The aim of vena cava interruption is to mechanically prevent venous clots from reaching the pulmonary circulation.
A variety of filtering devices can be sited in the inferior vena cava in order to trap thrombus from pelvic and lower limb origins.
They are particularly indicated in patients who have a contraindication to anticoagulation or who have ongoing pulmonary embolism despite full anticoagulation.
The filter is inserted percutaneously with only local anaesthesia via jugular or femoral routes. The filters are commonly sited below the renal vein.
Even with a filter, there is a 5% risk of recurrent pulmonary embolus. Similarly, the complication of leg swelling can occur. Hence, anticoagulation is continued for several months.
NICE suggest that (1):
- do not offer an inferior vena caval (IVC) filter to people with proximal DVT or PE unless:
- it is part of a prospective clinical study or
- anticoagulation is contraindicated or a PE has occurred during anticoagulation treatment
- offer temporary inferior vena caval filters to patients with proximal DVT or PE who cannot have anticoagulation treatment, and remove the inferior vena caval filter when the patient becomes eligible for anticoagulation treatment
- consider inferior vena caval filters for patients with recurrent proximal DVT or PE despite adequate anticoagulation treatment only after considering alternative treatments such as: check adherence to anticoagulation treatment, address other sources of hypercoagulability, increase the dose of anticoagulant or change to an anticoagulant with a different mode of action
- ensure that a strategy for removing the inferior vena caval filter at the earliest possible opportunity is planned and documented when the filter is placed, and that the strategy is reviewed regularly.
Possible complications include (2):
- access site thrombosis
- deep venous thrombosis
- filter migration/embolization
- filter misplacement (outside target zone)
- filter strut fracture
- guidewire entrapment
- IVC thrombosis
- IVC penetration
- pulmonary embolism
- inability to remove retrievable filter