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Sample records for disc mechanical mitral

  1. Mitral disc-valve variance

    PubMed Central

    Berroya, Renato B.; Escano, Fernando B.

    1972-01-01

    This report deals with a rare complication of disc-valve prosthesis in the mitral area. A significant disc poppet and struts destruction of mitral Beall valve prostheses occurred 20 and 17 months after implantation. The resulting valve incompetence in the first case contributed to the death of the patient. The durability of Teflon prosthetic valves appears to be in question and this type of valve probably will be unacceptable if there is an increasing number of disc-valve variance in the future. Images PMID:5017573

  2. DISC VARIANCE OF THE HARKEN MITRAL PROSTHESIS: THE CONTRIBUTION OF ASSOCIATED AORTIC REGURGITATION

    PubMed Central

    Yarnoz, Michael D.; Hueter, David; McCormick, John R.; Black, Harrison; Berger, Robert L.

    1977-01-01

    Four cases of severe mitral regurgitation due to disc variance of the Harken disc prosthesis in the mitral position are described. The valve occluder actually escaped into the left atrium in two patients, and neither survived despite emergency valve replacement. In the other two, disc malfunction was identified by flouroscopy, the prosthesis was replaced, and both patients survived. All four patients had associated aortic regurgitation, which most likely contributed to erosion of the disc edges. It is suggested that patients with the Harken disc prosthesis undergo periodic evaluation to detect abnormal disc motion. Images PMID:15216088

  3. Disc erosion in Models 103 and 104 of Beall mitral valve prostheses

    PubMed Central

    Gómez, Ricardo; Verduras, María José; Lopez-Quintana, Alfonso; Riera, Luis; Zerolo, Ignacio; Martinez-Bordiu, Cristóbal

    1981-01-01

    Three cases of severe disc variance and erosion of the Teflon-disc Beall mitral valve prosthesis (Models 103 and 104) are reported. In two patients, the Beall mitral valves were excised and replaced with two Björk-Shiley mitral valves. The remaining patient did not survive, and at autopsy, the lens was found at the aortic bifurcation level. Because of this potentially lethal complication, careful follow-up of patients with Beall mitral valve prostheses (Models 103 and 104) is recommended. Images PMID:15216211

  4. Mitral valve disease—morphology and mechanisms

    PubMed Central

    Levine, Robert A.; Hagége, Albert A.; Judge, Daniel P.; Padala, Muralidhar; Dal-Bianco, Jacob P.; Aikawa, Elena; Beaudoin, Jonathan; Bischoff, Joyce; Bouatia-Naji, Nabila; Bruneval, Patrick; Butcher, Jonathan T.; Carpentier, Alain; Chaput, Miguel; Chester, Adrian H.; Clusel, Catherine; Delling, Francesca N.; Dietz, Harry C.; Dina, Christian; Durst, Ronen; Fernandez-Friera, Leticia; Handschumacher, Mark D.; Jensen, Morten O.; Jeunemaitre, Xavier P.; Le Marec, Hervé; Le Tourneau, Thierry; Markwald, Roger R.; Mérot, Jean; Messas, Emmanuel; Milan, David P.; Neri, Tui; Norris, Russell A.; Peal, David; Perrocheau, Maelle; Probst, Vincent; Pucéat, Michael; Rosenthal, Nadia; Solis, Jorge; Schott, Jean-Jacques; Schwammenthal, Ehud; Slaugenhaupt, Susan A.; Song, Jae-Kwan; Yacoub, Magdi H.

    2016-01-01

    Mitral valve disease is a frequent cause of heart failure and death. Emerging evidence indicates that the mitral valve is not a passive structure, but—even in adult life—remains dynamic and accessible for treatment. This concept motivates efforts to reduce the clinical progression of mitral valve disease through early detection and modification of underlying mechanisms. Discoveries of genetic mutations causing mitral valve elongation and prolapse have revealed that growth factor signalling and cell migration pathways are regulated by structural molecules in ways that can be modified to limit progression from developmental defects to valve degeneration with clinical complications. Mitral valve enlargement can determine left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and might be stimulated by potentially modifiable biological valvular–ventricular interactions. Mitral valve plasticity also allows adaptive growth in response to ventricular remodelling. However, adverse cellular and mechanobiological processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with increased heart failure and mortality. Our approach, which bridges clinicians and basic scientists, enables the correlation of observed disease with cellular and molecular mechanisms, leading to the discovery of new opportunities for improving the natural history of mitral valve disease. PMID:26483167

  5. Mitral valve disease--morphology and mechanisms.

    PubMed

    Levine, Robert A; Hagége, Albert A; Judge, Daniel P; Padala, Muralidhar; Dal-Bianco, Jacob P; Aikawa, Elena; Beaudoin, Jonathan; Bischoff, Joyce; Bouatia-Naji, Nabila; Bruneval, Patrick; Butcher, Jonathan T; Carpentier, Alain; Chaput, Miguel; Chester, Adrian H; Clusel, Catherine; Delling, Francesca N; Dietz, Harry C; Dina, Christian; Durst, Ronen; Fernandez-Friera, Leticia; Handschumacher, Mark D; Jensen, Morten O; Jeunemaitre, Xavier P; Le Marec, Hervé; Le Tourneau, Thierry; Markwald, Roger R; Mérot, Jean; Messas, Emmanuel; Milan, David P; Neri, Tui; Norris, Russell A; Peal, David; Perrocheau, Maelle; Probst, Vincent; Pucéat, Michael; Rosenthal, Nadia; Solis, Jorge; Schott, Jean-Jacques; Schwammenthal, Ehud; Slaugenhaupt, Susan A; Song, Jae-Kwan; Yacoub, Magdi H

    2015-12-01

    Mitral valve disease is a frequent cause of heart failure and death. Emerging evidence indicates that the mitral valve is not a passive structure, but--even in adult life--remains dynamic and accessible for treatment. This concept motivates efforts to reduce the clinical progression of mitral valve disease through early detection and modification of underlying mechanisms. Discoveries of genetic mutations causing mitral valve elongation and prolapse have revealed that growth factor signalling and cell migration pathways are regulated by structural molecules in ways that can be modified to limit progression from developmental defects to valve degeneration with clinical complications. Mitral valve enlargement can determine left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and might be stimulated by potentially modifiable biological valvular-ventricular interactions. Mitral valve plasticity also allows adaptive growth in response to ventricular remodelling. However, adverse cellular and mechanobiological processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with increased heart failure and mortality. Our approach, which bridges clinicians and basic scientists, enables the correlation of observed disease with cellular and molecular mechanisms, leading to the discovery of new opportunities for improving the natural history of mitral valve disease.

  6. Fracture and embolization of a Lillehei-Kaster mitral valve prosthesis disc: one case successfully operated.

    PubMed

    Pilichowski, P; Gaudin, P; Brichon, P Y; Neron, L; Wolf, J E; Machecourt, J; Latreille, R

    1987-12-01

    We report the fracture of the poppet of a Lillehei-Kaster prosthesis. A 40 years old man was operated upon for endocarditis of the mitral valve. A Lillehei-Kaster tilting disc valve was implanted. Three years later the disc fractured and the two parts escaped in the aorto-iliac axis. Emergency surgical procedure permitted implantation of a Wessex bioprosthesis and removal of the fragments with good results.

  7. Harken Caged-Disc Mitral Valve Replacement, 1969-1975: Analysis of Late Mortality, Thromboembolism, and Valve Failure

    PubMed Central

    Gray, Richard J.; Czer, Lawrence S.C.; Chaux, Aurelio; Sethna, Dhun; Derobertis, Michele; Raymond, Marjorie; Matloff, Jack M.

    1987-01-01

    We evaluated the long-term outcome of mitral valve replacement with a Harken caged-disc prosthesis for up to 11 years (range, 50 to 130 months; mean, 81 months) in 170 patients whose mean age was 55 years. The early (30-day) mortality was 11.2% (19 out of 170 patients). Late follow-up information was obtained for 144 (95%) of the 151 survivors. The actuarial survival was 57% at 5 years and 40% at 10 years. Overall mortality was associated with advanced age, male sex, an ischemic origin for the mitral valve disease, and nonuse of warfarin anticoagulation. Late deaths (n=59) were valve-related in 46%, cardiac but non-valve-related in 44%, and noncardiac in 10% of the cases. One thromboembolic event or more occurred in 41 patients (incidence, 5.7% per patient year), 14 of whom died (24% of the late deaths). All four patients who were not on warfarin, aspirin, or other antithrombotic therapy experienced thromboemboli. This complication was correlated with the nonuse of warfarin-type anticoagulation, with mitral regurgitation, and with late cardiac death. Mechanical prosthetic failure resulted in reoperation or death in 7.6% of the late survivors (1.5% per patient year). In 75 patients with normally functioning prostheses, the disc-to-sewing ring ratio was established by means of cinefluoroscopy (0.93 ± 0.04, mean ± 25D). Because of the high proportion of cardiac valve-related deaths (46%), the high incidence of late mortality due to thromboembolic events (24%), and the 7.6% incidence of reoperation or death resulting from mechanical valve failure, close follow-up with cinefluoroscopy and continued warfarin anticoagulation (alone or in combination with dipyridamole) are essential after mitral valve replacement with the Harken caged-disc prosthesis. (Texas Heart Institute Journal 1987; 14:411-417) Images PMID:15227298

  8. A note on the critical flow to initiate closure of pivoting disc mitral valve prostheses.

    PubMed

    Reif, T H; Huffstutler, M C

    1985-01-01

    Newton's second law of motion for rotating bodies and potential flow theory is used to mathematically model the closing process of a pivoting disc prosthetic heart valve in mitral position. The model predicts closure to be dependent upon disc curvature, eccentricity, mass, diameter, density, opening angle and fluid properties. Experiments using two commercially available prostheses are shown to give good correlation with the theory for large opening angles. Divergence between theory and experiment occur at small opening angles because of the limitation of the potential flow assumption.

  9. Mechanics of Actuated Disc Cutting

    NASA Astrophysics Data System (ADS)

    Dehkhoda, Sevda; Detournay, Emmanuel

    2017-02-01

    This paper investigates the mechanics of an actuated disc cutter with the objective of determining the average forces acting on the disc as a function of the parameters characterizing its motion. The specific problem considered is that of a disc cutter revolving off-centrically at constant angular velocity around a secondary axis rigidly attached to a cartridge, which is moving at constant velocity and undercutting rock at a constant depth. This model represents an idealization of a technology that has been implemented in a number of hard rock mechanical excavators with the goal of reducing the average thrust force to be provided by the excavation equipment. By assuming perfect conformance of the rock with the actuated disc as well as a prescribed motion of the disc (perfectly rigid machine), the evolution of the contact surface between the disc and the rock during one actuation of the disc can be computed. Coupled with simple cutter/rock interaction models that embody either a ductile or a brittle mode of fragmentation, these kinematical considerations lead to an estimate of the average force on the cartridge and of the partitioning of the energy imparted by the disc to the rock between the actuation mechanism of the disc and the translation of the cartridge on which the actuated disc is attached.

  10. Novel pathogenetic mechanisms and structural adaptations in ischemic mitral regurgitation.

    PubMed

    Silbiger, Jeffrey J

    2013-10-01

    Ischemic mitral regurgitation (MR) is a common complication of myocardial infarction thought to result from leaflet tethering caused by displacement of the papillary muscles that occurs as the left ventricle remodels. The author explores the possibility that left atrial remodeling may also play a role in the pathogenesis of ischemic MR, through a novel mechanism: atriogenic leaflet tethering. When ischemic MR is hemodynamically significant, the left ventricle compensates by dilating to preserve forward output using the Starling mechanism. Left ventricular dilatation, however, worsens MR by increasing the mitral valve regurgitant orifice, leading to a vicious cycle in which MR begets more MR. The author proposes that several structural adaptations play a role in reducing ischemic MR. In contrast to the compensatory effects of left ventricular enlargement, these may reduce, rather than increase, its severity. The suggested adaptations involve the mitral valve leaflets, the papillary muscles, the mitral annulus, and the left ventricular false tendons. This review describes the potential role each may play in reducing ischemic MR. Therapies that exploit these adaptations are also discussed.

  11. Haemodynamic improvement of older, previously replaced mechanical mitral valves by removal of the subvalvular pannus in redo cardiac surgery.

    PubMed

    Kim, Jong Hun; Kim, Tae Youn; Choi, Jong Bum; Kuh, Ja Hong

    2017-01-01

    Patients requiring redo cardiac surgery for diseased heart valves other than mitral valves may show increased pressure gradients and reduced valve areas of previously placed mechanical mitral valves due to subvalvular pannus formation. We treated four women who had mechanical mitral valves inserted greater than or equal to 20 years earlier and who presented with circular pannus that protruded into the lower margin of the valve ring but did not impede leaflet motion. Pannus removal improved the haemodynamic function of the mitral valve.

  12. Percutaneous implantation of CoreValve aortic prostheses in patients with a mechanical mitral valve.

    PubMed

    Bruschi, Giuseppe; De Marco, Federico; Oreglia, Jacopo; Colombo, Paola; Fratto, Pasquale; Lullo, Francesca; Paino, Roberto; Frigerio, Maria; Martinelli, Luigi; Klugmann, Silvio

    2009-11-01

    Concerns exist in the field of transcatheter aortic valve implantation regarding the treatment of patients with mechanical mitral valve for possible interference between the percutaneous aortic valve and the mechanical mitral prosthesis. We report our experience with percutaneous aortic valve implantation in 4 patients with severe aortic stenosis, previously operated on for mitral valve replacement with a mechanical prosthesis. All patients underwent uneventful percutaneous retrograde CoreValve implantation (CoreValve Inc, Irvine, CA). No deformation of the nitinol tubing of the prostheses (ie, neither distortion nor malfunction of the mechanical valve in the mitral position) occurred in any of the patients. All patients are alive and asymptomatic at a mean follow-up of 171 days.

  13. Comparison of dysfunction with mechanical and porcine mitral valve prostheses.

    PubMed

    Magilligan, D J; Oyama, C; Alam, M

    1985-09-01

    We reviewed the incidence of dysfunction of the Smeloff-Cutter mechanical prosthetic valve and the Hancock porcine prosthetic valve in the mitral position. The Smeloff-Cutter valve was implanted from 1966 to 1972; 107 patients were discharged from the hospital and were at risk for dysfunction. Follow-up averaged 10 +/- 0.7 years SD. The Hancock valve was implanted from 1971 through 1984; 473 patients were at risk and follow-up averaged 4.7 +/- 3.4 years SD. Dysfunction of the Smeloff-Cutter valve occurred as thrombosis with incomplete poppet opening in 13 patients. Dysfunction of the Hancock valve occurred as primary tissue failure in 47 patients. At 10 years the freedom from dysfunction of the Smeloff-Cutter valve was 84 +/- 5% SE and that for the Hancock valve was 71 +/- 4% SE (p greater than .06). The mortality associated with dysfunction of the Smeloff-Cutter valve was 46%; mortality associated with dysfunction of the Hancock valve was 15% (p less than .02). At 10 years the Hancock valve had a greater incidence of dysfunction than the Smeloff-Cutter valve but this difference was not statistically significant. The mortality associated with dysfunction of the Smeloff-Cutter valve, however, was three times that associated with dysfunction of the Hancock valve.

  14. Mitral Valve Mechanics Following Posterior Leaflet Patch Augmentation

    PubMed Central

    Rahmani, Azadeh; Rasmussen, Ann Q.; Honge, Jesper L.; Ostli, Bjorn; Levine, Robert A.; Hagège, Albert; Nygaard, Hans; Nielsen, Sten L.; Jensen, Morten O.

    2013-01-01

    Background and aim of the study Attention towards the optimization of mitral valve repair methods is increasing. Patch augmentation is one strategy used to treat functional ischemic mitral regurgitation (FIMR). The study aim was to investigate the force balance changes in specific chordae tendineae emanating from the posterior papillary muscle in a FIMR-simulated valve, following posterior leaflet patch augmentation. Methods Mitral valves were obtained from 12 pigs (body weight 80 kg). An in vitro test set-up simulating the left ventricle was used to hold the valves. The left ventricular pressure was regulated with water to simulate different static pressures during valve closure. A standardized oval pericardial patch (17 × 29 mm) was introduced into the posterior leaflet from mid P2 to the end of the P3 scallop. Dedicated miniature transducers were used to record the forces exerted on the chordae tendineae. Data were acquired before and after 12 mm posterior and 5 mm apical posterior papillary muscle displacement to simulate the effect from one of the main contributors of FIMR, before and after patch augmentation. Results The effect of displacing the posterior papillary muscle induced tethering on the intermediate chordae tendineae to the posterior leaflet, and resulted in a 39.8% force increase (p = 0.014). Posterior leaflet patch augmentation of the FIMR valve induced a 31.1% force decrease (p = 0.007). There was no difference in force between the healthy and the repaired valve simulations (p = 0.773). Conclusion Posterior leaflet patch augmentation significantly reduced the forces exerted on the intermediate chordae tendineae from the posterior papillary muscle following FIMR simulation. As changes in chordal tension lead to a redistribution of the total stress exerted on the valve, patch augmentation may have an adverse long-term influence on mitral valve function and remodeling. PMID:23610985

  15. Biomechanical evaluation of the pathophysiologic developmental mechanisms of mitral valve prolapse: effect of valvular morphologic alteration.

    PubMed

    Choi, Ahnryul; McPherson, David D; Kim, Hyunggun

    2016-05-01

    Mitral valve prolapse (MVP) refers to an excessive billowing of the mitral valve (MV) leaflets across the mitral annular plane into the left atrium during the systolic portion of the cardiac cycle. The underlying mechanisms for the development of MVP and mitral regurgitation in association with MV tissue remodeling are still unclear. We performed computational MV simulations to investigate the pathophysiologic developmental mechanisms of MVP. A parametric MV geometry model was utilized for this study. Posterior leaflet enlargement and posterior chordal elongation models were created by adjusting the geometry of the posterior leaflet and chordae, respectively. Dynamic finite element simulations of MV function were performed over the complete cardiac cycle. Computational simulations demonstrated that enlarging posterior leaflet area increased large stress concentration in the posterior leaflets and chordae, and posterior chordal elongation decreased leaflet coaptation. When MVP was accompanied by both posterior leaflet enlargement and chordal elongation simultaneously, the posterior leaflet was exposed to extremely large prolapse with a substantial lack of leaflet coaptation. These data indicate that MVP development is closely related to tissue alterations of the leaflets and chordae. This biomechanical evaluation strategy can help us better understand the pathophysiologic developmental mechanisms of MVP.

  16. Transcatheter aortic valve implantation in a patient with mechanical mitral prosthesis: a lesson learned from an intraventricular clash.

    PubMed

    Testa, Luca; Gelpi, Guido; Bedogni, Francesco

    2013-10-01

    We hereby present the case of a patient with severe aortic stenosis who underwent in her previous medical history a mitral valve replacement with a mechanical valve (Omnicarbon 27), and progressively developed a severe aortic stenosis. This patient was judged inoperable and then scheduled for CoreValve Revalving System implantation. Despite a good positioning of the CoreValve, an acute, severe mitral regurgitation developed soon after implantation as a consequence of the impaired movement of the mitral prosthesis leaflet. A condition of cardiogenic shock quickly developed. A good mitral prosthesis function was restored disengaging the CoreValve from the aortic annulus. After few months, the patients underwent successful Edwards-Sapien valve implantation through the Corevalve. This case strongly demonstrates how much a careful evaluation of the features of the mitral prosthesis and patient anatomy is crucial to select which specific transcatheter bioprosthesis would better perform.

  17. MECHANICAL DESIGN CRITERIA FOR INTERVERTEBRAL DISC TISSUE ENGINEERING

    PubMed Central

    Nerurkar, Nandan L.; Elliott, Dawn M.; Mauck, Robert L.

    2009-01-01

    Due to the inability of current clinical practices to restore function to degenerated intervertebral discs, the arena of disc tissue engineering has received substantial attention in recent years. Despite tremendous growth and progress in this field, translation to clinical implementation has been hindered by a lack of well-defined functional benchmarks. Because successful replacement of the disc is contingent upon replication of some or all of its complex mechanical behaviour, it is critically important that disc mechanics be well characterized in order to establish discrete functional goals for tissue engineering. In this review, the key functional signatures of the intervertebral disc are discussed and used to propose a series of native tissue benchmarks to guide the development of engineered replacement tissues. These benchmarks include measures of mechanical function under tensile, compressive and shear deformations for the disc and its substructures. In some cases, important functional measures are identified that have yet to be measured in the native tissue. Ultimately, native tissue benchmark values are compared to measurements that have been made on engineered disc tissues, identifying measures where functional equivalence was achieved, and others where there remain opportunities for advancement. Several excellent reviews exist regarding disc composition and structure, as well as recent tissue engineering strategies; therefore this review will remain focused on the functional aspects of disc tissue engineering. PMID:20080239

  18. Mechanical haemolytic anaemia after valve repair operations for non-rheumatic mitral regurgitation.

    PubMed Central

    Warnes, C; Honey, M; Brooks, N; Davies, J; Gorman, A; Parker, N

    1980-01-01

    Two cases are described in which severe mechanical haemolytic anaemia developed shortly after operation for repair of non-rheumatic mitral regurgitation. One patient had a "floppy" valve and the other cleft mitral leaflets, and both had chordal rupture. In both there was residual regurgitation after repair though in one this was initially only trivial. Clinically manifest haemolysis ceased after replacement of the valve by a frame-mounted xenograft. There are two previously reported cases in which haemolytic anaemia followed an unsuccessful mitral valve repair operation. Subclinical haemolysis or mild haemolytic anaemia may occur with unoperated valve lesions, but hitherto frank haemolytic anaemia has been observed only when turbulent blood flow is associated with the presence of a prosthetic valve or patch of prosthetic fabric. In these four cases, however, polyester or Teflon sutures were the only foreign material, and it is suggested that when these are used for the repair of leaflets, particularly in non-rheumatic mitral valve disease, they may increase the damaging effect of turbulence on circulating red blood cells. PMID:7426198

  19. Mechanisms for mechanical damage in the intervertebral disc annulus fibrosus.

    PubMed

    Iatridis, J C James C; ap Gwynn, Iolo

    2004-08-01

    Intervertebral disc degeneration results in disorganization of the laminate structure of the annulus that may arise from mechanical microfailure. Failure mechanisms in the annulus were investigated using composite lamination theory and other analyses to calculate stresses in annulus layers, interlaminar shear stress, and the region of stress concentration around a fiber break. Scanning electron microscopy (SEM) was used to evaluate failure patterns in the annulus and evaluate novel structural features of the disc tissue. Stress concentrations in the annulus due to an isolated fiber break were localized to approximately 5 microm away from the break, and only considered a likely cause of annulus fibrosus failure (i.e., radial tears in the annulus) under extreme loading conditions or when collagen damage occurs over a relatively large region. Interlaminar shear stresses were calculated to be relatively large, to increase with layer thickness (as reported with degeneration), and were considered to be associated with propagation of circumferential tears in the annulus. SEM analysis of intervertebral disc annulus fibrosus tissue demonstrated a clear laminate structure, delamination, matrix cracking, and fiber failure. Novel structural features noted with SEM also included the presence of small tubules that appear to run along the length of collagen fibers in the annulus and a distinct collagenous structure representative of a pericellular matrix in the nucleus region.

  20. Left ventricular mechanics in isolated mild mitral stenosis: a three dimensional speckle tracking study.

    PubMed

    Poyraz, Esra; Öz, Tuğba Kemaloğlu; Zeren, Gönül; Güvenç, Tolga Sinan; Dönmez, Cevdet; Can, Fatma; Güvenç, Rengin Çetin; Dayı, Şennur Ünal

    2017-03-11

    In a fraction of patients with mild mitral stenosis, left ventricular systolic function deteriorates despite the lack of hemodynamic load imposed by the dysfunctioning valve. Neither the predisposing factors nor the earlier changes in left ventricular contractility were understood adequately. In the present study we aimed to evaluate left ventricular mechanics using three-dimensional (3D) speckle tracking echocardiography. A total of 31 patients with mild rheumatic mitral stenosis and 27 healthy controls were enrolled to the study. All subjects included to the study underwent echocardiographic examination to collect data for two- and three-dimensional speckle-tracking based stain, twist angle and torsion measurements. Data was analyzed offline with a echocardiographic data analysis software. Patients with rheumatic mild MS had lower global longitudinal (p < 0.001) circumferential (p = 0.02) and radial (p < 0.01) strain compared to controls, despite ejection fraction was similar for both groups [(p = 0.45) for three dimensional and (p = 0.37) for two dimensional measurement]. While the twist angle was not significantly different between groups (p = 0.11), left ventricular torsion was significantly higher in mitral stenosis group (p = 0.03). All strain values had a weak but significant positive correlation with mitral valve area measured with planimetry. Subclinical left ventricular systolic dysfunction develops at an early stage in rheumatic mitral stenosis. Further work is needed to elucidate patients at risk for developing overt systolic dysfunction.

  1. Mechanics of the mitral valve: a critical review, an in vivo parameter identification, and the effect of prestrain.

    PubMed

    Rausch, Manuel K; Famaey, Nele; Shultz, Tyler O'Brien; Bothe, Wolfgang; Miller, D Craig; Kuhl, Ellen

    2013-10-01

    Alterations in mitral valve mechanics are classical indicators of valvular heart disease, such as mitral valve prolapse, mitral regurgitation, and mitral stenosis. Computational modeling is a powerful technique to quantify these alterations, to explore mitral valve physiology and pathology, and to classify the impact of novel treatment strategies. The selection of the appropriate constitutive model and the choice of its material parameters are paramount to the success of these models. However, the in vivo parameters values for these models are unknown. Here, we identify the in vivo material parameters for three common hyperelastic models for mitral valve tissue, an isotropic one and two anisotropic ones, using an inverse finite element approach. We demonstrate that the two anisotropic models provide an excellent fit to the in vivo data, with local displacement errors in the sub-millimeter range. In a complementary sensitivity analysis, we show that the identified parameter values are highly sensitive to prestrain, with some parameters varying up to four orders of magnitude. For the coupled anisotropic model, the stiffness varied from 119,021 kPa at 0 % prestrain via 36 kPa at 30 % prestrain to 9 kPa at 60 % prestrain. These results may, at least in part, explain the discrepancy between previously reported ex vivo and in vivo measurements of mitral leaflet stiffness. We believe that our study provides valuable guidelines for modeling mitral valve mechanics, selecting appropriate constitutive models, and choosing physiologically meaningful parameter values. Future studies will be necessary to experimentally and computationally investigate prestrain, to verify its existence, to quantify its magnitude, and to clarify its role in mitral valve mechanics.

  2. Mechanical dyssynchrony and deformation imaging in patients with functional mitral regurgitation

    PubMed Central

    Rosa, Isabella; Marini, Claudia; Stella, Stefano; Ancona, Francesco; Spartera, Marco; Margonato, Alberto; Agricola, Eustachio

    2016-01-01

    Chronic functional mitral regurgitation (FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy (DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in FMR, such as annular dilatation and dysfunction, left ventricle (LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy (CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different mechanisms: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. Deformation imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve deformation indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome. PMID:26981211

  3. Mechanical dyssynchrony and deformation imaging in patients with functional mitral regurgitation.

    PubMed

    Rosa, Isabella; Marini, Claudia; Stella, Stefano; Ancona, Francesco; Spartera, Marco; Margonato, Alberto; Agricola, Eustachio

    2016-02-26

    Chronic functional mitral regurgitation (FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy (DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in FMR, such as annular dilatation and dysfunction, left ventricle (LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy (CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different mechanisms: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. Deformation imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve deformation indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome.

  4. Molecular Mechanisms of Biological Aging in Intervertebral Discs

    PubMed Central

    Vo, Nam V.; Hartman, Robert A.; Patil, Prashanti R.; Risbud, Makarand V.; Kletsas, Dimitris; Iatridis, James C.; Hoyland, Judith A.; Le Maitre, Christine L.; Sowa, Gwendolyn A.; Kang, James D.

    2016-01-01

    Advanced age is the greatest risk factor for the majority of human ailments, including spine-related chronic disability and back pain, which stem from age-associated intervertebral disc degeneration (IDD). Given the rapid global rise in the aging population, understanding the biology of intervertebral disc aging in order to develop effective therapeutic interventions to combat the adverse effects of aging on disc health is now imperative. Fortunately, recent advances in aging research have begun to shed light on the basic biological process of aging. Here we review some of these insights and organize the complex process of disc aging into three different phases to guide research efforts to understand the biology of disc aging. The objective of this review is to provide an overview of the current knowledge and the recent progress made to elucidate specific molecular mechanisms underlying disc aging. In particular, studies over the last few years have uncovered cellular senescence and genomic instability as important drivers of disc aging. Supporting evidence comes from DNA repair-deficient animal models that show increased disc cellular senescence and accelerated disc aging. Additionally, stress-induced senescent cells have now been well documented to secrete catabolic factors, which can negatively impact the physiology of neighboring cells and ECM. These along with other molecular drivers of aging are reviewed in depth to shed crucial insights into the underlying mechanisms of age-related disc degeneration. We also highlight molecular targets for novel therapies and emerging candidate therapeutics that may mitigate age-associated IDD. PMID:26890203

  5. Mechanism of Microbubble Growth at Mitral Mechanical Heart Valve (MHV) Closure

    NASA Astrophysics Data System (ADS)

    Rambod, Edmond; Beizaie, Masoud; Shusser, Michael; Gharib, Morteza

    1999-11-01

    The growth mechanism of microbubbles at mitral MHV closure has been experimentally studied. In the heart, some of the tiny bubbles grow explosively and form larger and persistent bubbles. An experimental set-up was designed to allow the passage of micron-size bubbles through an 80 micron-wide slot, simulating a typical gap between the housing ring and the occluders in MHV. The bubbles were generated using an air-liquid dispenser and were delivered to the system via a 250 micron-diameter hypedermic needle positioned vertically near the slot. A solenoid valve was used to deliver a 10cc volume of liquid in 25ms time through the slot. High-speed imaging was used to study the impact of flow through the slot on bubble growth. The velocity of liquid through the slot was assessed to be in the range of 12-15 m/s. Our observations confirmed the rapid and drastic growth of microbubbles following their passage through the narrow slot, due to pressure drop. Vortices, which were induced by flow separation on the downstream of the slot, caused the grown bubbles to shatter and form more stable bubbles.

  6. Cardiogenic unilateral pulmonary oedema in an infant with severe residual mitral regurgitation.

    PubMed

    Joong, Anna; Lai, Wyman W; Ferris, Anne

    2017-01-01

    An infant with residual severe mitral regurgitation following mitral commissurotomy developed cardiogenic unilateral pulmonary oedema and subsegmental atelectasis that resolved with mechanical mitral valve replacement.

  7. A novel left heart simulator for the multi-modality characterization of native mitral valve geometry and fluid mechanics.

    PubMed

    Rabbah, Jean-Pierre; Saikrishnan, Neelakantan; Yoganathan, Ajit P

    2013-02-01

    Numerical models of the mitral valve have been used to elucidate mitral valve function and mechanics. These models have evolved from simple two-dimensional approximations to complex three-dimensional fully coupled fluid structure interaction models. However, to date these models lack direct one-to-one experimental validation. As computational solvers vary considerably, experimental benchmark data are critically important to ensure model accuracy. In this study, a novel left heart simulator was designed specifically for the validation of numerical mitral valve models. Several distinct experimental techniques were collectively performed to resolve mitral valve geometry and hemodynamics. In particular, micro-computed tomography was used to obtain accurate and high-resolution (39 μm voxel) native valvular anatomy, which included the mitral leaflets, chordae tendinae, and papillary muscles. Three-dimensional echocardiography was used to obtain systolic leaflet geometry. Stereoscopic digital particle image velocimetry provided all three components of fluid velocity through the mitral valve, resolved every 25 ms in the cardiac cycle. A strong central filling jet (V ~ 0.6 m/s) was observed during peak systole with minimal out-of-plane velocities. In addition, physiologic hemodynamic boundary conditions were defined and all data were synchronously acquired through a central trigger. Finally, the simulator is a precisely controlled environment, in which flow conditions and geometry can be systematically prescribed and resultant valvular function and hemodynamics assessed. Thus, this work represents the first comprehensive database of high fidelity experimental data, critical for extensive validation of mitral valve fluid structure interaction simulations.

  8. Characterizing thermal sweeping: a rapid disc dispersal mechanism

    NASA Astrophysics Data System (ADS)

    Owen, James E.; Hudoba de Badyn, Mathias; Clarke, Cathie J.; Robins, Luke

    2013-12-01

    We consider the properties of protoplanetary discs that are undergoing inside-out clearing by photoevaporation. In particular, we aim to characterize the conditions under which a protoplanetary disc may undergo `thermal sweeping', a rapid (≲104 years) disc destruction mechanism proposed to occur when a clearing disc reaches sufficiently low surface density at its inner edge and where the disc is unstable to runaway penetration by the X-rays. We use a large suite of 1D radiation-hydrodynamic simulations to probe the observable parameter space, which is unfeasible in higher dimensions. These models allow us to determine the surface density at which thermal sweeping will take over the disc's evolution and to evaluate this critical surface density as a function of X-ray luminosity, stellar mass and inner hole radius. We find that this critical surface density scales linearly with X-ray luminosity, increases with inner hole radius and decreases with stellar mass, and we develop an analytic model that reproduces these results. This surface density criterion is then used to determine the evolutionary state of protoplanetary discs at the point that they become unstable to destruction by thermal sweeping. We find that transition discs created by photoevaporation will undergo thermal sweeping when their inner holes reach 20-40 au, implying that transition discs with large holes and no accretion (which were previously a predicted outcome of the later stages of all flavours of the photoevaporation model) will not form. Thermal sweeping thus avoids the production of large numbers of large, non-accreting holes (which are not observed) and implies that the majority of holes created by photoevaporation should still be accreting. We emphasize that the surface density criteria that we have developed apply to all situations where the disc develops an inner hole that is optically thin to X-rays. It thus applies not only to the case of holes originally created by photoevaporation but

  9. Effects of suture position on left ventricular fluid mechanics under mitral valve edge-to-edge repair.

    PubMed

    Du, Dongxing; Jiang, Song; Wang, Ze; Hu, Yingying; He, Zhaoming

    2014-01-01

    Mitral valve (MV) edge-to-edge repair (ETER) is a surgical procedure for the correction of mitral valve regurgitation by suturing the free edge of the leaflets. The leaflets are often sutured at three different positions: central, lateral and commissural portions. To study the effects of position of suture on left ventricular (LV) fluid mechanics under mitral valve ETER, a parametric model of MV-LV system during diastole was developed. The distribution and development of vortex and atrio-ventricular pressure under different suture position were investigated. Results show that the MV sutured at central and lateral in ETER creates two vortex rings around two jets, compared with single vortex ring around one jet of the MV sutured at commissure. Smaller total orifices lead to a higher pressure difference across the atrio-ventricular leaflets in diastole. The central suture generates smaller wall shear stresses than the lateral suture, while the commissural suture generated the minimum wall shear stresses in ETER.

  10. Clinical and necropsy observations early after simultaneous replacement of the mitral and aortic valves.

    PubMed

    Roberts, W C; Sullivan, M F

    1986-11-15

    Clinical and necropsy findings are described in 54 patients, aged 25 to 83 years (mean 53), who died within 60 days of simultaneous replacements of both mitral and aortic valves. The patients were separated into 4 groups on the basis of the presence of stenosis (with or without associated regurgitation) or pure regurgitation of each valve: 30 patients (56%) had combined mitral and aortic valve stenosis; 12 patients (22%) had mitral stenosis and pure aortic regurgitation; 8 patients (15%) had pure regurgitation of both valves; and 4 patients (7%) had pure aortic regurgitation and mitral stenosis. Necropsy examination in the 54 patients disclosed a high frequency (48%) of anatomic evidence of interference to poppet or disc movement in either the mitral or aortic valve position or both. Anatomic evidence of interference to movement of a poppet or disc in the aortic valve position was twice as common as anatomic evidence of interference to poppet or disc movement in the mitral position. Interference to poppet movement is attributable to the prosthesis's being too large for the ascending aorta or left ventricular cavity in which it resided. The ascending aorta is infrequently enlarged in patients with combined mitral and aortic valve dysfunction irrespective of whether the aortic valve is stenotic or purely regurgitant. Likewise, the left ventricular cavity is usually not dilated in patients with combined mitral and aortic valve stenosis, the most common indication for replacement of both left-sided cardiac valves. Of the 54 patients, 12 (22%) had 1 mechanical and 1 bioprosthesis inserted. It is recommended that both substitute valves should be mechanical prostheses or both should be bioprostheses.

  11. Transfemoral implantation of CoreValve Evolut-R aortic prosthesis in patient with prior ball-cage mechanical mitral valve prosthesis.

    PubMed

    Maluenda, Gabriel; Caorsi, Carlos; Baeza, Cristian

    2016-06-01

    Transcatheter aortic valve replacement remains challenge in patients with ball-cage-type mechanical valve in mitral position. Potential under-expansion of the percutaneous valve and interaction between the mitral ball-cage mechanical valve tilted towards the left ventricular outflow tract and the percutaneous valve adds risk during and after implantation. We report a successful implantation of the novel CoreValve Evolut-R self-expanding in a patient with severe aortic stenosis and a mitral Starr-Edwards mechanical valve implanted 28years ago.

  12. Prediction of glycosaminoglycan synthesis in intervertebral disc under mechanical loading.

    PubMed

    Gao, Xin; Zhu, Qiaoqiao; Gu, Weiyong

    2016-09-06

    The loss of glycosaminoglycan (GAG) content is a major biochemical change during intervertebral disc (IVD) degeneration. Abnormal mechanical loading is one of the major factors causing disc degeneration. In this study, a multiscale mathematical model was developed to quantify the effect of mechanical loading on GAG synthesis. This model was based on a recently developed cell volume dependent GAG synthesis theory that predicts the variation of GAG synthesis rate of a cell under the influence of mechanical stimuli, and the biphasic theory that describes the deformation of IVD under mechanical loading. The GAG synthesis (at the cell level) was coupled with the mechanical loading (at the tissue level) via a cell-matrix unit approach which established a relationship between the variation of cell dilatation and the local tissue dilatation. This multiscale mathematical model was used to predict the effect of static load (creep load) on GAG synthesis in bovine tail discs. The predicted results are in the range of experimental results. This model was also used to investigate the effect of static (0.2MPa) and diurnal loads (0.1/0.3MPa and 0.15/0.25MPa in 12/12 hours shift with an average of 0.2MPa over a cycle) on GAG synthesis. It was found that static load and diurnal loads have different effects on GAG synthesis in a diurnal cycle, and the diurnal load effects depend on the amplitude of the load. The model is important to understand the effect of mechanical loading at the tissue level on GAG synthesis at the cellular level, as well as to optimize the mechanical loading in growing engineered tissue.

  13. Bench Models for Assessing the Mechanics of Mitral Valve Repair and Percutaneous Surgery.

    PubMed

    Siefert, Andrew W; Siskey, Ryan L

    2015-06-01

    Rapid preclinical evaluations of mitral valve (MV) mechanics are currently best facilitated by bench models of the left ventricle (LV). This review aims to provide a comprehensive assessment of these models to aid interpretation of their resulting data, inform future experimental evaluations, and further the translation of results to procedure and device development. For this review, two types of experimental bench models were evaluated. Rigid LV models were characterized as fluid-mechanical systems capable of testing explanted MVs under static and or pulsatile left heart hemodynamics. Passive LV models were characterized as explanted hearts whose left side is placed in series with a static or pulsatile flow-loop. In both systems, MV function and mechanics can be quantitatively evaluated. Rigid and passive LV models were characterized and evaluated. The materials and methods involved in their construction, function, quantitative capabilities, and disease modeling were described. The advantages and disadvantages of each model are compared to aid the interpretation of their resulting data and inform future experimental evaluations. Repair and percutaneous studies completed in these models were additionally summarized with perspective on future advances discussed. Bench models of the LV provide excellent platforms for quantifying MV repair mechanics and function. While exceptional work has been reported, more research and development is necessary to improve techniques and devices for repair and percutaneous surgery. Continuing efforts in this field will significantly contribute to the further development of procedures and devices, predictions of long-term performance, and patient safety.

  14. Wide range force feedback for catheter insertion mechanism for use in minimally invasive mitral valve repair surgery

    NASA Astrophysics Data System (ADS)

    Ahmadi, Roozbeh; Sokhanvar, Saeed; Packirisamy, Muthukumaran; Dargahi, Javad

    2009-02-01

    Mitral valve regurgitation (MR) is a condition in which heart's mitral valve does not close tightly, which allows blood to leak back into the left atrium. Restoring the dimension of the mitral-valve annulus by percutaneous intervention surgery is a common choice to treat MR. Currently, this kind of open heart annuloplasty surgery is being performed through sternotomy with cardiomyopathy bypass. In order to reduce trauma to the patient and also to eliminate bypass surgery, robotic assisted minimally invasive surgery (MIS) procedure, which requires small keyhole incisions, has a great potential. To perform this surgery through MIS procedure, an accurate computer controlled catheter with wide-range force feedback capabilities is required. There are three types of tissues at the site of operation: mitral leaflet, mitral annulus and left atrium. The maximum allowable applied force to these three types of tissue is totally different. For instance, leaflet tissue is the most sensitive one with the lowest allowable force capacity. For this application, therefore, a wide-range force sensing is highly required. Most of the sensors that have been developed for use in MIS applications have a limited range of sensing. Therefore, they need to be calibrated for different types of tissue. The present work, reports on the design, modeling and simulation of a novel wide-range optical force sensor for measurement of contact pressure between catheter tip and heart tissue. The proposed sensor offers a wide input range with a high resolution and sensitivity over this range. Using Micro-Electro-Mechanical-Systems (MEMS) technology, this sensor can be microfabricated and integrated with commercially available catheters.

  15. Shock absorption in lumbar disc prosthesis: a preliminary mechanical study.

    PubMed

    LeHuec, J C; Kiaer, T; Friesem, T; Mathews, H; Liu, M; Eisermann, L

    2003-08-01

    Lumbar disc prostheses have been used in treating symptomatic degenerative disc diseases. A few prostheses of the ball-socket design are currently available for clinical use, the joint mechanism being materialized either with a hard polymer core or a metal-to-metal couple. Other prostheses of "shock absorber" design were not available at the time of the study. The objective of this work was to establish whether there was a difference in the shock absorption capacity between a device having an ultra-high-molecular-weight polyethylene center core and a device having a metal-on-metal bearing. Vibration and shock loading were applied to two lumbar total disc prostheses: PRODISC, manufactured by Spine Solutions, and MAVERICK Total Disc Replacement, manufactured by Medtronic Sofamor Danek. The shock absorption capacity of the device was evaluated by comparing the input and the output force measurements. The disc prosthesis was mounted onto a test apparatus. Each side of the device was equipped with a force sensor. The input shock load and the output resulting forces were simultaneously measured and recorded. The loading force pattern included 1). a static preload of 350 N plus an oscillating vibration of 100 N with frequency sweeping from 0 to 100 Hz and 2). a sudden shock load of 250 N applied over a 0.1-second interval. Both input and output signal data were processed and were transformed into their frequency spectrums. The vibration and shock transmissibility of the device, defined as the ratio of the output spectrum over the input spectrum, were calculated in sweeping the frequency from 0 to 100 Hz. The phase deviation was calculated to characterize the shock absorber effects. For both tested devices under vibration and shock loading, the phase angle displacement between the input and the output signals was 10 degrees. Under oscillating vibration loading, both tested devices had a transmission ratio higher than 99.8%. Over the frequency interval 1-100 Hz, the

  16. Early Clinical Outcome of Mitral Valve Replacement Using a Newly Designed Stentless Mitral Valve for Failure of Initial Mitral Valve Repair.

    PubMed

    Nishida, Hidefumi; Kasegawa, Hitoshi; Kin, Hajime; Takanashi, Shuichiro

    2016-12-21

    Here we report the early outcome of mitral valve replacement using a newly designed stentless mitral valve for failure of initial mitral valve repair. Mitral valve plasty (MVP) for mitral regurgitation is currently a standard technique performed worldwide. However, whether mitral valve repair should be performed for patients with advanced leaflet damage or complicated pathology remains controversial. Mitral valve replacement might be feasible for patients who have undergone failed initial MVP; however, it is not an optimal treatment because of poor valve durability and the need for anticoagulative therapy. We report two cases of successful mitral valve replacement using a newly designed stentless mitral valve made of fresh autologous pericardium, which may have a potential benefit over mitral valve repair or mitral valve replacement with a mechanical or bioprosthetic valve.

  17. Morphofunctional Abnormalities of Mitral Annulus and Arrhythmic Mitral Valve Prolapse

    PubMed Central

    Basso, Cristina; De Lazzari, Manuel; Rizzo, Stefania; Cipriani, Alberto; Giorgi, Benedetta; Lacognata, Carmelo; Rigato, Ilaria; Migliore, Federico; Pilichou, Kalliopi; Cacciavillani, Luisa; Bertaglia, Emanuele; Frigo, Anna Chiara; Bauce, Barbara; Corrado, Domenico; Thiene, Gaetano; Iliceto, Sabino

    2016-01-01

    Background— Arrhythmic mitral valve prolapse (MVP) is characterized by myxomatous leaflets and left ventricular (LV) fibrosis of papillary muscles and inferobasal wall. We searched for morphofunctional abnormalities of the mitral valve that could explain a regional mechanical myocardial stretch. Methods and Results— Thirty-six (27 female patients; median age: 44 years) arrhythmic MVP patients with LV late gadolinium enhancement on cardiac magnetic resonance and no or trivial mitral regurgitation, and 16 (6 female patients; median age: 40 years) MVP patients without LV late gadolinium enhancement were investigated by morphofunctional cardiac magnetic resonance. Mitral annulus disjunction (median: 4.8 versus 1.8 mm; P<0.001), end-systolic mitral annular diameters (median: 41.2 versus 31.5; P=0.004) and end-diastolic mitral annular diameters (median: 35.5 versus 31.5; P=0.042), prevalence of posterior systolic curling (34 [94%] versus 3 [19%]; P<0.001), and basal to mid LV wall thickness ratio >1.5 (22 [61%] versus 4 [25%]; P=0.016) were higher in MVP patients with late gadolinium enhancement than in those without. A linear correlation was found between mitral annulus disjunction and curling (R=0.85). A higher prevalence of auscultatory midsystolic click (26 [72%] versus 6 [38%]; P=0.018) was also noted. Histology of the mitral annulus showed a longer mitral annulus disjunction in 50 sudden death patients with MVP and LV fibrosis than in 20 patients without MVP (median: 3 versus 1.5 mm; P<0.001). Conclusions— Mitral annulus disjunction is a constant feature of arrhythmic MVP with LV fibrosis. The excessive mobility of the leaflets caused by posterior systolic curling accounts for a mechanical stretch of the inferobasal wall and papillary muscles, eventually leading to myocardial hypertrophy and scarring. These mitral annulus abnormalities, together with auscultatory midsystolic click, may identify MVP patients who would need arrhythmic risk stratification. PMID

  18. Mitral stenosis

    MedlinePlus

    ... may then collect in the lung tissue (pulmonary edema), making it hard to breathe. In adults, mitral ... kidneys, or other areas Congestive heart failure Pulmonary edema Pulmonary hypertension When to Contact a Medical Professional ...

  19. Star GK Bileaflet Mechanical Valve Prosthesis-Patient Mismatch After Mitral Valve Replacement: A Chinese Multicenter Clinical Study

    PubMed Central

    Cao, Hua; Qiu, Zhihuang; Chen, Liangwan; Chen, Daozhong; Chen, Qiang

    2015-01-01

    Background The aim of this study was to investigate the incidence and immediate and mid-term effects of heart valve prosthesis-patient mismatch (PPM) after mitral valve replacement using the GK bileaflet mechanical valve. Material/Methods A total of 493 cases of mechanical mitral valve replacement were performed in the departments of cardiac surgery in 7 hospitals from January 2000 to January 2008. The patients included 142 men and 351 women ages 21 to 67 (average age, 48.75). The patients were followed for 3 years after surgery. The effective orifice area index (EOAI), ≤1.2 cm2/m2, was detected during the follow-up period and was defined as PPM. The patients were assigned to either the PPM group or the non-PPM group. Finally, the preoperative, perioperative and postoperative indexes of the 2 groups of patients were compared. Results A total of 157 patients had PPM 3 years after surgery. The incidence of PPM was 31.84%. Sixty-three patients in the PPM group received a 25-mm GK bileaflet valve (40.13%), 82 received a 27-mm valve (52.23%), and 12 (7.64%) received a 29-mm valve. There were significant differences in length of intensive care unit stay, duration of ventilator use, length of hospitalization, body surface area, EOAI, mean transmitral pressure gradient, and pulmonary artery pressure between the PPM and non-PPM group (P<0.05). There was a significant difference between preoperative and postoperative pulmonary artery pressures among non-PPM patients (P<0.05); however, there was no statistical difference in preoperative and postoperative pulmonary artery pressures among patients with PPM (P>0.05). Conclusions PPM after mitral valve replacement influences postoperative hemodynamics. Thus, larger-sized GK bileaflet mechanical valves are often used to reduce the risk of PPM. PMID:26313311

  20. Mitral mechanical valve without long-term anticoagulation. Eight-year follow-up.

    PubMed

    Björk, V O; Ribeiro, A; Canetti, M; Bomfim, V

    1994-01-01

    In 12 patients with sinus rhythm (including 5 children and 6 young women), mitral valve replacement was performed with a microporous-surfaced valve similar to the Björk-Shiley Monostrut. After the first 3 months, permitting endothelialization of the suture ring to continue over the groove and adjacent metal valve ring, no long-term anticoagulant treatment was given. There was no thromboembolic complication in this group during follow-up for 6-8 years, during which four women gave birth to a total of seven children. In eight other cases, one mitral case with atrial fibrillation, anti-coagulant was not discontinued, and in the remaining aortic cases it was reinstituted. One of them (with atrial fibrillation) had hematuria during inadequate anticoagulant medication, but no thromboembolism. Of five patients with only aortic valve replacement, two had thromboembolic complications, one without residual symptoms and one with slight hand weakness. Another had a transient ischemic attack while on anticoagulant and acetylsalicylic acid was added. Two patients with aortic and mitral valve replacement died, one from heart tamponade and the other from venous thrombosis with pulmonary embolism.

  1. The Relation Between Collagen Fibril Kinematics and Mechanical Properties in the Mitral Valve Anterior Leaflet

    SciTech Connect

    Liao,J.; Yang, L.; Grashow, J.; Sacks, M.

    2007-01-01

    We have recently demonstrated that the mitral valve anterior leaflet (MVAL) exhibited minimal hysteresis, no strain rate sensitivity, stress relaxation but not creep (Grashow et al., 2006, Ann Biomed Eng., 34(2), pp. 315-325; Grashow et al., 2006, Ann Biomed. Eng., 34(10), pp. 1509-1518). However, the underlying structural basis for this unique quasi-elastic mechanical behavior is presently unknown. As collagen is the major structural component of the MVAL, we investigated the relation between collagen fibril kinematics (rotation and stretch) and tissue-level mechanical properties in the MVAL under biaxial loading using small angle X-ray scattering. A novel device was developed and utilized to perform simultaneous measurements of tissue level forces and strain under a planar biaxial loading state. Collagen fibril D-period strain ({epsilon}{sub D}) and the fibrillar angular distribution were measured under equibiaxial tension, creep, and stress relaxation to a peak tension of 90 N/m. Results indicated that, under equibiaxial tension, collagen fibril straining did not initiate until the end of the nonlinear region of the tissue-level stress-strain curve. At higher tissue tension levels, {epsilon}{sub D} increased linearly with increasing tension. Changes in the angular distribution of the collagen fibrils mainly occurred in the tissue toe region. Using {epsilon}{sub D}, the tangent modulus of collagen fibrils was estimated to be 95.5{+-}25.5 MPa, which was {approx}27 times higher than the tissue tensile tangent modulus of 3.58{+-}1.83 MPa. In creep tests performed at 90 N/m equibiaxial tension for 60 min, both tissue strain and D remained constant with no observable changes over the test length. In contrast, in stress relaxation tests performed for 90 min {epsilon}{sub D} was found to rapidly decrease in the first 10 min followed by a slower decay rate for the remainder of the test. Using a single exponential model, the time constant for the reduction in collagen

  2. Are the Current Doppler Echocardiography Criteria Able to Discriminate Mitral Bileaflet Mechanical Heart Valve Malfunction? An In Vitro Study.

    PubMed

    Evin, Morgane; Guivier-Curien, Carine; Pibarot, Philippe; Kadem, Lyes; Rieu, Régis

    2016-05-01

    Malfunction of bileaflet mechanical heart valves in the mitral position could either be due to patient-prosthesis mismatch (PPM) or leaflet obstruction. The aim of this article is to investigate the validity of current echocardiographic criteria used for diagnosis of mitral prosthesis malfunction, namely maximum velocity, mean transvalvular pressure gradient, effective orifice area, and Doppler velocity index. In vitro testing was performed on a double activation left heart duplicator. Both PPM and leaflet obstruction were investigated on a St. Jude Medical Master. PPM was studied by varying the St. Jude prosthesis size (21, 25, and 29 mm) and stroke volume (70 and 90 mL). Prosthesis leaflet obstruction was studied by partially or totally blocking the movement of one valve leaflet. Mitral flow conditions were altered in terms of E/A ratios (0.5, 1.0, and 1.5) to simulate physiologic panel of diastolic function. Maximum velocity, effective orifice area, and Doppler velocity index are shown to be insufficient to distinguish normal from malfunctioning St. Jude prostheses. Doppler velocity index and effective orifice area were 1.3 ± 0.49 and 1.83 ± 0.43 cm(2) for testing conditions with no malfunction below the 2.2 and 2 cm(2) thresholds (1.19 cm(2) for severe PPM and 1.23 cm(2) for fully blocked leaflet). The mean pressure gradient reached 5 mm Hg thresholds for several conditions of severe PPM only (6.9 mm Hg and mean maximum velocity value: 183.4 cm/s) whereas such value was never attained in the case of leaflet obstruction. In the case of leaflet obstruction, the maximum velocity averaged over the nine pulsed-wave Doppler locations increased by 38% for partial leaflet obstruction and 75% for a fully blocked leaflet when compared with normal conditions. Current echocardiographic criteria might be suboptimal for the detection of bileaflet mechanical heart valve malfunction. Further developments and investigations are required in order

  3. The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time

    NASA Astrophysics Data System (ADS)

    Grand, Robert J. J.; Gómez, Facundo A.; Marinacci, Federico; Pakmor, Rüdiger; Springel, Volker; Campbell, David J. R.; Frenk, Carlos S.; Jenkins, Adrian; White, Simon D. M.

    2017-01-01

    We introduce a suite of thirty cosmological magneto-hydrodynamical zoom simulations of the formation of galaxies in isolated Milky Way mass dark haloes. These were carried out with the moving mesh code AREPO, together with a comprehensive model for galaxy formation physics, including AGN feedback and magnetic fields, which produces realistic galaxy populations in large cosmological simulations. We demonstrate that our simulations reproduce a wide range of present-day observables, in particular, two component disc dominated galaxies with appropriate stellar masses, sizes, rotation curves, star formation rates and metallicities. We investigate the driving mechanisms that set present-day disc sizes/scale lengths, and find that they are related to the angular momentum of halo material. We show that the largest discs are produced by quiescent mergers that inspiral into the galaxy and deposit high angular momentum material into the pre-existing disc, simultaneously increasing the spin of dark matter and gas in the halo. More violent mergers and strong AGN feedback play roles in limiting disc size by destroying pre-existing discs and by suppressing gas accretion onto the outer disc, respectively. The most important factor that leads to compact discs, however, is simply a low angular momentum for the halo. In these cases, AGN feedback plays an important role in limiting central star formation and the formation of a massive bulge.

  4. Ischemic mitral valve prolapse

    PubMed Central

    Cristiano, Spadaccio; Nenna, Antonio; Chello, Massimo

    2016-01-01

    Ischemic mitral prolapse (IMP) is a pathologic entity encountered in about one-third among the patients undergoing surgery for ischemic mitral regurgitation (IMR). IMP is generally the result of a papillary muscle injury consequent to myocardial, but the recent literature is progressively unveiling a more complex pathogenesis. The mechanisms underlying its development regards the impairment of one or more components of the mitral apparatus, which comprises the annulus, the chordae tendineae, the papillary muscle and the left ventricular wall. IMP is not only a disorder of valvular function, but also entails coexistent aspects of a geometric disturbance of the mitral valve configuration and of the left ventricular function and dimension and a correct understanding of all these aspects is crucial to guide and tailor the correct therapeutic strategy to be adopted. Localization of prolapse, anatomic features of the prolapsed leaflets and the subvalvular apparatus should be carefully evaluated as also constituting the major determinants defining patient’s outcomes. This review will summarize our current understanding of the pathophysiology and clinical evidence on IMP with a particular focus on the surgical treatment. PMID:28149574

  5. Assessment of trans-aortic pressure gradient using a coronary pressure wire in patients with mechanical aortic and mitral valve prostheses.

    PubMed

    Kherada, Nisharahmed; Brenes, Juan Carlos; Kini, Annapoorna S; Dangas, George D

    2017-03-15

    Accurate evaluation of trans-aortic valvular pressure gradients is challenging in cases where dual mechanical aortic and mitral valve prostheses are present. Non-invasive Doppler echocardiographic imaging has its limitations due to multiple geometric assumptions. Invasive measurement of trans-valvular gradients with cardiac catheterization can provide further information in patients with two mechanical valves, where simultaneous pressure measurements in the left ventricle and ascending aorta must be obtained. Obtaining access to the left ventricle via the mitral valve after a trans-septal puncture is not feasible in the case of a concomitant mechanical mitral valve, whereas left ventricular apical puncture technique is associated with high procedural risks. Retrograde crossing of a bileaflet mechanical aortic prosthesis with standard catheters is associated with the risk of catheter entrapment and acute valvular regurgitation. In these cases, the assessment of trans-valvular gradients using a 0.014˝ diameter coronary pressure wire technique has been described in a few case reports. We present the case of a 76-year-old female with rheumatic valvular heart disease who underwent mechanical aortic and mitral valve replacement in the past. She presented with decompensated heart failure and echocardiographic findings suggestive of elevated pressure gradient across the mechanical aortic valve prosthesis. The use of a high-fidelity 0.014˝ diameter coronary pressure guidewire resulted in the detection of a normal trans-valvular pressure gradient across the mechanical aortic valve. This avoided a high-risk third redo valve surgery in our patient. © 2017 Wiley Periodicals, Inc.

  6. Transventricular mitral valve operations.

    PubMed

    Joseph Woo, Y; McCormick, Ryan C

    2011-10-01

    We report transventricular mitral valve operations in 2 patients with severe mitral regurgitation and postinfarction left ventricular rupture and pseudoaneurysm. The first patient had direct papillary muscle involvement necessitating replacement of the mitral valve. The second patient had indirect mitral involvement allowing for placement of an atrial mitral annuloplasty ring via the left ventricle. Both patients showed no mitral valve regurgitation after replacement or repair and had uneventful postoperative recoveries. These cases demonstrate a feasible, alternative, transventricular approach to mitral valve replacement and repair.

  7. Mechanical Characterization of the Human Lumbar Intervertebral Disc Subjected to Impact Loading Conditions

    NASA Astrophysics Data System (ADS)

    Jamison, David, IV

    Low back pain is a large and costly problem in the United States. Several working populations, such as miners, construction workers, forklift operators, and military personnel, have an increased risk and prevalence of low back pain compared to the general population. This is due to exposure to repeated, transient impact shocks, particularly while operating vehicles or other machinery. These shocks typically do not cause acute injury, but rather lead to pain and injury over time. The major focus in low back pain is often the intervertebral disc, due to its role as the major primary load-bearing component along the spinal column. The formation of a reliable standard for human lumbar disc exposure to repeated transient shock could potentially reduce injury risk for these working populations. The objective of this project, therefore, is to characterize the mechanical response of the lumbar intervertebral disc subjected to sub-traumatic impact loading conditions using both cadaveric and computational models, and to investigate the possible implications of this type of loading environment for low back pain. Axial, compressive impact loading events on Naval high speed boats were simulated in the laboratory and applied to human cadaveric specimen. Disc stiffness was higher and hysteresis was lower than quasi-static loading conditions. This indicates a shift in mechanical response when the disc is under impact loads and this behavior could be contributing to long-term back pain. Interstitial fluid loss and disc height changes were shown to affect disc impact mechanics in a creep study. Neutral zone increased, while energy dissipation and low-strain region stiffness decreased. This suggests that the disc has greater clinical instability during impact loading with progressive creep and fluid loss, indicating that time of day should be considered for working populations subjected to impact loads. A finite element model was developed and validated against cadaver specimen

  8. Mitral valve repair for traumatic mitral regurgitation.

    PubMed

    Fujii, Taro; Kogure, Shuhei; Muro, Takashi; Okada, Yukikatsu

    2016-06-01

    Mitral valve injury after blunt chest trauma is a rare clinical condition. We describe a case of mitral valve repair for severe mitral regurgitation due to blunt chest trauma 5 years previously. A 22-year-old man was referred to our hospital for surgical correction of severe mitral regurgitation. Echocardiography demonstrated a partial tear of the anterolateral papillary muscle which lacerated to the apex. The entire anterolateral part of the mitral valve including the anterior commissure and posterior leaflets had prolapsed. Reimplantation of the papillary muscle to the posterior left ventricular wall and ring annuloplasty were successfully performed without residual regurgitation.

  9. Unusual redo mitral valve replacement for bleeding in Glanzmann thrombasthenia.

    PubMed

    Garcia-Villarreal, Ovidio A; Fernández-Ceseña, Ernesto; Solano-Ricardi, Mercedes; Aguilar-García, Alma L; Vega-Hernández, Raquel; Del Angel-Soto, Gustavo

    2016-01-01

    We report the case of 23-year-old man with mitral valve regurgitation and Glanzmann thrombasthenia, who underwent mechanical mitral valve replacement. Warfarin therapy was devastating, causing bilateral hemothorax, pericardial effusion, gastrointestinal bleeding, and hematuria. Redo mitral valve replacement with a biological prosthesis was required to resolve this critical situation. To our knowledge, this is the first report of mitral valve replacement in Glanzmann thrombasthenia, highlighting the danger of oral anticoagulation in this pathology.

  10. Modeling the Mitral Valve

    NASA Astrophysics Data System (ADS)

    Kaiser, Alexander

    2016-11-01

    The mitral valve is one of four valves in the human heart. The valve opens to allow oxygenated blood from the lungs to fill the left ventricle, and closes when the ventricle contracts to prevent backflow. The valve is composed of two fibrous leaflets which hang from a ring. These leaflets are supported like a parachute by a system of strings called chordae tendineae. In this talk, I will describe a new computational model of the mitral valve. To generate geometry, general information comes from classical anatomy texts and the author's dissection of porcine hearts. An MRI image of a human heart is used to locate the tips of the papillary muscles, which anchor the chordae tendineae, in relation to the mitral ring. The initial configurations of the valve leaflets and chordae tendineae are found by solving solving an equilibrium elasticity problem. The valve is then simulated in fluid (blood) using the immersed boundary method over multiple heart cycles in a model valve tester. We aim to identify features and mechanisms that influence or control valve function. Support from National Science Foundation, Graduate Research Fellowship Program, Grant DGE 1342536.

  11. Disc Degeneration Assessed by Quantitative T2* (T2 star) Correlated with Functional Lumbar Mechanics

    PubMed Central

    Ellingson, Arin M.; Mehta, Hitesh; Polly, David W.; Ellermann, Jutta; Nuckley, David J.

    2013-01-01

    Study Design Experimental correlation study design to quantify features of disc health, including signal intensity and distinction between the annulus fibrosus (AF) and nucleus pulposus (NP), with T2* magnetic resonance imaging (MRI) and correlate with the functional mechanics in corresponding motion segments. Objective Establish the relationship between disc health assessed by quantitative T2* MRI and functional lumbar mechanics. Summary of Background Data Degeneration leads to altered biochemistry in the disc, affecting the mechanical competence. Clinical routine MRI sequences are not adequate in detecting early changes in degeneration and fails to correlate with pain or improve patient stratification. Quantitative T2* relaxation time mapping probes biochemical features and may offer more sensitivity in assessing disc degeneration. Methods Cadaveric lumbar spines were imaged using quantitative T2* mapping, as well as conventional T2-weighted MRI sequences. Discs were graded by the Pfirrmann scale and features of disc health, including signal intensity (T2* Intensity Area) and distinction between the AF and NP (Transition Zone Slope), were quantified by T2*. Each motion segment was subjected to pure moment bending to determine range of motion (ROM), neutral zone (NZ), and bending stiffness. Results T2* Intensity Area and Transition Zone Slope were significantly correlated with flexion ROM (p=0.015; p=0.002), ratio of NZ/ROM (p=0.010; p=0.028), and stiffness (p=0.044; p=0.026), as well as lateral bending NZ/ROM (p=0.005; p=0.010) and stiffness (p=0.022; p=0.029). T2* Intensity Area was also correlated with LB ROM (p=0.023). Pfirrmann grade was only correlated with lateral bending NZ/ROM (p=0.001) and stiffness (p=0.007). Conclusions T2* mapping is a sensitive quantitative method capable of detecting changes associated with disc degeneration. Features of disc health quantified with T2* predicted altered functional mechanics of the lumbar spine better than

  12. Transcatheter mitral valve repair therapies for primary and secondary mitral regurgitation.

    PubMed

    Al Amri, Ibtihal; van der Kley, Frank; Schalij, Martin J; Ajmone Marsan, Nina; Delgado, Victoria

    2015-03-01

    Mitral regurgitation is one of the most prevalent valvular heart diseases and its prevalence is related to population aging. Elderly patients with age-associated co-morbidities have an increased risk for conventional mitral valve surgery. Transcatheter mitral valve repair has emerged as a feasible and safe alternative in patients with contraindications for surgery or high operative risk. Several transcatheter mitral repair technologies have been developed during the last decade. While the development of some devices was abandoned due to suboptimal results, others demonstrated to be safe and effective and have been included in current practice guidelines. Not all technologies are suitable for all mitral anatomies and regurgitation mechanisms. Therefore, accurate evaluation of mitral valve anatomy and function are pivotal to the success of these therapies. Cardiac imaging plays a central role in selecting patients, guiding the procedure and evaluating the durability of the repair at follow-up.

  13. Mechanical Vibrations Reduce the Intervertebral Disc Swelling and Muscle Atrophy from Bed Rest

    NASA Technical Reports Server (NTRS)

    Holguin, Nilsson; Muir, Jesse; Evans, Harlan J.; Qin, Yi-Xian; Rubin, Clinton; Wagshul, Mark; Judex, Stefan

    2007-01-01

    Loss of functional weight bearing, such as experienced during space flight or bed rest (BR), distorts intervertebral disc (IVD) and muscle morphology. IVDs are avascular structures consisting of cells that may derive their nutrition and waste removal from the load induced fluid flow into and out of the disc. A diurnal cycle is produced by forces related to weight bearing and muscular activity, and comprised of a supine and erect posture over a 24 hr period. A diurnal cycle will include a disc volume change of approx. 10-13%. However, in space there are little or no diurnal changes because of the microgravity, which removes the gravitational load and compressive forces to the back muscles. The BR model and the etiology of the disc swelling and muscle atrophy could provide insight into those subjects confined to bed for chronic disease/injury and aging. We hypothesize that extremely low-magnitude, high frequency mechanical vibrations will abate the disc degeneration and muscle loss associated with long-term BR.

  14. Drosophila wing imaginal discs respond to mechanical injury via slow InsP3R-mediated intercellular calcium waves

    NASA Astrophysics Data System (ADS)

    Restrepo, Simon; Basler, Konrad

    2016-08-01

    Calcium signalling is a highly versatile cellular communication system that modulates basic functions such as cell contractility, essential steps of animal development such as fertilization and higher-order processes such as memory. We probed the function of calcium signalling in Drosophila wing imaginal discs through a combination of ex vivo and in vivo imaging and genetic analysis. Here we discover that wing discs display slow, long-range intercellular calcium waves (ICWs) when mechanically stressed in vivo or cultured ex vivo. These slow imaginal disc intercellular calcium waves (SIDICs) are mediated by the inositol-3-phosphate receptor, the endoplasmic reticulum (ER) calcium pump SERCA and the key gap junction component Inx2. The knockdown of genes required for SIDIC formation and propagation negatively affects wing disc recovery after mechanical injury. Our results reveal a role for ICWs in wing disc homoeostasis and highlight the utility of the wing disc as a model for calcium signalling studies.

  15. Drosophila wing imaginal discs respond to mechanical injury via slow InsP3R-mediated intercellular calcium waves

    PubMed Central

    Restrepo, Simon; Basler, Konrad

    2016-01-01

    Calcium signalling is a highly versatile cellular communication system that modulates basic functions such as cell contractility, essential steps of animal development such as fertilization and higher-order processes such as memory. We probed the function of calcium signalling in Drosophila wing imaginal discs through a combination of ex vivo and in vivo imaging and genetic analysis. Here we discover that wing discs display slow, long-range intercellular calcium waves (ICWs) when mechanically stressed in vivo or cultured ex vivo. These slow imaginal disc intercellular calcium waves (SIDICs) are mediated by the inositol-3-phosphate receptor, the endoplasmic reticulum (ER) calcium pump SERCA and the key gap junction component Inx2. The knockdown of genes required for SIDIC formation and propagation negatively affects wing disc recovery after mechanical injury. Our results reveal a role for ICWs in wing disc homoeostasis and highlight the utility of the wing disc as a model for calcium signalling studies. PMID:27503836

  16. Mitral Valve Prolapse

    MedlinePlus

    Mitral valve prolapse (MVP) occurs when one of your heart's valves doesn't work properly. The flaps of ... Migraine headaches Chest discomfort Most people who have mitral valve prolapse (MVP) don't need treatment because they ...

  17. Left atrial mechanical functions in chronic primary mitral regurgitation patients: a velocity vector imaging-based study

    PubMed Central

    Yurdakul, Selen; Yıldirimtürk, Özlem

    2014-01-01

    Introduction Assessment of the left atrium (LA) mechanical function provides further information on the level of cardiac compensation. We aimed to evaluate LA function using a strain imaging method: velocity vector imaging (VVI) in chronic primary mitral regurgitation (MR). Material and methods We recruited 48 patients with chronic, isolated, moderate to severe MR (54.70 ±15.35 years and 56% male) and 30 age- and sex-matched healthy controls (56.52 ±15.95 years and 56% male). The LA volumes during reservoir (RV), conduit (CV) and contractile phases (AV) were measured. Global strain (S), systolic strain rate (SRs), early diastolic (ESRd) and late diastolic strain rate (LSRd) were calculated. Results LA RV (50 ±18.7 to 37.9 ±5.9; p = 0.0001), CV (43.1 ±29 to 21 ±2.56; p = 0.0001), and AV (17.9 ±13.5 to 10.9 ±1.9; p = 0.006) were increased in MR patients. The LA reservoir phase strain was 16.2 ±8.1% in the MR group and 51.1 ±5.7% in the control group (p = 0.0001). The LA SRs (1.01 ±0.52 s–1 for MR and 2.1 ±0.22 s–1 for controls; p = 0.0001), LA ESRd (0.83 ±0.34 s–1 for MR and 2.26 ±0.17 s–1 for controls; p = 0.0001) and LA LSRd (0.76 ±0.24 s–1 for MR and 2.2 ±0.26 s–1 for controls; p = 0.0001) were impaired in MR patients. Conclusions The LA deformation indices may be used as adjunctive parameters to determine LA dysfunction in chronic primary MR. PMID:25097574

  18. Mechanical testing and modelling of carbon-carbon composites for aircraft disc brakes

    NASA Astrophysics Data System (ADS)

    Bradley, Luke R.

    The objective of this study is to improve the understanding of the stress distributions and failure mechanisms experienced by carbon-carbon composite aircraft brake discs using finite element (FE) analyses. The project has been carried out in association with Dunlop Aerospace as an EPSRC CASE studentship. It therefore focuses on the carbon-carbon composite brake disc material produced by Dunlop Aerospace, although it is envisaged that the approach will have broader applications for modelling and mechanical testing of carbon-carbon composites in general. The disc brake material is a laminated carbon-carbon composite comprised of poly(acrylonitrile) (PAN) derived carbon fibres in a chemical vapour infiltration (CVI) deposited matrix, in which the reinforcement is present in both continuous fibre and chopped fibre forms. To pave the way for the finite element analysis, a comprehensive study of the mechanical properties of the carbon-carbon composite material was carried out. This focused largely, but not entirely, on model composite materials formulated using structural elements of the disc brake material. The strengths and moduli of these materials were measured in tension, compression and shear in several orientations. It was found that the stress-strain behaviour of the materials were linear in directions where there was some continuous fibre reinforcement, but non-linear when this was not the case. In all orientations, some degree of non-linearity was observed in the shear stress-strain response of the materials. However, this non-linearity was generally not large enough to pose a problem for the estimation of elastic moduli. Evidence was found for negative Poisson's ratio behaviour in some orientations of the material in tension. Additionally, the through-thickness properties of the composite, including interlaminar shear strength, were shown to be positively related to bulk density. The in-plane properties were mostly unrelated to bulk density over the range of

  19. Mitral Valve Prolapse

    PubMed Central

    Rosser, Walter W.

    1992-01-01

    The author discusses the pathophysiology of mitral valve prolapse and provides guidelines to identify and treat low-to high-risk mitral valve prolapse. An approach to diagnosing bacterial endocarditis and its prophylaxis are also discussed. The author reviews mitral valve prolapse syndrome and the risk of sudden death.

  20. Aurora on Uranus - A Faraday disc dynamo mechanism

    NASA Astrophysics Data System (ADS)

    Hill, T. W.; Dessler, A. J.; Rassbach, M. E.

