نتایج جستجو برای: heart valves

تعداد نتایج: 396404  

Journal: :Biomechanics and modeling in mechanobiology 2010
Eli J Weinberg Danial Shahmirzadi Mohammad Reza Kaazempur Mofrad

Theoretical models of the human heart valves are useful tools for understanding and characterizing the dynamics of healthy and diseased valves. Enabled by advances in numerical modeling and in a range of disciplines within experimental biomechanics, recent models of the heart valves have become increasingly comprehensive and accurate. In this paper, we first review the fundamentals of native he...

2017
Feng Xiao Rui Zheng Di Yang Kejiang Cao Shijiang Zhang Bingruo Wu Yongfeng Shao Bin Zhou

BACKGROUND Rheumatic heart disease is an autoimmune disease caused by group A streptococci infection and frequently affects the aortic valve. Sex differences are common in the disease progression, treatment, and outcome. However, little is known about the sex differences in the pathology of aortic valves in rheumatic heart disease. DESIGN We studied the end-stage calcific aortic valves from m...

Journal: :Journal of biomechanical engineering 2003
Peter Johansen Keefe B Manning John M Tarbell Arnold A Fontaine Steven Deutsch Hans Nygaard

Evaluation of cavitation in vivo is often based on recordings of high-pass filtered random high-frequency pressure fluctuations. We hypothesized that cavitation signal components are more appropriately assessed by a new method for extraction of random signal components of the pressure signals. We investigated three different valve types and found a high correlation between the two methods (r2: ...

2015
Victoria C. Garside Rebecca Cullum Olivia Alder Daphne Y. Lu Ryan Vander Werff Mikhail Bilenky Yongjun Zhao Steven J. M. Jones Marco A. Marra T. Michael Underhill Pamela A. Hoodless

Heart valve formation initiates when endothelial cells of the heart transform into mesenchyme and populate the cardiac cushions. The transcription factor SOX9 is highly expressed in the cardiac cushion mesenchyme, and is essential for heart valve development. Loss of Sox9 in mouse cardiac cushion mesenchyme alters cell proliferation, embryonic survival, and valve formation. Despite this importa...

2011
G. H. Thomas J. V. Candy D. Perkins R. D. Huber

Prosthetic heart valves are a blessing for people with defective heart valves. One type of mechanical heart valve that was manufactured between 1979 and 1985 has been implanted in approximately 86,000 people. Between 500 and 600 of these valves are known to have failed. The failure occurs when a thin wire strut breaks free, see Figure l. The strut has two legs that are attached to the main body...

2009
HA Mohamed

Patients with mechanical valve prostheses require a lifelong anticoagulant treatment. The combined use of Warfarin and low-dose aspirin appears to reduce the risk of valve thrombosis and systemic embolism at a low risk of bleeding. The management of women with prosthetic heart valves during pregnancy poses a particular challenge, as there are no available controlled clinical trials to provide g...

Journal: :British heart journal 1987
C Mortera M Rissech M Payola C Miro R Perich

A short axis echocardiographic cut of the heart from the subcostal approach was used to study the atrioventricular junction in 47 infants and children with congenital heart disease and 20 with normal hearts. Examination of the diastolic openings of both atrioventricular valves was able to establish normal developments of the valves and annuli even when this was found in cases of complex congeni...

Journal: :Artificial organs 2005
Wei Yin Siobhain Gallocher Leonard Pinchuk Richard T Schoephoerster Jolyon Jesty Danny Bluestein

Polymer heart valves have been under investigation since the 1960s, but their success has been hampered by an overall lack of durability mainly due to calcification of the leaflets and a relatively high rate of thromboembolic complications. A new polymer (Quatromer) trileaflet design was tested for its thrombogenic potential and was compared to that of existing prosthetic heart valves routinely...

Journal: :Circulation 2006
Anita Mol Marcel C M Rutten Niels J B Driessen Carlijn V C Bouten Gregor Zünd Frank P T Baaijens Simon P Hoerstrup

BACKGROUND Tissue engineering represents a promising approach for the development of living heart valve replacements. In vivo animal studies of tissue-engineered autologous heart valves have focused on pulmonary valve replacements, leaving the challenge to tissue engineer heart valves suitable for systemic application using human cells. METHODS AND RESULTS Tissue-engineered human heart valves...

Journal: :The Journal of heart valve disease 2004
Andrew J Hodge William M L Neethling Ross Glancy

BACKGROUND AND AIM OF THE STUDY The performance and longevity of bioprosthetic heart valves are limited by tissue calcification and degeneration after implantation. Experimental valve replacement in large animal models forms an important component of the preclinical evaluation of these bioprosthetic heart valves. The study aim was to assess the feasibility of a mitral model for stentless valves...

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