Expandable Impeller Geometry for Percutaneous Heart Pump Flow
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Solution Overview
Problem
There is a need for improved mechanical circulatory support devices that can provide full cardiac flow rates minimally-invasively, with reduced risk of hemolysis and thrombosis, and capable of percutaneous insertion through small incisions.
Innovation Solution
A percutaneous heart pump system featuring an expandable and collapsible impeller with a hub and blades that self-expand to increase flow rate while maintaining a small diameter for insertion, operated at reduced rotational speeds to minimize hemolysis risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the impeller is designed with a large diameter to provide high flow rates, then the flow rate is improved, but the device cannot be inserted percutaneously through small incisions
Solution Approach 1:
The impeller is designed with flexible blades that can dynamically change their configuration between a compressed state for insertion and an expanded state for operation. The blades are made of flexible material allowing them to bend and adapt their shape, enabling the impeller to pass through small percutaneous access sites and then expand to provide high flow rates during heart pump operation
Solution Approach 2:
The impeller is designed to nest within itself or within the delivery catheter during the insertion phase. The flexible blades can be compressed against each other or against the catheter wall, allowing the entire impeller assembly to fit within a small-profile delivery system that can be inserted through percutaneous access sites, and then deploy to full size upon reaching the target location
2Productivity
If the rotational speed is increased to provide higher flow rates, then the productivity is improved, but the risk of hemolysis increases
Solution Approach 1:
The patent changes the geometric parameters of the impeller, specifically the blade shape, curvature, and arrangement, to optimize the flow characteristics. By modifying these parameters, the impeller can generate higher flow rates at lower rotational speeds, reducing the shear forces that cause hemolysis while maintaining the required productivity for heart pump operation
3Productivity
If the impeller is designed to provide full heart flow rates, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The impeller blades are constructed from flexible material that allows them to bend and deform as needed. This flexibility eliminates the need for complex mechanical joints, bearings, or segmentation that would be required for a rigid impeller of similar performance. The flexible blade structure achieves the required flow rates through elastic deformation and streamlined geometry, simplifying the overall device design while maintaining high productivity
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 system achieves high blood flow rates of up to 10 Lpm at 62 mmHg with reduced rotational speeds, minimizing damage to blood cells and enabling safe percutaneous insertion through small incisions.
Implementation Method 1
The blade can include a curved surface having a radius of curvature. The radius of curvature can be larger in the operational configuration than when the impeller is in the deployed configuration.
Implementation Method 2
The impeller can have a stored configuration when the impeller is at rest, a deployed configuration when the impeller is at rest, and an operational configuration when the impeller rotates.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A mechanical circulatory support device for stabilizing a patient after cardiogenic shock comprises a heart pump, including a catheter body and an impeller operative to increase blood flow and stabilize the patient when the impeller is rotated at a predetermined speed. The impeller includes a hub having a circumference and a plurality of blades, each of the plurality of blades respectively having a fixed end joined to the circumference of the hub. The plurality of blades are transitionable between a stored position folded against the hub and a deployed position extending radially outwardly from the hub. The stored position is dimensioned for an insertion of the impeller through a portion of a vascular system of the patient to a heart chamber. Each of the fixed ends of the plurality of blades respectively extends helically around the circumference of the hub to complete a wrapping angle between about 150 degrees and about 220 degrees.