Why do mechanical valve patients require warfarin?

• A. Prevent clot formation on the valve
• B. Lower cholesterol
• C. Treat infection
• D. Reduce blood pressure

Answer: (B)

Mechanical heart valves are highly prone to forming clots because the artificial surface and disturbed blood flow promote clotting. If a clot develops on the valve, it can grow and then break off, traveling to the brain or other organs and causing serious embolic events like a stroke. Warfarin is used long-term to prevent this by thinning the blood through inhibition of vitamin K–dependent clotting factors, reducing the risk of valve thrombosis and systemic embolism. This anticoagulation is tailored with an INR target based on the valve type and patient factors. The other options don’t address this specific risk: lowering cholesterol doesn’t prevent valve-related clotting, treating infection is done with antibiotics, and reducing blood pressure is managed with antihypertensives.