Understanding deep vein thrombosis (DVT)


In this article:

  • Nearly one million people a year are affected by a blood clot, but the condition is often underdiagnosed and untreated until serious health complications occur.

  • Deep vein thrombosis, or DVT, occurs when a blood clot forms in one of your body’s deep veins located in your thigh, lower leg, pelvis or arm.

  • A heart expert from Swedish explains DVT, outlines the warning signs and shares tips to help prevent this potentially deadly condition.

Although an estimated 900,000 people are affected by a blood clot every year, the condition is often underdiagnosed, according to the U.S. Centers for Disease Control and Prevention (CDC). And that could have significant health consequences if the clot is a deep vein thrombosis (DVT).

DVT occurs when a blood clot forms in a vein located deep inside your body. They most often develop in the thigh, lower leg or pelvis, but they can also develop in the arm in some cases. If left untreated, DVT can lead to disability or even death. Knowing the warning signs could save your life. Jose L. Trani, M.D., a board-certified vascular surgeon at Swedish, explains deep vein thrombosis and shares tips on recognizing the signs of this potentially serious health condition.

Understanding DVT

Your heart keeps the blood moving through your arteries, sending oxygen rich blood throughout your body. Your veins return oxygen-poor blood back to your lungs. From there, the newly oxygenated blood returns to the arteries to again travel through the rest of your body, nourishing your organs and tissue. The process happens between 60 to 100 times a minute every day.

DVT affects your veins, not your arteries.

“One of the misconceptions people have is that they consider all vessels to be veins. But veins are specifically vessels that bring blood from the feet back to the heart, as opposed to arteries, which take blood from the heart down to the feet,” says Dr. Trani.

“Unlike on the arterial side where the heart acts as a big pump to push blood through the vessels, on the vein side you rely on muscles around the veins – not in the wall of the vein, but around the vein. When those muscles contract, they compress the vein, pushing the blood through it. The vein has no muscle of its own,” he explains.

When you have a deep vein thrombosis, the blood that is typically a liquid has become a solid – or a blood clot – and this blocks a vein from allowing blood to flow through it on its return trip to the heart.

Without proper care, a portion of the clot can break loose and travel through your bloodstream into your lungs, causing a pulmonary embolism (PE). If the PE remains small, it can often be treated successfully. However, if the clot is large, it could be fatal if the blockage disrupts circulation for too long.

Warning signs

Pain, swelling and inflammation of the leg are the most common signs of DVT. But roughly half of the people with DVT have no symptoms. An estimated 40% of all cases go undetected because there are no warning signs until a more serious condition develops, according to the National Institutes of Health.

“If you do have visible signs, the leg can be red and tender to touch. Some people will describe it as heavy. When you look at it relative to your other leg, it will appear to be larger in size,” says Dr. Trani.

Watch for:

  • Swelling in one of your arms or legs.
  • Pain or tenderness with no known cause.
  • Warmth and tenderness in the affected area.

If you develop a PE, it is a serious medical emergency. Contact your doctor immediately or go to the nearest emergency room.

Signs of PE include:

  • Excessive sweating.
  • Unexplained shortness of breath.
  • Coughing up blood.
  • Rapid heart rate.
  • Chest pain that worsens when inhaling deeply or coughing.
  • Dizziness.
  • Extreme sweatiness.

What causes DVT?

Immobility and inflammation are the two leading causes of DVT, according to Dr. Trani.

“Immobility can be an issue for people who travel for an extended time,” he says. “If you're sitting in an airplane, you’re not moving around very much, your muscles aren’t moving, and they aren’t pushing the blood forward. That causes the blood to sit there. And when blood sits, it becomes more prone to clotting.”

Inflammation occurs when your tissues are damaged, causing them to release chemicals that make your blood vessels leak fluid. This inflammatory response increases your blood’s tendency to clot.

If you combine the two, it dramatically increases the chances of DVT.

“The classic combination is people who have had orthopedic leg procedures. You have inflammation as a result of the surgical procedure. And then you’ve got some immobility – you’re not moving that leg, you’re in bed, or that leg is in a cast, knee immobilizer or brace,” says Dr. Trani. “And that combination is a big setup for developing a blood clot.”

Other factors that increase your risk of DVT include:

  • Family or personal history of increased clotting.
  • Pregnancy.
  • Obesity.
  • Birth control containing estrogen.
  • Trauma that damages a vein.
  • · Smoking.
  • Surgery, especially orthopedic procedures.

Diagnosis and treatment

“The quickest and simplest way to diagnose DVT is ultrasound. It’s the gold standard,” says Dr. Trani. “Ultrasound is a way of looking at the veins without radiation. It’s a simple, readily available test that you can have at most urgent care centers, emergency departments and a lot of outpatient, freestanding facilities.”

Treatment for DVT generally includes medication called an anticoagulant to keep new clots from forming. In some cases, surgery may be required to place a filter into the main vein leading into your heart to reduce the likelihood of a pulmonary embolus.

Compression stockings are often used to treat swelling and prevent skin changes that may occur with DVT. Your doctor may recommend a sequential compression device that uses air pressure to massage your legs and increase blood flow.

Reduce your risk

When it comes to being sedentary, how do you know how long is too long? It varies, according to Dr. Trani.

“I don’t think there is a hard and fast definition, but most people should move and stretch after four to five hours. However, that being said, for some people, DVT can develop within much less time,” says Dr. Trani.

There are several things you can do to reduce your risk of DVT.

According to the CDC, blood clots can be prevented if you:

  • Know your risks and recognize the warning signs of DVT.
  • Inform your doctor of any risk factors you have.
  • Talk to your doctor about blood clots before you have surgery.
  • Contact your physician or seek emergency care immediately if you experience any symptoms.

“Move regularly, even if it's just walking up and down the airplane aisle occasionally or stopping to stretch regularly during long car trips. Don’t smoke and keep an eye on your blood pressure and weight,” says Dr. Trani.

Learn more and find a provider

The team of specialists at the Swedish Heart & Vascular Institute has access to the latest treatments and technology and the expertise to know how to use it safely and effectively. Call 206-320-4100 to learn more about the vascular care we offer.

Whether you require an in-person visit or want to consult a doctor virtually, you have options. Contact Swedish Primary Care to schedule an appointment with a primary care provider. You can also connect virtually with your provider to review your symptoms, provide instruction and follow up as needed. And with Swedish ExpressCare Virtual you can receive treatment in minutes for common conditions such as colds, flu, urinary tract infections and more. You can use our provider directory to find a specialist or primary care physician near you.

Information for patients and visitors

Related resources

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This information is not intended as a substitute for professional medical care. Always follow your health care professional’s instructions.

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About the Author

The Swedish Heart & Vascular Team is committed to bringing you many years of expertise and experience to help you understand how to prevent, treat and recover from cardiovascular diseases and conditions. From tips to eating better to exercise and everything in between, our clinical experts know how to help you help your heart.

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