Nikolaos Stergiopulos

Education

MTE, Managing the Technology Enterprise Program (2000), IMD, Lausanne

Ph.D. in Biomedical Engineering & Engineering Mechanics (1990) Iowa State University, Ames, Iowa.

MS in Biomedical Engineering (1987) Iowa State University, Ames, Iowa.

Diploma in Mechanical Engineering (1985) National Technical University of Athens.

Professional Activities

2002 - present: Professor and director of LHTC

2010 - present: Founder and director of Rheon Medical SA, Préverenges, Switzerland

2008 - present: Founder and director of Antlia S.A., PSE-C, EPFL campus, Switzerland

1998 - 2007: Founder and Scientific Director of EndoArt S.A., Lausanne, Switzerland

1996 - 2002: Assistant professor at the Biomedical Engineering Laboratory, Swiss Federal Institute of Technology, Lausanne, Switzerland.

1991 - 1996: Research Associate at Swiss Federal Institute of Technology - Lausanne

1990 - 1991: Lecturer, Iowa State University

Cardiac output estimated from an uncalibrated radial blood pressure waveform: validation in an in-silico-generated population

Vasiliki Bikia, Georgios Rovas, Nikolaos Stergiopulos

Background: Cardiac output is essential for patient management in critically ill patients. The state-of-the-art for cardiac output monitoring bears limitations that pertain to the invasive nature of the method, high costs, and associated complications. Hence, the determination of cardiac output in a non-invasive, accurate, and reliable way remains an unmet need. The advent of wearable technologies has directed research towards the exploitation of wearable-sensed data to improve hemodynamical monitoring.Methods: We developed an artificial neural networks (ANN)-enabled modelling approach to estimate cardiac output from radial blood pressure waveform. In silico data including a variety of arterial pulse waves and cardiovascular parameters from 3,818 virtual subjects were used for the analysis. Of particular interest was to investigate whether the uncalibrated, namely, normalized between 0 and 1, radial blood pressure waveform contains sufficient information to derive cardiac output accurately in an in silico population. Specifically, a training/testing pipeline was adopted for the development of two artificial neural networks models using as input: the calibrated radial blood pressure waveform (ANN(calradBP)), or the uncalibrated radial blood pressure waveform (ANN(uncalradBP)).Results: Artificial neural networks models provided precise cardiac output estimations across the extensive range of cardiovascular profiles, with accuracy being higher for the ANN(calradBP). Pearson's correlation coefficient and limits of agreement were found to be equal to [0.98 and (-0.44, 0.53) L/min] and [0.95 and (-0.84, 0.73) L/min] for ANN(calradBP) and ANN(uncalradBP), respectively. The method's sensitivity to major cardiovascular parameters, such as heart rate, aortic blood pressure, and total arterial compliance was evaluated.Discussion: The study findings indicate that the uncalibrated radial blood pressure waveform provides sample information for accurately deriving cardiac output in an in silico population of virtual subjects. Validation of our results using in vivo human data will verify the clinical utility of the proposed model, while it will enable research applications for the integration of the model in wearable sensing systems, such as smartwatches or other consumer devices.

FRONTIERS MEDIA SA2023

Effect of the structural modification of Candesartan with Zinc on hypertension and left ventricular hypertrophy

Valeria Romina Martinez, Augusto Martins Lima, Nikolaos Stergiopulos

Hypertension is the most common cause of left ventricular hypertrophy, contributing to heart failure progression. Candesartan (Cand) is an angiotensin receptor antagonist widely used for hypertension treatment. Structural modifications were previously performed by our group using Zinc (ZnCand) as a strategy for improving its pharmacological properties. The measurements showed that ZnCand exerts a stronger interaction with the angiotensin II receptor, type 1 (AT1 receptor), reducing oxidative stress and intracellular calcium flux, a mechanism implied in cell contraction. These results were accompanied by the reduction of the contractile capacity of mesangial cells. In vivo experiments showed that the complex causes a significant decrease in systolic blood pressure after 8 weeks of treatment in spontaneously hypertensive rats (SHR). The reduction of heart hypertrophy was evidenced by echocardiography, the histologic cross-sectional area of cardiomyocytes, collagen content, the B-type natriuretic peptide (BNP) marker and connective tissue growth factor (CTGF) and the matrix metalloproteinase 2 (MMP-2) expression. Besides, the complex restored the redox status. In this study, we demonstrated that the complexation with Zn(II) improves the antihypertensive and cardiac effects of the parental drug.

ELSEVIER2023

Cardiac output estimated from an uncalibrated radial blood pressure waveform: validation in an in-silico-generated population

Vasiliki Bikia, Georgios Rovas, Nikolaos Stergiopulos

FRONTIERS MEDIA SA2023

Cardiac output estimated from an uncalibrated radial blood pressure waveform: validation in an in-silico-generated population

Effect of the structural modification of Candesartan with Zinc on hypertension and left ventricular hypertrophy

In Memoriam of Nico Westerhof (1937-2022)

Cardiac output estimated from an uncalibrated radial blood pressure waveform: validation in an in-silico-generated population

Effect of the structural modification of Candesartan with Zinc on hypertension and left ventricular hypertrophy

In Memoriam of Nico Westerhof (1937-2022)