Final answer:
Long-term anticoagulation is indeed necessary after a mechanical valve replacement due to the increased risk of thromboembolic events such as strokes.
Step-by-step explanation:
True, long-term anticoagulation is necessary after mechanical valve replacement. Mechanical heart valves are associated with an increased risk of thromboembolic events, such as strokes and blood clots, due to their artificial nature and the body’s response to a foreign object. To prevent these risks, anticoagulation therapy, typically with medications like warfarin, is required to thin the blood and reduce the formation of clots. Patients with mechanical heart valves typically need to take anticoagulants for the rest of their lives and must have their blood's clotting tendency regularly monitored to ensure the dosage remains effective without causing excessive bleeding.