Expandable Filter Sheath for Below-Knee Atherectomy
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Solution Overview
Problem
Current medical devices for preventing blockage of small vessels during atherectomy techniques, particularly in lower limb vessels, face challenges such as difficulty in accessing and treating lesions due to the smaller diameter and tortuous anatomy of vessels below the knee, and existing methods may not effectively manage plaque particles dislodged during treatment.
Innovation Solution
A medical device comprising an elongated tubular member with a solid walled region and an expandable filter region, featuring a pattern of slits that allows the filter to move between contracted and expanded configurations, is used to prevent blockages. The device is designed for use in atherectomy procedures, allowing for the expansion of the filter region to capture plaque particles and includes a dilation shaft with a balloon for inflation and a locking hub for positioning, enabling effective filtration and collection of debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an expandable filter device is used to capture plaque particles in small vessels, then the filtration effectiveness is improved, but the device complexity increases
Solution Approach 1:
The filter device is divided into multiple sets of slits (4-15 sets) arranged in a pattern around the circumferential wall, with each set containing multiple slits. This segmentation allows the filter to expand into an effective filtration structure while maintaining a relatively simple base design of an elongated tubular member with slits.
Solution Approach 2:
The filter device transitions from a contracted configuration during delivery to an expanded configuration during use. The slits are arranged in a pattern that allows the expandable filter region to move between configurations, enabling the device to adapt to vessel size while capturing plaque particles effectively.
2Reliability
If the filter region is expanded to capture plaque particles effectively, then the filtration capability is improved, but the difficulty of accessing small vessels increases
Solution Approach 1:
The expandable filter device is designed to be nested within a delivery system (catheter or sheath) in a contracted configuration, allowing it to pass through small vessels and tortuous anatomy below the knee. Once positioned at the treatment site, the filter expands to capture plaque particles effectively.
Solution Approach 2:
The filter device dynamically changes from a low-profile contracted state for delivery through small vessels to an expanded state for effective plaque particle capture. The slit pattern enables this transformation while maintaining access to challenging below-the-knee anatomy.
3Area of stationary object
If multiple sets of slits are used to define the expandable filter region, then the filtration surface area is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The filter is segmented into multiple sets of slits (4-15 sets) arranged in a pattern around the circumferential wall. Each set contains multiple slits that, when expanded, create filtration openings. This segmentation increases the total filtration surface area while allowing for standardized manufacturing of the slit pattern.
Solution Approach 2:
The number of slit sets can be adjusted within a range (4-15 sets) to optimize filtration surface area based on specific application requirements. The slit pattern design allows for parameter variation without fundamentally changing the manufacturing approach, balancing filtration area with manufacturability.
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 device effectively prevents blockage of small vessels by expanding to fit the vessel walls, allowing for the capture and collection of plaque particles, facilitating easier access and treatment of lesions, particularly in challenging below-the-knee anatomy, and providing a method for ablating lesions while collecting particles externally.
Implementation Method 1
a balloon attached to the dilator, the balloon configured to inflate and expand the expandable filter region
Data Source
AI summary
A filtering sheath includes an elongated tubular member defined by a circumferential wall and having a distal end, a proximal end, and a lumen extending therebetween. The distal end has a plurality of slits extending through the circumferential wall, the plurality of slits defining an expandable filter region. The plurality of slits are arranged in a pattern that allows the expandable filter region to move between a first, contracted configuration, and a second, expanded configuration.