Stent longitudinal strength assessed using point compression: insights from a second-generation, clinically related...

Area of Science:

• Biomaterials Engineering
• Medical Device Design
• Cardiovascular Research

Background:

• Stent longitudinal distortion, though rare, can cause adverse clinical events.
• Previous tests applied force to the entire stent hoop.
• A new test simulates clinical scenarios by applying force to a malapposed stent hoop.

Purpose of the Study:

• To evaluate and compare the susceptibility of different stent designs to longitudinal distortion.
• To develop a more clinically relevant bench test for stent deformation.
• To provide insights into stent distortion mechanisms in real-world applications.

Main Methods:

• Six stent designs (5 examples each) with 3-mm diameters were tested.
• Stents were malapposed in a 3.5-mm tube, with the proximal 5 mm intentionally displaced.
• An Instron device applied localized force to the proximal stent hoop, measuring force and compression.
• Deformation, malapposition, and lumen obstruction were assessed.

Main Results:

• The Biomatrix Flex stent exhibited the highest resistance to deformation.
• The Element stent demonstrated the greatest susceptibility to distortion.
• Promus Premier design modifications reduced distortion potential compared to the Element.
• Vision, Multi-Link 8, and Integrity designs showed moderate distortion resistance.

Conclusions:

• The second-generation test provides a more accurate assessment of clinical stent distortion.
• Stent design significantly impacts resistance to longitudinal distortion.
• Specific design features, like increased connectors, can improve distortion resistance.