Stent Crimping Thermal Control for Drug Coating Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for crimping stents onto balloon catheters often damage the drug-eluting coating due to elevated temperatures, which can affect the stent's performance and integrity.
Innovation Solution
A crimping apparatus with actuatable crimping elements and a system for heating the balloon while maintaining the crimping elements at a lower temperature, using methods such as heated fluids, electromagnetic waves, or heat pumps to control temperature gradients during the crimping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the balloon material is heated to an elevated temperature to soften it for easier conforming to stent contours, then the ease of manufacture is improved, but the drug-eluting coating on the stent is adversely affected
Solution Approach 1:
The system segments the thermal treatment by introducing a temperature gradient along the balloon length. The distal portion is heated to a first temperature (above glass transition) to facilitate crimping, while the proximal portion remains at a second temperature (below coating damage threshold). This spatial segmentation allows simultaneous achievement of easy crimping at the crimping zone while protecting the coating in the non-crimping zone.
Solution Approach 2:
The patent applies local quality by creating different thermal conditions in different spatial locations of the same object (balloon). The balloon material at the distal portion has different thermal properties (softer, more compliant) compared to the proximal portion (maintains structural integrity). This local differentiation enables the crimping operation to proceed easily at the target zone without compromising the stent coating elsewhere.
2Ease of operation
If the balloon is heated uniformly to soften the material for crimping, then the ease of operation is improved, but the stent coating integrity deteriorates
Solution Approach 1:
The heating system is segmented to provide different temperatures at different locations along the balloon. The distal portion receives heating to soften the material for easy crimping operations, while the proximal portion remains unheated or heated to a lower temperature to maintain coating integrity. This spatial segmentation resolves the contradiction between ease of operation and reliability.
Solution Approach 2:
The balloon is preliminarily heated only in the distal portion that will undergo crimping, before the actual crimping operation. This preliminary localized heating softens the material in advance where needed, while preserving the coating integrity in other regions. The heating is applied selectively and temporarily only where and when required.
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
This approach allows for effective crimping of stents onto balloon catheters without compromising the drug-eluting coating, ensuring the stent's performance and integrity by maintaining the coating at a lower temperature while heating the balloon to facilitate crimping.
Implementation Method 1
the balloon material may be heated to an elevated temperature, such as greater than the glass transition temperature of the balloon material, causing the balloon material to soften
Implementation Method 2
the crimping elements are maintained at a temperature less than 40° C.
Data Source
AI summary
Methods of heating and cooling during a crimping process are disclosed. One method includes providing a cooling source to cool the stent and/or drug eluting coating of the stent while crimping the stent onto the balloon, and providing a heating source to heat the balloon while crimping the stent onto the balloon. Another method includes introducing a cooling fluid through a passage in one or more of the plurality of crimping elements of the crimping apparatus to cool the crimping elements while crimping the stent onto the balloon, and introducing a heating fluid through the elongate shaft of the balloon catheter to heat the balloon while crimping the stent onto the balloon.