WorldWideScience

Sample records for safety valves

  1. Safety valve for offshore borehole

    Energy Technology Data Exchange (ETDEWEB)

    McGill, H.L.; Randermann, E. Jr.; Musik, O.J.

    1977-10-06

    The invention concerns a new and improved submarine safety valve with a valve element which rotate, which can be used, in emergencies, to separate the wound-up piping which extends into the borehole and to close the production line.

  2. SAFETY SHUTOFF VALVE

    DEFF Research Database (Denmark)

    2010-01-01

    resulted from collision or effusion. A static tower has been applied for the main core of this part of the valve which loses balance state under the effect of collision and bounces to the neighboring part, which results in release of the catch and blockage of the gas passing channel.......It is disclosed a shut-off valve which acts automatically and has a fully mechanical performance with respect to the loosing of the tower-shape part balance under the effect of the special acceleration Which is arisen from the quakes waves or serious vibrations, while such vibrations are mainly...

  3. PUMP ARRANGEMENT COMPRISING A SAFETY VALVE ARRANGEMENT

    OpenAIRE

    Richter, Martin; Wackerle, Martin

    2014-01-01

    A pump arrangement comprises a microfluidic pump (20) having a pump inlet (22) and a pump outlet (24), which is configured to pump a fluid from the pump inlet to the pump outlet, wherein the pump inlet (22) and an inlet (46) of the pump arrangement are fluidically connected. The pump arrangement further comprises a safety valve arrangement having first safety valve (40), the first safety valve (40) being arranged between the pump outlet (24) and an outlet (48) of the pump arrangement and comp...

  4. Potential problems will drillstring safety valves

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    In the paper titled ``New generation drill string safety valves,`` presented at the IADC Well Control Conference for Europe, Aberdeen, May 22--24, 1996, documented limitations of presently available drillstring safety valves commonly used as kelly valves and stabbing valves were presented, and industry efforts to develop solutions to these problems were described. Authors of the paper are B.A. Tarr and R.A. Sukup (Mobil E and P Technology Center, Dallas), Dr. R. Luy (ITE, Clausthal, Germany), G. Rabby (Hi-Kalibre, Edmonton, Alberta) and J. Mertsch (ITAG, Celle, Germany). In 1995, the Task Group developed a draft of a new spec, and a DSSV testing program was initiated as a joint industry project, with the Gas Research Institute (GRI) as the major sponsor. Two manufacturers, Hi-Kalibre and ITAG, agreed to build new valves for the testing program. Hi-Kalibre, Edmonton, Alberta, supplied an already-commercial twin floating ball valve for November 1995 testing. This product is being used by Tesco in its portable top drive system. ITAG of Germany supplied a radically improved DSSV design, which was tested in December, and was to be retested in May following modifications.

  5. 46 CFR 61.05-20 - Boiler safety valves.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Boiler safety valves. 61.05-20 Section 61.05-20 Shipping... INSPECTIONS Tests and Inspections of Boilers § 61.05-20 Boiler safety valves. Each safety valve for a drum, superheater, or reheater of a boiler shall be tested at the interval specified by table 61.05-10. ...

  6. Innovative safety valve selection techniques and data.

    Science.gov (United States)

    Miller, Curt; Bredemyer, Lindsey

    2007-04-11

    The new valve data resources and modeling tools that are available today are instrumental in verifying that that safety levels are being met in both current installations and project designs. If the new ISA 84 functional safety practices are followed closely, good industry validated data used, and a user's maintenance integrity program strictly enforced, plants should feel confident that their design has been quantitatively reinforced. After 2 years of exhaustive reliability studies, there are now techniques and data available to support this safety system component deficiency. Everyone who has gone through the process of safety integrity level (SIL) verification (i.e. reliability math) will appreciate the progress made in this area. The benefits of these advancements are improved safety with lower lifecycle costs such as lower capital investment and/or longer testing intervals. This discussion will start with a review of the different valve, actuator, and solenoid/positioner combinations that can be used and their associated application restraints. Failure rate reliability studies (i.e. FMEDA) and data associated with the final combinations will then discussed. Finally, the impact of the selections on each safety system's SIL verification will be reviewed.

  7. The safety relief valve handbook design and use of process safety valves to ASME and International codes and standards

    CERN Document Server

    Hellemans, Marc

    2009-01-01

    The Safety Valve Handbook is a professional reference for design, process, instrumentation, plant and maintenance engineers who work with fluid flow and transportation systems in the process industries, which covers the chemical, oil and gas, water, paper and pulp, food and bio products and energy sectors. It meets the need of engineers who have responsibilities for specifying, installing, inspecting or maintaining safety valves and flow control systems. It will also be an important reference for process safety and loss prevention engineers, environmental engineers, and plant and process designers who need to understand the operation of safety valves in a wider equipment or plant design context. . No other publication is dedicated to safety valves or to the extensive codes and standards that govern their installation and use. A single source means users save time in searching for specific information about safety valves. . The Safety Valve Handbook contains all of the vital technical and standards informat...

  8. Phase separator safety valve blow-off.

    CERN Multimedia

    G. Perinic

    2006-01-01

    The fast discharge of the CMS solenoid leads to a pressure rise in the phase separator. On August 28th, a fast discharge was triggered at a current level of 19.1 kA. The pressure in the phase separator increased up to the set pressure of the safety valve and some helium was discharged. In consequence of this and prevoious similar observations the liquid helium level in the phase separator has been reduced from 60% to 50% and later to 45% in order to reduce the helium inventory in the magnet.

  9. Pressurizer Heater and Safety Valve Test for SPACE code

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Hyuk; Youn, Bum Soo; Jun, Hwang Yong; Kim, Se Yun; Ha, Sang Jun [KEPCO Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    The Korea nuclear industry has been developing a thermal-hydraulic analysis code for safety analysis of PWR(pressurized water reactor). The new code is named SPACE(Safety and Performance Analysis Code for Nuclear Power Plant). In this paper, the pressurizer heater model and safety valve for SPACE code is tested. The SPACE code input for pressurizer is developed and simulations are performed. Calculations were performed with and without heater and safety valve model and results are compared to confirm effectiveness of heater and safety valve

  10. 75 FR 1276 - Requirements for Subsurface Safety Valve Equipment

    Science.gov (United States)

    2010-01-11

    ... Minerals Management Service 30 CFR Part 250 RIN 1010-AD45 Requirements for Subsurface Safety Valve Equipment AGENCY: Minerals Management Service (MMS), Interior. ACTION: Final rule. SUMMARY: The MMS is... Subsurface Safety Valve Equipment (API Spec 14A) into its regulations. The MMS is incorporating the Eleventh...

  11. Numerical Analysis for Structural Safety Evaluation of Butterfly Valves

    Science.gov (United States)

    Shin, Myung-Seob; Yoon, Joon-Yong; Park, Han-Yung

    2010-06-01

    Butterfly valves are widely used in current industry to control the fluid flow. They are used for both on-off and throttling applications involving large flows at relatively low operating pressure especially in large size pipelines. For the industrial application of butterfly valves, it must be ensured that the valve could be used safety under the fatigue life and the deformations produced by the pressure of the fluid. In this study, we carried out the structure analysis of the body and the valve disc of the butterfly valve and the numerical simulation was performed by using ANSYS v11.0. The reliability of valve is evaluated under the investigation of the deformation, the leak test and the durability of the valve.

  12. The Development of the Code Safety Valve Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Hyun; Kim, Young Ae; Park, Jong Woon [Korea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of)

    2007-07-01

    The Pressurizer Safety Valves (PSV) in Pressurized Water Reactors (PWRs) are required to provide the overpressure protection for the Reactor Coolant System (RCS) during the overpressure transients. According to the ASME OM code, all safety valves should be tested every 5 years with the acceptance tolerance of 1%. If one valve failed to meet this criterion, other two additional valves should be tested and if these valves don't meet the requirement, all valves should be tested. These frequent tests may make the valves decrepit and become a cause of leak. Therefore, increase of the acceptance tolerance is vital for the safe operation of the plant. In the United States, the acceptance tolerances are enlarged up to about 3% in most plants. This requires re-analysis of relevant accidents in FSAR. Also, the technical background data for the valve pop-up characteristics and the loop seal dynamics (if the plant has the loop seal in the upstream of PSV) are needed for the new safety analysis. Korea Hydro and Nuclear Power Company (KHNP) plans to build the PSV test facility for the purpose of providing the background data. This paper describes the preliminary design of the facility and studies on the system dynamics using GOTHIC-7.2a code to verify the pressure vessel capacities and to find the best operating condition.

  13. Safety considerations during transapical aortic valve implantation.

    Science.gov (United States)

    Drews, Thorsten; Pasic, Miralem; Juran, Ralf; Unbehaun, Axel; Dreysse, Stephan; Kukucka, Marian; Mladenow, Alexander; Hetzer, Roland; Buz, Semih

    2014-05-01

    Transcatheter aortic valve implantation (TAVI) is a new method for the treatment of very high-risk patients with aortic valve stenosis. The radiation dose to which the patient and each member of the heart team are exposed during this new fluoroscopically guided intervention is unknown. Between April 2008 and August 2013, 1177 consecutive patients underwent transapical TAVI (TA-TAVI). In 22 consecutive patients undergoing TA-TAVI, the radiation doses to the cardiothoracic surgeon, cardiologist, anaesthesiologist (performing echocardiography examination), surgical assistant and nurse were measured. The radiation dose measurements were performed during TAVI using thermoluminescence and film dosimeters positioned on seven parts of the body: (i) chest above the lead apron, (ii) pelvic area below the apron, (iii) chest below the apron, (iv) thyroid gland above the apron, (v) near eyes, (vi) hands (using rings) and (vii) the feet. The results were compared with the values given in the international literature on recommended radiation dose limits for workers. The mean radiation time was 6.1 min and the mean dose-area product for the patients was 8.661 µGy · m(2). Analysis of the dosimeters and the calculation of the effective dose showed a per intervention dose of 0.03 mSv for the surgeon, 0.05 mSv for the assistant, 0.02 mSv for the cardiologist and the anaesthesiologist and 0.001 mSv for the nurse. The maximum ionizing radiation per intervention was 0.5 mSv at the right hand of the surgeon (holding the introducer sheet) and 0.7 mSv at the left hand of the surgical assistant. Additionally, the analysis of the body dose shows a maximum dose to the lower leg of the surgeon (0.3 mSv) and the genital area of the assistant (0.06 mSv). During a TA-TAVI procedure, the patients receive a higher X-ray dose than during coronary angiography with intervention. After 100 TAVI procedures, the members of the heart team sustain a comparable dose of ionizing radiation to the annual dose

  14. 30 CFR 250.445 - What are the requirements for kelly valves, inside BOPs, and drill-string safety valves?

    Science.gov (United States)

    2010-07-01

    ... motor and use drill pipe instead of a kelly, you must install one kelly valve above, and one strippable kelly valve below, the joint of drill pipe used in place of a kelly; (d) On a top-drive system equipped..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources MINERALS...

  15. 46 CFR 196.30-20 - Breaking of safety valve seal.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Breaking of safety valve seal. 196.30-20 Section 196.30... OPERATIONS Reports of Accidents, Repairs, and Unsafe Equipment § 196.30-20 Breaking of safety valve seal. (a) If at any time it is necessary to break the seal on a safety valve for any purpose, the Chief...

  16. CFD analysis with fluid-structure interaction of opening high-pressure safety valves

    NARCIS (Netherlands)

    Beune, A.; Kuerten, Johannes G.M.; van Heumen, M.P.C.

    2012-01-01

    A multi-mesh numerical valve model has been developed to analyze the opening characteristic of highpressure safety valves. Newton’s law and the CFD result for the flow force are used to model the movement of the valve. In incompressible transient flow simulations a large force rise and collapse is

  17. 46 CFR 52.20-17 - Opening between boiler and safety valve (modifies PFT-44).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Opening between boiler and safety valve (modifies PFT-44). 52.20-17 Section 52.20-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS Requirements for Firetube Boilers § 52.20-17 Opening between boiler and safety valve...

  18. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Safety valve requirements for steam boilers (modifies HG... requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and the safety valve requirements for steam boilers must be as indicated in HG-400 and HG-401 of section IV of...

  19. Study of safety relief valve operation under ATWS conditions. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Hutmacher, E.S.; Nesmith, B.J.; Brukiewa, J.B.

    1979-06-25

    A literature survey and analysis project has been performed to determine if recent (since mid-1975) data has been reported which could influence the current approach to predicting PWR relief valve capacity under ATWS conditions. This study was conducted by the Energy Technology Engineering Center for NRC. Results indicate that the current relief valve capacity model tends to predict less capacity than actually obtains; however, no experimental verification at PWR ATWS conditions was found. Other project objectives were to establish the availability of methods for evaluating reaction forces and back pressure effects on relief valve capacity, and to determine if facilities exist which are capable of testing PWR relief valves at ATWS conditions.

  20. Management of neonatal hydrocephalus: feasibility of use and safety of two programmable (Sophy and Polaris) valves.

    Science.gov (United States)

    Martínez-Lage, Juan F; Almagro, María-José; Del Rincón, Isabel Sanchez; Pérez-Espejo, Miguel A; Piqueras, Claudio; Alfaro, Raúl; Ros de San Pedro, Javier

    2008-05-01

    Neonates represent a unique group of pediatric patients with special peculiarities. Hydrocephalus valves have not always been designed to meet the requirements of these small children. Few series have addressed the problem of cerebrospinal fluid shunting in newborn babies. We aimed (1) to evaluate the feasibility of the use of two programmable valves (Sophy and Polaris) in hydrocephalic neonates and (2) to ascertain complications and safety issues arising from their use. We performed a prospective study of 100 consecutive preterm and term babies (Polaris) can be safely used for treatment of neonatal hydrocephalus, introducing some technical modifications. (2) Both valves are comparable to other shunts with regard to indications, performance, and safety. (3) The possibility of modifying their working pressure seems to constitute their main advantage. Prevention of late overdrainage syndromes with these valves needs a longer follow-up.

  1. Recent performance experience with US light water reactor self-actuating safety and relief valves

    Energy Technology Data Exchange (ETDEWEB)

    Hammer, C.G.

    1996-12-01

    Over the past several years, there have been a number of operating reactor events involving performance of primary and secondary safety and relief valves in U.S. Light Water Reactors. There are several different types of safety and relief valves installed for overpressure protection of various safety systems throughout a typical nuclear power plant. The following discussion is limited to those valves in the reactor coolant systems (RCS) and main steam systems of pressurized water reactors (PWR) and in the RCS of boiling water reactors (BWR), all of which are self-actuating having a setpoint controlled by a spring-loaded disk acting against system fluid pressure. The following discussion relates some of the significant recent experience involving operating reactor events or various testing data. Some of the more unusual and interesting operating events or test data involving some of these designs are included, in addition to some involving a number of similar events and those which have generic applicability.

  2. Direct transcatheter aortic valve implantation with self-expandable bioprosthesis: Feasibility and safety

    Energy Technology Data Exchange (ETDEWEB)

    Fiorina, Claudia, E-mail: clafiorina@yahoo.it [Cardiac Catheterization Laboratory, Cardiothoracic Department, Spedali Civili, Brescia (Italy); Maffeo, Diego; Curello, Salvatore [Cardiac Catheterization Laboratory, Cardiothoracic Department, Spedali Civili, Brescia (Italy); Lipartiti, Felicia [Division of Cardiology, Cardiothoracic Department, Spedali Civili, Brescia (Italy); Chizzola, Giuliano [Cardiac Catheterization Laboratory, Cardiothoracic Department, Spedali Civili, Brescia (Italy); D' Aloia, Antonio [Division of Cardiology, Cardiothoracic Department, Spedali Civili, Brescia (Italy); Adamo, Marianna [Cardiac Catheterization Laboratory, Cardiothoracic Department, Spedali Civili, Brescia (Italy); Mastropierro, Rosy [Division of Cardiothoracic Anestesiology, Cardiothoracic Department, Spedali Civili, Brescia (Italy); Gavazzi, Emanuele [Department of Radiology, University of Brescia, Spedali Civili, Brescia (Italy); Ciccarese, Camilla; Chiari, Ermanna [Division of Cardiology, Cardiothoracic Department, Spedali Civili, Brescia (Italy); Ettori, Federica [Cardiac Catheterization Laboratory, Cardiothoracic Department, Spedali Civili, Brescia (Italy)

    2014-06-15

    Background: Balloon valvuloplasty has been considered a mandatory step of the transcatheter aortic valve implantation (TAVI), although it is not without risk. The aim of this work was to evaluate the feasibility and safety of TAVI performed without pre-dilation (direct TAVI) of the stenosed aortic valve. Material and Methods: Between June 2012 and June 2013, 55 consecutive TAVI performed without pre-dilation at our institution using the self-expandable CoreValve prosthesis (Medtronic, Minneapolis, MN) were analyzed and compared with 45 pre-dilated TAVI performed the previous year. Inclusion criteria were a symptomatic and severe aortic stenosis. Exclusion criteria were defined as presence of pure aortic regurgitation, degenerated surgical bioprosthesis or bicuspid aortic valve and prior procedure of balloon aortic valvuloplasty performed as a bridge to TAVI. Results: High-burden calcification in the device landing zone, assessed by CT scan, was found in most of the patients. The valve size implanted was similar in both groups. Device success was higher in direct TAVI (85% vs. 64%, p = 0.014), mostly driven by a significant lower incidence of paravalvular leak (PVL ≥2; 9% vs. 33%, p = 0.02). Safety combined end point at 30 days was similar in both groups. Conclusion: Compared to TAVI with pre-dilation, direct TAVI is feasible regardless of the presence of bulky calcified aortic valve and the valve size implanted. Device success was higher in direct TAVI, mostly driven by a lower incidence of paravalvular leak. Safety at 30 days was similar in two groups.

  3. Analysis of pressure safety valves for fire protection on offshore oil and gas installations

    DEFF Research Database (Denmark)

    Bjerre, Michael; Eriksen, Jacob G.I.; Andreasen, Anders

    2017-01-01

    The effectiveness of fire Pressure Safety Valves (PSV) has been investigated when offshore process equipment is exposed to a fire. Simulations of several typical offshore pressure vessels have been performed using the commercial software VessFire. The pressure vessels are exposed to a small jet f...

  4. Characterization of Prototype Superfluid Helium Safety Relief Valves for the LHC Magnets

    CERN Document Server

    Dufay, L; Van Weelderen, R

    1999-01-01

    The Large Hadron Collider (LHC) at CERN will use high field superconducting magnets operating in pressurized superfluid helium (He II) at 1.9 K. Cold safety valves, with their inlet in direct contact with the He II bath, will be required to protect the cold masses in case of a magnet resistive transition. In addition to the safety function, the valves must limit their conduction heat load to the He II to below 0.3 W and limit their mass leakage when closed to below 0.01 g/s at 1.9 K with 100 mbar differential pressure. The valves must also have a high tolerance to contaminating particles in the liquid helium. The compliance with the specified performance is of crucial importance for the LHC cryogenic operation. An extensive test program is therefore being carried out on prototype industrial valves produced by four different manufacturers. The behavior of these valves has been investigated at room temperature and at 77 K. Precise heat load and mass leak measurements have been performed on a dedicated test faci...

  5. The safety of tracheostomy speaking valve use during sleep in children: a pilot study.

    Science.gov (United States)

    Barraza, Giselle Y; Fernandez, Claudia; Halaby, Claudia; Ambrosio, Sara; Simpser, Edwin F; Pirzada, Melodi B

    2014-01-01

    One of the disadvantages of having a tracheostomy tube is not being able to vocalize. A speaking valve connected to a tracheostomy tube allows patients to vocalize. Some studies have shown that tracheostomy-speaking valve can improve swallowing, respiratory secretion management, and expedite decannulation. There is scant research about speaking valve use during sleep. The aim of this study is to evaluate the safety of tracheostomy-speaking valve overnight, during sleep. Children, ages 1-18 years, with tracheostomy tubes who were using a tracheostomy-speaking valve during daytime/awake periods, were included in this study. The subjects had baseline monitoring of their heart rate, respiratory rate, oxygen saturation, and end tidal carbon dioxide measurement the night prior to the intervention, throughout the night at scheduled intervals. The tracheostomy-speaking valve was placed the following night and the same parameters were monitored and recorded throughout the study night. A total of 9 patients were recruited. In all subjects, the mean values of the overnight parameters showed no significant clinical variations between the baseline night and the study night. Repeated measure ANOVA analysis revealed no significant changes in the parameters over the 8 hours of recorded time. No major adverse events were recorded during the study night. This pilot study reveals that use of a tracheostomy-speaking valve during sleep, was not associated with adverse cardiopulmonary events. This is the first study to show that a tracheostomy-speaking valve might be safely used during sleep, in children. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Efficacy and safety of the Lotus Valve System for treatment of patients with severe aortic valve stenosis and intermediate surgical risk

    DEFF Research Database (Denmark)

    De Backer, Ole; Götberg, Matthias; Ihlberg, Leo

    2016-01-01

    )-defined device success was obtained in 97.4%. A Lotus Valve was successfully implanted in all patients. There was no valve migration, embolization, ectopic valve deployment, or TAV-in-TAV deployment. The VARC-defined combined safety rate at 30days was 92.2%, with a mortality rate of 1.9% and stroke rate of 3.......9% - this rate was 12.8% in case of a combined implantation depth device/annulus ratiosafety of the repositionable, retrievable Lotus Valve System in intermediate risk patients with AS. The VARC-defined device success rate was 97.......2%. The clinical efficacy rate after 30days was 91.6% - only one patient had moderate aortic regurgitation. When considering only those patients in the late experience group (N=79), the combined safety and clinical efficacy rates were 93.7% and 92.4%, respectively. The pacemaker implantation rate was 27...

  7. The Analysis of Loop Seal Purge Time for the KHNP Pressurizer Safety Valve Test Facility Using the GOTHIC Code

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Ae; Kim, Chang Hyun; Kweon, Gab Joo; Park, Jong Woon [Korea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of)

    2007-10-15

    The pressurizer safety valves (PSV) in Pressurized Water Reactors are required to provide the overpressure protection for the Reactor Coolant System (RCS) during the overpressure transients. Korea Hydro and Nuclear Power Company (KHNP) plans to build the PSV test facility for the purpose of providing the PSV pop-up characteristics and the loop seal dynamics for the new safety analysis. When the pressurizer safety valve is mounted in a loop seal configuration, the valve must initially pass the loop seal water prior to popping open on steam. The loop seal in the upstream of PSV prevents leakage of hydrogen gas or steam through the safety valve seat. This paper studies on the loop seal clearing dynamics using GOTHIC-7.2a code to verify the effects of loop seal purge time on the reactor coolant system overpressure.

  8. SAFETY ALERT - Failure of brass non-return valves in gas point installations

    CERN Multimedia

    HSE Unit

    2016-01-01

    There have been three recent failures in brass non-return valves in separate high pressure gas point installations across CERN. Whilst each was in a different gas service, the visual nature of the failure has been similar.   In all three cases, these components were connected to stainless steel flexible connections and stainless steel pipework. From the metallurgical investigation of the failed component, it appears that the failure is linked to uncontrolled tightening, leading to a localised weakening resulting in premature failure when subjected to pressure. Lead levels in the examined components appear to be a contributing factor to the reduction in ductility but are not identified as the root cause. It has also not been possible to attribute failure to a particular batch of material. The Occupational Health & Safety and Environmental Protection Unit prescribes the following actions to be taken, aligned with the CERN Safety Rules: Verification of all brass non-return valves (prioritising...

  9. Experimental Investigation of Cavitation in a Safety Relief Valve using water. Extension to Cryogenic fluids.

    OpenAIRE

    Pinho, Jorge

    2015-01-01

    This thesis addresses the experimental investigation of the cavitation phenomenon and its main consequences on the normal operation of a safety relief valve (SRV). More particularly, limitation of the mass flux discharged and alteration of the hydraulic fluid forces behavior is of main interest for the proper design and sizing of such devices. In nuclear or thermal engineering systems, the use of SRVs is mandatory since it represents the ultimate protection device before an accident occurs, c...

  10. An Innovative Cryogenic Safety Valve Dimensioner - Kryolize®

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Kryolize is a novel software tool to a harmonized approch for sizing the minimum discharge area of safety devices for cryogenic installations. This talk will give an exclusive glimpse behind the scenes how a standard compliant software containing the latest results of research in the field of cryogenics at CERN can be developed. Starting from a collection of formulas the new software tool needs to fulfill certain requirements to allow a wide dissemination not only across the scientific community but also for the industrial sector, thus providing solid core development as well as a user friendly interface. This includes the optimization of the program flow as well as the development and efficient implementation of sophisticated approximation algorithms for a time saving and effortless user experience.

  11. Structural safety analysis based on seismic service conditions for butterfly valves in a nuclear power plant.

    Science.gov (United States)

    Han, Sang-Uk; Ahn, Dae-Gyun; Lee, Myeong-Gon; Lee, Kwon-Hee; Han, Seung-Ho

    2014-01-01

    The structural integrity of valves that are used to control cooling waters in the primary coolant loop that prevents boiling within the reactor in a nuclear power plant must be capable of withstanding earthquakes or other dangerous situations. In this study, numerical analyses using a finite element method, that is, static and dynamic analyses according to the rigid or flexible characteristics of the dynamic properties of a 200A butterfly valve, were performed according to the KEPIC MFA. An experimental vibration test was also carried out in order to verify the results from the modal analysis, in which a validated finite element model was obtained via a model-updating method that considers changes in the in situ experimental data. By using a validated finite element model, the equivalent static load under SSE conditions stipulated by the KEPIC MFA gave a stress of 135 MPa that occurred at the connections of the stem and body. A larger stress of 183 MPa was induced when we used a CQC method with a design response spectrum that uses 2% damping ratio. These values were lower than the allowable strength of the materials used for manufacturing the butterfly valve, and, therefore, its structural safety met the KEPIC MFA requirements.

  12. Safety and Efficacy of Transcatheter Aortic Valve Replacement in the Treatment of Pure Aortic Regurgitation in Native Valves and Failing Surgical Bioprostheses: Results From an International Registry Study.

    Science.gov (United States)

    Sawaya, Fadi J; Deutsch, Marcus-André; Seiffert, Moritz; Yoon, Sung-Han; Codner, Pablo; Wickramarachchi, Upul; Latib, Azeem; Petronio, A Sonia; Rodés-Cabau, Josep; Taramasso, Maurizio; Spaziano, Marco; Bosmans, Johan; Biasco, Luigi; Mylotte, Darren; Savontaus, Mikko; Gheeraert, Peter; Chan, Jason; Jørgensen, Troels H; Sievert, Horst; Mocetti, Marco; Lefèvre, Thierry; Maisano, Francesco; Mangieri, Antonio; Hildick-Smith, David; Kornowski, Ran; Makkar, Raj; Bleiziffer, Sabine; Søndergaard, Lars; De Backer, Ole

    2017-05-22

    The aim of this study was to evaluate the use of transcatheter heart valves (THV) for the treatment of noncalcific pure native aortic valve regurgitation (NAVR) and failing bioprosthetic surgical heart valves (SHVs) with pure severe aortic regurgitation (AR). Limited data are available about the "off-label" use of transcatheter aortic valve replacement (TAVR) to treat pure severe AR. The study population consisted of patients with pure severe AR treated by TAVR at 18 different centers. Study endpoints were device success, early safety, and clinical efficacy at 30 days, as defined by Valve Academic Research Consortium 2 criteria. A total of 146 patients were included, 78 patients in the NAVR group and 68 patients in the failing SHV group. In the NAVR group, device success, early safety, and clinical efficacy were 72%, 66%, and 61%, respectively. Device success and clinical efficacy were significantly better with newer generation THVs compared with old-generation THVs (85% vs. 54% and 75% vs. 46%, respectively, p 8%, major vascular or access complication, and moderate to severe AR. In the failing SHV group, device success, early safety, and clinical efficacy were 71%, 90%, and 77%, respectively. TAVR for pure NAVR remains a challenging condition, with old-generation THVs being associated with THV embolization and migration and significant paravalvular regurgitation. Newer generation THVs show more promising outcomes. For those patients with severe AR due to failing SHVs, TAVR is a valuable therapeutic option. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. Pilot program to identify valve failures which impact the safety and operation of light water nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Tsacoyeanes, J. C.; Raju, P. P.

    1980-04-01

    The pilot program described has been initiated under the Department of Energy Light Water Reactor Safety Research and Development Program and has the following specific objectives: to identify the principal types and causes of failures in valves, valve operators and their controls and associated hardware, which lead to, or could lead to plant trip; and to suggest possible remedies for the prevention of these failures and recommend future research and development programs which could lead to minimizing these valve failures or mitigating their effect on plant operation. The data surveyed cover incidents reported over the six-year period, beginning 1973 through the end of 1978. Three sources of information on valve failures have been consulted: failure data centers, participating organizations in the nuclear power industry, and technical documents.

  14. 30 CFR 250.807 - Additional requirements for subsurface safety valves and related equipment installed in high...

    Science.gov (United States)

    2010-07-01

    ... valves and related equipment installed in high pressure high temperature (HPHT) environments. 250.807... GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250... pressure high temperature (HPHT) environments. (a) If you plan to install SSSVs and related equipment in an...

  15. The numerical evaluation of the minimal outlet area of the safety valve in the pipelines of cryogenic installations

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The flow of cold helium in pipes is a fundamental issue of any cryogenic installation. Pipelines for helium transportation can reach lengths of hundreds of meters. The proper selection of size for individual pipelines and safety valves is a crucial part in the consideration of costs for the entire installation and its safe operation. The size of the safety valve must be properly designed in order to avoid a dangerous pressure buildup during normal operation, as well as in the case of emergency. The most commonly occurring dangerous situation is an undesired heat flux in the helium as a result of a broken insulation. In this case, the heat flux can be very intense and the buildup of the pressure in the pipe can be very rapid. In the present work, numerical calculations were used to evaluate the buildup of pressure and temperature in the pipe, in the case of a sudden and intense heat flux. The main goal of the applied numerical procedure was to evaluate the proper sizes of the safety valves in order to avoid a...

  16. Analysis of pressure transients in Safety Injection (SI) piping for the opening cause of SKN 3 Safety Relief Valves

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Suk-Ho; Lim, Sang-Gyu; Kim, Han-Gon [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    During preoperation and tests for that, the damage of Safety Relief Valves (SRVs) located at the exit of Safety Injection Pumps (SIPs) has been observed and issued recently. To resolve this issue, the opening cause of SRVs was examined from system design, piping design and operating condition. SRV performs the function of thermal relief to protect the over-pressure depending on the temperature increase in the isolated piping. We recognized that the thermal expansion did not result in the opening of SRV because there was not the cause increasing the temperature in piping at that time. In addition, it was examined that there wasn't the external cause increasing the pressure in piping to the set pressure (144.0kg/m{sup 2}) of SRV. To confirm this, mini-flow tests for SIP performance were carried out again through enough air venting in the early of 2015. As shown in table 1, the results following SIPs startup were reasonable. Otherwise, maximum pressure was greater than 142.0 kg/m{sup 2} and the fluctuation of pressure was also greater than 10.0 kg/m{sup 2} in the results of 2014 having the possibility of air present in piping and the damage of SRV. So, the objective of this paper is to evaluate pressure transients depending upon air present in SI piping as the opening cause of SKN 3 SRVs. The damage of SRVs located at the exit of SIP has been observed during pre-operation and tests of SKN 3. According to the possibility of air present in SI piping, its effect for pressure transient was evaluated at the same condition using RELAP5 code. The evaluation results for various cases demonstrate that the compression and expansion of trapped air in piping following SIP startup happen and have an effect on the opening of SRV by inducing the fluctuation of pressure and over-pressure in excess of set pressure. Also, the sensitivity results for the amount of air show that the maximum pressure in SI piping is different depending upon the amount of air and the optimal amount of

  17. Quality and Safety in Health Care, Part XXX: Transcatheter Aortic Valve Therapy.

    Science.gov (United States)

    Harolds, Jay A

    2017-12-01

    Initially, the transcatheter aortic valve replacement procedure was approved only for patients with aortic stenosis that was both severe and symptomatic who either also had too high a risk of aortic valve replacement surgery to have the surgery or who had a high risk for the surgery. Between the years 2012 and 2015, the death rate at 30 days declined from an initial rate of 7.5% to 4.6%. There has also been more use of the transfemoral approach over the years. In 2016, the transcatheter aortic valve replacement was approved for patients with aortic stenosis at intermediate risk of surgery.

  18. Safety and efficacy of using the Viabahn endoprosthesis for percutaneous treatment of vascular access complications after transfemoral aortic valve implantation

    DEFF Research Database (Denmark)

    De Backer, Ole; Arnous, Samer; Sandholt, Benjamin

    2015-01-01

    Vascular access complications (VACs) remain one of the biggest challenges when performing transcatheter aortic valve implantation (TAVI). This study aimed to investigate the short- and medium-term safety and efficacy of the Viabahn endoprosthesis (Gore, Flagstaff, AZ) when used to treat TAVI......-induced vascular injury. Over a 40-month period, 354 patients underwent true percutaneous transfemoral (TF)-TAVI using a CoreValve and Prostar-XL closure system; this was our study population. A VAC leading to acute intervention occurred in 72 patients (20.3%) - of these, 18 were managed by balloon angioplasty, 48...... stenting versus patients without vascular complications. Two patients (4.5%) presented with new-onset claudication; one of them had the stent implanted covering the deep femoral artery (DFA). At medium-term follow-up (median 372 days; range 55 to 978 days) duplex ultrasound showed 100% patency...

  19. Chemical Safety Alert: Shaft Blow-Out Hazard of Check and Butterfly Valves

    Science.gov (United States)

    Certain types of check and butterfly valves can undergo shaft-disk separation and fail catastrophically, even when operated within their design limits of pressure and temperature, causing toxic/flammable gas releases, fires, and vapor cloud explosions.

  20. Safety life cycle analysis applied to the engineering of pressure relief valves in process plants

    OpenAIRE

    Basco Montia, Josep

    2016-01-01

    Chemical plants and other industrial installations process and store hazardous materials, which represent a certain risk to people, equipment and the environment. Overpressure is one of the most common upsets in process plants and relief devices (pressure relief valves, rupture discs, overpressure-vacuum valves) are required on process equipment to prevent internal pressures from rising to levels, which could cause catastrophic equipment failure. They are the ultimate line of protection again...

  1. Application of RELAP5/MOD3.3 to Calculate Thermal Hydraulic Behavior of the Pressurizer Safety Valve Performance Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Hyun; Kim, Young Ae; Oh, Seung Jong; Park, Jong Woon [Korea Hydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of)

    2007-10-15

    The increase of the acceptance tolerance of Pressurizer Safety Valve (PSV) test is vital for the safe operation of nuclear power plants because the frequent tests may make the valves decrepit and become a cause of leak. Recently, Korea Hydro and Nuclear Power Company (KHNP) is building a PSV performance test facility to provide the technical background data for the relaxation of the acceptance tolerance of PSV including the valve pop-up characteristics and the loop seal dynamics (if the plant has the loop seal in the upstream of PSV). The discharge piping and supports must be designed to withstand severe transient hydrodynamic loads when the safety valve actuates. The evaluation of hydrodynamic loads is a two-step process: first the thermal hydraulic behavior in the piping must be defined, and then the hydrodynamic loads are calculated from the thermal hydraulic parameters such as pressure and mass flow. The hydrodynamic loads are used as input to the structural analysis.

  2. [Clinical efficacy and safety of FP-7 Ahmed glaucoma valve implantation in neurovascular glaucoma patients].

    Science.gov (United States)

    Bai, Yu-jing; Wang, Mei; Li, Yi-qing; Chai, Fang; Wei, Yan-tao; Zhang, Yi-chong; Yang, Xue-jiao; Ge, Jian; Zhuo, Ye-hong

    2011-10-01

    To evaluate the efficacy and safety of FP-7 Ahmed glaucoma valves (AGV) implantation in neurovascular glaucoma (NVG) as the first choice of surgery. This retrospective, comparative case series study collected a total of 36 eyes of 36 patients with neurovascular glaucoma who underwent AGV implantation in Zhongshan Ophthalmic Center from January 2009 to June 2010. Change of intraocular pressure (IOP), the best corrected visual acuity, numbers of anti-glaucoma medication, success rate and postoperative complications were followed up at day 1, week 1, month 1, and every 3 months after surgery. Complete success of surgery was rated as reduction of IOP ≥ 30% without medication and those who failed to meet criteria was rated as partial success. Data were analyzed by paired Student t-test for IOP, rank sum test for paired non-parametric numbers of medication, and repeated measures analysis of variance for comparison of IOP between different time points using SPSS 13.0. Compared with pre-operation, IOP was significant (F = 9.26, P AGV implantation (39.5 ± 9.7) mm Hg (1 mm Hg = 0.133 kPa) vs (9.2 ± 8.9), (11.8 ± 3.8), (13.7 ± 4.8), (16.9 ± 5.3), (16.9 ± 6.8) mm Hg at day 1, week 1, month 1, month 3 and the last following-up of post-operation, respectively. The numbers of anti-glaucoma medication were significantly (Z = 6.764, P AGV implantation was 80.6%, and qualified success rate was 91.7%. The postoperative complications including occlusion of the drainage tube, exposure of the drainage tube, shallow anterior chamber and encapsulated cystic blebs around the plate were controlled with additional treatment. The clinical outcome indicated that the implantation of FP-7 AGV has a stable IOP lowering effect and fewer complications, which can be considered as one of the first choices for management of NVG.

  3. Safety of long-term treatment with cabergoline on cardiac valve disease in patients with prolactinomas.

    Science.gov (United States)

    Auriemma, Renata S; Pivonello, Rosario; Perone, Ylenia; Grasso, Ludovica F S; Ferreri, Lucia; Simeoli, Chiara; Iacuaniello, Davide; Gasperi, Maurizio; Colao, Annamaria

    2013-09-01

    Cabergoline (CAB) has been found to be associated with increased risk of cardiac valve regurgitation in Parkinson's disease, whereas several retrospective analyses failed to detect a similar relation in hyperprolactinemic patients. The current study aimed at investigating cardiac valve disease before and after 24 and 60 months of continuous treatment with CAB only in patients with hyperprolactinemia. Forty patients (11 men and 29 women, aged 38.7 ± 12.5 years) newly diagnosed with hyperprolactinemia entered the study. Cumulative CAB dose ranged from 12 to 588 mg (median 48 mg) at 24 months and 48-1260 mg (median 149 mg) at 60 months. All patients underwent a complete trans-thoracic echocardiographic examination. Valve regurgitation was assessed according to the American Society of Echocardiography. At baseline, the prevalence of trace mitral, aortic, pulmonic, and tricuspid regurgitations was 20, 2.5, 10, and 40% respectively, with no patient showing clinically relevant valvulopathy. After 24 months, no change in the prevalence of trace mitral (P=0.78) and pulmonic (P=0.89) regurgitations and of mild aortic (P=0.89) and tricuspid (P=0.89) regurgitations was found when compared with baseline. After 60 months, the prevalence of trace tricuspid regurgitation was only slightly increased when compared with that after 24 months (37.5%; P=0.82), but none of the patients developed significant valvulopathy. No correlation was found between cumulative dose and prevalence or grade of valve regurgitation at both evaluations. Prolactin levels normalized in all patients but one. CAB does not increase the risk of significant cardiac valve regurgitation in prolactinomas after the first 5 years of treatment.

  4. A comparison of dabigatran etexilate with warfarin in patients with mechanical heart valves: THE Randomized, phase II study to evaluate the safety and pharmacokinetics of oral dabigatran etexilate in patients after heart valve replacement (RE-ALIGN).

    Science.gov (United States)

    Van de Werf, Frans; Brueckmann, Martina; Connolly, Stuart J; Friedman, Jeffrey; Granger, Christopher B; Härtter, Sebastian; Harper, Ruth; Kappetein, Arie Pieter; Lehr, Thorsten; Mack, Michael J; Noack, Herbert; Eikelboom, John W

    2012-06-01

    Vitamin K antagonists are the only oral anticoagulants approved for long-term treatment of patients with a cardiac valve replacement. This study aims to test a new dosing regimen for dabigatran etexilate in patients with a mechanical bileaflet valve. Patients aged ≥ 18 years and ≤ 75 years, either undergoing implantation of a mechanical bileaflet valve (aortic or mitral or both) during the current hospital stay or having undergone implantation a mitral bileaflet valve >3 months before randomization, will be randomized between dabigatran etexilate or warfarin (in a ratio of 2:1) in an open-label design. Initial doses of dabigatran will be based on the estimated creatinine clearance, and the doses will be adjusted based on measuring trough dabigatran plasma levels to achieve levels ≥ 50 ng/mL at steady state. Doses will range between 150 mg twice a day and 300 mg twice a day. Warfarin management and target international normalized ratio will be according to current practice guidelines at the discretion of the treating physicians. The plan is to treat 270 patients with dabigatran etexilate for a total study population of approximately 405 patients. Clinical efficacy and safety outcomes will be analyzed in an exploratory manner. RE-ALIGN is the first study to test an alternative to warfarin in patients with mechanical heart valves. A definitive phase III study will be planned based on the results of this study. Copyright © 2012 Mosby, Inc. All rights reserved.

  5. Safety and predictors of next-day discharge after elective transfemoral transcatheter aortic valve replacement.

    Science.gov (United States)

    Rathore, Sulaiman; Latyshev, Yevgeniy; Emore, Sheree; Rowe, Joseph; Foerst, Jason

    2017-12-01

    We sought to determine the predictors of next-day discharge (NDD) for selected patients undergoing elective transfemoral transcatheter aortic valve replacement (TF-TAVR). Techniques have rapidly evolved over the last several years to simplify TF-TAVR allowing for a subset of patients to be discharged the next day. Baseline and procedural characteristics, in-hospital and 30-day follow-up outcomes, complications and readmission rates of 100 TF-TAVR cases were assessed. Patients selected for NDD all met the following criteria: no procedural complications, same day ambulation, strong family support with home supervision, and access to our valve coordinator post discharge. There were 22 patients in NDD and 78 in later-day discharge (LDD) groups respectively. The mean length of stay was 3.4days for LDD. There were no significant differences in baseline, pre-procedural characteristics, or frailty indices of the two groups. However, there were more baseline oxygen dependent patients in LDD (p=0.004). Procedural characteristics included more balloon expandable valves (p=0.005), less fluoroscopy time (p=0.008), and higher use of moderate sedation (p=0.0001) in NDD group. There were more minor vascular complications (p=0.04) and new permanent pacemaker implantations (p=0.016) in the LDD group. There were no vascular complications, stroke or blood transfusions in the NDD group. The 30-day re-admission and mortality rates were similar in both groups. In logistic analyses only moderate sedation was a strong predictor of next day discharge after TF-TAVR (p=0.003). Carefully selected patients without complications following TF-TAVR can be discharged safely the next day. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Early safety outcome following transcatheter aortic valve implantation: is the amount of contrast media used a matter of concern?

    Science.gov (United States)

    Vontobel, Jan; Possner, Mathias; Schütz, Philipp; Müller, Beat; Taramasso, Maurizio; Binder, Roland K; Haueis, Sabine; Attinger-Toller, Adrian; Maisano, Francesco; Nietlispach, Fabian

    2015-01-01

    The study objective was to evaluate the impact of the amount of contrast medium used for transcatheter aortic valve implantation (TAVI) on short-term outcome. Patients undergoing TAVI are exposed to repeat contrast medium application both for preprocedural screening and during the TAVI procedure itself. Whether the amount of contrast media is associated with worse outcome is unclear. A total of 257 patients were included (median age 82.7 years) and divided into two groups with preserved and reduced kidney function (glomerular filtration rate contrast media administered during and within 5 days prior to TAVI was analysed. A combined early safety endpoint at 30 days was evaluated. The early safety endpoint was reached by 31 patients and acute kidney injury occurred in 22 patients. The median total volume of contrast media administered was 144 ml (interquartile range 81-225 ml). The amount of contrast did not independently predict the early safety endpoint in the overall population (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.56 to 1.53, p = 0.774) and in subgroups with preserved and reduced kidney function. Change in creatinine was an independent strong predictor of the early safety endpoint in the overall population (OR 18.13, 95% CI 4.70 to 69.99, p contrast did not predict a change in creatinine within 72 hours following TAVI (r = 0.02, 95% CI -0.02 to 0.07, p = 0.368). Decreased kidney function after TAVI influences outcome. When rather small amounts of contrast media are used for screening and the TAVI procedure itself, the amount of contrast media seems not to be an independent predictor of outcome, further suggesting that decreased kidney function after TAVI is multifactorial.

  7. Efficacy and Safety of Transcatheter Aortic Valve Implantation in Aortic Stenosis Patients With Extreme Age.

    Science.gov (United States)

    Orvin, Katia; Assali, Abid; Vaknin-Assa, Hana; Levi, Amos; Greenberg, Gabi; Codner, Pablo; Shapira, Yaron; Sagie, Alex; Kornowski, Ran

    2015-10-01

    To investigate the in-hospital and long-term outcomes of patients at extreme age with severe symptomatic aortic stenosis (AS) who underwent transcatheter aortic valve implantation (TAVI). A total of 276 consecutive patients with a mean age of 82.2 ± 5.0 years with severe symptomatic AS underwent TAVI at our institute. We evaluated periprocedural, in-hospital, and long-term outcomes in all patients aged ≥87 years (the highest 20th percentile of age distribution) and compared them with the less elderly patients. The extremely aged group included 58 patients (21%) ≥87 years (mean age, 89.0 ± 1.9 years; 67.2% women). Baseline EuroSCOREs and STS scores were 19.6 ± 11.2% and 9.4 ± 5.0%, respectively. Nineteen patients (34.5%) were considered frail. Following TAVI, all patients regained New York Heart Association class 1-2 functional capacity. The main periprocedural and in-hospital complications were minor vascular complications, bleeding requiring blood transfusions, and the need for permanent pacemaker. None of the patients suffered from clinical stroke. In comparison to the less elderly patients, there were no significant differences in the rates of periprocedural, in-hospital complications or long-term survival (log rank, 0.87). Meticulously selected patients at extreme age benefit from TAVI with a reasonable overall risk, which does not impact the overall survival or functional status.

  8. Efficacy and safety of low molecular weight heparin in patients with mechanical heart valves: systematic review and meta-analysis.

    Science.gov (United States)

    Caldeira, D; David, C; Santos, A T; Costa, J; Pinto, F J; Ferreira, J J

    2014-05-01

    Low molecular weight heparins (LMWHs) are not approved for patients with mechanical heart valves (MHVs). However, in several guidelines, temporary LMWH off-label use in this clinical setting is considered to be a valid treatment option. Therefore, we reviewed the efficacy and safety of LMWHs in patients with MHVs. MEDLINE and CENTRAL databases were searched from inception to June 2013. Review articles and references were also searched. We included experimental and observational studies that compared LMWHs with unfractionated heparin (UFH) or vitamin K antagonists (VKAs). Data were analyzed and pooled to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for thromboembolic and major bleeding events. Statistical heterogeneity was evaluated with the I(2) -test. Nine studies were included: one randomized controlled trial (RCT) and eight observational studies, with a total of 1042 patients. No differences were found between LMWHs and UFH/VKAs in the risk of thromboembolic events (OR 0.67; 95% CI 0.27-1.68; I(2) = 9%) or major bleeding events (OR 0.66; 95% CI 0.36-1.19; I(2) = 0%). The best evidence available might support the temporary use of LMWHs as a prophylactic treatment option in patients with MHVs. However, conclusions are mostly based on observational data (with large CIs), and an adequately powered RCT is urgently needed in this clinical setting. © 2014 International Society on Thrombosis and Haemostasis.

  9. Feasibility, safety, and efficacy of transcatheter aortic valve replacement without balloon predilation: A systematic review and meta-analysis.

    Science.gov (United States)

    Auffret, Vincent; Regueiro, Ander; Campelo-Parada, Francisco; Del Trigo, María; Chiche, Olivier; Chamandi, Chekrallah; Puri, Rishi; Rodés-Cabau, Josep

    2017-11-01

    To evaluate the feasibility, safety, and efficacy of direct transcatheter aortic valve replacement (TAVR), that is, TAVR without balloon predilation (BPD), by performing a systematic review and meta-analysis of available evidence. Avoiding BPD during TAVR was shown to be feasible in previous studies but the risks and benefits of this technique are unknown owing to the limited number of patients included in these studies. We performed a systematic search for studies comparing direct TAVR vs TAVR performed with BPD. Crude risk ratios (RRs) or mean differences and 95% confidence intervals (CI) for each endpoint were calculated using random effects models. Twenty studies including 3586 patients (1606 undergoing direct TAVR) were selected for the analysis. Mean device success with direct TAVR was 88% with <5% of bail-out techniques. There were no differences between direct and BPD-TAVR in short-term (in-hospital or 30-day) mortality (RR: 1.06; 95% CI: 0.78-1.43) or cerebrovascular events (RR: 0.92; 95% CI: 0.58-1.46). Direct TAVR associated with reduced moderate or severe paravalvular leak post-TAVR (RR: 0.59; 95% CI: 0.36-0.98) but not with a reduced risk of permanent pacemaker implantation (RR: 0.85, 95% CI: 0.71-1.02). A slight increase in postdilation was observed in direct transfemoral-TAVR recipients (RR: 1.2; 95% CI: 1.00-1.44). Direct TAVR is feasible and safe. However, given the unadjusted nature of our results, uncertainties remain regarding the independent effect of direct TAVR on outcomes post-TAVR. Randomized studies are warranted to determine the potential benefits of direct TAVR. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  10. Valve Disease

    Science.gov (United States)

    ... See also on this site: Diseases of the Mitral Valve Diseases of the Aortic Valve Diseases of the Tricuspid ... most invasive option for the treatment of valve disease. During surgery, ... defects of the mitral valve. Replacement is used to treat any diseased ...

  11. Safety and Efficacy of Transcatheter Aortic Valve Replacement in the Treatment of Pure Aortic Regurgitation in Native Valves and Failing Surgical Bioprostheses

    DEFF Research Database (Denmark)

    Sawaya, Fadi J; Deutsch, Marcus-André; Seiffert, Moritz

    2017-01-01

    %, respectively). Independent predictors of 30-day mortality were body mass index 8%, major vascular or access complication, and moderate to severe AR. In the failing SHV group, device success, early safety, and clinical efficacy were 71%, 90%, and 77%, respectively...

  12. First Reported Successful Femoral Valve-in-Valve Transcatheter Aortic Valve Replacement Using the Edwards Sapien 3 Valve.

    Science.gov (United States)

    Fournier, Stephane; Monney, Pierre; Roguelov, Christan; Zuffi, Andrea; Iglesias, Juan F; Qanadli, Salah D; Courbon, Cecile; Eeckhout, Eric; Muller, Olivier

    2015-10-01

    Management of degenerated aortic valve bioprosthesis classically requires redo surgery, but transcatheter aortic valve-in-valve implantation is becoming a valid alternative in selected cases. In the case of a degenerated Mitroflow bioprosthesis, TAVR is associated with an additional challenge due to a specific risk of coronary occlusion. We aimed to assess the safety and feasibility of transfemoral valve-in-valve implantation of the new Edwards Sapien 3 (Edwards Lifesciences) in a degenerated Mitroflow bioprosthesis (Sorin Group, Inc). We report here the safety and feasibility of transfemoral valve-in-valve implantation of a 23 mm Edwards Sapien 3 in a degenerated 25 mm Mitroflow valve and describe the specific assessment of the risk of coronary obstruction using a multi-imaging modality. The final result showed an absence of aortic regurgitation and a mean transvalvular gradient of 14 mm Hg. The patient had no major adverse cardiovascular events at 30-day follow-up. Transcatheter valve-in-valve implantation of an Edwards Sapien 3 in a degenerated Mitroflow is feasible and safe, considering a careful assessment of the risk of coronary obstruction with Mitroflow bioprosthesis due to leaflets mounted externally to the stent.

  13. Heart valve surgery

    Science.gov (United States)

    Valve replacement; Valve repair; Heart valve prosthesis; Mechanical valves; Prosthetic valves ... can relieve your symptoms and prolong your life. Mechanical heart valves do not often fail. However, blood clots can ...

  14. 49 CFR 195.420 - Valve maintenance.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valve maintenance. 195.420 Section 195.420 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Operation and Maintenance § 195.420 Valve maintenance. (a) Each operator shall maintain each valve...

  15. Studies for the requirements of automatic and remotely controlled shutoff valves on hazardous liquids and natural gas pipelines with respect to public and environmental safety

    Energy Technology Data Exchange (ETDEWEB)

    Oland, C. Barry [XCEL Engineering, Inc. (United States); Rose, Simon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Engineering Science and Technology Div.; Grant, Herb L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fabrication, Hoisting and Rigging Div.; Lower, Mark D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fabrication, Hoisting and Rigging Div.; Spann, Mark A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Facility Management Div.; Kirkpatrick, John R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computational Sciences and Engineering Div.; Sulfredge, C. David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computational Sciences and Engineering Div.

    2012-12-01

    This study assesses the effectiveness of block valve closure swiftness in mitigating the consequences of natural gas and hazardous liquid pipeline releases on public and environmental safety. It also evaluates the technical, operational, and economic feasibility and potential cost benefits of installing automatic shutoff valves (ASVs) and remote control valves (RCVs) in newly constructed and fully replaced transmission lines. Risk analyses of hypothetical pipeline release scenarios are used as the basis for assessing: (1) fire damage to buildings and property in Class 1, Class 2, Class 3, and Class 4 high consequence areas (HCAs) caused by natural gas pipeline releases and subsequent ignition of the released natural gas; (2) fire damage to buildings and property in HCAs designated as high population areas and other populated areas caused by hazardous liquid pipeline releases and subsequent ignition of the released propane; and (3) socioeconomic and environmental damage in HCAs caused by hazardous liquid pipeline releases of crude oil. These risk analyses use engineering principles and fire science practices to characterize thermal radiation effects on buildings and humans and to quantify the total damage cost of socioeconomic and environmental impacts. The risk analysis approach used for natural gas pipelines is consistent with risk assessment standards developed by industry and incorporated into Federal pipeline safety regulations. Feasibility evaluations for the hypothetical pipeline release scenarios considered in this study show that installation of ASVs and RCVs in newly constructed and fully replaced natural gas and hazardous liquid pipelines is technically, operationally, and economically feasible with a positive cost benefit. However, these results may not apply to all newly constructed and fully replaced pipelines because site-specific parameters that influence risk analyses and feasibility evaluations often vary significantly from one pipeline segment to

  16. Impact of Mean Platelet Volume on Combined Safety Endpoint and Vascular and Bleeding Complications following Percutaneous Transfemoral Transcatheter Aortic Valve Implantation

    Directory of Open Access Journals (Sweden)

    Caroline J. Magri

    2013-01-01

    Full Text Available Background. Vascular and bleeding complications remain important complications in patients undergoing percutaneous transfemoral transcatheter aortic valve implantation (TF-TAVI. Platelets play an important role in bleeding events. Mean platelet volume (MPV is an indicator of platelet activation. The objective of this study was to assess whether low MPV is an indicator of major vascular and bleeding complications following TF-TAVI. Methods. A retrospective cohort study of 330 subjects undergoing TF-TAVI implantation was performed. The primary study endpoint was the occurrence of combined safety endpoint (CSEP; secondary endpoints included major vascular complications and life-threatening bleeding. Endpoints were defined according to Valve Academic Research Consortium 2. Results. The CSEP at 30 days was reached in 30.9%; major vascular complications were observed in 14.9% while life-threatening bleeding occurred in 20.6%. Logistic Euroscore and MPV were independent predictors of CSEP. Predictors of vascular complications were female sex, previous myocardial infarction, red blood cell distribution width (RDW, and MPV while predictors of life-threatening bleeding were peripheral arterial disease, RDW, and MPV. Conclusion. A low baseline MPV was shown for the first time to be a significant predictor of CSEP, major vascular complications, and life-threatening bleeding following TF-TAVI.

