Tissue-removing Catheter with Raised Elements for Hard Tissue
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Solution Overview
Problem
Current tissue-removing catheters face challenges in effectively cutting and removing hard tissue and plaque from body lumens, such as blood vessels, due to the limitations of traditional cutting edges and the need for enhanced mechanisms to break up calcified material.
Innovation Solution
The design of a tissue-removing catheter with a cutting element featuring an annular cutting edge and raised elements that extend radially inward, allowing for a combination of cutting and breaking up hard tissue, with the raised elements occupying a small portion of the surface area to maintain cutting efficiency and direct tissue into a chamber for removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional cutting edge is used to remove tissue, then the catheter can cut soft tissue, but it cannot effectively break up hard tissue and plaque
Solution Approach 1:
The cutting element incorporates raised elements with specific geometric features (leading radial walls at predetermined angles) at localized positions on its surface. These raised elements create zones of blunt force application distributed across the cutting element, enabling effective engagement with hard tissue and plaque while maintaining cutting capability for softer tissue.
2Reliability
If raised elements are added to the cutting element to break up hard tissue, then hard tissue removal is improved, but the surface area available for cutting is reduced
Solution Approach 1:
The raised elements occupy only a portion of the cutting element's surface area, specifically designed to cover approximately 10% to 40% of the total surface. This partial coverage provides sufficient blunt force application points for hard tissue disruption while preserving adequate cutting edge surface area for effective soft tissue removal.
3Reliability
If the leading radial wall extends too close to the longitudinal axis, then hard tissue breaking is enhanced, but tissue may become trapped and interfere with the cutting process
Solution Approach 1:
The leading radial wall of the raised elements is positioned to terminate at a radial distance from the longitudinal axis that is between 66% and 95% of the cutting element's outer radius. This specific parameter range optimizes the balance between engaging hard tissue effectively and maintaining sufficient clearance to prevent tissue trapping that would interfere with the cutting operation.
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 catheter effectively cuts and removes hard tissue and plaque by applying a blunt force with the raised elements, ensuring efficient tissue removal without interfering with the cutting process, and directing the tissue into a chamber for collection.
Implementation Method 1
A cutting element at the distal portion of the elongate catheter body has opposite proximal and distal ends and a longitudinal axis extending therebetween. The cutting element is operatively connected to the drive shaft for rotation about a longitudinal axis of the cutting element.
Implementation Method 2
The catheter effectively cuts and removes hard tissue and plaque by applying a blunt force with the raised elements
Implementation Method 3
The catheter effectively cuts and removes hard tissue and plaque by applying a blunt force with the raised elements, ensuring efficient tissue removal
Data Source
AI summary
A tissue-removing catheter includes a cutting element. A radially innermost portion of the leading radial wall of a raised element of the cutting element may be spaced a radial distance from the longitudinal axis that is less than 66% of the radius of the annular cutting edge. The cutting element may be extendable through the window during operation such that as the cutting element is being rotated about its longitudinal axis, less than an entire radial portion of the leading radial wall passes through the window. A plurality of abrading members may be formed on at least the central portion of the inner surface of the cutting element to abrade hardened tissue as the cutting element is rotating about its longitudinal axis. A radially outermost portion of the leading radial edge of the raised element may be spaced apart radially from an inner surface of the cutting element.