Dr. John Bartholomew discusses Factor V Leiden, a blood clotting disorder.

Blood Clot Formation

When you cut or injure yourself, your body stops the bleeding by forming a blood clot. Proteins and particles in your blood, called platelets, stick together to form the blood clot. The process of forming a clot is called coagulation. Normal coagulation is important during an injury, as it helps stop a cut from bleeding and starts the healing process.

However, the blood shouldn’t clot when it’s just moving through the body. If blood tends to clot too much, it is referred to as a hypercoagulable state or thrombophilia.

Blood clot formation

Are hypercoagulable states dangerous?

Hypercoagulable states can be dangerous, especially when these conditions are not properly identified and treated. People with hypercoagulable states have an increased risk for blood clots developing in the arteries (blood vessels that carry blood away from the heart) and veins (blood vessels that carry blood to the heart). A clot inside a blood vessel is also called a thrombus or an embolus.

Blood clots in the veins or venous system can travel through the bloodstream and cause deep vein thrombosis (a blood clot in the veins of the pelvis, leg, arm, liver, intestines or kidneys) or a pulmonary embolus (blood clot in the lungs).

Blood clots in the arteries can increase the risk for stroke, heart attack, severe leg pain, difficulty walking, or even the loss of a limb.

What causes hypercoagulable states?

Hypercoagulable states are usually genetic (inherited) or acquired conditions. The genetic form of this disorder means a person is born with the tendency to form blood clots. Acquired conditions are usually a result of surgery, trauma, medications or a medical condition that increases the risk of hypercoagulable states.

Inherited hypercoagulable conditions include:

  • Factor V Leiden (the most common)
  • Prothrombin gene mutation
  • Deficiencies of natural proteins that prevent clotting (such as antithrombin, protein C and protein S)
  • Elevated levels of homocysteine
  • Elevated levels of fibrinogen or dysfunctional fibrinogen (dysfibrinogenemia)
  • Elevated levels of factor VIII (still being investigated as an inherited condition) and other factors including factor IX and XI
  • Abnormal fibrinolytic system, including hypoplasminogenemia, dysplasminogenemia and elevation in levels of plasminogen activator inhibitor (PAI-1 )

Acquired hypercoagulable conditions include:

  • Cancer
  • Some medications used to treat cancer, such as tamoxifen, bevacizumab, thalidomide and lenalidomide
  • Recent trauma or surgery
  • Central venous catheter placement
  • Obesity
  • Pregnancy
  • Supplemental estrogen use, including oral contraceptive pills (birth control pills)
  • Hormone replacement therapy
  • Prolonged bed rest or immobility
  • Heart attack, congestive heart failure, stroke and other illnesses that lead to decreased activity
  • Heparin-induced thrombocytopenia (decreased platelets in the blood due to heparin or low molecular weight heparin preparations)
  • Lengthy airplane travel, also known as "economy class syndrome"
  • Antiphospholipid antibody syndrome
  • Previous history of deep vein thrombosis or pulmonary embolism
  • Myeloproliferative disorders such as polycythemia vera or essential thrombocytosis
  • Paroxysmal nocturnal hemoglobinuria
  • Inflammatory bowel syndrome
  • HIV/AIDS
  • Nephrotic syndrome (too much protein in the urine)