Catheter Pump Motor Assembly With Magnetic Coupling
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Solution Overview
Problem
Existing mechanical circulatory support devices for treating acute heart failure are either too large for percutaneous insertion or provide insufficient flow rates, and higher rotational speeds increase the risk of hemolysis and thrombosis, necessitating a pump that can be inserted minimally-invasively and provide sufficient flow rates with reduced rotational speeds.
Innovation Solution
A catheter pump system with a drive shaft and impeller, driven by a motor assembly, allowing percutaneous insertion and capable of producing high flow rates with reduced rotational speeds, featuring a securement device to maintain engagement during operation and a damper to suppress noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump size is increased to provide sufficient flow rates, then the flow rate is improved, but the device cannot be inserted percutaneously
Solution Approach 1:
The pump components including the impeller and motor are nested within a collapsible catheter assembly that can be compressed to a small profile for percutaneous insertion. The impeller assembly is positioned within the catheter body and can be collapsed along with the catheter for insertion through the femoral artery, then expanded at the target location to provide full cardiac output flow rates.
2Productivity
If rotational speed is increased to provide higher flow rates, then the flow rate is improved, but the risk of hemolysis and thrombosis increases
Solution Approach 1:
The pump design changes the operational parameters by using a larger impeller diameter operating at lower rotational speeds rather than a smaller impeller at high speeds. This parameter change maintains sufficient flow rates (4 Lpm or more at 62 mmHg head pressure) while significantly reducing the risk of hemolysis and thrombosis associated with high-speed rotation.
3Productivity
If the motor is positioned at the distal end to drive the impeller directly, then the flow rate is improved, but the device complexity and insertion difficulty increase
Solution Approach 1:
The drive system is segmented into two separate assemblies: a drive assembly containing the motor and a driven assembly containing the impeller and driven magnet. This segmentation allows the catheter assembly to be inserted percutaneously with the driven assembly, while the drive assembly can be positioned externally or at a more accessible location, reducing insertion complexity while maintaining effective impeller drive.
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 catheter pump system achieves high flow rates, minimizes invasive procedures, and reduces the risk of hemolysis and thrombosis, providing effective cardiac support with improved clinical outcomes.
Implementation Method 1
the drive magnet is magnetically coupled to the driven magnet such that, during operation of the pump, rotation of the drive magnet induces rotation of the driven magnet and the drive shaft
Implementation Method 2
a damper to suppress noise and vibration
Data Source
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AI summary
A catheter pump is disclosed herein. The catheter pump can include a catheter assembly that comprises a drive shaft and an impeller coupled to a distal end of the drive shaft. A driven assembly can be coupled to a proximal end of the drive shaft within a driven assembly housing. The catheter pump can also include a drive system that comprises a motor and a drive magnet coupled to an output shaft of the motor. The drive system can include a drive assembly housing having at least one magnet therein. Further, a securement device can be configured to prevent disengagement of the driven assembly housing from the drive assembly housing during operation of the pump.