Counterflexing Steerable Catheter for Precise Mitral Valve Alignment
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Solution Overview
Problem
Existing transvascular techniques for repairing damaged heart valves, such as the mitral valve, are limited by the inability to precisely position and deploy prosthetic devices due to the complex anatomy of the heart, particularly the mitral valve's D-shaped orifice and the challenges of navigating the delivery catheter through the septum to the left atrium.
Innovation Solution
A steerable catheter with a distal and proximal flexible portion, controlled by offset pull wires, allowing for a counterflexing configuration that enables precise positioning and deployment of prosthetic devices by creating a 'question mark' shape, facilitating better alignment with the mitral valve and reducing the gap between the catheter end and the valve annulus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional delivery catheter is used to access the mitral valve through trans-septal technique, then the catheter can be advanced into the left atrium, but the catheter cannot be precisely positioned and aligned with the mitral valve annulus due to the complex anatomy and D-shaped orifice
Solution Approach 1:
The catheter incorporates two flexible portions with pull wires that allow dynamic adjustment of the catheter shape. The first flexible portion can be bent toward the septum while the second flexible portion bends away from the septum, enabling the operator to dynamically adjust the catheter configuration to achieve precise alignment with the mitral valve annulus in different anatomical scenarios
Solution Approach 2:
The catheter is designed with offset pull wires that create a curved or counterflexing configuration when actuated. This curvature allows the catheter to navigate the complex anatomical path from the septum to the mitral valve and align with the D-shaped orifice, transforming a straight catheter into a curved delivery system that matches the anatomical geometry
2Adaptability or versatility
If the delivery catheter is made more flexible to navigate the heart anatomy, then the catheter can access the mitral valve, but the catheter loses stability and precision in positioning
Solution Approach 1:
The catheter is divided into two distinct flexible portions separated by a rigid or less flexible middle section. The first flexible portion (distal to the middle portion) and second flexible portion (proximal to the middle portion) can be independently actuated by separate pull wires, allowing each segment to adapt to different anatomical requirements while the middle portion provides structural stability and positioning reference
Solution Approach 2:
Different portions of the catheter have different mechanical properties. The flexible portions contain radial slots or grooves that allow bending in specific directions when pull wires are actuated, while the middle portion maintains greater rigidity. This local differentiation enables the catheter to be flexible where needed for navigation while maintaining stability for precise positioning
3Measurement precision
If offset pull wires are used to create counterflexing configuration, then the catheter can align with the mitral valve annulus, but the device complexity increases
Solution Approach 1:
The steering function is extracted from the entire catheter structure and concentrated in two specific flexible portions with dedicated pull wires. This allows the offset bending mechanism to be localized to specific segments rather than requiring complex mechanisms throughout the entire catheter, simplifying the overall design while achieving the desired alignment capability
Solution Approach 2:
The pull wires are nested within the catheter structure, running through the flexible portions and middle section. The first pull wire is associated with the first flexible portion and the second pull wire with the second flexible portion, creating a nested configuration where control elements are integrated within the catheter wall rather than externally attached
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
Enhances the ability to accurately position and deploy prosthetic devices at the mitral valve, reducing procedural complexity and improving the efficacy of valve repair by minimizing regurgitation through better alignment and spacing adjustments.
Implementation Method 1
A first pull wire may attach to the middle portion such that applying tension to the first pull wire causes the first flexible portion to bend in a first bend direction. A second pull wire may attach to the distal end such that applying tension to the second pull wire causes the second flexible portion to bend in a second bend direction.
Data Source
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AI summary
An implantable prosthetic device includes a flexible hollow tube extending from a proximal end to a distal end. A first flexible portion extends from the proximal end to a middle portion. A second flexible portion extends from the middle portion to the distal end. A first pull wire attaches to the middle portion such that applying tension to the first pull wire causes the first flexible portion to bend in a first bend direction. A second pull wire attaches to the distal end such that applying tension to the second pull wire causes the second flexible portion to bend in a second bend direction. The first bend direction is offset from the second bend direction by about 160 to about 200 degrees.