Analysis of tilt of the Günther Tulip filter

Clinical outcomes of retrievable inferior vena cava filters for venous thromboembolic diseases

Aim: To identify literature evidence assessing retrievable inferior vena cava filter (rIVCF) for venous thromboembolic diseases. Methods: A systematic literature search was conducted to identify relevant references from the mainstay English and Chinese bibliographic databases (search period: January 2003 to October 2019). Results: 80 original studies with 11,413 patients were included in this review. The success rates of deploying the six types of rIVCFs ranged from 98.4 to 100.0%. Denali had the highest retrieval success rate (95.4-97.6%). The incidence rates of fracture and perforation associated with retrieving the six rIVCFs were less than 2%. Conclusion: The approved rIVCF had comparable clinical profiles, except that Denali was easier to be retrieved than other rIVCF.

Inferior vena cava filter tilting between placement and retrieval is associated with caval diameter and need for complex retrieval techniques

PURPOSE

Inferior vena cava (IVC) filter tilt may lead to apex embedment and need for advanced retrieval techniques. This study assesses factors associated with filter tilt change over time and need for complex retrieval procedures.

MATERIALS AND METHODS

252 consecutive patients underwent retrievable IVC filter placement and removal at a single academic institution over 58 months. 182 (72.2%) patients met inclusion criteria. IVC filters included 168 (92.3%) Gunther Tulip and 14 (7.7%) Option filters. The primary outcome was medial-to-lateral IVC filter tilt change between placement and retrieval. Secondary outcomes included advanced retrieval technique use and multiple retrieval attempts. Independent variables included demographics, IVC diameter, filter hook position relative to the renal veins, and dwell time. Associations were determined using student's t-tests, ANOVA, and linear and logistic regressions.

RESULTS

Mean IVC diameter at placement was 19.2 ± 3.3 mm. Mean filter tilts at placement and retrieval were 6.1 ± 4.9° and 5.2 ± 5.0°, respectively. Mean tilt change was 5.0 ± 5.0°. Larger IVC diameter was associated with greater filter tilt change (p = 0.0004). While IVC diameter did not independently predict retrieval difficulty, greater tilt change and prolonged dwell time were associated with increased advanced retrieval technique use (p = 0.01 and 0.002, respectively). Results were unchanged in a subgroup analysis of patients treated with Gunther Tulip filters.

CONCLUSION

Larger IVC diameter predicts increased filter tilt change, which in turn is associated with challenging retrievals. Attention to IVC diameter during filter placement may anticipate tilt-related complications.

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

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 (G(1)), Left Straight Group (G(2)), and Left Curved Group (G(3)). In G(3), 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 G(1), GTF apex tended to center compared to G(2) (59% vs. 36%, P < 0.01). In G(3), GTF apex tended to center compared to G(2) (71% vs. 36%, P < 0.01). The differences of A(CF) between G(1) and G(2) (2.66 ± 1.80 vs. 4.13 ± 2.07, P < 0.01) and between G(2) and G(3) (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.

Introducer curving technique for the prevention of tilting of transfemoral Günther 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 ± 4.14 degrees. In Group C, the average ACF was 7.1 ± 4.52 degrees. In Group T, the average ACF was 4.4 ± 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 ± 4.59 vs. 5.1 ± 3.82, t = 2.301, p = 0.023). The proportion of severe tilt (ACF ≥ 10°) in Group T was significantly lower than that in Group C (9.3% vs. 24.1%, χ² = 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%, χ² = 5.030, p = 0.025).

Conclusion

The introducer curving technique appears to minimize the incidence and extent of transfemoral Tulip filter tilting.

Optional vena cava filters: indications, management, and results

BACKGROUND

When anticoagulation is contraindicated or ineffective, optional vena cava filters can be used to prevent pulmonary embolism. These devices can be removed within a defined period of time or can remain in the vena cava permanently.

METHODS

The status of optional vena cava filters was studied by a review of the relevant literature found in a selective Medline search from 2000 to 2008, including a Cochrane review and published guidelines.

RESULTS

Optional vena cava filter can be removed up to 20 weeks or even longer after insertion (depending on the filter model) in a small interventional radiological procedure if therapeutic anticoagulation has been achieved or the patient is no longer at risk for venous thromboembolism. Current studies show comparable results for optional filters and permanent filters, but there have not yet been any prospective studies comparing the two filter types.

CONCLUSIONS

Optional vena cava filters are an important addition to the management of venous thromboembolic disease. As only limited data are available to date, the use of optional filters should be considered on an individual case basis.