Virchowtriade

Virchowtriade, also known as Virchow's triad, is a foundational concept in thrombosis describing three broad factors that predispose to clot formation: abnormalities of blood flow, hypercoagulability, and endothelial injury. The triad, proposed by Rudolf Virchow in the 19th century, emphasizes that thrombosis results from the interaction of these elements rather than a single cause.

Abnormalities of blood flow include stasis or turbulence that disrupt normal laminar flow. Venous thrombosis is particularly associated with venous stasis from immobility, congestive heart failure, or varicose veins, as well as surgical procedures. Arterial thrombosis can involve turbulent flow around a ruptured atherosclerotic plaque, contributing to clot formation.

Hypercoagulability encompasses inherited and acquired prothrombotic states. Inherited factors include thrombophilias such as factor V Leiden, prothrombin gene G20210A, and deficiencies of natural anticoagulants (antithrombin, protein C, protein S). Acquired causes include cancer, pregnancy, estrogen therapy, obesity, smoking, antiphospholipid syndrome, and inflammatory or infectious illnesses.

Endothelial injury refers to damage to the vascular endothelium, which promotes coagulation through exposure of subendothelial tissue factor and collagen, and release of procoagulant mediators. This can occur with trauma, surgery, intravascular instrumentation, infection, or toxins, and it often initiates platelet activation and clot propagation.

Together, the Virchowtriade framework aids understanding of the pathogenesis of both venous and arterial thrombosis and informs preventive strategies and risk assessment in clinical practice.