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Causes of Deep Vein Thrombosis (DVT)

Deep vein thrombosis (DVT) occurs when a blood clot forms in a vein deep inside a muscle in your body. It usually happens in the legs, but can also develop in your arms, chest, or other areas of your body. And though DVT is common, it can be dangerous. The blood clot can block your circulation or lodge in a blood vessel in your lungs, brain, heart, or other area. The clot can cause severe organ damage and even death -- within hours.

The main cause of DVT is poor blood flow. When circulation slows, blood can pool and more easily form clots, raising your DVT risk.

Recommended Related to DVT (Deep Vein Thrombosis)

10 Questions You Should Ask Your Doctor About DVT

DVT stands for deep vein thrombosis, a blood clot in one of the body’s deep veins, usually deep within the leg. The biggest danger of DVT is that part of the clot could break off and travel to the lungs, where it can cause a blockage known as a pulmonary embolism, or PE, says Marc Passman, director of the vein program at the University of Alabama at Birmingham. Your doctor will talk to you about how much of a risk your clot poses.

Read the 10 Questions You Should Ask Your Doctor About DVT article > >

Deep Vein Thrombosis Caused by Surgery

Certain surgeries can raise your risk of a blood clot. They include:

  • Surgery that reduces blood flow to a part of your body.
  • Major surgery on a hip, knee, leg, calf, abdomen, or chest.
  • Orthopedic surgery, such as a hip replacement.

These are some of the reasons why surgery can increase your DVT risk:

  • Tissue debris, protein, and fats may move into veins following surgery.
  • Vein walls can become damaged, which may also release substances that promote blood clotting.
  • Prolonged bed rest is common following surgery and can allow blood to pool in areas of the body.

Conditions or Treatments That Raise DVT Risk

Surgery isn't the only cause of DVT. Certain medical conditions or treatments may also increase your DVT risk. For starters, any condition that requires bed rest for more than three days increases your DVT risk. Other risk factors, in order from most common to least, include:

  • An injury that reduces blood flow to part of your body, such as a broken hip or leg.
  • Cancer, even during treatment.
  • A previous history of deep vein thrombosis or pulmonary embolism.
  • An inherited condition that increases blood clotting.
  • Paralysis from a spinal cord injury.
  • Current use of hormone therapy, including that used for postmenopausal symptoms or birth control pills.
  • Pregnancy or having recently given birth, especially by C-section.
  • Varicose veins, which are swollen, twisted, painful veins.
  • A history of heart attack, stroke, or congestive heart failure.
  • Inflammatory bowel disease.

Lifestyle Factors That Raise DVT Risk

Your DVT risk increases with age, especially after 60. There are lifestyle factors that can also contribute:

  • Sitting or inactivity for a long time.
  • Long plane flights or long car trips.
  • Extra weight.
  • Smoking.

Less Common Causes of DVT

Although rare, DVT can occur in the upper body. Factors that can raise your risk of developing DVT in the upper body include:

  • Insertion of a long, thin, flexible tube (catheter) in an arm vein.
  • Insertion of a pacemaker or implantable cardioverter defibrillator (ICD) for certain heart conditions.
  • Cancer near a vein.
  • Repeated vigorous activities using your arms (very rare).


WebMD Medical Reference

Reviewed by Michael W. Smith, MD on February 08, 2012

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