Most people know that a clot in a heart artery causes a heart attack. Far fewer know that a clot can also travel to the lungs — a condition called pulmonary embolism. It is more common than most families realise, it is frequently missed because the symptoms look like other things, and it is very treatable when caught in time. This article explains what to watch for.
Where the clot comes from
It usually does not form in the lung. It forms in a deep vein of the leg — a deep vein thrombosis, or DVT. A piece of that clot can break away, travel through the veins to the heart, and lodge in the arteries of the lungs. That is a pulmonary embolism.
This is why leg symptoms and lung symptoms are connected, and why both deserve attention.
Warning signs in the lungs
- Sudden breathlessness, often without any obvious cause
- Chest pain that is sharper when you breathe in deeply or cough
- Coughing, sometimes with blood-streaked sputum
- A racing heartbeat
- Light-headedness or fainting
Warning signs in the leg
These may come first, or not at all:
- Swelling of one leg — usually one, not both
- Pain or tenderness in the calf or thigh
- Warmth, redness or a change in colour over that area
Sudden breathlessness with a fast heartbeat, especially in someone who has recently been immobile, should be treated as a medical emergency. Do not wait to see if it settles.
Who is at higher risk
The most important thing to understand about pulmonary embolism is that it often happens to people who were previously well. Risk goes up after:
- Recent surgery — particularly hip, knee, abdominal or cancer surgery
- A long hospital stay or any period of prolonged bed rest
- A fracture or injury that keeps a leg immobile, including a plaster cast
- Pregnancy and the weeks after delivery
- Hormone tablets, including some contraceptive pills and hormone therapy
- Cancer and its treatment
- Long journeys without moving — long flights, or long road and train journeys
- A previous clot, or a family history of clots
- Certain inherited clotting conditions
How it is diagnosed
If a pulmonary embolism is suspected, the usual steps are a clinical assessment, blood tests including D-dimer, an ECG, and — most importantly — a CT pulmonary angiogram, a special CT scan of the lung arteries that shows the clot directly. An echocardiogram may be done to check the strain on the right side of the heart, and an ultrasound of the legs to look for the source.
How it is treated
Treatment depends on how severe it is, and doctors now use a formal severity grading to decide.
- Most patients are treated with blood-thinning medicines (anticoagulants). These do not dissolve the existing clot directly; they stop it growing and stop new clots forming while the body gradually clears it.
- Some low-severity patients can be treated without a long hospital stay.
- The most severe cases — where the clot is large enough to strain the heart or drop the blood pressure — may need clot-dissolving medicine, or a catheter-based procedure to break up or remove the clot, or rarely surgery.
Blood thinners are usually continued for at least three to six months, and sometimes longer — particularly if there was no clear temporary cause, or if the risk is ongoing. Do not stop them on your own; always ask your doctor first.
Reducing your risk
- Move. On long journeys, walk when you can, and flex your ankles and calves regularly while seated.
- Stay hydrated, especially while travelling.
- Get up early after surgery when your surgical team allows it — early mobilisation is one of the strongest protections there is.
- Take preventive blood thinners exactly as prescribed if you are given them around surgery or hospitalisation.
- Use compression stockings if they have been advised for you.
- Tell every doctor about any previous clot, including before any operation.
The short version
Sudden breathlessness, chest pain that worsens on breathing in, or swelling in one leg — especially in the weeks after surgery, illness, immobility or childbirth — should be assessed the same day. Pulmonary embolism is dangerous mainly when it is not thought of. Once it is diagnosed, it is very treatable.
This article is for general education and is not a substitute for individual medical advice, diagnosis or treatment. Please consult your own doctor about your specific condition.
Dr. Rohan P. Parikh, Interventional Cardiologist, Anand · 24×7 emergency: +91 70690 53852