Stent Retention on Catheter Balloon via Controlled Heating and Pressurization
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Solution Overview
Problem
Existing methods for retaining stents on catheters during intravascular procedures face challenges in securely mounting drug delivery stents without damaging them, and in preventing stent dislodgement during delivery and deployment, while also ensuring the balloon's functionality is not inhibited.
Innovation Solution
A method involving the application of radially compressive forces and controlled heating and pressurization of the balloon within a mold to securely embed the stent, using a metallic mold with precise temperature control to prevent damage to the drug delivery layer and enhance stent retention without affecting balloon expansion capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent is strongly fixed to the balloon, then stent retention is improved, but balloon expansion and stent release are inhibited
Solution Approach 1:
The patent applies parameter changes by controlling temperature and pressure during the stent mounting process. The balloon is heated to a specific temperature range (37°C to 60°C) and pressurized to specific ranges (5-300 psi) to achieve optimal retention without excessive bonding. This resolves the contradiction by finding the right parameter window that provides sufficient retention while maintaining expandability and releasability.
Solution Approach 2:
The patent applies preliminary anti-action by pre-treating the balloon surface with plasma or chemical agents before stent mounting. This creates a controlled surface energy state that provides moderate adhesion - strong enough to prevent dislodgement during delivery but weak enough to allow expansion and release at the target site.
2Reliability
If the stent is securely mounted on the balloon, then stent dislodgement is prevented, but the drug delivery layer may be damaged
Solution Approach 1:
The patent carefully controls temperature parameters during mounting to stay within safe ranges for the drug delivery layer (37°C to 60°C). This prevents thermal degradation of the drug while still providing sufficient heat to activate the adhesive or soften the balloon material for secure mounting.
Solution Approach 2:
The patent introduces an intermediary adhesive layer or plasma treatment between the stent and balloon that provides secure bonding without requiring direct high-heat or high-pressure contact with the drug delivery layer. This intermediary protects the sensitive drug coating while achieving reliable retention.
3Reliability
If the balloon is pressurized and heated to secure the stent, then stent retention is enhanced, but the drug delivery layer may be damaged
Solution Approach 1:
The patent defines specific parameter ranges: temperature 37°C to 60°C and pressure 5 to 300 psi. These parameters are optimized to provide sufficient thermal and mechanical energy for secure mounting while remaining below thresholds that would damage the drug delivery layer.
Solution Approach 2:
The patent applies periodic or controlled-duration heating and pressurization rather than continuous extreme conditions. The balloon is pressurized and heated for a limited time period sufficient to achieve retention, then returned to normal conditions, preventing cumulative damage to the drug layer.
4Reliability
If a radially compressive force is applied to decrease stent outer diameter, then stent retention on balloon is improved, but stent structure may be damaged
Solution Approach 1:
The patent applies controlled compressive forces within specific pressure ranges (5-300 psi) that are sufficient to crimp the stent onto the balloon and improve retention, but remain below the yield strength of the stent material to prevent permanent structural damage or deformation of the stent struts.
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 method effectively secures the stent on the balloon catheter without damaging the drug delivery layer, ensuring consistent and reliable stent deployment while maintaining balloon functionality, thereby reducing restenosis and improving procedural outcomes.
Implementation Method 1
the balloon is heated and inflation media is introduced into the interior of the balloon to radially expand the balloon
Implementation Method 2
applying a radially compressive force on an outer surface of the stent, thereby decreasing the outer diameter of the stent on the balloon catheter
Data Source
AI summary
A method of securely mounting a stent on a balloon of a catheter. The method generally includes crimping a stent on a balloon of a catheter at least one time, and positioning the balloon with the stent thereon within a polished bore of a mold formed at least in part of a metallic material. The balloon is pressurized and heated within the mold, or within a sheath, in two stages as the stent is restrained from radially expanding. The method may include crimping the stent onto the balloon one or two times during processing. The method increases retention of the stent on the balloon catheter following sterilization.