A short story: what would you do?
Follow Lola Nena to learn the warning signs and what to do. Turn on your sound for the narration.
What happens
Veins carry blood back to the heart. When blood moves slowly, as when you are in bed or sitting for a long time, or when a vein is injured, a clot can form in a deep vein of the leg. This is a deep vein thrombosis (DVT). [Ref: AHA VTE Symptoms] [Ref: ESVS 2021 Venous Thrombosis]
A piece of the clot can break off, travel through the heart and block an artery in the lungs. This is a pulmonary embolism (PE). It strains the heart and lowers the oxygen in your blood. Together, DVT and PE are called venous thromboembolism (VTE). [Ref: ESC 2019 PE] [Ref: AHA/ACC 2026 PE]
How common are these clots?
In studies mostly from Western countries, PE affects 39 to 115 people, and DVT 53 to 162 people, out of every 100,000 each year. Clots are about 8 times more common in people aged 80 and older than in people in their 40s. [Data: ESC 2019 PE epidemiology]
Filipinos and other Asian groups have a lower risk than White populations, but clots still happen and can be life-threatening. [Data: Tran 2019] In early results from a Philippine Heart Association study of 326 people with cancer at 10 hospitals in Luzon, Visayas and Mindanao, about 1 in 7 (14.7%) developed a clot within 6 months of diagnosis. [Data: PHA PINAS-VTE]
Signs of a DVT
SwellingUsually in one leg only.
Pain or tendernessOften in the calf or thigh.
Warm skinThe leg may feel warmer than the other.
Red or darker skinA change in skin colour over the area.
[Ref: AHA VTE Symptoms]
See a doctor today if you have these leg signs
A DVT needs to be checked with an ultrasound the same day. If you also feel short of breath or have chest pain, go to the emergency room now. [Ref: AHA VTE Symptoms] [Ref: ESVS 2021 Venous Thrombosis]
A vein just under the skin that turns hard, red and painful is a different kind of clot. Read about superficial vein thrombosis →
Who is at risk
- Recent surgery, injury, serious illness or a hospital stay, especially with long bed rest. [Ref: ESC 2019 PE] [Ref: ESVS 2021 Venous Thrombosis]
- Long periods of not moving, such as long trips by plane, bus or car. [Ref: ESC 2019 PE] [Ref: ESVS 2021 Venous Thrombosis]
- Cancer and some cancer treatments. [Ref: ESC 2019 PE] [Data: PHA PINAS-VTE]
- Pregnancy and the weeks after giving birth, and hormone treatments such as some birth control pills or hormone replacement. [Ref: ESC 2019 PE]
- Older age, being overweight, and a past clot or a family history of clots. [Ref: ESC 2019 PE]
What happens at your check-up
A clot cannot be confirmed or ruled out at home. Your doctor will ask about your symptoms and risk factors, and examine your legs, heart and lungs. [Ref: ESC 2019 PE] [Ref: AHA/ACC 2026 PE]
Leg vein ultrasound
The main test for a DVT. It is painless and uses no radiation. [Ref: ESVS 2021 Venous Thrombosis]
Blood tests
A blood test called D-dimer can help your doctor decide whether more tests are needed. It cannot tell you on its own whether you have a clot. [Ref: AHA/ACC 2026 PE]
Scan of the lungs
If a clot in the lungs is suspected, your doctor may request a CT scan of the lung arteries. [Ref: AHA/ACC 2026 PE]
Heart checks
If a PE is found, a heart ultrasound and blood tests show how much the clot strains the heart. This helps your doctor decide whether you can be treated at home or need to stay in hospital. [Ref: AHA/ACC 2026 PE]
Your doctor decides which tests you need and explains what the results mean for you.
Worried about a clot? Get checked by a doctor.
Only an examination and the right tests can tell whether you have a clot and how it should be treated. Dr. Aaron Christopher P. Novales sees patients with blood clots in the legs and lungs.
Short of breath, chest pain or fainting? Do not wait for a clinic visit. Go to the emergency room now →
How DVT and PE are treated
About the medicines on this page
Medicines are described here only to help you understand your doctor's plan. Do not buy or take any medicine because you read about it here. Take only what your doctor prescribes for you, and never start, stop or change a dose on your own.
