Great saphenous vein thrombosis occurs when a blood clot blocks one of your great saphenous veins. Only rarely does it travel to your lungs, possibly causing a dangerous pulmonary embolism.

Your great saphenous veins are the longest veins in your body. You have one in each leg. They return blood from your feet and legs and send it to your femoral veins in your thighs.

Doctors may treat great saphenous vein thrombosis with a combination of medications to break up the blood clot or recommend conservative remedies such as compression socks.

Serious complications are rare, but it’s important to visit your doctor any time you suspect you may have saphenous vein thrombosis.

Read on to learn more about great saphenous vein thrombosis including risk factors, symptoms, and treatment options.

Great saphenous vein thrombosis is a blood clot in your great saphenous vein. It’s considered a type of superficial thrombophlebitis, also called superficial vein thrombosis. Superficial thrombophlebitis is a blood clot in a vein near the surface of your skin.

Superficial thrombophlebitis is a fairly common condition that’s usually a complication of varicose veins. About 3% to 11% of people experience superficial vein thrombosis at some point, and about 60% to 80% of cases occur in the great saphenous vein.

Great saphenous vein thrombosis is often self-limiting but still requires immediate medical attention to help avoid potentially serious complications.

Risk factors for superficial thrombophlebitis include:

In a 2017 study, researchers found that out of 605 people with acute great saphenous vein thrombosis:

Blood clots that form in deeper veins are known as deep vein thrombosis. About a third to half of people with deep vein thrombosis have long-term complications caused by damage to valves inside their blood vessels. Complications can include:

  • swelling
  • pain
  • discoloration
  • ulcers
  • scaling skin

A superficial or deep vein thrombosis that becomes dislodged and travels to your lungs is called a pulmonary embolism. Pulmonary embolism occurs in about 4% of people with superficial thrombophlebitis.

Superficial vein thrombosis is about 2 to 3 times more common than pulmonary embolism and deep vein thrombosis combined.

Thrombosis of your great saphenous vein is often characterized by the following:

  • pain
  • tenderness
  • swelling
  • redness
  • itchiness

You may also see a hard cord under the surface of your skin that hurts when you touch it.

It’s important to visit a doctor or the emergency room right away for prompt medical attention if you develop any potential symptoms of great saphenous vein thrombosis.

To start the diagnostic process, a doctor will examine the affected part of your skin and review your personal and family medical history.

The diagnosis for superficial thrombophlebitis has traditionally been largely clinical, meaning a doctor makes the diagnosis by considering your signs and symptoms.

Doctors now usually perform compression ultrasound to:

  • confirm the diagnosis
  • measure the extent of your blood clot
  • differentiate from a deep vein thrombosis
  • find a co-occurring deep vein thrombosis, which can occur in nearly a quarter of people.

A doctor may also perform a blood test to look for elevated levels of a substance called D-dimer. Most people with a blood clot have high levels of this protein fragment in their blood. However, a D-dimer test has limited benefit since it can’t be used to rule out a deep vein thrombosis.

Your doctor may want to test you for cancer if you’re under the age of 40 and have no risk factors for superficial thrombophlebitis.

Risk of deep vein thrombosis

The Internal Carotid Artery Occlusion Study Group has developed the following point system to estimate the risk of also having deep vein thrombosis in people with superficial thrombophlebitis.

Active cancer1.5
Limb swelling1.5
Age over 501
Rope-like appearance to skin-1
No provoking incident-1

Your chances of having a deep vein thrombosis depend on your point score:

Probably groupScoreChance
Low probabilityLess than 01.1%
Intermediate probability0 to 112%
High probability1.5 or higher32.3%

Superficial thrombophlebitis below your knee generally doesn’t need aggressive treatment, and there remains some debate over the best way to manage it. Treatment options include:

Your doctor will likely recommend anticoagulation medication if you also have deep vein thrombosis or if your blood clot is at a high risk of migrating through your bloodstream.

In the 2017 study, researchers found that 13.4% of people with great saphenous vein thrombosis were treated with aspirin or NSAIDs, and 58.2% were treated with anticoagulation medications.

Compression socks or stockings are often recommended for preventing superficial vein thrombosis, but there’s mixed evidence supporting their benefit.

In a 2018 review, some studies found evidence that wearing compression socks may help prevent the reoccurrence of superficial thrombophlebitis, whereas other studies found no additional benefit when combined with other treatments.

There’s weak evidence that compression socks may help speed up the breakdown of the blood clot.

According to a 2021 review, there’s currently moderate evidence that the chances of developing superficial thrombophlebitis during air travel are reduced by wearing compression stockings. There’s also a high level of evidence that compression stockings can reduce the chances of developing deep vein thrombosis.

Great saphenous vein thrombosis is when a blood clot blocks one of your great saphenous veins. These blood vessels are the longest veins in your body.

Most cases of great saphenous vein thrombosis resolve with medications and other conservative treatments. It’s still important to seek medical attention anytime you suspect you may have a blood clot. In rare cases, the blood clot can reach your lungs and cause a potentially life-threatening complication called pulmonary embolism.