Uniform Polymer Scaffold Crimping via Thermal Balloon Pressurization
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Solution Overview
Problem
Polymeric scaffolds face challenges in maintaining structural integrity during crimping and balloon expansion, with issues of non-uniform deployment, reduced fatigue life, and inadequate retention force on delivery balloons, due to their brittle nature and anisotropic properties, which existing methods fail to address effectively.
Innovation Solution
A crimping process that involves inflating the delivery balloon during the crimping of the scaffold, maintaining pressurization throughout the process, and applying balloon pressure during dwell periods to ensure uniform expansion and increased retention force, while heating the scaffold to a temperature near its glass transition temperature to enhance deformation without structural damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the scaffold is crimped to reduce its diameter for delivery, then the scaffold can be delivered through tortuous anatomy, but the scaffold may experience structural failure or excessive cracking
Solution Approach 1:
The patent applies temperature parameter changes by heating the scaffold to near its glass transition temperature during crimping. This thermal parameter change makes the brittle polymer material more compliant and deformable, allowing the scaffold to be crimped to a smaller diameter without causing structural failure or excessive cracking, while maintaining structural integrity
Solution Approach 2:
The patent applies preliminary action by pre-heating the scaffold before crimping. This preliminary thermal treatment prepares the scaffold material to be more tolerant of the mechanical deformation that will follow, preventing structural failure during the subsequent crimping process
2Length of moving object
If the scaffold is crimped to a smaller size, then delivery profile is reduced, but non-uniform deployment occurs leading to reduced fatigue life
Solution Approach 1:
The patent maintains temperature parameter control during crimping by heating the scaffold to near its glass transition temperature. This thermal parameter change ensures uniform deformation of the polymer material during crimping, which translates to uniform deployment characteristics and prevents the non-uniformity that would lead to reduced fatigue life
Solution Approach 2:
The patent applies feedback by monitoring and controlling the crimping process parameters, including temperature and crimping force, to achieve uniform deformation. This feedback control ensures that the scaffold is crimped uniformly, preventing irregularities that would compromise fatigue life during subsequent deployment
3Stability of the object's composition
If the scaffold is made from polymer material, then the scaffold is bio-absorbable, but the scaffold has low strength to weight ratio requiring thicker struts
Solution Approach 1:
The patent applies parameter changes by utilizing temperature near the glass transition temperature of the polymer material. This thermal parameter change temporarily alters the mechanical properties of the polymer, making it more deformable and allowing thinner struts to achieve the required structural performance, thereby reducing scaffold mass while maintaining bio-absorbability
4Device complexity
If the scaffold is crimped without sufficient retention force, then the crimping process is simpler, but the scaffold may become separated from the balloon during transit
Solution Approach 1:
The patent applies parameter changes by utilizing temperature near the glass transition temperature of the polymer during crimping. This thermal parameter change enhances the adhesion between the scaffold and balloon through increased molecular mobility and friction, providing sufficient retention force to prevent scaffold separation during transit through tortuous anatomy without complicating the crimping process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process improves the uniformity of scaffold expansion, increases the retention force between the scaffold and balloon, and ensures safe delivery by maintaining structural integrity, reducing the risk of fracture and fatigue failure, and enhancing the scaffold's ability to maintain its shape during deployment.
Implementation Method 1
heating the scaffold to a temperature near its glass transition temperature to enhance deformation without structural damage
Implementation Method 2
A crimping process that involves inflating the delivery balloon during the crimping of the scaffold, maintaining pressurization throughout the process, and applying balloon pressure during dwell periods
Data Source
AI summary
A medical device-includes a scaffold crimped to a catheter having an expansion balloon. The scaffold is crimped to the balloon by a process that includes one or more balloon pressurization steps. The balloon pressurization steps are selected to enhance scaffold retention to the balloon and maintain a relatively uniform arrangement of balloon folds about the inner surface of the crimped scaffold so that the scaffold expands in a uniform manner when the balloon is inflated.