Characteristics of aortic valve dysfunction and ascending aorta dimensions according to bicuspid aortic valve morphology

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Shin, Hong Ju [Konkuk University Medical Center, Konkuk University School of Medicine, Department of Cardiovascular Surgery, Seoul (Korea, Republic of); Yonsei University College of Medicine, Department of Cardiovascular Surgery, Seoul (Korea, Republic of); Shin, Je Kyoun; Chee, Hyun Kun; Kim, Jun Suk [Konkuk University Medical Center, Konkuk University School of Medicine, Department of Cardiovascular Surgery, Seoul (Korea, Republic of); Ko, Sung Min [Konkuk University Medical Center, Konkuk University School of Medicine, Department of Radiology, Seoul (Korea, Republic of)

2015-07-15

To characterize aortic valve dysfunction and ascending aorta dimensions according to bicuspid aortic valve (BAV) morphology using computed tomography (CT) and surgical findings. We retrospectively enrolled 209 patients with BAVs who underwent transthoracic echocardiography (TTE) and CT. BAVs were classified as anterior-posterior (BAV-AP) or lateral (BAV-LA) orientation of the cusps and divided according to the presence (raphe+) or absence (raphe-) of a raphe. Ascending aortic dimensions were measured by CT at four levels. BAV-AP was present in 129 patients (61.7 %) and raphe+ in 120 (57.4 %). Sixty-nine patients (33.0 %) had aortic regurgitation (AR), 70 (33.5 %) had aortic stenosis (AS), and 58 (27.8 %) had combined AS and AR. AR was more common in patients with BAV-AP and raphe+; AS was more common with BAV-LA and raphe-.Annulus/body surface area and tubular portion/body surface area diameters in patients with BAV-AP (17.1 ± 2.3 mm/m{sup 2} and 24.2 ± 5.3 mm/m{sup 2}, respectively) and raphe+ (17.3 ± 2.2 mm/m{sup 2} and 24.2 ± 5.5 mm/m{sup 2}, respectively) were significantly different from those with BAV-LA (15.8 ± 1.9 mm/m{sup 2} and 26.4 ± 5.5 mm/m{sup 2}, respectively) and raphe- (15.7 ± 1.9 mm/m{sup 2} and 26.2 ± 5.4 mm/m{sup 2}, respectively). The morphological characteristics of BAV might be associated with the type of valvular dysfunction, and degree and location of an ascending aorta dilatation. (orig.)

Left Ventricular Function Improves after Pulmonary Valve Replacement in Patients with Previous Right Ventricular Outflow Tract Reconstruction and Biventricular Dysfunction

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Kane, Colin; Kogon, Brian; Pernetz, Maria; McConnell, Michael; Kirshbom, Paul; Rodby, Katherine; Book, Wendy M.

2011-01-01

Congenital heart defects that have a component of right ventricular outflow tract obstruction, such as tetralogy of Fallot, are frequently palliated in childhood by disruption of the pulmonary valve. Although this can provide an initial improvement in quality of life, these patients are often left with severe pulmonary valve insufficiency. Over time, this insufficiency can lead to enlargement of the right ventricle and to the deterioration of right ventricular systolic and diastolic function. Pulmonary valve replacement in these patients decreases right ventricular volume overload and improves right ventricular performance. To date, few studies have examined the effects of pulmonary valve replacement on left ventricular function in patients with biventricular dysfunction. We sought to perform such an evaluation. Records of adult patients who had undergone pulmonary valve replacement from January 2003 through November 2006 were analyzed retrospectively. We reviewed preoperative and postoperative echocardiograms and calculated left ventricular function in 38 patients. In the entire cohort, the mean left ventricular ejection fraction increased by a mean of 0.07 after pulmonary valve replacement, which was a statistically significant change (P < 0.01). In patients with preoperative ejection fractions of less than 0.50, mean ejection fractions increased by 0.10. We conclude that pulmonary valve replacement in patients with biventricular dysfunction arising from severe pulmonary insufficiency and right ventricular enlargement can improve left ventricular function. Prospective studies are needed to verify this finding. PMID:21720459

Correlation of two-dimensional echocardiography and pathologic findings in porcine valve dysfunction.

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Forman, M B; Phelan, B K; Robertson, R M; Virmani, R

1985-02-01

Two-dimensional echocardiographic findings in porcine valve dysfunction were compared with pathologic findings in 10 patients (12 valves). Three specific echocardiographic findings were identified in patients with regurgitant lesions: prolapse, fracture and flail leaflets. Prolapse was associated pathologically with thinning of the leaflets, longitudinal tears close to the ring margin and acid mucopolysaccharide accumulation. Valve fracture was seen with and without prolapse and was accompanied pathologically by small pinpoint perforations or tears of the leaflet. A flail leaflet was seen with a linear tear of the free margin and was associated with calcific deposits. Mild degrees of fracture seen pathologically were missed on the echocardiographic study in five patients. Thickening or calcification, when present in moderate or severe amounts, was correctly identified by echocardiography. When all abnormal features were considered collectively, two-dimensional echocardiography correctly identified at least one of them in all patients. Therefore, two-dimensional echocardiography may prove useful in assessing the source of valvular regurgitation in patients with bioprosthetic valves.

Histopathological and Immunohistochemical Evaluation of Pannus Tissue in Patients with Prosthetic Valve Dysfunction.

Science.gov (United States)

Karakoyun, Süleyman; Ozan Gürsoy, Mustafa; Yesin, Mahmut; Kalçık, Macit; Astarcıoğlu, Mehmet Ali; Gündüz, Sabahattin; Emrah Oğuz, Ali; Çoban Kökten, Şermin; Nimet Karadayı, Ayşe; Tuncer, Altuğ; Köksal, Cengiz; Gökdeniz, Tayyar; Özkan, Mehmet

2016-01-01

Prosthetic valve dysfunction due to pannus formation is a rare but serious complication. Currently, limited data are available concerning the pathogenesis and immunohistochemical properties of pannus. The study aim was to investigate the morphological, histopathological and immunohistochemical characteristics of pannus formation in patients with prosthetic valve dysfunction. A total of 35 patients (10 males, 25 females; mean age 44 ± 16 years) who had undergone re-do valve surgery due to prosthetic valve obstruction was enrolled in the study. Immunohistochemical studies were aimed at evaluating the expression of alphasmooth muscle actin (α-SMA) and desmin in myofibroblasts and smooth muscle cells; epithelial membrane antigen (EMA) in epithelial cells; and CD34, Factor VIII and vascular endothelial growth factor (VEGF) in endothelial cells. Matrix metalloproteinases (MMPs) -2 and -9, and transforming growth factor-beta (TGF-β) were used to demonstrate cytokine release from macrophages, leukocytes, fibroblasts and myofibroblasts. Pannus appeared as a tough and thick tissue hyperplasia which began from outside the suture ring in the periannular region and extended to the inflow and outflow surfaces of the prosthetic valves. Histopathological analysis showed the pannus tissue to consist of chronic inflammatory cells (lymphocytes, plasma cells, macrophages and foreign body giant cells), spindle cells such as myofibroblasts, capillary blood vessels and endothelial cells laying down the lumens. Calcification was present in the pannus tissue of 19 explanted prostheses. Immunohistochemical studies revealed positive α-SMA expression in all patients, whereas 60.5% of patients were positive for desmin, 50% for EMA, 42.1% for VEGF, 39.5% for TBF-β, 42.1% for MMP-2, 86.8% for CD34, and 97.4% for Factor VIII. MMP-9 was negative in all patients. Pannus tissue appears to be formed as the result of a neointimal response in periannular regions of prosthetic valves that consist

Sixty-Four-Section Cardiac Computed Tomography in Mechanical Prosthetic Heart Valve Dysfunction: Thrombus or Pannus.

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Gündüz, Sabahattin; Özkan, Mehmet; Kalçik, Macit; Gürsoy, Ozan Mustafa; Astarcioğlu, Mehmet Ali; Karakoyun, Süleyman; Aykan, Ahmet Çağri; Biteker, Murat; Gökdeniz, Tayyar; Kaya, Hasan; Yesin, Mahmut; Duran, Nilüfer Ekşi; Sevinç, Deniz; Güneysu, Tahsin

2015-12-01

Distinguishing pannus and thrombus in patients with prosthetic valve dysfunction is essential for the selection of proper treatment. We have investigated the utility of 64-slice multidetector computed tomography (MDCT) in distinguishing between pannus and thrombus, the latter amenable to thrombolysis. Sixty-two (23 men, mean age 44±14 years) patients with suspected mechanical prosthetic valve dysfunction assessed by transesophageal echocardiography were included in this prospective observational trial. Subsequently, MDCT was performed before any treatment was started. Periprosthetic masses were detected by MDCT in 46 patients, and their attenuation values were measured as Hounsfield Units (HU). Patients underwent thrombolysis unless contraindicated, and those with a contraindication or failed thrombolysis underwent surgery. A mass which was completely lysed or surgically detected as a clot was classified as thrombus, whereas a mass which was surgically detected as tissue overgrowth was classified as pannus. A definitive diagnosis could be achieved in 37 patients with 39 MDCT masses (22 thrombus and 17 pannus). The mean attenuation value of 22 thrombotic masses was significantly lower than that in 17 pannus (87±59 versus 322±122; Ppannus from thrombus. Complete lysis was more common for masses with HUpannus overgrowth, whereas a lower value is associated with thrombus formation. A higher attenuation (HU>90) is associated with reduced lysis rates. © 2015 American Heart Association, Inc.

Survival after aortic valve replacement for severe aortic stenosis with low transvalvular gradients and severe left ventricular dysfunction

Science.gov (United States)

Pereira, Jeremy J.; Lauer, Michael S.; Bashir, Mohammad; Afridi, Imran; Blackstone, Eugene H.; Stewart, William J.; McCarthy, Patrick M.; Thomas, James D.; Asher, Craig R.

2002-01-01

OBJECTIVE: We sought to assess whether aortic valve replacement (AVR) among patients with severe aortic stenosis (AS), severe left ventricular (LV) dysfunction and a low transvalvular gradient (TVG) is associated with improved survival. BACKGROUND: The optimal management of patients with severe AS with severe LV dysfunction and a low TVG remains controversial. METHODS: Between 1990 and 1998, we evaluated 68 patients who underwent AVR at our institution (AVR group) and 89 patients who did not undergo AVR (control group), with an aortic valve area < or = 0.75 cm(2), LV ejection fraction < or = 35% and mean gradient < or = 30 mm Hg. Using propensity analysis, survival was compared between a cohort of 39 patients in the AVR group and 56 patients in the control group. RESULTS: Despite well-matched baseline characteristics among propensity-matched patients, the one- and four-year survival rates were markedly improved in patients in the AVR group (82% and 78%), as compared with patients in the control group (41% and 15%; p < 0.0001). By multivariable analysis, the main predictor of improved survival was AVR (adjusted risk ratio 0.19, 95% confidence interval 0.09 to 0.39; p < 0.0001). The only other predictors of mortality were age and the serum creatinine level. CONCLUSIONS: Among select patients with severe AS, severe LV dysfunction and a low TVG, AVR was associated with significantly improved survival.

Transient severe left ventricular dysfunction following percutaneous patent ductus arteriosus closure in an adult with bicuspid aortic valve: A case report.

Science.gov (United States)

Hwang, Hui-Jeong; Yoon, Kyung Lim; Sohn, Il Suk

2016-03-01

The present study reported the case of a 60-year-old female with patent ductus arteriosus (PDA) and a bicuspid aortic valve, who presented with transient severe left ventricular (LV) dysfunction following percutaneous closure of PDA, as identified by speckle tracking analysis. Transient LV dysfunction following PDA closure has previously been reported; however, severe LV dysfunction is rare. In the present case, the combination of a large PDA size, large amount of shunting, LV remodeling and bicuspid aortic valve may have induced serious deterioration of LV function following PDA closure. Furthermore, speckle-tracking echocardiography may be useful in the estimation of functional alterations in the myocardium of the LV following PDA closure. The observations detailed in the present study may improve the understanding of the pathophysiology and myocardial patterns of transient left ventricular dysfunction following PDA closure in adult humans.

Long-term bladder dysfunction and renal function in boys with posterior urethral valves based on urodynamic findings

NARCIS (Netherlands)

M.A.I. Ghanem (Mazen); K.P. Wolffenbuttel (Katja); A. de Vylder (Ann); R.J.M. Nijman (Rien)

2004-01-01

textabstractPurpose: Posterior urethral valves are the most common cause of congenital obstructive uropathy leading to renal failure in childhood. We investigate the influence of bladder dysfunction on renal function impairment. Materials and Methods: We retrospectively reviewed the records of 116

Long-term bladder dysfunction and renal function in boys with posterior urethral valves based on urodynamic findings

NARCIS (Netherlands)

Ghanem, MA; Wolffenbuttel, KP; De Vylder, A; Nijman, RJ

Purpose: Posterior urethral valves are the most common cause of congenital obstructive uropathy leading to renal failure in childhood. We investigate the influence of bladder dysfunction on renal function impairment. Materials and Methods: We retrospectively reviewed the records of 116 patients with

Is valve choice a significant determinant of paravalular leak post-transcatheter aortic valve implantation? A systematic review and meta-analysis.

Science.gov (United States)

O'Sullivan, Katie E; Gough, Aideen; Segurado, Ricardo; Barry, Mitchel; Sugrue, Declan; Hurley, John

2014-05-01

Paravalvular regurgitation (PVR) following transcatheter aortic valve implantation (TAVI) is associated with poor survival. The two main valve delivery systems used to date differ significantly in both structure and deployment technique. The primary objective of this study was to perform a systematic review and meta-analysis of studies identifying PVR in patients post-TAVI using Medtronic CoreValve (MCV) and Edward Sapien (ES) valves in order to identify whether a significant difference exists between valve types. The secondary objective was to identify additional factors predisposing to PVR to provide an overview of the other associated considerations. A systematic review and meta-analysis of the current literature to identify PVR rate in patients with MCV and ES valves was performed. We also sought to examine other factors predisposing to PVR. A total of 5910 patients were identified from 9 studies. PVR rates for MCV and ES were analysed. MCV was associated with a higher PVR rate of 15.75% [95% confidence interval (CI) 12.48-19.32] compared with ES 3.93% [95% CI 1.05-8.38]. We separately reviewed predisposing factors associated with PVR. A formal comparison of the MCV and ES valve leakage rates by mixed-effects meta-regression with a fixed-effect moderator variable for valve type (MCV or ES) suggested a statistically significant difference in leakage rate between the two valve types (P = 0.0002). Unfavourable anatomical and pathological factors as well as valve choice have an impact on rates of PVR. Additionally, certain anatomical features dictate valve choice. A direct comparison of all the predisposing factors at this time is not possible and will require prospective multivariate analysis. There is, however, a significant difference in the PVR rates between valves based on the published observational data available to date. The ES valve associated with a lower incidence of PVR overall; therefore, we conclude that valve choice is indeed a significant

Delayed onset of tricuspid valve flow in repaired tetralogy of Fallot: an additional mechanism of diastolic dysfunction and interventricular dyssynchrony

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Benson Lee N

2011-08-01

Full Text Available Abstract Background Diastolic dysfunction of the right ventricle (RV is common after repair of tetralogy of Fallot. While restrictive physiology in late diastole has been well known, dysfunction in early diastole has not been described. The present study sought to assess the prevalence and mechanism of early diastolic dysfunction of the RV defined as delayed onset of the tricuspid valve (TV flow after TOF repair. Methods The study population consisted of 31 children with repaired TOF (mean age ± SD, 12.3 ± 4.1 years who underwent postoperative cardiovascular magnetic resonance (CMR. The CMR protocol included simultaneous phase-contrast velocity mapping of the atrioventricular valves, which enabled direct comparison of the timing and patterns of tricuspid (TV and mitral (MV valve flow. The TV flow was defined to have delayed onset when its onset was > 20 ms later than the onset of the MV flow. The TV and MV flow from 14 normal children was used for comparison. The CMR results were correlated with the findings on echocardiography and electrocardiography. Result Delayed onset of the TV flow was observed in 16/31 patients and in none of the controls. The mean delay time was 64.81 ± 27.07 ms (8.7 ± 3.2% of R-R interval. The delay time correlated with the differences in duration of the TV and MV flow (55.94 ± 32.88 ms (r = 0.90, p Conclusions Early diastolic dysfunction with delayed onset of TV flow is common after TOF repair, and is associated with reduced RV ejection fraction. It is a further manifestation of interventricular dyssynchrony and represent an additional mechanism of ventricular diastolic dysfunction.

Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

DEFF Research Database (Denmark)

Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas

2010-01-01

Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacemen....... We report the first case of surgical valve replacement in a patient with a dysfunctional transcatheter-implanted aortic valve prosthesis 4 months after implantation....

Is valve choice a significant determinant of paravalular leak post-transcatheter aortic valve implantation? A systematic review and meta-analysis.

LENUS (Irish Health Repository)

O'Sullivan, Katie E

2013-11-01

Paravalvular regurgitation (PVR) following transcatheter aortic valve implantation (TAVI) is associated with poor survival. The two main valve delivery systems used to date differ significantly in both structure and deployment technique. The primary objective of this study was to perform a systematic review and meta-analysis of studies identifying PVR in patients post-TAVI using Medtronic CoreValve (MCV) and Edward Sapien (ES) valves in order to identify whether a significant difference exists between valve types. The secondary objective was to identify additional factors predisposing to PVR to provide an overview of the other associated considerations.

Transient severe left ventricular dysfunction following percutaneous patent ductus arteriosus closure in an adult with bicuspid aortic valve: A case report

OpenAIRE

HWANG, HUI-JEONG; YOON, KYUNG LIM; SOHN, IL SUK

2016-01-01

The present study reported the case of a 60-year-old female with patent ductus arteriosus (PDA) and a bicuspid aortic valve, who presented with transient severe left ventricular (LV) dysfunction following percutaneous closure of PDA, as identified by speckle tracking analysis. Transient LV dysfunction following PDA closure has previously been reported; however, severe LV dysfunction is rare. In the present case, the combination of a large PDA size, large amount of shunting, LV remodeling and ...

Prognostic Implications of Raphe in Bicuspid Aortic Valve Anatomy.

Science.gov (United States)

Kong, William K F; Delgado, Victoria; Poh, Kian Keong; Regeer, Madelien V; Ng, Arnold C T; McCormack, Louise; Yeo, Tiong Cheng; Shanks, Miriam; Parent, Sarah; Enache, Roxana; Popescu, Bogdan A; Liang, Michael; Yip, James W; Ma, Lawrence C W; Kamperidis, Vasileios; van Rosendael, Philippe J; van der Velde, Enno T; Ajmone Marsan, Nina; Bax, Jeroen J

2017-03-01

Little is known about the association between bicuspid aortic valve (BAV) morphologic findings and the degree of valvular dysfunction, presence of aortopathy, and complications, including aortic valve surgery, aortic dissection, and all-cause mortality. To investigate the association between BAV morphologic findings (raphe vs nonraphe) and the degree of valve dysfunction, presence of aortopathy, and prognosis (including need for aortic valve surgery, aortic dissection, and all-cause mortality). In this large international multicenter registry of patients with BAV treated at tertiary referral centers, 2118 patients with BAV were evaluated. Patients referred for echocardiography from June 1, 1991, through November 31, 2015, were included in the study. Clinical and echocardiographic data were analyzed retrospectively. The morphologic BAV findings were categorized according to the Sievers and Schmidtke classification. Aortic valve function was divided into normal, regurgitation, or stenosis. Patterns of BAV aortopathy included the following: type 1, dilation of the ascending aorta and aortic root; type 2, isolated dilation of the ascending aorta; and type 3, isolated dilation of the sinus of Valsalva and/or sinotubular junction. Association between the presence and location of raphe and the risk of significant (moderate and severe) aortic valve dysfunction and aortic dilation and/or dissection. Of the 2118 patients (mean [SD] age, 47 [18] years; 1525 [72.0%] male), 1881 (88.8%) had BAV with fusion raphe, whereas 237 (11.2%) had BAV without raphe. Bicuspid aortic valves with raphe had a significantly higher prevalence of valve dysfunction, with a significantly higher frequency of aortic regurgitation (622 [33.1%] vs 57 [24.1%], P < .001) and aortic stenosis (728 [38.7%] vs 51 [21.5%], P < .001). Furthermore, aortic valve replacement event rates were significantly higher among patients with BAV with raphe (364 [19.9%] at 1 year, 393 [21.4%] at 2 years, and 447

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

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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 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.

Mathematical multi-scale model of the cardiovascular system including mitral valve dynamics. Application to ischemic mitral insufficiency

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Moonen Marie

2011-09-01

Full Text Available Abstract Background Valve dysfunction is a common cardiovascular pathology. Despite significant clinical research, there is little formal study of how valve dysfunction affects overall circulatory dynamics. Validated models would offer the ability to better understand these dynamics and thus optimize diagnosis, as well as surgical and other interventions. Methods A cardiovascular and circulatory system (CVS model has already been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiologically accurate "open on pressure, close on flow" law. However, it does not consider real-time valve opening dynamics and therefore does not fully capture valve dysfunction, particularly where the dysfunction involves partial closure. This research describes an updated version of this previous closed-loop CVS model that includes the progressive opening of the mitral valve, and is defined over the full cardiac cycle. Results Simulations of the cardiovascular system with healthy mitral valve are performed, and, the global hemodynamic behaviour is studied compared with previously validated results. The error between resulting pressure-volume (PV loops of already validated CVS model and the new CVS model that includes the progressive opening of the mitral valve is assessed and remains within typical measurement error and variability. Simulations of ischemic mitral insufficiency are also performed. Pressure-Volume loops, transmitral flow evolution and mitral valve aperture area evolution follow reported measurements in shape, amplitude and trends. Conclusions The resulting cardiovascular system model including mitral valve dynamics provides a foundation for clinical validation and the study of valvular dysfunction in vivo. The overall models and results could readily be generalised to other cardiac valves.

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

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

2015-06-01

Pulmonary valve disruption in patients with tetralogy of Fallot and congenital pulmonary stenosis often results in pulmonary insufficiency, right ventricular dilation, and tricuspid valve regurgitation. Management of functional tricuspid regurgitation at the time of subsequent pulmonary valve replacement remains controversial. Our aims were to (1) analyze tricuspid valve function after pulmonary valve replacement through midterm follow-up and (2) determine the benefits, if any, of concomitant tricuspid annuloplasty. Thirty-five patients with tetralogy of Fallot or congenital pulmonary stenosis were analyzed. All patients had been palliated in childhood by disrupting the pulmonary valve, and all patients had at least moderate tricuspid valve regurgitation at the time of subsequent pulmonary valve replacement. Preoperative and serial postoperative echocardiograms were analyzed. Pulmonary and tricuspid regurgitation, along with right ventricular dilation and dysfunction were scored as 0 (none), 1 (mild), 2 (moderate), and 3 (severe). Right ventricular volume and area were also calculated. Comparisons were made between patients who underwent pulmonary valve replacement alone and those who underwent concomitant tricuspid valve annuloplasty. At 1 month after pulmonary valve replacement, there were significant reductions in pulmonary valve regurgitation (mean 3 vs 0.39, p tricuspid valve regurgitation (mean 2.33 vs 1.3, p tricuspid regurgitation 1 month postoperatively between patients who underwent concomitant tricuspid annuloplasty and those who underwent pulmonary valve replacement alone (mean 1.31 vs 1.29, p = 0.81). However, at latest follow-up (mean 7.0 ± 2.8 years), the degree of tricuspid regurgitation was significantly higher in the concomitant annuloplasty group (mean 1.87 vs 1.12, p = 0.005). In patients with at least moderate tricuspid valve regurgitation, significant improvement in tricuspid valve function and right ventricular size occurs in the first

Implante valve-in-valve transcateter em posição aórtica: uma mudança de seleção? Transcatheter aortic valve-in-valve implantation: a selection change?

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Diego Felipe Gaia

2012-09-01

. Minimally invasive transcatheter aortic "valve-in-valve" implant appears to be an alternative, reducing morbidity and mortality. The objective is to evaluate aortic valve-in-valve procedure using Braile Inovare prosthesis. METHODS: The Braile Inovare prosthesis, transcatheter, expandable balloon, was used in 14 cases. Average EuroSCORE was 42.9%. All patients had double aortic bioprosthesis dysfunction. Procedures were performed in a surgical hybrid environment under echocardiographic and fluoroscopic guidance. Using left minithoracotomy prostheses were implanted through the ventricular apex under high-frequency ventricular pacing. Serial clinical and echocardiographic controls were performed. Follow-up ranged 1-30 months. RESULTS: Correct prosthetic deployment was obtained in all cases. There was no conversion. There was no operative mortality. The 30-day mortality was 14.3% (two cases. Ejection fraction increased significantly after the 7th postoperative day. Aortic gradient significantly reduced. The residual aortic regurgitation was not present. There were no vascular complications or complete atrioventricular block. CONCLUSION: The transcatheter "valve-in-valve" procedure for bioprosthesis dysfunction is safe with low morbidity. This possibility may change prosthesis choice during the first aortic valve replacement, favoring bioprostheses.

Safety significance of inadvertent operation of motor-operated valves in nuclear power plants

International Nuclear Information System (INIS)

Ruger, C.J.; Higgins, J.C.; Carbonaro, J.F.; Hall, R.E.

1994-01-01

Concerns about the consequences of valve mispositioning were brought to the forefront following an event at Davis Besse in 1985. The concern related to the ability to reposition open-quotes position-changeableclose quotes motor-operated valves (MOVs) from the control room in the event of their inadvertent operation and was documented in U.S. Nuclear Regulatory Commission (USNRC) Bulletin 85-03 and Generic Letter (GL) 89-10. The mispositioned MOVs may not be able to be returned to their required position due to high differential pressure or high flow conditions across the valves. The inability to reposition such valves may have significantly safety consequences, as in the Davis Besse event. However, full consideration of such mispositioning in safety analyses and in MOV test programs can be labor intensive and expensive. Industry raised concerns that consideration of position-changeable valves under GL 89-10 would not decrease the probability of core damage to an extent that would justify licensee costs. As a response, Brookhaven National Laboratory has conducted separate scoping studies for both boiling water reactors (BWRs) and pressurized water reactors (PWRs) using probabilistic risk assessment (PRA) techniques to determine if such valve mispositioning by itself is significant to safety. The approach used internal events PRA models to survey the order of magnitude of the risk-significance of valve mispositioning by considering the failure of selected position-changeable MOVs. The change in core damage frequency was determined for each valve considered, and the results were presented as a risk increase ratio for each of four assumed MOV failure rates. The risk increase ratios resulting from this failure rate sensitivity study can be used as a basis for a determination of the risk-significance of the MOV mispositioning issues for BWRs and PWRs

Multidetector-row computed tomography for prosthetic heart valve dysfunction: is concomitant non-invasive coronary angiography possible before redo-surgery?

Energy Technology Data Exchange (ETDEWEB)

Tanis, Wilco [Haga Teaching Hospital, Department of Cardiology, The Hague (Netherlands); Haga Teaching Hospital, The Hague (Netherlands); Sucha, Dominika; Habets, Jesse [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Laufer, Ward; Chamuleau, Steven [University Medical Center Utrecht, Department of Cardiology, Utrecht (Netherlands); Herwerden, Lex.A. van [University Medical Center Utrecht, Department of Cardiothoracic Surgery, Utrecht (Netherlands); Symersky, Petr [Vrije Universiteit, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); Budde, Ricardo P.J. [Erasmus Medical Center, Department of Radiology, Rotterdam (Netherlands)

2015-06-01

Retrospective ECG-gated multidetector-row computed tomography (MDCT) is increasingly used for the assessment of prosthetic heart valve (PHV) dysfunction, but is also hampered by PHV-related artefacts/cardiac arrhythmias. Furthermore, it is performed without nitroglycerine or heart rate correction. The purpose was to determine whether MDCT performed before potential redo-PHV surgery is feasible for concomitant coronary artery stenosis assessment and can replace invasive coronary angiography (CAG). PHV patients with CAG and MDCT were identified. Based on medical history, two groups were created: (I) patients with no known coronary artery disease (CAD), (II) patients with known CAD. All images were scored for the presence of significant (>50 %) stenosis. CAG was the reference test. Fifty-one patients were included. In group I (n = 38), MDCT accurately ruled out significant stenosis in 19/38 (50 %) patients, but could not replace CAG in the remaining 19/38 (50 %) patients due to non-diagnostic image quality (n = 16) or significant stenosis (n = 3) detection. In group II (n = 13), MDCT correctly found no patients without significant stenosis, requiring CAG imaging in all. MDCT assessed patency in 16/19 (84 %) grafts and detected a hostile anatomy in two. MDCT performed for PHV dysfunction assessment can replace CAG (100 % accurate) in approximately half of patients without previously known CAD. (orig.)

Multidetector-row computed tomography for prosthetic heart valve dysfunction: is concomitant non-invasive coronary angiography possible before redo-surgery?

International Nuclear Information System (INIS)

Tanis, Wilco; Sucha, Dominika; Habets, Jesse; Laufer, Ward; Chamuleau, Steven; Herwerden, Lex.A. van; Symersky, Petr; Budde, Ricardo P.J.

2015-01-01

Retrospective ECG-gated multidetector-row computed tomography (MDCT) is increasingly used for the assessment of prosthetic heart valve (PHV) dysfunction, but is also hampered by PHV-related artefacts/cardiac arrhythmias. Furthermore, it is performed without nitroglycerine or heart rate correction. The purpose was to determine whether MDCT performed before potential redo-PHV surgery is feasible for concomitant coronary artery stenosis assessment and can replace invasive coronary angiography (CAG). PHV patients with CAG and MDCT were identified. Based on medical history, two groups were created: (I) patients with no known coronary artery disease (CAD), (II) patients with known CAD. All images were scored for the presence of significant (>50 %) stenosis. CAG was the reference test. Fifty-one patients were included. In group I (n = 38), MDCT accurately ruled out significant stenosis in 19/38 (50 %) patients, but could not replace CAG in the remaining 19/38 (50 %) patients due to non-diagnostic image quality (n = 16) or significant stenosis (n = 3) detection. In group II (n = 13), MDCT correctly found no patients without significant stenosis, requiring CAG imaging in all. MDCT assessed patency in 16/19 (84 %) grafts and detected a hostile anatomy in two. MDCT performed for PHV dysfunction assessment can replace CAG (100 % accurate) in approximately half of patients without previously known CAD. (orig.)

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

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

2017-01-01

receiving a biological valve compared to patients receiving a mechanical valve. A large, multicenter retrospective study included in our meta-analysis suggested that any mortality risk of the biological valve group was significant higher than that of the mechanical valve group. However, the risk was no different after risk was adjusted. So, we thought the reason for this result may be related to the characteristics of the patient rather than valve dysfunction. It is still necessary to future randomized studies to verify this conclusion.

Next-generation nozzle check valve significantly reduces operating costs

Energy Technology Data Exchange (ETDEWEB)

Roorda, O. [SMX International, Toronto, ON (Canada)

2009-01-15

Check valves perform an important function in preventing reverse flow and protecting plant and mechanical equipment. However, the variety of different types of valves and extreme differences in performance even within one type can change maintenance requirements and life cycle costs, amounting to millions of dollars over the typical 15-year design life of piping components. A next-generation non-slam nozzle check valve which prevents return flow has greatly reduced operating costs by protecting the mechanical equipment in a piping system. This article described the check valve varieties such as the swing check valve, a dual-plate check valve, and nozzle check valves. Advancements in optimized design of a non-slam nozzle check valve were also discussed, with particular reference to computer flow modelling such as computational fluid dynamics; computer stress modelling such as finite element analysis; and flow testing (using rapid prototype development and flow loop testing), both to improve dynamic performance and reduce hydraulic losses. The benefits of maximized dynamic performance and minimized pressure loss from the new designed valve were also outlined. It was concluded that this latest non-slam nozzle check valve design has potential applications in natural gas, liquefied natural gas, and oil pipelines, including subsea applications, as well as refineries, and petrochemical plants among others, and is suitable for horizontal and vertical installation. The result of this next-generation nozzle check valve design is not only superior performance, and effective protection of mechanical equipment but also minimized life cycle costs. 1 fig.

Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

DEFF Research Database (Denmark)

Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas

2010-01-01

Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacemen...

Heart valve replacements with regenerative capacity

NARCIS (Netherlands)

Dijkman, P.E.; Fioretta, E.S.; Frese, L.; Pasqualini, F.S.; Hoerstrup, S.P.

2016-01-01

The incidence of severe valvular dysfunctions (e.g., stenosis and insufficiency) is increasing, leading to over 300,000 valves implanted worldwide yearly. Clinically used heart valve replacements lack the capacity to grow, inherently requiring repetitive and high-risk surgical interventions during

Computed Tomography of Prosthetic Heart Valves

NARCIS (Netherlands)

Habets, J.

2012-01-01

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

Aortic valve function after bicuspidization of the unicuspid aortic valve.

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Aicher, Diana; Bewarder, Moritz; Kindermann, Michael; Abdul-Khalique, Hashim; Schäfers, Hans-Joachim

2013-05-01

Unicuspid aortic valve (UAV) anatomy leads to dysfunction of the valve in young individuals. We introduced a reconstructive technique of bicuspidizing the UAV. Initially we copied the typical asymmetry of a normal bicuspid aortic valve (BAV) (I), later we created a symmetric BAV (II). This study compared the hemodynamic function of the two designs of a bicuspidized UAV. Aortic valve function was studied at rest and during exercise in 28 patients after repair of UAV (group I, n = 8; group II, n = 20). There were no differences among the groups I and II with respect to gender, age, body size, or weight. All patients were in New York Heart Association class I. Six healthy adults served as control individuals. All patients were studied with transthoracic echocardiography between 4 and 65 months postoperatively. Systolic gradients were assessed by continuous wave Doppler while patients were at rest and exercising on a bicycle ergometer. Aortic regurgitation was grade I or less in all patients. Resting gradients were significantly elevated in group I compared with group II and control individuals (group I, peak 33.8 ± 7.8 mm Hg; mean 19.1 ± 5.4 mm Hg; group II, peak 15.8 ± 5.4, mean 8.2 ± 2.8 mm Hg; control individuals, peak 6.0 ± 1.6, mean 3.2 ± 0.8 mm Hg; p competence. A symmetric repair design leads to improved systolic aortic valve function at rest and during exercise. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Acute obstruction by Pannus in patients with aortic medtronic-hall valves: 30 years of experience.

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Ellensen, Vegard Skalstad; Andersen, Knut Sverre; Vitale, Nicola; Davidsen, Einar Skulstad; Segadal, Leidulf; Haaverstad, Rune

2013-12-01

Acute dysfunction of mechanical aortic valve prostheses is a life-threatening adverse event. Pannus overgrowth, which is fibroelastic hyperplasia originating from the periannular area, is one cause of dysfunction. The aim of this study was to determine the annual incidence of readmittance resulting from acute obstruction caused by pannus during 30 years of observation in patients with Medtronic-Hall aortic valve prostheses and to analyze the risk factors associated with pannus development. From 1982 to 2004, 1,187 patients in our department underwent aortic valve replacement with Medtronic-Hall mechanical monoleaflet valve prostheses. As of December 31, 2012, 27 of these patients (2.3%) had presented with acute valve dysfunction caused by pannus obstruction. The annual incidence of pannus was 0.7 per 1,000. The median time from the primary operation to prosthetic dysfunction was 11.1 years (range, 1.2 to 26.8 years). Of the 20 patients who underwent reoperation, 2 died. Seven patients died before reoperation. Women had a higher risk for the development of obstructing pannus, and patients with pannus obstruction were younger. Valve size was not an independent risk factor. Women and younger patients are at higher risk for pannus development. When acute dysfunction by pannus is suspected in a mechanical aortic valve, an immediate echocardiogram and an emergency aortic valve replacement should be carried out because of the potential of a fatal outcome. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Long-Term Risk for Aortic Complications After Aortic Valve Replacement in Patients With Bicuspid Aortic Valve Versus Marfan Syndrome.

Science.gov (United States)

Itagaki, Shinobu; Chikwe, Joanna P; Chiang, Yuting P; Egorova, Natalia N; Adams, David H

2015-06-09

Bicuspid aortic valves are associated with valve dysfunction, ascending aortic aneurysm and dissection. Management of the ascending aorta at the time of aortic valve replacement (AVR) in these patients is controversial and has been extrapolated from experience with Marfan syndrome, despite the absence of comparative long-term outcome data. This study sought to assess whether the natural history of thoracic aortopathy after AVR in patients with bicuspid aortic valve disease is substantially different from that seen in patients with Marfan syndrome. In this retrospective comparison, outcomes of 13,205 adults (2,079 with bicuspid aortic valves, 73 with Marfan syndrome, and 11,053 control patients with acquired aortic valve disease) who underwent primary AVR without replacement of the ascending aorta in New York State between 1995 and 2010 were compared. The median follow-up time was 6.6 years. The long-term incidence of thoracic aortic dissection was significantly higher in patients with Marfan syndrome (5.5 ± 2.7%) compared with those with bicuspid valves (0.55 ± 0.21%) and control group patients (0.41 ± 0.08%, p Marfan syndrome (10.8 ± 4.4%) compared with those with bicuspid valves (4.8 ± 0.8%) and control group patients (1.4 ± 0.2%) (p Marfan syndrome were significantly more likely to undergo thoracic aortic surgery in late follow-up (10.4 ± 4.3%) compared with those with bicuspid valves (2.5 ± 0.6%) and control group patients (0.50 ± 0.09%) (p Marfan syndrome compared with those with bicuspid aortic valves confirm that operative management of patients with bicuspid aortic valves should not be extrapolated from Marfan syndrome and support discrete treatment algorithms for these different clinical entities. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Factors influencing mortality after bioprosthetic valve replacement; a midterm outcome.

Science.gov (United States)

Javadzadegan, Hassan; Javadzadegan, Amir; Mehdizadeh Baghbani, Jafar

2013-01-01

Although valve repair is applied routinely nowadays, particularly for mitral regurgitation (MR) or tricuspid regurgitation (TR), valve replacement using prosthetic valves is also common especially in adults. Unfortunately the valve with ideal hemodynamic performance and long-term durability without increasing the risk of bleeding due to long-term anticoagulant therapy has not been introduced. Therefore, patients and physicians must choose either bioprosthetic or mechanical valves. Currently, there is an increasing clinical trend of using bioprosthetic valves instead of mechanical valves even in young patients apparently because of their advantages. Seventy patients undergone valvular replacement using bioprosthetic valves were evaluated by ECG and Echocardiography to assess the rhythm and ejection fracture. Mean follow-up time was 33 months (min 9, max 92). Mortality rate was 25.9% (n=18) within 8 years of follow-up. Statistical analysis showed a significant relation between atrial fibrillation rhythm and mortality (P=0.02). Morbidities occurred in 30 patients (42.8%). Significant statistical relation was found between the morbidities and age over 65 years old (P=0.005). In follow-up period, 4 cases (5.7%) underwent re-operation due to global valve dysfunction. Our study shows that using biprosthetic valve could reduce the risk of morbidity occurrence in patient who needs valve replacement. However, if medical treatments fail, patients should be referred for surgery. This would reduce the risk of mortality because of lower incident of complications such as atrial fibrillation and morbidities due to younger patients' population.

