46 CFR 38.10-15 - Safety relief valves-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Safety relief valves-TB/ALL. 38.10-15 Section 38.10-15..., Fittings, and Accessory Equipment § 38.10-15 Safety relief valves—TB/ALL. (a) Each tank shall be fitted with or (subject to approval by the Commandant) connected to one or more safety relief valves designed...

Subsurface safety valves: safety asset or safety liability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Busch, J.M.; Llewelyn, D.C.G.; Policky, B.J.

1983-10-01

This paper summarizes the methods used to compare the risk of a blowout for a well completed with a subsurface safety valve (SSSV) vs. a completion without an SSSV. These methods, which could be applied to any field, include a combination of SSSV reliability and conventional risk analyses. The Kuparuk River Unit Working Interest Owners recently formed a group to examine the risks associated with installing and maintaining SSSV's in the Kuparuk field. The group was charged with answering the question: ''Assuming Kuparuk field operating conditions, are SSSV's a safety asset, or do numerous operating and maintenance procedures make themmore » a safety liability.'' The results indicate that for the Kuparuk River Unit, an SSSV becomes a safety liability when the mean time between SSSV failures is less than one year. Since current SSSV mean time to failure (MTTF) at Kuparuk is approximately 1000 days, they are considered a safety asset.« less

46 CFR 58.16-15 - Valves and safety relief devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND... and safety relief devices. (a) Each cylinder shall have a manually operated screw-down shutoff valve...

46 CFR 58.16-15 - Valves and safety relief devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND... and safety relief devices. (a) Each cylinder shall have a manually operated screw-down shutoff valve...

46 CFR 58.16-15 - Valves and safety relief devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND... and safety relief devices. (a) Each cylinder shall have a manually operated screw-down shutoff valve...

46 CFR 58.16-15 - Valves and safety relief devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND... and safety relief devices. (a) Each cylinder shall have a manually operated screw-down shutoff valve...

Study on high reliability safety valve for railway vehicle

NASA Astrophysics Data System (ADS)

Zhang, Xuan; Chen, Ruikun; Zhang, Shixi; Xu, BuDu

2017-09-01

Now, the realization of most of the functions of the railway vehicles rely on compressed air, so the demand for compressed air is growing higher and higher. This safety valve is a protection device for pressure limitation and pressure relief in an air supply system of railway vehicles. I am going to introduce the structure, operating principle, research and development process of the safety valve designed by our company in this document.

Innovative safety valve selection techniques and data.

PubMed

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.

46 CFR 58.16-15 - Valves and safety relief devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Liquefied Petroleum Gases for Cooking and Heating § 58.16-15 Valves...

Water hammer caused by closure of turbine safety spherical valves

NASA Astrophysics Data System (ADS)

Karadžić, U.; Bergant, A.; Vukoslavčević, P.

2010-08-01

This paper investigates water hammer effects caused by closure of spherical valves against the discharge. During the first phase of modernisation of Perućica high-head hydropower plant (HPP), Montenegro, safety spherical valves (inlet turbine valves) have been refurbished on the first two Pelton turbine units. The valve closure is controlled by the valve actuator (hydraulic servomotor). Because the torque acting on the valve body is dependent on flow conditions the valve closing time may vary significantly for different flow velocities (passive valve). For the passive valve the torques acting on the valve body should be considered in the valve model. The valve closing time results from numerical simulation. On the contrary, for the active valve the valve closing time is assumed prior to simulation. The spherical valve boundary condition is incorporated into the method of characteristics (MOC) algorithm. The staggered (diamond) grid in applying the MOC is used in this paper. The passive valve boundary condition is described by the water hammer equations, the valve equation that relates discharge to pressure head drop and the dynamic equation of the valve body motion (torque equation). The active valve boundary condition is described by the first two equations, respectively. Standard quasi-steady friction model is used for estimating friction losses in plant's tunnel and penstocks. Numerical results using both the active and the passive spherical valve models are compared with results of measurements. It has been found that the influence of flow conditions on the spherical valve closing time is minor for the cases considered. Computed and measured results agree reasonably well.

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

PubMed

Fiorina, Claudia; Maffeo, Diego; Curello, Salvatore; Lipartiti, Felicia; Chizzola, Giuliano; D'Aloia, Antonio; Adamo, Marianna; Mastropierro, Rosy; Gavazzi, Emanuele; Ciccarese, Camilla; Chiari, Ermanna; Ettori, Federica

2014-06-01

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. 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. 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. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

49 CFR 179.100-19 - Tests of safety relief valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Tests of safety relief valves. 179.100-19 Section... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120...

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 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...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 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...

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 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...

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

Code of Federal Regulations, 2010 CFR

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...

77 FR 28669 - Pipeline Safety: Information Collection Activities, Excess Flow Valve Census

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-15

... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No. PHMSA-2012-0086] Pipeline Safety: Information Collection Activities, Excess Flow Valve Census AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA), DOT. ACTION: Notice and request for...

46 CFR 56.50-25 - Safety and relief valve escape piping.

Code of Federal Regulations, 2010 CFR

2010-10-01

... supported and installed so that no stress is transmitted to the safety valve body. (c) Safety or relief... or to a remote position to minimize the hazardous effect of the escaping steam. (d) The effect of the...

49 CFR 179.100-19 - Tests of safety relief valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Tests of safety relief valves. 179.100-19 Section... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-19...

49 CFR 179.100-19 - Tests of safety relief valves.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Tests of safety relief valves. 179.100-19 Section... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-19...

49 CFR 179.100-19 - Tests of safety relief valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Tests of safety relief valves. 179.100-19 Section... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-19...

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

Code of Federal Regulations, 2014 CFR

2014-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System...

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

Code of Federal Regulations, 2012 CFR

2012-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System...

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

Code of Federal Regulations, 2013 CFR

2013-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System...

46 CFR 98.25-60 - Safety relief valves.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

46 CFR 98.25-60 - Safety relief valves.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

46 CFR 98.25-60 - Safety relief valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

46 CFR 98.25-60 - Safety relief valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

46 CFR 98.25-60 - Safety relief valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk...

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

Code of Federal Regulations, 2010 CFR

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...

46 CFR 61.05-20 - Boiler safety valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Boiler safety valves. 61.05-20 Section 61.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND..., superheater, or reheater of a boiler shall be tested at the interval specified by table 61.05-10. [CGD 95-028...

46 CFR 61.05-20 - Boiler safety valves.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Boiler safety valves. 61.05-20 Section 61.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND..., superheater, or reheater of a boiler shall be tested at the interval specified by table 61.05-10. [CGD 95-028...

46 CFR 61.05-20 - Boiler safety valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Boiler safety valves. 61.05-20 Section 61.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND..., superheater, or reheater of a boiler shall be tested at the interval specified by table 61.05-10. [CGD 95-028...

46 CFR 61.05-20 - Boiler safety valves.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Boiler safety valves. 61.05-20 Section 61.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND..., superheater, or reheater of a boiler shall be tested at the interval specified by table 61.05-10. [CGD 95-028...

46 CFR 61.05-20 - Boiler safety valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Boiler safety valves. 61.05-20 Section 61.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND..., superheater, or reheater of a boiler shall be tested at the interval specified by table 61.05-10. [CGD 95-028...

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Safety valve requirements for steam boilers (modifies HG-400 and HG-401). 53.05-1 Section 53.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Safety valve requirements for steam boilers (modifies HG-400 and HG-401). 53.05-1 Section 53.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG...

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Safety valve requirements for steam boilers (modifies HG-400 and HG-401). 53.05-1 Section 53.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG...

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Safety valve requirements for steam boilers (modifies HG-400 and HG-401). 53.05-1 Section 53.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG...

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

Code of Federal Regulations, 2010 CFR

2010-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.445 What...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop...

Bioprosthetic Valve Fracture to Facilitate Transcatheter Valve-in-Valve Implantation.

PubMed

Allen, Keith B; Chhatriwalla, Adnan K; Cohen, David J; Saxon, John T; Aggarwal, Sanjeev; Hart, Anthony; Baron, Suzanne; Davis, J Russell; Pak, Alex F; Dvir, Danny; Borkon, A Michael

2017-11-01

Valve-in-valve transcatheter aortic valve replacement is less effective in small surgical bioprostheses. We evaluated the feasibility of bioprosthetic valve fracture with a high-pressure balloon to facilitate valve-in-valve transcatheter aortic valve replacement. In vitro bench testing on aortic tissue valves was performed on 19-mm and 21-mm Mitroflow (Sorin, Milan, Italy), Magna and Magna Ease (Edwards Lifesciences, Irvine, CA), Trifecta and Biocor Epic (St. Jude Medical, Minneapolis, MN), and Hancock II and Mosaic (Medtronic, Minneapolis, MN). High-pressure balloons Tru Dilation, Atlas Gold, and Dorado (C.R. Bard, Murray Hill, NJ) were used to determine which valves could be fractured and at what pressure fracture occurred. Mitroflow, Magna, Magna Ease, Mosaic, and Biocor Epic surgical valves were successfully fractured using high-pressures balloon 1 mm larger than the labeled valve size whereas Trifecta and Hancock II surgical valves could not be fractured. Only the internal valve frame was fractured, and the sewing cuff was never disrupted. Manufacturer's rated burst pressures for balloons were exceeded, with fracture pressures ranging from 8 to 24 atmospheres depending on the surgical valve. Testing further demonstrated that fracture facilitated the expansion of previously constrained, underexpanded transcatheter valves (both balloon and self-expanding) to the manufacturer's recommended size. Bench testing demonstrates that the frame of most, but not all, bioprosthetic surgical aortic valves can be fractured using high-pressure balloons. The safety of bioprosthetic valve fracture to optimize valve-in-valve transcatheter aortic valve replacement in small surgical valves requires further clinical investigation. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

JenaValve.

PubMed

Treede, Hendrik; Rastan, Ardawan; Ferrari, Markus; Ensminger, Stephan; Figulla, Hans-Reiner; Mohr, Friedrich-Wilhelm

2012-09-01

The JenaValve is a next-generation TAVI device which consists of a well-proven porcine root valve mounted on a low-profile nitinol stent. Feeler guided positioning and clip fixation on the diseased leaflets allow for anatomically correct implantation of the device without rapid pacing. Safety and efficacy of transapical aortic valve implantation using the JenaValve were evaluated in a multicentre prospective study that showed good short and midterm results. The valve was CE-mark released in Europe in September 2011. A post-market registry ensures on-going and prospective data collection in "real-world" patients. The transfemoral JenaValve delivery system will be evaluated in a first-in-man study in the near future.

The challenge of valve-in-valve procedures in degenerated Mitroflow bioprostheses and the advantage of using the JenaValve transcatheter heart valve.

PubMed

Conradi, Lenard; Kloth, Benjamin; Seiffert, Moritz; Schirmer, Johannes; Koschyk, Dietmar; Blankenberg, Stefan; Reichenspurner, Hermann; Diemert, Patrick; Treede, Hendrik

2014-12-01

Recently, the feasibility of valve-in-valve procedures using current first-generation transcatheter heart valves (THV) in cases of structural valve degeneration has been reported as an alternative to conventional open repeat valve replacement. By design, certain biological valve xenografts carry a high risk of coronary ostia occlusion due to lateral displacement of leaflets after valve-in-valve procedures. In the present report we aimed to prove feasibility and safety of transapical valve-in-valve implantation of the JenaValve THV in two cases of degenerated Mitroflow bioprostheses. We herein report two cases of successful transapical valve-in-valve procedures using a JenaValve THV implanted in Sorin Mitroflow bioprostheses for structural valve degeneration. Both patients were alive and in good clinical condition at 30 days from the procedure. However, increased transvalvular gradients were noted in both cases. Transcatheter valve-in-valve implantation of a JenaValve THV is a valid alternative for patients with degenerated Mitroflow bioprostheses of sufficient size and in the presence of short distances to the coronary ostia who are too ill for conventional repeat open heart surgery. Increased pressure gradients have to be expected and weighed against the disadvantages of other treatment options when planning such a procedure.

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

PubMed

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.

Valve in valve transcatheter aortic valve implantation (ViV-TAVI) versus redo-Surgical aortic valve replacement (redo-SAVR): A systematic review and meta-analysis.

PubMed

Nalluri, Nikhil; Atti, Varunsiri; Munir, Abdullah B; Karam, Boutros; Patel, Nileshkumar J; Kumar, Varun; Vemula, Praveen; Edla, Sushruth; Asti, Deepak; Paturu, Amrutha; Gayam, Sriramya; Spagnola, Jonathan; Barsoum, Emad; Maniatis, Gregory A; Tamburrino, Frank; Kandov, Ruben; Lafferty, James; Kliger, Chad

2018-05-20

Bioprosthetic (BP) valves have been increasingly used for aortic valve replacement over the last decade. Due to their limited durability, patients presenting with failed BP valves are rising. Valve in Valve - Transcatheter Aortic Valve Implantation (ViV-TAVI) emerged as an alternative to the gold standard redo-Surgical Aortic Valve Replacement (redo-SAVR). However, the utility of ViV-TAVI is poorly understood. A systematic electronic search of the scientific literature was done in PubMed, EMBASE, SCOPUS, Google Scholar, and ClinicalTrials.gov. Only studies which compared the safety and efficacy of ViV-TAVI and redo-SAVR head to head in failed BP valves were included. Six observational studies were eligible and included 594 patients, of whom 255 underwent ViV- TAVI and 339 underwent redo-SAVR. There was no significant difference between ViV-TAVI and redo- SAVR for procedural, 30 day and 1 year mortality rates. ViV-TAVI was associated with lower risk of permanent pacemaker implantation (PPI) (OR: 0.43, CI: 0.21-0.89; P = 0.02) and a trend toward increased risk of paravalvular leak (PVL) (OR: 5.45, CI: 0.94-31.58; P = 0.06). There was no significant difference for stroke, major bleeding, vascular complications and postprocedural aortic valvular gradients more than 20 mm-hg. Our results reiterate the safety and feasibility of ViV-TAVI for failed aortic BP valves in patients deemed to be at high risk for surgery. VIV-TAVI was associated with lower risk of permanent pacemaker implantation with a trend toward increased risk of paravalvular leak. © 2018, Wiley Periodicals, Inc.

Evaluation of the safety and efficacy of transcatheter aortic valve implantation in patients with a severe stenotic bicuspid aortic valve in a Chinese population*

PubMed Central

Liu, Xian-bao; Jiang, Ju-bo; Zhou, Qi-jing; Pu, Zhao-xia; He, Wei; Dong, Ai-qiang; Feng, Yan; Jiang, Jun; Sun, Yong; Xiang, Mei-xiang; He, Yu-xin; Fan, You-qi; Dong, Liang; Wang, Jian-an

2015-01-01

Objective: The purpose of this study is to evaluate the safety and efficacy of transcatheter aortic valve implantation (TAVI) in patients with a severe stenotic bicuspid aortic valve (BAV) in a Chinese population. While several groups have reported the feasibility, efficacy, and safety of TAVI for patients with a BAV, worldwide experience of the technique is still limited, especially in China. Methods: From March 2013 to November 2014, high surgical risk or inoperable patients with symptomatic severe aortic stenosis (AS) who had undergone TAVI at our institution were selected for inclusion in our study. Results were compared between a BAV group and a tricuspid aortic valve (TAV) group. Results: Forty patients were included in this study, 15 (37.5%) of whom were identified as having a BAV. In the BAV group, the aortic valve area was smaller ((0.47±0.13) vs. (0.59±0.14) cm2), the ascending aortic diameter was larger ((40.4±4.4) vs. (36.4±4.3) mm), and the concomitant aortic regurgitation was lower. No significant differences were found between the groups in the other baseline characteristics. No differences were observed either in the choice of access or valve size. The procedural success achieved in this study was 100%. There were no differences between groups in device success (86.7% vs. 88.0%), 30-d mortality (6.7% vs. 8.0%), or 30-d combined end point (13.3% vs. 12.0%). The incidences of new pacemaker implantation, paravalvular regurgitation and other complications, recovery of left ventricle ejection fraction and heart function were similar in both groups. Conclusions: Patients with a severely stenotic BAV can be treated with TAVI, and their condition after treatment should be similar to that of people with a TAV. PMID:25743122

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.

PubMed

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 < 0.05); this was mainly due to less second THV implantations and a lower rate of moderate to severe paravalvular regurgitation (10% vs. 24% and 3% vs. 27%, respectively). Independent predictors of 30-day mortality were body mass index <20 kg/m 2 , STS surgical risk score >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.

77 FR 5472 - Pipeline Safety: Expanding the Use of Excess Flow Valves in Gas Distribution Systems to...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-03

..., Regulatory Certainty, and Job Creation Act of 2011 (PL112-90), have imposed additional demands on their... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration 49 CFR Part 192 [Docket ID PHMSA-2011-0009] RIN 2137-AE71 Pipeline Safety: Expanding the Use of Excess Flow Valves...

Single and two-phase flows of shear-thinning media in safety valves.

PubMed

Moncalvo, D; Friedel, L

2009-09-15

This study is the first one in the scientific literature to investigate the liquid and two-phase flows of shear-thinning media, here aqueous solutions of polyvinylpyrrolidone, in a fully opened safety valve. In liquid flows the volume flux at the valve seat does not show any appreciable reduction when increasing the percental weight of polymer in the solution. This result may suggest that the viscous losses in the valve do not increase sensibly from the most aqueous to the most viscous solution. The authors explain it considering that in the region between the seat and the disk, where large pressure and velocity gradients occur, large shear rates are expected. On behalf of the rheological measurements, which show that both the pseudoplasticity and the zero-shear viscosity of the solutions increase with the polymer weight, the difference between the viscosities of the most viscous and those of the most aqueous solution is between the seat and the disk far less than that existing at zero-shear condition. Therefore, the effective viscous pressure drop of the safety valve, which occurs mostly in that region, must increase only modestly with the polymer percental weight in the solution. In two-phase flows the total mass flow rate at constant quality and constant relieving pressure increases remarkably with the polymer weight. The analogy with similar results in cocurrent pipe flows suggests that air entrainment causes large velocity gradients in the liquids and strains them to very large shear rates. It suggests also that a redistribution of the gas agglomerates within the liquid must be expected when increasing the polymer weight in the solutions. In fact, the gas agglomerates react to the larger viscous drag of the liquid by compressing their volume in order to exert a higher internal pressure. The reduction of the void fraction of the mixture at constant quality and constant relieving pressure imposes an increment in the total mass flow rate, since otherwise it would

Design and development of a large diameter high pressure fast acting propulsion valve and valve actuator

NASA Technical Reports Server (NTRS)

Srinivasan, K. V.

1986-01-01

The design and development of a large diameter high pressure quick acting propulsion valve and valve actuator is described. The valve is the heart of a major test facility dedicated to conducting full scale performance tests of aircraft landing systems. The valve opens in less than 300 milliseconds releasing a 46-centimeter- (18-in.-) diameter water jet and closes in 300 milliseconds. The four main components of the valve, i.e., valve body, safety shutter, high speed shutter, and pneumatic-hydraulic actuator, are discussed. This valve is unique and may have other aerospace and industrial applications.

Design and Development of a Large Diameter, High Pressure, Fast Acting Propulsion Valve and Valve Actuator

NASA Technical Reports Server (NTRS)

Srinivasan, K. V.

1986-01-01

This paper describes the design and development of a large diameter high pressure quick acting propulsion valve and valve actuator. The valve is the heart of a major test facility dedicated to conducting full scale performance tests of aircraft landing gear systems. The valve opens in less than 300 milliseconds releasing a 46 cm (18 in) diameter water jet and closes in 300 milliseconds. The four main components of the valve, i.e., valve body, safety shutter, high speed shutter, and pneumatic-hydraulic actuator, are discussed. This valve is unique and may have other aerospace and industrial applications.

Mitral valve surgery using right anterolateral thoracotomy: is the aortic cannulation a safety procedure?

PubMed

Guedes, Marco Antonio Vieira; Pomerantzeff, Pablo Maria Alberto; Brandão, Carlos Manuel de Almeida; Vieira, Marcelo Luiz Campos; Grinberg, Max; Stolf, Noedir Antonio Groppo

2010-01-01

The right anterolateral thoracotomy is an alternative technique for surgical approach of mitral valve. In these cases, femoral-femoral bypass still has been used, rising occurrence of complications related to femoral cannulation. Describe the technique and results of mitral valve treatment by right anterolateral thoracotomy using aortic cannulation for cardiac pulmonary bypass (CPB). From 1983 e 2008, 100 consecutive female patients, with average age 35 ±13 years, 96 (96%) underwent mitral valve surgical treatment in the Heart Institute of São Paulo. A right anterolateral thoracotomy approach associated with aortic cannulation was used for CPB. Eighty (80%) patients had rheumatic disease and 84 (84%) patients presented functional class III or IV. Were performed 45 (45%) comissurotomies, 38 (38%) valve repairs, 7(7%) mitral valve replacements, seven (7%) recomissurotomies and three (3%) prosthesis replacement. Sparing surgery was performed in 90 (90%) patients. The average CPB and clamp time were 57 ± 27 min e 39 ± 19 min, respectively. There were no in-hospital death, reoperation due to bleeding and convertion to sternotomy. Introperative complications were related to heart harvest (5%), especially in reoperations (3%). The most important complications in postoperative period were related to pulmonary system (11%), followed by atrial fibrilation (10%) but without major systemic repercussions. The mean inhospital length of stay was 8 ± 3 days. Follow-up was 6.038 patients/month. Actuarial survival was 98.0 ± 1.9% and freedom from reoperation was 81.4 ± 7.8% in 180 months. The right anterolateral thoracotomy associated with aortic cannulation in mitral valve surgery is a simple technique, reproducible and safety.

Thermal overload protection for electric motors on safety-related motor-operated valves: Generic Issue II. E. 6. 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rothberg, O.

1988-06-01

NRC regulatory positions, as stated in Regulatory Guide 1.106, Revision 1, have been identified by the Office for Analysis and Evaluation of Operational Data (AEOD) as potential contributors to valve motor burnout. AEOD is particularly concerned about the allowed policy of bypassing thermal overload devices during normal or accident conditions. Regulatory Guide 1.106 favors compromising the function of thermal overload devices in favor of completing the safety-related action of valves. The purpose of this study was to determine if the guidance contained in Regulatory Guide 1.106 is appropriate and, if not, to recommend the necessary changes. This report describes thermalmore » overload devices commonly used to protect safety-related valve operator motors. The regulatory guidelines stated in Regulatory Guide 1.106 along with the limitations of thermal overload protection are discussed. Supplements and alternatives to thermal overload protection are also described. Findings and conclusions of several AEOD reports are discussed. Information obtained from the standard review plan, standard technical specifications, technical specifications from representative plants, and several papers are cited.« less

Navier-Stokes flow field analysis of compressible flow in a high pressure safety relief valve

NASA Technical Reports Server (NTRS)

Vu, Bruce; Wang, Ten-See; Shih, Ming-Hsin; Soni, Bharat

1993-01-01

The objective of this study is to investigate the complex three-dimensional flowfield of an oxygen safety pressure relieve valve during an incident, with a computational fluid dynamic (CFD) analysis. Specifically, the analysis will provide a flow pattern that would lead to the expansion of the eventual erosion pattern of the hardware, so as to combine it with other findings to piece together a most likely scenario for the investigation. The CFD model is a pressure based solver. An adaptive upwind difference scheme is employed for the spatial discretization, and a predictor, multiple corrector method is used for the velocity-pressure coupling. The computational result indicated vortices formation near the opening of the valve which matched the erosion pattern of the damaged hardware.

33 CFR 183.528 - Fuel stop valves.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Fuel stop valves. 183.528 Section...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.528 Fuel stop valves. (a) Each electrically operated fuel stop valve in a fuel line between the fuel tank and the engine...

76 FR 72666 - Pipeline Safety: Expanding the Use of Excess Flow Valves in Gas Distribution Systems to...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-25

... technical feasibility and cost of the installation of such valves; (D) The public safety benefits of the... public comment regarding the technical challenges, and the potential costs and the potential benefits of... a cost-benefit perspective. DATES: Persons interested in submitting written comments on this ANPRM...

46 CFR 98.25-40 - Valves, fittings, and accessories.

Code of Federal Regulations, 2013 CFR

2013-10-01

... located at the highest practical point. The thermometer well shall terminate in the liquid space and be... and discharge liquid and vapor shut-off valves, safety relief valves, liquid level gaging devices... to the tanks, except safety devices and liquid level gaging devices, shall have manually operated...

46 CFR 98.25-40 - Valves, fittings, and accessories.

Code of Federal Regulations, 2012 CFR

2012-10-01

... located at the highest practical point. The thermometer well shall terminate in the liquid space and be... and discharge liquid and vapor shut-off valves, safety relief valves, liquid level gaging devices... to the tanks, except safety devices and liquid level gaging devices, shall have manually operated...

46 CFR 98.25-40 - Valves, fittings, and accessories.

Code of Federal Regulations, 2011 CFR

2011-10-01

... located at the highest practical point. The thermometer well shall terminate in the liquid space and be... and discharge liquid and vapor shut-off valves, safety relief valves, liquid level gaging devices... to the tanks, except safety devices and liquid level gaging devices, shall have manually operated...

46 CFR 98.25-40 - Valves, fittings, and accessories.

Code of Federal Regulations, 2014 CFR

2014-10-01

... located at the highest practical point. The thermometer well shall terminate in the liquid space and be... and discharge liquid and vapor shut-off valves, safety relief valves, liquid level gaging devices... to the tanks, except safety devices and liquid level gaging devices, shall have manually operated...

High cleanliness globe valve with sine mechanism drive

NASA Astrophysics Data System (ADS)

Luo, Hu

2018-06-01

This paper gives a new type of quick-opening globe valve for life support pneumatic control system of the safety cabin at underground coal mine. The valve adopts the sine mechanism to transmit the rotating of the handle in the range of 90° to the reciprocating motion of the spool. The mechanism implements the quick-opening function of the valve through controlling the contact and separation between the O-ring and the end face of the valve. Since there is no relative sliding between the sealing interfaces, the valve solute uncontrollable disadvantage wear particles which produced by package ball valve, to ensure high cleanliness in flow path. Traditional transmission mechanism has a reinforcement effect and reduce handle open torque. By the finite element method, the relationship between the contact force and the compression of O-ring is analyzed to provide the boundary condition for the calculation of the rotational torque. Meanwhile the velocity field and pressure field along the flow path are simulated. The caliber size of the valve and the flow resistance coefficient are obtained. There is higher cleanliness, more reliable sealing, smaller handle open torque advantage compared with existing packing ball valve. The above work presents a new technical approach for the design of pneumatic control valve of the safety cabin.

14 CFR 121.239 - Oil valves.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions are...

14 CFR 121.239 - Oil valves.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions are...

14 CFR 121.239 - Oil valves.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions are...

14 CFR 121.239 - Oil valves.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions are...

14 CFR 121.239 - Oil valves.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil... oil shutoff means must not prevent feathering the propeller, unless equivalent safety provisions are...

Propellant actuated nuclear reactor steam depressurization valve

DOEpatents

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.

49 CFR 179.220-24 - Tests of pressure relief valves.

Code of Federal Regulations, 2012 CFR

2012-10-01

... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-24 Tests of pressure relief valves. Each safety relief valve must be tested by air or gas for compliance with § 179.15...

49 CFR 179.220-24 - Tests of pressure relief valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-24 Tests of pressure relief valves. Each safety relief valve must be tested by air or gas for compliance with § 179.15...

49 CFR 192.179 - Transmission line valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.179 Transmission line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing block... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission line valves. 192.179 Section 192.179...

49 CFR 192.179 - Transmission line valves.

Code of Federal Regulations, 2013 CFR

2013-10-01

... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.179 Transmission line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing block... 49 Transportation 3 2013-10-01 2013-10-01 false Transmission line valves. 192.179 Section 192.179...

49 CFR 192.179 - Transmission line valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.179 Transmission line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing block... 49 Transportation 3 2011-10-01 2011-10-01 false Transmission line valves. 192.179 Section 192.179...

49 CFR 192.179 - Transmission line valves.

Code of Federal Regulations, 2014 CFR

2014-10-01

... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.179 Transmission line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing block... 49 Transportation 3 2014-10-01 2014-10-01 false Transmission line valves. 192.179 Section 192.179...

49 CFR 192.179 - Transmission line valves.

Code of Federal Regulations, 2012 CFR

2012-10-01

... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.179 Transmission line valves. (a) Each transmission line, other than offshore segments, must have sectionalizing block... 49 Transportation 3 2012-10-01 2012-10-01 false Transmission line valves. 192.179 Section 192.179...

Refuge alternatives relief valve testing and design

PubMed Central

Lutz, T.J.; Bissert, P.T.; Homce, G.T.; Yonkey, J.A.

2016-01-01

The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer’s steel prefabricated RAs and had been adapted for use in one mine operator’s built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer’s specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster. PMID:28018003

The JUPITER registry: One-year outcomes of transapical aortic valve implantation using a second generation transcatheter heart valve for aortic regurgitation.

PubMed

Silaschi, Miriam; Conradi, Lenard; Wendler, Olaf; Schlingloff, Friederike; Kappert, Utz; Rastan, Ardawan J; Baumbach, Hardy; Holzhey, David; Eichinger, Walter; Bader, Ralf; Treede, Hendrik

2018-06-01

We present 1-year outcomes of the post-market registry of a next-generation transcatheter heart valve used for aortic regurgitation (AR). Transcatheter aortic valve replacement (TAVR) is routine in high-risk patients with aortic stenosis but is not recommended for AR. The JenaValve™ (JenaValve Technology GmbH, Munich, Germany) overcomes technical challenges in AR patients through a leaflet clipping mechanism. The JenaValve EvalUation of Long Term Performance and Safety In PaTients with SEvere Aortic Stenosis oR Aortic Insufficiency (JUPITER) Registry is a European study to evaluate safety and effectiveness of this THV. From 2012-2015, 30 patients with AR were enrolled. Mean age was 74.4 ± 9.3 years. Procedural success was 96.7% (29/30). One patient was converted to open surgery. No annular rupture or coronary ostia obstruction occurred. Mortality at 30 days was 10.0% (3/30). Combined safety endpoint was met in 13.3% (4/30). Paravalvular regurgitation was not present/trivial in 84.6% (22/26) and mild in 15.4% (4/26). Rate of permanent pacemaker implantation was 3.8% (1/26). One-year Kaplan-Meier survival was 79.9%, one-year combined efficacy was 73.1% (19/30). No further strokes were observed during 1 year of follow-up. The JenaValve overcomes technical challenges of TAVR in AR through a clipping mechanism. We report satisfactory outcomes of a multicenter registry using the JenaValve for predominant AR, as rate of THV embolization, residual AR and permanent pacemaker implantation was low. One-year results using the JenaValve for AR encourage its use for this indication. © 2017 Wiley Periodicals, Inc.

49 CFR 236.383 - Valve locks, valves, and valve magnets.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall be...

30 CFR 57.4603 - Closure of valves.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Closure of valves. 57.4603 Section 57.4603 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...

30 CFR 56.4603 - Closure of valves.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Closure of valves. 56.4603 Section 56.4603 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...

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

PubMed

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.

Valve leakage inspection, testing, and maintenance process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aikin, J.A.; Reinwald, J.W.

1989-01-01

Atomic Energy of Canada Limited-Research Company (AECL-RC), Chalk River, has more than 50 person-years dedicated toward the leak-free valve. In the early 1970s, the Chalk River Nuclear Laboratories (CRNL) developed valve stem live-loading and recently completed the packing tests for the Electric Power Research Institute (EPRI)-funded Valve Packing Improvement Study. Current safety concerns with asbestos-based valve packings and the difficulty in removing newer graphite packings prompted CRNL to investigate methods to improve valve repacking procedures. The present practice of valve packing replacement is very labor-intensive, requiring use of hand tools such as corkscrew devices and special packing picks. Use ofmore » water jets to cut or fragment the packing for withdrawal from the stuffing box does improve the process, but removal of the lantern or junk rings is still difficult. To address these problems, AECL-RC has developed a unique valve maintenance process designed to reduce person-rem exposures, the risk of scoring the stem or stuffing box, and maintenance costs and to improve the engineering quality of valve repair.« less

Statistical Performance Evaluation Of Soft Seat Pressure Relief Valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Stephen P.; Gross, Robert E.

2013-03-26

Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated pressure relief valves at the United States Department of Energy's Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated pressure relief valves. These pressure relief valves are typically smaller and of lower cost than hard seat (metal to metal) pressure relief valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the pressure relief valve fails to perform its intendedmore » safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat valves. The research in this paper shows that the proportion of soft seat spring operated pressure relief valves failing is the same or less than that of hard seat valves, and that for failed valves, soft seat valves typically have failure ratios of proof test pressure to set pressure less than that of hard seat valves.« less

Development of a fast valve for mitigating disruptions in tokamaks

NASA Astrophysics Data System (ADS)

Savtchkov, A.; Finken, K. H.; Mank, G.

2002-10-01

In support of our disruption mitigation profram, a fast gas valve has been constructed and tested on TEXTOR at FZJ Juelich. Its main features have been shown to be: (1) rapid response time: 0.5 ms; (2) amount of injected gas: variable, 2-1000 mbar×l; (3) linear dependence of the number of injected particles on the gas pressure; (4) capability of working in a strong magnetic field; (5) sort of gas: any. The valve has the standard CF 35 flange, commonly used in vacuum engineering. All the components that have contact with vacuum were made of stainless steel, except for the closing aluminum piston. To prevent gas leaking directly from the bottles to the experimental vessel there are also two safety valves, closing the bottles before the shot. The required control equipment includes a high power supply and the combined controller for the safety valves and baratrons, both being able to work with TTL control signals. During tests and experiments on TEXTOR and ASDEX-Upgrade, the valve showed successful operation with three gas types: He, Ne, Ar.

Thrombolytic therapy for mitral valve thrombosis.

