Thin film nitinol microstent for aneurysm occlusion

Area of Science:

• Biomaterials Engineering
• Medical Device Design
• Cardiovascular Research

Background:

• Small vessel aneurysms pose significant treatment challenges.
• Existing microstent technologies have limitations in deliverability and radial support.
• Nitinol's unique properties offer potential for advanced microstent designs.

Purpose of the Study:

• To develop and evaluate thin film nitinol microstents for treating small vessel aneurysms.
• To assess the mechanical properties and deliverability of these novel microstents.
• To confirm the feasibility of in vivo deployment in cranial vasculature.

Main Methods:

• Fabrication of thin film nitinol microstents using "hot-target" DC sputter deposition.
• Characterization of nitinol film properties, including stress-strain and differential scanning calorimetry.
• Mechanical testing in a flow loop, theoretical calculations of forces, and evaluation of radial force.
• In vivo deployment studies in swine cranial vasculature.

Main Results:

• Nitinol films exhibited an austenite finish temperature (Af) of ~36°C, enabling body-activated response.
• Microstents were successfully compressed and delivered through <3 Fr catheters.
• Theoretical and experimental evaluations confirmed the radial force exerted by the stents.
• Accurate and consistent deployment of microstents was achieved in swine cranial vasculature.

Conclusions:

• Thin film nitinol microstents are a viable technology for treating small vessel aneurysms.
• The fabricated microstents offer excellent deliverability and body-activated functionality.
• In vivo studies confirm the potential for accurate and consistent clinical application.