Red flag in the emergency department: fracture and primary failure of a prosthetic valve.

Science.gov (United States)

Ozsarac, Murat; Karcioglu, Ozgur; Ayrik, Cuneyt; Bozkurt, Seyran; Turkcuer, Ibrahim; Gumrukcu, Serhat

2005-07-01

This case report concerns a patient with fracture and primary dysfunction of a prosthetic valve. A 40-year-old man presented to the Emergency Department with a chief complaint of breakthrough pleuritic back pain and shortness of breath. Past surgical history was significant only for an aortic valve replacement and mitral valve replacement performed 16 years prior. The transthoracic echocardiography raised suspicion of prosthesis malposition. The patient was taken to the operating room by cardiothoracic surgeons for valve replacement. Operative findings revealed that a prosthetic valve leaflet in the mitral position had broken off. Primary prosthetic valve failure should not be overlooked in the differential diagnosis of patients with valve replacement and a rapidly deteriorating clinical course. Emergency echocardiography is a guide to convenient diagnosis and management. Early surgical consultation and early reparative surgery might prevent unnecessary morbidity and mortality.

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

Science.gov (United States)

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

2016-01-01

Mitral valve prolapse (MVP) results from the systolic movement of a portion(s) or segment(s) of the mitral valve leaflet(s) into the left atrium during left ventricular (LV) systole. It should be emphasised that MVP alone, as defined by imaging techniques, may comprise a non-specific finding because it also depends on the LV volume, myocardial contractility and other LV hemodynamics. Thus, a floppy mitral valve (FMV) should be the basis for the diagnosis of MVP. Two types of symptoms may be defined in these patients. In one group, symptoms are directly related to progressive mitral regurgitation and its complications. In the other group, symptoms cannot be explained only by the degree of mitral regurgitation alone; neuroendocrine dysfunction has been implicated for the explanation of symptoms in this group of patients that today is referred as the FMV/MVP syndrome. When significant mitral regurgitation is present in a patient with FMV/MVP, surgical intervention is recommended. In patients with a prohibitive risk for surgery, transcatheter mitral valve repair using a mitraclip device may be considered. Furthermore, transcatheter mitral valve replacement may represent an option in the near future as clinical trials are underway. In this brief review, the current concepts related to FMV/MVP and FMV/MVP syndrome will be discussed. Copyright © 2016 Hellenic Cardiological Society. Published by Elsevier B.V. All rights reserved.

Perivalvular pannus and valve thrombosis: two concurrent mechanisms of mechanical valve prosthesis dysfunction.

Science.gov (United States)

Arnáiz-García, María Elena; González-Santos, Jose María; Bueno-Codoñer, María E; López-Rodríguez, Javier; Dalmau-Sorlí, María José; Arévalo-Abascal, Adolfo; Arribas-Jiménez, Antonio; Diego-Nieto, Alejandro; Rodríguez-Collado, Javier; Rodríguez-López, Jose María

2015-02-01

A 78-year-old woman was admitted to our institution with progressive dyspnea. She had previously been diagnosed with rheumatic heart disease and had undergone cardiac surgery for mechanical mitral valve replacement ten years previously. Transesophageal echocardiography revealed blockage of the mechanical prosthesis and the patient was scheduled for surgery, in which a thrombus was removed from the left atrial appendage. A partial thrombosis of the mechanical prosthesis and circumferential pannus overgrowth were concomitantly detected. Prosthetic heart valve blockage is a rare but life-threatening complication, the main causes of which are thrombosis and pannus formation. The two conditions are different but both are usually misdiagnosed. Two concurrent mechanisms of prosthesis blockage were found in this patient. Copyright © 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Acute failure of a St. Jude's prosthetic aortic valve: large pannus formation masked by a small thrombus.

Science.gov (United States)

Hurwitz, Seth Eric; Waxman, Daniel; Hecht, Susan

2009-09-01

Pannus formation and valve thrombus can cause prosthetic valve failure. The authors report the case of a 50-year-old woman who presented to the emergency room with decompensated heart failure secondary to mechanical valve dysfunction. On two-dimensional and transesophageal echocardiography, the patient had severe aortic stenosis and regurgitation. A thrombus seen on the valve was felt to be the etiology of her prosthetic valve failure. She underwent emergent cardiac surgery for aortic valve replacement. Pathology revealed that although a small thrombus was present, extensive pannus was the underlying mechanism of valve dysfunction. Differentiation between pannus and thrombus may have important clinical implications, but this case illustrates that distinguishing between these entities by echocardiographic and clinical criteria may not be possible.

DIAGNOSTICS AND TREATMENT OF MITRAL VALVE PROLAPSE

Directory of Open Access Journals (Sweden)

D. A. Kuzhel

2010-01-01

Full Text Available The mitral valve prolapse (MVP is one of the most inconsistent diagnose. In the most cases patients with MVP have the good long-term prognosis, and therapy is aimed at reduction in psychovegetative dysfunction. Careful follow-up and timely cardiosurgical correction should be performed, if necessary, in patients with classical MPV. The choice method in these cases is the mitral valve plasty.

EFFECT OF THYROID DYSFUNCTION IN ANTENATAL MOTHERS

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Anasooya Parail Sankaran

2016-12-01

Full Text Available BACKGROUND The aim of the study is to study the effect of thyroid dysfunction in antenatal mothers in Alappuzha one of the coastal areas in South Kerala over a period from January 2012 to January 2015. MATERIALS AND METHODS It is a descriptive study of the effect of thyroid dysfunction among pregnant ladies attending OBG Department in Government Medical College, Alappuzha, a rural medical college at coastal areas of Kerala over a period of 3 years. RESULTS The incidence is found to be maximum in the coastal area, i.e. 84.9%, but p-valve 0.625 is not statistically significant. Thyroid disorder is mostly seen in primigravida (57.8% and between the age of 20 and 25 yrs. (43.2% and the most commonly seen disorder among is subclinical hypothyroidism (73.7% (p valve <.005, which is statistically significant. There is significant increase in maternal complications like preeclampsia, (RR-8.54, p-value 0.014 recurrent abortion (RR-91.13, p-value 0.000, prolonged period of infertility (RR-55.16, p-value 0.000, anaemia (RR-11.37, p-value 0.003 is seen in subclinical hypothyroidism. The foetal complications seen are oligamnios (7.8%, MSAF (9.2%, foetal distress (12.1%, PROM (5.1% and FGR (10.9%. The neonates were admitted in NICU in view of NEC (1.5%, NNJ (24.1%, MAS (6.9%, TTNB (9.5% and HIE (2.9%. CONCLUSION The present study is intended to study the maternal and foetal effects of thyroid dysfunction. After the study, we concluded that there are many adverse maternal, foetal and neonatal effects in pregnancies complicated with thyroid dysfunction. In coastal area, the disease has got a high prevalence and hence there is a need for proper screening and early diagnosis. Proper treatment options are given to the patient.

Determinants and outcomes of acute transcatheter valve-in-valve therapy or embolization: a study of multiple valve implants in the U.S. PARTNER trial (Placement of AoRTic TraNscathetER Valve Trial Edwards SAPIEN Transcatheter Heart Valve).

Science.gov (United States)

Makkar, Raj R; Jilaihawi, Hasan; Chakravarty, Tarun; Fontana, Gregory P; Kapadia, Samir; Babaliaros, Vasilis; Cheng, Wen; Thourani, Vinod H; Bavaria, Joseph; Svensson, Lars; Kodali, Susheel; Shiota, Takahiro; Siegel, Robert; Tuzcu, E Murat; Xu, Ke; Hahn, Rebecca T; Herrmann, Howard C; Reisman, Mark; Whisenant, Brian; Lim, Scott; Beohar, Nirat; Mack, Michael; Teirstein, Paul; Rihal, Charanjit; Douglas, Pamela S; Blackstone, Eugene; Pichard, Augusto; Webb, John G; Leon, Martin B

2013-07-30

This study investigated the determinants and outcomes of acute insertion of a second transcatheter prosthetic valve (TV) within the first (TV-in-TV) or transcatheter valve embolization (TVE) after transcatheter aortic valve replacement (TAVR). TAVR failure can occur with both TV-in-TV and TVE as a consequence of TAVR malpositioning. Only case reports and limited series pertaining to these complications have been reported to date. Patients undergoing TAVR in the PARTNER (Placement of AoRTic TraNscathetER Valve Trial Edwards SAPIEN Transcatheter Heart Valve) randomized trial (cohorts A and B) and accompanying registries were studied. Data were dichotomized for those with and without TV-in-TV or TVE, respectively. From a total of 2,554 consecutive patients, 63 (2.47%) underwent TV-in-TV and 26 (1.01%) TVE. The indication for TV-in-TV was significant aortic regurgitation in most patients, often due not only to malpositioning but also to leaflet dysfunction. Despite similar aortic valve function on follow-up echoes, TV-in-TV was an independent predictor of 1-year cardiovascular mortality (hazard ratio [HR]: 1.86, 95% confidence interval [CI]: 1.03 to 3.38, p = 0.041), with a nonsignificant trend toward greater all-cause mortality (HR: 1.43, 95% CI: 0.88 to 2.33, p = 0.15). Technical and anatomical reasons accounted for most cases of TVE. A multivariable analysis found TVE to be an independent predictor of 1-year mortality (HR: 2.68, 95% CI: 1.34 to 5.36, p = 0.0055) but not cardiovascular mortality (HR: 1.30, 95% CI: 0.48 to 3.52, p = 0.60). Acute TV-in-TV and TVE are serious sequelae of TAVR, often resulting in multiple valve implants. They carry an excess of mortality and are caused by anatomic and technical factors, which may be avoidable with judicious procedural planning. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Echocardiographic Assessment of Heart Valve Prostheses

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Sordelli, Chiara; Severino, Sergio; Ascione, Luigi; Coppolino, Pasquale; Caso, Pio

2014-01-01

Patients submitted to valve replacement with mechanical or biological prosthesis, may present symptoms related either to valvular malfunction or ventricular dysfunction from other causes. Because a clinical examination is not sufficient to evaluate a prosthetic valve, several diagnostic methods have been proposed to assess the functional status of a prosthetic valve. This review provides an overview of echocardiographic and Doppler techniques useful in evaluation of prosthetic heart valves. Compared to native valves, echocardiographic evaluation of prosthetic valves is certainly more complex, both for the examination and the interpretation. Echocardiography also allows discriminating between intra- and/or peri-prosthetic regurgitation, present in the majority of mechanical valves. Transthoracic echocardiography (TTE) requires different angles of the probe with unconventional views. Transesophageal echocardiography (TEE) is the method of choice in presence of technical difficulties. Three-dimensional (3D)-TEE seems to be superior to 2D-TEE, especially in the assessment of paravalvular leak regurgitation (PVL) that it provides improved localization and analysis of the PVL size and shape. PMID:28465917

Platypnea-Orthodeoxia Syndrome after Transcatheter Aortic Valve Implantation

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Andrew K. Roy

2016-01-01

Full Text Available Progressive dyspnea and hypoxaemia in the subacute phase after transcatheter aortic valve implantation (TAVI are uncommon and warrant immediate assessment of valve and prosthesis leaflet function to exclude thrombosis, as well as investigation for other causes related to the procedure, such as left ventricular dysfunction, pulmonary embolism, and respiratory sepsis. In this case, we report the observation of a patient presenting two weeks after TAVI with arterial hypoxaemia in an upright position, relieved by lying flat, and coupled with an intracardiac shunt detected on echocardiography in the absence of pulmonary hypertension, raising the suspicion of Platypnea-Orthodeoxia Syndrome (POS. Invasive intracardiac haemodynamic assessment showed a significant right-to-left shunt (Qp/Qs = 0.74, which confirmed the diagnosis, with subsequent closure of the intracardiac defect resulting in immediate relief of symptoms and hypoxaemia. To our knowledge, this is the first reported case of an interatrial defect and shunt causing Platypnea-Orthodeoxia Syndrome after transcatheter aortic valve implantation, resolved by percutaneous device closure.

Aorta-atria-septum combined incision for aortic valve re-replacement

Science.gov (United States)

Xu, Yiwei; Ye, Xiaofeng; Li, Zhaolong

2018-01-01

This case report illustrates a patient who underwent supra-annular mechanical aortic valve replacement then suffered from prosthesis dysfunction, increasing pressure gradient with aortic valve. She was successfully underwent aortic valve re-replacement, sub-annular pannus removing and aortic annulus enlargement procedures through combined cardiac incision passing through aortic root, right atrium (RA), and upper atrial septum. This incision provides optimal visual operative field and simplifies dissection. PMID:29850170

Intermittent acute aortic valve regurgitation: A case report of a prosthetic valve dysfunction

NARCIS (Netherlands)

S.E. Karagiannis (Stefanos); G. Karatasakis (George); K. Spargias (Konstantinos); L. Louka; D. Poldermans (Don); D.V. Cokkinos (Dennis)

2008-01-01

textabstractComplications of any mechanical prosthesis include thrombus or pannus formation. In our case report we demonstrate that prosthetic aortic valve regurgitation due to pannus formation may be intermittent and non-cyclic in pattern and therefore not obvious at the time of original clinical

Presence of gingivitis and periodontitis significantly increases hospital charges in patients undergoing heart valve surgery.

Science.gov (United States)

Allareddy, Veerasathpurush; Elangovan, Satheesh; Rampa, Sankeerth; Shin, Kyungsup; Nalliah, Romesh P; Allareddy, Veerajalandhar

2015-01-01

To examine the prevalence and impact of gingivitis and periodontitis in patients having heart valve surgical procedures. Nationwide Inpatient Sample for the years 2004-2010 was used. All patients who had heart valve surgical procedures were selected. Prevalence of gingivitis/periodontitis was examined in these patients. Impact of gingivitis/periodontitis on hospital charges, length of stay, and infectious complications was examined. 596,190 patients had heart valve surgical procedures. Gingivitis/periodontitis was present in 0.2 percent. Outcomes included: median hospital charges ($175,418 with gingivitis/ periodontitis versus $149,353 without gingivitis/periodontitis) and median length of stay (14 days with gingivitis/periodontitis versus 8 days without gingivitis/periodontitis). After adjusting for the effects of patient- and hospital-level confounding factors, hospital charges and length of stay were significantly higher (p gingivitis/periodontitis compared to their counterparts. Further, patients with gingivitis/periodontitis had significantly higher odds for having bacterial infections (OR = 3.41, 95% CI = 2.33-4.98, p gingivitis/periodontitis. Presence of gingivitis and periodontitis is associated with higher risk for bacterial infections and significant hospital resource utilization.

Durability of Aortic Valve Cusp Repair With and Without Annular Support.

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Zeeshan, Ahmad; Idrees, Jay J; Johnston, Douglas R; Rajeswaran, Jeevanantham; Roselli, Eric E; Soltesz, Edward G; Gillinov, A Marc; Griffin, Brian; Grimm, Richard; Hammer, Donald F; Pettersson, Gösta B; Blackstone, Eugene H; Sabik, Joseph F; Svensson, Lars G

2018-03-01

To determine the value of aortic valve repair rather than replacement for valve dysfunction, we assessed late outcomes of various repair techniques in the contemporary era. From January 2001 to January 2011, aortic valve repair was planned in 1,124 patients. Techniques involved commissural figure-of-8 suspension sutures (n = 63 [6.2%]), cusp repair with commissuroplasty (n = 481 [48%]), debridement (n = 174 [17%]), free-margin plication (n = 271 [27%]) or resection (n = 75) or both, or annulus repair with resuspension (n = 230 [23%]), root reimplantation (n = 252 [25%]), or remodeling (n = 35 [3.5%]). Planned repair was aborted for replacement in 115 patients (10%); risk factors included greater severity of aortic regurgitation (AR; p = 0.0002) and valve calcification (p < 0.0001). In-hospital outcomes for the remaining 1,009 patients included death (12 [1.2%]), stroke (13 [1.3%]), and reoperation for valve dysfunction (14 [1.4%]). Freedom from aortic valve reoperation at 1, 5, and 10 years was 97%, 93%, and 90%, respectively. Figure-of-8 suspension sutures, valve resuspension, and root repair and replacement were least likely to require reoperation; cusp repair with commissural sutures, plication, and commissuroplasty was most likely (p < 0.05). Survival at 1, 5, and 10 years was 96%, 92%, and 83%. Immediate postoperative AR grade was none-mild (94%), moderate (5%), and severe (1%). At 10 years after repair, AR grade was none (20%), mild (33%), moderate (26%), and severe (21%). Patients undergoing root procedures were less likely to have higher-grade postoperative AR (p < 0.0001). Valve repair is effective and durable for treating aortic valve dysfunction. Greater severity of AR preoperatively is associated with higher likelihood of repair failure. Commissural figure-of-8 suspension sutures and repair with annular support have the best long-term durability. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights

Anesthetic management for combined mitral valve replacement and aortic valve repair in a patient with osteogenesis imperfecta

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Huang Jiapeng

2011-01-01

Full Text Available Osteogenesis imperfecta is a rare disorder of connective tissues and presents multiple challenges, including difficult airway, hyperthermia, coagulopathy and respiratory dysfunction, for anesthesiologists, especially during cardiac surgery. We present anesthetic management of a patient with osteogenesis impertecta during double valve surgery. Dexmedetomidine infusion minimized the risks of malignant hyperthermia. Glidescope and in-line stabilization facilitated endotracheal intubation and protected his oral structures and cervical spine. Transesophageal echocardiography (TEE diagnosed a flail A3 segment and redundant left coronary cusp causing mitral and aortic regurgitation. The mitral valve was replaced and the aortic valve repaired. Coagulopathy was corrected according to comprehensive coagulation analysis. Glidescope, dexmedetomidine, coagulation analysis and TEE could facilitate anesthetic management in these patients.

The dilemma of complicated shunt valves: How to identify patients with posthemorrhagic hydrocephalus after aneurysmatic subarachnoid hemorrhage who will benefit from a simple valve?

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Christian von der Brelie

2016-01-01

Full Text Available Background: Sophisticated shunt valves provide the possibility of pressure adjustment and antisiphon control but have a higher probability of valve dysfunction especially in a posthemorrhagic setting. The aim of the present study is to analyze the clinical outcome of patients with shunt dependent posthemorrhagic hydrocephalus after aneurysmatic subarachnoid hemorrhage (SAH in order to identify patients who would benefit from a simple differential pressure valve. Methods: From 2000 to 2013, 547 patients with aneurysmatic SAH were treated at our institution, 114 underwent ventricular shunt placement (21.1%. 47 patients with available pre- and post-operative computed tomography scans, and an available follow-up of minimum 6 months were included. In order to measure the survival time which a nonprogrammable differential pressure valve would have had in an individual patient we defined the initial equalized shunt survival time (IESS. IESS is the time until surgical revisions of fixed differential pressure or flow-regulated valves for the treatment of over- or under-drainage as well as re-programming of adjustable valves due to over- or under-drainage. Results: Twenty patients were treated with fixed differential pressure valves, 15 patients were treated with flow-regulated valves, and 12 underwent ventriculoperitoneal (VP shunt placement with differential pressure valves assisted by a gravitational unit. Patients who reacted with remarkable changes of the ventricular width after the insertion of external ventricular drainage (EVD, before shunt placement, showed a significantly longer IESS. Conclusions: Decline of the ventricular width after EVD placement was a predictor for successful VP shunt therapy in the later course of disease. Possibly, this could allow identifying patients who benefit from a simple differential pressure valve or a flow-regulated valve, and thus could possibly avoid valve-associated complications of a programmable valve in the

Echocardiographic pattern and severity of valve dysfunction in ...

African Journals Online (AJOL)

Background: Rheumatic heart disease (RHD) is the commonest acquired heart disease in children worldwide but in Uganda, data is scarce regarding its morbidity and mortality. The disease has a progressive course and patients usually require valve repair/replacement in the future. Objectives:To describe the frequency of ...

Utilization of a pressure sensor guidewire to measure bileaflet mechanical valve gradients: hemodynamic and echocardiographic sequelae.

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Doorey, Andrew J; Gakhal, Mandip; Pasquale, Michael J

2006-04-01

Suspected prosthetic valve dysfunction is a difficult clinical problem, because of the high risk of repeat valvular surgery. Echocardiographic measurements of prosthetic valvular dysfunction can be misleading, especially with bileaflet valves. Direct measurement of trans-valvular gradients is problematic because of potentially serious catheter entrapment issues. We report a case in which a high-fidelity pressure sensor angioplasty guidewire was used to cross prosthetic mitral and aortic valves in a patient, with hemodynamic and echocardiographic assessment. This technique was safe and effective, refuting the inaccurate non-invasive tests that over-estimated the aortic valvular gradient.

Prediction of thrombus-related mechanical prosthetic valve dysfunction using transesophageal echocardiography

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Lin, S. S.; Tiong, I. Y.; Asher, C. R.; Murphy, M. T.; Thomas, J. D.; Griffin, B. P.

2000-01-01

Identification of thrombus-related mechanical prosthetic valve dysfunction (MPVD) has important therapeutic implications. We sought to develop an algorithm, combining clinical and echocardiographic parameters, for prediction of thrombus-related MPVD in a series of 53 patients (24 men, age 52 +/- 16 years) who had intraoperative diagnosis of thrombus or pannus from 1992 to 1997. Clinical and echocardiographic parameters were analyzed to identify predictors of thrombus and pannus. Prevalence of thrombus and diagnostic yields relative to the number of predictors were determined. There were 22 patients with thrombus, 19 patients with pannus, and 12 patients with both. Forty-two of 53 masses were visualized using transesophageal echocardiography (TEE), including 29 of 34 thrombi or both thrombi and panni and 13 of 19 isolated panni. Predictors of thrombus or mixed presentation include mobile mass (p = 0.009), attachment to occluder (p = 0.02), elevated gradients (p = 0.04), and an international normalized ratio of or = 1 predictor. The prevalence of thrombus in the presence of or = 3 predictors is 14%, 69%, and 91%, respectively. Thus, TEE is sensitive in the identification of abnormal mass in the setting of MPVD. An algorithm based on clinical and transesophageal echocardiographic predictors may be useful to estimate the likelihood of thrombus in the setting of MPVD. In the presence of > or = 3 predictors, the probability of thrombus is high.

Inter-ethnic differences in valve morphology, valvular dysfunction, and aortopathy between Asian and European patients with bicuspid aortic valve.

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Kong, William K F; Regeer, Madelien V; Poh, Kian K; Yip, James W; van Rosendael, Philippe J; Yeo, Tiong C; Tay, Edgar; Kamperidis, Vasileios; van der Velde, Enno T; Mertens, Bart; Ajmone Marsan, Nina; Delgado, Victoria; Bax, Jeroen J

2018-04-14

, and valve function, the dimensions of the aortic annulus [mean difference 1.17 mm/m2, 95% confidence interval (CI) 0.96-1.39], SOV (mean difference 1.86 mm/m2, 95% CI 1.47-2.24), STJ (mean difference 0.52 mm/m2, 95% CI 0.14-0.90) and AA (mean difference 1.05 mm/m2, 95% CI 0.57-1.52) were significantly larger among Asians compared with Europeans. This large multicentre registry reports for the first time that Asians with BAV showed more frequently type 1 BAV (with fusion between right and non-coronary cusp) and have larger aortic dimensions than Europeans. These findings have important implications for prosthesis type and size selection for TAVR.

Tricuspid Valve Dysfunction Following Pacemaker or Cardioverter-Defibrillator Implantation.

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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.

Resurgery for recurrent heart valve diseases

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Chong-lei REN

2017-02-01

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

Aortic Valve Replacement for Infective Endocarditis in a Renal Transplant Recipient

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Masmoudi Sayda

2000-01-01

Full Text Available Renal transplant recipients are more prone to developing infections. We report a 37-year old renal transplant recipient who developed infective endocarditis of the aortic valve, heart failure and renal allograft dysfunction. He underwent aortic valve replacement which was followed by improvement in cardiac as well as allograft function.

Impact of Aortic Valve Replacement on Left Ventricular Remodeling in Patients with Severe Aortic Stenosis and Severe Left Ventricular Dysfunction

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Abderrahmane Bakkali

2016-12-01

Full Text Available Objective: The aim of this study was to evaluate the effect of aortic valve replacement on left ventricular function and remodeling among patients with severe aortic stenosis and severe left ventricular dysfunction. Methods: In this retrospective bicentric study extended over a 15-year period, 61 consecutive patients underwent isolated AVR for severe AS associated to reduced LV function. The mean age was 58.21 ± 12.50 years and 83.60 % were men. 70.50% of patients were in class III or IV NYHA. The mean left ventricular ejection fraction (LVEF was 32.9 ± 5.6.The mean LVEDD and LVESD were respectively 63.6 ± 9.2 and 50.2 ± 8.8 mm. The mean calculated logistic EuroScore was 12.2 ±4.5. Results: The hospital mortality was 11.5%. Morbidity was marked mainly by low output syndrome in 40.8% of cases. After a median follow-up of 38 months we have recorded 3 deaths. Almost all survivors were in class I and II of NYHA. The mean LV end-diastolic and end-systolic diameters decreased significantly at late postoperative stage. The mean LV ejection fraction increased significantly from 32.9 ± 5.6 to 38.2 ± 9.3 and to 50.3 ± 9.6 in early and late postoperative stages, respectively. Multivariate linear regression analysis found that increased early postoperative LVEF (β= 0.44, 95% CI [0.14; 0.75], p=0.006 and low mean transprosthesis gradient (β=-0.72, 95% CI [-1.42; -0.02], p= 0.04 were the independent predictors of left ventricular systolic function recovery. Conclusion: Patients with aortic valve stenosis and impaired LV systolic function benefited from AVR as regard improvement of LV function parameters and regression of the LV diameters .This improvement depends mainly on early postoperative LVEF and mean transprosthesis gradient.

Stent fracture, valve dysfunction, and right ventricular outflow tract reintervention after transcatheter pulmonary valve implantation: patient-related and procedural risk factors in the US Melody Valve Trial.

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McElhinney, Doff B; Cheatham, John P; Jones, Thomas K; Lock, James E; Vincent, Julie A; Zahn, Evan M; Hellenbrand, William E

2011-12-01

Among patients undergoing transcatheter pulmonary valve (TPV) replacement with the Melody valve, risk factors for Melody stent fracture (MSF) and right ventricular outflow tract (RVOT) reintervention have not been well defined. From January 2007 to January 2010, 150 patients (median age, 19 years) underwent TPV implantation in the Melody valve Investigational Device Exemption trial. Existing conduit stents from a prior catheterization were present in 37 patients (25%, fractured in 12); 1 or more new prestents were placed at the TPV implant catheterization in 51 patients. During follow-up (median, 30 months), MSF was diagnosed in 39 patients. Freedom from a diagnosis of MSF was 77±4% at 14 months (after the 1-year evaluation window) and 60±9% at 39 months (3-year window). On multivariable analysis, implant within an existing stent, new prestent, or bioprosthetic valve (combined variable) was associated with longer freedom from MSF (Pbioprosthetic valve was associated with lower risk of MSF and reintervention.

Cardiac valve evaluation and adipokine levels in obese women treated with sibutramine.

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Saraç, Sefa; Saraç, Fulden

2010-06-01

The aims of present study were 1) to evaluate cardiac valve characteristics, 2) to determine the plasma concentrations of fibrinogen, high sensitivity C-reactive protein (hsCRP), adiponectin, and tumor necrosis factor-alpha (TNF-alpha) in the obese women before and after 19 months sibutramine treatment in the obese women. Sixty obese women were enrolled in this prospective, randomized study. Thirty women received 10 mg once daily dose of sibutramine for 19 months. The rest of the obese women received 15 mg once daily dose of sibutramine for 19 months. All patients were evaluated with echocardiography. Plasma levels of adiponectin and TNF-alpha were measured by enzyme-linked immunosorbent assay (ELISA) and hsCRP by immunoturbimetric assay. Student paired and unpaired t tests were used to compare the 10 mg or 15 mg dose sibutramine effects either in groups or between the groups. There were no signs of significant regurgitation or thickening of the mitral and aortic valves on echocardiographic evaluation performed after 19 months of treatment. Parameters of systolic function after 10 or 15 mg treatment were not different from pretreatment characteristics. Minimal tricuspid regurgitation was found in one (1/27) patient treated with 10 mg sibutramine after 19 months. Among obese patients treated with 15 mg sibutramine one patient (1/28) had minimal mitral valve regurgitation and 2 patients (2/28) had minimal aortic insufficiency. Stage II diastolic dysfunction in the 15 obese treated with 15 mg regressed to stage I diastolic dysfunction (50%). Stage II diastolic dysfunction in the 10 obese treated with 10 mg regressed to stage I diastolic dysfunction (33.3%). Mean levels of TNF-alpha(p=0.04), fibrinogen (p=0.03) and hsCRP (p=0.04)i decreased and adiponectin (p=0.03) levels increased in the obese treated with 10 mg sibutramine. Likewise, in the patients treated with 15 mg sibutramine, mean levels of TNF- alpha(p=0.01), fibrinogen (p= 0.02), and hsCRP (p= 0.04) decreased

Significance of lung anomalies in fetuses affected by tetralogy of Fallot with absent pulmonary valve syndrome.

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Tenisch, Estelle; Raboisson, Marie-Josée; Rypens, Françoise; Déry, Julie; Grignon, Andrée; Lapierre, Chantale

2017-11-01

Tetralogy of Fallot with absent pulmonary valve syndrome is a rare form of tetralogy of Fallot with dilatation of large pulmonary arteries. Prognosis is related to the severity of the cardiac malformation and to bronchial tree compression by dilated pulmonary arteries. This study analyses the prenatal echographic lung appearance in fetuses with tetralogy of Fallot with absent pulmonary valve and discusses its significance. We carried out a retrospective review of fetal and postnatal files of nine fetuses diagnosed with tetralogy of Fallot with absent pulmonary valve syndrome in our institution. Correlations of prenatal ultrasound and cardiac imaging findings were obtained with outcome. Abnormal heterogeneous fetal lung echogenicity was detected in eight cases out of nine, always associated with significant lobar arterial dilatation. This aspect was well correlated with postnatal imaging and outcome in the four neonatal cases. The only fetus with normal lung echogenicity also had lower degree of pulmonary artery dilatation in the series. This study demonstrates that a heterogeneous ultrasound appearance of the fetal lungs can be detected in utero in the most severe cases. This aspect suggests an already significant compression of the fetal bronchial tree by the dilated arteries that may have prognostic implications.

Defect in mitochondrial functions in damaged human mitral valve

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Shinde, Santosh; Kumar, Pawan; Mishra, Kaushala; Patil, Neela

2006-01-01

Mitochondrial diseases are a heterogeneous group of disorders in which a primary mitochondrial dysfunction is proven by morphological, biochemical, and genetic examinations. The mitral valve has important function in the regulation of blood flow from one chamber to another. Often, the mitral valve becomes abnormal with age, in Rheumatic fever or it is abnormal from birth (Congenital) or it can be destroyed by infection i.e. bacterial endocarditis and needs replacement. Myocardial function dep...

Acute Mitral Valve Dysfunction Due to Escape of Prosthetic Mechanical Leaflet and Peripheral Leaftlet Embolization.

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Calik, Eyup Serhat; Limandal, Husnu Kamil; Arslan, Umit; Tort, Mehmet; Yildiz, Ziya; Bayram, Ednan; Dag, Ozgur; Kaygin, Mehmet Ali; Erkut, Bilgehan

2015-12-14

Leaflet escape of prosthetic valve is rare but potentially life threatening. Early diagnosis is essential on account of avoiding mortality, and emergency surgical correction is compulsory. This complication has previously been reported for both monoleaflet and bileaflet valve models. A 30-year-old man who had undergone mitral valve replacement with a bileaflet valve 8 years prior at another center was admitted with acute-onset with cardiogenic shock as an emergency case. Transthoracic echocardiograms showed acute-starting severe mitral regurgitation associated with prosthetic mitral valve. There was a suspicious finding of a single prosthetic mitral leaflet. But the problem related with the valve wasn't specifically determined. The patient underwent emergent surgery for replacement of the damaged prosthetic valves immediately. There was no tissue impingement and thrombosis, one of the two leaflets was absent, and there were no signs of endocarditis or pannus formation in the prosthetic valve. The missing leaflet could not be found within the cardiac cavity. The abdominal fluoroscopic study and plain radiography were unable to detect the escaped leaflet during surgery. The damaged valve was removed and a replacement 29 mm bileaflet mechanical valve was inserted by right lateral thoracotomy. After post-operative week one, the abdominal computed tomography scan and the ultrasound showed the escaped leaflet in the left femoral artery. Fifteen days after the surgery the escaped leaflet was removed safely from the left femoral artery and the patient made a complete recovery. The escaped leaflet showed a fracture of one of the pivot systems caused by structural failure. Early cardiac surgery should be applied because of life-threatening problems.

Extrinsic mechanism obstructing the opening of a prosthetic mitral valve: an unusual case of suture entrapment.

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Ozkan, Mehmet; Astarcioglu, Mehmet Ali; Karakoyun, Suleyman; Balkanay, Mehmet

2012-02-01

Obstruction to a prosthetic cardiac valve is a well-recognized complication of cardiac valve replacement. Malfunction of the mobile component of a prosthetic valve to open or close correctly may occur in consequence of intrinsic or extrinsic causes (thrombus, vegetation, entrapment of left ventricular myocardium, suture entanglement, and pannus formation) that may result prosthetic valve stenosis and/or insufficiency. In the case we report a 48-year-old female with valve dysfunction occurred early after surgery, as one valve leaflet was only able to partially open due to suture entrapment. © 2011, Wiley Periodicals, Inc.

Percutaneous pulmonary valve implantation in patients with dysfunction of a "native" right ventricular outflow tract - Mid-term results.

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Georgiev, Stanimir; Tanase, Daniel; Ewert, Peter; Meierhofer, Christian; Hager, Alfred; von Ohain, Jelena Pabst; Eicken, Andreas

2018-05-01

To investigate the feasibility and mid-term results of percutaneous pulmonary valve implantation (PPVI) in patients with conduit free or "native" right ventricular outflow tracts (RVOT). We identified all 18 patients with conduit free or "native" right ventricular outflow tract, who were treated with percutaneous pulmonary valve implantation (PPVI) in our institution. They were divided into two groups - these in whom the central pulmonary artery was used as an anchoring point for the preparation of the landing zone (n=10) for PPVI and these, in whom a pulmonary artery branch was used for this purpose (n=8). PPVI was performed successfully in all patients with significant immediate RVOT gradient and pulmonary regurgitation grade reduction. Four patients had insignificant paravalvular regurgitation. In one patient the valve was explanted after 4months because of bacterial endocarditis. A follow-up of 19 (4-60) months showed sustained good function of the other implanted valves. The MRI indexed right ventricular end diastolic volume significantly decreased from 108(54-174) ml/m 2 before the procedure to 76(60-126) ml/m 2 six months after PPVI, p=0.01. PPVI is feasible with good mid-term results in selected patients with a "native" RVOT without a previously implanted conduit. Creating a stable landing zone with a diameter less than the largest available valve (currently 29mm) is crucial for the technical success of the procedure. Further studies and the development of new devices could widen the indications for this novel treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Pathophysiology of shunt dysfunction in shunt treated hydrocephalus

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Blegvad, C.; Skjolding, A D; Broholm, H

2013-01-01

We hypothesized that shunt dysfunction in the ventricular catheter and the shunt valve is caused by different cellular responses. We also hypothesized that the cellular responses depend on different pathophysiological mechanisms....

Methods of estimation of mitral valve regurgitation for the cardiac surgeon

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Baikoussis Nikolaos G

2009-07-01

Full Text Available Abstract Mitral valve regurgitation is a relatively common and important heart valve lesion in clinical practice and adequate assessment is fundamental to decision on management, repair or replacement. Disease localised to the posterior mitral valve leaflet or focal involvement of the anterior mitral valve leaflet is most amenable to mitral valve repair, whereas patients with extensive involvement of the anterior leaflet or incomplete closure of the valve are more suitable for valve replacement. Echocardiography is the recognized investigation of choice for heart valve disease evaluation and assessment. However, the technique is depended on operator experience and on patient's hemodynamic profile, and may not always give optimal diagnostic views of mitral valve dysfunction. Cardiac catheterization is related to common complications of an interventional procedure and needs a hemodynamic laboratory. Cardiac magnetic resonance (MRI seems to be a useful tool which gives details about mitral valve anatomy, precise point of valve damage, as well as the quantity of regurgitation. Finally, despite of its higher cost, cardiac MRI using cine images with optimized spatial and temporal resolution can also resolve mitral valve leaflet structural motion, and can reliably estimate the grade of regurgitation.

[Late complications following Björk-Shiley and St. Jude Medical heart valve replacement].

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Horstkotte, D; Körfer, R; Budde, T; Haerten, K; Schulte, H D; Bircks, W; Loogen, F

1983-05-01

Valve-related complications after Björk-Shiley mitral (n = 475), aortic (n = 424), or mitral-aortic implantation (n = 119) were compared to complications after St. Jude mitral (n = 173), aortic (n = 152), and St. Jude mitral and aortic (n = 63) replacements. The 1,018 consecutive patients with Björk-Shiley valves had been operated upon between 1974 and 1982, those with St. Jude valves between 1978 and 1982. All patients were placed on anticoagulant therapy with phenprocoumon early after operation and no significant intergroup differences in the effectiveness of the anticoagulant therapy were found. At a comparable follow-up time of approximately 23 months, 24 major thromboembolic episodes were observed after Björk-Shiley mitral (BSM) and 3 after St. Jude mitral valve implantation (SJM), corresponding to a thromboembolic rate of 2.82/100 patient years with BSM and 0.93/100 patient years with SJM. After aortic valve replacements, 1.93 events in 100 patient years occurred after Björk-Shiley aortic (BSA) and 0.73 after St. Jude aortic implantation (SJA). In patients with double valve replacements, these rates were 3.2 (BSM + BSA) and 0.88 (SJM + SJA), respectively. The cerebral vessels were involved in 52% and the arteries of the extremities in 22% of these major events. Six Björk-Shiley prostheses had to be replaced because of valve thrombosis. The overall incidence of severe hemorrhagic complications was 2.94/100 patient years in BSM and 1.79 in SJM. After aortic valve replacement, we found rates of 1.80/100 patient years (BSA) and 2.57/100 patient years (SJA), respectively. Intravascular hemolysis no longer seems to be a significant clinical problem. However, indications of red cell damage after heart valve replacement were significantly greater in patients with perivalvular leakage, valve thrombosis, or dysfunction than in those with normally functioning prostheses. Reoperations were necessary because of valve thrombosis (0.46%), perivalvular leakage (2

Recurrent acute pulmonary oedema after aortic and mitral valve surgery due to trachea malacia and obstructive sleep apnoea syndrome

NARCIS (Netherlands)

Sankatsing, S. U. C.; Hanselaar, W. E. J. J.; van Steenwijk, R. P.; Van der Sloot, J. A. P.; Broekhuis, E.; Kok, W. E. M.

2008-01-01

In this report we describe a patient with recurrent episodes of acute pulmonary oedema after aortic and mitral valve surgery. The first episode of pulmonary oedema was caused by mitral valve dysfunction. The second episode of pulmonary oedema was not clearly associated with a mitral valve problem,

Effects of right ventricular morphology and function on outcomes of patients with degenerative mitral valve disease.

