Venous thromboembolism (VTE) occurs in about one in 1000 people each year in developed countries [1, 2]. This disorder commonly occurs as deep vein thrombosis (DVT), when a blood clot develops within a deep vein in the body, usually in the leg. If left untreated, the DVT could embolise therefore leading to a pulmonary embolism. [50].

Epidemiological studies show that VTE is particularly associated with hospitalisation [3]. VTE is a significant cause of death and serious illness. Mortality from VTE can be as high as 21.6% at 1 year [3]. Patients who have had an episode of VTE have a high risk of subsequent VTE. The risk of PTS and CTPH is increased with recurrent DVT and PE, respectively [3].

A good understanding of the epidemiology and risk factors of VTE are important to ensure that healthcare professionals can identify patients at risk and administer appropriate VTE prophylaxis to prevent this disorder and its long-term consequences.

Figure: contrast venogram of the calf, showing a single deep vein thrombosis, 5–10 cm long, in a patient immobilised because of an acute medical illness.