  17. Testing of calibration and reconditioning of the pressurizer safety valves; Pruebas de tarado y reacondicionamiento de las valvulas de seguridad del presionador

    Energy Technology Data Exchange (ETDEWEB)

    Mediavilla, F.; Jardi, X.

    2014-07-01

    This paper presents All activities that are required in the proposal of Tecnatom as: transport of valves to the laboratory in special containers and preparation of the expedition of the radioactive packages testing of leakage of valves with nitrogen, leak and calibration with initial steam and final tests, overhaul of the valve including the process Jack and Lap and mounting and dismounting of valves in the plant. (Author)

  18. A New Method Solving Contact/Detach Problem in Fluid and Structure Interaction Simulation with Application in Modeling of a Safety Valve

    Directory of Open Access Journals (Sweden)

    Zheng Guo

    2010-01-01

    Full Text Available A new virtual baffle methodology is implemented to solve contact/detach problem which is often encountered in fluid and structure interaction simulations while using dynamic grids technique. The algorithm is based on tetrahedral unstructured grid, and a zero thickness baffle face is generated between actually contacted two objects. In computation process, this baffle face is divided into two parts representing convective and blocked area, respectively; the area of each part is calculated according to the actual displacement between the two objects. Convective part in a baffle face is treated as inner interface between cells, and on blocked part wall boundary condition is applied; so convective and blocking effect can be achieved on a single baffle face. This methodology can simulate real detaching process starting from contact, that is, zero displacement, while it has no restriction to minimum grid cell size. The methodology is then applied in modeling of a complicated safety valve opening process, involving multidisciplinary fluid and structure interaction and dynamic grids. The results agree well with experimental data, which proves that the virtual baffle method is successful.

  19. Propellant actuated nuclear reactor steam depressurization valve

    Science.gov (United States)

    Ehrke, Alan C.; Knepp, John B.; Skoda, George I.

    1992-01-01

    A nuclear fission reactor combined with a propellant actuated depressurization and/or water injection valve is disclosed. The depressurization valve releases pressure from a water cooled, steam producing nuclear reactor when required to insure the safety of the reactor. Depressurization of the reactor pressure vessel enables gravity feeding of supplementary coolant water through the water injection valve to the reactor pressure vessel to prevent damage to the fuel core.

  20. Predictive modelization of actuators tires in related valves with safety Cofrentes NPP; Modelizacion predictiva de actuadores neumaticos en valvulas relacionadas con la seguridad de C.N.Cofrentes

    Energy Technology Data Exchange (ETDEWEB)

    Calduch Cervera, F.; Verdu Rios, M. F.; Villena Rivera, M.; Munoz Guijosa, J. M.

    2011-07-01

    The main function of these valves is isolation, and in some cases this function is especially critical because they must isolate Elementary and Secondary Containment. Particularly valves must be able to ensure a perfect sealing of the lines which are installed under any conditions, whether in normal operation or in a design basis accident scenario.

  1. Piezoelectric valve

    Science.gov (United States)

    Petrenko, Serhiy Fedorovich

    2013-01-15

    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  2. 49 CFR 192.181 - Distribution line valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Distribution line valves. 192.181 Section 192.181 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... line valves. (a) Each high-pressure distribution system must have valves spaced so as to reduce the...

  3. 49 CFR 192.745 - Valve maintenance: Transmission lines.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valve maintenance: Transmission lines. 192.745... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.745 Valve maintenance: Transmission lines. (a) Each transmission line valve that might be required during any emergency...

  4. Efficacy and safety of intravitreal ranibizumab with panretinal photocoagulation followed by trabeculectomy compared with Ahmed glaucoma valve implantation in neovascular glaucoma.

    Science.gov (United States)

    Sun, Jin-Tao; Liang, Hai-Jing; An, Meng; Wang, Da-Bo

    2017-01-01

    To evaluate the efficacy and safety of intravitreal ranibizumab (IVR) with panretinal photocoagulation (PRP) followed by trabeculectomy compared with Ahmed glaucoma valve (AGV) implantation in neovascular glaucoma (NVG). This was a retrospective comparative study. We reviewed the cases of a total of 45 eyes from 45 NVG patients among which 23 eyes underwent AGV implantation and the other 22 underwent trabeculectomy. The causes of neovascular glaucoma included: diabetic retinopathy (25 eyes), and retinal vein occlusion (20 eyes). All patients received preoperative IVR combined with postoperative PRP. The mean best-corrected visual acuities (BCVA) were converted to the logarithms of the minimum angle of resolution (logMAR) for the statisitical analyses. Intraocular pressure (IOP), the logMAR BCVA and surgical complications were evaluated before and after surgery. The follow-up period was 12mo. A total of 39 cases showed complete regression of iris neovascularization at 7d after injection, and 6 cases showed a small amount of residual iris neovascularization. The success rates were 81.8% and 82.6% at 12mo after trabeculectomy and AGV implantation, respectively. In the trabeculectomy group, the logMAR BCVA improved at the last follow-up in 14 eyes, remained stable in 6 eyes and decreased in 2 eyes. In 4 cases, slight hyphemas developed after trabeculectomy. A shallow anterior chamber developed in 2 cases and 2 vitreous hemorrhages. In the AGV group, the logMAR BCVA improved in 14 eyes, remained stable in 5 eyes and decreased in 4 eyes. Slight hyphemas developed in 3 cases, and a shallow anterior chamber in 3 cases. The mean postoperative IOP was significantly lower in both groups after surgery (F=545.468, PAGV implantation+PRP and IVR+trabeculectomy+PRP in eyes with NVG.

  5. Thrombolytic therapy in prosthetic valve thrombosis during early pregnancy

    Directory of Open Access Journals (Sweden)

    B.C. Srinivas

    2012-01-01

    Full Text Available Regardless of the improvements in the design of prosthetic heart valves and the use of anticoagulation, systemic embolism and valve thrombosis remains the most dreaded complications of mechanical heart valve replacement. A course of thrombolytic therapy may be considered as a first-line therapy for prosthetic heart valve thrombosis. The safety of thrombolysis in early pregnancy is not known. We describe a primigravida with mitral valve replacement status presenting with acute prosthetic valve thrombosis and treated successfully with intravenous streptokinase.

  6. Pump arrangement Comprising a Savety Valve

    OpenAIRE

    Richter, M.; Kruckow, J.

    2009-01-01

    A pump arrangement comprises a pump (20) having a pump inlet (22) and a pump outlet (24), which are designed to pump a fluid from the pump inlet to the pump outlet, and it further comprises a safety valve (40), which is disposed between the pump outlet (24) and an outlet (48) of the pump arrangement and comprises a valve set (42) and a valve cover (44). The valve seat, the pump outlet, and the pump inlet are structured in a first surface of a first single-piece part (14) of the pump arrangeme...

  7. Valve's Way

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Dobrajska, Magdalena

    2015-01-01

    to what extent it represents a new blueprint for organization design, despite it being consistent with an “egalitarian Zeitgeist” (Puranam, 2014). In fact, managerial authority may be of increasing importance rather than the opposite (Guadalupe, Li, & Wulf, 2015). Thus, Valve is, and will remain...

  8. Vacuum Valve

    CERN Multimedia

    1974-01-01

    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  9. Engineering and maintenance applied to safety-related valves in nuclear power plants; Ingenieria y mantenimiento aplicado a valvulas relacionadas con la seguridad en centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Verdu, M. F.; Perez-Aranda, J.

    2014-04-01

    Nuclear Division in Iberdrola engineering and Construction has a team with extensive experience on engineering and services works related to valves. Also, this team is linked to UNESA as Technical support and Reference Center. Iberdrola engineering and construction experience in nuclear power plants valves, gives effective response to engineering and maintenance works that can be demanded in a nuclear power plant and it requires a high degree of qualification and knowledge both in Operation and Outages. (Author)

  10. Transcatheter Pulmonary Valve Replacement by Hybrid Approach Using a Novel Polymeric Prosthetic Heart Valve: Proof of Concept in Sheep

    OpenAIRE

    Ben Zhang; Xiang Chen; Tong-yi Xu; Zhi-gang Zhang; Xin Li; Lin Han; Zhi-yun Xu

    2014-01-01

    Background Since 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach. Methods We designed a novel polymeric trileaflet transcatheter pulmo...

  11. Butterfly valve. Spjeldventil

    Energy Technology Data Exchange (ETDEWEB)

    Cupedo, D.J.

    1984-02-06

    Butterfly valve comprising a body and a valve seat arranged therein, on which a valve member is supported. The valve member comprises an operating rod and the assembly of valve member and operating rod has a fixed pivot point at the bottom of the body. The operating rod can be moved by means of pins movable in grooves and slots in such a manner that when the valve is opened the valve member first pivots about the pivot point to lift the valve member from the seat and subsequently rotates about the pivot point to fully open the valve. 12 drawings.

  12. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik

    2013-01-01

    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  13. Efficacy and safety of intravitreal ranibizumab with panretinal photocoagulation followed by trabeculectomy compared with Ahmed glaucoma valve implantation in neovascular glaucoma

    Directory of Open Access Journals (Sweden)

    Jin-Tao Sun

    2017-03-01

    Full Text Available AIM: To evaluate the efficacy and safety of intravitreal ranibizumab (IVR with panretinal photocoagulation (PRP followed by trabeculectomy compared with Ahmed glaucoma valve (AGV implantation in neovascular glaucoma (NVG. METHODS: This was a retrospective comparative study. We reviewed the cases of a total of 45 eyes from 45 NVG patients among which 23 eyes underwent AGV implantation and the other 22 underwent trabeculectomy. The causes of neovascular glaucoma included: diabetic retinopathy (25 eyes, and retinal vein occlusion (20 eyes. All patients received preoperative IVR combined with postoperative PRP. The mean best-corrected visual acuities (BCVA were converted to the logarithms of the minimum angle of resolution (logMAR for the statisitical analyses. Intraocular pressure (IOP, the logMAR BCVA and surgical complications were evaluated before and after surgery. The follow-up period was 12mo. RESULTS: A total of 39 cases showed complete regression of iris neovascularization at 7d after injection, and 6 cases showed a small amount of residual iris neovascularization. The success rates were 81.8% and 82.6% at 12mo after trabeculectomy and AGV implantation, respectively. In the trabeculectomy group, the logMAR BCVA improved at the last follow-up in 14 eyes, remained stable in 6 eyes and decreased in 2 eyes. In 4 cases, slight hyphemas developed after trabeculectomy. A shallow anterior chamber developed in 2 cases and 2 vitreous hemorrhages. In the AGV group, the logMAR BCVA improved in 14 eyes, remained stable in 5 eyes and decreased in 4 eyes. Slight hyphemas developed in 3 cases, and a shallow anterior chamber in 3 cases. The mean postoperative IOP was significantly lower in both groups after surgery (F=545.468, P<0.05, and the mean postoperative logMAR BCVA was also significantly improved (F=10.964, P<0.05 with no significant difference between two groups. CONCLUSION: It is safe and effective to treat NVG with this combined procedure, and we

  14. Aortic Valve Stenosis

    Science.gov (United States)

    ... rapid, fluttering heartbeat Not eating enough (mainly in children with aortic valve stenosis) Not gaining enough weight (mainly in children with aortic valve stenosis) The heart-weakening effects of aortic valve stenosis ...

  15. What Is Heart Valve Disease?

    Science.gov (United States)

    ... Heart Valves Sometimes heart valves can’t be repaired and must be replaced. This surgery involves removing the faulty valve and replacing it with a man-made or biological valve. Biological valves are made ...

  16. Sutureless Valves Reduce Hospital Costs Compared to Traditional Valves.

    Science.gov (United States)

    Laborde, François; Folliguet, Thierry; Ghorayeb, Gabriel; Zannis, Konstantinos

    2017-01-01

    The study aim was to assess differences in clinical outcome, safety, and associated costs between sutureless and aortic isolated aortic valve replacement (AVR) with a standard bioprosthesis. A retrospective comparative study was conducted to investigate 65 patients, each of whom had undergone isolated AVR with a traditional aortic valve (T) or a Perceval S sutureless aortic prosthesis (P) between January 2010 and December 2012. Cost data were drawn from the proprietary cost accounting system of the hospital, excluding acquisition costs of the devices. A linear regression model was used to estimate the mean total costs difference between groups. The mean cardiopulmonary bypass time and aortic cross-clamp times in the T and P groups were 80 ± 41 min and 58 ± 26 min versus 38 ± 16 min and 26 ± 10 min, respectively (p costs savings for group P compared to group T were €3,801 (p = 0.13), mainly driven by hospital stay costs. Savings between the P and T groups increased with age: €4,992 in patients aged 70-79 years and €9,326 in those aged 80+ years, and with risk (€4,296 for high-risk patients). Sutureless aortic valves present shorter procedural times and lower hospital costs compared to traditional valves, with higher cost savings at increased patient age and risk. Sutureless aortic valves seem to be cost-effective in patients undergoing AVR.

  17. Robotically assisted mitral valve replacement.

    Science.gov (United States)

    Gao, Changqing; Yang, Ming; Xiao, Cangsong; Wang, Gang; Wu, Yang; Wang, Jiali; Li, Jiachun

    2012-04-01

    In the present study, we determined the safety and efficacy of robotic mitral valve replacement using robotic technology. From January 2007 through March 2011, more than 400 patients underwent various types of robotic cardiac surgery in our department. Of these, 22 consecutive patients underwent robotically assisted mitral valve replacement. Of the 22 patients with isolated rheumatic mitral valve stenosis (9 men and 13 women), the mean age was 44.7 ± 19.8 years (range, 32-65). Preoperatively, all patients underwent a complete workup, including coronary angiography and transthoracic echocardiography. Of the 22 patients, 15 had concomitant atrial fibrillation. The surgical approach was through 4 right-side chest ports with femoral perfusion. Aortic occlusion was performed with a Chitwood crossclamp, and antegrade cardioplegia was administered directly by way of the anterior chest. Using 3 port incisions in the right side of the chest and a 2.5- to 3.0-cm working port, all the procedures were completed with the da Vinci S robot. All patients underwent successful robotic surgery. Of the 22 patients, 16 received a mechanical valve and 6 a tissue valve. The mean cardiopulmonary bypass time and aortic crossclamp time was 137.1 ± 21.9 minutes (range, 105-168) and 99.3 ± 17.9 minutes (range, 80-133), respectively. No operative deaths, stroke, or other complications occurred, and no incisional conversions were required. After surgery, all the patients were followed up echocardiographically. Robotically assisted mitral valve replacement can be performed safely in patients with isolated mitral valve stenosis, and surgical results are excellent. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  18. Simulant Development for Hanford Tank Farms Double Valve Isolation (DVI) Valves Testing

    Energy Technology Data Exchange (ETDEWEB)

    Wells, Beric E.

    2012-12-21

    Leakage testing of a representative sample of the safety-significant isolation valves for Double Valve Isolation (DVI) in an environment that simulates the abrasive characteristics of the Hanford Tank Farms Waste Transfer System during waste feed delivery to the Waste Treatment and Immobilization Plant (WTP) is to be conducted. The testing will consist of periodic leak performed on the DVI valves after prescribed numbers of valve cycles (open and close) in a simulated environment representative of the abrasive properties of the waste and the Waste Transfer System. The valve operations include exposure to cycling conditions that include gravity drain and flush operation following slurry transfer. The simulant test will establish the performance characteristics and verify compliance with the Documented Safety Analysis. Proper simulant development is essential to ensure that the critical process streams characteristics are represented, National Research Council report “Advice on the Department of Energy's Cleanup Technology Roadmap: Gaps and Bridges”

  19. Transseptal transcatheter mitral valve-in-valve: A step by step guide from preprocedural planning to postprocedural care.

    Science.gov (United States)

    Guerrero, Mayra; Salinger, Michael; Pursnani, Amit; Pearson, Paul; Lampert, Mark; Levisay, Justin; Russell, Hyde; Feldman, Ted

    2017-05-30

    Transcatheter mitral valve replacement has been successfully performed with the use of aortic transcatheter heart valves in hundreds of patients worldwide with severe dysfunction of a degenerated mitral bioprosthesis and high surgical risk for repeat operation. The delivery approach in the vast majority of the mitral valve-in-valve procedures has been transapical. Although the transseptal approach may be more technically challenging, it is less invasive and may be preferred by patients. Data from case series and a large international registry suggest that patients treated with transseptal mitral valve-in-valve have faster recovery, more improvement in left ventricular ejection fraction and possibly lower mortality compared with patients treated with transapical approach. A prospective clinical trial, the MITRAL trial (Mitral Implantation of TRAnscatheter vaLves) is evaluating the safety and feasibility of transvenous transseptal mitral valve-in-valve. The experience from this trial has allowed us to improve our procedural approach. In anticipation of a wider adoption of the transseptal approach for mitral valve-in-valve, we describe our current method step-by-step from planning the procedure through postprocedural management. This is an evolving technique that has changed with experience and the transition to newer generation transcatheter heart valve devices. We discuss the use of cardiac computed tomography for planning the procedure including transseptal puncture and valve size selection, provide procedural and technical tips, and discuss postprocedural care. © 2017 Wiley Periodicals, Inc.

  20. Fire Safety (For Parents)

    Science.gov (United States)

    ... of Braces Eating Disorders Mitral Valve Prolapse Arrhythmias Fire Safety KidsHealth > For Parents > Fire Safety Print A ... event of a fire emergency in your home. Fire Prevention Of course, the best way to practice ...

  1. Remote actuated valve implant

    Science.gov (United States)

    McKnight, Timothy E; Johnson, Anthony; Moise, Jr., Kenneth J; Ericson, Milton Nance; Baba, Justin S; Wilgen, John B; Evans, III, Boyd McCutchen

    2014-02-25

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  2. Remote actuated valve implant

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.; Ericson, Milton Nance; Baba, Justin S.; Wilgen, John B.; Evans, Boyd Mccutchen

    2016-05-10

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  3. Mitral valve regurgitation

    Science.gov (United States)

    ... around the valve. You are at risk for mitral valve regurgitation if you have: Coronary heart disease and high blood pressure Infection of the heart valves Mitral valve prolapse (MVP) Rare conditions, such as untreated syphilis or Marfan ... heart disease. This is a complication of untreated strep throat ...

  4. Tissue engineered aortic valve

    OpenAIRE

    Dohmen, P M

    2012-01-01

    Several prostheses are available to replace degenerative diseased aortic valves with unique advantages and disadvantages. Bioprotheses show excellent hemodynamic behavior and low risk of thromboembolic complications, but are limited by tissue deterioration. Mechanical heart valves have extended durability, but permanent anticoagulation is mandatory. Tissue engineering created a new generation heart valve, which overcome limitations of biological and mechanical heart valves due to remodelling,...

  5. Transcatheter pulmonary valve replacement by hybrid approach using a novel polymeric prosthetic heart valve: proof of concept in sheep.

    Science.gov (United States)

    Zhang, Ben; Chen, Xiang; Xu, Tong-yi; Zhang, Zhi-gang; Li, Xin; Han, Lin; Xu, Zhi-yun

    2014-01-01

    Since 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach. We designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflets were made of 0.1-mm expanded polytetrafluoroethylene (ePTFE) coated with phosphorylcholine. We chose glutaraldehyde-treated bovine pericardium valves as control. Pulmonary valve stents were implanted in situ by a hybrid transapical approach in 10 healthy sheep (8 for polymeric valve and 2 for bovine pericardium valve), weighing an average of 22.5±2.0 kg. Angiography and cardiac catheter examination were performed after implantation to assess immediate valvular functionality. After 4-week follow-up, angiography, echocardiography, computed tomography, and cardiac catheter examination were used to assess early valvular function. One randomly selected sheep with polymeric valve was euthanized and the explanted valved stent was analyzed macroscopically and microscopically. Implantation was successful in 9 sheep. Angiography at implantation showed all 9 prosthetic valves demonstrated orthotopic position and normal functionality. All 9 sheep survived at 4-week follow-up. Four-week follow-up revealed no evidence of valve stent dislocation or deformation and normal valvular and cardiac functionality. The cardiac catheter examination showed the peak-peak transvalvular pressure gradient of the polymeric valves was 11.9±5.0 mmHg, while that of two bovine pericardium valves were 11 and 17 mmHg. Gross morphology demonstrated good opening and closure characteristics. No thrombus or calcification was seen macroscopically. This design of the

  6. SAFETY

    CERN Multimedia

    Niels Dupont

    2013-01-01

    CERN Safety rules and Radiation Protection at CMS The CERN Safety rules are defined by the Occupational Health & Safety and Environmental Protection Unit (HSE Unit), CERN’s institutional authority and central Safety organ attached to the Director General. In particular the Radiation Protection group (DGS-RP1) ensures that personnel on the CERN sites and the public are protected from potentially harmful effects of ionising radiation linked to CERN activities. The RP Group fulfils its mandate in collaboration with the CERN departments owning or operating sources of ionising radiation and having the responsibility for Radiation Safety of these sources. The specific responsibilities concerning "Radiation Safety" and "Radiation Protection" are delegated as follows: Radiation Safety is the responsibility of every CERN Department owning radiation sources or using radiation sources put at its disposition. These Departments are in charge of implementing the requi...

  7. Transcatheter aortic valve implantation with balloonexpandable valve: early experience from China

    Directory of Open Access Journals (Sweden)

    Qingsheng Lu

    2015-08-01

    Full Text Available Abstract Objective: The aim of the current study was to evaluate the early experience of the application of transcatheter aortic valve implantation with the balloon-expandable system in China. The transcatheter aortic valve implantation technology has been widely used for patients with inoperable severe aortic stenosis in the developed world. The application of transcatheter aortic valve implantation is still in the early stages of testing in China, particularly for the balloon-expandable valve procedure. Methods: This was a retrospective study. All patients undergoing transcatheter aortic valve implantation with balloon-expandable system in our hospital between 2011 and 2014 were included. Edwards SAPIEN XT Transcatheter Heart Valve was used. The improvement of valve and heart function was evaluated as well as 30-day mortality and major complications according to the VARC-2 definition. Results: A total of 10 transcatheter aortic valve implantation procedures with the balloon-expandable system were performed in our hospital, of which 9 were transfemoral and 1 was transapical. The median age was 76 years, and the median STS score and Logistic EuroSCORE (% were 8.9 and 16.2. The implantation was successfully conducted in all patients, only 2 patients had mild paravalvular leak. There was no second valve implantation. Moreover, no 30-day mortality or complications was reported. Following the transcatheter aortic valve implantation procedure, the heart and valve functions had improved significantly. During the follow-up period of 3-34 months, one patient died of lung cancer 13 months after the operation. Conclusion: This early experience has provided preliminary evidence for the safety and efficacy of transcatheter aortic valve implantation procedure with the balloon-expandable system in the developing world with an increasing aging population.

  8. Risks for Heart Valve Problems

    Science.gov (United States)

    ... Thromboembolism Aortic Aneurysm More Risks for Heart Valve Problems Updated:Jan 18,2017 Who is at risk ... content was last reviewed May 2016. Heart Valve Problems and Disease • Home • About Heart Valves • Heart Valve ...

  9. Living with Heart Valve Disease

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  10. What Causes Heart Valve Disease?

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  11. [Clinical analysis of robotic mitral valve repair].

    Science.gov (United States)

    Gao, Chang-Qing; Yang, Ming; Xiao, Cang-Song; Wang, Gang; Wang, Jia-Li; Wu, Yang; Wang, Yao

    2011-07-01

    To determine the safety and efficacy of robotic mitral valve repair using da Vinci S Surgical system. Method From January 2007 to April 2011, over 400 cases of robotic cardiac surgery have been performed, in which 60 patients with isolated mitral valve insufficiency underwent robotic mitral valve repair, including 42 male and 18 female patients with a mean age of (44 ± 13) years (ranging from 14 to 70 years). Forty-eight patients were in NYHA class I-II and 12 patients in class III. Fourteen patients were concomitant with atrial fibrillation. Surgery approach was achieved through 4 right chest ports with femoral perfusion and Chitwood aortic occlusion. Antegrade cold blood cardioplegia was administered directly via chest for myocardial protection. The transesophageal echocardiography was used intraoperatively to estimate the surgical results. All patients had successful valve repair including quadrangular resections, sliding plasties and chordal replacement. There was no conversion to median sternotomy. The mean cardiopulmonary bypass and arrested heart time were (132 ± 30) min and (88 ± 22) min. One patient had hemolysis after operation, and required mitral valve replacement. Echocardiographic follow-up revealed trace to mild regurgitation in 2 patients with a mean of (16 ± 9) months. Robotic mitral valve repair is safe and efficacious in the patients with isolated mitral valve insufficiency.

  12. Mitral valve prolapse

    Science.gov (United States)

    ... mitral valve prolapse is called "mitral valve prolapse syndrome," and includes: Chest pain (not caused by coronary artery disease or a heart attack) Dizziness Fatigue Panic attacks Sensation of feeling the heart beat ( palpitations ) ...

  13. Mitral Valve Stenosis

    Science.gov (United States)

    ... valve stenosis include: Rheumatic fever. A complication of strep throat, rheumatic fever can damage the mitral valve. Rheumatic ... children see your doctor for sore throats. Untreated strep throat infections can develop into rheumatic fever. Fortunately, strep ...

  14. Isolated Pulmonary Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Hatamizadeh

    2009-06-01

    Full Text Available Infective endocarditis is one of the most severe complications of parenteral drug abuse. The outstanding clinical feature of infective endocarditis in intravenous drug abusers is the high incidence of right-sided valve infection, and the tricuspid valve is involved in 60% to 70% of the cases. We herein report a case of isolated pulmonic valve infective endocarditis with a native pulmonary valve.

  15. A case of SAPIEN XT valve fallen into left ventricle during valve-in-valve transcatheter aortic valve implantation.

    Science.gov (United States)

    Koizumi, Shigeki; Ehara, Natsuhiko; Nishiya, Kenta; Koyama, Tadaaki

    2017-06-24

    Late transcatheter heart valve embolization is a rare but life-threatening complication of transcatheter aortic valve implantation. Surgical intervention is performed for most cases, but some cases were treated by valve-in-valve transcatheter aortic valve implantation. We describe a patient in whom a 29-mm Edwards SAPIEN XT valve migrated into the left ventricular outflow tract 41 days after the initial implantation. We tried to perform valve-in-valve transcatheter aortic valve implantation using a transfemoral approach. As soon as the second transcatheter heart valve touched the first implanted valve, it fell into the left ventricle. Immediate surgical intervention was required. The first valve was removed, and surgical aortic valve replacement was successfully performed. In conclusion, we should choose surgical aortic valve replacement for late transcatheter heart valve embolization. Even if we need to treat by catheter intervention, transapical approach may be better.

  16. Implementation of an enlarged model of the safety valves and relief in the plant integral model for the code RELAP/SCDAPSIM; Implementacion de un modelo ampliado de las valvulas de seguridad y alivio en el modelo integral de planta para el codigo RELAP/SCDAPSIM

    Energy Technology Data Exchange (ETDEWEB)

    Amador G, R.; Ortiz V, J.; Castillo D, R. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Hernandez L, E. J. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Fracc. La Virgen, 52149 Metepec, Estado de Mexico (Mexico); Galeana R, J. C. [Universidad del Valle de Mexico, Campus Toluca, Av. de Las Palmas 136, 52140 Metepec, Estado de Mexico (Mexico); Gutierrez, V. H., E-mail: rodolfo.amador@inin.gob.mx [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo 180, Col. Reynosa Tamaulipas, 02200 Mexico D. F. (Mexico)

    2013-10-15

    The present work refers to the implementation of a new model on the logic of the safety valves and relief in the integral model of the Nuclear Power Plant of Laguna Verde of the thermal-hydraulic compute code RELAP/SCDAPSIM Mod. 3.4. The new model was developed with the compute package SIMULINK-MATLAB and contemplates all the operation options of the safety valves and relief, besides including the availability options of the valves in all the operation ways and of blockage in the ways of relief and low-low. The implementation means the elimination of the old model of the safety valves and to analyze the group of logical variables, of discharge and available control systems to associate them to the model of package SIMULINK-MATLAB. The implementation has been practically transparent and 27 cases corresponding to a turbine discharge were analyzed with the code RELAP/SCDAPSIM Mod. 3.4. The results were satisfactory. (Author)

  17. Basis of valve operator selection for SMART

    Energy Technology Data Exchange (ETDEWEB)

    Kang, H. S.; Lee, D. J.; See, J. K.; Park, C. K.; Choi, B. S

    2000-05-01

    SMART, an integral reactor with enhanced safety and operability, is under development for use of the nuclear energy. The valve operator of SMART system were selected through the data survey and technical review of potential valve fabrication vendors, and it will provide the establishment and optimization of the basic system design of SMART. In order to establish and optimize the basic system design of SMART, the basis of selection for the valve operator type were provided based on the basic design requirements. The basis of valve operator selection for SMART will be used as a basic technical data for the SMART basic and detail design and a fundamental material for the new reactor development in the future.

  18. Comparative Matched Outcome of Evolut-R vs CoreValve Transcatheter Aortic Valve Implantation.

    Science.gov (United States)

    Landes, Uri; Bental, Tamir; Barsheshet, Alon; Assali, Abid; Vaknin Assa, Hana; Levi, Amos; Orvin, Katia; Kornowski, Ran

    2017-02-01

    The Evolut-R (Medtronic, Inc) is a transcatheter aortic valve implantation (TAVI) system that was built on the well-established foundation of Medtronic's CoreValve device platform. Although already in extensive clinical utilization, it is unknown if the Evolut-R improves TAVI outcomes. Herein, we compared TAVI outcomes of the Evolut-R and CoreValve devices. A propensity score 1:1 matching was conducted on 358 Evolut-R patients (n = 75) and CoreValve patients (n = 283). Thirty-day outcomes were compared using Valve Academic Research Consortium (VARC)-2 criteria. A combined 30-day endpoint including all-cause death, stroke, major vascular complication, major bleeding, implantation failure, paravalvular leak (PVL) ≥ moderate, and new pacemaker implantation was also tested. The final study group included 146 patients (73 Evolut-R; 73 CoreValve). Post matching, baseline characteristics were similar between the two groups. Mean patient age was 82 ± 6 years, mean STS score was 5.2 ± 3.8, 72% were female, and 17% were deemed frail. Implantation success reached 99% with Evolut-R and 94% with CoreValve (P=.10). Both groups had low periprocedural stroke/myocardial infarction/mortality rates and there was also no difference in 30-day vascular complications (P=.18), bleeding (P=.37), PVL (P=.24), and new pacemaker (P=.14). The combined outcome rate was 24% with Evolut-R and 37% with CoreValve (P=.10). This study indicates that the efficacy and safety of the self-expandable second-generation Evolut-R transcatheter valve is at least comparable with the first-generation CoreValve. The observed improved performance in correct positioning of a single valve and the numerically lower chance to suffer a combined TAVI endpoint needs further investigation.

  19. Heart Valve Diseases

    Science.gov (United States)

    Your heart has four valves. Normally, these valves open to let blood flow through or out of your heart, and then shut to keep it from flowing ... close tightly. It's one of the most common heart valve conditions. Sometimes it causes regurgitation. Stenosis - when ...

  20. Unnatural milieu: Thrombus after transcatheter mitral valve replacement.

    Science.gov (United States)

    Khan, Jaffar M; Lederman, Robert J

    2017-08-01

    What the article teaches Transcatheter heart valve thrombosis in the mitral position causes increased valve gradients, valve dysfunction, and symptoms, and may be associated with lack of therapeutic anticoagulation. How it will impact practice Anticoagulation with a vitamin K antagonist should be considered in all patients undergoing transcatheter mitral valve replacement. What new research/study would help answer the question posed Efficacy, optimal duration, and safety of anticoagulation therapy, balancing reduced thrombosis against increased bleeding risk, needs to be assessed in larger cohort studies and prospective trials. © 2017 Wiley Periodicals, Inc.

  1. Pressure locking and thermal binding of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, E.M.

    1996-12-01

    Pressure locking and thermal binding represent potential common mode failure mechanisms that can cause safety-related power-operated gate valves to fail in the closed position, thus rendering redundant safety-related systems incapable of performing their safety functions. Supplement 6 to Generic Letter 89-10, {open_quotes}Safety-Related Motor-Operated Gate Valve Testing and Surveillance,{close_quotes} provided an acceptable approach to addressing pressure locking and thermal binding of gate valves. More recently, the NRC has issued Generic Letter 95-07, {open_quotes}Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves,{close_quotes} to request that licensees take certain actions to ensure that safety-related power-operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions within the current licensing bases. Over the past two years, several plants in Region I determined that valves in certain systems were potentially susceptible to pressure locking and thermal binding, and have taken various corrective actions. The NRC Region I Systems Engineering Branch has been actively involved in the inspection of licensee actions in response to the pressure locking and thermal binding issue. Region I continues to maintain an active involvement in this area, including participation with the Office of Nuclear Reactor Regulation in reviewing licensee responses to Generic Letter 95-07.

  2. A systematic review on the safety and efficacy of percutaneous edge-to-edge mitral valve repair with the MitraClip system for high surgical risk candidates

    DEFF Research Database (Denmark)

    Munkholm-Larsen, Stine; Wan, Benjamin; Tian, David H

    2014-01-01

    BACKGROUND: MitraClip implantation has emerged as a viable option in high surgical risk patients with severe mitral regurgitation (MR). We performed the present systematic review to assess the safety and efficacy of the MitraClip system for high surgical risk candidates with severe organic and...... be implanted with reproducible safety and feasibility profile in this subgroup of patients. Further prospective trials with mid- to long-term follow-up are required....

  3. Main Oxidizer Valve Design

    Science.gov (United States)

    Addona, Brad; Eddleman, David

    2015-01-01

    A developmental Main Oxidizer Valve (MOV) was designed by NASA-MSFC using additive manufacturing processes. The MOV is a pneumatically actuated poppet valve to control the flow of liquid oxygen to an engine's injector. A compression spring is used to return the valve to the closed state when pneumatic pressure is removed from the valve. The valve internal parts are cylindrical in shape, which lends itself to traditional lathe and milling operations. However, the valve body represents a complicated shape and contains the majority of the mass of the valve. Additive manufacturing techniques were used to produce a part that optimized mass and allowed for design features not practical with traditional machining processes.

  4. 30 CFR 57.4603 - Closure of valves.

    Science.gov (United States)

    2010-07-01

    ... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Welding/cutting/compressed Gases § 57.4603 Closure of valves. To prevent accidental release of...

  5. 30 CFR 56.4603 - Closure of valves.

    Science.gov (United States)

    2010-07-01

    ... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Fire Prevention and Control Welding/cutting/compressed Gases § 56.4603 Closure of valves. To prevent accidental release of...

  6. Cryogenic Cam Butterfly Valve

    Science.gov (United States)

    McCormack, Kenneth J. (Inventor)

    2016-01-01

    A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

  7. Intelligent Flow Control Valve

    Science.gov (United States)

    Kelley, Anthony R (Inventor)

    2015-01-01

    The present invention is an intelligent flow control valve which may be inserted into the flow coming out of a pipe and activated to provide a method to stop, measure, and meter flow coming from the open or possibly broken pipe. The intelligent flow control valve may be used to stop the flow while repairs are made. Once repairs have been made, the valve may be removed or used as a control valve to meter the amount of flow from inside the pipe. With the addition of instrumentation, the valve may also be used as a variable area flow meter and flow controller programmed based upon flowing conditions. With robotic additions, the valve may be configured to crawl into a desired pipe location, anchor itself, and activate flow control or metering remotely.

  8. Modeling the Mitral Valve

    Science.gov (United States)

    Kaiser, Alexander

    2016-11-01

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

  9. Magnetic Check Valve

    Science.gov (United States)

    Morris, Brian G.; Bozeman, Richard J., Jr.

    1994-01-01

    Poppet in proposed check valve restored to closed condition by magnetic attraction instead of spring force. Oscillations suppressed, with consequent reduction of wear. Stationary magnetic disk mounted just upstream of poppet, also containing magnet. Valve body nonmagnetic. Forward pressure or flow would push poppet away from stationary magnetic disk so fluid flows easily around poppet. Stop in valve body prevents poppet from being swept away. When flow stopped or started to reverse, magnetic attraction draws poppet back to disk. Poppet then engages floating O-ring, thereby closing valve and preventing reverse flow. Floating O-ring facilitates sealing at low loads.

  10. Replaceable valve seat

    Science.gov (United States)

    Jordan, Raymond W.

    1992-01-01

    A valve with an O-ring, a disk seal, and a replaceable valve seat is presented. A groove in the bottom on the valve seat flange forms an inner and outer drip ledge with the inner and outer periphery of the flange. If leakage occurs at the valve seat O-ring, fluid droplets will form on the out drip ledge. If leakage occurs at the disk seal, fluid droplets will form on the inner drip ledge. A visual inspection of these drip ledges through an access port, or by a borescope placed in an inspection port, can discriminate between a leak which originates in the O-ring and a leak which originates in the disk seal. When conventional replaceable valve seats leak, fluid droplets form at the bottom on the valve seat. In the present invention, such a valve seat is modified by machining a groove on the bottom surface of the valve seat flange. This groove and the inner and outer surfaces of the flange intersect and form drip ledges. If leakage occurs at the valve seat seal, shown as an O-ring in the preferred embodiment, fluid droplets will form on the outer drip ledge. If leakage occurs at the valve disk seal, fluid droplets will form on the inner drip ledge. The drip ledges can be inspected either through an access port or by passing a borescope through a small inspection port in the valve case. Visual inspection of the bottom on the drip ledge will positively identify the required repair action.

  11. Valve reconstruction for congenital mitral valve disease.

    Science.gov (United States)

    Quinonez, Luis G; Del Nido, Pedro J

    2015-01-01

    The surgical treatment of mitral valve disease in children is a challenging problem. Mitral stenosis and regurgitation may occur in isolation or together. Mitral valve repair is almost always preferable to replacement. Mitral valve replacement is not an ideal alternative to repair due to limitations of size, growth, structural valve degeneration, anticoagulation and poor survival. Surgical repair of congenital mitral stenosis must address the multiple levels of obstruction, including resection of the supramitral ring, thinning of leaflets and mobilization of the subvalvular apparatus. Sometimes leaflet augmentation is required. Repair of mitral regurgitation in children may involve simple cleft closures, edge-to-edge repairs, triangular resections and annuloplasties. Techniques used in adults, such as annuloplasty bands or artificial chords, may not be appropriate for children. Overall, an imperfect mitral valve repair may be more acceptable than the negative consequences of a replacement in a child. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  12. SAFETY

    CERN Multimedia

    C. Schaefer and N. Dupont

    2013-01-01

      “Safety is the highest priority”: this statement from CERN is endorsed by the CMS management. An interpretation of this statement may bring you to the conclusion that you should stop working in order to avoid risks. If the safety is the priority, work is not! This would be a misunderstanding and misinterpretation. One should understand that “working safely” or “operating safely” is the priority at CERN. CERN personnel are exposed to different hazards on many levels on a daily basis. However, risk analyses and assessments are done in order to limit the number and the gravity of accidents. For example, this process takes place each time you cross the road. The hazard is the moving vehicle, the stake is you and the risk might be the risk of collision between both. The same principle has to be applied during our daily work. In particular, keeping in mind the general principles of prevention defined in the late 1980s. These principles wer...

  13. SAFETY

    CERN Document Server

    M. Plagge, C. Schaefer and N. Dupont

    2013-01-01

    Fire Safety – Essential for a particle detector The CMS detector is a marvel of high technology, one of the most precise particle measurement devices we have built until now. Of course it has to be protected from external and internal incidents like the ones that can occur from fires. Due to the fire load, the permanent availability of oxygen and the presence of various ignition sources mostly based on electricity this has to be addressed. Starting from the beam pipe towards the magnet coil, the detector is protected by flooding it with pure gaseous nitrogen during operation. The outer shell of CMS, namely the yoke and the muon chambers are then covered by an emergency inertion system also based on nitrogen. To ensure maximum fire safety, all materials used comply with the CERN regulations IS 23 and IS 41 with only a few exceptions. Every piece of the 30-tonne polyethylene shielding is high-density material, borated, boxed within steel and coated with intumescent (a paint that creates a thick co...

  14. Problem: Mitral Valve Regurgitation

    Science.gov (United States)

    ... State SELECT YOUR LANGUAGE Español (Spanish) 简体中文 (Traditional Chinese) 繁体中文 (Simplified Chinese) Tiếng Việt (Vietnamese) Healthy Living for Heart.org ... each time the left ventricle contracts. Watch an animation of mitral valve regurgitation A leaking mitral valve ...

  15. Problem: Heart Valve Regurgitation

    Science.gov (United States)

    ... State SELECT YOUR LANGUAGE Español (Spanish) 简体中文 (Traditional Chinese) 繁体中文 (Simplified Chinese) Tiếng Việt (Vietnamese) Healthy Living for Heart.org ... should be completely closed For example: Watch an animation of mitral valve regurgitation A leaking mitral valve ...

  16. Mitral Valve Prolapse

    Science.gov (United States)

    ... State SELECT YOUR LANGUAGE Español (Spanish) 简体中文 (Traditional Chinese) 繁体中文 (Simplified Chinese) Tiếng Việt (Vietnamese) Healthy Living for Heart.org ... valve syndrome . What happens during MVP? Watch an animation of mitral valve prolapse When the heart pumps ( ...

  17. Mitral Valve Disease

    Science.gov (United States)

    ... clots, but they also are less durable than mechanical valves and may need to be replaced in the future. Like mitral valve repair, replacement can be done minimally invasively or with traditional open heart surgery. Your medical team will discuss the advantages ...

  18. Transcatheter pulmonary valve replacement by hybrid approach using a novel polymeric prosthetic heart valve: proof of concept in sheep.

    Directory of Open Access Journals (Sweden)

    Ben Zhang

    Full Text Available Since 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach.We designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflets were made of 0.1-mm expanded polytetrafluoroethylene (ePTFE coated with phosphorylcholine. We chose glutaraldehyde-treated bovine pericardium valves as control. Pulmonary valve stents were implanted in situ by a hybrid transapical approach in 10 healthy sheep (8 for polymeric valve and 2 for bovine pericardium valve, weighing an average of 22.5±2.0 kg. Angiography and cardiac catheter examination were performed after implantation to assess immediate valvular functionality. After 4-week follow-up, angiography, echocardiography, computed tomography, and cardiac catheter examination were used to assess early valvular function. One randomly selected sheep with polymeric valve was euthanized and the explanted valved stent was analyzed macroscopically and microscopically.Implantation was successful in 9 sheep. Angiography at implantation showed all 9 prosthetic valves demonstrated orthotopic position and normal functionality. All 9 sheep survived at 4-week follow-up. Four-week follow-up revealed no evidence of valve stent dislocation or deformation and normal valvular and cardiac functionality. The cardiac catheter examination showed the peak-peak transvalvular pressure gradient of the polymeric valves was 11.9±5.0 mmHg, while that of two bovine pericardium valves were 11 and 17 mmHg. Gross morphology demonstrated good opening and closure characteristics. No thrombus or calcification was seen macroscopically

  19. Transcatheter aortic valve implantation for bicuspid aortic valve stenosis.

    Science.gov (United States)

    Hamdan, Ashraf; Kornowski, Ran

    2015-08-01

    In Preprocedural CT, patients with BAV have larger aortic annulus perimeters, and more calcified valves compared with TAV. In patients with BAV, self-expandable valves were under-expand and balloon-expandable valves have a trend toward increased rates of postimplantation AR grade. Self-expandable valves have higher postprocedural gradient in BAV compared with TAV. © 2015 Wiley Periodicals, Inc.

  20. Face-Sealing Butterfly Valve

    Science.gov (United States)

    Tervo, John N.

    1992-01-01

    Valve plate made to translate as well as rotate. Valve opened and closed by turning shaft and lever. Interactions among lever, spring, valve plate, and face seal cause plate to undergo combination of translation and rotation so valve plate clears seal during parts of opening and closing motions.

  1. Application of risk-based methods to inservice testing of check valves

    Energy Technology Data Exchange (ETDEWEB)

    Closky, N.B.; Balkey, K.R.; McAllister, W.J. [and others

    1996-12-01

    Research efforts have been underway in the American Society of Mechanical Engineers (ASME) and industry to define appropriate methods for the application of risk-based technology in the development of inservice testing (IST) programs for pumps and valves in nuclear steam supply systems. This paper discusses a pilot application of these methods to the inservice testing of check valves in the emergency core cooling system of Georgia Power`s Vogtle nuclear power station. The results of the probabilistic safety assessment (PSA) are used to divide the check valves into risk-significant and less-risk-significant groups. This information is reviewed by a plant expert panel along with the consideration of appropriate deterministic insights to finally categorize the check valves into more safety-significant and less safety-significant component groups. All of the more safety-significant check valves are further evaluated in detail using a failure modes and causes analysis (FMCA) to assist in defining effective IST strategies. A template has been designed to evaluate how effective current and emerging tests for check valves are in detecting failures or in finding significant conditions that are precursors to failure for the likely failure causes. This information is then used to design and evaluate appropriate IST strategies that consider both the test method and frequency. A few of the less safety-significant check valves are also evaluated using this process since differences exist in check valve design, function, and operating conditions. Appropriate test strategies are selected for each check valve that has been evaluated based on safety and cost considerations. Test strategies are inferred from this information for the other check valves based on similar check valve conditions. Sensitivity studies are performed using the PSA model to arrive at an overall IST program that maintains or enhances safety at the lowest achievable cost.

  2. GIANT PROSTHETIC VALVE THROMBUS

    Directory of Open Access Journals (Sweden)

    Prashanth Kumar

    2015-04-01

    Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.

  3. FLUID MECHANICS OF ARTIFICIAL HEART VALVES

    OpenAIRE

    Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P

    2009-01-01

    1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mecha...

  4. Mitral valve surgery - open

    Science.gov (United States)

    ... be able to store blood in the blood bank for transfusions during and after your surgery. Ask ... stroke. Valves made from human or animal tissue fail over time. They have an average lifespan of ...

  5. Valve Repair or Replacement

    Science.gov (United States)

    ... valve surgery can be done using a robot. Robotic surgery does not require a large incision in the ... The Texas Heart Institute has a robot. With robotic surgery, the surgeon has a control console, a side ...

  6. Aortic Valve Regurgitation

    Science.gov (United States)

    ... valves. Rheumatic fever. Rheumatic fever — a complication of strep throat and once a common childhood illness in the ... a severe sore throat, see a doctor. Untreated strep throat can lead to rheumatic fever. Fortunately, strep throat ...

  7. Current Status of Catheter-Based Treatment of Mitral Valve Regurgitation.

    Science.gov (United States)

    Gössl, Mario; Farivar, Robert S; Bae, Richard; Sorajja, Paul

    2017-05-01

    This review examines the current status of catheter-based repair and replacement for mitral valve disease, with a focus on native primary and secondary mitral valve regurgitation. Transcatheter mitral valve repair with the MitraClip®, with >40,000 performed procedures worldwide, has significantly advanced the field of transcatheter therapy for mitral valve regurgitation. Transcatheter mitral valve replacement remains in the early stages of development, mainly due to the complex anatomy and physiology of the mitral valve. Early feasibility studies in high-risk patients show promising procedural success, yet the adverse events require further study. Transcatheter therapies for mitral valve disease are the next endeavor for the pioneers of percutaneous structural heart disease interventions. Early results are encouraging but also show that further rigorous study is needed to determine efficacy and safety.

  8. Safety via Thermal Shutdown for Space Rated Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Li-ion battery safety has inspired many safety features from CID, to safety valves. However, none of the current features protect a battery from internal...

  9. How Is Heart Valve Disease Treated?

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  10. How Is Heart Valve Disease Diagnosed?

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  11. When a Heart Murmur Signals Valve Disease

    Science.gov (United States)

    ... Order AHA Brochures Your Heart Valve Surgery Your Mitral Valve Prolapse Innocent Heart Murmurs If Your Child Has a Congenital Heart Defect See all of our brochures Valve Disease Resources Patient Guide: Understanding Your Heart Valve Problem | ...

  12. Outcome With the Repositionable and Retrievable Boston Scientific Lotus Valve Compared With the Balloon-Expandable Edwards Sapien 3 Valve in Patients Undergoing Transfemoral Aortic Valve Replacement.

    Science.gov (United States)

    Seeger, Julia; Gonska, Birgid; Rottbauer, Wolfgang; Wöhrle, Jochen

    2017-06-01

    New generation devices for transfemoral aortic valve replacement were optimized on valve positioning and reduction of residual aortic regurgitation. We compared 30-day, 12-month, and 24-month outcomes of the Boston Scientific Lotus valve (Lotus) and the balloon-expandable Edwards Sapien 3 (ES3) valve. Primary end point was all-cause mortality or disabling stroke within 12 months. Between 2014 and 2016, 537 patients were enrolled at our center, and 202 patients received Lotus and 335 ES3. There was no residual moderate or severe aortic regurgitation. Rate of mild aortic regurgitation was lower with the repositionable and retrievable Lotus valve compared with the ES3. Rate of pacemaker implantation was significantly higher with the Lotus valve compared with the ES3 valve (36.1% versus 14.9%, P<0.01). Valve Academic Research Consortium-2 early safety end point at 30 days was 7.4% with both devices with no difference in all-cause mortality (Lotus, 1.9%; ES3, 1.8%; P=0.87), rate of disabling stroke (Lotus, 1.5%; ES3, 2.1%; P=0.62), or major vascular complications (Lotus, 2.9%; ES3, 2.4%; P=0.69). The primary end point at 12 months was similar between groups. In a propensity score-matched comparison, there was no difference in the primary end point within 12 months (Lotus, 15.5%; ES3, 18.6%; P=0.69) and 24 months (Lotus, 21.9%; ES3, 26.4%; P=0.49). Transfemoral aortic valve replacement with the ES3 and the Lotus were associated with similar 30-day, 12-month, and 24-month clinical outcomes. Need for permanent pacemaker implantation was significantly higher with the repositionable Lotus device. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02162069. © 2017 American Heart Association, Inc.

  13. Transcatheter Aortic Valve Replacement for Degenerative Bioprosthetic Surgical Valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John; Brecker, Stephen

    2012-01-01

    Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry....

  14. Resource utilization and procedure-related costs associated with transfemoral transcatheter aortic valve replacement.

    Science.gov (United States)

    Klein, Holger; Boleckova, Jana

    2017-06-01

    Transcatheter aortic valve implantation (TAVI) is an alternative to surgical valve replacement for patients with aortic stenosis (AS). This study assessed the impact of changing from a self-expandable (SE) valve to a balloon-expandable (BE) valve on healthcare resource use and procedural costs in a population of inoperable AS patients. In this retrospective single center study, data for 195 patients who received either an SE or a BE valve between 2010-2014 were collected. Procedural and post-procedural healthcare resource use and cost parameters were determined for the two groups. The study showed that overall procedural time, including time required by medical personnel, was significantly shorter for TAVI using a BE compared with an SE valve. Post-surgery, patients in the BE valve group had significantly shorter hospital stays than the SE valve group, including significantly fewer days spent in the intensive care unit (ICU). Additionally, trends towards reduced 30-day mortality, incidence of new permanent pacemaker implantation, and incidence of blood transfusion were observed in the BE valve group compared with the SE valve group. Finally, total procedural costs were 24% higher in the SE compared with the BE valve group. The BE valve data were acquired in a single year, whereas the SE valve data were from a 5-year period. However, a year-by-year analysis of patient characteristics and study outcomes for the SE valve group showed few significant differences over this 5-year period. Overall, changing from an SE to a BE valve for TAVI in patients with severe AS reduced both healthcare resource use and procedure-related costs, while maintaining patient safety. For healthcare providers, this could increase efficiency and capacity within the healthcare system, with the added advantage of reducing costs.

  15. [Totally robotic mitral valve surgery in 60 cases].

    Science.gov (United States)

    Yang, Ming; Gao, Chang-qing; Wang, Gang; Wang, Jia-li; Xiao, Cang-song; Wu, Yang

    2011-10-01

    To evaluate the safety and efficacy of robotic mitral valve surgery using da Vinci S system. We conducted a retrospective review of 60 robotic mitral surgeries from March 2007 to December 2010. Of the 60 patients, 44 underwent mitral valve repair and 16 received mitral valve replacement. The surgical approach was through 4 right chest ports with femoral and internal jugular vein cannulations. Transesophageal echocardiography was used intraoperatively to estimate the surgical results. None of the cases required a conversion to a median sternotomy. The mean cardiopulmonary bypass and cardiac arrest time was 132.2∓29.6 min and 88.1∓22.3 min for robotic mitral valve repair, and was 137.1∓21.9 min and 99.3∓17.4 min for robotic mitral valve replacement. Echocardiographic follow-up of all the patients revealed 3 cases of slight regurgitation in mitral valve repair group. In selected patients with mitral valve disease, robotic mitral surgery can be performed safely.

  16. Fluid and Structural Analysis of Large Butterfly Valve

    Science.gov (United States)

    Song, Xueguan; Wang, Lin; Park, Youngchul

    2008-10-01

    A butterfly valve of large diameter is commonly used as control equipments in applications where the inlet velocity is fast and the pressure is relatively high. Because of the size of the valve is too large, therefore it's too difficult to conduct the experiment in a laboratory. In this paper, the numerical simulation using commercial package-CFX and ANSYS was conducted. In order to do fluid analysis and structural analysis perfectly, large valve models are generated in three dimensions without much simplification, the result of fluid analysis is also fully coupled to the structural domain by the fluid-structural interface to provide an exacter initial condition. In addition to describe the flow patterns and to measure the performance coefficients when the valves with various open angles were used, the verification of the safety performance whether the valve could work normally at those conditions or not was conducted. Fortunately, the result shows this type valve is safe in a given inlet velocity of 3m/s, and it's not necessary to be strengthened anywhere, and if need be, the shape of valve disc can be optimized to reduce the weight of disc, and also to make the flow coefficient be closer to the suggested level.

  17. Diseases of the Tricuspid Valve

    Science.gov (United States)

    ... diseases of the tricuspid valve are regurgitation and stenosis. Tricuspid Regurgitation Tricuspid regurgitation is also called tricuspid ... the tricuspid valve may also be needed. Tricuspid Stenosis Tricuspid stenosis is a narrowing or blockage of ...

