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Sample records for disc mechanical mitral

  1. Mechanics of the mitral valve

    PubMed Central

    Rausch, Manuel K.; Famaey, Nele; Shultz, Tyler O’Brien; Bothe, Wolfgang; Miller, D. Craig

    2013-01-01

    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 119,021kPa at 0% prestrain via 36kPa at 30% prestrain to 9kPa 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. PMID:23263365

  2. 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

  3. 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

  4. 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. PMID:26483167

  5. Mechanics of the mitral valve strut chordae insertion region.

    PubMed

    Padala, Muralidhar; Sacks, Michael S; Liou, Shasan W; Balachandran, Kartik; He, Zhaoming; Yoganathan, Ajit P

    2010-08-01

    Interest in developing durable mitral valve repair methods is growing, underscoring the need to better understand the native mitral valve mechanics. In this study, the authors investigate the dynamic deformation of the mitral valve strut chordae-to-anterior leaflet transition zone using a novel stretch mapping method and report the complex mechanics of this region for the first time. Eight structurally normal porcine mitral valves were studied in a pulsatile left heart simulator under physiological hemodynamic conditions -120 mm peak transvalvular pressure, 5 l/min cardiac output at 70 bpm. The chordal insertion region was marked with a structured array of 31 miniature markers, and their motions throughout the cardiac cycle were tracked using two high speed cameras. 3D marker coordinates were calculated using direct linear transformation, and a second order continuous surface was fit to the marker cloud at each time frame. Average areal stretch, principal stretch magnitudes and directions, and stretch rates were computed, and temporal changes in each parameter were mapped over the insertion region. Stretch distribution was heterogeneous over the entire strut chordae insertion region, with the highest magnitudes along the edges of the chordal insertion region and the least along the axis of the strut chordae. At early systole, radial stretch was predominant, but by mid systole, significant stretch was observed in both radial and circumferential directions. The compressive stretches measured during systole indicate a strong coupling between the two principal directions, explaining the small magnitude of the systolic areal stretch. This study for the first time provides the dynamic kinematics of the strut chordae insertion region in the functioning mitral valve. A heterogeneous stretch pattern was measured, with the mechanics of this region governed by the complex underlying collagen architecture. The insertion region seemed to be under stretch during both systole and

  6. Surgical treatment of early acute thrombosis of mechanical mitral prosthesis.

    PubMed

    Jiang, Shengli; Zhang, Tao; Ren, Chonglei; Wang, Yao

    2010-10-01

    Prosthetic valve thrombosis is a rare but life threatening complication of mechanical heart valve prosthesis. A 44-year-old woman diagnosed with rheumatic heart disease with severe mitral valve stenosis, moderate tricuspid valve insufficiency, and atrial fibrillation underwent transseptal mitral valve replacement and tricuspid valvuloplasty in our department. Heparin and warfarin were routinely used postoperatively. Although the international normalized ratio (INR), activated partial thromboplastin time ratio, and platelet count were satisfactory, the patient presented with severe dyspnea suddenly 10 days after discharge; echocardiogram showed that the prosthetic posterior leaflet was immobile. The patient suffered cardiac arrest suddenly during the examination and cardiopulmonary resuscitation was carried out successfully. Emergent surgery was performed, confirming the prosthetic valve thrombosis. The prosthetic valve was replaced with another mechanical prosthesis. The patient recovered smoothly and was discharged 14 days later with atrial fibrillation. During the 12-months follow-up period, her prosthetic valve and heart function were normal with INR around 3.0. This case highlights the need for awareness among clinicians for the possibility of valve thrombosis in the early postoperative period. PMID:20961833

  7. Shear Mechanics of the TMJ Disc

    PubMed Central

    Juran, C.M.; Dolwick, M.F.; McFetridge, P.S.

    2012-01-01

    The temporomandibular joint (TMJ) is a complex hinge and gliding joint that induces significant shear loads onto the fibrocartilage TMJ disc during jaw motion. The purpose of this study was to assess regional variation in the disc’s shear loading characteristics under physiologically relevant loads and to associate those mechanical findings with common clinical observations of disc fatigue and damage. Porcine TMJ discs were compressed between an axially translating bottom platen and a 2.5-cm-diameter indenter within a hydrated testing chamber. Discs were cyclically sheared at 0.5, 1, or 5 Hz to 1, 3, or 5% shear strain. Within the anterior and intermediate regions of the disc when sheared in the anteroposterior direction, both shear and compressive moduli experienced a significant decrease from instantaneous to steady state, while the posterior region’s compressive modulus decreased approximately 5%, and no significant loss of shear modulus was noted. All regions retained their shear modulus within 0.5% of instantaneous values when shear was applied in the mediolateral direction. The results of the disc’s regional shear mechanics suggest an observable and predictable link with the common clinical observation that the posterior region of the disc is most often the zone in which fatigue occurs, which may lead to disc damage and perforation. PMID:23166043

  8. Retrograde Transcatheter Closure of Mitral Paravalvular Leak through a Mechanical Aortic Valve Prosthesis: 2 Successful Cases

    PubMed Central

    Zhou, Daxin; Pan, Wenzhi; Guan, Lihua; Qian, Juying

    2016-01-01

    The presence of a mechanical aortic valve prosthesis has been considered a contraindication to retrograde percutaneous closure of mitral paravalvular leaks, because passing a catheter through the mechanical aortic valve can affect the function of a mechanical valve and thereby lead to severe hemodynamic deterioration. We report what we believe are the first 2 cases of retrograde transcatheter closure of mitral paravalvular leaks through a mechanical aortic valve prosthesis without transseptal or transapical puncture. Our experience shows that retrograde transcatheter closure of mitral paravalvular leaks in this manner can be an optional approach for transcatheter closure of such leaks, especially when a transapical or transseptal puncture approach is not feasible. This technique might also be applied to other transcatheter procedures in which there is a need to pass a catheter through a mechanical aortic valve prosthesis. PMID:27127428

  9. Achieved Anticoagulation vs Prosthesis Selection for Mitral Mechanical Valve Replacement

    PubMed Central

    Le Tourneau, Thierry; Lim, Vanessa; Inamo, Jocelyn; Miller, Fletcher A.; Mahoney, Douglas W.; Schaff, Hartzell V.; Enriquez-Sarano, Maurice

    2009-01-01

    Background: Thromboembolic events (TEs) are frequent after mechanical mitral valve replacement (MVR), but their association to anticoagulation quality is unclear and has never been studied in a population-based setting with patients who have a complete anticoagulation record. Methods: We compiled a complete record of all residents of Olmsted County, MN, who underwent mechanical MVR between 1981 and 2004, for all TE, bleeding episodes, and international normalized ratios (INRs) measured from prosthesis implantation. Results: In the 112 residents (mean [± SD] age, 57 ± 16 years; 60% female residents) who underwent mechanical MVR, 19,647 INR samples were obtained. While INR averaged 3.02 ± 0.57, almost 40% of INRs were < 2 or > 4.5. Thirty-four TEs and 28 bleeding episodes occurred during a mean duration of 8.2 ± 6.1 years of follow-up. There was no trend of association of INR (average, SD, growth variance rate, or intensity-specific incidence of events) with TE. Previous cardiac surgery (p = 0.014) and ball prosthesis (hazard ratio [HR], 2.92; 95% CI, 1.43 to 5.94; p = 0.003) independently determined TE. With MVR using a ball prosthesis, despite higher anticoagulation intensity (p = 0.002), the 8-year rate of freedom from TE was considerably lower (50 ± 9% vs 81 ± 5%, respectively; p < 0.0001). Compared with expected stroke rates in the population, stroke risk was elevated with non-ball prosthesis MVR (HR 2.6; 95% CI, 1.3 to 5.2; p = 0.007) but was considerable with ball prosthesis MVR (HR 11.7; 95% CI, 7.5 to 18.4; p < 0.0001). INR variability (SD) was higher with a higher mean INR value (p < 0.0001). INR variability (HR 2.485; 95% CI, 1.11 to 5.55; p = 0.027) and cancer history (p < 0.0001) independently determined bleeding rates. Conclusion: This population-based comprehensive study of anticoagulation and TE post-MVR shows that, in these closely anticoagulated patients, anticoagulation intensity was highly variable and not associated with TE incidence post

  10. 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. PMID:26307201

  11. First-in-man treatment of a degenerated mitral surgical valve with the mechanical expanding Lotus™ valve.

    PubMed

    Schaefer, Ulrich; Conradi, Lenard; Lubos, Edith; Deuschl, Florian; Schofer, Niklas; Treede, Hendrik; Schirmer, Johannes; Vogel, Beatrice; Reichenspurner, Hermann; Blankenberg, Stefan

    2016-07-20

    Percutaneous placement of transcatheter heart valves for treatment of degenerated surgical valves in the aortic and mitral position is an emerging therapy for selected high-risk patients. Here we describe in detail the first case in the literature of a patient (female, 72 years old, log EuroSCORE 22.9%) with a degenerated biological mitral prosthesis which was successfully treated by transapical implantation of a Lotus valve. The case described demonstrates the very controlled feasibility of valve-in-valve treatment for a degenerated mitral bioprosthesis with a mechanically expanding Lotus valve. PMID:26348679

  12. Transcatheter ACURATE-TA Aortic Valve Implantation in a Patient With a Previous Mechanical Mitral Valve.

    PubMed

    Bagur, Rodrigo; Kiaii, Bob; Teefy, Patrick J; Diamantouros, Pantelis; Harle, Christopher; Goela, Aashish; Chan, Ian; Chu, Michael W A

    2015-11-01

    Transcatheter aortic valve implantation (TAVI) in the presence of a mechanical mitral valve (MMV) prosthesis is still challenging because of the rigid mitral frame within the aortomitral curtain. Moreover, low-lying coronary ostia represent a hazardous problem of coronary obstruction, especially in narrow or porcelain aortic roots. The present case demonstrates the successful management of 2 challenging anatomical issues, the rigid cage of the MMV and the low-lying left main coronary ostium (LMCO), with the implantation of the ACURATE-TA bioprosthesis (Symetis SA, Ecublens, Switzerland). It also highlights the importance of having multiple TAVI devices in order to choose the ideal transcatheter aortic bioprosthesis to fit the unique anatomical presentation of the patient. PMID:26522576

  13. 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

  14. Mitral stenosis

    MedlinePlus

    Mitral valve obstruction ... left side of your heart is called the mitral valve. It opens up enough so that blood can ... adults. These include: Calcium deposits forming around the mitral valve Radiation treatment to the chest Some medications Children ...

  15. Floppy mitral valve/mitral valve prolapse/mitral valvular regurgitation: effects on the circulation.

    PubMed

    Boudoulas, H; Wooley, C F

    2001-01-01

    The floppy mitral valve prolapses into the left atrium in such a dynamic manner that the prolapsing floppy mitral valve becomes a space-occupying lesion within the left atrium. A significant result of the floppy mitral valve prolapsing into the left atrium during left ventricular systole is the development of a "third chamber" located between the mitral annulus and the prolapsing mitral valve leaflets. Since the blood in the third chamber does not contribute to forward stroke volume, the third chamber may have significant effects on stroke volume and cardiac output. The floppy mitral valve/mitral valve prolapse dynamics also affect left ventricular papillary muscle tension and traction, altering the patterns of left ventricular contraction and relaxation, activating papillary muscle and left ventricular stretch receptors, and contributing to the production of cardiac arrhythmias. Floppy mitral valve innervation patterns with distinct nerve terminals provide a neural basis for brain-heart interactions, augmented by mechanical stimuli from the prolapsing floppy mitral valve. With the onset of mitral valvular regurgitation, and gradual progression of the mitral valve regurgitation from mild, to moderate, to severe, alterations in left atrial and left ventricular chamber size and performance occur, resulting in left atrial and left ventricular myopathy. As a connective tissue disorder, floppy mitral valve/mitral valve prolapse may be associated with abnormal structural and elastic properties of the aorta, with resultant changes in aortic function. Progression of mitral valve regurgitation and the aging process also affect aortic function indices in an adverse manner. The phenomena associated with floppy mitral valve dysfunction, with prolapse of the mitral valve into the left atrium and the unique, resultant forms of mitral valve regurgitation, are dynamic in nature. As the long-term natural history of these interrelated phenomena is being clarified, it is apparent

  16. Dynamic Compression Effects on Intervertebral Disc Mechanics and Biology

    PubMed Central

    Korecki, Casey L.; MacLean, Jeffrey J.; Iatridis, James C.

    2008-01-01

    Study Design A bovine intervertebral disc organ culture model was used to study the effect of dynamic compression magnitude on mechanical behavior and measurement of biosynthesis rate, cell viability, and mRNA expression. Objective The objective of this study was to examine the effect of loading magnitude on intervertebral disc mechanics and biology in an organ culture model. Summary of Background Data The in vivo and cell culture response of intervertebral disc cells to dynamic mechanical loading provides evidence the disc responds in a magnitude dependant manner. However, the ability to link mechanical behavior of the disc with biologic phenomena has been limited. A large animal organ culture system facilitates measurements of tissue mechanics and biologic response parameters on the same sample allowing a broader understanding of disc mechanobiology. Methods Bovine caudal intervertebral discs were placed in organ culture for 6 days and assigned to a static control or 1 of 2 dynamic compression loading protocols (0.2–1 MPa or 0.2–2.5 MPa) at 1 Hz for 1 hour for 5 days. Disc structure was assessed with measurements of dynamic modulus, creep, height loss, water content, and proteoglycan loss to the culture medium. Cellular responses were assessed through changes in cell viability, metabolism, and qRT-PCR analyses. Results Increasing magnitudes of compression increased disc modulus and creep; however, all mechanical parameters recovered each day. In the anulus, significant increases in gene expression for collagen I and a trend of increasing sulfate incorporation were observed. In the nucleus, increasing gene expression for collagen I and MMP3 was observed between magnitudes and between static controls and the lowest magnitude of loading. Conclusion Results support the hypothesis that biologic remodeling precedes damage to the intervertebral disc structure, that compression is a healthy loading condition for the disc, and further support the link between applied

  17. 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. PMID:15212921

  18. Echocardiographic Assessment of Ischaemic Mitral Regurgitation, Mechanism, Severity, Impact on Treatment Strategy and Long Term Outcome

    PubMed Central

    Naser, Nabil; Dzubur, Alen; Kusljugic, Zumreta; Kovacevic, Katarina; Kulic, Mehmed; Sokolovic, Sekib; Terzic, Ibrahim; Haxihibeqiri-Karabdic, Ilirijana; Hondo, Zorica; Brdzanovic, Snjezana; Miseljic, Sanja

    2016-01-01

    Introduction: The commonest mitral regurgitation etiologies are degenerative (60%), rheumatic post-inflammatory, 12%) and functional (25%). Due to the large number of patients with acute MI, the incidence of ischaemic MR is also high. Ischaemic mitral regurgitation is a complex multifactorial disease that involves left ventricular geometry, the mitral annulus, and the valvular/subvalvular apparatus. Ischaemic mitral regurgitation is an important consequence of LV remodeling after myocardial infarction. Research Objectives: The objective of this study is to determine the role of echocardiography in detecting and assessment of mitral regurgitation mechanism, severity, impact on treatment strategy and long term outcome in patients with myocardial infarction during the follow up period of 5 years. Also one of objectives to determine if the absence or presence of ischaemic MR is associated with increased morbidity and mortality in patients with myocardial infarction. Patients and methods: The study covered 138 adult patients. All patients were subjected to echocardiography evaluation after acute myocardial infarction during the period of follow up for 5 years. The patients were examined on an ultrasound machine Philips iE 33 xMatrix, Philips HD 11 XE, and GE Vivid 7 equipped with all cardiologic probes for adults and multi-plan TEE probes. We evaluated mechanisms and severity of mitral regurgitation which includes the regurgitant volume (RV), effective regurgitant orifice area (EROA), the regurgitant fraction (RF), Jet/LA area, also we measured the of vena contracta width (VC width cm) for assessment of IMR severity, papillary muscles anatomy and displacement, LV systolic function ± dilation, LV regional wall motion abnormality WMA, LV WMI, Left ventricle LV remodeling, impact on treatment strategy and long term mortality. Results: We analyzed and follow up 138 patients with previous (>16 days) Q-wave myocardial infarction by ECG who underwent TTE and TEE

  19. 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.

  20. Two mechanisms for dust gap opening in protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Dipierro, Giovanni; Laibe, Guillaume; Price, Daniel J.; Lodato, Giuseppe

    2016-06-01

    We identify two distinct physical mechanisms for dust gap opening by embedded planets in protoplanetary discs based on the symmetry of the drag-induced motion around the planet: (I) a mechanism where low-mass planets, that do not disturb the gas, open gaps in dust by tidal torques assisted by drag in the inner disc, but resisted by drag in the outer disc; and (II) the usual, drag-assisted, mechanism where higher mass planets create pressure maxima in the gas disc, which the drag torque then acts to evacuate further in the dust. The first mechanism produces gaps in dust but not gas, while the second produces partial or total gas gaps which are deeper in the dust phase. Dust gaps do not necessarily indicate gas gaps.

  1. A Novel Left Heart Simulator for the Multi-modality Characterization of Native Mitral Valve Geometry and Fluid Mechanics

    PubMed Central

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

    2012-01-01

    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. Threedimensional echocardiography was used to obtain systolic leaflet geometry for direct comparison of resultant leaflet kinematics. 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 was observed during peak systole, with minimal out-of-plane velocities (V~0.6m/s). 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, these data represent the first comprehensive database of high fidelity experimental data, critical for extensive validation of mitral valve fluid structure interaction simulations. PMID:22965640

  2. Molecular mechanisms of biological aging in intervertebral discs.

    PubMed

    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

    2016-08-01

    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. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1289-1306, 2016. PMID:26890203

  3. 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

  4. Mitral valve surgery - open

    MedlinePlus

    ... place. There are two types of mitral valves: Mechanical, made of man-made (synthetic) materials, such as ... Mechanical heart valves do not fail often. They last from 12 to 20 years. However, blood clots ...

  5. 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. PMID:26577235

  6. 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.

  7. Transvalvular mitral regurgitation following mitral valve replacement a diagnostic dilemma

    PubMed Central

    Kumar, U. S. Dinesh; Nareppa, Umesh; Shetty, Shyam Prasad; Wali, Murugesh

    2015-01-01

    After mitral valve replacement with a prosthetic valve, the valve should be competent and there should not be any residual prosthetic valve regurgitation. Transvalvular residual prosthetic valve regurgitation are difficult to diagnose and quantify. we are reporting interesting TEE images as a diagnostic dilemma in a case of transvalvular mitral regurgitation following mitral valve replacement secondary to entrapment of sub-valvular apparatus in a Chitra mechanical heart valve. PMID:26440249

  8. Proteoglycan expression is influenced by mechanical load in TMJ discs.

    PubMed

    Nakao, Y; Konno-Nagasaka, M; Toriya, N; Arakawa, T; Kashio, H; Takuma, T; Mizoguchi, I

    2015-01-01

    The expression and assembly of the extracellular matrix are profoundly associated with adaptive and pathological responses of the temporomandibular joint (TMJ). To better understand the adaptive responses of the TMJ disc to mechanical loading, we examined the expression of 2 modular proteoglycans and 10 small leucine-rich proteoglycans (SLRPs) at the mRNA and protein levels and determined the contents of proteoglycan-related glycosaminoglycans (GAGs) in rat TMJ discs in response to altered mechanical loading caused by an incisal bite plane. One hundred thirty 7-week-old male Wistar rats were assigned to control and bite plane groups. TMJ disc thickness and the intensity of toluidine blue staining of metachromasia increased in the posterior band after 2 weeks of wearing the bite plane. GAG content increased significantly in the bite plane group after 2 weeks. Quantitative real-time RT-PCR (reverse transcription polymerase chain reaction) analysis indicated that biglycan and chondroadherin mRNA levels increased after 2 weeks and that the level of decorin mRNA increased at 4 weeks. Versican mRNA levels increased after 3 weeks, particularly for the V0 and V1 versican isoforms, which carry more GAG attachment sites than do the V2 and V3 isoforms. Western analysis demonstrated a corresponding increase in the levels of versican, biglycan, and decorin core proteins at 4 weeks in the bite plane group. These results indicate that mechanical loading differentially influences proteoglycan mRNA expression and protein accumulation in the TMJ disc. The change in proteoglycan mRNA and protein levels may lead to the modulation of matrix-matrix and cell-matrix interactions and has important biological significance for adaptation to complicated biomechanical requirements and for tissue maintenance in the TMJ disc. PMID:25348543

  9. Advances in catheter ablation: atrial fibrillation ablation in patients with mitral mechanical prosthetic valve.

    PubMed

    Santangeli, Pasquale; Di Biase, Luigi; Bai, Rong; Horton, Rodney; Burkhardt, J David; Sanchez, Javier; Price, Justin; Natale, Andrea

    2012-11-01

    Atrial fibrillation (AF) is common in patients with mitral valve replacement (MVR). Treatment of AF in these subjects is challenging, as the arrhythmia is often refractory to antiarrhythmic drug therapy. Radiofrequency catheter ablation (RFCA) is usually avoided or delayed in patients with MVR due to the higher perceived risks and difficulty of left atrial catheter manipulation in the presence of a mechanical valve. Over the last few years, several investigators have reported the feasibility and safety of RFCA of AF in patients with MVR. Five case-control studies have evaluated the feasibility and safety of RFCA of AF or perimitral flutter (PMFL) in patients with MVR. Overall, a total of 178 patients with MVR have been included (21 undergoing ablation of only PMFL), and have been compared with a matched control group of 285 patients. Total procedural duration (weighted mean difference [WMD] = +24.5 min, 95% confidence interval [CI] +10.2 min to +38.8 min, P = 0.001), and fluoroscopy time (WMD = +13.5 min, 95% CI +3.7 min to +23.4 min, P = 0.007) were longer in the MVR group. After a mean follow-up of 11.5 ± 8.6 months, 64 (36%) patients in the MVR group experienced recurrence of AF/PMFL, as compared to 73 (26%) patients in the control group, accounting for a trend toward an increased rate of recurrences in patients with MVR (odds ratio [OR] = 1.66, 95% CI 0.99 to 2.78, P = 0.053). Periprocedural complications occurred in 10 (5.6%) patients in the MVR group, and in 8 (2.8%) patients in the control group (OR = 2.01, 95% CI 0.56 to 7.15, P = 0.28). In conclusion, a quantitative analysis of the available evidence supports a trend toward a worse arrhythmia-free survival and a higher absolute rate of periprocedural complications in patients with MVR undergoing RFCA of AF or PMFL, as compared to a matched control group without mitral valve disease. These data would encourage the adoption of RFCA of AF in MVR patients mostly by more experienced Institutions. PMID:23003204

  10. 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

  11. 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 ...

  12. Discs of mammalian rod photoreceptors form through the membrane evagination mechanism

    PubMed Central

    Ding, Jin-Dong; Salinas, Raquel Y.

    2015-01-01

    Photoreceptor discs are membrane organelles harboring components of the visual signal transduction pathway. The mechanism by which discs form remains enigmatic and is the subject of a major controversy. Classical studies suggest that discs are formed as serial plasma membrane evaginations, whereas a recent alternative postulates that discs, at least in mammalian rods, are formed through intracellular vesicular fusion. We evaluated these models in mouse rods using methods that distinguish between the intracellular vesicular structures and plasma membrane folds independently of their appearance in electron micrographs. The first differentiated membranes exposed to the extracellular space from intracellular membranes; the second interrogated the orientation of protein molecules in new discs. Both approaches revealed that new discs are plasma membrane evaginations. We further demonstrated that vesiculation and plasma membrane enclosure at the site of new disc formation are artifacts of tissue fixation. These data indicate that all vertebrate photoreceptors use the evolutionary conserved membrane evagination mechanism to build their discs. PMID:26527746

  13. Transient and sustained afterdepolarizations in accessory olfactory bulb mitral cells are mediated by distinct mechanisms that are differentially regulated by neuromodulators

    PubMed Central

    Shpak, Guy; Zylbertal, Asaph; Wagner, Shlomo

    2015-01-01

    Social interactions between mammalian conspecifics rely heavily on molecular communication via the main and accessory olfactory systems. These two chemosensory systems show high similarity in the organization of information flow along their early stages: social chemical cues are detected by the sensory neurons of the main olfactory epithelium and the vomeronasal organ. These neurons then convey sensory information to the main (MOB) and accessory (AOB) olfactory bulbs, respectively, where they synapse upon mitral cells that project to higher brain areas. Yet, the functional difference between these two chemosensory systems remains unclear. We have previously shown that MOB and AOB mitral cells exhibit very distinct intrinsic biophysical properties leading to different types of information processing. Specifically, we found that unlike MOB mitral cells, AOB neurons display persistent firing responses to strong stimuli. These prolonged responses are mediated by long-lasting calcium-activated non-selective cationic current (Ican). In the current study we further examined the firing characteristics of these cells and their modulation by several neuromodulators. We found that AOB mitral cells display transient depolarizing afterpotentials (DAPs) following moderate firing. These DAPs are not found in MOB mitral cells that show instead robust hyperpolarizing afterpotentials. Unlike Ican, the DAPs of AOB mitral cells are activated by low levels of intracellular calcium and are relatively insensitive to flufenamic acid. Moreover, the cholinergic agonist carbachol exerts opposite effects on the persistent firing and DAPs of AOB mitral cells. We conclude that these phenomena are mediated by distinct biophysical mechanisms that may serve to mediate different types of information processing in the AOB at distinct brain states. PMID:25642164

  14. Transient and sustained afterdepolarizations in accessory olfactory bulb mitral cells are mediated by distinct mechanisms that are differentially regulated by neuromodulators.

    PubMed

    Shpak, Guy; Zylbertal, Asaph; Wagner, Shlomo

    2014-01-01

    Social interactions between mammalian conspecifics rely heavily on molecular communication via the main and accessory olfactory systems. These two chemosensory systems show high similarity in the organization of information flow along their early stages: social chemical cues are detected by the sensory neurons of the main olfactory epithelium and the vomeronasal organ. These neurons then convey sensory information to the main (MOB) and accessory (AOB) olfactory bulbs, respectively, where they synapse upon mitral cells that project to higher brain areas. Yet, the functional difference between these two chemosensory systems remains unclear. We have previously shown that MOB and AOB mitral cells exhibit very distinct intrinsic biophysical properties leading to different types of information processing. Specifically, we found that unlike MOB mitral cells, AOB neurons display persistent firing responses to strong stimuli. These prolonged responses are mediated by long-lasting calcium-activated non-selective cationic current (Ican). In the current study we further examined the firing characteristics of these cells and their modulation by several neuromodulators. We found that AOB mitral cells display transient depolarizing afterpotentials (DAPs) following moderate firing. These DAPs are not found in MOB mitral cells that show instead robust hyperpolarizing afterpotentials. Unlike Ican, the DAPs of AOB mitral cells are activated by low levels of intracellular calcium and are relatively insensitive to flufenamic acid. Moreover, the cholinergic agonist carbachol exerts opposite effects on the persistent firing and DAPs of AOB mitral cells. We conclude that these phenomena are mediated by distinct biophysical mechanisms that may serve to mediate different types of information processing in the AOB at distinct brain states. PMID:25642164

  15. 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

  16. Molecular mechanisms of cell death in intervertebral disc degeneration (Review)

    PubMed Central

    ZHANG, FAN; ZHAO, XUELING; SHEN, HONGXING; ZHANG, CAIGUO

    2016-01-01

    Intervertebral discs (IVDs) are complex structures that consist of three parts, namely, nucleus pulposus, annulus fibrosus and cartilage endplates. With aging, IVDs gradually degenerate as a consequence of many factors, such as microenvironment changes and cell death. Human clinical trial and animal model studies have documented that cell death, particularly apoptosis and autophagy, significantly contribute to IVD degeneration. The mechanisms underlying this phenomenon include the activation of apoptotic pathways and the regulation of autophagy in response to nutrient deprivation and multiple stresses. In this review, we briefly summarize recent progress in understanding the function and regulation of apoptosis and autophagy signaling pathways. In particular, we focus on studies that reveal the functional mechanisms of these pathways in IVD degeneration. PMID:27121482

  17. Molecular mechanisms of cell death in intervertebral disc degeneration (Review).

    PubMed

    Zhang, Fan; Zhao, Xueling; Shen, Hongxing; Zhang, Caiguo

    2016-06-01

    Intervertebral discs (IVDs) are complex structures that consist of three parts, namely, nucleus pulposus, annulus fibrosus and cartilage endplates. With aging, IVDs gradually degenerate as a consequence of many factors, such as microenvironment changes and cell death. Human clinical trial and animal model studies have documented that cell death, particularly apoptosis and autophagy, significantly contribute to IVD degeneration. The mechanisms underlying this phenomenon include the activation of apoptotic pathways and the regulation of autophagy in response to nutrient deprivation and multiple stresses. In this review, we briefly summarize recent progress in understanding the function and regulation of apoptosis and autophagy signaling pathways. In particular, we focus on studies that reveal the functional mechanisms of these pathways in IVD degeneration. PMID:27121482

  18. High mechanical strain of primary intervertebral disc cells promotes secretion of inflammatory factors associated with disc degeneration and pain

    PubMed Central

    2014-01-01

    Introduction Excessive mechanical loading of intervertebral discs (IVDs) is thought to alter matrix properties and influence disc cell metabolism, contributing to degenerative disc disease and development of discogenic pain. However, little is known about how mechanical strain induces these changes. This study investigated the cellular and molecular changes as well as which inflammatory receptors and cytokines were upregulated in human intervertebral disc cells exposed to high mechanical strain (HMS) at low frequency. The impact of these metabolic changes on neuronal differentiation was also explored to determine a role in the development of disc degeneration and discogenic pain. Methods Isolated human annulus fibrosus (AF) and nucleus pulposus (NP) cells were exposed to HMS (20% cyclical stretch at 0.001 Hz) on high-extension silicone rubber dishes coupled to a mechanical stretching apparatus and compared to static control cultures. Gene expression of Toll-like receptors (TLRs), neuronal growth factor (NGF) and tumour necrosis factor α (TNFα) was assessed. Collected conditioned media were analysed for cytokine content and applied to rat pheocromocytoma PC12 cells for neuronal differentiation assessment. Results HMS caused upregulation of TLR2, TLR4, NGF and TNFα gene expression in IVD cells. Medium from HMS cultures contained elevated levels of growth-related oncogene, interleukin 6 (IL-6), IL-8, IL-15, monocyte chemoattractant protein 1 (MCP-1), MCP-3, monokine induced by γ interferon, transforming growth factor β1, TNFα and NGF. Exposure of PC12 cells to HMS-conditioned media resulted in both increased neurite sprouting and cell death. Conclusions HMS culture of IVD cells in vitro drives cytokine and inflammatory responses associated with degenerative disc disease and low-back pain. This study provides evidence for a direct link between cellular strain, secretory factors, neoinnervation and potential degeneration and discogenic pain in vivo. PMID:24457003

  19. 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

  20. Shear mechanics of the TMJ disc: relationship to common clinical observations.

    PubMed

    Juran, C M; Dolwick, M F; McFetridge, P S

    2013-02-01

    The temporomandibular joint (TMJ) is a complex hinge and gliding joint that induces significant shear loads onto the fibrocartilage TMJ disc during jaw motion. The purpose of this study was to assess regional variation in the disc's shear loading characteristics under physiologically relevant loads and to associate those mechanical findings with common clinical observations of disc fatigue and damage. Porcine TMJ discs were compressed between an axially translating bottom platen and a 2.5-cm-diameter indenter within a hydrated testing chamber. Discs were cyclically sheared at 0.5, 1, or 5 Hz to 1, 3, or 5% shear strain. Within the anterior and intermediate regions of the disc when sheared in the anteroposterior direction, both shear and compressive moduli experienced a significant decrease from instantaneous to steady state, while the posterior region's compressive modulus decreased approximately 5%, and no significant loss of shear modulus was noted. All regions retained their shear modulus within 0.5% of instantaneous values when shear was applied in the mediolateral direction. The results of the disc's regional shear mechanics suggest an observable and predictable link with the common clinical observation that the posterior region of the disc is most often the zone in which fatigue occurs, which may lead to disc damage and perforation. PMID:23166043

  1. 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. PMID:25737589

  2. Mechanisms of Functional Mitral Regurgitation in Ischemic Cardiomyopathy Determined by Transesophageal Echocardiography (From the Surgical Treatment for Ischemic Heart Failure [STICH] Trial)

    PubMed Central

    Golba, Krzysztof; Mokrzycki, Krzysztof; Drozdz, Jaroslaw; Cherniavsky, Alexander; Wrobel, Krzysztof; Roberts, Bradley J.; Haddad, Haissam; Maurer, Gerald; Yii, Michael; Asch, Federico M.; Handschumacher, Mark D.; Holly, Thomas A.; Przybylski, Roman; Kron, Irving; Schaff, Hartzell; Aston, Susan; Horton, John; Lee, Kerry L.; Velazquez, Eric J.; Grayburn, Paul A.

    2013-01-01

    The mechanisms underlying functional mitral regurgitation (MR), and the relation between mechanism and severity of MR have not been evaluated in a large multicenter randomized controlled trial. Transesophageal echocardiography (TEE) was performed in 215 patients at 17 centers in the Surgical Treatment of Ischemic Heart Failure (STICH) trial. Both two-dimensional (2D, n=215) and three-dimensional (3D, n=81) TEE were used to assess multiple quantitative measures of the mechanism and severity of MR. By 2D TEE, leaflet tenting area, anterior and posterior leaflet angles, mitral annulus diameter, left ventricular (LV) end-systolic volume index, LV ejection fraction (LVEF), and sphericity index (p<0.05 for all) were significantly different across MR grades. By 3D TEE, mitral annulus area, leaflet tenting area, LV end-systolic volume index, LVEF, and sphericity index (p<0.05 for all) were significantly different across MR grades. A multivariable analysis showed a trend for annulus area (p=0.069) and LV end-systolic volume index (p=0.071) to predict effective regurgitant orifice area (EROA) and for annulus area (p=0.018) and LV end-systolic volume index (p=0.073) to predict vena contracta area. In the STICH trial, multiple quantitative parameters of the mechanism of functional MR are related to MR severity. The mechanism of functional MR in ischemic cardiomyopathy is heterogeneous but no single variable stands out as a strong predictor of quantitative severity of MR. PMID:24035166

  3. Temporal changes of mechanical signals and extracellular composition in human intervertebral disc during degenerative progression

    PubMed Central

    Zhu, Qiaoqiao; Gao, Xin; Gu, Weiyong

    2014-01-01

    In this study, a three-dimensional finite element model was used to investigate the changes in tissue composition and mechanical signals within human lumbar intervertebral disc during the degenerative progression. This model was developed based on the cell-activity coupled mechano-electrochemical mixture theory. The disc degeneration was simulated by lowering nutrition levels at disc boundaries, and the temporal and spatial distributions of the fixed charge density, water content, fluid pressure, Von Mises stress, and disc deformation were analyzed. Results showed that fixed charge density, fluid pressure, and water content decreased significantly in the nucleus pulposus (NP) and the inner to middle annulus fibrosus (AF) regions of the degenerative disc. It was found that, with degenerative progression, the Von Mises stress (relative to that at healthy state) increased within the disc, with a larger increase in the outer AF region. Both the disc volume and height decreased with the degenerative progression. The predicted results of fluid pressure change in the NP were consistent with experimental findings in the literature. The knowledge of the variations of temporal and spatial distributions of composition and mechanical signals within the human IVDs provide a better understanding of the progression of disc degeneration. PMID:25305690

  4. Cells from Degenerative Intervertebral Discs Demonstrate Unfavorable Responses to Mechanical and Inflammatory Stimuli: A Pilot Study

    PubMed Central

    Sowa, Gwendolyn A.; Coelho, J. Paulo; Vo, Nam V.; Pacek, Corey; Westrick, Edward; Kang, James D.

    2016-01-01

    Objective Mechanical forces and inflammatory signaling influence intervertebral disc matrix homeostasis. We hypothesized that annulus fibrosus cells from degenerative discs would have altered responses to mechanical and inflammatory stimuli compared with cells isolated from normal discs. Design Annulus fibrosus cells were isolated from New Zealand White rabbits with normal and magnetic resonance imaging-confirmed degenerative discs created by annular stab. Cells were cultured with and without inflammatory and mechanical stimuli (tensile strain). After 4 or 24 hrs, the mRNA expression of inflammatory, catabolic, and anabolic genes was measured by reverse transcription polymerase chain reaction. Results Baseline gene expression differences were noted between cells from normal and degenerative discs. Degenerative cells demonstrated a more proinflammatory response profile to inflammatory and mechanical stimuli and loss of the beneficial effects of mechanical signaling. Decreased expression of catabolic and anabolic genes was observed in degenerative cells under conditions of inflammatory and mechanical stimuli. Conclusions These data demonstrate that degenerative cells have a decreased capacity to respond positively to beneficial levels of mechanical strain and demonstrate an exaggerated response to an inflammatory stimulus. This may, in part, help to explain differential responses to motion-based therapies in patients with intervertebral disc degeneration. PMID:22760106

  5. The effects of a low international normalized ratio on thromboembolic and bleeding complications in patients with mechanical mitral valve replacement

    PubMed Central

    2014-01-01

    Background Mechanical heart valve replacement has an inherent risk of thromboembolic events (TEs). Current guidelines recommend an international normalized ratio (INR) of at least 2.5 after mechanical mitral valve replacement (MVR). This study aimed to evaluate the effects of a low INR (2.0–2.5) on thromboembolic and bleeding complications in patients with mechanical MVR on warfarin therapy. Methods One hundred and thirty-five patients who underwent mechanical MVR were enrolled in this study. The end points of this study were defined as TEs (valve thrombosis, transient ischemic attack, stroke) and bleeding (all minor and major bleeding) complications. Patients were followed up for a mean of 39.6 months and the mean INR of the patients was calculated. After data collection, patients were divided into 3 groups according to their mean INR, as follows: group 1 (n = 34), INR <2.0; group 2 (n = 49), INR 2.0–2.5; and group 3 (n = 52), INR >2.5. Results A total of 22 events (10 [7.4%] thromboembolic and 12 [8.8%] bleeding events) occurred in the follow-up period. The mean INR was an independent risk factor for the development of TEs. Mean INR and neurological dysfunction were independent risk factors for the development of bleeding events. A statistically significant positive correlation was found between the log mean INR and all bleeding events, and a negative correlation was found between the log mean INR and all TEs. The total number of events was significantly lower in group 2 than in groups 1 and 3 (P = 0.036). Conclusions This study showed that a target INRs of 2.0–2.5 are acceptable for preventing TEs and safe in terms of bleeding complications in patients with mechanical MVR. PMID:24885719

  6. Patterns of systolic stress distribution on mitral valve anterior leaflet chordal apparatus. A structural mechanical theoretical analysis.

    PubMed

    Nazari, S; Carli, F; Salvi, S; Banfi, C; Aluffi, A; Mourad, Z; Buniva, P; Rescigno, G

    2000-04-01

    Increasing diffusion and complexity of mitral valve repair procedures may prompt an interest in the evaluation of the patterns of stress distribution on the chords, which are, from the structural mechanical point of view, the weakest element of valve apparatus. This theoretical analysis concentrates in particular on the mitral valve anterior leaflet. As is known, the vast majority of the chordae are attached to the anterior leaflet within the coaptation area; during systole they are then necessarily parallel, aligned along the same plane as that of the leaflets' coaptation surface, to which they are attached; moreover the thickness of the chordae increases significantly from the marginal chordae to the more central ones. In normal conditions during systole the progressively wider coaptation surface causes the increasing stress to be supported by an increasing number of progressively thicker chords, which are substantially parallel and aligned on the coaptation surface plane in such a way that they can share the stress between them, according to their thickness; in other words chords form a multifilament functional unit which enrolls elements of increasing thickness in response to the mounting stress. The geometrical modifications of the valve apparatus architecture (annulus dilatation, leaflet retraction, chordal elongation or retraction) often associated with valve insufficiency due to chordal rupture, have the common result of causing, during systole, a radial disarrangement of the direction of most of the secondary chordae which are no longer parallel, aligned on the coaptation surface plane. Due to the negligible elastic module of the valve leaflet, in this new arrangement the various chordae cannot share the stress between themselves as they do in a normal physiological situation; on the contrary the thinner chordae nearer to the free margin are also loaded with the peak systolic stress, thus generating conditions favoring their rupture. It can, therefore, be

  7. The effect of nucleus pulposus crosslinking and glycosaminoglycan degradation on disc mechanical function.

    PubMed

    Yerramalli, C S; Chou, A I; Miller, G J; Nicoll, S B; Chin, K R; Elliott, D M

    2007-01-01

    Altered mechanical loading, secondary to biochemical changes in the nucleus pulposus, is a potential mechanism in disc degeneration. An understanding of the role of this altered mechanical loading is only possible by separating the mechanical and biological effects of early nucleus pulposus changes. The objective of this study was to quantify the mechanical effect of decreased glycosaminoglycans (GAG) and increased crosslinking in the nucleus pulposus using in vitro rat lumbar discs. Following initial mechanical testing the discs were injected according to the four treatment groups: PBS control, chondroitinase-ABC (ChABC) for GAG degradation, genipin (Gen) for crosslinking, or a combination of chondroitinase and genipin (ChABC+Gen). After treatment the discs were again mechanically tested, followed by histology or biochemistry. Neutral zone mechanical properties were changed by approximately 20% for PBS, ChABC, and ChABC+Gen treatments (significant only for PBS in a paired comparison). These trends were reversed with genipin crosslinking alone. With ChABC treatment the effective compressive modulus increased and the GAG content decreased; with the combination of ChABC+Gen the mechanics and GAG content were unchanged. Degradation of nucleus pulposus GAG alters disc axial mechanics, potentially contributing to the degenerative cascade. Crosslinking is unlikely to contribute to degeneration, but may be a potential avenue of treatment. PMID:16715318

  8. [The influences of anterior disc displacement on oral mandibular function and morphology and their biological mechanisms].

    PubMed

    Xia, Wendi; Fu, Kiayuan

    2016-03-01

    Anterior disc displacement is a common subtype seen in temporomandibular disorders (TMD) patients. It may cause mandibular movement disorders, such as clicking of joint, intermittent closed lock, limitation of mouth opening, etc. These disorders may affect the life qualities of patients. Anterior disc displacement may also cause mandibular malformations, especially among adolescents, which may affect the growth of condyle, therefore may have a correlation with mandibular retrusion or mandibular deviation when grown up. This paper going to review the influences of anterior disc displacement on oral mandibular function and morphology and their biological mechanisms. PMID:26980658

  9. Mitral valve prolapse

    MedlinePlus

    ... Systolic click-murmur syndrome; Prolapsing mitral leaflet syndrome; Chest pain - mitral valve prolapse ... often affects thin women who may have minor chest wall deformities, scoliosis, or other disorders. Some forms ...

  10. Mitral Valve Prolapse

    MedlinePlus

    ... Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis ... Stroke Sudden Cardiac Arrest Valve Disease Vulnerable Plaque Mitral Valve Prolapse | Share Related terms: MVP, disease of the ...

  11. 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 ...

  12. Mitral Valve Disease

    MedlinePlus

    ... disease occurs when the mitral valve doesn’t work properly. Types of Mitral Valve Disease Types of ... until you are able to go back to work, depending on your job. Everyday activities such as ...

  13. [Caseous Calcification of Mitral Valve Annulus;Report of a Case].

    PubMed

    Izumoto, Hiroshi; Fukushima, Kenichi; Hayashi, Tomohiko; Hori, Yasuhiko; Takiguchi, Makoto; Murayama, Taichi; Suzuki, Masahiro; Komiyama, Nobuyuki; Ishihara, Kazuaki

    2016-07-01

    We report a case of an 80-year-old female presenting with a mitral valve tumor. Postoperatively, pathologic diagnosis was caseous calcification of the mitral annulus. In surgery, she successfully underwent a mitral valve replacement with a 20 mm mechanical valve. The importance of correctly making a preoperative diagnosis cannot be over-emphasized. Technical discussion on possibility of mitral valve repair and patient-prosthesis mismatch after mitral valve replacement is also made. PMID:27365066

  14. Lessons from the past: twenty-five years experience with the Cross-Jones caged disc prosthesis.

    PubMed

    Kovacs, G S; Felkai, B; Toszegi, A M

    1993-11-01

    One hundred and twenty-one patients who received 145 Cross-Jones prostheses between 1967 and 1973 were followed for over 20 years. Thirty-six patients had undergone single aortic valve replacement, receiving an uncovered prosthesis (Group A), while 83 of the 85 patients in Group B undergoing isolated mitral or combined mitral and aortic and/or tricuspid replacements received a cloth-covered prosthesis in the mitral and/or tricuspid position. There were no mechanical failures in Group A, and three patients are alive 24 years after their operations. The seat was smooth in all prostheses inspected at autopsy and the disc was not worn even 15-18 years after surgery. The overall incidence of thromboembolism in this group was 3.56%/pty, of which 2.13%/pty were fatal. All operative offvivors with cloth-covered valves developed mechanical dysfunction leading to death or requiring reoperation within ten years. The cloth cover was invariably disrupted and the disc hitting this rough surface had become worn, with significant diminution in their diameters in all valves recovered during reoperation or at autopsy. In seven patients, the disc escaped from a mitral prosthesis causing immediate death, while one patient survived a tricuspid disc escape for over one month and was then successfully reoperated. The overall incidence of thromboembolism in Group B was 23.4%/pty, of which 11.7%/pty were fatal. PMID:7719509

  15. Mitral Valve Replacement with Half-and-Half Technique for Recurrent Mitral Paravalvular Leakage.

    PubMed

    Morisaki, Akimasa; Kato, Yasuyuki; Takahashi, Yosuke; Shibata, Toshihiko

    2015-05-01

    Reoperation for paravalvular leakage can cause recurrent paravalvular leakage through severe damage to the mitral annulus. Previously, mitral valve replacement using a half-and-half technique for extensive mitral annular calcification was reported; here, application of the technique to treat recurrent paravalvular leakage is described. A 78-year-old male with three prior mitral valve replacements developed recurrent paravalvular leakage, for which he had undergone his third mitral valve replacement at the age of 69 years. On this occasion, a mechanical valve with circumferential equine pericardial patch reinforcement of the annulus had been used. Five years later, the patient developed hemolytic anemia and congestive heart failure due to recurrent paravalvular leakage. Intraoperatively, broad dehiscence was seen between the prosthetic valve and mitral annulus at two sites, the anterior and posterior commissures, without infection. A fourth mitral valve replacement was performed with a St. Jude Medical valve, using a half-and-half technique. This entailed the use of non-everting mattress sutures on the anterior half of the annulus, and everting mattress sutures on the left atrial wall around the posterior half of the annulus. Extensive annular defects required reinforcement of the posterior mitral annulus with a bovine pericardial patch. Postoperative echocardiography showed no paravalvular leakage. The half-and-half technique may be useful in treating recurrent paravalvular leakage of the mitral valve. PMID:26901904

  16. Percutaneous balloon dilatation of the mitral valve: an analysis of echocardiographic variables related to outcome and the mechanism of dilatation.

    PubMed Central

    Wilkins, G T; Weyman, A E; Abascal, V M; Block, P C; Palacios, I F

    1988-01-01

    Twenty two patients (four men, 18 women, mean age 56 years, range 21 to 88 years) with a history of rheumatic mitral stenosis were studied by cross sectional echocardiography before and after balloon dilatation of the mitral valve. The appearance of the mitral valve on the pre-dilatation echocardiogram was scored for leaflet mobility, leaflet thickening, subvalvar thickening, and calcification. Mitral valve area, left atrial volume, transmitral pressure difference, pulmonary artery pressure, cardiac output, cardiac rhythm, New York Heart Association functional class, age, and sex were also studied. Because there was some increase in valve area in almost all patients the results were classified as optimal or suboptimal (final valve area less than 1.0 cm2, final left atrial pressure greater than 10 mm Hg, or final valve area less than 25% greater than the initial area). The best multiple logistic regression fit was found with the total echocardiographic score alone. A high score (advanced leaflet deformity) was associated with a suboptimal outcome while a low score (a mobile valve with limited thickening) was associated with an optimal outcome. No other haemodynamic or clinical variables emerged as predictors of outcome in this analysis. Examination of pre-dilatation and post-dilatation echocardiograms showed that balloon dilatation reliably resulted in cleavage of the commissural plane and thus an increase in valve area. Images Fig 1 Fig 2 Fig 3 Fig 4 Fig 6 PMID:3190958

  17. 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

  18. 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. PMID:26416720

  19. Dependence of mechanical behavior of the murine tail disc on regional material properties: a parametric finite element study.

    PubMed

    Hsieh, Adam H; Wagner, Diane R; Cheng, Louis Y; Lotz, Jeffrey C

    2005-12-01

    In vivo rodent tail models are becoming more widely used for exploring the role of mechanical loading on the initiation and progression of intervertebral disc degeneration. Historically, finite element models (FEMs) have been useful for predicting disc mechanics in humans. However, differences in geometry and tissue properties may limit the predictive utility of these models for rodent discs. Clearly, models that are specific for rodent tail discs and accurately simulate the disc's transient mechanical behavior would serve as important tools for clarifying disc mechanics in these animal models. An FEM was developed based on the structure, geometry, and scale of the mouse tail disc. Importantly, two sources of time-dependent mechanical behavior were incorporated: viscoelasticity of the matrix, and fluid permeation. In addition, a novel strain-dependent swelling pressure was implemented through the introduction of a dilatational stress in nuclear elements. The model was then validated against data from quasi-static tension-compression and compressive creep experiments performed previously using mouse tail discs. Finally, sensitivity analyses were performed in which material parameters of each disc subregion were individually varied. During disc compression, matrix consolidation was observed to occur preferentially at the periphery of the nucleus pulposus. Sensitivity analyses revealed that disc mechanics was greatly influenced by changes in nucleus pulposus material properties, but rather insensitive to variations in any of the endplate properties. Moreover, three key features of the model-nuclear swelling pressure, lamellar collagen viscoelasticity, and interstitial fluid permeation-were found to be critical for accurate simulation of disc mechanics. In particular, collagen viscoelasticity dominated the transient behavior of the disc during the initial 2200 s of creep loading, while fluid permeation governed disc deformation thereafter. The FEM developed in this

  20. 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

  1. 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.

