Follow-up of the original cohort with the Ahmed glaucoma valve implant.

PubMed

Topouzis, F; Coleman, A L; Choplin, N; Bethlem, M M; Hill, R; Yu, F; Panek, W C; Wilson, M R

1999-08-01

To study the long-term results of the Ahmed glaucoma valve implant in patients with complicated glaucoma in whom short-term results have been reported. In this multicenter study, we analyzed the long-term outcome of a cohort of 60 eyes from 60 patients in whom the Ahmed glaucoma valve was implanted. Failure was characterized by at least one of the following: intraocular pressure greater than 21 mm Hg at both of the last two visits less than 6 mm Hg at both of the last two visits, loss of light perception, additional glaucoma surgery, devastating complications, and removal or replacement of the Ahmed glaucoma valve implant. Devastating complications included chronic hypotony, retinal detachment, malignant glaucoma, endophthalmitis, and phthisis bulbi; we also report results that add corneal complications (corneal decompensation or edema, corneal graft failure) as defining a devastating complication. The mean follow-up time for the 60 eyes was 30.5 months (range, 2.1 to 63.5). When corneal complications were included in the definition of failure, 26 eyes (43%) were considered failures. Cumulative probabilities of success at 1, 2, 3, and 4 years were 76%, 68%, 54%, and 45%, respectively. When corneal complications were excluded from the definition of failure, 13 eyes (21.5%) were considered failures. Cumulative probabilities of success at 1, 2, 3, and 4 years were 87%, 82%, 76%, and 76%, respectively. Most of the failures after 12 months of postoperative follow-up were because of corneal complications. The long-term performance of the Ahmed glaucoma valve implant is comparable to other drainage devices. More than 12 months after the implantation of the Ahmed glaucoma valve implant, the most frequent adverse outcome was corneal decompensation or corneal graft failure. These corneal problems may be secondary to the type of eyes that have drainage devices or to the drainage device itself. Further investigation is needed to identify the reasons that corneal problems

Pirfenidone inhibits fibrosis in foreign body reaction after glaucoma drainage device implantation

PubMed Central

Jung, Kyoung In; Park, Chan Kee

2016-01-01

Background The aim of this study was to investigate the antiscarring effects of pirfenidone on foreign body reaction in a rabbit model of glaucoma drainage implant surgery. Methods Adult New Zealand White rabbits had glaucoma drainage device implantation using Model FP8 Ahmed glaucoma valves. One eye was randomly assigned to receive postoperative intrableb injection of pirfenidone followed by topical treatment. The other eye underwent the same procedure but without the addition of pirfenidone. Histochemical staining and immunohistochemistry for blebs were performed. Results The degree of cellularity was smaller in the pirfenidone group than in the control group at 2 weeks post operation (P=0.005). A few foreign body giant cells were detected in the inner border of the capsule, and their numbers were similar in the control and pirfenidone groups (P>0.05). Using Masson’s trichrome stain, the inner collagen-rich layer was found to be thinner in the pirfenidone group than the control group at 4 weeks (P=0.031) and 8 weeks (P=0.022) post operation. The percentage of proliferating cell nuclear antigen-positive cells was lower in the pirfenidone group than in the control group at 2 weeks post operation (total bleb, P=0.022; inner bleb, P=0.036). Pirfenidone treatment decreased the immunoreactivity of connective tissue growth factor at 2 weeks post operation (total bleb, P=0.029; inner bleb, P=0.018). The height and area of α-smooth muscle actin expression were lower in the pirfenidone group than the control group at 2 weeks, 4 weeks, and 8 weeks post operation (all P<0.05). Conclusion Postoperative intrableb injection of pirfenidone followed by topical administration reduced fibrosis following glaucoma drainage device implantation. These findings suggest that pirfenidone may function as an antiscarring treatment in foreign body reaction after tube-shunt surgery. PMID:27143855

Pirfenidone inhibits fibrosis in foreign body reaction after glaucoma drainage device implantation.

PubMed

Jung, Kyoung In; Park, Chan Kee

2016-01-01

The aim of this study was to investigate the antiscarring effects of pirfenidone on foreign body reaction in a rabbit model of glaucoma drainage implant surgery. Adult New Zealand White rabbits had glaucoma drainage device implantation using Model FP8 Ahmed glaucoma valves. One eye was randomly assigned to receive postoperative intrableb injection of pirfenidone followed by topical treatment. The other eye underwent the same procedure but without the addition of pirfenidone. Histochemical staining and immunohistochemistry for blebs were performed. The degree of cellularity was smaller in the pirfenidone group than in the control group at 2 weeks post operation (P=0.005). A few foreign body giant cells were detected in the inner border of the capsule, and their numbers were similar in the control and pirfenidone groups (P>0.05). Using Masson's trichrome stain, the inner collagen-rich layer was found to be thinner in the pirfenidone group than the control group at 4 weeks (P=0.031) and 8 weeks (P=0.022) post operation. The percentage of proliferating cell nuclear antigen-positive cells was lower in the pirfenidone group than in the control group at 2 weeks post operation (total bleb, P=0.022; inner bleb, P=0.036). Pirfenidone treatment decreased the immunoreactivity of connective tissue growth factor at 2 weeks post operation (total bleb, P=0.029; inner bleb, P=0.018). The height and area of α-smooth muscle actin expression were lower in the pirfenidone group than the control group at 2 weeks, 4 weeks, and 8 weeks post operation (all P<0.05). Postoperative intrableb injection of pirfenidone followed by topical administration reduced fibrosis following glaucoma drainage device implantation. These findings suggest that pirfenidone may function as an antiscarring treatment in foreign body reaction after tube-shunt surgery.

[Postoperative Follow-Up of Glaucoma Drainage Devices].

PubMed

Dietlein, T S; Neugebauer, A; Fricke, J; Lappas, A; Rosentreter, A

2016-05-01

There is an increasing trend towards using glaucoma drainage implants. The postoperative management of such devices depends on their technical characteristics and specific complications. The Baerveldt glaucoma implant with its larger surface area has been shown to lower mean intraocular pressure more effectively than the Ahmed-FP7 implant. As a non-valve implant, however, it has been associated with a higher rate of severe complications, particularly ocular hypotension. Moreover, glaucoma implants may induce diplopia if they interfere with extraocular muscles. Topical treatment with antibiotics and steroids is necessary in cases of intraocular inflammation. In refractory cases, the tube may even have to be removed. Surgical reposition of the tube may be indicated when it is severely dislocated. Increased intraocular pressure is primarily treated by pressure-lowering medications during postoperative follow-up. If topical glaucoma medication is insufficient to control increases in intraocular pressure due to encapsulation, a second implant may be considered or the capsule surrounding the implant may be excised to reduce outflow resistance or additional cyclodestructive procedures can be performed. Chronic hypotension may be treated with tube ligation or occlusion. Severe corneal oedema may require lamellar keratoplasty. Conjunctival erosions with tube exposure or tube retractions also require surgical correction. Georg Thieme Verlag KG Stuttgart · New York.

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...

Combined Scleral Flap with Donor Scleral Patch Graft for Anterior Tube Placement in Glaucoma Drainage Device Surgery.

PubMed

Yu, Jea H; Nguyen, Chuck; Gallemore, Esmeralda; Gallemore, Ron P

2016-01-01

Purpose . To report a new technique for anterior placement of tubes for glaucoma drainage devices to reduce the risk of tube erosions. Methods . Retrospective review of select cases of Ahmed Valve surgery combined with the novel method of a limbal-based scleral flap covered by a scleral patch graft to cover the tube at the entrance through the limbus. Intraoperative and postoperative illustrations are shown to highlight the method of tube placement. Results . In this retrospective case series, 3 patients are presented illustrating the technique. Two had neovascular glaucoma and one had primary open-angle glaucoma (POAG). On average, intraocular pressure was reduced from 39 ± 14 mmHg to 15 ± 2 mmHg and the number of glaucoma medications was reduced from 4 ± 1 to 0. Preoperative and most recent visual acuities were hand-motion (HM) and HM, 20/60 and 20/50, and 20/70 and 20/30, respectively. Conclusion . The combination of a limbal-based scleral flap with scleral patch graft to cover the tube with glaucoma drainage devices may be an effective means to reduce erosion and protect against endophthalmitis.

Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices.

PubMed

Hulme, S Elizabeth; Shevkoplyas, Sergey S; Whitesides, George M

2009-01-07

This paper describes a method for prefabricating screw, pneumatic, and solenoid valves and embedding them in microfluidic devices. This method of prefabrication and embedding is simple, requires no advanced fabrication, and is compatible with soft lithography. Because prefabrication allows many identical valves to be made at one time, the performance across different valves made in the same manner is reproducible. In addition, the performance of a single valve is reproducible over many cycles of opening and closing: an embedded solenoid valve opened and closed a microfluidic channel more than 100,000 times with no apparent deterioration in its function. It was possible to combine all three types of prefabricated valves in a single microfluidic device to control chemical gradients in a microfluidic channel temporally and spatially.

New-generation devices for transcatheter aortic valve implantation.

PubMed

Gatto, Laura; Biondi-Zoccai, Giuseppe; Romagnoli, Enrico; Frati, Giacomo; Prati, Francesco; Giordano, Arturo

2018-04-20

Transcatheter aortic valve implantation (TAVI) has overcome the pioneering phase and thanks to accrued clinical evidence has become a mainstay alternative to surgical aortic valve replacement (SAVR) in patients at high risk for post-operative complications. Despite these successes, TAVI remains a junior technology facing momentous developments in techniques and devices. Indeed, several new-generation devices for TAVI have become available in the last few years, including Acurate, Allegra, Evolut, Lotus, JenaValve, Portico, and SAPIEN3. Despite the inevitable setbacks, such as the one represented by DirectFlow, these new devices appear associated with comparative benefits, especially for minimal invasiveness, rates of permanent pacemaker implantation, and risk of residual aortic regurgitation. Indeed, no single device appears clearly better than the others, and a tailored and individualized approach should be sought in using these prostheses, taking into account operator and institutional expertise, on top of patient features. Few comparative effectiveness studies are available to date to guide decision making, and thus careful scrutiny is needed even in everyday clinical practice, especially if seeking to expand the current indications of TAVI. Further guidance will however come from long-term follow-up of completed studies and from results of ongoing trials.

Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices

PubMed Central

Hulme, S. Elizabeth; Shevkoplyas, Sergey S.

2011-01-01

This paper describes a method for prefabricating screw, pneumatic, and solenoid valves and embedding them in microfluidic devices. This method of prefabrication and embedding is simple, requires no advanced fabrication, and is compatible with soft lithography. Because prefabrication allows many identical valves to be made at one time, the performance across different valves made in the same manner is reproducible. In addition, the performance of a single valve is reproducible over many cycles of opening and closing: an embedded solenoid valve opened and closed a microfluidic channel more than 100,000 times with no apparent deterioration in its function. It was possible to combine all three types of prefabricated valves in a single microfluidic device to control chemical gradients in a microfluidic channel temporally and spatially. PMID:19209338

Propionibacterium acnes endophthalmitis in Ahmed glaucoma valve.

PubMed

Gutiérrez-Díaz, E; Montero-Rodríguez, M; Mencía-Gutiérrez, E; Fernández-González, M C; Pérez-Blázquez, E

2001-01-01

To report a case of Propionibacterium acnes endophthalmitis in a patient with an Ahmed glaucoma valve. A nine-year-old boy with bilateral congenital glaucoma, with an Ahmed glaucoma valve implanted in the left eye, had recurrent conjunctival dehiscence and endophthalmitis. Vitreous cultures demonstrated the presence of Propionibacterium acnes. This is the first reported case of Propionibacterium acnes endophthalmitis in an Ahmed glaucoma valve and the second one in a glaucoma drainage device. We strongly recommend using a patch graft to prevent and treat tube exposure. Conjunctival grafts may be useful to close the conjunctiva when there is marked scarring to prevent patch exposure and melting or extrusion.

Rankine cycle condenser pressure control using an energy conversion device bypass valve

DOEpatents

Ernst, Timothy C; Nelson, Christopher R; Zigan, James A

2014-04-01

The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

Concomitant transcatheter aortic valve and left ventricular assist device implantation.

PubMed

Baum, Christina; Seiffert, Moritz; Treede, Hendrik; Reichenspurner, Hermann; Deuse, Tobias

2013-01-01

Relevant aortic regurgitation (AR) requires surgical repair at the time of left ventricular assist device (LVAD) implantation to reduce recirculation and ensure adequate forward flow. We report here on a patient with moderate AR in a noncalcified aortic valve and extensive calcification of the ascending aorta. The latter precluded aortic-crossclamping and, thus, surgical intervention on the aortic valve. Although there were no valvular or annular calcifications, a JenaValve transcatheter heart valve was successfully placed transapically with subsequent LVAD implantation in one operation. We believe concomitant transcatheter aortic valve implantation (TAVI) and LVAD implantation is a promising hybrid procedure, even in patients with pure AR.

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...

The importance of valve alignment in determining the pressure/flow characteristics of differential pressure shunt valves with anti-gravity devices.

PubMed

Francel, P C; Stevens, F A; Tompkins, P; Pollay, M

2001-02-01

The proper functioning of shunt valves in vivo is dependent on many factors, including the valve itself, the anti-siphon device or ASD (if included), patency of inlet and outlet tubing, and location of the valve. One important, but sometimes overlooked, consideration in valve function is the valve location relative to the tip of the ventricular inlet catheter. As with any pressure measurement, the zero or reference position is an important concept. In the case of shunt valves, the position of the proximal inlet catheter tip is fixed and therefore serves as the reference point for all pressure measurements. This study was conducted to document the importance of this relationship for the pressure/flow characteristics of the shunt valve. We bench-tested differential pressure valves (with integral anti-gravity devices; AGDs) from three manufacturers. Valves were connected to an "infinite" reservoir, and the starting head pressure for each was determined from product inserts. The inlet catheter tip was fixed at this position, and the valve body was moved in relation to the inlet catheter tip. Outflow rates were determined gravimetrically for positions varying between 4 cm above and 8 cm below the inlet catheter tip. All differential pressure valves utilized in this study that contained AGDs showed significant increases in outflow rate as the valve body was moved incrementally below the level of the inlet catheter tip. To allow functioning as a zero-hydrostatic pressure differential pressure valve, the AGD and the inlet catheter tip should be aligned at the same horizontal level.

Durability of central aortic valve closure in patients with continuous flow left ventricular assist devices.

PubMed

McKellar, Stephen H; Deo, Salil; Daly, Richard C; Durham, Lucian A; Joyce, Lyle D; Stulak, John M; Park, Soon J

2014-01-01

A competent aortic valve is essential to providing effective left ventricular assist device support. We have adopted a practice of central aortic valve closure by placing a simple coaptation stitch at left ventricular assist device implantation in patients with significant aortic insufficiency. We conducted a follow-up study to evaluate the efficacy and durability of this procedure. The study included patients who had undergone continuous flow left ventricular assist device implantation. The patients were divided into 2 groups, those who did not require any aortic procedure because the valve was competent and those who underwent central aortic valve closure for mild or greater aortic regurgitation. The clinical endpoints were mortality, progression or recurrence of aortic insufficiency, and reoperation for aortic valve pathologic features. Aortic insufficiency was measured qualitatively from mild to severe on a scale of 0 to 5. A total of 123 patients received continuous flow left ventricular assist devices from February 2007 to August 2011. Of those, 18 (15%) underwent central aortic valve closure at left ventricular assist device implantation because of significant aortic insufficiency (1.8 ± 1.4) and 105 who did not (competent aortic valve, 0.15 ± 0.43; P < .01). At follow-up (median, 312 days; range, 0-1429 days), the mean aortic insufficiency score remained low for the patients with central aortic valve closure (0.27 ± 0.46) in contrast to those without central aortic valve closure who experienced aortic insufficiency progression (0.78 ± 0.89; P = .02). In addition, the proportion of patients with more than mild aortic insufficiency was significantly less in the central aortic valve closure group (0% vs 18%; P = .05). The patients in the central aortic valve closure group were significantly older and had a greater incidence of renal failure at baseline. The 30-day mortality was greater in the central aortic valve closure group, but the late survival

The predictive value of external continuous lumbar drainage, with cerebrospinal fluid outflow controlled by medium pressure valve, in normal pressure hydrocephalus.

PubMed

Panagiotopoulos, V; Konstantinou, D; Kalogeropoulos, A; Maraziotis, T

2005-09-01

Although sporadic studies have described temporary external cerebrospinal fluid (CSF) lumbar drainage as a highly accurate test for predicting the outcome after ventricular shunting in normal pressure hydrocephalus (NPH) patients, a more recent study reports that the positive predictive value of external lumbar drainage (ELD) is high but the negative predictive value is deceptively low. Therefore, we conducted a prospective study in order to evaluate the predictive value of a continuous ELD, with CSF outflow controlled by medium pressure valve, in NPH patients. Twenty-seven patients with presumed NPH were admitted to our department and CSF drainage was carried out by a temporary (ELD) with CSF outflow controlled by a medium pressure valve for five days. All patients received a ventriculoperitoneal shunt using a medium pressure valve based upon preoperative clinical and radiographic criteria of NPH, regardless of ELD outcome. Clinical evaluation of gait disturbances, urinary incontinence and mental status, and radiological evaluation with brain CT was performed prior to and after ELD test, as well as three months after shunting. Twenty-two patients were finally shunted and included in this study. In a three-month follow-up, using a previously validated score system, overall improvement after permanent shunting correlated well to improvement after ELD test (Spearman's rho = 0.462, p = 0.03). When considering any degree of improvement as a positive response, ELD test yielded high positive predictive values for all individual parameters (gait disturbances 94%, 95% CI 71%-100%, urinary incontinence 100%, 95% CI 66%-100%, and mental status 100%, 95% CI 66%-100%) but negative predictive values were low (< 50%) except for cognitive impairment (85%, 95% CI 55%-98%). This study suggests that a positive ELD-valve system test should be considered a reliable criterion for preoperative selection of shunt-responsive NPH patients. In case of a negative ELD-valve system test

Magnetic-adhesive based valves for microfluidic devices used in low-resource settings.

PubMed

Harper, Jason C; Andrews, Jenna M; Ben, Candice; Hunt, Andrew C; Murton, Jaclyn K; Carson, Bryan D; Bachand, George D; Lovchik, Julie A; Arndt, William D; Finley, Melissa R; Edwards, Thayne L

2016-10-18

Since the introduction of micro total analytical systems (μTASs), significant advances have been made toward development of lab-on-a-chip platforms capable of performing complex biological assays that can revolutionize public health, among other applications. However, use of these platforms in low-resource environments (e.g. developing countries) has yet to be realized as the majority of technologies used to control microfluidic flow rely on off-device hardware with non-negligible size, cost, power requirements and skill/training to operate. In this paper we describe a magnetic-adhesive based valve that is simple to construct and operate, and can be used to control fluid flow and store reagents within a microfluidic device. The design consists of a port connecting two chambers on different planes in the device that is closed by a neodymium disk magnet seated on a thin ring of adhesive. Bringing an external magnet into contact with the outer surface of the device unseats and displaces the valve magnet from the adhesive ring, exposing the port. Using this configuration, we demonstrate on-device reagent storage and on-demand transport and reaction of contents between chambers. This design requires no power or external instrumentation to operate, is extremely low cost ($0.20 materials cost per valve), can be used by individuals with no technical training, and requires only a hand-held magnet to actuate. Additionally, valve actuation does not compromise the integrity of the completely sealed microfluidic device, increasing safety for the operator when toxic or harmful substances are contained within. This valve concept has the potential to simplify design of μTASs, facilitating development of lab-on-a-chip systems that may be practical for use in point-of-care and low-resource settings.

Device landing zone calcification and its impact on residual regurgitation after transcatheter aortic valve implantation with different devices.

PubMed

Seiffert, Moritz; Fujita, Buntaro; Avanesov, Maxim; Lunau, Clemens; Schön, Gerhard; Conradi, Lenard; Prashovikj, Emir; Scholtz, Smita; Börgermann, Jochen; Scholtz, Werner; Schäfer, Ulrich; Lund, Gunnar; Ensminger, Stephan; Treede, Hendrik

2016-05-01

Calcification of the device landing zone is linked to paravalvular regurgitation after transcatheter aortic valve implantation (TAVI). The mechanisms remain incompletely understood and the performance of next-generation transcatheter heart valves (THV) has not been investigated. We evaluated the impact of calcification patterns on residual aortic regurgitation (AR) after TAVI with different THV in patients with severe aortic stenosis. TAVI was performed in 537 patients at two centres. Devices implanted were the Edwards Sapien XT (n = 254), Medtronic CoreValve (n = 123), JenaValve (n = 62), Medtronic Engager (n = 56), and Symetis Acurate (n = 42) prostheses. Calcification of the device landing zone was retrospectively assessed from contrast-enhanced multidetector computed tomography data and correlated with echocardiographic and clinical data. Calcium volumes of the aortic valve and left-ventricular outflow tract were associated with residual AR: No AR, 604 mm(3) (inter-quartile range, IQR 349-916); trace AR, 639 mm(3) (IQR 368-948); mild AR, 710 mm(3) (IQR 412-2078); ≥moderate AR, 1041 mm(3) (IQR 791-1417, P = 0.001). Device landing zone calcium, particularly if located in the left-ventricular outflow tract, and a low cover index were predictive of AR. Differences in the incidence of AR were observed with regard to THV type. Higher calcium volume was associated with the need for post-dilation (n = 134, median 852 [IQR 342-945] vs. 604 [IQR 542-1207] mm(3), P < 0.001). Calcification of the device landing zone, particularly if located inferior to the annulus, was independently associated with residual AR after TAVI with all evaluated THV; however, the incidence of paravalvular leakage differed significantly between the devices implanted. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Glaucoma aqueous drainage device erosion repair with buccal mucous membrane grafts.

PubMed

Rootman, Dan B; Trope, Graham E; Rootman, David S

2009-01-01

Glaucoma aqueous drainage devices are important and effective in the management of recalcitrant glaucoma. One complication of this procedure is erosion and exposure of the tube or plate. Strategies to re-cover glaucoma aqueous drainage devices in such cases have met with variable success. The majority of these interventions use conjunctiva for superficial coverage. However, conjunctiva can be in limited supply, and subject to reerosion. In this report, we discuss the use of oral buccal mucous membrane in combination with a lamellar corneal patch graft for repair of 3 exposed tubes, 2 plates, and a pars plana clip. Mean time to exposure was 4.8 years. Five eyes from 4 patients are presented and the surgical technique is described. Buccal membrane repairs were considered a surgical success in 5 out of 6 cases (83%) with mean follow-up of 1.5 years. We advocate the use of buccal membrane in the repair of glaucoma aqueous drainage device tube/plate erosions in patients for whom local conjunctiva is of variable quality or limited supply. Advantages of this procedure and tissue option are discussed.

Latest-Generation Transcatheter Aortic Valve Replacement Devices and Procedures.

PubMed

Chamandi, Chekrallah; Puri, Rishi; Rodriguez-Gabella, Tania; Rodés-Cabau, Josep

2017-09-01

Transcatheter aortic valve replacement (TAVR) is a well-established treatment for patients with severe symptomatic aortic stenosis who are at high or prohibitive surgical risk. More recently, TAVR has emerged as a valid alternative to surgical aortic valve replacement for treating intermediate-risk patients, and several studies are currently evaluating the role of TAVR in low-risk patients. Transcatheter heart valve (THV) technologies have evolved considerably over time, and important iterations have been implemented in many of the latest-generation devices to (1) reduce the size and improve delivery system properties; (2) improve valve deployment, repositioning, and retrievability; and (3) reduce paravalvular leaks. This article reviews the main characteristics of, and clinical results associated with, the newer-generation THVs while providing an overview of novel TAVR indications. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

AN EVALUATION OF STORM DRAINAGE INLET DEVICES FOR STORMWATER QUALITY TREATMENT

EPA Science Inventory

The activities summarized in this paper included the testing of three representative stormwater control devices that were located at storm drainage inlets. The two proprietary devices utilized screening and filtering (using filter fabric and a coarser mesh). A conventional catchb...

Strong Ferromagnetically-Coupled Spin Valve Sensor Devices for Droplet Magnetofluidics

PubMed Central

Lin, Gungun; Makarov, Denys; Schmidt, Oliver G.

2015-01-01

We report a magnetofluidic device with integrated strong ferromagnetically-coupled and hysteresis-free spin valve sensors for dynamic monitoring of ferrofluid droplets in microfluidics. The strong ferromagnetic coupling between the free layer and the pinned layer of spin valve sensors is achieved by reducing the spacer thickness, while the hysteresis of the free layer is eliminated by the interplay between shape anisotropy and the strength of coupling. The increased ferromagnetic coupling field up to the remarkable 70 Oe, which is five-times larger than conventional solutions, brings key advantages for dynamic sensing, e.g., a larger biasing field giving rise to larger detection signals, facilitating the operation of devices without saturation of the sensors. Studies on the fundamental effects of an external magnetic field on the evolution of the shape of droplets, as enabled by the non-visual monitoring capability of the device, provides crucial information for future development of a magnetofluidic device for multiplexed assays. PMID:26024419

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.

Use of the Heimlich valve in a compact autotransfusion device.

PubMed

Schweitzer, E J; Hauer, J M; Swan, K G; Bresch, J R; Harmon, J W; Graeber, G M

1987-05-01

A compact device which evacuates blood from a hemothorax and facilitates rapid autotransfusion was evaluated in dogs. Experimental hemothorax was established surgically by incising the internal mammary artery through a thoracotomy with the animals under general anesthesia. Postoperatively the blood was drained by one of two methods. In the Heimlich valve group (n = 5), blood was drained by a chest tube through a one-way flutter valve into a collapsible plastic bag. In the Sorenson group (n = 5), blood was drained by a chest tube into the Sorenson Autotransfusion System. Blood from these two groups was then autotransfused. In the control group (n = 5), the drained blood was not autotransfused. Results showed no statistical difference between the two autotransfusion groups in the volume of blood collected, circulating fibrinogen levels, platelet counts, stroma-free hemoglobin levels, prothrombin time, or 51Cr-labeled RBC survival. There was a significant drop in the circulating platelet count, which returned to normal by 24 hours, in both groups of dogs which were autotransfused. We conclude that autotransfusion of blood collected by a compact device which utilizes a Heimlich valve and requires no suction is similar to using the Sorenson Autotransfusion System. It may be safe to use the Heimlich valve to collect blood for autotransfusion in clinical situations, where its qualities of simplicity, portability and a minimum requirement for storage space are desirable.

Assessment of Cardiac Device Position on Supine Chest Radiograph in the ICU: Introduction and Applicability of the Aortic Valve Location Ratio.

PubMed

Ouweneel, Dagmar M; Sjauw, Krischan D; Wiegerinck, Esther M A; Hirsch, Alexander; Baan, Jan; de Mol, Bas A J M; Lagrand, Wim K; Planken, R Nils; Henriques, José P S

2016-10-01

The use of intracardiac assist devices is expanding, and correct position of these devices is required for optimal functioning. The aortic valve is an important landmark for positioning of those devices. It would be of great value if the device position could be easily monitored on plain supine chest radiograph in the ICU. We introduce a ratio-based tool for determination of the aortic valve location on plain supine chest radiograph images, which can be used to evaluate intracardiac device position. Retrospective observational study. Large academic medical center. Patients admitted to the ICU and supported by an intracardiac assist device. We developed a ratio to determine the aortic valve location on supine chest radiograph images. This ratio is used to assess the position of a cardiac assist device and is compared with echocardiographic findings. Supine anterior-posterior chest radiographs of patients with an aortic valve prosthesis (n = 473) were analyzed to determine the location of the aortic valve. We calculated several ratios with the potential to determine the position of the aortic valve. The aortic valve location ratio, defined as the distance between the carina and the aortic valve, divided by the thoracic width, was found to be the best performing ratio. The aortic valve location ratio determines the location of the aortic valve caudal to the carina, at a distance of 0.25 ± 0.05 times the thoracic width for male patients and 0.28 ± 0.05 times the thoracic width for female patients. The aortic valve location ratio was validated using CT images of patients with angina pectoris without known valvular disease (n = 95). There was a good correlation between cardiac device position (Impella) assessed with the aortic valve location ratio and with echocardiography (n = 53). The aortic valve location ratio enables accurate and reproducible localization of the aortic valve on supine chest radiograph. This tool is easily applicable and can be used for

A microfluidic device with multi-valves system to enable several simultaneous exposure tests on Caenorhabditis elegans

NASA Astrophysics Data System (ADS)

Jung, Jaehoon; Nakajima, Masahiro; Masaru, Takeuchi; Huang, Qiang; Fukuda, Toshio

2014-03-01

In this paper, we report on a microfluidic device with a multi-valve system to conduct several exposure tests on Caenorhabditis elegans (C. elegans) simultaneously. It has pneumatic valves and no-moving-parts (NMP) valves. An NMP valve is incorporated with a chamber and enables the unidirectional movement of C. elegans in the chamber; once worms are loaded into the chamber, they cannot exit, regardless of the flow direction. To demonstrate the ability of the NMP valve to handle worms, we made a microfluidic device with three chambers. Each chamber was used to expose worms to Cd and Cu solutions, and K-medium. A pair of electrodes was installed in the device and the capacitance in-between the electrode was measured. When a C. elegans passed through the electrodes, the capacitance was changed. The capacitance change was proportional to the body volume of the worm, thus the body volume change by the heavy metal exposure was measured in the device. Thirty worms were divided into three groups and exposed to each solution. We confirmed that the different solutions induced differences in the capacitance changes for each group. These results indicate that our device is a viable method for simultaneously analyzing the effect of multiple stimuli on C. elegans.

Rothia mucilaginosa Prosthetic Device Infections: a Case of Prosthetic Valve Endocarditis

PubMed Central

Tokarczyk, Mindy J.; Jungkind, Donald; DeSimone, Joseph A.

2013-01-01

Rothia mucilaginosa is increasingly recognized as an emerging opportunistic pathogen associated with prosthetic device infections. Infective endocarditis is one of the most common clinical presentations. We report a case of R. mucilaginosa prosthetic valve endocarditis and review the literature of prosthetic device infections caused by this organism. PMID:23467598

Arterial Pulsations cannot Drive Intramural Periarterial Drainage: Significance for Aβ Drainage

PubMed Central

Diem, Alexandra K.; MacGregor Sharp, Matthew; Gatherer, Maureen; Bressloff, Neil W.; Carare, Roxana O.; Richardson, Giles

2017-01-01

Alzheimer's Disease (AD) is the most common form of dementia and to date there is no cure or efficient prophylaxis. The cognitive decline correlates with the accumulation of amyloid-β (Aβ) in the walls of capillaries and arteries. Our group has demonstrated that interstitial fluid and Aβ are eliminated from the brain along the basement membranes of capillaries and arteries, the intramural periarterial drainage (IPAD) pathway. With advancing age and arteriosclerosis, the stiffness of arterial walls, this pathway fails in its function and Aβ accumulates in the walls of arteries. In this study we tested the hypothesis that arterial pulsations drive IPAD and that a valve mechanism ensures the net drainage in a direction opposite to that of the blood flow. This hypothesis was tested using a mathematical model of the drainage mechanism. We demonstrate firstly that arterial pulsations are not strong enough to produce drainage velocities comparable to experimental observations. Secondly, we demonstrate that a valve mechanism such as directional permeability of the IPAD pathway is necessary to achieve a net reverse flow. The mathematical simulation results are confirmed by assessing the pattern of IPAD in mice using pulse modulators, showing no significant alteration of IPAD. Our results indicate that forces other than the cardiac pulsations are responsible for efficient IPAD. PMID:28883786

Multi-step Variable Height Photolithography for Valved Multilayer Microfluidic Devices.

PubMed

Brower, Kara; White, Adam K; Fordyce, Polly M

2017-01-27

Microfluidic systems have enabled powerful new approaches to high-throughput biochemical and biological analysis. However, there remains a barrier to entry for non-specialists who would benefit greatly from the ability to develop their own microfluidic devices to address research questions. Particularly lacking has been the open dissemination of protocols related to photolithography, a key step in the development of a replica mold for the manufacture of polydimethylsiloxane (PDMS) devices. While the fabrication of single height silicon masters has been explored extensively in literature, fabrication steps for more complicated photolithography features necessary for many interesting device functionalities (such as feature rounding to make valve structures, multi-height single-mold patterning, or high aspect ratio definition) are often not explicitly outlined. Here, we provide a complete protocol for making multilayer microfluidic devices with valves and complex multi-height geometries, tunable for any application. These fabrication procedures are presented in the context of a microfluidic hydrogel bead synthesizer and demonstrate the production of droplets containing polyethylene glycol (PEG diacrylate) and a photoinitiator that can be polymerized into solid beads. This protocol and accompanying discussion provide a foundation of design principles and fabrication methods that enables development of a wide variety of microfluidic devices. The details included here should allow non-specialists to design and fabricate novel devices, thereby bringing a host of recently developed technologies to their most exciting applications in biological laboratories.

Case Series: Keratolimbal Allograft as a Patch Graft for Glaucoma Drainage Devices.

PubMed

Ahmed, Sarah F; Schmutz, Mason; Mosaed, Sameh

2017-09-01

Tube exposure remains one of the most common complications after glaucoma drainage device (GDD) implantation, despite various types of patch grafts available today. We present a 4 patient case series following the effectivity of the keratolimbal allograft (KLAL) as a patch graft for cases of tube exposure. Given its inherent population of stem cells, our hypothesis was that this highly replicative, biological tissue would provide an adequate means of glaucoma tube coverage. The subset of patients chosen for the KLAL patch graft all had a history of abnormally scarred conjunctiva or thin sclera. The aim of utilizing the KLAL patch with its associated donor conjunctival and scleral ring was also to provide additional reinforcement and adequate tube coverage in the setting of compromised native tissue. Four patients comprised of 2 males and 2 females with a minimum postoperative period of 12 months. All GDDs were initially implanted with a limbal-based incision using either Ahmed glaucoma valve or Baerveldt drainage implant. Three of the 4 patients received the KLAL patch graft after tube exposure with scleral patch graft and 1 patient received KLAL as the primary graft during initial tube placement. Two of the 4 eyes experienced tube re-exposure postoperatively at 2 and 3 months, respectively. Both of these cases had a history of prior tube exposure after scleral patch graft and both were tubes placed in the pars plana. Interestingly, the patients with failed grafts were younger with a history of more ocular surgeries as compared with the patients with graft viable eyes. Through our case series, we found that the KLAL utilized as a patch graft over GDD tubes has the potential for favorable outcomes in certain subtypes of eyes. Although further large scale investigation will be necessary to better define the risk factors associated with graft failure, proving the graft's viability is a crucial first step.

Controlling Capillary-Driven Fluid Transport in Paper-Based Microfluidic Devices Using a Movable Valve.

PubMed

Li, Bowei; Yu, Lijuan; Qi, Ji; Fu, Longwen; Zhang, Peiqing; Chen, Lingxin

2017-06-06

This paper describes a novel strategy for fabricating the movable valve on paper-based microfluidic devices to manipulate capillary-driven fluids. The movable valve fabrication is first realized using hollow rivets as the holding center to control the paper channel in different layer movement that results in the channel's connection or disconnection. The relatively simple valve fabrication procedure is robust, versatile, and compatible with microfluidic paper-based analytical devices (μPADs) with differing levels of complexity. It is remarkable that the movable valve can be convenient and free to control fluid without the timing setting, advantages that make it user-friendly for untrained users to carry out the complex multistep operations. For the performance of the movable valve to be verified, several different designs of μPADs were tested and obtained with satisfactory results. In addition, in the proof-of-concept enzyme-linked immunosorbent assay experiments, we demonstrate the use of these valves in μPADs for the successful analysis of samples of carcino-embryonic antigen, showing good sensitivity and reproducibility. We hope this technique will open new avenues for the fabrication of paper-based valves in an easily adoptable and widely available way on μPADs and provide potential point-of-care applications in the future.

Use of Ice-Nucleating Proteins To Improve the Performance of Freeze-Thaw Valves in Microfluidic Devices.

PubMed

Gaiteri, Joseph C; Henley, W Hampton; Siegfried, Nathan A; Linz, Thomas H; Ramsey, J Michael

2017-06-06

Currently, reliable valving on integrated microfluidic devices fabricated from rigid materials is confined to expensive and complex methods. Freeze-thaw valves (FTVs) can provide a low cost, low complexity valving mechanism, but reliable implementation of them has been greatly hindered by the lack of ice nucleation sites within the valve body's small volume. Work to date has required very low temperatures (on the order of -40 °C or colder) to induce freezing without nucleation sites, making FTVs impractical due to instrument engineering challenges. Here, we report the use of ice-nucleating proteins (INPs) to induce ice formation at relatively warm temperatures in microfluidic devices. Microfluidic channels were filled with buffers containing femtomolar INP concentrations from Pseudomonas syringae. The channels were cooled externally with simple, small-footprint Peltier thermoelectric coolers (TECs), and the times required for channel freezing (valve closure) and thawing (valve opening) were measured. Under optimized conditions in plastic chips, INPs made sub-10 s actuations possible at TEC temperatures as warm as -13 °C. Additionally, INPs were found to have no discernible inhibitory effects in model enzyme-linked immunosorbent assays or polymerase chain reactions, indicating their compatibility with microfluidic systems that incorporate these widely used bioassays. FTVs with INPs provide a much needed reliable valving scheme for rigid plastic devices with low complexity, low cost, and no moving parts on the device or instrument. The reduction in freeze time, accessible actuation temperatures, chemical compatibility, and low complexity make the implementation of compact INP-based FTV arrays practical and attractive for the control of integrated biochemical assays.

Cerebrospinal Fluid Lumbar Tapping Utilization for Suspected Ventriculoperitoneal Shunt Under-Drainage Malfunctions

PubMed Central

Lee, Jong-Beom; Ahn, Ho-Young; Lee, Hong-Jae; Yang, Ji-Ho; Yi, Jin-Seok; Lee, Il-Woo

2017-01-01

Objective The diagnosis of shunt malfunction can be challenging since neuroimaging results are not always correlated with clinical outcomes. The purpose of this study was to evaluate the efficacy of a simple, minimally invasive cerebrospinal fluid (CSF) lumbar tapping test that predicts shunt under-drainage in hydrocephalus patients. Methods We retrospectively reviewed the clinical and radiological features of 48 patients who underwent routine CSF lumbar tapping after ventriculoperitoneal shunt (VPS) operation using a programmable shunting device. We compared shunt valve opening pressure and CSF lumbar tapping pressure to check under-drainage. Results The mean pressure difference between valve opening pressure and CSF lumbar tapping pressure of all patients were 2.21±24.57 mmH2O. The frequency of CSF lumbar tapping was 2.06±1.26 times. Eighty five times lumbar tapping of 41 patients showed that their VPS function was normal which was consistent with clinical improvement and decreased ventricle size on computed tomography scan. The mean pressure difference in these patients was −3.69±19.20 mmH2O. The mean frequency of CSF lumbar tapping was 2.07±1.25 times. Fourteen cases of 10 patients revealed suspected VPS malfunction which were consistent with radiological results and clinical symptoms, defined as changes in ventricle size and no clinical improvement. The mean pressure difference was 38.07±23.58 mmH2O. The mean frequency of CSF lumbar tapping was 1.44±1.01 times. Pressure difference greater than 35 mmH2O was shown in 2.35% of the normal VPS function group (2 of 85) whereas it was shown in 64.29% of the suspected VPS malfunction group (9 of 14). The difference was statistically significant (p=0.000001). Among 10 patients with under-drainage, 5 patients underwent shunt revision. The causes of the shunt malfunction included 3 cases of proximal occlusion and 2 cases of distal obstruction and valve malfunction. Conclusion Under-drainage of CSF should be

Cerebrospinal Fluid Lumbar Tapping Utilization for Suspected Ventriculoperitoneal Shunt Under-Drainage Malfunctions.

PubMed

Lee, Jong-Beom; Ahn, Ho-Young; Lee, Hong-Jae; Yang, Ji-Ho; Yi, Jin-Seok; Lee, Il-Woo

2017-01-01

The diagnosis of shunt malfunction can be challenging since neuroimaging results are not always correlated with clinical outcomes. The purpose of this study was to evaluate the efficacy of a simple, minimally invasive cerebrospinal fluid (CSF) lumbar tapping test that predicts shunt under-drainage in hydrocephalus patients. We retrospectively reviewed the clinical and radiological features of 48 patients who underwent routine CSF lumbar tapping after ventriculoperitoneal shunt (VPS) operation using a programmable shunting device. We compared shunt valve opening pressure and CSF lumbar tapping pressure to check under-drainage. The mean pressure difference between valve opening pressure and CSF lumbar tapping pressure of all patients were 2.21±24.57 mmH 2 O. The frequency of CSF lumbar tapping was 2.06±1.26 times. Eighty five times lumbar tapping of 41 patients showed that their VPS function was normal which was consistent with clinical improvement and decreased ventricle size on computed tomography scan. The mean pressure difference in these patients was -3.69±19.20 mmH 2 O. The mean frequency of CSF lumbar tapping was 2.07±1.25 times. Fourteen cases of 10 patients revealed suspected VPS malfunction which were consistent with radiological results and clinical symptoms, defined as changes in ventricle size and no clinical improvement. The mean pressure difference was 38.07±23.58 mmH 2 O. The mean frequency of CSF lumbar tapping was 1.44±1.01 times. Pressure difference greater than 35 mmH 2 O was shown in 2.35% of the normal VPS function group (2 of 85) whereas it was shown in 64.29% of the suspected VPS malfunction group (9 of 14). The difference was statistically significant ( p =0.000001). Among 10 patients with under-drainage, 5 patients underwent shunt revision. The causes of the shunt malfunction included 3 cases of proximal occlusion and 2 cases of distal obstruction and valve malfunction. Under-drainage of CSF should be suspected if CSF lumbar tapping

Percutaneous Tricuspid Valve Regurgitation Repair With the MitraClip Device Using an Edge-to-Edge Bicuspidization Technique.

