Arterial Stiffness Index Calculation Using Pulse Waveform Decomposition
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Solution Overview
Problem
Existing methods for determining arterial stiffness index from radial pulse waveforms are computationally demanding and prone to noise errors due to the proximity and amplitude differences of early and late systolic peaks, as well as noise sensitivity in measurement sites.
Innovation Solution
A method involving the estimation of a source pulse based on predetermined features, decomposition of the pulse waveform into components, and calculation of the arterial stiffness index using impulse response segmentation and convolution, reducing computational demand and noise sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If curve fitting method is used to decompose radial pulse waveform, then measurement precision of arterial stiffness index is improved, but device complexity and computation demand increase significantly
Solution Approach 1:
The patent segments the radial pulse waveform into distinct components (early systolic peak, late systolic peak, dicrotic notch) based on temporal and amplitude characteristics. By dividing the complex waveform into separable segments with identifiable features, the method avoids the need for iterative curve fitting while maintaining accurate component separation and stiffness index calculation.
2Measurement precision
If derivative-based classification is used to identify waveform features, then measurement precision is improved, but reliability decreases due to noise amplification
Solution Approach 1:
Instead of applying derivative operations to enhance feature detection (which amplifies noise), the patent inverts the approach by using integration or direct waveform analysis methods that inherently suppress high-frequency noise while preserving the underlying pulse wave morphology and key features.
Solution Approach 2:
The patent introduces an intermediary smoothing filter or envelope detection mechanism that mediates between the raw noisy signal and the feature extraction process, allowing accurate identification of peaks and inflection points without directly amplifying noise through differentiation.
3Ease of operation
If radial pulse waveform is measured at certain sites, then ease of operation is improved, but measurement precision deteriorates due to noise and weak signal
Solution Approach 1:
The patent compensates for signal degradation at peripheral measurement sites by analyzing multiple dimensions of the pulse waveform simultaneously (amplitude, timing, morphology features) rather than relying on a single strong signal characteristic, thereby maintaining measurement precision despite weaker signals.
Data Source
AI summary
A method of determining stiffness index of an arterial network is disclosed. The method comprises the steps of: obtaining a pulse waveform related to the arterial network; estimating a source pulse based on at least one predetermined feature of the pulse waveform; determining a plurality of characteristics of the pulse waveform based on a relationship between the pulse waveform and the source pulse; and calculating the stiffness index of the arterial network based on the plurality of characteristics of the pulse waveform. An arterial stiffness index measuring device employing the above methodology is also disclosed therein.