Atrial Shunt with ePTFE Coating and Tortuous Flow Path

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Solution Overview

Problem

Existing interatrial shunts face challenges such as susceptibility to pannus formation, paradoxical embolization, inefficiency in blood flow, and difficulty in long-term patency due to material and design limitations, which affect their clinical efficacy and safety.

Innovation Solution

A shunt design featuring an hourglass or diabolo shape with a biocompatible material encapsulation that limits tissue ingrowth and a conduit configuration to reduce paradoxical embolism, enhance patency, and improve blood flow efficiency, allowing for secure implantation and reduced risk of complications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If existing interatrial shunts are used to reduce left atrial pressure, then pulmonary congestion is alleviated, but the shunts are susceptible to pannus formation and tissue ingrowth that obstructs the flow path

Engineering Contradiction:

Improvepulmonary congestionVSAvoidpannus formation and tissue ingrowth

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The shunt device is enveloped in a thin film of expanded polytetrafluoroethylene (ePTFE) that acts as a barrier to tissue ingrowth while allowing blood flow. This flexible membrane prevents pannus formation from obstructing the flow path while maintaining the shunt's functionality for reducing left atrial pressure and alleviating pulmonary congestion.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The shunt device combines different materials with complementary properties: a self-expanding metallic frame (nitinol or stainless steel) provides structural support and radial force, while the ePTFE coating provides tissue ingrowth resistance. This composite structure resolves the contradiction by integrating the load-bearing function with the anti-pannus function in a single device.

Inventive Principle:

Principle #40Composite materials

2Stress or pressure

If existing interatrial shunts are used to redirect blood flow, then left atrial pressure is reduced, but paradoxical embolization risk increases due to direct communication between atria

Engineering Contradiction:

Improveleft atrial pressureVSAvoidparadoxical embolization

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The shunt device introduces a spatial dimension to the blood flow path by creating a tortuous, multi-directional flow channel rather than a direct linear path. The self-expanding frame with its circumferential and longitudinal struts creates a three-dimensional structure that forces blood to follow a complex trajectory, increasing the path length and reducing the risk of direct embolus transmission while maintaining pressure reduction effectiveness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The shunt device employs curved and angled struts that create a non-linear, serpentine flow path. The circumferential struts are configured with sinusoidal or serpentine bends, and the longitudinal struts create angled transitions, forcing blood flow to follow curved trajectories rather than straight lines. This curvature increases the physical distance emboli must travel and reduces the efficiency of paradoxical embolization while preserving the hemodynamic benefit of left atrial decompression.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Reliability

If existing interatrial shunts are used to treat heart failure, then cardiac function is improved, but long-term patency is compromised due to material limitations and design flaws

Engineering Contradiction:

Improvecardiac function improvementVSAvoidlong-term patency

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The shunt device utilizes the temperature-dependent shape memory properties of nitinol or the elastic recovery properties of stainless steel to transition from a compressed delivery state to an expanded functional state. This parameter change enables the device to self-expand to its predetermined geometric configuration upon deployment, ensuring proper engagement with the atrial septum and optimal flow characteristics that maintain long-term patency and reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The shunt device incorporates dynamic elements including self-expanding struts that actively engage with the atrial septum to maintain patency, and a flexible ePTFE coating that can accommodate tissue remodeling over time. The device transitions from a passive implant to an active structure that maintains its functional geometry through self-expansion forces and flexible adaptation, ensuring long-term patency and reliable heart failure treatment.

Inventive Principle:

Principle #15Dynamics

4Stress or pressure

If existing interatrial shunts are used to redistribute blood volume, then pulmonary artery pressure is lowered, but the shunts experience flow inefficiency due to suboptimal geometry

Engineering Contradiction:

Improvepulmonary artery pressureVSAvoidblood flow efficiency

Core Design Contradiction:

Stress or pressureVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10925706B2Shunt for redistributing atrial blood volume

Publication Date: 2021.02.23 WAVE LTD V

AI summary

A shunt for regulating blood pressure between a patient's left atrium and right atrium comprises an anchor comprising a neck region, first and second end regions, and a conduit affixed with the anchor that formed of a biocompatible material that is resistant to transmural and translation tissue ingrowth and that reduces a risk of paradoxical embolism.