Inferior vena cava (IVC) Filters

Deep venous thrombosis (DVT) refers to the formation of a blood clot or "thrombus" in the veins typically of the leg or pelvis. This may occur due to risk factors including:

• Immobility (e.g., long-haul flight)
• Post-surgery
• Pregnancy
• Smoking
• Cancer
• Genetic predisposition

If you develop a DVT, you may have symptoms including leg swelling, pain and discolouration. The DVT in the leg is not life-threatening, however part of it breaks away and travels to the lung, this is called a "Pulmonary Embolus" or "PE" and can be life-threatening.

Typical treatment for DVT and PE is with blood-thinner medications, which help the body to break down the blood clots over time. However, in certain circumstances, an IVC Filter may be recommended. Generally, an IVC Filter is suitable if:

1. You have developed Pulmonary Emboli (PE) despite taking anticoagulation medication
2. You are unable to take the anticoagulation medication (or the full dose) due to a contraindication such as recent surgery, bleeding or pregnancy

In addition to these two categories, there are other circumstances where an IVC Filter may be recommended, including complex trauma injuries where multiple surgeries are required.

An IVC Filter is a small device made from nitinol metal composed of a neck and multiple "legs." The IVC filter is placed in the inferior vena cava (IVC), the main vein channel that connects the legs to the chest and lungs, to catch any DVT fragments that may be travelling or "embolising" towards the lungs via the IVC.

There are many brands and designs of IVC Filter, but in Australia, the common types are:

• Cook Celect
• BD Denali

Modern IVC filters are almost always retrievable and temporary, which means that once the IVC filter is no longer required, it should be removed. It is important that if you have an IVC filter inserted that it is planned for removal, as the longer it remains in place, the more difficult it can be to remove.

1. IVC filter insertion is performed under local anaesthetic and light sedation
2. A small sheath tube is passed into the vein of typically the right groin or neck
3. The sheath is advanced into the IVC, typically below the level of renal veins (kidney)
4. The IVC filter is placed and position confirmed with venography imaging
5. The sheath is removed and pressure placed on the groin to minimise bruising

Standard

1. Standard IVC filter removal is performed under local anaesthetic and light sedation
2. A small sheath tube is passed into the vein of typically the right neck
3. The sheath is advanced into the IVC, and venography imaging performed to confirm the location and configuration of the IVC filter
4. The IVC filter is "snared" or "hooked" and captured inside the sheath
5. The sheath is removed and pressure placed on the neck to minimise bruising

Advanced / Complex

1. Advanced / Complex IVC filter removal is typically performed under general anaesthetic
2. A large sheath tube is passed into the vein of typically the right neck
3. The sheath is advanced into the IVC, and venography imaging performed to confirm the location and configuration of the IVC filter
4. The IVC filter is grasped using a variety of advanced techniques including a wire loop snare or forceps
5. The IVC filter is then captured inside the sheath
6. The sheath is removed and a suture typically placed in the neck to minimise bruising

The overall rate of major complications is low, however the rate is higher if the IVC filter has been in place for a prolonged period of time and advanced / complex retrieval is required. Possible complications include:

• IVC stenosis (narrowing) or occlusion (blockage)
• IVC filter fracture and embolisation
• Failure to retrieve
• Bruising or haematoma

Interventional Radiologists (IRs) are specialty trained in the management of IVC filters, including the pre-procedural assessment, operation and post-procedural care. Experienced Interventional Radiologists (IRs) are able to safely remove almost all IVC filters, regardless of how long it has been in place or the position. If you have had a previous unsuccessful attempt at retrieval, or have been told it cannot be removed, you are welcome to seek consultation with our Specialist Interventional Radiologists as it may actually be safe to remove.

Dr Matthew Lukies

Matthew has performed over 300 IVC filter procedures, including very complex IVC filter retrievals that have been present for over 10 years and unable to be retrieved by other operators. Matthew has specific training in advanced techniques including the use of wire loop snares and endovascular forceps.

If you would like to consult with an Interventional Radiologist about IVC Filter Removal (Retrieval), please send a referral, including:

• Results of imaging tests (e.g., CT scans)
• Past medical history

Public eligible patients can undergo the treatment with no out-of-pocket expense in the public system.