    1983-10-01

    A mechanism is proposed whereby the solar wind flowing past the magnetosphere of Uranus causes a Faraday disk dynamo topology to be established and power to be extracted from the kinetic energy of rotation of Uranus. An immediate consequence of this dynamo is the generation of Birkeland currents that flow in and out of the sunlit polar cap with the accompanying production of polar aurora. The power extracted from planetary rotation is calculated as a function of planetary dipole magnetic moment and the ionospheric conductivity of Uranus. For plausible values of ionospheric conductivity, the observed auroral power requires a magnetic moment corresponding to a surface equatorial field of the order of 4 Gauss, slightly larger than the value 1.8 Gauss given by the empirical 'magnetic Bodes law'.

  1. The Impact of Fluid Inertia on In Vivo Estimation of Mitral Valve Leaflet Constitutive Properties and Mechanics.

    PubMed

    Bark, David L; Dasi, Lakshmi P

    2016-05-01

    We examine the influence of the added mass effect (fluid inertia) on mitral valve leaflet stress during isovolumetric phases. To study this effect, oscillating flow is applied to a flexible membrane at various frequencies to control inertia. Resulting membrane strain is calculated through a three-dimensional reconstruction of markers from stereo images. To investigate the effect in vivo, the analysis is repeated on a published dataset for an ovine mitral valve (Journal of Biomechanics 42(16): 2697-2701). The membrane experiment demonstrates that the relationship between pressure and strain must be corrected with a fluid inertia term if the ratio of inertia to pressure differential approaches 1. In the mitral valve, this ratio reaches 0.7 during isovolumetric contraction for an acceleration of 6 m/s(2). Acceleration is reduced by 72% during isovolumetric relaxation. Fluid acceleration also varies along the leaflet during isovolumetric phases, resulting in spatial variations in stress. These results demonstrate that fluid inertia may be the source of the temporally and spatially varying stiffness measurements previously seen through inverse finite element analysis of in vivo data during isovolumetric phases. This study demonstrates that there is a need to account for added mass effects when analyzing in vivo constitutive relationships of heart valves.

  2. Two-dimensional FSI simulation of closing dynamics of a tilting disc mechanical heart valve

    PubMed Central

    Govindarajan, V.; Udaykumar, H.S.; Herbertson, L. H.; Deutsch, S.; Manning, K. B.; Chandran, K.B.

    2010-01-01

    The fluid dynamics during valve closure resulting in high shear flows and large residence times of particles has been implicated in platelet activation and thrombus formation in mechanical heart valves. Our previous studies with bi-leaflet valves have shown that large shear stresses induced in the gap between the leaflet edge and the valve housing results in relatively high platelet activation levels whereas flow between the leaflets results in shed vortices not conducive to platelet damage. In this study we compare the result of closing dynamics of a tilting disc valve with that of a bi-leaflet valve. The two-dimensional fluid-structure interaction analysis of a tilting disc valve closure mechanics is performed with a fixed grid Cartesian mesh flow solver with local mesh refinement, and a Lagrangian particle dynamic analysis for computation of potential for platelet activation. Throughout the simulation the flow remains in the laminar regime and the flow through the gap width is marked by the development of a shear layer which separates from the leaflet downstream of the valve. Zones of re-circulation are observed in the gap between the leaflet edge and the valve housing on the major orifice region of the tilting disc valve and are seen to be migrating towards the minor orifice region. Jet flow is observed at the minor orifice region and a vortex is formed which sheds in the direction of fluid motion as observed in experiments using PIV measurements. The activation parameter computed for the tilting disc valve, at the time of closure was found to be 2.7 times greater than that of the bi-leaflet mechanical valve and was found to be in the vicinity of the minor orifice region mainly due to the migration of vortical structures from the major to the minor orifice region during the leaflet rebound of the closing phase. PMID:20209095

  3. An Unbiased Analysis of Candidate Mechanisms for the Regulation of Drosophila Wing Disc Growth

    PubMed Central

    Vollmer, Jannik; Iber, Dagmar

    2016-01-01

    The control of organ size presents a fundamental open problem in biology. A declining growth rate is observed in all studied higher animals, and the growth limiting mechanism may therefore be evolutionary conserved. Most studies of organ growth control have been carried out in Drosophila imaginal discs. We have previously shown that the area growth rate in the Drosophila eye primordium declines inversely proportional to the increase in its area, which is consistent with a dilution mechanism for growth control. Here, we show that a dilution mechanism cannot explain growth control in the Drosophila wing disc. We computationally evaluate a range of alternative candidate mechanisms and show that the experimental data can be best explained by a biphasic growth law. However, also logistic growth and an exponentially declining growth rate fit the data very well. The three growth laws correspond to fundamentally different growth mechanisms that we discuss. Since, as we show, a fit to the available experimental growth kinetics is insufficient to define the underlying mechanism of growth control, future experimental studies must focus on the molecular mechanisms to define the mechanism of growth control. PMID:27995964

  4. The three-dimension model for the rock-breaking mechanism of disc cutter and analysis of rock-breaking forces

    NASA Astrophysics Data System (ADS)

    Zhang, Zhao-Huang; Sun, Fei

    2012-06-01

    To study the rock deformation with three-dimensional model under rolling forces of disc cutter, by carrying out the circular-grooving test with disc cutter rolling around on the rock, the rock mechanical behavior under rolling disc cutter is studied, the mechanical model of disc cutter rolling around the groove is established, and the theory of single-point and double-angle variables is proposed. Based on this theory, the physics equations and geometric equations of rock mechanical behavior under disc cutters of tunnel boring machine (TBM) are studied, and then the balance equations of interactive forces between disc cutter and rock are established. Accordingly, formulas about normal force, rolling force and side force of a disc cutter are derived, and their validity is studied by tests. Therefore, a new method and theory is proposed to study rock-breaking mechanism of disc cutters.

  5. Mitral Valve Annuloplasty

    PubMed Central

    Rausch, Manuel K.; Bothe, Wolfgang; Kvitting, John-Peder Escobar; Swanson, Julia C.; Miller, D. Craig; Kuhl, Ellen

    2012-01-01

    Mitral valve annuloplasty is a common surgical technique used in the repair of a leaking valve by implanting an annuloplasty device. To enhance repair durability, these devices are designed to increase leaflet coaptation, while preserving the native annular shape and motion; however, the precise impact of device implantation on annular deformation, strain, and curvature is unknown. Here we quantify how three frequently used devices significantly impair native annular dynamics. In controlled in vivo experiments, we surgically implanted eleven flexible-incomplete, eleven semi-rigid-complete, and twelve rigid-complete devices around the mitral annuli of 34 sheep, each tagged with 16 equally-spaced tantalum markers. We recorded four-dimensional marker coordinates using biplane videofluoroscopy, first with device and then without, which were used to create mathematical models using piecewise cubic splines. Clinical metrics (characteristic anatomical distances) revealed significant global reduction in annular dynamics upon device implantation. Mechanical metrics (strain and curvature fields) explained this reduction via a local loss of anterior dilation and posterior contraction. Overall, all three devices unfavorably reduced annular dynamics. The flexible-incomplete device, however, preserved native annular dynamics to a larger extent than the complete devices. Heterogeneous strain and curvature profiles suggest the need for heterogeneous support, which may spawn more rational design of annuloplasty devices using design concepts of functionally graded materials. PMID:22037916

  6. Björk-Shiley strut fracture and disc escape: literature review and a method of disc retrieval.

    PubMed

    Hendel, P N

    1989-03-01

    Embolization of a prosthetic valve poppet is a rare but life-threatening event. It was reported sporadically before the introduction of the Björk-Shiley 70-degree convexoconcave prosthesis in 1980. Since that time, there have been a large number of reported mechanical failures with disc escape. The rate for the 29-mm to 33-mm mitral valves is estimated as 5.2%. In 29 of 35 patients (including the 2 presented here) in whom the site of disc lodgment could be determined, the disc was in the descending or abdominal aorta. Fifteen of these patients died. Six survivors had the disc removed at the same operation and 6 at a later operation. In 2 patients, the disc was not removed. In 2 patients in whom the disc was not removed initially, it was thought to contribute to postoperative complications. Two more cases of structural failure of the Björk-Shiley convexoconcave prosthesis are presented. A transpericardial approach to the descending aorta on bypass is described. It allows easy removal of the disc and eliminates the need for a second operation.

  7. Comparison of the occurrence of thromboembolic and bleeding complications in patients with mechanical heart valve prosthesis with one and two leaflets in the mitral position

    PubMed Central

    de Campos, Nelson Leonardo Kerdahi Leite

    2014-01-01

    Introduction Patients with mechanical heart valve prostheses must continuously be treated with oral anticoagulants to prevent thromboembolic events related to prosthetesis. These patients should be continually evaluated for the control of oral anticoagulation. Objective To compare the occurrence of thromboembolic and hemorragic complications in patients with mechanical heart valve prosthesis with one (mono) and two (bi) leaflets in the mitral position in anticoagulant therapy. Methods We studied the 10-year interval, 117 patients with prosthesis in the mitral position, 48 with prosthetic single leaflet and 69 with two leaflets. We evaluated the occurrence of thromboembolic and hemorrhagic major and minor degree under gravity. The results are presented in an actuarial study and the frequency of occurrence of linear events. Results The actuarial survival curves showed that over time, patients with prosthetic heart valve with one leaflet were less free of thromboembolic complications than patients with two leaflet prosthetic valve, while the latter (two leaflet) were less free of hemorrhagic accidents. The linearized frequency of occurrence of thromboembolism were higher in patients with mono leaflet prosthesis. Bleeding rates were higher for patients with bi leaflet prosthetic valve. Conclusion Patients with mono leaflet prosthetic heart valve showed that they are more prone to the occurrence of serious thromboembolic events compared to those with bi leaflet prosthetic valve. Patients with bi leaflet prosthetic valve had more bleeding than patients with mono leaflet prosthetic valve, however this difference was restricted to the bleeding of minor nature. PMID:24896164

  8. Mitral valve repair for ischemic mitral regurgitation.

    PubMed

    Mohebali, Jahan; Chen, Frederick Y

    2015-05-01

    Mitral valve repair for ischemic mitral valve regurgitation remains controversial. In moderate mitral regurgitation (MR), controversy exists whether revascularization alone will be adequate to restore native valve geometry or whether intervention on the valve (repair) should be performed concomitantly. When MR is severe, the need for valve intervention is not disputed. Rather, the controversy is whether repair versus replacement should be undertaken. In contrast to degenerative or myxomatous disease that directly affects leaflet integrity and morphology, ischemic FMR results from a distortion and dilation of native ventricular geometry that normally supports normal leaflet coaptation. To address this, the first and most crucial step in successful valve repair is placement of an undersized, complete remodeling annuloplasty ring to restore the annulus to its native geometry. The following article outlines the steps for repair of ischemic mitral regurgitation.

  9. Spatial and structural dependence of mechanical properties of porcine intervertebral disc.

    PubMed

    Causa, F; Manto, L; Borzacchiello, A; De Santis, R; Netti, P A; Ambrosio, L; Nicolais, L

    2002-12-01

    Structure-function relationship of natural tissues is crucial to design a device mimicking the structures present in human body. For this purpose, to provide guidelines to design an intervertebral disc (IVD) substitute, in this study the influence of the spatial location and structural components on the mechanical properties of porcine IVD was investigated. Local compressive stiffness (LCS) was measured on the overall disc, also constrained between the two adjacent vertebrae: the dependence on the lumbar position was evaluated. The compliance values in the anterior position (A) were higher than both in the central posterior (CP) and in the lateral-posterior (RP, LP) locations. The values of Young's Modulus (74.67+/-6.03 MPa) and compression break load (1.36x10(4)+/-0.09x10(4)N) of the disc were also evaluated by distributed compression test. The NP rheological behavior was typical of weak-gels, with elastic modulus G' always higher than viscous modulus G" all over the frequency range investigated (G' and G" respectively equal to 320 and 85 Pa at 1 Hz) and with the moduli trends were almost parallel to each other.

  10. Dynamics and mechanical stability of the developing dorsoventral organizer of the wing imaginal disc.

    PubMed

    Canela-Xandri, Oriol; Sagués, Francesc; Casademunt, Jaume; Buceta, Javier

    2011-09-01

    Shaping the primordia during development relies on forces and mechanisms able to control cell segregation. In the imaginal discs of Drosophila the cellular populations that will give rise to the dorsal and ventral parts on the wing blade are segregated and do not intermingle. A cellular population that becomes specified by the boundary of the dorsal and ventral cellular domains, the so-called organizer, controls this process. In this paper we study the dynamics and stability of the dorsal-ventral organizer of the wing imaginal disc of Drosophila as cell proliferation advances. Our approach is based on a vertex model to perform in silico experiments that are fully dynamical and take into account the available experimental data such as: cell packing properties, orientation of the cellular divisions, response upon membrane ablation, and robustness to mechanical perturbations induced by fast growing clones. Our results shed light on the complex interplay between the cytoskeleton mechanics, the cell cycle, the cell growth, and the cellular interactions in order to shape the dorsal-ventral organizer as a robust source of positional information and a lineage controller. Specifically, we elucidate the necessary and sufficient ingredients that enforce its functionality: distinctive mechanical properties, including increased tension, longer cell cycle duration, and a cleavage criterion that satisfies the Hertwig rule. Our results provide novel insights into the developmental mechanisms that drive the dynamics of the DV organizer and set a definition of the so-called Notch fence model in quantitative terms.

  11. [Modern mitral valve surgery].

    PubMed

    Bothe, W; Beyersdorf, F

    2016-04-01

    At the beginning of the 20th century, Cutler and Levine performed the first successful surgical treatment of a stenotic mitral valve, which was the only treatable heart valve defect at that time. Mitral valve surgery has evolved significantly since then. The introduction of the heart-lung machine in 1954 not only reduced the surgical risk, but also allowed the treatment of different mitral valve pathologies. Nowadays, mitral valve insufficiency has become the most common underlying pathomechanism of mitral valve disease and can be classified into primary and secondary mitral insufficiency. Primary mitral valve insufficiency is mainly caused by alterations of the valve (leaflets and primary order chords) itself, whereas left ventricular dilatation leading to papillary muscle displacement and leaflet tethering via second order chords is the main underlying pathomechanism for secondary mitral valve regurgitation. Valve reconstruction using the "loop technique" plus annuloplasty is the surgical strategy of choice and normalizes life expectancy in patients with primary mitral regurgitation. In patients with secondary mitral regurgitation, implanting an annuloplasty is not superior to valve replacement and results in high rates of valve re-insufficiency (up to 30 % after 3 months) due to ongoing ventricular dilatation. In order to improve repair results in these patients, we add a novel subvalvular technique (ring-noose-string) to the annuloplasty that aims to prevent ongoing ventricular remodeling and re-insufficiency. In modern mitral surgery, a right lateral thoracotomy is the approach of choice with excellent repair and cosmetic results.

  12. 1990 Volvo Award in experimental studies. The dependence of intervertebral disc mechanical properties on physiologic conditions.

    PubMed

    Keller, T S; Holm, S H; Hansson, T H; Spengler, D M

    1990-08-01

    In vivo creep-recovery and disc pressure measurements were performed on the lumbar spine of immature and mature swine. The creep-recovery measurements were performed using a custom materials testing apparatus designed to apply static or dynamic loads to the spine of anesthetized animals. A series of three separate experiments were performed to assess the effects of: (I) animal death, (II) graded injury to the disc anulus, and (III) respiratory mechanics on the biomechanical response of the porcine L1-L3 vertebral unit (VU). In Experiments I and II, creep rate, modulus, and viscosity parameters were computed using a three-parameter solid rheological analysis of the displacement-time response recorded during the application of a 300-N load. In Experiment III, the effects of respiratory volume and frequency changes on disc pressure were assessed in the unloaded, statically loaded, and immobilized porcine VU. Our results indicated that the adult VU tended to be stiffer, deform or creep more slowly, and had a significantly higher viscosity than the VU of immature pigs. The results of Experiment I demonstrated that the biomechanical response for the VU was significantly altered by the death of the animal; the VU of the living animal (adolescent or mature) was more compliant and deformed at a faster rate than the VU of the same animal after death. Disc injury produced changes in stiffness, viscosity, and creep rate analogous to that of aging, and on the basis of the graded injuries created in this study, it appears that a small defect in the annulus is just as deleterious as removing a large section of anular material. The results of Experiment III indicated that respiration plays an important role in the normal, in vivo mechanical and nutritional behavior of the porcine VU. Altogether, these results demonstrate that, in the absence of normal physiologic conditions, one may not be able to reliably predict the mechanical response of the lumbar spine, and suggest that

  13. Comparative Role of Disc Degeneration and Ligament Failure on Functional Mechanics of the Lumbar Spine

    PubMed Central

    Ellingson, Arin M.; Shaw, Miranda N.; Giambini, Hugo; An, Kai-Nan

    2015-01-01

    Understanding spinal kinematics is essential for distinguishing between pathological conditions of spine disorders, which ultimately lead to low back pain. It’s of high importance to understand how changes in mechanical properties affect the response of the lumbar spine, specifically in an effort to differentiate those associated with disc degeneration from ligamentous changes, allowing for more precise treatment strategies. To do this the goals of this study were twofold: 1) develop and validate a finite element (FE) model of the lumbar spine and 2) systematically alter the properties of the intervertebral disc and ligaments to define respective roles in functional mechanics. A three-dimensional non-linear FE model of the lumbar spine (L3-Sacrum) was developed and validated for pure moment bending. Disc degeneration and sequential ligament failure was modeled. Intersegmental range of motion (ROM) and bending stiffness was measured. The prediction of the FE model to moment loading in all three planes of bending showed very good agreement, where global and intersegmental ROM and bending stiffness of the model fell within one standard deviation of the in vitro results. Degeneration decreased ROM for all directions. Stiffness increased for all directions except axial rotation, where it initially increased then decreased for moderate and severe degeneration, respectively. Incremental ligament failure produced increased ROM and decreased stiffness. This effect was much more pronounced for all directions except lateral bending, which is minimally impacted by ligaments. These results indicate that lateral bending may be more apt to detect the subtle changes associated with degeneration, without being masked by associated changes of surrounding stabilizing structures. PMID:26404463

  14. Thermo-Mechanical Behaviour of Turbine Disc Assembly in the Presence of Residual Stresses

    NASA Astrophysics Data System (ADS)

    Maricic, Luke Anthony

    A comprehensive three dimensional coupled thermo-mechanical finite element study is performed on turbine blade attachments in gas turbine engines. The effects of the self-generated centrifugal forces of the disc and the associated blades, thermal loads, and shot peening residual are all considered in this thesis. Three aspects of the work were accordingly examined. The first was concerned with the coupled thermo-mechanical stress analysis and load sharing between the teeth of the fir-tree root. The second was devoted to the development of a complete model incorporating the effect of shot peening residual stresses upon the developed stress state. The effectiveness of shot peening treatment in response to cyclic thermo-mechanical loadings at the contact interface has also been studied. The third was concerned with the validation of some aspects of the developed models analytically using closed form solutions and experimentally using photoelasticity.

  15. Caseous Calcification of Mitral Annulus: A Rare Monster Leading to Cerebrovascular Accident.

    PubMed

    Memon, Sarfaraz; Chhabra, Lovely; Krainski, Felix; Parker, Matthew W; Swales, Heather

    2015-10-01

    Caseous calcification of the mitral annulus (CCMA) is a rare variant of mitral annular calcification that maybe easily misdiagnosed or confused with an abscess, a tumor, or infective vegetation. The main pathophysiological mechanism leading to CCMA involves degeneration and calcium deposition on the mitral valve. We present a case of CCMA to help understand this clinical entity.

  16. [Physiopathology of mitral mechanics in hypertrophic cardiomyopathy. Groupe de travail "Cardiomyopathies et insuffisance cardiaque" de la Société Française de Cardiologie].

    PubMed

    Hagège, A; Desnos, M; Komajda, M; Dubourg, O; Isnard, R; Guicheney, P; Schwartz, K; Lévine, R A

    1994-10-01

    Ventricular hypertrophy, the only indisputable phenotypical marker of hypertrophic cardiomyopathy, is the basis of the physiopathology and treatment of the disease. Mitral valve abnormalities are usually considered to be secondary to the hypertrophy but the genesis of systolic anterior motion by the Venturi effect has been questioned by many clinical and experimental observations. Abnormalities of the mitral valve apparatus may in themselves (elongation of the valves, antero-internal malposition of the mitral papillary muscles and/or hyperlaxicity of antero-internal corhdae tendinae) create systolic anterior motion or subaortic obstruction in the absence of septal hypertrophy and/or increased subaortic flow velocities. Anatomo-clinical studies have confirmed this hypothesis: a high prevalence of mitral valve disease (increased valvular surface and length) has been found in hypertrophic cardiomyopathy. The recognition of these abnormalities is of value from the therapeutic (mitral valvuloplasty) diagnostic (in borderline cases) and genetic (when the primary nature of the abnormalities is confirmed) points of view.

  17. Catalytic mechanism in cyclic voltammetry at disc electrodes: an analytical solution.

    PubMed

    Molina, Angela; González, Joaquín; Laborda, Eduardo; Wang, Yijun; Compton, Richard G

    2011-08-28

    The theory of cyclic voltammetry at disc electrodes and microelectrodes is developed for a system where the electroactive reactant is regenerated in solution using a catalyst. This catalytic process is of wide importance, not least in chemical sensing, and it can be characterized by the resulting peak current which is always larger than that of a simple electrochemical reaction; in contrast the reverse peak is always relatively diminished in size. From the theoretical point of view, the problem involves a complex physical situation with two-dimensional mass transport and non-uniform surface gradients. Because of this complexity, hitherto the treatment of this problem has been tackled mainly by means of numerical methods and so no analytical expression was available for the transient response of the catalytic mechanism in cyclic voltammetry when disc electrodes, the most popular practical geometry, are used. In this work, this gap is filled by presenting an analytical solution for the application of any sequence of potential pulses and, in particular, for cyclic voltammetry. The induction principle is applied to demonstrate mathematically that the superposition principle applies whatever the geometry of the electrode, which enabled us to obtain an analytical equation valid whatever the electrode size and the kinetics of the catalytic reaction. The theoretical results obtained are applied to the experimental study of the electrocatalytic Fenton reaction, determining the rate constant of the reduction of hydrogen peroxide by iron(II).

  18. Standard transthoracic echocardiography and transesophageal echocardiography views of mitral pathology that every surgeon should know

    PubMed Central

    Tan, Timothy C.

    2015-01-01

    The mitral valve is the most commonly diseased heart valve and the prevalence of mitral valve disease increases proportionally with age. Echocardiography is the primary diagnostic imaging modality used in the assessment of patients with mitral valve disease. It is a noninvasive method which provides accurate anatomic and functional information regarding the mitral valve and can identify the mechanism of mitral valve pathology. This is especially useful as it may guide surgical repair. This is increasingly relevant given the growing trend of patients undergoing mitral valve repair. Collaboration between cardiac surgeons and echocardiographers is critical in the evaluation of mitral valve disease and for identification of complex valvular lesions that require advanced surgical skill to repair. This article will provide an overview of transthoracic and transesophageal assessment of common mitral valve pathology that aims to aid surgical decision making. PMID:26539350

  19. Mitral Valve Prolapse

    MedlinePlus

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  20. Mitral Valve Prolapse.

    ERIC Educational Resources Information Center

    Bergy, Gordon G.

    1980-01-01

    Mitral valve prolapse is the most common heart disease seen in college and university health services. It underlies most arrhythmia and many chest complaints. Activity and exercise restrictions are usually unnecessary. (Author/CJ)

  1. Mitral Valve Disease

    MedlinePlus

    ... Heart Disease Diseases of the arteries, valves, and aorta, as well as cardiac rhythm disturbances Aortic Valve ... are two main types of mitral valve disease: Stenosis – the valve does not open enough to allow ...

  2. Role of vortices in cavitation formation in the flow at the closure of a bileaflet mitral mechanical heart valve.

    PubMed

    Li, Chi-Pei; Chen, Sheng-Fu; Lo, Chi-Wen; Lu, Po-Chien

    2012-03-01

    Bubble cavitation occurs in the flow field when local pressure drops below vapor pressure. One hypothesis states that low-pressure regions in vortices created by instantaneous valve closure and occluder rebound promote bubble formation. To quantitatively analyze the role of vortices in cavitation, we applied particle image velocimetry (PIV) to reduce the instantaneous fields into plane flow that contains information about vortex core radius, maximum tangential velocity, circulation strength, and pressure drop. Assuming symmetrical flow along the center of the St. Jude Medical 25-mm valve, flow fields downstream of the closing valve were measured using PIV in the mitral position of a circulatory mock loop. Flow measurements were made during successive time phases immediately following the impact of the occluder with the housing (O/H impact) at valve closing. The velocity profile near the vortex core clearly shows a typical Rankine vortex. The vortex strength reaches maximum immediately after closure and rapidly decreases at about 10 ms, indicating viscous dissipation; vortex strength also intensifies with rising pulse rate. The maximum pressure drop at the vortex center is approximately 20 mmHg, an insignificant drop relative to atmospheric vapor pressures, which implies vortices play a minor role in cavitation formation.

  3. Dynamic-mechanical properties of a novel composite intervertebral disc prosthesis.

    PubMed

    Gloria, Antonio; Causa, Filippo; De Santis, Roberto; Netti, Paolo Antonio; Ambrosio, Luigi

    2007-11-01

    Over the past years, a tremendous effort has been made to develop an intervertebral disc (IVD) prosthesis with suitable biological, mechanical and transport properties. However, it has been frequently reported that current prostheses undergo failure mainly due to the mismatch between the mechanical properties of the conventional device and the spine segment to be replaced. The aim of the present work was to develop a poly(2-hydroxyethyl methacrylate)/poly(methyl methacrylate) (PHEMA/PMMA) (80/20 w/w) semi-interpenetrating polymer network (s-IPN) composite hydrogel reinforced with poly(ethylene terephthalate) (PET) fibres, and to investigate the static and dynamic mechanical properties. Filament winding and moulding technologies were employed to obtain the composite IVD prostheses with the unique complex structure that is peculiar to the natural IVD. The compressive properties analysis showed the typical J-shaped stress-strain curve which is displayed by natural IVDs. Compressive modulus varied from 84 to 120 MPa, as a function of the strain rate, and stress was higher than 10 MPa. These values are in the range of those of the natural lumbar IVDs. No failure of the prostheses has occurred during fatigue test performed for ten million cycles in physiological solution. Dynamic mechanical tests have confirmed the composite IVD prostheses exhibited appropriate viscoelastic properties.

  4. Research on Heat-Mechanical Coupling of Ventilated Disc Brakes under the Condition of Emergency Braking

    NASA Astrophysics Data System (ADS)

    Tan, Xuelong; Zhang, Jian; Tang, Wenxian; Zhang, Yang

    Taking the ventilated disc brake in some company as research object, and using UG to build 3D models of brake disc and pad, and making use of ABAQUS/Standard to set up two parts' finite element model, via the decelerated motion of actual simulation brake disc, which gets ventilated disc brake in the case of emergency breaking in time and space distribution of conditions of temperature and stress field, summarizes the distribution of temperature field and stress field, proves complex coupling between temperature, stress, and supplies the direct basis for brake's fatigue life analysis.

  5. Mitral Valve Stenosis after Open Repair Surgery for Non-rheumatic Mitral Valve Regurgitation: A Review

    PubMed Central

    Shabsigh, Muhammad; Lawrence, Cassidy; Rosero-Britton, Byron R.; Kumar, Nicolas; Kimura, Satoshi; Durda, Michael Andrew; Essandoh, Michael

    2016-01-01

    Mitral stenosis (MS) after mitral valve (MV) repair is a slowly progressive condition, usually detected many years after the index MV surgery. It is defined as a mean transmitral pressure gradient (TMPG) >5 mmHg or a mitral valve area (MVA) <1.5 cm2. Pannus formation around the mitral annulus or extending to the mitral leaflets is suggested as the main mechanism for developing delayed MS after MV repair. On the other hand, early stenosis is thought to be a direct result of an undersized annuloplasty ring. Furthermore, in MS following ischemic mitral regurgitation (MR) repair, subvalvular tethering is the hypothesized pathophysiology. MS after MV repair has an incidence of 9–54%. Several factors have been associated with a higher risk for developing MS after MV repair, including the use of flexible Duran annuloplasty rings versus rigid Carpentier–Edwards rings, complete annuloplasty rings versus partial bands, small versus large anterior leaflet opening angle, and anterior leaflet tip opening length. Intraoperative echocardiography can measure the anterior leaflet opening angle, the anterior leaflet tip opening dimension, the MVA and the mean TMPG, and may help identify patients at risk for developing MS after MV repair. PMID:27148540

  6. Mitral Valve Stenosis after Open Repair Surgery for Non-rheumatic Mitral Valve Regurgitation: A Review.

    PubMed

    Shabsigh, Muhammad; Lawrence, Cassidy; Rosero-Britton, Byron R; Kumar, Nicolas; Kimura, Satoshi; Durda, Michael Andrew; Essandoh, Michael

    2016-01-01

    Mitral stenosis (MS) after mitral valve (MV) repair is a slowly progressive condition, usually detected many years after the index MV surgery. It is defined as a mean transmitral pressure gradient (TMPG) >5 mmHg or a mitral valve area (MVA) <1.5 cm(2). Pannus formation around the mitral annulus or extending to the mitral leaflets is suggested as the main mechanism for developing delayed MS after MV repair. On the other hand, early stenosis is thought to be a direct result of an undersized annuloplasty ring. Furthermore, in MS following ischemic mitral regurgitation (MR) repair, subvalvular tethering is the hypothesized pathophysiology. MS after MV repair has an incidence of 9-54%. Several factors have been associated with a higher risk for developing MS after MV repair, including the use of flexible Duran annuloplasty rings versus rigid Carpentier-Edwards rings, complete annuloplasty rings versus partial bands, small versus large anterior leaflet opening angle, and anterior leaflet tip opening length. Intraoperative echocardiography can measure the anterior leaflet opening angle, the anterior leaflet tip opening dimension, the MVA and the mean TMPG, and may help identify patients at risk for developing MS after MV repair.

  7. Percutaneous mitral valve repair for mitral regurgitation.

    PubMed

    Block, Peter C

    2003-02-01

    Mitral regurgitation (MR) associated with, ischemic, and degenerative (prolapse) disease, contributes to left ventricular (LV) dysfunction due to remodeling, and LV dilation, resulting in worsening of MR. Mitral valve (MV) surgical repair has provided improvement in survival, LV function and symptoms, especially when performed early. Surgical repair is complex, due to diverse etiologies and has significant complications. The Society for Thoracic Surgery database shows that operative mortality for a 1st repair is 2% and for re-do repair is 4 times that. Cardiopulmonary bypass and cardiac arrest are required. The attendant morbidity prolongs hospitalization and recovery. Alfieri simplified mitral repair using an edge-to-edge technique which subsequently has been shown to be effective for multiple etiologies of MR. The MV leaflers are typically brought together by a central suture producing a double orifice MV without stenosis. Umana reported that MR decreased from grade 3.6 +/- 0.5 to 0.8 +/- 0.4 (P < 0.0001) and LV ejection fraction increased from 33 +/- 13% to 45 +/- 11% (P = 0.0156). In 121 patients, Maisano reported freedom from re-operation of 95 +/- 4.8% with up to 6 year follow-up. Oz developed a MV "grasper" that is directly placed via a left ventriculotomy and coapts both leaflets which are then fastened by a graduated spiral screw. An in-vitro model using explanted human valves showed significant reduction in MR and in canine studies, animals followed by serial echo had persistent MV coaptation. At 12 weeks the device was endothelialized. These promising results have paved the way for a percutaneous or minimally invasive-off pump mitral repair. Evalve has developed catheter-based technology, which, by apposing the edges of a regurgitant MV, results in edge-to-edge repair. Release of the device is done after echo and fluoroscopic evaluation under normal loading conditions. If the desired effect is not produced the device can be repositioned or retrieved

  8. Strut fracture in the new Bjørk-Shiley mitral valve prosthesis.

    PubMed

    Brubakk, O; Simonsen, S; Källman, L; Fredriksen, A

    1981-04-01

    The case of a patient with the new type Bjørk-Shiley aortic and mitral valve prosthesis is described. Three months after implant she suffered acute heart failure and died. Post-mortem examination revealed a fractured outlet strut in the mitral valve prosthesis with dislocation of the disc. The fracture was regarded as due to excessive brittleness caused by demonstrated deposition of chromium-tungsten-carbide.

  9. A SECOND CASE OF LATE EMBOLIZATION OF PROSTHETIC MITRAL VALVE OCCLUDER WITH SURVIVAL FOLLOWING REOPERATION

    PubMed Central

    Sabbagh, Adib H.; O'Hare, James E.; Schocket, Lee I.; Pinckley, James N.

    1975-01-01

    A 51-year-old male with acute fulminating pulmonary edema and cardiogenic shock secondary to severe mitral insufficiency from dislodgment of the disc occluder in a Wada-Cutter valve was treated by immediate open heart procedure with a Bjork-Shiley mitral valve replacement. The patient survived and remains well. This is the second patient reported to survive operation and replacement of a malfunctioning prosthetic mitral valve from which the poppet escaped and embolized. The first case was reported by Hughes et al1 in February, 1975. Some striking similarities, as well as differences, in these two cases are discussed. Images PMID:15215920

  10. A SECOND CASE OF LATE EMBOLIZATION OF PROSTHETIC MITRAL VALVE OCCLUDER WITH SURVIVAL FOLLOWING REOPERATION.

    PubMed

    Sabbagh, Adib H.; O'Hare, James E.; Schocket, Lee I.; Pinckley, James N.

    1975-01-01

    A 51-year-old male with acute fulminating pulmonary edema and cardiogenic shock secondary to severe mitral insufficiency from dislodgment of the disc occluder in a Wada-Cutter valve was treated by immediate open heart procedure with a Bjork-Shiley mitral valve replacement. The patient survived and remains well. This is the second patient reported to survive operation and replacement of a malfunctioning prosthetic mitral valve from which the poppet escaped and embolized. The first case was reported by Hughes et al(1) in February, 1975. Some striking similarities, as well as differences, in these two cases are discussed.

  11. Abnormal Mitral Valve Dimensions in Pediatric Patients with Hypertrophic Cardiomyopathy.

    PubMed

    Schantz, Daryl; Benson, Lee; Windram, Jonathan; Wong, Derek; Dragulescu, Andreea; Yoo, Shi-Joon; Mertens, Luc; Friedberg, Mark; Al Nafisi, Bahiyah; Grosse-Wortmann, Lars

    2016-04-01

    The hearts of patients with hypertrophic cardiomyopathy (HCM) show structural abnormalities other than isolated wall thickening. Recently, adult HCM patients have been found to have longer mitral valve leaflets than control subjects. The aim of the current study was to assess whether children and adolescents with HCM have similar measureable differences in mitral valve leaflet dimensions when compared to a healthy control group. Clinical and echocardiographic data from 46 children with myocardial hypertrophy and a phenotype and/or genotype consistent with sarcomeric HCM were reviewed. Cardiac magnetic resonance imaging studies were evaluated. The anterior and posterior mitral valve leaflet lengths and myocardial structure were compared to 20 healthy controls. The anterior mitral valve was longer in the HCM group than in the control group (28.4 ± 4.9 vs. 25.2 ± 3.6 mm in control patients, p = 0.013) as was the posterior mitral valve leaflet (16.3 ± 3.0 vs. 13.1 ± 2.3 mm for controls <0.0001). There was no correlation between the resting left ventricular outflow tract gradient and anterior mitral valve leaflet length, nor was the anterior mitral valve leaflet longer in those with systolic anterior motion of the mitral valve compared to those without (28.9 ± 6.1 vs. 28.1 ± 4.5 mm, p = 0.61). Children and adolescents with HCM have abnormally long mitral valve leaflets when compared with healthy control subjects. These abnormalities do not appear to result in, or be due to, obstruction to left ventricular outflow. The mechanism of this mitral valve elongation is not clear but appears to be independent of hemodynamic disturbances.

  12. The challenges of managing rheumatic disease of the mitral valve in Jamaica.

    PubMed

    Little, Sherard G

    2014-12-01

    Between January, 2009 and December, 2013, 84 patients were identified who underwent isolated mitral valve surgery in Jamaica at The University Hospital of the West Indies and The Bustamante Hospital for Children. The most common pathology requiring surgery was rheumatic heart disease, accounting for 84% of the procedures performed. The majority of patients had regurgitation of the mitral valve (67%), stenosis of the mitral valve (22%), and mixed mitral valve disease (11%). The most common procedure performed was replacement of the mitral valve (69%), followed by mitral valve repair (29%). Among the patients, one underwent closed mitral commissurotomy. The choice of procedure differed between age groups. In the paediatric population (<18 years of age), the majority of patients underwent repair of the mitral valve (89%). In the adult population (18 years and above), the majority of patients underwent mitral valve replacement (93%). Overall, of all the patients undergoing replacement of the mitral valve, 89% received a mechanical valve prosthesis, whereas 11% received a bioprosthetic valve prosthesis. Of the group of patients who underwent mitral valve repair for rheumatic heart disease, 19% required re-operation. The average time between initial surgery and re-operation was 1.2 years. Rheumatic fever and rheumatic heart disease remain significant public health challenges in Jamaica and other developing countries. Focus must remain on primary and secondary prevention strategies in order to limit the burden of rheumatic valvulopathies. Attention should also be directed towards improving access to surgical treatment for young adults.

  13. Acute massive mitral regurgitation from prosthetic valve dysfunction.

    PubMed Central

    Cooper, D K; Sturridge, M F

    1976-01-01

    Two cases of prosthetic valve dysfunction resulting in acute massive mitral regurgitation are reported; emergency operation was successful in both cases. Survival following complete dislodgement of the occluder of a disc valve, as occurred in one case, does not appear to have been reported before. The diffculty in diagnosis of sudden cardiac decompensation in patients with prosthetic valves is stressed, as is the need for urgent operation. Images PMID:973894

  14. Mitral valve surgery - open

    MedlinePlus

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  15. On the mechanism of self gravitating Rossby interfacial waves in proto-stellar accretion discs

    NASA Astrophysics Data System (ADS)

    Yellin-Bergovoy, Ron; Heifetz, Eyal; Umurhan, Orkan M.

    2016-05-01

    The dynamical response of edge waves under the influence of self-gravity is examined in an idealized two-dimensional model of a proto-stellar disc, characterized in steady state as a rotating vertically infinite cylinder of fluid with constant density except for a single density interface at some radius r0. The fluid in basic state is prescribed to rotate with a Keplerian profile $\\Omega_k(r)\\sim r^{-3/2}$ modified by some additional azimuthal sheared flow. A linear analysis shows that there are two azimuthally propagating edge waves, kin to the familiar Rossby waves and surface gravity waves in terrestrial studies, which move opposite to one another with respect to the local basic state rotation rate at the interface. Instability only occurs if the radial pressure gradient is opposite to that of the density jump (unstably stratified) where self-gravity acts as a wave stabilizer irrespective of the stratification of the system. The propagation properties of the waves are discussed in detail in the language of vorticity edge waves. The roles of both Boussinesq and non-Boussinesq effects upon the stability and propagation of these waves with and without the inclusion of self-gravity are then quantified. The dynamics involved with self-gravity non- Boussinesq effect is shown to be a source of vorticity production where there is a jump in the basic state density, in addition, self-gravity also alters the dynamics via the radial main pressure gradient, which is a Boussinesq effect . Further applications of these mechanical insights are presented in the conclusion including the ways in which multiple density jumps or gaps may or may not be stable.

  16. How Is Mitral Valve Prolapse Treated?

    MedlinePlus

    ... page from the NHLBI on Twitter. How Is Mitral Valve Prolapse Treated? Most people who have mitral valve ... all hospitals offer this method. Valve Repair and Valve Replacement In mitral valve surgery, the valve is repaired or replaced. ...

  17. Exploring Regulatory Mechanisms of Atrial Myocyte Hypertrophy of Mitral Regurgitation through Gene Expression Profiling Analysis: Role of NFAT in Cardiac Hypertrophy

    PubMed Central

    Chang, Tzu-Hao; Chen, Mien-Cheng; Chang, Jen-Ping; Huang, Hsien-Da; Ho, Wan-Chun; Lin, Yu-Sheng; Pan, Kuo-Li; Huang, Yao-Kuang; Liu, Wen-Hao; Wu, Chia-Chen

    2016-01-01

    Background Left atrial enlargement in mitral regurgitation (MR) predicts a poor prognosis. The regulatory mechanisms of atrial myocyte hypertrophy of MR patients remain unknown. Methods and Results This study comprised 14 patients with MR, 7 patients with aortic valve disease (AVD), and 6 purchased samples from normal subjects (NC). We used microarrays, enrichment analysis and quantitative RT-PCR to study the gene expression profiles in the left atria. Microarray results showed that 112 genes were differentially up-regulated and 132 genes were differentially down-regulated in the left atria between MR patients and NC. Enrichment analysis of differentially expressed genes demonstrated that “NFAT in cardiac hypertrophy” pathway was not only one of the significant associated canonical pathways, but also the only one predicted with a non-zero score of 1.34 (i.e. activated) through Ingenuity Pathway Analysis molecule activity predictor. Ingenuity Pathway Analysis Global Molecular Network analysis exhibited that the highest score network also showed high association with cardiac related pathways and functions. Therefore, 5 NFAT associated genes (PPP3R1, PPP3CB, CAMK1, MEF2C, PLCE1) were studies for validation. The mRNA expressions of PPP3CB and MEF2C were significantly up-regulated, and CAMK1 and PPP3R1 were significantly down-regulated in MR patients compared to NC. Moreover, MR patients had significantly increased mRNA levels of PPP3CB, MEF2C and PLCE1 compared to AVD patients. The atrial myocyte size of MR patients significantly exceeded that of the AVD patients and NC. Conclusions Differentially expressed genes in the “NFAT in cardiac hypertrophy” pathway may play a critical role in the atrial myocyte hypertrophy of MR patients. PMID:27907007

  18. Diastolic Mitral Regurgitation in a Patient With Complex Native Mitral and Aortic Valve Endocarditis: A Rare Phenomenon With Potential Catastrophic Consequences.

    PubMed

    Pulido, Juan N; Lynch, James J; Mauermann, William J; Michelena, Hector I; Rehfeldt, Kent H

    2016-03-01

    Diastolic mitral valve regurgitation is a rare phenomenon described in patients with atrioventricular conduction abnormalities, severe left ventricular systolic or diastolic dysfunction with regional wall motion dyssynchrony, or severe acute aortic valve regurgitation. The presence of diastolic mitral valve regurgitation in acute aortic regurgitation due to endocarditis suggests critical severity requiring urgent surgical valve replacement. We describe a case of diastolic mitral regurgitation in the setting of complex native mitral-aortic valve endocarditis in a patient in normal sinus rhythm and review the etiologic mechanisms of this phenomenon, echocardiographic assessment, and therapeutic implications for hemodynamic management.

  19. Early Stabilization of Traumatic Aortic Transection and Mitral Valve Regurgitation

    PubMed Central

    Lambrechts, David L.; Wellens, Francis; Vercoutere, Rik A.; De Geest, Raf

    2003-01-01

    We report a case of life-threatening aortic transection with concomitant mitral papillary muscle rupture and severe lung contusion caused by a failed parachute jump. This blunt thoracic injury was treated by early stabilization with extracorporeal membrane oxygenation followed by successful delayed graft repair of the descending aorta and mitral valve replacement with a mechanical prosthesis. (Tex Heart Inst J 2003;30:65–7) PMID:12638675

  20. A pathoanatomic approach to the management of mitral regurgitation.

    PubMed

    Badhwar, Vinay; Smith, Anson J C; Cavalcante, João L

    2016-02-01

    Mitral regurgitation remains the most common global valvular heart disease. From otherwise unsuspecting healthy patients without overt symptoms to those with recalcitrant heart failure, mitral valve (MV) disease touches millions of patients per year. While MV prolapse without regurgitation remains benign, once regurgitation begins, quantification of severity is related to prognosis. Understanding the mechanism of regurgitation guides appropriate treatment. Current management guidelines emphasize early therapy after careful assessment of both anatomy and severity of mitral regurgitation. The objective of this review is to provide an update on the treatment of MV disease and to offer additional granularity on pathoanatomic decision making that may aid a more precise application of optimal guideline-directed therapy of primary and secondary mitral regurgitation.

  1. Severe mitral regurgitation unmasked after bilateral lung transplantation.

    PubMed

    Udoji, Timothy N; Force, Seth D; Pelaez, Andres

    2013-09-01

    Abstract A 33-year-old female patient with advanced idiopathic pulmonary artery hypertension underwent bilateral lung transplantation. The postsurgical course was complicated by prolonged mechanical ventilation and acute hypoxemia with recurrent episodes of pulmonary edema. An echocardiogram revealed improved right-sided pressures along with a dilated left atrium, a structurally normal mitral valve, and a new posterior-oriented severe mitral regurgitation. The patient's condition improved after treatment with arterial vasodilators and diuretics, and she has remained in World Health Organization functional class I after almost 36 months of follow-up. We hypothesize that cardiac ventricle remodeling and a geometric change in mitral valve apparatus after transplantation led to the hemodynamic changes and recurrent pulmonary edema seen in our patient. Our case is, to our knowledge, the second report of severe valvular regurgitation in a structurally normal mitral valve apparatus in the postoperative period and the first of a patient to be treated without valve replacement.

  2. Dissection of the atrial wall after mitral valve replacement.

    PubMed Central

    Lukács, L; Kassai, I; Lengyel, M

    1996-01-01

    We describe an unusual sequela of mitral valve replacement in a 50-year-old woman who had undergone a closed mitral commissurotomy in 1975. She was admitted to our hospital because of mitral restenosis in November 1993, at which time her mitral valve was replaced with a mechanical prosthesis. On the 8th postoperative day, the patient developed symptoms of heart failure; transesophageal echocardiography revealed dissection and rupture of the left atrial wall. At prompt reoperation, we found an interlayer dissection and rupture of the atrial wall into the left atrium. We repaired the ruptured atrial wall with a prosthetic patch. The postoperative course was uneventful, and postoperative transesophageal echocardiography showed normal prosthetic valve function and no dissection. Images PMID:8680278

  3. Effect of microstructure on high-temperature mechanical behavior of nickel-base superalloys for turbine disc applications

    NASA Astrophysics Data System (ADS)

    Sharpe, Heather Joan

    2007-05-01

    Engineers constantly seek advancements in the performance of aircraft and power generation engines, including, lower costs and emissions, and improved fuel efficiency. Nickel-base superalloys are the material of choice for turbine discs, which experience some of the highest temperatures and stresses in the engine. Engine performance is proportional to operating temperatures. Consequently, the high-temperature capabilities of disc materials limit the performance of gas-turbine engines. Therefore, any improvements to engine performance necessitate improved alloy performance. In order to take advantage of improvements in high-temperature capabilities through tailoring of alloy microstructure, the overall objectives of this work were to establish relationships between alloy processing and microstructure, and between microstructure and mechanical properties. In addition, the projected aimed to demonstrate the applicability of neural network modeling to the field of Ni-base disc alloy development and behavior. The first phase of this work addressed the issue of how microstructure varies with heat treatment and by what mechanisms these structures are formed. Further it considered how superalloy composition could account for microstructural variations from the same heat treatment. To study this, four next-generation Ni-base disc alloys were subjected to various controlled heat-treatments and the resulting microstructures were then quantified. These quantitative results were correlated to chemistry and processing, including solution temperature, cooling rate, and intermediate hold temperature. A complex interaction of processing steps and chemistry was found to contribute to all features measured; grain size, precipitate distribution, grain boundary serrations. Solution temperature, above a certain threshold, and cooling rate controlled grain size, while cooling rate and intermediate hold temperature controlled precipitate formation and grain boundary serrations. Diffusion

  4. The origin of thick discs

    NASA Astrophysics Data System (ADS)

    Comerón, Sébastien

    2015-03-01

    Thick discs are defined to be disc-like components with a scale height larger than that of the classical discs. They are ubiquitous (Yoachim & Dalcanton 2006; Comerón et al. 2011a), they are made of mostly old and metal-poor stars and are most easily detected in close to edge-on galaxies. Their origin has been considered mysterious and several formation theories have been proposed: • The thick disc being formed secularly by thin disc stars heated by disc overdensities such as giant molecular clouds or spiral arms (Villumsen 1985, ApJ, 290, 75) and by stars moved outwards from their original orbits by radial migration mechanisms (Schönrich & Binney 2009). • The thick disc being formed by the heating of the thin disc by satellites (Quinn et al. 1993) and the tidal stripping of them (Abadi et al. 2003). • The thick disc being formed fast and already thick at high redshift in an highly unstable disc. Inside that thick disc, a thin disc would form afterwards as suggested by Elemgreen & Elmegreen (2006). • The thick disc being formed originally thick at high redshift by the merger of gas-rich protogalactic fragments and a thin disc forming afterwards within it (Brook et al. 2007). The first mechanism is a secular evolution mechanism. The time-scale of the second one is dependent on the merger history of the main galaxy. In the two last mechanisms, the thick disc forms already thick in a short time-scale at high redshift. Recent Milky Way studies, (see, e.g., Bovy et al. 2012), have shown indications that there is no discontinuity between the thin and the thick disc chemical and kinematic properties. Instead, those studies indicate the presence of a monotonic distribution of disc thicknesses. This would suggest a secular origin for the Milky Way thick disc. Studies in external galaxies (Yoachim & Dalcanton 2006; Comerón et al. 2011b), have shown that low-mass disc galaxies have thick disc relative masses much larger than those found in large-mass galaxies

  5. Echocardiography in evaluation of mitral valve prostheses.

    PubMed

    Watts, E; Nomeir, A M; Barnes, R

    1975-06-01

    Thirty-three patients with mitral valve prostheses were studied with echocardiography in an effort to determine if this technique could be useful in detecting significant abnormalities. Recordings were obtained in the supine position with the transducer directed to record maximum excursion of the prosthesis. Echoes from the struts, poppet and sewing ring were readily recorded. Amplitude of excursion and opening and closing velocities of the poppet were measured. Fifty echocardiographic recordings were obtained from the 33 patients. Of the 33 patients studied, 22 were thought to have "normal" echo tracings while in 11, the tracings were considered "abnormal." Apparent abnormalities consisted of: 1) abnormal diastolic separation between the poppet and strut, 2) increased echoes near the poppet, strut or sewing ring and 3) a combination of both. There was only one instance of suspected "sticking" of the prosthesis. All patients who had "abnormal" studies except one developed complications associated with their prosthesis (90%) compared to only 36% in patients with "normal" tracings. Five patients in each group died. Autopsy studies are described and correlations with the echocardiographic findings are made. In low profile valves reduction in excursion of the disc may be an indication of malfunction. Echocardiography appears to be of value in the assessment of function of mitral valve prostheses.

  6. Lipomatous hamartoma of mitral valve.

    PubMed

    Bhat, Seetharama P S; Gowda, Girish S L; Chikkatur, Raghavendra; Nanjappa, Manjunath C

    2016-01-01

    Primary cardiac tumors are very rare, and tumors arising from cardiac valves are extremely rare. We present a case of lipomatous hamartoma of the mitral valve in a young female. This is the 6th case of lipomatous hamartoma of the mitral valve to be reported. We discuss the operative and histopathological findings.

  7. Fractured occluder disc: a previously unrecognized complication of the Starr-Edwards disc prosthesis.

    PubMed

    Malouf, J F; Hannoush, H M; Odell, J A

    2001-01-01

    Fracture of the occluder disc of a low-profile Starr-Edwards prosthesis is a hitherto unrecognized complication. We describe a patient who presented with right heart failure and severe pulmonary hypertension 27 years after mitral valve replacement with a model 6520 caged-disc prosthesis. At surgery, there was a longitudinal split in the occluder disc, and organized thrombus was lodged between the split segments. This case offers a unique opportunity to study the long-term effects of wear on the polyethylene poppet and Stellite cage.

  8. The use of a novel injectable hydrogel nucleus pulposus replacement in restoring the mechanical properties of cyclically fatigued porcine intervertebral discs.

    PubMed

    Balkovec, Christian; Vernengo, Jennifer; McGill, Stuart M

    2013-06-01

    Repeated flexion and extension of an intervertebral disc has been shown to affect the angular stiffness of spinal motion segments and is a barometer of the mechanical integrity of the disc. A degenerated disc that loses height causes higher levels of stress on the annulus and facet joints which may increase its level of degeneration; restoring disc height may therefore help to slow this degenerative cascade. Previous research has indicated that nucleus implants have the potential to improve the mechanical characteristics of a disc and an implant that is custom-fit to the intervertebral disc yields the best results with respect to decreasing annular degeneration. Two groups of porcine spinal motion segments were exposed to repeated flexion and extension. One group was then injected with a novel hydrogel while the other group was used as a control. Both groups were then exposed to another round of cyclic flexion and extension to examine the effect that the hydrogel had on restoring the original mechanics to the motion segments. Angular stiffness was restored to the group which received the hydrogel injection in addition to a significant improvement in specimen height. No significant changes were seen in the group which did not receive an injection. It would appear that use of the novel injectable hydrogel is able to restore angular stiffness to cyclically fatigued spinal motion segments. It is also important to note that continued repetition of the event causing specimen fatigue after performing hydrogel injection will result in an eventual return to the same fatigued state.

  9. Structure and mechanical function of the inter-lamellar matrix of the annulus fibrosus in the disc.

    PubMed

    Tavakoli, Javad; Elliott, Dawn M; Costi, John J

    2016-08-01

    The inter-lamellar matrix (ILM) has an average thickness of less than 30 µm and lies between adjacent lamellae in the annulus fibrosus (AF). The microstructure and composition of the ILM have been studied in various anatomic regions of the disc; however, their contribution to AF mechanical properties and structural integrity is unknown. It was suggested that the ILM components, mainly elastic fibers and cross-bridges, play a role in providing mechanical integrity of the AF. Therefore, the manner in which they respond to different loadings and stabilize adjacent lamellae structure will influence AF tear formation and subsequent herniation. This review paper summarizes the composition, microstructure, and potential role of the ILM in the progression of disc herniation, clarifies the micromechanical properties of the ILM, and proposes critical areas for future studies. There are a number of unknown characteristics of the ILM, such as its mechanical role, impact on AF integrity, and ultrastructure of elastic fibers at the ILM-lamella boundary. Determining these characteristics will provide important information for tissue engineering, repair strategies, and the development of more-physiological computational models to study the initiation and propagation of AF tears that lead to herniation and degeneration. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1307-1315, 2016.

  10. A global pattern of mechanical stress polarizes cell divisions and cell shape in the growing Drosophila wing disc.

    PubMed

    Legoff, Loïc; Rouault, Hervé; Lecuit, Thomas

    2013-10-01

    Organismal development is under genetic control. Ultimately, mechanical forces shape embryos. If we want to understand the precise regulation of size and shape in animals, we must dissect how forces are distributed in developing tissues, and how they drive cell behavior to shape organs. This has not been addressed fully in the context of growing tissues. As cells grow and divide, they exert a pressure on their neighbors. How these local stresses add up or dissipate as the tissue grows is an unanswered question. We address this issue in the growing wing imaginal disc of Drosophila larvae, the precursor of the adult wing. We used a quantitative approach to analyze the strains and stresses of cells of the wing pouch, and found a global pattern of stress whereby cells in the periphery of the tissue are mechanically stretched and cells in the center are compressed. This pattern has important consequences on cell shape in the wing pouch: cells respond to it by polarizing their acto-myosin cortex, and aligning their divisions with the main axis of cell stretch, thereby polarizing tissue growth. Ectopic perturbations of tissue growth by the Hippo signaling pathway reorganize this pattern in a non-autonomous manner, suggesting a synergy between tissue mechanics and growth control during wing disc morphogenesis.

  11. Floppy Mitral Valve (FMV) - Mitral Valve Prolapse (MVP) - Mitral Valvular Regurgitation and FMV/MVP Syndrome.

    PubMed

    Boudoulas, Konstantinos Dean; Pitsis, Antonios A; Boudoulas, Harisios

    2016-01-01

    Mitral valve prolapse (MVP) results from the systolic movement of a portion(s) or segment(s) of the mitral valve leaflet(s) into the left atrium during left ventricular (LV) systole. It should be emphasised that MVP alone, as defined by imaging techniques, may comprise a non-specific finding because it also depends on the LV volume, myocardial contractility and other LV hemodynamics. Thus, a floppy mitral valve (FMV) should be the basis for the diagnosis of MVP. Two types of symptoms may be defined in these patients. In one group, symptoms are directly related to progressive mitral regurgitation and its complications. In the other group, symptoms cannot be explained only by the degree of mitral regurgitation alone; neuroendocrine dysfunction has been implicated for the explanation of symptoms in this group of patients that today is referred as the FMV/MVP syndrome. When significant mitral regurgitation is present in a patient with FMV/MVP, surgical intervention is recommended. In patients with a prohibitive risk for surgery, transcatheter mitral valve repair using a mitraclip device may be considered. Furthermore, transcatheter mitral valve replacement may represent an option in the near future as clinical trials are underway. In this brief review, the current concepts related to FMV/MVP and FMV/MVP syndrome will be discussed.

  12. The Effect of a Variable Disc Pad Friction Coefficient for the Mechanical Brake System of a Railway Vehicle

    PubMed Central

    Lee, Nam-Jin; Kang, Chul-Goo

    2015-01-01

    A brake hardware-in-the-loop simulation (HILS) system for a railway vehicle is widely applied to estimate and validate braking performance in research studies and field tests. When we develop a simulation model for a full vehicle system, the characteristics of all components are generally properly simplified based on the understanding of each component’s purpose and interaction with other components. The friction coefficient between the brake disc and the pad used in simulations has been conventionally considered constant, and the effect of a variable friction coefficient is ignored with the assumption that the variability affects the performance of the vehicle braking very little. However, the friction coefficient of a disc pad changes significantly within a range due to environmental conditions, and thus, the friction coefficient can affect the performance of the brakes considerably, especially on the wheel slide. In this paper, we apply a variable friction coefficient and analyzed the effects of the variable friction coefficient on a mechanical brake system of a railway vehicle. We introduce a mathematical formula for the variable friction coefficient in which the variable friction is represented by two variables and five parameters. The proposed formula is applied to real-time simulations using a brake HILS system, and the effectiveness of the formula is verified experimentally by testing the mechanical braking performance of the brake HILS system. PMID:26267883

  13. The Effect of a Variable Disc Pad Friction Coefficient for the Mechanical Brake System of a Railway Vehicle.

    PubMed

    Lee, Nam-Jin; Kang, Chul-Goo

    2015-01-01

    A brake hardware-in-the-loop simulation (HILS) system for a railway vehicle is widely applied to estimate and validate braking performance in research studies and field tests. When we develop a simulation model for a full vehicle system, the characteristics of all components are generally properly simplified based on the understanding of each component's purpose and interaction with other components. The friction coefficient between the brake disc and the pad used in simulations has been conventionally considered constant, and the effect of a variable friction coefficient is ignored with the assumption that the variability affects the performance of the vehicle braking very little. However, the friction coefficient of a disc pad changes significantly within a range due to environmental conditions, and thus, the friction coefficient can affect the performance of the brakes considerably, especially on the wheel slide. In this paper, we apply a variable friction coefficient and analyzed the effects of the variable friction coefficient on a mechanical brake system of a railway vehicle. We introduce a mathematical formula for the variable friction coefficient in which the variable friction is represented by two variables and five parameters. The proposed formula is applied to real-time simulations using a brake HILS system, and the effectiveness of the formula is verified experimentally by testing the mechanical braking performance of the brake HILS system.

  14. Pathological mechanism of lumbar disc herniation resulting in neurogenic muscle hypertrophy.

    PubMed

    Walcott, Brian P; Nahed, Brian V; Redjal, Navid; Stein, Thor D; Kahle, Kristopher T; Coumans, Jean-Valery

    2011-12-01

    We present a 33-year-old man with 5-year history of low back pain who presented with an enlarging right calf. The patient underwent an extensive workup including biopsy without diagnosis. The patient's examination was significant for diminished pinprick sensation in the right L5/S1 dermatome. Reflexes were absent in the right ankle. The circumference of the right calf (58 cm) was twice that of the left. MRI revealed a herniated lumbar disc at the L5/S1 level. He then underwent a L5/S1 microdiscectomy. Following this surgery, the patient noted complete resolution of all sensory deficits in his lower extremity. His calf circumference had decreased by 5 cm at 4 months and by a total of 8 cm at his 2-year post-operative visit. Histological examination of the affected muscle demonstrated severe grouped atrophy of both type I and type II fibers. There was also evidence of compensatory fiber hypertrophy as well as fiber splitting. We concluded that the patient suffered from a herniated lumbar disc causing radiculopathy with calf hypertrophy (neurogenic hypertrophy). To our knowledge this is the first report of both grouped atrophy and compensatory hypertrophy of both muscle fiber types seen in this phenomenon.

  15. Early stabilization of traumatic aortic transection and mitral valve regurgitation with extracorporeal membrane oxygenation.

    PubMed

    Lambrechts, David L; Wellens, Francis; Vercoutere, Rik A; De Geest, Raf

    2003-01-01

    We report a case of life-threatening aortic transection with concomitant mitral papillary muscle rupture and severe lung contusion caused by a failed parachute jump. This blunt thoracic injury was treated by early stabilization with extracorporeal membrane oxygenation followed by successful delayed graft repair of the descending aorta and mitral valve replacement with a mechanical prosthesis.

  16. Evaluation of an In Situ Gelable and Injectable Hydrogel Treatment to Preserve Human Disc Mechanical Function Undergoing Physiologic Cyclic Loading Followed by Hydrated Recovery.

    PubMed

    Showalter, Brent L; Elliott, Dawn M; Chen, Weiliam; Malhotra, Neil R

    2015-08-01

    Despite the prevalence of disc degeneration and its contributions to low back problems, many current treatments are palliative only and ultimately fail. To address this, nucleus pulposus replacements are under development. Previous work on an injectable hydrogel nucleus pulposus replacement composed of n-carboxyethyl chitosan, oxidized dextran, and teleostean has shown that it has properties similar to native nucleus pulposus, can restore compressive range of motion in ovine discs, is biocompatible, and promotes cell proliferation. The objective of this study was to determine if the hydrogel implant will be contained and if it will restore mechanics in human discs undergoing physiologic cyclic compressive loading. Fourteen human lumbar spine segments were tested using physiologic cyclic compressive loading while intact, following nucleotomy, and again following treatment of injecting either phosphate buffered saline (PBS) (sham, n = 7) or hydrogel (implant, n = 7). In each compressive test, mechanical parameters were measured immediately before and after 10,000 cycles of compressive loading and following a period of hydrated recovery. The hydrogel implant was not ejected from the disc during 10,000 cycles of physiological compression testing and appeared undamaged when discs were bisected following all mechanical tests. For sham samples, creep during cyclic loading increased (+15%) from creep during nucleotomy testing, while for implant samples creep strain decreased (-3%) toward normal. There was no difference in compressive modulus or compressive strains between implant and sham samples. These findings demonstrate that the implant interdigitates with the nucleus pulposus, preventing its expulsion during 10,000 cycles of compressive loading and preserves disc creep within human L5-S1 discs. This and previous studies provide a solid foundation for continuing to evaluate the efficacy of the hydrogel implant.

  17. Percutaneous Transcatheter One-Step Mechanical Aortic Disc Valve Prosthesis Implantation: A Preliminary Feasibility Study in Swine

    SciTech Connect

    Sochman, Jan Peregrin, Jan H.; Rocek, Miloslav; Timmermans, Hans A.; Pavcnik, Dusan; Roesch, Josef

    2006-02-15

    Purpose. To evaluate the feasibility of one-step implantation of a new type of stent-based mechanical aortic disc valve prosthesis (MADVP) above and across the native aortic valve and its short-term function in swine with both functional and dysfunctional native valves. Methods. The MADVP consisted of a folding disc valve made of silicone elastomer attached to either a nitinol Z-stent (Z model) or a nitinol cross-braided stent (SX model). Implantation of 10 MADVPs (6 Z and 4 SX models) was attempted in 10 swine: 4 (2 Z and 2 SX models) with a functional native valve and 6 (4 Z and 2 SX models) with aortic regurgitation induced either by intentional valve injury or by MADVP placement across the native valve. MADVP function was observed for up to 3 hr after implantation. Results. MADVP implantation was successful in 9 swine. One animal died of induced massive regurgitation prior to implantation. Four MADVPs implanted above functioning native valves exhibited good function. In 5 swine with regurgitation, MADVP implantation corrected the induced native valve dysfunction and the device's continuous good function was observed in 4 animals. One MADVP (SX model) placed across native valve gradually migrated into the left ventricle. Conclusion. The tested MADVP can be implanted above and across the native valve in a one-step procedure and can replace the function of the regurgitating native valve. Further technical development and testing are warranted, preferably with a manufactured MADVP.

  18. Experimental study of the boiling mechanism of a liquid film flowing on the surface of a rotating disc

    SciTech Connect

    Kolokotsa, D.; Yanniotis, S.

    2010-11-15

    The boiling mechanism of a liquid film formed on the surface of a smooth horizontal rotating disc was studied using de-ionised water at 2 l/min flow rate, boiling under vacuum at 40 C and 5-10 C wall superheat. Visualization experiments were carried out and video films were taken for rotational speeds from 0 to 1000 rpm. It was observed that nucleate flow boiling prevails in the case of 0 rpm (stationary disc). Nucleate boiling was also observed at 100 and 200 rpm with the number of bubbles and the diameter of the bubbles decreasing as the rotational speed was increasing. At 600 and 1000 rpm rotational speeds, vapor bubbles were not observed. The results of visual observation were in agreement with bubble growth analysis which showed that at heat flux values of 40 kW/m{sup 2}, conditions for bubble growth are favorable at low rotational speeds (<200 rpm) but are unfavorable at high rotational speeds (1000 rpm). (author)

  19. The mechanism of disc pallor in experimental optic atrophy. A fluorescein angiographic study.

    PubMed

    Radius, R L; Anderson, D R

    1979-03-01

    Ascending optic atrophy was produced in 13 eyes of owl monkeys (Aotestrivirgatus) by retinal photocoagulation. Color fundus photography and fluorescein angiography were used to study and document the evolution of nerve head abnormalities. The optic nerve heads were also studied histopathologically. Except in certain instances of early transient (relative) filling defects, normal disc fluorescent patterns were preserved, despite clinically apparent optic nerve head pallor. Sectorial defects did not persist into the later phases of the angiogram. These findings may suggest a reduced blood flow, but neither angiographic nor histopathologic studies detected a reduced vascularity in the atrophic optic nerve. Pallor of the optic nerve head seems to result from alterations in the tissue reflectance and translucency following axonal loss and glial reorganization rather than from a decreased microvascular bed.

  20. Mitral Valve Prolapse (For Parents)

    MedlinePlus

    ... Atrial Septal Defect Ventricular Septal Defect Heart and Circulatory System Congenital Heart Defects Getting an EKG (Video) Your Heart & Circulatory System Heart Murmurs Marfan Syndrome Mitral Valve Prolapse EKG ( ...

  1. Mechanism enabling the observation of the formally optically-forbidden 2Ag- and 1Bu- states in resonance-Raman excitation profiles of spheroidene in KBr disc

    NASA Astrophysics Data System (ADS)

    Nagae, Hiroyoshi; Koyama, Yasushi

    2010-07-01

    An expression for the Albrecht A-term resonance-Raman excitation profiles (RREP) of a pigment dispersed in a KBr disc, in such a way that the pigment molecules aggregate in a microcrystal and the microcrystals are dispersed in the KBr disc, is formulated by taking into account the self-absorption of incident and scattered light and the distribution of microcrystals properly. Based on the resultant formula, simulations for the RREPs of spheroidene dispersed in KBr disc were carried out in the spectral region from 12,000 to 24,000 cm -1. Fairly good agreement between the simulations and the observed RREPs was obtained for different concentrations of spheroidene. Mechanisms have been investigated which enable the observation of the formally optically-forbidden (very weakly allowed) 2Ag- and 1Bu- states of spheroidne in RREPs free from the contribution of the optically-allowed 1Bu+ state, and a two-step self-absorption mechanism is proposed.

  2. Crystallization mechanisms and recording characteristics of Si/CuSi bilayer for write-once blu-ray disc

    NASA Astrophysics Data System (ADS)

    Ou, Sin-Liang; Kuo, Po-Cheng; Chen, Sheng-Chi; Tsai, Tsung-Lin; Yeh, Chin-Yen; Chang, Han-Feng; Lee, Chao-Te; Chiang, Donyau

    2011-09-01

    The crystallization mechanisms of Si/CuSi bilayer and its recording characteristics for write-once blu-ray disc (BD-R) were investigated. It was found that Cu3Si phase appeared during the room temperature sputtered deposition. Then, the Si atoms in CuSi layer segregated and crystallized to cubic Si in Cu3Si nucleation sites as the film was annealed at 270 °C. After heating to 500 °C, the grains size of cubic Si phase grew and the hexagonal Si phase was observed. The dynamic tests show that the Si/CuSi bilayer has great feasibility for 1-4× BD-R with the bottom jitter values below 6.5%.

  3. Simulated-physiological loading conditions preserve biological and mechanical properties of caprine lumbar intervertebral discs in ex vivo culture.

    PubMed

    Paul, Cornelis P L; Zuiderbaan, Hendrik A; Zandieh Doulabi, Behrouz; van der Veen, Albert J; van de Ven, Peter M; Smit, Theo H; Helder, Marco N; van Royen, Barend J; Mullender, Margriet G

    2012-01-01

    Low-back pain (LBP) is a common medical complaint and associated with high societal costs. Degeneration of the intervertebral disc (IVD) is assumed to be an important causal factor of LBP. IVDs are continuously mechanically loaded and both positive and negative effects have been attributed to different loading conditions.In order to study mechanical loading effects, degeneration-associated processes and/or potential regenerative therapies in IVDs, it is imperative to maintain the IVDs' structural integrity. While in vivo models provide comprehensive insight in IVD biology, an accompanying organ culture model can focus on a single factor, such as loading and may serve as a prescreening model to reduce life animal testing. In the current study we examined the feasibility of organ culture of caprine lumbar discs, with the hypothesis that a simulated-physiological load will optimally preserve IVD properties.Lumbar caprine IVDs (n = 175) were cultured in a bioreactor up to 21 days either without load, low dynamic load (LDL), or with simulated-physiological load (SPL). IVD stiffness was calculated from measurements of IVD loading and displacement. IVD nucleus, inner- and outer annulus were assessed for cell viability, cell density and gene expression. The extracellular matrix (ECM) was analyzed for water, glycosaminoglycan and total collagen content.IVD biomechanical properties did not change significantly with loading conditions. With SPL, cell viability, cell density and gene expression were preserved up to 21 days. Both unloaded and LDL resulted in decreased cell viability, cell density and significant changes in gene expression, yet no differences in ECM content were observed in any group.In conclusion, simulated-physiological loading preserved the native properties of caprine IVDs during a 21-day culture period. The characterization of caprine IVD response to culture in the LDCS under SPL conditions paves the way for controlled analysis of degeneration- and

  4. Patient-specific mitral leaflet segmentation from 4D ultrasound.

    PubMed

    Schneider, Robert J; Tenenholtz, Neil A; Perrin, Douglas P; Marx, Gerald R; del Nido, Pedro J; Howe, Robert D

    2011-01-01

    Segmenting the mitral valve during closure and throughout a cardiac cycle from four dimensional ultrasound (4DUS) is important for creation and validation of mechanical models and for improved visualization and understanding of mitral valve behavior. Current methods of segmenting the valve from 4DUS either require extensive user interaction and initialization, do not maintain the valve geometry across a cardiac cycle, or are incapable of producing a detailed coaptation line and surface. We present a method of segmenting the mitral valve annulus and leaflets from 4DUS such that a detailed, patient-specific annulus and leaflets are tracked throughout mitral valve closure, resulting in a detailed coaptation region. The method requires only the selection of two frames from a sequence indicating the start and end of valve closure and a single point near a closed valve. The annulus and leaflets are first found through direct segmentation in the appropriate frames and then by tracking the known geometry to the remaining frames. We compared the automatically segmented meshes to expert manual tracings for both a normal and diseased mitral valve, and found an average difference of 0.59 +/- 0.49 mm, which is on the order of the spatial resolution of the ultrasound volumes (0.5-1.0 mm/voxel).

  5. Genetic association analyses highlight biological pathways underlying mitral valve prolapse.

    PubMed

    Dina, Christian; Bouatia-Naji, Nabila; Tucker, Nathan; Delling, Francesca N; Toomer, Katelynn; Durst, Ronen; Perrocheau, Maelle; Fernandez-Friera, Leticia; Solis, Jorge; Le Tourneau, Thierry; Chen, Ming-Huei; Probst, Vincent; Bosse, Yohan; Pibarot, Philippe; Zelenika, Diana; Lathrop, Mark; Hercberg, Serge; Roussel, Ronan; Benjamin, Emelia J; Bonnet, Fabrice; Lo, Su Hao; Dolmatova, Elena; Simonet, Floriane; Lecointe, Simon; Kyndt, Florence; Redon, Richard; Le Marec, Hervé; Froguel, Philippe; Ellinor, Patrick T; Vasan, Ramachandran S; Bruneval, Patrick; Markwald, Roger R; Norris, Russell A; Milan, David J; Slaugenhaupt, Susan A; Levine, Robert A; Schott, Jean-Jacques; Hagege, Albert A; Jeunemaitre, Xavier

    2015-10-01

    Nonsyndromic mitral valve prolapse (MVP) is a common degenerative cardiac valvulopathy of unknown etiology that predisposes to mitral regurgitation, heart failure and sudden death. Previous family and pathophysiological studies suggest a complex pattern of inheritance. We performed a meta-analysis of 2 genome-wide association studies in 1,412 MVP cases and 2,439 controls. We identified 6 loci, which we replicated in 1,422 cases and 6,779 controls, and provide functional evidence for candidate genes. We highlight LMCD1 (LIM and cysteine-rich domains 1), which encodes a transcription factor and for which morpholino knockdown of the ortholog in zebrafish resulted in atrioventricular valve regurgitation. A similar zebrafish phenotype was obtained with knockdown of the ortholog of TNS1, which encodes tensin 1, a focal adhesion protein involved in cytoskeleton organization. We also showed expression of tensin 1 during valve morphogenesis and describe enlarged posterior mitral leaflets in Tns1(-/-) mice. This study identifies the first risk loci for MVP and suggests new mechanisms involved in mitral valve regurgitation, the most common indication for mitral valve repair.

