IVC Filter Device Basics

What Is An IVC Filter?

Inferior vena cava (IVC) filters are small, cage-like medical devices inserted into the inferior vena cava - the main vein returning blood to the heart from the lower body and legs. IVC filters catch blood clots before they can travel to the lungs and cause a pulmonary embolism.

Pulmonary embolism is a potentially fatal condition where a blood clot blocks an artery in the lungs. IVC filters offer protection against pulmonary embolism for patients at high risk of blood clots, especially those who cannot take blood-thinning medications.

IVC filters come in permanent and temporary/retrievable types. Temporary IVC filters are removed once the risk of pulmonary embolism subsides. Permanent filters remain in the body permanently to provide ongoing protection.

IVC filters are implanted through a minimally invasive procedure, often done under light sedation or local anesthetic. A thin tube called a catheter is inserted through a vein in the neck or groin and guided to the IVC. The filter is then deployed to capture blood clots.

IVC Filter Types

There are two main types of IVC filters: permanent and retrievable.

Permanent IVC filters stay in the blood vessel permanently, continuously filtering blood clots to prevent embolization and achieve lifelong protection.

In contrast, retrievable IVC filters are temporary implants to address short-term risks. Once the risk of embolization subsides in a patient, they can be removed through an interventional procedure.

Compared to permanent filters, advantages of retrievable IVC filters include reduced risks of long-term complications from permanent implantation; avoidance of lifelong anticoagulant therapy; and complete removal when thromboembolic risks are eliminated.

Our company specializes in developing and manufacturing safe and effective retrievable IVC filters. The ZYLOX OctoPlus™ Vena Cava Filter is a nitinol laser one-piece cutting and molding that provides excellent immediate vessel wall fixation to the vena cava and superior self-balancing capabilities for efficient long-term thrombus filtration and further clinical benefits.

What is IVC Filter Used For?

IVC filters are mainly used for patients at high risk of pulmonary embolism (PE), but for whom anticoagulation therapy is contraindicated or ineffective.

Typical conditions where IVC filters are recommended include:

- Patients diagnosed with deep vein thrombosis (DVT) or PE who cannot tolerate anticoagulation therapy due to high bleeding risks. IVC filters prevent migration of lower extremity blood clots to the lungs.

- Patients with recurrent PE despite adequate anticoagulation treatment. IVC filters provide added protection against clot migration and PE.

- Patients undergoing high-risk surgeries prone to clot formation, such as hip or knee replacement, trauma surgery, etc. IVC filters serve as short-term prophylaxis when anticoagulants need to be discontinued pre- and post-operatively.

- Cancer patients with elevated DVT/PE risks. IVC filters provide thromboprophylaxis when anticancer therapy raises bleeding risks.

IVC Filter Placement Location & IVC Filter Insertion Procedure

IVC Filter Placement

IVC filters are typically placed in the inferior vena cava, which is the main venous channel for deoxygenated blood returning to the heart's right atrium. Placing a filter in the IVC can capture blood clots dislodging from the lower extremity veins, preventing them from reaching the pulmonary arteries and causing a pulmonary embolism. Specific placement positions include:

- Inferior vena cava below the renal veins - This is the most common placement site.

- Junction of iliac vein and inferior vena cava - The filter may be placed here if IVC thrombosis is present.

- Above existing IVC thrombus - The filter can be placed directly above if the clot cannot be removed.

Formal IVC Filter Placement Procedure

1. Access the right internal jugular vein, insert guidewire and introducer sheath under X-ray guidance.

2. Advance a dilation catheter over the guidewire to dilate the insertion site.

3. Advance the delivery system over the guidewire, accurately position and deploy the filter from the system.

4. Remove delivery catheter, confirm filter position.

5. Apply pressure to puncture site for hemostasis. The entire insertion takes about 20-30 minutes.

6. Conduct periodic CT scans for follow-up of filter status. Determine retrieval timing per clinical needs.

The insertion is a minimally invasive procedure. Patients typically stay in the hospital for 24-hour observation after placement. 

How Is An IVC Filter Removed?

IVC Filter Removal Procedure

The IVC filter is designed to be retrieved after the risk of pulmonary embolism subsides, which is usually in a timeframe of 3-6 months after placement. The retrieval procedure involves the following steps:

1. Access the internal jugular vein under ultrasound guidance and insert a catheter system.

2. Advance the system over a guidewire to the filter location, confirmed by imaging.

3. Engage the snare retrieval kit of the retrieval system to the filter hooks.

4. Collapse the filter into the sheath and remove the system.

5. Apply pressure to the puncture site for hemostasis.

The retrieval procedure usually takes about 30-45 minutes. Most patients can be discharged on the same day. Retrieval rates have been low historically due to prolonged implantation, but have improved with increased awareness. Filters placed for extended periods can get endothelized or even perforate the IVC in rare cases. Imaging follow-up is important to monitor complications. Patients on anticoagulation therapy should stop medications prior to retrieval surgery. 

What to Expect After IVC Filter Placement & Removal

Post-Procedure Care after IVC Filter Placement/Retrieval

After placement or retrieval of an inferior vena cava (IVC) filter, patients will need to follow certain post-procedure instructions and watch for potential complications:

- Rest: Patients will need to avoid strenuous activity for 24-48 hours after the procedure. The access site should be kept clean and dry.

- Medications: Patients may be prescribed medications for pain management. Anticoagulants are typically stopped before procedures and restarted afterwards.

- Follow-up: Imaging follow-up is important to check filter position and watch for complications like migration or perforation.

- Complications: Potential risks include puncture site bleeding/bruising, filter movement, fracture, perforation, and thrombosis. Symptoms like pain or swelling should be reported promptly.

- Retrieval: IVC filters are meant to be temporary so retrieval is recommended once PE risk subsides, usually within 3-6 months. Delayed retrieval has risks.

- Activity: Patients can generally return to normal activity within a few days but should avoid lifting heavy objects for 1-2 weeks.

Close monitoring and follow-up care is important after IVC filter procedures. Patients should understand the post-procedure instructions and risks and report any concerning symptoms to their doctor.