Deep Vein Thrombosis: Risk Factors, Treatment, and Prognosis

Published on October 12, 2023 .

Varicose veins on the womans leg — Image by zlikovec via Shutterstock

Deep vein thrombosis (DVT) is when a blood clot forms in your body’s deep veins, typically in your legs. The clot blocks the vein, slowing down or obstructing blood flow. If not treated, the thrombus can dislodge and head toward your lungs, causing a pulmonary embolism, which can be fatal.

DVT is a blood clot (or “thrombus”) that forms in one of the deep veins of your body, typically in the legs.
One of the most alarming consequences of a DVT is a pulmonary embolism (PE). The good news is that PE is preventable.
Any factor that causes your blood to clot or slows the blood flow through your leg’s deep vein can lead to DVT.
Blood thinners can keep your blood from clotting but carry the risk of bleeding, necessitating regular checkups.
Surgery is the next step if you do not respond to adequate medical therapy and lifestyle changes.

What causes DVT?

Any factor that makes your blood more likely to clot or slows the blood flow through your leg’s deep vein can lead to DVT. The most common risk factors are:

Risk factor	Impact
Recent surgery	Prolonged bed rest, reduced physical activity, or damage to the vessel wall can cause the blood to pool in your leg veins, increasing the chance of DVT.
Older age	Reduced physical mobility and a rise in clotting factors can make your blood more prone to clotting as you age.
Sitting still for a long time	Such as during a long plane flight.
Having a vein disease	Especially varicose veins.
Active cancer	Activation of clotting factors, damage to the veins from cancer that has spread, and chemotherapy can all boost your odds of getting DVT.
Obesity	Obesity increases the tendency to develop blood clots, thus leading to DVT.
Having a family history of clotting diseases	History of clotting disorders in your family may lead to DVT.
Infection or inflammation	Some infections or inflammation may improve the risk of getting DVT in the future.
Autoimmune disorders	Disorders like antiphospholipid syndrome and systemic lupus erythematosus also enhance your blood’s tendency to clot.
Pregnancy, as well as the period following birth	During pregnancy, the potential to develop blood clots increases, along with a decline in processes that block blood clotting. Moreover, the pressure from the growing uterus impedes venous return to the heart, causing blood to pool in your leg veins.
Using hormonal birth control methods	Contraceptives, mainly those containing estrogen, carry a two- to six-fold increased risk of thrombosis.

What are the symptoms of DVT?

For some patients, the symptoms may be very mild or go unnoticed. Others may experience symptoms that are severe enough to raise concern. DVT symptoms include:

Throbbing or cramping pain in the affected calf or thigh.
Tenderness confined to the affected calf or along the course of the deep veins in your thigh.
Swelling in the affected calf or thigh.
Feeling warmth near the affected area.
Red or discolored skin near the painful area (due to engorgement and blockage of the vein).
Prominent, stiff, or swollen veins that are tender to touch.

Some people may not experience symptoms or seek treatment until they have one of the most life-threatening consequences of DVT, pulmonary embolism (PE). This condition happens when the blood clot (thrombus) breaks off and travels through your bloodstream to obstruct your lung’s arteries. The symptoms of PE include:

Intermittent shortness of breath.
Sharp, localized chest pain that gets worse as you inhale.
Coughing blood.

How do doctors test for DVT?

When you present with the signs and symptoms of DVT, your doctor will perform a physical evaluation to help detect DVT risk. Next, your provider will run specific tests to help confirm or rule out DVT. The most frequent tests for DVT include:

D-dimer blood assay - Any condition where clots form causes a rise in D-dimer levels, including severe DVT.

Duplex ultrasound - It's the gold-standard non-invasive test for diagnosing DVT. The procedure resembles a simple ultrasound, but unlike a simple ultrasound, it also helps assess the blood flow in the blood vessels of your legs, which helps reveal the site of blockages.

What is the treatment for DVT?

DVT is a potentially serious condition that warrants urgent medical attention. If you experience DVT symptoms, tell your medical provider immediately or go to the emergency department.

The primary goals for treating deep venous thrombosis are to:

Prevent the existing clot from expanding.
Alleviate symptoms and improve the quality of life.
Prevent or cut down the risk of developing pulmonary embolism (PE) or any other complications.
Keep new blood clots from developing.

Several options exist for treating DVT. Your doctor will decide which treatment works best for you.

Medications

Blood-thinning medications, like:

Heparin.
Enoxaparin (Lovenox).
Fondaparinux (Arixtra).
Warfarin (Coumadin).
Dabigatran (Pradaxa).
Rivaroxaban (Xarelto).

These medications work by hindering your blood’s ability to clot. They also slow the growth of active clots and minimize the odds of developing more clots.

Graduated compression stockings

Your doctor may also recommend wearing compression stockings. These stockings exert the most pressure on your ankle, and the pressure gradually diminishes near the sock’s top. The gentle compression of your leg keeps the blood from pooling in your leg veins and mitigates swelling and discomfort.

Your healthcare professional will accurately measure your limb diameter and prescribe stockings that best suit your limb.

Surgery

Doctors prefer surgery over medical treatment for DVT when:

You have a severe form of DVT that does not respond to adequate medical therapy.

You develop post‐thrombotic symptoms. These post‐thrombotic symptoms include pain, swelling, skin pigmentation, or ulcers on the affected leg. Research shows that over 50% of patients on medications may still develop post‐thrombotic symptoms in the long term.

You develop PE or other DVT complications, warranting urgent corrective action.

There are various surgical options for treating DVT.

Thrombolysis

Thrombolysis is a procedure that helps break the blood clot inside the blood vessel. In this procedure, the vascular surgeon injects a clot-busting drug via a tube (catheter) into the clot. Thrombolysis carries a higher risk of bleeding and stroke than medical therapy alone. Nonetheless, it can help dissolve more extensive clots.

Thrombectomy

Surgeons use thrombectomy to remove a clot sited in one of the deep veins when other methods don’t work. This procedure involves making an incision into a blood vessel to get rid of the thrombus. Thus, it puts you at a higher risk of serious complications, including PE.

Inferior vena cava filter

Insertion of an inferior vena cava filter is the treatment of choice if you’re not a good candidate for blood-thinning medications. Your doctor will pass an umbrella-looking filter into the inferior vena cava (IVC). The IVC is a primary vein in your abdomen. It helps transport venous blood from your stomach and lower limbs to your heart.

The IVC filter works to capture the thrombus that breaks away before it can reach your lungs and cause PE. That said, IVC filters neither treat DVT nor PE once it has developed.