PubMed

Lin, T K; Tsai, L M; Chen, J H; Yang, Y J

1997-05-01

A 44-year-old man with a St. Jude mitral valve was admitted because of progressive pulmonary edema. He was diagnosed with prosthetic heart valve thrombosis (PHVT) based on the findings of "muffled" prosthetic valve clicks. Doppler echocardiographic evidence of severe mitral stenosis and transesophageal echocardiographic evidence of limited mitral valve motility. Because the patient hesitated to undergo our recommended surgical treatment, he was immediately treated with intravenous recombinant tissue plasminogen activator (100 mg over 3 h) followed by heparinization. Two hours after the thrombolytic therapy, the prosthetic valve clicks became clearly audible and his congestive symptoms were dramatically improved. Follow-up echocardiography no longer-showed significant mitral valve obstruction. A transient cerebral ischemic attack occurred at the end of thrombolytic therapy but there were no neurologic sequalae. The patient, on warfarin therapy, was well at follow-up 8 months after discharge. Surgical intervention has long been the standard therapy for patients with PHVT. Our case experience suggests that thrombolytic therapy may be considered as an effective alternative to surgical intervention for selected patients with PHVT. In this report, we also review the current literature regarding the indications, effectiveness and safety of thrombolytic therapy in PHVT.

Development Specification for RV-346/348 Positive Pressure Relief Valves (PPRV)

NASA Technical Reports Server (NTRS)

Ralston, Russell L.

2017-01-01

This specification establishes the requirements for design, performance, safety, testing, and manufacture of the RV-346 and RV-348, Positive Pressure Relief Valve (PPRV) as part of the Advanced Extravehicular Mobility Unit (EMU)(AEMU) Portable Life Support System (PLSS). The RV-346 serves as the Positive Pressure Relief Valve (PPRV), and the RV-348 serves as the Secondary Positive Pressure Relief Valve (SPPRV).

Flavodiiron proteins act as safety valve for electrons in Physcomitrella patens.

PubMed

Gerotto, Caterina; Alboresi, Alessandro; Meneghesso, Andrea; Jokel, Martina; Suorsa, Marjaana; Aro, Eva-Mari; Morosinotto, Tomas

2016-10-25

Photosynthetic organisms support cell metabolism by harvesting sunlight to fuel the photosynthetic electron transport. The flow of excitation energy and electrons in the photosynthetic apparatus needs to be continuously modulated to respond to dynamics of environmental conditions, and Flavodiiron (FLV) proteins are seminal components of this regulatory machinery in cyanobacteria. FLVs were lost during evolution by flowering plants, but are still present in nonvascular plants such as Physcomitrella patens We generated P. patens mutants depleted in FLV proteins, showing their function as an electron sink downstream of photosystem I for the first seconds after a change in light intensity. flv knock-out plants showed impaired growth and photosystem I photoinhibition when exposed to fluctuating light, demonstrating FLV's biological role as a safety valve from excess electrons on illumination changes. The lack of FLVs was partially compensated for by an increased cyclic electron transport, suggesting that in flowering plants, the FLV's role was taken by other alternative electron routes.

Flavodiiron proteins act as safety valve for electrons in Physcomitrella patens

PubMed Central

Gerotto, Caterina; Meneghesso, Andrea; Jokel, Martina; Suorsa, Marjaana; Aro, Eva-Mari

2016-01-01

Photosynthetic organisms support cell metabolism by harvesting sunlight to fuel the photosynthetic electron transport. The flow of excitation energy and electrons in the photosynthetic apparatus needs to be continuously modulated to respond to dynamics of environmental conditions, and Flavodiiron (FLV) proteins are seminal components of this regulatory machinery in cyanobacteria. FLVs were lost during evolution by flowering plants, but are still present in nonvascular plants such as Physcomitrella patens. We generated P. patens mutants depleted in FLV proteins, showing their function as an electron sink downstream of photosystem I for the first seconds after a change in light intensity. flv knock-out plants showed impaired growth and photosystem I photoinhibition when exposed to fluctuating light, demonstrating FLV’s biological role as a safety valve from excess electrons on illumination changes. The lack of FLVs was partially compensated for by an increased cyclic electron transport, suggesting that in flowering plants, the FLV’s role was taken by other alternative electron routes. PMID:27791022

Refuge alternatives relief valve testing and design with updated test stand.

PubMed

Lutz, T J; Bissert, P T; Homce, G T; Yonkey, J A

2018-03-01

Underground refuge alternatives require an air source to supply breathable air to the occupants. This requires pressure relief valves to prevent unsafe pressures from building up within the refuge alternative. The U.S. Mine Safety and Health Administration (MSHA) mandates that pressure relief valves prevent pressure from exceeding 1.25 kPa (0.18 psi), or as specified by the manufacturer, above mine atmospheric pressure when a fan or compressor is used for the air supply. The U.S. National Institute for Occupational Safety and Health (NIOSH) tested a variety of pressure relief valves using an instrumented test fixture consisting of data acquisition equipment, a centrifugal blower, ductwork and various sensors to determine if the subject pressure relief valves meet the MSHA requirement. Relief pressures and flow characteristics, including opening pressure and flow rate, were measured for five different pressure relief valves under a variety of conditions. The subject pressure relief valves included two off-the-shelf modified check valves, two check valves used in MSHA-approved built-in-place refuge alternatives, and a commercially available valve that was designed for a steel refuge alternative and is currently being used in some built-in-place refuge alternatives. The test results showed relief pressures ranging from 0.20 to 1.53 kPa (0.03 to 0.22 psi) and flow rates up to 19.3 m 3 /min (683 scfm). As tested, some of the pressure relief valves did not meet the 1.25 kPa (0.18 psi) relief specification.

Refuge alternatives relief valve testing and design with updated test stand

PubMed Central

Lutz, T.J.; Bissert, P.T.; Homce, G.T.; Yonkey, J.A.

2018-01-01

Underground refuge alternatives require an air source to supply breathable air to the occupants. This requires pressure relief valves to prevent unsafe pressures from building up within the refuge alternative. The U.S. Mine Safety and Health Administration (MSHA) mandates that pressure relief valves prevent pressure from exceeding 1.25 kPa (0.18 psi), or as specified by the manufacturer, above mine atmospheric pressure when a fan or compressor is used for the air supply. The U.S. National Institute for Occupational Safety and Health (NIOSH) tested a variety of pressure relief valves using an instrumented test fixture consisting of data acquisition equipment, a centrifugal blower, ductwork and various sensors to determine if the subject pressure relief valves meet the MSHA requirement. Relief pressures and flow characteristics, including opening pressure and flow rate, were measured for five different pressure relief valves under a variety of conditions. The subject pressure relief valves included two off-the-shelf modified check valves, two check valves used in MSHA-approved built-in-place refuge alternatives, and a commercially available valve that was designed for a steel refuge alternative and is currently being used in some built-in-place refuge alternatives. The test results showed relief pressures ranging from 0.20 to 1.53 kPa (0.03 to 0.22 psi) and flow rates up to 19.3 m3/min (683 scfm). As tested, some of the pressure relief valves did not meet the 1.25 kPa (0.18 psi) relief specification. PMID:29563650

Bioprosthetic Valve Fracture Improves the Hemodynamic Results of Valve-in-Valve Transcatheter Aortic Valve Replacement.

PubMed

Chhatriwalla, Adnan K; Allen, Keith B; Saxon, John T; Cohen, David J; Aggarwal, Sanjeev; Hart, Anthony J; Baron, Suzanne J; Dvir, Danny; Borkon, A Michael

2017-07-01

Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) may be less effective in small surgical valves because of patient/prosthesis mismatch. Bioprosthetic valve fracture (BVF) using a high-pressure balloon can be performed to facilitate VIV TAVR. We report data from 20 consecutive clinical cases in which BVF was successfully performed before or after VIV TAVR by inflation of a high-pressure balloon positioned across the valve ring during rapid ventricular pacing. Hemodynamic measurements and calculation of the valve effective orifice area were performed at baseline, immediately after VIV TAVR, and after BVF. BVF was successfully performed in 20 patients undergoing VIV TAVR with balloon-expandable (n=8) or self-expanding (n=12) transcatheter valves in Mitroflow, Carpentier-Edwards Perimount, Magna and Magna Ease, Biocor Epic and Biocor Epic Supra, and Mosaic surgical valves. Successful fracture was noted fluoroscopically when the waist of the balloon released and by a sudden drop in inflation pressure, often accompanied by an audible snap. BVF resulted in a reduction in the mean transvalvular gradient (from 20.5±7.4 to 6.7±3.7 mm Hg, P <0.001) and an increase in valve effective orifice area (from 1.0±0.4 to 1.8±0.6 cm 2 , P <0.001). No procedural complications were reported. BVF can be performed safely in small surgical valves to facilitate VIV TAVR with either balloon-expandable or self-expanding transcatheter valves and results in reduced residual transvalvular gradients and increased valve effective orifice area. © 2017 American Heart Association, Inc.

Efficacy and safety of programmable shunt valves for hydrocephalus: A meta-analysis.

PubMed

Li, Min; Wang, Han; Ouyang, Yetong; Yin, Min; Yin, Xiaoping

2017-08-01

Shunt implantation is an option in the treatment of hydrocephalus. However, the benefits and adverse effects of programmable shunt valves have not been well assessed. Randomized controlled trials (RCTs) and observational studies assessing the efficacy and safety of programmable valves (PV) treatment for hydrocephalus were identified from electronic databases (PubMed, EMBASE, and Cochrane library). The meta-analysis was performed with the fixed-effect model or random-effect model according to heterogeneity. Three RCTs and eight observational studies met the inclusion criteria including 2622 subjects. Compared with non-PV, PV treatment did not have a statistically significant effect on one-year shunt survival rate [relative risk (RR), 1.06; 95% confidence interval (CI), 0.84-1.35], Substantial heterogeneity was observed between studies (P = 0.09; I 2  = 65%). PV administration significantly reduced revision rate (RR, 0.56; 95% CI, 0.45-0.69; I 2  = 29%; P = 0.23) and over- or under-drainage complications rate (RR, 0.55; 95% CI, 0.32-0.96). PV was not associated with increased rates of other adverse events, including overall complications rate, infection rate and catheter-related complications rate. PV treatment is safe and may reduce the revision rate and over- or under-drainage complication rate, especially in patients aged less than 18 years with hydrocephalus. PV treatment is not associated with decreased overall complication rates in patients with hydrocephalus, but the trial sequential analysis indicate more studies are needed to confirm this result. Copyright © 2017. Published by Elsevier Ltd.

Transcatheter Aortic Valve-in-Valve Procedure in Patients with Bioprosthetic Structural Valve Deterioration

PubMed Central

Reul, Ross M.; Ramchandani, Mahesh K.; Reardon, Michael J.

2017-01-01

Surgical aortic valve replacement is the gold standard procedure to treat patients with severe, symptomatic aortic valve stenosis or insufficiency. Bioprosthetic valves are used for surgical aortic valve replacement with a much greater prevalence than mechanical valves. However, bioprosthetic valves may fail over time because of structural valve deterioration; this often requires intervention due to severe bioprosthetic valve stenosis or regurgitation or a combination of both. In select patients, transcatheter aortic valve replacement is an alternative to surgical aortic valve replacement. Transcatheter valve-in-valve (ViV) replacement is performed by implanting a transcatheter heart valve within a failing bioprosthetic valve. The transcatheter ViV operation is a less invasive procedure compared with reoperative surgical aortic valve replacement, but it has been associated with specific complications and requires extensive preoperative work-up and planning by the heart team. Data from experimental studies and analyses of results from clinical procedures have led to strategies to improve outcomes of these procedures. The type, size, and implant position of the transcatheter valve can be optimized for individual patients with knowledge of detailed dimensions of the surgical valve and radiographic and echocardiographic measurements of the patient's anatomy. Understanding the complexities of the ViV procedure can lead surgeons to make choices during the original surgical valve implantation that can make a future ViV operation more technically feasible years before it is required. PMID:29743998

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

PubMed Central

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

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 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. Findings 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

Research on digital system design of nuclear power valve

NASA Astrophysics Data System (ADS)

Zhang, Xiaolong; Li, Yuan; Wang, Tao; Dai, Ye

2018-04-01

With the progress of China's nuclear power industry, nuclear power plant valve products is in a period of rapid development, high performance, low cost, short cycle of design requirements for nuclear power valve is proposed, so there is an urgent need for advanced digital design method and integrated design platform to provide technical support. Especially in the background of the nuclear power plant leakage in Japan, it is more practical to improve the design capability and product performance of the nuclear power valve. The finite element numerical analysis is a common and effective method for the development of nuclear power valves. Nuclear power valve has high safety, complexity of valve chamber and nonlinearity of seal joint surface. Therefore, it is urgent to establish accurate prediction models for earthquake prediction and seal failure to meet engineering accuracy and calculation conditions. In this paper, a general method of finite element modeling for nuclear power valve assembly and key components is presented, aiming at revealing the characteristics and rules of finite element modeling of nuclear power valves, and putting forward aprecision control strategy for finite element models for nuclear power valve characteristics analysis.

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

PubMed

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.

CardiaMed mechanical valve: mid-term results of a multicenter clinical trial.

PubMed

Nazarov, Vladimir M; Zheleznev, Sergey I; Bogachev-Prokophiev, Alexandr V; Afanasyev, Alexandr V; Nemchenko, Eugene V; Jeltovskiy, Yuri V; Lavinyukov, Sergey O

2014-01-01

Prosthesis choice is a major concern in valvular surgery. A multicenter clinical trial was performed to assess the efficacy and safety of the CardiaMed prosthetic heart valve. The study enrolled 420 patients who underwent mitral (209) or aortic (211) valve replacement from 2003 to 2004 at 7 institutions in Russia, and who were followed up from 2006 to 2011. The mean age was 52.2 ± 10.2 years (range, 12-78 years), 47.4% were female, and 99.05% completed the study. The maximum observation term was 7.5 years (2188.5 patient-years); 1081.6 patient-years for aortic and 1106.9 patient-years for mitral valve replacement. The overall 7-year survival rate was 85.1%  ± 3.7%; 86.1%  ± 4.8% and 84.4%  ± 5.4% for aortic and mitral valve replacement, respectively. The 7-year freedom from valve-related death was 93.9%  ± 3.7% and 94.5%  ± 3.2% for aortic and mitral valve replacement, respectively. When early mortality (<30 days) was excluded, these rates were 94.8%  ± 3.1% and 93.8%  ± 3.82%, respectively. Linearized valve-dependent complication rates were determined for structural valve failure (0%/patient-year overall), thrombosis (0.63%/patient-year, all for mitral valve replacement), thromboembolic complications including transient neurologic deficits (0.13%/patient-year overall, 0.5%/patient-year for aortic valve replacement, 0.8%/patient-year for mitral valve replacement), hemorrhagic bleeding (0.64%/patient-year overall, 0.55%/patient-year for aortic valve replacement, 0.09%/patient-year for mitral valve replacement), prosthetic endocarditis (0.28%/patient-year overall, 0.28%/patient-year for aortic valve replacement, 0%/patient-year for mitral valve replacement), and hemolysis (0%/patient-year overall). The CardiaMed mechanical heart valve prostheses meets world standards of safety and efficacy.

Early outcomes of percutaneous pulmonary valve implantation using the Edwards SAPIEN XT transcatheter heart valve system.

PubMed

Haas, Nikolaus A; Carere, Ronald Giacomo; Kretschmar, Oliver; Horlick, Eric; Rodés-Cabau, Josep; de Wolf, Daniël; Gewillig, Marc; Mullen, Michael; Lehner, Anja; Deutsch, Cornelia; Bramlage, Peter; Ewert, Peter

2018-01-01

Patients with congenital or acquired heart defects affecting the pulmonary valve and right ventricular outflow tract (RVOT) commonly require multiple surgical interventions, resulting in significant morbidity. A less invasive alternative is percutaneous pulmonary valve implantation (PPVI). Though studies have previously reported the safety and efficacy of the early generation transcatheter heart valves (THVs), data on more recent devices are severely lacking. We performed a multinational, multicentre, retrospective, observational registry analysis of patients who underwent PPVI using the Edwards SAPIEN XT THV. Of the 46 patients that were enrolled, the majority had tetralogy of Fallot as the underlying diagnosis (58.7%), and stentless xenograft as the most common RVOT anatomy (34.8%). Procedural success rate was high (93.5%), with a low frequency of periprocedural complications and adverse events (6.5% and 10.9%, respectively). At 30days post-procedure, NYHA class had improved significantly (90.6% were at NYHA I or II). The rate of moderate/severe pulmonary regurgitation had decreased from 76.1% at baseline to 5.0% at 30days, and the calculated peak systolic gradient had decreased from 45.2 (SD±21.3) mmHg to 16.4 (SD±8.0) mmHg, with these values remaining low up to 2years. The data suggest the efficacy and safety of the SAPIEN XT THV in PPVI in common anatomies in patients with conduits, as well as those with native pulmonary valves or transannular patches. Continued data collection is necessary to verify long-term findings. CLINICALTRIALS. NCT02302131. Copyright © 2017 Elsevier B.V. All rights reserved.

Excess flow valve benefit/cost analysis.

DOT National Transportation Integrated Search

1994-12-31

The Office of Pipeline Safety (OPS) is adopting regulations requiring the installation of Excess Flow Valves (EFVs) on all new or renewed single-family residential gas services that operate at pressures that are always 10 psig (pounds per square inch...

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

PubMed

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.

Quality and Safety in Health Care, Part XXIX: The Transcatheter Valve Therapy Registry.

PubMed

Harolds, Jay A

2017-11-01

The American College of Cardiology, the Society of Thoracic Surgeons, and other organizations cooperated to form the Transcatheter Valve Therapy Registry. This registry studies information on the outcome of valve therapy device placement with a transcatheter approach. The companies that manufacture these devices can use the registry to meet the post-product sale surveillance requirements of the US Food and Drug Administration. There will also be linkage to the registry information from the Society of Thoracic Surgeons Adult Cardiac Surgery Database, which has information on open cardiac valve surgery.

Will Catheter Interventions Replace Surgery for Valve Abnormalities?

PubMed Central

O’Byrne, Michael L; Gillespie, Matthew J

2015-01-01

Purpose of Review Catheter-based valve technologies have evolved rapidly over the last decade. Transcatheter aortic valve replacement (TAVR) has become a routine procedure in high-risk adult patients with calcific aortic stenosis. In patients with congenital heart disease (CHD), transcatheter pulmonary valve replacement represents a transformative technology for right ventricular outflow tract dysfunction with the potential to expand to other indications. This review aims to summarize 1) the current state of the art for transcatheter valve replacement (TVR) in CHD, 2) the expanding indications for TVR, and 3) the technological obstacles to optimizing TVR. Recent findings Multiple case series have demonstrated that TVR with the Melody transcatheter pulmonary valve in properly selected patients is safe, effective, and durable in short-term follow-up. The Sapien transcatheter heart valve represents an alternative device with similar safety and efficacy in limited studies. Innovative use of current valves has demonstrated the flexibility of TVR, while highlighting the need for devices to address the broad range of post-operative anatomies either with a single device or strategies to prepare the outflow tract for subsequent device deployment. Summary The potential of TVR has not been fully realized, but holds promise in treatment of CHD. PMID:24281347

Fracturing mechanics before valve-in-valve therapy of small aortic bioprosthetic heart valves.

PubMed

Johansen, Peter; Engholt, Henrik; Tang, Mariann; Nybo, Rasmus F; Rasmussen, Per D; Nielsen-Kudsk, Jens Erik

2017-10-13

Patients with degraded bioprosthetic heart valves (BHV) who are not candidates for valve replacement may benefit from transcatheter valve-in-valve (VIV) therapy. However, in smaller-sized surgical BHV the resultant orifice may become too narrow. To overcome this, the valve frame can be fractured by a high-pressure balloon prior to VIV. However, knowledge on fracture pressures and mechanics are prerequisites. The aim of this study was to identify the fracture pressures needed in BHV, and to describe the fracture mechanics. Commonly used BHV of small sizes were mounted on a high-pressure balloon situated in a biplane fluoroscopic system with a high-speed camera. The instant of fracture was captured along with the balloon pressure. The valves were inspected for material protrusion and later dissected for fracture zone investigation and description. The valves with a polymer frame fractured at a lower pressure (8-10 atm) than those with a metal stent (19-26 atm). None of the fractured valves had elements protruding. VIV procedures in small-sized BHV may be performed after prior fracture of the valve frame by high-pressure balloon dilatation. This study provides tentative guidelines for expected balloon sizes and pressures for valve fracturing.

Primary cooling check valve steam generator and loose parts events of November 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1985-12-23

On November 10, 1985, a primary coolant check valve, CV-3-8, was opened for inspection. The valve flapper and mounting bracket were found to have become detached from the valve body and were resting in the bottom of the valve. Normally, the bracket is secured to the valve body with three studs and nuts. All three sets of studs, nuts and stud retainers were missing. As part of the effort to locate the missing valve parts, the primary side of the No. 2A steam generator was opened for inspection. Three cap screws and an associated locking bar used to secure certainmore » internals were found to be missing. In response, the Director, Reactor Engineering Department was assigned lead responsibility for developing and directing the implementation of a plan to correct deficiencies and ready the plant to return to operation. Next, a Special Safety Assessment Team was established to provide a structured assessment of the safety aspect of the component failures and the implications of such failures to other components in the primary coolant system. This structured assessment was to result in the development of an action plan that included the development of specific safety criteria, and identification and conduct of special investigations and analyses required for recovery from the event. Finally, an independent Management Review Team was created. The purpose of this report is to document the work of the Management Review Team, including the causal factors analyses, and various reviews required to support the recovery process.« less

One-year outcomes after rapid-deployment aortic valve replacement.

PubMed

Young, Christopher; Laufer, Günther; Kocher, Alfred; Solinas, Marco; Alamanni, Francesco; Polvani, Gianluca; Podesser, Bruno K; Aramendi, Jose Ignacio; Arribas, Jose; Bouchot, Olivier; Livi, Ugolino; Massetti, Massimo; Terp, Kim; Giot, Christophe; Glauber, Mattia

2018-02-01

The goals of rapid-deployment aortic valve replacement include facilitation of minimally invasive surgery and reduced aortic crossclamp time. We report the short-term outcomes of a series of 493 patients undergoing rapid-deployment aortic valve replacement with the EDWARDS INTUITY valve system (Edwards Lifesciences, LLC, Irvine, Calif). Assessing Standard oF Care and Clinical Outcomes UsiNg the EDWARDS INTUITY VAlve SysTem in a European multI-center, Active, pOst-market surveillaNce Study was a prospective, multicenter (n = 26) European registry designed to evaluate the safety and performance of the valve system. During rapid-deployment aortic valve replacement, device technical success and crossclamp time were assessed. Procedural outcomes, hemodynamic performance, and various adverse events and clinical outcomes were evaluated up to 2 years. Between 2012 and 2014, 493 of 517 enrolled patients successfully received implants with the study valve (95.4% technical success). Mean crossclamp times for 163 full sternotomies, 128 mini-upper sternotomies, and 36 right anterior thoracotomies isolated aortic valve replacements were 47.3, 52.0, and 73.3 minutes, respectively. Mean follow-up was 1.8 years, with 870 total patient-years of follow-up. Mean effective orifice area increased from 0.72 (baseline) to 1.88 cm 2 , and mean pressure gradient decreased from 47.6 to 9.6 mm Hg (1 year). Mean effective orifice area index increased (0.39-1.01 cm 2 /m 2 ), and 28 of 287 patients (9.8%) exhibited severe prosthesis-patient mismatch at 1 year. After 1 year, 68.1% and 21.7% of patients were in New York Heart Association class I and II, respectively. Freedom from death, major bleeding, major perivalvular leak, reoperation, and device explant at 1 year were 0.935, 0.939, 0.976, 0.975, and 0.983, respectively. These results demonstrate commendable safety and performance of the test valve system over the short term in a broad European setting. Copyright © 2017 The

49 CFR 192.365 - Service lines: Location of valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators... accessible location that, if feasible, is outside of the building. (c) Underground valves. Each underground...

Check valve

DOEpatents

Upton, Hubert Allen; Garcia, Pablo

1999-08-24

A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion.

Check valve

DOEpatents

Upton, H.A.; Garcia, P.

1999-08-24

A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion. 5 figs.

Transcatheter Aortic Valve Replacement for Native Aortic Valve Regurgitation

PubMed Central

Spina, Roberto; Anthony, Chris; Muller, David WM

2015-01-01

Transcatheter aortic valve replacement with either the balloon-expandable Edwards SAPIEN XT valve, or the self-expandable CoreValve prosthesis has become the established therapeutic modality for severe aortic valve stenosis in patients who are not deemed suitable for surgical intervention due to excessively high operative risk. Native aortic valve regurgitation, defined as primary aortic incompetence not associated with aortic stenosis or failed valve replacement, on the other hand, is still considered a relative contraindication for transcatheter aortic valve therapies, because of the absence of annular or leaflet calcification required for secure anchoring of the transcatheter heart valve. In addition, severe aortic regurgitation often coexists with aortic root or ascending aorta dilatation, the treatment of which mandates operative intervention. For these reasons, transcatheter aortic valve replacement has been only sporadically used to treat pure aortic incompetence, typically on a compassionate basis and in surgically inoperable patients. More recently, however, transcatheter aortic valve replacement for native aortic valve regurgitation has been trialled with newer-generation heart valves, with encouraging results, and new ancillary devices have emerged that are designed to stabilize the annulus–root complex. In this paper we review the clinical context, technical characteristics and outcomes associated with transcatheter treatment of native aortic valve regurgitation. PMID:29588674

Fast-Acting Valve

NASA Technical Reports Server (NTRS)

Wojciechowski, Bogdan V. (Inventor); Pegg, Robert J. (Inventor)

2003-01-01

A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug. The use of a valve-plug holder that is under independent control to move the annular valve plug between its open and closed positions is important for achieving controllable fast operation of the valve.

46 CFR 154.540 - Quick-closing shut-off valves: Emergency shut-down system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design... emergency shut-down system that: (a) Closes all the valves; (b) Is actuated by a single control in at least two locations remote from the quick-closing valves; (c) Is actuated by a single control in each cargo...

46 CFR 154.540 - Quick-closing shut-off valves: Emergency shut-down system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design... emergency shut-down system that: (a) Closes all the valves; (b) Is actuated by a single control in at least two locations remote from the quick-closing valves; (c) Is actuated by a single control in each cargo...

Coincident steam generator tube rupture and stuck-open safety relief valve carryover tests: MB-2 steam generator transient response test program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garbett, K; Mendler, O J; Gardner, G C

In PWR steam generator tube rupture (SGTR) faults, a direct pathway for the release of radioactive fission products can exist if there is a coincident stuck-open safety relief valve (SORV) or if the safety relief valve is cycled. In addition to the release of fission products from the bulk steam generator water by moisture carryover, there exists the possibility that some primary coolant may be released without having first mixed with the bulk water - a process called primary coolant bypassing. The MB-2 Phase II test program was designed specifically to identify the processes for droplet carryover during SGTR faultsmore » and to provide data of sufficient accuracy for use in developing physical models and computer codes to describe activity release. The test program consisted of sixteen separate tests designed to cover a range of steady-state and transient fault conditions. These included a full SGTR/SORV transient simulation, two SGTR overfill tests, ten steady-state SGTR tests at water levels ranging from very low levels in the bundle up to those when the dryer was flooded, and three moisture carryover tests without SGTR. In these tests the influence of break location and the effect of bypassing the dryer were also studied. In a final test the behavior with respect to aerosol particles in a dry steam generator, appropriate to a severe accident fault, was investigated.« less

Outcomes following transcatheter aortic valve replacement in patients with native aortic valve regurgitation

PubMed Central

Bob-Manuel, Tamunoinemi; Kadire, Siri; Heckle, Mark R.; Wang, Jiajing

2018-01-01

Due to the absence of annular calcification for device anchoring, it is presumed that transcatheter aortic valve replacement (TAVR) is not suitable for the treatment of native aortic valve regurgitation (NAVR) resulting in very limited data and experience concerning its safety and efficacy. We sought to review published data on the safety and efficacy of TAVR in high-risk patients with NAVR. Studies including case reports, case series and original articles published between 2002 and 2016 on TAVR in patients with NAVR were identified with a systematic electronic search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Only studies reporting data on demographic and procedural characteristics, management and follow up outcomes were analyzed. A total of 30 publications describing 182 patients were identified. Most patients (54%) were men, with a mean age of 70.1±2.6 years, mean logistic European System for Cardiac Operative Risk Evaluation score (EuroSCORE) of 21.8%±4.5% and mean Society of Thoracic Surgeons (STS) score of 8%±1.8% for mortality. The majority (87%) of patients had severe NAVR with no valvular calcification. TAVR was mostly performed through the femoral (58.8%) and apical (33.1%) approach. Device success, defined by VARC-2, was achieved in 86.3% of our study population. A second valve was required in 17 patients (9.3%) during the index procedure for residual aortic regurgitation or malposition. Post-procedure aortic regurgitation of grade 1 or less was present in 80 patients (81%). Pacemaker implantation was required post procedure in 17 patients (9.3%). The 30-day and 1-year mortality was 11.9% and 16.2%, respectively. TAVR is associated with favorable pacemaker implantation and 1-year mortality rates with a high 30-day mortality among selected patients with NAVR. PMID:29404354

Safety of minimally invasive mitral valve surgery without aortic cross-clamp.

PubMed

Umakanthan, Ramanan; Leacche, Marzia; Petracek, Michael R; Kumar, Sathappan; Solenkova, Nataliya V; Kaiser, Clayton A; Greelish, James P; Balaguer, Jorge M; Ahmad, Rashid M; Ball, Stephen K; Hoff, Steven J; Absi, Tarek S; Kim, Betty S; Byrne, John G

2008-05-01

We developed a technique for open heart surgery through a small (5 cm) right-anterolateral thoracotomy without aortic cross-clamp. One hundred and ninety-five consecutive patients (103 male and 92 female), age 69 +/- 8 years, underwent surgery between January 2006 and July 2007. Mean preoperative New York Heart Association function class was 2.2 +/- 0.7. Thirty-five patients (18%) had an ejection fraction 0.35 or less. Cardiopulmonary bypass was instituted through femoral (176 of 195, 90%), axillary (18 of 195, 9%), or direct aortic (1 of 195, 0.5%) cannulation. Under cold fibrillatory arrest (mean temperature 28.2 degrees C) without aortic cross-clamp, mitral valve repair (72 of 195, 37%), mitral valve replacement (117 of 195, 60%), or other (6 of 195, 3%) procedures were performed. Concomitant procedures included maze (45 of 195, 23%), patent foramen ovale closure (42 of 195, 22%) and tricuspid valve repair (16 of 195, 8%), or replacement (4 of 195, 2%). Thirty-day mortality was 3% (6 of 195). Duration of fibrillatory arrest, cardiopulmonary bypass, and "skin to skin" surgery were 88 +/- 32, 118 +/- 52, and 280 +/- 78 minutes, respectively. Ten patients (5%) underwent reexploration for bleeding and 44% did not receive any blood transfusions. Six patients (3%) sustained a postoperative stroke, eight (4%) developed low cardiac output syndrome, and two (1%) developed renal failure requiring hemodialysis. Mean length of hospital stay was 7 +/- 4.8 days. This simplified technique of minimally invasive open heart surgery is safe and easily reproducible. Fibrillatory arrest without aortic cross-clamping, with coronary perfusion against an intact aortic valve, does not increase the risk of stroke or low cardiac output. It may be particularly useful in higher risk patients in whom sternotomy with aortic clamping is less desirable.

Bioprosthetic Valve Fracture During Valve-in-valve TAVR: Bench to Bedside

PubMed Central

Saxon, John T; Allen, Keith B; Cohen, David J

2018-01-01

Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) has been established as a safe and effective means of treating failed surgical bioprosthetic valves (BPVs) in patients at high risk for complications related to reoperation. Patients who undergo VIV TAVR are at risk of patient–prosthesis mismatch, as the transcatheter heart valve (THV) is implanted within the ring of the existing BPV, limiting full expansion and reducing the maximum achievable effective orifice area of the THV. Importantly, patient–prosthesis mismatch and high residual transvalvular gradients are associated with reduced survival following VIV TAVR. Bioprosthetic valve fracture (BVF) is as a novel technique to address this problem. During BPV, a non-compliant valvuloplasty balloon is positioned within the BPV frame, and a highpressure balloon inflation is performed to fracture the surgical sewing ring of the BPV. This allows for further expansion of the BPV as well as the implanted THV, thus increasing the maximum effective orifice area that can be achieved after VIV TAVR. This review focuses on the current evidence base for BVF to facilitate VIV TAVR, including initial bench testing, procedural technique, clinical experience and future directions. PMID:29593832

Bioprosthetic Valve Fracture During Valve-in-valve TAVR: Bench to Bedside.

PubMed

Saxon, John T; Allen, Keith B; Cohen, David J; Chhatriwalla, Adnan K

2018-01-01

Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) has been established as a safe and effective means of treating failed surgical bioprosthetic valves (BPVs) in patients at high risk for complications related to reoperation. Patients who undergo VIV TAVR are at risk of patient-prosthesis mismatch, as the transcatheter heart valve (THV) is implanted within the ring of the existing BPV, limiting full expansion and reducing the maximum achievable effective orifice area of the THV. Importantly, patient-prosthesis mismatch and high residual transvalvular gradients are associated with reduced survival following VIV TAVR. Bioprosthetic valve fracture (BVF) is as a novel technique to address this problem. During BPV, a non-compliant valvuloplasty balloon is positioned within the BPV frame, and a highpressure balloon inflation is performed to fracture the surgical sewing ring of the BPV. This allows for further expansion of the BPV as well as the implanted THV, thus increasing the maximum effective orifice area that can be achieved after VIV TAVR. This review focuses on the current evidence base for BVF to facilitate VIV TAVR, including initial bench testing, procedural technique, clinical experience and future directions.

Statins for aortic valve stenosis.

