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Mechanical Valve

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https://www.readbyqxmd.com/read/28942968/survival-and-long-term-outcomes-after-mitral-valve-replacement-in-patients-aged-18-to-50%C3%A2-years
#1
Samuel R Schnittman, Shinobu Itagaki, Nana Toyoda, David H Adams, Natalia N Egorova, Joanna Chikwe
OBJECTIVE: To provide long-term data on survival and major morbidity after mitral valve replacement in patients aged 18 to 50 years. METHODS: Retrospective analysis of 2727 patients aged 18 to 50 years who underwent isolated mitral replacement in California and New York from 1997 to 2006. Median follow-up time was 12.4 years (maximum 15.0 years). The primary endpoint was mortality; secondary endopoints were stroke, major bleeding, and reoperation. Propensity matching yielded 373 patient pairs...
August 24, 2017: Journal of Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28942609/custom-extracellular-matrix-cylinder-mitral-valve-in-a-pediatric-patient
#2
Clifford L Cua, Pace Johnston, Jill Harmon, Kathryn Shelton, Patrick I McConnell
Mitral valve construction using extracellular matrix (ECM) is a relatively new procedure. In this case, a 15-month-old boy with a history of severe mitral valve regurgitation secondary to endocarditis underwent mitral valve surgery. Mitral valve repair was not possible, and thus, a 17 mm extracellular matrix cylinder valve (ECM-CV) was constructed for valve replacement. The ECM-CV is clearly imaged using echocardiography, especially three-dimensional imaging, that helped define valve function. As the use of ECM for valve construction increases, echocardiography will play an essential role in evaluating the function and mechanics of these novel valves...
September 24, 2017: Echocardiography
https://www.readbyqxmd.com/read/28941606/new-developments-in-hypertrophic-cardiomyopathy
#3
REVIEW
Robert M Cooper, Claire E Raphael, Max Liebregts, Nandan S Anavekar, Josef Veselka
Hypertrophic cardiomyopathy is the leading cause of sudden death in young individuals and an important cause of heart failure at any age. In this review we discuss advances in investigation and management of this heterogenous disease. Improved cardiac imaging has allowed us to detail many of the structural abnormalities whereas the use of new techniques, predominantly in cardiac magnetic resonance imaging, has given us a greater insight in to tissue architecture, mechanism of contractile abnormalities, and function...
October 2017: Canadian Journal of Cardiology
https://www.readbyqxmd.com/read/28940406/congenital-aortic-valve-repair-using-cormatrix-%C3%A2-a-histologic-evaluation
#4
Michael Hofmann, Martin O Schmiady, Barbara E Burkhardt, Hitendu H Dave, Michael Hübler, Oliver Kretschmar, Peter K Bode
BACKGROUND: The reconstruction of heart valves provides substantial benefits, particularly in the pediatric population. We present our experience using decellularized extracellular matrix (dECM, CorMatrix(®) ) for aortic valve procedures. METHODS: We retrospectively reviewed the case histories of 6 patients (aged from 2 months - 14 years) who underwent surgery for severe aortic valve stenosis (n = 4) or regurgitation (n = 2). Aortic valve repair was performed on all patients using dECM as a leaflet replacement or leaflet extension...
September 22, 2017: Xenotransplantation
https://www.readbyqxmd.com/read/28939354/a-deep-learning-approach-to-estimate-chemically-treated-collagenous-tissue-nonlinear-anisotropic-stress-strain-responses-from-microscopy-images
#5
Liang Liang, Minliang Liu, Wei Sun
Biological collagenous tissues comprised of networks of collagen fibers are suitable for a broad spectrum of medical applications owing to their attractive mechanical properties. In this study, we developed a noninvasive approach to estimate collagenous tissue elastic properties directly from microscopy images using Machine Learning (ML) techniques. Glutaraldehyde-treated bovine pericardium (GLBP) tissue, widely used in the fabrication of bioprosthetic heart valves and vascular patches, was chosen to develop a representative application...
