Extraction of fractured inferior vena cava filter strut from pulmonary artery using Inari FlowTriever system

Abstract

Inferior vena cava (IVC) filter retrieval is generally considered safe in the setting of deep vein thrombosis, but complications can arise during extraction. In this report, we describe the case of a 64-year-old male who underwent IVC filter placement prior to spine surgery for intractable pain and inability to ambulate. Filter extraction was attempted approximately 1 month later, when one of the filter struts fractured and embolized into the pulmonary artery. This case demonstrates a novel physician-modified retrieval technique using a telescoping T24-T16 catheter system and a customized snare, successfully employed to extract an embolized IVC filter strut from the pulmonary artery.

Inferior vena cava (IVC) filters are a treatment option in preventing pulmonary emboli caused by deep vein thrombosis (DVT) when anticoagulation is contraindicated as outlined in current American College of Chest Physicians (CHEST) guidelines.¹ Important considerations when placing an IVC filter are the timing of and approach to filter removal. The recommended duration in which filters should be in place is as short as possible, ideally within a 6- to 8-week period to minimize the risk of complications including thrombosis, fracture, or embolization.²

When IVC filters fracture and embolize, retrieval technique depends on fragment location. For fragments within the IVC, endobronchial forceps are preferred for their rigidity,³ with snares reserved as a secondary option.⁴ For fragments in the heart or pulmonary arteries, snares are preferred for their flexibility in navigating cardiac chambers.³ Minor complications such as mild hemoptysis have been reported with pulmonary artery retrieval.⁵ Here, we present a case of IVC filter strut fracture and embolization to the pulmonary artery during an attempted retrieval within the optimal time window, successfully managed using a novel physician-modified retrieval technique employing the Inari FlowTriever system (Supplementary Video, online only).

Case report

A 64-year-old male with a history of degenerative disc disease and prior lumbar spine surgery presented with intractable lower extremity pain and inability to ambulate, requiring L3 to L4 laminectomy and discectomy. Preoperative venous duplex ultrasound revealed an extensive right lower extremity proximal DVT extending from the common femoral to the iliac vein. He underwent pharmacomechanical thrombectomy of the right iliac and femoral veins, and a retrievable IVC filter was placed via right internal jugular vein access, given his inability to receive perioperative anticoagulation. He subsequently underwent successful spinal decompression within 1 week of filter placement and was referred for retrieval once cleared by the surgical team.

Approximately 1 month later, the patient returned for elective filter removal. Right internal jugular vein access was re-established. Using a Cook Gunther-Tulip Retrieval Set (Cook Medical), a 10F sheath was positioned above the filter hook. Multiple hook-capture attempts using a CloverSnare (Cook Medical), a standard loop snare, and retrieval forceps with interventional radiology assistance were unsuccessful, as the filter hook could not be reliably engaged.

Inferior venacavogram demonstrated no thrombus, a centrally positioned filter apex, and no deformity or tilt (Fig 1). Despite these reassuring findings, resistance was encountered during retrieval, suggesting early endothelialization of a strut not apparent on venography.

Fig 1.

Inferior venacavogram obtained at the time of initial filter retrieval, demonstrating a centrally positioned filter apex with no deformity, tilt, or intraluminal thrombus.

After multiple failed hook-capture attempts, an Omni catheter was advanced through the IVC below the filter. A guidewire passed through the Omni catheter was snared from above and brought through the 16F sheath, creating a through-and-through wire configuration. The filter was then drawn into the sheath (Fig 2, A), at which point one strut fractured and embolized into the circulation (Fig 2, B). The fractured strut migrated to the right atrial appendage; retrieval via jugular and femoral access using snares and forceps was unsuccessful.

Fig 2.

(A) Initial inferior vena cava (IVC) filter extraction attempt: the filter apex partially engaged by the 16F sheath via through-and-through wire technique. (B) Strut fracture event: one filter strut separates as the filter body is withdrawn under axial traction.

Computed tomography coronary angiography demonstrated the fractured strut lodged in right pulmonary artery segmental branches without flow limitation (Fig 3). The patient remained hemodynamically stable and asymptomatic throughout.

Fig 3.

Computed tomography coronary angiogram confirming the fractured inferior vena cava (IVC) filter strut lodged within right pulmonary artery segmental branches without flow limitation.

Following multidisciplinary discussion involving vascular surgery, interventional radiology, interventional cardiology, and cardiac surgery, the decision was made to proceed with percutaneous retrieval of the embolized strut.

