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.

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.

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 DVT? Deep Vein Thrombosis Explained

Deep vein thrombosis, or DVT, is a blood clot in a deep vein. It most often affects the leg or pelvis, although it can also develop in an arm. Deep veins carry blood back towards the heart, so a clot can obstruct that return flow.

In the third instalment of my Blood Clot Awareness Month series, I explain why DVT deserves attention: it can cause immediate symptoms, sometimes lead to a pulmonary embolism, and leave longer-term problems in the affected leg. Recognising a possible clot is the first step towards getting it assessed.

What does a DVT feel or look like?

Possible signs include new swelling, pain or tenderness, warmth, and a change in skin colour, usually affecting one leg. The discomfort may involve the calf or thigh. An arm DVT can produce similar symptoms in the arm.

These signs do not prove that a clot is present. Muscle injuries, infections and other conditions can look similar, and some DVTs cause few or no obvious symptoms. Comparing one leg with the other can reveal a change, but a home examination cannot confirm or exclude DVT.

New, unexplained one-sided swelling or pain warrants urgent medical assessment. Do not wait for symptoms to become severe before seeking advice.

Why can a leg clot affect the lungs?

Part of a DVT can break off and travel through the bloodstream to the pulmonary arteries in the lungs. This is called a pulmonary embolism, or PE. It can interfere with oxygen exchange and strain the heart.

Sudden breathlessness, chest pain, coughing up blood or fainting need emergency assessment. For these possible pulmonary embolism symptoms, call 995 in Singapore; do not wait for symptoms to worsen. A routine vascular appointment is not the appropriate first step when PE is suspected.

DVT and PE are related conditions collectively called venous thromboembolism, or VTE. Not every DVT causes PE, but the possibility is one reason early diagnosis and treatment matter.

Can DVT threaten the leg itself?

Rarely, a very extensive DVT can severely obstruct the veins draining the leg. The leg may become dramatically swollen, very painful and discoloured. This severe condition, known as phlegmasia, can threaten the limb and requires emergency specialist care.

This is different from the more usual presentation of DVT, but it illustrates why a rapidly worsening, painful swollen leg should not be managed by waiting at home. Emergency assessment is particularly important if the limb becomes blue, cold or numb.

What is post-thrombotic syndrome?

After a DVT, residual obstruction or damage to the vein valves can make it harder for blood to return efficiently. Some people develop post-thrombotic syndrome, with persistent swelling, aching, heaviness or skin changes. In more severe cases, a venous ulcer can develop.

These problems can affect daily life even after the immediate clot has been treated. They do not happen to everyone. Follow-up allows ongoing symptoms to be assessed and a suitable management plan to be discussed.

Who is more likely to develop DVT?

Risk factors include recent surgery or hospitalisation, reduced mobility, a previous clot, active cancer, pregnancy and the period after childbirth. Certain hormone medicines and inherited clotting tendencies can also increase risk.

Long journeys can contribute through prolonged sitting, particularly when other risk factors are present. Sometimes a DVT develops without an obvious trigger. The clinical history helps determine both the likely cause and how best to reduce future risk.

How is DVT assessed and treated?

A clinician considers the symptoms, examination and risk factors. An ultrasound scan is commonly used to look for a clot in the deep veins; blood tests may form part of the assessment in selected circumstances.

Anticoagulant medicines are the main treatment for most DVTs. They help prevent the clot growing and reduce the chance of further clots while the body's natural processes work on the existing clot. Treatment duration depends on the individual situation.

Selected patients with extensive, severely symptomatic clots may be considered for catheter-based treatment. This is not necessary for every DVT. Decisions balance potential benefit against bleeding and procedural risks.

You can read more about DVT assessment and treatment or contact my Singapore clinic at Mount Elizabeth Novena Specialist Centre, #09-22, 38 Irrawaddy Road, Singapore 329563 for non-emergency advice and follow-up.

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

Why Do Blood Clots Form? DVT & PE Risk Explained

Why does a blood clot develop inside a vein when there has been no visible cut or injury? In this second video of my Blood Clot Awareness Month series, I explain three processes that help answer that question: slow blood flow, a greater tendency to clot, and injury to the vessel lining.

Together, these are known as Virchow's triad. One or more can contribute to deep vein thrombosis, or DVT. Understanding them helps explain why clot risk often changes around an operation, illness, pregnancy or a period of reduced mobility.

What happens when blood flow slows?

Movement helps blood return from the legs towards the heart. When the calf muscles contract, they support that return flow through the veins. Long periods without normal movement can allow blood to pool and increase the opportunity for a clot to form.

This can happen during bed rest, recovery from major surgery or a long journey. The level of risk varies: a person with a previous DVT, active cancer or several other risk factors may need a different prevention plan from someone without those factors.

Prolonged sitting is therefore part of the explanation, rather than a complete explanation on its own. An otherwise ordinary journey may become more relevant when it follows an operation or takes place during a period of illness.

When is blood more likely to clot?

Some conditions shift the body's clotting balance towards clot formation. Active cancer, pregnancy and the period after childbirth are examples. Certain hormone medicines and inherited clotting disorders can also contribute.

Previous DVT or pulmonary embolism is particularly relevant to a risk assessment. Family history can provide useful context, although it does not automatically mean someone has an inherited disorder or needs a blood test for one.

If you take a prescribed medicine that may affect clot risk, discuss it with your clinician. Stopping treatment without advice can create other problems; prevention decisions need to account for both the reason for the medicine and your individual circumstances.

How does injury to a vessel lining contribute?

The inside surface of a blood vessel normally helps blood flow smoothly. Surgery, trauma and inflammation can disturb that lining and activate the clotting response.

After an operation, several parts of the triad can overlap: there may be tissue or vessel injury, less movement than usual and a temporary change in clotting activity. That is why clot prevention is considered as part of surgical care, with measures chosen for the procedure and the patient.

A clot can also develop without a clearly identifiable trigger. The absence of recent travel or surgery does not rule out DVT.

What can help reduce the risk?

Prevention should match the situation. Useful discussions include when it is safe to mobilise after surgery, how to avoid prolonged immobility during travel, and whether a particular illness or previous clot calls for additional measures.

For some people, clinicians recommend anticoagulant medication or suitable compression as part of a prevention plan. These are not measures that everyone should start independently. Bleeding risk and other medical conditions affect what is appropriate.

Keeping normally hydrated is sensible general care, but drinking water is not a proven substitute for movement or an individual clot-prevention plan. If you have a previous clot or several risk factors, seek advice before a long journey or planned operation.

Which symptoms should not be ignored?

DVT may cause new swelling, pain, warmth or a colour change in one leg. These symptoms need urgent assessment because an examination alone cannot reliably establish the cause.

A clot can travel from a deep vein to the lungs and cause pulmonary embolism. Sudden breathlessness, chest pain, coughing up blood or fainting require emergency assessment. For these possible pulmonary embolism symptoms, call 995 in Singapore; do not wait for a routine appointment.

You can read more about deep vein thrombosis and its assessment. For a planned discussion of vascular symptoms or clot risk, contact my Singapore clinic at Mount Elizabeth Novena Specialist Centre, #09-22, 38 Irrawaddy Road, Singapore 329563.

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.

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.