September 19, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28935890/demonstration-and-analysis-of-the-suction-effect-for-pumping-lymph-from-tissue-beds-at-subatmospheric-pressure
#6
Samira Jamalian, Mohammad Jafarnejad, Scott D Zawieja, Christopher D Bertram, Anatoliy A Gashev, David C Zawieja, Michael J Davis, James E Moore
Many tissues exhibit subatmospheric interstitial pressures under normal physiologic conditions. The mechanisms by which the lymphatic system extracts fluid from these tissues against the overall pressure gradient are unknown. We address this important physiologic issue by combining experimental measurements of contractile function and pressure generation with a previously validated mathematical model. We provide definitive evidence for the existence of 'suction pressure' in collecting lymphatic vessels, which manifests as a transient drop in pressure downstream of the inlet valve following contraction...
September 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28932355/is-there-evidence-for-statins-in-the-treatment-of-aortic-valve-stenosis
#7
REVIEW
Ibrahim Akin, Christoph A Nienaber
Research revealed that the pathogenesis of aortic stenosis (AS) not merely comprises of a mechanical wear and tear process yet that active biological processes, similar to those of coronary artery disease are involved, a promising role for statins in disease-modifying therapy was suggested. However, recently, many prospective studies could not observe decreased progression nor regression of the disease. Here, we review the current knowledge on the pathomechanisms of AS and its similarities and differences with atherosclerosis...
August 26, 2017: World Journal of Cardiology
https://www.readbyqxmd.com/read/28929446/new-imaging-tools-in-cardiovascular-medicine-computational-fluid-dynamics-and-4d-flow-mri
#8
Keiichi Itatani, Shohei Miyazaki, Tokoki Furusawa, Satoshi Numata, Sachiko Yamazaki, Kazuki Morimoto, Rina Makino, Hiroko Morichi, Teruyasu Nishino, Hitoshi Yaku
Blood flow imaging is a novel technology in cardiovascular medicine and surgery. Today, two types of blood flow imaging tools are available: measurement-based flow visualization including 4D flow MRI (or 3D cine phase-contrast magnetic resonance imaging), or echocardiography flow visualization software, and computer flow simulation modeling based on computational fluid dynamics (CFD). MRI and echocardiography flow visualization provide measured blood flow but have limitations in temporal and spatial resolution, whereas CFD flow calculates the flow according to assumptions instead of flow measurement, and it has sufficiently fine resolution up to the computer memory limit, and it enables even virtual surgery when combined with computer graphics...
September 19, 2017: General Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28927733/retrospective-study-of-anaesthetic-management-of-pregnant-patients-with-mechanical-heart-valve-prosthesis-and-anticoagulants
#9
Benoît Cousin, Jean Guglielminotti, Bernard Iung, Philippe Montravers
No abstract text is available yet for this article.
September 16, 2017: Anaesthesia, Critical Care & Pain Medicine
https://www.readbyqxmd.com/read/28921000/-hemodynamic-interplay-between-tricuspid-valve-and-right-ventricle
#10
REVIEW
C Edel, R Erbel, T Budde
The tricuspid valve and the right ventricle are hemodynamically closely related. Pathological changes of the valve or of the ventricle itself and also various diseases beyond that can result in a downward spiral of mutual interference, which is of prognostic importance for the patient. The development of a functional tricuspid regurgitation is of great importance. Especially with the help of 3D-echocardiography, more and more changes and mechanisms have been identified that are crucial in this process. This article provides a review of the relationship between the tricuspid valve and the right ventricle emphasizing the current knowledge of the causes, the pathophysiological concepts, the underlying structural changes and the therapeutic approaches based on this...