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Ye, Ying; Desai, Ravi; Vargas Abello, Lina M; Rajeswaran, Jeevanantham; Klein, Allan L; Blackstone, Eugene H; Pettersson, Gösta B

2014-11-01

The study objective was to investigate whether, in patients undergoing surgery for degenerative mitral valve disease, associated right ventricular remodeling and dysfunction are stronger determinants of preoperative organ dysfunction and prognosis than functional tricuspid regurgitation. From January 2001 to January 2011, 4197 patients underwent primary mitral valve surgery for degenerative valve disease at Cleveland Clinic. Using a quasi-experimental enriched study design, 781 patients were randomly selected within each grade of functional tricuspid regurgitation. Renal function was assessed by glomerular filtration rate and blood urea nitrogen, and hepatic function was assessed by Model for End-stage Liver Disease (MELD) score. Preoperative and postoperative right ventricular morphology and function were measured de novo on stored echocardiographic images. To assess survival, 3471 patient-years of follow-up data were available for analysis. Several preoperative right ventricular variables, but not functional tricuspid regurgitation grade (P>.05), were associated with preoperative renal and hepatic dysfunction, but neither was associated with early mortality (.2), was among the risk factors for later mortality. Postoperative unadjusted right ventricular function, but not functional tricuspid regurgitation grade (P≥.2), was associated with both early (P=.04) and later (P=.01) mortality, but in multivariable analysis appeared to be a surrogate for worse preoperative condition. Together with patient comorbidities and operative factors, right ventricular morphology and function are associated more strongly with preoperative organ dysfunction and prognosis than is functional tricuspid regurgitation severity in patients undergoing surgery for degenerative mitral valve disease. Our previous study showed that tricuspid valve repair remains the most effective treatment to improve right ventricular function. Copyright © 2014 The American Association for Thoracic Surgery

Mitral valve repair: an echocardiographic review: Part 2.

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Maslow, Andrew

2015-04-01

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

Evaluation of p53 Polymorphism in Patients with Pannus-Derived Prosthetic Dysfunction.

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Gursoy, Mustafa Ozan; Karakoyun, Suleyman; Kalcik, Macit; Yesin, Mahmut; Gunduz, Sabahattin; Astarcioğlu, Mehmet Ali; Oğuz, Ali Emrah; Ozkan, Mehmet

2015-09-01

Prosthetic valve dysfunction (PVD) due to pannus formation is considered to occur due to a bioreaction to prosthetic material. The p53 gene plays a critical role in apoptosis and cell proliferation. p53 Arg72Pro polymorphism has been found to be associated with coronary stent restenosis, but has not yet been studied in prosthetic heart valve dysfunction. The study aim was to evaluate the association between pannus-derived PVD and p53 G72C(Arg72Pro) polymorphism. This single-center, prospective study included 25 patients (20 females, five males; mean age 45.6 +/- 12.5 years; group 1) who underwent redo valve surgery due to PVD, and 49 age- and gender-matched control patients (44 females, five males; mean age 47.3 +/- 12.2 years; group 2) with normofunctional prostheses. The prostheses were examined using transthoracic and transesophageal echocardiography. Analyses of p53 G72C(Arg72Pro) polymorphism were performed using Roche LightCyler 2.0 Real-time polymerase chain reaction. The most common location of replaced valves was the mitral position in both groups (88% and 89.8%, respectively). In group 1, normal alleles (GG) were observed in 12 patients (48%), while one patient (4%) showed a homozygous mutation (GC) and 12 patients (48%) showed a heterozygous mutation (CC). In group 2, 21 patients (42.9%) had normal alleles (GG), while four (8.2%) had a homozygous mutation (CC) and 24 (48.9%) had a heterozygous mutation (GC). No significant difference was observed between the groups with regards to p53 Arg72Pro polymorphism (p = 0.769). In patients with prosthetic valves, the underlying mechanism behind pannus formation is unrelated to p53 Arg72Pro polymorphism.

Prosthetic Valve Endocarditis - Successful Management With Antimicrobial Treatment

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Ashokan Nambiar C

2015-07-01

Full Text Available Middle aged male was admitted with high fever, rigor and chills of 2 days duration. He was seen in the clinic two years back for syncope. He gave history of Mitral (Starr-Edward and Aortic (Medtronic valve replacement ten years earlier from another center and was on regular anticoagulation with dose-adjusted acenocoumarol. On evaluation he had normal prosthetic valve function by trans-thoracic echo, but Holter monitoring showed Paroxysmal Atrial Fibrillation. He had mild wall motion abnormalities and left ventricular dysfunction suggestive of coronary artery disease also and was put on additional Metoprolol.

Study of prognostic significance of antenatal ultrasonography and renin angiotensin system activation in predicting disease severity in posterior urethral valves

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Divya Bhadoo

2015-01-01

Full Text Available Aims: Study on prognostic significance of antenatal ultrasonography and renin angiotensin system activation in predicting disease severity in posterior urethral valves. Materials and Methods: Antenatally diagnosed hydronephrosis patients were included. Postnatally, they were divided into two groups, posterior urethral valve (PUV and non-PUV. The studied parameters were: Gestational age at detection, surgical intervention, ultrasound findings, cord blood and follow up plasma renin activity (PRA values, vesico-ureteric reflux (VUR, renal scars, and glomerular filtration rate (GFR. Results: A total of 25 patients were included, 10 PUV and 15 non-PUV. All infants with PUV underwent primary valve incision. GFR was less than 60 ml/min/1.73 m 2 body surface area in 4 patients at last follow-up. Keyhole sign, oligoamnios, absent bladder cycling, and cortical cysts were not consistent findings on antenatal ultrasound in PUV. Cord blood PRA was significantly higher (P < 0.0001 in PUV compared to non-PUV patients. Gestational age at detection of hydronephrosis, cortical cysts, bladder wall thickness, and amniotic fluid index were not significantly correlated with GFR while PRA could differentiate between poor and better prognosis cases with PUV. Conclusions: Ultrasound was neither uniformly useful in diagnosing PUV antenatally, nor differentiating it from cases with non-PUV hydronephrosis. In congenital hydronephrosis, cord blood PRA was significantly higher in cases with PUV compared to non-PUV cases and fell significantly after valve ablation. Cord blood PRA could distinguish between poor and better prognosis cases with PUV.

Mitral valve surgery in the adult Marfan syndrome patient.

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Bhudia, Sunil K; Troughton, Richard; Lam, Buu-Khanh; Rajeswaran, Jeevanantham; Mills, William R; Gillinov, A Marc; Griffin, Brian P; Blackstone, Eugene H; Lytle, Bruce W; Svensson, Lars G

2006-03-01

Because mitral valve dysfunction in adults with Marfan syndrome is poorly characterized, this study compares mitral valve pathophysiology and morphology with that of myxomatous mitral disease, documents types of mitral valve operations, and assesses long-term survival and durability of mitral valve surgery in Marfan patients. From May 1975 to June 2000, 27 adults with Marfan syndrome underwent mitral valve surgery. Their valve pathophysiology and morphology was compared with that of 119 patients with myxomatous mitral disease undergoing surgery from September 1995 to March 1999. Survival and repair durability were assessed at follow-up. Compared with myxomatous disease patients, Marfan patients had less posterior leaflet prolapse (44% versus 70%, p = 0.01), more bileaflet (44% versus 28%, p = 0.09) and anterior leaflet prolapse (11% versus 3%, p = 0.07), and presented earlier for surgery (age 41 +/- 12 years versus 57 +/- 13, p Marfan patients had longer and thinner leaflets. Mitral valve repair was performed less frequently in Marfan (16 of 27, 59%) than myxomatous disease patients (112 of 119, 94%). There were no hospital deaths; at 10 years, survival was 80% and freedom from reoperation 96%, with only 1 reoperation among the 16 repairs. Mitral valve pathophysiology and morphology differ between Marfan and myxomatous mitral valve diseases. Valve repair in Marfan patients is durable and gives acceptable long-term results, even in adults who present with advanced mitral valve pathology. With increasing use of the modified David reimplantation operation and sparing of the aortic valve, mitral valve repair is a greater imperative, particularly since we have not had to reoperate on any Marfan patients with reimplantations.

Measurement of opening and closing angles of aortic valve prostheses in vivo using dual-source computed tomography: Comparison with those of manufacturers' in 10 different types

International Nuclear Information System (INIS)

Suh, Young Joo; Kim, Young Jin; Hong, Yoo Jin; Lee, Hye Jeong; Hur, Jin; Im, Dong Jin; Kim, Yun Jung; Choi, Byoung Wook

2015-01-01

The aims of this study were to compare opening and closing angles of normally functioning mechanical aortic valves measured on dual-source computed tomography (CT) with the manufacturers' values and to compare CT-measured opening angles according to valve function. A total of 140 patients with 10 different types of mechanical aortic valves, who underwent dual-source cardiac CT, were included. Opening and closing angles were measured on CT images. Agreement between angles in normally functioning valves and the manufacturer values was assessed using the interclass coefficient and the Bland-Altman method. CT-measured opening angles were compared between normal functioning valves and suspected dysfunctioning valves. The CT-measured opening angles of normally functioning valves and manufacturers' values showed excellent agreement for seven valve types (intraclass coefficient [ICC], 0.977; 95% confidence interval [CI], 0.962-0.987). The mean differences in opening angles between the CT measurements and the manufacturers' values were 1.2° in seven types of valves, 11.0° in On-X valves, and 15.5° in ATS valves. The manufacturers' closing angles and those measured by CT showed excellent agreement for all valve types (ICC, 0.953; 95% CI, 0.920-0.972). Among valves with suspected dysfunction, those with limitation of motion (LOM) and an increased pressure gradient (PG) had smaller opening angles than those with LOM only (p < 0.05). Dual-source cardiac CT accurately measures opening and closing angles in most types of mechanical aortic valves, compared with the manufacturers' values. Opening angles on CT differ according to the type of valve dysfunction and a decreased opening angle may suggest an elevated PG

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

Science.gov (United States)

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.

Ten-year results of the Freedom Solo stentless heart valve: excellent haemodynamics but progressive valve dysfunction in the long term.

Science.gov (United States)

Sponga, Sandro; Barbera, Mila Della; Pavoni, Daisy; Lechiancole, Andrea; Mazzaro, Enzo; Valente, Marialuisa; Nucifora, Gaetano; Thiene, Gaetano; Livi, Ugolino

2017-05-01

Freedom Solo (FS) is a pericardial stentless heart valve showing excellent haemodynamic performance at mid-term. The aim of this study was to evaluate the long-term performance of such bioprostheses. Between December 2004 and November 2009, 109 patients (31 men; mean age 76 ± 6 years) underwent aortic valve replacement with FS. Preoperatively, the mean NYHA class was 2.5 ± 0.7, the mean EuroSCORE II, 2.8 ± 2.5. Mean prosthesis size was 22.7 ± 1.9 mm; concomitant procedures were performed in 65 patients. Structural valve deterioration (SVD) was diagnosed according to the Valve Academic Research Consortium-2 definition. Two patients (1.8%) died within 30 days. Follow-up (72 ± 36 months) was 100% completed. The 1-, 5- and 10-year actuarial survival rates were 89, 73 and 42%, respectively, with 8 valve-related deaths; the actuarial freedom from SVD was 99, 93 and 76%. During 61 ± 39 months of follow-up, echocardiographic findings worsened progressively: At discharge, 3-5 and 7-9 years, the mean gradient was 8 ± 4, 12 ± 11 and 19 ± 19 mmHg ( P  < 0.01); the indexed effective orifice area was 1.0 ± 0.2, 0.9 ± 0.2 and 0.8 ± 0.3 cm 2 /m 2 ( P  < 0.01). Of the 13 patients who developed SVD, it was due to aortic stenosis in 11. SVD was a predictor of cardiovascular mortality at univariate analysis (HR 2.87, 1.12-7.29); 2 explanted prostheses showed massive calcium deposits with mean calcium and phosphorus contents of 234 ± 16 and 116 ± 7 mg/g dry weight, respectively. The FS bioprosthesis shows excellent mid-term clinical and haemodynamic results and offers an alternative to other valves, particularly in the case of a small aortic annulus. Worsening of FS performance was observed at late follow-up because of progressive SVD with stenosis, questioning whether it should be used in patients with a long life expectancy. © The Author 2017. Published by Oxford University Press on behalf of the

Treatment with pioglitazone induced significant, reversible mitral regurgitation.

Science.gov (United States)

Dorkhan, Mozhgan; Dencker, Magnus; Frid, Anders

2008-04-30

There has in recent years been great concern about possible cardiac side effects of thiazolidinediones (TZDs). We present a case-report of a 60 year-old male who developed significant mitral regurgitation during six months treatment with pioglitazone in parallel with laboratory indications of fluid retention. Echocardiography six months after discontinuation of medication showed regression of mitral regurgitation and the laboratory parameters were also normalized. It is noteworthy that six months treatment with pioglitazone could induce significant valve dysfunction, which was reversible, and this underlines the importance of carefully monitoring patients when placing them on treatment with TZDs.

Treatment with pioglitazone induced significant, reversible mitral regurgitation

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Frid Anders

2008-04-01

Full Text Available Abstract There has in recent years been great concern about possible cardiac side effects of thiazolidinediones (TZDs. We present a case-report of a 60 year-old male who developed significant mitral regurgitation during six months treatment with pioglitazone in parallel with laboratory indications of fluid retention. Echocardiography six months after discontinuation of medication showed regression of mitral regurgitation and the laboratory parameters were also normalized. It is noteworthy that six months treatment with pioglitazone could induce significant valve dysfunction, which was reversible, and this underlines the importance of carefully monitoring patients when placing them on treatment with TZDs.

Brain-natriuretic peptide and cyclic guanosine monophosphate as biomarkers of myxomatous mitral valve disease in dogs

DEFF Research Database (Denmark)

Moesgaard, Sophia Gry; Falk, Bo Torkel; Teerlink, Tom

2011-01-01

Elevations in the plasma concentrations of natriuretic peptides correlate with increased severity of myxomatous mitral valve disease (MMVD) in dogs. This study correlates the severity of MMVD with the plasma concentrations of the biomarkers N-terminal fragment of the pro-brain-natriuretic peptide...... (NT-proBNP) and its second messenger, cyclic guanosine monophosphate (cGMP). Furthermore, the l-arginine:asymmetric dimethylarginine (ADMA) ratio was measured as an index of nitric oxide availability. The study included 75 dogs sub-divided into five groups based on severity of MMVD as assessed...... by clinical examination and echocardiography. Plasma NT-proBNP and cGMP concentrations increased with increasing valve dysfunction and were significantly elevated in dogs with heart failure. The cGMP:NT-proBNP ratio decreased significantly in dogs with heart failure, suggesting the development of natriuretic...

Sex Differences in Phenotypes of Bicuspid Aortic Valve and Aortopathy: Insights From a Large Multicenter, International Registry.

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Kong, William K F; Regeer, Madelien V; Ng, Arnold C T; McCormack, Louise; Poh, Kian Keong; Yeo, Tiong Cheng; Shanks, Miriam; Parent, Sarah; Enache, Roxana; Popescu, Bogdan A; Yip, James W; Ma, Lawrence; Kamperidis, Vasileios; van der Velde, Enno T; Mertens, Bart; Ajmone Marsan, Nina; Delgado, Victoria; Bax, Jeroen J

2017-03-01

This large multicenter, international bicuspid aortic valve (BAV) registry aimed to define the sex differences in prevalence, valve morphology, dysfunction (aortic stenosis/regurgitation), aortopathy, and complications (endocarditis and aortic dissection). Demographic, clinical, and echocardiographic data at first presentation of 1992 patients with BAV (71.5% men) were retrospectively analyzed. BAV morphology and valve function were assessed; aortopathy configuration was defined as isolated dilatation of the sinus of Valsalva or sinotubular junction, isolated dilatation of the ascending aorta distal to the sinotubular junction, or diffuse dilatation of the aortic root and ascending aorta. New cases of endocarditis and aortic dissection were recorded. There were no significant sex differences regarding BAV morphology and frequency of normal valve function. When presenting with moderate/severe aortic valve dysfunction, men had more frequent aortic regurgitation than women (33.8% versus 22.2%, P <0.001), whereas women were more likely to have aortic stenosis (34.5% versus 44.1%, P <0.001). Men had more frequently isolated dilatation of the sinus of Valsalva or sinotubular junction (14.2% versus 6.7%, P <0.001) and diffuse dilatation of the aortic root and ascending aorta (16.2% versus 7.3%, P <0.001) than women. Endocarditis (4.5% versus 2.5%, P =0.037) and aortic dissections (0.5% versus 0%, P <0.001) occurred more frequently in men. Although there is a male predominance among patients with BAV, men with BAV had more frequently moderate/severe aortic regurgitation at first presentation compared with women, whereas women presented more often with moderate/severe aortic stenosis compared with men. Furthermore, men had more frequent aortopathy than women. © 2017 American Heart Association, Inc.

Effect of tricuspid regurgitation and the right heart on survival after transcatheter aortic valve replacement: insights from the Placement of Aortic Transcatheter Valves II inoperable cohort.

Science.gov (United States)

Lindman, Brian R; Maniar, Hersh S; Jaber, Wael A; Lerakis, Stamatios; Mack, Michael J; Suri, Rakesh M; Thourani, Vinod H; Babaliaros, Vasilis; Kereiakes, Dean J; Whisenant, Brian; Miller, D Craig; Tuzcu, E Murat; Svensson, Lars G; Xu, Ke; Doshi, Darshan; Leon, Martin B; Zajarias, Alan

2015-04-01

Tricuspid regurgitation (TR) and right ventricular (RV) dysfunction adversely affect outcomes in patients with heart failure or mitral valve disease, but their impact on outcomes in patients with aortic stenosis treated with transcatheter aortic valve replacement has not been well characterized. Among 542 patients with symptomatic aortic stenosis treated in the Placement of Aortic Transcatheter Valves (PARTNER) II trial (inoperable cohort) with a Sapien or Sapien XT valve via a transfemoral approach, baseline TR severity, right atrial and RV size and RV function were evaluated by echocardiography according to established guidelines. One-year mortality was 16.9%, 17.2%, 32.6%, and 61.1% for patients with no/trace (n=167), mild (n=205), moderate (n=117), and severe (n=18) TR, respectively (Pright atrial and RV enlargement were also associated with increased mortality (Pright atrial and RV enlargement, but not RV dysfunction. There was an interaction between TR and mitral regurgitation severity (P=0.04); the increased hazard of death associated with moderate/severe TR only occurred in those with no/trace/mild mitral regurgitation. In inoperable patients treated with transcatheter aortic valve replacement, moderate or severe TR and right heart enlargement are independently associated with increased 1-year mortality; however, the association between moderate or severe TR and an increased hazard of death was only found in those with minimal mitral regurgitation at baseline. These findings may improve our assessment of anticipated benefit from transcatheter aortic valve replacement and support the need for future studies on TR and the right heart, including whether concomitant treatment of TR in operable but high-risk patients with aortic stenosis is warranted. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01314313. © 2015 American Heart Association, Inc.

Sexual Dysfunction in Males: Significance of Adverse Childhood Experiences.

Science.gov (United States)

Kinzl, Johann F.; And Others

1996-01-01

A survey of 301 male college students found that occasional sexual dysfunction was frequent in young male adults, and long-lasting adverse familial relationships to attachment figures were more influential in later sexual dysfunction than were childhood sexual abuse experiences. (Author/DB)

Redo mitral valve surgery

Directory of Open Access Journals (Sweden)

Redoy Ranjan

2018-03-01

Full Text Available This study is based on the findings of a single surgeon’s practice of mitral valve replacement of 167 patients from April 2005 to June 2017 who developed symptomatic mitral restenosis after closed or open mitral commisurotomy. Both clinical and color doppler echocardiographic data of peri-operative and six months follow-up period were evaluated and compared to assess the early outcome of the redo mitral valve surgery. With male-female ratio of 1: 2.2 and after a duration of 6 to 22 years symptom free interval between the redo procedures, the selected patients with mitral valve restenosis undergone valve replacement with either mechanical valve in 62% cases and also tissue valve in 38% cases. Particular emphasis was given to separate the adhered pericardium from the heart completely to ameliorate base to apex and global contraction of the heart. Besides favorable post-operative clinical outcome, the echocardiographic findings were also encouraging as there was statistically significant increase in the mitral valve area and ejection fraction with significant decrease in the left atrial diameter, pressure gradient across the mitral valve and pulmonary artery systolic pressure. Therefore, in case of inevitable mitral restenosis after closed or open commisurotomy, mitral valve replacement is a promising treatment modality.

Pannus overgrowth after mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis.

Science.gov (United States)

Oda, Takeshi; Kato, Seiya; Tayama, Eiki; Fukunaga, Shuji; Akashi, Hidetoshi; Aoyagi, Shigeaki

2009-01-01

A Carpentier-Edwards pericardial (CEP) bioprosthesis was explanted from an 81-year-old woman due to nonstructural dysfunction 9 years after mitral valve replacement. The nonstructural dysfunction produced severe regurgitation in the mitral position. During the surgery, excessive pannus overgrowth was seen on the left ventricular side of the CEP bioprosthesis. Pannus overgrowth was prominent on one leaflet. That leaflet was stiff and shortened due to the excessive overgrowth of pannus. In this patient, the distortion of one leaflet was the main reason for transvalvular leakage of the CEP bioprosthesis in the mitral position. A new CEP bioprosthesis was implanted in the mitral position. Pathological analysis revealed fibrotic pannus with a small amount of cellular material over the leaflets of the resected CEP valve. This change was marked on the distorted leaflet.

Gasoline New Timing and Flux Adjustable Rotary Valve Design (Hereinafter: Rotary Valve

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Du huiqi

2016-01-01

Full Text Available Conventional gasoline engine with an umbrella valve control cylinder intake and exhaust, in order to achieve sealing effect, the valve is driven by the spring force; at the same time, when the cam opens the valve to overcome the spring force acting. Sealing the better, the more power consumed in the engine mechanical losses, the valve mechanism consumes about 30%, which is not a small loss! This article describes a new type of rotary valve is to significantly reduce mechanical losses, so as to achieve energy saving purposes.

Valve repair for traumatic tricuspid regurgitation.

Science.gov (United States)

Maisano, F; Lorusso, R; Sandrelli, L; Torracca, L; Coletti, G; La Canna, G; Alfieri, O

1996-01-01

The review of six cases of valve repair for traumatic tricuspid regurgitation in our institution and 74 in the literature in order to assess effective methods of treating this lesion. Tricuspid valve regurgitation is a rare complication of blunt chest trauma. Optimal treatment for this condition is still controversial ranging from long-term medical therapy to early surgical correction. We followed the cases of six consecutive patients with post-traumatic tricuspid incompetence who were successfully treated with reparative techniques. All patients were male and their ages ranged from 18 years to 42 years. Valve regurgitation was always secondary to blunt chest trauma due to motor vehicle accident. The mechanism of valve insufficiency was invariably anterior leaflet prolapse due to chordal or papillary muscle rupture associated with annular dilatation. Surgical procedures included Carpentier ring implant (5 patients), Bex posterior annuloplasty (1 patient), implant of artificial chordae (4 patients), papillary muscle reinsertion (2 patients), commissuroplasty (1 patient) and "artificial double orifice" technique (1 patient). Tricuspid insufficiency improved in all patients after the correction. No complications were recorded and all patients were asymptomatic at the follow-up. Since post-traumatic tricuspid regurgitation is effectively correctable with reparative techniques, early operation is recommended to relieve symptoms and to prevent right ventricular dysfunction.

Fracture and embolization of a Björk-Shiley disc. Fatal failure of a prosthetic mitral valve.

Science.gov (United States)

Norenberg, D D; Evans, R W; Gundersen, A E; Abellera, R M

1977-12-01

A case of fracture of the disc occluder of a Bjork-Shiley mitral prosthesis with embolization of the disc fragments to distal aorta is presented. The possibility of valve dysfunction and the diagnostic value of echocardiography should be considered whenever acute heart failure occurs in a patient with an artificial valve.

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

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S. A. Kovalev

2015-01-01

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

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

Science.gov (United States)

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

2004-03-01

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

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

Science.gov (United States)

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

2015-03-01

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

[Significance of early diagnosis of posterior urethral valves in fetus for further development - own experience].

Science.gov (United States)

Krzemień, Grażyna; Szmigielska, Agnieszka; Wawer, Zofia; Roszkowska-Blaim, Maria

2013-01-01

The incidence of posterior urethral valves is estimated to be from 3:1000 to 8:1000 and this is one of the most common causes of obstruction of urinary tract in boys. About 13-17% of children with posterior urethral valves develop end stage renal failure. We present a  6-month-old boy with late diagnosis of posterior urtehral valves. Antenatal ultrasound investigation of the urinary tract was normal. A small degree of oligohydramnios was found during delivery. At the age of six months the boy was admitted to hospital because of urinary tract infection, hypertension (130/90 mmHg) and acute kidney injury (urea - 46 mg/dL, creatinine - 1.1 mg/dL, GFR - 35.5 mL/min/1.73 m2 ). Bilateral hydronephrosis and megaureters, low-capacity bladder with hypertrophied wall were seen on ultrasound examination. Voiding cystourethrograhy revealed vesicoureteral refluxes (III/V), hypertrophy of the bladder wall with numerous diverticula and dilated posterior urethra. During urethroscopy urethral valves were resected. Increased intravesical pressure (leak point up to 305 cm H2 O) was found on urodynamic test. Renal scintigraphy (99mTc-EC) revealed decreased intake of isotope in the left kidney (5%), and the right kidney intake was 95% ERPF. The patient was qualified for left-sided nephrectomy, which was postponed because of high leak point and high risk of worsening of vesicoureteral reflux to right kidney after nephrectomy. Anticholinergic and α-blocker treatment was started. At the age of 11 months left-side nephrectomy was performed because of recurrent urinary tract infections. After 3.5-year follow-up blood pressure, physical development, kidney function tests, and urinalysis are normal. Additionally to this investigation the significance of early diagnosis including prenatal (PUV) for further development as well as further therapeutic procedure is discussed.

Novel imaging strategies for the detection of prosthetic heart valve obstruction and endocarditis

NARCIS (Netherlands)

W. Tanis (Wilco); R.P.J. Budde (Ricardo); I.A.C. van der Bilt (Ivo); B. Delemarre; G. Hoohenker; J.-K. Van Rooden; A.M. Scholtens (Asbjørn M.); J. Habets; S.A.J. Chamuleau (Steven)

2016-01-01

textabstractProsthetic heart valve (PHV) dysfunction remains difficult to recognise correctly by two-dimensional (2D) transthoracic and transoesophageal echocardiography (TTE/TEE). ECG-triggered multidetector-row computed tomography (MDCT), 18-fluorine-fluorodesoxyglucose positron emission

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

Science.gov (United States)

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 valve effective orifice area (from 1.0±0.4 to 1.8±0.6 cm 2 , P 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.

Novel imaging strategies for the detection of prosthetic heart valve obstruction and endocarditis

NARCIS (Netherlands)

Tanis, W; Budde, R P J; van der Bilt, I A C; Delemarre, B; Hoohenkerk, G; van Rooden, J-K; Scholtens, A M; Habets, J; Chamuleau, S

Prosthetic heart valve (PHV) dysfunction remains difficult to recognise correctly by two-dimensional (2D) transthoracic and transoesophageal echocardiography (TTE/TEE). ECG-triggered multidetector-row computed tomography (MDCT), 18-fluorine-fluorodesoxyglucose positron emission tomography including

Added value of cardiac computed tomography for evaluation of mechanical aortic valve: Emphasis on evaluation of pannus with surgical findings as standard reference.

Science.gov (United States)

Suh, Young Joo; Lee, Sak; Im, Dong Jin; Chang, Suyon; Hong, Yoo Jin; Lee, Hye-Jeong; Hur, Jin; Choi, Byoung Wook; Chang, Byung-Chul; Shim, Chi Young; Hong, Geu-Ru; Kim, Young Jin

2016-07-01

The added value of cardiac computed tomography (CT) with transesophageal echocardiography (TEE) for evaluating mechanical aortic valve (AV) dysfunction has not yet been investigated. The purposes of this study were to investigate the added value of cardiac CT for evaluation of mechanical AVs and diagnoses of pannus compared to TEE, with surgical findings of redo-aortic valve replacement (AVR) used as a standard reference. 25 patients who underwent redo-AVR due to mechanical AV dysfunction and cardiac CT before redo-AVR were included. The presence of pannus, encroachment ratio by pannus, and limitation of motion (LOM) were evaluated on CT. The diagnostic performance of pannus detection was compared using TEE, CT, and CT+TEE, with surgical findings as a standard reference. The added value of CT for diagnosing the cause of mechanical AV dysfunction was assessed compared to TTE+TEE. In two patients, CT analysis was not feasible due to severe metallic artifacts. On CT, pannus and LOM were found in 100% (23/23) and 60.9% (14/23). TEE identified pannus in 48.0% of patients (12/25). CT, TEE, and CT+TEE correctly identified pannus with sensitivity of 92.0%, 48.0%, and 92.0%, respectively (P=0.002 for CT vs. TEE). In 11 of 13 cases (84.6%) with inconclusive or negative TEE results for pannus, CT detected the pannus. Among 13 inconclusive cases of TTE+TEE for the cause of mechanical AV dysfunction, CT suggested 6 prosthetic valve obstruction (PVO) by pannus, 4 low-flow low-gradient PVO, and one LOM without significant PVO. Cardiac CT showed added diagnostic value with TEE in the detection of pannus as the cause of mechanical AV dysfunction. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

Science.gov (United States)

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

2014-08-01

Osteogenesis imperfecta is associated with increased prevalence of significant mitral valve regurgitation. Surgical mitral valve repair and replacement are feasible but are associated with increased risk of bleeding and dehiscence of implanted valves may occur more frequently. The present case report describes the outcomes of transcatheter mitral valve repair in a patient with osteogenesis imperfecta. A 60 year-old patient with osteogenesis imperfecta and associated symptomatic moderate to severe mitral regurgitation underwent transthoracic echocardiography which showed a nondilated left ventricle with preserved systolic function and moderate to severe mitral regurgitation. On transoesophageal echocardiography the regurgitant jet originated between the anterolateral scallops of the anterior and posterior leaflets (A1-P1). Considering the comorbidities associated with osteogenesis imperfecta the patient was accepted for transcatheter mitral valve repair using the Mitraclip device (Abbott vascular, Menlo, CA). Under fluoroscopy and 3D transoesophageal echocardiography guidance, a Mitraclip device was implanted between the anterolateral and central scallops with significant reduction of mitral regurgitation. The postoperative evolution was uneventful. At one month follow-up, transthoracic echocardiography showed a stable position of the Mitraclip device with no mitral regurgitation. Transcatheter mitral valve repair is feasible and safe in patients with osteogenesis imperfecta and associated symptomatic significant mitral regurgitation. Copyright © 2014 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Subvalvular pannus and thrombosis in a mitral valve prosthesis.

Science.gov (United States)

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

2016-01-01

A 69-year-old female underwent cardiac CT to evaluate prosthetic valve (PHV) dysfunction detected on echocardiography. A CT coronal and en face views of the mitral annular plane showed a low-density, mass-like lesion on the left atrial side of the PHV and a high-density, plate-like lesion on the left ventricular side of PHV. A repeat of the mitral valve replacement was performed, and preoperative CT findings of both the thrombus on the left atrial side and pannus formation on the LV side were confirmed in the operative findings. Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Radiotherapy-induced aortic valve disease associated with porcelain aorta

International Nuclear Information System (INIS)

Daitoku, Kazuyuki; Fukui, Kozo; Ichinoseki, Ikkoh; Munakata, Mamoru; Takahashi, Shoichi; Fukuda Ikuo

2004-01-01

Mediastinal irradiation has been reported to induce cardiac disease such as pericarditis, valvular dysfunction, conduction abnormalities, accelerated arteriosclerosis of the coronary arteries, and also calcifications of the ascending aorta. We herein describe a case of radiotherapy-induced porcelain aorta and aortic valve disease and their surgical treatment. The patient was diagnosed with myasthenia gravis (MG) in 1965 (Osserman's type II), and mediastinal irradiation was performed in 1970 for treatment of thymic tumor associated with MG. Thirty years after radiation therapy, complete atrioventricular block and aortic valve disease with severe calcification of the ascending aorta and aortic arch (porcelain aorta) were detected on echo cardiogram and cardiac catheterization. A permanent pacemaker was implanted via the left subclavian vein and aortic valve replacement was performed under extracorporeal circulation established by selective cerebral perfusion and balloon occlusion instead of aortic cross-clamping. As no risk factors of arteriosclerosis such as hypercholesterolemia, hyperglycemia and hypertension were apparent, we concluded that the aortic valve disease and porcelain aorta were primarily induced by radiotherapy. (author)

Rare early prosthesis obstruction after mitral valve replacement: a case report and literature review

Directory of Open Access Journals (Sweden)

Shi Jun

2012-07-01

Full Text Available Abstract As a dreadful complication after the mechanical heart valve replacement, prosthetic valve obstruction caused by pannus formation occurs increasingly with time. The authors here present a case of 42-year-old woman who was urgently admitted to hospital with acute heart failure symptoms due to the mechanical mitral valve failure only 3 months after surgery. Transthoracic and transesophageal echocardiography demonstrated that the bileaflet of the mitral prosthesis were completely immobilized with only a small transvalvular jet remained. During the reoperation, the reason of the prosthetic valve obstruction was attributed to the noncircular pannus ingrowth extending from the atrioventricular side. For a better understanding of the prosthetic valve dysfunction caused by pannus formation, the authors then compile a literature review to briefly discuss the status quo of the clinical characteristics of this uncommon complication.

Percutaneous aortic valve implantation of the Medtronic CoreValve self-expanding valve prosthesis via left subclavian artery access: the first case report in Greece.

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Karavolias, George K; Georgiadou, Panagiota; Houri, Mazen; Sbarouni, Eftihia; Thomopoulou, Sofia; Tsiapras, Dimitrios; Smirli, Anna; Balanika, Marina; Voudris, Vassilis

2010-01-01

This case report describes a percutaneous aortic valve implantation with the Medtronic CoreValve selfexpanding valve prosthesis in a patient with severe aortic stenosis. The approach was made via the left subclavian artery because of the lack of femoral vessel access. The patient was a 78-year-old female with breathlessness on minimal effort, a recent hospitalisation due to pulmonary oedema, and frequent episodes of pre-syncope; surgical valve replacement had been ruled out. The prosthetic valve was successfully implanted with mild paravalvular aortic regurgitation. At 30 days, the patient's clinical condition had significantly improved, with excellent functioning of the aortic valve prosthesis.

Impact of bicuspid aortic valve on complications and death in infective endocarditis of native aortic valves.

Science.gov (United States)

Kahveci, Gokhan; Bayrak, Fatih; Pala, Selcuk; Mutlu, Bulent

2009-01-01

We retrospectively investigated the impact of bicuspid aortic valve on the prognosis of patients who had definite infective endocarditis of the native aortic valve.Of 51 patients, a bicuspid aortic valve was present in 22 (43%); the other 29 had tricuspid aortic valves. On average, the patients who had bicuspid valves were younger than those who had tricuspid valves. Patients with a tricuspid valve had larger left atrial diameters and were more likely to have severe mitral regurgitation.Periannular complications, which we detected in 19 patients (37%), were much more common in the patients who had a bicuspid valve (64% vs 17%, P = 0.001). The presence of a bicuspid valve was the only significant independent predictor of periannular complications. The in-hospital mortality rate in the bicuspid group was lower than that in the tricuspid group; however, this figure did not reach statistical significance (9% vs 24%, P = 0.15). In multivariate analysis, left atrial diameter was the only independent predictor associated with an increased risk of death (hazard ratio, 2.19; 95% confidence interval, 1.1-4.5; P = 0.031).In our study, patients with infective endocarditis in a bicuspid aortic valve were younger and had a higher incidence of periannular complications. Although a worse prognosis has been reported previously, we found that infective endocarditis in a native bicuspid aortic valve is not likely to increase the risk of death in comparison with infective endocarditis in native tricuspid aortic valves.

Categorization of safety related motor operated valve safety significance for Ulchin Unit 3

International Nuclear Information System (INIS)

Kang, D. I.; Kim, K. Y.

2002-03-01

We performed a categorization of safety related Motor Operated Valve (MOV) safety significance for Ulchin Unit 3. The safety evaluation of MOV of domestic nuclear power plants affects the generic data used for the quantification of MOV common cause failure ( CCF) events in Ulchin Units 3 PSA. Therefore, in this study, we re-estimated the MGL(Multiple Greek Letter) parameter used for the evaluation of MOV CCF probabilities in Ulchin Units 3 Probabilistic Safety Assessment (PSA) and performed a classification of the MOV safety significance. The re-estimation results of the MGL parameter show that its value is decreased by 30% compared with the current value in Ulchin Unit 3 PSA. The categorization results of MOV safety significance using the changed value of MGL parameter shows that the number of HSSCs(High Safety Significant Components) is decreased by 54.5% compared with those using the current value of it in Ulchin Units 3 PSA

Natural history of subclinical leaflet thrombosis affecting motion in bioprosthetic aortic valves

DEFF Research Database (Denmark)

Sondergaard, Lars; De Backer, Ole; Kofoed, Klaus F

2017-01-01

. No patients developed symptoms of valve dysfunction and leaflet thickening was not clearly associated with any clinical events. Conclusions: Subclinical leaflet thrombosis is a common finding after TAVI and SAVR, and may progress from normal leaflet over HALT to the more severe HAM. The phenomenon can develop...

Complete Transversal Disc Fracture in a Björk-Shiley Delrin Mitral Valve Prosthesis 43 Years After Implantation.

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González-Santos, Jose María; Arnáiz-García, María Elena; Dalmau-Sorlí, María José; Sastre-Rincón, Jose Alfonso; Hernández-Hernández, Jesús; Pérez-Losada, María Elena; Sagredo-Meneses, Víctor; López-Rodríguez, Javier

2016-10-01

A patient who underwent previous implantation of a mitral valve replacement with a Björk-Shiley Delrin (BSD) mitral valve prosthesis during infancy was admitted to our institution 43 years later after an episode of syncope and cardiac arrest. Under extreme hemodynamic instability, a mitral valve prosthetic dysfunction causing massive mitral regurgitation was identified. The patient underwent an emergent cardiac operation, and a complete disc fracture with partial disc migration was found. Exceptional cases of mechanical prosthetic heart valve fracture exist. We report the first case of complete transversal disc rupture of a BSD mitral valve prosthesis after the longest period of implantation ever reported in that position. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

[Reoperative valve replacement in patients undergoing cardiac reoperation: a report of 104 cases].

