Publications by Bram Trachet | EPFL Graph Search

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

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

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

Early Morphofunctional Changes in AngII-Infused Mice Contribute to Regional Onset of Aortic Aneurysm and Dissection

Nikolaos Stergiopoulos, Bram Trachet, Lydia Aslanidou, Goran Lovric

Aortic aneurysms and dissections are silent and lethal conditions, whose pathogenesis remains incompletely understood. Although angiotensin II (AngII)-infused ApoE-/- mice have been widely used to study aortic aneurysm and dissection, early morphofunctiona ...

KARGER2020

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

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

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

Co-localization of microstructural damage and excessive mechanical strain at aortic branches in Angiotensin-II-infused mice

Nikolaos Stergiopoulos, Patrick Segers, Bram Trachet, Lydia Aslanidou, Mauro Ferraro, Goran Lovric

Animal models of aortic aneurysm and dissection can enhance our limited understanding of the etiology of these lethal conditions particularly because early-stage longitudinal data are scant in humans. Yet, the pathogenesis of often-studied mouse models and ...

2019

Synchrotron-based visualization and segmentation of elastic lamellae in the mouse carotid artery during quasi-static pressure inflation

Nikolaos Stergiopoulos, Patrick Segers, Bram Trachet, Lydia Aslanidou, Mauro Ferraro, Goran Lovric

2019

Synchrotron-based phase contrast imaging of cardiovascular tissue in mice-grating interferometry or phase propagation?

Nikolaos Stergiopoulos, Patrick Segers, Bram Trachet, Lydia Aslanidou, Mauro Ferraro, Goran Lovric

Synchrotron-based x-ray phase-contrast imaging allows for detailed 3D insight into the microstructure of soft tissue and is increasingly used to improve our understanding of mouse models of cardiovascular disease. Two techniques dominate the field: grating ...

2019

On the importance of the nonuniform aortic stiffening in the hemodynamics of physiological aging

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

Mathematical models of the arterial tree constitute a valuable tool to investigate the hemodynamics of aging and pathology. Rendering such models as patient specific could allow for the assessment of central hemodynamic variables of clinical interest. Howe ...

AMER PHYSIOLOGICAL SOC2019

Propagation-based phase-contrast synchrotron imaging of aortic dissection in mice: from individual elastic lamella to 3D analysis

Nikolaos Stergiopoulos, Patrick Segers, Bram Trachet, Lydia Aslanidou, Marco Stampanoni

In order to show the advantage and potential of propagation-based phase-contrast synchrotron imaging in vascular pathology research, we analyzed aortic medial ruptures in BAPN/AngII-infused mice, a mouse model for aortic dissection. Ascending and thoraco-a ...

Nature Research2018

Should We Ignore What We Cannot Measure? How Non-Uniform Stretch, Non-Uniform Wall Thickness and Minor Side Branches Affect Computational Aortic Biomechanics in Mice

Nikolaos Stergiopoulos, Patrick Segers, Bram Trachet, Lydia Aslanidou, Mauro Ferraro, Heleen Christine Greet Fehervary

2018

Angiotensin II infusion into ApoE(-/-) mice: a model for aortic dissection rather than abdominal aortic aneurysm?

Nikolaos Stergiopoulos, Patrick Segers, Jessica Sordet, Alessandra Piersigilli, Bram Trachet, Lydia Aslanidou

Aims Angiotensin II-infused ApoE(-/-) mice are a popular mouse model for preclinical aneurysm research. Here, we provide insight in the often-reported but seldom-explained variability in shape of dissecting aneurysms in these mice. Methods and results N=45 ...

2017

The influence of anesthesia and fluid-structure interaction on simulated shear stress patterns in the carotid bifurcation of mice

Patrick Segers, Bram Trachet

Background: Low and oscillatory wall shear stresses (WSS) near aortic bifurcations have been linked to the onset of atherosclerosis. In previous work, we calculated detailed WSS patterns in the carotid bifurcation of mice using a Fluid-structure interactio ...

Elsevier Sci Ltd2016

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

Patrick Segers, Bram Trachet

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

A 1D model of the arterial circulation in mice

Nikolaos Stergiopoulos, Philippe Reymond, Patrick Segers, Bram Trachet, Lydia Aslanidou

At a time of growing concern over the ethics of animal experimentation, mouse models are still an indispensable source of insight into the cardiovascular system and its most frequent pathologies. Nevertheless, reference data on the murine cardiovascular an ...

2016

Pitfalls Of Doppler Measurements For Arterial Blood Flow Quantification In Small Animal Research: A Study Based On Virtual Ultrasound Imaging

Patrick Segers, Bram Trachet

High-resolution Doppler is a popular tool for evaluating cardiovascular physiology in mutant mice, though its 1-D nature and spectral broadening processes complicate interpretation of the measurement. Hence, it is crucial for pre-clinical researchers to kn ...

Elsevier2016

Shear Stress Metrics and Their Relation to Atherosclerosis: An In Vivo Follow-up Study in Atherosclerotic Mice

Patrick Segers, Bram Trachet

It is generally accepted that low and oscillatory wall shear stress favors the initiation and development of atherosclerosis. However, a quantitative analysis of the association between shear stress metrics at baseline and lesion prevalence at a later stag ...

Springer Verlag2016

Ascending Aortic Aneurysm in Angiotensin II–Infused Mice: Formation, Progression, and the Role of Focal Dissections

Nikolaos Stergiopoulos, Patrick Segers, Jessica Sordet, Alessandra Piersigilli, Bram Trachet, Lydia Aslanidou

Objective To understand the anatomy and physiology of ascending aortic aneurysms in angiotensin II-infused ApoE(-/-) mice. Approach and Results We combined an extensive in vivo imaging protocol (high-frequency ultrasound and contrast-enhanced microcomputed ...

2016

Performance Comparison of Ultrasound-Based Methods to Assess Aortic Diameter and Stiffness in Normal and Aneurysmal Mice

Nikolaos Stergiopoulos, Patrick Segers, Bram Trachet

Objective Several ultrasound-based methods are currently used to assess aortic diameter, circumferential strain and stiffness in mice, but none of them is flawless and a gold standard is lacking. We aimed to assess the validity and sensitivity of these met ...

Public Library Science2015

Dissecting Abdominal Aortic Aneurysm in Angiotensin II-Infused Mice: The Importance of Imaging

Nikolaos Stergiopoulos, Patrick Segers, Alessandra Piersigilli, Bram Trachet

Introduction. Since the initial publication in 2000, Angiotensin II-infused mice have become one of the most popular models to study abdominal aortic aneurysm in a pre-clinical setting. We recently used phase contrast X-ray based computed tomography to dem ...

2015

Novel Insights on Aortic Aneurysm

Bram Trachet

Bentham Science Publishers2015

Emerging Pharmacological Treatments to Prevent Abdominal Aortic Aneurysm Growth and Rupture

Nikolaos Stergiopoulos, Bram Trachet

Abdominal aortic aneurysm (AAA) is a local expansion of the abdominal aorta wall caused by a complex multifactorial maladaptive vascular remodeling. Despite recent advances in the management of cardiovascular diseases, there currently is no established dru ...

Bentham Science Publ Ltd2015