Blood Clots in Lungs: Before and After Pulmonary Embolism

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A pulmonary embolism (PE) is a blood clot that has broken off a blood vessel, traveled to the lungs, and blocks a lung artery. It affects approximately 900,000 people in the United States each year. It is a potentially life-threatening medical emergency.

This article will discuss how long it takes a blood clot to turn into a PE. It will also cover symptoms, treatments, and recovery.

healthcare provider speaking with patient

Luis Alvarez / Getty Images

Blood Clots in Lungs: Formation and Travel Time

A blood clot in the lung starts as a deep vein thrombosis (DVT). DVTs are blood clots that form in large veins, generally the arms or legs. When these clots break off from the blood vessel wall, they move through the circulatory system. Blood clots can get caught as they travel through the vessels; when they get to the lungs, it causes a PE.

A blood clot must break free from the blood vessel wall to travel through the circulatory system and to the lungs.

Pulmonary Embolism

An article in the journal Circulation from 2014 stated that the risk of a clot breaking off from the vessel wall and causing a PE is more common during the first few days through four weeks from clot formation.

Some people who have blood clots may not have symptoms. The blood clot may only cause symptoms once it reaches certain body areas like the lungs. Therefore, it is difficult to determine the time it takes for a blood clot to travel to the lungs.

Factors That Contribute to Lung Blood Clots

Anyone can get a PE. Certain factors increase a person's risk. These factors are:

Emergency Pulmonary Embolism (PE) Symptoms

A PE is a medical emergency. When a blood clot forms, it may not cause symptoms if it isn't causing a blockage.

The symptoms appear once the clot is large enough to block a vein or if it breaks off and moves to another area, creating a blockage.

PE symptoms can vary from very mild, with no symptoms at all, to incredibly severe. These symptoms may include:

  • Shortness of breath
  • Chest pain
  • Coughing up blood
  • Breathing fast
  • Increased heart rate
  • Sweating
  • Light-headedness
  • Feeling anxious or a sense of dread

Immediate Treatment for Blood Clots in Lungs

The treatment for a blood clot in the lungs depends on its severity and how it affects the organs in the body.

Someone who has a blood clot in the lungs and does not have difficulty breathing, has a normal blood pressure, and has a normal heart rate may only be treated with an intravenous (IV) anticoagulant or subcutaneous (SC) injections to stop further clotting. This will not break up a blood clot that is already formed.

Treatment for people with PE symptoms will be more aggressive. Its aim is to break up the blood clot in the lungs and prevent additional clots from forming. Treatments include both medications and procedures.

Medications for a blood clot in the lungs are:

  • Thrombolytics: Also called clot busters, this medication breaks up or dissolves existing blood clots. It is administered through an IV and given to people who have large blood clots causing serious symptoms. There is a risk of these medications causing significant bleeding and this risk is weighed against its benefits.
  • Anticoagulants: Also called blood thinners, these medications stop clots from forming. There is a risk of bleeding with anticoagulants. However, it is not as significant as with thrombolytics.

Procedures used to treat blood clots in the lungs are:

  • Catheter-assisted blood clot removal: During this procedure, a healthcare provider inserts a tube into the vein and advances it to reach the blood clot in the lung. Then, the clot can either be removed, or medication can be given to break up the clot.
  • Vena cava filter: In people who cannot take an anticoagulant, a filter is placed in the vena cava to stop blood clots from entering the lungs. This does not treat clots that are already in the lungs.

Learn more: Pulmonary Embolism Diagnosis: The 3-Step Process

Factors That Affect Survival and Ability to Recover

There are several factors that affect a person's survival after a PE. Overall health, comorbidities, and severity of the blood clot will all play a factor in a person's survival and ability to recover.

Another factor is blood clot size. The larger the size, the lower the chance of survival. Here are the types of blood clots in the lungs and their corresponding mortality rate:

  • Small pulmonary embolism: Up to 1%
  • Submassive pulmonary embolism: 5% to 25%
  • Massive pulmonary embolism: 18% to 65%

Healthcare providers use a scoring system to estimate survival. One scoring system used is the Pulmonary Embolism Severity Index (PESI). This system estimates a person's 30-day mortality rate by examining several variables. These variables would indicate that a person has a higher mortality rate:

  • Older age
  • Male gender
  • History of cancer
  • History of heart failure
  • History of lung disease
  • Low blood pressure
  • High heart rate
  • Low temperature
  • Altered mental status (confusion, disorientation, or lethargy)
  • Low oxygen saturation

Post–Pulmonary Embolism Considerations

After treatment for PE, you will need to take new medications and make lifestyle changes.

Anticoagulants will need to be taken for three months or longer, depending on the underlying cause of the blood clot.

When taking an anticoagulant, you will need to avoid foods high in vitamin K, alcohol, and aspirin. You should also avoid activities that could cause an injury and increase your chances of bleeding.

After a pulmonary embolism, a small percentage of people will develop scar-like tissue in the arteries. This will narrow or cause obstructions, leading to a type of pulmonary hypertension called chronic thromboembolic pulmonary hypertension (CTEPH).

Long-Term Monitoring After PE

Pulmonary embolisms often recur. Ensuring a long-term monitoring plan is in place to prevent recurrence is crucial. Be sure to attend all follow-up healthcare appointments and tests.

To prevent another DVT, which could lead to a PE, adopt these lifestyle changes:

  • Avoid smoking.
  • Exercise regularly.
  • Eat healthily.
  • Wear compression stockings, excet in a leg where there is a known blood clot (DVT).
  • Move around on long trips or flights.


PEs are a serious medical condition. When identified and treated promptly, outcomes are typically positive. Recovery may include anticoagulants and lifestyle modifications to prevent additional clot development. Contact a healthcare provider to clarify any questions surrounding clot management and life after a PE.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Patty Weasler

By Patty Weasler, RN, BSN
Weasler is a Wisconsin-based registered nurse with over a decade of experience in pediatric critical care.