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Zou, Liang-jian; Xu, Zhi-yun; Wang, Zhi-nong; Lang, Xi-long; Han, Lin; Lu, Fang-lin; Xu, Ji-bin; Tang, Hao; Ji, Guang-yu; Wang, Er-song; Wang, Jun; Qu, Yi

2010-08-15

To review the experience of reoperative valve replacement for 104 patients. From January 2002 to December 2009, 104 patients underwent heart valve replacement in reoperations, accounting for 2.92% of the total patient population (3557 cases) who had valve replacement during this period. In this group, 53 male and 51 female patients were included with a median age of 46 years (ranged from 13 to 72 years). The reasons of reoperation included 28 cases suffered from another valve lesion after valve replacement, 10 cases suffered from valve lesion after mitral valvuloplasty, 19 cases suffered from perivalvular leakage after valve replacement, 18 cases suffered from valve lesion after previous correction of congenital heart defect, 7 cases suffered from bioprosthetic valve decline, 10 cases suffered from prosthetic valve endocarditis, 9 cases suffered from dysfunction of machine valve, and 3 cases suffered from other causes. The re-operations were mitral and aortic valve replacement in 2 cases, mitral valve replacement in 59 cases, aortic valve replacement in 24 cases, tricuspid valve replacement in 16 cases, and Bentall's operation in 3 cases. The interval from first operation to next operation was 1 month-19 years. There were 8 early deaths from heart failure, renal failure and multiple organ failure (early mortality 7.69%). Major complications were intraoperative hemorrhage in 2 cases, re-exploration for mediastinal bleeding in 2 cases and sternotomy surgical site infection in 1 case. Complete follow-up (3 months-7 years and 2 months) was available for all patients. Two patients died, one patient died of intracranial hemorrhage, and another cause was unknown. Satisfactory short-term and long-term results can be obtained in reoperative valve replacement with appropriate timing of operation control, satisfactory myocardial protection, accurate surgical procedure and suitable perioperative treatment.

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

Science.gov (United States)

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

2017-02-15

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

Fresh Autologous Pericardium to Reconstruct the Pulmonary Valve at the Annulus When Tetralogy of Fallot Requires a Transannular Patch at Midterm.

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Pande, Shantanu; Sharma, Jugal K; Siddartha, C R; Bansal, Anubhav; Agarwal, Surendra K; Tewari, Prabhat; Kapoor, Aditya

2016-06-01

Tetralogy of Fallot often requires reconstruction of the right ventricular outflow tract with a transannular patch (TAP), but this renders the pulmonary valve incompetent and eventually leads to right ventricular dysfunction. We retrospectively evaluated the efficacy of a reconstructed pulmonary valve and annulus in 70 patients who underwent, from December 2006 through December 2010, complete correction of tetralogy of Fallot. We divided the 70 patients into 2 groups in accordance with whether they required (n=50) or did not require (n=20) a TAP. We used autologous untreated pericardium to fashion the TAP and to create both an annulus of the correct size and a competent pulmonary valve with native leaflets. We evaluated the efficiency of this procedure both functionally and anatomically. The median age of the patients was 11 years (range, 2-38 yr). There were 56 males, with no significant difference in sexual distribution between groups. The clinical follow-up was 88% for 57.5 months, and the echocardiographic follow-up was 80% for 36 months. There was no significant difference in outflow gradient or in the occurrence of pulmonary insufficiency between the TAP group (none, 31; mild, 12; moderate, 6; and severe, 1) and the No-TAP group (none, 16; moderate, 2; and severe, 2) (P=0.59). Nor was there any thickening or calcification in the constructed valves. We conclude that pulmonary valves constructed of untreated autologous pericardium performed as well as native valves after total tetralogy of Fallot correction at midterm.

Depth of valve implantation, conduction disturbances and pacemaker implantation with CoreValve and CoreValve Accutrak system for Transcatheter Aortic Valve Implantation, a multi-center study.

Science.gov (United States)

Lenders, Guy D; Collas, Valérie; Hernandez, José Maria; Legrand, Victor; Danenberg, Haim D; den Heijer, Peter; Rodrigus, Inez E; Paelinck, Bernard P; Vrints, Christiaan J; Bosmans, Johan M

2014-10-20

Transcatheter Aortic Valve Implantation (TAVI) is now considered an indispensable treatment strategy in high operative risk patients with severe, symptomatic aortic stenosis. However, conduction disturbances and the need for Permanent Pacemaker (PPM) implantation after TAVI with the CoreValve prosthesis still remain frequent. We aimed to evaluate the implantation depth, the incidence and predictors of new conduction disturbances, and the need for PPM implantation within the first month after TAVI, using the new Accutrak CoreValve delivery system (ACV), compared to the previous generation CoreValve (non-ACV). In 5 experienced TAVI-centers, a total of 120 consecutive non-ACV and 112 consecutive ACV patients were included (n=232). The mean depth of valve implantation (DVI) was 8.4±4.0 mm in the non-ACV group and 7.1±4.0 mm in the ACV group (p=0.034). The combined incidence of new PPM implantation and new LBBB was 71.2% in the non-ACV group compared to 50.5% in the ACV group (p=0.014). DVI (p=0.002), first degree AV block (p=0.018) and RBBB (p<0.001) were independent predictors of PPM implantation. DVI (p<0.001) and pre-existing first degree AV-block (p=0.021) were identified as significant predictors of new LBBB. DVI is an independent predictor of TAVI-related conduction disturbances and can be reduced by using the newer CoreValve Accutrak delivery system, resulting in a significantly lower incidence of new LBBB and new PPM implantation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Novel imaging strategies for the Detection of Prosthetic Heart Valve Obstruction and Endocarditis

NARCIS (Netherlands)

Tanis, W.

2014-01-01

Valvular heart disease is accompanied by a high mortality/morbidity and often requires prosthetic heart valve (PHV) replacement in order to improve quality of life and survival. The major drawback of both mechanical and biological PHV implantations is development of dysfunction, which is a life

Echocardiographic Evidence of Early Diastolic Dysfunction in Asymptomatic Children with Osteogenesis Imperfecta

Directory of Open Access Journals (Sweden)

Khalfan S. Al-Senaidi

2015-11-01

Full Text Available Objectives: Structural and functional cardiovascular abnormalities have been reported in adults with osteogenesis imperfecta (OI; however, there is a lack of paediatric literature on this topic. This study aimed to investigate cardiovascular abnormalities in children with OI in comparison to a control group. Methods: This case-control study was conducted at the Sultan Qaboos University Hospital in Muscat, Oman, between May 2013 and August 2014. Data from eight patients with OI and 24 healthy controls were compared using conventional and tissue Doppler echocardiography (TDE. Results: The OI group had significantly lower peak early mitral valve flow velocity (P = 0.027, peak a-wave reversal in the pulmonary vein (P = 0.030 and peak early diastolic velocity of the mitral valve and upper septum (P = 0.001 each. The peak late diastolic velocities of the mitral valve (P = 0.002 and the upper septum (P = 0.037 were significantly higher in the OI group; however, the peak early/late diastolic velocity ratios of the mitral valve (P = 0.002 and upper septum (P = 0.001 were significantly lower. Left ventricular dimensions and aortic and pulmonary artery diameters were larger in the OI group when indexed for body surface area. Both groups had normal systolic cardiac function. Conclusion: Children with OI had normal systolic cardiac function. However, changes in myocardial tissue Doppler velocities were suggestive of early diastolic cardiac dysfunction. They also had increased left ventricular dimensions and greater vessel diameters. These findings indicate the need for early and detailed structural and functional echocardiographic assessment and follow-up of young patients with OI.

Endothelial function and dysfunction: clinical significance and assessment

Directory of Open Access Journals (Sweden)

Shaghayegh Haghjooyejavanmard

2008-08-01

Full Text Available

• Over the past two decades, investigators have increasingly recognized the importance of the endothelium as a centralregulator of vascular and body homeostasis. The endothelial lining represents an organ of 1.5 kg in an adult, which is distributed throughout the body. The endothelium is versatile and multifunctional. In addition to its role as a selective permeability barrier, it has many synthetic and metabolic properties, including modulation of vascular tone and blood flow, regulation of immune and inflammatory responses, and regulation of coagulation, fibrinolysis and thrombosis. Endothelial dysfunction (ED is a frequently used term, which can be referred to abnormalities in various physiological functions of the endothelium, and it is known as a key variable in the pathogenesis of several diseases and their complications. Finding suitable markers for endothelial damage or ED is certainly of interest. Established and emerging techniques to detect ED are divided into three large families of functional, cellular, and biochemical markers. Instead of performing single assessments, it may be much more valuable to determine various biological aspects of endothelium. It seems that there is likely a spectrum between normality, endothelial activation (by inflammatory cytokines, endothelial dysfunction (e.g., impairment of nitric oxide, resulting in loss of regulation of vascular tone and endothelial damage (e.g., atherosclerosis. In this review we review the importance of endothelium and its activation, biomarkers and dysfunction.
•  KEYWORDS: Endothelial function, endothelium, Disease.

Effects of Pannus Formation on the Flow around a Bileaflet Mechanical Heart Valve

Science.gov (United States)

Kim, Woojin; Choi, Haecheon; Kweon, Jihoon; Yang, Dong Hyun; Kim, Namkug; Kim, Young-Hak

2013-11-01

A pannus, an abnormal layer of fibrovascular tissue observed on a bileaflet mechanical heart valve (BMHV), induces dysfunctions of BMHV such as the time delay and incomplete valve closing. We numerically simulate the flows around an intra-annular type BMHV model with and without pannus formation, respectively, and investigate the flow and bileaflet-movement modifications due to the pannus formation. Simulations are conducted at a physiological condition (mean flow rate of 5 l/min, cycle duration of 866 ms, and the Reynolds number of 7200 based on the inflow peak bulk velocity and inflow diameter). We model the pannus as an annulus with fixed outer radius and vary the inner radius of the pannus. Our preliminary results indicate that the flow field changes significantly and the bileaflet does not close properly due to the pannus formation. The detailed results will be given at the final presentation. Supported by the NRF Programs (NRF-2011-0028032, NRF-2012M2A8A4055647).

Novel self-expandable, stent-based transcatheter pulmonic valve: a preclinical animal study.

Science.gov (United States)

Kim, Gi Beom; Lim, Hong-Gook; Kim, Yong Jin; Choi, Eun Young; Kwon, Bo Sang; Jeong, Saeromi

2014-04-15

Because transcatheter implantation of pulmonary valve is indicated for limited-size dysfunctional right ventricular outflow tract only as a balloon-expandable stent, we investigated the feasibility of a large-diameter self-expandable valved stent and the durability of the valve after >6 months. We made a nitinol-wire-based, self-expandable valved stent with leaflets made from porcine pericardium. The porcine pericardium was treated with α-galactosidase, glutaraldehyde, and glycine after decellularization. After cutting the inguinal or cervical area, we implanted a valved stent in 12 sheep through the femoral or jugular vein by using an 18-Fr delivery catheter, controlling the catheter handles and hook block under fluoroscopic and echocardiographic guidance. The mean body weight of sheep was 43.9 kg. We successfully implanted valved stents (diameter: 24 mm in 7 sheep, 26 mm in 5 sheep) in good position in 8 sheep, in the main pulmonary artery (PA) in 2 sheep, and in the right ventricular outlet tract (RVOT) in 2 sheep. We sacrificed 8 sheep (6 sheep in good position, 1 sheep in the main PA, and 1 sheep in the RVOT) after >6 months. Five of the 6 sheep implanted in good position showed well-preserved valve morphology at the time of sacrifice. Histologic findings after routine sacrifice showed well-maintained collagen wave structure and no visible calcification in all explanted valve leaflets. Transcatheter implantation of a nitinol-wire-based, self-expandable valved stent in the pulmonic valve was feasible, and stents implanted in good position showed well-preserved valve leaflets with functional competence in the mid-term results. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

[POL-PAVTI--Polish report on transcatheter pulmonary artery valve implantation of Melody-Medtronic prosthesis in the first 14 patients in Poland].

Science.gov (United States)

Ruzyłło, Witold; Demkow, Marcin; Włodarska, Elzbieta K; Kowalski, Mirosław; Spiewak, Mateusz; Siudalska, Hanna; Wolski, Piotr; Miśko, Jolanta; Hoffman, Piotr; Kusa, Jacek; Szkutnik, Małgorzata; Białkowski, Jacek; Fiszer, Roland; Urbańska, Ewa; Sondergaard, Lars

2009-10-01

To assess the early results of the pulmonary artery valve transcatheter implantation (PAVTI) in pts included into POL-PAVTI registry. Detailed medical and economic analyses were performed. Pulmonary artery valve implantation was performed in 14 pts (9 men), aged 16-31 (mean 24.6 +/- 4.8) years, with pulmonary homograft dysfunction after total repair of tetralogy of Fallot (4 pts), pulmonary atresia (2 pts), pulmonary stenosis (1 pt), common arterial trunk type I (1 pt), Ross procedure (3 pts) and TGA - Rastelli operation (3 pts). Eleven pts underwent in the past 2-5 surgical or/and catheter interventions. Indication for PAVTI was based on clinical evaluation and echocardiographic studies. Assessment of morphological and functional features of the right ventricle (RV) and homograft with the use of cardiac magnetic resonance (CMR) was performed in 10 cases. Pulmonary stenosis (max. pulmonary gradient 32-119, mean 72 +/- 28 mmHg) was observed in 13 pts and/or significant pulmonary regurgitation in 10 pts. The procedure was performed in general anesthesia. The deployment of a valved stent in the pulmonary valve position was preceded by a metal stent implantation. Results were evaluated by echocardiography two days after the procedure and one month later. Four patients were evaluated 6 months after procedure. Time of the procedure varied 60-190 (mean 127 +/- 35) min, time of fluoroscopy ranged 12-31 (mean 21 +/- 11) min. PAVTI was successfully performed in all pts without serious complications. Patients were discharged from the hospital 48-293 (mean 120 +/- 71) h after procedure. Significant reduction of pulmonary gradient after the procedure assessed by echocardiography was observed on the second day (20-60, mean 38 +/- 12 mmHg, p < 0.0001) and one month (19-52, mean 34 +/- 9 mmHg, p < 0.0001). Mild pulmonary regurgitation was observed in 2 pts. In 5 pts evaluated 6 months after procedure haemodynamic parameters were unchanged; no late complications were observed

The clinical significance of perivalvular pannus in prosthetic mitral valves: Can cardiac CT be helpful?

Science.gov (United States)

Chang, Suyon; Suh, Young Joo; Han, Kyunghwa; Kim, Jin Young; Kim, Young Jin; Chang, Byung-Chul; Choi, Byoung Wook

2017-12-15

The clinical significance of pannus in the prosthetic mitral valve (MV) is not well documented. To investigate the clinical significance of pannus on cardiac computed tomography (CT) in patients with a prosthetic MV. A total of 130 patients with previous MV replacement who underwent cardiac CT were retrospectively included in this study. The presence of pannus, paravalvular leak (PVL) around the prosthetic MV and limitation of motion (LOM) of the MV were analyzed using CT. Between patients with MV pannus and those without pannus, CT, echocardiographic, and redo-surgery findings were compared. The diagnostic performance of CT and transesophageal echocardiography (TEE) for the detection of MV pannus was also compared, using surgical findings as a standard reference. MV pannus was observed on cardiac CT in 32.3% of the study population. Patients with MV pannus detected on CT more commonly had LOM (28.2% vs. 15.2%) and less frequently had PVL of the prosthetic MV (16.7% vs. 25%) than patients without MV pannus (P>0.05). Prosthetic valve obstruction (PVO) due prosthetic MV pannus requiring redo-surgery was present in only five patients (11.9%). Cardiac CT detected MV pannus with sensitivity of 65.2% and specificity of 80.9% and showed better diagnostic performance than TEE (Ppannus can frequently be seen on cardiac CT. However, its clinical significance should be assessed with careful consideration, because PVO due to MV pannus is relatively uncommon, and pannus can be seen in patients without any clinical problems. Copyright © 2017 Elsevier B.V. All rights reserved.

Transcatheter Pulmonary Valve Replacement: Current State of Art.

Science.gov (United States)

Alkashkari, Wail; Alsubei, Amani; Hijazi, Ziyad M

2018-03-15

The past couple of decades have brought tremendous advances to the field of pediatric and adult congenital heart disease (CHD). Percutaneous valve interventions are now a cornerstone of not just the congenital cardiologist treating patients with congenital heart disease, but also-and numerically more importantly-for adult interventional cardiologists treating patients with acquired heart valve disease. Transcatheter pulmonary valve replacement (tPVR) is one of the most exciting recent developments in the treatment of CHD and has evolved to become an attractive alternative to surgery in patients with right ventricular outflow tract (RVOT) dysfunction. This review aims to summarize (1) the current state of the art for tPVR, (2) the expanding indications, and (3) the technological obstacles to optimizing tPVR. Since its introduction in 2000, more than ten thousands tPVR procedures have been performed worldwide. Although the indications for tPVR have been adapted earlier from those accepted for surgical intervention, they remain incompletely defined. The new imaging modalities give better assessment of cardiac anatomy and function and determine candidacy for the procedure. The procedure has been shown to be feasible and safe when performed in patients who received pulmonary conduit and or bioprosthetic valves between the right ventricle and the pulmonary artery. Fewer selected patients post trans-annular patch repair for tetralogy of Fallot may also be candidates for this technology. Size restrictions of the currently available valves limit deployment in the majority of patients post trans-annular patch repair. Newer valves and techniques are being developed that may help such patients. Refinements and further developments of this procedure hold promise for the extension of this technology to other patient populations.

Aortic Regurgitation in Patients Undergoing Transcatheter Aortic Valve Replacement With the Self-Expanding CoreValve Versus the Balloon-Expandable SAPIEN XT Valve.

Science.gov (United States)

Kiramijyan, Sarkis; Magalhaes, Marco A; Koifman, Edward; Didier, Romain; Escarcega, Ricardo O; Baker, Nevin C; Negi, Smita I; Minha, Sa'ar; Torguson, Rebecca; Jiaxiang, Gai; Asch, Federico M; Wang, Zuyue; Okubagzi, Petros; Gaglia, Michael A; Ben-Dor, Itsik; Satler, Lowell F; Pichard, Augusto D; Waksman, Ron

2016-05-01

The incidence of aortic regurgitation (AR) after transcatheter aortic valve replacement (TAVR) in a self-expanding and a balloon-expandable system is controversial. This study aimed to examine the incidence and severity of post-TAVR AR with the CoreValve (CV) versus the Edwards XT Valve (XT). Baseline, procedural, and postprocedural inhospital outcomes were compared. The primary end point was the incidence of post-TAVR AR of any severity, assessed with a transthoracic echocardiogram, in the CV versus XT groups. A multivariate logistic regression analysis was completed to evaluate for correlates of the primary end point. The secondary end points included the change in severity of AR at 30-day and 1-year follow-up. A total of 223 consecutive patients (53% men, mean age 82 years) who had transfemoral TAVR with either a CV (n = 119) or XT (n = 104) were evaluated. The rates of post-TAVR AR in the groups were similar, and there was no evidence of more-than-moderate AR in either group. There were significant differences in the rates of intraprocedural balloon postdilation with the CV (17.1%) versus XT valve (5.8%; p = 0.009) and in the rates of intraprocedural implantation of a second valve-in-valve prosthesis with the CV (9.9%) versus XT valve (2.2%; p = 0.036). There were no significant differences in inhospital safety outcomes between the 2 groups. In conclusion, the incidence of post-TAVR AR is similar between the CV and the XT valve when performed by experienced operators using optimal intraprocedural strategies, as deemed appropriate, to mitigate the severity of AR. Copyright © 2016 Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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.

Effects of aging and service wear on main steam isolation valves and valve operators

International Nuclear Information System (INIS)

Clark, R.L.

1996-03-01

In recent years main steam isolation valve (MSIV operating problems have resulted in significant operational transients (e.g., spurious reactor trips, steam generator dry out, excessive valve seat leakage), increased cost, and decreased plant availability. A key ingredient to an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. A detailed review of historical failure data available through the Institute of Nuclear Power Operation's Nuclear Plant Reliability Data System has been conducted for several types of MSIVs and valve operators for both boiling-water reactors and pressurized-water reactors. The focus of this review is on MSIV failures modes, actuator failure modes, consequences of failure on plant operations, method of failure detection, and major stressors affecting both valves and valve operators

Mechanisms of recurrent aortic regurgitation after aortic valve repair: predictive value of intraoperative transesophageal echocardiography.

Science.gov (United States)

le Polain de Waroux, Jean-Benoît; Pouleur, Anne-Catherine; Robert, Annie; Pasquet, Agnès; Gerber, Bernhard L; Noirhomme, Philippe; El Khoury, Gébrine; Vanoverschelde, Jean-Louis J

2009-08-01

The aim of the present study was to examine the intraoperative echocardiographic features associated with recurrent severe aortic regurgitation (AR) after an aortic valve repair surgery. Surgical valve repair for AR has significant advantages over valve replacement, but little is known about the predictors and mechanisms of its failure. We blindly reviewed all clinical, pre-operative, intraoperative, and follow-up transesophageal echocardiographic data of 186 consecutive patients who underwent valve repair for AR during a 10-year period and in whom intraoperative and follow-up echo data were available. After a median follow-up duration of 18 months, 41 patients had recurrent 3+ AR, 23 patients presented with residual 1+ to 2+ AR, and 122 had no or trivial AR. In patients with recurrent 3+ AR, the cause of recurrent AR was the rupture of a pericardial patch in 3 patients, a residual cusp prolapse in 26 patients, a restrictive cusp motion in 9 patients, an aortic dissection in 2 patients, and an infective endocarditis in 1 patient. Pre-operatively, all 3 groups were similar for aortic root dimensions and prevalence of bicuspid valve (overall 37%). Patients with recurrent AR were more likely to display Marfan syndrome or type 3 dysfunction pre-operatively. At the opposite end, patients with continent AR repair at follow-up were more likely to have type 2 dysfunction pre-operatively. After cardiopulmonary bypass, a shorter coaptation length, the degree of cusp billowing, a lower level of coaptation (relative to the annulus), a larger diameter of the aortic annulus and the sino-tubular junction, the presence of a residual AR, and the width of its vena contracta were associated with the presence of AR at follow-up. Multivariate Cox analysis identified a shorter coaptation length (odds ratio [OR]: 0.8, p = 0.05), a coaptation occurring below the level of the aortic annulus (OR: 7.9, p < 0.01), a larger aortic annulus (OR: 1.2, p = 0.01), and residual aortic regurgitation

Surgical Treatment of Posterior Mitral Valve Prolapse: Towards 100% Repair.

Science.gov (United States)

Correia, Pedro M; Coutinho, Gonçalo F; Branco, Carlos; Garcia, Ana; Antunes, Manuel J

2015-11-01

The study aim was to evaluate the immediate and long-term results of surgical treatment of isolated posterior mitral valve leaflet prolapse (PLP), focusing on survival and freedom from recurrent mitral regurgitation (MR). Between January 1998 and December 2012, a total of 492 consecutive patients (375 males, 117 females; mean age 61.8 ± 12.1 years; range: 13-86 years) with isolated PLP [304 (61.8%) with myxomatous degeneration; 188 (38.2%) with fibroelastic deficiency] were treated at the authors' institution. Of these patients, 202 (41.1%) were in NYHA class III-IV, and atrial fibrillation was present in 104 (21.1%). Mitral valve repair was achieved in 484 patients (98.4%), resection was performed in 419 (85.2%), and prosthetic ring annuloplasty was used in 436 (88.6%). Concomitant procedures were performed in 153 patients (31.1%), including tricuspid valve repair in 50 (10.2%), aortic valve surgery in 34 (6.9%), and coronary artery bypass grafting (CABG) in 64 (13%). The hospital mortality rate was 0.2%, and the mean follow up was 7.1 ± 3.9 years. There were 71 late deaths (14.4%), and overall survival at five, 10 and 15 years was 91.7 ± 1.3%, 82.1 ± 2.3% and 64.7 ± 6.1%, respectively. There was no significant difference in long-term survival compared with the age- and gender-matched general population (p = 0.146). Multivariate Cox-proportional hazard analysis showed older age (HR 1.03 per annum), left ventricular dysfunction (HR 2.44), atrial fibrillation (HR 1.96), left ventricular end-diastolic dimension (HR 1.05 per mm) and non-use of prosthetic ring (HR 3.03) as significant predictors of late mortality. Recurrence of moderate or severe MR occurred in 31 patients, six of whom underwent mitral valve reoperation. Predictors of late recurrence of MR were fibroelastic deficiency (HR 2.38), mitral calcification (HR 5.26), posterior leaflet plication (HR 3.58), absence of complete ring annuloplasty (HR 3.84) and systolic pulmonary artery pressure at discharge

Turbulence downstream of subcoronary stentless and stented aortic valves.

Science.gov (United States)

Funder, Jonas Amstrup; Frost, Markus Winther; Wierup, Per; Klaaborg, Kaj-Erik; Hjortdal, Vibeke; Nygaard, Hans; Hasenkam, J Michael

2011-08-11

Regions of turbulence downstream of bioprosthetic heart valves may cause damage to blood components, vessel wall as well as to aortic valve leaflets. Stentless aortic heart valves are known to posses several hemodynamic benefits such as larger effective orifice areas, lower aortic transvalvular pressure difference and faster left ventricular mass regression compared with their stented counterpart. Whether this is reflected by diminished turbulence formation, remains to be shown. We implanted either stented pericardial valve prostheses (Mitroflow), stentless valve prostheses (Solo or Toronto SPV) in pigs or they preserved their native valves. Following surgery, blood velocity was measured in the cross sectional area downstream of the valves using 10MHz ultrasonic probes connected to a dedicated pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at two different blood pressures (baseline and 50% increase). We found no difference in maximum RNS measurements between any of the investigated valve groups. The native valve had significantly lower mean RNS values than the Mitroflow (p=0.004), Toronto SPV (p=0.008) and Solo valve (p=0.02). There were no statistically significant differences between the artificial valve groups (p=0.3). The mean RNS was significantly larger when increasing blood pressure (p=0.0006). We, thus, found no advantages for the stentless aortic valves compared with stented prosthesis in terms of lower maximum or mean RNS values. Native valves have a significantly lower mean RNS value than all investigated bioprostheses. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

Wells, Beric E.

2012-12-21

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

The management of patients with aortic regurgitation and severe left ventricular dysfunction: a systematic review.

Science.gov (United States)

Badar, Athar A; Brunton, Alan P T; Mahmood, Ammad H; Dobbin, Stephen; Pozzi, Andrea; McMinn, Jenna F; Sinclair, Andrew J E; Gardner, Roy S; Petrie, Mark C; Curry, Phil A; Al-Attar, Nawwar H K; Pettit, Stephen J

2015-01-01

A systematic search of Medline, EMBASE and CINAHL electronic databases was performed. Original research articles reporting all-cause mortality following surgery in patients with aortic regurgitation and severe left ventricular systolic dysfunction (LVSD) were identified. Nine of the 10 eligible studies were observational, single-center, retrospective analyses. Survival ranged from 86 to 100% at 30 days; 81 to 100% at 1 year and 68 to 84% at 5 years. Three studies described an improvement in mean left ventricular ejection fraction (LVEF) following aortic valve replacement (AVR) of 5-14%; a fourth study reported an increase in mean left ventricular ejection fraction (LVEF) of 9% in patients undergoing isolated AVR but not when AVR was combined with coronary artery bypass graft and/or mitral valve surgery. Three studies demonstrated improvements in functional New York Heart Association (NYHA) class following AVR. Additional studies are needed to clarify the benefits of AVR in patients with more extreme degrees of left ventricular systolic dysfunction (LVSD) and the potential roles of cardiac transplantation and transaortic valve implantation.

Long-Term Outcomes of Homografts in the Aortic Valve and Root Position: A 20-Year Experience

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Joo Yeon Kim

2016-08-01

Full Text Available Background: The advantages of using a homograft in valve replacement surgery are the excellent hemodynamic profile, low risk of thromboembolism, and low risk of prosthetic valve infection. The aim of this study was to evaluate the long-term outcomes of homograft implantation in the aortic valve position. Methods: This is a retrospective study of 33 patients (＞20 years old who underwent aortic valve replacement or root replacement with homografts between April 1995 and May 2015. Valves were collected within 24 hours from explanted hearts of heart transplant recipients (＜60 years and organ donors who were not suitable for heart transplantation. The median follow-up duration was 35.6 months (range, 0 to 168 months. Results: Aortic homografts were used in all patients. The 30-day mortality rate was 9.1%. The 1- and 5-year survival rates were 80.0%±7.3% and 60.8%±10.1%, respectively. The 1-, 5-, and 10-year freedom from reoperation rates were 92.3%±5.2%, 68.9%±10.2%, and 50.3%±13.6%, respectively. The 1-, 5-, and 10-year freedom from significant aortic dysfunction rates were 91.7%±8.0%, 41.7%±14.2%, and 25.0%±12.5%, respectively. Conclusion: Homografts had the advantages of a good hemodynamic profile and low risk of thromboembolic events, and with good outcomes in cases of aortitis.

Check valve

Science.gov (United States)

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.

Check valve

International Nuclear Information System (INIS)

Upton, H.A.; Garcia, P.

1999-01-01

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

NRC valve performance test program - check valve testing

International Nuclear Information System (INIS)

Jeanmougin, N.M.

1987-01-01

The Valve Performance Test Program addresses the current requirements for testing of pressure isolation valves (PIVs) in light water reactors. Leak rate monitoring is the current method used by operating commercial power plants to survey the condition of their PIVs. ETEC testing of three check valves (4-inch, 6-inch, and 12-inch nominal diameters) indicates that leak rate testing is not a reliable method for detecting impending valve failure. Acoustic emission monitoring of check valves shows promise as a method of detecting loosened internals damage. Future efforts will focus on evaluation of acoustic emission monitoring as a technique for determining check valve condition. Three gate valves also will be tested to evaluate whether the check valve results are applicable to gate type PIVs

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

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Harish Ramakrishna

2015-01-01

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

A systematic review on renal and bladder dysfunction after endoscopic treatment of infravesical obstruction in boys.

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Pauline M L Hennus

Full Text Available BACKGROUND: Posterior urethral valves (PUV may cause subtle to severe obstruction of the urethra, resulting in a broad clinical spectrum. PUV are the most common cause of chronic renal disease in boys. Our purpose was to report the incidences of kidney and bladder dysfunction in boys treated with endoscopic valve resection for PUV. METHODOLOGY: We searched MEDLINE and EMBASE databases until 1st of July 2011, to identify original papers that described outcome of endoscopic valve resection (EVR in boys. We extracted information on (1 patient characteristics and clinical presentation of PUV related to outcomes and (2 the post-treatment absolute risks for kidney and bladder dysfunction. PRINCIPAL FINDINGS: Thirty-four studies describing renal function, vesicoureteral reflux (VUR, incontinence, and urodynamic bladder function after EVR in 1474 patients were retrieved. Patients treated for PUV show high percentages of chronic kidney disease (CKD or end stage renal disease (ESRD, 22% (0-32% and 11% (0-20%, respectively. Elevated nadir serum creatinine was the only independent factor associated with renal failure. Before treatment, VUR was present in 43% of boys and after EVR, VUR was present in 22%. Post treatment, 19% (0-70% was reported to suffer from urinary incontinence. Urodynamic bladder dysfunction was seen in many patients (55%, 0-72% after treatment of PUV. CONCLUSIONS: The reported cumulative incidence of renal and bladder dysfunction in patients with PUV after endoscopic PUV treatment varies widely. This may reflect a broad clinical spectrum, which relates to the lack of a standardised quantification of obstruction and its severity. Moreover, the risk of bias is rather high, and therefore we put little confidence in the reported estimates of effect. We found elevated nadir serum creatinine as a predictor for renal dysfunction. In order to be able to predict outcomes for patients with PUV, an objective classification of severity of

Comparison of magnetic resonance imaging and Laser Doppler Anemometry velocity measurements downstream of replacement heart valves: implications for in vivo assessment of prosthetic valve function.

Science.gov (United States)

Fontaine, A A; Heinrich, R S; Walker, P G; Pedersen, E M; Scheidegger, M B; Boesiger, P; Walton, S P; Yoganathan, A P

1996-01-01

The non-invasive, in-vivo assessment of prosthetic valve function is compromised by the lack of accurate measurements of the transvalvular flow fields or hemodynamics by current techniques. Short echo time magnetic resonance imaging (MRI) may provide a method for the non-invasive, in vivo assessment of prosthetic valve function by accurately measuring changes in the transvalvular flow fields associated with normal and dysfunctional prosthetic valves. The objectives of these in vitro experiments were to investigate the potential for using MRI as a tool to measure the complex flow fields distal to replacement heart valves, and to assess the accuracy of MRI velocity measurements by comparison with Laser Doppler Anemometry (LDA), a gold standard. The velocity fields downstream of tilting disc, bileaflet, ball and cage, and pericardial tissue valves were measured using both three-component LDA and MRI phase velocity encoding under a steady flow rate of 22.8 l/min, simulating peak systolic flow. The valves were tested under normal and stenotic conditions to assess the MRI capabilities under a wide range of local flow conditions, velocities and turbulence levels. A new short echo time MRI technique (FAcE), which allowed velocity measurements in stenotic jets with high turbulence, was tested. Good overall agreement was obtained between the MRI velocity measurements and the LDA data. The MRI velocity measurements adequately reproduced the spatial structure of the flow fields. In most cases peak velocities were accurately measured to within 15%. The results indicate that the FAcE MRI method has the potential to be used as a diagnostic tool to assess prosthetic valve function.

Automatic fire hydrant valve development

International Nuclear Information System (INIS)

Drumheller, K.

1976-01-01

The development of a remotely-controlled valve to operate a fire hydrant is described. Assembled from off-the-shelf components, the prototype illustrates that a valve light enough to be handled by one man is possible. However, it does not have the ruggedness or reliability needed for actual fire-fighting operations. Preliminary testing by City of Tacoma fire department personnel indicates that the valve may indeed contribute significantly to fire-fighting efficiency

Valve-stem-packing improvement study. Final report

International Nuclear Information System (INIS)

Adey, C.W.; Klein, J.J.

1982-08-01

By employing questionnaires and face-to-face interviews with valve and valve packing manufacturers, as well as nuclear plant personnel, an understanding of valve stem packing leakage problems from each of the three viewpoints was developed. This information, in-house experience, and available technical literature were used to develop specific recommendations for valve manufacturers, valve packing manufacturers, and nuclear plant valve users. It was generally recommended that each these groups make better use of graphite packing. The questionnaires and interviews indicated that increased usage of graphite packing over the last few years has reduced the incidence of valve packing problems. To confirm this, a survey of Licensee Event Reports (LERs) from 1972 to 1980 was undertaken using the keywords Valve and Packing. A statistical analysis of the LER data confirms that the adoption of graphite packing has significantly reduced valve stem leakage

Right ventricular dysfunction following continuous flow left ventriccular assist device placement in 51 patients: predicators and outcomes

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Neragi-Miandoab Siyamek

2012-06-01

Full Text Available Abstract Background Right ventricular (RV dysfunction following implantation of a left ventricular assist device (LVAD is a serious condition and is associated with increased mortality. Methods The aim of the study is to investigate the significance of pre-existing RV dysfunction, tricuspid valve (TV insufficiency, and the severity of septal deviation following LVAD implantation on RV dysfunction, as well as the outcome and short-term complications in 51 patients from June 2006 to August 2010. Student t test was used to compare the data and estimate the p value. Results Mean age was 55.1 ± 13, with a male to female ratio of 3.25. The 30-day mortality was 13.7% (7/51 patients, and the overall mortality was 23.5% (12/51 patients. Meanwhile, 21 patients (21/51; 41.2% have undergone orthotopic heart transplantation. The mean time of support was 314.5±235 days with a median of 240 days at the time of closing this study. Echocardiographic evaluation of RV function pre- and post-implantation of an LVAD demonstrated septal deviation towards the left ventricle in immediate postoperative phase, which correlated with acute RV dysfunction (p = 0.002. Preoperative RV dysfunction was a significant predictor of postoperative right heart dysfunction following implantation of an LVAD (p = 0.001. Conclusion Preoperative RV dysfunction is a predictor of RV failure in LVAD patients. The adjustment of septal deviation through gradual increase of the LVAD flow can prevent the acute RV dysfunction following LVAD placement.

Recent Development in Pulmonary Valve Replacement after Tetralogy of Fallot Repair: The Emergence of Hybrid Approaches

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Tariq eSuleiman

2015-06-01

Full Text Available In the current era approximately 90% of infants born with tetralogy of Fallot (ToF are expected to live beyond 40 years of age making it the fastest growing population amongst patients with congenital heart disease. One of the most common late consequences after repair of ToF, is pulmonary valve regurgitation (PVR. Significant PVR results in progressive dilatation and dysfunction of the right ventricle, decrease in exercise tolerance, arrhythmias, heart failure, and increased risk of sudden death. The conventional approach of dealing with this problem is to perform pulmonary valve replacement using cardiopulmonary bypass (CPB and cardioplegic arrest. However, this approach is associated not only with long operative times but also side effects related to the use of CPB. Development of percutaneous approaches to valve disease is one of the most exciting areas of research and clinical innovation in cardiovascular research. The main development has been that of transcatheter pulmonary valve replacement for the rehabilitation of conduits between the right ventricle and pulmonary artery in patients after surgery for ToF. However, with the percutaneous technique, a limited size of prosthesis can be inserted. Moreover, the technique does not offer the opportunity of treating additional defects that are frequently associated with severe PR, such as pulmonary artery dilatation, and it cannot be used in the significantly dilated native right ventricular outlet tract (RVOT. The advent of the hybrid surgical options for treating cardiac disease has integrated the techniques of interventional cardiology with the techniques of cardiac surgery to provide a form of therapy that combines the respective strengths of both fields.In this review, we present and compare recent advances in procedures to replace the pulmonary valve in patients with ToF presenting with severe PVR and dilated RVOT.

Heart valve surgery

Science.gov (United States)

... replacement; Valve repair; Heart valve prosthesis; Mechanical valves; Prosthetic valves ... surgery. Your heart valve has been damaged by infection ( endocarditis ). You have received a new heart valve ...

Development of an effective valve packing program

Energy Technology Data Exchange (ETDEWEB)

Hart, K.A.

1996-12-01

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

The impact of age on the postoperative response of the diastolic function and left ventricular mass regression after surgical or transcatheter aortic valve replacement for severe aortic stenosis.

Science.gov (United States)

Nakamura, Teruya; Toda, Koichi; Kuratani, Toru; Miyagawa, Shigeru; Yoshikawa, Yasushi; Fukushima, Satsuki; Saito, Shunsuke; Sawa, Yoshiki

2017-06-01

We examined the impact of advanced age on left ventricular mass regression and the change in the diastolic function after aortic valve replacement in patients with aortic stenosis. The present study included 129 patients who underwent either surgical or transcatheter aortic valve replacement and 1-year postoperative echocardiography. The patient characteristics and echocardiographic findings were compared between patients who were regression was significantly greater (p = 0.02) and diastolic dysfunction was less prevalent in group Y (p = 0.02) in comparison to group O. The change in E/e' was significantly correlated with the left ventricular mass regression in group Y (p = 0.02), but not in Group O (p = 0.21). The patients in group O were less susceptible to improvements in myocardial remodeling and the diastolic function in comparison to those in group Y. The altered physiological response to aortic valve replacement might help to determine the appropriate timing of surgery in elderly patients.

