A pulmonary embolism (PE) is when a pulmonary artery is obstructed by an embolus (usually a blood clot) that travels to the lungs from deep veins in the leg or pelvis. PE often causes shortness of breath, chest pain and cough. The symptoms and severity vary from no symptoms to cardiovascular collapse and death.
A high-risk PE (also known as massive PE) is defined by sustained systemic hypotension or shock. An intermediate-risk PE (also known as submassive PE) involves right ventricular dysfunction or myocardial injury without major haemodynamic compromise. High‑risk PE accounts for less than 10% of acute PE cases and is a medical emergency with a high mortality rate.
The first-line treatment for PE is systemic or oral anticoagulants. For high- or intermediate-risk PE with haemodynamic compromise, systemic thrombolysis may be used or, rarely, open surgical embolectomy. Catheter-directed therapies may also be used, including catheter-directed thrombolysis and percutaneous thrombectomy. Catheter-directed therapies are usually used if someone has a high-risk PE and they cannot have surgery, or when systemic thrombolysis is contraindicated or has failed.
In this endovascular procedure, a catheter is inserted percutaneously into the peripheral vasculature (usually by a common femoral vein) and advanced through the right side of the heart into the pulmonary arteries under image guidance. This procedure is usually done by interventional radiologists and interventional cardiologists. It is usually done using local anaesthesia with or without sedation.
There are several thrombectomy devices available with some variation in their mechanism of action. The thrombus may be fragmented before removal or not. There are several methods by which the thrombus can be removed: vacuum suction, aspiration with a syringe, mechanical removal with a clot removal device, or a combination of methods. It is a minimally invasive procedure that may be used alone or in combination with other treatment options for PE.
The aim of the procedure is to rapidly remove the obstruction and restore pulmonary circulation, reducing right ventricular strain, while avoiding the bleeding risks associated with thrombolysis.