Overview

Pulmonary embolism (PE) is a potentially serious condition that occurs when a blood clot blocks a blood vessel in the lungs. It most commonly develops when a clot forms in a deep vein, usually in the leg or pelvis, and travels through the bloodstream to the lungs.

The severity of a pulmonary embolism can vary. Some cases may cause relatively mild symptoms, while others can significantly affect blood flow through the lungs and place strain on the heart. Prompt medical assessment is therefore important when pulmonary embolism is suspected.

At the Supreme Vascular and Interventional Clinic, Dr. Manish Taneja provides specialist assessment for selected vascular conditions, including pulmonary embolism and potential interventional treatment where appropriate.

Pulmonary Embolism at a Glance

• What it is: A blood clot that blocks a blood vessel in the lungs.
• Where it usually comes from: Many pulmonary emboli originate from deep vein thrombosis (DVT) in the leg or pelvis.
• Common symptoms: Sudden shortness of breath, chest pain, rapid heartbeat and coughing; symptoms can vary depending on the size and location of the clot.
• How it is diagnosed: Assessment may include medical history, physical examination, blood tests and imaging such as CT pulmonary angiography.
• How it is treated: Treatment depends on the severity of the pulmonary embolism and may include anticoagulation, thrombolysis or, for selected patients, catheter-based clot removal such as mechanical embolectomy.

What Is Pulmonary Embolism?

A pulmonary embolism occurs when a blood clot travels through the bloodstream and becomes lodged in a blood vessel supplying the lungs.

The clot can restrict blood flow through the lungs and, depending on its size and location, may place strain on the heart. Pulmonary embolism can therefore range from a smaller clot that is managed with medication to a more serious blockage requiring urgent intervention.

Pulmonary embolism is part of a broader condition known as venous thromboembolism (VTE), which includes both DVT and pulmonary embolism.

Pulmonary Embolism and Deep Vein Thrombosis

Pulmonary embolism and deep vein thrombosis (DVT) are closely related conditions within venous thromboembolism.

A DVT occurs when a blood clot forms in a deep vein, commonly in the leg or pelvis. If part of the clot breaks away, it can travel through the bloodstream to the heart and then into the lungs, where it may become lodged in a pulmonary artery and cause a pulmonary embolism.

Not every pulmonary embolism is preceded by noticeable symptoms of DVT, so the absence of leg swelling or pain does not rule out PE.

What Causes Pulmonary Embolism?

Most pulmonary emboli occur when a blood clot forms in a deep vein and subsequently travels to the lungs.

Factors that can increase the risk of developing a blood clot include:

• Prolonged immobility or long periods of sitting
• Recent surgery or hospitalisation
• Previous DVT or pulmonary embolism
• Certain cancers and cancer treatments
• Pregnancy and the postpartum period
• Some hormone-based medications
• Certain inherited or acquired blood-clotting disorders
• Increasing age
• Other medical conditions that increase the risk of thrombosis

Less commonly, pulmonary embolism can result from other types of embolic material, such as fat or, in particular medical circumstances, tumour or air emboli.

Having a risk factor does not necessarily mean that a pulmonary embolism will occur, and some cases develop without an obvious trigger.

Symptoms of Pulmonary Embolism

Pulmonary embolism symptoms can develop suddenly and may vary depending on the size and location of the clot.

Common symptoms may include:

• Sudden shortness of breath
• Chest pain, particularly pain that may worsen with deep breathing
• Rapid or irregular heartbeat
• Cough, sometimes with blood
• Light-headedness or dizziness
• Unexplained anxiety or a feeling that something is seriously wrong
• Fainting in more severe cases

Some people may also experience symptoms associated with DVT, such as swelling, pain, tenderness or warmth in one leg.

Because these symptoms can overlap with other heart and lung conditions, they require appropriate medical assessment rather than self-diagnosis.

How Is Pulmonary Embolism Diagnosed?

Diagnosis begins with assessing symptoms, medical history and risk factors for blood clots.

Depending on the circumstances, assessment may include:

• Physical examination
• Blood tests, including D-dimer testing where appropriate
• CT pulmonary angiography
• Ultrasound examination of the legs to look for DVT
• Electrocardiogram (ECG)
• Echocardiography or other cardiac assessment in selected patients
• Other imaging or investigations when required

CT pulmonary angiography can be used to visualise the pulmonary arteries and identify a blockage, while ultrasound may help identify a DVT that could be the source of the embolism.

The appropriate tests depend on the individual's symptoms, clinical risk and overall condition.

How Serious Is a Pulmonary Embolism?

The seriousness of a pulmonary embolism depends on factors including the size and location of the clot, how much blood flow through the lungs is affected, and whether the heart is under strain.

