Percutaneous mechanical thrombectomy for acute deep vein thrombosis of the leg

Evidence-based recommendations on percutaneous mechanical thrombectomy for acute deep vein thrombosis of the leg in adults. This involves removing the clot through a catheter inserted into the vein.

# Recommendations
Current evidence on the safety of percutaneous mechanical thrombectomy for acute deep vein thrombosis (DVT) of the leg shows there are well-recognised but infrequent complications.
For acute iliofemoral DVT, the evidence on efficacy is limited in quality and quantity, therefore this procedure should only be used with special arrangements for clinical governance, consent, and audit or research. Find out what special arrangements mean on the NICE interventional procedures guidance page.
For distal DVT that does not extend into the common femoral vein, the evidence on efficacy is inconclusive, therefore this procedure should only be used in the context of research. Find out what only in research means on the NICE interventional procedures guidance page.
Clinicians wishing to do percutaneous mechanical thrombectomy for acute iliofemoral DVT should:
Inform the clinical governance leads in their NHS trusts.
Ensure that patients understand the procedure's safety and efficacy, as well as any uncertainties about these. Provide them with clear written information to support shared decision making. In addition, the use of NICE's information for the public is recommended.
Clinicians should enter details of all patients who have the procedure onto the British Society of Interventional Radiology Venous Registry.
Further research should report the patient selection criteria including the site of the clot, symptom severity and age of patients.# The condition, current treatments and procedure

# The condition
Deep vein thrombosis (DVT) is a blood clot that develops within a deep vein, usually in the leg. It can cause pain, swelling, tenderness and red skin but sometimes there are no symptoms. Risk factors for DVT include surgery, immobility, malignancy, hypercoagulability, pregnancy and dehydration.
DVT may lead to complications because the blood flow in the leg is being affected. Chronic venous insufficiency can cause postthrombotic syndrome in the affected leg with pain, swelling, and sometimes chronic ulceration. Raised venous pressure can rarely cause phlegmasia cerulean dolens with oedema of the leg, cyanosis, blistering and ischemia. If the clot becomes dislodged it can travel through the veins to the lungs and cause a pulmonary embolus, which is potentially lifethreatening.

# Current treatments
A DVT is usually treated with anticoagulation. Extensive DVT is sometimes treated with systemic thrombolysis, or by endovascular interventions such as catheterdirected thrombolysis. Thrombolysis is associated with a risk of haemorrhagic complications including stroke. Surgical thrombectomy is an option when a DVT is refractory to thrombolytic therapy, or in people for whom thrombolysis is contraindicated, but it is rarely used.

# The procedure
Percutaneous mechanical thrombectomy for acute DVT of the leg is usually done together with direct infusion of a thrombolytic drug into the thrombus. However, it can be done by itself if thrombolytic drugs are contraindicated. It can also be done before thrombolysis to reduce the size of the clot, or after thrombolysis if the thrombus persists.
The procedure is done using local anaesthesia. Imaging is used to determine the appropriate venous access, which is usually the popliteal or femoral vein. A catheter is advanced through the vein into the thrombus using fluoroscopic guidance. There are a range of mechanical thrombectomy devices that use different principles. The objective is mechanical disruption and aspiration of the thrombus. A temporary inferior vena cava filter may be used during the procedure to reduce the risk of pulmonary embolism from a displaced clot.
Anticoagulant drugs are usually taken for at least 3 months after the procedure and sometimes longer if clinically indicated, to prevent recurrence. Early ambulation and use of compression stockings are advised.
Adjuvant angioplasty or stenting of the vein may be needed if thrombus removal reveals an anatomical lesion that contributed to the formation of the DVT or that increases the risk of recurrence.