Publications by Vasiliki Bikia

Testing an inverse modeling approach with gradient boosting regression for stroke volume estimation using patient thermodilution data

Nikolaos Stergiopoulos, Vasiliki Bikia, Georgios Rovas

Stroke volume (SV) is a major indicator of cardiovascular function, providing essential information about heart performance and blood flow adequacy. Accurate SV measurement is particularly important for assessing patients with heart failure, managing patie ...

FRONTIERS MEDIA SA2025

Evaluation of a novel compliance-matching aortic graft in a swine model

Nikolaos Stergiopoulos, Vasiliki Bikia, Georgios Rovas

The mismatch of elastic properties between the arterial tissue and the vascular grafts, commonly called compliance mismatch, is responsible for many deleterious post-operative complications. Currently, there is an absence of prostheses that conform with th ...

2025

Developing Technologies to Assess Vascular Ageing: a Roadmap From Vascagenet

Vasiliki Bikia

Vascular ageing (vascular ageing) is the deterioration of arterial structure and function which occurs naturally with age, and which can be accelerated with disease. Measurements of vascular ageing are emerging as markers of cardiovascular risk, with poten ...

IOP Publishing Ltd2024

Novel theory and potential applications of central diastolic pressure decay time constant

Nikolaos Stergiopoulos, Patrick Segers, Vasiliki Bikia, Georgios Rovas, Sokratis Anagnostopoulos

Central aortic diastolic pressure decay time constant ( ) is according to the two-element Windkessel model equal to the product of total peripheral resistance (R) times total arterial compliance (C ). As such, it is related to arterial stiffness, which has ...

2024

Apparatus for non-invasively computing cardio-vasculature parameters using morphology of uncalibrated pressure wave signal

Nikolaos Stergiopoulos, Vasiliki Bikia, Georgios Rovas

Systems and apparatus are provided for using a non-invasively monitored uncalibrated pressure signal from a patient to compute cardiac output and other cardio-vascular parameters, thereby providing safe, effective, reliable and low cost monitoring of patie ...

2024

Method and apparatus for non-invasively computing cardio-vasculature parameters using morphology of uncorrelated pressure wave signal

Nikolaos Stergiopoulos, Vasiliki Bikia

[0054] Methods are provided for estimating key reliably and accurately predicting cardiac output using a limited set of non-invasively monitored physiologic inputs, and a calibrated one- dimensional arterial tree model, a database of synthetic data generat ...

2024

In Silico Validation of Non-Invasive Arterial Compliance Estimation and Potential Determinants of its Variability

Nikolaos Stergiopoulos, Vasiliki Bikia

Arterial compliance (AC) is an important cardiovascular parameter characterizing mechanical properties of arteries. AC is significantly influenced by arterial wall structure and vasomotion, and it markedly influences cardiac load. A new method, based on a ...

2024

On the similarity between aortic and carotid pressure diastolic decay: a mathematical modelling study

Nikolaos Stergiopoulos, Vasiliki Bikia, Georgios Rovas, Sokratis Anagnostopoulos

Aortic diastolic pressure decay (DPD) has been shown to have considerable pathophysiological relevance in the assessment of vascular health, as it is significantly affected by arterial stiffening. Nonetheless, the aortic pressure waveform is rarely availab ...

Nature Portfolio2023

Design and computational optimization of compliance-matching aortic grafts

Nikolaos Stergiopoulos, Vasiliki Bikia, Georgios Rovas

Introduction: Synthetic vascular grafts have been widely used in clinical practice for aortic replacement surgery. Despite their high rates of surgical success, they remain significantly less compliant than the native aorta, resulting in a phenomenon calle ...

FRONTIERS MEDIA SA2023

Arterial pulse wave modeling and analysis for vascular-age studies: a review from VascAgeNet

Patrick Segers, Vasiliki Bikia

Arterial pulse waves (PWs) such as blood pressure and photoplethysmogram (PPG) signals contain a wealth of information on the cardiovascular (CV) system that can be exploited to assess vascular age and identify individuals at elevated CV risk. We review th ...

