In neurovascular device development, material choice directly affects performance, safety, and clinical outcomes. Nitinol, a nickel-titanium alloy renowned for its exceptional mechanical properties, is a preferred material for flow diverters (FDs). Its superelasticity, shape memory, and compatibility with microcatheter delivery systems makes it extremely useful for endovascular use.
This blog explains why nitinol remains a preferred material in FD design and how it complements surface technologies like Smart Reactors’ Camouflage™ coating.
Understanding Nitinol: A Nickel-Titanium Alloy with Unique Capabilities
Nitinol is a remarkable material in medical field, particularly for implantable devices like FDs, due to its two exceptional properties that make it well-suited for such applications.
Shape memory: Nitinol can return to a predetermined shape when exposed to body temperature, allowing devices to be compact during delivery and expand precisely once deployed.
Superelasticity: Nitinol can undergo significant deformation and return to its original form without permanent damage, even at body temperature, enabling flexibility and durability in dynamic environments.
Advantages of Nitinol in Flow Diverters
Flexibility in Complex Vascular Anatomy
Neurovascular structures are highly delicate and intricately curved. Nitinols unique mechanical properties enable devices to navigate these curves and maintain wall conformity without kinking or compromising structural integrity.
Consistent Self-Expansion
Nitinol-based flow diverters consistently expand upon deployment, ensuring secure and uniform apposition to vessel walls—an essential factor for effectively redirecting blood flow and facilitating aneurysm occlusion.
High Elastic Strain Limit
Nitinol can endure significant crimping and bending (6–12% strain) without permanent deformation, enabling delivery through small-diameter catheters to distal sites.
Fatigue Resistance
Nitinol can endure millions of cycles of pulsatile stress, minimizing the risk of fatigue-related failure over time. This durability is crucial for long-term implants subjected to continuous vascular motion.
Biocompatibility
With appropriate surface treatment, nitinol is well-tolerated by vascular tissue and demonstrates a low inflammatory response. Its compatibility supports safe integration into the body, reducing the risk of adverse complications.
Limitations and Radiopacity Considerations
Despite its many advantages, nitinol is not naturally radiopaque. As a result, it may be challenging to visualize under fluoroscopy during endovascular procedures. To address this issue, flow diverters are often engineered with:
- Radiopaque markers made from materials such as platinum
- Composite wires, such as drawn filled tubing (DFT), which feature a radiopaque metal core encased in a nitinol shell
Enhancing Nitinol-Based Devices with Camouflage™ Coating
Smart Reactors’ Camouflage™ coating is designed to improve the biological performance of nitinol-based flow diverters. Engineered to address key challenges in endovascular treatment, this coating enhances both the safety and efficacy of implanted devices through multiple mechanisms.
- Improved Hemocompatibility: Camouflage reduces protein adhesion and platelet activation, minimizing the risk of thrombus formation
- Accelerated Endothelialization: By promoting rapid and uniform endothelial cell growth across the aneurysm neck, the coating helps to restore a functional vessel lining, which is critical for long-term vessel healing and aneurysm exclusion.
Nitinol’s combination of superelasticity, fatigue resistance, and deliverability makes it a material of choice for flow diverters. When paired with surface coatings like Camouflage™, it becomes part of a broader solution aimed at reducing complications and improving patient outcomes.
Discover how Smart Reactors can support your device with clinically driven and performance-optimized solutions, Contact us.
