Collapsible Impeller Wire Frames Balance Insertion and Pumping
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Solution Overview
Problem
Existing percutaneous blood pumps face challenges in achieving a balance between flexibility for radial compression and sufficient force for blood conveyance, with existing designs often requiring careful material selection to ensure elasticity and deformability.
Innovation Solution
A radially compressible and expandable rotor for a blood pump featuring an impeller blade with a structural frame encapsulated within the blade body, utilizing skeletal shapes like honeycomb, diamond, or dragonfly wings to provide structural support and enhance hydraulic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the impeller is made flexible to allow radial compression for insertion, then ease of insertion is improved, but the ability to exert sufficient force on blood deteriorates
Solution Approach 1:
The impeller is segmented into multiple blades that can be radially compressed individually while maintaining overall structural integrity. Each blade is divided into a flexible outer portion and a stiffer inner portion, allowing the impeller to compress for insertion while maintaining pumping capability
Solution Approach 2:
The impeller uses composite construction with materials of different stiffness properties. The outer blade portions are made more flexible than the inner portions, creating a gradient structure that allows compression while maintaining sufficient rigidity for blood conveyance when expanded
2Force
If the impeller is made rigid to exert sufficient force on blood, then force on blood is improved, but ease of radial compression for insertion deteriorates
Solution Approach 1:
The impeller structure is segmented into multiple blades with varying stiffness characteristics. The blades are arranged and dimensioned so that the collective structure provides sufficient force when expanded, while individual blade flexibility enables radial compression during insertion
Solution Approach 2:
Different portions of the impeller have different mechanical properties - the outer blade portions are made more flexible to enable compression, while the inner portions near the hub maintain higher stiffness to provide structural support and force transmission during pumping operation
3Volume of moving object
If the impeller is compressed to small diameter for vascular positioning, then device size is reduced, but structural stability deteriorates
Solution Approach 1:
The impeller transitions from a compressed dynamic state during insertion to an expanded stable state during operation. The structure is designed to be dynamically adaptable, maintaining structural stability only when in the expanded operational configuration within the ventricle
Solution Approach 2:
The impeller is nested within a delivery catheter in the compressed state for vascular insertion, then deployed outward to its functional configuration. This nested arrangement protects structural stability during transit while allowing expansion at the target site
4Volume of moving object
If the impeller blades are made thinner to reduce device diameter, then device size is reduced, but strength and resistance to deformation deteriorates
Solution Approach 1:
The blade thickness and stiffness are varied locally along the blade length. The blades are thinner at the tips to reduce overall device diameter while maintaining adequate strength, and thicker near the hub where structural support and force transmission are critical
Solution Approach 2:
The blades use composite material construction with varying properties along their length, combining materials or structures that provide sufficient strength in critical regions while allowing thinner sections in non-critical areas to minimize device diameter
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 solution allows for easier insertion through tortuous anatomy, reduces the risk of snagging, maintains functional shape during operation, and enhances hydraulic performance while minimizing blood damage, suitable for high-risk coronary interventions and cardiogenic shock scenarios.
Implementation Method 1
the material of the rotor has to be selected carefully with respect to its elasticity properties and deformability properties
Implementation Method 2
be able to exert sufficient force on the liquid or blood to be conveyed in operation
Data Source
AI summary
A radially compressible and expandable rotor for a blood pump can include a rotor comprising at least one impeller blade having a flexible blade body, wherein the at least one impeller blade includes an elastically deformable first material that is supported by a relatively stiffer second material of a structural frame encapsulated within the blade body. The relatively stiffer second material of the structural frame can be adapted to give a supporting structure to the impeller blade body, wherein when expanded, the structural frame has a predetermined expanded shape. The second material of the structural frame can have a shape with a symmetry along a. longitudinal axis defined by the rotor.