PubMed

Thiago, Luciana; Tsuji, Selma Rumiko; Nyong, Jonathan; Puga, Maria Eduarda Dos Santos; Góis, Aécio Flávio Teixeira de; Macedo, Cristiane Rufino; Valente, Orsine; Atallah, Álvaro Nagib

2016-01-01

Aortic valve stenosis is the most common type of valvular heart disease in the USA and Europe. Aortic valve stenosis is considered similar to atherosclerotic disease. Some studies have evaluated statins for aortic valve stenosis. To evaluate the effectiveness and safety of statins in aortic valve stenosis. Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS - IBECS, Web of Science and CINAHL Plus. These databases were searched from their inception to 24 November 2015. We also searched trials in registers for ongoing trials. We used no language restrictions.Selection criteria: Randomized controlled clinical trials (RCTs) comparing statins alone or in association with other systemic drugs to reduce cholesterol levels versus placebo or usual care. Data collection and analysis: Primary outcomes were severity of aortic valve stenosis (evaluated by echocardiographic criteria: mean pressure gradient, valve area and aortic jet velocity), freedom from valve replacement and death from cardiovascular cause. Secondary outcomes were hospitalization for any reason, overall mortality, adverse events and patient quality of life.Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias. The GRADE methodology was employed to assess the quality of result findings and the GRADE profiler (GRADEPRO) was used to import data from Review Manager 5.3 to create a 'Summary of findings' table. We included four RCTs with 2360 participants comparing statins (1185 participants) with placebo (1175 participants). We found low-quality evidence for our primary outcome of severity of aortic valve stenosis, evaluated by mean pressure gradient (mean difference (MD) -0.54, 95% confidence interval (CI) -1.88 to 0.80; participants = 1935; studies = 2), valve area (MD -0.07, 95% CI -0.28 to 0.14; participants = 127; studies = 2), and aortic jet velocity (MD -0.06, 95% CI -0.26 to 0

Clinical Evaluation of a Safety-device to Prevent Urinary Catheter Inflation Related Injuries.

PubMed

Davis, Niall F; Cunnane, Eoghan M; Mooney, Rory O'C; Forde, James C; Walsh, Michael T

2018-05-01

To evaluate the feasibility of a novel "safety-valve" device for preventing catheter related urethral trauma during urethral catheterization (UC). To assess the opinions of clinicians on the performance of the safety-valve device. A validated prototype "safety-valve" device for preventing catheter balloon inflation related urethral injuries was prospectively piloted in male patients requiring UC in a tertiary referral teaching hospital (n = 100). The device allows fluid in the catheter system to decant through an activated safety threshold pressure valve if the catheter anchoring balloon is misplaced. Users evaluated the "safety-valve" with an anonymous questionnaire. The primary outcome measurement was prevention of anchoring balloon inflation in the urethra. Secondary outcome measurement was successful inflation of urinary catheter anchoring balloon in the bladder. Patient age was 76 ± 12 years and American Society of Anaesthesiologists grade was 3 ± 1.4. The "safety-valve" was utilized by 34 clinicians and activated in 7% (n = 7/100) patients during attempted UC, indicating that the catheter anchoring balloon was incorrectly positioned in the patient's urethra. In these 7 cases, the catheter was successfully manipulated into the urinary bladder and inflated. 31 of 34 (91%) clinicians completed the questionnaire. Ten percent (n = 3/31) of respondents had previously inflated a urinary catheter anchoring balloon in the urethra and 100% (n = 31) felt that a safety mechanism for preventing balloon inflation in the urethra should be compulsory for all UCs. The safety-valve device piloted in this clinical study offers an effective solution for preventing catheter balloon inflation related urethral injuries. Copyright © 2018 Elsevier Inc. All rights reserved.

Control Valve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Wayne R.

A control valve includes a first conduit having a first inlet and a first outlet and defining a first passage; a second conduit having a second inlet and a second outlet and defining a second passage, the second conduit extending into the first passage such that the second inlet is located within the first passage; and a valve plate disposed pivotably within the first passage, the valve plate defining a valve plate surface. Pivoting of the valve plate within the first passage varies flow from the first inlet to the first outlet and the valve plate is pivotal between amore » first position and a second position such that in the first position the valve plate substantially prevents fluid communication between the first passage and the second passage and such that in the second position the valve plate permits fluid communication between the first passage and the second passage.« less

49 CFR 179.400-19 - Valves and gages.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-19 Valves and gages...

Nuclear radiation actuated valve

DOEpatents

Christiansen, David W.; Schively, Dixon P.

1985-01-01

A nuclear radiation actuated valve for a nuclear reactor. The valve has a valve first part (such as a valve rod with piston) and a valve second part (such as a valve tube surrounding the valve rod, with the valve tube having side slots surrounding the piston). Both valve parts have known nuclear radiation swelling characteristics. The valve's first part is positioned to receive nuclear radiation from the nuclear reactor's fuel region. The valve's second part is positioned so that its nuclear radiation induced swelling is different from that of the valve's first part. The valve's second part also is positioned so that the valve's first and second parts create a valve orifice which changes in size due to the different nuclear radiation caused swelling of the valve's first part compared to the valve's second part. The valve may be used in a nuclear reactor's core coolant system.

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

PubMed

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

Depressurization valve

DOEpatents

Skoda, G.I.

1989-03-28

A depressurization valve for use in relieving completely the pressure in a simplified boiling water reactor is disclosed. The normally closed and sealed valve is provided with a valve body defining a conduit from an outlet of a manifold from the reactor through a valve seat. A closing valve disk is configured for fitting to the valve seat to normally close the valve. The seat below the disk is provided with a radially extending annulus extending a short distance into the aperture defined by the seat. The disk is correspondingly provided with a longitudinally extending annulus that extends downwardly through the aperture defined by the seat towards the high pressure side of the valve body. A ring shaped membrane is endlessly welded to the seat annulus and to the disk annulus. The membrane is conformed over the confronted surface of the seat and disk in a C-sectioned configuration to seal the depressurization valve against the possibility of weeping. The disk is held to the closed position by an elongate stem extending away from the high pressure side of the valve body. The stem has a flange configured integrally to the stem for bias by two springs. The first spring acts from a portion of the housing overlying the disk on the stem flange adjacent the disk. This spring urges the stem and attached disk away from the seat and thus will cause the valve to open at any pressure. A second spring-preferably of the Belleville variety-acts on a latch plate surrounding and freely moving relative to the end of the stem. This second spring overcomes the bias of the first spring and any pressure acting upon the disk. This Belleville spring maintains through its spring force the valve in the closed position. At the same time, the latch plate with its freedom of movement relative to the stem allows the stem to thermally expand during valve temperature excursion.

46 CFR 56.50-25 - Safety and relief valve escape piping.

Code of Federal Regulations, 2012 CFR

2012-10-01

... discharging thereto and shall be led as near vertically as practicable to the atmosphere. (b) Expansion joints... valve discharges, when permitted to terminate in the machinery space, shall be led below the floorplates...

46 CFR 56.50-25 - Safety and relief valve escape piping.

Code of Federal Regulations, 2011 CFR

2011-10-01

... discharging thereto and shall be led as near vertically as practicable to the atmosphere. (b) Expansion joints... valve discharges, when permitted to terminate in the machinery space, shall be led below the floorplates...

46 CFR 56.50-25 - Safety and relief valve escape piping.

Code of Federal Regulations, 2014 CFR

2014-10-01

... discharging thereto and shall be led as near vertically as practicable to the atmosphere. (b) Expansion joints... valve discharges, when permitted to terminate in the machinery space, shall be led below the floorplates...

46 CFR 56.50-25 - Safety and relief valve escape piping.

Code of Federal Regulations, 2013 CFR

2013-10-01

... discharging thereto and shall be led as near vertically as practicable to the atmosphere. (b) Expansion joints... valve discharges, when permitted to terminate in the machinery space, shall be led below the floorplates...

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

NASA Astrophysics Data System (ADS)

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

2014-03-01

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

Fast valve

DOEpatents

Van Dyke, W.J.

1992-04-07

A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing. 4 figs.

Fast valve

DOEpatents

Van Dyke, William J.

1992-01-01

A fast valve is disclosed that can close on the order of 7 milliseconds. It is closed by the force of a compressed air spring with the moving parts of the valve designed to be of very light weight and the valve gate being of wedge shaped with O-ring sealed faces to provide sealing contact without metal to metal contact. The combination of the O-ring seal and an air cushion create a soft final movement of the valve closure to prevent the fast air acting valve from having a harsh closing.

42 CFR 84.123 - Exhalation valve leakage test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84...

42 CFR 84.123 - Exhalation valve leakage test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84...

42 CFR 84.123 - Exhalation valve leakage test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84...

42 CFR 84.123 - Exhalation valve leakage test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84...

42 CFR 84.123 - Exhalation valve leakage test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Exhalation valve leakage test. 84.123 Section 84.123 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Gas Masks § 84...

Stemless Ball Valve

NASA Technical Reports Server (NTRS)

Burgess, Robert K.; Yakos, David; Walthall, Bryan

2012-01-01

This invention utilizes a new method of opening and closing a ball valve. Instead of rotating the ball with a perpendicular stem (as is the case with standard ball valves), the ball is rotated around a fixed axis by two guide pins. This innovation eliminates the leak point that is present in all standard ball valves due to the penetration of an actuation stem through the valve body. The VOST (Venturi Off-Set-Technology) valve has been developed for commercial applications. The standard version of the valve consists of an off-set venturi flow path through the valve. This path is split at the narrowest portion of the venturi, allowing the section upstream from the venturi to be rotated. As this rotation takes place, the venturi becomes restricted as one face rotates with respect to the other, eventually closing off the flow path. A spring-loaded seal made of resilient material is embedded in the upstream face of the valve, making a leak-proof seal between the faces; thus a valve is formed. The spring-loaded lip seal is the only seal that can provide a class six, or bubble-tight, seal against the opposite face of the valve. Tearing action of the seal by high-velocity gas on this early design required relocation of the seal to the downstream face of the valve. In the stemless embodiment of this valve, inner and outer magnetic cartridges are employed to transfer mechanical torque from the outside of the valve to the inside without the use of a stem. This eliminates the leak path caused by the valve stems in standard valves because the stems penetrate through the bodies of these valves.

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

PubMed

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.

Depressurization valve

DOEpatents

Skoda, George I.

1989-01-01

A depressurization valve for use in relieving completely the pressure in a simplified boiling water reactor is disclosed. The normally closed and sealed valve is provided with a valve body defining a conduit from an outlet of a manifold from the reactor through a valve seat. A closing valve disk is configured for fitting to the valve seat to normally close the valve. The seat below the disk is provided with a radially extending annulus extending a short distance into the aperture defined by the seat. The disk is correspondingly provided with a longitudinally extending annulus that extends downwardly through the aperture defined by the seat towards the high pressure side of the valve body. A ring shaped membrane is endlessly welded to the seat annulus and to the disk annulus. The membrane is conformed over the confronted surface of the seat and disk in a C-sectioned configuration to seal the depressurization valve against the possibility of weeping. The disk is held to the closed position by an elongate stem extending away from the high pressure side of the valve body. The stem has a flange configured integrally to the stem for bias by two springs. The first spring acts from a portion of the housing overlying the disk on the stem flange adjacent the disk. This spring urges the stem and attached disk away from the seat and thus will cause the valve to open at any pressure. A second spring--preferably of the Belleville variety--acts on a latch plate surrounding and freely moving relative to the end of the stem. This second spring overcomes the bias of the first spring and any pressure acting upon the disk. This Belleville spring maintains through its spring force the valve in the closed position. At the same time, the latch plate with its freedom of movement relative to the stem allows the stem to thermally expand during valve temperature excursion. The latch plate in surrounding the stem is limited in its outward movement by a boss attached to the stem at the end of

Efficacy and safety of intravitreal bevacizumab in eyes with neovascular glaucoma undergoing Ahmed glaucoma valve implantation: 2-year follow-up.

PubMed

Arcieri, Enyr S; Paula, Jayter S; Jorge, Rodrigo; Barella, Kleyton A; Arcieri, Rafael S; Secches, Danilo J; Costa, Vital P

2015-02-01

To evaluate the efficacy and safety of intravitreal bevacizumab (IVB) in eyes with neovascular glaucoma (NVG) undergoing Ahmed glaucoma valve (AGV) implantation. This was a multicentre, prospective, randomized clinical trial that enrolled 40 patients with uncontrolled neovascular glaucoma that had undergone panretinal photocoagulation and required glaucoma drainage device implantation. Patients were randomized to receive IVB (1.25 mg) or not during Ahmed valve implant surgery. Injections were administered intra-operatively, and 4 and 8 weeks after surgery. After a mean follow-up of 2.25 ± 0.67 years (range 1.5-3 years), both groups showed a significant decrease in IOP (p < 0.05). There was no difference in IOP between groups except at the 18-month interval, when IOP in IVB group was significantly lower (14.57 ± 1.72 mmHg vs. 18.37 ± 1.06 mmHg - p = 0.0002). There was no difference in survival success rates between groups. At 24 months, there was a trend to patients treated with IVB using less antiglaucoma medications than the control group (p = 0.0648). Complete regression of rubeosis iridis was significantly more frequent in the IVB group (80%) than in the control group (25%) (p = 0.0015). Intravitreal bevacizumab may lead to regression of new vessels both in the iris and in the anterior chamber angle in patients with neovascular glaucoma undergoing Ahmed glaucoma valve implantation. There is a trend to slightly lower IOPs and number of medications with IVB use during AGV implantation for neovascular glaucoma. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Remotely controlled valves on interstate natural gas pipelines : September 1999.

DOT National Transportation Integrated Search

1999-09-01

This report is in response to a Congressional mandate in the : Accountable Pipeline Safety and Partnership Act of 1996 to survey : and assess the effectiveness of remotely controlled valves (RCVs) : on interstate natural gas pipelines and to determin...

Fatal association of mechanical valve thrombosis with dabigatran: a report of two cases.

PubMed

Atar, Shaul; Wishniak, Alice; Shturman, Alexander; Shtiwi, Sewaed; Brezins, Marc

2013-07-01

Several new oral anticoagulants have been approved for thromboembolism prevention in patients with nonvalvular atrial fibrillation. However, they are not yet approved for anticoagulation use in patients with prosthetic mechanical valves, and no randomized data have been published so far on their safety of use in these patients. We present two cases of patients with prosthetic mechanical mitral valves who were switched from warfarin and acenocoumarol to dabigatran and within 1 month experienced severe valve complications resulting in death. One patient experienced stroke and later cardiogenic shock and death, and the other experienced pulmonary edema, cardiogenic shock, and subsequent death.

Excess flow shutoff valve

DOEpatents

Kiffer, Micah S.; Tentarelli, Stephen Clyde

2016-02-09

Excess flow shutoff valve comprising a valve body, a valve plug, a partition, and an activation component where the valve plug, the partition, and activation component are disposed within the valve body. A suitable flow restriction is provided to create a pressure difference between the upstream end of the valve plug and the downstream end of the valve plug when fluid flows through the valve body. The pressure difference exceeds a target pressure difference needed to activate the activation component when fluid flow through the valve body is higher than a desired rate, and thereby closes the valve.

Dynamic performance of high speed solenoid valve with parallel coils

NASA Astrophysics Data System (ADS)

Kong, Xiaowu; Li, Shizhen

2014-07-01

The methods of improving the dynamic performance of high speed on/off solenoid valve include increasing the magnetic force of armature and the slew rate of coil current, decreasing the mass and stroke of moving parts. The increase of magnetic force usually leads to the decrease of current slew rate, which could increase the delay time of the dynamic response of solenoid valve. Using a high voltage to drive coil can solve this contradiction, but a high driving voltage can also lead to more cost and a decrease of safety and reliability. In this paper, a new scheme of parallel coils is investigated, in which the single coil of solenoid is replaced by parallel coils with same ampere turns. Based on the mathematic model of high speed solenoid valve, the theoretical formula for the delay time of solenoid valve is deduced. Both the theoretical analysis and the dynamic simulation show that the effect of dividing a single coil into N parallel sub-coils is close to that of driving the single coil with N times of the original driving voltage as far as the delay time of solenoid valve is concerned. A specific test bench is designed to measure the dynamic performance of high speed on/off solenoid valve. The experimental results also prove that both the delay time and switching time of the solenoid valves can be decreased greatly by adopting the parallel coil scheme. This research presents a simple and practical method to improve the dynamic performance of high speed on/off solenoid valve.

Absence of posterior tricuspid valve leaflet and valve reconstruction

PubMed Central

Komoda, Takeshi; Stamm, Christof; Fleck, Eckart; Hetzer, Roland

2012-01-01

We report a rare case of the absence of a posterior tricuspid valve leaflet. A male patient, aged 46, suffering from severe tricuspid valve regurgitation (TR) of unknown aetiology and atrial septal aneurysm was referred to our hospital for surgery. On surgical inspection, the posterior tricuspid valve leaflet and its subvalvular apparatus were completely absent and only the valve annulus was seen in the corresponding position. The anterior and septal leaflets were normal. We successfully reconstructed the tricuspid valve as follows: the head of an anterior papillary muscle was approximated to the ventricular septum (Sebening stitch). After the approximation of the centre of the tricuspid annulus of the anterior leaflet to the tricuspid annulus on the opposite side, a sizer of 29 mm in diameter was easily passed through the anterior orifice. The posterior orifice was closed with running sutures (posterior annulorrhaphy after Hetzer). Before these procedures, we attempted to reconstruct the tricuspid valve with a posterior annulorrhaphy alone; however, valve competence was insufficient. A Sebening stitch was necessary to improve the valve competence. Echocardiography showed TR grade 1 at the patient's discharge from hospital and TR grade 1 to 2 at the follow-up, 10 months after the operation. PMID:22419794

[Percutaneously implantable aortic valve: the JenaValve concept evolution].

PubMed

Figulla, Hans R; Ferrari, Markus

2006-10-01

Due to the increasing incidence of severe aortic stenosis in old and multimorbid patients, the percutaneous implantation of aortic valve-carrying stents has become an alternative to the surgical replacement of aortic valves. Starting in 1995, the authors developed a self-expanding stent which transferred the necessary forces for anchoring up to the aorta ascendens-a conception taken over from CoreValve. The further improvement of this idea over the past 11 years has led to a self-expanding, relatively short stent-valve system that is reliably positioned in the cusps of the old aortic valve and holds the old valve like a paper clip, thus transferring the holding forces physiologically. As compared to conventional systems, the sophisticated insertion catheter requires further chronic animal tests so as to represent a true alternative to the conventional surgical procedure.

42 CFR 84.84 - Hand-operated valves; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Hand-operated valves; minimum requirements. 84.84 Section 84.84 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.84 - Hand-operated valves; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Hand-operated valves; minimum requirements. 84.84 Section 84.84 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.84 - Hand-operated valves; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Hand-operated valves; minimum requirements. 84.84 Section 84.84 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.84 - Hand-operated valves; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Hand-operated valves; minimum requirements. 84.84 Section 84.84 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.84 - Hand-operated valves; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Hand-operated valves; minimum requirements. 84.84 Section 84.84 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

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

PubMed

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.

North American trial results at 1 year with the Sorin Freedom SOLO pericardial aortic valve.

PubMed

Heimansohn, David; Roselli, Eric E; Thourani, Vinod H; Wang, Shaohua; Voisine, Pierre; Ye, Jian; Dabir, Reza; Moon, Michael

2016-02-01

A North American prospective, 15-centre Food and Drug Administration (FDA) valve trial was designed to assess the safety and effectiveness of the Freedom SOLO stentless pericardial aortic valve in the treatment of surgical aortic valve disease. Beginning in 2010, 251 patients (mean: 74.7 ± 7.5 years), were recruited in the Freedom SOLO aortic valve trial. One hundred eighty-nine patients have been followed for at least 1 year and are the basis for this review. Preoperatively, 54% of patients had NYHA functional class III or IV symptoms, and the majority of patients had a normal ejection fraction (EF) (median EF = 61%). Concomitant procedures were performed in 61.9% of patients, with coronary artery bypass grafting (CABG) (48.7%) being the most common followed by a MAZE procedure (13.7%). Reoperations were performed in 8.5% of patients in the study. The entire cohort of 251 patients enrolled had 7 deaths prior to 30 days, 2 of which were valve-related (aspiration pneumonia and sudden death) and 5 were not valve-related. There were 11 deaths after 30 days, 1 valve-related (unknown cardiac death) and 10 not valve-related. Five valves were explanted, 3 early (endocarditis, acute insufficiency and possible root dissection) and 2 late (endocarditis). Thirty-day adverse events include arrhythmias requiring permanent pacemaker (4.2%), thromboembolic events (3.7%) and thrombocytopenia (7.4%). One-year follow-up of all 189 patients demonstrated mean gradients for valve sizes 19, 21, 23, 25 and 27 mm of 11.7, 7.8, 6.3, 4.6 and 5.0 mmHg, respectively. Effective orifice areas for the same valve sizes were 1.2, 1.3, 1.6, 1.8 and 1.9 cm(2), respectively. Ninety-six percent of patients (181/189) were in NYHA class I or II at the 1-year follow-up. The Freedom SOLO stentless pericardial aortic valve demonstrated excellent haemodynamics and a good safety profile out to the 1 year of follow-up. © The Author 2015. Published by Oxford University Press on behalf of the European

Early Outcomes for Valve-in-valve Transcatheter Aortic Valve Replacement in Degenerative Freestyle Bioprostheses.

PubMed

Sang, Stephane Leung Wai; Beute, Tyler; Heiser, John; Berkompas, Duane; Fanning, Justin; Merhi, William

2017-11-20

Transcatheter aortic valve replacement (TAVR) is used increasingly to treat bioprosthetic valve failure. A paucity of data exists regarding valve-in-valve (ViV) TAVR in degenerated Freestyle stentless bioprostheses (FSBs). This study sought to evaluate the feasibility and short-term outcomes of ViV TAVR in previously placed FSB. From October 2014 to September 2016, 22 patients at a single institution underwent ViV TAVR with a self-expanding transcatheter valve for a failing FSB. Patient baseline characteristics and clinical outcomes data were collected retrospectively and entered into a dedicated database. The mean patient age was 74 ± 9years, and the mean Society of Thoracic Surgeons' Risk score was 9.0 ± 7.4%. Ten patients presented with acute heart failure requiring urgent intervention. The most common mode of failure of the FSB was regurgitation caused by a flail or malcoapting leaflet. Seventeen (77%) patients had a modified subcoronary implantation, 3 (14%) had a full root replacement, and 2 (9%) had a root inclusion. Device success using a self-expanding transcatheter valve was 95%, all via transfemoral approach. The mean implant depth was 7 ± 3 mm. Thirty-day survival was 100%. No patient had more than mild paravalvular regurgitation at 30days, and the permanent pacemaker rate was 9%. The mean hospital stay after intervention was 5 ± 2days. ViV TAVR using a self-expanding transcatheter valve is safe, feasible, and can be used successfully to treat a failed FSB. Procedural challenges suggest referral to valve centers of excellence. Copyright © 2017 Elsevier Inc. All rights reserved.

Quickly Removable Valve

NASA Technical Reports Server (NTRS)

Robbins, John S.

1988-01-01

Unit removed with minimal disturbance. Valve inlet and outlet ports adjacent to each other on same side of valve body. Ports inserted into special manifold on fluid line. Valve body attached to manifold by four bolts or, alternatively, by toggle clamps. Electromechanical actuator moves in direction parallel to fluid line to open and close valve. When necessary to clean valve, removed simply by opening bolts or toggle clamps. No need to move or separate ports of fluid line. Valve useful where disturbance of fluid line detrimental or where fast maintenance essential - in oil and chemical industries, automotive vehicles, aircraft, and powerplants.

Ball valve extractor

DOEpatents

Herndon, Charles; Brown, Roger A.

2002-01-01

An apparatus and process for removing a ball valve is provided. The ball valve removal tool provides a handle sliding along the length of a shaft. One end of the shaft is secured within an interior cavity of a ball valve while the opposite end of the shaft defines a stop member. By providing a manual sliding force to the handle, the handle impacts the stop member and transmits the force to the ball valve. The direction of the force is along the shaft of the removal tool and disengages the ball valve from the ball valve housing.

Bellows sealed plug valve

DOEpatents

Dukas, Jr., Stephen J.

1990-01-01

A bellows sealed plug valve includes a valve body having an inlet passage and an outlet passage, a valve chamber between the inlet and outlet passages. A valve plug has substantially the same shape as the valve chamber and is rotatably disposed therein. A shaft is movable linearly in response to a signal from a valve actuator. A bellows is sealingly disposed between the valve chamber and the valve actuator and means are located between the bellows and the valve plug for converting linear movement of the shaft connected to the valve actuator to rotational movement of the plug. Various means are disclosed including helical thread mechanism, clevis mechanism and rack and pinion mechanism, all for converting linear motion to rotational motion.

Check valve installation in pilot operated relief valve prevents reverse pressurization

NASA Technical Reports Server (NTRS)

Oswalt, L.

1966-01-01

Two check valves prevent reverse flow through pilot-operated relief valves of differential area piston design. Title valves control pressure flow to ensure that the piston dome pressure is always at least as great as the main relief valve discharge pressure.

Globe stability during simulated vitrectomy with valved and non-valved trocar cannulas

PubMed Central

Abulon, Dina Joy; Charles, Martin; Charles, Daniel E

2015-01-01

Purpose To compare the effects of valved and non-valved cannulas on intraocular pressure (IOP), fluid leakage, and vitreous incarceration during simulated vitrectomy. Methods Three-port pars plana incisions were generated in six rubber eyes using 23-, 25-, and 27-gauge valved and non-valved trocar cannulas. The models were filled with air and IOP was measured. Similar procedures were followed for 36 acrylic eyes filled with saline solution. Vitreous incarceration was analyzed in eleven rabbit and twelve porcine cadaver eyes. Results In the air-filled model, IOP loss was 89%–94% when two non-valved cannulas were unoccupied versus 1%–5% when two valved cannulas were unoccupied. In the fluid-filled model, with non-valved cannulas, IOP dropped while fluid leaked from the open ports. With two open ports, the IOP dropped to 20%–30% of set infusion pressure, regardless of infusion pressure and IOP compensation. The IOP was maintained in valved cannulas when one or two ports were left open, regardless of IOP compensation settings. There was no or minimal fluid leakage through open ports at any infusion pressure. Direct microscopic analysis of rabbit eyes showed that vitreous incarceration was significantly greater with 23-gauge non-valved than valved cannulas (P<0.005), and endoscopy of porcine eyes showed that vitreous incarceration was significantly greater with 23-gauge (P<0.05) and 27-gauge (P<0.05) non-valved cannulas. External observation of rabbit eyes showed vitreous prolapse through non-valved, but not valved, cannulas. Conclusion Valved cannulas surpassed non-valved cannulas in maintaining IOP, preventing fluid leakage, and reducing vitreous incarceration during simulated vitrectomy. PMID:26445520

Transfemoral Implantation of a Fully Repositionable and Retrievable Transcatheter Valve for Noncalcified Pure Aortic Regurgitation.

PubMed

Schofer, Joachim; Nietlispach, Fabian; Bijuklic, Klaudija; Colombo, Antonio; Gatto, Fernando; De Marco, Federico; Mangieri, Antonio; Hansen, Lorenz; Bruschi, Giuseppe; Ruparelia, Neil; Rieß, Friedrich-Christian; Maisano, Franscesco; Latib, Azeem

2015-12-21

This study sought to evaluate the use of the Direct Flow Medical (DFM) transcatheter heart valve (Direct Flow Medical, Santa Rosa, California) for the treatment of noncalcific pure aortic regurgitation (AR). The treatment of noncalcific AR has remained a relative contraindication with transcatheter heart valves due to challenges in anchoring devices in the absence of calcium, concerns of valve embolization, and the high risk of significant residual paravalvular leak. The study population consisted of patients treated for severe noncalcific pure AR with transfemoral implantation of a DFM transcatheter heart valve at 6 European centers. The primary endpoint was the composite endpoint of device success and the secondary endpoint was the composite early safety endpoint (according to the VARC-2 criteria). Eleven high-risk (STS score 8.84 ± 8.9, Logistic EuroSCORE 19.9 ± 7.1) patients (mean age 74.7 ± 12.9 years) were included. Device success was achieved in all patients. In 1 patient, the initial valve prosthesis was retrieved after pull-through, and a second valve was successfully deployed. The early safety endpoint was reached in 91% of the patients, with 1 patient requiring surgical aortic valve replacement secondary to downward dislocation of the prosthesis that was successfully managed with surgical aortic valve replacement. DFM implantation resulted in excellent hemodynamics with none or trivial paravalvular regurgitation in 9 patients and a transprosthetic gradient of 7.7 ± 5.1 mm Hg at 30-day follow up. All patients derived symptomatic benefit following the procedure, with 72% in New York Heart Association functional class I or II. This study reports the feasibility of treating severe noncalcific AR with the Direct Flow prosthesis via the transfemoral route. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Microfluidic sieve valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quake, Stephen R; Marcus, Joshua S; Hansen, Carl L

2015-01-13

Sieve valves for use in microfluidic device are provided. The valves are useful for impeding the flow of particles, such as chromatography beads or cells, in a microfluidic channel while allowing liquid solution to pass through the valve. The valves find particular use in making microfluidic chromatography modules.

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

PubMed

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

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

PubMed

Campante Teles, Rui; Costa, Cátia; Almeida, Manuel; Brito, João; Sondergaard, Lars; Neves, José P; Abecasis, João; M Gabriel, Henrique

2017-03-01

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 for surgery due to advanced age and comorbidities. The patient underwent a first TAVI, with implantation of a Medtronic CoreValve ® , which became dislodged and migrated to the ascending aorta. Due to the previous balloon valvuloplasty, the patient's AS became moderate, and her symptoms improved. After several months, she required another intervention, performed with a St. Jude Portico ® repositionable self-expanding transcatheter aortic valve. There was a good clinical response that was maintained at one-year follow-up. The use of a self-expanding transcatheter bioprosthesis with repositioning features is a solution in cases of valve dislocation to avoid suboptimal positioning of a second implant, especially when the two valves have to be positioned overlapping or partially overlapping each other. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Problem: Heart Valve Stenosis

MedlinePlus

... valve . Learn about the different types of stenosis: Aortic stenosis Tricuspid stenosis Pulmonary stenosis Mitral stenosis Outlook for ... Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - ...

Vacuum breaker valve assembly

DOEpatents

Thompson, J.L.; Upton, H.A.

1999-04-27

Breaker valve assemblies for a simplified boiling water nuclear reactor are described. The breaker valve assembly, in one form, includes a valve body and a breaker valve. The valve body includes an interior chamber, and an inlet passage extends from the chamber and through an inlet opening to facilitate transporting particles from outside of the valve body to the interior chamber. The breaker valve is positioned in the chamber and is configured to substantially seal the inlet opening. Particularly, the breaker valve includes a disk which is sized to cover the inlet opening. The disk is movably coupled to the valve body and is configured to move substantially concentrically with respect to the valve opening between a first position, where the disk completely covers the inlet opening, and a second position, where the disk does not completely cover the inlet opening. 1 fig.

Vacuum breaker valve assembly

DOEpatents

Thompson, Jeffrey L.; Upton, Hubert Allen

1999-04-27

Breaker valve assemblies for a simplified boiling water nuclear reactor are described. The breaker valve assembly, in one form, includes a valve body and a breaker valve. The valve body includes an interior chamber, and an inlet passage extends from the chamber and through an inlet opening to facilitate transporting particles from outside of the valve body to the interior chamber. The breaker valve is positioned in the chamber and is configured to substantially seal the inlet opening. Particularly, the breaker valve includes a disk which is sized to cover the inlet opening. The disk is movably coupled to the valve body and is configured to move substantially concentrically with respect to the valve opening between a first position, where the disk completely covers the inlet opening, and a second position, where the disk does not completely cover the inlet opening.

Zero-leak valve

NASA Technical Reports Server (NTRS)

Macglashan, W. F., Jr.

1980-01-01

Zero-leakage valve has fluid-sealing diaphragm support and flat sievelike sealing surface. Diaphragm-support valve is easy to fabricate and requires minimum maintenance. Potential applications include isolation valve for waste systems and remote air-actuated valve. Device is also useful in controlling flow of liquid fluorine and corrosive fluids at high pressures.

Redo aortic valve surgery versus transcatheter valve-in-valve implantation for failing surgical bioprosthetic valves: consecutive patients in a single-center setting

PubMed Central

Wottke, Michael; Deutsch, Marcus-André; Krane, Markus; Piazza, Nicolo; Lange, Ruediger; Bleiziffer, Sabine

2015-01-01

Background Due to a considerable rise in bioprosthetic as opposed to mechanical valve implantations, an increase of patients presenting with failing bioprosthetic surgical valves in need of a reoperation is to be expected. Redo surgery may pose a high-risk procedure. Transcatheter aortic valve-in-valve implantation is an innovative, less-invasive treatment alternative for these patients. However, a comprehensive evaluation of the outcome of consecutive patients after a valve-in-valve TAVI [transcatheter aortic valve-in-surgical aortic valve (TAV-in-SAV)] as compared to a standard reoperation [surgical aortic valve redo-operation (SAV-in-SAV)] has not yet been performed. The goal of this study was to compare postoperative outcomes after TAV-in-SAV and SAV-in-SAV in a single center setting. Methods All SAV-in-SAV and TAV-in-SAV patients from January 2001 to October 2014 were retrospectively reviewed. Patients with previous mechanical or transcatheter valves, active endocarditis and concomitant cardiac procedures were excluded. Patient characteristics, preoperative data, post-procedural complications, and 30-day mortality were collected from a designated database. Mean values ± SD were calculated for all continuous variables. Counts and percentages were calculated for categorical variables. The Chi-square and Fisher exact tests were used to compare categorical variables. Continuous variables were compared using the t-test for independent samples. A 2-sided P value <0.05 was considered statistically significant. Results A total of 102 patients fulfilled the inclusion criteria, 50 patients (49%) underwent a transcatheter valve-in-valve procedure, while 52 patients (51%) underwent redo-surgery. Patients in the TAV-in-SAV group were significantly older, had a higher mean logistic EuroSCORE and exhibited a lower mean left ventricular ejection fraction than patients in the SAV-in-SAV group (78.1±6.7 vs. 66.2±13.1, P<0.001; 27.4±18.7 vs. 14.4±10, P<0.001; and 49.8±13

Rotary pneumatic valve

DOEpatents

Hardee, Harry C.