PubMed

Gafoor, Sameer; Petrescu, O Madalina; Lehr, Eric J; Puls, Charles; Zhang, Ming; Petersen, John L; Olsen, John V; Penev, Irina; Agrawal, Mayank; Sharma, Rahul; Barnhart, Glenn

2017-03-01

Patients who present with both severe mitral and tricuspid regurgitation who are symptomatic despite optimal medical therapy and at prohibitive risk for surgery pose a significant therapeutic challenge. The MitraClip device (Abbott Vascular) is approved for percutaneous mitral valve repair in high-risk and non-operative patients, and has also been used for tricuspid valve repair. Imaging support for percutaneous edge-to-edge tricuspid valve repair has not been reported and is a vital part of the procedure. Here, we present a periprocedural imaging strategy for percutaneous tricuspid valve repair with the MitraClip device using a bicuspidization technique.

Exchange biased and closed-flux pseudo spin-valve materials, device applications, and electrical reliability

NASA Astrophysics Data System (ADS)

Bae, Seongtae

Since giant magnetoresistance (GMR) and tunneling magnetoresistance (TMR) spinvalve effects were developed for the last two decades after discovered, world wide researches on applying these effects for various kinds of solid state active devices has provided a strong impact on challenging new functional micro-magnetoelectronic devices. In particular, recently developed nano-structured magnetic spin-valve thin film materials for spin-electronic devices are now considered as building blocks of state-of-the-art electronic engineering. This research has been concentrated on developing and designing magneto-electronic solid state devices with high thermal and electrical stability using an alpha-Fe 2O3 and NiO oxide anti-ferromagnetic exchange biased GMR bottom spin-valves (BSV), NiFe/Cu/Co and NiFe/Cu/CoFe based closed-flux metallic pseudo spin-valves, and PtMn exchange biased TMR spin-valves. The category covering this research is divided into four main research steps. First is to investigate exchange bias coupling characteristics of alpha-Fe2 O3 and NiO oxide Anti-ferromagnetic materials (AF)/Ferromagnetic (F) layer systems for optimizing exchange biased BSV and to study magnetic properties of various kinds of magnetic thin films including single through multi-layered structures for the fundamental research on NiFe/Cu/Co and NiFe/Cu/CoFe closed-flux metallic pseudo spin-valves. Second is to develop and improve new kinds of BSVs and closed-flux metallic spinvalves by controlling process parameters in terms of crystalline orientation texture of AF and F layers, interfacial surface roughness, grain size (its size distribution), chemical composition, and kinetics of sputtering film growth. Third is to design, to fabricate, and to investigate the magnetic and electrical properties of magneto-electronic devices as well as their applications such as GMR magnetoresistive random access memory (MRAM), GMR read head, TMR read head, and new kinds of GMR solid state devices, which

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.

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.

Magnetotransport properties of a few-layer graphene-ferromagnetic metal junctions in vertical spin valve devices

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

Entani, Shiro, E-mail: entani.shiro@jaea.go.jp; Naramoto, Hiroshi; Sakai, Seiji

2015-05-07

Magnetotransport properties were studied for the vertical spin valve devices with two junctions of permalloy electrodes and a few-layer graphene interlayer. The graphene layer was directly grown on the bottom electrode by chemical vapor deposition. X-ray photoelectron spectroscopy showed that the permalloy surface fully covered with a few-layer graphene is kept free from oxidation and contamination even after dispensing and removing photoresist. This enabled fabrication of the current perpendicular to plane spin valve devices with a well-defined interface between graphene and permalloy. Spin-dependent electron transport measurements revealed a distinct spin valve effect in the devices. The magnetotransport ratio was 0.8%more » at room temperature and increased to 1.75% at 50 K. Linear current-voltage characteristics and resistance increase with temperature indicated that ohmic contacts are realized at the relevant interfaces.« less

Persistent hydrocephalus due to postural activation of a ventricular shunt anti-gravity device.

PubMed

Craven, Claudia L; Toma, Ahmed K; Watkins, Laurence D

2017-03-01

The ever present need to balance over drainage with under drainage in hydrocephalus has required innovations including adjustable valves with antigravity devices. These are activated in the vertical position to prevent siphoning. We describe a group of bedridden patients who presented with unexplained under drainage caused by activation of antigravity shunt components produced by peculiar head/body position. Retrospective single centre case series of hydrocephalus patients, treated with ventriculo-peritoneal (VP) shunt insertion between April 2014 - February 2016. These patients presented with clinical and radiological under drainage syndrome. Medical notes were reviewed for clinical picture and outcome. Radiological studies were reviewed assessing shunt placement and ventricular size. Seven patients presented with clinical and radiological under drainage syndrome. A consistent posturing of long term hyper-flexion of the neck whilst lying supine was observed. All patients had similar shunt construct (adjustable Miethke ProGAV valve and shunt assistant anti-gravity component). In each of those patients a hypothesis was formulated that neck flexion was activating the shunt assistance anti-gravity component in supine position. Five patients underwent shunt revision surgery removing the shunt assistant device from the cranium and adding an anti-gravity component to the shunt system at the chest. One had the shunt assistant completely removed and one patient was managed conservatively with mobilisation. All patients had clinical and radiological improvement. Antigravity shunt components implanted cranially in bedridden hydrocephalus patients will produce underdrainage due to head flexion induced anti-gravity device activation. In these patients, anti-gravity devices should be placed at the chest. Alternatively, special nursing attention should be paid to head-trunk angle. Copyright © 2016 Elsevier Ltd. All rights reserved.

Left Ventricular Assist Device Implantation with Concomitant Aortic Valve and Ascending Aortic Replacement.

PubMed

Huenges, Katharina; Panholzer, Bernd; Cremer, Jochen; Haneya, Assad

2018-01-01

Left ventricular assist device (LVAD) is nowadays a routine therapy for patients with advanced heart failure. We present the case of a 74-year-old male patient who was admitted to our center with terminal heart failure in dilated cardiomyopathy and ascending aortic aneurysm with aortic valve regurgitation. The LVAD implantation with simultaneous aortic valve and supracoronary ascending aortic replacement was successfully performed.

Cell and protein adhesion studies in glaucoma drainage device development

PubMed Central

The, A

1999-01-01

AIM—To examine in vitro whether phosphorylcholine coating of poly(methylmethacrylate) can reduce the adhesion of fibrinogen, fibrin, human scleral fibroblast and macrophage compared with current biomaterials used in the construction of glaucoma drainage devices.
METHODS—Sample discs (n=6) of poly(methylmethacrylate), silicone, polypropylene, PTFE, and phosphorylcholine coated poly(methylmethacrylate) were seeded with fibrinogen, fibrin, fibroblast, and macrophages and incubated for variable lengths of time. The quantification was performed using radioactivity, spectrophotometry, ATP dependent luminometry, and immunohistochemistry respectively.
RESULTS—Fibrinogen and fibrin adhesion to phosphorylcholine coated poly(methylmethacrylate) were significantly lower than PMMA (p=0.004). Phosphorylcholine coating of poly(methylmethacrylate) also significantly reduced the adhesion of human scleral fibroblast (p=0.002) and macrophage (p=0.01) compared with PMMA. All the other biomaterials showed either similar or insignificantly different levels of adhesion to all the proteins and cells tested compared with PMMA.
CONCLUSION—Phosphorylcholine coating is a new material technology that offers considerable promise in the field of glaucoma drainage device development.

 PMID:10502580

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.

Experimental flow studies in glaucoma drainage device development.

PubMed

2001-10-01

(I) To examine whether small holes produced by 248 nm excimer laser ablation in a polymer substrate could consistently produce a pressure drop in the desired target range (5-15 mm Hg) at physiological aqueous flow rates for use as an internal flow restrictor in a glaucoma drainage device, and (ii) to investigate whether external leakage could be reduced in comparison with conventional tube and plate glaucoma drainage devices by redesigning the exterior cross sectional shape of the portion contained within the sclerocorneal tunnel. Single holes with target diameters of 10 microm, 15 microm, 20 microm, and 25 microm were drilled using a 248 nm excimer laser in sample discs (n=6 at each diameter) punched from a 75 microm thick polyimide sheet. Sample discs were tested in a flow rig designed to measure the pressure drop across the discs. Using filtered, degassed water at a flow rate of 1.4 microl/min repeated flow measurements were taken (n=6) for each disc. After flow testing, all discs were imaged using a scanning electron microscope and the dimensions of each hole were derived using image analysis software. In the external leakage study, corneoscleral buttons (n=13) were prepared from cadaver pig eyes and mounted on an artificial anterior chamber infused with Tyrode solution. After the pressure had stabilised, standard occluded silicone tube implants were inserted through 23 gauge needle stab incisions at the limbus. These were compared against prototype PMMA implants with a novel shape profile inserted through 1.15 mm width microvitreoretinal (MVR) stab incisions at the limbus. The infusion rate was maintained and a second pressure measurement was taken when the pressure had stabilised. The difference between the first and second pressure measurement was then compared, as an index of external leakage. Ablated tubes were found to have a near perfect circular outline on both the entry and exit side. The observed pressure drops across the ablated sample discs at each

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.

Left Ventricular Assist Device Implantation with Concomitant Aortic Valve and Ascending Aortic Replacement

PubMed Central

Panholzer, Bernd; Cremer, Jochen; Haneya, Assad

2018-01-01

Left ventricular assist device (LVAD) is nowadays a routine therapy for patients with advanced heart failure. We present the case of a 74-year-old male patient who was admitted to our center with terminal heart failure in dilated cardiomyopathy and ascending aortic aneurysm with aortic valve regurgitation. The LVAD implantation with simultaneous aortic valve and supracoronary ascending aortic replacement was successfully performed. PMID:29552039

A valved hepatic portoduodenal intestinal conduit for biliary atresia.

PubMed

Tanaka, K; Shirahase, I; Utsunomiya, H; Katayama, T; Uemoto, S; Asonuma, K; Inomata, Y; Ozawa, K

1991-03-01

Forty-six consecutive patients with biliary atresia were operated on at our institution during the 11-year period between 1978 and 1989. Their ages at operation ranged from 18 to 153 days (mean, 59 days). After dissecting the porta hepatis structures by Kasai operation, a biliointestinal anastomosis was constructed with a valved hepatic portoduodenal intestinal conduit in all cases. The intestinal valve is an intussuscepted muscular valve. Valvular function was examined radiologically. The upper gastrointestinal series demonstrated no reflux of contrast material into the conduit proximal to the valve and liver scintigraphy demonstrated that radioactive isotope drained readily into the duodenum through the valve. Thirty-nine of the forty-six patients (85%) had bile drainage after initial operation. At present 30 patients (65%) are alive without jaundice, 6 (13%) are alive with jaundice, and 10 (22%) are dead. The 5-year jaundice-free survival rate was 64%. Cholangitis occurred in 9 of 39 patients (23%) who had obtained apparent bile drainage: 5 had tractable cholangitis and 4 had refractory cholangitis. Reoperation restored bile flow in 2 of 8 patients who abruptly ceased to have bile drainage without cholangitis. In conclusion, with a valved hepatic portoduodenal intestinal conduit, the incidence of cholangitis was decreased, its medical control became easier, and the survival rate was improved.

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

30 CFR 18.28 - Devices for pressure relief, ventilation, or drainage.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Devices for pressure relief, ventilation, or drainage. 18.28 Section 18.28 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES...

Experimentally validated quantitative linear model for the device physics of elastomeric microfluidic valves

NASA Astrophysics Data System (ADS)

Kartalov, Emil P.; Scherer, Axel; Quake, Stephen R.; Taylor, Clive R.; Anderson, W. French

2007-03-01

A systematic experimental study and theoretical modeling of the device physics of polydimethylsiloxane "pushdown" microfluidic valves are presented. The phase space is charted by 1587 dimension combinations and encompasses 45-295μm lateral dimensions, 16-39μm membrane thickness, and 1-28psi closing pressure. Three linear models are developed and tested against the empirical data, and then combined into a fourth-power-polynomial superposition. The experimentally validated final model offers a useful quantitative prediction for a valve's properties as a function of its dimensions. Typical valves (80-150μm width) are shown to behave like thin springs.

Single-centre experience with next-generation devices for transapical aortic valve implantation.

PubMed

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

2015-01-01

Transcatheter aortic valve implantation (TAVI) has become an established procedure in patients with aortic stenosis and high surgical risk. Experience with first-generation transcatheter heart valves (THVs) is broad but limitations, e.g. paravalvular regurgitation, have been demonstrated. Much hope rests on the recently Conformité Européenne mark approved next-generation devices to improve results in these patients. However, apart from the initial approval studies, clinical data with these new devices are still scarce. We aimed to assess short-term outcomes of 200 consecutive patients who underwent transapical TAVI with next-generation THV at our institution. Transapical TAVI was performed in 200 consecutive patients 80.5±6.7 years old (38.5% female) at high surgical risk (log EuroSCORE 20.2±16.5%). Devices implanted were the Engager (Medtronic, Inc., Minneapolis, MN, USA; n=50), JenaValve (JenaValve Technology, Munich, Germany; n=88) and Symetis Acurate (Symetis SA, Ecublens, Switzerland; n=62) THV that were selected by the heart team on an individual basis. Data at baseline, during the procedure and follow-up were analysed according to standardized Valve Academic Research Consortium end points. Median follow-up was 219 days. Implantation was successful in 96.5% of cases. Valve function improved significantly with an increase in effective orifice area from 0.8±0.4 to 1.8±0.3 cm2 and a reduction in mean transvalvalvular gradients from 34.0±17.0 to 11.2±5.4 mmHg. Paravalvular regurgitation was none or trace in 70.3% of patients, Grade 1 in 26.1%, and Grade 2 in 3.5%. No patients developed aortic regurgitation>Grade 2. Major access site complications occurred in 6.5%, major stroke in 1.5% and stage-3 kidney injury in 2.5% of patients. A permanent pacemaker was implanted in 20.5% of patients overall and in 8.0% for a complete heart block. At 30-day follow-up 72.8% of patients were in New York Heart Association class I or II (10.5% at baseline). Overall

40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2014 CFR

2014-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices in...

40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2013 CFR

2013-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices in...

40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2012 CFR

2012-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices in...

40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2011 CFR

2011-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices in...

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.

Complications and 2-year valve survival following Ahmed valve implantation during the first 2 years of life.

PubMed

Almobarak, F; Al-Mobarak, F; Khan, A O

2009-06-01

To report complications and 2-year valve survival following Ahmed valve implantation during the first 2 years of life. Retrospective institutional case series. Forty-two eyes of 36 patients with Ahmed valve implantation (without prior drainage device surgery) during the first 2 years of life and 2 years' postsurgical follow-up were identified. Most eyes had primary congenital glaucoma (28/42, 66.7%), aphakic glaucoma (5/42, 11.9%) or Peters anomaly (5/42, 11.9%). All but three eyes had prior ocular surgery. Surgery was at a mean age of 11.83 months (m) (SD 5.63). The most common significant postoperative complications were tube malpositioning requiring intervention (11/42, 26.2%), endophthalmitis (3/42, 7.1%; one with tube exposure) and retinal detachment (3/42, 7.1%). Thirty-six eyes (85.8%) required resumption of antiglaucoma medications to maintain intraocular pressure (IOP) < or =22 mm Hg a mean of 7.2 m (SD 6.8) postoperatively. Cumulative probabilities of valve survival (IOP< or =22 mm Hg with or without medication) by Kaplan-Meier analysis were 73.8% and 63.3% at 12 months and 24 months, respectively. Postoperative tube malpositioning that required surgical revision was common in this age group. Infectious endophthalmitis and retinal detachment are known potential complications following any incisional surgery for advanced buphthalmos; however, tube exposure is a unique potential problem following aqueous shunt implantation that can lead to intraocular infection. Cumulative valve survival 2 years following implantation was 63.3%.

[Development of a glaucoma microstent with drainage into the suprachoroidal space: fluid mechanical model approach].

PubMed

Guthoff, R F; Schmidt, W; Buss, D; Schultze, C; Ruppin, U; Stachs, O; Sternberg, K; Klee, D; Chichkov, B; Schmitz, K-P

2009-09-01

The purpose of this study was to develop a microstent with valve function, which normalizes the intraocular pressure (IOP) and drains into the suprachoroidal space. In comparison to the subconjunctival space the suprachoroidal space is attributed with less fibroblast colonization and activity. Different glaucoma drainage devices were idealized as tubes and the flow rates were calculated according to Hagen-Poiseuille. The dimensions of the ideal glaucoma implant were modified with respect to an aqueous humor production of 2 microl/min and the different outflow pathways. Specific components of glaucoma drainage devices at the inlet and outlet were not included. The volume flow calculation of the tested glaucoma implants showed that the dimensions of all lumina were too large to prevent postoperative hypotension. A maximum inner tube diameter of 53 microm was calculated for drainage into the suprachoroidal space based on an intra-ocular pressure (IOP) of 20 mmHg. The glaucoma microstent has to guarantee an aqueous humor flow for physiological IOP. An increase of IOP has to be regulated to physiological pressure conditions by the microvalve.

40 CFR 265.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2011 CFR

2011-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief...

40 CFR 265.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2012 CFR

2012-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief...

40 CFR 265.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2013 CFR

2013-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief...

40 CFR 265.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2014 CFR

2014-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief...

[Extracorporeal ventriculoatrial shunt with the use of one-way ball valve].

PubMed

Kubo, Shigeki; Takimoto, Hiroshi; Hosoi, Kazuki; Toyota, Shingo; Takakura, Shuji; Hayashi, Yasuhiro; Ueno, Masato; Morisako, Toshitaka; Karasawa, Jun; Ninaga, Hideo; Yoshimine, Toshiki

2002-04-01

We developed a simple system of an "extracorporeal" ventriculoatrial (VA) shunt using a one-way ball valve (Acty valve II, Kaneka Medix) to release the patient from postoperative constraint during the ventricular drainage. The system is constructed in such a way that the ventricular drainage tube is connected to the central venous catheter via a one-way valve. The CSF is regulated by using the valve and is diverted into the systemic circulation as in the conventional ventriculoatrial shunt. After 2 or 3 weeks of CSF diversion through the extracorporeal VA shunt, a ventriculoperitoneal shunt is placed if hydrocephalus is apparent by temporary occlusion of the system. We applied this system to 4 patients with hydrocephalus, and we found it useful and free from adverse effects. The patient was freed from physical constraint involved in conventional ventricular drainage and an effective program of early rehabilitation was able to be started.

Low permanent pacemaker rates following Lotus device implantation for transcatheter aortic valve replacement due to modified implantation protocol.

PubMed

Krackhardt, Florian; Kherad, Behrouz; Krisper, Maximilian; Pieske, Burkert; Laule, Michael; Tschöpe, Carsten

2017-01-01

Conduction disturbances requiring permanent pacemaker implantation following transcatheter aortic valve replacement (TAVR) are a common problem. Pacemaker implantation rates after TAVR appear to be higher compared to conventional aortic valve replacement. The aim of this study was to analyze whether a high annulus implantation conveys the benefit of a decreased rate of permanent pacemaker implantation while being safe and successful according to Valve Academic Research Consortium 2 (VARC2)-criteria. A total of 23 patients with symptomatic severe aortic valve stenosis, an aortic annulus of 19-27 mm and at high risk for surgery were treated with the Lotus valve. In all patients the valve was implanted in a high annulus position via femoral access. The primary device performance endpoint was VARC2-defined device success after 30 days and the primary safety endpoint was the need for permanent pacemaker implantation. The mean age was 73.23 ± 7.65 years, 46% were female, 38% were New York Heart Association class III/IV at baseline. Thirty-day follow-up data were available for all patients. The VARC2-defined device success rate after 30 days was 22/23 (96%). 2/21 (10%) patients required a newly implanted pacemaker due to 3rd degree atrioventricular block. 25% of the patients developed a new left bundle branch block after valvuloplasty or device implantation. 21 of the 23 patients (96%) had no other signs of conduction disturbances after 30 days. The approach of the modified implantation technique of Lotus TAVR device was safe and effective. The incidence of need for a permanent pacemaker following TAVR could be significantly reduced due to adopted implantation protocol.

40 CFR 265.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid service...

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.

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.

Intracranial Pressure-Guided Shunt Valve Adjustments with the Miethke Sensor Reservoir.

PubMed

Antes, Sebastian; Stadie, Axel; Müller, Simon; Linsler, Stefan; Breuskin, David; Oertel, Joachim

2018-01-01

Telemetric intracranial pressure (ICP) monitoring seems to be a promising therapy-supporting option in shunt-treated patients. Benefits become obvious when headaches are unspecific and clinical symptoms cannot be related to possible overdrainage or underdrainage. In this study, we evaluated a new telemetric device to individually adjust shunt valves according to ICP measurements. Between December 2015 and November 2016, 25 patients with suspected suboptimal shunt valve settings underwent insertion of a telemetric ICP sensor (Sensor Reservoir; Christoph Miethke, Potsdam, Germany). Over a 1-year period, a total of 183 telemetric ICP measurements and 85 shunt valve adjustments were carried out. Retrospective statistic analyses focused on valve adjustments, ICP values, and clinical outcomes. ICP-guided valve adjustments positively changed the clinical state in 18 out of 25 patients. Clinical improvement over time was associated with significant changes of the valve settings and ICP values. Interestingly, a therapeutically normalized ICP profile was not automatically associated with clinical improvement. The Sensor Reservoir is an important and valuable tool for shunt-treated patients suffering from drainage-related problems. The possibility to simultaneously recognize and solve shunt problems represents the decisive advantage. Nevertheless, measurements with the Sensor Reservoir did not allow for the determination of default valve settings or universal target ICP values. Copyright © 2017 Elsevier Inc. All rights reserved.

Biomedical Impact in Implantable Devices-The Transcatheter Aortic Valve as an example

NASA Astrophysics Data System (ADS)

Anastasiou, Alexandros; Saatsakis, George

2015-09-01

Objective: To update of the scientific community about the biomedical engineering involvement in the implantable devices chain. Moreover the transcatheter Aortic Valve (TAV) replacement, in the field of cardiac surgery, will be analyzed as an example of contemporary implantable technology. Methods: A detailed literature review regarding biomedical engineers participating in the implantable medical product chain, starting from the design of the product till the final implantation technique. Results: The scientific role of biomedical engineers has clearly been established. Certain parts of the product chain are implemented almost exclusively by experienced biomedical engineers such as the transcatheter aortic valve device. The successful professional should have a multidisciplinary knowledge, including medicine, in order to pursue the challenges for such intuitive technology. This clearly indicates that biomedical engineers are among the most appropriate scientists to accomplish such tasks. Conclusions: The biomedical engineering involvement in medical implantable devices has been widely accepted by the scientific community, worldwide. Its important contribution, starting from the design and extended to the development, clinical trials, scientific support, education of other scientists (surgeons, cardiologists, technicians etc.), and even to sales, makes biomedical engineers a valuable player in the scientific arena. Notably, the sector of implantable devices is constantly raising, as emerging technologies continuously set up new targets.

40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid...

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.

Surgical treatment of tricuspid valve insufficiency promotes early reverse remodeling in patients with axial-flow left ventricular assist devices.

PubMed

Maltais, Simon; Topilsky, Yan; Tchantchaleishvili, Vakhtang; McKellar, Stephen H; Durham, Lucian A; Joyce, Lyle D; Daly, Richard C; Park, Soon J

2012-06-01

The HeartMate II (Thoratec Corp, Pleasanton, Calif) continuous-flow left ventricular assist device has emerged as the standard of care for patients with advanced heart failure. The objective of this study was to assess the safety and early effectiveness of concomitant tricuspid valve procedures in patients undergoing implantation of a HeartMate II device. From February 2007 to April 2010, 83 patients underwent HeartMate II left ventricular assist device implantation. Of these, 37 patients had concomitant tricuspid valve procedures (32 repairs, 5 replacements) for severe tricuspid regurgitation. The effects of a tricuspid valve procedure on tricuspid regurgitation and right ventricular remodeling were assessed comparing echocardiographic findings at baseline and 30 days after left ventricular assist device implantation. Overall survival was also compared. Patients undergoing a concomitant tricuspid valve procedure had more tricuspid regurgitation (vena contracta, 5.6 ± 2.1 mm vs 2.9 ± 2.0 mm; P < .001), worse right ventricular dysfunction (right ventricular end-diastolic area, 33.6 ± 6.2 mm vs 31.6 ± 8.5 mm; P = .05), higher mean right atrial pressure (17.4 ± 7.1 mm Hg vs 14.9 ± 5.1 mm Hg; P = .03), and a higher Kormos score (2.6 ± 2.1 vs 1.2 ± 1.4; P = .0008) preoperatively. One month after surgery, tricuspid regurgitation was worse in patients who underwent left ventricular assist device implantation alone (+18.6%), whereas it improved significantly in patients undergoing a concomitant tricuspid valve procedure (-50.2%) (P = .005). A corresponding significant reduction in right ventricular end-diastolic area (33.6% ± 6.2% vs 30.1% ± 9.7%; P = .03) and a trend toward better right ventricular function (55.5% ± 79.7% vs 35.7% ± 60.5%; P = .28) were noted in patients undergoing a concomitant tricuspid valve procedure. Survival was comparable between the 2 groups. In patients with severe tricuspid regurgitation undergoing left ventricular assist device

Surgical revision after percutaneous mitral valve repair by edge-to-edge device: when the strategy fails in the highest risk surgical population.

PubMed

Alozie, Anthony; Westphal, Bernd; Kische, Stephan; Kaminski, Alexander; Paranskaya, Liliya; Bozdag-Turan, Ilkay; Ortak, Jasmin; Schubert, Jochen; Steinhoff, Gustav; Ince, Hüseyin

2014-07-01

Percutaneous edge-to-edge devices for non-surgical repair of mitral valve regurgitation are under clinical evaluation in high-risk patients deemed not suitable for conventional surgery. To address guidelines for initial therapy decision, we here report on 13 cases of surgery after failed percutaneous edge-to-edge mitral valve repair or attempted repair, and discuss methodology and prognostic factors for operative outcome in this high-risk situation. Thirteen patients referred to our cardiothoracic unit after failed percutaneous mitral valve repair or attempted repair using the edge-to-edge technique, were treated surgically for mitral valve failure between June 2010 and December 2012. Pathology of mitral valve before and after interventional mitral valve repair (especially prevalent mode of failure) was evaluated and classified for each individual patient by echocardiography and intraoperative direct visualization. Number of implanted edge-to-edge devices were identified. Preoperative risk scores were matched with intraoperative observations and histopathological findings of valve tissue. Postoperative morbidity and mortality were analysed with respect to mitral valve and patient-related data. Three of 10 patients were referred with severe mitral valve regurgitation/stenosis after initially successful percutaneous edge-to-edge therapy or attempted therapy. In 3 patients, ≥ 2 edge-to-edge devices were implanted leading to very tight edge-to-edge leaflet connection and fibrosis. All patients underwent successful surgical mitral valve replacement and concomitant complete cardiac surgery (CABG, aortic or tricuspid valve surgery, ASD closure and pulmonary vein isolation for atrial fibrillation). The likelihood of repair was reduced with respect to multiple edge-to-edge technology. One device could not be harvested surgically because of embolization. One patient died on the second postoperative day due to sepsis with multiple organ failure. The remaining 12 patients

Minimally Invasive Implantation of HeartWare Assist Device and Simultaneous Tricuspid Valve Reconstruction Through Partial Upper Sternotomy.

PubMed

Hillebrand, Julia; Hoffmeier, Andreas; Djie Tiong Tjan, Tonny; Sindermann, Juergen R; Schmidt, Christoph; Martens, Sven; Scherer, Mirela

2017-05-01

Left ventricular assist device (LVAD) implantation is a well-established therapy to support patients with end-stage heart failure. However, the operative procedure is associated with severe trauma. Third generation LVADs like the HeartWare assist device (HeartWare, Inc., Framingham, MA, USA) are characterized by enhanced technology despite smaller size. These devices offer new minimally invasive surgical options. Tricuspid regurgitation requiring valve repair is frequent in patients with the need for mechanical circulatory support as it is strongly associated with ischemic and nonischemic cardiomyopathy. We report on HeartWare LVAD implantation and simultaneous tricuspid valve reconstruction through minimally invasive access by partial upper sternotomy to the fifth left intercostal space. Four male patients (mean age 51.72 ± 11.95 years) suffering from chronic heart failure due to dilative (three patients) and ischemic (one patient) cardiomyopathy and also exhibiting concomitant tricuspid valve insufficiency due to annular dilation underwent VAD implantation and tricuspid valve annuloplasty. Extracorporeal circulation was established via the ascending aorta, superior vena cava, and right atrium. In all four cases the LVAD implantation and tricuspid valve repair via partial median sternotomy was successful. During the operative procedure, no conversion to full sternotomy was necessary. One patient needed postoperative re-exploration because of pericardial effusion. No postoperative focal neurologic injury was observed. New generation VADs are advantageous because of the possibility of minimally invasive implantation procedure which can therefore minimize surgical trauma. Concomitant tricuspid valve reconstruction can also be performed simultaneously through partial upper sternotomy. Nevertheless, minimally invasive LVAD implantation is a challenging operative technique. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals

21 CFR 870.3925 - Replacement heart valve.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Replacement heart valve. 870.3925 Section 870.3925...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any...

21 CFR 870.3925 - Replacement heart valve.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Replacement heart valve. 870.3925 Section 870.3925...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any...

21 CFR 870.3925 - Replacement heart valve.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Replacement heart valve. 870.3925 Section 870.3925...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any...

21 CFR 870.3925 - Replacement heart valve.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Replacement heart valve. 870.3925 Section 870.3925...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any...

21 CFR 870.3925 - Replacement heart valve.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Replacement heart valve. 870.3925 Section 870.3925...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3925 Replacement heart valve. (a) Identification. A replacement heart valve is a device intended to perform the function of any...

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.

A programmable point-of-care device for external CSF drainage and monitoring.

PubMed

Simkins, Jeffrey R; Subbian, Vignesh; Beyette, Fred R

2014-01-01

This paper presents a prototype of a programmable cerebrospinal fluid (CSF) external drainage system that can accurately measure the dispensed fluid volume. It is based on using a miniature spectrophotometer to collect color data to inform drain rate and pressure monitoring. The prototype was machined with 1 μm dimensional accuracy. The current device can reliably monitor the total accumulated fluid volume, the drain rate, the programmed pressure, and the pressure read from the sensor. Device requirements, fabrication processes, and preliminary results with an experimental set-up are also presented.

Magnetostrictive valve

NASA Technical Reports Server (NTRS)

Casabianca, C. C.

1978-01-01

Device requires no moving parts and has less stringent tolerances. Device uses magnetostrictive powdered metal and electromagnets, rather than solenoid. Device is more reliable than conventional valves.

Safety and efficacy of a low-cost glaucoma drainage device for refractory childhood glaucoma.

PubMed

Kaushik, Sushmita; Kataria, Pankaj; Raj, Srishti; Pandav, Surinder Singh; Ram, Jagat

2017-12-01

To evaluate the safety and efficacy of a low-cost glaucoma drainage device (GDD), Aurolab aqueous drainage implant (AADI), similar in design to the Baerveldt glaucoma implant (BGI), in refractory childhood glaucoma. This prospective interventional study was conducted in a tertiary care postgraduate teaching institute. Children aged <16 years with uncontrolled intraocular pressure (IOP) refractory to medical treatment and considered at high risk of failure following trabeculectomy were recruited. Eligible children were implanted with the AADI. Those completing minimum 6-month follow-up were included. Main outcome measures were IOP reduction from preoperative values and postoperative complications. 34 eyes of 31 patients were analysed. Average follow-up was 18.3±6.9 months. Mean IOP reduced from 27.4±7.5 mm Hg on maximum medication to 14.6±10.74 mm Hg, 13.8±7.5 mm Hg, 12.8±5.6 mm Hg and 14.7±5.8 mm Hg at 1 week, 6 months, 1 year (32 eyes of 29 children) and 2 years (25 eyes of 22 children) postoperatively, respectively (p<0.001). The cumulative probability of success was 91.18% at 6 months and 81.7% at 18-24 months. Mean number of topical medications decreased from 3.1±0.6 to 1.8±1.3 at 6 months and 1.6±1.1 at 24 months (p<0.001). Preoperatively, 25 patients required systemic acetazolamide, decreasing to three patients at 2 years. There was no tube erosion or infection. One eye developed retinal detachment. The AADI appears to be a viable low-cost GDD with effectiveness and safety profile comparable with published reports of the BGI and Ahmed glaucoma valve implant in children. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

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 aortic valve replacement with new-generation devices: A systematic review and meta-analysis.

PubMed

Barbanti, Marco; Buccheri, Sergio; Rodés-Cabau, Josep; Gulino, Simona; Généreux, Philippe; Pilato, Gerlando; Dvir, Danny; Picci, Andrea; Costa, Giuliano; Tamburino, Corrado; Leon, Martin B; Webb, John G

2017-10-15

The aim of this study was to conduct a weighted meta-analysis to determine the rates of acute (≤30days) major outcomes after (TAVR) with second-generation devices. A comprehensive search of multiple electronic databases from January 2011 to May 2017 was conducted using predefined criteria. New-generation TAVR devices were defined as any device which received CE mark approval or is still under evaluation for CE marking after CoreValve and SAPIEN XT prostheses. A total of 37 studies including 10,822 patients met inclusion criteria and were included in the analysis. Devices investigated in the studies were the following: SAPIEN 3 (n=5423, 45.9%), Lotus Valve (n=3007, %), Portico (n=130, 1.1%), JenaValve (n=345, 2.9%), Symetis Acurate (n=1314, 11,1%), and Evolut R (n=1603, 13.6%). Thirty-day all-cause and cardiovascular 30-day death were 2.2% (95% CI: 1.6% to 2.8%) and 1.6% (95% CI: 0.9% to 2.3%), respectively; Any stroke and major/disabling stroke occurred at a pooled estimate rate of 2.6% (95% CI: 2.0% to 3.3%) and 0.9% (95% CI: 0.2% to 1.6%), respectively; life-threatening bleeding, 3.9% (95% CI: 2.9% to 5.0%); major vascular complications, 4.5% (95% CI: 3.7% to 5.4%); pacemaker implantation, 16.2% (95% CI: 12.7% to 19.6%); more than mild aortic regurgitation, 1.6% (95% CI: 0.9 to 2.3). Second-generation TAVR devices are associated with very low mortality and major complications rates at 30-day, and improved prosthesis performance with <2% of patients having more than mild post-procedural aortic regurgitation. On the other hand, the need for pacemaker implantation seems to remain an unresolved issue, and warrants further investigation. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a micro-mechanical valve in a novel glaucoma implant.

PubMed

Siewert, Stefan; Schultze, Christine; Schmidt, Wolfram; Hinze, Ulf; Chichkov, Boris; Wree, Andreas; Sternberg, Katrin; Allemann, Reto; Guthoff, Rudolf; Schmitz, Klaus-Peter

2012-10-01

This paper describes methods for design, manufacturing and characterization of a micro-mechanical valve for a novel glaucoma implant. The implant is designed to drain aqueous humour from the anterior chamber of the eye into the suprachoroidal space in case of an elevated intraocular pressure (IOP). In contrast to any existing glaucoma drainage device (GDD), the valve mechanism is located in the anterior chamber and there, surrounded by aqueous humour, immune to fibrosis induced failure. For the prevention of hypotony the micro-mechanical valve is designed to open if the physiological pressure difference between the anterior chamber and the suprachoroidal space in the range of 0.8 mmHg to 3.7 mmHg is exceeded. In particular the work includes: (i) manufacturing and morphological characterization of polymer tubing, (ii) mechanical material testing as basis for (iii) the design of micro-mechanical valves using finite element analysis (FEA), (iv) manufacturing of microstent prototypes including micro-mechanical valves by femtosecond laser micromachining and (v) the experimental fluid-mechanical characterization of the manufactured microstent prototypes with regard to valve opening pressure. The considered materials polyurethane (PUR) and silicone (SIL) exhibit low elastic modulus and high extensibility. The unique valve design enables a low opening pressure of micro-mechanical valves. An ideal valve design for PUR and SIL with an experimentally determined opening pressure of 2 mmHg and 3.7 mmHg is identified. The presented valve approach is suitable for the inhibition of hypotony as a major limitation of today's GDD and will potentially improve the minimally invasive treatment of glaucoma.

Randomised clinical trial of chest drainage systems.

PubMed Central

Graham, A N; Cosgrove, A P; Gibbons, J R; McGuigan, J A

1992-01-01

BACKGROUND: Problems in the management of thoracic trauma have stimulated the search for an alternative to underwater seals for drainage of the pleural cavity. A chest drainage bag incorporating a one way flutter valve has been compared with underwater seal drains in a randomised clinical trial. METHODS: During June-December 1989 119 patients undergoing elective thoracotomy were randomised to receive postoperative chest drainage by drainage bags (56 patients, 87 drains) or by underwater seal drains (63 patients, 98 drains). Daily drainage volumes, the requirement for pleural suction, mobility, and complications were recorded prospectively. RESULTS: There was no significant difference between the two groups in the mean volume drained, the requirements for pleural suction, or the occurrence of complications. Patients with drainage bags were fully mobile 23 hours (95% confidence interval 0-47 hours) earlier than the others. CONCLUSIONS: When used after elective thoracotomy drainage bags are safe and effective and permit earlier mobility than underwater seal drains. PMID:1496507

Cerebrospinal fluid drainage for syringomyelia.

PubMed

Williams, B; Sgouros, S; Nenji, E

1995-12-01

Twenty-eight years of experience with syringomyelia of various causes in the syringomyelia clinic at the Midland Centre for Neurosurgery and Neurology has provided a database of 723 patients, mostly adults, with either hindbrain herniation, syringomyelia or both. Treatment of syringomyelia by drainage has never been the optimum primary treatment on the basis that the cavity is usually secondary to some other disturbance of the cerebrospinal fluid pathways. Over this period 73 patients had either syrinx drainage (56 syringopleural, 14 syringo-subarachnoid shunts) or other procedure such as myelotomy and cord transection. Ten years after operation only 53.5% and 50% of these two groups respectively continued to remain clinically stable. A complication rate of 15.7% included fatal haemorrhage, infection and displacement of drains. At second operation or necropsy at least 5% of shunts were found to be blocked. All the shunts were inserted without a valve and the lowering of the intrasyrinx pressure has therefore been energetic when the lower end of the drainage tube has been taken to the pleural or peritoneal cavities. This produced collapse of the cord cavities around the tip of the drainage tube and increased the likelihood of blockage. If the mechanisms which were responsible for the syringomyelia were still operative then recurrence was likely to occur alongside the drainage tube leaving the tube immured in the wall of the syrinx cavity. When hydrocephalus was present, in addition treatment of the hydrocephalus by a valved shunt to the peritoneum or to the right atrium was often effective in improving the syringomyelia. This treatment has also been used in patients without hydrocephalus. The mechanisms of improvement were unclear but this treatment stratagem has nevertheless been employed in 45 cases. In 30 out of these 45 cases the drainage of cerebrospinal fluid from outside the syrinx cavities seemed to be worthwhile; 10 patients suffered some form of

The liquid crystal light valve, an optical-to-optical interface device

NASA Technical Reports Server (NTRS)

Jacobson, A. D.; Beard, T. D.; Bleha, W. P.; Margerum, J. D.; Wong, S. Y.

1972-01-01

A photoactivated liquid crystal light valve is described as an optical-to-optical interface device (OTTO) which is designed to transfer an optical image from a noncoherent light beam to a spatially coherent beam of light, in real time. Schematics of OTTO in use, the liquid cyrstal cell, and the liquid crystal structure are presented. Sensitivity characteristics and the principles of operation are discussed.

Comparison of Six Different Silicones In Vitro for Application as Glaucoma Drainage Device

PubMed Central

Windhövel, Claudia; Harder, Lisa; Bach, Jan-Peter; Teske, Michael; Grabow, Niels; Eickner, Thomas; Chichkov, Boris; Nolte, Ingo

2018-01-01

Silicones are widely used in medical applications. In ophthalmology, glaucoma drainage devices are utilized if conservative therapies are not applicable or have failed. Long-term success of these devices is limited by failure to control intraocular pressure due to fibrous encapsulation. Therefore, different medical approved silicones were tested in vitro for cell adhesion, cell proliferation and viability of human Sclera (hSF) and human Tenon fibroblasts (hTF). The silicones were analysed also depending on the sample preparation according to the manufacturer’s instructions. The surface quality was characterized with environmental scanning electron microscope (ESEM) and water contact angle measurements. All silicones showed homogeneous smooth and hydrophobic surfaces. Cell adhesion was significantly reduced on all silicones compared to the negative control. Proliferation index and cell viability were not influenced much. For development of a new glaucoma drainage device, the silicones Silbione LSR 4330 and Silbione LSR 4350, in this study, with low cell counts for hTF and low proliferation indices for hSF, and silicone Silastic MDX4-4210, with low cell counts for hSF and low proliferation indices for hTF, have shown the best results in vitro. Due to the high cell adhesion shown on Silicone LSR 40, 40,026, this material is unsuitable. PMID:29495462

Assessment of a new silicone tri-leaflet valve seamlessly assembled with blood chamber for a low-cost ventricular assist device.

