Microcatheter Sensor Isolation via Flexible Wire
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Solution Overview
Problem
Conventional microcatheters face challenges in accurately measuring pressure gradients across vessel lesions due to bending stresses on pressure sensors, which can lead to distorted readings and require the use of specialized FFR guidewires, limiting their application in interventional procedures.
Innovation Solution
A microcatheter design featuring an elongate shaft with separate lumens for a guidewire and pressure sensor wire, along with a flexible interconnect or gap to isolate the pressure sensor, minimizes bending stresses and allows independent movement, enabling accurate pressure measurements while allowing the use of conventional guidewires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is mounted on the distal end of a microcatheter, then pressure measurements can be obtained, but bending stresses from interaction with the catheter housing cause sensor distortion and incorrect readings
Solution Approach 1:
The catheter is divided into separate functional components: a flexible wire extends through the catheter shaft to the distal tip, while the pressure sensor is mounted on the catheter housing. This segmentation allows the sensor to be isolated from bending stresses that affect the flexible wire, enabling accurate pressure measurements without sensor distortion.
Solution Approach 2:
A flexible wire acts as an intermediary element between the pressure sensor and the distal tip. The wire transmits pressure forces to the sensor while allowing independent movement, thereby isolating the sensor from bending stresses caused by catheter-housing interaction.
2Measurement precision
If a pressure sensor is mounted on the distal end of a catheter, then pressure measurements can be obtained, but the catheter profile increases and bending stresses are amplified
Solution Approach 1:
By separating the pressure sensor mounting from the distal tip and using a flexible wire to transmit pressure forces, the design allows the catheter shaft to maintain a thin profile while the sensor is positioned on the housing where it can be isolated from bending stresses.
Solution Approach 2:
The rigid mechanical connection between the distal tip and sensor is replaced with a flexible wire that can bend and move independently. This substitution allows the catheter to maintain a thin profile while the flexible wire transmits pressure forces without transmitting bending stresses to the sensor.
3Measurement precision
If conventional FFR guidewires are used, then accurate pressure measurements can be obtained, but the guidewires are not desired by clinicians for interventional procedures
Solution Approach 1:
The catheter is designed to work with both conventional guidewires and FFR guidewires. The flexible wire and pressure sensor configuration allow the system to accommodate different guidewire types, making it universally applicable for both diagnostic pressure measurements and interventional procedures.
Solution Approach 2:
The catheter design allows clinicians to use their preferred conventional guidewires without requiring specialized FFR guidewires. The flexible wire and sensor configuration enable accurate measurements regardless of which guidewire type is used, putting the system in control rather than requiring specific guidewire specifications.
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
This design enhances the accuracy of pressure measurements, reduces the catheter profile, and allows for the use of conventional guidewires, improving the reliability of Fractional Flow Reserve calculations and facilitating interventional treatments.
Implementation Method 1
a pressure sensor mounted on the distal tip for measuring a pressure of a fluid within lumen of vessel
Data Source
AI summary
A catheter, such as a fractional flow reserve catheter, includes an elongate shaft having a pressure sensing wire extending to the distal portion of the elongate shaft. The wire has a pressure sensor mounted on the distal end for measuring a pressure of a fluid within lumen of vessel. The pressure sensor wire is disposed within a pocket formed adjacent to the pressure sensor thereby minimizing the profile of the catheter. Bending stresses experienced by a pressure sensor mounted to a fractional flow reserve catheter when tracking the catheter through the vasculature creates a distortion of the sensor resulting in an incorrect pressure reading or bend error. In order to isolate the sensor from bending stresses, the sensor is spaced apart from the pressure sensor wire to allow the pressure sensor and the pressure sensor wire to move independently from one another.