Which of the following is NOT a component of Virchow's Triad?

• A. Arterial injury
• B. Venous stasis
• C. Endothelial injury
• D. Hypercoagulable state

Answer: (A)

Virchow's triad describes three conditions that predispose to venous thrombosis: injury to the endothelium, venous stasis, and a hypercoagulable state. Endothelial injury exposes subendothelial collagen and tissue factor, triggering the coagulation cascade and platelet adhesion. Venous stasis slows the washout of activated clotting factors and allows them to accumulate, promoting clot formation. A hypercoagulable state—whether inherited (like Factor V Leiden) or acquired (such as cancer, pregnancy, or estrogen use)—increases the tendency to clot. Arterial injury, while relevant to arterial thrombosis, is not part of Virchow's triad, which targets venous thrombus formation; arterial thrombi are more driven by platelet aggregation under high flow. So the option describing arterial injury is the one not component of the triad.