PubMed

Hirai, S; Fukunaga, S; Sueshiro, M; Watari, M; Sueda, T; Matsuura, Y

1998-06-01

We have developed a practical, low-cost ventricular assist device (VAD) comprising a newly designed blood chamber with a silicone lenticular sac and two silicone tri-leaflet valves (STV), made en bloc. This new VAD is seamless, can be made cost-effectively and assembled with the blood chamber and valve as one body. This novel design should reduce the incident of thrombus formation because of the absence of a junction at the connecting ring and because of the use of flexible silicone materials which have both antithrombogenecity and biocompatibility. In in vitro hemodynamics testing, a batch of 3 consecutively manufactured VADs with STVs underwent hydrodynamic functional testing. These showed less regurgitation, a lower value of water hammer phenomenon, and a slightly greater pressure gradient across the valves than a mechanical valve (MV) [Björk-Shiley monostrut valve]. The flow and pulsatile efficiency were adequate and similar to that of a VAD with MVs. In in vitro durability and hemolysis tests, a VAD with STV functioned well for 54 days and showed similar hemolytic profiles to a VAD with MVs. In an in vivo acute experiment using an adult sheep, our device was problem-free providing sufficient output as a left ventricular assist device (LVAD). Although it will be necessary to decrease the pressure gradient across this STV in the future, our device showed efficient performance as a practical land cost-effective VAD for short term use.

Glaucoma in modified osteo-odonto-keratoprosthesis eyes: role of additional stage 1A and Ahmed glaucoma drainage device-technique and timing.

PubMed

Iyer, Geetha; Srinivasan, Bhaskar; Agarwal, Shweta; Shetty, Roshni; Krishnamoorthy, Sripriya; Balekudaru, Shantha; Vijaya, Lingam

2015-03-01

To report the technique, timing, and outcomes of the Ahmed glaucoma drainage device in eyes with the modified osteo-odonto-keratoprosthesis (MOOKP) and the role of an additional stage 1A to the Rome-Vienna protocol. Retrospective interventional case series. Case records of 22 eyes of 20 patients with high intraocular pressure at various stages of the MOOKP procedure performed in 85 eyes of 82 patients were studied. Stage 1A, which includes total iridodialysis, intracapsular cataract extraction, and anterior vitrectomy, was done in all eyes as the primary stage. Seventeen Ahmed glaucoma drainage devices were implanted in 15 eyes of 14 patients (chemical injury in 9 [10 eyes] and Stevens-Johnson syndrome in 5 patients). Implantation was performed during and after stage 1A in 2 and 7 eyes, respectively, after stage 1B+1C in 1 eye, and after stage 2 in 6 eyes. Eleven of 15 eyes (73.3%) remained stable with adequate control of intraocular pressure over a mean follow-up period of 33.68 months (1-90 months). Complications related to the drainage device were hypotony in 1 eye and vitreous block of the tube in 1 eye. It is ideal to place the Ahmed glaucoma drainage device prior to the mucosal graft when the anatomy of the ocular surface is least altered with best outcomes. The technique of placement of the drainage device during the various stages of the MOOKP procedure has been described. The intraocular pressure stabilized in three quarters of the eyes with pre-existing glaucoma. Copyright © 2015 Elsevier Inc. All rights reserved.

Implantation of a second glaucoma drainage device.

PubMed

Francis, Brian A; Fernandes, Rodrigo A B; Akil, Handan; Chopra, Vikas; Diniz, Bruno; Tan, James; Huang, Alex

2017-05-01

To evaluate success rates in controlling intraocular pressure (IOP) after implantation of a second glaucoma drainage device (GDD) with a Baerveldt glaucoma implant in patients with refractory glaucoma, with a secondary aim of reducing the need for postoperative glaucoma medications. This retrospective, noncomparative, interventional study included patients undergoing a second GDD for uncontrolled glaucoma from a tertiary care glaucoma service. Data were obtained from the medical records for the preoperative period and after the 1st, 15th, and 30th day, 3, 6, and 12 months, and then yearly until the last postoperative visit. Visual acuity, IOP, and number of glaucoma medications (NGM) from the follow-up visits were compared to baseline. Success and failure criteria were analyzed based on IOP level or need of glaucoma medications. Forty-nine patients were studied, with a mean follow-up time of 25 ± 21 months. The mean preoperative IOP was 23.7 ± 8.2 mmHg, and decreased to 14.8 ± 4.0 mmHg after 1 year, 14.4 ± 3.9 mmHg after 2 years, and 16.6 ± 8.5 mmHg after 3 years. The mean preoperative NGM was 3.4 ± 1.3, and decreased to 2.0 ± 1.8 after 1 year, 2.5 ± 1.6 after 2 years, and 2.8 ± 2.0 after 3 years. Absolute success was 9% after 1 year for a postoperative IOP between 5 and 18 mmHg, and 76% for a postoperative IOP between 5 and 21 mmHg. The qualified success was 88% at the first and second years and 83% at the third year. With up to 3 years of follow-up, a second glaucoma drainage device was successful in reducing IOP to below 21 mmHg, but not as successful below 18 mmHg. The success rate is improved with the use of glaucoma medications with up to 3 years of follow-up.

21 CFR 870.3945 - Prosthetic heart valve sizer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of the...

21 CFR 870.3945 - Prosthetic heart valve sizer.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of the...

21 CFR 870.3945 - Prosthetic heart valve sizer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of the...

21 CFR 870.3945 - Prosthetic heart valve sizer.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of the...

21 CFR 870.3945 - Prosthetic heart valve sizer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Prosthetic heart valve sizer. 870.3945 Section 870...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3945 Prosthetic heart valve sizer. (a) Identification. A prosthetic heart valve sizer is a device used to measure the size of the...

Polymeric heart valves for surgical implantation, catheter-based technologies and heart assist devices.

PubMed

Bezuidenhout, Deon; Williams, David F; Zilla, Peter

2015-01-01

Efficient function and long-term durability without the need for anticoagulation, coupled with the ability to be accommodated in many different types of patient, are the principal requirements of replacement heart valves. Although the clinical use of valves appeared to have remained steady for several decades, the evolving demands for the elderly and frail patients typically encountered in the developed world, and the needs of much younger and poorer rheumatic heart disease patients in the developing world have now necessitated new paradigms for heart valve technologies and associated materials. This includes further consideration of durable elastomeric materials. The use of polymers to produce flexible leaflet valves that have the benefits of current commercial bioprosthetic and mechanical valves without any of their deficiencies has been held desirable since the mid 1950s. Much attention has been focused on thermoplastic polyurethanes in view of their generally good physico-chemical properties and versatility in processing, coupled with the improving biocompatibility and stability of recent formulations. Accelerated in vitro durability of between 600 and 1000 million cycles has been achieved using polycarbonate urethanes, and good resistance to degradation, calcification and thrombosis in vivo has been shown with some polysiloxane-based polyurethanes. Nevertheless, polymeric valves have remained relegated to use in temporary ventricular assist devices for bridging heart failure patients to transplantation. Some recent studies suggest that there is a greater degree of instability in thermoplastic materials than hitherto believed so that significant challenges remain in the search for the combination of durability and biocompatibility that would allow polymeric valves to become a clinical reality for surgical implantation. Perhaps more importantly, they could become candidates for use in situations where minimally invasive transcatheter procedures are used to

3D Printed Multimaterial Microfluidic Valve

PubMed Central

Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

2016-01-01

We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

3D Printed Multimaterial Microfluidic Valve.

PubMed

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

2016-01-01

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

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

PubMed

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

2017-02-15

This study aims to evaluate the safety and performance of the new embolic deflection device TriGuard™HDH in patients undergoing TAVR. Transcatheter aortic valve replacement (TAVR) is associated with a high incidence of new cerebral ischemic lesions. The use of an embolic protection device may reduce the frequency of TAVR-related embolic events. This prospective, single arm feasibility pilot study included 14 patients with severe symptomatic aortic stenosis scheduled for TAVR. Cerebral diffusion weighted magnetic resonance imaging (DWI) was planned in all patients one day before and at day 4 (±2) after the procedure. Major adverse cerebral and cardiac events (MACCEs) were recorded for all patients. Primary endpoints of this study were I) device performance success defined as coverage of the aortic arch takeoffs throughout the entire TAVR procedure and II) MACCE occurrence. Secondary endpoints included the number and the volume of new cerebral ischemic lesions on DWI. Thirteen patients underwent transfemoral TAVR and one patient a transapical procedure. Edwards SAPIEN valve prosthesis was implanted in 8 (57%) patients and Medtronic CoreValve prosthesis in the remaining 6 (43%). Predefined performance success of the TriGuard™HDH device was achieved in 9 (64%) patients. The composite endpoint MACCE occurred in none of the patients. Post-procedural DWI was performed in 11 patients. Comparing the DWI of these patients to a historical control group showed no reduction in number [median 5.5 vs. 5.0, P = 0.857], however there was a significant reduction in mean lesion volume per patient [median 13.8 vs. 25.1, P = 0.049]. This study showed the feasibility and safety of using the TriGuard™HDH for cerebral protection during TAVR. This device did not decrease the number of post-procedural new cerebral DWI lesions, however its use showed decreased lesion volume as compared to unprotected TAVR. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Contamination avoidance devices for poppettype shutoff valves

NASA Technical Reports Server (NTRS)

Endicott, D. L.

1973-01-01

The determination of the cycle life is reported of the scal closure of a typical poppet-type shutoff valve in an uncontaminated GH2 environment and then compared this component performance with simulated operation with GN2 and LN2 containing controlled amounts of AL2O3 contaminant particles. The original valve design was tested for contamination damage tolerance characteristics under full-flow and cyclic-operating conditions, redesigned to improve the damage tolerance to contaminants, and then retested. The redesigned valve was found to have acceptable tolerance characteristics under all full-flow conditions and cyclic operation with small (25-75 microns) particulate contamination. The tolerance characteristics of the valve under cyclic conditions with large (75-250 microns) particulate contamination was improved but was not found to be completely satisfactory.

The Results of the Use of Ahmed Valve in Refractory Glaucoma Surgery

PubMed Central

Bikbov, Mukharram Mukhtaramovich

2015-01-01

ABSTRACT The treatment of refractory glaucoma (RG) is challenging. The commonly adopted strategy in RG treatment is a glaucoma drainage device (GDD) implantation, which despite its radical nature may not always provide the desired intraocular pressure (IOP) levels for a long term. This review is based on the scientific literature on Ahmed glaucoma valve (AGV) implantation for refractory glaucoma. The technique of AGV implantation is described and data for both the types, FP7 and FP8 performance are presented. The outcome with adjunct antimetabolite and anti-VEGF drugs are also highlighted. An insight is given about experimental and histological examinations of the filtering bleb encapsulation. The article also describes various complications and measures to prevent them. How to cite this article: Bikbov MM, Khusnitdinov II. The Results of the Use of Ahmed Valve in Refractory Glaucoma Surgery. J Curr Glaucoma Pract 2015;9(3):86-91. PMID:26997843

21 CFR 870.3935 - Prosthetic heart valve holder.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device is...

21 CFR 870.3935 - Prosthetic heart valve holder.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device is...

21 CFR 870.3935 - Prosthetic heart valve holder.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device is...

21 CFR 870.3935 - Prosthetic heart valve holder.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device is...

21 CFR 870.3935 - Prosthetic heart valve holder.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Prosthetic heart valve holder. 870.3935 Section... heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a replacement heart valve while it is being sutured into place. (b) Classification. Class I. The device is...

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2014 CFR

2014-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief devices in light liquid...

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2011 CFR

2011-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief devices in light liquid...

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2012 CFR

2012-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief devices in light liquid...

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2013 CFR

2013-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief devices in light liquid...

Integration of continuous-flow sampling with microchip electrophoresis using poly(dimethylsiloxane)-based valves in a reversibly sealed device.

PubMed

Li, Michelle W; Martin, R Scott

2007-07-01

Here we describe a reversibly sealed microchip device that incorporates poly(dimethylsiloxane) (PDMS)-based valves for the rapid injection of analytes from a continuously flowing stream into a channel network for analysis with microchip electrophoresis. The microchip was reversibly sealed to a PDMS-coated glass substrate and microbore tubing was used for the introduction of gas and fluids to the microchip device. Two pneumatic valves were incorporated into the design and actuated on the order of hundreds of milliseconds, allowing analyte from a continuously flowing sampling stream to be injected into an electrophoresis separation channel. The device was characterized in terms of the valve actuation time and pushback voltage. It was also found that the addition of sodium dodecyl sulfate (SDS) to the buffer system greatly increased the reproducibility of the injection scheme and enabled the analysis of amino acids derivatized with naphthalene-2,3-dicarboxaldehyde/cyanide. Results from continuous injections of a 0.39 nL fluorescein plug into the optimized system showed that the injection process was reproducible (RSD of 0.7%, n = 10). Studies also showed that the device was capable of monitoring off-chip changes in concentration with a device lag time of 90 s. Finally, the ability of the device to rapidly monitor on-chip concentration changes was demonstrated by continually sampling from an analyte plug that was derivatized upstream from the electrophoresis/continuous flow interface. A reversibly sealed device of this type will be useful for the continuous monitoring and analysis of processes that occur either off-chip (such as microdialysis sampling) or on-chip from other integrated functions.

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.

Programmable shunt valves for the treatment of hydrocephalus: a systematic review.

PubMed

Xu, H; Wang, Z X; Liu, F; Tan, G W; Zhu, H W; Chen, D H

2013-09-01

To evaluate the clinical effectiveness of programmable valves compared with non-programmable valves of hydrocephalus. In this paper, the authors report a systematic review and meta-analysis of complications and revision rate for programmable valves and non-programmable implantation. Randomized or non-randomized controlled trials of hydrocephalus treated by programmable and non-programmable valves were considered for inclusion. Seven published reports of eligible studies involving 1702 participants meet the inclusion criteria. Compared with non-programmable, programmable valves had no significant difference in catheter-related complications [RR = 0.88, 95%CI (0.66,1.19), p = 0.10] and infection rate [RR = 1.25, 95%CI (0.92,1.69), p = 1.00]. There were significant differences in overall complications [RR = 0.80, 95%CI (0.67,0.96), p < 0.01], over-drainage or under-drainage complications [RR = 0.44, 95%CI (0.31,0.63), p < 0.01] and revision rate [RR = 0.56, 95%CI (0.45,0.69), p < 0.01] in favor of programmable valves. Although the studies seem to demonstrate a small advantage for the programmable shunts, the probable bias and the difficulties in patient selection are too important to make a general conclusion. Copyright © 2013. Published by Elsevier Ltd.

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.

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

Overdrainage and shunt technology. A critical comparison of programmable, hydrostatic and variable-resistance valves and flow-reducing devices.

PubMed

Aschoff, A; Kremer, P; Benesch, C; Fruh, K; Klank, A; Kunze, S

1995-04-01

When vertical body position is simulated, conventional differential pressure valves show an absolutely unphysiological flow, which is 2-170 times the normal liquor production rate. Although this is compensated in part by the resistance of the silicon tubes, which may produce up to 94% of the resistance of the complete shunt system, a negative intracranial pressure (ICP) of up to 30-44 cmH2O is an unavoidable consequence, which can be followed by subdural hematomas, slit ventricles, and other well-known complications. Modern shunt technology offers programmable, hydrostatic, and "flow-controlled" valves and anti-siphon devices; we have tested 13 different designs from 7 manufacturers (56 specimens), using the "Heidelberg Valve Test Inventory" with 16 subtests. "Programmable" valves reduce, but cannot exclude, unphysiological flow rates: even in the highest position and in combination with a standard catheter typical programmable Medos-Hakim valves allow a flow of 93-232 ml/h, Sophy SU-8-valves 86-168 ml/h with 30 cmH2O. The effect of hydrostatic valves (Hakim-Lumbar, Chhabra) can be inactivated by movements of daily life. The weight of the metal balls in most valves was too low for adequate flow reduction. Antisiphon devices are highly dependent on external, i.e. subcutaneous, pressure which has unpredictable influences on shunt function, and clinically is sometimes followed by shunt insufficiency. Two new Orbis-Sigma valves showed relatively physiological flow rates even when the vertical position (30 cmH2O) was simulated. One showed an insufficient flow (5.7 ml/h), and one was primarily obstructed. These have by far the smallest outlet of all valves. Additionally, the ruby pin tends to stick. Therefore, a high susceptibility to obliterations and blockade is unavoidable. Encouraging results obtained in pediatric patients contrast with disappointing experiences in some German and Swedish hospitals, which suggests that our laboratory findings are confirmed by

[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.

Hydrodynamic endurance test of the prosthetic valve used in the various types of the ventricular assist device.

PubMed

Nitta, S; Yambe, T; Katahira, Y; Sonobe, T; Saijoh, Y; Naganuma, S; Akiho, H; Kakinuma, Y; Tanaka, M; Miura, M

1991-12-01

To evaluate the various basic designs of the pump chambers used in the ventricular assist devices (VADs), hydrodynamic endurance test was performed from the viewpoint of the durability of the prosthetic valves used in the VAD. For the hydrodynamic analysis, we designed three basic types of pump (sac type, diaphragm type, and pusher plate type) using the same material and having the same capacity and shape. Prosthetic valves in these VADs were tested from the standpoint of the water hammer effect, which affects the valve durability, to determine which pump design would be most durable as a prosthetic valve in the VAD. The water-hammer phenomenon was evaluated using the maximum pressure gradient (MPG) across the prosthetic valve in the moc circulatory loop. Maximum pump output was recorded when we used the diaphragm type model, and minimum MPG in the commonly used driving condition of the VAD were recorded when we used the sac type model. The results suggest that the sac type VAD model is the most durable design for the prosthetic value.

40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

Code of Federal Regulations, 2012 CFR

2012-07-01

... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light liquid...

40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

Code of Federal Regulations, 2013 CFR

2013-07-01

... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light liquid...

40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

Code of Federal Regulations, 2011 CFR

2011-07-01

... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light liquid...

40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

Code of Federal Regulations, 2014 CFR

2014-07-01

... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light liquid...

40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

Code of Federal Regulations, 2010 CFR

2010-07-01

... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light liquid...

The value of programmable shunt valves for the management of subdural collections in patients with hydrocephalus.

PubMed

Pachatouridis, Dimitrios; Alexiou, George A; Mihos, Evaggelos; Fotakopoulos, George; Voulgaris, Spyridon

2013-01-01

The aim of the present study was to assess the value of electromagnetic programmable shunt valves for the treatment of subdural collections. Adult patients with hydrocephalus of various causes that were treated with programmable shunt valves during the last ten years were retrospectively studied. In 127 patients, 139 electromagnetic programmable shunt valves were implanted. A nontraumatic subdural fluid collection was detected in 12 patients. The treatment of these patients consisted of reprogramming of the valve's opening pressure. In 5 patients small subdural hematomas were detected; 4 of these patients were treated by raising the opening pressure alone and one patient required surgical drainage and change of the pressure setting. Traumatic chronic subdural hematomas were detected in 6 patients. These patients were treated by surgical drainage and readjustment of the valve's opening pressure. The ability to treat a shunt-related complication, such as a subdural fluid collection, by reprogramming the valve's opening pressure to a higher setting is an advantage over nonprogrammable valves, and it enables the opening pressure to be slowly lowered once the fluid collection is reabsorbed. Based on our results, we believe that programmable shunt valves should be preferred.

The Value of Programmable Shunt Valves for the Management of Subdural Collections in Patients with Hydrocephalus

PubMed Central

Alexiou, George A.; Mihos, Evaggelos; Fotakopoulos, George; Voulgaris, Spyridon

2013-01-01

Background. The aim of the present study was to assess the value of electromagnetic programmable shunt valves for the treatment of subdural collections. Methods. Adult patients with hydrocephalus of various causes that were treated with programmable shunt valves during the last ten years were retrospectively studied. In 127 patients, 139 electromagnetic programmable shunt valves were implanted. Results. A nontraumatic subdural fluid collection was detected in 12 patients. The treatment of these patients consisted of reprogramming of the valve's opening pressure. In 5 patients small subdural hematomas were detected; 4 of these patients were treated by raising the opening pressure alone and one patient required surgical drainage and change of the pressure setting. Traumatic chronic subdural hematomas were detected in 6 patients. These patients were treated by surgical drainage and readjustment of the valve's opening pressure. Conclusion. The ability to treat a shunt-related complication, such as a subdural fluid collection, by reprogramming the valve's opening pressure to a higher setting is an advantage over nonprogrammable valves, and it enables the opening pressure to be slowly lowered once the fluid collection is reabsorbed. Based on our results, we believe that programmable shunt valves should be preferred. PMID:24453855

Temporal and spatial regulation of epsin abundance and VEGFR3 signaling are required for lymphatic valve formation and function.

PubMed

Liu, Xiaolei; Pasula, Satish; Song, Hoogeun; Tessneer, Kandice L; Dong, Yunzhou; Hahn, Scott; Yago, Tadayuki; Brophy, Megan L; Chang, Baojun; Cai, Xiaofeng; Wu, Hao; McManus, John; Ichise, Hirotake; Georgescu, Constantin; Wren, Jonathan D; Griffin, Courtney; Xia, Lijun; Srinivasan, R Sathish; Chen, Hong

2014-10-14

Lymphatic valves prevent the backflow of the lymph fluid and ensure proper lymphatic drainage throughout the body. Local accumulation of lymphatic fluid in tissues, a condition called lymphedema, is common in individuals with malformed lymphatic valves. The vascular endothelial growth factor receptor 3 (VEGFR3) is required for the development of lymphatic vascular system. The abundance of VEGFR3 in collecting lymphatic trunks is high before valve formation and, except at valve regions, decreases after valve formation. We found that in mesenteric lymphatics, the abundance of epsin 1 and 2, which are ubiquitin-binding adaptor proteins involved in endocytosis, was low at early stages of development. After lymphatic valve formation, the initiation of steady shear flow was associated with an increase in the abundance of epsin 1 and 2 in collecting lymphatic trunks, but not in valve regions. Epsin 1 and 2 bound to VEGFR3 and mediated the internalization and degradation of VEGFR3, resulting in termination of VEGFR3 signaling. Mice with lymphatic endothelial cell-specific deficiency of epsin 1 and 2 had dilated lymphatic capillaries, abnormally high VEGFR3 abundance in collecting lymphatics, immature lymphatic valves, and defective lymph drainage. Deletion of a single Vegfr3 allele or pharmacological suppression of VEGFR3 signaling restored normal lymphatic valve development and lymph drainage in epsin-deficient mice. Our findings establish a critical role for epsins in the temporal and spatial regulation of VEGFR3 abundance and signaling in collecting lymphatic trunks during lymphatic valve formation. Copyright © 2014, American Association for the Advancement of Science.

Temporal and Spatial Regulation of Epsin Abundance and VEGFR3 Signaling are Required for Lymphatic Valve Formation and Function

PubMed Central

Liu, Xiaolei; Pasula, Satish; Song, Hoogeun; Tessneer, Kandice L.; Dong, Yunzhou; Hahn, Scott; Yago, Tadayuki; Brophy, Megan; Chang, Baojun; Cai, Xiaofeng; Wu, Hao; McManus, John; Ichise, Hirotake; Georgescu, Constantin; Wren, Jonathan D.; Griffin, Courtney; Xia, Lijun; Srinivasan, R. Sathish; Chen, Hong

2014-01-01

Lymphatic valves prevent the backflow of the lymph fluid and ensure proper lymphatic drainage throughout the body. Local accumulation of lymphatic fluid in tissues, a condition called lymphedema, is common in individuals with malformed lymphatic valves. The vascular endothelial growth factor receptor 3 (VEGFR3) is required for the development of lymphatic vascular system. The abundance of VEGFR3 in collecting lymphatic trunks is high before valve formation and, except at valve regions, decreases after valve formation. We found that in mesenteric lymphatics, the abundance of epsin 1 and 2, which are ubiquitin-binding adaptor proteins involved in endocytosis, was low at early stages of development. After lymphatic valve formation, the initiation of steady shear flow was associated with an increase in the abundance of epsin 1 and 2 in collecting lymphatic trunks, but not in valve regions. Epsin 1 and 2 bound to VEGFR3 and mediated the internalization and degradation of VEGFR3, resulting in termination of VEGFR3 signaling. Mice with lymphatic endothelial cell-specific deficiency of epsin 1 and 2 had dilated lymphatic capillaries, abnormally high VEGFR3 abundance in collecting lymphatics, immature lymphatic valves, and defective lymph drainage. Deletion of a single Vegfr3 allele or pharmacological suppression of VEGFR3 signaling restored normal lymphatic valve development and lymph drainage in epsin-deficient mice. Our findings establish a critical role for epsins in the temporal and spatial regulation of VEGFR3 abundance and signaling in collecting lymphatic trunks during lymphatic valve formation. PMID:25314967

Transcatheter valve underexpansion limits leaflet durability: implications for valve-in-valve procedures

PubMed Central

Martin, Caitlin; Sun, Wei

2016-01-01

Transcatheter aortic valve (TAV) implantation within a failed bioprosthetic valve is a growing trend for high-risk patients. The non-compliant stent of the previous prosthesis may prevent full expansion of the TAV, which has been shown to distort the leaflet configuration, and has been hypothesized to adversely affect durability. In this study, TAV leaflet fatigue damage under cyclic pressurization in the setting of stent underexpansion by 0 (fully expanded), 1, 2 and 3 mm was simulated using finite element analysis to test this hypothesis. In the 2 and 3 mm underexpanded devices, the TAV leaflets exhibited severe pin-wheeling during valve closure, which increased leaflet stresses dramatically, and resulted in accelerated fatigue damage of the leaflets. The leaflet fatigue damage in the 1 mm underexpanded case was similar to that in the fully expanded case. Clinically a range of 10% to 15% underexpansion is generally considered acceptable; however, it was observed in this study that ≥2 mm (≥9.1%) underexpansion, will significantly impact device durability. Further study is necessary to determine the impact of various deployment conditions, i.e. non-uniform and non-circular deployments and different implantation heights, on differing TAV devices, but it is clear that the normal TAV leaflet configuration must be preserved in order to preserve durability. PMID:27734178

27. Pump Room interiorDrainage pump motor control center with main ...

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

27. Pump Room interior-Drainage pump motor control center with main valve control panel at right. - Hunters Point Naval Shipyard, Drydock No. 4, East terminus of Palou Avenue, San Francisco, San Francisco County, CA

Performance of current-in-plane pseudo-spin-valve devices on CMOS silicon-on-insulator underlayers

NASA Astrophysics Data System (ADS)

Katti, R. R.; Zou, D.; Reed, D.; Schipper, D.; Hynes, O.; Shaw, G.; Kaakani, H.

2003-05-01

Prior work has shown that current-in-plane (CIP) giant magnetoresistive (GMR) pseudo-spin-valve (PSV) devices grown on bulk Si wafers and bulk complementary metal-oxide semiconductor (CMOS) underlayers exhibit write and read characteristics that are suitable for application as nonvolatile memory devices. In this work, CIP GMR PSV devices fabricated on silicon-on-insulator CMOS underlayers are shown to support write and read performance. Reading and writing fields for selected devices are shown to be approximately 25%-50% that of unselected devices, which provides a margin for reading and writing specific bits in a memory without overwriting bits and without disturbing other bits. The switching characteristics of experimental devices were compared to and found to be similar with Landau-Lifschitz-Gilbert micromagnetic modeling results, which allowed inferring regions of reversible and irreversible rotations in magnetic reversal processes.

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and...

[Novel Device for Creating Multiple Artificial Chordae Loops in Mitral Valve Repair].

PubMed

Shimamura, Yoshiei; Maisawa, Kazuma

2017-08-01

A novel device to create multiple artificial chordae loops for mitral repair is developed. The device consists of a circular metal base with a removable central rod on one end, which can easily be attached or removed by screwing into a hole located on the base, and 51 fixed rods placed radially around the central rod at distances of 10~60 mm from the central rod. A needle with CV-4 e-polytetrafluoroethylene suture is passed through a pledget, and the suture is looped from the central rod around the fixed rod located at the desired loop length. The needle is then passed back through the pledget. The suture is tied over the pledget, bringing it in contact with the central rod. When multiple loops of various lengths are required, different fixed rods located at distances corresponding to the required loop lengths are used. Following creation of the necessary loops, the central rod is unscrewed, and the loops are released from the device. Construction of artificial chordae with this device is quick, reliable, reproducible, and increases the technical possibilities for mitral valve repair.

Sliding pressure control valve for pneumatic hammer drill

DOEpatents

Polsky, Yarom [Albuquerque, NM

2011-08-30

A pneumatic device control apparatus and method comprising a ported valve slidably fitted over a feed tube of the pneumatic device, and using a compliant biasing device to constrain motion of the valve to provide asymmetric timing for extended pressurization of a power chamber and reduced pressurization of a return chamber of the pneumatic device. The pneumatic device can be a pneumatic hammer drill.

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

Recent Advances in Transcatheter Aortic Valve Implantation: Novel Devices and Potential Shortcomings

PubMed Central

Blumenstein, J.; Liebetrau, C.; Linden, A. Van; Moellmann, H.; Walther, T.; Kempfert, J.

2013-01-01

During the past years transcatheter aortic valve implantation (TAVI) has evolved to a standard technique for the treatment of high risk patients suffering from severe aortic stenosis. Worldwide the number of TAVI procedures is increasing exponentially. In this context both the transapical antegrade (TA) and the transfemoral retrograde (TF) approach are predominantly used and can be considered as safe and reproducible access sites for TAVI interventions. As a new technology TAVI is in a constant progress regarding the development of new devices. While in the first years only the Edwards SAPIEN™ and the Medtronic CoreValve™ prostheses were commercial available, recently additional devices obtained CE-mark approval and others have entered initial clinical trials. In addition to enhance the treatment options in general, the main driving factor to further develop new device iterations is to solve the drawbacks of the current TAVI systems: paravalvular leaks, occurrence of AV-blocks and the lack of full repositionability. PMID:24313644

Chest Tube Drainage of the Pleural Space: A Concise Review for Pulmonologists

PubMed Central

2018-01-01

Chest tube insertion is a common procedure usually done for the purpose of draining accumulated air or fluid in the pleural cavity. Small-bore chest tubes (≤14F) are generally recommended as the first-line therapy for spontaneous pneumothorax in non-ventilated patients and pleural effusions in general, with the possible exception of hemothoraces and malignant effusions (for which an immediate pleurodesis is planned). Large-bore chest drains may be useful for very large air leaks, as well as post-ineffective trial with small-bore drains. Chest tube insertion should be guided by imaging, either bedside ultrasonography or, less commonly, computed tomography. The so-called trocar technique must be avoided. Instead, blunt dissection (for tubes >24F) or the Seldinger technique should be used. All chest tubes are connected to a drainage system device: flutter valve, underwater seal, electronic systems or, for indwelling pleural catheters (IPC), vacuum bottles. The classic, three-bottle drainage system requires either (external) wall suction or gravity (“water seal”) drainage (the former not being routinely recommended unless the latter is not effective). The optimal timing for tube removal is still a matter of controversy; however, the use of digital drainage systems facilitates informed and prudent decision-making in that area. A drain-clamping test before tube withdrawal is generally not advocated. Pain, drain blockage and accidental dislodgment are common complications of small-bore drains; the most dreaded complications include organ injury, hemothorax, infections, and re-expansion pulmonary edema. IPC represent a first-line palliative therapy of malignant pleural effusions in many centers. The optimal frequency of drainage, for IPC, has not been formally agreed upon or otherwise officially established. PMID:29372629

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.

[Late endophthalmitis following Ahmed valve].

PubMed

del-Hierro-Zarzuelo, A; Vico-Ruiz, E; Martínez-de-la-Casa, J M; García-Feijoó, J; Castillo-Martín, A; García-Sánchez, J

2005-11-01

A 71-year-old woman with a history of aphakic glaucoma underwent implantation of an Ahmed valve and scleral grafting in her right eye. Postoperative visual acuity was 0.5 and intraocular pressure was 12 mmHg during treatment with brimonidine tartrate (0.2%). Nine months after implantation she suffered a conjunctival infection which was treated with hygienic measures and topical antibiotic therapy. Four days later, she developed an endophthalmitis which was treated with topical, intravitreous and intravenous vancomycin and ceftazidime. The Ahmed drainage implant was replaced at 72 hours. Laboratory culture yielded Haemophilus influenzae. Four days later, the eye was enucleated. Endophthalmitis is an uncommon complication of glaucoma drainage implant surgery. Exposure of the drainage tube represents the greatest risk factor for this condition. Removal of the implant in the first 24 hours is recommended if a good visual prognosis is to be achieved.

A Novel Technique of a Transcorneal Suture to Manage an Iris Tuck into the Tube of a Glaucoma Drainage Device.

PubMed

Kataria, Pankaj; Kaushik, Sushmita; Singh, Simar R; Pandav, Surinder S

2016-08-01

Glaucoma drainage devices create an alternative pathway of aqueous drainage from the anterior chamber by channelling aqueous out of the eye through a tube to a subconjunctival bleb or the suprachoroidal space. They may be associated with a number of potential complications including tube malpositioning. This malpositioning may have serious sequelae such as corneal endothelial damage, chronic iritis, tube iris touch, cataract formation, or tube occlusion. Occlusion of the mouth of the tube by the iris impedes aqueous drainage and results in the failure of intraocular pressure (IOP) control. Tube repositioning in cases of occlusion of the mouth of the tube by the iris often involves extensive and potentially complicated surgery requiring tube removal and reinsertion. We describe a new minimally invasive surgical technique for correcting posterior tube malposition resulting in tube occlusion by the iris. The iris had occluded the tube of a Baerveldt prototype glaucoma drainage devices and caused an intractable increased IOP. After our tube sling suture, the tube was free, and the IOP normalized. The procedure entailed no difficult dissection or major surgical intervention. The technique is illustrated by a surgical video. This novel technique is a simple method that relieved the occlusion successfully, and avoided the need to redissect the conjunctiva or shorten the tube.

Retrograde transcatheter device closure of a complex paravalvular leak after bioprosthetic pulmonary valve replacement in a pediatric patient.

PubMed

Chikkabyrappa, Sathish; Mosca, Ralph S; McElhinney, Doff B

2016-06-01

We report a case of retrograde transcatheter device closure of a complex paravalvular leak (PVL) after bioprosthetic pulmonary valve replacement (PVR) in a 13-year-old patient with congenital pulmonary valve stenosis. There are prior reports of pulmonary PVL closure after PVR in adults (Seery and Slack, Congenit Heart Dis 2014;9:E19-F22), but indications for and technical considerations in PVL closure after bioprosthetic PVR, particularly in children, are not well defined. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Single-center experience and short-term outcome with the JenaValve: a second-generation transapical transcatheter aortic valve implantation device.

PubMed

Reuthebuch, Oliver; Inderbitzin, Devdas Thomas; Rüter, Florian; Jeger, Raban; Kaiser, Christoph; Buser, Peter; Fassl, Jens; Eckstein, Friedrich S

2014-01-01

We present the post-CE(Conformité Européenne)-mark single-center implantation experience and short-term outcome with the second-generation transapical JenaValve transcatheter aortic valve implantation system. Patients [N = 27; 9 women; mean (SD) age, 80.3 (5.5) years] were operated on between November 2011 and August 2012. Via a transapical approach, the valve was positioned, in some cases, repositioned, and finally implanted. All data were collected during the hospital stay. The implantation success rate was 100%; the mean (SD) operation time was 124.7 (43.2) minutes; and the size of the implanted prosthesis was 23 mm (n = 6), 25 mm (n = 14), and 27 mm (n = 7). The in-hospital major adverse cardiac and cerebrovascular events were as follows: intraoperative resuscitation with subsequent aortic rupture (n = 1), postoperative hemorrhage needing revision (n = 1), myocardial infarction (n = 1), atrioventricular block needing a definitive pacemaker (n = 1), new-onset renal failure needing hemodialysis (n = 1), and stroke (n = 1). The 30-day mortality was 11.1% (n = 3). The mean (SD) intensive care unit/total stay was 2.2 (1.7)/11.7 (7.9) days. Postoperative echocardiography [day 6.7 (4.8)] revealed residual paravalvular leakage of trace to grade 1 in 12 patients (44.5%) and no leakage in 15 patients, with a mean (SD) transvalvular pressure gradient of 11.6 (5.6) mm Hg with significant reduction by 36.0 (17.7) mm Hg (P = 0.0001, Wilcoxon signed rank test). This second-generation repositionable transcatheter aortic valve implantation device could safely and successfully be implanted with a fast learning curve, significant reduction in pressure gradients, overall clinical improvement at discharge, as well as an acceptable morbidity and mortality rate in this highest-risk patient cohort.

Heterologous, Fresh, Human Donor Sclera as Patch Graft Material in Glaucoma Drainage Device Surgery.

PubMed

Tsoukanas, Dimitrios; Xanthopoulou, Paraskevi; Charonis, Alexandros C; Theodossiadis, Panagiotis; Kopsinis, Gerasimos; Filippopoulos, Theodoros

2016-07-01

To determine the safety and efficacy of fresh, human sclera allografts as a patch graft material in glaucoma drainage device (GDD) surgery. Retrospective, noncomparative, interventional, consecutive case series. All GDD cases operated between 2008 and 2013 in which fresh human corneoscleral rims were used immediately after the central corneal button was used for penetrating or endothelial keratoplasty. Surgery was performed by 2 surgeons at 2 facilities. The Ahmed Glaucoma Valve (FP-7) was used exclusively in this cohort. Sixty-four eyes of 60 patients were identified; demographic data were recorded along with intraocular pressure (IOP), medication requirements, visual acuity, complications, and subsequent interventions. Incidence of complications. IOP and medication requirements at the last follow-up. Quilified success utilizing Tube Versus Trabeculectomy study criteria. The mean age of the cohort was 66.2±19.1 years; the average preoperative IOP was 33.2±11.1 mm Hg on 4.2±1.3 IOP-lowering agents before GDD surgery. IOP decreased significantly to 14.1±4.7 mm Hg (P<0.001) on 1.6±1.2 IOP-lowering agents (P<0.001) after an average follow-up of 18.2±15.4 months. There were no cases of early or late blebitis or endophthalmitis, and there was 1 case of conjunctival erosion and tube/plate exposure (1.6%) occurring 30 days after surgery. Qualified success was estimated as 90.5% and 81% at 1 and 2 years, respectively, using Tube Versus Trabeculectomy study criteria. Heterologous, fresh, human donor sclera appears to be a safe material for GDD tube coverage. It provides a cost-efficient alternative compared with traditional patch graft materials associated with a low risk of pathogen transmission.

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

46 CFR 64.59 - Spring loaded pressure relief valve.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59... AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59 Spring loaded pressure relief valve. A spring loaded pressure relief valve must— (a) Be set at a nominal...

[Ministernotomy: a preliminary experience in heart valve surgery].

PubMed

Kovarević, Pavle; Mihajlović, Bogoljub; Velicki, Lazar; Redzek, Aleksandar; Ivanović, Vladimir; Komazec, Nikola

2011-05-01

The last decade of the 20th century brought up a significant development in the field of minimally invasive approaches to the valvular heart surgery. Potential benefits of this method are: good esthetic appearance, reduced pain, reduction of postoperative hemorrhage and incidence of surgical site infection, shorter postoperative intensive care units (ICU) period and overall in-hospital period. Partial upper median stemotomy currently presents as a state-of-the art method for minimally invasive surgery of cardiac valves. The aim of this study was to report on initial experience in application of this surgical method in the surgery of mitral and aortic valves. The study was designed and conducted in a prospective manner and included all the patients who underwent minimally invasive cardiac valve surgery through the partial upper median stemotomy during the period November 2008 - August 2009. We analyzed the data on mean age of patients, mean extubation time, mean postoperative drainage, mean duration of hospital stay, as well as on occurance of postoperative complications (postoperative bleeding, surgical site infection and cerebrovascular insult). During the observed period, in the Institute for Cardiovascular Diseases of Vojvodina, Clinic for Cardiovascular Surgery, 17 ministernotomies were performed, with 14 aortic valve replacements (82.35%) and 3 mitral valve replacements (17.65%). Mean age of the patients was 60.78 +/- 12.99 years (64.71% males, 35.29% females). Mean extubation time was 12.53 +/- 8.87 hours with 23.5% of the patients extubated in less than 8 hours. Mean duration of hospital stay was 12.35 +/- 10.17 days (in 29.4% of the patients less than 8 days). Mean postoperative drainage was 547.06 +/- 335.2 mL. Postoperative complications included: bleeding (5.88%) and cerebrovascular insult (5.88%). One patient (5.88%) required conversion to full stemotomy. Partial upper median sternotomy represents the optimal surgical method for the interventions on the

Histological biocompatibility of a stainless steel miniature glaucoma drainage device in humans: a case report.

PubMed

De Feo, Fabio; Jacobson, Stewart; Nyska, Abraham; Pagani, Paola; Traverso, Carlo Enrico

2009-06-01

The purpose of this study was to evaluate the histological biocompatibility of a stainless steel miniature glaucoma drainage device. Twenty-four months before death due to heart failure, this seventy-three-year-old female patient underwent filtration surgery for primary open-angle glaucoma uncontrolled in the right eye. The device was implanted at the limbus under a scleral flap. For histopathological evaluation, two corneoscleral specimens were embedded in methacrylate blocks sectioned to a thickness of 50 microns, polished and stained with periodic acid schiff. Some sections included a longitudinal cross-section of the implant. At the interface between the spur and the flange of the device and the cornea, there was a small shoulder of fibrous tissue. A thin, fibrous capsule covered the remainder of the body of the device up to the distal tip. No inflammatory cells occurred within the fibrous capsule. No material or blockage was noted within the lumen. Our results support the biological inertness of the device.

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...

Comparison of polypropylene and silicone Ahmed® glaucoma valves in the treatment of neovascular glaucoma: A 2-year follow-up.

