Retrieval Catheter Distensible Tip Debris Control
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Solution Overview
Problem
Existing retrieval catheters face challenges in minimizing the likelihood of displacing debris during the withdrawal of protection devices from stented lumens, as they often have discontinuities that can snag or scrape against stent surfaces, leading to the release of debris.
Innovation Solution
A retrieval catheter with a distensible tapered distal tip and a distender that expands the orifice, allowing for safe proximal withdrawal of devices like embolic filters or balloons by capturing their proximal parts within the distender's annulus, reducing the risk of snagging on stent surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the retrieval catheter has a tapered distal tip to be atraumatic during distal advancement, then the catheter can safely advance through the vasculature, but the tapered tip creates discontinuities that can snag or scrape stent surfaces during proximal withdrawal, releasing debris
Solution Approach 1:
The catheter tip transitions from a static tapered shape to a dynamic structure that can expand and contract. The distal tip includes a expandable basket or filter structure that can be collapsed for distal advancement and expanded for stable retrieval, eliminating the harmful discontinuities of a fixed tapered tip while maintaining atraumatic properties.
Solution Approach 2:
The catheter incorporates flexible membrane structures at the distal tip that can conform to the vasculature during advancement and then expand to create a smooth, continuous surface for retrieval. This flexible shell approach eliminates sharp edges and discontinuities that would otherwise snag on stent surfaces.
2Object-generated harmful factors
If the retrieval catheter has a smooth continuous surface to prevent snagging during withdrawal, then debris displacement is minimized, but the catheter loses the atraumatic tapered tip design needed for safe distal advancement
Solution Approach 1:
The catheter employs a dynamically reconfigurable tip structure that changes shape between advancement and retrieval phases. During distal advancement, the tip collapses to a fine profile for safe navigation; during retrieval, it expands to provide a smooth, continuous surface that prevents debris displacement.
Solution Approach 2:
The catheter uses a nested structure where an inner expandable basket or filter is contained within the catheter shaft during advancement. Upon deployment, the inner structure expands outward to create a smooth outer surface, effectively nesting two functional configurations within a single device.
3Stability of the object's composition
If the retrieval catheter uses a rigid structure to maintain shape stability, then the catheter can reliably navigate the vasculature, but the rigid structure creates discontinuities that increase the risk of snagging on stent surfaces during withdrawal
Solution Approach 1:
The catheter replaces rigid structural elements with flexible shell structures that can maintain overall shape stability while conforming to the vasculature. The flexible shell at the distal tip creates a continuous surface that eliminates snagging points, yet the catheter maintains sufficient structural integrity for reliable navigation.
Solution Approach 2:
The catheter employs composite material construction combining rigid support structures with flexible outer surfaces. The rigid framework provides shape stability and pushability, while the flexible outer shell creates a smooth, continuous surface that prevents debris displacement during retrieval.
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 solution effectively minimizes the risk of debris displacement during withdrawal, ensuring atraumatic removal of protection devices through stented lumens by reconfiguring the distal tip to prevent engagement with stent surfaces, thereby maintaining the integrity of the stent and surrounding tissue.
Implementation Method 1
the distender presses radially outwardly the catheter wall within the distal tip, so as to distend said orifice
Data Source
AI summary
A retrieval catheter having a wall that defines a catheter lumen and a distal tip that is tapered towards an open distal orifice that defines the distal end of the lumen, the wall over the length of said tapered tip being distensible to allow the orifice to expand, and a distender within the lumen that can be urged distally along the lumen such that the distender presses radially outwardly the catheter wall within the distal tip, so as to distend said orifice.