Expandable Cannula Blood Pump with Foldable Impeller Blades

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Solution Overview

Problem

Existing blood pumps face challenges such as blood leakage through guide wire lumens, maintaining the impeller's centering within the cannula, and optimizing the shape of the expandable cannula for performance, particularly during percutaneous insertion and operation within the vascular system.

Innovation Solution

The design incorporates a hub with a passageway and a valve that can occlude flow in both directions, a blade assembly that compresses for insertion and expands for operation, and an expandable cannula with a polymer coating and reinforcing matrix, along with a vane assembly that moves longitudinally with the impeller but does not rotate, to enhance blood flow and maintain centering within the cannula.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cannula is made with a small fixed diameter for percutaneous insertion, then ease of insertion is improved, but blood flow capacity deteriorates

Engineering Contradiction:

Improveease of insertionVSAvoidblood flow capacity

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The cannula transitions from a static fixed diameter to a dynamic variable diameter structure. The expandable portion can change its cross-sectional area from a compressed state during insertion to an expanded state during operation, allowing the same structure to satisfy both small insertion profile and large blood flow capacity requirements at different operational phases

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The expandable cannula structure allows the larger diameter cannula to be nested within a delivery sheath during insertion, similar to nested dolls. The compressed expandable portion fits within the sheath for percutaneous access, then expands outward after deployment to provide adequate blood flow capacity

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If the cannula is made expandable to increase blood flow capacity, then productivity is improved, but device complexity worsens

Engineering Contradiction:

Improveblood flow capacityVSAvoidcannula structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The expandable portion is constructed using flexible materials including a mesh structure and elastomeric coating that can naturally expand and contract. This flexible shell approach simplifies the structure compared to rigid mechanical expansion mechanisms, reducing overall device complexity while achieving the required blood flow capacity

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The cannula employs composite material construction with a mesh framework and elastomeric coating layers. This composite structure provides both the mechanical strength needed for structural integrity and the flexibility required for expansion, achieving high blood flow capacity without overly complex single-material solutions

Inventive Principle:

Principle #40Composite materials

3Productivity

If the impeller blades are extended for effective pumping, then productivity is improved, but ease of insertion deteriorates

Engineering Contradiction:

Improvepumping effectivenessVSAvoidease of insertion

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The impeller blades are designed as dynamic components that can change their radial extent. During insertion, the blades are in a compressed retracted configuration reducing the overall diameter for percutaneous access. After deployment, the blades extend to their full operational length to provide effective pumping action

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The impeller is pre-compressed into a compact configuration before insertion to facilitate ease of passage through the vascular system. Once deployed in the target location, the impeller is then expanded to its operational configuration with blades extended for effective blood pumping

Inventive Principle:

Principle #10Preliminary action

4Stability of the object's composition

If the cannula is made rigid for structural stability, then stability is improved, but ease of insertion deteriorates

Engineering Contradiction:

Improvestructural stabilityVSAvoidease of insertion

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The cannula employs local quality differentiation with a fixed diameter portion that provides structural stability and rigidity where needed, while the expandable portion provides flexibility and compressibility for insertion. This localized variation in mechanical properties allows the structure to be rigid when required and flexible when required

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP2448613B1Blood pump with expandable cannula

Publication Date: 2019.11.06 TC1 LLC

Figure 1
Figure 2A~2C
Figure 3

AI summary

A blood pump (10) includes an impeller having a plurality of foldable blades and a cannula (40) having a proximal portion with a fixed diameter, and a distal portion with an expandable diameter. The impeller can reside in the expandable portion of the cannula. The cannula has a collapsed condition for percutaneous delivery to a desired location within the body, and an expanded condition in which the impeller can rotate to pump blood. A flexible drive shaft can extend through the cannula for rotationally driving the impeller within the patient's body.