Deep vein thrombosis (DVT) refers to a blood clot, or thrombus, that forms in a deep vein. That’s a vein deep in your body, as opposed to the ones you can see just under your skin. DVT usually affects the legs, but a clot can form anywhere you have veins. When you get one of these clots more than once, that’s recurrent DVT.
DVT recurrence can cause serious health problems and even death. If you have a history of blood clots, make sure your doctor knows. Ask about ways to prevent or treat recurrent DVT.
Who’s At Risk for Recurrent DVT?
Anyone can develop a deep-vein blood clot at some point in their life. About 2% to 5% of people do. And once you’ve had DVT, you’re a lot more likely to get it again. About 3 in 10 people get a second clot within a decade of their first. But your risk goes down with time. You're most likely to get another clot in the first months or years after the initial one.
While some people get “unprovoked” blood clots, which means there’s not a clear cause, most people have a known risk factor behind their DVT.
Some of the most common risk factors for “provoked” DVT are:
- Major surgery, especially on your hip, pelvis, or knee
- Serious vein injury from an accident or bone break
- Bedrest, paralysis, or inability to walk
- Age over 65
- A BMI (body mass index) of 30 or higher
- Heart failure or kidney problems
- Varicose veins
- Type A blood
Other factors that raise the chances of recurrent DVT include:
Previous clots. Your odds of DVT go up if you’ve already had one or more blood clots. You can get recurrent DVT in the same leg or the opposite one.
Genetics. Around 20% to 40% of people who have DVT with no other clear risk factors have thrombophilia. This means they’re predisposed to blood clots. This can be inherited, though it can also develop for other reasons.
Acquired thrombophilia. You can also develop certain types of thrombophilia later in life that raise your risk for blood clots.
The chances of DVT seem to be highest in people with brain, pancreatic, stomach, ovarian, lung, kidney, or colon cancers. But it can happen in people with other cancers, too.
If you have active cancer, the following factors can raise your chances of blood clots even more:
- Some types of chemotherapy
- Surgery to remove cancer
- Having a catheter in a large vein
- Having other DVT risk factors in addition to cancer
Higher estrogen levels. DVT seems to be more common in males overall. But in females the hormone estrogen can boost levels of proteins in your body, called “clotting factor,” that help blood clots form naturally.
For these reasons, your odds of DVT go up if you’re:
- On combined estrogen-progestin hormonal birth control
- Taking hormonal therapy with estrogen
If you have a history of blood clots, tell your doctor about it when you want to get pregnant, take hormonal birth control like the Pill or patch, or need to use estrogen-related hormones for another reason. They’ll let you know what’s safe for you.
What Are the Complications of Recurrent DVT?
Recurrent DVT is a serious health condition, and it can lead to other dangerous conditions. They include:
Pulmonary embolism (PE). This is when a piece of a blood clot breaks off and travels to your lungs. Your doctor can treat a small one quickly. But a big clot can block blood from getting to your lungs, and it can be fatal.
Call 911 or get medical help right away if you have symptoms such as:
Chronic venous insufficiency (CVI). DVT can damage your veins so they don’t work very well. This usually happens in your leg. Blood can collect in your veins instead of flowing back to your heart. It’s usually not a serious health problem, but CVI can be uncomfortable.
If left untreated, you may have:
- Pain and swelling
- Cramps or a tight feeling in your legs
- Leg sores
- Changes in skin color
- Misshapen, big veins (varicose veins)
Post-thrombotic syndrome (PTS). Around 20% to 50% of people with DVT develop this long-term issue. Your odds are higher if you have recurrent blood clots, are older, and have a higher body weight.
PTS can look like CVI or recurrent DVT. Your doctor can help you tell the difference. Let them know about any new or worsening symptoms, especially if you have leg pain so bad you can’t walk or work. You may also have:
- Skin thickening
- Pain and swelling
- Leg sores that don’t heal
How Do You Prevent or Treat Recurrent DVT?
Before your doctor determines the best treatment for your DVT, they’ll consider several factors, including why you got DVT in the first place. They’ll ask about recent surgeries, prolonged bed rest, and any family history of blood clots. After they pinpoint the cause -- or if they don’t find a clear cause -- your treatment plan might include:
Blood thinners. Also called anticoagulants, they’re the main treatment for DVT. Blood thinners help prevent a blood clot from forming, growing, or traveling somewhere else in your body. You might take this medication by mouth, through a vein in your arm, or under your skin.
You may need to take blood thinners only in specific situations or for a long time, such as:
- Before surgeries or during hospital stays
- 3-2 months after you have a blood clot
- Indefinitely, if you have active cancer or ongoing DVT risk factors
You can have recurrent DVT while on anticoagulation, but your chances go way down. Some studies show about 2% to 5.5% of people with either DVT or PE have a recurrence within the first 3 months of treatment.
Ask your doctor about risks and side effects. The most common side effect of anticoagulants is an increased risk for bleeding. If you’re on blood thinners, tell your dentist or surgeon before any procedures.
Compression stockings. These are tight socks that go up to your knee or groin. They boost blood flow from your lower limbs back to your heart. They can lower the odds of new blood clots and ease pain and swelling from conditions like post-thrombotic syndrome.
Other treatments. You may need different or additional therapies if your DVT is serious or you can’t take blood-thinning medication. Your other options may include:
- Drug therapy to break up blood clots (thrombolytic therapy)
- Nonsurgical treatment to remove blood clots (mechanical thrombectomy)
- Surgical implants in your veins to prevent clots (vena cava filters)
Preventive lifestyle changes. Talk to your doctor about other ways to prevent recurrent DVT. Some strategies they might suggest include:
- Walk around every hour or so during long car or plane trips
- Move around as soon as you can after surgery or illness
- Wear compression socks at home or while recovering from surgery
- Maintain a healthy weight
- If you smoke, quit
When to Call Your Doctor
If you have another blood clot, you’ll need fast treatment. Reach out to your doctor right away if you have any of the following symptoms of DVT recurrence:
- Swelling in one leg or arm
- Pain or cramping, kind of like a charley horse or pulled muscle
- Red or blue tint to your skin
- Warm or tender area on your leg or arm
Your regular doctor can refer you to a blood clot specialist for ongoing care. You can also get more information and additional support through national groups such as: