Lead Screw Dilator for Expandable Sheath Push Force Reduction

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Solution Overview

Problem

Existing introducer sheaths require high push forces to introduce and advance prosthetic devices due to strain relief portions that resist expansion, leading to potential vessel trauma and damage, and recent trends in thicker prosthetic valves exacerbate this issue.

Innovation Solution

A radially expandable sheath system with a tubular strain relief layer and a dilator that adjusts length via rotational movement, allowing for reduced push forces and controlled expansion of the sheath, minimizing vessel trauma and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a strain relief portion is added to the sheath to ensure hemostasis and protect the vessel, then vessel protection and hemostasis are improved, but push force requirements increase leading to potential vessel trauma

Engineering Contradiction:

ImprovehemostasisVSAvoidvessel trauma

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The strain relief portion is designed to be dynamically expandable rather than rigid. The sheath can transition between a compressed delivery configuration and an expanded delivery configuration, allowing the strain relief portion to adapt its properties during the procedure. This dynamic behavior reduces resistance to device advancement while maintaining hemostatic function.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The sheath changes its physical parameters (diameter, radial stiffness) between compressed and expanded states. In the compressed state, the sheath has smaller diameter and lower profile for delivery. In the expanded state, the sheath achieves larger diameter and higher radial strength to reduce push forces and minimize vessel trauma during device advancement.

Inventive Principle:

Principle #35Parameter changes

2Length of moving object

If the sheath is kept in a compressed state to reduce profile, then ease of delivery is improved, but push forces required to advance the device increase causing vessel trauma

Engineering Contradiction:

Improvesheath profileVSAvoidvessel trauma

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The sheath transitions from a compressed delivery configuration with reduced profile to an expanded delivery configuration with increased diameter. This dynamic transformation allows the sheath to optimize its properties for different phases of the procedure: low profile during insertion, high strength during device advancement.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The sheath is pre-configured in a compressed state for delivery, then expanded at the target site before device advancement. This preliminary compression allows the sheath to be delivered through smaller access sites, and the subsequent expansion prepares the sheath to handle device advancement with reduced push forces.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If multiple sheath sizes are used to accommodate different devices, then adaptability is improved, but procedural time increases

Engineering Contradiction:

Improvedevice compatibilityVSAvoidprocedural time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The expandable sheath serves multiple functions with a single device. It can accommodate different device sizes and types by transitioning between compressed and expanded configurations, eliminating the need for multiple sheath sizes. The sheath hub also provides multiple interfaces for coupling different delivery devices.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the functions of multiple sheath sizes into a single expandable sheath. The sheath integrates both the delivery conduit function and the expansion mechanism, allowing it to replace multiple static sheaths with different diameters. The sheath hub merges multiple coupling interfaces into a single component.

Inventive Principle:

Principle #5Merging (Combining)

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 system reduces procedural time, minimizes vessel trauma and sheath damage, and lowers the risk of tears or plaque dislodgement by requiring lower push forces and using a single sheath size, while maintaining effective delivery of prosthetic devices.

Implementation Method 1

a lead screw mechanism (e.g., a threaded knob) is provided that converts rotational movement to linear movement along a longitudinal axis of the dilator

Methodology Applied

Scientific EffectScrew mechanism: Screw

Implementation Method 2

Methodology Applied

Scientific EffectRadial expansion:

Data Source

PatentUS20260061168A1Lead screw driven sheath dilator

Publication Date: 2026.03.05 EDWARDS LIFESCIENCES CORP

AI summary

Various implementations include a sheath system and corresponding dilator. The system includes a radially expandable sheath having an inner layer and a tubular strain relief layer, and a dilator sized and configured to be received within the lumen of the sheath.