  18. Options for Heart Valve Replacement

    Science.gov (United States)

    ... valve: Aortic regurgitation , (sometimes referred to as aortic insufficiency) is another common valve problem that may require ... allows oxygenated blood to flow backwards into the lungs instead of continuing through the heart as it ...

  19. Variable Valve Actuation

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Gutterman; A. J. Lasley

    2008-08-31

    Many approaches exist to enable advanced mode, low temperature combustion systems for diesel engines - such as premixed charge compression ignition (PCCI), Homogeneous Charge Compression Ignition (HCCI) or other HCCI-like combustion modes. The fuel properties and the quantity, distribution and temperature profile of air, fuel and residual fraction in the cylinder can have a marked effect on the heat release rate and combustion phasing. Figure 1 shows that a systems approach is required for HCCI-like combustion. While the exact requirements remain unclear (and will vary depending on fuel, engine size and application), some form of substantially variable valve actuation is a likely element in such a system. Variable valve actuation, for both intake and exhaust valve events, is a potent tool for controlling the parameters that are critical to HCCI-like combustion and expanding its operational range. Additionally, VVA can be used to optimize the combustion process as well as exhaust temperatures and impact the after treatment system requirements and its associated cost. Delphi Corporation has major manufacturing and product development and applied R&D expertise in the valve train area. Historical R&D experience includes the development of fully variable electro-hydraulic valve train on research engines as well as several generations of mechanical VVA for gasoline systems. This experience has enabled us to evaluate various implementations and determine the strengths and weaknesses of each. While a fully variable electro-hydraulic valve train system might be the 'ideal' solution technically for maximum flexibility in the timing and control of the valve events, its complexity, associated costs, and high power consumption make its implementation on low cost high volume applications unlikely. Conversely, a simple mechanical system might be a low cost solution but not deliver the flexibility required for HCCI operation. After modeling more than 200 variations of

  20. Echocardiography of the mitral valve

    OpenAIRE

    Omran, A.S.; Arifi, A.A.; Mohamed, A.A.

    2010-01-01

    Mitral valve disease is the second most common valvular heart disease after the aortic valve worldwide. Mitral valve has historically been a structure of interest by pioneers in echocardiography. One of the earliest applications of echocardiography was in the diagnosis of valvular heart disease, particularly mitral stenosis. In this review we wish to take the reader through the structural and hemodynamic evaluation of the normal mitral valve.

  1. Valve thrombosis following transcatheter aortic valve implantation: a systematic review.

    Science.gov (United States)

    Córdoba-Soriano, Juan G; Puri, Rishi; Amat-Santos, Ignacio; Ribeiro, Henrique B; Abdul-Jawad Altisent, Omar; del Trigo, María; Paradis, Jean-Michel; Dumont, Eric; Urena, Marina; Rodés-Cabau, Josep

    2015-03-01

    Despite the rapid global uptake of transcatheter aortic valve implantation, valve trombosis has yet to be systematically evaluated in this field. The aim of this study was to determine the clinical characteristics, diagnostic criteria, and treatment outcomes of patients diagnosed with valve thrombosis following transcatheter aortic valve implantation through a systematic review of published data. Literature published between 2002 and 2012 on valve thrombosis as a complication of transcatheter aortic valve implantation was identified through a systematic electronic search. A total of 11 publications were identified, describing 16 patients (mean age, 80 [5] years, 65% men). All but 1 patient (94%) received a balloon-expandable valve. All patients received dual antiplatelet therapy immediately following the procedure and continued to take either mono- or dual antiplatelet therapy at the time of valve thrombosis diagnosis. Valve thrombosis was diagnosed at a median of 6 months post-procedure, with progressive dyspnea being the most common symptom. A significant increase in transvalvular gradient (from 10 [4] to 40 [12] mmHg) was the most common echocardiographic feature, in addition to leaflet thickening. Thrombus was not directly visualized with echocardiography. Three patients underwent valve explantation, and the remaining received warfarin, which effectively restored the mean transvalvular gradient to baseline within 2 months. Systemic embolism was not a feature of valve thrombosis post-transcatheter aortic valve implantation. Although a rare, yet likely under-reported complication of post-transcatheter aortic valve implantation, progressive dyspnea coupled with an increasing transvalvular gradient on echocardiography within the months following the intervention likely signifies valve thrombosis. While direct thrombus visualization appears difficult, prompt initiation of oral anticoagulation therapy effectively restores baseline valve function. Copyright © 2014

  2. Building valve amplifiers

    CERN Document Server

    Jones, Morgan

    2013-01-01

    Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling their first build or

  3. Danfos: Thermostatic Radiator Valves

    DEFF Research Database (Denmark)

    Gregersen, Niels; Oliver, James; Hjorth, Poul G.

    2000-01-01

    This problem deals with modelling the flow through a typical Danfoss thermostatic radiator valve.Danfoss is able to employ Computational Fluid Dynamics (CFD) in calculations of the capacity of valves, but an experienced engineer can often by rules of thumb "guess" the capacity, with a precision...... similar to the one achieved by the expensive and time-consuming CFD calculations. So CFD is only used in case of entirely new designs or where a very detailed knowledge of the flow is required. Even though rules of thumb are useful for those, who have developed them, Danfoss needs an objective and general...

  4. Edwards SAPIEN 3 valve.

    Science.gov (United States)

    Binder, Ronald K; Rodés-Cabau, Josep; Wood, David A; Webb, John G

    2012-09-01

    Building on the established success with the SAPIEN, SAPIEN XT and earlier prototypic transcatheter heart valves (THV) the newest balloon-expandable valve incorporates a number of new and enhanced features intended to reduce the risk of vascular injury, to reduce paravalvular regurgitation, and to facilitate rapid and accurate positioning and implantation. The SAPIEN 3 THV incorporates a cobalt chromium stent, bovine pericardial leaflets, and both an inner and new outer polyethylene terephthalate sealing cuff. The delivery system incorporates an active three-dimensional coaxial positioning catheter, and is compatible with a 14 Fr expandable sheath.

  5. Noncontacting valve-position indicator

    Science.gov (United States)

    Crovella, E. A.; Cummins, R. D.; Wada, J. M.

    1979-01-01

    Position of sealed valve or other movable part is indicated without penetrating housing. Flux from magnets connected to stem of hydraulic valve penetrates pressure wall and is sensed by Hall-effect transducer outside wall. When valve closes, moving stem and magnets, voltage from transducer decreases; thus, stem position is indicated without physical contact.

  6. Check valves with drop-shaped disk

    Energy Technology Data Exchange (ETDEWEB)

    1943-03-19

    This report discusses improvements possible with drop check valves. Up to the time of the report, the most important improvements had been: (1) lightening of the drop by hollowing it out, (2) reducing lift to reduce impact, (3) increasing clearance in the guide to minimize the danger of it getting stuck, (4) drilling of a safety hole which would indicate excessive wear of the housing by a leak. Other possibilities for the above improvements had produced the following conclusions: (1) a further lightening of the drop was found possible by milling out the halves with a milling cutter, by welding them together and thus eliminating the threaded portion, or by having the drop open on the bottom; (2) further reduction in lift was not found possible in most sizes, but for reduction of the impact effect by a cushion of oil or paste, the seating surface was widened as much as possible; (3) sticking of certain check valves caused by ferrous sulfide deposits could be solved by use of a certain bushing in the housing; (4) some plants favored and some disfavored the safety hole, but in general, plants were to service check valves and change them at such regular intervals as experience dictated; (5) the seat plate was no longer solid steel, but a welded piece.

  7. Tricuspid valve and percutaneous approach: No longer the forgotten valve!

    Science.gov (United States)

    Bouleti, Claire; Juliard, Jean-Michel; Himbert, Dominique; Iung, Bernard; Brochet, Eric; Urena, Marina; Dilly, Marie-Pierre; Ou, Phalla; Nataf, Patrick; Vahanian, Alec

    2016-01-01

    Tricuspid valve disease is mainly represented by tricuspid regurgitation (TR), which is a predictor of poor outcome. TR is usually secondary, caused by right ventricle pressure or volume overload, the leading cause being left-sided heart valve diseases. Tricuspid surgery for severe TR is recommended during left valve surgery, and consists of either a valve replacement or, most often, a tricuspid repair with or without prosthetic annuloplasty. When TR persists or worsens after left valvular surgery, redo isolated tricuspid surgery is associated with high mortality. In addition, a sizeable proportion of patients present with tricuspid surgery deterioration over time, and need a reintervention, which is associated with high morbi-mortality rates. In this context, and given the recent major breakthrough in the percutaneous treatment of aortic and mitral valve diseases, the tricuspid valve appears an appealing challenge, although it raises specific issues. The first applications of transcatheter techniques for tricuspid valve disease were valve-in-valve and valve-in-ring implantation for degenerated bioprosthesis or ring annuloplasty. Some concerns remain regarding prosthesis sizing, rapid ventricular pacing and the best approach, but these procedures appear to be safe and effective. More recently, bicuspidization using a transcatheter approach for the treatment of native tricuspid valve has been published, in two patients. Finally, other devices are in preclinical development. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  8. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, Jordan [Advanced Residential Integrated Energy Solutions Collaborative, New York, NY (United States); Ansanelli, Eric [Advanced Residential Integrated Energy Solutions Collaborative, New York, NY (United States)

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market.

  9. Aortic valve surgery - open

    Science.gov (United States)

    ... be able to store blood in the blood bank for transfusions during and after your surgery. Ask ... Mechanical heart valves do not fail often. However, blood clots can develop on them. If a blood clot forms, you may have a stroke. Bleeding can occur, ...

  10. Measurement of reed valve kinematics

    Directory of Open Access Journals (Sweden)

    Fenkl Michael

    2016-01-01

    Full Text Available The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  11. Technology Reinvestment Program/Advanced ``Zero Emission'' Control Valve (Phase II)

    Energy Technology Data Exchange (ETDEWEB)

    J. Napoleon

    1998-12-01

    The objectives of this effort are to determine, develop and demonstrate the feasibility of significantly reducing the cost and expanding the applications for a family of Advanced Zero Emissions Control Valves that meets the fugitive emissions requirements of the 1990 Amendments to the Clean Air Act. This program is a direct technology spin-off from the valve technology that is critical to the US Navy's Nuclear Powered Fleet. These zero emissions valves will allow the Hydrocarbon and Chemical Processing Industries, etc., to maintain their competitiveness and still meet environmental and safety requirements. Phase 2 is directed at refining the basic technologies developed during Phase 1 so that they can be more readily selected and utilized by the target market. In addition to various necessary certifications, the project will develop a full featured digital controller with ``smart valve'' growth capability, expanding valve sizes/applications and identifying valve materials to permit applications in severe operational environments.

  12. Micro-valve pump light valve display

    Science.gov (United States)

    Lee, Yee-Chun

    1993-01-01

    A flat panel display incorporates a plurality of micro-pump light valves (MLV's) to form pixels for recreating an image. Each MLV consists of a dielectric drop sandwiched between substrates, at least one of which is transparent, a holding electrode for maintaining the drop outside a viewing area, and a switching electrode from accelerating the drop from a location within the holding electrode to a location within the viewing area. The sustrates may further define non-wetting surface areas to create potential energy barriers to assist in controlling movement of the drop. The forces acting on the drop are quadratic in nature to provide a nonlinear response for increased image contrast. A crossed electrode structure can be used to activate the pixels whereby a large flat panel display is formed without active driver components at each pixel.

  13. Cyclonic valve test: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Andre Sampaio; Moraes, Carlos Alberto C.; Marins, Luiz Philipe M.; Soares, Fabricio; Oliveira, Dennis; Lima, Fabio Soares de; Airao, Vinicius [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Ton, Tijmen [Twister BV, Rijswijk (Netherlands)

    2012-07-01

    For many years, the petroleum industry has been developing a valve that input less shear to the flow for a given required pressure drop and this can be done using the cyclonic concept. This paper presents a comparison between the performances of a cyclonic valve (low shear) and a conventional globe valve. The aim of this work is to show the advantages of using a cyclonic low shear valve instead of the commonly used in the primary separation process by PETROBRAS. Tests were performed at PETROBRAS Experimental Center (NUEX) in Aracaju/SE varying some parameters: water cut; pressure loss (from 4 kgf/cm2 to 10 kgf/cm2); flow rates (30 m3/h and 45 m3/h). Results indicates a better performance of the cyclonic valve, if compared with a conventional one, and also that the difference of the performance, is a function of several parameters (emulsion stability, water content free, and oil properties). The cyclonic valve tested can be applied as a choke valve, as a valve between separation stages (for pressure drop), or for controlling the level of vessels. We must emphasize the importance to avoid the high shear imposed by conventional valves, because once the emulsion is created, it becomes more difficult to break it. New tests are being planned to occur in 2012, but PETROBRAS is also analyzing real cases where the applications could increase the primary process efficiency. In the same way, the future installations are also being designed considering the cyclonic valve usage. (author)

  14. Mechanical Valve Replacement: Early Results

    Directory of Open Access Journals (Sweden)

    Habib Cakir

    2012-02-01

    Full Text Available Aim: Valve diseases in developing countries like Turkey which often occur as a complication of rheumatic fever are a serious disease. Surgical treatment of valve diseases should be done before irreversible damage to the myocardium occurred. In this study, we aimed to present the early results of mechanical valve replacement operations. Method: A hundred patients with mechanical valve replacement surgery were retrospectively evaluated in Seyhan Application Center attached to our clinic between July 2007 and August 2011. Results: Fifty patients were male and 50 were women. The mean age of patients was 47.88 (18-78. Isolated aortic valve replacement (AVR was performed to 23 patients, isolated mitral valve replacement (MVR was 32, double valve replacement (AVR + MVR was 12, MVR + aortic valve valvuloplasty was 1, AVR + mitral kommissurotomi was 1, AVR + coronary artery bypass graft surgery (CABG was 17, MVR + CABG was 8, MVR + atrial septal defect closure was 2 and Bentall procedure.was 4 patients. In addition, ablation procedure was performed to 5 patients intraoperatively because of preoperative atrial fibrillation. Two patients (2 % died in early postoperative period. Conclusion: Mechanical prosthetic valves are used for surgical treatment of valve disease with low mortality and morbidity in a large group of patients like women that not to think to get pregnant, non advanced age group and patients have less risky for anticoagulation drug in our clinic. [Cukurova Med J 2012; 37(1.000: 49-54

  15. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John G; Bleiziffer, Sabine

    2014-01-01

    IMPORTANCE: Owing to a considerable shift toward bioprosthesis implantation rather than mechanical valves, it is expected that patients will increasingly present with degenerated bioprostheses in the next few years. Transcatheter aortic valve-in-valve implantation is a less invasive approach......, stroke, and New York Heart Association functional class. RESULTS: Modes of bioprosthesis failure were stenosis (n = 181 [39.4%]), regurgitation (n = 139 [30.3%]), and combined (n = 139 [30.3%]). The stenosis group had a higher percentage of small valves (37% vs 20.9% and 26.6% in the regurgitation...... and combined groups, respectively; P = .005). Within 1 month following valve-in-valve implantation, 35 (7.6%) patients died, 8 (1.7%) had major stroke, and 313 (92.6%) of surviving patients had good functional status (New York Heart Association class I/II). The overall 1-year Kaplan-Meier survival rate was 83...

  16. Performance Characteristics of an Isothermal Freeze Valve

    Energy Technology Data Exchange (ETDEWEB)

    Hailey, A.E.

    2001-08-22

    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  17. Tricuspid Valve Replacement, Mechnical vs. Biological Valve, Which Is Better?

    Directory of Open Access Journals (Sweden)

    Haitham Akram Altaani

    2013-06-01

    Full Text Available Background: The initial trial in tricuspid surgery is repair; however, replacement is done whenever the valve is badly diseased. Tricuspid valve replacement comprises 1.7% of all tricuspid valve surgeries. Materials and Methods: The present retrospective study was performed using the medical records of 21 cases who underwent tricuspid valve replacement from January 2002 until the end of December 2010. The mean age of the participants was 52.3±8.8 years and 66.7% were females. In addition, tricuspid valve replacement was associated with mitral valve surgery, aortic valve surgery, and both in 14.3%, 4.8%, and 33.3% of the cases, respectively. Yet, isolated tricuspid valve replacement and redo surgery were performed in 10 cases (47.6% and 8 cases (38.1%, respectively. Besides, trial of repair was done in 14 cases (66.7%. Moreover, biological and mechanical valves were used in 76.2% and 23.8% of the patients, respectively. Results: According to the results, early mortality was 23.8% and one year survival was 66.7%. Moreover, early mortality was caused by right ventricular failure, multiorgan failure, medistinitis, and intracerbral bleeding in 42%, 28.6%, 14.3%, and 14.3% of the cases, respectively. In addition, 57.1% of the deaths had occurred in the cases where the biological valve was used, while 42.9% of the deaths had taken place where the mechanical one was utilized. Conclusions: The patients who require tricuspid valve replacement are usually high risk surgical candidates with early and long term mortality. The findings of the current study showed no significant hemodynamic difference between mechanical and biological valves.

  18. Thermo-electric valve

    Science.gov (United States)

    Chamberland, R. R.; Stanland, A. J.

    1985-02-01

    A thermo-electric valve is described for scuttling floating devices comprising, a cylindrical sleeve affixed to and passing through a bulkhead separating a pressurized medium on one side from a lower pressure space on the other side, a piston moveably mounted within the sleeve bore and exposed to the pressurized medium having a portion thereof blocking the sleeve bore, an O-ring sealing the gap between the piston head and the sleeve bore, a fully compressed spring pressing against the piston, a rigid dielectric washer and a low power resistor holding the piston against the spring. In operation a low current is passed through the resistor, disintegrating it and releasing the spring's stored energy. This actuates the valve by expelling the piston which allows the pressurized fluid or gas to enter the lower pressure space.

  19. Patents and heart valve surgery--I: mechanical valves.

    Science.gov (United States)

    Cheema, Faisal H; Hussain, Nasir; Kossar, Alexander P; Polvani, Gianluca

    2013-04-01

    Valvular heart disease, inherited or acquired, affects more than 5 million Americans yearly. Whereas medical treatment is beneficial in the initial stages of valvular heart disease, surgical correction provides symptomatic relief and long-term survival benefits. Surgical options include either repair or replacement using mechanical or bio-prosthetic valves. Patient age and the post-operative need for anticoagulation therapy are major determinants of the choice between use of mechanical or bio-prosthetic valves. Since the first mechanical valves were made available several decades ago, the incorporation of increasingly sophisticated materials and methodologies has led to substantial improvements in the valve design, and has catalyzed a parallel increase in the amount of patents issued for these emerging technologies. In this paper, we have chronologically reviewed such patents, briefly discussed various challenges that mechanical heart valve implementation is faced with and finally reviewed some of the strategies employed to overcome such obstacles. An ideal prosthetic heart valve would comprehensively mimic the natural hemodynamics and physiology of the native heart valve. Additionally, such a valve would be easily implantable, associated with a minimal risk of thrombosis and thus need for anti-coagulation, and with a proven long-term durability. With cutting edge technological advancements in the recent times, the ongoing innovative and collaborative efforts of physicians, scientists, and engineers will not seize until an ideal mechanical heart valve becomes a reality.

  20. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A

    2008-01-01

    countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early...... and southern European countries. Imbalances in the prevalence of rheumatic heart disease, health resource availability and variations in surgical practice throughout Europe might be possible etiological causes....

  1. MSSV Modeling for Wolsong-1 Safety Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Bok Ja; Choi, Chul Jin; Kim, Seoung Rae [KEPCO EandC, Daejeon (Korea, Republic of)

    2010-10-15

    The main steam safety valves (MSSVs) are installed on the main steam line to prevent the overpressurization of the system. MSSVs are held in closed position by spring force and the valves pop open by internal force when the main steam pressure increases to open set pressure. If the overpressure condition is relieved, the valves begin to close. For the safety analysis of anticipated accident condition, the safety systems are modeled conservatively to simulate the accident condition more severe. MSSVs are also modeled conservatively for the analysis of over-pressurization accidents. In this paper, the pressure transient is analyzed at over-pressurization condition to evaluate the conservatism for MSSV models

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

    Directory of Open Access Journals (Sweden)

    Fadi E Shamoun

    2015-01-01

    Full Text Available 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.

  3. Anterior Urethral Valves

    Directory of Open Access Journals (Sweden)

    Vidyadhar P. Mali

    2006-07-01

    Full Text Available We studied the clinical presentation and management of four patients with anterior urethral valves; a rare cause of urethral obstruction in male children. One patient presented antenatally with oligohydramnios, bilateral hydronephrosis and bladder thickening suggestive of an infravesical obstruction. Two other patients presented postnatally at 1 and 2 years of age, respectively, with poor stream of urine since birth. The fourth patient presented at 9 years with frequency and dysuria. Diagnosis was established on either micturating cystourethrogram (MCU (in 2 or on cystoscopy (in 2. All patients had cystoscopic ablation of the valves. One patient developed a postablation stricture that was resected with an end-to-end urethroplasty. He had an associated bilateral vesicoureteric junction (VUJ obstruction for which a bilateral ureteric reimplantation was done at the same time. On long-term follow-up, all patients demonstrated a good stream of urine. The renal function is normal. Patients are continent and free of urinary infections. Anterior urethral valves are rare obstructive lesions in male children. The degree of obstruction is variable, and so they may present with mild micturition difficulty or severe obstruction with hydroureteronephrosis and renal impairment. Hence, it is important to evaluate the anterior urethra in any male child with suspected infravesical obstruction. The diagnosis is established by MCU or cystoscopy and the treatment is always surgical, either a transurethral ablation or an open resection. The long-term prognosis is good.

  4. Industry activities to improve valve performance

    Energy Technology Data Exchange (ETDEWEB)

    Callaway, C.

    1996-12-01

    Motor-operated valve issues refuse to go away. For over a decade the industry and the NRC have been focusing extraordinary resources on assuring these special components operate when called upon. Now that industry has fixed the design deficiencies, it is focusing on assuring that they perform their safety function within the current licensing basis for the remainder of plant life. NEI supported the efforts by ASME to develop OMN-1 and was encouraged that the industry and the NRC worked together to develop risk and performance based approaches to maintain MOV performance.

  5. Optothermally actuated capillary burst valve

    Science.gov (United States)

    Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders; Marie, Rodolphe

    2017-04-01

    We demonstrate the optothermal actuation of individual capillary burst valves in an all-polymer microfluidic device. The capillary burst valves are realised in a planar design by introducing a fluidic constriction in a microfluidic channel of constant depth. We show that a capillary burst valve can be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett. 10, 826-832 (2010)]. An individual valve is burst by focusing the laser in its vicinity. We demonstrate the capture of single polystyrene 7 μm beads in the constriction triggered by the bursting of the valve.

  6. Update of transcatheter valve treatment.

    Science.gov (United States)

    Liu, Xian-bao; Wang, Jian-an

    2013-08-01

    Transcatheter valve implantation or repair has been a very promising approach for the treatment of valvular heart diseases since transcatheter aortic valve implantation (TAVI) was successfully performed in 2002. Great achievements have been made in this field (especially TAVI and transcatheter mitral valve repair--MitraClip system) in recent years. Evidence from clinical trials or registry studies has proved that transcatheter valve treatment for valvular heart diseases is safe and effective in surgical high-risk or inoperable patients. As the evidence accumulates, transcatheter valve treatment might be an alterative surgery for younger patients with surgically low or intermediate risk valvular heart diseases in the near future. In this paper, the updates on transcatheter valve treatment are reviewed.

  7. Mitral valve repair versus replacement

    Science.gov (United States)

    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

  8. [Effect of transcatheter aortic valve replacement using Venus-A valve for treating patients with severe aortic stenosis].

    Science.gov (United States)

    Song, G Y; Wang, M Y; Wang, Y; Liu, X B; Feng, Y; Kong, X Q; Wu, Y J

    2017-10-24

    Objective: To evaluate the effect of transcatheter aortic valve replacement(TAVR) using Venus-A valve for treating patients with severe aortic stenosis. Methods: In this prospective study, 101 consecutive severe aortic stenosis patients with high surgical risk(Society of Thoracic Surgeon(STS) score ≥4%) or at prohibitive surgical risk were enrolled from 5 academic cardiovascular centers in China(Fuwai hospital, the second affiliated hospital of Zhejiang university school of medicine, West China hospital of Sichuan university, the first affiliated hospital of Nanjing medical university, Ruijin hospital of Shanghai Jiaotong university school of medicine) from September 2012 to January 2015, and Venus-A valves were used in TAVR for these patients. The primary endpoints were death from any cause and major stroke in 1 year. The secondary endpoints included efficacy and safety of TAVR in 1 year. Results: TAVR success rate was 97.9%(98/101), and 3 patients were transferred to receive surgical AVR. There were 85 patients using 1 Venus-A valve, and 13 patients underwent valve-in-valve implantation using 2 Venus-A valves. There were 1 case(1.0%) of stroke, 2 cases(2.0%)of acute myocardial infarction, 5 cases(5.0%) of pericardial effusion, 6 cases(5.9%) of severe vascular complication, and 2 cases(2.0%) of death after 7 days of TAVR. Meanwhile, aortic pressure gradient derived from echocardiography was significantly reduced when compared with pre-procedure level(11(8, 15) mmHg (1 mmHg=0.133 kPa) vs. 59(45, 71)mmHg, PVenus-A valve for treating patients with severe aortic stenosis is effective and safe in the early and medium term post procedure.

  9. System of monitoring and diagnosis of motor-operated valves using fuzzy logic; Sistema de monitoracao e diagnostico de valvula moto-operada, utilizando logica nebulosa

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Alvaro Luiz G.; Silva, Aucyone A. da [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Silva, Aucyone A. da; Andrade, Marco Tulio C. de [Sao Paulo Univ., SP (Brazil). Escola Politecnica

    2000-07-01

    The issue about of reliability of components, more specifically motor-operated valves related to safety systems, has became one of the most important factors to be investigated in nuclear power plants. This work has presented a direct application of fuzzy logic in monitoring and diagnosis systems of motor-operated valves used in nuclear power plants safety systems, based on motor signature power analysis during the operation of opening and closure of valve.

  10. Latest design of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  11. Investigation of valve failure problems in LWR power plants

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-04-01

    An analysis of component failures from information in the computerized Nuclear Safety Information Center (NSIC) data bank shows that for both PWR and BWR plants the component category most responsible for approximately 19.3% of light water reactor (LWR) power plant shutdowns. This investigation by Burns and Roe, Inc. shows that the greatest cause of shutdowns in LWRs due to valve failures is leakage from valve stem packing. Both BWR plants and PWR plants have stem leakage problems (BWRs, 21% and PWRs, 34%).

  12. Control of the valve system of multicyclic bed testers

    Energy Technology Data Exchange (ETDEWEB)

    Lopatkin, O.P.; Varlamov, P.S.

    1980-01-01

    It has been established that in testing beds with the help of multicyclic testers in twisted wells, the height of lifting the pipes for closure of the valve should be determined with regard for the resistance forces during movement of the drilling pipe string. A plan is presented for the pipe shaft with lowered drilling string after installation of the packer. The technique developed in the North Caucasus Scientific Research and Planning Institute of the Oil Industry will make it possible to determine for deep twisted wells the height of lifting of the string drilling pipes needed to close the safety valve of the multicyclic bed tester.

  13. Theoretical seismic analysis of butterfly valve for nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang Uk; Ahn, Jun Tae; Han, Seung Ho [Donga Univ., Busan (Korea, Republic of); Lee, Kyung Chul [Dukwon Valve Co., Ltd., Busan (Korea, Republic of)

    2012-09-15

    Valves are one of the most important components of a pipeline system in a nuclear power plant, and it is important to ensure their structural safety under seismic loads. A crucial aspect of structural safety verification is the seismic qualification, and therefore, an optimal shape design and experimental seismic qualification is necessary in case the configuration of the valve parts needs to be modified and their performance needs to be improved. Recently, intensive numerical analyses have been preformed before the experimental verification in order to determine the appropriate design variables that satisfy the performance requirements under seismic loads. In this study, static and dynamic numerical structural analyses of a 200A butterfly valve for a nuclear power plant were performed according to the KEPIC MFA. The result of static analysis considering an equivalent static load under SSE condition gave an applied stress of 135MPa. In addition, the result of dynamic analysis gave an applied stress of 183MPa, where the CQC method using response spectrums was taken into account. These values are under the allowable strength of the materials used for manufacturing the butterfly valve, and therefore, its structural safety satisfies the requirements of KEPIC MFA.

  14. Prosthetic valve endocarditis after transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Olsen, Niels Thue; De Backer, Ole; Thyregod, Hans G H

    2015-01-01

    BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an advancing mode of treatment for inoperable or high-risk patients with aortic stenosis. Prosthetic valve endocarditis (PVE) after TAVI is a serious complication, but only limited data exist on its incidence, outcome, and procedural...

  15. Overview of Prevention for Water Hammer by Check Valve Action in Nuclear Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dayong; Yoon, Hyungi; Seo, Kyoungwoo; Kim, Seonhoon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Water hammer can cause serious damage to pumping system and unexpected system pressure rise in the pipeline. In nuclear reactor, water hammer can influence on the integrity of safety related system. Water hammer in nuclear reactor have been caused by voiding in normally water-filled lines, steam condensation line containing both steam and water, as well as by rapid check valve action. Therefore, this study focuses on the water hammer by check valve among the sources of water hammer occurrence and suggests proper methodology for check valve type selection against water hammer. This study focuses on the water hammer by check valve action among the sources of water hammer occurrence and suggests proper methodology for check valve type selection against water hammer. If the inadvertent pump trip or pipe rupture in high velocity and pressure pipe is predicted, the fast response check valve such as tiled disc, dual disc and nozzle check valve should be installed in the system. If the inadvertent pump trip or pipe rupture in very high velocity and pressure pipe and excessively large revered flow velocity are predicted, the very slowly closing check valve such as controlled closure check valve should be installed in the system.

  16. A Study of System Pressure Transients Generated by Isolation Valve Open/Closure in Orifice Manifold

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. [KEPCO, Daejeon (Korea, Republic of); Bae, S. W.; Kim, J. I.; Park, S. J. [KHNP, Abu Dhabi (United Arab Emirates)

    2016-05-15

    In this study, we explore the effects of pressure transients on peak and minimal pressures caused by the actuation of isolation valve and control valve reacting to the combined orifice operation of orifice manifold with motor-operated valve installed in the rear of the orifice. We then use the collected data to direct our effort towards cause analysis and propose improvements to efficiency and safety of operation. This formation is used to by domestic and foreign nuclear power plants as a mean to control flow rate, producing required flow rate jointly together by combination of the orifices. No significant impacts on the internals of manifold orifice due to peak pressure has been observed, although chance of cavitation at the outlet of control valve is significant. Considering the peak pressure, as well as minimum pressure occurs in low flow rate conditions, the pressure transient is more so affected by the characteristics (modified equal percentage) of control valve. Isolation valve of the orifice and control valve operate organically, therefore stroke time for valves need to be applied in order for both valves to cooperatively formulate an optimized operation.

  17. In vitro evaluation of implantation depth in valve-in-valve using different transcatheter heart valves.

    Science.gov (United States)

    Simonato, Matheus; Azadani, Ali N; Webb, John; Leipsic, Jonathon; Kornowski, Ran; Vahanian, Alec; Wood, David; Piazza, Nicolo; Kodali, Susheel; Ye, Jian; Whisenant, Brian; Gaia, Diego; Aziz, Mina; Pasala, Tilak; Mehilli, Julinda; Wijeysundera, Harindra C; Tchetche, Didier; Moat, Neil; Teles, Rui; Petronio, Anna Sonia; Hildick-Smith, David; Landes, Uri; Windecker, Stephan; Arbel, Yaron; Mendiz, Oscar; Makkar, Raj; Tseng, Elaine; Dvir, Danny

    2016-09-18

    Transcatheter heart valve (THV) implantation in failed bioprosthetic valves (valve-in-valve [ViV]) offers an alternative therapy for high-risk patients. Elevated post-procedural gradients are a significant limitation of aortic ViV. Our objective was to assess the relationship between depth of implantation and haemodynamics. Commercially available THVs used for ViV were included in the analysis (CoreValve Evolut, SAPIEN XT and the Portico valve). THVs were implanted in small surgical valves (label size 19 mm) to simulate boundary conditions. Custom-mounted pulse duplicators registered relevant haemodynamic parameters. Twenty-eight experiments were performed (13 CVE, 5 SXT and 10 Portico). Ranges of depth of implantation were: CVE: -1.2 mm to 15.7 mm; SXT: -2.2 mm to 7.5 mm; Portico: 1.4 mm to 12.1 mm. Polynomial regression established a relationship between depth of implantation and valvular mean gradients (CVE: p<0.001; SXT: p=0.01; Portico: p=0.002), as well as with EOA (CVE: p<0.001; SXT: p=0.02; Portico valve: p=0.003). In addition, leaflet coaptation was better in the high implantation experiments for all valves. The current comprehensive bench testing assessment demonstrates the importance of high device position for the attainment of optimal haemodynamics during aortic ViV procedures.

  18. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  19. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy...

  20. Butterfly valve apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Ball, L.K.; Hines, M.U.; Miller, T.L.

    1990-10-23

    This patent describes a method of controlling fluid flow in a duct, and duct having a wall bounding a flow path wherein flows the fluid. It comprises: disposing a plate-like valve member in the flow path, which valve member is pivotally movable about an axis generally transverse to the duct between a first position transverse to and closing the flow path and a second position generally parallel with the flow path to open and allow fluid flow therein: transecting the valve member with the pivot axis to define with respect to direction of the fluid flow in the duct and pivotal movement of the valve member toward the open position an upstream valve member wing and a downstream valve member wing each substantially equal in area: increasing the effective area of the valve member upon which the fluid flow exerts fluid dynamic flow forces; and pivoting the valve member toward the second open position thereof in response to the increase of effective area.

  1. The spin-valve transistor

    NARCIS (Netherlands)

    Anil Kumar, P.S.; Lodder, J.C.

    2000-01-01

    The spin-valve transistor is a magnetoelectronic device that can be used as a magnetic field sensor. It has a ferromagnet-semiconductor hybrid structure. Using a vacuum metal bonding technique, the spin-valve transistor structure Si/Pt/NiFe/Au/Co/Au/Si is obtained. It employs hot electron transport

  2. Mechanical Valve Replacement: Early Results

    Directory of Open Access Journals (Sweden)

    Habib Cakir

    2012-03-01

    Conclusion: Mechanical prosthetic valves are used for surgical treatment of valve disease with low mortality and morbidity in a large group of patients like women that not to think to get pregnant, non advanced age group and patients have less risky for anticoagulation drug in our clinic. [Cukurova Med J 2012; 37(1: 49-54

  3. Supervision system for safety valves and operative metering station of the Yacuiba-Rio Grande Gas Pipeline; Sistema de supervisao para valvulas de seguranca e estacoes de medicao operativas do gasoducto Yacuiba-Rio Grande

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, Fernando; Marques, Ailton [Transierra S.A., La Paz (Bolivia)

    2005-07-01

    One of the most critical points for the opportune intervention that compromises the operations of TRANSIERRA S.A., is the integrity of the facilities, the adjacent communities and the environment are the Shut Down Valves (SDV) of the GASYRG Gas pipeline. The GASYRG (Yacuiba Rio Grande Gas pipeline) with an extension of 432 Km and a Pipeline diameter of 32 inches presents 2 Receipt Stations, 1 Delivery Point and 11 Line Valves. The pipeline operation is made by satellite and SCADA applications; it is supervised and controlled on-line at the points of delivery and receipt; monitoring of the SDV's was left aside; because of this it was necessary to develop a Remote Supervision System. This system combines remote devices with the Control Philosophy of Report By-Exception, Low Orbit Satellite System, Internet application and Intranet. The mentioned information is sent in e-mail format to a Satellite Teleport located in London, England. The process information is sent via Internet to TRANSIERRA's SCADA Servers for its interpretation and display in the HMI of the GASYRG supervisory system. (author)

  4. Cracking a tricuspid perimount bioprosthesis to optimize a second transcatheter sapien valve-in-valve placement.

    Science.gov (United States)

    Brown, Stephen C; Cools, Bjorn; Gewillig, Marc

    2016-09-01

    Bioprosthetic valves degenerate over time. Transcatheter valve-in-valve procedures have become an attractive alternative to surgery. However, every valve increasingly diminishes the diameter of the valvar orifice. We report a 12-year-old female who had a previous transcatheter tricuspid valve-in-valve procedure; cracking the ring of a Carpentier Edwards Perimount valve by means of an ultrahigh pressure balloon allowed implantation of a further larger percutaneous valve. The advantage of this novel approach permits enlarging the inner valve diameter and may facilitate future interventions and prolong time to surgery. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    Artificial heart valves are engineered devices used for replacing diseased or damaged natural valves of the heart. Most commonly used for replacement are mechanical heart valves and biological valves. This paper briefly outlines the evolution, designs employed, materials being used,. and important factors that affect the ...

  6. Transcatheter, valve-in-valve transapical aortic and mitral valve implantation, in a high risk patient with aortic and mitral prosthetic valve stenoses

    Directory of Open Access Journals (Sweden)

    Harish Ramakrishna

    2015-01-01

    Full Text Available Transcatheter valve implantation continues to grow worldwide and has been used principally for the nonsurgical management of native aortic valvular disease-as a potentially less invasive method of valve replacement in high-risk and inoperable patients with severe aortic valve stenosis. Given the burden of valvular heart disease in the general population and the increasing numbers of patients who have had previous valve operations, we are now seeing a growing number of high-risk patients presenting with prosthetic valve stenosis, who are not potential surgical candidates. For this high-risk subset transcatheter valve delivery may be the only option. Here, we present an inoperable patient with severe, prosthetic valve aortic and mitral stenosis who was successfully treated with a trans catheter based approach, with a valve-in-valve implantation procedure of both aortic and mitral valves.

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

    Science.gov (United States)

    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.

  8. Thermostatic Radiator Valve Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, J. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States); Ansanelli, E. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States)

    2015-01-01

    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market. In this project, the ARIES team sought to better understand the current usage of TRVs by key market players in steam and hot water heating and to conduct limited experiments on the effectiveness of new and old TRVs as a means of controlling space temperatures and reducing heating fuel consumption. The project included a survey of industry professionals, a field experiment comparing old and new TRVs, and cost-benefit modeling analysis using BEopt™ (Building Energy Optimization software).

  9. Valve monitoring and evaluation method; Un moderno diagnostico de valvulas y metodo de evaluacion

    Energy Technology Data Exchange (ETDEWEB)

    Kradepohl, P.

    2001-07-01

    With the valve monitoring and evaluation method presented here tools are available to optimise the operation of power plants furthermore. With ADAM a self-contained service conception for condition oriented maintenance of valves and actuators is at the operator's disposal. It includes efficient test and diagnosis systems for online and offline use as well as the affilated engineering procedures and the contribution to the condition evaluating process. Gathered knowledge about the functional behaviour of valves and actuators in detail leads to remarkably increased safety and availability combined with a lucrative reduction of maintenance efforts. (Author)

  10. Expanding TAVI options: elective rotational atherectomy during trans-catheter aortic valve implantation

    Energy Technology Data Exchange (ETDEWEB)

    Piccoli, Anna; Lunardi, Mattia; Ariotti, Sara; Ferrero, Valeria; Vassanelli, Corrado; Ribichini, Flavio, E-mail: flavio.ribichini@univr.it

    2015-01-15

    Summary: Aortic valve stenosis (AVS) in the elderly is frequently associated to coronary artery disease (CAD). In patients with significant coronary stenosis surgical valve replacement is associated to coronary bypass grafting, but whether coronary angioplasty is needed in patients receiving trans-catheter aortic valve implantation (TAVI) is unknown. Given the frequent complexity of CAD in the elderly with calcific AVS, rotational atherectomy (RA) may be needed in some cases. No data are available about feasibility and safety of RA during TAVI. The need for myocardial revascularization in TAVI candidates is discussed, and a series of RA cases performed during TAVI is described.

  11. Management of a locked Strata valve.

    Science.gov (United States)

    Bullivant, Kelly J; Mitha, Alim P; Hamilton, Mark G

    2009-04-01

    The PS Medical Strata valve is a programmable shunt valve used in the treatment of hydrocephalus that allows for noninvasive changes in the pressure setting using a magnet. The Strata valve is sensitive to magnetic fields, and reprogramming is frequently necessary after MR imaging. A known but rare complication of the Strata valve is that the rotor can become locked, causing shunt malfunction. This complication can only occur in a first generation Strata valve.

  12. 3D Printed Multimaterial Microfluidic Valve

    OpenAIRE

    Keating, Steven J.; Gariboldi, Maria Isabella; Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deform...

  13. Clinical Implication of Transaortic Mitral Pannus Removal During Repeat Cardiac Surgery for Patients With Mechanical Mitral Valve.

    Science.gov (United States)

    Park, Byungjoon; Sung, Kiick; Park, Pyo Won

    2018-01-25

    This study aimed to evaluate the safety and feasibility of transaortic mitral pannus removal (TMPR).Methods and Results:Between 2004 and 2016, 34 patients (median age, 57 years; 30 women) with rheumatic disease underwent pannus removal on the ventricular side of a mechanical mitral valve through the aortic valve during reoperation. The median time interval from the previous surgery was 14 years. TMPR was performed after removal of the mechanical aortic valve (n=21) or diseased native aortic valve (n=11). TMPR was performed in 2 patients through a normal aortic valve. The mitral transprosthetic mean pressure gradient (TMPG) was ≥5 mmHg in 11 patients, including 3 with prosthetic valve malfunction. Prophylactic TMPR was performed in 23 patients. There were no early deaths. Concomitant operations included 22 tricuspid valve surgeries (13 replacements, 15 repairs) and 32 aortic valve replacements (24 repeats, 8 primary). The mean gradient in patients who had mitral TMPG ≥5 mmHg was significantly decreased from 6.46±1.1 to 4.37±1.17 mmHg at discharge (Pvalve malfunction was apparent on last echocardiography. TMPR is a safe and effective procedure for patients with malfunction or stenosis of a mechanical mitral valve and may be considered an alternative approach in patients with pannus overgrowth in such valves.

  14. Treatment of Aortic, Mitral and Tricuspid Structural Bioprosthetic Valve Deterioration Using the Valve-in-Valve Technique.

    Science.gov (United States)

    Codner, Pablo; Assali, Abid; Vaknin-Assa, Hana; Shapira, Yaron; Orvin, Katia; Sharony, Ram; Sagie, Alexander; Kornowski, Ran

    2015-05-01

    The percutaneous approach for a failed bioprosthetic valve is an emerging alternative to redo-valve surgery in patients at high surgical risk. The study aim was to describe the treatment of patients with structural bioprosthetic valve deterioration, using the valve-in-valve technique. A total of 33 consecutive patients with symptomatic structural bioprosthetic valve deterioration was treated at the authors' institution, using the valve-in-valve technique. The valve-in-valve procedure in the aortic position was performed in 23 patients (mean age 81.4 ± 5.9 years; mean STS score 9.6 ± 5.4). The self-expandable and balloon-expandable devices were used in 21 cases (91.3%) and two cases (8.7%), respectively. Procedures were performed via the trans-femoral, trans-axillary and trans-apical routes in 18 (78.2%), three (13%) and two (8.7%) cases, respectively. After the procedure, all patients were in NYHA class I/II. Survival rates were 95.6% at the one-year follow up. The valve-in-valve procedure in the mitral position was performed in 10 patients (mean age 73.6 ± 15 years; mean STS score 7.7 ± 4.1). All procedures were performed using the balloon-expandable device via the trans-apical route. The composite end point of device success was achieved in all patients. Survival rates were 100% and 75% at one month and two years' follow up, respectively. A single valve-in-valve implantation within a failed tricuspid bioprosthetic valve was also successfully performed. In the authors' experience, the valve-in-valve technique for the treatment of a wide range of bioprosthetic valve deterioration modes of failure in different valve positions is safe and very effective.

  15. The JUPITER registry: 1-year results of transapical aortic valve implantation using a second-generation transcatheter heart valve in patients with aortic stenosis.

    Science.gov (United States)

    Silaschi, Miriam; Treede, Hendrik; Rastan, Ardawan J; Baumbach, Hardy; Beyersdorf, Friedhelm; Kappert, Utz; Eichinger, Walter; Rüter, Florian; de Kroon, Thomas L; Lange, Rüdiger; Ensminger, Stephan; Wendler, Olaf

    2016-11-01

    Transcatheter aortic valve replacement (TAVR) is an established therapy for patients with aortic stenosis (AS) at high surgical risk. The JenaValve™ is a second-generation, self-expanding transcatheter heart valve (THV), implanted through transapical access (TA). During stent deployment, a specific 'clipping-mechanism' engages native aortic valve cusps for fixation. We present 1-year outcomes of the JUPITER registry, a post-market registry of the JenaValve for TA-TAVR. The JUPITER registry is a prospective, multicentre, uncontrolled and observational European study to evaluate the long-term safety and effectiveness of the Conformité Européenne-marked JenaValve THV. A total of 180 patients with AS were enrolled between 2012 and 2014. End-points were adjudicated in accordance with the valve academic research consortium document no. 1 definitions. The mean age was 80.4 ± 5.9 years and the mean logistic European system for cardiac operative risk evaluation I 21.2 ± 14.7%. The procedure was successful in 95.0% (171/180), implantation of a second THV (valve-in-valve) was performed in 2.2% (4/180) and conversion to surgical aortic valve replacement (SAVR) was necessary in 2.8% (5/180). No annular rupture or coronary ostia obstruction occurred. Two patients required SAVR after the day of index procedure (1.1%). All-cause mortality at 30 days was 11.1% (20/180), being cardiovascular in 7.2% (13/180). A major stroke occurred in 1.1% (2/180) at 30 days, no additional major strokes were observed during 1 year. All-cause mortality after 30 days was 13.1% (21/160) and combined efficacy at 1 year was 80.8% (122/151). At 1-year follow-up, no patient presented with more than moderate paravalvular leakage, while 2 patients (3.2%) showed moderate, 12 (19.0%) mild and 49 (82.4%) trace/none paravalvular regurgitation. In a high-risk cohort of patients undergoing TA-TAVR for AS, the use of the JenaValve THV is safe and effective. In patients at higher risk for coronary ostia

  16. Transcatheter Replacement of Failed Bioprosthetic Valves

    DEFF Research Database (Denmark)

    Simonato, Matheus; Webb, John; Kornowski, Ran

    2016-01-01

    valve mechanism of failure (stenosis/mixed baseline failure: odds ratio, 3.12; confidence interval, 1.51-6.45; P=0.002). Conclusions-High implantation inside failed bioprosthetic valves is a strong independent correlate of lower postprocedural gradients in both self-and balloon-expandable transcatheter......Background-Transcatheter valve implantation inside failed bioprosthetic surgical valves (valve-in-valve [ViV]) may offer an advantage over reoperation. Supra-annular transcatheter valve position may be advantageous in achieving better hemodynamics after ViV. Our objective was to define targets...... for implantation that would improve hemodynamics after ViV. Methods and Results-Cases from the Valve-in-Valve International Data (VIVID) registry were analyzed using centralized core laboratory assessment blinded to clinical events. Multivariate analysis was performed to identify independent predictors of elevated...

  17. Development of an effective valve packing program

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.A.

    1996-12-01

    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV`s and AOV`s, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance.

  18. An improved gate valve for critical applications in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kalsi, M.S.; Alvarez, P.D.; Wang, J.K.; Somagyi, D. [Kalsi Engineering, Inc., Sugar Land, TX (United States)] [and others

    1996-12-01

    U.S. Nuclear Regulatory Commission Generic Letters 89-10 for motor-operated valves (MOVs) and 95-07 for all power-operated valves document in detail the problems related to the performance of the safety-related valves in nuclear power plants. The problems relate to lack of reliable operation under design basis conditions including higher than anticipated stem thrust, unpredictable valve behavior, damage to the valve internals under blowdown/high flow conditions, significant degradation of performance when cycled under AP and flow, thermal binding, and pressure locking. This paper describes an improved motor-operated flexible wedge gate valve design, the GE Sentinel Valve, which is the outcome of a comprehensive and systematic development effort undertaken to resolve the issues identified in the NRC Generic Letters 89-10 and 95-07. The new design provides a reliable, long-term, low maintenance cost solution to the nuclear power industry. One of the key features incorporated in the disc permits the disc flexibility to be varied independently of the disc thickness (pressure boundary) dictated by the ASME Section III Pressure Vessel & Piping Code stress criteria. This feature allows the desired flexibility to be incorporated in the disc, thus eliminating thermal binding problems. A matrix of analyses was performed using finite element and computational fluid dynamics approaches to optimize design for stresses, flexibility, leak-tightness, fluid flow, and thermal effects. The design of the entire product line was based upon a consistent set of analyses and design rules which permit scaling to different valve sizes and pressure classes within the product line. The valve meets all of the ASME Section III Code design criteria and the N-Stamp requirements. The performance of the valve was validated by performing extensive separate effects and plant in-situ tests. This paper summarizes the key design features, analyses, and test results.

  19. What Are the Signs and Symptoms of Heart Valve Disease?

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  20. Butterfly valve of all rubber lining type

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Shosaku; Nakatsuma, Sumiya (Kubota Ltd., Osaka (Japan)); Sasaki, Iwao; Aoki, Naoshi

    1982-08-01

    The valves used for the circulating water pipes for condensers in nuclear and thermal power stations have become large with the increase of power output, and their specifications have become strict. The materials for the valves change from cast iron to steel plate construction. To cope with sea water corrosion, rubber lining has been applied to the internal surfaces of valve boxes, and the build-up welding of stainless steel has been made on the edges of valves. However, recently it is desired to develop butterfly valves, of which the whole valve disks are lined with hard rubber. For the purpose of confirming the performance of large bore valves, a 2600 mm bore butterfly valve of all rubber lining type was used, and the opening and closing test of 1100 times was carried out by applying thermal cycle and pressure difference and using artifical sea water. Also the bending test of hard rubber lining was performed with test pieces. Thus, it was confirmed that the butterfly valves of all rubber lining type have the performance exceeding that of the valves with build-up welding. The course of development of the valves of all rubber lining type, the construction and the items of confirmation by tests of these valves, and the tests of the valve and the hard rubber lining described above are reported.

  1. Mitral valve aneurysm associated with aortic valve endocarditis and regurgitation.

    Science.gov (United States)

    Raval, Amish N; Menkis, Alan H; Boughner, Derek R

    2002-01-01

    Mitral valve aneurysms are rare complications occurring most commonly in association with aortic valve infective endocarditis. [Decroly 1989, Chua 1990, Northridge 1991, Karalis 1992, Roguin 1996, Mollod 1997, Vilacosta 1997, Cai 1999, Vilacosta 1999, Teskey 1999, Chan 2000, Goh 2000, Marcos- Alberca 2000] While the mechanism of the development of this lesion is unclear, complications such as perforation can occur and lead to significant mitral regurgitation. [Decroly 1989, Karalis 1992, Teskey 1999, Vilacosta 1999]; The case of a 69-year-old male with Streptococcus Sanguis aortic valve endocarditis and associated anterior mitral leaflet aneurysm is presented. Following surgery, tissue pathology of the excised lesion revealed myxomatous degeneration and no active endocarditis or inflammatory cells. This may add support to the hypothesis that physical stress due to severe aortic insufficiency and structural weakening, without infection of the anterior mitral leaflet, can lead to the development of this lesion.

  2. Valved stent for off-pump mitral valve replacement

    OpenAIRE

    Ma, L.(School of Physics, Shandong University, Shandong, China)

    2004-01-01

    Résumé Objectif : Evaluer un remplacement de valve mitrale hors-pompe avec des stents valvés Méthode: Des homografts préservés dans du glutaraldehyde ont été suturés dans une prothèse tubulaire avant d'être soudés à deux stents Z en nitinol pour créer deux couronnes auto- extensibles. A) Nous avons testé la valve in vitro en utilisant un circuit pulsatile fermé (mock loop) ayant de débuter les expériences sur les porcs. (n=8, 46 .0± 4.3 kg : B). L'oreillette gauche a été exposée p...

  3. Workshop on gate valve pressure locking and thermal binding

    Energy Technology Data Exchange (ETDEWEB)

    Brown, E.J.

    1995-07-01

    The purpose of the Workshop on Gate Valve Pressure Locking and Thermal Binding was to discuss pressure locking and thermal binding issues that could lead to inoperable gate valves in both boiling water and pressurized water reactors. The goal was to foster exchange of information to develop the technical bases to understand the phenomena, identify the components that are susceptible, discuss actual events, discuss the safety significance, and illustrate known corrective actions that can prevent or limit the occurrence of pressure locking or thermal binding. The presentations were structured to cover U.S. Nuclear Regulatory Commission staff evaluation of operating experience and planned regulatory activity; industry discussions of specific events, including foreign experience, and efforts to determine causes and alleviate the affects; and valve vendor experience and recommended corrective action. The discussions indicated that identifying valves susceptible to pressure locking and thermal binding was a complex process involving knowledge of components, systems, and plant operations. The corrective action options are varied and straightforward.

  4. Mechanical heart valve cavitation in patients with bileaflet valves.

    Science.gov (United States)

    Johansen, Peter; Andersen, Tina S; Hasenkam, J Michael; Nygaard, Hans; Paulsen, Peter K

    2014-01-01

    Today, the quality of mechanical heart valves is quite high, and implantation has become a routine clinical procedure with a low operative mortality (mechanism found to be a possible contributor to these adverse effects is cavitation. In vitro, cavitation has been directly demonstrated by visualization and indirectly in vivo by registering of high frequency pressure fluctuations (HFPF). Tilting disc valves are thought of having higher cavitation potential than bileaflet valves due to higher closing velocities. However, the thromboembolic potential seems to be the same. Further studies are therefore needed to investigate the cavitation potential of bileaflet valves in vivo. The post processing of HFPF have shown difficulties when applied on bileaflet vavles due to asynchronous closure of the two leaflets. The aim of this study was therefore to isolate the pressure signature from each leaflet closure and perform cavitation analyses on each component. Six patients were included in the study (St. Jude Medical (n=3) and CarboMedics (n=3); all aortic bileaflet mechanical heart valves). HFPFs were recorded intraoperatively through a hydrophone at the aortic root. The pressure signature relating to the first and second leaflet closure was isolated and cavitation parameters were calculated (RMS after 50 kHz highpass filtering and signal energy). Data were averaged over 30 heart cycles. For all patients both the RMS value and signal energy of the second leaflet closure were higher than for the first leaflet closure. This indicates that the second leaflet closure is most prone to cause cavitation. Therefore, quantifying cavitation based on the HFPF related to the second leaflet closure may suggest that the cavitation potential for bileaflet valves in vivo may be higher than previous studies have suggested.