1991-01-01

A rotary pneumatic valve which is thrust balanced and the pneumatic pressure developed produces only radial loads on the valve cylinder producing negligible resistance and thus minimal torque on the bearings of the valve. The valve is multiplexed such that at least two complete switching cycles occur for each revolution of the cylinder spindle.

Scissor thrust valve actuator

DOEpatents

DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.

2006-08-29

Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 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...

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

Code of Federal Regulations, 2010 CFR

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...

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 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...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 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...

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 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...

42 CFR 84.120 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Inhalation and exhalation valves; minimum requirements. 84.120 Section 84.120 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

42 CFR 84.120 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Inhalation and exhalation valves; minimum requirements. 84.120 Section 84.120 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

42 CFR 84.120 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Inhalation and exhalation valves; minimum requirements. 84.120 Section 84.120 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

42 CFR 84.120 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Inhalation and exhalation valves; minimum requirements. 84.120 Section 84.120 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

42 CFR 84.120 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Inhalation and exhalation valves; minimum requirements. 84.120 Section 84.120 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

Recellularization of decellularized heart valves: Progress toward the tissue-engineered heart valve

PubMed Central

VeDepo, Mitchell C; Detamore, Michael S; Hopkins, Richard A; Converse, Gabriel L

2017-01-01

The tissue-engineered heart valve portends a new era in the field of valve replacement. Decellularized heart valves are of great interest as a scaffold for the tissue-engineered heart valve due to their naturally bioactive composition, clinical relevance as a stand-alone implant, and partial recellularization in vivo. However, a significant challenge remains in realizing the tissue-engineered heart valve: assuring consistent recellularization of the entire valve leaflets by phenotypically appropriate cells. Many creative strategies have pursued complete biological valve recellularization; however, identifying the optimal recellularization method, including in situ or in vitro recellularization and chemical and/or mechanical conditioning, has proven difficult. Furthermore, while many studies have focused on individual parameters for increasing valve interstitial recellularization, a general understanding of the interacting dynamics is likely necessary to achieve success. Therefore, the purpose of this review is to explore and compare the various processing strategies used for the decellularization and subsequent recellularization of tissue-engineered heart valves. PMID:28890780

Structural valve deterioration in a starr-edwards mitral caged-disk valve prosthesis.

PubMed

Aoyagi, Shigeaki; Tayama, Kei-Ichiro; Okazaki, Teiji; Shintani, Yusuke; Kono, Michitaka; Wada, Kumiko; Kosuga, Ken-Ichi; Mori, Ryusuke; Tanaka, Hiroyuki

2013-01-01

The durability of the Starr-Edwards (SE) mitral caged-disk valve, model 6520, is not clearly known, and structural valve deterioration in the SE disk valve is very rare. Replacement of the SE mitral disk valve was performed in 7 patients 23-40 years after implantation. Macroscopic examination of the removed disk valves showed no structural abnormalities in 3 patients, in whom the disk valves were removed at <26 years after implantation. Localized disk wear was found at the sites where the disk abutted the struts of the cage, in disk valves excised >36 years after implantation in 4 patients. Disk fracture, a longitudinal split in the disk along its circumference at the site of incorporation of the titanium ring, was detected in the valves removed 36 and 40 years after implantation, respectively, and many cracks were also observed on the outflow aspect of the disk removed 40 years after implantation. Disk fracture and localized disk wear were found in the SE mitral disk valves implanted >36 years previously. The present results suggest that SE mitral caged-disk valves implanted >20 years previously should be carefully followed up, and that those implanted >30 years previously should be electively replaced with modern prosthetic valves

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

EPA Pesticide Factsheets

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.

Aortic valve repair leads to a low incidence of valve-related complications.

PubMed

Aicher, Diana; Fries, Roland; Rodionycheva, Svetlana; Schmidt, Kathrin; Langer, Frank; Schäfers, Hans-Joachim

2010-01-01

Aortic valve replacement for aortic regurgitation (AR) has been established as a standard treatment but implies prosthesis-related complications. Aortic valve repair is an alternative approach, but its mid- to long-term results still need to be defined. Over a 12-year period, 640 patients underwent aortic valve repair for regurgitation of a unicuspid (n=21), bicuspid (n=205), tricuspid (n=411) or quadricuspid (n=3) aortic valve. The mechanism of regurgitation involved prolapse (n=469) or retraction (n=20) of the cusps, and dilatation of the root (n=323) or combined pathologies. Treatment consisted of cusp repair (n=529), root repair (n=323) or a combination of both (n=208). The patients were followed clinically and echocardiographically; follow-up was complete in 98.5% (cumulative follow-up: 3035 patient years). Hospital mortality was 3.4% in the total patient cohort and 0.8% for isolated aortic valve repair. The incidences of thrombo-embolism (0.2% per patient per year) and endocarditis (0.16%per patient per year) were low. Freedom from re-operation at 5 and 10 years was 88% and 81% in bicuspid and 97% and 93% in tricuspid aortic valves (p=0.0013). At re-operation, 13 out of 36 valves could be re-repaired. Freedom from valve replacement was 95% and 90% in bicuspid and 97% and 94% in tricuspid aortic valves (p=0.36). Freedom from all valve-related complications at 10 years was 88%. Reconstructive surgery of the aortic valve is feasible with low mortality in many individuals with aortic regurgitation. Freedom from valve-related complications after valve repair seems superior compared to available data on standard aortic valve replacement. Copyright 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Valve

DOEpatents

Cho, Nakwon

1980-01-01

A positive acting valve suitable for operation in a corrosive environment is provided. The valve includes a hollow valve body defining an open-ended bore for receiving two, axially aligned, spaced-apart, cylindrical inserts. One insert, designated the seat insert, terminates inside the valve body in an annular face which lies within plane normal to the axis of the two inserts. An elastomeric O-ring seal is disposed in a groove extending about the annular face. The other insert, designated the wedge insert, terminates inside the valve body in at least two surfaces oppositely inclined with respect to each other and with respect to a plane normal to the axis of the two inserts. An elongated reciprocable gate, movable between the two inserts along a path normal to the axis of the two inserts, has a first flat face portion disposed adjacent and parallel to the annular face of the seat insert. The gate has a second face portion opposite to the first face portion provided with at least two oppositely inclined surfaces for mating with respective inclined surfaces of the wedge insert. An opening is provided through the gate which registers with a flow passage through the two inserts when the valve is open. Interaction of the respective inclined surfaces of the gate and wedge insert act to force the first flat face portion of the gate against the O-ring seal in the seat insert at the limits of gate displacement where it reaches its respective fully open and fully closed positions.

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

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 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...

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

Code of Federal Regulations, 2010 CFR

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...

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

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 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...

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

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 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...

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

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 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...

42 CFR 84.77 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Inhalation and exhalation valves; minimum requirements. 84.77 Section 84.77 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.77 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Inhalation and exhalation valves; minimum requirements. 84.77 Section 84.77 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.77 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Inhalation and exhalation valves; minimum requirements. 84.77 Section 84.77 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.77 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Inhalation and exhalation valves; minimum requirements. 84.77 Section 84.77 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

42 CFR 84.77 - Inhalation and exhalation valves; minimum requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Inhalation and exhalation valves; minimum requirements. 84.77 Section 84.77 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self...

Multi-port valve assembly

DOEpatents

Guggenheim, S. Frederic

1986-01-01

A multi-port fluid valve apparatus is used to control the flow of fluids through a plurality of valves and includes a web, which preferably is a stainless steel endless belt. The belt has an aperture therethrough and is progressed, under motor drive and control, so that its aperture is moved from one valve mechanism to another. Each of the valve mechanisms comprises a pair of valve blocks which are held in fluid-tight relationship against the belt. Each valve block consists of a block having a bore through which the fluid flows, a first seal surrounding the bore and a second seal surrounding the first seal, with the distance between the first and second seals being greater than the size of the belt aperture. In order to open a valve, the motor progresses the belt aperture to where it is aligned with the two bores of a pair of valve blocks, such alignment permitting a flow of the fluid through the valve. The valve is closed by movement of the belt aperture and its replacement, within the pair of valve blocks, by a solid portion of the belt.

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

DOEpatents

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.

Magnetically operated check valve

NASA Technical Reports Server (NTRS)

Morris, Brian G. (Inventor); Bozeman, Richard J., Jr. (Inventor)

1994-01-01

A magnetically operated check valve is disclosed. The valve is comprised of a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

Magnetically operated check valve

NASA Astrophysics Data System (ADS)

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

1994-06-01

A magnetically operated check valve is disclosed. The valve is comprised of a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

46 CFR 154.532 - Valves: Cargo tank MARVS greater than 69 kPa gauge (10 psig).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Valves: Cargo tank MARVS greater than 69 kPa gauge (10... greater than 69 kPa gauge (10 psig). (a) Except connections for tank safety relief valves and except for... on a cargo tank with a MARVS greater than 69 kPa gauge (10 psig) must have, as close to the tank as...

Endoscopic treatment of native lung hyperinflation using endobronchial valves in single-lung transplant patients: a multinational experience.

PubMed

Perch, Michael; Riise, Gerdt C; Hogarth, Kyle; Musani, Ali I; Springmeyer, Steven C; Gonzalez, Xavier; Iversen, Martin

2015-01-01

Hyperinflation of the native lung (NLH) is a known complication to single-lung transplantation for emphysema. The hyperinflation can lead to compression of the graft and cause respiratory failure. Endobronchial valves have been used to block airflow in specific parts of the native lung, reducing the native lung volume and relieving the graft. We report short-term follow-up and safety from 14 single-lung transplant patients with NLH treated with bronchoscopic lung volume reduction using endobronchial valves. Retrospective clinical information related to endobronchial valve treatment was obtained from four centres. All patients were treated with IBV(TM) Valve System (Spiration, Olympus Respiratory America, Redmond, WA, USA). All patients had evidence of severe NLH with mediastinal displacement. A total of 74 IBV valves were placed in 14 patients, with an average of 5.3 (range 2-10). Five patients had two procedures with staged treatment. Eleven patients reported symptom relief, and nine had lung function improvements. There was a significant increase in forced expiratory volume in 1 s of 9% (P = 0.013) and forced vital capacity of 15% (P = 0.034) within the first months after treatment. There were no reported device-related adverse events nor reports of migration. Two patients had pneumothorax. One patient had pneumonia in the location of the valve placement, and another had infection within days. Three other patients were hospitalised with infection 2 months after treatment. Treating NLH with IBV endobronchial valves leads to clinical improvement in the majority of patients, and the treatment has an acceptable safety. © 2014 John Wiley & Sons Ltd.

Which way in? The Necessity of Multiple Approaches to Transcatheter Valve Therapy

PubMed Central

Bleiziffer, S.; Krane, M.; Deutsch, M.A.; Elhmidi, Y.; Piazza, N.; Voss, B.; Lange, R.

2013-01-01

TAVI (transcatheter aortic valve implantation) is a less invasive treatment of the stenotic aortic valve while avoiding midline sternotomy and cardiopulmonary bypass. A crimped biological valve on a self-expanding or balloon-expandable stent is inserted antegradely or retrogradely under fluoroscopy, and deployed on the beating heart. Among the worldwide TAVI programs, many different concepts have been established for the choice of the access site. Whether retrograde or antegrade TAVI should be considered the superior approach is matter of an ongoing debate. The published literature demonstrates safety of all techniques if performed within a dedicated multidisciplinary team. Since there is no data providing evidence if one approach is superior to another, we conclude that an individualized patient-centered decision making process is most beneficial, taking advantage of the complementarity of the different access options. The aim of this article is to give an overview of the current practice of access techniques for transcatheter based valve treatment and to outline the respective special characteristics. PMID:24313647

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

PubMed

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.

Automatic shutoff valve

NASA Technical Reports Server (NTRS)

Hawkins, S. F.; Overbey, C. W.

1980-01-01

Cellulose-sponge disk absorbs incoming water and expands with enough force to shut valve. When water recedes, valve opens by squeezing sponge dry to its original size. This direct mechanical action is considered more reliable than solenoid valve.

Transcatheter aortic valve-in-valve treatment of degenerative stentless supra-annular Freedom Solo valves: A single centre experience.

PubMed

Cockburn, James; Dooley, Maureen; Parker, Jessica; Hill, Andrew; Hutchinson, Nevil; de Belder, Adam; Trivedi, Uday; Hildick-Smith, David

2017-02-15

Redo surgery for degenerative bioprosthetic aortic valves is associated with significant morbidity and mortality. Report results of valve-in-valve therapy (ViV-TAVI) in failed supra-annular stentless Freedom Solo (FS) bioprostheses, which are the highest risk for coronary occlusion. Six patients with FS valves (mean age 78.5 years, 50% males). Five had valvular restenosis (peak gradient 87.2 mm Hg, valve area 0.63 cm 2 ), one had severe regurgitation (AR). Median time to failure was 7 years. Patients were high risk (mean STS/Logistic EuroScore 10.6 15.8, respectively). FS valves ranged from 21 to 25 mm. Successful ViV-TAVI was achieved in 4/6 patients (67%). Of the unsuccessful cases, (patient 1 and 2 of series) patient 1 underwent BAV with simultaneous aortography which revealed left main stem occlusion. The procedure was stopped and the patient went forward for repeat surgery. Patient 2 underwent successful ViV-TAVI with a 26-mm CoreValve with a guide catheter in the left main, but on removal coronary obstruction occurred, necessitating valve snaring into the aorta. Among the successful cases, (patients 3, 4, 5, 6) the TAVIs used were CoreValve Evolut R 23 mm (n = 3), and Lotus 23 mm (n = 1). In the successful cases the peak gradient fell from 83.0 to 38.3 mm Hg. No patient was left with >1+ AR. One patient had a stroke on Day 2, with full neurological recovery. Two patients underwent semi-elective pacing for LBBB and PR >280 ms. ViV-TAVI in stentless Freedom Solo valves is high risk. The risk of coronary occlusion is high. The smallest possible prosthesis (1:1 sizing) should be used, and strategies to protect the coronary vessels must be considered. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Successful use of a left ventricular apical access and closure device for second-generation transapical aortic valve implantation.

PubMed

Conradi, Lenard; Seiffert, Moritz; Shimamura, Kazuo; Schirmer, Johannes; Blankenberg, Stefan; Reichenspurner, Hermann; Diemert, Patrick; Treede, Hendrik

2014-09-01

Transcatheter aortic valve implantation (TAVI) has become routine for the treatment of high-risk patients with aortic stenosis. We assessed safety and feasibility of a left ventricular apical access and closure device combined with second-generation transapical (TA) TAVI transcatheter heart valves (THV). Three elderly, comorbid patients (logEuroSCORE I 13.0-31.1%) received transapical aortic valve implantation (TA-AVI) via the Apica ASC device (Apica Cardiovascular Ltd., Galway, Ireland) using second-generation THV (Medtronic Engager [Medtronic 3F Therapeutics, Santa Ana, California, United States], JenaValve [JenaValve Technology GmbH, Munich, Germany], Symetis Acurate [Symetis S.A., Ecublens, Switzerland]). Access was gained using a non-rib-spreading technique and a novel access and closure device. THV deployment was successful with excellent hemodynamic outcome (no PVL, n = 2; trace PVL, n = 1; mean transvalvular gradients, 5-19 mm Hg) and complete apical hemostasis. No periprocedural major adverse events occurred and Valve Academic Research Consortium-2-defined composite end point of device success was met in all cases. Safety and feasibility of TA-AVI using the ASC device with second-generation THV was demonstrated. Combining latest available technology is a major step toward improved functional outcome and decreased surgical trauma in TA-AVI. Potentially, technical enhancements may eventually pave the way toward a fully percutaneous TA-AVI procedure. Georg Thieme Verlag KG Stuttgart · New York.

Overflow control valve

DOEpatents

Hundal, Rolv; Kessinger, Boyd A.; Parlak, Edward A.

1984-07-24

An overflow control valve for use in a liquid sodium coolant pump tank which valve can be extended to create a seal with the pump tank wall or retracted to break the seal thereby accommodating valve removal. An actuating shaft which controls valve disc position also has cams which bear on roller surfaces to force retraction of a sliding cylinder against spring tension to retract the cylinder from sealing contact with the pump tank.

Aerodynamic Shutoff Valve

NASA Technical Reports Server (NTRS)

Horstman, Raymond H.

1992-01-01

Aerodynamic flow achieved by adding fixed fairings to butterfly valve. When valve fully open, fairings align with butterfly and reduce wake. Butterfly free to turn, so valve can be closed, while fairings remain fixed. Design reduces turbulence in flow of air in internal suction system. Valve aids in development of improved porous-surface boundary-layer control system to reduce aerodynamic drag. Applications primarily aerospace. System adapted to boundary-layer control on high-speed land vehicles.

Mesofluidic two stage digital valve

DOEpatents

Jansen, John F; Love, Lonnie J; Lind, Randall F; Richardson, Bradley S

2013-12-31

A mesofluidic scale digital valve system includes a first mesofluidic scale valve having a valve body including a bore, wherein the valve body is configured to cooperate with a solenoid disposed substantially adjacent to the valve body to translate a poppet carried within the bore. The mesofluidic scale digital valve system also includes a second mesofluidic scale valve disposed substantially perpendicular to the first mesofluidic scale valve. The mesofluidic scale digital valve system further includes a control element in communication with the solenoid, wherein the control element is configured to maintain the solenoid in an energized state for a fixed period of time to provide a desired flow rate through an orifice of the second mesofluidic valve.

Main Oxidizer Valve Design

NASA Technical Reports Server (NTRS)

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.

Slow opening valve. [valve design for shuttle portable oxygen system

NASA Technical Reports Server (NTRS)

Drapeau, D. F. (Inventor)

1984-01-01

A valve control is described having a valve body with an actuator stem and a rotating handle connected to the actuator stem by a differential drive mechanism which, during uniform movement of the handle in one direction, initially opens the valve at a relatively slow rate and, thereafter, complete the valve movement at a substantially faster rate. A series of stop rings are received about the body in frictional abutting relationship and serially rotated by the handle to uniformly resist handle movement independently of the extent of handle movement.

Lightweight Motorized Valve

NASA Technical Reports Server (NTRS)

Gonzalez, R.; Vandewalle, J.

1986-01-01

Redesigned actuator assembly weighs 50 percent less. Isolator valve operated by ac motor instead of usual dc solenoid. Valve weighs only 3 lb (1.4 kg). New valve functions with either two-phase or three-phase power. Developed for isolating fluids in propellant tanks, manifolds, and interconnecting lines of Space Shuttle reaction control and orbital maneuvering subsystems, valve suited to applications in which leakage must be kept to minimum at high pressure differences - in petroleum and chemical processing.

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

PubMed

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.

Cost-Effectiveness of Transcatheter Aortic Valve Replacement With a Self-Expanding Prosthesis Versus Surgical Aortic Valve Replacement.

PubMed

Reynolds, Matthew R; Lei, Yang; Wang, Kaijun; Chinnakondepalli, Khaja; Vilain, Katherine A; Magnuson, Elizabeth A; Galper, Benjamin Z; Meduri, Christopher U; Arnold, Suzanne V; Baron, Suzanne J; Reardon, Michael J; Adams, David H; Popma, Jeffrey J; Cohen, David J

2016-01-05

Previous studies of the cost-effectiveness of transcatheter aortic valve replacement (TAVR) have been based primarily on a single balloon-expandable system. The goal of this study was to evaluate the cost-effectiveness of TAVR with a self-expanding prosthesis compared with surgical aortic valve replacement (SAVR) for patients with severe aortic stenosis and high surgical risk. We performed a formal economic analysis on the basis of individual, patient-level data from the CoreValve U.S. High Risk Pivotal Trial. Empirical data regarding survival and quality of life over 2 years, and medical resource use and hospital costs through 12 months were used to project life expectancy, quality-adjusted life expectancy, and lifetime medical costs in order to estimate the incremental cost-effectiveness of TAVR versus SAVR from a U.S. Relative to SAVR, TAVR reduced initial length of stay an average of 4.4 days, decreased the need for rehabilitation services at discharge, and resulted in superior 1-month quality of life. Index admission and projected lifetime costs were higher with TAVR than with SAVR (differences $11,260 and $17,849 per patient, respectively), whereas TAVR was projected to provide a lifetime gain of 0.32 quality-adjusted life-years ([QALY]; 0.41 LY) with 3% discounting. Lifetime incremental cost-effectiveness ratios were $55,090 per QALY gained and $43,114 per LY gained. Sensitivity analyses indicated that a reduction in the initial cost of TAVR by ∼$1,650 would lead to an incremental cost-effectiveness ratio <$50,000/QALY gained. In a high-risk clinical trial population, TAVR with a self-expanding prosthesis provided meaningful clinical benefits compared with SAVR, with incremental costs considered acceptable by current U.S. With expected modest reductions in the cost of index TAVR admissions, the value of TAVR compared with SAVR in this patient population would become high. (Safety and Efficacy Study of the Medtronic CoreValve System in the Treatment of

Heart Valve Diseases

MedlinePlus

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 ...

Transfemoral aortic valve implantation in severe aortic stenosis patients with prior mitral valve prosthesis

PubMed Central

Sarı, Cenk; Baştuğ, Serdal; Kasapkara, Hacı Ahmet; Durmaz, Tahir; Keleş, Telat; Akçay, Murat; Aslan, Abdullah Nabi; Bayram, Nihal Akar; Bozkurt, Engin

2015-01-01

Introduction Transcatheter aortic valve implantation for severe symptomatic aortic stenosis in patients with a previous mitral valve prosthesis is technically challenging, and pre-procedural comprehensive assessment of these patients before transcatheter aortic valve implantation is vital for an uncomplicated and successful procedure. Aim We want to share our experience with transcatheter aortic valve implantation in patients with a preexisting functional mitral valve prosthesis and describe a series of important technical and pre-procedural details. Material and methods At our center, 135 patients with symptomatic severe aortic stenosis were treated with transcatheter aortic valve implantation. Six of them with a preexisting mitral valve prosthesis received an Edwards SAPIEN XT valve through the transfemoral route. Results Transcatheter aortic valve implantation was performed successfully in all 6 patients without any deformation of the cobalt-chromium/steel stents of the aortic valve bioprosthesis. Also no distortion or malfunction in the mitral valve prosthesis was observed after the procedure. There were no complications during the hospitalization period. Post-procedural echocardiography revealed no or mild aortic paravalvular regurgitation and normal valve function in all the patients. In addition, serial echocardiographic examination demonstrated that both the stability and function of the aortic and mitral prosthetic valves were normal without any deterioration in the gradients and the degree of the regurgitation at long-term follow-ups. Conclusions Our experience confirms that transcatheter aortic valve implantation is technically feasible in patients with previous mitral valve replacement but comprehensive evaluation of patients by multimodal imaging techniques such as transesophageal echocardiography and multislice computed tomography is mandatory for a successful and safe procedure. PMID:26677380

Kangaroo versus porcine aortic valve tissue--valve geometry morphology, tensile strength and calcification potential.

PubMed

Neethling, W M; Papadimitriou, J M; Swarts, E; Hodge, A J

2000-06-01

Valve related factors and patient related factors are responsible for calcification of valvular bioprostheses. Recent studies showed different donor and recipient species have different influences on the total calcification rate of bioprostheses. This study was performed to evaluate and compare Kangaroo aortic valve leaflets with porcine aortic valve leaflets. Experimental design. Prospective study. Setting. Cardio-thoracic experimental research of a university department. Glutaraldehyde-fixed Kangaroo and porcine valve leaflets were evaluated in vitro according to valve geometry (internal diameter and leaflet thickness), morphology (light and electron microscopy) and tensile strength. In vivo evaluation consisted of implantation in a rat model for 8 weeks, Von Kossa stain for calcium and atomic absorption spectrophotometry for total extractable calcium content. Kangaroo valves indicated a smaller internal valve diameter as well as a thinner valve leaflet (p<0.01, ANOVA) at corresponding body weight, less proteoglycan spicules in the fibrosa, increased elasticity (p<0.05) and low calcification potential (p<0.01, confidence interval 95%). Kangaroo aortic valve leaflets have different valvular qualities compared to porcine valve tissue. Kangaroo valve leaflets are significantly superior to porcine valve leaflets as far as calcification is concerned. These results are encouraging and suggest further in vivo evaluation in a larger animal model before clinical application can be considered.

What Is Heart Valve Surgery?

MedlinePlus

... working correctly. Most valve replacements involve the aortic Tricuspid valve and mitral valves. The aortic valve separates ... where it shouldn’t. This is called incompetence, insufficiency or regurgitation. • Prolapse — mitral valve flaps don’t ...

What Is Heart Valve Disease?

MedlinePlus

... and replacing it with a man-made or biological valve. Biological valves are made from pig, cow, or human ... the valve. Man-made valves last longer than biological valves and usually don’t have to be ...

Valve repair in aortic regurgitation without root dilatation--aortic valve repair.

PubMed

Lausberg, H F; Aicher, D; Kissinger, A; Langer, F; Fries, R; Schäfers, H-J

2006-02-01

Aortic valve repair was established in the context of aortic root remodeling. Variable results have been reported for isolated valve repair. We analyzed our experience with isolated valve repair and compared the results with those of aortic root remodeling. Between October 1995 and August 2003, isolated repair of the aortic valve was performed in 83 patients (REP), remodeling of the aortic valve in 175 patients (REMO). The demographics of the two groups were comparable (REP: mean age 54.4 +/- 20.7 yrs, male-female ratio 2.1 : 1; REMO: mean age 60.8 +/- 13.6 yrs, male-female ratio 2.4 : 1; p = ns). In both groups the number of bicuspid valves was comparable (REP: 41 %, REMO: 32 %; p = ns). All patients were followed by echocardiography for a cumulative follow-up of 8204 patient months (mean 32 +/- 23 months). Overall in-hospital mortality was 2.4 % in REP and 4.6 % in REMO ( p = 0.62). Systolic gradients were comparable in both groups (REP: 5.8 +/- 2.2, REMO: 6.5 +/- 3.1 mm Hg, p = 0.09). The mean degree of aortic regurgitation 12 months postoperatively was 0.8 +/- 0.7 after REP and 0.7 +/- 0.7 after REMO ( p = 0.29). Freedom from significant regurgitation (> or = II degrees ) after 5 years was 86 % in REP and 89 % in REMO ( p = 0.17). Freedom from re-operation after 5 years was 94.4 % in REP and 98.2 % in REMO ( p = 0.33). Aortic regurgitation without concomitant root dilatation can be treated effectively by aortic valve repair. The functional results are equivalent to those obtained with valve-preserving root replacement. Aortic valve repair appears to be an alternative to valve replacement in aortic regurgitation.

Mid-term study of transcatheter aortic valve implantation in an Asian population with severe aortic stenosis: two-year Valve Academic Research Consortium-2 outcomes

PubMed Central

Chew, Nicholas; Hon, Jimmy Kim Fatt; Yip, Wei Luen James; Chan, Siew Pang; Poh, Kian-Keong; Kong, William Kok-Fai; Teoh, Kristine Leok Kheng; Yeo, Tiong Cheng; Tan, Huay Cheem; Tay, Edgar Lik Wui

2017-01-01

INTRODUCTION Transcatheter aortic valve implantation (TAVI) is an effective treatment for high-risk or inoperative patients with severe aortic stenosis. Given the unique characteristics of Asian populations, questions regarding mid-term outcomes in Asians undergoing TAVI have yet to be addressed. We evaluated the two-year clinical outcomes of TAVI in an Asian population using Valve Academic Research Consortium-2 definitions. METHODS This prospective study recruited 59 patients from a major academic medical centre in Singapore. The main outcomes were two-year survival rates, peri-procedural complications, symptom improvement, valvular function and assessment of learning curve. RESULTS Mean age was 76.8 years (61.0% male), mean body surface area 1.6 m2 and mean logistic EuroSCORE 18.7%. Survival was 93.2%, 86.0% and 79.1% at 30 days, one year and two years, respectively. At 30 days post TAVI, the rate of stroke was 1.7%, life-threatening bleeding 5.1%, acute kidney injury 25.0%, major vascular complication 5.1%, and new permanent pacemaker implantation 6.8%. 29.3% of TAVI patients were rehospitalised (47.1% cardiovascular-related) within one year. These composite outcomes were measured: device success (93.2%); early safety (79.7%); clinical efficacy (66.1%); and time-related valve safety (84.7%). Univariate analysis found these predictors of two-year all-cause mortality: logistic EuroSCORE (hazard ratio [HR] 1.07; p < 0.001); baseline estimated glomerular filtration rate (HR 0.97; p = 0.048); and acute kidney injury (HR 5.33; p = 0.022). Multivariate analysis identified non-transfemoral TAVI as a predictor of cardiovascular-related two-year mortality (HR 14.64; p = 0.008). CONCLUSION Despite the unique clinical differences in Asian populations, this registry demonstrated favourable mid-term clinical and safety outcomes in Asians undergoing TAVI. PMID:27516113

Mid-term study of transcatheter aortic valve implantation in an Asian population with severe aortic stenosis: two-year Valve Academic Research Consortium-2 outcomes.

PubMed

Chew, Nicholas; Hon, Jimmy Kim Fatt; Yip, Wei Luen James; Chan, Siew Pang; Poh, Kian-Keong; Kong, William Kok-Fai; Teoh, Kristine Leok Kheng; Yeo, Tiong Cheng; Tan, Huay Cheem; Tay, Edgar Lik Wui

2017-09-01

Transcatheter aortic valve implantation (TAVI) is an effective treatment for high-risk or inoperative patients with severe aortic stenosis. Given the unique characteristics of Asian populations, questions regarding mid-term outcomes in Asians undergoing TAVI have yet to be addressed. We evaluated the two-year clinical outcomes of TAVI in an Asian population using Valve Academic Research Consortium-2 definitions. This prospective study recruited 59 patients from a major academic medical centre in Singapore. The main outcomes were two-year survival rates, peri-procedural complications, symptom improvement, valvular function and assessment of learning curve. Mean age was 76.8 years (61.0% male), mean body surface area 1.6 m 2 and mean logistic EuroSCORE 18.7%. Survival was 93.2%, 86.0% and 79.1% at 30 days, one year and two years, respectively. At 30 days post TAVI, the rate of stroke was 1.7%, life-threatening bleeding 5.1%, acute kidney injury 25.0%, major vascular complication 5.1%, and new permanent pacemaker implantation 6.8%. 29.3% of TAVI patients were rehospitalised (47.1% cardiovascular-related) within one year. These composite outcomes were measured: device success (93.2%); early safety (79.7%); clinical efficacy (66.1%); and time-related valve safety (84.7%). Univariate analysis found these predictors of two-year all-cause mortality: logistic EuroSCORE (hazard ratio [HR] 1.07; p < 0.001); baseline estimated glomerular filtration rate (HR 0.97; p = 0.048); and acute kidney injury (HR 5.33; p = 0.022). Multivariate analysis identified non-transfemoral TAVI as a predictor of cardiovascular-related two-year mortality (HR 14.64; p = 0.008). Despite the unique clinical differences in Asian populations, this registry demonstrated favourable mid-term clinical and safety outcomes in Asians undergoing TAVI. Copyright: © Singapore Medical Association

Face-Sealing Butterfly Valve

NASA Technical Reports Server (NTRS)

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.

Transapical JenaValve in a patient with mechanical mitral valve prosthesis.

PubMed

O' Sullivan, Katie E; Casserly, Ivan; Hurley, John

2015-04-01

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.

Modeling the Mitral Valve

NASA Astrophysics Data System (ADS)

Kaiser, Alexander

2016-11-01

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

Magnetically operated check valve

NASA Astrophysics Data System (ADS)

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

1993-03-01

A magnetically operated check valve is disclosed having, in one aspect, a valve body and a movable poppet disposed therein. A magnet attracts the poppet to hold the valve shut until the force of fluid flow through the valve overcomes the magnetic attraction and moves the poppet to an unseated, open position. The poppet and magnet are configured and disposed to trap a magnetically attracted particulate and prevent it from flowing to a valve seating region.

Fast acting check valve

NASA Technical Reports Server (NTRS)

Perkins, Gerald S. (Inventor)

1979-01-01

A check valve which closes more rapidly to prevent wearing of the valve seat and of the valve member that seals thereagainst, including a solenoid or other actuator that aids the normal spring to quickly close the valve at approximately the time when downpath fluid flow would stop, the actuator then being deenergized. The control circuit that operates the actuator can include a pair of pressure sensors sensing pressure both upstream and downstream from the valve seat. Where the valve is utilized to control flow to or from a piston pump, energization of the actuator can be controlled by sensing when the pump piston reaches its extreme of travel.

Double-orifice mitral valve associated with bicuspid aortic valve.

PubMed

Khani, Mohammad; Rohani, Atoosheh

2017-06-01

Double-orifice mitral valve is a rare congenital anomaly that usually does not cause a significant hemodynamic effect. Double-orifice mitral valve and a bicuspid aortic valve were detected in a 54-year-old lady who presented with dyspnea on exertion for one year. This is a rare association. Three-dimensional echocardiography is helpful to determine the type of malformation. The patient had no significant mitral regurgitation or stenosis, but demonstrated moderate aortic stenosis. She is undergoing periodic monitoring.

Valve-sparing aortic root replacement in bicuspid aortic valves: a reasonable option?

