Pulmonary Embolism
Quick Facts
- A pulmonary embolism (PE) happens when a blood clot blocks one or more pulmonary arteries in the lungs. This reduces or stops blood flow to part or all of the lungs.
- An acute PE is a sudden blockage of the lung arteries by a blood clot.
- A PE can be fatal. Seek medical help right away if you think you have symptoms.
- Treatment for a PE can include medication or surgery.
What is a pulmonary embolism?
A pulmonary embolism (PE) occurs when a blood clot that forms in a deep vein becomes dislodged and travels to the lungs. This reduces or stops some or all of the blood supply to the lungs. Blood clots starting in the thigh are more likely to break off and travel to the lungs than blood clots in the lower leg or other parts of the body.
An acute PE is a sudden blockage of the lung arteries by a blood clot.
If you have a PE, your health care professional will assess your risk category based on how the clot is affecting your heart and lungs. This helps guide treatment and care decisions.
What are the warning signs of pulmonary embolism?
Pulmonary embolism can be life-threatening and, in some cases, fatal. A PE can cause symptoms such as:
- Chest pain that may worsen with deep breathing or coughing
- Sudden or unexplained shortness of breath at rest or with exertion
- Cough, sometimes with blood-streaked mucus
- Light-headedness, dizziness or fainting
- Signs of shock, such as confusion, cold or clammy skin or severe weakness
- Fast or irregular heart rate
- Low blood pressure
- Fast, shallow breathing
- Low oxygen levels in the blood
Get medical help right away if you think you might have symptoms of a PE.
What causes a pulmonary embolism?
A PE can be linked to a range of health conditions or life situations that make blood clots more likely. These may include:
- Conditions that increase the tendency for blood to clot (thrombophilia)
- Active cancer
- Some chronic conditions, including kidney disease, inflammatory bowel disease and autoimmune disease
- Recent surgery, especially major or orthopedic surgery
- Major trauma
- Prolonged lack of movement, such as bed rest or long periods of sitting or inactivity
- Congestive heart failure or chronic lung disease
- Serious infections, such as pneumonia, urinary tract infection or HIV
- Obesity
- Pregnancy
Understanding these risk factors can help you and your care team have more informed conversations about prevention and follow-up care.
What are the complications of pulmonary embolism?
The effects of a PE can vary widely from person to person. Some people may have no noticeable symptoms. In other cases, a PE can cause serious complications, including:
- Right-sided heart failure
- Low blood pressure due to shock (cardiogenic or obstructive)
- Sudden cardiac arrest
If you think you have a PE, it is important to get medical help right away.
How is a pulmonary embolism diagnosed?
If symptoms suggest a PE, a health care professional will ask about how you’re feeling, your medical history, and any known risk factors. A physical exam is usually part of this evaluation.
A blood test called a D-dimer may help determine whether additional testing is needed. If imaging tests are recommended, they may include:
- A computed tomography pulmonary angiogram (CTPA) is the most commonly used imaging test for PE. It provides detailed pictures of the blood vessels in the lungs.
- A ventilation-perfusion (V/Q) lung scan may be used if CTPA is unavailable or not safe for the patient, such as in those with kidney problems or a contrast dye allergy.
What are the stages of a pulmonary embolism?
PEs are grouped into categories based on how severe they are and how much they affect the heart and lungs. These categories range from A (least severe) to E (most severe). Knowing the category helps guide treatment decisions.
|
Category A: |
This PE is often found by chance during imaging done for another reason. |
|
| Category B: Mild with noticeable symptoms |
Symptoms may include chest pain or shortness of breath, but overall risk remains low based on vital signs and test results. |
|
| Category C: Symptoms with higher risk |
Symptoms may appear suddenly and include sudden onset of dyspnea (difficulty breathing, chest pain, cough) or lightheadedness. Test results and vital signs show an elevated risk, so close monitoring is needed. | |
| Category D: Warning signs of serious heart and lung problems |
This level may include:
Treatment is needed right away. |
|
| Category E: Life-threatening with cardiopulmonary failure |
This most severe level may involve:
This requires immediate and often advanced treatment. |
How is a pulmonary embolism treated?
Most people with a PE are treated in the hospital, where a care team can monitor their condition closely. Some people with mild or symptom-free PEs may be able to recover without a hospital stay. The length of treatment and type of care depend on how severe the clot is and how the other organs are affected by it.
Medications
Treatment often includes blood-thinning medications, also called anticoagulants. These help keep existing clots from growing and lower the chance of new clots forming. In some cases, clot-dissolving medications (thrombolytics) are used to break up clots more quickly.
Anticoagulants (blood thinners) are the main treatment for most patients. Some common blood thinners used are:
- Heparin or low molecular weight heparin, often started in the hospital via an IV or injection
- DOACs (direct oral anticoagulants), oral tablets such as dabigatran, rivaroxaban, edoxaban and apixaban
- Warfarin, an oral blood thinner that requires regular blood tests to monitor dosing
Many people take blood thinners for three to six months. Some people with ongoing risk factors or recurrent PE may need treatment longer.
Blood thinners increase the risk of bleeding. Patients taking warfarin require regular blood tests (usually monthly) to ensure the dose is safe and effective.
Thrombolytic therapy uses medications, such as tissue plasminogen activator (tPA), to dissolve clots quickly. This is given through a vein in the arm or, in some cases, directly into the clot using a catheter. This type of therapy is generally used for people with PE who have low blood pressure or life-threatening symptoms.
Surgical procedures
In select cases, surgical procedures may also be used. A mechanical thrombectomy, a procedure that removes a large blood clot from the lung arteries, sometimes combined with use of clot-dissolving medications, may be performed. In rare cases, surgery may involve placing a filter in the body’s largest vein, the inferior vena cava, to prevent blood clots from reaching the lungs.
Blood thinners are the first line of treatment for most patients. Thrombolytic therapy or surgery is used for select high-risk cases.
How can I lower my risk of having another pulmonary embolism?
Having one PE can increase the chance of another. The following steps can help lower your risk of having another PE:
- Following treatment guidance from your health care professional
- Taking your medications as prescribed
- Practicing heart-healthy habits, including:
- Eating a heart-healthy diet
- Being more physically active
- Avoiding all tobacco products
- Getting enough healthy sleep
- Reaching and maintaining a healthy weight
- Keeping your blood pressure, cholesterol and blood sugar in healthy ranges
- Learning whether blood clots run in your family
- Understanding which health conditions or medications may raise your risk
View fact sheet: What Is a Pulmonary Embolism? (PDF) | Spanish (PDF)
