Flexible Cannula Circulatory Support Device with Expandable Cages
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Solution Overview
Problem
Traditional circulatory support devices cause stress on heart valves and are prone to movement, leading to pressure differences and the need for repositioning, especially in cases of motor failure.
Innovation Solution
A flexible cannula-based circulatory support device with a pump assembly, expandable cages, and a helical tube, designed to be compressible through aortic valve openings, along with a mesh skirt to facilitate blood flow and prevent mechanical damage, allowing the aortic valve to close without leakage and maintaining device position during patient movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid circulatory support device is used, then the device can maintain structural integrity and pump function, but the device causes stress on the aortic valve when the valve closes over it and is prone to moving requiring repositioning
Solution Approach 1:
The device employs a flexible cannula made of compliant material that can be compressed by the aortic valve during closure. This flexible structure allows the valve to close naturally over the device without generating excessive stress, while the cannula maintains sufficient structural integrity to support the pump assembly and conduct blood flow.
Solution Approach 2:
The device incorporates expandable cages at both ends that can transition between compressed and expanded states. When the aortic valve closes, the distal end compresses flexibly; when the valve opens, the cage expands to secure the device position. This dynamic behavior allows the device to adapt to valve motion, preventing displacement and eliminating the need for repositioning.
2Productivity
If the device size is increased to improve pump capacity, then blood flow capability is enhanced, but the device causes more stress on the valve and creates pressure differences between left ventricle and aorta
Solution Approach 1:
The device divides the cannula into multiple segments with expandable cages at each end. This segmentation allows the device to achieve sufficient pump capacity through the impeller while distributing mechanical stress across multiple flexible joints rather than concentrating it at a single rigid structure, reducing overall valve stress and pressure differences.
Solution Approach 2:
The device uses parameter changes in the form of expandable/collapsible cages that alter the device's effective size and compliance. During valve closure, the cages compress to reduce stress; during normal operation, they expand to maintain pump capacity and secure positioning, thereby achieving high productivity without excessive valve stress or pressure differences.
3Stress or pressure
If the device uses a flexible cannula to reduce valve stress, then valve compatibility is improved, but the device may be less stable and require securement mechanisms
Solution Approach 1:
The device employs expandable cages at both ends that dynamically transition between compressed and expanded states. During valve closure, the flexible cannula compresses to reduce stress; during normal operation, the cages expand to engage with the ventricle and aorta, providing stable anchoring that prevents device migration without requiring additional securement mechanisms.
4Stress or pressure
If the device is designed to be compressible through the aortic valve, then valve compatibility is improved, but the device requires expandable structures that increase complexity
Solution Approach 1:
The device uses a flexible cannula with integrated expandable cages made from compliant materials that can be compressed through the aortic valve in a collapsed state. The cages expand after deployment to provide stability, achieving valve compatibility without requiring complex deployment mechanisms or multiple separate components.
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 device reduces stress on heart valves, minimizes pressure differences, and secures its position within the vasculature, ensuring continuous blood flow and reducing the need for repositioning, even during motor failure.
Implementation Method 1
an impeller, driven to rotate by the motor, and configured to push blood toward the fluid outlet
Implementation Method 2
at least a portion of the flexible cannula is configured to be disposed through an aortic valve opening and is configured to be compressible such that the aortic valve can close on the at least the portion of the flexible cannula
Implementation Method 3
an expandable cage coupled to the distal end of the pump housing
Data Source
AI summary
A circulatory support device includes a flexible cannula having a fluid outlet at a proximal end; and a pump assembly disposed at a distal end of the flexible cannula. The pump assembly includes a pump housing having a fluid inlet defined therein; a motor disposed within a distal end of the housing; and an impeller, driven to rotate by the motor, and configured to push blood toward the fluid outlet.