PubMed

Aicher, Diana; Langer, Frank; Kissinger, Anke; Lausberg, Henning; Fries, Roland; Schäfers, Hans-Joachim

2004-11-01

Aortic dilatation occurs in many patients with bicuspid aortic valves. We have added root replacement using the remodeling technique originally designed for tricuspid aortic valves to bicuspid aortic valve repair for treatment of the dilated root. We compared the results of remodeling in bicuspid aortic valves with those in tricuspid aortic valves. From October 1995 through January 2004, 60 patients underwent root remodeling for bicuspid aortic valves (group A), and 130 patients underwent root remodeling for tricuspid aortic valves (group B). Correction of cusp prolapse was more often performed in group A (group A, 50/60; group B, 47/130; P < .0001). Transthoracic echocardiography was performed at 1 week, 6 and 12 months, and every year thereafter. Cumulative follow-up was 527 patient-years (mean, 2.9 +/- 2 years). No patient died in group A. Hospital mortality in group B was 5% (5/100; 95% confidence interval,1.6%-11.3%) after elective operations and 10% (3/30; 95% confidence interval, 2.1%-26.5%) after emergency operations. Mean systolic gradients were identical at 1 year (group A, 4.8 +/- 2.1 mm Hg; group B, 4.0 +/- 2 mm Hg) and 5 years (group A, 4.5 +/- 2.3 mm Hg; group B, 3.9 +/- 2.2 mm Hg). Freedom from aortic regurgitation of grade 2 or higher at 5 years was 96% in group A and 83% in group B ( P = .07), and freedom from reoperation at 5 years was 98% in group A and 98% in group B ( P = .73). Valve-sparing aortic replacement with root remodeling can be applied to aortic dilatation and a regurgitant bicuspid aortic valve. Hemodynamic function and valve stability of a repaired bicuspid aortic valve are comparable with those seen in cases of tricuspid anatomy.

Remote actuated valve implant

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.

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.

Valve for fluid control

DOEpatents

Oborny, Michael C.; Paul, Phillip H.; Hencken, Kenneth R.; Frye-Mason, Gregory C.; Manginell, Ronald P.

2001-01-01

A valve for controlling fluid flows. This valve, which includes both an actuation device and a valve body provides: the ability to incorporate both the actuation device and valve into a unitary structure that can be placed onto a microchip, the ability to generate higher actuation pressures and thus control higher fluid pressures than conventional microvalves, and a device that draws only microwatts of power. An electrokinetic pump that converts electric potential to hydraulic force is used to operate, or actuate, the valve.

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

PubMed

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 (P<0.001). No mechanical valve 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.

Solid handling valve

DOEpatents

Williams, William R.

1979-01-01

The present invention is directed to a solids handling valve for use in combination with lock hoppers utilized for conveying pulverized coal to a coal gasifier. The valve comprises a fluid-actuated flow control piston disposed within a housing and provided with a tapered primary seal having a recessed seat on the housing and a radially expandable fluid-actuated secondary seal. The valve seals are highly resistive to corrosion, erosion and abrasion by the solids, liquids, and gases associated with the gasification process so as to minimize valve failure.

VALVE

DOEpatents

Arkelyan, A.M.; Rickard, C.L.

1962-04-17

A gate valve for controlling the flow of fluid in separate concentric ducts or channels by means of a single valve is described. In one position, the valve sealing discs engage opposed sets of concentric ducts leading to the concentric pipes defining the flow channels to block flow therethrough. In another position, the discs are withdrawn from engagement with the opposed ducts and at the same time a bridging section is interposed therebetween to define concentric paths coextensive with and connecting the opposed ducts to facilitate flow therebetween. A wedge block arrangement is employed with each sealing disc to enable it to engage the ducts. The wedge block arrangement also facilitates unobstructcd withdrawal of the discs out of the intervening space between the sets of ducts. (AEC)

Liquid rocket valve components

NASA Technical Reports Server (NTRS)

1973-01-01

A monograph on valves for use with liquid rocket propellant engines is presented. The configurations of the various types of valves are described and illustrated. Design criteria and recommended practices for the various valves are explained. Tables of data are included to show the chief features of valve components in use on operational vehicles.

Transaortic edge-to-edge mitral valve repair for moderate secondary/functional mitral regurgitation in patients undergoing aortic root/valve intervention.

PubMed

Choudhary, Shiv Kumar; Abraham, Atul; Bhoje, Amol; Gharde, Parag; Sahu, Manoj; Talwar, Sachin; Airan, Balram

2017-11-01

The present study evaluates the feasibility, safety, and efficacy of edge-to-edge repair for moderate secondary/functional mitral regurgitation in patients undergoing aortic valve/root interventions. Sixteen patients underwent transaortic edge-to-edge mitral valve repair. Mitral regurgitation was 2+ in 8 patients and 3+ in 6 patients. Two patients in whom cardiac arrest developed preoperatively had severe (4+) mitral regurgitation. Patients underwent operation for severe aortic regurgitation ± aortic root lesions. The mean left ventricular systolic and diastolic diameters were 51.5 ± 12.8 mm and 70.7 ± 10.7 mm, respectively. Left ventricular ejection fraction ranged from 20% to 60%. Primary surgical procedure included Bentall's ± hemiarch replacement in 10 patients, aortic valve replacement in 5 patients, and noncoronary sinus replacement with aortic valve repair in 1 patient. Severity of mitral regurgitation decreased to trivial or zero in 13 patients, 1+ in 2 patients, and 2+ in 1 patient. There were no gradients across the mitral valve in 9 patients, less than 5 mm Hg in 6 patients, and 9 mm Hg in 1 patient. There was no operative mortality. Follow-up ranged from 2 weeks to 54 months. Echocardiography showed trivial or no mitral regurgitation in 12 patients, 1+ in 2 patients, and 2+ in 2 patients. None of the patients had significant mitral stenosis. The mean left ventricular systolic and diastolic diameters decreased to 40.5 ± 10.3 mm and 58.7 ± 11.6 mm, respectively. Ejection fraction also improved slightly (22%-65%). Transaortic edge-to-edge mitral valve repair is a safe and effective technique to abolish secondary/functional mitral regurgitation. However, its impact on overall survival needs to be studied. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Valve assembly for internal combustion engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wakeman, R.J.; Shea, S.F.

1989-09-05

This patent describes an improvement in a valve assembly for an internal combustion engine of the type including a valve having a valve stem, a valve guideway for mounting this valve for reciprocal strokes between opened and seated position, and spring means for biasing the valve into the seated position. The improvement comprising a valve spool of greater cross-sectional diameter as compared to the valve stem, and a valve spool guideway within which the valve spool is movable during the strokes of the valve, an upper surface of the valve spool and a portion of the spool guideway collectively establishingmore » a damper chamber which varies in volume during the valve strokes. a feed passage for introducing oil into the damper chamber, and a bleed passage for discharging oil from the damper chamber. The bleed passages each laterally opening into the valve spool guideway.« less

Transcatheter Aortic Valve Implantation: Experience with the CoreValve Device.

PubMed

Asgar, Anita W; Bonan, Raoul

2012-01-01

The field of transcatheter aortic valve implantation has been rapidly evolving. The Medtronic CoreValve first emerged on the landscape in 2004 with initial first human studies, and it is currently being studied in the Pivotal US trial. This article details the current experience with the self-expanding aortic valve with a focus on clinical results and ongoing challenges. Copyright © 2012 Elsevier Inc. All rights reserved.

Multiple-port valve

DOEpatents

Doody, Thomas J.

1978-08-22

A multiple-port valve assembly is designed to direct flow from a primary conduit into any one of a plurality of secondary conduits as well as to direct a reverse flow. The valve includes two mating hemispherical sockets that rotatably receive a spherical valve plug. The valve plug is attached to the primary conduit and includes diverging passageways from that conduit to a plurality of ports. Each of the ports is alignable wih one or more of a plurality of secondary conduits fitted into one of the hemispherical sockets. The other hemispherical socket includes a slot for the primary conduit such that the conduit's motion along that slot with rotation of the spherical plug about various axes will position the valve-plug ports in respect to the secondary conduits.

Balloon expandable transcatheter aortic valve implantation with or without pre-dilation of the aortic valve - rationale and design of a multicenter registry (EASE-IT).

PubMed

Bramlage, Peter; Strauch, Justus; Schröfel, Holger

2014-11-18

In patients with severe calcific aortic stenosis, balloon aortic valvuloplasty (BAV) is routinely performed in order to pre-dilate the stenosed aortic valve prior to transcatheter aortic valve implantation (TAVI). Although pre-dilation is considered to be essential for the preparation of the valve landing zone, there is no clear evidence to support its clinical value. In contrast, BAV has been suggested to be linked to several complications. Notably, while preliminary evidence has supported the feasibility and safety of TAVI without pre-dilation, larger studies directly comparing the benefit/risk profile of TAVI in the presence and absence of pre-dilation are required. Therefore, a prospective, two-armed, multicenter registry (EASE-IT) was designed to obtain essential data concerning procedural success rates, adverse events, and mortality in a large cohort of patients undergoing transapical (TA)-TAVI using the Edwards SAPIEN 3 balloon expandable heart valves with and without pre-ballooning. Data provided by EASE-IT will be used to assess the relevance of BAV during the TAVI procedure and to investigate associations between patient characteristics and outcomes. Therefore, results obtained from the EASE-IT registry could contribute to reduced rates of TAVI-associated morbidity and mortality in patients with severe, calcific aortic stenosis. ClinicalTrials.gov Identifier: NCT02127580.

Sliding-gate valve

DOEpatents

Usnick, George B.; Ward, Gene T.; Blair, Henry O.; Roberts, James W.; Warner, Terry N.

1979-01-01

This invention is a novel valve of the slidable-gate type. The valve is designed especially for long-term use with highly abrasive slurries. The sealing surfaces of the gate are shielded by the valve seats when the valve is fully open or closed, and the gate-to-seat clearance is swept with an inflowing purge gas while the gate is in transit. A preferred form of the valve includes an annular valve body containing an annular seat assembly defining a flow channel. The seat assembly comprises a first seat ring which is slidably and sealably mounted in the body, and a second seat ring which is tightly fitted in the body. These rings cooperatively define an annular gap which, together with passages in the valve body, forms a guideway extending normal to the channel. A plate-type gate is mounted for reciprocation in the guideway between positions where a portion of the plate closes the channel and where a circular aperture in the gate is in register with the channel. The valve casing includes opposed chambers which extend outwardly from the body along the axis of the guideway to accommodate the end portions of the gate. The chambers are sealed from atmosphere; when the gate is in transit, purge gas is admitted to the chambers and flows inwardly through the gate-to-seat-ring, clearance, minimizing buildup of process solids therein. A shaft reciprocated by an external actuator extends into one of the sealed chambers through a shaft seal and is coupled to an end of the gate. Means are provided for adjusting the clearance between the first seat ring and the gate while the valve is in service.

Solenoid Valve With Self-Compensation

NASA Technical Reports Server (NTRS)

Woeller, Fritz H.; Matsumoto, Yutaka

1987-01-01

New solenoid-operated miniature shutoff valve provides self-compensation of differential pressure forces that cause jamming or insufficient valve closure as in single-seal valves. Dual-seal valve is bidirectional. Valve simultaneously seals both inlet and outlet tubes by pressing single disk of silicone rubber against ends of both.

Study of multiple cycles valves

NASA Technical Reports Server (NTRS)

Wichmann, H.

1973-01-01

A discussion is presented regarding valves which can be cycled repeatedly and are available from industry for application in the inlet system for the Pioneer Venus Probe mass spectrometer. Both solenoid type and latching type valves are considered. The study is divided into two principal areas: (1) preparation of a valve specification reflecting the requirements of the inlet system cyclic valves for the Pioneer Venus Probe mass spectrometer and the submittal of this specification to potential valve suppliers for their response and proposal; (2) preparation of a design layout of an optimum cyclic valve meeting all of the valve specification requirements.

Magnetic Check Valve

NASA Technical Reports Server (NTRS)

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.

Mitral valve replacement with the Hancock stabilized glutaraldehyde valve. Clinical and laboratory evaluation.

PubMed

Buch, W S; Pipkin, R D; Hancock, W D; Fogarty, T J

1975-11-01

From March 1971 through April 1975, one hundred twenty patients underwent mitral valve replacement with a Hancock "stabilized glutaraldehyde process" porcine aortic xenograft. A simultaneous canine experimental series was also carried out. In the clinical series, the early mortality was 8.3%. Actuarial analyses of all patients predicts survival at two years of 81.0% and at four years of 70.0%. The predicted survival for patients without coronary disease or prior prosthetic valve replacement is 87.5% at two years and 77.5% at four years. There were four thromboembolic episodes, a rate of 2.4% per patient-year. None were fatal. No valve failure were noted. Histologic examination and shrink temperature analysis of recovered valves show excellent tissue preservation at 40 months. The data indicate that the Hancock valve is durable, enjoys a low incidence of thromboembolism, and may be the valve of choice for mitral valve replacement.

Anterior mitral valve aneurysm: a rare sequelae of aortic valve endocarditis.

PubMed

Janardhanan, Rajesh; Kamal, Muhammad Umar; Riaz, Irbaz Bin; Smith, M Cristy

2016-03-01

SummaryIn 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. 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. © 2016 The authors.

Transcatheter Mitral Valve Replacement for Native and Failed Bioprosthetic Mitral Valves

PubMed Central

Sarkar, Kunal; Reardon, Michael J.; Little, Stephen H.; Barker, Colin M.; Kleiman, Neal S.

2017-01-01

Transcatheter mitral valve replacement (TMVR) is a novel approach for treatment of severe mitral regurgitation. A number of TMVR devices are currently undergoing feasibility trials using both transseptal and transapical routes for device delivery. Overall experience worldwide is limited to fewer than 200 cases. At present, the 30-day mortality exceeds 30% and is attributable to both patient- and device-related factors. TMVR has been successfully used to treat patients with degenerative mitral stenosis (DMS) as well as failed mitral bioprosthesis and mitral repair using transcatheter mitral valve-in-valve (TMViV)/valve-in-ring (ViR) repair. These patients are currently treated with devices designed for transcatheter aortic valve replacement. Multicenter registries have been initiated to collect outcomes data on patients currently undergoing TMViV/ViR and TMVR for DMS and have confirmed the feasibility of TMVR in these patients. However, the high periprocedural and 30-day event rates underscore the need for further improvements in device design and multicenter randomized studies to delineate the role of these technologies in patients with mitral valve disease. PMID:29743999

Fast acting multiple element valve

DOEpatents

Yang, Jefferson Y. S.; Wada, James M.

1991-01-01

A plurality of slide valve elements having plural axial-spaced annular parts and an internal slide are inserted into a bulkhead in a fluid conduit from a downstream side of the bulkhead, locked in place by a bayonet coupling and set screw, and project through the bulkhead into the upstream conduit. Pneumatic lines connecting the slide valve element actuator to pilot valves are brought out the throat of the valve element to the downstream side. Pilot valves are radially spaced around the exterior of the valve to permit the pneumatic lines to be made identical, thereby to minimize adverse timing tolerances in operation due to pressure variations. Ring manifolds surround the valve adjacent respective pilot valve arrangements to further reduce adverse timing tolerances due to pressure variations, the manifolds being directly connected to the respective pilot valves. Position sensors are provided the valve element slides to signal the precise time at which a slide reaches or passes through a particular point in its stroke to initiate a calibrated timing function.

Conical Seat Shut-Off Valve

NASA Technical Reports Server (NTRS)

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

Fast-acting valve and uses thereof

DOEpatents

Meyer, J.A.

1980-05-16

A very fast acting valve capable of producing a very well-defined plug of gas suitable for filling a theta pinch vacuum vessel is given. The valve requires no springs, instead being stopped mainly by a nonlinear force. Thus, the valve is not subject to bouncing; and the ratio of the size of the valve housing to the size of the valve stem is smaller than it would be if springs were needed to stop the valve stem. Furthermore, the valve can be used for thousands of valve firings with no apparent valve damage.

Fast-acting valve and uses thereof

DOEpatents

Meyer, James A.

1982-01-01

A very fast acting valve capable of producing a very well-defined plug of gas suitable for filling a theta pinch vacuum vessel is given. The valve requires no springs, instead being stopped mainly by a nonlinear force. Thus, the valve is not subject to bouncing; and the ratio of the size of the valve housing to the size of the valve stem is smaller than it would be if springs were needed to stop the valve stem. Furthermore, the valve can be used for thousands of valve firings with no apparent valve damage.

The prognosis of infective endocarditis treated with biological valves versus mechanical valves: A meta-analysis.

PubMed

Tao, Ende; Wan, Li; Wang, WenJun; Luo, YunLong; Zeng, JinFu; Wu, Xia

2017-01-01

Surgery remains the primary form of treatment for infective endocarditis (IE). However, it is not clear what type of prosthetic valve provides a better prognosis. We conducted a meta-analysis to compare the prognosis of infective endocarditis treated with biological valves to cases treated with mechanical valves. Pubmed, Embase and Cochrane databases were searched from January 1960 to November 2016.Randomized controlled trials, retrospective cohorts and prospective studies comparing outcomes between biological valve and mechanical valve management for infective endocarditis were analyzed. The Newcastle-Ottawa Scale(NOS) was used to evaluate the quality of the literature and extracted data, and Stata 12.0 software was used for the meta-analysis. A total of 11 publications were included; 10,754 cases were selected, involving 6776 cases of biological valves and 3,978 cases of mechanical valves. The all-cause mortality risk of the biological valve group was higher than that of the mechanical valve group (HR = 1.22, 95% CI 1.03 to 1.44, P = 0.023), as was early mortality (RR = 1.21, 95% CI 1.02 to 1.43, P = 0.033). The recurrence of endocarditis (HR = 1.75, 95% CI 1.26 to 2.42, P = 0.001), as well as the risk of reoperation (HR = 1.79, 95% CI 1.15 to 2.80, P = 0.010) were more likely to occur in the biological valve group. The incidence of postoperative embolism was less in the biological valve group than in the mechanical valve group, but this difference was not statistically significant (RR = 0.90, 95% CI 0.76 to 1.07, P = 0.245). For patients with prosthetic valve endocarditis (PVE), there was no significant difference in survival rates between the biological valve group and the mechanical valve group (HR = 0.91, 95% CI 0.68 to 1.21, P = 0.520). The results of our meta-analysis suggest that mechanical valves can provide a significantly better prognosis in patients with infective endocarditis. There were significant differences in the clinical features of patients

The prognosis of infective endocarditis treated with biological valves versus mechanical valves: A meta-analysis

PubMed Central

Tao, Ende; Wan, Li; Wang, WenJun; Luo, YunLong; Zeng, JinFu; Wu, Xia

2017-01-01

Objective Surgery remains the primary form of treatment for infective endocarditis (IE). However, it is not clear what type of prosthetic valve provides a better prognosis. We conducted a meta-analysis to compare the prognosis of infective endocarditis treated with biological valves to cases treated with mechanical valves. Methods Pubmed, Embase and Cochrane databases were searched from January 1960 to November 2016.Randomized controlled trials, retrospective cohorts and prospective studies comparing outcomes between biological valve and mechanical valve management for infective endocarditis were analyzed. The Newcastle-Ottawa Scale(NOS) was used to evaluate the quality of the literature and extracted data, and Stata 12.0 software was used for the meta-analysis. Results A total of 11 publications were included; 10,754 cases were selected, involving 6776 cases of biological valves and 3,978 cases of mechanical valves. The all-cause mortality risk of the biological valve group was higher than that of the mechanical valve group (HR = 1.22, 95% CI 1.03 to 1.44, P = 0.023), as was early mortality (RR = 1.21, 95% CI 1.02 to 1.43, P = 0.033). The recurrence of endocarditis (HR = 1.75, 95% CI 1.26 to 2.42, P = 0.001), as well as the risk of reoperation (HR = 1.79, 95% CI 1.15 to 2.80, P = 0.010) were more likely to occur in the biological valve group. The incidence of postoperative embolism was less in the biological valve group than in the mechanical valve group, but this difference was not statistically significant (RR = 0.90, 95% CI 0.76 to 1.07, P = 0.245). For patients with prosthetic valve endocarditis (PVE), there was no significant difference in survival rates between the biological valve group and the mechanical valve group (HR = 0.91, 95% CI 0.68 to 1.21, P = 0.520). Conclusion The results of our meta-analysis suggest that mechanical valves can provide a significantly better prognosis in patients with infective endocarditis. There were significant differences in

Heart valve surgery - series (image)

MedlinePlus

... heart valves are either natural (biologic) or artificial (mechanical). Natural valves are from human donors (cadavers), modified ... artificial valves will require anticoagulation. The advantage of mechanical valves is that they last longer-thus, the ...

Valve Repair or Replacement

MedlinePlus

... called anticoagulants) for the rest of their lives. Biological valves are made from animal tissue (called a ... for valve replacement (called an autograft). Patients with biological valves usually do not need to take blood- ...

Fluid mechanics of heart valves.

PubMed

Yoganathan, Ajit P; He, Zhaoming; Casey Jones, S

2004-01-01

Valvular heart disease is a life-threatening disease that afflicts millions of people worldwide and leads to approximately 250,000 valve repairs and/or replacements each year. Malfunction of a native valve impairs its efficient fluid mechanic/hemodynamic performance. Artificial heart valves have been used since 1960 to replace diseased native valves and have saved millions of lives. Unfortunately, despite four decades of use, these devices are less than ideal and lead to many complications. Many of these complications/problems are directly related to the fluid mechanics associated with the various mechanical and bioprosthetic valve designs. This review focuses on the state-of-the-art experimental and computational fluid mechanics of native and prosthetic heart valves in current clinical use. The fluid dynamic performance characteristics of caged-ball, tilting-disc, bileaflet mechanical valves and porcine and pericardial stented and nonstented bioprostheic valves are reviewed. Other issues related to heart valve performance, such as biomaterials, solid mechanics, tissue mechanics, and durability, are not addressed in this review.

Transapical implantation of a second-generation transcatheter heart valve in patients with noncalcified aortic regurgitation.

PubMed

Seiffert, Moritz; Diemert, Patrick; Koschyk, Dietmar; Schirmer, Johannes; Conradi, Lenard; Schnabel, Renate; Blankenberg, Stefan; Reichenspurner, Hermann; Baldus, Stephan; Treede, Hendrik

2013-06-01

This study sought to report on the feasibility and early results of transcatheter aortic valve implantation employing a second-generation device in a series of patients with pure aortic regurgitation. Efficacy and safety of transcatheter aortic valve implantation in patients with calcific aortic stenosis and high surgical risk has been demonstrated. However, experience with implantation for severe noncalcified aortic regurgitation has been limited due to increased risk for valve dislocation or annular rupture. Five patients (mean age: 66.6 ± 7 years) underwent transapical implantation of a JenaValve (JenaValve Technology GmbH, Munich, Germany) transcatheter heart valve for moderate to severe, noncalcified aortic regurgitation. All patients were considered high risk for surgical aortic valve replacement after evaluation by an interdisciplinary heart team (logistic EuroSCORE [European System for Cardiac Operative Risk Evaluation] range 3.1% to 38.9%). Procedural and acute clinical outcomes were analyzed. Implantation was successful in all cases without relevant remaining aortic regurgitation or signs of stenosis in any of the patients. No major device- or procedure-related adverse events occurred and all 5 patients were alive with improved exercise tolerance at 3-month follow-up. Noncalcified aortic regurgitation continues to be a challenging pathology for transcatheter aortic valve implantation due to the risk for insufficient anchoring of the valve stent within the aortic annulus. This report provides first evidence that the JenaValve prosthesis may be a reasonable option in these specific patients due to its unique stent design, clipping the native aortic valve leaflets, and offering promising early results. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Intelligent Flow Control Valve

NASA Technical Reports Server (NTRS)

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.

How to Make a Heart Valve: From Embryonic Development to Bioengineering of Living Valve Substitutes

PubMed Central

MacGrogan, Donal; Luxán, Guillermo; Driessen-Mol, Anita; Bouten, Carlijn; Baaijens, Frank; de la Pompa, José Luis

2014-01-01

Cardiac valve disease is a significant cause of ill health and death worldwide, and valve replacement remains one of the most common cardiac interventions in high-income economies. Despite major advances in surgical treatment, long-term therapy remains inadequate because none of the current valve substitutes have the potential for remodeling, regeneration, and growth of native structures. Valve development is coordinated by a complex interplay of signaling pathways and environmental cues that cause disease when perturbed. Cardiac valves develop from endocardial cushions that become populated by valve precursor mesenchyme formed by an epithelial–mesenchymal transition (EMT). The mesenchymal precursors, subsequently, undergo directed growth, characterized by cellular compartmentalization and layering of a structured extracellular matrix (ECM). Knowledge gained from research into the development of cardiac valves is driving exploration into valve biomechanics and tissue engineering directed at creating novel valve substitutes endowed with native form and function. PMID:25368013

Maladjustment of programmable ventricular shunt valves by inadvertent exposure to a common hospital device.

PubMed

Fujimura, R; Lober, R; Kamian, K; Kleiner, L

2018-01-01

Programmable ventricular shunt valves are commonly used to treat hydrocephalus. They can be adjusted to allow for varying amounts of cerebrospinal fluid (CSF) flow using an external magnetic programming device, and are susceptible to maladjustment from inadvertent exposure to magnetic fields. We describe the case of a 3-month-old girl treated for hydrocephalus with a programmable Strata TM II valve found at the incorrect setting on multiple occasions during her hospitalization despite frequent reprogramming and surveillance. We found that the Vocera badge, a common hands-free wireless communication system worn by our nursing staff, had a strong enough magnetic field to unintentionally change the shunt setting. The device is worn on the chest bringing it into close proximity to the shunt valve when care providers hold the baby, resulting in the maladjustment. Some commonly used medical devices have a magnetic field strong enough to alter programmable shunt valve settings. Here, we report that the magnetic field from the Vocera hands-free wireless communication system, combined with the worn position, results in shunt maladjustment for the Strata TM II valve. Healthcare facilities using the Vocera badges need to put protocols in place and properly educate staff members to ensure the safety of patients with Strata TM II valves.

30 CFR 250.1630 - Safety-system testing and records.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Sulphur Operations § 250.1630 Safety... components, and the following: (1) Safety relief valves on the natural gas feed system for power plant... source. (2) The following safety devices (excluding electronic pressure transmitters and level sensors...

Locking apparatus for gate valves

DOEpatents

Fabyan, J.; Williams, C.W.

A locking apparatus for fluid operated valves having a piston connected to the valve actuator which moves in response to applied pressure within a cylinder housing having a cylinder head, a catch block is secured to the piston, and the cylinder head incorporates a catch pin. Pressure applied to the cylinder to open the valve moves the piston adjacent to the cylinder head where the catch pin automatically engages the catch block preventing further movement of the piston or premature closure of the valve. Application of pressure to the cylinder to close the valve, retracts the catch pin, allowing the valve to close. Included are one or more selector valves, for selecting pressure application to other apparatus depending on the gate valve position, open or closed, protecting such apparatus from damage due to premature closing caused by pressure loss or operational error.

Transcatheter aortic valve replacement using a self-expanding bioprosthesis in patients with severe aortic stenosis at extreme risk for surgery.

PubMed

Popma, Jeffrey J; Adams, David H; Reardon, Michael J; Yakubov, Steven J; Kleiman, Neal S; Heimansohn, David; Hermiller, James; Hughes, G Chad; Harrison, J Kevin; Coselli, Joseph; Diez, Jose; Kafi, Ali; Schreiber, Theodore; Gleason, Thomas G; Conte, John; Buchbinder, Maurice; Deeb, G Michael; Carabello, Blasé; Serruys, Patrick W; Chenoweth, Sharla; Oh, Jae K

2014-05-20

This study sought to evaluate the safety and efficacy of the CoreValve transcatheter heart valve (THV) for the treatment of severe aortic stenosis in patients at extreme risk for surgery. Untreated severe aortic stenosis is a progressive disease with a poor prognosis. Transcatheter aortic valve replacement (TAVR) with a self-expanding bioprosthesis is a potentially effective therapy. We performed a prospective, multicenter, nonrandomized investigation evaluating the safety and efficacy of self-expanding TAVR in patients with symptomatic severe aortic stenosis with prohibitive risks for surgery. The primary endpoint was a composite of all-cause mortality or major stroke at 12 months, which was compared with a pre-specified objective performance goal (OPG). A total of 41 sites in the United States recruited 506 patients, of whom 489 underwent attempted treatment with the CoreValve THV. The rate of all-cause mortality or major stroke at 12 months was 26.0% (upper 2-sided 95% confidence bound: 29.9%) versus 43.0% with the OPG (p < 0.0001). Individual 30-day and 12-month events included all-cause mortality (8.4% and 24.3%, respectively) and major stroke (2.3% and 4.3%, respectively). Procedural events at 30 days included life-threatening/disabling bleeding (12.7%), major vascular complications (8.2%), and need for permanent pacemaker placement (21.6%). The frequency of moderate or severe paravalvular aortic regurgitation was lower 12 months after self-expanding TAVR (4.2%) than at discharge (10.7%; p = 0.004 for paired analysis). TAVR with a self-expanding bioprosthesis was safe and effective in patients with symptomatic severe aortic stenosis at prohibitive risk for surgical valve replacement. (Safety and Efficacy Study of the Medtronic CoreValve System in the Treatment of Symptomatic Severe Aortic Stenosis in High Risk and Very High Risk Subjects Who Need Aortic Valve Replacement; NCT01240902). Copyright © 2014 American College of Cardiology Foundation. Published by

Long life valve design concepts

NASA Technical Reports Server (NTRS)

Jones, J. R.; Hall, A. H., Jr.

1975-01-01

Valve concept evaluation, final candidate selection, design, manufacture, and demonstration testing of a pneumatically actuated 10-inch hybrid poppet butterfly shutoff valve are presented. Conclusions and recommendations regarding those valve characteristics and features which would serve to guide in the formulation of future valve procurements are discussed. The pertinent design goals were temperature range of plus 200 to minus 423 F, valve inlet pressure 35 psia, actuation pressure 750 psia, main seal leakage 3 x 0.00001 sccs at 35 psia valve inlet pressure, and a storage and operating life of 10 years. The valve was designed to be compatible with RP-1, propane, LH2, LO2, He, and N2.

The Double-Orifice Valve Technique to Treat Tricuspid Valve Incompetence.

PubMed

Hetzer, Roland; Javier, Mariano; Delmo Walter, Eva Maria

2016-01-01

A straightforward tricuspid valve (TV) repair technique was used to treat either moderate or severe functional (normal valve with dilated annulus) or for primary/organic (Ebstein's anomaly, leaflet retraction/tethering and chordal malposition/tethering, with annular dilatation) TV incompetence, and its long-term outcome assessed. A double-orifice valve technique was employed in 91 patients (mean age 52.6 ± 23.2 years; median age 56 years; range: 0.6-82 years) with severe tricuspid regurgitation. Among the patients, three had post-transplant iatrogenic chordal rupture, five had infective endocarditis, 11 had mitral valve insufficiency, 23 had Ebstein's anomaly, and 47 had isolated severe TV incompetence. The basic principle was to reduce the distance between the coapting leaflets, wherein the most mobile leaflet could coapt to the opposite leaflet, by creating two orifices, ensuring valve competence. The TV repair was performed through a median sternotomy or right anterior thoracotomy in the fifth intercostal space under cardiopulmonary bypass. The degree and extent of creating a double-valve orifice was determined by considering the minimal body surface area (BSA)-related acceptable TV diameter. Repair was accomplished by passing pledgeted mattress sutures from the middle of the true anterior annulus to a spot on the opposite septal annulus, located approximately two-thirds of the length of the septal annulus to avoid injury to the bundle of His. The annular apposition divides the TV into a larger anterior and a smaller posterior orifices, enabling valve closure, on both sides. In adults, the diameter of the anterior valve orifice should be 23-25 mm, and the posterior orifice 15-18 mm; thus, the total valve orifice area is 5-6 cm2. In children, the total valve orifice should be a standard deviation of 1.7 mm for a BSA of <1. 0m2, and 1.5 mm for a BSA of >1.0m2. During a mean follow up of 8.7 ± 1.34 years (median 10 years; range: 1.5-25.9 years) there have been no

Compact valve actuation mechanism

NASA Technical Reports Server (NTRS)

Brogdon, James William (Inventor); Gill, David Keith (Inventor)

2000-01-01

A valve actuation device. The device may include a free floating valve bridge movably supported within a cavity in the engine housing. The bridge may be provided with a cavity and an orifice arrangement for pumping gases entrained with lubricating fluid toward the piston stems as the bridge reciprocates back and forth. The device may also include a rocker arm that has a U-shaped cross-sectional shape for receiving at least a portion of the valve bridge, valve stem valve spring and spring retainer therein. The rocker arm may be provided with lubrication passages for directing lubrication to the point wherein it is pivotally affixed to the engine housing.

FLUID MECHANICS OF ARTIFICIAL HEART VALVES

PubMed Central

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

2009-01-01

SUMMARY 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 mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird’s-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10–15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage. PMID:19220329

Fluid mechanics of artificial heart valves.

PubMed

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

2009-02-01

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 mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird's-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10-15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage.

Improved mitral valve coaptation and reduced mitral valve annular size after percutaneous mitral valve repair (PMVR) using the MitraClip system.

