Deep Vein Thrombosis (DVT)

A deep vein thrombosis (DVT) is a blood clot that typically forms in a deep vein of the leg, and which can result in a pulmonary embolism.

When your blood coagulates or sticks together, it forms a clot. Small clots are common and often reabsorb into your system without notice, but when a clot does not reabsorb it can result in thrombosis – a blood clot that either partially or totally obstructs a blood vessel. When this blood clot forms in a vein, it is known as venous thromboembolism (VTE), which consists of two separate but related conditions:

• Deep vein thrombosis (DVT): This blood clot typically forms in a deep vein of the leg or occasionally in the arm, and can lead to more serious conditions, including post-thrombotic syndrome (also known as post-phlebotic syndrome). This condition can cause significant swelling, pain and skin discoloration. In severe cases, skin erosions or ulcers can occur and become chronic.
• Pulmonary embolism (PE): This is a blood clot that typically starts as a deep vein thrombosis in the leg and then travels to the lungs, where it becomes trapped and can block the flow of blood to pick up oxygen. A pulmonary embolism is not always fatal, but it can cause cardiac arrest and sometimes death. A condition called chronic PE can also occur, where the flow of blood to pick up oxygen in the lungs is permanently altered, and severe symptoms such as shortness of breath and high pressure in the arteries to the lungs (pulmonary hypertension) can occur.

Deep vein thrombosis: Causes and risk factors

Slow circulation may cause blood to pool, which can lead to the development of a clot or thrombus. As a result, people whose blood circulation has slowed due to sickness, injury or extended periods of inactivity are at an increased risk for developing a thrombosis, including a DVT. Other risk factors for developing deep vein thrombosis include:

• A family or personal history of DVT
• Undergoing recent surgery (inactivity)
• Being over the age of 40
• Use of hormone therapy or oral contraceptives, especially with smoking
• Being pregnant or in post-partum time period
• A history or presence of cancer
• Abnormalities in your blood’s ability to coagulate (often genetic)
• Obesity
• Having certain types of inferior vena cava (IVC) filters

Often, there is a combination of two or more factors (for example, oral contraceptives, smoking and a long car trip) that result in a DVT.

Types of deep vein thrombosis

DVTs are categorized according to how long the thrombosis has been present or identified, and include two types. The age of the thrombosis is usually estimated both by the onset of symptoms (for example, swelling that began one day ago) and by the appearance of the thrombus on ultrasound.

• Acute: Acute deep vein thrombosis refers to new or previously undiagnosed clots. These are typically present for two weeks or less.
• Chronic: Chronic deep vein thrombosis refers to old or previously diagnosed clots.

Deep vein thrombosis symptoms

• Symptoms are variable, but may include:
• Swelling of the affected limb
• Pain in the affected limb
• Difficulty walking
• One limb that feels warmer or colder or is discolored when compared to the unaffected limb

Deep vein thrombosis treatment

Henry Ford Interventional Radiologists offer several treatments for DVT, including:

• Catheter-directed thrombolysis: Infusing drugs over time to dissolve the thrombosis.
• Ekos® or Trellis®: These thrombolysis devices break down the clot by using the drug tPA (tissue plasminogen activator), ultrasound or mechanically fragmenting the clot with a catheter (tube).
• Balloon angioplasty and stenting: Inserting a balloon catheter into the narrowed or blocked vein. The balloon is inflated to open the vein and in some cases, a stent (metal mesh tube) is inserted to help keep the vein open. This is not required in all DVT treatments, but is more commonly used in the setting of chronic DVT where the vessel lining is abnormal and may not stay open on its own.

Our Interventional Radiologists are experts in the use of IVC filters to help prevent a DVT from traveling to the lungs and becoming a pulmonary embolism. Your particular deep vein thrombosis treatment will depend on the size of the clot, its location and other factors.

Deep vein thrombosis research

In addition, our department was recently engaged with the Henry Ford Vascular Surgery, Medicine and Emergency departments in the NIH ATTRACT study, which sought to determine the most effective means of addressing venous clots in the legs and pelvis. This aggressive treatment is undertaken with the intent of avoiding post-thrombotic syndrome.