Segmented Impeller Bladelets for Blood Pump Efficiency
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Solution Overview
Problem
Current expandable impellers for percutaneously-insertable blood pumps face challenges in achieving the necessary blade span for efficient blood pumping while maintaining structural rigidity and efficiency, particularly when operating at lower speeds and requiring a compact size for minimally-invasive insertion.
Innovation Solution
The design incorporates bladelets with a concave pressure face and convex suction face, segmented to provide one-way rigidity and efficiency, allowing for a smaller radius of curvature at the root and a larger radius at the tip, covered by a membrane to maintain fluid flow and reduce torque requirements, enabling efficient pumping with less material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the impeller is made expandable to increase blade span for efficient blood pumping, then the pumping efficiency and blade span are improved, but the device complexity and structural rigidity are worsened
Solution Approach 1:
The impeller blade is divided into multiple bladelets (typically 3-7 per blade) that are arranged radially around the hub. Each bladelet is a separate structural element that can be independently formed and assembled, allowing the blade to achieve the necessary span and surface area for efficient pumping while maintaining structural integrity through modular construction
Solution Approach 2:
The expandable impeller is nested within a delivery catheter or sheath in a compressed state for percutaneous insertion. Once positioned in the target vessel, the impeller is deployed outward from the catheter to its expanded operational configuration, transitioning from a compact insertable form to a larger pumping structure
2Ease of operation
If the impeller size is reduced for percutaneous insertion, then the ease of insertion is improved, but the blade span and pumping capacity are worsened
Solution Approach 1:
The impeller is designed with dynamic size characteristics, transitioning from a small compressed state during insertion to a large expanded state during operation. The bladelets are configured to flex and extend outward when deployed, increasing the blade span and pumping capacity while maintaining a compact profile for catheter-based delivery
3Productivity
If the blade span is increased for efficient pumping, then the pumping efficiency is improved, but the stress on the drive cable is worsened
Solution Approach 1:
The bladelets are positioned with varying radial distances from the hub, with inner bladelets closer to the hub and outer bladelets extending farther outward. This graduated arrangement optimizes the distribution of hydrodynamic forces along the blade span, reducing the peak torque and drive cable stress while maintaining efficient pumping across the entire blade area
4Ease of operation
If the impeller is made compact for minimally-invasive procedures, then the ease of insertion is improved, but the structural rigidity is worsened
Solution Approach 1:
The bladelets are constructed from composite materials or multi-layer structures that provide high structural rigidity and strength-to-weight ratio. This allows the bladelets to maintain their shape and resist deformation during both the compressed insertion phase and the expanded pumping phase, ensuring structural integrity across size transitions
Data Source
AI summary
An impeller for use in conjunction with a percutaneously-insertable blood pump or other rotatable equipment includes a blade that is segmented into a plurality of overlapping or abutting bladelets. In some embodiments, the bladelets are foldable and one side of each bladelet is concave.