Multilayer Balloon Catheter with Integral Shaft
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Solution Overview
Problem
Balloon catheters used in medical procedures face challenges due to the need for high trackability, thin-walled yet strong balloons in small, tortuous vessels, where existing technologies fail to consistently provide sufficient burst strength and controlled distension within the required pressure ranges.
Innovation Solution
A multilayer shaft with an integral balloon formed from a polymeric tube, featuring an outer layer of poly(ether-block-amide) and an inner layer of nylon, with a specific manufacturing process involving multiple stretching and heat-setting steps to achieve a burst strength of at least 30,000 psi and controlled distension per atmosphere, and a balloon catheter design incorporating this shaft with a guidewire lumen and manifold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the balloon wall is made thinner to improve trackability and reduce profile, then the burst strength and structural integrity deteriorate
Solution Approach 1:
The balloon is constructed with a multilayer composite structure consisting of an inner layer, middle layer, and outer layer made from different polymeric materials. Each layer contributes specific properties: the inner layer provides flexibility and trackability, the middle layer provides reinforcement and burst strength, and the outer layer provides durability and controlled distension. This composite structure enables the balloon to achieve both thin-wall design for trackability and high burst strength simultaneously.
2Ease of operation
If the balloon wall is made thinner to reduce profile and improve navigation, then the controlled distension capability deteriorates
Solution Approach 1:
The multilayer composite structure with specific material selections and thickness ratios enables controlled distension while maintaining thin overall profile. The different polymeric layers have different elastic moduli and expansion characteristics, allowing the balloon to expand in a controlled, predictable manner during inflation while remaining navigable through tortuous vasculature.
3Strength
If multilayer construction is used to improve burst strength, then the device complexity increases
Solution Approach 1:
The multilayer balloon is formed as an integral structure from a single extruded tubular preform, merging multiple functional layers into one unified manufacturing process. The coextrusion technique creates the multilayer structure in a single step, and the subsequent forming process shapes all layers simultaneously into the final balloon geometry, eliminating the need for separate assembly steps and reducing overall device complexity despite the multilayer construction.
4Strength
If the balloon is made with high burst strength materials, then the trackability and flexibility deteriorate
Solution Approach 1:
The inner layer is constructed from a soft, flexible polymer material that provides trackability and navigability through tortuous vessels, while the middle and outer layers use stronger polymeric materials that provide burst strength and structural integrity. This gradient structure optimizes both trackability and strength without compromise.
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 solution provides a balloon catheter with enhanced burst strength and controlled distension, suitable for demanding medical procedures, ensuring effective navigation and treatment in small, tortuous vessels while maintaining structural integrity and trackability.
Implementation Method 1
a first stretching step wherein a portion of a distal end region of an extruded multilayer polymeric tube is stretched at a first pressure and a first temperature
Implementation Method 2
heat-setting steps to achieve a burst strength of at least 30,000 psi and controlled distension per atmosphere
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Ballon catheter (20) with a multilayer shaft (22) with integral balloon (24) and a total length of at least 70 cm and method of forming the multilayer shaft comprising: a first stretching step wherein a portion of a distal end region of a multilayer polymeric tube is stretched at a first pressure and a first temperature, and the first pressure is equal to ambient pressure; a second stretching step wherein the multilayer polymeric tube is stretched at a second pressure and the first temperature until the desired final length, and the second pressure is greater than the first pressure; a third stretching step wherein the multilayer polymeric tube is stretched at a third pressure and the first temperature having a final stretched length, and the third pressure is less than the second pressure and greater than the first pressure; and a balloon forming step.