Expandable Impeller Housing for Percutaneous Heart Pump
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Solution Overview
Problem
Conventional heart pumps with fixed cross-sections are too large for percutaneous insertion, limiting their ability to provide full cardiac flow rates for left, right, or both sides of the heart, necessitating a more compact and expandable design for effective mechanical circulatory support.
Innovation Solution
A catheter assembly with an elongate tubular member and impeller assembly featuring a fixed profile proximal portion, an expandable portion, and struts that move from a low to a higher profile configuration, along with a stiffening member to limit deflection, allowing percutaneous insertion and expansion within the heart for enhanced flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional fixed cross-section heart pump is used, then it can provide full cardiac flow rates, but it is too large for percutaneous insertion
Solution Approach 1:
The pump housing transitions from a fixed cross-section design to a dynamic expandable design, allowing the pump to change its volume and shape during operation. The housing can be compressed to a low profile for percutaneous insertion and then expanded to a larger profile to provide full cardiac flow rates, resolving the contradiction between small insertion size and large operational size
Solution Approach 2:
The pump housing is designed with nested structural elements that allow compression during insertion. The expandable portion can be collapsed within the catheter assembly during percutaneous insertion, similar to nested dolls, and then deployed to its full operational size once positioned in the heart chamber
2Ease of operation
If the impeller housing is made expandable for percutaneous insertion, then insertability is improved, but structural stability and flow rate capability may be compromised
Solution Approach 1:
The impeller housing is divided into distinct segments: a fixed profile proximal portion that provides structural stability and anchoring, and an expandable distal portion that enables percutaneous insertion. This segmentation allows each portion to fulfill its specific function without compromising the other
Solution Approach 2:
Different portions of the housing have different structural properties tailored to their specific functions. The proximal portion maintains a fixed, rigid structure for stability and anchoring in the heart chamber, while the distal portion is designed to be expandable and flexible for insertion, creating local quality variations that resolve the stability-insertability contradiction
3Adaptability or versatility
If struts are made flexible to allow expansion, then expandability is improved, but deflection control becomes difficult
Solution Approach 1:
The struts are designed with controlled flexibility parameters that allow them to bend and enable expansion during insertion, but maintain sufficient stiffness to limit deflection during pump operation. The material properties and geometric parameters of the struts are optimized to provide the right balance between expandability and deflection control
Data Source
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AI summary
Disclosed herein are heart pumps that include a catheter assembly and that can be applied percutaneously. Some embodiments include a locking device that prevents components of the catheter assembly from being separated when in use. The catheter assembly can include an expandable tip. In some embodiments, the catheter assembly includes a housing having a wall structure, a portion of which can have a bulbuous shape or can be deformable. In other embodiments, the housing can be configured to reduce fluttering or deflection of the housing and/or to maintain a gap between the housing and an impeller blade disposed therein.