What is Thrombosis?

Blood clotting is a normal, complex process that prevents excessive bleeding when a blood vessel is injured. Sometimes, clots form inside a blood vessel when they shouldn’t. Clots can occur in arteries and veins. Arteries are the blood vessels that carry blood away from the heart, to the legs and the arms, the abdomen and the brain. Veins are the blood vessels that carry blood back to the heart from the extremities, the abdomen and the brain. Blood clots that form in veins are different from clots that occur in arteries.

Clots in arteries can lead to:

  • Stroke
  • Transient ischemic attack (TIA)
  • Mini-stroke
  • Heart attack
  • Peripheral arterial clot
  • Gangrene

Clots in veins can cause:

  • Deep vein thrombosis (DVT)
  • Pulmonary embolism (PE)

Deep vein thrombosis occurs most commonly in the leg but can happen anywhere in the body, such as the veins in the arm, abdomen, and pelvis or around the brain. Pulmonary embolism is a potentially life-threatening complication of deep vein thrombosis. 

A pulmonary embolism occurs when a blood clot breaks off from a DVT and travels through the bloodstream to the lung. Occasionally, a pulmonary embolism can form in the lung itself, without any signs of a DVT anywhere else in the body.