IVC Filter Placement

The IVC filter is like an umbrella-shaped device which is placed in the inferior vena cava. It is a special device made up of metal which is placed either through the veins of your leg or through the neck veins into the inferior vena cava. Multiple shapes and types of inferior vena cava filters are available in the market. Consider the IVC filter to be a filtration mechanism wherein large clots from the deep veins of the leg are prevented from migrating to the heart and arteries of the lung. These clots get entrapped within the twines and prongs of the filter preventing upward migration. Therefore, an IVC filter is placed to prevent pulmonary thromboembolism.

An IVC filter does not have to be placed in all cases of DVT and pulmonary embolism. 

The conventional and standard protocol treatment option for both DVT and pulmonary embolism is only medical management in the form of anticoagulation. Anticoagulants are drugs which are given to prevent further clot propagation and clot migration. In most cases only injectable anticoagulants followed by oral anticoagulants is the standard treatment for both DVT and pulmonary embolism. However, when the patient is not responding to anticoagulation or when there is massive DVT involving the complete lower limb venous system, newer treatment options like mechanical and pharmacomechanical thrombectomy to suck out the entire thrombus can be warranted.

In cases of pulmonary thromboembolism, despite medical management the patient continues to have low saturation or low blood pressure, in these cases the clot from the pulmonary arteries can either be sucked out using special devices (called thrombectomy) or special drugs can be placed right within the thrombus through the special catheters called catheter directed thrombolysis (CDT).

Details of these procedures and whether you are a candidate for these procedures is dependent on case to case basis.

It has significantly reduced over the past few years due to the development of newer drugs and agents. However certain important indications of IVC filter are as follows:

• When blood thinning drugs/anticoagulants cannot be given due to any contra-indication (for example recent surgery).
• When blood thinning drugs/anticoagulants cannot be given since the patient is bleeding due to the blood thinning agents – eg bleeding in urine or stools.
• When the patient has to undergo another surgery, for which the blood thinning agents need to be stopped.
• When the patient has a repeat or recurrent pulmonary thromboembolism despite being on anticoagulants.
• In these cases, to prevent further pulmonary embolism, that is to prevent further clot migration from the deep veins into the pulmonary artery, an IVC filter is required.

Another new indication of IVC filter placement is prior to mechanical thrombectomy for massive iliofemoral deep venous thrombosis cases. In certain patients with massive DVT when the clot needs to be sucked out, an IVC filter is temporarily placed so that during the surgery no clot migrates into the lungs. 

• The IVC filter is placed under local anaesthesia in most cases.
• This filter can be placed either through the veins of your groin or through the neck veins.
• The area is first clean and shaved. Following this, local anaesthesia is infiltrated to prevent any local pain and to numb the area.
• Under ultrasound guidance, a needle is placed inside the vein following which over the guide wire a small tube called sheath is placed.
• Through this sheath the IVC filter is inserted inside the body. The IVC filter is generally placed at the level below the level of renal veins.
• This is done to prevent any renal vein clotting.

When can the IVC filter be removed?

Newly available IVC filters are all retrievable. The disadvantage of an IVC filter is that the patient needs to be on long-term or lifelong anticoagulation. Therefore, it is always advisable that the IVC filter be removed. However, depending on the indication of filter placement and on case to case basis, the timing of IVC filter removal needs to be decided in joint conjunction with your primary treating doctor.

How is the IVC filter removed?

Just like placement, the retrieval of the IVC filter can also be done under local anaesthesia. However, for difficult cases, sedation may be required. Most cases are done through the veins of your neck. However, in complex cases a combined groin as well as neck access may be used. Filters that are generally placed within one month can easily be removed without any difficulty. However, long-standing filters which are placed more than 1 to 3 months prior, pose a challenge. A prior CT scan may be required to localize the exact location of the prongs of the filter and the presence of any associated clot. 

Depending on the complexity and the timing of filter placement, sometimes an IVC filter removal may be extremely difficult requiring multiple operators, refined techniques and special devices like forceps and balloons.