Publications related to Preload (cardiology)

Hemodynamic effects of a dielectric elastomer augmented aorta on aortic wave intensity: An in-vivo study

Yves Perriard, Yoan René Cyrille Civet, Thomas Guillaume Martinez, Francesco Clavica, Armando Matthieu Walter, Silje Ekroll Jahren, Lorenzo Ferrari

Dielectric elastomer actuator augmented aorta (DEA) represents a novel approach with high potential for assisting a failing heart. The soft tubular device replaces a section of the aorta and increases its diameter when activated. The hemodynamic interactio ...

2023

The Impact of Left Ventricular Performance and Afterload on the Evaluation of Aortic Valve Stenosis: A 1D Mathematical Modeling Approach

Nikolaos Stergiopoulos

The transaortic valvular pressure gradient (TPG) plays a central role in decision-making for patients suffering from severe aortic stenosis. However, the flow-dependence nature of the TPG makes the diagnosis of aortic stenosis challenging since the markers ...

MDPI2023

A novel soft cardiac assist device based on a dielectric elastomer augmented aorta: An in vivo study

Yves Perriard, Yoan René Cyrille Civet, Thomas Guillaume Martinez, Francesco Clavica, Armando Matthieu Walter, Jonathan André Jean-Marie Chavanne, Silje Ekroll Jahren, Lorenzo Ferrari

Although heart transplant is the preferred solution for patients suffering from heart failures, cardiac assist devices remain key substitute therapies. Among them, aortic augmentation using dielectric elastomer actuators (DEAs) might be an alternative tech ...

2022

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

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

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

Noninvasive Cardiac Output and Central Systolic Pressure From Cuff-Pressure and Pulse Wave Velocity

Nikolaos Stergiopoulos, Bram Trachet, Vasiliki Bikia, Stamatia Zoi Pagoulatou

Goal: We introduce a novel approach to estimate cardiac output (CO) and central systolic blood pressure (cSBP) from noninvasive measurements of peripheral cuff-pressure and carotid-to-femoral pulse wave velocity (cf-PWV). Methods: The adjustment of a previ ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2020

Total arterial compliance, estimated by a novel method, is better related to left ventricular mass compared to aortic pulse wave velocity: The SAFAR study

Nikolaos Stergiopoulos

Aim: The investigation of the association between total arterial compliance (C-T)-estimated by a novel technique-with left ventricular mass (LVM) and hypertrophy (LVH). Our hypothesis was that C-T may be better related to LVM compared to the gold-standard ...

Taylor & Francis Inc2017

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

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

Influence of heart motion on cardiac output estimation by means of electrical impedance tomography: a case study

Jean-Philippe Thiran, Mathieu Lemay, Fabian Braun, Martin Proença, Michaël Rapin

Electrical impedance tomography (EIT) is a non-invasive imaging technique that can measure cardiac-related intra-thoracic impedance changes. EIT-based cardiac output estimation relies on the assumption that the amplitude of the impedance change in the vent ...

Iop Publishing Ltd2015

Automated multi-parameter measurement of cardiomyocytes dynamics with digital holographic microscopy

Gerardo Turcatti, Benjamin Rappaz, Pierre Marquet

Compounds tested during drug development may have adverse effects on the heart; therefore all new chemical entities have to undergo extensive preclinical assessment for cardiac liability. Conventional intensity-based imaging techniques are not robust enoug ...

Optical Society of America2015

Impact of HSD11B1 polymorphisms on BMI and components of the metabolic syndrome in patients receiving psychotropic treatments

Pierre Magistretti, Murielle Bochud, Aurélie Delacrétaz

Background Metabolic syndrome (MetS) associated with psychiatric disorders and psychotropic treatments represents a major health issue. 11 beta-Hydroxysteroid dehydrogenase type 1 (11 beta-HSD1) is an enzyme that catalyzes tissue regeneration of active cor ...

Lippincott Williams & Wilkins2015

Brachial artery waveforms for automatic blood pressure measurement

Nikolaos Stergiopoulos

Theoretically the auscultatory method using Korotkoff sounds is more related to the maximum artery closure status, while the oscillometric method is more related to the overall artery closure status under the cuff. Therefore, the latter is less accurate th ...

Elsevier2013

Effects of Isoflurane Anesthesia on Aortic Compliance and Systemic Hemodynamics in Compliant and Noncompliant Aortas

Nikolaos Stergiopoulos

Objectives: To investigate the effect of general anesthesia on aortic compliance and other cardiovascular hemodynamics in chronically instrumented pigs with compliant and noncompliant (stiff) aortas. Design: Experimental study. Setting: University animal l ...

W B Saunders Co-Elsevier Inc2013

Biomechanical analysis of cerebral arteries : role of elastin and its implication in aging and cerebrovascular disease

Edouard Fonck

The intent of this thesis is to study the function of elastin in cerebral arteries, its contribution into the aging process and its implication into different cerebral diseases and in particular cerebral aneurysms. As of today, little is known on the genes ...

EPFL2008

The effect of a myocardial infarction on the normalized time-varying elastance curve

Nikolaos Stergiopoulos, Rafaela Fernandes Da Silva, David Jegger

It has been suggested that the shape of the normalized time-varying elastance curve [E(n)(t(n))] is conserved in different cardiac pathologies. We hypothesize, however, that the E(n)(t(n)) differs quantitatively after myocardial infarction (MI). Sprague-Da ...

2006

Arterial pressure transfer characteristics: effects of travel time

Nikolaos Stergiopoulos, Nico Westerhof

We investigated the quantitative contribution of all local conduit arterial, blood, and distal load properties to the pressure transfer function from brachial artery to aorta. The model was based on anatomical data, Young's modulus, wall viscosity, blood v ...

2006

Noninvasive Doppler-derived myocardial performance index in rats with myocardial infarction: validation and correlation by conductance catheter

Nikolaos Stergiopoulos, David Jegger, Patrick Segers

The rodent model of myocardial infarction (MI) is extensively used in heart failure studies. However, long-term follow-up of echocardiographic left ventricular (LV) function parameters such as the myocardial performance index (MPI) and its ratio with the f ...

2005