Ultrasound‑enhanced, catheter‑directed thrombolysis for pulmonary embolism

Pulmonary embolism (PE) is a condition in which a thrombus, most commonly from a deep vein thrombosis (DVT) in the legs or pelvis, obstructs the pulmonary arterial system. Symptoms of PE depend on the extent of obstruction to the pulmonary arteries: they include chest pain, dyspnoea and haemoptysis. In severe cases PE can result in reduced cardiac output, cardiogenic shock and sudden death. Risk factors for PE include surgery, immobility, trauma, malignancy, acquired or inherited hypercoagulable states, use of oral contraceptives or hormone replacement therapy, pregnancy and dehydration.

A PE without haemodynamic instability is normally treated with low molecular weight heparin (LMWH) or fondaparinux, followed by oral anticoagulants (typically warfarin). The newer factor X inhibitors may be used without preliminary heparin. PEs with haemodynamic instability are sometimes treated with systemic thrombolysis or, occasionally, with endovascular interventions such as catheter‑directed thrombolysis and percutaneous mechanical thrombectomy. Thrombolysis is associated with a risk of haemorrhagic complications including stroke. Surgical thrombectomy may occasionally be performed for patients with a life‑threatening PE.