Dual-Layer Balloon Design for Burst Strength and Diameter Control
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Solution Overview
Problem
Expandable medical balloons face challenges in achieving a balance of physical properties such as high strength, inelasticity, and predictable inflation in small, tortuous vessels, particularly in peripheral vasculature, where burst pressure reduction and micro-tearing occur due to localized stress, making it difficult to treat lesions effectively.
Innovation Solution
The development of an expandable medical balloon with a coextruded structure featuring a first balloon layer of polyethylene terephthalate with a higher intrinsic viscosity as the outer layer and a second layer with a lower intrinsic viscosity as the inner layer, providing a balloon-in-balloon construction with specific hoop ratios and burst strength, and a method for forming this balloon using coextruded tubes with different polyethylene terephthalate layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single layer balloon design is used, then the balloon structure is simple, but the burst strength is insufficient and micro-tearing occurs in peripheral vasculature
Solution Approach 1:
The patent employs a dual-layer balloon construction where the first layer comprises a base structural material (such as polyethylene terephthalate or nylon) providing fundamental strength, and the second layer comprises a different polymeric material (such as polyurethane or elastomer) providing enhanced burst strength and elasticity. This composite structure allows the balloon to withstand higher pressures and resist micro-tearing in peripheral vasculature while maintaining a manageable structural complexity through co-extrusion or lamination processes.
2Strength
If the balloon wall is made thin to reduce profile, then the balloon is more flexible, but the burst strength and hoop strength are reduced
Solution Approach 1:
The dual-layer construction allows each layer to be optimized for specific functions: the base structural layer provides foundational hoop strength, while the second layer adds burst strength without proportionally increasing wall thickness. This enables thin-walled balloons to maintain high strength characteristics through material composition rather than relying solely on increased thickness.
3Ease of operation
If the balloon is made inelastic to control diameter, then the diameter control is precise, but the ability to vary diameter for different lesions is reduced
Solution Approach 1:
The second layer of the dual-layer balloon is formulated with specific elastic properties that allow controlled diameter variation in response to pressure changes and thermal expansion during the procedure. This enables the balloon to maintain relative inelasticity for precise diameter control during inflation while still providing sufficient elasticity to adapt to different lesion sizes and vessel diameters, achieving a balance between control and adaptability.
Data Source
Figure 1
AI summary
An expandable medical balloon, the expandable medical balloon comprising a first balloon wall, the first balloon wall comprising a first balloon layer of polyethylene terephthalate having a first intrinsic viscosity, the first layer is outer to a second layer of polyethylene terephthalate, the second balloon layer of polyethylene terephthalate having a second intrinsic viscosity, the second layer is an inner layer, wherein the intrinsic viscosity of the first balloon layer is higher than the intrinsic viscosity of the second balloon layer by about 0.05 dl/g or more.