Expandable Cardiac Pump Radial Deployment
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Solution Overview
Problem
Current percutaneously-inserted blood pumps for cardiac assistance face challenges such as limited pump flow, hemolysis, the need for large catheters risking ischemia, and high costs, due to their small size and complex deployment mechanisms which often result in axial forces leading to wear and leakage issues.
Innovation Solution
A percutaneously-inserted, expandable cardiac-assist device with a pump assembly that deploys in the ascending aorta, featuring a torque transmission line driving impeller blades, and a reconfigurable casing that expands without axial forces, reducing stress on the drive cable and eliminating the need for axial loads, thus enhancing flow and minimizing hemolysis and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the blood pump is made small for percutaneous insertion, then the invasiveness is reduced, but the pump flow is limited
Solution Approach 1:
The pump assembly transitions from a compressed delivery state to an expanded operational state. The casing expands radially outward to increase the impeller diameter and pump flow capacity, while the impeller blades transition from a collapsed configuration to a deployed configuration that spans a larger diameter, enabling high flow rates through a small access catheter.
Solution Approach 2:
The pump assembly is nested within a delivery catheter in a compressed state for percutaneous insertion. The casing and impeller blades are contained within the catheter lumen, allowing the entire pump system to be delivered through a small-bore catheter. Upon deployment, the pump assembly expands outward from the catheter to its operational dimensions.
2Productivity
If an expandable pump is deployed to increase flow, then the pump flow is improved, but axial forces cause wear and leakage
Solution Approach 1:
Instead of applying axial force to expand the pump, the invention uses radial expansion force. The casing expands radially outward from the delivery catheter, and the impeller blades deploy radially outward to their operational diameter. This inversion of the expansion mechanism eliminates axial compression forces on the drive cable, reducing wear and leakage at the drive cable seal interface.
Solution Approach 2:
The invention extracts the drive cable from the blood-contacting environment by routing it through a sealed drive shaft that extends through the pump assembly. The drive cable seal is positioned outside the pump housing, isolating it from blood contact and reducing hemolysis and thrombosis risks while maintaining reliable torque transmission to the impeller.
3Productivity
If a large catheter is used to deliver the pump, then the pump flow capability is improved, but the risk of ischemia increases
Solution Approach 1:
The pump assembly dynamically changes from a compact delivered state to an expanded operational state. The casing and impeller blades expand radially outward after delivery through the small catheter, achieving a large operational diameter (impeller blades spanning greater than catheter diameter) that enables high pump flow rates without requiring a large delivery catheter.
Solution Approach 2:
The pump assembly utilizes radial expansion to increase pump flow capacity. By expanding in the radial dimension after delivery, the pump achieves a large operational footprint without requiring a large delivery catheter. The impeller blades deploy radially outward to span a diameter greater than the delivery catheter, enabling high flow rates through a small access point.
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 solution achieves increased pump flow rates and reduced hemolysis and wear, simplifying deployment and operation while maintaining stability and reducing the risk of ischemia and leakage, thereby improving the efficacy of cardiac assistance.
Implementation Method 1
A torque transmission line couples the pump assembly to an extracorporeal motor.
Implementation Method 2
an expandable, reconfigurable casing
Data Source
AI summary
A temporary cardiac-assist device is disclosed. The device includes a pump assembly that is deployed in the ascending aorta or the heart. A torque transmission line couples the pump assembly to an external motor for driving impeller blades within the pump assembly. The pump assembly expands in size at its destination site for operation. In operation, neither the torque transmission line nor elements that support the impeller blades are under axial forces.