Medical News Today
Written by Rhona Lewis
A pulmonary embolism occurs when a blood clot blocks one of the arteries in the lungs. A pulmonary embolism can happen after surgery if a blood clot forms inside one of the veins in the body and travels to the lungs.
Although most people recover with treatment, a pulmonary embolism can sometimes be fatal.
In this article, we look at how often pulmonary embolisms occur after surgery and when they can develop. We also discuss the symptoms, diagnosis, treatment, and prevention.
After surgery, there is a risk that a blood clot may form in the veins. This risk is due to the period of physical inactivity during and after the procedure.
Long periods of physical inactivity can mean that the blood does not circulate as well as it should. When blood pools, clots can form. The risk is particularly high following major surgery on the abdomen, pelvis, or legs.
The risk of pulmonary embolism varies among individuals, depending in part on their other risk factors.
In general, pulmonary embolism is the third most common cause of cardiovascular death worldwide, after stroke and heart attack. According to the American Lung Association, pulmonary embolism affects about 1 in 1,000 people in the United States every year.
However, with quick treatment, most people recover.
Experts generally consider the risk of developing a pulmonary embolism after surgery to be highest during the first 5 weeks after surgery. A 2019 study found that the risk was highest between 1 and 6 weeks after surgery.
The study included more than 60,000 middle-aged adults from a French patient database. For several types of surgery, the risk of pulmonary embolism remained elevated for 12 weeks in total. After 18 weeks, the researchers found no significant risk.
The symptoms of a pulmonary embolism can vary depending on the size of the clot. They can include:
- shortness of breath
- rapid breathing
- chest pain that gets worse upon exertion or feels like a heart attack
- pain in the arm, shoulder, neck, or jaw
- pain, swelling, discoloration, or tenderness in the leg or arm
- a cough with bloody mucus
- dizziness or lightheadedness
- pale, clammy skin
- excessive sweating
Most people will experience some symptoms, but not everyone does initially.
Pulmonary embolisms can be life threatening. If someone experiences any of the symptoms of a pulmonary embolism, they should contact a doctor right away.
Doctors use three methods to diagnose a pulmonary embolism: medical history, a physical exam, and medical imaging or blood tests.
During a physical exam, a doctor will look for any swollen or discolored areas on the arms or legs. They will listen to the heart and lungs and take a blood pressure reading.
Doctors may order a D-dimer blood test. D-dimer is a substance present in the bloodstream when a blood clot dissolves. High levels can indicate a blood clot.
Imaging tests that a doctor may recommend include:
- a computed tomography pulmonary angiography (CTPA), which is the primary method of detecting a pulmonary embolism
- a pulmonary ventilation/perfusion (V/Q) scan, which uses X-ray scans to show the flow of air and blood in the lungs
- an ultrasound to measure blood flow
- an electrocardiogram, which records heart activity using electrodes that attach to the chest
Doctors may use an MRI of the legs or lungs for those who are pregnant or cannot tolerate the contrast dyes that some imaging techniques require.
Once a person receives a diagnosis of pulmonary embolism, they should start treatment straight away.
First-line treatments do not dissolve the existing clot. Instead, doctors monitor the clot to make sure that the body is breaking it down on its own and prescribe medications to prevent new clots from forming.
People may need to take these medications for long periods, usually for at least 3 months.
Treatment may involve:
- Anticoagulants: These drugs are the most common treatment for pulmonary embolism. They prevent new clots from forming by thinning the blood. Examples include warfarin (Coumadin), fondaparinux (Arixtra), heparin, and low-molecular-weight heparin, such as enoxaparin (Lovenox).
- Thrombolytics: If a pulmonary embolism causes severe symptoms, such as low blood pressure, a doctor may recommend thrombolytic medications, which can dissolve the clot. However, although these medications can break up the clot, they can also cause severe bleeding.
- Surgery: If the body does not dissolve a blood clot, doctors may remove it surgically by threading a catheter into the blood vessel to break it up.
Bed rest after surgery increases the risk of a pulmonary embolism, but there are also other risk factors. These include:
- Long trips: Sitting for many hours in a car or plane can slow the flow of blood in the legs and lead to the formation of clots.
- Body weight: Excess weight increases the risk of a pulmonary embolism, particularly in females who also have high blood pressure or smoke.
- Hormonal medication: Birth control pills and hormone replacement drugs that are high in estrogen can increase clotting factors in the blood.
- Heart disease: This term refers to various conditions that affect the heart, including heart failure, atrial fibrillation, and heart attack.
- Cancer: Some types of cancer, including pancreatic, ovarian, and lung cancer, make clotting more likely.
- Smoking: Tobacco smoke narrows and damages the lining of blood vessels, making clots more likely. Exposure to secondhand smoke can also have this effect.
- Pregnancy: Clots can form during pregnancy if the fetus presses on veins in the pelvis, as this slows blood flow in the legs.
- Genetics: Less commonly, people can have genetic conditions that affect how blood clots form, making a pulmonary embolism more likely.
Although rare, a pulmonary embolism can also develop if a blockage develops from air bubbles, tissue from a tumor, or fat from the marrow of a broken arm or leg.
After major surgery, it can be difficult to reduce the risk of pulmonary embolism, as people are often unable to move around. However, until a person recovers, there are ways to reduce the risk.
- Elevating the legs: When lying down, people can elevate their legs by placing books or other objects underneath the lower end of their mattress.
- Wearing compression stockings: Graduated compression stockings squeeze the legs, keeping blood from pooling in them. People can also try special sleeves or boots that apply pressure to the legs.
- Moving as soon as possible: When it is safe to do so, people can start with small movements, such as flexing and stretching the feet. This motion prevents blood from settling in the calves.
If someone is at high risk for a pulmonary embolism, a doctor may suggest taking anticoagulants following surgery as a preventive measure.
Alternatively, they may recommend inserting a filter into the inferior vena cava vein, which runs along the spinal column. This filter catches blood clots before they reach the lungs.
Before or after surgery, people can also reduce the risk of pulmonary embolism by making dietary and lifestyle changes, such as:
- stopping smoking
- reaching or maintaining a moderate weight
- eating a balanced diet for heart health
A pulmonary embolism occurs when a blood clot blocks an artery in the lungs. The risk of pulmonary embolism after surgery is highest for the first 1–6 weeks, particularly if a person cannot move around.
Takin anticoagulants, using compression devices, and gradually increasing movement can reduce the risk. Anyone who is concerned about the risk of pulmonary embolism after surgery can speak with a doctor.