Experimental investigation of the fluid dynamic efficiency of a high performance multi-valve internal combustion engine during the intake phase: Influence of valve-valve interference phenomena

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Algieri Angelo

2013-01-01

Full Text Available The purpose of the present work is the analysis of the fluid dynamic behavior of a high performance internal combustion engine during the intake phase. In particular, a four-valve spark-ignition engine has been characterized at the steady flow rig. Dimensionless discharge coefficients have been used to define the global fluid dynamic efficiency of the intake system, while the Laser Doppler Anemometry (LDA technique has been employed to evaluate the mean flow in the valve curtain area and to characterise the interference phenomena between the two intake valves. The investigation has shown the significant influence of the valve lift on the volumetric efficiency of the intake apparatus. Moreover, the experimental analysis has highlighted that the valve-valve interference phenomena have a relevant impact on the head breathability, on the flow development within the combustion chamber and on the velocity standard deviations.

Impact of recipient-related factors on structural dysfunction of xenoaortic bioprosthetic heart valves

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Barbarash O

2015-03-01

Full Text Available Olga Barbarash, Natalya Rutkovskaya, Oksana Hryachkova, Olga Gruzdeva, Evgenya Uchasova, Anastasia Ponasenko, Natalya Kondyukova, Yuri Odarenko, Leonid Barbarash Federal State Budgetary Scientific Institution Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, Russia Objective: To analyze the influence of recipient-related metabolic factors on the rate of structural dysfunction caused by the calcification of xenoaortic bioprostheses. Materials and methods: We retrospectively analyzed clinical status, calcium–phosphorus metabolism, and nonspecific markers of inflammatory response in bioprosthetic mitral valve recipients with calcific degeneration confirmed by histological and electron microscopic studies (group 1, n=22, and in those without degeneration (group 2, n=48. Results: Patients with confirmed calcification of bioprostheses were more likely to have a severe clinical state (functional class IV in 36% in group 1 versus 15% in group 2, P=0.03 and a longer cardiopulmonary bypass period (112.8±18.8 minutes in group 1 versus 97.2±23.6 minutes in group 2, P=0.02 during primary surgery. Patients in group 1 demonstrated moderate hypovitaminosis D (median 34.0, interquartile range [21.0; 49.4] vs 40 [27.2; 54.0] pmol/L, P>0.05, osteoprotegerin deficiency (82.5 [44.2; 115.4] vs 113.5 [65.7; 191.3] pg/mL, P>0.05 and osteopontin deficiency (4.5 [3.3; 7.7] vs 5.2 [4.1; 7.2] ng/mL, P>0.05, and significantly reduced bone-specific alkaline phosphatase isoenzyme (17.1 [12.2; 21.4] vs 22.3 [15.5; 30.5] U/L, P=0.01 and interleukin-8 levels (9.74 [9.19; 10.09] pg/mL vs 13.17 [9.72; 23.1] pg/mL, P=0.045 compared with group 2, with an overall increase in serum levels of proinflammatory markers. Conclusion: Possible predictors of the rate of calcific degeneration of bioprostheses include the degree of decompensated heart failure, the duration and invasiveness of surgery, and the characteristics of calcium–phosphorus homeostasis in

Clinical Significance of the Presence of Autonomic and Vestibular Dysfunction in Diabetic Patients with Peripheral Neuropathy

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Soo Kyoung Kim

2012-02-01

Full Text Available BackgroundWe investigated the prevalence of diabetic autonomic neuropathy (DAN and vestibular dysfunction (VD in diabetic patients with peripheral neuropathy.MethodsThirty-five diabetic patients with peripheral neuropathy were enrolled from August 2008 to July 2009. All subjects underwent autonomic function tests. Nineteen of the patients (54.3% underwent videonystagmography.ResultsDiabetic autonomic neuropathy was observed in 28 patients (80%. A mild degree of autonomic failure was observed in 18 patients (64.3%, and a moderate degree of autonomic failure was observed in ten patients (35.7%. Factors related to DAN included diabetic nephropathy (P=0.032, degree of chronic kidney disease (P=0.003, and duration of diabetes (P=0.044. Vestibular dysfunction was observed in 11 of 19 patients (57.9%. There was no significant association between DAN and VD.ConclusionDiabetic autonomic neuropathy was observed in 28 diabetic patients (80% with peripheral neuropathy. Vestibular dysfunction was observed in nearly 60% of diabetic patients with peripheral neuropathy who complained of dizziness but showed no significant association with DAN. Diabetic patients who complained of dizziness need to examine both autonomic function and vestibular function.

Mechanical versus bioprosthetic aortic valve replacement.

Science.gov (United States)

Head, Stuart J; Çelik, Mevlüt; Kappetein, A Pieter

2017-07-21

Mechanical valves used for aortic valve replacement (AVR) continue to be associated with bleeding risks because of anticoagulation therapy, while bioprosthetic valves are at risk of structural valve deterioration requiring reoperation. This risk/benefit ratio of mechanical and bioprosthetic valves has led American and European guidelines on valvular heart disease to be consistent in recommending the use of mechanical prostheses in patients younger than 60 years of age. Despite these recommendations, the use of bioprosthetic valves has significantly increased over the last decades in all age groups. A systematic review of manuscripts applying propensity-matching or multivariable analysis to compare the usage of mechanical vs. bioprosthetic valves found either similar outcomes between the two types of valves or favourable outcomes with mechanical prostheses, particularly in younger patients. The risk/benefit ratio and choice of valves will be impacted by developments in valve designs, anticoagulation therapy, reducing the required international normalized ratio, and transcatheter and minimally invasive procedures. However, there is currently no evidence to support lowering the age threshold for implanting a bioprosthesis. Physicians in the Heart Team and patients should be cautious in pursuing more bioprosthetic valve use until its benefit is clearly proven in middle-aged patients. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Design And Analysis Of A Camless Valve Mechanism For I.C Engines Using Rotary Disc Valves

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Vivek Jitendra Panchal

2017-09-01

Full Text Available It is the object of the presented paper to provide an electromechanical rotary valve actuating system for opening and closing valves of an internal combustion engine capable of separately controlling both the inlet and exhaust valve operations of each individual cylinder in a multi-cylinder engine. This indicates that only one valve will be required for each cylinder of the engine. Previously published versions of this concept require a separate valve for intake and exhaust in each cylinder. The system provides an alternative to the camshaft assembly in an attempt to overcome the limitations and inadequacies inevitably posed by a fully mechanical system. The prototype development is approached in a theoretical manner beginning with the conceptualization and design of a rotating disk with a notches and corresponding closure surfaces to open and close the flow path. The actuated disk and notch design is then refined and followed by the design of an inlet and exhaust manifold to correspond to the valve design and the theorizing and design of a sealing gasket. The rotating speed of the valve is determined by a general idling speed and can be varied to provide variable valve timing with the motor. The final assembly eliminates a majority of the moving parts currently used in camshaft systems like the cam camshaft rocker arm push rod and springs and results in a significantly lighter valve actuation system. By eliminating the translatory motion of valves the problem of valves slamming on the valve seats at high velocities is eliminated thus greatly reducing engine wear.

Late thrombosis of a mitral bioprosthetic valve with associated massive left atrial thrombus

Directory of Open Access Journals (Sweden)

Preetham R Muskula

2017-04-01

Full Text Available An 84-year-old man presented 5 years after bioprosthetic mitral valve replacement with three months of worsening dyspnea on exertion. A new mitral stenosis murmur was noted on physical examination, and an electrocardiogram revealed newly recognized atrial fibrillation. Severe mitral stenosis (mean gradient = 13 mmHg was confirmed by transthoracic echocardiography. Transesophageal echocardiography revealed markedly thickened mitral bioprosthetic leaflets with limited mobility, and a massive left atrial thrombus (>4 cm in diameter (Fig. 1A, B, C, D and Videos 1, 2, 3 and 4. Intravenous heparin was initiated, and 5 days later, he was taken to the operating room for planned redo mitral valve replacement and left atrial thrombus extraction. Intraoperative transesophageal echocardiography revealed near-complete resolution of the bioprosthetic leaflet thickening, and a mean mitral gradient of only 3 mmHg (Fig. 2A, B, C and Videos 5, 6 and 7. The patient underwent resection of the massive left atrial thrombus (Fig. 2D but did not require redo mitral valve replacement. He was initiated on heparin (and transitioned to warfarin early in the post-operative period, with complete resolution of dyspnea on exertion at 3-month follow-up. Bioprosthetic valve thrombosis is increasingly recognized as a cause of early prosthetic valve dysfunction (1, 2. This case illustrates that bioprosthetic valve thrombosis may occur years after valve replacement; therefore, any deterioration in a patient’s clinical status (new-onset dyspnea, heart failure or atrial fibrillation warrants a thorough evaluation of the bioprosthetic valve with transesophageal echocardiography. In this case, initiation of anticoagulation obviated the need for redo mitral valve replacement.

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

Science.gov (United States)

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.

Minimally invasive aortic valve replacement

DEFF Research Database (Denmark)

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

2009-01-01

In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy...... operations were completed as mini-sternotomies, 4 died later of noncardiac causes. The aortic cross-clamp and perfusion times were significantly different across all groups (P replacement...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

Long-term results of percutaneous balloon valvuloplasty in pulmonary valve stenosis in the pediatric population.

Science.gov (United States)

Merino-Ingelmo, Raquel; Santos-de Soto, José; Coserria-Sánchez, Félix; Descalzo-Señoran, Alfonso; Valverde-Pérez, Israel

2014-05-01

Percutaneous pulmonary valvuloplasty is the preferred interventional procedure for pulmonary valve stenosis. The aim of this study was to evaluate the effectiveness of this technique, assess the factors leading to its success, and determine the long-term results in the pediatric population. The study included 53 patients with pulmonary valve stenosis undergoing percutaneous balloon valvuloplasty between December 1985 and December 2000. Right ventricular size and functional echocardiographic parameters, such as pulmonary regurgitation and residual transvalvular gradient, were assessed during long-term follow-up. Peak-to-peak transvalvular gradient decreased from 74 mmHg [interquartile range, 65-100 mmHg] to 20 mmHg [interquartile range, 14-34 mmHg]. The procedure was unsuccessful in 2 patients (3.77%). The immediate success rate was 73.58%. Follow-up ranged from 10 years to 24 years (median, 15 years). During follow-up, all patients developed late pulmonary regurgitation which was assessed as grade II in 58.4% and grade III in 31.2%. There was only 1 case of long-term restenosis (2.1%). Severe right ventricular dilatation was observed in 27.1% of the patients. None of the patients developed significant right ventricular dysfunction. Pulmonary valve replacement was not required in any of the patients. Percutaneous balloon valvuloplasty is an effective technique in the treatment of pulmonary valve stenosis with good long-term results. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

Multifunctional four-port directional control valve constructed from logic valves

International Nuclear Information System (INIS)

Lisowski, E.; Czyżycki, W.; Rajda, J.

2014-01-01

Highlights: • Directional valve with standard ISO 440-08 has been constructed from logic valves. • Only one innovative valve may replace whole family of the standard valves. • CFD analysis and bench tests of the innovative valve has been carried. • Parameters of the innovative valve are equaling or surpassing the standard ones. • The innovative valve has additional possibilities of pressure and flow control. - Abstract: The paper refers to four-port solenoid pilot operated valves, which are subplate mounted in a hydraulic system in accordance with the ISO 4401 standard. Their widespread use in many machines and devices causes a continuing interest in the development of their design by both the scientific centers and the industry. This paper presents an innovative directional control valve based on the use of logic valves and a methodology followed for the design of it by using Solid Edge CAD and ANSYS/Fluent CFD software. The valve design methodology takes into account the need to seek solutions that minimize flow resistance through the valve. For this purpose, the flow paths are prepared by means of CAD software and pressure-flow curves are determined as a result of CFD analysis. The obtained curves are compared with the curves available in the catalogs of spool type directional control valves. The new solution allows to replace the whole family of spool type four-port directional control valves by one valve built of logic valves. In addition, the innovative directional control valve provides leak-proof shutting the flow paths off and also it can control flow rate and even pressure of working liquid. A prototype of the valve designed by the presented method has been made and tested on the test bench. The results quoted in the paper confirm that the developed logic type directional control valve is able to meet all designed connection configurations, and the obtained pressure-flow curves show very good conformity with the results of CFD analysis

Control Valve

Energy Technology Data Exchange (ETDEWEB)

Moore, Wayne R.

2018-03-20

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 a 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.

Biofilm formation on the Provox ActiValve: Composition and ingrowth analyzed by Illumina paired-end RNA sequencing, fluorescence in situ hybridization, and confocal laser scanning microscopy.

Science.gov (United States)

Timmermans, Adriana J; Harmsen, Hermie J M; Bus-Spoor, Carien; Buijssen, Kevin J D A; van As-Brooks, Corina; de Goffau, Marcus C; Tonk, Rudi H; van den Brekel, Michiel W M; Hilgers, Frans J M; van der Laan, Bernard F A M

2016-04-01

The most frequent cause of voice prosthesis failure is microbial biofilm formation on the silicone valve, leading to destruction of the material and transprosthetic leakage. The Provox ActiValve valve is made of fluoroplastic, which should be insusceptible to destruction. The purpose of this study was to determine if fluoroplastic is insusceptible to destruction by Candida species. Thirty-three dysfunctional Provox ActiValves (collected 2011-2013). Biofilm analysis was performed with Illumina paired-end sequencing (IPES), assessment of biofilm-material interaction with fluorescence in situ hybridization (FISH), and confocal laser scanning microscopy (CLSM). IPES (n = 10) showed that Candida albicans and Candida tropicalis are dominant populations on fluoroplastic and silicone. Microbial diversity is significantly lower on fluoroplastic. Lactobacillus gasseri is the prevalent bacterial strain on most voice prostheses. FISH and CLSM (n = 23): in none of the cases was ingrowth of Candida species present in the fluoroplastic. Fluoroplastic material of Provox ActiValve seems insusceptible to destruction by Candida species, which could help improve durability of voice prostheses. © 2015 Wiley Periodicals, Inc. Head Neck 38: E432-E440, 2016. © 2015 Wiley Periodicals, Inc.

Non intrusive check valve diagnostics at Bruce A

International Nuclear Information System (INIS)

Marsch, S.P.

1997-01-01

Bruce A purchased non intrusive check valve diagnostic equipment in 1995 to ensure operability and availability of critical check valves in the Station. Diagnostics can be used to locate and monitor check valve degradation modes. Bruce A initiated a pilot program targeting check valves with flow through them and ones that completed open or close cycles. Approaches to determine how to confirm operability of passive check valves using non intrusive techniques were explored. A sample population of seventy-three check valves was selected to run the pilot program on prior to complete implementation. The pilot program produced some significant results and some inconclusive results. The program revealed a major finding that check valve performance modeling is required to ensure continuous operability of check valves. (author)

Non intrusive check valve diagnostics at Bruce A

Energy Technology Data Exchange (ETDEWEB)

Marsch, S.P. [Ontario Hydro, Bruce Nuclear Generating Station A, Tiverton, ON (Canada)

1997-07-01

Bruce A purchased non intrusive check valve diagnostic equipment in 1995 to ensure operability and availability of critical check valves in the Station. Diagnostics can be used to locate and monitor check valve degradation modes. Bruce A initiated a pilot program targeting check valves with flow through them and ones that completed open or close cycles. Approaches to determine how to confirm operability of passive check valves using non intrusive techniques were explored. A sample population of seventy-three check valves was selected to run the pilot program on prior to complete implementation. The pilot program produced some significant results and some inconclusive results. The program revealed a major finding that check valve performance modeling is required to ensure continuous operability of check valves. (author)

Limitations of multimodality imaging in the diagnosis of pannus formation in prosthetic aortic valve and review of the literature.

Science.gov (United States)

Soumoulou, Juan Bautista; Cianciulli, Tomás Francisco; Zappi, Andrea; Cozzarin, Alberto; Saccheri, María Cristina; Lax, Jorge Alberto; Guidoin, Robert; Zhang, Ze

2015-04-26

Pannus formation is a rare complication and occurs almost exclusively in mechanical prosthetic valves. It consists of fibrous tissue that covers the surface of the prosthesis either concentrically or eccentrically, resulting in valve dysfunction. The pathophysiology seems to be associated to a chronic inflammatory process that explains the late and insidious clinical presentation. This diagnosis should be considered in patients with high transvalvular gradients on transthoracic echo, and workup should be completed with fluoroscopy and transesophageal echocardiography. Treatment is always surgical and recurrence is rare. We present a case of pannus formation in a prosthetic aortic valve and a review of the literature regarding this disorder.

Posterior urethral valves: Morphological normalization of posterior urethra after fulguration is a significant factor in prognosis.

Science.gov (United States)

Menon, Prema; Rao, K L N; Vijaymahantesh, S; Kanojia, R P; Samujh, R; Batra, Y K; Sodhi, K S; Saxena, A K; Bhattacharya, A; Mittal, B R

2010-07-01

To assess the changes in urethral morphology 3 months post fulguration of posterior urethral valves (PUVs) on micturating cystourethrogram (MCUG) and correlate these changes with the overall clinical status of the patient. A total of 217 children, managed for PUVs during a period of 6 years in a single surgical unit were prospectively studied. The ratio of the diameters of the prostatic and bulbar urethras (PU/BU) was calculated on the pre- and post-fulguration MCUG films. They were categorized into three groups based on the degree of normalization of posterior urethra (post-fulguration PU/BU ratio). Of the 133 patients, 131 had normal urinary stream and 4 (3%) had nocturnal enuresis. Vesicoureteral reflux (VUR), initially seen in 83 units (31% units), regressed completely at a mean duration of 6 months in 41 units (49%). Of the 152 non-VUR, hydroureteronephrosis (HUN) units, 11 were poorly functioning kidneys. Persistent slow but unobstructed drainage was seen in 23 units (16%) over a period of 1.5-5 years (mean 2.5 years). Group B: All the 11 patients had a normal stream. Four (36.4%) had daytime frequency for a mean duration of 1 year and one (9%) had nocturnal enuresis for 1 year. Grade IV-V VUR was seen in five patients (three bilateral), which regressed completely by 3 months in five units (62.5%). In the non-VUR, HUN patients, slow (but unobstructed) drainage was persistent in two units (14%) at 3 years. Group C: Of the 16 patients, only 5 (31.3%) were asymptomatic. Six patients (nine units) had persistent VUR for 6 months to 3 years. Of the 20 units with HUN, 17 (85%) were persistent at 1-4 years (mean 2 years). Eight patients (50%) required a second fulguration while 3 (18.7%) required urethral dilatation for stricture following which all parameters improved. Adequacy of fulguration should be assessed by a properly performed MCUG. A postop PU/BU ratio >3 SD (1.92) should alert to an incomplete fulguration or stricture. Patients within normal range ratio

Left atrial volume index as a predictor for persistent left ventricular dysfunction after aortic valve surgery in patients with chronic aortic regurgitation: the role of early postoperative echocardiography.

Science.gov (United States)

Cho, In-Jeong; Chang, Hyuk-Jae; Hong, Geu-Ru; Heo, Ran; Sung, Ji Min; Lee, Sang-Eun; Chang, Byung-Chul; Shim, Chi Young; Ha, Jong-Won; Chung, Namsik

2015-06-01

This study aimed to explore whether echocardiographic measurements during the early postoperative period can predict persistent left ventricular systolic dysfunction (LVSD) after aortic valve surgery in patients with chronic aortic regurgitation (AR). We prospectively recruited 54 patients (59 ± 12 years) with isolated chronic severe AR who subsequently underwent aortic valve surgery. Standard transthoracic echocardiography was performed before the operation, during the early postoperative period (≤2 weeks), and then 1 year after the surgery. Twelve patients with preoperative LVSD demonstrated LVSD at early after the surgery. Of the 42 patients without LVSD at preoperative echocardiography, 15 patients (36%) developed early postoperative LVSD after surgical correction. All 27 patients without LVSD at early postoperative echocardiography maintained LV function at 1 year after surgery. In the other 27 patients with postoperative LVSD, 17 patients recovered from LVSD and 10 patients did not at 1 year after surgery. Multiple logistic analysis demonstrated that postoperative left atrial volume index (LAVI) was the only independent predictor for persistent LVSD at 1 year after surgery in patients with postoperative LVSD (OR 1.180, 95% CI, 1.003-1.390, P = 0.046). The optimal LAVI cutoff value (>34.9 mL/m(2) ) had a sensitivity of 80% and a specificity of 88% for the prediction of persistent LVSD. Prevalence of early postoperative LVSD was relatively high, even in the patients without LVSD at preoperative echocardiography. Postoperative LAVI could be useful to predict persistent LVSD after aortic valve surgery in patients with early postoperative LVSD. © 2014, Wiley Periodicals, Inc.

Prospective ECG triggering reduces prosthetic heart valve-induced artefacts compared with retrospective ECG gating on 256-slice CT

NARCIS (Netherlands)

Symersky, P.; Habets, J.; Westers, P.; Mol, de B.A.J.M.; Prokop, M.; Budde, R.P.J.

2012-01-01

Objectives Multidetector computed tomography (MDCT) has diagnostic value for the evaluation of prosthetic heart valve (PHV) dysfunction but it is hampered by artefacts. We hypothesised that image acquisition using prospective triggering instead of retrospective gating would reduce artefacts related

Retrieval of a leaflet escaped in a Tri-technologies bileaflet mechanical prosthetic valve.

Science.gov (United States)

Cianciulli, Tomás F; Lax, Jorge A; Saccheri, María C; Guidoin, Robert; Salvado, César M; Fernández, Adrián J; Prezioso, Horacio A

2008-01-01

The escape of the prosthetic heart valve disc is one of the causes of prosthetic dysfunction that requires emergency surgery. The removal of the embolized disc should be carried out because of the risk of a progressive extrusion on the aortic wall. Several imaging techniques can be used for the detection of the missing disc localization. In this report we describe a 32-year-old man who underwent mitral valve replacement with a Tri-technologies bileaflet valve three years ago, and was admitted in cardiogenic shock. Transesophageal echocardiography showed acute-onset massive mitral regurgitation. The patient underwent emergency replacement of the prosthetic valve. Only one of the two leaflets remained in the removed prosthetic valve. The missing leaflet could not be found within the cardiac cavity. The abdominal fluoroscopic study and plain radiography were unable to detect the escaped leaflet. The abdominal computed tomography scan and the ultrasound showed the escaped leaflet in the terminal portion of the aortic bifurcation. To retrieve the embolized disc laparotomy and aortotomy were performed three months later. The escaped leaflet shows a fracture of one of the pivot systems caused by structural failure. This kind of failure mode is usually the result of high stress concentration.

First report on a human percutaneous transluminal implantation of a self-expanding valve prosthesis for interventional treatment of aortic valve stenosis.

Science.gov (United States)

Grube, Eberhard; Laborde, Jean C; Zickmann, Bernfried; Gerckens, Ulrich; Felderhoff, Thomas; Sauren, Barthel; Bootsveld, Andreas; Buellesfeld, Lutz; Iversen, Stein

2005-12-01

Percutaneous aortic valve replacement is a new technology for the treatment of patients with significant aortic valve stenosis. We present the first report on a human implantation of a self-expanding aortic valve prosthesis, which is composed of three bovine pericardial leaflets inserted within a self-expanding nitinol stent. The 73-year-old woman presented with severe symptomatic aortic valve stenosis (mean transvalvular gradient of 45 mmHg; valve area of 0.7 cm2). Surgical valve replacement had been declined for the patient because of comorbidities, including previous bypass surgery. A retrograde approach via the common iliac artery was used for valve deployment. The contralateral femoral vessels were used for a temporary extracorporal circulation, unloading the left ventricle during the actual stent expansion. Clinical, hemodynamic, and echocardiographic outcomes were assessed serially during the procedure. Clinical and echocardiographic follow-up at day 1, 2, and 14 post procedure was performed to evaluate the short-term outcome. The prosthesis was successfully deployed within the native aortic valve, with accurate and stable positioning and with no impairment of the coronary artery or vein graft blood flow. 2D and doppler echo immediately after device deployment showed a significant reduction in transaortic mean pressure gradient (from 45 to 8 mmHg) without evidence of aortic or mitral valve insufficiency. The clinical status has then significantly improved. These results remained unchanged up to the day 14 follow-up. This case report demonstrates a successful percutaneous implantation of a self-expanding aortic valve prosthesis with remarkable functional and clinical improvements in the acute and short-term outcome. Copyright (c) 2005 Wiley-Liss, Inc.

Dilatation and Dysfunction of the Neo-aortic Root and in 76 Patients After the Ross Procedure.

Science.gov (United States)

Zimmermann, Corina A; Weber, Roland; Greutmann, Matthias; Dave, Hitendu; Müller, Christoph; Prêtre, René; Seifert, Burkhardt; Buechel, Emanuela Valsangiacomo; Kretschmar, Oliver; Attenhofer Jost, Christine H

2016-08-01

Pulmonary autograft replacement (Ross procedure) is used as an alternative to prosthetic aortic valve replacement patients with aortic valve disease. There are limited data on incidence and risk factors for dilatation and dysfunction of the neo-aortic after the Ross procedure. Ross procedure was performed in 100 patients at our institution between 1993 and 2011. In 76 patients, complete follow-up data were available. Their median age at surgery was 16 (0.4-58) years (76 % males; 95 % with congenital aortic valve disease). Median follow-up duration was 5.2 years (0.3-16.0 years). We analyzed their clinical and echocardiographic follow-up to identify possible risk factors for neo-aortic root dilatation and dysfunction. Ross procedure included reduction plasty of the native ascending aorta in 25 % of patients. During follow-up, 21 patients (28 %) developed neo-aortic root dilatation, 38 patients (50 %) dilatation oft the native ascending aorta and 7 patients (9 %) at least moderate neo-aortic regurgitation. Univariate risk factors for neo-aortic root dilatation were preoperative aortic regurgitation (p = 0.04), concomitant reduction plasty of the ascending aorta (p = 0.009) and a longer duration of follow-up (p = 0.005). Younger age at surgery was associated with dilatation of the ascending aorta (p = 0.03). Reoperation on the neo-aortic root because of severe dilatation was necessary in 6 patients (8 %), where 2 patients had at least moderate neo-aortic root regurgitation. Neo-aortic root and aortic dilatation are common after the Ross procedure. This is often combined with neo-aortic valve dysfunction. Close follow-up of these patients is mandatory.

Baseline MDCT findings after prosthetic heart valve implantation provide important complementary information to echocardiography for follow-up purposes

Energy Technology Data Exchange (ETDEWEB)

Sucha, Dominika; Mali, Willem P.T.M.; Habets, Jesse [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Chamuleau, Steven A.J. [University Medical Center Utrecht, Department of Cardiology, Utrecht (Netherlands); Symersky, Petr [VU Medical Center, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); Meijs, Matthijs F.L. [Thoraxcentrum Twente, Medisch Spectrum Twente, Department of Cardiology, Enschede (Netherlands); Brink, Renee B.A. van den [Academic Medical Center, Department of Cardiology, Amsterdam (Netherlands); Mol, Bas A.J.M. de [Academic Medical Center, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); Herwerden, Lex A. van [University Medical Center Utrecht, Department of Cardiothoracic Surgery, Utrecht (Netherlands); Budde, Ricardo P.J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands)

2016-04-15

Recent studies have proposed additional multidetector-row CT (MDCT) for prosthetic heart valve (PHV) dysfunction. References to discriminate physiological from pathological conditions early after implantation are lacking. We present baseline MDCT findings of PHVs 6 weeks post implantation. Patients were prospectively enrolled and TTE was performed according to clinical guidelines. 256-MDCT images were systematically assessed for leaflet excursions, image quality, valve-related artefacts, and pathological and additional findings. Forty-six patients were included comprising 33 mechanical and 16 biological PHVs. Overall, MDCT image quality was good and relevant regions remained reliably assessable despite mild-moderate PHV-artefacts. MDCT detected three unexpected valve-related pathology cases: (1) prominent subprosthetic tissue, (2) pseudoaneurysm and (3) extensive pseudoaneurysms and valve dehiscence. The latter patient required valve surgery to be redone. TTE only showed trace periprosthetic regurgitation, and no abnormalities in the other cases. Additional findings were: tilted aortic PHV position (n = 3), pericardial haematoma (n = 3) and pericardial effusion (n = 3). Periaortic induration was present in 33/40 (83 %) aortic valve patients. MDCT allowed evaluation of relevant PHV regions in all valves, revealed baseline postsurgical findings and, despite normal TTE findings, detected three cases of unexpected, clinically relevant pathology. (orig.)

Mitral Valve Disease

Science.gov (United States)

... for mitral valve replacement—mechanical valves (metal) or biological valves (tissue). The principal advantage of mechanical valves ... small risk of stroke due to blood clotting. Biological valves usually are made from animal tissue. Biological ...

Results of aortic valve repair using decellularized bovine pericardium in congenital surgery.

Science.gov (United States)

Nordmeyer, Sarah; Murin, Peter; Schulz, Antonia; Danne, Friederike; Nordmeyer, Johannes; Kretzschmar, Johanna; Sumbadze, Daria; Schmitt, Katharina Rose Luise; Miera, Oliver; Cho, Mi-Young; Sinzobahamvya, Nicodeme; Berger, Felix; Ovroutski, Stanislav; Photiadis, Joachim

2018-04-30

The search for an optimal patch material for aortic valve reconstruction (AVR) is an ongoing challenge. In this study, we report our experience of AVR using decellularized bovine pericardial patch material in congenital heart surgery. Data of 40 consecutive patients who underwent AVR using the CardioCel® patch (Admedus Regen Pty Ltd, Perth, WA, Australia) between February 2014 and August 2016 were retrospectively reviewed. The median age of the patients at operation was 9 (2-34) years, and 18 patients were younger than 7 years. Twenty-six patients initially presented with aortic valve insufficiency (AI) and 14 with stenosis. Clinical and echocardiographic data were available until August 2017 for a median postoperative follow-up (FU) of 22 (6-42) months. Nine of 40 (23%) patients experienced an event during FU (death: n = 1, 2.5%; reoperation: n = 8, 20%). Overall, the probability of freedom from reoperation or death was 97 ± 3%, 76 ± 9% and 57 ± 12% at 12, 24 and 36 months of FU, respectively. Reason for reoperation was stenosis in 3 (37.5%) patients, insufficiency in 4 (50%) patients and 1 (12.5%) patient was diagnosed with aortic valve endocarditis. Of the remaining 31 patients, 2 patients are scheduled for reoperation (aortic valve stenosis: n = 1 and AI: n = 1) and 9 patients exhibit worsening of aortic valve function with moderate AI. Freedom from developing combined end point [death/reoperation/moderate degree of aortic valve dysfunction (aortic valve stenosis, AI)] after AVR was 92 ± 5%, 55 ± 9% and 28 ± 9% at 12, 24 and 36 months, respectively. AVR using decellularized bovine pericardial patch material in patients with congenital aortic valve disease show unsatisfactory results within the first 3 years of FU.

Review and analysis of check valve failure data

International Nuclear Information System (INIS)

Todd, M.D.; Casada, D.A.

1992-01-01

Check valve operating problems in recent years have resulted in significant operating transients, increased cost and decreased system availability. There has been, in response, additional attention given to check valves by utilities, as well as the US Nuclear Regulatory Commission and the American Society of Mechanical Engineers Operation and Maintenance Committee. All these organizations have the fundamental goal of ensuring reliable operation of check valves. A key ingredient to an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. Oak Ridge National Laboratory is currently conducting a detailed review of historical failure data available through the Institute of Nuclear Power Operation's Nuclear Plant Reliability Data System. The focus of the review is on check valve failures that have involved significant degradation of the valve internal parts. A variety of parameters are being considered during the review, including size, age, system of service, method of failure discovery, the affected valve parts, attributed causes, and corrective actions

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

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-01

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

Tight valve

International Nuclear Information System (INIS)

Guedj, F.

1987-01-01

This sealed valve is made with a valve seat, an axial valve with a rod fixed to its upper end, a thick bell surrounding the rod and welded by a thin join on the valve casing, a threated ring screwed onto the upper end of the rod and a magnet or electromagnet rotating the ring outside the bell [fr

Changes in Left Ventricular Morphology and Function After Mitral Valve Surgery

Science.gov (United States)

Shafii, Alexis E.; Gillinov, A. Marc; Mihaljevic, Tomislav; Stewart, William; Batizy, Lillian H.; Blackstone, Eugene H.

2015-01-01

Degenerative mitral valve disease is the leading cause of mitral regurgitation in North America. Surgical intervention has hinged on symptoms and ventricular changes that develop as compensatory ventricular remodeling takes place. In this study, we sought to characterize the temporal response of left ventricular (LV) morphology and function to mitral valve surgery for degenerative disease, and identify preoperative factors that influence reverse remodeling. From 1986–2007, 2,778 patients with isolated degenerative mitral valve disease underwent valve repair (n=2,607/94%) or replacement (n=171/6%) and had at least 1 postoperative transthoracic echocardiogram (TTE); 5,336 TTEs were available for analysis. Multivariable longitudinal repeated-measures analysis was performed to identify factors associated with reverse remodeling. LV dimensions decreased in the first year after surgery (end-diastolic from 5.7±0.80 to 4.9±1.4 cm; end-systolic from 3.4±0.71 to 3.1±1.4 cm). LV mass index decreased from 139±44 to 112±73 g·m−2. Reduction of LV hypertrophy was less pronounced in patients with greater preoperative left heart enlargement (P.2). In conclusion, a positive response toward normalization of LV morphology and function after mitral valve surgery is greatest in the first year. The best response occurs when surgery is performed before left heart dilatation, LV hypertrophy, or LV dysfunction develop. PMID:22534055

Small sodium valve design and operating experience

International Nuclear Information System (INIS)

McGough, C.B.

1974-01-01

The United States Liquid Metal Fast Breeder Reactor program (LMFBR) includes an extensive program devoted to the development of small sodium valves. This program is now focused on the development and production of valves for the Fast Flux Test Facility (FFTF) now under construction near Richland, Washington. Other AEC support facilities, such as various test loops located at the Liquid Metal Engineering Center (LMEC), Los Angeles, California, and at the Hanford Engineering Development Laboratory (HEDL), Richland, Washington, also have significant requirements for small sodium valves, and valves similar in design to the FFTF valves are being supplied to these AEC laboratories for use in their critical test installations. A principal motivation for these valve programs, beyond the immediate need to provide high-reliability valves for FFTF and the support facilities, is the necessity to develop small valve technology for the Clinch River Breeder Reactor Plant (CRBRP). FFTF small sodium valve design and development experience will be directly applied to the CRBRP program. Various test programs have been, and are being, conducted to verify the performance and integrity of the FFTF valves, and to uncover any potential problems so that they can be corrected before the valves are placed in service in FFTF. The principal small sodium valve designs being utilized in current U.S. programs, the test and operational experience obtained to date on them, problems uncovered, and future development and testing efforts being planned are reviewed. The standards and requirements to which the valves are being designed and fabricated, the valve designs in current use, valve operators, test and operating experience, and future valve development plans are summarized. (U.S.)

Aortic valve bypass

DEFF Research Database (Denmark)

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

2013-01-01

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

A STUDY OF INDICATIONS, COMPLICATIONS OF PROSTHETIC VALVES AND PROGNOSIS AFTER TREATMENT OF STUCK VALVE

Directory of Open Access Journals (Sweden)

Y. V. Subba Reddy

2017-03-01

Full Text Available BACKGROUND Implantation of prosthetic cardiac valves to treat haemodynamically significant valvular diseases has become common; however, it is associated with complications. Thus, this study was intended to evaluate the indications for implantation of prosthetic valve and complications after its implantation and prognosis after treatment of one of its complication, i.e. stuck valve. MATERIALS AND METHODS This was a single-centered study wherein 50 patients who came to the emergency department with stuck valve were assessed. The 2D echocardiography was performed in all patients. Thrombolysis was done and the gradients were reassessed. Further response to treatment and development of complications before and after treatment were observed. RESULTS Of total patients, 60% were females. Mean age group was 30-40 yrs. Most of them were asymptomatic for 6 years and there was lack of compliance in 90% of patients. Most common indication for valve replacement was mitral stenosis (60% followed by mitral regurgitation (20%, aortic regurgitation and aortic stenosis (10% and combined mitral and tricuspid regurgitation (10%. Commonest valve was St. Jude (90%. Pannus was observed in 10% patients and thrombus was observed in 50% patients. Most patients had gradients 45/20 mmHg across mitral valve. In about 90% patients, gradients decreased after thrombolysis (12/5 mmHg. The complications after thrombolysis were hemiparesis (4%, death before thrombolysis (6% and death after thrombolysis (4%. CONCLUSION Considering these results, it can be concluded that prosthetic valves are seldom associated with some complications. Further, thrombolysis can be effective in patients with prosthetic valve thrombosis.

Building valve amplifiers

CERN Document Server

Jones, Morgan

2013-01-01

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

[Directions for reoperation of patients with Björk-Shiley convexo-concave valve prosthesis, based on long-term experience].

Science.gov (United States)

Yamaki, F; Nakano, K; Endo, M; Hashimoto, A; Koyanagi, H

1994-02-01

Although a high incidence of strut fracture of the Björk-Shiley convexo-concave (C-C) valve prosthesis has been reported, it is still controversial whether the prosthesis functioning normally should be replaced electively. To clarify our policy for this issue, we reviewed 28 patients who had undergone mitral valve replacement with a C-C valve prosthesis, and evaluated long-term results according to STS guidelines. The incidence of valve-related complications expressed as % patient-year were; structural deterioration 0.30, nonstructural dysfunction 0.30, thromboembolism 1.20. There were no thrombosed valves, anticoagulant-related hemorrhage or prosthetic valve endocarditis. The actuarial free rate after valve replacement with the C-C at 10 years, constructed by the Kaplan-Meier method, were compared with those with St. Jude Medical (SJM) valve prosthesis. (1) Actuarial survival: 77.9 vs 87.3 (NS), (2) Reoperation-free: 91.6 vs 98.0 (p valve-related complications: 71.2 vs 77.7 (NS). The long-term results with the C-C were compatible to those with a SJM valve prosthesis. However, if a strut fracture occurs, it is very difficult to save the patient's life. The hospital mortality of re-replacement of valve prosthesis during the last 10 years, at our institute, was 2.6%, which is almost equal to the cumulative risk of strut fracture of the C-C valve after 10 years (3.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Rheumatic Heart Disease and Myxomatous Degeneration: Differences and Similarities of Valve Damage Resulting from Autoimmune Reactions and Matrix Disorganization.

