Virchowtrias

Virchowtrias, commonly called Virchow's triad, is a framework describing three broad categories of factors that predispose to thrombosis: endothelial injury, altered blood flow, and hypercoagulability. Formulated by Rudolf Virchow in the 19th century, the triad remains a foundational concept in hematology and vascular medicine for understanding how clots form in arterial and venous systems.

Endothelial injury or dysfunction refers to damage to the lining of blood vessels, which can occur due to surgery, trauma, inflammation, atherosclerosis, or the presence of medical devices. Such injury exposes subendothelial structures and promotes platelet activation and coagulation.

Altered blood flow encompasses stasis, turbulence, and changes in shear stress. Stasis is common with immobility, heart failure, or varicose veins, while turbulence can arise from arterial stenosis or valvular disease. Both conditions favor clot formation by concentrating clotting factors and impairing washout of activated components.

Hypercoagulability describes an increased tendency for blood to clot and includes inherited conditions such as factor V Leiden and prothrombin gene mutations, as well as acquired states like cancer, pregnancy, hormonal therapy, obesity, and inflammatory disorders. These factors tip the balance toward coagulation.

Clinically, the triad guides risk assessment and prevention of thrombotic events, informing strategies such as anticoagulation, compression therapy, mobilization, and management of underlying conditions. Modern understanding recognizes that thrombosis is multifactorial and dynamic, with contributions from platelets, the coagulation cascade, inflammatory processes, and endothelial function beyond the classic three categories. The triad remains a useful starting point for evaluating thrombotic risk.