PubMed

Lubiński, Wojciech; Krzystolik, Karol; Gosławski, Wojciech; Kuprjanowicz, Leszek; Mularczyk, Maciej

2018-01-01

Inflammation associated with biomaterials of Ahmed® glaucoma drainage devices may cause the formation of a capsule around the device and can thus have a significant influence on the level of intraocular pressure reduction. The objective of this study was to compare the clinical outcomes after the implantation of a polypropylene or silicone Ahmed® glaucoma valve in patients with neovascular glaucoma. In the study, 27 eyes with neovascular glaucoma (group 1) received silicon Ahmed® valves and 23 eyes (group 2) received polypropylene valves. The best corrected distance visual acuity (BCDVA), intraocular pressure (IOP) and number of anti-glaucomatous drugs were recorded preoperatively and during a follow-up period of 24 months after surgery. Success was defined by the following criteria: 1) intraocular pressure in the rage of 6-21 mm Hg; 2) IOP reduction of at least 30% relative to preoperative values. All complications were registered. One month postoperatively, the mean BCDVA increased significantly in both groups compared to preoperative values (p < 0.001). These values did not change during the 24 months of follow-up examinations. The probability of success defined by criterion 1 at 24 months of observation was 66.7% for silicone and 27.3% for propylene valves group (p < 0.007). According to criterion 2, the difference in success between the groups was not statistically significant. The total number of complications that occurred in both groups during the 24 months of follow-up examinations was similar, except for a higher occurrence of Tenon's cyst formation in the group with a polypropylene valve (18% vs 35%; p < 0.04). In patients with neovascular glaucoma, the implantation of a silicone valve is associated with a significantly higher probability of long-term reduction of IOP below 21 mm Hg and with a lower risk of valve encapsulation in comparison to polypropylene valves. The obtained results suggest that silicone Ahmed® valves are more effective in the

Coupling of HRT II and AS-OCT to evaluate corneal endothelial cell loss and in vivo visualization of the Ahmed glaucoma valve implant.

PubMed

Mendrinos, E; Dosso, A; Sommerhalder, J; Shaarawy, T

2009-09-01

To report corneal endothelial cell loss and in vivo visualization of the Ahmed glaucoma valve implant in eyes with refractory glaucoma. Ten eyes underwent Ahmed valve implant surgery and were followed-up for 12 months. Data collected included intraocular pressure (IOP), number of antiglaucoma medications and surgery-related complications. At 6 and 12 months postoperatively, the intracameral length of the drainage tube (ICL) and the distance between the tube and the cornea (T-C distance), and the iris (T-I distance) were assessed using anterior segment optical coherence tomography (AS-OCT). Heidelberg cornea tomograph II (HRT II) was used to measure the corneal endothelial cell density. Mean (+/-SEM) preoperative IOP was 29.5+/-4 mmHg. Mean postoperative IOP was 11.6+/-2 at 12 months (P<0.01). Over a 6-month period, mean corneal endothelial loss was 7.9%+/-2.5 in the central and 7.5%+/-2.4 in the peripheral cornea (P<0.01). There was no correlation between central or peripheral corneal endothelial cell loss and the T-C, T-I distance or the ICL of the tube. Corneal endothelial cell loss occurs following Ahmed valve implant surgery, this appears to be multifactorial. AS-OCT and HRT II are promising methods for the follow-up of patients with a glaucoma drainage device.

Hybrid textile heart valve prosthesis: preliminary in vitro evaluation.

PubMed

Vaesken, Antoine; Pidancier, Christian; Chakfe, Nabil; Heim, Frederic

2016-09-22

Transcatheter aortic valve implantation (TAVI) is nowadays a popular alternative technique to surgical valve replacement for critical patients. Biological valve tissue has been used in these devices for over a decade now with over 100,000 implantations. However, material degradations due to crimping for catheter insertion purpose have been reported, and with only 6-year follow-up, no information is available about the long-term durability of biological tissue. Moreover, expensive biological tissue harvesting and chemical treatment procedures tend to promote the development of synthetic valve leaflet materials. Textile polyester (PET) material is characterized by outstanding folding and strength properties combined with proven biocompatibility and could therefore be considered as a candidate to replace biological valve leaflets in TAVI devices. Nevertheless, the material should be preferentially partly elastic in order to limit water hammer effects at valve closing time and prevent exaggerated stress from occurring into the stent and the valve. The purpose of the present work is to study in vitro the mechanical as well as the hydrodynamic behavior of a hybrid elastic textile valve device combining non-deformable PET yarn and elastic polyurethane (PU) yarn. The hybrid valve properties are compared with those of a non-elastic textile valve. Testing results show improved hydrodynamic properties with the elastic construction. However, under fatigue conditions, the interaction between PU and PET yarns tends to limit the valve durability.

Low-Cost Rapid Prototyping of Liquid Crystal Polymer Based Magnetic Microactuators for Glaucoma Drainage Devices

PubMed Central

Park, Hyunsu; John, Simon; Lee, Hyowon

2017-01-01

Glaucoma is one of the leading causes of blindness in the world. Although there is no cure for glaucoma, pharmaceutical or surgical interventions are known to delay the progression of this debilitating disease. In recent years, implantation of glaucoma drainage devices (GDD) have increased due to their ability to manage IOP better than other therapeutic approaches. However, only 50% of the implanted devices remain functional after 5 years often due to biofouling. Here, we report our latest progress towards developing self-clearing GDDs using integrated magnetic microactuators. Our hypothesis is that these magnetic microdevices can provide local mechanical perturbations to prophylactically remove biological accumulation. To reduce the cost and increase the throughput of fabrication, we utilize a maskless photolithography setup and commercially available liquid crystal polymer foils to create prototype devices. The mechanical response of the devices is reported and compared with the theoretical values. PMID:28269212

Low-cost rapid prototyping of liquid crystal polymer based magnetic microactuators for glaucoma drainage devices.

PubMed

Hyunsu Park; John, Simon; Hyowon Lee

2016-08-01

Glaucoma is one of the leading causes of blindness in the world. Although there is no cure for glaucoma, pharmaceutical or surgical interventions are known to delay the progression of this debilitating disease. In recent years, implantation of glaucoma drainage devices (GDD) have increased due to their ability to manage IOP better than other therapeutic approaches. However, only 50% of the implanted devices remain functional after 5 years often due to biofouling. Here, we report our latest progress towards developing self-clearing GDDs using integrated magnetic microactuators. Our hypothesis is that these magnetic microdevices can provide local mechanical perturbations to prophylactically remove biological accumulation. To reduce the cost and increase the throughput of fabrication, we utilize a maskless photolithography setup and commercially available liquid crystal polymer foils to create prototype devices. The mechanical response of the devices is reported and compared with the theoretical values.

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

Chest Tube Drainage of the Pleural Space: A Concise Review for Pulmonologists.

PubMed

Porcel, José M

2018-04-01

Chest tube insertion is a common procedure usually done for the purpose of draining accumulated air or fluid in the pleural cavity. Small-bore chest tubes (≤14F) are generally recommended as the first-line therapy for spontaneous pneumothorax in non-ventilated patients and pleural effusions in general, with the possible exception of hemothoraces and malignant effusions (for which an immediate pleurodesis is planned). Large-bore chest drains may be useful for very large air leaks, as well as post-ineffective trial with small-bore drains. Chest tube insertion should be guided by imaging, either bedside ultrasonography or, less commonly, computed tomography. The so-called trocar technique must be avoided. Instead, blunt dissection (for tubes >24F) or the Seldinger technique should be used. All chest tubes are connected to a drainage system device: flutter valve, underwater seal, electronic systems or, for indwelling pleural catheters (IPC), vacuum bottles. The classic, three-bottle drainage system requires either (external) wall suction or gravity ("water seal") drainage (the former not being routinely recommended unless the latter is not effective). The optimal timing for tube removal is still a matter of controversy; however, the use of digital drainage systems facilitates informed and prudent decision-making in that area. A drain-clamping test before tube withdrawal is generally not advocated. Pain, drain blockage and accidental dislodgment are common complications of small-bore drains; the most dreaded complications include organ injury, hemothorax, infections, and re-expansion pulmonary edema. IPC represent a first-line palliative therapy of malignant pleural effusions in many centers. The optimal frequency of drainage, for IPC, has not been formally agreed upon or otherwise officially established. Copyright©2018. The Korean Academy of Tuberculosis and Respiratory Diseases.

46 CFR 154.1125 - Pipes, fittings, and valves.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., fitting, and valve for the water spray system must be made of fire resistant and corrosion resistant materials, such as galvanized steel or galvanized iron pipe. (e) Each water spray system must have a means of drainage to prevent corrosion of the system and freezing of accumulated water in subfreezing...

46 CFR 154.1125 - Pipes, fittings, and valves.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., fitting, and valve for the water spray system must be made of fire resistant and corrosion resistant materials, such as galvanized steel or galvanized iron pipe. (e) Each water spray system must have a means of drainage to prevent corrosion of the system and freezing of accumulated water in subfreezing...

Intraocular pressure control of a novel glaucoma drainage device - in vitro and in vivo studies

PubMed Central

Cui, Li-Jun; Li, Di-Chen; Liu, Jian; Zhang, Lei; Xing, Yao

2017-01-01

AIM To evaluate the intraocular pressure (IOP) control of an artificial trabeculum drainage system (ATDS), a newly designed glaucoma drainage device, and postoperative complications in normal rabbit eyes. METHODS Pressure drops in air and fluid of 30 ATDS were measured after being connected to a closed manometric system. Twenty of them were then chosen and implanted randomly into the eyes of 20 rabbits. Postoperative slit-lamp, gonioscopic examination and IOP measurements were recorded periodically. Ultrasound biomicroscopy and B-scan ultrasonography were also used to observe the complications. Eyes were enucleated on day 60. RESULTS Pressure drops of 4.6-9.4 mm Hg were obtained at physiological aqueous flow rates in the tests in vitro. The average postoperative IOP of the experimental eyes (11.6-12.8 mm Hg) was lower than the controls significantly (P<0.05) at each time point. Complications of hemorrhage (n=1), cellulosic exudation (two cases) and local iris congestion (two cases) were observed. The lumina of the devices were devoid of obstructions in all specimens examined and a thin fibrous capsule was found around the endplate. CONCLUSION ATDS reduce IOP effectively. However, further studies on the structure are needed to reduce complications. PMID:28944192

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.

A Simple Device for Morphofunctional Evaluation During Aortic Valve-Sparing Surgery.

PubMed

Leone, Alessandro; Bruno, Piergiorgio; Cammertoni, Federico; Massetti, Massimo

2015-07-01

Valve-sparing operations for the treatment of aortic root disease with a structurally normal aortic valve are increasingly performed as they avoid prosthesis-related complications. Short- and long-term results are critically dependent on perfect intraoperative restoration of valve anatomy and function. Residual aortic regurgitation is the main cause of early failure, and it is the most common motive for reoperation. However, intraoperative morphofunctional valve assessment requires expertise, and only transesophageal echocardiography can provide reliable information. We describe a simple, economic, reproducible hydrostatic test to intraoperatively evaluate valve competency under direct visualization. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Clinical Experience with the M4 Ahmed Glaucoma Drainage Implant.

PubMed

Sluch, Ilya; Gudgel, Brett; Dvorak, Justin; Anne Ahluwalia, Mary; Ding, Kai; Vold, Steve; Sarkisian, Steven

2017-01-01

To evaluate the safety and efficacy of the M4 (porous polyethylene plate) Ahmed Glaucoma Valve (AGV) drainage implant in a multicenter retrospective study. A retrospective chart review of medical records of patients who had undergone the M4 Ahmed valve was performed from January 2013 to April 2015. The primary outcome measure was surgical failure defined as: Less than a 20% reduction in baseline intraocular pressure (IOP) to last follow-up visit, final IOP less than 5 mm Hg or greater than 18 mm Hg, reoperation for glaucoma, or loss of light perception vision. All eyes not meeting the above criteria were defined as success. A total of 291 eyes met all study inclusion criteria. The average follow-up in the study was 6 months (±7.6 months) with 112 patients achieving 12-month follow-up (38.5%). 208 eyes (71.5%) met the study success criteria at final follow-up. No statistically significant spikes in postoperative IOP at 1 and 4 months were detected. The average preoperative IOP was 26.0 on an average of 2.8 medications. At 6 months, the average IOP dropped to 16.7 on 0.9 medications and stayed relatively stable at 15.8 on 1.2 medications at 12-month follow-up. The M4 valve appears to have less of a hypertensive phase compared with the other Ahmed class valves with a similar safety profile. While 71.5% success rate was achieved at final follow-up, the failure rate steadily increased over time. While the M4 production has been discontinued, the porous design of the M4 may avoid a pressure spike in the Ahmed valve class and warrants future investigation for valve design. How to cite this article: Sluch I, Gudgel B, Dvorak J, Ahluwalia MA, Ding K, Vold S, Sarkisian S. Clinical Experience with the M4 Ahmed Glaucoma Drainage Implant. J Curr Glaucoma Pract 2017;11(3):92-96.

Tape underlayment rotary-node (TURN) valves for simple on-chip microfluidic flow control

PubMed Central

Markov, Dmitry A.; Manuel, Steven; Shor, Leslie M.; Opalenik, Susan R.; Wikswo, John P.; Samson, Philip C.

2013-01-01

We describe a simple and reliable fabrication method for producing multiple, manually activated microfluidic control valves in polydimethylsiloxane (PDMS) devices. These screwdriver-actuated valves reside directly on the microfluidic chip and can provide both simple on/off operation as well as graded control of fluid flow. The fabrication procedure can be easily implemented in any soft lithography lab and requires only two specialized tools – a hot-glue gun and a machined brass mold. To facilitate use in multi-valve fluidic systems, the mold is designed to produce a linear tape that contains a series of plastic rotary nodes with small stainless steel machine screws that form individual valves which can be easily separated for applications when only single valves are required. The tape and its valves are placed on the surface of a partially cured thin PDMS microchannel device while the PDMS is still on the soft-lithographic master, with the master providing alignment marks for the tape. The tape is permanently affixed to the microchannel device by pouring an over-layer of PDMS, to form a full-thickness device with the tape as an enclosed underlayment. The advantages of these Tape Underlayment Rotary-Node (TURN) valves include parallel fabrication of multiple valves, low risk of damaging a microfluidic device during valve installation, high torque, elimination of stripped threads, the capabilities of TURN hydraulic actuators, and facile customization of TURN molds. We have utilized these valves to control microfluidic flow, to control the onset of molecular diffusion, and to manipulate channel connectivity. Practical applications of TURN valves include control of loading and chemokine release in chemotaxis assay devices, flow in microfluidic bioreactors, and channel connectivity in microfluidic devices intended to study competition and predator / prey relationships among microbes. PMID:19859812

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.

Conduction Abnormalities and Permanent Pacemaker Implantation After Transcatheter Aortic Valve Replacement Using the Repositionable LOTUS Device: The United Kingdom Experience.

PubMed

Rampat, Rajiv; Khawaja, M Zeeshan; Hilling-Smith, Roland; Byrne, Jonathan; MacCarthy, Philip; Blackman, Daniel J; Krishnamurthy, Arvindra; Gunarathne, Ashan; Kovac, Jan; Banning, Adrian; Kharbanda, Raj; Firoozi, Sami; Brecker, Stephen; Redwood, Simon; Bapat, Vinayak; Mullen, Michael; Aggarwal, Suneil; Manoharan, Ganesh; Spence, Mark S; Khogali, Saib; Dooley, Maureen; Cockburn, James; de Belder, Adam; Trivedi, Uday; Hildick-Smith, David

2017-06-26

The authors report the incidence of pacemaker implantation up to hospital discharge and the factors influencing pacing rate following implantation of the LOTUS bioprosthesis (Boston Scientific, Natick, Massachusetts) in the United Kingdom. Transcatheter aortic valve replacement (TAVR) is associated with a significant need for permanent pacemaker implantation. Pacing rates vary according to the device used. The REPRISE II (Repositionable Percutaneous Replacement of Stenotic Aortic Valve Through Implantation of Lotus Valve System) trial reported a pacing rate of 29% at 30 days after implantation of the LOTUS device. Data were collected retrospectively on 228 patients who had the LOTUS device implanted between March 2013 and February 2015 across 10 centers in the United Kingdom. Twenty-seven patients (12%) had pacemakers implanted pre-procedure and were excluded from the analysis. Patients were aged 81.2 ± 7.7 years; 50.7% were male. The mean pre-procedural QRS duration was 101.7 ± 20.4 ms. More than one-half of the cohort (n = 111, 55%) developed new left bundle branch block (LBBB) following the procedure. Permanent pacemakers were implanted in 64 patients (32%) with a median time to insertion of 3.0 ± 3.4 days. Chief indications for pacing were atrioventricular (AV) block (n = 46, 72%), or LBBB with 1st degree AV block (n = 11, 17%). Amongst those who received a pacemaker following TAVR the pre-procedural electrocardiogram findings included: No conduction disturbance (n = 41, 64%); 1st degree AV block (n = 10, 16%); right bundle branch block (n = 6, 9%) and LBBB (n = 5, 8%). LBBB (but not permanent pacemaker) occurred more frequently in patients who had balloon aortic valvuloplasty before TAVR (odds ratio [OR]: 1.25; p = 0.03). Pre-procedural conduction abnormality (composite of 1st degree AV block, hemiblock, right bundle branch block, LBBB) was independently associated with the need for permanent pacemaker (OR: 2.54; p = 0.048). The absence of

Recently patented transcatheter aortic valves in clinical trials.

PubMed

Neragi-Miandoab, Siyamek; Skripochnik, Edvard; Salemi, Arash; Girardi, Leonard

2013-12-01

The most widely used heart valve worldwide is the Edwards Sapien, which currently has 60% of the worldwide transcatheter aortic valve implantation (TAVI) market. The CoreValve is next in line in popularity, encompassing 35% of the worldwide TAVI market. Although these two valves dominate the TAVI market, a number of newer transcatheter valves have been introduced and others are in early clinical evaluation. The new valves are designed to reduce catheter delivery diameter, improve ease of positioning and sealing, and facilitate repositioning or removal. The most recent transcatheter valves for transapical use include Acurate TA (Symetis), Engager (Medtronic), and JenaValve the Portico (St Jude), Sadra Lotus Medical (Boston Scientific), and the Direct Flow Medical. These new inventions may introduce more effective treatment options for high-risk patients with severe aortic stenosis. Improvements in transcatheter valves and the developing variability among them may allow for more tailored approaches with respect to patient's anatomy, while giving operators the opportunity to choose devices they feel more comfortable with. Moreover, introducing new devices to the market will create a competitive environment among producers that will reduce high prices and expand availability. The present review article includes a discussion of recent patents related to Transcatheter Aortic Valves.

Severe right ventricular and tricuspid valve dysfunction after pericardiocentesis.

PubMed

Kuroda, Maiko; Amano, Masashi; Enomoto, Soichiro; Miyake, Makoto; Kondo, Hirokazu; Tamura, Toshihiro; Kaitani, Kazuaki; Izumi, Chisato; Nakagawa, Yoshihisa

2016-10-01

Pericardiocentesis is performed to treat cardiac tamponade or diagnose the cause of pericardial effusion. Cardiogenic shock with right ventricular (RV) dysfunction is a rare complication after pericardiocentesis. We report a case of an 82-year-old man who suddenly suffered cardiopulmonary arrest 12 h after pericardiocentesis. A transthoracic echocardiogram showed remarkable RV dysfunction and tricuspid valve dysfunction. Tricuspid valve closure was severely impaired, and the tricuspid regurgitation signal showed laminar flow with an early peak. However, after treatment with high-dose inotropic drugs, hemodynamic parameters gradually recovered. A transthoracic echocardiogram performed 24 h later showed improved motion of the RV and the tricuspid valve, resulting in a reduction in tricuspid regurgitation. RV and tricuspid valve dysfunction after pericardiocentesis needs to be recognized as a critical complication. Physicians also need to pay attention to not only the amount of drainage but also underlying RV dysfunction.

Beating heart mitral valve repair with integrated ultrasound imaging

NASA Astrophysics Data System (ADS)

McLeod, A. Jonathan; Moore, John T.; Peters, Terry M.

2015-03-01

Beating heart valve therapies rely extensively on image guidance to treat patients who would be considered inoperable with conventional surgery. Mitral valve repair techniques including the MitrClip, NeoChord, and emerging transcatheter mitral valve replacement techniques rely on transesophageal echocardiography for guidance. These images are often difficult to interpret as the tool will cause shadowing artifacts that occlude tissue near the target site. Here, we integrate ultrasound imaging directly into the NeoChord device. This provides an unobstructed imaging plane that can visualize the valve lea ets as they are engaged by the device and can aid in achieving both a proper bite and spacing between the neochordae implants. A proof of concept user study in a phantom environment is performed to provide a proof of concept for this device.

Valve system incorporating single failure protection logic

DOEpatents

Ryan, Rodger; Timmerman, Walter J. H.

1980-01-01

A valve system incorporating single failure protective logic. The system consists of a valve combination or composite valve which allows actuation or de-actuation of a device such as a hydraulic cylinder or other mechanism, integral with or separate from the valve assembly, by means of three independent input signals combined in a function commonly known as two-out-of-three logic. Using the input signals as independent and redundant actuation/de-actuation signals, a single signal failure, or failure of the corresponding valve or valve set, will neither prevent the desired action, nor cause the undesired action of the mechanism.

Pneumatic Valve Operated by Multiplex Pneumatic Transmission

NASA Astrophysics Data System (ADS)

Nishioka, Yasutaka; Suzumori, Koichi; Kanda, Takefumi; Wakimoto, Shuichi

A pneumatic system has several advantages, which are cheapness, lightweight, and reliability to human and environment. These advantages are adapted to some research areas, such as industrial lines, medical and nursing cares, and rehabilitation tools. However, the pneumatic system needs several devices; compressor, air tube, and control valve. This research aim to downsize pneumatic system. In this paper, a new method of multiplex pneumatic transmission for multi-pneumatic servo system is proposed. The valve for this system consists of two vibrators supported by springs, which was designed with simple and cheap structure. The working principle of the valve is vibrators resonance from multiplex pneumatic transmission and it is possible to work as ON/OFF valves without electric wire. Dynamic simulation was used to confirm the working principle of the resonance driving system. A prototype device confirming the principle was designed and developed based on the simulation. The experiments show that this new control system works very well to control two separated valves through single pneumatic tube.

High pressure capillary micro-fluidic valve device and a method of fabricating same

DOEpatents

Crocker, Robert W [Fremont, CA; Caton, Pamela F [Berkely, CA; Gerhardt, Geoff C [Milbury, MA

2007-04-17

A freeze-thaw valve and a method of micro-machining the freeze-thaw valve is provided and includes a valve housing, wherein the valve housing defines a housing cavity and includes a housing inlet, a housing vent, a capillary tubing inlet and a capillary tubing outlet. A valve body is provided, at least a portion of which is lithographically constructed, wherein the valve body includes a refrigerant inlet, a refrigerant outlet and an expansion chamber. The expansion chamber is disposed to communicate the refrigerant inlet with the refrigerant outlet and includes a restriction region having a flow restriction. Additionally, the valve body is disposed within the housing cavity to form an insulating channel between the valve housing and the valve body.

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.

Development of reversible vas deferens occlusive device: IV. Rigid prosthetic devices.

PubMed

Drueschke, E E; Zaneveld, L J; Burns, M; Rodzen, R; Wingfield, J R; Maness, J H

1975-01-01

Different types of rigid, reversible, vas deferens occlusive devices were developed and evaluated in 14 unilaterally vasectomized dogs. All prosthetic devices had molded silicone rubber bodies, and rigid inflow and outflow tubes. Various techniques for the removal of the vas luminal epithelium, and for the preparation of porous ceramic and etched stainless steel surfaces to encourage tissue ingrowth into the prosthetic device end tubues were attempted. The devices differed in their methods of achieving occlusion. One device used a "rotary stem valve" which had a C-section rotating mechanism; the others used the "shuttle stem valve" which possessed an occlusive element that moved transverse to the axis of flow in the device, thus occluding the device when the stem was depressed. The rotarystem valve was implanted by means of a longitudinal incision. The remaining 13 shuttle stem devices were placed in the vas using either a longitudinal or a transverse implantation. Inno case was sperm transport through the prosthetic devices obtained for more than a few ejaculations.

THERMALLY OPERATED VAPOR VALVE

DOEpatents

Dorward, J.G. Jr.

1959-02-10

A valve is presented for use in a calutron to supply and control the vapor to be ionized. The invention provides a means readily operable from the exterior of the vacuum tank of the apparatuss without mechanical transmission of forces for the quick and accurate control of the ionizing arc by a corresponding control of gas flow theretos thereby producing an effective way of carefully regulating the operation of the calutron. The invention consists essentially of a tube member extending into the charge bottle of a calutron devices having a poppet type valve closing the lower end of the tube. An electrical heating means is provided in the valve stem to thermally vary the length of the stem to regulate the valve opening to control the flow of material from the charge bottle.

A review of design and modeling of magnetorheological valve

NASA Astrophysics Data System (ADS)

Abd Fatah, Abdul Yasser; Mazlan, Saiful Amri; Koga, Tsuyoshi; Zamzuri, Hairi; Zeinali, Mohammadjavad; Imaduddin, Fitrian

2015-01-01

Following recent rapid development of researches in utilizing Magnetorheological (MR) fluid, a smart material that can be magnetically controlled to change its apparent viscosity instantaneously, a lot of applications have been established to exploit the benefits and advantages of using the MR fluid. One of the most important applications for MR fluid in devices is the MR valve, where it uses the popular flow or valve mode among the available working modes for MR fluid. As such, MR valve is widely applied in a lot of hydraulic actuation and vibration reduction devices, among them are dampers, actuators and shock absorbers. This paper presents a review on MR valve, discusses on several design configurations and the mathematical modeling for the MR valve. Therefore, this review paper classifies the MR valve based on the coil configuration and geometrical arrangement of the valve, and focusing on four different mathematical models for MR valve: Bingham plastic, Herschel-Bulkley, bi-viscous and Herschel-Bulkley with pre-yield viscosity (HBPV) models for calculating yield stress and pressure drop in the MR valve. Design challenges and opportunities for application of MR fluid and MR valve are also highlighted in this review. Hopefully, this review paper can provide basic knowledge on design and modeling of MR valve, complementing other reviews on MR fluid, its applications and technologies.

Endoscopic ultrasound-guided biliary drainage

PubMed Central

Chavalitdhamrong, Disaya; Draganov, Peter V

2012-01-01

Endoscopic ultrasound (EUS)-guided biliary drainage has emerged as a minimally invasive alternative to percutaneous and surgical interventions for patients with biliary obstruction who had failed endoscopic retrograde cholangiopancreatography (ERCP). EUS-guided biliary drainage has become feasible due to the development of large channel curvilinear therapeutic echo-endoscopes and the use of real-time ultrasound and fluoroscopy imaging in addition to standard ERCP devices and techniques. EUS-guided biliary drainage is an attractive option because of its minimally invasive, single step procedure which provides internal biliary decompression. Multiple investigators have reported high success and low complication rates. Unfortunately, high quality prospective data are still lacking. We provide detailed review of the use of EUS for biliary drainage from the perspective of practicing endoscopists with specific focus on the technical aspects of the procedure. PMID:22363114

Design and fabrication of chemically robust three-dimensional microfluidic valves.

PubMed

Maltezos, George; Garcia, Erika; Hanrahan, Grady; Gomez, Frank A; Vyawahare, Saurabh; Vyawhare, Saurabh; van Dam, R Michael; Chen, Yan; Scherer, Axel

2007-09-01

A current problem in microfluidics is that poly(dimethylsiloxane) (PDMS), used to fabricate many microfluidic devices, is not compatible with most organic solvents. Fluorinated compounds are more chemically robust than PDMS but, historically, it has been nearly impossible to construct valves out of them by multilayer soft lithography (MSL) due to the difficulty of bonding layers made of "non-stick" fluoropolymers necessary to create traditional microfluidic valves. With our new three-dimensional (3D) valve design we can fabricate microfluidic devices from fluorinated compounds in a single monolithic layer that is resistant to most organic solvents with minimal swelling. This paper describes the design and development of 3D microfluidic valves by molding of a perfluoropolyether, termed Sifel, onto printed wax molds. The fabrication of Sifel-based microfluidic devices using this technique has great potential in chemical synthesis and analysis.

Advanced technology for space shuttle auxiliary propellant valves

NASA Technical Reports Server (NTRS)

Wichmann, H.

1973-01-01

Valves for the gaseous hydrogen/gaseous oxygen shuttle auxiliary propulsion system are required to feature low leakage over a wide temperature range coupled with high cycle life, long term compatibility and minimum maintenance. In addition, those valves used as thruster shutoff valves must feature fast response characteristics to achieve small, repeatable minimum impulse bits. These valve technology problems are solved by developing unique valve components such as sealing closures, guidance devices, and actuation means and by demonstrating two prototype valve concepts. One of the prototype valves is cycled over one million cycles without exceeding a leakage rate of 27 scc's per hour at 450 psia helium inlet pressure throughout the cycling program.

Monovalve with integrated fuel injector and port control valve, and engine using same

DOEpatents

Milam, David M.

2002-01-01

Each cylinder of an internal combustion engine includes a combined gas exchange valve and fuel injector with a port control valve. The port control valve operates to open either an intake passage or an exhaust passage. The operation of the combined device is controlled by a pair of electrical actuators. The device is hydraulically actuated.

System for remotely servicing a top loading captive ball valve

DOEpatents

Berry, Stephen M.; Porter, Matthew L.

1996-01-01

An attachment for facilitating servicing of a valve, the valve including: an assembly composed of a valve seat defining a flow path, a flow control member movable relative to the valve seat for blocking or unblocking the valve seat, and a control device including a stem coupled to the flow control member and operable for moving the flow control member relative to the valve seat; a housing for receiving the assembly, the housing having an opening via which the assembly can be removed from, and installed in, the housing, and the housing having a plurality of threaded studs which surround the opening and project away from the housing; a valve housing cover for closing and sealing the opening in the housing, the cover having a first bore for passage of the stem of the control device when the assembly is installed in the housing and a plurality of second bores each located for passage of a respective stud when the cover closes the opening in the housing. A plurality of threaded nuts are engageable with the studs for securing the cover to the housing when the cover closes the opening in the housing, wherein the attachment comprises: a plurality of nut guide devices removable from the housing and each operatively associated with a respective stud for retaining a respective nut and guiding the respective nut into alignment with the respective stud to enable the respective nut to be rotated into engagement with the respective stud; and aligning the nut guide devices with the studs.

Transcatheter treatment of tricuspid regurgitation by caval valve implantation--experimental evaluation of decellularized tissue valves in central venous position.

PubMed

Lauten, Alexander; Laube, Adrian; Schubert, Harald; Bischoff, Sabine; Nietzsche, Sandor; Horstkötter, Kim; Poudel-Bochmann, Bhawana; Franz, Marcus; Lichtenberg, Artur; Figulla, Hans R; Akhyari, Payam

2015-01-01

Caval valve implantation has been suggested for transcatheter treatment of severe tricuspid regurgitation (TR). Combining the interventional technique with the promising surgical experience with decellularized valves, we sought to evaluate the functional and structural outcome of decellularized pericardial tissue valves (dTVs) in the low-pressure venous circulation in a chronic model of TR. Sixteen pericardial tissue valves were heterotopically implanted in the inferior and superior vena cava in a sheep model (54-98 kg; median 74.5 kg, n = 8) of severe TR. The devices were assembled using self-expanding nitinol stents and bovine pericardia decellularized by a detergent-based protocol (group dTV; n = 8). Glutaraldehyde-fixed pericardial tissue valves served as control (GaTV, n = 8). After 6 months, device function and structural maturation were analyzed using echocardiographic, histologic, immunohistologic, and electron microscopic approaches. After implantation, cardiac output increased significantly from 3.7 ± 1.1 l/min to 4.8 ± 1.1 l/min (P < 0.05) and competent valve function was verified by angiography. At 6 months, angiographic and echocardiographic evaluation revealed moderate to severe regurgitation in all GaTV. In contrast, five of the eight dTVs functioned well with only minor regurgitation. In these animals, autopsy revealed preserved valve structure with tender leaflets without signs of thrombosis or calcification. Conversely, GaTV showed severe degeneration with large calcification areas. Microscopic and histologic analysis confirmed endothelial repopulation in both valve types. However, additional interstitial reseeding was observed in decellularized valves. In the venous circulation in severe TR, decellularized valves show superior functional performance compared to Ga-fixed tissue valves. Macroscopic and microscopic analyses suggest preserved structural integrity and advanced endothelial and interstitial repopulation with

Elastic Valve Using Induced-Charge Electro-Osmosis

NASA Astrophysics Data System (ADS)

Sugioka, Hideyuki

2015-06-01

Biomimic devices using induced-charge electro-osmosis (ICEO) is interesting since they have the possibility to realize high-performance functions with simple structures and with low-energy consumption. Thus, inspired by a cilium, we propose a two-dimensional artificial elastic valve using hydrodynamic force due to ICEO with a thin elastic beam in a microfluidic channel and numerically examine the valving performance. By an implicit strongly coupled simulation technique between a fluid and an elastic structure based on the boundary-element method, along with the thin-double-layer approximation, we realize stable calculations and find that the elastic valve using ICEO functions effectively at high frequency with low applied voltages in a realistic pressure flow. Further, we also examine passive motion of the valve; i.e., it stops a reverse flow effectively and releases a forward flow in the channel. We believe that our device can be used in a wide range of microfluidic applications, such as mixers, pumps, etc.

Exhaust gas bypass valve control for thermoelectric generator

DOEpatents

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

2012-09-04

A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2011-10-01 2011-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

46 CFR 105.10-20 - Pressure vacuum relief valve.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in enclosed... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10...

Reduced-impact sliding pressure control valve for pneumatic hammer drill

DOEpatents

Polsky, Yarom [Oak Ridge, TN; Grubelich, Mark C [Albuquerque, NM; Vaughn, Mark R [Albuquerque, NM

2012-05-15

A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

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.

Self-regulating valve

DOEpatents

Humphreys, D.A.

1982-07-20

A variable, self-regulating valve having a hydraulic loss coefficient proportional to a positive exponential power of the flow rate. The device includes two objects in a flow channel and structure which assures that the distance between the two objects is an increasing function of the flow rate. The range of spacing between the objects is such that the hydraulic resistance of the valve is an increasing function of the distance between the two objects so that the desired hydraulic loss coefficient as a function of flow rate is obtained without variation in the flow area.

Management of chest drainage tubes after lung surgery.

PubMed

Satoh, Yukitoshi

2016-06-01

Since chest tubes have been routinely used to drain the pleural space, particularly after lung surgery, the management of chest tubes is considered to be essential for the thoracic surgeon. The pleural drainage system requires effective drainage, suction, and water-sealing. Another key point of chest tube management is that a water seal is considered to be superior to suction for most air leaks. Nowadays, the most common pleural drainage device attached to the chest tube is the three-bottle system. An electronic chest drainage system has been developed that is effective in standardizing the postoperative management of chest tubes. More liberal use of digital drainage devices in the postoperative management of the pleural space is warranted. The removal of chest tubes is a common procedure occurring almost daily in hospitals throughout the world. Extraction of the tube is usually done at the end of full inspiration or at the end of full expiration. The tube removal technique is not as important as how it is done and the preparation for the procedure. The management of chest tubes must be based on careful observation, the patient's characteristics, and the operative procedures that had been performed.

Optical-to-optical interface device

NASA Technical Reports Server (NTRS)

Jacobson, A. D.; Bleha, W. P.; Miller, L.; Grinberg, J.; Fraas, L.; Margerum, D.

1975-01-01

An investigation was conducted to develop an optical-to-optical interface device capable of performing real-time incoherent-to-incoherent optical image conversion. The photoactivated liquid crystal light valve developed earlier represented a prototype liquid crystal light valve device capable of performing these functions. A device was developed which had high performance and extended lifetime.

Evaluation of the tightness of contact between 
limbal sclera tunnel and tube following Ahmed 
glaucoma valve implantation.

PubMed

Holló, Gábor; Naghizadeh, Farzaneh

2013-01-01

To investigate whether the tightness of contact between the tube and the limbal sclera tunnel can be evaluated with high-magnification anterior segment optical coherence tomography (OCT) imaging following Ahmed glaucoma valve implantation. Tightness between the tube and the limbal sclera tunnel was investigated with the CAM-L cornea lens adapter of the Optovue Fourier-domain OCT (RTVue-OCT) for 21 uncomplicated Ahmed glaucoma valves implanted in 20 eyes of 19 patients with glaucoma. Nineteen valves were implanted 4 to 124 months earlier (late postoperative cases) and 2 valves 1 day prior to the imaging (early postoperative cases). All valves were introduced into the anterior chamber via a limbal sclera tunnel. The limbal intratunnel part of the tube was successfully imaged in all but 2 cases where an additional full-thickness sclera patch was used. In 14 cases, the contact was tight without tube compression. In 
5 cases, the tube was partially compressed but remained open in the limbal sclera tunnel, and redilated behind the limbus. No case with loose contact or peritubular filtration was seen. The posterior run of the tube was successfully imaged in all 19 cases without a full-thickness sclera patch. High-magnification imaging with the CAM- L anterior segment adapter of the RTVue-OCT allows detailed examination of the limbal insertion area of tubes in both the early and late postoperative periods. Therefore this method may potentially be applied for detection of complications related to tube insertion after glaucoma drainage device surgery.

An inkjet-printed electrowetting valve for paper-fluidic sensors.

PubMed

Koo, Charmaine K W; He, Fei; Nugen, Sam R

2013-09-07

Paper-fluidic devices have become an emerging trend for micro total analysis systems (microTAS) in the bioengineering field due to their ability to maintain the rapid, sensitive and specific attributes of microfluidic devices. Subsequently, paper-fluidic devices are also more portable, have a lower production cost and are easier to use. However, one of the obstacles in developing paper fluidic devices is the limited ability to control the rate of fluid flow during an assay. In our project, we use electrowetting on dielectrics where a dielectric, which is normally hydrophobic, is polarized and becomes hydrophilic. We have fabricated paper-fluidic devices by inkjet printing and spraying conductive hydrophobic electrodes/valves in conjunction with conductive hydrophilic electrodes which are able to stop the fluid front of phosphate buffered saline (PBS). The hydrophobic valves were then actuated by an applied potential which altered the fluorinated monolayer on the electrode. As the applied potential between the electrodes was increased, the amount of time for the fluid front to pass the valve decreased because the monolayer was altered faster. However, we did not observe significant differences in time as we increased the distance between the electrodes. The valves were also incorporated in a lateral flow assay where the device was used to detect Saccharomyces cerevisiae rRNA sequences. With the ability to control the fluid flow in a paper-fluidic device, more complex and intricate assays can be developed, which not only can be applied in the biomedical, food and environmental fields, but also can be used in low resource settings for the detection of diseases.

Medical devices of the head, neck, and spine.

PubMed

Hunter, Tim B; Yoshino, Mark T; Dzioba, Robert B; Light, Rick A; Berger, William G

2004-01-01

There are many medical devices used for head, neck, and spinal diseases and injuries, and new devices are constantly being introduced. Many of the newest devices are variations on a previous theme. Knowing the specific name of a device is not important. It is important to recognize the presence of a device and to have an understanding of its function as well as to be able to recognize the complications associated with its use. The article discusses the most common and important devices of the head, neck, and spine, including cerebrospinal fluid shunts and the Codman Hakim programmable valve; subdural drainage catheters, subdural electrodes, intracranial electrodes, deep brain stimulators, and cerebellar electrodes; coils, balloons, adhesives, particles, and aneurysm clips; radiation therapy catheters, intracranial balloons for drug installation, and carmustine wafers; hearing aids, cochlear implants, and ossicular reconstruction prostheses; orbital prostheses, intraocular silicone oil, and lacrimal duct stents; anterior and posterior cervical plates, posterior cervical spine wiring, odontoid fracture fixation devices, cervical collars and halo vests; thoracic and lumbar spine implants, anterior and posterior instrumentation for the thoracic and lumbar spine, vertebroplasty, and artificial disks; spinal column stimulators, bone stimulators, intrathecal drug delivery pumps, and sacral stimulators; dental and facial implant devices; gastric and tracheal tubes; vagus nerve stimulators; lumboperitoneal shunts; and temperature- and oxygen-sensing probes. Copyright RSNA, 2004

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...

Outcomes of fornix-based versus limbus-based conjunctival incisions for glaucoma drainage device implant.

PubMed

Suhr, Abraham W; Lim, Michele C; Brandt, James D; Izquierdo, Juan Carlos; Willits, Neil

2012-01-01

To determine the effect of conjunctival incision location on the long-term efficacy of nonvalved glaucoma drainage devices. We conducted a retrospective review of patients ≥18 years of age with uncontrolled glaucoma [intraocular pressure (IOP) ≥18 mm Hg] who underwent glaucoma drainage device implantation. A comparison was made of a limbal-based (LB-BGI) versus fornix-based (FB-BGI) conjunctival flap during placement of a 350-mm Baerveldt glaucoma implant (AMO, Santa Ana, CA) in subjects with at least 1 year of follow-up data. The primary outcome measure was IOP; secondary outcome measures were medication burden, visual acuity, and surgical complications. One hundred sixty eyes of 147 glaucoma patients were included. Two years after surgery, the IOP in the LB-BGI group was 14.3±5.3 mm Hg and in the FB-BGI group 13.1±4.7 mm Hg (P=0.47). Overall success of IOP control was achieved at the final visit (range 1 to 5 y) in 90% of the LB-BGI group and 87% of the FB-BGI group (P=0.63). The medication burden of the 2 groups at 1 and 2 years after surgery was not statistically significantly different. Worsening of visual acuity by more than 2 lines was not statistically different between the groups 2 years after the surgery and at the final visit (P=0.47, P=0.60, respectively). A greater number of eyes developed endophthalmitis and were more likely to undergo subsequent tube revision in the FB-BGI group, but the differences were not significant. Both incision techniques were equally effective in controlling IOP. Each surgical approach has its advantages and this study suggests that either technique may be used safely and effectively.

