Intravascular Sensing System Corrected FFR Calculation
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Solution Overview
Problem
Current pressure sensing guidewires used for measuring Fractional Flow Reserve (FFR) in blood vessels introduce errors due to their cross-sectional size, leading to exaggerated pressure gradients and potentially inaccurate treatment decisions, as they must be maneuvered across stenotic lesions, which can be difficult and time-consuming, especially in complex anatomical structures.
Innovation Solution
A system that includes a pressure sensing device with a sensor delivery device and a processor to calculate a corrected FFR by applying a correction factor or equation to blood pressure measurements, accounting for the cross-sectional area of the device and patient physiology, thereby approximating the FFR measurement that would be obtained without the device or with a standard 0.014 inch guidewire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensing guidewire is used to measure FFR, then pressure measurements can be obtained, but measurement errors occur due to the device's cross-sectional size causing exaggerated pressure gradients
Solution Approach 1:
The patent replaces the mechanical pressure sensing guidewire with an optical sensing system. An optical sensor detects pressure-induced changes in optical properties (such as refractive index or optical path length) of the surrounding tissue or fluid, converting mechanical pressure measurement into an optical measurement that does not require physical contact with the tissue, thereby eliminating the mechanical obstruction effect
Solution Approach 2:
The patent introduces an intermediary medium (such as contrast agent or optical probe) that transmits pressure information from the measurement site to the sensor without requiring the sensor to be in direct contact with the tissue. This intermediary allows pressure detection while minimizing the physical presence of the sensing device in the vessel
2Measurement precision
If a pressure sensing guidewire is maneuvered across stenotic lesions, then FFR measurements can be obtained, but the procedure becomes difficult and time-consuming
Solution Approach 1:
The patent integrates multiple functions into a single catheter system that can perform both angiographic imaging and pressure measurement simultaneously. The system includes contrast injection capability, optical sensing, and pressure detection in one device, eliminating the need to separately maneuver a pressure sensing guidewire across lesions and reducing procedural steps
Solution Approach 2:
The patent combines the pressure sensing functionality with the existing catheter-based angiography system. By merging the optical sensor and pressure detection elements into the catheter that is already being used for imaging, the system eliminates the need for separate guidewire manipulation and reduces the overall procedure time
3Measurement precision
If a pressure sensing guidewire is used, then FFR measurements can be obtained, but the device's presence causes exaggerated pressure gradients and inaccurate treatment decisions
Solution Approach 1:
The patent replaces the mechanical pressure sensing guidewire with an optical sensing system. An optical sensor detects pressure-induced changes in optical properties (such as refractive index or optical path length) of the surrounding tissue or fluid, converting mechanical pressure measurement into an optical measurement that does not require physical contact with the tissue, thereby eliminating the mechanical obstruction effect
Solution Approach 2:
The patent changes the measurement parameter from direct mechanical contact pressure sensing to optical property detection. By measuring changes in optical properties (refractive index, optical path length) that are induced by pressure, the system obtains pressure information without the mechanical presence that causes flow obstruction
Data Source
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AI summary
Methods and systems for calculating a corrected Fractional Flow Reserve. Methods include delivering a pressure sensing device including a pressure sensor to a location in an artery having a stenosis, positioning the pressure sensor distal to the stenosis, measuring the distal pressure, measuring the proximal pressure, and calculating a corrected Fractional Flow Reserve using the measured proximal and distal pressures. A correction factor or correction equation corrects for changes in the measured distal pressure caused by a presence of the pressure sensing device. A data set of correction factors or correction equations may be stored in a memory component of the system. The corrected Fractional Flow reserve may approximate the Fractional Flow Reserve that would be obtained if a different sized device was used to measure the distal pressure, such as a pressure sensing guidewire having a 0.014 inch outer diameter. 5134726