September 18, 2017: Herz
https://www.readbyqxmd.com/read/28919940/calcitox-aging-counterbalanced-by-endogenous-farnesol-like-sesquiterpenoids-an-undervalued-evolutionarily-ancient-key-signaling-pathway
#11
Arnold De Loof
Cells are powerful miniature electrophoresis chambers, at least during part of their life cycle. They die at the moment the voltage gradient over their plasma membrane, and their ability to drive a self-generated electric current carried by inorganic ions through themselves irreversibly collapses. Senescence is likely due to the progressive, multifactorial damage to the cell's electrical system. This is the essence of the "Fading electricity theory of aging" (De Loof et al., Aging Res. Rev. 2013;12:58-66)...
2017: Communicative & Integrative Biology
https://www.readbyqxmd.com/read/28918896/role-of-circulating-endothelial-progenitor-cells-in-the-reparative-mechanisms-of-stable-ischemic-myocardium
#12
D Morrone, F Felice, C Scatena, A De Martino, M L E Picoi, N Mancini, S Blasi, M Menicagli, R Di Stefano, U Bortolotti, A G Naccarato, A Balbarini
BACKGROUND: Mobilization of endothelial progenitor cells (EPCs) into circulation from bone marrow in patients with acute myocardial infarction has strong scientific evidence; less is known about EPC mobilization in patients with stable coronary artery disease (CAD). The aim of this study was to investigate the association of stable ischemic heart disease with EPC levels in tissue and blood. METHODS: Fifty-five consecutive patients admitted to a single treatment center for valve or coronary artery bypass grafting (CABG) surgeries were included in the study...
September 14, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28915471/characterization-of-mechanical-properties-of-pericardium-tissue-using-planar-biaxial-tension-and-flexural-deformation
#13
Kyle Murdock, Caitlin Martin, Wei Sun
Flexure is an important mode of deformation for native and bioprosthetic heart valves. However, mechanical characterization of bioprosthetic leaflet materials has been done primarily through planar tensile testing. In this study, an integrated experimental and computational cantilever beam bending test was performed to characterize the flexural properties of glutaraldehyde-treated bovine and porcine pericardium of different thicknesses. A strain-invariant based structural constitutive model was used to model the pericardial mechanical behavior quantified through the bending tests of this study and the planar biaxial tests previously performed...
September 12, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28914661/percutaneous-aortic-leak-closure-in-a-small-and-frail-annulus-after-double-heart-valve-replacement
#14
Guglielmo Saitto, Paolo Nardi, Gian P Ussia, Domenico Sergi, Paolo Prati, Marco Russo, Francesco Romeo, Giovanni Ruvolo
: Paravalvular leak (PVL) is an uncommon but serious complication associated with the implantation of prosthetic valves. Following aortic valve replacement, up to 5% of patients affected by PVL develop clinical symptoms of heart failure, hemolysis or both. Percutaneous treatment of PVL has emerged instead of conventional surgery, as a well tolerated and less invasive procedure but remains a challenge. We present the case of a young woman with mechanical aortic and mitral prostheses, who presented surgical aortic PVL caused by a serious frailty of native annulus, became symptomatic after 5 months and was successfully percutaneously treated with an Amplatzer Duct Occluder device...
September 12, 2017: Journal of Cardiovascular Medicine
https://www.readbyqxmd.com/read/28914415/a-randomized-trial-of-restarting-warfarin-at-maintenance-versus-loading-doses-following-an-elective-procedure
#15
Tammy J Bungard, Jay Mutch, Bruce Ritchie
Guidelines suggest restarting warfarin at known maintenance doses, although this may result in a delay to achieving therapeutic anticoagulation. As such, we compared the time to achieve an INR ≥ 2.0 between those restarting warfarin maintenance vs loading doses after transient interruption, and the impact on protein C, S and factor II levels. Patients requiring interruption of warfarin for elective procedures without hospitalization were randomized 1:1 to receive warfarin maintenance or loading doses (1...