  6. Genetic association analyses highlight biological pathways underlying mitral valve prolapse

    PubMed Central

    Dina, Christian; Bouatia-Naji, Nabila; Tucker, Nathan; Delling, Francesca N.; Toomer, Katelynn; Durst, Ronen; Perrocheau, Maelle; Fernandez-Friera, Leticia; Solis, Jorge; Le Tourneau, Thierry; Chen, Ming-Huei; Probst, Vincent; Bosse, Yohan; Pibarot, Philippe; Zelenika, Diana; Lathrop, Mark; Hercberg, Serge; Roussel, Ronan; Benjamin, Emelia J.; Bonnet, Fabrice; Su Hao, LO; Dolmatova, Elena; Simonet, Floriane; Lecointe, Simon; Kyndt, Florence; Redon, Richard; Le Marec, Hervé; Froguel, Philippe; Ellinor, Patrick T.; Vasan, Ramachandran S.; Bruneval, Patrick; Norris, Russell A.; Milan, David J.; Slaugenhaupt, Susan A.; Levine, Robert A.; Schott, Jean-Jacques; Hagege, Albert A.; Jeunemaitre, Xavier

    2016-01-01

    Non-syndromic mitral valve prolapse (MVP) is a common degenerative cardiac valvulopathy of unknown aetiology that predisposes to mitral regurgitation, heart failure and sudden death1. Previous family and pathophysiological studies suggest a complex pattern of inheritance2–5. We performed a meta-analysis of two genome-wide association studies in 1,442 cases and 2,439 controls. We identified and replicated in 1,422 cases and 6,779 controls six loci and provide functional evidence for candidate genes. We highlight LMCD1 encoding a transcription factor6, for which morpholino knockdown in zebrafish results in atrioventricular (AV) valve regurgitation. A similar zebrafish phenotype was obtained for tensin1 (TNS1), a focal adhesion protein involved in cytoskeleton organization. We also show the expression of tensin1 during valve morphogenesis and describe enlarged posterior mitral leaflets in Tns1−/− mice. This study identifies the first risk loci for MVP and suggests new mechanisms involved in mitral valve regurgitation, the most common indication for mitral valve repair7. PMID:26301497

  7. Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra

    ClinicalTrials.gov

    2016-03-09

    Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

  8. Mitral valve regurgitation due to annular dilatation caused by a huge and floating left atrial myxoma

    PubMed Central

    Ersoy, Burak; Yeniterzi, Mehmet

    2015-01-01

    We describe a case of mitral valve annular dilatation caused by a huge left atrial myxoma obstructing the mitral valve orifice. A 50-year-old man presenting with palpitation was found to have a huge left atrial myxoma protruding into the left ventricle during diastole, causing severe mitral regurgitation. The diagnosis was made with echocardiogram. Transoesophageal echocardiography revealed a solid mass of 75 × 55 mm. During operation, the myxoma was completely removed from its attachment in the atrium. We preferred to place a mechanical heart valve after an annuloplasty ring because of severely dilated mitral annulus and chordae elongation. The patient had an uneventful recovery. Our case suggests that immediate surgery, careful evaluation of mitral valve annulus preoperatively is recommended. PMID:26702283

  9. Severe hemolytic anemia after repair of primum septal defect and cleft mitral valve.

    PubMed

    Alehan, D; Doğan, R; Ozkutlu, S; Elshershari, H; Gümrük, F

    2001-01-01

    Two cases are described in which severe mechanical hemolytic anemia developed after surgical repair of primum atrial septal defect (ASD) and cleft mitral valve. In both cases there was residual mitral regurgitation after repair. Moderate mitral regurgitation and collision of the regurgitant jet with the teflon patch used for repair of the primum ASD were detected by color-Doppler echocardiography imaging. Laboratory tests showed normochromic normocytic anemia, increased indirect serum bilirubin, decreased plasma haptoglobin and hemoglobinuria. The peripheral blood smear contained numerous fragmented red cells. Following another surgical correction of the mitral valve (repair or mitral valve replacement), there was no more hemolysis. The two presented cases show that foreign materials in association with localized intracardiac turbulence may cause severe hemolysis.

  10. The elastic fibre network of the human lumbar anulus fibrosus: architecture, mechanical function and potential role in the progression of intervertebral disc degeneration

    PubMed Central

    Fazzalari, Nicola L.

    2009-01-01

    Elastic fibres are critical constituents of dynamic biological structures that functionally require elasticity and resilience. The network of elastic fibres in the anulus fibrosus of the intervertebral disc is extensive, however until recently, the majority of histological, biochemical and biomechanical studies have focussed on the roles of other extracellular matrix constituents such as collagens and proteoglycans. The resulting lack of detailed descriptions of elastic fibre network architecture and mechanical function has limited understanding of the potentially important contribution made by elastic fibres to healthy disc function and their possible roles in the progression of disc degeneration. In addition, it has made it difficult to postulate what the consequences of elastic fibre related disorders would be for intervertebral disc behaviour, and to develop treatments accordingly. In this paper, we review recent and historical studies which have examined both the structure and the function of the human lumbar anulus fibrosus elastic fibre network, provide a synergistic discussion in an attempt to clarify its potentially critical contribution both to normal intervertebral disc behaviour and the processes relating to its degeneration, and recommend critical areas for future research. PMID:19263091

  11. Noninvasive diagnostic evaluation of the normal Beall mitral prosthesis.

    PubMed

    Smith, R A; Kerber, R E; Snyder, J W

    1976-01-01

    Phonocardiography and echocardiography were used to examine 20 patients with a normally functioning Beall disc mitral valve prosthesis. Phonocardiographic intervals were: Q-S1 interval 67 +/- 3 msec; A2-OC interval 118 +/- 8 msec. Maximal variation of the Q-S1 interval within one examination was 21 +/- 2 msec, for A2-OC interval it was 31 +/- 5 msec. Echocardiographic disc velocities were: opening velocity 296 +/- 30 mm/sec, closing velocity 414 +/- 44 mm/sec. Maximal variation of the opening velocity was 126 +/- 25 msec; maximal variation of the closing velocity was 334 +/- 57 msec. Abnormal poppet function was suspected in one patient with unusual prolongation and variability of A2-OC interval.

  12. [Mitral valve repair with the MitraClip following surgical mitral annuloplasty failure].

    PubMed

    Picard, F; Tadros, V-X; Millán, X; Asgar, A W

    2016-10-28

    Mitral repair using the MitraClip device is on ongoing expansion and has been evaluated in different patterns of mitral regurgitation. Nevertheless, surgical approaches to mitral regurgitation remain the standard of care, at least in absence of contraindication. We report the first Canadian experience of mitral valve repair with the MitraClip following surgical mitral annuloplasty failure. Therapeutic considerations and potential challenges are discussed.

  13. Minimally Invasive Mitral Valve Surgery II

    PubMed Central

    Wolfe, J. Alan; Malaisrie, S. Chris; Farivar, R. Saeid; Khan, Junaid H.; Hargrove, W. Clark; Moront, Michael G.; Ryan, William H.; Ailawadi, Gorav; Agnihotri, Arvind K.; Hummel, Brian W.; Fayers, Trevor M.; Grossi, Eugene A.; Guy, T. Sloane; Lehr, Eric J.; Mehall, John R.; Murphy, Douglas A.; Rodriguez, Evelio; Salemi, Arash; Segurola, Romualdo J.; Shemin, Richard J.; Smith, J. Michael; Smith, Robert L.; Weldner, Paul W.; Lewis, Clifton T. P.; Barnhart, Glenn R.; Goldman, Scott M.

    2016-01-01

    Abstract Techniques for minimally invasive mitral valve repair and replacement continue to evolve. This expert opinion, the second of a 3-part series, outlines current best practices for nonrobotic, minimally invasive mitral valve procedures, and for postoperative care after minimally invasive mitral valve surgery. PMID:27654406

  14. Durability of mitral valve repair for mitral regurgitation due to degenerative mitral valve disease.

    PubMed

    David, Tirone E

    2015-09-01

    Degenerative diseases of the mitral valve (MV) are the most common cause of mitral regurgitation in the Western world and the most suitable pathology for MV repair. Several studies have shown excellent long-term durability of MV repair for degenerative diseases. The best follow-up results are obtained with isolated prolapse of the posterior leaflet, however even with isolated prolapse of the anterior leaflet or prolapse of both leaflets the results are gratifying, particularly in young patients. The freedom from reoperation on the MV at 15 years exceeds 90% for isolated prolapse of the posterior leaflet and it is around 70-85% for prolapse of the anterior leaflet or both leaflets. The degree of degenerative change in the MV also plays a role in durability of MV repair. Most studies have used freedom from reoperation to assess durability of the repair but some studies that examined valve function late after surgery suggest that recurrent mitral regurgitation is higher than estimated by freedom from reoperation. We can conclude that MV repair for degenerative mitral regurgitation is associated with low probability of reoperation for up to two decades after surgery. However, almost one-third of the patients develop recurrent moderate or severe mitral regurgitation suggesting that surgery does not arrest the degenerative process.

  15. Recent developments in percutaneous mitral valve treatment.

    PubMed

    La Canna, Giovanni; Denti, Paolo; Buzzatti, Nicola; Alfieri, Ottavio

    2016-01-01

    In recent years, various percutaneous techniques have been introduced for the treatment of mitral regurgitation (MR), including direct leaflet repair, annuloplasty and left ventricular remodeling. Percutaneous mitral repair targets both primary degenerative and secondary mitral valve regurgitation and may be considered in selected high-surgical-risk patients. The assessment of mitral functional anatomy by echocardiography and computed tomography is crucial when selecting the appropriate repair strategy, according to the regurgitant valve lesion and the surrounding anatomy. The ongoing clinical use of new devices in annuloplasty and percutaneous mitral valve replacement is a promising new scenario in the treatment of MR that goes beyond the conventional surgical approach.

  16. Rare Case of Unileaflet Mitral Valve.

    PubMed

    Shah, Jainil; Jain, Tarun; Shah, Sunay; Mawri, Sagger; Ananthasubramaniam, Karthikeyan

    2016-06-01

    Unileaflet mitral valve is the rarest of the congenital mitral valve anomalies and is usually life threatening in infancy due to severe mitral regurgitation (MR). In most asymptomatic individuals, it is mostly due to hypoplastic posterior mitral leaflet. We present a 22-year-old male with palpitations, who was found to have an echocardiogram revealing an elongated anterior mitral valve leaflet with severely hypoplastic posterior mitral valve leaflet appearing as a unileaflet mitral valve without MR. Our case is one of the 11 reported cases in the literature so far. We hereby review those cases and conclude that these patients are likely to be at risk of developing worsening MR later in their lives.

  17. The high-throughput phenotyping of the viscoelastic behavior of whole mouse intervertebral discs using a novel method of dynamic mechanical testing.

    PubMed

    Liu, Jennifer W; Abraham, Adam C; Tang, Simon Y

    2015-07-16

    Intervertebral disc (IVD) degeneration is highly correlated with lower back pain, and thus understanding the mechanisms of IVD degeneration is critical for the treatment of this disease. Utilizing mouse models to probe the mechanisms of degeneration is especially attractive due to the ease of manipulating mouse models and the availability of transgenics. Yet characterizing the mechanical behavior of mice IVDs remain challenging due to their minute size (approximately 540 μm in height and 1080 μm(2) in cross sectional area). We have thus developed a simple method to dynamically characterize the mechanical properties of intact mouse IVDs. The IVDs were dissected with the endplates intact, and dynamically compressed in the axial direction at 1% and 5% peak strains at 1 Hz. Utilizing this novel approach, we examined the effects of in vitro ribosylation and trypsin digestion for 24 or 72 h on the viscoelastic behavior of the whole murine IVD. Trypsin treatment resulted in a decrease of proteoglycans and loss of disc height, while ribosylation had no effect on structure or proteoglycan composition. The 72 h ribosylation group exhibited a stiffening of the disc, and both treatments significantly reduced viscous behavior of the IVDs, with the effects being more pronounced at 5% strain. Here we demonstrate a novel high-throughput method to mechanically characterize murine IVDs and detect strain-dependent differences in the elastic and the viscous behavior of the treated IVDs due to ribose and trypsin treatments.

  18. Mitral valve surgery - minimally invasive

    MedlinePlus

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  19. Effect of different light curing methods on mechanical and physical properties of resin-cements polymerized through ceramic discs

    PubMed Central

    CEKIC-NAGAS, Isil; ERGUN, Gulfem

    2011-01-01

    Objective The aim of this study was to compare the polimerization ability of three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) and their exposure modes (high-intensity and soft-start) by determination of microhardness, water sorption and solubility, and diametral tensile strength of 5 dual-curing resin cements. Material and methods A total of 720 disc-shaped samples (1 mm height and 5 mm diameter) were prepared from different dual-curing resin cements (Duolink, Nexus, Bifix-QM, Panavia F and RelyX Unicem). Photoactivation was performed by using quartz tungsten halogen (high-power and soft-up modes), light-emitting diode (standard and exponential modes) and plasma arc (normal and ramp-curing modes) curing units through ceramic discs. Then the samples (n=8/per group) were stored dry in the dark at 37ºC for 24 h. The Vickers hardness test was performed on the resin cement layer with a microhardness tester (Shimadzu HMV). For sorption and solubility tests; the samples were stored in a desiccator at 37ºC and weighed to a constant mass. The samples were weighed both before and after being immersed in deionized water for different periods of time (24 h and 7 days) and being desiccated. The diametral tensile strength of the samples was tested in a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by nonparametric Kruskal Wallis and Mann-Whitney U tests at 5% significance level. Results Resin cement and light-curing unit had significant effects (p<0.05) on microhardness, diametral tensile strength, water solubility and sorption. However, no significant differences (p>0.05) were obtained with different modes of LCUs. Conclusion The study indicates that polymerization of resin cements with different light-curing units may result in various polymer structures, and consequently different mechanical and physical properties. PMID:21710093

  20. Velocity of closure of Björk-Shiley Convexo-Concave mitral valves: effect of mitral annulus orientation and rate of left ventricular pressure rise.

    PubMed

    Blick, E F; Wieting, D W; Inderbitzen, R; Schreck, S; Stein, P D

    1995-07-01

    The purpose of this study was to determine analytically the hemodynamic factors that affect the closing velocity of the disc of Björk-Shiley convexo-concave (BSCC) prosthetic mitral valves. The motion of the BSCC disk was modelled by Newton's second law written in the form of a second order differential equation which expressed the instantaneous angle of the disc with respect to the valve ring as a function of the instantaneous pressure drop across the mitral valve, delta P(t), and the angle of the pressure gradient vector acting upon the disc during closure. The disc closes in response to the negative pressure drop created by the crossover of left atrial and left ventricular (LV) pressures. The rate of closure depends on the rate of development of the pressure drop across the valve, d delta P/dt, which is largely dependent upon the rate of change of left ventricular pressure during isovolumic contraction, LV dP/dt. The closure rate is also strongly dependent on the initial angle of the pressure drop vector with respect to the disc. The disc was predicted to reach its highest velocity at the moment of impact, based on the Runge-Kutta solution. Modelling suggests that a high LV dP/dt during valve closure or distorted LV geometry, causing the angle between the fully open disc and the pressure drop vector to shift, will cause the valve to have a high velocity at the moment of impact and may produce high impact loads.

  1. Color flow imaging of the vena contracta in mitral regurgitation: technical considerations.

    PubMed

    Roberts, Brad J; Grayburn, Paul A

    2003-09-01

    Qualitative grading of mitral regurgitation severity has significant pitfalls secondary to hemodynamic variables, sonographic technique, blood pool entrainment, and the Coanda effect. Volumetric and proximal isovelocity surface area methods can be used to quantitate regurgitant orifice area, regurgitant volume, and regurgitant fraction, but have several limitations and can pose technical challenges. The vena contracta width method provides a rapid and accurate quantitative assessment of mitral regurgitation severity, but is clinically underused. This article is intended to generate an understanding of the flow mechanics of the vena contracta and the sonographic technique required to provide consistent and accurate measurements of vena contracta width in patients with mitral regurgitation.

  2. Effect of grinding with diamond-disc and -bur on the mechanical behavior of a Y-TZP ceramic.

    PubMed

    Pereira, G K R; Amaral, M; Simoneti, R; Rocha, G C; Cesar, P F; Valandro, L F

    2014-09-01

    This study compared the effects of grinding on the surface micromorphology, phase transformation (t→m), biaxial flexural strength and structural reliability (Weibull analysis) of a Y-TZP (Lava) ceramic using diamond-discs and -burs. 170 discs (15×1.2mm) were produced and divided into 5 groups: without treatment (Ctrl, as-sintered), and ground with 4 different systems: extra-fine (25µm, Xfine) and coarse diamond-bur (181µm, Coarse), 600-grit (25µm, D600) and 120-grit diamond-disc (160µm, D120). Grinding with burs was performed using a contra-angle handpiece (T2-Revo R170, Sirona), while for discs (Allied) a Polishing Machine (Ecomet, Buehler) was employed, both under water-cooling. Micromorphological analysis showed distinct patterns generated by grinding with discs and burs, independent of grit size. There was no statistical difference for characteristic strength values (MPa) between smaller grit sizes (D600 - 1050.08 and Xfine - 1171.33), although they presented higher values compared to Ctrl (917.58). For bigger grit sizes, a significant difference was observed (Coarse - 1136.32>D120 - 727.47). Weibull Modules were statistically similar between the tested groups. Within the limits of this study, from a micromorphological point-of-view, the treatments performed did not generate similar effects, so from a methodological point-of-view, diamond-discs should not be employed to simulate clinical abrasion performed with diamond-burs on Y-TZP ceramics.

  3. Cyanoacrylate medical glue application in intervertebral disc annulus defect repair: Mechanical and biocompatible evaluation.

    PubMed

    Kang, Ran; Li, Haisheng; Lysdahl, Helle; Quang Svend Le, Dang; Chen, Menglin; Xie, Lin; Bünger, Cody

    2017-01-01

    In an attempt to find an ideal closure method during annulus defect repair, we evaluate the use of medical glue by mechanical and biocompatible test. Cyanoacrylate medical glue was applied together with a multilayer microfiber/nanofiber polycaprolactone scaffold and suture in annulus repair. Continuous axial loading and fatigue mechanical test was performed. Furthermore, the in vitro response of mesenchymal stem cell (MSC) to the glue was evaluated by cell viability assay. The in vivo response of annulus tissue to the glue and scaffold was also studied in porcine lumbar spine; histological sections were evaluated after 3 months. Cyanoacrylate glue significantly improved the closure effect in the experimental group with failure load 2825.7 ± 941.6 N, compared to 774.1 ± 281.3 N in the control group without glue application (p < 0.01). The experimental group also withstood the fatigue test. No toxic effect was observed by in vitro cell culture and in vivo implantation. On the basis of this initial evaluation, the use of cyanoacrylate medical glue improves closure effect with no toxicity in annulus defect repair. This method of annulus repair merits further effectiveness study in vivo. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 14-20, 2017.

  4. Mitral valve plasty for mitral regurgitation after blunt chest trauma.

    PubMed

    Kumagai, H; Hamanaka, Y; Hirai, S; Mitsui, N; Kobayashi, T

    2001-06-01

    A 21 year-old woman was admitted to our hospital because of chest and back pain after blunt chest trauma. On admission, consciousness was clear and a physical examination showed labored breathing. Her vital signs were stable, but her breathing gradually worsened, and artificial respiration was started. The chest roentgenogram and a subsequent chest computed tomographic scans revealed contusions, hemothorax of the left lung and multiple rib fractures. A transthoracic echocardiography (TTE) revealed normal left ventricular wall motion and mild mitral regurgitation (MR). TTE was carried out repeatedly, and revealed gradually progressive MR and prolapse of the posterior medial leaflet, although there was no congestive heart failure. After her general condition had recovered, surgery was performed. Intraoperative transesophageal echocardiography (TEE) revealed torn chordae at the posterior medial leaflet. The leaflet where the chorda was torn was cut and plicated, and posterior mitral annuloplasty was performed using a prosthetic ring. One month later following discharge, the MR had disappeared on TTE.

  5. Mitral Valve Replacement After Failed Mitral Ring Insertion With or Without Leaflet/Chordal Repair for Pure Mitral Regurgitation.

    PubMed

    Roberts, William C; Moore, Meagan; Ko, Jong Mi; Hamman, Baron L

    2016-06-01

    Mitral repair operations for correction of pure mitral regurgitation (MR) are generally quite successful. Occasionally, however, the reparative procedure incompletely corrects the MR or the MR recurs. From March 1993 to January 2016, twenty nine patients had mitral valve replacement after the initial mitral repair operation, and observations in them were analyzed. All 29 patients at the repair operation had an annular ring inserted and later (<1 year in 6 and >1 year in 21) mitral valve replacement. The cause of the MR before the repair operation appears to have been prolapse in 16 patients (55%), secondary (functional) in 12 (41%) (ischemic in 5), and infective endocarditis which healed in 1 (3%). At the replacement operation the excised anterior mitral leaflet was thickened in all 29 patients. Some degree of stenosis appeared to have been present in 16 of the 29 patients before the replacement operation, although only 10 had an echocardiographic or hemodynamic recording of a transvalvular gradient; at least 11 patients had restricted motion of the posterior mitral leaflet; 10, ring dehiscence; 2, severe hemolysis; and 2, left ventricular outflow obstruction. In conclusion, there are multiple reasons for valve replacement after earlier mitral repair. Uniformly, at the time of the replacement, the mitral leaflets were thickened by fibrous tissue. Measurement of the area enclosed by the 360° rings and study of the excised leaflet suggest that the ring itself may have contributed to the leaflet scarring and development of some transmitral stenosis.

  6. [Valvular surgery for an exercise-induced functional mitral regurgitation in heart failure and preserved ejection fraction: a case study].

    PubMed

    Attari, M; Legrand, M; Philippe, C; Rosak, P

    2013-08-01

    We here report the case of a 67-year-old woman with moderate mitral regurgitation without significant structural abnormalities that get worse during severe recurrent heart failures and preserved ejection fraction with concomitant paroxysmal atrial fibrillation. Atrial fibrillation became permanent and despite a well-controlled cardiac frequency, new heart failure episodes occurred. Exercise doppler echocardiography showed that the mechanism of this mitral regurgitation was a two leaflet mitral tenting. We discuss here the different mechanisms that could induce these kinds of mitral regurgitation with excessive tenting. We emphasize the interest of early detection by exercise doppler echocardiography even when a triggering factor like atrial fibrillation seems to be involved. We also discuss the interest of mitral valve replacement for these patients.

  7. Successful balloon mitral valvotomy in a rare coexistence of Ebstein's anomaly and rheumatic mitral stenosis.

    PubMed

    Sidhu, Navdeep Singh; Kondethimmanahally Rangaiah, Sunil Kumar; Ramesh, Dwarikaprasad; Manjunath, Cholenahally Nanjappa

    2016-05-05

    Co-existence of Ebstein's anomaly of the tricuspid valve with rheumatic mitral stenosis is a very rare occurrence. We report the case of a young man who presented with progressive dyspnoea and was found to have rheumatic mitral stenosis with pulmonary hypertension and Ebstein's anomaly of the tricuspid valve. The patient underwent successful balloon mitral valvotomy resulting in marked improvement of symptoms.

  8. A Remnant Mitral Subvalvular Apparatus Mimicking Aortic Valve Vegetation after Mitral Valve Replacement

    PubMed Central

    Kim, Hyun-Jin; Kim, Kyung-Hee; Choi, Jae-Sung; Kim, Jun-Sung; Kim, Myung-A

    2012-01-01

    Preservation of the subvalvular apparatus has the merits of postoperative outcomes during mitral valve replacement for mitral regurgitation. We performed mitral valve replacement with anterior and posterior leaflet chordal preservation in a 65-year-old woman. On the 2nd postoperative day, routine postoperative trans-thoracic echocardiography showed an unknown aortic subvalvular mobile mass. We report a case of a remnant mitral subvalvular apparatus detected by echocardiography after chordal preserving mitral valve replacement which was confused with postoperative aortic valve vegetation. PMID:22509443

  9. Percutaneous Rescue for Critical Mitral Stenosis Late After Mitral Valve Repair.

    PubMed

    Salenger, Rawn; Diao, Xavier; Dawood, Murtaza Y; Herr, Daniel L; Sample, George A; Pichard, Augusto; Gammie, James S

    2016-11-01

    We report a case of catastrophic hemodynamic compromise secondary to pannus ingrowth and severe mitral stenosis occurring years after repair of a nonrheumatic mitral valve. The initial repair included closure of a posterior leaflet cleft and implantation of an annuloplasty ring. We describe a hybrid treatment strategy for this severely compromised patient, which included initial placement of a right ventricular assist device followed by percutaneous balloon mitral valvuloplasty and, eventually, a definitive mitral valve reoperation. This case report reinforces the importance of routine clinical and echocardiographic follow-up for patients after mitral valve repair, and it includes the description of a novel therapeutic approach.

  10. A complex transcatheter mitral valve replacement and repair for the treatmemt of refractory severe mitral regurgitation.

    PubMed

    Condado, Jose F; Babaliaros, Vasilis C; Thourani, Vinod H; Jensen, Hanna K; Kim, Dennis W; Kaebnick, Brian W; Block, Peter C; Lerakis, Stamatios

    2017-01-23

    Hybrid transcatheter Mitral Valve-in-Ring and Mitral Valve-in-Valve procedures can be an alternative to traditional surgical valve replacement in patients with high surgical risk. We present a case of a 65-year-old male with recurrent severe mitral regurgitation (MR) that failed two traditional surgical attempts due to severe chest fibrosis. We performed a mitral valve-in ring replacement with a Sapien valve followed by a mitral valve-in-valve replacement with a Melody valve. Patient had a residual paravalvular leak that was closed with a vascular plug. Our case proves that is feasible to treat selected patients with MR using a hybrid transcatheter approach.

  11. Imaginal disc regeneration takes flight.

    PubMed

    Hariharan, Iswar K; Serras, Florenci

    2017-04-01

    Drosophila imaginal discs, the larval precursors of adult structures such as the wing and leg, are capable of regenerating after damage. During the course of regeneration, discs can sometimes generate structures that are appropriate for a different type of disc, a phenomenon termed transdetermination. Until recently, these phenomena were studied by physically fragmenting discs and then transplanting them into the abdomens of adult female flies. This field has experienced a renaissance following the development of genetic ablation systems that can damage precisely defined regions of the disc without the need for surgery. Together with more traditional approaches, these newer methods have generated many novel insights into wound healing, the mechanisms that drive regenerative growth, plasticity during regeneration and systemic effects of tissue damage and regeneration.

  12. Nuclear factor-kappa B decoy suppresses nerve injury and improves mechanical allodynia and thermal hyperalgesia in a rat lumbar disc herniation model

    PubMed Central

    Suzuki, Munetaka; Inoue, Gen; Gemba, Takefumi; Watanabe, Tomoko; Ito, Toshinori; Koshi, Takana; Yamauchi, Kazuyo; Yamashita, Masaomi; Orita, Sumihisa; Eguchi, Yawara; Ochiai, Nobuyasu; Kishida, Shunji; Takaso, Masashi; Aoki, Yasuchika; Takahashi, Kazuhisa

    2009-01-01

    Nuclear factor-kappa B (NF-κB) is a gene transcriptional regulator of inflammatory cytokines. We investigated the transduction efficiency of NF-κB decoy to dorsal root ganglion (DRG), as well as the decrease in nerve injury, mechanical allodynia, and thermal hyperalgesia in a rat lumbar disc herniation model. Forty rats were used in this study. NF-κB decoy–fluorescein isothiocyanate (FITC) was injected intrathecally at the L5 level in five rats, and its transduction efficiency into DRG measured. In another 30 rats, mechanical pressure was placed on the DRG at the L5 level and nucleus pulposus harvested from the rat coccygeal disc was transplanted on the DRG. Rats were classified into three groups of ten animals each: a herniation + decoy group, a herniation + oligo group, and a herniation only group. For behavioral testing, mechanical allodynia and thermal hyperalgesia were evaluated. In 15 of the herniation rats, their left L5 DRGs were resected, and the expression of activating transcription factor 3 (ATF-3) and calcitonin gene-related peptide (CGRP) was evaluated immunohistochemically compared to five controls. The total transduction efficiency of NF-κB decoy–FITC in DRG neurons was 10.8% in vivo. The expression of CGRP and ATF-3 was significantly lower in the herniation + decoy group than in the other herniation groups. Mechanical allodynia and thermal hyperalgesia were significantly suppressed in the herniation + decoy group. NF-κB decoy was transduced into DRGs in vivo. NF-κB decoy may be useful as a target for clarifying the mechanism of sciatica caused by lumbar disc herniation. PMID:19308465

  13. Nuclear factor-kappa B decoy suppresses nerve injury and improves mechanical allodynia and thermal hyperalgesia in a rat lumbar disc herniation model.

    PubMed

    Suzuki, Munetaka; Inoue, Gen; Gemba, Takefumi; Watanabe, Tomoko; Ito, Toshinori; Koshi, Takana; Yamauchi, Kazuyo; Yamashita, Masaomi; Orita, Sumihisa; Eguchi, Yawara; Ochiai, Nobuyasu; Kishida, Shunji; Takaso, Masashi; Aoki, Yasuchika; Takahashi, Kazuhisa; Ohtori, Seiji

    2009-07-01

    Nuclear factor-kappa B (NF-kappaB) is a gene transcriptional regulator of inflammatory cytokines. We investigated the transduction efficiency of NF-kappaB decoy to dorsal root ganglion (DRG), as well as the decrease in nerve injury, mechanical allodynia, and thermal hyperalgesia in a rat lumbar disc herniation model. Forty rats were used in this study. NF-kappaB decoy-fluorescein isothiocyanate (FITC) was injected intrathecally at the L5 level in five rats, and its transduction efficiency into DRG measured. In another 30 rats, mechanical pressure was placed on the DRG at the L5 level and nucleus pulposus harvested from the rat coccygeal disc was transplanted on the DRG. Rats were classified into three groups of ten animals each: a herniation + decoy group, a herniation + oligo group, and a herniation only group. For behavioral testing, mechanical allodynia and thermal hyperalgesia were evaluated. In 15 of the herniation rats, their left L5 DRGs were resected, and the expression of activating transcription factor 3 (ATF-3) and calcitonin gene-related peptide (CGRP) was evaluated immunohistochemically compared to five controls. The total transduction efficiency of NF-kappaB decoy-FITC in DRG neurons was 10.8% in vivo. The expression of CGRP and ATF-3 was significantly lower in the herniation + decoy group than in the other herniation groups. Mechanical allodynia and thermal hyperalgesia were significantly suppressed in the herniation + decoy group. NF-kappaB decoy was transduced into DRGs in vivo. NF-kappaB decoy may be useful as a target for clarifying the mechanism of sciatica caused by lumbar disc herniation.

  14. Ross-Kabbani Operation in an Infant with Mitral Valve Dysplasia

    PubMed Central

    Napoleone, Carlo Pace; Oppido, Guido; Angeli, Emanuela; Giardini, Alessandro; Gargiulo, Gaetano

    2009-01-01

    Background. Mitral valve replacement can be very difficult to obtain in infants because the valve annulus diameter can be smaller than the available prosthesis. Case Report. We describe the case of a 2-month-old female weighing 3.5 kg affected by mitral valve dysplasia leading to severe valve stenosis. Despite full medication, the clinical conditions were critical and surgery was undertaken. The mitral valve was unsuitable for repair and the orifice of mitral anulus was 12 mm, too small for a mechanical prosthesis. Therefore, a Ross-Kabbani operation was undertaken, replacing the mitral valve with the pulmonary autograft and reconstructing the right ventricular outflow tract with an etherograft. Results. The postoperative course was uneventful and the clinical conditions are good at 4-month follow-up. Conclusion. The Ross-Kabbani operation can be an interesting alternative to mitral valve replacement in infants when valve repair is not achievable and there is little space for an intra-annular mechanical prosthesis implant. PMID:20049318

  15. Minimally Invasive Mitral Valve Surgery I

    PubMed Central

    Ailawadi, Gorav; Agnihotri, Arvind K.; Mehall, John R.; Wolfe, J. Alan; Hummel, Brian W.; Fayers, Trevor M.; Farivar, R. Saeid; Grossi, Eugene A.; Guy, T. Sloane; Hargrove, W. Clark; Khan, Junaid H.; Lehr, Eric J.; Malaisrie, S. Chris; Murphy, Douglas A.; Rodriguez, Evelio; Ryan, William H.; Salemi, Arash; Segurola, Romualdo J.; Shemin, Richard J.; Smith, J. Michael; Smith, Robert L.; Weldner, Paul W.; Goldman, Scott M.; Lewis, Clifton T. P.; Barnhart, Glenn R.

    2016-01-01

    Abstract Widespread adoption of minimally invasive mitral valve repair and replacement may be fostered by practice consensus and standardization. This expert opinion, first of a 3-part series, outlines current best practices in patient evaluation and selection for minimally invasive mitral valve procedures, and discusses preoperative planning for cannulation and myocardial protection. PMID:27654407

  16. In vitro assessment of a combined radiofrequency ablation and cryo-anchoring catheter for treatment of mitral valve prolapse.

    PubMed

    Boronyak, Steven M; Merryman, W David

    2014-03-21

    Percutaneous approaches to mitral valve repair are an attractive alternative to surgical repair or replacement. Radiofrequency ablation has the potential to approximate surgical leaflet resection by using resistive heating to reduce leaflet size, and cryogenic temperatures on a percutaneous catheter can potentially be used to reversibly adhere to moving mitral valve leaflets for reliable application of radiofrequency energy. We tested a combined cryo-anchoring and radiofrequency ablation catheter using excised porcine mitral valves placed in a left heart flow loop capable of reproducing physiologic pressure and flow waveforms. Transmitral flow and pressure were monitored during the cryo-anchoring procedure and compared to baseline flow conditions, and the extent of radiofrequency energy delivery to the mitral valve was assessed post-treatment. Long term durability of radiofrequency ablation treatment was assessed using statically treated leaflets placed in a stretch bioreactor for four weeks. Transmitral flow and pressure waveforms were largely unaltered during cryo-anchoring. Parameter fitting to mechanical data from leaflets treated with radiofrequency ablation and cryo-anchoring revealed significant mechanical differences from untreated leaflets, demonstrating successful ablation of mitral valves in a hemodynamic environment. Picrosirius red staining showed clear differences in morphology and collagen birefringence between treated and untreated leaflets. The durability study indicated that statically treated leaflets did not significantly change size or mechanics over four weeks. A cryo-anchoring and radiofrequency ablation catheter can adhere to and ablate mitral valve leaflets in a physiologic hemodynamic environment, providing a possible percutaneous alternative to surgical leaflet resection of mitral valve tissue.

  17. Normal human mitral valve proteome: A preliminary investigation by gel-based and gel-free proteomic approaches.

    PubMed

    Brioschi, Maura; Baetta, Roberta; Ghilardi, Stefania; Gianazza, Erica; Guarino, Anna; Parolari, Alessandro; Polvani, Gianluca; Tremoli, Elena; Banfi, Cristina

    2016-10-01

    The mitral valve is a highly complex structure which regulates blood flow from the left atrium to the left ventricle (LV) avoiding a significant forward gradient during diastole or regurgitation during systole. The integrity of the mitral valve is also essential for the maintenance of normal LV size, geometry, and function. Significant advances in the comprehension of the biological, functional, and mechanical behavior of the mitral valve have recently been made. However, current knowledge of protein components in the normal human mitral valve is still limited and complicated by the low cellularity of this tissue and the presence of high abundant proteins from the extracellular matrix. We employed here an integrated proteomic approach to analyse the protein composition of the normal human mitral valve and reported confident identification of 422 proteins, some of which have not been previously described in this tissue. In particular, we described the ability of pre-MS separation technique based on liquid-phase IEF and SDS-PAGE to identify the largest number of proteins. We also demonstrated that some of these proteins, e.g. αB-Crystallin, septin-11, four-and-a-half LIM domains protein 1, and dermatopontin, are synthesised by interstitial cells isolated from human mitral valves. These initial results provide a valuable basis for future studies aimed at analysing in depth the mitral valve protein composition and at investigating potential pathogenetic molecular mechanisms. Data are available via ProteomeXchange with identifier PXD004397.

  18. Archival-grade optical disc design and international standards

    NASA Astrophysics Data System (ADS)

    Fujii, Toru; Kojyo, Shinichi; Endo, Akihisa; Kodaira, Takuo; Mori, Fumi; Shimizu, Atsuo

    2015-09-01

    Optical discs currently on the market exhibit large variations in life span among discs, making them unsuitable for certain business applications. To assess and potentially mitigate this problem, we performed accelerated degradation testing under standard ISO conditions, determined the probable disc failure mechanisms, and identified the essential criteria necessary for a stable disc composition. With these criteria as necessary conditions, we analyzed the physical and chemical changes that occur in the disc components, on the basis of which we determined technological measures to reduce these degradation processes. By applying these measures to disc fabrication, we were able to develop highly stable optical discs.

  19. Circumplanetary discs around young giant planets: a comparison between core-accretion and disc instability

    NASA Astrophysics Data System (ADS)

    Szulágyi, J.; Mayer, L.; Quinn, T.

    2017-01-01

    Circumplanetary discs can be found around forming giant planets, regardless of whether core accretion or gravitational instability built the planet. We carried out state-of-the-art hydrodynamical simulations of the circumplanetary discs for both formation scenarios, using as similar initial conditions as possible to unveil possible intrinsic differences in the circumplanetary disc mass and temperature between the two formation mechanisms. We found that the circumplanetary discs' mass linearly scales with the circumstellar disc mass. Therefore, in an equally massive protoplanetary disc, the circumplanetary discs formed in the disc instability model can be only a factor of 8 more massive than their core-accretion counterparts. On the other hand, the bulk circumplanetary disc temperature differs by more than an order of magnitude between the two cases. The subdiscs around planets formed by gravitational instability have a characteristic temperature below 100 K, while the core-accretion circumplanetary discs are hot, with temperatures even greater than 1000 K when embedded in massive, optically thick protoplanetary discs. We explain how this difference can be understood as the natural result of the different formation mechanisms. We argue that the different temperatures should persist up to the point when a full-fledged gas giant forms via disc instability; hence, our result provides a convenient criterion for observations to distinguish between the two main formation scenarios by measuring the bulk temperature in the planet vicinity.

  20. Transapical Mitral Valve Replacement for Mixed Native Mitral Stenosis and Regurgitation.

    PubMed

    Bedzra, Edo; Don, Creighton W; Reisman, Mark; Aldea, Gabriel S

    2016-08-01

    A 71-year-old man presented with New York Heart Association (NYHA) class IV heart failure. He had undergone transapical mitral valve replacement for mixed mitral stenosis and mitral regurgitation. At the 1 month follow-up, the patient reported symptom resolution. An echocardiogram revealed a low gradient and no regurgitation. Our case shows that with careful multidisciplinary evaluation, preoperative planning, and patient selection, percutaneous mitral intervention can become an alternative therapy for high-risk patients who cannot undergo conventional surgical therapy.

  1. Challenging mitral valve repair for double-orifice mitral valve with noncompaction of left ventricular myocardium.

    PubMed

    Yamasaki, Manabu; Misumi, Hiroyasu; Abe, Kohei; Kawazoe, Kohei

    2017-02-25

    Double-orifice mitral valve (DOMV) is a relatively rare cardiac anomaly. Although usually associated with various cardiac anomalies, co-presence of DOMV and noncompaction of left ventricular myocardium (NCLVM) is extremely rare. Here, we present a 24-year-old male who underwent mitral valve repair using artificial chordae and annuloplasty at the posterior commissure for severe mitral regurgitation (MR), resulting from flail anterior leaflet of the larger postero-medial orifice and dilatation of left ventricle with NCLVM. One year later, he underwent second mitral valve repair for recurrence of MR. Further endoscopic evaluation of the left ventricle, and reinforcement via artificial ring, enabled us to achieve repair.

  2. The relief of mitral stenosis. An historic step in cardiac surgery.

    PubMed Central

    Khan, M N

    1996-01-01

    Significant progress has been achieved in cardiac surgery in the last 50 years. Mitral valve surgery (especially for the relief of mitral stenosis) has paralleled the innovations and trends of cardiac surgery and often has served as the benchmark of the latest procedures and techniques. A chronological survey of mitral valve surgery is presented, with emphasis on parallels to cardiac surgery in general and with highlights of key figures and events that have conclusively altered the surgeon's approach to and success with cardiac dysfunction. A few surgeons promulgated the idea of cardiac surgery in the late 19th century, but mitral valve surgeries were not performed in earnest until Souttar's and Cutler's initial attempts in the 1920s and were not successful on large groups of patients until Bailey and Harken made independent breakthroughs in the 1940s, finally laying to rest the idea of the "inviolable heart." Cardiopulmonary bypass provided cardiac surgeons with the time to implant mechanical and bioprosthetic valves for palliative benefit to patients. The "perfect" valve has yet to be found, but the Starr-Edwards mechanical valve since its inception in 1961 has been one of the most successful and widely used prosthetic valves. Gradual improvement in surgical technique and growing knowledge of valve function enabled the re-emergence of mitral valve repair in the 1980s as the preferred surgical method of treating mitral stenosis. In the last 10 years, mitral valve balloon dilation has provided a nonsurgical technique for relief of stenosis and represents the broader trend towards interventional techniques. Images PMID:8969024

  3. Stabilized Collagen and Elastin-Based Scaffolds for Mitral Valve Tissue Engineering.

    PubMed

    Deborde, Christopher; Simionescu, Dan Teodor; Wright, Cristopher; Liao, Jun; Sierad, Leslie Neil; Simionescu, Agneta

    2016-11-01

    There is a significant clinical need for new approaches to treatment of mitral valve disease. The aim of this study was to develop a tissue-engineered mitral valve scaffold possessing appropriate composition and structure to ensure ideal characteristics of mitral valves, such as large orifice, rapid opening and closure, maintenance of mitral annulus-papillary muscle continuity, in vivo biocompatibility and extended durability. An extracellular matrix-based scaffold was generated, based on the native porcine mitral valve as starting material and a technique for porcine cell removal without causing damage to the matrix components. To stabilize these structures and slow down their degradation, acellular scaffolds were treated with penta-galloyl glucose (PGG), a well-characterized polyphenol with high affinity for collagen and elastin. Biaxial mechanical testing presented similar characteristics for the PGG-treated scaffolds compared to fresh tissues. The extracellular matrix components, crucial for maintaining the valve shape and function, were well preserved in leaflets, and in chordae, as shown by their resistance to collagenase and elastin. When extracted with strong detergents, the PGG-treated scaffolds released a reduced amount of soluble matrix peptides, compared to untreated scaffolds; this correlated with diminished activation of fibroblasts seeded on scaffolds treated with PGG. Cell-seeded scaffolds conditioned for 5 weeks in a valve bioreactor showed good cell viability. Finally, rat subdermal implantation studies showed that PGG-treated mitral valve scaffolds were biocompatible, nonimmunogenic, noninflammatory, and noncalcifying. In conclusion, a biocompatible mitral valve scaffold was developed, which preserved the biochemical composition and structural integrity of the valve, essential for its highly dynamic mechanical demands, and its biologic durability.

  4. Biomechanics of Disc Degeneration

    PubMed Central

    Palepu, V.; Kodigudla, M.; Goel, V. K.

    2012-01-01

    Disc degeneration and associated disorders are among the most debated topics in the orthopedic literature over the past few decades. These may be attributed to interrelated mechanical, biochemical, and environmental factors. The treatment options vary from conservative approaches to surgery, depending on the severity of degeneration and response to conservative therapies. Spinal fusion is considered to be the “gold standard” in surgical methods till date. However, the association of adjacent level degeneration has led to the evolution of motion preservation technologies like spinal arthroplasty and posterior dynamic stabilization systems. These new technologies are aimed to address pain and preserve motion while maintaining a proper load sharing among various spinal elements. This paper provides an elaborative biomechanical review of the technologies aimed to address the disc degeneration and reiterates the point that biomechanical efficacy followed by long-term clinical success will allow these nonfusion technologies as alternatives to fusion, at least in certain patient population. PMID:22745914

  5. Redundant disc

    NASA Technical Reports Server (NTRS)

    Barack, W. N.; Domas, P. A.; Beekman, S. W. (Inventor)

    1978-01-01

    A rotatable disc is described that consists of parallel plates tightly joined together for rotation about a hub. Each plate is provided with several angularly projecting spaced lands. The lands of each plate are interposed in alternating relationship between the lands of the next adjacent plate. In this manner, circumferential displacement of adjacent sectors in any one plate is prevented in the event that a crack develops. Each plate is redundantly sized so that, in event of structural failure of one plate, the remaining plates support a proportionate share of the load of the failed plate. The plates are prevented from separating laterally through the inclusion of generally radially extending splines which are inserted to interlock cooperating, circumferentially adjacent lands.

  6. Mitral Valve Clip for Treatment of Mitral Regurgitation: An Evidence-Based Analysis

    PubMed Central

    Ansari, Mohammed T.; Ahmadzai, Nadera; Coyle, Kathryn; Coyle, Doug; Moher, David

    2015-01-01

    Background Many of the 500,000 North American patients with chronic mitral regurgitation may be poor candidates for mitral valve surgery. Objective The objective of this study was to investigate the comparative effectiveness, harms, and cost-effectiveness of percutaneous mitral valve repair using mitral valve clips in candidates at prohibitive risk for surgery. Data Sources We searched articles in MEDLINE, Embase, and the Cochrane Library published from 1994 to February 2014 for evidence of effectiveness and harms; for economic literature we also searched NHS EED and Tufts CEA registry. Grey literature was also searched. Review Methods Primary studies were sought from existing systematic reviews that had employed reliable search and screening methods. Newer studies were sought by searching the period subsequent to the last search date of the review. Two reviewers screened records and assessed study validity. We used the Cochrane risk of bias tool for randomized, generic assessment for non-randomized studies, and the Phillips checklist for economic studies. Results Ten studies including 1 randomized trial were included. The majority of the direct comparative evidence compared the mitral valve clip repair with surgery in patients not particularly at prohibitive surgical risk. Irrespective of degenerative or functional chronic mitral regurgitation etiology, evidence of effectiveness and harms is inconclusive and of very low quality. Very-low-quality evidence indicates that percutaneous mitral valve clip repair may provide a survival advantage, at least during the first 1 to 2 years, particularly in medically managed chronic functional mitral regurgitation. Because of limitations in the design of studies, the cost-effectiveness of mitral valve clips in patients at prohibitive risk for surgery also could not be established. Limitations Because of serious concerns of risk of bias, indirectness, and imprecision, evidence is of very low quality. Conclusions No meaningful

  7. Proto-planetary disc evolution and dispersal

    NASA Astrophysics Data System (ADS)

    Rosotti, Giovanni Pietro

    2015-05-01

    Planets form from gas and dust discs in orbit around young stars. The timescale for planet formation is constrained by the lifetime of these discs. The properties of the formed planetary systems depend thus on the evolution and final dispersal of the discs, which is the main topic of this thesis. Observations reveal the existence of a class of discs called "transitional", which lack dust in their inner regions. They are thought to be the last stage before the complete disc dispersal, and hence they may provide the key to understanding the mechanisms behind disc evolution. X-ray photoevaporation and planet formation have been studied as possible physical mechanisms responsible for the final dispersal of discs. However up to now, these two phenomena have been studied separately, neglecting any possible feedback or interaction. In this thesis we have investigated what is the interplay between these two processes. We show that the presence of a giant planet in a photo-evaporating disc can significantly shorten its lifetime, by cutting the inner regions from the mass reservoir in the exterior of the disc. This mechanism produces transition discs that for a given mass accretion rate have larger holes than in models considering only X-ray photo-evaporation, constituting a possible route to the formation of accreting transition discs with large holes. These discs are found in observations and still constitute a puzzle for the theory. Inclusion of the phenomenon called "thermal sweeping", a violent instability that can destroy a whole disc in as little as 10 4 years, shows that the outer disc left can be very short-lived (depending on the X-ray luminosity of the star), possibly explaining why very few non accreting transition discs are observed. However the mechanism does not seem to be efficient enough to reconcile with observations. In this thesis we also show that X-ray photo-evaporation naturally explains the observed correlation between stellar masses and accretion

  8. Regurgitation Hemodynamics Alone Cause Mitral Valve Remodeling Characteristic of Clinical Disease States In Vitro.

    PubMed

    Connell, Patrick S; Azimuddin, Anam F; Kim, Seulgi E; Ramirez, Fernando; Jackson, Matthew S; Little, Stephen H; Grande-Allen, K Jane

    2016-04-01

    Mitral valve regurgitation is a challenging clinical condition that is frequent, highly varied, and poorly understood. While the causes of mitral regurgitation are multifactorial, how the hemodynamics of regurgitation impact valve tissue remodeling is an understudied phenomenon. We employed a pseudo-physiological flow loop capable of long-term organ culture to investigate the early progression of remodeling in living mitral valves placed in conditions resembling mitral valve prolapse (MVP) and functional mitral regurgitation (FMR). Valve geometry was altered to mimic the hemodynamics of controls (no changes from native geometry), MVP (5 mm displacement of papillary muscles towards the annulus), and FMR (5 mm apical, 5 mm lateral papillary muscle displacement, 65% larger annular area). Flow measurements ensured moderate regurgitant fraction for regurgitation groups. After 1-week culture, valve tissues underwent mechanical and compositional analysis. MVP conditioned tissues were less stiff, weaker, and had elevated collagen III and glycosaminoglycans. FMR conditioned tissues were stiffer, more brittle, less extensible, and had more collagen synthesis, remodeling, and crosslinking related enzymes and proteoglycans, including decorin, matrix metalloproteinase-1, and lysyl oxidase. These models replicate clinical findings of MVP (myxomatous remodeling) and FMR (fibrotic remodeling), indicating that valve cells remodel extracellular matrix in response to altered mechanical homeostasis resulting from disease hemodynamics.

  9. Double-orifice mitral valve treated by percutaneous balloon valvuloplasty.

    PubMed

    Varghese, Thomas George; Revankar, Vinod Raghunath; Papanna, Monica; Srinivasan, Harshini

    2016-07-01

    Double-orifice mitral valve is an rare anomaly characterized by a mitral valve with a single fibrous annulus and 2 orifices that open into the left ventricle. It is often associated with other congenital anomalies, most commonly atrioventricular canal defects, and rarely associated with a stenotic or regurgitant mitral valve. A patient who was diagnosed with congenital double-orifice mitral valve with severe mitral stenosis was treated successfully by percutaneous balloon mitral valvotomy rather than the conventional open surgical approach, demonstrating the utility of percutaneous correction of this anomaly.

  10. Evaluation of a Shape Memory Alloy Reinforced Annuloplasty Band for Minimally Invasive Mitral Valve Repair

    PubMed Central

    Purser, Molly F.; Richards, Andrew L.; Cook, Richard C.; Osborne, Jason A.; Cormier, Denis R.; Buckner, Gregory D.

    2013-01-01

    Purpose An in vitro study using explanted porcine hearts was conducted to evaluate a novel annuloplasty band, reinforced with a two-phase, shape memory alloy, designed specifically for minimally invasive mitral valve repair. Description In its rigid (austenitic) phase, this band provides the same mechanical properties as the commercial semi-rigid bands. In its compliant (martensitic) phase, this band is flexible enough to be introduced through an 8-mm trocar and is easily manipulated within the heart. Evaluation In its rigid phase, the prototype band displayed similar mechanical properties to commercially available semi-rigid rings. Dynamic flow testing demonstrated no statistical differences in the reduction of mitral valve regurgitation. In its flexible phase, the band was easily deployed through an 8-mm trocar, robotically manipulated and sutured into place. Conclusions Experimental results suggest that the shape memory alloy reinforced band could be a viable alternative to flexible and semi-rigid bands in minimally invasive mitral valve repair. PMID:19766827

  11. Nectin-1 spots as a novel adhesion apparatus that tethers mitral cell lateral dendrites in a dendritic meshwork structure of the developing mouse olfactory bulb.

    PubMed

    Inoue, Takahito; Fujiwara, Takeshi; Rikitake, Yoshiyuki; Maruo, Tomohiko; Mandai, Kenji; Kimura, Kazushi; Kayahara, Tetsuro; Wang, Shujie; Itoh, Yu; Sai, Kousyoku; Mori, Masahiro; Mori, Kensaku; Mizoguchi, Akira; Takai, Yoshimi

    2015-08-15

    Mitral cells project lateral dendrites that contact the lateral and primary dendrites of other mitral cells and granule cell dendrites in the external plexiform layer (EPL) of the olfactory bulb. These dendritic structures are critical for odor information processing, but it remains unknown how they are formed. In immunofluorescence microscopy, the immunofluorescence signal for the cell adhesion molecule nectin-1 was concentrated on mitral cell lateral dendrites in the EPL of the developing mouse olfactory bulb. In electron microscopy, the immunogold particles for nectin-1 were symmetrically localized on the plasma membranes at the contacts between mitral cell lateral dendrites, which showed bilateral darkening without dense cytoskeletal undercoats characteristic of puncta adherentia junctions. We named the contacts where the immunogold particles for nectin-1 were symmetrically accumulated "nectin-1 spots." The nectin-1 spots were 0.21 μm in length on average and the distance between the plasma membranes was 20.8 nm on average. In 3D reconstruction of serial sections, clusters of the nectin-1 spots formed a disc-like structure. In the mitral cell lateral dendrites of nectin-1-knockout mice, the immunogold particles for nectin-1 were undetectable and the plasma membrane darkening was electron-microscopically normalized, but the plasma membranes were partly separated from each other. The nectin-1 spots were further identified between mitral cell lateral and primary dendrites and between mitral cell lateral dendrites and granule cell dendritic spine necks. These results indicate that the nectin-1 spots constitute a novel adhesion apparatus that tethers mitral cell dendrites in a dendritic meshwork structure of the developing mouse olfactory bulb.

  12. Development and Validation of a Bioreactor System for Dynamic Loading and Mechanical Characterization of Whole Human Intervertebral Discs in Organ Culture

    PubMed Central

    Walter, BA; Illien-Junger, S; Nasser, P; Hecht, AC; Iatridis, JC

    2014-01-01

    Intervertebral disc (IVD) degeneration is a common cause of back pain, and attempts to develop therapies are frustrated by lack of model systems that mimic the human condition. Human IVD organ culture models can address this gap, yet current models are limited since vertebral endplates are removed to maintain cell viability, physiological loading is not applied, and mechanical behaviors are not measured. This study aimed to (i) establish a method for isolating human IVDs from autopsy with intact vertebral endplates, and (ii) develop and validate an organ culture loading system for human or bovine IVDs. Human IVDs with intact endplates were isolated from cadavers within 48 hours of death and cultured for up to 21 days. IVDs remained viable with ~80% cell viability in nucleus and annulus regions. A dynamic loading system was designed and built with the capacity to culture 9 bovine or 6 human IVDs simultaneously while applying simulated physiologic loads (maximum force: 4kN) and measuring IVD mechanical behaviors. The loading system accurately applied dynamic loading regimes (RMS error <2.5N and total harmonic distortion <2.45%), and precisely evaluated mechanical behavior of rubber and bovine IVDs. Bovine IVDs maintained their mechanical behavior and retained >85% viable cells throughout the 3 week culture period. This organ culture loading system can closely mimic physiological conditions and be used to investigate response of living human and bovine IVDs to mechanical and chemical challenges and to screen therapeutic repair techniques. PMID:24725441

  13. Development and validation of a bioreactor system for dynamic loading and mechanical characterization of whole human intervertebral discs in organ culture.

    PubMed

    Walter, B A; Illien-Jünger, S; Nasser, P R; Hecht, A C; Iatridis, J C

    2014-06-27

    Intervertebral disc (IVD) degeneration is a common cause of back pain, and attempts to develop therapies are frustrated by lack of model systems that mimic the human condition. Human IVD organ culture models can address this gap, yet current models are limited since vertebral endplates are removed to maintain cell viability, physiological loading is not applied, and mechanical behaviors are not measured. This study aimed to (i) establish a method for isolating human IVDs from autopsy with intact vertebral endplates, and (ii) develop and validate an organ culture loading system for human or bovine IVDs. Human IVDs with intact endplates were isolated from cadavers within 48h of death and cultured for up to 21 days. IVDs remained viable with ~80% cell viability in nucleus and annulus regions. A dynamic loading system was designed and built with the capacity to culture 9 bovine or 6 human IVDs simultaneously while applying simulated physiologic loads (maximum force: 4kN) and measuring IVD mechanical behaviors. The loading system accurately applied dynamic loading regimes (RMS error <2.5N and total harmonic distortion <2.45%), and precisely evaluated mechanical behavior of rubber and bovine IVDs. Bovine IVDs maintained their mechanical behavior and retained >85% viable cells throughout the 3 week culture period. This organ culture loading system can closely mimic physiological conditions and be used to investigate response of living human and bovine IVDs to mechanical and chemical challenges and to screen therapeutic repair techniques.

  14. [Polish nomenclature of lumbar disc disease].

    PubMed

    Radło, Paweł; Smetkowski, Andrzej; Tesiorowski, Maciej

    2014-01-01

    Lumbar disc herniation is one of the most common damage of musculoskeletal system. The incidence of pain of lumbosacral spine is estimated approximately on 60-90% in general population, whereas the incidence of disc herniation in patients experiencing low back pain is about 91%. Despite the high incidence and uncomplicated pathogenesis of disc disease there is a problem with the nomenclature. In the vast majority of cases, the naming confusion stems from ignorance of the etiology of low back pain. Different terminologies: morphological, topographical, Radiological and Clinical are used interchangeably. In addition, diagnosis is presented in a variety of languages: Polish, English and Latin. Moreover, the medical and traditional language are used alternately. The authors found in Polish literature more, than 20 terms to describe lumbar disc herniation. All of these terms in the meaning of the authors are used to determine one pathology--mechanical damage to the intervertebral disc and moving the disc material beyond the anatomical area.

  15. Percutaneous Mitral Valve Repair in Mitral Regurgitation Reduces Cell-Free Hemoglobin and Improves Endothelial Function

    PubMed Central

    Rammos, Christos; Zeus, Tobias; Balzer, Jan; Kubatz, Laura; Hendgen-Cotta, Ulrike B.; Veulemans, Verena; Hellhammer, Katharina; Totzeck, Matthias; Luedike, Peter; Kelm, Malte; Rassaf, Tienush

    2016-01-01

    Background and Objective Endothelial dysfunction is predictive for cardiovascular events and may be caused by decreased bioavailability of nitric oxide (NO). NO is scavenged by cell-free hemoglobin with reduction of bioavailable NO up to 70% subsequently deteriorating vascular function. While patients with mitral regurgitation (MR) suffer from an impaired prognosis, mechanisms relating to coexistent vascular dysfunctions have not been described yet. Therapy of MR using a percutaneous mitral valve repair (PMVR) approach has been shown to lead to significant clinical benefits. We here sought to investigate the role of endothelial function in MR and the potential impact of PMVR. Methods and Results Twenty-seven patients with moderate-to-severe MR treated with the MitraClip® device were enrolled in an open-label single-center observational study. Patients underwent clinical assessment, conventional echocardiography, and determination of endothelial function by measuring flow-mediated dilation (FMD) of the brachial artery using high-resolution ultrasound at baseline and at 3-month follow-up. Patients with MR demonstrated decompartmentalized hemoglobin and reduced endothelial function (cell-free plasma hemoglobin in heme 28.9±3.8 μM, FMD 3.9±0.9%). Three months post-procedure, PMVR improved ejection fraction (from 41±3% to 46±3%, p = 0.03) and NYHA functional class (from 3.0±0.1 to 1.9±1.7, p<0.001). PMVR was associated with a decrease in cell free plasma hemoglobin (22.3±2.4 μM, p = 0.02) and improved endothelial functions (FMD 4.8±1.0%, p<0.0001). Conclusion We demonstrate here that plasma from patients with MR contains significant amounts of cell-free hemoglobin, which is accompanied by endothelial dysfunction. PMVR therapy is associated with an improved hemoglobin decompartmentalization and vascular function. PMID:26986059

  16. Echocardiographic Assessment of Degenerative Mitral Stenosis: A Diagnostic Challenge of an Emerging Cardiac Disease.

    PubMed

    Oktay, Ahmet Afşşin; Gilliland, Yvonne E; Lavie, Carl J; Ramee, Stephen J; Parrino, Patrick E; Bates, Michael; Shah, Sangeeta; Cash, Michael E; Dinshaw, Homeyar; Qamruddin, Salima

    2017-03-01

    Degenerative mitral stenosis (DMS) is characterized by decreased mitral valve (MV) orifice area and increased transmitral pressure gradient due to chronic noninflammatory degeneration and subsequent calcification of the fibrous mitral annulus and the MV leaflets. The "true" prevalence of DMS in the general population is unknown. DMS predominantly affects elderly individuals, many of whom have multiple other comorbidities. Transcatheter MV replacement techniques, although their long-term outcomes are yet to be tested, have been gaining popularity and may emerge as more effective and relatively safer treatment option for patients with DMS. Echocardiography is the primary imaging modality for evaluation of DMS and related hemodynamic abnormalities such as increased transmitral pressure gradient and pulmonary arterial pressure. Classic echocardiographic techniques used for evaluation of mitral stenosis (pressure half time, proximal isovelocity surface area, continuity equation, and MV area planimetry) lack validation for DMS. Direct planimetry with 3-dimensional echocardiography and color flow Doppler is a reasonable technique for determining MV area in DMS. Cardiac computed tomography is an essential tool for planning potential interventions or surgeries for DMS. This article reviews the current concepts on mitral annular calcification and its role in DMS. We then discuss the epidemiology, natural history, differential diagnosis, mechanisms, and echocardiographic assessment of DMS.

  17. Tricuspid regurgitation after successful mitral valve surgery.

    PubMed

    Katsi, Vasiliki; Raftopoulos, Leonidas; Aggeli, Constantina; Vlasseros, Ioannis; Felekos, Ioannis; Tousoulis, Dimitrios; Stefanadis, Christodoulos; Kallikazaros, Ioannis

    2012-07-01

    The tricuspid valve (TV) is inseparably connected with the mitral valve (MV) in terms of function. Any pathophysiological condition concerning the MV is potentially a threat for the normal function of the TV as well. One of the most challenging cases is functional tricuspid regurgitation (TR) after surgical MV correction. In the past, TR was considered to progressively revert with time after left-sided valve restoration. Nevertheless, more recent studies showed that TR could develop and evolve postoperatively over time, as well as being closely associated with a poorer prognosis in terms of morbidity and mortality. Pressure and volume overload are usually the underlying pathophysiological mechanisms; structural alterations, like tricuspid annulus dilatation, increased leaflet tethering and right ventricular remodelling are almost always present when regurgitation develops. The most important risk factors associated with a higher probability of late TR development involve the elderly, female gender, larger left atrial size, atrial fibrillation, right chamber dilatation, higher pulmonary artery systolic pressures, longer times from the onset of MV disease to surgery, history of rheumatic heart disease, ischaemic heart disease and prosthetic valve malfunction. The time of TR manifestation can be up to 10 years or more after an MV surgery. Echocardiography, including the novel 3D Echo techniques, is crucial in the early diagnosis and prognosis of future TV disease development. Appropriate surgical technique and timing still need to be clarified.

  18. Tricuspid regurgitation after successful mitral valve surgery

    PubMed Central

    Katsi, Vasiliki; Raftopoulos, Leonidas; Aggeli, Constantina; Vlasseros, Ioannis; Felekos, Ioannis; Tousoulis, Dimitrios; Stefanadis, Christodoulos; Kallikazaros, Ioannis

    2012-01-01

    The tricuspid valve (TV) is inseparably connected with the mitral valve (MV) in terms of function. Any pathophysiological condition concerning the MV is potentially a threat for the normal function of the TV as well. One of the most challenging cases is functional tricuspid regurgitation (TR) after surgical MV correction. In the past, TR was considered to progressively revert with time after left-sided valve restoration. Nevertheless, more recent studies showed that TR could develop and evolve postoperatively over time, as well as being closely associated with a poorer prognosis in terms of morbidity and mortality. Pressure and volume overload are usually the underlying pathophysiological mechanisms; structural alterations, like tricuspid annulus dilatation, increased leaflet tethering and right ventricular remodelling are almost always present when regurgitation develops. The most important risk factors associated with a higher probability of late TR development involve the elderly, female gender, larger left atrial size, atrial fibrillation, right chamber dilatation, higher pulmonary artery systolic pressures, longer times from the onset of MV disease to surgery, history of rheumatic heart disease, ischaemic heart disease and prosthetic valve malfunction. The time of TR manifestation can be up to 10 years or more after an MV surgery. Echocardiography, including the novel 3D Echo techniques, is crucial in the early diagnosis and prognosis of future TV disease development. Appropriate surgical technique and timing still need to be clarified. PMID:22457188

  19. Influence of Tricuspid Bioprosthetic Mitral Valve Orientation Regarding the Flow Field Inside the Left Ventricle: In Vitro Hydrodynamic Characterization Based on 2D PIV Measurements.

    PubMed

    Bazan, Ovandir; Ortiz, Jayme P; Fukumasu, Newton K; Pacifico, Antonio L; Yanagihara, Jurandir I

    2016-02-01

    The flow patterns of a prosthetic heart valve in the aortic or mitral position can change according to its type and orientation. This work describes the use of 2D particle image velocimetry (PIV) applied to the in vitro flow fields characterization inside the upper part of a left ventricular model at various heart rates and as a function of two orientations of stented tricuspid mitral bioprostheses. In the ventricular model, each mitral bioprosthesis (27 and 31 mm diameter) was installed in two orientations, rotated by 180°, while the aortic bileaflet mechanical valve (27 mm diameter) remained in a fixed orientation. The results (N = 50) showed changes in the intraventricular flow fields according to the mitral bioprostheses positioning. Also, changes in the aortic upstream velocity profiles were noticed as a function of mitral orientations.

  20. Minimally invasive, robotic, and off-pump mitral valve surgery.

    PubMed

    Woo, Y Joseph; Rodriguez, Evelio; Atluri, Pavan; Chitwood, W Randolph

    2006-01-01

    A significant transformation is occurring in the management of mitral valve disease. Earlier surgery is now recommended. Mitral valve repair is the standard of care, and newer methods of reconstructing the mitral valve are developing. Surgery with videoscopic assistance can be effectively performed without sternotomy. Robotics systems are gaining wider adoption. Implantable devices to repair or replace the mitral valve off-pump and percutaneously are emerging.

  1. Acute severe mitral regurgitation. Pathophysiology, clinical recognition, and management.

    PubMed

    DePace, N L; Nestico, P F; Morganroth, J

    1985-02-01

    Acute severe mitral regurgitation often goes unrecognized as an emergency requiring prompt, lifesaving treatment. Its causes, physical signs, natural history, echocardiographic features, and findings on chest roentgenography, electrocardiography, and nuclear scintigraphic scanning are reviewed. Acute severe mitral insufficiency can be differentiated from chronic severe mitral insufficiency by noninvasive two-dimensional echocardiography. M-mode echocardiography is a valuable tool in evaluating mitral prosthetic paravalvular regurgitation.

  2. Bioprosthetic mitral valve dysfunction due to native valve preserving procedure.

    PubMed

    Matsuno, Yukihiro; Mori, Yoshio; Umeda, Yukio; Takiya, Hiroshi

    2016-03-01

    Mitral valve replacement with preservation of the mitral leaflets and subvalvular apparatus is considered to maintain left ventricular geometry and function and reduce the risk of myocardial rupture. However, the routine use of this technique may lead to early complications such as left ventricular outflow tract obstruction and even mitral inflow obstruction, requiring reoperation. We describe a rare case of bioprosthetic mitral valve dysfunction caused by a native valve preserving procedure.

  3. Rapidly progressing, massive mitral annular calcification. Occurrence in a patient with chronic renal failure.

    PubMed

    Depace, N L; Rohrer, A H; Kotler, M N; Brezin, J H; Parry, W R

    1981-11-01

    Calcification of the mitral annulus developed in a patient while undergoing dialysis. The rapid onset of events corresponded to the onset of end-stage renal failure and uncontrolled secondary hyperparathyroidism. Sequential echocardiograms verified the progression of calcification of the annulus as well as the valve. A new systolic and diastolic murmur and reduced valve orifice on two-dimensional echocardiography suggested acquired nonrheumatic mitral stenosis and insufficiency. We propose that metastatic calcium deposition rather than long-term hypertensive and degenerative effects was the predominant mechanism for massive calcification of the annulus and valve. It is suggested that M-mode echocardiography be used sequentially to follow both the occurrence and progression of calcification of the mitral annulus or valve in patients with chronic renal failure, secondary hyperparathyroidism, or both.

  4. [Diagnosis and differential therapy of mitral stenosis].

    PubMed

    Fassbender, D; Schmidt, H K; Seggewiss, H; Mannebach, H; Bogunovic, N

    1998-11-01

    Clinical symptoms and diagnostic findings in patients with mitral stenosis are usually determined by the extent of the stenosis. Compared to a normal mitral valve area (MVA) of > 4 cm2, MVA in patients with severe mitral stenosis is usually reduced to < 1.5 cm2. In older patients symptoms are frequently influenced by concomitant diseases (e.g. atrial fibrillation, arterial hypertension or lung disease). An important diagnostic element besides anamnesis, auscultation, ECG and chest X-ray is echocardiography, which is required in order to measure non-invasively and reliably the mitral valve gradient (MVG), the MVA and morphologic changes to the valves, as well as concomitant valvular disease, ventricular functions and, where appropriate, left-atrial thrombi. In addition to the surgical treatment of patients with severe mitral stenosis, which has been an established procedure for 50 years, percutaneous balloon mitral valvuloplasty (MVP) has recently established itself as an alternative option. At the current time, the Inoue technique seems to display the most advantages. Following transseptal puncture, the Inoue balloon is guided transvenously into the left atrium and then into the left ventricle using a special support wire. The balloon is short and soft. Its special unfolding character enables it to be placed securely in the mitral valve without any risk of ventricular perforation (Figure 1). As with surgical commissurotomy, balloon valvuloplasty leads to a separation of fused commissures. This results in a significant reduction of MVG, accompanied by an increase in the MVA (Figure 2). The results and success of MVP are influenced by the morphology of the valves and the changes to the subvalvular apparatus. In randomized studies, the results of surgical commissurotomy were comparable with those of balloon mitral valvulotomy. In our hospital, an increase in MVA from 1.0 to 1.8 cm2 could be achieved in 899 patients (mean age 56 +/- 3 years). In younger patients with

  5. Right Atrial Clot Formation Early after Percutaneous Mitral Balloon Valvuloplasty

    PubMed Central

    Ateş, Ahmet Hakan; Aksakal, Aytekin; Yücel, Huriye; Atasoy Günaydın, İlksen; Ekbul, Adem; Yaman, Mehmet

    2016-01-01

    Mitral balloon valvuloplasty which has been used for the treatment of rheumatic mitral stenosis (MS) for several decades can cause serious complications. Herein, we presented right atrial clot formation early after percutaneous mitral balloon valvuloplasty which was treated successfully with unfractioned heparin infusion. PMID:28105049

  6. Mitral Valve Prolapse in Persons with Down Syndrome.

    ERIC Educational Resources Information Center

    Pueschel, Siegfried M.; Werner, John Christian

    1994-01-01

    Examination of 36 home-reared young adults with Down's syndrome found that 20 had abnormal echocardiographic findings. Thirteen had mitral valve prolapse, three had mitral valve prolapse and aortic insufficiency, two had only aortic insufficiency, and two had other mitral valve disorders. Theories of pathogenesis and relationship to exercise and…

  7. Use of three-dimensional transesophageal echocardiography to evaluate mitral valve morphology for risk stratification prior to mitral valvuloplasty.

    PubMed

    Francis, Loren; Finley, Alan; Hessami, Walead

    2017-02-01

    Mitral stenosis is often managed percutaneously with an interventional procedure such as balloon commissurotomy. Although this often results in an increased mitral valve area and improved clinical symptoms, this procedure is not benign and may have serious complications including the development of hemodynamically significant mitral valve regurgitation. Multiple scoring systems have been developed to attempt to risk stratify these patients prior to their procedure.

  8. Acute mitral regurgitation in Takotsubo cardiomyopathy.

    PubMed

    Bouabdallaoui, Nadia; Wang, Zhen; Lecomte, Milena; Ennezat, Pierre V; Blanchard, Didier

    2015-04-01

    Takotsubo cardiomyopathy (TTC) is a well-recognised entity that commonly manifests with chest pain, ST segment abnormalities and transient left ventricular apical ballooning without coronary artery obstructive disease. This syndrome usually portends a favourable outcome. In the rare haemodynamically unstable TTC patients, acute mitral regurgitation (MR) related to systolic anterior motion (SAM) of the mitral valve and left ventricular outflow tract obstruction (LVOTO) is to be considered. Bedside echocardiography is key in recognition of this latter condition as vasodilators, inotropic agents or intra-aortic balloon counter-pulsation worsen the patient's clinical status. We discuss here a case of TTC where nitrate-induced subaortic obstruction and mitral regurgitation led to haemodynamic instability.

