World Thrombosis Day 2026: Blood-Clot Prevention Must Keep Pace With Hospital Care

Dr Andrew Choong's opinion article for World Thrombosis Day was published by Cambodianess on 7 October 2026. This post summarises the argument for patients in Singapore and across the region, and explains what it means for anyone going into hospital.

World Thrombosis Day falls on 13 October every year. It does not get the attention given to heart attack and stroke, yet the campaign behind it estimates that one in four deaths worldwide involves a blood clot of some kind. The clots that this day is really about are the quiet ones: a deep vein thrombosis in the leg that can break off and travel to the lungs as a pulmonary embolism. Together they are called venous thromboembolism, and most of them are preventable.

Why write about this for Cambodia?

Because the argument applies to every health system that is growing, and it is easiest to see where growth is fastest. Cambodia, like much of Southeast Asia, is bringing far more people into hospital than it did twenty years ago: more operations, more cancer treatment, far more births in facilities and a sharp rise in caesarean sections. Every one of those is good news. Each also adds to the number of people who are, for a few weeks, at raised risk of a clot. The article asks that prevention keep pace with that progress, and proposes four steps that any hospital system can take.

Are blood clots really a problem in Asian patients?

For a long time doctors in this region were taught that venous clots were a Western disease. A systematic review of Asian studies found rates at roughly 15 to 20 per cent of Western figures, but rising steadily, and the Asian venous thromboembolism guidelines link that rise to ageing populations, dietary change and more obesity and diabetes. Those trends are as true of Singapore as of Phnom Penh. The practical problem with the old belief is that it lingers: a swollen calf is put down to a strain, breathlessness to a chest infection, and the diagnosis is made late.

Where do most clots come from?

Hospital. Up to 60 per cent of venous clots occur during a hospital stay or within 90 days of leaving one. Surgery, serious injury, cancer and days spent in bed all slow the blood in the leg veins and make it more likely to clot. Pregnancy and the six weeks after delivery carry about four times the usual risk, and a pooled analysis found the risk after a caesarean section to be about four times that after a vaginal birth. A new mother with a swollen, painful leg or sudden breathlessness needs to be seen urgently, not reassured.

What does prevention involve?

Nothing new and nothing expensive. Getting patients moving early after an operation, compression devices on the legs during and after surgery, and low-dose blood-thinning injections for those at higher risk have all been standard practice for decades. The gap is in applying them consistently. The ENDORSE study looked at more than 68,000 patients in 358 hospitals across 32 countries: about half were at risk of a clot, and only about half of those received the recommended prevention. In some Asian countries surveyed the figure was close to zero.

What did the article propose?

Four steps, in order of effort. First, assess every adult on admission with a one-page checklist covering age, reason for admission, mobility, cancer, pregnancy and any previous clot, as the Asian guidelines already recommend. Second, include maternity care: every woman who has a caesarean section should be assessed for clot risk before she goes home and told which symptoms should bring her back. Third, keep a simple register of diagnosed clots at the major referral hospitals, so that the scale of the problem, and whether prevention is working, becomes visible. Fourth, teach the public the warning signs.

What are the warning signs?

In the leg: swelling, pain, warmth or redness, usually in one calf, which should be seen by a doctor the same day. In the lungs: sudden breathlessness, chest pain that is worse on breathing in, a racing heartbeat, or coughing up blood. These are emergencies. In Singapore, call 995.

What can you do yourself?

If you or a relative is admitted to hospital, ask two questions: what is my risk of a blood clot, and what is being done to reduce it? After an operation, get moving as soon as you are allowed. On long flights and long road journeys, walk when you can and flex your ankles when you cannot. Women starting a combined contraceptive pill or hormone therapy should mention any personal or family history of clots. None of this is complicated; it is a matter of knowing to ask.

“Cambodia has made great strides in bringing people into hospital for care. The next step is to make sure a preventable clot does not undo that care.”
Dr Andrew Choong, Cambodianess, 7 October 2026

Read the full article: As More Cambodians Are Treated in Hospital, Blood-Clot Prevention Must Keep Pace (Cambodianess, 7 October 2026). Other media features are collected on the In the Media page.

