A 62-year-old man with a history of myocardial infarction 2 years ago is on chronic antiplatelet therapy. He is scheduled for elective total knee replacement in 3 weeks. The drug marked **A** in the diagram irreversibly inhibits platelet cyclooxygenase-1, blocking thromboxane A2 synthesis. Because platelets lack a nucleus and cannot regenerate this enzyme, the antiplatelet effect persists for the platelet lifespan. Based on this mechanism, when should this drug be discontinued before elective surgery to minimize perioperative bleeding risk?