  5. Minimally Invasive Heart Valve Surgery.

    Science.gov (United States)

    Bouhout, Ismail; Morgant, Marie-Catherine; Bouchard, Denis

    2017-09-01

    Minimally invasive valve surgery represents a recent and significant advance in modern heart surgery. Indeed, many less invasive approaches for both the aortic and mitral valves have been developed in the past 2 decades. These procedures were hypothesized to result in less operative trauma, which might translate into better patient outcomes. However, this clinical benefit remains controversial in the literature. The aim of this review is to discuss the evidence surrounding minimally invasive heart valve surgery in the current era. A systematic search of the literature from 2006-2016 was performed looking for articles reporting early or late outcomes after minimally invasive valve surgery. Less invasive valve surgery is safe and provides long-term surgical outcomes similar to those of standard sternotomy. In addition, these approaches result in a reduction in overall hospital length of stay and may mitigate the risk of early morbidity-mainly postoperative bleeding, transfusions, and ventilation duration. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  6. Structural valve deterioration in the Mitroflow biological heart valve prosthesis

    DEFF Research Database (Denmark)

    Issa, Issa Farah; Poulsen, Steen Hvitfeldt; Waziri, Farhad

    2018-01-01

    OBJECTIVES: Concern has been raised regarding the long-term durability of the Mitroflow biological heart valve prosthesis. Our aim was to assess the incidence of structural valve degeneration (SVD) for the Mitroflow bioprosthesis in a nationwide study in Denmark including all patients alive...... in Denmark who had received a Mitroflow aortic bioprosthesis since 2000. METHODS: Patients alive in Denmark with a Mitroflow bioprosthesis implanted since January 2000 were invited to participate in a nationwide cross-sectional study with a predefined definition of SVD. Of 1552 patients, 861 patients had...

  7. Development of mechanical heart valves - an inspiring tale

    Directory of Open Access Journals (Sweden)

    P Rajashekar

    2015-01-01

    Full Text Available The historical evolution of the prosthetic heart valves from the first attempts with the Hufnagel′s valve in the treatment of the aortic insufficiency to the Starr-Edwards′ ball valve and later the tilting disc valves (Bjork-Shiley etc., and finally the bileaflet valves (St. Jude are discussed. The Indian contribution with Chitra valve is also described.

  8. A retrospective analysis of mitral valve pathology in the setting of bicuspid aortic valves

    Science.gov (United States)

    van Rensburg, Annari; Doubell, Anton

    2017-01-01

    The therapeutic implications of bicuspid aortic valve associations have come under scrutiny in the transcatheter aortic valve implantation era. We evaluate the spectrum of mitral valve disease in patients with bicuspid aortic valves to determine the need for closer echocardiographic scrutiny/follow-up of the mitral valve. A retrospective analysis of echocardiograms done at a referral hospital over five years was conducted in patients with bicuspid aortic valves with special attention to congenital abnormalities of the mitral valve. One hundred and forty patients with a bicuspid aortic valve were included. A congenital mitral valve abnormality was present in eight (5.7%, P = 0.01) with a parachute mitral valve in four (2.8%), an accessory mitral valve leaflet in one (0.7%), mitral valve prolapse in one, a cleft in one and the novel finding of a trileaflet mitral valve in one. Minor abnormalities included an elongated anterior mitral valve leaflet (P abnormal papillary muscles (P = 0.002) and an additional chord or tendon in the left ventricle cavity (P = 0.007). Mitral valve abnormalities occur more commonly in patients with bicuspid aortic valves than matched healthy individuals. The study confirms that abnormalities in these patients extend beyond the aorta. These abnormalities did not have a significant functional effect. PMID:28515127

  9. Transcatheter valve-in-valve implantation due to severe aortic regurgitation in a degenerated aortic homograft

    DEFF Research Database (Denmark)

    Olsen, Lene Kjaer; Engstrøm, Thomas; Søndergaard, Lars

    2009-01-01

    a successful valve-in-valve implantation of a CoreValve aortic valve prosthesis through the right subclavian artery in a case of severe aortic regurgitation within a degenerated aortic homograft. The case exemplifies the possibilities of expanding the indications for TAVI, as well as other vascular access...

  10. A retrospective analysis of mitral valve pathology in the setting of bicuspid aortic valves.

    Science.gov (United States)

    van Rensburg, Annari; Herbst, Philip; Doubell, Anton

    2017-06-01

    The therapeutic implications of bicuspid aortic valve associations have come under scrutiny in the transcatheter aortic valve implantation era. We evaluate the spectrum of mitral valve disease in patients with bicuspid aortic valves to determine the need for closer echocardiographic scrutiny/follow-up of the mitral valve. A retrospective analysis of echocardiograms done at a referral hospital over five years was conducted in patients with bicuspid aortic valves with special attention to congenital abnormalities of the mitral valve. One hundred and forty patients with a bicuspid aortic valve were included. A congenital mitral valve abnormality was present in eight (5.7%, P = 0.01) with a parachute mitral valve in four (2.8%), an accessory mitral valve leaflet in one (0.7%), mitral valve prolapse in one, a cleft in one and the novel finding of a trileaflet mitral valve in one. Minor abnormalities included an elongated anterior mitral valve leaflet (P mitral regurgitation (P Mitral valve abnormalities occur more commonly in patients with bicuspid aortic valves than matched healthy individuals. The study confirms that abnormalities in these patients extend beyond the aorta. These abnormalities did not have a significant functional effect. © 2017 The authors.

  11. Should a Regurgitant Mitral Valve Be Replaced Simultaneously with a Stenotic Aortic Valve?

    OpenAIRE

    Christenson, Jan T.; Jordan, Bernard; Bloch, Antoine; Schmuziger, Martin

    2000-01-01

    Mitral valve regurgitation frequently accompanies aortic valve stenosis. It has been suggested that mitral regurgitation improves after aortic valve replacement alone and that the mitral valve need not be replaced simultaneously. Furthermore, mitral regurgitation associated with coronary artery disease, particularly in patients with poor left ventricular function, shows immediate improvement after coronary artery bypass grafting.

  12. Novel Active Combustion Control Valve

    Science.gov (United States)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  13. Active combustion flow modulation valve

    Science.gov (United States)

    Hensel, John Peter; Black, Nathaniel; Thorton, Jimmy Dean; Vipperman, Jeffrey Stuart; Lambeth, David N; Clark, William W

    2013-09-24

    A flow modulation valve has a slidably translating hollow armature with at least one energizable coil wound around and fixably attached to the hollow armature. The energizable coil or coils are influenced by at least one permanent magnet surrounding the hollow armature and supported by an outer casing. Lorentz forces on the energizable coils which are translated to the hollow armature, increase or decrease the flow area to provide flow throttling action. The extent of hollow armature translation depends on the value of current supplied and the direction of translation depends on the direction of current flow. The compact nature of the flow modulation valve combined with the high forces afforded by the actuator design provide a flow modulation valve which is highly responsive to high-rate input control signals.

  14. Promising results after percutaneous mitral valve repair

    DEFF Research Database (Denmark)

    Ihlemann, Nikolaj; Franzen, Olaf; Jørgensen, Erik

    2011-01-01

    Mitral valve regurgitation (MR) is the secondmost frequent valve disease in Europe. Untreated MR causes considerable morbidity and mortality. In the elderly, as many as half of these patients are denied surgery because of an estimated high surgical risk. Percutaneous mitral valve repair...... with the MitraClip system resembles the Alfieristitch where a clip is used to connect the tip of the mitral valve leaflets....

  15. Infective endocarditis following percutaneous pulmonary valve replacement

    DEFF Research Database (Denmark)

    Cheung, Gary; Vejlstrup, Niels; Ihlemann, Nikolaj

    2013-01-01

    Infective endocarditis (IE) following percutaneous pulmonary valve replacement (PPVR) with the Melody valve is rarely reported. Furthermore, there are challenges in this diagnosis; especially echocardiographic evidence of vegetation within the prosthesis may be difficult.......Infective endocarditis (IE) following percutaneous pulmonary valve replacement (PPVR) with the Melody valve is rarely reported. Furthermore, there are challenges in this diagnosis; especially echocardiographic evidence of vegetation within the prosthesis may be difficult....

  16. Pregnancy-induced remodeling of heart valves.

    Science.gov (United States)

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

    2015-11-01

    Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows. Leaflet structure was characterized by leaflet dimensions, and ECM composition was determined using standard biochemical assays. Histological studies assessed changes in cellular and ECM components. Leaflet mechanical properties were assessed using equibiaxial mechanical testing. Collagen thermal stability and cross-linking were assessed using denaturation and hydrothermal isometric tension tests. Pulmonary and tricuspid leaflet areas increased during pregnancy by 35 and 55%, respectively. Leaflet thickness increased by 20% only in the pulmonary valve and largely in the fibrosa (30% thickening). Collagen crimp length was reduced in both the tricuspid (61%) and pulmonary (42%) valves, with loss of crimped area in the pulmonary valve. Thermomechanics showed decreased collagen thermal stability with surprisingly maintained cross-link maturity. The pulmonary leaflet exhibited the biphasic change in extensibility seen in left side valves, whereas the tricuspid leaflet mechanics remained largely unchanged throughout pregnancy. The tricuspid valve exhibits a remodeling response during pregnancy that is significantly diminished from the other three valves. All valves of the heart remodel in pregnancy in a manner distinct from cardiac pathology, with much similarity valve to valve, but with interesting valve-specific responses in the aortic and tricuspid valves. Copyright © 2015 the American Physiological Society.

  17. Effects of the blockage ratio of a valve disk on loss coefficient in a butterfly valve

    Energy Technology Data Exchange (ETDEWEB)

    Rho, Hyung Joon; Lee, Jee Keun [Chonbuk National Univ., Jeonju (Korea, Republic of); Choi, Hee Joo [Firstec Co., Ltd., Changwon (Korea, Republic of)

    2008-01-15

    The loss coefficient of the butterfly valve which allows partial opening of the valve at closed position and is applicable to the small-sized pipe system with the diameter of 1 inch was measured for the variation of the valve disk blockage ratio. Two different types of the valve disk configuration to adjust the blockage ratio were considered. One was the solid type valve disk of which the diameter was changed into the smaller size rather than the pipe diameter, and the other was the perforate type valve disk on which some holes were perforated. The results from two types of valve disk were compared to identify their characteristics in the loss coefficient distributions. The loss coefficient and the controllable angle of the valve disk were decreased exponentially with the decrease of the blockage ratio. In addition, the perforate valve disk had the effect on the higher loss coefficient rather than the solid type valve disk.

  18. A method for evaluating pressure locking and thermal binding of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, T.

    1996-12-01

    A method is described to evaluate the susceptibility of gate valves to pressure locking and thermal binding. Binding of the valve disc in the closed position due to high pressure water trapped in the bonnet cavity (pressure locking) or differential thermal expansion of the disk in the seat (thermal binding) represents a potential mechanism that can prevent safety-related systems from functioning when called upon. The method described here provides a general equation that can be applied to a given gate valve design and set of operating conditions to determine the susceptibility of the valve to fail due to disc binding. The paper is organized into three parts. The first part discusses the physical mechanisms that cause disc binding. The second part describes the mathematical equations. The third part discusses the conclusions.

  19. Double orifice mitral valve; a coincidental finding

    NARCIS (Netherlands)

    Westendorp, Iris C. D.; de Bruin-Bon, H. A. C. M.; Hrudova, Jana

    2006-01-01

    A double orifice mitral valve (DOMV) represents a rare congenital malformation characterised by two valve orifices with two separate subvalvular apparatus. This case demonstrates the necessity of careful imaging of the mitral valve apparatus, not only in patients with atrioventricular septal

  20. Pregnancy in women with prosthetic heart valves

    NARCIS (Netherlands)

    Pieper, P. G.; Balci, A.; Van Dijk, A. P.

    2008-01-01

    Pregnancy in women with mechanical valve prostheses has a high maternal complication rate including valve thrombosis mid death. Coumarin derivatives are relatively safe for the mother with a lower incidence of valve thrombosis than unfractionated and low-molecular-weight heparin, but carry the risk

  1. Pregnancy in women with prosthetic heart valves.

    NARCIS (Netherlands)

    Pieper, P.G.; Balci, A.; Dijk, A.P.J. van

    2008-01-01

    Pregnancy in women with mechanical valve prostheses has a high maternal complication rate including valve thrombosis and death. Coumarin derivatives are relatively safe for the mother with a lower incidence of valve thrombosis than un-fractionated and low-molecular-weight heparin, but carry the risk

  2. Transcatheter mitral valve implantation via transapical approach

    DEFF Research Database (Denmark)

    Sondergaard, Lars; Brooks, Matthew; Ihlemann, Nikolaj

    2015-01-01

    OBJECTIVES: As many as 50% of patients with severe symptomatic mitral valve regurgitation are denied surgical valve replacement or repair due to high operative risk. We describe an early series of cases of transcatheter implantation with a CardiAQ™ mitral valve via a transapical approach. METHODS...

  3. Valve-sparing aortic root replacement†

    NARCIS (Netherlands)

    Koolbergen, David R.; Manshanden, Johan S. J.; Bouma, Berto J.; Blom, Nico A.; Mulder, Barbara J. M.; de Mol, Bas A. J. M.; Hazekamp, Mark G.

    2015-01-01

    To evaluate our results of valve-sparing aortic root replacement and associated (multiple) valve repair. From September 2003 to September 2013, 97 patients had valve-sparing aortic root replacement procedures. Patient records and preoperative, postoperative and recent echocardiograms were reviewed.

  4. Porcine Tricuspid Valve Anatomy and Human Compatibility

    DEFF Research Database (Denmark)

    Waziri, Farhad; Lyager Nielsen, Sten; Hasenkam, J. Michael

    2016-01-01

    before clinical use. The study aim was to evaluate and compare the tricuspid valve anatomy of porcine and human hearts. METHODS: The anatomy of the tricuspid valve and the surrounding structures that affect the valve during a cardiac cycle were examined in detail in 100 fresh and 19 formalin...

  5. Recent NRC research activities addressing valve and pump issues

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, D.L.

    1996-12-01

    The mission of the U.S. Nuclear Regulatory Commission (NRC) is to ensure the safe design, construction, and operation of commercial nuclear power plants and other facilities in the U.S.A. One of the main roles that the Office of Nuclear Regulatory Research (RES) plays in achieving the NRC mission is to plan, recommend, and implement research programs that address safety and technical issues deemed important by the NRC. The results of the research activities provide the bases for developing NRC positions or decisions on these issues. Also, RES performs confirmatory research for developing the basis to evaluate industry responses and positions on various regulatory requirements. This presentation summarizes some recent RES supported research activities that have addressed safety and technical issues related to valves and pumps. These activities include the efforts on determining valve and motor-operator responses under dynamic loads and pressure locking events, evaluation of monitoring equipment, and methods for detecting and trending aging of check valves and pumps. The role that RES is expected to play in future years to fulfill the NRC mission is also discussed.

  6. Aortic valve insufficiency in the teenager and young adult: the role of prosthetic valve replacement.

    Science.gov (United States)

    Bradley, Scott M

    2013-10-01

    The contents of this article were presented in the session "Aortic insufficiency in the teenager" at the congenital parallel symposium of the 2013 Society of Thoracic Surgeons (STS) annual meeting. The accompanying articles detail the approaches of aortic valve repair and the Ross procedure.(1,2) The current article focuses on prosthetic valve replacement. For many young patients requiring aortic valve surgery, either aortic valve repair or a Ross procedure provides a good option. The advantages include avoidance of anticoagulation and potential for growth. In other patients, a prosthetic valve is an appropriate alternative. This article discusses the current state of knowledge regarding mechanical and bioprosthetic valve prostheses and their specific advantages relative to valve repair or a Ross procedure. In current practice, young patients requiring aortic valve surgery frequently undergo valve replacement with a prosthetic valve. In STS adult cardiac database, among patients ≤30 years of age undergoing aortic valve surgery, 34% had placement of a mechanical valve, 51% had placement of a bioprosthetic valve, 9% had aortic valve repair, and 2% had a Ross procedure. In the STS congenital database, among patients 12 to 30 years of age undergoing aortic valve surgery, 21% had placement of a mechanical valve, 18% had placement of a bioprosthetic valve, 30% had aortic valve repair, and 24% had a Ross procedure. In the future, the balance among these options may be altered by design improvements in prosthetic valves, alternatives to warfarin, the development of new patch materials for valve repair, and techniques to avoid Ross autograft failure.

  7. [The Starr-Edwards heart valve: one of the oldest mechanical heart valves still functioning today].

    Science.gov (United States)

    Schoenaker, Michiel H; van Wetten, Herbert B; Morshuis, Wim J

    2015-01-01

    In the 1960s, the Starr-Edwards valve was the first artificial heart valve to be successfully implanted in humans. This valve has now been in use for decades with outstanding results: patients whose life expectancy had previously been short acquired a good prognosis with this development. Nowadays the Starr-Edwards valve is not used anymore, but patients are being described today in whom these valves are still functioning well after more than 40 years.

  8. Robotic mitral valve surgery: a United States multicenter trial.

    Science.gov (United States)

    Nifong, L Wiley; Chitwood, W R; Pappas, P S; Smith, C R; Argenziano, M; Starnes, V A; Shah, P M

    2005-06-01

    In a prospective phase II Food and Drug Administration trial, robotic mitral valve repairs were performed in 112 patients at 10 centers by using the da Vinci surgical system. The safety of performing valve repairs with computerized telemanipulation was studied. After institutional review board approval, informed consent was obtained. Patients had moderate to severe mitral regurgitation. Operative technique included peripheral cardiopulmonary bypass, a 4- to 5-cm right minithoracotomy, a transthoracic aortic crossclamp, and antegrade cardioplegia. The successful study end point was grade 0 or 1 mitral regurgitation by transthoracic echocardiography at 1 month after surgery. Valve repairs included quadrangular resections, sliding plasties, edge-to-edge approximations, and both chordal transfers and replacements. The average age was 56.4 +/- 0.09 years (mean +/- SEM). There were 77 (68.8%) men and 35 (31.2%) women. Valve pathology was myxomatous degeneration in 105 (91.1%), and 103 (92.0%) had type II leaflet prolapse. Leaflet repair times averaged 36.7 +/- 0.2 minutes, with annuloplasty times of 39.6 +/- 0.1 minutes. Total robot, aortic crossclamp, and cardiopulmonary bypass times were 77.9 +/- 0.3 minutes, 2.1 +/- 0.1 hours, and 2.8 +/- 0.1 hours, respectively. On 1-month transthoracic echocardiography, 9 (8.0%) had grade 2 mitral regurgitation, and 6 (5.4%) of these had reoperations (5 replacements and 1 repair). There were no deaths, strokes, or device-related complications. Multiple surgical teams performed robotic mitral valve repairs safely early in development of this procedure, with a reoperation rate of 5.4%. Advancements in robotic design and adjunctive technologies may help in the evolution of this minimally invasive technique by decreasing operative times.

  9. Role of novel anticoagulants for patients with mechanical heart valves.

    Science.gov (United States)

    Forsberg, Peter; DeSancho, Maria T

    2014-11-01

    The introduction of the target-specific oral anticoagulants (TSOACs) has led to a major shift in the management of patients at risk for thrombosis. The landscape continues to evolve as the evidence regarding their efficacy and safety in various clinical situations emerges. Antithrombotic therapy for thromboprophylaxis in patients with mechanical heart valves is challenging. To date, the RE-ALIGN trial comparing dabigatran etexilate to warfarin is the only randomized controlled study in this patient population. The higher risk of thromboembolic and bleeding events in the group of patients who received dabigatran compared with warfarin reinforced current guidelines recommending against the use of TSOACs in patients with mechanical heart valves. However, additional studies are needed to find suitable alternatives to vitamin K antagonists in this unique patient population.

  10. Imaging of Cardiac Valves by Computed Tomography

    OpenAIRE

    Gudrun Feuchtner

    2013-01-01

    This paper describes “how to” examine cardiac valves with computed tomography, the normal, diseased valves, and prosthetic valves. A review of current scientific literature is provided. Firstly, technical basics, “how to” perform and optimize a multislice CT scan and “how to” interpret valves on CT images are outlined. Then, diagnostic imaging of the entire spectrum of specific valvular disease by CT, including prosthetic heart valves, is highlighted. The last part gives a guide “how to” use ...

  11. Field Experience with Lock Culvert Valves

    Science.gov (United States)

    2013-12-01

    interesting accounts regarding their lock culvert valves. ST. LAWRENCE SEAWAY Eisenhower and Snell Locks. The valves on the Eisenhower and Snell Locks...Tainter Valve Design Lift, ft Eisenhower St. Lawrence Seaway 80 x 860 12 x 14 21.0 DSP 43 Snell St. Lawrence Seaway 80 x 860 12 x 14 21.0 3 DSP, 1 VF 49...vertical-frame valves were furnished to the SLSDC in January 2011, and one was installed in the south filling-valve location at Snell Lock. An option

  12. Isolated tricuspid valve infective endocarditis

    African Journals Online (AJOL)

    1990-07-07

    Jul 7, 1990 ... Case 2. Initial chest radiograph showing rounded shadows with cavitation. Fig. 2. Case 2. Chest radiograph showing progression to effusion. nuc/eacum was Isolated from repeated blood cultures. Two- dimensional echocardiography revealed vegetations on the tricuspid valve (Fig. 3). The patient was now ...

  13. Optothermally actuated capillary burst valve

    DEFF Research Database (Denmark)

    Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders

    2017-01-01

    be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett...

  14. Mitral valve surgery - minimally invasive

    Science.gov (United States)

    ... be able to store blood in the blood bank for transfusions during and after your surgery. Ask ... Mechanical heart valves do not fail often. However, blood clots can develop on them. If a blood clot forms, you may have a stroke. Bleeding can occur, ...

  15. Aortic valve surgery - minimally invasive

    Science.gov (United States)

    ... be able to store blood in the blood bank for transfusions during and after your surgery. Ask ... Mechanical heart valves do not fail often. However, blood clots can develop on them. If a blood clot forms, you may have a stroke. Bleeding can occur, ...

  16. Hemodynamics driven cardiac valve morphogenesis.

    Science.gov (United States)

    Steed, Emily; Boselli, Francesco; Vermot, Julien

    2016-07-01

    Mechanical forces are instrumental to cardiovascular development and physiology. The heart beats approximately 2.6 billion times in a human lifetime and heart valves ensure that these contractions result in an efficient, unidirectional flow of the blood. Composed of endocardial cells (EdCs) and extracellular matrix (ECM), cardiac valves are among the most mechanically challenged structures of the body both during and after their development. Understanding how hemodynamic forces modulate cardiovascular function and morphogenesis is key to unraveling the relationship between normal and pathological cardiovascular development and physiology. Most valve diseases have their origins in embryogenesis, either as signs of abnormal developmental processes or the aberrant re-expression of fetal gene programs normally quiescent in adulthood. Here we review recent discoveries in the mechanobiology of cardiac valve development and introduce the latest technologies being developed in the zebrafish, including live cell imaging and optical technologies, as well as modeling approaches that are currently transforming this field. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. Copyright © 2015. Published by Elsevier B.V.

  17. Sequential transcatheter aortic valve implantation due to valve dislodgement - a Portico valve implanted over a CoreValve bioprosthesis

    DEFF Research Database (Denmark)

    Campante Teles, Rui; Costa, Cátia; Almeida, Manuel

    2017-01-01

    Transcatheter aortic valve implantation (TAVI) has become an important treatment in high surgical risk patients with severe aortic stenosis (AS), whose complications need to be managed promptly. The authors report the case of an 86-year-old woman presenting with severe symptomatic AS, rejected fo...

  18. What Is Heart Valve Surgery?

    Science.gov (United States)

    ... called stenosis). • Don’t close properly and let blood leak where it shouldn’t. This is called incompetence, insufficiency or regurgitation. • Prolapse — mitral valve flaps don’t close properly (more common in women).As pressure builds inside the left ventricle, it pushes the ...

  19. Manufacturable plastic microfluidic valves using thermal actuation.

    Science.gov (United States)

    Pitchaimani, Karthik; Sapp, Brian C; Winter, Adam; Gispanski, Austin; Nishida, Toshikazu; Hugh Fan, Z

    2009-11-07

    A low-cost, manufacturable, thermally actuated, plastic microfluidic valve has been developed. The valve contains an encapsulated, temperature-sensitive fluid, which expands, deflecting a thin elastomeric film into a fluidic channel to control fluid flow. The power input for thermal expansion of each microfluidic valve can be controlled using a printed circuit board (PCB)-based controller, which is suitable for mass production and large-scale integration. A plastic microfluidic device with such valves was fabricated using compression molding and thermal lamination. The operation of the valves was investigated by measuring a change in the microchannel's ionic conduction current mediated by the resistance variation corresponding to the deflection of the microvalve. Valve closing was also confirmed by the disappearance of fluorescence when a fluorescent solution was displaced in the valve region. Valve operation was characterized for heater power ranging from 36 mW to 80 mW. When the valve was actuating, the local channel temperature was 10 to 19 degrees C above the ambient temperature depending on the heater power used. Repetitive valve operations (up to 50 times) have been demonstrated with a flow resulting from a hydrostatic head. Valve operation was tested for a flow rate of 0.33-4.7 microL/min.

  20. Mitral Valve Disease: a Comprehensive Review.

    Science.gov (United States)

    Harb, Serge C; Griffin, Brian P

    2017-08-01

    This review aims to provide a comprehensive assessment of mitral valve disease, both mitral stenosis and mitral regurgitation, starting with an overview of the valve anatomy. The advent of three-dimensional imaging has allowed a better representation of the valve anatomy. Rheumatic disease is still the number one cause of mitral stenosis worldwide and percutaneous balloon mitral valvuloplasty remains the therapy of choice when indicated and in anatomically eligible patients. Mitral regurgitation (MR) is classified as primary (i.e., lesion in the mitral apparatus) or secondary (caused by left ventricular geometrical alterations). While surgery, preferably repair, is still the recommended therapy for severe primary MR, percutaneous approaches to repair and/or replace the mitral valve are being extensively investigated. Mitral valve disease is common. A careful understanding of mitral valve anatomy and the disease processes that affect the valve are crucial for providing optimal patient care.

  1. Mitral Valve Repair: The Chordae Tendineae

    Directory of Open Access Journals (Sweden)

    Carlos-A Mestres

    2015-10-01

    Full Text Available Repair of the mitral valve is the treatment of choice for mitral valve regurgitation when the anatomy is favorable. It is well known that mitral valve repair enjoys better clinical and functional results than any other type of valve substitute. This fact is beyond doubt regardless of the etiology of the valve lesion and is of particular importance in degenerative diseases.This review analyzes the most important advances in the knowledge of the anatomy, pathophysiology, and chordal function of the mitral valve as well as the different alternatives in the surgical repair and clinical results of the most prevalent diseases of the mitral valve. An attempt has been made to organize the acquired information available in a practical way.

  2. Conical Seat Shut-Off Valve

    Science.gov (United States)

    Farner, Bruce

    2013-01-01

    A moveable valve for controlling flow of a pressurized working fluid was designed. This valve consists of a hollow, moveable floating piston pressed against a stationary solid seat, and can use the working fluid to seal the valve. This open/closed, novel valve is able to use metal-to-metal seats, without requiring seat sliding action; therefore there are no associated damaging effects. During use, existing standard high-pressure ball valve seats tend to become damaged during rotation of the ball. Additionally, forces acting on the ball and stem create large amounts of friction. The combination of these effects can lead to system failure. In an attempt to reduce damaging effects and seat failures, soft seats in the ball valve have been eliminated; however, the sliding action of the ball across the highly loaded seat still tends to scratch the seat, causing failure. Also, in order to operate, ball valves require the use of large actuators. Positioning the metal-to-metal seats requires more loading, which tends to increase the size of the required actuator, and can also lead to other failures in other areas such as the stem and bearing mechanisms, thus increasing cost and maintenance. This novel non-sliding seat surface valve allows metal-to-metal seats without the damaging effects that can lead to failure, and enables large seating forces without damaging the valve. Additionally, this valve design, even when used with large, high-pressure applications, does not require large conventional valve actuators and the valve stem itself is eliminated. Actuation is achieved with the use of a small, simple solenoid valve. This design also eliminates the need for many seals used with existing ball valve and globe valve designs, which commonly cause failure, too. This, coupled with the elimination of the valve stem and conventional valve actuator, improves valve reliability and seat life. Other mechanical liftoff seats have been designed; however, they have only resulted in

  3. Mitral implant of the Inovare transcatheter heart valve in failed surgical bioprostheses: a novel alternative for valve-in-valve procedures.

    Science.gov (United States)

    Gaia, Diego Felipe; Braz, Ademir Massarico; Simonato, Matheus; Dvir, Danny; Breda, João Roberto; Ribeiro, Gustavo Calado; Ferreira, Carolina Baeta; Souza, José Augusto Marcondes; Buffolo, Enio; Palma, José Honório

    2017-04-01

    Reoperative procedure for the treatment of a failed mitral bioprosthesis is associated with considerable risk. In some cases, mortality is high and might contraindicate the benefit of the procedure. The minimally invasive valve-in-valve (ViV) transcatheter mitral valve implant offers an alternative less-invasive approach, reducing morbidity and mortality. The objective of this paper was to evaluate the mitral ViV approach using the Braile Inovare prosthesis. The transcatheter balloon-expandable Braile Inovare prosthesis was used in 12 cases. Procedures were performed in a hybrid operating room, under fluoroscopic and echocardiographic control. Through left minithoracotomy, the prostheses were implanted through the cardiac apex. Serial echocardiographic and clinical examinations were performed. Follow-up varied from 1 to 30 months. A total of 12 transapical mitral ViV procedures were performed. Patients had a mean age of 61.6 ± 9.9 years and 92% were women. Mean logistic EuroSCORE was 20.1%. Successful valve implantation was possible in all cases. In one case, a right lateral thoracotomy was performed for the removal of an embolized prosthesis. There was no operative mortality. Thirty-day mortality was 8.3%. Ejection fraction was preserved after the implant (66.7%; 64.8%; P  = 0.3). The mitral gradient showed a significant reduction (11 mmHg; 6 mmHg; P  < 0.001). Residual mitral regurgitation was not present. There was no left ventricular outflow tract obstruction. The mitral ViV implant in a failed bioprosthesis is an effective procedure. This possibility might alter prosthesis selection in the future initial surgical prosthesis selection, favouring bioprostheses. Further large trials should explore its safety.

  4. 42 CFR 84.1150 - Exhalation valve leakage test; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test; minimum requirements. 84.1150 Section 84.1150 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Dust...

  5. 42 CFR 84.1137 - Inhalation and exhalation valves; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Inhalation and exhalation valves; minimum requirements. 84.1137 Section 84.1137 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  6. Endobronchial Valve Therapy in Patients with Homogeneous Emphysema Results from the IMPACT Study

    NARCIS (Netherlands)

    Valipour, Arschang; Slebos, Dirk-Jan; Herth, Felix; Darwiche, Kaid; Wagner, Manfred; Ficker, Joachim H.; Petermann, Christoph; Hubner, Ralf-Harto; Stanzel, Franz; Eberhard, Ralf

    2016-01-01

    Rationale: Endobronchial valves (EBVs) have been successfully used in patients with severe heterogeneous emphysema to improve lung physiology. Limited available data suggest that EBVs are also effective in homogeneous emphysema. Objectives: To evaluate the efficacy and safety of EBVs in patients

  7. TriGuard™ HDH embolic deflection device for cerebral protection during transcatheter aortic valve replacement

    NARCIS (Netherlands)

    Samim, Mariam; van der Worp, Bart; Agostoni, Pierfrancesco; Hendrikse, Jeroen; Budde, Ricardo P. J.; Nijhoff, Freek; Ramjankhan, Faiz; Doevendans, Pieter A.; Stella, Pieter R.

    2017-01-01

    Objectives: This study aims to evaluate the safety and performance of the new embolic deflection device TriGuard™HDH in patients undergoing TAVR. Background: Transcatheter aortic valve replacement (TAVR) is associated with a high incidence of new cerebral ischemic lesions. The use of an embolic

  8. A New Hemostasis Valve for Neuroendovascular Procedures

    Science.gov (United States)

    Namba, K.; Song, J.K.; Niimi, Y.; Heran, N.S.; Berenstein, A.

    2007-01-01

    Summary A hemostasis valve is routinely used in neuroendovascular procedures to decrease the risk of thromboembolism1,2. Recently, a new hemostasis valve that is designed to minimize blood loss has been introduced. We report our initial experience in using this new hemostasis valve. In neuroendovascular procedures, a hemostasis valve is commonly used for continuous irrigation of guide and microcatheters to decrease the risk of thromboembolism1,2,3. A conventional hemostasis valve has a rotating seal at the end, which is turned open or closed each time a wire or microcatheter/guidewire is introduced or extracted. Often this results in significant back bleeding. When a rotating seal is adjusted suboptimally during a wire or microcatheter manipulation, leakage of pressurized saline from the end of a hemostasis valve results in stagnation of blood within a guiding catheter, which becomes a potential source of emboli during a procedure. The Guardian Haemostasis Valve (Zerusa Limited, Galway, Ireland) is a new hemostasis valve that is designed to minimize blood loss during interventional procedures by minimizing the opening time of the valve during wire or microcatheter insertion. A continuous sealing mechanism during wire or microcatheter positioning minimizes blood loss and stagnation of blood within the guide catheter. We report our initial experience with the Guardian hemostasis valve. PMID:20566129

  9. Transcatheter aortic valve-in-valve implantation of a CoreValve in a JenaValve prosthesis: a case report.

    Science.gov (United States)

    Lotfi, Shahram; Becker, Michael; Moza, Ajay; Autschbach, Rüdiger; Marx, Nikolaus; Schröder, Jörg

    2017-09-10

    Transcatheter aortic valve implantation has become an accepted treatment modality for inoperable or high-risk surgical patients with symptomatic severe aortic stenosis. We report the case of a 70-year-old white man who was treated for severe symptomatic aortic regurgitation using transcatheter aortic valve implantation from the apical approach. Because of recurrent cardiac decompensation 4 weeks after implantation he underwent the implantation of a left ventricular assist device system. A year later echocardiography showed a severe transvalvular central insufficiency. Our heart team decided to choose a valve-in-valve approach while reducing the flow rate of left ventricular assist device to minimum and pacing with a frequency of 140 beats/minute. There was an excellent result and our patient is doing well with no relevant insufficiency of the aortic valve at 12-month follow-up. This is the first report about a successful treatment of a stenotic JenaValve using a CoreValve Evolut R; the use of a CoreValve Evolut R prosthesis may be an optimal option for valve-in-valve procedures.

  10. Contemporary outcomes in reoperative mitral valve surgery.

    Science.gov (United States)

    Mehaffey, Hunter J; Hawkins, Robert B; Schubert, Sarah; Fonner, Clifford; Yarboro, Leora T; Quader, Mohammed; Speir, Alan; Rich, Jeff; Kron, Irving L; Ailawadi, Gorav

    2017-10-05

    Data suggest that redo mitral valve surgery is being performed in increasing numbers, possibly with superior results according to single-centre studies. The purpose of this study is to describe outcomes of redo mitral valve surgery and identify risk-adjusted predictors of poor outcomes. All (11 973) open mitral valve cases were evaluated (2002-2016) from a regional Society of Thoracic Surgery (STS) database. Patients were stratified by primary versus redo mitral valve surgery. Mixed effects logistic regression models including hospital as a random effect were used to identify risk factors for patients undergoing redo mitral valve surgery. Of all mitral valve cases, 1096 (9.7%) had a previous mitral operation. Redo patients had higher rates of valve replacement and preoperative comorbidities resulting in more complications, operative mortalities (11.1%vs6.5%, pmitral valve surgery increased 10% per year and the observed-to-expected ratios (O/E) for operative mortality in redo mitral surgery improved from 1.44 early in the study period to 0.72 in the most recent era. Redo mitral valve surgery accounts for approximately 10% of mitral valve operations and is associated with increased risk and resource utilisation. However, as the volume of redo mitral surgery increases, outcomes have dramatically improved and are now better than predicted. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. Traumatic Mitral Valve and Pericardial Injury

    Directory of Open Access Journals (Sweden)

    Nissar Shaikh

    2013-01-01

    Full Text Available Cardiac injury after blunt trauma is common but underreported. Common cardiac trauma after the blunt chest injury (BCI is cardiac contusion; it is very rare to have cardiac valve injury. The mitral valve injury during chest trauma occurs when extreme pressure is applied at early systole during the isovolumic contraction between the closure of the mitral valve and the opening of the aortic valve. Traumatic mitral valve injury can involve valve leaflet, chordae tendineae, or papillary muscles. For the diagnosis of mitral valve injury, a high index of suspicion is required, as in polytrauma patients, other obvious severe injuries will divert the attention of the treating physician. Clinical picture of patients with mitral valve injury may vary from none to cardiogenic shock. The echocardiogram is the main diagnostic modality of mitral valve injuries. Patient’s clinical condition will dictate the timing and type of surgery or medical therapy. We report a case of mitral valve and pericardial injury in a polytrauma patient, successfully treated in our intensive care unit.

  12. Bioprosthetic heart valves of the future.

    Science.gov (United States)

    Manji, Rizwan A; Ekser, Burcin; Menkis, Alan H; Cooper, David K C

    2014-01-01

    Glutaraldehyde-fixed bioprosthetic heart valves (GBHVs), derived from pigs or cows, undergo structural valve deterioration (SVD) over time, with calcification and eventual failure. It is generally accepted that SVD is due to chemical processes between glutaraldehyde and free calcium ions in the blood. Valve companies have made significant progress in decreasing SVD from calcification through various valve chemical treatments. However, there are still groups of patients (e.g., children and young adults) that have accelerated SVD of GBHV. Unfortunately, these patients are not ideal patients for valve replacement with mechanical heart valve prostheses as they are at high long-term risk from complications of the mandatory anticoagulation that is required. Thus, there is no "ideal" heart valve replacement for children and young adults. GBHVs represent a form of xenotransplantation, and there is increasing evidence that SVD seen in these valves is at least in part associated with xenograft rejection. We review the evidence that suggests that xenograft rejection of GBHVs is occurring, and that calcification of the valve may be related to this rejection. Furthermore, we review recent research into the transplantation of live porcine organs in non-human primates that may be applicable to GBHVs and consider the potential use of genetically modified pigs as sources of bioprosthetic heart valves. © 2014 John Wiley & Sons A/S.

  13. Oxygen safety

    Science.gov (United States)

    COPD - oxygen safety; Chronic obstructive pulmonary disease - oxygen safety; Chronic obstructive airways disease - oxygen safety; Emphysema - oxygen safety; Heart failure - oxygen-safety; Palliative care - oxygen safety; Hospice - oxygen safety

  14. Flow Characteristics of Butterfly Valve by PIV and CFD

    Science.gov (United States)

    Kim, S. W.; Kim, J. H.; Choi, Y. D.; Lee, Y. H.

    Butterfly valves are widely used as on-off and control valves for industrial process. The importance of butterfly valves as control valves has been increasing because the pressure loss is smaller than other types of valves and compactness is very desirable for installation. These features are desirable for saving energy and high efficiency of instruments.

  15. Mechanical valves in the pulmonary position : An international retrospective analysis

    NARCIS (Netherlands)

    Pragt, Hanna; van Melle, Joost P.; Javadikasgari, Hoda; Seo, Dong Man; Stulak, John M.; Knez, Igor; Hoerer, Juergen; Munoz-Guijosa, Christian; Dehaki, Mahyar G.; Shin, Hong Ju; Dearani, Joseph A.; Dehaki, Maziar G.; Pieper, Petronella G.; Eulenburg, Christine; Dos, Laura; Ebels, Tjark

    2017-01-01

    Objective: Life expectancy of patients with congenital heart disease has improved over the past decades, increasing the need for a durable pulmonary prosthetic valve. Biological valves in various forms have become the valve of choice for pulmonary valve replacement (PVR), but structural valve

  16. Long-term performance of motor-operated valves

    Energy Technology Data Exchange (ETDEWEB)

    Scarbrough, T.G.

    1996-12-01

    The U.S. Nuclear Regulatory Commission (NRC) requires that motor-operated valves (MOVs) important to safety be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. Despite these requirements, operating experience and research revealed problems with the performance of MOVs in operating nuclear power plants. In response to the concerns about MOV performance, the NRC issued Generic Letter (GL) 89-10, {open_quotes}Safety-Related Motor-Operated Valve Testing and Surveillance,{close_quotes} and its supplements. Most licensees have completed the aspects of their GL 89-10 programs associated with the review of MOV design bases, verification of MOV switch settings initially, testing of MOVs under design-basis conditions where practicable, and improvement of evaluations of MOV failures and necessary corrective action. Licensees are establishing processes to ensure that the long-term aspects of their MOV programs, such as periodic verification of MOV capability and the trending of MOV problems, are maintained. The NRC staff is developing a generic letter to address periodic verification of MOV design-basis capability.

  17. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    Science.gov (United States)

    Tabata, Minoru

    2016-03-01

    Minimally invasive aortic valve replacement (MIAVR) is defined as aortic valve replacement avoiding full sternotomy. Common approaches include a partial sternotomy right thoracotomy, and a parasternal approach. MIAVR has been shown to have advantages over conventional AVR such as shorter length of stay and smaller amount of blood transfusion and better cosmesis. However, it is also known to have disadvantages such as longer cardiopulmonary bypass and aortic cross-clamp times and potential complications related to peripheral cannulation. Appropriate patient selection is very important. Since the procedure is more complex than conventional AVR, more intensive teamwork in the operating room is essential. Additionally, a team approach during postoperative management is critical to maximize the benefits of MIAVR.

  18. Aerococcus viridans Native Valve Endocarditis

    Directory of Open Access Journals (Sweden)

    Wenwan Zhou

    2013-01-01

    Full Text Available Aerococcus viridans is an infrequent human pathogen and few cases of infective endocarditis have been reported. A case involving a 69-year-old man with colon cancer and hemicolectomy 14 years previously, without recurrence, is reported. A diagnosis of native mitral valve endocarditis was established on the basis of clinical presentation, characteristic echocardiographic findings and pathological specimen examination after urgent valve replacement. A viridans endocarditis appears to be particularly virulent, requiring a surgical approach in four of 10 cases reported and death in one of nine. Given the aggressive nature of A viridans endocarditis and the variable time to diagnosis (a few days to seven months, prompt recognition of symptoms and echocardiography, in addition to blood cultures, should be performed when symptoms persist.

  19. Myocardial Protection and Financial Considerations of Custodiol Cardioplegia in Minimally Invasive and Open Valve Surgery.

    Science.gov (United States)

    Hummel, Brian W; Buss, Randall W; DiGiorgi, Paul L; Laviano, Brittany N; Yaeger, Nalani A; Lucas, M Lee; Comas, George M

    Single-dose antegrade crystalloid cardioplegia with Custodiol-HTK (histidine-tryptophan-ketoglutarate) has been used for many years. Its safety and efficacy were established in experimental and clinical studies. It is beneficial in complex valve surgery because it provides a long period of myocardial protection with a single dose. Thus, valve procedures (minimally invasive or open) can be performed with limited interruption. The aim of this study is to compare the use of Custodiol-HTK cardioplegia with traditional blood cardioplegia in patients undergoing minimally invasive and open valve surgery. A single-institution, retrospective case-control review was performed on patients who underwent valve surgery in Lee Memorial Health System at either HealthPark Medical Center or Gulf Coast Medical Center from July 1, 2011, through March 7, 2015. A total of 181 valve cases (aortic or mitral) performed using Custodiol-HTK cardioplegia were compared with 181 cases performed with traditional blood cardioplegia. Each group had an equal distribution of minimally invasive and open valve cases. Right chest thoracotomy or partial sternotomy was performed on minimally invasive valve cases. Demographics, perioperative data, clinical outcomes, and financial data were collected and analyzed. Patient outcomes were superior in the Custodiol-HTK cardioplegia group for blood transfusion, stroke, and hospital readmission within 30 days (P < 0.05). No statistical differences were observed in the other outcomes categories. Hospital charges were reduced on average by $3013 per patient when using Custodiol-HTK cardioplegia. Use of Custodiol-HTK cardioplegia is safe and cost-effective when compared with traditional repetitive blood cardioplegia in patients undergoing minimally invasive and open valve surgery.

  20. Force measuring valve assemblies, systems including such valve assemblies and related methods

    Science.gov (United States)

    DeWall, Kevin George [Pocatello, ID; Garcia, Humberto Enrique [Idaho Falls, ID; McKellar, Michael George [Idaho Falls, ID

    2012-04-17

    Methods of evaluating a fluid condition may include stroking a valve member and measuring a force acting on the valve member during the stroke. Methods of evaluating a fluid condition may include measuring a force acting on a valve member in the presence of fluid flow over a period of time and evaluating at least one of the frequency of changes in the measured force over the period of time and the magnitude of the changes in the measured force over the period of time to identify the presence of an anomaly in a fluid flow and, optionally, its estimated location. Methods of evaluating a valve condition may include directing a fluid flow through a valve while stroking a valve member, measuring a force acting on the valve member during the stroke, and comparing the measured force to a reference force. Valve assemblies and related systems are also disclosed.

  1. 3D Printed Multimaterial Microfluidic Valve.

    Directory of Open Access Journals (Sweden)

    Steven J Keating

    Full Text Available We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics.

  2. 3D Printed Multimaterial Microfluidic Valve.

    Science.gov (United States)

    Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics.

  3. Effect of Ahmed valve implantation on late neovascular glaucoma

    Directory of Open Access Journals (Sweden)

    Ping-An Mao

    2013-09-01

    Full Text Available AIM: To discuss the effect and safety of Ahmed valve implantation in late neovascular glaucoma. METHODS: The Ahmed glaucoma valve were implanted in 41 eyes(41 caseswith late neovascular glaucoma, the follow-up was 12 months on average, intraocular pressure was recorded at 1 day, 1 week, 1 month, 3, 6, 12 months respectively after operation and compared with that before operation, at the same time, the complications and treatment were analyzed.RESULTS: The mean intraocular pressure before operation, 1 day, 1 week, 1 month, 3, 6, 12 months after operation was 59.83±5.53, 19.27±8.19, 19.69±6.86, 20.67±6.73, 21.05±6.93, 21.49±7.42, 22.14±8.08mmHg, the mean intraocular pressure before operation was higher than that after operation and the difference was obvious in statistics. Major complications included hyphema, low intraocular pressure early postoperation, shallow anterior chamber, obstruction of the tube, the plate wrapped or exposed.CONCLUSION: Ahmed valve implantation is an effective method to treatlate neovascular glaucoma.

  4. Two-Year Outcomes in Patients With Severe Aortic Valve Stenosis Randomized to Transcatheter Versus Surgical Aortic Valve Replacement

    DEFF Research Database (Denmark)

    Søndergaard, Lars; Steinbrüchel, Daniel Andreas; Ihlemann, Nikolaj

    2016-01-01

    BACKGROUND: The Nordic Aortic Valve Intervention (NOTION) trial was the first to randomize all-comers with severe native aortic valve stenosis to either transcatheter aortic valve replacement (TAVR) with the CoreValve self-expanding bioprosthesis or surgical aortic valve replacement (SAVR), inclu...... population. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01057173....

  5. Simplified surgical-hybrid Melody® valve implantation for paediatric mitral valve disease

    OpenAIRE

    Hofmann, Michael; Dave, Hitendu; Hübler, Michael; Kretschmar, Oliver

    2017-01-01

    Children suffering from left atrioventricular valve (LAVV) disease not amenable to repair represent a significant challenge. The results of surgical reconstruction are not optimal. Valve replacement as an alternative is associated with poor results. The surgical-hybrid approach with implantation of a stented biological valve (bovine jugular vein graft, Melody® valve) seems to represent a new therapeutic option. Here we demonstrate our case, the consideration and the approach to extreme clinic...

  6. [Balloon valvuloplasty for congenital aortic valve stenosis in children].

    Science.gov (United States)

    Wu, Lin; Qi, Chunhua; He, Lan; Liu, Fang; Lu, Ying; Huang, Guoying

    2014-09-01

    To evaluate the efficacy and safety of percutaneous balloon aortic valvuloplasty (PBAV) for congenital aortic valve stenosis in children. This is a retrospective clinical study including 14 children treated with PBAV for congenital aortic valve stenosis from October 2006 to December 2012 in our institute. During clinical follow-up, aortic residual stenosis and restenosis, left ventricular function and the procedure-related complications, including the approach artery injury, and aortic regurgitation were particularly assessed. A total of 14 patients consisting of 12 boys and 2 girls underwent the procedure, with mean age (17.1 ± 10.5) months (range from 8 days to 6 years) and the mean body weight (8.9 ± 5.5) kg (range from 1.9 kg to 23.0 kg). The indication for PBAV was a Doppler-derived peak instaneous gradient of ≥ 75 mmHg(1 mmHg = 0.133 kPa) or a smaller gradient with signs of severe left ventricular dysfunction or left ventricular strain on the ECG. The mean ratio of balloon-annulus was 0.92 ± 0.09 (range from 0.75 to 1.09). The catheter-measured peak systolic valve gradient was successfully relieved in all the patients, decreasing from (69 ± 26) mmHg to (29 ± 13) mmHg immediately after balloon valvuloplasty (t = 7.628, P = 0.000). The Doppler-derived peak and mean gradient decreased from (95 ± 21) mmHg and (50 ± 7) mmHg to (49 ± 16) mmHg and (24 ± 11) mmHg, respectively (t = 7.630, 10.401; P = 0.000, 0.000) . The mean follow-up period was 1 day to 61 months. At follow-up, 2 patients (2/14, 14%) underwent the second balloon valvuloplasty for the significant restenosis, and both showed successful relief of restenosis, however 1 patient required surgical Ross procedure due to significant recurrent systolic pressure gradient and moderate aortic regurgitation 4 years after the second balloon valvuloplasty. Among the 3 young infants who presented with congestive heart failure before intervention, 1 died 1 day after the procedure, the other 2 patients had

  7. Transapical JenaValve in a patient with mechanical mitral valve prosthesis.

    LENUS (Irish Health Repository)

    O' Sullivan, Katie E

    2014-01-29

    We report the first case of transcatheter aortic valve replacement implantation using JenaValve™ in a patient with mechanical mitral valve prosthesis. We believe that the design features of this valve may be particularly suited for use in this setting. © 2014 Wiley Periodicals, Inc.

  8. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease.

    NARCIS (Netherlands)

    Yap, S.C.; Drenthen, W.; Pieper, P.G.; Moons, P.; Mulder, B.J.M.; Klieverik, L.M.; Vliegen, H.W.; Dijk, A.P.J. van; Meijboom, F.J.; Roos-Hesselink, J.W.

    2007-01-01

    BACKGROUND AND AIM OF THE STUDY: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve

  9. Outcome of pregnancy in women after pulmonary autograft valve replacement for congenital aortic valve disease

    NARCIS (Netherlands)

    Yap, Sing-Chien; Drenthen, Willem; Pieper, Petronella G.; Moons, Philip; Mulder, Barbara J. M.; Klieverik, Loes M.; Vliegen, Hubert W.; van Dijk, Arie P. J.; Meijboom, Folkert J.; Roos-Hesselink, Jolien W.

    Background and aim of the study: The pulmonary autograft has been recommended as the valve of choice for aortic valve replacement (AVR) in young women contemplating pregnancy. However, current information on maternal and perinatal outcome of pregnancy in women with pulmonary autograft valve

  10. Double-reed exhaust valve engine

    Science.gov (United States)

    Bennett, Charles L.

    2015-06-30

    An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a double reed outlet valve for controlling the flow of low-pressure working fluid out of the engine. The double reed provides a stronger force resisting closure of the outlet valve than the force tending to open the outlet valve. The double reed valve enables engine operation at relatively higher torque and lower efficiency at low speed, with lower torque, but higher efficiency at high speed.

  11. Percutaneous approaches to mitral valve disease

    National Research Council Canada - National Science Library

    Fassa, A-A; Himbert, D; Brochet, E; Bouleti, C; Vahanian, A

    2015-01-01

    Percutaneous approaches to mitral valve disease consist in modifications of existing surgical techniques, aiming to replicate the favourable outcomes of surgery, with less procedure-related risk, due...

  12. Hammock mitral valve: A rare case report

    Directory of Open Access Journals (Sweden)

    Veeresh F. Manvi

    2014-01-01

    Full Text Available Congenital mitral stenosis is a relatively rare disorder comprising 0.2% of all congenital heart defects. Hammock mitral valve producing severe mitral stenosis is a rare variant of congenital mitral stenosis. We report a 2-year-old boy who had hammock mitral valve producing severe mitral stenosis with severe pulmonary artery hypertension. He underwent successful surgical repair. Post-surgery, the mitral valve opening was adequate without residual stenosis or regurgitation. Pulmonary artery pressure had normalized. Follow-up data showed he had significant clinical and echocardiography improvement. This is the first reported case of successful surgical repair done for hammock mitral valve from our institute.

  13. Stentless aortic valve replacement: an update

    Directory of Open Access Journals (Sweden)

    Kobayashi J

    2011-06-01

    Full Text Available Junjiro KobayashiDepartment of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, JapanAbstract: Although porcine aortic valves or pericardial tissue mounted on a stent have made implantation techniques easier, these valves sacrifice orifice area and increase stress at the attachment of the stent, which causes primary tissue failure. Optimizing hemodynamics to prevent patient–prosthetic mismatch and improve durability, stentless bioprostheses use was revived in the early 1990s. The purpose of this review is to provide a current overview of stentless valves in the aortic position. Retrospective and prospective randomized controlled studies showed similar operative mortality and morbidity in stented and stentless aortic valve replacement (AVR, though stentless AVR required longer cross-clamp and cardiopulmonary bypass time. Several cohort studies showed improved survival after stentless AVR, probably due to better hemodynamic performance and earlier left ventricular (LV mass regression compared with stented AVR. However, there was a bias of operation age and nonrandomization. A randomized trial supported an improved 8-year survival of patients with the Freestyle or Toronto valves compared with Carpentier–Edwards porcine valves. On the contrary, another randomized study did not show improved clinical outcomes up to 12 years. Freedom from reoperation at 12 years in Toronto stentless porcine valves ranged from 69% to 75%, which is much lower than for Carpentier–Edwards Perimount valves. Cusp tear with consequent aortic regurgitation was the most common cause of structural valve deterioration. Cryolife O'Brien valves also have shorter durability compared with stent valves. Actuarial freedom from reoperation was 44% at 10 years. Early prosthetic valve failure was also reported in patients who underwent root replacement with Shelhigh stentless composite grafts. There was no level I or IIa evidence of more effective orifice

  14. Fracturing a dysfunctional Edwards Perimount bioprosthetic valve to facilitate percutaneous valve-in-valve placement of SAPIEN 3 valve with modified delivery system.

    Science.gov (United States)

    Shahanavaz, Shabana; Rockefeller, Toby; Nicolas, Ramzi; Balzer, David

    2017-10-10

    Pulmonary valve replacement via surgical implantation of a bioprosthetic valve (BPV) is a well-established treatment for patients with dysfunctional RV outflow tracts. BPVs are prone to structural deterioration, and will eventually require replacement. Recently, percutaneous valve-in-valve (VIV) placement of transcatheter valves has established itself as a safe and effective alternative to surgical revision. Unfortunately, VIV therapy is inherently limited by the inner diameter of the BPV, which restricts the number of eligible patients. Other centers have reported on the feasibility of cracking certain BPVs with ultra high-pressure balloons in bench testing. We now report cracking an Edwards Perimount BPV in the pulmonary position to facilitate VIV placement of an Edwards SAPIEN 3. The ability to crack the Perimount valve allowed placement of a larger valve than previously considered and minimized the final valve gradient. In an effort to avoid the morbidity and mortality of surgical pulmonary valve replacement, this new strategy will expand the number of patients eligible for percutaneous VIV therapy. © 2017 Wiley Periodicals, Inc.

