Publications related to Compliance (physiology)

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

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

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

Compliance-matching vascular grafts with personalization potential

Georgios Rovas

Aortic diseases are characterized by dire prognosis and inadequate diagnosis, owing to their insidious yet lethal nature. Aortopathies, namely aortic aneurysms and dissections, along with certain congenital diseases, might necessitate surgical replacement ...

EPFL2023

p-Aminobenzamidine attenuates cardiovascular dysfunctions in spontaneously hypertensive rats

Nikolaos Stergiopoulos, Fabiana Pereira Da Costa Fraga, Allancer Divino De Carvalho Nunes

Aims:Diminazene aceturate, a putative ACE2 activator, is susceptible to cleavage resulting in the formation of paminobenzamidine (PAB). This study aimed to investigate the effects of PAB in addressing cardiovascular dysfunctions in spontaneously hypertensi ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Longitudinal interrogation of sympathetic neural circuits and hemodynamics in preclinical models

Grégoire Courtine, Quentin Barraud, Jordan Squair, Matthieu Pierre Gautier, Victor Perez Puchalt, Loïs Thomas Romain Mahe, Rémi Bernard René Hudelle, Jan Elaine Cuevas Soriano, Suje Amir

Neurological disorders, including spinal cord injury, result in hemodynamic instability due to the disruption of supraspinal projections to the sympathetic circuits located in the spinal cord. We recently developed a preclinical model that allows the ident ...

NATURE PORTFOLIO2022

On the assessment of arterial compliance from carotid pressure waveform

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

In a progressively aging population, it is of utmost importance to develop reliable, noninvasive, and cost-effective tools to estimate biomarkers that can be indicative of cardiovascular risk. Various pathophysiological conditions are associated to changes ...

AMER PHYSIOLOGICAL SOC2021

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

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

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

The impact of heart rate on pulse wave velocity: an in-silico evaluation

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

Background: Clinical and experimental evidence regarding the influence of heart rate (HR) on arterial stiffness and its surrogate marker carotid-to-femoral pulse wave velocity (cf-PWV) is conflicting. We aimed to evaluate the effect of HR on cf-PWV measure ...

LIPPINCOTT WILLIAMS & WILKINS2020

Hemodynamics of ageing, ventricular-arterial coupling and noninvasive assessment of key hemodynamical and cardiac quantities

Stamatia Zoi Pagoulatou

Ageing is a natural process that affects both the anatomical and functional properties of the cardiovascular system and alters the coupling characteristics between the heart and the aorta. These alterations may predispose the cardiovascular system in the d ...

EPFL2020

The effect of the elongation of the proximal aorta on the estimation of the aortic wall distensibility

Nikolaos Stergiopoulos, Georgios Rovas, Bram Trachet, Vasiliki Bikia, Stamatia Zoi Pagoulatou, Mauro Ferraro

The compliance of the proximal aortic wall is a major determinant of cardiac afterload. Aortic compliance is often estimated based on cross-sectional area changes over the pulse pressure, under the assumption of a negligible longitudinal stretch during the ...

2021

Implementation and Calibration of a Deep Neural Network to Predict Parameters of Left Ventricular Systolic Function Based on Pulmonary and Systemic Arterial Pressure Signals

Simone Deparis, Luca Pegolotti, Jean Bonnemain

The evaluation of cardiac contractility by the assessment of the ventricular systolic elastance function is clinically challenging and cannot be easily obtained at the bedside. In this work, we present a framework characterizing left ventricular systolic f ...

2020

Optical Characterization of an Intra-Arterial Light and Drug Delivery System for Photodynamic Therapy of Atherosclerotic Plaque

Hubert van den Bergh, Georges Wagnières, Matthieu Philippe Emmanuel Zellweger, Andreas Pitzschke, Manish Jain, Ying Xiao

Although the versatility of photodynamic therapy (PDT) is well established, the technical aspects of light delivery systems vary significantly depending on the targeted organ. This article describes the optical properties of a light and drug delivery syste ...

2020

Analysis of morphological and haemodynamical indexes in abdominal aortic aneurysms as preliminary indicators of intraluminal thrombus deposition

Alfio Quarteroni, Simone Deparis, Claudia Maria Colciago

In this paper we study the correlation between the Wall Shear Stress (WSS), a haemodynamical index derived from numerical simulations, and an new index MFA-ILT for the characterisation of intraluminal thrombus (ILT) in presence of abdominal aortic aneurysm ...

2020

Reduced Numerical Approximation of Reduced Fluid-Structure Interaction Problems With Applications in Hemodynamics

Simone Deparis, Claudia Maria Colciago

This paper deals with fast simulations of the hemodynamics in large arteries by considering a reduced model of the associated fluid-structure interaction problem, which in turn allows an additional reduction in terms of the numerical discretisation. The re ...

2018

Non-invasive hemodynamic monitoring by electrical impedance tomography

Martin Proença

The monitoring of central hemodynamic parameters such as cardiac output (CO) and pulmonary artery pressure (PAP) is of paramount clinical importance to assess the health status of the cardiovascular system. However, their measurement requires the insertion ...

EPFL2017

Assessment of shear stress related parameters in the carotid bifurcation using mouse-specific FSI simulations

Bram Trachet, Patrick Segers

The ApoE(-/-) mouse is a common small animal model to study atherosclerosis, an inflammatory disease of the large and medium sized arteries such as the carotid artery. It is generally accepted that the wall shear stress, induced by the blood flow, plays a ...

Elsevier Sci Ltd2016

Numerical modeling of heart valves using resistive Eulerian surfaces

Alfio Quarteroni, Aymen Laadhari

The goal of this work is the development and numerical implementation of a mathematical model describing the functioning of heart valves. To couple the pulsatile blood flow with a highly deformable thin structure (the valve's leaflets), a resistive Euleria ...

Wiley-Blackwell2016

Contribution of the Arterial System and the Heart to Blood Pressure during Normal Aging - A Simulation Study

Nikolaos Stergiopoulos, Elira Maksuti, Nico Westerhof

During aging, systolic blood pressure continuously increases over time, whereas diastolic pressure first increases and then slightly decreases after middle age. These pressure changes are usually explained by changes of the arterial system alone (increase ...

Public Library of Science2016

Mathematical and Numerical Modeling of Healthy and Unhealthy Cerebral Arterial Tissues

Paolo Tricerri

Over the last two decades, we have witnessed an increasing application of mathematical models and numerical simulations for the study of the cardiovascular system. Indeed, both tools provide an important contribution to the analysis of the functioning of t ...

EPFL2014

Comparisons between reduced order models and full 3D models for fluid-structure interaction problems in haemodynamics

Alfio Quarteroni, Simone Deparis, Claudia Maria Colciago

When modelling the cardiovascular system, the effect of the vessel wall on the blood flow has great relevance. Arterial vessels are complex living tissues and three-dimensional specific models have been proposed to represent their behaviour. The numerical ...

Elsevier2014

In Vivo Testing of a Novel Adjustable Glaucoma Drainage Device

Nikolaos Stergiopoulos, André Mermoud, Sylvain Roy, Adan Villamarin, Stéphane Bigler

PURPOSE. We report on the in vivo testing of a novel noninvasively adjustable glaucoma drainage device (AGDD), which features an adjustable outflow resistance, and assess the safety and efficiency of this implant. METHODS. Under general anesthesia, the AGD ...

Association for Research in Vision and Ophthalmology2014