  9. Transcatheter mitral valve implantation: a brief review.

    PubMed

    Mylotte, Darren; Piazza, Nicolo

    2015-09-01

    In the last year transcatheter mitral valve implantation (TMVI) has seen a major jump in development. This technique offers the potential to treat a great number of elderly and/or high-risk patients with severe mitral regurgitation (MR). Such patients are declined surgical intervention either because the institutional Heart Team considers the risk of intervention to exceed the potential benefit, or because the patients and their families believe the morbidity of mitral surgery to be excessive. The advent of a less invasive transcatheter treatment could, therefore, potentially appeal to both clinicians and patients alike. In this overview paper, we describe briefly these recent developments in TVMI technologies as an introduction to the dedicated TVMI technical device parade later in this supplement.

  10. [Interventional mitral valve replacement. Current status].

    PubMed

    Lutter, G; Frank, D

    2016-02-01

    Approximately 30 % of patients suffering from severe valvular heart disease, such as mitral valve regurgitation are non-compliant to the gold standard of minimally invasive surgery, reconstruction or valve replacement. The number of these mostly old patients with severe comorbidities is increasing; therefore, transcatheter interventions have been developed to address an unmet clinical need and may be an alternative therapeutic option to the reference standard. Apart from the successful MitraClip therapy, alternative transcatheter reconstruction technologies are being developed. As with transcatheter aortic valve implantation (TAVI) procedures, the off-pump implantation of a valved stent into the mitral position mainly via a transapical approach will be of great benefit. Recently, the feasibility of transcatheter mitral valved stent implantation in high-risk patients has already been reported.

  11. Mechanical behavior of the human lumbar intervertebral disc with polymeric hydrogel nucleus implant: An experimental and finite element study

    NASA Astrophysics Data System (ADS)

    Joshi, Abhijeet Bhaskar

    The origin of the lower back pain is often the degenerated lumbar intervertebral disc (IVD). We are proposing replacement of the degenerated nucleus by a PVA/PVP polymeric hydrogel implant. We hypothesize that a polymeric hydrogel nucleus implant can restore the normal biomechanics of the denucleated IVD by mimicking the natural load transfer phenomenon as in case of the intact IVD. Lumbar IVDs (n = 15) were harvested from human cadavers. In the first part, specimens were tested in four different conditions for compression: Intact, bone in plug, denucleated and Implanted. Hydrogel nucleus implants were chosen to have line-to-line fit in the created nuclear cavity. In the second part, nucleus implant material (modulus) and geometric (height and diameter) parameters were varied and specimens (n = 9) were tested. Nucleus implants with line-to-line fit significantly restored (88%) the compressive stiffness of the denucleated IVD. The synergistic effect between the implant and the intact annulus resulted in the nonlinear increase in implanted IVD stiffness, where Poisson effect of the hydrogel played major role. Nucleus implant parameters were observed to have a significant effect on the compressive stiffness. All implants with modulus in the tested range restored the compressive stiffness. The undersize implants resulted in incomplete restoration while oversize implants resulted in complete restoration compared to the BI condition. Finite element models (FEM) were developed to simulate the actual test conditions and validated against the experimental results for all conditions. The annulus (defined as hyperelastic, isotropic) mainly determined the nonlinear response of the IVD. Validated FEMs predicted 120--3000 kPa as a feasible range for nucleus implant modulus. FEMs also predicted that overdiameter implant would be more effective than overheight implant in terms of stiffness restoration. Underdiameter implants, initially allowed inward deformation of the annulus and

  12. Mitral valve repair over five decades

    PubMed Central

    2015-01-01

    It has become evident that mitral valve (MV) repair is the preferable treatment for the majority of patients presenting with severe mitral regurgitation (MR). This success clearly testifies that the surgical procedure is accessible, reproducible and is carrying excellent long-lasting results. From the pre-extracorporeal circulation’s era to the last percutaneous approaches, a large variety of techniques have been proposed to address the different features of MV diseases. This article aimed at reviewing chronologically the development of these dedicated techniques through their origins and the debates that they generated in the literature. PMID:26309841

  13. Severe mitral regurgitation due to an extraordinary heart defect.

    PubMed

    García-Ropero, Álvaro; Cortés García, Marcelino; Aldamiz Echevarría, Gonzalo; Farré Muncharaz, Jerónimo

    2016-09-01

    A previously non-described cause of mitral regurgitation is presented. An asymptomatic 50-year old male who was casually diagnosed of mitral valve Barlow's disease underwent cardiac surgery due to severe mitral regurgitation. In the operating theatre, a longitudinal fissure of 1.5-2.0 cm length, along the posterior mitral leaflet, was found responsible for the insufficiency. This defect had features of a potential congenital origin and it was successfully repaired with direct suture. Whether it is an atypical mitral cleft, a variation of Barlow's morphology spectrum or a new congenital heart defect remains unclear.

  14. Additional value of biplane transoesophageal imaging in assessment of mitral valve prostheses.

    PubMed Central

    Groundstroem, K; Rittoo, D; Hoffman, P; Bloomfield, P; Sutherland, G R

    1993-01-01

    OBJECTIVES--To determine whether biplane transoesophageal imaging offers advantages in the evaluation of mitral prostheses when compared with standard single transverse plane imaging or the precordial approach in suspected prosthetic dysfunction. DESIGN--Prospective mitral valve prosthesis in situ using precordial and biplane transoesophageal ultrasonography. SETTING--Tertiary cardiac referral centre. SUBJECTS--67 consecutive patients with suspected dysfunction of a mitral valve prosthesis (16 had bioprostheses and 51 mechanical prostheses) who underwent precordial, transverse plane, and biplane transoesophageal echocardiography. Correlative invasive confirmation from surgery or angiography, or both, was available in 44 patients. MAIN OUTCOME MEASURES--Number, type, and site of leak according to the three means of scanning. RESULTS--Transverse plane transoesophageal imaging alone identified all 31 medial/lateral paravalvar leaks but only 24/30 of the anterior/posterior leaks. Combining the information from both imaging planes confirmed that biplane scanning identified all paravalvar leaks. Five of the six patients with prosthetic valve endocarditis, all three with valvar thrombus or obstruction, and all three with mitral annulus rupture were diagnosed from transverse plane imaging alone. Longitudinal plane imaging alone enabled diagnosis of the remaining case of prosthetic endocarditis and a further case of subvalvar pannus formation. CONCLUSIONS--Transverse plane transoesophageal imaging was superior to the longitudinal imaging in identifying medial and lateral lesions around the sewing ring of a mitral valve prosthesis. Longitudinal plane imaging was superior in identifying anterior and posterior lesions. Biplane imaging is therefore an important development in the study of mitral prosthesis function. Images PMID:8398497

  15. Rapid radiative clearing of protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Haworth, Thomas J.; Clarke, Cathie J.; Owen, James E.

    2016-04-01

    The lack of observed transition discs with inner gas holes of radii greater than ˜50 au implies that protoplanetary discs dispersed from the inside out must remove gas from the outer regions rapidly. We investigate the role of photoevaporation in the final clearing of gas from low mass discs with inner holes. In particular, we study the so-called `thermal sweeping' mechanism which results in rapid clearing of the disc. Thermal sweeping was originally thought to arise when the radial and vertical pressure scalelengths at the X-ray heated inner edge of the disc match. We demonstrate that this criterion is not fundamental. Rather, thermal sweeping occurs when the pressure maximum at the inner edge of the dust heated disc falls below the maximum possible pressure of X-ray heated gas (which depends on the local X-ray flux). We derive new critical peak volume and surface density estimates for rapid radiative clearing which, in general, result in rapid dispersal happening less readily than in previous estimates. This less efficient clearing of discs by X-ray driven thermal sweeping leaves open the issue of what mechanism (e.g. far-ultraviolet heating) can clear gas from the outer disc sufficiently quickly to explain the non-detection of cold gas around weak line T Tauri stars.

  16. Early postpartum mitral valve thrombosis requiring extra corporeal membrane oxygenation before successful valve replacement.

    PubMed

    Halldorsdottir, H; Nordström, J; Brattström, O; Sennström, M M; Sartipy, U; Mattsson, E

    2016-05-01

    Pregnancy is associated with an increased risk of thrombosis in women with mechanical prosthetic heart valves. We present the case of a 29-year-old woman who developed early postpartum mitral valve thrombus after an elective cesarean delivery. The patient had a mechanical mitral valve and was treated with warfarin in the second trimester, which was replaced with high-dose dalteparin during late pregnancy. Elective cesarean delivery was performed under general anesthesia at 37weeks of gestation. The patient was admitted to the intensive care unit for postoperative care and within 30min she developed dyspnea and hypoxia requiring mechanical ventilation. She deteriorated rapidly and developed pulmonary edema, worsening hypoxia and severe acidosis. Urgent extra corporeal membrane oxygenation was initiated. Transesophageal echocardiography revealed a mitral valve thrombus. The patient underwent a successful mitral valve replacement after three days on extra corporeal membrane oxygenation. This case highlights the importance of multidisciplinary care and frequent monitoring of anticoagulation during care of pregnant women with prosthetic heart valves.

  17. Fluid-structure interaction in the left ventricle of the human heart coupled with mitral valve

    NASA Astrophysics Data System (ADS)

    Meschini, Valentina; de Tullio, Marco Donato; Querzoli, Giorgio; Verzicco, Roberto

    2016-11-01

    In this paper Direct Numerical Simulations (DNS), implemented using a fully fluid-structure interaction model for the left ventricle, the mitral valve and the flowing blood, and laboratory experiments are performed in order to cross validate the results. Moreover a parameter affecting the flow dynamics is the presence of a mitral valve. We model two cases, one with a natural mitral valve and another with a prosthetic mechanical one. Our aim is to understand their different effects on the flow inside the left ventricle in order to better investigate the process of valve replacement. We simulate two situations, one of a healthy left ventricle and another of a failing one. While in the first case the flow reaches the apex of the left ventricle and washout the stagnant fluid with both mechanical and natural valve, in the second case the disturbance generated by the mechanical leaflets destabilizes the mitral jet, thus further decreasing its capability to penetrate the ventricular region and originating heart attack or cardiac pathologies in general.

  18. Myocardial Infarction Alters Adaptation of the Tethered Mitral Valve

    PubMed Central

    Dal-Bianco, Jacob P.; Aikawa, Elena; Bischoff, Joyce; Guerrero, J. Luis; Hjortnaes, Jesper; Beaudoin, Jonathan; Szymanski, Catherine; Bartko, Philipp E.; Seybolt, Margo M.; Handschumacher, Mark D.; Sullivan, Suzanne; Garcia, Michael L.; Mauskapf, Adam; Titus, James S.; Wylie-Sears, Jill; Irvin, Whitney S.; Chaput, Miguel; Messas, Emmanuel; Hagège, Albert A.; Carpentier, Alain; Levine, Robert A.

    2016-01-01

    BACKGROUND In patients with myocardial infarction (MI), leaflet tethering by displaced papillary muscles induces mitral regurgitation (MR), which doubles mortality. Mitral valves (MVs) are larger in such patients but fibrosis sets in counterproductively. The investigators previously reported that experimental tethering alone increases mitral valve area in association with endothelial-to-mesenchymal transition. OBJECTIVES This study explored the clinically relevant situation of tethering and MI, testing the hypothesis that ischemic milieu modifies MV adaptation. METHODS Twenty-three adult sheep were examined. Under cardiopulmonary bypass, the PM tips in 6 sheep were retracted apically to replicate tethering, short of producing MR (tethered-alone). PM retraction was combined with apical MI created by coronary ligation in another 6 sheep (tethered + MI), and left ventricular (LV) remodeling was limited by external constraint in 5 additional sheep (LV constraint). Six sham-operated sheep were controls. Diastolic MV surface area was quantified by 3-dimensional echocardiography at baseline and after 58 ± 5 days, followed by histopathology and flow cytometry of excised leaflets. RESULTS Tethered + MI leaflets were markedly thicker than tethered-alone valves and sham controls. Leaflet area also increased significantly. EMT, detected as α-smooth muscle actin-positive endothelial cells, significantly exceeded that in tethered-alone and control valves. Transforming growth factor-β, matrix metalloproteinase expression, and cellular proliferation were markedly increased. Uniquely, tethering + MI showed endothelial activation with vascular adhesion molecule expression, neovascularization, and cells positive for CD45, considered a hematopoietic cell marker. Tethered + MI findings were comparable with external ventricular constraint. CONCLUSIONS MI altered leaflet adaptation, including a profibrotic increase in valvular cell activation, CD45-positive cells, and matrix turnover

  19. Turbine disc sealing assembly

    DOEpatents

    Diakunchak, Ihor S.

    2013-03-05

    A disc seal assembly for use in a turbine engine. The disc seal assembly includes a plurality of outwardly extending sealing flange members that define a plurality of fluid pockets. The sealing flange members define a labyrinth flow path therebetween to limit leakage between a hot gas path and a disc cavity in the turbine engine.

  20. Spontaneous Regression of Herniated Lumbar Disc with New Disc Protrusion in the Adjacent Level

    PubMed Central

    Gürcan, Serkan

    2016-01-01

    Spontaneous regression of herniated lumbar discs was reported occasionally. The mechanisms proposed for regression of disc herniation are still incomplete. This paper describes and discusses a case of spontaneous regression of herniated lumbar discs with a new disc protrusion in the adjacent level. A 41-year-old man was admitted with radiating pain and numbness in the left lower extremity with a left posterolateral disc extrusion at L5-S1 level. He was admitted to hospital with low back pain due to disc herniation caudally immigrating at L4-5 level three years ago. He refused the surgical intervention that was offered and was treated conservatively at that time. He had no neurological deficit and a history of spontaneous regression of the extruded lumbar disc; so, a conservative therapy, including bed rest, physical therapy, nonsteroidal anti-inflammatory drugs, and analgesics, was advised. In conclusion, herniated lumbar disc fragments may regress spontaneously. Reports are prone to advise conservative treatment for extruded or sequestrated lumbar disc herniations. However, these patients should be followed up closely; new herniation at adjacent/different level may occur. Furthermore, it is important to know which herniated disk should be removed and which should be treated conservatively, because disc herniation may cause serious complications as muscle weakness and cauda equine syndrome. PMID:27429818

  1. 3D Printed Modeling of the Mitral Valve for Catheter-Based Structural Interventions.

    PubMed

    Vukicevic, Marija; Puperi, Daniel S; Jane Grande-Allen, K; Little, Stephen H

    2017-02-01

    As catheter-based structural heart interventions become increasingly complex, the ability to effectively model patient-specific valve geometry as well as the potential interaction of an implanted device within that geometry will become increasingly important. Our aim with this investigation was to combine the technologies of high-spatial resolution cardiac imaging, image processing software, and fused multi-material 3D printing, to demonstrate that patient-specific models of the mitral valve apparatus could be created to facilitate functional evaluation of novel trans-catheter mitral valve repair strategies. Clinical 3D transesophageal echocardiography and computed tomography images were acquired for three patients being evaluated for a catheter-based mitral valve repair. Target anatomies were identified, segmented and reconstructed into 3D patient-specific digital models. For each patient, the mitral valve apparatus was digitally reconstructed from a single or fused imaging data set. Using multi-material 3D printing methods, patient-specific anatomic replicas of the mitral valve were created. 3D print materials were selected based on the mechanical testing of elastomeric TangoPlus materials (Stratasys, Eden Prairie, Minnesota, USA) and were compared to freshly harvested porcine leaflet tissue. The effective bending modulus of healthy porcine MV tissue was significantly less than the bending modulus of TangoPlus (p < 0.01). All TangoPlus varieties were less stiff than the maximum tensile elastic modulus of mitral valve tissue (3697.2 ± 385.8 kPa anterior leaflet; 2582.1 ± 374.2 kPa posterior leaflet) (p < 0.01). However, the slopes of the stress-strain toe regions of the mitral valve tissues (532.8 ± 281.9 kPa anterior leaflet; 389.0 ± 156.9 kPa posterior leaflet) were not different than those of the Shore 27, Shore 35, and Shore 27 with Shore 35 blend TangoPlus material (p > 0.95). We have demonstrated that patient-specific mitral valve models can be

  2. Mitral Valve Prolapse in Young Patients.

    ERIC Educational Resources Information Center

    McFaul, Richard C.

    1987-01-01

    A review of research regarding mitral valve prolapse in young children indicates that up to five percent of this population have the condition, with the majority being asymptomatic and requiring reassurance that the condition usually remains mild. Beta-blocking drugs are prescribed for patients with disabling chest pain, dizziness, palpitation, or…

  3. Minimally Invasive Mitral Valve Surgery III

    PubMed Central

    Lehr, Eric J.; Guy, T. Sloane; Smith, Robert L.; Grossi, Eugene A.; Shemin, Richard J.; Rodriguez, Evelio; Ailawadi, Gorav; Agnihotri, Arvind K.; Fayers, Trevor M.; Hargrove, W. Clark; Hummel, Brian W.; Khan, Junaid H.; Malaisrie, S. Chris; Mehall, John R.; Murphy, Douglas A.; Ryan, William H.; Salemi, Arash; Segurola, Romualdo J.; Smith, J. Michael; Wolfe, J. Alan; Weldner, Paul W.; Barnhart, Glenn R.; Goldman, Scott M.; Lewis, Clifton T. P.

    2016-01-01

    Abstract Minimally invasive mitral valve operations are increasingly common in the United States, but robotic-assisted approaches have not been widely adopted for a variety of reasons. This expert opinion reviews the state of the art and defines best practices, training, and techniques for developing a successful robotics program. PMID:27662478

  4. Differential MicroRNA Expression Profile in Myxomatous Mitral Valve Prolapse and Fibroelastic Deficiency Valves.

    PubMed

    Chen, Yei-Tsung; Wang, Juan; Wee, Abby S Y; Yong, Quek-Wei; Tay, Edgar Lik-Wui; Woo, Chin Cheng; Sorokin, Vitaly; Richards, Arthur Mark; Ling, Lieng-Hsi

    2016-05-18

    Myxomatous mitral valve prolapse (MMVP) and fibroelastic deficiency (FED) are two common variants of degenerative mitral valve disease (DMVD), which is a leading cause of mitral regurgitation worldwide. While pathohistological studies have revealed differences in extracellular matrix content in MMVP and FED, the molecular mechanisms underlying these two disease entities remain to be elucidated. By using surgically removed valvular specimens from MMVP and FED patients that were categorized on the basis of echocardiographic, clinical and operative findings, a cluster of microRNAs that expressed differentially were identified. The expressions of has-miR-500, -3174, -17, -1193, -646, -1273e, -4298, -203, -505, and -939 showed significant differences between MMVP and FED after applying Bonferroni correction (p < 0.002174). The possible involvement of microRNAs in the pathogenesis of DMVD were further suggested by the presences of in silico predicted target sites on a number of genes reported to be involved in extracellular matrix homeostasis and marker genes for cellular composition of mitral valves, including decorin (DCN), aggrecan (ACAN), fibromodulin (FMOD), α actin 2 (ACTA2), extracellular matrix protein 2 (ECM2), desmin (DES), endothelial cell specific molecule 1 (ESM1), and platelet/ endothelial cell adhesion molecule 1 (PECAM1), as well as inverse correlations of selected microRNA and mRNA expression in MMVP and FED groups. Our results provide evidence that distinct molecular mechanisms underlie MMVP and FED. Moreover, the microRNAs identified may be targets for the future development of diagnostic biomarkers and therapeutics.

  5. Differential MicroRNA Expression Profile in Myxomatous Mitral Valve Prolapse and Fibroelastic Deficiency Valves

    PubMed Central

    Chen, Yei-Tsung; Wang, Juan; Wee, Abby S. Y.; Yong, Quek-Wei; Tay, Edgar Lik-Wui; Woo, Chin Cheng; Sorokin, Vitaly; Richards, Arthur Mark; Ling, Lieng-Hsi

    2016-01-01

    Myxomatous mitral valve prolapse (MMVP) and fibroelastic deficiency (FED) are two common variants of degenerative mitral valve disease (DMVD), which is a leading cause of mitral regurgitation worldwide. While pathohistological studies have revealed differences in extracellular matrix content in MMVP and FED, the molecular mechanisms underlying these two disease entities remain to be elucidated. By using surgically removed valvular specimens from MMVP and FED patients that were categorized on the basis of echocardiographic, clinical and operative findings, a cluster of microRNAs that expressed differentially were identified. The expressions of has-miR-500, -3174, -17, -1193, -646, -1273e, -4298, -203, -505, and -939 showed significant differences between MMVP and FED after applying Bonferroni correction (p < 0.002174). The possible involvement of microRNAs in the pathogenesis of DMVD were further suggested by the presences of in silico predicted target sites on a number of genes reported to be involved in extracellular matrix homeostasis and marker genes for cellular composition of mitral valves, including decorin (DCN), aggrecan (ACAN), fibromodulin (FMOD), α actin 2 (ACTA2), extracellular matrix protein 2 (ECM2), desmin (DES), endothelial cell specific molecule 1 (ESM1), and platelet/ endothelial cell adhesion molecule 1 (PECAM1), as well as inverse correlations of selected microRNA and mRNA expression in MMVP and FED groups. Our results provide evidence that distinct molecular mechanisms underlie MMVP and FED. Moreover, the microRNAs identified may be targets for the future development of diagnostic biomarkers and therapeutics. PMID:27213335

  6. [Late ventricular potentials and mitral valve prolapse].

    PubMed

    Babuty, D; Charniot, J C; Delhomme, C; Fauchier, L; Fauchier, J P; Cosnay, P

    1994-03-01

    In order to determine the predictive value for ventricular arrhythmias of ventricular late potentials (LP) in mitral valve prolapse (MVP) the authors performed high amplification signal-averaging ECG (SA) and 24 hours ambulatory ECG (Holter) monitoring in 68 consecutive patients (34 men, 34 women, average age 48 +/- 17.7 years) with echocardiographically diagnosed MVP. Patients with bundle branch block or associated cardiac disease were excluded. Echocardiography showed 26 patients to have floppy mitral valves (38.2%), 50 patients to have posterior deplacement > or = 5 mm of the mitral valves in systole (73.5%) and 35 patients to have mitral regurgitation (51.4%). Holter monitoring showed 17 patients without ventricular extrasystoles (VES), 15 had Lown Grade I, 6 had Lown Grade II, 3 had Lown Grade III, 15 had Lown Grade IV A and 12 had Lown Grade IV B ventricular arrhythmias. Therefore, 30 patients had complex ventricular arrhythmias (> or = Lown Grade III) and 13 patients had spontaneous non-sustained ventricular tachycardia (NSVT) (one patient had NSVT on resting ECG but not on Holter monitoring). Eighteen patients had LP (26.5%). The incidence of complex ventricular arrhythmias was higher in patients with mitral regurgitation (62.8% versus 27.7%; p < 0.005) whereas the incidence of NSVT was not significantly different (25.7% versus 17.1%; p = 0.15). On the other hand, the frequency of complex ventricular arrhythmias was not significantly different in the presence or absence of LP (61.1% versus 40%: NS) whereas the incidence of NSVT was higher in patients with LP (44.4% versus 10%; p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Isolated Mitral Cleft in Trisomy 21: An Initially 'Silent' Lesion.

    PubMed

    Thankavel, Poonam P; Ramaciotti, Claudio

    2016-02-01

    Congenital cardiac anomalies are common in trisomy 21, and transthoracic echocardiogram within the first month of life is recommended. While a cleft mitral valve associated with atrioventricular septal defect has been well defined in this population, the prevalence of isolated mitral valve cleft has not been previously reported. The aim of our study was to define the occurrence of isolated mitral cleft in the first echocardiogram of patients with trisomy 21. This retrospective chart review examined echocardiographic data on all Trisomy 21 patients <1 year of age obtained during January 1, 2010, to May 1, 2014, at our institution. Images were reviewed by one of the authors with no knowledge of the official diagnosis. In addition to evaluation for isolated mitral valve cleft, data obtained included presence of additional congenital heart defects and need for surgical intervention. A total of 184 patients (median age 5 days) were identified. Isolated mitral cleft was identified in 12 patients (6.5 %). Four were diagnosed retrospectively (33 %). Only one had mitral regurgitation on initial echocardiogram. Seven required surgery for closure of ventricular septal defects. Isolated mitral cleft is present in an important number of neonates with Trisomy 21. Mitral regurgitation is often absent in the neonatal period and should not be used as a reliable indicator of absence of valve abnormality. Careful attention should be directed toward the mitral valve during the first echocardiogram to exclude an isolated cleft, which can lead to progressive mitral regurgitation.

  8. Echocardiography of congenital mitral valve disorders: echocardiographic-morphological comparisons.

    PubMed

    Silverman, Norman H

    2014-12-01

    I surveyed our echocardiographic database of the years between 1998 and 2012 for congenital abnormalities of the mitral valve in patients over 14 years. A total of 249 patients with mitral valve abnormalities were identified. Abnormalities included clefts in the mitral valve in 58 patients, double orifice of the mitral valve in 19, mitral stenosis with two papillary muscles in 72, and mitral stenosis with one papillary muscle in 51 patients. Supravalvar rings were found in 35 patients with a single papillary muscle, and mitral stenoses with two papillary muscles were found in 22 patients. Mitral prolapse occurred in 44 patients and mitral valvar straddle in five patients. The patients were evaluated by all modalities of ultrasound available over the course of time. Although some lesions were isolated, there were many lesions in which more than one mitral deformity presented in the same patient. The patients are presented showing anatomical correlation with autopsy specimens, some of which came from the patients in this series, and others matched to show correlative anatomy. These lesions remain rare as a group and continue to have high morbidity and mortality.

  9. Mitral valve repair versus replacement in simultaneous aortic and mitral valve surgery

    PubMed Central

    Urban, Marian; Pirk, Jan; Szarszoi, Ondrej; Skalsky, Ivo; Maly, Jiri; Netuka, Ivan

    2013-01-01

    BACKGROUND: Double valve replacement for concomitant aortic and mitral valve disease is associated with substantial morbidity and mortality. Excellent results with valve repair in isolated mitral valve lesions have been reported; therefore, whether its potential benefits would translate into better outcomes in patients with combined mitral-aortic disease was investigated. METHODS: A retrospective observational study was performed involving 341 patients who underwent aortic valve replacement with either mitral valve repair (n=42) or double valve replacement (n=299). Data were analyzed for early mortality, late valve-related complications and survival. RESULTS: The early mortality rate was 11.9% for valve repair and 11.0% for replacement (P=0.797). Survival (± SD) was 67±11% in mitral valve repair with aortic valve replacement and 81±3% in double valve replacement at five years of follow-up (P=0.187). The percentage of patients who did not experience major adverse valve-related events at five years of follow-up was 83±9% in those who underwent mitral valve repair with aortic valve replacement and 89±2% in patients who underwent double valve replacement (P=0.412). Age >70 years (HR 2.4 [95% CI 1.1 to 4.9]; P=0.023) and renal dysfunction (HR 1.9 [95% CI 1.2 to 3.7]; P=0.01) were independent predictors of decreased survival. CONCLUSIONS: In patients with double valve disease, both mitral valve repair and replacement provided comparable early outcomes. There were no significant differences in valve-related reoperations, anticoagulation-related complications or prosthetic valve endocarditis. Patient-related factors appear to be the major determinant of late survival, irrespective of the type of operation. PMID:24294032

  10. Mitral annulus morphologic and functional analysis using real time tridimensional echocardiography in patients submitted to unsupported mitral valve repair

    PubMed Central

    Guedes, Marco Antônio Vieira; Pomerantzeff, Pablo Maria Alberto; Brandão, Carlos Manuel de Almeida; Vieira, Marcelo Luiz Campos; Tarasoutchi, Flávio; Spinola, Pablo da Cunha; Jatene, Fábio Biscegli

    2015-01-01

    Introduction Mitral valve repair is the treatment of choice to correct mitral insufficiency, although the literature related to mitral valve annulus behavior after mitral repair without use of prosthetic rings is scarce. Objective To analyze mitral annulus morphology and function using real time tridimensional echocardiography in individuals submitted to mitral valve repair with Double Teflon technique. Methods Fourteen patients with mitral valve insufficiency secondary to mixomatous degeneration that were submitted to mitral valve repair with the Double Teflon technique were included. Thirteen patients were in FC III/IV. Patients were evaluated in preoperative period, immediate postoperative period, 6 months and 1 year after mitral repair. Statistical analysis was made by repeated measures ANOVA test and was considered statistically significant P<0.05. Results There were no deaths, reoperation due to valve dysfunction, thromboembolism or endocarditis during the study. Posterior mitral annulus demonstrated a significant reduction in immediate postoperative period (P<0.001), remaining stable during the study, and presents a mean of reduction of 25.8% comparing with preoperative period. There was a significant reduction in anteroposterior and mediolateral diameters in the immediate postoperative period (P<0.001), although there was a significant increase in mediolateral diameter between immediate postoperative period and 1 year. There was no difference in mitral internal area variation over the cardiac cycle during the study. Conclusion Segmentar annuloplasty reduced the posterior component of mitral annulus, which remained stable in a 1-year-period. The variation in mitral annulus area during cardiac cycle remained stable during the study. PMID:26313723

  11. Asymptotic Model of Fluid-Tissue Interaction for Mitral Valve Dynamics.

    PubMed

    Domenichini, Federico; Pedrizzetti, Gianni

    2015-06-01

    The vortex formation process inside the left ventricle is intrinsically connected to the dynamics of the mitral leaflets while they interact with the flow crossing the valve during diastole. The description of the dynamics of a natural mitral valve still represents a challenging issue, especially because its material properties are not measurable in vivo. Medical imaging can provide some indications about the geometry of the valve, but not about its mechanical properties. In this work, we introduce a parametric model of the mitral valve geometry, whose motion is described in the asymptotic limit under the assumption that it moves with the flow, without any additional resistance other than that given by its shape, and without the need to specify its material properties. The mitral valve model is coupled with a simple description of the left ventricle geometry, and their dynamics is solved numerically together with the equations ruling the blood flow. The intra-ventricular flow is analyzed in its relationship with the valvular motion. It is found that the initial valve opening anticipates the peak velocity of the Early filling wave with little influence of the specific geometry; while subsequent closure and re-opening are more dependent on the intraventricular vortex dynamics and thus on the leaflets' geometry itself. The limitations and potential applications of the proposed model are discussed.

  12. TexMi: Development of Tissue-Engineered Textile-Reinforced Mitral Valve Prosthesis

    PubMed Central

    Moreira, Ricardo; Gesche, Valentine N.; Hurtado-Aguilar, Luis G.; Schmitz-Rode, Thomas; Frese, Julia

    2014-01-01

    Mitral valve regurgitation together with aortic stenosis is the most common valvular heart disease in Europe and North America. Mechanical and biological prostheses available for mitral valve replacement have significant limitations such as the need of a long-term anticoagulation therapy and failure by calcifications. Both types are unable to remodel, self-repair, and adapt to the changing hemodynamic conditions. Moreover, they are mostly designed for the aortic position and do not reproduce the native annular-ventricular continuity, resulting in suboptimal hemodynamics, limited durability, and gradually decreasing ventricular pumping efficiency. A tissue-engineered heart valve specifically designed for the mitral position has the potential to overcome the limitations of the commercially available substitutes. For this purpose, we developed the TexMi, a living textile-reinforced mitral valve, which recapitulates the key elements of the native one: annulus, asymmetric leaflets (anterior and posterior), and chordae tendineae to maintain the native annular-ventricular continuity. The tissue-engineered valve is based on a composite scaffold consisting of the fibrin gel as a cell carrier and a textile tubular structure with the twofold task of defining the gross three-dimensional (3D) geometry of the valve and conferring mechanical stability. The TexMi valves were molded with ovine umbilical vein cells and stimulated under dynamic conditions for 21 days in a custom-made bioreactor. Histological and immunohistological stainings showed remarkable tissue development with abundant aligned collagen fibers and elastin deposition. No cell-mediated tissue contraction occurred. This study presents the proof-of-principle for the realization of a tissue-engineered mitral valve with a simple and reliable injection molding process readily adaptable to the patient's anatomy and pathological situation by producing a patient-specific rapid prototyped mold. PMID:24665896

  13. Cell transplantation in lumbar spine disc degeneration disease.

    PubMed

    Hohaus, C; Ganey, T M; Minkus, Y; Meisel, H J

    2008-12-01

    Low back pain is an extremely common symptom, affecting nearly three-quarters of the population sometime in their life. Given that disc herniation is thought to be an extension of progressive disc degeneration that attends the normal aging process, seeking an effective therapy that staves off disc degeneration has been considered a logical attempt to reduce back pain. The most apparent cellular and biochemical changes attributable to degeneration include a decrease in cell density in the disc that is accompanied by a reduction in synthesis of cartilage-specific extracellular matrix components. With this in mind, one therapeutic strategy would be to replace, regenerate, or augment the intervertebral disc cell population, with a goal of correcting matrix insufficiencies and restoring normal segment biomechanics. Biological restoration through the use of autologous disc chondrocyte transplantation offers a potential to achieve functional integration of disc metabolism and mechanics. We designed an animal study using the dog as our model to investigate this hypothesis by transplantation of autologous disc-derived chondrocytes into degenerated intervertebral discs. As a result we demonstrated that disc cells remained viable after transplantation; transplanted disc cells produced an extracellular matrix that contained components similar to normal intervertebral disc tissue; a statistically significant correlation between transplanting cells and retention of disc height could displayed. Following these results the Euro Disc Randomized Trial was initiated to embrace a representative patient group with persistent symptoms that had not responded to conservative treatment where an indication for surgical treatment was given. In the interim analyses we evaluated that patients who received autologous disc cell transplantation had greater pain reduction at 2 years compared with patients who did not receive cells following their discectomy surgery and discs in patients that

  14. Role of Imaging Techniques in Percutaneous Treatment of Mitral Regurgitation.

    PubMed

    Li, Chi-Hion; Arzamendi, Dabit; Carreras, Francesc

    2016-04-01

    Mitral regurgitation is the most prevalent valvular heart disease in the United States and the second most prevalent in Europe. Patients with severe mitral regurgitation have a poor prognosis with medical therapy once they become symptomatic or develop signs of significant cardiac dysfunction. However, as many as half of these patients are inoperable because of advanced age, ventricular dysfunction, or other comorbidities. Studies have shown that surgery increases survival in patients with organic mitral regurgitation due to valve prolapse but has no clinical benefit in those with functional mitral regurgitation. In this scenario, percutaneous repair for mitral regurgitation in native valves provides alternative management of valvular heart disease in patients at high surgical risk. Percutaneous repair for mitral regurgitation is a growing field that relies heavily on imaging techniques to diagnose functional anatomy and guide repair procedures.

  15. Ultrasound based mitral valve annulus tracking for off-pump beating heart mitral valve repair

    NASA Astrophysics Data System (ADS)

    Li, Feng P.; Rajchl, Martin; Moore, John; Peters, Terry M.

    2014-03-01

    Mitral regurgitation (MR) occurs when the mitral valve cannot close properly during systole. The NeoChordtool aims to repair MR by implanting artificial chordae tendineae on flail leaflets inside the beating heart, without a cardiopulmonary bypass. Image guidance is crucial for such a procedure due to the lack of direct vision of the targets or instruments. While this procedure is currently guided solely by transesophageal echocardiography (TEE), our previous work has demonstrated that guidance safety and efficiency can be significantly improved by employing augmented virtuality to provide virtual presentation of mitral valve annulus (MVA) and tools integrated with real time ultrasound image data. However, real-time mitral annulus tracking remains a challenge. In this paper, we describe an image-based approach to rapidly track MVA points on 2D/biplane TEE images. This approach is composed of two components: an image-based phasing component identifying images at optimal cardiac phases for tracking, and a registration component updating the coordinates of MVA points. Preliminary validation has been performed on porcine data with an average difference between manually and automatically identified MVA points of 2.5mm. Using a parallelized implementation, this approach is able to track the mitral valve at up to 10 images per second.

  16. Mitral valve repair for ischemic mitral regurgitation: lessons from the Cardiothoracic Surgical Trials Network randomized study.

    PubMed

    Mihos, Christos G; Santana, Orlando

    2016-01-01

    Approximately 30% to 50% of patients will develop ischemic mitral regurgitation (MR) after a myocardial infarction, which is a result of progressive left ventricular remodeling and dysfunction of the subvalvular apparatus, and portends a poor long-term prognosis. Surgical treatment is centered on mitral valve repair utilizing a restrictive annuloplasty, or valve replacement with preservation of the subvalvular apparatus. In the recent Cardiothoracic Surgical Trials Network (CSTN) study, patients with severe ischemic MR were randomized to mitral valve repair with a restrictive annuloplasty versus chordal-sparing valve replacement, and concomitant coronary artery bypass grafting, if indicated. At 2-year follow-up, mitral valve repair was associated with a significantly higher incidence of moderate or greater recurrent MR and heart failure, with no difference in the indices of left ventricular reverse remodeling, as compared with valve replacement. The current appraisal aims to provide insight into the CSTN trial results, and discusses the evidence supporting a pathophysiologic-guided repair strategy incorporating combined annuloplasty and subvalvular repair techniques to optimize the outcomes of mitral valve repair in ischemic MR.

  17. En face view of the mitral valve: definition and acquisition.

    PubMed

    Mahmood, Feroze; Warraich, Haider Javed; Shahul, Sajid; Qazi, Aisha; Swaminathan, Madhav; Mackensen, G Burkhard; Panzica, Peter; Maslow, Andrew

    2012-10-01

    A 3-dimensional echocardiographic view of the mitral valve, called the "en face" or "surgical view," presents a view of the mitral valve similar to that seen by the surgeon from a left atrial perspective. Although the anatomical landmarks of this view are well defined, no comprehensive echocardiographic definition has been presented. After reviewing the literature, we provide a definition of the left atrial and left ventricular en face views of the mitral valve. Techniques used to acquire this view are also discussed.

  18. Evolution of the concept and practice of mitral valve repair

    PubMed Central

    Tchantchaleishvili, Vakhtang; Rajab, Taufiek K.

    2015-01-01

    The first successful mitral valve repair was performed by Elliot Cutler at Brigham and Women’s Hospital in 1923. Subsequent evolution in the surgical techniques as well as multi-disciplinary cooperation between cardiac surgeons, cardiologists and cardiac anesthesiologists has resulted in excellent outcomes. In spite of this, the etiology of mitral valve pathology ultimately determines the outcome of mitral valve repair. PMID:26309840

  19. Finite element analysis to model complex mitral valve repair.

    PubMed

    Labrosse, Michel; Mesana, Thierry; Baxter, Ian; Chan, Vincent

    2016-01-01

    Although finite element analysis has been used to model simple mitral repair, it has not been used to model complex repair. A virtual mitral valve model was successful in simulating normal and abnormal valve function. Models were then developed to simulate an edge-to-edge repair and repair employing quadrangular resection. Stress contour plots demonstrated increased stresses along the mitral annulus, corresponding to the annuloplasty. The role of finite element analysis in guiding clinical practice remains undetermined.

  20. Acute aortic and mitral valve regurgitation following blunt chest trauma.

    PubMed

    Bernabeu, Eduardo; Mestres, Carlos A; Loma-Osorio, Pablo; Josa, Miguel

    2004-03-01

    Traumatic rupture of intracardiac structures is an uncommon phenomenon although there are a number of reports with regards to rupture of the tricuspid, mitral and aortic valves. We report the case of a 25-year-old patient who presented with acute aortic and mitral valve regurgitation of traumatic origin. Both lesions were seen separated by 2 weeks. Pathophysiology is reviewed. The combination of both aortic and mitral lesions following blunt chest trauma is almost exceptional.

  1. Effect of the mitral valve on diastolic flow patterns

    SciTech Connect

    Seo, Jung Hee; Vedula, Vijay; Mittal, Rajat; Abraham, Theodore; Dawoud, Fady; Luo, Hongchang; Lardo, Albert C.

    2014-12-15

    The leaflets of the mitral valve interact with the mitral jet and significantly impact diastolic flow patterns, but the effect of mitral valve morphology and kinematics on diastolic flow and its implications for left ventricular function have not been clearly delineated. In the present study, we employ computational hemodynamic simulations to understand the effect of mitral valve leaflets on diastolic flow. A computational model of the left ventricle is constructed based on a high-resolution contrast computed-tomography scan, and a physiological inspired model of the mitral valve leaflets is synthesized from morphological and echocardiographic data. Simulations are performed with a diode type valve model as well as the physiological mitral valve model in order to delineate the effect of mitral-valve leaflets on the intraventricular flow. The study suggests that a normal physiological mitral valve promotes the formation of a circulatory (or “looped”) flow pattern in the ventricle. The mitral valve leaflets also increase the strength of the apical flow, thereby enhancing apical washout and mixing of ventricular blood. The implications of these findings on ventricular function as well as ventricular flow models are discussed.

  2. Peri-procedural imaging for transcatheter mitral valve replacement

    PubMed Central

    Natarajan, Navin; Patel, Parag; Bartel, Thomas; Kapadia, Samir; Navia, Jose; Stewart, William; Tuzcu, E. Murat

    2016-01-01

    Mitral regurgitation (MR) has a high prevalence in older patient populations of industrialized nations. Common etiologies are structural, degenerative MR and functional MR secondary to myocardial remodeling. Because of co-morbidities and associated high surgical risk, open surgical mitral repair/replacement is deferred in a significant percentage of patients. For these patients transcatheter repair/replacement are emerging as treatment options. Because of the lack of direct visualization, pre- and intra-procedural imaging is critical for these procedures. In this review, we summarize mitral valve anatomy, trans-catheter mitral valve replacement (TMVR) options, and imaging in the context of TMVR. PMID:27054104

  3. Mitral and tricuspid valve surgery for Coffin-Lowry syndrome.

    PubMed

    Yoshida, Takeshi; Ohashi, Takeki; Furui, Masato; Kageyama, Souichirou; Kodani, Noriko; Kobayashi, Yutaka; Hirai, Yasutaka; Sakakura, Reo

    2015-05-01

    Coffin-Lowry syndrome is a rare X-linked disorder characterized by craniofacial and skeletal abnormalities, mental retardation, short stature, and hypotonia. An 18-year-old man with morphologic features characteristic of Coffin-Lowry syndrome was referred to our institution for valve disease surgery for worsening cardiac failure. Echocardiography showed severe mitral valve regurgitation associated with tricuspid valve regurgitation. Mitral valve implantation with a biological valve and tricuspid annular plication with a ring was performed. The ascending aorta was hypoplastic. Both the mitral papillary muscle originating near the mitral annulus and the chordae were shortened. The patient's postoperative course was uneventful and his cardiac failure improved.

  4. Robotic-assisted mitral valve repair: surgical technique.

    PubMed

    Algarni, Khaled D; Suri, Rakesh M; Daly, Richard C

    2014-01-01

    Robotic-assisted mitral valve repair represents the least invasive surgical approach currently available for anatomical mitral valve repair in patients with myxomatous mitral valve disease. Standard mitral valve repair techniques utilized during conventional sternotomy/right thoracotomy are exactly replicated with the robotic instrumentation through 1-2 cm port-like incisions with superior 3D visualization. This is performed on cardiopulmonary bypass by peripheral cannulation of the femoral vessels/right internal jugular vein. The ascending aorta is occluded with a transthoracic aortic cross-clamp. Antegrade cardioplegia is delivered centrally into the aortic root through a cardioplegia vent catheter. By replicating conventional mitral valve repair done via an open sternotomy approach, the quality of mitral valve repair is ensured while providing the patients with advantages of less invasive surgery including shorter hospital stay, rapid recovery and return to normal activities, less blood transfusion, superior cosmesis and complete elimination of sternotomy-related morbidities such as deep sternal wound infection and sternal dehiscence. We reviewed the first consecutive 200 patients undergoing robotic mitral valve repair at Mayo Clinic Rochester between 24 January 2008 and 28 January 2011. Successful mitral valve repair was completed in all patients. There were no early (30-day) deaths. One patient suffered a stroke (0.5%). One patient required reoperation for bleeding (0.5%). Two patients (1%) required reoperation for recurrent mitral regurgitation. Twelve patients (6%) required transfusion of allogeneic blood products. We have noted a significant reduction in operative times and resource utilization over time.

  5. Transcatheter Mitral Valve Repair Therapies: Evolution, Status and Challenges.

    PubMed

    Espiritu, Daniella; Onohara, Daisuke; Kalra, Kanika; Sarin, Eric L; Padala, Muralidhar

    2017-02-01

    Mitral regurgitation is a common cardiac valve lesion, developing from primary lesions of the mitral valve or secondary to cardiomyopathies. Moderate or higher severity of mitral regurgitation imposes significant volume overload on the left ventricle, causing permanent structural and functional deterioration of the myocardium and heart failure. Timely correction of regurgitation is essential to preserve cardiac function, but surgical mitral valve repair is often delayed due to the risks of open heart surgery. Since correction of mitral regurgitation can provide symptomatic relief and halt progressive cardiac dysfunction, transcatheter mitral valve repair technologies are emerging as alternative therapies. In this approach, the mitral valve is repaired either with sutures or implants that are delivered to the native valve on catheters introduced into the cardiovascular system under image guidance, through small vascular or ventricular ports. Several transcatheter mitral valve technologies are in development, but limited clinical success has been achieved. In this review, we present a historical perspective of mitral valve repair, review the transcatheter technologies emerging from surgical concepts, the challenges they face in achieving successful clinical application, and the increasing rigor of safety and durability standards for new transcatheter valve technologies.

  6. Chimney technique for mitral valve replacement in children.

    PubMed

    González Rocafort, Álvaro; Aroca, Ángel; Polo, Luz; Rey, Juvenal; Villagrá, Fernando

    2013-11-01

    Severe mitral stenosis is unusual in children, but it represents an important challenge for surgeons because of the scarcity of solutions. Several mitral percutaneous and surgical valvuloplasties are performed repetitively to delay mitral valve replacement. Most of the time these procedures show discouraging results. When mitral valve replacement is performed, the annulus may not be large enough to fit a substitute. We present, to our best knowledge, a new technique to implant a large prosthesis in a small annulus without negatively affecting the opening of the leaflets.

  7. Staphylococcus caprae native mitral valve infective endocarditis

    PubMed Central

    Poyner, Jennifer; Olson, Ewan; Henriksen, Peter; Koch, Oliver

    2016-01-01

    Introduction: Staphylococcus caprae is a rare cause of infective endocarditis. Here, we report a case involving the native mitral valve in the absence of an implantable cardiac electronic device. Case presentation: A 76-year-old man presented with a 2 week history of confusion and pyrexia. His past medical history included an open reduction and internal fixation of a humeral fracture 17 years previously, which remained non-united despite further revision 4 years later. There was no history of immunocompromise or farm-animal contact. Two sets of blood culture bottles, more than 12 h apart, were positive for S. caprae. Trans-thoracic echocardiography revealed a 1×1.2 cm vegetation on the mitral valve, with moderate mitral regurgitation. Due to ongoing confusion, he had a magnetic resonance imaging brain scan, which showed a subacute small vessel infarct consistent with a thromboembolic source. A humeral SPECT-CT (single-photon emission computerized tomography-computerized tomography) scan showed no clear evidence of acute osteomyelitis. Surgical vegetectomy and mitral-valve repair were considered to reduce the risk of further systemic embolism and progressive valve infection. However, the potential risks of surgery to this patient led to a decision to pursue a cure with antibiotic therapy alone. He remained well 3 months after discharge, with repeat echocardiography demonstrating a reduction in the size of the vegetation (0.9 cm). Conclusion: Management of this infection was challenging due to its rarity and its unclear progression, complicated by the dilemma surrounding surgical intervention in a patient with a complex medical background. PMID:28348787

  8. Cardiac pathology after valve replacement by disc prosthesis. A study of 61 necropsy patients.

    PubMed

    Roberts, W C; Fishbein, M C; Golden, A

    1975-05-01

    Clinical and necropsy observations are described in 61 patients who had one or more cardiac valves replaced with a discoid prosthesis of the Hufnagel type. The most common (31 percent) cause of death among the 45 patients who died early (less than 65 days after operation) appeared to be prosthetic disproportion; that is, the prothesis was too big for the aorta or ventricular cavity into which it was inserted so that inadequate space was present between the margins of the disc and the endocardium of ventricle or intima of aorta. Prosthetic thrombosis occurred in only 3 of the 45 patients who died early, but poppet movement appeared considerably altered in each. In contrast, thrombi were observed on a prosthesis in 14 of the 16 patients who died late (4 to 47 months [average 21] postoperatively), but in none did the thrombi appear of sufficient size to alter poppet function. Escessive bleeding occurred in 11 (24 percent) of the 45 early deaths and was primarily related to the insertion of a patch in the root of the aorta. Uncorrected valvular disease either by itself or by its ability to alter function of the prosthesis appeared responsible for death in 6 (13 percent) of the 45 patients who died early and in 2 (6 percent) of the 16 who died late. Insertion of a mitral poppet disc in a patient with uncorrected aortic regurgitation, even of mild degree, may be hazardous because the aortic regurgitant jet stream may interfere with proper function of the mitral disc. Likewise, insertion of a poppet disc only in the aortic valve position in a patient with combined aortic and mitral regurgitation may considerably increase the degree of mitral incompetence because the aortic prosthesis is intrinsically obstructive. Disc wear or variance was observed in all but one prosthesis in place for more than 1 year. Although hemolytic anemia of significant degree was not observed in any of the 16 patients who died late, the occurrence of renal hemosiderosis in 13 of the 16 patients

  9. Preservation versus non-preservation of mitral valve apparatus during mitral valve replacement: a meta-analysis of 3835 patients

    PubMed Central

    Sá, Michel Pompeu Barros de Oliveira; Ferraz, Paulo Ernando; Escobar, Rodrigo Renda; Martins, Wendell Santos; de Araújo e Sá, Frederico Browne Correia; Lustosa, Pablo César; Vasconcelos, Frederico Pires; Lima, Ricardo Carvalho

    2012-01-01

    Resection of the chordopapillary apparatus during mitral valve replacement has been associated with a negative impact on survival. Mitral valve replacement with the preservation of the mitral valve apparatus has been associated with better outcomes, but surgeons remain refractory to its use. To determine if there is any real difference in preservation vs non-preservation of mitral valve apparatus during mitral valve replacement in terms of outcomes, we performed a systematic review and meta-analysis using MEDLINE, EMBASE, CENTRAL/CCTR, SciELO, LILACS, Google Scholar and reference lists of relevant articles to search for clinical studies that compared outcomes (30-day mortality, postoperative low cardiac output syndrome or 5-year mortality) between preservation vs non-preservation during mitral valve replacement from 1966 to 2011. The principal summary measures were odds ratios (ORs) with 95% confidence interval and P-values (that will be considered statistically significant when <0.05). The ORs were combined across studies using a weighted DerSimonian–Laird random-effects model. The meta-analysis was completed using the software Comprehensive Meta-Analysis version 2 (Biostat Inc., Englewood, NJ, USA). Twenty studies (3 randomized and 17 non-randomized) were identified and included a total of 3835 patients (1918 for mitral valve replacement preservation and 1917 for mitral valve replacement non-preservation). There was significant difference between mitral valve replacement preservation and mitral valve replacement non-preservation groups in the risk of 30-day mortality (OR 0.418, P <0.001), postoperative low cardiac output syndrome (OR 0.299, P <0.001) or 5-year mortality (OR 0.380, P <0.001). No publication bias or important heterogeneity of effects on any outcome was observed. In conclusion, we found evidence that argues in favour of the preservation of mitral valve apparatus during mitral valve replacement. PMID:23027596

  10. Dipper discs not inclined towards edge-on orbits

    NASA Astrophysics Data System (ADS)

    Ansdell, M.; Gaidos, E.; Williams, J. P.; Kennedy, G.; Wyatt, M. C.; LaCourse, D. M.; Jacobs, T. L.; Mann, A. W.

    2016-10-01

    The so-called dipper stars host circumstellar discs and have optical and infrared light curves that exhibit quasi-periodic or aperiodic dimming events consistent with extinction by transiting dusty structures orbiting in the inner disc. Most of the proposed mechanisms explaining the dips - i.e. occulting disc warps, vortices, and forming planetesimals - assume nearly edge-on viewing geometries. However, our analysis of the three known dippers with publicly available resolved sub-mm data reveals discs with a range of inclinations, most notably the face-on transition disc J1604-2130 (EPIC 204638512). This suggests that nearly edge-on viewing geometries are not a defining characteristic of the dippers and that additional models should be explored. If confirmed by further observations of more dippers, this would point to inner disc processes that regularly produce dusty structures far above the outer disc mid-plane in regions relevant to planet formation.

  11. Myocardial deformation and rotational profiles in mitral valve prolapse.

    PubMed

    Zito, Concetta; Carerj, Scipione; Todaro, Maria Chiara; Cusmà-Piccione, Maurizio; Caprino, Alessandra; Di Bella, Gianluca; Oreto, Lilia; Oreto, Giuseppe; Khandheria, Bijoy K

    2013-10-01

    We studied whether evaluation of overall left ventricular (LV) and left atrial (LA) mechanics would be useful to detect subclinical dysfunction in patients with mitral valve prolapse (MVP), mitral regurgitation (MR), and normal LV ejection fraction (EF). Fifty consecutive patients (27 men, mean age 61 ± 19 years) with MVP, MR, and normal systolic function (LVEF ≥60%) were prospectively enrolled and compared with 40 age- and gender-matched healthy subjects (22 men, mean age: 59 ± 16 years). At baseline, 2-dimensional and color-flow Doppler transthoracic echocardiography were performed for MR quantification and analysis of left-chambers mechanics. Patients were divided into groups by severity of MR: mild (n = 14), moderate (n = 19), and severe (n = 17). Left ventricular dimensions, volume and mass, and LA area and volume indices were significantly increased in patients with moderate and severe MR compared with control subjects. Circumferential strain, basal/apical rotations, and twist were significantly enhanced in patients with moderate MR compared with controls; with the exception of basal rotation, they decreased in those with severe MR. Furthermore, LA strain and untwisting rate were progressively and significantly reduced from normal subjects to patients with severe MR. Effective regurgitant orifice area and MR vena contracta were significantly related to most systolic and diastolic function parameters and LA volume as well as LA strain and LV untwisting rate in all patients. In conclusion, cardiac mechanics indices, particularly LA deformation and LV rotational parameters, could help unmask incipient myocardial dysfunction in patients with MVP, especially in those with severe MR and yet normal LVEF.

  12. Nonresectional Single-Suture Leaflet Remodeling for Degenerative Mitral Regurgitation Facilitates Minimally Invasive Mitral Valve Repair

    PubMed Central

    MacArthur, John W.; Cohen, Jeffrey E.; Goldstone, Andrew B.; Fairman, Alexander S.; Edwards, Bryan B.; Hornick, Matthew A.; Atluri, Pavan; Woo, Y. Joseph

    2014-01-01

    Background Both leaflet resection and neochordal construction are effective mitral repair techniques, but they may become incrementally time-consuming when using minimally invasive approaches. We have used a single-suture leaflet-remodeling technique of inverting the prolapsed or flail segment tissue into the left ventricle. This repair is straightforward, expeditious, and facilitates a minimally invasive approach. Methods Ninety-nine patients with degenerative mitral regurgitation (MR) underwent a minimally invasive single-suture repair of the mitral valve from May 2007 through December 2012. Preoperative and perioperative echocardiograms as well as patient outcomes were analyzed and compared with those obtained from patients undergoing minimally invasive mitral valve repair using quadrangular resection at the same institution during the same period. Results All 99 patients had a successful mitral repair through a sternal-sparing minimally invasive approach. Ninety-one of the 99 patients had zero MR on postoperative echocardiogram, and 8 of 99 had trace to mild MR. Patients in the nonresectional group had significantly shorter cardiopulmonary bypass and cross-clamp times compared with the quadrangular resection group (115.8 ± 41.7 minutes versus 144.9 ± 38.2 minutes; p < 0.001; 76.2 ± 28.1 minutes versus 112.6 ± 33.5 minutes; p < 0.001, respectively). The mean length of stay was 7.5 ± 3 days. All patients were discharged alive and free from clinical symptoms of MR. There have been no reoperations for recurrent MR on subsequent average follow-up of 1 year. Conclusions An effective, highly efficient, and thus far durable single-suture mitral leaflet-remodeling technique facilitates minimally invasive repair of degenerative MR. PMID:23932318

  13. Fluid–Structure Interaction Analysis of Papillary Muscle Forces Using a Comprehensive Mitral Valve Model with 3D Chordal Structure

    SciTech Connect

    Toma, Milan; Jensen, Morten Ø.; Einstein, Daniel R.; Yoganathan, Ajit P.; Cochran, Richard P.; Kunzelman, Karyn S.

    2015-07-17

    Numerical models of native heart valves are being used to study valve biomechanics to aid design and development of repair procedures and replacement devices. These models have evolved from simple two-dimensional approximations to complex three-dimensional, fully coupled fluid-structure interaction (FSI) systems. Such simulations are useful for predicting the mechanical and hemodynamic loading on implanted valve devices. A current challenge for improving the accuracy of these predictions is choosing and implementing modeling boundary conditions. In order to address this challenge, we are utilizing an advanced in-vitro system to validate FSI conditions for the mitral valve system. Explanted ovine mitral valves were mounted in an in vitro setup, and structural data for the mitral valve was acquired with *CT. Experimental data from the in-vitro ovine mitral valve system were used to validate the computational model. As the valve closes, the hemodynamic data, high speed lea et dynamics, and force vectors from the in-vitro system were compared to the results of the FSI simulation computational model. The total force of 2.6 N per papillary muscle is matched by the computational model. In vitro and in vivo force measurements are important in validating and adjusting material parameters in computational models. The simulations can then be used to answer questions that are otherwise not possible to investigate experimentally. This work is important to maximize the validity of computational models of not just the mitral valve, but any biomechanical aspect using computational simulation in designing medical devices.

  14. [A case of death due to mitral regurgitation caused by traumatic mitral valve injury].

    PubMed

    Iwasaki, Y; Kojima, T; Yasui, W; Nagasawa, N; Yashiki, M

    1996-06-01

    A 51-year-old male, who had been driving a motor bicycle, was involved in a traffic accident with a trailer, and he died immediately after the accident. According to the external examination of the victim, no fatal injuries were found. The medico-legal autopsy revealed a rupture of the left side of the pericardium, and a tear of the posterior leaflet of the mitral valve. There were no injuries of the papillary muscles and chordae. The cause of death was due to traumatic mitral regurgitation.

  15. Echocardiographic evaluation of mitral stenosis using diastolic posterior left ventricular wall motion.

    PubMed

    Wise, J R

    1980-05-01

    The slope of the posterior left ventricular wall motion in diastole (LVDS) was determined by echocardiography in 25 normal subjects and 21 patients with mitral stenosis. Patients with mitral stenosis had reduced LVDS that was related to the degree of mitral stenosis determined by calculated mitral valve area (r = 0.92). The mitral valve area correlated more closely with the LVDS than with the left atrial emptying index derived from the posterior aortic wall motion. Three patients with mitral stenosis had an increased LVDS after mitral valvotomy or mitral valve replacement. One patient with a stenotic mitral valve prosthesis had reduced LVDS. The results of this study suggest that analysis of the LVDS would be useful in predicting the severity of mitral stenosis and may be beneficial in evaluating patients with suspected prosthetic mitral valve malfunction.

  16. Myxomatous mitral valve disease in dogs: Does size matter?

    PubMed Central

    Parker, Heidi G.; Kilroy-Glynn, Paul

    2012-01-01

    Myxomatous mitral valve disease (MMVD) is the most commonly diagnosed cardiovascular disease in the dog accounting for more than 70% of all cardiovascular disease in dogs. As are most canine diseases with genetic underpinnings, risk of MMVD is greatly increased in a subset of breeds. What is uncommon is that the vast majority of the breeds at elevated risk for MMVD are small or toy breeds with average adult weights under 9 kg. These breeds appear to have little in common other than their diminutive size. In the following review we propose a number of mechanisms by which relatively unrelated small breeds may have developed a predisposition for chronic valvular disorders. Although factors such as age are key in the expression of MMVD, taking a comprehensive look at the commonalities, as well as the differences, between the susceptible breeds may assist in finding the causal variants responsible for MMVD and translating them to improved treatments for both dogs and humans. PMID:22356836

  17. Chemical separation of disc components using RAVE

    NASA Astrophysics Data System (ADS)

    Wojno, Jennifer; Kordopatis, Georges; Steinmetz, Matthias; McMillan, Paul; Matijevič, Gal; Binney, James; Wyse, Rosemary F. G.; Boeche, Corrado; Just, Andreas; Grebel, Eva K.; Siebert, Arnaud; Bienaymé, Olivier; Gibson, Brad K.; Zwitter, Tomaž; Bland-Hawthorn, Joss; Navarro, Julio F.; Parker, Quentin A.; Reid, Warren; Seabroke, George; Watson, Fred

    2016-10-01

    We present evidence from the RAdial Velocity Experiment (RAVE) survey of chemically separated, kinematically distinct disc components in the solar neighbourhood. We apply probabilistic chemical selection criteria to separate our sample into α-low (`thin disc') and α-high (`thick disc') sequences. Using newly derived distances, which will be utilized in the upcoming RAVE DR5, we explore the kinematic trends as a function of metallicity for each of the disc components. For our α-low disc, we find a negative trend in the mean rotational velocity (Vφ) as a function of iron abundance ([Fe/H]). We measure a positive gradient ∂Vφ/∂[Fe/H] for the α-high disc, consistent with results from high-resolution surveys. We also find differences between the α-low and α-high discs in all three components of velocity dispersion. We discuss the implications of an α-low, metal-rich population originating from the inner Galaxy, where the orbits of these stars have been significantly altered by radial mixing mechanisms in order to bring them into the solar neighbourhood. The probabilistic separation we propose can be extended to other data sets for which the accuracy in [α/Fe] is not sufficient to disentangle the chemical disc components a priori. For such data sets which will also have significant overlap with Gaia DR1, we can therefore make full use of the improved parallax and proper motion data as it becomes available to investigate kinematic trends in these chemical disc components.

  18. Modeling and optimization of an elastic arthroplastic disc for a degenerated disc

    NASA Astrophysics Data System (ADS)

    Ghouchani, Azadeh; Ravari, Mohammad; Mahmoudi, Farid

    2011-10-01

    A three-dimensional finite element model (FEM) of the L3-L4 motion segment using ABAQUS v 6.9 has been developed. The model took into account the material nonlinearities and is imposed different loading conditions. In this study, we validated the model by comparison of its predictions with several sets of experimental data. Disc deformation under compression and segmental rotational motions under moment loads for the normal disc model agreed well with the corresponding in vivo studies. By linking ABAQUS with MATLAB 2010.a, we determined the optimal Young s modulus as well as the Poisson's ratio for the artificial disc under different physiologic loading conditions. The results of the present study confirmed that a well-designed elastic arthroplastic disc preferably has an annulus modulus of 19.1 MPa and 1.24 MPa for nucleus section and Poisson ratio of 0.41 and 0.47 respectively. Elastic artificial disc with such properties can then achieve the goal of restoring the disc height and mechanical function of intact disc under different loading conditions and so can reduce low back pain which is mostly caused due to disc degeneration.

  19. Clinical and morphologic observations after simultaneous replacement of the tricuspid, mitral and aortic valves.

    PubMed

    Sullivan, M F; Roberts, W C

    1986-10-01

    Clinical and morphologic observations are described in 12 patients who underwent simultaneous replacement of the tricuspid, mitral and aortic valves. All 12 patients had mitral stenosis, 10 aortic valve stenosis and 2 pure aortic valve regurgitation; 5 had tricuspid valve stenosis and 7 pure tricuspid valve regurgitation. Of the 10 patients who died within 60 days of triple valve replacement, 7 had the low cardiac output syndrome, which in 4, and possibly 5, of the 7 was attributed to prosthetic aortic valve stenosis. In none of the 12 patients was the ascending aorta dilated, and in the 4 (possibly 5) patients with low cardiac output, the space between the surface of the caged poppet (4 patients) or margins of the tilting disc (1 patient) in the aortic valve position and the aortic endothelium appeared inadequate to allow unobstructed flow despite small-sized prostheses in all but 1 patient. Thus, aortic valve replacement in the setting of triple valve dysfunction is hazardous or potentially so. The relative small sizes of the hearts in these patients also make valve replacement more difficult (and hazardous) compared to hearts with larger ventricles and aortas.

  20. Fluid-structure interaction and structural analyses using a comprehensive mitral valve model with 3D chordal structure.

    PubMed

    Toma, Milan; Einstein, Daniel R; Bloodworth, Charles H; Cochran, Richard P; Yoganathan, Ajit P; Kunzelman, Karyn S

    2016-06-25

    Over the years, three-dimensional models of the mitral valve have generally been organized around a simplified anatomy. Leaflets have been typically modeled as membranes, tethered to discrete chordae typically modeled as one-dimensional, non-linear cables. Yet, recent, high-resolution medical images have revealed that there is no clear boundary between the chordae and the leaflets. In fact, the mitral valve has been revealed to be more of a webbed structure whose architecture is continuous with the chordae and their extensions into the leaflets. Such detailed images can serve as the basis of anatomically accurate, subject-specific models, wherein the entire valve is modeled with solid elements that more faithfully represent the chordae, the leaflets, and the transition between the two. These models have the potential to enhance our understanding of mitral valve mechanics and to re-examine the role of the mitral valve chordae, which heretofore have been considered to be 'invisible' to the fluid and to be of secondary importance to the leaflets. However, these new models also require a rethinking of modeling assumptions. In this study, we examine the conventional practice of loading the leaflets only and not the chordae in order to study the structural response of the mitral valve apparatus. Specifically, we demonstrate that fully resolved 3D models of the mitral valve require a fluid-structure interaction analysis to correctly load the valve even in the case of quasi-static mechanics. While a fluid-structure interaction mode is still more computationally expensive than a structural-only model, we also show that advances in GPU computing have made such models tractable. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Functional Mitral Regurgitation: Appraising the Evidence Behind Recommended Treatment Strategies.

    PubMed

    Samad, Zainab; Velazquez, Eric J

    2016-12-01

    Functional mitral regurgitation (MR) is the most common type of MR encountered in clinical practice. Because the disease arises from the ventricular aspect of the mitral valve apparatus, treatment therapies are less defined and outcomes are poor. In this review, the state of evidence for medical and surgical therapy in functional MR is appraised. Future directions for research in this area are also defined.

  2. Myxomatous Mitral Valve with Prolapse and Flail Scallop

    PubMed Central

    Fan, Jerry; Timbrook, Alexa; Said, Sarmad; Babar, Kamran; Teleb, Mohamed; Mukherjee, Debabrata; Abbas, Aamer

    2016-01-01

    Summary Background Myxomatous mitral valve with prolapse are classically seen with abnormal leaflet apposition during contraction of the heart. Hemodynamic disorders can result from eccentric mitral regurgitation usually caused by chordae tendinae rupture or papillary muscle dysfunction. Echocardiography is the gold standard for evaluation of leaflet flail and prolapse due to high sensitivity and specificity. Though most mitral valve prolapse are asymptomatic those that cause severe regurgitation need emergent surgical intervention to prevent disease progression. Case Report We report a 54 year old Hispanic male who presented with progressively worsening dyspnea and palpitations. Initial evaluation was significant for atrial fibrillation on electrocardiogram with subsequent echocardiography revealing myxomatous mitral valve with prolapse. Following surgical repair of the mitral valve, the dyspnea and palpitations resolved. Conclusions Mitral valve prolapse is a common valvular abnormality but the pathogenic cause of myxomatous valves has not been elucidated. Several theories describe multiple superfamilies of proteins to be involved in the process. Proper identification of these severe mitral regurgitation due to these disease valves will help relieve symptomatic mitral valve prolapse patients. PMID:27279924

  3. Single-Suture Neochorda-Folding Plasty for Mitral Regurgitation

    PubMed Central

    Park, Jong Myung; Je, Hyung Gon; Lee, Sang Kwon

    2016-01-01

    The single-suture neochorda-folding plasty technique is a modification of existing mitral valve repair techniques. In the authors’ experience, its simplicity, reliability, and versatility make it a useful technique for mitral valve repair, especially when a minimally invasive approach is used. PMID:26889453

  4. Multiple purpose simulator using a natural porcine mitral valve.

    PubMed

    Arita, Makoto; Tono, Sumihiro; Kasegawa, Hitoshi; Umezu, Mitsuo

    2004-12-01

    An in vitro pulsatile simulator with a porcine mitral valve was developed in order to simulate physiologic and diseased mitral valve conditions. Evaluation of these conditions was conducted from a hydrodynamic and annulus behavior point of view. We found it possible to simulate mild "mitral valve prolapse" and to obtain quantitative data related to the condition. The diseased condition produced a 40% greater regurgitant volume than that observed under the normal condition (p < 0.0001). Regarding the leakage volume, the diseased condition exhibited about 2.6 times more leakage than the normal condition. The mitral valve simulator proposed in this study is considered fairly stable with respect to both hemodynamics and the behavior of the annulus, and it is an adequate simulator for modeling various types of normal and diseased mitral valve conditions.

  5. Comparison of viscoelastic properties of suture versus porcine mitral valve chordae tendineae.

    PubMed

    Cochran, R P; Kunzelman, K S

    1991-12-01

    Recent reports have advocated the use of polytetrafluoroethylene (PTFE) suture for replacement or reinforcement of ruptured or elongated mitral valve chordae tendineae. The mechanical properties of PTFE (Gore-Tex) and other sutures were determined and compared to those of porcine mitral valve chordae. The results were analyzed to assess how closely chordal mechanical function may be simulated by synthetic suture materials. Chordae tendineae and suture samples were tested in uniaxial tension using an INSTRON Model 1000 at strain rates of 5 and 10 mm/min. The stress (g/mm2) was plotted versus strain, and the elastic modulus determined as the slope of the curve. Chordae tendineae exhibited a nonlinear viscoelastic stress/strain behavior. The elastic modulus of both suture types tested was significantly higher than that of the chordae. However, the PTFE suture did exhibit some viscoelastic characteristics (hysteresis and creep) that begin to approach the chordal behavior. Chordal viscoelastic behavior results from the inherent composite structure (collagen, elastin, endothelium, water, and ground substance). As yet, no synthetic materials are able to imitate this behavior with the appropriate tensile strength and fatigue resistant characteristics. At present, PTFE appears to be the best synthetic alternative for chordal replacement, due to its limited viscoelastic capabilities. Nevertheless, the need to more nearly approximate the mechanical behavior of mitral valve chordae tendineae with synthetic material warrants further investigation.

  6. Holographic optical disc

    NASA Astrophysics Data System (ADS)

    Zhou, Gan; An, Xin; Pu, Allen; Psaltis, Demetri; Mok, Fai H.

    1999-11-01

    The holographic disc is a high capacity, disk-based data storage device that can provide the performance for next generation mass data storage needs. With a projected capacity approaching 1 terabit on a single 12 cm platter, the holographic disc has the potential to become a highly efficient storage hardware for data warehousing applications. The high readout rate of holographic disc makes it especially suitable for generating multiple, high bandwidth data streams such as required for network server computers. Multimedia applications such as interactive video and HDTV can also potentially benefit from the high capacity and fast data access of holographic memory.

  7. [Ventricular and myocardial function in mitral regurgitation (author's transl)].

    PubMed

    Dübbers, H W; Neuhaus, K L; Spiller, P; Tebbe, U

    1979-07-01

    Left ventricular and myocardial performance were analyzed in 9 patients with chronic volume overload by mitral regurgitation from biplane cineventriculograms, simultaneous pressure recordings and cardiac output (thermodilution method) determinations. In spite of a considerable regurgitant fraction (49 +/- 17% of total stroke volume) cardiac index on the average is normal (CI = 3.3 +/- 0.7 l . min-1). The main compensatory mechanism to maintain cardiac ouput in hypertorphy (WED = 1.1 +/- 0.2 cm; LVMI = 216 +/- 62 g . m-2; LVMI/EDVI = 1.3 +/- 0.3 g . ml-1) and dilatation (EDVI = 163 +/- 37 ml . m-2). An increase of preload is of minor importance (PLVED = 15 +/- 7 mmHg; sigma ED = (40 +/- 19) x 10(3) dyn . cm-2). Left ventricular enlargement and wall mass are related to the degree of clinical heart failure (NYHA). Enddiastolic volume on the average is more increased than total stroke volume (89 +/- 31 ml . m-2). Ejection fraction (EF = 54 +/- 7%) was depressed despite a normal afterload (sigma tej = (171 +/- 37 x 10(3) dyn. cm-2; sigma max = (247 +/- 48 x 10(3) dyn . cm-2). The reduced ejection fraction and diminished myocardial power are related to an impairment of myocardial function (VMW . sigma tej = (83 +/- 39) x 10(3) dyn . cm-2 . s-1; VMW . sigma tej/ln sigma ED = 7.9 +/- 3.6 x 10(3) dyn . cm-2 . s-1). In comparable degrees of heart failure myocardial function is more compromised in patients with mitral than with aortic regurgitation.

  8. Porcine mitral valve interstitial cells in culture.

    PubMed

    Lester, W; Rosenthal, A; Granton, B; Gotlieb, A I

    1988-11-01

    There are connective tissue cells present within the interstitium of the heart valves. This study was designed to isolate and characterize mitral valve interstitial cells from the anterior leaflet of the mitral valve. Explants obtained from the distal part of the leaflet, having been scraped free of surface endocardial cells, were incubated in medium 199 supplemented with 10% fetal bovine serum. Cells grew out of the explant after 3 to 5 days and by 3 weeks these cells were harvested and passaged. Passages 1 to 22 were characterized in several explant sets. The cells showed a growth pattern reminiscent of fibroblasts. Growth was dependent on serum concentration. Cytoskeletal localization of actin and myosin showed prominent stress fibers. Ultrastructural studies showed many elongated cells with prominent stress fibers and some gap junctions and few adherens junctions. There were as well cells with fewer stress fibers containing prominent Golgi complex and dilated endoplasmic reticulum. In the multilayered superconfluent cultures, the former cells tended to be on the substratum of the dish or surface of the multilayered culture, whereas the latter was generally located within the layer of cells. Extracellular matrix was prominent in superconfluent cultures, often within the layers as well. Labeling of the cells with antibody HHF 35 (Tsukada T, Tippens D, Gordon D, Ross R, Gown AM: Am J Pathol 126:51, 1987), which recognizes smooth muscle cell actin, showed prominent staining of the elongated stress fiber-containing cells and much less in the secretory type cells. These studies show that interstitial mitral valve cells can be grown in culture and that either two different cell types or one cell type with two phenotypic expressions is present in culture.

