Catheter Pump Collapsible Mesh Cannula Fracture Prevention
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Solution Overview
Problem
There is a need for a percutaneously insertable catheter pump that can provide full cardiac rate flows for the left, right, or both sides of the heart, while also requiring a cannula that can expand and collapse reliably without risking breakage, especially during re-sheathing.
Innovation Solution
The catheter pump includes a rotatable impeller and an elongate cannula with a mesh structure composed of circumferential members and connectors. The cannula is designed to be differentiated along its length for varying stiffness, with the impeller zone having alternating struts connected by circumferential connectors and the distal zone having struts without such connections, minimizing the risk of fracture during collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cannula is made with a fixed cross-section to provide sufficient expansion force and stable shape, then the structural strength is improved, but the device cannot be collapsed for percutaneous insertion
Solution Approach 1:
The cannula transitions from a fixed cross-section to a dynamic structure with expandable and collapsible mesh. The mesh comprises circumferential members connected by connectors that allow the cannula to change its cross-sectional area dynamically - expanded during operation for structural strength, collapsed during insertion for percutaneous delivery.
Solution Approach 2:
The collapsible mesh cannula can be nested within a delivery sheath for percutaneous insertion. After deployment, the mesh expands from the sheath to provide the required structural strength and stable shape for pump operation, then can be recollapsed and re-nested for retrieval.
2Ease of operation
If the cannula is made collapsible to allow percutaneous insertion, then the ease of insertion is improved, but the risk of breakage during re-sheathing increases
Solution Approach 1:
The stiffness parameter of the cannula is changed along its length through differentiated connector placement. The proximal region has higher connector density for stiffness during collapse, while the distal region has lower connector density for flexibility during expansion and operation, reducing stress concentration and breakage risk.
Solution Approach 2:
The mesh structure is designed with inherent flexibility and energy-absorbing characteristics that cushion the stresses encountered during re-sheathing. The gradual transition zones and distributed connector placement prevent stress concentration that could lead to sudden failure.
3Stability of the object's composition
If the cannula has uniform stiffness throughout to maintain stable shape, then the structural stability is improved, but the ability to collapse reliably is worsened
Solution Approach 1:
The cannula is designed with non-uniform connector distribution along its length. The proximal region has higher connector density providing greater stiffness for stable shape maintenance during operation, while the distal region has lower connector density allowing easier collapse and flexibility during insertion and retrieval.
4Productivity
If conventional fixed cross-section pumps are used to provide full cardiac rate flows, then the flow rate capability is improved, but the device size becomes too large for percutaneous insertion
Solution Approach 1:
The pump incorporates a dynamically expandable mesh structure that transitions from a compact collapsed state for percutaneous insertion to an expanded operational state that provides full cardiac rate flow capability. The mesh expansion increases the effective pump volume and flow cross-section during operation.
Solution Approach 2:
The pump components including the impeller and mesh structure are designed to nest within a delivery catheter for percutaneous insertion. Once deployed, the mesh expands from the catheter to provide the required pump volume and flow capability, effectively transitioning from a small insertable form to a large operational form.
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 enables the catheter pump to achieve high flow rates comparable to full cardiac output while ensuring reliable expansion and collapse of the cannula, reducing the risk of breakage and complications during patient treatment.
Implementation Method 1
The apparatus can include a rotatable impeller and an elongate cannula
Data Source
AI summary
A catheter pump includes an elongate cannula with a formed mesh structure extending cylindrically between opposing ends thereof. The formed mesh structure defines a pattern configured to be stably expandable and collapsible without fracturing in a percutaneous delivery and re-sheathing in the provision of mechanical circulatory support of a patient's heart.