Inferior Vena Cava Filters

Indications for inferior vena cava (IVC) filter insertion can be categorized as absolute, relative, and prophylactic. In reality, all vena caval filters are “prophylactic.” However, this term has been used to describe the indication for patients at risk who have no identifiable pulmonary embolism (PE) or deep venous thrombosis (DVT).

Absolute indications in patients with venous thromboembolism (VTE) include (1) venous thromboembolic complications associated with a contraindication to anticoagulation, (2) documented failure of anticoagulation, and (3) complications of anticoagulation. Evidence suggests that most patients treated with vena cava filters have none of the 3 accepted absolute indications. ¹

Relative indications in patients with VTE exist when the risk of PE is high despite anticoagulation or when the risk of bleeding complications would be high with anticoagulation. Such indications include large free-floating thrombus in the vena cava, massive PE, DVT in patients with limited cardiopulmonary reserve or where patients are suspected to be noncompliant with anticoagulation.

Prophylactic indications occur in patients who have neither DVT nor PE but in whom the perceived risk of VTE is high and the efficacy of alternative forms of prophylaxis is considered poor or associated with high bleeding risk.

The only randomized trial on IVC filters versus no filtration evaluated the adjunctive benefit of filters in patients with acute DVT undergoing routine anticoagulation. ² The primary end point was PE at 12 days and patients randomized to IVC filters had significantly fewer PE versus those without a filter (1.1% vs 4.8%). Eight-year follow-up data showed that the cumulative recurrent PE rate was 6.2% in patients with filters versus 15.1% in those without. However, patients receiving filters had an increased incidence of recurrent DVT at 2 years (20.8% vs 11.6%) and at 8 years (35.7% vs 27.5%). Unfortunately, multiple filter types were used and not all filters achieve the same results.

It has been observed that thrombotic risk and retrievability (of optional filters) varies between filters. ³ Filters that cause regions of flow stagnation and recirculation at the vena cava wall or turbulence in the vein have an increased risk of thrombosis.^4,5 These hemodynamic observations have translated into clinically relevant findings as observed in a randomized trial. ⁶

A recent Cochrane review of IVC filters to prevent PE confirmed lack of information as to efficacy of filters. ⁷ Therefore, strong recommendations cannot be given for IVC filters on the basis of established evidence.

Increasing numbers of optional (retrievable) filters are being used. A recent systematic review of retrievable IVC filters comprising 37 studies and 6834 patients found a mean retrieval rate of 34%. ⁸ Complication rates included DVT (5.4%), filter migration (1.3%), and vena cava thrombosis/stenosis (2.8%). The IVC filter fractures comprised 22% of the filter complications.

In another recent review, problems after IVC filter insertion were categorized as early or late complications. ⁹ Early complications included incomplete or asymmetric deployment, malpositioning, or tilting, with a reported incidence of 1% to 12.4%. Late complications including filter migration, filter disruption, caval thrombosis, caval perforation, and recurrent PE were reported in 1.7% to 33% of the cases. Some complications were more frequent with some types of filters. Filter migration and tilting were more common with Bard filters compared to other types. The IVC thrombosis was commonly seen with TrapEase (Cordis) filters in patients with underlying malignancy or other hypercoagulable states. The incidence of other complications appeared to be similar among various IVC filters. ⁹

Recommendations

Patients who have PE or proximal DVT with contraindications to anticoagulation should receive an IVC filter (level of evidence: moderate).

Patients who have recurrent acute PE despite therapeutic anticoagulation should receive an IVC filter (level of evidence: low).

Patients with acute PE and poor cardiopulmonary reserve should be considered for an IVC filter (level of evidence: low).

Patients who receive a retrievable IVC filter should be evaluated for filter removal within the specific filter’s retrieval window (level of evidence: low).

An IVC filter should not be used routinely as an adjunct to anticoagulation (level of evidence: low).

Patients receiving an IVC filter due to a contraindication to anticoagulation should be restarted on anticoagulation whenever the contraindication no longer exists (level of evidence: low).