Blood-thinning medicine (anticoagulants)
This is the main treatment. It stops the clot from growing and new clots from forming while your body slowly breaks down the clot. [Ref: AHA/ACC 2026 PE] [Ref: ESVS 2021 Venous Thrombosis]
Your doctor chooses the medicine, the dose and how long you take it, based on what caused the clot, your other conditions and your risk of bleeding. Tell your doctor if you are pregnant or breastfeeding, have cancer or liver disease, or take other medicines. [Ref: AHA/ACC 2026 PE]
Home or hospital
Many people with a DVT, and some with a mild PE, can be treated at home with close follow-up. People with a more serious PE are treated in hospital. Only your doctor can decide which is safe for you, after examining you and reviewing your tests. [Ref: ESVS 2021 Venous Thrombosis] [Ref: AHA/ACC 2026 PE]
Treatment for severe PE
A large clot that strains the heart is an emergency. In hospital, doctors may use stronger treatments to dissolve or remove the clot and support the heart and lungs. This is why breathlessness or chest pain must never be managed at home. [Ref: AHA/ACC 2026 PE]
How long treatment lasts
Treatment usually lasts at least 3 months. At your follow-up visits, you and your doctor decide together whether to stop or continue, based on what caused the clot and your risk of bleeding. [Ref: AHA/ACC 2026 PE]
Important: staying safe on a blood thinner
Never stop it on your ownTake it exactly as prescribed. Ask your doctor before stopping or skipping any dose, even before a procedure.
Tell every doctor and dentistAlso tell your pharmacist and your family that you take a blood thinner.
Watch for unusual bleedingCall your doctor right away if your urine turns red or dark brown, your stools turn red, black or dark brown, your gums bleed, you bruise easily, your periods are very heavy, or you feel weak, faint or dizzy.
Go to the emergency room now if you have a very bad headache or belly pain that does not go away, or if you fall or have any accident, especially if you hit your head. [Ref: AHA 2023 Blood Thinners]
Recovery and follow-up
A follow-up visit or call in the first week after discharge. It goes over what you need to know, checks that you can get and take your blood thinner, and looks for any bleeding. [Ref: AHA/ACC 2026 PE]
A clinic visit to decide whether to continue your blood thinner, check whether you need more tests and ask about lasting symptoms. [Ref: AHA/ACC 2026 PE]
At every visit, your doctor asks about breathlessness or reduced stamina. [Ref: AHA/ACC 2026 PE]
After a PE: breathlessness that lingers
See your doctor if you are still short of breath or tire easily after 3 months of treatment. In a few people, the clot leaves lasting damage in the lungs that needs further tests and specialist care. [Ref: AHA/ACC 2026 PE]
After a DVT: leg symptoms that last
Some people develop long-term leg aching, swelling, heaviness or skin changes, called post-thrombotic syndrome. See your doctor, who can advise on stockings and other care. [Ref: ESVS 2021 Venous Thrombosis]
Your feelings matter too
Anxiety and low mood are common after a PE. Your doctor may ask a few questions at follow-up visits to check for them, and help is available. [Ref: AHA/ACC 2026 PE]
Prevention
In hospitalAsk whether you need medicine or leg devices to prevent clots, and get up and walk as soon as you are allowed. [Ref: AHA VTE Symptoms] [Ref: ESVS 2021 Venous Thrombosis]
After a PEWalking early is better than bed rest. [Ref: AHA/ACC 2026 PE]
On long tripsGet up and walk when you can, and flex your ankles and calves often. If you have had a PE, ask your doctor before long trips whether you need compression stockings or other protection. [Ref: AHA/ACC 2026 PE] [Ref: AHA VTE Symptoms]
Pregnancy and birth controlIf you could become pregnant, ask about birth control and what to do if you become pregnant while on a blood thinner. [Ref: AHA/ACC 2026 PE]
If you had a clot beforeTell your doctor before surgery or hormone treatment, so extra protection can be planned. [Ref: ESVS 2021 Venous Thrombosis]
Talk to your doctor about
Bring these questions to your visit.
- What caused my clot, and could it happen again?
- How long should I take my blood thinner?
- What bleeding signs should I watch for?
- Do I need compression stockings?
- How can I lower my risk before surgery, travel or pregnancy?
Related conditions
Guideline sources for this page
- AHA/ACC 2026 PE: Creager MA, Barnes GD, Giri J, et al. 2026 AHA/ACC/ACCP/ACEP/CHEST/SCAI/SHM/SIR/SVM/SVN Guideline for the evaluation and management of acute pulmonary embolism in adults. J Am Coll Cardiol 2026;87(13):1626–1710; also in Circulation (doi:10.1161/CIR.0000000000001415).
- ESC 2019 PE: Konstantinides SV, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism, developed with the European Respiratory Society. Eur Heart J 2020;41:543–603.
- ESVS 2021 Venous Thrombosis: Kakkos SK, et al. ESVS 2021 Clinical Practice Guidelines on the management of venous thrombosis. Eur J Vasc Endovasc Surg 2021;61:9–82.
- AHA 2023 Blood Thinners: American Heart Association. What are DOACs? (Answers by Heart). 2023.
- AHA VTE Symptoms: American Heart Association. Symptoms and diagnosis of venous thromboembolism.
- Data: ESC 2019 epidemiology as summarized in Intern Emerg Med 2020; PHA PINAS-VTE study; Tran HN, Klatsky AL. Lower risk of VTE in multiple Asian ethnic groups. Prev Med Rep 2019.