Intravascular Catheter With Helical Slits and Threaded Tip

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Solution Overview

Problem

Existing interventional cardiology devices face challenges in passing larger devices like stents or balloons through vascular stenosis without dislodging emboli, and they often experience uneven torque transmission due to flexible materials, leading to kinking and inadequate navigation through tortuous blood vessels.

Innovation Solution

A small-diameter intravascular catheter with a threaded tip and helically slitted wall, made from rigid materials like Nitinol or stainless steel, that applies torque to deform stenotic lesions rather than abrade them, allowing for even torque transmission and flexibility to navigate complex vessels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible materials are used to navigate tortuous blood vessels, then the catheter can navigate complex vessels, but torque transmission becomes uneven leading to kinking

Engineering Contradiction:

Improveflexibility to navigate tortuous vesselsVSAvoidtorque transmission uniformity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The catheter is divided into distinct functional segments: a flexible proximal portion for navigation and a rigid distal portion with threaded tip for torque transmission. This segmentation allows each part to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the catheter have different mechanical properties - the proximal end is flexible for navigation while the distal end is rigid for reliable torque transmission. This local differentiation resolves the contradiction between overall flexibility and localized torque transmission reliability.

Inventive Principle:

Principle #3Local quality

2Volume of moving object

If auger-like devices are used to debulk lesions, then the lumen size increases, but emboli are dislodged into circulation

Engineering Contradiction:

Improvelumen sizeVSAvoidemboli formation

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

Instead of removing material (auger approach), the invention inverts the approach by using a threaded tip to engage and pull through the lesion, deforming it plastically to create a passage. This constructive approach expands the lumen without dislodging emboli.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The threaded tip converts the harmful resistance of the stenotic lesion into a beneficial plastic deformation that creates a stable passage. The lesion's resistance is overcome constructively by the screwing motion, transforming the obstacle into a remodeled structure with improved flow.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If rigid materials are used for torque transmission, then torque is transmitted evenly, but flexibility to navigate vessels is reduced

Engineering Contradiction:

Improvetorque transmissionVSAvoidflexibility for navigation

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The catheter is segmented into a flexible proximal portion for navigation and a rigid distal portion for torque transmission. This allows the rigid material to provide reliable torque transmission while the flexible portion maintains navigability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The catheter design transitions from a one-dimensional uniform structure to a multi-dimensional gradient structure where material properties change along the longitudinal axis. This dimensional variation in material rigidity resolves the contradiction between overall flexibility and torque transmission reliability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 catheter effectively passes larger devices through stenotic lesions with minimal torsional displacement and emboli formation, providing a smoother lumen and reduced risk of turbulence, while maintaining flexibility and preventing kinking.

Implementation Method 1

the passage of the screw threads through the lesion creates a plastic deformation of the lesion

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the slits have a pattern geometry that limits torsional displacement and may include areas of sigmoid curves periodically spaced along the longitudinal length of the slit portion of the catheter

Methodology Applied

Scientific EffectTorsional displacement: Torque

Data Source

PatentUS7981091B2Small diameter intravascular catheter with screw tip and limited torsional displacement

Publication Date: 2011.07.19 TELEFLEX LIFE SCIENCES LLC

AI summary

A catheter to be passed over a guidewire, including a screw portion with a cylindrical hollow shaft and a helical thread portion extending outwardly from the hollow shaft. The screw portion is secured coaxially to a tubular portion formed from a substantially rigid material. The tubular portion has, along a portion of its length, at least two slits having a pattern geometry that limits torsional displacement. The catheter also includes a hub having a lumen joined substantially coaxially to the tubular portion.