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Michel R. Labrosse

Bio: Michel R. Labrosse is an academic researcher from University of Ottawa. The author has contributed to research in topics: Aortic valve & Aortic dissection. The author has an hindex of 22, co-authored 65 publications receiving 1767 citations. Previous affiliations of Michel R. Labrosse include Carolinas Medical Center & University of Akron.


Papers
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TL;DR: Different regions of the aneurysm have different yield stress, yield strains, and other mechanical properties, and this must be considered in understanding where the rupture might occur.
Abstract: There is a need to understand why and where the abdominal aortic aneurysm may rupture. Our goal therefore is to investigate whether the mechanical properties are different in different regions of t...

194 citations

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TL;DR: Both aortic root displacement and hypertension significantly increase the longitudinal stress in the ascending aorta, which may cause patients with hypertension who are at risk of dissection to be monitored as an important risk factor.
Abstract: Background— The downward movement of the aortic root during the cardiac cycle may be responsible for producing the circumferential tear observed in aortic dissections. Methods and Results— Contrast injections were investigated in 40 cardiac patients, and a finite element model of the aortic root, arch, and branches of the arch was built to assess the influence of aortic root displacement and pressure on the aortic wall stress. The axial displacement of the aortic root ranged from 0 to 14 mm. It was increased in patients with aortic insufficiency (22±13% of the sino-tubular junction diameter versus 12±9%) and reduced in patients with hypokinesis of the left ventricle (10±9% of sino-tubular junction versus 17±12%). The largest stress increase due to aortic root displacement was found approximately 2 cm above the sino-tubular junction, where the longitudinal stress increased by 50% to 0.32 Nmm−2 when 8.9-mm axial displacement was applied in addition to 120-mm Hg luminal pressure. A similar result was observe...

183 citations

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TL;DR: In this article, a finite element model of a simple straight wire rope strand is presented, which allows for the study of all possible interwire motions, and the role of the contact conditions in pure axial loading and in axial and bending combined with bending is investigated.

144 citations

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TL;DR: In this article, a comprehensive review of articles about rotating composite beams and blades is presented, which addresses analytical, semi-analytical and numerical studies dealing with dynamical problems involving adaptive/smart/intelligent materials (e.g., piezoelectric materials, electrorheological fluids, shape memory alloys, etc.), damping and vibration control, advanced composite materials, complicating effects and loadings, and experimental methods.
Abstract: Rotating composite beams and blades have a wide range of applications in various engineering structures such as wind turbines, industrial fans, and steam turbines. Therefore, proper understanding of such structures is of a great importance. As a result, the behavior of rotating composite beam structures has received a lot of attention. This paper presents a comprehensive review of scholarly articles about rotating composite beams as published in the past decades. The review addresses analytical, semi-analytical and numerical studies dealing with dynamical problems involving adaptive/smart/intelligent materials (e.g. piezoelectric materials, electrorheological fluids, shape memory alloys, etc.), damping and vibration control, advanced composite materials (e.g. functionally graded materials and nanocomposites), complicating effects and loadings (e.g. added mass, tapered beams, initial curve and twist, etc.), and experimental methods. Moreover, the influence of Vlasov or restrained warping, out-of-plane warping, transverse shear, arbitrary cross-sectional geometry, trapeze phenomena, swept tip, size-dependent effect, as well as other areas that have been considered in research, are reviewed in depth. The review concludes with a presentation of the remaining challenges and future research needs.

136 citations

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TL;DR: The geometry-based model presented here allows determining quickly if a certain set of valve component dimensions results in a functional valve, of great interest to designers of new prosthetic heart valve models, as well as to surgeons involved in valve-sparing surgery.

122 citations


Cited by
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TL;DR: In this paper, the use of diagnostic procedures and therapies introduced and tested for detection, management, or prevention of disease is discussed. But, the focus is on the medical profession.
Abstract: It is important that the medical profession play a central role in critically evaluating the use of diagnostic procedures and therapies introduced and tested for detection, management, or prevention of disease. Rigorous, expert analysis of the available data documenting absolute and relative

1,917 citations

Journal ArticleDOI
TL;DR: In this article, the use of diagnostic procedures and therapies introduced and tested for detection, management, or prevention of disease is discussed. But, the focus is on the medical profession.

1,083 citations

Journal ArticleDOI
TL;DR: The majority of patients with acute type A acute aortic dissection present with aorti diameters <5.5 cm and thus do not fall within current guidelines for elective aneurysm surgery, and methods other than size measurement of the ascending aorta are needed to identify patients at risk for dissection.
Abstract: Background— Studies of aortic aneurysm patients have shown that the risk of rupture increases with aortic size. However, few studies of acute aortic dissection patients and aortic size exist. We used data from our registry of acute aortic dissection patients to better understand the relationship between aortic diameter and type A dissection. Methods and Results— We examined 591 type A dissection patients enrolled in the International Registry of Acute Aortic Dissection between 1996 and 2005 (mean age, 60.8 years). Maximum aortic diameters averaged 5.3 cm; 349 (59%) patients had aortic diameters <5.5 cm and 229 (40%) patients had aortic diameters <5.0 cm. Independent predictors of dissection at smaller diameters (<5.5 cm) included a history of hypertension (odds ratio, 2.17; 95% confidence interval, 1.03 to 4.57; P=0.04), radiating pain (odds ratio, 2.08; 95% confidence interval, 1.08 to 4.0; P=0.03), and increasing age (odds ratio, 1.03; 95% confidence interval, 1.00 to 1.05; P=0.03). Marfan syndrome pati...

655 citations

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TL;DR: The anatomy of the trifoliate aortic valvar complex is described and its implications for percutaneous valvar replacement are described.
Abstract: The books and articles devoted to the anatomy of the aortic valvar complex are numerous. Until now, however, little consideration has been given to understanding the anatomy with percutaneous valvar replacement in mind. It is axiomatic that knowledge of the anatomy of the valve is fundamental in understanding key principles involved in valvar replacement. Such an appreciation of the anatomy helps better understand the optimal positioning for the prosthetic valve within the root of the aorta with respect to the coronary arteries, mitral valve, and the conduction system and may circumvent complications that can arise during its implantation. In this review, therefore, we describe the anatomy of the trifoliate aortic valvar complex and its implications for percutaneous valvar replacement.

598 citations

Journal ArticleDOI
TL;DR: Medical imaging systems: Physical principles and image reconstruction algorithms for magnetic resonance tomography, ultrasound and computer tomography (CT), and applications: Image enhancement, image registration, functional magnetic resonance imaging (fMRI).

536 citations