Estimating Pulse Wave Velocity from PPG Signals Using Weighted Visibility Graphs

Our team, in collaboration with researchers from Alfaisal University, Sorbonne Université and Sensoria Analytics, has contributed to a new study published in Scientific Reports journal that introduces a novel way to estimate pulse wave velocity (PWV).
This study proposes a novel data-driven approach for PWV estimation using features derived from Limited Penetrable Weighted Visibility Graphs (LPWVGs) constructed from photoplethysmography (PPG) waveforms and their first and second derivatives. By generating multiple LPWVGs with diverse weighting strategies, we capture the PPG signal’s rich temporal and morphological characteristics. A wide range of features was extracted, including descriptors from two-dimensional Semi-Classical Signal Analysis (SCSA), frequency-domain features, and morphological shape and local variation metrics. These were used to train an Explainable Boosting Machine (EBM), a glass-box machine learning model combining strong predictive power and interpretability.The proposed method was evaluated using positive and negative testing on real multicycle PPG datasets. The results demonstrate high accuracy and robustness,with an R2 = 0.91 and RM SE = 0.34 in the positive test and a RMSE = 1.49 for the negative test. These results support the feasibility of this approach for non-invasive PWV estimation in clinical and ambulatory settings, with potential applications in cardiovascular disease screening, risk stratification, and aging research.

Pulse wave velocity estimation based on Limit Penetrable Weighted Visibility Graph (LPWVG) and image processing feature extraction wave images. The proposed framework takes the signal obtained from the radial artery and computes the first two derivatives. Then, the three signals are transformed into images using a visibility graph and the different weights proposed. Finally, for each image, a set of three different types of features based on shape, texture, and energy are extracted and fed into an EBM (Explainable Boosting Machine) to estimate the PWV.

For more information about the article, you can enter to the following link:
Scientific Reports article