What is the purpose of heparin during left heart catheterization?

• A. To prevent clot formation during catheter manipulation.
• B. To dissolve clots after they form.
• C. To constrict coronary arteries.
• D. To numb the area.

Answer: (A)

During left heart catheterization, blood comes into contact with catheters and devices, which can promote clot formation. Heparin acts as an anticoagulant by boosting antithrombin III, which inhibits thrombin and factor Xa in the coagulation cascade. This prevents new clots from forming on the catheters and in the heart during the procedure, reducing the risk of thromboembolism and keeping the imaging clearer. It does not dissolve clots once they form (that would be a thrombolytic), and it is not a vasoconstrictor or a numbing agent. So the main purpose is to prevent clot formation during catheter manipulation.