System for remotely servicing a top loading captive ball valve

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

Berry, S.M.; Porter, M.L.

1996-06-25

An attachment for facilitating servicing of a valve is disclosed including: an assembly composed of a valve seat defining a flow path, a flow control member movable relative to the valve seat for blocking or unblocking the valve seat, and a control device including a stem coupled to the flow control member and operable for moving the flow control member relative to the valve seat; a housing for receiving the assembly, the housing having an opening via which the assembly can be removed from, and installed in, the housing, and the housing having a plurality of threaded studs which surroundmore » the opening and project away from the housing; a valve housing cover for closing and sealing the opening in the housing, the cover having a first bore for passage of the stem of the control device when the assembly is installed in the housing and a plurality of second bores each located for passage of a respective stud when the cover closes the opening in the housing. A plurality of threaded nuts are engageable with the studs for securing the cover to the housing when the cover closes the opening in the housing, wherein the attachment comprises: a plurality of nut guide devices removable from the housing and each operatively associated with a respective stud for retaining a respective nut and guiding the respective nut into alignment with the respective stud to enable the respective nut to be rotated into engagement with the respective stud; and aligning the nut guide devices with the studs. 7 figs.« less

System for remotely servicing a top loading captive ball valve

DOEpatents

Berry, S.M.; Porter, M.L.

1996-06-25

An attachment for facilitating servicing of a valve is disclosed including: an assembly composed of a valve seat defining a flow path, a flow control member movable relative to the valve seat for blocking or unblocking the valve seat, and a control device including a stem coupled to the flow control member and operable for moving the flow control member relative to the valve seat; a housing for receiving the assembly, the housing having an opening via which the assembly can be removed from, and installed in, the housing, and the housing having a plurality of threaded studs which surround the opening and project away from the housing; a valve housing cover for closing and sealing the opening in the housing, the cover having a first bore for passage of the stem of the control device when the assembly is installed in the housing and a plurality of second bores each located for passage of a respective stud when the cover closes the opening in the housing. A plurality of threaded nuts are engageable with the studs for securing the cover to the housing when the cover closes the opening in the housing, wherein the attachment comprises: a plurality of nut guide devices removable from the housing and each operatively associated with a respective stud for retaining a respective nut and guiding the respective nut into alignment with the respective stud to enable the respective nut to be rotated into engagement with the respective stud; and aligning the nut guide devices with the studs. 7 figs.

Does the valve regulated release of urine from the bladder decrease encrustation and blockage of indwelling catheters by crystalline proteus mirabilis biofilms?

PubMed

Sabbuba, N A; Stickler, D J; Long, M J; Dong, Z; Short, T D; Feneley, R J C

2005-01-01

We tested whether valve regulated, intermittent flow of urine from catheterized bladders decreases catheter encrustation. Laboratory models of the catheterized bladder were infected with Proteus mirabilis. Urine was allowed to drain continuously through the catheters or regulated by valves to drain intermittently at predetermined intervals. The time that catheters required to become blocked was recorded and encrustation was visualized by scanning electron microscopy. When a manual valve was used to drain urine from the bladder at 2-hour intervals 4 times during the day, catheters required significantly longer to become blocked than those on continuous drainage (mean 62.6 vs 35.9 hours, p = 0.039). A similar 1.7-fold increase occurred when urine was drained at 4-hour intervals 3 times daily. Experiments with an automatic valve in which urine was released at 2 or 4-hour intervals through the day and night also showed a significant increase in mean time to blockage compared with continuous drainage (p = 0.001). Scanning electron microscopy confirmed that crystalline biofilm was less extensive on valve regulated catheters. Valve regulated, intermittent flow of urine through catheters increases the time that catheters require to become blocked with crystalline biofilm. The most beneficial effect was recorded when urine was released from the bladder at 4-hour intervals throughout the day and night by an automatic valve.

Pros and cons of transcatheter aortic valve implantation (TAVI).

PubMed

Terré, Juan A; George, Isaac; Smith, Craig R

2017-09-01

Transcatheter aortic valve implantation (TAVI) or replacement (TAVR) was recently approved by the FDA for intermediate risk patients with severe aortic stenosis (AS). This technique was already worldwide adopted for inoperable and high-risk patients. Improved device technology, imaging analysis and operator expertise has reduced the initial worrisome higher complications rate associated with TAVR, making it comparable to surgical aortic valve replacement (SAVR). However, many answers need to be addressed before adoption in lower risk patients. This paper highlights the pros and cons of TAVI based mostly on randomized clinical trials involving the two device platforms approved in the United States. We focused our analysis on metrics that will play a key role in expanding TAVR indication in healthier individuals. We review the significance and gave a perspective on paravalvular leak (PVL), valve performance, valve durability, leaflet thrombosis, stroke and pacemaker requirement.

46 CFR 53.05-5 - Discharge capacities and valve markings.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Discharge capacities and valve markings. 53.05-5 Section 53.05-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-5 Discharge capacities and valve markings. The discharge capacities and valve markings must...

46 CFR 53.05-5 - Discharge capacities and valve markings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Discharge capacities and valve markings. 53.05-5 Section 53.05-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-5 Discharge capacities and valve markings. The discharge capacities and valve markings must...

46 CFR 53.05-5 - Discharge capacities and valve markings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Discharge capacities and valve markings. 53.05-5 Section 53.05-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-5 Discharge capacities and valve markings. The discharge capacities and valve markings must...

46 CFR 53.05-5 - Discharge capacities and valve markings.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Discharge capacities and valve markings. 53.05-5 Section 53.05-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-5 Discharge capacities and valve markings. The discharge capacities and valve markings must...

46 CFR 53.05-5 - Discharge capacities and valve markings.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Discharge capacities and valve markings. 53.05-5 Section 53.05-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-5 Discharge capacities and valve markings. The discharge capacities and valve markings must...

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

Pacemaker implantation rate after transcatheter aortic valve implantation with early and new-generation devices: a systematic review.

PubMed

van Rosendael, Philippe J; Delgado, Victoria; Bax, Jeroen J

2018-06-01

The incidence of new-onset conduction abnormalities requiring permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI) with new-generation prostheses remains debated. This systematic review analyses the incidence of PPI after TAVI with new-generation devices and evaluates the electrical, anatomical, and procedural factors associated with PPI. In addition, the incidence of PPI after TAVI with early generation prostheses was reviewed for comparison. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist, this systematic review screened original articles published between October 2010 and October 2017, reporting on the incidence of PPI after implantation of early and new-generation TAVI prostheses. Of the 1406 original articles identified in the first search for new-generation TAVI devices, 348 articles were examined for full text, and finally, 40 studies (n = 17 139) were included. The incidence of a PPI after the use of a new-generation TAVI prosthesis ranged between 2.3% and 36.1%. For balloon-expandable prostheses, the PPI rate remained low when using an early generation SAPIEN device (ranging between 2.3% and 28.2%), and with the new-generation SAPIEN 3 device, the PPI rate was between 4.0% and 24.0%. For self-expandable prostheses, the PPI rates were higher with the early generation CoreValve device (16.3-37.7%), and despite a reduction in PPI rates with the new Evolut R, the rates remained relatively higher (14.7-26.7%). When dividing the studies according to the highest (>26.0%) and the lowest (<12.1%) quintile of PPI rate, patients within the highest quintile were more frequently women when compared with the lowest quintile group (50.9% vs. 46.3%, P < 0.001). Pre-existent conduction abnormalities (electrical factor), calcification of the left ventricular outflow tract (anatomical factor), and balloon valvuloplasty and depth of implantation (procedural factors) were associated

Single-use thermoplastic microfluidic burst valves enabling on-chip reagent storage

PubMed Central

Rahmanian, Omid D.

2014-01-01

A simple and reliable method for fabricating single-use normally closed burst valves in thermoplastic microfluidic devices is presented, using a process flow that is readily integrated into established workflows for the fabrication of thermoplastic microfluidics. An experimental study of valve performance reveals the relationships between valve geometry and burst pressure. The technology is demonstrated in a device employing multiple valves engineered to actuate at different inlet pressures that can be generated using integrated screw pumps. On-chip storage and reconstitution of fluorescein salt sealed within defined reagent chambers are demonstrated. By taking advantage of the low gas and water permeability of cyclic olefin copolymer, the robust burst valves allow on-chip hermetic storage of reagents, making the technology well suited for the development of integrated and disposable assays for use at the point of care. PMID:25972774

Thrombogenic potential of transcatheter aortic valve implantation with trivial paravalvular leakage

PubMed Central

Siegel, Rolland

2014-01-01

Background Significant paravalvular leakage after transcatheter aortic valve implantation (TAVI) correlates with increased morbidity and mortality, but adverse consequences of trivial paravalvular leakage have stimulated few investigations. Using a unique method distinctly different from other diagnostic approaches, we previously reported elevated backflow velocities of short duration (transients) in mechanical valve closure. In this study, similar transients were found in a transcatheter valve paravalvular leakage avatar. Methods Paravalvular leakage rate (zero to 58 mL/second) and aortic valve incompetence (volumetric back flow/forward flow; zero to 32%) were made adjustable using a mock transcatheter aortic valve device and tested in quasi-steady and pulsatile flow test systems. Projected dynamic valve area (PDVA) from the back illuminated mock transcatheter aortic valve device was measured and regional backflow velocities were derived by dividing volumetric flow rate by the PDVA over the open and closing valve phase and the total closed valve area derived from backflow leakage. Results Aortic incompetence from 1-32% generated negative backflow transients from 8 to 267 meters/second, a range not dissimilar to that measured in mechanical valves with zero paravalvular leakage. Optimal paravalvular leakage was identified; not too small generating high backflow transients, not too large considering volume overload and cardiac energy loss caused by defective valve behavior and fluid motion. Conclusions Thrombogenic potential of transcatheter aortic valves with trivial aortic incompetence and high magnitude regional backflow velocity transients was comparable to mechanical valves. This may have relevance to stroke rate, asymptomatic microembolic episodes and indications for anticoagulation therapy after transcatheter valve insertion. PMID:25333018

Percutaneous pulmonary and tricuspid valve implantations: An update

PubMed Central

Wagner, Robert; Daehnert, Ingo; Lurz, Philipp

2015-01-01

The field of percutaneous valvular interventions is one of the most exciting and rapidly developing within interventional cardiology. Percutaneous procedures focusing on aortic and mitral valve replacement or interventional treatment as well as techniques of percutaneous pulmonary valve implantation have already reached worldwide clinical acceptance and routine interventional procedure status. Although techniques of percutaneous pulmonary valve implantation have been described just a decade ago, two stent-mounted complementary devices were successfully introduced and more than 3000 of these procedures have been performed worldwide. In contrast, percutaneous treatment of tricuspid valve dysfunction is still evolving on a much earlier level and has so far not reached routine interventional procedure status. Taking into account that an “interdisciplinary challenging”, heterogeneous population of patients previously treated by corrective, semi-corrective or palliative surgical procedures is growing inexorably, there is a rapidly increasing need of treatment options besides redo-surgery. Therefore, the review intends to reflect on clinical expansion of percutaneous pulmonary and tricuspid valve procedures, to update on current devices, to discuss indications and patient selection criteria, to report on clinical results and finally to consider future directions. PMID:25914786

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.

Microfluidic droplet sorting using integrated bilayer micro-valves

NASA Astrophysics Data System (ADS)

Chen, Yuncong; Tian, Yang; Xu, Zhen; Wang, Xinran; Yu, Sicong; Dong, Liang

2016-10-01

This paper reports on a microfluidic device capable of sorting microfluidic droplets utilizing conventional bilayer pneumatic micro-valves as sorting controllers. The device consists of two micro-valves placed symmetrically on two sides of a sorting area, each on top of a branching channel at an inclined angle with respect to the main channel. Changes in transmitted light intensity, induced by varying light absorbance by each droplet, are used to divert the droplet from the sorting area into one of the three outlet channels. When no valve is activated, the droplet flows into the outlet channel in the direction of the main channel. When one of the valves is triggered, the flexible membrane of valve will first be deflected. Once the droplet leaves the detection point, the deflected membrane will immediately return to its default flattened position, thereby exerting a drawing pressure on the droplet and deviating it from its original streamline to the outlet on the same side as the valve. This sorting method will be particularly suitable for numerous large-scale integrated microfluidic systems, where pneumatic micro-valves are already used. Only few structural modifications are needed to achieve droplet sorting capabilities in these systems. Due to the mechanical nature of diverting energy applied to droplets, the proposed sorting method may induce only minimal interference to biological species or microorganisms encapsulated inside the droplets that may accompany electrical, optical and magnetic-based techniques.

PMMA/PDMS valves and pumps for disposable microfluidics.

PubMed

Zhang, Wenhua; Lin, Shuichao; Wang, Chunming; Hu, Jia; Li, Cong; Zhuang, Zhixia; Zhou, Yongliang; Mathies, Richard A; Yang, Chaoyong James

2009-11-07

Poly(methyl methacrylate) (PMMA) is gaining in popularity in microfluidic devices because of its low cost, excellent optical transparency, attractive mechanical/chemical properties, and simple fabrication procedures. It has been used to fabricate micromixers, PCR reactors, CE and many other microdevices. Here we present the design, fabrication, characterization and application of pneumatic microvalves and micropumps based on PMMA. Valves and pumps are fabricated by sandwiching a PDMS membrane between PMMA fluidic channel and manifold wafers. Valve closing or opening can be controlled by adjusting the pressure in a displacement chamber on the pneumatic layer via a computer regulated solenoid. The valve provides up to 15.4 microL s(-1) at 60 kPa fluid pressure and seals reliably against forward fluid pressure as high as 60 kPa. A PMMA diaphragm pump can be assembled by simply connecting three valves in series. By varying valve volume or opening time, pumping rates ranging from nL to microL per second can be accurately achieved. The PMMA based valves and pumps were further tested in a disposable automatic nucleic acid extraction microchip to extract DNA from human whole blood. The DNA extraction efficiency was about 25% and the 260 nm/280 nm UV absorption ratio for extracted DNA was 1.72. Because of its advantages of inexpensive, facile fabrication, robust and easy integration, the PMMA valve and pump will find their wide application for fluidic manipulation in portable and disposable microfluidic devices.

Pros and cons of transcatheter aortic valve implantation (TAVI)

PubMed Central

Terré, Juan A.; George, Isaac

2017-01-01

Transcatheter aortic valve implantation (TAVI) or replacement (TAVR) was recently approved by the FDA for intermediate risk patients with severe aortic stenosis (AS). This technique was already worldwide adopted for inoperable and high-risk patients. Improved device technology, imaging analysis and operator expertise has reduced the initial worrisome higher complications rate associated with TAVR, making it comparable to surgical aortic valve replacement (SAVR). However, many answers need to be addressed before adoption in lower risk patients. This paper highlights the pros and cons of TAVI based mostly on randomized clinical trials involving the two device platforms approved in the United States. We focused our analysis on metrics that will play a key role in expanding TAVR indication in healthier individuals. We review the significance and gave a perspective on paravalvular leak (PVL), valve performance, valve durability, leaflet thrombosis, stroke and pacemaker requirement. PMID:29062739

Repeat transcatheter aortic valve implantation using a latest generation balloon-expandable device for treatment of failing transcatheter heart valves.

PubMed

Schaefer, Andreas; Treede, Hendrik; Seiffert, Moritz; Deuschl, Florian; Schofer, Niklas; Schneeberger, Yvonne; Blankenberg, Stefan; Reichenspurner, Hermann; Schaefer, Ulrich; Conradi, Lenard

2016-01-15

Paravalvular leakage (PVL) is a known complication of transcatheter aortic valve implantation (TAVI) and is associated with poor outcome. Besides balloon-post-dilatation, valve-in-valve (ViV) procedures can be taken into consideration to control this complication. Herein we present initial experience with use of the latest generation balloon-expandable Edwards Sapien 3® (S3) transcatheter heart valve (THV) for treatment of failing THVs. Between 01/2014 and 12/2014 three patients (two male, age: 71-80 y, log EUROScore I: 11.89 - 32.63) with failing THVs were refered to our institution for further treatment. THV approach with secondary implantation of an S3 was chosen after mutual agreement of the local interdisciplinary heart team at an interval of 533-1119 days from the index procedure. The performed procedures consisted of: S3 in Sapien XT, JenaValve and CoreValve. Successful transfemoral implantation with significant reduction of PVL was achieved in all cases. No intraprocedural complications occurred regarding placement of the S3 with a postprocedural effective orifice area (EOA) of 1.5-2.5 cm(2) and pressure gradients of max/mean 14/6-36/16 mmHg. 30-day mortality was 0%. At the latest follow-up of 90-530 days, all patients are alive and well with satisfactory THV function. Regarding VARC-2 criteria one major bleeding and one TIA was reported. In the instance of moderate or severe aortic regurgitation after TAVI, S3 ViV deployment is an excellent option to reduce residual regurgitation to none or mild. For further assertions concerning functional outcomes long-term results have to be awaited.

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

Acceptance and introduction of disruptive technologies - simple steps to build a fully functional pulmonary valved stent.

PubMed

Huber, Christoph H; Marty, Bettina; von Segesser, Ludwig K

2007-08-01

Valved stents are new land for cardiac surgeons even though they are being used more frequently by interventional disciplines. This paper presents simple steps to build a patient-specific pulmonary valved stent and its delivery device. The design concept was tested by random participants at a med-tech meeting. The valved stent is constructed by linking an endoprosthetic graft with a valved-jugular-vein. The delivery device is made from a modified 5-ml syringe. Of 72 participants, 66 (92%) built and 60 participants implanted the device successfully into the targeted pulmonary position via a trans-infundibular access.

Apical closure device for full-percutaneous transapical valve implantation: stress-test in an animal model†.

PubMed

Ferrari, Enrico; Demertzis, Stefanos; Angelella, Jennifer; Berdajs, Denis; Tozzi, Piergiorgio; Moccetti, Tiziano; Maisano, Francesco; von Segesser, Ludwig K

2017-05-01

Transapical valve implantation is traditionally performed through a left antero-lateral mini-thoracotomy. A self-expandable apical closure device has recently been developed for full-percutaneous transapical valve implantation. We performed haemodynamics stress-tests on an animal model to evaluate the sealing properties. Under general anaesthesia 5 pigs (mean weight: 67 ± 6 Kg) received full heparinization (100 IU/Kg; activated clotting time >250 s and, through inferior mini-sternotomies, 21-Fr introducer sheaths for transapical aortic valve implantation (outer diameter: 25-Fr) were placed over-the-wire in the apexes. Delivery-catheters carrying folded occluders (SAFEX TM final design) were inserted in the introducer sheaths and plugs were then deployed under fluoroscopic guidance. Phase 1: after protamine injection, apical bleeding was monitored for 1 h with standard haemodynamics condition. Phase 2: we induced systemic hypertension with adrenaline infusion to test the sealing properties under stress. Animals were sacrificed after Phase 2 and hearts were removed and inspected. Five plugs were successfully introduced and deployed in 5 pig hearts. Plugs provided good apical sealing in each animal and a mean of 7 ± 4 ml of blood lost per animal was collected during Phase 1: haemodynamics remained stable and no plug dislodgement was detected (mean blood pressure: 52 ± 9 mmHg). During Phase 2, mean systolic and diastolic peak levels reached 268 ± 24 mmHg and 175 ± 17 mmHg, respectively, without plug dislodgment or bleeding. Post-mortem inspection showed good plug deployment and fixation without myocardial damage. The new apical occluder seals large-sized apical access sites in animal models also during induced systemic hypertension. This pilot study is a further step towards full-percutaneous transapical valve procedures in the clinical setting. © The Author 2017. Published by Oxford University Press on behalf of the European

46 CFR 56.50-20 - Pressure relief piping.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND... authorized by the Marine Safety Center. (b) Discharge lines (reproduces 122.6.2(d)). Discharge lines from pressure-relieving safety devices shall be designed to facilitate drainage. (c) Stop valves. Stop valves...

46 CFR 56.50-20 - Pressure relief piping.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND... authorized by the Marine Safety Center. (b) Discharge lines (reproduces 122.6.2(d)). Discharge lines from pressure-relieving safety devices shall be designed to facilitate drainage. (c) Stop valves. Stop valves...

Influence of DC-biasing on the performance of graphene spin valve

NASA Astrophysics Data System (ADS)

Iqbal, Muhammad Zahir; Hussain, Ghulam; Siddique, Salma; Hussain, Tassadaq; Iqbal, Muhammad Javaid

2018-04-01

Generating and controlling the spin valve signal are key factors in 'spintronics', which aims to utilize the spin degree of electrons. For this purpose, spintronic devices are constructed that can detect the spin signal. Here we investigate the effect of direct current (DC) on the magnetoresistance (MR) of graphene spin valve. The DC input not only decreases the magnitude of MR but also distorts the spin valve signal at higher DC inputs. Also, low temperature measurements revealed higher MR for the device, while the magnitude is noticed to decrease at higher temperatures. Furthermore, the spin polarization associated with NiFe electrodes is continuously increased at low DC bias and low temperatures. We also demonstrate the ohmic behavior of graphene spin valve by showing linear current-voltage (I-V) characteristics of the junction. Our findings may contribute significantly in modulating and controlling the spin transport properties of vertical spin valve structures.

Electrical Textile Valves for Paper Microfluidics.

PubMed

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

2017-10-01

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

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

PubMed

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

2016-01-01

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

Magnon Valve Effect between Two Magnetic Insulators.

PubMed

Wu, H; Huang, L; Fang, C; Yang, B S; Wan, C H; Yu, G Q; Feng, J F; Wei, H X; Han, X F

2018-03-02

The key physics of the spin valve involves spin-polarized conduction electrons propagating between two magnetic layers such that the device conductance is controlled by the relative magnetization orientation of two magnetic layers. Here, we report the effect of a magnon valve which is made of two ferromagnetic insulators (YIG) separated by a nonmagnetic spacer layer (Au). When a thermal gradient is applied perpendicular to the layers, the inverse spin Hall voltage output detected by a Pt bar placed on top of the magnon valve depends on the relative orientation of the magnetization of two YIG layers, indicating the magnon current induced by the spin Seebeck effect at one layer affects the magnon current in the other layer separated by Au. We interpret the magnon valve effect by the angular momentum conversion and propagation between magnons in two YIG layers and conduction electrons in the Au layer. The temperature dependence of the magnon valve ratio shows approximately a power law, supporting the above magnon-electron spin conversion mechanism. This work opens a new class of valve structures beyond the conventional spin valves.

Magnon Valve Effect between Two Magnetic Insulators

NASA Astrophysics Data System (ADS)

Wu, H.; Huang, L.; Fang, C.; Yang, B. S.; Wan, C. H.; Yu, G. Q.; Feng, J. F.; Wei, H. X.; Han, X. F.

2018-03-01

The key physics of the spin valve involves spin-polarized conduction electrons propagating between two magnetic layers such that the device conductance is controlled by the relative magnetization orientation of two magnetic layers. Here, we report the effect of a magnon valve which is made of two ferromagnetic insulators (YIG) separated by a nonmagnetic spacer layer (Au). When a thermal gradient is applied perpendicular to the layers, the inverse spin Hall voltage output detected by a Pt bar placed on top of the magnon valve depends on the relative orientation of the magnetization of two YIG layers, indicating the magnon current induced by the spin Seebeck effect at one layer affects the magnon current in the other layer separated by Au. We interpret the magnon valve effect by the angular momentum conversion and propagation between magnons in two YIG layers and conduction electrons in the Au layer. The temperature dependence of the magnon valve ratio shows approximately a power law, supporting the above magnon-electron spin conversion mechanism. This work opens a new class of valve structures beyond the conventional spin valves.

Module isolation devices

DOEpatents

Carolan, Michael Francis; Cooke, John Albert; Buzinski, Michael David

2010-04-27

A gas flow isolation device includes a gas flow isolation valve movable from an opened condition to a closed condition. The module isolation valve in one embodiment includes a rupture disk in flow communication with a flow of gas when the module isolation valve is in an opened condition. The rupture disk ruptures when a predetermined pressure differential occurs across it causing the isolation valve to close. In one embodiment the valve is mechanically linked to the rupture disk to maintain the valve in an opened condition when the rupture disk is intact, and which permits the valve to move into a closed condition when the rupture disk ruptures. In another embodiment a crushable member maintains the valve in an open condition, and the flow of gas passed the valve upon rupturing of the rupture disk compresses the crushable member to close the isolation valve.

21 CFR 878.4200 - Introduction/drainage catheter and accessories.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Introduction/drainage catheter and accessories. 878.4200 Section 878.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4200...

21 CFR 878.4200 - Introduction/drainage catheter and accessories.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Introduction/drainage catheter and accessories. 878.4200 Section 878.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4200...

21 CFR 878.4200 - Introduction/drainage catheter and accessories.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Introduction/drainage catheter and accessories. 878.4200 Section 878.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4200...

21 CFR 878.4200 - Introduction/drainage catheter and accessories.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Introduction/drainage catheter and accessories. 878.4200 Section 878.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4200...

21 CFR 878.4200 - Introduction/drainage catheter and accessories.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Introduction/drainage catheter and accessories. 878.4200 Section 878.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4200...

In Vitro Evaluation of a Novel Hemodynamically Optimized Trileaflet Polymeric Prosthetic Heart Valve

PubMed Central

Claiborne, Thomas E.; Sheriff, Jawaad; Kuetting, Maximilian; Steinseifer, Ulrich; Slepian, Marvin J.; Bluestein, Danny

2013-01-01

Calcific aortic valve disease is the most common and life threatening form of valvular heart disease, characterized by stenosis and regurgitation, which is currently treated at the symptomatic end-stages via open-heart surgical replacement of the diseased valve with, typically, either a xenograft tissue valve or a pyrolytic carbon mechanical heart valve. These options offer the clinician a choice between structural valve deterioration and chronic anticoagulant therapy, respectively, effectively replacing one disease with another. Polymeric prosthetic heart valves (PHV) offer the promise of reducing or eliminating these complications, and they may be better suited for the new transcatheter aortic valve replacement (TAVR) procedure, which currently utilizes tissue valves. New evidence indicates that the latter may incur damage during implantation. Polymer PHVs may also be incorporated into pulsatile circulatory support devices such as total artificial heart and ventricular assist devices that currently employ mechanical PHVs. Development of polymer PHVs, however, has been slow due to the lack of sufficiently durable and biocompatible polymers. We have designed a new trileaflet polymer PHV for surgical implantation employing a novel polymer—xSIBS—that offers superior bio-stability and durability. The design of this polymer PHV was optimized for reduced stresses, improved hemodynamic performance, and reduced thrombogenicity using our device thrombogenicity emulation (DTE) methodology, the results of which have been published separately. Here we present our new design, prototype fabrication methods, hydrodynamics performance testing, and platelet activation measurements performed in the optimized valve prototype and compare it to the performance of a gold standard tissue valve. The hydrodynamic performance of the two valves was comparable in all measures, with a certain advantage to our valve during regurgitation. There was no significant difference between the

A magnetorheological fluid locking device

NASA Astrophysics Data System (ADS)

Kavlicoglu, Barkan; Liu, Yanming

2011-04-01

A magnetorheological fluid (MRF) device is designed to provide a static locking force caused by the operation of a controllable MRF valve. The intent is to introduce an MRF device which provides the locking force of a fifth wheel coupler while maintaining the "powerless" locking capability when required. A passive magnetic field supplied by a permanent magnet provides a powerless locking resistance force. The passively closed MRF valve provides sufficient reaction force to eliminate axial displacement to a pre-defined force value. Unlocking of the device is provided by means of an electromagnet which re-routes the magnetic field distribution along the MR valve, and minimizes the resistance. Three dimensional electromagnetic finite element analyses are performed to optimize the MRF lock valve performance. The MRF locking valve is fabricated and tested for installation on a truck fifth wheel application. An experimental setup, resembling actual working conditions, is designed and tests are conducted on vehicle interface schemes. The powerless-locking capacity and the unlocking process with minimal resistance are experimentally demonstrated.

Monolithic microfabricated valves and pumps by multilayer soft lithography.

PubMed

Unger, M A; Chou, H P; Thorsen, T; Scherer, A; Quake, S R

2000-04-07

Soft lithography is an alternative to silicon-based micromachining that uses replica molding of nontraditional elastomeric materials to fabricate stamps and microfluidic channels. We describe here an extension to the soft lithography paradigm, multilayer soft lithography, with which devices consisting of multiple layers may be fabricated from soft materials. We used this technique to build active microfluidic systems containing on-off valves, switching valves, and pumps entirely out of elastomer. The softness of these materials allows the device areas to be reduced by more than two orders of magnitude compared with silicon-based devices. The other advantages of soft lithography, such as rapid prototyping, ease of fabrication, and biocompatibility, are retained.

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.

Ten years of clinical experience in the use of fixed-pressure versus programmable valves: a retrospective study of 159 patients.

PubMed

Mpakopoulou, Maria; Brotis, Alexandros G; Gatos, Haralampos; Paterakis, Konstantinos; Fountas, Kostas N

2012-01-01

The aim of this study was to present our 10-year experience with the use of fixed-pressure and programmable valves in the treatment of adult patients requiring cerebrospinal fluid (CSF) diversion. Patients (n = 159; 89 male and 70 female) suffering from hydrocephalus of various causes underwent CSF shunt implantation. Forty fixed-pressure and 119 programmable valves were initially implanted. The observed revision rate was 40% in patients with fixed-pressure valves. In 20% of these patients, a revision due to valve mechanism malfunction was undertaken, and the initial valve was replaced with a programmable one. The revision rate in the adjustable-pressure valve subgroup was 20%. The infection rate for the fixed-pressure and programmable valve subgroups were 3%, and 1.7%, respectively. Similarly, subdural fluid collections were noticed in 17% and 4% of patients with fixed-pressure valves and programmable valves, respectively. The revision and over-drainage rates were significantly lower when using programmable valves, and thus, this type of valve is preferred whenever CSF has to be diverted.

Development of myoelectric control type speaking valve with low flow resistance

NASA Astrophysics Data System (ADS)

Ooe, Katsutoshi; Sakurai, Kohei; Mimaki, Shinya

2015-12-01

We aimed to develop welfare devices for patients with phonation disorder. One of these devices is the electrical controltype speaking valve system. The conventional speaking valves have one-way valve architecture, they open when the user breathes in, and they close when user breathes out and produce voices. This type is very simple and tough, but some users feel closeness in case of exhalation without phonation. This problem is caused by its mechanism what can not be controlled by user's will. Therefore, we proposed an electrical control-type speaking valve system to resolve this problem. This valve is controlled by neck myoelectric signal of sternohyoid muscle. From our previous report, it was clarified that this valve had better performance about easy-to-breath. Furthermore, we proposed the compact myoelectric control-type speaking valve system. The new-type speaking valve was enough small to attach the human body, and its opening area is larger than that of conventional one. Additionally, we described the improvement of flow channel shape by using of FEM analysis. According to the result of the analysis, it was clarified that the shape-improved speaking valve gets the low flow resistance channel in case of inspiration. In this report, we tried to make the flow resistance lower by the shape of current plates, in case of both inspiration and exhalation. From the result of FEM analysis, our speaking valve could get better flow channel than older one.

Prosthetic valve endocarditis 7 months after transcatheter aortic valve implantation diagnosed with 3D TEE.

PubMed

Sarı, Cenk; Durmaz, Tahir; Karaduman, Bilge Duran; Keleş, Telat; Bayram, Hüseyin; Baştuğ, Serdal; Özen, Mehmet Burak; Bayram, Nihal Akar; Bilen, Emine; Ayhan, Hüseyin; Kasapkara, Hacı Ahmet; Bozkurt, Engin

2016-01-01

Transcatheter aortic valve implantation (TAVI) was introduced as an alternative treatment for patients with severe symptomatic aortic stenosis for whom surgery would be high-risk. Prosthetic aortic valve endocarditis is a serious complication of surgical AVR (SAVR) with high morbidity and mortality. According to recent cases, post-TAVI prosthetic valve endocarditis (PVE) seems to occur very rarely. We present the case of a 75-year-old woman who underwent TAVI (Edwards Saphien XT) with an uneventful postoperative stay. She was diagnosed with endocarditis using three dimensional (3D) echocardiography on the TAVI device 7 months later and she subsequently underwent surgical aortic valve replacement. Little experience of the interpretation of transoesophageal echocardiography (TEE) and the clinical course and effectiveness of treatment strategies in post-TAVI endocarditis exists. We report a case of PVE in a TAVI patient which was diagnosed with three-dimensional transoesophageal echocardiography (3DTEE). Copyright © 2016 Hellenic Cardiological Society. Published by Elsevier B.V. All rights reserved.

Durability Tests of Ball Valve Prototype with Flowmeter Operation

NASA Astrophysics Data System (ADS)

Rogula, J.; Romanik, G.

2018-02-01

The results of the investigation of the prototypical ball valve are presented in this article. The innovation of the tested valve is a ball with a built-in measuring orifice. The valve has been subjected to durability tests. Leakage under three temperatures: ambient, -30°C and +100°C was analyzed. Sealing elements of the valve were tested for roughness and deviation of shape before and after the cycles of operation. Ball valve operation means cycles of open/close. It was planned to perform 1000 cycles at each temperature condition accordingly. Tests of the valve were performed under gas pressure equal to 10 MPa. The research was carried out under the Operational Program "Intelligent Development" (POIR 01.01.01-00-0013 / 15 "Development of devices for measurement of media flow on industrial trunk-lines".

Candida and cardiovascular implantable electronic devices: a case of lead and native aortic valve endocarditis and literature review.

PubMed

Glavis-Bloom, Justin; Vasher, Scott; Marmor, Meghan; Fine, Antonella B; Chan, Philip A; Tashima, Karen T; Lonks, John R; Kojic, Erna M

2015-11-01

Use of cardiovascular implantable electronic devices (CIED), including permanent pacemakers (PPM) and implantable cardioverter defibrillators (ICD), has increased dramatically over the past two decades. Most CIED infections are caused by staphylococci. Fungal causes are rare and their prognosis is poor. To our knowledge, there has not been a previously reported case of multifocal Candida endocarditis involving both a native left-sided heart valve and a CIED lead. Here, we report the case of a 70-year-old patient who presented with nausea, vomiting, and generalised fatigue, and was found to have Candida glabrata endocarditis involving both a native aortic valve and right atrial ICD lead. We review the literature and summarise four additional cases of CIED-associated Candida endocarditis published from 2009 to 2014, updating a previously published review of cases prior to 2009. We additionally review treatment guidelines and discuss management of CIED-associated Candida endocarditis. © 2015 Blackwell Verlag GmbH.

Next-Generation Transcatheter Heart Valves: Current Trials in Europe and the USA

PubMed Central

Werner, Nikos; Nickenig, Georg

2012-01-01

Transcatheter aortic valve implantation (TAVI) has proven to be a viable alternative for patients with symptomatic severe aortic stenosis who are at high risk for surgical aortic valve replacement. At the same time, there is increasing evidence that moderate-to-severe periprosthetic aortic regurgitation after TAVI is associated with dramatically increased mortality and morbidity. The issue of proper positioning of the valve, including the ability to reposition and recapture the device, must be dealt with before the use of TAVI can be extended to younger, healthier patients. The next generation of transcatheter heart valves will most likely address repositionability to facilitate accurate placement with additional features that minimize paravalvular leakage. Upcoming devices promise to improve outcomes and usability of current TAVI systems. PMID:22891121

40 CFR 63.169 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation...

Code of Federal Regulations, 2010 CFR

2010-07-01

..., and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid...: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid service. (a) Pumps, valves, connectors, and agitators in heavy liquid service...

Early Outcomes of Sutureless Aortic Valves.

PubMed

Hanedan, Muhammet Onur; Mataracı, İlker; Yürük, Mehmet Ali; Özer, Tanıl; Sayar, Ufuk; Arslan, Ali Kemal; Ziyrek, Uğur; Yücel, Murat

2016-06-01

In elderly high-risk surgical patients, sutureless aortic valve replacement (AVR) should be an alternative to standard AVR. The potential advantages of sutureless aortic prostheses include reducing cross-clamping and cardiopulmonary bypass (CPB) time and facilitating minimally invasive surgery and complex cardiac interventions, while maintaining satisfactory hemodynamic outcomes and low rates of paravalvular leakage. The current study reports our single-center experience regarding the early outcomes of sutureless aortic valve implantation. Between October 2012 and June 2015, 65 patients scheduled for surgical valve replacement with symptomatic aortic valve disease and New York Heart Association function of class II or higher were included to this study. Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy) and Edwards Intuity (Edwards Lifesciences, Irvine, CA, USA) valves were used. The mean age of the patients was 71.15±8.60 years. Forty-four patients (67.7%) were female. The average preoperative left ventricular ejection fraction was 56.9±9.93. The CPB time was 96.51±41.27 minutes and the cross-clamping time was 60.85±27.08 minutes. The intubation time was 8.95±4.19 hours, and the intensive care unit and hospital stays were 2.89±1.42 days and 7.86±1.42 days, respectively. The mean quantity of drainage from chest tubes was 407.69±149.28 mL. The hospital mortality rate was 3.1%. A total of five patients (7.69%) died during follow-up. The mean follow-up time was 687.24±24.76 days. The one-year survival rate was over 90%. In the last few years, several models of valvular sutureless bioprostheses have been developed. The present study evaluating the single-center early outcomes of sutureless aortic valve implantation presents the results of an innovative surgical technique, finding that it resulted in appropriate hemodynamic conditions with acceptable ischemic time.

Early Outcomes of Sutureless Aortic Valves

PubMed Central

Hanedan, Muhammet Onur; Mataracı, İlker; Yürük, Mehmet Ali; Özer, Tanıl; Sayar, Ufuk; Arslan, Ali Kemal; Ziyrek, Uğur; Yücel, Murat

2016-01-01

Background In elderly high-risk surgical patients, sutureless aortic valve replacement (AVR) should be an alternative to standard AVR. The potential advantages of sutureless aortic prostheses include reducing cross-clamping and cardiopulmonary bypass (CPB) time and facilitating minimally invasive surgery and complex cardiac interventions, while maintaining satisfactory hemodynamic outcomes and low rates of paravalvular leakage. The current study reports our single-center experience regarding the early outcomes of sutureless aortic valve implantation. Methods Between October 2012 and June 2015, 65 patients scheduled for surgical valve replacement with symptomatic aortic valve disease and New York Heart Association function of class II or higher were included to this study. Perceval S (Sorin Biomedica Cardio Srl, Sallugia, Italy) and Edwards Intuity (Edwards Lifesciences, Irvine, CA, USA) valves were used. Results The mean age of the patients was 71.15±8.60 years. Forty-four patients (67.7%) were female. The average preoperative left ventricular ejection fraction was 56.9±9.93. The CPB time was 96.51±41.27 minutes and the cross-clamping time was 60.85±27.08 minutes. The intubation time was 8.95±4.19 hours, and the intensive care unit and hospital stays were 2.89±1.42 days and 7.86±1.42 days, respectively. The mean quantity of drainage from chest tubes was 407.69±149.28 mL. The hospital mortality rate was 3.1%. A total of five patients (7.69%) died during follow-up. The mean follow-up time was 687.24±24.76 days. The one-year survival rate was over 90%. Conclusion In the last few years, several models of valvular sutureless bioprostheses have been developed. The present study evaluating the single-center early outcomes of sutureless aortic valve implantation presents the results of an innovative surgical technique, finding that it resulted in appropriate hemodynamic conditions with acceptable ischemic time. PMID:27298793

Systematic review and meta-analysis of initial management of pneumothorax in adults: Intercostal tube drainage versus other invasive methods

PubMed Central

Park, Incheol; Kim, Kyung Hwan; Park, Junseok; Shin, Dong Wun

2017-01-01

Objectives The ideal invasive management as initial approach for pneumothorax (PTX) is still under debate. The purpose of this systematic review and meta-analysis was to examine the evidence for the effectiveness of intercostal tube drainage and other various invasive methods as the initial approach to all subtypes of PTX in adults. Methods Three databases were searched from inception to May 29, 2016: MEDLINE, EMBASE, and the Cochrane CENTRAL. Randomised controlled trials that evaluated intercostal tube drainage as the control and various invasive methods as the intervention for the initial approach to PTX in adults were included. The primary outcome was the early success rate of each method, and the risk ratios (RRs) were used for an effect size measure. The secondary outcomes were recurrence rate, hospitalization rate, hospital stay, and complications. Results Seven studies met our inclusion criteria. Interventions were aspiration in six studies and catheterization connected to a one-way valve in one study. Meta-analyses were conducted for early success rate, recurrence rate, hospitalization rate, and hospital stay. Aspiration was inferior to intercostal tube drainage in terms of early success rate (RR = 0.82, confidence interval [CI] = 0.72 to 0.95, I2 = 0%). While aspiration and intercostal tube drainage showed no significant difference in the recurrence rate (RR = 0.84, CI = 0.57 to 1.23, I2 = 0%), aspiration had shorter hospital stay than intercostal tube drainage (mean difference = -1.73, CI = -2.33 to -1.13, I2 = 0%). Aspiration had lower hospitalization rate than intercostal tube drainage, but marked heterogeneity was present (RR = 0.38, CI = 0.19 to 0.76, I2 = 85%). Conclusion Aspiration was inferior to intercostal tube drainage in terms of early resolution, but it had shorter hospital stay. The recurrence rate of aspiration and intercostal tube drainage did not differ significantly. The efficacy of catheterization connected to a one-way valve was

Systematic review and meta-analysis of initial management of pneumothorax in adults: Intercostal tube drainage versus other invasive methods.

