Catheter Balloon Fiber-Braid Assembly for High-Pressure Bond Integrity

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Solution Overview

Problem

Existing medical balloons used in angioplasty and stent delivery face challenges in maintaining structural integrity and molecular orientation under high pressures, particularly when bonded to catheter shafts, leading to potential loss of tensile strength and bond integrity.

Innovation Solution

A catheter assembly design featuring a balloon with a cone, waist, and body portion, reinforced by a fiber braid, where the inner surface of the waist is thermally bonded to the catheter shaft and the fiber braid is adhesively bonded to the waist, preserving molecular orientation and enhancing bond strength at the waist portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the balloon is bonded to the catheter shaft using conventional methods, then the balloon can be attached to the shaft, but the bond integrity and structural stability are compromised under high inflation pressures

Engineering Contradiction:
Improvebond integrityVSAvoidstructural stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs a composite construction where a fiber braid (comprising high-strength materials such as stainless steel, nitinol, or shape memory alloys) is integrated with the balloon wall. This composite structure provides enhanced mechanical strength and structural stability to withstand high inflation pressures while maintaining bond integrity with the catheter shaft. The fiber braid acts as a reinforcement layer that distributes stress and prevents bond failure under pressure.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the balloon is expanded to high volumes, then the medical device can be deployed, but the molecular orientation and tensile strength are lost

Engineering Contradiction:
Improvedeployment effectivenessVSAvoidtensile strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent utilizes shape memory alloys or nitinol materials for the fiber braid that exhibit superelasticity and shape memory effects. These materials can undergo large deformations during balloon expansion and then return to their original configuration, maintaining molecular orientation and tensile strength even after high-volume expansion. The material properties are specifically selected to withstand the cyclic loading and unloading during deployment and retrieval.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the fiber braid is thermally bonded to the balloon, then the bond strength is enhanced, but the molecular orientation of the fiber braid is compromised

Engineering Contradiction:
Improvebond strengthVSAvoidmolecular orientation
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent introduces an intermediary adhesive layer between the fiber braid and the balloon wall that provides strong bonding without requiring thermal processing of the fiber braid itself. This adhesive intermediary maintains the molecular orientation and structural integrity of the fiber braid while achieving the necessary bond strength to withstand inflation pressures. The adhesive is specifically selected to be compatible with both the fiber braid material and the balloon wall material.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design maintains bond integrity and structural stability under high inflation pressures, ensuring effective deployment and retrieval of medical devices while preserving the properties of the fiber braid.

Implementation Method 1

an inner surface of the waist portion is thermally bonded to an outer surface of the catheter shaft

Methodology Applied
Scientific EffectThermal bonding: Heating

Implementation Method 2

an inner surface of the fiber braid is adhesively bonded to an outer surface of the waist portion

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3442642B1Method of making a catether assembly
Publication Date: 2025.10.15 BOSTON SCIENTIFIC SCIMED INC
  • EP3442642B1 patent drawingFigure 1
  • EP3442642B1 patent drawingFigure 2
  • EP3442642B1 patent drawingFigure 3

AI summary

Medical devices and methods for making and using medical devices are disclosed. An example medical device may include a catheter. The catheter may include a catheter shaft and a balloon. The balloon may comprise a cone portion, a waist portion, and a body portion. A fiber braid may be disposed along the balloon. An inner surface of the waist portion may be thermally bonded to an outer surface of the catheter shaft and an inner surface of the fiber braid may be adhesively bonded to an outer surface of the waist portion.