Nitinol-Reinforced Cannula Inflow Apertures for Low-Trauma Insertion

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Solution Overview

Problem

Heart pump assemblies with stainless-steel inflow apertures can cause hemolysis and damage due to sharp edges, and are prone to damage during insertion due to their rigidity.

Innovation Solution

Inflow apertures reinforced with a shape memory material, such as nitinol, embedded in a polymer cannula, with edges coated to prevent blood damage and increase flexibility, allowing the cannula to withstand insertion forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If stainless-steel inflow apertures are used, then structural strength is improved, but hemolysis and tissue damage occur due to sharp edges

Engineering Contradiction:

Improvestructural strengthVSAvoidhemolysis and tissue damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies this principle by using a shape memory alloy (SMA) sheet with a thickness of 0.002 to 0.006 inches, which is significantly thinner than traditional stainless-steel structures. The SMA sheet forms the inflow aperture structure with inherently smooth edges that do not contact blood, eliminating hemolysis while maintaining structural integrity through the memory metal properties

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent applies this principle by creating a composite structure consisting of a shape memory alloy sheet embedded within a polymer cannula body. This composite design combines the strength and shape retention properties of the SMA with the biocompatibility and flexibility of the polymer, achieving both structural strength and hemolysis prevention

Inventive Principle:

Principle #40Composite materials

2Strength

If stainless-steel inflow apertures are used, then structural strength is improved, but damage during insertion occurs due to rigidity

Engineering Contradiction:

Improvestructural strengthVSAvoiddamage during insertion

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent applies this principle by utilizing the shape memory alloy's ability to dynamically change its mechanical properties. The SMA sheet can be deformed during insertion to navigate the delivery system, then returns to its original shape at the implantation site, providing both flexibility during insertion and structural strength during operation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies this principle by changing the temperature parameter to activate the shape memory effect. The SMA sheet is cooled during insertion to become flexible, then warmed at the implantation site to regain its structural strength and predefined shape, resolving the contradiction between rigidity and flexibility

Inventive Principle:

Principle #35Parameter changes

3Strength

If traditional materials are used, then structural integrity is maintained, but miniaturization is limited

Engineering Contradiction:

Improvestructural integrityVSAvoidpump size

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

The patent applies this principle by using an ultra-thin SMA sheet (0.002 to 0.006 inches) that provides sufficient structural integrity for the inflow aperture while minimizing the overall pump size. The memory metal properties compensate for the reduced thickness, allowing miniaturization without sacrificing strength

Inventive Principle:

Principle #30Flexible shells and thin films

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 reinforced inflow apertures reduce damage to blood and tissues, enable miniaturization of the heart pump, and allow safe positioning across the aortic valve without tissue damage.

Implementation Method 1

The reinforced inflow aperture portion can withstand the stress of squeezing or bending and return to an original shape after exposure to such stress

Methodology Applied

Scientific EffectShape memory effect: Shape Memory Alloy

Implementation Method 2

Nitinol can be manufactured to be thinner than other commonly used biocompatible materials such as stainless steel, and is more flexible for easier use and handling

Methodology Applied

Scientific EffectSuperelasticity: Pseudoelasticity

Data Source

PatentUS20260000859A1Cannula having nitinol reinforced inflow region

Publication Date: 2026.01.01 ABIOMED INC

AI summary

An intravascular heart pump assembly can include a rotor with at least one impeller blade, and a cannula. The present application describes various cannulas that can be manufactured from multiple layers of material to improve flexibility, manufacturability, and durability without increasing an outer diameter of the cannula. In one embodiment, the cannula includes an inflow section having a sheet formed of a shape memory material embedded within a polymer and having at least one lateral hole or aperture in the inflow section. The at least one lateral hole is defined by a first hole in the sheet and a second hole in the outer polymer layer of the cannula. The first hole and the second hole overlap so that blood can enter the cannula through the holes.