AMER PHYSIOLOGICAL SOC2023

Quantification of the Phenomena Affecting Reflective Arterial Photoplethysmography

Nikolaos Stergiopoulos, Vasiliki Bikia, Georgios Rovas

Photoplethysmography (PPG) is a widely emerging method to assess vascular health in humans. The origins of the signal of reflective PPG on peripheral arteries have not been thoroughly investigated. We aimed to identify and quantify the optical and biomecha ...

MDPI2023

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

Nikolaos Stergiopoulos, Vasiliki Bikia, Georgios Rovas

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. Hen ...

FRONTIERS MEDIA SA2023

Assessment Of Stiffness Of Large To Small Arteries In Multi-Stage Renal Disease: A Numerical Study

Nikolaos Stergiopoulos, Patrick Segers, Vasiliki Bikia

LIPPINCOTT WILLIAMS & WILKINS2022

Prognostic Implications of the Novel Pulmonary Hypertension Definition in Patients with Aortic Stenosis after Transcatheter Valve Replacement

Nikolaos Stergiopoulos, Stamatia Zoi Pagoulatou, Vasiliki Bikia, Georgios Rovas

Introduction: Pulmonary hypertension (PH), traditionally defined as a mean pulmonary artery pressure (PAP) >= 25 mmHg, is associated with poor outcomes in patients undergoing a transcatheter aortic valve replacement (TAVR) for severe aortic stenosis (AS). ...

MDPI2022

Pre-interventional pulmonary hypertension predicts mortality in patients with aortic stenosis after transcatheter aortic valve replacement. A definition update

Nikolaos Stergiopoulos, Stamatia Zoi Pagoulatou, Vasiliki Bikia, Georgios Rovas

E M H SWISS MEDICAL PUBLISHERS LTD2022

Validation of a Non-invasive Inverse Problem-Solving Method for Stroke Volume

Nikolaos Stergiopoulos, Stamatia Zoi Pagoulatou, Emma Marie Roussel, Vasiliki Bikia, Georgios Rovas

Stroke volume (SV) is a major biomarker of cardiac function, reflecting ventricular-vascular coupling. Despite this, hemodynamic monitoring and management seldomly includes assessments of SV and remains predominantly guided by brachial cuff blood pressure ...

FRONTIERS MEDIA SA2022

Arterial Wave Reflection and Aortic Valve Stenosis: Diagnostic Challenges and Prognostic Significance

Nikolaos Stergiopoulos, Stamatia Zoi Pagoulatou, Vasiliki Bikia, Georgios Rovas

IntroductionArterial wave reflection is an important component of the left ventricular afterload, affecting both pressure and flow to the aorta. The aim of the present study was to evaluate the impact of wave reflection on transvalvular pressure gradients ...

FRONTIERS MEDIA SA2022

Assessment of Stiffness of Large to Small Arteries in Multistage Renal Disease Model: A Numerical Study

Nikolaos Stergiopoulos, Patrick Segers, Vasiliki Bikia

Arterial stiffness (AS), as assessed via pulse wave velocity (PWV), is a major biomarker for cardiovascular risk assessment in patients with chronic kidney disease (CKD). However, the mechanisms responsible for the changes in PWV in the presence of kidney ...

FRONTIERS MEDIA SA2022

AI-Based Estimation of End-Systolic Elastance From Arm-Pressure and Systolic Time Intervals

Nikolaos Stergiopoulos, Stamatia Zoi Pagoulatou, Vasiliki Bikia, Georgios Rovas

Left ventricular end-systolic elastance (Ees) is a major determinant of cardiac systolic function and ventricular-arterial interaction. Previous methods for the Ees estimation require the use of the echocardiographic ejection fraction (EF). However, given ...

2021

In vivo application and validation of a novel noninvasive method to estimate the end-systolic elastance

Nikolaos Stergiopoulos, Stamatia Zoi Pagoulatou, Vasiliki Bikia, Georgios Rovas

Accurate assessment of the left ventricular (LV) systolic function is indispensable in the clinic. However, estimation of a precise index of cardiac contractility, i.e., the end-systolic elastance (E-es), is invasive and cannot be established as clinical r ...

2021