Venous thromboembolism (VTE) is an umbrella term covering deep vein thrombosis (DVT), where a clot forms in a deep vein most commonly in the leg or pelvis, and pulmonary embolism (PE), where part of that clot breaks away and lodges in the pulmonary arteries. The two are manifestations of the same disease process and are managed as a single clinical entity.
Risk arises from the three elements of Virchow's triad: reduced blood flow, vessel wall injury and increased blood coagulability. In practice that translates into recognisable risk factors including immobility, recent surgery (especially major orthopaedic procedures), active cancer, pregnancy and the postnatal period, oestrogen-containing contraception or hormone therapy, obesity, dehydration, older age and inherited thrombophilias.
DVT typically presents with unilateral leg pain, swelling, warmth and redness, while PE may cause pleuritic chest pain, breathlessness, haemoptysis, tachycardia or, in massive cases, collapse. Because symptoms overlap with many other conditions, structured pathways are used. Wells scores stratify probability, D-dimer testing helps exclude VTE in low probability cases, and imaging with compression ultrasound or CT pulmonary angiography confirms the diagnosis.
Anticoagulation is the mainstay, most often with a direct oral anticoagulant, continued for at least three months and longer where the event was unprovoked or the underlying risk persists. Haemodynamically unstable PE may require thrombolysis or embolectomy. Cancer-associated thrombosis is managed with particular care because both recurrence and bleeding risks are elevated.
Hospital-acquired VTE is a major preventable cause of death, and every adult admitted to hospital in England is expected to receive a documented VTE risk assessment. Prophylaxis combines mechanical measures such as intermittent pneumatic compression and anti-embolism stockings with pharmacological prophylaxis, usually low molecular weight heparin, where the thrombotic risk outweighs the bleeding risk. Compliance with risk assessment is a nationally reported quality metric.
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