Bench-Top Comparison of Three Different Types of Stents Used for Treatment of Intracranial Atherosclerotic Stenosis

Abstract

Purpose: Four key bench-top tests, including trackability, conformability, wall-apposition, and bending stiffness, were performed to understand the mechanical characteristics in 3 different types of stents applicable for treatment of intracranial atherosclerotic stenosis: Balloon-expandable D+Storm, Pro-Kinetic Energy, and self-expandable Wingspan stents.

Materials and methods: Trackability was assessed by measuring the tracking forces of each stent with its delivery systems. Conformability and wall apposition were quantified and analyzed using curved vessel models. A 3-point bending test was employed to evaluate bending stiffness.

Results: D+Storm showed the lowest tracking forces while the conformability of the Wingspan stent was superior to that of the tested stents. Pro-Kinetic Energy and D+Storm had better wall apposition in curved vessels than the Wingspan stent. Bending stiffness of the Wingspan stent was notably lower, whereas no significant differences were found between D+Storm and Energy. Pro-Kinetic Energy and D+Storm not only indicated lower gap ratios between the struts and the vessel wall but also maintained good wall apposition even in the curved model.

Conclusion: These bench-top measurements may provide clinicians with useful information in regard to selecting suitable stents for treatment of intracranial atherosclerotic stenosis.

Keywords: Atherosclerosis; Intracranial arterial disease; Stent.

Fig. 1.

Vessel model and stent system for trackability tests: (A) D⁺Storm and Pro-Kinetic Energy stent system, and (B) Wingspan stent system.

Fig. 2.

Schematic images of angle variations of the tested stents (A) before and (B) after stent deployment in the curved segment.

Fig. 3.

Images of test setup of the 3-point bending test for measuring bending stiffness.

Fig. 4.

Tracking force-distance curves of trackability measurements: (A) D⁺Storm, (B) Pro-Kinetic Energy, and (C) Wingspan.

Fig. 5.

Images of angle variation results for measurements of conformability (in the following order): D⁺Storm, Pro-Kinetic Energy, and Wingspan.

Fig. 6.

Images of stent-vessel wall apposition measurements (D⁺Storm, Pro-Kinetic Energy, and Wingspan stents, respectively).

Fig. 7.

Images of apposed stents to the curved vessel wall: D⁺Storm, Pro-Kinetic Energy, and Wingspan.

Fig. 8.

Graphs displaying bending force-displacement curves for measurement of bending stiffness: (A) D⁺Storm, (B) Pro-Kinetic Energy, and (C) Wingspan.