Partially Deformable Impeller for High-Flow Catheter Blood Pumps
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Solution Overview
Problem
Catheter blood pumps face challenges in achieving a small diameter for minimally invasive insertion while maintaining high pumping capacity and avoiding hemolysis, with existing expandable impeller designs being inefficient and causing vascular trauma.
Innovation Solution
A partially deformable impeller with a partially deformable blade periphery, designed using varying materials composition, blade thickness, or structural design, allowing it to adapt to vascular constraints without full expansion, combined with a catheter blood pump having an expandable impeller housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed-diameter impeller is used, then the pump structure is simple and reliable, but the impeller diameter is limited to 9-12 Fr which prevents achieving pump flows greater than 2 liters/minute
Solution Approach 1:
The impeller is designed with dynamic deformability, allowing it to change its diameter from a smaller size during insertion to a larger size during operation. The impeller can be deformed to pass through the sheath and then expands to achieve a larger pumping diameter, resolving the contradiction between small insertion size and large pumping capacity.
Solution Approach 2:
The impeller's physical parameters (diameter, shape) are changed from a fixed state to a variable state. By controlling the deformation parameters of the impeller blades, the system transitions from a compact insertion configuration to an expanded pumping configuration, enabling both small catheter diameter and high pump flow.
2Productivity
If an expandable impeller is used to increase diameter for higher pumping capacity, then pump flow can exceed 2 liters/minute, but the design becomes complex and causes vascular trauma
Solution Approach 1:
Different portions of the impeller have different mechanical properties. The impeller is designed with varying material composition, blade thickness, or structural design in different regions, allowing selective deformation. This local quality variation enables the impeller to deform smoothly during insertion while maintaining structural integrity during pumping, reducing vascular trauma.
Solution Approach 2:
The impeller incorporates composite materials with varying properties throughout its structure. This allows the impeller to have regions that are more compliant for insertion and regions that maintain rigidity for pumping, reducing the harmful effects of expansion while achieving necessary pumping capacity.
3Productivity
If the impeller diameter is increased to improve pumping capacity, then blood flow increases, but hemolysis increases due to higher shear stress
Solution Approach 1:
The impeller dynamically adjusts its diameter based on operational needs. During insertion, it maintains a small diameter to avoid trauma. During pumping, it expands to achieve high blood flow while the dynamic deformation capability allows for optimized blade geometry that reduces shear stress and hemolysis.
Solution Approach 2:
The impeller's geometric parameters are optimized through controlled deformation. By adjusting blade angle, curvature, and other geometric parameters during the deformation process, the system achieves high pumping capacity while minimizing shear stress on blood cells, thus reducing hemolysis.
Data Source
AI summary
A partially deformable impeller has at least two blades, wherein a periphery of each blade is deformable, the periphery being an outermost 5 to 20 percent of a width of the blade. In some embodiments, a catheter blood pump incorporates the partially deformable impeller.