Guidewire With Variable Coil Pitch Sections

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Solution Overview

Problem

Conventional guide wires experience a decrease in rotational followability when curved due to coil squeezing and contact between the coil body and core shaft, leading to reduced effectiveness in navigating complex vascular pathways.

Innovation Solution

A guide wire design featuring a sparsely wound coil portion with a sparse coil pitch between the distal-end and proximal-end joining regions, along with closely wound portions and resin coatings on specific segments, to prevent coil squeezing and maintain rotational followability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the coil body is wound densely to maintain structural integrity, then the guide wire has sufficient strength, but the rotational followability decreases due to coil squeezing when curved

Engineering Contradiction:

Improvestructural integrityVSAvoidrotational followability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The coil body is designed with non-uniform winding density, featuring a sparsely wound portion at the distal end and closely wound portions at the proximal end. This local variation in coil pitch allows the distal end to expand and rotate freely while maintaining structural integrity through the densely wound proximal portion.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The coil body is divided into distinct segments with different winding characteristics: a sparsely wound distal portion and closely wound proximal portions. This segmentation enables different regions to perform different functions - the sparsely wound region provides rotational freedom while the closely wound region maintains structural strength.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the coil body is made flexible to improve rotational followability, then the guide wire can navigate curved pathways, but the slidability decreases due to increased friction

Engineering Contradiction:

Improverotational followabilityVSAvoidslidability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The coil body features localized variation in winding density with a sparsely wound distal portion that provides flexibility for navigation and closely wound proximal portions that maintain slidability. The resin coating is also selectively applied to specific segments to optimize surface properties for reduced friction.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The coil pitch parameter is varied along the length of the guide wire, transitioning from sparse winding at the distal end to close winding at the proximal end. This parameter change allows the guide wire to achieve both flexibility for navigation and low friction for slidability in different regions.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If the coil body is designed with uniform winding pitch, then the manufacturing process is simple, but the rotational followability deteriorates when the guide wire is curved

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidrotational followability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The coil body employs non-uniform winding density with a sparsely wound distal portion and closely wound proximal portions. This local quality variation resolves the technical contradiction by allowing the distal end to expand and rotate freely when curved, while the proximal end maintains structural integrity through denser winding.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The coil body is segmented into distinct regions with different winding characteristics. The sparsely wound distal segment provides rotational freedom while the closely wound proximal segments maintain structural strength, thereby improving rotational followability without significantly complicating the manufacturing process.

Inventive Principle:

Principle #1Segmentation

4Volume of moving object

If the coil body is compressed to reduce the overall size, then the guide wire becomes more compact, but the rotational followability decreases due to coil squeezing

Engineering Contradiction:

Improveoverall sizeVSAvoidrotational followability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The coil body features localized variation in winding density, with the distal end having a sparser pitch that allows expansion and rotation. This local quality design enables the guide wire to maintain a compact overall size while preserving rotational followability at the distal end through the sparsely wound portion's ability to expand.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11400262B2Guidewire having external coil with sections of different winding pitches and resin coatings

Publication Date: 2022.08.02 ASAHI INTECC CO LTD

AI summary

A guide wire includes a core shaft, a coil wound around the core shaft, a distal-end joining region to which a distal end of the core shaft and a distal end of the coil are joined, and a proximal-end joining region to which a proximal end of the core shaft and a proximal end of the coil are joined, and the coil has a sparsely wound portion having a sparser coil pitch than other portions of the coil, the sparsely wound portion being disposed between the distal-end joining region and the proximal-end joining region.