  15. On-line valve monitoring at the Ormen Lange gas plant

    Energy Technology Data Exchange (ETDEWEB)

    Greenlees, R.; Hale, S. [Score Atlanta Inc., Kennesaw, Georgia (United States)

    2011-07-01

    The purpose of this presentation is to discuss replacing time and labor intensive nuclear outage activities with on line condition monitoring solutions, primarily the periodic verification of MOV functionality discussed in USNRC Generic Letter 96.05. This regulation requires that MOV age related performance degradations are properly identified and accounted for, causing utilities to have to retest valves periodically for the duration of the plants operating license. AECL designed CANDU reactors have a world class performance and safety record, with typical average annual capacity factors of 90%. The CANDU reactor design has the ability to refuel on line, as a result (a) it can be a challenge scheduling all required valve testing into limited duration outage work windows, (b) at multi unit sites, Unit 0 valves can be difficult to test because they are rarely ever out of service, (c) deuterium-oxide (heavy water) moderator is expensive to manufacture, as a result, effective through valve leakage monitoring is essential. These three factors alone make CANDU sites the most suitable candidates for on line valve monitoring systems. Nuclear industry regulations have been instrumental in the development of 'at the valve' diagnostic systems, but diagnostic testing has not typically been utilized to the same degree in other less regulated industries. However, that trend is changing, and the move toward valve diagnostics and condition monitoring has moved fastest in the offshore oil and gas industry on the Norwegian side of the North Sea. The Ormen Lange plant, located on Nyhamna Island on the west coast of Norway, operated by Shell, is one of the worlds most advanced gas processing plants. A stated maintenance goal for the plant is that 70% of the maintenance budget and spend should be based on the results of on line condition monitoring, utilizing monitoring systems equipped with switch sensing, strain gages, hydraulic and pneumatic pressure transducers and

  16. Aortic Calcification: An Early Sign of Heart Valve Problems?

    Science.gov (United States)

    ... the aortic valve — a condition called aortic valve stenosis. Aortic valve calcification may be an early sign ... have any other heart disease symptoms. Calcification and stenosis generally affects people older than age 65. When ...

  17. 40 CFR 63.175 - Quality improvement program for valves.

    Science.gov (United States)

    2010-07-01

    ... (e.g., ball, gate, check); valve manufacturer; valve design (e.g., external stem or actuating... categories, or classes, of valves as needed to distinguish among operating conditions and services associated...

  18. Superior versus inferior Ahmed glaucoma valve implantation.

    Science.gov (United States)

    Pakravan, Mohammad; Yazdani, Shahin; Shahabi, Camelia; Yaseri, Mehdi

    2009-02-01

    To compare the efficacy and safety of Ahmed glaucoma valve (AGV) (New World Medical Inc., Rancho Cucamonga, CA) implantation in the superior versus inferior quadrants. Prospective parallel cohort study. A total of 106 eyes of 106 patients with refractory glaucoma. Consecutive patients with refractory glaucoma underwent AGV implantation in the superior or inferior quadrants. Main outcome measures included intraocular pressure (IOP) and rate of complications. Other outcome measures included best corrected visual acuity (BCVA), number of glaucoma medications, and success rate (defined as at least 30% IOP reduction and 5AGV implantation in the superior and inferior quadrants, respectively. Baseline characteristics were comparable in the study groups, except for preoperative IOP, which was higher in the superior group (P = 0.01). Patients were followed for a mean period of 10.6+/-8.49 months and 10.58+/-6.75 months in the superior and inferior groups, respectively (P = 0.477). BCVA was comparable between the groups at all postoperative visits (P>0.122). After 1 year, statistically significant but comparable IOP reduction from baseline (PAGV implants have similar intermediate efficacy in terms of IOP reduction, decrease in number of glaucoma medications, and preservation of vision. However, the inferior quadrants entail significantly more complications. It may be prudent to avoid AGV implantation in the inferior quadrants if the superior quadrants have no contraindications to surgery. Proprietary or commercial disclosure may be found after the references.

  19. Absorbable Implant to Treat Nasal Valve Collapse.

    Science.gov (United States)

    San Nicoló, Marion; Stelter, Klaus; Sadick, Haneen; Bas, Murat; Berghaus, Alexander

    2017-04-01

    Objective To evaluate the safety and effectiveness of an absorbable implant for lateral cartilage support in subjects with nasal valve collapse (NVC) with 12 months follow-up. Methods Thirty subjects with Nasal Obstruction Symptom Evaluation (NOSE) score ≥ 55 and isolated NVC were treated; 14 cases were performed in an operating suite under general anesthesia and 16 cases were performed in a clinic-based setting under local anesthesia. The implant, a polylactic acid copolymer, was placed with a delivery tool within the nasal wall to provide lateral cartilage support. Subjects were followed up through 12 months postprocedure. Results Fifty-six implants were placed in 30 subjects. The mean preoperative NOSE score was 76.7 ± 14.8, with a range of 55 to 100. At 12 months, the mean score was 35.2 ± 29.2, reflecting an average within-patient reduction of -40.9 ± 31.2 points. The majority (76%) of the subjects were responders defined as having at least one NOSE class improvement or a NOSE score reduction of at least 20%. There were no adverse changes in cosmetic appearance at 12 months postprocedure. Three implants in three subjects required retrieval within 30 days postprocedure and resulted in no clinical sequelae. Conclusion This study demonstrates safety and effectiveness of an absorbable implant for lateral cartilage support in subjects with NVC at 12 months postprocedure. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  20. Clinical Outcomes and Bioprosthetic Valve Function After Transcatheter Aortic Valve Implantation Under Dual Antiplatelet Therapy vs. Aspirin Alone.

    Science.gov (United States)

    Ichibori, Yasuhiro; Mizote, Isamu; Maeda, Koichi; Onishi, Toshinari; Ohtani, Tomohito; Yamaguchi, Osamu; Torikai, Kei; Kuratani, Toru; Sawa, Yoshiki; Nakatani, Satoshi; Sakata, Yasushi

    2017-02-24

    Dual antiplatelet therapy (DAPT) is commonly used after transcatheter aortic valve implantation (TAVI); however, the supporting evidence is limited. To determine if aspirin alone is a better alternative to DAPT, we compared the outcomes of patients treated with DAPT or aspirin alone after TAVI.Methods and Results:We analyzed a total of 144 consecutive patients (92 females, mean age 83±6 years) who underwent implantation of a balloon-expandable transcatheter valve (SAPIEN or SAPIEN XT, Edwards Lifesciences). Patients were divided into DAPT (n=66) or aspirin-alone treatment groups (n=78). At 1 year after TAVI, the composite endpoint, which consisted of all-cause death, myocardial infarction, stroke, and major or life-threatening bleeding complications, occurred significantly less frequently (Kaplan-Meier analysis) in the aspirin-alone group (15.4%) than in the DAPT group (30.3%; P=0.031). Valve function assessed by echocardiography was similar between the 2 treatment groups with respect to effective orifice area (1.78±0.43 cm2in DAPT vs. 1.91±0.46 cm2in aspirin-alone group; P=0.13) and transvalvular pressure gradient (11.1±3.5 mmHg in DAPT vs. 10.3±4.1 mmHg in aspirin-alone group; P=0.31). Treatment with aspirin alone after TAVI had greater safety benefits and was associated with similar valve function as DAPT. These results suggest that treatment with aspirin alone is an acceptable regimen for TAVI patients.

  1. Resurgery for recurrent heart valve diseases

    Directory of Open Access Journals (Sweden)

    Chong-lei REN

    2017-02-01

    Full Text Available Objective To summarize the experience with resurgery for recurrent valvular heart diseases. Methods From June 2004 to June 2015, 28 patients (15 males and 13 females with ages ranging from 44 to 67 years (55.6±6.5 years with recurrent heart valve disease underwent resurgery. The reasons for resurgery included perivalvular leakage (7 cases, bioprosthetic valve decline (6 cases in mitral valve and 3 in tricuspid valve, mechanical prostheses dysfunction (2cases, infective endocarditis after valve replacement (2 cases, restenosis of repaired native valve (1 case, and severe tricuspid insufficiency after left-side valve surgery (7 cases. Resurgery included mitral valve replacement in 18 patients and tricuspid valve replacement in 10. All the patients underwent third or fourth or even fifth cardiac surgery for valve replacement. Results There were 2 hospital deaths with a mortality of 7.1% (2/28. The main causes of early-stage deaths were low cardiac output syndrome. The main postoperative complications were respiratory failure in 3, low cardiac output syndrome in 2, reexploration for bleeding in 2 and serious infectious shock in 1. All the patients were found with the great improvement in heart function and the re-implanted prostheses worked well during follow-up. Conclusions Although resurgery for recurrent heart valve disease poses a continuing challenge to cardiac surgeon, it could be performed with the satisfactory results. The keys to a successful cardiac resurgery include appropriate operational timing, refined surgical technique and reasonable perioperative managements. DOI: 10.11855/j.issn.0577-7402.2017.01.11

  2. Aortic valve replacement with the freestyle stentless bioprosthesis with respect to spacial orientation of patient coronary ostia.

    Science.gov (United States)

    Kalangos, A; Trigo-Trindade, P; Vala, D; Panos, A; Faidutti, B

    2000-06-01

    This study evaluates our results for safety and efficacy of aortic valve replacement using the Freestyle bioprosthesis (Medtronic, Inc, Minneapolis, Minn) with a new modified subcoronary implantation technique. This technique takes into account the spacial orientation of the stentless bioprosthesis in the aortic root with respect to the patient's coronary ostia rather than the native commissures. Fifty-two consecutive patients with predominant aortic valve stenosis underwent aortic valve replacement with a Freestyle bioprosthesis by means of the described modified subcoronary technique over a 15-month period. Fifty of them were followed up by means of echocardiography at discharge, 6 months, and 1 year. There were 19 men and 31 women, with a mean age of 76 +/- 7 years (range, 58-87 years). Valve size ranged from 21 to 27 mm. Patients with bicuspid aortic valves had a significantly larger angle between both coronary ostia than patients with tricuspid aortic valves (P =.0001). The peak and mean systolic gradients decreased significantly during the first postoperative year for each valve size (P spacial orientation of the patient's coronary ostia, has hemodynamic results similar to those of other series with different subcoronary implantation techniques. This technique is reproducible, safe at the coronary ostial level, and effective in accommodating variability in angles between human coronary ostia, ranging from 130 degrees to 170 degrees. Moreover, the great preoperative discrepancies between aortic anulus and sinotubular junction diameters are corrected immediately after operation.

  3. Maximizing prosthetic valve size with the Top Hat supra-annular aortic valve

    DEFF Research Database (Denmark)

    Aagaard, Jan; Geha, Alexander S.

    2007-01-01

    -annular mechanical prostheses (CarboMedics, Inc., Arvada, CO, USA) at two institutions. Size frequency distribution was compared to published series, and to the manufacturer's US registry. The ventriculoaortic junction (VAJ) size was available in 234 patients, and compared to the size of the Top Hat valve implanted......BACKGROUND AND AIM OF THE STUDY: The CarboMedics Top Hat supra-annular aortic valve allows a one-size (and often two-size) increase over the standard intra-annular valve. This advantage should minimize the risk of patient-prosthesis mismatch, where the effective prosthetic valve orifice area...... is less than that of a normal valve. It is suggested that the ability to implant Top Hat valves having greater size, relative to standard intra-annular valves, may currently be under-utilized. Further, there has been some concern that Top Hat implantation can cause obstruction of the coronary ostia...

  4. Cylinder valve packing nut studies

    Energy Technology Data Exchange (ETDEWEB)

    Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  5. The Heimlich Valve for Pleural Cavity Drainage

    African Journals Online (AJOL)

    The valve drains into a plastic bag that can be held at any level, allowing the patient to be ambulatory by carrying the bag. The construction and function of the valve is easily understood by medical and nursing staff. It is pre sterilized, stored in a sterile package, and readily utilized on emergency vehicles and in the operating.

  6. Numerical Analysis of Large Diameter Butterfly Valve

    Science.gov (United States)

    Youngchul, Park; Xueguan, Song

    In this paper, a butterfly valve with the diameter of 1,800 mm was studied. Three-dimensional numerical technique by using commercial code CFX were conducted to observe the flow patterns and to measure flow coefficient, hydrodynamic torque coefficient and so on, when the large butterfly valve operated with various angles and uniform incoming velocity.

  7. Successful Thrombolysis of Aortic Prosthetic Valve Thrombosis ...

    African Journals Online (AJOL)

    Arun Kumar Agnihotri

    She delivered a normal baby uneventfully in follow up at full term of pregnancy with no complications. Fibrinolytic therapy for mechanical valve thrombosis is a reasonable alternative to surgery in first trimester of pregnancy. KEY WORDS: Prosthetic valve thrombosis; Echocardiography; Streptokinase;. Thrombolysis; Fetus.

  8. Sealing a Loosely Fitting Valve Assembly

    Science.gov (United States)

    Goff, L.; Tellier, G.

    1986-01-01

    Double-ring seal avoids expense of remachining or redesigning valve parts. Mating fittings on valve sealed by pair of rings - one O-ring and backup ring. Backup ring fills relatively large gap between parts. Prevents softer O-ring from being pushed into and through gap.

  9. High Temperature Resistant Exhaust Valve Spindle

    DEFF Research Database (Denmark)

    Bihlet, Uffe Ditlev

    of the engine, new high temperature alloys are required for a specific engine component, the exhaust valve spindle. Two alloys are used for an exhaust valve spindle; one for the bottom of the spindle, and one for the spindle seat. Being placed in the exhaust gas stream, combustion products such as V2O5 and Na2...

  10. Mitral valve disease--morphology and mechanisms.

    Science.gov (United States)

    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.

  11. Mitral valve disease—morphology and mechanisms

    Science.gov (United States)

    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

  12. Anatomical challenges for transcatheter mitral valve intervention

    DEFF Research Database (Denmark)

    De Backer, Ole; Luk, Ngai H V; Søndergaard, Lars

    2016-01-01

    , 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...

  13. Anatomical challenges for transcatheter mitral valve intervention

    DEFF Research Database (Denmark)

    De Backer, Ole; Luk, Ngai H V; Søndergaard, Lars

    2016-01-01

    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...

  14. Device at valves. Anordning vid ventiler

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, M.; Hedlund, P.O.

    1990-07-02

    The invention is intended to be utilized in pipes and at valves where there are risks for accumulation of oxyhydrogen gas. In or at the pipe/valve is located a body of recombining material such as platinum or other platinum metals or its alloys in order to recombine oxyhydrogen gas. (L.F.).

  15. AN ACTIVE VALVE WITH A CLAMPED MEMBRANE

    DEFF Research Database (Denmark)

    2009-01-01

    An active valve for use e.g. in fluidic microsystems is provided, wherein the active valve comprises a membrane having at least one flow gate, arranged between a first and a second substantially rigid element. Adjusting means provides an adjustment of the clamping force on membrane arranged between...

  16. Oil pipeline valve automation for spill reduction

    Energy Technology Data Exchange (ETDEWEB)

    Mohitpour, Mo; Trefanenko, Bill [Enbridge Technology Inc, Calgary (Canada); Tolmasquim, Sueli Tiomno; Kossatz, Helmut [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    Liquid pipeline codes generally stipulate placement of block valves along liquid transmission pipelines such as on each side of major river crossings where environmental hazards could cause or are foreseen to potentially cause serious consequences. Codes, however, do not stipulate any requirement for block valve spacing for low vapour pressure petroleum transportation, nor for remote pipeline valve operations to reduce spills. A review of pipeline codes for valve requirement and spill limitation in high consequence areas is thus presented along with a criteria for an acceptable spill volume that could be caused by pipeline leak/full rupture. A technique for deciding economically and technically effective pipeline block valve automation for remote operation to reduce oil spilled and control of hazards is also provided. In this review, industry practice is highlighted and application of the criteria for maximum permissible oil spill and the technique for deciding valve automation thus developed, as applied to ORSUB pipeline is presented. ORSUB is one of the three initially selected pipelines that have been studied. These pipelines represent about 14% of the total length of petroleum transmission lines operated by PETROBRAS Transporte S.A. (TRANSPETRO) in Brazil. Based on the implementation of valve motorization on these three pipeline, motorization of block valves for remote operation on the remaining pipelines is intended, depending on the success of these implementations, on historical records of failure and appropriate ranking. (author)

  17. Heart Valve Disease among Patients with Hyperprolactinaemia

    DEFF Research Database (Denmark)

    Steffensen, Charlotte; Maegbaek, Merete Lund; Laurberg, Peter

    2012-01-01

    Increased risk of heart valve disease during treatment with certain dopamine agonists, such as cabergoline, has been observed in patients with Parkinson's disease. The same compound is used to treat hyperprolactinemia, but it is unknown whether this also associates with heart valve disease....

  18. Mitral valve repair in acquired dextrocardia.

    Science.gov (United States)

    Elmistekawy, Elsayed; Chan, Vincent; Hynes, Mark; Mesana, Thierry

    2015-10-01

    Surgical correction of valvular heart disease in patients with dextrocardia is extremely rare. We report a surgical case of mitral valve repair in a patient with acquired dextrocardia. Successful mitral valve repair was performed through a right lateral thoracotomy. We describe our surgical strategy and summarize the literature. © The Author(s) 2014.

  19. EXPERIENCE WITH IN ON-X PROSTHESIS IN HEART VALVE REPLACEMENT

    Directory of Open Access Journals (Sweden)

    M. A. Sazonenkov

    2010-01-01

    Full Text Available The prosthesis ON-X carcas has advantages in implantation commodity and safety, effective orifice area. We pe- sent results of this prosthesis usage during perioud of 2006–2009 years. This time 792 operations with AC were completed. In mitral position were implanted 132 (91,7% prostheses ON-X. Of them 80 (60,6% valves were sutured with complete or partial preservation of posterior leaflet and 26 (19,7% valves – with total MV preser- vation. In aortic position we implanted 76 (53,9% valves ON-X. Only 3 cases needed posterior aortoplasty for the N 23 prosthesis implantation. In perioperative and late postoperative periods we didn’t meet prostheses thrombosis or dysfunction. Reoperati- ons for high prosthesis gradients didn’t occur in postoperative period. Late postoperatively there were 3 (1,1% cases of embolic events related to the incorrect anticoagulant treatment. 

  20. Synchronous intra-myocardial ventricular pacing without crossing the tricuspid valve or entering the coronary sinus

    Energy Technology Data Exchange (ETDEWEB)

    Konecny, Tomas; DeSimone, Christopher V.; Friedman, Paul A.; Bruce, Charles [Department of Medicine, Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Asirvatham, Samuel J., E-mail: asirvatham.samuel@mayo.edu [Department of Medicine, Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Department of Pediatric and Adolescent Medicine, Pediatric Cardiology, Mayo Clinic, Rochester, MN (United States)

    2013-05-15

    Ventricular pacing is most commonly performed at the right ventricular (RV) apex. This is not without risk as placement requires crossing the tricuspid valve (TV) and may cause valvular dysfunction and dyssynchronous activation of the ventricles. The fact that the tricuspid valve lies more apically than the mitral valve allows for the possibility of pacing the ventricles from the right atrium (RA) via the “atrio-ventricular septum” without crossing the TV or entering the coronary sinus (CS). In order to mitigate far field activation inherent to current pacing technology, we constructed a novel lead in which the cathode and anode are both intra-myocardial. We demonstrate safety and efficacy of this novel lead for ventricular pacing at the atrio-ventricular septum in canines, including improved synchronous activation of both ventricles, improved differentiation in ventricular versus atrial sensing, while providing reliable ventricular capture, opening novel and a potentially safer alternative to human cardiac resynchronization therapy.

  1. Multidisciplinary optimization of a butterfly valve.

    Science.gov (United States)

    Song, Xue Guan; Wang, Lin; Baek, Seok Heum; Park, Young Chul

    2009-07-01

    A butterfly valve is a type of flow control device, typically used to regulate fluid flow. This paper proposes a new process to meet desired needs in valve design that is characterized by the complex configuration. First, the need is identified according to the valve user/company, and then the problem is defined with a characteristic function. Second, the initial model of valve is made, and then the initial analysis including fluid and/or structural analysis is carried out to predict the fluid and/or structural performance of the valve. Third, the optimization in the form of mathematical functions, which considers single or multiple objective and/or discipline, is handled. This part includes the design of computer experiment, approximation technique, topology optimization and sizing optimization. Finally, the validation experiment is conducted based on the optimum result to verify the accuracy of the optimization. An example is provided to confirm the availability of the process proposed here.

  2. Comments on compressible flow through butterfly valves

    Science.gov (United States)

    Blakenship, John G.

    In the flow analysis of process piping systems, it is desirable to treat control valves in the same way as elbow, reducers, expansions, and other pressure loss elements. In a recently reported research program, the compressible flow characteristics of butterfly valves were investigated. Fisher Controls International, Inc., manufacturer of a wide range of control valves, publishes coefficients that can be used to calculate flow characteristics for the full range of valve movement. The use is described of the manufacturer's data to calculate flow parameters as reported by the researchers who investigated compressible flow through butterfly valves. The manufacturer's data produced consistent results and can be used to predict choked flow and the pressure loss for unchoked flow.

  3. The Leipzig experience with robotic valve surgery.

    Science.gov (United States)

    Autschbach, R; Onnasch, J F; Falk, V; Walther, T; Krüger, M; Schilling, L O; Mohr, F W

    2000-01-01

    The study describes the single-center experience using robot-assisted videoscopic mitral valve surgery and the early results with a remote telemanipulator-assisted approach for mitral valve repair. Out of a series of 230 patients who underwent minimally invasive mitral valve surgery, in 167 patients surgery was performed with the use of robotic assistance. A voice-controlled robotic arm was used for videoscopic guidance in 152 cases. Most recently, a computer-enhanced telemanipulator was used in 15 patients to perform the operation remotely. The mitral valve was repaired in 117 and replaced in all other patients. The voice-controlled robotic arm (AESOP 3000) facilitated videoscopic-assisted mitral valve surgery. The procedure was completed without the need for an additional assistant as "solo surgery." Additional procedures like radiofrequency ablation and tricuspid valve repair were performed in 21 and 4 patients, respectively. Duration of bypass and clamp time was comparable to conventional procedures (107 A 34 and 50 A 16 min, respectively). Hospital mortality was 1.2%. Using the da Vinci telemanipulation system, remote mitral valve repair was successfully performed in 13 of 15 patients. Robotic-assisted less invasive mitral valve surgery has evolved to a reliable technique with reproducible results for primary operations and for reoperations. Robotic assistance has enabled a solo surgery approach. The combination with radiofrequency ablation (Mini Maze) in patients with chronic atrial fibrillation has proven to be beneficial. The use of telemanipulation systems for remote mitral valve surgery is promising, but a number of problems have to be solved before the introduction of a closed chest mitral valve procedure.

  4. Airbag vent valve and system

    Science.gov (United States)

    Peterson, Leslie D. (Inventor); Zimmermann, Richard E. (Inventor)

    2001-01-01

    An energy absorbing airbag system includes one or more vent valve assemblies for controlling the release of airbag inflation gases to maintain inflation gas pressure within an airbag at a substantially constant pressure during a ride-down of an energy absorbing event. Each vent valve assembly includes a cantilever spring that is flat in an unstressed condition and that has a free end portion. The cantilever spring is secured to an exterior surface of the airbag housing and flexed to cause the second free end portion of the cantilever spring to be pressed, with a preset force, against a vent port or a closure covering the vent port to seal the vent port until inflation gas pressure within the airbag reaches a preselected value determined by the preset force whereupon the free end portion of the cantilever spring is lifted from the vent port by the inflation gases within the airbag to vent the inflation gases from within the airbag. The resilience of the cantilever spring maintains a substantially constant pressure within the airbag during a ride-down portion of an energy absorbing event by causing the cantilever spring to vent gases through the vent port whenever the pressure of the inflation gases reaches the preselected value and by causing the cantilever spring to close the vent port whenever the pressure of the inflation gases falls below the preselected value.

  5. Study on decellularized porcine aortic valve/poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) hybrid heart valve in sheep model.

    Science.gov (United States)

    Wu, Song; Liu, Ying-Long; Cui, Bin; Qu, Xiang-Hua; Chen, Guo-Qiang

    2007-09-01

    To overcome shortcomings of current heart valve prostheses, novel hybrid valves were fabricated from decellularized porcine aortic valves coated with poly (3-hydroxybutyrate-co-3-hydroxyhexanoate [PHBHHx]). In the mechanical test in vitro, the biomechanical performance of hybrid valve was investigated. In an in vivo study, hybrid valve conduits were implanted in pulmonary position in sheep without cardiopulmonary bypass. Uncoated grafts were used as control. The valves were explanted and examined histologically and biochemically 16 weeks after surgery. The hybrid valve conduits maintained original shapes, were covered by a confluent layer of cells, and had less calcification than uncoated control. The mechanical test in vitro revealed that PHBHHx coating improved tensile strength. The results in vivo indicated that PHBHHx coating reduced calcification and promoted the repopulation of hybrid valve with the recipient's cells resembling native valve tissue. The hybrid valve may provide superior valve replacement with current techniques.

  6. Status of Functional Qualification System for Nuclear Valve Assembly in KIMM

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. H.; Park, T. J.; Kim, Y. J. [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2016-05-15

    In this paper, the status of the test facility, the basic concept of the ASME QME-1 test, and the future work are presented. The measured performance parameter, such as pressure, temperature, flow rate, thrust, stroke, and time, is used for the maintenance method and the evaluation of the aging and fatigue in the operating valve. In these days, the survival of the safety related valve in severe accident is important issue. In Korea Institute of Machinery and Materials (KIMM), the functional facility and related Quality Assure (QA) system are made. In addition, the qualification research was made for the functional test of the valve as ASME QME-1. The methodology is based on the ASME QME-1 1997. But the future work for the ASME QME-1 2007 was performed. In real situation, the engineering work is needed for the functional test of the nuclear valve in QA system. So the research work for the qualification is needed. The functional qualification of the valve in the nuclear power plant is performed in KIMM The development of the research and facility required in the functional qualification is in progress. Now the functional qualification is possible domestically, that was impossible in previous time due to the lack of qualification technology and facility.

  7. A meta-analysis of robotic vs. conventional mitral valve surgery.

    Science.gov (United States)

    Cao, Christopher; Wolfenden, Hugh; Liou, Kevin; Pathan, Faraz; Gupta, Sunil; Nienaber, Thomas A; Chandrakumar, David; Indraratna, Praveen; Yan, Tristan D

    2015-07-01

    The present study is the first meta-analysis to compare the surgical outcomes of robotic vs. conventional mitral valve surgery in patients with degenerative mitral valve disease. A systematic review of the literature was conducted to identify all relevant studies with comparative data on robotic vs. conventional mitral valve surgery. Predefined primary endpoints included mortality, stroke and reoperation for bleeding. Secondary endpoints included cross-clamp time, cardiopulmonary bypass time, length of hospitalization and duration of intensive care unit (ICU) stay. Echocardiographic outcomes were assessed when possible. Six relevant retrospective studies with comparative data for robotic vs. conventional mitral valve surgery were identified from the existing literature. Meta-analysis demonstrated a superior perioperative survival outcome for patients who underwent robotic surgery. Incidences of stroke and reoperation were not statistically different between the two treatment arms. Patients who underwent robotic surgery required a significantly longer period of cardiopulmonary bypass time and cross-clamp time. However, the lengths of hospitalization and ICU stay were not significantly different. Both surgical techniques appeared to achieve satisfactory echocardiographic outcomes in the majority of patients. Current evidence on comparative outcomes of robotic vs. conventional mitral surgery is limited, and results of the present meta-analysis should be interpreted with caution due to differing patient characteristics. However, it has been demonstrated that robotic mitral valve surgery can be safely performed by expert surgeons for selected patients. A successful robotic program is dependent on a specially trained team and a sufficient volume of referrals to attain and maintain safety.

  8. Smart Electric Valve Controller Based on All Digital Phase-Locked Loop

    Directory of Open Access Journals (Sweden)

    Li Xiaoling

    2014-02-01

    Full Text Available Electric valve has been applied to various occasions and domains. In some adverse environments where such defects of traditional control system as low efficiency and poor safety have been exposed, optical encoder is adopted to detect the motor’s angular speed and displacement and ADPLL is used for generating control logic, so as to regulate switching frequency and duty ratio of pulse wavelength modulation (PWM, alter the motor’s input voltage and current and achieve the open and close control of Electric valve. The system can automatically regulate the rotating speed and the dragging torque of motor based on the open and close position, rotating speed and torque of the valve to make sure that the motor can achieve the best rotating speed and torque. The results of the test by motor 90ZY24-200 prove that the system has prompt response, high accuracy, little harmonic and ripple range; it can also automatically adapt to the torque alteration to realize the protective function of direct current (DC motor. Electric valve control based on ADPLL can not only realize functions of the whole system, but also enjoys a stable and reliable performance. It can reduce the harmonic and ripple, and help the whole system achieve real-time remote control, data collection and transmission, and display the motor torque in LED, so as to control the valve flow stably and accurately through DC motor.

  9. An in vivo model of in situ implantation using pulmonary valved conduit in large animals under off-pump condition.

    Science.gov (United States)

    Wu, Hao; Xu, Zhi-wei; Liu, Xian-min; Gong, Da; Wan, Ju-yi; Xu, Xiu-fang; Zhou, Zi-fan; Li, Wen-bin

    2013-12-01

    The application of pulmonary valved conduit to reconstruct the continuity between right ventricles and pulmonary artery is one of the major surgeries. This study aimed to establish an in vivo model of in situ implantation using pulmonary valved conduit in large animals under off-pump condition to validate the long-term effects of artificial pulmonary valved conduit. Domesticate juvenile male sheep and tissue-engineered porcine pulmonary valved conduit were used for the experiment: 30 sheep, weighing (15 ± 3) kg (range 13 to 17 kg) were randomly divided into two groups which were all operated under general anesthesia by off-pump surgery (group 1) and left thoracotomy (group 2). Two different off-pump surgical methods were used to perform cannulation in sheep pulmonary artery to replace part of sheep pulmonary artery with pulmonary valved conduit which will work together with sheep pulmonary artery and valves. During the experiments, animal survival, complication rates, operating time and blood loss were recorded to compare the results between groups and to establish a surgical method with minimal invasion, simplicity, safety, and high success rates. In group 1, a total of 15 cases of surgeries were performed, in which two sheep died; the operative mortality was 13.3% (2/15). In group 2, a total of 15 cases of surgeries were performed, and the surgical mortality rate was 0 (0/15). The operation time and blood loss in group 2 was significantly better than that in group 1. The postoperative echocardiograms showed that, after the surgeries by these two methods, the blood flows were normal, and the valves can open and close freely. Autopsy after 6 months showed that the inner wall and the valves of pulmonary valved conduit were smooth with no thrombus formation. These two off-pump methods are feasible and safe with fewer traumas; but the second method is better and particularly suitable for the establishment of a juvenile animal model.

  10. 78 FR 54849 - Hazardous Materials: Rail Petitions and Recommendations To Improve the Safety of Railroad Tank...

    Science.gov (United States)

    2013-09-06

    ... of the regulating valves or the safety relief valve, whichever is lower. ] P-1547 Carroll Welding... determine reasonably foreseeable environmental and human health effects? Are there economic benefits or.... Petition P-1547 Summary In petition P-1547, Carroll Welding Supply identifies an area of confusion...

  11. Tritium operating safety seminar, Los Alamos, New Mexico, July 30, 1975

    Energy Technology Data Exchange (ETDEWEB)

    1976-03-01

    A seminar for the exchange of information on tritium operating and safety problems was held at the Los Alamos Scientific Laboratory. The topics discussed are: (1) material use (tubing, lubricants, valves, seals, etc.); (2) hardware selection (valves, fittings, pumps, etc.); (3) biological effects; (4) high pressure; (5) operating procedures (high pressure tritium experiment at LLL); (6) incidents; and (7) emergency planning. (TFD)

  12. Outcome of bioprosthetic valve replacement in dogs with tricuspid valve dysplasia.

    Science.gov (United States)

    Bristow, P; Sargent, J; Luis Fuentes, V; Brockman, D

    2017-04-01

    To describe the short-term and long-term outcome in dogs with tricuspid valve dysplasia undergoing tricuspid valve replacement under cardiopulmonary bypass. Data were collected from the hospital records of all dogs that had undergone tricuspid valve replacement under cardiopulmonary bypass between 2006 and 2012. Dogs were considered candidates for tricuspid valve replacement if they had severe tricuspid valve regurgitation associated with clinical signs of cardiac compromise. Nine dogs of six different breeds were presented. Median age was 13 months (range 7 to 61 months), median weight 26·5 kg (range 9·7 to 59 kg). Eight bovine pericardial valves and one porcine aortic valve were used. One non-fatal intraoperative complication occurred. Complications during hospitalisation occurred in six dogs, four of which were fatal. Of the five dogs discharged, one presented dead due to haemothorax after minor trauma seven days later. The four remaining dogs survived a median of 533 days; all of these dogs received a bovine pericardial valve. Based on our results, tricuspid valve replacement with bovine or porcine prosthetic valves is associated with a high incidence of complications. © 2017 British Small Animal Veterinary Association.

  13. 3D Printed Trileaflet Valve Conduits Using Biological Hydrogels and Human Valve Interstitial Cells

    Science.gov (United States)

    Duan, Bin; Kapetanovic, Edi; Hockaday, Laura A.; Butcher, Jonathan T.

    2014-01-01

    Tissue engineering has great potential to provide a functional de novo living valve replacement capable of integration with host tissue and growth. Among various valve conduit fabrication techniques, 3D bioprinting enables deposition of cells and hydrogels into 3D constructs with anatomical geometry and heterogeneous mechanical properties. Successful translation of this approach is however constrained by the dearth of printable and biocompatible hydrogel materials. Furthermore, it is not known how human valve cells respond to these printed environments. In this study, we develop 3D printable formulations of hybrid hydrogels based on methacrylated hyaluronic acid (Me-HA) and methacrylated gelatin (Me-Gel), and utilize them to bioprint heart valve conduits containing encapsulated human aortic valvular interstitial cells (HAVIC). Increasing Me-Gel concentration resulted in lower stiffness and higher viscosity, facilitated cell spreading, and better maintained HAVIC fibroblastic phenotype. Bioprinting accuracy was dependent upon the relative concentrations of Me-Gel and Me-HA, but when optimized enabled the fabrication of a trileaflet valve shape accurate to the original design. HAVIC encapsulated within bioprinted heart valves maintained high viability, and remodeled the initial matrix by depositing collagen and glyosaminoglycans. These findings represent the first rational design of bioprinted trileaflet valve hydrogels that regulate encapsulated human VIC behavior. The use of anatomically accurate living valve scaffolds through bioprinting may accelerate our understanding of physiological valve cell interactions and our progress towards de novo living valve replacements. PMID:24334142

  14. Quadruple valve replacement with mechanical valves: an 11-year follow-up study.

    Science.gov (United States)

    Cao, Yukun; Gu, Chunhu; Sun, Guocheng; Yu, Shiqiang; Wang, Hongbing; Yi, Dinghua

    2012-06-01

    We performed the first quadruple valve replacement with mechanical valves, combined with the correction of complex congenital heart disease on November 17, 1999. We report here the 11-year follow-up study. A 47-year-old man with subacute rheumatic endocarditis, a ventricular septal defect, and an obstruction of the right ventricular outflow tract required replacement of the aortic, mitral, tricuspid, and pulmonary valves; repair of the ventricular septal defect; and relief of the obstruction of the right ventricular outflow tract. The surgery was done on November 17, 1999, after careful systemic preparation of the patient. Warfarin therapy with a target international normalized ratio (INR) range of 1.5 to 2.0 was used. Follow-up included monitoring the INR, recording the incidences of thromboembolic and bleeding events, electrocardiography, radiography, and echocardiography evaluations. The patient's INR was maintained between 1.5 and 2.0. All 4 mechanical prosthetic heart valves worked well. He is in generally good health without any thromboembolic or bleeding complications. Long-term management is challenging for patients who have experienced quadruple valve replacement with mechanical valves; however, promising results could mean that replacement of all 4 heart valves in 1 operation is feasible in patients with quadruple valve disease, and an INR of 1.5 to 2.0 could be appropriate for Chinese patients with undergoing valve replacement with mechanical valves.

  15. THE RESULTS OF SURGICAL TREATMENT OF TRICUSPID VALVE INFECTIVE ENDOCARDITIS USING VALVE REPAIR AND VALVE REPLACEMENT OPERATIONS

    Directory of Open Access Journals (Sweden)

    S. A. Kovalev

    2015-01-01

    Full Text Available Aim. To evaluate in-hospital and long-term results of surgical treatment of patients with infective endocarditis of the tricuspid valve, to compare the effectiveness of valve repair and valve replacement techniques, and to identify risk factors of mortality and reoperations. Materials and methods. 31 surgical patients with tricuspid valve infective endocarditis were evaluated. Patients were divided into 2 groups. In Group 1 (n = 14 repairs of the tricuspid valve were performed, in Group 2 (n = 17 patients had undergone tricuspid valve replacements. Epidemiological, clinical, microbiological and echocardiographic data were studied. Methods of comparative analysis, the Kaplan–Meier method, and Cox risk models were applied. Results. The most common complication of in-hospital stay was atrioventricular block (17.7% of cases in Group 2. In Group 1, this type of complication was not found. Hospital mortality was 7.14% in Group 1, and 0% in Group 2. Long-term results have shown the significant reduction of heart failure in general cohort and in both groups. In Group 1 the severity of heart failure in the long term was less than in Group 2. No significant differences in the severity of tricuspid regurgitation were found between the groups. In 7-year follow up no cases of death were registered in Group 1. Cumulative survival rate in Group 2 within 60 months was 67.3 ± 16.2%. No reoperations were performed in patients from Group 1. In Group 2, the freedom from reoperation within 60 months was 70.9 ± 15.3%. Combined intervention was found as predictor of postoperative mortality. Prosthetic valve endocarditis was identified as risk factor for reoperation. Conclusion. Valve repair and valve replacement techniques of surgical treatment of tricuspid valve endocarditis can provide satisfactory hospital and long-term results. Tricuspid valve repair techniques allowed reducing the incidence of postoperative atrioventricular block. In the long-term, patients

  16. 49 CFR 192.193 - Valve installation in plastic pipe.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valve installation in plastic pipe. 192.193... Components § 192.193 Valve installation in plastic pipe. Each valve installed in plastic pipe must be designed so as to protect the plastic material against excessive torsional or shearing loads when the valve...

  17. Towards new therapies for calcific aortic valve disease

    NARCIS (Netherlands)

    Riem Vis, P.W.

    2011-01-01

    Calcific aortic valve disease (CAVD) is characterized by progressive calcification of the aortic valve cusps. The end-stage (stenosis), can lead to heart failure and death. Approximately 2-3% of adults over 65 years of age are thought to suffer from valve stenosis, requiring aortic valve

  18. 46 CFR 56.20-9 - Valve construction.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Valve construction. 56.20-9 Section 56.20-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Valves § 56.20-9 Valve construction. (a) Each valve must close with a right-hand (clockwise...

  19. 2-year follow-up of patients undergoing transcatheter aortic valve implantation using a self-expanding valve prosthesis.

    Science.gov (United States)

    Buellesfeld, Lutz; Gerckens, Ulrich; Schuler, Gerhard; Bonan, Raoul; Kovac, Jan; Serruys, Patrick W; Labinaz, Marino; den Heijer, Peter; Mullen, Michael; Tymchak, Wayne; Windecker, Stephan; Mueller, Ralf; Grube, Eberhard

    2011-04-19

    The purpose of this study was to evaluate the safety, device performance, and clinical outcome up to 2 years for patients undergoing transcatheter aortic valve implantation (TAVI). The role of TAVI in the treatment of calcific aortic stenosis evolves rapidly, but mid- and long-term results are scarce. We conducted a prospective, multicenter, single-arm study with symptomatic patients undergoing TAVI for treatment of severe aortic valve stenosis using the 18-F Medtronic CoreValve (Medtronic, Minneapolis, Minnesota) prosthesis. In all, 126 patients (mean age 82 years, 42.9% male, mean logistic European System for Cardiac Operative Risk Evaluation score 23.4%) with severe aortic valve stenosis (mean gradient 46.8 mm Hg) underwent the TAVI procedure. Access was transfemoral in all but 2 cases with subclavian access. Retrospective risk stratification classified 54 patients as moderate surgical risk, 51 patients as high-risk operable, and 21 patients as high-risk inoperable. The overall technical success rate was 83.1%. Thirty-day all-cause mortality was 15.2%, without significant differences in the subgroups. At 2 years, all-cause mortality was 38.1%, with a significant difference between the moderate-risk group and the combined high-risk groups (27.8% vs. 45.8%, p = 0.04). This difference was mainly attributable to an increased risk of noncardiac mortality among patients constituting the high-risk groups. Hemodynamic results remained unchanged during follow-up (mean gradient: 8.5 ± 2.5 mm Hg at 30 days and 9.0 ± 3.4 mm Hg at 2 years). Functional class improved in 80% of patients and remained stable over time. There was no incidence of structural valve deterioration. The TAVI procedure provides sustained clinical and hemodynamic benefits for as long as 2 years for patients with symptomatic severe aortic stenosis at increased risk for surgery. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  20. Motor operated valves problems tests and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pinier, D.; Haas, J.L.

    1996-12-01

    An analysis of the two refusals of operation of the EAS recirculation shutoff valves enabled two distinct problems to be identified on the motorized valves: the calculation methods for the operating torques of valves in use in the power plants are not conservative enough, which results in the misadjustement of the torque limiters installed on their motorizations, the second problem concerns the pressure locking phenomenon: a number of valves may entrap a pressure exceeding the in-line pressure between the disks, which may cause a jamming of the valve. EDF has made the following approach to settle the first problem: determination of the friction coefficients and the efficiency of the valve and its actuator through general and specific tests and models, definition of a new calculation method. In order to solve the second problem, EDF has made the following operations: identification of the valves whose technology enables the pressure to be entrapped: the tests and numerical simulations carried out in the Research and Development Division confirm the possibility of a {open_quotes}boiler{close_quotes} effect: determination of the necessary modifications: development and testing of anti-boiler effect systems.

  1. Standard Practice for Installation, Inspection, and Maintenance of Valve-body Pressure-relief Methods for Geothermal and Other High-Temperature Liquid Applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This practice covers installation, inspection, and maintenance of valve body cavity pressure relief methods for valves used in geothermal and other high-temperature liquid service. The valve type covered by this practice is a design with an isolated body cavity such that when the valve is in either the open or closed position pressure is trapped in the isolated cavity, and there is no provision to relieve the excess pressure internally. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  2. Percutaneous management of prosthetic valve thrombosis.

    Science.gov (United States)

    Hariram, Vuppaladadhiam

    2014-01-01

    Thrombosis of a prosthetic valve is a serious complication in patients with prosthetic heart valves. Thrombolysis is the initial choice of treatment. Patients who do not respond to thrombolysis are subjected to surgery which carries a high risk. We report a case series of 5 patients with prosthetic mitral valve thrombosis who did not respond to thrombolysis and were subjected to percutaneous manipulation of the prosthetic valves successfully and improved. Five patients who were diagnosed to have prosthetic mitral valve thrombosis and failed to respond to a minimum of 36 h of thrombolysis (persistent symptoms with increased gradients, abnormal findings on fluoroscopy),were subjected to percutaneous treatment after receiving proper consent. None of them had a visible thrombus on transthoracic echocardiogram. All patients underwent transseptal puncture following which a 6F JR4 guiding catheter was passed into the left atrium. The valve leaflets were repeatedly hit gently under fluoroscopic guidance till they regained their normal mobility. Mean age was 38.8 years. Average peak and mean gradients prior to the procedure were 38 and 25 and after the procedure were 12 and 6 mm of Hg respectively. All patients had successful recovery of valve motion on fluoroscopy with normalization of gradients and complete resolution of symptoms. None of the patients had any focal neurological deficits, embolic manifestations or bleeding complications. Percutaneous manipulation of prosthetic valves in selected patients with prosthetic valve thrombosis who do not respond to thrombolytic therapy is feasible and can be used as an alternative to surgery. Copyright © 2014 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  3. Transcatheter Aortic Valve Replacement: A Review Article

    Directory of Open Access Journals (Sweden)

    Juan A Siordia

    2016-06-01

    Full Text Available Transcatheter aortic valve replacement (TAVR is a novel therapeutic intervention for the replacement of severely stenotic aortic valves in high-risk patients for standard surgical procedures. Since the initial PARTNER trial results, use of TAVR has been on the rise each year. New delivery methods and different valves have been developed and modified in order to promote the minimally invasive procedure and reduce common complications, such as stroke. This review article focuses on the current data on the indications, risks, benefits, and future directions of TAVR. Recently, TAVR has been considered as a standard-of-care procedure. While this technique is used frequently in high-risk surgical candidates, studies have been focusing on the application of this method for younger patients with lower surgical risk. Moreover, several studies have proposed promising results regarding the use of valve-in-valve technique or the procedure in which the valve is placed within a previously implemented bioprosthetic valve. However, ischemic strokes and paravalvular leak remain a matter of debate in these surgeries. New methods and devices have been developed to reduce the incidence of post-procedural stroke. While the third generation of TAVR valves (i.e., Edwards Sapien 3 and Medtronic Evolut R addresses the issue of paravalvular leak structurally, results on their efficacy in reducing the risk of paravalvular leak are yet to be obtained. Furthermore, TAVR enters the field of hybrid methods in the treatment of cardiac issues via both surgical and catheter-based approaches. Finally, while TAVR is primarily performed on cases with aortic stenosis, new valves and methods have been proposed regarding the application of this technique in aortic regurgitation, as well as other aortic pathologies. TAVR is a suitable therapeutic approach for the treatment of aortic stenosis in high-risk patients. Considering the promising results in the current patient population

  4. Computed Flow Through An Artificial Heart Valve

    Science.gov (United States)

    Rogers, Stewart E.; Kwak, Dochan; Kiris, Cetin; Chang, I-Dee

    1994-01-01

    Report discusses computations of blood flow through prosthetic tilting disk valve. Computational procedure developed in simulation used to design better artificial hearts and valves by reducing or eliminating following adverse flow characteristics: large pressure losses, which prevent hearts from working efficiently; separated and secondary flows, which causes clotting; and high turbulent shear stresses, which damages red blood cells. Report reiterates and expands upon part of NASA technical memorandum "Computed Flow Through an Artificial Heart and Valve" (ARC-12983). Also based partly on research described in "Numerical Simulation of Flow Through an Artificial Heart" (ARC-12478).

  5. Sensitivity study of a valve recession model

    OpenAIRE

    Vera-Cardenas, E.E.; Lewis, R; Slatter, T.

    2017-01-01

    The aim of this work was to carry out a sensitivity\\ud analysis of a valve recession model. \\ud For the sensitivity study, the effects of the param\\ud eters on the valve recession mode\\ud l were \\ud investigated, for both, light duty and heavy duty \\ud engines. It was seen that for light duty \\ud engines, the impact component parameters had the gr\\ud eatest effect on valve recession and \\ud for heavy duty engines the sliding wear component p\\ud arameters have an increasing con-\\ud tribution t...

  6. Rotary Valve FY 2016 Highlights

    Energy Technology Data Exchange (ETDEWEB)

    Fitsos, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-07

    The fiscal year started with the Rotary Valve (RV) being reassembled after having crashed in June of 2015. The crash occurred when the RV inner surface contacted the housing. The cause of the crash was never confirmed. No particles were found in the 2.5 thousandths of an inch gap and the filters the helium gas passed through were all clean. There were marks on the bearings that looked like electrostatic discharge as shown below in Figure 1. These marks hadn’t been seen before and there were similar discharge marks on some of the ball bearings. Examples of this were found in a literature search of bearing failures. This leads to a possible cause due to this arcing affecting the rotational accuracy of the bearings driving the RV into the housing.

  7. Conical seat shut off valve

    Science.gov (United States)

    Farner, Bruce R. (Inventor)

    2012-01-01

    A valve includes a housing defining a bore having an inlet and extending along a longitudinal axis. A head is attached to the housing and defines a head passage having an outlet. A piston is disposed within the bore and includes a piston passage extending through the piston along the longitudinal axis. The piston is moveable between a closed position in which a sealing end of the piston abuts a seat of the head to close fluid communication through the piston passage and an open position in which the sealing end of the piston is axially spaced along the longitudinal axis from the seat of the head to permit fluid communication through the piston passage between the inlet and the outlet. The housing defines an equalizing chamber in fluid communication with the head passage for damping movement of the piston.

  8. Valve Corporation: Composing Internal Markets

    Directory of Open Access Journals (Sweden)

    Todd R. Zenger

    2015-07-01

    Full Text Available Discussions of the Valve Corporation are always enlightening. The skeptic wonders how much is rhetoric and recruiting ploy and how much is real. Is there clear evidence that this organizational design actually works – that it is efficient in this setting? While revenues per employee are quite remarkable, cause and effect are unclear. Is “boss-less-ness” the cause of high sales per employee or simply the result of high sales per employee, fueled from earlier success? The same question could be asked of Google’s unusual organizational approach. Is Google’s success the result of its extensive autonomy granted to employees, or is its past success the enabling cause of such autonomy? Such questions, of course, are empirically unanswerable here. I therefore set them aside and assume this organizational specimen is efficient – well-suited to its environment – and proceed with further commentary.

  9. In vitro balloon dilatation of mitral valve stenosis: the importance of subvalvar involvement as a cause of mitral valve insufficiency

    NARCIS (Netherlands)

    Sadee, A. S.; Becker, A. E.

    1991-01-01

    To investigate the mechanism that increases the orifice area of the mitral valve during balloon dilatation 43 surgically excised intact rheumatic mitral valves were studied. The main pathological features were (a) fibrosis of mitral valve leaflets and commissures (10 valves); (b) fibrosis with

  10. 46 CFR 153.361 - Arrangements for removal of valves from venting systems having multiple relief valves.

    Science.gov (United States)

    2010-10-01

    ... having multiple relief valves. 153.361 Section 153.361 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... removal of valves from venting systems having multiple relief valves. A venting system having multiple... arranged so that cargo vapor will not escape through the opening left after a valve has been removed. ...

  11. Removable butterfly valve, especially for polluting and/or dangerous fluids. Robinet a papillon demontable, notamment pour fluides polluants et/ou dangereux

    Energy Technology Data Exchange (ETDEWEB)

    Garrigues, J.C.

    1984-06-22

    This invention relates to a valve for use in systems carrying polluting, corrosive or dangerous fluids requiring the use of biological protection. The facilities concerned are those in which fluids, mainly polluting, corrosive or dangerous liquids requiring the use of various types of biological protection, are handled. This is particularly so for nuclear installations in which the equipment is surrounded by protective shields which stop the radiation and prevent radioactive gases and aerosols from spreading. The invention proposes for the present valve a high-safety leaktightness system which respects the most specifications and standards and which suppresses any dead volume inside the valve.

  12. Osteoprotegerin inhibits aortic valve calcification and preserves valve function in hypercholesterolemic mice.

    Directory of Open Access Journals (Sweden)

    Robert M Weiss

    Full Text Available There are no rigorously confirmed effective medical therapies for calcific aortic stenosis. Hypercholesterolemic Ldlr (-/- Apob (100/100 mice develop calcific aortic stenosis and valvular cardiomyopathy in old age. Osteoprotegerin (OPG modulates calcification in bone and blood vessels, but its effect on valve calcification and valve function is not known.To determine the impact of pharmacologic treatment with OPG upon aortic valve calcification and valve function in aortic stenosis-prone hypercholesterolemic Ldlr (-/- Apob (100/100 mice.Young Ldlr (-/- Apob (100/100 mice (age 2 months were fed a Western diet and received exogenous OPG or vehicle (N = 12 each 3 times per week, until age 8 months. After echocardiographic evaluation of valve function, the aortic valve was evaluated histologically. Older Ldlr (-/- Apob (100/100 mice were fed a Western diet beginning at age 2 months. OPG or vehicle (N = 12 each was administered from 6 to 12 months of age, followed by echocardiographic evaluation of valve function, followed by histologic evaluation.In Young Ldlr (-/- Apob (100/100 mice, OPG significantly attenuated osteogenic transformation in the aortic valve, but did not affect lipid accumulation. In Older Ldlr (-/- Apob (100/100 mice, OPG attenuated accumulation of the osteoblast-specific matrix protein osteocalcin by ∼80%, and attenuated aortic valve calcification by ∼ 70%. OPG also attenuated impairment of aortic valve function.OPG attenuates pro-calcific processes in the aortic valve, and protects against impairment of aortic valve function in hypercholesterolemic aortic stenosis-prone Ldlr (-/- Apob (100/100 mice.

  13. Computational Fluid Dynamics Analysis of Butterfly Valve Performance Factors

    OpenAIRE

    Del Toro, Adam

    2012-01-01

    Butterfly valves are commonly used in industrial applications to control the internal flow of both compressible and incompressible fluids. A butterfly valve typically consists of a metal disc formed around a central shaft, which acts as its axis of rotation. As the valve's opening angle is increased from 0 degrees (fully closed) to 90 degrees (fully open), fluid is able to more readily flow past the valve. Characterizing a valve's performance factors, such as pressure drop, hydrodynamic torqu...

  14. The 3 S's of the Sapien balloon expandable valve.

    Science.gov (United States)

    Kornowski, Ran

    2016-09-01

    The Sapien 3 (S3) balloon expandable aortic valve equipped with an outer skirt to minimize paravalvular leakage (PVL) was built upon the predecessor Sapien XT (SXT) valve. There is scant comparative data of transcatheter aortic valve replacement using S3 versus SXT valve. The study shows that S3 valve is associated with reduced PVL rate compared with SXT, which is an important clinical advantage. © 2016 Wiley Periodicals, Inc.

  15. Large scale steam valve test: Performance testing of large butterfly valves and full scale high flowrate steam testing

    Energy Technology Data Exchange (ETDEWEB)

    Meadows, J.B.; Robbins, G.E.; Roselius, D.G. [and others

    1995-05-01

    This report presents the results of the design testing of large (36-inch diameter) butterfly valves under high flow conditions. The two butterfly valves were pneumatically operated air-open, air-shut valves (termed valves 1 and 2). These butterfly valves were redesigned to improve their ability to function under high flow conditions. Concern was raised regarding the ability of the butterfly valves to function as required with high flow-induced torque imposed on the valve discs during high steam flow conditions. High flow testing was required to address the flow-induced torque concerns. The valve testing was done using a heavily instrumented piping system. This test program was called the Large Scale Steam Valve Test (LSSVT). The LSSVT program demonstrated that the redesigned valves operated satisfactorily under high flow conditions.

