organ. This blockage of a blood vessel by an embolus is called an embolism.

An embolism to the lung may cause serious life-threatening consequences and, potentially, death. Most commonly, a PE is the result of a condition called deep vein thrombosis (blood clot in the deep veins of the leg).

  • It is estimated that each year more than 600,000 patients suffer a pulmonary embolism.
  • PE causes or contributes to up to 200,000 deaths annually in the United States.
  • One in every 100 patients who develop DVT die due to pulmonary embolism.
  • If pulmonary embolism can be diagnosed and appropriate therapy started, the mortality can be reduced from approximately 30% to less than 10%.

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