FFR Sensor Head Design Minimizes Stress-Induced Pressure Offsets
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Solution Overview
Problem
Existing medical devices face challenges in maintaining accurate blood pressure measurements during navigation through vasculature due to steering, tracking, or torquing, which can result in undesirable pressure shifts or offsets.
Innovation Solution
A pressure sensing guidewire with an optical pressure sensor and a contact member that maintains a contact point axially spaced apart from the pressure sensor, minimizing side stress and ensuring accurate pressure readings even when the guidewire is in a deflected position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pressure sensor is positioned close to the distal end of the guidewire for accurate measurement, then measurement precision is improved, but the sensor becomes more susceptible to side stress and stress-induced pressure offsets during steering and navigation
Solution Approach 1:
The contact member extends radially outward from the pressure sensor in a direction perpendicular to the longitudinal axis, creating a spatial separation between the pressure sensing element and the contact point with the tubular member. This dimensional change allows the sensor to maintain axial proximity for accurate measurement while the radial extension prevents direct transmission of side stress to the sensor.
Solution Approach 2:
The contact member acts as an intermediary element between the tubular member and the pressure sensor. It provides a contact point that absorbs and distributes side stress forces, preventing these forces from directly reaching the pressure sensor. The contact member mediates the interaction between the guidewire structure and the sensing element, isolating the sensor from harmful stress transmission.
2Strength
If the contact member is positioned close to the pressure sensor to provide structural support, then device strength is improved, but side stress is transmitted to the pressure sensor causing measurement errors
Solution Approach 1:
The contact member extends radially outward from the pressure sensor in a direction perpendicular to the longitudinal axis, creating a spatial separation between the pressure sensing element and the contact point with the tubular member. This dimensional change allows the sensor to maintain axial proximity for accurate measurement while the radial extension prevents direct transmission of side stress to the sensor.
Solution Approach 2:
The contact member acts as an intermediary element between the tubular member and the pressure sensor. It provides a contact point that absorbs and distributes side stress forces, preventing these forces from directly reaching the pressure sensor. The contact member mediates the interaction between the guidewire structure and the sensing element, isolating the sensor from harmful stress transmission.
3Ease of operation
If the guidewire is made flexible for navigation through vasculature, then ease of operation is improved, but stress-induced pressure offsets increase during steering and tracking
Solution Approach 1:
The contact member acts as an intermediary element between the tubular member and the pressure sensor. It provides a contact point that absorbs and distributes side stress forces, preventing these forces from directly reaching the pressure sensor. The contact member mediates the interaction between the guidewire structure and the sensing element, isolating the sensor from harmful stress transmission.
Solution Approach 2:
The harmful side stress transmission path is extracted and isolated from the pressure sensor through the contact member. The contact member captures and dissipates the side stress forces generated during flexible navigation, removing these harmful forces from the measurement path and allowing accurate pressure sensing despite guidewire flexibility.
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 precise and accurate blood pressure monitoring by reducing side stress-induced pressure shifts, allowing for reliable measurements regardless of the guidewire's position within the vasculature.
Implementation Method 1
an optical pressure sensor attached at a distal end of a fiber optic extending longitudinally within the lumen
Data Source
AI summary
A pressure sensing medical device may include a guidewire including a tubular member having a lumen, the tubular member being translatable between a generally straightened position and a deflected position, and a pressure sensor attached at a distal end of a fiber optic extending within the lumen, the pressure sensor being disposed within a distal portion of the tubular member. The pressure sensor may include a pressure-sensitive membrane disposed on a distal end thereof. The pressure sensor may include one or more contact members capable of providing a contact point between the contact member and an inner surface of the tubular member when in the deflected position, the contact point being axially spaced apart from the membrane along a longitudinal axis of the pressure sensor.