What Is a Pulmonary Embolism?
A pulmonary embolism (PE) happens when a blood clot suddenly blocks an artery that supplies blood to your lungs.
Your blood goes from your heart to your lungs through your pulmonary artery. In the lungs, the blood is supplied with oxygen and then goes back to the heart, which pumps the oxygen-rich blood to the rest of your body.
When a blood clot gets caught in one of the arteries going from the heart to the lungs, you have a pulmonary embolism. The clot blocks the normal flow of blood.
This blockage can cause serious problems such as damage to your lungs and low oxygen levels in your blood. The lack of oxygen can harm other organs in your body, too. If the artery is clogged by a big clot or many smaller clots, it can cause a deadly pulmonary embolism.
Pulmonary embolisms usually travel to the lungs from a deep vein in the legs. Doctors call this deep vein thrombosis (DVT). These clots form when the blood can’t flow freely through the legs because your body is still for a long time, such as during a long flight or drive. It might also happen if you’re on bed rest after surgery or illness.
Stages of Pulmonary Embolism
Pulmonary embolisms are divided into three types.
Acute. When you have an acute PE, the symptoms come on suddenly.
Subacute. This type of PE happens slowly over a period — anywhere from 2 to 12 weeks. The symptoms are more subtle, which makes it more difficult to diagnose. Subacute PE carries a higher risk of death than acute PE.
Chronic. In chronic PE, you have symptoms that progressively get worse, including heart failure. This happens when a small blockage remains in your after you've had an acute PE.
Pulmonary Embolism Symptoms
Pulmonary embolism can cause a variety of symptoms. Some of the most common ones are:
- Shortness of breath, which may come on suddenly
- Chest pain, especially when you take a deep breath, lean over, or cough
- Fainting, which is caused by a sudden drop in your blood pressure (this is called syncope)
Other symptoms can include:
- A cough with bloody mucus
- Irregular or rapid heartbeat
- Sweating
- Dizziness
- Fever
- Clammy or discolored skin
- Leg pain or swelling, often in the calf area
- Wheezing
Pulmonary Embolism Diagnosis
It can be difficult to diagnose a pulmonary embolism, and that's especially true if you have another lung or heart problem already. Your doctor will start by asking questions about your medical history to get a clearer picture of what other conditions you might have.
Your doctor will do a physical exam and order tests. They can include:
Blood tests. Doctors will look for a few different clues in your blood. They include:
- High levels of D Dimera, a substance your body produces to fight clots.
- Unusual levels of carbon dioxide and oxygen
- Evidence that you have an inherited blood-clotting disorder
Chest X-rays. These might be used to rule out other conditions that could cause similar symptoms. But you can have a PE and still have a chest X-ray that looks normal.
Ultrasound. This uses sound waves to look for blood clots in your body. It's also calledduplex ultrasonography, a duplex scan, or compression ultrasonography.
CT pulmonary angiography. This is a type of X-ray that produces 3D images. The test sometimes uses a contrast solution, which you'll get by an IV in your arm or hand. That helps create clearer pictures. This is also called a CT pulmonary embolism study.
Ventilation/perfusion scan. If you need to avoid exposure to radiation from X-rays or the contrast substance used in CT pulmonary angiograms, your health care provider might order this test. It's also called a V/Q scan. You'll have a small amount of a radioactive substance, called a tracer, injected into a vein in your arm. As the tracer moves through your blood, doctors can monitor your blood flow (perfusion) and compare it to your airflow (ventilation).
Pulmonary angiogram. In this test, a thin tube is placed in an artery, usually through your groin. The tube -- called a catheter -- is threaded up into your pulmonary arteries. A special dye is injected into the tube, and X-rays are taken to show where the dye goes. This is one of the best tools to diagnose a pulmonary embolism. However, it carries some risks and requires a high level of skill, so it's not offered everywhere. The test can affect your heart's rhythm, and the dye can cause kidney problems.
MRI. This test uses magnetic fields and radio waves to create pictures of your body's organs. It's not the first choice of test to diagnose a PE, but if you're pregnant, it allows you to avoid radiation that could harm your baby. If you have a kidney condition, it allows you to avoid dyes that might cause problems.
Pulmonary Embolism Risk Factors
The risk factors are the same as those for DVT. Doctors refer to these as Virchow’s triad. They are:
- Not moving for a long time or having changes in normal blood flow. This often happens if you’ve been in the hospital or on bed rest for a long period. It also could happen during a long flight or vehicle ride.
- Blood that’s more likely to clot. Doctors call this hypercoagulability. It could be caused by medications, such as birth control pills. Smoking, cancer, recent surgery, COVID-19, or pregnancy also can put you at risk.
- Damage to a blood vessel wall. Injury to your lower leg can lead to this.
In rare cases, an artery in the lung can be blocked by something other than a clot, such as an air bubble or part of a tumor. If you break a big bone, fat from the bone marrow can sometimes come through the blood and cause blockage.
Other factors that up your risk for PE include:
- Obesity
- Diabetes
- Being older than 60
- You've given birth in the last 6 weeks
- You've had a catheter placed in a vein in your leg or arm
- You have a history of stroke, heart attack, or heart failure
Pulmonary Embolism Treatment
If you have a PE, your treatment might include medicine, surgery, or other procedures. The goal is to keep the clot from growing and to stop new clots from forming.