  2. 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.

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

    PubMed

    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

  4. 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

  5. [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. PMID:26907868

  6. 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

  7. Determination of mechanical stress distribution in Drosophila wing discs using photoelasticity.

    PubMed

    Nienhaus, Ulrike; Aegerter-Wilmsen, Tinri; Aegerter, Christof M

    2009-12-01

    Morphogenesis, the process by which all complex biological structures are formed, is driven by an intricate interplay between genes, growth, as well as intra- and intercellular forces. While the expression of different genes changes the mechanical properties and shapes of cells, growth exerts forces in response to which tissues, organs and more complex structures are shaped. This is exemplified by a number of recent findings for instance in meristem formation in Arabidopsis and tracheal tube formation in Drosophila. However, growth not only generates forces, mechanical forces can also have an effect on growth rates, as is seen in mammalian tissues or bone growth. In fact, mechanical forces can influence the expression levels of patterning genes, allowing control of morphogenesis via mechanical feedback. In order to study the connections between mechanical stress, growth control and morphogenesis, information about the distribution of stress in a tissue is invaluable. Here, we applied stress-birefringence to the wing imaginal disc of Drosophila melanogaster, a commonly used model system for organ growth and patterning, in order to assess the stress distribution present in this tissue. For this purpose, stress-related differences in retardance are measured using a custom-built optical set-up. Applying this method, we found that the stresses are inhomogeneously distributed in the wing disc, with maximum compression in the centre of the wing pouch. This compression increases with wing disc size, showing that mechanical forces vary with the age of the tissue. These results are discussed in light of recent models proposing mechanical regulation of wing disc growth. PMID:19748573

  8. Use of an Edwards Sapien S3 valve to replace a dysfunctional mechanical mitral valve in an 11-year old boy: another small step for surgical and interventional collaboration.

    PubMed

    Murphy, Michael; Austin, Conal; Bapat, Vinayak; Morgan, Gareth J

    2016-09-01

    An 11-year old boy, with complex left ventricular morphology in the setting of repaired double outlet right ventricle developed progressive mitral regurgitation leading to a repair which failed, necessitating replacement of the valve with a 21 mm St. Jude mechanical prosthesis. He represented 3 weeks later in extremis with signs of severe mitral stenosis. The valve was replaced via a hybrid technique with a 26 mm Edwards Sapien 3 valve mounted on a MEMO 3D annuloplasty ring. One year later, the valve is functioning well with no regurgitation or evidence of an inflow gradient. PMID:26994169

  9. Percutaneous Mitral Annuloplasty for Functional Mitral Regurgitation

    PubMed Central

    Schofer, Joachim; Siminiak, Tomasz; Haude, Michael; Herrman, Jean P.; Vainer, Jindra; Wu, Justina C.; Levy, Wayne C.; Mauri, Laura; Feldman, Ted; Kwong, Raymond Y.; Kaye, David M.; Duffy, Stephen J.; Tübler, Thilo; Degen, Hubertus; Brandt, Mathias C.; Van Bibber, Rich; Goldberg, Steve; Reuter, David G.; Hoppe, Uta C.

    2014-01-01

    Background Functional mitral regurgitation (FMR), a well-recognized component of left ventricular remodeling, is associated with increased morbidity and mortality in heart failure patients. Percutaneous mitral annuloplasty has the potential to serve as a therapeutic adjunct to standard medical care. Methods and Results Patients with dilated cardiomyopathy, moderate to severe FMR, an ejection fraction <40%, and a 6-minute walk distance between 150 and 450 m were enrolled in the CARILLON Mitral Annuloplasty Device European Union Study (AMADEUS). Percutaneous mitral annuloplasty was achieved through the coronary sinus with the CARILLON Mitral Contour System. Echocardiographic FMR grade, exercise tolerance, New York Heart Association class, and quality of life were assessed at baseline and 1 and 6 months. Of the 48 patients enrolled in the trial, 30 received the CARILLON device. Eighteen patients did not receive a device because of access issues, insufficient acute FMR reduction, or coronary artery compromise. The major adverse event rate was 13% at 30 days. At 6 months, the degree of FMR reduction among 5 different quantitative echocardiographic measures ranged from 22% to 32%. Six-minute walk distance improved from 307±87 m at baseline to 403±137 m at 6 months (P<0.001). Quality of life, measured by the Kansas City Cardiomyopathy Questionnaire, improved from 47±16 points at baseline to 69±15 points at 6 months (P<0.001). Conclusions Percutaneous reduction in FMR with a novel coronary sinus–based mitral annuloplasty device is feasible in patients with heart failure, is associated with a low rate of major adverse events, and is associated with improvement in quality of life and exercise tolerance. PMID:19597051

  10. 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'.

  11. Mitral valve repair versus replacement

    PubMed Central

    Keshavamurthy, Suresh; Gillinov, A. Marc

    2015-01-01

    Degenerative, ischemic, rheumatic and infectious (endocarditis) processes are responsible for mitral valve disease in adults. Mitral valve repair has been widely regarded as the optimal surgical procedure to treat mitral valve dysfunction of all etiologies. The supporting evidence for repair over replacement is strongest in degenerative mitral regurgitation. The aim of the present review is to summarize the data in each category of mitral insufficiency and to provide recommendations based upon this data. PMID:26309824

  12. Horseshoe thrombus in a patient with mechanical prosthetic mitral valve: A case report and review of literature

    PubMed Central

    Mehra, Sanjay; Movahed, Assad; Espinoza, Carlos; Marcu, Constantin B

    2015-01-01

    Patients with prosthetic cardiac valves are at high risk for thromboembolic complications and need life long anticoagulation with warfarin, which can be associated with variable dose requirements and fluctuating level of systemic anticoagulation and may predispose to thromboembolic and or hemorrhagic complications. Prosthetic cardiac valve thrombosis is associated with high morbidity and mortality. A high index of suspicion is essential for prompt diagnosis. Transthoracic echocardiography, and if required transesophageal echocardiography are the main diagnostic imaging modalities. Medically stable patients can be managed with thrombolytic therapy and anticoagulation, while some patients may require surgical thrombectomy or valve replacement. We present a case report of a patient with prosthetic mitral valve and an unusually large left atrial thrombus with both thromboembolic and hemorrhagic complications. PMID:26380832

  13. 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.

  14. Mechanical Control of Organ Size in the Development of the Drosophila Wing Disc

    PubMed Central

    Schluck, Thomas; Nienhaus, Ulrike; Aegerter-Wilmsen, Tinri; Aegerter, Christof M.

    2013-01-01

    Control of cessation of growth in developing organs has recently been proposed to be influenced by mechanical forces acting on the tissue due to its growth. In particular, it was proposed that stretching of the tissue leads to an increase in cell proliferation. Using the model system of the Drosophila wing imaginal disc, we directly stretch the tissue finding a significant increase in cell proliferation, thus confirming this hypothesis. In addition, we characterize the growth over the entire growth period of the wing disc finding a correlation between the apical cell area and cell proliferation rate. PACS numbers: 87.19.lx, 87.18.Nq, 87.80.Ek, 87.17.Ee, 87.85.Xd PMID:24204600

  15. 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

  16. Mitral stenosis (image)

    MedlinePlus

    ... that flows forward to the body. The main risk factor for mitral stenosis is a history of rheumatic fever but it may also be triggered by pregnancy or other stress on the body such as a respiratory infection, ...

  17. 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)

  18. DISC: A Novel Approach for Determining the Mechanical Properties of Skin

    NASA Astrophysics Data System (ADS)

    Guan, E.; Smilow, Sarah; Rafailovich, Miriam; Sokolov, Jonathan

    2003-03-01

    The non-contact, non-invasive, deformation measuring technique, digital image speckle correlation(DISC) has been successfully applied to the in vitro tensile tests of rat skin to study its mechanical properties and to the in vivo monitoring of elastic discontinuity of human skin. With the tensile tests, the Young's modulus and breaking strength of both fresh and processed samples were determined. It has been shown that the collagen-building cream used in this study can efficiently slow down the loss of elasticity of excised rat skin. The individual failure of dermal layers was observed during the tests of fresh skin samples. From its stress-strain curve, the highly non-linear, strain-toughening property of varying skin layers was found. The accuracy of the DISC method and the fact that it is a non-invasive technique can permit surgeons to monitor dermal abnormalities in situ during surgical procedures. By measuring correlated motions with high spatial resolution, the DISC method was shown to accurately detect regions of local paralysis and potential wrinkles, which are too small to be detected by the naked eye.

  19. Percutaneous laser lumbar disc decompression - mechanism of action, indications and contraindications.

    PubMed

    Maksymowicz, Wojciech; Barczewska, Monika; Sobieraj, Andrzej

    2004-06-30

    This article describes the development of minimally invasive methods in the treatment of lumbar discopathy, with particular attention to percutaneous laser disc decompression (PLDD). The authors discus the therapeutic operating mechanism of PLDD, emphasizing the importance of the thermal characteristics of laser light, which is responsible for the vaporization and ablation of a small amount of tissue from the nucleus pulposus. This causes a significant reduction in pressure in the closed structure of the disc, and consequently reduced compression exerted by the disk on the dural sac and the nerve roots. Improvement in the flow of cerebro-spinal fluid has also been observed on the level at which the operation is performed. On the basis of our own experience and the reports of other authors, we have specified indications and contra-indications for PLDD. Our conclusion is that PLDD is an effective treatment method for low back pain and ischialgia caused by protrusion or herniation of the nucleus pulposus, with elimination or significant reduction in symptoms in over 75% of those treated; reduction or resolution of neurological deficits that arise in the course of lumbar discopathy has also been observed. This method enables one-stage treatment of multi-level degenerative changes in the intervertebral disc. The only absolute contraindications for PLDD are the presence of sequestration, disturbances in blood coagulation, and bacterial infection. PMID:17675991

  20. 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. PMID:22015913

  1. Predictors of Very Late Events After Percutaneous Mitral Valvuloplasty in Patients With Mitral Stenosis.

    PubMed

    Jorge, Elisabete; Pan, Manuel; Baptista, Rui; Romero, Miguel; Ojeda, Soledad; Suárez de Lezo, Javier; Faria, Henrique; Calisto, João; Monteiro, Pedro; Pêgo, Mariano; Suárez de Lezo, José

    2016-06-15

    Data on long-term outcomes of percutaneous mitral valvuloplasty (PMV) are still scarce. In addition, the persistence of pulmonary hypertension (PH) after PMV is a complication for which mechanisms and prognostic implications are unclear. Our aims were (1) to report the long-term outcomes of patients with rheumatic mitral stenosis treated with PMV; (2) to determine the risk factors for long-term poor outcomes; and (3) to analyze the prevalence and predictors of persistent PH. We prospectively enrolled 532 patients who underwent PMV from 1987 to 2011 at 2 hospitals. The following end points were assessed after PMV: all-cause mortality, mitral reintervention, a composite end point of all-cause mortality and mitral reintervention, and PH persistence. Survival status was available for 97% patients; the median follow-up was 10 years (interquartile range 4 to 18 years). Procedural success was achieved in 85% patients. During the follow-up, 21% patients died and 27% required mitral reintervention. Before PMV, 74% patients had PH that persisted after PMV in 45% of patients (p <0.001). Unfavorable valve anatomy (Wilkins score >8) and post-PMV mean pulmonary arterial pressure (PAP) were independent predictors of all-cause mortality, mitral reintervention, and the composite end point. Post-PMV mean PAP was significantly correlated with a mitral valve area (MVA) <2.5 cm(2) (p <0.001); in addition, on the echocardiographic follow-up, MVA was an independent predictor of systolic PAP (p <0.001). In conclusion, PMV represents an advantageous therapeutic option for patients with mitral stenosis in terms of long-term outcomes. Unfavorable valve anatomy and persistent PH were the most important predictors of long-term outcomes. The persistence of PH is associated with the MVA obtained after PMV. PMID:27131615

  2. 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

  3. Mitral valve repair

    PubMed Central

    Pozzoli, Alberto; De Bonis, Michele; Alfieri, Ottavio

    2016-01-01

    Mitral regurgitation (MR) is the most common valvular heart disease in the Western world. The MR can be either organic (mainly degenerative in Western countries) or functional (secondary to left ventricular remodeling in the context of ischemic or idiopathic dilated cardiomyopathy). Degenerative and functional MR are completely different disease entities that pose specific decision-making problems and require different management. The natural history of severe degenerative MR is clearly unfavorable. However, timely and effective correction of degenerative MR is associated with a normalization of life expectancy. By contrast, the prognostic impact of the correction of functional MR is still debated and controversial. In this review, we discuss the optimal treatment of both degenerative and functional MR, taking into account current surgical and percutaneous options. In addition, since a clear understanding of the etiology and mechanisms of valvular dysfunction is important to guide the timing and choice of treatment, the role of the heart team and of echo imaging in the management of MR is addressed as well. PMID:27347389

  4. Mechanical properties of human lumbar spine motion segments. Influence of age, sex, disc level, and degeneration.

    PubMed

    Nachemson, A L; Schultz, A B; Berkson, M H

    1979-01-01

    The influences of age, sex, disc level, and degree of degenration on the mechanical behavior of 42 fresh cadaver lumbar motion segments are reported. The motions and intradiscal pressure changes that result from the application of flexion, extension, lateral bending, and torsional moments; compression; and anterior, posterior, and lateral shears are described. The authors find that the mean behaviors of the different segment classes sometimes differ, but these differences are seldom pronounced. Scatter in the behavior of individual motion segments is pronounced, and very often overshadows any class differences. PMID:432710

  5. The aging mouse partially models the aging human spine: lumbar and coccygeal disc height, composition, mechanical properties, and Wnt signaling in young and old mice

    PubMed Central

    Aguilar, Rhiannon; Harland, Robin A.; Bomar, Bradley A.; Silva, Matthew J.

    2014-01-01

    Murine lumbar and coccygeal (tail) regions of spines are commonly used to study cellular signaling of age-related disc diseases, but the tissue-level changes of aging intervertebral discs and vertebrae of each spinal region remain unclear. Furthermore, the impact of aging lumbar and coccygeal discs on Wnt/β-catenin signaling, which is putatively involved in the catabolism of intervertebral discs, is also unclear. We compared disc/vertebrae morphology and mechanics and biochemical composition of intervertebral discs from lumbar and coccygeal regions between young (4–5 mo) and old (20–22 mo) female C57BL/6 mice. Center intervertebral disc height from both regions was greater in old discs than young discs. Compared with young, old lumbar discs had a lower early viscous coefficient (a measure of stiffness) by 40%, while conversely old coccygeal discs were stiffer by 53%. Biochemically, old mice had double the collagen content in lumbar and coccygeal discs of young discs, greater glycosaminoglycan in lumbar discs by 37%, but less glycosaminoglycan in coccygeal discs by 32%. Next, we compared Wnt activity of lumbar and coccygeal discs of 4- to 5-mo and 12- to 14-mo TOPGAL mice. Despite the disc-specific changes, aging decreased Wnt signaling in the nucleus pulposus from both spinal regions by ≥64%. Compared with young, trabecular bone volume/tissue volume and ultimate force were less in old lumbar vertebrae, but greater in old coccygeal vertebrae. Thus intervertebral discs and vertebrae age in a spinal region-dependent manner, but these differential age-related changes may be uncoupled from Wnt signaling. Overall, lumbar and coccygeal regions are not interchangeable in modeling human aging. PMID:24790018

  6. Comparative role of disc degeneration and ligament failure on functional mechanics of the lumbar spine.

    PubMed

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

    2016-07-01

    Understanding spinal kinematics is essential for distinguishing between pathological conditions of spine disorders, which ultimately lead to low back pain. It is 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 were modelled. Intersegmental range of motion (ROM) and bending stiffness were 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

  7. A Computational Fluid Mechanical Study on the Effects of Opening and Closing of the Mitral Orifice on a Transmitral Flow Velocity Profile and an Early Diastolic Intraventricular Flow

    NASA Astrophysics Data System (ADS)

    Nakamura, Masanori; Wada, Shigeo; Mikami, Taisei; Kitabatake, Akira; Karino, Takeshi

    A computational fluid dynamics study of intraventricular flow during early diastole is carried out to examine the effect of a change in the size of the mitral orifice due to opening and closing of the mitral valve on the flow evolution in the left ventricle during early diastole. It is found that a velocity profile of a transmitral flow with maximum velocity locating at the center of the mitral orifice is generated by gradual opening of the mitral orifice, and it remains even after the mitral orifice has fully opened. This transmitral flow causes the development of a vortex ring extending from the anterior to the posterior side of the left ventricle. The vortex ring keeps the main inflow to stream linearly toward the ventricular apex. Such a flow pattern produces an elongated shape of an aliasing area in a color M-mode Doppler echocardiogram obtained clinically. It is, therefore, considered that although opening and closing of the mitral orifice occur with a short period, they play an important role in characterizing intraventricular flow during early diastole.

  8. Dysfunction of mechanical mitral prosthesis at 33rd week of pregnancy: ECMO support as a complex strategy for the mother and the fetus.

    PubMed

    Di Lorenzo, Gaspare; Martucci, Gennaro; Sciacca, Sergio; Longo, Rosalia; Pilato, Michele; Arcadipane, Antonio

    2016-10-01

    Pregnant women with mechanical prosthetic heart valves have an increased risk of thrombosis and valve malfunctioning. Surgery carries a high risk of mortality for the mother and the fetus. A strategy for effective anticoagulation is crucial for these patients because both oral anticoagulants and heparin are associated with high risks for the mother and the fetus. The treatment of a pregnant woman with thrombosis and valve malfunction is a challenge, even for multidisciplinary teams, as cardiac surgery carries considerable risks. We present a woman at her 33rd week of pregnancy affected by congestive cardiac decompensation due to mechanical mitral prosthesis dysfunction. Given the expanded indication for ECMO and the recent evidence of the procedure's increased safety, even in the peri-partum period, we centered the treatment on VA-ECMO initiation before a Cesarean section (C-section) to guarantee support during surgery and avoid excessive anticoagulation or hypoperfusion to the fetus and as a bridge to cardiac surgery two days later. The strategy resulted in a good outcome with no complications for the mother and the fetus and a reasonable length of stay. PMID:27056763

  9. Mitral Transcatheter Technologies

    PubMed Central

    Maisano, Francesco; Buzzatti, Nicola; Taramasso, Maurizio; Alfieri, Ottavio

    2013-01-01

    Mitral valve regurgitation (MR) is often diagnosed in patients with heart failure and is associated with worsening of symptoms and reduced survival. While surgery remains the gold standard treatment in low-risk patients with degenerative MR, in high-risk patients and in those with functional MR, transcatheter procedures are emerging as an alternative therapeutic option. MitraClip® is the device with which the largest clinical experience has been gained to date, as it offers sustained clinical benefit in selected patients. Further to MitraClip implantation, several additional approaches are developing, to better match with the extreme variability of mitral valve disease. Not only repair is evolving, initial steps towards percutaneous mitral valve implantation have already been undertaken, and initial clinical experience has just started. PMID:23908865

  10. 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. PMID:26961572

  11. A compliant-mechanism approach to achieving specific quality of motion in a lumbar total disc replacement

    PubMed Central

    Halverson, Peter A.; Bowden, Anton E.; Howell, Larry L.

    2012-01-01

    Background The current generation of total disc replacements achieves excellent short- and medium-term results by focusing on restoring the quantity of motion. Recent studies indicate that additional concerns (helical axes of motion, segmental torque-rotation behavior) may have important implications in the health of adjacent segments as well as the health of the surrounding tissue of the operative level. The objective of this article is to outline the development, validation, and biomechanical performance of a novel, compliant-mechanism total disc replacement that addresses these concerns by including them as essential design criteria. Methods Compliant-mechanism design techniques were used to design a total disc replacement capable of replicating the moment-rotation response and the location and path of the helical axis of motion. A prototype was evaluated with the use of bench-top testing and single-level cadaveric experiments in flexion-extension, lateral bending, and axial torsion. Results Bench-top testing confirmed that the moment-rotation response of the disc replacement matched the intended design behavior. Cadaveric testing confirmed that the moment-rotation and displacement response of the implanted segment mimicked those of the healthy spinal segment. Conclusions Incorporation of segmental quality of motion into the foundational stages of the design process resulted in a total disc replacement design that provides torque-rotation and helical axis–of–motion characteristics to the adjacent segments and the operative-level facets that are similar to those observed in healthy spinal segments. PMID:25694875

  12. Evaluation of Quantitative Magnetic Resonance Imaging, Biochemical and Mechanical Properties of Trypsin-Treated Intervertebral Discs Under Physiological Compression Loading

    PubMed Central

    Mwale, Fackson; Demers, Caroline N.; Michalek, Arthur J.; Beaudoin, Gilles; Goswami, Tapas; Beckman, Lorne; Iatridis, James C.; Antoniou, John

    2014-01-01

    Purpose To investigate the influence of targeted trypsin digestion and 16 hours compression loading on MR parameters and the mechanical and biochemical properties of bovine disc segments. Materials and Methods Twenty-two 3-disc bovine coccygeal segments underwent compression loading for 16 hours after the nucleus pulposus (NP) of each disc was injected with a solution of trypsin or buffer. The properties of the NP and annulus fibrosus (AF) tissues of each disc were analyzed by quantitative MRI, biochemical tests, and confined compression tests. Results Loading had a significant effect on the MR properties (T1, T2, T1ρ, MTR, ADC) of both the NP and AF tissues. Loading had a greater effect on the MR parameters and biochemical composition of the NP than trypsin. In contrast, trypsin had a larger effect on the mechanical properties. Our data also indicated that localized trypsin injection predominantly affected the NP. T1ρ was sensitive to loading and correlated with the water content of the NP and AF but not with their proteoglycan content. Conclusion Our studies indicate that physiological loading is an important parameter to consider and that T1ρ contributes new information in efforts to develop quantitative MRI as a noninvasive diagnostic tool to detect changes in early disc degeneration. PMID:18219615

  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. How Is Mitral Valve Prolapse Diagnosed?

    MedlinePlus

    ... page from the NHLBI on Twitter. How Is Mitral Valve Prolapse Diagnosed? Mitral valve prolapse (MVP) most often is detected during a ... a clicking sound as they shut. If the mitral valve is leaking blood back into the left atrium, ...

  15. 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.

  16. Catheter Ablation Related Mitral Valve Injury: The Importance of Early Recognition and Rescue Mitral Valve Repair

    PubMed Central

    DeSimone, Christopher V.; Hu, Tiffany; Ebrille, Elisa; Syed, Faisal F.; Vaidya, Vaibhav R.; Cha, Yong-Mei; Valverde, Arturo M.; Friedman, Paul A.; Suri, Rakesh M.; Asirvatham, Samuel J.

    2015-01-01

    Introduction An increasing number of catheter ablations involve the mitral annular region and valve apparatus, increasing the risk of catheter interaction with the mitral valve (MV) complex. We review our experience with catheter ablation-related MV injury resulting in severe mitral regurgitation (MR) to delineate mechanisms of injury and outcomes. Methods We searched the Mayo Clinic mitral valve surgical database over a 19-year period (1993–2012) and the electrophysiologic procedures database over a 23-year period (1990–2013) and identified 9 patients with catheter ablation related MV injury requiring clinical intervention. Results Indications for ablation included atrial fibrillation (AF) [n=4], ventricular tachycardia (VT) [n =3], and left-sided accessory pathways [n=2]. In all 4 AF patients, a circular mapping catheter entrapped in the MV apparatus was responsible for severe mitral regurgitation. In all 3 VT patients, radiofrequency energy delivery led to direct injury to the MV apparatus. In the 2 patients with accessory pathways, both mechanisms were involved (1 per patient). Six patients required surgical intervention (5 MV repair, 1 catheter removal). One patient developed severe functional MR upon successful endovascular catheter disentanglement that improved spontaneously. Two VT patients with persistent severe post-ablation MR were managed non-surgically, one of whom died 3 months post-procedure. Conclusion Circular mapping catheter entrapment and ablation at the mitral annulus are the most common etiologies of MV injury during catheter ablation. Close surveillance of the MV is needed during such procedures and early surgical repair is important for successful salvage if significant injury occurs. PMID:24758402

  17. 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

  18. DISC1 signaling in cocaine addiction: Towards molecular mechanisms of co-morbidity.

    PubMed

    Gancarz, Amy; Jouroukhin, Yan; Saito, Atsushi; Shevelkin, Alexey; Mueller, Lauren E; Kamiya, Atsushi; Dietz, David M; Pletnikov, Mikhail V

    2016-04-01

    Substance abuse and other psychiatric diseases may share molecular pathology. In order to test this hypothesis, we examined the role of Disrupted In Schizophrenia 1 (DISC1), a psychiatric risk factor, in cocaine self-administration (SA). Cocaine SA significantly increased expression of DISC1 in the nucleus accumbens (NAc); while knockdown of DISC1 in NAc significantly increased cocaine SA and decreased phosphorylation of GSK-3β at Ser9 compared to scrambled shRNA. Our study provides the first mechanistic evidence of a critical role of DISC1 in drug-induced behavioral neuroadaptations and sheds more light at the shared molecular pathology of drug abuse and other major psychiatric disorders. PMID:26385055

  19. Mitral valve replacement in systemic lupus erythematosus associated Libman-Sacks endocarditis.

    PubMed

    Akhlaq, Anam; Ali, Taimur A; Fatimi, Saulat H

    2016-04-01

    Libman-Sacks endocarditis, first discovered in 1924, is a cardiac manifestation of systemic lupus erythematosus (SLE). Valvular involvement has been associated with SLE and antiphospholipid syndrome (APS). Mitral valve, especially its posterior leaflet, is most commonly involved. We report a case of a 34 year old woman with antiphospholipid antibody syndrome and SLE, who presented with mitral valve regurgitation. The patient underwent a prosthetic mitral valve replacement, with no followup complications. We suggest mechanical valve replacement employment in the management of mitral regurgitation in Libman-Sacks endocarditis, in view of the recent medical literature and our own case report. PMID:27053904

  20. Three-Dimensional Numerical Investigations of the Failure Mechanism of a Rock Disc with a Central or Eccentric Hole

    NASA Astrophysics Data System (ADS)

    Wang, S. Y.; Sloan, S. W.; Tang, C. A.

    2014-11-01

    The diametrical compression of a circular disc (Brazilian test) or cylinder with a small eccentric hole is a simple but important test to determine the tensile strength of rocks. This paper studies the failure mechanism of circular disc with an eccentric hole by a 3D numerical model (RFPA3D). A feature of the code RFPA3D is that it can numerically simulate the evolution of cracks in three-dimensional space, as well as the heterogeneity of the rock mass. First, numerically simulated Brazilian tests are compared with experimental results. Special attention is given to the effect of the thickness to radius ratio on the failure modes and the peak stress of specimens. The effects of the compressive strength to tensile strength ratio ( C/T), the loading arc angle (2 α), and the homogeneity index ( m) are also studied in the numerical simulations. Secondly, the failure process of a rock disc with a central hole is studied. The effects of the ratio of the internal hole radius ( r) to the radius of the rock disc ( R) on the failure mode and the peak stress are investigated. Thirdly, the influence of the vertical and horizontal eccentricity of an internal hole on the initiation and propagation of cracks inside a specimen are simulated. The effect of the radius of the eccentric hole and the homogeneity index ( m) are also investigated.

  1. Lumbar extension exercises in conjunction with mechanical traction for the management of a patient with a lumbar herniated disc.

    PubMed

    Gagne, Allison R; Hasson, Scott M

    2010-05-01

    Low back pain resulting from lumbar disc herniation is a common reason for referral for physical therapy. There is no evidence to support the management of lumbar disc herniation and derangement using mechanical traction combined with lumbar extension exercises. Therefore, the purpose of this case report was to describe and discuss the use of mechanical traction in conjunction with lumbar extension exercises for a patient with a lumbar herniated disc. The patient was a 49-year-old male referred to physical therapy with a medical diagnosis of a lumbar herniated disc at L5-S1 with compression of the L5 nerve root confirmed by MRI. The patient's chief complaint was pain over the left lumbosacral and central lumbar region with radiating pain into the left buttock accompanied by numbness and tingling in the left lower leg and foot. The patient was seen for a total of 14 visits. The first 5 days (2 weeks) of therapy consisted of lumbar extension exercises. For the following nine visits (over a 3-week period), mechanical traction was added as an adjunct to the extension exercises. Outcome measures included the Oswestry Disability Questionnaire, Back Pain Function Scale (BPFS), and the Numeric Pain Rating Scale (NPRS). Results from initial evaluation to discharge (Oswestry: 36% to 0%; BPFS: 33/60 to 57/60; NPRS: 7/10 to 0/10) demonstrated that the patient no longer experienced low back pain and improved in terms of functional status and pain-related disability. The patient no longer complained of numbness and tingling in the left lower extremity and the goals for the patient had been attained. The data from this case report suggests lumbar extension exercises in conjunction with mechanical traction facilitated the patient's improvement in pain and return to prior level of function. PMID:20397860

  2. Initiation and progression of mechanical damage in the intervertebral disc under cyclic loading using continuum damage mechanics methodology: A finite element study

    PubMed Central

    Qasim, Muhammad; Natarajan, Raghu N.; An, Howard S.; Andersson, Gunnar B.J.

    2013-01-01

    It is difficult to study the breakdown of disc tissue over several years of exposure to bending and lifting by experimental methods. There is also no finite element model that elucidates the failure mechanism due to repetitive loading of the lumbar motion segment. The aim of this study was to refine an already validated poro-elastic finite element model of lumbar motion segment to investigate the initiation and progression of mechanical damage in the disc under simple and complex cyclic loading conditions. Continuum damage mechanics methodology was incorporated into the finite element model to track the damage accumulation in the annulus in response to the repetitive loading. The analyses showed that the damage initiated at the posterior inner annulus adjacent to the endplates and propagated outwards towards its periphery under all loading conditions simulated. The damage accumulated preferentially in the posterior region of the annulus. The analyses also showed that the disc failure is unlikely to happen with repetitive bending in the absence of compressive load. Compressive cyclic loading with low peak load magnitude also did not create the failure of the disc. The finite element model results were consistent with the experimental and clinical observations in terms of the region of failure, magnitude of applied loads and the number of load cycles survived. PMID:22682891

  3. Initiation and progression of mechanical damage in the intervertebral disc under cyclic loading using continuum damage mechanics methodology: A finite element study.

    PubMed

    Qasim, Muhammad; Natarajan, Raghu N; An, Howard S; Andersson, Gunnar B J

    2012-07-26

    It is difficult to study the breakdown of disc tissue over several years of exposure to bending and lifting by experimental methods. There is also no finite element model that elucidates the failure mechanism due to repetitive loading of the lumbar motion segment. The aim of this study was to refine an already validated poro-elastic finite element model of lumbar motion segment to investigate the initiation and progression of mechanical damage in the disc under simple and complex cyclic loading conditions. Continuum damage mechanics methodology was incorporated into the finite element model to track the damage accumulation in the annulus in response to the repetitive loading. The analyses showed that the damage initiated at the posterior inner annulus adjacent to the endplates and propagated outwards towards its periphery under all loading conditions simulated. The damage accumulated preferentially in the posterior region of the annulus. The analyses also showed that the disc failure is unlikely to happen with repetitive bending in the absence of compressive load. Compressive cyclic loading with low peak load magnitude also did not create the failure of the disc. The finite element model results were consistent with the experimental and clinical observations in terms of the region of failure, magnitude of applied loads and the number of load cycles survived. PMID:22682891

  4. Integrated accretion disc angular momentum removal and astrophysical jet acceleration mechanism

    NASA Astrophysics Data System (ADS)

    Bellan, P. M.

    2016-06-01

    Ions and neutrals in the weakly ionized plasma of an accretion disc are tightly bound because of the high ion-neutral collision frequency. A cluster of a statistically large number of ions and neutrals behaves as a fluid element having the charge of the ions and the mass of the neutrals. This fluid element is effectively a metaparticle having such an extremely small charge-to-mass ratio that its cyclotron frequency can be of the order of the Kepler angular frequency. In this case, metaparticles with a critical charge-to-mass ratio can have zero canonical angular momentum. Zero canonical angular momentum metaparticles experience no centrifugal force and spiral inwards towards the central body. Accumulation of these inward spiralling metaparticles near the central body produces radially and axially outward electric fields. The axially outward electric field drives an out-of-plane poloidal electric current along arched poloidal flux surfaces in the highly ionized volume outside the disc. This out-of-plane current and its associated magnetic field produce forces that drive bidirectional astrophysical jets flowing normal to and away from the disc. The poloidal electric current circuit removes angular momentum from the accreting mass and deposits this removed angular momentum at near infinite radius in the disc plane. The disc region is an electric power source (E\\cdot J <0) while the jet region is an electric power sink (E\\cdot J>0).

  5. 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.

  6. [Mitral valve replacement for congenital parachute mitral valve].

    PubMed

    Sasahashi, N; Ando, F; Okamoto, F; Yamanaka, K; Hanada, T; Makino, S

    1995-07-01

    A one-year-old boy was admitted with refractory congestive biventricular heart failure for medical treatment. On echocardiogram and cardiac catheterization revealed severe mitral stenosis from parachute deformity with pulmonary hypertension. During the operation, a single round orifice of 7 mm in diameter was detected in the mitral valve and adhered chordae were attached to a large single papillary muscle which was located at the posteromedial portion of the left ventricle. An isolated muscle band which was not attached to the mitral valve was observed at the anterolateral wall of the left ventricle. The mitral valve was replaced with 16 mm Carbo-Medicus prosthesis. Postoperative catheterization revealed residual pulmonary hypertension which was responsive to Imidarine infusion. He was discharged from the hospital without any sequelae, and has been on regimen including anticoaglant and vasodilator. PMID:7561327

  7. Innovations in minimally invasive mitral valve pair.

    PubMed

    Sündermann, Simon H; Seeburger, Joerg; Scherman, Jacques; Mohr, Friedrich Wilhelm; Falk, Volkmar

    2012-12-01

    Mitral valve (MV) insufficiency is the second most common heart valve disease represented in cardiac surgery. The gold standard therapy is surgical repair of the valve. Today, most centers prefer a minimally invasive approach through a right-sided mini-thoracotomy. Despite the small access, there is still the need to use cardiopulmonary bypass (CPB), and the operation has to be performed on the arrested heart. New devices have been developed to optimize the results of surgical repair by implementing mechanisms for post-implantation adjustment on the beating heart or the avoidance of CPB. Early attempts with adjustable mitral annuloplasty rings go back to the early 1990s. Only a few devices are available on the market. Recently, a mitral valve adjustable annuloplasty ring was CE-marked and is under further clinical investigation. In addition, a sutureless annuloplasty band to be implanted on the beating heart is under preclinical and initial clinical investigation for transatrial and transfemoral transcatheter implantation. Furthermore, new neochord systems are being developed, which allow for functional length adjustment on the beating heart after implantation. Some devices were developed for percutaneous MV repair implanted into the coronary sinus to reshape the posterior MV annulus. Other percutaneous devices are directly fixed to the posterior annulus to alter its shape. Several disadvantages have been observed preventing a broad clinical use of some of these devices. There is a continuous effort to develop innovative techniques to optimize MV repair and to decrease invasiveness. PMID:23315719

  8. Crystal Structure of MC159 Reveals Molecular Mechanism of DISC Assembly and FLIP Inhibition

    PubMed Central

    Yang, Jin Kuk; Wang, Liwei; Zheng, Lixin; Wan, Fengyi; Ahmed, Misonara; Lenardo, Michael J.

    2010-01-01

    Summary The death inducing signaling complex (DISC) comprising Fas, FADD and caspase-8/10 is assembled via homotypic associations between death domains (DDs) of Fas and FADD and between death effector domains (DEDs) of FADD and caspase-8/10. Caspase-8/10 and FLICE/caspase-8 inhibitory proteins (FLIPs) that inhibit caspase activation at the DISC level contain tandem DEDs. Here we report the crystal structure of a viral FLIP, MC159, at 1.2Å resolution. It reveals a non-canonical fold of DED1, a dumbbell-shaped structure with rigidly associated DEDs and a new mode of interaction in the DD superfamily. While the conserved hydrophobic patch of DED1 interacts with DED2, the corresponding region of DED2 mediates caspase-8 recruitment and contributes to DISC assembly. In contrast, MC159 cooperatively assembles with Fas and FADD via an extensive surface that encompasses the conserved charge triad. This interaction apparently competes with FADD self-association and disrupts higher order oligomerization required for caspase activation in the DISC. PMID:16364918

  9. 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

  10. Measurement of mitral valve area in mitral stenosis by Doppler ultrasound.

    PubMed

    Robson, D J; Rodman, M; Flaxman, J C; Mayhew, F A

    1985-09-01

    The mitral valve area in mitral stenosis was determined from Doppler velocity recordings and by cross-sectional echocardiography. There was good agreement (r = 0.93) between the two methods in 18 adult patients with mitral stenosis. The results confirm that the non-invasive continuous wave Doppler ultrasound technique is of diagnostic value in the assessment of mitral stenosis. PMID:4076215

  11. Region-dependent aggrecan degradation patterns in the rat intervertebral disc are affected by mechanical loading in vivo

    PubMed Central

    Iatridis, James C.; Godburn, Karolyn; Wuertz, Karin; Alini, Mauro; Roughley, Peter J.

    2010-01-01

    Structured Abstract Study Design Immunoblotting study to evaluate aggrecan degradation patterns in rat intervertebral discs(IVDs) subjected to mechanical overload. Objective To evaluate the effects of in vivo dynamic compression overloading on aggrecan degradation products associated with matrix metalloproteinase(MMP) and aggrecanase activity in different regions of the IVD. Summary of Background Data Aggrecan cleavage at the MMP and aggrecanase sites are important events in human IVD aging, with distinct cleavage patterns in the annulus and nucleus regions. No such information is available on regional variations in rat IVDs, nor on how such cleavage is affected by mechanical loading. Methods Sprague-Dawley rats were instrumented with an Ilizarov-type device and subjected to dynamic compression (1 MPa and 1 Hz for 8 hours per day for 8 weeks). Control, sham, and overloaded IVDs were separated by disc region and analyzed for aggrecan degradation products using immunoblotting techniques with antibodies specific for the aggrecanase and MMP cleavage sites in the interglobular domain of aggrecan. Results Control IVDs exhibited strong regional variation in aggrecan degradation patterns with minimal degradation products being present in the nucleus pulposus(NP), degradation products associated with aggrecanase cleavage predominating in the inner annulus fibrosus(AF), and degradation products associated with MMP cleavage predominating in the outer annulus fibrosus. Dynamic compression overloading increased the amount of aggrecan degradation products associated with MMP cleavage particularly in the AF but also in the NP. Degradation profiles of sham IVDs were similar to control. Conclusions Aggrecan G1 regions resulting from proteolysis were found to have a strong regionally-specific pattern in the rat IVD, which was altered under excessive loading. The shift from aggrecanase to MMP-induced degradation products with dynamic compression overloading suggests that protein

  12. Update on percutaneous mitral commissurotomy.

    PubMed

    Nunes, Maria Carmo P; Nascimento, Bruno Ramos; Lodi-Junqueira, Lucas; Tan, Timothy C; Athayde, Guilherme Rafael Sant'Anna; Hung, Judy

    2016-04-01

    Percutaneous mitral commissurotomy (PMC) is the first-line therapy for managing rheumatic mitral stenosis. Over the past two decades, the indications of the procedure have expanded to include patients with unfavourable valve anatomy as a consequence of epidemiological changes in patient population. The procedure is increasingly being performed in patients with increased age, more deformed valves and associated comorbidities. Echocardiography plays a crucial role in patient selection and to guide a more efficient procedure. The main echocardiographic predictors of immediate results after PMC are mitral valve area, subvalvular thickening and valve calcification, especially at the commissural level. However, procedural success rate is not only dependent on valve anatomy, but a number of other factors including patient characteristics, interventional management strategies and operator expertise. Severe mitral regurgitation continues to be the most common immediate procedural complication with unchanged incidence rates over time. The long-term outcome after PMC is mainly determined by the immediate procedural results. Postprocedural parameters associated with late adverse events include mitral valve area, mitral regurgitation severity, mean gradient and pulmonary artery pressure. Mitral restenosis is an important predictor of event-free survival rates after successful PMC, and repeat procedure can be considered in cases with commissural refusion. PMC can be performed in special situations, which include high-risk patients, during pregnancy and in the presence of left atrial thrombus, especially in centres with specialised expertise. Therefore, procedural decision-making should take into account the several determinant factors of PMC outcomes. This paper provides an overview and update of PMC techniques, complications, immediate and long-term results over time, and assessment of suitability for the procedure. PMID:26743926

  13. 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

  14. 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. PMID:26301497

  15. 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

  16. Emergency mitral valve replacement for traumatic mitral insufficiency following balloon mitral valvotomy: an early haemodynamic study.

    PubMed

    Tempe, D K; Mehta, N; Mohan, J C; Tandon, M S; Nigam, M

    1998-07-01

    Acute severe mitral insufficiency may occur during percutaneous transvenous balloon mitarl valvotomy. Urgent surgical intervention in the form of mitral valve repair or replacement may be necessary in these patients. The haemodynamic measurements at various stages in these patients were obtained and compared with those of patients undergoing elective mitral valve replacement for chronic mitral regurgitation. Between September 1995 and December 1947, urgent mitral valve replacement was performed in 14 patients out of a total of 1688 patients who underwent balloon mitral valvotomy. Haemodynamic measurements could be obtained in 7 of these patients and they constituted group I. Eight other patients undergoing elective mitral valve replacement during the same period for chronic mitral regurgitation constituted group II. Standard haemodynamic measurements were obtained at the following stages: (1) Baseline- 20-30 min after endotracheal intubation; (2) stage 1- 20-30 min after termination of the cardiopulmonary bypass: (3) stage 2- four hours after the patient was transferred to ICU and (4) stage 3-30 min after extubation. All the patients were suffering from severe pulmonary hypertension. However, the indices of pulmonary artery hypertension such as mean pulmonary artery pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance as well as right ventricular systolic and end-diastolic pressures did not decrease after surgery in group I. In contrast, in group II, there was significant decrease in mean pulmonary artery pressure (p<0.05), pulmonary capillary wedge pressure (p<0.05), right ventricular systolic (p<0.001) and end-diastolic pressures (p<0.05) at stage 1. These changes persisted throughout the study period. Pulmonary vascular resistance showed a decreasing trend, but attained statistical significance at stage 1 only. Two patients died; one of intractable cardiac failure and another from septicaemia and multiple organ failure in group I, but

  17. 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

  18. Current challenges in interventional mitral valve treatment

    PubMed Central

    Candreva, Alessandro; Pozzoli, Alberto; Guidotti, Andrea; Gaemperli, Oliver; Nietlispach, Fabian; Barthelmes, Jens; Emmert, Maximilian Y.; Weber, Alberto; Benussi, Stefano; Alfieri, Ottavio; Maisano, Francesco

    2015-01-01

    Transcatheter mitral valve therapies have emerged as an alternative option in high surgical risk or inoperable patients with severe and symptomatic mitral regurgitation (MR). As multiple technologies and different approaches will become available in the field of mitral valve interventions, different challenges are emerging, both patient- (clinical challenges) and procedure-related (technical challenges). This review will briefly explore the current open challenges in the evolving fields of interventional mitral valve treatment. PMID:26543599

  19. Modified Surgical Intervention for Extensive Mitral Valve Endocarditis and Posterior Mitral Annular Calcification

    PubMed Central

    Kim, Gwan Sic; Beom, Min Sun; Kim, Sung Ryong; Kim, Na Rae; Jang, Ji Wook; Jang, Mi Hee; Ryu, Sang Wan

    2016-01-01

    The concomitant presence of posterior mitral annular calcification and infectious mitral valve lesions poses a technical challenge with considerable perioperative risk when using previously proposed techniques for mitral valve surgery. Herein, we report a case of the use of a modified surgical technique to successfully treat a patient with mitral infective endocarditis complicated by a subendocardial abscess and extensive posterior mitral annular calcification. PMID:26889447

  20. Mitral Annuloplasty Using a Cardiac Resynchronization Device

    PubMed Central

    Manzoor Ali, Andrabi Syed; Iqbal, Khurshid; Trambu, Nisar Ahmed

    2010-01-01

    Percutaneous Transvenous Mitral Annuloplasty for mitral regurgitation is in early stages of development and involves a complex intervention which can not be done in patients with left ventricular leads. Since functional mitral regurgitation is common in low ejection fraction states, we propose a device which can serve for annuloplasty in addition to cardiac resynchronization therapy and simplifying the intervention. PMID:20680109

  1. Mechanistic insights into transient severe mitral regurgitation.

    PubMed

    Liang, Jackson J; Syed, Faisal F; Killu, Ammar M; Boilson, Barry A; Nishimura, Rick A; Pislaru, Sorin V

    2015-09-01

    Acute mitral regurgitation (AMR), a known complication of acute coronary syndromes, is usually associated with posterior papillary muscle dysfunction/rupture. In severe cases, management of AMR requires surgical intervention. Reversible severe AMR in patients in the absence of left ventricular systolic dysfunction and coronary artery stenosis may result from processes which cause transient subendocardial ischemia, such as intermittent episodes of hypotension or coronary artery vasospasm. We present two cases of reversible transient AMR due to subendocardial and/or endocardial ischemia, both of which offer insight into the mechanism of transient severe AMR. PMID:26982531

  2. 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

  3. 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. PMID:26267883

  4. [Early bioprosthetic mitral valve thrombosis].

    PubMed

    Tkaczyszyn, Michał; Olbrycht, Tomasz; Kustrzycka Kratochwil, Dorota; Sokolski, Mateusz; Sukiennik Kujawa, Małgorzata; Skiba, Jacek; Gemel, Marek; Banasiak, Waldemar; Jankowska, Ewa A; Ponikowski, Piotr

    2012-01-01

    We present a case of a 70 year-old woman operated due to severe mitral regurgitation. Early after surgery transthoracic echocardiography revealed the decreased effective orifice area of the implanted bioprosthetic valve and the stenotic features of transvalvular flow. Transesophageal echocardiography (TEE) disclosed a thrombotic cause of heterograft dysfunction. Due to the clinical deterioration and the unclear cause of prosthesis stenosis, the patient was reoperated. Intra-operatively bioprosthetic mitral valve thrombosis was confirmed. Precipitating factors of this rare complication including cardiac device related infective endocarditis (CDRIE) and the diagnostic applicability of TEE in this clinical scenario are discussed. PMID:22427084

  5. A Review of Mitral Isthmus Ablation

    PubMed Central

    Wong, Kelvin CK; Betts, Timothy R

    2012-01-01

    Mitral isthmus ablation forms part of the electrophysiologist’s armoury in the catheter ablation treatment of atrial fibrillation. It is well recognised however, that mitral isthmus ablation is technically challenging and incomplete ablation may be pro-arrhythmic, leading some to question its role. This article first reviews the evidence for the use of adjunctive mitral isthmus ablation and its association with the development of macroreentrant perimitral flutter. It then describes the practical techniques of mitral isthmus ablation, with particular emphasis on the assessment of bi-directional mitral isthmus block. The anatomy of the mitral isthmus is also discussed in order to understand the possible obstacles to successful ablation. Finally, novel techniques which may facilitate mitral isthmus ablation are reviewed. PMID:22912536

  6. Rare Case of Unileaflet Mitral Valve

    PubMed Central

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

    2016-01-01

    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. PMID:27358711

  7. Percutaneous transvenous mitral commissurotomy in juvenile mitral stenosis

    PubMed Central

    Malla, Rabi; Rajbhandari, Rajib; Shakya, Urmila; Sharma, Poonam; Shrestha, Nagma; KC, Bishal; Limbu, Deepak; KC, Man Bahadur

    2016-01-01

    Background Percutaneous transvenous mitral commissurotomy (PTMC) is a valid alternative to surgical therapy in selected patients with mitral stenosis. Juvenile mitral stenosis (JMS) varies uniquely from adult rheumatic heart disease (RHD). We aimed to evaluate the efficacy of PTMC in JMS patients. Methods It was a single centre, retrospective study conducted between July 2013 to June 2015 in Shahid Gangalal National Heart Centre, Kathmandu, Nepal. Medical records of all consecutive patients aged less than 21 years who underwent PTMC were included. Mitral valve area (MVA), left atrial pressure and mitral regurgitation (MR) were compared pre and post procedure. Results During the study period 131 JMS patients underwent PTMC. Seventy (53.4%) were female and 61 (46.6%) were male. Among the 131 patients, 40 (30.5%) patients were below the age of 15 years. Patient age ranged between 9 to 20 years with the mean of 16.3±2.9 years. Electrocardiography (ECG) findings were normal sinus rhythm in 115 (87.7%) patients and atrial fibrillation in 16 (12.3%) patients. Left atrial size ranged from 2.9 to 6.1 cm with the mean of 4.5±0.6 cm. The mean MVA increased from 0.8±0.1 cm2 to 1.6±0.2 following PTMC. Mean left atrial pressure decreased from their pre-PTMC state of 27.5±8.6 to 14.1±5.8 mmHg. Successful results were observed in 115 (87.7%) patients. Suboptimal MVA <1.5 cm2 in 11 (8.4%) patients and post-procedure MR of more than moderate MR in 5 (3.8%) patients was the reason for unsuccessful PTMC. Conclusions PTMC in JMS is safe and effective. PMID:26885488

  8. 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.