PubMed

Patzelt, Johannes; Zhang, Yingying; Magunia, Harry; Ulrich, Miriam; Jorbenadze, Rezo; Droppa, Michal; Zhang, Wenzhong; Lausberg, Henning; Walker, Tobias; Rosenberger, Peter; Seizer, Peter; Gawaz, Meinrad; Langer, Harald F

2017-08-01

Improved mitral valve leaflet coaptation with consecutive reduction of mitral regurgitation (MR) is a central goal of percutaneous mitral valve repair (PMVR) with the MitraClip® system. As influences of PMVR on mitral valve geometry have been suggested before, we examined the effect of the procedure on mitral annular size in relation to procedural outcome. Geometry of the mitral valve annulus was evaluated in 183 patients undergoing PMVR using echocardiography before and after the procedure and at follow-up. Mitral valve annular anterior-posterior (ap) diameter decreased from 34.0 ± 4.3 to 31.3 ± 4.9 mm (P < 0.001), and medio-lateral (ml) diameter from 33.2 ± 4.8 to 32.4 ± 4.9 mm (P < 0.001). Accordingly, we observed an increase in MV leaflet coaptation after PMVR. The reduction of mitral valve ap diameter showed a significant inverse correlation with residual MR. Importantly, the reduction of mitral valve ap diameter persisted at follow-up (31.3 ± 4.9 mm post PMVR, 28.4 ± 5.3 mm at follow-up). This study demonstrates mechanical approximation of both mitral valve annulus edges with improved mitral valve annular coaptation by PMVR using the MitraClip® system, which correlates with residual MR in patients with MR. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Valve technology: A compilation

NASA Technical Reports Server (NTRS)

1971-01-01

A technical compilation on the types, applications and modifications to certain valves is presented. Data cover the following: (1) valves that feature automatic response to stimuli (thermal, electrical, fluid pressure, etc.), (2) modified valves changed by redesign of components to increase initial design effectiveness or give the item versatility beyond its basic design capability, and (3) special purpose valves with limited application as presented, but lending themselves to other uses with minor changes.

The Melody® valve and Ensemble® delivery system for transcatheter pulmonary valve replacement

PubMed Central

McElhinney, Doff B; Hennesen, Jill T

2013-01-01

The Melody® transcatheter pulmonary valve (TPV) is a percutaneous valve system designed for the treatment of obstruction and/or regurgitation of prosthetic conduits placed between the right ventricle and pulmonary arteries in patients with congenital heart disease. In 2000, Melody TPV became the first transcatheter valve implanted in a human; in 2006 it became the first transcatheter valve commercially available anywhere in the world; and in 2010 it was launched as the first commercially available transcatheter valve in the United States. In this review, we present the clinical background against which the Melody valve was developed and implemented, introduce the rationale for and challenges of transcatheter valve technology for this population, outline the history and technical details of its development and use, and summarize currently available data concerning the performance of the device. PMID:23834411

Comparison of acute elastic recoil between the SAPIEN-XT and SAPIEN valves in transfemoral-transcatheter aortic valve replacement.

PubMed

Garg, Aatish; Parashar, Akhil; Agarwal, Shikhar; Aksoy, Olcay; Hammadah, Muhammad; Poddar, Kanhaiya Lal; Puri, Rishi; Svensson, Lars G; Krishnaswamy, Amar; Tuzcu, E Murat; Kapadia, Samir R

2015-02-15

The SAPIEN-XT is a newer generation balloon-expandable valve created of cobalt chromium frame, as opposed to the stainless steel frame used in the older generation SAPIEN valve. We sought to determine if there was difference in acute recoil between the two valves. All patients who underwent transfemoral-transcatheter aortic valve replacement using the SAPIEN-XT valve at the Cleveland Clinic were included. Recoil was measured using biplane cine-angiographic image analysis of valve deployment. Acute recoil was defined as [(valve diameter at maximal balloon inflation) - (valve diameter after deflation)]/valve diameter at maximal balloon inflation (reported as percentage). Patients undergoing SAPIEN valve implantation were used as the comparison group. Among the 23 mm valves, the mean (standard deviation-SD) acute recoil was 2.77% (1.14) for the SAPIEN valve as compared to 3.75% (1.52) for the SAPIEN XT valve (P = 0.04). Among the 26 mm valves, the mean (SD) acute recoil was 2.85% (1.4) for the SAPIEN valve as compared to 4.32% (1.63) for the SAPIEN XT valve (P = 0.01). Multivariable linear regression analysis demonstrated significantly greater adjusted recoil in the SAPIEN XT valves as compared to the SAPIEN valves by 1.43% [(95% CI: 0.69-2.17), P < 0.001]. However, the residual peak gradient was less for SAPIEN XT compared to SAPIEN valves [18.86 mm Hg versus 23.53 mm Hg (P = 0.01)]. Additionally, no difference in paravalvular leak was noted between the two valve types (P = 0.78). The SAPIEN XT valves had significantly greater acute recoil after deployment compared to the SAPIEN valves. Implications of this difference in acute recoil on valve performance need to be investigated in future studies. © 2014 Wiley Periodicals, Inc.

Technical pitfalls and tips for the valve-in-valve procedure

PubMed Central

2017-01-01

Transcatheter aortic valve implantation (TAVI) has emerged as a viable treatment modality for patients with severe aortic valve stenosis and multiple co-morbidities. More recent indications include the use of transcatheter heart valves (THV) to treat degenerated bioprosthetic surgical heart valves (SHV), which are failing due to stenosis or regurgitation. Valve-in-valve (VIV) procedures in the aortic position have been performed with a variety of THV devices, although the balloon-expandable SAPIEN valve platform (Edwards Lifesciences Ltd, Irvine, CA, USA) and self-expandable CoreValve platform (Medtronic Inc., MN, USA) have been used in majority of the patients. VIV treatment is appealing as it is less invasive than conventional surgery but optimal patient selection is vital to avoid complications such as malposition, residual high gradients and coronary obstruction. To minimize the risk of complications, thorough procedural planning is critical. The first step is identification of the degenerated SHV, including its model, size, fluoroscopic appearance. Although label size and stent internal diameter (ID) are provided by the manufacturer, it is important to note the true ID. The true ID is the ID of a SHV after the leaflets are mounted and helps determine the optimal size of THV. The second step is to determine the type and size of the THV. Although this is determined in the majority of the cases by user preference, in certain situations one THV may be more suitable than another. As the procedure is performed under fluoroscopy, the third step is to become familiarized with the fluoroscopic appearance of both the SHV and THV. This helps to determine the landmarks for optimal positioning, which in turn determines the gradients and fixation. The fourth step is to assess the risk of coronary obstruction. This is performed with either aortic root angiography or ECG-gated computerised tomography (CT). Finally, the route of approach must be carefully planned. Once these

Valve stem and packing assembly

DOEpatents

Wordin, John J.

1991-01-01

A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

Valve stem and packing assembly

DOEpatents

Wordin, J.J.

1991-09-03

A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

Self-Rupturing Hermetic Valve

NASA Technical Reports Server (NTRS)

Tucker, Curtis E., Jr.; Sherrit, Stewart

2011-01-01

For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic- activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation. The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow nonhermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations. One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self

Leaving Moderate Tricuspid Valve Regurgitation Alone at the Time of Pulmonary Valve Replacement: A Worthwhile Approach.

PubMed

Kogon, Brian; Mori, Makoto; Alsoufi, Bahaaldin; Kanter, Kirk; Oster, Matt

2015-06-01

Pulmonary valve disruption in patients with tetralogy of Fallot and congenital pulmonary stenosis often results in pulmonary insufficiency, right ventricular dilation, and tricuspid valve regurgitation. Management of functional tricuspid regurgitation at the time of subsequent pulmonary valve replacement remains controversial. Our aims were to (1) analyze tricuspid valve function after pulmonary valve replacement through midterm follow-up and (2) determine the benefits, if any, of concomitant tricuspid annuloplasty. Thirty-five patients with tetralogy of Fallot or congenital pulmonary stenosis were analyzed. All patients had been palliated in childhood by disrupting the pulmonary valve, and all patients had at least moderate tricuspid valve regurgitation at the time of subsequent pulmonary valve replacement. Preoperative and serial postoperative echocardiograms were analyzed. Pulmonary and tricuspid regurgitation, along with right ventricular dilation and dysfunction were scored as 0 (none), 1 (mild), 2 (moderate), and 3 (severe). Right ventricular volume and area were also calculated. Comparisons were made between patients who underwent pulmonary valve replacement alone and those who underwent concomitant tricuspid valve annuloplasty. At 1 month after pulmonary valve replacement, there were significant reductions in pulmonary valve regurgitation (mean 3 vs 0.39, p < 0.0001), tricuspid valve regurgitation (mean 2.33 vs 1.3, p < 0.0001), and in right ventricular dilation, volume, and area. There was no difference in the degree of tricuspid regurgitation 1 month postoperatively between patients who underwent concomitant tricuspid annuloplasty and those who underwent pulmonary valve replacement alone (mean 1.31 vs 1.29, p = 0.81). However, at latest follow-up (mean 7.0 ± 2.8 years), the degree of tricuspid regurgitation was significantly higher in the concomitant annuloplasty group (mean 1.87 vs 1.12, p = 0.005). In patients with at least moderate tricuspid valve

Cryogenic Cam Butterfly Valve

NASA Technical Reports Server (NTRS)

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.

OPERATING PARAMETERS TO MINIMIZE EMISSIONS DURING ROTARY KILN EMERGENCY SAFETY VENT OPENINGS

EPA Science Inventory

Certain designs of hazardous waste incinerator systems include emergency safety vents (ESVs). ESVs (also called dump stacks, vent stacks, emergency by-pass stacks, thermal relief valves, and pressure relief valves) are regarded as true emergency devices. Their purpose is to vent ...

Slide valve apparatus for internal combustion engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, B.A.; McMahan, T.O.

This patent describes an internal combustion engine including a combustion cylinder having an opening at one end thereof, a piston mounted within the cylinder for coaxial reciprocable movement, a driven crankshaft, and a connecting rod connecting the crankshaft to the cylinder for linear reciprocable movement of the piston in response to the rotary movement of the crankshaft, a valve apparatus comprising: (a) a valve chamber extending longitudinally across and in fluid communication with the opening in the cylinder, (b) an intake valve plate having a longitudinal axis mounted within the valve chamber for slidable, reciprocable, longitudinal movement, (c) an exhaustmore » valve plate having a longitudinal axis mounted within the valve chamber alongside the intake valve plate for slidable, reciprocable, longitudinal movement and parallel to the longitudinal axis of the intake valve plate, (d) each of the valve plates having a plurality of longitudinally spaced valve ports therein, the valve ports comprising movable intake valve ports in the intake valve plate and movable exhaust valve ports in the exhaust valve plate, (e) the valve chamber comprising a planar wall on the opposite side of the valve plates from the cylinder opening and having a plurality of fixed valve ports therethrough. The fixed valve ports being equal in number and substantially equal in size and spacing as the movable intake and exhaust valve ports, whereby the movable intake valve ports are adapted to register with their corresponding fixed valve ports when the intake valve plate is in its intake operative position for opening fluid communication between the cylinder and the corresponding fixed valve ports.« less

Three-dimensional printed trileaflet valve conduits using biological hydrogels and human valve interstitial cells.

PubMed

Duan, B; Kapetanovic, E; Hockaday, L A; Butcher, J T

2014-05-01

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, three-dimensional (3-D) bioprinting enables deposition of cells and hydrogels into 3-D constructs with anatomical geometry and heterogeneous mechanical properties. Successful translation of this approach, however, is 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, 3-D printable formulations of hybrid hydrogels are developed, based on methacrylated hyaluronic acid (Me-HA) and methacrylated gelatin (Me-Gel), and used 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 understanding of physiological valve cell interactions and progress towards de novo living valve replacements. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Standardized endpoint definitions for transcatheter aortic valve implantation clinical trials: a consensus report from the Valve Academic Research Consortium†

PubMed Central

Leon, Martin B.; Piazza, Nicolo; Nikolsky, Eugenia; Blackstone, Eugene H.; Cutlip, Donald E.; Kappetein, Arie Pieter; Krucoff, Mitchell W.; Mack, Michael; Mehran, Roxana; Miller, Craig; Morel, Marie-angèle; Petersen, John; Popma, Jeffrey J.; Takkenberg, Johanna J.M.; Vahanian, Alec; van Es, Gerrit-Anne; Vranckx, Pascal; Webb, John G.; Windecker, Stephan; Serruys, Patrick W.

2011-01-01

Objectives To propose standardized consensus definitions for important clinical endpoints in transcatheter aortic valve implantation (TAVI), investigations in an effort to improve the quality of clinical research and to enable meaningful comparisons between clinical trials. To make these consensus definitions accessible to all stakeholders in TAVI clinical research through a peer reviewed publication, on behalf of the public health. Background Transcatheter aortic valve implantation may provide a worthwhile less invasive treatment in many patients with severe aortic stenosis and since its introduction to the medical community in 2002, there has been an explosive growth in procedures. The integration of TAVI into daily clinical practice should be guided by academic activities, which requires a harmonized and structured process for data collection, interpretation, and reporting during well-conducted clinical trials. Methods and results The Valve Academic Research Consortium established an independent collaboration between Academic Research organizations and specialty societies (cardiology and cardiac surgery) in the USA and Europe. Two meetings, in San Francisco, California (September 2009) and in Amsterdam, the Netherlands (December 2009), including key physician experts, and representatives from the US Food and Drug Administration (FDA) and device manufacturers, were focused on creating consistent endpoint definitions and consensus recommendations for implementation in TAVI clinical research programs. Important considerations in developing endpoint definitions included (i) respect for the historical legacy of surgical valve guidelines; (ii) identification of pathophysiological mechanisms associated with clinical events; (iii) emphasis on clinical relevance. Consensus criteria were developed for the following endpoints: mortality, myocardial infarction, stroke, bleeding, acute kidney injury, vascular complications, and prosthetic valve performance. Composite

Lock For Valve Stem

NASA Technical Reports Server (NTRS)

Burley, Richard K.; Guirguis, Kamal S.

1991-01-01

Simple, cheap device locks valve stem so its setting cannot be changed by unauthorized people. Device covers valve stem; cover locked in place with standard padlock. Valve lock made of PVC pipe and packing band. Shears, drill or punch, and forming rod only tools needed.

Björk-Shiley convexoconcave valves: susceptibility artifacts at brain MR imaging and mechanical valve fractures.

PubMed

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

2004-03-01

To assess the relationship between heart valve history and susceptibility artifacts at magnetic resonance (MR) imaging of the brain in patients with Björk-Shiley convexoconcave (BSCC) valves. MR images of the brain were obtained in 58 patients with prosthetic heart valves: 20 patients had BSCC valve replacements, and 38 had other types of heart valves. Two experienced neuroradiologists determined the presence or absence of susceptibility artifacts in a consensus reading. Artifacts were defined as characteristic black spots that were visible on T2*-weighted gradient-echo MR images. The statuses of the 20 explanted BSCC valves-specifically, whether they were intact or had an outlet strut fracture (OSF) or a single-leg fracture (SLF)-had been determined earlier. Number of artifacts seen at brain MR imaging was correlated with explanted valve status, and differences were analyzed with nonparametric statistical tests. Significantly more patients with BSCC valves (17 [85%] of 20 patients) than patients with other types of prosthetic valves (18 [47%] of 38 patients) had susceptibility artifacts at MR imaging (P =.005). BSCC valve OSFs were associated with a significantly higher number of artifacts than were intact BSCC valves (P =.01). No significant relationship between SLF and number of artifacts was observed. Susceptibility artifacts at brain MR imaging are not restricted to patients with BSCC valves. These artifacts can be seen on images obtained in patients with various other types of fractured and intact prosthetic heart valves. Copyright RSNA, 2004

9. BUTTERFLY VALVE CONTROL DIABLO POWERHOUSE. BUTTERFLY VALVES WERE MANUFACTURED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. BUTTERFLY VALVE CONTROL DIABLO POWERHOUSE. BUTTERFLY VALVES WERE MANUFACTURED BY THE PELTON WATER WHEEL COMPANY IN 1931, 1989. - Skagit Power Development, Diablo Powerhouse, On Skagit River, 6.1 miles upstream from Newhalem, Newhalem, Whatcom County, WA

Pregnancy-induced remodeling of heart valves.

PubMed

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.

Self-compensating solenoid valve

NASA Technical Reports Server (NTRS)

Woeller, Fritz H. (Inventor); Matsumoto, Yutaka (Inventor)

1987-01-01

A solenoid valve is described in which both an inlet and an outlet of the valve are sealed when the valve is closed. This double seal compensates for leakage at either the inlet or the outlet by making the other seal more effective in response to the leakage and allows the reversal of the flow direction by simply switching the inlet and outlet connections. The solenoid valve has a valve chamber within the valve body. Inlet and outlet tubes extend through a plate into the chamber. A movable core in the chamber extends into the solenoid coil. The distal end of the core has a silicone rubber plug. Other than when the solenoid is energized, the compressed spring biases the core downward so that the surface of the plug is in sealing engagement with the ends of the tubes. A leak at either end increases the pressure in the chamber, resulting in increased sealing force of the plug.

Concomitant Transapical Transcatheter Valve Implantations: Edwards Sapien Valve for Severe Mitral Regurgitation in a Patient with Failing Mitral Bioprostheses and JenaValve for the Treatment of Pure Aortic Regurgitation.

PubMed

Aydin, Unal; Gul, Mehmet; Aslan, Serkan; Akkaya, Emre; Yildirim, Aydin

2015-04-28

Transcatheter valve implantation is a novel interventional technique, which was developed as an  alternative therapy for surgical aortic valve replacement in inoperable patients with severe aortic stenosis. Despite limited experience in using transcatheter valve implantation for mitral and aortic regurgitation, transapical transcatheter aortic valve implantation and valve-in-valve implantation for degenerated mitral valve bioprosthesis can be performed in high-risk patients who are not candidates for conventional replacement surgery. In this case, we present the simultaneous transcatheter valve implantation via transapical approach for both degenerated bioprosthetic mitral valve with severe regurgitation and pure severe aortic regurgitation.

Bidirectional piston valve

DOEpatents

Fischer, Harry C.

1977-01-01

This invention is a reversing valve having an inlet, an outlet, and an inlet-outlet port. The valve is designed to respond to the introduction of relatively high-pressure fluid at its inlet or, alternatively, of lower-pressure fluid at its inlet-outlet port. The valve includes an axially slidable assembly which is spring-biased to a position where it isolates the inlet and connects the inlet-outlet port to the outlet. The admission of high-pressure fluid to the inlet displaces the slidable assembly to a position where the outlet is isolated and the inlet is connected to the inlet-outlet port. The valve is designed to minimize pressure drops and leakage. It is of a reliable and comparatively simple design.

Anterior urethral valve associated with posterior urethral valves.

PubMed

Kajbafzadeh, A M; Jangouk, P; Ahmadi Yazdi, C

2005-12-01

The association of anterior urethral valve (AUV) with posterior urethral valve (PUV) is rare. A 7-month-old infant was presented at a district hospital with episodes of acute pyelonephritis. He was treated medically and a voiding cystourethrogram (VCUG) confirmed bilateral vesico-urethral reflux. The presence of concomitant AUV and PUV was not recognized. He underwent several surgical procedures, which failed. He had reflux recurrence following two antireflux procedures. He had urinary retention after each operation, which was managed by vesicostomy and perineal urethrostomy. At the age of 3.5 years, he was referred to our paediatric urology clinic. Noticing the AUV and PUV in the past VCUG, the valves were fulgurated. Urodynamic study before and 3 months after valve ablation showed a high voiding pressure. VCUG 6 months following ablation showed no reflux, but several uroflowmetric studies showed a staccato and interrupted pattern. Empirical treatment with an alpha-blocker was started. One year after treatment, a repeat VCUG showed no reflux. Uroflowmetry and urodynamic studies returned to normal. The perineal urethrostomy was closed. The child was asymptomatic after 9 months of follow up.

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

PubMed

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 <60 ml/min/1.73 m2), respectively. Total volume of 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 <0.001), as well as in subgroups with preserved and reduced kidney function. The amount of 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.

Transcatheter aortic valve implantation in patients with bicuspid aortic valve stenosis.

PubMed

Wijesinghe, Namal; Ye, Jian; Rodés-Cabau, Josep; Cheung, Anson; Velianou, James L; Natarajan, Madhu K; Dumont, Eric; Nietlispach, Fabian; Gurvitch, Ronen; Wood, David A; Tay, Edgar; Webb, John G

2010-11-01

We evaluated transcatheter aortic valve implantation (TAVI) in high-risk patients with bicuspid aortic valve (BAV) stenosis. TAVI shows promise in the treatment of severe stenosis of triscupid aortic valves, especially in high-risk patients. However, BAV stenosis has been considered a contraindication to TAVI. Eleven patients (age 52 to 90 years) with symptomatic severe BAV stenosis underwent TAVI at 3 Canadian tertiary hospitals between May 2006 and April 2010. All patients were considered high risk for surgical aortic valve replacement. Edwards-SAPIEN transcatheter heart valves (Edwards Lifesciences, Inc., Irvine, California) were used. Transfemoral or transapical access was selected, depending on the adequacy of femoral access. Access was transfemoral in 7 patients and transapical in 4 patients. There were no intraprocedural complications. Significant symptomatic and hemodynamic improvement was observed in 10 of 11 patients. Baseline aortic valve area of 0.65 ± 0.17 cm(2) and mean transaortic pressure gradient of 41 ± 22.4 mm Hg were improved to 1.45 ± 0.3 cm(2) and 13.4 ± 5.7 mm Hg, respectively. Two patients had moderate perivalvular leaks. At the 30-day follow-up there were 2 deaths due to multisystem failure in 2 transapical patients. In 1 patient an undersized, suboptimally positioned, unstable valve required late conversion to open surgery. TAVI in selected high-risk patients with severe BAV stenosis can be successfully performed with acceptable clinical outcomes but will require further evaluation. Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Systolic Anterior Motion of the Mitral Valve after Mitral Valve Repair

PubMed Central

Sternik, Leonid; Zehr, Kenton J.

2005-01-01

Factors predisposing patients to systolic anterior motion of the mitral valve (SAM) with left ventricular outflow tract (LVOT) obstruction after mitral valve repair are the presence of a myxomatous mitral valve with redundant leaflets, a nondilated hyperdynamic left ventricle, and a short distance between the mitral valve coaptation point and the ventricular septum after repair. From December 1999 through March 2000, we used our surgical method in 6 patients with severely myxomatous regurgitant mitral valves who were at risk of developing SAM. Leaflets were markedly redundant in all 6. Left ventricular function was hyperdynamic in 4 patients and normal in 2. Triangular or quadrangular resection of the midportion of the posterior leaflet and posterior band annuloplasty were performed. To prevent SAM and LVOT obstruction, extra, posteriorly directed, mid-posterior-leaflet secondary chordae tendineae, which would otherwise have been resected, were transferred to the underside of the middle of the mid-anterior leaflet with a small piece of associated valve as an anchoring pledget. This kept the redundant anterior leaflet edge, which extended below the coaptation point, away from the LVOT. No post-repair SAM or LVOT obstruction was observed on intraoperative or discharge echocardiography. All patients had no or trivial residual mitral regurgitation. We conclude that extra chordae tendineae, when available, can be used in mitral valve repair to tether the redundant anterior leaflet and thus prevent it from flipping into the LVOT. This will theoretically prevent SAM and LVOT obstruction in patients with risk factors for SAM. PMID:15902821

Fast closing valve

DOEpatents

Hanson, Clark L.

1984-01-10

A valve is provided for protecting the high vacuum of a particle accelera in the event of air leakage, wherein the valve provides an axially symmetrical passage to avoid disturbance of the partical beam during normal operation, and yet enables very rapid and tight closure of the beam-carrying pipe in the event of air leakage. The valve includes a ball member (30) which can rotate between a first position wherein a bore (32) in the member is aligned with the beam pipe, and a second position out of line with the pipe. A seal member (38) is flexibly sealed to the pipe, and has a seal end which can move tightly against the ball member after the bore has rotated out of line with the pipe, to thereby assure that the seal member does not retard rapid rotation of the ball valve member. The ball valve member can be rapidly rotated by a conductive arm (40) fixed to it and which is rotated by the discharge of a capacitor bank through coils (44, 45) located adjacent to the arm.

Downhole surge valve for earth boring apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, D.W.

1990-05-29

This patent describes a boring tool assembly having an underground percussion mole boring tool powered by a working fluid, the tool being driven through the earth by a rigid drill string pushed by a drilling frame, and a downhole valve assembly fixed between the downhole end of the drill string and the too, the improved downhole valve assembly. It comprises: a valve spool having an open first end, a closed second end and a peripheral sidewall, an axial bore extending partly through the valve spool from the open first end; a radial passage adjacent the closed second and of themore » valve spool, the radial passage extending radially from the valve spool axial bore through the valve spool peripheral sidewall; an axial groove in the peripheral sidewall of the valve spool; a valve body having a first end, a second end and a peripheral sidewall, an axial bore extending through the valve body, the valve spool extending through the valve body axial bore so that the second end of the valve body is adjacent the closed second end of the valve spool, the valve spool being axially moveable within the valve body axial bore; an axial slot; a free-floating key element; a valve housing; and seal means.« less

Update of transcatheter valve treatment

PubMed Central

Liu, Xian-bao; Wang, Jian-an

2013-01-01

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. PMID:23897785

Pressure control valve. [inflating flexible bladders

NASA Technical Reports Server (NTRS)

Lambson, K. H. (Inventor)

1980-01-01

A control valve is provided which is adapted to be connected between a pressure source, such as a vacuum pump, and a pressure vessel so as to control the pressure in the vessel. The valve comprises a housing having a longitudinal bore which is connected between the pump and vessel, and a transversely movable valve body which controls the air flow through an air inlet in the housing. The valve body includes cylindrical and conical shaped portions which cooperate with reciprocally shaped portions of the housing to provide flow control. A filter in the air inlet removes foreign matter from the air. The bottom end of the valve body is screwed into the valve housing control knob formed integrally with the valve body and controls translation of the valve body, and the opening and closing of the valve.

A novel v- silicone vestibular stent: preventing vestibular stenosis and preserving nasal valves.

PubMed

Bassam, Wameedh Al; Bhargava, Deepa; Al-Abri, Rashid

2012-01-01

This report presents a novel style of placing nasal stents. Patients undergoing surgical procedures in the region of nasal vestibule and nasal valves are at risk of developing vestibular stenosis and lifelong problems with the external and internal nasal valves; sequels of the repair. The objective of the report is to demonstrate a simple and successful method of an inverted V- Stent placement to prevent potential complication of vestibular stenosis and nasal valve compromise later in life. Following a fall on a sharp edge of a metallic bed, a sixteen month old child with a deep lacerated nasal wound extending from the collumellar base toward the tip of the nose underwent surgical exploration and repair of the nasal vestibule and nasal cavity. A soft silicone stent fashioned as inverted V was placed bilaterally. The child made a remarkable recovery with no evidence of vestibular stenosis or nasal valve abnormalities. In patients with nasal trauma involving the nasal vestibule and internal and external nasal valves stent placement avoids sequels, adhesions, contractures, synechia vestibular stenosis and fibrosis involving these anatomical structures. The advantages of the described V- stents over the traditional readymade ridged nasal stents, tubing's and composite aural grafts are: a) technical simplicity of use, b) safety, c) less morbidity, d) more comfortable, and e) economical. To our knowledge, this is the first report of such a stent for prevention of vestibular stenosis and preserving nasal valves.

A Novel V- Silicone Vestibular Stent: Preventing Vestibular Stenosis and Preserving Nasal Valves

PubMed Central

Bassam, Wameedh AL; Bhargava, Deepa; Al-Abri, Rashid

2012-01-01

This report presents a novel style of placing nasal stents. Patients undergoing surgical procedures in the region of nasal vestibule and nasal valves are at risk of developing vestibular stenosis and lifelong problems with the external and internal nasal valves; sequels of the repair. The objective of the report is to demonstrate a simple and successful method of an inverted V- Stent placement to prevent potential complication of vestibular stenosis and nasal valve compromise later in life. Following a fall on a sharp edge of a metallic bed, a sixteen month old child with a deep lacerated nasal wound extending from the collumellar base toward the tip of the nose underwent surgical exploration and repair of the nasal vestibule and nasal cavity. A soft silicone stent fashioned as inverted V was placed bilaterally. The child made a remarkable recovery with no evidence of vestibular stenosis or nasal valve abnormalities. In patients with nasal trauma involving the nasal vestibule and internal and external nasal valves stent placement avoids sequels, adhesions, contractures, synechia vestibular stenosis and fibrosis involving these anatomical structures. The advantages of the described V- stents over the traditional readymade ridged nasal stents, tubing’s and composite aural grafts are: a) technical simplicity of use, b) safety, c) less morbidity, d) more comfortable, and e) economical. To our knowledge, this is the first report of such a stent for prevention of vestibular stenosis and preserving nasal valves. PMID:22359729

"Bail out" procedures for malpositioning of aortic valve prosthesis (CoreValve).

PubMed

Vavouranakis, Manolis; Vrachatis, Dimitrios A; Toutouzas, Konstantinos P; Chrysohoou, Christina; Stefanadis, Christodoulos

2010-11-05

Two techniques for correcting malpositioning occurring during percutaneous aortic valve replacement (PAVR) with the CoreValve ReValving™ System are described in this article. The "Removing and Reinserting Technique" was used in 2 patients, in whom the prosthesis was positioned too high. The "Snare Technique" was used in 1 patient, in whom the prosthesis was implanted too low. In all patients the aortic valve prosthesis was successfully re-implanted. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Passively actuated valve

DOEpatents

Modro, S. Michael; Ougouag, Abderrafi M.

2005-09-20

A passively actuated valve for isolating a high pressure zone from a low pressure zone and discontinuing the isolation when the pressure in the high pressure zone drops below a preset threshold. If the pressure in the high pressure zone drops below the preset threshold, the valve opens and allows flow from the high pressure zone to the low pressure zone. The valve remains open allowing pressure equalization and back-flow should a pressure inversion between the two pressure zone occur.

Mitral Valve Prolapse

MedlinePlus

... valve syndrome . What happens during MVP? Watch an animation of mitral valve prolapse When the heart pumps ( ... our brochures Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Heart valve surgery

MedlinePlus

... with an artificial valve (this is called the Ross Procedure). This procedure may be useful for people ... valve that does not close all the way will allow blood to leak backwards. This is called ...

Intraluminal valves: development, function and disease

PubMed Central

Geng, Xin; Cha, Boksik; Mahamud, Md. Riaj

2017-01-01

ABSTRACT The circulatory system consists of the heart, blood vessels and lymphatic vessels, which function in parallel to provide nutrients and remove waste from the body. Vascular function depends on valves, which regulate unidirectional fluid flow against gravitational and pressure gradients. Severe valve disorders can cause mortality and some are associated with severe morbidity. Although cardiac valve defects can be treated by valve replacement surgery, no treatment is currently available for valve disorders of the veins and lymphatics. Thus, a better understanding of valves, their development and the progression of valve disease is warranted. In the past decade, molecules that are important for vascular function in humans have been identified, with mouse studies also providing new insights into valve formation and function. Intriguing similarities have recently emerged between the different types of valves concerning their molecular identity, architecture and development. Shear stress generated by fluid flow has also been shown to regulate endothelial cell identity in valves. Here, we review our current understanding of valve development with an emphasis on its mechanobiology and significance to human health, and highlight unanswered questions and translational opportunities. PMID:29125824

Variable Valve Actuation

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 ismore » 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 the

Space Vehicle Valve System

NASA Technical Reports Server (NTRS)

Kelley, Anthony R. (Inventor); Lindner, Jeffrey L. (Inventor)

2014-01-01

The present invention is a space vehicle valve system which controls the internal pressure of a space vehicle and the flow rate of purged gases at a given internal pressure and aperture site. A plurality of quasi-unique variable dimension peaked valve structures cover the purge apertures on a space vehicle. Interchangeable sheet guards configured to cover valve apertures on the peaked valve structure contain a pressure-activated surface on the inner surface. Sheet guards move outwardly from the peaked valve structure when in structural contact with a purge gas stream flowing through the apertures on the space vehicle. Changing the properties of the sheet guards changes the response of the sheet guards at a given internal pressure, providing control of the flow rate at a given aperture site.

ULTRA HIGH VACUUM VALVE

DOEpatents

Fry, W.A.

1962-05-29

A valve for high vacuum applications such as the CStellarator where chamber pressures as low as 2 x 10/sup -10/ mm Hg are necessary is designed with a line-of-sight path through the valve for visual inspection of the contents of reactants in such chambers. The valve comprises a turnable resilient metal ball having an aperture therethrough, means for selectively turning the ball to rotate the axis of its line-of-sight path, and soft, deformable opposing orifices that are movable relatively toward said ball to seal with opposite ball surfaces upon said movement of said axis of said line-of-sight path. The valve also includes a bellows seal connected between said orifices and internal actuating means that eliminates the requirement for gasketed turnable valve closing stems. (AEC)

All metal valve structure for gas systems

DOEpatents

Baker, Ray W.; Pawlak, Donald A.; Ramey, Alford J.

1984-11-13

A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

All-metal valve structure for gas systems

DOEpatents

Baker, R.W.; Pawlak, D.A.; Ramey, A.J.

1982-06-10

A valve assembly with a resilient metal seat member is disclosed for providing a gas-tight seal in a gas handling system. The valve assembly also includes a valve element for sealing against the valve seat member; and an actuating means for operating the valve element. The valve seat member is a one-piece stainless steel ring having a central valve port and peripheral mounting flange, and an annular corrugation in between. A groove between the first and second ridges serves as a flexure zone during operation of the valve member and thus provides the seating pressure between the inner ridge or valve seat and the valve element. The outer annular ridge has a diameter less than said valve element to limit the seating motion of the valve element, preventing non-elastic deformation of the seat member.

Microblower assisted barometric valve

DOEpatents

Rossabi, Joseph; Hyde, Warren K.; Riha, Brian D.; Jackson, Dennis G.; Sappington, Frank

2005-12-06

A gas exchange apparatus is provided which provides for both passive fluid flow and blower associated fluid flow through a barometric valve. A battery powered blower is provided which allows for operation of the barometric valve during times when the barometric valve would otherwise be closed, and provides for enhanced volume of gas exchange.

Liquid rocket valve assemblies

NASA Technical Reports Server (NTRS)

1973-01-01

The design and operating characteristics of valve assemblies used in liquid propellant rocket engines are discussed. The subjects considered are as follows: (1) valve selection parameters, (2) major design aspects, (3) design integration of valve subassemblies, and (4) assembly of components and functional tests. Information is provided on engine, stage, and spacecraft checkout procedures.

