Variable-Section Helical Fixation for Cardiac Anchoring

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Solution Overview

Problem

The constant round diameter of helical fixation elements in implantable medical devices limits their coupling and anchoring performance, longevity, and causes tissue trauma.

Innovation Solution

A helical fixation element with varying cross-sectional dimensions along its length, featuring a stiff distal end for tissue piercing and a flexible intermediate section for maneuverability, and optionally including asymmetrical cross-sections and additional features like barbs or openings for enhanced anchoring and tissue integration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a constant round diameter wire is used for the helical fixation element, then the manufacturing process is simple, but the coupling and anchoring performance is limited and tissue trauma occurs

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidcoupling and anchoring performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The fixation element incorporates varying cross-sectional dimensions along its length, with the distal portion having a smaller cross-sectional dimension than the proximal portion. This local variation in geometry allows the distal end to be more flexible for maneuvering through tissue while the proximal end maintains sufficient stiffness for anchoring to the device body, thereby improving coupling and anchoring performance without compromising manufacturing feasibility

Inventive Principle:

Principle #3Local quality

2Strength

If the helical fixation element is stiff for robust attachment, then anchoring strength is improved, but maneuverability and ease of delivery are reduced

Engineering Contradiction:

Improveanchoring strengthVSAvoidmaneuverability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The fixation element features a non-uniform cross-sectional dimension along its length, with the distal portion having a smaller cross-sectional dimension than the proximal portion. This creates a gradient of mechanical properties where the proximal end remains stiff for robust anchoring to the device body while the distal end becomes more flexible for easier maneuvering during delivery and deployment

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The fixation element is divided into distinct sections with different cross-sectional dimensions - a proximal section with larger dimensions for strength and a distal section with smaller dimensions for flexibility. This segmentation allows each portion to be optimized for its specific function while maintaining structural integrity across the entire element

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If the helical fixation element has uniform cross-section, then manufacturing is easier, but long-term integrity and fatigue performance are compromised

Engineering Contradiction:

Improvemanufacturing easeVSAvoidlong-term integrity

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The fixation element incorporates varying cross-sectional dimensions along its length, with the proximal portion having larger dimensions to provide robust anchoring and resistance to fatigue from device movement, while the distal portion has smaller dimensions for flexibility. This localized variation in geometry optimizes both long-term integrity at the anchoring point and maneuverability at the tissue interface

Inventive Principle:

Principle #3Local quality

4Ease of operation

If the fixation element is flexible for ease of maneuvering, then delivery is easier, but anchoring strength and robust attachment are reduced

Engineering Contradiction:

Improveease of maneuveringVSAvoidanchoring strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The fixation element features a non-uniform cross-sectional dimension along its length, with the distal portion having a smaller cross-sectional dimension than the proximal portion. This creates a gradient of mechanical properties where the proximal end maintains sufficient stiffness for strong anchoring while the distal end becomes more flexible for easier maneuvering during delivery

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250319304A1Implantable apparatus having helix fixation with varying cross-section

Publication Date: 2025.10.16 MEDTRONIC INC

AI summary

A medical device, and methods of manufacturing the same, including a fixation element having varied cross-sectional dimension. The device including a body portion and the fixation element coupled to a distal body end and extending therefrom. The fixation element is configured to affix the body portion to a wall of a heart. The fixation element defines a helical shape extending between a distal fixation end and a proximal fixation end along a direction of a helical axis. The fixation element defines a proximal fixation section proximate the proximal fixation end, a distal fixation section proximate the distal fixation end, and a middle fixation section located between the proximal and distal fixation sections. A cross-sectional dimension of the middle fixation section is smaller than a cross-sectional dimension of the proximal fixation section.