An
inferior vena cava filter, also
IVC filter a type of vascular filter, is a medical device that is implanted into the
inferior vena cavaThe inferior vena cava is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart....
to prevent fatal
pulmonary emboliPulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...
(PEs).
IVC filters are used in case of
contraindicationIn medicine, a contraindication is a condition or factor that increases the risks involved in using a particular drug, carrying out a medical procedure, or engaging in a particular activity....
to anticoagulation, failure of anticoagulation or complication to anticoagulation in patients who have a venous thromboembolic disease or in prophylactic use for patients with a high risk of pulmonary embolism.
IVC filters are placed endovascularly, meaning that they are inserted via the blood vessels.
An
inferior vena cava filter, also
IVC filter a type of vascular filter, is a medical device that is implanted into the
inferior vena cavaThe inferior vena cava is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart....
to prevent fatal
pulmonary emboliPulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...
(PEs).
IVC filters are used in case of
contraindicationIn medicine, a contraindication is a condition or factor that increases the risks involved in using a particular drug, carrying out a medical procedure, or engaging in a particular activity....
to anticoagulation, failure of anticoagulation or complication to anticoagulation in patients who have a venous thromboembolic disease or in prophylactic use for patients with a high risk of pulmonary embolism.
Placement
IVC filters are placed endovascularly, meaning that they are inserted via the blood vessels. Historically, IVC filters were placed surgically, but as designs changed they could be placed via the groin through a thin tube or catheter. With modern filters which can be compressed into much thinner
catheterIn medicine a catheter is a tube that can be inserted into a body cavity, duct or vessel. Catheters thereby allow drainage, injection of fluids or access by surgical instruments. The process of inserting a catheter is catheterization. In most uses a catheter is a thin, flexible tube , although...
s, however, access to the venous system can be obtained either via the
femoral veinIn the human body, the femoral vein is a blood vessel that accompanies the femoral artery in the femoral sheath. It begins at the adductor canal and is a continuation of the popliteal vein...
(the large vein in the groin),the
internal jugular veinThe two internal jugular veins collect the blood from the brain, the superficial parts of the face, and the neck.-Path:The inferior petrosal sinus and the sigmoid sinus join to form each internal jugular vein, and begins in the posterior compartment of the jugular foramen, at the base of the...
(the large vein in the neck.) or via the arm veins with one design. Choice of route depends mainly on the amount and location of blood clot within the venous system. To place the filter, a catheter is guided into the IVC using fluoroscopic guidance, then the filter is pushed through the catheter and deployed into the desired location, usually just below the junction of the IVC and the lowest
renal veinThe renal veins are veins that drain the kidney. They connect the kidney to the inferior vena cava.It is usually singular to each kidney, except in the condition "multiple renal veins".It also divides into 2 divisions upon entering the kidney:...
.
Review of prior cross-sectional imaging or a venogram of the IVC is performed before deploying the filter to assess for potential anatomic variations, thrombi within the IVC, or areas of stenoses, as well as to estimate the diameter of the IVC. Rarely, ultrasound-guided placement is preferred in the setting of contrast allergy, renal insufficiency, and when patient immobility is desired. The size of the IVC may affect which filter is deployed, as some (such as the Birds Nest) are approved to accommodate larger cavas. There are situations where the filter is placed above the renal veins (e.g. pregnant patients or women of childbearing age, renal or gonadal vein thromboses, etc.). Also, if there is duplication of the IVC, the filter is placed above the confluence of the two IVCs or a filter can be placed within each IVC.
Indications for use
Most filters are placed for the following reasons.
- Failure of anticoagulation; eg development of deep vein thrombosis (DVT) or pulmonary emboli (PE) despite adequate anticoagulation.
- Contraindications to anticoagulation; eg a patient at risk of PE who has another condition that puts them at risk of bleeding, such as a recent bleed into the brain, or a patient about to undergo major surgery
- Large clots in the vena cava or iliac veins
- Patients at high risk of having a PE
Retrieval
Most IVC filters are permanent, but some filters are now available that are "retrievable." Retrievable filters are fitted with some sort of device (that varies from model to model) that allows them to be pulled back into a catheter (technically a "sheath") and removed from the body, often through the
Jugular veinThe jugular veins are veins that bring deoxygenated blood from the head back to the heart via the superior vena cava.-Internal and external:There are two sets of jugular veins: external and internal....
. Previously, filters that had been in the IVC for less than three weeks were considered suitable to attempt retrieval, as filters that have been in place longer might have been overgrown by cells from the IVC wall and there was an increased risk of IVC injury if the filter is dislodged. Newer designs, and developments in techniques mean that some filters can now be left in for prolonged periods and retrievals after a year are now being reported. This would include the ALN, Option, Tulip and Celect filters.
IVC filter brands
- B Braun Tempofilter IVC filter (retrievable)
- B Braun VenaTech LGM IVC filter (no longer sold)
- B Braun VenaTech LP IVC filter
- Bard G2 IVC (retrievable, unlimited indwell time)
- Bard Recovery IVC filter (retrievable) (no longer sold)
- Bard Simon Nitinol IVC filter
- Boston Greenfield IVC filter
- Cook Birds Nest IVC filter
- Cook Celect IVC filter (retrievable)
- Cook Gunther Tulip IVC filter (retrievable)
- Cook Gianturco-Roehm Bird's Nest IVC Filter (not retrievable)
- Cordis OptEase IVC filter (retrievable, 23 day indwell time)
- Cordis TrapEase IVC filter
- Mobin-Uddin Umbrella IVC filter (no longer sold)
- ALN IVC filter (retrievable)
- Rex Medical Option IVC filter (retrievable) (in clinical trials)
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