  9. 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)

  10. Enlargement of mitral valve ring in a young woman with severe prosthesis-patient mismatch.

    PubMed

    Attisani, Matteo; Pellegrini, Augusto; Sorrentino, Paolo; Rinaldi, Mauro

    2014-04-01

    Mechanical prosthesis is the first choice for valve replacement at the mitral position in children. Replacement of the original prosthesis because of prosthesis-patient mismatch (PPM) is almost inevitable when prostheses are implanted in small children. The impact of PPM on long-term mortality becomes significant when the effective orifice area (EOA) is severely reduced. In these cases prosthesis replacement can be technically difficult, and it often requires extended enlargement of the mitral valve annulus ring. We report a case of a woman who underwent a mitral valve replacement with a 19-mm St. Jude mechanical prosthetic valve at the age of 3 years. At the age of 33 years, the patient underwent a successful minimally invasive mitral annulus ring enlargement and implantation of a 23-mm St. Jude mechanical prosthetic valve via a right minithoracotomy. PMID:24808442

  11. 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. PMID:12931115

  12. 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.

  13. Simulated-Physiological Loading Conditions Preserve Biological and Mechanical Properties of Caprine Lumbar Intervertebral Discs in Ex Vivo Culture

    PubMed Central

    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

  14. Biaxial Creep Resistance and Structural Remodeling of the Aortic and Mitral Valves in Pregnancy.

    PubMed

    Pierlot, Caitlin M; Moeller, Andrew D; Lee, J Michael; Wells, Sarah M

    2015-08-01

    Pregnancy produces rapid, dramatic volume-overload changes to the maternal circulation. This paper examines pregnancy-induced structural-mechanical changes in bovine aortic and mitral heart valve leaflets. Valve leaflets were harvested from non-pregnant heifers and pregnant cows. Dimensions, biaxial extensibility and creep resistance were assessed and related to changes in the collagen network: histological leaflet and anatomic layer thicknesses plus collagen crimp, and biochemical collagen content. Collagen stability and crosslinking were assessed thermomechanically. Pregnancy altered both aortic and mitral valve leaflets. Both valves demonstrated biphasic changes in leaflet stretch, decreasing in early pregnancy and recovering by late pregnancy. Creep in leaflets from both valves was minimal and decreased even further with pregnancy in the mitral valve. There were valve-specific changes in preconditioning areal extension with pregnancy: increasing in the aortic valve and decreasing in the mitral valve. Leaflet area increased dramatically (84% aortic, 56% mitral), with thickening mainly in the fibrosa, accompanied by increases in collagen content (8% aortic, 16% mitral): together suggesting synthesis of new collagen. Collagen crimp was almost completely lost in pregnancy, with the denaturation temperature decreased by approximately 2 °C. Mature and total crosslinking increased, curiously without a significant increase in immature crosslinking. Mature aortic and mitral heart valve leaflets in the maternal cardiovascular system remodel substantially and similarly-despite their different embryological origins. PMID:25564325

  15. 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. PMID:27087174

  16. Supravalvar Mitral Ring: a Case Report

    PubMed Central

    Baharestani, Bahador; Sadat Afjehi, Reza; Givtaj, Nader; Sharifi, Mehrzad

    2012-01-01

    Supravalvar mitral ring is a rare congenital heart defect of surgical importance. The condition is characterized by an abnormal ridge of the connective tissue on the atrial side of the mitral valve. It often substantially obstructs the mitral valve inflow. We herein introduce a case of a supravalvar mitral ring in a 17-year-old male, who was admitted to our hospital with cardiac syncope. He had undergone a cardiac operation for ventricular septal defect (VSD) closure and mitral valve repair 15 years before. Transthoracic echocardiography, transesophageal echocardiography, and finally cardiac catheterization revealed a neglected supravalvular mitral ring. The ring was resected in a second operation, and the patient was discharged from the hospital symptom free. PMID:23074643

  17. Cardiac resynchronisation therapy after percutaneous mitral annuloplasty

    PubMed Central

    Swampillai, Janice

    2016-01-01

    Percutaneous approaches to reduce mitral regurgitation in ischemic cardiomyopathy have stirred interest recently. Patients with ischemic cardiomyopathy and functional mitral regurgitation often meet criteria for cardiac resynchronisation therapy to improve left ventricular function as well as mitral regurgitation, and alleviate symptoms. This case shows that implantation of a pacing lead in the coronary sinus to restore synchronous left and right ventricular contraction is feasible, despite the presence of a remodeling device in the coronary sinus. PMID:27182527

  18. Transbilayer coupling mechanism for the formation of lipid asymmetry in biological membranes. Application to the photoreceptor disc membrane.

    PubMed Central

    Hubbell, W L

    1990-01-01

    An equilibrium transmembrane asymmetry in charged lipids is shown to arise as a result of oriented, bipolar proteins in the membrane. The basic interaction giving rise to the asymmetry is between a lipid molecule and a transbilayer potential generated by the asymmetric charge distribution in the protein. Thus, a protein can generate a lipid asymmetry without a direct binding interaction between lipid and protein. The generation of an asymmetry in charged lipid by this mechanism can also lead to a concomitant asymmetry in neutral lipids if deviations from ideality in the lipid mixture are taken into account. It is shown that regular solution theory applied to the lipid phase predicts an asymmetry in all components of a ternary mixture as long as one component is electrostatically oriented according to the mechanism mentioned above. The resulting asymmetry is not strongly salt dependent. The mechanism quantitatively accounts for the experimentally determined phospholipid asymmetry in the rod outer segment disc membrane of the vertebrate photoreceptor. PMID:2297564

  19. Mitral Stenosis Presenting as Asthma.

    PubMed

    Li, Shenjing; Jbeli, Aiham; Stys, Maria; Stys, Adam

    2016-02-01

    Although wheezing is one of the most common symptoms and physical findings in asthma, other causes of wheezing should be kept in mind: vocal cord dysfunction, postnasal drip syndrome, chronic obstructive pulmonary disease, bronchiectasis, and non-pulmonary diseases, like heart failure and pulmonary edema. Here, we present a case of severe mitral stenosis with pulmonary edema treated for resistant asthma. If asthma is difficult to control, other etiologies of wheezing, including cardiac disease, should be taken into consideration during diagnosis. PMID:26999914

  20. Asymptomatic large left-atrial ball thrombus. Secondary to mitral stenosis.

    PubMed Central

    Vitale, M; Agnino, A; Serena, D; Schena, S; Piscitelli, D; Fiore, T; de Luca Tupputi Schinosa, L

    1997-01-01

    We describe the very unusual case of a patient with a large, free-floating left-atrial thrombus secondary to severe mitral stenosis, in whom the peculiar symptoms and complications of a ball thrombus were absent. The patient's only symptom before the episode reported here was mild dyspnea, which was attributed to mitral stenosis. She experienced neither embolism nor syncope. While even her clinical signs did not indicate a left-atrial ball thrombus, both echocardiography and angiography showed a free-floating thrombus. Because of the risk of stroke and acute obstruction of the mitral valve, emergency surgery was performed upon diagnosis of the ball thrombus. The surgery, which consisted of removing the thrombus and replacing the mitral valve with a mechanical prosthesis, was uneventful. A computed tomographic brain scan prior to discharge did not detect any cerebral infarction. Images PMID:9456496

  1. Wear of the Charité® lumbar intervertebral disc replacement investigated using an electro-mechanical spine simulator

    PubMed Central

    Moghadas, Parshia; Shepherd, Duncan ET; Hukins, David WL

    2015-01-01

    The Charité® lumbar intervertebral disc replacement was subjected to wear testing in an electro-mechanical spine simulator. Sinusoidally varying compression (0.6–2 kN, frequency 2 Hz), rotation (±2°, frequency 1 Hz), flexion–extension (6° to −3°, frequency 1 Hz) and lateral bending (±2°, frequency 1 Hz) were applied out of phase to specimens immersed in diluted calf serum at 37 °C. The mass of the ultra-high-molecular weight polyethylene component of the device was measured at intervals of 0.5, 1, 2, 3, 4 and 5 million cycles; its volume was also measured by micro-computed tomography. Total mass and volume losses were 60.3 ± 4.6 mg (mean ± standard deviation) and 64.6 ± 6.0 mm3. Corresponding wear rates were 12.0 ± 1.4 mg per million cycles and 12.8 ± 1.2 mm3 per million cycles; the rate of loss of volume corresponds to a mass loss of 11.9 ± 1.1 mg per million cycles, that is, the two sets of measurements of wear agree closely. Wear rates also agree closely with measurements made in another laboratory using the same protocol but using a conventional mechanical spine simulator. PMID:25834002

  2. Severe mitral regurgitation due to anterior mitral leaflet perforation after surgical treatment of discrete subaortic stenosis.

    PubMed

    Ozyuksel, Arda; Yildirim, Ozgur; Onsel, Ibrahim; Bilal, Mehmet Salih

    2014-01-01

    Congenital subvalvular aortic stenosis may be associated with anomalies of the mitral valve. In this case, we present a patient with severe mitral valve regurgitation due to a perforation in the anterior mitral leaflet detected 4 months after an operation for relief of subaortic stenosis. A 10-year-old male patient who was operated for subvalvular aortic stenosis in another clinic was admitted to our hospital, and transthoracic echocardiography revealed severe mitral valve regurgitation due to a defect that was demonstrated at the anterior valve leaflet. The perforated area at the mitral valve zone A1 was repaired with a PTFE patch. The patient was successfully operated for the mitral valve perforation and the postoperative course was uneventful. In our case, the perforation in the anterior mitral leaflet implies a possible implementation of inappropriate surgical technique which necessitated a second surgical intervention after the initial operation. PMID:24859561

  3. Severe mitral regurgitation due to anterior mitral leaflet perforation after surgical treatment of discrete subaortic stenosis

    PubMed Central

    Ozyuksel, Arda; Yildirim, Ozgur; Onsel, Ibrahim; Bilal, Mehmet Salih

    2014-01-01

    Congenital subvalvular aortic stenosis may be associated with anomalies of the mitral valve. In this case, we present a patient with severe mitral valve regurgitation due to a perforation in the anterior mitral leaflet detected 4 months after an operation for relief of subaortic stenosis. A 10-year-old male patient who was operated for subvalvular aortic stenosis in another clinic was admitted to our hospital, and transthoracic echocardiography revealed severe mitral valve regurgitation due to a defect that was demonstrated at the anterior valve leaflet. The perforated area at the mitral valve zone A1 was repaired with a PTFE patch. The patient was successfully operated for the mitral valve perforation and the postoperative course was uneventful. In our case, the perforation in the anterior mitral leaflet implies a possible implementation of inappropriate surgical technique which necessitated a second surgical intervention after the initial operation. PMID:24859561

  4. Hemolysis and infective endocarditis in a mitral prosthetic valve.

    PubMed

    Koç, Fatih; Bekar, Lütfi; Kadı, Hasan; Ceyhan, Köksal

    2010-09-01

    Traumatic intravascular hemolysis after heart valve replacement can be a serious problem. It is commonly associated with either structural deterioration or paravalvular leaks. A 63-year-old woman with a six-year history of surgery for mitral stenosis presented with complaints of weakness and dyspnea. She received treatment at other centers three times in the past six months for dyspnea and anemia requiring transfusion of red blood cells. Transthoracic echocardiography showed a normally functioning mitral mechanic prosthesis. Laboratory findings were abnormal for hemoglobin, hematocrit, white blood cell count, C-reactive protein, serum haptoglobin, and lactate dehydrogenase. Peripheral blood smear showed marked schistocytes, indicative of mechanical erythrocyte destruction. Transesophageal echocardiography demonstrated severe paravalvular leak and a large (9x13 mm) vegetation adhering to the prosthetic valve, protruding into the left atrium. Enterococcus faecalis was isolated from blood cultures. Surgery was planned because of large vegetation, repeated hemolysis, and severe paravalvular regurgitation, but the patient refused surgical treatment. PMID:21200125

  5. Parachute deformity of the mitral valve

    PubMed Central

    Bett, J. H. N.; Stovin, P. G. I.

    1969-01-01

    A case of parachute deformity of the mitral valve, a rare congenital form of mitral stenosis characterized by insertion of the chordae tendineae into a single posterior papillary muscle, is described in an 11-year-old girl. The eleven other cases in the English literature are reviewed. Images PMID:5348334

  6. Anatomical challenges for transcatheter mitral valve intervention.

    PubMed

    DE Backer, Ole; Luk, Ngai H; Søndergaard, Lars

    2016-06-01

    Following the success of transcatheter aortic and pulmonary valve implantation, there is a large interest in transcatheter mitral valve interventions to treat severe mitral regurgitation (MR). With the exception for the MitraClipTM (Abbott, Abbott Park, IL, USA) edge-to-edge leaflet plication system, most of these transcatheter mitral valve interventions are still in their early clinical or preclinical development phase. Challenges arising from the complex anatomy of the mitral valve and the interplay of the mitral apparatus with the left ventricle (LV) have contributed to a more difficult development process and mixed clinical results with these novel technologies. This review aims to discuss the several anatomical aspects and challenges related to transcatheter mitral valve intervention - the relevant anatomy will be reviewed in relation to specific requirements for device design and procedural aspects of transcatheter mitral valve interventions. To date, experience with these novel therapeutic modalities are still limited and resolution of many challenges are pending. Future studies have to evaluate for whom the transcatheter approach is a feasible and preferred treatment and which patients will benefit from either transcatheter mitral valve repair or replacement. Nevertheless, technological developments are anticipated to drive the transcatheter approach forward into a clinically feasible alternative to surgery for selected patients with severe MR. PMID:27028333

  7. 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. PMID:26004435

  8. DISC0VR, a unique tool to study the mechanisms that generate ozone mini-holes

    NASA Astrophysics Data System (ADS)

    Teitelbaum, H.

    2011-12-01

    An ozone mini-hole is a region of strongly depleted column total ozone amount, that can persist for several days. They are characterized by a rapid and small-scale decrease of columnar ozone and an equally rapid recovery after a few days. "Mini ozone holes" are frequently observed at northern hemisphere mid-latitudes in winter. They evolve rapidly and according to some authors, may originate because of northeast motions of air patches with low total ozone content. However, several other studies attribute the formation of ozone mini-holes to the uplift of air masses that decrease the ozone columnar content by simply decreasing the pressure thickness of the ozone layer, without changing the mixing ratio. According to these studies, the latter mechanism explains the main reduction of ozone that occurs between the tropopause and the ozone maximum during an ozone mini-hole event. Since ozone mini-holes cannot be the result of ozone chemical destruction, they should be the result of meteorological processes. In many cases the mini-holes move, the direction and speed of movement is of great importance for the study of the mechanism that causes the phenomenon. DISCOVR, because of its spatial resolution, continuous time coverage and its ability to detect ozone, can describe the irregularities of ozone and its displacement. Complemented by a method of tracing air mass trajectories (FLEXTRA) the DSCOVR observations will allow us to determine the mechanisms of ozone mini-holes formation.

  9. 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

  10. Balloon mitral valvotomy in youngest documented rheumatic mitral stenosis patient.

    PubMed

    Sarkar, Achyut; Patil, Shailesh; Ahmed, Imran

    2015-11-01

    Juvenile rheumatic mitral stenosis (MS) is common in the Indian subcontinent. Early recognition and management is essential. Rarely rheumatic MS may occur in <5 years of age, wherein rapid hemodynamic progression and cardiac morbidity and mortality occurs. Severe/symptomatic MS in preschool age requires urgent and meticulous decision making. Condition of valve and wishes of parents may complicate management decisions. Percutaneous transmitral commissurotomy (PTMC) may, therefore, become the only life-saving intervention in these cases unless contraindicated, although the procedure entails considerable technical issues in this age group. Herein, we report a successful balloon mitral valvotomy in a 4-year-old child with severe rheumatic MS (documented since 2 years 6 months of age) presenting with repeated pulmonary edema. To the best of our knowledge, this child is the youngest documented case of established rheumatic heart disease and also one of the youngest PTMC procedure performed. This report supports the clinical usefulness of PTMC in childhood MS; however, pertinent technical issues are raised, which needs a proper consensus. PMID:26012486

  11. Anterior mitral annulus caseoma: as benign as posterior counterparts?

    PubMed

    Mazzucco, Alessandro; Abbasciano, Riccardo; Onorati, Francesco; Brognoli, Gabriele; Fanti, Diego; Gottin, Leonardo; Faggian, Giuseppe

    2016-01-01

    Mitral annular caseoma is a common incidental finding involving the posterior annulus. It has an innocent nature, with the exception of its endocarditic degeneration and/or a stenotic functional effect when exophytic. We report an exceptionally rare isolated anterior mitral annular caseoma involving also the anterior mitral leaflet and affecting its physiologic systolic movement, thus resulting in a restricting anterior leaflet motion responsible for mitral insufficiency. The case was successfully treated by complex mitral valve repair. PMID:26522681

  12. Quantum size effect on ZnO nanoparticle-based discs synthesized by mechanical milling

    NASA Astrophysics Data System (ADS)

    Sendi, Rabab Khalid; Mahmud, Shahrom

    2012-08-01

    Zinc oxide (ZnO) nanoparticles ranging ∼7-15 nm in size were successfully synthesized by the ball-milling technique. Mechanical milling was found very functional in producing ZnO nanoparticles with the possibility of obtaining large quantities. The milled nanoparticles were compared with commercial ZnO nanopowder. High-resolution scanning electron microscopy and atomic force microscopy analyses revealed a reduction in the lattice space and grain size with increased milling time, as well as severe lattice deformations in some of the nanoparticles. The milling process also had a significant effect on the grain crystallinity as illustrated by decreased lattice strain based on the X-ray diffraction lattice constant and full-wave at half-maximum data. The photoluminescence (PL) spectra of the ZnO powder showed a UV emission band at 380 nm with a visible PL emission in the green band peaking at 535 nm. The relative intensities of these peaks drastically changed with increased milling time due to the size quantization effect and surface defects (oxygen vacancies and zinc/oxygen interstitials) in the ZnO nanopowder. The Raman spectra of the ZnO powder indicated eight sets of optical phonon modes at the Γ point of the Brillouin zone, which red shifted and broadened with increased milling time. As the milling proceeded, clearly reduced grain size, homogenization, and other properties were observed.

  13. 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. PMID:27449468

  14. Transcatheter direct mitral valve annuloplasty with the Cardioband system for the treatment of functional mitral regurgitation.

    PubMed

    Taramasso, Maurizio; Inderbitzin, Devdas T; Guidotti, Andrea; Nietlispach, Fabian; Gaemperli, Oliver; Zuber, Michel; Maisano, Francesco

    2016-01-01

    Direct mitral valve annuloplasty is a transcatheter mitral valve repair approach that mimics the conventional surgical approach to treat functional mitral regurgitation. The Cardioband system (Valtech Cardio, Inc., Or-Yehuda, Israel) is delivered by a trans-septal approach and the implant is performed on the atrial side of the mitral annulus, under live echo and fluoroscopic guidance using multiple anchor elements. The Cardioband system obtained CE mark approval in October 2015, and initial clinical experiences are promising with regard to feasibility, safety and efficacy. PMID:27247326

  15. Transcatheter mitral valve repair for functional mitral regurgitation: coronary sinus approach.

    PubMed

    Piazza, Nicolo; Bonan, Raoul

    2007-12-01

    Mitral regurgitation has become recognized as an important health problem. More specifically, functional mitral regurgitation is associated with worse outcomes in heart failure, postmyocardial infarction, and perioperative coronary artery bypass surgery patients. Many patients with severe mitral regurgitation are denied or refused mitral valve surgery. A less invasive procedure with possibly fewer potential complications may thus be attractive for patients with severe mitral regurgitation. Devices used for coronary sinus (CS) mitral annuloplasty are directed toward patients with functional mitral regurgitation. Because of its easy accessibility and close relationship to the posterior mitral annulus (MA), alterations of the CS geometry with percutaneous devices may translate to displacement of the posterior annulus and correct mitral leaflet coaptation. This review will focus on the contemporary CS annuloplasty devices: (1) Edwards MONARC system; (2) Cardiac Dimensions CARILLON; and (3) Viacor Shape Changing Rods system. In addition, important information obtained from recent imaging studies describing the relationship between the CS, MA, and coronary arteries will be reviewed. PMID:18042055

  16. 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. PMID:24905180

  17. [Percutaneous mitral commissurotomy associated to sinus venosus atrial septal defect and partially anomalous pulmonary venous connection: a case report].

    PubMed

    Fradi El Faleh, I; Ezzar, M T; Zaroui, A; Boussaada, R; Mechmèche, R

    2014-04-01

    Lutembacher's syndrome refers to the rare combination of congenital atrial septal defect and acquired mitral stenosis. It is rarely associated to partial anomalous pulmonary venous connection. This condition is treated surgically by mitral commissurotomy or mitral valve operation with concomitant closure of the atrial septal defect with correction of the abnormal pulmonary venous connection. Percutaneous mitral commissurotomy before surgery can be a therapeutic alternative when mitral valve stenosis is severe and valve anatomy is favourable. The authors bring back the case of a 24 years old man having mitral stenosis in sinus rhythm associated to sinus venosus septal defect and partial anomalous pulmonary venous connection. The diagnosis was made for the age of 17 years old on the occasion of dyspnea. He benefited in February 2003 of rescue percutaneous mitral commissurotomy because of pulmonary oedema. Mitral valve area increased from 0.7 cm(2) to 1.6 cm(2). The patient was clinically approved, so that he refused surgery and was lost sight. Seven years later (August 2010) he was taken back for a second rescue percutaneous mitral commissurotomy because of a very severe mitral stenosis (mitral valve area was 0.8cm(2)), in pulmonary oedema with echocardiographic evaluated pulmonary hypertension at 68mmHg. The trans-septal complicated of a false road from the right atrium, towards the pericardic cavity. The patient was operated as the matter of urgency, and benefited from a mitral valve replacement by mechanical prosthesis, of closure of sinus venosus septal defect by PTFE patch and correction of abnormal pulmonary venous connection. Operating suites were simple, and the postoperative echocardiography concludes to a good prosthesis profile, the absence of residual shunt and a decrease of pulmonary artery blood pressure from 68 to 40mmHg. In conclusion, percutaneous mitral commissurotomy may be a waiting procedure for surgery of this disease or emergency treatment of

  18. Effect of ventricle motion on the dynamic behaviour of chorded mitral valves

    NASA Astrophysics Data System (ADS)

    Watton, P. N.; Luo, X. Y.; Yin, M.; Bernacca, G. M.; Wheatley, D. J.

    2008-01-01

    An Immersed Boundary (IB) model is employed to investigate the dynamic behaviour of a novel chorded mitral prosthesis, which is in the early stages of its development, under physiological flow conditions. In vivo magnetic resonance images (MRIs) of the left ventricle are analysed to determine the relative motion of the mitral annulus and the papillary muscle regions of the ventricle. The dynamic boundary conditions are incorporated into IB simulations to test the valve in a more realistic dynamic geometric environment. The IB model has successfully identified the effect of the dynamic boundary conditions on the mechanical behaviour of the valve and revealed the strengths and weaknesses of the current mitral design. The mechanical performance of the prosthesis is compared with recent studies of native porcine valves; differences in mechanical behaviour are observed. Potential improvements for the design of the prosthesis are proposed.

  19. How Is Mitral Valve Prolapse Treated?

    MedlinePlus

    ... Living With Clinical Trials Links Related Topics Arrhythmia Endocarditis Heart Valve Disease How the Heart Works Marfan ... underlying mitral valve problem, if necessary Preventing infective endocarditis , arrhythmias , and other complications Relieving symptoms Medicines Medicines ...

  20. Mitral annular disjunction in myxomatous mitral valve disease: a relevant abnormality recognizable by transthoracic echocardiography

    PubMed Central

    2010-01-01

    Background Mitral annular disjunction (MAD) consists of an altered spatial relation between the left atrial wall, the attachment of the mitral leaflets, and the top of the left ventricular (LV) free wall, manifested as a wide separation between the atrial wall-mitral valve junction and the top of the LV free wall. Originally described in association with myxomatous mitral valve disease, this abnormality was recently revisited by a surgical group that pointed its relevance for mitral valve reparability. The aims of this study were to investigate the echocardiographic prevalence of mitral annular disjunction in patients with myxomatous mitral valve disease, and to characterize the clinical profile and echocardiographic features of these patients. Methods We evaluated 38 patients with myxomatous mitral valve disease (mean age 57 ± 15 years; 18 females) and used standard transthoracic echocardiography for measuring the MAD. Mitral annular function, assessed by end-diastolic and end-systolic annular diameters, was compared between patients with and without MAD. We compared the incidence of arrhythmias in a subset of 21 patients studied with 24-hour Holter monitoring. Results MAD was present in 21 (55%) patients (mean length: 7.4 ± 8.7 mm), and was more common in women (61% vs 38% in men; p = 0.047). MAD patients more frequently presented chest pain (43% vs 12% in the absence of MAD; p = 0.07). Mitral annular function was significantly impaired in patients with MAD in whom the mitral annular diameter was paradoxically larger in systole than in diastole: the diastolic-to-systolic mitral annular diameter difference was -4,6 ± 4,7 mm in these patients vs 3,4 ± 1,1 mm in those without MAD (p < 0.001). The severity of MAD significantly correlated with the occurrence of non-sustained ventricular tachycardia (NSVT) on Holter monitoring: MAD›8.5 mm was a strong predictor for (NSVT), (area under ROC curve = 0.74 (95% CI, 0.5-0.9); sensitivity 67%, specificity 83%). There

  1. 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

  2. Quantification of mitral apparatus dynamics in functional and ischemic mitral regurgitation using real-time 3-dimensional echocardiography.

    PubMed

    Veronesi, Federico; Corsi, Cristiana; Sugeng, Lissa; Caiani, Enrico G; Weinert, Lynn; Mor-Avi, Victor; Cerutti, Sergio; Lamberti, Claudio; Lang, Roberto M

    2008-04-01

    Mitral regurgitation (MR) in dilated cardiomyopathy (DCM-MR) and MR in ischemic cardiomyopathy (ISC-MR) usually occurs as a result of mitral annulus (MA) dilatation and papillary muscle displacement secondary to global left ventricle remodelling. We propose a method to determine MA area and motion throughout the cardiac cycle and to define papillary muscle position in 3-dimensional space using real-time 3-dimensional echocardiography. Real-time 3-dimensional echocardiography was performed in 24 healthy individuals, and in 30 patients with DCM-MR (n = 15) or ISC-MR (n = 15). Significant intergroup differences were noted in MA surface area (control: 6.4 +/- 1.7 cm(2); DCM-MR: 11.1 +/- 2.6 cm(2); ISC-MR: 9.0 +/- 2.0 cm(2)) and in peak MA motion (control: 8.7 +/- 3.0 mm; DCM-MR: 3.4 +/- 1.7 mm; ISC-MR: 4.9 +/- 1.5 mm). In patients with DCM-MR, papillary muscle symmetry was preserved, whereas in patients with ISC-MR, papillary tethering lengths were unequal as a result of wall-motion abnormalities. Our methodology for dynamic volumetric measurements of the mitral apparatus allows better understanding of MR mechanisms. PMID:17681731

  3. 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. PMID:26045488

  4. Glucosamine loaded injectable silk-in-silk integrated system modulate mechanical properties in bovine ex-vivo degenerated intervertebral disc model.

    PubMed

    Murab, Sumit; Samal, Juhi; Shrivastava, Akshay; Ray, Alok Ranjan; Pandit, Abhay; Ghosh, Sourabh

    2015-07-01

    Injectable hydrogels offer a tremendous potential for treatment of degenerated intervertebral disc due to their ability to withstand complex loading, conforming precisely to the defect spaces and eliminating the need for invasive surgical procedures. We have developed an injectable hydrogel platform of N-acetyl-glucosamine (GlcNAc) loaded silk hollow spheres embedded in silk hydrogel for in situ therapeutic release and enhanced mechanical strength. The assembled silk hydrogel provided adequate structural support to the ex vivo degenerated disc model in a cyclic compression test at par with the native tissue. Spatiotemporal release of GlcNAc in a controlled manner from the silk hollow microspheres trigger enhanced proteoglycan production from ADSCs embedded in the composite system. Role of MAPK and SMAD pathways in increasing proteoglycan production have been explored by immunohistological analysis as a result of the action of GlcNAc on the cells, elucidating the potential of injectable silk microsphere-in-silk hydrogel for the regeneration of degenerated disc tissue. PMID:25934453

  5. Competing Mechanisms of Gamma and Beta Oscillations in the Olfactory Bulb Based on Multimodal Inhibition of Mitral Cells Over a Respiratory Cycle123

    PubMed Central

    Courtiol, Emmanuelle; Buonviso, Nathalie

    2015-01-01

    Gamma (∼40-90 Hz) and beta (∼15-40 Hz) oscillations and their associated neuronal assemblies are key features of neuronal sensory processing. However, the mechanisms involved in either their interaction and/or the switch between these different regimes in most sensory systems remain misunderstood. Based on in vivo recordings and biophysical modeling of the mammalian olfactory bulb (OB), we propose a general scheme where OB internal dynamics can sustain two distinct dynamic states, each dominated by either a gamma or a beta regime. The occurrence of each regime depends on the excitability level of granule cells, the main OB interneurons. Using this model framework, we demonstrate how the balance between sensory and centrifugal input can control the switch between the two oscillatory dynamic states. In parallel, we experimentally observed that sensory and centrifugal inputs to the rat OB could both be modulated by the respiration of the animal (2-12 Hz) and each one phase shifted with the other. Implementing this phase shift in our model resulted in the appearance of the alternation between gamma and beta rhythms within a single respiratory cycle, as in our experimental results under urethane anesthesia. Our theoretical framework can also account for the oscillatory frequency response, depending on the odor intensity, the odor valence, and the animal sniffing strategy observed under various conditions including animal freely-moving. Importantly, the results of the present model can form a basis to understand how fast rhythms could be controlled by the slower sensory and centrifugal modulations linked to the respiration. Visual Abstract: See Abstract PMID:26665163

  6. End-diastolic amplitude of mitral valve echogram in mitral stenosis.

    PubMed Central

    Toutouzas, P; Velimezis, A; Karayannis, E; Avgoustakis, D

    1977-01-01

    By using simultaneous recordings of the mitral valve echogram and apex cardiogram, the mitral echogram amplitude was measured at the onset of left ventricular isovolumic contraction (MAIC). Twenty normal subjects and 68 patients with a reduced diastolic closure rate in the mitral valve echogram were studied. Of these patients, 53 had mitral stenosis, 6 aortic valvar stenosis, and 9 hypertrophic obstructive cardiomyopathy. In the normal subjects the MAIC ranged between 2 and 4 mm, average 2-7 mm, in the patients with aortic valvar stenosis or hypertrophic obstructive cardiomyopathy between 2 and 4 mm, average 2-9 mm, and in the patients with mitral stenosis between 6 and 17 mm, average 11-3 mm. The DE/MAIC ratio, where DE represents the opening amplitude of the mitral valve in early diastole, was between 3-3 and 6-5, average 5-1, in normal subjects; in the patients with aortic stenosis or hypertrophic obstructive cardiomyopathy the DE/MAIC ratio was between 2-7 and 6-5, average 4-2, and in the patients with mitral stenosis between 0-7 and 1-5, average 1-1. An excellent correlation was found between the DE/MAIC ratio and mitral valve area in the patients with mitral stenosis (r = 0-84, P less than 0-01) while the correlation between the diastolic closure rate and valve area was less satisfactory (4 = 0-62, P less than 0-01). These findings suggest that in cases with a reduced diastolic closure rate for reasons other than mitral stenosis, error can be avoided by using the DE/MAIC ratio. PMID:556669

  7. Janus discs.

    PubMed

    Walther, Andreas; André, Xavier; Drechsler, Markus; Abetz, Volker; Müller, Axel H E

    2007-05-16

    We describe the synthesis and the solution properties of sheet- and disclike Janus particles, containing an inner crosslinked polybutadiene (PB) layer and two different outer sides of polystyrene (PS) and poly(tert-butyl methacrylate) (PtBMA). The structures formed upon adsorption of the flat Janus particles onto solid substrates as well as in THF solution are investigated. The Janus discs are obtained in a template-assisted synthetic pathway followed by sonication. Selectively crosslinking the lamellar PB domains in a well-ordered lamellar microphase-separated bulk morphology of PS-block-PB-block-PtBMA (SBT) block terpolymers leads to the conservation of the compartmentalization of the two outer blocks. Sonication of the crosslinked block terpolymer templates renders soluble sheet- and disclike Janus particles, the size of which can be tuned from the micrometer range down to the nanometer scale. Small-angle X-ray scattering, transmission electron microscopy, dynamic light scattering, scanning force microscopy, and scanning electron microscopy are used to characterize the template-assisted synthetic process and the solution properties. Cryogenic transmission electron microscopy in THF and TEM of particles, embedded into a photo-crosslinkable silicon oil, indicate a supramolecular aggregation behavior of the Janus discs in concentrated solutions. Pendant drop tensiometry demonstrates that Janus sheets and discs can be used to stabilize liquid-liquid interfaces, rendering these materials interesting for future applications. PMID:17441717

  8. Comparison of Percutaneous Mitral Valve Repair Versus Conservative Treatment in Severe Functional Mitral Regurgitation.

    PubMed

    Giannini, Cristina; Fiorelli, Francesca; De Carlo, Marco; Guarracino, Fabio; Faggioni, Michela; Giordano, Paolo; Spontoni, Paolo; Pieroni, Andrea; Petronio, Anna Sonia

    2016-01-15

    Percutaneous mitral valve repair (PMVR) using the MitraClip System is feasible and entails clinical improvement even in patients with high surgical risk and severe functional mitral regurgitation (MR). The aim of this study was to assess survival rates and clinical outcome of patients with severe, functional MR treated with optimal medical therapy (OMT) compared with those who received MitraClip device. Sixty patients treated with OMT were compared with a propensity-matched cohort of 60 patients who underwent PMVR. Baseline demographics and echocardiographic variables were similar between the 2 groups. The mean age of patients was 75 years, and 67% were men. The median logistic EuroSCORE and EuroSCORE II were 17% and 6%, respectively, because of the presence of several co-morbidities. The mechanism of MR was functional in all cases with an ischemic etiology in 52% of patients. Median left ventricle ejection fraction was 34%. All the patients were symptomatic for dyspnea with 63% and 12% in the New York Heart Association class III and IV, respectively. In PMVR group, the procedure was associated with safety and very low incidence of procedural complications with no occurrence of procedural and inhospital mortality. After a median follow-up of 515 days (248 to 828 days), patients treated with PMVR demonstrated overall survival, survival freedom from cardiac death and survival free of readmission due to cardiac disease curves higher than patients treated conservatively (log-rank test p = 0.007, p = 0.002, and p = 0.04, respectively). In conclusion, PMVR offers a valid option for selected patients with high surgical risk and severe, functional MR and entails better survival outcomes compared with OMT. PMID:26651454

  9. 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

  10. 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

  11. What Are the Signs and Symptoms of Mitral Valve Prolapse?

    MedlinePlus

    ... from the NHLBI on Twitter. What Are the Signs and Symptoms of Mitral Valve Prolapse? Most people ... major mitral valve backflow. When MVP does cause signs and symptoms, they may include: Palpitations (feelings that ...

  12. Surgical treatment of functional ischemic mitral regurgitation.

    PubMed

    Jensen, Henrik

    2015-03-01

    In many ways we are at a crossroad in terms of what constitutes optimal FIMR treatment: is CABG combined with mitral valve ring annuloplasty better than CABG alone in moderate FIMR? Is mitral valve repair really better than replacement? And does adding a valvular repair or subvalvular reverse remodeling procedure shift that balance? In the present thesis I aim to shed further light on these questions by addressing the current status and future perspectives of the surgical treatment of FIMR. CURRENT SURGICAL TREATMENT FOR FIMR. CABG alone: The overall impression from the literature is that patients are left with a high grade of persistent/recurrent FIMR from isolated CABG. CABG is most effective to treat FIMR in patients with viable myocardium (at least five viable segments) and absence of dyssynchrony between papillary muscles (< 60 ms). Mitral valve ring annuloplasty. A vast number of different designs are available to perform mitral valve ring annuloplasty with variations over the theme of complete/partial and rigid/semi-rigid/flexible. Also, the three-dimensional shape of the rigid and semi-rigid rings is the subject of great variation. A rigid or semi-rigid down-sized mitral valve ring annuloplasty is the most advocated treatment in chronic FIMR grade 2+ or higher. Combined CABG and mitral valve ring annuloplasty: CABG combined with mitral valve ring annuloplasty leads to reverse LV remodeling and reduced volumes. Despite this, the recurrence rate after combined CABG and mitral valve ring annuloplasty is 20-30% at 2-4 years follow-up. This is also true for studies strictly using down-sized mitral valve ring annuloplasty by two sizes. A number of preoperative risk factors to develop recurrent FIMR were identified, e.g. LVEDD > 65-70 mm, coaptation depth > 10 mm, anterior leaflet angle > 27-39.5°, posterior leaflet angle > 45° and interpapillary muscle distance > 20 mm. CABG alone vs. combined CABG and mitral valve ring annuloplasty: The current available

  13. 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. PMID:25967681

  14. Surgical Treatment of Moderate Ischemic Mitral Regurgitation

    PubMed Central

    Smith, P.K.; Puskas, J.D.; Ascheim, D.D.; Voisine, P.; Gelijns, A.C.; Moskowitz, A.J.; Hung, J.W.; Parides, M.K.; Ailawadi, G.; Perrault, L.P.; Acker, M.A.; Argenziano, M.; Thourani, V.; Gammie, J.S.; Miller, M.A.; Pagé, P.; Overbey, J.R.; Bagiella, E.; Dagenais, F.; Blackstone, E.H.; Kron, I.L.; J., D.; Rose, E.A.; Moquete, E.G.; Jeffries, N.; Gardner, T.J.; O’Gara, P.T.; Alexander, J.H.; Michler, R.E.

    2015-01-01

    BACKGROUND Ischemic mitral regurgitation is associated with increased mortality and morbidity. For surgical patients with moderate regurgitation, the benefits of adding mitral-valve repair to coronary-artery bypass grafting (CABG) are uncertain. METHODS We randomly assigned 301 patients with moderate ischemic mitral regurgitation to CABG alone or CABG plus mitral-valve repair (combined procedure). The primary end point was the left ventricular end-systolic volume index (LVESVI), a measure of left ventricular remodeling, at 1 year. This end point was assessed with the use of a Wilcoxon rank-sum test in which deaths were categorized as the lowest LVESVI rank. RESULTS At 1 year, the mean LVESVI among surviving patients was 46.1±22.4 ml per square meter of body-surface area in the CABG-alone group and 49.6±31.5 ml per square meter in the combined-procedure group (mean change from baseline, −9.4 and −9.3 ml per square meter, respectively). The rate of death was 6.7% in the combined-procedure group and 7.3% in the CABG-alone group (hazard ratio with mitral-valve repair, 0.90; 95% confidence interval, 0.38 to 2.12; P = 0.81). The rank-based assessment of LVESVI at 1 year (incorporating deaths) showed no significant between-group difference (z score, 0.50; P = 0.61). The addition of mitral-valve repair was associated with a longer bypass time (P<0.001), a longer hospital stay after surgery (P = 0.002), and more neurologic events (P = 0.03). Moderate or severe mitral regurgitation was less common in the combined-procedure group than in the CABG-alone group (11.2% vs. 31.0%, P<0.001). There were no significant between-group differences in major adverse cardiac or cerebrovascular events, deaths, readmissions, functional status, or quality of life at 1 year. CONCLUSIONS In patients with moderate ischemic mitral regurgitation, the addition of mitral-valve repair to CABG did not result in a higher degree of left ventricular reverse remodeling. Mitral-valve repair was

  15. [Giant Left Atrium with Mitral Regurgitation in Williams Syndrome: Report of a Case].

    PubMed

    Suzuki, Ryusuke; Sakaguchi, Takeshi; Uekihara, Kenta; Mouri, Masaharu; Yoshioka, Yuki; Miyamoto, Tomoya; Hirayama, Ryo; Watanabe, Toshiaki; Matsukawa, Mai; Nakajima, Masamichi

    2016-02-01

    A 43-year-old woman with a history of mitral regurgitation and Williams syndrome was admitted for the treatment of congestive heart failure. A computed tomography scan showed a giant left atrium. No other cardiac abnormalities were observed. She received mitral valve replacement with a mechanical valve prosthesis and underwent left atrium volume reduction with a suture technique and modified Maze procedure. After the operation, the cardiac rhythm returned to sinus rhythm and chest radiography showed normal cardiothoracic ratio. Congestive heart failure did not recur. PMID:27075158

  16. Delayed migration of Sapien valve following a transcatheter mitral valve-in-valve implantation.

    PubMed

    Bapat, Vinayak Vinnie Nilkanth; Khaliel, Feras; Ihleberg, Leo

    2014-01-01

    We report two cases of delayed migration of the Sapien XT device after a successful mitral valve-in-valve (VIV) implantation. The procedure was performed through a transapical approach. Echocardiography was used to choose the size of the Sapien XT device. Although the immediate results were satisfactory both the cases presented with severe regurgitation (1 week and 3 months). Investigations revealed atrial migration of the Sapien device in both the cases, which was confirmed at the time of reoperation. We discuss possible mechanisms, which could have resulted in the delayed migration and highlight the difference between VIV procedures in mitral position versus other positions. PMID:23784983

  17. On the Design of an Interactive, Patient-Specific Surgical Simulator for Mitral Valve Repair

    PubMed Central

    Tenenholtz, Neil A.; Hammer, Peter E.; Schneider, Robert J.; Vasilyev, Nikolay V.; Howe, Robert D.

    2011-01-01

    Surgical repair of the mitral valve is a difficult procedure that is often avoided in favor of less effective valve replacement because of the associated technical challenges facing non-expert surgeons. In the interest of increasing the rate of valve repair, an accurate, interactive surgical simulator for mitral valve repair was developed. With a haptic interface, users can interact with a mechanical model during simulation to aid in the development of a surgical plan and then virtually implement the procedure to assess its efficacy. Sub-millimeter accuracy was achieved in a validation study, and the system was successfully used by a cardiac surgeon to repair three virtual pathological valves. PMID:24511427

  18. 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…

  19. Percutaneous balloon mitral valvuloplasty by the Inoue balloon technique: the procedure of choice for treatment of mitral stenosis.

    PubMed

    Cheng, T O; Holmes, D R

    1998-03-01

    The Inoue technique of percutaneous balloon mitral valvuloplasty, introduced in 1984, is a truly startling advance in cardiology in modern times. It is time to reeducate our colleagues that when they hear the opening snap in patients with mitral stenosis, they should automatically open these stenotic mitral valves with an Inoue balloon catheter rather than submit these patients to surgical correction. PMID:9514461

  20. Percutaneous valve repair for mitral regurgitation using the Carillon Mitral Contour System. Description of the method and case report.

    PubMed

    Siminiak, Tomasz; Firek, Ludwik; Jerzykowska, Olga; Kałmucki, Piotr; Wołoszyn, Maciej; Smuszkiewicz, Piotr; Link, Rafał

    2007-03-01

    Mitral regurgitation may result from left ventricular dilatation and cause progression of heart failure. Percutaneous techniques for mitral valve repair are under development. Techniques utilizing a trans-coronary venous approach exploit the anatomical relationship between the mitral annulus and the venous system of the heart. The coronary sinus, great cardiac vein and the origin of the anterior interventricular vein surround the posterior mitral annulus. This enables percutaneous approaches to annuloplasty for mitral regurgitation. Devices can be implanted into the coronary veins that modify the shape and size of the mitral annulus. We present a case of ischaemic mitral regurgitation successfully treated by use of a percutaneous approach, the Carillon Mitral Contour System. Significant reduction of the mitral regurgitation jet was observed. The patient was discharged 4 days after the procedure. During the follow-up visits, the patient showed an improved general condition and increased exercise capacity. Procedural steps are shown in detail and the current status of the coronary sinus based technique is discussed. Percutaneous techniques for mitral valve repair may be an attractive alternative to cardiac surgery in heart failure patients with secondary mitral regurgitation. The Carillon Mitral Contour System is under ongoing clinical evaluation in the AMADEUS trial. PMID:17436155

  1. Piezogenic Pedal Papules with Mitral Valve Prolapse.

    PubMed

    Altin, Cihan; Askin, Ulku; Gezmis, Esin; Muderrisoglu, Haldun

    2016-01-01

    Piezogenic pedal papules (PPP) are herniations of subcutaneous adipose tissue into the dermis. PPP are skin-colored to yellowish papules and nodules on lateral surfaces of feet that typically become apparent when the patient stands flat on his/her feet. Some connective tissue diseases and syndromes have been reported in association with PPP. Mitral valve prolapse (MVP) is a myxomatous degeneration of the mitral valve, characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. MVP may be isolated or part of a heritable connective tissue disorder. PPP, which is generally considered as an isolated lesion, might be also a predictor of some cardiac diseases associated with connective tissue abnormalities such as MVP. A detailed systemic investigation including cardiac examination should be done in patients with PPP. Since in the literature, there are no case reports of association of PPP with MVP, we report these cases. PMID:27057041

  2. Piezogenic Pedal Papules with Mitral Valve Prolapse

    PubMed Central

    Altin, Cihan; Askin, Ulku; Gezmis, Esin; Muderrisoglu, Haldun

    2016-01-01

    Piezogenic pedal papules (PPP) are herniations of subcutaneous adipose tissue into the dermis. PPP are skin-colored to yellowish papules and nodules on lateral surfaces of feet that typically become apparent when the patient stands flat on his/her feet. Some connective tissue diseases and syndromes have been reported in association with PPP. Mitral valve prolapse (MVP) is a myxomatous degeneration of the mitral valve, characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. MVP may be isolated or part of a heritable connective tissue disorder. PPP, which is generally considered as an isolated lesion, might be also a predictor of some cardiac diseases associated with connective tissue abnormalities such as MVP. A detailed systemic investigation including cardiac examination should be done in patients with PPP. Since in the literature, there are no case reports of association of PPP with MVP, we report these cases. PMID:27057041

  3. 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.

  4. Artificial Disc Replacement

    MedlinePlus

    ... treat this condition, alternatives to disc replacement include fusion, nonoperative care or no treatment. Typically, surgery is ... operative treatment for disc pain has been spinal fusion. This is a surgical procedure in which disc ...

  5. 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

  6. A Rare Case of Mitral Valve Prolapse in Endomyocardial Fibrosis.

    PubMed

    Xavier, Joseph; Haranal, Maruti Yamanappa; Reddy, Shashidhar Ranga; Suryaprakash, Sharadaprasad

    2016-09-01

    Mitral valve prolapse in endomyocardial fibrosis (EMF) is an unusual entity. Literature search reveals only 1 report of mitral valve prolapse assosiated with EMF. A 32-year-old woman, of African origin, who presented with features of right heart failure, was diagnosed to have mitral valve prolapse of rheumatic origin with severe mitral regurgitation and severe pulmonary hypertension (PAH). Intraoperative findings lead to the diagnosis of EMF. We report this rare case of mitral valve prolapse in EMF, in a geographical area where rheumatic heart disease is endemic, to showcase how a rare manifestation of EMF can be misdiagnosed as that of rheumatic heart disease. PMID:27549547

  7. 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. PMID:27217424

  8. Palliative Mitral Valve Repair During Infancy for Neonatal Marfan Syndrome.

    PubMed

    Kitahara, Hiroto; Aeba, Ryo; Takaki, Hidenobu; Shimizu, Hideyuki

    2016-05-01

    An infant with neonatal Marfan syndrome (nMFS), a condition that is nearly always lethal during infancy, was referred to our hospital with symptoms of congestive heart failure resulting from severe mitral valve insufficiency. During mitral valve repair, the use of an annuloplasty ring was waived until annular dilatation was achieved after 2 palliative mitral valvuloplasty procedures. After the definitive operation, the patient's mitral valve function remained within normal limits until the last follow-up when the patient was 11 years old. To the best of our knowledge, this patient has the longest recorded survival after mitral valve repair. PMID:27106438

  9. 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

  10. Changes in Mitral Annular Geometry after Aortic Valve Replacement: A Three-Dimensional Transesophageal Echocardiographic Study

    PubMed Central

    Mahmood, Feroze; Warraich, Haider J.; Gorman, Joseph H.; Gorman, Robert C.; Chen, Tzong-Huei; Panzica, Peter; Maslow, Andrew; Khabbaz, Kamal

    2014-01-01

    Background and aim of the study Intraoperative real-time three-dimensional transesophageal echocardiography (RT-3D TEE) was used to examine the geometric changes that occur in the mitral annulus immediately after aortic valve replacement (AVR). Methods A total of 35 patients undergoing elective surgical AVR under cardiopulmonary bypass was enrolled in the study. Intraoperative RT-3D TEE was used prospectively to acquire volumetric echocardiographic datasets immediately before and after AVR. The 3D echocardiographic data were analyzed offline using TomTec® Mitral Valve Assessment software to assess changes in specific mitral annular geometric parameters. Results Datasets were successfully acquired and analyzed for all patients. A significant reduction was noted in the mitral annular area (-16.3%, p <0.001), circumference (-8.9% p <0.001) and the anteroposterior (-6.3%, p = 0.019) and anterolateral-posteromedial (-10.5%, p <0.001) diameters. A greater reduction was noted in the anterior annulus length compared to the posterior annulus length (10.5% versus 62%, p <0.05) after AVR. No significant change was seen in the non-planarity angle, coaptation depth, and closure line length. During the period of data acquisition before and after AVR, no significant change was noted in the central venous pressure or left ventricular end-diastolic diameter. Conclusion The mitral annulus undergoes significant geometric changes immediately after AVR Notably, a 16.3% reduction was observed in the mitral annular area. The anterior annulus underwent a greater reduction in length compared to the posterior annulus, which suggested the existence of a mechanical compression by the prosthetic valve. PMID:23409347

  11. Recommended transoesophageal echocardiographic evaluation of mitral valve regurgitation

    PubMed Central

    Hokken, R.B.; ten Cate, F.J.; van Herwerden, L.A.

