https://doi.org/10.1140/epjs/s11734-026-02373-0
Regular Article
Recurrence quantification analysis of photoplethysmography time series for assessing patients with peripheral artery disease
1
PhD Program in Physical Sciences, Universidad Nacional Autónoma de México, Circuito de los Posgrados, Ciudad Universitaria, Coyoacán, 04510, Mexico City, México
2
Department of Physics, Facultad de Ciencias, Universidad Nacional Autónoma de México, Av. Universidad 3000, Circuito Exterior s/n, Ciudad Universitaria, Coyoacán, 04510, Mexico City, México
3
Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Interior, Ciudad Universitaria, Coyoacán, 04510, Mexico City, Mexico
4
Instituto Nacional de Cardiología Ignacio Chávez, Juan Badiano 1, Belisario Domínguez Sección 16, Tlalpan, 14080, Mexico City, México
a
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Received:
31
January
2026
Accepted:
29
April
2026
Published online:
16
May
2026
Abstract
Peripheral artery disease (PAD) is the partial or complete occlusion of the major systemic arteries, and its diagnosis is commonly assessed using the ankle–brachial index (ABI). However, ABI is limited by arterial compressibility and is considered operator-dependent. Given the importance of early diagnosis for better outcomes and the complexity of PAD management, studying complementary tests and PAD’s mechanisms might help in its assessment. Photoplethysmography (PPG) is a low-cost, non-invasive technique that does not have arterial compressibility as a limitation and requires no advanced training to implement. The mean and standard deviation of PPG morphological parameters (pulse transit time, maximum systolic slope and pulse amplitude) have been studied before for PAD patients, but their non-linear dynamics have not been assessed. In this work, we performed recurrence quantification analysis (RQA) of PPG morphological parameters. A total of 40 legs from PAD patients with compressible ABI were studied for general description and to explore the relationship between PPG RQA indices and ABI. It was shown that RR interval dynamics differed from those of PPG-derived parameters despite their shared regulatory mechanisms. The central tendency and general variability of the PPG-derived parameters are related to changes in their dynamical states, which can increase or decrease their predictability, stationarity, or complexity. However, they do not clearly relate to PAD progression or PAD diagnosis. Further studies are needed, considering the results of this work and its limitations, to continue exploring the interesting PPG dynamics for a broader number of groups with different physiological conditions.
© The Author(s) 2026
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