Science.gov (United States)

Martins, Carlo de Oliveira; Demarchi, Lea; Ferreira, Frederico Moraes; Pomerantzeff, Pablo Maria Alberto; Brandao, Carlos; Sampaio, Roney Orismar; Spina, Guilherme Sobreira; Kalil, Jorge; Cunha-Neto, Edecio; Guilherme, Luiza

2017-01-01

Autoimmune inflammatory reactions leading to rheumatic fever (RF) and rheumatic heart disease (RHD) result from untreated Streptococcus pyogenes throat infections in individuals who exhibit genetic susceptibility. Immune effector mechanisms have been described that lead to heart tissue damage culminating in mitral and aortic valve dysfunctions. In myxomatous valve degeneration (MXD), the mitral valve is also damaged due to non-inflammatory mechanisms. Both diseases are characterized by structural valve disarray and a previous proteomic analysis of them has disclosed a distinct profile of matrix/structural proteins differentially expressed. Given their relevance in organizing valve tissue, we quantitatively evaluated the expression of vimentin, collagen VI, lumican, and vitronectin as well as performed immunohistochemical analysis of their distribution in valve tissue lesions of patients in both diseases. We identified abundant expression of two isoforms of vimentin (45 kDa, 42 kDa) with reduced expression of the full-size protein (54 kDa) in RHD valves. We also found increased vitronectin expression, reduced collagen VI expression and similar lumican expression between RHD and MXD valves. Immunohistochemical analysis indicated disrupted patterns of these proteins in myxomatous degeneration valves and disorganized distribution in rheumatic heart disease valves that correlated with clinical manifestations such as valve regurgitation or stenosis. Confocal microscopy analysis revealed a diverse pattern of distribution of collagen VI and lumican into RHD and MXD valves. Altogether, these results demonstrated distinct patterns of altered valve expression and tissue distribution/organization of structural/matrix proteins that play important pathophysiological roles in both valve diseases.

Transcatheter aortic valve implantation in failed bioprosthetic surgical valves

DEFF Research Database (Denmark)

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

2014-01-01

for patients with structural valve deterioration; however, a comprehensive evaluation of survival after the procedure has not yet been performed. OBJECTIVE: To determine the survival of patients after transcatheter valve-in-valve implantation inside failed surgical bioprosthetic valves. DESIGN, SETTING......, stroke, and New York Heart Association functional class. RESULTS: Modes of bioprosthesis failure were stenosis (n = 181 [39.4%]), regurgitation (n = 139 [30.3%]), and combined (n = 139 [30.3%]). The stenosis group had a higher percentage of small valves (37% vs 20.9% and 26.6% in the regurgitation...... and combined groups, respectively; P = .005). Within 1 month following valve-in-valve implantation, 35 (7.6%) patients died, 8 (1.7%) had major stroke, and 313 (92.6%) of surviving patients had good functional status (New York Heart Association class I/II). The overall 1-year Kaplan-Meier survival rate was 83...

Etiologic significance of enlargement of the left atrial appendage in adults

International Nuclear Information System (INIS)

Green, C.E.; Kelley, M.J.; Higgins, C.B.

1982-01-01

Fifty-one patients were divided into two groups: 20 patients with proven rheumatic mitral valve disease (RMVD) and 31 patients with left atrial enlargement (LAE) of a nonrheumatic etiology. The latter group included patients with ischemic papillary muscle dysfunction, mitral valve prolapse, and congestive cardiomyopathy. Radiographic studies showed that enlargement of the left atrial appendage (LAAE) was present in 18 of 20 rheumatics but in only one of 31 nonrheumatics. There was no direct relationship between enlargement of the LAA and radiographic or echocardiographic left atrial size, degree of pulmonary venous hypertension (PVH), or presence of atrial fibrillation. It is postulated that rheumatic influammation of the LAA allows it to dilate out of proportion to the body of the left atrium. In the adult patient with radiographic findings of PVH, LAAE is a valuable and specific radiographic sign of rheumatic mitral valve disease

Experimental substantiation of the design of a prosthetic heart valve for «valve-in-valve» implantation

Directory of Open Access Journals (Sweden)

K. Yu. Klyshnikov

2017-01-01

Full Text Available The aim of the study was to perform a series of in vitro tests of a prototype of the developing heart valve prosthesis to evaluate its functional characteristics. Materials and methods. In this work we have used the frames and full prototypes of the prosthesis, consisting of a stent-like stainless steel support frame with mounted biological leaflets and cover. The authors evaluated the calculated and experimental forces necessary for the displacement of the sutureless implanted prosthesis using the test machine under uniaxial tension. The risk of defects and damages to the supporting framework as a result of implantation was evaluated by scanning electron microscopy. The hydrodynamic characteristics of the prosthesis were investigated under physiological conditions and «valvein-valve» implantation. Evaluation of the ergonomics and applicability of the proposed construction on the cadaver heart model of cattle was carried out. Results. As a result of the forces assessment, it was found that the force required to shear the prosthesis was 3.12 ± 0.37 N, while the calculated value was 1.7 N, which is significantly lower than the obtained value. The comparison of the images obtained with small and large magnifications demonstrated the absence of critical surface defects. Additional analysis under the super-large magnifications also did not reveal problem areas. During the hydrodynamic study, it was shown that the average transplant gradient increased slightly from 2.8–3.4 to 3.2–4.5 mm Hg for the initial prosthesis and the «valve-in-valve» complex, respectively. The decrease of the effective orifice area was 6–9% relative to the initial one. Evaluation of the implantation technique demonstrated the consistency of the approach: the use of the developed holder in combination with the balloon implantation system made it possible to position the prosthesis throughout the procedure. Conclusion. The series of tests demonstrates the consistency

Valve-sparing and valve-replacing techniques for aortic root replacement in patients with Marfan syndrome: Analysis of early outcome.

Science.gov (United States)

Volguina, Irina V; Miller, D Craig; LeMaire, Scott A; Palmero, Laura C; Wang, Xing Li; Connolly, Heidi M; Sundt, Thoralf M; Bavaria, Joseph E; Dietz, Harry C; Milewicz, Dianna M; Coselli, Joseph S

2009-05-01

A prospective, international registry study was initiated to provide contemporary comparative data on short-term clinical outcomes after aortic valve-sparing and aortic valve-replacing root operations in patients with Marfan syndrome. The purpose of this initial report is to describe the study design and to compare early outcomes in the first 151 enrolled patients. We assessed 30-day outcomes in 151 patients who met strict Ghent diagnostic criteria for Marfan syndrome and underwent aortic root replacement with either valve-replacing (n = 46) or valve-sparing techniques (n = 105) at one of 18 participating centers. In the valve replacement group, a mechanical composite valve graft was used in 39 (85%) patients and a bioprosthetic valve in 7 (15%). In the valve-sparing group, David V procedures were performed in 57 (54%) patients, David I in 38 (36%), David IV in 8 (8%), Florida sleeve in 1 (1%), and Yacoub remodeling in 1 (1%). No in-hospital or 30-day deaths occurred. Despite longer crossclamp and cardiopulmonary bypass times in the valve-sparing group, there were no significant between-group differences in postoperative complications. Thirty-day valve-related complications occurred in 2 (4%) patients undergoing valve replacement and in 3 (3%) undergoing valve-sparing procedures (P = .6). The analysis of early outcomes revealed that valve-sparing techniques were the most common approach to root replacement in patients with Marfan syndrome in these centers. The complexity of valve-sparing root replacement did not translate into any demonstrable adverse early outcomes. Subsequent analysis will compare the 3-year durability of these two surgical approaches.

Multidetector computed tomography sizing of bioprosthetic valves: guidelines for measurement and implications for valve-in-valve therapies

International Nuclear Information System (INIS)

Rajani, R.; Attia, R.; Condemi, F.; Webb, J.; Woodburn, P.; Hodson, D.; Nair, A.; Preston, R.; Razavi, R.; Bapat, V.N.

2016-01-01

Aim: To describe a technique for bioprosthetic multidetector computed tomography (MDCT) sizing and to compare MDCT-derived values against manufacturer-provided sizing. Materials and methods: Fourteen bioprosthetic stented valves commonly used in the aortic valve position were evaluated using a Philips 256 MDCT system. All valves were scanned using a dedicated cardiac CT protocol with a four-channel electrocardiography (ECG) simulator. Measurements were made of major and minor axes and the area and perimeter of the internal stent using varying reconstruction kernels and window settings. Measurements derived from MDCT (MDCT ID) were compared against the stent internal diameter (Stent ID) as provided by the valve manufacturer and the True ID (Stent ID + insertion of leaflets). All data were collected and analysed using SPSS for Mac (version 21). Results: The mean difference between the MDCT ID and Stent ID was 0.6±1.9 mm (r=0.649, p=0.012) and between MDCT ID and True ID 2.1±2 mm (r=0.71, p=0.005). There was no difference in the major (p=0.90), minor (p=0.87), area (p=0.92), or perimeter (p=0.92) measurements when sharp, standard, and detailed stent kernels were used. Similarly, the measurements remained consistent across differing windowing levels. Conclusion: Bioprosthetic stented valves may be reliably sized using MDCT in patients requiring valve-in-valve (VIV) interventions where the valve type and size are unknown. In these cases, clinicians should be aware that MDCT has a tendency to overestimate the True ID size. - Highlights: • Cardiac CT is likely to be ideally suited for bioprosthetic aortic valve sizing for valve in valve procedures. • We compared MDCT sizing for 14 varying bioprosthetic aortic valves across varying window settings and reconstruction kernels. • We provide “normal” MDCT sizing for varying valves and show their relationship to surgical sizing. • Bioprosthetic valves may be reliably sized by MDCT but require adjustment owing to

Swing check valve

International Nuclear Information System (INIS)

Eminger, H.E.

1977-01-01

A swing check valve which includes a valve body having an inlet and outlet is described. A recess in the valve body designed to hold a seal ring and a check valve disc swingable between open and closed positions. The disc is supported by a high strength wire secured at one end in a support spacer pinned through bearing blocks fixed to the valve body and at its other end in a groove formed on the outer peripheral surface of the disc. The parts are designed and chosen such to provide a lightweight valve disc which is held open by minimum velocity of fluid flowing through the valve which thus reduces oscillations and accompanying wear of bearings supporting the valve operating parts. (Auth.)

Correctness of multi-detector-row computed tomography for diagnosing mechanical prosthetic heart valve disorders using operative findings as a gold standard

Energy Technology Data Exchange (ETDEWEB)

Tsai, I.Chen [Taichung Veterans General Hospital, Department of Radiology, Taichung (China); Institute of Clinical Medicine and Faculty of Medicine, National Yang-Ming University, Taipei (China); Lin, Yung-Kai; Chang, Yen; Wang, Chung-Chi; Hsieh, Shih-Rong; Wei, Hao-Ji; Tsai, Hung-Wen [Taichung Veterans General Hospital, Section of Cardiovascular Surgery, Cardiovascular Center, Taichung (China); Fu, Yun-Ching; Jan, Sheng-Ling [Institute of Clinical Medicine and Faculty of Medicine, National Yang-Ming University, Taipei (China); Taichung Veterans General Hospital, Section of Pediatric Cardiology, Department of Pediatrics, Taichung (China); Wang, Kuo-Yang [Taichung Veterans General Hospital, Section of General Cardiology, Cardiovascular Center, Taichung (China); Chung-Shan Medical University, Department of Medicine, Taichung (China); Chen, Min-Chi; Chen, Clayton Chi-Chang [Taichung Veterans General Hospital, Department of Radiology, Taichung (China); Central Taiwan University of Science and Technology, Department of Radiological Technology, Taichung (China)

2009-04-15

The purpose was to compare the findings of multi-detector computed tomography (MDCT) in prosthetic valve disorders using the operative findings as a gold standard. In a 3-year period, we prospectively enrolled 25 patients with 31 prosthetic heart valves. MDCT and transthoracic echocardiography (TTE) were done to evaluate pannus formation, prosthetic valve dysfunction, suture loosening (paravalvular leak) and pseudoaneurysm formation. Patients indicated for surgery received an operation within 1 week. The MDCT findings were compared with the operative findings. One patient with a Bjoerk-Shiley valve could not be evaluated by MDCT due to a severe beam-hardening artifact; thus, the exclusion rate for MDCT was 3.2% (1/31). Prosthetic valve disorders were suspected in 12 patients by either MDCT or TTE. Six patients received an operation that included three redo aortic valve replacements, two redo mitral replacements and one Amplatzer ductal occluder occlusion of a mitral paravalvular leak. The concordance of MDCT for diagnosing and localizing prosthetic valve disorders and the surgical findings was 100%. Except for images impaired by severe beam-hardening artifacts, MDCT provides excellent delineation of prosthetic valve disorders. (orig.)

Mitral valve repair in a rheumatic population: an experience at AFIC/NIHD

International Nuclear Information System (INIS)

Ahmad, M.; Janjuja, A.M.; Iqbal, M.A.

2017-01-01

Objective: To analyze the outcome of mitral valve repair in rheumatic heart disease. Study Design: Retrospective analytical. Place and Duration of Study: Armed forces institute of cardiology/National institute of heart diseases Rawalpindi from Jan 2011 to June 2013. Material and Methods: In this retrospective study of 28 patients (15 females). The mean age was 20.2 +- 11.2 years (range, 11 to 55 years). The cause of mitral regurgitation was rheumatic in all patients, with no congenital myxomatous, infective or ischemic cases. About 68 percent patients were in New York Heart Association (NYHA) functional class III or IV. In all the cases posterior ring annuloplasty was done with flexible C- Shape rings with size ranging from 20 to 26 mm. Repairs included anterior leaflet repair with cusp shortening and resuspension (n=17), posterior leaflet repair with quardranguloplasty and transpositioning (n=6), commissuroplasty (n=2) and mixed anterior posterior leaflet repair (n=3). Results: There was no operative mortality. Follow-up was carried out for 10 months. The trivial mitral regurgitation was found in 3 cases (10.7 percent). Four (14.2 percent) patients required mitral valve replacement due to valve dysfunction. Conclusion: Mitral valve repair in rheumatic patients, with current techniques, can effectively correct functional and hemodynamic abnormalities with satisfactory results. (author)

Valve Disease

Science.gov (United States)

... blood. There are 4 valves in the heart: tricuspid, pulmonary, mitral, and aortic. Two types of problems can disrupt blood flow through the valves: regurgitation or stenosis. Regurgitation is also called insufficiency or incompetence. Regurgitation happens when a valve doesn’ ...

Disc dislodgment in Björk Shiley mitral valve prosthesis: two successfully operated cases.

Science.gov (United States)

Dubernet, J; Irarrázaval, M J; Urzúa, J; Maturana, G; Morán, S; Lema, G; Asenjo, F; Fajuri, A

1986-02-01

Two patients with Björk Shiley mitral valve replacement had migration and embolization of the occluding disc. One patient suffered migration of the disc a few hours after surgery and the other had a strut fracture with disc translocation six years after the initial operation. Clinical signs in both cases were pulmonary edema, cardiogenic shock, and absence of prosthetic sounds. Both patients were reoperated on an emergency basis, recovering after a complicated postoperative course. They are on functional Class I, 8 and 1 years later, respectively, with their dislodged discs still in the abdominal aorta. The only hope for survival in these patients is emergency reoperation, once the prosthetic mitral valve dysfunction is confirmed.

241-AN-A valve pit manifold valves and position indication acceptance test procedure

Energy Technology Data Exchange (ETDEWEB)

VANDYKE, D.W.

1999-08-25

This document describes the method used to test design criteria for gear actuated ball valves installed in 241-AN-A Valve Pit located at 200E Tank Farms. The purpose of this procedure is to demonstrate the following: Equipment is properly installed, labeled, and documented on As-Built drawings; New Manifold Valves in the 241-AN-A Valve Pit are fully operable using the handwheel of the valve operators; New valve position indicators on the valve operators will show correct valve positions; New valve position switches will function properly; and New valve locking devices function properly.

Aortic Valve Stenosis

Science.gov (United States)

... most cases, doctors don't know why a heart valve fails to develop properly, so it isn't something you could have prevented. Calcium buildup on the valve. With age, heart valves may accumulate deposits of calcium (aortic valve ...

Improved corrosion resistance of spin-valve film

International Nuclear Information System (INIS)

Tetsukawa, H.; Hommura, H.; Okabe, A.; Soda, Y.

2007-01-01

We investigated the corrosion behavior and magnetoresistance of spin-valve film in order to improve the corrosion resistance of the spin-valve head for a tape recording system. The conventional spin-valve head (sub./Ta/NiFe/CoFe/Cu/CoFe/PtMn/Ta) with no diamond-like carbon (DLC) protective layer showed poor corrosion resistance. This is because the CoFe for ferromagnetic layer and Cu for spacer in the spin-valve film exhibited poor corrosion resistance. The corrosion resistance of the CoFe film and Cu film improved with the addition of Ni and Au, respectively. The spin-valve film (sub./Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) showed higher pitting potential than the conventional spin-valve film by +0.45 V. This presents a significant improvement over the conventional spin-valve film. We also investigated the effect of the composition of ferromagnetic layer and spacer on the magnetoresistance of the spin-valve film. The magnetoresistance of the spin-valve film by substitution of CoNiFe for CoFe in ferromagnetic layer decreased slightly. The magnetoresistance of the spin-valve film decreased as the addition of Au of the spacer increased. The diffusion at CoNiFe/CuAu interface has not been observed in annealing process. The quantitative relation between corrosion resistance and magnetoresistance of spin-valve film, and its ferromagnetic layer and spacer's compositions have been clarified. The output voltage at 50 Oe of the corrosion-resistant spin-valve head with CoNiFe ferromagnetic layer and CuAu spacer was about 50% of that of the conventional spin-valve head

Improved corrosion resistance of spin-valve film

Energy Technology Data Exchange (ETDEWEB)

Tetsukawa, H. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)]. E-mail: tetsukaw@arc.sony.co.jp; Hommura, H. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan); Okabe, A. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan); Soda, Y. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)

2007-06-15

We investigated the corrosion behavior and magnetoresistance of spin-valve film in order to improve the corrosion resistance of the spin-valve head for a tape recording system. The conventional spin-valve head (sub./Ta/NiFe/CoFe/Cu/CoFe/PtMn/Ta) with no diamond-like carbon (DLC) protective layer showed poor corrosion resistance. This is because the CoFe for ferromagnetic layer and Cu for spacer in the spin-valve film exhibited poor corrosion resistance. The corrosion resistance of the CoFe film and Cu film improved with the addition of Ni and Au, respectively. The spin-valve film (sub./Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) showed higher pitting potential than the conventional spin-valve film by +0.45 V. This presents a significant improvement over the conventional spin-valve film. We also investigated the effect of the composition of ferromagnetic layer and spacer on the magnetoresistance of the spin-valve film. The magnetoresistance of the spin-valve film by substitution of CoNiFe for CoFe in ferromagnetic layer decreased slightly. The magnetoresistance of the spin-valve film decreased as the addition of Au of the spacer increased. The diffusion at CoNiFe/CuAu interface has not been observed in annealing process. The quantitative relation between corrosion resistance and magnetoresistance of spin-valve film, and its ferromagnetic layer and spacer's compositions have been clarified. The output voltage at 50 Oe of the corrosion-resistant spin-valve head with CoNiFe ferromagnetic layer and CuAu spacer was about 50% of that of the conventional spin-valve head.

3-D analysis of reactor loop isolation valves

International Nuclear Information System (INIS)

Dietrich, D.E.

1975-01-01

A full three-dimensional analysis for the design and operational loading conditions was performed on a 29 inch loop isolation valve using the Westinghouse finite element computer code. The 3-D analysis was employed for the valve design in place of utilizing the standard ASME valve design criteria. The valve design employs the design by analysis concept allowed for nuclear class valve. The valve design was evaluated for a set of independent load including pipe reactions and internal pressure. The design pipe reaction loads were based upon maximum fiber pipe stresses at yield for the bending moments, pipe membrane stresses at half yield for the axial load, and pipe maximum shear stress at half yield for the torsional moment. The valve design pressure was the system loop design pressure. The operating and accident condition evaluation included pipe reactions, extended structure forces, system pressure, and system thermal transients. The valve was analyzed for the normal operating, upset, emergency, and faulted loading conditions. These operating and accident conditions used various specified combinations of the supplied generic system pressure, deadweight, thermal, seismic, and LOCA pipe load components. The generic pipe loads are the worst possible postulated loads for any system design. These generic pipe load components were supplied as maximums and minimums so a simplified nozzle analysis was performed to determine the worst case combination for each loading condition. The valve design was shown to meet the design, operating, and accident condition requirements of the ASME code. The design by analysis concept for nuclear class 1 valves gave a significant reduction in required minimum wall thickness, 3.75 inches vs. 5.4 inches. These translate into significant material savings

Valve assembly

International Nuclear Information System (INIS)

Sandling, M.

1981-01-01

An improved valve assembly, used for controlling the flow of radioactive slurry, is described. Radioactive contamination of the air during removal or replacement of the valve is prevented by sucking air from the atmosphere through a portion of the structure above the valve housing. (U.K.)

Mitral Valve Stenosis

Science.gov (United States)

... the left ventricle from flowing backward. A defective heart valve fails to either open or close fully. Risk factors Mitral valve stenosis is less common today than it once was because the most common cause, ... other heart valve problems, mitral valve stenosis can strain your ...

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

Science.gov (United States)

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

2013-01-01

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

Posterior urethral valves: Morphological normalization of posterior urethra after fulguration is a significant factor in prognosis

Directory of Open Access Journals (Sweden)

Menon Prema

2010-01-01

Full Text Available Aim: To assess the changes in urethral morphology 3 months post fulguration of posterior urethral valves (PUVs on micturating cystourethrogram (MCUG and correlate these changes with the overall clinical status of the patient. Materials and Methods: A total of 217 children, managed for PUVs during a period of 6 years in a single surgical unit were prospectively studied. The ratio of the diameters of the prostatic and bulbar urethras (PU/BU was calculated on the pre- and post-fulguration MCUG films. They were categorized into three groups based on the degree of normalization of posterior urethra (post-fulguration PU/BU ratio. Results: Group A: Of the 133 patients, 131 had normal urinary stream and 4 (3% had nocturnal enuresis. Vesicoureteral reflux (VUR, initially seen in 83 units (31% units, regressed completely at a mean duration of 6 months in 41 units (49%. Of the 152 non-VUR, hydroureteronephrosis (HUN units, 11 were poorly functioning kidneys. Persistent slow but unobstructed drainage was seen in 23 units (16% over a period of 1.5-5 years (mean 2.5 years. Group B: All the 11 patients had a normal stream. Four (36.4% had daytime frequency for a mean duration of 1 year and one (9% had nocturnal enuresis for 1 year. Grade IV-V VUR was seen in five patients (three bilateral, which regressed completely by 3 months in five units (62.5%. In the non-VUR, HUN patients, slow (but unobstructed drainage was persistent in two units (14% at 3 years. Group C: Of the 16 patients, only 5 (31.3% were asymptomatic. Six patients (nine units had persistent VUR for 6 months to 3 years. Of the 20 units with HUN, 17 (85% were persistent at 1-4 years (mean 2 years. Eight patients (50% required a second fulguration while 3 (18.7% required urethral dilatation for stricture following which all parameters improved. Conclusions: Adequacy of fulguration should be assessed by a properly performed MCUG. A postop PU/BU ratio >3 SD (1.92 should alert to an incomplete

Aortic valve replacement and the stentless Freedom SOLO valve

NARCIS (Netherlands)

Wollersheim, L.W.L.M.

2016-01-01

Aortic valve stenosis has become the most prevalent valvular heart disease in Europe and North America, and is generally caused by age-related calcification of the aortic valve. For most patients, severe symptomatic aortic stenosis needs effective mechanical relief in the form of valve replacement

Microfluidic sieve valves

Science.gov (United States)

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.

Quantitative assessment of an aortic and pulmonary valve function according to valve fenestration

International Nuclear Information System (INIS)

Mirkhani, S.H.; Golestani, M.G.; Hosini, M.; Kazemian, A.

1999-01-01

There are some reasons for malfunction of aortic and pulmonary valve like fibrosis, calcification, and atheroma. Although, in some papers fenestration were known as a pathologic sign, but it is not generally accepted, while this matter is important in choosing suitable Homograft Heart Valve. In this paper fenestrations and its size, numbers and situation effect was studied. We collected 98 hearts, the donors died because of accident, we excluded valves with atheroma, calcification, fibrosis and unequal cusps, 91 aortic and 93 pulmonary valves were given further consideration. We classified valves according to situation, number and size of fenestration. Each valve was tested with 104 cm of non-nal saline column pressure which is equal to 76 mm Hg. Valve efficacy was detected by fluid flow assay. With study of 184 valves, 95 had no fenestration, 64 had less than 2 fenestration and 25 had more than 2 fenestration. Valve efficacy in condition of less than 2 fenestration was more than others (p <0.01). Malfunction effects of fenestration increased in larger valve and it will be decreased if their situation would be marginal (free margin of cusp). In the comparison of aortic and pulmonary valve we saw that malfunction effect of fenestration in pulmonary valve was more than aortic valve. Our experience in Immam Khomeini Homograft Valve Bank has shown that a great deal of valves is fenestrated. It seems that fenestration must be considered as a quality criterion in homograft valve preparation, especially in pulmonary and large aortic valves; but complementary studies is necessary

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

Science.gov (United States)

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

2017-03-01

Transcatheter aortic valve implantation (TAVI) has become an important treatment in high surgical risk patients with severe aortic stenosis (AS), whose complications need to be managed promptly. The authors report the case of an 86-year-old woman presenting with severe symptomatic AS, rejected for surgery due to advanced age and comorbidities. The patient underwent a first TAVI, with implantation of a Medtronic CoreValve ® , which became dislodged and migrated to the ascending aorta. Due to the previous balloon valvuloplasty, the patient's AS became moderate, and her symptoms improved. After several months, she required another intervention, performed with a St. Jude Portico ® repositionable self-expanding transcatheter aortic valve. There was a good clinical response that was maintained at one-year follow-up. The use of a self-expanding transcatheter bioprosthesis with repositioning features is a solution in cases of valve dislocation to avoid suboptimal positioning of a second implant, especially when the two valves have to be positioned overlapping or partially overlapping each other. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Experimental assessment of valve performance in healthy and diseased right ventricular outflow tracts using magnetic resonance velocimetry

Science.gov (United States)

Schiavone, Nicole; Elkins, Christopher; McElhinney, Doff; Eaton, John K.; Marsden, Alison

2017-11-01

Tetralogy of Fallot (ToF), the most common type of cyanotic congenital heart defect, affects 1 in every 2500 newborns annually and typically requires surgical repair of the right ventricular outflow tract (RVOT) and placement of an artificial pulmonary valve. All artificial valves are subject to dysfunction, but their longevity is highly variable. Clinical observation reveals large variations in RVOT anatomy in ToF patients, which may affect longevity. This work aims to experimentally assess the performance of artificial pulmonary valves in anatomically realistic healthy and diseased RVOT geometries using magnetic resonance velocimetry (MRV). With MRV, we can capture 3D, three-component, phase-averaged velocity fields in 3D printed RVOT geometries. The experiment is designed to ensure physiological flow rate and pressure waveforms, while the RVOT geometries are based on anatomies seen clinically in ToF patients. Two models are used in the current work: an idealized RVOT based on healthy subjects aged eleven to thirteen and a diseased geometry with a dilation of 150% in vessel diameter downstream of the pulmonary valve. We will also present preliminary rigid-wall blood flow simulations in each model, towards the ultimate goal of experimental validation of valve simulations.

Enhancement of pressurizer safety valve operability by seating design improvement

International Nuclear Information System (INIS)

Moisidis, N.T.; Ratiu, M.D.

1994-01-01

Operating conditions specific to Pressurizer Safety Valves (PSVs) have led to numerous problems and have caused industry and NRC concerns regarding the adequacy of spring loaded self-actuated safety valves for Reactor Coolant System (RCS) overpressure protection. Specific concerns are: setpoint drift, spurious actuations and leakage. Based on testing and valve construction analysis of a Crosby model 6M6 PSV, it was established that the primary contributor to the valve problems is a susceptibility to weak seating. To eliminate spring instability, a new spring washer was designed, which guides the spring and precludes its rotation from the reference installed position. Results of tests performed on a prototype PSV equipped with the modified upper spring washer has shown significant improvements in valve operability and a consistent setpoint reproducibility to less than ±1% of the PSV setpoint (testing of baseline, unmodified valve, resulted in a setpoint drift of ±2%). Enhanced valve operability will result in a significant decrease in operating and maintenance costs associated with valve maintenance and testing. In addition, the enhanced setpoint reproducibility will allow the development of a nitrogen to steam correlation for future in-house PSV testing which will result in further reductions in costs associated with valve testing

Rotary pneumatic valve

Science.gov (United States)

Hardee, Harry C.

1991-01-01

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

A symmetric safety valve

International Nuclear Information System (INIS)

Burtraw, Dallas; Palmer, Karen; Kahn, Danny

2010-01-01

How to set policy in the presence of uncertainty has been central in debates over climate policy. Concern about costs has motivated the proposal for a cap-and-trade program for carbon dioxide, with a 'safety valve' that would mitigate against spikes in the cost of emission reductions by introducing additional emission allowances into the market when marginal costs rise above the specified allowance price level. We find two significant problems, both stemming from the asymmetry of an instrument that mitigates only against a price increase. One is that most important examples of price volatility in cap-and-trade programs have occurred not when prices spiked, but instead when allowance prices collapsed. Second, a single-sided safety valve may have unintended consequences for investment. We illustrate that a symmetric safety valve provides environmental and welfare improvements relative to the conventional one-sided approach.

Transcatheter Replacement of Failed Bioprosthetic Valves

DEFF Research Database (Denmark)

Simonato, Matheus; Webb, John; Kornowski, Ran

2016-01-01

postprocedural gradients (mean >= 20 mm Hg). Optimal implantation depths were defined by receiver operating characteristic curve. A total of 292 consecutive patients (age, 78.9 +/- 8.7 years; 60.3% male; 157 CoreValve Evolut and 135 Sapien XT) were evaluated. High implantation was associated with significantly...... lower rates of elevated gradients in comparison with low implantation (CoreValve Evolut, 15% versus 34.2%; P=0.03 and Sapien XT, 18.5% versus 43.5%; P=0.03, respectively). Optimal implantation depths were defined: CoreValve Evolut, 0 to 5 mm; Sapien XT, 0 to 2 mm (0-10% frame height); sensitivities, 91...

Scissor thrust valve actuator

Science.gov (United States)

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

2006-08-29

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

A Systematic Review on Renal and Bladder Dysfunction after Endoscopic Treatment of Infravesical Obstruction in Boys

NARCIS (Netherlands)

Hennus, Pauline M. L.; van der Heijden, Geert J. M. G.; Bosch, J. L. H. Ruud; de Jong, Tom P. V. M.; de Kort, Laetitia M. O.

2012-01-01

Background: Posterior urethral valves (PUV) may cause subtle to severe obstruction of the urethra, resulting in a broad clinical spectrum. PUV are the most common cause of chronic renal disease in boys. Our purpose was to report the incidences of kidney and bladder dysfunction in boys treated with

Porcine Tricuspid Valve Anatomy and Human Compatibility: Relevance for Preclinical Validation of Novel Valve Interventions.

Science.gov (United States)

Waziri, Farhad; Lyager Nielsen, Sten; Michael Hasenkam, John

2016-09-01

Tricuspid regurgitation may be a precursor for heart failure, reduced functional capacity, and poor survival. A human compatible experimental model is required to understand the pathophysiology of the tricuspid valve disease as a basis for validating novel tricuspid valve interventions before clinical use. The study aim was to evaluate and compare the tricuspid valve anatomy of porcine and human hearts. The anatomy of the tricuspid valve and the surrounding structures that affect the valve during a cardiac cycle were examined in detail in 100 fresh and 19 formalin-fixed porcine hearts obtained from Danish Landrace pigs (body weight 80 kg). All valvular dimensions were compared with human data acquired from literature sources. No difference was seen in the tricuspid annulus circumference between porcine and human hearts (13.0 ± 1.2 cm versus 13.5 ± 1.5 cm; p = NS), or in valve area (5.7 ± 1.6 cm2 versus 5.6 ± 1.0 cm2; p = NS). The majority of chordae types exhibited a larger chordal length and thickness in human hearts compared to porcine hearts. In both species, the anterior papillary muscle (PM) was larger than other PMs in the right ventricle, but muscle length varied greatly (range: 5.2-40.3 mm) and was significantly different in pigs and in humans (12.2 ± 3.2 mm versus 19.2 mm; p human hearts.

Heavy gas valves

Energy Technology Data Exchange (ETDEWEB)

Steier, L [Vereinigte Armaturen Gesellschaft m.b.H., Mannheim (Germany, F.R.)

1979-01-01

Heavy gas valves must comply with special requirements. Apart from absolute safety in operation there are stringent requirements for material, sealing and ease of operation even in the most difficult conditions. Ball valves and single plate pipe gate valves lateral sealing rings have a dual, double sided sealing effect according to the GROVE sealing system. Single plate gate valves with lateral protective plates are suitable preferably for highly contaminated media. Soft sealing gate valves made of cast iron are used for low pressure applications.

Cerebral Embolic Protection During Transcatheter Aortic Valve Replacement Significantly Reduces Death and Stroke Compared With Unprotected Procedures.

Science.gov (United States)

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

2017-11-27

The aim of this study was to evaluate the impact of cerebral embolic protection on stroke-free survival in patients undergoing transcatheter aortic valve replacement (TAVR). Imaging data on cerebral embolic protection devices have demonstrated a significant reduction in number and volume of cerebral lesions. A total of 802 consecutive patients were enrolled. The Sentinel cerebral embolic protection device (Claret Medical Inc., Santa Rosa, California) was used in 34.9% (n = 280) of consecutive patients. In 65.1% (n = 522) of patients TAVR was performed in the identical setting except without cerebral embolic protection. Neurological follow-up was done within 7 days post-procedure. The primary endpoint was a composite of all-cause mortality or all-stroke according to Valve Academic Research Consortium-2 criteria within 7 days. Propensity score matching was performed to account for possible confounders. Both filters of the device were successfully positioned in 280 of 305 (91.8%) consecutive patients. With use of cerebral embolic protection rate of disabling and nondisabling stroke was significantly reduced from 4.6% to 1.4% (p = 0.03; odds ratio: 0.29, 95% confidence interval: 0.10 to 0.93) in the propensity-matched population (n = 560). The primary endpoint occurred significantly less frequently, with 2.1% (n = 6 of 280) in the protected group compared with 6.8% (n = 19 of 280) in the control group (p = 0.01; odds ratio: 0.30; 95% confidence interval: 0.12 to 0.77). In multivariable analysis Society of Thoracic Surgeons score for mortality (p = 0.02) and TAVR without protection (p = 0.02) were independent predictors for the primary endpoint. In patients undergoing TAVR use of a cerebral embolic protection device demonstrated a significant higher rate of stroke-free survival compared with unprotected TAVR. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-05-15

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

Bentall operation, total aortic replacement and mitral valve replacement for a young adult with Marfan syndrome: a case of three-staged operation.

Science.gov (United States)

Inui, K; Shimazaki, Y; Watanabe, T; Kuraoka, S; Minowa, T; Miura, M; Oshikiri, S; Toyama, H

1998-08-01

In Marfan syndrome, the most common cardiovascular abnormalities are dilatation of the aorta and aortic valve regurgitation in adult patients. Mitral valve dysfunction is the most common cause of morbidity and mortality in infants and children with Marfan syndrome, and is not frequently operated on in adult Marfan patients who undergo surgery for diseases of the aortic root and total aorta. This report describes a successfully three-staged operation for a 24 year-old man with Marfan syndrome who underwent an emergent Bentall operation and aortic arch replacement, total aortic replacement and mitral valve replacement over 2 years. Mitral valve regurgitation was mild but increased after the second operation. The graft was tightly adhesive and invasive to the sternum. Endoscopic view was helpful to avoid graft damage at resternotomy. The postoperative course was uneventful in each operation. Microscopic examination of the mitral valve leaflets showed abnormal increase of mucopolysaccharides, and disruption and fragmentation of elastic fibers.

Water hammer caused by closure of turbine safety spherical valves

Science.gov (United States)

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

2010-08-01

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

Water hammer caused by closure of turbine safety spherical valves

International Nuclear Information System (INIS)

Karadzic, U; Vukoslavcevic, P; Bergant, A

2010-01-01

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

Water hammer caused by closure of turbine safety spherical valves

Energy Technology Data Exchange (ETDEWEB)

Karadzic, U; Vukoslavcevic, P [Faculty of Mechanical Engineering, University of Montenegro Dzordza Vasingtona nn, Podgorica, 81000 (Montenegro); Bergant, A, E-mail: uros.karadzic@ac.m [LitostrojPower d.o.o., Litostrojska 50, Ljubljana, 1000 (Slovenia)

2010-08-15

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

How to insure quality valve remanufacture

International Nuclear Information System (INIS)

Scott, C.F.

1991-01-01

The importance of quality valve repair for the power generation industry is an obvious need for both the owner as well as the consumer. Whether valves are repaired in-line, on-site, or at a valve remanufacturing facility, the selection of a vendor is vital to meeting not only stringent quality requirements, but also to meet start-up schedules and budgets. In the past, the rule of thumb was that repair of a valve could cost approximately 50% of the cost of a new valve and still represent a significant savings to the end user. For power generation facilities, the fact that many valves are welded in not only makes repair more economical, but even vital to continuing normal operations. For those items not welded in, long lead times and higher prices for these normally exotic alloys make remanufactured valves even more attractive. However, even as these advantages of remanufacturing are obvious, some repair organizations continue to cut corners to meet profit demands. The result is suspect quality in some valves. This can lead to premature failures, possible reduced generating capacity, unscheduled outages, and even catastrophic results. Therefore, the choice of a repair organization must be made with care. As the author has said, repair is an obvious option, but the procurement should definitely involve more than just price comparisons. Evaluation must place the emphasis on quality and reliability. Several aspects should be thoroughly investigated and documented in the selection process. These include: personnel; equipment/facilities; procedures; and credentials

Hemodynamics in the Valsalva sinuses after transcatheter aortic valve implantation (TAVI).

Science.gov (United States)

Ducci, Andrea; Tzamtzis, Spyridon; Mullen, Michael J; Burriesci, Gaetano

2013-09-01

The study aim was to assess, in vitro, the hemodynamic modifications produced by transcatheter valves in the Valsalva sinuses, by mean of phase-resolved particle image velocimetry (PIV) measurements. Flow measurements were performed on a glass mock aortic root that included three polymeric valve leaflets, before and after the implantation of a Medtronic CoreValve device and of an Edwards SAPIEN valve. All experiments were carried out in a hydro-mechanical cardiovascular pulse duplicator system (Vivitro Superpump System SP3891) that reproduced physiologically equivalent pressures and flow rates conforming to the requirements of the standard ISO 5840:2005. The flow dynamics, before and after implantation of the two prosthetic devices, was characterized on the basis of phase-resolved velocity field and viscous shear rate measurements. Direct comparison indicated that both transcatheter valves determined a significant variation of flow during the early stages of valve opening and during valve closure. In general, the presence of the two valve implants significantly reduced the flow activity in the Valsalva sinuses, promoting regions of stagnation at their base. The reduction in flow in the Valsalva sinuses could be associated with the higher incidence of ischemic events reported after transcatheter heart valve implantation.

