Teaching Case

A 39-year-old female patient came to us with a previous history of deep venous thrombosis for which an IVC filter was placed in an outside centre. The patient now wanted the filter to be removed. The patient reported a history of pre-existing comorbidities including diabetes, hypertension, hypothyroidism and morbid obesity.

The patient was evaluated with Doppler scan of the lower limbs which now showed no evidence of deep venous thrombosis.The IVC filter was placed a year before. The patient was instructed about conventional cavogram and IVC filter removal. A right internal jugular vein approach with ultrasound guidance was made. The IVC filter was visualised in its normal deployed position and retrieval was attempted. Partial collapse of the initial portion of the filter was noted. The struts, however, were embedded within the wall of the IVC. Multiple attempts were given, however, the filter did not release from its position. A plan to leave the retrievable filter was made after taking check cavogram runs. The patient was continued on anticoagulants.

IVC filter placement is a therapeutic option available in patients with deep venous thrombosis. It is highly accepted in cases were anticoagulants either are contraindicated or fail to work [1]. Two types of filters are available, 1) Permanent filters which were first available in the 1970s for long term usage [2] and 2) Retrievable which were available in the 1990s, designed to be left in place or retrieved after the temporary risk had subsided [3].The retrievable filters were associated with lower long-term complication rate in comparison to their counterparts which includes: Filter migration, IVC stenosis or further development of deep venous thrombosis [4].The main indications for IVC filter placement includes absolute contraindication to anticoagulant, complications of anticoagulant or failure of anticoagulant. As with every procedure, IVC filter is related to various complications including those that are procedure-related, post procedure-related and filter retrieval-related. Complications related to retrieval include a) filter-related complications and b) IVC injury.
MAUDE database shows 111 cases of retrieval complications [3]. Retrieval rates can vary from 50-100% and are mainly dependant on embedded, tilted or thrombosed filters [3, 5]. Embedded struts, long dwelling time and tilted filters are associated with higher risk of IVC retrieval injury. A success rate of 97% retrieval have been reported irrespective of the dwell time [6]. Prolonged IVC filters are associated with a retrieval rate of <50% in many studies [7, 8]. A clear time period has not been described, however, several studies show that prolonged indwelling filter retrieval is difficult with low retrieval rates [9]. The American College of Chest Physician guidelines suggests that the filter has to be removed in six months irrespective of the coagulation status.

Take home message: IVC filter placement is a very effective treatment option available in patient with deep venous thrombosis, however, filters placed for a prolonged period are very difficult and sometimes impossible to retrieve.

Written informed patient consent for publication has been obtained.