Segmented Guidewire for Occlusion Crossing
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Solution Overview
Problem
Current guidewires face challenges in successfully crossing total or near-total occlusions in blood vessels due to kinking or vessel wall perforation, limiting the effectiveness of minimally invasive treatments for conditions like coronary chronic total occlusion (CTO).
Innovation Solution
A guidewire design featuring a core member with varying flexibility and stiffness characteristics, including a distal end portion with a first segment that encourages predictable elastic prolapse without kinking, and a jacket member to prevent vessel wall perforation, allowing safe passage through or around occlusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a regular stiffness guidewire is used, then the guidewire can be advanced through soft occlusive matter, but it may kink or exhibit plastic deformation when strong pushing force is applied
Solution Approach 1:
The guidewire is divided into multiple segments with different stiffness characteristics: a distal tip segment (0.5-2 cm) with lower stiffness for navigation, an intermediate segment (2-5 cm) with moderate stiffness, and a proximal segment (5-20 cm) with higher stiffness for force transmission. This segmentation allows the guidewire to advance through occlusions without kinking while maintaining structural integrity.
Solution Approach 2:
Different portions of the guidewire are assigned different mechanical properties: the distal tip is made more flexible with a smaller outer diameter (0.008-0.012 inches) and lower stiffness to navigate occlusions, while the proximal portion is made stiffer with a larger outer diameter (0.014-0.018 inches) to transmit pushing forces without deforming. This local differentiation resolves the contradiction between ease of advancement and structural reliability.
2Reliability
If a high stiffness guidewire is used, then the guidewire can pass through hard or calcified occlusions without kinking, but it may perforate the vessel wall
Solution Approach 1:
The guidewire is segmented into a soft distal tip segment (0.5-2 cm from distal end) with lower stiffness to contact and navigate the occlusion, and a stiffer proximal segment for force transmission. This allows the soft tip to penetrate hard occlusions while the stiff proximal portion provides the necessary pushing force without directly contacting the vessel wall, reducing perforation risk.
Solution Approach 2:
The distal tip is designed with locally different properties: smaller outer diameter (0.008-0.012 inches), lower stiffness, and potentially a tapered shape to concentrate force on the occlusion while distributing contact pressure on the vessel wall. This local softness at the tip reduces vessel wall perforation risk while maintaining overall penetration capability through the harder occlusion material.
3Object-affected harmful factors
If the guidewire distal tip is made softer to reduce vessel wall perforation risk, then safety is improved, but the guidewire may kink when strong pushing force is applied
Solution Approach 1:
The guidewire is divided into at least three segments: a distal tip segment (0.5-2 cm) with lower stiffness for safety, an intermediate segment (2-5 cm) with moderate stiffness, and a proximal segment (5-20 cm) with higher stiffness for force transmission. This multi-segment design allows the soft distal tip to reduce perforation risk while the stiffer proximal and intermediate segments prevent kinking during forceful advancement.
Solution Approach 2:
The guidewire exhibits a gradient of mechanical properties along its length: the distal tip has locally reduced stiffness and smaller diameter for safety, while the proximal portion has increased stiffness for structural support. This local differentiation allows the soft tip to protect against perforation while the harder proximal sections resist kinking under pushing forces.
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 guidewire design enables safe and effective crossing of occlusions with reduced risk of kinking or vessel wall perforation, facilitating minimally invasive treatments by providing atraumatic navigation and sufficient stiffness for hard occlusions.
Implementation Method 1
The first segment can be designed to encourage predictable, elastic prolapse without kinking during use
Data Source
AI summary
Guidewires and related methods for percutaneous crossing of an occlusion in a blood vessel are disclosed. A guidewire can include a core member and a jacket member. The core member can extend from a proximal end portion to a distal end portion, with the distal end portion including a first segment, a more distal second segment and a more proximal third segment. The first segment can be configured to encourage prolapse by way of a short taper or a diameter-reduced portion. The jacket member can surround at least the distal end portion of the core member. A method can include advancing a distal end portion of the guidewire through the natural lumen of a blood vessel to a location near an occlusion. A longitudinal pushing force can be applied to a proximal end portion of the guidewire, thereby causing a first segment of the distal end portion to prolapse.