Coronary Pressure Waveform Assessment Without Dicrotic Notch Detection
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Solution Overview
Problem
Existing Fractional Flow Reserve (FFR) measurement techniques for assessing stenosis severity in blood vessels rely on identifying the dicrotic notch, which can be difficult to detect, leading to inaccurate approximations and increased patient side effects due to the need for pharmacological hyperemia.
Innovation Solution
A method for assessing FFR without hyperemia by identifying leading and trailing characteristics in pressure measurements at different locations in the vessel, such as maximum pressure measurements, to calculate a pressure ratio, eliminating the need to detect the dicrotic notch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional FFR measurement uses pharmacological hyperemia to minimize coronary resistance, then measurement accuracy is improved, but patient side effects and treatment cost increase
Solution Approach 1:
The patent extracts the essential requirement of minimized coronary resistance from the hyperemia process by identifying and utilizing the natural diastole period when resistance is already low, eliminating the need for pharmacological agents while maintaining measurement accuracy
Solution Approach 2:
The patent performs preliminary identification of the dicrotic notch and diastole period from pressure waveforms before taking measurements, ensuring that measurements are taken during the optimal time window when coronary resistance is naturally minimized
2Loss of time
If FFR approximation identifies dicrotic notch to define diastole period, then measurement timing is improved, but detection difficulty and measurement accuracy worsen due to difficult notch detection
Solution Approach 1:
The patent uses the dicrotic notch as an intermediary marker to identify the start of diastole, but provides backup methods using alternative characteristics (maximum pressure points, inflection points) when the intermediary is not detectable, ensuring measurement timing can be established through multiple pathways
3Measurement precision
If FFR approximation uses dicrotic notch-based diastole period definition, then pressure measurement timing is improved, but measurement accuracy worsens when dicrotic notch is not discernable
Solution Approach 1:
The patent changes the reference parameter for defining diastole period from dicrotic notch detection to alternative pressure waveform characteristics such as maximum pressure points and inflection points, allowing the system to adapt when the original parameter cannot be reliably detected
Data Source
AI summary
One method for assessing a vessel can include obtaining a set of first location pressure measurements at a first location in the vessel over a first time period and a set of second location pressure measurements at a second location in the vessel over the first time period. This method can further include identifying a first leading characteristic associated with one or more pressure measurements in the set of first location pressure measurements, a second leading characteristic associated with one or more pressure measurements in the set of second location pressure measurements, a first trailing characteristic associated with one or more pressure measurements in the set of first location pressure measurements, and a second trailing characteristic associated with one or more pressure measurements in the set of second location pressure measurements. And, this method can include calculating a pressure ratio using pressure measurements between the identified characteristics.