THE PROGNOSIS IN TRANSCATHETER AORTIC VALVE IMPLANTATION

Directory of Open Access Journals (Sweden)

T. E. Imaev

2016-01-01

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

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

Science.gov (United States)

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

2012-04-17

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

Trabeculectomy versus Ahmed Glaucoma Valve implantation in neovascular glaucoma

Science.gov (United States)

Shen, Christopher C; Salim, Sarwat; Du, Haiming; Netland, Peter A

2011-01-01

Purpose: To compare surgical outcomes in neovascular glaucoma patients who underwent trabeculectomy with mitomycin C versus Ahmed Glaucoma Valve implantation. Patients and methods: This was a retrospective comparative case series. We reviewed 40 eyes of 39 patients with underlying diagnosis of neovascular glaucoma, divided into two groups: Ahmed Glaucoma Valve (N = 20) and trabeculectomy with mitomycin C (N = 20). Surgical success was defined as 6 mm Hg ≤ intraocular pressure ≤21 mm Hg, with or without the use of glaucoma medications, with no further glaucoma surgery, and light perception or better vision. Early postoperative hypotony was defined as intraocular pressure Ahmed Glaucoma Valve group and 25 months (6–77 months) for the trabeculectomy group. Although the mean number of postoperative intraocular pressure-lowering medications was significantly higher in the trabeculectomy group compared with the Ahmed Glaucoma Valve group at 3 and 6 month time points, there was no statistically significant difference at any other time point. There was no statistically significant difference between both groups in postoperative visual acuity and intraocular pressure. Success was 70% and 65% at 1 year and 60% and 55% at 2 years after Ahmed Glaucoma Valve and trabeculectomy, respectively. Kaplan–Meier survival curve analysis showed no significant difference in success between the two groups (P = 0.815). Hyphema was the most common complication in both groups. Conclusion: We found similar results after trabeculectomy with mitomycin C and Ahmed Glaucoma Valve implantation in eyes with neovascular glaucoma. PMID:21468334

Magnetically operated check valve

Science.gov (United States)

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

1994-06-01

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

Enhancement of pressurizer safety valve operability by seating design improvement

International Nuclear Information System (INIS)

Moisidis, N.T.; Ratiu, M.D.

1995-01-01

Operating conditions specific to pressurizer safety valves (PSVs) have led to numerous problems and have caused industry and NRC concerns regarding the adequacy of spring-loaded self-actuated safety valves for reactor coolant system (RCS) overpressure protection. Specific concerns are: setpoint drift, spurious actuations, and pressure protection. Specific concerns are: setpoint drift, spurious actuations, and leakage. Based on testing and valve construction analysis of a Crosby model 6M6 PSV (Moisidis and Ratiu, 1992), it was established that the primary contributor to the valve problems is a susceptibility to weak seating. To eliminate spring instability, a new spring washer was designed, which guides the spring and precludes its rotation from the reference installed position. Results of tests performed on a prototype PSV equipped with the modified upper spring washer has shown significant improvements in valve operability and a consistent setpoint reproducibility to less than ±1% of the PSV setpoint (testing of baseline, unmodified valve, resulted in a setpoint drift of ± 2%). Enhanced valve operability will result in a significant decrease in operating and maintenance costs associated with valve maintenance and testing. In addition, the enhanced setpoint reproducibility will allow the development of a nitrogen to steam correlation for future in-house PSV testing which will result in further reductions in costs associated with valve testing

A remote control valve

International Nuclear Information System (INIS)

Cachard, Maurice de; Dumont, Maurice.

1976-01-01

This invention concerns a remote control valve for shutting off or distributing a fluid flowing at a high rate and low pressure. Among the different valves at present in use, electric valves are the most recommended for remote control but their reliability is uncertain and they soon become costly when large diameter valves are used. The valve described in this invention does away with this drawback owing to its simplicity and the small number of moving parts, this makes it particularly reliable. It mainly includes: a tubular body fitted with at least one side opening; at least one valve wedge for this opening, coaxial with the body, and mobile; a mobile piston integral with this wedge. Several valves to the specifications of this invention can be fitted in series (a shut-off valve can be used in conjunction with one or more distribution valves). The fitting and maintenance of the valve is very simple owing to its design. It can be fabricated in any material such as metals, alloys, plastics and concrete. The structure of the valve prevents the flowing fluid from coming into contact with the outside environment, thereby making it particularly suitable in the handling of dangerous or corrosive fluids. Finally, the opening and shutting of the valve occurs slowly, thereby doing away with the water hammer effect so frequent in large bore pipes [fr

Incidence and progression of mild aortic regurgitation after Tirone David reimplantation valve-sparing aortic root replacement.

Science.gov (United States)

Stephens, Elizabeth H; Liang, David H; Kvitting, John-Peder Escobar; Kari, Fabian A; Fischbein, Michael P; Mitchell, R Scott; Miller, D Craig

2014-01-01

The study objective was to determine whether recurrent or residual mild aortic regurgitation, which occurs after valve-sparing aortic root replacement, progresses over time. Between 2003 and 2008, 154 patients underwent Tirone David-V valve-sparing aortic root replacement; 96 patients (62%) had both 1-year (median, 12 ± 4 months) and mid-term (62 ± 22 months) transthoracic echocardiograms available for analysis. Age of patients averaged 38 ± 13 years, 71% were male, 31% had a bicuspid aortic valve, 41% had Marfan syndrome, and 51% underwent aortic valve repair, predominantly cusp free margin shortening. Forty-one patients (43%) had mild aortic regurgitation on 1-year echocardiogram. In 85% of patients (n = 35), mild aortic regurgitation remained stable on the most recent echocardiogram (median, 57 ± 20 months); progression to moderate aortic regurgitation occurred in 5 patients (12%) at a median of 28 ± 18 months and remained stable thereafter; severe aortic regurgitation developed in 1 patient, eventually requiring reoperation. Five patients (5%) had moderate aortic regurgitation at 1 year, which did not progress subsequently. Two patients (2%) had more than moderate aortic regurgitation at 1 year, and both ultimately required reoperation. Although mild aortic regurgitation occurs frequently after valve-sparing aortic root replacement, it is unlikely to progress over the next 5 years and should not be interpreted as failure of the valve-preservation concept. Further, we suggest that mild aortic regurgitation should not be considered nonstructural valve dysfunction, as the 2008 valve reporting guidelines would indicate. We need 10- to 15-year follow-up to learn the long-term clinical consequences of mild aortic regurgitation early after valve-sparing aortic root replacement. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in "real-world" patients with aortic stenosis and intermediate- to high-risk profile.

Science.gov (United States)

Muneretto, Claudio; Alfieri, Ottavio; Cesana, Bruno Mario; Bisleri, Gianluigi; De Bonis, Michele; Di Bartolomeo, Roberto; Savini, Carlo; Folesani, Gianluca; Di Bacco, Lorenzo; Rambaldini, Manfredo; Maureira, Juan Pablo; Laborde, Francois; Tespili, Maurizio; Repossini, Alberto; Folliguet, Thierry

2015-12-01

We sought to investigate the clinical outcomes of patients with isolated severe aortic stenosis and an intermediate- to high-risk profile treated by means of conventional surgery (surgical aortic valve replacement), sutureless valve implantation, or transcatheter aortic valve replacement in a multicenter evaluation. Among 991 consecutive patients with isolated severe aortic stenosis and an intermediate- to high-risk profile (Society of Thoracic Surgeons score >4 and logistic European System for Cardiac Operative Risk Evaluation I >10), a propensity score analysis was performed on the basis of the therapeutic strategy: surgical aortic valve replacement (n = 204), sutureless valve implantation (n = 204), and transcatheter aortic valve replacement (n = 204). Primary end points were 30-day mortality and overall survival at 24-month follow-up; the secondary end point was survival free from a composite end point of major adverse cardiac events (defined as cardiac-related mortality, myocardial infarction, cerebrovascular accidents, and major hemorrhagic events) and periprosthetic regurgitation greater than 2. Thirty-day mortality was significantly higher in the transcatheter aortic valve replacement group (surgical aortic valve replacement = 3.4% vs sutureless = 5.8% vs transcatheter aortic valve replacement = 9.8%; P = .005). The incidence of postprocedural was 3.9% in asurgical aortic valve replacement vs 9.8% in sutureless vs 14.7% in transcatheter aortic valve replacement (Prisk factor for overall mortality hazard ratio (hazard ratio, 2.5; confidence interval, 1.1-4.2; P = .018). The use of transcatheter aortic valve replacement in patients with an intermediate- to high-risk profile was associated with a significantly higher incidence of perioperative complications and decreased survival at short- and mid-term when compared with conventional surgery and sutureless valve implantation. Copyright © 2015 The American Association for Thoracic Surgery. Published by

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

NARCIS (Netherlands)

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

2016-01-01

Mitral valve leaflet aneurysm is a rare and potentially devastating complication of aortic valve endocarditis. We report the case of a 48-year-old man who had endocarditis of the native aortic valve and a concomitant aneurysm of the anterior mitral valve leaflet. Severe mitral regurgitation occurred

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

Science.gov (United States)

Bradley, Scott M

2013-10-01

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

Infective endocarditis following transcatheter aortic valve replacement-

DEFF Research Database (Denmark)

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

2013-01-01

Transcatheter aortic valve replacement (TAVR) can improve the symptoms and prognosis of patients with severe aortic stenosis who, due to a high expected operative risk, would not have otherwise been treated surgically. If these patients develop prosthetic valve endocarditis, their presentations may...... be atypical causing a delay in the diagnosis and treatment. The management is also complicated by their comorbidities, and surgical treatment may not be feasible leading to a significant morbidity and mortality. We describe a case of an 85-year-old man with TAVI prosthetic valve endocarditis successfully...

Comprehensive 4-stage categorization of bicuspid aortic valve leaflet morphology by cardiac MRI in 386 patients.

Science.gov (United States)

Murphy, I G; Collins, J; Powell, A; Markl, M; McCarthy, P; Malaisrie, S C; Carr, J C; Barker, A J

2017-08-01

Bicuspid aortic valve (BAV) disease is heterogeneous and related to valve dysfunction and aortopathy. Appropriate follow up and surveillance of patients with BAV may depend on correct phenotypic categorization. There are multiple classification schemes, however a need exists to comprehensively capture commissure fusion, leaflet asymmetry, and valve orifice orientation. Our aim was to develop a BAV classification scheme for use at MRI to ascertain the frequency of different phenotypes and the consistency of BAV classification. The BAV classification scheme builds on the Sievers surgical BAV classification, adding valve orifice orientation, partial leaflet fusion and leaflet asymmetry. A single observer successfully applied this classification to 386 of 398 Cardiac MRI studies. Repeatability of categorization was ascertained with intraobserver and interobserver kappa scores. Sensitivity and specificity of MRI findings was determined from operative reports, where available. Fusion of the right and left leaflets accounted for over half of all cases. Partial leaflet fusion was seen in 46% of patients. Good interobserver agreement was seen for orientation of the valve opening (κ = 0.90), type (κ = 0.72) and presence of partial fusion (κ = 0.83, p < 0.0001). Retrospective review of operative notes showed sensitivity and specificity for orientation (90, 93%) and for Sievers type (73, 87%). The proposed BAV classification schema was assessed by MRI for its reliability to classify valve morphology in addition to illustrating the wide heterogeneity of leaflet size, orifice orientation, and commissural fusion. The classification may be helpful in further understanding the relationship between valve morphology, flow derangement and aortopathy.

[Nitrid oxide, levosimendan and sildenafile in a patient with right ventricle dysfunction and severe pulmonary hypertension after cardiac surgery].

Science.gov (United States)

Aleixandre, L; Cortell, J; Vicente, R; Herrera, P; Loro, J M; Valera, F

2014-11-01

Pulmonary hypertension (PHT) and the resulting right ventricle dysfunction are important risk factors in patients who undergo cardiac surgery. The treatment of PHT and right ventricle dysfunction should be focused on maintaining the correct right ventricle after load, improving right ventricle function and reducing the right ventricle pre-load and therefore reducing pulmonary vascular resistance by means of vasodilators. A combined therapy of vasodilators and medicines which have different mechanisms of action, is becoming an option for the treatment of PHT. We present a 65 year old woman that suffered from mitral regurgitation, aortic valve disease, tricuspid and ascending aortic dilation with 115mmHg of pulmonary artery pressure (by ultrasound evaluation). The patient was operated on of mitral, aortic valve and tricuspid plastia and proximal aortic artery plastia as well. Previosly to surgery the patient suffered right ventricle dysfunction and PHT and was treated with nitric oxide, intravenous sildenafil and levosimendan. Subsequent evolution was satisfactory, PHT being controlled, without arterial hypotension nor respiratory alterations. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Methodology for Check Valve Selection to Maintain the Integrity of Pipeline against the Check Valve Slam for the KIJANG Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Kim, Dayong; Yoon, Hyungi; Seo, Kyoungwoo; Kim, Seonhoon [KAERI, Daejeon (Korea, Republic of)

2016-05-15

The check valve slam results in a water hammer and unexpected system pressure rise in the pipeline. Sometimes, the pressure rise by check valve slam in the pipeline exceeds the design pressure and then it causes the rupture of pipeline. Therefore, check valve slam significantly influences on the integrity of pipe. Especially, this it is most likely to occur by check valve installed in the discharge of pump when one pump trips among the two or more running in parallel pump system. This study focuses on the check valve selection to maintain the integrity of PCS pipeline against the check valve slam. If design head for KJRR PCS pipeline is higher than the sum of static head and 11 m, any type check valves can be installed at the discharge of pump. However, if design head for KJRR PCS pipeline is lower than the sum of static head and 11 m, installation of swing and ball check on the discharge of pump must be avoid to prevent the rupture of PCS pipeline.

Methodology for Check Valve Selection to Maintain the Integrity of Pipeline against the Check Valve Slam for the KIJANG Research Reactor

International Nuclear Information System (INIS)

Kim, Dayong; Yoon, Hyungi; Seo, Kyoungwoo; Kim, Seonhoon

2016-01-01

The check valve slam results in a water hammer and unexpected system pressure rise in the pipeline. Sometimes, the pressure rise by check valve slam in the pipeline exceeds the design pressure and then it causes the rupture of pipeline. Therefore, check valve slam significantly influences on the integrity of pipe. Especially, this it is most likely to occur by check valve installed in the discharge of pump when one pump trips among the two or more running in parallel pump system. This study focuses on the check valve selection to maintain the integrity of PCS pipeline against the check valve slam. If design head for KJRR PCS pipeline is higher than the sum of static head and 11 m, any type check valves can be installed at the discharge of pump. However, if design head for KJRR PCS pipeline is lower than the sum of static head and 11 m, installation of swing and ball check on the discharge of pump must be avoid to prevent the rupture of PCS pipeline

Features of mitral valve prolapse in young patients

Directory of Open Access Journals (Sweden)

M. A. Kuznetsova

2015-06-01

Full Text Available Due to the significant increase of complications in young patients with mitral valve prolapse detection of this disease is important. Aim. With the aim of studying the features of mitral valve prolapse 135 persons with mitral valve prolapse at the age of 18–25 years were examined. Methods and results. The features of mitral valve prolapsed were studied with echocardiography, electrocardiography, cardiointervalography. It was established that mitral valve prolapse (MVP in young age had different clinical picture. Patients with MVP 1 degree mainly had autonomic instability, and with 2 degree - mostly signs of connective tissue dysplasia. Conclusion. The presence of MVP is associated with abnormalities of the rhythm and conductivity: 1 degree - sinus tachycardia; the 2nd - sinus arrhythmia, signs of left ventricular hypertrophy and impaired repolarization of the myocardium.

Design and performance characteristic analysis of servo valve-type water hydraulic poppet valve

International Nuclear Information System (INIS)

Park, Sung Hwan

2009-01-01

For water hydraulic system control, the flow or pressure control using high-speed solenoid valve controlled by PWM control method could be a good solution for prevention of internal leakage. However, since the PWM control of on-off valves cause extensive flow and pressure fluctuation, it is difficult to control the water hydraulic actuators precisely. In this study, the servo valve-type water hydraulic valve using proportional poppet as the main valve is designed and the performance characteristics of the servo valve-type water hydraulic valve are analyzed. Furthermore, it is demonstrated through experiments that a decline in control chamber pressure that follows the change of pilot flow is caused by the occurrence of cavitation around the proportional poppet, and that fundamental characteristics of the developed valve remain unaffected by the occurrence of cavitation

Single leg separation prevalence among explanted Björk-Shiley prosthetic heart valves.

Science.gov (United States)

Blot, William J; Signorello, Lisa B; Cohen, Sarah S; Ibrahim, Michel A

2007-11-01

Björk-Shiley convexo-concave (BSCC) prosthetic heart valves are believed to have been implanted in over 86,000 patients worldwide. Limited data are available on the prevalence of single leg separations (SLS) of the valves' outlet struts, a potential precursor to complete valve fracture. Data maintained by the manufacturer, including results of examinations for SLS in explanted valves, were merged with available information on the characteristics of the valve. The prevalence of SLS in the examined valves was calculated according to valve angle, size, position, and study. Among 343 examined valves, the overall prevalence of SLS was 8.2%, but this varied significantly by valve size, being three-fold higher among 29+ mm valves than among smaller valves, with statistically non-significantly higher prevalences among mitral than aortic, and among 70 degrees than 60 degrees valves. By applying the size, position and angle-specific SLS prevalences to the worldwide valve distribution, it is estimated that SLS may be present in 6.8% (95% confidence limits 4.1-9.4%) of all BSCC valves. These findings suggest that SLS may affect between 820 and 1,880 of the almost 20,000 BSCC valves among surviving patients worldwide. Such estimates help frame the context for potential patient screenings, should imaging and acoustic techniques to detect SLS become available.

Reducing dysfunctional beliefs about sleep does not significantly improve insomnia in cognitive behavioral therapy.

Science.gov (United States)

Okajima, Isa; Nakajima, Shun; Ochi, Moeko; Inoue, Yuichi

2014-01-01

The present study examined to examine whether improvement of insomnia is mediated by a reduction in sleep-related dysfunctional beliefs through cognitive behavioral therapy for insomnia. In total, 64 patients with chronic insomnia received cognitive behavioral therapy for insomnia consisting of 6 biweekly individual treatment sessions of 50 minutes in length. Participants were asked to complete the Athens Insomnia Scale and the Dysfunctional Beliefs and Attitudes about Sleep scale both at the baseline and at the end of treatment. The results showed that although cognitive behavioral therapy for insomnia greatly reduced individuals' scores on both scales, the decrease in dysfunctional beliefs and attitudes about sleep with treatment did not seem to mediate improvement in insomnia. The findings suggest that sleep-related dysfunctional beliefs endorsed by patients with chronic insomnia may be attenuated by cognitive behavioral therapy for insomnia, but changes in such beliefs are not likely to play a crucial role in reducing the severity of insomnia.

Which valve is which?

Directory of Open Access Journals (Sweden)

Pravin Saxena

2015-01-01

Full Text Available A 25-year-old man presented with a history of breathlessness for the past 2 years. He had a history of operation for Tetralogy of Fallot at the age of 5 years and history suggestive of Rheumatic fever at the age of 7 years. On echocardiographic examination, all his heart valves were severely regurgitating. Morphologically, all the valves were irreparable. The ejection fraction was 35%. He underwent quadruple valve replacement. The aortic and mitral valves were replaced by metallic valve and the tricuspid and pulmonary by tissue valve.

David valve-sparing aortic root replacement: equivalent mid-term outcome for different valve types with or without connective tissue disorder.

Science.gov (United States)

Kvitting, John-Peder Escobar; Kari, Fabian A; Fischbein, Michael P; Liang, David H; Beraud, Anne-Sophie; Stephens, Elizabeth H; Mitchell, R Scott; Miller, D Craig

2013-01-01

Although implicitly accepted by many that the durability of valve-sparing aortic root replacement in patients with bicuspid aortic valve disease and connective tissue disorders will be inferior, this hypothesis has not been rigorously investigated. From 1993 to 2009, 233 patients (27% bicuspid aortic valve, 40% Marfan syndrome) underwent Tirone David valve-sparing aortic root replacement. Follow-up averaged 4.7 ± 3.3 years (1102 patient-years). Freedom from adverse outcomes was determined using log-rank calculations. Survival at 5 and 10 years was 98.7% ± 0.7% and 93.5% ± 5.1%, respectively. Freedom from reoperation (all causes) on the aortic root was 92.2% ± 3.6% at 10 years; 3 reoperations were aortic valve replacement owing to structural valve deterioration. Freedom from structural valve deterioration at 10 years was 96.1% ± 2.1%. No significant differences were found in survival (P = .805, P = .793, respectively), reoperation (P = .179, P = .973, respectively), structural valve deterioration (P = .639, P = .982, respectively), or any other functional or clinical endpoints when patients were stratified by valve type (tricuspid aortic valve vs bicuspid aortic valve) or associated connective tissue disorder. At the latest echocardiographic follow-up (95% complete), 202 patients (94.8%) had none or trace aortic regurgitation, 10 (4.7%) mild, 0 had moderate to severe, and 1 (0.5%) had severe aortic regurgitation. Freedom from greater than 2+ aortic regurgitation at 10 years was 95.3% ± 2.5%. Six patients sustained acute type B aortic dissection (freedom at 10 years, 90.4% ± 5.0%). Tirone David reimplantation valve-sparing aortic root replacement in carefully selected young patients was associated with excellent clinical and echocardiographic outcome in patients with either a tricuspid aortic valve or bicuspid aortic valve. No demonstrable adverse influence was found for Marfan syndrome or connective tissue disorder on durability, clinical outcome

Mitral Valve Prolapse

Science.gov (United States)

Mitral valve prolapse (MVP) occurs when one of your heart's valves doesn't work properly. The flaps of the valve are "floppy" and ... to run in families. Most of the time, MVP doesn't cause any problems. Rarely, blood can ...

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

DEFF Research Database (Denmark)

Aagaard, Jan; Geha, Alexander S.

2007-01-01

BACKGROUND AND AIM OF THE STUDY: The CarboMedics Top Hat supra-annular aortic valve allows a one-size (and often two-size) increase over the standard intra-annular valve. This advantage should minimize the risk of patient-prosthesis mismatch, where the effective prosthetic valve orifice area....... This study evaluates the authors' clinical experience with Top Hat supra-annular aortic valve size selection, and the technical aspects of implantation. METHODS: Between January 1999 and October 2005, a total of 251 consecutive patients underwent 252 aortic valve replacements with Top Hat supra...... required unplanned coronary bypass, and 30-day mortality was 2.0% (5/251), indicating a good safety profile for the valves implanted in this series. CONCLUSION: The general distribution of implant sizes in the US indicates that cardiac surgeons may be under-sizing the Top Hat supra-annular aortic valve...

Thrombocytopenia following implantation of the stentless biological sorin freedom SOLO valve.

Science.gov (United States)

Gersak, Borut; Gartner, Urska; Antonic, Miha

2011-07-01

Stentless biological valves have proven advantages in hemodynamic performance and left ventricular function compared to stented biological valves. Following a marked postoperative fall in the platelet count of patients after implantation of the Freedom SOLO valve, the study aim was to confirm clinical observations that this effect was more severe in patients receiving Freedom SOLO valves than in those receiving St. Jude Medical (SJM) mechanical aortic valves. Preoperative and postoperative platelet counts were compared in two groups of patients who underwent aortic valve replacement (AVR) without any concomitant procedures between January and December 2007. Patients received either a Freedom SOLO valve (n = 28) or a SJM mechanical valve (n = 41). Mean values of platelet counts were compared using three multiple linear regression models. Platelet counts were significantly lower in the Freedom SOLO group than in the SJM group from the first postoperative day (POD 1) up to POD 6 (p SOLO group the platelet count fell below 30x10(9)/l, while the lowest level in the SJM group was 75x10(9)/l. Based on multiple linear regression models, the type of valve implanted had a statistically significant influence on postoperative platelet counts on POD 1, POD 3, and POD 5 (p SOLO group.

Mechanism study of freeze-valve for molten salt reactor (MSR)

International Nuclear Information System (INIS)

Qinhua, Zhang

2014-01-01

Molten salt reactor (MSR) is one of the fourth generation nuclear reactor, ordinary nuclear grade valve is unsuitable for MSR due to its special coolant and extraordinary working temperature. Freeze-valve is proposed as the most appropriate valve for MSR, but the technology issue about freeze-valve has not been report in recent decades. Its significance to test the comprehensive property of freeze-valve for the application in MSR. A high temperature molten salt test loop was built which the physics property of salt is similar to the coolant of MSR. The results indicate that freeze-valve has a good performance use in the molten salt circumstances of high temperature (max 700 deg. C) and strong corrosion (authors)

Effect of the mitral valve on diastolic flow patterns

International Nuclear Information System (INIS)

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

2014-01-01

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

Fate of remnant sinuses of Valsalva in patients with bicuspid and trileaflet valves undergoing aortic valve, ascending aorta, and aortic arch replacement.

Science.gov (United States)

Milewski, Rita Karianna; Habertheuer, Andreas; Bavaria, Joseph E; Siki, Mary; Szeto, Wilson Y; Krause, Eric; Korutla, Varun; Desai, Nimesh D; Vallabhajosyula, Prashanth

2017-08-01

In patients presenting with aortic valvulopathy with concomitant ascending aortic aneurysm, surgical management of the sinus of Valsalva segment remains undefined, especially for moderately dilated aortic roots. In patients with this pathology undergoing aortic valve replacement with supracoronary ascending aorta replacement, we assessed the fate of the remnant preserved sinus of Valsalva segment stratified by aortic valve morphology and pathology. From 2002 to 2015, 428 patients underwent elective aortic valve replacement with supracoronary ascending aorta replacement. Patients were stratified on the basis of valvular morphology (bicuspid aortic valve [n = 254] and tricuspid aortic valve [n = 174]), valvular pathology (bicuspid aortic valve with aortic stenosis [n = 178], bicuspid aortic valve with aortic insufficiency [n = 76], tricuspid aortic valve with aortic stenosis [n = 61], tricuspid aortic valve with aortic insufficiency [n = 113]), and preoperative sinus of Valsalva dimensions (45 mm). Kaplan-Meier analysis revealed no significant difference in freedom from reoperation in tricuspid aortic valve versus bicuspid aortic valve (P = .576). Multivariable Cox regression model performed with sinus of Valsalva dimensions at baseline and follow-up as time-varying covariates did not adversely affect survival. A repeated-measure, mixed-effects model constructed to assess longitudinal sinus of Valsalva trends revealed that the retained sinus of Valsalva dimensions remain stable over long-term follow-up (discharge to ≥10 years), irrespective of valvular morphology/pathology (bicuspid aortic valve with aortic insufficiency, tricuspid aortic valve with aortic insufficiency, tricuspid aortic valve with aortic stenosis) and preoperative sinus of Valsalva groups (45 mm). In patients with nonaneurysmal sinuses of Valsalva undergoing aortic valve replacement with supracoronary ascending aorta replacement, the sinus segment can be preserved irrespective of

AREVA's innovative solutions for valve diagnostics and in-situ valve repair

International Nuclear Information System (INIS)

Damies, H.; Breitenberger, U.; Munoz, L.; Kostroun, F.

2012-01-01

Optimized maintenance strategies are a key aspect for safe and undisturbed plant operation. Innovative valve service solutions can support that in an efficient way. The ADAM®/SIPLUG® valve monitoring system allows full online monitoring of valves and actuators with automatic evaluation and assessment. Especially for safety-related and operation-related valves this provides valuable information on components condition to ensure proper function and contribute to optimization of maintenance strategies as well as effective maintenance performance. More than 25 years of experience in various plants worldwide show that application of ADAM®/SIPLUG® valve diagnostics solution leads to increased plant safety and availability. With the innovative AVARIS technology an in-situ valve repair is possible. It has the unique ability to conduct several steps in-situ, to maintain the sealing seat of gate or check valves. By applying AVARIS, the valve is restored in its original state, the system remains unchanged. Thus, all original documents remain valid and applicable. In comparison to previous procedures like cutting valves out of the pipeline and repairing hard facings or damaged seal seats in a separate workshop or alternatively replacement by a new valve body the new AVARIS technology avoids costs, risk and effort. (author)

Early and mid-term results of autograft rescue by Ross reversal: A one-valve disease need not become a two-valve disease.

Science.gov (United States)

Hussain, Syed T; Majdalany, David S; Dunn, Aaron; Stewart, Robert D; Najm, Hani K; Svensson, Lars G; Houghtaling, Penny L; Blackstone, Eugene H; Pettersson, Gösta B

2018-02-01

Risk of reoperation and loss of a second native valve are major drawbacks of the Ross operation. Rather than discarding the failed autograft, it can be placed back into the native pulmonary position by "Ross reversal." We review our early and mid-term results with this operation. From 2006 to 2017, 39 patients underwent reoperation for autograft dysfunction. The autograft was successfully rescued in 35 patients: by Ross reversal in 30, David procedure in 4, and autograft repair in 1. Medical records were reviewed for patient characteristics (mean age was 46 ± 13 years, range 18-67 years, and 23 were male), previous operations, indications for reoperation, hospital outcomes, and echocardiographic findings for the 30 patients undergoing successful Ross reversal. Follow-up was 4.1 ± 3.5 years (range 7 months-11 years). Median interval between the original Ross procedure and Ross reversal was 12 years (range 5-19 years). Eight patients also had absolute indications for replacement of the pulmonary allograft. There was no operative mortality. One patient required reoperation for bleeding. Another had an abdominal aorta injury from use of an endoballoon clamp. There was no other major postoperative morbidity, and median postoperative hospital stay was 7.2 days (range 4-41 days). No patient required reoperation during follow-up. Twenty-four patients had acceptable pulmonary valve function, and 6 had clinically well-tolerated moderate or severe pulmonary regurgitation. Ross reversal can be performed with low morbidity and acceptable pulmonary valve function, reducing patient risk of losing 2 native valves when the autograft fails in the aortic position. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Fabrication of Microfluidic Valves Using a Hydrogel Molding Method.

Science.gov (United States)

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.

Late complications in patients with Björk-Shiley and St. Jude Medical heart valve replacement.

Science.gov (United States)

Horstkotte, D; Körfer, R; Seipel, L; Bircks, W; Loogen, F

1983-09-01

Valve-related complications after Björk-Shiley mitral valve implantation (n = 475), aortic valve implantation (n = 424), or mitral-aortic valve implantation (n = 119) were compared with those after St. Jude Medical mitral valve replacement (n = 173), aortic valve replacement (n = 152), or mitral-aortic valve replacement (n = 69). All patients were placed on anticoagulant therapy with phenprocoumon early after operation. All patients had a comparable follow-up time of approximately 23 months, which showed that cumulative thromboembolic rates were significantly higher after St. Jude valve implantation than after Björk-Shiley valve implantation. Reoperations were necessary because of valve thrombosis (0.46%), perivalvular leakage (2.2%), or prosthetic valve endocarditis with perivalvular regurgitation (0.46%). One Björk-Shiley mitral valve prosthesis had to be replaced because of fracture of the outlet strut. Without significant intergroup differences, hemorrhage due to anticoagulant treatment was the most frequent complication. Thromboembolic complications were significantly more frequent after Björk-Shiley mitral, aortic, and double valve replacements than after St. Jude valve implantation. This may lead to consideration of changes in the prophylaxis of thrombus formations in the St. Jude valve, especially in aortic valve replacements, in patients with sinus rhythm.

Check valve diagnostics utilizing acoustic and magnetic technologies

International Nuclear Information System (INIS)

Agostinelli, A.

1991-01-01

The potential hazards associated with check valve failures make it necessary to detect check valve problems before they cause significant damage. In the nuclear industry, check valve failures are known to have resulted in damaging water hammer conditions, overpressurization of low pressure systems, steam binding of auxiliary feedwater pumps, and other serious component damage in power plant environments. Similar problems exist in fossil power and various process industries, but the resources dedicated to valve maintenance issues are greatly reduced. However, the trend toward plant life extension, predictive maintenance, and maximum operating efficiency will raise the general awareness of check valve maintenance in commercial (non-nuclear) applications. Although this paper includes specific references to the nuclear industry, the check valve problem conditions and diagnostic techniques apply across all power and process plant environments. The ability to accurately diagnose check valve conditions using non-intrusive, predictive maintenance testing methods allows for a more cost-efficient, productive maintenance program. One particular diagnostic system, called Quickcheck trademark, assists utilities in addressing these concerns. This article presents actual field test data and analysis that demonstrate the power of check valve diagnostics. Prior to presenting the field data, a brief overview of the system is overviewed

Heart Valve Diseases

Science.gov (United States)

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

Prosthetic valve endocarditis after transcatheter aortic valve implantation

DEFF Research Database (Denmark)

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

2015-01-01

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is an advancing mode of treatment for inoperable or high-risk patients with aortic stenosis. Prosthetic valve endocarditis (PVE) after TAVI is a serious complication, but only limited data exist on its incidence, outcome, and procedural......%) were treated conservatively and 1 with surgery. Four patients (22%) died from endocarditis or complications to treatment, 2 of those (11%) during initial hospitalization for PVE. An increased risk of TAVI-PVE was seen in patients with low implanted valve position (hazard ratio, 2.8 [1.1-7.2]), moderate...

Modeling of Dynamic Fluid Forces in Fast Switching Valves

DEFF Research Database (Denmark)

Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik Clemmensen

2015-01-01

Switching valves experience opposing fluid forces due to movement of the moving member itself, as the surrounding fluid volume must move to accommodate the movement. This movement-induced fluid force may be divided into three main components; the added mass term, the viscous term and the socalled...... history term. For general valve geometries there are no simple solution to either of these terms. During development and design of such switching valves, it is therefore, common practice to use simple models to describe the opposing fluid forces, neglecting all but the viscous term which is determined...... based on shearing areas and venting channels. For fast acting valves the opposing fluid force may retard the valve performance significantly, if appropriate measures are not taken during the valve design. Unsteady Computational Fluid Dynamics (CFD) simulations are available to simulate the total fluid...

Valve monitoring ITI-MOVATS

International Nuclear Information System (INIS)

Moureau, S.

1993-01-01

ITI-MOVATS provides a wide range of test devices to monitor the performance of valves: motor operated gate or globe valve, butterfly valve, air operated valve, and check valve. The ITI-MOVATS testing equipment is used in the following three areas: actuator setup/baseline testing, periodic/post-maintenance testing, and differential pressure testing. The parameters typically measured with the MOVATS diagnostic system as well as the devices used to measure them are described. (Z.S.)

The nordic aortic valve intervention (NOTION) trial comparing transcatheter versus surgical valve implantation

DEFF Research Database (Denmark)

Thyregod, Hans Gustav; Søndergaard, Lars; Ihlemann, Nikolaj

2013-01-01

Degenerative aortic valve (AV) stenosis is the most prevalent heart valve disease in the western world. Surgical aortic valve replacement (SAVR) has until recently been the standard of treatment for patients with severe AV stenosis. Whether transcatheter aortic valve implantation (TAVI) can...

Anatomic, histopathologic, and echocardiographic features in a dog with an atypical pulmonary valve stenosis with a fibrous band of tissue and a patent ductus arteriosus.

Science.gov (United States)

Yoon, Hakyoung; Kim, Jaehwan; Nahm, Sang-Soep; Eom, Kidong

2017-07-11

Congenital pulmonary valve stenosis and patent ductus arteriosus are common congenital heart defects in dogs. However, concurrence of atypical pulmonary valve stenosis and patent ductus arteriosus is uncommon. This report describes the anatomic, histopathologic, and echocardiographic features in a dog with concomitant pulmonary valve stenosis and patent ductus arteriosus with atypical pulmonary valve dysplasia that included a fibrous band of tissue. A 1.5-year-old intact female Chihuahua dog weighing 3.3 kg presented with a continuous grade VI cardiac murmur, poor exercise tolerance, and an intermittent cough. Echocardiography indicated pulmonary valve stenosis, a thickened dysplastic valve without annular hypoplasia, and a type IIA patent ductus arteriosus. The pulmonary valve was thick line-shaped in systole and dome-shaped towards the right ventricular outflow tract in diastole. The dog suffered a fatal cardiac arrest during an attempted balloon pulmonary valvuloplasty. Necropsy revealed pulmonary valve dysplasia, commissural fusion, and incomplete opening and closing of the pulmonary valve because of a fibrous band of tissue causing adhesion between the right ventricular outflow tract and the dysplastic intermediate cusp of the valve. A fibrous band of tissue between the right ventricular outflow track and the pulmonary valve should be considered as a cause of pulmonary valve stenosis. Pulmonary valve stenosis and patent ductus arteriosus can have conflicting effects on diastolic and systolic dysfunction, respectively. Therefore, beta-blockers should always be used carefully, particularly in patients with a heart defect where there is concern about left ventricular systolic function.

Fluid control valves

International Nuclear Information System (INIS)

Rankin, J.

1980-01-01

A fluid control valve is described in which it is not necessary to insert a hand or a tool into the housing to remove the valve seat. Such a valve is particularly suitable for the control of radioactive fluids since maintenance by remote control is possible. (UK)

What Is Heart Valve Surgery?

Science.gov (United States)

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

What Is Heart Valve Disease?

Science.gov (United States)

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

HMGB1 and Histones Play a Significant Role in Inducing Systemic Inflammation and Multiple Organ Dysfunctions in Severe Acute Pancreatitis

Directory of Open Access Journals (Sweden)

Runkuan Yang

2017-01-01

Full Text Available Severe acute pancreatitis (SAP starts as a local inflammation of pancreatic tissue that induces the development of multiple extrapancreatic organs dysfunction; however, the underlying mechanisms are still not clear. Ischemia-reperfusion, circulating inflammatory cytokines, and possible bile cytokines significantly contribute to gut mucosal injury and intestinal bacterial translocation (BT during SAP. Circulating HMGB1 level is significantly increased in SAP patients and HMGB1 is an important factor that mediates (at least partly gut BT during SAP. Gut BT plays a critical role in triggering/inducing systemic inflammation/sepsis in critical illness, and profound systemic inflammatory response syndrome (SIRS can lead to multiple organ dysfunction syndrome (MODS during SAP, and systemic inflammation with multiorgan dysfunction is the cause of death in experimental SAP. Therefore, HMGB1 is an important factor that links gut BT and systemic inflammation. Furthermore, HMGB1 significantly contributes to multiple organ injuries. The SAP patients also have significantly increased circulating histones and cell-free DNAs levels, which can reflect the disease severity and contribute to multiple organ injuries in SAP. Hepatic Kupffer cells (KCs are the predominant source of circulating inflammatory cytokines in SAP, and new evidence indicates that hepatocyte is another important source of circulating HMGB1 in SAP; therefore, treating the liver injury is important in SAP.

Relief valve testing study

International Nuclear Information System (INIS)

BROMM, R.D.

2001-01-01

Reclosing pressure-actuated valves, commonly called relief valves, are designed to relieve system pressure once it reaches the set point of the valve. They generally operate either proportional to the differential between their set pressure and the system pressure (gradual lift) or by rapidly opening fully when the set pressure is reached (pop action). A pop action valve allows the maximum fluid flow through the valve when the set pressure is reached. A gradual lift valve allows fluid flow in proportion to how much the system pressure has exceeded the set pressure of the valve (in the case of pressure relief) or has decreased below the set pressure (vacuum relief). These valves are used to protect systems from over and under pressurization. They are used on boilers, pressure vessels, piping systems and vacuum systems to prevent catastrophic failures of these systems, which can happen if they are under or over pressurized beyond the material tolerances. The construction of these valves ranges from extreme precision of less than a psi tolerance and a very short lifetime to extremely robust construction such as those used on historic railroad steam engines that are designed operate many times a day without changing their set pressure when the engines are operating. Relief valves can be designed to be immune to the effects of back pressure or to be vulnerable to it. Which type of valve to use depends upon the design requirements of the system

Comparative study between CardiaMed valves (freely floating valve leaflets versus St. Jude Medical (fixed valve leaflets in mitral valve replacement surgery

Directory of Open Access Journals (Sweden)

Mostafa Ahmed

2017-09-01

Conclusions: CardiaMed freely floating leaflet prostheses showed good hemodynamic characteristics. The prosthesis adequately corrects hemodynamics and is safe and no worse than the St. Jude Medical valve in the mitral valve position.