  16. A Hybrid Double Access for Transcatheter Mitral Valve-In-Valve Implantation.

    Science.gov (United States)

    Pagnotta, Paolo; Mennuni, Marco G; Ferrante, Giuseppe; Ornaghi, Diego; Bragato, Renato; Cappai, Antioco; Presbitero, Patrizia

    2015-06-01

    We present a case of hybrid mitral valve-in valve implantation. The planned transapical approach failed due to the inability to cross the degenerated stenotic mitral bioprosthesis. An alternative strategy was performed: first, an anterograde crossing of mitral stenosis, and then, a guidewire externalization through the apex by using a snare. To our knowledge, this is the first described case of double approach mitral valve-in valve implantation. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  17. In vitro evaluation of the iValve: a novel hands-free speech valve.

    Science.gov (United States)

    van der Houwen, Eduard B; van Kalkeren, Tjouwke A; Burgerhof, Johannes G M; van der Laan, Bernard F A M; Verkerke, Gijsbertus J

    2011-12-01

    We performed in vitro evaluation of a novel, disposable, automatic hands-free tracheostoma speech valve for laryngectomy patients based upon the principle of inhalation. The commercially available automatic speech valves close upon strong exhalation and open again when the pressure drops. This method makes long sentences or pauses difficult. The novel iValve is designed to allow almost natural speech, with mid-sentence pausing and whispering. The inhalation closing flows and exhalation opening pressures of 6 iValve prototype versions at different settings were compared with physiological values. The airflow resistance at inhalation was compared to physiological values and to commercial valve values. The iValve prototypes showed flow and pressure ranges in concordance with the physiological values in the literature. The airflow resistance in the breathing mode was within the physiological airflow resistance range, yet above the values from the two commercial valves. The resistance in the speaking mode was above the physiological airflow resistance range. In vitro tests show that the iValve versions can be selected and adjusted to operate within the physiological range. The airflow resistance in the breathing mode is good. In speaking mode, inhalation should, and can, be decreased. The iValve should offer the patient a more intuitively useable alternative with more dynamic speech. Its low cost allows disposability and wider use.

  18. Full metal jacket: transfemoral aortic valve implantation for regurgitant valve after endovascular aortic repair†.

    Science.gov (United States)

    Tanyeli, Omer; Dereli, Yuksel; Gormus, Niyazi; Duzenli, Mehmet Akif

    2017-07-25

    Transfemoral aortic valve implantation has become an almost routine interventional procedure for severe aortic stenosis in high-risk patients. Over time an increased number of experiences has led to unusual procedures. In this report, we present a successful valve-in-valve transfemoral aortic valve implantation in a patient with aortic regurgitation, who previously had debranching and thoracic endovascular aortic repair operations. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  19. Valve selection handbook engineering fundamentals for selecting the right valve design for every industrial flow application

    CERN Document Server

    Smith, Peter

    2004-01-01

    Valves are the components in a fluid flow or pressure system that regulate either the flow or the pressure of the fluid. They are used extensively in the process industries, especially petrochemical. Though there are only four basic types of valves, there is an enormous number of different kinds of valves within each category, each one used for a specific purpose. No other book on the market analyzes the use, construction, and selection of valves in such a comprehensive manner.-Covers new environmentally-conscious equipment and practices, the most important hot-button issue in the p

  20. Cabergoline and cardiac valve disease in prolactinoma patients: additional studies during long-term treatment are required

    NARCIS (Netherlands)

    Kars, M.; Pereira, A. M.; Bax, J. J.; Romijn, J. A.

    2008-01-01

    The increased risk of cardiac valve disease in patients treated for Parkinson's disease with cabergoline has raised concerns about the safety of treatment with ergot-derived dopamine agonists in patients with endocrine diseases, especially prolactinoma. Six cross-sectional studies have been

  1. Low-Mass VOST Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Two low-mass, linear throttling, high-efficiency, leak-proof cryogenic valves of diameters 1/2" and 4" will be built and tested. Based upon cryogenically-proven...

  2. Fluid-solid modeling of lymphatic valves

    Science.gov (United States)

    Caulk, Alexander; Ballard, Matthew; Nepiyushchikh, Zhanna; Dixon, Brandon; Alexeev, Alexander

    2015-11-01

    The lymphatic system performs important physiological functions such as the return of interstitial fluid to the bloodstream to maintain tissue fluid balance, as well as the transport of immune cells in the body. It utilizes contractile lymphatic vessels, which contain valves that open and close to allow flow in only one direction, to directionally pump lymph against a pressure gradient. We develop a fluid-solid model of geometrically representative lymphatic valves. Our model uses a hybrid lattice-Boltzmann lattice spring method to capture fluid-solid interactions with two-way coupling between a viscous fluid and lymphatic valves in a lymphatic vessel. We use this model to investigate the opening and closing of lymphatic valves, and its effect on lymphatic pumping. This helps to broaden our understanding of the fluid dynamics of the lymphatic system.

  3. VOST Flow-Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Two cryogenic flow-control valves of diameters 1/2" and 2" will be built and tested. Based on cryogenically-proven Venturi Off-Set Technology (VOST) they have no...

  4. Modeling study of the ABS relay valve

    Science.gov (United States)

    Lei, Ming; Lin, Min; Guo, Bin; Luo, Zai; Xu, Weidong

    2011-05-01

    The ABS (anti-lock braking system) relay valve is the key component of anti-lock braking system in most commercial vehicles such as trucks, tractor-trailers, etc. In this paper, structure of ABS relay valve and its work theory were analyzed. Then a mathematical model of ABS relay valve, which was investigated by dividing into electronic part, magnetic part, pneumatic part and mechanical part, was set up. The displacement of spools and the response of pressure increasing, holding, releasing of ABS relay valve were simulated and analyzed under conditions of control pressure 500 KPa, braking pressure 600 KPa, atmospheric pressure 100 KPa and air temperature 310 K. Thisarticle provides reliable theory for improving the performance and efficiency of anti-lock braking system of vehicles.

  5. Computed Tomography of Prosthetic Heart Valves

    NARCIS (Netherlands)

    Habets, J.

    2012-01-01

    Prosthetic heart valve (PHV) dysfunction is an infrequent but potentially life-threatening disease with a heterogeneous clinical presentation. Patients with PHV dysfunction clinically can present with symptoms of congestive heart failure (dyspnea, fatigue, edema), fever, angina pectoris, dizziness

  6. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Piezoelectric actuators constructed with the "smart material" PZT offer many potential advantages for use in NASA cryo-valve missions relative to conventional...

  7. VOST Flow-Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A cryogenic flow-control valve based on Venturi-Offset Technology (VOST) will be designed and modeled. VOST provides precise linear flow control within a...

  8. Heart Valve Surgery Recovery and Follow Up

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Heart Valve Surgery Recovery and Follow Up Updated:Sep 14,2016 ... resources from Adam Pick's blog: Traveling Timeline After Heart Surgery 5 Things to Do While Your Heart Mends ( ...

  9. Posterior Urethral Valves with Severe Unilateral Vesicoureteral ...

    African Journals Online (AJOL)

    2004-08-10

    Aug 10, 2004 ... urinary catheter drainage, with no pedal oedema. There ... In patients with posterior urethral valves (PUV), severe unilateral vesicoureteral reflux (VUR) is one ... evaluation of urinary tract infection (UTI), voiding dysfunction, or ...

  10. Automatic balancing valves in distribution networks today

    Energy Technology Data Exchange (ETDEWEB)

    Golestan, F. [Flow Design, Inc., Dallas, TX (United States)

    1996-12-31

    Automatic flow-limiting (self-actuated) valves have been in the heating, ventilating, and air-conditioning (HVAC) market for some time now. Their principle of operation is based on fluid momentum and Bernoulli`s theorem. Basically, they absorb pressure to keep the flow rate constant. The general operation and their flow characteristics are described in the 1992 ASHRAE Handbook--Systems and Equipment, chapter 43 (ASHRAE 1992). The application and interaction of these valves with other system components, when installed in hydronic distribution networks, are outlined in this presentation. A simple, multilevel piping network is analyzed. The network consists of a pump, connecting piping, an automatic temperature control valve (ATC), a coil, and balancing valves.

  11. Novel passive normally closed microfluidic valve

    CSIR Research Space (South Africa)

    Land, K

    2009-09-01

    Full Text Available -8 lithography and replication molding processes. It was successfully implemented, and initial results show the relationship between the applied pressure and flow rate. In addition to being used as a toggle valve, this design also allows...

  12. Minimally Invasive Transcatheter Aortic Valve Replacement (TAVR)

    Medline Plus

    Full Text Available Watch a Broward Health surgeon perform a minimally invasive Transcatheter Aortic Valve Replacement (TAVR) Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2017 BroadcastMed, Inc. All rights reserved.

  13. Low-Mass VOST Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A cylindrical, low-mass, high-efficiency, leak-proof cryogenic valve will be designed using composites and exotic metals. Based upon cryogenically-proven Venturi...

  14. Minimally Invasive Transcatheter Aortic Valve Replacement (TAVR)

    Medline Plus

    Full Text Available Watch a Broward Health surgeon perform a minimally invasive Transcatheter Aortic Valve Replacement (TAVR) Click Here to view the BroadcastMed, Inc. Privacy Policy and Legal Notice © 2017 BroadcastMed, Inc. ...

  15. A Hybrid Tissue-Engineered Heart Valve

    National Research Council Canada - National Science Library

    Alavi, S Hamed; Kheradvar, Arash

    2015-01-01

    This study describes the efforts to develop and test the first hybrid tissue-engineered heart valve whose leaflets are composed of an extra-thin superelastic Nitinol mesh tightly enclosed by uniform...

  16. Glovebox pressure relief and check valve

    Energy Technology Data Exchange (ETDEWEB)

    Blaedel, K.L.

    1986-03-17

    This device is a combined pressure relief valve and check valve providing overpressure protection and preventing back flow into an inert atmosphere enclosure. The pressure relief is embodied by a submerged vent line in a mercury reservior, the releif pressure being a function of the submerged depth. The pressure relief can be vented into an exhaust system and the relieving pressure is only slightly influenced by the varying pressure in the exhaust system. The check valve is embodied by a ball which floats on the mercury column and contacts a seat whenever vacuum exists within the glovebox enclosure. Alternatively, the check valve is embodied by a vertical column of mercury, the maximum back pressure being a function of the height of the column of mercury.

  17. Successful Thrombolysis of Aortic Prosthetic Valve Thrombosis ...

    African Journals Online (AJOL)

    Arun Kumar Agnihotri

    threatening. Standard surgical treatment using cardiopulmonary bypass carries high maternal and fetal complications. Here we report a case of an antenatal female in first trimester with aortic prosthetic valve thrombosis (PVT), who was successfully ...

  18. Frostless heat pump having thermal expansion valves

    Science.gov (United States)

    Chen, Fang C [Knoxville, TN; Mei, Viung C [Oak Ridge, TN

    2002-10-22

    A heat pump system having an operable relationship for transferring heat between an exterior atmosphere and an interior atmosphere via a fluid refrigerant and further having a compressor, an interior heat exchanger, an exterior heat exchanger, a heat pump reversing valve, an accumulator, a thermal expansion valve having a remote sensing bulb disposed in heat transferable contact with the refrigerant piping section between said accumulator and said reversing valve, an outdoor temperature sensor, and a first means for heating said remote sensing bulb in response to said outdoor temperature sensor thereby opening said thermal expansion valve to raise suction pressure in order to mitigate defrosting of said exterior heat exchanger wherein said heat pump continues to operate in a heating mode.

  19. Categorization of motor-operated valves according to the methodology followed by the Joint Owners' Group (JOG); Categorizacion valvulas motorizadas segun la metodologia seguida por el joint owners'group (JOG)

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga Perez, D. de; Arguello Tara, A.; Gallego, J. L.

    2010-07-01

    The Generic Letter 96-05 discuss the periodic verification of the capability of safety-related motor-operated valves to perform their safety functions consistent with the current licensing bases of nuclear power plants, request that addressees implement actions described herein, and require that addressees provide to the NRC a written response to this generic letter relating to implementation of the requested actions. In response, the JOG performed the Joint Owners' group motor operated valves periodic verification program based on tests carried out at 176 valves.

  20. Infective endocarditis following transcatheter aortic valve replacement-

    DEFF Research Database (Denmark)

    Loh, Poay Huan; Bundgaard, Henning; S�ndergaard, Lars

    2013-01-01

    Transcatheter aortic valve replacement (TAVR) can improve the symptoms and prognosis of patients with severe aortic stenosis who, due to a high expected operative risk, would not have otherwise been treated surgically. If these patients develop prosthetic valve endocarditis, their presentations m...... treated medically, discuss the challenges in the diagnosis and management of such patients, and review available literature on the incidence and outcome of the condition. © 2012 Wiley Periodicals, Inc....

  1. Numerical simulation of mitral valve function

    OpenAIRE

    Lau, K. D.

    2012-01-01

    In the mammalian heart there are four heart valves (HV), of which the largest is the mitral valve (MV). Key components in the circulatory system, correct HV function is vital to cardiovascular health. A tethered and asymmetric structure, the MV regulates unidirectional flow between the left atrium and left ventricle. MVfunction is divided between systole/closure, where theMVis required to sustain a pressure load ~120 mmHg whilst minimising flow reversal, and diastole/opening in wh...

  2. Native valve Escherichia coli endocarditis following urosepsis

    Directory of Open Access Journals (Sweden)

    D Rangarajan

    2013-01-01

    Full Text Available Gram-negative organisms are a rare cause of infective endocarditis. Escherichia coli, the most common cause of urinary tract infection and gram-negative septicemia involves endocardium rarely. In this case report, we describe infection of native mitral valve by E. coli following septicemia of urinary tract origin in a diabetic male; subsequently, he required prosthetic tissue valve replacement indicated by persistent sepsis and congestive cardiac failure.

  3. Native valve Escherichia coli endocarditis following urosepsis

    OpenAIRE

    Rangarajan, D.; Ramakrishnan, S.; Patro, K. C.; Devaraj, S.; Krishnamurthy, V.; Kothari, Y.; Satyaki, N.

    2013-01-01

    Gram-negative organisms are a rare cause of infective endocarditis. Escherichia coli, the most common cause of urinary tract infection and gram-negative septicemia involves endocardium rarely. In this case report, we describe infection of native mitral valve by E. coli following septicemia of urinary tract origin in a diabetic male; subsequently, he required prosthetic tissue valve replacement indicated by persistent sepsis and congestive cardiac failure.

  4. Europa Propulsion Valve Seat Material Testing

    Science.gov (United States)

    Addona, Brad M.

    2017-01-01

    The Europa mission and spacecraft design presented unique challenges for selection of valve seat materials that met the fluid compatibility requirements, and combined fluid compatibility and high radiation exposure level requirements. The Europa spacecraft pressurization system valves will be exposed to fully saturated propellant vapor for the duration of the mission. The effects of Nitrogen Tetroxide (NTO) and Monomethylhydrazine (MMH) propellant vapors on heritage valve seat materials, such as Vespel SP-1 and Polychlorotrifluoroethylene (PCTFE), were evaluated to determine if an alternate material is required. In liquid system applications, Teflon is the only available compatible valve seat material. Radiation exposure data for Teflon in an air or vacuum environment has been previously documented. Radiation exposure data for Teflon in an oxidizer environment such as NTO, was not available, and it was unknown whether the effects would be similar to those on air-exposed samples. Material testing was conducted by Marshall Space Flight Center (MSFC) and White Sands Test Facility (WSTF) to determine the effects of propellant vapor on heritage seat materials for pressurization valve applications, and the effects of combined radiation and NTO propellant exposure on Teflon. The results indicated that changes in heritage pressurization valve seat materials' properties rendered them unsuitable for the Europa application. The combined radiation and NTO exposure testing of Teflon produced results equivalent to combined radiation and air exposure results.

  5. A Hybrid Tissue-Engineered Heart Valve.

    Science.gov (United States)

    Alavi, S Hamed; Kheradvar, Arash

    2015-06-01

    This study describes the efforts to develop and test the first hybrid tissue-engineered heart valve whose leaflets are composed of an extra-thin superelastic Nitinol mesh tightly enclosed by uniform tissue layers composed of multiple cell types. The trileaflet Nitinol mesh scaffolds underwent three-dimensional cell culture with smooth muscle and fibroblast/myofibroblast cells enclosing the mesh, which were finally covered by an endothelial cell layer. Quantitative and qualitative assays were performed to analyze the microstructure of the tissues. A tissue composition almost similar to that of natural heart valve leaflets was observed. The function of the valves and their Nitinol scaffolds were tested in a heart flow simulator that confirmed the trileaflet valves open and close robustly under physiologic flow conditions with an effective orifice area of 75%. The tissue-metal attachment of the leaflets once exposed to physiologic flow rates was tested and approved. Our preliminary results indicate that the novel hybrid approach with nondegradable scaffold for engineering heart valves is viable and may address the issues associated with current tissue-engineered valves developed with degradable scaffolds. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Experimental study of asymmetric heart valve prototype

    Science.gov (United States)

    Vukicevic, M.; Fortini, S.; Querzoli, G.; Cenedese, A.; Pedrizzetti, G.

    2011-11-01

    The mechanical heart valves (MHVs) are extremely important medical devices, commonly used for diseased heart valves replacement. Despite the long term of use and constant design refinement, the MHVs are very far from ideal and their performance is very diverse from that of the native ones. It has been approved that small variations in geometry of valvular leaflets influence the significant change in the intraventricular vortical flow, known as one of the most important factors for the overall functionality of the heart. We have experimentally examined the home-made heart valve prototypes, exclusively modeled for the mitral valve replacement. The performance and energetic properties of the prototypes have been compared with those in the presence of standard MHVs. The analysis was based on the testing of intraventricular fluid dynamics, usually missing criteria for the quality of the valve performance. It has been shown that the asymmetric prototype, with unequal leaflets and D-shaped orifice produces flow patterns and energetic properties close to those found in the healthy subjects. Thus, the break of symmetry in the standard bi-leaflet MHV prosthesis, at least from the fluid dynamics point of view, is worthwhile to be considered for the design of MHVs for the mitral valve replacement.

  7. Combined mitral and tricuspid valve repair in rheumatic valve disease: fewer reoperations with prosthetic ring annuloplasty.

    Science.gov (United States)

    Bernal, José M; Pontón, Alejandro; Diaz, Begoña; Llorca, Javier; García, Iván; Sarralde, J Aurelio; Gutiérrez-Morlote, Jesús; Pérez-Negueruela, Carolina; Revuelta, José M

    2010-05-04

    We examined predictors of early and very long-term outcome after combined mitral and tricuspid valve repair for rheumatic disease. Between 1974 and 2002, 153 consecutive patients (mean age, 46.0+/-13.2 years) underwent combined mitral and tricuspid valve repair for rheumatic disease. Mitral disease was predominantly stenosis (82.3%); 100% of patients had organic tricuspid valve disease, predominantly with regurgitation (53.6%) or some degree of tricuspid stenosis (46.4%). Mitral repair included commissurotomy in 132 patients (86.3%) associated with a flexible annuloplasty in 108. Tricuspid valve repair included flexible annuloplasty in 68 patients (44.4%) and suture annuloplasty in 20 patients (13.1%) combined with tricuspid commissurotomy in 62 patients (42.5%). Thirty-day mortality was 5.9%. Late mortality was 60.1%. The median follow-up was 15.8 years (interquartile range, 6 to 19 years). Follow-up was 97.9% complete. Age>65 years was the only predictor of late mortality. Kaplan-Meier survival probability was 74.4% at 10 years and 57.0% at 15 years. Sixty-three patients required valve reoperation (mitral valve, 59; tricuspid valve, 38). Predictors of valve reoperations were either mitral or tricuspid commissurotomy without associated prosthetic ring annuloplasty. At 20 years, Kaplan-Meier freedom from reoperation was 48.5+/-5.1%. Combined mitral and tricuspid valve repair in rheumatic disease showed satisfactory early results. Long-term results were poor because of high mortality and a high number of valve-related reoperations. The use of prosthetic ring annuloplasty was significantly associated with a reduced incidence of both mitral and tricuspid valve reoperations.

  8. Preimplantation Flow Testing of Ahmed Glaucoma Valve and the Early Postoperative Clinical Outcome.

    Science.gov (United States)

    Jones, Emma; Alaghband, Pouya; Cheng, Jason; Beltran-Agullo, Laura; Sheng Lim, Kin

    2013-01-01

    The Ahmed glaucoma valve (AGV) implant is designed to prevent early postoperative hypotony. There is evidence of variation in hypotony rates in clinical trials which may be due to surgical technique variation, entry site leakage or valve defects from 'over priming'. We describe a simple preimplantation gravity driven test to assess valve function after priming that may reduce hypotony rates. Retrospective case note review. An in vivo flow test of AGVs, based on the gravity driven test was introduced prior to implantation. The onset and offset of flow through the valve was measured by altering the height of a bottle of balanced saline solution. We rejected the AGV, if there was fluid still flowing at 10 cm (7 mm Hg) or if there was no flow at 17 cm of water (12 mm Hg). The AGV implantation surgery was without mitomycin C, with a 25G needle entry tract, a corneal or scleral patch graft tube cover and without intracameral viscoelastic. Twenty Ahmed valves were implanted in 16 patients between July 2008 and October 2009. Test failure resulted in four AGV being rejected. The mean preoperative pressure was 29 mm Hg (range, 10-57 mm Hg) and the intraocular pressure (IOP) at 7 days postoperatively was 15 mm Hg (range, 3-52 mm Hg). Hypotony, defined as an IOP of less than 5 mm Hg on two consecutive assessments, was present in two eyes (10%). In vivo flow testing is an important safety check for the AGV. There are also other mechanisms after implantation that can cause an unexpected high or low IOP. How to cite this article: Jones E, Alaghband P, Cheng J, Beltran-Agullo L, Lim KS. Preimplantation Flow Testing of Ahmed Glaucoma Valve and the Early Postoperative Clinical Outcome. J Current Glau Prac 2013;7(1):1-5.

  9. Electromechanically Actuated Valve for Controlling Flow Rate

    Science.gov (United States)

    Patterson, Paul

    2007-01-01

    A proposed valve for controlling the rate of flow of a fluid would include an electric-motor-driven ball-screw mechanism for adjusting the seating element of the valve to any position between fully closed and fully open. The motor would be of a type that can be electronically controlled to rotate to a specified angular position and to rotate at a specified rate, and the ball screw would enable accurate linear positioning of the seating element as a function of angular position of the motor. Hence, the proposed valve would enable fine electronic control of the rate of flow and the rate of change of flow. The uniqueness of this valve lies in a high degree of integration of the actuation mechanism with the flow-control components into a single, relatively compact unit. A notable feature of this integration is that in addition to being a major part of the actuation mechanism, the ball screw would also be a flow-control component: the ball screw would be hollow so as to contain part of the main flow passage, and one end of the ball screw would be the main seating valve element. The relationships among the components of the valve are best understood by reference to the figure, which presents meridional cross sections of the valve in the fully closed and fully open positions. The motor would be supported by a bracket bolted to the valve body. By means of gears or pulleys and a timing belt, motor drive would be transmitted to a sleeve that would rotate on bearings in the valve body. A ball nut inside the sleeve would be made to rotate with the sleeve by use of a key. The ball screw would pass through and engage the ball nut. A key would prevent rotation of the ball screw in the valve body while allowing the ball screw to translate axially when driven by the ball nut. The outer surface of the ball screw would be threaded only in a mid-length region: the end regions of the outer surface of the ball screw would be polished so that they could act as dynamic sealing surfaces

  10. Matched Comparison of Self-Expanding Transcatheter Heart Valves for the Treatment of Failed Aortic Surgical Bioprosthesis: Insights From the Valve-in-Valve International Data Registry (VIVID).

    Science.gov (United States)

    Alnasser, Sami; Cheema, Asim N; Simonato, Matheus; Barbanti, Marco; Edwards, Jeremy; Kornowski, Ran; Horlick, Eric; Wijeysundera, Harindra C; Testa, Luca; Bedogni, Francesco; Amrane, Hafid; Walther, Thomas; Pelletier, Marc; Latib, Azeem; Laborde, Jean-Claude; Hildick-Smith, David; Kim, Won-Keun; Tchetche, Didier; Agrifoglio, Marco; Sinning, Jan-Malte; van Boven, Ad J; Kefer, Joëlle; Frerker, Christian; van Mieghem, Nicolas M; Linke, Axel; Worthley, Stephen; Asgar, Anita; Sgroi, Carmelo; Aziz, Mina; Danenberg, Haim D; Labinaz, Marino; Manoharan, Ganesh; Cheung, Anson; Webb, John G; Dvir, Danny

    2017-04-01

    Transcatheter valve-in-valve implantation is an established therapy for high-risk patients with failed surgical aortic bioprosthesis. There are limited data comparing outcomes of valve-in-valve implantation using different transcatheter heart valves (THV). Patients included in the Valve-in-Valve International Data registry (VIVID) and treated with self-expanding THV devices were analyzed using centralized core laboratory blinded to clinical events. St. Jude Medical Portico versus Medtronic CoreValve were compared in a 1:2 fashion after propensity score matching. A total of 162 patients, Portico- (n=54) and CoreValve- (n=108) based valve-in-valve procedures comprised the study population with no significant difference in baseline characteristics (age, 79±8.2 years; 60% women; mean STS [Society of Thoracic Surgery] score 8.1±5.5%). Postimplantation, CoreValve was associated with a larger effective orifice area (1.67 versus 1.31 cm2; P=0.001), lower mean gradient (14±7.5 versus 17±7.5 mm Hg; P=0.02), and lower core laboratory-adjudicated moderate-to-severe aortic insufficiency (4.2% versus 13.7%; P=0.04), compared with Portico. Procedural complications including THV malpositioning, second THV requirement, or coronary obstruction were not significantly different between the 2 groups. Survival and stroke rates at 30 days were similar, but overall mortality at 1 year was higher among patients treated with Portico compared with CoreValve (22.6% versus 9.1%; P=0.03). In this first matched comparison of THVs for valve-in-valve implantations, Portico and CoreValve demonstrated differences in postprocedural hemodynamics and long-term clinical outcomes. Although this could be related to THV design characteristics, the impact of other procedural factors cannot be excluded and require further evaluation. © 2017 American Heart Association, Inc.

  11. Transcatheter aortic valve implantation with the self-expandable venus A-Valve and CoreValve devices: Preliminary Experiences in China.

    Science.gov (United States)

    Liao, Yan-Biao; Zhao, Zhen-Gang; Wei, Xin; Xu, Yuan-Ning; Zuo, Zhi-Liang; Li, Yi-Jian; Zheng, Ming-Xia; Feng, Yuan; Chen, Mao

    2017-03-01

    Transcatheter aortic valve implantation (TAVI) has been demonstrated to be an effective alternative to surgical aortic valve replacement (SAVR) in patients with aortic stenosis who are deemed high risk or inoperable. Currently, TAVI procedures in China mostly make use of the domestic Venus A-Valve and the CoreValve; however, there is no data on their comparative performance. Consecutive patients undergoing TAVI with the aforementioned devices were included. The outcomes were reported according to the Valve Academic Research Consortium-2 (VARC) definitions. A total of 54 TAVI procedures were performed, 27 with the CoreValve and the other 27 with the Venus A-Valve. An additional valve was required in 4 (14.8%) and 3 (11.1%) patients, and the VARC-2 device success rates were 81.5 and 85.2%, respectively. The incidences of common complications were similar, except for the significantly less frequent pacemaker insertion in the Venus A-Valve group (7.4 vs. 37.0%, P = 0.03). Within 30 days, 2 (3.7%) patients died, 1 in each group, and both had a bicuspid aortic valve (BAV). No other serious complications, such as annular rupture, coronary obstruction and aortic dissection, occurred in the 32 BAV patients treated with the Venus A-Valve (14) or the CoreValve (18). After 2-years of follow-up, there was no significant difference between CoreValve group and Venus-A group (11.1 vs. 7.4%, P = 0.64). TAVI with the domestic Venus A-Valve is feasible, safe, and can produce favorable short-term outcomes comparable to those with the CoreValve in inoperable or high-risk patients with tricuspid and bicuspid aortic valve stenosis. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Shape Memory Actuated Normally Open Permanent Isolation Valve

    Science.gov (United States)

    Ramspacher, Daniel J. (Inventor); Bacha, Caitlin E. (Inventor)

    2017-01-01

    A valve assembly for an in-space propulsion system includes an inlet tube, an outlet tube, a valve body coupling the inlet tube to the outlet tube and defining a propellant flow path, a valve stem assembly disposed within the valve body, an actuator body coupled to the valve body, the valve stem assembly extending from an interior of the valve body to an interior of the actuator body, and an actuator assembly disposed within the actuator body and coupled to the valve stem assembly, the actuator assembly including a shape memory actuator member that when heated to a transition temperature is configured to enable the valve stem assembly to engage the outlet tube and seal the propellant flow path.

  13. Valve-in-valve outcome: design impact of a pre-existing bioprosthesis on the hydrodynamics of an Edwards Sapien XT valve.

    Science.gov (United States)

    Doose, Christian; Kütting, Maximilian; Egron, Sandrine; Farhadi Ghalati, Pejman; Schmitz, Christoph; Utzenrath, Marc; Sedaghat, Alexander; Fujita, Buntaro; Schmitz-Rode, Thomas; Ensminger, Stephan; Steinseifer, Ulrich

    2017-03-01

    Bioprosthetic aortic heart valves are increasingly implanted in younger patients. Therefore, a strategy for potential valve failure should be developed before implanting the 'first valve'. The goal of this in vitro study was to provide insight into the effects of the design of a bioprosthesis on a valve-in-valve implanted Sapien XT valve. The hydrodynamic performance of a 23-mm Sapien XT valve implanted in Vascutek Aspire, Edwards Perimount, Medtronic Mosaic and St. Jude Medical Trifecta heart valves was investigated in a left heart simulator. In addition to the hydrodynamic results, the leaflet dynamics were analysed in high-speed video recordings of the tests. All valve-in-valve combinations in this study fulfilled the minimum acceptance criteria defined by relevant approval standards (e.g. ISO 5840) but displayed significant differences in their performances. Small inner diameters of the bioprostheses were associated with increased mean pressure gradients, decreased effective orifice areas and geometric opening areas as well as with pin-wheeling and uneven leaflet motion. In addition, implantation in bioprostheses with internally mounted leaflets was associated with lower paravalvular leakage. The results of this study suggest that a surgical bioprosthesis with a large inner diameter and internally mounted leaflets improves the heamodynamics and potentially the durability of a valve-in-valve combination. These results should give the attending physicians critical information to consider when deciding on a bioprosthesis for younger patients.

  14. Analysis of tank safety with propane-butane on LPG distribution station

    Directory of Open Access Journals (Sweden)

    Krzysiak Zbigniew

    2017-12-01

    Full Text Available An analysis of the risk of failure in the safety valve – tank with propane-butane (LPG system has been conducted. An uncontrolled outflow of liquid LPG, caused by a failure of the above mentioned system has been considered as a threat. The main research goal of the study is the hazardous analysis of propane-butane gas outflow for the safety valve – LPG tank system. The additional goal is the development of an useful method to fast identify the hazard of a mismatched safety valve. The results of the research analysis have confirmed that safety valves are basic protection of the installation (tank against failures that can lead to loss of life, material damage and further undesired costs of their unreliability. That is why a new, professional computer program has been created that allows for the selection of safety valves or for the verification of a safety valve selection in installations where any technical or technological changes have been made.

  15. THE PROGNOSIS IN TRANSCATHETER AORTIC VALVE IMPLANTATION

    Directory of Open Access Journals (Sweden)

    T. E. Imaev

    2016-01-01

    Full Text Available Aim. To study the effect of transcatheter aortic valve implantation (TAVI, performed by different types of prostheses and various surgical access, on the prognosis of patients with critical aortic stenosis and comorbidities.Material and methods. Patients (n=130 that had consistently performed 80 TAVI by Edwards valve transfemoral (n=50 and transapical (n=30 access, as well as 50 transcatheter aortic valve replacement by CoreValve system were included into the study. Complications including perioperative mortality, total 30-day mortality, as well as post-hospital mortality were registered during aortic valve replacement, immediately after surgery, before the expiry of 30 days. Mean follow-up was 2.2 years (range 0.2 to 5.2 years.Results. Hospital mortality was on average 6.9%. 121 patients had been discharged from the department after the surgery. The number of deaths in the post-hospital period was 14.8%. Valve type and the type of access had no effect on post-hospital mortality. Men died more than 2.5 times often than women, regardless of age. Atrioventricular block, pacemaker implantation, and history of chronic obstructive pulmonary disease were the most significant prognostic factors. An important role of minor stroke and renal failure should be noted. Mortality did not depend on the surgical access or valve type. All parameters characterizing the intervention were significantly associated with mortality, both during and after surgery. The proportion of survivors at the end of the first year of observation using Corvalve system was 86.9%, Edwards valve by transfemoral access - 88% and Edwards valve by transapical access – 85.4% (insignificant differences for all groups, p>0.05. Two-year survival was 77.5%, 82.5% and 82.7%, respectively (also insignificant differences for all groups, p>0.05.Conclusion. TAVI is the method of choice, reasonable alternative approach for surgical valve replacement in patients with high surgical risk, although

  16. Transcatheter Aortic Valve Replacement With Early- and New-Generation Devices in Bicuspid Aortic Valve Stenosis

    DEFF Research Database (Denmark)

    Yoon, Sung Han; Lefèvre, Thierry; Ahn, Jung Ming

    2016-01-01

    Background Few studies have evaluated the clinical outcomes of transcatheter aortic valve replacement (TAVR) in patients with bicuspid aortic valve stenosis (AS). Particularly, limited data exist comparing the results of TAVR with new-generation devices versus early-generation devices.  Objective...

  17. Anterior mitral valve aneurysm perforation secondary to aortic valve endocarditis detected by Doppler colour flow mapping.

    Science.gov (United States)

    Decroly, P; Vandenbossche, J L; Englert, M

    1989-02-01

    We report a case of mitral valve aneurysm formation and perforation, secondary to Streptococcus sanguis endocarditis of the aortic valve. Aneurysm formation was documented by cross-sectional echocardiography and its perforation was established by Doppler colour flow mapping, and subsequently confirmed at surgery.

  18. In Vitro Evaluation of the iValve : A Novel Hands-Free Speech Valve

    NARCIS (Netherlands)

    van der Houwen, E.B.; van Kalkeren, T.A.; Burgerhof, J.G.; van der Laan, B.F.; Verkerke, G.J.

    2011-01-01

    Objectives: We performed in vitro evaluation of a novel, disposable, automatic hands-free tracheostoma speech valve for laryngectomy patients based upon the principle of inhalation. The commercially available automatic speech valves close upon strong exhalation and open again when the pressure

  19. Bjork-Shiley convexoconcave valves: Susceptibility artifacts at brain MR imaging and mechanical valve fractures

    NARCIS (Netherlands)

    van Gorp, Maarten J.; van der Graaf, Yolanda; de Mol, Bas A. J. M.; Bakker, Chris J. G.; Witkamp, Theo D.; Ramos, Lino M. P.; Mali, Willem P. T. M.

    2004-01-01

    PURPOSE: To assess the relationship between heart valve history and susceptibility artifacts at magnetic resonance (MR) imaging of the brain in patients with Bjork-Shiley convexoconcave (BSCC) valves. MATERIALS AND METHODS: MR images of the brain were obtained in 58 patients with prosthetic heart

  20. [Heart valve prosthesis and pregnancy].

    Science.gov (United States)

    Ben-Ismail, M; Fekih, M; Taktak, M; Chelli, M

    1979-02-01

    Sixteen pregnancies were followed up in 13 patients with prosthetic heart valves: 8 pregnancies went to term under oral anticoagulation, 4 under heparin and 4 without anticoagulation. 9 healthy normal children were delivered; there were 2 still births and 5 abortions. On the maternal side 3 haemorrhages and thromboembolic episodes which involved 2 patients on heparin, one of whom died, were observed. The following points are apparent from our observations and a review of the existing medical literature: --the risk of thromboembolism is not increased. The marked clotting tendency of maternal blood post-partum contraindicates the withdrawal of anticoagulants during this critical period; --haemorrhagic complications are common with anticoagulants; --foetal loss is greatly increased; --the teratogenecity of vitamin-K antagonists is certain, but the risk is small. The problems of anticoagulation are discussed; theoretically heparin should be given during the 1st trimestre and from the 38th week to the second post-partum week. The patients should be closely supervised by both obstetrician and cardiologist and hospitalisation is advised for the last month of pregnancy. Normal vaginal delivery is usually possible.

  1. Simplified surgical-hybrid Melody valve implantation for paediatric mitral valve disease.

    Science.gov (United States)

    Hofmann, Michael; Dave, Hitendu; Hübler, Michael; Kretschmar, Oliver

    2015-05-01

    Children suffering from left atrioventricular valve (LAVV) disease not amenable to repair represent a significant challenge. The results of surgical reconstruction are not optimal. Valve replacement as an alternative is associated with poor results. The surgical-hybrid approach with implantation of a stented biological valve (bovine jugular vein graft, Melody valve) seems to represent a new therapeutic option. Here we demonstrate our case, the consideration and the approach to extreme clinical findings in a small child. We describe a simplified surgical-hybrid Melody valve implantation in a LAVV position. The technique of implantation is relatively simple and the immediate postoperative result very good. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  2. The development of transcatheter aortic valve replacement in the USA.

    Science.gov (United States)

    Dvir, Danny; Barbash, Israel M; Ben-Dor, Itsik; Okubagzi, Petros; Satler, Lowell F; Waksman, Ron; Pichard, Augusto D

    2012-03-01

    The penetration rate of devices in general, and in transcatheter aortic valve replacement (TAVR) specifically, is significantly delayed in the United States of America (USA) compared with in Europe. This is mostly due to the mission statement of the regulatory agencies in the USA, which requires very rigorous clinical testing of a device prior to its approval. The USA had a major role in the development and evaluation of this technology and USA research has enabled clinicians inside and outside of the USA to conduct a concise scientifically based assessment of the performance of TAVR devices in terms of safety and efficacy. In the following review, we provide data on the development of TAVR in the USA, revealing the critical role the USA has played in this extraordinary process. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  3. Fluid Dynamic Characterization of a Polymeric Heart Valve Prototype (Poli-Valve) tested under Continuous and Pulsatile Flow Conditions

    Science.gov (United States)

    De Gaetano, Francesco; Serrani, Marta; Bagnoli, Paola; Brubert, Jacob; Stasiak, Joanna; Moggridge, Geoff D.; Costantino, Maria Laura

    2016-01-01

    Introduction Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy, the latter display better fluid dynamic behaviour but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the haemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of two groups of newly developed supra-annular tri-leaflet prosthetic heart valves made from styrenic block copolymers (SBC): Poli-Valves. Methods Two types of Poli-Valves made of SBC differing in polystyrene fraction content were tested under continuous and pulsatile flow conditions as prescribed by ISO 5840 Standard. An ad - hoc designed pulse duplicator allowed the valve prototypes to be tested at different flow rates and frequencies. Pressure and flow were recorded; pressure drops, effective orifice area (EOA), and regurgitant volume were computed to assess the valve’s behaviour. Results Both types Poli-Valves met the minimum requirements in terms of regurgitation and EOA as specified by ISO 5840 Standard. Results were compared with five mechanical heart valves (MHVs) and five tissue heart valves (THVs), currently available on the market. Conclusion Based on these results, polymeric heart valves based on styrenic block copolymers, as Poli-Valves are, can be considered as promising alternative for heart valve replacement in near future. PMID:26689146

  4. Effect of transcatheter aortic valve size and position on valve-in-valve hemodynamics: An in vitro study.

    Science.gov (United States)

    Azadani, Ali N; Reardon, Michael; Simonato, Matheus; Aldea, Gabriel; Nickenig, Georg; Kornowski, Ran; Dvir, Danny

    2017-06-01

    Transcatheter heart valve implantation in failed aortic bioprostheses (valve-in-valve [ViV]) is an increasingly used therapeutic option for high-risk patients. However, high postprocedural gradients are a significant limitation of aortic ViV. Our objective was to evaluate Medtronic CoreValve Evolut R ViV hemodynamics in relation to the degree of device oversizing and depth of implantation. Evolut R devices of 23 and 26 mm were implanted within 21-, 23-, and 25-mm Hancock II bioprostheses. Small and gradual changes in implantation depth were attempted. Hemodynamic testing was performed in a pulse duplicator under ISO-5840 standard. A total of 47 bench-testing experiments were performed. The mean gradient of the 26-mm Evolut R in 23- and 25-mm Hancock II was lower than 23-mm Evolut R (P  17.5 mm. The current comprehensive bench-testing assessment demonstrates the importance of both transcatheter heart valve size and device position for the attainment of optimal hemodynamics during ViV procedures. Additional in vitro testing may be required to develop hemodynamics-based guidelines for device sizing in ViV procedures in degenerated surgical bioprostheses. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  5. Pilot licensing after aortic valve surgery.

    Science.gov (United States)

    Syburra, Thomas; Schnüriger, Hans; Kwiatkowski, Barbara; Graves, Kirk; Reuthebuch, Oliver; Genoni, Michele

    2010-05-01

    Bicuspid aortic valve is the most common congenital heart malformation, and a high percentage of patients with this condition will develop complications over time. It is rare that pilots undergo aortic valve surgery, and the confirmation of flight-licensing requirements after aortic valve replacement (AVR) is a challenge for the patient's cardiac surgeon and, particularly, for the Aeromedical Examiner (AME). Only AMEs are able to determine the flight status of pilots. Furthermore, in military and in civil aviation (e.g., Red Bull Air Race), the high G-load environment experienced by pilots is an exceptional physiological parameter, which must be considered postoperatively. A review was conducted of the aeronautical, surgical and medical literature, and of European pilot-licensing regulations. Case studies are also reported for two Swiss Air Force pilots. According to European legislation, pilots can return to flight duty from the sixth postoperative month, with the following limitations: that an aortic bioprosthesis presents no restrictions in cardiac function, requires no cardioactive medications, yet requires a flight operation with co-pilot, the avoidance of accelerations over +3 Gz and, in military aviation, restricts the pilot to non-ejection-seat aircraft. The patient follow up must include both echocardiographic and rhythm assessments every six months. Mechanical prostheses cannot be certified because the required anticoagulation therapy is a disqualifying condition for pilot licensing. Pilot licensing after aortic valve surgery is possible, but with restrictions. The +Gz exposition is of concern in both military and civilian aviation (aerobatics). The choice of bioprosthesis type and size is determinant. Pericardial and stentless valves seem to show better flow characteristics under high-output conditions. Repetitive cardiological controls are mandatory for the early assessment of structural valve disease and rhythm disturbances. A pre-emptive timing is

  6. Lined 10'' butterfly valve outlasts competitive valves in brine filter system

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, A.

    1982-03-01

    One of the world's largest chlorine production units located in the Gulf Coast area has an extensive brine piping system with a large number of valves. Some of the valves performed well but many failed to meet the service requirements, especially in the brine filtering system with the salt solution at ambient temperatures and pressures about 100 psi. One of these was a 10'' valve. Various types of gear-operated butterfly valves, with an elastomer lining to withstand the somewhat corrosive solution, had been tried but developed leaks and had to be repaired or replaced after 4 to 6 months. The valves became difficult or impossible to operate in some cases when brine leaking past the stem seal attacked the inner surface of the metal valve body and the liner was dislodged by the movement of the disc. In September 1980, a 10'' butterfly valve specifically designed for bubble-tight shut off and zero stem leakage was installed in the brine filter line on a trial basis. The valve has a 1-piece, epoxy-coated ductile iron body with a molded one-piece liner of Hypalon rubber, and a stainless steel stem and disc with splines instead of pins to provide a trouble-free connection. The stem is positively sealed against leakage by a patented spherical machining process on both the disc and the liner. The valve was furnished with a variable ratio gear actuator that has higher torque output when the disc begins to make contact with the seat to assure a bubble-tight shutoff with minimum input torque. The butterfly valve has provided leaktight performance since it was installed in September 1980 and is still easy to open and close by the geared actuator.

  7. Loss of Axin2 results in impaired heart valve maturation and subsequent myxomatous valve disease.

    Science.gov (United States)

    Hulin, Alexia; Moore, Vicky; James, Jeanne M; Yutzey, Katherine E

    2017-01-01

    Myxomatous valve disease (MVD) is the most common aetiology of primary mitral regurgitation. Recent studies suggest that defects in heart valve development can lead to heart valve disease in adults. Wnt/β-catenin signalling is active during heart valve development and has been reported in human MVD. The consequences of increased Wnt/β-catenin signalling due to Axin2 deficiency in postnatal valve remodelling and pathogenesis of MVD were determined. To investigate the role of Wnt/β-catenin signalling, we analysed heart valves from mice deficient in Axin2 (KO), a negative regulator of Wnt/β-catenin signalling. Axin2 KO mice display enlarged mitral and aortic valves (AoV) after birth with increased Wnt/β-catenin signalling and cell proliferation, whereas Sox9 expression and collagen deposition are decreased. At 2 months in Axin2 KO mice, the valve extracellular matrix (ECM) is stratified but distal AoV leaflets remain thickened and develop aortic insufficiency. Progressive myxomatous degeneration is apparent at 4 months with extensive ECM remodelling and focal aggrecan-rich areas, along with increased BMP signalling. Infiltration of inflammatory cells is also observed in Axin2 KO AoV prior to ECM remodelling. Overall, these features are consistent with the progression of human MVD. Finally, Axin2 expression is decreased and Wnt/β-catenin signalling is increased in myxomatous mitral valves in a murine model of Marfan syndrome, supporting the importance of Wnt/β-catenin signalling in the development of MVD. Altogether, these data indicate that Axin2 limits Wnt/β-catenin signalling after birth and allows proper heart valve maturation. Moreover, dysregulation of Wnt/β-catenin signalling resulting from loss of Axin2 leads to progressive MVD. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.

  8. The sutureless aortic valve at 1 year: A large multicenter cohort study.

    Science.gov (United States)

    Fischlein, Theodor; Meuris, Bart; Hakim-Meibodi, Kavous; Misfeld, Martin; Carrel, Thierry; Zembala, Marian; Gaggianesi, Sara; Madonna, Francesco; Laborde, François; Asch, Federico; Haverich, Axel

    2016-06-01

    Sutureless aortic valve replacement (AVR) offers an alternative to standard AVR in aortic stenosis. This prospective, single-arm study aimed to demonstrate safety and effectiveness of a bovine pericardial sutureless aortic valve at 1 year. From February 2010 to September 2013, 658 patients (mean age 78.3 ± 5.6 years; 40.0% octogenarian; 64.4% female; mean Society of Thoracic Surgeons score 7.2 ± 7.4) underwent sutureless AVR in 25 European centers. Concomitant cardiac procedures were performed in 29.5% and minimally invasive cardiac surgery in 33.3%. One-year site-reported event rates were 8.1% for all-cause mortality, 4.5% for cardiac mortality, 3.0% for stroke, 1.9% for valve-related reoperation, 1.4% for endocarditis, and 0.6% for major paravalvular leak. No valve thrombosis, migration, or structural valve deterioration occurred. New York Heart Association class improved at least 1 level in 77.5% and remained stable (70.4% New York Heart Association class I or II at 1 year). Mean effective orifice area was 1.5 ± 0.4 cm(2); pressure gradient was 9.2 ± 5.0 mm Hg. Left ventricular mass decreased from 138.5 g/m(2) before surgery to 115.3 g/m(2) at 1 year (P < .001). Echocardiographic core laboratory findings confirmed that paravalvular leak was rare and remained stable during follow-up. The Perceval sutureless valve resulted in low 1-year event rates in intermediate-risk patients undergoing AVR. New York Heart Association class improved in more than three-quarters of patients and remained stable. These data support the safety and efficacy to 1 year of the Perceval sutureless valve in this intermediate-risk population. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  9. LMFBR large valve development. Comparison study of advantages and disadvantages of foreign design of offset pivot butterfly valves with AMCO's offset pivot ball valve

    Energy Technology Data Exchange (ETDEWEB)

    DeWall, L.

    1975-02-01

    The purpose of this effort was to compare the advantages and disadvantages of foreign designs of offset pivot butterfly valves presented during a specialists meeting on Operating Experience and Design Criteria of Sodium Valves with the characteristics of the present AMCO offset pivot ball valve design concept. In addition, the comparison was directed to indicating if work on a butterfly concept should be initiated by AMCO. This work could be in parallel with or in lieu of, the present AMCO effort on an offset pivot ball valve for isolation valve purposes.

  10. Durability of pericardial versus porcine bioprosthetic heart valves.

    Science.gov (United States)

    Grunkemeier, Gary L; Furnary, Anthony P; Wu, YingXing; Wang, Lian; Starr, Albert

    2012-12-01

    To compare the probability, and modes, of explantation for Carpentier-Edwards pericardial versus porcine valves. Our porcine series began in 1974 and our pericardial series in 1991, with annual prospective follow-up. We used the Kaplan-Meier method and Cox regression for estimation and analysis of patient mortality, and the cumulative incidence function and competing risks regression for estimation and analysis of valve durability. Through the end of 2010, we had implanted 506 porcine and 2449 pericardial aortic valves and 181 porcine and 163 pericardial mitral valves. The corresponding total and maximum follow-up years were 3471 and 24, 11,517 and 18, 864 and 22, and 645 and 9. The corresponding probabilities (cumulative incidence function) of any valve explant were 7%, 8%, 22%, and 8%, and of explant for structural valve deterioration were 4%, 5%, 16%, and 5% at 15 years for the first 3 series and at 8 years for the fourth (pericardial mitral valve) series. Using competing risks regression for structural valve deterioration explant, with age, gender, valve size, and concomitant coronary bypass surgery as covariates, a slight (subhazard ratio, 0.79), but nonsignificant, protective effect was found for the pericardial valve in the aortic position and a greater (subhazard ratio, 0.31) and almost significant (P = .08) protective effect of the pericardial valve in the mitral position. Leaflet tear was responsible for 61% of the structural valve deterioration explants in the porcine series and 46% in the pericardial series. Using competing risks regression, the pericardial valve had a subhazard ratio for structural valve deterioration explant of less than 1 in both positions, approaching statistical significance in the mitral position. The mode of structural valve deterioration was predominantly leaflet tear for porcine valves and fibrosis/calcification for pericardial valves. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc

  11. Survey of industrial coal conversion equipment capabilities: valves

    Energy Technology Data Exchange (ETDEWEB)

    Bush, W. A.; Slade, E. C.

    1978-06-01

    A survey of the industrial capabilities of the valve and valve-actuator industry to supply large, high-pressure stop valves for the future coal conversion industry is presented in this report. Also discussed are development and testing capabilities of valve and valve-actuator manufacturers and anticipated lead times required to manufacture advanced design valves for the most stringent service applications. Results indicate that the valve and valve-actuator industry is capable of manufacturing in quantity equipment of the size and for the pressure and temperature ranges which would be required in the coal conversion industry. Valve manufacturers do not, however, have sufficient product application experience to predict the continuing functional ability of valves used for lock-hopper feeders, slurry feeders, and slag-char letdown service. Developmental and testing efforts to modify existing valve designs or to develop new valve concepts for these applications were estimated to range from 1 to 6 years. A testing facility to simulate actuation of critical valves under service conditions would be beneficial.

  12. Cardiac crossroads: deciding between mechanical or bioprosthetic heart valve replacement

    Directory of Open Access Journals (Sweden)

    Maggie N Tillquist

    2011-02-01

    Full Text Available Maggie N Tillquist1, Thomas M Maddox21School of Medicine, University of Colorado Denver, Denver, CO, USA; 2VA Eastern Colorado Health Care System, and Department of Medicine (Cardiology, University of Colorado Denver, Denver, CO, USAAbstract: Nearly 15 million people in the United States suffer from either aortic or mitral valvular disease. For patients with severe and symptomatic valvular heart disease, valve replacement surgery improves morbidity and mortality outcomes. In 2009, 90,000 valve replacement surgeries were performed in the United States. This review evaluates the advantages and disadvantages of mechanical and bioprosthetic prosthetic heart valves as well as the factors for consideration in deciding the appropriate valve type for an individual patient. Although many caveats exist, the general recommendation is for patients younger than 60 to 65 years to receive mechanical valves due to the valve's longer durability and for patients older than 60 to 65 years to receive a bioprosthetic valve to avoid complications with anticoagulants. Situations that warrant special consideration include patient co-morbidities, the need for anticoagulation, and the potential for pregnancy. Once these characteristics have been considered, patients' values, anxieties, and expectations for their lifestyle and quality of life should be incorporated into final valve selection. Decision aids can be useful in integrating preferences in the valve decision. Finally, future directions in valve technology, anticoagulation, and medical decision-making are discussed.Keywords: prosthetic heart valves, patient preference, valve type, anticoagulant, structural valve deterioration 

  13. Valvular Heart Disease in Adults: Management of Prosthetic Heart Valves.

    Science.gov (United States)

    Trujillo, John F; Hollenberg, Steven M

    2017-06-01

    Patients undergoing cardiac valve replacement may receive mechanical or bioprosthetic valves. Mechanical valves require lifelong anticoagulation but are durable and the need for a second surgery is up to eightfold times less than with bioprosthetic valves. Bioprosthetic valves do not require lifelong anticoagulation and thus are associated with fewer bleeding complications but they are less durable and associated with higher morbidity and mortality rates, particularly in younger patients. Anticoagulation with mechanical valves is achieved using warfarin; use of direct-acting oral anticoagulants is not indicated. Concomitant low-dose aspirin is recommended for patients with mechanical valves and as sole thromboembolism prophylaxis for patients receiving aortic or mitral bioprosthetic valves. If a patient taking warfarin is to undergo a surgical procedure that requires interruption of anticoagulation, bridging therapy with heparin is indicated if the patient has a mechanical aortic valve and any risk of thromboembolism, an older-generation mechanical aortic valve, or a mechanical mitral valve. Warfarin is teratogenic; pregnant women should take heparin. Patients with mechanical or bioprosthetic valves should receive antibiotic prophylaxis before some dental and surgical procedures to prevent endocarditis. Thrombolytic therapy should be considered in patients who develop a thrombus on a valve that does not resolve with heparin. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  14. Evaluation of MRI issues at 3-Tesla for a transcatheter aortic valve replacement (TAVR) bioprosthesis.