    2006-01-01

    Valve replacement in patients with mitral valve regurgitation is indicated when symptoms occur or left ventricular function becomes impaired. Using different surgical techniques, mitral valve reconstruction has lead to earlier interventions with good clinical results. In order to determine the possibility of a mitral valve reconstruction, echocardiographic parameters are necessary. With transoesophageal echocardiography a segmental analysis of the entire mitral valve can be performed; mitral valve motion abnormalities and severity and direction of the regurgitation jet can be judged. From this analysis clues for underlying pathology can be derived as well as the eligibility of a successful mitral valve reconstruction. This article focuses on transoesophageal examination with segmental analysis in patients with mitral valve regurgitation. PMID:25696623

  12. Characterization of biomechanical properties of aged human and ovine mitral valve chordae tendineae.

    PubMed

    Zuo, Keping; Pham, Thuy; Li, Kewei; Martin, Caitlin; He, Zhaoming; Sun, Wei

    2016-09-01

    The mitral valve (MV) is a highly complex cardiac valve consisting of an annulus, anterior and posterior leaflets, chordae tendineae (chords) and two papillary muscles. The chordae tendineae mechanics play a pivotal role in proper MV function: the chords help maintain proper leaflet coaptation and rupture of the chordae tendineae due to disease or aging can lead to mitral valve insufficiency. Therefore, the aim of this study was to characterize the mechanical properties of aged human and ovine mitral chordae tendineae. The human and ovine chordal specimens were categorized by insertion location (i.e., marginal, basal and strut) and leaflet type (i.e., anterior and posterior). The results show that human and ovine chords of differing types vary largely in size but do not have significantly different elastic and failure properties. The excess fibrous tissue layers surrounding the central core of human chords added thickness to the chords but did not contribute to the overall strength of the chords. In general, the thinner marginal chords were stiffer than the thicker basal and strut chords, and the anterior chords were stiffer and weaker than the posterior chords. The human chords of all types were significantly stiffer than the corresponding ovine chords and exhibited much lower failure strains. These findings can be explained by the diminished crimp pattern of collagen fibers of the human mitral chords observed histologically. Moreover, the mechanical testing data was modeled with the nonlinear hyperelastic Ogden strain energy function to facilitate accurate computational modeling of the human MV. PMID:27315372

  13. 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

  14. [Cervical disc herniation].

    PubMed

    Schnake, K J; Hoffmann, C-H; Kandziora, F

    2012-12-01

    The cervical disc herniation is characterized by prolapsed nucleus pulposus material through the annulus into the spinal canal. The local mechanical or chemical irritation of neural structures typically leads to symptoms of radiculopathy, cervicocephalgia or myelopathy. Pronounced sensorimotor deficits or intractable pain constitute surgical treatment. In all other cases conservative treatment is indicated, including pain medication, active and passive physiotherapy, and local injections, respectively. Anterior cervical discectomy and interbody fusion (ACDF) is still the surgical treatment of choice. Predominantly, cages with or without plates are in use to obtain solid fusion. The implantation of a total disc replacement is a viable alternative, if no contraindications exist. Other surgical techniques may be performed in proper selected cases. The overall clinical and radiological results of both surgical and conservative treatment are good. PMID:23296562

  15. 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.

  16. Balloon expandable transcatheter heart valves for native mitral valve disease with severe mitral annular calcification.

    PubMed

    Guerrero, Mayra; Urena, Marina; Pursnani, Amit; Wang, Dee D; Vahanian, Alec; O'Neill, William; Feldman, Ted; Himbert, Dominique

    2016-06-01

    Patients with mitral annular calcification (MAC) have high surgical risk for mitral valve replacement due to associated comorbidities and technical challenges related to calcium burden, precluding surgery in many patients. Transcatheter mitral valve replacement (TMVR) with the compassionate use of balloon expandable aortic transcatheter heart valves has been used in this clinical scenario. The purpose of this review was to summarize the early experience including successes and failures reported. TMVR might evolve into an acceptable alternative for selected patients with severe MAC who are not candidates for conventional mitral valve surgery. However, this field is at a very early stage and the progress will be significantly slower than the development of transcatheter aortic valve replacement due to the complexity of the mitral valve anatomy and its pathology. Optimizing patient selection process by using multimodality imaging tools to accurately measure the mitral valve annulus and evaluate the risk of left ventricular outflow tract obstruction is essential to minimize complications. Strategies for treating and preventing left ventricular outflow tract obstruction are being tested. Similarly, carefully selecting candidates avoiding patients at the end of their disease process, might improve the overall outcomes. PMID:27094423

  17. Disc cell senescence in intervertebral disc degeneration: Causes and molecular pathways

    PubMed Central

    Feng, Chencheng; Liu, Huan; Yang, Minghui; Zhang, Yang; Huang, Bo; Zhou, Yue

    2016-01-01

    ABSTRACT The accumulation of senescent disc cells in degenerative intervertebral disc (IVD) suggests the detrimental roles of cell senescence in the pathogenesis of intervertebral disc degeneration (IDD). Disc cell senescence decreased the number of functional cells in IVD. Moreover, the senescent disc cells were supposed to accelerate the process of IDD via their aberrant paracrine effects by which senescent cells cause the senescence of neighboring cells and enhance the matrix catabolism and inflammation in IVD. Thus, anti-senescence has been proposed as a novel therapeutic target for IDD. However, the development of anti-senescence therapy is based on our understanding of the molecular mechanism of disc cell senescence. In this review, we focused on the molecular mechanism of disc cell senescence, including the causes and various molecular pathways. We found that, during the process of IDD, age-related damages together with degenerative external stimuli activated both p53-p21-Rb and p16-Rb pathways to induce disc cell senescence. Meanwhile, disc cell senescence was regulated by multiple signaling pathways, suggesting the complex regulating network of disc cell senescence. To understand the mechanism of disc cell senescence better contributes to developing the anti-senescence-based therapies for IDD. PMID:27192096

  18. Percutaneous and minimally invasive approaches to mitral valve repair for severe mitral regurgitation-new devices and emerging outcomes

    PubMed Central

    Shamoun, Fadi E.; Craner, Ryan C.; Seggern, Rita Von; Makar, Gerges; Ramakrishna, Harish

    2015-01-01

    Mitral valve disease is common in the United States and around the world, and if left untreated, increases cardiovascular morbidity and mortality. Mitral valve repair is technically more demanding than mitral valve replacement. Mitral valve repair should be considered the first line of treatment for mitral regurgitation in younger patients, mitral valve prolapse, annular dilatation, and with structural damage to the valve. Several minimally invasive percutaneous treatment options for mitral valve repair are available that are not restricted to conventional surgical approaches, and may be better received by patients. A useful classification system of these approaches proposed by Chiam and Ruiz is based on anatomic targets and device action upon the leaflets, annulus, chordae, and left ventricle. Future directions of minimally invasive techniques will include improving the safety profile through patient selection and risk stratification, improvement of current imaging and techniques, and multidisciplinary education. PMID:26440239

  19. 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…

  20. 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

  1. Correlations between quantitative T2 and T1ρ MRI, mechanical properties and biochemical composition in a rabbit lumbar intervertebral disc degeneration model.

    PubMed

    Gullbrand, Sarah E; Ashinsky, Beth G; Martin, John T; Pickup, Stephen; Smith, Lachlan J; Mauck, Robert L; Smith, Harvey E

    2016-08-01

    Improved diagnostic measures for intervertebral disc degeneration are necessary to facilitate early detection and treatment. The aim of this study was to correlate changes in mechanical and biochemical properties with the quantitative MRI parameters T2 and T1ρ in rabbit lumbar discs using an ex vivo chymopapain digestion model. Rabbit lumbar spinal motion segments from animals less than 6 months of age were injected with 100 μl of saline (control) or chymopapain at 3, 15, or 100 U/ml (n = 5 per group). T2 and T1ρ MRI series were obtained at 4.7T. Specimens were mechanically tested in tension-compression and creep. Normalized nucleus pulposus (NP) water and GAG contents were quantified. Stepwise multiple linear regression was performed to determine which parameters contributed significantly to changes in NP T2 and T1ρ. When all groups were included, multiple regression yielded a model with GAG, compressive modulus, and the creep time constants as variables significantly impacting T2 (multiple r(2)  = 0.64, p = 0.006). GAG and neutral zone (NZ) modulus were identified as variables contributing to T1ρ (multiple r(2)  = 0.28, p = 0.08). When specimens with advanced degeneration were excluded from the multiple regression analysis, T2 was significantly predicted by compressive modulus, τ1, and water content (multiple r(2)  = 0.71, p = 0.009), while no variables were significant predictors in the model for T1ρ. These results indicate that quantitative MRI can detect changes in the mechanical and biochemical properties of the degenerated disc. T2 may be more sensitive to early stage degenerative changes than T1ρ, while both quantitative MRI parameters are sensitive to advanced degeneration. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1382-1388, 2016. PMID:27105019

  2. 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

    2016-01-01

    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

  3. 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

  4. Intervertebral disc disease.

    PubMed

    Simpson, S T

    1992-07-01

    This article describes the functional anatomy of intervertebral discs and their relationship to the vertebrae and spinal cord. The pathologic events and clinical complications of intervertebral disc disease are described. A discussion of proper staging of disc disease and appropriate conservative management of degenerative disc disease is included. PMID:1641922

  5. ECHO-PHONOCARDIOGRAPHIC CHARACTERISTICS OF THE NORMALLY FUNCTIONING COOLEY-CUTTER MITRAL VALVE PROSTHESIS

    PubMed Central

    Pechacek, Leonard W.; Zarrabi, Ali; Massumkhani, Ali; Garcia, Efrain; De Castro, Carlos M.; Hall, Robert J.

    1979-01-01

    Echocardiographic and phonocardiographic records of 19 patients with a normally functioning Cooley-Cutter mitral valve were analyzed in order to provide quantitative baseline values for this prosthesis. The average duration between the second heart sound and peak opening of the valve (A2-OC interval) was 83 ± 4 (standard error of the mean) msec. The Q-CC interval (from the electrocardiographic Q wave to closure of the valve) was 71 ± 2 msec. Mean opening and closing velocities of the disc were similar (396 ± 11 mm/sec and 393 ± 12 mm/sec, respectively). Amplitude of disc excursion ranged from 6 to 9 mm, but this measurement was not possible in all patients due to the presence of spurious echoes. Early onset of prosthetic valve closure was a relatively common finding in patients with atrial fibrillation or with various forms of atrioventricular block, and frequently resulted in a variety of phonocardiographic alterations. Except for the A2-OC interval and amplitude of disc excursion, there was no significant correlation between valve size and echo-phonocardiographic measurements. Results of this study are compared with values previously reported for other types of caged disc valves, and the usefulness and limitations of echo-phonocardiographic assessment of prosthetic valve function are briefly discussed. Images PMID:15216292

  6. 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

  7. Effects of pimobendan for mitral valve regurgitation in dogs.

    PubMed

    Kanno, Nobuyuki; Kuse, Hiroshi; Kawasaki, Masaya; Hara, Akashi; Kano, Rui; Sasaki, Yoshihide

    2007-04-01

    Pimobendan has a dual mechanism of action: it increases myocardial contractility by increasing calcium sensitization to troponin C and it promotes vasodilation by inhibiting PDEIII. This study examined the effects of pimobendan on cardiac function, hemodynamics, and neurohormonal factors in dogs with mild mitral regurgitation (MR). The dogs were given 0.25 mg/kg of pimobendan orally every 12 hr for 4 weeks. With pimobendan, the heart rate and stroke volume did not change, but the systolic blood pressure gradually decreased and the degree of mitral valve regurgitation tended to decrease. Renal blood flow was significantly increased and the glomerular filtration rate was slightly increased at 2 and 4 weeks. Furthermore, over the 4-week period, the plasma norepinephrine concentration decreased significantly, the systolic index increased slightly, the left atrial diameter and the left ventricular diameters decreased significantly, and the heart size improved. Given these results, pimobendan appears to be useful for treating MR in dogs. However, further long-term studies of pimobendan involving a larger number of dogs with mild and moderate MR are needed to establish the safety of pimobendan and document improvements in quality of life. PMID:17485924

  8. Broken discs: warp propagation in accretion discs

    NASA Astrophysics Data System (ADS)

    Nixon, Christopher J.; King, Andrew R.

    2012-04-01

    We simulate the viscous evolution of an accretion disc around a spinning black hole. In general, any such disc is misaligned, and warped by the Lense-Thirring effect. Unlike previous studies, we use effective viscosities constrained to be consistent with the internal fluid dynamics of the disc. We find that non-linear fluid effects, which reduce the effective viscosities in warped regions, can promote breaking of the disc into two distinct planes. This occurs when the Shakura & Sunyaev dimensionless viscosity parameter α is ≲0.3 and the initial angle of misalignment between the disc and hole is ≳45°. The break can be a long-lived feature, propagating outwards in the disc on the usual alignment time-scale, after which the disc is fully co-aligned or counter-aligned with the hole. Such a break in the disc may be significant in systems where we know the inclination of the outer accretion disc to the line of sight, such as some X-ray binaries: the inner disc, and so any jets, may be noticeably misaligned with respect to the orbital plane.

  9. Disc-planet interactions in subkeplerian discs

    NASA Astrophysics Data System (ADS)

    Paardekooper, S.-J.

    2009-11-01

    Context: One class of protoplanetary disc models, the X-wind model, predicts strongly subkeplerian orbital gas velocities, a configuration that can be sustained by magnetic tension. Aims: We investigate disc-planet interactions in these subkeplerian discs, focusing on orbital migration for low-mass planets and gap formation for high-mass planets. Methods: We use linear calculations and nonlinear hydrodynamical simulations to measure the torque and look at gap formation. In both cases, the subkeplerian nature of the disc is treated as a fixed external constraint. Results: We show that, depending on the degree to which the disc is subkeplerian, the torque on low-mass planets varies between the usual type I torque and the one-sided outer Lindblad torque, which is also negative but an order of magnitude stronger. In strongly subkeplerian discs, corotation effects can be ignored, making migration fast and inward. Gap formation near the planet's orbit is more difficult in such discs, since there are no resonances close to the planet accommodating angular momentum transport. The location of the gap is shifted inwards with respect to the planet, leaving the planet on the outside of a surface density depression. Conclusions: Depending on the degree to which a protoplanetary disc is subkeplerian, disc-planet interactions can be very different from the usual Keplerian picture, making these discs in general more hazardous for young planets.

  10. Development of Off-pump Mitral Valve Replacement in a Porcine Model

    PubMed Central

    Gillespie, Matthew J.; Aoki, Chikashi; Satoshi, Takebayashi; Shimaoka, Toru; McGarvey, Jeremy R.; Gorman, Robert C.; Gorman, Joseph H.

    2015-01-01

    Purpose We describe our initial experience with on-bypass and off-bypass (off-pump) mitral valve replacement with the modified version of our novel catheter-based sutureless mitral valve (SMV2) technology, which was developed to atraumatically anchor and seal in the mitral position. Description The SMV is a self-expanding device consisting of a custom designed nitinol framework and a pericardial leaflet valve mechanism. For the current studies our original device was modified (SMV2) to reduce the delivery profile and to allow for controlled deployment whilst still maintaining the key principles necessary for atraumatic anchoring and sealing in the MV position. Evaluation Ten Yorkshire pigs underwent successful SMV2 device implantation via a left atriotomy (on-pump N=6; off-pump N=4). Echocardiography and angiography revealed excellent LV systolic function, no significant perivalvular leak, no MV stenosis, no left ventricular (LV) outflow tract obstruction and no aortic valve insufficiency. Necropsy demonstrated that the SMV2 devices were anchored securely. Conclusions This study demonstrates the feasibility and short-term success of off-pump mitral valve replacement using a novel, catheter-based device in a porcine model. PMID:25841820

  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. PMID:26577230

  12. 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. PMID:26926991

  13. Tearing up the disc: misaligned accretion on to a binary

    NASA Astrophysics Data System (ADS)

    Nixon, Chris; King, Andrew; Price, Daniel

    2013-09-01

    In a recent paper, we have shown that the evolution of a misaligned disc around a spinning black hole can result in tearing the disc into many distinct planes. Tearing discs with random orientations produce direct dynamical accretion on to the hole in ≈70 per cent of all cases. Here, we examine the evolution of a misaligned disc around a binary system. We show that these discs are susceptible to tearing for almost all inclinations. We also show that tearing of the disc can result in a significant acceleration of the disc evolution and subsequent accretion on to the binary - by factors up to 104 times that of a coplanar prograde disc with otherwise identical parameters. This provides a promising mechanism for driving mergers of supermassive black hole (SMBH) binaries on time-scales much shorter than a Hubble time. Disc tearing also suggests new observational signatures of accreting SMBH binaries and other systems such as protostellar binaries.

  14. 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

  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. Transcatheter mitral valve repair with mitraclip for significant mitral regurgitation long after heart transplantion.

    PubMed

    Ferraro, Paolo; Biondi-Zoccai, Giuseppe; Giordano, Arturo

    2016-07-01

    The role of transcatheter mitral valve repair with MitraClip implantation is becoming increasingly important for high-risk surgical patients with significant mitral regurgitation. Eligibility criteria for MitraClip are however rather strict, and the risk-benefit balance of this device in off-label settings remains unclear. Patients with prior heart transplantation may represent particularly challenging candidates for MitraClip, given their peculiar atrial anatomy. We hereby present the case of a 72-year-old gentleman with prior heart transplantation and significant mitral regurgitation who, after heart team consensus, was referred to us for MitraClip implantation. After careful planning, we were able to successfully implant two clips, achieving a significant improvement in the severity of the mitral regurgitation. Similarly favorable findings were confirmed at 3-month clinical and transthoracic/transesophageal echocardiographic follow-up. This clinical vignette highlights the key procedural milestones for successfully implanting MitraClip in patients with significant mitral regurgitation and prior heart transplantation. © 2015 Wiley Periodicals, Inc. PMID:26333048

  17. Cardiogenic shock: A look at acute functional mitral incompetence.

    PubMed

    Steyn, F A; Vosloo, J; Naude, H; Steyn, A J

    2016-08-01

    A 44-year-old man presented with cardiogenic shock secondary to acute functional mitral incompetence as well as septic shock related to pneumonia. The patient deteriorated haemodynamically despite adequate medical therapy. An echocardiogram revealed a massive mitral incompetence and an ejection fraction of 32%. An intra-aortic balloon pump was placed and the patient improved dramatically. On day 6 after admission the echocardiogram was repeated, revealing a mild mitral incompetence and an ejection fraction of 58%. PMID:27499404

  18. Mitral valve surgery - minimally invasive

    MedlinePlus

    ... There are two main types of new valves: Mechanical, made of man-made materials, such as titanium ... Mechanical heart valves do not fail often. However, blood clots can develop on them. If a blood ...

  19. Transjugular approach for transcatheter closure of mitral paraprosthetic leak.

    PubMed

    Joseph, George; Thomson, Viji Samuel

    2009-11-15

    Transcatheter closure of mitral paraprosthetic leak (PPL) using femoral antegrade transseptal or retrograde approach is often unsuccessful when the involved part of the mitral annulus is difficult to access or when the left atrium is large. We report the successful use of jugular venous approach to perform transseptal antegrade PPL closure in a 49-year-old male with mitral PPL located in the anteromedial part of the annulus. This technique could serve as a useful alternative in patients in whom transcatheter closure of mitral PPL is technically difficult. PMID:19626688

  20. Effect of the mitral valve on diastolic flow patterns

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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.

  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. Secundum atrial septal defect and mitral valve incompetence.

    PubMed

    Murray, G F; Wilcox, B R

    1975-08-01

    Mitral regurgitation associated with secundum atrial septal defect is described in 4 patients, each with a different mitral lesion: rheumatic valvular disease, congenitally cleft valve, subacute bacterial endocarditis with disruption of the chordae tendineae, and traumatic valve rupture. The pathological spectrum of mitral valve disease associated with atrial septal defect is reviewed, and it is suggested that structural abnormality of the mitral valve may accompany the atrial septal defect. More general awareness of this association will allow the surgeon more accuracy in defining and repairing this rather unusual combination of lesions. PMID:1164060

  3. 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

  4. 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

  5. Human Cardiac Function Simulator for the Optimal Design of a Novel Annuloplasty Ring with a Sub-valvular Element for Correction of Ischemic Mitral Regurgitation.

    PubMed

    Baillargeon, Brian; Costa, Ivan; Leach, Joseph R; Lee, Lik Chuan; Genet, Martin; Toutain, Arnaud; Wenk, Jonathan F; Rausch, Manuel K; Rebelo, Nuno; Acevedo-Bolton, Gabriel; Kuhl, Ellen; Navia, Jose L; Guccione, Julius M

    2015-06-01

    Ischemic mitral regurgitation is associated with substantial risk of death. We sought to: (1) detail significant recent improvements to the Dassault Systèmes human cardiac function simulator (HCFS); (2) use the HCFS to simulate normal cardiac function as well as pathologic function in the setting of posterior left ventricular (LV) papillary muscle infarction; and (3) debut our novel device for correction of ischemic mitral regurgitation. We synthesized two recent studies of human myocardial mechanics. The first study presented the robust and integrative finite element HCFS. Its primary limitation was its poor diastolic performance with an LV ejection fraction below 20% caused by overly stiff ex vivo porcine tissue parameters. The second study derived improved diastolic myocardial material parameters using in vivo MRI data from five normal human subjects. We combined these models to simulate ischemic mitral regurgitation by computationally infarcting an LV region including the posterior papillary muscle. Contact between our novel device and the mitral valve apparatus was simulated using Dassault Systèmes SIMULIA software. Incorporating improved cardiac geometry and diastolic myocardial material properties in the HCFS resulted in a realistic LV ejection fraction of 55%. Simulating infarction of posterior papillary muscle caused regurgitant mitral valve mechanics. Implementation of our novel device corrected valve dysfunction. Improvements in the current study to the HCFS permit increasingly accurate study of myocardial mechanics. The first application of this simulator to abnormal human cardiac function suggests that our novel annuloplasty ring with a sub-valvular element will correct ischemic mitral regurgitation. PMID:25984248

  6. Prosthetic lumbar disc replacement for degenerative disc disease.

    PubMed

    Kulkarni, Arvind G; Diwan, Ashish D

    2005-12-01

    Mechanical articulated device to replace intervertebral disc as a treatment for low back pain secondary to disc degeneration has emerged as a promising tool for selected patients. The potential advantages are prevention of adjacent segment degeneration, maintenance of mobility as well as avoidance of all the complications associated with fusion. The short-term results have been comparable to that of fusion, a few mid-term results have shown mixed outcome, but information on long-term results and performance are not available at present. The rationale for lumbar disc arthroplasty, indications, contraindications, the various artificial devices in the market and the concepts intrinsic to each of them, basic technique of insertion, complications are discussed and a brief summary of our experience with one of the devices is presented. PMID:16565543

  7. 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

  8. Cholecystokinin: An Excitatory Modulator of Mitral/Tufted Cells in the Mouse Olfactory Bulb

    PubMed Central

    Ma, Jie; Dankulich-Nagrudny, Luba; Lowe, Graeme

    2013-01-01

    Cholecystokinin (CCK) is widely distributed in the brain as a sulfated octapeptide (CCK-8S). In the olfactory bulb, CCK-8S is concentrated in two laminae: an infraglomerular band in the external plexiform layer, and an inframitral band in the internal plexiform layer (IPL), corresponding to somata and terminals of superficial tufted cells with intrabulbar projections linking duplicate glomerular maps of olfactory receptors. The physiological role of CCK in this circuit is unknown. We made patch clamp recordings of CCK effects on mitral cell spike activity in mouse olfactory bulb slices, and applied immunohistochemistry to localize CCKB receptors. In cell-attached recordings, mitral cells responded to 300 nM –1 µM CCK-8S by spike excitation, suppression, or mixed excitation-suppression. Antagonists of GABAA and ionotropic glutamate receptors blocked suppression, but excitation persisted. Whole-cell recordings revealed that excitation was mediated by a slow inward current, and suppression by spike inactivation or inhibitory synaptic input. Similar responses were elicited by the CCKB receptor-selective agonist CCK-4 (1 µM). Excitation was less frequent but still occurred when CCKB receptors were blocked by LY225910, or disrupted in CCKB knockout mice, and was also observed in CCKA knockouts. CCKB receptor immunoreactivity was detected on mitral and superficial tufted cells, colocalized with Tbx21, and was absent from granule cells and the IPL. Our data indicate that CCK excites mitral cells postsynaptically, via both CCKA and CCKB receptors. We hypothesize that extrasynaptic CCK released from tufted cell terminals in the IPL may diffuse to and directly excite mitral cell bodies, creating a positive feedback loop that can amplify output from pairs of glomeruli receiving sensory inputs encoded by the same olfactory receptor. Dynamic plasticity of intrabulbar projections suggests that this could be an experience-dependent amplification mechanism for tuning and

  9. Role of percutaneous mitral valve repair in the contemporary management of mitral regurgitation.

    PubMed

    Rana, Bushra S; Calvert, Patrick A; Punjabi, Prakash P; Hildick-Smith, David

    2015-10-01

    Percutaneous mitral valve (MV) repair has been performed in over 20,000 patients worldwide. As clinical experience in this technique grows indications for its use are being defined. Mitral regurgitation (MR) encompasses a complex heterogeneous group and its treatment is governed by determining a clear understanding of the underlying aetiology. Surgical MV repair remains the gold standard therapy for severe MR. However in select groups of high-risk surgical patients, a percutaneous approach to MV repair is establishing its role. This review gives an overview of the published data in percutaneous MV repair and its impact on the contemporary management of MR. PMID:26101091

  10. 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.

  11. Laser engineering of spine discs

    NASA Astrophysics Data System (ADS)

    Sobol, E.; Zakharkina, O.; Baskov, A.; Shekhter, A.; Borschenko, I.; Guller, A.; Baskov, V.; Omelchenko, A.; Sviridov, A.

    2009-04-01

    The laser engineering of intervertebral discs is one of the branch of medical physics aimed at the development of minimally invasive laser medical techniques based on the effect of the controlled (time- and space-modulated) laser radiation on the structure and the field of mechanical stress of biological tissues. A new method for the laser engineering of the intervertebral discs and the differences of this approach from the existing physical methods of medical treatment are considered. The newly formed tissues of animals and humans are hystologically studied. Possible regeneration processes are discussed. A control system that provides for the treatment efficiency and safety is developed. The new laser medical equipment that is designed for the laser engineering of intervertebral discs is described, and the corresponding results of the clinical application are presented.

  12. [Percutaneous mitral valve annuloplasty with the carillon mitral contour system by cardiac dimensions. A minimally invasive therapeutic option for the treatment of severe functional mitral valve regurgitation].

    PubMed

    Degen, Hubertus; Lickfeld, Thomas; Stoepel, Carsten; Haude, Michael

    2009-09-01

    Morbidity in patients with systolic heart failure is significantly increased by functional mitral valve regurgitation. In addition to pharmaceutical treatment or surgical reconstruction of the impaired valve, minimally invasive procedures have continuously advanced into the focus of interest. The Carillon Mitral Contour System (Cardiac Dimensions) is a new catheter-based method to converge dehiscent mitral valve leaflets with implantation of a nitinol clip into the coronary sinus, leading to a closer approach of the valve leaflets with subsequent decrease in mitral regurgitation. The device is implanted via a central venous catheter, using a special delivery system under fluoroscopy. The immediate success of minimizing mitral valve regurgitation is verified by online transesophageal echocardiography (TEE), device-related impairment of perfusion of contiguous coronary vessels is ruled out by coronary angiography performed simultaneously during deployment of the device. As soon as reduction of the mitral valve regurgitation is demonstrated in TEE, the Carillon System is disconnected from the delivery system, before, however, the Carillon device can be withdrawn into the delivery system as necessary. Following the successful implantation of the Carillon Mitral Contour System, a left ventricular lead for cardiac resynchronization therapy can still be successfully placed alongside through the coronary sinus. PMID:19784563

  13. 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

  14. Leaflet escape in a revised Edwards-Duromedics mitral prosthesis.

    PubMed

    Mert, Murat; Ozkara, Ahmet; Hatemi, AliCan

    2003-07-01

    The original Duromedics-Edwards bileaflet valve was withdrawn from the market in 1988 after 12 reports of leaflet escape. The leaflet was modified by the manufacturer, and the revised Edwards-Duromedics and Edwards TEKNA valves were introduced in 1990 and 1993, respectively. However, problems of leaflet escape have now been reported with the new models. A case is reported of sudden leaflet fracture of a revised Duromedics mitral valve 86 months after implantation; this was managed successfully by emergency replacement with a St. Jude Medical mechanical prosthesis. The fracture had occurred transversely, with the two fragments embolizing bilaterally to the right common iliac and left external iliac arteries. In the absence of an exact diagnosis, but with a high index of suspicion, the key to survival of patients with leaflet escape is immediate reoperation. PMID:12918855

  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. Perivalvular leakage 25 years after initial mitral valve replacement with a Björk-Shiley prosthesis.

    PubMed

    Minami, Hiroya; Asada, Tatsuro; Gan, Kunio

    2008-09-01

    An 80-year-old woman had undergone initial mitral valve replacement using a Björk-Shiley mechanical valve owing to mitral stenosis 25 years earlier. Suddenly, she had anemia and an increased lactic dehydrogenase (LDH) level. Transesophageal echography (TEE) showed perivalvular leakage. In a redo operation, two side-by-side stitches of the valve on the posterior annulus were loosened without cutting and the sewing cuff at that site was floated over the annulus, leading to the perivalvular leakage. The valve was easily removed; and round, hard, degenerative calcified tissue composed of remnant mitral valve in the suture site during the initial operation was found just under the sewing cuff. After resection of this calcified round tissue, a 25-mm bioprosthesis was put in place. Her postoperative recovery was uneventful, and 47 days after surgery she was discharged without perivalvular leakage or anemia. PMID:18791673

  17. Video Discs in Education.

    ERIC Educational Resources Information Center

    Barker, Philip

    1986-01-01

    This discussion of the use of images in learning processes focuses on recent developments in optical storage disc technology, particularly compact disc read-only (CD-ROM) and optical video discs. Interactive video systems and user interfaces are described, and applications in education and industry in the United Kingdom are reviewed. (Author/LRW)

  18. 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.

  19. Mitral Regurgitation (Beyond the Basics)

    MedlinePlus

    ... American Heart Association and American College of Cardiology ( table 1 ) [ 3 ]: ● A mechanical valve is suggested for ... Guidelines. J Am Coll Cardiol 2014; 63:e57. Table used with the permission of Elsevier Inc. All ...

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

    PubMed

    Hakan, Tayfun; 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. 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

  2. Double-orifice mitral valve associated with atrioventricular canal defects

    PubMed Central

    Rhissassi, Jaafar; El Malki, Hicham; Benmessaoud, Fatima Azzahra; El Kandoussi, Tahar; Laaroussi, Mohamed

    2016-01-01

    A 4 year-old male presented with effort dyspnea, and was diagnosed as atrioventricular canal defects. This finding was confirmed by open heart surgery, and a congenital double orifice mitral valve was discovered. The septal defect was closed but the double orifice mitral valve was respected because of the absence of hemodynamic disturbance. We report this case with review of literature. PMID:27347288

  3. [Mitral valve replacement following myomectomy for idiopathic hypertrophic subaortic stenosis].

    PubMed

    Shigenobu, M; Arai, S; Okada, M; Imai, S; Senoo, Y; Teramoto, S

    1989-08-01

    A patient is reported with IHSS where mitral valve replacement was performed 3 years following myomectomy because of a residual pressure gradient of left ventricular outflow tract. After mitral valve replacement, the left ventricular outflow tract obstruction was almost completely relieved not only at rest but also at provocation by isoproterenol. The patient successfully returned to work with no symptoms. PMID:9301943

  4. 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

  5. Left ventricular post-infraction pseudoaneurysm mimicking mitral valve endocarditis

    PubMed Central

    2013-01-01

    In this report we present a patient who was initially diagnosed as suffering from mitral valve endocarditis. The proper use of diagnostic modalities revealed a pseudo aneurysm of the left ventricle which was mimicking mitral valve vegetations. This allowed better planning of the subsequent operation. The optimal preoperative diagnostic studies are discussed along with the proper surgical treatment. PMID:24228621

  6. Left ventricular post-infraction pseudoaneurysm mimicking mitral valve endocarditis.

    PubMed

    Dedeilias, Panagiotis; Koukis, Ioannis; Roussakis, Antonios; Tsipas, Pantelis; Rouska, Effie

    2013-01-01

    In this report we present a patient who was initially diagnosed as suffering from mitral valve endocarditis. The proper use of diagnostic modalities revealed a pseudo aneurysm of the left ventricle which was mimicking mitral valve vegetations. This allowed better planning of the subsequent operation. The optimal preoperative diagnostic studies are discussed along with the proper surgical treatment. PMID:24228621

  7. Rat olfactory bulb mitral cells receive sparse glomerular inputs.

    PubMed

    Fantana, Antoniu L; Soucy, Edward R; Meister, Markus

    2008-09-11

    Center-surround receptive fields are a fundamental unit of brain organization. It has been proposed that olfactory bulb mitral cells exhibit this functional circuitry, with excitation from one glomerulus and inhibition from a broad field of glomeruli within reach of the lateral dendrites. We investigated this hypothesis using a combination of in vivo intrinsic imaging, single-unit recording, and a large panel of odors. Assuming a broad inhibitory field, a mitral cell would be influenced by >100 contiguous glomeruli and should respond to many odors. Instead, the observed response rate was an order of magnitude lower. A quantitative model indicates that mitral cell responses can be explained by just a handful of glomeruli. These glomeruli are spatially dispersed on the bulb and represent a broad range of odor sensitivities. We conclude that mitral cells do not have center-surround receptive fields. Instead, each mitral cell performs a specific computation combining a small and diverse set of glomerular inputs. PMID:18786363

  8. Hydrodynamic instability in warped astrophysical discs

    NASA Astrophysics Data System (ADS)

    Ogilvie, Gordon I.; Latter, Henrik N.

    2013-08-01

    Warped astrophysical discs are usually treated as laminar viscous flows, which have anomalous properties when the disc is nearly Keplerian and the viscosity is small: fast horizontal shearing motions and large torques are generated, which cause the warp to evolve rapidly, in some cases at a rate that is inversely proportional to the viscosity. However, these flows are often subject to a linear hydrodynamic instability, which may produce small-scale turbulence and modify the large-scale dynamics of the disc. We use a warped shearing sheet to compute the oscillatory laminar flows in a warped disc and to analyse their linear stability by the Floquet method. We find widespread hydrodynamic instability deriving from the parametric resonance of inertial waves. Even very small, unobservable warps in nearly Keplerian discs of low viscosity can be expected to generate hydrodynamic turbulence, or at least wave activity, by this mechanism.

  9. Modification of a stented bovine jugular vein conduit (melody valve) for surgical mitral valve replacement.

    PubMed

    Abdullah, Ibrahim; Ramirez, Francisco Boye; McElhinney, Doff B; Lock, James E; del Nido, Pedro J; Emani, Sitaram

    2012-10-01

    We report the use of a Melody valve as a surgical implant in the mitral position in 2 infants, one with severe mitral regurgitation and another with mitral stenosis, where other prostheses are not small enough to be implanted in the mitral position nor expandable as the child grows. PMID:23006723

  10. Premeasured Chordal Loops for Mitral Valve Repair.

    PubMed

    Gillinov, Marc; Quinn, Reed; Kerendi, Faraz; Gaudiani, Vince; Shemin, Richard; Barnhart, Glenn; Raines, Edward; Gerdisch, Marc W; Banbury, Michael

    2016-09-01

    Premeasured expanded polytetrafluoroethylene chordal loops with integrated sutures for attachment to the papillary muscle and leaflet edges facilitate correction of mitral valve prolapse. Configured as a group of 3 loops (length range 12 to 24 mm), the loops are attached to a pledget that is passed through the papillary muscle and tied. Each of the loops has 2 sutures with attached needles; these needles are passed through the free edge of the leaflet and then the sutures are tied to each other, securing the chordal loop to the leaflet. PMID:27549563

  11. 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

  12. Stress myocardial imaging in patients with mitral valve prolapse: evidence of a perfusion abnormality

    SciTech Connect

    Butman, S.; Chandraratna, P.A.; Milne, N.; Olson, H.; Lyons, K.; Aronow, W.S.

    1982-01-01

    Twenty-four patients with mitral valve prolapse underwent cardiac catheterization, exercise testing, and exercise /sup 201/T1 scintigraphy. Of 10 patients with coronary artery disease, six had abnormal scintigrams. Two of these six had exercise-induced reversible defects, two had defects that persisted during redistribution, and two had both reversible and persistent defects. Of 14 patients with normal coronary arteries, five had negative scintigrams. Of the remaining nine patients, two had exercise-induced defects, and seven (50%) had defects involving the inferior or posterior wall that persisted during redistribution. Possible mechanisms for this latter finding are discussed. In contrast to previous reports, exercise /sup 201/T1 scintigraphy was not entirely successful in identifying patients with coronary artery disease in our patients with mitral valve prolapse.

  13. 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

  14. 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

  15. Pathogenesis of acute ischemic mitral regurgitation in three dimensions.

    PubMed

    Gorman, R C; McCaughan, J S; Ratcliffe, M B; Gupta, K B; Streicher, J T; Ferrari, V A; St John-Sutton, M G; Bogen, D K; Edmunds, L H

    1995-04-01

    Changes in the geometric and intravalvular relationships between subunits of the ovine mitral valve were measured before and after acute posterior wall myocardial infarction in three dimensions by means of sonomicrometry array localization. In 13 sheep, nine sonomicrometer transducers were attached around the mitral anulus and to the tip and base of each papillary muscle. Five additional transducers were placed on the epicardium. Snares were placed around three branches of the circumflex coronary artery. One to 2 weeks later, echocardiograms, dimension measurements, and left ventricular pressures were obtained before and after the coronary arteries were occluded. Data were obtained from seven sheep. Coronary occlusion infarcted 32% of the posterior left ventricle and produced 2 to 3+ mitral regurgitation by Doppler color flow mapping. Multidimensional scaling of dimension measurements obtained from sonomicrometry transducers produced three-dimensional spatial coordinates of each transducer location throughout the cardiac cycle before and after infarction and onset of mitral regurgitation. After posterior infarction, the mitral anulus enlarges asymmetrically along the posterior anulus, and the tip of the posterior papillary muscle moves 1.5 +/- 0.3 mm closer to the posterior commissure at end-systole. The posterior papillary muscle also elongates 1.9 +/- 0.3 mm at end-systole. The left ventricle enlarges asymmetrically and ventricular torsion along the long axis changes. The development of postinfarction mitral regurgitation appears to be the consequence of multiple small changes in ventricular shape and contractile deformation and in the spatial relationship of mitral valvular subunits. PMID:7715215

  16. Mitral valve disease: a cardiologic-surgical interaction.

    PubMed

    Barlow, J B

    1996-10-01

    The respective roles of cardiologist and cardiac surgeon in the operative management of any specific case of mitral valve disease are variable. The range from the prevalent complete predominance of the surgeon through meaningful interaction between the two, concerning the timing and type of surgery, to predominance of the cardiologist when the surgeon accepts a role of technician. There are a number of scenarios in mitral valve surgery in which a reduced risk of postoperative hospital mortality and morbidity, by performing the simplest and shortest procedure, have to be balanced against enhanced peri-operative problems when other aspects are addressed that improve, sometimes markedly, the long-term prognosis. It is argued that a mildly stenotic aortic valve should often be replaced at the time of mitral valve surgery; that despite technical difficulties and a variable long-term postoperative course, surgeons should continue to repair rather than replace the mitral valves of young patients with severe mitral regurgitation despite the invariable presence of active rheumatic carditis; and that excess leaflet tissue and lax chordae in cases of degenerative mitral regurgitation are casually related to multifocal and potentially fatal ventricular ectopy. The crucial but neglected role of an organically abnormal tricuspid anulus in allowing dilatation and hence tricuspid regurgitation in patients with rheumatic mitral valve disease is considered in some detail. Such dilatation may occur late after mitral valve surgery for rheumatic disease, has generally and incorrectly been regarded as "functional" tricuspid regurgitation, contributes importantly to the postoperative "restriction-dilatation syndrome" and can be effectively prevented, or when once established then surgically managed, by a modified De Vega anuloplasty. Finally it is believed that, unlike mitral balloon valvuloplasty in selected instances, successful tricuspid balloon valvuloplasty can never be accomplished

  17. Clinical and Radiological Characteristics of Lumbosacral Lateral Disc Herniation in Comparison With Those of Medial Disc Herniation

    PubMed Central

    Lee, Jung Hwan; Lee, Sang-Ho

    2016-01-01

    Abstract Lateral disc herniation (foraminal and extra foraminal) has clinical characteristics that are different from those of medial disc herniation (central and subarticular), including older age, more frequent radicular pain, and neurologic deficits. This is supposedly because lateral disc herniation mechanically irritates or compresses the exiting nerve root or dorsal root ganglion inside of a narrow canal more directly than medial disc herniation. The purpose of this study was to investigate clinical and radiological characteristics of lateral disc herniation in comparison with medial disc herniation. The 352 subjects diagnosed with localized lumbosacral disc herniation and followed up for at least 12 months after completion of treatment were included and divided into medial and lateral disc herniation groups, according to the anatomical location of the herniated disc in axial plain of magnetic resonance image. Clinical and radiological data were obtained and compared between the two groups. The lateral group included 74 (21%) patients and the medial group included 278 (79%). Mean age of the lateral group was significantly higher than that in the medial group. The lateral group showed a significantly larger proportion of patients with radiating leg pain and multiple levels of disc herniations than the medial group. No significant differences were found in terms of gender, duration of pain, pretreatment numeric rating scale, severity of disc herniation (protrusion and extrusion), and presence of weakness in leg muscles. The proportion of patients who underwent surgery was not significantly different between the 2 groups. However, the proportion of patients who accomplished successful pain reduction after treatment was significantly smaller in the lateral than in the medial group. In conclusion, patients with lateral disc herniation were older and had larger proportion of radiating leg pain than those with medial disc herniation. Lateral disc herniation was more

  18. Clinical and Radiological Characteristics of Lumbosacral Lateral Disc Herniation in Comparison With Those of Medial Disc Herniation.

    PubMed

    Lee, Jung Hwan; Lee, Sang-Ho

    2016-02-01

    Lateral disc herniation (foraminal and extra foraminal) has clinical characteristics that are different from those of medial disc herniation (central and subarticular), including older age, more frequent radicular pain, and neurologic deficits. This is supposedly because lateral disc herniation mechanically irritates or compresses the exiting nerve root or dorsal root ganglion inside of a narrow canal more directly than medial disc herniation. The purpose of this study was to investigate clinical and radiological characteristics of lateral disc herniation in comparison with medial disc herniation. The 352 subjects diagnosed with localized lumbosacral disc herniation and followed up for at least 12 months after completion of treatment were included and divided into medial and lateral disc herniation groups, according to the anatomical location of the herniated disc in axial plain of magnetic resonance image. Clinical and radiological data were obtained and compared between the two groups. The lateral group included 74 (21%) patients and the medial group included 278 (79%). Mean age of the lateral group was significantly higher than that in the medial group. The lateral group showed a significantly larger proportion of patients with radiating leg pain and multiple levels of disc herniations than the medial group. No significant differences were found in terms of gender, duration of pain, pretreatment numeric rating scale, severity of disc herniation (protrusion and extrusion), and presence of weakness in leg muscles. The proportion of patients who underwent surgery was not significantly different between the 2 groups. However, the proportion of patients who accomplished successful pain reduction after treatment was significantly smaller in the lateral than in the medial group. In conclusion, patients with lateral disc herniation were older and had larger proportion of radiating leg pain than those with medial disc herniation. Lateral disc herniation was more

  19. Robotic Excision of a Papillary Fibroelastoma of the Mitral Chordae.

    PubMed

    Arsalan, Mani; Smith, Robert L; Squiers, John J; Wang, Alex; DiMaio, J Michael; Mack, Michael J

    2016-06-01

    Papillary fibroelastomas of the mitral chordae tendineae are rare, primary benign tumors. They are either incidentally diagnosed during echocardiography or discovered after transient ischemic attack, stroke, or myocardial infarction. Removal of papillary fibroelastomas should be considered, given the increased risk for embolization causing cerebrovascular accident or mortality in patients with echocardiographic evidence of papillary fibroelastoma not undergoing surgical procedures. Although fibroelastoma removal can be performed in most cases without disrupting mitral valve competency, sternotomy and minithoracotomy are the typical approaches for excision. Herein, we report the first robotic excision of a mitral chord papillary fibroelastoma. PMID:27211977

  20. Mitral and Aortic Valvulitis in Primary Chronic Septic Endocarditis.

    PubMed

    Bushmanova, G M; Zorina, I G; Nikityuk, D B; Nepomnyashchikh, R D; Lapii, G A; Postnikova, O A; Semenov, D E

    2015-05-01

    Results of long-term prospective follow-up of patients with early stages of mitral and aortic valvulitis and primary chronic septic endocarditic are presented. Clinical diagnostics of the diseases is described and the key role is assigned to pathognomic (absolute) clinical symptoms. The tendency to progressive fibrosis of endocardial structures with subsequent gradual development of valve dysfunction and stenosis (especially for the mitral valve) is revealed. It is shown that early treatment increases the effective valve area and promotes reversion of mitral stenosis. The possibility of early diagnostics of primary chronic septic endocarditis in combination with adequate etiopathogenetic therapy provide the basis for prevention of acquired valvular disease. PMID:26033580

  1. Mitral stenosis: I. Anatomical, physiological, and clinical considerations.

    PubMed

    Glancy, D Luke

    2003-01-01

    Because of the dramatic decline in the incidence of acute rheumatic fever in the United States and much of the developed world over the past 70 years, mitral stenosis, once a common valvular problem, is now distinctly uncommon in many countries. Nevertheless, because mitral stenosis maintains a high prevalence in developing countries and among emigrants from those countries to the United States, continued awareness of the condition is warranted. Furthermore, failure to recognize mitral stenosis not only precludes many effective therapies but in so doing may result in serious complications. PMID:12778992

  2. 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. PMID:22859687

  3. Turbulence-induced disc formation in strongly magnetized cloud cores

    NASA Astrophysics Data System (ADS)

    Seifried, D.; Banerjee, R.; Pudritz, R. E.; Klessen, R. S.

    2013-07-01

    We present collapse simulations of strongly magnetized, turbulent molecular cloud cores with masses ranging from 2.6 to 1000 M⊙ in order to study the influence of the initial conditions on the turbulence-induced disc formation mechanism proposed recently by Seifried et al. We find that Keplerian discs are formed in all cases independently of the core mass, the strength of turbulence or the presence of global rotation. The discs appear within a few kyr after the formation of the protostar, are 50-150 au in size, and have masses between 0.05 and a few 0.1 M⊙. During the formation of the discs the mass-to-flux ratio stays well below the critical value of 10 for Keplerian disc formation. Hence, flux-loss alone cannot explain the formation of Keplerian discs. The formation of rotationally supported discs at such early phases is rather due to the disordered magnetic field structure and due to turbulent motions in the surroundings of the discs, two effects lowering the classical magnetic braking efficiency. Binary systems occurring in the discs are mainly formed via the disc capturing mechanism rather than via disc fragmentation, which is largely suppressed by the presence of magnetic fields.

  4. Development of mitral stenosis after single MitraClip insertion for severe mitral regurgitation.

    PubMed

    Cockburn, James; Fragkou, Paraskevi; Hildick-Smith, David

    2014-02-01

    We report the first case of mitral stenosis following Mitra-Clip insertion in a patient with symptomatic NYHA IV heart failure, secondary to severe mitral regurgitation (MR). A 79-year-old female with a history of prior aortic valve replacement underwent percutaneous mitral valve (MV) repair. A single clip was advanced coaxially down onto the MV under TOE guidance, with the anterior and posterior leaflets clipped together between A2 and P2. TOE confirmed a significant reduction in MR (grade 4 to grade 1). Despite initial symptomatic relief, she represented 3 months later with similar symptoms. Repeat TOE confirmed a well positioned Mitra-Clip with mild residual MR. However, the possibility of significant mitral stenosis was raised due to the presence of significant turbulence through the bi-orifice valve, with a peak gradient of 25 mm Hg. In addition there was evidence of severe functional tricuspid valve (TV) regurgitation with elevated pulmonary artery pressures (PAP 90 mm Hg), confirmed on subsequent right heart catheterization. After repeated heart team discussions and a failure of optimal medical therapy, and despite a logistic EuroScore of 35.5, minimally invasive surgical replacement of the MV and simultaneous TV repair was undertaken via a right thoracotomy. Despite procedural success and initial good postoperative response, the patient died subsequently from a combination of hospital-acquired pneumonia and significant gastrointestinal bleeding (post operative day 35). Mitra-Clip is a promising novel approach to MV repair. The establishment of further clinical and echocardiographic based selection criteria will help identify the correct patients for this treatment. PMID:23703973

  5. Near-infrared Raman spectroscopy to detect the calcification of the annular mitral valve

    NASA Astrophysics Data System (ADS)

    Rocha, Rick; Otero, E. P.; Costa, M. S.; Villaverde, Antonio G. J. B.; Pomerarantzeff, P. M.; Pacheco, Marcos T. T.

