10 DVT (deep vein thrombosis) facts and figures
In this article we will describe facts and figures about 10 DVT (deep vein thrombosis).
DVT
Deep vein thrombosis (DVT) is a blood clot that develops within a deep vein in the body, usually in the leg.
1. Definition
Deep vein thrombosis (DVT) is a condition in which a blood clot forms in a deep vein, usually in the legs.
Venous thromboembolism (VTE) is an umbrella term encompassing both pulmonary embolism (PE) and deep vein thrombosis (DVT).
2. Symptoms
Common symptoms of DVT include swelling, pain, tenderness, and redness of the skin in the affected area – usually the calf (but can include the thigh, if extensive). Some people may have no symptoms at all.
These symptoms can also occur in the arm or abdomen if the clot is there.
3. Causes
DVT can be caused by clotting disorders, such as injury to a vein, surgery, certain medications, and prolonged periods of immobility (e.g. long flights or bed rest).
4. Risk factors
Risk factors for DVT include age (especially over 60 years), obesity, smoking, cancer, heart failure, varicose veins, genetic predisposition, pregnancy/oral contraceptive (OC) or hormone replacement therapy, and a history (or family history) of DVT or pulmonary embolism.
5. Complications
One of the most serious complications of DVT is pulmonary embolism (PE), which occurs when a clot breaks free and travels to the lungs. They can cause mild or moderate symptoms or be fatal.
If untreated, 10-30% of individuals with a deep vein thrombosis (DVT) will develop a pulmonary embolism.
6. Prevention
Preventive measures include staying active, exercising regularly, maintaining a healthy weight, avoiding prolonged periods of immobility, wearing compression stockings; and, for high-risk individuals (or people who have had 2 or more DVTs), taking blood thinners (warfarin, heparin, direct-acting oral anticoagulant (DOAC)).
Occasionally an inferior vena cava (IVC) filter – inserted by an interventional radiologist – is necessary to prevent further PEs from further DVTs.
7. Diagnosis
DVT is often diagnosed using imaging tests such as ultrasound, venography, or D-dimer blood tests that measure clot formation and breakdown.
DVT shown on venogram
D-dimer
The D-dimer blood test has a high sensitivity but low specificity for VTE (PE and DVT). Many conditions can result in an elevated D-dimer in the absence of VTE:
- Pregnancy
- AKI or AKI on CKD
- Malignancy
- Liver disease
- Severe infection or inflammatory disease
- Disseminated intravascular coagulation (DIC)
- Recent trauma/surgery/hospitalised patients.
Note 1. In these patients, D-dimer testing has no value in diagnosing VTE
Note 2. D-dimer has a good negative predictive value. A negative D-dimer almost certainly excludes DVT (and PE).
8. Treatment
The main treatment for DVT involves anticoagulant medications (blood thinners) like heparin, warfarin, or direct-acting oral anticoagulant (DOAC) to prevent further clotting. In severe cases, clot removal procedures or thrombolytic therapy may be necessary.
The clot dissolves of its own accord. In other words, treatment is used to prevent extension of the clot, or further clots.
Pregnancy. Pregnant individuals with DVT usually need heparin injections throughout pregnancy and up to 6 weeks postpartum.
9. Lifestyle adjustments
Patients diagnosed with DVT are often advised to make lifestyle changes such as quitting smoking, and increasing physical activity to manage the condition and prevent recurrence.
10. Post-thrombotic syndrome
A long-term complication of DVT, post-thrombotic syndrome (PTS), can occur in the affected limb, leading to chronic pain, swelling, and skin changes due to damaged veins.
Summary
We have described 10 DVT (deep vein thrombosis) facts and figures. We hope it has been helpful.
Other resources
10 PE facts
DVT (NHS England)
DVT (NHS Scotland)