  9. Libman-Sacks Endocarditis with Unusual Large Size Vegetation Involving the Mitral Valve.

    PubMed

    Bani Hani, Amjad; Abu-Abeeleh, Mahmoud; Al Kharabsheh, Murad M; Qabba'ah, Lubaba

    2016-12-21

    Antiphospholipid syndrome (APS) is an autoimmune hypercoagulable disorder characterized by thrombophilia, vascular thrombosis, and recurrent abortions associated with persistent antiphospholipid antibodies. APS may exist in its primary form, or more commonly is found to be associated with variety of rheumatic disorders, such as systemic lupus erythematosus. Cardiac involvement is not an uncommon complication in primary antiphospholipid patients. Libman-Sacks lesions are typically small, sessile, and wart-like, varying in size from 1-4 mm. Here we present an unusual case of a 37 year-old pregnant woman who suffered from heart failure associated with primary antiphospholipid syndrome and Libman-Sacks endocarditis, with large vegetations involving the mitral valve. The patient underwent mitral valve replacement with a mechanical prosthesis.

  10. Finite element modeling of mitral leaflet tissue using a layered shell approximation

    PubMed Central

    Ratcliffe, Mark B.; Guccione, Julius M.

    2012-01-01

    The current study presents a finite element model of mitral leaflet tissue, which incorporates the anisotropic material response and approximates the layered structure. First, continuum mechanics and the theory of layered composites are used to develop an analytical representation of membrane stress in the leaflet material. This is done with an existing anisotropic constitutive law from literature. Then, the concept is implemented in a finite element (FE) model by overlapping and merging two layers of transversely isotropic membrane elements in LS-DYNA, which homogenizes the response. The FE model is then used to simulate various biaxial extension tests and out-of-plane pressure loading. Both the analytical and FE model show good agreement with experimental biaxial extension data, and show good mutual agreement. This confirms that the layered composite approximation presented in the current study is able to capture the exponential stiffening seen in both the circumferential and radial directions of mitral leaflets. PMID:22971896

  11. Simulation Based Design and Evaluation of a Transcatheter Mitral Heart Valve Frame

    PubMed Central

    Young, Melissa; Erdemir, Ahmet; Stucke, Samantha; Klatte, Ryan; Davis, Brian; Navia, Jose L.

    2013-01-01

    In certain populations, open heart surgery to replace a diseased mitral valve is not an option, leaving percutaneous delivery a viable alternative. However, a surgical transcatheter based delivery of a metallic support frame incorporating a tissue derived valve puts considerable constraints on device specifications. Expansion to a large diameter from the catheter diameter without mechanical fracture involves advanced device design and appropriate material processing and selection. In this study, a new frame concept is presented with a desirable feature that incorporates wings that protrude during expansion to establish adequate fixation. Expansion characteristics of the design in relation to annulus fixation were quantified through finite element analysis predictions of the frame wing span and angles. Computational modeling and simulation was used to identify many favorable design features for the transcatheter mitral valve frame and obtain desired expansion diameters (35–45mm), acceptable radial stiffness (2.7N/mm), and ensure limited risk of failure based on predicted plastic deformations. PMID:23372624

  12. [Surgical techniques in mitral valve diseases. Reconstruction and/or replacement].

    PubMed

    Noack, T; Mohr, F-W

    2016-02-01

    Mitral valve (MV) disease is one of the most common heart valve diseases. The surgical and interventional treatment for MV disease requires a multidisciplinary approach. For primary mitral valve regurgitation (MVR) surgical MV repair is the treatment of choice, which can be performed with an excellent outcome and long-term survival in reference centers. The surgical technique used for MV repair depends on the pathological mechanism, the morphological dimensions of the MV, the operative risk and the expertise of the cardiac surgeon. The surgical and interventional treatment of secondary MVVR is the subject of on-going discussions. In patients with moderate secondary MVR undergoing coronary artery bypass grafting, concomitant MV repair should be performed. In the presence of severe secondary MR with risk factors for failure of MV repair, patients should consider having MV replacement. In the rare cases of patients presenting with mitral valve stenosis (MVS) MV repair can be considered in young patients and who are most often treated with MV replacement. The choice between biological or mechanical MV replacement depends on the pathophysiology, the comorbidities, the amount of anticoagulation necessary and the age of the patient. New percutaneous techniques for MV replacement offer new treatment options for reoperation in high-risk patients.

  13. Is minimally invasive thoracoscopic surgery the new benchmark for treating mitral valve disease?

    PubMed Central

    Goldstone, Andrew B.

    2016-01-01

    The treatment of mitral valve disease remains dynamic; surgeons and patients must now choose between many different surgical options when addressing mitral regurgitation and mitral stenosis. Notably, advances in imaging and surgical instrumentation allow surgeons to perform less invasive mitral valve surgery that spares the sternum. With favorable long-term data now emerging, we compare the benefits and risks of thoracoscopic mitral valve surgery with that through conventional sternotomy or surgery that is robot-assisted. PMID:27942489

  14. Bryan total disc arthroplasty: a replacement disc for cervical disc disease

    PubMed Central

    Wenger, Markus; Markwalder, Thomas-Marc

    2010-01-01

    Total disc arthroplasty is a new option in the treatment of cervical degenerative disc disease. Several types of cervical disc prostheses currently challenge the gold-standard discectomy and fusion procedures. This review describes the Bryan Cervical Disc System and presents the Bryan prosthesis, its indications, surgical technique, complications, and outcomes, as given in the literature. PMID:22915917

  15. [Biology and mechanobiology of the intervertebral disc].

    PubMed

    González Martínez, Emilio; García-Cosamalón, José; Cosamalón-Gan, Iván; Esteban Blanco, Marta; García-Suarez, Olivia; Vega, José A

    2017-01-24

    The intervertebral disc (IVD) is noted for its low cell content, and being the largest avascular structure of human body. The low amount of cells in the disc have to adapt to an anaerobic metabolism with low oxygen pressure and acidic pH. Apart from surviving in an adverse microenvironment, they are exposed to a high level of mechanical stress. The biological adaptation of cells to acidosis and hyperosmolarity conditions are regulated by mechanoproteins, which are responsible for converting a mechanical signal into a cellular response, thus modifying its gene expression. Mechanobiology helps us to better understand the pathophysiology of IVD and its potential biological repair.

  16. Repeat mitral valve replacement: 30-years' experience.

    PubMed

    Expósito, Víctor; García-Camarero, Tamara; Bernal, José M; Arnáiz, Elena; Sarralde, Aurelio; García, Iván; Berrazueta, José R; Revuelta, José M

    2009-08-01

    Prosthetic heart valve dysfunction is an acquired condition that carries a significant risk of emergency surgery. However, the long-term natural history of the condition is not well understood. Between 1974 and 2006, 1535 isolated mitral valve replacements were performed at our hospital (in-hospital mortality 5%). In total, 369 patients needed a second operation (in-hospital mortality 8.1%), while 80 (age 59.8+/-11.4 years) needed a third. The reasons for the third intervention were structural deterioration (67.5%), paravalvular leak (20%) and endocarditis (6.3%). Some 15 patients died in hospital (18.8%). After a mean follow-up period of 17.8 years, 21 patients needed another intervention (i.e., a fourth intervention). The actuarial reoperation-free rate at 20 years was 40.1+/-13.8%. The late mortality rate was 58.5% (18-year survival rate 15.4+/-5.4%). Indications for repeat mitral valve replacement must be judged on an individual basis given the high risk associated with surgery.

  17. Disc in Flames: Roles of TNF-α and IL-1β in Intervertebral Disc Degeneration

    PubMed Central

    Johnson, Zariel I.; Schoepflin, Zachary R.; Choi, Hyowon; Shapiro, Irving M.; Risbud, Makarand V.

    2016-01-01

    The intervertebral disc is an important mechanical structure that allows range of motion of the spinal column. Degeneration of the intervertebral disc, incited by aging, traumatic insult, genetic predisposition, or other factors, is often defined by functional and structural changes in the tissue, including excessive breakdown of the extracellular matrix, increased disc cell senescence and death, and compromised biomechanical function of the tissue. Intervertebral disc degeneration is strongly correlated with low back pain, which is a highly prevalent and costly condition, significantly contributing to loss in productivity and health care costs. Disc degeneration is a chronic, progressive condition, and current therapies are limited and often focused on symptomatic pain relief rather than curtailing the progression of the disease. Inflammatory processes, exacerbated by cytokines TNF-α and IL-1β are believed to be key mediators of disc degeneration and low back pain. In this review, we describe the contributions of TNF-α and IL-1β to changes seen during disc degeneration at the cellular and tissue level, new evidence suggesting a link between infection of the spine and low back pain, and the emerging therapeutic modalities aimed at combating these processes. PMID:26388614

  18. Mitral Valve Surgery: Current Minimally Invasive and Transcatheter Options

    PubMed Central

    Ramlawi, Basel; Gammie, James S.

    2016-01-01

    The mitral valve is a highly complex structure, the competency and function of which relies on the harmonious action of its component parts. Minimally invasive cardiac surgery (MICS) for mitral valve repair or replacement (MVR/r) has been performed successfully with incremental improvements in techniques over the past decade. These minimally invasive procedures, while attractive to patients and referring physicians, should meet the same high bar for optimal clinical outcomes and long-term durability of valve repair as traditional sternotomy procedures. The majority of MICS MVR/r procedures are performed via a right minithoracotomy approach with direct or camera-assisted visualization, with a minority of centers performing robotic MVR/r. Outcomes with MICS MVR/r have been shown to have similar morbidity and mortality rates as traditional sternotomy MV procedures but with the advantage of reduced transfusions, postoperative atrial fibrillation, and time to recovery. More recently, transcatheter mitral valve repair and replacement (TMVR/r) has become a reality. Percutaneous MV repair technology is currently FDA approved for patients with nonsurgical high-risk degenerative mitral regurgitation. Other TMVR/r technology is at various levels of preclinical and clinical investigation, although these devices are proving to be more challenging compared to transcatheter aortic valve replacement (TAVR) due to the significantly more complex mitral anatomy and the greater heterogeneity of mitral disease requiring treatment. In this article, we review current techniques for MICS MVR/r and upcoming catheter-based therapies for the mitral valve. PMID:27127558

  19. Mitral Valve Surgery: Current Minimally Invasive and Transcatheter Options.

    PubMed

    Ramlawi, Basel; Gammie, James S

    2016-01-01

    The mitral valve is a highly complex structure, the competency and function of which relies on the harmonious action of its component parts. Minimally invasive cardiac surgery (MICS) for mitral valve repair or replacement (MVR/r) has been performed successfully with incremental improvements in techniques over the past decade. These minimally invasive procedures, while attractive to patients and referring physicians, should meet the same high bar for optimal clinical outcomes and long-term durability of valve repair as traditional sternotomy procedures. The majority of MICS MVR/r procedures are performed via a right minithoracotomy approach with direct or camera-assisted visualization, with a minority of centers performing robotic MVR/r. Outcomes with MICS MVR/r have been shown to have similar morbidity and mortality rates as traditional sternotomy MV procedures but with the advantage of reduced transfusions, postoperative atrial fibrillation, and time to recovery. More recently, transcatheter mitral valve repair and replacement (TMVR/r) has become a reality. Percutaneous MV repair technology is currently FDA approved for patients with nonsurgical high-risk degenerative mitral regurgitation. Other TMVR/r technology is at various levels of preclinical and clinical investigation, although these devices are proving to be more challenging compared to transcatheter aortic valve replacement (TAVR) due to the significantly more complex mitral anatomy and the greater heterogeneity of mitral disease requiring treatment. In this article, we review current techniques for MICS MVR/r and upcoming catheter-based therapies for the mitral valve.

  20. Echocardiographic analysis of a malfunctioning Davila-Sierra mitral valve.

    PubMed

    Tri, Terry B.; Gregoratos, Gabriel

    1981-03-01

    Although the Davila-Sierra mitral valve prosthesis was removed from the market nearly a decade ago, a number of patients still have this valve in place. We recently studied the echocardiographic features of a malfunctioning Davila-Sierra mitral valve prosthesis. Abnormalities that suggested improper functioning of the prosthesis included a markedly delayed poppet opening and an early diastolic hump believed to represent motion of the mitral annulus. Previously described echocardiographic indications of dys-function were not observed in our patient. We report the first known echocardiographic evaluation of a Davila-Sierra prosthesis.

  1. Echocardiographic analysis of a malfunctioning Davila-Sierra mitral valve

    PubMed Central

    Tri, Terry B.; Gregoratos, Gabriel

    1981-01-01

    Although the Davila-Sierra mitral valve prosthesis was removed from the market nearly a decade ago, a number of patients still have this valve in place. We recently studied the echocardiographic features of a malfunctioning Davila-Sierra mitral valve prosthesis. Abnormalities that suggested improper functioning of the prosthesis included a markedly delayed poppet opening and an early diastolic hump believed to represent motion of the mitral annulus. Previously described echocardiographic indications of dys-function were not observed in our patient. We report the first known echocardiographic evaluation of a Davila-Sierra prosthesis. Images PMID:15216230

  2. [A Case of Mitral Valvular Re-repair in a Patient with Hemolytic Anemia after Mitral Valvular Repair].

    PubMed

    Tomino, Mikiko; Miyata, Kazuto; Takeshita, Yuji; Kaneko, Koki; Kanazawa, Hiroko; Uchino, Hiroyuki

    2015-07-01

    A 54-year-old woman was admitted for mitral valvular repair. After folding plasty to A3, a 30 mm Cosgrove-Edwards ring was placed. There was no mitral regurgitation jet observed by transesophageal echocardiography (TEE) during the operation. However, high blood pressure was monitored and treated in the intensive care unit, hemolytic anemia developed, and the serum lactate dehydrogenase level was elevated. Two weeks after the operation, serum lactate dehydrogenase was again elevated. TEE showed mild mitral regurgitation and the regurgitation jet colliding with the annuloplasty ring. Multiple transfusions of red blood cells were required. Repeat surgery was therefore undertaken. Lam and associates previously studying patients on hemolysis after mitral valvular repair noted high grade mitral regurgitation jets fragmented or accelerated. In the present case, mitral regurgitation was mild, but the high velocity and manner of regurgitation (collision with the annuloplasty ring) could cause hemolytic anemia. In the present case, high blood pressure might have caused chordae rupture. Furthermore, a flexible ring, such as the Cosgrove-Edwards ring, is likely to cause hemolytic anemia. As contributing factors to hemolysis after mitral valvular repair, perioperative blood pressure management and type of ring are significant.

  3. Resolution of massive left atrial appendage thrombi with rivaroxaban before balloon mitral commissurotomy in severe mitral stenosis

    PubMed Central

    Li, Yuechun; Lin, Jiafeng; Peng, Chen

    2016-01-01

    Abstract Rationale: Data on nonvitamin K antagonist oral anticoagulant being used for the treatment of LAA thrombi are limited only in nonvalvular atrial fibrillation. There are no data on the antithrombotic efficacy and safety of nonvitamin K antagonist oral anticoagulant in the resolution of left atrial appendage (LAA) thrombi in patients with rheumatic mitral stenosis. Patient concerns: A 49-year-old woman with known rheumatic mitral stenosis and atrial fibrillation was referred for percutaneous transvenous mitral commissurotomy because of progressive dyspnea on exertion over a period of 3 months. Diagnoses: Transesophageal echocardiography (TEE) demonstrated a large LAA thrombus protruding into left atria cavity before the procedure. Interventions: Direct factor Xa (FXa) inhibitor rivaroxaban (20 mg/d) was started for the patient. After 3 weeks of rivaroxaban treatment TEE showed a relevantly decreased thrombus size, and a complete thrombus resolution was achieved after 5 weeks of anticoagulant therapy with the FXa inhibitor. Outcomes: To the best of our knowledge, this is the first documented case of large LAA thrombus resolution with nonvitamin K antagonist oral anticoagulant in severe mitral stenosis, and in which percutaneous transvenous mitral commissurotomy was performed subsequently. Lessons: The report indicated that rivaroxaban could be a therapeutic option for mitral stenosis patients with LAA thrombus. Further study is required before the routine use of rivaroxaban in patients with rheumatic mitral stenosis and atrial fibrillation. PMID:27930571

  4. Study of Effectiveness and Safety of Percutaneous Balloon Mitral Valvulotomy for Treatment of Pregnant Patients with Severe Mitral Stenosis

    PubMed Central

    Joshi, Hasit Sureshbhai; Deshmukh, Jagjeet Kishanrao; Prajapati, Jayesh Somabhai; Sahoo, Sibasis Shahsikant; Vyas, Pooja Maheshbhai

    2015-01-01

    Introduction In pregnant women mitral stenosis is the commonest cardiac valvular lesion. When it is present in majorly severe condition it leads to maternal and fetal morbidity and mortality. In mitral stenosis pregnancy can lead to development of heart failure. Aim To evaluate the safety and efficacy of balloon mitral valvulotomy (BMV) in pregnant females with severe mitral stenosis. Materials and Methods A total of 30 pregnant patients who underwent BMV were included in the study from July 2011 to November 2013. Clinical follow-up during pregnancy was done every 3 months until delivery and after delivery. The mean follow up time after BMV was 6.72±0.56 months. Results From the 30 pregnant females 14 (46.67%) and 16 (53.3%) patients underwent BMV during the third and second trimester of pregnancy respectively. The mean mitral valve area was 0.85+0.16 cm2 before BMV that increased to 1.60+0.27 cm2 (p<0.0001) immediately after BMV. Peak and mean diastolic gradients had decreased significantly within 48 hours after the procedure (p<0.001) but remained very much unchanged at 6.72 month period of follow-up. Two patients had an increase in mitral regurgitation by 2 grades. Conclusion During pregnancy BMV technique is safe and effective in patients with severe mitral stenosis. This results in marked symptomatic relief along with long term maternal and fetal outcomes. PMID:26816932

  5. Percutaneous mitral valve repair with MitraClip for severe functional mitral regurgitation.

    PubMed

    Yeo, Khung Keong; Ding, Zee Pin; Chua, Yeow Leng; Lim, Soo Teik; Sin, Kenny Yoong Kong; Tan, Jack Wei Chieh; Chiam, Paul Toon Lim; Hwang, Nian Chih; Koh, Tian Hai

    2013-01-01

    A 67-year-old Chinese woman with comorbidities of chronic obstructive lung disease, hypertension and prior coronary artery bypass surgery presented with severe functional mitral regurgitation (MR) and severely depressed left ventricular function. She was in New York Heart Association (NYHA) Class II-III. Due to high surgical risk, she was referred for percutaneous treatment with the MitraClip valve repair system. This procedure is typically performed via the femoral venous system and involves a transseptal puncture. A clip is delivered to grasp the regurgitant mitral valve leaflets and reduce MR. This was performed uneventfully in our patient, with reduction of MR from 4+ to 1+. She was discharged on post-procedure Day 2 and her NYHA class improved to Class I. This was the first successful MitraClip procedure performed in Asia and represents a valuable treatment option in patients with severe MR, especially those with functional MR or those at high surgical risk.

  6. Progression to moderate or severe mitral regurgitation after percutaneous transvenous mitral commissurotomy using stepwise inflation technique.

    PubMed

    Matsubara, T; Yamazoe, M; Tamura, Y; Tanabe, Y; Hori, T; Konno, T; Higuchi, K; Ida, T; Takemoto, M; Aizawa, Y

    1998-05-01

    Progression to moderate or severe mitral regurgitation (MR) was studied after Inoue balloon percutaneous transvenous mitral commissurotomy (PTMC) using the stepwise inflation technique, performed at increments of 1 mm of balloon diameter, in 49 consecutive patients with rheumatic mitral stenosis (aged from 32-73 years; 8 males, 41 females). The patients were classified on the basis of the degree of MR after PTMC, compared with that before PTMC, into either Group A, development of moderate or more severe (> or = grade 2) MR (n = 8) or Group B, no increase in MR or development of mild (grade 1) MR (n = 41). Progression to moderate or severe MR was significantly associated only with advanced age (60 +/- 8 vs 52 +/- 10 years, p < 0.05) and narrower mitral valve area (0.87 +/- 0.35 vs 1.11 +/- 0.29 cm2, p < 0.05), but other characteristics before PTMC were similar in both groups. There was no difference between the two groups in the total number and degree of balloon inflation. Immediately before the final inflation, the left atrial mean pressure and v wave pressure were decreased in smaller degrees in Group A compared with Group B (-2 +/- 2 vs -5 +/- 4 mmHg, p < 0.05; -2 +/- 2 vs -6 +/- 6 mmHg, p < 0.05, respectively). Thus, the stepwise inflations require careful monitoring of changes in the left atrial pressure and waveform to recognize the aggravation of MR, especially in older patients with severe stenosis. Patients who do not have a significant drop in left atrial mean pressure and v wave pressure during stepwise inflations of the balloon might be at risk of development of moderate or severe MR after further dilations.

  7. Fully automated software for mitral annulus evaluation in chronic mitral regurgitation by 3-dimensional transesophageal echocardiography

    PubMed Central

    Aquila, Iolanda; Fernández-Golfín, Covadonga; Rincon, Luis Miguel; González, Ariana; García Martín, Ana; Hinojar, Rocio; Jimenez Nacher, Jose Julio; Indolfi, Ciro; Zamorano, Jose Luis

    2016-01-01

    Abstract Three-dimensional (3D) transesophageal echocardiography (TEE) is the gold standard for mitral valve (MV) anatomic and functional evaluation. Currently, dedicated MV analysis software has limitations for its use in clinical practice. Thus, we tested here a complete and reproducible evaluation of a new fully automatic software to characterize MV anatomy in different forms of mitral regurgitation (MR) by 3D TEE. Sixty patients were included: 45 with more than moderate MR (28 organic MR [OMR] and 17 functional MR [FMR]) and 15 controls. All patients underwent TEE. 3D MV images obtained using 3D zoom were imported into the new software for automatic analysis. Different MV parameters were obtained and compared. Anatomic and dynamic differences between FMR and OMR were detected. A significant increase in systolic (859.75 vs 801.83 vs 607.78 mm2; P = 0.002) and diastolic (1040.60 vs. 1217.83 and 859.74 mm2; P < 0.001) annular sizes was observed in both OMR and FMR compared to that in controls. FMR had a reduced mitral annular contraction compared to degenerative cases of OMR and to controls (17.14% vs 32.78% and 29.89%; P = 0.007). Good reproducibility was demonstrated along with a short analysis time (mean 4.30 minutes). Annular characteristics and dynamics are abnormal in both FMR and OMR. Full 3D software analysis automatically calculates several significant parameters that provide a correct and complete assessment of anatomy and dynamic mitral annulus geometry and displacement in the 3D space. This analysis allows a better characterization of MR pathophysiology and could be useful in designing new devices for MR repair or replacement. PMID:27930514

  8. Collagen organization in canine myxomatous mitral valve disease: an x-ray diffraction study.

    PubMed

    Hadian, Mojtaba; Corcoran, Brendan M; Han, Richard I; Grossmann, J Günter; Bradshaw, Jeremy P

    2007-10-01

    Collagen fibrils, a major component of mitral valve leaflets, play an important role in defining shape and providing mechanical strength and flexibility. Histopathological studies show that collagen fibrils undergo dramatic changes in the course of myxomatous mitral valve disease in both dogs and humans. However, little is known about the detailed organization of collagen in this disease. This study was designed to analyze and compare collagen fibril organization in healthy and lesional areas of myxomatous mitral valves of dogs, using synchrotron small-angle x-ray diffraction. The orientation, density, and alignment of collagen fibrils were mapped across six different valves. The findings reveal a preferred collagen alignment in the main body of the leaflets between two commissures. Qualitative and quantitative analysis of the data showed significant differences between affected and lesion-free areas in terms of collagen content, fibril alignment, and total tissue volume. Regression analysis of the amount of collagen compared to the total tissue content at each point revealed a significant relationship between these two parameters in lesion-free but not in affected areas. This is the first time this technique has been used to map collagen fibrils in cardiac tissue; the findings have important applications to human cardiology.

  9. Pregnancy-induced remodeling of collagen architecture and content in the mitral valve.

    PubMed

    Pierlot, Caitlin M; Lee, J Michael; Amini, Rouzbeh; Sacks, Michael S; Wells, Sarah M

    2014-10-01

    Pregnancy produces rapid, non-pathological volume-overload in the maternal circulation due to the demands of the growing fetus. Using a bovine model for human pregnancy, previous work in our laboratory has shown remarkable pregnancy-induced changes in leaflet size and mechanics of the mitral valve. The present study sought to relate these changes to structural alterations in the collagenous leaflet matrix. Anterior mitral valve leaflets were harvested from non-pregnant heifers and pregnant cows (pregnancy stage estimated by fetal length). We measured changes in the thickness of the leaflet and its anatomic layers via Verhoeff-Van Gieson staining, and in collagen crimp (wavelength and percent collagen crimped) via picrosirius red staining and polarized microscopy. Collagen concentration was determined biochemically: hydroxyproline assay for total collagen and pepsin-acid extraction for uncrosslinked collagen. Small-angle light scattering (SALS) assessed changes in internal fiber architecture (characterized by degree of fiber alignment and preferred fiber direction). Pregnancy produced significant changes to collagen structure in the mitral valve. Fiber alignment decreased 17% with an 11.5° rotation of fiber orientation toward the radial axis. Collagen fiber crimp was dramatically lost, accompanied by a 53% thickening of the fibrosa, and a 16% increase in total collagen concentration, both suggesting that new collagen is being synthesized. Extractable collagen concentration was low, both in the non-pregnant and pregnant state, suggesting early crosslinking of newly-synthesized collagen. This study has shown that the mitral valve is strongly adaptive during pregnancy, with significant changes in size, collagen content and architecture in response to rapidly changing demands.

  10. Sinus Rhythm in Rheumatic Mitral Stenosis after Balloon Mitral Valvotomy: Is it Feasible?

    PubMed Central

    Shukla, Anand N; Shah, Saurin; Nayak, Vidya; Prabhu, Sridevi; Pai, Umesh

    2017-01-01

    Introduction Atrial Fibrillation (AF) is largely present in patients with rheumatic valvular disease, leading to hospitalizations. Aim We aimed to study the restoration and maintenance of Sinus Rhythm (SR) in rheumatic patients with Mitral Stenosis (MS) and AF after Balloon Mitral Valvotomy (BMV) and evaluated the factors which affect the maintenance of SR. Materials and Methods A total of 50 patients who underwent BMV at U. N. Mehta Institute of Cardiology and Research Centre from 2010 November to 2013 January were included in the study. Subsequently, all patients were treated with amiodarone and electrical cardioversion was applied in patients in whom it was necessary. The patients were followed for six months for conversion and maintenance of SR. Results Total 34 (68%) patients reverted to SR. Twelve patients reverted to SR with amiodarone and 22 patients with electrical cardioversion and amiodarone. Out of the total, 29 patients and 26 patients remained in SR at the end of follow up at 3 months and 6 months respectively. Conclusion Smaller Left Atrial (LA) size and greater Mitral Valve Area (MVA) are the chief predictors of restoration and maintenance of SR. Combining BMV with an aggressive anti-arrhythmic strategy offers the best prospect of rhythm control. PMID:28384905

  11. Structures induced by companions in galactic discs

    NASA Astrophysics Data System (ADS)

    Kyziropoulos, P. E.; Efthymiopoulos, C.; Gravvanis, G. A.; Patsis, P. A.

    2016-12-01

    Using N-body simulations, we study the structures induced on a galactic disc by repeated flybys of a companion in decaying eccentric orbit around the disc. Our system is composed of a stellar disc, bulge and live dark matter halo, and we study the system's dynamical response to a sequence of a companion's flybys, when we vary (i) the disc's temperature (parametrized by Toomre's Q-parameter) and (ii) the companion's mass and initial orbit. We use a new 3D Cartesian grid code: MAIN (Mesh-adaptive Approximate Inverse N-body solver). The main features of MAIN are reviewed, with emphasis on the use of a new Symmetric Factored Approximate Sparse Inverse matrix in conjunction with the multigrid method that allows the efficient solution of Poisson's equation in three space variables. We find that (i) companions need to be assigned initial masses in a rather narrow window of values in order to produce significant and more long-standing non-axisymmetric structures (bars and spirals) in the main galaxy's disc by the repeated flyby mechanism. (ii) A crucial phenomenon is the antagonism between companion-excited and self-excited modes on the disc. Values of Q > 1.5 are needed in order to allow for the growth of the companion-excited modes to prevail over the growth of the disc's self-excited modes. (iii) We give evidence that the companion-induced spiral structure is best represented by a density wave with pattern speed nearly constant in a region extending from the inner Lindblad resonance to a radius close to, but inside, corotation.

  12. MitraClip catheter-based mitral valve repair system.

    PubMed

    Jönsson, Anders; Settergren, Magnus

    2010-07-01

    The ongoing evolution of transcatheter valve technology is impressive. Mitral valve regurgitation is the most common type of heart valve insufficiency and mitral valve surgery is, next to aortic valve surgery, the second leading valvular surgical procedure in the western world. However, there is a large patient population suffering from mitral valve regurgitation that is currently not treated with heart surgery because of significant morbidity and mortality risks. This large underserved patient population could benefit from a less invasive treatment. The MitraClip system (Abbott Vascular, Menlo Park, CA, USA) is the first commercially available medical technology providing a catheter-based nonsurgical repair alternative for patients suffering from mitral valve regurgitation and has the greatest clinical experience compared with other alternative devices. The device is currently in late-stage clinical trials in the USA and has received the CE mark.

  13. Robotic mitral valve surgery: current limitations and future directions

    PubMed Central

    Suri, Rakesh; Mick, Stephanie; Mihaljevic, Tomislav

    2016-01-01

    Use of the surgical robot facilitates less invasive mitral valve surgery. Although multiple single center studies confirmed excellent results with robotically-assisted mitral valve surgery, both real and perceived limitations have slowed adoption of this technology. Some still question the safety and efficacy of robotically-assisted mitral valve surgery. However, present data suggests that robotic operations can be performed by specialized surgeons in appropriately selected patients without compromising results. That said, the robot does introduce additional procedural complexity related to management of cardiopulmonary bypass and myocardial protection. A direct approach to these challenges combined with careful patient selection enables the surgeon to obtain excellent results with robotically-assisted mitral valve surgery. PMID:27942490

  14. Minimally Invasive, Nonsurgical Approach to Repairing Mitral Valve Leaks

    MedlinePlus

    Minimally Invasive, Nonsurgical Approach to Repairing Mitral Valve Leaks - David X. Zhao, MD Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2017 BroadcastMed, Inc. All rights ...

  15. Anomalous left coronary artery from pulmonary artery with mitral stenosis.

    PubMed

    Das, Mrinalendu; Mahindrakar, Pallavi; Das, Debasis; Behera, Sukanta Kumar; Chowdhury, Saibal Roy; Bandyopadhyay, Biswajit

    2011-08-01

    The usual presentation of anomalous left coronary artery from pulmonary artery is severe left-sided heart failure and mitral valve insufficiency presenting during the first months of life. The manifestations of left heart failure may be masked if pulmonary artery pressure remains high. We believe this is a rarest of rare case of anomalous left coronary artery from pulmonary artery with severe mitral stenosis and pulmonary hypertension in which pulmonary hypertension, along with good collateral circulation helped to preserve left ventricular function.

  16. Severe rheumatic mitral stenosis: a 21st century medusa.

    PubMed

    Carrilho-Ferreira, Pedro; Pedro, Monica Mendes; Varela, Manuel Gato; Diogo, Antonio Nunes

    2011-09-12

    Although the prevalence of rheumatic fever has greatly decreased in developed countries, rheumatic mitral stenosis still causes significant morbidity and mortality. Symptomatic patients have a poor prognosis, with a 0 to 15% 10-year survival rate, particularly if percutaneous or surgical intervention are contraindicated or considered high risk. We present a case of severe rheumatic mitral stenosis with an evolution over 4 decades, in which exceptional venous distention has established.

  17. Reexamining contraindications for minimally invasive mitral valve surgery.

    PubMed

    Reade, Clifton C; Bower, Curtis E; Kypson, Alan P; Nifong, L Wiley; Wooden, William A; Chitwood, W Randolph

    2005-01-01

    Historically, contraindications to minimally invasive or robotic mitral valve surgery have included prior mastectomy, thoracic reconstruction, or chest radiation. However, we believe that by granting flexibility in the choice of skin incision site while performing careful dissection, surgeons can provide these patients the outstanding results afforded by a minithoracotomy. We present a patient who had undergone a prior mastectomy and radiation treatment in whom we performed a minimally invasive mitral valve repair through a right-sided minithoracotomy using the previous mastectomy incision.

  18. The Galactic stellar disc

    NASA Astrophysics Data System (ADS)

    Feltzing, S.; Bensby, T.

    2008-12-01

    The study of the Milky Way stellar discs in the context of galaxy formation is discussed. In particular, we explore the properties of the Milky Way disc using a new sample of about 550 dwarf stars for which we have recently obtained elemental abundances and ages based on high-resolution spectroscopy. For all the stars we also have full kinematic information as well as information about their stellar orbits. We confirm results from previous studies that the thin and the thick discs have distinct abundance patterns. But we also explore a larger range of orbital parameters than what has been possible in our previous studies. Several new results are presented. We find that stars that reach high above the Galactic plane and have eccentric orbits show remarkably tight abundance trends. This implies that these stars formed out of well-mixed gas that had been homogenized over large volumes. We find some evidence that suggest that the event that most likely caused the heating of this stellar population happened a few billion years ago. Through a simple, kinematic exploration of stars with super-solar [Fe/H], we show that the solar neighbourhood contains metal-rich, high velocity stars that are very likely associated with the thick disc. Additionally, the HR1614 moving group and the Hercules and Arcturus stellar streams are discussed and it is concluded that, probably, a large fraction of the groups and streams so far identified in the disc are the result of evolution and interactions within the stellar disc rather than being dissolved stellar clusters or engulfed dwarf galaxies. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. Also based on observations collected at the Nordic Optical Telescope on La Palma, Spain, and at the European Southern Observatories on La Silla and Paranal, Chile, Proposals no. 65.L-0019(B), 67.B-0108(B), 69.B-0277.

  19. Increased dispersion of refractoriness in the absence of QT prolongation in patients with mitral valve prolapse and ventricular arrhythmias.

    PubMed Central

    Tieleman, R. G.; Crijns, H. J.; Wiesfeld, A. C.; Posma, J.; Hamer, H. P.; Lie, K. I.

    1995-01-01

    BACKGROUND--The mechanism responsible for the reported high incidence of ventricular arrhythmias in mitral valve prolapse is not clear. Electrocardiographic studies show an increased occurrence of repolarisation abnormalities on the 12 lead surface electrocardiogram, indicating regional differences in ventricular recovery. The purpose of this study was to investigate whether dispersion of refractoriness was an arrhythmogenic mechanism. METHODS--QT dispersion was measured in 32 patients with echocardiographically documented mitral valve prolapse and ventricular arrhythmias on 24 hour Holter recordings. QT dispersion was defined as the difference between the maximum and minimum average QT interval in any of the 12 leads of the surface electrocardiogram. QT dispersion corrected for heart rate was calculated by Bazett's formula. The results were compared with the data from 32 matched controls without a history of cardiac disease. Patients taking drugs that influence the QT interval and patients with a QRS duration > 120 ms were excluded. RESULTS--QT dispersion was greater in patients with mitral valve prolapse than in matched controls (60 (20) v 39 (11 ms) respectively, P < or = 0.001) as was corrected QT (64 (20 ms) v 43 (12 ms) respectively, P < or = 0.001). There was no significant difference in minimum or maximum QT intervals between the two groups. CONCLUSIONS--QT dispersion on the 12 lead surface electrocardiogram was greater in patients with mitral valve prolapse with ventricular arrhythmias than in normal controls, but the maximum QT interval was not increased. The results accord with the hypothesis that regional shortening and lengthening of repolarisation times in patients with mitral valve prolapse may account for the increased dispersion of refractoriness. PMID:7888258

  20. Robotic mitral valve surgery: overview, methodology, results, and perspective

    PubMed Central

    2016-01-01

    Robotic mitral valve repair began in 1998 and has advanced remarkably. It arose from an interest in reducing patient trauma by operating through smaller incisions with videoscopic assistance. In the United States, following two clinical trials, the FDA approved the daVinci Surgical System in 2002 for intra-cardiac surgery. This device has undergone three iterations, eventuating in the current daVinci XI. At present it is the only robotic device approved for mitral valve surgery. Many larger centers have adopted its use as part of their routine mitral valve repair armamentarium. Although these operations have longer perfusion and arrest times, complications have been either similar or less than other traditional methods. Preoperative screening is paramount and leads to optimal patient selection and outcomes. There are clear contraindications, both relative and absolute, that must be considered. Three-dimensional (3D) echocardiographic studies optimally guide surgeons in operative planning. Herein, we describe the selection criteria as well as our operative management during a robotic mitral valve repair. Major complications are detailed with tips to avoid their occurrence. Operative outcomes from the author’s series as well as those from the largest experiences in the United States are described. They show that robotic mitral valve repair is safe and effective, as well as economically reasonable due to lower costs of hospitalization. Thus, the future of this operative technique is bright for centers adopting the “heart team” approach, adequate clinical volume and a dedicated and experienced mitral repair surgeon. PMID:27942486

  1. Design concepts in lumbar total disc arthroplasty

    PubMed Central

    Bellini, Chiara M.; Zweig, Thomas; Ferguson, Stephen; Raimondi, Manuela T.; Lamartina, Claudio; Brayda-Bruno, Marco; Fornari, Maurizio

    2008-01-01

    The implantation of lumbar disc prostheses based on different design concepts is widely accepted. This paper reviews currently available literature studies on the biomechanics of TDA in the lumbar spine, and is targeted at the evaluation of possible relationships between the aims of TDA and the geometrical, mechanical and material properties of the various available disc prostheses. Both theoretical and experimental studies were analyzed, by a PUBMED search (performed in February 2007, revised in January 2008), focusing on single level TDA. Both semi-constrained and unconstrained lumbar discs seem to be able to restore nearly physiological IAR locations and ROM values. However, both increased and decreased ROM was stated in some papers, unrelated to the clinical outcome. Segmental lordosis alterations after TDA were reported in most cases, for both constrained and unconstrained disc prostheses. An increase in the load through the facet joints was documented, for both semi-constrained and unconstrained artificial discs, but with some contrasting results. Semi-constrained devices may be able to share a greater part of the load, thus protecting the surrounding biological structure from overloading and possible early degeneration, but may be more susceptible to wear. The next level of development will be the biomechanical integration of compression across the motion segment. All these findings need to be supported by long-term clinical outcome studies. PMID:18946684

  2. The debris disc around HIP 17439

    NASA Astrophysics Data System (ADS)

    Schüppler, Christian; Löhne, Torsten; Krivov, Alexander

    2013-07-01

    In the framework of the Herschel Open Time Key Programme DUNES the debris disc around the K2 V star HIP 17439 was observed. In PACS images the disc emission is spatially clearly extended. A simultaneous analysis of photometric observations and radial brightness profiles from the resolved images provides valuable hints for the disc structure. In an analytical model we adopted power laws for the size and radial distribution of the circumstellar dust and tested two different scenarios: (1) a broad dust ring with a radial extent of about 200AU, (2) two independent dust rings separated by a gap of several tens of AU. Both models fit the spectral energy distribution and the radial profiles quite well. In case (1) the parameters found are consistent with dust stemming from an outer planetesimal belt at ~140AU and strong transport mechanisms that drag the particles inward. Model (2) would imply two planetesimal belts, producing a narrow inner and wider outer distribution of dust.

  3. How do accretion discs break?

    NASA Astrophysics Data System (ADS)

    Dogan, Suzan

    2016-07-01

    Accretion discs are common in binary systems, and they are often found to be misaligned with respect to the binary orbit. The gravitational torque from a companion induces nodal precession in misaligned disc orbits. In this study, we first calculate whether this precession is strong enough to overcome the internal disc torques communicating angular momentum. We compare the disc precession torque with the disc viscous torque to determine whether the disc should warp or break. For typical parameters precession wins: the disc breaks into distinct planes that precess effectively independently. To check our analytical findings, we perform 3D hydrodynamical numerical simulations using the PHANTOM smoothed particle hydrodynamics code, and confirm that disc breaking is widespread and enhances accretion on to the central object. For some inclinations, the disc goes through strong Kozai cycles. Disc breaking promotes markedly enhanced and variable accretion and potentially produces high-energy particles or radiation through shocks. This would have significant implications for all binary systems: e.g. accretion outbursts in X-ray binaries and fuelling supermassive black hole (SMBH) binaries. The behaviour we have discussed in this work is relevant to a variety of astrophysical systems, for example X-ray binaries, where the disc plane may be tilted by radiation warping, SMBH binaries, where accretion of misaligned gas can create effectively random inclinations and protostellar binaries, where a disc may be misaligned by a variety of effects such as binary capture/exchange, accretion after binary formation.

  4. Revival of the Jumping Disc

    ERIC Educational Resources Information Center

    Ucke, C.; Schlichting, H-J.

    2009-01-01

    Snap discs made of bimetal have many technical applications as thermostats. Jumping discs are a toy version of such snap discs. Besides giving technical information, we describe physical investigations. We show especially how, through simple measurements and calculations, you can determine the initial speed ([approximately equal to]3.5 m…

  5. Growth of mitral annulus in the pediatric patient after suture annuloplasty of the entire posterior mitral annulus.

    PubMed

    Komoda, Takeshi; Huebler, Michael; Berger, Felix; Hetzer, Roland

    2009-08-01

    When mitral annuloplasty is performed in small children, room for annular growth should be allowed. However, it has not been reported how the valve develops after mitral annuloplasty of the entire posterior annulus. We report a case showing traces of annular growth at redo surgery. A female patient suffering from mitral valve insufficiency due to annular dilatation underwent modified Paneth plasty with Kay-Wooler commissural plication annuloplasty at the age of two years one month. In redo surgery 8.4 years after initial repair, enlargement of the commissural portion of the posterior annulus in addition to enlargement of the anterior leaflet and anterior annulus was observed. Modified Paneth plasty reinforced with a pericardial strip and Kay-Wooler annuloplasty of the posteromedial commissure were performed. Mitral orifice size measured with the Hegar dilator was 18 mm after the re-repair, increasing from 16 mm after the initial repair. Taking into account the normal mitral annulus diameter related to body surface area (BSA) of 16 mm at initial operation and 20 mm at redo surgery, the increase in mitral orifice size from 16 mm to 18 mm in this patient may be regarded as the annular growth in 8.4 years.

  6. Hybrid cervical disc arthroplasty.

    PubMed

    Tu, Tsung-Hsi; Wu, Jau-Ching; Cheng, Henrich; Mummaneni, Praveen V

    2017-01-01

    For patients with multilevel cervical stenosis at nonadjacent segments, one of the traditional approaches has included a multilevel fusion of the abnormal segments as well as the intervening normal segment. In this video we demonstrate an alternative treatment plan with tailored use of a combination of anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) with an intervening skipped level. The authors present the case of a 72-year-old woman with myeloradiculopathy and a large disc herniation with facet joint degeneration at C3-4 and bulging disc at C5-6. After nonoperative treatment failed, she underwent a single-level ACDF at C3-4 and single-level arthroplasty at C5-6, which successfully relieved her symptoms. No intervention was performed at the normal intervening C4-5 segment. By using ACDF combined with arthroplasty, the authors have avoided a 3-level fusion for this patient and maintained the range of motion of 2 disc levels. The video can be found here: https://youtu.be/OrxcPUBvqLk .

  7. The Teddy Bears' Disc.

    ERIC Educational Resources Information Center

    Laurillard, Diana

    1985-01-01

    Reports an evaluation of the Teddy Bear disc, an interactive videodisc developed at the Open University for a second-level course in metallurgy and materials technology. Findings from observation of students utilizing the videodisc are reviewed; successful design features and design problems are considered; and development costs are outlined. (MBR)

  8. Investigation of Product Performance of Al-Metal Matrix Composites Brake Disc using Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Fatchurrohman, N.; Marini, C. D.; Suraya, S.; Iqbal, AKM Asif

    2016-02-01

    The increasing demand of fuel efficiency and light weight components in automobile sectors have led to the development of advanced material parts with improved performance. A specific class of MMCs which has gained a lot of attention due to its potential is aluminium metal matrix composites (Al-MMCs). Product performance investigation of Al- MMCs is presented in this article, where an Al-MMCs brake disc is analyzed using finite element analysis. The objective is to identify the potentiality of replacing the conventional iron brake disc with Al-MMCs brake disc. The simulation results suggested that the MMCs brake disc provided better thermal and mechanical performance as compared to the conventional cast iron brake disc. Although, the Al-MMCs brake disc dissipated higher maximum temperature compared to cast iron brake disc's maximum temperature. The Al-MMCs brake disc showed a well distributed temperature than the cast iron brake disc. The high temperature developed at the ring of the disc and heat was dissipated in circumferential direction. Moreover, better thermal dissipation and conduction at brake disc rotor surface played a major influence on the stress. As a comparison, the maximum stress and strain of Al-MMCs brake disc was lower than that induced on the cast iron brake disc.

  9. Fluid-Structure Interaction Analysis of Papillary Muscle Forces Using a Comprehensive Mitral Valve Model with 3D Chordal Structure.

    PubMed

    Toma, Milan; Jensen, Morten Ø; Einstein, Daniel R; Yoganathan, Ajit P; Cochran, Richard P; Kunzelman, Karyn S

    2016-04-01

    Numerical models of native heart valves are being used to study valve biomechanics to aid design and development of repair procedures and replacement devices. These models have evolved from simple two-dimensional approximations to complex three-dimensional, fully coupled fluid-structure interaction (FSI) systems. Such simulations are useful for predicting the mechanical and hemodynamic loading on implanted valve devices. A current challenge for improving the accuracy of these predictions is choosing and implementing modeling boundary conditions. In order to address this challenge, we are utilizing an advanced in vitro system to validate FSI conditions for the mitral valve system. Explanted ovine mitral valves were mounted in an in vitro setup, and structural data for the mitral valve was acquired with [Formula: see text]CT. Experimental data from the in vitro ovine mitral valve system were used to validate the computational model. As the valve closes, the hemodynamic data, high speed leaflet dynamics, and force vectors from the in vitro system were compared to the results of the FSI simulation computational model. The total force of 2.6 N per papillary muscle is matched by the computational model. In vitro and in vivo force measurements enable validating and adjusting material parameters to improve the accuracy of computational models. The simulations can then be used to answer questions that are otherwise not possible to investigate experimentally. This work is important to maximize the validity of computational models of not just the mitral valve, but any biomechanical aspect using computational simulation in designing medical devices.

  10. RT 3D TEE: Characteristics of Mitral Valve in Ischemic Mitral Regurgitation Evaluated by MVQ Program

    PubMed Central

    Kovalova, Sylva; Necas, Josef

    2011-01-01

    Aim To assess the changes of mitral valve (MV) in ischemic mitral regurgitation (IMR) using Mitral Valve Quantification (MVQ) program. Methods We examined 46 patients (18 women) with IMR aged 45-86 and a control group of 33 healthy individuals (14 women) aged 18-88. Following parameters were assessed: Area of minimal surface spanning annulus (A3), annulus height (h), tenting height (Th), exposed area of anterior (AL), posterior (PL) and both leaflets (BL), ejection fraction of the left ventricle (LV EF), regurgitation volume (RV) and BL/A3, AL/A3, PL/A3 ratios. The normal range of BL/A3 ratio was defined as the average ± 2SD of control group. The study group was separated into subgroup 1 with BL/A3 ratio within normal values and subgroup 2 with pathological BL/A3 ratio. Corresponding parameters of IMR group were compared to the controls and both subgroups were compared to each other using Student t-test. Results In IMR group, as compared to the controls, A3, AL, PL, BL as well as BL/A3, AL/A3, PL/A3 ratios and Th were significantly increased, conversely, h and LV EF was significantly decreased. In the subgroup 2 as compared to the subgroup 1 there was significant increase of Th, BL, AL and PL, while EF LV was significantly decreased. There was no significant difference between these subgroups in A3, h and RV. Conclusion In ischemic MV remodeling two stages were identified without relation to the severity of IMR. The first stage was mainly influenced by the LV dilatation while LV remodeling was more important in the second stage.

  11. Surgery for rheumatic mitral valve disease in sub-saharan African countries: why valve repair is still the best surgical option.

    PubMed

    Mvondo, Charles Mve; Pugliese, Marta; Giamberti, Alessandro; Chelo, David; Kuate, Liliane Mfeukeu; Boombhi, Jerome; Dailor, Ellen Marie

    2016-01-01

    Rheumatic valve disease, a consequence of acute rheumatic fever, remains endemic in developing countries in the sub-Saharan region where it is the leading cause of heart failure and cardiovascular death, involving predominantly a young population. The involvement of the mitral valve is pathognomonic and mitral surgery has become the lone therapeutic option for the majority of these patients. However, controversies exist on the choice between valve repair or prosthetic valve replacement. Although the advantages of mitral valve repair over prosthetic valve replacement in degenerative mitral disease are well established, this has not been the case for rheumatic lesions, where the use of prosthetic valves, specifically mechanical devices, even in poorly compliant populations remains very common. These patients deserve more accurate evaluation in the choice of the surgical strategy which strongly impacts the post-operative outcomes. This report discusses the factors supporting mitral repair surgery in rheumatic disease, according to the patients' characteristics and the effectiveness of the current repair techniques compared to prosthetic valve replacement in developing countries.

  12. Analytical Investigation on Squeal Phenomena Generated in Bicycle Disc Brakes

    NASA Astrophysics Data System (ADS)

    Nakae, Takashi; Sueoka, Atsuo; Ryu, Takahiro

    The squeal phenomenon is often generated in bicycle disc brakes. This paper deals analytically with the generation mechanism and the criterion of whether or not the squeal occurs. According to the experimental studies, it has been made clear that the squeal is mainly in-plane vibration in the direction of disc surface with the frequency about 1kHz caused by frictional characteristics with negative slope with respect to the relative velocity. An analytical model of the bicycle disc brake system has been devised to confirm the experimental results, in which a coupled in-plane and out-of-plane vibrating system is composed of the disc, hub, caliper and spokes. The resulting frequency of squeal and the unstable vibration modes of the disc and spokes from the analytical model agreed well with the experimental results.

  13. Mutations in DCHS1 cause mitral valve prolapse.

    PubMed

    Durst, Ronen; Sauls, Kimberly; Peal, David S; deVlaming, Annemarieke; Toomer, Katelynn; Leyne, Maire; Salani, Monica; Talkowski, Michael E; Brand, Harrison; Perrocheau, Maëlle; Simpson, Charles; Jett, Christopher; Stone, Matthew R; Charles, Florie; Chiang, Colby; Lynch, Stacey N; Bouatia-Naji, Nabila; Delling, Francesca N; Freed, Lisa A; Tribouilloy, Christophe; Le Tourneau, Thierry; LeMarec, Hervé; Fernandez-Friera, Leticia; Solis, Jorge; Trujillano, Daniel; Ossowski, Stephan; Estivill, Xavier; Dina, Christian; Bruneval, Patrick; Chester, Adrian; Schott, Jean-Jacques; Irvine, Kenneth D; Mao, Yaopan; Wessels, Andy; Motiwala, Tahirali; Puceat, Michel; Tsukasaki, Yoshikazu; Menick, Donald R; Kasiganesan, Harinath; Nie, Xingju; Broome, Ann-Marie; Williams, Katherine; Johnson, Amanda; Markwald, Roger R; Jeunemaitre, Xavier; Hagege, Albert; Levine, Robert A; Milan, David J; Norris, Russell A; Slaugenhaupt, Susan A

    2015-09-03

    Mitral valve prolapse (MVP) is a common cardiac valve disease that affects nearly 1 in 40 individuals. It can manifest as mitral regurgitation and is the leading indication for mitral valve surgery. Despite a clear heritable component, the genetic aetiology leading to non-syndromic MVP has remained elusive. Four affected individuals from a large multigenerational family segregating non-syndromic MVP underwent capture sequencing of the linked interval on chromosome 11. We report a missense mutation in the DCHS1 gene, the human homologue of the Drosophila cell polarity gene dachsous (ds), that segregates with MVP in the family. Morpholino knockdown of the zebrafish homologue dachsous1b resulted in a cardiac atrioventricular canal defect that could be rescued by wild-type human DCHS1, but not by DCHS1 messenger RNA with the familial mutation. Further genetic studies identified two additional families in which a second deleterious DCHS1 mutation segregates with MVP. Both DCHS1 mutations reduce protein stability as demonstrated in zebrafish, cultured cells and, notably, in mitral valve interstitial cells (MVICs) obtained during mitral valve repair surgery of a proband. Dchs1(+/-) mice had prolapse of thickened mitral leaflets, which could be traced back to developmental errors in valve morphogenesis. DCHS1 deficiency in MVP patient MVICs, as well as in Dchs1(+/-) mouse MVICs, result in altered migration and cellular patterning, supporting these processes as aetiological underpinnings for the disease. Understanding the role of DCHS1 in mitral valve development and MVP pathogenesis holds potential for therapeutic insights for this very common disease.

  14. Echocardiographic assessment of left ventricular filling after mitral valve surgery.

    PubMed Central

    St John Sutton, M G; Traill, T A; Ghafour, A S; Brown, D J; Gibson, D G

    1977-01-01

    In order to investigate the functional effects of mitral valve surgery, echocardiograms showing left ventricular dimension were recorded and digitised in 14 normal subjects and 129 patients after mitral valve surgery. Measurements were made of peak rate of increase of dimension (dD/dt) and duration of rapid filling, studies on left ventriculograms in 36 patients having shown close correlation between these values and changes in cavity volume. In 14 patients with mitral stenosis, peak dD/dt was reduced to 7-2 +/ 1-5 cm/s, and filling period prolonged to 330 +/- 65 ms, compared with normal (16-0 +/- 3-2 cm/s, and 160 +/- 50 ms, respectively), and after mitral valvotomy, these values improved significantly (10-4 +/- 2-7 cm/s and 245 +/- 55 ms). Characteristic abnormalities were found in 67 patients with mitral prostheses. Values for the Björk-Shiley (10-5 +/- 4-2 cm/s and 180 +/- 80 ms) and Hancock (10-3 +/- 3-7 cm/s, 245 +/- 80 ms) values were similar, and both superior to the Starr-Edwards (7-4 +/- 3-0 cm/s, 295 +/- 105 ms). Results after mitral valve repair in 30 cases were not significantly different from normal (14-4 +/- 5-0 cm/s, 170 +/- 50 ms). Values outside the 95 per cent confidence limits for the valve in question allowed diagnosis of value malfunction in 18 cases. The method is value in comparing different operative procedures and in following up patients after mitral valve surgery. PMID:603728

  15. Mutations in DCHS1 Cause Mitral Valve Prolapse

    PubMed Central

    Durst, Ronen; Sauls, Kimberly; Peal, David S; deVlaming, Annemarieke; Toomer, Katelynn; Leyne, Maire; Salani, Monica; Talkowski, Michael E.; Brand, Harrison; Perrocheau, Maëlle; Simpson, Charles; Jett, Christopher; Stone, Matthew R.; Charles, Florie; Chiang, Colby; Lynch, Stacey N.; Bouatia-Naji, Nabila; Delling, Francesca N.; Freed, Lisa A.; Tribouilloy, Christophe; Le Tourneau, Thierry; LeMarec, Hervé; Fernandez-Friera, Leticia; Solis, Jorge; Trujillano, Daniel; Ossowski, Stephan; Estivill, Xavier; Dina, Christian; Bruneval, Patrick; Chester, Adrian; Schott, Jean-Jacques; Irvine, Kenneth D.; Mao, Yaopan; Wessels, Andy; Motiwala, Tahirali; Puceat, Michel; Tsukasaki, Yoshikazu; Menick, Donald R.; Kasiganesan, Harinath; Nie, Xingju; Broome, Ann-Marie; Williams, Katherine; Johnson, Amanda; Markwald, Roger R.; Jeunemaitre, Xavier; Hagege, Albert; Levine, Robert A.; Milan, David J.; Norris, Russell A.; Slaugenhaupt, Susan A.

    2015-01-01

    SUMMARY Mitral valve prolapse (MVP) is a common cardiac valve disease that affects nearly 1 in 40 individuals1–3. It can manifest as mitral regurgitation and is the leading indication for mitral valve surgery4,5. Despite a clear heritable component, the genetic etiology leading to non-syndromic MVP has remained elusive. Four affected individuals from a large multigenerational family segregating non-syndromic MVP underwent capture sequencing of the linked interval on chromosome 11. We report a missense mutation in the DCHS1 gene, the human homologue of the Drosophila cell polarity gene dachsous (ds) that segregates with MVP in the family. Morpholino knockdown of the zebrafish homolog dachsous1b resulted in a cardiac atrioventricular canal defect that could be rescued by wild-type human DCHS1, but not by DCHS1 mRNA with the familial mutation. Further genetic studies identified two additional families in which a second deleterious DCHS1 mutation segregates with MVP. Both DCHS1 mutations reduce protein stability as demonstrated in zebrafish, cultured cells, and, notably, in mitral valve interstitial cells (MVICs) obtained during mitral valve repair surgery of a proband. Dchs1+/− mice had prolapse of thickened mitral leaflets, which could be traced back to developmental errors in valve morphogenesis. DCHS1 deficiency in MVP patient MVICs as well as in Dchs1+/− mouse MVICs result in altered migration and cellular patterning, supporting these processes as etiological underpinnings for the disease. Understanding the role of DCHS1 in mitral valve development and MVP pathogenesis holds potential for therapeutic insights for this very common disease. PMID:26258302

  16. ANP and BNP plasma levels in patients with rheumatic mitral stenosis after percutaneous balloon mitral valvuloplasty

    PubMed Central

    Rużyłło, Witold; Chmielak, Zbigniew; Opalińska-Ciszek, Ewa; Janas, Jadwiga; Hoffman, Piotr; Hryniewiecki, Tomasz; Grzybowski, Jacek

    2017-01-01

    Introduction Atrial (ANP) and B-type (BNP) natriuretic peptides are hormones secreted by the heart as a response to volume expansion and pressure overload. Aim To assess the changes of ANP and BNP after percutaneous balloon mitral valvuloplasty (PBMV) and to investigate factors associated with endpoints. Material and methods The study included 96 patients (90.7% females, age 51.6 ±12.2 years) with rheumatic mitral valve stenosis (mitral valve area (MVA) 1.18 (1.01–1.33) cm2, mean mitral gradient (MMG) 8.2 (7.1–9.2) mm Hg, NYHA 2.09 (1.9–2.5)). Patients were followed up for 29.1 months for the search of endpoints. Results The PBMV was successful in all cases. After the procedure MVA increased (1.18–1.78 cm2, p < 0.01) and pulmonary capillary wedge pressure (PCWP) decreased (29.8–21.8 mm Hg, p < 0.01). Concentration of ANP significantly rose 30 min after the PBMV (79.2 vs. 134.2 pg/ml, p = 0.012) and dropped significantly after 24 h (134.2 vs. 70.4 pg/ml, p = 0.01). Furthermore, after 36 months concentration of ANP did not differ from the baseline value (p = NS). BNP concentration at day 1 was lower than at baseline (94.5 vs. 80.2 pg/ml, p = 0.032). Moreover, during the follow-up period BNP continued to fall at all time points. In univariate analysis parameters associated with endpoint occurrence were baseline PAP (p = 0.023), baseline PCWP (p = 0.022), baseline NYHA (p = 0.041) and increase in 6-minute walk test (6MWT) (p = 0.043). In multivariate analysis the only factor associated with endpoint occurrence was baseline NYHA (HR = 1.52, 95% CI: –1.3–1.91, p = 0.022). Conclusions Patients with MS had increased levels of both BNP and ANP. Baseline NYHA class was found to be associated with outcomes after the procedure. PMID:28344613

  17. Quantitative Evaluation of Mitral Regurgitation Secondary to Mitral Valve Prolapse by Magnetic Resonance Imaging and Echocardiography.

    PubMed

    Le Goffic, Caroline; Toledano, Manuel; Ennezat, Pierre-Vladimir; Binda, Camille; Castel, Anne-Laure; Delelis, François; Graux, Pierre; Tribouilloy, Christophe; Maréchaux, Sylvestre

    2015-11-01

    The present prospective study was designed to evaluate the accuracy of quantitative assessment of mitral regurgitant fraction (MRF) by echocardiography and cardiac magnetic resonance imaging (cMRI) in the modern era using as reference method the blinded multiparametric integrative assessment of mitral regurgitation (MR) severity. 2-Dimensional (2D) and 3-dimensional (3D) MRF by echocardiography (2D echo MRF and 3D echo MRF) were obtained by measuring the difference in left ventricular (LV) total stroke volume (obtained from either 2D or 3D acquisition) and aortic forward stroke volume normalized to LV total stroke volume. MRF was calculated by cMRI using either (1) (LV stroke volume - systolic aortic outflow volume by phase contrast)/LV stroke volume (cMRI MRF [volumetric]) or (2) (mitral inflow volume - systolic aortic outflow volume)/mitral inflow volume (cMRI MRF [phase contrast]). Six patients had 1 + MR, 6 patients had 2 + MR, 12 patients had 3 + MR, and 10 had 4 + MR. A significant correlation was observed between MR grading and 2D echo MRF (r = 0.60, p <0.0001) and 3D echo MRF (r = 0.79, p <0.0001), cMRI MRF (volumetric) (r = 0.87, p <0.0001), and cMRI MRF (phase contrast r = 0.72, p <0.001). The accuracy of MRF for the diagnosis of MR ≥3+ or 4+ was the highest with cMRI MRF (volumetric) (area under the receiver-operating characteristic curve [AUC] = 0.98), followed by 3D echo MRF (AUC = 0.96), 2D echo MRF (AUC = 0.90), and cMRI MRF (phase contrast; AUC = 0.83). In conclusion, MRF by cMRI (volumetric method) and 3D echo MRF had the highest diagnostic value to detect significant MR, whereas the diagnostic value of 2D echo MRF and cMRI MRF (phase contrast) was lower. Hence, the present study suggests that both cMRI (volumetric method) and 3D echo represent best approaches for calculating MRF.

  18. Impact of mitral geometry and global afterload on improvement of mitral regurgitation after trans-catheter aortic valve implantation

    PubMed Central

    Dworakowski, R; Kogoj, P; Reiken, J; Kenny, C; MacCarthy, P; Wendler, O; Monaghan, M J

    2016-01-01

    Objective To assess the impact of mitral geometry, left ventricular (LV) remodelling and global LV afterload on mitral regurgitation (MR) after trans-catheter aortic valve implantation (TAVI). Methods In this study, 60 patients who underwent TAVI were evaluated by 3D echocardiography at baseline, 1 month and 6 months after procedure. The proportional change in MR following TAVI was determined by examining the percentage change in vena contracta (VC) at 6 months. Patients having a significant reduction of at least 30% in VC were defined as good responders (GR) and the remaining patients were defined as poor responders (PR). Results After 6 months of TAVI, 27 (45%) patients were GR and 33 (55%) were PR. There was a significant decrease in 3DE-derived mitral annular diameter and area (P = 0.001), mitral valve tenting area (TA) (P = 0.05), and mitral papillary muscle dyssynchrony index (DSI) (P = 0.05) in the GR group. 3DE-derived LVESV (P = 0.016), LV mass (P = 0.001) and LV DSI, (P = 0.001) were also improved 6 months after TAVI. In addition, valvulo-arterial impedance (ZVA) was significantly higher at baseline in patients with PR (P = 0.028). 3DE-derived mitral annular area (β: 0.47, P = 0.04), mitral papillary DSI (β: −0.65, P = 0.012) and ZVA (β: 0.45, P = 0.028) were the strongest independent parameters that could predict the reduction of functional MR after TAVI. Conclusion GR patients demonstrate more regression in mitral annulus area and diameter after significant decrease in high LVEDP and trans-aortic gradients with TAVI. PR patients appear to have increased baseline ZVA, mitral valve tenting and restriction in mitral valve coaptation. These factors are important for predicting the impact of TAVI on pre-existing MR. PMID:27457965

  19. Diastolic murmurs in the presence of Starr-Edwards mitral prosthesis.

    PubMed

    Schaffer, R A; McAnulty, J H; Starr, A; Rahimtoola, S H

    1975-03-01

    Diastolic murmurs associated with the Starr-Edwards mitral prosthesis have not been described previously. In this report, five patients with mitral prostheses are described in whom apical mid-diastolic and presystolic murmurs resulted from two different causes. Three patients had clots obstructing the prosthetic orifice. The other two had normally functioning protheses and moderately severe aortic insufficiency. The occurrence of mid-diastolic and presystolic murmurs in the presence of a normally functioning prosthetic mitral valve demonstrates that 1) the mid-diastolic Austin Flint murmur can occur in the absence of incomplete mitral valve opening, premature mitral valve closure, vibrating mitral leaflets, or relative mitral stenosis and 2) the presystolic Austin Flint murmur can occur in the absence of incomplete valve opening or presystolic mitral regurgitation. However, the presystolic murmur was associated with early closure movement of the presthetic poppet.

  20. Noninvasive radioisotopic technique for detection of platelet deposition in mitral valve prosthesis and renal microembolism in dogs

    SciTech Connect

    Dewanjee, M.K.; Kaye, M.P.; Fuster, V.; Rao, S.A.

    1980-01-01

    At 24 hrs after implantation of Bjoerk-Shiley mitral prosthesis in 5 dogs, in vivo images were obtained with a gamma camera after intravenous administration (0.5-0.6 mCi) one hour postoperatively of autologous Indium-111-labeled platelets. The site of platelet deposition in the teflon ring and perivascular damaged cardiac tissue is clearly delineated in the scintiphoto. In vitro biodistribution (mean % +/- SD of injected dose) at 24 hrs after injection of the 5 implanted and 7 normal dogs performed with a gamma counter demonstrated that (45.1 +/- 10.6)% and (0.7 +/- 0.4)% were in blood and kidneys in normal dogs and (28.5 +/- 6.8)%, (1.6 +/- 0.6)%, (0.3 +/- 0.1)%, and (0.2 +/- 0.1)% were in blood, kidneys, teflon rings, and perivascular damaged cardiac tissue, respectively. The strut and pyrolytic carbon-coated disc retained only (0.0033 +/- 0.0004)% and (0.0031 +/- 0.0003)%, respectively. There was a 2.3-fold increase of labeled platelets in kidneys of implanted dogs due to renal trapping of microembolism. Also, three- to fivefold increase in ratios of lung, brain, cardiac, and skeletal muscle to blood indicates that internal organs and whole body work as filter for microembolism generated by cardiovascular surgery and mitral prosthesis. Twenty percent of the administered platelets are consumed in surgical repair of damaged tissue. Indium-111-labeled platelets thus provide a sensitive marker for noninvasive imaging of Bjoerk-Shiley mitral prosthesis, thromboembolism after implantation of prosthetic device, and in vitro quantitation of surgical consumption.

  1. Effect of the prosthetic mitral valve on vortex dynamics and turbulence of the left ventricular flow

    NASA Astrophysics Data System (ADS)

    Querzoli, G.; Fortini, S.; Cenedese, A.

    2010-04-01

    Mechanical heart valves implanted in mitral position have a great effect on the ventricular flow. Changes include alteration of the dynamics of the vortical structures generated during the diastole and the onset of turbulence, possibly affecting the efficiency of the heart pump or causing blood cell damage. Modifications to the hemodynamics in the left ventricle, when the inflow through the mitral orifice is altered, were investigated in vitro using a silicone rubber, flexible ventricle model. Velocity fields were measured in space and time by means of an image analysis technique: feature tracking. Three series of experiments were performed: one with a top hat inflow velocity profile (schematically resembling physiological conditions), and two with mechanical prosthetic valves of different design, mounted in mitral position—one monoleaflet and the other bileaflet. In each series of runs, two different cardiac outputs have been examined by changing the stroke volume. The flow was investigated in terms of phase averaged velocity field and second order moments of turbulent fluctuations. Results show that the modifications in the transmitral flow change deeply the interaction between the coherent structures generated during the first phase of the diastole and the incoming jet during the second diastolic phase. Top hat inflow gives the coherent structures which are optimal, among the compared cases, for the systolic function. The flow generated by the bileaflet valve preserves most of the beneficial features of the top hat inflow, whereas the monoleaflet valve generates a strong jet which discourages the permanence of large coherent structures at the end of the diastole. Moreover, the average shear rate magnitudes induced by the smoother flow pattern of the case of top hat inflow are nearly halved in comparison with the values measured with the mechanical valves. Finally, analysis of the turbulence statistics shows that the monoleaflet valves yield higher turbulence

  2. Tissue Engineering a Biological Repair Strategy for Lumbar Disc Herniation

    PubMed Central

    O'Connell, Grace D.; Leach, J. Kent; Klineberg, Eric O.

    2015-01-01

    Abstract The intervertebral disc is a critical part of the intersegmental soft tissue of the spinal column, providing flexibility and mobility, while absorbing large complex loads. Spinal disease, including disc herniation and degeneration, may be a significant contributor to low back pain. Clinically, disc herniations are treated with both nonoperative and operative methods. Operative treatment for disc herniation includes removal of the herniated material when neural compression occurs. While this strategy may have short-term advantages over nonoperative methods, the remaining disc material is not addressed and surgery for mild degeneration may have limited long-term advantage over nonoperative methods. Furthermore, disc herniation and surgery significantly alter the mechanical function of the disc joint, which may contribute to progression of degeneration in surrounding tissues. We reviewed recent advances in tissue engineering and regenerative medicine strategies that may have a significant impact on disc herniation repair. Our review on tissue engineering strategies focuses on cell-based and inductive methods, each commonly combined with material-based approaches. An ideal clinically relevant biological repair strategy will significantly reduce pain and repair and restore flexibility and motion of the spine. PMID:26634189

  3. Relief of mitral incompetence by selective intracoronary thrombolysis in hyperacute myocardial infarction.

    PubMed

    Keltai, M; Palik, I; Rozsa, Z; Szente, A

    1985-01-01

    Left ventriculography and coronary arteriography were performed in 47 patients with hyperacute myocardial infarction prior to recanalization of the infarct-related vessel. Mitral regurgitation was found in ten patients. After successful recanalization, left ventriculography was repeated in eight of the ten patients with mitral incompetence, and the mitral regurgitation had disappeared in seven. Selective intracoronary thrombolysis resulted in improved left ventricular function and disappearance of mitral incompetence.

  4. Relationship between the physical size, incompetence, and stenosis of prosthetic mitral valves

    PubMed Central

    Wright, J. T. M.; Temple, L. J.

    1972-01-01

    One each of 17 commercially available prosthetic mitral valves has been subjected to in vitro testing using a pulse duplicator. Measurements of mean diastolic pressure difference, incompetence, dimensions, mechanical movements, and turbulence were made, and the quality of manufacture was examined. Although most valves would be effective in the treatment of incompetence, only those with large orifice diameters produced no significant stenosis. All the valves tested were in clinical use at some time in the period 1966-71. Most of the prostheses were obtained in 1968 or 1969. Many of this group showed a manufacturing standard which was less than impeccable. Images PMID:5039443

  5. New Presentation of Hemolysis After Papillary Muscles Approximation for Mitral Valve Repair.

    PubMed

    Sarraj, Anas; Calle Valda, Corazón-Mabel; Muñoz, Daniel-Edgardo; Reyes, Guillermo

    2017-04-01

    Hemolysis is a well-recognized complication after prosthetic valve replacement, especially with perivalvular leaks. Hemolytic anemia associated with mitral valve (MV) repair is less common. We report the case of a young man with severe hemolytic anemia caused by turbulence of blood flow through a very small quadrangle orifice due to early failure of MV repair. The patient underwent redo MV biologic prosthesis replacement and tricuspid valve annuloplasty. The hemolysis completely disappeared few months later. In this case, we describe a new presentation of mechanical hemolysis due to early failure of MV repair that has not been described in the literature.

  6. LUMBAR DISC HERNIATION

    PubMed Central

    Vialle, Luis Roberto; Vialle, Emiliano Neves; Suárez Henao, Juan Esteban; Giraldo, Gustavo

    2015-01-01

    Lumbar disc herniation is the most common diagnosis among the degenerative abnormalities of the lumbar spine (affecting 2 to 3% of the population), and is the principal cause of spinal surgery among the adult population. The typical clinical picture includes initial lumbalgia, followed by progressive sciatica. The natural history of disc herniation is one of rapid resolution of the symptoms (four to six weeks). The initial treatment should be conservative, managed through medication and physiotherapy, sometimes associated with percutaneous nerve root block. Surgical treatment is indicated if pain control is unsuccessful, if there is a motor deficit greater than grade 3, if there is radicular pain associated with foraminal stenosis, or if cauda equina syndrome is present. The latter represents a medical emergency. A refined surgical technique, with removal of the extruded fragment and preservation of the ligamentum flavum, resolves the sciatic symptoms and reduces the risk of recurrence over the long term. PMID:27019834

  7. Mechanotransduction in intervertebral discs

    PubMed Central

    Tsai, Tsung-Ting; Cheng, Chao-Min; Chen, Chien-Fu; Lai, Po-Liang

    2014-01-01

    Mechanotransduction plays a critical role in intracellular functioning—it allows cells to translate external physical forces into internal biochemical activities, thereby affecting processes ranging from proliferation and apoptosis to gene expression and protein synthesis in a complex web of interactions and reactions. Accordingly, aberrant mechanotransduction can either lead to, or be a result of, a variety of diseases or degenerative states. In this review, we provide an overview of mechanotransduction in the context of intervertebral discs, with a focus on the latest methods of investigating mechanotransduction and the most recent findings regarding the means and effects of mechanotransduction in healthy and degenerative discs. We also provide some discussion of potential directions for future research and treatments. PMID:25267492

  8. Mitral valve repair: an echocardiographic review: Part 2.

    PubMed

    Maslow, Andrew

    2015-04-01

    Echocardiographic imaging of the mitral valve before and immediately after repair is crucial to the immediate and long-term outcome. Prior to mitral valve repair, echocardiographic imaging helps determine the feasibility and method of repair. After the repair, echocardiographic imaging displays the new baseline anatomy, assesses function, and determines whether or not further management is necessary. Three-dimensional imaging has improved the assessment of the mitral valve and facilitates communication with the surgeon by providing the surgeon with an image that he/she might see upon opening up the atrium. Further advancements in imaging will continue to improve the understanding of the function and dysfunction of the mitral valve both before and after repair. This information will improve treatment options, timing of invasive therapies, and advancements of repair techniques to yield better short- and long-term patient outcomes. The purpose of this review was to connect the echocardiographic evaluation with the surgical procedure. Bridging the pre- and post-CPB imaging with the surgical procedure allows a greater understanding of mitral valve repair.