    2004-10-01

    Cardiac valves are subjected to high repetitive mechanical stresses, particularly at the hinge points of the cusps and leaflets due to the over 40 millions cardiac cycles per year. These delicate structures can suffer cumulative lesions, complicated by the deposition of calcium phosphate mineral, which may lead to clinically important disease. Near Infrared Raman Spectroscopy gives important information about biological tissues composition and it is being used for diagnosis of some pathologies. The aim of this work was to detect trough the use of the Raman Spectroscopy technique the mitral annular calcification. A Ti:sapphire laser operating at the near infrared wavelength of 785 nm was used for the excitation of the valve samples and the Raman radiation was detected by an optical spectrometer with a CCD liquid nitrogen cooled detector. In all, ten samples of normal and pathologic tissues were studied. They were approximately squared with the lateral size of 5 mm. It was observed that the Raman spectrum of the calcified mitral valve showed different behavior, when compared to normal tissues. Results indicate that this technique could be used to detect the deposition of the calcium phosphate mineral over the mitral valve.

  6. Vortices formed on the mitral valve tips aid normal left ventricular filling

    NASA Astrophysics Data System (ADS)

    Vlachos, Pavlos

    2011-11-01

    For the left ventricle to function as an effective pump it must be able to fill from a low left atrial pressure. However, this ability is lost in patients with heart failure. We investigated the fluid dynamics of the left ventricle filling by imaging the blood flow in patients with healthy and impaired diastolic function, using 2D phase contrast magnetic resonance imaging and we quantified the intraventricular pressure gradients and the strength and location of the formed vortices. We found that during early filling in normal subjects, prior to the opening of the mitral valve the flow moves towards the apex and subsequently at the time of the opening of the valve the rapid movement of the mitral annulus away from the left ventricle apex enhances the formation of a vortex ring at the mitral valve tips. Instead of being a passive byproduct of the process as was previously believed, this vortex ring facilitates filling by reducing convective losses and enhancing the function of the left ventricle as a suction pump. Impairment of this mechanism contributes to diastolic dysfunction, with the left ventricle filling becoming dependent on left atrial pressure, and eventually leading to heart failure. John R. Jones Professor

  7. Surgical Treatment of Anomalous Origin of Right Coronary Artery in a Patient with Mitral Stenosis

    PubMed Central

    Refatllari, Ali; Likaj, Ermal; Dumani, Selman; Hasimi, Endri; Goda, Artan

    2016-01-01

    BACKGROUND: An anomalous origin of the right coronary artery is rarely observed, with a reported incidence between 0.026% and 0.25%. This condition is often completely asymptomatic and is found incidentally during angiographic evaluation for other cardiac diseases. However some patients present with exertion angina or sudden death. Surgical treatment in patients with anomalous RCA is still controversial. Treatment can be conservative, angioplasty or surgery. CASE PRESENTATION: A 59-year-old man was admitted with severe mitral stenosis. He complained exertion and rest dyspnea, NYHA III class. He had sequels of embolic stroke, results of left atrial thrombus. Echocardiography showed calcified severe mitral stenosis with mitral orifice area of 1.1 square centimeters with PSPAP 60 mmHg and normal LV function. Routine coronary angiography before surgery showed aberrant origin of RCA from the left sinus of Valsalva with 90% stenosis at his origin. Multi-slice computed tomography proved the diagnosis of anomalous RCA arising from the left sinus of Valsalva and taking an inter-arterial course between the aorta and pulmonary artery. The patient underwent mitral valve replacement with mechanical St. Jude prosthesis No 29 and saphenous vein graft to RCA. We chose by-pass grafting techniques because after aortotomy, RCA was too close to LMCA, intramural course was too short and stenosis of RCA was outside of aortic wall. The patient’s perioperative course was without complications and patient was discharged on the seventh postoperative day. CONCLUSION: Correction of anomalous of the origin of right coronary artery is mandatory in cases where patient has to be operated for other cardiac causes. PMID:27275346

  8. Degenerative Mitral Stenosis: Unmet Need for Percutaneous Interventions.

    PubMed

    Sud, Karan; Agarwal, Shikhar; Parashar, Akhil; Raza, Mohammad Q; Patel, Kunal; Min, David; Rodriguez, Leonardo L; Krishnaswamy, Amar; Mick, Stephanie L; Gillinov, A Marc; Tuzcu, E Murat; Kapadia, Samir R

    2016-04-19

    Degenerative mitral stenosis (DMS) is an important cause of mitral stenosis, developing secondary to severe mitral annular calcification. With the increase in life expectancy and improved access to health care, more patients with DMS are likely to be encountered in developed nations. These patients are generally elderly with multiple comorbidities and often are high-risk candidates for surgery. The mainstay of therapy in DMS patients is medical management with heart rate control and diuretic therapy. Surgical intervention might be delayed until symptoms are severely limiting and cannot be managed by medical therapy. Mitral valve surgery is also challenging in these patients because of the presence of extensive calcification. Hence, there is a need to develop an alternative percutaneous treatment approach for patients with DMS who are otherwise inoperable or at high risk for surgery. In this review, we summarize the available data on the epidemiology of DMS and diagnostic considerations and current treatment strategies for these patients. PMID:27142604

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

    MedlinePlus Videos and Cool Tools

    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 © 2016 BroadcastMed, Inc. All rights reserved.

  10. [Immune state in athletes with mitral valve prolapse].

    PubMed

    Maslennikova, O M; Reznichenko, T A; Firsakova, V Iu

    2013-01-01

    The authors evaluated immune state in 541 professional athletes. The athletes with vitral valve prolapse (132 subjects) appeared to have immune changes - lower immunoglobulines levels, general leucocytes count, if compared to the athletes without mitral valve prolapse. PMID:24340766

  11. Mitral valve involvement as a predominant feature of cardiac amyloidosis

    PubMed Central

    Viswanathan, Girish; Williams, James; Slinn, Simon; Campbell, Philip

    2010-01-01

    Cardiac involvement in systemic amyloidosis carries poor prognosis with a median survival of 5 months.1 The authors report an unusual presentation of cardiac amyloidosis in the form of predominant mitral regurgitation. The patient responded very well to medical therapy with subsequent improvement of mitral valve dysfunction. The authors would like to highlight this multisystem involvement and the presence of a complex overlap of systemic features. PMID:22767536

  12. Odor Enrichment Sculpts the Abundance of Olfactory Bulb Mitral Cells

    PubMed Central

    Johnson, Melissa Cavallin; Biju, K.C.; Hoffman, Joshua; Fadool, Debra Ann

    2013-01-01

    Mitral cells are the primary output cell from the olfactory bulb conveying olfactory sensory information to higher cortical areas. Gene-targeted deletion of the Shaker potassium channel Kv1.3 alters voltage-dependence and inactivation kinetics of mitral cell current properties, which contribute to the “Super-smeller” phenotype observed in Kv1.3-null mice. The goal of the current study was to determine if morphology and density are influenced by mitral cell excitability, olfactory environment, and stage of development. Wildtype (WT) and Kv1.3-null (KO) mice were exposed to a single odorant (peppermint or citralva) for 30 days. Under unstimulated conditions, postnatal day 20 KO mice had more mitral cells than their WT counterparts, but no difference in cell size. Odor-enrichment with peppermint, an olfactory and trigeminal stimulus, decreased the number of mitral cells in three month and one year old mice of both genotypes. Mitral cell density was most sensitive to odor-stimulation in three month WT mice. Enrichment at the same age with citralva, a purely olfactory stimulus, decreased cell density regardless of genotype. There were no significant changes in cell body shape in response to citralva exposure, but the cell area was greater in WT mice and selectively greater in the ventral region of the OB in KO mice. This suggests that trigeminal or olfactory stimulation may modify mitral cell area and density while not impacting cell body shape. Mitral cell density can therefore be modulated by the voltage and sensory environment to alter information processing or olfactory perception. PMID:23485739

  13. Catheter interventions for mitral stenosis in children: results and perspectives.

    PubMed

    Saxena, Anita

    2015-04-01

    Stenosis of the mitral valve most often occurs as a result of chronic rheumatic heart disease, causing thickening and fibrosis of the mitral valve apparatus. Rheumatic heart disease continues to be a major public health problem in several developing countries and mitral stenosis is also common in these regions. According to the reports from India and Africa, the disease tends to follow a rapidly progressive course in children. The treatment of choice is balloon dilatation of the mitral valve. Echocardiography is indispensable for this procedure. Before planning the procedure, it is essential to assess the suitability of balloon dilatation. Echocardiography performed during the procedure helps to decide whether the size of the balloon needs to be increased in case of inadequate relief of stenosis. Most published series have reported an immediate success rate of over 90% with balloon dilatation in children and young adults. With an increase in mitral valve area and improvement in functional class, the left atrial pressure and the transmitral gradients fall. These gratifying results are also reported from very young children of less than 12 years of age. It is recommended to start with a smaller balloon size and increase its size in a stepwise fashion to minimize complications. The complications, seen in about 1% to 2% of cases, include development of significant mitral regurgitation and hemopericardium, secondary to cardiac chamber perforation. The long-term results indicate slightly higher restenosis rates in children than in adults. Most children with restenosis can undergo successful repeat dilatation. PMID:25870344

  14. 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.

  15. Mitral valve dysfunction and repair following orthotopic heart transplantation: a case report.

    PubMed

    Wigfield, C H; Lewis, A; Parry, G; Dark, J H

    2008-06-01

    Mitral valve dysfunction after orthotopic heart transplantation may cause symptoms refractory to medical therapy. In this report, we present a patient who underwent mitral annuloplasty for severe symptomatic mitral valve insufficiency 9 years after heart transplantation, and we critically appraise the literature available for mitral valve dysfunction in this setting. Mitral valve repair, when feasible, should be considered for mitral insufficiency after transplantation to improve functional status and reduce the risk of retransplantation--this is particularly prudent in view of chronic donor shortage. PMID:18589200

  16. Suture Forces in Undersized Mitral Annuloplasty: Novel Device and Measurements

    PubMed Central

    Siefert, Andrew; Pierce, Eric; Lee, Madonna; Jensen, Morten; Aoki, Chikashi; Takebayashi, Satoshi; Gorman, Robert; Gorman, Joseph; Yoganathan, Ajit

    2014-01-01

    Purpose: Demonstrate the first use of a novel technology for quantifying suture forces on annuloplasty rings to better understand the mechanisms of ring dehiscence. Description: Force transducers were developed, attached to a size 24 Physio™ ring, and implanted in the mitral annulus of an ovine animal. Ring suture forces were measured after implantation and for cardiac cycles reaching peak left ventricular pressures (LVP) of 100, 125, and 150 mmHg. Evaluation: After implanting the undersized ring to the flaccid annulus, the mean suture force was 2.0±0.6 N. During cyclic contraction, anterior ring suture forces were greater than posterior ring suture forces at peak LVPs of 100 mmHg (4.9±2.0 N vs. 2.1±1.1 N), 125 mmHg (5.4±2.3 N vs. 2.3±1.2 N), and 150 mmHg (5.7±2.4 N vs. 2.4±1.1 N). The largest force was 7.4 N at 150 mmHg. Conclusions: Preliminary results demonstrate trends in annuloplasty suture forces and their variation with location and LVP. Future studies will significantly contribute to clinical knowledge by elucidating the mechanisms of ring dehiscence while improving annuloplasty ring design and surgical repair techniques. PMID:24996707

  17. Management-Oriented Classification of Mitral Valve Regurgitation

    PubMed Central

    El Oakley, Reida; Shah, Aijaz

    2011-01-01

    Mitral regurgitation (MR) has previously been classified into rheumatic, primary, and secondary MR according to the underlying disease process. Carpentier's/Duran functional classifications are apt in describing the mechanism(s) of MR. Modern management of MR, however, depends primarily on the severity of MR, status of the left ventricular function, and the presence or absence of symptoms, hence the need for a management-oriented classification of MR. In this paper we describe a classification of MR into 4 phases according to LV function: phase I = MR with normal left ventricle, phase II = MR with normal ejection fraction (EF) and indirect signs of LV dysfunction such as pulmonary hypertension and/or recent onset atrial fibrillation, phase III = EF ≥ 30%–< 50% and/or mild to moderate LV dilatation (ESID 40–54 mm), and phase IV = EF < 30% and/or severe LV dilatation (ESDID ≥ 55 mm). Each phase is further subdivided into three stages: stage “A” with an effective regurgitant orifice (ERO) < 20 mm, stage “B” with an ERO = 20–39 mm, and stage “C” with an ERO ≥ 40 mm. Evidence-based indications and outcome of intervention for MR will also be discussed. PMID:22347660

  18. [Innervation of the intervertebral disc].

    PubMed

    García-Cosamalón, José; Fernández-Fernández, Javier; González-Martínez, Emilio; Ibáñez-Plágaro, Javier; Robla Costales, Javier; Martínez-Madrigal, Milton; López Muñíz, Alfonso; del Valle, Miguel Enrique; Vega, José Antonio

    2013-01-01

    Until very recently, intervertebral disc innervation was a subject of considerable debate. Nowadays, the introduction of inmunohistochemical techniques associated to specific antibodies and studies with retrograde tracers in nerves have allowed greater understanding of disc innervation in physiological and pathological conditions and also endings characteristics and their patterns of distribution in both situations. The existing controversies regarding structural basis of discogenic pain, have raised the interest of knowing the influence of innervation in back pain from discal origin and its characteristics. Today, we know that pathologic neoinnervation accompanying radial fissures is an important factor in the genesis of discogenic pain; within a complex mechanism in which other neurobiomechemical, inflammatory and biomechanical factors are involved. PMID:23582224

  19. Reappraisal of the ratio of disc to macula/disc diameter in optic nerve hypoplasia.

    PubMed Central

    Zeki, S M; Dudgeon, J; Dutton, G N

    1991-01-01

    The ratio of disc to macula/disc diameter is characteristically increased in eyes with optic nerve hypoplasia. We present the largest reported series of patients with a definitive diagnosis of optic nerve hypoplasia for whom this ratio has been determined. All measurements were made by an independent masked observer. Our results are in accordance with previous reports. A ratio of 2.94 provides a one-tailed upper population limit of 95%. An attempt has been made to correlate optic disc size and visual acuity. In 75% of bilateral cases the eye with the relatively smaller optic disc was found to have a better Snellen visual acuity than the fellow eye. This suggests that additional pathogenic mechanism(s) may have determined the eventual visual outcome in such eyes. Such mechanisms include macular hypoplasia, high refractive error, refractive amblyopia, central scotoma, and optic atrophy. Images PMID:1911656

  20. The Predictive Value of Mitral Leaflet Motion and Thickness Index Scores on Early Restenosis after Mitral Balloon Valvuloplasty

    PubMed Central

    Akin, Mustafa; Sagcan, Abdi; Nalbantgil, Sanem; Ozerkan, Filiz; Akilli, Azem; Yavuzgil, Oguz; Zoghi, Mehdi

    2004-01-01

    The purpose of this study was to investigate whether there is any association between mitral leaflet motion (LMI) and leaflet thickness index (LTI) scores and the rate of restenosis 3 months after successful mitral balloon valvuloplasty. The study population consisted of 46 patients with symptomatic rheumatic mitral stenosis who underwent balloon valvuloplasty (37 women, 9 men; mean age, 36 ± 9 years). Two-dimensional and Doppler echocardiography were performed in all patients on the day before, immediately after, and 3 months after valvuloplasty. The severity of restriction of leaflet motion and the severity of leaflet thickening were classified into grades of mild (a score of 0), moderate (a score of 1), and severe (a score of 2). Subvalvular disease and commissural involvement were homogeneous in all patients. Before and immediately after mitral balloon valvuloplasty, there were no significant differences in mitral valve area among the groups with different LMI and LTI scores. However, at 3 months after valvuloplasty, reduction in mitral valve area was more significant in patients who had higher pre-procedural LMI and LTI scores (P < 0.05). The rates of early restenosis were 0 with a total score of 0, 14.2% with a total score of 1–2, and 32% with a total score of 3. In conclusion, quantitative assessment of LMI and LTI scores by 2-dimensional echocardiography may be helpful in predicting early restenosis after mitral balloon valvuloplasty. Early reduction in mitral valve area is significant in patients who have higher total LMI and LTI scores. PMID:15562845

  1. Metallurgical evaluation of a failed LP turbine disc. Final report

    SciTech Connect

    Burghard, H.C. Jr.

    1982-12-01

    A metallurgical evaluation of a burst disc from the LP turbine at the Yankee Rowe nuclear generating station was performed. The turbine failure incident involves catastrophic rupture of both No. 1 discs during a start-up. The objectives of the evaluation were to characterize the disc materials and identify the cacking mechanism and other metallurgical factors involved in the failure. Metallographic and fractographic examinations of one segment of the No. generator-end disc were performed. The mechanical properties and composition of the disc segment were also determined. The investigation established that the radial fracture in the disc segment initiated at a service-induced crack and was of a generally brittle character. Also, numerous subcritical cracks were observed in the bore surface.

  2. The Application of Fiber-Reinforced Materials in Disc Repair

    PubMed Central

    Pei, Bao-Qing; Li, Hui; Zhu, Gang; Li, De-Yu; Fan, Yu-Bo; Wu, Shu-Qin

    2013-01-01

    The intervertebral disc degeneration and injury are the most common spinal diseases with tremendous financial and social implications. Regenerative therapies for disc repair are promising treatments. Fiber-reinforced materials (FRMs) are a kind of composites by embedding the fibers into the matrix materials. FRMs can maintain the original properties of the matrix and enhance the mechanical properties. By now, there are still some problems for disc repair such as the unsatisfied static strength and dynamic properties for disc implants. The application of FRMs may resolve these problems to some extent. In this review, six parts such as background of FRMs in tissue repair, the comparison of mechanical properties between natural disc and some typical FRMs, the repair standard and FRMs applications in disc repair, and the possible research directions for FRMs' in the future are stated. PMID:24383057

  3. Precision diagnostic disc injections.

    PubMed

    Fortin, J D

    2000-07-01

    Spinal pain is an important public health problem affecting the population indiscriminately. The structures responsible for pain in the spine include the vertebrae, intervertebral discs, spinal cord, nerve roots, facet joints, ligaments, muscles, atlanto-occipital joints, atlanto-axial joints, and sacroiliac joints. Even though disc herniation, facet joints, strained muscles, and torn ligaments have been attributed to be the cause of most spinal pain, either in the neck and upper extremities, upper and mid back, or low back and lower extremities, disorders of the disc other than disc herniation have been implicated more frequently than any other disorders. Once stifled by misinformation, discography now has applications in a number of clinical settings. While cervical and lumbar discography is well studied and well known, thoracic discography is in its nascent stages of clinical application. The value of discography lies in its ability to produce pain and thereby identify a "pain generator." This allows treatment to be based on the specific cause of pain. The three primary components of diagnostic disc injection are: provocation/analgesia, discometry, and nucleography. Despite the recent exponential growth of noninvasive spinal technology, diagnostic disc injection remains the sole direct method for definitively determining whether a disc is a physiological pain generator. It is clear that discography is a safe and powerful complement to the overall clinical context. PMID:16906185

  4. Percutaneous laser disc decompression.

    PubMed

    Choy, D S

    1995-06-01

    Herniated disc disease has an incidence of 1.7% in the U.S. Heretofore, open operative procedures were the rule for this condition when conservative measures were ineffective. Choy and Ascher introduced this new technique in February 1986 using a Nd:YAG laser introduced into the disc through an optical fiber in a needle. Percutaneous laser disc decompression is based on the principle that in an enclosed hydraulic space, such as an intact disc, a small reduction in volume is associated with a disproportionate fall in pressure. In the disc, this partial vacuum causes the herniated portion to move away from the nerve root back toward the center of the disc. This technique has been taught worldwide and is being performed in most of Europe, Japan, the United States, and Korea. In this special issue devoted to percutaneous laser disc decompression (PLDD), we will set forth the basic science of PLDD, patient selection, use of the holmium:YAG, and the Nd:YAG lasers, operative technique, and results. PMID:10150634

  5. Clinical experience in cell-based therapeutics: disc chondrocyte transplantation A treatment for degenerated or damaged intervertebral disc.

    PubMed

    Meisel, Hans Jörg; Siodla, Vilma; Ganey, Timothy; Minkus, Yvonne; Hutton, William C; Alasevic, Olivera J

    2007-02-01

    Disc herniation treated by discectomy results in a significant loss of nucleus material and disc height. Biological restoration through the use of autologous disc chondrocyte transplantation offers a potential to achieve functional integration of disc metabolism and mechanics. Chondrocytes that have been removed from damaged cartilaginous tissues maintain a capacity to proliferate, produce and secrete matrix components and respond to physical stimuli such as dynamic loading. Nucleus regeneration using autologous cultured disc-derived chondrocytes (ADCT) has been demonstrated in a canine model and in clinical pilot studies. In 2002 a prospective, controlled, randomised, multi-center study, EuroDISC, comparing safety and efficacy of autologous disc chondrocyte transplant, chondrotransplant DISC, plus discectomy (ADCT), with discectomy alone was initiated. A dog model was used to investigate the hypothesis that autologous disc chondrocytes can be used to repair damaged intervertebral disc. Disc chondrocytes were harvested and expanded in culture under controlled and defined conditions, returned to the same animals from which they had been sampled (autologous transplantation) via percutaneous delivery. The animals were analyzed at specific times after transplantation by several methods to examine whether disc chondrocytes integrated with the surrounding tissue, produced the appropriate intervertebral disc extracellular matrix, and might provide a formative solution to disc repair. The clinical goals of the EuroDISC study, were to provide long-term pain relief, maintain disc height and prevent adjacent segment disease. Interim analysis was performed after 2 years; Oswestry (low back pain/disability), Quebec Back-Pain Disability Scale, as well as Prolo and VAS score were used for the evaluation. Disc height was assessed by MRI. In the context of degenerative changes in an injury model: () autologous disc chondrocytes were expended in culture and returned to the disc by a

  6. Effect of intervertebral disc degeneration on disc cell viability: a numerical investigation.

    PubMed

    Galbusera, Fabio; Mietsch, Antje; Schmidt, Hendrik; Wilke, Hans-Joachim; Neidlinger-Wilke, Cornelia

    2013-01-01

    Degeneration of the intervertebral disc may be initiated and supported by impairment of the nutrition processes of the disc cells. The effects of degenerative changes on cell nutrition are, however, only partially understood. In this work, a finite volume model was used to investigate the effect of endplate calcification, water loss, reduction of disc height and cyclic mechanical loading on the sustainability of the disc cell population. Oxygen, lactate and glucose diffusion, production and consumption were modelled with non-linear coupled partial differential equations. Oxygen and glucose consumption and lactate production were expressed as a function of local oxygen concentration, pH and cell density. The cell viability criteria were based on local glucose concentration and pH. Considering a disc with normal water content, cell death was initiated in the centre of the nucleus for oxygen, glucose, and lactate diffusivities in the cartilaginous endplate below 20% of the physiological values. The initial cell population could not be sustained even in the non-calcified endplates when a reduction of diffusion inside the disc due to water loss was modelled. Alterations in the disc shape such as height loss, which shortens the transport route between the nutrient sources and the cells, and cyclic mechanical loads, could enhance cell nutrition processes. PMID:21970697

  7. 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. PMID:26183963

  8. 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

  9. Discharge patterning in rat olfactory bulb mitral cells in vivo

    PubMed Central

    Leng, Gareth; Hashimoto, Hirofumi; Tsuji, Chiharu; Sabatier, Nancy; Ludwig, Mike

    2014-01-01

    Abstract Here we present a detailed statistical analysis of the discharge characteristics of mitral cells of the main olfactory bulb of urethane‐anesthetized rats. Neurons were recorded from the mitral cell layer, and antidromically identified by stimuli applied to the lateral olfactory tract. All mitral cells displayed repeated, prolonged bursts of action potentials typically lasting >100 sec and separated by similarly long intervals; about half were completely silent between bursts. No such bursting was observed in nonmitral cells recorded in close proximity to mitral cells. Bursts were asynchronous among even adjacent mitral cells. The intraburst activity of most mitral cells showed strong entrainment to the spontaneous respiratory rhythm; similar entrainment was seen in some, but not all nonmitral cells. All mitral cells displayed a peak of excitability at ~25 msec after spikes, as reflected by a peak in the interspike interval distribution and in the corresponding hazard function. About half also showed a peak at about 6 msec, reflecting the common occurrence of doublet spikes. Nonmitral cells showed no such doublet spikes. Bursts typically increased in intensity over the first 20–30 sec of a burst, during which time doublets were rare or absent. After 20–30 sec (in cells that exhibited doublets), doublets occurred frequently for as long as the burst persisted, in trains of up to 10 doublets. The last doublet was followed by an extended relative refractory period the duration of which was independent of train length. In cells that were excited by application of a particular odor, responsiveness was apparently greater during silent periods between bursts than during bursts. Conversely in cells that were inhibited by a particular odor, responsiveness was only apparent when cells were active. Extensive raw (event timing) data from the cells, together with details of those analyses, are provided as supplementary material, freely available for secondary use

  10. 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

    2015-09-01

    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. PMID:26258302

  11. Discharge patterning in rat olfactory bulb mitral cells in vivo.

    PubMed

    Leng, Gareth; Hashimoto, Hirofumi; Tsuji, Chiharu; Sabatier, Nancy; Ludwig, Mike

    2014-10-01

    Here we present a detailed statistical analysis of the discharge characteristics of mitral cells of the main olfactory bulb of urethane-anesthetized rats. Neurons were recorded from the mitral cell layer, and antidromically identified by stimuli applied to the lateral olfactory tract. All mitral cells displayed repeated, prolonged bursts of action potentials typically lasting >100 sec and separated by similarly long intervals; about half were completely silent between bursts. No such bursting was observed in nonmitral cells recorded in close proximity to mitral cells. Bursts were asynchronous among even adjacent mitral cells. The intraburst activity of most mitral cells showed strong entrainment to the spontaneous respiratory rhythm; similar entrainment was seen in some, but not all nonmitral cells. All mitral cells displayed a peak of excitability at ~25 msec after spikes, as reflected by a peak in the interspike interval distribution and in the corresponding hazard function. About half also showed a peak at about 6 msec, reflecting the common occurrence of doublet spikes. Nonmitral cells showed no such doublet spikes. Bursts typically increased in intensity over the first 20-30 sec of a burst, during which time doublets were rare or absent. After 20-30 sec (in cells that exhibited doublets), doublets occurred frequently for as long as the burst persisted, in trains of up to 10 doublets. The last doublet was followed by an extended relative refractory period the duration of which was independent of train length. In cells that were excited by application of a particular odor, responsiveness was apparently greater during silent periods between bursts than during bursts. Conversely in cells that were inhibited by a particular odor, responsiveness was only apparent when cells were active. Extensive raw (event timing) data from the cells, together with details of those analyses, are provided as supplementary material, freely available for secondary use by others. PMID

  12. Herniated Lumbar Disc

    MedlinePlus

    ... 50. A herniated lumbar disc may also cause back pain, although back pain alone (without leg pain) can have many causes ... 90% success); surgery is less effective in relieving back pain. Nonsurgical treatment Your doctor may prescribe nonsurgical treatments ...

  13. Construction Strategy and Progress of Whole Intervertebral Disc Tissue Engineering.

    PubMed

    Yang, Qiang; Xu, Hai-Wei; Hurday, Sookesh; Xu, Bao-Shan

    2016-02-01

    Degenerative disc disease (DDD) is the major cause of low back pain, which usually leads to work absenteeism, medical visits and hospitalization. Because the current conservative procedures and surgical approaches to treatment of DDD only aim to relieve the symptoms of disease but not to regenerate the diseased disc, their long-term efficiency is limited. With the rapid developments in medical science, tissue engineering techniques have progressed markedly in recent years, providing a novel regenerative strategy for managing intervertebral disc disease. However, there are as yet no ideal methods for constructing tissue-engineered intervertebral discs. This paper reviews published reports pertaining to intervertebral disc tissue engineering and summarizes data concerning the seed cells and scaffold materials for tissue-engineered intervertebral discs, construction of tissue-engineered whole intervertebral discs, relevant animal experiments and effects of mechanics on the construction of tissue-engineered intervertebral disc and outlines the existing problems and future directions. Although the perfect regenerative strategy for treating DDD has not yet been developed, great progress has been achieved in the construction of tissue-engineered intervertebral discs. It is believed that ongoing research on intervertebral disc tissue engineering will result in revolutionary progress in the treatment of DDD. PMID:27028376

  14. Implantation of a new mitral ring, adjustable during follow-up: a simplified technique

    PubMed Central

    Caradonna, Eugenio; Testa, Nicola; De Filippo, Carlo Maria; Calvo, Eugenio; Di Giannuario, Giovanna; Spatuzza, Paola; Rossi, Marco; Alessandrini, Francesco

    2012-01-01

    Mitral valve repair for ischaemic mitral incompetence has a 10% rate of failure at ten year follow-up. Progressive annular dilation could play an important role. We have implanted the enCorSQTM mitral valve repair system. This system can be downsized during follow-up with the appropriate activation via the lead passed through the left atrium suture line, in order to restore mitral leaflet coaptation. PMID:22761123

  15. Implantation of a new mitral ring, adjustable during follow-up: a simplified technique.

    PubMed

    Caradonna, Eugenio; Testa, Nicola; De Filippo, Carlo Maria; Calvo, Eugenio; Di Giannuario, Giovanna; Spatuzza, Paola; Rossi, Marco; Alessandrini, Francesco

    2012-10-01

    Mitral valve repair for ischaemic mitral incompetence has a 10% rate of failure at ten year follow-up. Progressive annular dilation could play an important role. We have implanted the enCor(SQ)(TM) mitral valve repair system. This system can be downsized during follow-up with the appropriate activation via the lead passed through the left atrium suture line, in order to restore mitral leaflet coaptation. PMID:22761123

  16. Myxomatous degeneration of mitral valve. M-mode and two dimensional echocardiographic findings.

    PubMed Central

    Chun, P K; Sheehan, M W

    1982-01-01

    This report presents a patient with an unusual clinical course associated with a mitral "mass" recorded by M-mode and cross-sectional echocardiography. The "mass" was confirmed at operation to be redundant myxomatous mitral valve leaflets. The problem of echocardiographic resolution in the setting of mitral valve prolapse and of the differential diagnosis of mitral mass is discussed in detail. Images PMID:7066125

  17. Transaortic aortomitral junction reconstruction and mitral valve leaflet repair for recurrent endocarditis.

    PubMed

    Chiu, Peter; Allen, Jeremiah G; Woo, Y Joseph

    2015-03-01

    Transaortic interventions on the mitral valve are rarely performed, but offer advantages over traditional approaches in certain circumstances, including either extensive involvement of the aortomitral junction with endocarditis or the patient requiring reoperation for aortic and mitral disease. Herein is presented a case of recurrent endocarditis involving aortomitral continuity, reconstructed using a transaortic mitral valve repair and reconstruction of the aortic and mitral annuli with a pericardial patch, followed by aortic root replacement. PMID:26204680

  18. 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

  19. Herniated lumbar disc

    PubMed Central

    2011-01-01

    Introduction Herniated lumbar disc is a displacement of disc material (nucleus pulposus or annulus fibrosis) beyond the intervertebral disc space. The highest prevalence is among people aged 30 to 50 years, with a male to female ratio of 2:1. There is little evidence to suggest that drug treatments are effective in treating herniated disc. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of drug treatments, non-drug treatments, and surgery for herniated lumbar disc? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 37 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: acupuncture, advice to stay active, analgesics, antidepressants, bed rest, corticosteroids (epidural injections), cytokine inhibitors (infliximab), discectomy (automated percutaneous, laser, microdiscectomy, standard), exercise therapy, heat, ice, massage, muscle relaxants, non-steroidal anti-inflammatory drugs (NSAIDs), percutaneous disc decompression, spinal manipulation, and traction. PMID:21711958

  20. [Fibrinolytic therapy in thrombosis of a mitral valve prosthesis].

    PubMed

    Viedt, C; Mereles, D; Kübler, W; Kreuzer, J

    2000-08-01

    A 48-year-old woman presented with progressive dyspnea due to thrombosis of a mitral valve prosthesis. The patient had undergone mitral valve replacement (St. Jude Medical) six years prior to admission because of mitral stenosis (Class III); three years later the prosthesis had to be replaced (St. Jude Medical) because of valve thrombosis. At admission, transesophageal echocardiography showed a thrombus on the atrial side of the fixed valve leaflet and a thrombus (2.4 x 1.6 cm) floating from the left atrial roof. Because of the previous thoracotomies, thrombolysis was initiated despite the mobile thrombus with the attendant risk of embolization. Urokinase was infused in a dose to maintain the fibrinogen level around 100 mg/dl. After 24 h, the mean pressure gradient across the prosthetic mitral valve (measured by doppler echocardiography) had decreased from 23 to 11 mmHg. After 13 days of this modified thrombolytic regimen, the clinical symptoms of the patient had resolved and echocardiography showed a normal function of the prosthetic mitral valve without evidence of residual thrombosis. This patient demonstrates that prolonged cautious thrombolysis can be effective for the treatment of prosthetic valve thrombosis in hemodynamically moderately compromised patients. PMID:11013975

  1. Percutaneous and off-pump treatments for functional mitral regurgitation.

    PubMed

    Fukamachi, Kiyotaka

    2008-01-01

    A new era in the treatment of functional mitral regurgitation is emerging with new devices that can be placed percutaneously or minimally invasively without cardiopulmonary bypass. These devices are categorized into three groups: annuloplasty, edge-to-edge repair, and ventricular reshaping. Percutaneous annuloplasty devices, implanted via the coronary sinus, mimic surgical annuloplasty by reducing the mitral annular anterior-posterior (or septal-lateral) dimension. Several devices, such as the PTMA, CARILLON, Monarch, and PS3 systems, are in clinical trials. Percutaneous edge-to-edge repair devices mimic the surgical Alfieri edge-to-edge repair technique, creating a double-orifice mitral valve; of these, MitraClip is in clinical trials. Ventricular reshaping devices treat both mitral annular dilatation and papillary muscle displacement (and thus leaflet tethering). The surgical Coapsys device is currently in clinical trials, and its percutaneous "interventional" version, iCoapsys, is being prepared for a clinical trial. Numerous issues need to be addressed before these devices can become standard therapies for functional mitral regurgitation. Device safety and efficacy must be demonstrated in carefully designed clinical trials with the goal of achieving outcomes equal to or better than those of surgical repair. PMID:18414987

  2. 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. PMID:25440616

  3. Chemical derivatization of compact disc polycarbonate surfaces for SNPs detection.

    PubMed

    Bañuls, María-José; García-Piñón, Francisco; Puchades, Rosa; Maquieira, Angel

    2008-03-01

    Compact discs have been proposed as an efficient analytical platform, with potential to develop high-throughput affinity assays for genomics, proteomics, clinics, and health monitoring. Chemical derivatization of CD surfaces is one of the keys to developing highly efficient microarraying-based assays on discs. Approaches for mild chemical modification of polycarbonate (PC) disc surface based on nitration, reduction, and chloromethylation reactions have been developed. Derivatized surfaces as amino and thiol are obtained for PC, maintaining unchanged the mechanical and optical properties of the discs. Studies of covalent attachment of oligonucleotide probes (5' Cy5-labeled, 3' NH 2-ended) on the modified surfaces have been performed to develop microarraying assays based on hybridization of cDNA strands and single nucleotide polymorphism discrimination (SNPs). A demonstration of the applicability to the compact disc audio/video technology for its use as analytical system is performed, including the employment of a commercial CD player to read the results on disc. PMID:18254580

  4. 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

  5. Combined aortic and mitral valve replacement in an adult with Scheie's disease.

    PubMed

    Butman, S M; Karl, L; Copeland, J G

    1989-07-01

    Mitral, aortic, and coronary arterial disease have been described in the various mucopolysaccharidoses. We report the first successful combined aortic and mitral valve replacement in an adult female patient with severe aortic and mitral stenosis due to Scheie's syndrome, a mucopolysaccharide storage disease. Both annulae were of sufficient integrity for good prosthetic placement, and the patient had an uneventful postoperative recovery. PMID:2500310

  6. Recurrent infarctions due to a dome-shaped pannus above the mitral valve prosthesis

    PubMed Central

    Inoue, Yoshito; Suzuki, Satoru

    2016-01-01

    This report describes a unique case of a 56-year-old female who suffered from recurrent stroke after double mechanical valve replacement. During the four years after the surgery, she remained in normal sinus rhythm, received adequate anticoagulation therapy, and no apparent left atrial thrombus was detected. She underwent redo surgery to prevent further stroke after fourth instance of cerebral infarction. Intraoperative findings revealed a ‘dome-shaped’ pannus formation covering the sewing ring of the mitral prosthesis circumferentially, probably leading to clot formation and repeated infarctions. She has been stroke free for three years after pannus resection. PMID:26904241

  7. 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.

  8. Mitral valve apparatus: echocardiographic features predicting the outcome of percutaneous mitral balloon valvotomy

    PubMed Central

    Du Toit, R; Brice, EAW; Van Niekerk, JD; Doubell, AF

    2007-01-01

    Summary Objectives To evaluate the significance of involvement of subvalvular apparatus in the outcome of percutaneous mitral balloon valvotomy (PMBV) in patients with mitral stenosis (MS) and to determine the predictive value of chordal length compared with current echocardiographic scores. Methods Patients with significant MS were selected according to the Massachusetts General Hospital score (MGHS). Chordal lengths were assessed as additional markers of disease. Standard percutaneous valvotomies were performed. Valve area was assessed post-procedure with follow-up over one year. Results Thirty-nine patients were prospectively studied. Valve area increased from a mean (SD) 0.97 (0.26) cm2 to 1.52 (0.38) cm2 with procedural success in 31 (79.5%) patients. There was no correlation (r = 0.09) between the MGHS and final valve area (FV A). There was a positive correlation between anterior chordal length and FV A (r = 0.66; p = 0.01). An FV A ≥ 1.5 cm2 was associated with higher mean chordal lengths (p = 0.01). A positive correlation was seen between valve area pre-procedure and FV A (r = 0.61; p < 0.01). Conclusions The MGHS is valuable in the selection of patients for PMBV, but fails to separate selected patients into prognostic groups. Assessment of chordal length provides useful additional information, predicting the outcome of PMBV more accurately. Our data may support the earlier use of PMBV (asymptomatic patients). PMID:17612747

  9. Spiral shocks in a solar-size accretion disc

    NASA Astrophysics Data System (ADS)

    Harlaftis, E. T.; Steeghs, D.

    Accretion discs are fundamental in understanding astrophysical phenomena such as AGNs, novae outbursts and star formation. In interacting binaries, a compact star accretes matter from a donor star through an accretion disc. The outburst origin (disc or secondary star) and the mechanism for the angular momentum transport of the disc material (`viscosity') are still controversial subjects. The rarely-observed rise to outburst may hold the key to a better understanding. Imaging of the Balmer and He{I} emission lines of the dwarf nova IP Peg, during such a rise to outburst, shows a two-arm spiral pattern on the accretion disc around the white dwarf and provides the first convincing observational evidence for spiral waves in a stellar accretion disc (Steeghs, Harlaftis, Horne, 1997, Nature, submitted). Recent observations during the recent November 1996 outburst (Harlaftis, Steeghs, Horne, Martin, ApJ, 1997, in preparation) also demonstrate spiral arms in high-ionization lines such as HeII and the Bowen fluorescence lines which suggests that the spiral pattern may provide an efficient mechanism for trasport of angular momentum out of the disc through spiral shocks. We discuss the origin and location of the spiral arms. The tidal interaction of the secondary star with the enlarged (0.6 Rodot) outburst disc can raise such spiral waves in the outer disc. Comparison and implications for theories of spiral galaxies and planet formation is briefly outlined.

  10. 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. PMID:27184152

  11. 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.

  12. Curious case of calciphylaxis leading to acute mitral regurgitation

    PubMed Central

    Gallimore, Grant Gardner; Curtis, Blair; Smith, Andria; Benca, Michael

    2014-01-01

    Calciphylaxis is uncommon and typically seen in patients with end-stage renal disease. It has been defined as a vasculopathic disorder characterised by cutaneous ischaemia and necrosis due to calcification, intimal fibroplasia and thrombosis of pannicular arterioles. We present the case of a 74-year-old woman with chronic kidney disease stage III who developed calciphylaxis leading to mitral valve calcification, chordae tendineae rupture and acute mitral regurgitation. Although an alternative explanation can typically be found for non-uraemic calciphylaxis, her evaluation did not reveal any usual non-uraemic causes including elevated calcium–phosphorus product, hyperparathyroidism, or evidence of connective tissue disease. Her wounds improved with sodium thiosulfate, pamidronate, penicillin and hyperbaric oxygen therapies but she ultimately decompensated with the onset of acute mitral regurgitation attributed to rupture of a previously calcified chordae tendineae. This case highlights an unusual case of calciphylaxis without clear precipitant as well as a novel manifestation of the disease. PMID:24789150

  13. 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

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

    PubMed

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

    2016-09-01

    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

  15. Intermediate mass black holes in AGN discs - I. Production and growth

    NASA Astrophysics Data System (ADS)

    McKernan, B.; Ford, K. E. S.; Lyra, W.; Perets, H. B.

    2012-09-01

    Here we propose a mechanism for efficiently growing intermediate mass black holes (IMBH) in discs around supermassive black holes. Stellar mass objects can efficiently agglomerate when facilitated by the gas disc. Stars, compact objects and binaries can migrate, accrete and merge within discs around supermassive black holes. While dynamical heating by cusp stars excites the velocity dispersion of nuclear cluster objects (NCOs) in the disc, gas in the disc damps NCO orbits. If gas damping dominates, NCOs remain in the disc with circularized orbits and large collision cross-sections. IMBH seeds can grow extremely rapidly by collisions with disc NCOs at low relative velocities, allowing for super-Eddington growth rates. Once an IMBH seed has cleared out its feeding zone of disc NCOs, growth of IMBH seeds can become dominated by gas accretion from the active galactic nucleus (AGN) disc. However, the IMBH can migrate in the disc and expand its feeding zone, permitting a super-Eddington accretion rate to continue. Growth of IMBH seeds via NCO collisions is enhanced by a pile-up of migrators. We highlight the remarkable parallel between the growth of IMBH in AGN discs with models of giant planet growth in protoplanetary discs. If an IMBH becomes massive enough it can open a gap in the AGN disc. IMBH migration in AGN discs may stall, allowing them to survive the end of the AGN phase and remain in galactic nuclei. Our proposed mechanisms should be more efficient at growing IMBH in AGN discs than the standard model of IMBH growth in stellar clusters. Dynamical heating of disc NCOs by cusp stars is transferred to the gas in an AGN disc helping to maintain the outer disc against gravitational instability. Model predictions, observational constraints and implications are discussed in a companion paper (Paper II).

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

    PubMed

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

    2015-12-01

    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

  17. 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

  18. 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.

  19. New method of posterior scallop augmentation for ischemic mitral regurgitation.

    PubMed

    Aoki, Masakazu; Ito, Toshiaki

    2015-03-01

    We report a new method of posterior middle scallop (P2) augmentation for ischemic mitral regurgitation to achieve deep coaptation. First, P2 was divided straight at the center and partially detached from the annulus in a reverse T shape. A narrow pentagon-shaped section of pericardium was sutured to the divided P2 and annular defect. The tip of the pentagon was attached directly to the papillary muscle, thus creating a very large P2 scallop. A standard-sized ring was placed. We adopted this technique in 2 patients with advanced ischemic cardiomyopathy, and no mitral regurgitation was observed during a 1-year follow-up. PMID:25742844

  20. Subvalvular pannus and thrombosis in a mitral valve prosthesis.

    PubMed

    Kim, Gun Ha; Yang, Dong Hyun; Kang, Joon-Won; Kim, Dae-Hee; Jung, Sung-Ho; Lim, Tae-Hwan

    2016-01-01

    A 69-year-old female underwent cardiac CT to evaluate prosthetic valve (PHV) dysfunction detected on echocardiography. A CT coronal and en face views of the mitral annular plane showed a low-density, mass-like lesion on the left atrial side of the PHV and a high-density, plate-like lesion on the left ventricular side of PHV. A repeat of the mitral valve replacement was performed, and preoperative CT findings of both the thrombus on the left atrial side and pannus formation on the LV side were confirmed in the operative findings. PMID:26452593

  1. 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

  2. Surgery for congenital mitral valve disease in the first year of life.

    PubMed

    Uva, M S; Galletti, L; Gayet, F L; Piot, D; Serraf, A; Bruniaux, J; Comas, J; Roussin, R; Touchot, A; Binet, J P

    1995-01-01

    Between 1980 and 1993, 20 patients less than 1 year of age underwent operations for congenital mitral valve disease. Ten patients had congenital mitral incompetence and 10 had congenital mitral stenosis. Mean age was 6.6 +/- 3.4 months and mean weight was 5.6 +/- 1.5 kg. Atrioventricular canal defects, univentricular heart, class III/IV hypoplastic left heart syndrome, discordant atrioventricular and ventriculoarterial connections, and acquired mitral valve disease were excluded. Indications for operation were intractable heart failure or severe pulmonary hypertension, or both. Associated lesions, present in 90% of the patients, had been corrected by a previous operation in seven. In congenital mitral incompetence there was normal leaflet motion (n = 3), leaflet prolapse (n = 2), and restricted leaflet motion (n = 5). In congenital mitral stenosis anatomic abnormalities were parachute mitral valve (n = 4), typical mitral stenosis (n = 3), hammock mitral valve (n = 2), and supramitral ring (n = 1). Mitral valve repair was initially performed in 19 patients and valve replacement in one with hammock valve. Concurrent repair of associated lesions was performed in 12 patients. The operative mortality rate was zero. There were six early reoperations in five patients for mitral valve replacement (n = 4), a second repair (n = 1), and prosthetic valve thrombectomy (n = 1). One late death occurred 9 months after valve replacement. Late reoperations for mitral valve replacement (n = 2), aortic valve replacement (n = 1), mitral valve repair (n = 2), subaortic stenosis resection (n = 1), and second mitral valve replacement (n = 1) were performed in five patients. Actuarial freedom from reoperation is 58.0% +/- 11.3% (70% confidence limits 46.9% to 68.9%) at 7 years. After a mean follow-up of 67.6 +/- 42.8 months, 94% of living patients are in New York Heart Association class I. Doppler echocardiographic studies among the 13 patients with a native mitral valve show mitral

  3. A Mechanical model for flexible exercise bars to study the influence of the initial position of the bar on lumbar discs and muscles forces.

    PubMed

    Khalaf, Kinda; Abdollahi, Masoud; Nikkhoo, Mohammad; Hoviattalab, Maryam; Asghari, Mohsen; Ashouri, Sajad; Nikpour, Seyedhassan; Kahrizi, Sedighe; Parnianpour, Mohamad

    2015-08-01

    A single-degree-of-freedom model is considered for flexible exercise bars based on the lumped-element approach. By considering the side segment of a flexible bar as a cantilever beam with an equivalent mass at the free end, its free-vibration response, as well as the forced response under the excitation of the grip, are expressed parametrically. Experiments are performed on a particular flexible bar (FLEXI_BAR) in order to obtain numerical values for quantifying the model's parameters. The model is also computationally simulated to study the response of the flexible bar to various excitations. The results are imported into a multi-segment musculoskeletal software (AnyBody), where the effect of different initial hand positions on the lumbar disc and back muscle forces is investigated (including Longissimus, Iliocostalis, and Transversus) during up-down exercises. The results show that all intervertebral discs and muscles forces are more sensitive to the horizontal position of the bar as compared to its vertical position. PMID:26737150

  4. Structures induced by companions in galactic discs

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    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 by 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 (parameterized 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 (SFASI) 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 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 ILR to a radius close to, but inside, corotation.

  5. Effect of Transcatheter Mitral Annuloplasty With the Cardioband Device on 3-Dimensional Geometry of the Mitral Annulus.