Some pulmonary emboli can be managed with medication and monitoring. More serious cases may cause significant cardiovascular instability and require urgent treatment to restore or improve blood flow.

This means that treatment decisions are based not only on the presence of a clot but also on its effect on the heart, lungs and overall circulation.

Does Pulmonary Embolism Always Require Treatment?

A confirmed pulmonary embolism requires medical assessment and appropriate treatment.

However, the type and intensity of treatment vary. Many patients can be treated with anticoagulant medication, which helps prevent existing clots from growing and reduces the risk of new clots forming.

Patients with more severe pulmonary embolism, significant cardiovascular compromise or particular clinical characteristics may require additional treatment.

The appropriate approach depends on the individual's condition, risk factors and response to treatment.

Pulmonary Embolism Treatment Options

Treatment for pulmonary embolism depends on the severity of the clot, its effect on the heart and lungs, the patient's overall condition and the potential risks associated with each treatment.

Anticoagulation

Anticoagulant medication is commonly used to prevent existing clots from growing and reduce the risk of new clots forming while the body gradually breaks down the clot.

Thrombolysis

In selected patients with severe pulmonary embolism, thrombolytic medication may be used to dissolve blood clots more rapidly.

Because thrombolytic treatment can increase the risk of serious bleeding, it is not appropriate for every patient.

Catheter-Based Clot Removal

Selected patients with significant or high-risk pulmonary embolism may be considered for a minimally invasive catheter-based procedure to remove or reduce clot burden.

One approach is mechanical pulmonary embolectomy, in which a specialised catheter is used to access the pulmonary arteries and remove clot material. Depending on the technique and device used, clot material may be aspirated, fragmented or retrieved.

Mechanical embolectomy is not required for every pulmonary embolism. It may be considered when a patient has significant clot burden or cardiovascular effects, when thrombolytic treatment may not be suitable, or when the patient has not responded adequately to previous treatment.

Surgical Embolectomy

In selected severe cases, surgical removal of the pulmonary embolism may be considered, particularly when other treatment approaches are unsuitable or unsuccessful.

Treatment decisions should be made by the appropriate specialist team based on the individual patient's circumstances.

When May Catheter-Based Treatment Be Considered?

Anticoagulation is an important part of treatment for many patients with pulmonary embolism. However, some patients may require a more active approach to clot removal.

A catheter-based treatment such as mechanical embolectomy may be considered depending on factors including:

• The severity and extent of the pulmonary embolism
• The patient's blood pressure and cardiovascular stability
• Evidence of strain on the right side of the heart
• The amount and location of clot within the pulmonary arteries
• The risk of bleeding
• Whether thrombolytic medication is appropriate
• Whether the patient has responded adequately to previous treatment
• The patient's overall health and other medical conditions

Mechanical embolectomy is therefore a selected treatment for pulmonary embolism, rather than a treatment required for every patient.

The existing Supreme Vascular article provides more detailed information about mechanical embolectomy, including patient selection and the catheter-based procedure itself.

How Is the Right Treatment Chosen?

There is no single treatment approach that is appropriate for every pulmonary embolism.

Specialists consider factors such as:

• The size and location of the clot
• The effect of the clot on blood flow through the lungs
• Heart function and signs of cardiac strain
• Blood pressure and overall circulation
• Risk of bleeding
• Other medical conditions
• Previous or current anticoagulant treatment
• The patient's overall clinical stability

This assessment helps determine whether medication alone is appropriate or whether thrombolysis, catheter-based treatment or another intervention should be considered.

When Should I See a Specialist for Pulmonary Embolism?

Anyone with suspected pulmonary embolism requires prompt medical assessment, particularly when symptoms such as sudden shortness of breath or unexplained chest pain occur.

Patients who have already been diagnosed with pulmonary embolism may also require specialist assessment when the condition is severe, symptoms persist despite treatment, or there are concerns about the effectiveness or suitability of the current treatment approach.

A specialist can review the available imaging, clinical findings and treatment history to help determine the most appropriate next step.

Pulmonary Embolism in Singapore

Patients in Singapore who have been diagnosed with pulmonary embolism or require specialist assessment for a vascular condition can seek evaluation based on their symptoms, imaging and overall clinical condition. At the Supreme Vascular and Interventional Clinic, Dr. Manish Taneja provides specialist assessment for selected vascular conditions and can evaluate whether an interventional treatment approach may have a role where appropriate.

Assessment may include reviewing the patient's medical history, symptoms, previous treatment and relevant imaging before discussing the available treatment options. 

Frequently Asked Questions About Pulmonary Embolism