September 15, 2017: Journal of Thrombosis and Thrombolysis
https://www.readbyqxmd.com/read/28914311/comparing-caenorhabditis-elegans-gentle-and-harsh-touch-response-behavior-using-a-multiplexed-hydraulic-microfluidic-device
#16
Patrick D McClanahan, Joyce H Xu, Christopher Fang-Yen
The roundworm Caenorhabditis elegans is an important model system for understanding the genetics and physiology of touch. Classical assays for C. elegans touch, which involve manually touching the animal with a probe and observing its response, are limited by their low throughput and qualitative nature. We developed a microfluidic device in which several dozen animals are subject to spatially localized mechanical stimuli with variable amplitude. The device contains 64 sinusoidal channels through which worms crawl, and hydraulic valves that deliver touch stimuli to the worms...
September 15, 2017: Integrative Biology: Quantitative Biosciences From Nano to Macro
https://www.readbyqxmd.com/read/28913590/challenges-of-anticoagulation-therapy-in-pregnancy
#17
REVIEW
Annemarie E Fogerty
Thrombotic complications in pregnancy represent a major cause of morbidity and mortality. Pregnancy is a primary hypercoagulable state due to enhanced production of clotting factors, a decrease in protein S activity, and inhibition of fibrinolysis. These physiologic changes will yield a collective rate of venous thromboembolism (VTE) of about 1-2 in 1000 pregnancies for the general obstetric population, which represents a five- to tenfold increased risk in pregnancy compared to age-matched non-pregnant peers...
September 14, 2017: Current Treatment Options in Cardiovascular Medicine
https://www.readbyqxmd.com/read/28913289/communicating-hydrocephalus-onset-following-a-traumatic-tension-pneumocephalus
#18
Jin-Sung Lee, Sora Ahn, Ki Seong Eom
The entrapment of intracranial air from the check valve system results in a tension pneumocephalus. It should be distinguished from simple pneumocephalus because they are intracranial space-occupying masses that can threaten life. Communicating hydrocephalus is a serious and frequent complication of post-traumatic head injury. Head injury is one of the most common causes in etiopathogenesis of communicating hydrocephalus. Here, we describe a case of a 65-year-old man who developed communicating hydrocephalus after a post-traumatic tension pneumocephalus...
December 2016: Arch Craniofac Surg
https://www.readbyqxmd.com/read/28912876/effect-of-intercostal-nerve-block-combined-with-general-anesthesia-on-the-stress-response-in-patients-undergoing-minimally-invasive-mitral-valve-surgery
#19
Yanping Zhan, Guo Chen, Jian Huang, Benchao Hou, Weicheng Liu, Shibiao Chen
The aim of the present study was to investigate the effect of intercostal nerve block combined with general anesthesia on the stress response and postoperative recovery in patients undergoing minimally invasive mitral valve surgery (MIMVS). A total of 30 patients scheduled for MIMVS were randomly divided into two groups (n=15 each): Group A, which received intercostal nerve block combined with general anesthesia and group B, which received general anesthesia alone. Intercostal nerve block in group A was performed with 0...
October 2017: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/28912416/a-case-of-tranexamic-acid-as-adjunctive-treatment-for-chronic-subdural-hematoma-with-multiple-recurrences
#20
Ronni Mikkelsen, Thorkil Anker-Møller, Anne-Mette Hvas, Niels Sunde
BACKGROUND Chronic subdural hematoma (CSDH) is a common neurosurgical condition that is treated using a cranial burr hole evacuation procedure, but recurrence is common. The use of anticoagulant therapy can increase the risk of developing a recurrent subdural hematoma. We present a challenging case of a patient on long-term anticoagulant therapy following previous aortic and aortic valve surgery who had CSDH with multiple recurrences and was ultimately treated with tranexamic acid as an adjunct to surgery. CASE REPORT A male patient in his mid-sixties presented with a headache and bilateral CSDH...
September 15, 2017: American Journal of Case Reports
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