Cardiac Pressure Equalization Using a Pressure Wire Reference
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Solution Overview
Problem
Existing fluid-filled catheters for cardiovascular pressure measurements suffer from errors due to oscillations, damping, and timing differences, which affect the accuracy of phasic pressure assessments, particularly in high-fidelity pressure wire sensors, leading to potential adverse clinical outcomes in interventions like coronary revascularization or valve implantation.
Innovation Solution
A method and system that uses a high-fidelity pressure wire as a reference to correct fluid-filled catheter measurements by applying a series of equalization parameters, including frequency, damping, offset, timing, and gain corrections, and deconvolution to align the pressure signals, enhancing their fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluid-filled catheter is used for pressure measurement, then the measurement can be made with access through a catheter, but errors occur due to oscillations, damping, and timing differences affecting accuracy
Solution Approach 1:
A pressure wire sensor is introduced as an intermediary reference device to provide a reliable reference pressure measurement. The fluid-filled catheter measurements are then equalized against this reference, allowing the catheter to function reliably despite its inherent oscillations and damping characteristics.
Solution Approach 2:
Multiple correction parameters are applied to transform the catheter pressure signal: frequency correction parameter adjusts oscillation frequency, damping correction parameter compensates for signal damping, offset correction parameter aligns baseline levels, timing correction parameter synchronizes phase, and gain correction parameter matches amplitude. These parameter transformations convert the unreliable catheter signal into an accurate measurement.
2Measurement precision
If equalization parameters are applied to correct fluid-filled catheter measurements, then measurement accuracy improves, but device complexity increases due to multiple correction parameters and deconvolution processing
Solution Approach 1:
The equalization parameters are determined in advance during a calibration phase when both the pressure wire and fluid-filled catheter are positioned at a calibration location. This preliminary characterization of the catheter's frequency response and damping properties allows subsequent measurements to be corrected using pre-computed parameters, reducing real-time processing complexity.
Solution Approach 2:
The pressure wire sensor creates a reference copy of the true pressure signal. By comparing the catheter signal against this reference copy and determining equalization parameters, the system can apply corrections to future catheter measurements without requiring the pressure wire to be continuously present, simplifying the overall measurement process.
Data Source
AI summary
A method for measuring cardiac pressure includes positioning a fluid-filled catheter and a pressure wire sensor at a cardiac pressure calibration location. A first pressure measurement is acquired from the fluid-filled catheter and a second pressure measurement is acquired from the pressure wire sensor. A set of equalization parameters is identified to apply to the first pressure measurement to reduce an error between the first pressure measurement and the second pressure measurement. The equalization parameters include a frequency correction parameter and a damping correction parameter to correct for frequency and damping of oscillations in the first pressure measurement. A third pressure measurement is acquired from the fluid-filled catheter. The set of equalization parameters is applied to equalize the third pressure measurement.