    PubMed

    Arsalan, Mani; Agricola, Eustachio; Alfieri, Ottavio; Baldus, Stephan; Colombo, Antonio; Filardo, Giovanni; Hammerstingl, Christophe; Huntgeburth, Michael; Kreidel, Felix; Kuck, Karl-Heinz; LaCanna, Giovanni; Messika-Zeitoun, David; Maisano, Francesco; Nickenig, Georg; Pollock, Benjamin D; Roberts, Bradley J; Vahanian, Alec; Grayburn, Paul A

    2016-09-01

    This study was performed to assess the acute intraprocedural effects of transcatheter direct mitral annuloplasty using the Cardioband device on 3-dimensional (3D) anatomy of the mitral annulus. Of 45 patients with functional mitral regurgitation (MR) enrolled in a single arm, multicenter, prospective trial, 22 had complete pre- and post-implant 3D transesophageal echocardiography (TEE) images stored in native data format that allowed off-line 3D reconstruction. Images with the highest volume rate and best image quality were selected for analysis. Multiple measurements of annular geometry were compared from baseline to post-implant using paired t tests with Bonferroni correction to account for multiple comparisons. The device was successfully implanted in all patients, and MR was reduced to moderate in 2 patients, mild in 17 patients, and trace in 3 patients after final device cinching. Compared with preprocedural TEE, postprocedural TEE showed statistically significantly reductions in annular circumference (137 ± 15 vs 128 ± 17 mm; p = 0.042), intercommissural distance (42.4 ± 4.3 vs 38.6 ± 4.4 mm; p = 0.029), anteroposterior distance (40.0 ± 5.4 vs 37.0 ± 5.7 mm; p = 0.025), and aortic-mitral angle (117 ± 8° vs 112 ± 8°; p = 0.032). This study demonstrates that transcatheter direct mitral annuloplasty with the Cardioband device results in acute remodeling of the mitral annulus with successful reduction of functional MR. PMID:27389565

  6. The ProDisc artificial disc: insertion technique.

    PubMed

    Aryan, Henry E; Acosta, Frank L; Ames, Christopher P

    2005-10-01

    The ProDisc artificial lumbar disc was designed for use in treatment of degenerative lumbar disease. The disc is implanted using an anterior approach to the lumbar spine with the assistance of intraoperative fluoroscopy. A variety of insertion instruments guide the surgeon through this process. The disc is implanted via an anterior approach, generally retroperitoneally but on occasion transperitoneally. The different approaches and insertion technique are described in this article. PMID:16326288

  7. Lumbar disc replacement: preliminary results with ProDisc II after a minimum follow-up period of 1 year.

    PubMed

    Tropiano, Patrick; Huang, Russel C; Girardi, Federico P; Marnay, Thierry

    2003-08-01

    Total disc replacement has the potential to replace fusion as the gold standard surgical treatment of degenerative disc disease. Potential advantages of disc replacement over fusion include avoidance of pseudarthrosis, postoperative orthoses, and junctional degeneration. After observing satisfactory clinical results at 7-11 years' follow-up with the ProDisc first-generation implant, a second-generation prosthesis was designed. This study is a prospective analysis of the early results of total disc replacement with the ProDisc II total disc prosthesis. Fifty-three patients had single-level or multilevel disc replacement and were evaluated clinically and radiographically preoperatively and at mean 1.4-year follow-up. There were clinically and statistically significant improvements in back and leg pain Visual Analog Scale and Oswestry disability scores that were maintained at final follow-up. The clinical results of patients with single- and multilevel surgery were equivalent. Satisfactory results were achieved in 90% of patients who had previous lumbar surgery. Complications occurred in 9% of patients and included vertebral body fracture, transient radicular pain, implant malposition, and transient retrograde ejaculation. Three patients (6%) required reoperation to address complications. No mechanical failure of the implants or loosening was observed, and the prostheses retained motion. Randomized, prospective, long-term studies will be necessary to compare the effectiveness of arthrodesis with total disc replacement. PMID:12902952

  8. 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

  9. Perinatal Changes in Mitral and Aortic Valve Structure and Composition

    PubMed Central

    Stephens, Elizabeth H.; Post, Allison D.; Laucirica, Daniel R.; Grande-Allen, K. Jane

    2015-01-01

    At birth, the mechanical environment of valves changes radically as fetal shunts close and pulmonary and systemic vascular resistances change. Given that valves are reported to be mechanosensitive, we investigated remodeling induced by perinatal changes by examining compositional and structural differences of aortic and mitral valves (AVs, MVs) between 2-day-old and 3rd fetal trimester porcine valves using immunohistochemistry and Movat pentachrome staining. Aortic valve composition changed more with birth than the MV, consistent with a greater change in AV hemodynamics. At 2 days, AV demonstrated a trend of greater versican and elastin (P = 0.055), as well as greater hyaluronan turnover (hyaluronan receptor for endocytosis, P = 0.049) compared with the 3rd-trimester samples. The AVs also demonstrated decreases in proteins related to collagen synthesis and fibrillogenesis with birth, including procollagen I, prolyl 4-hydroxylase, biglycan (all P ≤ 0.005), and decorin (P = 0.059, trend). Both AVs and MVs demonstrated greater delineation between the leaflet layers in 2-day-old compared with 3rd-trimester samples, and AVs demonstrated greater saffron-staining collagen intensity, suggesting more mature collagen in 2-day-old compared with 3rd-trimester samples (each P < 0.05). The proportion of saffron-staining collagen also increased in AV with birth (P < 0.05). The compositional and structural changes that occur with birth, as noted in this study, likely are important to proper neonatal valve function. Furthermore, normal perinatal changes in hemodynamics often do not occur in congenital valve disease; the corresponding perinatal matrix maturation may also be lacking and could contribute to poor function of congenitally malformed valves. PMID:20536360

  10. Mitral valve disease in pregnancy: outcomes and management

    PubMed Central

    Tsiaras, Sarah; Poppas, Athena

    2009-01-01

    Young women may have asymptomatic mitral valve disease which becomes unmasked during the haemodynamic stress of pregnancy. Rheumatic mitral stenosis is the most common cardiac disease found in women during pregnancy. The typical increased volume and heart rate of pregnancy are not well tolerated in patients with more than mild stenosis. Maternal complications of atrial fibrillation and congestive heart failure can occur, and are increased in patients with poor functional class and severe pulmonary artery hypertension. Patients can be diagnosed by echocardiography and symptoms treated with beta-1 antagonists and cautious diuresis. Patients with heart failure unresponsive to treatment can undergo percutaneous balloon mitral valvuloplasty. Labour and delivery goals include reducing tachycardia by adequate pain control and minimized volume shifts. Mitral valve regurgitation, even when severe, is usually very well tolerated in pregnancy as the increase in volume is offset by a decrease in vascular resistance. On the other hand, patients with left ventricular dysfunction, moderate pulmonary hypertension or NYHA functional class III-IV are at increased risk for heart failure and arrhythmias. They may need cautious diuresis and limitations on physical activity during pregnancy, as well as invasive haemodynamic monitoring for labour and delivery. Vaginal delivery is preferred and caesarean section reserved for obstetric indications.

  11. Custodiol® HTK Cardioplegia Use in Robotic Mitral Valve

    PubMed Central

    Patel, Nirav; DeLaney, Ed; Turi, Gerard; Stapleton, Thomas

    2013-01-01

    Abstract: Robotic surgery is a growing subspecialty in cardiac surgery. Custodiol® HTK cardioplegia offers long-term myocardial protection, decreased metabolism, and eliminates multiple cardioplegia dosing. This article reviews the technique, strategy, and considerations for use of Custodiol® HTK for myocardial protection in robotic mitral valve surgery. PMID:23930386

  12. Intracardiac calipers for artificial chordae replacement in mitral valve repair.

    PubMed

    Doi, Atsuo; Iida, Hiroshi; Sunazawa, Toru

    2009-01-01

    Length adjustment of artificial chordae is crucial in the outcome of anterior mitral valve repair. Herein, a simple and reproducible method of artificial chordal replacement using polytetrafluoroethylene suture is described. With this technique, the length of the neo-chordae is easily decided and the knot can be tied surely without change in the length using only one instrument. PMID:19101333

  13. 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.

  14. The Chemistry of Optical Discs.

    ERIC Educational Resources Information Center

    Birkett, David

    2002-01-01

    Explains the chemistry used in compact discs (CD), digital versatile discs (DVD), and magneto-optical (MO) discs focusing on the steps of initial creation of the mold, the molding of the polycarbonate, the deposition of the reflective layers, the lacquering of the CDs, and the bonding of DVDs. (Contains 15 references.) (YDS)

  15. 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.

  16. 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…

  17. Learning Language on Disc.

    ERIC Educational Resources Information Center

    Desmarais, Norman

    1995-01-01

    Presents a comparison of two types of compact disc (CD-ROM) foreign language tutorials: (1) those made by publishers who favor an immersion approach; and (2) those made by publishers who use grammar-based approaches. Both types of CD-ROMs address various age groups, skill levels, and learning styles. (JMV)

  18. The DISC Quotient

    NASA Astrophysics Data System (ADS)

    Elliott, John R.; Baxter, Stephen

    2012-09-01

    D.I.S.C: Decipherment Impact of a Signal's Content. The authors present a numerical method to characterise the significance of the receipt of a complex and potentially decipherable signal from extraterrestrial intelligence (ETI). The purpose of the scale is to facilitate the public communication of work on any such claimed signal, as such work proceeds, and to assist in its discussion and interpretation. Building on a "position" paper rationale, this paper looks at the DISC quotient proposed and develops the algorithmic steps and comprising measures that form this post detection strategy for information dissemination, based on prior work on message detection, decipherment. As argued, we require a robust and incremental strategy, to disseminate timely, accurate and meaningful information, to the scientific community and the general public, in the event we receive an "alien" signal that displays decipherable information. This post-detection strategy is to serve as a stepwise algorithm for a logical approach to information extraction and a vehicle for sequential information dissemination, to manage societal impact. The "DISC Quotient", which is based on signal analysis processing stages, includes factors based on the signal's data quantity, structure, affinity to known human languages, and likely decipherment times. Comparisons with human and other phenomena are included as a guide to assessing likely societal impact. It is submitted that the development, refinement and implementation of DISC as an integral strategy, during the complex processes involved in post detection and decipherment, is essential if we wish to minimize disruption and optimize dissemination.

  19. 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)

  20. 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.

  1. Regional variations in the compressive properties of lumbar vertebral trabeculae. Effects of disc degeneration

    SciTech Connect

    Keller, T.S.; Hansson, T.H.; Abram, A.C.; Spengler, D.M.; Panjabi, M.M. )

    1989-09-01

    The compressive mechanical properties of human lumbar vertebral trabeculae were examined on the basis of anatomic origin, bone density, and intervertebral disc properties. Trabecular bone compressive strength and stiffness increased with increasing bone density, the latter proportional to strength and stiffness to the one-half power. Regional variations within each segment were found, the most prevalent differences occurring in regions of bone overlying the disc nucleus in comparison with bone overlying the disc anulus. For normal discs, the ratio of strength of bone overlying the disc nucleus to bone overlying the disc anulus was 1.25, decreasing to 1.0 for moderately degenerated discs. These results suggest that an interdependency of trabecular bone properties and intervertebral disc properties may exist.

  2. Lumbar Degenerative Disc Disease: Current and Future Concepts of Diagnosis and Management

    PubMed Central

    Taher, Fadi; Essig, David; Lebl, Darren R.; Hughes, Alexander P.; Sama, Andrew A.; Cammisa, Frank P.; Girardi, Federico P.

    2012-01-01

    Low back pain as a result of degenerative disc disease imparts a large socioeconomic impact on the health care system. Traditional concepts for treatment of lumbar disc degeneration have aimed at symptomatic relief by limiting motion in the lumbar spine, but novel treatment strategies involving stem cells, growth factors, and gene therapy have the theoretical potential to prevent, slow, or even reverse disc degeneration. Understanding the pathophysiological basis of disc degeneration is essential for the development of treatment strategies that target the underlying mechanisms of disc degeneration rather than the downstream symptom of pain. Such strategies ideally aim to induce disc regeneration or to replace the degenerated disc. However, at present, treatment options for degenerative disc disease remain suboptimal, and development and outcomes of novel treatment options currently have to be considered unpredictable. PMID:22567411

  3. A novel coaptation plate device for functional mitral regurgitation: an in vitro study.

    PubMed

    He, Zhaoming; Zhang, Kailiang; Gao, Bo

    2014-10-01

    A novel mitral valve repair device, coaptation plate (CP), was proposed to treat functional mitral regurgitation. The objective of this study was to test efficacy of the CP in an in vitro model of functional mitral regurgitation. Ten fresh porcine mitral valves were mounted in a left heart simulator, Mitral regurgitation was emulated by means of annular dilatation, and the asymmetrical or symmetrical papillary muscles (PM) displacement. A rigid and an elastic CPs were fabricated and mounted in the orifice of regurgitant mitral valves. Steady flow leakage in a hydrostatic condition and regurgitant volume in a pulsatile flow were measured before and after implantation of the CPs. The rigid and elastic CPs reduced mitral valve regurgitant volume fraction from 60.5 ± 11.4 to 35 ± 11.6 and 36.5 ± 9.9%, respectively, in the asymmetric PM displacement. Mitral regurgitation was much lower in the symmetric PM displacement than in the asymmetric PM displacement, and was not significantly reduced after implantation of either CP. In conclusion, both the rigid and elastic CPs are effective and have no difference in reduction of functional mitral regurgitation. The CP does not aggravate mitral valve coaptation and may be used as a preventive way. PMID:25015132

  4. Use of four MitraClip devices in a patient with ischemic cardiomyopathy and mitral regurgitation: "zipping by clipping".

    PubMed

    Kische, Stephan; Nienaber, Christoph; Ince, Hüseyin

    2012-11-15

    Severe mitral regurgitation (MR) as a consequence of underlying left ventricular dysfunction substantially contributes to morbidity and mortality. A variety of percutaneous treatment options for mitral valve repair have been developed; however, most of these techniques are still at an early stage of clinical evaluation. Today, percutaneous edge-to-edge mitral valve repair using the MitraClip® system is the only endovascular approach that demonstrated noninferiority when compared with standard surgical repair in a randomized trial. However, a considerable number of patients with functional MR will present with extensive annulus dilatation and minimal vertical leaflet coaptation that potentially preclude them from this beneficial technology for anatomical reasons. In this report, we portray a 72-year-old man presenting with end-stage systolic heart failure and severe functional MR as a consequence of long-standing coronary artery disease. Recently, his clinical course was complicated by intractable hemodynamic instability and recurrent pulmonary edema. High predicted mortality and progressive physical decay rendered this moribund patient a candidate for salvage percutaneous mitral valve repair. During the endovascular procedure, a central systolic coaptation gap of 7 mm proved to be too wide for adequate simultaneous grasping of both leaflets. Consideration was given to an alternative approach by means of our novel "zipping technique." Through the trans-septal route, medial to lateral approximation of the tethered leaflets was successfully achieved by intentional deployment of four MitraClip® devices. With the first in-human application of four mechanical implants, a profound reduction of MR grade has been accomplished by the creation of a lateral neo-orifice with apparent acute clinical success. However, it needs to be determined whether successful application of the zipping technique leads to sustained reverse ventricular remodeling and will translate into an

  5. Inter-lamellar shear resistance confers compressive stiffness in the intervertebral disc: An image-based modelling study on the bovine caudal disc.

    PubMed

    Adam, Clayton; Rouch, Philippe; Skalli, Wafa

    2015-12-16

    The intervertebral disc withstands large compressive loads (up to nine times bodyweight in humans) while providing flexibility to the spinal column. At a microstructural level, the outer sheath of the disc (the annulus fibrosus) comprises 12-20 annular layers of alternately crisscrossed collagen fibres embedded in a soft ground matrix. The centre of the disc (the nucleus pulposus) consists of a hydrated gel rich in proteoglycans. The disc is the largest avascular structure in the body and is of much interest biomechanically due to the high societal burden of disc degeneration and back pain. Although the disc has been well characterized at the whole joint scale, it is not clear how the disc tissue microstructure confers its overall mechanical properties. In particular, there have been conflicting reports regarding the level of attachment between adjacent lamellae in the annulus, and the importance of these interfaces to the overall integrity of the disc is unknown. We used a polarized light micrograph of the bovine tail disc in transverse cross-section to develop an image-based finite element model incorporating sliding and separation between layers of the annulus, and subjected the model to axial compressive loading. Validation experiments were also performed on four bovine caudal discs. Interlamellar shear resistance had a strong effect on disc compressive stiffness, with a 40% drop in stiffness when the interface shear resistance was changed from fully bonded to freely sliding. By contrast, interlamellar cohesion had no appreciable effect on overall disc mechanics. We conclude that shear resistance between lamellae confers disc mechanical resistance to compression, and degradation of the interlamellar interface structure may be a precursor to macroscopic disc degeneration. PMID:26549764

  6. 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. PMID:27008972

  7. [Bioprosthesis degeneration in the aortic and mitral valve position. Results and problems from the cardiosurgical viewpoint].

    PubMed

    Antretter, H; Cottogni, M; Falbesoner, C; Furtwängler, W; Mair, P; Falk, M; Hutter, J

    1993-01-01

    38 patients (20 men, 18 women) underwent reoperation between July 1989 to September 1992 because of degeneration of bioprosthetic valves implanted in aortic or/and mitral position. Retrospective analysis revealed a mean implantation time of 116.5 +/- 31.5 months for the bioprostheses (median 116). At reoperation 63.2% of them had a single valve replacement, 36.8% a more complex cardiac procedure (double or triple valve replacement, valve replacement and coronary bypass grafting). 50% (n = 9) of the reoperation cohort were symptomatic (NYHA III), 16 (42.1%) were serious symptomatic (NYHA IV). All deaths were NYHA IV preoperatively. Early mortality was 18.4% (n = 7). Mean age at the time of first operation was 51 +/- 10.7, mean age at reoperation was 60.5 +/- 10.6. There was a significantly longer aortic clamp time (AKT, p = 0.0005) and bypass time (BPT, p = 0.0000) compared to first operation, also a significantly longer BPT of the deads confronted with the survivors (p = 0.0075). Bioprosthetic valves in mitral position were significantly longer implanted (p = 0.0416) than in aortic position. But there was no difference in implantation time of commercially available Carpentier-Edwards- or Ionescu-Shiley grafts. At reoperation we changed more than 95% of the degenerated valves to mechanical devices--corresponding to international tendencies. We discuss the early tissue degeneration of bioprosthetic valves and their increasing problem during reoperation. PMID:8212714

  8. In vitro assessment of mitral valve function in cyclically pressurized porcine hearts.

    PubMed

    Vismara, Riccardo; Leopaldi, Alberto M; Piola, Marco; Asselta, Chiara; Lemma, Massimo; Antona, Carlo; Redaelli, Alberto; van de Vosse, Frans; Rutten, Marcel; Fiore, Gianfranco B

    2016-04-01

    Recent approaches to the in vitro experimental study of cardiac fluid mechanics involve the use of whole biological structures to investigate in the lab novel therapeutic approaches for the treatment of heart pathologies. To enhance reliability and repeatability, the influence of the actuation strategy of the experimental apparatuses on the biomechanics of biological structures needs to be assessed. Using echography and intracardiac high-speed imaging, we compared the mitral valve (MV) anatomo-functional features (coaptation areas/lengths, papillary muscles-valvular plane distances) in two passive-beating-heart mock loops with internal (IPML) or external (EPML) pressurization of the ventricular chamber. Both apparatuses showed fluid dynamic conditions that closely resembled the physiology. The MVs analyzed in the EPML presented coaptation areas and lengths that were systematically higher, and exhibited greater variability from early-to peak-systole, as compared to those in the IPML. Moreover, in the EPML, the MV leaflets exhibited a convexity with high curvature toward the atrium. With the IPML, MV coaptation lengths ranged similar to available clinical data and the papillary muscles-valve plane distances were more stable throughout systole. In conclusion, both the apparatuses allow for reproducing in vitro the left heart hemodynamics, in terms of flow rates and pressures, with proper mitral valve continence. Results suggest that the IPML is more suitable for replicating the physiological MV functioning, while the EPML may have more potential as a model for the study of MV pathologies. PMID:26908180

  9. Localisation and direction of mitral regurgitant flow in mitral orifice studied with combined use of ultrasonic pulsed Doppler technique and two dimensional echocardiography.

    PubMed Central

    Miyatake, K; Nimura, Y; Sakakibara, H; Kinoshita, N; Okamoto, M; Nagata, S; Kawazoe, K; Fujita, T

    1982-01-01

    Regurgitant flow was analysed in 40 cases of mitral regurgitation, using combined ultrasonic pulsed Doppler technique and two dimensional echocardiography. Abnormal Doppler signals indicative of mitral regurgitant flow were detected in reference to the two dimensional image of the long axis view of the heart and the short axis view at the level of the mitral orifice. The overall direction of regurgitant flow into the left atrium was clearly seen in 28 of 40 cases, and the localisation of regurgitant flow in the mitral orifice in 38 cases. In cases with mitral valve prolapse of the anterior leaflet or posterior leaflet the regurgitant flow was directed posteriorly or anteriorly, respectively. The prolapse occurred at the anterolateral commissure or posteromedial commissure and resulted in regurgitant flow located near the anterolateral commissure or posteromedial commissure of the mitral orifice, respectively. In cases with rheumatic mitral regurgitation the regurgitant flow is usually towards the central portion of the left atrium and is sited in the mid-part of the orifice. The Doppler findings were consistent with left ventriculography and surgical findings. The ultrasonic pulsed Doppler technique combined with two dimensional echocardiography is useful for non-invasive analysis and preoperative assessment of mitral regurgitation. Images PMID:7138708

  10. 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.

  11. The Origin and Evolution of Transition Discs: Successes, Problems, and Open Questions

    NASA Astrophysics Data System (ADS)

    Owen, James E.

    2016-02-01

    Transition discs are protoplanetary discs that show evidence for large holes or wide gaps (with widths comparable to their radii) in their dust component. These discs could be giving us clues about the disc destruction mechanism or hints about the location and time-scales for the formation of planets. However, at the moment there remain key gaps in our theoretical understanding. The vast majority of transition discs are accreting onto their central stars, indicating that-at least close to the star-dust has been depleted from the gas by a very large amount. In this review, we discuss evidence for two distinct populations of transition discs: mm-faint-those with low mm-fluxes, small holes (≲ 10 AU), and low accretion rates (~ 10-10 - 10-9 M⊙ yr-1) and mm-bright-discs with large mm-fluxes, large holes (≳ 20 AU), and high accretion rates ~ 10-8 M⊙ yr-1. MM-faint transition discs are consistent with what would naively be expected from a disc undergoing dispersal; however, mm-bright discs are not, and are likely to be rare and long-lived objects. We discuss the two commonly proposed mechanisms for creating transition discs: photoevaporation and planet-disc interactions, with a particular emphasis on how they would evolve in these models, comparing these predictions to the observed population. More theoretical work on explaining the lack of optically thick, non-accreting transition discs is required in both the photoevaporation and planetary hypothesis, before we can start to use transition discs to constrain models of planet formation. Finally, we suggest that the few discs with primordial looking spectral energy distribution, but serendipitously imaged showing large cavities in the mm (e.g. MWC758 and WSB 60) may represent a hidden population of associated objects. Characterising and understanding how these objects fit into the overall paradigm may allow us to unravel the mystery of transition discs.

  12. 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

  13. DISC1 Ser704Cys impacts thalamic-prefrontal connectivity.

    PubMed

    Liu, Bing; Fan, Lingzhong; Cui, Yue; Zhang, Xiaolong; Hou, Bing; Li, Yonghui; Qin, Wen; Wang, Dawei; Yu, Chunshui; Jiang, Tianzi

    2015-01-01

    The Disrupted-in-Schizophrenia 1 (DISC1) gene has been thought as a putative susceptibility gene for various psychiatric disorders, and DISC1 Ser704Cys is associated with variations of brain morphology and function. Moreover, our recent diffusion magnetic resonance imaging (dMRI) study reported that DISC1 Ser704Cys was associated with information transfer efficiency in the brain anatomical network. However, the effects of the DISC1 gene on functional brain connectivity and networks, especially for thalamic-prefrontal circuit, which are disrupted in various psychiatric disorders, are largely unknown. Using a functional connectivity density (FCD) mapping method based on functional magnetic resonance imaging data in a large sample of healthy Han Chinese subjects, we first investigated the association between DISC1 Ser704Cys and short- and long-range FCD hubs. Compared with Ser homozygotes, Cys-allele individuals had increased long-range FCD hubs in the bilateral thalami. The functional and anatomical connectivity of the thalamus to the prefrontal cortex was further analyzed. Significantly increased thalamic-prefrontal functional connectivity and decreased thalamic-prefrontal anatomical connectivity were found in DISC1 Cys-allele carriers. Our findings provide consistent evidence that the DISC1 Ser704Cys polymorphism influences the thalamic-prefrontal circuits in humans and may provide new insights into the neural mechanisms that link DISC1 and the risk for psychiatric disorders. PMID:24146131

  14. A biochemical/biophysical 3D FE intervertebral disc model.

    PubMed

    Schroeder, Y; Huyghe, J M; van Donkelaar, C C; Ito, K

    2010-10-01

    Present research focuses on different strategies to preserve the degenerated disc. To assure long-term success of novel approaches, favorable mechanical conditions in the disc tissue are essential. To evaluate these, a model is required that can determine internal mechanical conditions which cannot be directly measured as a function of assessable biophysical characteristics. Therefore, the objective is to evaluate if constitutive and material laws acquired on isolated samples of nucleus and annulus tissue can be used directly in a whole-organ 3D FE model to describe intervertebral disc behavior. The 3D osmo-poro-visco-hyper-elastic disc (OVED) model describes disc behavior as a function of annulus and nucleus tissue biochemical composition, organization and specific constituent properties. The description of the 3D collagen network was enhanced to account for smaller fibril structures. Tissue mechanical behavior tests on isolated nucleus and annulus samples were simulated with models incorporating tissue composition to calculate the constituent parameter values. The obtained constitutive laws were incorporated into the whole-organ model. The overall behavior and disc properties of the model were corroborated against in vitro creep experiments of human L4/L5 discs. The OVED model simulated isolated tissue experiments on confined compression and uniaxial tensile test and whole-organ disc behavior. This was possible, provided that secondary fiber structures were accounted for. The fair agreement (radial bulge, axial creep deformation and intradiscal pressure) between model and experiment was obtained using constitutive properties that are the same for annulus and nucleus. Both tissue models differed in the 3D OVED model only by composition. The composition-based modeling presents the advantage of reducing the numbers of material parameters to a minimum and to use tissue composition directly as input. Hence, this approach provides the possibility to describe internal

  15. 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

  16. 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

  17. [Simultaneous operation of WPW syndrome combined with mitral regurgitation caused by infective endocarditis].

    PubMed

    Sueda, T; Nakashima, Y; Hamanaka, Y; Ishihara, H; Matsuura, Y; Isobe, F

    1990-03-01

    A case of WPW syndrome combined with mitral regurgitation caused by infective endocarditis underwent surgical division of accessory pathway and mitral valve replacement preserving posterior leaflet simultaneously. A 56-years old woman suffered atrial fibrillation with pseudo VT and cardiac failure caused by mitral regurgitation. Electro-physiological study (EPS) revealed accessory pathway in postero-lateral wall in left atrium and atrio-fascicular pathway like James bundle in AV node. ECHO cardiography showed mitral valve prolapse and severe regurgitation. Accessory pathway was divided surgically and deep freeze coagulation was followed. Perforation of anterior leaflet and chordal rupture of posterior leaflet caused by infective endocarditis were repaired by annuloplasty (Kay and McGoon method) at first, but regurgitation retained moderately. After re-clamping of aorta, mitral valve was replaced with prosthesis (SJM 29 mm) preserving posterior leaflet. Postoperative examination revealed division of accessory pathway and no regurgitation of mitral prosthesis. PMID:2348136

  18. Primary Cardiac T-Cell Lymphoma Localized in the Mitral Valve.

    PubMed

    Motomatsu, Yuma; Oishi, Yasuhisa; Matsunaga, Shogo; Onitsuka, Hirofumi; Yamamoto, Hidetaka; Zaitsu, Eiko; Yamada, Yuichi; Kohashi, Kenichi; Oda, Yoshinao; Tominaga, Ryuji

    2016-06-01

    Primary cardiac lymphoma is a rare cardiac tumor, and usually originates from B cells and involves the right side of the heart. We present an extremely rare case of primary cardiac T-cell lymphoma involving the mitral valve alone. A 58-year-old woman who was positive for human T-cell leukemia virus 1 underwent mitral valve replacement because of severe mitral regurgitation. The postoperative pathologic diagnosis of the mitral valve was T-cell lymphoma. Further evaluation revealed no malignancy, except for the mitral valve. To the best of our knowledge, this is the first case of primary cardiac T-cell lymphoma localized in the mitral valve. PMID:27211945

  19. 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. PMID:24412045

  20. Counter-rotating accretion discs

    NASA Astrophysics Data System (ADS)

    Dyda, S.; Lovelace, R. V. E.; Ustyugova, G. V.; Romanova, M. M.; Koldoba, A. V.

    2015-01-01

    Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud on to the surface of an existing corotating disc or from the counter-rotating gas moving radially inwards to the outer edge of an existing disc. At the interface, the two components mix to produce gas or plasma with zero net angular momentum which tends to free-fall towards the disc centre. We discuss high-resolution axisymmetric hydrodynamic simulations of viscous counter-rotating discs for the cases where the two components are vertically separated and radially separated. The viscosity is described by an isotropic α-viscosity including all terms in the viscous stress tensor. For the vertically separated components, a shear layer forms between them and the middle part of this layer free-falls to the disc centre. The accretion rates are increased by factors of ˜102-104 over that for a conventional disc rotating in one direction with the same viscosity. The vertical width of the shear layer and the accretion rate are strongly dependent on the viscosity and the mass fraction of the counter-rotating gas. In the case of radially separated components where the inner disc corotates and the outer disc rotates in the opposite direction, a gap between the two components opens and closes quasi-periodically. The accretion rates are ≳25 times larger than those for a disc rotating in one direction with the same viscosity.

  1. Have protoplanetary discs formed planets?

    NASA Astrophysics Data System (ADS)

    Greaves, J. S.; Rice, W. K. M.

    2010-09-01

    It has recently been noted that many discs around T Tauri stars appear to comprise only a few Jupiter masses of gas and dust. Using millimetre surveys of discs within six local star formation regions, we confirm this result, and find that only a few per cent of young stars have enough circumstellar material to build gas giant planets, in standard core accretion models. Since the frequency of observed exoplanets is greater than this, there is a `missing-mass' problem. As alternatives to simply adjusting the conversion of dust flux to disc mass, we investigate three other classes of solution. Migration of planets could hypothetically sweep up the disc mass reservoir more efficiently, but trends in multiplanet systems do not support such a model, and theoretical models suggest that the gas accretion time-scale is too short for migration to sweep the disc. Enhanced inner-disc mass reservoirs are possible, agreeing with predictions of disc evolution through self-gravity, but not adding to millimetre dust flux as the inner disc is optically thick. Finally, the incidence of massive discs is shown to be higher at the protostellar stages, Classes 0 and I, where discs substantial enough to form planets via core accretion are abundant enough to match the frequency of exoplanets. Gravitational instability may also operate in the Class 0 epoch, where half the objects have potentially unstable discs of >~30 per cent of the stellar mass. However, recent calculations indicate that forming gas giants inside 50 au by instability is unlikely, even in such massive discs. Overall, the results presented suggest that the canonically `protoplanetary' discs of Class II T Tauri stars have globally low masses in dust observable at millimetre wavelengths, and conversion to larger bodies (anywhere from small rocks up to planetary cores) must already have occurred.

  2. Spontaneous regression of herniated lumbar discs: Report of one illustrative case and review of the literature.

    PubMed

    Yang, Xiaohui; Zhang, Qin; Hao, Xiaoning; Guo, Xinghua; Wang, Liping

    2016-04-01

    Lumbar disc herniation (LDH) is a common disease that induces back pain and radicular pain. The most efficient method for the treatment of lumbar disc herniation is still controversial. Spontaneous regression of LDH has been recognized with the advancement of radiological diagnostic tools and can explain the reason of spontaneous relief of symptoms without treatment. The proposed hypotheses are; dehydration, retraction of the disc to the hernia in the annulus fibrosis, enzymatic catabolism and phagocytosis. In this study, the case of a patient with huge lumbar disc hernia regressing by itself has been presented and the potential mechanisms of disc regression have been discussed. PMID:26907997

  3. Genetic and Functional Studies of the Intervertebral Disc: A Novel Murine Intervertebral Disc Model

    PubMed Central

    Pelle, Dominic W.; Peacock, Jacqueline D.; Schmidt, Courtney L.; Kampfschulte, Kevin; Scholten, Donald J.; Russo, Scott S.; Easton, Kenneth J.; Steensma, Matthew R.

    2014-01-01

    Intervertebral disc (IVD) homeostasis is mediated through a combination of micro-environmental and biomechanical factors, all of which are subject to genetic influences. The aim of this study is to develop and characterize a genetically tractable, ex vivo organ culture model that can be used to further elucidate mechanisms of intervertebral disc disease. Specifically, we demonstrate that IVD disc explants (1) maintain their native phenotype in prolonged culture, (2) are responsive to exogenous stimuli, and (3) that relevant homeostatic regulatory mechanisms can be modulated through ex-vivo genetic recombination. We present a novel technique for isolation of murine IVD explants with demonstration of explant viability (CMFDA/propidium iodide staining), disc anatomy (H&E), maintenance of extracellular matrix (ECM) (Alcian Blue staining), and native expression profile (qRT-PCR) as well as ex vivo genetic recombination (mT/mG reporter mice; AdCre) following 14 days of culture in DMEM media containing 10% fetal bovine serum, 1% L-glutamine, and 1% penicillin/streptomycin. IVD explants maintained their micro-anatomic integrity, ECM proteoglycan content, viability, and gene expression profile consistent with a homeostatic drive in culture. Treatment of genetically engineered explants with cre-expressing adenovirus efficaciously induced ex vivo genetic recombination in a variety of genetically engineered mouse models. Exogenous administration of IL-1ß and TGF-ß3 resulted in predicted catabolic and anabolic responses, respectively. Genetic recombination of TGFBR1fl/fl explants resulted in constitutively active TGF-ß signaling that matched that of exogenously administered TGF-ß3. Our results illustrate the utility of the murine intervertebral disc explant to investigate mechanisms of intervertebral disc degeneration. PMID:25474689

  4. Reduced exercise capacity in patients with tricuspid regurgitation after successful mitral valve replacement for rheumatic mitral valve disease.

    PubMed Central

    Groves, P H; Lewis, N P; Ikram, S; Maire, R; Hall, R J

    1991-01-01

    OBJECTIVE--To determine how severe tricuspid regurgitation influences exercise capacity and functional state in patients who have undergone successful mitral valve replacement for rheumatic mitral valve disease. DESIGN--9 patients in whom clinically significant tricuspid regurgitation developed late after mitral valve replacement were compared with 9 patients with no clinical evidence of tricuspid regurgitation. The two groups were matched for preoperative clinical and haemodynamic variables. Patients were assessed by conventional echocardiography, Doppler echocardiography, and a maximal treadmill exercise test in which expired gas was monitored by mass spectrometry. SETTING--University Hospital of Wales, Cardiff. SUBJECTS--18 patients who had been reviewed regularly since mitral valve replacement. MAIN OUTCOME MEASURE--Objective indices of exercise performance including exercise duration, maximal oxygen consumption, anaerobic threshold, and ventilatory response to exercise. RESULTS--Mitral valve prosthetic function was normal in all patients and estimated pulmonary artery systolic pressure and left ventricular function were similar in the two groups. Right ventricular diameter (median (range) 5.0 (4.3-5.6) v 3.7 (3.0-5.4) cm, p less than 0.01) and the incidence of paradoxical septal motion (9/9 v 3/9, p less than 0.01) were greater in the group with severe tricuspid regurgitation. Exercise performance--assessed by exercise duration (6.3 (5.0-10.7) v 12.7 (7.2-16.0) min, p less than 0.01), maximum oxygen consumption (11.2 (7.3-17.8) v 17.7 (11.8-21.4) ml min-1 kg-1, p less than 0.01), and anaerobic threshold (8.3 (4.6-11.4) v 0.7 (7.3-15.5) ml min-1 kg-1, p less than 0.05)--was significantly reduced in the group with severe tricuspid regurgitation. The ventilatory response to exercise was greater in patients with tricuspid regurgitation (minute ventilation at the same minute carbon dioxide production (41.0 (29.9-59.5) v 33.6 (26.8-39.3) l/min, p less than 0

  5. Disc edge veins of Kraupa associated with optic disc drusen

    PubMed Central

    Díaz, Andrea; Almela, Miguel Angel

    2014-01-01

    Objective: Disc edge veins of Kraupa are a rare anomaly of the retinal venous system in which the main trunk of the retinal vein disappeared into the margin of the optic disc instead of its centre. Methods: A 40-year-old woman was detected to have an anomaly in her left optic disc in a routine eye examination. The eyes had an anomaly of the retinal venous system in which all branches of the retinal vein joined in a common trunk that entered the disc margin inferonasally. The central retinal artery issued from the centre of the disc separately of the venous system. B-scan ultrasonografhy revealed the presence of hyperechoic imaging at the optic nerve head in both eyes. Results: We describe the association of disc edge veins of Kraupa with optic disc drusen. Conclusion: Vascular complications of optic disc drusen hav been described. We don’t know the implication of disc edge veins in the pathogenesis of these complications.

  6. 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.

  7. Robotic Tissue Tracking for Beating Heart Mitral Valve Surgery

    PubMed Central

    Yuen, Shelten G.; Vasilyev, Nikolay V.; del Nido, Pedro J.; Howe, Robert D.

    2010-01-01

    The rapid motion of the heart presents a significant challenge to the surgeon during intracardiac beating heart procedures. We present a 3D ultrasound-guided motion compensation system that assists the surgeon by synchronizing instrument motion with the heart. The system utilizes the fact that certain intracardiac structures, like the mitral valve annulus, have trajectories that are largely constrained to translation along one axis. This allows the development of a real-time 3D ultrasound tissue tracker that we integrate with a 1 degree-of-freedom (DOF) actuated surgical instrument and predictive filter to devise a motion tracking system adapted to mitral valve annuloplasty. In vivo experiments demonstrate that the system provides highly accurate tracking (1.0 mm error) with 70% less error than manual tracking attempts. PMID:23973122

  8. The "loop with anchor" technique to repair mitral valve prolapse.

    PubMed

    Isoda, Susumu; Osako, Motohiko; Kimura, Tamizo; Mashiko, Yuji; Yamanaka, Nozomu; Nakamura, Shingo; Maehara, Tadaaki

    2012-01-01

    The current surgical technique of using an artificial chord (composed of expanded polytetrafluoroethylene [ePTFE] sutures) to repair mitral prolapse is technically difficult to perform. Slippery knot tying and the difficulty of changing the chordae length after the hydrostatic test are frustrating problems. The loop technique solves the problem of slippery knot tying but not the problem of changing the chordae length. Our "loop with anchor" technique consists of the following elements: construction of an anchor at the papillary muscle; determining the loop length; tying the loop to the anchor; suturing the loop to the mitral valve; the hydrostatic test; and re-suturing or changing the loop, if needed. Adjustments can be made for the entire procedure or for a portion of the procedure. PMID:22156285

  9. Computed tomography assessment for transcatheter mitral valve interventions.

    PubMed

    Narang, Akhil; Guerrero, Mayra; Feldman, Ted; Pursnani, Amit

    2016-06-01

    Multidetector cardiac computerized tomography (CT) is a robust advanced imaging modality with high spatial resolution that has emerged as an essential tool for the planning of structural heart and electrophysiology interventions. The most notable example has been its important role in the pre-procedural planning of transcatheter aortic valve replacement (TAVR), which has developed to the point that commercial software packages are commonly used for this application. More recently several novel approaches and devices have been developed for transcatheter mitral valve replacement (TMVR). Given the greater complexity of mitral valve anatomy, CT has at least an equally important role for preprocedural planning of TMVR. Similar to TAVR assessment, its utility in TMVR is multi-fold, including assessment of valve and adjacent anatomical structures, determination of accurate annulus dimensions for prosthesis sizing, vascular access planning, and prediction of fluoroscopic angles. PMID:27028331

  10. 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. PMID:27547149

  11. Infective Endocarditis of the Aortic Valve with Anterior Mitral Valve Leaflet Aneurysm

    PubMed Central

    Li, Wilson W.L.; van Paridon, Marieke; Bindraban, Navin R.; de Mol, Bas A.J.M.

    2016-01-01

    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. PMID:27547149

  12. Emergent presentation of decompensated mitral valve prolapse and atrial septal defect.

    PubMed

    Kang, Jessie; Das, Bijon

    2015-05-01

    Mitral valve prolapse is not commonly on the list of differential diagnosis when a patient presents in the emergency department (ED) in severe distress, presenting with non-specific features such as abdominal pain, tachycardia and dyspnea. A healthy 55-year-old man without significant past medical history arrived in the ED with a unique presentation of a primary mitral valve prolapse with an atrial septal defect uncommon in cardiology literature. Early recognition of mitral valve prolapse in high-risk patients for severe mitral regurgitation or patients with underlying cardiovascular abnormalities such as an atrial septal defect is crucial to prevent morbid outcomes such as sudden cardiac death. PMID:25987923

  13. Stress test for the intervertebra disc joint core

    NASA Astrophysics Data System (ADS)

    Yang, Guobiao; Fang, Ruhua

    2002-05-01

    The inter-vertebra disc is an important part of human lumbar spine, it is valuable to examine the lumbar spine and inter- vertebra disc by means of bio-mechanics. A new testing method is described in this paper for inner stress measuring, the test data is verified by the other test method, which is satisfying, which is satisfying. The results of this paper establish the foundation of the inter-vertebra disc core study, and it is helpful in the clinic and practical application.

  14. Emerging technologies for molecular therapy for intervertebral disc degeneration

    PubMed Central

    Bae, Won C.; Masuda, Koichi

    2014-01-01

    Intervertebral discs are biologically regulated by the maintenance of a balance between the anabolic and catabolic activities of disc cells. Therapeutic agents, initially evaluated using in vitro studies on disc cells and explants, have been used as intradiscal injections in preclinical settings to test in vivo efficacy. These include anabolic growth factors and other biostimulatory agents as well as antagonistic agents against matrix-degrading enzymes and cytokines. Additional work is needed to identify suitable patient populations, using methods such as MRI, and to better understand the mechanism of healing. Clinical trials are currently underway for a few of these agents, while many other promising candidates are on the horizon. PMID:21944594

  15. 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

  16. Myocardial imaging artifacts caused by mitral valve annulus calcification

    SciTech Connect

    Wagoner, L.E.; Movahed, A.; Reeves, W.C. )

    1991-02-01

    Knowledge of imaging artifact of myocardial perfusion studies with thallium-201 is critical for improving the diagnostic accuracy of coronary artery disease. Three patients are described who underwent exercise or pharmacologic stress thallium-201 imaging studies and had a moderate, fixed myocardial perfusion defect (scar) involving the posterolateral and inferoposterior walls of the left ventricle. This was an imaging artifact caused by a heavily calcified mitral valve annulus.

  17. Reversion of Severe Mitral Insufficiency in Peripartum Cardiomyopathy Using Levosimendan

    PubMed Central

    Nieto Estrada, Victor H.; Molano Franco, Daniel L.; Valencia Moreno, Albert Alexander; Rojas Gambasica, Jose A.; Jaller Bornacelli, Yamil E.; Martinez Del Valle, Anacaona

    2015-01-01

    Idiopathic peripartum cardiomyopathy presenting with heart failure is a true diagnostic and treatment challenge. Goal oriented clinical management aims at the relapse of left ventricular systolic dysfunction. A 35-year-old patient on her 12th day post-delivery presents progressive signs of heart failure. Transthoracic echocardiography showed severe mitral insufficiency, mild left ventricular dysfunction, mild tricuspid insufficiency, severe pulmonary hypertension, and right atrial enlargement. With wet and cold heart failure signs, the patient was a candidate for inodilator cardiovascular support and volume depletion therapy. As the patient presented a persistent tachycardia at rest, levosimendan was chosen over dobutamine. Levosimendan was administered at a dose of 0.2 µg/kg/min during a period of 24 hours. After inodilator therapy, the patient’s signs and symptoms of heart failure began to decrease, showing improvement of dyspnea, mitral murmur grade went from IV/IV to II/IV, filling pressures and systemic and pulmonary resistance indexes decreased, arterial blood gases improved, and an echocardiography performed 72 h later showed non-dilated cardiomyopathy, mild cardiac contractile dysfunction, mild mitral insufficiency, type I diastolic dysfunction and improvement of pulmonary hypertension. Cardiovascular function in peripartum cardiomyopathy tends to go back to normality in 23-41% of the cases, but in a large group of patients, severe ventricle dysfunction remains months after initial symptoms. This article describes the diagnostic process of a patient with peripartum cardiomyopathy and a successful reversion of a severe case of mitral insufficiency using levosimendan as a new therapeutic strategy in this clinical context. PMID:26566415

  18. Percutaneous Treatment of Mitral Regurgitation: Current Status and Future Directions

    PubMed Central

    Soni, Lori K.; Argenziano, Michael

    2015-01-01

    The burgeoning field of catheter-based, percutaneous valve intervention takes an interdisciplinary approach to mitral valve regurgitation with the goal of maximizing clinical outcomes and minimizing procedure-associated morbidity. This exciting field continues to push the boundaries of technological innovation as it expands the armamentarium available to treat valvular disease. Around the world teams are working to create a catheter-based approach that is practical and durable. Several technologies are in various stages of development and clinical application. PMID:22443644

  19. Personalized Computational Modeling of Mitral Valve Prolapse: Virtual Leaflet Resection

    PubMed Central

    Rim, Yonghoon; Choi, Ahnryul; McPherson, David D.; Kim, Hyunggun

    2015-01-01

    Posterior leaflet prolapse following chordal elongation or rupture is one of the primary valvular diseases in patients with degenerative mitral valves (MVs). Quadrangular resection followed by ring annuloplasty is a reliable and reproducible surgical repair technique for treatment of posterior leaflet prolapse. Virtual MV repair simulation of leaflet resection in association with patient-specific 3D echocardiographic data can provide quantitative biomechanical and physiologic characteristics of pre- and post-resection MV function. We have developed a solid personalized computational simulation protocol to perform virtual MV repair using standard clinical guidelines of posterior leaflet resection with annuloplasty ring implantation. A virtual MV model was created using 3D echocardiographic data of a patient with posterior chordal rupture and severe mitral regurgitation. A quadrangle-shaped leaflet portion in the prolapsed posterior leaflet was removed, and virtual plication and suturing were performed. An annuloplasty ring of proper size was reconstructed and virtual ring annuloplasty was performed by superimposing the ring and the mitral annulus. Following the quadrangular resection and ring annuloplasty simulations, patient-specific annular motion and physiologic transvalvular pressure gradient were implemented and dynamic finite element simulation of MV function was performed. The pre-resection MV demonstrated a substantial lack of leaflet coaptation which directly correlated with the severe mitral regurgitation. Excessive stress concentration was found along the free marginal edge of the posterior leaflet involving the chordal rupture. Following the virtual resection and ring annuloplasty, the severity of the posterior leaflet prolapse markedly decreased. Excessive stress concentration disappeared over both anterior and posterior leaflets, and complete leaflet coaptation was effectively restored. This novel personalized virtual MV repair strategy has great

  20. 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.

  1. 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.

  2. Edge-on thick discs

    NASA Astrophysics Data System (ADS)

    Kasparova, A.; Katkov, I.; Chilingarian, I.; Silchenko, O.; Moiseev, A.; Borisov, S.

    2016-06-01

    Although thick stellar discs are detected in nearly all edge-on disc galaxies, their formation scenarios still remain a matter of debate. Due to observational difficulties, there is a lack of information about their stellar populations. Using the Russian 6-m telescope BTA we collected deep spectra of thick discs in three edge-on early-type disc galaxies located in different environments: NGC4111 in a dense group, NGC4710 in the Virgo cluster, and NGC5422 in a sparse group. We see intermediate age (4 ‑ 5 Gyr) metal rich ([Fe/H] ~ ‑0.2 ‑ 0.0 dex) stellar populations in NGC4111 and NGC4710. On the other hand, NGC5422 does not harbour young stars, its only disc is thick and old (10 Gyr) and its α-element abundance suggests a long formation epoch implying its formation at high redshift. Our results prove the diversity of thick disc formation scenarios.

  3. [TECHNIQUES IN MITRAL VALVE REPAIR VIA A MINIMALLY INVASIVE APPROACH].

