🤖 AI Summary
This study addresses the challenge of detecting subtle, age-related morphological changes in arterial pulse waveforms to facilitate early assessment of cardiovascular health risks. To this end, it introduces a novel approach that, for the first time, integrates Symmetric Projection Attractor Reconstruction (SPAR) with convolutional neural networks to transform pulse wave time series—acquired via photoplethysmography (PPG) and arterial tonometry—into image representations. These SPAR-derived images are employed to discriminate between adjacent age groups (35–40 years versus 50–55 years) within a healthy population. The method achieves F1 scores exceeding 70% on both internal and external test sets, demonstrating that SPAR effectively encodes discriminative age-related features. This work thus establishes a new paradigm for non-invasive vascular age estimation.
📝 Abstract
Arterial pulse waveform morphology evolves with age, reflecting structural and functional changes in the cardiovascular system. Thus, vascular age is a valuable surrogate marker of cardiovascular health, and premature vascular ageing can indicate increased disease risk. Pulse wave analysis could support risk stratification in otherwise asymptomatic adults. We transformed pulse wave time-series data from photoplethysmography (PPG) and arterial tonometry into images, using the Symmetric Projection Attractor Reconstruction (SPAR) method. These SPAR images were used to train a convolutional neural network to classify healthy subjects into two closely spaced age groups (35-40 and 50-55 years). The model demonstrated consistent classification performance across internal and external test sets, achieving F1 scores above 70% for both PPG and tonometry signals. These results suggest that SPAR-derived pulse wave images contain discriminative morphological features even among healthy adults close in age. This proof-of-concept lays the groundwork for future research into the use of SPAR for early risk detection using smart wearables.