Bifunctional Stent with Breakable Cover for Bifurcation Sites
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Solution Overview
Problem
Current stents designed for straight arteries are inadequate for bifurcation sites, leading to challenges such as stent deformations, strut fractures, and increased risk of periprocedural myocardial infarction due to complex vessel geometry and blood flow changes at bifurcation sites.
Innovation Solution
A bifunctional expandable stent with a balloon-expandable body portion and a self-expandable trumpet portion, where a breakable cover maintains the trumpet portion in a compressed state until the balloon expands to a critical diameter, allowing the trumpet to self-expand and secure the bifurcation site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a straight tubular stent is used, then the stent structure is simple and easy to manufacture, but it cannot adequately cover bifurcation sites and causes stent deformations
Solution Approach 1:
The stent is divided into two functional segments: a balloon-expandable body portion and a self-expandable trumpet portion. This segmentation allows each portion to be optimized for its specific function - the body portion provides structural support while the trumpet portion enables adequate coverage of the bifurcation site without causing deformations
Solution Approach 2:
The stent combines two expansion mechanisms (balloon-expandable and self-expandable) in a single device, making it universally applicable to bifurcation sites while maintaining manufacturing feasibility through modular design
2Reliability
If a bifurcation stent with trumpet portion is used, then the stent coverage is adequate, but the device complexity increases
Solution Approach 1:
By segmenting the stent into distinct functional portions with different expansion characteristics, the complexity is managed through clear functional separation rather than a single complex mechanism, achieving adequate coverage while controlling overall device complexity
3Adaptability or versatility
If the trumpet portion is self-expandable, then the stent can adapt to complex anatomies, but it requires a breakable cover mechanism increasing device complexity
Solution Approach 1:
The breakable cover is pre-positioned over the trumpet portion to maintain compression during delivery. The cover is designed to break at a predetermined point during balloon inflation, automatically enabling self-expansion without requiring additional complex control mechanisms
Solution Approach 2:
The breakable cover acts as an intermediary element that temporarily constrains the trumpet portion during delivery and then automatically releases it through a simple breakage mechanism, enabling anatomy adaptation without complex active control
4Reliability
If two dedicated stents are used for branches, then the coverage is complete, but the procedure complexity and risk increase
Solution Approach 1:
The invention merges the functions of two separate stents (body stent and branch stent) into a single integrated bifurcation stent with a trumpet portion that naturally extends into the branch, completing coverage while simplifying the procedure to a single-device deployment
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 bifunctional stent effectively expands to cover bifurcation sites, reducing the risk of stent deformations and strut fractures, while providing optimal coverage and safety by self-expanding to fit complex anatomies.
Implementation Method 1
inflation of the balloon expands the balloon-expandable body portion and expands the self-expandable trumpet portion to a critical diameter
Implementation Method 2
at which the breakable cover breaks to allow the self-expandable trumpet portion to self-expand
Implementation Method 3
the self-expandable trumpet portion is constructed of a second metal or metal alloy and has a fixed end connected to the proximal end of the balloon-expandable body portion and a free end, the self-expandable trumpet portion is compressible thereby forming a compressed trumpet
Implementation Method 4
allow the self-expandable trumpet portion to self-expand
Data Source
AI summary
A bifunctional expandable stent delivery assembly having a bifunctional expandable stent, a breakable cover, and a balloon. The bifunctional expandable stent has a balloon-expandable body portion and a self-expandable trumpet portion. The breakable cover fits over only the self-expandable trumpet portion and prevents self-expansion. The balloon is used to expand the balloon-expandable portion, which breaks the breakable cover and allows the self-expandable trumpet portion to self-expand. A method of stenting a patient using the bifunctional expandable stent delivery assembly is also provided.