Medicine. A couple of different types of drugs may be part of your treatment plan. Blood thinners (anticoagulants) help keep your blood clot from getting bigger and can prevent new ones from forming. Heparin and warfarin are often used to treat PE. You may have anticoagulant drugs injected into a vein or under your skin. You also might receive a different drug that you take by mouth. If your situation is life-threatening, you might get a clot-busting drug through a vein. These drugs are called thrombolytics. They carry certain risks, which is why your health care provider may want to let your clot dissolve on its own.
Surgery. A surgeon might remove the blood clot from your lung using a thin tube inserted through blood vessels. This usually only happens in life-threatening situations.
Vein filter procedure. You might have a filter placed in your body's main vein, which moves blood from your legs to the right side of your heart. The filter catches blood clots before they can reach your lungs. This can be an option if you can't take blood thinners for some reason, or if those drugs aren't working to prevent clots.
Continuing care. You'll need to meet with your doctor regularly and stay on your medication to prevent another clot from forming.
Pulmonary Embolism Complications
The complications you might experience from a pulmonary embolism include:
- Heart attack
- Stroke
- Death of lung tissue (also called pulmonary infarction)
- Cyanosis, a lack of oxygen in your blood that can cause your skin to turn blue
- Pulmonary hypertension, high blood pressure in your lungs that puts a strain on your heart
- Shock, which keeps your vital organs from getting enough blood
A PE that's not diagnosed and treated promptly can be fatal.
Pulmonary Embolism in Pregnancy
Pulmonary embolism during labor or shortly afterward is one of the most serious pregnancy complications you can have. In developed countries, it's the No. 1 cause of death among those who've just given birth.
Among the things that put you at higher risk for PE during or after childbirth are:
- History of blood clots, either you or a family member
- History of varicose veins
- Weight (your risk goes up if your BMI is 30 or higher)
- Irritable bowel syndrome, which makes you more prone to blood clots
- Carrying twins or other multiples
- Having a C-section
Pulmonary Embolism Prevention
The best way to prevent a PE is to try to stop blood clots from forming deep in your veins. This can be challenging if you’ve been on bed rest after a surgery or illness, or if you just took a long flight.
If you’re at risk, here are a few things that may help lower your chances of getting these dangerous blood clots:
Blood thinners . These drugs, also called anticoagulants, keep your blood from forming clots. Your doctor may prescribe them to you while you’re in the hospital for surgery. They might also suggest that you keep taking them for some time after you go home.
Your doctor might also recommend blood thinners if you’ve been hospitalized after a stroke or heart attack, or if you have complications from cancer.
Compression stockings . These are long socks that squeeze your legs. The extra pressure helps blood move through your veins and leg muscles. Your doctor may recommend that you wear them for a while after surgery.
Exercise . Get out of bed and walk when you’re getting over a long stay in the hospital or an illness that’s kept you in bed for too long. It’ll keep the blood in your legs flowing so it doesn’t have a chance to pool.
Stretching during trips. If you’re on a long flight, try to walk around every few hours. If you can’t stand up, flex your ankles by pulling your toes toward you.
Here’s another stretch you can try to do while seated:
- Pull your leg up toward your chest with one hand.
- Hold the bottom of that leg with the other hand.
- Keep this pose for 15 seconds, and then try it with the other leg.
- Do this up to 10 times per hour.
If you’re driving a long distance, stop every hour and stretch your legs.
Also, be sure to drink extra fluids to help you stay hydrated.
Lifestyle changes. Other steps you can take include:
- Maintain a healthy weight.
- If you plan to take hormones, such as birth control or replacement therapy, talk to your doctor about your risk for blood clots.
- If you have other health issues, such as diabetes or heart failure, take your meds, watch what you eat, and talk to your doctor about any changes.
- Also talk to your doctor if you have a history of kidney disease , certain autoimmune diseases, or a family history of blood clots.
- If you smoke, quit.
Takeaways
A pulmonary embolism, or PE, is a blockage in the arteries that deliver blood to your lungs. It can happen when a blood clot forms in your leg (deep vein thrombosis) and travels through your body. Symptoms include being out of breath, chest pain, and passing out. Without quick treatment, this can be a life-threatening condition. Doctors may use blood thinners and clot-busting drugs to treat it. In some cases, you might need surgery to remove the clot, or a filter may be placed in your body's largest vein to keep clots from moving up from your legs.
Pulmonary Embolism FAQs
Can you recover fully from a pulmonary embolism?
Once you begin treatment, you should begin to feel better within a week. However, the clot itself can take months or even years to dissolve. How well you recover depends on several factors, including the size of the clot and your overall health.
What is the life expectancy of a person with a pulmonary embolism?
Without prompt treatment, about a third of people with PE die, often within the first few hours at the hospital. Among those who get the right diagnosis and treatment, about 8% die. Your overall health and the cause of your PE play a role in your long-term outlook. One study found that the 1- and 5-year survival rates were around 90%. The exception was among those whose PE was related to cancer; their survival rate was 60% at the 1-year mark and 39% at the 5-year mark.
