Pulmonary embolism (PE) is a common and potentially life threatening condition that doctors categorize as acute, subacute, or chronic. Deep vein thrombosis can increase a person’s risk of any type of PE.
This article discusses the definition and types of PE, the tests doctors use to diagnose it, and available treatments. It also looks into life expectancy for those with PE and how a person can reduce their risk.
A PE can be life threatening, especially if there are many blood clots or the blockage is large.
PE can lead to:
- permanent lung damage
- low blood oxygen
- organ damage from insufficient oxygen
Half of those who have PE do not experience any symptoms. However, symptoms can include:
There are three types of PE: acute, subacute, and chronic. Below is a deeper look into each of these types.
The most common symptoms include:
Risk factors for acute PE include gene mutations, protein S and protein C deficiency, and other factors such as prolonged periods of rest or inactivity, orthopedic surgery, obesity, pregnancy, and taking the contraceptive pill.
The NCBI further splits acute PE into two categories. The first — hemodynamically unstable — is a high risk form of PE that results in a significant change in blood pressure. This increases the chance of obstructive shock, which stops blood and oxygen from getting to the organs. It also has a higher mortality rate.
The second category is hemodynamically stable, an acute form of PE that can result in mild hypertension and present an intermediate risk. However, it is stable and may respond to fluid therapy.
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Symptoms can develop over 2–12 weeks. The most common symptoms can include:
- progressive dyspnea
- pleuritic chest pain
- coughing up blood
The authors of the 2020 study write that people with subacute PE have a higher risk of hypertension due to thromboembolism in comparison with those with acute PE.
This can cause chronic thromboembolic pulmonary hypertension (CTEPH). According to a
The most common cause of PE is DVT.
Conditions or events that can increase a person’s risk of DVT, and in turn, PE, include:
- Factor V Leiden mutation: This is a genetic mutation that increases a person’s risk of blood clots. Although the most common complications of Factor V Leiden mutation include DVT and PE, many people with this mutation will not develop a blood clot.
- Prothrombin gene mutation: An inherited genetic condition that
increasesa person’s risk of DVT.
- Protein C deficiency: A deficiency in protein C can increase a person’s risk of DVT. This condition can be mild or severe. And while some people will never develop blood clots, protein C deficiency can be life threatening in some infants. It can cause blockages in blood flow and body tissue death.
- Cancer: People with these conditions have the highest risk of developing a blood clot in their veins:
- Large bone fractures: The United Kingdom National Health Service (NHS) states that if a person fractures a large bone, such as the thigh bone, fat particles from inside the bone can release into the bloodstream. A fat embolism can go away on its own, but it can
causepotentially life threatening complications, such as organ dysfunction.
- Prolonged inactivity: Bed rest for
longer than 3 daysand traveling by bus, car, train, or plane for over 4 hours can increase a person’s risk of PE. This is because sitting for long periods can slow the blood flow in the veins in the legs. Individuals can reduce their risk of DVT while traveling by walking around every 2–3 hours, exercising their calf muscles while sitting down, stretching their legs, and wearing compression stockings.
- Pregnancy and childbirth: A person is at the highest risk of PE for 6 weeks after giving birth. During pregnancy, a person’s body changes so that it forms blood clots more easily,
lessening the riskof blood loss during labor and delivery. Additionally, the fetus can restrict blood flow to the lower legs because it can press on the blood vessels around the pelvis.
According to health experts, PE can be difficult to diagnose, as half of the people with the condition have no symptoms.
Diagnosing any type of PE includes reviewing a person’s medical history and carrying out a physical exam at a doctor’s office.
Running certain tests can effectively help a doctor or healthcare professional identify any blood clots and pinpoint the risk and severity of PE.
Some of these tests
- Arterial blood gas analysis (ABG): An ABG can help determine whether a person has PE. In uncommon cases, the analysis shows lower than expected levels of oxygen in the arteries, which could be a sign of shock and respiratory arrest.
- D-dimer: A common test that physicians use in combination with clinical assessment, probability, and other tests to determine whether an individual has PE. The D-dimer test looks for a small protein fragment that the body produces to break down blood clots. If a person has elevated D-dimer levels, this may suggest that their body is working to break down a blood clot.
- EKG: A standard EKG can help pinpoint tachycardia and irregular heartbeat patterns, such as straining in the right ventricular pathway of the heart and lung. These have links to PE, but not everyone with tachycardia or other irregularities will have PE, as many conditions can affect how the heart beats.
- CT pulmonary angiography: This is the diagnostic test of choice for people with a high risk of PE. It allows specialists to see the pulmonary arteries and visualize any pressure in the bloodstream.
- Ultrasound: An ultrasound scan of the lower extremities is the
most accuratenoninvasive test to diagnose DVT. It allows doctors to see a person’s veins and identify blood clots.
In large hospitals or cases involving a higher risk of PE in an individual, doctors have to follow test protocols by carrying out some of the above tests to rule out or confirm the condition.
However, smaller clinics may not have all the equipment to run various tests. As someone can stay asymptomatic for a long time and PE symptoms can vary, health departments have devised criteria for ruling out a PE.
The following criteria suggest that a person does not have a PE:
- they are younger than 50 years old
- their heart rate is lower than 100 beats per minute
- blood oxygen is higher than 94%
- no hemoptysis
- no estrogen use
- no prior PE or DVT
- no unilateral leg swelling
- no surgery or trauma with hospitalization in the past 4 weeks
Conversely, other criteria exist to determine the likelihood of PE. This can help doctors and specialists make recommendations for specific tests to confirm or rule out the condition. These depend on rules that doctors determine according to the individual’s medical history.
Examples of risk factors include:
- having active cancer
- being older than 65 years
- having had surgery or a fracture in the past month
- having lower-limb pain
- having a previous PE or DVT
A person should seek medical advice if they have any symptoms of a PE, as early treatment improves the outcome.
Treatment of PE can vary depending on the severity, hemodynamic stability, and type of PE a person has.
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- supplemental oxygen
- anticoagulant medication
- vitamin K antagonists to help reduce the action of vitamin K that can cause blood clotting
- thrombolysis, involving medication or a catheter to dissolve clots
- vena cava filters, which block the path of blood clots, stopping them from entering the lungs
These treatments can be similar for subacute cases. In fact, a
- 25% of people with PE have sudden death
- up to 30% die within 1 month of diagnosis
- up to 50% of individuals who had a DVT can have long-term complications
- up to 33% of people with DVT or PE have a recurrence within 10 years
It is extremely important for those at risk of PE to try and minimize their risk of developing or recurring PE.
A person can achieve this by:
- going for regular checkups for early diagnosis
- continuing the use of blood thinners after PE or DVT
- making lifestyle changes, such as eating a balanced diet and exercising regularly
- avoiding smoking, if applicable
- moving around regularly, especially after long periods of rest
Anyone can get a PE, which can be life threatening. Doctors split PE into three categories: acute, subacute, and chronic PE. The most common cause of PE is DVT, but genetic mutations and lifestyle factors, such as pregnancy, can also play a role in a person’s risk.
Someone with a PE may not develop any symptoms, but those who do may experience shortness of breath and coughing up blood.
There is a wide range of diagnostic tests, medicines, and procedures that can help identify and treat PE.
People with PE should regularly consult a doctor for checkups, continue their medication, and work to decrease their risk of complications by eating a balanced diet and exercising regularly.