The patient returned for repeat retrieval with cardiac surgery on standby. Left common femoral vein access was obtained, and an Inari Triever24 (Inari Medical) sheath was advanced through the heart to the right main pulmonary artery. Angiography confirmed the retained strut in the right lower lobar pulmonary artery.

An Inari Triever16 (Inari Medical) catheter was coaxially advanced through the T24 to create a protected working channel. Because a snare catheter longer than the FlowTriever system was required, a physician-modified snare was constructed: a 125-cm 6F Launcher catheter was trimmed at its distal end and loaded with a Merit EnSnare (6-10 mm; Merit Medical), providing ∼10 cm of loop protrusion beyond the Inari catheter tip (Fig 4). This device engaged the strut fragment, which was oversheathed into the T24 and removed (Fig 5).

Fig 4.

Physician-modified snare assembly: a 125-cm 6F Launcher catheter (Medtronic) trimmed at its distal end and loaded with a Merit EnSnare (6-10 mm; Merit Medical), providing ∼10 cm of snare loop protrusion beyond the Inari Triever16 catheter tip.

Fig 5.

(A) The physician-modified snare successfully engages the embolized filter strut fragment within the distal right pulmonary artery. (B) Complete telescoping of the Inari Triever24 over the Triever16 catheter enables oversheathing and full retrieval of the strut fragment without vessel wall contact.

Completion angiography confirmed complete retrieval with patent pulmonary vasculature. Final venography confirmed preserved IVC flow. The patient was discharged on therapeutic oral anticoagulation for DVT management and aspirin. Written informed consent was obtained from the patient for publication of this case report.

Discussion

Standard IVC filter removal involves snaring the retrieval hook and withdrawing it into a vascular sheath, with reported success rates of 74% to 87%.^6,7 When standard technique fails, advanced retrieval methods are employed.

In our patient, standard snares and retrieval forceps could not engage the filter hook despite multiple attempts. A through-and-through wire technique was therefore employed: a catheter was advanced below the filter, and a guidewire passed through it was snared from above, creating a wire loop that engaged the filter body rather than the apex. The 16F sheath was advanced over the filter tip, but with the guidewire loop exiting below the filter body, true push-over-sheath collapse was not achievable from above. The filter body was withdrawn under axial traction, concentrating mechanical stress on individual struts rather than distributing force evenly through an apex-first cone collapse. A focally adherent strut fractured under this traction. The key technical lesson is that the preferred push-over-sheath technique requires secure hook engagement at the filter apex; when hook capture is not achievable, through-and-through wire retrieval is a valuable salvage maneuver but carries a higher risk of strut fracture if strut adherence is present.

When standard retrieval failed, we employed the Inari FlowTriever system (Inari Medical) off-label for metallic foreign body retrieval—a United States Food and Drug Administration–cleared system for pulmonary embolism thrombus aspiration whose large-bore coaxial architecture proved advantageous here. The T24 provided transthoracic large-bore access, while the T16 created a protected working channel to the distal pulmonary vasculature. A snare catheter longer than the FlowTriever system was required; a 125-cm 6F Launcher catheter (Medtronic) was therefore distally trimmed and loaded with a Merit EnSnare (6-10 mm; Merit Medical), providing ∼10 cm of loop protrusion beyond the Inari catheter tip—sufficient to reach the strut while fitting within the T16 lumen.

The modified snare successfully captured the fragment, which was oversheathed into the T24 for retrieval, avoiding the need to withdraw the metallic strut against vessel walls (Fig 5). The FlowTriever system’s large-bore coaxial architecture proved uniquely suited to this application, allowing simultaneous large-bore access and fine-instrument maneuverability within the distal pulmonary artery. This technique may serve as a useful reference for future cases of intrapulmonary or intracardiac IVC filter fragment embolization where standard retrieval devices cannot be deployed distally.

Conclusions

This case illustrates that IVC filter strut fracture and pulmonary embolization can occur during retrieval within the optimal time window, particularly when hook capture fails and a through-and-through wire technique is required. When standard retrieval is unsuccessful, operators should anticipate elevated fracture risk and involve multidisciplinary teams. The off-label use of the Inari FlowTriever coaxial system offers a novel platform for retrieving intrapulmonary metallic foreign bodies in cases where standard devices cannot be deployed distally. Collaborative planning among vascular surgery, interventional radiology, interventional cardiology, and cardiac surgery is essential when managing this rare but serious complication.

Funding

None.

Declaration of generative AI and AI-assisted technologies in the writing process

During the preparation of this work the authors used ChatGPT in order to improve readability and edit sentence structure. After using this tool/service, the authors reviewed and edited the content as needed and take full responsibility for the content of the publication.

Disclosures

None.

From the American Venous Forum