    PubMed

    Ito, Toshiaki

    2016-03-01

    In mitral valve repair via a minimally invasive approach, resection of the leaflet is technically demanding compared with that in the standard approach. For resection and suture repair of the posterior leaflet, premarking of incision lines is recommended for precise resection. As an alternative to resection and suture, the leaflet-folding technique is also recommended. For correction of prolapse of the anterior leaflet, neochordae placement with the loop technique is easy to perform. Premeasurement with transesophageal echocardiography or intraoperative measurement using a replica of artificial chordae is useful to determine the appropriate length of the loops. Fine-tuning of the length of neochordae is possible by adding a secondary fixation point on the leaflet if the loop is too long. If the loop is too short, a CV5 Gore-Tex suture can be passed through the loop and loosely tied several times to stack the knots, with subsequent fixation to the edge of the leaflet. Finally, skill in the mitral valve replacement technique is necessary as a back-up for surgeons who perform minimally invasive mitral valve repair. PMID:27295773

  4. Rate of repair in minimally invasive mitral valve surgery

    PubMed Central

    Hohenberger, Wolfgang; Lakew, Fitsum; Batz, Gerhard; Diegeler, Anno

    2013-01-01

    Background Valve repair has been shown to be the method of choice in the treatment of patients with severe mitral valve regurgitation. Minimally invasive surgery has raised skepticism regarding the rate of repair especially for supposedly complex lesions, when anterior leaflet involvement or bileaflet prolapse is present. We sought to review our experience of all our patients presenting with degenerative mitral valve regurgitation and operated on minimally invasively. Method From September 2006 to December 2012, 842 patients (mean age 56.12±11.62 years old) with degenerative mitral valve regurgitation and anterior leaflet (n=82, 9.7%), posterior leaflet (n=688, 81.7%) and bileaflet (n=72, 8.6%) prolapses were operated on using a minimally invasive approach. Results 836 patients had a valve repair (99.3%) and received a concomitant ring annuloplasty (mean size, 33.7; range, 28-40). Six patients (0.7%) underwent valve replacement. Two patients had a re-repair due to MR progression or infective endocarditis. Thirty-day mortality was 0.2% (two patients). There were 60 major adverse events (MAE) (7.1%). Conclusions A minimally invasive approach allows repair of almost all degenerative valves with good short-term outcomes in a tertiary referral center, when using proven and efficient surgical techniques. PMID:24349977

  5. Techniques for ensuring the correct length of new mitral chords.

    PubMed

    Duran, Carlos M G; Pekar, Filip

    2003-03-01

    Repair of degenerative mitral insufficiency has extensively been shown to be superior to replacement. In the majority of cases, the culprit lesion is limited to the posterior mitral leaflet (PML), which is treated with quadrangular resection of the prolapsing PML, annular plication of the corresponding segment of the annulus, and prosthetic annuloplasty. Anterior mitral leaflet (AML) prolapse is less common and is not always considered an indication for repair despite availability of a variety of surgical maneuvers specifically designed for its treatment. Although reliable if properly performed, chordal shortening at the papillary muscle level is technically demanding. Chordal transfer from the PML with the 'flip-over' technique is highly reproducible, but limited by the very frequent presence of an abnormal PML. Although feasible, transfer of an anterior basal chord to the prolapsing free edge assumes that the basal chords can be sectioned with impunity. More recently, chord replacement with expanded polytetrafluoroethylene (PTFE) sutures has become increasingly popular because of its availability, theoretical simplicity, and demonstrated long-term durability. Although papillary and leaflet anchoring of the neo-chord has not been shown to be a problem, the determination of its appropriate length remains intuitive and based on personal experience. Here, simple surgical maneuvers designed to ensure safe and reproducible results of single or multiple chord replacement with PTFE sutures are described. PMID:12701786

  6. Managing mitral regurgitation: focus on the MitraClip device

    PubMed Central

    Magruder, J Trent; Crawford, Todd C; Grimm, Joshua C; Fredi, Joseph L; Shah, Ashish S

    2016-01-01

    Based on the principle of surgical edge-to-edge mitral valve repair (MVR), the MitraClip percutaneous MVR technique has emerged as a minimally invasive option for MVR. This catheter-based system has been widely demonstrated to be safe, although inferior to surgical MVR. Studies examining patients with ≥3+ mitral regurgitation (MR) show that, for all patients treated, freedom from death, surgery, or MR ≥3+ is in the 75%–80% range 1 year following MitraClip implantation. Despite its inferiority to surgical therapy, in high-risk surgical patients, data suggest that the MitraClip system can be employed safely and that it can result in symptomatic improvement in the majority of patients, while not precluding future surgical options. MitraClip therapy also appears to reduce heart failure readmissions in the high-risk cohort, which may lead to an economic benefit. Ongoing study is needed to clarify the impact of percutaneous mitral valve clipping on long-term survival in high-risk populations, as well as its role in other patient populations, such as those with functional MR. PMID:27110142

  7. Mitral valve function following ischemic cardiomyopathy: a biomechanical perspective

    PubMed Central

    Rim, Yonghoon; McPherson, David D.; Kim, Hyunggun

    2014-01-01

    Ischemic mitral valve (MV) is a common complication of pathologic remodeling of the left ventricle due to acute and chronic coronary artery diseases. It frequently represents the pathologic consequences of increased tethering forces and reduced coaptation of the MV leaflets. Ischemic MV function has been investigated from a biomechanical perspective using finite element-based computational MV evaluation techniques. A virtual 3D MV model was created utilizing 3D echocardiographic data in a patient with normal MV. Two types of ischemic MVs containing asymmetric medial-dominant or symmetric leaflet tenting were modeled by altering the configuration of the normal papillary muscle (PM) locations. Computational simulations of MV function were performed using dynamic finite element methods, and biomechanical information across the MV apparatus was evaluated. The ischemic MV with medial-dominant leaflet tenting demonstrated distinct large stress distributions in the posteromedial commissural region due to the medial PM displacement toward the apical-medial direction resulting in a lack of leaflet coaptation. In the ischemic MV with balanced leaflet tenting, mitral incompetency with incomplete leaflet coaptation was clearly identified all around the paracommissural regions. This computational MV evaluation strategy has the potential for improving diagnosis of ischemic mitral regurgitation and treatment of ischemic MVs. PMID:24211876

  8. Percutaneous mitral heart valve repair--MitraClip.

    PubMed

    Doshi, Jay V; Agrawal, Sahil; Garg, Jalaj; Paudel, Rajiv; Palaniswamy, Chandrasekar; Doshi, Tina V; Gotsis, William; Frishman, William H

    2014-01-01

    Mitral regurgitation (MR) is the most common cardiac valvular disease in the United States. Approximately 4 million people have severe MR and roughly 250,000 new diagnoses of MR are made each year. Mitral valve surgery is the only treatment that prevents progression of heart failure and provides sustained symptomatic relief. Mitral valve repair is preferred over replacement for the treatment of MR because of freedom from anticoagulation, reduced long-term morbidity, reduced perioperative mortality, improved survival, and better preservation of left ventricular function compared with valve replacement. A large proportion of patients in need of valve repair or replacement do not undergo such procedures because of a perceived unacceptable perioperative risk. Percutaneous catheter-based methods for valvular pathology that parallel surgical principles for valve repair have been developed over the last few years and have been proposed as an alternate measure in high-risk patients. The MitraClip (Abbott Labs) device is one such therapy and is the subject of this review. PMID:25098200

  9. 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

  10. Assessment of Functional and Behavioral Changes Sensitive to Painful Disc Degeneration

    PubMed Central

    Lai, Alon; Moon, Andrew; Purmessur, Devina; Skovrlj, Branko; Winkelstein, Beth A.; Cho, Samuel K.; Hecht, Andrew C.; Iatridis, James C.

    2015-01-01

    The development of an in vivo rodent discogenic pain model can provide insight into mechanisms for painful disc degeneration. Painful disc degeneration in rodents can be inferred by examining responses to external stimuli, observing pain-related behaviors, and measuring functional performance. This study compared the sensitivity of multiple pain and functional assessment methods to disc disruption for identifying the parameters sensitive to painful disc degeneration in rats. Disc degeneration was induced in rats by annular injury with saline injection. The severity of disc degeneration, pain sensitivity, and functional performance were compared to sham and näve control rats. Saline injection induced disc degeneration with decreased disc height and MRI signal intensity as well as more fibrous nucleus pulposus, disorganized annular lamellae and decreased proteoglycan. Rats also demonstrated increased painful behaviors including decreased hindpaw mechanical and thermal sensitivities, increased grooming, and altered gait patterns with hindpaw mechanical hyperalgesia and duration of grooming tests being most sensitive. This is the first study to compare sensitivities of different pain assessment methods in an in vivo rat model of disc degeneration. Hindpaw mechanical sensitivity and duration of grooming were the most sensitive parameters to surgically induced degenerative changes and overall results were suggestive of disc degeneration associated pain. PMID:25731955

  11. Numbered nasal discs for waterfowl

    USGS Publications Warehouse

    Bartonek, J.C.; Dane, C.W.

    1964-01-01

    Numbered nasal discs were successfully used in studies requiring large numbers of individually marked waterfowl. The procedure for constructing these discs is outlined. Blue-winged teal (Anas discors) with 5/8-inch discs, and canvasback (Aythya valisineria) and redhead (A. americana) with 3/4-inch discs can be individually identified up to 50 and 80 yards, respectively, with a gunstock-mounted, 20-power spotting scope. The particular value of these markers is their durability, the number of combinations possible, and the apparent absence of behavioral or mortality influence among such species as the blue-winged teal.

  12. Detailed Transthoracic and Transesophageal Echocardiographic Analysis of Mitral Leaflets in Patients Undergoing Mitral Valve Repair.

    PubMed

    Ghulam Ali, Sarah; Fusini, Laura; Tamborini, Gloria; Muratori, Manuela; Gripari, Paola; Mapelli, Massimo; Zanobini, Marco; Alamanni, Francesco; Pepi, Mauro

    2016-07-01

    A recent histological study of resected scallop-P2 in mitral valve (MV) prolapse, showed that chordae tendinae may be missing or hidden in superimposed fibrous tissue of the leaflets, contributing to their thickening. This may have relevant clinical implication because detailed analysis of MV leaflets has a central role in the evaluation of patients undergoing repair. The aim of this study was to analyze MV leaflets focusing on thickness of prolapsing segments and the presence of chordal rupture (CR). We enrolled 246 patients (age 63 ± 13 years, 72 men) with isolated P2 prolapse and also 50 age-matched patients with normal MV anatomy as control group. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were retrospectively analyzed to quantify the length and the proximal and distal thickness of both anterior (A2) and posterior (P2) MV scallops. Measurements were performed at end diastole in the standard TTE and TEE views. TTE and TEE measurements were feasible in all cases. Echocardiographically 176 patients had CR (group A), 45 had no rupture (group B), and 25 had an uncertain diagnosis (group C). All pathological groups showed thickening and elongation of involved leaflets versus normal, whereas no differences in leaflets characteristics were found among MV groups. Most patients undergoing MV repair had CR with thickening of the prolapsed segment. These findings are in agreement with recent histological studies showing superimposed fibrous tissue on MV leaflets partially including ruptured chordae. This may also explain that in cases without ruptured chordae, thickness of the leaflets is markedly increased (hidden chordae?). In conclusion, detailed analysis of MV apparatus may further improve knowledge of these patients and may influence surgical timing. PMID:27184171

  13. Symptomatic Pneumocephalus after Lumbar Disc Surgery: a Case Report

    PubMed Central

    Kizilay, Zahir; Yilmaz, Ali; Ismailoglu, Ozgur

    2015-01-01

    Symptomatic pneumocephalus is frequently seen after traumatic fracture of the skull base bone. However, it has rarely been reported after spinal surgery and its mechanism has not been fully explained. In this paper, we present a 30 year old male patient who had lumbar discectomy due to a symptomatic midline lumbar disc herniation. He had developed symptomatic pneumocephalus after the lumbar disc surgery associated with application of a vacuum suction device. We present and discuss our patient in the light of the literatures.

  14. 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

  15. 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...

  16. Implantation of personalized, biocompatible mitral annuloplasty rings: feasibility study in an animal model

    PubMed Central

    Sündermann, Simon H.; Gessat, Michael; Cesarovic, Nikola; Frauenfelder, Thomas; Biaggi, Patric; Bettex, Dominique; Falk, Volkmar; Jacobs, Stephan

    2013-01-01

    OBJECTIVES Implantation of an annuloplasty ring is an essential component of a durable mitral valve repair. Currently available off-the-shelf rings still do not cover all the variations in mitral annulus anatomy and pathology from subject to subject. Computed tomography (CT) and echo imaging allow for 3-D segmentation of the mitral valve and mitral annulus. The concept of tailored annuloplasty rings has been proposed although, to date, no surgically applicable implementation of patient-specific annuloplasty rings has been seen. The objective of this trial was to prove the concept of surgical implantation of a model-guided, personalized mitral annuloplasty ring, manufactured based on individual CT-scan models. METHODS ECG-gated CT angiography was performed in six healthy pigs under general anaesthesia. Based on the individual shape of the mitral annulus in systole, a customized solid ring with integrated suturing holes was designed and manufactured from a biocompatible titanium alloy by a rapid process using laser melting. The ring was implanted three days later and valve function was assessed by intraoperative echocardiography. The macroscopic annulus–annuloplasty match was assessed after heart explantation. RESULTS CT angiography provided good enough image quality in all animals to allow for segmentation of the mitral annulus. The individually tailored mitral rings were manufactured and successfully implanted in all pigs. In 50%, a perfect matching of the implanted ring and the mitral annulus was achieved. In one animal, a slight deviation of the ring shape from the circumference was seen postoperatively. The rings implanted in the first two animals were significantly oversized but the deviation did not affect valve competence. CONCLUSIONS CT image quality and accuracy of the dimensions of the mitral annulus were sufficient for digital modelling and rapid manufacturing of mitral rings. Implantation of individually tailored annuloplasty rings is feasible. PMID

  17. Predictors of outcome of mitral valve prolapse in patients with the Marfan syndrome.

    PubMed

    Rybczynski, Meike; Treede, Hendrik; Sheikhzadeh, Sara; Groene, Eike F; Bernhardt, Alexander M J; Hillebrand, Mathias; Mir, Thomas S; Kühne, Kristine; Koschyk, Dietmar; Robinson, Peter N; Berger, Jürgen; Reichenspurner, Hermann; Meinertz, Thomas; von Kodolitsch, Yskert

    2011-01-15

    Mitral valve prolapse has a prevalence of 2% to 3% in the general population, with adverse outcomes such as mitral valve regurgitation (MVR), heart failure, and endocarditis. Predictors of outcomes are used in idiopathic mitral valve prolapse for the timing of surgery, but such predictors are unknown in Marfan syndrome. Therefore, a population-based cohort study of 112 patients (49 male, 63 female; mean age 34 ± 15 years) with classic Marfan syndrome and mitral valve prolapse with moderate or less MVR at baseline was conducted. During 4.6 ± 3.6 years of follow-up, progression of MVR was observed in 41 patients and valve-related events, which comprised mitral valve endocarditis (7 events), heart failure (5 events), and mitral valve surgery (25 events), were observed in 31 patients. Multivariate Cox proportional-hazards regression analysis identified a flail mitral leaflet (hazard ratio [HR] 3.262, 95% confidence interval [CI] 1.406 to 7.566, p = 0.006) and increased indexed end-systolic left ventricular diameters (HR 1.113, 95% CI 1.043 to 1.188, p = 0.001) as independent predictors of progression of MVR. Similarly, mitral valve-related events were independently predicted by a flail mitral leaflet (HR 5.343, 95% CI 2.229 to 12.808, p <0.001), and mild (HR 14.336, 95% CI 1.873 to 109.755, p = 0.01) or moderate (HR 16.849, 95% CI 2.205 to 128.76, p = 0.006) degree of MVR. Conversely, aortic dilatation, dural ectasia, and sporadic mode of inheritance were not associated with outcome. In conclusion, the same clinical determinants that predict outcomes in idiopathic mitral valve prolapse also predict outcomes in mitral valve prolapse associated with Marfan syndrome. PMID:21211604

  18. Quantitative MRI as a diagnostic tool of intervertebral disc matrix composition and integrity

    PubMed Central

    Mwale, Fackson; Iatridis, James C.

    2008-01-01

    Degenerative disc disease has been implicated as a major component of spine pathology. The current major clinical procedures for treating disc degeneration have been disappointing, because of altered spinal mechanics leading to subsequent degeneration at adjacent disc levels. Disc pathology treatment is shifting toward prevention and treatment of underlying etiologic processes at the level of the disc matrix composition and integrity and the biomechanics of the disc. The ability to perform such treatment relies on one’s ability to accurately and objectively assess the state of the matrix and the effectiveness of treatment by a non-invasive technique. In this review, we will summarize our advances in efforts to develop an objective, accurate, non-invasive diagnostic tool (quantitative MRI) in the detection and quantification of matrix composition and integrity and of biomechanical changes in early intervertebral disc degeneration. PMID:19005703

  19. Nonlinear fluid/structure interaction relating a rupture-disc pressure-relief device. [LMFBR

    SciTech Connect

    Hsieh, B.J.; Kot, C.A.; Shin, Y.W.; Youngdahl, C.K.

    1983-01-01

    Rupture disc assemblies are used in piping network systems as a pressure-relief device. The reverse-buckling type is chosen for application in a liquid metal fast breeder reactor. This assembly is used successfully in systems in which the fluid is highly compressible, such as air; the opening up of the disc by the knife setup is complete. However, this is not true for a liquid system; it had been observed experimentally that the disc may open up only partially or not at all. Therefore, to realistically understand and represent a rupture disc assembly in a liquid environment, the fluid-structure interactions between the liquid medium and the disc assembly must be considered. The methods for analyzing the fluid and the disc and the mechanism interconnecting them are presented. The fluid is allowed to cavitate through a column-cavitation model and the disc is allowed to become plastically deformed through the classic Von Mises' yield criteria, when necessary.

  20. Grain size segregation in debris discs

    NASA Astrophysics Data System (ADS)

    Thebault, P.; Kral, Q.; Augereau, J.-C.

    2014-01-01

    Context. In most debris discs, dust grain dynamics is strongly affected by stellar radiation pressure. Because this mechanism is size-dependent, we expect dust grains to be spatially segregated according to their sizes. However, because of the complex interplay between radiation pressure, grain processing by collisions, and dynamical perturbations, this spatial segregation of the particle size distribution (PSD) has proven difficult to investigate and quantify with numerical models. Aims: We propose to thoroughly investigate this problem by using a new-generation code that can handle some of the complex coupling between dynamical and collisional effects. We intend to explore how PSDs behave in both unperturbed discs at rest and in discs pertubed by planetary objects. Methods: We used the DyCoSS code to investigate the coupled effect of collisions, radiation pressure, and dynamical perturbations in systems that have reached a steady-state. We considered two setups: a narrow ring perturbed by an exterior planet, and an extended disc into which a planet is embedded. For both setups we considered an additional unperturbed case without a planet. We also investigated the effect of possible spatial size segregation on disc images at different wavelengths. Results: We find that PSDs are always spatially segregated. The only case for which the PSD follows a standard dn ∝ s-3.5ds law is for an unperturbed narrow ring, but only within the parent-body ring itself. For all other configurations, the size distributions can strongly depart from such power laws and have steep spatial gradients. As an example, the geometrical cross-section of the disc is very rarely dominated by the smallest grains on bound orbits, as it is expected to be in standard PSDs in sq with q ≤ -3. Although the exact profiles and spatial variations of PSDs are a complex function of the set-up that is considered, we are still able to derive some reliable results that will be useful for image or SED

  1. Minimally Invasive Mitral Valve Repair in a Marfan Patient with Severe Scoliokyphosis

    PubMed Central

    Noack, Thilo; Lehmkuhl, Lukas; Seeburger, Joerg; Mohr, Friedrich Wilhelm

    2014-01-01

    A 26-year-old female Marfan patient with extensive scoliokyphosis presented with severe mitral valve regurgitation. The patient was treated with minimally invasive mitral valve repair via a right lateral minithoracotomy. In this report, we discuss the operative procedure followed in this special case and the current literature. PMID:25798347

  2. Surgical treatment for mitral stenosis in Scheie's syndrome: mucopolysaccharidosis type I-S.

    PubMed

    Kitabayashi, Katsukiyo; Matsumiya, Goro; Ichikawa, Hajime; Matsue, Hajime; Shimamura, Kazuo; Sawa, Yoshiki

    2007-08-01

    Scheie's syndrome is a subtype of mucopolysaccharidosis, which is a rare hereditary disorder of proteoglycan degrading enzymes. Deposition of mucopolysaccharide often causes cardiac disease, especially valvular lesion, but reports of its surgical treatment have been rare. We report a case of 41-year-old woman with Scheie's syndrome who successfully underwent mitral valve replacement for mitral stenosis. PMID:17643657

  3. Perforated Submitral Left Ventricular Aneurysm Resulting in Severe Mitral Annular Regurgitation

    PubMed Central

    Simpson, Leo; Duncan, J. Michael; Stainback, Raymond F.

    2006-01-01

    Annular submitral left ventricular aneurysm, which predominantly occurs in blacks who live in tropical regions of Africa, is a relatively unknown cardiac condition in the United States. We describe a patient with submitral left ventricular aneurysm who underwent resection of the mass and of the native mitral valve, followed by mitral valve replacement. PMID:17215978

  4. Robotic Septal Myectomy and Mitral Valve Repair for Idiopathic Hypertrophic Subaortic Stenosis With Systolic Anterior Motion.

    PubMed

    Bayburt, Selin; Senay, Sahin; Gullu, Ahmet Umit; Kocyigit, Muharrem; Karakus, Gultekin; Batur, Mustafa Kemal; Alhan, Cem

    2016-01-01

    Combined therapeutic approach with performing mitral valve repair may be necessitated for the treatment of idiopathic hypertrophic subaortic stenosis (IHSS) with systolic anterior motion. This report includes operative technique for combined robotic septal myectomy and mitral valve repair. A 45-year-old man with IHSS was admitted to our center for surgical intervention. The transthoracic echocardiography showed typical asymmetric ventricular hypertrophy. Left ventricle posterior wall thickness was 11 mm, and interventricular septum thickness was 21 mm. Mitral valve leaflets were found to be elongated. Mild-to-severe mitral regurgitation was detected with eccentric mitral jet. Aortic peak gradient was 128 mm Hg. Robotic mitral repair and septal myectomy through left atrial exposure was performed. The anterior leaflet was detached, and the septal muscle in a mass of 1 × 0.7 × 0.5 cm was resected. Next, the anterior leaflet was reattached with continuous suture. The plication of the posterior leaflet with transverse incision was performed to diminish the length of posterior leaflet. After the magic suture for posteromedial commissure was performed, a 34 Medtronic Future ring was implanted for mitral annuloplasty. Postoperative course was uneventful. The patient was discharged on the sixth postoperative day. Combined robotic septal myectomy and mitral valve repair for IHSS with systolic anterior motion may be feasible. PMID:27115534

  5. 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

    2016-01-01

    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

  6. Dynamics of mitral regurgitation during nitroglycerin therapy: a Doppler echocardiographic study.

    PubMed

    Keren, G; Bier, A; Strom, J A; Laniado, S; Sonnenblick, E H; LeJemtel, T H

    1986-09-01

    Seven patients with decompensated chronic heart failure and functional mitral regurgitation were studied before and during administration of nitroglycerin at a mean dose of 42 micrograms/min (range 20 to 90 micrograms/min). Forward aortic flow obtained by pulsed Doppler increased significantly from 35 +/- 8 to 45 +/- 9 ml/beat (p less than 0.001) and correlated well with the cardiac output measured by thermodilution technique (r = 0.8). Whereas regurgitant mitral volume calculated from the difference between echocardiographic total stroke volume and forward aortic flow decreased significantly from 19 +/- 9 to 3 +/- 3 ml/beat (p less than 0.001), peak velocity of mitral regurgitant flow increased from 4.1 +/- 0.9 to 4.4 +/- 1.0 m/sec (p less than 0.05). The decrease in effective mitral regurgitation area derived from a modified Gorlin formula average 80%. Accordingly, in patients with decompensated chronic heart failure and functional mitral regurgitation, nitroglycerin decreases mitral regurgitant area substantially, and thus almost abolishes mitral regurgitation despite an increase in systolic pressure gradient between left ventricle and atrium. Moreover, the increase in forward flow can be entirely accounted for by the reduction in mitral regurgitant flow. PMID:3092608

  7. A controlled evaluation of the risk of bacterial endocarditis in persons with mitral-valve prolapse.

    PubMed

    Clemens, J D; Horwitz, R I; Jaffe, C C; Feinstein, A R; Stanton, B F

    1982-09-23

    The absence of controlled evidence and the high prevalence of mitral-valve prolapse have created substantial uncertainty about whether this condition is an important risk factor for bacterial endocarditis. We evaluated this risk in a case-control study of hospital inpatients who had undergone echocardiography and who lacked any known cardiovascular risk factors for endocarditis, apart from mitral-valve prolapse and isolated mitral-regurgitant murmurs. Thirteen (25 per cent) of 51 patients with endocarditis had mitral-valve prolapse, as compared with 10 (seven per cent) of the 153 matched controls without endocarditis. For the 51 matched case-control sets, the odds ratio (8.2; 95 per cent confidence interval, 2.4 to 28.4) indicated a substantially higher risk of endocarditis for people with mitral-valve prolapse than for those without it. This association remained statistically significant when parenteral drug abuse and routine antibiotic prophylaxis preceding dental work and other forms of instrumentation were taken into account. Furthermore, the risk may be higher than is indicated by this study, since 46 per cent of the controls underwent echocardiography for clinically suspected mitral-valve prolapse, suggesting an overrepresentation of mitral prolapse in the control group. The results support the contention that mitral-valve prolapse is a significant risk factor for bacterial endocarditis. PMID:7110242

  8. Nonlinear fluid/structure interaction relating a rupture-disc pressure-relief device

    SciTech Connect

    Hsieh, B.J.; Kot, C.A.; Shin, Y.W.; Youngdahi, C.K.

    1983-01-01

    Rupture disc assemblies are used in piping network systems as pressure-relief devices. The reverse-buckling type discs are chosen for application in heat transport systems of liquid metal fast breeder reactors. When the pressure on the disc is of sufficient magnitude and duration, the disc develops large displacement, is consequently torn open by a cutting-knife setup and thus relieves the excess pressure. Such disc assemblies are used very successfully in systems in which the fluid is highly compressible, e.g., air; the opening of the disc by the knife setup is complete. However, this is not true for a liquid system; in this case it has been observed experimentally that the disc may open up only partially or not at all. Therefore, to understand and realistically represent a rupture disc assembly in a liquid environment, the fluid-structure interactions between the liquid medium and the disc assembly must be considered. In this paper, methods for analyzing the fluid and the disc and the mechanism interconnecting them are presented. When necessary the fluid is allowed to cavitate through a column separation model and the disc can become plastically deformed using the classic Von Mises' yield criteria.

  9. 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. PMID:26736977

  10. 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. PMID:19431068

  11. Effects of chronic beta-adrenergic blockade on the left ventricular and cardiocyte abnormalities of chronic canine mitral regurgitation.

    PubMed Central

    Tsutsui, H; Spinale, F G; Nagatsu, M; Schmid, P G; Ishihara, K; DeFreyte, G; Cooper, G; Carabello, B A

    1994-01-01

    The mechanism by which beta blockade improves left ventricular dysfunction in various cardiomyopathies has been ascribed to improved contractile function of the myocardium or to improved beta-adrenergic responsiveness. In this study we tested two hypotheses: (a) that chronic beta blockade would improve the left ventricular dysfunction which develops in mitral regurgitation, and (b) that an important mechanism of this effect would be improved innate contractile function of the myocardium. Two groups of six dogs with chronic severe mitral regurgitation were studied. After 3 mo both groups had developed similar and significant left ventricular dysfunction. One group was then gradually beta-blocked while the second group continued to be observed without further intervention. In the group that remained unblocked, contractile function remained depressed. However, in the group that received chronic beta blockade, contractile function improved substantially. The contractility of cardiocytes isolated from the unblocked hearts and then studied in the absence of beta receptor stimulation was extremely depressed. However, contractility of cardiocytes isolated from the beta-blocked ventricles was virtually normal. Consistent with these data, myofibrillar density was much higher, 55 +/- 4% in the beta-blocked group vs. 39 +/- 2% (P < 0.01) in the unblocked group; thus, there were more contractile elements to generate force in the beta-blocked group. We conclude that chronic beta blockade improves left ventricular function in chronic experimental mitral regurgitation. This improvement was associated with an improvement in the innate contractile function of isolated cardiocytes, which in turn is associated with an increase in the number of contractile elements. Images PMID:7911128

  12. Tension to passively cinch the mitral annulus through coronary sinus access: an ex vivo study in ovine model

    PubMed Central

    Bhattacharya, Shamik; Pham, Thuy; He, Zhaoming; Sun, Wei

    2014-01-01

    Introduction The transcatheter mitral valve repair (TMVR) technique utilizes a stent to cinch a segment of the mitral annulus (MA) and reduces mitral regurgitation. The cinching mechanism results in reduction of the septal-lateral distance. However, the mechanism has not been characterized completely. In this study, a method was developed to quantify the relation between cinching tension and MA area in an ex vivo ovine model. Method The cinching tension was measured from a suture inserted within the coronary sinus (CS) vessel with one end tied to the distal end of the vessel and the other end exited to the CS ostium where it was attached to a force transducer on a linear stage. The cinching tension, MA area, septal-lateral (S-L) and commissure-commissure (C-C) diameters and leakage was simultaneously measured in normal and dilated condition, under a hydrostatic left ventricular pressure of 90 mmHg. Results The MA area was increased up to 22.8% after MA dilation. A mean tension of 2.1 ± 0.5 N reduced the MA area by 21.3 ± 5.6% and S-L diameter by 24.2 ± 5.3%. Thus, leakage was improved by 51.7 ± 16.2 % following restoration of normal MA geometry. Conclusion The cinching tension generated by the suture acts as a compensation force in MA reduction, implying the maximum tension needed to be generated by annuloplasty device to restore normal annular size. The relationship between cinching tension and the corresponding MA geometry will contribute to the development of future TMVR devices and understanding of myocardial contraction function. PMID:24607007

  13. CT and MR imaging of the mitral valve: radiologic-pathologic correlation.

    PubMed

    Morris, Michael F; Maleszewski, Joseph J; Suri, Rakesh M; Burkhart, Harold M; Foley, Thomas A; Bonnichsen, Crystal R; Anavekar, Nandan S; Young, Phillip M; Williamson, Eric E; Glockner, James F; Araoz, Philip A

    2010-10-01

    Computed tomography (CT) and magnetic resonance (MR) imaging are increasingly important adjuncts to echocardiography for the evaluation of mitral valve disease. The mitral valve may be involved in various acquired or congenital conditions with resultant regurgitation or stenosis, and many of these conditions can be identified with CT or MR imaging. In addition, CT is useful for detecting and monitoring postoperative complications after mitral valve repair or replacement. As the use of CT and MR imaging increases, awareness of the CT and MR imaging appearances of the normal mitral valve and the various disease processes that affect it may foster recognition of unsuspected mitral disease in patients undergoing imaging for other purposes. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.306105518/-/DC1. PMID:21071378

  14. 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. PMID:27081025

  15. 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

  16. Spontaneous Remission of a Big Subligamentous Extruded Disc Herniation: Case Report and Review of the Literature

    PubMed Central

    İbrahimoğlu, Muhammet

    2015-01-01

    Spontaneous Regression of a Big Subligamentous Extruded Disc Herniation: Case Report And Review of The Literature The most efficient method for the treatment of lumbar disc herniation is still controversial. The most important aspect is the application of the suitable conservative or surgical treatment to the right patient at the right time. In lumbar disc herniation patients, one must not precipitate except for cases that require surgical indications as in cauda equina syndrome, evolutive motor deficit and persistence of pain in spite of the narcotics. However, the spontaneous regression mechanism has not been completely determined yet. The proposed hypotheses are; dehydration, retraction of the disc to the hernia in the annulus fibrosis, enzymatic catabolism and phagocytosis. In this study, the case of a patient with huge lumbar disc hernia regressing by itself has been presented and the potential mechanisms of disc regression have been discussed. PMID:25883664

  17. Acute LVOT Obstruction with a Carbomedics Mechanical Valve Prosthesis.

    PubMed

    Alsidawi, Said; Joyce, David L; Malouf, Joseph F; Nkomo, Vuyisile T

    2016-06-01

    A 62-year-old female with severe symptomatic rheumatic mitral stenosis was referred for mitral valve replacement. A 27-mm Carbomedics mechanical mitral valve was placed using everting sutures. As the patient was weaned off cardiopulmonary bypass, she became hemodynamically unstable. Intraoperative transesophageal echocardiogram revealed a significant drop in left ventricular function along with severe LVOT obstruction. The Carbomedics prosthesis was replaced by a 27-mm St. Jude mechanical valve using noneverting sutures which relieved the LVOT obstruction. doi: 10.1111/jocs.12749 (J Card Surg 2016;31:376-379). PMID:27087635

  18. 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.

  19. 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) PMID:3766410

  20. [The role of connective tissue dysplasia in the forming of mitral valve prolapse].

    PubMed

    Filipenko, P S; Malookaia, Iu S

    2006-01-01

    Connective tissue (CT) is a multifunctional universal structure of great importance to the human organism. Constituting about 50% of the body mass, CT forms a frame (skeleton) and outer cover (skin), as well as the inner medium, through which all structural elements receive nutrients and extract metabolic products. The great number of links, constituting the CT system, each of which is controlled genetically and is liable to genetic lesions, creates conditions for heterogeneity of malformations and diseases involving CT. Non-differentiated CT dysplasia (NDCTD) is a genetically heterogenous group, presenting a basis for various chronic diseases. NDCTD may present the cause of dysplastic changes in the CT of different organs and systems. Thanks to modern diagnostic techniques, NDCTD is revealed frequently. NDCTD is underlied by molecular-, onto-, and pathogenetic mechanisms, leading to structural and functional changes in CT. This CT "weakness" is manifested by the peculiarities of the structure of various organs and systems. Mesenchimal heart dysplasias are the most widespread visceral markers of the given CT pathology. CT dysplasias of the heart are often combined with varied manifestations of system CT anomaly. Mitral valve prolapse (MVP) is the most wide-spread and well-studied minor heart anomalies. Primary MVP is a hereditary or congenital pathology and is not connected with a particular disease. It is a genetic pathology--CT dysplasia with autosomal dominant inheritance. Patients with MVP have an increased expression of Bw35 antigen of HLA system, which causes dysmetabolism of collagen in the mitral cusps. It has been revealed that tissue deficiency of magnesium is associated with antigen expression and correlates with clinical symptoms in MVP. Exogenic factors influencing MVP have been described. PMID:17294876

  1. Left ventricular outflow track obstruction and mitral valve regurgitation in a patient with takotsubo cardiomyopathy

    PubMed Central

    Wu, Yin; Fan, WuQiang; Chachula, Laura; Costacurta, Gary; Rohatgi, Rajeev; Elmi, Farhad

    2015-01-01

    Introduction Takotsubo cardiomyopathy (TCM) can be complicated by left ventricular outflow tract (LVOT) obstruction and severe acute mitral regurgitation (MR), leading to hemodynamic instability in an otherwise benign disorder. Despite the severity of these complications, there is a paucity of literature on the matter. Because up to 20–25% of TCM patients develop LVOT obstruction and/or MR, it is important to recognize the clinical manifestations of these complications and to adhere to specific management in order to reduce patient morbidity and mortality. We report the clinical history, imaging, treatment strategy, and clinical outcome of a patient with TCM that was complicated with severe MR and LVOT obstruction. We then discuss the pathophysiology, characteristic imaging, key clinical features, and current treatment strategy for this unique patient population. Case report A postmenopausal woman with no clear risk factor for coronary artery disease (CAD) presented to the emergency department with chest pain after an episode of mental/physical stress. Physical examination revealed MR, mild hypotension, and pulmonary vascular congestion. Her troponins were mildly elevated. Cardiac catheterization excluded obstructive CAD, but revealed severe apical hypokinesia and ballooning. Notably, multiple diagnostic tests revealed the presence of severe acute MR and LVOT obstruction. The patient was diagnosed with TCM complicated by underlying MR and LVOT obstruction, and mild hemodynamic instability. The mechanism of her LVOT and MR was attributed to systolic anterior motion of the mitral valve (SAM), which the transesophageal echocardiogram clearly showed during workup. She was treated with beta-blocker, aspirin, and ACE-I with good outcome. Nitroglycerin and inotropes were discontinued and further avoided. Conclusions Our case illustrated LVOT obstruction and MR associated with underlying SAM in a patient with TCM. LVOT obstruction and MR are severe complications of TCM

  2. 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

  3. Chorea in a pregnant woman with rheumatic mitral stenosis.

    PubMed

    Fam, Neil P; Chisholm, Robert J

    2003-05-01

    Chorea gravidarum is a rare movement disorder of pregnancy with a broad differential diagnosis. Although often a benign condition, it may indicate underlying acute rheumatic fever, antiphospholipid antibody syndrome or a hypercoagulable state. However, now that rheumatic fever is rare in western countries, chorea gravidarum occurs most commonly in patients with chronic rheumatic heart disease. Heightened awareness of chorea gravidarum and the morbidity of the often associated rheumatic heart disease, particularly in immigrants from developing countries, is essential for early diagnosis and effective management. A case of chorea gravidarum in a woman with rheumatic mitral stenosis is described. The diagnostic approach, pathophysiology and management of this rare condition are discussed. PMID:12772024

  4. [National registry of percutaneous mitral commissurotomy. 8-year's experience].

    PubMed

    Ledesma Velasco, M; Treviño Treviño, A; Delgado Caro, G; Martínez Ríos, M A; Murillo Márquez, H; Munayer Calderón, J; de Zatarain Rivero, R; Encarnación Muñoz, B

    1996-01-01

    From April 1986 to June 1994 we performed percutaneous transvenous mitral commissurotomy in 689 patients with rheumatic mitral stenosis in a multicenter study. Mean age was 40 +/- 11 years, of then 84.9% female, 2.7% to had previous surgical treatment and in 1.4% the procedure was performed during pregnancy. Inoue balloon was used in 89.4%, double balloon 9.7% and monoballoon 0.9%. Mitral valve area (MVA) increased from 0.93 +/- 0.20 to 1.85 +/- 0.37 cm2 (p < 0.001) and mean pulmonary artery pressure from 31.5 +/- 15.8 to 22.4 +/- 11.5 mmHg (p < 0.001), mean left atrial pressure decreased from 20.9 +/- 8.1 to 10.0 +/- 5.9 mmHg (p < 0.001), transvalvular gradient (TVG) from 15.4 +/- 6.4 to 3.4 +/- 3.1 mmHg (p < 0.001) and mean pulmonary artery pressure from 31.5 +/- 15.8 to 22.4 +/- 11.5 mmHg (p < 0.001). Complete procedure without mayor complications was achieved in 93.1%. Severe mitral regurgitation (MR) was present in 3.9%. Optimal result in 82.1%, suboptimal in 8.2% and failure in 9.7%. Major complications 4.7%. Mortality was 0.9%. Six months follow-up MVA decreased to 1.77 +/- 0.38 (p < 0.001) and no changes to 24 months (1.78 +/- 0.37 p ns). Twenty four months follow-up 93.3% are in NYHA class I. Only MVA (> 1 cm2) and good predilatation NYHA class were predictors of optimal results. Severe MR were more frecuently in patients with atrial fibrillation and with high score (> 8). Our results were similar the international experience. We conclude that the technique of PTMC is a safe and effective technique. PMID:8967819

  5. Three-Dimensional Transesophageal Echocardiography in the Anatomical Assessment of Isolated Parachute Mitral Valve in an Adult Patient.

    PubMed

    López-Pardo, Francisco; Urbano-Moral, Jose Angel; González-Calle, Antonio; Laviana-Martinez, Fernando; Esteve-Ruiz, Iris; Lagos-Degrande, Oscar; López-Haldon, Jose E

    2015-11-01

    Parachute mitral valve (PMV) is a rare congenital anomaly of the mitral valve apparatus usually evidenced in infants and young children. Adult presentation is extremely rare and is generally mild in terms of mitral stenosis. A 73-year-old woman was admitted to the emergency department due to progressive dyspnea, with NYHA functional class IV symptoms on presentation. The echocardiographic examination identified a PMV with moderate mitral stenosis and a secondary smaller subvalvular mitral orifice. The report shows the usefulness of three-dimensional transesophageal echocardiography in the detection and quantification of this rare anomaly. PMID:26096823

  6. A Rare Association of Parachute Mitral Valve with Double Outlet Right Ventricle and Severe Pulmonary Hypertension in an Adult.

    PubMed

    Meenakshi, K; Chidambaram, Sundar; Dhandapani, V E; Rameshwar, R

    2014-11-01

    Congenital mitral stenosis (MS) is a rare congenital cardiac malformation and the obstruction to the flow across the mitral valve can be caused by supramitral ring, commissural fusion, short chordae, anomalous mitral arcade, anomalous position of the papillary muscles and the so-called'parachute mitral valve'. We describe here the case of a 47 year old male diagnosed to have a double outlet right ventricle (DORV), subaortic ventricular septal defect (VSD) with no pulmonary stenosis, severe pulmonary hypertension and congenital MS due to parachute mitral valve. PMID:26281483

  7. 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.

  8. Discs in misaligned binary systems

    NASA Astrophysics Data System (ADS)

    Rawiraswattana, Krisada; Hubber, David A.; Goodwin, Simon P.

    2016-08-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-alignment processes, which tend to misalign the components. The alignment process dominates in systems with misalignment angle near 90°, while the anti-alignment process dominates in systems with the misalignment angle near 0° or 180°. This means that highly misaligned systems will become more aligned but slightly misaligned systems will become more misaligned.

  9. Lumbar percutaneous KTP532 wavelength laser disc decompression and disc ablation in the management of discogenic pain.

    PubMed

    Knight, Martin; Goswami, Ankul

    2002-02-01

    The objective of this research was to determine the outcome of laser disc decompression and laser disc ablation in the management of painful degenerative disc disease with or without associated disc prolapse. Nonendoscopic percutaneous laser disc decompression was performed under x-ray control via the posterolateral approach with side-firing probes. All patients with chronic back pain who had reproduced pain during discography of a nature, pattern, and distribution similar to what they experienced normally were included in the study. Magnetic resonance which confirmed stenosis and sequestrated discs, and patients with acute neurological findings were excluded from the study. Laser disc decompression or ablation was done using the KTP532 wavelength. The functional outcome was assessed prospectively using the Oswestry Disability Index. Clinical benefit was considered significant in those patients with a percentage change in the index of > or =50% at review 3-9 years (mean, 5.33 years) following surgery. A total of 52% of patients demonstrated a sustained significant clinical benefit, with an additional 21% in whom functional improvement was noted. Cohort integrity was 67%. Long-term benefit of the laser disc ablation and decompression for discogenic pain suggests a mechanism other than principally mechanical as a cause of chronic back and sciatic pain. It may suggest that efficacy occurs by reduction in the intradiscal production of irritative products and by an effect upon discal and annular neoneuralization. The sustained nature of the benefit after long-term preoperative symptoms (mean, 4.7 years) rules out any placebo effect. Selection should be restricted to patients without significant lateral recess stenosis, retrolisthesis or olisthesis of > or =3 mm, significant dorsal or foraminal osteophytosis, extrusion, or sequestration. PMID:11902355

  10. The Effect of Sustained Compression on Oxygen Metabolic Transport in the Intervertebral Disc Decreases with Degenerative Changes

    PubMed Central

    Malandrino, Andrea; Noailly, Jérôme; Lacroix, Damien

    2011-01-01

    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

  11. 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.

  12. Human cartilage endplate permeability varies with degeneration and intervertebral disc site.

    PubMed

    DeLucca, John F; Cortes, Daniel H; Jacobs, Nathan T; Vresilovic, Edward J; Duncan, Randall L; Elliott, Dawn M

    2016-02-29

    Despite the critical functions the human cartilage endplate (CEP) plays in the intervertebral disc, little is known about its structural and mechanical properties and their changes with degeneration. Quantifying these changes with degeneration is important for understanding how the CEP contributes to the function and pathology of the disc. Therefore the objectives of this study were to quantify the effect of disc degeneration on human CEP mechanical properties, determine the influence of superior and inferior disc site on mechanics and composition, and simulate the role of collagen fibers in CEP and disc mechanics using a validated finite element model. Confined compression data and biochemical composition data were used in a biphasic-swelling model to calculate compressive extrafibrillar elastic and permeability properties. Tensile properties were obtained by applying published tensile test data to an ellipsoidal fiber distribution. Results showed that with degeneration CEP permeability decreased 50-60% suggesting that transport is inhibited in the degenerate disc. CEP fibers are organized parallel to the vertebrae and nucleus pulposus and may contribute to large shear strains (0.1-0.2) and delamination failure of the CEP commonly seen in herniated disc tissue. Fiber-reinforcement also reduces CEP axial strains thereby enhancing fluid flux by a factor of 1.8. Collectively, these results suggest that the structure and mechanics of the CEP may play critical roles in the solute transport and disc mechanics. PMID:26874969

  13. On total disc replacement.

    PubMed

    Berg, Svante

    2011-02-01

    Low back pain consumes a large part of the community's resources dedicated to health care and sick leave. Back disorders also negatively affect the individual leading to pain suffering, decreased quality-of-life and disability. Chronic low back pain (CLBP) due to degenerative disc disease (DDD) is today often treated with fusion when conservative treatment has failed and symptoms are severe. This treatment is as successful as arthroplasty is for hip arthritis in restoring the patient's quality of life and reducing disability. Even so, there are some problems with this treatment, one of these being recurrent CLBP from an adjacent segment (ASD) after primarily successful surgery. This has led to the development of alternative surgical treatments and devices that maintain or restore mobility, in order to reduce the risk for ASD. Of these new devices, the most frequently used are the disc prostheses used in Total Disc Replacement (TDR). This thesis is based on four studies comparing total disc replacement with posterior fusion. The studies are all based on a material of 152 patients with DDD in one or two segments, aged 20-55 years that were randomly treated with either posterior fusion or TDR. The first study concerned clinical outcome and complications. Follow-up was 100% at both one and two years. It revealed that both treatment groups had a clear benefit from treatment and that patients with TDR were better in almost all outcome scores at one-year follow-up. Fusion patients continued to improve during the second year. At two-year follow-up there was a remaining difference in favour of TDR for back pain. 73% in the TDR group and 63% in the fusion group were much better or totally pain-free (n.s.), while twice as many patients in the TDR group were totally pain free (30%) compared to the fusion group (15%). Time of surgery and total time in hospital were shorter in the TDR group. There was no difference in complications and reoperations, except that seventeen of the

  14. Human L3L4 intervertebral disc mean 3D shape, modes of variation, and their relationship to degeneration

    PubMed Central

    Peloquin, John M.; Yoder, Jonathon H.; Jacobs, Nathan T.; Moon, Sung M.; Wright, Alexander C.; Vresilovic, Edward J.; Elliott, Dawn M.

    2014-01-01

    Intervertebral disc mechanics are affected by both disc shape and disc degeneration, which in turn each affect the other; disc mechanics additionally have a role in the etiology of disc degeneration. Finite element analysis (FEA) is a favored tool to investigate these relationships, but limited data for intervertebral disc 3D shape has forced the use of simplified or single-subject geometries, with the effect of inter-individual shape variation investigated only in specialized studies. Similarly, most data on disc shape variation with degeneration is based on 2D mid-sagittal images, which incompletely define 3D shape changes. Therefore, the objective of this study was to quantify inter-individual disc shape variation in 3D, classify this variation into independently-occurring modes using a statistical shape model, and identify correlations between disc shape and degeneration. Three-dimensional disc shapes were obtained from MRI of 13 human male cadaver L3L4 discs. An average disc shape and four major modes of shape variation (representing 90% of the variance) were identified. The first mode represented disc axial area and was significantly correlated to degeneration (R2 = 0.44), indicating larger axial area in degenerate discs. Disc height variation occurred in three distinct modes, each also involving non-height variation. The statistical shape model provides an average L3L4 disc shape for FEA that is fully defined in 3D, and makes it convenient to generate a set of shapes with which to represent aggregate inter-individual variation. Degeneration grade-specific shapes can also be generated. To facilitate application, the model is included in this paper’s supplemental content. PMID:24792581

  15. 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.

  16. 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

  17. 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)

  18. 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…

  19. The Formation and Fragmentation of Primordial Protostellar Discs

    NASA Astrophysics Data System (ADS)

    Clark, Paul C.; Glover, Simon C. O.; Smith, Rowan J.; Greif, Thomas H.; Klessen, Ralf S.; Bromm, Volker

    2010-11-01

    We study the formation and evolution of the protostellar discs that form around the first stars in the Universe. Using sink particles, we replace the gravitationally bound gas at densities higher than 1015 cm-3 and radii greater than 3 AU from the central protostellar core, with an accreting point mass that is able to gravitationally interact with the surrounding gas. We find the disc is gravitationally (or `Toomre') unstable, and is dominated by a strong m = 2 spiral mode. Although the angular momentum transport is dominated by a combination of gravitational torques and Reynolds stresses, which are extremely efficient mechanisms, the disc is unable to process the infalling material and grows increasingly gravitationally unstable. During the build-up of the disc, the temperature in the gas is regulated by a combination of H2 line cooling, collision-induced emission and H2 dissociation, which together help to offset heating from the gravitational collapse and feedback from the protostar. Once the disc starts to fragment, H2 dissociation keeps the gas almost isothermal as the collapse of the fragment progresses. The fragmentation occurs when the protostar/disc system is only 230 yr old and at a distance of ~20 AU from its sibling, by which point the central protostar has a mass of ~1 Msolar. Given the angular momentum of the new protostellar system, it is likely that the protostars will grow to become a massive binary system.

  20. 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.

  1. [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. PMID:3681005

  2. Clinical comparison of St. Jude and porcine mitral valve prostheses.

    PubMed

    Douglas, P S; Hirshfeld, J W; Edie, R N; Stephenson, L W; Gleason, K; Edmunds, L H

    1988-01-01

    One hundred and six consecutive patients who had mitral valve replacement with either a St. Jude or porcine heterograft prosthesis were prospectively studied. The 2 groups are similar with respect to 67 clinical and operative factors and allow comparison of valve performance as an independent variable. Total follow-up is 3,312 patient-months (mean 36 months, range 2-57 months, 94% complete). There are no statistical differences in symptomatic improvement or mortality by life table analysis. Valve-related complications expressed as percent per patient-year are: reoperation: 1.8 St. Jude and 3.8 porcine; endocarditis: 1.2 and 1.9; regurgitant murmur: 2.3 and 1.9; hemolysis: 1.8 and 0.0; late thromboembolism: 1.8 and 1.0; hemorrhage: 2.9 and 2.9; and valve failure: 0.0 and 1.0. There were no significant differences found. Actuarial survival at 3 years was 78% in St. Jude and 81% in porcine patients. Forty-six percent of patients with St. Jude valves and 55% of patients with porcine valves were alive and free of all complications at latest follow-up. The clinical performance of St. Jude and porcine mitral valves are similar over this period of intermediate follow-up. PMID:3360831

  3. 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.

  4. 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.

  5. Electrophysiological analysis of mitral cells in the isolated turtle olfactory bulb.

    PubMed

    Mori, K; Nowycky, M C; Shepherd, G M

    1981-05-01

    1. An in vitro preparation of the turtle olfactory bulb has been developed. Electrophysiological properties of mitral cells in the isolated bulb have been analysed with intracellular recordings. 2. Mitral cells have been driven antidromically from the lateral olfactory tract, or activated directly by current injection. Intracellular injections of horseradish peroxidase (HRP) show that turtle mitral cells have long secondary dendrites that extend up to 1800 micrometer from the cell body and reach around half of the bulbar circumference. There are characteristically two primary dendrites, each supplying separate olfactory glomeruli. 3. Using intracellular current pulses, the whole-neurone resistance was found to range from 33 to 107 M omega. The whole-neurone charging transient had a slow time course. The membrane time constant was estimated to be 24-93 msec by the methods of Rall. The electrotonic length of the mitral cell equivalent cylinder was estimated by Rall's methods to be 0.9-1.9. 4. The spikes generated by turtle mitral cells were only partially blocked by tetrodotoxin (TTX) in the bathing medium. The TTX-resistant spikes were enhanced in the presence of tetraethylammonium (TEA), and blocked completely by cobalt. 5. The implications of the electrical properties for impulse generation in turtle mitral cells are discussed. The mitral cells have dendrodendritic synapses onto granule cells, and the TTX-resistant spikes may therefore play an important role in presynaptic transmitter release at these synapses. PMID:7310692

  6. 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

  7. 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%.

