Virchow's triad

Overview
Virchow's triad encompasses three broad categories of factors that are thought to contribute to venous thrombosis:


 * 1) Alterations in blood flow (stasis)
 * 2) Injury to the vascular endothelium
 * 3) Alterations in the constitution of blood (hypercoagulability)

The origin of the term "Virchow's triad" is of historical interest. Rudolf Virchow elucidated the etiology of pulmonary thromboembolism, whereby thrombi occurring within the veins -- particularly those of the extremities -- become dislodged and migrate to the pulmonary vasculature. In detailing the pathophysiology surrounding pulmonary embolism, Virchow alluded to many of the factors known to contribute to venous thrombosis. While these factors had already been previously established in the medical literature by others, for unclear reasons they ultimately became known as Virchow's triad.

Thus, the elements comprising Virchow's triad were neither proposed by Virchow, nor did he ever suggest a triad to describe the pathogenesis of venous thrombosis. In fact, it was decades following Virchow's death before a consensus was reached proposing that thrombosis is the result of alterations in blood flow, vascular endothelial injury, or alterations in the constitution of the blood. Moreover, the eponym Virchow's triad did not emerge in the literature until almost 150 years after his original work.

Its nebulous origins notwithstanding, Virchow's triad remains a useful concept for clinicians and pathologists alike in understanding the contributors to venous, and perhaps arterial, thrombosis.

