Polymer Stent Crimping Temperature Control for Balloon Retention
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Solution Overview
Problem
Polymeric stents face challenges in retaining structural integrity and maintaining mechanical properties during crimping and deployment, with existing methods being unreliable for predicting behavior and prone to fractures, and lacking effective retention on balloons for delivery through tortuous anatomy.
Innovation Solution
A controlled crimping process is employed, heating the polymer stent to a temperature between 48°C and 54°C to enhance retention force on the balloon without causing detrimental effects on mechanical properties, using a heated crimper to deform the stent to a reduced diameter while maintaining its shape and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the polymer stent is crimped at room temperature, then the crimping process is simpler, but the retention force on the balloon is insufficient and the stent may dislodge during delivery
Solution Approach 1:
The patent applies parameter changes by heating the polymer stent to a specific temperature range (48°C to 54°C) during crimping. This temperature parameter modification increases the polymer's ductility and allows for better retention force on the balloon without causing detrimental effects on mechanical properties after deployment.
2Reliability
If the polymer stent is heated to increase retention force, then the stent retains better on the balloon, but the mechanical properties and structural integrity may be compromised
Solution Approach 1:
The patent precisely controls the heating temperature parameter within a narrow range (48°C to 54°C) to achieve the desired balance. This controlled parameter change provides sufficient retention force while avoiding temperatures that would compromise the polymer's mechanical properties and structural integrity during deployment.
Solution Approach 2:
The patent incorporates feedback mechanisms by monitoring and controlling the heating process to ensure the polymer stent reaches the optimal temperature range without exceeding it. This feedback control prevents overheating that could damage the stent's mechanical properties while ensuring adequate retention force is achieved.
3Productivity
If conventional crimping methods are used, then the process is faster, but the polymer stent is prone to fractures and cracks
Solution Approach 1:
The patent modifies the temperature parameter during crimping to enhance the polymer's ductility and fracture resistance. By heating to 48°C to 54°C, the material becomes more compliant and less prone to cracking during deformation, while the process is optimized to maintain reasonable productivity.
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 significantly improves the retention force of the polymer stent on the balloon, reducing the risk of fractures and maintaining the stent's structural integrity during deployment, allowing for effective delivery and deployment within the body lumen.
Implementation Method 1
heating the polymer stent to a temperature between 48°C and 54°C
Implementation Method 2
plastic deformation of the polymer scaffolding of the stent
Data Source
AI summary
A medical device-includes a polymer stent crimped to a catheter having an expansion balloon. The stent is crimped to the balloon by a process that includes heating the stent to a temperature below the polymer's glass transition temperature to improve stent retention without adversely affecting the mechanical characteristics of the stent when later deployed to support a body lumen.