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

Fig 13–1

Imaging

Access and Operative Steps

Inferior vena cavography usually is performed via an internal jugular or common femoral approach (right is preferable to left in both instances). The site for access is often left up to the physician. However, certain clinical situations dictate an optimal strategy. A right internal jugular approach is commonly used, and it usually will not disturb thrombi in the iliac or femoral veins. It also may be used to cannulate either of the common iliac veins in the event that further imaging is needed to visualize potential IVC anomalies. All currently available IVC filters also may be inserted via a jugular approach. A common femoral venous approach may be more advantageous in patients who are intubated or have central venous catheters in place. However, the physician should confirm with duplex imaging that the access site is not involved with the venous thrombosis.

Right Internal Jugular Approach

The internal jugular vein should be cannulated using a combination of anatomic landmarks and ultrasound guidance. The internal jugular vein is located deep to the confluence of the two heads of the sternocleidomastoid muscle. More specifically, it is located deep to the clavicular head of the SCM, about one third of the distance from the medial border to the lateral border of the muscle. A subcutaneous wheel of local anesthetic is injected, and a No. 11 blade is used to incise the dermis. The subcutaneous tissue is spread gently with a mosquito clamp.

An 18-gauge single-wall puncture needle connected to a 5-mL or 10-mL syringe is used to access the vein with ultrasound guidance. The syringe should freely aspirate dark blood, and a .035-inch guidewire is passed into the IVC under fluoroscopic guidance. Occasionally, an angled catheter may be required to steer the wire into the IVC. Alternatively, a 21-gauge needle, .018-in guidewire, and 5-Fr catheter/dilator set (Micropuncture Introducer Set; Cook Medical, Bloomington, IN) may be used to avoid using the larger needle (Table 13-3; Figs. 13-2 through 13-10).

 TABLE 13–3 Right Internal Jugular Approach

• Patient supine, slight Trendelenburg positioning if possible • Slight neck rotation away from the site of access (overrotation beyond 30 to 60 degrees may increase the risk of carotid cannulation) • Internal jugular access about 2 cm superior to the sternoclavicular junction, between the two heads of the sternocleidomastoid muscle, needle directed laterally. • A standard 5- to 10-MHz ultrasound probe is placed transverse to the jugular vein. The syringe is gently aspirated as the needle is used to indent and puncture the anterior wall of the vein. • The guidewire should pass without resistance and fluoroscopy should be used to confirm wire placement into the superior vena cava.

Fig 13–2

Fig 13–3

Fig 13–4

Fig 13–5

Fig 13–6

Fig 13–7

Fig 13–8

Fig 13–9

Fig 13–10

Common Femoral Vein Approach

The common femoral vein usually is accessed using anatomic landmarks alone. The femoral pulse is palpated laterally. Ultrasound guidance may be easily applied in circumstances when the patient is obese or if the femoral pulse is absent. The common femoral vein cannulation techniques with an 18- or 21-gauge needle are similar to those that were described for internal jugular venous access (Figs. 13-11 through 13-16).

Fig 13–11

Fig 13–12

Fig 13–13

Fig 13–14

Fig 13–15

Fig 13–16

Anticoagulation Management

The management of anticoagulation around the time of IVC filter insertion will depend on the indication for the filter. If the filter is to be inserted because of a contraindication to anticoagulation (e.g., active internal bleeding, recent major surgery, trauma, anticoagulation-related bleeding), then the IVC filter can be placed without periprocedural anticoagulation. However, if the indication was venous thromboembolism recurrence despite adequate anticoagulation, then the anticoagulation should not be discontinued around the time of the procedure.³

Pearls and Pitfalls

Once the filter is placed, remember to continually reassess anticoagulation.

If the plan is to remove an IVC filter, hospital programs should be instituted to track patients, ensure follow-up, and arrange for filter retrieval in a timely fashion. In patients who receive a permanent filter, yearly follow-up with plain kidney-ureter-bladder films should be obtained to assess for filter fracture or filter migration.

Complications of IVC Filter Insertion

Complications include pneumothorax, access site thrombosis, pulmonary embolism, filter migration, filter infection, caval thrombosis, and IVC trauma.

Comparative Effectiveness

Success achieved with vena cava filters expanded the indications in some series to prophylaxis for free-floating thrombi longer than 5 cm,⁴ in cases where the risk of anticoagulation was thought to be prohibitive such as in older patients with DVT, after major trauma,⁵ and in high-risk situations such as orthopedic and bariatric operations.⁶ Statistical data to support these indications are lacking, and enthusiasm for permanent vena caval filtration has declined with case reports of caval occlusion and filter fractures.

The development of retrievable filters has rekindled interest in their use, particularly during mechanical or thrombolytic treatment of large iliofemoral thrombi.⁷ Unfortunately, data to date show equivalent complications, less secure fixation, and the added expense of multiple procedures. Improvements in techniques and devices should overcome some of these limitations but not the fundamental problem of knowing when embolic protection is no longer necessary.