Introducer Curving Technique for the Prevention of Tilting of Transfemoral Gnther Tulip Inferior Vena Cava Filter

Objective: To determine whether the introducer curving technique is useful in decreasing the degree of tilting of transfemoral Tulip filters. Materials and Methods: The study sample group consisted of 108 patients with deep vein thrombosis who were enrolled and planned to undergo thrombolysis, and who accepted transfemoral Tulip filter insertion procedure. The patients were randomly divided into Group C and Group T. The introducer curving technique was Adopted in Group T. The post-implantation filter tilting angle (ACF) was measured in an anteroposterior projection. The retrieval hook adhering to the vascular wall was measured via tangential cavogram during retrieval. Results: The overall average ACF was 5.8 ${\pm}$ 4.14 degrees. In Group C, the average ACF was 7.1 ${\pm}$ 4.52 degrees. In Group T, the average ACF was 4.4 ${\pm}$ 3.20 degrees. The groups displayed a statistically significant difference (t = 3.573, p = 0.001) in ACF. Additionally, the difference of ACF between the left and right approaches turned out to be statistically significant (7.1 ${\pm}$ 4.59 vs. 5.1 ${\pm}$ 3.82, t = 2.301, p = 0.023). The proportion of severe tilt (ACF ${\geq}10^{\circ}$) in Group T was significantly lower than that in Group C (9.3% vs. 24.1%, ${\chi}^2$ = 4.267, p = 0.039). Between the groups, the difference in the rate of the retrieval hook adhering to the vascular wall was also statistically significant (2.9% vs. 24.2%, ${\chi}^2$ = 5.030, p = 0.025). Conclusion: The introducer curving technique appears to minimize the incidence and extent of transfemoral Tulip filter tilting.