Inferior vena cava filter

Inferior Vena Cava Filter

The inferior vena cava filter (IVC filter) is a type of vascular filter that is implanted by interventional radiologists or vascular surgeons into the inferior vena cava to prevent pulmonary embolism (PE). Pulmonary embolism is a blockage in one of the pulmonary arteries in the lungs usually caused by blood clots that travel to the lungs from the legs or, rarely, other parts of the body (deep vein thrombosis). Because the inferior vena cava is the main vessel returning blood from the lower half of the body to the heart, placing a filter in this location can catch emboli before they enter the lungs.

Indications

The primary indication for the placement of an IVC filter is to provide protection against pulmonary embolism in patients who are at high risk for such events and in whom anticoagulant therapy is contraindicated, has failed, or is not tolerated. This includes patients with:

• Recurrent PE despite adequate anticoagulation
• Contraindication to anticoagulation (e.g., recent surgery, bleeding disorders)
• Complications from anticoagulation
• Massive PE with residual deep vein thrombosis in patients who cannot receive anticoagulation

Types of Filters

There are several types of IVC filters, including permanent and retrievable filters. Retrievable filters are designed to be removed once the risk of PE has subsided. However, not all retrievable filters are removed, and the decision to remove a filter is based on the patient's risk of PE versus the risk of having the filter in place.

Procedure

The insertion of an IVC filter is typically performed under local anesthesia and sedation. Using fluoroscopic guidance, the filter is inserted through a catheter that is placed into a vein in the neck or groin and advanced to the inferior vena cava. Once in the correct position, the filter is deployed from the catheter and placed in the inferior vena cava.

Risks and Complications

While the placement of an IVC filter can be life-saving for patients at risk of PE, there are associated risks and complications, including:

• Filter migration
• Filter fracture
• IVC perforation
• Deep vein thrombosis at the insertion site
• Difficulty removing the filter

Follow-up

Patients with an IVC filter require regular follow-up to assess the filter's position, integrity, and the ongoing risk of PE. This may include imaging studies such as duplex ultrasound, CT scan, or MRI.

Conclusion

The use of inferior vena cava filters is a critical intervention in the prevention of pulmonary embolism in patients who cannot be managed with anticoagulation therapy alone. While effective, the decision to place an IVC filter must be carefully considered against the potential risks and complications associated with the device.