Deep Vein Thrombosis

The two main complications of deep vein thrombosis (DVT) are pulmonary embolism and post-thrombotic syndrome.

Pulmonary embolism

A Pulmonary embolism is the most serious complication of DVT. It happens when a piece of blood clot (DVT)breaks off and travels through your bloodstream to your lungs, where it blocks one of the blood vessels. In severe cases this can be fatal.

If theclot is small, it might not cause any symptoms. If it's medium-sized, it can cause chest pain and breathing difficulties . A large clotcan cause the lungs to collapse, resulting in heart failure , which can be fatal.

About onein 10people with an untreated DVT develops a severe pulmonary embolism.

Post-thrombotic syndrome

Ifyou've had a DVT, you may develop long-term symptoms in your calf known as post-thrombotic syndrome. Thisaffects around 20-40% of people with a history of DVT.

If you have DVT, the blood clot in the vein of your calf can divert the flow of blood to other veins, causing an increase in pressure. This can affect the tissues of your calf and lead to symptoms, including:

• calf pain
• swelling
• a rash
• ulcers on the calf (in severe cases)

When a DVT develops in your thigh vein, there's an increased risk of post-thrombotic syndrome occurring. It's also more likely to occur if you're overweight or ifyou've had more than one DVT in the same leg.