PubMed

Kim, Min Joung; Park, Incheol; Park, Joon Min; Kim, Kyung Hwan; Park, Junseok; Shin, Dong Wun

2017-01-01

The ideal invasive management as initial approach for pneumothorax (PTX) is still under debate. The purpose of this systematic review and meta-analysis was to examine the evidence for the effectiveness of intercostal tube drainage and other various invasive methods as the initial approach to all subtypes of PTX in adults. Three databases were searched from inception to May 29, 2016: MEDLINE, EMBASE, and the Cochrane CENTRAL. Randomised controlled trials that evaluated intercostal tube drainage as the control and various invasive methods as the intervention for the initial approach to PTX in adults were included. The primary outcome was the early success rate of each method, and the risk ratios (RRs) were used for an effect size measure. The secondary outcomes were recurrence rate, hospitalization rate, hospital stay, and complications. Seven studies met our inclusion criteria. Interventions were aspiration in six studies and catheterization connected to a one-way valve in one study. Meta-analyses were conducted for early success rate, recurrence rate, hospitalization rate, and hospital stay. Aspiration was inferior to intercostal tube drainage in terms of early success rate (RR = 0.82, confidence interval [CI] = 0.72 to 0.95, I2 = 0%). While aspiration and intercostal tube drainage showed no significant difference in the recurrence rate (RR = 0.84, CI = 0.57 to 1.23, I2 = 0%), aspiration had shorter hospital stay than intercostal tube drainage (mean difference = -1.73, CI = -2.33 to -1.13, I2 = 0%). Aspiration had lower hospitalization rate than intercostal tube drainage, but marked heterogeneity was present (RR = 0.38, CI = 0.19 to 0.76, I2 = 85%). Aspiration was inferior to intercostal tube drainage in terms of early resolution, but it had shorter hospital stay. The recurrence rate of aspiration and intercostal tube drainage did not differ significantly. The efficacy of catheterization connected to a one-way valve was inconclusive because of the small number of

Characterization of a piezoelectric valve for an adaptive pneumatic shock absorber

NASA Astrophysics Data System (ADS)

Mikułowski, Grzegorz; Wiszowaty, Rafał; Holnicki-Szulc, Jan

2013-12-01

This paper describes a pneumatic valve based on a multilayer piezoelectric actuator and Hörbiger plates. The device was designed to operate in an adaptive pneumatic shock absorber. The adaptive pneumatic shock absorber was considered as a piston-cylinder device and the valve was intended to be installed inside the piston. The main objective for the valve application was regulating the gas flow between the cylinder’s chambers in order to maintain the desired value of the reaction force generated by the shock absorber. The paper describes the design constraints and requirements, together with results of analytical modelling of fluid flow verified versus experimentally obtained data. The presented results indicate that the desired performance characteristics of the valve were obtained. The geometrical constraints of the flow ducts were studied and the actuator’s functional features analysed.

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.

Impact of concomitant mitral valve repair for severe mitral regurgitation at the time of continuous-flow left ventricular assist device insertion.

PubMed

Sandoval, Elena; Singh, Steve K; Carillo, Julius A; Baldwin, Andrew C W; Ono, Masahiro; Anand, Jatin; Frazier, O H; Mallidi, Hari R

2017-10-01

Mitral regurgitation (MR) is common in patients with end-stage heart failure. We assessed the effect of performing concomitant mitral valve repair during continuous-flow left ventricular assist device (CF-LVAD) implantation in patients with severe preoperative MR. We performed a single-centre, retrospective review of all patients who underwent CF-LVAD implantation between December 1999 and December 2013 (n = 469). Patients with severe preoperative MR (n = 78) were identified and then stratified according to whether they underwent concomitant valve repair. Univariate and survival analyses were performed, and multivariable regression was used to determine predictors of survival. Of the 78 patients with severe MR, 21 underwent valve repair at the time of CF-LVAD implantation (repair group) and 57 did not (non-repair group). A comparison of the 2 groups showed significant differences between groups: INTERMACS I 16.985 vs 9.52%, (P = 0.039), cardiopulmonary bypass time 82.09 vs 109.4 min (P = 0.0042) and the use of HeartMate II 63.16 vs 100% (P = 0.001). Survival analysis suggested trends towards improved survival and a lower incidence of heart failure-related readmissions in the repair group. Multivariable regression analysis showed no significant independent predictors of survival (mitral valve repair: odds ratio 0.4, 95% confidence interval 0.8-1.5; P = 0.2). Despite the lack of statistical significance, trends towards improved survival and a lower incidence of heart failure events suggest that mitral valve repair may be beneficial in patients undergoing CF-LVAD implantation. Given the known relationship between severe MR and mortality, further study is encouraged to confirm the value of mitral valve repair in these patients. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

1-Year Outcomes After Transcatheter Aortic Valve Replacement With Balloon-Expandable Versus Self-Expandable Valves: Results From the CHOICE Randomized Clinical Trial.

PubMed

Abdel-Wahab, Mohamed; Neumann, Franz-Josef; Mehilli, Julinda; Frerker, Christian; Richardt, Doreen; Landt, Martin; Jose, John; Toelg, Ralph; Kuck, Karl-Heinz; Massberg, Steffen; Robinson, Derek R; El-Mawardy, Mohamed; Richardt, Gert

2015-08-18

The use of a balloon-expandable transcatheter heart valve previously resulted in a greater rate of device success compared with a self-expandable transcatheter heart valve. The aim of this study was to evaluate clinical and echocardiographic outcome data at longer term follow-up. The investigator-initiated trial randomized 241 high-risk patients with symptomatic severe aortic stenosis and anatomy suitable for treatment with both balloon- and self-expandable transcatheter heart valves to transfemoral transcatheter aortic valve replacement with either device. Patients were followed-up for 1 year, with assessment of clinical outcomes and echocardiographic evaluation of valve function. At 1 year, the rates of death of any cause (17.4% vs. 12.8%; relative risk [RR]: 1.35; 95% confidence interval [CI]: 0.73 to 2.50; p = 0.37) and of cardiovascular causes (12.4% vs. 9.4%; RR: 1.32; 95% CI: 0.63 to 2.75; p = 0.54) were not statistically significantly different in the balloon- and self-expandable groups, respectively. The frequencies of all strokes (9.1% vs. 3.4%; RR: 2.66; 95% CI: 0.87 to 8.12; p = 0.11) and repeat hospitalization for heart failure (7.4% vs. 12.8%; RR: 0.58; 95% CI: 0.26 to 1.27; p = 0.19) did not statistically significantly differ between the 2 groups. Elevated transvalvular gradients during follow-up were observed in 4 patients in the balloon-expandable group (3.4% vs. 0%; p = 0.12); all were resolved with anticoagulant therapy, suggesting a thrombotic etiology. More than mild paravalvular regurgitation was more frequent in the self-expandable group (1.1% vs. 12.1%; p = 0.005). Despite the higher device success rate with the balloon-expandable valve, 1-year follow-up of patients in CHOICE (Randomized Comparison of Transcatheter Heart Valves in High Risk Patients With Severe Aortic Stenosis: Medtronic CoreValve Versus Edwards SAPIEN XT Trial), with limited statistical power, revealed clinical outcomes after transfemoral transcatheter aortic valve

3D velocity field characterization of prosthetic heart valve with two different valve testers by means of stereo-PIV.

PubMed

D'Avenio, Giuseppe; Grigioni, Mauro; Daniele, Carla; Morbiducci, Umberto; Hamilton, Kathrin

2015-01-01

Prosthetic heart valves can be associated to mechanical loading of blood, potentially linked to complications (hemolysis and thrombogenicity) which can be clinically relevant. In order to test such devices in pulsatile mode, pulse duplicators (PDs) have been designed and built according to different concepts. This study was carried out to compare anemometric measurements made on the same prosthetic device, with two widely used PDs. The valve (a 27-mm bileaflet valve) was mounted in the aortic section of the PD. The Sheffield University PD and the RWTH Aachen PD were selected as physical models of the circulation. These two PDs differ mainly in the vertical vs horizontal realization, and in the ventricular section, which in the RWTH PD allows for storage of potential energy in the elastic walls of the ventricle. A glassblown aorta, realized according to the geometric data of the same anatomical district in healthy individuals, was positioned downstream of the valve, obtaining 1:1 geometric similarity conditions. A NaI-glycerol-water solution of suitable kinematic viscosity and, at the same time, the proper refractive index, was selected. The flow field downstream of the valve was measured by means of the stereo-PIV (Particle Image Velocimetry) technique, capable of providing the complete 3D velocity field as well as the entire Reynolds stress tensor. The measurements were carried out at the plane intersecting the valve axis. A three-jet profile was clearly found in the plane crossing the leaflets, with both PDs. The extent of the typical recirculation zone in the Valsalva sinus was much larger in the RWTH PD, on account of the different duration of the swirling motion in the ventricular chamber, caused by the elasticity of the ventricle and its geometry. The comparison of the hemodynamical behaviour of the same bileaflet valve tested in two PDs demonstrated the role of the mock loop in affecting the valve performance.

Transcatheter valve-in-valve therapy using 6 different devices in 4 anatomic positions: Clinical outcomes and technical considerations.

PubMed

Conradi, Lenard; Silaschi, Miriam; Seiffert, Moritz; Lubos, Edith; Blankenberg, Stefan; Reichenspurner, Hermann; Schaefer, Ulrich; Treede, Hendrik

2015-12-01

Transcatheter valve-in-valve implantation (ViV) is emerging as a novel treatment option for patients with deteriorated bioprostheses. We report our cumulative experience using 6 types of transcatheter heart valves (THVs) in all anatomic positions. Seventy-five consecutive patients (74.1 ± 12.9 years, 50.7% male (38/75), logEuroSCORE I 26.2% ± 17.8%, STS-PROM 8.8% ± 7.4%) receiving ViV procedures from 2008 to 2014 were included for analysis. Data were prospectively gathered and retrospectively analyzed. ViV was performed in aortic (72.0%, 54/75), mitral (22.7%, 17/75), tricuspid (2.7%, 2/75), and pulmonary (2.7%, 2/75) positions. THVs used were Edwards SAPIEN (XT)/SAPIEN3 (52.0%, 39/75), Medtronic Core Valve/Core Valve Evolut(R) (34.7%, 26/75), St Jude Portico (4.0%, 3/75), Boston Scientific Lotus (4.0%, 3/75), Jena Valve (2.7%, 2/75), and Medtronic Engager (2.7%, 2/75). Interval from index procedure to ViV was 9.3 ± 4.9 years. Access was transapical in 53.3% (40/75), transfemoral (transarterial or transvenous) in 42.7% (32/75), transaortic in 2.7% (2/75), and transjugular in 1.3% (1/75). ViV was successful in 97.3% (73/75) with 2 patients requiring sequential THV implantation for initial malpositioning. Overall immediate procedural (≤72 hours) and all-cause 30-day mortality were 2.7% (2/75) and 8.0% (6/75). Corresponding values after aortic ViV were 1.9% (1/54) and 5.6% (3/54). No periprocedural strokes or cases of coronary obstruction occurred. Paravalvular leakage was less than or equal to mild in all cases. After aortic ViV, gradients were max/mean 34.1 ± 14.2/20.1 ± 7.1 mm Hg and effective orifice area (EOA) was 1.5 ± 1.4 cm(2). Corresponding values after mitral ViV were gradients max/mean 14.2 ± 8.2/4.7 ± 3.1 mm Hg and EOA 2.4 ± 0.9 cm(2). ViV can be performed in all anatomic positions with acceptable hemodynamic and clinical outcome in high-risk patients. Increasing importance of ViV can be anticipated considering growing use of surgical

Valving for controlling a fluid-driven reciprocating apparatus

DOEpatents

Whitehead, John C.

1995-01-01

A pair of control valve assemblies for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve assembly is switched by a pressure signal depending on the state of its counterpart's piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. Each of the valve assemblies uses an intake-exhaust valve and a signal valve with the signal valve of one pump being connected to be pressure responsive to the piston of the opposite cylinder or pump.

Development of a reversible vas deferens occlusive device. VI. Long-term evaluation of flexible prosthetic devices.

PubMed

Brueschke, E E; Zaneveld, L J; Kaleckas, R A; Wingfield, J R

1979-05-01

Fifty-three dogs received implants of several types of flexible devices containing valving mechanisms. These devices were constructed entirely of silicone rubber with the exception of the valve stem, which was made of stainless steel. Generally, the devices were (1) implanted in the open mode and left this way for 27 to 44 months, (2) implanted in the closed mode and kept this way for 11 to 12 months before the valves were reopened, (3) implanted in either the closed or open mode and cycled to the opposite mode every 3 months (four or five cycles), or (4) implanted in either the closed or open mode and cycled to the opposite mode every 6 months (two or three cycles). Different implant methods were also evaluated. Semen analyses were regularly performed on all of the dogs, and a number of the animals were bred during the experiments. It can be concluded that (1) the devices can be opened and closed successfully over long periods, respectively allowing and preventing sperm transport; (2) the breeding ability of the animals is not impaired while the devices are in the open mode, independent of the type of device; (3) the devices do not result in an enhanced incidence of congenital abnormalities in the offspring; and (4) the success rate of device performance does not depend on the method of implanatation used. Thus, the results clearly indicate that the basic mechanism of a soft, reversible valve is a feasible approach to conception control.

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.

Vacuum sealing drainage therapy in the presence of an external fixation device

PubMed Central

Sun, Dahui; Ju, Weina; Wang, Tiejun; Yu, Tiecheng; Qi, Baochang

2016-01-01

Abstract Rationale: Vacuum sealing drainage (VSD) is widely utilized for treating traumatic wounds. Patient concerns: It is particularly difficult and time consuming to use in combination with an external fixator. Diagnoses: This is because the hardware or pins used for fixation interfere with maintaining a seal, resulting in poor adhesion and subsequent air leakage. Interventions: To resolve this problem, we have devised a new method for sealing the wound dressing, while maintaining the required vacuum.When using this technique, a rubber strip is wrapped around each pin in 3 circles outside the plastic drape, and then tightly tied. Outcomes: After completing this procedure, a vacuum is obtained, and any air leakage stops. We employed this technique to treat a cohort of patients in our department over a period of two years, and obtained good healing of soft tissue without air leakage, as well as good clinical outcomes. Lessons: We have observed that patients treated with this method experienced good clinical outcomes without air leakage, and we recommend its use in treating cases where an external fixation device is present. PMID:27861393

Fabrication of Microfluidic Valves Using a Hydrogel Molding Method

NASA Astrophysics Data System (ADS)

Sugiura, Yusuke; Hirama, Hirotada; Torii, Toru

2015-08-01

In this paper, a method for fabricating a microfluidic valve made of polydimethylsiloxane (PDMS) using a rapid prototyping method for microchannels through hydrogel cast molding is discussed. Currently, the valves in microchannels play an important role in various microfluidic devices. The technology to prototype microfluidic valves rapidly is actively being developed. For the rapid prototyping of PDMS microchannels, a method that uses a hydrogel as the casting mold has been recently developed. This technique can be used to prepare a three-dimensional structure through simple and uncomplicated methods. In this study, we were able to fabricate microfluidic valves easily using this rapid prototyping method that utilizes hydrogel cast molding. In addition, we confirmed that the valve displacement could be predicted within a range of constant pressures. Moreover, because microfluidic valves fabricated using this method can be directly observed from a cross-sectional direction, we anticipate that this technology will significantly contribute to clarifying fluid behavior and other phenomena in microchannels and microfluidic valves with complex structures.

Fabrication of Microfluidic Valves Using a Hydrogel Molding Method.

PubMed

Sugiura, Yusuke; Hirama, Hirotada; Torii, Toru

2015-08-24

In this paper, a method for fabricating a microfluidic valve made of polydimethylsiloxane (PDMS) using a rapid prototyping method for microchannels through hydrogel cast molding is discussed. Currently, the valves in microchannels play an important role in various microfluidic devices. The technology to prototype microfluidic valves rapidly is actively being developed. For the rapid prototyping of PDMS microchannels, a method that uses a hydrogel as the casting mold has been recently developed. This technique can be used to prepare a three-dimensional structure through simple and uncomplicated methods. In this study, we were able to fabricate microfluidic valves easily using this rapid prototyping method that utilizes hydrogel cast molding. In addition, we confirmed that the valve displacement could be predicted within a range of constant pressures. Moreover, because microfluidic valves fabricated using this method can be directly observed from a cross-sectional direction, we anticipate that this technology will significantly contribute to clarifying fluid behavior and other phenomena in microchannels and microfluidic valves with complex structures.

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

PubMed

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

2016-01-01

reoperations for TV insufficiency or stenosis. Reoperations on three patients (mean age 42.5 ± 8.7 years) were indicated for aortic valve replacement at 14 months postoperatively (n = 1) and for assist device implantation (n = 2) who eventually underwent heart transplant at 18 and 20 months after TV repair, respectively. The cumulative 12-year survival rate was 86.9%. This double-orifice technique is technically a straightforward repair to abolish TV incompetence with highly satisfactory results, particularly in patients with severe annular dilatation or with leaflet and chordal tethering. In the present series, the technique provided no pitfalls (if the location of the conduction system was borne in mind), requiring only a gentle placement of sutures. It also led to no residual regurgitation or reoperation during the follow up period.

The operating surgeon is an independent predictor of chest tube drainage following cardiac surgery.

PubMed

Dixon, Barry; Reid, David; Collins, Marnie; Newcomb, Andrew E; Rosalion, Alexander; Yap, Cheng-Hon; Santamaria, John D; Campbell, Duncan J

2014-04-01

Bleeding into the chest is a major cause of blood transfusion and adverse outcomes following cardiac surgery. The authors investigated predictors of bleeding following cardiac surgery to identify potentially correctable factors. Data were retrieved from the medical records of patients undergoing cardiac surgery over the period of 2002 to 2008. Multivariate analysis was used to identify the independent predictors of chest tube drainage. Tertiary hospital. Two thousand five hundred seventy-five patients. Cardiac surgery. The individual operating surgeon was independently associated with the extent of chest tube drainage. Other independent factors included internal mammary artery grafting, cardiopulmonary bypass time, urgency of surgery, tricuspid valve surgery, redo surgery, left ventricular impairment, male gender, lower body mass index and higher preoperative hemoglobin levels. Both a history of diabetes and administration of aprotinin were associated with reduced levels of chest tube drainage. The individual operating surgeon was an independent predictor of the extent of chest tube drainage. Attention to surgeon-specific factors offers the possibility of reduced bleeding, fewer transfusions, and improved patient outcomes. © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

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.

Computational Fluid Dynamics Analysis of Thrombosis Potential In Left Ventricular Assist Device Drainage Cannulae

PubMed Central

Fraser, Katharine H; Zhang, Tao; Taskin, M Ertan; Griffith, Bartley P; Wu, Zhongjun J

2010-01-01

Cannulation is necessary when blood is removed from the body, for example in hemodialysis, cardiopulmonary bypass, blood oxygenators, and ventricular assist devices. Artificial blood contacting surfaces are prone to thrombosis, especially in the presence of stagnant or recirculating flow. In this work, computational fluid dynamics was used to investigate the blood flow fields in three clinically available cannulae (Medtronic DLP 12, 16 and 24 F), used as drainage for pediatric circulatory support, and to calculate parameters which may be indicative of thrombosis potential. The results show that using the 24 F cannula below flow rates of about 0.75 l/min produces hemodynamic conditions which may increase the risk of blood clotting within the cannula. No reasons are indicated for not using the 12 or 16 F cannulae with flow rates between 0.25 and 3.0 l/min. PMID:20400890

Red rubber bulb, cheap and effective vacuum drainage.

PubMed

Vatanasapt, V; Areemit, S; Jeeravipoolvarn, P; Kuyyakanond, T; Kuptarnond, C

1989-04-01

Red rubber bulbs have been used for vacuum drainage in head, neck, breast and several other operations by the authors since 1975 quite effectively without any major problems. The vacuum pressure of the red rubber bulbs was found to be higher than the expensive commercially available vacuum wound drainage device. The question of remaining old blood and infective microorganisms inside the reservoir for the reused ones were tested by the manual cleaning process and the standard sterile technique using steam under increased pressure (autoclave). The result is quite satisfactory. We encourage the use of this cheap and effective (made in Thailand) vacuum wound drainage in Thai hospitals and Thai medical schools.

How frequently external ventricular drainage device should be changed in children with ventriculoperitonel shunt infection?

PubMed Central

Gulsen, Ismail; Ak, Hakan; Demir, Nihat; Sosuncu, Enver; Arslan, Mehmet

2015-01-01

Objective: The purpose of the presenting study was to determine how frequently external ventricular drainage (EVD) device should be changed in children with ventriculopertienal shunt (VPS) infection during prolonged intravenous antimicrobial therapy. Methods: In this retrospective study, 25 children with VPS infection were evaluated between January 2012 and December 2013. In these children VPS was surgically removed and appropriate antimicrobial therapy was administered according to cerebrospinal culture results. Data noted about how frequently EVD device had been changed, the number of cells on direct observation of cerebrospinal fluid (CSF), glucose and protein levels of CSF, and CSF culture results were obtained from patients’ records. Results: Total 25 children were included in the study. The median age was three months (1 and 65 months). In 44% of children, Staphylococcus epidermidis was isolated. During treatment period, EVD catheter has changed one to six times. A total of 68 EVD catheters were changed in these patients. When the duration of ventriculostomy catheter and leukocyte count in CSF were evaluated on daily basis, leukocyte count was decreased 5 units per day in children whose catheter remained less than 10 days. However, in children whose catheter remained more than 10 days leukocyte count was decreased 2.21 units per day. Conclusions: In children with VPS infection, EVD device should be changed at every 10 days for the rapid resolution of the infection. PMID:26101506

Prospective study of tricuspid valve regurgitation associated with permanent leads in patients undergoing cardiac rhythm device implantation: Background, rationale, and design

PubMed Central

Dokainish, Hisham; Elbarasi, Esam; Masiero, Simona; Van de Heyning, Caroline; Brambatti, Michela; Ghazal, Sami; AL-Maashani, Said; Capucci, Alessandro; Buikema, Lisanne; Leong, Darryl; Shivalkar, Bharati; Saenen, Johan; Miljoen, Hielko; Morillo, Carlos; Divarakarmenon, Syam; Amit, Guy; Ribas, Sebastian; Brautigam, Aaron; Baiocco, Erika; Maolo, Alessandro; Romandini, Andrea; Maffei, Simone; Connolly, Stuart; Healey, Jeff

2015-01-01

Given the increasing numbers of cardiac device implantations worldwide, it is important to determine whether permanent endocardial leads across the tricuspid valve can promote tricuspid regurgitation (TR). Virtually all current data is retrospective, and indicates a signal of TR being increased after permanent lead implantation. However, the precise incidence of moderate or greater TR post-procedure, the exact mechanisms (mechanical, traumatic, functional), and the hemodynamic burden and clinical effects of this putative increase in TR, remain uncertain. We have therefore designed a multicenter, international, prospective study of 300 consecutive patients (recruitment completed, baseline data presented) who will undergo echocardiography and clinical assessment prior to, and at 1-year post device insertion. This prospective study will help determine whether cardiac device-associated TR is real, what are its potential mechanisms, and whether it has an important clinical impact on cardiac device patients. PMID:26779517

Valves and other mechanical components and equipment: A compilation

NASA Technical Reports Server (NTRS)

1976-01-01

The articles in this Compilation will be of interest to mechanical engineers, users and designers of machinery, and to those engineers and manufacturers specializing in fluid handling systems. Section 1 describes a number of valves and valve systems. Section 2 contains articles on machinery and mechanical devices that may have applications in a number of different areas.

Microfluidic valve array control system integrating a fluid demultiplexer circuit

NASA Astrophysics Data System (ADS)

Kawai, Kentaro; Arima, Kenta; Morita, Mizuho; Shoji, Shuichi

2015-06-01

This paper proposes an efficient control method for the large-scale integration of microvalves in microfluidic systems. The proposed method can control 2n individual microvalves with 2n + 2 control lines (where n is an integer). The on-chip valves are closed by applying pressure to a control line, similar to conventional pneumatic microvalves. Another control line closes gate valves between the control line to the on-chip valves and the on-chip valves themselves, to preserve the state of the on-chip valves. The remaining control lines select an activated gate valve. While the addressed gate valve is selected by the other control lines, the corresponding on-chip valve is actuated by applying input pressure to the control line to the on-chip valves. Using this method would substantially reduce the number of world-to-chip connectors and off-chip valve controllers. Experiments conducted using a fabricated 28 microvalve array device, comprising 256 individual on-chip valves controlled with 18 (2   ×   8 + 2) control lines, yielded switching speeds for the selected on-chip valve under 90 ms.

Electrowetting (EW)-based valve combined with hydrophilic teflon microfluidic guidance in controlling continuous fluid flow.

PubMed

Cheng, Ji-Yen; Hsiung, Lo-Chang

2004-12-01

Electrowetting (EW)-based techniques have been widely used in manipulating discrete liquid. However, few articles discussed the controlling of continuous fluid flow by using EW-based techniques. In this paper, an EW-based valve combined with plasma-modified Teflon surface, which serves as a microfluidic guidance, in controlling continuous fluid flow has been demonstrated. The plasma-modified Teflon surface is firstly demonstrated for confining continuous fluid flow. The EW-based microfluidic device possesses the functions of a valve and a microchannel without complex moving parts and grooved microchannels. The quantitative characteristics of the EW-based valve are also studied. Propylene carbonate (PC) is firstly demonstrated as the working liquid in the EW-based device because of its applications in parallel oligonucleotide synthesis. It is found that lower valve actuation voltage reduces the deterioration of the valve and improves the valve stability.

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

Successful treatment of pure aortic insufficiency with transapical implantation of the JenaValve.

PubMed

Bleiziffer, Sabine; Mazzitelli, Domenico; Nöbauer, Christian; Ried, Thomas; Lange, Rüdiger

2013-08-01

Transcatheter aortic valve implantation was predominantly developed for patients with severe calcified aortic stenosis, as most devices are designed to anchor within the native valve calcium. We report on a patient with pure insufficiency of a non-calcified aortic valve, in whom an anatomically oriented catheter valve was implanted successfully. The design of the prosthesis with position feelers engaging the native aortic valve leaflets proved to be suitable for the treatment of pure aortic insufficiency. Georg Thieme Verlag KG Stuttgart · New York.

Robot-assisted real-time magnetic resonance image-guided transcatheter aortic valve replacement.

PubMed

Miller, Justin G; Li, Ming; Mazilu, Dumitru; Hunt, Tim; Horvath, Keith A

2016-05-01

Real-time magnetic resonance imaging (rtMRI)-guided transcatheter aortic valve replacement (TAVR) offers improved visualization, real-time imaging, and pinpoint accuracy with device delivery. Unfortunately, performing a TAVR in a MRI scanner can be a difficult task owing to limited space and an awkward working environment. Our solution was to design a MRI-compatible robot-assisted device to insert and deploy a self-expanding valve from a remote computer console. We present our preliminary results in a swine model. We used an MRI-compatible robotic arm and developed a valve delivery module. A 12-mm trocar was inserted in the apex of the heart via a subxiphoid incision. The delivery device and nitinol stented prosthesis were mounted on the robot. Two continuous real-time imaging planes provided a virtual real-time 3-dimensional reconstruction. The valve was deployed remotely by the surgeon via a graphic user interface. In this acute nonsurvival study, 8 swine underwent robot-assisted rtMRI TAVR for evaluation of feasibility. Device deployment took a mean of 61 ± 5 seconds. Postdeployment necropsy was performed to confirm correlations between imaging and actual valve positions. These results demonstrate the feasibility of robotic-assisted TAVR using rtMRI guidance. This approach may eliminate some of the challenges of performing a procedure while working inside of an MRI scanner, and may improve the success of TAVR. It provides superior visualization during the insertion process, pinpoint accuracy of deployment, and, potentially, communication between the imaging device and the robotic module to prevent incorrect or misaligned deployment. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Catheter-based tricuspid valve replacement: first experimental data of a newly designed bileaflet stent graft prosthesis.

PubMed

Lausberg, Henning F; Gryszkiewicz, Rafal; Kuetting, Maximilian; Baumgaertner, Moritz; Centola, Marcos; Wendel, Hans-Peter; Nowak-Machen, Martina; Schibilsky, David; Kruger, Tobias; Schlensak, Christian

2017-07-01

Moderate or severe degree tricuspid valve regurgitation (TVR) is associated with high rates of morbidity and mortality. Surgical correction as the only therapeutic option offers unsatisfactory results. Recently, several interventional procedures have been introduced clinically in a limited cohort. We present our initial experiments with an innovative interventional valved stent graft for treatment of TVR. A newly designed porcine pericardium-covered nitinol stent graft with a lateral bicuspid valve was adapted to size in a cadaver study. After haemodynamic testing in an ex vivo perfusion setup, vascular access, valve delivery and function were investigated in an ovine animal model ( n  = 7). The device was implanted successfully in all animals. Vascular access was established surgically via the femoral vein without any vascular complications. Angiography demonstrated the correct position of the device with proper sealing of both venae cavae in 6 animals. In 1 extremely large animal, the position of the device was considered too cranial but still acceptable. Correct valve function was verified in all animals by both angiography and echocardiography. There were no persistent arrhythmias other than during valve implant. All animals survived the implant procedure and were sacrificed electively. This study demonstrated that this new valved stent graft could be delivered safely with correct positioning and valve function in this ovine model. Further long-term studies in animals implanted with the device after creation of tricuspid regurgitation are necessary to prove the haemodynamic benefit of this procedure. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Automated intracranial pressure-controlled cerebrospinal fluid external drainage with LiquoGuard.

PubMed

Linsler, Stefan; Schmidtke, Mareike; Steudel, Wolf Ingo; Kiefer, Michael; Oertel, Joachim

2013-08-01

LiquoGuard is a new device for intracranial pressure (ICP)-controlled drainage of cerebrospinal fluid (CSF). This present study evaluates the accuracy of ICP measurement via the LiquoGuard device in comparison with Spiegelberg. Thus, we compared data ascertained from simultaneous measurement of ICP using tip-transducer and tip-sensor devices. A total of 1,764 monitoring hours in 15 patients (range, 52-219 h) were analysed. All patients received an intraventricular Spiegelberg III probe with the drainage catheter connected to the LiquoGuard system. ICP reading of both devices was performed on an hourly basis. Statistical analysis was done by applying Pearson correlation and Wilcoxon-matched pair test (p < 0.05). Mean ICP values were 11 ± 5 mmHg (Spiegelberg) and 10 ± 7 mmHg (LiquoGuard); the values measured with both devices correlated well (p = 0.001; Pearson correlation =0.349; n = 1,764). In two of the 15 patients with slit ventricles, episodes of significant differences in measured values could be observed. Both patients suffering from slit ventricles failed to produce reliable measurement with the external transducer of the LiquoGuard. LiquoGuard is a valuable new device for ICP-controlled CSF drainage. However, LiquoGuard tends to provide misleading results in slit ventricles. Thus, before these drawbacks are further analysed, the authors recommend additional ICP measurement with internal tip-sensor devices to avoid dangerous erroneous interpretation of ICP data.

Transapical Implantation of a 2nd-Generation JenaValve Device in Patient with Extremely High Surgical Risk

PubMed Central

Mieres, Juan; Menéndez, Marcelo; Fernández-Pereira, Carlos; Rubio, Miguel; Rodríguez, Alfredo E.

2015-01-01

Transcatheter Aortic Valve Replacement (TAVR) is performed in patients who are poor surgical candidates. Many patients have inadequate femoral access, and alternative access sites have been used such as the transapical approach discussed in this paper. We present an elderly and fragile patient not suitable for surgery for unacceptable high risk, including poor ventricular function, previous myocardial infarction with percutaneous coronary intervention, pericardial effusion, and previous cardiac surgery with replacement of mechanical mitral valve. Transapical aortic valve replacement with a second-generation self-expanding JenaValve is performed. The JenaValve is a second-generation transapical TAVR valve consisting of a porcine root valve mounted on a low-profile nitinol stent. The valve is fully retrievable and repositionable. We discuss transapical access, implantation technique, and feasibility of valve implantation in this extremely high surgical risk patient. PMID:26346128

Transapical Implantation of a 2nd-Generation JenaValve Device in Patient with Extremely High Surgical Risk.

PubMed

Mieres, Juan; Menéndez, Marcelo; Fernández-Pereira, Carlos; Rubio, Miguel; Rodríguez, Alfredo E

2015-01-01

Transcatheter Aortic Valve Replacement (TAVR) is performed in patients who are poor surgical candidates. Many patients have inadequate femoral access, and alternative access sites have been used such as the transapical approach discussed in this paper. We present an elderly and fragile patient not suitable for surgery for unacceptable high risk, including poor ventricular function, previous myocardial infarction with percutaneous coronary intervention, pericardial effusion, and previous cardiac surgery with replacement of mechanical mitral valve. Transapical aortic valve replacement with a second-generation self-expanding JenaValve is performed. The JenaValve is a second-generation transapical TAVR valve consisting of a porcine root valve mounted on a low-profile nitinol stent. The valve is fully retrievable and repositionable. We discuss transapical access, implantation technique, and feasibility of valve implantation in this extremely high surgical risk patient.

Adding a custom made pressure release valve during air enema for intussusception: A new technique.

PubMed

Ahmed, Hosni Morsi; Ahmed, Osama; Ahmed, Refaat Khodary

2015-01-01

Non-surgical reduction remains the first line treatment of choice for intussusception. The major complication of air enema reduction is bowel perforation. The authors developed a custom made pressure release valve to be added to portable insufflation devices, delivering air at pressures accepted as safe for effective reduction of intussusception in children under fluoroscopic guidance. The aim of this study was to develop a custom made pressure release valve that is suitable for the insufflation devices used for air enema reduction of intussusception and to put this valve into regular clinical practice. An adjustable, custom made pressure release valve was assembled by the authors using readily available components. The valve was coupled to a simple air enema insufflation device. The device was used for the trial of reduction of intussusception in a prospective study that included 132 patients. The success rate for air enema reduction with the new device was 88.2%. The mean pressure required to achieve complete reduction was 100 mmHg. The insufflation pressure never exceeded the preset value (120 mmHg). Of the successful cases, 58.3% were reduced from the first attempt while 36.1% required a second insufflation. Only 5.55% required a third insufflation to complete the reduction. In cases with unsuccessful pneumatic reduction attempt (18.1%), surgical treatment was required. Surgery ranged from simple reduction to resection with a primary end to end anastomosis. No complications from air enema were recorded. The authors recommend adding pressure release valves to ensure safety by avoiding pressure overshoot during the procedure.

Dynamic tube movement after reimplantation of Ahmed glaucoma valve in a child with glaucoma in aphakia

PubMed Central

Senthil, Sirisha; Badakare, Akshay

2014-01-01

A 10-year-old girl underwent an Ahmed glaucoma valve (AGV) implantation as a primary procedure for glaucoma in aphakia due to congenital cataract surgery. Following an unintended accidental excision of AGV tube during bleb revision for hypertensive phase, AGV was explanted and a second AGV was implanted in the same quadrant after 2 weeks. This resulted in a rare complication of dynamic tube movement in the anterior chamber with tube corneal touch and localised corneal oedema. Excision of the offending unstable tube and placement of a paediatric AGV in a different quadrant led to resolution of this complication, stable vision and well-controlled intraocular pressure. This case highlights the possible causes of dynamic tube, related complications and its management. This case also highlights the importance of understanding the various physiological phases after glaucoma drainage device implantation and their appropriate management. PMID:24695662

Torque limited drive for manual valves

DOEpatents

Elliott, Philip G.; Underwood, Daniel E.

1989-06-06

The present invention is directed to a torque-limiting handwheel device for preventing manual valves from being damaged due to the application of excessive torque during the opening or closing operation of the valves. Torque can only be applied when ridges in the handwheel assembly engage in channels machined in the face of the baseplate. The amount of torque required for disengagement of the ridges from the channels is determined by the force exerted by various Bellville springs and the inclination of the side faces of the channels.

Torque limited drive for manual valves

DOEpatents

Elliott, Philip G.; Underwood, Daniel E.

1989-01-01

The present invention is directed to a torque-limiting handwheel device for preventing manual valves from being damaged due to the application of excessive torque during the opening or closing operation of the valves. Torque can only be applied when ridges in the handwheel assembly engage in channels machined in the face of the baseplate. The amount of torque required for disengagement of the ridges from the channels is determined by the force exerted by various Bellville springs and the inclination of the side faces of the channels.

Centrifugo-pneumatic valving utilizing dissolvable films.

PubMed

Gorkin, Robert; Nwankire, Charles E; Gaughran, Jennifer; Zhang, Xin; Donohoe, Gerard G; Rook, Martha; O'Kennedy, Richard; Ducrée, Jens

2012-08-21

In this article we introduce a novel technology that utilizes specialized water dissolvable thin films for valving in centrifugal microfluidic systems. In previous work (William Meathrel and Cathy Moritz, IVD Technologies, 2007), dissolvable films (DFs) have been assembled in laminar flow devices to form efficient sacrificial valves where DFs simply open by direct contact with liquid. Here, we build on the original DF valving scheme to leverage sophisticated, merely rotationally actuated vapour barriers and flow control for enabling comprehensive assay integration with low-complexity instrumentation on "lab-on-a-disc" platforms. The advanced sacrificial valving function is achieved by creating an inverted gas-liquid stack upstream of the DF during priming of the system. At low rotational speeds, a pocket of trapped air prevents a surface-tension stabilized liquid plug from wetting the DF membrane. However, high-speed rotation disrupts the metastable gas/liquid interface to wet the DF and thus opens the valve. By judicious choice of the radial position and geometry of the valve, the burst frequency can be tuned over a wide range of rotational speeds nearly 10 times greater than those attained by common capillary burst valves based on hydrophobic constrictions. The broad range of reproducible burst frequencies of the DF valves bears the potential for full integration and automation of comprehensive, multi-step biochemical assay protocols. In this report we demonstrate DF valving, discuss the biocompatibility of using the films, and show a potential sequential valving system including the on-demand release of on-board stored liquid reagents, fast centrifugal sedimentation and vigorous mixing; thus providing a viable basis for use in lab-on-a-disc platforms for point-of-care diagnostics and other life science applications.

Utilization, In-Hospital Mortality, and 30-Day Readmission After Percutaneous Mitral Valve Repair in the United States Shortly After Device Approval.

PubMed

Faridi, Kamil F; Popma, Jeffrey J; Strom, Jordan B; Shen, Changyu; Choi, Eunhee; Yeh, Robert W

2018-06-01

The MitraClip device for percutaneous mitral valve repair was approved by the Food and Drug Administration in the United States in October 2013. Few studies have evaluated national outcomes after this procedure in routine clinical practice. We identified adults aged ≥18 years who received percutaneous mitral valve repair from November 2013 to December 2014 in the Nationwide Readmissions Database, a publicly available administrative claims database. Procedural volumes, number of performing hospitals, individual hospital volumes, in-hospital mortality rate, and 30-day hospital readmission rate were determined. Patient demographics, clinical comorbidities, and hospital characteristics were analyzed using logistic regression to determine risk factors for in-hospital death and 30-day readmission. We identified 879 cases performed in the first 14 months after device approval (mean age ± SD, 75.0 ± 13.1 years; 45% women). The number of performing hospitals increased by 5.7-fold (23 to 132), although mean individual hospital volumes remained small (6.2 ± 10.4 cases per hospital). In-hospital all-cause mortality was 3.3% and was associated with higher number of clinical comorbidities. The rate of 30-day readmission was 14.6%, and 6.6% of patients died during rehospitalization. Increased procedural experience was associated with a nonsignificant trend toward reduced hospital readmission after multivariable adjustment (p = 0.08). In conclusion, use of percutaneous mitral valve repair in the United States early after approval increased steadily over time, although individual hospital volumes remained low. More than 1 in 7 patients who underwent this procedure are readmitted within 30 days of discharge. Copyright © 2018 Elsevier Inc. All rights reserved.

High efficiency spin-valve and spin-filter in a doped rhombic graphene quantum dot device

NASA Astrophysics Data System (ADS)

Silva, P. V.; Saraiva-Souza, A.; Maia, D. W.; Souza, F. M.; Filho, A. G. Souza; Meunier, V.; Girão, E. C.

2018-04-01

Spin-polarized transport through a rhombic graphene quantum dot (rGQD) attached to armchair graphene nanoribbon (AGNR) electrodes is investigated by means of the Green's function technique combined with single-band tight-binding (TB) approach including a Hubbard-like term. The Hubbard repulsion was included within the mean-field approximation. Compared to anti-ferromagnetic (AFM), we show that the ferromagnetic (FM) ordering of the rGQD corresponds to a smaller bandgap, thus resulting in an efficient spin injector. As a consequence, the electron transport spectrum reveals a spin valve effect, which is controlled by doping with B/N atoms creating a p-n-type junction. The calculations point out that such systems can be used as spin-filter devices with efficiency close to a 100 % .