    Science.gov (United States)

    Saeedi, Mahrad; Thomas, Asish; Shellock, Frank G

    2015-05-01

    Replacement of the aortic heart valve typically requires open-heart surgery. A new transcatheter aortic valve replacement (TAVR) bioprosthesis made from metallic material was recently developed that is an advantageous alternative insofar as it is implanted using a minimally invasive procedure. Because of the presence of metal, there are safety issues related to MRI. Therefore, the purpose of this study was to use standardized testing techniques to evaluate MRI issues for this TAVR bioprosthesis in association with a 3-Tesla MR system. The TAVR bioprosthesis (Hydra Aortic Valve, Percutaneous Heart Valve Prosthesis, Vascular Innovations Company, Ltd, Thailand) was evaluated for magnetic field interactions (translational attraction and torque), MRI-related heating at a relative high specific absorption rate level (whole body average SAR, 2.9-W/kg), and artifacts (T1-weighted, spin echo, and gradient echo pulse sequences) at 3-Tesla. The TAVR bioprosthesis demonstrated negligible magnetic field interactions (deflection angle, 3-degrees; torque, 0) and minimal heating (maximum temperature rise, 2.5°C; background temperature rise, 1.7°C). Artifacts were relatively small in relation to the size and shape of the implant. The TAVR bioprosthesis that was evaluated in this investigation is acceptable, or using current MRI terminology "MR Conditional", for a patient undergoing MRI at 3-Tesla or less. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Pars plana Ahmed valve and vitrectomy in patients with glaucoma associated with posterior segment disease.

    Science.gov (United States)

    Wallsh, Josh O; Gallemore, Ron P; Taban, Mehran; Hu, Charles; Sharareh, Behnam

    2013-01-01

    To assess the safety and efficacy of a modified technique for pars plana placement of the Ahmed valve in combination with pars plana vitrectomy in the treatment of glaucoma associated with posterior segment disease. Thirty-nine eyes with glaucoma associated with posterior segment disease underwent pars plana vitrectomy combined with Ahmed valve placement. All valves were placed in the pars plana using a modified technique, without the pars plana clip, and using a scleral patch graft. The 24 eyes diagnosed with neovascular glaucoma had an improvement in intraocular pressure from 37.6 mmHg to 13.8 mmHg and best-corrected visual acuity from 2.13 logarithm of minimum angle of resolution to 1.40 logarithm of minimum angle of resolution. Fifteen eyes diagnosed with steroid-induced glaucoma had an improvement in intraocular pressure from 27.9 mmHg to 14.1 mmHg and best-corrected visual acuity from 1.38 logarithm of minimum angle of resolution to 1.13 logarithm of minimum angle of resolution. Complications included four cases of cystic bleb formation and one case of choroidal detachment and explantation for hypotony. Ahmed valve placement through the pars plana during vitrectomy is an effective option for managing complex cases of glaucoma without the use of the pars plana clip.

  16. Mechanics of mitral valve edge-to-edge-repair and MitraClip procedure.

    Science.gov (United States)

    Bhattacharya, Shamik; He, Zhaoming

    2015-01-01

    The edge-to-edge repair (ETER) technique has been used as a stand-alone procedure, or as a secondary procedure with ring annuloplasty for degenerative, functional mitral regurgitation, or for mitral regurgitation of other kinds of valvular etiologies. The percutaneous MitraClip technique based on ETER has been used in patients who are inoperable or at high surgical risk. However, adverse events such as residual mitral regurgitation, and clip detachment or fracture indicate that the mechanics underlying these procedures is not well understood. Therefore, current studies on mitral valve functionality and mechanics related to the ETER and MitraClip procedures are reviewed to improve the efficacy and safety of both procedures. Extensive in vivo, in vitro, and in silico studies related to ETER and MitraClip procedures along with MitraClip clinical trial results are presented and discussed herein. The ETER suture force and the mitral valve tissue mechanics and hemodynamics of each procedure are discussed. A quantitative understanding of the interplay of mitral valve components and as to biological response to the procedures remains challenging. Based on mitral valve mechanics, ETER or MitraClip therapy can be optimized to enhance repair efficacy and durability.

  17.  A Novel V- Silicone Vestibular Stent: Preventing Vestibular Stenosis andPreserving Nasal Valves

    Directory of Open Access Journals (Sweden)

    Rashid Al Abri

    2012-01-01

    Full Text Available  This report presents a novel style of placing nasal stents. Patientsundergoing surgical procedures in the region of nasal vestibuleand nasal valves are at risk of developing vestibular stenosis andlifelong problems with the external and internal nasal valves;sequels of the repair. The objective of the report is to demonstratea simple and successful method of an inverted V- Stent placementto prevent potential complication of vestibular stenosis and nasalvalve compromise later in life. Following a fall on a sharp edge ofa metallic bed, a sixteen month old child with a deep laceratednasal wound extending from the collumellar base toward thetip of the nose underwent surgical exploration and repair of thenasal vestibule and nasal cavity. A soft silicone stent fashioned asinverted V was placed bilaterally. The child made a remarkablerecovery with no evidence of vestibular stenosis or nasal valveabnormalities. In patients with nasal trauma involving the nasalvestibule and internal and external nasal valves stent placementavoids sequels, adhesions, contractures, synechia vestibularstenosis and fibrosis involving these anatomical structures.The advantages of the described V- stents over the traditionalreadymade ridged nasal stents, tubing’s and composite aural graftsare: a technical simplicity of use, b safety, c less morbidity, dmore comfortable, and e economical. To our knowledge, this isthe first report of such a stent for prevention of vestibular stenosisand preserving nasal valves.

  18. Antithrombotic therapy for stroke prevention in atrial fibrillation and mechanical heart valves.

    Science.gov (United States)

    Eikelboom, John W; Hart, Robert G

    2012-05-01

    Cardioembolic strokes account for one-sixth of all strokes and are an important potentially preventable cause of morbidity and mortality. Vitamin K antagonists (e.g., warfarin) are effective for the prevention of cardioembolic stroke in patients with atrial fibrillation (AF) and in those with mechanical heart valves but because of their inherent limitations are underutilized and often suboptimally managed. Antiplatelet therapies have been the only alternatives to warfarin for stroke prevention in AF but although they are safer and more convenient they are much less efficacious. The advent of new oral anticoagulant drugs offers the potential to reduce the burden of cardioembolic stroke by providing access to effective, safe, and more convenient therapies. New oral anticoagulants have begun to replace warfarin for stroke prevention in some patients with AF, based on the favorable results of recently completed phase III randomized controlled trials, and provide for the first time an alternative to antiplatelet therapy for patients deemed unsuitable for warfarin. The promise of the new oral anticoagulants in patients with mechanical heart valves is currently being tested in a phase II trial. If efficacy and safety are demonstrated, the new oral anticoagulants will provide an alternative to warfarin for patients with mechanical heart valves and may also lead to increased use of mechanical valves for patients who would not have received them in the past because of the requirement for long term warfarin therapy. Copyright © 2012 Wiley Periodicals, Inc.

  19. Osseous and chondromatous metaplasia in calcific aortic valve stenosis.

    Science.gov (United States)

    Torre, Matthew; Hwang, David H; Padera, Robert F; Mitchell, Richard N; VanderLaan, Paul A

    2016-01-01

    Aortic valve replacement for calcific aortic valve stenosis is one of the more common cardiac surgical procedures. However, the underlying pathophysiology of calcific aortic valve stenosis is poorly understood. We therefore investigated the histologic findings of aortic valves excised for calcific aortic valve stenosis and correlated these findings with their associated clinical features. We performed a retrospective analysis on 6685 native aortic valves excised for calcific stenosis and 312 prosthetic tissue aortic valves with calcific degeneration at a single institution between 1987 and 2013. Patient demographics were correlated with valvular histologic features diagnosed on formalin-fixed, decalcified, and paraffin embedded hematoxylin and eosin stained sections. Of the analyzed aortic valves, 5200 (77.8%) were tricuspid, 1473 (22%) were bicuspid, 11 (0.2%) were unicuspid, and 1 was quadricuspid. The overall prevalence of osseous and/or chondromatous metaplasia was 15.6%. Compared to tricuspid valves, bicuspid valves had a higher prevalence of metaplasia (30.1% vs. 11.5%) and had an earlier mean age of excision (60.2 vs. 75.1 years old). In addition, the frequency of osseous metaplasia and/or chondromatous metaplasia increased with age at time of excision of bicuspid aortic valves, while tricuspid aortic valves showed the same incidence regardless of patient age. Males had a higher prevalence of metaplasia in both bicuspid (33.5% vs. 22.3%) and tricuspid (13.8% vs. 8.6%) aortic valves compared to females. Osseous metaplasia and/or chondromatous metaplasia was also more common in patients with bicuspid aortic valves and concurrent chronic kidney disease or atherosclerosis than in those without (33.6% vs. 28.3%). No osseous or chondromatous metaplasia was observed within the cusps of any of the prosthetic tissue valves. Osseous and chondromatous metaplasia are common findings in native aortic valves but do not occur in prosthetic tissue aortic valves. Bicuspid

  20. Block 4 and Cluster D - Safety

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    After transfer of Bloc4 test facility to SM18 its safety system was upgraded in 2014/2015 for its 3 existing test cryostats. In 2016 a new test facility HFM (High Field Magnet) was integrated in the Bloc4. A new test facility Cluster D which is similar to HFM is in a process of installation in SM18. The Presentation is dedicated to safety strategy of Bloc4 and Cluster D and focused on an analysis of risk conditions and on the real behaviour of safety valves in case of discharge. Protection of sub-atmospheric circuits is also discussed.

  1. Electrical Textile Valves for Paper Microfluidics.

    Science.gov (United States)

    Ainla, Alar; Hamedi, Mahiar M; Güder, Firat; Whitesides, George M

    2017-10-01

    This paper describes electrically-activated fluidic valves that operate based on electrowetting through textiles. The valves are fabricated from electrically conductive, insulated, hydrophobic textiles, but the concept can be extended to other porous materials. When the valve is closed, the liquid cannot pass through the hydrophobic textile. Upon application of a potential (in the range of 100-1000 V) between the textile and the liquid, the valve opens and the liquid penetrates the textile. These valves actuate in less than 1 s, require low energy (≈27 µJ per actuation), and work with a variety of aqueous solutions, including those with low surface tension and those containing bioanalytes. They are bistable in function, and are, in a sense, the electrofluidic analog of thyristors. They can be integrated into paper microfluidic devices to make circuits that are capable of controlling liquid, including autonomous fluidic timers and fluidic logic. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Radiological findings of congenital urethral valves

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Kyung Mo; Kook, Shin Ho [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1990-12-15

    Congenital urethral valve is the common cause of hydronephrosis in newborn infants and the most common cause of bladder outlet obstruction in male children. We reviewed and analysed radiological findings and associated anomalies of 16 cases of congenital urethral valve which were examined during the period from January 1985 to December 1989. The most frequent age was under one year old (56%). The main symptoms were urinary dribbing (37.5%), weak stream (25%) and urinary frequency and incontinence (25%). Anterior urethral valve (AUV) was 5 cases (31%) and posterior urethral valve (PUV) was 11 cases(69%), in which 10 cases were Type I and one case was Type III. Bladder wall thickening was seen in all cases and its severity was partly correlated with the degree of vesicoureteral reflux (VUR). VUR was observed in 12 cases (75%), and relatively severe in older age group. The degree of VUR was milder in AUV than PUV. Hydronephrosis was more severe in PUV than in anterior one, and its degree was correlated with the severity of VUR. Associated anomalies were ectopic urethral opening (2 cases), PDA (1 case), congenital megacolon (1 case) and patent urachus (1 case) in PUV. So early diagnosis and treatment of congenital urethral valve is essential to the prevention of renal damage.

  3. TCT-670 Optimal Transcatheter Heart Valve Sizing in Aortic Valve in Valve Implantation: Insights from the Valve in Valve International Data (VIVID) Registry

    DEFF Research Database (Denmark)

    Alnasser, Sami; Cheema, Asim N; Horlick, Eric

    2016-01-01

    )/true ID x 100. Results: A total of 595 patients (359 for standard size and 236 for oversized group) were included in the analysis. Baseline clinical, hemodynamic and surgical valve parameters were similar in these two groups. Both groups used similar THV devices in each matched comparison. The oversized.......1±8.1mmHg vs. 17.4±8.5mmHg, p=0.002) in comparison to the standard cohort. The oversized group however, had a higher rate of moderate to severe AI (6.9% vs. 2.7%, p=0.001) and second THV requirement (5.5%vs. 2.2%, p=0.04). THV mal-positioning, coronary obstruction and postoperative pacemaker requirement...

  4. Mechanical Designs for Relief Valves for Cryogenic Apparatuses and Installations

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    There are also pressure relief valves with warm seat available on which the set pressure is based on an adjustment of forces by permanent magnets. Pressure vessel rules allows also the choice for an active triggered pressure relief valve (Cont...

  5. Recognizing the Symptoms of Worsening Heart Valve Disease

    Science.gov (United States)

    ... be hard to separate our habits from the mechanics of our hearts, which is one important reason ... About Heart Valves • Heart Valve Problems and Causes • Risks, Signs and Symptoms Introduction Understanding Symptoms Recognizing Symptoms ...

  6. Prospective Multicenter Evaluation of the Direct Flow Medical Transcatheter Aortic Valve System: 12-Month Outcomes of the Evaluation of the Direct Flow Medical Percutaneous Aortic Valve 18F System for the Treatment of Patients With Severe Aortic Stenosis (DISCOVER) Study.

    Science.gov (United States)

    Lefèvre, Thierry; Colombo, Antonio; Tchétché, Didier; Latib, Azeem; Klugmann, Silvio; Fajadet, Jean; De Marco, Federico; Maisano, Francesco; Bruschi, Giuseppe; Bijuklic, Klaudija; Nava, Stefano; Weissman, Neil; Low, Reginald; Thomas, Martyn; Young, Christopher; Redwood, Simon; Mullen, Michael; Yap, John; Grube, Eberhard; Nickenig, Georg; Sinning, Jan-Malte; Hauptmann, Karl Eugen; Friedrich, Ivar; Lauterbach, Michael; Schmoeckel, Michael; Davidson, Charles; Schofer, Joachim

    2016-01-11

    The aim of this study was to assess the 1-year outcome after transcatheter aortic valve replacement (TAVR) of the Direct Flow Medical (DFM) valve in patients with severe symptomatic aortic stenosis who were contraindicated or high risk for surgery. The DFM transcatheter heart valve is a new-generation, nonmetallic aortic valve with a pressurized support structure and conformable double-ring annular sealing delivered through an 18-F sheath. The device allows repositioning, retrieval, and assessment of valve performance before permanent implantation. A prospective multicenter European registry was set up to determine the safety and performance of the valve in 100 consecutive patients (10 centers). Echocardiographic and angiographic data were evaluated by an independent core laboratory, and adverse events were adjudicated by a clinical events committee using Valve Academic Research Consortium criteria. Patients were 83.1 ± 5.9 years of age and had a logistic EuroSCORE of 22.5 ± 11.3% and a Society of Thoracic Surgeons score of 9.7 ± 8.7%. Correct valve positioning was obtained in 99% of cases with a combined 30-day safety endpoint at 10%, including major stroke in 5.0%, major vascular complications in 2.0%, and death in 1%. At 12 months, 95% of patients were in New York Heart Association functional class I or II. Freedom from any death was 90%, and freedom from any death or major stroke was 85%. Echocardiography demonstrated none/trace to mild aortic regurgitation in 100% of patients and an unchanged mean aortic gradient of 12.2 ± 6.6 mm Hg and effective orifice area of 1.6 ± 0.4 cm(2). At 1 year, the DFM transcatheter heart valve had durable hemodynamics. This study demonstrates that the low rate of early complications and the low risk of significant aortic regurgitation translated into midterm clinical benefit. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  7. TRINITY heart valve prosthesis: a novel repositionable and retrievable transapical transcatheter aortic valve system.

    Science.gov (United States)

    Hengstenberg, Christian; Condado, Jose; Garcia, David; Martinez, Milka Marin; La Forgia, Giambattista; Ebner, Adrian; Gallo, Santiago; Silva, Enrique; Holzamer, Andreas; Husser, Oliver; Hilker, Michael

    2015-03-01

    Transcatheter aortic valve implantation (TAVI) has become a viable option for selected high-risk patients with severe and symptomatic aortic stenosis. First- and second-generation TAVI devices are either self- or balloon-expandable, and are often not repositionable or not fully retrievable, leading to suboptimal positioning in some cases. This may result in paravalvular regurgitation, AV conduction delay, or compromise of coronary perfusion. A broader application of TAVI requires advances in both valve and delivery systems. Therefore, in order to facilitate accurate positioning, to minimise paravalvular leakage, possibly to reduce the risk of AV conduction delay, and possibly to be able to abort the procedure, a "next-generation" TAVI system has been developed which is repositionable and retrievable, the TRINITY heart valve system. The TRINITY heart valve system was implanted in a first-in-human study using the transapical approach to demonstrate feasibility and procedural success. All endpoints were adjudicated according to VARC definitions at seven and 30 days. The TRINITY heart valve system was implanted in a 74-year-old patient with severe symptomatic aortic valve stenosis. In this case, repositioning of the TRINITY resulted in optimal position without paravalvular leakage and with perfect function. The TRINITY heart valve is a repositionable and retrievable TAVI system. Both the implantation result and short-term clinical and haemodynamic outcome were excellent.

  8. Echocardiographic anatomy of the mitral valve in healthy dogs and dogs with myxomatous mitral valve disease.

    Science.gov (United States)

    Wesselowski, S; Borgarelli, M; Menciotti, G; Abbott, J

    2015-06-01

    To further characterize the echocardiographic anatomy of the canine mitral valve apparatus in normal dogs and in dogs affected by myxomatous mitral valve disease (MMVD). Twenty-two normal dogs and 60 dogs with MMVD were prospectively studied. The length (AMVL), width (AMVW) and area (AMVA) of the anterior mitral valve leaflet were measured in the control group and the affected group, as were the diameters of the mitral valve annulus in diastole (MVAd) and systole (MVAs). The dogs with MMVD were staged based on American College of Veterinary Internal Medicine (ACVIM) guidelines and separated into groups B1 and B2/C. All measurements were indexed to body weight based on empirically defined allometric relationships. There was a statistically significant relationship between all log10 transformed mitral valve dimensions and body weight. The AMVL, AMVW, AMVA, MVAd and MVAs were all significantly greater in the B2/C group compared to the B1 and control groups. The AMVW was also significantly greater in the B1 group compared to the control group. Interobserver % coefficient of variation (% CV) was mitral valve leaflet and the mitral valve annulus in the dog can be indexed to body weight based on allometric relationships. Preliminary reference intervals have been proposed over a range of body sizes. Relative to normal dogs, AMVL, AMVW, AMVA, MVAd and MVAs are greater in patients with advanced MMVD. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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.

  10. Compact UHV valve with field replaceable windows

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.D. (Brookhaven National Lab., Upton, NY (United States)); Freeman, J. (VAT, Inc., Woburn, MA (United States)); Powell, F. (Luxel, Inc., Friday Harbor, WA (United States))

    1991-01-01

    There are many applications in synchrotron radiation research where window valves can be usefully employed. Examples include gas cells for monochromator calibration, filters for high order light rejection, and as vacuum isolation elements between machine and experimental vacua. Often these devices are fairly expensive, and have only fixed (ie non-removable) windows. The development of a new type of seal technology by VAT for their series 01 valves provides a gate surface which is free from obstructions due to internal mechanical elements. This feature allows a threaded recess to be machined into the gate to receive a removable window frame which can carry standard size Luxel thin film windows. The combination of these features results in a DN 40 (2.75in. conflat flange) valve which provides a clear aperture of 21mm diameter for the window material. 8 refs., 2 figs.

  11. Cardiac Rehabilitation After Heart Valve Surgery

    DEFF Research Database (Denmark)

    Pollmann, Agathe Gerwina Elena; Frederiksen, Marianne; Prescott, Eva

    2017-01-01

    PURPOSE: Evidence of the effect of cardiac rehabilitation (CR) after heart valve surgery is scarce, but nevertheless CR is recommended for this group of patients. Therefore, this study assessed the effect of CR on exercise capacity, cardiovascular risk factors, and long-term mortality and morbidity......, as well as predictors for enrolment in or failing to complete CR. METHODS: A review of medical records identified 250 patients who underwent heart valve surgery between January 2009 and August 2013. Of these, 211 patients eligible for CR were identified. Effect of CR was assessed by peak oxygen uptake.......58-15.06). CONCLUSIONS: CR after heart valve surgery improved exercise capacity and was associated with reduced morbidity. Elderly and ethnic minorities were less likely to attend or complete CR and deserve special attention....

  12. Piezogenic pedal papules with mitral valve prolapse

    Directory of Open Access Journals (Sweden)

    Cihan Altin

    2016-01-01

    Full Text Available 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.

  13. Three-dimensional echocardiography in valve disease

    Directory of Open Access Journals (Sweden)

    Cesare Fiorentini

    2009-08-01

    Full Text Available This review covers the role of three-dimensional (3D echocardiography in the diagnosis of heart valve disease. Several factors have contributed to the evolution of this technique, which is currently a simple and routine method: rapid evolution in probe and computer technologies, demonstration that 3D data sets allowed more complete and accurate evaluation of cardiac structures, emerging clinical experience indicating the strong potential particularly in valve diseases, volume and function of the two ventricle measurements and several other fields. This report will review current and future applications of 3D echocardiography in mitral, aortic and tricuspid valve diseases underlying both qualitative (morphologic and quantitative advantages of this technique. (Heart International 2007; 3: 35-41

  14. Interlayer reliant magnetotransport in graphene spin valve

    Science.gov (United States)

    Iqbal, Muhammad Zahir; Hussain, Ghulam; Siddique, Salma; Iqbal, Muhammad Waqas

    2017-11-01

    Here the magnetotransport properties of vertical spin valve structures incorporating graphene (Gr), Gr/Au and Gr/Al2O3 intervening layers are elucidated. An in-plane magnetic field is obliquely applied to the device with the purpose to vary the relative magnetizations of ferromagnetic electrodes (Co and Ni). The relative magnetoresistance (MR) of Co/Gr/Ni is enhanced from ∼0.16% to 0.57% by simply passivating the bottom Ni electrode with thin Au film. On the other hand, depositing Al2O3 on the bottom ferromagnetic layer in such a spin valve junction not only increases the magnitude of MR (∼-0.52%) but also reverses its polarity. Furthermore, the linear current-voltage characteristics for graphene and graphene/Au spin valve devices specifies ohmic contact, while non-linear curves indicate tunneling behavior for graphene/Al2O3 device.

  15. Magneto-Seebeck effect in spin valves

    Science.gov (United States)

    Zhang, X. M.; Wan, C. H.; Wu, H.; Tang, P.; Yuan, Z. H.; Zhang, Q. T.; Zhang, X.; Tao, B. S.; Fang, C.; Han, X. F.

    2017-10-01

    The magneto-Seebeck (MS) effect, which is also called magneto-thermo-power, was observed in Co/Cu/Co and NiFe/Cu/Co spin valves. Their Seebeck coefficients in the parallel state were larger than those in the antiparallel state, and the MS ratio defined as (SAP -SP)/SP could reach -9% in our case. The MS effect originated not only from trivial giant magnetoresistance but also from spin current generated due to spin-polarized thermoelectric conductivity of ferromagnetic materials and subsequent modulation of the spin current by different spin configurations in spin valves. A simple Mott two-channel model reproduced a -11% MS effect for the Co/Cu/Co spin valves, qualitatively consistent with our observations. The MS effect could be applied for simultaneously sensing the temperature gradient and the magnetic field and also be possibly applied to determine spin polarization of thermoelectric conductivity and the Seebeck coefficient of ferromagnetic thin films.

  16. Exhaust gas bypass valve control for thermoelectric generator

    Science.gov (United States)

    Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter Jacobus; Anderson, Todd Alan

    2012-09-04

    A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

  17. AeroValve Experimental Test Data Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Noakes, Mark W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-09-01

    This report documents the collection of experimental test data and presents performance characteristics for the AeroValve brand prototype pneumatic bidirectional solenoid valves tested at the Oak Ridge National Laboratory (ORNL) in July/August 2014 as part of a validation of AeroValve energy efficiency claims. The test stand and control programs were provided by AeroValve. All raw data and processing are included in the report attachments.

  18. Modal-Based Design Improvement of a Butterfly Valve Disc

    OpenAIRE

    Marius Draghiciu; Zoltan-Iosif Korka; Gilbert-Rainer Gillich

    2017-01-01

    The dynamic behaviour control of a butterfly valve is important because, when one of the valve disc natural frequency is close to the frequency of vortex shedding, which appears when the valve is fully open or partially closed, resonance may appear and vibration with significant amplitudes is generated. This paper presents an example by how the design of a butterfly valve disc can be improved by using a modal analysis performed by means of the finite element method. For this purpose, the rese...

  19. Numerical study of cavitating flow inside a flush valve

    OpenAIRE

    BAYEUL-LAINE, Annie-Claude; Simonet, Sophie; DUTHEIL, Daniel; Caignaert, Guy

    2011-01-01

    In water supply installations, noise pollution often occurs. As a basic component of a system, a flush valve may frequently be a source of noise and vibration generated by cavitation or high turbulence levels. During valve closing or valve opening, cavitation can be a problem. In order to decrease the noise and to improve the design inside a flush valve, some experimental and numerical analyses were carried out in our laboratories. These analyses led to some improvements in the de...

  20. Surgery for rheumatic tricuspid valve disease: a 30-year experience.

    Science.gov (United States)

    Bernal, José M; Pontón, Alejandro; Diaz, Begoña; Llorca, Javier; García, Iván; Sarralde, Aurelio; Diago, Carmen; Revuelta, José M

    2008-08-01

    This study was undertaken to assess factors influencing short- and long-term outcomes of surgery for rheumatic disease of the tricuspid valve. Between 1974 and 2005, a total of 328 consecutive patients (mean age 51.3 +/- 13.6 years) underwent tricuspid valve surgery for rheumatic disease. There were 12 cases of isolated tricuspid lesion, 199 of triple-valve disease, 114 of tricuspid and mitral valve disease, and 3 of aortic and tricuspid valve disease. Most patients (72%) had predominantly tricuspid regurgitation. Tricuspid valve prosthetic replacement was performed in 31 cases and valve repair in 297. In-hospital mortality was 7.6%. Late mortality was 52.1%, whereas the expected mortality of the Spanish population of the same age was 24.2%. Predictors of in-hospital mortality were male sex, isolated tricuspid lesion, moderate aortic insufficiency, postclamping time, and tricuspid valve replacement. Mean follow-up was 8.7 years (range 1-31 years). Follow-up was 98.9% complete. Predictors of late mortality were age, New York Heart Association functional class IV, postclamping time, and mitral valve replacement. In total, 114 patients required valve reoperation, but only 4 (3.5%) for isolated tricuspid valve dysfunction. At 30 years, actuarial survival was 12.1% +/- 4.4%, actuarial freedom from reoperation was 27.5% +/- 5.8%, and actuarial freedom from valve-related complications was 2.0% +/- 1.3%. Organic tricuspid valve disease associated with rheumatic mitral or aortic lesions increases hospital and late mortality, but valve repair compared favorably with valve replacement. Long-term results may be considered acceptable for otherwise incurable valve disease.

  1. Morphological assessment of sucrose preservation for porcine heart valves.

    OpenAIRE

    Drury, P J; Olsen, E G; Ross, D N

    1982-01-01

    Porcine aortic valves stored in various concentrations of sucrose (50-80%) for up to 52 weeks were examined both histologically and by electron microscopy. The valves were compared with porcine aortic valves stored in a nutrient and antibiotic medium for 12 weeks. Overall preservation was better in those porcine valves stored in sucrose solution than in nutrient and antibiotic medium, the best preservation being in 50% sucrose. Despite wide separation of collagen at that concentration seen on...

  2. New PTFE gasket for butterfly shut-off valve enhances process reliability; Neue PTFE-Dichtung bei Absperrklappe steigert Prozesssicherheit

    Energy Technology Data Exchange (ETDEWEB)

    Jaeckle, Timo; Mayer, Karl-Heinz; Neye, Christian; Paul, Wolfgang [GF Piping Systems (Switzerland)

    2009-05-15

    In both in the chemicals processing industry and many other applications, valves very frequently come into contact with highly aggressive fluids. The advantages and disadvantages - or even the problems - of the valve materials used then become apparent very quickly. The safety, reliability and cost-efficiency of the valves used is decided, in particular, in the field of seal and gaskets. Fundamental properties, such as resistance to chemical attack, corrosion and temperature, and also permeation rates, must be taken into account for all the materials used. These influencing factors become even more vital as temperatures and/or fluid concentrations increase. Mixtures of acids, and also cleaning processes, have again and again proven to be extremely critical. (orig.)

  3. Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease

    DEFF Research Database (Denmark)

    Mylotte, Darren; Lefevre, Thierry; Søndergaard, Lars

    2014-01-01

    (16.7% balloon-expandable THV vs. 17.6% self-expandable THV, p = 0.99). MSCT sizing was associated with reduced AR on multivariate analysis (odds ratio [OR]: 0.19, 95% confidence intervals [CI]: 0.08 to 0.45; p device safety, success, and efficacy were noted in 79.1%, 89......, a high incidence of post-implantation AR is observed, which appears to be mitigated by MSCT-based TAV sizing. Given the suboptimal echocardiographic results, further study is required to evaluate long-term efficacy....

  4. Incidence, predictors, origin and prevention of early and late neurological events after transcatheter aortic valve implantation (TAVI): a comprehensive review of current data.

    Science.gov (United States)

    Kahlert, Philipp; Al-Rashid, Fadi; Plicht, Björn; Hildebrandt, Heike; Patsalis, Polykarpos; Chilali, Karim El; Wendt, Daniel; Thielmann, Matthias; Bergmann, Lars; Kottenberg, Eva; Schlamann, Marc; Eggebrecht, Holger; Jakob, Heinz; Heusch, Gerd; Konorza, Thomas; Erbel, Raimund

    2013-05-01

    Transcatheter aortic valve implantation (TAVI) is a novel treatment option for patients with severe, symptomatic aortic valve stenosis considered inoperable or at high risk for surgical aortic valve replacement. Despite rapid adoption of this technology into clinical application, however, recent randomized controlled clinical trials have raised safety concerns regarding an increased risk of neurological events with TAVI compared to both medical treatment and conventional, surgical aortic valve replacement. Moreover, neuro-imaging studies have revealed an even higher incidence of new, albeit clinically silent cerebral lesions as a surrogate for procedural embolization. In this article, we review currently available data on the incidence, timing, predictors, prognostic implications and potential mechanisms of neurological events after TAVI.

  5. Experimental apparatus to test air trap valves

    Science.gov (United States)

    Lemos De Lucca, Y. de F.; de Aquino, G. A.; Filho, J. G. D.

    2010-08-01

    It is known that the presence of trapped air within water distribution pipes can lead to irregular operation or even damage to the distribution systems and their components. The presence of trapped air may occur while the pipes are being filled with water, or while the pumping systems are in operation. The formation of large air pockets can produce the water hammer phenomenon, the instability and the loss of pressure in the water distribution networks. As a result, it can overload the pumps, increase the consumption of electricity, and damage the pumping system. In order to avoid its formation, all of the trapped air should be removed through "air trap valves". In Brazil, manufacturers frequently have unreliable sizing charts, which cause malfunctioning of the "air trap valves". The result of these malfunctions causes accidents of substantial damage. The construction of a test facility will provide a foundation of technical information that will be used to help make decisions when designing a system of pipelines where "air trap valves" are used. To achieve this, all of the valve characteristics (geometric, mechanic, hydraulic and dynamic) should be determined. This paper aims to describe and analyze the experimental apparatus and test procedure to be used to test "air trap valves". The experimental apparatus and test facility will be located at the University of Campinas, Brazil at the College of Civil Engineering, Architecture, and Urbanism in the Hydraulics and Fluid Mechanics laboratory. The experimental apparatus will be comprised of various components (pumps, steel pipes, butterfly valves to control the discharge, flow meter and reservoirs) and instrumentation (pressure transducers, anemometer and proximity sensor). It should be emphasized that all theoretical and experimental procedures should be defined while taking into consideration flow parameters and fluid properties that influence the tests.

  6. Experimental apparatus to test air trap valves

    Energy Technology Data Exchange (ETDEWEB)

    Lemos De Lucca, Y de F [CTH-DAEE-USP/FAAP/UNICAMP (Brazil); Aquino, G A de [SABESP/UNICAMP (Brazil); Filho, J G D, E-mail: yvone.lucca@gmail.co [Water Resources Department, University of Campinas-UNICAMP, Av. Albert Einstein, 951, Cidade Universitaria-Barao Geraldo-Campinas, S.P., 13083-852 (Brazil)

    2010-08-15

    It is known that the presence of trapped air within water distribution pipes can lead to irregular operation or even damage to the distribution systems and their components. The presence of trapped air may occur while the pipes are being filled with water, or while the pumping systems are in operation. The formation of large air pockets can produce the water hammer phenomenon, the instability and the loss of pressure in the water distribution networks. As a result, it can overload the pumps, increase the consumption of electricity, and damage the pumping system. In order to avoid its formation, all of the trapped air should be removed through 'air trap valves'. In Brazil, manufacturers frequently have unreliable sizing charts, which cause malfunctioning of the 'air trap valves'. The result of these malfunctions causes accidents of substantial damage. The construction of a test facility will provide a foundation of technical information that will be used to help make decisions when designing a system of pipelines where 'air trap valves' are used. To achieve this, all of the valve characteristics (geometric, mechanic, hydraulic and dynamic) should be determined. This paper aims to describe and analyze the experimental apparatus and test procedure to be used to test 'air trap valves'. The experimental apparatus and test facility will be located at the University of Campinas, Brazil at the College of Civil Engineering, Architecture, and Urbanism in the Hydraulics and Fluid Mechanics laboratory. The experimental apparatus will be comprised of various components (pumps, steel pipes, butterfly valves to control the discharge, flow meter and reservoirs) and instrumentation (pressure transducers, anemometer and proximity sensor). It should be emphasized that all theoretical and experimental procedures should be defined while taking into consideration flow parameters and fluid properties that influence the tests.

  7. [Quality in aortic valve replacement--how good have hybrid valves have to be?].

    Science.gov (United States)

    Aicher, D; Groesdonk, H V; Schäfers, H-J

    2009-10-01

    The current enthusiasm with the development of catheter-based aortic valve replacement suggests a critical appraisal of the quality of conventional techniques. Currently surgical treatment of diseased aortic valves includes different methods that can be employed with a low risk. Risk prediction is difficult, the Euroscore largely overestimates mortality. By comparison, there is no evidence that the risk of implantation is reduced by catheter-based implantation. Specific complications (stroke, AV-block, perivalvular leak) are more frequent compared to conventional replacement. Despite the current enthusiasm over the feasibility of catheter-based implantation of hybrid aortic valves they should still be used cautiously. Georg Thieme Verlag KG Stuttgart, New York.

  8. Assessment of slurry pressure letdown valve and slurry block valve technology for direct coal liquefaction demonstration and pioneer commercial plants

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, R.P.

    1984-10-01

    This report examines the status of the technology of high pressure slurry letdown valves and slurry block valves in coal liquefaction service. All of the demonstration and pioneer commercial direct liquefaction plant designs call for the use of high pressure slurry letdown valves for flow control and slurry block valves for flow isolation. Successful performance and reliability of these valves is a serious concern because of the severity of the process streams and the limited experience and performance data on these valves under such conditions. The objectives of this report are: (1) to examine the existing data base on these valves from the four major direct coal liquefaction pilot plants in the US, (2) to present the recommendations from the pilot plant experience, (3) to examine the specifications for the letdown and block valves in the demonstration/pioneer commercial designs, and (4) to identify the scale-up issues, data gaps, and development and testing needs. 23 references, 20 figures, 7 tables.

  9. Remote operated valves - the Bolivian approach

    Energy Technology Data Exchange (ETDEWEB)

    Cuellar, O.; Arce, G.; Blanco, E.; Collazos, A.; Chavarria, E. [Transredes S.A., Transporte de Hidrocarburos, La Paz (Bolivia)

    2005-07-01

    For pipeline operators, the Remote Operated Valves (ROV) are tools to isolate pipe segments and contain any potential spill and they are also useful tools to provide data on operating conditions. Projects and articles about the locations and site layouts were developed to install Remote Operated Valves and the criteria for their use; each location has its own environmental, social and logistical particulars. This article describes the approach used to install ROV in Bolivia and the final design installed discussions and lessons learned about the: criteria to define the location, layout equipment installed and shelter and particulars of the location. (author)

  10. Left Ventricular Pseudoaneurysm after Valve Replacement

    Directory of Open Access Journals (Sweden)

    Jun Ho Lee

    2015-02-01

    Full Text Available We present a case of left ventricular pseudoaneurysm, which is a very rare and fatal complication of cardiac procedures such as mitral valve replacement. A 55-year-old woman presented to the Department of Thoracic and Cardiovascular Surgery at Hanyang University Seoul Hospital with chest pain. Ten years prior, the patient had undergone double valve replacement due to aortic regurgitation and mitral steno-insufficiency. Surgical repair was successfully performed using a prosthetic pericardial patch via a left lateral thoracotomy.

  11. The serpentine mitral valve and cerebral embolism

    Directory of Open Access Journals (Sweden)

    Ker James

    2011-02-01

    Full Text Available Abstract Valvular strands, well-delineated filiform masses, attached to cardiac valve edges are associated with cerebral embolism and stroke. Strokes, caused by emboli from valvular strands, tend to occur among younger persons. In this case report a valvular strand, giving a peculiar serpentine appearance to the mitral valve is described. This mitral valvular strand was the only explanation for an episode of cerebral embolism, presenting with a transient right sided hemiparesis. It is proposed that a randomized study involving combined treatment with aspirin and clopidogrel is warranted in young patients with valvular strands, presenting with a first episode of cerebral embolism.

  12. Torque limited drive for manual valves

    Science.gov (United States)

    Elliott, Philip G.; Underwood, Daniel E.

    1989-01-01

    The present invention is directed to a torque-limiting handwheel device for preventing manual valves from being damaged due to the application of excessive torque during the opening or closing operation of the valves. Torque can only be applied when ridges in the handwheel assembly engage in channels machined in the face of the baseplate. The amount of torque required for disengagement of the ridges from the channels is determined by the force exerted by various Bellville springs and the inclination of the side faces of the channels.

  13. Computer tomographic findings in mitral valve disease

    Energy Technology Data Exchange (ETDEWEB)

    Heuser, L.; Neufang, K.F.R.; Jansen, W.

    1984-04-01

    In 38 patients suffering from mitral valve disease the findings of cardiac CT scans were compared to the results of echocardiographic, standard roentgenographic, and cineangiocardiographic studies as well as to intraoperative and histological findings. CT proved to be superior to the other imaging modalities in detecting mitral calcifications and in demonstrating the morphological changes, but cannot replace cardiac catheterization as it does not yield haemodynamic data. The indication for CT in mitral valve disease therefore is restricted to cases with extremely enlarged left atria in which the other methods do not provide satisfactory visualization, and to patients with suspected intracavitary thrombus or tumor. 8 figs.

  14. Multimodality Imaging of Heart Valve Disease

    Energy Technology Data Exchange (ETDEWEB)

    Rajani, Ronak, E-mail: Dr.R.Rajani@gmail.com [Department of Cardiology, St. Thomas’ Hospital, London (United Kingdom); Khattar, Rajdeep [Department of Cardiology, Royal Brompton Hospital, London (United Kingdom); Chiribiri, Amedeo [Divisions of Imaging Sciences, The Rayne Institute, St. Thomas' Hospital, London (United Kingdom); Victor, Kelly; Chambers, John [Department of Cardiology, St. Thomas’ Hospital, London (United Kingdom)

    2014-09-15

    Unidentified heart valve disease is associated with a significant morbidity and mortality. It has therefore become important to accurately identify, assess and monitor patients with this condition in order that appropriate and timely intervention can occur. Although echocardiography has emerged as the predominant imaging modality for this purpose, recent advances in cardiac magnetic resonance and cardiac computed tomography indicate that they may have an important contribution to make. The current review describes the assessment of regurgitant and stenotic heart valves by multimodality imaging (echocardiography, cardiac computed tomography and cardiac magnetic resonance) and discusses their relative strengths and weaknesses.

  15. Autonomous valve for detection of biopolymer degradation

    DEFF Research Database (Denmark)

    Keller, Stephan Urs; Noeth, Nadine-Nicole; Fetz, Stefanie

    2009-01-01

    We present a polymer microvalve that allows the detection of biopolymer degradation without the need of external energy. The valve is based on a polymer container filled with a colored marker solution and closed by a thin lid. This structure is covered by a film of poly(L-lactide) and degradation...... of the biopolymer triggers the release of the color which is detected visually. The autonomous valve has potential for the fast testing of biopolymer degradation under various environmental conditions or by specific enzymes....

  16. Pregnancy Outcomes in Women With Aortic Valve Substitutes

    NARCIS (Netherlands)

    Heuvelman, Helena J.; Arabkhani, Bardia; Cornette, Jerome M. J.; Pieper, Petronella G.; Bogers, Ad J. J. C.; Takkenberg, Johanna J. M.; Roos-Hesselink, Jolien W.

    2013-01-01

    Young women who require aortic valve replacement need information on the potential cardiac and obstetric complications of pregnancy for the different valve substitutes available. We, therefore, assessed the pregnancy outcomes in women who had received an autograft, homograft, or mechanical valve in

  17. The Bundle of His in Prosthetic Heart Valve Replacement*

    African Journals Online (AJOL)

    1973-01-27

    Jan 27, 1973 ... sudden deaths which occur following heart valve replace- ment. In our local cardiac surgery unit at Groote Schuur. Hospital, the hospital mortality rate for aortic valve replacement with the University of Cape Town (VeT) aortic valve prosthesis between March 1963 and October. 1968, was 120. 0 according to ...

  18. Intermittent intravalvar regurgitation of a mechanical aortic valve ...

    African Journals Online (AJOL)

    Mechanical prosthetic valve regurgitation may be either periprosthetic or intraprosthetic. The later is usually mild, occurring in the majority of normally functioning valves and is due to the 'regurgitant flow' closing the valve. An unusual case is reported of intermitent intraprosthetic regurgitation through a normally functioning ...

  19. Low-power piezoelectric micro-machined valve

    Science.gov (United States)

    Gianchandani, Yogesh B. (Inventor); Nellis, Gregory Francis (Inventor); Klein, Sanford A. (Inventor); Park, John Moon (Inventor); Evans, Allan Thomas (Inventor); Taylor, Ryan (Inventor); Brosten, Tyler R. (Inventor)

    2010-01-01

    A piezoelectric microvalve employs a valve element formed of hermetically sealed and opposed plates flexed together by a cross axis piezoelectric element. Large flow modulation with small piezoelectric actuator displacement is obtained by perimeter augmentation of the valve seat which dramatically increases the change in valve flow area for small deflections.

  20. 49 CFR 230.52 - Water glass valves.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Water glass valves. 230.52 Section 230.52... Water Glasses and Gauge Cocks § 230.52 Water glass valves. All water glasses shall be equipped with no more than two valves capable of isolating the water glass from the boiler. They shall also be equipped...

  1. The Heimlich Valve for Pleural Cavity Drainage | Makanga | Annals ...

    African Journals Online (AJOL)

    One-way valve systems such as the Heimlich valve are small, portable apparatus that allow regulation of fluid flow and require minimal nursing care other than daily charting. Methods: A retrospective descriptive analysis of all chest drains connected to a Heimlich valve between January 2009 and December 2012. Data on ...

  2. 46 CFR 154.546 - Excess flow valve: Closing flow.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Excess flow valve: Closing flow. 154.546 Section 154.546... and Process Piping Systems § 154.546 Excess flow valve: Closing flow. (a) The rated closing flow of vapor or liquid cargo for an excess flow valve must be specially approved by the Commandant (CG-522). (b...

  3. The Warm, Rich Sound of Valve Guitar Amplifiers

    Science.gov (United States)

    Keeports, David

    2017-01-01

    Practical solid state diodes and transistors have made glass valve technology nearly obsolete. Nevertheless, valves survive largely because electric guitar players much prefer the sound of valve amplifiers to the sound of transistor amplifiers. This paper discusses the introductory-level physics behind that preference. Overdriving an amplifier…

  4. Perioperative anticoagulation for children with prosthetic mechanical valves

    OpenAIRE

    Grech, Victor E.; Rees, Philip G.

    2000-01-01

    The insertion of a mechanical heart valve predisposes to thrombosis and embolism, and for this reason, individuals with mechanical valves who undergo dental/surgical procedures must take special precautions. In this article, we illustrate a protocol for anticoagulation during such procedures in individuals with mechanical valves.

  5. The balloon-expandable Edwards Sapien 3 valve is superior to the self-expanding Medtronic CoreValve in patients with severe aortic stenosis undergoing transfemoral aortic valve implantation.

    Science.gov (United States)

    Gonska, Birgid; Seeger, Julia; Baarts, Justus; Rodewald, Christoph; Scharnbeck, Dominik; Rottbauer, Wolfgang; Wöhrle, Jochen

    2017-06-01

    Residual paravalvular moderate or severe aortic regurgitation (AR) has been an independent risk factor for mortality after transcatheter aortic valve implantation (TAVI). The design of the third generation Edwards Sapien 3 (ES3; Edwards Lifesciences, Irvine, CA, USA) valve was optimized with an outer skirt to address the issue of paravalvular AR. We compared 100 consecutive patients treated with the ES3 for severe aortic stenosis with 100 patients treated with the Medtronic CoreValve (CV; Medtronic, Minneapolis, MN, USA) (Clinical Trial Registration: NCT02162069). We evaluated post-procedural AR, rate of permanent pacemaker implantation, device success, and 30-day clinical outcome according to the criteria of the Second Valve Academic Research Consortium (VARC-2). Frequency of post-procedural moderate or severe AR was significantly lower with ES3 compared to CV (0% vs. 20%, p<0.01), none or trace AR significantly higher with ES3 (69% vs. 38%, p<0.01) as well as device success (97% vs. 73%, p<0.01). There was a significantly lower need for permanent pacemaker implantation with ES3 compared with CV (14% vs. 31%, p<0.01). Cardiovascular mortality at 30 days was significantly lower with ES3 (0% vs. 6%, p=0.01), and the combined endpoint "early safety" was met significantly less with ES3 (10% vs. 21% with CV, p=0.03). Transfemoral TAVI with the ES3 compared with the CV was associated with a significantly lower rate of moderate or severe AR, significantly lower need for pacemaker implantation, and a significantly higher rate of device success according to VARC-2. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  6. Experimental substantiation of the design of a prosthetic heart valve for «valve-in-valve» implantation

    Directory of Open Access Journals (Sweden)

    K. Yu. Klyshnikov

    2017-01-01

    Full Text Available The aim of the study was to perform a series of in vitro tests of a prototype of the developing heart valve prosthesis to evaluate its functional characteristics. Materials and methods. In this work we have used the frames and full prototypes of the prosthesis, consisting of a stent-like stainless steel support frame with mounted biological leaflets and cover. The authors evaluated the calculated and experimental forces necessary for the displacement of the sutureless implanted prosthesis using the test machine under uniaxial tension. The risk of defects and damages to the supporting framework as a result of implantation was evaluated by scanning electron microscopy. The hydrodynamic characteristics of the prosthesis were investigated under physiological conditions and «valvein-valve» implantation. Evaluation of the ergonomics and applicability of the proposed construction on the cadaver heart model of cattle was carried out. Results. As a result of the forces assessment, it was found that the force required to shear the prosthesis was 3.12 ± 0.37 N, while the calculated value was 1.7 N, which is significantly lower than the obtained value. The comparison of the images obtained with small and large magnifications demonstrated the absence of critical surface defects. Additional analysis under the super-large magnifications also did not reveal problem areas. During the hydrodynamic study, it was shown that the average transplant gradient increased slightly from 2.8–3.4 to 3.2–4.5 mm Hg for the initial prosthesis and the «valve-in-valve» complex, respectively. The decrease of the effective orifice area was 6–9% relative to the initial one. Evaluation of the implantation technique demonstrated the consistency of the approach: the use of the developed holder in combination with the balloon implantation system made it possible to position the prosthesis throughout the procedure. Conclusion. The series of tests demonstrates the consistency

  7. Drug Safety

    Science.gov (United States)

    ... over-the-counter drug. The FDA evaluates the safety of a drug by looking at Side effects ... clinical trials The FDA also monitors a drug's safety after approval. For you, drug safety means buying ...

  8. Modeling and Investigation of Electromechanical Valve Train Actuator at simulated Pressure conditions

    DEFF Research Database (Denmark)

    Habib, Tufail

    2012-01-01

    In an electromechanical valve actuated engine, the valves are driven by solenoid-type actuators and cam-shaft is eliminated. Control of each valve provides flexibility in valve timings over all engine conditions and achieves the benefits of variable valve timing(VVT). This paper is about investig......In an electromechanical valve actuated engine, the valves are driven by solenoid-type actuators and cam-shaft is eliminated. Control of each valve provides flexibility in valve timings over all engine conditions and achieves the benefits of variable valve timing(VVT). This paper is about...

  9. Concomitant mitral valve surgery with aortic valve replacement: a 21-year experience with a single mechanical prosthesis

    Directory of Open Access Journals (Sweden)

    Sidhu Pushpinder

    2007-05-01

    Full Text Available Abstract Background Long-term survival for combined aortic and mitral valve replacement appears to be determined by the mitral valve prosthesis from our previous studies. This 21-year retrospective study assess long-term outcome and durability of aortic valve replacement (AVR with either concomitant mitral valve replacement (MVR or mitral valve repair (MVrep. We consider only a single mechanical prosthesis. Methods Three hundred and sixteen patients underwent double valve replacement (DVR (n = 273 or AVR+MVrep (n = 43, in the period 1977 to 1997. Follow up of 100% was achieved via telephone questionnaire and review of patients' medical records. Actuarial analysis of long-term survival was determined by Kaplan-Meier method. The Cox regression model was used to evaluate potential predictors of mortality. Results There were seventeen cases (5.4% of early mortality and ninety-six cases of late mortality. Fifteen-year survival was similar in both groups at 44% and 57% for DVR and AVR+MVrep respectively. There were no significant differences in valve related deaths, anticoagulation related complications, or prosthetic valve endocarditis between the groups. There were 6 cases of periprosthetic leak in the DVR group. Sex, pre-operative mitral and aortic valve pathology or previous cardiac surgery did not significantly affect outcome. Conclusion The mitral valve appears to be the determinant of survival following double valve surgery and survival is not significantly influenced by mitral valve repair.

  10. Magnetic-adhesive based valves for microfluidic devices used in low-resource settings.

    Science.gov (United States)

    Harper, Jason C; Andrews, Jenna M; Ben, Candice; Hunt, Andrew C; Murton, Jaclyn K; Carson, Bryan D; Bachand, George D; Lovchik, Julie A; Arndt, William D; Finley, Melissa R; Edwards, Thayne L

    2016-10-18

    Since the introduction of micro total analytical systems (μTASs), significant advances have been made toward development of lab-on-a-chip platforms capable of performing complex biological assays that can revolutionize public health, among other applications. However, use of these platforms in low-resource environments (e.g. developing countries) has yet to be realized as the majority of technologies used to control microfluidic flow rely on off-device hardware with non-negligible size, cost, power requirements and skill/training to operate. In this paper we describe a magnetic-adhesive based valve that is simple to construct and operate, and can be used to control fluid flow and store reagents within a microfluidic device. The design consists of a port connecting two chambers on different planes in the device that is closed by a neodymium disk magnet seated on a thin ring of adhesive. Bringing an external magnet into contact with the outer surface of the device unseats and displaces the valve magnet from the adhesive ring, exposing the port. Using this configuration, we demonstrate on-device reagent storage and on-demand transport and reaction of contents between chambers. This design requires no power or external instrumentation to operate, is extremely low cost ($0.20 materials cost per valve), can be used by individuals with no technical training, and requires only a hand-held magnet to actuate. Additionally, valve actuation does not compromise the integrity of the completely sealed microfluidic device, increasing safety for the operator when toxic or harmful substances are contained within. This valve concept has the potential to simplify design of μTASs, facilitating development of lab-on-a-chip systems that may be practical for use in point-of-care and low-resource settings.

  11. Obstructive Thrombosis of Left-Sided Mechanical Heart Valves: Clinical Profile and Thrombolytic Therapy.

    Science.gov (United States)

    Chandrakasu, Arumugam; Jayachandran, Avinash; Gopinath Nayar, Pradeep; Meyyappan, Chokkalingam; Narayan, Ganesh; Basha Abdul Bari, Ahamed; Johnson Samuel, Prince

    2017-05-01

    Thrombosis of a mechanical prosthetic heart valve is a potentially life-threatening complication associated with a high mortality. Although thrombolytic therapy has been considered highly beneficial in this situation, very few studies have been conducted to monitor the effectiveness of such thrombolytic therapy among Asian populations. Hence, the study aim was to evaluate the clinical profile, efficacy and safety of the thrombolytic agent streptokinase (SK) in patients with obstructive thrombosis of a left-sided mechanical heart valve. Patients (n = 30) with left-sided mechanical heart valve thrombosis (LSMHVT) who had been managed with SK during the past four years were included in this retrospective study. Clinical features such as presenting symptoms based on NYHA functional class, prosthetic valve position, oral anticoagulant compliance, International Normalized Ratio (INR) and imaging methods including fluoroscopy, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were evaluated. In addition, the effectiveness and complications of SK were analyzed. The majority of patients presented with advanced NYHA class (III and IV, each 40%). Obstructive thromboses were observed at the mitral prosthesis in 70% of cases, at the aortic prosthesis in 27%, and at both valves in 3%. All patients underwent TTE, but fluoroscopy was used more often than TEE. Despite compliance with oral anticoagulation therapy, a sub-therapeutic INR was observed in 40% of cases at the time of presentation. Overall, thrombolysis was successful in 80% of patients using intravenous SK, with 100% success in patients in NYHA classes I-III and 42% for NYHA class IV. Moreover, embolic complications occurred in only a small number of patients. In patients with obstructive thrombosis of LSMHVT, intravenous SK was effective and should be considered as first choice in patients in NYHA classes I-III, and as an acceptable alternative in those in NYHA class IV.

  12. Safety of antiobesity drugs.

    Science.gov (United States)

    Cheung, Bernard Man Yung; Cheung, Tommy Tsang; Samaranayake, Nithushi Rajitha

    2013-08-01

    Obesity is a major health problem worldwide. Although diet and physical activity are crucial in the management of obesity, the long-term success rate is low. Therefore antiobesity drugs are of great interest, especially when lifestyle modification has failed. As obesity is not an immediate life-threatening disease, these drugs are required to be safe. Antiobesity drugs that have been developed so far have limited efficacies and considerable adverse effects affecting tolerability and safety. Therefore, most antiobesity drugs have been withdrawn. Fenfluramine and dexfenfluramine were withdrawn because of the potential damage to heart valves. Sibutramine was associated with an increase in major adverse cardiovascular events in the Sibutramine Cardiovascular Outcomes (SCOUT) trial and it was withdrawn from the market in 2010. Rimonabant was withdrawn because of significant psychiatric adverse effects. Orlistat was approved in Europe and the United States for long-term treatment of obesity, but many patients cannot tolerate its gastrointestinal side effects. Phentermine and diethylpropion can only be used for less than 12 weeks because the long-term safety of these drugs is unknown. Ephedrine and caffeine are natural substances but the effects on weight reduction are modest. As a result there is a huge unmet need for effective and safe antiobesity drugs. Recently lorcaserin and topiramate plus phentermine have been approved for the treatment of obesity but long-term safety data are lacking.