Preparing for a vascular review

If you have had a swollen or painful leg, a clot in the past, or persistent leg swelling after a clot, a vascular review can establish whether the deep veins are affected and what, if anything, needs to be done. The DVT page explains how a clot is assessed with duplex ultrasound, and the DVT treatment page covers blood thinners, clot removal and when each is considered. Patients travelling from Cambodia, Vietnam, Indonesia, Myanmar or the Philippines can read how to arrange a review on the international patients page. To make an appointment, use the contact page.

DVT Warning: Red, hot, swollen painful leg

A new swollen, painful or unusually warm leg, especially on one side, needs urgent medical assessment. It may be a deep vein thrombosis, or DVT: a blood clot in a vein deep inside the leg. Not everyone has every symptom, and you should not wait for a complete checklist before seeking help.

In this video, I explain why this combination matters, which situations can increase the risk of a clot and how an ultrasound scan helps investigate it. The message is straightforward: do not dismiss a sudden change as ordinary tiredness or your usual leg swelling.

What symptoms can a DVT cause?

Possible symptoms include:

• Swelling: commonly affecting one leg more than the other.

• Pain or tenderness: often in the calf or thigh, without an obvious explanation.

• Warmth: an affected area that feels hotter than usual.

• A change in skin colour: including redness or darker colouring, which may be less obvious on some skin tones.

Other conditions, such as infection, injury or inflammation, can produce similar symptoms. Some people with DVT have few or no obvious signs. This is why appearance alone cannot confirm or exclude a clot. Our DVT information page explains the condition in more detail.

Why can a clot in the leg affect the lungs?

A DVT can interfere with blood drainage from the leg. If part of the clot breaks away, it can travel through the circulation and lodge in the blood vessels of the lungs. This is called a pulmonary embolism (PE), which can be life-threatening.

Sudden breathlessness, chest pain, coughing blood, fainting or collapse require emergency assessment. These symptoms can occur even without obvious leg symptoms. In Singapore, call 995 for a life-threatening emergency. Do not wait for a clinic appointment or an online reply.

Who has a higher risk of DVT?

In the video, I highlight cancer, some blood conditions, long-haul travel, periods of immobility and major orthopaedic surgery. These situations may increase the tendency for blood to clot or reduce its movement through the leg veins.

Previous DVT, pregnancy and the period after childbirth, and some hormone treatments are also relevant. Several risks can occur together. However, DVT can happen without an obvious trigger, so the absence of a recent flight or operation is not a reason to ignore symptoms.

Long journeys by car, bus or train can also involve prolonged sitting. The concern is not unique to flying; limited movement and a person’s underlying risk both matter.

How is a suspected DVT assessed?

A clinician will ask about the symptoms, examine the leg and review your risk factors. A venous duplex ultrasound is a common first-line imaging test. It examines the deep veins and helps identify a clot and its location.

Depending on the clinical assessment, blood tests or further imaging may also be needed. If symptoms persist or change after an initial assessment, follow the advice given about reassessment. A scan result needs to be interpreted alongside the full clinical picture.

What happens if a DVT is confirmed?

Treatment commonly involves anticoagulant medicines, often called blood thinners. They help stop the clot extending and reduce the risk of further clots while the body deals with the existing clot. The medicine and duration depend on factors such as the clot’s location, cause and bleeding risk.

Some patients need additional specialist treatment. Follow-up also considers ongoing swelling or discomfort and whether there are underlying factors to address. A new suspected clot needs urgent care, rather than treatment based only on information in a video.

What can you do before a long journey?

Move your legs regularly and take opportunities to walk when safe. Keeping normally hydrated is sensible, but drinking water alone should not be regarded as protection against a travel-related clot.

If you have had a clot, recent surgery, cancer or another significant risk factor, discuss travel precautions with your clinician beforehand. Compression stockings or preventive medicines are appropriate for selected people and should be individually advised.

Related DVT Guides

Read more about DVT treatment in Singapore, pulmonary embolism and vascular duplex ultrasound. These guides support the urgent-care advice above; do not delay assessment for new symptoms.

DVT assessment in Singapore

Seek urgent medical care for new one-sided painful swelling. For non-emergency questions about previous DVT or ongoing venous care, contact Andrew Choong Vascular Surgery 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 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 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.

