The popliteal vein is one of the major blood vessels in the lower body. It runs up the back of the knee and carries blood from the lower leg to the heart. Sometimes, a blood clot, or a thrombosis, can block this important vein. This is known as a deep vein thrombosis (DVT). It can restrict circulation in your legs. This can cause damage to your blood vessels and the surrounding tissue.

A clot can also break loose from the popliteal vein. It can then travel to the right side of the heart and then to the lungs, where it can cause numerous circulation and respiratory problems. A blood clot in the lungs is called a pulmonary embolism (PE).

It’s important to know how to avoid popliteal vein thrombosis and recognize the symptoms of this potentially life-threatening condition. If you’re at high risk for popliteal vein thrombosis, you should learn more about its risks and how to keep the circulation in your legs as healthy as possible.

The symptoms of a popliteal vein thrombosis include pain, swelling, and tenderness around the area of the clot. While the vein is closer to the surface of the skin in the back of the knee, a clot can form anywhere in the blood vessel. The skin over the affected area may also feel warm to the touch.

The pain, which can start in the lower leg, may feel like a cramp. That’s why it’s important to look for other symptoms such as swelling. A typical muscle cramp doesn’t cause swelling. If you notice that one leg is bigger than the other, get medical help immediately.

A blood clot in your circulatory system can cause a PE. If it reaches the brain, it can cause a stroke. If a clot is lodged in one of the arteries supplying blood to the heart muscle, the result can be a heart attack.

Frequently, a clot can exist without any obvious symptoms. This means you have to be aware of even slight changes in the way you feel or the way your legs look.

If you experience breathing difficulties, it could mean that the clot has traveled to the lungs without you even knowing that it was in your vein.

You should always call 911 or your local emergency services if you’re having trouble breathing.

The two main causes of popliteal vein thrombosis and other forms of DVT are damage to the vein and being bedridden or too sedentary.

Damage to your vein can occur due to:

  • smoking
  • drug use
  • a major injury
  • chronic inflammation, which injures the inner lining of your vein

When your legs are still for prolonged periods and you’re not on your feet walking and moving around, blood flow in the legs gets sluggish. When blood isn’t circulating as it should, it can pool in a part of your vein and form a clot.

If you’ve had knee or hip replacement, or another major operation involving the legs, you’re at an increased risk. This is partly due to being bedridden for a long operation and the recovery period that follows. Tissue from the bones or joints your surgeon is operating on can break off into tiny pieces. This can cause clots in your bloodstream.

Pregnancy can temporarily increase your risk of blood clots. Other risk factors for popliteal vein thrombosis include the following:

  • people who smoke
  • people who are obese
  • women who take birth control pills
  • women who take hormone replacement therapy

Factor V Leiden

Another risk factor is an inherited health condition called factor V Leiden. It’s a mutation of one of the proteins that help control bleeding and clotting. A mutation of the protein means you’re at an increased risk for abnormal clots. You may have factor V Leiden and never experience clotting problems.

If you develop popliteal vein thrombosis or another form of DVT and you have a family history of clotting issues, your doctor may order a test for factor V Leiden. A blood test and a genetic test can help your doctor determine whether you have this inherited condition.

A sudden onset of swelling, tenderness, and pain in the leg could indicate that you have a DVT. If the discomfort and swelling is in the area behind the knee, it may be a popliteal vein thrombosis.

Your doctor will do a physical exam. Following the exam, they may perform an ultrasound of your leg. The ultrasound will focus on the area of the suspected clot. If popliteal vein thrombosis is suspected, your doctor will do an ultrasound of your knee. An ultrasound uses sound waves to create an image of the bones and tissue inside your leg.

They may also order a venography. In this test, they inject a special dye into your vein and take an X-ray. The dye makes the image inside the vein clearer and can reveal whether a blood clot is affecting your circulation.

A blood test called a D-dimer test is also helpful. It tests your blood for a substance released by blood clots. Evidence of D-dimer in your blood suggests a vein thrombosis, but it doesn’t help your doctor locate the clot. The other imaging tests and your physical symptoms will help your doctor locate it.

If your doctor diagnoses you with a popliteal vein thrombosis, the first treatment you’ll receive is anticoagulant therapy. Anticoagulants are medications that interfere with clotting. Some examples are heparin and warfarin (Coumadin, Jantoven).

Newer anticoagulants have been approved, including rivaroxaban (Xarelto), apixaban (Eliquis), and dabigatran (Pradaxa). Anticoagulants and your body’s defenses may help a clot dissolve over time. Use of aspirin for a longer period may also help reduce the risk of new clots forming in your veins.

Depending on where the clot is located and how serious it is, your doctor may need to remove the clot. They can use special catheters to do this, but this isn’t always an option. Clots that are especially difficult to reach may require surgery to remove.

Wearing compression stockings can also improve blood circulation in your lower legs.

Having popliteal vein thrombosis is serious, but it can often be managed or treated if diagnosed in time. If you get treatment for it, there aren’t usually any long-term consequences. Because DVT tends to develop in people with advancing age, obesity, a history of smoking, or other circulation disorders, your doctor will have recommendations about how to avoid future clotting problems.

You may also have to stay on anticoagulant medication, also known as a blood thinner, for the rest of your life. This can raise your risk of bleeding issues, but many people can take this medication without having problems with clotting or bleeding.

Because surgery and prolonged bed rest can lead to vein thrombosis, moving around as soon as possible after surgery is key to preventing popliteal vein thrombosis. You’ll need to follow your doctor’s advice and not risk hurting yourself after surgery, however.

Here are some more ways to help prevent popliteal vein thrombosis and other forms of DVT:

  • If you’re sedentary during the day, try to move around more often. If you have trouble walking, at least stand or move your legs from a seated position.
  • Take medications, especially anticoagulants, as prescribed.
  • If you’re at risk for DVT, your doctor may suggest you wear compression stockings on a regular basis. It may take time to get used to wearing them, but they could help save your life.
  • If you smoke, try to quit as soon as you can. Ask your doctor about smoking cessation groups and treatments.
  • If you’re obese, talk with your doctor about strategies for weight loss.
  • Don’t skip your yearly physicals and regular doctors’ visits.

Preventing popliteal vein thrombosis isn’t always possible, but you can help prevent it if you take care of your health and follow these tips.