A Comparative Result of Ventriculoperitoneal Shunt, Focusing Mainly on Gravity-Assisted Valve and Programmable Valve

PubMed Central

Lee, Won-Chul; Choe, Il-Seung; Park, Sung-Choon; Ha, Young-Soo; Lee, Kyu Chang

2010-01-01

Objective Despite rapid evolution of shunt devices, the complication rates remain high. The most common causes are turning from obstruction, infection, and overdrainage into mainly underdrainage. We investigated the incidence of complications in a consecutive series of hydrocephalic patients. Methods From January 2002 to December 2009, 111 patients underwent ventriculoperitoneal (VP) shunting at our hospital. We documented shunt failures and complications according to valve type, primary disease, and number of revisions. Results Overall shunt survival time was 268 weeks. Mean survival time of gravity-assisted valve (GAV) was 222 weeks versus 286 weeks for other shunts. Survival time of programmable valves (264 weeks) was longer than that of pressure-controlled valves (186 weeks). The most common cause for shunt revision was underdrainage (13 valves). The revision rate due to underdrainage in patients with GAV (7 of 10 patients) was higher than that for other valve types. Of 7 patients requiring revision for GAV underdrainage, 6 patients were bedridden. The overall infection rate was 3.6%, which was lower than reported series. Seven patients demonstrating overdrainage had cranial defects when operations were performed (41%), and overdrainage was improved in 5 patients after cranioplasty. Conclusion Although none of the differences was statistically significant, some of the observations were especially notable. If a candidate for VP shunting is bedridden, GAV may not be indicated because it could lead to underdrainage. Careful procedure and perioperative management can reduce infection rate. Cranioplasty performed prior to VP shunting may be beneficial. PMID:21082054

Valving for controlling a fluid-driven reciprocating apparatus

DOEpatents

Whitehead, J.C.

1995-06-27

A pair of control valve assemblies is described for alternately actuating a pair of fluid-driven free-piston devices by using fluid pressure communication therebetween. Each control valve assembly is switched by a pressure signal depending on the state of its counterpart`s piston. The communication logic is arranged to provide overlap of the forward strokes of the pistons, so that at least one of the pair will always be pressurized. Thus, uninterrupted pumping of liquid is made possible from a pair of free-piston pumps. In addition, the speed and frequency of piston stroking is entirely dependent on the mechanical power load applied. In the case of a pair of pumps, this enables liquid delivery at a substantially constant pressure over the full range of flow rates, from zero to maximum flow. Each of the valve assemblies uses an intake-exhaust valve and a signal valve with the signal valve of one pump being connected to be pressure responsive to the piston of the opposite cylinder or pump. 15 figs.

SU8 diaphragm micropump with monolithically integrated cantilever check valves.

PubMed

Ezkerra, Aitor; Fernández, Luis José; Mayora, Kepa; Ruano-López, Jesús Miguel

2011-10-07

This paper presents a SU8 unidirectional diaphragm micropump with embedded out-of-plane cantilever check valves. The device represents a reliable and low-cost solution for integration of microfluidic control in lab-on-a-chip devices. Its planar architecture allows monolithic definition of its components in a single step and potential integration with previously reported PCR, electrophoresis and flow-sensing SU8 microdevices. Pneumatic actuation is applied on a PDMS diaphragm, which is bonded to the SU8 body at wafer level, further enhancing its integration and mass production capabilities. The cantilever check valves move synchronously with the diaphragm, feature fast response (10ms), low dead volume (86nl) and a 94% flow blockage up to 300kPa. The micropump achieves a maximum flow rate of 177 μl min(-1) at 6 Hz and 200 kPa with an effective area of 10 mm(2). The device is reliable, self-priming and tolerant to particles and big bubbles. To the knowledge of the authors, this is the first micropump in SU8 with monolithically integrated cantilever check valves.

High density 3D printed microfluidic valves, pumps, and multiplexers.

PubMed

Gong, Hua; Woolley, Adam T; Nordin, Gregory P

2016-07-07

In this paper we demonstrate that 3D printing with a digital light processor stereolithographic (DLP-SLA) 3D printer can be used to create high density microfluidic devices with active components such as valves and pumps. Leveraging our previous work on optical formulation of inexpensive resins (RSC Adv., 2015, 5, 106621), we demonstrate valves with only 10% of the volume of our original 3D printed valves (Biomicrofluidics, 2015, 9, 016501), which were already the smallest that have been reported. Moreover, we show that incorporation of a thermal initiator in the resin formulation along with a post-print bake can dramatically improve the durability of 3D printed valves up to 1 million actuations. Using two valves and a valve-like displacement chamber (DC), we also create compact 3D printed pumps. With 5-phase actuation and a 15 ms phase interval, we obtain pump flow rates as high as 40 μL min(-1). We also characterize maximum pump back pressure (i.e., maximum pressure the pump can work against), maximum flow rate (flow rate when there is zero back pressure), and flow rate as a function of the height of the pump outlet. We further demonstrate combining 5 valves and one DC to create a 3-to-2 multiplexer with integrated pump. In addition to serial multiplexing, we also show that the device can operate as a mixer. Importantly, we illustrate the rapid fabrication and test cycles that 3D printing makes possible by implementing a new multiplexer design to improve mixing, and fabricate and test it within one day.

Magnetic timing valves for fluid control in paper-based microfluidics.

PubMed

Li, Xiao; Zwanenburg, Philip; Liu, Xinyu

2013-07-07

Multi-step analytical tests, such as an enzyme-linked immunosorbent assay (ELISA), require delivery of multiple fluids into a reaction zone and counting the incubation time at different steps. This paper presents a new type of paper-based magnetic valves that can count the time and turn on or off a fluidic flow accordingly, enabling timed fluid control in paper-based microfluidics. The timing capability of these valves is realized using a paper timing channel with an ionic resistor, which can detect the event of a solution flowing through the resistor and trigger an electromagnet (through a simple circuit) to open or close a paper cantilever valve. Based on this principle, we developed normally-open and normally-closed valves with a timing period up to 30.3 ± 2.1 min (sufficient for an ELISA on paper-based platforms). Using the normally-open valve, we performed an enzyme-based colorimetric reaction commonly used for signal readout of ELISAs, which requires a timed delivery of an enzyme substrate to a reaction zone. This design adds a new fluid-control component to the tool set for developing paper-based microfluidic devices, and has the potential to improve the user-friendliness of these devices.

Microbial Check Valve for Shuttle

NASA Technical Reports Server (NTRS)

Colombo, G. V.; Putnam, D. F.; Sauer, R. L.

1978-01-01

The Microbial Check Valve (MCV) is a device developed for the Space Shuttle that prevents the transfer of viable microorganisms within water systems. The device is essentially a bed of resin material, impregnated with iodine, that kills microorganisms on contact. It prevents the cross-contamination of microorganisms from a nonpotable system into the potable water system when these systems are interconnected. In this regard, the function of the device is similar to that of the 'air gap' found in conventional one-gravity systems. Basic design data are presented including pressure drop, scaling factors, sizing criteria, and the results of challenging the device with suspensions of seven microorganisms including aerobes, anaerobes and spore formers.

Transcatheter aortic valve replacement: historical perspectives, current evidence, and future directions.

PubMed

Horne, Aaron; Reineck, Elizabeth A; Hasan, Rani K; Resar, Jon R; Chacko, Matthews

2014-10-01

Severe aortic stenosis (AS) results in considerable morbidity and mortality without aortic valve replacement and is expected to increase in prevalence with the aging population. Because AS primarily affects the elderly, many patients with comorbidities are poor candidates for surgical aortic valve replacement (SAVR) and may not be referred. Transcatheter aortic valve replacement (TAVR) has emerged as transformative technology for the management of AS over the past decade. Randomized trials have established the safety and efficacy of TAVR with improved mortality and quality of life compared with medical therapy in inoperable patients, while demonstrating noninferiority and even superiority to SAVR among high-risk operative candidates. However, early studies demonstrated an early penalty of stroke and vascular complications with TAVR as well as increased paravalvular leak as compared with SAVR. Two device platforms have been evaluated and approved for use in the United States: the Edwards SAPIEN and the Medtronic CoreValve. Early studies also suggest cost-effectiveness for TAVR. Ongoing studies are evaluating new iterations of the aforementioned TAVR devices, novel device designs, and applications of TAVR in expanded populations of patients including those with lower risk profiles as well as those with comorbidities that were excluded from early clinical trials. Future improvements in TAVR technology will likely reduce periprocedural and long-term complications. Further studies are needed to confirm device durability over long-term follow-up and explore the applicability of TAVR to broader AS patient populations. Copyright © 2014 Mosby, Inc. All rights reserved.

The use of irradiated corneal patch grafts in pediatric Ahmed drainage implant surgery.

PubMed

Nolan, Kaitlyn Wallace; Lucas, Jordyn; Abbasian, Javaneh

2015-10-01

To describe the use of irradiated cornea for scleral reinforcement in Ahmed glaucoma valve drainage implant (AGV) devices in children. The medical records of patients <18 years of age who underwent AGV surgery with irradiated cornea as scleral reinforcement were reviewed retrospectively. The primary outcome measure was erosion of the drainage tube through the corneal patch graft. Secondary outcome measures included other major complications: persistent inflammation, wound dehiscence, transmission of infectious disease, endophthalmitis, and tube/plate self-explantation. A total of 25 procedures (20 patients) met inclusion criteria. Average patient age was 70 months (range, 2 months to 17 years). Mean follow-up was 24.8 months (range, 6 months to 6.2 years). One tube experienced conjunctival exposure through two separate corneal grafts (2/25 cases [8%]), sequentially in the same eye. The first event occurred at month 3.5 after primary implantation of the tube shunt; the second erosion occurred following revision of the existing implant at month 1.5 postoperatively. There were 2 cases of auto-explantation, 2 cases of wound dehiscence, and 1 case of persistent inflammation. There were no cases of endophthalmitis or other infections. To our knowledge, this is the first report describing the use of corneal patch grafts in children. Irradiated cornea improves cosmesis and enhances visualization of the tube. The risk of tube exposure was found to be low and comparable to other materials used as a patch graft. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

Catheter Ablation of Atrial Fibrillation in Patients with Hardware in the Heart - Septal Closure Devices, Mechanical Valves and More.

PubMed

Bartoletti, Stefano; Santangeli, Pasquale; DI Biase, Luigi; Natale, Andrea

2013-01-01

Patients with mechanical "hardware" in the heart, such as those with mechanical cardiac valves or atrial septal closure devices, represent a population at high risk of developing AF. Catheter ablation of AF in these subjects might represent a challenge, due to the perceived higher risk of complications associated with the presence of intracardiac mechanical devices. Accordingly, such patients were excluded or poorly represented in major trials proving the benefit of catheter ablation for the rhythm-control of AF. However, recent evidence supports the concept that catheter ablation procedures might be equally effective in these patients, without a significant increase in the risk of procedural complications. This review will summarize the current state-of-the-art on catheter ablation of AF in patients with mechanical "hardware" in the heart.

Control device for prosthetic urinary sphincter cuff

NASA Technical Reports Server (NTRS)

Reinicke, Robert H. (Inventor)

1983-01-01

A device for controlling flow of fluid to and from a resilient inflatable cuff implanted about the urethra to control flow of urine therethrough. The device comprises a flexible bulb reservoir and a control unit that includes a manually operated valve that opens automatically when the bulb is squeezed to force fluid into the cuff for closing the urethra. The control unit also includes a movable valve seat member having a relatively large area exposed to pressure of fluid in a chamber that is connected to the cuff and which moves to a position in which the valve member is unseated by an abutment when fluid pressure in the chamber exceeds a predetermined value to thereby relieve excess fluid pressure in the cuff. The arrangement is such that the valve element is held closed against the seat member by the full differential in fluid pressures acting on both sides of the valve element until the seat member is moved away from the valve element to thus insure positive closing of the valve element until the seat member is moved out of engagement with the valve element by excess pressure differential.

Transcatheter Aortic Valve Replacement in Pure Native Aortic Valve Regurgitation.

PubMed

Yoon, Sung-Han; Schmidt, Tobias; Bleiziffer, Sabine; Schofer, Niklas; Fiorina, Claudia; Munoz-Garcia, Antonio J; Yzeiraj, Ermela; Amat-Santos, Ignacio J; Tchetche, Didier; Jung, Christian; Fujita, Buntaro; Mangieri, Antonio; Deutsch, Marcus-Andre; Ubben, Timm; Deuschl, Florian; Kuwata, Shingo; De Biase, Chiara; Williams, Timothy; Dhoble, Abhijeet; Kim, Won-Keun; Ferrari, Enrico; Barbanti, Marco; Vollema, E Mara; Miceli, Antonio; Giannini, Cristina; Attizzani, Guiherme F; Kong, William K F; Gutierrez-Ibanes, Enrique; Jimenez Diaz, Victor Alfonso; Wijeysundera, Harindra C; Kaneko, Hidehiro; Chakravarty, Tarun; Makar, Moody; Sievert, Horst; Hengstenberg, Christian; Prendergast, Bernard D; Vincent, Flavien; Abdel-Wahab, Mohamed; Nombela-Franco, Luis; Silaschi, Miriam; Tarantini, Giuseppe; Butter, Christian; Ensminger, Stephan M; Hildick-Smith, David; Petronio, Anna Sonia; Yin, Wei-Hsian; De Marco, Federico; Testa, Luca; Van Mieghem, Nicolas M; Whisenant, Brian K; Kuck, Karl-Heinz; Colombo, Antonio; Kar, Saibal; Moris, Cesar; Delgado, Victoria; Maisano, Francesco; Nietlispach, Fabian; Mack, Michael J; Schofer, Joachim; Schaefer, Ulrich; Bax, Jeroen J; Frerker, Christian; Latib, Azeem; Makkar, Raj R

2017-12-05

Limited data exist about safety and efficacy of transcatheter aortic valve replacement (TAVR) in patients with pure native aortic regurgitation (AR). This study sought to compare the outcomes of TAVR with early- and new-generation devices in symptomatic patients with pure native AR. From the pure native AR TAVR multicenter registry, procedural and clinical outcomes were assessed according to VARC-2 criteria and compared between early- and new-generation devices. A total of 331 patients with a mean STS score of 6.7 ± 6.7 underwent TAVR. The early- and new-generation devices were used in 119 patients (36.0%) and 212 patients (64.0%), respectively. STS score tended to be lower in the new-generation device group (6.2 ± 6.7 vs. 7.6 ± 6.7; p = 0.08), but transfemoral access was more frequently used in the early-generation device group (87.4% vs. 60.8%; p < 0.001). Compared with the early-generation devices, the new-generation devices were associated with a significantly higher device success rate (81.1% vs. 61.3%; p < 0.001) due to lower rates of second valve implantation (12.7% vs. 24.4%; p = 0.007) and post-procedural AR ≥ moderate (4.2% vs. 18.8%; p < 0.001). There were no significant differences in major 30-day endpoints between the 2 groups. The cumulative rates of all-cause and cardiovascular death at 1-year follow-up were 24.1% and 15.6%, respectively. The 1-year all-cause mortality rate was significantly higher in the patients with post-procedural AR ≥ moderate compared with those with post-procedural AR ≤ mild (46.1% vs. 21.8%; log-rank p = 0.001). On multivariable analysis, post-procedural AR ≥ moderate was independently associated with 1-year all-cause mortality (hazard ratio: 2.85; 95% confidence interval: 1.52 to 5.35; p = 0.001). Compared with the early-generation devices, TAVR using the new-generation devices was associated with improved procedural outcomes in treating patients with pure native AR. In patients with pure native AR

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.

SSh versus TSE sequence protocol in rapid MR examination of pediatric patients with programmable drainage system.

PubMed

Brichtová, Eva; Šenkyřík, J

2017-05-01

A low radiation burden is essential during diagnostic procedures in pediatric patients due to their high tissue sensitivity. Using MR examination instead of the routinely used CT reduces the radiation exposure and the risk of adverse stochastic effects. Our retrospective study evaluated the possibility of using ultrafast single-shot (SSh) sequences and turbo spin echo (TSE) sequences in rapid MR brain imaging in pediatric patients with hydrocephalus and a programmable ventriculoperitoneal drainage system. SSh sequences seem to be suitable for examining pediatric patients due to the speed of using this technique, but significant susceptibility artifacts due to the programmable drainage valve degrade the image quality. Therefore, a rapid MR examination protocol based on TSE sequences, less sensitive to artifacts due to ferromagnetic components, has been developed. Of 61 pediatric patients who were examined using MR and the SSh sequence protocol, a group of 15 patients with hydrocephalus and a programmable drainage system also underwent TSE sequence MR imaging. The susceptibility artifact volume in both rapid MR protocols was evaluated using a semiautomatic volumetry system. A statistically significant decrease in the susceptibility artifact volume has been demonstrated in TSE sequence imaging in comparison with SSh sequences. Using TSE sequences reduced the influence of artifacts from the programmable valve, and the image quality in all cases was rated as excellent. In all patients, rapid MR examinations were performed without any need for intravenous sedation or general anesthesia. Our study results strongly suggest the superiority of the TSE sequence MR protocol compared to the SSh sequence protocol in pediatric patients with a programmable ventriculoperitoneal drainage system due to a significant reduction of susceptibility artifact volume. Both rapid sequence MR protocols provide quick and satisfactory brain imaging with no ionizing radiation and a reduced need

Grooved Glaucoma Drainage Devices That Continuously Deliver Cyclosporine A Decrease Postsurgical Scar Formation in Rabbit Eyes.

PubMed

Dai, Zhaoxing; Yu, Xiaobo; Sun, Jianguo; Sun, Xinghuai

2017-03-01

To study the functional outcomes of filtration surgery by implanting improved glaucoma drainage devices (GDDs) comprising surface grooves and a composite coating of cyclosporine A (CsA) and PLGA in experimental rabbit eyes. Improved GDDs were designed and prepared by modifying normal GDD with surface grooves and a CsA-PLGA composite coating. Normal GDDs, grooved GDDs (G-GDDs), and G-GDDs with a CsA-PLGA composite coating (CsA@G-GDD) were implanted into 18 rabbit eyes (six eyes per group). The intraocular pressure (IOP), bleb survival time, bleb morphology, and anterior chamber reactions were assessed for up to 12 weeks after GDD implantation. The IOPs were compared statistically among the three groups. Bleb morphology was quantified using the Indiana Bleb Appearance Grading Scale. Anterior chamber radiography was performed to check whether the filtrating pathway was blocked, and determine the drainage time and diffusion area of the contrast agent. Hematoxylin and eosin staining and immunohistochemistry were conducted to assess how the GDDs slowed or prevented scar formation. The improved GDDs were successfully prepared and implanted in 18 rabbit eyes without severe surgical complications. Bleb survival time was significantly longer and IOP was significantly lower in the G-GDD and CsA@G-GDD groups compared with the GDD group (all, P < 0.001). Blebs were significantly higher in the CsA@G-GDD group than in the GDD and G-GDD groups (P = 0.003). Anterior chamber radiography revealed more unobstructed filtration channels in the CsA@G-GDD group than in the GDD group (P = 0.032). Postsurgical scar formation was less extensive in the G-GDD and CsA@G-GDD groups than in the GDD group. Compared with the normal GDDs, G-GDDs with a CsA-PLGA coating inhibited postsurgical scar formation and improved the surgical success rate, and might represent an alternative to existing glaucoma filtration devices.

Glaucoma drainage device surgery in children and adults: a comparative study of outcomes and complications.

PubMed

Mandalos, Achilleas; Sung, Velota

2017-05-01

To compare the postoperative outcomes and complications of glaucoma drainage device (GDD) surgery in pediatric (<18 years old) and adult patients. Retrospective, comparative study including all patients who underwent Baervedlt or Molteno device surgery by the same surgeon. Success criteria included postoperative intraocular pressure (IOP) between 6 and 21 mmHg and a 20% reduction from baseline. Fifty-two children (69 eyes) and 130 adults (145 eyes) were included. Mean IOP and number of medications were significantly reduced postoperatively in both groups. Overall failure rate was similar in children and adults. However, GDD failed earlier in adults than in children. Hypotony was the most common complication in both groups in the first 6 months postoperatively. Later on, bleb encapsulation was more frequent in children, while corneal decompensation tended to be more frequent and occurred earlier in adults. Children also had a higher rate of infectious endophthalmitis and required tube repositioning more frequently than adults. GDD surgery presents different postoperative challenges in children and adults, and the surgeon should remain vigilant for complications throughout the postoperative period, especially for signs of endophthalmitis or bleb encapsulation in pediatric patients. On the other hand, adults may be more prone to early corneal decompensation.

Safety valve

DOEpatents

Bergman, Ulf C.

1984-01-01

The safety valve contains a resilient gland to be held between a valve seat and a valve member and is secured to the valve member by a sleeve surrounding the end of the valve member adjacent to the valve seat. The sleeve is movable relative to the valve member through a limited axial distance and a gap exists between said valve member and said sleeve.

Polymeric trileaflet prosthetic heart valves: evolution and path to clinical reality

PubMed Central

Claiborne, Thomas E; Slepian, Marvin J; Hossainy, Syed; Bluestein, Danny

2013-01-01

Present prosthetic heart valves, while hemodynamically effective, remain limited by progressive structural deterioration of tissue valves or the burden of chronic anticoagulation for mechanical valves. An idealized valve prosthesis would eliminate these limitations. Polymeric heart valves (PHVs), fabricated from advanced polymeric materials, offer the potential of durability and hemocompatibility. Unfortunately, the clinical realization of PHVs to date has been hampered by findings of in vivo calcification, degradation and thrombosis. Here, the authors review the evolution of PHVs, evaluate the state of the art of this technology and propose a pathway towards clinical reality. In particular, the authors discuss the development of a novel aortic PHV that may be deployed via transcatheter implantation, as well as its optimization via device thrombogenicity emulation. PMID:23249154

Preliminary engineering study: Quick opening valve MSFC high Reynolds number wind tunnel

NASA Technical Reports Server (NTRS)

1983-01-01

FluiDyne Engineering Corporation has conducted a preliminary engineering study of a quick-opening valve for the MSFC High Reynolds Number Wind Tunnel under NASA Contract NAS8-35056. The subject valve is intended to replace the Mylar diaphragm system as the flow initiation device for the tunnel. Only valves capable of opening within 0.05 sec. and providing a minimum of 11.4 square feet of flow area were considered. Also, the study focused on valves which combined the quick-opening and tight shutoff features in a single unit. A ring sleeve valve concept was chosen for refinement and pricing. Sealing for tight shutoff, ring sleeve closure release and sleeve actuation were considered. The resulting cost estimate includes the valve and requisite modifications to the facility to accommodate the valve as well as the associated design and development work.

Premeasured neochordae loop maker: a new technology in mitral valve repair.

PubMed

Ghavidel, Alireza Alizadeh; Samiei, Niloofar; Javadikasgari, Hoda; Bashirpour, Kamiar

2013-01-01

The exact length of neochordae loops plays the major role in the success of mitral valve repair. The Neochordae Loop Maker is a novel device that models the left ventricular structure in an individual patient. Preoperative transthoracic echocardiography is used to identify the geometry of each papillary muscle and set up the device for the patient. All required neochordae loops are made in the operating room before initiating the cardiopulmonary bypass. In the calibration phase, seven consecutive patients who were candidates for mitral valve replacement underwent transthoracic echocardiography. The device was set up for each patient, and the length of their normal chordae and their respective neochordae was compared by the Bland-Altman analysis. From seven excised mitral valves, 21 chordae were considered normal (gold standard). The length of these gold standards (1.92 ± 0.67 cm) and their respective neochordae (1.93 ± 0.69 cm) showed agreement by the Bland-Altman analysis. The proposed technology showed satisfactory preliminary results in creating the premeasured neochorda loops inasmuch as it reduced the complexity of minimally invasive surgeries.

DEVICE FOR CONTROL OF OXYGEN PARTIAL PRESSURE

DOEpatents

Bradner, H.; Gordon, H.S.

1957-12-24

A device is described that can sense changes in oxygen partial pressure and cause a corresponding mechanical displacement sufficient to actuate meters, valves and similar devices. A piston and cylinder arrangement contains a charge of crystalline metal chelate pellets which have the peculiar property of responding to variations in the oxygen content of the ambient atmosphere by undergoing a change in dimension. A lever system amplifies the relative displacement of the piston in the cylinder, and actuates the controlled valving device. This partial pressure oxygen sensing device is useful in controlled chemical reactions or in respiratory devices such as the oxygen demand meters for high altitude aircraft.

First-in-man use of a novel embolic protection device for patients undergoing transcatheter aortic valve implantation.

PubMed

Naber, Christoph K; Ghanem, Alexander; Abizaid, Alexander A; Wolf, Alexander; Sinning, Jan-Malte; Werner, Nikos; Nickenig, Georg; Schmitz, Thomas; Grube, Eberhard

2012-05-15

We describe the first-in-human experience with a novel cerebral embolic protection device used during transcatheter aortic valve implantation (TAVI). One current challenge of TAVI is the reduction of procedural stroke. Procedural mobilisation of debris is a known source of cerebral embolisation. Mechanical protection by transient filtration of cerebral blood flow might reduce the embolic burden during TAVI. We aimed to evaluate the feasibility and safety of the Claret CE Pro™ cerebral protection device in patients undergoing TAVI. Patients scheduled for TAVI were prospectively enrolled at three centres. The Claret CE Pro™ (Claret Medical, Inc. Santa Rosa, CA, USA) cerebral protection device was placed via the right radial/brachial artery prior to TAVI and was removed after the procedure. The primary endpoint was technical success rate. Secondary endpoints encompassed procedural and 30-day stroke rates, as well as device-related complications. Deployment of the Claret CE Pro™ cerebral protection device was intended for use in 40 patients, 35 devices were implanted into the aortic arch. Technical success rate with delivery of the proximal and distal filter was 60% for the first generation device and 87% for the second-generation device. Delivery times for the first-generation device were 12.4±12.1 minutes and 4.4 ± 2.5 minutes for the second-generation device (p<0.05). The quantity of contrast used related to the Claret CE Pro System was 19.6 ± 3.8 ml. Captured debris was documented in at least 19 of 35 implanted devices (54.3%). No procedural transient ischaemic attacks, minor strokes or major strokes occurred. Thirty-day follow-up showed one minor stroke occurring 30 days after the procedure, and two major strokes both occurring well after the patient had completed TAVI. The use of the Claret CE Pro™ system is feasible and safe. Capture of debris in more than half of the patients provides evidence for the potential to reduce the procedural cerebral

Fabrication of micro metallic valve and pump

NASA Astrophysics Data System (ADS)

Yang, Ming; Kabasawa, Yasunari; Ito, Kuniyoshi

2010-03-01

Fabrication of micro devices by using micro metal forming was proposed by the authors. We developed a desktop servo-press machine with precise tooling system. Precise press forming processes including micro forging and micro joining has been carried out in a progressive die. In this study, micro metallic valve and pump were fabricated by using the precise press forming. The components are made of sheet metals, and assembled in to a unit in the progressive die. A micro check-valve with a diameter of 3mm and a length of 3.2mm was fabricated, and the property of flow resistance was evaluated. The results show that the check valve has high property of leakage proof. Since the valve is a unit parts with dimensions of several millimeters, it has advantage to be adapted to various pump design. Here, two kinds of micro pumps with the check-valves were fabricated. One is diaphragm pump actuated by vibration of the diaphragm, and another is tube-shaped pump actuated by resonation. The flow quantities of the pumps were evaluated and the results show that both of the pumps have high pumping performance.

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.

Drainage of malignant ascites: patient selection and perspectives

PubMed Central

Stukan, Maciej

2017-01-01

Malignant ascites (MA) is a sign of advanced cancer and poor prognosis. MA can result in impairment in quality of life (QOL) and significant symptoms. As a supportive treatment, ascites can be drained by paracentesis (PC), percutaneously implanted catheters (tunneled, untunneled, central venous catheters), or peritoneal ports, or peritoneovenous shunts. The aim of this study was to evaluate the effectiveness, safety, and patient-reported outcomes (PRO) of different drainage methods for the management of MA. A systematic review of the literature was performed, and 32 original articles met the inclusion criteria. Patients selected for permanent drain insertion demonstrated symptoms related to MA and had undergone repeated PC. The primary focus of the reviewed articles was procedural safety issues. The rate of technical success of drainage device installation was 100%. Most patients experienced improvements in symptom control after ascites drainage. When analyzed together, 19.7% (255/1297) of patients experienced any complication and 6.2% (81/1297) experienced serious adverse events during MA drainage. Complications were reported for every drainage method; however, the least occurred after PC or central venous catheter, while the most serious occurred after peritoneovenous shunts. Adverse events were as follows: catheter obstruction: 4.4%, infection: 4.1%, leakage: 3.5%, catheter dislodgment: 2.3%, hypotension: 0.6%, injuries during device insertion: 0.6%, renal impairment: 0.5%, electrolyte imbalance: 0.2%, other: 3.6%. PRO and QOL endpoints were available for 12 studies. When PRO were measured using an interview, a significant improvement in symptom control and QOL was reported in almost all patients. Once standardized questionnaires were used, improvements in symptomatic scores and role functioning were observed. Deterioration was observed in cognitive and emotional subscales. MA drainage is a safe and effective method to control symptoms associated with ascites

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of...

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.

Ahmed glaucoma valve implant: surgical technique and complications.

PubMed

Riva, Ivano; Roberti, Gloria; Oddone, Francesco; Konstas, Anastasios Gp; Quaranta, Luciano

2017-01-01

Implantation of Ahmed glaucoma valve is an effective surgical technique to reduce intraocular pressure in patients affected with glaucoma. While in the past, the use of this device was reserved to glaucoma refractory to multiple filtration surgical procedures, up-to-date mounting experience has encouraged its use also as a primary surgery for selected cases. Implantation of Ahmed glaucoma valve can be challenging for the surgeon, especially in patients who already underwent previous multiple surgeries. Several tips have to be acquired by the surgeon, and a long learning curve is always needed. Although the valve mechanism embedded in the Ahmed glaucoma valve decreases the risk of postoperative hypotony-related complications, it does not avoid the need of a careful follow-up. Complications related to this type of surgery include early and late postoperative hypotony, excessive capsule fibrosis around the plate, erosion of the tube or plate edge, and very rarely infection. The aim of this review is to describe surgical technique for Ahmed glaucoma valve implantation and to report related complications.

Ahmed glaucoma valve implant: surgical technique and complications

PubMed Central

Riva, Ivano; Roberti, Gloria; Oddone, Francesco; Konstas, Anastasios GP; Quaranta, Luciano

2017-01-01

Implantation of Ahmed glaucoma valve is an effective surgical technique to reduce intraocular pressure in patients affected with glaucoma. While in the past, the use of this device was reserved to glaucoma refractory to multiple filtration surgical procedures, up-to-date mounting experience has encouraged its use also as a primary surgery for selected cases. Implantation of Ahmed glaucoma valve can be challenging for the surgeon, especially in patients who already underwent previous multiple surgeries. Several tips have to be acquired by the surgeon, and a long learning curve is always needed. Although the valve mechanism embedded in the Ahmed glaucoma valve decreases the risk of postoperative hypotony-related complications, it does not avoid the need of a careful follow-up. Complications related to this type of surgery include early and late postoperative hypotony, excessive capsule fibrosis around the plate, erosion of the tube or plate edge, and very rarely infection. The aim of this review is to describe surgical technique for Ahmed glaucoma valve implantation and to report related complications. PMID:28255226

A Quantitative Study of Simulated Bicuspid Aortic Valves

NASA Astrophysics Data System (ADS)

Szeto, Kai; Nguyen, Tran; Rodriguez, Javier; Pastuszko, Peter; Nigam, Vishal; Lasheras, Juan

2010-11-01

Previous studies have shown that congentially bicuspid aortic valves develop degenerative diseases earlier than the standard trileaflet, but the causes are not well understood. It has been hypothesized that the asymmetrical flow patterns and turbulence found in the bileaflet valves together with abnormally high levels of strain may result in an early thickening and eventually calcification and stenosis. Central to this hypothesis is the need for a precise quantification of the differences in the strain rate levels between bileaflets and trileaflet valves. We present here some in-vitro dynamic measurements of the spatial variation of the strain rate in pig aortic vales conducted in a left ventricular heart flow simulator device. We measure the strain rate of each leaflet during the whole cardiac cycle using phase-locked stereoscopic three-dimensional image surface reconstruction techniques. The bicuspid case is simulated by surgically stitching two of the leaflets in a normal 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.

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

Immediate Outcomes of Aortic Valve Replacement with Sutureless versus Stentless Bioprosthesis.

PubMed

Ihsan Parlar, Ali; Onur Hanedan, Muhammet; Mataraci, Ilker; Ali Yuruk, Mehmet; Sayar, Ufuk; Kemal Arslan, Ali; Ozer, Tanil

2016-01-01

Aortic valve replacement (AVR) with a sutureless valve is an innovative therapy in high-risk elderly patients. The study aim was to compare the early results of AVR using sutureless aortic valves or stentless aortic bioprostheses. A retrospective analysis was conducted of 55 patients who underwent AVR with either a sutureless valve (Perceval S; n = 24 or Edwards Intuity; n = 9) or a stentless valve (Sorin Freedom SOLO™; n = 22). Baseline patient characteristics were similar in both groups, except for NYHA class. Concomitant procedures were performed in 17 patients (51.5%) of the sutureless group and in nine patients (40.9%) of the stentless group (p = 0.44). The aortic cross-clamp time was 55 ± 23 min in the sutureless group and 102 ± 36 min in the stentless group (p <0.0001), while the postoperative peak aortic gradient was 19.5 ± 5.0 mmHg and 29.3 ± 15.4 mmHg for the sutureless group and stentless group, respectively (p = 0.037). The postoperative mean gradient was 9.3 ± 3.4 mmHg for the sutureless group and 15.1 ± 10.5 mmHg for the stentless group (p = 0.06). Blood product transfusion was required less frequently by the sutureless group, but drainage and bleeding was similar in both groups. The intensive care unit and hospital stays were significantly shorter in favor of the sutureless group. One sutureless patient (3.0%) and two stentless patients (9.1%) died in hospital (p = 0.557). Early results of the present study suggested that surgical AVR with a sutureless valve is associated with a good hemodynamic performance and an improved early outcome.

Modular microfluidic valve structures based on reversible thermoresponsive ionogel actuators.

PubMed

Benito-Lopez, Fernando; Antoñana-Díez, Marta; Curto, Vincenzo F; Diamond, Dermot; Castro-López, Vanessa

2014-09-21

This paper reports for the first time the use of a cross-linked poly(N-isopropylacrylamide) ionogel encapsulating the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulphate as a thermoresponsive and modular microfluidic valve. The ionogel presents superior actuation behaviour to its equivalent hydrogel. Ionogel swelling and shrinking mechanisms and kinetics are investigated as well as the performance of the ionogel when integrated as a valve in a microfluidic device. The modular microfluidic valve demonstrates fully a reversible on-off behaviour without failure for up to eight actuation cycles and a pressure resistance of 1100 mbar.

Performance Evaluation of a High Bandwidth Liquid Fuel Modulation Valve for Active Combustion Control

NASA Technical Reports Server (NTRS)

Saus, Joseph R.; DeLaat, John C.; Chang, Clarence T.; Vrnak, Daniel R.

2012-01-01

At the NASA Glenn Research Center, a characterization rig was designed and constructed for the purpose of evaluating high bandwidth liquid fuel modulation devices to determine their suitability for active combustion control research. Incorporated into the rig s design are features that approximate conditions similar to those that would be encountered by a candidate device if it were installed on an actual combustion research rig. The characterized dynamic performance measures obtained through testing in the rig are planned to be accurate indicators of expected performance in an actual combustion testing environment. To evaluate how well the characterization rig predicts fuel modulator dynamic performance, characterization rig data was compared with performance data for a fuel modulator candidate when the candidate was in operation during combustion testing. Specifically, the nominal and off-nominal performance data for a magnetostrictive-actuated proportional fuel modulation valve is described. Valve performance data were collected with the characterization rig configured to emulate two different combustion rig fuel feed systems. Fuel mass flows and pressures, fuel feed line lengths, and fuel injector orifice size was approximated in the characterization rig. Valve performance data were also collected with the valve modulating the fuel into the two combustor rigs. Comparison of the predicted and actual valve performance data show that when the valve is operated near its design condition the characterization rig can appropriately predict the installed performance of the valve. Improvements to the characterization rig and accompanying modeling activities are underway to more accurately predict performance, especially for the devices under development to modulate fuel into the much smaller fuel injectors anticipated in future lean-burning low-emissions aircraft engine combustors.

Assessment of Filtration Bleb and Endplate Positioning Using Magnetic Resonance Imaging in Eyes Implanted with Long-Tube Glaucoma Drainage Devices.

PubMed

Sano, Ichiya; Tanito, Masaki; Uchida, Koji; Katsube, Takashi; Kitagaki, Hajime; Ohira, Akihiro

2015-01-01

To evaluate ocular fluid filtration and endplate positioning in glaucomatous eyes with long-tube glaucoma drainage devices (GDDs) using magnetic resonance imaging (MRI) and the effects of various factors on postoperative intraocular pressure (IOP). This observational case series included 27 consecutive glaucomatous eyes (18 men, 7 women; mean age ± standard error, 63.0±2.0 years) who underwent GDD implantation (n = 8 Ahmed Glaucoma Valves [AGV] and n = 19 Baerveldt Glaucoma Implants [BGI]). Tubes were inserted into the pars plana in 23 eyes and anterior chamber in 4 eyes. Six months postoperatively, high-resolution orbital images were obtained using 3-Tesla MRI with head-array coils, and the filtering bleb volume, bleb height, and distances between the anterior endplate edge and corneal center or limbus or between the endplate and orbital wall were measured. In MR images obtained by three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequences, the shunt endplate was identified as low-intensity signal, and the filtering bleb was identified as high-intensity signals above and below the endplate in all eyes. The 6-month-postoperative IOP level was correlated negatively with bleb volume (r = -0.4510, P = 0.0182) and bleb height (r = -0.3954, P = 0.0412). The postoperative IOP was significantly (P = 0.0026) lower in BGI-implanted eyes (12.2±0.7 mmHg) than AGV-implanted eyes (16.7±1.2 mmHg); bleb volume was significantly (P = 0.0093) larger in BGI-implanted eyes (478.8±84.2 mm3) than AGV-implanted eyes (161.1±52.3 mm3). Other parameters did not differ. The presence of intraorbital/periocular accumulation of ocular fluid affects postoperative IOP levels in eyes implanted with long-tube GDDs. Larger filtering blebs after BGI than AGI implantations explain lower postoperative IOP levels achieved with BGI than AGV. The findings will contribute to better understanding of IOP reducing mechanism of long-tube GDDs.

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.

Design of a Cyclic Pressure Bioreactor for the Ex Vivo Study of Aortic Heart Valves

PubMed Central

Schipke, Kimberly J.; Filip To, S. D.; Warnock, James N.

2011-01-01

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic valve leaflets are composed of interstitial cells suspended within an extracellular matrix (ECM) and are lined with an endothelial cell monolayer. The valve withstands a harsh, dynamic environment and is constantly exposed to shear, flexion, tension, and compression. Research has shown calcific lesions in diseased valves occur in areas of high mechanical stress as a result of endothelial disruption or interstitial matrix damage1-3. Hence, it is not surprising that epidemiological studies have shown high blood pressure to be a leading risk factor in the onset of aortic valve disease4. The only treatment option currently available for valve disease is surgical replacement of the diseased valve with a bioprosthetic or mechanical valve5. Improved understanding of valve biology in response to physical stresses would help elucidate the mechanisms of valve pathogenesis. In turn, this could help in the development of non-invasive therapies such as pharmaceutical intervention or prevention. Several bioreactors have been previously developed to study the mechanobiology of native or engineered heart valves6-9. Pulsatile bioreactors have also been developed to study a range of tissues including cartilage10, bone11 and bladder12. The aim of this work was to develop a cyclic pressure system that could be used to elucidate the biological response of aortic valve leaflets to increased pressure loads. The system consisted of an acrylic chamber in which to place samples and produce cyclic pressure, viton diaphragm solenoid valves to control the timing of the pressure cycle, and a computer to control electrical devices. The pressure was monitored using a pressure transducer, and the signal was conditioned using a load cell conditioner. A LabVIEW program regulated the pressure using an analog device to pump compressed air into the

Design of a cyclic pressure bioreactor for the ex vivo study of aortic heart valves.

PubMed

Schipke, Kimberly J; To, S D Filip; Warnock, James N

2011-08-23

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic valve leaflets are composed of interstitial cells suspended within an extracellular matrix (ECM) and are lined with an endothelial cell monolayer. The valve withstands a harsh, dynamic environment and is constantly exposed to shear, flexion, tension, and compression. Research has shown calcific lesions in diseased valves occur in areas of high mechanical stress as a result of endothelial disruption or interstitial matrix damage(1-3). Hence, it is not surprising that epidemiological studies have shown high blood pressure to be a leading risk factor in the onset of aortic valve disease(4). The only treatment option currently available for valve disease is surgical replacement of the diseased valve with a bioprosthetic or mechanical valve(5). Improved understanding of valve biology in response to physical stresses would help elucidate the mechanisms of valve pathogenesis. In turn, this could help in the development of non-invasive therapies such as pharmaceutical intervention or prevention. Several bioreactors have been previously developed to study the mechanobiology of native or engineered heart valves(6-9). Pulsatile bioreactors have also been developed to study a range of tissues including cartilage(10), bone(11) and bladder(12). The aim of this work was to develop a cyclic pressure system that could be used to elucidate the biological response of aortic valve leaflets to increased pressure loads. The system consisted of an acrylic chamber in which to place samples and produce cyclic pressure, viton diaphragm solenoid valves to control the timing of the pressure cycle, and a computer to control electrical devices. The pressure was monitored using a pressure transducer, and the signal was conditioned using a load cell conditioner. A LabVIEW program regulated the pressure using an analog device to pump compressed

Microfluidic valve with cored glass microneedle for microinjection.