For more detail, read the guides to DVT treatment, venous duplex ultrasound and pulmonary embolism.

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.

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.

Blood Clot Removal for DVT | Modern Treatment Explained

Treatment for deep vein thrombosis, or DVT, can now include catheter-based techniques that remove clot from a vein. In this video, I explain how vascular treatment has developed, from anticoagulant medicines to clot-dissolving therapies and mechanical clot removal.

These developments add options for selected patients. They do not mean every DVT needs a procedure. The central question is whether removing the clot is likely to offer enough benefit for that person to justify the risks.

Why are anticoagulants still central to DVT treatment?

Anticoagulants, often called blood thinners, reduce the blood's ability to form further clot. They help prevent an existing DVT from growing and lower the risk of additional clots while the body's own processes gradually deal with it.

For most people with DVT, anticoagulation remains the main treatment. The medication, duration and follow-up plan depend on factors such as the clot's location, its likely cause, previous clotting events and bleeding risk.

A procedure does not automatically replace anticoagulation. Many patients still need medication afterwards, together with monitoring and advice about future clot risk.

What is catheter-based blood clot removal?

A catheter is a thin tube introduced into a blood vessel through a small access point. Guided by imaging, it can be positioned near or within a clot. The technique used depends on the clot, the anatomy and the clinical circumstances.

Catheter-directed thrombolysis delivers clot-dissolving medicine to the affected area. Mechanical thrombectomy uses a device to remove clot; aspiration thrombectomy uses suction. Sometimes approaches are combined, and a separate narrowing in the vein may need assessment.

These procedures differ from simply taking anticoagulant medication. They aim to clear clot more directly, but each approach has limitations and potential complications.

Who might benefit from a procedure for DVT?

Specialist assessment may consider an intervention for selected patients with a recent, extensive and severely symptomatic clot, particularly involving the major veins in the upper thigh and pelvis. Rarely, a DVT severely compromises drainage from the limb and becomes a limb-threatening emergency.

Important considerations include:

• Where the clot is and how long symptoms have been present.

• The severity of swelling, pain and any threat to the limb.

• Bleeding risk, other medical conditions and functional needs.

• The likely benefit of a procedure compared with medication alone.

A smaller or less symptomatic clot may be best managed without an intervention. Having access to modern technology is useful when it supports the right decision for the patient.

Can clot removal prevent long-term leg problems?

Some people develop persistent swelling, aching, skin changes or ulcers after a DVT. This is called post-thrombotic syndrome and can reflect lasting vein obstruction or damage to the valves.

Removing clot may improve symptoms in appropriately selected patients, but it cannot guarantee that the leg will return completely to normal or that post-thrombotic syndrome will be prevented. Results vary with the clot, the vein and the individual.

Follow-up remains important whether treatment involves medication alone or a procedure. Persistent symptoms deserve review and a management plan suited to their cause.

What about clot removal from the lungs?

The video also describes aspiration treatment for pulmonary embolism, where a clot blocks arteries in the lungs. Catheter-based removal is an option in selected serious cases, within an urgent specialist treatment pathway.

Many pulmonary embolisms are treated with anticoagulation. More advanced treatment is considered according to the effects on the circulation and heart, the person's condition and the risks of treatment. It is not a routine extension of every DVT procedure.

What should I discuss before treatment?

Ask what the proposed treatment aims to achieve, what medication alone is expected to do, and which risks apply to you. Depending on the procedure, risks can include bleeding, vessel injury, problems related to contrast and the need for further treatment. Recovery and follow-up requirements should also be clear.

The DVT treatment guide brings together medicine, selected clot-removal procedures, venous stenting and follow-up.

New one-sided leg swelling or pain needs urgent assessment. Sudden breathlessness, chest pain or fainting can indicate pulmonary embolism and requires emergency care. Call 995 in Singapore; do not wait for a routine appointment.

For non-emergency advice, read more about DVT treatment or contact my clinic at Mount Elizabeth Novena Specialist Centre, #09-22, 38 Irrawaddy Road, Singapore 329563. I can discuss which options fit your diagnosis and circumstances.

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.