What is a DVT Blood Clot in The Leg?
Medically reviewed by Mohamed T. Hassan, MD, DABVLM, RPVI, on April 24, 2024.
A blood clot is a semi-solid mass of blood cells and other substances that form in your blood vessels. When a blood clot forms in the deep veins of the leg it is known as deep vein thrombosis (DVT). A DVT is a serious condition that requires prompt medical attention.
In the blog, venous and lymphatic vein specialist Dr. Mohamed Hassan, lead vein doctor at Center for Vein Restoration (CVR) vein clinic locations in Hoover, Alabama, and Trussville, Alabama, provides an overview of what blood clots are, how to recognize the signs, and what to do if you suspect that you have a blood clot.
Where are blood clots (venous thrombus) located?
“You can have a blood clot anywhere in your body. Blood clots that happen in the veins in your arms or legs can cause deep vein thrombosis (DVT). Blood clots that develop in your arteries may appear in your lungs, causing a pulmonary embolism (PE). Blood clots that block blood flow to your brain may cause a stroke, and blood clots in your heart may cause a heart attack.” - Dr. Mohamed Hassan
Types of Blog Clots
There are two types of blood clots that can occur in the leg veins. The difference is where they occur: the superficial or deep veins.
Blood clots in the superficial veins
Dr. Hassan: A superficial venous thrombosis (SVT) is the thrombosis of a vein in the superficial network (in the subcutaneous tissue). It typically involves a clot in a varicose vein. Thrombosis can affect not only the varicose branches under the skin but also the saphenous veins into which these branches drain.
Blood clots in the deep veins
Dr. Hassan: There is also a deep vein thrombus (DVT), which affects the deep veins, that is to say, the veins located in the leg muscles. Involvement of the deep veins is more worrying because the thrombosis can extend to the thigh and beyond towards the abdominal veins (iliac veins and vena cava).
Deep vein thrombosis(DVT) of the legs
What are the signs of having a leg DVT?
Dr. Hassan: The two main symptoms of a blood clot in the leg are pain and swelling (edema). Leg pain is most often in the back of the calf and is more or less permanent and persistent. It can cause difficulty walking, which can lead to lameness. It can also affect the thigh.
Edema (swelling) is another important sign. It is usually concentrated around the ankle and calf and is permanent, but it can be of variable importance. When phlebitis affects the veins of the thigh or abdomen, edema can extend to the thigh.
It is important to note that these two signs will not necessarily present together. Pain and edema can exist in isolation. Sometimes, the pain and/or edema can be minimal (or even absent) and not cause any alarm. Blood clots with few or no symptoms are very difficult to diagnose and are often revealed only when a complication occurs.
How is DVT of the legs are diagnosed?
Dr. Hassan provides a summary of deep vein thrombosis diagnosis:
Gently pressing on the skin and underlying tissues
Healthcare providers diagnose DVT through clinical examination, looking for:
- Pain on palpating (feeling) calf muscles
- Pain with ankle flexing/extension
- Skin warmth and leg swelling
- Painful, red, hardened skin (superficial phlebitis)
These findings indicate the presence of a deep vein thrombosis, which may be confirmed with further testing, such as ultrasound.
D-dimer test
In addition to the clinical examination, healthcare providers can use a simple blood test to help diagnose deep vein thrombosis (DVT). This test measures the levels of a substance called D-dimer.
If this biological examination is negative (D-dimer of normal value), it is almost certain that there are no blood clots. On the other hand, an increase in D-dimer can be the consequence of other inflammatory phenomena. It is the clinical context that will guide the diagnosis when faced with an elevation of D-dimer.
Doppler ultrasound
While other tests, like the D-dimer blood test, can provide initial clues, the Doppler ultrasound examination is the most important and definitive diagnostic tool for deep vein thrombosis (DVT). This examination allows for certainty of the diagnosis, making it possible to visualize the precise location of the clot, whether superficial or deep location. It also helps map out how far the clot has spread along the affected limb.
What are the risk factors for a blood clot?
Dr. Hassan provides an overview of the risk factors associated with blood clots:
Restricted movement
First, prolonged immobility or limited mobility (bed rest or sitting position) is a risk factor for blood clot formation. Indeed, the immobility of the lower limbs does not allow the calf muscle pump to drain the blood in the legs, which exposes the blood to stagnation in the venous network. This stagnation promotes the formation of clots in the veins and, therefore, the occurrence of blood clots. One of the best-known situations is long-seated travel, particularly by plane.