  9. Percutaneous transluminal balloon dilatation of the mitral valve in pregnancy.

    PubMed Central

    Smith, R; Brender, D; McCredie, M

    1989-01-01

    Pregnancy can cause life threatening complications in women with mitral stenosis, and there is a substantial risk of fetal death if valvotomy under cardiopulmonary bypass is required. A patient is described in whom pulmonary oedema developed after delivery of her first child by caesarean section 13 months previously. Subsequent cardiac catheterisation showed severe mitral stenosis (valve area 0.96 cm2, valve gradient 12 mm Hg, pulmonary artery pressure 30/16 mm Hg). Before valvotomy could be performed the patient again became pregnant and presented in pulmonary oedema at twenty two weeks' gestation. Medical treatment was unsuccessful and she underwent percutaneous transluminal balloon dilatation of the mitral valve. This increased the valve area to 1.78 cm2 and reduced the transmitral gradient to 6 mm Hg. The procedure was uncomplicated, and she remained symptom free on no medication. She delivered vaginally at 37 weeks' gestation. Percutaneous transluminal balloon dilatation of the mitral valve is a safe and effective alternative to mitral valvotomy in pregnancy. PMID:2757867

  10. Usefulness of radionuclide angiocardiography in predicting stenotic mitral orifice area

    SciTech Connect

    Burns, R.J.; Armitage, D.L.; Fountas, P.N.; Tremblay, P.C.; Druck, M.N.

    1986-12-01

    Fifteen patients with pure mitral stenosis (MS) underwent high-temporal-resolution radionuclide angiocardiography for calculation of the ratio of peak left ventricular (LV) filling rate divided by mean LV filling rate (filling ratio). Whereas LV filling normally occurs in 3 phases, in MS it is more uniform. Thus, in 13 patients the filling ratio was below the normal range of 2.21 to 2.88 (p less than 0.001). In 11 patients in atrial fibrillation, filling ratio divided by mean cardiac cycle length and by LV ejection fraction provided good correlation (r = 0.85) with modified Gorlin formula derived mitral area and excellent correlation with echocardiographic mitral area (r = 0.95). Significant MS can be detected using radionuclide angiocardiography to calculate filling ratio. In the absence of the confounding influence of atrial systole calculation of 0.14 (filling ratio divided by cardiac cycle length divided by LV ejection fraction) + 0.40 cm2 enables accurate prediction of mitral area (+/- 4%). Our data support the contention that the modified Gorlin formula, based on steady-state hemodynamics, provides less certain estimates of mitral area for patients with MS and atrial fibrillation, in whom echocardiography and radionuclide angiocardiography may be more accurate.

  11. [Study of left ventricular function in valvular cardiopathies (mitral insufficiency and aortic insufficiency].

    PubMed

    Herreman, F; Brun, P; Cannet, G; Savin, E; Vannier, D

    1974-10-01

    A study of the left ventricular function based on the haemodynamic data combined with those provided by biplane cineangiography was performed in 35 cases with left ventricular volume overload (20 cases of mitral incompetence and 15 of aortic insufficiency). The importance of the haemodynamic changes and of the adaptation mechanisms set up were described. The more intense dilatation-hypertrophy of aortic incompetence than of mitral incompetence plays an essential part. The role of Starling's mechanism is underlined. Estimation of the contractile value of the myocardium, taken into account the mechanical overload and the conditions of late-diastolic lengthening of the fibre and of impedance to left ventricular ejection was determined. An obvious myocardial failure, demonstrated in approximately one third of the cases, by determination of some contractility indices estimated in the ejection phase, Vf sigma max in particular, the only one valid in the presence of valvular regurgitation. In the other cases, the moderate decrease of myocardial contractility was masked by compensatory mechanisms.

  12. Cost effectiveness of robotic mitral valve surgery

    PubMed Central

    2017-01-01

    Significant technological advances have led to an impressive evolution in mitral valve surgery over the last two decades, allowing surgeons to safely perform less invasive operations through the right chest. Most new technology comes with an increased upfront cost that must be measured against postoperative savings and other advantages such as decreased perioperative complications, faster recovery, and earlier return to preoperative level of functioning. The Da Vinci robot is an example of such a technology, combining the significant benefits of minimally invasive surgery with a “gold standard” valve repair. Although some have reported that robotic surgery is associated with increased overall costs, there is literature suggesting that efficient perioperative care and shorter lengths of stay can offset the increased capital and intraoperative expenses. While data on current cost is important to consider, one must also take into account future potential value resulting from technological advancement when evaluating cost-effectiveness. Future refinements that will facilitate more effective surgery, coupled with declining cost of technology will further increase the value of robotic surgery compared to traditional approaches. PMID:28203539

  13. Anatomical features of acute mitral valve repair dysfunction: Additional value of three-dimensional echocardiography.

    PubMed

    Derkx, Salomé; Nguyen, Virginia; Cimadevilla, Claire; Verdonk, Constance; Lepage, Laurent; Raffoul, Richard; Nataf, Patrick; Vahanian, Alec; Messika-Zeitoun, David

    2017-03-01

    Recurrence of mitral regurgitation after mitral valve repair is correlated with unfavourable left ventricular remodelling and poor outcome. This pictorial review describes the echocardiographic features of three types of acute mitral valve repair dysfunction, and the additional value of three-dimensional echocardiography.

  14. Opening snap and isovolumic relaxation period in relation to mitral valve flow in patients with mitral stenosis. Significance of A2--OS interval.

    PubMed Central

    Kalmanson, D; Veyrat, C; Bernier, A; Witchitz, S; Chiche, P

    1976-01-01

    In 15 patients with pure or predominant mitral stenosis and in a control group of 11 patients without mitral stenosis the blood flow velocity through the mitral valve orifice was recorded by means of a directional Doppler ultrasound velocity catheter introduced transeptally and positioned in the orifice of the mitral valve. A simultaneous surface phonocardiogram was obtained. The timing of the mitral opening snap in relation to the blood velocity record of the flow through the valve supported the hypothesis that the opening snap is due to a sudden tensing of the valve leaflets by the chordae tendineae. Determination of the exact time of mitral valve opening, made possible by the blood velocity record, led to the division of the classical A2-0S interval (aortic valve closure to opening snap) into two components representing respectively the diastolic isovolumic relaxation period and the time of excursion of the mitral valve cusps. The durations of the isovolumic relaxation period were compared with those in the control patients and were found to correlate with the severity of the mitral stenosis, whereas those of the excursion time of the mitral cusps were influenced by the presence or absence of mitral valve calcification. PMID:1259828

  15. Total disc replacement.

    PubMed

    Vital, J-M; Boissière, L

    2014-02-01

    Total disc replacement (TDR) (partial disc replacement will not be described) has been used in the lumbar spine since the 1980s, and more recently in the cervical spine. Although the biomechanical concepts are the same and both are inserted through an anterior approach, lumbar TDR is conventionally indicated for chronic low back pain, whereas cervical TDR is used for soft discal hernia resulting in cervicobrachial neuralgia. The insertion technique must be rigorous, with precise centering in the disc space, taking account of vascular anatomy, which is more complex in the lumbar region, particularly proximally to L5-S1. All of the numerous studies, including prospective randomized comparative trials, have demonstrated non-inferiority to fusion, or even short-term superiority regarding speed of improvement. The main implant-related complication is bridging heterotopic ossification with resulting loss of range of motion and increased rates of adjacent segment degeneration, although with an incidence lower than after arthrodesis. A sufficiently long follow-up, which has not yet been reached, will be necessary to establish definitively an advantage for TDR, particularly in the cervical spine.

  16. Polarimetric microlensing of circumstellar discs

    NASA Astrophysics Data System (ADS)

    Sajadian, Sedighe; Rahvar, Sohrab

    2015-12-01

    We study the benefits of polarimetry observations of microlensing events to detect and characterize circumstellar discs around the microlensed stars located at the Galactic bulge. These discs which are unresolvable from their host stars make a net polarization effect due to their projected elliptical shapes. Gravitational microlensing can magnify these signals and make them be resolved. The main aim of this work is to determine what extra information about these discs can be extracted from polarimetry observations of microlensing events in addition to those given by photometry ones. Hot discs which are closer to their host stars are more likely to be detected by microlensing, owing to more contributions in the total flux. By considering this kind of discs, we show that although the polarimetric efficiency for detecting discs is similar to the photometric observation, but polarimetry observations can help to constraint the disc geometrical parameters e.g. the disc inner radius and the lens trajectory with respect to the disc semimajor axis. On the other hand, the time-scale of polarimetric curves of these microlensing events generally increases while their photometric time-scale does not change. By performing a Monte Carlo simulation, we show that almost four optically thin discs around the Galactic bulge sources are detected (or even characterized) through photometry (or polarimetry) observations of high-magnification microlensing events during 10-yr monitoring of 150 million objects.

  17. The use of a high-power laser on swine mitral valve chordae tendineae.

    PubMed

    Pinto, Nathali Cordeiro; Chavantes, M Cristina; Zezell, Denise; Deana, Alessandro; Benetti, Carolina; Marcos, Rodrigo Labat; Lopes, Luciana Almeida; Martins, Rodrigo A B Lopes; Aiello, Vera Demarchi; Jatene, Fabio Biscegli; Pomerantzeff, Pablo M A

    2016-08-01

    Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation). Laser surgery was performed under controlled conditions, using following parameters: λ = 980-nm wavelength, power = 3 W, and energy = 60 J. A mechanical test machine was used in combination with a subsequent histological study to measure chordae tensile properties. A histological analysis demonstrated a typical collagen bundle arrangement in the control group; however, under a particular reached temperature range (48), the collagen bundles assumed different arrangements in the laser group. Significant reductions in the chordae tendineae lengths and changes in their resistance in the laser group were observed, as these chordae exhibited less rigid fibers. The chordae tendineae of normal porcine valves subjected to a high-power laser exhibited its length reduction and less stiffness compared to the control group. A histological analysis of the laser treatment specimens demonstrated differences in collagen bundle spatial organization, following slight changes into tissue temperature.

  18. The role of papillary muscle approximation in mitral valve repair for the treatment of secondary mitral regurgitation.

    PubMed

    Mihos, Christos G; Yucel, Evin; Santana, Orlando

    2016-12-30

    SummarySecondary mitral regurgitation (MR) is present in up to half of patients with dilated cardiomyopathy, and is associated with a poor prognosis. It primarily results from progressive left ventricular remodelling, papillary muscle displacement and tethering of the mitral valve leaflets. Mitral valve repair with an undersized ring annuloplasty is the reparative procedure of choice in the treatment of secondary MR. However, this technique is associated with a 30-60% incidence of recurrent moderate or greater MR at mid-term follow-up, which results in progressive deterioration of left ventricular function and increased morbidity. Combined mitral valve repair and papillary muscle approximation has been applied in order to address both the annular and subvalvular dysfunction that coexist in secondary MR, which include graft and suture-based techniques. Herein, we provide a systematic review of the published literature regarding the technical aspects, clinical application, and outcomes of mitral valve repair with combined ring annuloplasty and papillary muscle approximation for the treatment of secondary MR.

  19. Percutaneous Mitral Valvotomy in a Case of Situs Inversus Totalis and Juvenile Rheumatic Critical Mitral Stenosis: Case Report

    PubMed Central

    Sinha, Santosh Kumar; Thakur, Ramesh; Jha, Mukesh Jitendra; Sayal, Karandeep Singh; Sachan, Mohit; Krishna, Vinay; Kumar, Ashutosh; Mishra, Vikas; Varma, Chandra Mohan

    2016-01-01

    Situs inversus totalis is a rare congenital disorder where the heart being a mirror image is situated on the right side of the body. Distorted cardiac anatomy makes fluoroscopy-guided percutaneous mitral valvotomy (PMV) technically challenging and there are only few reports of PMV in situs inversus totalis. Here we report a case where PMV was successfully done for situs inversus totalis with rare coincidence of juvenile rheumatic severe mitral stenosis in a 12-year-old boy with a few modifications of standard Inoue technique. He had exertional dyspnea of NYHA class III with initial mitral valve area (MVA) of 0.6 cm2 and severe pulmonary arterial hypertension with features suitable for PMV. Femoral vein was accessed from the left side to align the septal puncture needle and balloon to facilitate left ventricular entry. Septal descent and puncture by Brockenbrough needle was performed in the right anterior oblique view with the needle facing 5 o’clock position. Accura balloon was negotiated across mitral valve in left anterior oblique and procedure was successfully executed. Echocardiography showed a well-divided anterior commissure with an MVA of 2.0 cm2 and mild mitral regurgitation. In summary, PMV is safe and feasible in the rare patient with situs inversus totalis with few modifications of the Inoue technique. PMID:26985259

  20. Surgical phantom for off-pump mitral valve replacement

    NASA Astrophysics Data System (ADS)

    McLeod, A. Jonathan; Moore, John; Guiraudon, Gerard M.; Jones, Doug L.; Campbell, Gordon; Peters, Terry M.

    2011-03-01

    Off-pump, intracardiac, beating heart surgery has the potential to improve patient outcomes by eliminating the need for cardiopulmonary bypass and aortic cross clamping but it requires extensive image guidance as well as the development of specialized instrumentation. Previously, developments in image guidance and instrumentation were validated on either a static phantom or in vivo through porcine models. This paper describes the design and development of a surgical phantom for simulating off-pump mitral valve replacement inside the closed beating heart. The phantom allows surgical access to the mitral annulus while mimicking the pressure inside the beating heart. An image guidance system using tracked ultrasound, magnetic instrument tracking and preoperative models previously developed for off-pump mitral valve replacement is applied to the phantom. Pressure measurements and ultrasound images confirm the phantom closely mimics conditions inside the beating heart.

  1. Review of mitral valve insufficiency: repair or replacement

    PubMed Central

    Madesis, Athanasios; Tsakiridis, Kosmas; Katsikogiannis, Nikolaos; Machairiotis, Nikolaos; Kougioumtzi, Ioanna; Kesisis, George; Tsiouda, Theodora; Beleveslis, Thomas; Koletas, Alexander; Zarogoulidis, Konstantinos

    2014-01-01

    Mitral valve (MV) dysfunction is the second-most common clinically significant form of valvular defect in adults. MV regurgitation occurs with the increasing frequency of degenerative changes of the aging process. Moreover, other causes of clinically significant MV regurgitation include cardiac ischemia, infective endocarditis and rhematic disease more frequently in less developed countries. Recent evidence suggests that the best outcomes after repair of severe degenerative mitral regurgitation (MR) are achieved in asymptomatic or minimally symptomatic patients, who are selected for surgery soon after diagnosis on the basis of echocardiography. This review will focus on the surgical management of mitral insufficiency according to its aetiology today and will give insight to some of the perspectives that lay in the future. PMID:24672698

  2. The Ross II procedure: pulmonary autograft in the mitral position.

    PubMed

    Athanasiou, Thanos; Cherian, Ashok; Ross, Donald

    2004-10-01

    The surgical management of mitral valve disease in women of childbearing age, young patients, and children with congenital mitral valve defects is made difficult by the prospect of lifelong anticoagulation. We suggest the use of a pulmonary autograft in the mitral position (Ross II procedure) as an alternative surgical technique. We present a review of the literature, historical perspectives, indications, selection criteria, and surgical technique for the Ross II procedure. Our literature search identified 14 studies that reported results from the Ross II operation. Performed in 103 patients, the overall in-hospital mortality was 7 (6.7%), with a late mortality of 10 (9%). Although further research is needed, current evidence suggests the Ross II operation is a valuable alternative in low-risk young patients where valve durability and the complication rate from other procedures is unsatisfactory and anticoagulation not ideal.

  3. Percutaneous coronary intervention for acute myocardial infarction with mitral regurgitation

    PubMed Central

    Tu, Yan; Zeng, Qing-Chun; Huang, Ying; Li, Jian-Yong

    2016-01-01

    Ischemic mitral regurgitation (IMR) is a common complication of acute myocardial infarction (AMI). Current evidences suggest that revascularization of the culprit vessels with percutaneous coronary artery intervention (PCI) or coronary artery bypass grafting can be beneficial for relieving IMR. A 2.5-year follow-up data of a 61-year-old male patient with ST-segment elevation AMI complicated with IMR showed that mitral regurgitation area increased five days after PCI, and decreased to lower steady level three months after PCI. This finding suggest that three months after PCI might be a suitable time point for evaluating the possibility of IMR recovery and the necessity of surgical intervention of the mitral valve for AMI patient. PMID:27582769

  4. [Longterm results of mitral valve replacement (author's transl)].

    PubMed

    Erhard, W; Reichmann, M; Delius, W; Sebening, H; Herrmann, G

    1977-04-22

    210 patients were followed up by the actuary method for over 5 years after isolated mitral valve replacement or a double valve replacement. After isolated valve replacement the one month survival including the operative mortality was 92+/-2%. The survival after one year was 83+/-3% and after 5 years 66+/-7%. The five year survival of patients in preoperative class III (according to the NYHA) was 73+/-8% and of class IV 57+/-8% (P less than or equal to 0.1). A comparison of valve replacements for pure mitral stenosis or mitral insufficiency showed no statistically significant differences. In the 37 patients who had a double valve replacement the survival risk was not increased in comparison with those patients who had had a single valve replacement. Age above 45 years and a preoperative markedly raised pulmonary arteriolar resistance reduced the chances of survival.

  5. Rethinking Black Hole Accretion Discs

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg

    Accretion discs are staples of astrophysics. Tapping into the gravitational potential energy of the accreting material, these discs are highly efficient machines that produce copious radiation and extreme outflows. While interesting in their own right, accretion discs also act as tools to study black holes and directly influence the properties of the Universe. Black hole X-ray binaries are fantastic natural laboratories for studying accretion disc physics and black hole phenomena. Among many of the curious behaviors exhibited by these systems are black hole state transitions -- complicated cycles of dramatic brightening and dimming. Using X-ray observations with high temporal cadence, we show that the evolution of the accretion disc spectrum during black hole state transitions can be described by a variable disc atmospheric structure without invoking a radially truncated disc geometry. The accretion disc spectrum can be a powerful diagnostic for measuring black hole spin if the effects of the disc atmosphere on the emergent spectrum are well-understood; however, properties of the disc atmosphere are largely unconstrained. Using statistical methods, we decompose this black hole spin measurement technique and show that modest uncertainties regarding the disc atmosphere can lead to erroneous spin measurements. The vertical structure of the disc is difficult to constrain due to our ignorance of the contribution to hydrostatic balance by magnetic fields, which are fundamental to the accretion process. Observations of black hole X-ray binaries and the accretion environments near supermassive black holes provide mounting evidence for strong magnetization. Performing numerical simulations of accretion discs in the shearing box approximation, we impose a net vertical magnetic flux that allows us to effectively control the level of disc magnetization. We study how dynamo activity and the properties of turbulence driven by the magnetorotational instability depend on the

  6. A biomimetic bi-leaflet mitral prosthesis with enhanced physiological left ventricular swirl restorative capability

    NASA Astrophysics Data System (ADS)

    Tan, Sean Guo-Dong; Kim, Sangho; Leo, Hwa Liang

    2016-06-01

    Mechanical heart valve prostheses are often implanted in young patients due to their durability and long-term reliability. However, existing designs are known to induce elevated levels of blood damage and blood platelet activation. As a result, there is a need for patients to undergo chronic anti-coagulation treatment to prevent thrombosis, often resulting in bleeding complications. Furthermore, recent studies have suggested that the implantation of a mechanical prosthetic valve at the mitral position results in a significant alteration of the left ventricular flow field which may contribute to flow turbulence. This study proposes a bi-leaflet mechanical heart valve design (Bio-MHV) that mimics the geometry of a human mitral valve, with the aim of reducing turbulence levels in the left ventricle by replicating physiological flow patterns. An in vitro three-dimensional particle velocimetry imaging experiment was carried out to compare the hemodynamic performance of the Bio-MHV with that of the clinically established ATS valve. The Bio-MHV was found to replicate physiological left ventricular flow patterns and produced lower turbulence levels.

  7. Prolonged Intracellular Na+ Dynamics Govern Electrical Activity in Accessory Olfactory Bulb Mitral Cells

    PubMed Central

    Zylbertal, Asaph; Kahan, Anat; Ben-Shaul, Yoram; Yarom, Yosef; Wagner, Shlomo

    2015-01-01

    Persistent activity has been reported in many brain areas and is hypothesized to mediate working memory and emotional brain states and to rely upon network or biophysical feedback. Here, we demonstrate a novel mechanism by which persistent neuronal activity can be generated without feedback, relying instead on the slow removal of Na+ from neurons following bursts of activity. We show that mitral cells in the accessory olfactory bulb (AOB), which plays a major role in mammalian social behavior, may respond to a brief sensory stimulation with persistent firing. By combining electrical recordings, Ca2+ and Na+ imaging, and realistic computational modeling, we explored the mechanisms underlying the persistent activity in AOB mitral cells. We found that the exceptionally slow inward current that underlies this activity is governed by prolonged dynamics of intracellular Na+ ([Na+]i), which affects neuronal electrical activity via several pathways. Specifically, elevated dendritic [Na+]i reverses the Na+-Ca2+ exchanger activity, thus modifying the [Ca2+]i set-point. This process, which relies on ubiquitous membrane mechanisms, is likely to play a role in other neuronal types in various brain regions. PMID:26674618

  8. Evolution of gas in debris discs

    NASA Astrophysics Data System (ADS)

    Kral, Quentin; Wyatt, Mark; Pringle, Jim

    2015-12-01

    A non negligible quantity of gas has been discovered in an increasing number of debris disc systems. ALMA high sensitivity and high resolution is changing our perception of the gaseous component of debris discs as CO is discovered in systems where it should be rapidly photodissociated. It implies that there is a replenishment mechanism and that the observed gas is secondary. Past missions such as Herschel probed the atomic part of the gas through O I and C II emission lines. Gas science in debris discs is still in its infancy, and these new observations raise a handful of questions concerning the mechanisms to create the gas and about its evolution in the planetary system when it is released. The latter question will be addressed in this talk as a self-consistent gas evolution scenario is proposed and is compared to observations for the peculiar case of β Pictoris.Our model proposes that carbon and oxygen within debris discs are created due to photodissociation of CO which is itself created from the debris disc dust (due to grain-grain collisions or photodesorption). The evolution of the carbon atoms is modelled as viscous spreading, with viscosity parameterised using an α model. The temperature, ionisation fraction and population levels of carbon are followed with a PDR model called Cloudy, which is coupled to the dynamical viscous α model. Only carbon gets ionised due to its lower ionisation potential than oxygen. The carbon gas disc can end up with a high ionisation fraction due to strong FUV radiation field. A high ionisation fraction means that the magnetorotational instability (MRI) is very active, so that α is very high. Gas density profiles can be worked out for different input parameters such as the α value, the CO input rate, the location of the input and the incoming radiation field. Observability predictions can be made for future observations, and our model is tested on β Pictoris observations. This new gas evolution model fits the carbon and CO

  9. Heat distribution in disc brake

    NASA Astrophysics Data System (ADS)

    Klimenda, Frantisek; Soukup, Josef; Kampo, Jan

    2016-06-01

    This article is deals by the thermal analysis of the disc brake with floating caliper. The issue is solved by numerically. The half 2D model is used for solution in program ADINA 8.8. Two brake discs without the ventilation are solved. One disc is made from cast iron and the second is made from stainless steel. Both materials are an isotropic. By acting the pressure force on the brake pads will be pressing the pads to the brake disc. Speed will be reduced (slowing down). On the contact surface generates the heat, which the disc and pads heats. In the next part of article is comparison the maximum temperature at the time of braking. The temperatures of both materials for brake disc (gray cast iron, stainless steel) are compares. The heat flux during braking for the both materials is shown.

  10. Enclosed rotary disc air pulser

    DOEpatents

    Olson, A. L.; Batcheller, Tom A.; Rindfleisch, J. A.; Morgan, John M.

    1989-01-01

    An enclosed rotary disc air pulser for use with a solvent extraction pulse olumn includes a housing having inlet, exhaust and pulse leg ports, a shaft mounted in the housing and adapted for axial rotation therein, first and second disc members secured to the shaft within the housing in spaced relation to each other to define a chamber therebetween, the chamber being in communication with the pulse leg port, the first disc member located adjacent the inlet port, the second disc member being located adjacent the exhaust port, each disc member having a milled out portion, the disc members positioned on the shaft so that as the shaft rotates, the milled out portions permit alternative cyclical communication between the inlet port and the chamber and the exhaust port and the chamber.

  11. Septic Cerebral Embolisation in Fulminant Mitral Valve Infective Endocarditis

    PubMed Central

    Doolub, Gemina

    2015-01-01

    A 37-year-old male with known intravenous drug use was admitted with an acute onset of worsening confusion and speech impairment. His vitals and biochemical profile demonstrated severe sepsis, with a brain CT showing several lesions suspicious for cerebral emboli. He then went on to have a bedside transthoracic echocardiogram that was positive for vegetation on the mitral valve, with associated severe mitral regurgitation. Unfortunately, before he was stable enough to be transferred for valve surgery, he suffered an episode of acute pulmonary oedema requiring intubation and ventilation on intensive care unit. PMID:26120312

  12. The use of three-dimensional echocardiography for the evaluation of and treatment of mitral stenosis.

    PubMed

    de Agustin, Jose A; Nanda, Navin C; Gill, Edward A; de Isla, Leopoldo Pérez; Zamorano, Jose L

    2007-05-01

    To date, mitral stenosis has been evaluated by both hemodynamic data derived from catheterization as well as 2D and Doppler echocardiography. However, the advent of real-time 3D echocardiography has allowed more precise measurement of the mitral valve orifice by planimetry. In addition, evaluation of the mitral commissures prior to and after percutaneous mitral valvuloplasty is greatly aided by 3D echocardiography. Here we discuss these subjects as well as provide specific clinical trials that support the use of real-time 3D echocardiography for the evaluation and treatment of mitral stenosis.

  13. A quantitative approach to the intraoperative echocardiographic assessment of the mitral valve for repair.

    PubMed

    Mahmood, Feroze; Matyal, Robina

    2015-07-01

    Intraoperative echocardiography of the mitral valve has evolved from a qualitative assessment of flow-dependent variables to quantitative geometric analyses before and after repair. In addition, 3-dimensional echocardiographic data now allow for a precise assessment of mitral valve apparatus. Complex structures, such as the mitral annulus, can be interrogated comprehensively without geometric assumptions. Quantitative analyses of mitral valve apparatus are particularly valuable for identifying indices of left ventricular and mitral remodeling to establish the chronicity and severity of mitral regurgitation. This can help identify patients who may be unsuitable candidates for repair as the result of irreversible remodeling of the mitral valve apparatus. Principles of geometric analyses also have been extended to the assessment of repaired mitral valves. Changes in mitral annular shape and size determine the stress exerted on the mitral leaflets and, therefore, the durability of repair. Given this context, echocardiographers may be expected to diagnose and quantify valvular dysfunction, assess suitability for repair, assist in annuloplasty ring sizing, and determine the success and failure of the repair procedure. As a result, anesthesiologists have progressed from being mere service providers to participants in the decision-making process. It is therefore prudent for them to acquaint themselves with the principles of intraoperative quantitative mitral valve analysis to assist in rational and objective decision making.

  14. In vitro and in silico investigations of disc nucleus replacement.

    PubMed

    Reitmaier, Sandra; Shirazi-Adl, Aboulfazl; Bashkuev, Maxim; Wilke, Hans-Joachim; Gloria, Antonio; Schmidt, Hendrik

    2012-08-07

    Currently, numerous hydrogels are under examination as potential nucleus replacements. The clinical success, however, depends on how well the mechanical function of the host structure is restored. This study aimed to evaluate the extent to and mechanisms by which surgery for nucleus replacements influence the mechanical behaviour of the disc. The effects of an annulus defect with and without nucleus replacement on disc height and nucleus pressure were measured using 24 ovine motion segments. The following cases were considered: intact; annulus incision repaired by suture and glue; annulus incision with removal and re-implantation of nucleus tissue repaired by suture and glue or plug. To identify the likely mechanisms observed in vitro, a finite-element model of a human disc (L4-L5) was employed. Both studies were subjected to physiological cycles of compression and recovery. A repaired annulus defect did not influence the disc behaviour in vitro, whereas additional nucleus removal and replacement substantially decreased disc stiffness and nucleus pressure. Model predictions demonstrated the substantial effects of reductions in replaced nucleus water content, bulk modulus and osmotic potential on disc height loss and pressure, similar to measurements. In these events, the compression load transfer in the disc markedly altered by substantially increasing the load on the annulus when compared with the nucleus. The success of hydrogels for nucleus replacements is not only dependent on the implant material itself but also on the restoration of the environment perturbed during surgery. The substantial effects on the disc response of disruptions owing to nucleus replacements can be simulated by reduced nucleus water content, elastic modulus and osmotic potential.

  15. In vitro and in silico investigations of disc nucleus replacement

    PubMed Central

    Reitmaier, Sandra; Shirazi-Adl, Aboulfazl; Bashkuev, Maxim; Wilke, Hans-Joachim; Gloria, Antonio; Schmidt, Hendrik

    2012-01-01

    Currently, numerous hydrogels are under examination as potential nucleus replacements. The clinical success, however, depends on how well the mechanical function of the host structure is restored. This study aimed to evaluate the extent to and mechanisms by which surgery for nucleus replacements influence the mechanical behaviour of the disc. The effects of an annulus defect with and without nucleus replacement on disc height and nucleus pressure were measured using 24 ovine motion segments. The following cases were considered: intact; annulus incision repaired by suture and glue; annulus incision with removal and re-implantation of nucleus tissue repaired by suture and glue or plug. To identify the likely mechanisms observed in vitro, a finite-element model of a human disc (L4–L5) was employed. Both studies were subjected to physiological cycles of compression and recovery. A repaired annulus defect did not influence the disc behaviour in vitro, whereas additional nucleus removal and replacement substantially decreased disc stiffness and nucleus pressure. Model predictions demonstrated the substantial effects of reductions in replaced nucleus water content, bulk modulus and osmotic potential on disc height loss and pressure, similar to measurements. In these events, the compression load transfer in the disc markedly altered by substantially increasing the load on the annulus when compared with the nucleus. The success of hydrogels for nucleus replacements is not only dependent on the implant material itself but also on the restoration of the environment perturbed during surgery. The substantial effects on the disc response of disruptions owing to nucleus replacements can be simulated by reduced nucleus water content, elastic modulus and osmotic potential. PMID:22337630

  16. How safe is it to train residents to perform mitral valve surgery?

    PubMed

    Gabriel, Joseph; Göbölös, László; Miskolczi, Szabolcs; Barlow, Clifford

    2016-11-01

    A best evidence topic was constructed according to a structured protocol. The enquiry: In [patients undergoing mitral valve surgery] are [postoperative morbidity and mortality outcomes] acceptable when patients are operated on by [residents]? Four hundred and twenty-three were identified from the search strategy. Six articles selected as best evidence were tabulated. All current published evidence, encompassing open and minimally invasive mitral valve repair in addition to mitral valve replacement, supports the involvement of trainees in mitral procedures. Although trainees may experience longer aortic cross-clamp and cardiopulmonary bypass times than specialist surgeons, they are not associated with significantly worse perioperative or postoperative outcomes in comparable mitral procedures. Important factors in the viability of mitral valve training and its quality include the volume of cases per institution and the expertise of the supervising surgeon, and these remain largely unexplored. Overall, mitral valve surgery remains a valuable potential training opportunity, one which is perhaps underexploited.

  17. Preparation of ormetoprim sulfadimethoxine medicated discs for disc diffusion assay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Romet (a blend of ormetoprim and sulfadimethoxine) is a typeA medicated article for the manufacture of medicated feed in the catfish industry. Recently, the commercial manufacture of ormetoprim–sulfadimethoxine susceptibility discs was discontinued. Ormetoprim–sulfadimethoxine discs were prepared at...

  18. Sizes of protoplanetary discs after star-disc encounters

    NASA Astrophysics Data System (ADS)

    Breslau, Andreas; Steinhausen, Manuel; Vincke, Kirsten; Pfalzner, Susanne

    2014-05-01

    Most stars do not form in isolation, but as part of a star cluster or association. These young stars are initially surrounded by protoplanetary discs. In these cluster environments tidal interactions with other cluster members can alter the disc properties. Besides the disc frequency, its mass, angular momentum, and energy, the disc's size is particularly prone to being changed by a passing star. So far the change in disc size has only been investigated for a small number of very specific encounters. Several studies investigated the effect of the cluster environment on the sizes of planetary systems like our own solar system, based on a generalisation of information from this limited sample. We performed numerical simulations covering the wide parameter space typical of young star clusters, to test the validity of this approach. Here the sizes of discs after encounters are presented, based on a size definition that is comparable to the one used in observational studies. We find that, except for encounters between equal-mass stars, the usually applied estimates are insufficient. They tend to severely overestimate the remaining disc size. We show that the disc size after an encounter can be described by a relatively simple dependence on the periastron distance and the mass ratio of the encounter partners. This knowledge allows us, for example, to pin down the types of encounter possibly responsible for the structure of today's solar system. Appendix A is available in electronic form at http://www.aanda.org

  19. ROS: Crucial Intermediators in the Pathogenesis of Intervertebral Disc Degeneration

    PubMed Central

    Yang, Minghui; Lan, Minghong; Liu, Chang; Zhang, Yang; Huang, Bo

    2017-01-01

    Excessive reactive oxygen species (ROS) generation in degenerative intervertebral disc (IVD) indicates the contribution of oxidative stress to IVD degeneration (IDD), giving a novel insight into the pathogenesis of IDD. ROS are crucial intermediators in the signaling network of disc cells. They regulate the matrix metabolism, proinflammatory phenotype, apoptosis, autophagy, and senescence of disc cells. Oxidative stress not only reinforces matrix degradation and inflammation, but also promotes the decrease in the number of viable and functional cells in the microenvironment of IVDs. Moreover, ROS modify matrix proteins in IVDs to cause oxidative damage of disc extracellular matrix, impairing the mechanical function of IVDs. Consequently, the progression of IDD is accelerated. Therefore, a therapeutic strategy targeting oxidative stress would provide a novel perspective for IDD treatment. Various antioxidants have been proposed as effective drugs for IDD treatment. Antioxidant supplementation suppresses ROS production in disc cells to promote the matrix synthesis of disc cells and to prevent disc cells from death and senescence in vitro. However, there is not enough in vivo evidence to support the efficiency of antioxidant supplementation to retard the process of IDD. Further investigations based on in vivo and clinical studies will be required to develop effective antioxidative therapies for IDD. PMID:28392887

  20. Respiration Gates Sensory Input Responses in the Mitral Cell Layer of the Olfactory Bulb

    PubMed Central

    Short, Shaina M.; Morse, Thomas M.; McTavish, Thomas S.; Shepherd, Gordon M.; Verhagen, Justus V.

    2016-01-01

    Respiration plays an essential role in odor processing. Even in the absence of odors, oscillating excitatory and inhibitory activity in the olfactory bulb synchronizes with respiration, commonly resulting in a burst of action potentials in mammalian mitral/tufted cells (MTCs) during the transition from inhalation to exhalation. This excitation is followed by inhibition that quiets MTC activity in both the glomerular and granule cell layers. Odor processing is hypothesized to be modulated by and may even rely on respiration-mediated activity, yet exactly how respiration influences sensory processing by MTCs is still not well understood. By using optogenetics to stimulate discrete sensory inputs in vivo, it was possible to temporally vary the stimulus to occur at unique phases of each respiration. Single unit recordings obtained from the mitral cell layer were used to map spatiotemporal patterns of glomerular evoked responses that were unique to stimulations occurring during periods of inhalation or exhalation. Sensory evoked activity in MTCs was gated to periods outside phasic respiratory mediated firing, causing net shifts in MTC activity across the cycle. In contrast, odor evoked inhibitory responses appear to be permitted throughout the respiratory cycle. Computational models were used to further explore mechanisms of inhibition that can be activated by respiratory activity and influence MTC responses. In silico results indicate that both periglomerular and granule cell inhibition can be activated by respiration to internally gate sensory responses in the olfactory bulb. Both the respiration rate and strength of lateral connectivity influenced inhibitory mechanisms that gate sensory evoked responses. PMID:28005923

  1. Braking down an accreting protostar: disc-locking, disc winds, stellar winds, X-winds and Magnetospheric Ejecta

    NASA Astrophysics Data System (ADS)

    Ferreira, J.

    2013-09-01

    Classical T Tauri stars are low mass young forming stars that are surrounded by a circumstellar accretion disc from which they gain mass. Despite this accretion and their own contraction that should both lead to their spin up, these stars seem to conserve instead an almost constant rotational period as long as the disc is maintained. Several scenarios have been proposed in the literature in order to explain this puzzling "disc-locking" situation: either deposition in the disc of the stellar angular momentum by the stellar magnetosphere or its ejection through winds, providing thereby an explanation of jets from Young Stellar Objects. In this lecture, these various mechanisms will be critically detailed, from the physics of the star-disc interaction to the launching of self-confined jets (disc winds, stellar winds, X-winds, conical winds). It will be shown that no simple model can account alone for the whole bulk of observational data and that "disc locking" requires a combination of some of them.

  2. Takotsubo syndrome after mitral valve replacement for acute endocarditis.

    PubMed

    Gariboldi, Vlad; Jop, Bertrand; Grisoli, Dominique; Jaussaud, Nicolas; Kerbaul, François; Collart, Frédéric

    2011-03-01

    Takotsubo syndrome is characterized by transient and acute left ventricular dysfunction and apical ballooning, with electrocardiographic abnormalities, but without coronary disease. We report a case of Takotsubo syndrome occurring after emergent mitral valve replacement for acute infective endocarditis. The patient is a 66-year-old woman who regained complete recovery of left ventricular function.

  3. Evaluation of mitral valve replacement anchoring in a phantom

    NASA Astrophysics Data System (ADS)

    McLeod, A. Jonathan; Moore, John; Lang, Pencilla; Bainbridge, Dan; Campbell, Gordon; Jones, Doug L.; Guiraudon, Gerard M.; Peters, Terry M.

    2012-02-01

    Conventional mitral valve replacement requires a median sternotomy and cardio-pulmonary bypass with aortic crossclamping and is associated with significant mortality and morbidity which could be reduced by performing the procedure off-pump. Replacing the mitral valve in the closed, off-pump, beating heart requires extensive development and validation of surgical and imaging techniques. Image guidance systems and surgical access for off-pump mitral valve replacement have been previously developed, allowing the prosthetic valve to be safely introduced into the left atrium and inserted into the mitral annulus. The major remaining challenge is to design a method of securely anchoring the prosthetic valve inside the beating heart. The development of anchoring techniques has been hampered by the expense and difficulty in conducting large animal studies. In this paper, we demonstrate how prosthetic valve anchoring may be evaluated in a dynamic phantom. The phantom provides a consistent testing environment where pressure measurements and Doppler ultrasound can be used to monitor and assess the valve anchoring procedures, detecting pararvalvular leak when valve anchoring is inadequate. Minimally invasive anchoring techniques may be directly compared to the current gold standard of valves sutured under direct vision, providing a useful tool for the validation of new surgical instruments.

  4. Experimental model of intervertebral disc degeneration by needle puncture in Wistar rats

    PubMed Central

    Issy, A.C.; Castania, V.; Castania, M.; Salmon, C.E.G.; Nogueira-Barbosa, M.H.; Bel, E. Del; Defino, H.L.A.

    2013-01-01

    Animal models of intervertebral disc degeneration play an important role in clarifying the physiopathological mechanisms and testing novel therapeutic strategies. The objective of the present study is to describe a simple animal model of disc degeneration involving Wistar rats to be used for research studies. Disc degeneration was confirmed and classified by radiography, magnetic resonance and histological evaluation. Adult male Wistar rats were anesthetized and submitted to percutaneous disc puncture with a 20-gauge needle on levels 6-7 and 8-9 of the coccygeal vertebrae. The needle was inserted into the discs guided by fluoroscopy and its tip was positioned crossing the nucleus pulposus up to the contralateral annulus fibrosus, rotated 360° twice, and held for 30 s. To grade the severity of intervertebral disc degeneration, we measured the intervertebral disc height from radiographic images 7 and 30 days after the injury, and the signal intensity T2-weighted magnetic resonance imaging. Histological analysis was performed with hematoxylin-eosin and collagen fiber orientation using picrosirius red staining and polarized light microscopy. Imaging and histological score analyses revealed significant disc degeneration both 7 and 30 days after the lesion, without deaths or systemic complications. Interobserver histological evaluation showed significant agreement. There was a significant positive correlation between histological score and intervertebral disc height 7 and 30 days after the lesion. We conclude that the tail disc puncture method using Wistar rats is a simple, cost-effective and reproducible model for inducing disc degeneration. PMID:23532265

  5. Novel localized heating technique on centrifugal microfluidic disc with wireless temperature monitoring system.

    PubMed

    Joseph, Karunan; Ibrahim, Fatimah; Cho, Jongman

    2015-01-01

    Recent advances in the field of centrifugal microfluidic disc suggest the need for electrical interface in the disc to perform active biomedical assays. In this paper, we have demonstrated an active application powered by the energy harvested from the rotation of the centrifugal microfluidic disc. A novel integration of power harvester disc onto centrifugal microfluidic disc to perform localized heating technique is the main idea of our paper. The power harvester disc utilizing electromagnetic induction mechanism generates electrical energy from the rotation of the disc. This contributes to the heat generation by the embedded heater on the localized heating disc. The main characteristic observed in our experiment is the heating pattern in relative to the rotation of the disc. The heating pattern is monitored wirelessly with a digital temperature sensing system also embedded on the disc. Maximum temperature achieved is 82 °C at rotational speed of 2000 RPM. The technique proves to be effective for continuous heating without the need to stop the centrifugal motion of the disc.

  6. Intraoral micro-identification discs.

    PubMed

    Hansen, R W

    1991-12-01

    Intraoral micro-identification discs have recently been utilized to provide a more permanent method of personal identification. A wafer of plastic or metal with a surface area of 2.5 to 5 mm2 and carrying identifying numbers and/or letters (indicia) is bonded to the buccal enamel surface of the posterior teeth. Personal identification can occur after the I.D. disc is identified and the indicia is read. Reading of photoreduced indicia requires the aid of a microscope subsequent to the removal of the microdisc. In situ reading of disc indicia is possible using low power handheld magnifiers if the size of the indicia approximates 0.3 mm. Computerization is an integral part of non-custom alpha/numeric type designs, but a custom disc carries a name, address, and other specific information unique to the manufacturer. The use of a computer improves access to the database and it decreases the amount of data placed on the disc. Microdisc bases may be fabricated using a mylar type plastic or they may be manufactured from a stainless steel blank. Plastic discs are constructed with an internal sandwich containing the photo-reduced indicia. Metal discs are marked with a photochemical etch or engraved with a computer driven YAG laser. Attachment of the disc to the enamel surface is accomplished by conventional etching and bonding techniques and are typically bonded to the buccal surface of the maxillary first permanent molar or the second primary molar. Clear composite bonding material covers the disc so that salivary contamination does not result in degradation of the indicia. Orthodontic style discs with a mesh back carry laser written information that may be cemented with conventional orthodontic bonding cement. Standardization of the indicia and overall design is considered to be an important aspect of patient and professional acceptance.

  7. Alignment in star-debris disc systems seen by Herschel

    NASA Astrophysics Data System (ADS)

    Greaves, J. S.; Kennedy, G. M.; Thureau, N.; Eiroa, C.; Marshall, J. P.; Maldonado, J.; Matthews, B. C.; Olofsson, G.; Barlow, M. J.; Moro-Martín, A.; Sibthorpe, B.; Absil, O.; Ardila, D. R.; Booth, M.; Broekhoven-Fiene, H.; Brown, D. J. A.; Cameron, A. Collier; del Burgo, C.; Di Francesco, J.; Eislöffel, J.; Duchêne, G.; Ertel, S.; Holland, W. S.; Horner, J.; Kalas, P.; Kavelaars, J. J.; Lestrade, J.-F.; Vican, L.; Wilner, D. J.; Wolf, S.; Wyatt, M. C.

    2014-02-01

    Many nearby main-sequence stars have been searched for debris using the far-infrared Herschel satellite, within the DEBRIS, DUNES and Guaranteed-Time Key Projects. We discuss here 11 stars of spectral types A-M where the stellar inclination is known and can be compared to that of the spatially resolved dust belts. The discs are found to be well aligned with the stellar equators, as in the case of the Sun's Kuiper belt, and unlike many close-in planets seen in transit surveys. The ensemble of stars here can be fitted with a star-disc tilt of ≲ 10°. These results suggest that proposed mechanisms for tilting the star or disc in fact operate rarely. A few systems also host imaged planets, whose orbits at tens of au are aligned with the debris discs, contrary to what might be expected in models where external perturbers induce tilts.

  8. Lumbar Disc Herniation Presented with Contralateral Symptoms

    PubMed Central

    Kim, Pius; Ju, Chang Il; Kim, Hyeun Sung; Kim, Seok Won

    2017-01-01

    Objective This study aimed to unravel the putative mechanism underlying the neurologic deficits contralateral to the side with lumbar disc herniation (LDH) and to elucidate the treatment for this condition. Methods From January 2009 to June 2015, 8 patients with LDH with predominantly contralateral neurologic deficits underwent surgical treatment on the side with LDH with or without decompressing the symptomatic side. A retrospective review of charts and radiological records of these 8 patients was performed. The putative mechanisms underlying the associated contralateral neurological deficits, magnetic resonance imaging (MRI), electromyography (EMG), and the adequate surgical approach are discussed here. Results MRI revealed a similar laterally skewed paramedian disc herniation, with the apex deviated from the symptomatic side rather than directly compressing the nerve root; this condition may generate a contralateral traction force. EMG revealed radiculopathies in both sides of 6 patients and in the herniated side of 2 patients. Based on EMG findings and the existence of suspicious lateral recess stenosis of the symptomatic side, 6 patients underwent bilateral decompression of nerve roots and 2 were subjected to a microscopic discectomy to treat the asymptomatic disc herniation. No specific conditions such as venous congestion, nerve root anomaly or epidural lipomatosis were observed, which may be considered the putative pathomechanism causing the contralateral neurological deficits. The symptoms resolved significantly after surgery. Conclusion The traction force generated on the contralateral side and lateral recess stenosis, rather than direct compression, may cause the contralateral neurologic deficits observed in LDH. PMID:28264243

  9. Immediate and long-term results of mitral valve replacement with University of Cape Town mitral valve prosthesis

    PubMed Central

    Schrire, Velva; Barnard, Christiaan N.

    1970-01-01

    We describe seven years' experience with the University of Cape Town lenticular mitral valve prosthesis in 122 patients. All the patients had severe mitral valve disease. In 98 severe mitral stenosis was present with or without incompetence and in 24 the dominant or sole lesion was mitral incompetence. Other valves, particularly the tricuspid, were also frequently affected. The disability was severe or total in almost every patient. One hundred and five patients were discharged from hospital, and in 90 per cent of these the clinical improvement was most gratifying, with the disappearance of pulmonary oedema, paroxysmal dyspnoea, angina pectoris, and congestive cardiac failure. Return to full normal activity including physical work was the rule. The hospital mortality was 14 per cent and a further 38 per cent died during the follow-up period. The major post-operative complication was systemic embolism which could occur at any time after operation. The most important factor influencing the frequency of this complication was the nature of the valve seat. A bare steel seat was associated with a 100 per cent embolism, and a significant reduction occurred when a cloth-covered seat of Dacron-velour was introduced. Anticoagulant therapy appeared to prevent large or fresh clots but had no effect on the deposition of fibrin or platelet thrombi. The only other factor of importance was the age of the patient: after the age of 50 life expectancy and trouble-free long-term survival was reduced. Images PMID:5440520

  10. Hall magneto-hydrodynamics in protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Béthune, W.; Lesur, G.; Ferreira, J.

    2016-12-01

    Protoplanetary discs exhibit large-scale, organised structures. Because they are dense and cold, they should be weakly ionized, and hence concerned by non-ideal plasma effects, such as the Hall effect. We perform numerical simulations of non-stratified Keplerian discs, in the non-ideal magnetohydrodynamic framework. We show that the Hall effect causes self-organisation through three distinct stages. A weak Hall effect enhances turbulent transport. At intermediate strength, it produces magnetized vortices. A strong Hall effect generates axisymmetric zonal flows. These structures may trap dust particles, and thus influence planetary formation. The transport of angular momentum is quenched in the organised state, impugning the relevance of magneto-rotational turbulence as a driving mechanism of accretion in Hall dominated regions.

  11. Radio Monitoring of Protoplanetary Discs

    NASA Astrophysics Data System (ADS)

    Ubach, C.; Maddison, S. T.; Wright, C. M.; Wilner, D. J.; Lommen, D. J. P.; Koribalski, B.

    2017-01-01

    Protoplanetary disc systems observed at radio wavelengths often show excess emission above that expected from a simple extrapolation of thermal dust emission observed at short millimetre wavelengths. Monitoring the emission at radio wavelengths can be used to help disentangle the physical mechanisms responsible for this excess, including free-free emission from a wind or jet, and chromospheric emission associated with stellar activity. We present new results from a radio monitoring survey conducted with Australia Telescope Compact Array over the course of several years with observation intervals spanning days, months and years, where the flux variability of 11 T Tauri stars in the Chamaeleon and Lupus star forming regions was measured at 7 and 15 mm and 3 and 6 cm. Results show that for most sources are variable to some degree at 7 mm, indicating the presence of emission mechanisms other than thermal dust in some sources. Additionally, evidence of grain growth to cm-sized pebbles was found for some sources that also have signs of variable flux at 7 mm. We conclude that multiple processes contributing to the emission are common in T Tauri stars at 7 mm and beyond, and that a detection at a single epoch at radio wavelengths should not be used to determine all processes contributing to the emission.

  12. Is an adjunctive subvalvular repair during mitral annuloplasty for secondary mitral regurgitation effective in preventing recurrent regurgitation?

    PubMed

    Mihos, Christos G; Santana, Orlando

    2016-02-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: Is an adjunctive subvalvular repair during mitral annuloplasty for secondary mitral regurgitation effective in preventing recurrent regurgitation? Altogether, 353 studies were found using the reported search, of which 9 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. The best evidence regarding adjunctive subvalvular repair during mitral annuloplasty for secondary mitral regurgitation was from retrospective analyses. The studies reported outcomes of mitral valve repair (MVr) with annuloplasty alone (ring MVr) versus adjunctive papillary muscle approximation (PMA; n = 3), papillary muscle relocation (PMR; n = 3), secondary chordal cutting (n = 2) and PMA + PMR (n = 1). All but one study included concomitant coronary artery bypass grafting, whereas additional ventriculoplasty was performed in three studies. Follow-up ranged from 1 month to 5 years. The performance of PMA was associated with a lower mitral regurgitation (MR) grade when combined with ventriculoplasty in one study, whereas a greater improvement in left ventricular end-diastolic diameter and left ventricular ejection fraction at follow-up was observed with PMA alone in a separate study. Three studies of ring + PMR reported a reduction in ≥ 2+ recurrent MR, whereas two studies also observed a greater reduction in left ventricular end-diastolic diameter. The two studies on secondary chordal cutting reported a lower MR grade, lower recurrence of ≥ 2+ MR and a greater left ventricular ejection fraction at follow-up. Combining PMA + PMR + ventriculoplasty significantly reduced left ventricular end-systolic volume index at short-term follow-up in one study. Finally, none of the studies reported a significant difference in

  13. Late outcome of patients with Braunwald-Cutter mitral valve replacement.

    PubMed

    Abdulali, S A; Silverton, N P; Schoen, F J; Saunders, N R; Ionescu, M I

    1984-12-01

    Eighty patients who underwent mitral valve replacement (MVR) with Braunwald-Cutter prostheses (54, single valve replacement; 26, multiple valve replacement) between December, 1972, and September, 1975, are discussed. The period of follow-up ranged from 72 to 120 months with a mean of 84.6 months. For the hospital survivors, actuarial survival at ten years was 73 +/- 6.7% for patients with MVR alone and 30 +/- 17.5% for those with multiple valve replacement. The linearized rate of embolic complications in patients with MVR was 3.2% per year and in patients with multiple valve replacement, 1.5% per year. These low rates of embolism allow a favorable comparison of the Braunwald-Cutter valve with other mechanical prostheses. There was no evidence of serious poppet wear or poppet escape after ten years of the valve in the mitral and tricuspid positions. Thus, elective replacement of the Braunwald-Cutter valve from the atrioventricular position because of this potential problem is not considered necessary. In the aortic position, escape of the poppet from the valve has occurred as late as 101 months. The overall morbidity for the group was high. Only 34% of the patients having MVR and 12% of those with multiple valve replacement are expected to be alive and to remain free from any major complication ten years after operation.

  14. Mitral Valve Regurgitation in the LVAD-Assisted Heart Studied in a Mock Circulatory Loop.

    PubMed

    May-Newman, K; Fisher, B; Hara, M; Dembitsky, W; Adamson, R

    2016-06-01

    Permanent closure of the aortic valve (AVC) is sometimes performed In LVAD patients, usually when a mechanical valve prosthesis or significant aortic insufficiency is present. Mitral valve regurgitation (MVR) present at the time of LVAD implantation can remain unresolved, representing a limitation for exercise tolerance and a potential predictor of mortality. To investigate the effect of MVR on hemodynamics of the LVAD-supported heart following AVC, studies were performed using a mock circulatory loop. Pressure and flow measured for a range of cardiac function, LVAD speed, and MVR show that cardiac contraction augments aortic pressure by 10-27% over nonpulsatile conditions when the mitral valve functions normally, but decreases with MVR until it reaches the nonpulsatile level. Aortic flow displays a similar trend, demonstrating a 25% decrease from fully functioning to open at 7 krpm, a 5% decrease at 9 krpm, and no observable effect at 11 krpm. Pulsatility decreases with increased LVAD speed and MVR. The data indicate that a modest level of cardiac output (1.5-2 L/min) can be maintained by the native heart through the LVAD when the LVAD is off. These results demonstrate that MVR decreases the augmentation of forward flow by improved cardiac function at lower LVAD speeds. While some level of MVR can be tolerated in LVAD recipients, this condition represents a risk, particularly in those patients that undergo AVC closure, and may warrant repair at the time of surgery.

  15. [The thickness/radius ratio (h/r) of the left ventricle in pure mitral insufficiency].

    PubMed

    Guadalajara, J F; Alexánderson, E; Monobe, F; Nieto, S; Huerta, D

    1992-01-01

    We studied 11 patients with severe mitral regurgitation (MR). With 2-D echocardiogram we could obtain the septal and posterior wall thickness, left ventricular internal dimensions and ventricular function. With parasternal short axis view we calculate the h/r ratio (left ventricular thickness/radius). The results were compared with normal values: we found important left atrial and ventricle dilatation with significative difference from the normal values (P < 0.001), the diastolic and systolic h/r ratio was significative lower than the normal values (P < 0.005): the systolic wall stress was significative higher in relation to normal values (P < 0.001). We conclude that patients with severe (MR) initially have an important ventricular dilatation but no hypertrophy despite volume overload. The possible explanation is that in early stages of the disease, the afterload of the left ventricle is low and does not trigger the development of hypertrophy. The hypertrophy appears only when the systolic stress is high secondary to myocardial failure. The excessive dilatation of the left ventricle probably damages the myocardial fibers by excessive stretch. This mechanism probably explains the poor late surgical evolution of patients with mitral prosthesis. This we propose that the optimal surgical timing for such patients is when the systolic wall stress elevates over the normal limits, because this is an early sign of myocardial failure.

  16. Cervical Total Disc Arthroplasty

    PubMed Central

    Basho, Rahul; Hood, Kenneth A.

    2012-01-01

    Symptomatic adjacent segment degeneration of the cervical spine remains problematic for patients and surgeons alike. Despite advances in surgical techniques and instrumentation, the solution remains elusive. Spurred by the success of total joint arthroplasty in hips and knees, surgeons and industry have turned to motion preservation devices in the cervical spine. By preserving motion at the diseased level, the hope is that adjacent segment degeneration can be prevented. Multiple cervical disc arthroplasty devices have come onto the market and completed Food and Drug Administration Investigational Device Exemption trials. Though some of the early results demonstrate equivalency of arthroplasty to fusion, compelling evidence of benefits in terms of symptomatic adjacent segment degeneration are lacking. In addition, non-industry-sponsored studies indicate that these devices are equivalent to fusion in terms of adjacent segment degeneration. Longer-term studies will eventually provide the definitive answer. PMID:24353955

  17. A pig model of ischemic mitral regurgitation induced by mitral chordae tendinae rupture and implantation of an ameroid constrictor.

    PubMed

    Cui, Yong-Chun; Li, Kai; Tian, Yi; Yuan, Wei-Min; Peng, Peng; Yang, Jian-Zhong; Zhang, Bao-Jie; Zhang, Hui-Dong; Wu, Ai-Li; Tang, Yue

    2014-01-01

    A miniature pig model of ischemic mitral regurgitation (IMR) was developed by posterior mitral chordae tendinae rupture and implantation of an ameroid constrictor. A 2.5-mm ameroid constrictor was placed around the left circumflex coronary artery (LCX) of male Tibetan miniature pigs to induce ischemia, while the posterior mitral chordae tendinae was also ruptured. X-ray coronary angiography, ECG analysis, echocardiography, and magnetic resonance imaging (MRI) were used to evaluate heart structure and function in pigs at baseline and one, two, four and eight weeks after the operation. Blood velocity of the mitral regurgitation was found to be between medium and high levels. Angiographic analyses revealed that the LCX closure was 10-20% at one week, 30-40% at two weeks and 90-100% at four weeks subsequent ameroid constrictor implantation. ECG analysis highlighted an increase in the diameter of the left atria (LA) at two weeks post-operation as well as ischemic changes in the left ventricle (LV) and LA wall at four weeks post-operation. Echocardiography and MRI further detected a gradual increase in LA and LV volumes from two weeks post-operation. LV end diastolic and systolic volumes as well as LA end diastolic and systolic volume were also significantly higher in pig hearts post-operation when compared to baseline. Pathological changes were observed in the heart, which included scar tissue in the ischemic central area of the LV. Transmission electron microscopy highlighted the presence of contraction bands and edema surrounding the ischemia area, including inflammatory cell infiltration within the ischemic area. We have developed a pig model of IMR using the posterior mitral chordae tendineae rupture technique and implantation of an ameroid constrictor. The pathological features of this pig IMR model were found to mimic the natural history and progression of IMR in patients.

  18. One-year outcome of percutaneous mitral valve repair in patients with severe symptomatic mitral valve regurgitation

    PubMed Central

    Gotzmann, Michael; Sprenger, Isabell; Ewers, Aydan; Mügge, Andreas; Bösche, Leif

    2017-01-01

    AIM To investigate one-year outcomes after percutaneous mitral valve repair with MitraClip® in patients with severe mitral regurgitation (MR). METHODS Our study investigated consecutive patients with symptomatic severe MR who underwent MitraClip® implantation at the University Hospital Bergmannsheil from 2012 to 2014. The primary study end-point was all-cause mortality. Secondary end-points were degree of MR and functional status after percutaneous mitral valve repair. RESULTS The study population consisted of 46 consecutive patients (mean logistic EuroSCORE 32% ± 21%). The degree of MR decreased significantly (severe MR before MitraClip® 100% vs after MitraClip® 13%; P < 0.001), and the NYHA functional classes improved (NYHA III/IV before MitraClip® 98% vs after MitraClip® 35%; P < 0.001). The mortality rates 30 d and one year after percutaneous mitral valve repair were 4.3% and 19.5%, respectively. During the follow-up of 473 ± 274 d, 11 patients died (90% due to cardiovascular death). A pre-procedural plasma B-type natriuretic peptide level > 817 pg/mL was associated with all-cause mortality (hazard ratio, 6.074; 95%CI: 1.257-29.239; P = 0.012). CONCLUSION Percutaneous mitral valve repair with MitraClip® has positive effects on hemodynamics and symptoms. Despite the study patients’ multiple comorbidities and extremely high operative risk, one-year outcomes after MitraClip® are favorable. Elevated B-type natriuretic peptide levels indicate poorer mid-term survival. PMID:28163835

  19. Determination of correlation between backflow volume and mitral valve leaflet young modulus from two dimensional echocardiogram images

    NASA Astrophysics Data System (ADS)

    Jong, Rudiyanto P.; Osman, Kahar; Adib, M. Azrul Hisham M.

    2012-06-01

    Mitral valve prolapse without proper monitoring might lead to a severe mitral valve failure which eventually leads to a sudden death. Additional information on the mitral valve leaflet condition against the backflow volume would be an added advantage to the medical practitioner for their decision on the patients' treatment. A study on two dimensional echocardiography images has been conducted and the correlations between the backflow volume of the mitral regurgitation and mitral valve leaflet Young modulus have been obtained. Echocardiogram images were analyzed on the aspect of backflow volume percentage and mitral valve leaflet dimensions on different rates of backflow volume. Young modulus values for the mitral valve leaflet were obtained by using the principle of elastic deflection and deformation on the mitral valve leaflet. The results show that the backflow volume increased with the decrease of the mitral valve leaflet Young modulus which also indicate the condition of the mitral valve leaflet approaching failure at high backflow volumes. Mitral valve leaflet Young modulus values obtained in this study agreed with the healthy mitral valve leaflet Young modulus from the literature. This is an initial overview of the trend on the prediction of the behaviour between the fluid and the structure of the blood and the mitral valve which is extendable to a larger system of prediction on the mitral valve leaflet condition based on the available echocardiogram images.

  20. Double-disc gate valve

    DOEpatents

    Wheatley, Seth J.

    1979-01-01

    This invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewtih, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separtion of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve.

  1. Preoperative Three-Dimensional Valve Analysis Predicts Recurrent Ischemic Mitral Regurgitation after Mitral Annuloplasty

    PubMed Central

    Bouma, Wobbe; Lai, Eric K.; Levack, Melissa M.; Shang, Eric K.; Pouch, Alison M.; Eperjesi, Thomas J.; Plappert, Theodore J.; Yushkevich, Paul A.; Mariani, Massimo A.; Khabbaz, Kamal R.; Gleason, Thomas G.; Mahmood, Feroze; Acker, Michael A.; Woo, Y. Joseph; Cheung, Albert T.; Jackson, Benjamin M.; Gorman, Joseph H.; Gorman, Robert C.

    2015-01-01

    Background Valve repair for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings is characterized by high IMR recurrence rates. Patient-specific preoperative imaging-based risk stratification for recurrent IMR would optimize results. We sought to determine if pre-repair three-dimensional (3D) echocardiography combined with a novel valve modeling algorithm would be predictive of IMR recurrence 6 months after repair. Methods Intraoperative transesophageal real-time 3D echocardiography was performed in 50 patients undergoing undersized ring annuloplasty for IMR (and in 21 patients with normal mitral valves). A customized image analysis protocol was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥grade 2) was assessed with two-dimensional transthoracic echocardiography 6 months after repair. Results Preoperative annular geometry was similar in all IMR patients; and preoperative leaflet tethering was significantly higher in patients with recurrent IMR (n=13) as compared with patients in whom IMR did not recur IMR (n=37) (tethering index 3.91±1.01 vs. 2.90±1.17, P=0.008; tethering angles of A3 (23.5±8.9° vs. 14.4± 11.4°, P=0.012), P2 (44.4±8.8° vs. 28.2±17.0°, P=0.002), and P3 (35.2±6.0° vs. 18.6±12.7°, P<0.001)). Multivariate logistic regression analysis revealed preoperative P3 tethering angle as an independent predictor of IMR recurrence with an optimal cut-off value of 29.9° (AUC 0.92, 95%CI 0.84–1.00, P<0.001). Conclusions 3D echocardiography combined with valve modeling is predictive of recurrent IMR. Preoperative regional leaflet tethering of segment P3 is a strong independent predictor of IMR recurrence after undersized ring annuloplasty. In patients with a preoperative P3 tethering angle ≥29.9° chordal-sparing valve replacement rather than valve repair should be strongly considered. PMID:26688087

  2. The effect of sustained compression on oxygen metabolic transport in the intervertebral disc decreases with degenerative changes.

    PubMed

    Malandrino, Andrea; Noailly, Jérôme; Lacroix, Damien

    2011-08-01

    Intervertebral disc metabolic transport is essential to the functional spine and provides the cells with the nutrients necessary to tissue maintenance. Disc degenerative changes alter the tissue mechanics, but interactions between mechanical loading and disc transport are still an open issue. A poromechanical finite element model of the human disc was coupled with oxygen and lactate transport models. Deformations and fluid flow were linked to transport predictions by including strain-dependent diffusion and advection. The two solute transport models were also coupled to account for cell metabolism. With this approach, the relevance of metabolic and mechano-transport couplings were assessed in the healthy disc under loading-recovery daily compression. Disc height, cell density and material degenerative changes were parametrically simulated to study their influence on the calculated solute concentrations. The effects of load frequency and amplitude were also studied in the healthy disc by considering short periods of cyclic compression. Results indicate that external loads influence the oxygen and lactate regional distributions within the disc when large volume changes modify diffusion distances and diffusivities, especially when healthy disc properties are simulated. Advection was negligible under both sustained and cyclic compression. Simulating degeneration, mechanical changes inhibited the mechanical effect on transport while disc height, fluid content, nucleus pressure and overall cell density reductions affected significantly transport predictions. For the healthy disc, nutrient concentration patterns depended mostly on the time of sustained compression and recovery. The relevant effect of cell density on the metabolic transport indicates the disturbance of cell number as a possible onset for disc degeneration via alteration of the metabolic balance. Results also suggest that healthy disc properties have a positive effect of loading on metabolic transport. Such

  3. Medical Information on Optical Disc*

    PubMed Central

    Schipma, Peter B.; Cichocki, Edward M.; Ziemer, Susan M.

    1987-01-01

    Optical discs may permit a revolutionary change in the distribution and use of medical information. A single compact disc, similar in size to that used for digital audio recording, can contain over 500 million characters of information that is accessible by a Personal Computer. These discs can be manufactured at a cost lower than that of print on paper, at reasonable volumes. Software can provide the health care professional with nearly instantaneous access to the information. Thus, for the first time, the opportunity exists to have large local medical information collections. This paper describes an application of this technology in the field of Oncology.

  4. Minimally invasive approach for redo mitral valve surgery.

    PubMed

    Botta, Luca; Cannata, Aldo; Bruschi, Giuseppe; Fratto, Pasquale; Taglieri, Corrado; Russo, Claudio Francesco; Martinelli, Luigi

    2013-11-01

    Redo cardiac surgery represents a clinical challenge due to a higher rate of peri-operative morbidity and mortality. Mitral valve re-operations can be particularly demanding in patients with patent coronary artery bypass grafts, previous aortic valve replacement, calcified aorta or complications following a previous operation (abscesses, perivalvular leaks, or thrombosis). Risk of graft injuries, hemorrhage, the presence of dense adhesions and complex valve exposure can make redo valve operations challenging through a median sternotomy. In this review article we provide an overview of minimally invasive approaches for redo mitral valve surgery discussing indications, techniques, outcomes, concerns and controversies. Scientific literature about minimally invasive approach for redo mitral surgery was reviewed with a MEDLINE search strategy combining "mitral valve" with the following terms: 'minimally invasive', 'reoperation', and 'alternative approach'. The search was limited to the last ten years. A total of 168 papers were found using the reported search. From these, ten papers were identified to provide the best evidence on the subject. Mitral valve reoperations can be safely and effectively performed through a smaller right thoracotomy in the fourth intercostal space termed "mini" thoracotomy or "port access". The greatest potential benefit of a right mini-thoracotomy is the avoidance of sternal re-entry and limited dissection of adhesions, avoiding the risk of injury to cardiac structures or patent grafts. Good percentages of valve repair can be achieved. Mortality is low as well as major complications. Minimally invasive procedures with an unclamped aorta have the potential to combine the benefits of minimally invasive access and continuous myocardial perfusion. Less invasive trans-catheter techniques could be considered as the natural future evolution for management of structural heart disease and mitral reoperations. The safety and efficacy of these

  5. Minimally invasive approach for redo mitral valve surgery

    PubMed Central

    Cannata, Aldo; Bruschi, Giuseppe; Fratto, Pasquale; Taglieri, Corrado; Russo, Claudio Francesco; Martinelli, Luigi

    2013-01-01

    Redo cardiac surgery represents a clinical challenge due to a higher rate of peri-operative morbidity and mortality. Mitral valve re-operations can be particularly demanding in patients with patent coronary artery bypass grafts, previous aortic valve replacement, calcified aorta or complications following a previous operation (abscesses, perivalvular leaks, or thrombosis). Risk of graft injuries, hemorrhage, the presence of dense adhesions and complex valve exposure can make redo valve operations challenging through a median sternotomy. In this review article we provide an overview of minimally invasive approaches for redo mitral valve surgery discussing indications, techniques, outcomes, concerns and controversies. Scientific literature about minimally invasive approach for redo mitral surgery was reviewed with a MEDLINE search strategy combining “mitral valve” with the following terms: ‘minimally invasive’, ‘reoperation’, and ‘alternative approach’. The search was limited to the last ten years. A total of 168 papers were found using the reported search. From these, ten papers were identified to provide the best evidence on the subject. Mitral valve reoperations can be safely and effectively performed through a smaller right thoracotomy in the fourth intercostal space termed “mini” thoracotomy or “port access”. The greatest potential benefit of a right mini-thoracotomy is the avoidance of sternal re-entry and limited dissection of adhesions, avoiding the risk of injury to cardiac structures or patent grafts. Good percentages of valve repair can be achieved. Mortality is low as well as major complications. Minimally invasive procedures with an unclamped aorta have the potential to combine the benefits of minimally invasive access and continuous myocardial perfusion. Less invasive trans-catheter techniques could be considered as the natural future evolution for management of structural heart disease and mitral reoperations. The safety and

  6. Noninvasive assessment of the stenotic mitral valve orifice by two-dimensional echocardiography

    PubMed Central

    Jain, Surendra K.; Pechacek, Leonard W.; Decastro, Carlos M.; Garcia, Efrain; Hall, Robert J.

    1981-01-01

    Two-dimensional echocardiographic imaging of the mitral valve orifice was attempted in 26 patients with isolated mitral stenosis. The intention was to examine further the clinical usefulness and limitations of this technique for estimating the severity of mitral stenosis. Technically adequate recordings of the mitral orifice were obtained in 20 patients (77%). Mitral valve area calculated from echocardiography compared favorably to the valve area derived from cardiac catheterization with the use of the Gorlin formula (r = 0.95). The average difference between the two methods was 0.109 cm2. Two-dimensional echocardiography does provide clinically useful data for predicting the degree of mitral stenosis in the majority of patients provided that critical technical limitations are recognized. Images PMID:15216223

  7. Degenerative mitral valve disease-contemporary surgical approaches and repair techniques.

    PubMed

    Koprivanac, Marijan; Kelava, Marta; Alansari, Shehab; Javadikasgari, Hoda; Tappuni, Bassman; Mick, Stephanie; Marc, Gillinov A; Suri, Rakesh; Mihaljevic, Tomislav

    2017-01-01

    Given the increasing age of the US population and the accompanying rise in cardiovascular disease, we expect to see an increasing number of patients affected by degenerative mitral valve disease in a more complex patient population. Therefore, increasing the overall rate of mitral valve repair will become even more important than it is today, and the capability to provide a universally and uniformly accepted quality of repair will have important medical, economic, and societal implications. This article will describe preoperative and intraoperative considerations and the currently practiced mitral valve repair approaches and techniques. The aim of the article is to present our contemporary approach to mitral valve repair in the hope that it can be adopted at other institutions that may have low repair rates. Adoption of simple and reproducible mitral valve repair techniques is of paramount importance if we as a profession are to accomplish overall higher rates of mitral valve repair with optimal outcomes.

  8. Degenerative mitral valve disease-contemporary surgical approaches and repair techniques

    PubMed Central

    Kelava, Marta; Alansari, Shehab; Javadikasgari, Hoda; Tappuni, Bassman; Mick, Stephanie; Marc, Gillinov A.; Suri, Rakesh; Mihaljevic, Tomislav

    2017-01-01

    Given the increasing age of the US population and the accompanying rise in cardiovascular disease, we expect to see an increasing number of patients affected by degenerative mitral valve disease in a more complex patient population. Therefore, increasing the overall rate of mitral valve repair will become even more important than it is today, and the capability to provide a universally and uniformly accepted quality of repair will have important medical, economic, and societal implications. This article will describe preoperative and intraoperative considerations and the currently practiced mitral valve repair approaches and techniques. The aim of the article is to present our contemporary approach to mitral valve repair in the hope that it can be adopted at other institutions that may have low repair rates. Adoption of simple and reproducible mitral valve repair techniques is of paramount importance if we as a profession are to accomplish overall higher rates of mitral valve repair with optimal outcomes. PMID:28203540

  9. Design Issues in Video Disc Map Display.

    DTIC Science & Technology

    1984-10-01

    Tables: disc storage capacities under various conditions. Photos: map frames. Constanzo , D.J. (1984a), "The Potential for Video Disc Technology in...discs. Constanzo , D.J. (1984b), "Requirements and Specifications for Cartographic Video Discs", presented as a poster paper at the 1984 Army Science

  10. Enlivening Physics, a Local Video Disc Project.

    ERIC Educational Resources Information Center

    McInerney, M.

