Venous thromboembolism: the intricacies

Venous thromboembolism (VTE) has been a subject of great interest of late. Since Rudolph Virchow described the famous Virchow's triad in 1856, there have been rapid strides in the understanding of the pathogenesis and factors responsible for it. Discovery of various thrombophilic factors, both primary and acquired, in the last 40 years has revolutionized prognostication and management of this potentially life-threatening condition due to its associated complication of pulmonary thromboembolism. Detailed genetic mapping and linkage analyses have been underlining the fact that VTE is a multifactorial disorder and a complex one. There are many gene-gene and gene-environment interactions that alter and magnify the clinical picture in this disorder. Point in case is pregnancy, where the risk of VTE is 100-150 times increased in the presence of Factor V Leiden, prothrombin mutation (Prothrombin 20210A) and antithrombin deficiency. Risk of VTE associated with long-haul air flight has now been well recognized. Thrombotic events associated with antiphospholipid syndrome (APS) are 70% venous and 30% arterial. Deep venous thrombosis and pulmonary embolism are the most common venous events, though unusual cases of catastrophes due to central vein thrombosis like renal vein thrombosis and Budd-Chiari syndrome (catastrophic APS) may occur.