Introducer curving technique to reduce tilting of transfemoral Günther Tulip IVC filter: in vitro study

Abstract

Background

Severe tilting of Günther Tulip filter (GTF) may be associated with difficulty in retrieval.

Purpose

To determine if an introducer curving technique of GTF can decrease the tilting degree of GTF in a caval model.

Material and Methods

The model was constructed by placing Dacron grafts in bifurcated glass tubes. The study included three groups: Right Straight Group (G₁), Left Straight Group (G₂), and Left Curved Group (G₃). In G₃, a 10–20° angle was curved on the metal introducer before insertion to decrease the angle between inferior vena cava axes and metal introducer (A_CM). Before GTF was released, the distance between the caval right wall and the apical hook (D_CH1), and A_CM were measured. The tilt angle of GTF (A_CF) was also measured.

Results

In G₁, GTF apex tended to center compared to G₂ (59% vs. 36%, P < 0.01). In G₃, GTF apex tended to center compared to G₂ (71% vs. 36%, P < 0.01). The differences of A_CF between G₁ and G₂ (2.66 ± 1.80 vs. 4.13 ± 2.07, P < 0.01) and between G₂ and G₃ (4.13 ± 2.07 vs. 2.39 ± 1.79, P < 0.01) were statistically significant. There were significant positive correlations between A_CM and A_CF, whereas significant negative correlations were detected between D_CH1 and A_CF in each group.

Conclusion

The oblique course of GTF delivery system relative to the axis of the cava causes filter tilt, and thus, curving the introducer prior to its introduction helps to reduce the filter tilt. We recommend a clinical study to determine whether the introducer curving technique improves filter centering and its retrievability.