The Development of a Novel Endovascular Grasper for Challenging Inferior Vena Cava Filter Retrieval

BackgroundWhile inferior vena cava (IVC) filters are commonly retrieved using a snare, lateral tilt and fibrosis around struts can complicate the procedure and require sometimes the use of off-label devices. We describe the development of a novel articulating endovascular grasper designed to remove permanent and retrievable IVC filters in any configuration.MethodsFor in vitro testing, the IVC filters were anchored to the inner wall of a flexible tube in a centered or tilted configuration. A high-contrast backlit camera view simulated the two-dimensional fluoroscopy projection during retrieval. The time from the retrieval device introduction into the camera field to complete filter retrieval was measured in seconds. The control experiment involved temporary IVC filter retrieval with a snare. There were 4 comparative groups: 1- retrievable filter in centered configuration; 2 - retrievable filter in tilted configuration; 3 - permanent filter in centered configuration; 4 - permanent filter in tilted configuration. Every experiment was repeated five times, with median retrieval time compared to the control group. For in vivo testing in a porcine model, 6 tilted infrarenal IVC filters were retrieved with grasper via right jugular approach. Comparison analysis between animal and patient procedures was performed for the following variables: total procedure time, the retrieval time, and fluoroscopy time.ResultsThe in vitro experiments showed comparable retrieval times between the experimental groups 1, 2 and 4 and the control. However, grasper removal of a centered permanent filter (group 3) required significantly less time than in the control (29s vs 79s, p=0.009). In the animal model, all IVC filters were retrieved using the grasper with no adverse events. The total procedure time (21.2min vs 43.5min, P=0.01) and the fluoroscopy time (4.3min vs 10min, P=0.044) were significantly shorter in the animal model compared to the patient group. Moreover, in the patient group, 16.7% of retrievals required advanced endovascular techniques and one IVC filter could not be retrieved (success rate= 91.7%) while all the IVC filters were successfully retrieved in the animal model without the use of additional tools.ConclusionThe novel endovascular grasper is effective in retrieving different types of IVC filters in different configurations and compared favorably with the snare in the in vitro model. In vivo experiments demonstrated more effective retrieval when compared to matched patient retrievals.