Catheter Distal Tip Geometry and Coating for Hard Lesions

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Solution Overview

Problem

Existing catheters face difficulties in easily passing through hard lesions while minimizing damage to the catheter and blood vessels.

Innovation Solution

The catheter design incorporates a distal tip with an enlarged diameter portion and a tapered or curved shape, along with a resilient coating, to reduce contact area and enhance pushability and flexibility, thereby facilitating passage through hard lesions and protecting blood vessels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal distal tip is used to pass through hard lesion sites, then the catheter can penetrate hard lesions, but the catheter may be damaged during passage

Engineering Contradiction:

ImprovepenetrabilityVSAvoidcatheter damage risk

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The distal tip is covered with a flexible resin coating layer that allows the catheter to bend and conform to the vessel wall shape, reducing stress concentration and preventing damage to both the catheter and blood vessels during passage through hard lesions

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The distal tip combines a metal core (for structural strength and penetrability) with a resin coating layer (for flexibility and protection), creating a composite structure that achieves both penetration capability and damage prevention

Inventive Principle:

Principle #40Composite materials

2Strength

If the catheter is made rigid to pass through hard lesions, then penetrability is improved, but the catheter becomes difficult to manipulate and position

Engineering Contradiction:

ImproverigidityVSAvoidmanipulability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The resin coating layer is applied selectively to the distal tip portion of the catheter, providing flexibility and followability only where needed for navigation through tortuous vessels, while the proximal portion maintains its rigid metal structure for manipulation and positioning

Inventive Principle:

Principle #3Local quality

3Strength

If the distal tip has a large diameter for strength, then structural integrity is improved, but the contact area with the lesion increases causing damage

Engineering Contradiction:

Improvestructural integrityVSAvoidcontact area damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The resin coating layer acts as a flexible protective shell that reduces the effective contact area between the distal tip and the lesion, allowing the underlying metal structure to maintain strength while the coating minimizes mechanical damage to the vessel wall

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentEP4176918B1catheter

Publication Date: 2025.08.27 ASAHI INTECC CO LTD

Figure 1~2
Figure 3~4
Figure 5(A)~5(B)

AI summary

Provided is a catheter suitable for passing through a hard site. A catheter 1 includes a hollow shaft 10 and a metal distal tip 30 connected to a distal end of the shaft 10. The distal tip 30 includes, between a distal end of the distal tip 30 and the distal end of the shaft 10, an enlarged diameter portion 33 where an outer diameter in a direction perpendicular to an axial direction of the shaft 10 is largest, and an outer diameter DT1 of the enlarged diameter portion 33 is larger than an outer diameter DS of the distal end of the shaft 10. An outer shape of the distal tip sandwiching the enlarged diameter portion between a distal and a proximal end side may be formed as a curved surface with gradually changing inclination. The distal tip may have an outer shape between the enlarged diameter portion and the distal end of the shaft 10 that is outwardly concave.