Conformable Balloon Anisotropic Stiffness Curved Vessel
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Solution Overview
Problem
Medical angioplasty balloons tend to straighten when inflated in curved vessels, causing unwanted stress and potential damage due to their non-compliance with curved anatomies, leading to kinking and inefficient vessel contact.
Innovation Solution
Development of a semi-compliant to non-compliant medical balloon with a balloon wall material that undergoes significant compressive strain in a curved configuration, featuring a porous microstructure with circumferential stiffness at least 5 times greater than longitudinal stiffness, allowing it to conform to curved vessels without significant straightening force, and constructed using an anisotropic film wrapped at a high angle to form a tubular precursor with a compliant bladder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a non-compliant balloon is used to maintain shape definition during inflation, then the balloon can operate at high angioplasty pressures, but the balloon tends to straighten in curved vessels causing vessel stress and damage
Solution Approach 1:
The balloon wall material's mechanical properties are changed by controlling the balance ratio of its microstructure. The material is engineered to have circumferential stiffness at least 5 times greater than longitudinal stiffness, creating anisotropic mechanical behavior that allows the balloon to conform to curved vessels while maintaining sufficient pressure resistance for angioplasty procedures
Solution Approach 2:
The balloon wall is constructed from a composite material with a controlled porous microstructure. This microstructure consists of interconnected pores with specific size distributions and wall thicknesses, creating a material that combines compliance in the longitudinal direction with stiffness in the circumferential direction, enabling the balloon to simultaneously conform to vessel curvature and resist inflation pressures
2Adaptability or versatility
If a compliant balloon is used to conform to curved vessels, then the balloon can adapt to vessel shape, but the balloon cannot maintain sufficient pressure for effective angioplasty
Solution Approach 1:
The balloon material's mechanical anisotropy is tuned by adjusting the microstructural parameters, specifically the balance ratio between circumferential and longitudinal stiffness. This allows the balloon to exhibit compliant behavior in the longitudinal direction for vessel conformance while maintaining non-compliant behavior in the circumferential direction for pressure resistance
Solution Approach 2:
The balloon wall utilizes a porous microstructure with controlled pore size, distribution, and connectivity. This porous architecture enables the material to deform longitudinally to match vessel curvature while the pore walls provide structural support for circumferential stiffness, allowing the balloon to conform to curved vessels and maintain high inflation pressures simultaneously
3Ease of operation
If a cylindrical balloon is inflated in a curved vessel, then the balloon can be delivered through the vessel, but the balloon kinks and fails to provide uniform vessel contact
Solution Approach 1:
The balloon's mechanical properties are designed to be directionally dependent, allowing it to dynamically adapt its shape during inflation. The anisotropic stiffness enables the balloon to bend and conform to the vessel's curvature rather than maintaining a rigid cylindrical shape, preventing kinking and ensuring uniform contact with the vessel wall throughout the inflation process
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 balloon maintains a kink-free, curved configuration at inflation pressures above 4 atm, providing uniform vessel contact and pressure, reducing vessel straightening and facilitating efficient therapeutic agent delivery or device deployment.
Implementation Method 1
the balloon wall material comprises a circumferential stiffness and a longitudinal stiffness and wherein the circumferential stiffness is at least 5 times greater than the longitudinal stiffness
Implementation Method 2
a balloon wall material having a porous microstructure
Implementation Method 3
a portion of the balloon wall along an inner arc undergoes at least 5% compressive strain when inflated in a curved configuration requiring 20% strain
Data Source
AI summary
The present disclosure is directed toward a semi-compliant to non-compliant, conformable balloon useful in medical applications. Conformable balloons of the present disclosure exhibit a low straightening force when in a curved configuration and at inflation pressures greater than 4 atm. Balloons of the present disclosure are constructed of material that can compress along an inner length when the balloon is in a curved configuration. In further embodiments, balloons of the present disclosure can be constructed of material that sufficiently elongates along an outer arc when the balloon is in a curved configuration. As a result, medical balloons, in accordance with the present disclosure, when inflated in a curved configuration, exhibit kink-free configurations and do not cause a significant degree of vessel straightening.