How can further pulmonary embolisms be prevented?

Pulmonary embolism can occur after surgery or a long period of immobility, like when someone has to stay in bed because they are ill. It can also be triggered by things like cancer, blood-clotting disorders or treatment with certain hormones.

Some risk factors greatly increase the risk of having another pulmonary embolism. Others only have a small effect. Another important aspect is whether the risk factor is permanent, like a blood-clotting disorder, or temporary, like having to stay in bed after surgery.

Sometimes doctors can't work out what caused the pulmonary embolism the first time. When that happens, the likelihood of having another pulmonary embolism is higher. So, as strange as it sounds, uncertainty about the cause is a significant risk factor for further pulmonary embolisms.

Anticoagulants are very effective at preventing further pulmonary embolisms. The preventive effect stops as soon as you stop taking them. But so does the risk of side effects, especially heavy bleeding. Whether anticoagulants have more advantages or disadvantages depends on the person’s individual situation.

Anticoagulants generally increase the risk of bleeding. Heavy bleeding like brain hemorrhages or internal bleeding can even be fatal. Heavy bleeding occurs in around 1 out of 100 people who take anticoagulants. The risk increases with age. Other risk factors for heavy bleeding include:

• Blood-clotting disorder with a low platelet count (thrombocytopenia)
• Use of antiplatelets like acetylsalicylic acid (the drug in medicines like Aspirin) or non-steroidal anti-inflammatory drugs (NSAIDs)
• Previous bleeding
• Anemia
• Cancer
• Previous stroke
• Chronic kidney or liver disease
• Regular high alcohol consumption

The risk of bleeding can change over time – for instance, if new illnesses or poor kidney function develop due to aging. So a doctor will regularly assess the risk of bleeding. The dosage can then be adjusted as needed, or the preventive treatment can be stopped if no longer necessary. There are also various things you can do yourself to reduce the risk of bleeding and to detect bleeding early on.

Preventive treatment using anticoagulants isn't suitable for everyone who has an increased risk of developing another pulmonary embolism. Whether or not it’s the right choice for you depends on your

• risk of having another pulmonary embolism: The higher the estimated risk, the more the anticoagulants can help.
• risk of heavy bleeding as a side effect: The disadvantages of anticoagulants are particularly significant for people who are prone to bleeding anyway due to certain illnesses or medications.

When doctors rate the risk of further pulmonary embolisms as high, preventive treatment often has more pros than cons. Most people with a severe and permanent risk factor, like antiphospholipid syndrome, take anticoagulants permanently. Preventive treatment is also often recommended for people who have had a pulmonary embolism several times.

Preventive treatment is usually not needed if the risk of further pulmonary embolisms is considered to be low. This is especially true if the first embolism was caused by major surgery or a major injury that has since healed.

If the risk of further pulmonary embolisms is moderate, it’s often more difficult to decide whether preventive treatment is the right way to go. The line between the advantages and disadvantages is more blurred.

The doctor will help you make the right decision for you. This online decision aid may help if there are a lot of things to take into account or if you first want to figure out what your personal preferences are.