Heightened clot risk due to illness, pregnancy, and injury
Additionally, the context of an illness, pregnancy, trauma (particularly if it requires a cast), or surgical intervention are also risk factors. Not only may the patient be bedridden, but also illnesses, trauma, and surgical interventions lead to generalized inflammation in the body, which aggravates the risk of vein inflammation and blood clot formation.
Abnormalities in the blood clotting process
Disorders of the coagulation system, called thrombophilia, can promote blood clot formation. After clots occur, screening via specialized blood tests is recommended to identify the underlying thrombophilic condition. This is valuable, as thrombophilia indicates a higher recurrence risk. Since it often has genetic origins, screening family members is also beneficial to identify at-risk individuals. Knowing one's thrombophilia status enables preventive measures in high-risk situations, improving outcomes.
Lifestyle choices and medications that elevate clotting risks
Other common risk factors are obesity, smoking, and using oral contraception pills. They can be added to the risk factors mentioned above.
What can be the complications of blood clots?
Dr. Hassan: There are two types of complications: acute and chronic.
Acute complications include, first of all, the extension of the clot from the calf towards the thighs and beyond towards the abdomen. This can lead to increased pain and/or swelling.
The most severe acute complication is pulmonary embolism, which occurs when part of the clot in the vein detaches and migrates upwards toward the heart and then the vessels of the lungs, which the clot can block. This complication is potentially fatal because if it is massive (a large clot), it can cause cardio-respiratory arrest.
The postthrombotic syndrome essentially represents chronic complications. This is the consequence of destruction or severe damage to the veins, which can no longer effectively drain venous blood, leading to a chronic increase in venous pressure.
This can lead to permanent swelling (chronic edema) and then to skin lesions, with the skin gradually becoming pigmented, rigid, indurated, and fragile. This can potentially lead to the development of a venous leg ulcer, which has great difficulty healing permanently.
What are the ways to treat blood clots?
Dr. Hassan: Anticoagulant therapy is the primary treatment for blood clots, such as deep vein thrombosis. Anticoagulant medication must be started as soon as a DVT is diagnosed. This helps prevent the clot from growing and reduces the risk of complications.
For first-time DVT patients, anticoagulant treatment is typically required for at least three months. If a person experiences a recurrence of DVT or a pulmonary embolism, they will likely need extended or even lifelong anticoagulant therapy to manage their increased clotting risk.
The other essential treatment for DVT is wearing compression stockings. Venous compression improves venous drainage and limits venous pressure, thus preventing the extension or recurrence of the clot and reducing swelling, inflammation, and pain.
Finally, restoring the patient's walking as soon as possible is essential. Walking promotes venous drainage, thanks to the calf muscles, reducing congestion and the extension of the clot.
In some instances, a DVT may obstruct the pelvic veins (iliac veins). In this situation, the blood clot removal by dilation inside the vein and placement of a stent must be considered. A stent is a small, tubular mesh device inserted into a vein to provide structural support and keep the vein open. Studies show that removing the obstacle prevents the occurrence of postthrombotic syndrome and radically changes patients' quality of life.
How can I prevent deep vein thrombosis?
Dr. Hassan offers ten tips on how to prevent DVT blood clots from occurring:
- Stay active. This will help promote your venous flow and prevent blood stagnation and clot formation
- Maintain a healthy weight. Obesity increases your risk of developing a blood clot
- Stay hydrated
- Avoid prolonged sitting or standing
- Elevate your legs
- Quit smoking
- Manage underlying health conditions
- Follow medication instructions
- Be cautious with hormone therapy and birth control
- Wear compression stockings and take a quick 3-minute walk during long trips every 1-2 hours
Are you concerned about your risk of DVT blood clots?
If your leg suddenly becomes swollen, painful, or reddened, especially if accompanied by shortness of breath or chest pain, it is crucial to seek immediate medical attention, as these could be signs of a dangerous blood clot.
Center for Vein Restoration (CVR) offers a DVT rule-out service for same-day or next-day diagnosis and treatment plans. Our hotline number is 877-SCAN-DVT.
Comprehensive Vein Care from Trusted Experts
The board-certified physicians at Center for Vein Restoration (CVR) are renowned specialists in diagnosing and treating a full range of vein conditions. As America's largest physician-led vein center, CVR is the go-to resource for comprehensive leg health and vein care.
CVR accepts coverage from major insurance providers, including Aetna, Amerigroup, Anthem, Blue Cross/Blue Shield, Cigna, MultiPlan, Medicaid, Medicare, and more. Get the expert vein care you need to restore the health and appearance of your legs.
Call 240-512-4180 to speak with a Patient Services Representative or schedule a consultation at a convenient CVR location near you.