VascAgeNet Photoplethysmography Group

Overview

Vascular ageing is a natural process by which the function and structure of blood vessels degrade over time. It can manifest as elevated blood pressure, increased arterial stiffness, and atherosclerosis. Current approaches to assess vascular age have been found to be predictive of cardiovascular morbidity and mortality, but are often not convenient enough for widespread use.

This group of European researchers is investigating the use of photoplethysmography to assess vascular age. Photoplethysmography is a non-invasive optical technique for measuring the arterial pulse wave, providing information on the state of the heart and blood vessels. The group is part of the wider VascAgeNet network.

Work to date

The group have co-authored several publications:

Group papers

• Assessing hemodynamics from the photoplethysmogram to gain insights into vascular age: A review from VascAgeNet: A review of techniques to assess vascular age from the photoplethysmogram. Co-authored by 16 researchers from 11 countries.
• Establishing best practices in photoplethysmography signal acquisition and processing: An editorial on whether it would be possible and beneficial to establish best practices for photoplethysmography signal acquisition and processing. Co-authored by 3 group members.

Collaborative research

• Blood Pressure Estimation Based on Photoplethysmography: Finger versus Wrist: Comparing blood pressure estimates obtained from finger and wrist sensors.

Collaborative reviews

• Wearable photoplethysmography devices: A comprehensive overview of the state-of-the-art of wearable photoplethysmography devices.
• Wearable photoplethysmography for cardiovascular monitoring: A review of wearable photoplethysmgoraphy, considering the technology, signal processing, and clinical applications.

Invited Talks

The following speakers gave invited talks to the group in 2021:

• Kevin Kotzen: Benchmarking Photoplethysmography Peak Detection Algorithms Using the Electrocardiogram Signal as a Reference, 7 October 2021. Accompanying paper
• Birute Paliakaite: Blood Pressure Estimation Based on Photoplethysmography: Finger versus Wrist, 28 October 2021. Accompanying paper
• Wan-Hua Lin (Shenzhen Institute of Advanced Technology, Chinese Academy of Science, China): Investigating the physiological mechanisms of the photoplethysmogram features for blood pressure estimation, 18 November 2021. Accompanying paper
• Philip Aston (National Physical Laboratory, UK): 9 December 2021.

In 2022 group members have given talks in a public webinar series on Photoplethysmography, including:

• John Allen: presented on Further explorations in photoplethysmography for the detection of occlusive peripheral arterial disease.
• Panicos Kyriacou: presented on Non-invasive optical monitoring of Intracranial Pressure in Traumatic Brain Injury patients.
• Serena Zanelli: will present on Deep learning approach to detect signal quality from clinical to non-clinical PPG devices. Accompanying paper

Short-Term Scientific Mission

Dr Peter Charlton spent 5 days at Kaunas University of Technology (KTU), hosted by Prof Vaidotas Marozas, Director of the Institute of Biomedical Engineering. During this STSM, Vaidotas, Peter and Birute Paliakaite worked with colleagues at KTU towards harmonising photoplethysmography-based techniques for the assessment of vascular ageing. This was funded by VascAgeNet.

Group Members

The work of the group would not be possible without the hard work of its members, who include:

• Dr Peter Charlton is a Biomedical Engineer specialising in signal processing techniques for the photoplethysmogram (PPG), including estimating respiratory rate and assessing vascular age from the PPG. He presently holds a British Heart Foundation Fellowship at the University of Cambridge.
• Birute Paliakaite is a researcher specialising in PPG signal processing and modelling, and has made key contributions on acquiring haemodynamic parameters from wearables, and detecting and modelling arrhythmias in the PPG.
• Dr Kristjan Pilt has developed novel techniques to assess vascular age from the PPG in his research, and has demonstrated their potential clinical utility in diabetic patients.
• Dr Martin Bachler is a research engineer in the field of clinical diagnostics and therapy support, and specialises in biomedical signal analysis.
• Serena Zanelli develops machine learning and deep learning models to detect cardiovascular disease from PPG signals acquired by wearables, working in both academic and clinical settings.
• Dr Daniel Kulin is a medical doctor, researcher and entrepreneur in the field of PPG-based pulse wave analysis and in the development of remote patient monitoring systems.
• Prof John Allen is a leading researcher in the field of photoplethysmography. He has worked on assessing vascular age from the PPG for approximately 30 years. He has strong experience on developing PPG-based techniques, and translating them towards clinical practice. His seminal review on photoplethysmography has been cited over 3,000 times.
• Dr Magid Hallab is a physician, inventor of pOpmetre, a device for PPG-based pulse wave velocity measurement, and CEO of Axelife, the company who sell the pOpmetre device.
• Dr Elisabetta Bianchini works in the field of ultrasound imaging and cardiovascular bioengineering, with strong interests in technology transfer.
• Dr Christopher Mayer conducts research in the field of biomedical signal processing, including simulation and pulse wave analysis.
• Dr Dimitrios Terentes-Printzios is a Cardiologist with research interests in hypertension and microvascular dysfunction. He conducted his PhD on vascular ageing and has co-organised and large multicentre studies.
• Verena Dittrich is Co-Founder and CEO of Redwave Medical, a company specialising in algorithms for cardiovascular assessment.
• Dr Bernhard Hametner is a mathematician developing methods for pulse wave analysis, and is involved in the analysis of cardiovascular parameters obtained in clinical studies.
• Mr Dave Veerasingam is a Consultant Cardiothoracic Surgeon, and is involved in the cardiac Medtech industry. His research interests include the association between vascular ageing and target organ damage.
• Dr Dejan Zikic is an Associate Professor in Biophysics, with research interests including modelling pulse wave propagation and pulse wave analysis.
• Dr Vaidotas Marozas is Director of the Biomedical Engineering Institute at Kaunas Institute of Technology, and has conducted research into PPG modelling, analysis, and acquisition using wearables.