PubMed

Lee, Sanghoon; Jeong, Wonje; Beebe, David J

2003-08-01

In this paper, a new microinjection device was constructed by fusing a glass microneedle and a PDMS-based microvalve. The microneedle was fabricated via traditional micropipette pulling. The PDMS-based microvalve regulates the fluid flow in the microchannel and microneedle. The 'ON/OFF' operation of the valve was controlled by manually supplied pneumatic pressure. The valve membrane utilized a two level geometry to improve control at low flow rates. The relation between pressure and flow was measured and the results showed that very small volumes of fluid (>1 nl) could be controlled. The valve operation was investigated by monitoring the tip of the needle and pneumatic pressure simultaneously and it demonstrated very stable 'ON/OFF' operation to the pressure change.

Water system microbial check valve development

NASA Technical Reports Server (NTRS)

Colombo, G. V.; Greenley, D. R.; Putnam, D. F.

1978-01-01

Development work on a device for the Space Shuttle that will prevent the transfer of viable microorganisms within water systems is described. The device serves as a check valve in that it prevents the transfer or cross-contamination of microorganisms from a nonpotable system into a potable water system when these systems are interconnected. In this regard, the function of the device is similar to that of the air gap found in conventional one gravity systems. The device is essentially a bed of resin material impregnated with iodine. Basic design data for a variety of flow and temperature conditions are presented, together with results of challenging the beds with suspensions of seven microorganisms including aerobes, anaerobes, and spore formers.

Pressure Relief Devices

NASA Astrophysics Data System (ADS)

Manha, William D.

2010-09-01

Pressure relief devices are used in pressure systems and on pressure vessels to prevent catastrophic rupture or explosion from excessive pressure. Pressure systems and pressure vessels have manufacturers maximum rated operating pressures or maximum design pressures(MDP) for which there are relatively high safety factors and minimum risk of rupture or explosion. Pressure systems and pressure vessels that have a potential to exceed the MDP by being connected to another higher pressure source, a compressor, or heat to water(boiler) are required to have over-pressure protecting devices. Such devices can be relief valves and/or burst discs to safely relieve potentially excessive pressure and prevent unacceptable ruptures and explosions which result in fail-safe pressure systems and pressure vessels. Common aerospace relief valve and burst disc requirements and standards will be presented. This will include the NASA PSRP Interpretation Letter TA-88-074 Fault Tolerance of Systems Using Specially Certified Burst Disks that dictates burst disc requirements for payloads on Shuttle. Two recent undesirable manned space payloads pressure relief devices and practices will be discussed, as well as why these practices should not be continued. One example for discussion is the use of three burst discs that have been placed in series to comply with safety requirements of three controls to prevent a catastrophic hazard of the over-pressurization and rupture of pressure system and/or vessels. The cavities between the burst discs are evacuated and are the reference pressures for activating the two upstream burst discs. If the upstream burst disc leaks into the reference cavity, the reference pressure increases and it can increase the burst disc activating pressure and potentially result in the burst disc assembly being ineffective for over pressure protection. The three burst discs-in-series assembly was found acceptable because the burst discs are designed for minimum risk(DFMR) of

Multi-depth valved microfluidics for biofilm segmentation

NASA Astrophysics Data System (ADS)

Meyer, M. T.; Subramanian, S.; Kim, Y. W.; Ben-Yoav, H.; Gnerlich, M.; Gerasopoulos, K.; Bentley, W. E.; Ghodssi, R.

2015-09-01

Bacterial biofilms present a societal challenge, as they occur in the majority of infections but are highly resistant to both immune mechanisms and traditional antibiotics. In the pursuit of better understanding biofilm biology for developing new treatments, there is a need for streamlined, controlled platforms for biofilm growth and evaluation. We leverage advantages of microfluidics to develop a system in which biofilms are formed and sectioned, allowing parallel assays on multiple sections of one biofilm. A microfluidic testbed with multiple depth profiles was developed to accommodate biofilm growth and sectioning by hydraulically actuated valves. In realization of the platform, a novel fabrication technique was developed for creating multi-depth microfluidic molds using sequentially patterned photoresist separated and passivated by conformal coatings using atomic layer deposition. Biofilm thickness variation within three separately tested devices was less than 13% of the average thickness in each device, while variation between devices was 23% of the average thickness. In a demonstration of parallel experiments performed on one biofilm within one device, integrated valves were used to trisect the uniform biofilms with one section maintained as a control, and two sections exposed to different concentrations of sodium dodecyl sulfate. The technology presented here for multi-depth microchannel fabrication can be used to create a host of microfluidic devices with diverse architectures. While this work focuses on one application of such a device in biofilm sectioning for parallel experimentation, the tailored architectures enabled by the fabrication technology can be used to create devices that provide new biological information.

Electrical isolation and characteristics of permanent magnet-actuated valves for PDMS microfluidics.

PubMed

Chen, Chang-Yu; Chen, Chang-Hung; Tu, Ting-Yuan; Lin, Cheng-Ming; Wo, Andrew M

2011-02-21

This paper presents a magnetically driven valve via a permanent magnet pressing a spacer against deformable polydimethylsiloxane (PDMS) to fully close a microchannel. Its ability for electrical isolation, time response, and resistance to backpressure are interrogated. Simulation of the valve closing process was commenced along with experimental verification. Effects of PDMS thickness, and dimension and aspect ratio of microchannels were characterized. Up to 10 GΩ electrical isolation was demonstrated, as well as 50-70 ms valve response and ∼200 kPa resistible pressure. On-demand actuation for arbitrary flow patterns further quantifies its utility. With advantages of simple fabrication, flexible valving location, and no external power requirement, the on/off valve could be leveraged for proof-of-concept microfluidic devices and other applications.

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

PubMed Central

2016-01-01

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

The optimization of design parameters for surge relief valve for pipeline systems

NASA Astrophysics Data System (ADS)

Kim, Hyunjun; Hur, Jisung; Kim, Sanghyun

2017-06-01

Surge is an abnormal pressure which induced by rapid changes of flow rate in pipeline systems. In order to protect pipeline system from the surge pressure, various hydraulic devices have been developed. Surge-relief valve(SRV) is one of the widely applied devices to control surge due to its feasibility in application, efficiency and cost-effectiveness. SRV is designed to automatically open under abnormal pressure and discharge the flow and makes pressure of the system drop to the allowable level. The performance of the SRV is influenced by hydraulics. According to previous studies, there are several affecting factors which determine performance of the PRV such as design parameters (e.g. size of the valve), system parameters (e.g. number of the valves and location of the valve), and operation parameters (e.g. set point and operation time). Therefore, the systematic consideration for factors affecting performance of SRV is required for the proper installation of SRV in the system. In this study, methodology for finding optimum parameters of the SRV is explored through the integration of Genetic Algorithm(GA) into surge analysis.

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.

The combination of a programmable valve and a subclavicular anti-gravity device in hydrocephalus patients at high risk for hygromas.

PubMed

Zachenhofer, Iris; Donat, Markus; Roessler, Karl

2012-04-01

In order to avoid occurrence of post-operative hygromas in specific hydrocephalus patients being at high risk of overdrainage, a combination of programmable valve and anti-gravity device is widely recommended. We analyzed our series of hydrocephalus patients implanted with such a shunt configuration focusing on complications in relation to over-/underdrainage and neurological outcome. In 28 hydrocephalic patients (14 women and 14 men; mean age 65 years, range from 14 to 82 years; 11 normal pressure, 7 post-traumatic, and 4 post-hemorrhagic hydrocephalus), a Codman Medos programmable valve combined with a Miethke shunt assistant (SA) was implanted at the Department of Neurosurgery of the Academic Teaching Hospital Feldkirch. Implantation was performed simultaneously in 20 patients during the primary procedure: in five patients, SA was placed during revision surgery, and in three patients, the patent system was completed by additional implantation of an SA. Subdural hematoma occurred in one out of 20 patients with SA implantation during primary procedure and in two out of eight patients with SA implantation as secondary procedure, respectively. Shunt occlusion occurred in one patient out of the patients with SA implantation during primary procedure, but was seen in three patients with pre-existing shunt without SA. Shunt infection occurred in one case. Our results suggest the combination of an adjustable valve and SA as an effective treatment for a specific group of hydrocephalus patients being at high risk for overdrainage.

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.

Elective removal of convexo-concave Björk-Shiley valves.

PubMed

Rajesh, P B; Smith, G H; Lawford, P V; Black, M M

1994-08-01

Replacement has been an accepted method for treating advanced cardiac valvular disease for more than 25 years. However, the perfect prosthesis has yet to be developed, judging by the number of devices available. A prosthesis that initially appears promising may cause problems in due course, and indeed some devices have been modified or withdrawn from clinical use. A notable example of a prosthetic valve that has give problems is the Björk-Shiley convexo-concave prosthesis, some models of which have undergone mechanical failure due to strut fracture. We report the elective removal of such a valve and the subsequent examination of the prosthesis. The results of this examination suggest that a policy of elective removal is justified.

Magneto-capillary valve for integrated purification and enrichment of nucleic acids and proteins.

PubMed

den Dulk, Remco C; Schmidt, Kristiane A; Sabatté, Gwénola; Liébana, Susana; Prins, Menno W J

2013-01-07

We describe the magneto-capillary valve (MCV) technology, a flexible approach for integrated biological sample preparation within the concept of stationary microfluidics. Rather than moving liquids in a microfluidic device, discrete units of liquid are present at fixed positions in the device and magnetic particles are actuated between the fluids. The MCV concept is characterized by the use of two planar surfaces at a capillary mutual distance, with specific features to confine the fluids by capillary forces, and the use of a gas or a phase-change material separating the stationary aqueous liquids. We have studied the physics of magneto-capillary valving by quantifying the magnetic force as a function of time and position, which reveals the balance of magnetic, capillary and frictional forces in the system. By purification experiments with a fluorescent tracer we have measured the amount of co-transported liquid, which is a key parameter for efficient purification. To demonstrate the versatility of the technology, several MCV device architectures were tested in a series of biological assays, showing the purification and enrichment of nucleic acids and proteins. Target recovery comparable to non-miniaturized commercial kits was observed for the extraction of DNA from human cells in buffer, using a device architecture with patterned air valves. Experiments using an enrichment module and patterned air valves demonstrate a 40-fold effective enrichment of DNA in buffer. DNA was also successfully purified from blood plasma using paraffin phase-change valves. Finally, the enrichment of a protein biomarker (prostate-specific antigen) using geometrical air valves resulted in a 7-fold increase of detection signal. The MCV technology is versatile, offers extensive freedom for the design of fully integrated systems, and is expected to be manufacturable in a cost-effective way. We conclude that the MCV technology can become an important enabling technology for point

Needle aspiration versus intercostal tube drainage for pneumothorax in the newborn.

PubMed

Bruschettini, Matteo; Romantsik, Olga; Ramenghi, Luca Antonio; Zappettini, Simona; O'Donnell, Colm P F; Calevo, Maria Grazia

2016-01-11

Pneumothorax occurs more frequently in the neonatal period than at any other time of life and is associated with increased mortality and morbidity. It may be treated with either needle aspiration or insertion of a chest tube. The former consists of aspiration of air with a syringe through a needle or an angiocatheter, usually through the second or third intercostal space in the midclavicular line. The chest tube is usually placed in the anterior pleural space passing through the sixth intercostal space into the pleural opening, turned anteriorly and directed to the location of the pneumothorax, and then connected to a Heimlich valve or an underwater seal with continuous suction. To compare the efficacy and safety of needle aspiration and intercostal tube drainage in the management of neonatal pneumothorax. We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 11), MEDLINE via PubMed (1966 to 30 November 2015), EMBASE (1980 to 30 November 2015), and CINAHL (1982 to 30 November 2015). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised controlled trials, quasi-randomised controlled trials and cluster trials comparing needle aspiration (either with the needle or angiocatheter left in situ or removed immediately after aspiration) to intercostal tube drainage in newborn infants with pneumothorax. For each of the included trial, two authors independently extracted data (e.g. number of participants, birth weight, gestational age, kind of needle and chest tube, choice of intercostal space, pressure and device for drainage) and assessed the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). The primary outcomes considered in this review are mortality during the neonatal period and during hospitalisation. One

Three-dimentional simulation of flow-induced platelet activation in artificial heart valves

NASA Astrophysics Data System (ADS)

Hedayat, Mohammadali; Asgharzadeh, Hafez; Borazjani, Iman

2015-11-01

Since the advent of heart valve, several valve types such as mechanical and bio-prosthetic valves have been designed. Mechanical Heart Valves (MHV) are durable but suffer from thromboembolic complications that caused by shear-induced platelet activation near the valve region. Bio-prosthetic Heart Valves (BHV) are known for better hemodynamics. However, they usually have a short average life time. Realistic simulations of heart valves in combination with platelet activation models can lead to a better understanding of the potential risk of thrombus formation in such devices. In this study, an Eulerian approach is developed to calculate the platelet activation in three-dimensional simulations of flow through MHV and BHV using a parallel overset-curvilinear immersed boundary technique. A curvilinear body-fitted grid is used for the flow simulation through the anatomic aorta, while the sharp-interface immersed boundary method is used for simulation of the Left Ventricle (LV) with prescribed motion. In addition, dynamics of valves were calculated numerically using under-relaxed strong-coupling algorithm. Finally, the platelet activation results for BMV and MHV are compared with each other.

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.

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.

Successful continuous-flow left ventricular assist device implantation with adjuvant tricuspid valve repair for advanced heart failure.

PubMed

Lee, Chih-Hsien; Wei, Jeng

The prevalence of end-stage heart failure (HF) is on the increase, however, the availability of donor hearts remains limited. Left ventricular assist devices (LVADs) are increasingly being used for treating patients with end-stage HF. LVADs are not only used as a bridge to transplantation but also as a destination therapy. HeartMate II, a new-generation, continuous-flow LVAD (cf-LVAD), is currently an established treatment option for patients with HF. Technological progress and increasing implantation of cf-LVADs have significantly improved survival in patients with end-stage HF. Here we report a case of a patient with end-stage HF who was successfully supported using cf-LVAD implantation with adjuvant tricuspid valve repair in a general district hospital.

A remotely operated drug delivery system with an electrolytic pump and a thermo-responsive valve

PubMed Central

Yi, Ying; Zaher, Amir; Yassine, Omar; Kosel, Jurgen; Foulds, Ian G.

2015-01-01

Implantable drug delivery devices are becoming attractive due to their abilities of targeted and controlled dose release. Currently, two important issues are functional lifetime and non-controlled drug diffusion. In this work, we present a drug delivery device combining an electrolytic pump and a thermo-responsive valve, which are both remotely controlled by an electromagnetic field (40.5 mT and 450 kHz). Our proposed device exhibits a novel operation mechanism for long-term therapeutic treatments using a solid drug in reservoir approach. Our device also prevents undesired drug liquid diffusions. When the electromagnetic field is on, the electrolysis-induced bubble drives the drug liquid towards the Poly (N-Isopropylacrylamide) (PNIPAM) valve that consists of PNIPAM and iron micro-particles. The heat generated by the iron micro-particles causes the PNIPAM to shrink, resulting in an open valve. When the electromagnetic field is turned off, the PNIPAM starts to swell. In the meantime, the bubbles are catalytically recombined into water, reducing the pressure inside the pumping chamber, which leads to the refilling of the fresh liquid from outside the device. A catalytic reformer is included, allowing more liquid refilling during the limited valve's closing time. The amount of body liquid that refills the drug reservoir can further dissolve the solid drug, forming a reproducible drug solution for the next dose. By repeatedly turning on and off the electromagnetic field, the drug dose can be cyclically released, and the exit port of the device is effectively controlled. PMID:26339328

Electronic spin transport in gate-tunable black phosphorus spin valves

NASA Astrophysics Data System (ADS)

Liu, Jiawei; Avsar, Ahmet; Tan, Jun You; Oezyilmaz, Barbaros

High charge mobility, the electric field effect and small spin-orbit coupling make semiconducting black phosphorus (BP) a promising material for spintronics device applications requiring long spin distance spin communication with all rectification and amplification actions. Towards this, we study the all electrical spin injection, transport and detection under non-local spin valve geometry in fully encapsulated ultra-thin BP devices. We observe spin relaxation times as high as 4 ns, with spin relaxation lengths exceeding 6 μm. These values are an order of magnitude higher than what have been measured in typical graphene spin valve devices. Moreover, the spin transport depends strongly on charge carrier concentration and can be manipulated in a spin transistor-like manner by controlling electric field. This behaviour persists even at room temperature. Finally, we will show that similar to its electrical and optical properties, spin transport property is also strongly anisotropic.

Quantification and comparison of the mechanical properties of four human cardiac valves.

PubMed

Pham, Thuy; Sulejmani, Fatiesa; Shin, Erica; Wang, Di; Sun, Wei

2017-05-01

Although having the same ability to permit unidirectional flow within the heart, the four main valves-the mitral valve (MV), aortic (AV), tricuspid (TV) and pulmonary (PV) valves-experience different loading conditions; thus, they exhibit different structural integrity from one another. Most research on heart valve mechanics have been conducted mainly on MV and AV or an individual valve, but none quantify and compare the mechanical and structural properties among the four valves from the same aged patient population whose death was unrelated to cardiovascular disease. A total of 114 valve leaflet samples were excised from 12 human cadavers whose death was unrelated to cardiovascular disease (70.1±3.7years old). Tissue mechanical and structural properties were characterized by planar biaxial mechanical testing and histological methods. The experimental data were then fitted with a Fung-type constitutive model. The four valves differed substantially in thickness, degree of anisotropy, and stiffness. The leaflets of the left heart (the AV leaflets and the anterior mitral leaflets, AML) were significantly stiffer and less compliant than their counterparts in the right heart. TV leaflets were the most extensible and isotropic, while AML and AV leaflets were the least extensible and the most anisotropic. Age plays a significant role in the reduction of leaflet stiffness and extensibility with nearly straightened collagen fibers observed in the leaflet samples from elderly groups (65years and older). Results from 114 human leaflet samples not only provided a baseline quantification of the mechanical properties of aged human cardiac valves, but also offered a better understanding of the age-dependent differences among the four valves. It is hoped that the experimental data collected and the associated constitutive models in this study can facilitate future studies of valve diseases, treatments and the development of interventional devices. Most research on heart valve

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

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

Toma, Milan; Jensen, Morten Ø.; Einstein, Daniel R.

2015-07-17

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

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

PubMed

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

2016-04-01

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

Tricuspid Valve Dysfunction Following Pacemaker or Cardioverter-Defibrillator Implantation.

PubMed

Chang, James D; Manning, Warren J; Ebrille, Elisa; Zimetbaum, Peter J

2017-05-09

The potential for cardiac implantable electronic device leads to interfere with tricuspid valve (TV) function has gained increasing recognition as having hemodynamic and clinical consequences associated with incremental morbidity and death. The diagnosis and treatment of lead-related (as distinct from functional) tricuspid regurgitation pose unique challenges. Because of pitfalls in routine diagnostic imaging, a high level of clinical suspicion must be maintained to avoid overlooking the possibility that worsening heart failure is a consequence of mechanical interference with TV leaflet mobility or coaptation and is amenable to lead extraction or valve repair or replacement. The future of cardiac implantable electronic devices includes pacing and perhaps defibrillation without a lead traversing the TV. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Foot pedal operated fluid type exercising device

NASA Technical Reports Server (NTRS)

Crum, G. W.; Sauter, R. J. (Inventor)

1973-01-01

A foot pedal operated exercising device is reported that contains a dynamometer formed of a pair of cylinders each containing a piston. The pistons are linked to each other. The upper portions of the two cylinders are joined together by a common opening to provide a common fluid reservoir and each piston is provided with a one way check valve to maintain an adequate supply of working fluid. Fluid from the driven cylinder is transmitted to the other cylinder through separate constant force spring biased valves each valve takes the predominant portion of the pressure drop thereby providing a constant force hydraulic dynamometer. A device is provided to determine the amount of movement of piston travel.

Self-actuated device

DOEpatents

Hecht, Samuel L.

1984-01-01

A self-actuated device, of particular use as a valve or an orifice for nuclear reactor fuel and blanket assemblies, in which a gas produced by a neutron induced nuclear reaction gradually accumulates as a function of neutron fluence. The gas pressure increase occasioned by such accumulation of gas is used to actuate the device.

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

Towards real-time cardiovascular magnetic resonance guided transarterial CoreValve implantation: in vivo evaluation in swine

PubMed Central

2012-01-01

Background Real-time cardiovascular magnetic resonance (rtCMR) is considered attractive for guiding TAVI. Owing to an unlimited scan plane orientation and an unsurpassed soft-tissue contrast with simultaneous device visualization, rtCMR is presumed to allow safe device navigation and to offer optimal orientation for precise axial positioning. We sought to evaluate the preclinical feasibility of rtCMR-guided transarterial aortic valve implatation (TAVI) using the nitinol-based Medtronic CoreValve bioprosthesis. Methods rtCMR-guided transfemoral (n = 2) and transsubclavian (n = 6) TAVI was performed in 8 swine using the original CoreValve prosthesis and a modified, CMR-compatible delivery catheter without ferromagnetic components. Results rtCMR using TrueFISP sequences provided reliable imaging guidance during TAVI, which was successful in 6 swine. One transfemoral attempt failed due to unsuccessful aortic arch passage and one pericardial tamponade with subsequent death occurred as a result of ventricular perforation by the device tip due to an operating error, this complication being detected without delay by rtCMR. rtCMR allowed for a detailed, simultaneous visualization of the delivery system with the mounted stent-valve and the surrounding anatomy, resulting in improved visualization during navigation through the vasculature, passage of the aortic valve, and during placement and deployment of the stent-valve. Post-interventional success could be confirmed using ECG-triggered time-resolved cine-TrueFISP and flow-sensitive phase-contrast sequences. Intended valve position was confirmed by ex-vivo histology. Conclusions Our study shows that rtCMR-guided TAVI using the commercial CoreValve prosthesis in conjunction with a modified delivery system is feasible in swine, allowing improved procedural guidance including immediate detection of complications and direct functional assessment with reduction of radiation and omission of contrast media. PMID:22453050

Towards real-time cardiovascular magnetic resonance guided transarterial CoreValve implantation: in vivo evaluation in swine.

PubMed

Kahlert, Philipp; Parohl, Nina; Albert, Juliane; Schäfer, Lena; Reinhardt, Renate; Kaiser, Gernot M; McDougall, Ian; Decker, Brad; Plicht, Björn; Erbel, Raimund; Eggebrecht, Holger; Ladd, Mark E; Quick, Harald H

2012-03-27

Real-time cardiovascular magnetic resonance (rtCMR) is considered attractive for guiding TAVI. Owing to an unlimited scan plane orientation and an unsurpassed soft-tissue contrast with simultaneous device visualization, rtCMR is presumed to allow safe device navigation and to offer optimal orientation for precise axial positioning. We sought to evaluate the preclinical feasibility of rtCMR-guided transarterial aortic valve implatation (TAVI) using the nitinol-based Medtronic CoreValve bioprosthesis. rtCMR-guided transfemoral (n = 2) and transsubclavian (n = 6) TAVI was performed in 8 swine using the original CoreValve prosthesis and a modified, CMR-compatible delivery catheter without ferromagnetic components. rtCMR using TrueFISP sequences provided reliable imaging guidance during TAVI, which was successful in 6 swine. One transfemoral attempt failed due to unsuccessful aortic arch passage and one pericardial tamponade with subsequent death occurred as a result of ventricular perforation by the device tip due to an operating error, this complication being detected without delay by rtCMR. rtCMR allowed for a detailed, simultaneous visualization of the delivery system with the mounted stent-valve and the surrounding anatomy, resulting in improved visualization during navigation through the vasculature, passage of the aortic valve, and during placement and deployment of the stent-valve. Post-interventional success could be confirmed using ECG-triggered time-resolved cine-TrueFISP and flow-sensitive phase-contrast sequences. Intended valve position was confirmed by ex-vivo histology. Our study shows that rtCMR-guided TAVI using the commercial CoreValve prosthesis in conjunction with a modified delivery system is feasible in swine, allowing improved procedural guidance including immediate detection of complications and direct functional assessment with reduction of radiation and omission of contrast media.

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.

Role of radionuclide imaging for diagnosis of device and prosthetic valve infections

PubMed Central

Sarrazin, Jean-François; Philippon, François; Trottier, Mikaël; Tessier, Michel

2016-01-01

Cardiovascular implantable electronic device (CIED) infection and prosthetic valve endocarditis (PVE) remain a diagnostic challenge. Cardiac imaging plays an important role in the diagnosis and management of patients with CIED infection or PVE. Over the past few years, cardiac radionuclide imaging has gained a key role in the diagnosis of these patients, and in assessing the need for surgery, mainly in the most difficult cases. Both 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and radiolabelled white blood cell single-photon emission computed tomography/computed tomography (WBC SPECT/CT) have been studied in these situations. In their 2015 guidelines for the management of infective endocarditis, the European Society of Cardiology incorporated cardiac nuclear imaging as part of their diagnostic algorithm for PVE, but not CIED infection since the data were judged insufficient at the moment. This article reviews the actual knowledge and recent studies on the use of 18F-FDG PET/CT and WBC SPECT/CT in the context of CIED infection and PVE, and describes the technical aspects of cardiac radionuclide imaging. It also discusses their accepted and potential indications for the diagnosis and management of CIED infection and PVE, the limitations of these tests, and potential areas of future research. PMID:27721936

Stability of Programmable Shunt Valve Settings with Simultaneous Use of the Optune Transducer Array: A Case Report.

PubMed

Chan, Andrew K; Birk, Harjus S; Winkler, Ethan A; Viner, Jennifer A; Taylor, Jennie W; McDermott, Michael W

2016-07-07

The Optune® transducer array (Novocure Ltd., Haifa, Israel) is an FDA-approved noninvasive regional therapy that aims to inhibit the growth of glioblastoma multiforme (GBM) cells via utilization of alternating electric fields. Some patients with GBM may develop hydrocephalus and benefit from subsequent shunt placement, but special attention must be paid to patients in whom programmable valves are utilized, given the potential effect of the magnetic fields on valve settings. We present the first case report illustrating the stability of programmable shunt valve settings in a neurosurgical patient undergoing therapy with the Optune device. In this study, shunt valve settings were stable over a period of five days despite Optune therapy. This is reassuring for patients with GBM who require simultaneous treatment with both the Optune device and a programmable shunt system.

A three-dimensional analysis of the endolymph drainage system in Ménière disease.

PubMed

Monsanto, Rafael da Costa; Pauna, Henrique F; Kwon, Geeyoun; Schachern, Patricia A; Tsuprun, Vladimir; Paparella, Michael M; Cureoglu, Sebahattin

2017-05-01

To measure the volume of the endolymph drainage system in temporal bone specimens with Ménière disease, as compared with specimens with endolymphatic hydrops without vestibular symptoms and with nondiseased specimens STUDY DESIGN: Comparative human temporal bone analysis. We generated three-dimensional models of the vestibular aqueduct, endolymphatic sinus and duct, and intratemporal portion of the endolymphatic sac and calculated the volume of those structures. We also measured the internal and external aperture of the vestibular aqueduct, as well as the opening (if present) of the utriculoendolymphatic (Bast's) valve and compared the measurements in our three study groups. The volume of the vestibular aqueduct and of the endolymphatic sinus, duct, and intratemporal endolymphatic sac was significantly lower in the Ménière disease group than in the endolymphatic hydrops group (P <.05). The external aperture of the vestibular aqueduct was also smaller in the Ménière disease group. Bast's valve was open only in some specimens in the Ménière disease group. In temporal bones with Ménière disease, the volume of the vestibular aqueduct, endolymphatic duct, and intratemporal endolymphatic sac was lower, and the external aperture of the vestibular aqueduct was smaller as compared with bones from donors who had endolymphatic hydrops without vestibular symptoms and with nondiseased bones. The open status of the Bast's valve in the Ménière disease group could be secondary to higher retrograde endolymph pressures caused by smaller drainage systems. These anatomic findings could correlate with the reason that some patients with hydrops develop clinical symptoms, whereas others do not. N/A Laryngoscope, 127:E170-E175, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Application Of Light Valves For Continuous-Tone Printing

NASA Astrophysics Data System (ADS)

Vergona, Albert B.

1989-07-01

New opportunities are emerging in the graphic-arts pre-press market stimulated by the need for digitally created images. To meet this need, we have designed a cost-effective three-color digital printer using PLZT light valves. Transparent lead lanthanum zirconate titanate (PLZT) ceramic crystals when used as a linear modulator offer a number of significant benefits. The primary advantage is that the light valve is an efficient modulator of incoherent light providing a broad spectral output ranging from 400nm to well into the infrared region. In addition, light valves offer the advantages of being small, low cost, have a wide dynamic range (>1000 to 1), and can be used with simple optical designs. The characteristics of the PLZT material plays an important role in the performance of the light valve. A number of variables such as ceramic composition, electrode spacing, and ceramic thickness can be altered to affect its quadratic electrooptic behavior. Additionally, the modulator design requires a closed-loop servo to eliminate the errors caused by the device's remanent polarization and nonlinear behavior.

Exploring the effects of acid mine drainage on diatom teratology using geometric morphometry.

PubMed

Olenici, Adriana; Blanco, Saúl; Borrego-Ramos, María; Momeu, Laura; Baciu, Călin

2017-10-01

Metal pollution of aquatic habitats is a major and persistent environmental problem. Acid mine drainage (AMD) affects lotic systems in numerous and interactive ways. In the present work, a mining area (Roșia Montană) was chosen as study site, and we focused on two aims: (i) to find the set of environmental predictors leading to the appearance of the abnormal diatom individuals in the study area and (ii) to assess the relationship between the degree of valve outline deformation and AMD-derived pollution. In this context, morphological differences between populations of Achnanthidium minutissimum and A. macrocephalum, including normal and abnormal individuals, were evidenced by means of valve shape analysis. Geometric morphometry managed to capture and discriminate normal and abnormal individuals. Multivariate analyses (NMDS, PLS) separated the four populations of the two species mentioned and revealed the main physico-chemical parameters that influenced valve deformation in this context, namely conductivity, Zn, and Cu. ANOSIM test evidenced the presence of statistically significant differences between normal and abnormal individuals within both chosen Achnanthidium taxa. In order to determine the relative contribution of each of the measured physico-chemical parameters in the observed valve outline deformations, a PLS was conducted, confirming the results of the NMDS. The presence of deformed individuals in the study area can be attributed to the fact that the diatom communities were strongly affected by AMD released from old mining works and waste rock deposits.

Development of a smart type motor operated valve for nuclear power plants

NASA Astrophysics Data System (ADS)

Kim, Chang-Hwoi; Park, Joo-Hyun; Lee, Dong-young; Koo, In-Soo

2005-12-01

In this paper, the design concept of the smart type motor operator valve for nuclear power plant was described. The development objective of the smart valve is to achieve superior accuracy, long-term reliability, and ease of use. In this reasons, developed smart valve has fieldbus communication such as deviceNet and Profibus-DP, auto-tuning PID controller, self-diagnostics, and on-line calibration capabilities. And also, to achieve pressure, temperature, and flow control with internal PID controller, the pressure sensor and transmitter were included in this valve. And, temperature and flow signal acquisition port was prepared. The developed smart valve will be performed equipment qualification test such as environment, EMI/EMC, and vibration in Korea Test Lab. And, the valve performance is tested in a test loop which is located in Seoul National University Lab. To apply nuclear power plant, the software is being developed according to software life cycle. The developed software is verified by independent software V and V team. It is expected that the smart valve can be applied to an existing NPPs for replacing or to a new nuclear power plants. The design and fabrication of smart valve is now being processed.

New valve and bonding designs for microfluidic biochips containing proteins.

PubMed

Lu, Chunmeng; Xie, Yubing; Yang, Yong; Cheng, Mark M-C; Koh, Chee-Guan; Bai, Yunling; Lee, L James; Juang, Yi-Je

2007-02-01

Two major concerns in the design and fabrication of microfluidic biochips are protein binding on the channel surface and protein denaturing during device assembly. In this paper, we describe new methods to solve these problems. A "fishbone" microvalve design based on the concept of superhydrophobicity was developed to replace the capillary valve in applications where the chip surface requires protein blocking to prevent nonspecific binding. Our experimental results show that the valve functions well in a CD-like ELISA device. The packaging of biochips containing pre-loaded proteins is also a challenging task since conventional sealing methods often require the use of high temperatures, electric voltages, or organic solvents that are detrimental to the protein activity. Using CO2 gas to enhance the diffusion of polymer molecules near the device surface can result in good bonding at low temperatures and low pressure. This bonding method has little influence on the activity of the pre-loaded proteins after bonding.

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

A fluidic diode, valves, and a sequential-loading circuit fabricated on layered paper.

PubMed

Chen, Hong; Cogswell, Jeremy; Anagnostopoulos, Constantine; Faghri, Mohammad

2012-08-21

Current microfluidic paper-based devices lack crucial components for fluid manipulation. We created a fluidic diode fabricated entirely on a single layer of paper to control the wicking of fluids. The fluidic diode is a two-terminal component that promotes or stops wicking along a paper channel. We further constructed a trigger and a delay valve based on the fluidic diode. Furthermore, we demonstrated a high-level functional circuit, consisting of a diode and a delay valve, to manipulate two fluids in a sequential manner. Our study provides new, transformative tools to manipulate fluid in microfluidic paper-based devices.

Bench evaluation: three face-shield CPR barrier devices.

PubMed

Simmons, M; Deao, D; Moon, L; Peters, K; Cavanaugh, S

1995-06-01

Due to the fear of disease transmission, the practice of mouth-to-mouth (M-M) rescue breathing is rarely performed; to address this concern, many types of CPR barrier devices have been developed. These include bag-valve-mask devices, mouth-to-mask devices, and face shields (FS). The purpose of this study was to measure the volumes delivered during mouth-to-face shield (M-FS) breathing, to measure the back pressure and calculate the resistance to flow through their 1-way valves, and to test for backward leak of gas through the valves. Three FS brands were evaluated: Kiss of Life (KOL), MicroSHIELD (Micro) and Res-Cue Key (RCK). Volume delivered during M-M and M-FS breathing was evaluated by 10 rescuers who used the devices while performing rescue breathing on a CPR mannequin. Back pressure was measured and resistance calculated by directing airflow through the 1-way valves. Backward leak was evaluated by measuring the O2 concentration at the rescuer side of the valve while 100% O2 was directed toward the patient side of the valve. Differences among the brands were evaluated using analysis of variance. The mean (SD) values for volumes in L were: M-M 1.00 (0.25), Micro 0.77 (0.20), RCK 0.64 (0.10), and KOL 0.24 (0.11). Mean values for back pressure in cm H2O at 50 L/min were Micro 16.7 (1.29), KOL 7.22 (0.13), and RCK 2.15 (0.16). Significant backward leak only occurred with RCK. Not one of the FSs tested met all of the requirements suggested by the American Heart Association and by the International Standards Organization.

Dual-channel current valve in a three terminal zigzag graphene nanoribbon junction

NASA Astrophysics Data System (ADS)

Zhang, L.

2017-02-01

We theoretically propose a dual-channel current valve based on a three terminal zigzag graphene nanoribbon (ZGNR) junction driven by three asymmetric time-dependent pumping potentials. By means of the Keldysh Green’s function method, we show that two asymmetric charge currents can be pumped in the different left-right terminals of the device at a zero bias, which mainly stems from the single photon-assisted pumping approximation and the valley valve effect in a ZGNR p-n junction. The ON and OFF states of pumped charge currents are crucially dependent on the even-odd chain widths of the three electrodes, the pumping frequency, the lattice potential and the Fermi level. Two-tunneling spin valves are also considered to spatially separate and detect 100% polarized spin currents owing to the combined spin pump effect and the valley selective transport in a three terminal ZGNR ferromagnetic junction. Our investigations might be helpful to control the spatial and spin degrees of freedom of electrons in graphene pumping devices.

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.

Active control of magnetoresistance of organic spin valves using ferroelectricity

PubMed Central

Sun, Dali; Fang, Mei; Xu, Xiaoshan; Jiang, Lu; Guo, Hangwen; Wang, Yanmei; Yang, Wenting; Yin, Lifeng; Snijders, Paul C.; Ward, T. Z.; Gai, Zheng; Zhang, X.-G.; Lee, Ho Nyung; Shen, Jian

2014-01-01

Organic spintronic devices have been appealing because of the long spin lifetime of the charge carriers in the organic materials and their low cost, flexibility and chemical diversity. In previous studies, the control of resistance of organic spin valves is generally achieved by the alignment of the magnetization directions of the two ferromagnetic electrodes, generating magnetoresistance. Here we employ a new knob to tune the resistance of organic spin valves by adding a thin ferroelectric interfacial layer between the ferromagnetic electrode and the organic spacer: the magnetoresistance of the spin valve depends strongly on the history of the bias voltage, which is correlated with the polarization of the ferroelectric layer; the magnetoresistance even changes sign when the electric polarization of the ferroelectric layer is reversed. These findings enable active control of resistance using both electric and magnetic fields, opening up possibility for multi-state organic spin valves. PMID:25008155

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

Dynamic tracking of prosthetic valve motion and deformation from bi-plane x-ray views: feasibility study

NASA Astrophysics Data System (ADS)

Hatt, Charles R.; Wagner, Martin; Raval, Amish N.; Speidel, Michael A.

2016-03-01

Transcatheter aortic valve replacement (TAVR) requires navigation and deployment of a prosthetic valve within the aortic annulus under fluoroscopic guidance. To support improved device visualization in this procedure, this study investigates the feasibility of frame-by-frame 3D reconstruction of a moving and expanding prosthetic valve structure from simultaneous bi-plane x-ray views. In the proposed method, a dynamic 3D model of the valve is used in a 2D/3D registration framework to obtain a reconstruction of the valve. For each frame, valve model parameters describing position, orientation, expansion state, and deformation are iteratively adjusted until forward projections of the model match both bi-plane views. Simulated bi-plane imaging of a valve at different signal-difference-to-noise ratio (SDNR) levels was performed to test the approach. 20 image sequences with 50 frames of valve deployment were simulated at each SDNR. The simulation achieved a target registration error (TRE) of the estimated valve model of 0.93 +/- 2.6 mm (mean +/- S.D.) for the lowest SDNR of 2. For higher SDNRs (5 to 50) a TRE of 0.04 mm +/- 0.23 mm was achieved. A tabletop phantom study was then conducted using a TAVR valve. The dynamic 3D model was constructed from high resolution CT scans and a simple expansion model. TRE was 1.22 +/- 0.35 mm for expansion states varying from undeployed to fully deployed, and for moderate amounts of inter-frame motion. Results indicate that it is feasible to use bi-plane imaging to recover the 3D structure of deformable catheter devices.

Dynamic tracking of prosthetic valve motion and deformation from bi-plane x-ray views: feasibility study.

PubMed

Hatt, Charles R; Wagner, Martin; Raval, Amish N; Speidel, Michael A

2016-01-01

Transcatheter aortic valve replacement (TAVR) requires navigation and deployment of a prosthetic valve within the aortic annulus under fluoroscopic guidance. To support improved device visualization in this procedure, this study investigates the feasibility of frame-by-frame 3D reconstruction of a moving and expanding prosthetic valve structure from simultaneous bi-plane x-ray views. In the proposed method, a dynamic 3D model of the valve is used in a 2D/3D registration framework to obtain a reconstruction of the valve. For each frame, valve model parameters describing position, orientation, expansion state, and deformation are iteratively adjusted until forward projections of the model match both bi-plane views. Simulated bi-plane imaging of a valve at different signal-difference-to-noise ratio (SDNR) levels was performed to test the approach. 20 image sequences with 50 frames of valve deployment were simulated at each SDNR. The simulation achieved a target registration error (TRE) of the estimated valve model of 0.93 ± 2.6 mm (mean ± S.D.) for the lowest SDNR of 2. For higher SDNRs (5 to 50) a TRE of 0.04 mm ± 0.23 mm was achieved. A tabletop phantom study was then conducted using a TAVR valve. The dynamic 3D model was constructed from high resolution CT scans and a simple expansion model. TRE was 1.22 ± 0.35 mm for expansion states varying from undeployed to fully deployed, and for moderate amounts of inter-frame motion. Results indicate that it is feasible to use bi-plane imaging to recover the 3D structure of deformable catheter devices.

Microfluidic device for drug delivery

NASA Technical Reports Server (NTRS)

MacDonald, Michael J. (Inventor); Eddington, David T. (Inventor); Beebe, David J. (Inventor); Mensing, Glennys A. (Inventor)

2010-01-01

A microfluidic device is provided for delivering a drug to an individual. The microfluidic device includes a body that defines a reservoir for receiving the drug therein. A valve interconnects the reservoir to an output needle that is insertable into the skin of an individual. A pressure source urges the drug from the reservoir toward the needle. The valve is movable between a closed position preventing the flow of the drug from the reservoir to the output needle and an open position allowing for the flow of the drug from the reservoir to the output needle in response to a predetermined condition in the physiological fluids of the individual.

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.

Reduction of shunt current in buffer-free IrMn based spin-valve structures

NASA Astrophysics Data System (ADS)

Kocaman, B.; Akdoğan, N.

2018-06-01

The presence of thick buffer layers in magnetic sensor devices decreases sensor sensitivity due to shunt currents. With this motivation, we produced IrMn-based spin-valve multilayers without using buffer layer. We also studied the effects of post-annealing and IrMn thickness on exchange bias field (HEB) and blocking temperature (TB) of the system. Magnetization measurements indicate that both HEB and TB values are significantly enhanced with post-annealing of IrMn layer. In addition, we report that IrMn thickness of the system strongly influences the magnetization and transport characteristics of the spin-valve structures. We found that the minimum thickness of IrMn layer is 6 nm in order to achieve the lowest shunt current and high blocking temperature (>300 K). We also investigated the training of exchange bias to check the long-term durability of IrMn-based spin-valve structures for device applications.

[Testing system design and analysis for the execution units of anti-thrombotic device].

PubMed