4.1 Thrombi and Emboli

• What is an abnormal clot in a blood vessel called?

  Thrombus
• What happens to a thrombus when blood continues to flow past it?

  It may break away and become an embolus
• What are freely flowing clots known as?

  Emboli
• Where can emboli that originate in large arteries or the left side of the heart flow to?

  They can plug arteries in the brain or kidneys
• What happens to emboli that originate in the venous system or the right side of the heart?

  They generally flow into the lungs
• What is the condition called when emboli cause blockage in the lungs?

  Pulmonary arterial embolism
• What are the two main causes of thromboembolic conditions?

  Roughened endothelial surface and slow blood flow
• What can cause a roughened endothelial surface in blood vessels?

  Arteriosclerosis, infection, or trauma
• Why does blood often clot when it flows very slowly through blood vessels?

  Small quantities of thrombin are formed
• What is t-PA?

  Genetically engineered tissue plasminogen activator
• How does t-PA help in treating intravascular clots?

  It activates plasminogen to dissolve clots
• When is t-PA most effective in treating a thrombus?

  Within the first hour after occlusion
• What can happen if t-PA is used within the first hour after thrombotic occlusion of a coronary artery?

  The heart is often spared serious damage