Braid-Free Triple-Coil Microcatheters for Lesion Crossability

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Solution Overview

Problem

Existing microcatheters face challenges in achieving a desirable combination of small crossing profiles, optimal flexibility, effective torque transmissibility, and bi-directional torque response, particularly in navigating complex vasculature such as the coronary and peripheral vasculature.

Innovation Solution

The microcatheter design incorporates a triple-coil assembly with alternating winding directions and gaps between filar groups, combined with a polymer layer that decreases in hardness from proximal to distal, enhancing flexibility and torque transmission while maintaining axial force transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If microcatheters are designed with high flexibility to traverse tortuous vasculature, then they can navigate complex vascular paths, but they lose pushability and torque transmission capability

Engineering Contradiction:

ImproveflexibilityVSAvoidpushability

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The catheter is divided into multiple segments with different flexibility characteristics. The proximal portion has higher flexibility for navigating tortuous paths, while the distal portion maintains sufficient rigidity for pushability and torque transmission. This segmentation allows each portion to optimize its mechanical properties for its specific functional requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the catheter are assigned different mechanical properties. The proximal section is designed with higher flexibility to navigate complex vasculature, while the distal section maintains greater rigidity for effective lesion crossing and device delivery. This local differentiation resolves the contradiction by allowing flexibility where needed without compromising pushability where required.

Inventive Principle:

Principle #3Local quality

2Area of moving object

If microcatheters are designed with small crossing profiles to access peripheral vessels, then they can traverse narrow vasculature, but they reduce torque transmissibility and pushability

Engineering Contradiction:

Improvecrossing profileVSAvoidtorque transmissibility

Core Design Contradiction:

Area of moving objectVSForce

Solution Approach 1:

The catheter structure is segmented into proximal and distal portions with differentiated wall thicknesses and material properties. The distal portion maintains a small outer diameter for crossing narrow vessels while the proximal portion has increased structural support for torque transmission. This segmentation enables the catheter to achieve both small crossing profile and adequate torque transmissibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The catheter employs composite construction with multiple materials having different mechanical properties. The distal portion uses materials optimized for flexibility and small profile, while the proximal portion incorporates materials with higher strength and stiffness for torque transmission. This composite approach allows the catheter to simultaneously achieve small crossing profile and adequate torque transmissibility.

Inventive Principle:

Principle #40Composite materials

3Force

If microcatheters are designed for antegrade access with maximum pushability, then they can reach distant targets, but they lack the flexibility and smaller profile needed for retrograde crossing

Engineering Contradiction:

ImprovepushabilityVSAvoidflexibility

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The catheter is designed with segmented mechanical properties along its length. The proximal portion is optimized for pushability with higher structural support, while the distal portion is optimized for flexibility with reduced wall thickness and increased compliance. This segmentation enables the catheter to function effectively in both antegrade and retrograde configurations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The catheter is designed to perform multiple functions: it can be used for both antegrade and retrograde access, and can navigate both tortuous and straight vascular paths. The differentiated proximal and distal sections enable this multi-functionality, allowing the same catheter to optimize performance for different procedural requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250332380A1High performance braid-free microcatheters with improved vasculature and lesion crossability characteristics and response

Publication Date: 2025.10.30 CARDIOVASCULAR SYSTEMS INC

AI summary

Embodiments of the disclosed microcatheters comprise an inner tube that extends from a distal tip to a proximal hub. One embodiment of a microcatheter comprises a first inner coil wound around a length of the inner tube, a second middle coil wound around the first coil and in a different winding direction or lay than the winding direction or lay of the first coil, and a third outer coil wound around a proximal portion of the second coil and in a different winding direction or lay than the winding direction or lay of the second coil. In one disclosed embodiment, the first, second and third coils include distal ends that terminate distally together at a common location that is spaced proximally from the distal tip. Gaps in one or more of the first, second or third coils may be provided between groups or sections of wire filars forming the coils to improve flexibility while maintaining sufficient axial force transmission and torque capabilities.