What should the nurse educate the client about regarding anticoagulation therapy after a mechanical valve replacement?

Mechanical valves possess a non-biological, thrombogenic surface that triggers the coagulation cascade, leading to a high risk of valve thrombosis and systemic embolism. Lifelong management with warfarin is mandatory to maintain a specific International Normalized Ratio (INR) range, requiring diligent patient monitoring and dietary consistency. A. This statement is the opposite of clinical reality. Biologic (tissue) valves have a lower thrombogenic risk and typically do not require lifelong anticoagulation. Mechanical valves, however, are made of pyrolytic carbon or metal and will always require lifelong pharmacological anticoagulation to prevent catastrophic clot formation. B. Warfarin therapy carries a high risk of hemorrhage. Patients must be educated to report signs of bleeding, such as hematuria, epistaxis, or melena. Furthermore, they must understand that frequent blood tests (INR monitoring) are essential to ensure the dose remains within a safe and therapeutic range. C. Anticoagulation therapy for a mechanical valve must never be discontinued. If the therapy is stopped, the risk of a blood clot forming on the valve and causing a stroke or valve failure is extremely high. "Feeling well" is not an indicator of the blood’s current therapeutic clotting status. D. Vitamin K is the physiological antagonist (antidote) to warfarin. While patients do not need to avoid vitamin K entirely, they must be educated to keep their intake of vitamin K-rich foods (like leafy greens) consistent. Suddenly increasing vitamin K intake will lower the INR and increase the risk of clotting.