FFR Catheter Sensor Suspension via Flexible PCB

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Solution Overview

Problem

Conventional FFR devices experience inaccurate pressure measurements due to torsional forces affecting the pressure sensor, leading to errors in Fractional Flow Reserve calculations, and manufacturing challenges arise from the complex assembly of sensors within the distal shaft portion of catheters or guidewires.

Innovation Solution

A catheter or guidewire system with a distal shaft housing a pressure sensor suspended on a flexible printed circuit board, isolated from external stresses through a sensor lumen and fixation points, allowing blood flow through an aperture for accurate pressure measurement, and a method for manufacturing this system that simplifies the assembly by using a separate cover and fixation points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the pressure sensor is mounted directly on the distal shaft portion, then the manufacturing process becomes simpler, but the sensor becomes vulnerable to torsional forces causing inaccurate measurements

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpressure measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces a flexible printed circuit board (PCB) as an intermediary element between the distal shaft portion and the pressure sensor. The PCB is coupled to the distal shaft portion and suspends the pressure sensor thereon, creating a mechanical decoupling that protects the sensor from torsional forces while maintaining the manufacturing simplicity of direct mounting. This intermediary structure allows the sensor to be isolated from harmful stresses without complicating the overall assembly process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the pressure sensor is suspended on a flexible printed circuit board, then the sensor is protected from torsional forces, but the manufacturing complexity increases

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidstructural complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a flexible printed circuit board (PCB) as a thin, flexible structure that serves multiple functions: it provides mechanical support for the pressure sensor, electrical connections, and acts as a protective element isolating the sensor from torsional forces. The flexible nature of the PCB allows it to conform to the distal shaft portion while maintaining the sensor's protection, achieving a balance between structural complexity and functional requirements.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If the distal shaft portion is designed with a housing and cover structure, then the sensor is better protected from external stresses, but the manufacturing process becomes more difficult

Engineering Contradiction:
Improvesensor stabilityVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the protective structure into separate components: a distal shaft portion housing and a removable cover. The pressure sensor is mounted on the flexible PCB within the housing, and the cover can be separately attached to complete the protective enclosure. This segmentation allows each component to be manufactured and assembled independently, reducing the overall manufacturing difficulty while maintaining the reliability benefits of a complete housing structure.

Inventive Principle:
Principle #1Segmentation

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 provides stable and accurate distal pressure measurements, reducing errors from torsional forces and simplifying the manufacturing process, enabling precise Fractional Flow Reserve calculations.

Implementation Method 1

A flexible printed circuit board is coupled to the housing. The pressure sensor is coupled to the flexible printed circuit board and suspended within the housing

Methodology Applied
Scientific EffectMechanical Isolation:

Implementation Method 2

An aperture is configured to allow blood flow into the housing and into contact with the pressure sensor

Methodology Applied
Scientific EffectFluid Flow:

Data Source

PatentEP3836833B1FFR catheter with suspended pressure sensor and method of manufacture
Publication Date: 2024.03.27 MEDTRONIC VASCULAR INC
  • EP3836833B1 patent drawingFigure 1
  • EP3836833B1 patent drawingFigure 2
  • EP3836833B1 patent drawingFigure 3

AI summary

A catheter for measuring a pressure distal of a stenosis includes a shaft including a housing in a distal portion of the shaft. A flexible printed circuit board is coupled to the housing. A pressure sensor is coupled to the flexible printed circuit board and is suspended within the housing. An aperture enables blood flow into the housing and into contact with the pressure sensor.