Case 1
A 31-year-old female patient with symptomatic postpartum deep venous thrombosis of the right leg up to the distal part of the inferior vena cava prophylactically received a suprarenal IVC filter (Recovery G2; Bard Peripheral Vascular) before surgical thrombectomy. Suprarenal position had to be chosen due to short distance between thrombus in the distal IVC and inflow of renal veins. Surgical access was established via venotomy of the common femoral vein and thrombectomy was performed using an occlusion balloon. In a follow-up CT it was noted that the filter had dislodged and tilted towards the right IVC wall with its legs piercing the contralateral wall and extending into the left renal vein, likely during surgical thrombectomy. Because of re-thrombosis despite continued oral anticoagulation with Warfarin, catheter-directed thrombolysis including stenting of the common iliac veins and the IVC was performed. No filter retrieval was attempted because of large amount of clot within the filter.
After 5 weeks of Warfarin therapy the patient was scheduled for retrieval which was considered mandatory due to the displaced and tilted filter with penetrating legs. After introduction of a 14-F sheath (Cook Medical, Bloomington, Indiana, USA), a SOS catheter (Omni 2, 5F, 80 cm, Angiodynamics, New York, USA) together with a Bentson wire (260 cm, Cook Medical, Bloomington, Indiana, USA) and EN Snare (7F, 18–30 mm, Merit Medical, Utah, USA) were used to create a loop. The single loop-snare technique was attempted several times without success because the loop kept slipping around the filter legs. In order to stabilize the loop a second loop using the same technique was formed around the filter tip. Withtwo loops around the filter tip, the filter was successfully pulled away from the wall and into the 14F sheath.
A follow-up venography was unremarkable. Follow-up ultrasound after 6 months showed patent IVC with regular flow. Genetic tests revealed a heterozygous Factor V Leiden mutation and Warfarin therapy was continued for at least 2 years, after which the patient was lost to follow-up.
Case 2
A 50 year old male received an infrarenal IVC filter (Celect, Cook Medical, Bloomington, Indiana, USA) before orthopedic surgery of the lower extremities due to prior history of Factor V Leiden mutation with several previous episodes of deep vein thromboses. After successful surgery and resumption of Warfarin a filter retrieval was attempted 74 days later. Venography revealed a tilted filter with the tip towards the right IVC wall. Standard technique didn’t seem feasible, therefore a loop-snare technique was attempted using the same equipment and technique as mentioned in Case 1. Despite a successful loop around the filter tip, filter retrieval was unsuccessful. At that time the filter was left in place because of an only moderate tilt and only one leg protruding outside the IVC (Fig. 1a). Warfarin was continued for at least a year and then stopped due to repeated anorectal bleeding episodes.
During a CT for macrohematuria more than 8 years later a severe tilt of the filter was seen with two legs around the aorta and one leg eroding the bone of a vertebral body. In a multidisciplinary board the decision for another retrieval attempt was made. 3146 days after implantation the patient was scheduled for a second attempt. Expecting a difficult retrieval an 18-F sheath (Cook Medical, Bloomington, Indiana, USA) was inserted into the right jugular vein. Venography confirmed a tilted filter with the tip deeply embedded into the IVC wall and two legs protruding outside the IVC (Fig. 1b). Two loops were formed around the filter tip using the same instruments previously described: two reversed shape SOS-catheters (Omni 2, 5F, 80 cm, Angiodynamics, New York, USA) were placed below the filter and two exchange length Bentson wires (260 cm, Cook Medical, Bloomington, Indiana, USA) were navigated on both sides of the filter tip. Above the tip the wires were snared. A second view confirmed one loop on each side of the filter tip (Fig. 1c). During traction both loops started to slip away from the tip, therefore a third loop was created (Fig. 1d) again using a Bentson wire. With 3 loops around the filter tip, the filter could be removed from the wall and finally pulled into the 18F sheath. Configuration of the 3 loops around different filter struts was documented after retrieval (Fig. 1e). During final traction the patient expressed stinging pain in the back. Post-interventional venography showed a large contrast pocket was visible at the location of the embedded filter tip (Fig. 1f) without a true extravasation. An immediate CT did not show extravasation or retroperitoneal hematoma. Because the patient was hemodynamically stable no further treatment was undertaken.
A venography 6 weeks later showed a regular shape of the IVC with only minimal narrowing (Fig. 1g).