Abstract No. 669 - Mechanisms of Günther Tulip filter tilting: an experimental and clinical investigation

Abstract

PurposeTo characterize mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement using an experimental model.MaterialsIn an experimental study, 120 GTFs were deployed in an inferior vena cava (IVC) model using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall prior to deployment were evaluated. The associations between significant pre-deployment factors noted in the experimental study were then evaluated in a retrospective clinical series of 17 patients.ResultsIn the experimental study, there was a significant association between a high pre-deployment angle (>5°) and post-deployment tilting (P < 0.0001). With a low pre-deployment angle (≤ 5°), there was a significant association between the proximity of the constrained pre-deployment filter legs to the far IVC wall and subsequent filter tilting (P = 0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment tilting was also noted (P = 0.044), with a trend toward statistical significance using an adjusted linear regression model (P = 0.059).ConclusionsThe pre-deployment angle between filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall were associated with GTF tilting in an experimental model. Filter tilt due to proximity of the constrained legs to the IVC wall represents a new factor associated with filter tilting, and a mechanism to explain this is demonstrated. A practical solution is presented to address the identified factors related to filter tilting. PurposeTo characterize mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement using an experimental model. To characterize mechanisms of Günther Tulip filter (GTF) tilting during transfemoral placement using an experimental model. MaterialsIn an experimental study, 120 GTFs were deployed in an inferior vena cava (IVC) model using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall prior to deployment were evaluated. The associations between significant pre-deployment factors noted in the experimental study were then evaluated in a retrospective clinical series of 17 patients. In an experimental study, 120 GTFs were deployed in an inferior vena cava (IVC) model using 6 configurations of pre-deployment filter position. The angle between the pre-deployment filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall prior to deployment were evaluated. The associations between significant pre-deployment factors noted in the experimental study were then evaluated in a retrospective clinical series of 17 patients. ResultsIn the experimental study, there was a significant association between a high pre-deployment angle (>5°) and post-deployment tilting (P < 0.0001). With a low pre-deployment angle (≤ 5°), there was a significant association between the proximity of the constrained pre-deployment filter legs to the far IVC wall and subsequent filter tilting (P = 0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment tilting was also noted (P = 0.044), with a trend toward statistical significance using an adjusted linear regression model (P = 0.059). In the experimental study, there was a significant association between a high pre-deployment angle (>5°) and post-deployment tilting (P < 0.0001). With a low pre-deployment angle (≤ 5°), there was a significant association between the proximity of the constrained pre-deployment filter legs to the far IVC wall and subsequent filter tilting (P = 0.001). In a retrospective clinical study, a significant association between the pre-deployment angle and post-deployment tilting was also noted (P = 0.044), with a trend toward statistical significance using an adjusted linear regression model (P = 0.059). ConclusionsThe pre-deployment angle between filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall were associated with GTF tilting in an experimental model. Filter tilt due to proximity of the constrained legs to the IVC wall represents a new factor associated with filter tilting, and a mechanism to explain this is demonstrated. A practical solution is presented to address the identified factors related to filter tilting. The pre-deployment angle between filter axis and IVC axis, and the proximity of the constrained filter legs to the IVC wall were associated with GTF tilting in an experimental model. Filter tilt due to proximity of the constrained legs to the IVC wall represents a new factor associated with filter tilting, and a mechanism to explain this is demonstrated. A practical solution is presented to address the identified factors related to filter tilting.