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The greatest danger from deep vein thrombosis (DVT) is that the clot will break loose, travel through your blood, and damage an organ.

"The place it gets stuck most commonly is the lungs, and that's called a pulmonary embolism (PE)," says Molly Cooke, MD, of the University of California, San Francisco. Less often, another clot can form and travel to the brain and cause a stroke. If a clot travels to the heart, it could cause a heart attack. A clot in the kidneys can cause kidney failure.

Depending on the size of the clot and where it travels, it could be fatal. But most people who get treatment right away for DVT and PE go on to lead normal lives.

Pulmonary Embolism

A clot in your lung can lower the oxygen levels in your blood, which can damage your other organs. It can also harm the lung itself and put more pressure in the lung's arteries, called pulmonary hypertension.

The most common symptoms of PE are:

Less common ones include:

  • Anxiety
  • Fast heartbeat
  • Feeling lightheaded
  • Sweating
  • Fainting

If you have symptoms, go to a hospital or call 911 right away.

Postthrombotic Syndrome (PTS)

This is another danger of deep vein thrombosis. You could have long-term effects in that leg or arm, including:

  • Pain
  • Swelling
  • Skin color changes

As many as 6 out of 10 people with DVT get postthrombotic syndrome. "This is an important complication that is not well-recognized, even among physicians," says Natalie Evans, MD, a vascular medicine specialist at the Cleveland Clinic.

While it's usually mild, it could become as severe as getting ulcers on the skin of the affected leg.

When you have PTS, the valves in your leg veins have gotten stretched and don't work right. Blood is more likely to pool and form clots. You can't strengthen the valves, so you need to stay active. "The way that blood gets back to the heart from the feet and legs is by being squeezed up by the muscle action in our legs as we walk around," Cooke explains.

Lying with your legs higher than your heart can also help your blood move and reduce swelling and pain.

"Unfortunately, there aren't great preventive strategies for postthrombotic syndrome other than making sure you don't get a DVT," Evans says. Your doctor will probably recommend you wear prescription-strength compression stockings to avoid PTS.


Living With

See the causes, dangers, and treatments of DVT in this slideshow.