Roll-down Vascular Graft with Adjustable Diameter
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Solution Overview
Problem
Current vascular prosthetic devices often lead to complications due to incorrect estimation of graft length and diameter, resulting in kinking, obstruction, tension, and bleeding during vascular surgeries, as they are typically of uniform caliber and length, lacking adjustable features to match native vessel dimensions accurately.
Innovation Solution
A device with a reversible, water-tight attachment mechanism to the aorta or aortic root, allowing for expansion and contraction to visualize and assess the aortic valve, and simulate diastolic conditions using fluid pressurization, with adjustable features like magnetic attachment, cinching mechanisms, and collapsible designs to ensure precise sizing and minimize distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a prosthetic graft of uniform caliber and length is used, then the device is simple to manufacture and install, but it causes kinking, obstruction, and distortion due to incorrect estimation of graft length and diameter
Solution Approach 1:
The prosthetic graft incorporates an expandable section that can transition from a compressed delivery state to an expanded implanted state. This dynamic capability allows the graft to adapt its diameter and length after implantation, ensuring proper sizing and fit without requiring complex pre-sizing procedures or multiple graft sizes, thus maintaining ease of manufacture while improving reliability
Solution Approach 2:
The graft design allows the distal end to be nested within or adjacent to the proximal end in a compressed configuration during delivery, then expand to achieve the desired length and diameter. This nesting principle enables a single graft to provide variable length and caliber adjustment, resolving the contradiction between simple manufacturing and reliable, customized fit
2Length of moving object
If a longer prosthetic graft is used to ensure sufficient length, then connection tension is avoided, but the graft becomes kinked and obstructed due to redundancy
Solution Approach 1:
The expandable graft section allows the device to be delivered in a compact, short configuration and then expanded in situ to the required length. This dynamic length adjustment eliminates redundant material that would cause kinking while ensuring sufficient length to span the vascular defect, resolving the contradiction between adequate length and avoidance of harmful redundancy
Solution Approach 2:
The graft's physical parameters (length and diameter) are changed after implantation through expansion mechanisms. This allows the final graft dimensions to be optimized for the specific anatomical requirements, preventing both kinking from excessive length and tension from insufficient length
3Area of moving object
If a larger diameter prosthetic graft is used to ensure adequate caliber, then flow capacity is improved, but bleeding occurs at the vascular connection site due to size mismatch
Solution Approach 1:
The graft incorporates an expandable section that allows the diameter to be adjusted after implantation. The graft can be delivered with a smaller initial diameter to facilitate connection without bleeding, then expanded in situ to achieve the larger diameter needed for adequate flow capacity, resolving the contradiction between connection safety and flow performance
Solution Approach 2:
The graft diameter parameter is changed dynamically after implantation. The expandable section allows the diameter to be increased from a small delivery size (preventing connection bleeding) to a large functional size (ensuring adequate flow capacity), eliminating the need to choose between these conflicting requirements
4Ease of operation
If a standard uniform graft is used, then the device is easy to handle and manipulate, but it cannot be size-matched to native vessels, leading to distortion and malfunction
Solution Approach 1:
The expandable graft section provides adaptability for size-matching while maintaining ease of handling during delivery. The graft is delivered in a standardized, compact form that is easy to manipulate, then expanded in situ to match the specific dimensions of the native vessels, resolving the contradiction between ease of operation and adaptability
Solution Approach 2:
The expandable graft design creates a universal device that can be used across a wide range of patient anatomies and vessel sizes. A single graft design with expandable capabilities replaces the need for multiple fixed-size grafts, providing both ease of handling (single device type) and adaptability (customizable size)
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
Enables precise visualization and repair of aortic valves under physiologic conditions, reducing complications by allowing repeated assessments and adjustments until a satisfactory result is achieved, while maintaining a compact form for unimpeded access during surgery.
Implementation Method 1
The aortic root is pressurized with fluid, and the aortic valve is visualized
Implementation Method 2
reversible attachment mechanism (e.g., magnetic, external cinching or snaring over a groove or ridge, vacuum or other mechanism)
Data Source
AI summary
A prosthetic device for attachment to a vascular structure includes a body with an axial length configured to be adjustable by manipulation of at least one design feature but not materially affected by simple luminal pressurization. The at least one design feature includes at least one of a reducing mechanism or a purse-string provided along at least part of a circumference of the body to actuate reduction of a diameter of the device. The prosthetic device may include a body with an axial length configured to be adjustable and at least one roll-down segment at one end of the body. The at least one roll-down segment may be configured to be facilitated or supported by integrated shape memory materials to maintain the roll-down characteristics.