Historical Background

Venous interruption for the prevention of pulmonary embolism 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 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 indications¹ 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 pulmonary embolism, it may be contraindicated for several reasons. Active internal bleeding is an absolute contraindication to therapeutic anticoagulation. However, an increased risk of bleeding due to 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. Currently, however, several alternative anticoagulants are available, and they should be considered prior to insertion of an IVC filter. Direct-thrombin inhibitors are very effective antithrombotic alternatives to heparin or low-molecular-weight heparin in patients who develop heparin-induced thrombocytopenia. Subcutaneously injected low-molecular-weight heparins and pentasaccharides, as well as oral direct-thrombin inhibitors, are potential alternatives in patients with warfarin-induced skin necrosis.

TABLE 13–1 Indications for Placement of an Inferior Vena Cava Filter

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

An often-cited indication for IVC filter insertion is “failure of anticoagulation.” Significant proximal DVT extension and pulmonary embolism 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 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 (Table 13-2; Fig. 13-1; see also Table 13-1).

 TABLE 13–2 Guidewires and Catheters