Inferior Vena Cava Filters

1

What is an inferior vena cava (IVC) filter?

An IVC filter is a device inserted percutaneously into the IVC designed to prevent pulmonary emboli (PE) originating from lower extremity deep vein thrombosis (DVT) and to maintain caval patency.

2

What are some common indications for IVC filter placement?

For patients with lower extremity DVT, accepted indications include:

• A contraindication to anticoagulation.

• Recurrent thromboembolic disease despite adequate anticoagulation.

• Significant bleeding complication while undergoing anticoagulation.

• Inability to achieve anticoagulation.

3

List relative indications for IVC filter placement.

• Thromboembolic disease with limited cardiopulmonary reserve.

• Poor compliance with anticoagulation therapy.

• Chronic PE with pulmonary hypertension.

• Prophylaxis in the setting of prolonged immobilization.

• Large clot burden or free-floating pelvic/IVC thrombus.

4

What is a prophylactic IVC filter?

A prophylactic IVC filter is placed in patients who are at an increased risk for, but do not currently have, DVT or PE. These filters are most commonly placed in patients who face prolonged immobilization. This population primarily consists of trauma patients with long bone or pelvic fractures and neurosurgical patients with transient or permanent motor deficits. Prophylactic filters may also be placed in patients with DVT risk factors before having surgery.

5

What is Virchow's triad?

Virchow's triad is a basis for understanding the factors that contribute to thrombosis, including:

• A hypercoagulable state, such as caused by malignancy, nephrotic syndrome, or oral contraceptives.

• Vascular stasis resulting from shock, heart failure, venous obstruction, extrinsic compression, or other causes.

• Vascular injury secondary to various causes, such as trauma, inflammation, surgery, or central lines.

6

What are absolute contraindications to IVC filter placement?

Although rare, absolute contraindications include a lack of venous access; complete thrombosis of the IVC; or a severe, uncorrectable coagulopathy.

7

What are relative contraindications to IVC filter placement?

The decision to place a permanent medical device should be made on a case-by-case basis and only after careful deliberation of the patient's history. One relative contraindication to filter placement is septic emboli or active bacteremia because of the theoretic risk of infectious seeding of the filter. IVC filters are not routinely placed in adolescents or pregnant women. A severe hypercoagulable state or a history of IVC thrombus may preclude filter placement because of the risk of complete IVC thrombosis.

8

How many PE originate from the lower extremities?

Of PE, 75% to 90% originate from the lower extremities. The remainder originate from the right atrium and upper extremities and likely account for some of the cases of recurrent PE after IVC filter placement.