Which concept describes the three factors that predispose to venous thromboembolism, including venous stasis, vein injury, and hypercoagulability?

• A. D-dimer Elevation
• B. Antiphospholipid Syndrome
• C. Virchow's Triad
• D. Factor V Leiden

Answer: (C)

Virchow's triad describes the three conditions that predispose to venous thromboembolism: venous stasis, endothelial injury, and hypercoagulability. Venous stasis slows blood flow, which allows clotting factors to accumulate and interact longer with the vein walls—this often happens with prolonged immobility, hospitalization, or long periods of sitting. Endothelial injury refers to damage to the inner lining of the vein from surgery, trauma, or catheters; this injury exposes tissue and promotes platelet adhesion and activation of the coagulation system. Hypercoagulability means the blood has an increased tendency to clot, which can be due to inherited factors (like Factor V Leiden or other thrombophilias) or acquired states (such as cancer, pregnancy, or estrogen therapy).

The other choices relate to parts of the process or specific conditions but do not capture the three-factor framework. D-dimer elevation is a marker of clot breakdown, not a predisposition to clot formation. Antiphospholipid syndrome is a particular prothrombotic disorder, not the general trio of factors. Factor V Leiden is one genetic cause of hypercoagulability, but it represents a single factor rather than the full triad.

That integrated, three-factor concept is what best explains why venous clots form.