Non-Circular Stents for Cyclic Vessel Compliance Restoration
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Solution Overview
Problem
Insufficient compliance in blood vessels, such as the aorta, leads to reduced perfusion and cardiac output, resulting in health complications.
Innovation Solution
Stents designed to cyclically reshape blood vessels between circular and non-circular shapes, transitioning between high and low-pressure phases of the cardiac cycle to enhance compliance without requiring stretching of the vessel walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional circular stents are used to support blood vessels, then vessel structural support is provided, but compliance restoration is limited due to inability to cyclically reshape the vessel
Solution Approach 1:
The stent is designed with non-circular cross-sectional geometry that enables dynamic cyclic transformation between different shapes (e.g., circular to oval) in response to cardiac cycle pressure variations. This dynamic behavior allows the stent to actively reshape the blood vessel, restoring compliance by creating volume changes that mimic natural physiological function rather than providing static support.
2Productivity
If the stent is designed to cyclically reshape the blood vessel, then compliance and blood flow are improved, but device complexity increases due to non-circular geometry and reshaping mechanisms
Solution Approach 1:
The stent employs non-circular asymmetric cross-sectional geometry (such as oval or peanut shapes) to enable effective cyclic reshaping. This asymmetric design creates differential radial forces during pressure cycling, allowing the stent to efficiently change vessel volume and improve blood flow dynamics without requiring complex mechanical actuation systems.
Solution Approach 2:
The stent utilizes changes in geometric parameters (cross-sectional shape, area, and orientation) in response to pressure variations to achieve compliance restoration. By designing the stent structure to naturally transform between different geometric states under physiological pressure cycling, complex mechanical mechanisms are avoided while maintaining effective reshaping capability.
3Productivity
If the stent transitions between circular and non-circular shapes, then vessel volume is adjusted to improve perfusion, but manufacturing precision requirements increase
Solution Approach 1:
The stent design incorporates smooth curved transitions between circular and non-circular cross-sectional shapes, avoiding sharp angles or complex geometric features. This curvature-based approach simplifies manufacturing while enabling effective shape transformation, as the continuous curved geometry can be more easily formed using conventional stent fabrication techniques such as laser cutting or molding.
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
Improves cardiac perfusion by adjusting the cross-sectional area of the blood vessel to match changing pressure conditions, enhancing compliance and reducing pulsatile load.
Implementation Method 1
stents designed to cyclically reshape a target blood vessel segment in a manner as to affect blood flow therein. Such stents, and/or portions thereof, can be configured to transition between circular and non-circular (e.g., oval) shapes
Data Source
AI summary
An implant device includes a unitary stent frame including a first axial end segment having a circular cross-sectional shape, a second axial end segment having a circular cross-sectional shape, and a medial segment disposed between the first axial end segment and the second axial end segment, the medial segment having an oval cross-sectional shape. A fluid-tight covering can be disposed on minor-axis sidewall portions of the medial segment of the stent frame.