  8. 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

  9. 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.

  10. Nectin-1 spots regulate the branching of olfactory mitral cell dendrites.

    PubMed

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

    2015-09-01

    Olfactory mitral cells extend lateral secondary dendrites that contact the lateral secondary and apical primary dendrites of other mitral cells in the external plexiform layer (EPL) of the olfactory bulb. The lateral dendrites further contact granule cell dendrites, forming dendrodendritic reciprocal synapses in the EPL. These dendritic structures are critical for odor information processing, but it remains unknown how they are formed. We recently showed that the immunoglobulin-like cell adhesion molecule nectin-1 constitutes a novel adhesion apparatus at the contacts between mitral cell lateral dendrites, between mitral cell lateral and apical dendrites, and between mitral cell lateral dendrites and granule cell dendritic spine necks in the deep sub-lamina of the EPL of the developing mouse olfactory bulb and named them nectin-1 spots. We investigated here the role of the nectin-1 spots in the formation of dendritic structures in the EPL of the mouse olfactory bulb. We showed that in cultured nectin-1-knockout mitral cells, the number of branching points of mitral cell dendrites was reduced compared to that in the control cells. In the deep sub-lamina of the EPL in the nectin-1-knockout olfactory bulb, the number of branching points of mitral cell lateral dendrites and the number of dendrodendritic reciprocal synapses were reduced compared to those in the control olfactory bulb. These results indicate that the nectin-1 spots regulate the branching of mitral cell dendrites in the deep sub-lamina of the EPL and suggest that the nectin-1 spots are required for odor information processing in the olfactory bulb. PMID:26169026

  11. Effect of physiological overload on pregnancy in women with mitral regurgitation

    PubMed Central

    Borges, Vera T M; Matsubara, Beatriz B; Magalhães, Claudia G; Peraçoli, Jose C; Rudge, Marilza V C

    2011-01-01

    OBJECTIVES: to evaluate the structural and functional heart abnormalities in women with mitral regurgitation during pregnancy. INTRODUCTION: Women with mitral regurgitation progress well during pregnancy. However, the effects on the heart of the association between pregnancy and mitral regurgitation are not well established. METHODS: This is a case–control, longitudinal prospective study. Echocardiograms were performed in 18 women with mitral regurgitation at the 12th and 36th week of pregnancy and on the 45th day of the puerperium. Twelve age‐matched healthy and pregnant women were included as controls and underwent the same evaluation as the study group. RESULTS: Compared with controls, women with mitral regurgitation presented increased left cardiac chambers in all evaluations. Increasing left atrium during pregnancy occurred only in the mitral regurgitation group. At the end of the puerperium, women with mitral regurgitation showed persistent enlargement of the left atrium compared with the beginning of pregnancy (5.0 ± 1.1 cm vs 4.6 ± 0.9 cm; p<0.05). Reduced left ventricular relative wall thickness (0.13 ± 0.02 vs 0.16 ± 0.02; p<0.05) and an increased peak of afterload (278 ± 55 g/cm2 vs 207 ± 28 g/cm2; p<0.05) was still observed on the 45th day after delivery in the mitral regurgitation group compared with controls. CONCLUSIONS: Pregnancy causes unfavorable structural alterations in women with mitral regurgitation that are associated with an aggravation of the hemodynamic overload. PMID:21437435

  12. Disc piezoelectric ceramic transformers.

    PubMed

    Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

    2013-08-01

    In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power. PMID:25004532

  13. 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

  14. A Review of Animal Models of Intervertebral Disc Degeneration: Pathophysiology, Regeneration, and Translation to the Clinic.

    PubMed

    Daly, Chris; Ghosh, Peter; Jenkin, Graham; Oehme, David; Goldschlager, Tony

    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

  15. Transatrial antegrade approach for double mitral and tricuspid "valve-in-ring" implantation.

    PubMed

    Mazzitelli, Domenico; Bleiziffer, Sabine; Noebauer, Christian; Ruge, Hendrik; Mayr, Patrick; Opitz, Anke; Tassani-Prell, Peter; Schreiber, Christian; Piazza, Nicolo; Lange, Ruediger

    2013-01-01

    Within the last 5 years, the number of transcatheter aortic valve implantation (TAVI) procedures has increased continuously and, in parallel, the indications for TAVI have expanded (eg, failing surgical valves and rings). Furthermore, alternative TAVI access routes such as transaxillary and transaortic have been applied successfully. We report on, to our knowledge, the first-in-human case of a combined off-pump antegrade transatrial implantation of a transcatheter valve within a mitral and tricuspid annuloplasty ring through an anterolateral minithoracotomy. The patient showed severe mitral valve and tricuspid valve stenosis and regurgitation 15 years after mitral valve repair and 7 years after aortic valve replacement and tricuspid valve repair. PMID:23272889

  16. Dynamic simulation of chorded mitral valve in a left ventricle using an immersed boundary method

    NASA Astrophysics Data System (ADS)

    Luo, Xiaoyu; Yin, Min; Liang, Chunlei; Wang, Tiejun; Watton, Paul

    2007-11-01

    We use an immersed boundary model to investigate the dynamic behaviour of a chorded mitral prosthesis placed within a left ventricle under physiological flow conditions. In vivo magnetic resonance images of the left ventricle are used to create a numerical ventricle model. The motion of the ventricle model is prescribed during a cardiac cycle. Fluid-structure interaction simulations are carried out to test the performance of the mitral valve in a more realistic physiological environment. These simulations enable us to assess the effect of the ventricle motion, especially its flow vortex structure, on the function of the chorded mitral valve.

  17. Prevalence of mitral valve prolapse in primary fibromyalgia: a pilot investigation.

    PubMed

    Pellegrino, M J; Van Fossen, D; Gordon, C; Ryan, J M; Waylonis, G W

    1989-07-01

    Fifty patients with primary fibromyalgia and a negative cardiovascular symptom history underwent echocardiography to determine the prevalence of mitral valve prolapse (MVP). The mean age of the population was 40 +/- 13 years (14 men, 36 women). Mitral valve prolapse was detected in 75%; 33% with myxomatous mitral valve leaflets. The prevalence of MVP in this population is significantly higher (p less than 0.0001) than in the general population. Primary fibromyalgia and MVP may be part of a more generalized connective tissue abnormality characterized by distinct genetically determined variants. PMID:2742471

  18. Progressive Mitral Stenosis After MitraClip Implantation in a Patient With Systemic Inflammatory Disease.

    PubMed

    Saji, Mike; Ailawadi, Gorav; Fowler, Dale E; LaPar, Damien J; Dent, John M; Ragosta, Michael; Lim, D Scott

    2016-08-01

    We describe a patient at high surgical risk who was successfully treated with a MitraClip (Abbott Vascular, Menlo Park, CA) without transmitral gradient. She received corticosteroid therapy for systemic lupus erythematosus, and progressive mitral stenosis developed late after MitraClip implantation. It gradually increased and reached 23 mm Hg at 28 months after the procedure; during the same period, her dose of prednisone had to be increased owing to lupus flare. Systemic inflammatory disease has the potential to result in mitral valve inflammation and fibrosis, ultimately causing thickening of the tissue bridge and worsening of the mitral valve obstruction. Preprocedural counseling regarding durability may help in this population. PMID:27449466

  19. Cardiac resynchronisation therapy after percutaneous trans-coronary-venous mitral annuloplasty.

    PubMed

    Siminiak, Tomasz; Jerzykowska, Olga; Kalmucki, Piotr; Link, Rafał; Baszko, Artur

    2013-01-01

    We present a case of a 45-year-old man with symptomatic heart failure and ischaemic functional mitral regurgitation (FMR), who underwent a successful percutaneous trans-coronary venous mitral annuloplasty with the Carillon system. The procedure resulted in clinical improvement as well as in a decrease in the degree of MR as assessed by echocardiography. Fifteen months later, the patient underwent cardiac resynchronisation (CRT) device implantation, resulting in a further improvement in echocardiographic measures of FMR. This case not only confirms the feasibility of CRT after percutaneous trans-coronary-venous mitral annuloplasty, but also suggests a possible synergistic effect of both therapies, warranting future clinical trials. PMID:24399586

  20. Transcatheter Aortic and Mitral Valve Implantation (TAMVI) in Native Rheumatic Valves.

    PubMed

    Akujuo, Adanna C; Dellis, Sophia L; Britton, Lewis W; Bennett, Edward V

    2015-11-01

    A 68-year-old female with moderate to severe aortic stenosis and severe mitral stenosis, deemed too high risk for surgery (STS mortality risk = 12.3%) with a porcelain aorta, was successfully treated with a transcatheter aortic and mitral valve implantation (TAMVI) via a transapical approach. A 23 mm Sapien valve (Edwards Lifesciences, Irvine, CA, USA) was placed in the aortic position and a 29 mm inverted Sapien valve (Edwards Lifesciences) in the mitral position. PMID:26347492

  1. MRI Evaluation of Lumbar Disc Degenerative Disease

    PubMed Central

    Patel, Rupal; Mehta, Chetan; Patel, Narrotam

    2015-01-01

    Introduction: Lower back pain secondary to degenerative disc disease is a condition that affects young to middle-aged persons with peak incidence at approximately 40 y. MRI is the standard imaging modality for detecting disc pathology due to its advantage of lack of radiation, multiplanar imaging capability, excellent spinal soft-tissue contrast and precise localization of intervertebral discs changes. Aims and Objective: To evaluate the characterization, extent, and changes associated with the degenerative lumbar disc disease by Magnetic Resonance Imaging. Study Design: Cross-sectional and observational study. Materials and Methods: A total 109 patients of the lumbar disc degeneration with age group between 17 to 80 y were diagnosed & studied on 1.5 Tesla Magnetic Resonance Imaging machine. MRI findings like lumbar lordosis, Schmorl’s nodes, decreased disc height, disc annular tear, disc herniation, disc bulge, disc protrusion and disc extrusion were observed. Narrowing of the spinal canal, lateral recess and neural foramen with compression of nerve roots observed. Ligamentum flavum thickening and facetal arthropathy was observed. Result: Males were more commonly affected in Degenerative Spinal Disease & most of the patients show loss of lumbar lordosis. Decreased disc height was common at L5-S1 level. More than one disc involvement was seen per person. L4 – L5 disc was the most commonly involved. Annular disc tear, disc herniation, disc extrusion, narrowing of spinal canal, narrowing of lateral recess, compression of neural foramen, ligamentum flavum thickening and facetal arthropathy was common at the L4 –L5 disc level. Disc buldge was common at L3 – L4 & L4 – L5 disc level. Posterior osteophytes are common at L3 - L4 & L5 –S1 disc level. L1- L2 disc involvement and spondylolisthesis are less common. Conclusion: Lumbar disc degeneration is the most common cause of low back pain. Plain radiograph can be helpful in visualizing gross anatomic changes in

  2. 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

  3. 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.

  4. Consecutive transcatheter valve-in-valve implantations: the first in the aortic position, the second in the mitral position, in a patient with failing aortic and mitral bioprostheses

    PubMed Central

    Duncan, Alison; Davies, Simon; Rosendahl, Ulrich; Moat, Neil

    2014-01-01

    A 69-year-old man with a failing aortic valve homograft and failing mitral valve xenograft was admitted with an inability to complete full sentences and pulmonary oedema with right ventricular overload. Severe aortic and mitral regurgitation, severe biventricular impairment and pulmonary hypertension were confirmed on transthoracic and transoesophageal echocardiography. An urgent transfemoral valve-in-valve transcatheter valve implantation (TAVI) was performed within the aortic valve homograft with full resolution of aortic regurgitation. Three months later, a semielective trans-apical valve-in-valve procedure was performed in the mitral position, under cardiopulmonary bypass, with full resolution of mitral regurgitation. His exercise tolerance increased from 5 yards to half a mile. This case report summarises a staged double valve-in-valve procedure in a patient who had three previous sternotomies and who had severe heart failure due to failing aortic and mitral bioprostheses. We report two different delivery approaches, using two different transcatheter devices, and describe valve-in-valve techniques, including cardiopulmonary bypass, in the catheter laboratory. PMID:25053698

  5. Effect of obstructive sleep apnea on mitral valve tenting.

    PubMed

    Pressman, Gregg S; Figueredo, Vincent M; Romero-Corral, Abel; Murali, Ganesan; Kotler, Morris N

    2012-04-01

    Obstructive apneas produce high negative intrathoracic pressure that imposes an afterload burden on the left ventricle. Such episodes might produce structural changes in the left ventricle over time. Doppler echocardiograms were obtained within 2 months of attended polysomnography. Patients were grouped according to apnea-hypopnea index (AHI): mild/no obstructive sleep apnea (OSA; AHI <15) and moderate/severe OSA (AHI ≥15). Mitral valve tenting height and area, left ventricular (LV) long and short axes, and LV end-diastolic volume were measured in addition to tissue Doppler parameters. Comparisons of measurements at baseline and follow-up between and within groups were obtained; correlations between absolute changes (Δ) in echocardiographic parameters were also performed. After a mean follow-up of 240 days mitral valve tenting height increased significantly (1.17 ± 0.12 to 1.28 ± 0.17 cm, p = 0.001) in moderate/severe OSA as did tenting area (2.30 ± 0.41 to 2.66 ± 0.60 cm(2), p = 0.0002); Δtenting height correlated with ΔLV end-diastolic volume (rho 0.43, p = 0.01) and Δtenting area (rho 0.35, p = 0.04). In patients with mild/no OSA there was no significant change in tenting height; there was a borderline significant increase in tenting area (2.20 ± 0.44 to 2.31 ± 0.43 cm(2), p = 0.05). Septal tissue Doppler early diastolic wave decreased (8.04 ± 2.49 to 7.10 ± 1.83 cm/s, p = 0.005) in subjects with moderate/severe OSA but not in in those with mild/no OSA. In conclusion, in patients with moderate/severe OSA, mitral valve tenting height and tenting area increase significantly over time. This appears to be related, at least in part, to changes in LV geometry. PMID:22264596

  6. Systematic review of robotic minimally invasive mitral valve surgery

    PubMed Central

    Seco, Michael; Cao, Christopher; Modi, Paul; Bannon, Paul G.; Wilson, Michael K.; Vallely, Michael P.; Phan, Kevin; Misfeld, Martin; Mohr, Friedrich

    2013-01-01

    Background Robotic telemanipulators have evolved to assist the challenges of minimally invasive mitral valve surgery (MVS). A systematic review was performed to provide a synopsis of the literature, focusing on clinical outcomes and cost-effectiveness. Method Structured searches of MEDLINE, Embase, and Cochrane databases were performed in August 2013. All original studies except case-reports were included in qualitative review. Studies with ≥50 patients were presented quantitatively. Results After applying inclusion and exclusion criteria to the search results, 27 studies were included in qualitative review, 16 of which had ≥50 patients. All studies were observational in nature, and thus the quality of evidence was rated low to medium. Patients generally had good left ventricular performance, were relatively asymptomatic, and mean patient age ranged from 52.6-58.4 years. Rates of intraoperative outcomes ranged from: 0.0-9.1% for conversion to non-robotic surgery, 106±22 to 188.5±53.8 min for cardiopulmonary bypass (CPB) time and 79±16 to 140±40 min for cross-clamp (XC) time. Rates of short-term postoperative outcomes ranged from: 0.0-3.0% for mortality, 0.0-3.2% for myocardial infarction (MI), 0.0-3.0% for permanent stroke, 1.6-15% for pleural effusion, 0.0-5.0% for reoperations for bleeding, 0.0-0.3% for infection, and 1.1-6% for prolonged ventilation (>48 hours), 1.5-5.4% for early repair failure, 12.3±6.7 to 36.6±24.7 hours for intensive care length of stay, 3.1±0.3 to 6.3±3.9 days for hospital length of stay (HLOS) and 81.7-97.6% had no or trivial mitral regurgitation (MR) before discharge. Conclusions All subtypes of mitral valve prolapse are repairable with robotic techniques. CPB and XC times are long, and novel techniques such as the Cor-Knot, Nitinol clips or running sutures may reduce the time required. The overall rates of early postoperative mortality and morbidity are low. Improvements in postoperative quality of life (QoL) and expeditious

  7. 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. PMID:26453995

  8. DISC1–ATF4 transcriptional repression complex: dual regulation of the cAMP-PDE4 cascade by DISC1

    PubMed Central

    Soda, T; Frank, C; Ishizuka, K; Baccarella, A; Park, Y-U; Flood, Z; Park, S K; Sawa, A; Tsai, L-H

    2013-01-01

    Disrupted-In-Schizophrenia 1 (DISC1), a risk factor for major mental illnesses, has been studied extensively in the context of neurodevelopment. However, the role of DISC1 in neuronal signaling, particularly in conjunction with intracellular cascades that occur in response to dopamine, a neurotransmitter implicated in numerous psychiatric disorders, remains elusive. Previous data suggest that DISC1 interacts with numerous proteins that impact neuronal function, including activating transcription factor 4 (ATF4). In this study, we identify a novel DISC1 and ATF4 binding region in the genomic locus of phosphodiesterase 4D (PDE4D), a gene implicated in psychiatric disorders. We found that the loss of function of either DISC1 or ATF4 increases PDE4D9 transcription, and that the association of DISC1 with the PDE4D9 locus requires ATF4. We also show that PDE4D9 is increased by D1-type dopamine receptor dopaminergic stimulation. We demonstrate that the mechanism for this increase is due to DISC1 dissociation from the PDE4D locus in mouse brain. We further characterize the interaction of DISC1 with ATF4 to show that it is regulated via protein kinase A-mediated phosphorylation of DISC1 serine-58. Our results suggest that the release of DISC1-mediated transcriptional repression of PDE4D9 acts as feedback inhibition to regulate dopaminergic signaling. Furthermore, as DISC1 loss-of-function leads to a specific increase in PDE4D9, PDE4D9 itself may represent an attractive target for therapeutic approaches in psychiatric disorders. PMID:23587879

  9. 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

  10. [Coronary sinus devices for treatment of functional mitral valve regurgitation. Solution or dead end?].

    PubMed

    Degen, H; Schneider, T; Wilke, J; Haude, M

    2013-08-01

    In this article we review the currently available data on percutaneous mitral valve annulorrhaphy devices using the coronary sinus in patients with functional mitral valve regurgitation (MR). Of these devices the greatest clinical experience exists for the Carillon mitral contour system which has gained increasing application also outside trials in the last 2 years. The advantages include the ease of use with an effective reduction in functional MR and a subsequent improvement of echocardiographic and clinical parameters. A limitation is the compromise of flow in the circumflex artery in some patients especially with a crossing of the coronary sinus with this artery. Future investigations need to focus on the evaluation of this coronary sinus-based technology versus mitral valve clipping technology for the treatment of functional MR. PMID:23836012

  11. [Spontaneous compensation of severe mitral insufficiency secondary to rupture of chordae tendineae in an athlete].

    PubMed

    Ordzhonikidze, Z G; Pavlov, V I; Mazxerkina, I A; Druzhinin, A E

    2007-01-01

    The article describes an observation of spontaneous compensation of severe mitral insufficiency due to chordal avulsion in a 52-year-old sportsman adapted to hard physical load. After a physical load, the sportsman developed symptoms of acute mitral insufficiency. EchoCG revealed myxomatous degeneration of mitral cusps, chordal avulsion, severe mitral insufficiency, and volume overload of the left heart. The patient refused surgical treatment; conservative therapy was conducted. A three-year follow-up revealed an unexpectedly fast decrease in the size of heart cavities and the speed of regurgitation. The authors reckon that the these fast changes took place due to the sportsmen's heart adaptation to volume overload. PMID:17564044

  12. [Accessory mitral tissue responsible for left ventricular outflow obstruction. Reports of 7 cases].

    PubMed

    Arnaud-Crozat, E; Nottin, R; Chambran, P; Serraf, A; Verrier, J F; Detroux, M; Lacour-Gayet, F; Planche, C; Langlois, J; Binet, J P

    1990-09-01

    The authors report the medico-surgical experience of Marie Lannelongue hospital of a rare condition: accessory mitral valve tissue. Seven patients aged 2 to 28 years (average: 8.7 years) had left ventricular outflow obstruction due to accessory mitral valve tissue. The diagnostic was not obvious clinically and was based on the association of echocardiographic and angiographic data. This condition was associated with another intra-cardiac malformation in 6 of the 7 patients. Surgical treatment included resection of the accessory mitral valve tissue by an aortic or combined aorto-left atrial approach, together with correction of the associated intracardiac abnormality. The postoperative results were excellent with the regression of the ventriculo-aortic pressure gradient and the physiological integrity of the mitral valve. PMID:2122834

  13. Perioperative management of patient with Bombay blood group undergoing mitral valve replacement.

    PubMed

    Priye, Shio; Sathyanarayan, J; Shivaprakash, S; Reddy, Durgaprasad

    2015-12-01

    Bombay red blood cell phenotype is an extremely rare blood type for which patients can receive only autologous or Bombay phenotype red blood cells. We report a case of stenotic mitral valve with Bombay phenotype who underwent minimal invasive right lateral thoracotomy for the replacement of the mitral valve. A male patient from Bangladesh presented to the hospital with New York Heart Association III symptoms. His medical evaluation revealed severe mitral valve stenosis and mild aortic valve regurgitation. The patient received erythropoietin, intravenous iron succinate and folic acid tablets. Autologous blood transfusion was carried out. The mitral valve was replaced with a prosthetic valve successfully. After weaning off from cardiopulmonary bypass, heparinisation was corrected with protamine. Post-operatively, the patient received autologous red blood cells. The patient recovered after 1-day of inotropic support with adrenaline and milrinone, and diuretics and was discharged on the 5(th) post-operative day. PMID:26903676

  14. Perioperative management of patient with Bombay blood group undergoing mitral valve replacement

    PubMed Central

    Priye, Shio; Sathyanarayan, J; Shivaprakash, S; Reddy, Durgaprasad

    2015-01-01

    Bombay red blood cell phenotype is an extremely rare blood type for which patients can receive only autologous or Bombay phenotype red blood cells. We report a case of stenotic mitral valve with Bombay phenotype who underwent minimal invasive right lateral thoracotomy for the replacement of the mitral valve. A male patient from Bangladesh presented to the hospital with New York Heart Association III symptoms. His medical evaluation revealed severe mitral valve stenosis and mild aortic valve regurgitation. The patient received erythropoietin, intravenous iron succinate and folic acid tablets. Autologous blood transfusion was carried out. The mitral valve was replaced with a prosthetic valve successfully. After weaning off from cardiopulmonary bypass, heparinisation was corrected with protamine. Post-operatively, the patient received autologous red blood cells. The patient recovered after 1-day of inotropic support with adrenaline and milrinone, and diuretics and was discharged on the 5th post-operative day. PMID:26903676

  15. Isolated parachute mitral valve in a 29 years old female; a case report.

    PubMed

    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

  16. 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

  17. Chondrule transport in protoplanetary discs

    NASA Astrophysics Data System (ADS)

    Goldberg, Aaron Z.; Owen, James E.; Jacquet, Emmanuel

    2015-10-01

    Chondrule formation remains one of the most elusive early Solar system events. Here, we take the novel approach of employing numerical simulations to investigate chondrule origin beyond purely cosmochemical methods. We model the transport of generically produced chondrules and dust in a 1D viscous protoplanetary disc model in order to constrain the chondrule formation events. For a single formation event we are able to match analytical predictions of the memory they retain of each other (complementarity), finding that a large mass accretion rate (≳10-7 M⊙ yr-1) allows for delays on the order of the disc's viscous time-scale between chondrule formation and chondrite accretion. Further, we find older discs to be severely diminished of chondrules, with accretion rates ≲10-9 M⊙ yr-1 for nominal parameters. We then characterize the distribution of chondrule origins in both space and time, as functions of disc parameters and chondrule formation rates, in runs with continuous chondrule formation and both static and evolving discs. Our data suggest that these can account for the observed diversity between distinct chondrite classes, if some diversity in accretion time is allowed for.

  18. 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.

  19. An Analysis of Burst Disc Pressure Instability

    SciTech Connect

    S. L. Robinson; B. C. Odegard, Jr.; N. r. Moody; S. H. Goods

    2000-06-01

    During the development stage of the 1X Acorn burst disc, burst pressure test results exhibited an unexpected increase of 8 to 14% over times of 90--100 days from initial fabrication. This increase is a concern where design constraints require stability. The disc material, 316L stainless steel sheet, is formed to a dome-like geometry and scored to produce a thin-walled, high-strength ligament. The fracture events controlling burst occur in that ligament. Thus it has been characterized both for tensile properties and microstructure through nanoindentation, magnetic measurements, optical and transmission electron microscopy. These results compare favorably with finite element simulation of the properties of the ligament. The ligament exhibits a highly heterogeneous microstructure; its small volume and microstructural heterogeneity make it difficult to identify which microstructural feature controls fracture and hence burst pressure. Bulk mechanical test specimens were fabricated to emulate mid-ligament properties, and aged at both room and elevated temperatures to characterize and accelerate the temporal behavior of the burst disc. Property changes included yield and ultimate tensile strength increases, and fracture strain decreases with aging. Specimens were subjected to a reversion anneal identical to that given the burst disc to eliminate the martensite phase formed during rolling. Reversion-annealed samples exhibited no change in properties in room temperature or accelerated aging, showing that the reversion-anneal eliminated the aging phenomenon. Aging was analyzed in terms of diffusion controlled precipitate growth kinetics, showing that carbon migration to dislocations is consistent with the strength increases. A vacancy-assisted diffusion mechanism for carbon transport is proposed, giving rise to rapid aging, which replaces interstitial carbon diffusion until excess vacancies from deformation are consumed. Mechanical activation parameters in stress relaxation

  20. Clinical Implications of Preserving Subvalvular Apparatus During Mitral Valve Replacement for Acute Ischemic Papillary Muscle Rupture.

    PubMed

    de Cannière, Didier; Vandenbossche, Jean-Luc; Nouar, Elias; Faict, Sebastian; Falchetti, Alessandro; Unger, Philippe

    2016-07-01

    We report the case of a patient who presented with sequential rupture of two papillary muscle bellies after emergent mitral valve replacement with subvalvular apparatus preservation for acute severe mitral regurgitation and cardiogenic shock during acute myocardial infarction. We discuss the possibility that the remaining chordae may have meanwhile contributed to muscle avulsion by exerting traction on ischemic myocardium and prevented embolization of the secondarily detached papillary muscle heads. PMID:27343501

  1. FLUID-STRUCTURE INTERACTION MODELS OF THE MITRAL VALVE: FUNCTION IN NORMAL AND PATHOLOGIC STATES

    SciTech Connect

    Kunzelman, K. S.; Einstein, Daniel R.; Cochran, R. P.

    2007-08-29

    Successful mitral valve repair is dependent upon a full understanding of normal and abnormal mitral valve anatomy and function. Computational analysis is one such method that can be applied to simulate mitral valve function in order to analyze the roles of individual components, and evaluate proposed surgical repair. We developed the first three-dimensional, finite element (FE) computer model of the mitral valve including leaflets and chordae tendineae, however, one critical aspect that has been missing until the last few years was the evaluation of fluid flow, as coupled to the function of the mitral valve structure. We present here our latest results for normal function and specific pathologic changes using a fluid-structure interaction (FSI) model. Normal valve function was first assessed, followed by pathologic material changes in collagen fiber volume fraction, fiber stiffness, fiber splay, and isotropic stiffness. Leaflet and chordal stress and strain, and papillary muscle force was determined. In addition, transmitral flow, time to leaflet closure, and heart valve sound were assessed. Model predictions in the normal state agreed well with a wide range of available in-vivo and in-vitro data. Further, pathologic material changes that preserved the anisotropy of the valve leaflets were found to preserve valve function. By contrast, material changes that altered the anisotropy of the valve were found to profoundly alter valve function. The addition of blood flow and an experimentally driven microstructural description of mitral tissue represent significant advances in computational studies of the mitral valve, which allow further insight to be gained. This work is another building block in the foundation of a computational framework to aid in the refinement and development of a truly noninvasive diagnostic evaluation of the mitral valve. Ultimately, it represents the basis for simulation of surgical repair of pathologic valves in a clinical and educational

  2. [Intracardiac mass: Why not a liquefaction necrosis of a mitral annulus calcification?].

    PubMed

    Leddet, P; Couppié, P; De Poli, F; Uhry, S; Hanssen, M

    2015-11-01

    We report the case of an asymptomatic 70-year-old woman with a liquefaction necrosis of mitral annulus calcification. This mass was discovered incidentally during an echocardiographic examination. Additional treatment was not performed because liquefaction necrosis of mitral calcification usually has a benign prognosic. A scheduled clinical review with an echocardiographic examination and cardiac MRI was planified. The patient is actually healthy without any complication. PMID:26482628

  3. TAVI in the case of preexisting mitral prosthesis: tips & tricks and literature review.

    PubMed

    Vavuranakis, Manolis; Vrachatis, Dimitrios A; Kariori, Maria G; Moldovan, Carmen; Kalogeras, Konstantinos; Lavda, Maria; Aznaouridis, Konstantinos; Stefanadis, Christodoulos

    2014-11-01

    Very limited data exist on transcatheter aortic valve implantation (TAVI) in the setting of a preexisting mitral prosthesis regarding the technique, potential complications, and outcomes. Here, we report two cases of transfemoral TAVI with a self-expanding bioprosthesis (CoreValve; Medtronic, Inc) in patients who had previously undergone mitral valve replacement (one with an Omniscience and one with a St. Jude prosthesis). A brief literature review is also presented. PMID:25364003

  4. [Mitral stenosis and partial abnormal pulmonary venous return. 3 case reports].

    PubMed

    Pony, J C; Rouxel, P; Logeais, Y; Daubert, J C; Kerdiles, Y; Gouffault, J

    1976-11-01

    The association of mitral stenosis with an abnormal pulmonary venous return in the absence of an atrial septal defect, is a rare occurrence, and three cases are reported here. If this diagnosis is suggested by the chest Xray, it is confirmed by haemodynamic investigation, which defines the abnormal pulmonary drainage, guages the size of the left-right shunt, and demonstrates the degree of mitral steonsis. If the defect is poorly tolerated, surgical treatment is required. PMID:827255

  5. Percutaneous balloon mitral valvuloplasty with bilateral carotid protection in 2 cases of left atrial thrombus.

    PubMed

    Bansal, N O; Duggal, Bhanu; Omnath, R

    2010-01-01

    We present 2 cases of mitral stenosis with left atrial thrombus who underwent Balloon Mitral Valvotomy with bilateral carotid protection using SpiderFX, distal protection devices to minimize the risk of neuroembolic stroke. One patient was critical MS in congestive heart failure with a highly mobile left atrial appendage clot (LAA) and the second patient was a young female who declined surgery and had an LAA clot which did not respond to warfarin therapy. PMID:21180315

  6. Dynamic heart phantom with functional mitral and aortic valves

    NASA Astrophysics Data System (ADS)

    Vannelli, Claire; Moore, John; McLeod, Jonathan; Ceh, Dennis; Peters, Terry

    2015-03-01

    Cardiac valvular stenosis, prolapse and regurgitation are increasingly common conditions, particularly in an elderly population with limited potential for on-pump cardiac surgery. NeoChord©, MitraClipand numerous stent-based transcatheter aortic valve implantation (TAVI) devices provide an alternative to intrusive cardiac operations; performed while the heart is beating, these procedures require surgeons and cardiologists to learn new image-guidance based techniques. Developing these visual aids and protocols is a challenging task that benefits from sophisticated simulators. Existing models lack features needed to simulate off-pump valvular procedures: functional, dynamic valves, apical and vascular access, and user flexibility for different activation patterns such as variable heart rates and rapid pacing. We present a left ventricle phantom with these characteristics. The phantom can be used to simulate valvular repair and replacement procedures with magnetic tracking, augmented reality, fluoroscopy and ultrasound guidance. This tool serves as a platform to develop image-guidance and image processing techniques required for a range of minimally invasive cardiac interventions. The phantom mimics in vivo mitral and aortic valve motion, permitting realistic ultrasound images of these components to be acquired. It also has a physiological realistic left ventricular ejection fraction of 50%. Given its realistic imaging properties and non-biodegradable composition—silicone for tissue, water for blood—the system promises to reduce the number of animal trials required to develop image guidance applications for valvular repair and replacement. The phantom has been used in validation studies for both TAVI image-guidance techniques1, and image-based mitral valve tracking algorithms2.

  7. High Glucose Accelerates Autophagy in Adult Rat Intervertebral Disc Cells

    PubMed Central

    Kong, Chae-Gwan; Kim, Man Soo; Park, Eun-Young

    2014-01-01

    Study Design In vitro cell culture. Purpose The purpose of this study was to investigate the effect of high glucose on autophagy in adult rat intervertebral disc cells. Overview of Literature Diabetes mellitus is considered to be an important etiologic factor for intervertebral disc degeneration, resulting in degenerative disc diseases. A glucose-mediated increase of autophagy is a major causative factor for the development of diseases associated with diabetes mellitus. However, no information is available for the effect of high glucose on autophagy in adult intervertebral disc cells. Methods Nucleus pulposus and annulus fibrosus cells were isolated from 24-week-old adult rats, cultured and placed in either 10% fetal bovine serum (normal control) or 10% fetal bovine serum plus two different high glucose concentrations (0.1 M and 0.2 M) (experimental conditions) for one and three days, respectively. The expressions of autophagy markers, such as beclin-1, light chain 3-I (LC3-I) and LC3-II, autophagy-related gene (Atg) 3, 5, 7 and 12, were identified and quantified. Results Two high glucoses significantly increased the expressions of beclin-1, LC3-II, Atg3, 5, 7, and 12 in adult rat nucleus pulposus and annulus fibrosus cells in a dose- and time-dependent manner. The ratio of LC3-II/LC3-I expression was also increased in a dose-respectively time-dependent manner. Conclusions The results suggest that autophagy of adult nucleus pulposus and annulus fibrosus cells might be a potential mechanism for the intervertebral disc degeneration in adult patients with diabetes mellitus. Thus, the prevention of autophagy in adult intervertebral disc cells might be considered as a novel therapeutic target to prevent or to delay the intervertebral disc degeneration in adult patients with diabetes mellitus. PMID:25346805

  8. Intraoperative measurements on the mitral apparatus using optical tracking: a feasibility study

    NASA Astrophysics Data System (ADS)

    Engelhardt, Sandy; De Simone, Raffaele; Wald, Diana; Zimmermann, Norbert; Al Maisary, Sameer; Beller, Carsten J.; Karck, Matthias; Meinzer, Hans-Peter; Wolf, Ivo

    2014-03-01

    Mitral valve reconstruction is a widespread surgical method to repair incompetent mitral valves. During reconstructive surgery the judgement of mitral valve geometry and subvalvular apparatus is mandatory in order to choose for the appropriate repair strategy. To date, intraoperative analysis of mitral valve is merely based on visual assessment and inaccurate sizer devices, which do not allow for any accurate and standardized measurement of the complex three-dimensional anatomy. We propose a new intraoperative computer-assisted method for mitral valve measurements using a pointing instrument together with an optical tracking system. Sixteen anatomical points were defined on the mitral apparatus. The feasibility and the reproducibility of the measurements have been tested on a rapid prototyping (RP) heart model and a freshly exercised porcine heart. Four heart surgeons repeated the measurements three times on each heart. Morphologically important distances between the measured points are calculated. We achieved an interexpert variability mean of 2.28 +/- 1:13 mm for the 3D-printed heart and 2.45 +/- 0:75 mm for the porcine heart. The overall time to perform a complete measurement is 1-2 minutes, which makes the method viable for virtual annuloplasty during an intervention.

  9. Odour discrimination in the olfactory bulb of goldfish: contrasting interactions between mitral cells and ruffed cells.

    PubMed

    Zippel, H P; Gloger, M; Nasser, S; Wilcke, S

    2000-09-29

    Anatomical differences characterizing mitral cells and ruffed cells have been published by T. Kosaka and K. Hama in three teleost species. Physiological responses from both types of relay neurons were recorded extracellularly and simultaneously in the plexiform layer, using a single tungsten microelectrode. During interstimulus intervals mitral cells responded with higher, frequently burst-like impulse rates triggered by the activity of epithelial receptor neurons. Mitral cell activity could be totally suppressed by local anaesthesia of the olfactory epithelium. Ruffed cell impulse rates were low, and each action potential triggered a long-lasting (3-5 ms), continuously varying, summed granule cell potential. During olfactory stimulation with non-familiar stimuli and important biological stimuli such as amino acids, preovulatory and ovulatory pheromones, and a probable alarm pheromone, contrasting interactions between mitral cells and ruffed cells were recorded frequently, which resulted in a drastic intensification of centrally transmitted information. An excitation of mitral cells' activity via granule cells laterally inhibited the ruffed cells' activity, and an inhibition of mitral cells' activity simultaneously 'released' an excitation of ruffed cells. PMID:11079404

  10. 3D reconstruction and quantitative assessment method of mitral eccentric regurgitation from color Doppler echocardiography

    NASA Astrophysics Data System (ADS)

    Liu, Qi; Ge, Yi Nan; Wang, Tian Fu; Zheng, Chang Qiong; Zheng, Yi

    2005-10-01

    Based on the two-dimensional color Doppler image in this article, multilane transesophageal rotational scanning method is used to acquire original Doppler echocardiography while echocardiogram is recorded synchronously. After filtering and interpolation, the surface rendering and volume rendering methods are performed. Through analyzing the color-bar information and the color Doppler flow image's superposition principle, the grayscale mitral anatomical structure and color-coded regurgitation velocity parameter were separated from color Doppler flow images, three-dimensional reconstruction of mitral structure and regurgitation velocity distribution was implemented separately, fusion visualization of the reconstructed regurgitation velocity distribution parameter with its corresponding 3D mitral anatomical structures was realized, which can be used in observing the position, phase, direction and measuring the jet length, area, volume, space distribution and severity level of the mitral regurgitation. In addition, in patients with eccentric mitral regurgitation, this new modality overcomes the inherent limitations of two-dimensional color Doppler flow image by depicting the full extent of the jet trajectory, the area of eccentric regurgitation on three-dimensional image was much larger than that on two-dimensional image, the area variation tendency and volume variation tendency of regurgitation have been shown in figure at different angle and different systolic phase. The study shows that three-dimensional color Doppler provides quantitative measurements of eccentric mitral regurgitation that are more accurate and reproducible than conventional color Doppler.

  11. An uncommon case of isolated parachute-like asymmetric mitral valve in an adult.

    PubMed

    Mochizuki, Yasuhide; Tanaka, Hidekazu; Fukuda, Yuko; Hirata, Ken-Ichi

    2014-09-01

    A 31-year-old asymptomatic male was referred to hospital for an examination of right bundle brunch block. Both, transthoracic and transesophageal echocardiography revealed normal left ventricular function, and two different-sized papillary muscles; the anterolateral muscle was more pronounced, with almost major chordae tendineae inserted into this dominant muscle, whereas the immature, flat posteromedial papillary muscle had very short chordae tendineae and was located higher in the left ventricle, inserted directly into the mitral annulus. The mitral valve orifice was eccentrically located at the lateral side, but no significant mitral stenosis or regurgitation was observed. No other congenital heart anomalies were identified. Thus, the final diagnosis was isolated parachute-like asymmetric mitral valve (PLAMV), without any other congenital heart anomalies. The patient was followed up closely with periodic echocardiographic examinations. Parachute mitral valve is a rare congenital cardiac defect characterized by focalized attachment of the chordae tendineae of both leaflets to a single papillary muscle. In contrast to true parachute mitral valve, PLAMV has two separate papillary muscles, one of which is more pronounced and into which all chordae are inserted. PLAMV was highly associated with other congenital heart anomalies, and the involved dominant muscle was most frequently a posteromedial papillary muscle. Isolated PLAMV in an adult is even more rare, while the presence of an immature posteromedial papillary muscle--as in the present case--is extremely rare. PMID:25799716

  12. DISC1 regulates trafficking and processing of APP and Aβ generation.

    PubMed

    Shahani, N; Seshadri, S; Jaaro-Peled, H; Ishizuka, K; Hirota-Tsuyada, Y; Wang, Q; Koga, M; Sedlak, T W; Korth, C; Brandon, N J; Kamiya, A; Subramaniam, S; Tomoda, T; Sawa, A

    2015-07-01

    We report the novel regulation of proteolytic processing of amyloid precursor protein (APP) by DISC1, a major risk factor for psychiatric illnesses, such as depression and schizophrenia. RNAi knockdown of DISC1 in mature primary cortical neurons led to a significant increase in the levels of intracellular α-C-terminal fragment of APP (APP-CTFα) and the corresponding N-terminal-secreted ectodomain product sAPPα. DISC1 knockdown also elicited a significant decrease in the levels of amyloid beta (Aβ)42 and Aβ40. These aberrant proteolytic events were successfully rescued by co-expression of wild-type DISC1, but not by mutant DISC1 lacking the amino acids required for the interaction with APP, suggesting that APP-DISC1 protein interactions are crucial for the regulation of the C-terminal proteolysis. In a genetically engineered model in which a major full-length DISC1 isoform is depleted, consistent changes in APP processing were seen: an increase in APP-CTFα and decrease in Aβ42 and Aβ40 levels. Finally, we found that knockdown of DISC1 increased the expression of APP at the cell surface and decreased its internalization. The presented DISC1 mechanism of APP proteolytic processing and Aβ peptide generation, which is central to Alzheimer's disease pathology, suggests a novel interface between neurological and psychiatric conditions. PMID:25224257

  13. Black hole accretion disc impacts

    NASA Astrophysics Data System (ADS)

    Pihajoki, P.

    2016-04-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength λ = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  14. DISC1-dependent Regulation of Mitochondrial Dynamics Controls the Morphogenesis of Complex Neuronal Dendrites*

    PubMed Central

    Norkett, Rosalind; Modi, Souvik; Birsa, Nicol; Atkin, Talia A.; Ivankovic, Davor; Pathania, Manav; Trossbach, Svenja V.; Korth, Carsten; Hirst, Warren D.; Kittler, Josef T.

    2016-01-01

    The DISC1 protein is implicated in major mental illnesses including schizophrenia, depression, bipolar disorder, and autism. Aberrant mitochondrial dynamics are also associated with major mental illness. DISC1 plays a role in mitochondrial transport in neuronal axons, but its effects in dendrites have yet to be studied. Further, the mechanisms of this regulation and its role in neuronal development and brain function are poorly understood. Here we have demonstrated that DISC1 couples to the mitochondrial transport and fusion machinery via interaction with the outer mitochondrial membrane GTPase proteins Miro1 and Miro2, the TRAK1 and TRAK2 mitochondrial trafficking adaptors, and the mitochondrial fusion proteins (mitofusins). Using live cell imaging, we show that disruption of the DISC1-Miro-TRAK complex inhibits mitochondrial transport in neurons. We also show that the fusion protein generated from the originally described DISC1 translocation (DISC1-Boymaw) localizes to the mitochondria, where it similarly disrupts mitochondrial dynamics. We also show by super resolution microscopy that DISC1 is localized to endoplasmic reticulum contact sites and that the DISC1-Boymaw fusion protein decreases the endoplasmic reticulum-mitochondria contact area. Moreover, disruption of mitochondrial dynamics by targeting the DISC1-Miro-TRAK complex or upon expression of the DISC1-Boymaw fusion protein impairs the correct development of neuronal dendrites. Thus, DISC1 acts as an important regulator of mitochondrial dynamics in both axons and dendrites to mediate the transport, fusion, and cross-talk of these organelles, and pathological DISC1 isoforms disrupt this critical function leading to abnormal neuronal development. PMID:26553875

  15. The long-term evolution of photoevaporating transition discs with giant planets

    NASA Astrophysics Data System (ADS)

    Rosotti, Giovanni P.; Ercolano, Barbara; Owen, James E.

    2015-12-01

    Photoevaporation and planet formation have both been proposed as mechanisms responsible for the creation of a transition disc. We have studied their combined effect through a suite of 2D simulations of protoplanetary discs undergoing X-ray photoevaporation with an embedded giant planet. In a previous work, we explored how the formation of a giant planet triggers the dispersal of the inner disc by photoevaporation at earlier times than what would have happened otherwise. This is particularly relevant for the observed transition discs with large holes and high mass accretion rates that cannot be explained by photoevaporation alone. In this work, we significantly expand the parameter space investigated by previous simulations. In addition, the updated model includes thermal sweeping, needed for studying the complete dispersal of the disc. After the removal of the inner disc, the disc is a non-accreting transition disc, an object that is rarely seen in observations. We assess the relative length of this phase, to understand if it is long lived enough to be found observationally. Depending on the parameters, especially on the X-ray luminosity of the star, we find that the fraction of time spent as a non-accretor greatly varies. We build a population synthesis model to compare with observations and find that in general thermal sweeping is not effective enough to destroy the outer disc, leaving many transition discs in a relatively long lived phase with a gas-free hole, at odds with observations. We discuss the implications for transition disc evolution. In particular, we highlight the current lack of explanation for the missing non-accreting transition discs with large holes, which is a serious issue in the planet hypothesis.

  16. DISC1-dependent Regulation of Mitochondrial Dynamics Controls the Morphogenesis of Complex Neuronal Dendrites.

    PubMed

    Norkett, Rosalind; Modi, Souvik; Birsa, Nicol; Atkin, Talia A; Ivankovic, Davor; Pathania, Manav; Trossbach, Svenja V; Korth, Carsten; Hirst, Warren D; Kittler, Josef T

    2016-01-01

    The DISC1 protein is implicated in major mental illnesses including schizophrenia, depression, bipolar disorder, and autism. Aberrant mitochondrial dynamics are also associated with major mental illness. DISC1 plays a role in mitochondrial transport in neuronal axons, but its effects in dendrites have yet to be studied. Further, the mechanisms of this regulation and its role in neuronal development and brain function are poorly understood. Here we have demonstrated that DISC1 couples to the mitochondrial transport and fusion machinery via interaction with the outer mitochondrial membrane GTPase proteins Miro1 and Miro2, the TRAK1 and TRAK2 mitochondrial trafficking adaptors, and the mitochondrial fusion proteins (mitofusins). Using live cell imaging, we show that disruption of the DISC1-Miro-TRAK complex inhibits mitochondrial transport in neurons. We also show that the fusion protein generated from the originally described DISC1 translocation (DISC1-Boymaw) localizes to the mitochondria, where it similarly disrupts mitochondrial dynamics. We also show by super resolution microscopy that DISC1 is localized to endoplasmic reticulum contact sites and that the DISC1-Boymaw fusion protein decreases the endoplasmic reticulum-mitochondria contact area. Moreover, disruption of mitochondrial dynamics by targeting the DISC1-Miro-TRAK complex or upon expression of the DISC1-Boymaw fusion protein impairs the correct development of neuronal dendrites. Thus, DISC1 acts as an important regulator of mitochondrial dynamics in both axons and dendrites to mediate the transport, fusion, and cross-talk of these organelles, and pathological DISC1 isoforms disrupt this critical function leading to abnormal neuronal development. PMID:26553875

  17. Mitral valve repair with artificial chordae: a review of its history, technical details, long-term results, and pathology.

    PubMed

    Bortolotti, Uberto; Milano, Aldo D; Frater, Robert W M

    2012-02-01

    Mitral valve repair is considered the procedure of choice for correcting mitral regurgitation in myxomatous disease, providing long-term results that are superior to those with valve replacement. The use of artificial chordae to replace elongated or ruptured chordae responsible for mitral valve prolapse and severe mitral regurgitation has been the subject of extensive experimental work to define feasibility, reproducibility, and effectiveness of this procedure. Artificial chordae made of autologous or xenograft pericardium have been replaced by chordae made of expanded polytetrafluoroethylene (PTFE), a material with the unique property of becoming covered by host fibrosa and endothelium. The use of artificial chordae made of PTFE has been validated clinically over the past 2 decades and has been an increasing component of the surgical armamentarium for mitral valve repair. This article reviews the history, details of the relevant surgical techniques, long-term results, and fate of artificial chordae in mitral reconstructive surgery. PMID:22153050

  18. Debris disc formation induced by planetary growth

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Löhne, T.

    2014-08-01

    Several hundred stars older than 10 million years have been observed to have infrared excesses. These observations are explained by dust grains formed by the collisional fragmentation of hidden planetesimals. Such dusty planetesimal discs are known as debris discs. In a dynamically cold planetesimal disc, collisional coagulation of planetesimals produces planetary embryos which then stir the surrounding leftover planetesimals. Thus, the collisional fragmentation of planetesimals that results from planet formation forms a debris disc. We aim to determine the properties of the underlying planetesimals in debris discs by numerically modelling the coagulation and fragmentation of planetesimal populations. The brightness and temporal evolution of debris discs depend on the radial distribution of planetesimal discs, the location of their inner and outer edges, their total mass, and the size of planetesimals in the disc. We find that a radially narrow planetesimal disc is most likely to result in a debris disc that can explain the trend of observed infrared excesses of debris discsvvv around G-type stars, for which planet formation occurs only before 100 million years. Early debris disc formation is induced by planet formation, while the later evolution is explained by the collisional decay of leftover planetesimals around planets that have already formed. Planetesimal discs with underlying planetesimals of radii ˜100 km at ≈30 au most readily explain the Spitzer Space Telescope 24 and 70 μm fluxes from debris discs around G-type stars.

  19. 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

  20. Vitreous seeding from a large optic disc melanocytoma.

    PubMed

    Guo, Haoyi; Li, Yujun; Chen, Zhao; Guo, Xirang

    2014-09-01

    We report the case of a 17 year-old man with a large optic disc melanocytoma that underwent spontaneous rupture and seeding of the vitreous with pigmented cells. Potential pathogenic mechanisms and visual prognosis of this rare event are discussed. PMID:24897010