Softness of endovascular coils

Endovascular aneurysm treatment with the Numen coil embolization system: A prospective, randomized, controlled, open-label, multi-center, non-inferiority trial in China

OBJECTIVES

We investigated the safety and efficacy of the Numen coil in comparison to the Axium coil in the treatment of intracranial aneurysms.

METHODS

As CATCH is a prospective, randomized, controlled, open-label, non-inferiority trial conducted in ten centers across China, subjects who fulfilled the inclusion and exclusion criteria were randomized 1:1 to either a test group (Numen) or a control group (Axium). The primary outcome was based upon the successful aneurysm occlusion at the six-month follow-up, while secondary outcomes included technical success, the recanalization and retreatment rates, the rate of serious adverse events (SAE) at the six-month and 12-month follow-up.

RESULTS

Between August 2017-December 2019, a total of 350 subjects presenting with 350 aneurysms were enrolled and randomized. Per-protocol analysis revealed that the successful aneurysm occlusion rate at six months was 91.18% for the test group as compared to 91.85% in the control group, with a difference of -0.68% (p = 0.8419), while the overall mortality rates during the 30-day follow-up period were 1.19% and 1.81% in the test and control group, respectively showing no significant difference between the two groups (p = 0.6837) whereas the SAEs incidence during the 12-month follow-up period was 12.50% and 17.47% in the test and control group, respectively which was not statistically significant (p = 0.2222).

CONCLUSION

This trial demonstrated that the Numen coil was non-inferior to the Axium coil in terms of intracranial aneurysm embolization and can be considered as a safe and effective coils for treating intracranial aneurysm patients in clinical practice.

Is a small coil more effective as a finishing coil for the embolization of intracranial aneurysms? Outcomes using GALAXY G3™ MINI micro-coils as finishing coils in a single center

OBJECTIVE

The purpose of this study was to compare the outcomes of coil embolization using a 0.009 inches primary outer diameter coil as finishing coil (FC) to that of 0.01 inches.

METHODS

From February and August 2020, 131 aneurysms that performed coil embolization using FC with a second loop diameter of 1 mm, were reviewed retrospectively, conducting propensity score matching and logistic regression analysis. Angiographic results such as, occlusion grade, packing density, failure and event were compared between 0.009 inches coil of GALAXY G3™ MINI microcoil (n = 54) and 0.01 inches coils (n = 77).

RESULTS

There were no statistically significant differences between two groups, but more events occurred in the 0.009 group. (Odds ratio, 3.65; 95% CI, 1.06-12.55; P = 0.031) In the results of coil embolization, successful occlusion occlusion (complete occlusion and residual neck) was identified more in the 0.01 group. After propensity score matching, the variables in each group were similar, but the successful occlusion was higher in the 0.01 group as in the total population. Events tended to occur more frequently in the 0.009 inch group, and logistic regression analysis showed slightly higher events in the angled microcatheter. (48.3% versus 76.9%., P = 0.075), Also, the 0.009 inch FC is an independent risk factor. (Odds ratio, 3.84; 95% CI, 1.07-13.80; P = 0.039).

CONCLUSIONS

Using 0.01 inches coils as FC increased the packing density after the procedure, and showed more successful occlusion than using a 0.009 inches coil. The probability of unexpected events was observed more than three times in the 0.009 inch group.

In-vitro pliability assessment of embolization coils for intracranial aneurysm treatment

BACKGROUND

Embolization coils have routinely been used to treat intracranial aneurysms via an endovascular approach. Soft coils are typically viewed as the best design for filling and finishing the aneurysms to achieve a higher packing density and are hypothesized to exert a lower force against the aneurysm wall during deployment. We report here an in vitro pliability test method to assess clinically relevant coil softness and compare these metrics for two commercially available framing and finishing coil products.

METHODS

A force measurement sensor was affixed onto a side-wall synthetic aneurysm model to continuously measure forces on the aneurysm wall during coil deployment at a fixed delivery rate. A quantitative overall energy metric (average work number or AWN) was calculated from the force-displacement graph representing coil delivery into the aneurysm. Two groups of coils were evaluated: (a) finish coil group (N = 20 ea.): Axium™ Prime Extra Soft coil (ES) and Target™ 360 Nano coil (Nano), and (b) frame coil group (N = 20 ea.): Axium™ Prime FC coil (FC) and Target™ 360 Standard coil (Standard).

RESULTS

(a) In the finish coil group, AWN was measured as: ES (0.53 ± 0.09 gf-cm) and Nano (0.99 ± 0.21 gf-cm). (b) In the frame coil group, AWN was measured as FC (2.54 ± 0.53 gf-cm) and Standard (4.48 ± 0.52 gf-cm). In both groups, Axium Prime coils had statistically lower measures of AWN and therefore higher pliability compared to Target coils (p < .001).

CONCLUSIONS

The in-vitro pliability test method offers quantitative metrics to assess coil softness during deployment in a clinically relevant aneurysm model.

Advances in Biomaterials and Technologies for Vascular Embolization

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.

Evaluation of a second-generation self-expanding variable-porosity flow diverter in a rabbit elastase aneurysm model

BACKGROUND AND PURPOSE

The self-expanding V-POD is a second-generation flow-diverting device with a low-porosity PTFE patch on a self-expanding microstent. The authors evaluated this device for the treatment of elastase-induced aneurysms in rabbits.

MATERIALS AND METHODS

Three V-POD types (A, circumferential patch closed-cell stent [n = 9]; B, asymmetric patch closed-cell stent [n = 7]; and C, asymmetric patch open-cell stent [n = 4]) were evaluated by using angiography, conebeam micro-CT, histology, and SEM. Aneurysm flow modifications were expressed in terms of immediate poststent/prestent ratios of maximum CA volume entering the aneurysm dome tracked on procedural angiograms. Flow modifications were correlated with 4 weeks' follow-up angiographic, micro-CT, histologic, and SEM results.

RESULTS

Mechanical stent-deployment difficulties in 4 aneurysms (1 type A; 3 type B) led to suboptimal results and exclusion from analysis. Of the remaining 16 aneurysms, 4-week post-treatment angiograms showed no aneurysm filling in 10 (63%), 3 (∼19%) had no filling with a small remnant neck, and 3 (∼19%) had <0.25 filling. Successfully treated aneurysms (n = 16) demonstrated an immediate poststent/prestent CA maximum volume ratio of 0.13 ± 0.18% (0.0%-0.5%). Favorable contrast-flow modification on immediate angiography after deployment correlated significantly with aneurysm occlusion on follow-up angiography, micro-CT, and histology. The occlusion percentage derived from micro-CT was 96 ± 6.8%. Histology indicated advanced healing (grade ≥3) in the aneurysm dome in 13 of 16 cases. SEM revealed 15 of 16 stents in an advanced state of endothelialization.

CONCLUSIONS

This study showed the feasibility and effectiveness of V-POD for aneurysm healing in a rabbit elastase model.