Low Profile Stent Delivery System with Auxiliary Expander
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Solution Overview
Problem
Conventional balloon expanded stent delivery systems face limitations in being manufactured to fit through low profile sheaths, such as seven French or less, due to practical limitations in producing small diameter catheters and balloon structures, restricting the deployment of stents to small diameter passageways.
Innovation Solution
A low profile stent delivery system with a balloon catheter and a crimped balloon expandable stent at separate locations, utilizing an auxiliary expander to transition the stent from a crimped state to a less than fully expanded state, allowing the system to be slid through small sheaths and expanded at the treatment site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the stent is mounted in a crimped state on a folded deflated balloon in a typical structure, then the stent can be delivered through the catheter, but the outer diameter of the stent deployment system becomes too large to fit through low profile sheaths (seven French or less)
Solution Approach 1:
The patent divides the stent deployment system into two separate locations: a first location for the deflated balloon and a second location for the crimped stent. This segmentation allows the balloon and stent to be positioned separately along the catheter, reducing the overall outer diameter profile and enabling passage through low profile sheaths while maintaining the ability to deploy the stent at the target site
Solution Approach 2:
The patent utilizes the longitudinal dimension of the catheter by positioning the stent at a second location separated from the balloon at a first location. This spatial arrangement along the length of the catheter reduces the radial profile (outer diameter) of the deployment system, allowing it to fit through small bore sheaths while preserving the functional relationship between balloon and stent during deployment
2Shape
If small diameter catheters and balloon structures are manufactured to reduce the outer diameter, then the system can fit through low profile sheaths, but practical manufacturing limitations prevent achieving the required small dimensions
Solution Approach 1:
By segmenting the system into a deflated balloon at a first location and a crimped stent at a second location separated along the catheter, the patent reduces the required outer diameter without requiring manufacturing of extremely small diameter components. The separation allows each component to maintain adequate dimensions for manufacturability while the overall profile remains small enough for low profile sheath delivery
3Volume of moving object
If the stent is crimped about the deflated balloon in a stacked configuration, then the structure is compact, but the outer diameter remains too large for seven French or less sheaths
Solution Approach 1:
The patent transitions from a radial stacking configuration (where stent and balloon are concentric, maximizing outer diameter) to a longitudinal separation configuration (where stent and balloon are positioned at different locations along the catheter). This dimensional change maintains compactness along the length of the catheter while dramatically reducing the outer diameter to enable passage through low profile sheaths
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
Enables the delivery of balloon expandable stents to small diameter blood vessels previously unreachable, by reducing the overall profile of the stent delivery system and allowing for successful deployment in peripheral small diameter vessels.
Implementation Method 1
The stent expands from a crimped state to a less than fully expanded state responsive to movement of the auxiliary expander from the first configuration to the second configuration
Implementation Method 2
The stent is expanded from the less than fully expanded state to a fully expanded state at the treatment site by inflating the balloon
Data Source
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AI summary
A low profiled stent delivery system includes a balloon catheter with a balloon mounted at a first location, and a balloon expandable stent crimped about the balloon catheter at a second location. The stent expands from a crimped state to a less than fully expanded state responsive to movement of an auxiliary expander from a first configuration to a second configuration. An inner diameter of the stent in the less than fully expanded state is greater than an outer diameter of the balloon in a deflated state. After repositioning the balloon within the less than fully expanded state, the balloon is inflated to fully expand the stent.