What is the purpose of anticoagulation during diagnostic coronary angiography?

• A. To prevent thrombus formation during catheter manipulation
• B. To prevent infection
• C. To reduce contrast nephropathy
• D. To dilate vessels

Answer: (A)

Anticoagulation is used to prevent thrombus formation on the catheter and within the coronary arteries during catheter manipulation. Inserting and moving a catheter through the arteries can injure the vessel lining and disturb blood flow, which promotes clotting. An anticoagulant like heparin slows the coagulation cascade, reducing thrombin formation and platelet aggregation, so catheter-related clots and distal emboli are less likely to form and cause myocardial ischemia or stroke during the procedure. This purpose is distinct from infection prevention, nephroprotection, or vasodilation, which rely on sterile technique and antibiotics, hydration and careful contrast use, or vasodilator medications, respectively.