A patient taking aspirin may show increased postoperative bleeding due to which effect?

Aspirin acts primarily by irreversibly inhibiting the enzyme cyclooxygenase (COX), which plays a crucial role in the production of thromboxane A2. Thromboxane A2 is a potent promoter of platelet aggregation and vasoconstriction. By inhibiting its synthesis, aspirin reduces the ability of platelets to clump together and form a clot effectively. This reduction in platelet aggregation can lead to increased bleeding, especially after surgical procedures where hemostasis is vital.

Understanding this process is essential for managing patients on aspirin in the context of surgical procedures, as they may require special considerations to minimize the risk of postoperative bleeding. This mechanism directly links aspirin usage to the increased bleeding risk due to its effect on platelet functions.