Table of Contents
- Blood clot facts
- What are blood clots? What does a blood clot look like?
- What causes blood clots (blood clots in veins or arteries)?
- What causes blood clots (blood clots in the heart, leaking, and other causes)?
- What are the risk factors for blood clots?
- What types of conditions are caused by blood clots (DVT and pulmonary embolism)?
- What types of conditions are caused by blood clots (AFib, atrial thrombosis, and others)?
- What are the symptoms of blood clots?
- How are blood clots diagnosed?
- What tests are used to diagnose blood clots?
- What is the treatment for blood clots?
- What are the complications of blood clots?
- How can blood clots be prevented?
What causes blood clots (blood clots in veins or arteries)?
Blood clots form when there is damage to the lining of a blood vessel, either an artery or a vein. The damage may be obvious, such as a cut or laceration, or may not be visible to the naked eye. Blood also will begin to clot if it stops moving, and becomes stagnant, or in diseases that cause the blood to clot abnormally.
Blood clots in a vein (venous thrombosis) occur when a person becomes immobilized and muscles are not contracting to push blood back to the heart. This stagnant blood begins to form small clots along the walls of the vein. This initial clot can gradually grow to partially or completely occlude or block the vein and prevent blood from returning to the heart.
An analogy to this process is a slow moving river. Over time, weeds and algae start to accumulate along the banks of the river where the water flows more slowly. Gradually, as the weeds start to grow, they begin to invade the center of the river because they can withstand the pressure of the oncoming water flow.
Blood clots in an artery (arterial thrombi) occur by a different mechanism. For those with atherosclerotic disease, plaque deposits form along the lining of the artery and grow, which causes the vessel to narrow. This disease process may cause:
If a plaque ruptures, a blood clot can form at the site of that rupture and can completely or partially occlude the blood flow at that point.