Expandable Cardiac Assist Pump for High Flow, Low-Trauma Delivery
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Solution Overview
Problem
Current circulatory assist devices, such as IABP, ECMO systems, and impeller pumps, fail to provide adequate blood flow support for patients with cardiogenic shock or high-risk PCI, often requiring surgical placement, causing hemolysis, trauma, and other complications.
Innovation Solution
A percutaneously deliverable cardiac assist device with a compact profile and expandable cup mechanism, utilizing a volume displacement member to cyclically pump blood at high frequencies, creating a Venturi effect for enhanced flow rates up to 10 L/min with reduced hemolysis and trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If impeller pumps are made larger to produce higher flows, then blood flow rate increases, but device profile becomes too large for percutaneous delivery and causes trauma to cardiovascular structures
Solution Approach 1:
The pump chamber is designed to dynamically expand and contract during operation. In the delivery state, the pump chamber is compressed to a small profile for percutaneous insertion. Upon deployment, the pump chamber expands to a larger operational size, allowing high flow rates without requiring a large delivery profile. This dynamic transformation resolves the contradiction between needing large pump size for high flow and small profile for delivery.
Solution Approach 2:
The pump chamber is nested within a delivery catheter in a compressed state for insertion. After deployment, the pump chamber expands outward from the catheter structure. This nesting approach allows the large operational pump to be delivered through a small catheter, resolving the size contradiction.
2Productivity
If impeller pumps are operated at higher speeds to produce higher flows, then blood flow rate increases, but hemolysis increases
Solution Approach 1:
The invention replaces the traditional rotary impeller mechanical system with a volumetric displacement system using a expandable pump chamber and diaphragm. This new mechanical system moves blood through controlled volume changes rather than high-speed rotation, achieving high flow rates without the excessive shear forces that cause hemolysis in impeller pumps.
Solution Approach 2:
The pump operates through periodic expansion and contraction cycles of the pump chamber. This periodic volumetric displacement creates smooth, pulsatile blood flow that avoids the turbulent high-speed rotation of impeller pumps, thereby reducing hemolysis while maintaining high flow rates.
3Productivity
If circulatory assist devices are designed to produce high blood flows for cardiogenic shock, then blood flow rate increases, but device complexity and surgical placement requirements increase
Solution Approach 1:
The device is segmented into modular components: a delivery catheter, an expandable pump chamber, a diaphragm actuator, and a drive mechanism. This segmentation allows the complex high-flow pump to be delivered through a simple catheter structure and deployed at the target site, reducing overall placement complexity while maintaining high flow capability.
Solution Approach 2:
The pump chamber transitions from a one-dimensional compressed state during delivery to a three-dimensional expanded state during operation. This dimensional transformation allows the device to achieve high flow rates (requiring large pump volume) without requiring a large delivery profile, simplifying the placement process while maintaining productivity.
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 device achieves high blood flow rates suitable for cardiogenic shock and PCI, with minimal trauma and hemolysis, enabling efficient hemodynamic support through a small, endovascularly deliverable design.
Implementation Method 1
a volume displacement member positioned inside the pumping chamber and cyclically movable between a low-volume state and a high-volume state
Implementation Method 2
creating a Venturi effect for enhanced flow rates up to 10 L/min
Data Source
AI summary
A cardiac assist device includes an expandable cup with a pumping chamber having at least one inflow aperture, an outflow nozzle in communication with the chamber, and a volume displacement member inside the chamber. The volume displacement member is cyclically movable between a low-volume state and a high-volume state at a frequency F, wherein a displacement volume of blood Vd is displaced from the chamber through the nozzle during each cycle. When the volume displacement member moves at frequency F, the device increases momentum of blood flowing through the device such that flow rate of blood exiting the nozzle is substantially greater than the frequency F multiplied by the displacement volume Vd. In some embodiments, the volume displacement member includes a balloon having a proximal region that is distanced from an inner wall of the chamber more than a distal region of the balloon when the balloon is fully inflated.