6th July 2026

Background

Venous thromboembolism (VTE), occurs when a blood clot forms in a vein. The two main components are deep vein thrombosis and pulmonary embolism. In a deep vein thrombosis (DVT) a thrombus forms in the deep veins of the body, most commonly in the lower limb (legs and pelvis), although it can occur in the upper limbs, cerebral veins, and splanchnic veins as well. This thrombus can break off and embolise, or lodge itself, into a blood vessel downstream. When a thrombus blocks a vessel in the pulmonary arterial tree, this is known as a pulmonary embolism (PE), which can be life-threatening.