Endovenous Placement of Inferior Vena Caval Filters

Historical Background

Venous interruption for the prevention of pulmonary embolism (PE) was introduced by Homans in 1934. Although his initial description involved ligation of the femoral vein, surgical techniques soon evolved, focusing on interruption at the level of the inferior vena cava (IVC). Complete ligation of the IVC was performed in 1959, but the resulting cardiovascular complications and venous sequelae led to the development of alternative strategies for either temporary interruption or plication. These included temporary ligation of the IVC using absorbable suture, plication of the IVC using interrupted mattress suture, and partially occluding externally applied polytetrafluoroethylene (PTFE) clips (Moretz clip, Adams-DeWeese clip). These techniques required retroperitoneal exposure and general anesthesia, which are distinct disadvantages, particularly in patients who are often ill with significant comorbidities.

The Mobin-Uddin umbrella, introduced in 1967, was the first IVC filter that could be inserted via a transjugular approach under local anesthesia. The apex of this device was oriented inferiorly, and the original design incorporated a solid, fabric membrane with the intent of causing caval thrombosis. Fenestrations were added later, with the purpose of causing delayed thrombosis, supposedly increasing the development of collaterals. However, some patients maintained a patent IVC, and yet they had a low rate of pulmonary embolization. These observations led to significant design advances, such that IVC thrombosis was no longer the desired outcome. The superior design of the Greenfield filter (Boston Scientific, Natick, MA), with its low rate of caval thrombosis, allowed it to rapidly supplant prior filter designs. The Greenfield (and the ensuing iterations) could be placed via a transjugular or transfemoral approach, and it became the standard caval interruption device to which newer filters were compared for the next few decades.

Patient Selection

The accepted and relative indications for placement of an IVC filter are shown in Table 13.1 . Although anticoagulation is the mainstay of therapy in patients with acute deep venous thrombosis (DVT) or PE, it may be contraindicated for several reasons. Active internal bleeding is an absolute contraindication to therapeutic anticoagulation. However, an increased risk of bleeding caused by recent trauma or major surgery (especially neurologic or ocular surgery) more often is a relative contraindication that is subject to clinical judgment. In the era when unfractionated heparin and vitamin-K antagonists were the only available antithrombotic agents, nonhemorrhagic complications of anticoagulation (e.g., heparin-induced thrombocytopenia, warfarin-induced skin necrosis) were more common indications for IVC filter insertion. However, the greater availability of effective antithrombotic alternatives, such as low-molecular-weight heparin, pentasaccharides, direct thrombin inhibitors, and oral factor Xa inhibitors have curtailed the use of unfractionated heparin and warfarin for the treatment of venous thromboembolism (VTE).

TABLE 13.1

Indications for Placement of an Inferior Vena Cava Filter

Common Indications for IVC Filter Placement

Contraindication to anticoagulation in a patient with an acute proximal LE DVT or PE Recurrent VTE despite adequate antithrombotic therapy; recurrence may include significant proximal DVT extension in an ipsilateral LE, development of a new proximal DVT in a contralateral LE, or PE Massive PE with residual LE DVT

Relative Indications for IVC Filter Placement

Patients with PE and significant pulmonary disease (pulmonary hypertension, cor pulmonale) Prophylactic IVC filter placement in a patient at high risk for VTE in whom antithrombotic therapy is contraindicated and in whom adequate diagnostic imaging cannot be performed (e.g., trauma patient with lower extremity injuries) During catheter-directed pharmacomechanical thrombolysis “Free-floating” thrombus in the proximal deep veins of the lower extremities

DVT, Deep venous thrombosis; IVC, inferior vena cava; LE, lower extremity; PE, pulmonary embolism; VTE, venous thromboembolism.

An often-cited indication for IVC filter insertion is “failure of anticoagulation.” Significant proximal DVT extension and PE may occur in up to 4% to 11% of patients who receive anticoagulation for acute lower extremity DVT. Over 70% of these failures occur in the first 3 weeks after initiation of therapy. However, there should be a distinction between patients who are receiving adequate antithrombotic therapy versus those receiving inadequate antithrombotic therapy. Patients should be carefully questioned, and the anticoagulation records should be reviewed to determine whether dosages and frequency of antithrombotic medications were adequate ( Fig. 13.1 and Table 13.2 ).

TABLE 13.2

Guidewires and Catheters

Name	Diameter	Length
Guidewires
Bentson/Rosen	0.035 inch	150–180 cm
Angled glide wire	0.035 inch	150–180 cm
Catheters
Pigtail (with 2-cm calibration)	5-Fr	65–90 cm
Kumpe (or another angled catheter)	5-Fr	65–90 cm
Ancillary Supplies
Heparinized saline	1000 U/1000 mL of normal saline
Syringes (2)	20 mL, Luer Lock
Dilators	5-Fr and 6-Fr
Injectable nonionic contrast, high-flow power injector

The routine use of IVC filters in patients with PE who are receiving concurrent anticoagulation is not indicated for most patients. Recent trials have demonstrated that routine filter placement does not decrease the risk for recurrent PE or mortality, but it may increase the risk for lower extremity DVT. Because of the limited number of studies, however, this recommendation against IVC filter placement may not apply to all groups of patients. Those with massive PE (with hypotension) might benefit from an IVC filter.

Imaging