Nested Catheter System with Shape Memory Anchoring for Guidewire Control
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Solution Overview
Problem
Current guidewire insertion techniques for heart valve procedures face challenges due to limited 2D imaging, lack of control over catheter direction and stability, especially in large calibre blood vessels like the aorta, and risk of damaging tissues with flexible guidewires.
Innovation Solution
A device comprising three catheters with distinct characteristics, where the intermediate catheter has a shape-memory anchoring element that expands to secure within the blood vessel and the inner catheter can be curved and oriented to precisely direct the guidewire through the heart valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single catheter is used for guidewire insertion, then the device complexity is low, but the control over catheter direction and stability is insufficient
Solution Approach 1:
The catheter system is divided into three distinct catheters (outermost catheter, intermediate catheter, innermost catheter), each with specific functions. The outermost catheter provides initial guidance, the intermediate catheter offers stable positioning with anchoring elements, and the innermost catheter enables precise guidewire direction. This segmentation allows independent optimization of each component's characteristics.
Solution Approach 2:
The three catheters are inserted concentrically within each other, creating a nested structure. The intermediate catheter is inserted into the outermost catheter, and the innermost catheter is inserted into the intermediate catheter. This nesting allows compact storage while enabling sequential deployment of functional layers.
2Reliability
If a flexible guidewire is used to avoid tissue damage, then the safety is improved, but the guidewire bends easily and cannot maintain straight position
Solution Approach 1:
The intermediate catheter acts as a mediator between the flexible guidewire and the rigid anchoring elements. It provides a stable lumen that guides the flexible guidewire while maintaining its own position through shape-memory anchoring elements, allowing the guidewire to remain relatively straight without direct contact with rigid structures.
Solution Approach 2:
The anchoring elements utilize shape-memory material that changes its physical state in response to temperature or stress, allowing it to transition between a compressed state (for insertion) and an expanded state (for anchoring). This parameter change enables the anchoring elements to securely grip the blood vessel wall while maintaining guidewire flexibility.
3Measurement precision
If 2D imaging is used for guidewire insertion, then the equipment complexity is low, but the positioning precision is insufficient
Solution Approach 1:
The device incorporates radiopaque markers and contrast agents that provide real-time visual feedback during the procedure. The intermediate catheter's anchoring elements and the innermost catheter's curved configuration can be visualized under fluoroscopy, allowing the operator to adjust positioning based on immediate imaging feedback to achieve precise guidewire placement.
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
Enables stable, controlled, and repeatable guidewire insertion with reduced risk of tissue damage, allowing precise positioning and orientation of the guidewire within the heart valve.
Implementation Method 1
The wire elements are made of a shape memory material and are configured to spontaneously bend away radially with respect to the tube to abut against the inner walls of the blood vessel
Implementation Method 2
The apical portion the innermost catheter is configured to assume a curved position at rest, and is configured to be elastically extended when inserted into the tube of the intermediate catheter and to spontaneously return to the curved position at rest as it exits from the tube
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
This disclosure provides a device comprising an outermost catheter (1), an intermediate catheter (2) inserted into the outermost catheter (1), a innermost catheter inserted into the intermediate catheter (2) configured to accurately control and reproducibly guide a wire through a heart valve. The intermediate catheter (2) has an apical portion (6) that defines a tube onto which an anchoring element for anchoring to inner walls of a blood vessel slides, the anchoring element comprises an annular slider (4) and a plurality of wire elements (5) each having a proximal end fixed to the tube (6) and a distal end fixed to the annular slider (4), wherein said wire elements (5) are made of a shape memory material. At least an apical portion of the inner catheter is configured to assume a curved shape at rest, as far as it protrudes out of the tube (6).