What Is a Pulmonary Embolism? | Blood Clot Awareness Month | Video 4

A pulmonary embolism, or PE, happens when a blood clot blocks an artery in the lungs. It often begins as a clot in a deep vein in the leg or pelvis, called deep vein thrombosis, or DVT. Part of that clot can break away, travel through the right side of the heart and lodge in the pulmonary arteries.

In this fourth video of my Blood Clot Awareness Month series, I explain why recognising PE matters. It can be life-threatening, and the right response to possible symptoms is prompt medical assessment.

Why can a clot in the lungs be dangerous?

The pulmonary arteries carry blood from the heart to the lungs, where it picks up oxygen. A clot can obstruct that circulation, interfere with oxygen transfer and put strain on the right side of the heart.

The effect varies. Some people remain relatively stable, while others develop low oxygen levels, low blood pressure or collapse. The severity depends on the effect on the circulation and heart, alongside the person's overall health. A description of symptoms alone cannot establish how serious a PE is.

What symptoms need emergency attention?

Possible symptoms of pulmonary embolism include:

• Sudden or unexplained breathlessness.

• Chest pain, which may be worse when breathing in.

• Coughing up blood.

• A rapid heartbeat, marked light-headedness or fainting.

These symptoms may have other causes, but suspected PE needs emergency assessment. If you have symptoms suggesting PE, call 995 in Singapore. Do not wait for a routine clinic appointment or for symptoms to become severe.

Some people also have a painful, swollen or warm leg from an underlying DVT; others have no obvious leg symptoms. The absence of leg swelling does not rule out a pulmonary embolism.

How are DVT and pulmonary embolism connected?

DVT and PE are two forms of venous thromboembolism, often shortened to VTE. A deep-vein clot may stay in place, extend, or release material that travels to the lungs.

Risk can increase after surgery, during prolonged immobility, with active cancer, in pregnancy or after childbirth, and with certain hormone medicines. A previous blood clot also matters. Sometimes no clear trigger is identified. Knowing the circumstances helps guide treatment and decisions about preventing another clot.

I explain the leg-vein condition in more detail on my deep vein thrombosis page.

For treatment of related leg-vein clots, read the DVT treatment guide.

How is pulmonary embolism diagnosed?

Assessment combines the symptoms, risk factors, examination and appropriate investigations. Depending on the clinical situation, these may include blood tests and imaging. CT pulmonary angiography is commonly used to look for clots in the pulmonary arteries; alternative imaging may be chosen when it is more appropriate.

Tests may also assess the effect on the heart and oxygen levels. This information helps the treating team decide the urgency, location and type of care needed. Not everyone requires the same tests or treatment pathway.

Does every pulmonary embolism need clot removal?

No. Anticoagulant medicines are the main treatment for many people with PE. Often called blood thinners, they reduce further clotting while the body's own processes gradually deal with the clot. They do not physically extract it.

In the video, I describe aspiration thrombectomy: a catheter-based procedure that can remove clot from the pulmonary arteries. This is an option for selected patients, particularly when PE is causing serious circulatory problems or when the balance of risks favours an intervention.

Other advanced treatments include clot-dissolving medication or surgical removal in particular circumstances. These approaches carry risks and require specialist assessment. A procedure is not automatically better than anticoagulation, and recovery time cannot be promised in advance.

What happens after the immediate treatment?

Follow-up matters. The team reviews medication, bleeding risk, the likely cause of the clot and how long treatment should continue. Persistent breathlessness or reduced exercise tolerance after PE should be discussed rather than assumed to be part of normal recovery.

The pulmonary embolism guide brings together warning signs, treatment and follow-up after a lung blood clot.

For a non-emergency discussion about DVT, clot risk or vascular follow-up in Singapore, you can contact my clinic at Mount Elizabeth Novena Specialist Centre, #09-22, 38 Irrawaddy Road, Singapore 329563. New symptoms suggesting PE require emergency assessment first.

This article provides general education and does not replace an individual medical assessment.

What is a Blood Clot? | Singapore Vascular Surgeon

A blood clot is a mass formed when blood changes from a flowing liquid into a more solid structure. Clotting is normally protective: after an injury, it helps stop bleeding. The problem arises when a clot forms inside a blood vessel where it is not needed and obstructs the circulation.

In the first video of my Blood Clot Awareness Month series, I introduce this distinction. A clot is not simply “good” or “bad” in isolation. Its location, cause and effect on blood flow determine what it means for your health.

How does normal clotting protect us?

When a blood vessel is injured, platelets gather at the damaged area and help form a plug. Clotting proteins create a mesh of fibrin that supports it. Together, these processes help seal the injury while healing takes place.

The body also has mechanisms that limit clotting and break down clots when they are no longer needed. Health depends on keeping that balance: too little clotting can cause bleeding, while inappropriate clotting can block a vessel.

What is the difference between a clot in a vein and an artery?

Arteries carry blood away from the heart to supply the body. Veins return blood towards the heart. A clot can develop in either system, but the consequences and treatments differ.

A vein clot can obstruct blood returning from a limb and may travel to the lungs. An artery clot can interrupt the oxygen-rich blood reaching an organ or limb. The word “clot” therefore covers several conditions; it does not identify one diagnosis or one treatment.

My overview of vascular surgery explains how arterial and venous conditions fit within vascular care.

What are DVT, PE and VTE?

Deep vein thrombosis (DVT) is a clot in a deep vein, most often in the leg or pelvis. It may cause new one-sided swelling, pain, warmth or a change in skin colour, although some people have few obvious symptoms.