Aerosol penetration through respirator exhalation valves.

PubMed

Bellin, P; Hinds, W C

1990-10-01

Exhalation valves are a critical component of industrial respirators. They are designed to permit minimal inward leakage of air contaminants during inhalation and provide low resistance during exhalation. Under normal conditions, penetration of aerosol through exhalation valves is minimal. The exhalation valve is, however, a vulnerable component of a respirator and under actual working conditions may become dirty or damaged to the point of causing significant leakage. Aerosol penetration was measured for normal exhalation valves and valves compromised by paint or fine copper wires on the valve seat. Penetration increased with increasing wire diameter. A wire 250 microns in diameter allowed greater than 1% penetration into the mask cavity. Dirt or paint accumulated on the exhalation valve allowed a similar level of penetration. Work rate had little effect on observed penetration. Penetration decreased significantly with increasing aerosol particle size. The amount of material on the valve or valve seat necessary for significant (greater than 0.5%) inward leakage in a half-mask respirator could be readily observed by careful inspection of the exhalation valve and its seat in good lighting conditions.

Spool-Valve Pressure-Difference Regulator

NASA Technical Reports Server (NTRS)

Grasso, A. P.

1983-01-01

Valves maintain preset pressure difference between gas flows. Two spool valves connected by shaft move back and forth in response to changes in pressure in oxygen and hydrogen chambers. Spool-valve assembly acts to restore pressures to preset difference. By eliminating diaphragms, pressure exerted directly on external end of spool valve; however, forces and therefore sensitivity of assembly are reduced.

Valve-in-valve using an Edwards Sapien XT into a JenaValve in a patient with a low originating left coronary artery and a heavily calcified aorta.

PubMed

Fujita, Buntaro; Scholtz, Smita; Ensminger, Stephan

2016-04-01

Coronary obstruction during transcatheter aortic valve implantation is a potentially life-threatening complication. Most of the widely used transcatheter heart valves require a certain distance between the basal aortic annular plane and the origins of the coronary arteries. We report the case of a successful valve-in-valve procedure with an Edwards SAPIEN XT valve into a JenaValve as a bail-out procedure in a patient with a low originating left coronary artery and a heavily calcified aorta. © 2015 Wiley Periodicals, Inc.

Mechanisms of mechanical heart valve cavitation: investigation using a tilting disk valve model.

PubMed

He, Z; Xi, B; Zhu, K; Hwang, N H

2001-09-01

The induction of mechanical heart valve (MHV) cavitation was investigated using a 27 mm Medtronic Hall (MH27) tilting disk valve. The MH27 valve was mounted in the mitral position of a simulating pulse flow system, and stroboscopic lighting used to visualize cavitation bubbles on the occluder inflow surface at the instant of valve closure. MHV cavitation was monitored using a digital camera with 0.04 mm/pixel resolution sufficient to render the tiny bubbles clearly visible on the computer monitor screen. Cavitation on MH27 valve was classified as five types according to the time, site and shape of the cavitation bubbles. Valve cavitation occurred at the instant of occluder impact with the valve seat at closing. The impact motion was subdivided into three temporal phases: (i) squeezing flow; (ii) elastic collision; and (iii) leaflet rebound. MHV cavitation caused by vortices was found to be initiated by the squeezing jet and/or by the transvalvular leakage jets. By using a tension wave which swept across the occluder surface immediately upon elastic impact, nuclei in the vortex core were expanded to form cavitation bubbles. Analysis of the shape and location of the cavitation bubbles permitted a better understanding of MHV cavitation mechanisms, based on the fluid dynamics of jet vortex and tension wave propagations.

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

PubMed

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.

Learning curves for transapical transcatheter aortic valve replacement in the PARTNER-I trial: Technical performance, success, and safety.

PubMed

Suri, Rakesh M; Minha, Sa'ar; Alli, Oluseun; Waksman, Ron; Rihal, Charanjit S; Satler, Lowell P; Greason, Kevin L; Torguson, Rebecca; Pichard, Augusto D; Mack, Michael; Svensson, Lars G; Rajeswaran, Jeevanantham; Lowry, Ashley M; Ehrlinger, John; Mick, Stephanie L; Tuzcu, E Murat; Thourani, Vinod H; Makkar, Raj; Holmes, David; Leon, Martin B; Blackstone, Eugene H

2016-09-01

Introduction of hybrid techniques, such as transapical transcatheter aortic valve replacement (TA-TAVR), requires skills that a heart team must master to achieve technical efficiency: the technical performance learning curve. To date, the learning curve for TA-TAVR remains unknown. We therefore evaluated the rate at which technical performance improved, assessed change in occurrence of adverse events in relation to technical performance, and determined whether adverse events after TA-TAVR were linked to acquiring technical performance efficiency (the learning curve). From April 2007 to February 2012, 1100 patients, average age 85.0 ± 6.4 years, underwent TA-TAVR in the PARTNER-I trial. Learning curves were defined by institution-specific patient sequence number using nonlinear mixed modeling. Mean procedure time decreased from 131 to 116 minutes within 30 cases (P = .06) and device success increased to 90% by case 45 (P = .0007). Within 30 days, 354 patients experienced a major adverse event (stroke in 29, death in 96), with possibly decreased complications over time (P ∼ .08). Although longer procedure time was associated with more adverse events (P < .0001), these events were associated with change in patient risk profile, not the technical performance learning curve (P = .8). The learning curve for TA-TAVR was 30 to 45 procedures performed, and technical efficiency was achieved without compromising patient safety. Although fewer patients are now undergoing TAVR via nontransfemoral access, understanding TA-TAVR learning curves and their relationship with outcomes is important as the field moves toward next-generation devices, such as those to replace the mitral valve, delivered via the left ventricular apex. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Bioprinting a cardiac valve.

PubMed

Jana, Soumen; Lerman, Amir

2015-12-01

Heart valve tissue engineering could be a possible solution for the limitations of mechanical and biological prostheses, which are commonly used for heart valve replacement. In tissue engineering, cells are seeded into a 3-dimensional platform, termed the scaffold, to make the engineered tissue construct. However, mimicking the mechanical and spatial heterogeneity of a heart valve structure in a fabricated scaffold with uniform cell distribution is daunting when approached conventionally. Bioprinting is an emerging technique that can produce biological products containing matrix and cells, together or separately with morphological, structural and mechanical diversity. This advance increases the possibility of fabricating the structure of a heart valve in vitro and using it as a functional tissue construct for implantation. This review describes the use of bioprinting technology in heart valve tissue engineering. Copyright © 2015 Elsevier Inc. All rights reserved.

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

PubMed Central

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

Fluid dynamic characterization of a polymeric heart valve prototype (Poli-Valve) tested under continuous and pulsatile flow conditions.

PubMed

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

2015-11-01

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 behavior but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the hemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of 2 groups of newly developed supra-annular, trileaflet prosthetic heart valves made from styrenic block copolymers (SBC): Poli-Valves. 2 types of Poli-Valves made of SBC and differing in polystyrene fraction content were tested under continuous and pulsatile flow conditions as prescribed by ISO 5840 Standard. A pulse duplicator designed ad hoc 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 behavior of the valve. Both types of Poli-Valves met the minimum requirements in terms of regurgitation and EOA as specified by the ISO 5840 Standard. Results were compared with 5 mechanical heart valves (MHVs) and 5 tissue heart valves (THVs), currently available on the market. Based on these results, PHVs based on styrenic block copolymers, as are Poli-Valves, can be considered a promising alternative for heart valve replacement in the near future.

Low energy high pressure miniature screw valve

DOEpatents

Fischer, Gary J [Sandia Park, NM; Spletzer, Barry L [Albuquerque, NM

2006-12-12

A low energy high pressure screw valve having a valve body having an upper portion and a lower portion, said lower portion of said valve body defining an inlet flow passage and an outlet flow passage traversing said valve body to a valve seat, said upper portion of said valve body defining a cavity at said valve seat, a diaphragm restricting flow between said upper portion of said valve body and said lower portion, said diaphragm capable of engaging said valve seat to restrict fluid communication between said inlet passage and said outlet passage, a plunger within said cavity supporting said diaphragm, said plunger being capable of engaging said diaphragm with said valve seat at said inlet and outlet fluid passages, said plunger being in point contact with a drive screw having threads engaged with opposing threads within said upper portion of said valve body such engagement allowing motion of said drive screw within said valve body.

Mitral valve surgery - minimally invasive

MedlinePlus

... flow. Your valve has developed an infection (infectious endocarditis). You have severe mitral valve prolapse that is ... function. Damage to your heart valve from infection (endocarditis). A minimally invasive procedure has many benefits. There ...

49 CFR 195.116 - Valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to the...

Solenoid valve performance characteristics studied

NASA Technical Reports Server (NTRS)

Abe, J. T.; Blackburn, S.

1970-01-01

Current and voltage waveforms of a solenoid coil are recorded as the valve opens and closes. Analysis of the waveforms with respect to time and the phase of the valve cycle accurately describes valve performance.

100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE FOR RAPID-LOAD LIQUID OXYGEN TANK - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Thermostatic Valves Containing Silicone-Oil Actuators

NASA Technical Reports Server (NTRS)

Bhandari, Pradeep; Birur, Gajanana C.; Bame, David P.; Karlmann, Paul B.; Prina, Mauro; Young, William; Fisher, Richard

2009-01-01

Flow-splitting and flow-mixing thermally actuated spool valves have been developed for controlling flows of a heat-transfer fluid in a temperature-regulation system aboard the Mars Science Laboratory (MSL) rover. Valves like these could also be useful in terrestrial temperature-regulation systems, including automobile air-conditioning systems and general refrigeration systems. These valves are required to provide smoother actuation over a wider temperature range than the flow-splitting, thermally actuated spool valves used in the Mars Explorer Rover (MER). Also, whereas the MER valves are unstable (tending to oscillate) in certain transition temperature ranges, these valves are required not to oscillate. The MER valves are actuated by thermal expansion of a wax against spring-loaded piston rods (as in common automotive thermostats). The MSL valves contain similar actuators that utilize thermal expansion of a silicone oil, because silicone-oil actuators were found to afford greater and more nearly linear displacements, needed for smoother actuation, over the required wider temperature range. The MSL valves also feature improved spool designs that reflect greater understanding of fluid dynamics, consideration of pressure drops in valves, and a requirement for balancing of pressures in different flow branches.

[Status of aortic valve reconstruction and Ross operation in aortic valve diseases].

PubMed

Sievers, Hans H

2002-08-01

At first glance the aortic valve is a relative simple valve mechanism connecting the left ventricle and the ascending aorta. Detailed analysis of the different components of the aortic valve including the leaflets and sinuses revealed a complex motion of each part leading to a perfect durable valve mechanism at rest and during exercise. Theoretically, the reconstruction or imitation of these structures in patients with aortic valve disease should lead to optimal results. Prerequisite is the exact knowledge of the important functional characteristics of the aortic valve. The dynamic behavior of the aortic root closely harmonizing with the leaflets not only warrants stress minimizing and valve durability, but also optimizes coronary flow, left ventricular function and aortic impedance. The newly discovered contractile capacity of the leaflets and the root components are important for tuning the dynamics. Isolated reconstruction of the aortic valve such as decalcification, commissurotomy, plication of ring or leaflets of a tricuspid aortic valve and cusp extension are seldom indicated in contrast to the reconstruction of the bicuspid insufficient valve. Proper indication and skilled techniques lead to excellent hemodynamic and clinical intermediate-term result up to 7 years after reconstruction. Latest follow-up revealed a mean aortic insufficiency of 0.7, maximal pressure gradient of 11.4 +/- 8.5 mm Hg with zero hospital or late mortality, reoperation or thromboembolic events in 22 patients. The reconstructive techniques for aortic root aneurysm and/or type A dissection according to David or Yacoub have become routine procedures in the last 10 years. The hemodynamic and clinical results are excellent with low reoperation rate and very low risk of thromboembolism. Generally, a maximal diameter of the root of 5 cm is indicative for performing the operation. In patients with Marfan's syndrome the reconstruction should be advanced even with smaller diameters especially

Evaluating the Performance of the NASA LaRC CMF Motion Base Safety Devices

NASA Technical Reports Server (NTRS)

Gupton, Lawrence E.; Bryant, Richard B., Jr.; Carrelli, David J.

2006-01-01

This paper describes the initial measured performance results of the previously documented NASA Langley Research Center (LaRC) Cockpit Motion Facility (CMF) motion base hardware safety devices. These safety systems are required to prevent excessive accelerations that could injure personnel and damage simulator cockpits or the motion base structure. Excessive accelerations may be caused by erroneous commands or hardware failures driving an actuator to the end of its travel at high velocity, stepping a servo valve, or instantly reversing servo direction. Such commands may result from single order failures of electrical or hydraulic components within the control system itself, or from aggressive or improper cueing commands from the host simulation computer. The safety systems must mitigate these high acceleration events while minimizing the negative performance impacts. The system accomplishes this by controlling the rate of change of valve signals to limit excessive commanded accelerations. It also aids hydraulic cushion performance by limiting valve command authority as the actuator approaches its end of travel. The design takes advantage of inherent motion base hydraulic characteristics to implement all safety features using hardware only solutions.

Options for Heart Valve Replacement

MedlinePlus

... which may include human or animal donor tissue) Ross Procedure — “Borrowing” your healthy valve and moving it ... Considerations for Surgery Medications Valve Repair Valve Replacement - Ross Procedure - Newer Surgery Options - What is TAVR? - Types ...

Damage-Free Relief-Valve Disassembly

NASA Technical Reports Server (NTRS)

Haselmaier, H.

1986-01-01

Tool safely disassembles relief valves without damage to sensitive parts. Relief-valve disassembly tool used to extract valve nozzle from its housing. Holding device on tool grops nozzle. When user strikes hammer against impact disk, holding device pulls nozzle from press fit. Previously, nozzle dislodged by striking spindle above it, but practice often damaged retaining screw. New tool removes nozzle directly. With minor modifications, tool adapted to valves from different manufacturers.

Transcatheter mitral valve repair in osteogenesis imperfecta associated mitral valve regurgitation.

PubMed

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.

Aortic valve replacement for papillary fibroelastoma.

PubMed

Arikan, Ali Ahmet; Omay, Oğuz; Aydın, Fatih; Kanko, Muhip; Gür, Sibel; Derviş, Emir; Yılmaz, Cansu Eda; Müezzinoğlu, Bahar

2017-06-01

Surgery is indicated for symptomatic patients with papillary fibroelastomas (PFE) on the aortic valve. The valve is commonly spared during tumor excision. Rarely, aortic valve replacement (AVR) is needed. We present a case requiring AVR for an aortic valve PFE and review the literature to determine the risk factors for failure of aortic valve-sparing techniques in patients with PFE. © 2017 Wiley Periodicals, Inc.

46 CFR 56.20-9 - Valve construction.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) motion of the handwheel or operating lever as seen by one facing the end of the valve stem. Each gate, globe, and angle valve must generally be of the rising-stem type, preferably with the stem threads... nonrising-stem valve will be acceptable. Each nonrising-stem valve, lever-operated valve, or other valve...

46 CFR 56.20-9 - Valve construction.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) motion of the handwheel or operating lever as seen by one facing the end of the valve stem. Each gate, globe, and angle valve must generally be of the rising-stem type, preferably with the stem threads... nonrising-stem valve will be acceptable. Each nonrising-stem valve, lever-operated valve, or other valve...

46 CFR 56.20-9 - Valve construction.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) motion of the handwheel or operating lever as seen by one facing the end of the valve stem. Each gate, globe, and angle valve must generally be of the rising-stem type, preferably with the stem threads... nonrising-stem valve will be acceptable. Each nonrising-stem valve, lever-operated valve, or other valve...

46 CFR 56.20-9 - Valve construction.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) motion of the handwheel or operating lever as seen by one facing the end of the valve stem. Each gate, globe, and angle valve must generally be of the rising-stem type, preferably with the stem threads... nonrising-stem valve will be acceptable. Each nonrising-stem valve, lever-operated valve, or other valve...

Inverse spin-valve effect in nanoscale Si-based spin-valve devices

NASA Astrophysics Data System (ADS)

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.

Safety and cost-effectiveness of bridge therapies for invasive dental procedures in patients with mechanical heart valves.

PubMed

Won, Ki-Bum; Lee, Seung-Hyun; Chang, Hyuk-Jae; Shim, Chi-Young; Hong, Gue-Ru; Ha, Jong-Won; Chung, Namsik

2014-07-01

Bridge anticoagulation therapy is mostly utilized in patients with mechanical heart valves (MHV) receiving warfarin therapy during invasive dental procedures because of the risk of excessive bleeding related to highly vascular supporting dental structures. Bridge therapy using low molecular weight heparin may be an attractive option for invasive dental procedures; however, its safety and cost-effectiveness compared with unfractionated heparin (UFH) is uncertain. This study investigated the safety and cost-effectiveness of enoxaparin in comparison to UFH for bridge therapy in 165 consecutive patients (57±11 years, 35% men) with MHV who underwent invasive dental procedures. This study included 75 patients treated with UFH-based bridge therapy (45%) and 90 patients treated with enoxaparin-based bridge therapy (55%). The bleeding risk of dental procedures and the incidence of clinical adverse outcomes were not significantly different between the UFH group and the enoxaparin group. However, total medical costs were significantly lower in the enoxaparin group than in the UFH group (p<0.001). After multivariate adjustment, old age (≥65 years) was significantly associated with an increased risk of total bleeding independent of bridging methods (odds ratio, 2.51; 95% confidence interval, 1.15-5.48; p=0.022). Enoxaparin-based bridge therapy (β=-0.694, p<0.001) and major bleeding (β=0.296, p=0.045) were significantly associated with the medical costs within 30 days after dental procedures. Considering the benefit of enoxaparin in cost-effectiveness, enoxaparin may be more efficient than UFH for bridge therapy in patients with MHV who required invasive dental procedures.

Valve malfunction detection apparatus

NASA Astrophysics Data System (ADS)

Burley, Richard K.

1993-07-01

A detection system is provided for sensing a malfunction of a valve having an outlet connected to an end of a first pipe through which pressurized fluid may be flowed in a downstream direction away from the valve. The system includes a bypass pipe connected at its opposite ends to the first pipe and operative to bypass a portion of the fluid flow therethrough around a predetermined section thereof. A housing is interiorly divided by a flexible diaphragm into first and second opposite chambers which are respectively communicated with the first pipe section and the bypass pipe, the diaphragm being spring-biased toward the second chamber. The diaphragm housing cooperates with check valves and orifices connected in the two pipes to create and maintain a negative pressure in the first pipe section in response to closure of the valve during pressurized flow through the first pipe. A pressure switch senses the negative pressure and transmits a signal indicative thereof to a computer. Upon cessation of the signal while the valve is still closed, the computer responsively generates a signal indicating that the valve, or another portion of the detection system, is leaking.

Valve malfunction detection apparatus

NASA Technical Reports Server (NTRS)

Burley, Richard K. (Inventor)

1993-01-01

A detection system is provided for sensing a malfunction of a valve having an outlet connected to an end of a first pipe through which pressurized fluid may be flowed in a downstream direction away from the valve. The system includes a bypass pipe connected at its opposite ends to the first pipe and operative to bypass a portion of the fluid flow therethrough around a predetermined section thereof. A housing is interiorly divided by a flexible diaphragm into first and second opposite chambers which are respectively communicated with the first pipe section and the bypass pipe, the diaphragm being spring-biased toward the second chamber. The diaphragm housing cooperates with check valves and orifices connected in the two pipes to create and maintain a negative pressure in the first pipe section in response to closure of the valve during pressurized flow through the first pipe. A pressure switch senses the negative pressure and transmits a signal indicative thereof to a computer. Upon cessation of the signal while the valve is still closed, the computer responsively generates a signal indicating that the valve, or another portion of the detection system, is leaking.

Electro-Mechanical Coaxial Valve

NASA Technical Reports Server (NTRS)

Patterson, Paul R (Inventor)

2004-01-01

Coaxial valves usually contain only one moving part. It has not been easy, then, to provide for electric motor actuation. Many actuators being proposed involve designs which lead to bulky packages. The key facing those improving coaxial valves is the provision of suitable linear actuation. The valve herein indudes a valve housing with a flow channel there-through. Arranged in the flow channel is a closing body. In alignment with the closing body is a ball screw actuator which includes a ball nut and a cylindrical screw. The ball nut sounds a threaded portion of the cylindrical screw. The cylindrical screw is provided with a passageway there-through through which fluid flows. The cylindrical screw is disposed in the flow channel to become a control tube adapted to move toward and away from the valve seat. To rotate the ball nut an actuating drive is employed driven by a stepper motor.

Valve for controlling solids flow

DOEpatents

Feldman, David K.

1980-01-01

A fluidized solids control valve is disclosed that is particularly well adapted for use with a flow of coal or char that includes both large particles and fines. The particles may or may not be fluidized at various times during the operation. The valve includes a tubular body that terminates in a valve seat covered by a normally closed closure plate. The valve body at the seat and the closure plate is provided with aligned longitudinal slots that receive a pivotally supported key plate. The key plate is positionable by an operator in inserted, intermediate and retracted positions respecting the longitudinal slot in the valve body. The key plate normally closes the slot within the closure plate but is shaped and aligned obliquely to the longitudinal slot within the valve body to provide progressively increasing slot openings between the inserted and retracted positions. Transfer members are provided between the operator, key plate and closure plate to move the closure plate into an open position only when the key plate is retracted from the longitudinal slot within the valve body.

Optothermally actuated capillary burst valve

NASA Astrophysics Data System (ADS)

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.

SLM Produced Hermetically Sealed Isolation Valve

NASA Technical Reports Server (NTRS)

Richard, James

2014-01-01

Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic-driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic-based valve.

SLM Produced Hermetically Sealed Isolation Valve

NASA Technical Reports Server (NTRS)

Richard, James A.

2014-01-01

Marshall Space Flight Center (MSFC) has developed a valve concept to replace traditional pyrotechnic driven isolation valves. This paper will describe the valve design and development process. The valve design uses a stem/wedge to support a disk inside the valve. That disk hermetically seals the pressurized fluids. A release mechanism holds the stem/wedge and a large spring in place. When required to open, a solenoid is energized and pulls the release mechanism allowing the spring to pull the stem/wedge away from the disk. Now the disk is unsupported and the pressure ruptures the disk allowing flow to the outlet of the valve. This paper will provide details of this design, describe the development testing, and show the results from the valve level tests performed. Also, a trade study is presented to show the advantages of this design to a conventional pyrotechnic based valve.

Semi-active compressor valve

DOEpatents

Brun, Klaus; Gernentz, Ryan S.

2010-07-27

A method and system for fine-tuning the motion of suction or discharge valves associated with cylinders of a reciprocating gas compressor, such as the large compressors used for natural gas transmission. The valve's primary driving force is conventional, but the valve also uses an electromagnetic coil to sense position of the plate (or other plugging element) and to provide an opposing force prior to impact.

Mitral valve-sparing procedures and prosthetic heart valve failure: A case report

PubMed Central

Khan, Nasir A; Butany, Jagdish; Leong, Shaun W; Rao, Vivek; Cusimano, Robert J; Ross, Heather J

2009-01-01

Prosthetic heart valve dysfunction due to thrombus or pannus formation can be a life-threatening complication. The present report describes a 47-year-old woman who developed valvular cardiomyopathy after chorda-sparing mitral valve replacement, and subsequently underwent heart transplantation for progressive heart failure. The explanted mitral valve prosthesis showed significant thrombus and pannus leading to reduced leaflet mobility and valvular stenosis. The present report illustrates the role of the subvalvular apparatus and pannus in prosthesis dysfunction. PMID:19279993

Liquid rocket pressure regulators, relief valves, check valves, burst disks, and explosive valves. [design techniques and practices

NASA Technical Reports Server (NTRS)

1973-01-01

The development of and operational programs for effective use in design are presented for liquid rocket pressure regulators, relief valves, check valves, burst disks, and explosive valves. A review of the total design problem is presented, and design elements are identified which are involved in successful design. Current technology pertaining to these elements is also described. Design criteria are presented which state what rule or standard must be imposed on each essential design element to assure successful design. These criteria serve as a checklist of rules for a project manager to use in guiding a design or in assessing its adequacy. Recommended practices are included which state how to satisfy each of the criteria.

Simple Check Valves for Microfluidic Devices

NASA Technical Reports Server (NTRS)

Willis, Peter A.; Greer, Harold F.; Smith, J. Anthony

2010-01-01

A simple design concept for check valves has been adopted for microfluidic devices that consist mostly of (1) deformable fluorocarbon polymer membranes sandwiched between (2) borosilicate float glass wafers into which channels, valve seats, and holes have been etched. The first microfluidic devices in which these check valves are intended to be used are micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. In this application, it will be necessary to store some liquid samples in reservoirs in the devices for subsequent laboratory analysis, and check valves are needed to prevent cross-contamination of the samples. The simple check-valve design concept is also applicable to other microfluidic devices and to fluidic devices in general. These check valves are simplified microscopic versions of conventional rubber- flap check valves that are parts of numerous industrial and consumer products. These check valves are fabricated, not as separate components, but as integral parts of microfluidic devices. A check valve according to this concept consists of suitably shaped portions of a deformable membrane and the two glass wafers between which the membrane is sandwiched (see figure). The valve flap is formed by making an approximately semicircular cut in the membrane. The flap is centered over a hole in the lower glass wafer, through which hole the liquid in question is intended to flow upward into a wider hole, channel, or reservoir in the upper glass wafer. The radius of the cut exceeds the radius of the hole by an amount large enough to prevent settling of the flap into the hole. As in a conventional rubber-flap check valve, back pressure in the liquid pushes the flap against the valve seat (in this case, the valve seat is the adjacent surface of the lower glass wafer), thereby forming a seal that prevents backflow.

Programming jammed Codman Hakim programmable valves: study of an explanted valve and successful programming in a patient.

PubMed

Wong, Sui-To; Wen, Eleanor; Fong, Dawson

2013-08-01

Malfunction of a Codman Hakim programmable valve due to jamming of its programmable component may necessitate shunt revision. The authors report a method for programming jammed Codman Hakim programmable valves by using a Strata II magnet and additional neodymium magnets. The programming method was derived after studying a jammed valve in the laboratory that was explanted from an 10-year-old boy with a history of fourth ventricle ependymoma. Programming the explanted valve with a Codman programmer failed, but rotating a Strata II magnet above the valve resulted in rotation of the spiral cam in the valve. It was found that the Strata II magnet could be used to program the jammed valve by rotating the magnet 90° or multiples of 90° above the valve. The strength of the magnetic field of the Strata II magnet was able to be increased by putting neodymium magnets on it. The programming method was then successfully used in a patient with a jammed Codman Hakim programmable valve. After successful programming using this method, clinical and radiological follow-up of the patient was advised.

Proportional assist ventilation system based on proportional solenoid valve control.

PubMed

Lua, A C; Shi, K C; Chua, L P

2001-07-01

A new proportional assist ventilation (PAV) method using a proportional solenoid valve (PSV) to control air supply to patients suffering from respiratory disabilities, was studied. The outlet flow and pressure from the proportional solenoid valve at various air supply pressures were tested and proven to be suitable for pressure and flow control in a PAV system. In vitro tests using a breathing simulator, which has been proven to possess the general characteristics of human respiratory system in spontaneous breathing tests, were conducted and the results demonstrated the viability of this PAV system in normalizing the breathing patterns of patients with abnormally high resistances and elastances as well as neuromuscular weaknesses. With a back-up safety mechanism incorporated in the control program, pressure "run-away" can be effectively prevented and safe operation of the system can be guaranteed.

Pannus Formation Leads to Valve Malfunction in the Tricuspid Position 19 Years after Triple Valve Replacement.

PubMed

Alskaf, Ebraham; McConkey, Hannah; Laskar, Nabila; Kardos, Attila

2016-06-20

The Medtronic ATS Open Pivot mechanical valve has been successfully used in heart valve surgery for more than two decades. We present the case of a patient who, 19 years following a tricuspid valve replacement with an ATS prosthesis as part of a triple valve operation following infective endocarditis, developed severe tricuspid regurgitation due to pannus formation.

Recurrent pannus formation causing prosthetic aortic valve dysfunction: is excision without valve re-replacement applicable?

PubMed

Darwazah, Ahmad K

2012-06-29

Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function.The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replacement.A recurrent pannus was observed in a female patient who needed repeated surgical intervention to excise a localized pannus without re-replacement of a well functioning prosthetic valve.Management of our case presents several questions, whether recurrence of pannus is caused by sparing the prosthetic valve, is it simply an exaggeration of an inflammatory healing process in certain individuals or is it ideal to re-replace the valve despite a well preserved function.

Analysis of Complex Valve and Feed Systems

NASA Technical Reports Server (NTRS)

Ahuja, Vineet; Hosangadi, Ashvin; Shipman, Jeremy; Cavallo, Peter; Dash, Sanford

2007-01-01

A numerical framework for analysis of complex valve systems supports testing of propulsive systems by simulating key valve and control system components in the test loop. In particular, it is designed to enhance the analysis capability in terms of identifying system transients and quantifying the valve response to these transients. This system has analysis capability for simulating valve motion in complex systems operating in diverse flow regimes ranging from compressible gases to cryogenic liquids. A key feature is the hybrid, unstructured framework with sub-models for grid movement and phase change including cryogenic cavitations. The multi-element unstructured framework offers improved predictions of valve performance characteristics under steady conditions for structurally complex valves such as pressure regulator valve. Unsteady simulations of valve motion using this computational approach have been carried out for various valves in operation at Stennis Space Center such as the split-body valve and the 10-in. (approx.25.4-cm) LOX (liquid oxygen) valve and the 4-in. (approx.10 cm) Y-pattern valve (liquid nitrogen). Such simulations make use of variable grid topologies, thereby permitting solution accuracy and resolving important flow physics in the seat region of the moving valve. An advantage to this software includes possible reduction in testing costs incurred due to disruptions relating to unexpected flow transients or functioning of valve/flow control systems. Prediction of the flow anomalies leading to system vibrations, flow resonance, and valve stall can help in valve scheduling and significantly reduce the need for activation tests. This framework has been evaluated for its ability to predict performance metrics like flow coefficient for cavitating venturis and valve coefficient curves, and could be a valuable tool in predicting and understanding anomalous behavior of system components at rocket propulsion testing and design sites.

High speed exhaust gas recirculation valve

DOEpatents

Fensom, Rod; Kidder, David J.

2005-01-18

In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and it is also desirable to have the EGR valve take up as little space as possible. An exhaust gas recirculation valve is provided that includes an exhaust passage tube, a valve element pivotally mounted within the exhaust passage tube, a linear actuator; and a gear train. The gear train includes a rack gear operatively connected to the linear actuator, and at least one rotatable gear meshing with the rack gear and operatively connected to the valve element to cause rotation of the valve element upon actuation of the linear actuator. The apparatus provides a highly compact package having a high-speed valve actuation capability.

A new one-step procedure for pulmonary valve implantation of the melody valve: Simultaneous prestenting and valve implantation.

PubMed

Boudjemline, Younes

2018-01-01

To describe a new modification, the one-step procedure, that allows interventionists to pre-stent and implant a Melody valve simultaneously. Percutaneous pulmonary valve implantation (PPVI) is the standard of care for managing patients with dysfunctional right ventricular outflow tract, and the approach is standardized. Patients undergoing PPVI using the one-step procedure were identified in our database. Procedural data and radiation exposure were compared to those in a matched group of patients who underwent PPVI using the conventional two-step procedure. Between January 2016 and January 2017, PPVI was performed in 27 patients (median age/range, 19.1/10-55 years) using the one-step procedure involving manual crimping of one to three bare metal stents over the Melody valve. The stent and Melody valve were delivered successfully using the Ensemble delivery system. No complications occurred. All patients had excellent hemodynamic results (median/range post-PPVI right ventricular to pulmonary artery gradient, 9/0-20 mmHg). Valve function was excellent. Median procedural and fluoroscopic times were 56 and 10.2 min, respectively, which significantly differed from those of the two-step procedure group. Similarly, the dose area product (DAP), and radiation time were statistically lower in the one-step group than in the two-step group (P < 0.001 for all variables). After a median follow-up of 8 months (range, 3-14.7), no patient underwent reintervention, and no device dysfunction was observed. The one-step procedure is a safe modification that allows interventionists to prestent and implants the Melody valve simultaneously. It significantly reduces procedural and fluoroscopic times, and radiation exposure. © 2017 Wiley Periodicals, Inc.

Axial computed tomography evaluation of the internal nasal valve correlates with clinical valve narrowing and patient complaint.

PubMed

Moche, Jason A; Cohen, Justin C; Pearlman, Steven J

2013-07-01

The objective of this work was to explore the utility of axial computed tomography (CT) imaging to objectively define a narrow internal nasal valve, and compare those findings with clinical examination and patient complaint. Retrospective review from a single facial plastic surgery center. We reviewed 40 consecutive patients evaluated for either sinusitis or nasal airway obstruction for which a CT scan was obtained at a single radiology institution. Thirty-six complete office records were examined for the presence of clinical internal valve narrowing and complaints of nasal obstruction. In total, 72 internal nasal valves were analyzed using axial plane CT and measurements were compared to clinical findings and presence of airway obstruction. Measured valve areas for clinically normal internal nasal valves averaged 0.47 cm(2) vs 0.28 cm(2) for clinically narrow valves, a decrease of 40.4%. In unobstructed nasal airways the valve area averaged 0.51 cm(2) vs 0.38 cm(2) in obstructed airways, a difference of 25.5%. A radiographically measured valve area of <0.30 cm(2) suggests clinical narrowing with a sensitivity of 71.4%, specificity of 88.9%, positive predictive value of 62.5%, and negative predictive value of 92.3%. Using standard axial CT imaging we describe an objective method of radiographically evaluating the nasal valve, demonstrating strong correlation with physical examination and patient complaint. Additionally, radiographic valve areas can be used to screen for clinically narrow nasal valves with good sensitivity and specificity, providing a novel straightforward method for nasal valve assessment. © 2012 ARS-AAOA, LLC.

