World Thrombosis Day: How DVT and Pulmonary Embolism Can Be Fatal
A clot in the leg can travel to the lungs and become life-threatening. Dr Andrew Choong explains DVT, pulmonary embolism, hospital-associated clot risk and the warning signs that need urgent attention.
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.