Pulmonary embolism (PE) occurs when a clot, commonly from a DVT, travels to and blocks an artery in the lungs. It can affect breathing and place strain on the heart.

Venous thromboembolism (VTE) is the collective term for DVT and PE. Understanding these terms helps make sense of medical discussions, but symptoms still need an assessment rather than a diagnosis based on an online description.

What is acute limb ischaemia?

A sudden blockage of an artery supplying a limb can cause acute limb ischaemia. This means the tissues are not receiving enough blood and oxygen. It is a vascular emergency.

A suddenly painful, cold, pale or numb foot or leg, particularly with weakness, requires immediate emergency assessment. Do not wait to see whether walking, massage or rest resolves it. It is different from the recurring walking discomfort described in peripheral arterial disease, although both involve the arterial circulation.

When should I seek help for a possible clot?

New, unexplained swelling or pain in one leg warrants urgent medical assessment for possible DVT and other causes. Sudden breathlessness, chest pain, coughing up blood or fainting could indicate PE and require emergency assessment.

For possible pulmonary embolism symptoms or a suddenly cold, painful, numb or weak limb, call 995 in Singapore. Early assessment allows the treating team to identify the problem and start appropriate care.

How are blood clots treated?

Treatment depends on where the clot is, how it is affecting the circulation and the person's overall health. Anticoagulants are commonly used for DVT and PE to reduce further clotting while the body works on the existing clot.

Some situations require clot-dissolving treatment, catheter-based removal or surgery. These are selected according to urgency, expected benefit and risk; they are not interchangeable treatments for every clot.

The guides to DVT treatment and pulmonary embolism explain these care pathways in more detail.

For a non-emergency discussion about DVT, previous clots or vascular symptoms, contact my clinic at Mount Elizabeth Novena Specialist Centre, #09-22, 38 Irrawaddy Road, Singapore 329563. Dr Andrew Choong's clinic can support assessment and follow-up, while acute emergency symptoms require immediate hospital care.

This article provides general education and does not replace an individual medical assessment.

World Thrombosis Day: How DVT and Pulmonary Embolism Can Be Fatal

A blood clot in a deep leg vein can become life-threatening if part of it travels to the lungs. That is the connection between deep vein thrombosis (DVT) and pulmonary embolism (PE), and it is the central message of my World Thrombosis Day video.

I am Dr Andrew Choong, a vascular surgeon in Singapore. On 13 October, World Thrombosis Day is an opportunity to explain what blood clots are, who may be at risk and which symptoms should prompt action. Recognising a possible clot early can make an important difference.

What is the difference between DVT, PE and VTE?

Deep vein thrombosis means a blood clot has formed within a deep vein, commonly in the leg. It can obstruct the return of blood towards the heart and cause swelling or discomfort. Some clots produce few obvious symptoms.

A pulmonary embolism happens when clot material travels through the circulation and blocks an artery in the lungs. The consequences range from breathlessness to a dangerous strain on the heart and sudden collapse. DVT and PE together are called venous thromboembolism, or VTE.

Thrombosis also occurs in arteries. The widely used World Thrombosis Day statistic that around one in four deaths worldwide involves a condition caused by thrombosis includes conditions such as heart attack and stroke; it does not mean that one in four people dies from a leg DVT.

Why can a blood clot develop?

Clot formation becomes more likely when blood flow slows, the vessel lining is affected or the blood has an increased tendency to clot. These factors can overlap. In my video, I highlight surgery, prolonged immobility and long journeys as situations in which people should be aware of their individual risk.

Hospital admission is especially important. Up to 60% of VTE cases are associated with a hospital stay, occurring during admission or within 90 days afterwards. That is why prevention planning may continue beyond the day a patient leaves hospital.

Your risk depends on the whole picture, including previous clots, current illness and treatment. A long flight does not affect everyone equally, and prevention should reflect your circumstances.

Which symptoms should I recognise?

A possible DVT needs prompt medical assessment, particularly when a change affects one leg. Warning signs may include:

• New swelling of the calf or whole leg.

• Pain or tenderness without a clear explanation.

• Warmth or a change in skin colour.

Sudden unexplained breathlessness, chest pain, fainting or collapse can indicate PE or another serious emergency. A racing heartbeat may accompany these symptoms. In Singapore, call 995 for an emergency ambulance when severe symptoms develop. Do not wait for a routine clinic appointment.

Symptoms alone cannot confirm or exclude a clot. Other conditions can look similar, and the absence of dramatic swelling does not make every situation safe.

How are DVT and pulmonary embolism treated?

Assessment starts with the symptoms and risk factors. Depending on the findings, clinicians use blood tests and appropriate imaging, such as ultrasound for suspected leg DVT. Testing is selected for the clinical situation.

Anticoagulant medication is central to treatment for many patients. It reduces the risk of clot extension and further clot formation while the body deals with the existing clot. The choice and duration require an individual assessment, including bleeding risk.

In selected cases, specialists may consider catheter-based treatment to remove or dissolve clot. My video describes the role of vascular surgeons in restoring blood flow, but a clot-removal procedure is not necessary or suitable for every DVT. The location, severity, timing and patient’s overall condition all matter.

What can I do after watching this video?

Know the warning signs, follow your hospital team’s prevention instructions and discuss personal clot risk before major surgery or prolonged immobility. If you develop new symptoms after discharge, mention your recent admission when seeking help.

For a non-emergency discussion about DVT and venous health, you can contact Andrew Choong Vascular Surgery. Current clinic location: Mount Elizabeth Novena Specialist Centre, #09-22, 38 Irrawaddy Road, Singapore 329563.