Mechanical valve replacement in congenital heart disease.

PubMed

Fiane, A E; Lindberg, H L; Saatvedt, K; Svennevig, J L

1996-05-01

Mechanical valves are the prosthesis of choice in valve replacement in children. However, the problem of somatic growth leading to patient-valve mismatch remains present, and the appropriate anticoagulation regimen remains controversial. We present our experience of valve replacement in a young population over 20 years. Between 1972 and 1992, 48 patients (34 males and 14 females), mean age 11.2 years (range 0.4-27.4 years), underwent mechanical valve replacement at our institution. Aortic valve replacement was performed in 28 patients (58.3%), mitral valve replacement in 13 (27.1%), tricuspid valve replacement in six (12.5%) and pulmonary valve replacement in one patient (2.1%). The prostheses used were: St. Jude Medical (n = 2), Björk-Shiley (n = 14), Medtronic Hall (n = 16), Duromedics (n = 2) and CarboMedics (n = 14). Early mortality was 14.3%, 10.7% for aortic valve replacement and 30.8% for mitral valve replacement. Mean follow up for all patients was 8.3 years (range 0-22 years), with a total of 398 patient-years. Seven patients died during the follow up (17.1%). Survival after 10 years, including operative mortality, was 81% for aortic valve replacement, 33% for mitral valve replacement, 83% for tricuspid valve replacement and 100% for pulmonary valve replacement. All patients were anticoagulated with warfarin. In eight patients (16.7%) an antiplatelet drug (aspirin or dipyridamole) was added. Major events included paravalvular leak in six patients (1.5%/pty), valve thrombosis in five (mitral position in two, tricuspid in three) (1.3%/pty) and endocarditis in one patient (0.3%/pty). Minor thromboembolic events occurred in three patients (0.8%/pty) and minor hemorrhagic events in three (0.8%/pty). No patients developed hemolytic anemia and there was no case of structural failure. In our experience, mechanical prostheses in congenital heart disease were associated with significant morbidity and mortality, however long term survival after aortic valve

Treatment of Symptomatic Severe Aortic Stenosis With a Novel Resheathable Supra-Annular Self-Expanding Transcatheter Aortic Valve System.

PubMed

Manoharan, Ganesh; Walton, Antony S; Brecker, Stephen J; Pasupati, Sanjeevan; Blackman, Daniel J; Qiao, Hongyan; Meredith, Ian T

2015-08-24

The purpose of this study was to prospectively evaluate the safety and clinical performance of the CoreValve Evolut R transcatheter aortic valve replacement (TAVR) system (Medtronic, Inc., Minneapolis, Minnesota) in a single-arm, multicenter pivotal study in high- or extreme-risk patients with symptomatic aortic valve stenosis. Although outcomes following TAVR are improving, challenges still exist. The repositionable 14-F equivalent CoreValve Evolut R TAVR system was developed to mitigate some of these challenges. Suitable patients (n = 60) underwent TAVR with a 26- or 29-mm Evolut R valve. Primary safety endpoints were mortality and stroke at 30 days. Primary clinical performance endpoints were device success per the VARC-2 (Valve Academic Research Consortium-2) and the percent of patients with mild or less aortic regurgitation 24 h to 7 days post-procedure. Patients (66.7% female; mean age 82.8 ± 6.1 years; Society of Thoracic Surgeons Score 7.0 ± 3.7%) underwent TAVR via the transfemoral route in 98.3%, using a 29-mm valve in 68.3% of patients. All attempts at repositioning were successful. No death or stroke was observed up to 30 days. The VARC-2 overall device success rate was 78.6%. Paravalvular regurgitation post TAVR was mild or less in 96.6%, moderate in 3.4%, and severe in 0% at 30 days. Major vascular complications occurred in 8.3%, and permanent pacemaker implantation was required in 11.7% of patients. The repositionable 14-F equivalent Evolut R TAVR system is safe and effective at treating high-risk symptomatic aortic stenosis patients. Repositioning was successful when required in all patients, with low rates of moderate or severe paravalvular aortic regurgitation and low permanent pacemaker implantation. (The Medtronic CoreValve™ Evolut R™ CE Mark Clinical Study; NCT01876420). Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Prosthetic Aortic Valve Fixation Study: 48 Replacement Valves Analyzed Using Digital Pressure Mapping.

PubMed

Lee, Candice Y; Wong, Joshua K; Ross, Ronald E; Liu, David C; Khabbaz, Kamal R; Martellaro, Angelo J; Gorea, Heather R; Sauer, Jude S; Knight, Peter A

Prostheses attachment is critical in aortic valve replacement surgery, yet reliable prosthetic security remains a challenge. Accurate techniques to analyze prosthetic fixation pressures may enable the use of fewer sutures while reducing the risk of paravalvular leaks (PVL). Customized digital thin film pressure transducers were sutured between aortic annulus models and 21-mm bioprosthetic valves with 15 × 4-mm, 12 × 4-mm, or 9 × 6-mm-wide pledgeted mattress sutures. Simulating open and minimally invasive access, 4 surgeons, blinded to data acquisition, each secured 12 valves using manual knot-tying (hand-tied [HT] or knot-pusher [KP]) or automated titanium fasteners (TFs). Real-time pressure measurements and times were recorded. Two-dimensional (2D) and 3D pressure maps were generated for all valves. Pressures less than 80 mm Hg were considered at risk for PVL. Pressures under each knot (intrasuture) fell less than 80 mm Hg for 12 of 144 manual knots (5/144 HT, 7/144 KP) versus 0 of 288 TF (P < 0.001). Pressures outside adjacent sutures (extrasuture) were less than 80 mm Hg in 10 of 60 HT, zero of 60 KP, and zero of 120 TF sites for 15 × 4-mm valves; 17 of 48 HT, 25 of 48 KP, and 12 of 96 TF for 12 × 4-mm valves; and 15 of 36 HT, 17 of 36 KP, and 9 and 72 TF for 9 × 6-mm valves; P < 0.001 all manual versus TF. Annular areas with pressures less than 80 mm Hg ranged from 0% of the sewing-ring area (all open TF) to 31% (12 × 4 mm, KP). The average time per manual knot, 46 seconds (HT, 31 seconds; KP, 61 seconds), was greater than TF, 14 seconds (P < 0.005). Reduced operative times and PVL risk would fortify the advantages of surgical aortic valve replacement. This research encourages continued exploration of technical factors in optimizing prosthetic valve security.

FLUID PRESSURE AND CAM OPERATED VACUUM VALVE

DOEpatents

Batzer, T.H.

1963-11-26

An ultra-high vacuum valve that is bakable, reusable, and capable of being quickly opened and closed is described. A translationally movable valve gate having an annular ridge is adapted to contact an annular soft metal gasket disposed at the valve seat such that the soft metal gasket extends beyond the annular ridge on all sides. The valve gate is closed, by first laterally aligning the valve gate with the valve seat and then bringing the valve gate and valve seat into seating contact by the translational movement of a ramp-like wedging means that engages similar ramp-like stractures at the base of the valve gate to force the valve gate into essentially pressureless contact with the annular soft metal gasket. This gasket is then pressurized from beneath by a fluid thereby effecting a vacuura tight seal between the gasket and the ridge. (AEC)

Flow metering valve

DOEpatents

Blaedel, K.L.

1983-11-03

An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

Flow metering valve

DOEpatents

Blaedel, Kenneth L.

1985-01-01

An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

How Heart Valves Evolve to Adapt to an Extreme-Pressure System: Morphologic and Biomechanical Properties of Giraffe Heart Valves.

PubMed

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 <0.001). No significant difference was found between mitral or pulmonary valves. After normalization for collagen, no significant differences were found in strength between species. The giraffe aortic valve was found to be significantly stiffer than the bovine aortic valve (p <0.001), with no significant difference between mitral and pulmonary valves. On a dry weight basis, the aortic (10.9%), pulmonary (4.3%), and mitral valves (9.6%) of 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

Cavitation guide for control valves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tullis, J.P.

1993-04-01

This guide teaches the basic fundamentals of cavitation to provide the reader with an understanding of what causes cavitation, when it occurs, and the potential problems cavitation can cause to a valve and piping system. The document provides guidelines for understanding how to reduce the cavitation and/or select control valves for a cavitating system. The guide provides a method for predicting the cavitation intensity of control valves, and how the effect of cavitation on a system will vary with valve type, valve function, valve size, operating pressure, duration of operation and details of the piping installation. The guide defines sixmore » cavitation limits identifying cavitation intensities ranging from inception to the maximum intensity possible. The intensity of the cavitation at each limit Is described, including a brief discussion of how each level of cavitation influences the valve and system. Examples are included to demonstrate how to apply the method, including making both size and pressure scale effects corrections. Methods of controlling cavitation are discussed providing information on various techniques which can be used to design a new system or modify an existing one so it can operate at a desired level of cavitation.« less

Recurrent pannus formation causing prosthetic aortic valve dysfunction: Is excision without valve re-replacement applicable?

PubMed Central

2012-01-01

Prosthetic valve dysfunction at aortic position is commonly caused by pannus formation. The exact etiology is not known. It arises from ventricular aspect of the prosthesis encroaching its leaflets causing stenosis or it may remain localized causing left ventricular outflow tract obstruction without affecting valve function. The difference in location entails different approaches in management. Such a pathology requires surgical excision of the pannus with or without valve re-replacement. A recurrent pannus was observed in a female patient who needed repeated surgical intervention to excise a localized pannus without re-replacement of a well functioning prosthetic valve. Management of our case presents several questions, whether recurrence of pannus is caused by sparing the prosthetic valve, is it simply an exaggeration of an inflammatory healing process in certain individuals or is it ideal to re-replace the valve despite a well preserved function. PMID:22747790

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

PubMed

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.

Transcatheter Aortic Valve Implantation for Treatment of Aortic Valve Stenosis: A Health Technology Assessment

PubMed Central

Sehatzadeh, Shayan; Tu, Hong-Anh; Holubowich, Corinne; Higgins, Caroline

2016-01-01

Background Surgical aortic valve replacement (SAVR) is the gold standard for treating aortic valve stenosis. It is a major operation that requires sternotomy and the use of a heart-lung bypass machine, but in appropriately selected patients with symptomatic, severe aortic valve stenosis, the benefits of SAVR usually outweigh the harms. Transcatheter aortic valve implantation (TAVI) is a less invasive procedure that allows an artificial valve to be implanted over the poorly functioning valve. Methods We identified and analyzed randomized controlled trials that evaluated the effectiveness and safety of TAVI compared with SAVR or balloon aortic valvuloplasty and were published before September 2015. The quality of the body of evidence for each outcome was examined according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. The overall quality was determined to be high, moderate, low, or very low using a step-wise, structural methodology. We also developed a Markov decision-analytic model to assess the cost-effectiveness of TAVI compared with SAVR over a 5-year time horizon, and we conducted a 5-year budget impact analysis. Results Rates of cardiovascular and all-cause mortality were similar for the TAVI and SAVR groups in all studies except one, which reported significantly lower all-cause mortality in the TAVI group and a higher rate of stroke in the SAVR group. Trials of high-risk patients who were not suitable candidates for SAVR showed significantly better survival with TAVI than with balloon aortic valvuloplasty. Median survival in the TAVI group was 31 months, compared with 11.7 months in the balloon aortic valvuloplasty group. Compared with SAVR, TAVI was associated with a significantly higher risk of stroke, major vascular complications, paravalvular aortic regurgitation, and the need for a permanent pacemaker. SAVR was associated with a higher risk of bleeding. Transapical TAVI was associated with higher

Quartz ball valve

NASA Technical Reports Server (NTRS)

Goetz, C.; Ingle, W. M. (Inventor)

1980-01-01

A ball valve particularly suited for use in the handling of highly corrosive fluids is described. It is characterized by a valve housing formed of communicating segments of quartz tubing, a pair of communicating sockets disposed in coaxial alignment with selected segments of tubing for establishing a pair of inlet ports communicating with a common outlet port, a ball formed of quartz material supported for displacement between the sockets and configured to be received alternately thereby, and a valve actuator including a rod attached to the ball for selectively displacing the ball relative to each of the sockets for controlling fluid flow through the inlet ports.

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller, unless...

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller, unless...

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller, unless...

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller, unless...

14 CFR 125.137 - Oil valves.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller, unless...

Double-reed exhaust valve engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, Charles L.

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.

Miniature piezo electric vacuum inlet valve

DOEpatents

Keville, Robert F.; Dietrich, Daniel D.

1998-03-24

A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three.

Preoperative planning with three-dimensional reconstruction of patient's anatomy, rapid prototyping and simulation for endoscopic mitral valve repair.

PubMed

Sardari Nia, Peyman; Heuts, Samuel; Daemen, Jean; Luyten, Peter; Vainer, Jindrich; Hoorntje, Jan; Cheriex, Emile; Maessen, Jos

2017-02-01

Mitral valve repair performed by an experienced surgeon is superior to mitral valve replacement for degenerative mitral valve disease; however, many surgeons are still deterred from adapting this procedure because of a steep learning curve. Simulation-based training and planning could improve the surgical performance and reduce the learning curve. The aim of this study was to develop a patient-specific simulation for mitral valve repair and provide a proof of concept of personalized medicine in a patient prospectively planned for mitral valve surgery. A 65-year old male with severe symptomatic mitral valve regurgitation was referred to our mitral valve heart team. On the basis of three-dimensional (3D) transoesophageal echocardiography and computed tomography, 3D reconstructions of the patient's anatomy were constructed. By navigating through these reconstructions, the repair options and surgical access were chosen (minimally invasive repair). Using rapid prototyping and negative mould fabrication, we developed a process to cast a patient-specific mitral valve silicone replica for preoperative repair in a high-fidelity simulator. Mitral valve and negative mould were printed in systole to capture the pathology when the valve closes. A patient-specific mitral valve silicone replica was casted and mounted in the simulator. All repair techniques could be performed in the simulator to choose the best repair strategy. As the valve was printed in systole, no special testing other than adjusting the coaptation area was required. Subsequently, the patient was operated, mitral valve pathology was validated and repair was successfully done as in the simulation. The patient-specific simulation and planning could be applied for surgical training, starting the (minimally invasive) mitral valve repair programme, planning of complex cases and the evaluation of new interventional techniques. The personalized medicine could be a possible pathway towards enhancing reproducibility

Robotic Mitral Valve Repair: The Learning Curve.

PubMed

Goodman, Avi; Koprivanac, Marijan; Kelava, Marta; Mick, Stephanie L; Gillinov, A Marc; Rajeswaran, Jeevanantham; Brzezinski, Anna; Blackstone, Eugene H; Mihaljevic, Tomislav

Adoption of robotic mitral valve surgery has been slow, likely in part because of its perceived technical complexity and a poorly understood learning curve. We sought to correlate changes in technical performance and outcome with surgeon experience in the "learning curve" part of our series. From 2006 to 2011, two surgeons undertook robotically assisted mitral valve repair in 458 patients (intent-to-treat); 404 procedures were completed entirely robotically (as-treated). Learning curves were constructed by modeling surgical sequence number semiparametrically with flexible penalized spline smoothing best-fit curves. Operative efficiency, reflecting technical performance, improved for (1) operating room time for case 1 to cases 200 (early experience) and 400 (later experience), from 414 to 364 to 321 minutes (12% and 22% decrease, respectively), (2) cardiopulmonary bypass time, from 148 to 102 to 91 minutes (31% and 39% decrease), and (3) myocardial ischemic time, from 119 to 75 to 68 minutes (37% and 43% decrease). Composite postoperative complications, reflecting safety, decreased from 17% to 6% to 2% (63% and 85% decrease). Intensive care unit stay decreased from 32 to 28 to 24 hours (13% and 25% decrease). Postoperative stay fell from 5.2 to 4.5 to 3.8 days (13% and 27% decrease). There were no in-hospital deaths. Predischarge mitral regurgitation of less than 2+, reflecting effectiveness, was achieved in 395 (97.8%), without correlation to experience; return-to-work times did not change substantially with experience. Technical efficiency of robotic mitral valve repair improves with experience and permits its safe and effective conduct.

Noninvasive valve monitor using alternating electromagnetic field

DOEpatents

Eissenberg, David M.; Haynes, Howard D.; Casada, Donald A.

1993-01-01

One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

Noninvasive valve monitor using alternating electromagnetic field

DOEpatents

Eissenberg, D.M.; Haynes, H.D.; Casada, D.A.

1993-03-16

One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

Triple valve surgery: a 25-year experience.

PubMed

Yilmaz, Mustafa; Ozkan, Murat; Böke, Erkmen

2004-09-01

Surgical treatment of rheumatic valvular disease still constitutes a significant number of cardiac operations in developing countries. Despite improvements in myocardial protection and cardiopulmonary bypass techniques, triple valve operations (aortic, mitral and tricuspid valves) are still challenging because of longer duration of cardiopulmonary bypass and higher degree of myocardial decompensation. This study was instituted in order to assess results of triple valve surgery. Between 1977 and 2002, 34 patients underwent triple valve surgery in our clinic by the same surgeon (EB). Eleven patients underwent triple valve replacement (32.4%) and 23 underwent tricuspid valve annuloplasty with aortic and mitral valve replacements (67.6%). There was no significant difference between the two groups of patients who underwent triple valve replacement and aortic and mitral valve replacement with tricuspid valve annuloplasty. There were 4 hospital deaths (11.8%) occurring within 30 days. The duration of follow-up for 30 survivors ranged from 6 to 202 months (mean 97 months). The actuarial survival rates were 85%, 72%, and 48% at 5, 10, and 15 years respectively. Actuarial freedom from reoperation rates at 5, 10, and 15 years was 86.3%, 71.9%, and 51.2%, respectively. Freedom from cerebral thromboembolism and anticoagulation-related hemorrhage rates, expressed in actuarial terms was 75.9% and 62.9% at 5 and 10 years. Major cerebral complications occurred in 10 of the 30 patients. We prefer replacing, if repairing is not possible, the tricuspid valve, with a bileaflet mechanical prosthesis in a patient with valve replacement of the left heart who will be anticoagulated in order to avoid unfavorable properties of bioprosthesis like degeneration and of old generation mechanical prosthesis like thrombosis and poor hemodynamic function. In recent years, results of triple valve surgery either with tricuspid valve conservation or valve replacement in suitable cases have become

Tricuspid regurgitation and right ventricular function after mitral valve surgery with or without concomitant tricuspid valve procedure

PubMed Central

Desai, Ravi R.; Vargas Abello, Lina Maria; Klein, Allan L.; Marwick, Thomas H.; Krasuski, Richard A.; Ye, Ying; Nowicki, Edward R.; Rajeswaran, Jeevanantham; Blackstone, Eugene H.; Pettersson, Gösta B.

2014-01-01

Objectives To study the effect of mitral valve repair with or without concomitant tricuspid valve repair on functional tricuspid regurgitation and right ventricular function. Methods From 2001 to 2007, 1833 patients with degenerative mitral valve disease, a structurally normal tricuspid valve, and no coronary artery disease underwent mitral valve repair, and 67 underwent concomitant tricuspid valve repair. Right ventricular function (myocardial performance index and tricuspid annular plane systolic excursion) was measured before and after surgery using transthoracic echocardiography for randomly selected patients with tricuspid regurgitation grade 0, 1+, and 2+(100 patients for each grade) and 93 with grade 3+/4+, 393 patients in total. Results In patients with mild (<3+) preoperative tricuspid regurgitation, mitral valve repair alone was associated with reduced tricuspid regurgitation and mild worsening of right ventricular function. Tricuspid regurgitation of 2+or greater developed in fewer than 20%, and right ventricular function had improved, but not to preoperative levels, at 3 years. In patients with severe (3+/4+) preoperative tricuspid regurgitation, mitral valve repair alone reduced tricuspid regurgitation and improved right ventricular function; however, tricuspid regurgitation of 2+ or greater returned and right ventricular function worsened toward preoperative levels within 3 years. Concomitant tricuspid valve repair effectively eliminated severe tricuspid regurgitation and improved right ventricular function. Also, over time, tricuspid regurgitation did not return and right ventricular function continued to improve to levels comparable to that of patients with lower grades of preoperative tricuspid regurgitation. Conclusions In patients with mitral valve disease and severe tricuspid regurgitation, mitral valve repair alone was associated with improved tricuspid regurgitation and right ventricular function. However, the improvements were incomplete and

[Transcatheter aortic valve replacement].

PubMed

Sawa, Yoshiki

2014-07-01

While transcatheter aortic valve replacement( TAVR) has spread rapidly all over the world for highrisk patients with severe aortic stenosis (AS), SAPIEN XT was approved in Japan in October 2013. Since that, approximately 400 TAVR cases were performed in Japan. In our institute, we have performed 164 cases since first case in Japan in 2009 and have achieved satisfactory early results(30-day mortality:1.2%). At the same time, however, simultaneously various TAVR-related complications including a paravalvular leak, stroke, vascular complications, and coronary obstruction were observed. A reduction in the incidence and severity of these complications had led technical improvements in various new devices(2nd generation TAVR device such as the SAPIEN 3, ACURATE, and JenaValve) and in implantation techniques including repositioning/recapturing features, paravalvular sealing technologies, and prevention of coronary obstruction. Furthermore, there is also increasing experience with special indications for TAVR such as pure aortic valve insufficiency or valve-in-valve techniques. Currently, an increasing number of publications of midterm results demonstrate good prosthetic valve function and durability, with good quality of life and low morbidity after TAVR. There are also some randomized trials such as PARTNER 2 or SURTAVI to investigate potential benefits of TAVR for intermediate-risk patients. These improvements in the TAVR devices promises the expansion of TAVR towards the treatment of lower-risk patients in the near future.

Improved solenoid valve design

NASA Technical Reports Server (NTRS)

Evans, J.

1969-01-01

Modified solenoid valve reduces valve seat loading by eliminating off-center operation of the armature, reducing the poppet size and spring-cushioning its impact, and reducing armature impact with a poppet guide stop.

Miniature piezo electric vacuum inlet valve

DOEpatents

Keville, R.F.; Dietrich, D.D.

1998-03-24

A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability is disclosed. The low power (<1.6 watts), high pulse rate (<2 milliseconds), variable flow inlet valve is utilized for mass spectroscopic applications or other applications where pulsed or continuous flow conditions are needed. The inlet valve also has a very minimal dead volume of less than 0.01 std/cc. The valve can utilize, for example, a 12 Vdc input/750 Vdc, 3 mA output power supply compared to conventional piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three. 6 figs.

Latching Solenoid-Operated Ball Valve

NASA Technical Reports Server (NTRS)

Brudnicki, Myron

1994-01-01

Proposed solenoid-operated ball valve latches in open or closed position until energized to change position. Electrical energy consumed only during opening or closing motion. Valve ball contains central channel through which fluid could flow. Made of highly magnetically permeable steel. When appropriate coil(s) energized by brief pulse (or pulses) of electrical current at appropriate polarity, ball rotates clockwise until permanent magnets come to rest against hard stops in housing, and inlet and outlet ports aligned with central channel so fluid flows through valve. Magnets adhere to stops by magnetic attraction, latching valve in open position. To close valve, appropriate coil(s) energized by pulse (or pulses) of appropriate polarity to generate magnetic forces rotating ball counterclockwise until magnets make contact with hard stops, and inlet and outlet ports sealed.

A Parylene MEMS Electrothermal Valve

PubMed Central

Li, Po-Ying; Givrad, Tina K.; Holschneider, Daniel P.; Maarek, Jean-Michel I.; Meng, Ellis

2011-01-01

The first microelectromechanical-system normally closed electrothermal valve constructed using Parylene C is described, which enables both low power (in milliwatts) and rapid operation (in milliseconds). This low-power valve is well suited for applications in wirelessly controlled implantable drug-delivery systems. The simple design was analyzed using both theory and modeling and then characterized in benchtop experiments. Operation in air (constant current) and water (current ramping) was demonstrated. Valve-opening powers of 22 mW in air and 33 mW in water were obtained. Following integration of the valve with catheters, our valve was applied in a wirelessly operated microbolus infusion pump, and the in vivo functionality for the appropriateness of use of this pump for future brain mapping applications in small animals was demonstrated. PMID:21350679

Effectiveness of rivaroxaban for thromboprophylaxis of prosthetic heart valves in a porcine heterotopic valve model.

PubMed

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

Heart Valve Biomechanics and Underlying Mechanobiology

PubMed Central

Ayoub, Salma; Ferrari, Giovanni; Gorman, Robert C.; Gorman, Joseph H.; Schoen, Frederick J.; Sacks, Michael S.

2017-01-01

Heart valves control unidirectional blood flow within the heart during the cardiac cycle. They have a remarkable ability to withstand the demanding mechanical environment of the heart, achieving lifetime durability by processes involving the ongoing remodeling of the extracellular matrix. The focus of this review is on heart valve functional physiology, with insights into the link between disease-induced alterations in valve geometry, tissue stress, and the subsequent cell mechanobiological responses and tissue remodeling. We begin with an overview of the fundamentals of heart valve physiology and the characteristics and functions of valve interstitial cells (VICs). We then provide an overview of current experimental and computational approaches that connect VIC mechanobiological response to organ- and tissue-level deformations and improve our understanding of the underlying functional physiology of heart valves. We conclude with a summary of future trends and offer an outlook for the future of heart valve mechanobiology, specifically, multiscale modeling approaches, and the potential directions and possible challenges of research development. PMID:27783858

TUBE SHEARING VALVE

DOEpatents

Wilner, L.B.

1960-05-24

Explosive operated valves can be used to join two or more containers in fluid flow relationship, one such container being a sealed reservoir. The valve is most simply disposed by mounting it on the reservoir so thst a tube extends from the interior of the reservoir through the valve body, terminating at the bottom of the bore in a closed end; other containers may be similarly connected or may be open connected, as desired. The piston of the valve has a cutting edge at its lower end which shears off the closed tube ends and a recess above the cutting edge to provide a flow channel. Intermixing of the fluid being transferred with the explosion gases is prevented by a copper ring at the top of the piston which is force fitted into the bore at the beginning of the stroke. Although designed to avoid backing up of the piston at pressures up to 10,000 psi in the transferred fluid, proper operation is independent of piston position, once the tube ends were sheared.

Problem: Heart Valve Regurgitation

MedlinePlus

... should be completely closed For example: Watch an animation of mitral valve regurgitation A leaking mitral valve ... Not Alone Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Problem: Mitral Valve Regurgitation

MedlinePlus

... each time the left ventricle contracts. Watch an animation of mitral valve regurgitation A leaking mitral valve ... Not Alone Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Heart Attack Symptoms ...

Mitral valve surgery - open

MedlinePlus

... place. There are two types of mitral valves: Mechanical, made of man-made (synthetic) materials, such as ... Mechanical heart valves last a lifetime. However, blood clots may develop on them. This can cause them ...

Are anticoagulant independent mechanical valves within reach-fast prototype fabrication and in vitro testing of innovative bi-leaflet valve models.

PubMed

Scotten, Lawrence N; Siegel, Rolland

2015-08-01

Exploration for causes of prosthetic valve thrombogenicity has frequently focused on forward or post-closure flow detail. In prior laboratory studies, we uncovered high amplitude flow velocities of short duration close to valve closure implying potential for substantial shear stress with subsequent initiation of blood coagulation pathways. This may be relevant to widely accepted clinical disparity between mechanical and tissue valves vis-à-vis thrombogenicity. With a series of prototype bi-leaflet mechanical valves, we attempt reduction of closure related velocities with the objective of identifying a prototype valve with thrombogenic potential similar to our tissue valve control. This iterative design approach may find application in preclinical assessment of valves for anticoagulation independence. Tested valves included: prototype mechanical bi-leaflet BVs (n=56), controls (n=2) and patented early prototype mechanicals (n=2) from other investigators. Pulsatile and quasi-steady flow systems were used for testing. Projected dynamic valve area (PDVA) was measured using previously described novel technology. Flow velocity over the open and closing periods was determined by volumetric flow rate/PDVA. For the closed valve interval, use was made of data obtained from quasi-steady back pressure/flow tests. Performance was ranked by a proposed thrombogenicity potential index (TPI) relative to tissue and mechanical control valves. Optimization of the prototype valve designs lead to a 3-D printed model (BV3D). For the mitral/aortic site, BV3D has lower TPI (1.10/1.47) relative to the control mechanical valve (3.44/3.93) and similar to the control tissue valve (ideal TPI ≤1.0). Using unique technology, rapid prototyping and thrombogenicity ranking, optimization of experimental valves for reduced thrombogenic potential was expedited and simplified. Innovative mechanical valve configurations were identified that merit consideration for further development which may bring

Are anticoagulant independent mechanical valves within reach—fast prototype fabrication and in vitro testing of innovative bi-leaflet valve models

PubMed Central

Siegel, Rolland

2015-01-01

Background Exploration for causes of prosthetic valve thrombogenicity has frequently focused on forward or post-closure flow detail. In prior laboratory studies, we uncovered high amplitude flow velocities of short duration close to valve closure implying potential for substantial shear stress with subsequent initiation of blood coagulation pathways. This may be relevant to widely accepted clinical disparity between mechanical and tissue valves vis-à-vis thrombogenicity. With a series of prototype bi-leaflet mechanical valves, we attempt reduction of closure related velocities with the objective of identifying a prototype valve with thrombogenic potential similar to our tissue valve control. This iterative design approach may find application in preclinical assessment of valves for anticoagulation independence. Methods Tested valves included: prototype mechanical bi-leaflet BVs (n=56), controls (n=2) and patented early prototype mechanicals (n=2) from other investigators. Pulsatile and quasi-steady flow systems were used for testing. Projected dynamic valve area (PDVA) was measured using previously described novel technology. Flow velocity over the open and closing periods was determined by volumetric flow rate/PDVA. For the closed valve interval, use was made of data obtained from quasi-steady back pressure/flow tests. Performance was ranked by a proposed thrombogenicity potential index (TPI) relative to tissue and mechanical control valves. Results Optimization of the prototype valve designs lead to a 3-D printed model (BV3D). For the mitral/aortic site, BV3D has lower TPI (1.10/1.47) relative to the control mechanical valve (3.44/3.93) and similar to the control tissue valve (ideal TPI ≤1.0). Conclusions Using unique technology, rapid prototyping and thrombogenicity ranking, optimization of experimental valves for reduced thrombogenic potential was expedited and simplified. Innovative mechanical valve configurations were identified that merit consideration

Torque-actuated valves for microfluidics.

PubMed

Weibel, Douglas B; Kruithof, Maarten; Potenta, Scott; Sia, Samuel K; Lee, Andrew; Whitesides, George M

2005-08-01

This paper describes torque-actuated valves for controlling the flow of fluids in microfluidic channels. The valves consist of small machine screws (> or =500 microm) embedded in a layer of polyurethane cast above microfluidic channels fabricated in poly(dimethylsiloxane) (PDMS). The polyurethane is cured photochemically with the screws in place; on curing, it bonds to the surrounding layer of PDMS and forms a stiff layer that retains an impression of the threads of the screws. The valves were separated from the ceiling of microfluidic channels by a layer of PDMS and were integrated into channels using a simple procedure compatible with soft lithography and rapid prototyping. Turning the screws actuated the valves by collapsing the PDMS layer between the valve and channel, controlling the flow of fluids in the underlying channels. These valves have the useful characteristic that they do not require power to retain their setting (on/off). They also allow settings between "on" and "off" and can be integrated into portable, disposable microfluidic devices for carrying out sandwich immunoassays.

Proof-of-Concept Evaluation of the SailValve Self-Expanding Deep Venous Valve System in a Porcine Model.

PubMed

Boersma, Doeke; Vink, Aryan; Moll, Frans L; de Borst, Gert J

2017-06-01

To evaluate the SailValve, a new self-expanding deep venous valve concept based on a single polytetrafluoroethylene cusp floating up and down in the bloodstream like a sail, acting as a flow regulator and allowing minimal reflux to reduce thrombogenicity. Both iliac veins of 5 pigs were implanted with SailValve devices; the first animal was an acute pilot experiment to show the feasibility of accurately positioning the SailValve via a femoral access. The other 4 animals were followed for 2 weeks (n=2) or 4 weeks (n=2) under a chronic implantation protocol. Patency and valve function were evaluated directly in all animals using ascending and descending phlebography after device placement and at termination in the chronic implant animals. For reasons of clinical relevance, a regimen of clopidogrel and calcium carbasalate was administered. Histological analysis was performed according to a predefined protocol by an independent pathologist. Deployment was technically feasible in all 10 iliac veins, and all were patent directly after placement. No perioperative or postoperative complications occurred. Ascending phlebograms in the follow-up animals confirmed the patency of all valves after 2 or 4 weeks. Descending phlebograms showed full function in 5 of 8 valves. Limited reflux was seen in 1 valve (4-week group), and the function in the remaining 2 valves (2-week group) was insufficient because of malpositioning. No macroscopic thrombosis was noted on histology. Histology in the follow-up groups revealed a progressive inflammatory reaction to the valves. This animal study shows the potential of the SailValve concept with sufficient valve function after adequate positioning and no (thrombogenic) occlusions after short-term follow-up. Future research is essential to optimize valve material and long-term patency.

Valve-spring Surge

NASA Technical Reports Server (NTRS)

Marti, Willy

1937-01-01

Test equipment is described that includes a system of three quartz indicators whereby three different pressures could be synchronized and simultaneously recorded on a single oscillogram. This equipment was used to test the reliction of waves at ends of valve spring, the dynamical stress of the valve spring for a single lift of the valve, and measurement of the curve of the cam tested. Other tests included simultaneous recording of the stress at both ends of the spring, spring oscillation during a single lift as a function of speed, computation of amplitude of oscillation for a single lift by harmonic analysis, effect of cam profile, the setting up of resonance, and forced spring oscillation with damping.

Mitral valve disease—morphology and mechanisms

PubMed Central

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

2016-01-01

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

THERMALLY OPERATED VAPOR VALVE

DOEpatents