    1989-01-01

    Describes how to make and use an inexpensive video disc of physics demonstrations. Discusses the background, production of the disc, subject of the disc including angular momentum, "monkey and the hunter" experiment, Doppler shift, pressure of a constant volume of gas thermometer, and wave effects, and using the disc in classroom. (YP)

  11. Disc Golf: Teaching a Lifetime Activity

    ERIC Educational Resources Information Center

    Eastham, Susan L.

    2015-01-01

    Disc golf is a lifetime activity that can be enjoyed by students of varying skill levels and abilities. Disc golf follows the principles of ball golf but is generally easier for students to play and enjoy success. The object of disc golf is similar to ball golf and involves throwing a disc from the teeing area to the target in as few throws as…

  12. Decellularized allogeneic intervertebral disc: natural biomaterials for regenerating disc degeneration

    PubMed Central

    Hu, Zhijun; Chen, Kai; Shan, Zhi; Chen, Shuai; Wang, Jiying; Mo, Jian; Ma, Jianjun; Xu, Wenbing; Qin, An; Fan, Shunwu

    2016-01-01

    Intervertebral disc degeneration is associated with back pain and disc herniation. This study established a modified protocol for intervertebral disc (IVD) decellularization and prepared its extracellular matrix (ECM). By culturing mesenchymal stem cells (MSCs)(3, 7, 14 and 21 days) and human degenerative IVD cells (7 days) in the ECM, implanting it subcutaneously in rabbit and injecting ECM microparticles into degenerative disc, the biological safety and efficacy of decellularized IVD was evaluated both in vitro and in vivo. Here, we demonstrated that cellular components can be removed completely after decellularization and maximally retain the structure and biomechanics of native IVD. We revealed that allogeneic ECM did not evoke any apparent inflammatory reaction in vivo and no cytotoxicity was found in vitro. Moreover, IVD ECM can induce differentiation of MSCs into IVD-like cells in vitro. Furthermore, allogeneic ECM microparticles are effective on the treatment of rabbit disc degeneration in vivo. In conclusion, our study developed an optimized method for IVD decellularization and we proved decellularized IVD is safe and effective for the treatment of degenerated disc diseases. PMID:26933821

  13. Engineering alginate for intervertebral disc repair.

    PubMed

    Bron, Johannes L; Vonk, Lucienne A; Smit, Theodoor H; Koenderink, Gijsje H

    2011-10-01

    Alginate is frequently studied as a scaffold for intervertebral disc (IVD) repair, since it closely mimics mechanical and cell-adhesive properties of the nucleus pulposus (NP) of the IVD. The aim of this study was to assess the relation between alginate concentration and scaffold stiffness and find preparation conditions where the viscoelastic behaviour mimics that of the NP. In addition, we measured the effect of variations in scaffold stiffness on the expression of extracellular matrix molecules specific to the NP (proteoglycans and collagen) by native NP cells. We prepared sample discs of different concentrations of alginate (1%-6%) by two different methods, diffusion and in situ gelation. The stiffness increased with increasing alginate concentration, while the loss tangent (dissipative behaviour) remained constant. The diffusion samples were ten-fold stiffer than samples prepared by in situ gelation. Sample discs prepared from 2% alginate by diffusion closely matched the stiffness and loss tangent of the NP. The stiffness of all samples declined upon prolonged incubation in medium, especially for samples prepared by diffusion. The biosynthetic phenotype of native cells isolated from NPs was preserved in alginate matrices up to 4 weeks of culturing. Gene expression levels of extracellular matrix components were insensitive to alginate concentration and corresponding matrix stiffness, likely due to the poor adhesiveness of the cells to alginate. In conclusion, alginate can mimic the viscoelastic properties of the NP and preserve the biosynthetic phenotype of NP cells but certain limitations like long-term stability still have to be addressed.

  14. Pyrite discs in coal: evidence for fossilized bacterial colonies

    USGS Publications Warehouse

    Southam, G.; Donald, R.; Rostad, A.; Brock, C.

    2001-01-01

    Discs of pyrite from 1 to 3 mm in diameter and ∼100 μm thick were observed within fracture planes in coal from the Black Mesa coal deposit in northeastern Arizona. The pyrite discs were composed of aggregates of crystals, which suggested that sulfide mineral diagenesis had initiated at multiple nucleation sites and occurred prior to the compaction forces occurring during coal formation. Stable sulfur isotope analysis of the discs (δ34S = −31.7‰) supports a bacterial origin resulting from dissimilatory sulfate reduction. Fossilized bacteria on the disc surfaces (average = 27/100 μm2) appeared as halos when viewed using reflected light microscopy, but were lenticular by scanning electron microscopy, each microfossil being 2–3 μm in length. A fossilized bacterial colony (pyrite disc), 1 mm in diameter, would contain ∼2.1 × 107 microfossils. These microfossils were not observed on hydrothermal pyrite. Coating and in-filling of sulfate-reducing bacteria with iron disulfide during in vitro sulfide mineral diagenesis provide mechanisms to explain the preservation of the three-dimensional lenticular microfossils observed on the pyrite discs.

  15. Safety and feasibility of a novel adjustable mitral annuloplasty ring: a multicentre European experience†

    PubMed Central

    Andreas, Martin; Doll, Nicolas; Livesey, Steve; Castella, Manuel; Kocher, Alfred; Casselman, Filip; Voth, Vladimir; Bannister, Christina; Encalada Palacios, Juan F.; Pereda, Daniel; Laufer, Guenther; Czesla, Markus

    2016-01-01

    OBJECTIVES Recurrent mitral regurgitation is a significant problem after mitral valve repair in patients with functional valve disease. We report the safety and feasibility of a novel adjustable mitral annuloplasty device that permits downsizing of the anterior–posterior diameter late after initial surgery. METHODS In this multicentre, non-randomized, observational register, patients with moderate or severe mitral regurgitation undergoing surgical mitral valve repair with the MiCardia EnCorSQ™ Mitral Valve Repair system were evaluated. Patient characteristics, operative specifications and results as well as postoperative follow-up were collected for all five centres. RESULTS Ninety-four patients with a median age of 71 (64–75) years (EuroSCORE II 6.7 ± 6.3; 66% male, 48% ischaemic MR, 37% dilated cardiomyopathy and 15% degenerative disease) were included. Operative mortality was 1% and the 1-year survival was 93%. Ring adjustment was attempted in 12 patients at a mean interval of 9 ± 6 months after surgery. In three of these attempts, a technical failure occurred. In 1 patient, mitral regurgitation was reduced two grades, in 2 patients mitral regurgitation was reduced one grade and in 6 patients, mitral regurgitation did not change significantly. The mean grade of mitral regurgitation changed from 2.9 ± 0.9 to 2.1 ± 0.7 (P = 0.02). Five patients were reoperated after 11 ± 9 months (Ring dehiscence: 2; failed adjustment: 3). CONCLUSION We conclude that this device may provide an additional treatment option in patients with functional mitral regurgitation, who are at risk for reoperation due to recurrent mitral regurgitation. Clinical results in this complex disease were ambiguous and patient selection seems to be a crucial step for this device. Further trials are required to estimate the clinical value of this therapeutic concept. PMID:25694471

  16. The Mitral Valve Prolapsus : Quantification of the Regurgitation Flow Rate by Experimental Time-Dependant PIV

    DTIC Science & Technology

    2007-11-02

    The Mitral Valve Prolapsus : Quantification of the Regurgitation Flow Rate by Experimental Time-Dependant PIV. F. Billy1, D. Coisne1,2, L. Sanchez1... mitral valve insufficiency), assumes that the velocity field in the convergent region have hemispheric shapes and introduce miscalculation specially...upstream a prolaps model of regurgitant orifice based on 2D time dependent PIV reconstruction. Keywords- Mitral Valve , Prolapsus, Regurgitation Flow

  17. The frequency of binary star interlopers amongst transitional discs

    NASA Astrophysics Data System (ADS)

    Ruíz-Rodríguez, D.; Ireland, M.; Cieza, L.; Kraus, A.

    2016-12-01

    Using Non-Redundant Mask interferometry (NRM), we searched for binary companions to objects previously classified as transitional discs (TD). These objects are thought to be an evolutionary stage between an optically thick disc and optically thin disc. We investigate the presence of a stellar companion as a possible mechanism of material depletion in the inner region of these discs, which would rule out an ongoing planetary formation process in distances comparable to the binary separation. For our detection limits, we implement a new method of completeness correction using a combination of randomly sampled binary orbits and Bayesian inference. The selected sample of 24 TDs belongs to the nearby and young star-forming regions: Ophiuchus (˜130 pc), Taurus-Auriga (˜140 pc) and IC348 (˜220 pc). These regions are suitable to resolve faint stellar companions with moderate to high confidence levels at distances as low as 2 au from the central star. With a total of 31 objects, including 11 known TDs and circumbinary discs from the literature, we have found that a fraction of 0.38 ± 0.09 of the SEDs of these objects are likely due to the tidal interaction between a close binary and its disc, while the remaining SEDs are likely the result of other internal processes such as photoevaporation, grain growth, planet-disc interactions. In addition, we detected four companions orbiting outside the area of the truncation radii and propose that the IR excesses of these systems are due to a disc orbiting a secondary companion.

  18. The DISC1 promoter: characterization and regulation by FOXP2.

    PubMed

    Walker, Rosie M; Hill, Alison E; Newman, Alice C; Hamilton, Gillian; Torrance, Helen S; Anderson, Susan M; Ogawa, Fumiaki; Derizioti, Pelagia; Nicod, Jérôme; Vernes, Sonja C; Fisher, Simon E; Thomson, Pippa A; Porteous, David J; Evans, Kathryn L

    2012-07-01

    Disrupted in schizophrenia 1 (DISC1) is a leading candidate susceptibility gene for schizophrenia, bipolar disorder and recurrent major depression, which has been implicated in other psychiatric illnesses of neurodevelopmental origin, including autism. DISC1 was initially identified at the breakpoint of a balanced chromosomal translocation, t(1;11) (q42.1;14.3), in a family with a high incidence of psychiatric illness. Carriers of the translocation show a 50% reduction in DISC1 protein levels, suggesting altered DISC1 expression as a pathogenic mechanism in psychiatric illness. Altered DISC1 expression in the post-mortem brains of individuals with psychiatric illness and the frequent implication of non-coding regions of the gene by association analysis further support this assertion. Here, we provide the first characterization of the DISC1 promoter region. Using dual luciferase assays, we demonstrate that a region -300 to -177 bp relative to the transcription start site (TSS) contributes positively to DISC1 promoter activity, while a region -982 to -301 bp relative to the TSS confers a repressive effect. We further demonstrate inhibition of DISC1 promoter activity and protein expression by forkhead-box P2 (FOXP2), a transcription factor implicated in speech and language function. This inhibition is diminished by two distinct FOXP2 point mutations, R553H and R328X, which were previously found in families affected by developmental verbal dyspraxia. Our work identifies an intriguing mechanistic link between neurodevelopmental disorders that have traditionally been viewed as diagnostically distinct but which do share varying degrees of phenotypic overlap.

  19. Bulge Growth Through Disc Instabilities in High-Redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Bournaud, Frédéric

    The role of disc instabilities, such as bars and spiral arms, and the associated resonances, in growing bulges in the inner regions of disc galaxies have long been studied in the low-redshift nearby Universe. There it has long been probed observationally, in particular through peanut-shaped bulges (Chap. 14 10.1007/978-3-319-19378-6_14"). This secular growth of bulges in modern disc galaxies is driven by weak, non-axisymmetric instabilities: it mostly produces pseudobulges at slow rates and with long star-formation timescales. Disc instabilities at high redshift (z > 1) in moderate-mass to massive galaxies (1010 to a few 1011 M⊙ of stars) are very different from those found in modern spiral galaxies. High-redshift discs are globally unstable and fragment into giant clumps containing 108-9 M⊙ of gas and stars each, which results in highly irregular galaxy morphologies. The clumps and other features associated to the violent instability drive disc evolution and bulge growth through various mechanisms on short timescales. The giant clumps can migrate inward and coalesce into the bulge in a few 108 years. The instability in the very turbulent media drives intense gas inflows toward the bulge and nuclear region. Thick discs and supermassive black holes can grow concurrently as a result of the violent instability. This chapter reviews the properties of high-redshift disc instabilities, the evolution of giant clumps and other features associated to the instability, and the resulting growth of bulges and associated sub-galactic components.

  20. Eclipse Mapping of Accretion Discs

    NASA Astrophysics Data System (ADS)

    Baptista, R.

    The eclipse mapping method is an inversion technique that makes use of the information contained in eclipse light curves to probe the structure, the spectrum and the time evolution of accretion discs. In this review I present the basics of the method and discuss its different implementations. I summarize the most important results obtained to date and discuss how they have helped to improve our understanding of accretion physics, from testing the theoretical radial brightness temperature distribution and measuring mass accretion rates to showing the evolution of the structure of a dwarf novae disc throughout its outburst cycle, from isolating the spectrum of a disc wind to revealing the geometry of disc spiral shocks. I end with an outline of the future prospects.

  1. Tissue engineering: A live disc

    NASA Astrophysics Data System (ADS)

    Hukins, David W. L.

    2005-12-01

    A material-cell hybrid device that mimics the anatomic shape of the intervertebral disc has been made and successfully implanted into mice to show that tissue engineering may, in the future, benefit sufferers from back pain.

  2. Disc Golf, a Growing Sport

    PubMed Central

    Nelson, Joseph T.; Jones, Richard E.; Runstrom, Michael; Hardy, Jolene

    2015-01-01

    Background Disc golf is a sport played much like traditional golf, but rather than using a ball and club, players throw flying discs with various throwing motions. It has been played by an estimated 8 to 12 million people in the United States. Like all sports, injuries sustained while playing disc golf are not uncommon. Although formalized in the 1970s, it has grown at a rapid pace; however, disc golf–related injuries have yet to be described in the medical literature. Purpose To describe the most common injuries incurred by disc golf players while comparing the different types of throwing styles. Study Design Descriptive epidemiology study. Methods The data in this study were collected from 883 disc golf players who responded to an online survey collected over a 1-month period. Respondents answered 49 questions related to demographics, experience, style of play, and injury details. Using a chi-square analysis, common injuries sustained in players using backhand and forehand throwing styles were compared. Results More than 81% of respondents stated that they had sustained an injury playing disc golf, including injuries to the elbow (n = 325), shoulder (n = 305), back (n = 218), and knee (n = 199). The injuries were most commonly described as a muscle strain (n = 241), sprain (n = 162), and tendinitis (n = 145). The type of throw primarily used by players varied, with 86.2% using backhand, 12.7% using forehand, and 1.1% using an overhead throw. Players using a forehand throw were more likely to sustain an elbow injury (P = .014). Many players (n = 115) stated they had undergone surgery due to a disc golf–related injury, with the most common surgeries including meniscal, shoulder, spine, and foot/ankle surgeries. Conclusion The majority of surveyed disc golfers sustained at least 1 injury while playing disc golf, with many requiring surgery. The types of injuries sustained by players varied by the types of throw primarily used. As the sport of disc golf continues

  3. Percutaneous diode laser disc nucleoplasty

    NASA Astrophysics Data System (ADS)

    Menchetti, P. P.; Longo, Leonardo

    2004-09-01

    The treatment of herniated disc disease (HNP) over the years involved different miniinvasive surgical options. The classical microsurgical approach has been substituted over the years both by endoscopic approach in which is possible to practice via endoscopy a laser thermo-discoplasty, both by percutaneous laser disc nucleoplasty. In the last ten years, the percutaneous laser disc nucleoplasty have been done worldwide in more than 40000 cases of HNP. Because water is the major component of the intervertebral disc, and in HNP pain is caused by the disc protrusion pressing against the nerve root, a 980 nm Diode laser introduced via a 22G needle under X-ray guidance and local anesthesia, vaporizes a small amount of nucleous polposus with a disc shrinkage and a relief of pressure on nerve root. Most patients get off the table pain free and are back to work in 5 to 7 days. Material and method: to date, 130 patients (155 cases) suffering for relevant symptoms therapy-resistant 6 months on average before consulting our department, have been treated. Eightyfour (72%) males and 46 (28%) females had a percutaneous laser disc nucleoplasty. The average age of patients operated was 48 years (22 - 69). The level of disc removal was L3/L4 in 12 cases, L4/L5 in 87 cases and L5/S1 in 56 cases. Two different levels were treated at the same time in 25 patients. Results: the success rate at a minimum follow-up of 6 months was 88% with a complication rate of 0.5%.

  4. Effects of increasing flow rate on aortic stenotic indices: evidence from percutaneous transvenous balloon dilatation of the mitral valve in patients with combined aortic and mitral stenosis.

    PubMed Central

    Lee, T. M.; Su, S. F.; Chen, M. F.; Liau, C. S.; Lee, Y. T.

    1996-01-01

    OBJECTIVES: To investigate the effects of transvalvar flow rate on aortic valve resistance and valve area after percutaneous transvenous balloon dilatation of the mitral valve in a homogeneous group of patients with rheumatic heart disease. DESIGN: Retrospective analysis of 12 patients with combined aortic and mitral stenosis who had undergone balloon dilatation of the mitral valve over a period of 9 years. SETTING: Tertiary referral centre. PATIENTS: Twelve (8 women, 4 men; mean (SD) age 37 (9) of 227 consecutive patients with critical mitral stenosis undergoing transvenous balloon dilation of the mitral valve in the centre also had aortic stenosis, defined as a transaortic pressure gradient of more than 25 mm Hg measured at a catheterisation study before valvuloplasty. INTERVENTIONS: Echocardiographic variables (mitral valve area measured by the pressure half-time method and planimetry, and the aortic valve area derived from the continuity equation) and haemodynamic measurements (cardiac output, left ventricular mean systolic pressure, aortic mean pressure, transaortic valve pressure gradient, mitral valve and aortic valve areas derived from the Gorlin formula, and aortic valve resistance) were assessed before and after transvenous balloon dilatation of the mitral valve. Follow up catheterisation to measure haemodynamic variables was performed one week after mitral valvuloplasty. RESULTS: Mean transaortic flow rate increased 33% after mitral valvuloplasty (from 198 (68) to 254 (41) ml/s, P = 0.002). Aortic valve areas derived from the Gorlin formula were significantly increased from 0.57 (0.12) to 0.73 (0.14) cm2 (P = 0.006) after mitral valvuloplasty. However, aortic valve area and valve resistance derived from the continuity equation were independent of the increase in flow rate after mitral valvuloplasty (from 1.29 (0.35) to 1.30 (0.29) cm2 and from 317 (65) to 259 (75) dyn.s.cm-5, both P = NS). CONCLUSION: The Gorlin-derived aortic valve area tends to be flow

  5. Beating heart mitral valve repair with integrated ultrasound imaging

    NASA Astrophysics Data System (ADS)

    McLeod, A. Jonathan; Moore, John T.; Peters, Terry M.

    2015-03-01

    Beating heart valve therapies rely extensively on image guidance to treat patients who would be considered inoperable with conventional surgery. Mitral valve repair techniques including the MitrClip, NeoChord, and emerging transcatheter mitral valve replacement techniques rely on transesophageal echocardiography for guidance. These images are often difficult to interpret as the tool will cause shadowing artifacts that occlude tissue near the target site. Here, we integrate ultrasound imaging directly into the NeoChord device. This provides an unobstructed imaging plane that can visualize the valve lea ets as they are engaged by the device and can aid in achieving both a proper bite and spacing between the neochordae implants. A proof of concept user study in a phantom environment is performed to provide a proof of concept for this device.

  6. Asymptomatic and isolated accessory mitral valve tissue in an adult.

    PubMed

    Hisatomi, Kazuki; Hashizume, Koji; Tanigawa, Kazuyoshi; Miura, Takashi; Matsukuma, Seiji; Yokose, Shogo; Sumi, Mizuki; Eishi, Kiyoyuki

    2016-02-01

    Accessory mitral valve (AMV) tissue is a congenital anomaly that occurs in association with other congenital anomalies, and is an uncommon cause of left ventricular outflow tract obstruction. It is usually detected in early childhood when accompanied by symptoms of obstruction of the left ventricular outflow tract, and is rarely diagnosed in adults. We present a case of a 53-year-old man who was referred to our institution for evaluation of a systolic heart murmur. Echocardiography disclosed a diagnosis of AMV tissue. This case was uncommon because of the lack of severe obstruction of left ventricular outflow, cardiac symptoms, or other cardiac anomalies. We were able to carry out surgical resection of AMV tissue to avert possible progression of aortic insufficiency and the risk of a cerebrovascular embolization. The patient's postoperative course was uneventful, and postoperative echocardiography showed no residual accessory mitral tissue.

  7. [Mitral valve replacement in a patient with Sheehan's syndrome].

    PubMed

    Morokuma, H; Nakayama, Y; Minematsu, N

    2008-09-01

    Sheehan' syndrome is caused by pituitary apoplexy occurring during parturition and results in hypopituitarism, adrenal insufficiency and hypothyroidism. A 66-year-old woman with Sheehan's syndrome had received corticosteroids and thyroid hormones for about 18 years. The patient underwent mitral valve replacement for mitral regurgitation. Intraoperatively, just after the initiation of cardiopulmonary bypass, hypotension and severe edema suddenly occurred. Crystalloid fluid was rapidly administered to increase intravascular volumes. Postoperatively the body weight increased by 9.4 kg. The patient was intubated for 64 hours, stayed in the intensive care unit (ICU) for 7 days and was discharged from hospital on the postoperative day 36. Careful perioperative hormone supplementation is necessary for patients with Sheehan's syndrome.

  8. Left atrial myxoma, ruptured chordae tendinae causing mitral regurgitation and coronary artery disease.

    PubMed

    Kumar, Bhupesh; Raj, Ravi; Jayant, Aveek; Kuthe, Sachin

    2014-01-01

    Mitral regurgitation is uncommon with left atrial myxoma. The echocardiographic assessment of presence of mitral regurgitation and its severity are impaired by the presence of left atrial myxoma. We describe an uncommon association of left atrial myxoma with coronary artery disease and mitral regurgitation. MR was reported as mild on pre-operative transthoracic echocardiography but found to be severe due to ruptured chordae tendinae during intra-operative transesophageal echocardiography, which lead to change in the surgical plan to mitral valve replacement in addition to excision of myxoma.

  9. Infective Endocarditis of the Aortic Valve with Anterior Mitral Valve Leaflet Aneurysm.

    PubMed

    Tomsic, Anton; Li, Wilson W L; van Paridon, Marieke; Bindraban, Navin R; de Mol, Bas A J M

    2016-08-01

    Mitral valve leaflet aneurysm is a rare and potentially devastating complication of aortic valve endocarditis. We report the case of a 48-year-old man who had endocarditis of the native aortic valve and a concomitant aneurysm of the anterior mitral valve leaflet. Severe mitral regurgitation occurred after the aneurysm perforated. The patient showed no signs of heart failure and completed a 6-week regimen of antibiotic therapy before undergoing successful aortic and mitral valve replacement. In addition to the patient's case, we review the relevant medical literature.

  10. Transcatheter valve-in-valve implantation for failed mitral prosthesis: the first experience in Japan.

    PubMed

    Tada, Norio; Enta, Yusuke; Sakurai, Mie; Ootomo, Tatsushi; Hata, Masaki

    2017-01-01

    An 82-year-old woman had a history of mitral valve replacement with a 25-mm MOSAIC (Medtronic, USA) for severe mitral regurgitation (MR) 8 years previously. Recently, she developed heart failure due to MR secondary to prosthetic valve failure. She underwent transcatheter valve-in-valve implantation with a 23-mm SAPIEN XT (Edwards Lifesciences, USA) to the prosthetic mitral valve by transapical approach. To our knowledge, this is the first reported case of transcatheter valve implantation for failed mitral prosthetic valve using valve-in-valve technique in Japan.

  11. CTS Trials Network: A paradigm shift in the surgical treatment of moderate ischemic mitral regurgitation?

    PubMed

    Afifi, Ahmed

    2015-01-01

    The Cardiothoracic Surgery Trials Network has reported results of the one-year follow up of their randomized trial "Surgical Treatment of Moderate Ischemic Mitral Regurgitation". They studied 301 patients with moderate ischemic mitral regurgitation (IMR) undergoing coronary artery bypass grafting (CABG) with or without mitral repair with the primary end-point of change in left ventricular end-diastolic volume index (LVEDVI) at one year and multiple clinical and echocardiographic secondary endpoints. Although their results were against repairing the mitral valve, the debate on surgical management of moderate IMR remains unsettled.

  12. CTS Trials Network: A paradigm shift in the surgical treatment of moderate ischemic mitral regurgitation?

    PubMed Central

    Afifi, Ahmed

    2015-01-01

    The Cardiothoracic Surgery Trials Network has reported results of the one-year follow up of their randomized trial “Surgical Treatment of Moderate Ischemic Mitral Regurgitation”. They studied 301 patients with moderate ischemic mitral regurgitation (IMR) undergoing coronary artery bypass grafting (CABG) with or without mitral repair with the primary end-point of change in left ventricular end-diastolic volume index (LVEDVI) at one year and multiple clinical and echocardiographic secondary endpoints. Although their results were against repairing the mitral valve, the debate on surgical management of moderate IMR remains unsettled. PMID:26779511

  13. State of the mitral valve in rabbits with hypokinesia

    NASA Technical Reports Server (NTRS)

    Strelkovska, V. Y.

    1979-01-01

    In hypokinesia, edema of all the layers of the mitral value was observed, which resulted in morphological changes of the cellular and noncellular components. An increase in ratio of elastic and collagenic fibers in the value was also observed along with and changes in their structural and staining properties. The observed changes can limit valve mobility and can result in manifestations of cardiac valve insufficiency, which is found clinically.

  14. Malfunctioning Starr-Edwards mitral valve 21 years after installation.

    PubMed

    Sakata, K; Ishikawa, S; Ohtaki, A; Otani, Y; Suzuki, M; Kawashima, O; Morishita, Y

    1997-02-01

    Two cases of malfunctioning Starr-Edwards cloth-covered mitral valve prostheses requiring reoperation are presented. Both cases underwent successful surgical repair 21 years after the valve replacement. The causes were a disturbance of the poppet during the opening movement due to excessive tissue ingrowth and a paravalvular leak associated with a tear of the valve seat. Replacement of the Starr-Edwards valve prosthesis more than 20 years after the initial installation has not been reported.

  15. Malfunction of Cutter-Smeloff mitral prosthesis. An echocardiographic diagnosis.

    PubMed

    Behi, F; Chang, S; Welch, T

    1978-02-01

    Progression of intermittent partial or total impaction of the poppet from a prosthetic mitral valve may be difficult to evaluate in patients with chronic obstructive pulmonary disease and atrial fibrillation. Heart sounds may be distant; opening and closing clicks of the poppet are muffled and irregular. Echocardiography provides a noninvasive method to detect early prosthetic malfunction at a time when the patient is clinically asymptomatic.

  16. Occurrence of mitral valve insufficiency in clinically healthy Beagle dogs.

    PubMed

    Vörös, Károly; Szilvási, Viktória; Manczur, Ferenc; Máthé, Ákos; Reiczigel, Jenő; Nolte, Ingo; Hungerbühler, Stephan

    2015-12-01

    Chronic degenerative valve disease (CDVD) is the most common cardiac disease in dogs, usually resulting in mitral valve insufficiency (MVI). The goal of this study was to investigate the occurrence of MVI in clinically healthy Beagle populations. A total of 79 adult healthy Beagles (41 females and 38 males; age: 5.6 ± 2.7 years, range 1.4 to 11.7 years) were examined. The diagnosis of MVI was based on the detection of a systolic murmur heard above the mitral valve, and was confirmed by colour flow Doppler (CFD) echocardiography. Systolic mitral valve murmurs were detected in 20/79 dogs (25.3%), of them 11 males and 9 females with no statistically significant gender difference (P = 0.6059). The strength of the murmur on the semi-quantitative 0/6 scale yielded intensity grade 1/6 in 10 dogs, grade 2/6 in 4 dogs, and grade 3/6 in 6 dogs. Mild to moderate MVI was detected by CFD in all these 20 dogs with systolic murmurs. Of them, 17 dogs had mild and 3 demonstrated moderate MVI, showing 10-30% and 30-50% regurgitant jets compared to the size of the left atrium, respectively. The age of dogs with MVI was 7.1 ± 2.3 years, which was significantly different from that of dogs without MVI (5.1 ± 2.7 years, P = 0.0029). No significant differences in body weight (P = 0.1724) were found between dogs with MVI (13.8 ± 2.8 kg) and those without MVI (12.8 ± 3.0 kg). Mitral valve disease causing MVI is relatively common in Beagle dogs, just like in other small breed dogs reported in the literature.

  17. Real‐Time 3‐Dimensional Dynamics of Functional Mitral Regurgitation: A Prospective Quantitative and Mechanistic Study

    PubMed Central

    Topilsky, Yan; Vaturi, Ori; Watanabe, Nozomi; Bichara, Valentina; Nkomo, Vuyisile T.; Michelena, Hector; Le Tourneau, Thierry; Mankad, Sunil V.; Park, Soon; Capps, Mary Ann; Suri, Rakesh; Pislaru, Sorin V.; Maalouf, Joseph; Yoshida, Kiyoshi; Enriquez‐Sarano, Maurice

    2013-01-01

    Background Three‐dimensional transthoracic echocardiography (3D‐TTE) with dedicated software permits quantification of mitral annulus dynamics and papillary muscle motion throughout the cardiac cycle. Methods and Results Mitral apparatus 3D‐TTE was acquired in controls (n=42), patients with left ventricle dysfunction and functional mitral regurgitation (LVD‐FMR; n=43) or without FMR (LVD‐noMR, n=35). Annulus in both normal and LVD‐noMR subjects displayed saddle shape accentuation in early‐systole (ratio of height to intercommissural diameter, 10.6±3.7 to 13.5±4.0 in normal and 9.1±4.3 to 12.6±3.6 in LVD‐noMR; P<0.001 for diastole to early‐systole motion, P=NS between those groups). In contrast, saddle shape was unchanged from diastole in FMR patients (10.0±6.4 to 8.0±5.2; P=NS, P<0.05 compared to both other groups). Papillary tips moved symmetrically towards to the midanterior annulus in control and LVD‐noMR subjects, maintaining constant ratio of the distances between both tips to midannulus (PtAR) throughout systole. In LVD‐FMR patients midsystolic posterior papillary tip to anterior annulus distance was increased, resulting in higher PtAR (P=0.05 compared to both other groups). Mechanisms of early‐ and midsystolic FMR differed between different etiologies of LV dysfunction. In patients with anterior MI and global dysfunction annular function and dilatation were the dominant parameters, while papillary muscle motion was the predominant determinant of FMR in patients with inferior MI. Conclusions Inadequate early‐systolic annular contraction and saddle‐shape accentuation in patients with impaired LV contribute to early–mitral incompetency. Asymmetric papillary tip movement towards the midanterior annulus is a major determinant of mid‐ and late‐systolic functional mitral regurgitation. PMID:23727698

  18. A Review of Animal Models of Intervertebral Disc Degeneration: Pathophysiology, Regeneration, and Translation to the Clinic

    PubMed Central

    Ghosh, Peter

    2016-01-01

    Lower back pain is the leading cause of disability worldwide. Discogenic pain secondary to intervertebral disc degeneration is a significant cause of low back pain. Disc degeneration is a complex multifactorial process. Animal models are essential to furthering understanding of the degenerative process and testing potential therapies. The adult human lumbar intervertebral disc is characterized by the loss of notochordal cells, relatively large size, essentially avascular nature, and exposure to biomechanical stresses influenced by bipedalism. Animal models are compared with regard to the above characteristics. Numerous methods of inducing disc degeneration are reported. Broadly these can be considered under the categories of spontaneous degeneration, mechanical and structural models. The purpose of such animal models is to further our understanding and, ultimately, improve treatment of disc degeneration. The role of animal models of disc degeneration in translational research leading to clinical trials of novel cellular therapies is explored. PMID:27314030

  19. Evolution of protoplanetary discs with magnetically driven disc winds

    NASA Astrophysics Data System (ADS)

    Suzuki, Takeru K.; Ogihara, Masahiro; Morbidelli, Alessandro; Crida, Aurélien; Guillot, Tristan

    2016-12-01

    Aims: We investigate the evolution of protoplanetary discs (PPDs) with magnetically driven disc winds and viscous heating. Methods: We considered an initially massive disc with 0.1 M⊙ to track the evolution from the early stage of PPDs. We solved the time evolution of surface density and temperature by taking into account viscous heating and the loss of mass and angular momentum by the disc winds within the framework of a standard α model for accretion discs. Our model parameters, turbulent viscosity, disc wind mass-loss, and disc wind torque, which were adopted from local magnetohydrodynamical simulations and constrained by the global energetics of the gravitational accretion, largely depends on the physical condition of PPDs, particularly on the evolution of the vertical magnetic flux in weakly ionized PPDs. Results: Although there are still uncertainties concerning the evolution of the vertical magnetic flux that remains, the surface densities show a large variety, depending on the combination of these three parameters, some of which are very different from the surface density expected from the standard accretion. When a PPD is in a wind-driven accretion state with the preserved vertical magnetic field, the radial dependence of the surface density can be positive in the inner region <1-10 au. The mass accretion rates are consistent with observations, even in the very low level of magnetohydrodynamical turbulence. Such a positive radial slope of the surface density strongly affects planet formation because it inhibits the inward drift or even causes the outward drift of pebble- to boulder-sized solid bodies, and it also slows down or even reversed the inward type-I migration of protoplanets. Conclusions: The variety of our calculated PPDs should yield a wide variety of exoplanet systems.

  20. Non-invasive diagnosis of mitral regurgitation by Doppler echocardiography.

    PubMed Central

    Blanchard, D; Diebold, B; Peronneau, P; Foult, J M; Nee, M; Guermonprez, J L; Maurice, P

    1981-01-01

    The value of Doppler echocardiography for the non-invasive diagnosis of mitral regurgitation was studied blindly in 161 consecutive invasively investigated adult patients. Regurgitation was graded from 0 to 3 at selective left ventricular angiography. The Doppler echocardiographic examination was considered to be positive when a disturbed systolic flow was found within the left atrium behind the aorta or the anterior leaflet of the mitral valve. The test was considered to be negative in the absence of a regurgitant jet. The level of the signal to noise ratio was checked by the recording of the ventricular filling flow. The study was performed in 131 cases from the left side of the sternum and in 101 cases from the apex. There were no false positives and thus the specificity was 100 per cent. The 20 false negatives were all in patients with grade 1 regurgitation. Thus only some (33%) instances of mild regurgitation were misdiagnosed, and the sensitivity for moderate to severe mitral regurgitation was 100 per cent. PMID:7236465

  1. Maze permutations during minimally invasive mitral valve surgery

    PubMed Central

    2015-01-01

    Surgical ablation for atrial fibrillation is most frequently done in the concomitant setting, and most commonly with mitral valve surgery. Minimally invasive surgical techniques for the treatment of atrial fibrillation have developed contemporaneously with techniques for minimally invasive mitral valve surgery. As in traditional surgery for atrial fibrillation, there are many different permutations of ablations for the less invasive approaches. Lesion sets can vary from simple pulmonary vein isolation (PVI) to full bi-atrial lesions that completely reproduce the traditional cut-and-sew Cox Maze III procedure with variable efficacy in restoring sinus rhythm. Additionally, treatment of the atrial appendage can be done through minimally invasive approaches without any ablation at all in an attempt to mitigate the risk of stroke. Finally, hybrid procedures combining minimally invasive surgery and catheter-based ablation are being developed that might augment surgical treatment of atrial fibrillation at the time of minimally invasive mitral valve repair. These various permutations and their results are reviewed. PMID:26539352

  2. Mitral valve repair is not always needed in patients with functional mitral regurgitation undergoing coronary artery bypass grafting and/or aortic valve replacement

    PubMed Central

    Lindeboom, J.E.; Jaarsma, W.; Kelder, J.C.; Morshuis, W.J.; Visser, C.A.

    2005-01-01

    Background and aim Functional mitral regurgitation (FMR) is defined as mitral regurgitation in the absence of intrinsic valvular abnormalities. We prospectively evaluated the effect of coronary artery bypass grafting (CABG) and/or aortic valve replacement (AVR), without additional mitral valve repair, on the degree of moderate or severe FMR. Study design and methods From a cohort of 2829 patients undergoing CABG and/or AVR in the St. Antonius Hospital, 67 patients were identified with moderate or severe FMR by transthoracic and transoesophageal Doppler echocardiography. Results Two out of the 67 patients (3%) died perioperatively. During follow-up (3-18 months) mitral regurgitation decreased by one grade in 29 patients, by two grades in 28, by three grades in five patients and remained unchanged in one patient (p=0.0001). Of all patients, 85% had grade I mitral regurgitation or less. Grade II mitral regurgitation remained in nine patients with a previous large myocardial infarction and/or annular calcifications. NYHA class improved from 3.1+0.5 to 1.4+0.4 (p=0.0001). Ejection fraction increased from 46 to 55% (p=0.0001). Overall, left atrial and left ventricular end-diastolic dimensions decreased significantly. In contrast, no decrease in dimensions was seen in patients with postoperative grade II mitral regurgitation. Conclusion FMR may improve significantly following CABG and/or AVR, although a previous large myocardial infarction and/or annular calcifications may affect outcome. PMID:25696484

  3. Preclinical and clinical experience with a viscoelastic total disc replacement

    PubMed Central

    Rischke, Burkhard; Ross, Raymond S.; Jollenbeck, Boris A.; Zimmers, Kari B.; Defibaugh, Neal D.

    2011-01-01

    Background The purpose of this study is to describe the mechanical durability and the clinical and radiographic outcomes of a viscoelastic total disc replacement (VTDR). The human intervertebral disc is a complex, viscoelastic structure, permitting and constraining motion in 3 axes, thus providing stability. The ideal disc replacement should be viscoelastic and deformable in all directions, and it should restore disc height and angle. Methods Mechanical testing was conducted to validate the durability of the VTDR, and a clinical study was conducted to evaluate safety and performance. Fifty patients with single-level, symptomatic lumbar degenerative disc disease at L4-5 or L5-S1 were enrolled in a clinical trial at 3 European sites. Patients were assessed clinically and radiographically for 2 years by the Oswestry Disability Index (ODI), a visual analog scale (VAS), and independent radiographic analyses. Results The VTDR showed a fatigue life in excess of 50 million cycles (50-year equivalent) and a physiologically appropriate level of stiffness, motion, geometry, and viscoelasticity. We enrolled 28 men and 22 women in the clinical study, with a mean age of 40 years. Independent quantitative radiographic assessment indicated that the VTDR restored and maintained disc height and lordosis while providing physiologic motion. Mean ODI scores decreased from 48% preoperatively to 23% at 2 years’ follow-up. Mean VAS low-back pain scores decreased from 7.1 cm to 2.9 cm. Median scores indicated that half of the patient population had ODI scores below 10% and VAS low-back pain scores below 0.95 cm at 2 years. Conclusions The VTDR has excellent durability and performs clinically and radiographically as intended for the treatment of symptomatic lumbar degenerative disc disease. Clinical Relevance The VTDR is intended to restore healthy anatomic properties and stability characteristics to the spinal segment. This study is the first to evaluate a VTDR in a 50-patient

  4. Patient-prosthesis mismatch in the mitral position affects midterm survival and functional status

    PubMed Central

    Bouchard, Denis; Eynden, Frédéric Vanden; Demers, Philippe; Perrault, Louis P; Carrier, Michel; Cartier, Raymond; Basmadjian, Arsène J; Pellerin, Michel

    2010-01-01

    BACKGROUND: The definition and incidence of patient-prosthesis mismatch (PPM) in the mitral position are unclear. OBJECTIVES: To determine the impact of PPM on late survival and functional status after mitral valve replacement with a mechanical valve. METHODS: Between 1992 and 2005, 714 patients (mean [± SD] age 60±10 years) underwent valve replacement with either St Jude (St Jude Medical Inc, USA) (n=295) or Carbomedics (Sulzer Carbomedics Inc, USA) (n=419) valves. There were 52 concomitant procedures (50 tricuspid annuloplasties, 25 foramen oval closures and 20 radiofrequency mazes). The mean clinical follow-up period was 4.4±3.3 years. The severity of PPM was established with cut-off values for an indexed effective orifice area (EOAi) of lower than 1.2 cm2/m2, lower than 1.3 cm2/m2 and lower than 1.4 cm2/m2. Parametric and nonparametric tests were used to determine predictors of outcome. RESULTS: The prevalence of PPM was 3.7%, 10.1% and 23.5% when considering values of lower than 1.2 cm2/m2, lower than 1.3 cm2/m2 and lower than 1.4 cm2/m2, respectively. When considering functional improvement, patients with an EOAi of 1.4 cm2/m2 or greater had a better outcome than those with an EOAi of lower than 1.4 cm2/m2 (OR 1.98; P=0.03). When building a Cox-proportional hazard model, PPM with an EOAi of less than 1.3 cm2/m2 was an independent predictive factor for midterm survival (HR 2.24, P=0.007). Other factors affecting survival were age (HR 1.039), preoperative New York Heart Association class (HR 1.96) and body surface area (HR 0.31). CONCLUSIONS: In a large cohort of patients undergoing mitral valve replacement with mechanical prostheses, PPM defined as an EOAi of lower than 1.3 cm2/m2 significantly decreased midterm survival. This level of PPM was observed in 10.2% of patients. Patients with an EOAi of 1.4 cm2/m2 or greater had greater improvement of their functional status. PMID:21165362

  5. Changes in intervertebral disc cross-sectional area with bed rest and space flight

    NASA Technical Reports Server (NTRS)

    LeBlanc, A. D.; Evans, H. J.; Schneider, V. S.; Wendt, R. E. 3rd; Hedrick, T. D.

    1994-01-01

    STUDY DESIGN. We measured the cross-sectional area of the intervertebral discs of normal volunteers after an overnight rest; before, during, and after 5 or 17 weeks of bed rest; and before and after 8 days of weightlessness. OBJECTIVES. This study sought to determine the degree of expansion of the lumbar discs resulting from bed rest and space flight. SUMMARY OF BACKGROUND DATA. Weightlessness and bed rest, an analog for weightlessness, reduce the mechanical loading on the musculoskeletal system. When unloaded, intervertebral discs will expand, increasing the nutritional diffusion distance and altering the mechanical properties of the spine. METHODS. Magnetic resonance imaging was used to measure the cross-sectional area and transverse relaxation time (T2) of the intervertebral discs. RESULTS. Overnight or longer bed rest causes expansion of the disc area, which reaches an equilibrium value of about 22% (range 10-40%) above baseline within 4 days. Increases in disc area were associated with modest increases in disc T2. During bed rest, disc height increased approximately 1 mm, about one-half of previous estimates based on body height measurements. After 5 weeks of bed rest, disc area returned to baseline within a few days of ambulation, whereas after 17 weeks, disc area remained above baseline 6 weeks after reambulation. After 8 days of weightlessness, T2, disc area, and lumbar length were not significantly different from baseline values 24 hours after landing. CONCLUSIONS. Significant adaptive changes in the intervertebral discs can be expected during weightlessness. These changes, which are rapidly reversible after short-duration flights, may be an important factor during and after long-duration missions.

  6. Arrhythmias in mitral valve prolapse: relation to anterior mitral leaflet thickening, clinical variables, and color Doppler echocardiographic parameters.

    PubMed

    Zuppiroli, A; Mori, F; Favilli, S; Barchielli, A; Corti, G; Montereggi, A; Dolara, A

    1994-11-01

    Atrial and ventricular arrhythmias have been reported with variable incidence in symptomatic patients with mitral valve prolapse (MVP). The role of clinical and echocardiographic parameters as predictors for arrhythmias still needs to be clarified. One hundred nineteen consecutive patients (56 women and 63 men, mean age 40 +/- 17 years) with echocardiographically diagnosed MVP were examined. A complete echocardiographic study (M-mode, two-dimensional, and Doppler) and 24-hour electrocardiographic monitoring were performed in all patients. Complex atrial arrhythmias (CAAs) included atrial couplets, atrial tachycardia, and paroxysmal or sustained atrial flutter or fibrillation. Complex ventricular arrhythmias (CVAs) included multiform ventricular premature contractions (VPCs), VPC couplets, and runs of three or more sequential VPCs (salvos of ventricular tachycardia). The relation between complex arrhythmias and clinical parameters (age and gender) and echocardiographic parameters (left atrial and left ventricular dimensions, anterior mitral leaflet thickness [AMLT], and presence and severity of mitral regurgitation) was evaluated by multiple logistic regression analysis. CAA were present in 14% of patients and CVA in 30%. According to multiple logistic modeling, CAA correlated separately in the univariate analysis with age, presence of MR, and left ventricular and left atrial diameters; age was the only independent predictor (p < 0.001). CVA, in the univariate analysis, correlated with age, female gender, left ventricular end-diastolic diameter, and AMLT; only female gender and AMLT were independent predictors in the multivariate analysis (p < 0.01). The incidence of mitral regurgitation (59%) was higher than expected in a general population of MVP patients.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Value of Robotically Assisted Surgery for Mitral Valve Disease

    PubMed Central

    Mihaljevic, Tomislav; Koprivanac, Marijan; Kelava, Marta; Goodman, Avi; Jarrett, Craig; Williams, Sarah J.; Gillinov, A. Marc; Bajwa, Gurjyot; Mick, Stephanie L.; Bonatti, Johannes; Blackstone, Eugene H.

    2014-01-01

    Importance The value of robotically assisted surgery for mitral valve disease is questioned because the high cost of care associated with robotic technology may outweigh its clinical benefits. Objective To investigate conditions under which benefits of robotic surgery mitigate high technology costs. Design Clinical cohort study comparing costs of robotic vs. three contemporaneous conventional surgical approaches for degenerative mitral disease. Surgery was performed from 2006–2011, and comparisons were based on intent-to-treat, with propensity-matching used to reduce selection bias. Setting Large multi-specialty academic medical center. Participants 1,290 patients aged 57±11 years, 27% women, underwent mitral repair for regurgitation from posterior leaflet prolapse. Robotic surgery was used in 473, complete sternotomy in 227, partial sternotomy in 349, and anterolateral thoracotomy in 241. Three propensity-matched groups were formed based on demographics, symptoms, cardiac and noncardiac comorbidities, valve pathophysiology, and echocardiographic measurements: robotic vs. sternotomy (n=198 pairs) vs. partial sternotomy (n=293 pairs) vs. thoracotomy (n=224 pairs). Interventions Mitral valve repair. Main Outcome Measures Cost of care, expressed as robotic capital investment, maintenance, and direct technical hospital cost, and benefit of care, based on differences in recovery time. Results Median cost of care for robotically assisted surgery exceeded the cost of alternative approaches by 27% (−5%, 68%), 32% (−6%, 70%), and 21% (−2%, 54%) (median [15th, 85th percentiles]) for complete sternotomy, partial sternotomy, and anterolateral thoracotomy, respectively. Higher operative costs were partially offset by lower postoperative costs and earlier return to work: median 35 days for robotic surgery, 49 for complete sternotomy, 56 for partial sternotomy, and 42 for anterolateral thoracotomy. Resulting net differences in cost of robotic surgery vs. the three

  8. [Postoperative acute mitral regurgitation. Unexpected finding after minor non-cardiac surgery].

    PubMed

    Wagner, K J; Unterbuchner, C; Bogdanski, R; Martin, J; Kochs, E F; Tassani-Prell, P

    2008-10-01

    This report describes the case of a 59-year-old man who was scheduled for general anesthesia with propofol, sufentanil and sevoflurane for removal of a metal implant. The patient was classified as American Society of Anesthesiologists (ASA) II status because of an asymptomatic mitral valve prolapse and medically treated arterial hypertension. During induction of narcosis a pulsoxymetrically measured inadequate increase in oxygen saturation after preoxygenation was noticed and a moderate respiratory obstruction occurred intraoperatively, but anesthesia was uneventfully completed and the patient was extubated. However, 3 h later the patient developed severe dyspnea, hypoxia, tachycardia and arterial hypotension. Physical examination revealed a new grade 4/6 systolic murmur radiating to the axilla and X-ray showed bilateral pulmonary edema. Neither electrocardiographic nor biochemical manifestations of acute myocardial infarction were identified but transthoracic echocardiography revealed fluttering of the posterior leaflet of the mitral valve with grade III regurgitation and dilation of the left atrium. Coronary angiography was normal and left ventriculography confirmed severe mitral regurgitation. Mitral valve repair was successfully performed 22 h after presentation of symptoms. Mitral regurgitation is a common finding on echocardiography, seen to some degree in over 75% of the population. The etiology of mitral valve insufficiency which can be caused by pathologic changes of one or more of the components of the mitral valve, including the leaflets, annulus, chordae tendineae, papillary muscles, or by abnormalities of the surrounding left ventricle and/or atrium are discussed. Rupture of mitral chordae tendineae is infrequent and causes acute hemodynamic deterioration and needs corrective surgery. Valve replacement should be performed only if mitral valve repair is not possible. Echocardiography is an invaluable tool in determining the severity of regurgitation

  9. Pathogenesis of optic disc edema in raised intracranial pressure.

    PubMed

    Hayreh, Sohan Singh

    2016-01-01

    raised CSFP in patients, by evaluating optic disc and fundus changes by stereoscopic fundus photography and fluorescein fundus angiography. Based on the combined information from all the studies discussed above, it is clear that the pathogenesis of optic disc edema in raised intracranial pressure is a mechanical phenomenon. It is primarily due to a rise of CSFP in the optic nerve sheath, which produces axoplasmic flow stasis in the optic nerve fibers in the surface nerve fiber layer and prelaminar region of the optic nerve head. Axoplasmic flow stasis then results in swelling of the nerve fibers, and consequently of the optic disc. Swelling of the nerve fibers and of the optic disc secondarily compresses the fine, low-pressure venules in that region, resulting in venous stasis and fluid leakage; that leads to the accumulation of extracellular fluid. Contrary to the previous theories, the various vascular changes seen in optic disc edema are secondary and not primary. Thus, optic disc edema in raised CSFP is due to a combination of swollen nerve fibers and the accumulation of extracellular fluid. My studies also provided information about the pathogeneses of visual disturbances in raised intracranial pressure.

  10. PATHOGENESIS OF OPTIC DISC EDEMA IN RAISED INTRACRANIAL PRESSURE

    PubMed Central

    Hayreh, Sohan Singh

    2015-01-01

    raised CSFP in patients, by evaluating optic disc and fundus changes by stereoscopic fundus photography and fluorescein fundus angiography. Based on the combined information from all the studies discussed above, it is clear that the pathogenesis of optic disc edema in raised intracranial pressure is a mechanical phenomenon. It is primarily due to a rise of CSFP in the optic nerve sheath, which produces axoplasmic flow stasis in the optic nerve fibers in the surface nerve fiber layer and prelaminar region of the optic nerve head. Axoplasmic flow stasis then results in swelling of the nerve fibers, and consequently of the optic disc. Swelling of the nerve fibers and of the optic disc secondarily compresses the fine, low-pressure venules in that region, resulting in venous stasis and fluid leakage; that leads to the accumulation of extracellular fluid. Contrary to the previous theories, the various vascular changes seen in optic disc edema are secondary and not primary. Thus, optic disc edema in raised CSFP is due to a combination of swollen nerve fibers and the accumulation of extracellular fluid. My studies also provided information about the pathogeneses of visual disturbances in raised intracranial pressure. PMID:26453995

  11. Genetic Factors in Intervertebral Disc Degeneration

    PubMed Central

    Feng, Yi; Egan, Brian; Wang, Jinxi

    2016-01-01

    Low back pain (LBP) is a major cause of disability and imposes huge economic burdens on human society worldwide. Among many factors responsible for LBP, intervertebral disc degeneration (IDD) is the most common disorder and is a target for intervention. The etiology of IDD is complex and its mechanism is still not completely understood. Many factors such as aging, spine deformities and diseases, spine injuries, and genetic factors are involved in the pathogenesis of IDD. In this review, we will focus on the recent advances in studies on the most promising and extensively examined genetic factors associated with IDD in humans. A number of genetic defects have been correlated with structural and functional changes within the intervertebral disc (IVD), which may compromise the disc’s mechanical properties and metabolic activities. These genetic and proteomic studies have begun to shed light on the molecular basis of IDD, suggesting that genetic factors are important contributors to the onset and progression of IDD. By continuing to improve our understanding of the molecular mechanisms of IDD, specific early diagnosis and more effective treatments for this disabling disease will be possible in the future. PMID:27617275

  12. Gravitoturbulence in magnetized protostellar discs

    NASA Astrophysics Data System (ADS)

    Riols, A.; Latter, H.

    2016-08-01

    Gravitational instability (GI) features in several aspects of protostellar disc evolution, most notably in angular momentum transport, fragmentation, and the outbursts exemplified by FU Ori and EX Lupi systems. The outer regions of protostellar discs may also be coupled to magnetic fields, which could then modify the development of GI. To understand the basic elements of their interaction, we perform local 2D ideal and resistive magnetohydrodynamics simulations with an imposed toroidal field. In the regime of moderate plasma beta, we find that the system supports a hot gravitoturbulent state, characterized by considerable magnetic energy and stress and a surprisingly large Toomre parameter Q ≳ 10. This result has potential implications for disc structure, vertical thickness, ionization, etc. Our simulations also reveal the existence of long-lived and dense `magnetic islands' or plasmoids. Lastly, we find that the presence of a magnetic field has little impact on the fragmentation criterion of the disc. Though our focus is on protostellar discs, some of our results may be relevant for the outer radii of AGN.

  13. Optimizing the exposure in minimally invasive mitral surgery: a new left atrial retractor system

    PubMed Central

    Rose, David; Irace, Francesco; Frati, Giacomo

    2016-01-01

    Optimal exposure of the mitral valve is paramount in minimally invasive surgery (MIS) and a prerequisite for successful mitral valve repair or replacement. We report the concept of a new left atrial retractor (Karl Storz GmbH, Tuttlingen, Germany) dedicated to MIS. The effectiveness of the device was evaluated in a prospective series of 40 patients successfully operated at our institution. PMID:28149570

  14. Spontaneous rupture of a caseous calcification of the mitral annulus in a hemodialysis patient.

    PubMed

    Hamasaki, Azumi; Uchida, Tetsuro; Sadahiro, Mitsuaki

    2017-02-01

    We report a 56-year-old hemodialysis patient with a spontaneously ruptured caseous calcification of the mitral annulus resulting in multiple cerebral emboli. The mass was resected without replacing the mitral valve. The patient has remained symptom-free 3.5 years following surgery.

  15. A Genomics-Based Model for Prediction of Severe Bioprosthetic Mitral Valve Calcification

    PubMed Central

    Ponasenko, Anastasia V.; Khutornaya, Maria V.; Kutikhin, Anton G.; Rutkovskaya, Natalia V.; Tsepokina, Anna V.; Kondyukova, Natalia V.; Yuzhalin, Arseniy E.; Barbarash, Leonid S.

    2016-01-01

    Severe bioprosthetic mitral valve calcification is a significant problem in cardiovascular surgery. Unfortunately, clinical markers did not demonstrate efficacy in prediction of severe bioprosthetic mitral valve calcification. Here, we examined whether a genomics-based approach is efficient in predicting the risk of severe bioprosthetic mitral valve calcification. A total of 124 consecutive Russian patients who underwent mitral valve replacement surgery were recruited. We investigated the associations of the inherited variation in innate immunity, lipid metabolism and calcium metabolism genes with severe bioprosthetic mitral valve calcification. Genotyping was conducted utilizing the TaqMan assay. Eight gene polymorphisms were significantly associated with severe bioprosthetic mitral valve calcification and were therefore included into stepwise logistic regression which identified male gender, the T/T genotype of the rs3775073 polymorphism within the TLR6 gene, the C/T genotype of the rs2229238 polymorphism within the IL6R gene, and the A/A genotype of the rs10455872 polymorphism within the LPA gene as independent predictors of severe bioprosthetic mitral valve calcification. The developed genomics-based model had fair predictive value with area under the receiver operating characteristic (ROC) curve of 0.73. In conclusion, our genomics-based approach is efficient for the prediction of severe bioprosthetic mitral valve calcification. PMID:27589735

  16. A Genomics-Based Model for Prediction of Severe Bioprosthetic Mitral Valve Calcification.

    PubMed

    Ponasenko, Anastasia V; Khutornaya, Maria V; Kutikhin, Anton G; Rutkovskaya, Natalia V; Tsepokina, Anna V; Kondyukova, Natalia V; Yuzhalin, Arseniy E; Barbarash, Leonid S

    2016-08-31

    Severe bioprosthetic mitral valve calcification is a significant problem in cardiovascular surgery. Unfortunately, clinical markers did not demonstrate efficacy in prediction of severe bioprosthetic mitral valve calcification. Here, we examined whether a genomics-based approach is efficient in predicting the risk of severe bioprosthetic mitral valve calcification. A total of 124 consecutive Russian patients who underwent mitral valve replacement surgery were recruited. We investigated the associations of the inherited variation in innate immunity, lipid metabolism and calcium metabolism genes with severe bioprosthetic mitral valve calcification. Genotyping was conducted utilizing the TaqMan assay. Eight gene polymorphisms were significantly associated with severe bioprosthetic mitral valve calcification and were therefore included into stepwise logistic regression which identified male gender, the T/T genotype of the rs3775073 polymorphism within the TLR6 gene, the C/T genotype of the rs2229238 polymorphism within the IL6R gene, and the A/A genotype of the rs10455872 polymorphism within the LPA gene as independent predictors of severe bioprosthetic mitral valve calcification. The developed genomics-based model had fair predictive value with area under the receiver operating characteristic (ROC) curve of 0.73. In conclusion, our genomics-based approach is efficient for the prediction of severe bioprosthetic mitral valve calcification.

  17. The "Polar Light Sign" is a useful tool to detect discrete membranous supravalvular mitral stenosis.

    PubMed

    Hertwig, Christine; Haas, Nikolaus A; Habash, Sheeraz; Hanslik, Andreas; Kececioglu, Deniz; Sandica, Eugen; Laser, Kai-Thorsten

    2015-02-01

    Mitral valve stenosis caused by a discrete supravalvular membrane is a rare congenital malformation haemodynamically leading to significant mitral valve stenosis. When the supravalvular mitral stenosis consists of a discrete supravalvular membrane adherent to the mitral valve, it is usually not clearly detectable by routine echocardiography. We report about the typical echocardiographic finding in three young patients with this rare form of a discrete membranous supravalvular stenosis caused by a membrane adherent to the mitral valve. These cases present a typical echocardiographic feature in colour Doppler generated by the pathognomonic supramitral flow acceleration. Whereas typical supravalvular mitral stenosis caused by cor triatriatum or a clearly visible supravalvular ring is easily detectable by echocardiography, a discrete supravalvular membrane adjacent to the mitral valve leaflets resembling valvular mitral stenosis is difficult to differentiate by routine echocardiography. In our opinion, this colour phenomenon does resemble the visual impression of polar lights in the northern hemisphere; owing to its typical appearance, it may therefore be named as "Polar Light Sign". This phenomenon may help to detect this anatomical entity by echocardiography in time and therefore improve the prognosis for repair.

  18. Repair or replace for severe ischemic mitral regurgitation: prospective randomized multicenter data.

    PubMed

    LaPar, Damien J; Acker, Michael A; Gelijns, Annetine C; Kron, Irving L

    2015-09-01

    Ischemic mitral regurgitation (IMR) is a subset of functional mitral regurgitation (MR) that has the potential to impact an increasing number of patients in the future. This is in the context of a worldwide population, which continues to live longer with improved survival after myocardial infarction. Substantial data have accumulated over the past few decades demonstrating the negative effects of IMR. Further, significant research has been done to define the optimal surgical approach and several studies have compared mitral repair versus replacement for patients with severe mitral regurgitation (SMR). Studies supporting performance of mitral repair cite superior operative morbidity and mortality rates, while proponents of mitral replacement cite improved long-term durability and correction of MR. Lack of clinically robust Level I randomized controlled trial data have curtailed attempts to better define appropriate surgical treatment allocation over the past few decades. Recently, however, the Cardiothoracic Surgical Trials Network (CTSN) conducted the first randomized controlled trial, funded by the National Heart, Lung, and Blood Institute, the National Institute for Neurological Diseases and Stroke and the Canadian Institute for Health Research, to compare the performance of mitral repair versus replacement for SMR. Herein, the present review describes the design, results and implications of the CTSN SMR trial and its efforts to identify the most efficacious surgical approach to SMR. This review also describes CTSN investigation to predict the recurrence of MR after mitral repair.

  19. Subacute Staphylococcus epidermidis Bacterial Endocarditis Complicated by Mitral-Aortic Intervalvular Fibrosa Pseudoaneurysm

    DTIC Science & Technology

    2012-12-01

    Staphylococcus epidermidis Bacterial Endocarditis Complicated byMitral- Aortic Intervalvular Fibrosa Pseudoaneurysm Diane Elegino-Steffens,1 Amy Stratton,1...hypertension and congestive heart failure who underwent a bioprosthetic aortic valve replacement secondary to acute onset of aortic insufficiency...severe regurgitation, anterior and posterior leaflet vegetations, and scallop prolapse. There was also evidence of a mitral- aortic intervalvular fibrosa

  20. Aortic valve replacement with the Nicks annulus enlargement procedure 12 years after mitral valve replacement.

    PubMed

    Kazama, S; Kurata, A; Yamashita, Y

    1999-10-01

    An aortic valve replacement was successfully performed employing the Nicks annulus enlargement procedure in a case of aortic valve stenosis with small annulus 12 years after mitral valve replacement. Previous mitral valve replacement does not preclude feasibility of the Nicks procedure.

  1. Papillary muscle insertion directly into the anterior mitral leaflet in hypertrophic cardiomyopathy, its identification and cause of outflow obstruction by cardiac magnetic resonance imaging, and its surgical management.

    PubMed

    Rowin, Ethan J; Maron, Barry J; Lesser, John R; Rastegar, Hassan; Maron, Martin S

    2013-06-01

    This case presents an uncommon but important mechanism of muscular left ventricular outflow obstruction in hypertrophic cardiomyopathy due to anomalous and direct papillary muscle insertion into the anterior mitral leaflet, a finding reliably identified clinically by cardiac magnetic resonance imaging. The identification of this left ventricular outflow tract morphology is important before invasive ventricular septal reduction therapy because it dictates a specific surgical strategy. These findings further support the role of cardiac magnetic resonance imaging in the early evaluation of hypertrophic cardiomyopathy patients.

  2. [Sudden and fatal malfunction of a Björk-Shiley prosthesis in mitral position due to rupture of the ventricular bracket and disk embolization].

    PubMed

    Casarotto, D; Motta, A; Fabbri, A; Pugliese, P; Muneretto, C; Zanini, M; Sheiban, I

    1985-04-01

    Mechanical complications of prosthetic valves are increasing. The following report describes a case of fracture of a Björk-Shiley mitral prosthetic strut with dislogment of the valve occluder into the thoracic aorta. At the reoperation a new prosthesis was implanted but the patient died of acute heart failure. The diagnosis of valve disfunction must be made non invasively, because the time required for cardiac catherization usually constitutes a lethal delay. The only hope for survival is prompt surgical treatment.

  3. Intervertebral Disc Degeneration and Ectopic Bone Formation in Apolipoprotein E Knockout Mice

    PubMed Central

    Zhang, Dawei; Jin, Li; Reames, Davis L.; Shen, Francis H.; Shimer, Adam L.; Li, Xudong

    2012-01-01

    Cardiovascular risk factors are known to be associated with intervertebral disc degeneration, but the underlying mechanism is still unclear. ApoE knockout (KO) mouse is a well-established model for arthrosclerosis. We hypothesize that ApoE may involve in maintaining disc health and ApoE KO mouse develops early disc degeneration. Discs of ApoE KO and wild-type (WT) mice were characterized with histological/immunological, biochemical, and real time RT-PCR assays. A comparison of the extracellular matrix production was also performed in disc cells. We demonstrated that ApoE was highly expressed in the endplates of WT discs and ectopic bone formed in the endplates of ApoE KO discs. Glycosaminoglycan content was decreased in both ApoE KO annulus fibrosus (AF) and nucleus pulpsous (NP) cells. Collagen levels were increased in AF and decreased in NP cells. Matrix metalloproteinases-3, 9, and 13 expression was increased which may partially explain the impaired matrix production. We also found increased collagen I, II, aggrecan and biglycan mRNA expressions in AF cells but decreased in NP cells. Apoptosis was increased in the ApoE KO NP tissue. These results suggest early disc degeneration changes in ApoE KO mice. ApoE, plus its importance to cardiovascular disease, may play a critical role in disc integrity and function. PMID:22915292

  4. Atomic gas in debris discs

    NASA Astrophysics Data System (ADS)

    Hales, Antonio S.; Barlow, M. J.; Crawford, I. A.; Casassus, S.

    2017-04-01

    We have conducted a search for optical circumstellar absorption lines in the spectra of 16 debris disc host stars. None of the stars in our sample showed signs of emission line activity in either Hα, Ca II or Na I, confirming their more evolved nature. Four stars were found to exhibit narrow absorption features near the cores of the photospheric Ca II and Na I D lines (when Na I D data were available). We analyse the characteristics of these spectral features to determine whether they are of circumstellar or interstellar origins. The strongest evidence for circumstellar gas is seen in the spectrum of HD 110058, which is known to host a debris disc observed close to edge-on. This is consistent with a recent ALMA detection of molecular gas in this debris disc, which shows many similarities to the β Pictoris system.

  5. Coevolution of binaries and circumbinary gaseous discs

    NASA Astrophysics Data System (ADS)

    Fleming, David P.; Quinn, Thomas R.

    2017-01-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc which drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for 104 binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentric binaries which strongly couple to the disc develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance which corresponds to an alignment of gas particle longitude of periastrons. All systems display binary semimajor axis decay due to dissipation from the viscous disc.

  6. The activL® Artificial Disc: a next-generation motion-preserving implant for chronic lumbar discogenic pain

    PubMed Central

    Yue, James J; Garcia, Rolando; Miller, Larry E

    2016-01-01

    Degeneration of the lumbar intervertebral discs is a leading cause of chronic low back pain in adults. Treatment options for patients with chronic lumbar discogenic pain unresponsive to conservative management include total disc replacement (TDR) or lumbar fusion. Until recently, only two lumbar TDRs had been approved by the US Food and Drug Administration − the Charité Artificial Disc in 2004 and the ProDisc-L Total Disc Replacement in 2006. In June 2015, a next-generation lumbar TDR received Food and Drug Administration approval − the activL® Artificial Disc (Aesculap Implant Systems). Compared to previous-generation lumbar TDRs, the activL® Artificial Disc incorporates specific design enhancements that result in a more precise anatomical match and allow a range of motion that better mimics the healthy spine. The results of mechanical and clinical studies demonstrate that the activL® Artificial Disc results in improved mechanical and clinical outcomes versus earlier-generation artificial discs and compares favorably to lumbar fusion. The purpose of this report is to describe the activL® Artificial Disc including implant characteristics, intended use, surgical technique, postoperative care, mechanical testing, and clinical experience to date. PMID:27274317

  7. The activL(®) Artificial Disc: a next-generation motion-preserving implant for chronic lumbar discogenic pain.

    PubMed

    Yue, James J; Garcia, Rolando; Miller, Larry E

    2016-01-01

    Degeneration of the lumbar intervertebral discs is a leading cause of chronic low back pain in adults. Treatment options for patients with chronic lumbar discogenic pain unresponsive to conservative management include total disc replacement (TDR) or lumbar fusion. Until recently, only two lumbar TDRs had been approved by the US Food and Drug Administration - the Charité Artificial Disc in 2004 and the ProDisc-L Total Disc Replacement in 2006. In June 2015, a next-generation lumbar TDR received Food and Drug Administration approval - the activL(®) Artificial Disc (Aesculap Implant Systems). Compared to previous-generation lumbar TDRs, the activL(®) Artificial Disc incorporates specific design enhancements that result in a more precise anatomical match and allow a range of motion that better mimics the healthy spine. The results of mechanical and clinical studies demonstrate that the activL(®) Artificial Disc results in improved mechanical and clinical outcomes versus earlier-generation artificial discs and compares favorably to lumbar fusion. The purpose of this report is to describe the activL(®) Artificial Disc including implant characteristics, intended use, surgical technique, postoperative care, mechanical testing, and clinical experience to date.

  8. Percutaenous mitral valve: A non-stented coronary sinus device for the treatment of functional mitral regurgitation in heart failure patients.

    PubMed

    Sack, Stefan; Kahlert, Philipp; Erbel, Raimund

    2009-01-01

    Functional mitral regurgitation in heart failure limits survival in a severity-graded fashion. Even mild mitral regurgitation doubles mortality risk. We report the use of a non-stented coronary sinus device to reduce mitral annulus dimension in order to re-establish mitral valve competence. The device (PTMA, Viacor, Inc., Wilmington, MA, USA) consists of a multi-lumen PTFE (Teflon) PTMA catheter in which Nitinol (nickel-titanium alloy) treatment rods are advanced. For individual use up to three rods of different length and stiffness can be used. Therefore dimension reduction can be performed in an incremental fashion. Fluoroscopy and 3 D echocardiography are performed throughout the procedure to visiualize the positioning and confirm maximum treatment effect. The case describes the use and the effect of PTMA treatment. Safety and efficacy of the PTMA device will be investigated in the upcoming PTOLEMY 2 trial.

  9. The Mitral Valve in Obstructive Hypertrophic Cardiomyopathy: A Test in Context.

    PubMed

    Sherrid, Mark V; Balaram, Sandhya; Kim, Bette; Axel, Leon; Swistel, Daniel G

    2016-04-19

    Mitral valve abnormalities were not part of modern pathological and clinical descriptions of hypertrophic cardiomyopathy in the 1950s, which focused on left ventricular (LV) hypertrophy and myocyte fiber disarray. Although systolic anterior motion (SAM) of the mitral valve was discovered as the cause of LV outflow tract obstruction in the M-mode echocardiography era, in the 1990s structural abnormalities of the mitral valve became appreciated as contributing to SAM pathophysiology. Hypertrophic cardiomyopathy mitral malformations have been identified at all levels. They occur in the leaflets, usually elongating them, and also in the submitral apparatus, with a wide array of malformations of the papillary muscles and chordae, that can be detected by transthoracic and transesophageal echocardiography and by cardiac magnetic resonance. Because they participate fundamentally in the predisposition to SAM, they have increasingly been repaired surgically. This review critically assesses imaging and measurement of mitral abnormalities and discusses their surgical relief.

  10. Incremental value of 3-D transesophageal echocardiographic imaging of the mitral valve.

    PubMed

    Jain, Sonia; Malouf, Joseph F

    2014-01-01

    Transesophageal echocardiography provides excellent visualization of the posteriorly located mitral valve. Over the last decade, 3-dimensional transesophageal echocardiography (3D TEE) has emerged as an exciting imaging modality, particularly of the mitral valve. The current generation matrix array technology allows the operator to perform 2D and 3D imaging with a single transducer. 3D TEE affords the unique ability to view the mitral valve and its surrounding structures "en face" in real time (RT), and provide contextual anatomical guidance during surgical and transcatheter interventions. Additionally, offline quantification has made significant contributions to our mechanistic understanding of the normal and diseased mitral valve, and alterations induced by therapeutic intervention such as surgical repair. This review will address recent advances in the incremental role of 3D TEE in mitral valve imaging.

  11. Mitral Repair Is Superior to Replacement When Associated With Coronary Artery Disease

    PubMed Central

    Reece, T Brett; Tribble, Curtis G.; Ellman, Peter I.; Maxey, Thomas S.; Woodford, Randall L.; Dimeling, George M.; Wellons, Harry A.; Crosby, Ivan K.; Kern, John A.; Kron, Irving L.

    2004-01-01

    Objective: To compare the outcomes of mitral repair and replacement in revascularized patients with ischemic mitral regurgitation. Summary Background Data: Combined coronary bypass (CABG) and mitral procedures have been associated with the highest mortality (>10%) in cardiac surgery. Recent studies have suggested that mitral valve replacement (MVR) with sparing of the subvalvular apparatus had comparable results to mitral repair when associated with CABG. Methods: Over the past 7 years, 54 patients had CABG/mitral repair versus 56 who had CABG/MVR with preservation of the subvalvular apparatus. The groups were similar in age at 69.2 years in the replacement group versus 67.0 in the repair group. We compared these 2 groups based on hospital mortality, incidence of complications including nosocomial infection, neurologic decompensation (stroke), pulmonary complication (pneumonia, atelectasis, and prolonged ventilation), and renal complications (acute renal failure or insufficiency). Results: The mitral repair group had a hospital mortality of 1.9% versus 10.7% in the replacement group (P = 0.05). Infection occurred in 9% of repairs compared with 13% of replacements (P = 0.59). The incidence of stroke was no different between groups (2 of 54 repairs vs. 2 of 56 replacements, P = 1.00). Pulmonary complication rate was 39% in repairs versus 32% in replacements (P = 0.59). Worsening renal function occurred in 15% of repairs versus 18% of replacements (P = 0.67). Conclusions: Mitral repair is superior to mitral replacement when associated with coronary artery disease in terms of perioperative morbidity and hospital mortality. Although preservation of the subvalvular apparatus with MVR has a theoretical advantage in terms of ventricular function, mitral repair clearly adds a survival benefit in patients with concomitant ischemic cardiac disease. PMID:15082971

  12. Mass transfer between debris discs during close stellar encounters

    NASA Astrophysics Data System (ADS)

    Jílková, Lucie; Hamers, Adrian S.; Hammer, Michael; Portegies Zwart, Simon

    2016-04-01

    We study mass transfers between debris discs during stellar encounters. We carried out numerical simulations of close flybys of two stars, one of which has a disc of planetesimals represented by test particles. We explored the parameter space of the encounters, varying the mass ratio of the two stars, their pericentre and eccentricity of the encounter, and its geometry. We find that particles are transferred to the other star from a restricted radial range in the disc and the limiting radii of this transfer region depend on the parameters of the encounter. We derive an approximate analytic description of the inner radius of the region. The efficiency of the mass transfer generally decreases with increasing encounter pericentre and increasing mass of the star initially possessing the disc. Depending on the parameters of the encounter, the transfer particles have a specific distribution in the space of orbital elements (semimajor axis, eccentricity, inclination, and argument of pericentre) around their new host star. The population of the transferred particles can be used to constrain the encounter through which it was delivered. We expect that many stars experienced transfer among their debris discs and planetary systems in their birth environment. This mechanism presents a formation channel for objects on wide orbits of arbitrary inclinations, typically having high eccentricity but possibly also close to circular (eccentricities of about 0.1). Depending on the geometry, such orbital elements can be distinct from those of the objects formed around the star.

