What reverses heparin anticoagulation after CABG?

• A. Vitamin K
• B. Fresh frozen plasma
• C. Protamine sulfate
• D. Aminocaproic acid

Answer: (C)

Protamine sulfate is used to reverse heparin after CABG. Heparin blocks clot formation during surgery, and once CPB is done you need to neutralize it to allow normal coagulation. Protamine sulfate binds to heparin, forming a stable complex that inactivates its anticoagulant effect, effectively restoring the blood’s ability to clot.

In practice, the dose is guided by the amount of heparin given (often ~1 mg of protamine per 100 units of heparin) and is adjusted based on monitoring of coagulation tests (like ACT or heparin concentration). It’s important to administer slowly to minimize risk of hypotension or allergic reactions and to avoid overshoot, which can paradoxically worsen bleeding or cause other complications.

Vitamin K reverses warfarin, not heparin, so it won’t reverse heparin’s effect. Fresh frozen plasma provides clotting factors but does not inactivate heparin, so it helps only if there is concurrent factor deficiency or coagulopathy. Aminocaproic acid is an antifibrinolytic that helps stabilize clots but does not neutralize heparin’s anticoagulant action.