Collapsible Catheter Pump Impeller for High Flow at Lower RPM
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Solution Overview
Problem
There is a need for improved mechanical circulatory support devices that can be inserted minimally-invasively to provide full cardiac flow rates with reduced risk of hemolysis and thrombosis, while maintaining high flow rates and reducing rotational speeds.
Innovation Solution
The development of an impeller for a catheter pump with a hub and blades that can be compressed into a stored configuration for percutaneous insertion, expanding to a deployed configuration for operation, and configured to pump blood at high flow rates with reduced rotational speeds, minimizing damage to blood cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flow rate of a rotary pump is increased by rotating the impeller faster, then the flow rate is improved, but the risk of hemolysis increases
Solution Approach 1:
The patent changes the geometric parameters of the impeller blades, specifically the blade width, blade curvature radius, and blade angle, to optimize the flow characteristics. This allows achieving higher flow rates without proportionally increasing rotational speed, thereby reducing hemolysis risk while maintaining productivity
Solution Approach 2:
The impeller blades are designed with curved surfaces and varying cross-sections along the blade length, creating dynamic flow patterns that reduce turbulence and shear stress on blood cells during rotation, thus lowering hemolysis risk at operational speeds
2Productivity
If a fixed cross-section ventricular assist device is designed to provide near full heart flow rate, then the flow rate is improved, but the device size becomes too large to be advanced percutaneously
Solution Approach 1:
The pump system is divided into separate components: a collapsible impeller assembly that can be compressed into a compact form for percutaneous delivery, and a stationary housing remaining in the body. The impeller can be advanced through a catheter and then expanded to its operational configuration inside the heart
Solution Approach 2:
The impeller assembly is designed to be nested within a delivery catheter or sheath during insertion. The impeller can be compressed into a stored configuration that fits within the catheter lumen, then deployed to its full operational size once positioned in the heart chamber
3Productivity
If the impeller is designed to provide sufficient flow rates, then the flow rate is improved, but the rotational speed must be increased, which increases hemolysis risk
Solution Approach 1:
The patent optimizes the blade geometry parameters including blade width, curvature radius, and angle to maximize flow generation efficiency. This allows the impeller to achieve sufficient flow rates at lower rotational speeds, reducing the harmful effects of high-speed rotation on blood cells
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 impeller achieves high flow rates of up to 10 Lpm at 62 mmHg with reduced rotational speeds, minimizing hemolysis and thrombosis risk, and can be inserted through a 15FR or 12FR incision, providing effective circulatory support for heart failure.
Implementation Method 1
The impeller can include a hub and one or more blades. Each blade can have a curved surface with a radius of curvature that varies along the length of the blade.
Implementation Method 2
The impeller can have a stored configuration and a deployed configuration. The impeller can be collapsible such that the impeller can be compressed from the deployed configuration to the stored configuration.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
An impeller for a catheter pump comprises a hub, having a proximal end portion and a distal end portion, and at least one blade supported by the hub, transitionable between a stored position and a deployed position and having a fixed end coupled to the hub and a free end. The at least one blade comprises a distal blade angle, a proximal blade angle and a middle blade angle. The distal blade angle is larger than the middle blade angle and the middle blade angle is larger than the proximal blade angle.