  13. Advancing the cellular and molecular therapy for intervertebral disc disease.

    PubMed

    Sakai, Daisuke; Grad, Sibylle

    2015-04-01

    The healthy intervertebral disc (IVD) fulfils the essential function of load absorption, while maintaining multi-axial flexibility of the spine. The interrelated tissues of the IVD, the annulus fibrosus, the nucleus pulposus, and the cartilaginous endplate, are characterised by their specific niche, implying avascularity, hypoxia, acidic environment, low nutrition, and low cellularity. Anabolic and catabolic factors balance a slow physiological turnover of extracellular matrix synthesis and breakdown. Deviations in mechanical load, nutrient supply, cellular activity, matrix composition and metabolism may initiate a cascade ultimately leading to tissue dehydration, fibrosis, nerve and vessel ingrowth, disc height loss and disc herniation. Spinal instability, inflammation and neural sensitisation are sources of back pain, a worldwide leading burden that is challenging to cure. In this review, advances in cell and molecular therapy, including mobilisation and activation of endogenous progenitor cells, progenitor cell homing, and targeted delivery of cells, genes, or bioactive factors are discussed.

  14. Percutaneous Transcatheter Aortic Disc Valve Prosthesis Implantation: A Feasibility Study

    SciTech Connect

    Sochman, Jan

    2000-09-15

    Purpose: Over the past 30 years there have been experimental efforts at catheter-based management of aortic valve regurgitation with the idea of extending treatment to nonsurgical candidates. A new catheter-based aortic valve design is described.Methods: The new catheter-delivered valve consists of a stent-based valve cage with locking mechanism and a prosthetic flexible tilting valve disc. The valve cage is delivered first followed by deployment and locking of the disc. In acute experiments, valve implantation was done in four dogs.Results: Valve implantation was successful in all four animals. The implanted valve functioned well for the duration of the experiments (up to 3 hr).Conclusion: The study showed the implantation feasibility and short-term function of the tested catheter-based aortic disc valve. Further experimental studies are warranted.

  15. Pulsed Doppler echocardiographic analysis of mitral regurgitation after myocardial infarction.

    PubMed

    Loperfido, F; Biasucci, L M; Pennestri, F; Laurenzi, F; Gimigliano, F; Vigna, C; Rossi, E; Favuzzi, A; Santarelli, P; Manzoli, U

    1986-10-01

    In 72 patients with previous myocardial infarction (MI), mitral regurgitation (MR) was assessed by pulsed-wave Doppler echocardiography and compared with physical and 2-dimensional echocardiographic findings. MR was found by Doppler in 29 of 42 patients (62%) with anterior MI, 11 of 30 (37%) with inferior MI (p less than 0.01) and in none of 20 normal control subjects. MR was more frequent in patients who underwent Doppler study 3 months after MI than in those who underwent Doppler at discharge (anterior MI = 83% vs 50%, p less than 0.01; inferior MI = 47% vs 27%, p = not significant). Of 15 patients who underwent Doppler studies both times, 3 (all with anterior MI) had MR only on the second study. Of the patients with Doppler MR, 12 of 27 (44%) with a left ventricular (LV) ejection fraction (EF) greater than 30% and 1 of 13 (8%) with an EF of 30% or less (p less than 0.01) had an MR systolic murmur. Mitral prolapse or eversion and papillary muscle fibrosis were infrequent in MI patients, whether or not Doppler MR was present. The degree of Doppler MR correlated with EF (r = -0.61), LV systolic volume (r = 0.47), and systolic and diastolic mitral anulus circumference (r = 0.52 and 0.51, respectively). Doppler MR was present in 24 of 28 patients (86%) with an EF of 40% or less and in 16 of 44 (36%) with EF more than 40% (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Normal echocardiographic mitral and aortic valve thickness in children

    PubMed Central

    Webb, Rachel H; Culliford-Semmens, Nicola; Sidhu, Karishma; Wilson, Nigel J

    2017-01-01

    Objective We aimed to define the normal range of aortic and mitral valve thickness in healthy schoolchildren from a high prevalence rheumatic heart disease (RHD) region, using a standardised protocol for imaging and measurement. Methods Measurements were performed in 288 children without RHD. Anterior mitral valve leaflet (AMVL) thickness measurements were performed at the midpoint and tip of the leaflet in the parasternal long axis (PSLA) in diastole, when the AMVL was approximately parallel to the ventricular septum. Thickness of the aortic valve was measured from PSLA imaging in systole when the leaflets were at maximum excursion. The right coronary and non-coronary closure lines of the aortic valve were measured in diastole in parasternal short axis (PSSA) imaging. Results were compared with 51 children with RHD classified by World Heart Federation diagnostic criteria. Results In normal children, median AMVL tip thickness was 2.0 mm (IQR 1.7–2.4) and median AMVL midpoint thickness 2.0 mm (IQR 1.7–2.4). The median aortic valve thickness was 1.5 mm (IQR 1.3–1.6) in the PSLA view and 1.4 mm (IQR 1.2–1.6) in the PSSA view. The interclass correlation coefficient for the AMVL tip was 0.85 (0.71 to 0.92) and for the AMVL midpoint was 0.77 (0.54 to 0.87). Conclusions We have described a standardised method for mitral and aortic valve measurement in children which is objective and reproducible. Normal ranges of left heart valve thickness in a high prevalence RHD population are established. These results provide a reference range for school-age children in high prevalence RHD regions undergoing echocardiographic screening.

  17. Cognitive tools pipeline for assistance of mitral valve surgery

    NASA Astrophysics Data System (ADS)

    Schoch, Nicolai; Philipp, Patrick; Weller, Tobias; Engelhardt, Sandy; Volovyk, Mykola; Fetzer, Andreas; Nolden, Marco; De Simone, Raffaele; Wolf, Ivo; Maleshkova, Maria; Rettinger, Achim; Studer, Rudi; Heuveline, Vincent

    2016-03-01

    For cardiac surgeons, mitral valve reconstruction (MVR) surgery is a highly demanding procedure, where an artificial annuloplasty ring is implanted onto the mitral valve annulus to re-enable the valve's proper closing functionality. For a successful operation the surgeon has to keep track of a variety of relevant impact factors, such as patient-individual medical history records, valve geometries, or tissue properties of the surgical target, and thereon-based deduce type and size of the best-suitable ring prosthesis according to practical surgery experience. With this work, we aim at supporting the surgeon in selecting this ring prosthesis by means of a comprehensive information processing pipeline. It gathers all available patient-individual information, and mines this data according to 'surgical rules', that represent published MVR expert knowledge and recommended best practices, in order to suggest a set of potentially suitable annuloplasty rings. Subsequently, these rings are employed in biomechanical MVR simulation scenarios, which simulate the behavior of the patient-specific mitral valve subjected to the respective virtual ring implantation. We present the implementation of our deductive system for MVR ring selection and how it is integrated into a cognitive data processing pipeline architecture, which is built under consideration of Linked Data principles in order to facilitate holistic information processing of heterogeneous medical data. By the example of MVR surgery, we demonstrate the ease of use and the applicability of our development. We expect to essentially support patient-specific decision making in MVR surgery by means of this holistic information processing approach.

  18. Role of Mitral Annulus Diastolic Geometry on Intraventricular Filling Dynamics

    PubMed Central

    Okafor, Ikechukwu U.; Santhanakrishnan, Arvind; Raghav, Vrishank S.; Yoganathan, Ajit P.

    2015-01-01

    The mitral valve (MV) is a bileaflet valve positioned between the left atrium and ventricle of the heart. The annulus of the MV has been observed to undergo geometric changes during the cardiac cycle, transforming from a saddle D-shape during systole to a flat (and less eccentric) D-shape during diastole. Prosthetic MV devices, including heart valves and annuloplasty rings, are designed based on these two configurations, with the circular design of some prosthetic heart valves (PHVs) being an approximation of the less eccentric, flat D-shape. Characterizing the effects of these geometrical variations on the filling efficiency of the left ventricle (LV) is required to understand why the flat D-shaped annulus is observed in the native MV during diastole in addition to optimizing the design of prosthetic devices. We hypothesize that the D-shaped annulus reduces energy loss during ventricular filling. An experimental left heart simulator (LHS) consisting of a flexible-walled LV physical model was used to characterize the filling efficiency of the two mitral annular geometries. The strength of the dominant vortical structure formed and the energy dissipation rate (EDR) of the measured fields, during the diastolic period of the cardiac cycle, were used as metrics to quantify the filling efficiency. Our results indicated that the O-shaped annulus generates a stronger (25% relative to the D-shaped annulus) vortical structure than that of the D-shaped annulus. It was also found that the O-shaped annulus resulted in higher EDR values throughout the diastolic period of the cardiac cycle. The results support the hypothesis that a D-shaped mitral annulus reduces dissipative energy losses in ventricular filling during diastole and in turn suggests that a symmetric stent design does not provide lower filling efficiency than an equivalent asymmetric design. PMID:26502376

  19. Role of Mitral Annulus Diastolic Geometry on Intraventricular Filling Dynamics.

    PubMed

    Okafor, Ikechukwu U; Santhanakrishnan, Arvind; Raghav, Vrishank S; Yoganathan, Ajit P

    2015-12-01

    The mitral valve (MV) is a bileaflet valve positioned between the left atrium and ventricle of the heart. The annulus of the MV has been observed to undergo geometric changes during the cardiac cycle, transforming from a saddle D-shape during systole to a flat (and less eccentric) D-shape during diastole. Prosthetic MV devices, including heart valves and annuloplasty rings, are designed based on these two configurations, with the circular design of some prosthetic heart valves (PHVs) being an approximation of the less eccentric, flat D-shape. Characterizing the effects of these geometrical variations on the filling efficiency of the left ventricle (LV) is required to understand why the flat D-shaped annulus is observed in the native MV during diastole in addition to optimizing the design of prosthetic devices. We hypothesize that the D-shaped annulus reduces energy loss during ventricular filling. An experimental left heart simulator (LHS) consisting of a flexible-walled LV physical model was used to characterize the filling efficiency of the two mitral annular geometries. The strength of the dominant vortical structure formed and the energy dissipation rate (EDR) of the measured fields, during the diastolic period of the cardiac cycle, were used as metrics to quantify the filling efficiency. Our results indicated that the O-shaped annulus generates a stronger (25% relative to the D-shaped annulus) vortical structure than that of the D-shaped annulus. It was also found that the O-shaped annulus resulted in higher EDR values throughout the diastolic period of the cardiac cycle. The results support the hypothesis that a D-shaped mitral annulus reduces dissipative energy losses in ventricular filling during diastole and in turn suggests that a symmetric stent design does not provide lower filling efficiency than an equivalent asymmetric design.

  20. Simulating the sensitivity of cell nutritive environment to composition changes within the intervertebral disc

    NASA Astrophysics Data System (ADS)

    Wills, C. Ruiz; Malandrino, A.; van Rijsbergen, MM.; Lacroix, D.; Ito, K.; Noailly, J.

    2016-05-01

    Altered nutrition in the intervertebral disc affects cell viability and can generate catabolic cascades contributing to extracellular matrix (ECM) degradation. Such degradation is expected to affect couplings between disc mechanics and nutrition, contributing to accelerate degenerative processes. However, the relation of ECM changes to major biophysical events within the loaded disc remains unclear. A L4-L5 disc finite element model including the nucleus (NP), annulus (AF) and endplates was used and coupled to a transport-cell viability model. Solute concentrations and cell viability were evaluated along the mid-sagittal plane path. A design of experiment (DOE) was performed. DOE parameters corresponded to AF and NP biochemical tissue measurements in discs with different degeneration grades. Cell viability was not affected by any parameter combinations defined. Nonetheless, the initial water content was the parameter that affected the most the solute contents, especially glucose. Calculations showed that altered NP composition could negatively affect AF cell nutrition. Results suggested that AF and NP tissue degeneration are not critical to nutrition-related cell viability at early-stage of disc degeneration. However, small ECM degenerative changes may alter significantly disc nutrition under mechanical loads. Coupling disc mechano-transport simulations and enzyme expression studies could allow identifying spatiotemporal sequences related to tissue catabolism.

  1. Persistent pulmonary artery hypertension in patients undergoing balloon mitral valvotomy

    PubMed Central

    Nair, Krishna Kumar Mohanan; Pillai, Harikrishnan Sivadasan; Titus, Thomas; Varaparambil, Ajitkumar; Sivasankaran, Sivasubramonian; Krishnamoorthy, Kavassery Mahadevan; Namboodiri, Narayanan; Sasidharan, Bijulal; Thajudeen, Anees; Ganapathy, Sanjay; Tharakan, Jaganmohan

    2013-01-01

    Pulmonary artery pressure (PAP) is known to regress after successful balloon mitral valvotomy (BMV). Data of persistent pulmonary artery hypertension (PPAH) following BMV is scarce. We analyzed the clinical, echocardiographic, and hemodynamic data of 701 consecutive patients who have undergone successful BMV in our institute from 1997 to 2003. Data of 287 patients who had PPAH (defined by pulmonary artery systolic pressure [PASP] of ≥ 40 mmHg at one year following BMV) were compared to the data of 414 patients who did not have PPAH. Patients who had PPAH were older (39.9 ± 9.9 years vs. 29.4 ± 10.1; P < 0.001). They had higher prevalence of atrial fibrillation (AF; 21.9 vs. 12.1%, P < 0.05), moderate or severe pulmonary artery hypertension (PAH) defined as PASP more than 50 mmHg (43.5 vs. 33.8%, P = 0.00), anatomically advanced mitral valve disease as assessed by Wilkin's echocardiographic score > 8 (33.7 vs. 23.2%, P < 0.001), and coexistent aortic valve disease (45.6 vs. 37.9%, P < 0.001) at the baseline. Those patients with PPAH had comparatively lower immediate postprocedural mitral valve area (MVA). On follow-up of more than five years, the occurrence of restenosis (39.3 vs. 10.1%, P = 0.000), new onset heart failure (14% vs. 4%, P < 0.05) and need for reinterventions (9.5% vs. 2.8%, P < 0.05) were higher in the PPAH group. Patients with PPAH were older, sicker, and had advanced rheumatic mitral valve disease. They had higher incidence of restenosis, new onset heart failure, and need for reinterventions on long term follow-up. PPAH represents an advanced stage of rheumatic valve disease and indicates chronicity of the disease, which may be the reason for the poorer prognosis of these patients. Patients with PPAH requires intense and more frequent follow-up. PMID:24015345

  2. Late entrapment of ball and cage valve in mitral position.

    PubMed

    Akbari, Jayesh G; Varma, Praveen K; Gadhinglajkar, Shrinivas V; Neelakandhan, Kurur S

    2006-02-01

    A 32-year-old female underwent mitral valve replacement with total chordal preservation (Miki's technique) using 26 mm (1M) Starr-Edward prosthesis (SEP) in 1988. The patient was in NYHA class-I until 2001. She progressed to NYHA class-III with paroxysmal nocturnal dyspnoea. Transthoracic echocardiogram showed increased prosthetic valve gradient, and cardiac catheterization confirmed the findings. Intraoperatively, the poppet movement in the cage was found to be restricted due to the preserved subvalvular apparatus entrapping the poppet inside the prosthetic valve cage.

  3. Surgical Ablation of Atrial Fibrillation during Mitral-Valve Surgery

    PubMed Central

    Gillinov, A. Marc; Gelijns, Annetine C.; Parides, Michael K.; DeRose, Joseph J.; Moskowitz, Alan J.; Voisine, Pierre; Ailawadi, Gorav; Bouchard, Denis; Smith, Peter K.; Mack, Michael J.; Acker, Michael A.; Mullen, John C.; Rose, Eric A.; Chang, Helena L.; Puskas, John D.; Couderc, Jean-Philippe; Gardner, Timothy J.; Varghese, Robin; Horvath, Keith A.; Bolling, Steven F.; Michler, Robert E.; Geller, Nancy L.; Ascheim, Deborah D.; Miller, Marissa A.; Bagiella, Emilia; Moquete, Ellen G.; Williams, Paula; Taddei-Peters, Wendy C.; O’Gara, Patrick T.; Blackstone, Eugene H.; Argenziano, Michael

    2015-01-01

    Background Among patients undergoing mitral-valve surgery, 30 to 50% present with atrial fibrillation, which is associated with reduced survival and increased risk of stroke. Surgical ablation of atrial fibrillation has been widely adopted, but evidence regarding its safety and effectiveness is limited. Methods We randomly assigned 260 patients with persistent or long-standing persistent atrial fibrillation who required mitral-valve surgery to undergo either surgical ablation (ablation group) or no ablation (control group) during the mitral-valve operation. Patients in the ablation group underwent further randomization to pulmonary-vein isolation or a biatrial maze procedure. All patients underwent closure of the left atrial appendage. The primary end point was freedom from atrial fibrillation at both 6 months and 12 months (as assessed by means of 3-day Holter monitoring). Results More patients in the ablation group than in the control group were free from atrial fibrillation at both 6 and 12 months (63.2% vs. 29.4%, P<0.001). There was no significant difference in the rate of freedom from atrial fibrillation between patients who underwent pulmonary-vein isolation and those who underwent the biatrial maze procedure (61.0% and 66.0%, respectively; P = 0.60). One-year mortality was 6.8% in the ablation group and 8.7% in the control group (hazard ratio with ablation, 0.76; 95% confidence interval, 0.32 to 1.84; P = 0.55). Ablation was associated with more implantations of a permanent pacemaker than was no ablation (21.5 vs. 8.1 per 100 patient-years, P = 0.01). There were no significant between-group differences in major cardiac or cerebrovascular adverse events, overall serious adverse events, or hospital readmissions. Conclusions The addition of atrial fibrillation ablation to mitral-valve surgery significantly increased the rate of freedom from atrial fibrillation at 1 year among patients with persistent or long-standing persistent atrial fibrillation, but the

  4. RVOT mural and mitral valve endocarditis: A case report.

    PubMed

    Jawad, Maadh; Cardozo, Shaun

    2015-01-01

    Mural endocarditis is a very rare condition. This entity involves bacterial growth on cardiac walls. In addition, concomitant valvular endocarditis, along with mural endocarditis, is an extremely rare combination. The diagnosis of mural endocarditis is difficult and requires more advanced cardiac imaging, such as a transesophageal echocardiogram. The differential diagnoses of mural masses include vegetations, thrombi, metastasis, and benign and malignant tumors. We present a rare and unusual case of Methicillin-Resistant Staphylococcus aureus bacteremia with findings of both right ventricular outflow tract mural endocarditis and valvular endocarditis involving the mitral valve.

  5. RVOT mural and mitral valve endocarditis: A case report

    PubMed Central

    Jawad, Maadh; Cardozo, Shaun

    2015-01-01

    Mural endocarditis is a very rare condition. This entity involves bacterial growth on cardiac walls. In addition, concomitant valvular endocarditis, along with mural endocarditis, is an extremely rare combination. The diagnosis of mural endocarditis is difficult and requires more advanced cardiac imaging, such as a transesophageal echocardiogram. The differential diagnoses of mural masses include vegetations, thrombi, metastasis, and benign and malignant tumors. We present a rare and unusual case of Methicillin-Resistant Staphylococcus aureus bacteremia with findings of both right ventricular outflow tract mural endocarditis and valvular endocarditis involving the mitral valve. PMID:26702695

  6. Transareolar Robotic-Assisted Access to the Mitral Valve.

    PubMed

    Musumeci, Francesco; Mariscalco, Giovanni; Ranocchi, Federico; Tosi, Daniele; Persichetti, Paolo

    2015-01-01

    During the past years, a rapid development and refinements of robotic heart valve techniques have led to consider robotic mitral valve (MV) surgery safe, effective, and durable. Robotic MV surgery has proven to be a cost-effective and cost-saving strategy in MV operations, being associated with reduced morbidity and mortality rates. We present a novel video-assisted transareolar approach to access the MV using the da Vinci Si HD telemanipulation system (Intuitive Surgical, Inc, Sunnyvale, CA USA). This technique is effective and reproducible, providing maximum patient satisfaction from both the clinical and cosmetic points of view.

  7. Double triangular resection for a widely prolapsed posterior mitral leaflet†

    PubMed Central

    Sawazaki, Masaru; Tomari, Shiro; Tsunekawa, Tomohiro; Izawa, Naoto

    2013-01-01

    A wide and redundant prolapse of the posterior mitral leaflet in active infective endocarditis cannot be easily repaired. A sliding plasty can be attempted, but the range of annular plication is often too large. Chordal replacement is another option, but is prone to long-term degeneration because the redundant leaflet still exists. Here, we describe a simple resection technique that utilizes only two small triangular resections. The resections are sutured with no need to shorten the annulus. The leaflet tissue between the two triangular resections must be preserved to make an appropriately shaped posterior leaflet. PMID:23223672

  8. Spiral arms and disc stability in the Andromeda galaxy

    NASA Astrophysics Data System (ADS)

    Tenjes, P.; Tuvikene, T.; Tamm, A.; Kipper, R.; Tempel, E.

    2017-03-01

    Aims: Density waves are often considered as the triggering mechanism of star formation in spiral galaxies. Our aim is to study relations between different star formation tracers (stellar UV and near-IR radiation and emission from H i, CO, and cold dust) in the spiral arms of M 31, to calculate stability conditions in the galaxy disc, and to draw conclusions about possible star formation triggering mechanisms. Methods: We selected fourteen spiral arm segments from the de-projected data maps and compared emission distributions along the cross sections of the segments in different datasets to each other, in order to detect spatial offsets between young stellar populations and the star-forming medium. By using the disc stability condition as a function of perturbation wavelength and distance from the galaxy centre, we calculated the effective disc stability parameters and the least stable wavelengths at different distances. For this we used a mass distribution model of M 31 with four disc components (old and young stellar discs, cold and warm gaseous discs) embedded within the external potential of the bulge, the stellar halo, and the dark matter halo. Each component is considered to have a realistic finite thickness. Results: No systematic offsets between the observed UV and CO/far-IR emission across the spiral segments are detected. The calculated effective stability parameter has a lowest value of Qeff ≃ 1.8 at galactocentric distances of 12-13 kpc. The least stable wavelengths are rather long, with the lowest values starting from ≃ 3 kpc at distances R > 11 kpc. Conclusions: The classical density wave theory is not a realistic explanation for the spiral structure of M 31. Instead, external causes should be considered, such as interactions with massive gas clouds or dwarf companions of M 31.

  9. Photoevaporating transitional discs and molecular cloud cores

    NASA Astrophysics Data System (ADS)

    Li, Min; Sui, Ning

    2017-04-01

    We investigate the evolution of photoevaporating protoplanetary discs including mass influx from molecular cloud cores. We examine the influence of cloud core properties on the formation and evolution of transitional discs. We use one-dimensional thin disc assumption and calculate the evolution of the protoplanetary disc. The effects of X-ray photoevaporation are also included. Our calculations suggest that most discs should experience the transitional disc phase within 10 Myr. The formation time of a gap and its initial location are functions of the properties of the cloud cores. In some circumstances, discs can open two gaps by photoevaporation alone. The two gaps form when the gas in the disc can expand to large radius and if the mass at large radius is sufficiently small. The surface density profile of the disc determines whether the two gaps can form. Since the structure of a disc is determined by the properties of a molecular cloud core, the core properties determine the formation of two gaps in the disc. We further find that even when the photoevaporation rate is reduced to 10 per cent of the standard value, two gaps can still form in the disc. The only difference is that the formation time is delayed.

  10. Electromagnetic Levitation of a Disc

    ERIC Educational Resources Information Center

    Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.

    2012-01-01

    This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

  11. Galactic archaeology of a thick disc: Excavating ESO 533-4 with VIMOS

    NASA Astrophysics Data System (ADS)

    Comerón, S.; Salo, H.; Janz, J.; Laurikainen, E.; Yoachim, P.

    2015-12-01

    The disc of galaxies is made of the superposition of a thin and a thick disc. Star formation is hosted in the thin discs and contributes to their growth. Thick discs are formed of old stars. The formation mechanisms of thick discs are under discussion. Thick discs might have formed either at high redshift on a short timescale or might have been built slowly over a Hubble-Lemaître time. They may have an internal or an external origin. Here we adopt a galactic archaeology approach to study the thick disc of ESO 533-4, i.e. we study the kinematics and the stellar populations of this galaxy in detail. ESO 533-4 is a Southern, nearby, and almost bulgeless galaxy. We present the first ever Integral Field Unit spectroscopy of an edge-on galaxy with enough depth and quality to study the thick disc. We exposed ESO 533-4 with the blue grism of the VIMOS instrument of the VLT for 6.5 h. The field of view covered an axial extent from ~ 0.1 r25 to ~ 0.7 r25, where r25 is the 25 mag arcsec-2 isophotal radius. This corresponds to the range from ~1 kpc to ~7 kpc. We used pPXF and the MILES library to obtain velocity and stellar population maps. We compared our kinematic data with simple GADGET-2 models. The apparent rotational lag of the thick disc of ESO 533-4 is compatible with that expected from the combinations of two effects: differential asymmetric drift and the projection effects arising from studying a disc a few degrees (2-3°) away from edge-on. Thus, ESO 533-4 contains little or no counter-rotating material. This is compatible with three formation scenarios: the secular dynamical heating of an initially thin disc, the formation of the thick disc at high redshift in an early turbulent disc phase, and the creation of a thick disc in a major merger event. If this last mechanism occurred in all galaxies, it would cause retrograde thick discs in half of them. These retrograde discs have not been observed in the five massive disc galaxies (circular velocity vc ≳ 120 km s-1

  12. Noninvasive radioisotopic technique for detection of platelet deposition in mitral valve prostheses and quantitation of visceral microembolism in dogs

    SciTech Connect

    Dewanjee, M.K.; Fuster, V.; Rao, S.A.; Forshaw, P.L.; Kaye, M.P.

    1983-05-01

    A noninvasive technique has been developed in the dog model for imaging, with a gamma camera, the platelet deposition on Bjoerk-Shiley mitral valve prostheses early postoperatively. At 25 hours after implantation of the prosthesis and 24 hours after intravenous administration of 400 to 500 microCi of platelets labeled with indium-111, the platelet deposition in the sewing ring and perivalvular cardiac tissue can be clearly delineated in a scintiphotograph. An in vitro technique was also developed for quantitation of visceral microemboli in brain, lungs, kidneys, and other tissues. Biodistribution of the labeled platelets was quantitated, and the tissue/blood radioactivity ratio was determined in 22 dogs in four groups: unoperated normal dogs, sham-operated dogs, prosthesis-implanted dogs, and prosthesis-implanted dogs treated with dipyridamole before and aspirin and dipyridamole immediately after operation. Fifteen to 20% of total platelets were consumed as a consequence of the surgical procedure. On quantitation, we found that platelet deposition on the components of the prostheses was significantly reduced in prosthesis-implanted animals treated with dipyridamole and aspirin when compared with prosthesis-implanted, untreated dogs. All prosthesis-implanted animals considered together had a twofold to fourfold increase in tissue/blood radioactivity ratio in comparison with unoperated and sham-operated animals, an indication that the viscera work as filters and trap platelet microemboli that are presumably produced in the region of the mitral valve prostheses. In the dog model, indium-111-labeled platelets thus provide a sensitive marker for noninvasive imaging of platelet deposition on mechanical mitral valve prostheses, in vitro evaluation of platelet microembolism in viscera, in vitro quantitation of surgical consumption of platelets, and evaluation of platelet-inhibitor drugs.

  13. Diagnostic value of mitral annular velocity for constrictive pericarditis in the absence of respiratory variation in mitral inflow velocity.

    PubMed

    Ha, Jong-Won; Oh, Jae K; Ommen, Steve R; Ling, Lieng H; Tajik, A Jamil

    2002-12-01

    Respiratory variation of 25% or more in transmitral early diastolic filling (E) velocity is a well-recognized diagnostic feature of constrictive pericarditis (CP) that is useful for distinguishing it from restrictive cardiomyopathy. However, a subset of patients with CP do not exhibit the typical respiratory change. Recent data showed that mitral annular (E') velocity measured by Doppler tissue echocardiography (DTE) is markedly reduced in patients with restrictive cardiomyopathy whereas E' velocity is well-preserved in CP. This study evaluated the role of DTE for the diagnosis of CP when there is no characteristic respiratory variation of E velocity. From September 1999 to March 2001, 19 patients (17 men, 2 women; mean age, 57 +/- 13 years) with surgically confirmed CP underwent comprehensive echocardiography preoperatively, including pulsed wave and DTE examination with simultaneous recording of respiration. Nine (47%) of the 19 patients had less than 25% respiratory variation in E velocity. There was no significant difference in mitral inflow peak velocity, deceleration time, early-to-late ventricular filling ratio, and E' velocity between patients with and patients without respiratory variation of E velocity of 25% or more. Regardless of the presence or absence of a significant respiratory variation of E velocity, E' velocity was relatively normal (mean, 12 +/- 4 cm/s) in all patients with CP. In conclusion, E' velocity is well preserved in patients with isolated CP even when there is no characteristic respiratory variation of E velocity. Thus, when the respiratory variation in Doppler E velocity is blunted or absent during the evaluation of suspected CP in patients with restrictive mitral inflow velocity, preserved E' velocity shown by DTE should support the diagnosis of CP over a primary myocardial disease.

  14. Kineflex (Centurion) Lumbar Disc Prosthesis: Insertion Technique and 2-Year Clinical Results in 100 Patients

    PubMed Central

    Weinberg, Ian R.; Sliwa, Karen; Sweet, Barry MBE; de Villiers, Malan

    2007-01-01

    Background The Kineflex lumbar disc is a mechanical, unconstrained, re-centering disc prosthesis developed in South Africa. The first implantation took place in October 2002. We present a single-center, prospective, longitudinal study of the first 100 patients treated with the Kineflex lumbar disc. Our objective was to evaluate the insertion technique, clinical outcomes, and patient satisfaction at 2 years postimplantation in 100 consecutive patients with 132 (68 single- and 32 2-level) Kineflex lumbar disc replacements. Methods We determined the exact central placement of all disc implants in the coronal and midsagittal planes. We measured clinical outcome with the Oswestry disability index (ODI), our own questionnaire, and the time needed to return to work. All patients received radiological and clinical follow-up assessments for 2 years after the index procedure. Results Forty-three patients were female. The mean age of the patients at operation was 44.9 years (range, 23–63 years). Postoperative hospitalization averaged 2.8 days (range, 2 to 8 days). All patients who were employed before surgery returned to work 31 ± 16.8 days after the operation. Fifty-six percent of operated disc levels had intervertebral disc heights of less than 5 mm. A 2-year clinical outcome was available for 98 of the 100 patients (58 excellent, 30 good, 7 fair, 3 poor). The ODI score improved from 47.8 ± 16.0 preoperatively to 14.2 ± 14.0 (P < .01) at 2 years. At 2 years, 95% of disc implants were radiologically in the ideal position. The insertion technique, with a released prosthetic mechanism for final placement, allowed ideal placement in the sagittal plane in 98% of discs. The radiographic placement accuracy achieved was equal in patients with preoperative intervertebral disc height below and above 5 mm. Conclusions Good short-term clinical results were achieved with the Kineflex disc in a heterogeneous patient group with a high number of patients with advanced disc

  15. Peripheral Disc Margin Shape and Internal Disc Derangement: Imaging Correlation in Significantly Painful Discs Identified at Provocation Lumbar Discography

    PubMed Central

    Bartynski, W.S.; Rothfus, W.E.

    2012-01-01

    Summary Annular margin shape is used to characterize lumbar disc abnormality on CT/MR imaging studies. Abnormal discs also have internal derangement including annular degeneration and radial defects. The purpose of this study was to evaluate potential correlation between disc-margin shape and annular internal derangement on post-discogram CT in significantly painful discs encountered at provocation lumbar discography (PLD). Significantly painful discs were encountered at 126 levels in 86 patients (47 male, 39 female) studied by PLD where no prior surgery had been performed and response to intradiscal lidocaine after provocation resulted in either substantial/total relief or no improvement after lidocaine administration. Post-discogram CT and discogram imaging was evaluated for disc-margin characteristics (bulge/protrusion), features of disc internal derangement (radial annular defect [RD: radial tear/fissure/annular gap], annular degeneration) and presence/absence of discographic contrast leakage. In discs with focal protrusion, 50 of 63 (79%) demonstrated Grade 3 RD with 13 (21%) demonstrating severe degenerative change only. In discs with generalized-bulge-only, 48 of 63 (76%) demonstrated degenerative change only (primarily Dallas Grade 3) with 15 of 63 (24%) demonstrating a RD (Dallas Grade 3). Differences were highly statistically significant (p<0.001). Pain elimination with intra-discal lidocaine correlated with discographic contrast leakage (p<0.001). Disc-margin shape correlates with features of internal derangement in significantly painful discs encountered at PLD. Discs with focal protrusion typically demonstrate RD while generalized bulging discs typically demonstrated degenerative changes only (p<0.001). Disc-margin shape may provide an important imaging clue to the cause of chronic discogenic low back pain. PMID:22681741

  16. Simulation of the Progression of Intervertebral Disc Degeneration due to Decreased Nutrition Supply

    PubMed Central

    Gu, Weiyong; Zhu, Qiaoqiao; Gao, Xin; Brown, Mark D.

    2014-01-01

    Study Design Simulate the progression of human disc degeneration. Objective The objective of this study was to quantitatively analyze and simulate the changes in cell density, nutrition level, proteoglycan content, water content, and volume change during human disc degeneration using a numerical method. Summary of Background Data Understanding the etiology and progression of intervertebral disc (IVD) degeneration is crucial for developing effective treatment strategies for IVD-degeneration related diseases. During tissue degeneration, the disc undergoes losses of cell viability and activities, changes in extracellular matrix composition and structure, and compromise of the tissue-level integrity and function, which is significantly influenced by the inter-coupled biological, chemical, electrical, and mechanical signals in the disc. Characterizing these signals in human discs in vivo is difficult. Methods A realistic 3D finite element model of the human IVD was developed based on biomechano-electrochemical continuum mixture theory. The theoretical framework and the constitutive relationships were all biophysics based. All the material properties were obtained from experimental results. The cell-mediated disc degeneration process caused by lowered nutrition levels at disc boundaries was simulated and validated by comparing with experimental results. Results Cell density reached equilibrium state in 30 days after reduced nutrition supply at the disc boundary, while the proteoglycan (PG) and water contents reached a new equilibrium state in 55 years. The simulated results for the distributions of PG and water contents within the disc were consistent with the results measured in the literature, except for the distribution of PG content in the sagittal direction. Conclusions Poor nutrition supply has a long-term effect on disc degeneration. PMID:25188596

  17. DISC1 knockdown impairs the tangential migration of cortical interneurons by affecting the actin cytoskeleton

    PubMed Central

    Steinecke, André; Gampe, Christin; Nitzsche, Falk; Bolz, Jürgen

    2014-01-01

    Disrupted-in-Schizophrenia 1 (DISC1) is a risk gene for a spectrum of major mental disorders. It has been shown to regulate radial migration as well as dendritic arborization during neurodevelopment and corticogenesis. In a previous study we demonstrated through in vitro experiments that DISC1 also controls the tangential migration of cortical interneurons originating from the medial ganglionic eminence (MGE). Here we first show that DISC1 is necessary for the proper tangential migration of cortical interneurons in the intact brain. Expression of EGFP under the Lhx6 promotor allowed us to analyze exclusively interneurons transfected in the MGE after in utero electroporation. After 3 days in utero, DISC1 deficient interneurons displayed prolonged leading processes and, compared to control, fewer neurons reached the cortex. Time-lapse video microscopy of cortical feeder-layers revealed a decreased migration velocity due to a reduction of soma translocations. Immunostainings indicated that DISC1 is co-localized with F-actin in the growth cone-like structure of the leading process. DISC1 knockdown reduced F-actin levels whereas the overall actin level was not altered. Moreover, DISC1 knockdown also decreased levels of phosphorylated Girdin, which cross-links F-actin, as well as the Girdin-activator pAkt. In contrast, using time-lapse video microscopy of fluorescence-tagged tubulin and EB3 in fibroblasts, we found no effects on microtubule polymerization when DISC1 was reduced. However, DISC1 affected the acetylation of microtubules in the leading processes of MGE-derived cortical interneurons. Together, our results provide a mechanism how DISC1 might contribute to interneuron migration thereby explaining the reduced number of specific classes of cortical interneurons in some DISC1 mouse models. PMID:25071449

  18. A Structurally and Functionally Biomimetic Biphasic Scaffold for Intervertebral Disc Tissue Engineering

    PubMed Central

    Choy, Andrew Tsz Hang; Chan, Barbara Pui

    2015-01-01

    Tissue engineering offers high hopes for the treatment of intervertebral disc (IVD) degeneration. Whereas scaffolds of the disc nucleus and annulus have been extensively studied, a truly biomimetic and mechanically functional biphasic scaffold using naturally occurring extracellular matrix is yet to be developed. Here, a biphasic scaffold was fabricated with collagen and glycosaminoglycans (GAGs), two of the most abundant extracellular matrix components in the IVD. Following fabrication, the scaffold was characterized and benchmarked against native disc. The biphasic scaffold was composed of a collagen-GAG co-precipitate making up the nucleus pulposus-like core, and this was encapsulated in multiple lamellae of photochemically crosslinked collagen membranes comprising the annulus fibrosus-like lamellae. On mechanical testing, the height of our engineered disc recovered by ~82-89% in an annulus-independent manner, when compared with the 99% recovery exhibited by native disc. The annulus-independent nature of disc height recovery suggests that the fluid replacement function of the engineered nucleus pulposus core might mimic this hitherto unique feature of native disc. Biphasic scaffolds comprised of 10 annulus fibrosus-like lamellae had the best overall mechanical performance among the various designs owing to their similarity to native disc in most aspects, including elastic compliance during creep and recovery, and viscous compliance during recovery. However, the dynamic mechanical performance (including dynamic stiffness and damping factor) of all the biphasic scaffolds was similar to that of the native discs. This study contributes to the rationalized design and development of a biomimetic and mechanically viable biphasic scaffold for IVD tissue engineering. PMID:26115332

  19. [Optic disc granuloma secondary to sarcoidosis].

    PubMed

    Qu-Knafo, L; Auregan-Giocanti, A

    2017-02-01

    We report a case of optic disc granuloma due to sarcoidosis. A 64-year-old, caucasian female with a history of pulmonary sarcoidosis presented with a vision loss on her left eye. The ophthalmologic examination revealed a discrete optic disc infiltrate compatible with the diagnosis of optic disc granuloma. Fluorescein angiography showed diffusion and impregnation of the granuloma without vascularitis. The optical coherence tomography demonstrated a homogenous and isoreflective lesion at the optic disc. The patient recovered her visual acuity after systemic corticosteroid treatment. Isolated optic disc granuloma is a rare condition of ocular sarcoidosis.

  20. Kingella kingae endocarditis: A rare case of mitral valve perforation

    PubMed Central

    Holmes, Anthony A; Hung, Tawny; Human, Derek G; Campbell, Andrew I M

    2011-01-01

    Kingella kingae, a HACEK (Haemophilus parainfluenzae, Aggregatibacter actinomycetemcomitans, Aggregatibacter aphrophilus, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae) organism, is a common resident of the upper airway in children; it has been associated with endocarditis in children with pre-existing heart conditions. This case report describes K. kingae endocarditis leading to valvular damage in a previously healthy 18-month-old child. Our patient developed a K. kingae bacteremia that was later complicated by meningitis, septic embolic stroke, and endocarditis of the mitral valve, leading to perforation of the posterolateral leaflet. The patient was initially treated conservatively with cefotaxime but, subsequently, required a mitral valve repair with a pericardial patch and annuloplasty. This report draws attention to the need for clinicians to be aware of the potentially serious complications of K. kingae infection in young children. If K. kingae infection is suspected then therapy should be initiated promptly with a β-lactam, followed by early echocardiographic assessment. This case also highlights the lack of specific guidelines available for K. kingae endocarditis. PMID:21976892

  1. Kingella kingae endocarditis: A rare case of mitral valve perforation.

    PubMed

    Holmes, Anthony A; Hung, Tawny; Human, Derek G; Campbell, Andrew I M

    2011-07-01

    Kingella kingae, a HACEK (Haemophilus parainfluenzae, Aggregatibacter actinomycetemcomitans, Aggregatibacter aphrophilus, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae) organism, is a common resident of the upper airway in children; it has been associated with endocarditis in children with pre-existing heart conditions. This case report describes K. kingae endocarditis leading to valvular damage in a previously healthy 18-month-old child. Our patient developed a K. kingae bacteremia that was later complicated by meningitis, septic embolic stroke, and endocarditis of the mitral valve, leading to perforation of the posterolateral leaflet. The patient was initially treated conservatively with cefotaxime but, subsequently, required a mitral valve repair with a pericardial patch and annuloplasty. This report draws attention to the need for clinicians to be aware of the potentially serious complications of K. kingae infection in young children. If K. kingae infection is suspected then therapy should be initiated promptly with a β-lactam, followed by early echocardiographic assessment. This case also highlights the lack of specific guidelines available for K. kingae endocarditis.

  2. [Association of anorexia nervosa and mitral valve prolapse].

    PubMed

    Amano, K; Sakamoto, T; Hada, Y; Hasegawa, I; Takahashi, T; Suzuki, J; Takahashi, H

    1986-01-01

    Four cases of anorexia nervosa recently encountered were reported in respect to their cardiovascular manifestations including prolapse of the cardiac valves and other poorly recognized cardiac findings. All four patients, aged 13 to 32 years, were women and had marked emaciation (35 to 44% weight loss of the ideal body weight) with typical hormone abnormalities. Chest radiographs showed a small cardiac shadow, and sinus bradycardia with low voltage was present in their electrocardiograms. One case, 13-year-old, had a mid-systolic click and occasionally a late systolic murmur, and also an abdominal continuous hum. Echocardiography including two-dimensional color flow-mapping disclosed mitral valve prolapse in all, and tricuspid valve prolapse in two. Mild to moderate pericardial effusion was noted in all between the right ventricle and diaphragm, and pericardiocentesis in one case had no effect on the valve movements. No inflammatory changes were observed in the specimen of the pericardium and also of the fluid. An association of mitral valve prolapse and anerexia nervosa was discussed based on the previous studies, but the final conclusion remains unknown.

  3. Percutaneous approaches to valve repair for mitral regurgitation.

    PubMed

    Feldman, Ted; Young, Amelia

    2014-05-27

    Percutaneous therapy has emerged as an option for treatment of mitral regurgitation for selected, predominantly high-risk patients. Most of the percutaneous approaches are modifications of existing surgical approaches. Catheter-based devices mimic these surgical approaches with less procedural risk, due to their less-invasive nature. Percutaneous annuloplasty can be achieved indirectly via the coronary sinus or directly from retrograde left ventricular access. Catheter-based leaflet repair with the MitraClip (Abbott Laboratories, Abbott Park, Illinois) is accomplished with an implantable clip to mimic the surgical edge-to-edge leaflet repair technique. A large experience with MitraClip has been reported, and several other percutaneous approaches have been successfully used in smaller numbers of patients to demonstrate proof of concept, whereas others have failed and are no longer under development. There is increasing experience in both trials and practice to begin to define the clinical utility of percutaneous leaflet repair, and annuloplasty approaches are undergoing significant development. Transcatheter mitral valve replacement is still in early development.

  4. Adult women with mitral valve prolapse are more flexible

    PubMed Central

    Araujo, C; Chaves, C

    2005-01-01

    Background: Mitral valve prolapse (MVP) is common in women. Other clinical features such as flexibility and hyperlaxity are often associated with MVP, as there is a common biochemical and histological basis for collagen tissue characteristics, range of joint motion, and mitral leaflet excursion. Objective: To confirm whether adult women with MVP are more flexible and hypermobile than those without. Methods: Data from 125 women (mean age 50 years), 31 of them with MVP, were retrospectively analysed with regard to clinical and kinanthropometric aspects. Passive joint motion was evaluated in 20 body movements using Flexitest and three laxity tests. Flexitest individual movements (0 to 4) and overall Flexindex scores were obtained in all subjects by the same investigator. Results: Women with MVP were lighter, less endomorphic and mesomorphic, and more linear. The Flexindex was significantly higher in the women with MVP, both absolute (48 (1.6) v 41 (1.3); p<0.01) and centile for age (67 v 42; p<0.01) values. In 13 out of 20 movements, the Flexitest scores were significantly higher for the women with MVP. Signs of hyperlaxity were about five times more common in these women: 74% v 16% (p<0.01). Scores of 0 and 1 in elbow extension, absence of hyperlaxity, and a Flexindex centile below 65 were almost never found in women with MVP. Conclusion: Flexitest, alone or combined with hyperlaxity tests, may be useful in the assessment of adult women with MVP. PMID:16183767

  5. Simultaneous transapical transcatheter aortic valve replacement and transcatheter mitral valve replacement for native valvular stenosis.

    PubMed

    Elkharbotly, Ali; Delago, Augustin; El-Hajjar, Mohammad

    2016-06-01

    Transcatheter aortic valve replacement (TAVR) is well established for patients who cannot undergo surgery (Leon et al., N Engl J Med 2010;363:1597) or are high risk for surgery (Smith et al., N Engl J Med 2011;364:2187-2198). Experience with the TAVR procedure has led to recent reports of successful transcatheter mitral valve replacement (TMVR) procedures (Cheung et al., J Am Coll Cardiol 2014;64:1814; Seiffert et al., J Am Coll Cardiol Interv 2012;5:341-349) separately or simultaneously with the TAVR. However, these reports were of simultaneous valve-in-valve procedures (Cheung Anson, et al. J Am Coll Cardiol 2013;61:1759-1766). A recent report from Portugal also reported simultaneous transpical implantation of an inverted transcatheter aortic valve-in-ring in the mitral position and transcatheter aortic valve (Hasan et al., Circulation 2013;128:e74-e76). There has been an experience of TMVR only in native mitral valve for mitral valve stenosis, but none in both aortic and mitral valves. We report the first in human case of simultaneous transapical TAVR and TMVR in native valves secondary to valvular stenosis. Our patient was not a candidate for percutaneous balloon mitral valvuloplasty secondary to a high Wilkins Score. Sizing of the aortic valve was based on the transesophageal echocardiogram (TEE), whereas sizing of the mitral valve was based on TEE measurements and balloon inflation during left ventriculography. © 2015 Wiley Periodicals, Inc.

  6. A Dynamic Heart System to Facilitate the Development of Mitral Valve Repair Techniques

    PubMed Central

    Richards, Andrew L.; Cook, Richard C.; Bolotin, Gil; Buckner, Gregory D.

    2013-01-01

    Objective The development of a novel surgical tool or technique for mitral valve repair can be hampered by cost, complexity, and time associated with performing animal trials. A dynamically pressurized model was developed to control pressure and flowrate profiles in intact porcine hearts in order to quantify mitral regurgitation and evaluate the quality of mitral valve repair. Methods A pulse duplication system was designed to replicate physiological conditions in explanted hearts. To test the capabilities of this system in measuring varying degrees of mitral regurgitation, the output of eight porcine hearts was measured for two different pressure waveforms before and after induced mitral valve failure. Four hearts were further repaired and tested. Measurements were compared with echocardiographic images. Results For all trials, cardiac output decreased as left ventricular pressure was increased. After induction of mitral valve insufficiencies, cardiac output decreased, with a peak regurgitant fraction of 71.8%. Echocardiography clearly showed increases in regurgitant severity from post-valve failure and with increased pressure. Conclusions The dynamic heart model consistently and reliably quantifies mitral regurgitation across a range of severities. Advantages include low experimental cost and time associated with each trial, while still allowing for surgical evaluations in an intact heart. PMID:19224369

  7. Impact of planet-planet scattering on the formation and survival of debris discs

    NASA Astrophysics Data System (ADS)

    Marzari, F.

    2014-10-01

    Planet-planet scattering is a major dynamical mechanism able to significantly alter the architecture of a planetary system. In addition to that, it may also affect the formation and retention of a debris disc by the system. A violent chaotic evolution of the planets can easily clear leftover planetesimal belts preventing the ignition of a substantial collisional cascade that can give origin to a debris disc. On the other end, a mild evolution with limited steps in eccentricity and semimajor axis can trigger the formation of a debris disc by stirring an initially quiet planetesimal belt. The variety of possible effects that planet-planet scattering can have on the formation of debris discs is analysed and the statistical probability of the different outcomes is evaluated. This leads to the prediction that systems which underwent an episode of chaotic evolution might have a lower probability of harbouring a debris disc.

  8. In Vitro System for Measuring Chordal Force Changes Following Mitral Valve Patch Repair

    PubMed Central

    Ostli, B; Vester-Petersen, J; Askov, JB; Honge, JL; Levine, RA; Hagège, A; Nielsen, SL; Hasenkam, JM; Nygaard, H; Jensen, MO

    2013-01-01

    Background Attention towards optimization of mitral valve repair methods is increasing. Patch augmentation is one strategy utilized to correct functional mitral regurgitation or systolic anterior motion in complex mitral valve repairs. This article describes a system for investigating the redistribution of chordae tendineae tension as a reflection of altered stress distribution of the valve leaflet following patch augmentation. Methods and materials An in vitro test setup was constructed to hold native porcine mitral valves containing an annulus and papillary muscle positioning system. The alterations caused by patch augmentation should be visual from both the atrial and ventricular views. Ventricular pressure was regulated stepwise in a range of 0-150 mmHg. To test the system, the anterior mitral leaflet was extended by a pericardial patch sutured to the mid/basal part of the leaflet, and the chordae tendineae force was measured as the ventricular pressure was applied. Results The system demonstrated the capacity to hold native porcine mitral valves and introducing patch repairs according to clinical practice. The porcine mitral valve test setup indicated strong correlation between the forces in the mitral valve secondary chordae tendineae and the applied transvalvular pressure (R2 = 0.95). Conclusion This test setup proved the ability to obtain normal mid-systolic mitral valve function, secondary chordae force measurements, and important preservation of the visual access: Hence, obtaining the pressure-force relationship as well as identifying any shift of the secondary chordae insertion point on the anterior leaflet relative to the coaptation zone was made possible. PMID:26273417

  9. Ventricular Reconstruction Results in Improved Left Ventricular Function and Amelioration of Mitral Insufficiency

    PubMed Central

    Kaza, Aditya K.; Patel, Mayank R.; Fiser, Steven M.; Long, Stewart M.; Kern, John A.; Tribble, Curtis G.; Kron, Irving L.

    2002-01-01

    Introduction Surgical restoration of the left ventricular wall (Dor procedure) has been advocated as a therapy for left ventricular dysfunction due to ischemic cardiomyopathy. This procedure involves placement of an endoventricular patch through a ventriculotomy. Methods We reviewed our series of patients that underwent the Dor procedure within the past 4 years and examined their pre and postoperative ventricular function and mitral valve function. Pre and postoperative ejection fraction and degree of mitral regurgitation were analyzed using the paired Student t-test. We hypothesized that this procedure would result in improved ventricular function and that it would also help improve mitral valve function. Results Thirty-four patients underwent this procedure, with one death. Of these, 30 patients underwent concomitant coronary artery bypass grafting and 8 patients had mitral intervention (seven had an Alfieri repair of the mitral valve, and one had mitral valve annuloplasty). The average preoperative ejection fraction among these patients was 26.8% (range 10–45%). The postoperative ejection fraction was significantly higher at 35.4% (range 25–52%) (P < .001). We noted an improvement in ejection fraction in 27 patients (82%). We also noted that 21 of 33 patients (64%) had improvement in the degree of mitral regurgitation based on echocardiography data (P < .001). Conclusions We conclude that the Dor procedure results in improvement in the left ventricular function. Furthermore, we also note that this procedure ameliorates mitral regurgitation in a majority of these patients even in the absence of associated mitral valve procedures, probably due to reduction in the size of the ventricle and improved orientation of the papillary muscles. PMID:12035039

  10. Depressed contractile function due to canine mitral regurgitation improves after correction of the volume overload.

    PubMed Central

    Nakano, K; Swindle, M M; Spinale, F; Ishihara, K; Kanazawa, S; Smith, A; Biederman, R W; Clamp, L; Hamada, Y; Zile, M R

    1991-01-01

    It is known that long-standing volume overload on the left ventricle due to mitral regurgitation eventually leads to contractile dysfunction. However, it is unknown whether or not correction of the volume overload can lead to recovery of contractility. In this study we tested the hypothesis that depressed contractile function due to volume overload in mitral regurgitation could return toward normal after mitral valve replacement. Using a canine model of mitral regurgitation which is known to produce contractile dysfunction, we examined contractile function longitudinally in seven dogs at baseline, after 3 mo of mitral regurgitation, 1 mo after mitral valve replacement, and 3 mo after mitral valve replacement. After 3 mo of mitral regurgitation (regurgitant fraction 0.62 +/- 0.04), end-diastolic volume had nearly doubled from 68 +/- 6.8 to 123 +/- 12.1 ml (P less than 0.05). All five indices of contractile function which we examined were depressed. For instance, maximum fiber elastance (EmaxF) obtained by assessment of time-varying elastance decreased from 5.95 +/- 0.71 to 2.25 +/- 0.18 (P less than 0.05). The end-systolic stiffness constant (k) was also depressed from 4.2 +/- 0.4 to 2.1 +/- 0.3. 3 mo after mitral valve replacement all indexes of contractile function had returned to or toward normal (e.g., EmaxF 3.65 +/- 0.21 and k 4.2 +/- 0.3). We conclude that previously depressed contractile function due to volume overload can improve after correction of the overload. PMID:1828252

  11. Pulmonary venous flows reflect changes in left atrial hemodynamics during mitral balloon valvotomy

    NASA Technical Reports Server (NTRS)

    Yalcin, Fatih; El-Amrousy, Mahmoud; Muderrisoglu, Haldun; Korkmaz, Mehmet; Flachskampf, Frank; Tuzcu, Murat; Garcia, Mario G.; Thomas, James D.

    2002-01-01

    Patients with mitral stenosis have usually blunted pulmonary venous (PV) flow, because of decreased mitral valve area and diastolic dysfunction. The authors compared changes in Doppler PV velocities by using transesophageal echocardiography (TEE) against hemodynamics parameters before and after mitral balloon valvotomy to observe relevance of PV velocities and endsystolic left atrial (LA) pressure-volume relationship. In 25 patients (aged 35 +/- 17 years) with mitral stenosis in sinus rhythm, changes in LA pressure and volumes were compared with PV velocities before and after valvotomy. Mitral valve area, mitral gradients, and deceleration time were obtained. Mitral valve area and mitral gradients changed from 1 +/- 0.2 cm2 and 14.6 +/- 5.4 mmHg to 1.9 +/- 0.3 cm2 and 6.3 +/- 1.7 mmHg, respectively (p<0.001). AR peak reverse flow velocity and AR duration decreased from 29 +/- 13 cm/s and 110 =/- 30 msec to 19 +/- 6 cm/s and 80 +/- 29 msec respectively (p<0.001). Transmitral Doppler E wave deceleration time decreased from 327 +/- 85 to 209 +/- 61 s and cardiac output increased from 4.2 +/- 1.0 to 5.2 +/- 1.1 L/minute (p<0.001). The changes in LA pressure were correlated with changes in S/D (r=0.57, p<0.05). The changes in endsystolic LA pressure-volume relationship were also correlated with changes in S/D (r=0.52, p<0.05). Endsystolic LA pressure-volume relationship decreased after mitral balloon valvotomy, as a result of a large decrease in pressure. PV systolic/diastolic (S/D) waves ratio reflects endsystolic LA pressure-volume relationship and may be used as another indicator of successful valvotomy.

  12. Rock deformation equations and application to the study on slantingly installed disc cutter

    NASA Astrophysics Data System (ADS)

    Zhang, Zhao-Huang; Meng, Liang; Sun, Fei

    2014-08-01

    At present the mechanical model of the interaction between a disc cutter and rock mainly concerns indentation experiment, linear cutting experiment and tunnel boring machine (TBM) on-site data. This is not in line with the actual rock-breaking movement of the disc cutter and impedes to some extent the research on the rock-breaking mechanism, wear mechanism and design theory. Therefore, our study focuses on the interaction between the slantingly installed disc cutter and rock, developing a model in accordance with the actual rock-breaking movement. Displacement equations are established through an analysis of the velocity vector at the rock-breaking point of the disc cutter blade; the functional relationship between the displacement parameters at the rock-breaking point and its rectangular coordinates is established through an analysis of micro-displacement vectors at the rock-breaking point, thus leading to the geometric equations of rock deformation caused by the slantingly installed disc cutter. Considering the basically linear relationship between the cutting force of disc cutters and the rock deformation before and after the leap break of rock, we express the constitutive relations of rock deformation as generalized Hooke's law and analyze the effect of the slanting installation angle of disc cutters on the rock-breaking force. This will, as we hope, make groundbreaking contributions to the development of the design theory and installation practice of TBM.

  13. [Large mitral annulus myxoma presenting with syncope: Report of one case].

    PubMed

    Vega, Julián; Gabrielli, Luigi; Olivares, Gabriel; Córdova, Samuel; Méndez, Manuel; González, Rodrigo

    2016-12-01

    We report a 23-year-old woman, with three recent exertional syncopes. Transthoracic (TTE) and transesophageal (TEE) echocardiography found a large heterogeneous mass (38 x 35 mm) arising from the posterior mitral annulus, protruding in systole through the left ventricular outflow tract (LVOT). Heart MRI confirmed the echocardiography findings, suggesting a cardiac myxoma. Cardiac surgery accomplished the complete resection of the lesion, confirming a mass arising from the posterior mitral annulus and preserving mitral anatomy and function. Pathology was positive for a myxoma. Uneventful evolution allowed the discharge of the patient at the fifth postoperative day. Control TTE discarded any complication.

  14. Late embolization of prosthetic mitral valve occluder with survival following reoperation.

    PubMed

    Hughes, D A; Leatherman, L L; Norman, J C; Cooley, D A

    1975-02-01

    Embolization of the occluder from a prosthetic mitral valve is an extremely rare event. Previous reports in the literature have described the uniformly fatal outcome of this complication. A case in which the occluder from a Wada-Cutter mitral prosthesis embolized five years following implantation is presented. The patient survived following emergency reoperation. Several unique features of escaped mitral poppet are discussed. Depending upon cardiac reserves, patients who have this complication may live long enough to allow emergency operative intervention and eventual recovery.

  15. Initial experience of mitral valve replacement with total preservation of both valve leaflets.

    PubMed Central

    Dottori, V; Barberis, L; Lijoi, A; Giambuzzi, M; Maccario, M; Faveto, C

    1994-01-01

    We compared a series of 7 consecutive patients who underwent mitral valve replacement with preservation of both leaflets to a control group of 97 patients who underwent standard mitral valve replacement at our institution during the same period. Use of inotropic drugs and duration of postoperative intensive care were compared and shown to be markedly reduced in the study group; however, statistical analysis was not applied due to the small number of patients. Comparison of the available pre- and postoperative echocardiographic values showed a decrease in left ventricular end-diastolic and end-systolic diameters in patients with preserved leaflets, particularly in those with mitral regurgitation of degenerative origin. PMID:8000269

  16. Acute Multiple Cerebral Infarction in a Patient with an Accessory Mitral Valve

    PubMed Central

    Misumi, Ikuo; Nagao, Asako; Iwamoto, Katsuya; Honda, Tsuyoshi; Ishii, Masanobu; Ueyama, Hidetsugu; Maeda, Yasushi; Ishizaki, Masatoshi; Kurisaki, Ryoichi; Okazaki, Toshio; Yamashita, Tetsuji; Fujimoto, Akiko; Honda, Yumi

    2017-01-01

    A 96-year-old woman developed hemiparesis 2 weeks after orthopedic surgery. Magnetic resonance imaging revealed multiple cerebral infarctions in the bilateral hemisphere. Transthoracic echocardiography revealed a mobile structure attached to the anterior mitral leaflet that protruded toward the left ventricular outflow tract. The structure was identified as an accessory mitral valve. Doppler echocardiography showed that there was no significant left ventricular outflow obstruction. This is a rare case of a silent accessory mitral valve that was detected after multiple cerebral infarctions. PMID:28090044

  17. Double-Orifice Mitral Valve in an Eight-Year-Old Boy.

    PubMed

    Segreto, Antonio; De Salvatore, Sergio; Chiusaroli, Alessandro; Bizzarri, Federico; Van Wyk, Cornelius; Congiu, Stefano

    2015-07-01

    The case is described of an eight-year-old boy who required an operation for moderate mitral regurgitation due to a double-orifice mitral valve (DOMV). The DOMV, which was clearly demonstrated by transthoracic echocardiography, had a central fibrous bridge. Mitral valve repair using a 5/0 Prolene suture placed at the level of the superior commissure of each hole to stabilize the valve, and ring annuloplasty with Edwards Physio ring, was successfully performed. Intraoperative real-time transesophageal echocardiography showed the repaired DOMV to be without regurgitation or stenosis.

  18. Predictors of Exercise-Induced Pulmonary Hypertension in Patients with Asymptomatic Degenerative Mitral Regurgitation: Mechanistic Insights from 2D Speckle-Tracking Echocardiography

    PubMed Central

    Kamijima, Ryo; Suzuki, Kengo; Izumo, Masaki; Kuwata, Shingo; Mizukoshi, Kei; Takai, Manabu; Kou, Seisyou; Hayashi, Akio; Kida, Keisuke; Harada, Tomoo; Akashi, Yoshihiro J.

    2017-01-01

    Presence of exercise-induced pulmonary hypertension (EIPH) in asymptomatic degenerative mitral regurgitation (DMR) determines prognosis. This study aimed to elucidate the mechanism and predictors of EIPH in asymptomatic DMR. Ninety-one consecutive asymptomatic patients with DMR who underwent exercise stress echocardiography were prospectively included. We obtained various conventional echocardiographic parameters at rest and during peak exercise, as well as left atrial (LA) function at rest using 2-dimensional speckle-tracking analysis. The 25 patients (33.3%) with EIPH were significantly older and had a greater ratio of mitral peak velocity of early filling to early diastolic mitral annular velocity during peak exercise than those without EIPH. LA strain (LAS)-s and LAS-e, indices of LA reservoir and conduit function, respectively, were significantly lower in those with EIPH than in those without EIPH. Multivariate analysis indicated that LAS-s was the only resting echocardiographic parameter that independently predicted EIPH, with a cut-off value of 26.9%. Furthermore, Kaplan-Meier curve analysis showed that symptom-free survival was markedly lower among those with reduced LAS-s. In conclusion, decreased LA reservoir function contributes to EIPH, and LAS-s at rest is a useful indicator for predicting EIPH in asymptomatic patients with DMR. PMID:28071674

  19. Percutaneous Transcatheter Mitral Valve Replacement: Patient-specific Three-dimensional Computer-based Heart Model and Prototyping.

    PubMed

    Vaquerizo, Beatriz; Theriault-Lauzier, Pascal; Piazza, Nicolo

    2015-12-01

    Mitral regurgitation is the most prevalent valvular heart disease worldwide. Despite the widespread availability of curative surgical intervention, a considerable proportion of patients with severe mitral regurgitation are not referred for treatment, largely due to the presence of left ventricular dysfunction, advanced age, and comorbid illnesses. Transcatheter mitral valve replacement is a promising therapeutic alternative to traditional surgical valve replacement. The complex anatomical and pathophysiological nature of the mitral valvular complex, however, presents significant challenges to the successful design and implementation of novel transcatheter mitral replacement devices. Patient-specific 3-dimensional computer-based models enable accurate assessment of the mitral valve anatomy and preprocedural simulations for transcatheter therapies. Such information may help refine the design features of novel transcatheter mitral devices and enhance procedural planning. Herein, we describe a novel medical image-based processing tool that facilitates accurate, noninvasive assessment of the mitral valvular complex, by creating precise three-dimensional heart models. The 3-dimensional computer reconstructions are then converted to a physical model using 3-dimensional printing technology, thereby enabling patient-specific assessment of the interaction between device and patient. It may provide new opportunities for a better understanding of the mitral anatomy-pathophysiology-device interaction, which is of critical importance for the advancement of transcatheter mitral valve replacement.

  20. Herschel SPIRE observations of the TWA brown dwarf disc 2MASSW J1207334-393254

    NASA Astrophysics Data System (ADS)

    Riaz, B.; Lodato, G.; Stamatellos, D.; Gizis, J. E.

    2012-05-01

    We present Herschel/SPIRE observations for the 2MASS 1207334-393254 (2M1207) system. Based on radiative transfer modelling of near-infrared to submillimetre data, we estimate a disc mass of 3 ± 2 MJup and an outer disc radius of 50-100 au for the 2M1207A disc. The relative disc mass for 2M1207A is similar to the T Tauri star TW Hya, which indicates that massive discs are not underabundant around substellar objects. In probing the various formation mechanisms for this system, we find that core accretion is highly uncertain mainly due to the large separation between the primary and the companion. Disc fragmentation could be a likely scenario based on analytical models, and if the disc initially was more massive than its current estimate. Considering that the TW Hydrae Association (TWA) is sparsely populated, this system could have formed via one of the known binary formation mechanisms (e.g. turbulent fragmentation of a core) and survived disruption at an early stage.

  1. Immediate Outcome of Balloon Mitral Valvuloplasty with JOMIVA Balloon during Pregnancy

    PubMed Central

    Ramasamy, Ramona; Kaliappan, Tamilarasu; Gopalan, Rajendiran; Palanimuthu, Ramasmy; Anandhan, Premkrishna

    2017-01-01

    Introduction Rheumatic mitral stenosis is the most common Valvular Heart Disease encountered during pregnancy. Balloon Mitral Valvuloplasty (BMV) is one of the treatment option available if the symptoms are refractory to the medical management and the valve anatomy is suitable for balloon dilatation. BMV with Inoue balloon is the most common technique being followed worldwide. Over the wire BMV is a modified technique using Joseph Mitral Valvuloplasty (JOMIVA) balloon catheter which is being followed in certain centres. Aim To assess the immediate post procedure outcome of over the wire BMV with JOMIVA balloon. Materials and Methods Clinical and echocardiographic parameters of pregnant women with significant mitral stenosis who underwent elective BMV with JOMIVA balloon in our institute from 2005 to 2015 were analysed retrospectively. Severity of breathlessness (New York Heart Association Functional Class), and duration of pregnancy was included in the analysis. Pre procedural echocardiographic parameters which included severity of mitral stenosis and Wilkin’s scoring were analysed. Clinical, haemodynamic and echocardiographic outcomes immediately after the procedure were analysed. Results Among the patients who underwent BMV in our Institute 38 were pregnant women. Twenty four patients (63%) were in New York Heart Association (NYHA) Class III. All of them were in sinus rhythm except two (5%) who had atrial fibrillation. Thirty four patients (89.5%) were in second trimester of pregnancy at the time of presentation and four (10.5%) were in third trimester. Echocardiographic analysis of the mitral valve showed that the mean Wilkin’s score was 7.3. Mean mitral valve area pre procedure was 0.8 cm2. Mean gradient across the valve was 18 mmHg. Ten patients (26.5%) had mild mitral regurgitation and none had more than mild mitral regurgitation. Thirty six patients had pulmonary hypertension as assessed by tricuspid regurgitation jet velocity. All of them underwent BMV

  2. Dumb-bell in the heart: rare case of biatrial myxoma with mitral regurgitation.

    PubMed

    Ananthanarayanan, Chandrasekaran; Bishnoi, Arvind Kumar; Ramani, Jayadip; Gandhi, Hemang

    2016-10-01

    Cardiac myxomas are rare intracardiac tumors, and the majority are benign myxomas involving the left atrium. We report a case of the very rare occurrence of biatrial myxoma associated with mitral regurgitation, which was successfully treated.

  3. Transesophageal Echocardiographic Diagnosis and Management of Circumflex Artery Injury Following Mitral Valve Repair

    PubMed Central

    Murugesan, Chinnamuthu; Raghu, Bheemaiah; Rao, Parachuri Venkateshwara

    2011-01-01

    A 16-year-old woman with severe mitral regurgitation as a result of rheumatic heart disease underwent mitral valve repair with posterior mitral annuloplasty. ST elevation was observed in leads II, III and aVF after weaning from cardiopulmonary bypass. On transesophageal echocardiography, the stenosis of the circumflex artery was suggested by a modified midesophageal long axis. Since the patient was hemodynamically unstable, an emergency coronary angiography could not be considered. An urgent cardiopulmonary bypass was re-instituted; the first two sutures in the P1 region of the posterior mitral annulus were translocated more superficially. Transesophageal echocardiography revealed good opening of the circumflex artery and improvement in regional wall motion abnormality following the corrected procedure.

  4. Functional tricuspid regurgitation in mitral valve disease: epidemiology and prognostic implications.

    PubMed

    Anyanwu, Ani C; Adams, David H

    2010-01-01

    In this review we summarize the data on epidemiology and natural history of functional tricuspid valve regurgitation as it applies to surgery for mitral valve disease. Tricuspid regurgitation in the context of mitral valve disease is frequent and is associated with substantial reduction in survival and quality of life. In many patients, the correction of left-sided cardiac lesions does not lead to resolution of tricuspid regurgitation. Significant tricuspid regurgitation after mitral valve surgery portends a poor prognosis, a course that is often not altered by subsequent surgical therapy. Although a liberal approach to tricuspid annuloplasty is widely practiced, the evidence that this approach alters the natural history of functional tricuspid regurgitation is not yet available, so it is not certain how much of the negative impact of tricuspid regurgitation is causative, rather than confounding, and to what degree we will improve long-term outcomes of mitral valve surgery by liberal tricuspid annuloplasty.

  5. Designing innovative retractors and devices to facilitate mitral valve repair surgery

    PubMed Central

    Yozu, Ryohei

    2015-01-01

    Various devices have been developed to facilitate mitral valve surgery, including those that improve mitral valve exposure and assist surgeons with associated procedures. Choosing appropriate supporting devices when performing minimally invasive mitral valve surgery (MIMVS) through a minithoracotomy with endoscopic assistance is critical. Depending on the surgeon’s preference, trans-thoracic or trans-working-port left atrial retractors can be utilized. Although the trans-thoracic retractors provide a simple and orderly working space around the minithoracotomy working port, the positioning of the shaft is difficult and there is an implicit risk of chest wall bleeding. On the other hand, the trans-working-port type provides excellent exposure, is easily handled and manipulated, and facilitates surgeries involving various anatomical structures without special training. A great deal of understanding and knowledge about retractors is necessary to achieve the optimal exposure required to facilitate surgical techniques, and to maintain a reproducible and safe surgical system during mitral valve surgery. PMID:26309847

  6. Isolated parachute mitral valve in a 29 years old female; a case report

    PubMed Central

    Toufan, Mehrnoush; Mahmoudi, Seyed Sajjad

    2016-01-01

    A 29-year old female patient was referred to our hospital for evaluation of dyspnea NYHA class I which begun from several months ago. The only abnormal sign found on physical examination was a grade 2/6 systolic murmur at the apex position without radiation. Echocardiography revealed normal left and right ventricular sizes and systolic function, and only one papillary muscle in left ventricular (LV) cavity which all chordae tendineae inserted into that muscle. The mitral valve orifice was eccentrically located at the lateral side with mild to moderate mitral regurgitation but without significant mitral stenosis. No other congenital heart anomalies were identified. Thus, the final diagnosis was isolated parachute mitral valve (IPMV). She was one of the very rare IPMV cases have ever been reported in adults PMID:27069567

  7. Designing innovative retractors and devices to facilitate mitral valve repair surgery.

    PubMed

    Okamoto, Kazuma; Yozu, Ryohei

    2015-07-01

    Various devices have been developed to facilitate mitral valve surgery, including those that improve mitral valve exposure and assist surgeons with associated procedures. Choosing appropriate supporting devices when performing minimally invasive mitral valve surgery (MIMVS) through a minithoracotomy with endoscopic assistance is critical. Depending on the surgeon's preference, trans-thoracic or trans-working-port left atrial retractors can be utilized. Although the trans-thoracic retractors provide a simple and orderly working space around the minithoracotomy working port, the positioning of the shaft is difficult and there is an implicit risk of chest wall bleeding. On the other hand, the trans-working-port type provides excellent exposure, is easily handled and manipulated, and facilitates surgeries involving various anatomical structures without special training. A great deal of understanding and knowledge about retractors is necessary to achieve the optimal exposure required to facilitate surgical techniques, and to maintain a reproducible and safe surgical system during mitral valve surgery.

  8. [Deformity of the cardiac structures in patients with mitral valve prolapse: the relationship with flat chest].

    PubMed

    Sunami, Y; Shimura, A; Miyazawa, Y; Nishimoto, Y; Masuda, Y; Inagaki, Y

    1988-01-01

    In view of the close relationship of mitral valve prolapse (MVP) and chest deformity, seven patients of MVP associated with flat chest were echocardiographically evaluated, and the results were compared with those of 43 normal control subjects, 29 cases with flat chest, and patients with MVP either of the an