  13. Inverse spin-valve effect in nanoscale Si-based spin-valve devices

    Science.gov (United States)

    Hiep, Duong Dinh; Tanaka, Masaaki; Hai, Pham Nam

    2017-12-01

    We investigated the spin-valve effect in nano-scale silicon (Si)-based spin-valve devices using a Fe/MgO/Ge spin injector/detector deposited on Si by molecular beam epitaxy. For a device with a 20 nm Si channel, we observed clear magnetoresistance up to 3% at low temperature when a magnetic field was applied in the film plane along the Si channel transport direction. A large spin-dependent output voltage of 20 mV was observed at a bias voltage of 0.9 V at 15 K, which is among the highest values in lateral spin-valve devices reported so far. Furthermore, we observed that the sign of the spin-valve effect is reversed at low temperatures, suggesting the possibility of a spin-blockade effect of defect states in the MgO/Ge tunneling barrier.

  14. Mitraclip Followed by Surgical Aortic Valve Replacement: Hybrid Techniques for Regurgitant Aortic and Mitral Valve Disease.

    Science.gov (United States)

    Eudailey, Kyle; Hamid, Nadira; Hahn, Rebecca T; Kodali, Susheel; Gray, William; George, Isaac

    2016-08-01

    With the advent of percutaneous valve interventions, the landscape for management of high-risk valve replacement and repair has changed dramatically. Transcatheter valve repair/replacement techniques can be used in conjunction with open surgery to facilitate a hybrid approach in patients with multivalve disease. We present a case of staged hybrid valve repair followed by surgical replacement for a high-risk patient with mitral regurgitation and aortic regurgitation. This case illustrates the effectiveness of the staged hybrid approach for high-risk patients with incomplete transcatheter options. We expect these techniques to play an increasingly larger role in the treatment algorithm for high-risk multivalve disease. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  15. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... distortion. (b) Exhalation valves shall be: (1) Protected against damage and external influence; and (2... or in the hose fitting near the facepiece of all Type A, AE, B, and BE supplied-air respirators. ...

  16. Transvalvular pressure gradients for different methods of mitral valve repair: only neochordoplasty achieves native valve gradients.

    Science.gov (United States)

    Jahren, Silje Ekroll; Hurni, Samuel; Heinisch, Paul Philipp; Winkler, Bernhard; Obrist, Dominik; Carrel, Thierry; Weber, Alberto

    2018-02-01

    Many surgical and interventional methods are available to restore patency for patients with degenerative severe mitral valve regurgitation. Leaflet resection and neochordoplasty, which both include ring annuloplasty, are the most frequently performed techniques for the repair of posterior mitral leaflet flail. It is unclear which technique results in the best haemodynamics. In this study, we investigated the effect of different mitral valve reconstruction techniques on mitral valve haemodynamics and diastolic transvalvular pressure gradient in an ex vivo porcine model. Eight porcine mitral valves were tested under pulsatile flow conditions in an in vitro pulsatile flow loop for haemodynamic quantification. Severe acute posterior mitral leaflet flail was created by resecting the posterior marginal chorda. The acute mitral valve regurgitation was corrected using 4 different repair techniques, in each valve, in a strictly successive order: (i) neochordoplasty with polytetrafluoroethylene sutures alone and (ii) with ring annuloplasty, (iii) edge-to-edge repair and (iv) triangular leaflet resection, both with ring annuloplasty. Valve haemodynamics were measured and quantified for all valve configurations (native, rupture and each surgical reconstruction). The results were analysed using a validated statistical linear mixed model, and the P-values were calculated using a 2-sided Wald test. All surgical reconstruction techniques were able to sufficiently correct the acute mitral valve regurgitation. Neochordoplasty without ring annuloplasty was the only reconstruction technique that resulted in haemodynamic properties similar to the native mitral valve (P-values from 0.071 to 0.901). The diastolic transvalvular gradient remained within the physiological range for all reconstructions but was significantly higher than in the native valve for neochordoplasty with ring annuloplasty (P < 0.000), edge-to-edge repair (P < 0.000) and leaflet resection (P < 0

  17. Effectiveness of rivaroxaban for thromboprophylaxis of prosthetic heart valves in a porcine heterotopic valve model.

    Science.gov (United States)

    Greiten, Lawrence E; McKellar, Stephen H; Rysavy, Joseph; Schaff, Hartzell V

    2014-05-01

    Warfarin is used to reduce the risk of stroke and thromboembolic complications in patients with mechanical heart valves. Yet, despite frequent blood testing, its poor pharmacokinetic and pharmacodynamic profiles often result in variable therapeutic levels. Rivaroxaban is a direct competitive factor Xa inhibitor that is taken orally. It inhibits the active site of factor Xa without the need for the cofactor antithrombin, and thus, its mechanism of action is differentiated from that of the fractionated heparins and indirect factor Xa inhibitors. No in vivo data exist regarding the effectiveness of rivaroxaban in preventing thromboembolic complications of mechanical heart valves. We tested the hypothesis that rivaroxaban is as effective as enoxaparin for thromboprophylaxis of mechanical valves that use a previously described heterotopic aortic valve porcine model. A modified bileaflet mechanical valved conduit that bypassed the native, ligated descending thoracic aorta was implanted into 30 swine. Postoperatively, the animals were randomly assigned to groups receiving no anticoagulation (n = 10), enoxaparin at 2 mg/kg subcutaneously twice daily (n = 10) or rivaroxaban at 2 mg/kg orally twice daily (n = 10). The amount of valve thrombus was measured on post-implantation day 30 as the primary end point. Quantitative evaluation of radiolabelled platelet deposition on the valve prostheses was done and embolic and haemorrhagic events were measured as secondary end points. Animals with no anticoagulation had a thrombus mean of 759.9 mg compared with 716.8 mg with enoxaparin treatment and 209.6 mg with rivaroxaban treatment (P = 0.05 for enoxaparin vs rivaroxaban). Similarly, the mean number of platelets deposited on the valve prosthesis was lower in the rivaroxaban group (6.13 × 10(9)) than in the enoxaparin group (3.03 × 10(10)) (P = 0.03). In this study, rivaroxaban was more effective than enoxaparin for short-term thromboprophylaxis of mechanical valve prosthetics in

  18. Predictors of permanent pacemaker implantation after transfemoral aortic valve implantation with the Lotus valve.

    Science.gov (United States)

    Keßler, Mirjam; Gonska, Birgid; Seeger, Julia; Rottbauer, Wolfgang; Wöhrle, Jochen

    2017-10-01

    Permanent pacemaker implantation (PPMI) after transcatheter aortic valve implantation is of high clinical relevance, but PPMI rates differ widely between valve types. Although the Lotus valve can be repositioned, reported rates for PPMI are high. The predictors of PPMI after Lotus valve implantation have not been defined yet. We analyzed the impact of preexisting conduction disturbances, depth of implantation, oversizing, and amount of calcification on PPMI in 216 patients with severe symptomatic aortic stenosis underdoing Lotus valve implantation. PPMI was required in 39.8% of patients. Patients with need for PPMI compared with patients without need for PPMI had more often the following criteria: male gender (P=.035); preprocedural right bundle-branch block (RBBB) (16.3% vs 0, P<.001); atrioventricular (AV) block first degree (26.7% vs 10.1%, P=.004); higher calcium volume of the left coronary cusp (63.1±87.5 mm(3) vs 42.8±49.3 mm(3), P=.05); and deeper valve implantation at right coronary (P=.011), noncoronary (P=.026), and left coronary (P=.012) position. Oversizing in relation to annulus and left ventricular outflow tract did not have an impact on need for PPMI. By multiple regression analysis, preprocedural AV block first degree (P=.005), RBBB (P<.001), and depth of implantation (P=.006) were independent risk factors for need of PPMI. In patients with severe aortic stenosis receiving transfemoral Lotus valve, preexisting AV block first degree, RBBB, and implantation depth are independent predictors of PPMI, highlighting the importance of careful valve positioning. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. 3D Printed Trileaflet Valve Conduits Using Biological Hydrogels and Human Valve Interstitial Cells

    OpenAIRE

    Duan, Bin; Kapetanovic, Edi; Hockaday, Laura A.; Butcher, Jonathan T.

    2013-01-01

    Tissue engineering has great potential to provide a functional de novo living valve replacement capable of integration with host tissue and growth. Among various valve conduit fabrication techniques, 3D bioprinting enables deposition of cells and hydrogels into 3D constructs with anatomical geometry and heterogeneous mechanical properties. Successful translation of this approach is however constrained by the dearth of printable and biocompatible hydrogel materials. Furthermore, it is not know...

  20. Characterization of Aortic Valve Closure Artifact During Outflow Tract Mapping: Correlation With Hemodynamics and Mechanical Valves.

    Science.gov (United States)

    Romero, Jorge; Ajijola, Olujimi; Shivkumar, Kalyanam; Tung, Roderick

    2017-06-01

    Premature ventricular contractions originating in the left ventricle outflow tract represent a significant subgroup of patients referred for catheter ablation. Mechanical artifacts from aortic valve leaflet motion may be observed during mapping, although the incidence and characteristics have not been reported. Twenty-eight consecutive patients with left ventricle outflow tract premature ventricular contraction were included. Electric signals recorded on the ablation catheter not coincident with atrial or ventricular depolarization were analyzed on the recording system. Correlation with invasive hemodynamic aortic pressure tracings was performed. Additionally, 4 patients with mechanical aortic valves, who underwent scar-related ventricular tachycardia ablation, were analyzed to correlate the timing of the observed artifacts with native aortic valves. Aortic valve artifact was observed while mapping within the coronary cusps in 11 patients (39%; 73% men; age, 41±25 years; left ventricular ejection fraction 49±16%) with high incidence from the left coronary cusp. This artifact was consistently observed with timing coincident with the terminal portion of the T wave. The average interval between the end of the T wave and the aortic valve artifact was 19±37 ms. The duration of the aortic valve artifact was 39±8 ms with amplitude of 0.12±0.07 mV (range, 0.06-0.36 mV). In patients referred for left ventricle outflow tract premature ventricular contraction ablation, an aortic valve closure artifact is observed in up to one third of cases during mapping within the aortic cusps. The timing of this artifact correlates with invasive hemodynamics and mechanical aortic valve artifacts. Recognition of this physiological phenomenon is useful when assigning near-field activation. © 2017 American Heart Association, Inc.

  1. The warm, rich sound of valve guitar amplifiers

    Science.gov (United States)

    Keeports, David

    2017-03-01

    Practical solid state diodes and transistors have made glass valve technology nearly obsolete. Nevertheless, valves survive largely because electric guitar players much prefer the sound of valve amplifiers to the sound of transistor amplifiers. This paper discusses the introductory-level physics behind that preference. Overdriving an amplifier adds harmonics to an input sound. While a moderately overdriven valve amplifier produces strong even harmonics that enhance a sound, an overdriven transistor amplifier creates strong odd harmonics that can cause dissonance. The functioning of a triode valve explains its creation of even and odd harmonics. Music production software enables the examination of both the wave shape and the harmonic content of amplified sounds.

  2. Three-dimensional analysis of partially open butterfly valve flows

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.; Kim, R.H. [Univ. of North Carolina, Charlotte, NC (United States). Dept. of Mechanical Engineering and Engineering Science

    1996-09-01

    A numerical simulation of butterfly valve flows is a useful technique to investigate the physical phenomena of the flow field. A three-dimensional numerical analysis was carried out on incompressible fluid flows in a butterfly valve by using FLUENT, which solves difference equations. Characteristics of the butterfly valve flows at different valve disk angles with a uniform incoming velocity were investigated. Comparisons of FLUENT results with other results, i.e., experimental results, were made to determine the accuracy of the employed method. Results of the three-dimensional analysis may be useful in the valve design.

  3. Cellular regulation of the structure and function of aortic valves

    Directory of Open Access Journals (Sweden)

    Ismail El-Hamamsy

    2010-01-01

    Full Text Available The aortic valve was long considered a passive structure that opens and closes in response to changes in transvalvular pressure. Recent evidence suggests that the aortic valve performs highly sophisticated functions as a result of its unique microscopic structure. These functions allow it to adapt to its hemodynamic and mechanical environment. Understanding the cellular and molecular mechanisms involved in normal valve physiology is essential to elucidate the mechanisms behind valve disease. We here review the structure and developmental biology of aortic valves; we examine the role of its cellular parts in regulating its function and describe potential pathophysiological and clinical implications.

  4. Valve Concepts for Microfluidic Cell Handling

    Directory of Open Access Journals (Sweden)

    M. Grabowski

    2010-01-01

    Full Text Available In this paper we present various pneumatically actuated microfluidic valves to enable user-defined fluid management within a microfluidic chip. To identify a feasible valve design, certain valve concepts are simulated in ANSYS to investigate the pressure dependent opening and closing characteristics of each design. The results are verified in a series of tests. Both the microfluidic layer and the pneumatic layer are realized by means of soft-lithographic techniques. In this way, a network of channels is fabricated in photoresist as a molding master. By casting these masters with PDMS (polydimethylsiloxane we get polymeric replicas containing the channel network. After a plasma-enhanced bonding process, the two layers are irreversibly bonded to each other. The bonding is tight for pressures up to 2 bar. The valves are integrated into a microfluidic cell handling system that is designed to manipulate cells in the presence of a liquid reagent (e.g. PEG – polyethylene glycol, for cell fusion. For this purpose a user-defined fluid management system is developed. The first test series with human cell lines show that the microfluidic chip is suitable for accumulating cells within a reaction chamber, where they can be flushed by a liquid medium.

  5. Diaphragms in air-operated valves

    Energy Technology Data Exchange (ETDEWEB)

    Groeger, J.E.

    1996-12-01

    The author will present current issues related to diaphgrams in air-operated valves. Altran Materials Engineering, Inc., often performs root-cause analyses for nuclear power plant owners. The author will discuss various analyses that have been performed or are currently underway.

  6. Ventriculopleural shunting with new technology valves.

    Science.gov (United States)

    Martínez-Lage, J F; Torres, J; Campillo, H; Sanchez-del-Rincón, I; Bueno, F; Zambudio, G; Poza, M

    2000-12-01

    Ventriculoperitoneal shunting constitutes the standard procedure for draining cerebrospinal fluid (CSF) in children with hydrocephalus. Ventriculoatrial and ventriculopleural shunting are alternative methods of CSF drainage, which have gained less acceptance. Ventriculopleural shunts are seldom used owing to justified fears of pneumothorax and symptomatic effusions of CSF. The addition of an antisiphon device to standard shunt systems seems to have prevented CSF pleural effusion. From 1988 to 1998, we treated each of six hydrocephalic children with a ventriculopleural shunt. In five cases we used new-technology valves designed to prevent the effects of siphoning with current differential pressure valves. Peritoneal adhesions, recent peritonitis, ascites, and obstruction of a previous ventriculoatrial shunt were the indications for pleural shunting. After a mean follow-up period of 2.5 years all shunts were functioning adequately. Only one patient showed transient symptoms of CSF overdrainage, which were corrected by up-grading the valve setting with the magnet. A late death was unrelated to the pleural shunting procedure. The use of valves of a new design designed to prevent overdrainage seems to account for the satisfactory outcomes observed in this series. We suggest that ventriculopleural shunting should be considered as the preferred alternative to peritoneal drainage in children with intra-abdominal adhesions or with a history of recent peritoneal infection.

  7. Suspension suture techniques in nasal valve surgery

    NARCIS (Netherlands)

    Page, Meile S.; Menger, Dirk J.

    2011-01-01

    Impaired nasal breathing or collapse of the lateral side wall of the nasal valve region during inspiration is a frequently encountered symptom. In general, this is caused by a cross-sectional area that is too small, a weak lateral side wall, or a combination of both. Over the years, many techniques

  8. Differential Pressure Helps Seal Ball Valve

    Science.gov (United States)

    Mangialardi, J. K.

    1985-01-01

    Leakage suppressed despite O-ring wear. New design eliminates leakage in vacuum selector valve on Space Shuttle waste-control subsystem. Applied to improve sealing in laboratory and industrial vacuum systems and other plumbing involving switching among lines with pressure differentials of order of 1 atmosphere (0.1 MPa).

  9. Autopsy after transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    van Kesteren, F; Wiegerinck, E M A; Rizzo, S

    2017-01-01

    Autopsy after transcatheter aortic valve implantation (TAVI) is a new field of interest in cardiovascular pathology. To identify the cause of death, it is important to be familiar with specific findings related to the time interval between the procedure and death. We aimed to provide an overview ...

  10. Potentially fatal tricuspid valve aspergilloma detected after ...

    African Journals Online (AJOL)

    Potentially fatal tricuspid valve aspergilloma detected after laparoscopic abdominal surgery. ... Aspergillus endocarditis is usually associated with high morbidity and mortality. ... The patient was successfully managed with emergency open-heart surgery and systemic antifungal agents in the postoperative period. Keywords: ...

  11. High readmission rate after heart valve surgery

    DEFF Research Database (Denmark)

    Sibilitz, K L; Berg, S K; Thygesen, Lau Caspar

    2015-01-01

    age (hazard ratio (95% CI): 1.3 (1.0-1.6)), male sex (1.2 (1.0-1.5)), mitral valve surgery (1.3 (1.0-1.6)), and infective endocarditis after surgery (1.8 (1.1-3.0), p: 0.01) predicted readmission, whereas higher age (2.3 (1.0-5.4)), higher comorbidity score (3.2 (1.8-6.0)), and infective endocarditis......BACKGROUND: After heart valve surgery, knowledge on long-term self-reported health status and readmission is lacking. Thus, the optimal strategy for out-patient management after surgery remains unclear. METHODS: Using a nationwide survey with linkage to Danish registers with one year follow-up, we...... included all adults 6-12 months after heart valve surgery irrespective of valve procedure, during Jan-June 2011 (n = 867). Participants completed a questionnaire regarding health-status (n = 742), and answers were compared with age- and sex-matched healthy controls. Readmission rates and mortality were...

  12. Minimally Invasive Mitral Valve Surgery III

    Science.gov (United States)

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

    2016-01-01

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

  13. The Neopuff's PEEP valve is flow sensitive.

    LENUS (Irish Health Repository)

    Hawkes, Colin Patrick

    2011-03-01

    The current recommendation in setting up the Neopuff is to use a gas flow of 5-15 L\\/min. We investigated if the sensitivity of the positive end expiratory pressure (PEEP) valve varies at different flow rates within this range.

  14. Antithrombotic therapy after bioprosthetic aortic valve implantation

    DEFF Research Database (Denmark)

    Rafiq, Sulman; Steinbrüchel, Daniel Andreas; Lilleør, Nikolaj Bang

    2017-01-01

    Background The optimal medical strategy for prevention of thromboembolic events after surgical bioprosthetic aortic valve replacement (BAVR) is still debated. The objective of this study was to compare warfarin therapy (target INR of 2.0 to 3.0) with aspirin 150 mg daily as antithrombotic therapy...

  15. Towards Performance Prognostics of a Launch Valve

    Science.gov (United States)

    2014-10-02

    Towards Performance Prognostics of a Launch Valve Glenn Shevach1, Mark Blair2, James Hing3, Larry Venetsky4, Everard Martin5, John Wheelock6...focuses on robotics and machine learning for ALRE & SE applications. Everard Martin is a Mechanical Engineer in the Steam Catapult Launcher In-Service

  16. Graphene spin valve: An angle sensor

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Zahir, E-mail: zahir.upc@gmail.com [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Hussain, Ghulam [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Siddique, Salma [Department of Bioscience & Biotechnology, Sejong University, Seoul 143-747 (Korea, Republic of); Iqbal, Muhammad Waqas [Department of Physics, Riphah Institute of Computing and Applied Sciences (RICAS), Riphah International University, Lahore (Pakistan)

    2017-06-15

    Graphene spin valves can be optimized for various spintronic applications by tuning the associated experimental parameters. In this work, we report the angle dependent magnetoresistance (MR) in graphene spin valve for different orientations of applied magnetic field (B). The switching points of spin valve signals show a clear shift towards higher B for each increasing angle of the applied field, thus sensing the response for respective orientation of the magnetic field. The angular variation of B shifts the switching points from ±95 G to ±925 G as the angle is varied from 0° to 90° at 300 K. The observed shifts in switching points become more pronounced (±165 G to ±1450 G) at 4.2 K for similar orientation. A monotonic increase in MR ratio is observed as the angle of magnetic field is varied in the vertical direction at 300 K and 4.2 K temperatures. This variation of B (from 0° to 90°) increases the magnitude of MR ratio from ∼0.08% to ∼0.14% at 300 K, while at 4.2 K it progresses to ∼0.39% from ∼0.14%. The sensitivity related to angular variation of such spin valve structure can be employed for angle sensing applications.

  17. Anterior mitral valve aneurysm: a rare sequelae of aortic valve endocarditis

    Directory of Open Access Journals (Sweden)

    Rajesh Janardhanan

    2016-05-01

    Full Text Available In intravenous drug abusers, infective endocarditis usually involves right-sided valves, with Staphylococcus aureus being the most common etiologic agent. We present a patient who is an intravenous drug abuser with left-sided (aortic valve endocarditis caused by Enterococcus faecalis who subsequently developed an anterior mitral valve aneurysm, which is an exceedingly rare complication. A systematic literature search was conducted which identified only five reported cases in the literature of mitral valve aneurysmal rupture in the setting of E. faecalis endocarditis. Real-time 3D-transesophageal echocardiography was critical in making an accurate diagnosis leading to timely intervention. Learning objectives: • Early recognition of a mitral valve aneurysm (MVA is important because it may rupture and produce catastrophic mitral regurgitation (MR in an already seriously ill patient requiring emergency surgery, or it may be overlooked at the time of aortic valve replacement (AVR. • Real-time 3D-transesophageal echocardiography (RT-3DTEE is much more advanced and accurate than transthoracic echocardiography for the diagnosis and management of MVA.

  18. Transcatheter mitral valve repair in osteogenesis imperfecta associated mitral valve regurgitation.

    Science.gov (United States)

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

    2014-08-01

    Osteogenesis imperfecta is associated with increased prevalence of significant mitral valve regurgitation. Surgical mitral valve repair and replacement are feasible but are associated with increased risk of bleeding and dehiscence of implanted valves may occur more frequently. The present case report describes the outcomes of transcatheter mitral valve repair in a patient with osteogenesis imperfecta. A 60 year-old patient with osteogenesis imperfecta and associated symptomatic moderate to severe mitral regurgitation underwent transthoracic echocardiography which showed a nondilated left ventricle with preserved systolic function and moderate to severe mitral regurgitation. On transoesophageal echocardiography the regurgitant jet originated between the anterolateral scallops of the anterior and posterior leaflets (A1-P1). Considering the comorbidities associated with osteogenesis imperfecta the patient was accepted for transcatheter mitral valve repair using the Mitraclip device (Abbott vascular, Menlo, CA). Under fluoroscopy and 3D transoesophageal echocardiography guidance, a Mitraclip device was implanted between the anterolateral and central scallops with significant reduction of mitral regurgitation. The postoperative evolution was uneventful. At one month follow-up, transthoracic echocardiography showed a stable position of the Mitraclip device with no mitral regurgitation. Transcatheter mitral valve repair is feasible and safe in patients with osteogenesis imperfecta and associated symptomatic significant mitral regurgitation. Copyright © 2014 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  19. Initial Experiences of Transcatheter Aortic Valve Implantation (TAVI in Iran with Midterm Follow up

    Directory of Open Access Journals (Sweden)

    Ali Mohammad Haji Zeinali

    2017-09-01

    Full Text Available Background: Surgical Aortic Valve Replacement (SAVR is the gold standard method for treatment of symptomatic severe senile Aortic Valve Stenosis (AS. For inoperable patients, due to severe co-morbidities, Transcatheter Aortic Valve Implantation (TAVI has been suggested as a new and safe alternative with significant follow up superiority to medical treatment; recently, it was suggested for patients at intermediate risk, as well. Since its introduction in 2002, TAVI has well developed in more than 40 countries. Objectives: We made an attempt to transfer this technology to Tehran University for the first time and then evaluated the feasibility and safety of this new technique with midterm closed clinical and echocardiographic follow up. Patients and Methods: Eight patients (5 males, with a mean age of 77 ± 6.7 years old underwent transfemoral TAVI from 2010, as the first sequential patients in Tehran University, by Balloon expandable bioprosthetic Edwards SAPIEN transcatheter heart valve, under general anesthesia in hybrid operation room. Results: There were 7 tricuspid valves and one bicuspid aortic valve (AV. All the patients had symptomatic severe senile valvular AS with severe co-morbidities so that the surgeons did not agree with open SAVR. Closed preprocedural, procedural, in hospital, one and 6 months clinical and echocardiographic assessments and follow up were done. Results: Procedural success rate was 100% with good implantation of the valve. A decrease in the AV mean gradient (MG from preprocedural mean AVMG 52.2 ± 19.7 mm Hg to 9.8 ± 3.7 mm Hg was observed in the 6 month follow up. One patient had procedural papillary muscle damage and moderate mitral regurgitation (MR, which needed hemodynamic support. No in hospital mortality or major complications were seen. In the follow up period, one patient had unexplained sudden death in sleep 3 weeks after the discharge. The other 7 patients had good 6 months of follow up with improvement of

  20. Hybrid textile heart valve prosthesis: preliminary in vitro evaluation.

    Science.gov (United States)

    Vaesken, Antoine; Pidancier, Christian; Chakfe, Nabil; Heim, Frederic

    2016-09-22

    Transcatheter aortic valve implantation (TAVI) is nowadays a popular alternative technique to surgical valve replacement for critical patients. Biological valve tissue has been used in these devices for over a decade now with over 100,000 implantations. However, material degradations due to crimping for catheter insertion purpose have been reported, and with only 6-year follow-up, no information is available about the long-term durability of biological tissue. Moreover, expensive biological tissue harvesting and chemical treatment procedures tend to promote the development of synthetic valve leaflet materials. Textile polyester (PET) material is characterized by outstanding folding and strength properties combined with proven biocompatibility and could therefore be considered as a candidate to replace biological valve leaflets in TAVI devices. Nevertheless, the material should be preferentially partly elastic in order to limit water hammer effects at valve closing time and prevent exaggerated stress from occurring into the stent and the valve. The purpose of the present work is to study in vitro the mechanical as well as the hydrodynamic behavior of a hybrid elastic textile valve device combining non-deformable PET yarn and elastic polyurethane (PU) yarn. The hybrid valve properties are compared with those of a non-elastic textile valve. Testing results show improved hydrodynamic properties with the elastic construction. However, under fatigue conditions, the interaction between PU and PET yarns tends to limit the valve durability.

  1. Reliability Evaluation of Concentric Butterfly Valve Using Statistical Hypothesis Test

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Mu Seong; Choi, Jong Sik; Choi, Byung Oh; Kim, Do Sik [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2015-12-15

    A butterfly valve is a type of flow-control device typically used to regulate a fluid flow. This paper presents an estimation of the shape parameter of the Weibull distribution, characteristic life, and B10 life for a concentric butterfly valve based on a statistical analysis of the reliability test data taken before and after the valve improvement. The difference in the shape and scale parameters between the existing and improved valves is reviewed using a statistical hypothesis test. The test results indicate that the shape parameter of the improved valve is similar to that of the existing valve, and that the scale parameter of the improved valve is found to have increased. These analysis results are particularly useful for a reliability qualification test and the determination of the service life cycles.

  2. Blood compatibility of the jellyfish valve without anticoagulant.

    Science.gov (United States)

    Imachi, K; Mabuchi, K; Chinzei, T; Abe, Y; Imanishi, K; Suzukawa, M; Yonezawa, T; Kouno, A; Ono, T; Nozawa, H

    1991-01-01

    The blood compatibility of the jellyfish valve was studied. Artificial heart (AH) blood pumps incorporating jellyfish valves were connected to 18 goats as total artificial hearts (TAHs) and pumped for 1 to 125 days without anticoagulant or antiplatelet drugs. No thrombus was formed on the valve membrane or around the valve seat. Scanning electron microscopy showed almost no platelet deposition or microfibrin clot formation on the valve membrane, including its central region; the spokes of the valve seat were also free from platelet and microfibrin clots. No calcification was observed during these tests, and plasma free hemoglobin was between 2 and 7 mg/dl. The jellyfish valve revealed good blood compatibility, even without anticoagulant use.

  3. Theoretical analysis of steady state operating forces in control valves

    Directory of Open Access Journals (Sweden)

    Basavaraj Hubballi

    2018-01-01

    Full Text Available The controlling components, such as valves are used to regulate controlled fluid power. It is not always possible to calculate valve forces accurately, and with some types of valves even the existence of certain types of forces cannot be predicted with certainty. In many cases, however, the analysis can be made fairly completely and accurately. The assumption of steady state conditions is valid for the valve alone, but transient effects in the rest of the system may be large. These effects are particularly important with regard to the instability of valves, where the system may react on the valve in such a way as to make it squeal or oscillate, sometimes with large amplitude. The origin of the steady state flow force understood from a brief qualitative explanation. The following paper will summarize much of what is known about valve forces in the spool type controlling element.

  4. Double orifice mitral valve: A case report

    Directory of Open Access Journals (Sweden)

    Musić Ljilja

    2016-01-01

    Full Text Available Introduction. Double orifice mitrol valve (DOMV is a very rare congenital heart defect. Case report. We reported 20-year-old male referred to our center due to evaluation of his cardiologic status. He was operated on shortly after birth for a tracheoesophageal fistula. Accidentally, echocardiography examination at the age of 4 years revealed double orifice mitral valve (DOMV without the presence of mitral regurgitation, as well as mitral stenosis, with normal dimensions of all cardiac chambers. The patient was asymptomatic, even more he was a kick boxer. His physical finding was normal. Electrocardiography showed regular sinus rhythm, incomplete right bundle branch block. Transthoracic echocardiography (TTE examination revealed the normal size of the left atrial, mitral leaflets were slightly more redundant. The left and right heart chambers, aorta, tricuspid valve and pulmonary artery valve were normal. During TTE examination on a short axis view two asymmetric mitral orifices were seen as a double mitral orifice through which we registered normal flow, without regurgitation and mitral stenosis. Transesophageal echocardiography (TEE examination from the transgastric view at the level of mitral valve, showed 2 single asymmetric mitral orifices separated by fibrous tissue, mitral leaflet with a separate insertion of hordes for each orifice. Conclusion. The presented patient with DOMV is the only one recognized in our country. The case is interesting because during 16-year a follow-up period there were no functional changes despite the fact that he performed very demanded sport activities. This is very important because there is no information in the literature about that.

  5. Feasibility and testing of lighweight, energy efficient, additive manufactured pneumatic control valve

    Energy Technology Data Exchange (ETDEWEB)

    Love, Lonnie J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mell, Ellen [Aerovalve, LLC, St. Louis, Mo (United States)

    2015-02-01

    AeroValve s innovative pneumatic valve technology recycles compressed air through the valve body with each cycle of the valve, and was reported to reduce compressed air requirements by an average of 25% 30%.This technology collaboration project between ORNL and Aerovalve confirms the energy efficiency of valve performance. Measuring air consumption per work completed, the AeroValve was as much as 85% better than the commercial Festo valve.

  6. New generation devices for transfemoral transcatheter aortic valve replacement are superior compared with last generation devices with respect to VARC-2 outcome.

    Science.gov (United States)

    Seeger, Julia; Gonska, Birgid; Rottbauer, Wolfgang; Wöhrle, Jochen

    2017-06-22

    New generation devices for transcatheter aortic valve replacement have been optimized to improve clinical outcome. We compared procedural, in-hospital, 30 days and 12 months outcome of the new generation repositionable Boston Lotus Valve and the balloon-expandable Edwards Sapien 3 valve with the last generation self-expandable Medtronic CoreValve and the balloon-expandable Edwards Sapien XT. Between 2010 and 2015 consecutive patients treated with the Medtronic CoreValve (N = 100), Edwards Sapien XT (N = 100), Edwards Sapien S3 (N = 100) and Boston Lotus device (N = 100) were enrolled. There was no moderate or severe AR with the new generation devices as compared with 11.5% with last generation devices (p < 0.01). None or trace aortic regurgitation was lowest with the Lotus valve. Pacemaker implantation due to II° or III° atrioventricular block was comparable for the self-expandable CoreValve (21%) and the mechanically deployed Lotus Valve (23%) and lower for the Sapien 3 (15%) and XT valve (8%; p < 0.01). Early safety endpoint at 30 days (21 vs. 9%, p < 0.01), major vascular complications (12 vs. 2.5%, p < 0.01), all-cause mortality (9.5 vs. 2%, p < 0.01) and rate of disabling and non-disabling stroke (7.5 vs. 3.5%, p < 0.01) were significantly lower with the new generation devices. In multivariate analyses, valve type was an independent predictor for 30 days early safety endpoint and 12 months all-cause mortality. TAVR with the new generation Edwards Sapien 3 and Boston Lotus valves was associated with no moderate and severe aortic regurgitation, significantly lower major vascular complications and a significant improvement in 30 days and 12 months outcome.Clinicaltrials.gov NCT02162069.

  7. Effect of experience on results of transcatheter aortic valve implantation using a Medtronic CoreValve System.

    Science.gov (United States)

    Nuis, Rutger-Jan; van Mieghem, Nicolas M; van der Boon, Robert M; van Geuns, Robert-Jan; Schultz, Carl J; Oei, Frans B; Galema, Tjebbe W; Raap, Goris Bol; Koudstaal, Peter J; Geleijnse, Marcel L; Kappetein, Arie Pieter; Serruys, Patrick W; de Jaegere, Peter P

    2011-06-15

    Outcome after transcatheter aortic valve implantation (TAVI) depends on the patient risk profile, operator experience, progress in technology, and technique. We sought to compare the results of TAVI during the initiation phase and after certification to perform TAVI with the Medtronic CoreValve System without proctoring. A total of 165 consecutive patients was categorized into a first cohort of 33 patients treated before certification (November 2005 to December 2007) and a second cohort of 132 patients treated after certification (January 2008 to October 2010). The study end points were selected and defined according to the Valve Academic Research Consortium recommendations. Compared to cohort 2, the patients in cohort 1 more frequently had New York Heart Association class III-IV (100% vs 71%, p <0.001), hypertension (67% vs 39%, p = 0.004), and aortic regurgitation grade III-IV (46% vs 22%, p = 0.006) before TAVI. Over time, the patients in cohort 2 more frequently underwent a truly percutaneous approach (98% vs 82%, p = 0.002) without circulatory support (96% vs 67%, p <0.001) but with more concomitant percutaneous coronary intervention (11% vs 0%, p = 0.042) than the patients in cohort 1. They also more often received a 29-mm prosthesis (72% vs 24%, p <0.001), required less postimplantation balloon dilation (10% vs 27%, p = 0.008), and had less aortic regurgitation grade III-IV after TAVI (12% vs 30%, p = 0.010). The clinical outcome showed a nonsignificant reduction in the combined safety end point (30% to 17%) but a significant reduction in cerebrovascular events (21% to 7%, p = 0.020) and life-threatening bleeding (15% to 5%, p = 0.044) in cohort 2. However, the reduction in overall bleeding and vascular complications (25% and 14%, respectively) was not significant. In conclusion, TAVI became significantly less complex and was associated with better results over time but remained associated with a high frequency of periprocedural major cardiovascular

  8. How Heart Valves Evolve to Adapt to an Extreme-Pressure System: Morphologic and Biomechanical Properties of Giraffe Heart Valves.

    Science.gov (United States)

    Amstrup Funder, Jonas; Christian Danielsen, Carl; Baandrup, Ulrik; Martin Bibby, Bo; Carl Andelius, Ted; Toft Brøndum, Emil; Wang, Tobias; Michael Hasenkam, J

    2017-01-01

    Heart valves which exist naturally in an extreme-pressure system must have evolved in a way to resist the stresses of high pressure. Giraffes are interesting as they naturally have a blood pressure twice that of humans. Thus, knowledge regarding giraffe heart valves may aid in developing techniques to design improved pressure-resistant biological heart valves. Heart valves from 12 giraffes and 10 calves were explanted and subjected to either biomechanical or morphological examinations. Strips from the heart valves were subjected to cyclic loading tests, followed by failure tests. Thickness measurements and analyses of elastin and collagen content were also made. Valve specimens were stained with hematoxylin and eosin, elastic van Gieson stain, Masson's trichrome and Fraser-Lendrum stain, as well as immunohistochemical reactions for morphological examinations. The aortic valve was shown to be 70% (95% CI 42-103%) stronger in the giraffe than in its bovine counterpart (p giraffe aortic valve was found to be significantly stiffer than the bovine aortic valve (p giraffes contained significantly more collagen than those of calves. The elastin contents of the pulmonary valves (2.5%) and aortic valves (1.5%) were also higher in giraffes. The greater strength of the giraffe aortic valve is most likely due to a compact collagen construction. Both, collagen and elastin contents were higher in giraffes than in calves, which would make giraffe valves more resistant to the high-pressure forces. However, collagen also stiffens and thickens the valves. The mitral leaflets showed similar (but mostly insignificant) trends in strength, stiffness, and collagen content.

  9. Fusion of valve cushions as a key factor in the formation of congenital bicuspid aortic valves in Syrian hamsters.

    Science.gov (United States)

    Sans-Coma, V; Fernández, B; Durán, A C; Thiene, G; Arqué, J M; Muñoz-Chápuli, R; Cardo, M

    1996-04-01

    Bicuspid aortic valve is the most frequent congenital cardiac malformation in humans. However, the morphogenesis of the defect is still unknown. Previous work showed that, in the Syrian hamster, congenital bicuspid aortic valves with the aortic sinuses arranged in ventrodorsal orientation are expressions of a trait the variation of which takes the form of a continuous phenotypic spectrum, ranging from a tricuspid aortic valve with no fusion of the ventral commissure to a bicuspid aortic valve devoid of any raphe. The present study was designed to elucidate the mechanism involved in the formation of bicuspid aortic valves in Syrian hamsters as a possible starting point for further investigation of this process in humans. The sample examined consisted of 80 embryos, aged between 10 days, 16 hours and 13 days, 1 hour postcoitum. Most (n = 59) of the embryos belonged to a laboratory-inbred family of Syrian hamsters with a high incidence of bicuspid aortic valves. The study was carried out using scanning electron microscopy and histological techniques for light microscopy. Twenty-three embryos showed a still undivided conotruncus. In all of these cases there were six mesenchymal semilunar valve primordia protruding into the lumen of the conotruncus. In a further 29 embryos, the conotruncus had just divided into the aortic and pulmonary channels; the embryos were at the beginning of the valvulogenesis. In 13 of these 29 embryos there were three well-defined aortic valve cushions, right, left, and dorsal, whereas in the other 16, the right and left valve cushions were more or less fused toward the lumen of the aorta; when they were completely fused, only two aortic valve cushions, a ventral and a dorsal, could be identified. In the remaining 28 embryos, the aortic valve cushions showed a marked degree of excavation. In 23 of these cases, the valve exhibited a basically tricuspid architecture, whereas it was unequivocally bicuspid in the other five. All variants of the

  10. St Jude Epic heart valve bioprostheses versus native human and porcine aortic valves - comparison of mechanical properties.

    Science.gov (United States)

    Kalejs, Martins; Stradins, Peteris; Lacis, Romans; Ozolanta, Iveta; Pavars, Janis; Kasyanov, Vladimir

    2009-05-01

    The major problem with heart valve bioprostheses made from chemically treated porcine aortic valves is their limited longevity caused by gradual deterioration, which has a causal link with valve tissue mechanical properties. To our best knowledge, there are no published studies on the mechanical properties of modern, commercially available bioprostheses comparing them to native human valves. The objective of this study is to determine the mechanical properties of St Jude Epic bioprostheses and to compare them with native human and porcine aortic valves. Leaflets from eight porcine aortic valves and six Epic bioprostheses were analyzed using uni-axial tensile tests in radial and circumferential directions. Mechanical properties of human valves have been previously published by our group. Results are represented as mean values+/-S.D. Circumferential direction. Modulus of elasticity of Epic bioprostheses in circumferential direction at the level of stress 1.0 MPa is 101.99+/-58.24 MPa, 42.3+/-4.96 MPa for native porcine and 15.34+/-3.84 MPa for human aortic valves. Ultimate stress is highest for Epic bioprostheses 5.77+/-1.94 MPa, human valves have ultimate stress of 1.74+/-0.29 MPa and porcine 1.58+/-0.26 MPa. Ultimate strain in circumferential direction is highest for human valves 18.35+/-7.61% followed by 7.26+/-0.69% for porcine valves and 5.95+/-1.54% for Epic bioprostheses. Radial direction. Modulus of elasticity in radial direction is 9.18+/-1.81 MPa for Epic bioprostheses, 5.33+/-0.61 MPa for native porcine, and 1.98+/-0.15 MPa for human aortic valve leaflets. In the radial direction ultimate stress is highest for Epic bioprostheses 0.7+/-0.21 MPa followed by native porcine valves 0.55+/-0.11 MPa and 0.32+/-0.04 MPa for human valves. For human valves ultimate strain is 23.92+/-4.87%, for native porcine valves 8.57+/-0.8% and 7.92+/-1.74% for Epic bioprostheses. Epic bioprostheses have non-linear stress-strain behavior similar to native valve tissue, but they

  11. Cardiac energetics analysis after aortic valve replacement with 16-mm ATS mechanical valve.

    Science.gov (United States)

    Ushijima, Tomoki; Tanoue, Yoshihisa; Uchida, Takayuki; Matsuyama, Sho; Matsumoto, Takashi; Tominaga, Ryuji

    2014-09-01

    The 16-mm ATS mechanical valve is one of the smallest prosthetic valves used for aortic valve replacement (AVR) in patients with a very small aortic annulus, and its clinical outcomes are reportedly satisfactory. Here, we analyzed the left ventricular (LV) performance after AVR with the 16-mm ATS mechanical valve, based on the concept of cardiac energetics analysis. Eleven patients who underwent AVR with the 16-mm ATS mechanical valve were enrolled in this study. All underwent echocardiographic examination at three time points: before AVR, approximately 1 month after AVR, and approximately 1 year after AVR. LV contractility (end-systolic elastance [Ees]), afterload (effective arterial elastance [Ea]), and efficiency (ventriculoarterial coupling [Ea/Ees] and the stroke work to pressure-volume area ratio [SW/PVA]) were noninvasively measured by echocardiographic data and blood pressure measurement. Ees transiently decreased after AVR and then recovered to the pre-AVR level at the one-year follow-up. Ea significantly decreased in a stepwise manner. Consequently, Ea/Ees and SW/PVA were also significantly improved at the one-year follow-up compared with those before AVR. The midterm LV performance after AVR with the 16-mm ATS mechanical valve was satisfactory. AVR with the 16-mm ATS mechanical valve is validated as an effective treatment for patients with a very small aortic annulus. The cardiac energetics variables, coupling with the conventional hemodynamic variables, can contribute to a better understanding of the patients' clinical conditions, and those may serve as promising indices of the cardiac function.

  12. Combined aortic root replacement and mitral valve surgery: The quest to preserve both valves.

    Science.gov (United States)

    Javadikasgari, Hoda; Roselli, Eric E; Aftab, Muhammad; Suri, Rakesh M; Desai, Milind Y; Khosravi, Mitra; Cikach, Frank; Isabella, Monica; Idrees, Jay J; Raza, Sajjad; Tappuni, Bassman; Griffin, Brian P; Svensson, Lars G; Gillinov, A Marc

    2017-05-01

    Coexisting aortic root and mitral valve pathology is increasingly recognized among patients undergoing surgery. We characterized the pathology and surgical outcomes of patients with combined aortic root and mitral disease. From 1987 to 2016, 118 patients (age 52.40 ± 17.71 years) underwent concomitant aortic root and mitral procedures (excluding aortic stenosis, endocarditis, and reoperations). Aortic root pathologies included degenerative aneurysm (94%) and aortic dissection (6%). The aortic valve was bicuspid in 15% of patients and had normally functioning tricuspid leaflets in 23% of patients. Marfan syndrome was present in 34 patients (29%). Degenerative mitral disease predominated (78%). Mitral procedures were repair (86%) and replacement (14%), and root procedures were valve-preserving root reimplantation (36%), Bentall procedure (47%), and homograft root replacement (17%). In the last 10 years, the combination of valve-preserving root reimplantation and mitral repair has increased to 50%. Kaplan-Meier and competing risk analyses were used to estimate survival and reoperation. There were 2 (1.7%) operative deaths with survival of 79% and 71% at 10 and 15 years, respectively, and reoperation rates of 4.7% and 12% after 5 and 10 years, respectively. There were no operative deaths in patients with combined valve-preserving root reimplantation and mitral repair, with survival of 89% and reoperation rate of 7.8% at 10 years. Among patients with Bentall/homograft and mitral operation, survival was 73% and reoperation was 9.8% at 10 years. In patients with aortic root and mitral pathology, combined surgical risk is low and valve durability is high. When possible, valve-preserving root reimplantation and mitral repair should be considered to avoid prosthesis degeneration, anticoagulation, and lifestyle limitations. Copyright © 2017. Published by Elsevier Inc.

  13. Clinical outcomes in 1731 patients undergoing mitral valve surgery for rheumatic valve disease.

    Science.gov (United States)

    Kim, Wan Kee; Kim, Ho Jin; Kim, Joon Bum; Jung, Sung-Ho; Choo, Suk Jung; Chung, Cheol Hyun; Lee, Jae Won

    2017-11-16

    Unlike degenerative mitral valve (MV) disease, the advantages of valve repair procedure over replacement have been debated in rheumatic MV disease. This study aims to evaluate the impact of procedural types on long-term outcomes through analyses on a large data set from an endemic area of rheumatic disease. We evaluated 1731 consecutive patients (52.3±12.5 years; 1190 women) undergoing MV surgery for rheumatic MV disease between 1997 and 2015. Long-term survival and valve-related outcomes were compared between repair and replacement procedures. To adjust for selection bias, propensity score analyses were performed. Patients undergoing repair were younger and had more predominant mitral regurgitation than mechanical and bioprosthetic replacement groups (61.6% vs 15.6% vs 24.4%; Pvalve-related complications. Propensity score matching yielded 188 pairs of repair and replacement patients that were well balanced for baseline covariates. In the matched cohort, there was no significant difference in the mortality risk between the repair and replacement groups (HR, 1.24; 95% CI 0.62 to 2.48). The risk of composite valve-related complications, however, was significantly lower in repair group (HR, 0.57; 95% CI 0.33 to 0.99) principally derived by a lower risk of haemorrhagic events (HR, 0.23; 95% CI 0.07 to 0.70). The incidence of reoperation was not significantly different between groups in the matched cohort (HR, 1.62; 95% CI 0.49 to 5.28). Valve repair in well-selected patients with severe rheumatic MV disease led to comparable survival, but superior valve-related outcomes compared with valve replacement surgery. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  14. A prospective randomized evaluation of the TriGuard (TM) HDH embolic DEFLECTion device during transcatheter aortic valve implantation : results fromthe DEFLECT III trial

    NARCIS (Netherlands)

    Lansky, Alexandra J.; Schofer, Joachim; Tchetche, Didier; Stella, Pieter; Pietras, Cody G.; Parise, Helen; Abrams, Kevin; Forrest, John K.; Cleman, Michael; Reinoehl, Jochen; Cuisset, Thomas; Blackman, Daniel; Bolotin, Gil; Spitzer, Stefan; Kappert, Utz; Gilard, Martine; Modine, Thomas; Hildick-Smith, David; Haude, Michael; Margolis, Pauliina; Brickman, Adam M.; Voros, Szilard; Baumbach, Andreas

    2015-01-01

    Aims To evaluate the safety, efficacy, and performance of the TriGuard (TM) HDH Embolic Deflection Device (TriGuard) compared with no cerebral protection in patients undergoing transcatheter aortic valve implantation (TAVI). Methods and results From February 2014 to March 2015, 85 subjects

  15. THE EFFECTS OF MAINTENANCE ACTIONS ON THE PFDavg OF SPRING OPERATED PRESSURE RELIEF VALVES

    Energy Technology Data Exchange (ETDEWEB)

    Harris, S.; Gross, R.

    2014-04-01

    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated pressure relief valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

  16. Early Outcomes of Sutureless Aortic Valves

    Directory of Open Access Journals (Sweden)

    Muhammet Onur Hanedan

    2016-06-01

    Full Text Available Background: In elderly high-risk surgical patients, sutureless aortic valve replacement (AVR should be an alternative to standard AVR. The potential advantages of sutureless aortic prostheses include reducing cross-clamping and cardiopulmonary bypass (CPB time and facilitating minimally invasive surgery and complex cardiac interventions, while maintaining satisfactory hemodynamic outcomes and low rates of paravalvular leakage. The current study reports our single-center experience regarding the early outcomes of sutureless aortic valve implantation. Methods: Between October 2012 and June 2015, 65 patients scheduled for surgical valve replacement with symptomatic aortic valve disease and New York Heart Association function of class II or higher were included to this study. Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy and Edwards Intuity (Edwards Lifesciences, Irvine, CA, USA valves were used. Results: The mean age of the patients was 71.15±8.60 years. Forty-four patients (67.7% were female. The average preoperative left ventricular ejection fraction was 56.9±9.93. The CPB time was 96.51±41.27 minutes and the cross-clamping time was 60.85±27.08 minutes. The intubation time was 8.95±4.19 hours, and the intensive care unit and hospital stays were 2.89±1.42 days and 7.86±1.42 days, respectively. The mean quantity of drainage from chest tubes was 407.69±149.28 mL. The hospital mortality rate was 3.1%. A total of five patients (7.69% died during follow-up. The mean follow-up time was 687.24±24.76 days. The one-year survival rate was over 90%. Conclusion: In the last few years, several models of valvular sutureless bioprostheses have been developed. The present study evaluating the single-center early outcomes of sutureless aortic valve implantation presents the results of an innovative surgical technique, finding that it resulted in appropriate hemodynamic conditions with acceptable ischemic time.

  17. Serotonin Mechanisms in Heart Valve Disease I

    Science.gov (United States)

    Jian, Bo; Xu, Jie; Connolly, Jeanne; Savani, Rashmin C.; Narula, Navneet; Liang, Bruce; Levy, Robert J.

    2002-01-01

    Clinical disorders associated with increased serotonin [5-hydroxytryptamine (5-HT)] levels, such as carcinoid syndrome, and the use of serotonin agonists, such as fenfluoramine have been associated with a valvulopathy characterized by hyperplastic valvular and endocardial lesions with increased extracellular matrix. Furthermore, 5-HT has been demonstrated to up-regulate transforming growth factor (TGF)-β in mesangial cells via G-protein signal transduction. We investigated the hypothesis that increased exposure of heart valve interstitial cells to 5-HT may result in increased TGF-β1 expression and activity because of serotonin receptor-mediated signal transduction with activation of Gαq, and subsequently up-regulation of phospholipase C. Thus, in the present study we performed a clinical-pathological investigation of retrieved carcinoid and normal valve cusps using immunohistochemical techniques to detect the presence of TGF-β1 and other proteins associated with TGF-β expression, including TGF-β receptors I and II, latent TGF-β-associated peptide (LAP), and α-smooth muscle actin. Carcinoid valve cusps demonstrated the unusual finding of widespread smooth muscle actin involving the interstitial cells in the periphery of carcinoid nodules; these same cells were also positive for LAP. Normal valve cusps were only focally positive for smooth muscle actin and LAP. In sheep aortic valve interstitial cell cultures 5-HT induced TGF-β1 mRNA production and increased TGF-β1 activity. 5-HT also increased collagen biosynthesis at the dosages studied. Furthermore, TGF-β1 added to SAVIC cultures increased the production of sulfated glycan and hyaluronic acid. In addition, overexpression of Gαq using an adenoviral expression vector for a constitutively active Gαq mutant (Q209L-Gαq) resulted in increased phospholipase C activity as well as up-regulation of TGF-β expression and activity. These results strongly support the view that G-protein-related signal

  18. 30 CFR 75.1904 - Underground diesel fuel tanks and safety cans.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground diesel fuel tanks and safety cans... § 75.1904 Underground diesel fuel tanks and safety cans. (a) Diesel fuel tanks used underground shall... valves located as close as practicable to the tank shell on each connection through which liquid can...

  19. Morphological aspects of atrioventricular valves in the ostrich (Struthio camelus

    Directory of Open Access Journals (Sweden)

    Marco A. Pereira-Sampaio

    2013-11-01

    Full Text Available Heart anatomy in the ostrich has been reported, but there are few information on the histological features of the atrioventricular valves. Hearts of young ostriches were fixed in 10% formaldehyde for 24 h and dissected to characterize their macroscopic anatomy. Samples of valves were harvested and stained with Mallory’s trichrome, Gomori’s trichrome, and Picro-Sirius red, for later analysis. The right atrioventricular valve consists of a muscle flap with two fixations. The left atrioventricular valve consists of two layers of endocardium with a layer of connective tissue between them. The free border of the tricuspid valve supports a varying number of chordae tendineae. One of the cusps is attached to the septum, while the other two cusps are attached to the opposite wall. The aortic valve, as well as the pulmonary trunk valve, consists of three cusps. The right atrioventricular valve showed up only as a muscle flap of myocardium coated with a thin layer of dense connective tissue, with two fixations. In the connective tissue, we find a predominance of type I collagen fibers and a lesser amount of type III, with a small presence of elastic fibers. The presence of Purkinje fibers were also usual in the valvular subendocardium, suggesting that they directly participate in the transmission of nervous stimulation to the muscle fibers within the valves. The left atrioventricular valve consisted of 3 cusps, a dorsal, a left, and a right.

  20. Inhibitory role of Notch1 in calcific aortic valve disease.

    Directory of Open Access Journals (Sweden)

    Asha Acharya

    Full Text Available Aortic valve calcification is the most common form of valvular heart disease, but the mechanisms of calcific aortic valve disease (CAVD are unknown. NOTCH1 mutations are associated with aortic valve malformations and adult-onset calcification in families with inherited disease. The Notch signaling pathway is critical for multiple cell differentiation processes, but its role in the development of CAVD is not well understood. The aim of this study was to investigate the molecular changes that occur with inhibition of Notch signaling in the aortic valve. Notch signaling pathway members are expressed in adult aortic valve cusps, and examination of diseased human aortic valves revealed decreased expression of NOTCH1 in areas of calcium deposition. To identify downstream mediators of Notch1, we examined gene expression changes that occur with chemical inhibition of Notch signaling in rat aortic valve interstitial cells (AVICs. We found significant downregulation of Sox9 along with several cartilage-specific genes that were direct targets of the transcription factor, Sox9. Loss of Sox9 expression has been published to be associated with aortic valve calcification. Utilizing an in vitro porcine aortic valve calcification model system, inhibition of Notch activity resulted in accelerated calcification while stimulation of Notch signaling attenuated the calcific process. Finally, the addition of Sox9 was able to prevent the calcification of porcine AVICs that occurs with Notch inhibition. In conclusion, loss of Notch signaling contributes to aortic valve calcification via a Sox9-dependent mechanism.