Inferior Vena Cava Filter (IVC Filter)

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  • IVC filter placement is an interventional radiologic procedure to prevent the propagation of a deep venous thrombus (DVT), or “blood clot” from a vein in your legs or pelvis to your lungs.

 

  • Risk factors for a DVT:
    • Inheriting a blood-clotting disorder
    • Prolonged immobility
    • Injury or surgery
    • Pregnancy
    • Oral contraceptives
    • Obesity
    • Smoking
    • Cancer
    • Family history
    • Age greater than 60

Indications

Accepted:

  • Documented deep venous thrombus (DVT) with one or more of the following:
    • Contraindication to anticoagulation
      • High risk of bleeding, intracranial hemorrhage, recent surgery, allergy
    • Formation or progression of DVT while on therapeutic anticoagulation
    • Inability to maintain therapeutic level of anticoagulation
    • Poor patient compliance with medical management

Relative:

  • Prophylactic in the setting of major trauma, closed head injury, spinal cord injury, multiple long bone fractures, high-risk patients with prolonged immobilization

Contraindications

  • True contraindications are rare
    • IVC too large or too small to safely accommodate filter
    • Confirmed allergy to filter component
    • Inability to gain venous access
    • Total thrombosis of the IVC

Complications

  • Access site thrombosis
  • IVC thrombosis (<30%)
  • IVC perforation (9-24%)
  • Filter migration/embolization
  • Filter fracture 1%
  • Penetration of vena cava wall à adjacent organs, aorta, etc.
  • Other: infection, air embolism, bleeding

Work-up

  • Ultrasound:
    • Most common test. Utilizes sound waves to visualize veins within the lower extremities to assess for a visible thrombus, compressibility of the vein, and evidence of blood flow. A series of ultrasounds may be done to determine whether a blood clot is growing or to check for a new one.
  • D-dimer:
    • This is a blood test which can be performed. A DVT would cause an elevated D-dimer level, although many other derangements can elevate D-dimer. A negative D-dimer is highly specific to rule out a DVT.
  • CT or MRI scans:
    • Either can provide visual images of your veins and might show a thrombus. Often these scans performed for other reasons and incidentally reveal a thrombus. Given the radiation associated with a CT scan, and the high cost associated with MRI, these modalities are not typically first line for DVT detection.

Procedure/Technique:

  • Access to the vena cava: Typically obtained via the internal jugular or common femoral vein.
  • Venogram of the IVC: Performed to define/confirm anatomy and plan deployment location. The most common location for deployment of the IVC filter is below the level of the renal veins, although there are instances which may warrant alternate location, like placing a filter in the suprarenal segment, when there is a clot in the infrarenal segment.

  • Duration: Takes about 30 – 60 minutes depending on the anatomy and technique.
  • Level of risks: Minimal

What is an IVC (inferior vena cava) filter?

An IVC filter is a medical device which is placed within the IVC (Inferior vena cava), with the purpose of “catching” blood clots to prevent them from traveling through your leg veins and into your lungs.

Why do I need an IVC filter?

There are many indications for an IVC filter. Most often they are needed when a blood clot in the legs is present and there is a contraindication to blood thinning medication (recent bleeding, surgery, etc.). Occasionally they are placed when a blood clot develops, despite being on blood thinning medication. There may also be other reasons to have an IVC filter placed more unique to your situation, which can be discussed with your doctor.

How is the filter placed?

Prior to the start of the procedure you may be given some medications to help relax you. A local numbing medication is also injected at the determined access site, usually the neck or groin. During this portion of the procedure you will feel a small poke, followed by a burning sensation, which should dissipate in about 5-10 seconds. After this, access will be obtained into the predetermined vein, under a combination of ultrasound and fluoroscopic guidance. A wire will be passed through the access site. This wire will allow passage and exchange of multiple sheaths, catheters, and medical instruments into the venous system. Prior to deployment of the IVC filter a venogram may be completed to assess anatomy and determine appropriate positioning. The IVC filter deployment system will then be passed through a sheath into the appropriate location and deployed under fluoroscopic guidance to ensure appropriate positioning. Once this is complete, all instruments will be removed and manual pressure will be applied to the venous access site until hemostasis is achieved. A dressing will then be applied.

Who will place the filter?

A doctor who is specialized in interventional radiology will place the filter using the X-ray and ultrasound to guide them.

Will it be painful?

Local anesthetic (Lidocaine) will be used to numb the skin at the access site. This causes a “burning” sensation which subsides in approximately 5-10 seconds. You may experience some pressure during the procedure; however, this is generally not regarded as painful. Overall, patient tolerate the procedure very well.

What are the potential complications?

Overall complication rate with IVC filter placement is very low, less than 1%. Some of the complications include bleeding, infection, filter fracture/migration, and IVC penetration.

What can I expect after the procedure?

IVC filter placement is usually very well tolerated. Patients are monitored for one hour after the completion of the procedure to assess for and immediate complications. The access site in the neck or groin may be a little sore, but soreness should subside.

How long does the filter stay in place?

IVC filters can remain in place as long as needed, or may be removed if there is no longer a need for them.