Face-Sealing Butterfly Valve

Science.gov (United States)

Tervo, John N.

1992-01-01

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

Re-operation for aortic and mitral prosthetic dysfunctions.

Science.gov (United States)

Kaul, T K; Sastry, M R; Mercer, J L; Meade, J B

1985-01-01

The overall incidence of re-operation and prosthetic valve endocarditis was low in the present series as mechanical prostheses were used predominantly. The prosthetic dysfunctions were less frequent following the primary implantation with Bjork Shiley prostheses, but high operative risk was associated with the clotted Bjork Shiley prostheses. We also had unusual experience of strut fracture and sticking of Bjork Shiley discs in the closed position in both aortic and mitral positions. The early deaths were nil since the use of cardioplegic protection. Intra-operative bleeding due to adhesions can be minimised by using synthetic or heterologous pericardium during the primary operation.

Transapical JenaValve in a patient with mechanical mitral valve prosthesis.

LENUS (Irish Health Repository)

O' Sullivan, Katie E

2014-01-29

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

European supply chain for valve springs

Energy Technology Data Exchange (ETDEWEB)

Barthold, G. [Scherdel GmbH, Marktredwitz (Germany); Thureborn, D.; Hallberg, M. [Haldex Garphyttan AB (Sweden); Janssen, P. [Mittal Steel Ruhrort GmbH / Mittal Steel Hochfeld GmbH (Germany)

2005-07-01

Forced by the Kobe earthquake in 1995 and the lack of valve spring steel on the world market due to damages of the Kobe steel plant, the development of a European supply chain has been sped up. End of 1994 a super clean valve spring steel with a reasonable quality from a European source was available. A strong relationship between the steel producer (Mittal), the wire manufacturer (Haldex Garphyttan) and the spring maker (Scherdel) was established. A working group of the three companies holds meetings on a regular basis to discuss quality and development issues. Over the last years the supply chain has achieved significant improvements in terms of cleanliness and decarburisation of the wire rod. The continuous common advancement of the valve spring quality has enabled the valve spring failures in the field to be reduced to < 0.1 ppm. The development and market launch of new grades has been prepared. (orig.)

Burden of Sexual Dysfunction.

Science.gov (United States)

Balon, Richard

2017-01-02

Similar to the burden of other diseases, the burden of sexual dysfunction has not been systematically studied. However, there is growing evidence of various burdens (e.g., economic, symptomatic, humanistic) among patients suffering from sexual dysfunctions. The burden of sexual dysfunction has been studied a bit more often in men, namely the burden of erectile dysfunction (ED), premature ejaculation (PE) and testosterone deficiency syndrome (TDS). Erectile dysfunction is frequently associated with chronic conditions such as cardiovascular disease, diabetes, and depression. These conditions could go undiagnosed, and ED could be a marker of those diseases. The only available report from the United Kingdom estimated the total economic burden of ED at £53 million annually in terms of direct costs and lost productivity. The burden of PE includes significant psychological distress: anxiety, depression, lack of sexual confidence, poor self-esteem, impaired quality of life, and interpersonal difficulties. Some suggest that increase in female sexual dysfunction is associated with partner's PE, in addition to significant interpersonal difficulties. The burden of TDS includes depression, sexual dysfunction, mild cognitive impairment, and osteoporosis. One UK estimate of the economic burden of female sexual dysfunctions demonstrated that the average cost per patient was higher than the per annum cost of ED. There are no data on burden of paraphilic disorders. The burden of sexual dysfunctions is underappreciated and not well studied, yet it is significant for both the patients and the society.

Pomegranate Supplementation Protects against Memory Dysfunction after Heart Surgery: A Pilot Study

Directory of Open Access Journals (Sweden)

Susan A. Ropacki

2013-01-01

Full Text Available Memory dysfunction is a common complaint following heart surgery and may be related to a diffuse ischemic state induced by microemboli dislodged during the procedure. Ischemia can induce damage by a number of mechanisms, including oxidative stress. Because pomegranates contain a variety of polyphenols with antioxidant and other potentially beneficial effects, we tested whether supplementation with a pomegranate extract before and after heart surgery could protect against postoperative cognitive dysfunction. Patients undergoing elective coronary artery bypass graft and/or valve surgery were given either 2 g of pomegranate extract (in 2 POMx pills or placebo (pills containing no pomegranate ingredients per day from one week before surgery to 6 weeks after surgery. The patients were also administered a battery of neuropsychological tests to assess memory function at 1 week before surgery (baseline, 2 weeks after surgery, and 6 weeks after surgery. The placebo group had significant deficits in postsurgery memory retention, and the pomegranate treatment not only protected against this effect, but also actually improved memory retention performance for up to 6 weeks after surgery as compared to presurgery baseline performance.

Butterfly valves for seawater

International Nuclear Information System (INIS)

Yamanaka, Katsuto

1991-01-01

Recently in thermal and nuclear power stations and chemical plants which have become large capacity, large quantity of cooling water is required, and mostly seawater is utilized. In these cooling water systems, considering thermal efficiency and economy, the pipings become complex, and various control functions are demanded. For the purpose, the installation of shut-off valves and control valves for pipings is necessary. The various types of valves have been employed, and in particular, butterfly valves have many merits in their function, size, structure, operation, maintenance, usable period, price and so on. The corrosion behavior of seawater is complicated due to the pollution of seawater, therefore, the environment of the valves used for seawater became severe. The structure and the features of the butterfly valves for seawater, the change of the structure of the butterfly valves for seawater and the checkup of the butterfly valves for seawater are reported. The corrosion of metallic materials is complicatedly different due to the locating condition of plants, the state of pipings and the condition of use. The corrosion countermeasures for butterfly valves must be examined from the synthetic viewpoints. (K.I.)

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

Science.gov (United States)

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) valve survival (IOPendophthalmitis 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%.

Environmental qualification testing of TFE valve components

International Nuclear Information System (INIS)

Eyvindson, A.; Krasinski, W.; McCutcheon, R.

1997-01-01

Valves containing tetrafluoroethylene (TFE) components are being used in many CANDU Nuclear Generating Stations. However, some concerns remain about the performance of TFE after exposure to high levels of radiation. Stations must therefore ensure that such valves perform reliably after being exposed to postulated accident radiation dose levels. The current Ontario Hydro Environmental Qualification [EQ] program specifies much higher postulated radiation exposure than the original design, to account for conditions following a LOCA. Initial assessments indicated that Teflon components would require replacement. Proof of acceptable performance can remove the need for large scale replacement, avoiding a significant cost penalty and preserving benefits due to the superior performance of TFE-based seals. A test program was undertaken at Chalk River Laboratories (CRL) to investigate the performance of three valves after irradiation to 10 Mrad. Such valves are currently used at the Bruce B Nuclear Generating Station. Each contains TFE packing rings; one also has TFE seats. Two of the valves are used in the ECIS recovery system, while the third is used for instrumentation loop isolation or as drain valves. All are exposed to little or no radiation during normal use. Based on the results of the tests, all the valves tested will still meet functional and performance requirements after the TFE components have been exposed to 10 Mrad of irradiation. (author)

Supra-annular valve strategy for an early degenerated transcatheter balloon-expandable heart valve.

Science.gov (United States)

Kamioka, Norihiko; Caughron, Hope; Corrigan, Frank; Block, Peter; Babaliaros, Vasilis

2018-01-23

Currently, there are no recommendations regarding the selection of valve type for a transcatheter heart valve (THV)-in-THV procedure. A supra-annular valve design may be superior in that it results in a larger effective orifice area and may have a lower chance of valve thrombosis after THV-in-THV. In this report, we describe the use of a supra-annular valve strategy for an early degenerated THV. © 2018 Wiley Periodicals, Inc.

Remote actuated valve implant

Science.gov (United States)

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

2014-02-25

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

Mitral valve prolapse and hyperthyroidism: effect of patient selection.

Science.gov (United States)

Zullo, M A; Devereux, R B; Kramer-Fox, R; Lutas, E M; Brown, W T

1985-11-01

Patients with mitral valve prolapse and hyperthyroidism have common symptoms; the most outstanding symptom is palpitation. To determine whether or not common symptoms contributed to the reported association of these conditions, we evaluated 220 patients with symptomatic mitral valve prolapse and 216 first-degree relatives in 72 families; 65 relatives with mitral valve prolapse and 151 relatives without mitral valve prolapse, all greater than or equal to 16 years of age. Thirty subjects, aged 49 +/- 13 years (p less than 0.025 vs entire study group), had thyroid disease (23 subjects had definite thyroid disease, seven subjects had probable); 27 of 30 subjects with thyroid disease (90%) were female (p less than 0.005). The age- and sex-adjusted prevalence of hyperthyroidism was significantly higher in probands with mitral valve prolapse than in family members without mitral valve prolapse (3.5% vs 0%, p = 0.03), while an intermediate prevalence of hyperthyroidism (2.2%) was observed in family members with mitral valve prolapse. Thus, the prevalence of hyperthyroidism is increased among symptomatic patients with mitral valve prolapse as compared to family members without mitral valve prolapse, but the prevalence of thyroid conditions is similar among family members with or without this condition. These findings are explained by the effect of common symptoms on clinical detection of both mitral valve prolapse and hyperthyroidism.

The Fluid Mechanics of Transcatheter Heart Valve Leaflet Thrombosis in the Neosinus.

Science.gov (United States)

Midha, Prem A; Raghav, Vrishank; Sharma, Rahul; Condado, Jose F; Okafor, Ikechukwu U; Rami, Tanya; Kumar, Gautam; Thourani, Vinod H; Jilaihawi, Hasan; Babaliaros, Vasilis; Makkar, Raj R; Yoganathan, Ajit P

2017-10-24

Transcatheter heart valve (THV) thrombosis has been increasingly reported. In these studies, thrombus quantification has been based on a 2-dimensional assessment of a 3-dimensional phenomenon. Postprocedural, 4-dimensional, volume-rendered CT data of patients with CoreValve, Evolut R, and SAPIEN 3 transcatheter aortic valve replacement enrolled in the RESOLVE study (Assessment of Transcatheter and Surgical Aortic Bioprosthetic Valve Dysfunction With Multimodality Imaging and Its Treatment with Anticoagulation) were included in this analysis. Patients on anticoagulation were excluded. SAPIEN 3 and CoreValve/Evolut R patients with and without hypoattenuated leaflet thickening were included to study differences between groups. Patients were classified as having THV thrombosis if there was any evidence of hypoattenuated leaflet thickening. Anatomic and THV deployment geometries were analyzed, and thrombus volumes were computed through manual 3-dimensional reconstruction. We aimed to identify and evaluate risk factors that contribute to THV thrombosis through the combination of retrospective clinical data analysis and in vitro imaging in the space between the native and THV leaflets (neosinus). SAPIEN 3 valves with leaflet thrombosis were on average 10% further expanded (by diameter) than those without (95.5±5.2% versus 85.4±3.9%; P <0.001). However, this relationship was not evident with the CoreValve/Evolut R. In CoreValve/Evolut Rs with thrombosis, the thrombus volume increased linearly with implant depth ( R 2 =0.7, P <0.001). This finding was not seen in the SAPIEN 3. The in vitro analysis showed that a supraannular THV deployment resulted in a nearly 7-fold decrease in stagnation zone size (velocities <0.1 m/s) when compared with an intraannular deployment. In addition, the in vitro model indicated that the size of the stagnation zone increased as cardiac output decreased. Although transcatheter aortic valve replacement thrombosis is a multifactorial process

Modeling valve leakage

International Nuclear Information System (INIS)

Bell, S.R.; Rohrscheib, R.

1994-01-01

The American Society of Mechanical Engineers (ASME) Code requires individual valve leakage testing for Category A valves. Although the U.S. Nuclear Regulatory Commission (USNRC) has recognized that it is more appropriate to test containment isolation valves in groups, as allowed by 10 CFR 50, Appendix J, a utility seeking relief from these Code requirements must provide technical justification for the relief and establish a conservative alternate acceptance criteria. In order to provide technical justification for group testing of containment isolation valves, Illinois Power developed a calculation (model) for determining the size of a leakage pathway in a valve disc or seat for a given leakage rate. The model was verified experimentally by machining leakage pathways of known size and then measuring the leakage and comparing this value to the calculated value. For the range of values typical of leakage rate testing, the correlation between the experimental values and calculated values was quote good. Based upon these results, Illinois Power established a conservative acceptance criteria for all valves in the inservice testing (IST) program and was granted relief by the USNRC from the individual leakage testing requirements of the ASME Code. This paper presents the results of Illinois Power's work in the area of valve leakage rate testing

Outlet strut fracture of Björk-Shiley convexo-concave valves: can valve-manufacturing characteristics explain the risk?

Science.gov (United States)

Omar, R Z; Morton, L S; Beirne, M; Blot, W J; Lawford, P V; Hose, R; Taylor, K M

2001-06-01

Björk-Shiley 60 degrees convexo-concave prosthetic heart valves (Shiley, Inc, Irvine, Calif, a subsidiary of Pfizer, Inc) continue to be a concern for approximately 35,000 nonexplanted patients worldwide, with approximately 600 events reported to the manufacturer to date. Fractures of the outlet struts of the valves began to appear in the early 1980s and have continued to the present, but their causes are only partially understood. A matched case-control study was conducted evaluating manufacturing records for 52 valves with outlet strut fractures and 248 control subjects matched for age at implantation, valve size, and valve position. In addition to the risk factors recognized as determinants of outlet strut fracture, the United Kingdom case-control study has observed 7- to 9-fold increased risk with performance of multiple hook deflection tests. This test was performed more than once, usually after rework on the valve. Six valves in this study underwent multiple hook deflection tests, of which 4 experienced an outlet strut fracture. Cracks and further rework were noted for these valves. Significant associations were also observed between outlet strut fracture and disc-to-strut gap measurements taken before the attachment of the sewing ring. It is our view that a combination of factors related to valve design, manufacturing process, and patient characteristics are responsible for outlet strut fractures of Björk-Shiley convexo-concave valves. Multiple hook deflection tests have emerged as a potential new risk factor for outlet strut fracture in both The Netherlands and the United Kingdom. This factor appears to be correlated with the presence of other abnormalities. A further study is needed to investigate the factors correlated with multiple hook deflection tests. On confirmation of risk, the presence of multiple hook deflection tests may be added to equations, quantifying the risk of outlet strut fracture for comparison against risk of mortality and serious

Use of a valve operation test and evaluation system to enhance valve reliability

International Nuclear Information System (INIS)

Lowry, D.A.

1990-01-01

Power plant owners have emphasized the need for assuring safe, reliable operation of valves. While most valves must simply open or close, the mechanisms involved can be quite complex. Motor operated valves (MOVs) must be properly adjusted to assure operability. Individual operator components determine the performance of the entire MOV. Failure in MOVs could cripple or shut down a unit. Thus, a complete valve program consisting of design reviews, operational testing, and preventive and predictive maintenance activities will enhance an owner's confidence level that his valves win operate as expected. Liberty's Valve Operation Test and Evaluation System (VOTES) accurately measures stein thrust without intruding on valve operation. Since mounting a strain gage to a valve stem is a desirable but impractical way of obtaining precise stem thrust, Liberty developed a method to obtain identical data by placing a strain gage sensor on the valve yoke. VOTES provides information which effectively eliminates costly, unscheduled downtime. This paper presents the results of infield VOTES testing. The system's proven ability to identify and characterize actuator and valve performance is demonstrated. Specific topics of discussion include the ability of VOTES to ease a utility's IE Bulletin 8543 concerns and conclusively diagnose MOV components. Data from static and differential pressure testing are presented. Technical, operational, and financial advantages resulting from VOTES technology are explored in detail

Multiple-port valve

International Nuclear Information System (INIS)

Doody, T.J.

1978-01-01

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

Nuclear reactor steam depressurization valve

International Nuclear Information System (INIS)

Moore, G.L.

1991-01-01

This patent describes improvement in a nuclear reactor plant, an improved steam depressurization valve positioned intermediate along a steam discharge pipe for controlling the venting of steam pressure from the reactor through the pipe. The improvement comprises: a housing including a domed cover forming a chamber and having a partition plate dividing the chamber into a fluid pressure activation compartment and a steam flow control compartment, the valve housing being provided with an inlet connection and an outlet connection in the steam flow control compartment, and a fluid duct in communication with a source of fluid pressure for operating the valve; a valve set mounted within the fluid flow control compartment comprising a cylindrical section surrounding the inlet connection with one end adjoining the connection and having a radially projecting flange at the other end with a contoured extended valve sealing flange provided with an annular valve sealing member, and a valve cylinder traversing the partition plate and reciprocally movable within an opening in the partition plate with one terminal and extending into the fluid pressure activation compartment and the other terminal end extending into the steam flow control compartment coaxially aligned with the valve seat surrounding the inlet connection, the valve cylinder being surrounded by two bellow fluid seals and provided with guides to inhibit lateral movement, an end of the valve cylinder extending into the fluid flow control compartment having a radially projecting flange substantially conterminous with the valve seat flange and having a contoured surface facing and complimentary to the contoured valve seating surface whereby the two contoured valve surfaces can meet in matching relationship, thus providing a pressure actuated reciprocatable valve member for making closing contact with the valve seat and withdrawing therefrom for opening fluid flow through the valve

Double-disc gate valve

International Nuclear Information System (INIS)

Wheatley, S.J.

1979-01-01

The invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewith, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separation of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve

Intro to Valve Guide Reconditioning. Automotive Mechanics. Valves. Instructor's Guide [and] Student Guide.

Science.gov (United States)

Horner, W.

This instructional package, one in a series of individualized instructional units on tools and techniques for repairing worn valve guides in motor vehicles, provides practical experience for students in working on cylinder heads. Covered in the module are reaming valve guides that are oversized to match a new oversized valve, reaming valve guides…

A review of historical check valve failure data

International Nuclear Information System (INIS)

Casada, D.A.; Todd, M.D.

1992-01-01

Check valve operating problems in recent years have resulted in significant operating transients, increased cost, and decreased system availability. In response, additional attention has been given to check valves by utilities, as well as the US Nuclear Regulatory Commission (NRC) and the American Society of Mechanical Engineers Operation and Maintenance Committee. All these organizations have the fundamental goal of ensuring reliable operation of check valves. A key ingredient of an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. Oak Ridge National Laboratory is currently conducting a detailed review of historical failure data available through the Institute of Nuclear Power Operation's Nuclear Plant Reliability Data System. The focus of the review is on check valve failures that have involved significant degradation of the valve internal parts. A variety of parameters are being considered during the review, including size, age, system of service, method of failure discovery, the affected valve parts, attributed causes, and corrective actions. This work is being carried out under the auspices of the NRC's Nuclear Plant Aging Research program. At this time, the study is approximately 50% complete. All failure records have been reviewed and categorized, and preliminary tabulation and correlation of data is underway. The bulk of the tabulation and correlation portion of the work is expected to be completed by the end of June 1992. A report draft is expected in the fall of 1992

Guide to prosthetic cardiac valves

International Nuclear Information System (INIS)

Morse, D.; Steiner, R.M.; Fernandez, J.

1985-01-01

This book contains 10 chapters. Some of the chapter titles are: The development of artificial heart valves: Introduction and historical perspective; The radiology of prosthetic heart valves; The evaluation of patients for prosthetic valve implantation; Pathology of cardiac valve replacement; and Bioengineering of mechanical and biological heart valve substitutes

The effect of nasopharyngoscopic biofeedback in patients with cleft palate and velopharyngeal dysfunction.

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Brunner, Monika; Stellzig-Eisenhauer, Angelika; Pröschel, Ute; Verres, Rolf; Komposch, Gerda

2005-11-01

To evaluate the immediate, long-term, and carry-over effects of nasopharyngoscopic biofeedback therapy in patients with cleft palate who exhibit velopharyngeal dysfunction (VPD). Pre- versus posttreatment and follow-up comparisons. Cleft palate center of the Heidelberg University Hospital, Heidelberg, Germany. Eleven patients with VPD who had received conventional speech therapy without showing significant improvement. A four-stage feedback procedure. The patients watched and evaluated their velopharyngeal (VP) valving during speech by an endoscopic image displayed on a video monitor. Two feedback sessions took place for every target sound. Mean occurrence of VP closure during speech sound production on different linguistic levels. Patients' self-perception was assessed by a questionnaire and speech diary. Significant improvement and stability of VP closure was noted. Mean occurrence of VP closure was 5% before therapy, 91% after two biofeedback sessions, and 86% in the follow-up after 6 months. Velopharyngeal dysfunction associated with compensatory articulation proved to be equally well trained as VPD on sounds with good articulatory placement. No significant difference was observed in the degree of improvement between phoneme-specific VPD and generalized VPD. The transfer to the level of words and sentences was successful and showed significant stability. The stability of VP closure for vowels was less than the stability for fricatives and stop sounds. Patients gained improved auditory and kinesthetic self-perception of their articulation. Nasopharyngoscopic biofeedback therapy proves to be a quick and effective method to change VPD. It shows stable results and carry-over effects.

Trans-apical aortic valve implantation in a patient with stentless valve degeneration.

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Kapetanakis, Emmanouil I; MacCarthy, Philip; Monaghan, Mark; Wendler, Olaf

2011-06-01

Trans-apical valve-in-valve trans-catheter aortic valve implantation (TAVI) has successfully been performed in selected, high-risk patients, who suffered prosthetic degeneration after aortic valve replacement using stented xenografts. We report the case of a 79-year-old male patient who underwent one of the first successful TAVIs in a failing stentless bioprosthesis. Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Vortex dynamics in Patient-Specific Stenotic Tricuspid and Bicuspid Aortic Valves pre- and post- Trans-catheter Aortic Valve Replacement

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Hatoum, Hoda; Dasi, Lakshmi Prasad

2017-11-01

Understanding blood flow related adverse complications such as leaflet thrombosis post-transcatheter aortic valve implantation (TAVI) requires a deeper understanding of how patient-specific anatomic and hemodynamic factors, and relative valve positioning dictate sinus vortex flow and stasis regions. High resolution time-resolved particle image velocimetry measurements were conducted in compliant and transparent 3D printed patient-specific models of stenotic bicuspid and tricuspid aortic valve roots from patients who underwent TAVI. Using Lagrangian particle tracking analysis of sinus vortex flows and probability distributions of residence time and blood damage indices we show that (a) patient specific modeling provides a more realistic assessment of TAVI flows, (b) TAVI deployment alters sinus flow patterns by significantly decreasing sinus velocity and vorticity, and (c) relative valve positioning can control critical vortex structures that may explain preferential leaflet thrombosis corresponding to separated flow recirculation, secondary to valve jet vectoring relative to the aorta axis. This work provides new methods and understanding of the spatio-temporal aortic sinus vortex dynamics in post TAVI pathology. This study was supported by the Ohio State University DHLRI Trifit Challenge award.

Recommendations for the imaging assessment of prosthetic heart valves: a report from the European Association of Cardiovascular Imaging endorsed by the Chinese Society of Echocardiography, the Inter-American Society of Echocardiography, and the Brazilian Department of Cardiovascular Imaging.

Science.gov (United States)

Lancellotti, Patrizio; Pibarot, Philippe; Chambers, John; Edvardsen, Thor; Delgado, Victoria; Dulgheru, Raluca; Pepi, Mauro; Cosyns, Bernard; Dweck, Mark R; Garbi, Madalina; Magne, Julien; Nieman, Koen; Rosenhek, Raphael; Bernard, Anne; Lowenstein, Jorge; Vieira, Marcelo Luiz Campos; Rabischoffsky, Arnaldo; Vyhmeister, Rodrigo Hernández; Zhou, Xiao; Zhang, Yun; Zamorano, Jose-Luis; Habib, Gilbert

2016-06-01

Prosthetic heart valve (PHV) dysfunction is rare but potentially life-threatening. Although often challenging, establishing the exact cause of PHV dysfunction is essential to determine the appropriate treatment strategy. In clinical practice, a comprehensive approach that integrates several parameters of valve morphology and function assessed with 2D/3D transthoracic and transoesophageal echocardiography is a key to appropriately detect and quantitate PHV dysfunction. Cinefluoroscopy, multidetector computed tomography, cardiac magnetic resonance imaging, and to a lesser extent, nuclear imaging are complementary tools for the diagnosis and management of PHV complications. The present document provides recommendations for the use of multimodality imaging in the assessment of PHVs. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

Early clinical outcome of aortic transcatheter valve-in-valve implantation in the Nordic countries

DEFF Research Database (Denmark)

Ihlberg, Leo; Nissen, Henrik Hoffmann; Nielsen, Niels Erik

2013-01-01

Transcatheter valve-in-valve implantation has emerged as an option, in addition to reoperative surgical aortic valve replacement, to treat failed biologic heart valve substitutes. However, the clinical experience with this approach is still limited. We report the comprehensive experience...

Comparison of biatrial and left atrial radiofrequency ablation in patients with heart valves diseases

Directory of Open Access Journals (Sweden)

А. В. Богачев-прокофьев

2015-10-01

Full Text Available We analysed results of left atrial and biatrial anatomic scheme of radiofrequency (RF ablation of the atria in patients with valvular heart. From 2007 to 2011, RF ablation procedure performed 283 patients with atrial fibrillation and heart valve disease. Patients were divided into two groups - group I performed a complete circuit biatrial procedure (procedure maze IV - 131 patients, in group II only ablation of the left atrium -152 patients. Most of the patients had long-term persistent AF. The main problem of early postoperative period is dysfunction of pacemaker complex, which observed in 64.9% and 50.7% patients for group I and II, respectively (p = 0.031. Permanent dysfunction of pacemaker complex required implantation of permanent pacemaker (9.2% and 4.6% of cases for group I and II, respectively, p = 0,023. Predictors of dysfunction of the pacemaker complex were biatrial execution method and duration of AF. Freedom from AF and AT during 36 months after surgery was 80.4% for patients in group I and 78.5% for patients in group II, with no statistically significant difference (log-rank test, p = 0.621. Atrial transport function has not revealed that the active fraction of the right atrium was 29.8% higher than in group II in the early postoperative phase and by 17.9% in the long term, with no difference between groups for the left atrium has been received.

Nuclear valves latest development

International Nuclear Information System (INIS)

Isaac, F.; Monier, M.

1993-01-01

In the frame of Nuclear Power Plant upgrade (Emergency Power Supply and Emergency Core Cooling), Westinghouse had to face a new valve design philosophy specially for motor operated valves. The valves have to been designed to resist any operating conditions, postulated accident or loss of control. The requirements for motor operated valves are listed and the selected model and related upgrading explained. As part of plant upgrade and valves replacement, Westinghouse has sponsored alternative hardfacing research programme. Two types of materials have been investigated: nickel base alloys and iron base alloys. Programme requirements and test results are given. A new globe valve model (On-Off or regulating) is described developed by Alsthom Velan permitting the seat replacement in less than 10 min. (Z.S.) 2 figs

Magnetic Check Valve

Science.gov (United States)

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

1994-01-01

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

Left atrial dysfunction in type 2 diabetes mellitus: insights from cardiac MRI

Energy Technology Data Exchange (ETDEWEB)

Graca, Bruno; Donato, Paulo; Caseiro-Alves, Filipe [University of Coimbra, Faculty of Medicine, Coimbra (Portugal); Coimbra' s Hospital Centre and University, Medical Imaging Department, Coimbra (Portugal); Joao Ferreira, Maria [University of Coimbra, Faculty of Medicine, Coimbra (Portugal); Coimbra' s Hospital Centre and University, Cardiology Department, Coimbra (Portugal); Gomes, Leonor [University of Coimbra, Faculty of Medicine, Coimbra (Portugal); Coimbra' s Hospital Centre and University, Endocrinology Department, Coimbra (Portugal); Castelo-Branco, Miguel [University of Coimbra, Faculty of Medicine, Coimbra (Portugal)

2014-11-15

The left atrium (LA) modulates left ventricular filling through reservoir, conduit and booster pump functions. Only limited data exist on LA involvement in type 2 diabetes mellitus (DM2). This study sought to assess LA function in asymptomatic DM2 with cardiac MRI. We hypothesized that cardiac MRI can detect LA dysfunction in asymptomatic DM2. Forty-five patients with asymptomatic DM2 and 24 normoglycaemic controls were studied. MRI cine imaging was performed to measure LA maximal and minimal volumes. A flow-sensitive phase-contrast gradient-echo sequence was used for flow measurements perpendicular to the orifice of the mitral valve, to quantify active LA stroke volume. LA total, passive and active emptying volumes and fractions were calculated. LA reservoir function, namely LA total ejection fraction, was significantly greater in controls compared to patients with DM2 (62.2 ± 5.2 vs 57.0 ± 7.6 %, P = 0.004). LA passive ejection fraction was also greater in the controls (26.2 ± 9.5 vs 16.1 ± 11.0 %, P < 0.001). Regarding parameters of LA booster pump function, LA active ejection fraction was not significantly different between groups. DM2 was demonstrated to be an independent determinant of LA function. Cardiac MRI enables the detection of LA dysfunction in asymptomatic DM2, characterized by a reduction in LA reservoir and conduit functions. (orig.)

Effects of valve timing, valve lift and exhaust backpressure on performance and gas exchanging of a two-stroke GDI engine with overhead valves

International Nuclear Information System (INIS)

Dalla Nora, Macklini; Lanzanova, Thompson Diórdinis Metzka; Zhao, Hua

2016-01-01

Highlights: • Two-stroke operation was achieved in a four-valve direct injection gasoline engine. • Shorter valve opening durations improved torque at lower engine speeds. • The longer the valve opening duration, the lower was the air trapping efficiency. • Higher exhaust backpressure and lower valve lift reduced the compressor work. - Abstract: The current demand for fuel efficient and lightweight powertrains, particularly for application in downsized and hybrid electric vehicles, has renewed the interest in two-stroke engines. In this framework, an overhead four-valve spark-ignition gasoline engine was modified to run in the two-stroke cycle. The scavenging process took place during a long valve overlap period around bottom dead centre at each crankshaft revolution. Boosted intake air was externally supplied at a constant pressure and gasoline was directly injected into the cylinder after valve closure. Intake and exhaust valve timings and lifts were independently varied through an electrohydraulic valve train, so their effects on engine performance and gas exchanging were investigated at 800 rpm and 2000 rpm. Different exhaust backpressures were also evaluated by means of exhaust throttling. Air trapping efficiency, charging efficiency and scavenge ratio were calculated based on air and fuel flow rates, and exhaust oxygen concentration at fuel rich conditions. The results indicated that longer intake and exhaust valve opening durations increased the charge purity and hence torque at higher engine speeds. At lower speeds, although, shorter valve opening durations increased air trapping efficiency and reduced the estimated supercharger power consumption due to lower air short-circuiting. A strong correlation was found between torque and charging efficiency, while air trapping efficiency was more associated to exhaust valve opening duration. The application of exhaust backpressure, as well as lower intake/exhaust valve lifts, made it possible to increase

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

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Rajesh Janardhanan

2016-05-01

Full Text Available In intravenous drug abusers, infective endocarditis usually involves right-sided valves, with Staphylococcus aureus being the most common etiologic agent. We present a patient who is an intravenous drug abuser with left-sided (aortic valve endocarditis caused by Enterococcus faecalis who subsequently developed an anterior mitral valve aneurysm, which is an exceedingly rare complication. A systematic literature search was conducted which identified only five reported cases in the literature of mitral valve aneurysmal rupture in the setting of E. faecalis endocarditis. Real-time 3D-transesophageal echocardiography was critical in making an accurate diagnosis leading to timely intervention. Learning objectives: • Early recognition of a mitral valve aneurysm (MVA is important because it may rupture and produce catastrophic mitral regurgitation (MR in an already seriously ill patient requiring emergency surgery, or it may be overlooked at the time of aortic valve replacement (AVR. • Real-time 3D-transesophageal echocardiography (RT-3DTEE is much more advanced and accurate than transthoracic echocardiography for the diagnosis and management of MVA.

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

Science.gov (United States)

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

2016-03-01

SummaryIn intravenous drug abusers, infective endocarditis usually involves right-sided valves, with Staphylococcus aureus being the most common etiologic agent. We present a patient who is an intravenous drug abuser with left-sided (aortic valve) endocarditis caused by Enterococcus faecalis who subsequently developed an anterior mitral valve aneurysm, which is an exceedingly rare complication. A systematic literature search was conducted which identified only five reported cases in the literature of mitral valve aneurysmal rupture in the setting of E. faecalis endocarditis. Real-time 3D-transesophageal echocardiography was critical in making an accurate diagnosis leading to timely intervention. Early recognition of a mitral valve aneurysm (MVA) is important because it may rupture and produce catastrophic mitral regurgitation (MR) in an already seriously ill patient requiring emergency surgery, or it may be overlooked at the time of aortic valve replacement (AVR).Real-time 3D-transesophageal echocardiography (RT-3DTEE) is much more advanced and accurate than transthoracic echocardiography for the diagnosis and management of MVA. © 2016 The authors.

Aortic valve-sparing surgery in Marfan syndrome.

Science.gov (United States)

Nachum, Eyal; Shinfeld, Amichay; Kogan, Alexander; Preisman, Sergey; Levin, Shany; Raanani, Ehud

2013-08-01

Patients with Marfan syndrome are referred for cardiac surgery due to root aneurysm with or without aortic valve regurgitation. Because these patients are young and frequently present with normal-appearing aortic cusps, valve sparing is often recommended. However, due to the genetic nature of the disease, the durability of such surgery remains uncertain. Between February 2004 and June 2012, 100 patients in our department suffering from aortic aneurysm with aortic valve regurgitation underwent elective aortic valve-sparing surgery. Of them, 30 had Marfan syndrome, were significantly younger (30 +/- 13 vs. 53 +/- 16 years), and had a higher percentage of root aneurysm, compared with ascending aorta aneurysm in their non-Marfan counterparts. We evaluated the safety, durability, clinical and echocardiographic mid-term results of these patients. While no early deaths were reported in either group, there were a few major early complications in both groups. At follow-up (reaching 8 years with a mean of 34 +/- 26 months) there were no late deaths, and few major late complications in the Marfan group. Altogether, 96% and 78% of the patients were in New York Heart Association functional class I-II in the Marfan and non-Marfan groups respectively. None of the Marfan patients needed reoperation on the aortic valve. Freedom from recurrent aortic valve regurgitation > 3+ was 94% in the Marfan patients. Aortic valve-sparing surgery in Marfan symdrome patients is safe and yields good mid-term clinical outcomes.

Transcatheter Aortic Valve Replacement for Degenerative Bioprosthetic Surgical Valves

DEFF Research Database (Denmark)

Dvir, Danny; Webb, John; Brecker, Stephen

2012-01-01

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

Aperture Valve for the Mars Organic Molecule Analyzer (MOMA)

Science.gov (United States)

Hakun, Claef F.; Engler, Charles D.; Barber, Willie E.; Canham, John S.

2014-01-01

NASA's participation in the multi-nation ExoMars 2018 Rover mission includes a critical astrobiology Mass Spectrometer Instrument on the Rover called the Mars Organic Molecule Analyzer (MOMA). The Aperture Valve is a critical electromechanical valve used by the Mass Spectrometer to facilitate the transfer of ions from Martian soil to the Mass Spectrometer for analysis. The MOMA Aperture Valve development program will be discussed in terms of the Initial valve design and subsequent improvements that resulted from prototype testing. The Initial Aperture Valve concept seemed promising, based on calculations and perceived merits. However, performance results of this design were disappointing, due to delamination of TiN and DLC coatings applied to the Titanium base metals, causing debris from the coatings to seize the valve. While peer reviews and design trade studies are important forums to vet a concept design, results from testing should not be underestimated.Despite the lack of development progress to meet requirements, valuable information from weakness discovered in the Initial Valve design was used to develop a second, more robust Aperture valve. Based on a check-ball design, the ETU flight valve design resulted in significantly less surface area to create the seal. Moreover, PVD coatings were eliminated in favor of hardened, nonmagnetic corrosion resistant alloys. Test results were impressive, with the valve achieving five orders of magnitude better sealing leak rate over end of life requirements. Cycle life was equally impressive, achieving 280,000 cycles without failure.

Transcatheter aortic valve replacement

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... gov/ency/article/007684.htm Transcatheter aortic valve replacement To use the sharing features on this page, please enable JavaScript. Transcatheter aortic valve replacement (TAVR) is surgery to replace the aortic valve. ...

Overflow control valve

International Nuclear Information System (INIS)

Kessinger, B.A.; Hundal, R.; Parlak, E.A.

1982-01-01

An overflow control valve for use in a liquid sodium coolant pump tank which can be remotely engaged with and disengaged from the pump tank wall to thereby permit valve removal. An actuating shaft for controlling the valve also has means for operating a sliding cylinder against a spring to retract the cylinder from sealing contact with the pump tank nozzle. (author)

pH-Sensitive Hydrogel for Micro-Fluidic Valve

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Zhengzhi Yang

2012-07-01

Full Text Available The deformation behavior of a pH-sensitive hydrogel micro-fluidic valve system is investigated using inhomogeneous gel deformation theory, in which the fluid-structure interaction (FSI of the gel solid and fluid flow in the pipe is considered. We use a finite element method with a well adopted hydrogel constitutive equation, which is coded in commercial software, ABAQUS, to simulate the hydrogel valve swelling deformation, while FLUENT is adopted to model the fluid flow in the pipe of the hydrogel valve system. The study demonstrates that FSI significantly affects the gel swelling deformed shapes, fluid flow pressure and velocity patterns. FSI has to be considered in the study on fluid flow regulated by hydrogel microfluidic valve. The study provides a more accurate and adoptable model for future design of new pH-sensitive hydrogel valves, and also gives a useful guideline for further studies on hydrogel fluidic applications.

Surgical treatment of aortic valve endocarditis: a 26-year experience

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Taylan Adademir

2014-03-01

Full Text Available Objective: We have retrospectively analyzed the results of the operations made for aortic valve endocarditis in a single center in 26 years. Methods: From June 1985 to January 2011, 174 patients were operated for aortic valve endocarditis. One hundred and thirty-eight (79.3% patients were male and the mean age was 39.3±14.4 (9-77 years. Twenty-seven (15.5% patients had prosthetic valve endocarditis. The mean duration of follow-up was 7.3±4.2 years (0.1-18.2 adding up to a total of 1030.8 patient/years. Results: Two hundred and eighty-two procedures were performed. The most frequently performed procedure was aortic valve replacement with mechanical prosthesis (81.6%. In-hospital mortality occurred in 27 (15.5% cases. Postoperatively, 25 (14.4% patients had low cardiac output and 17 (9.8% heart block. The actuarial survival rates for 10 and 15 years were 74.6±3.7% and 61.1±10.3%, respectively. In-hospital mortality was found to be associated with female gender, emergency operation, postoperative renal failure and low cardiac output. The long term mortality was significantly associated with mitral valve involvement. Male gender was found to be a significant risk factor for recurrence in the follow-up. Conclusion: Surgery for aortic valve endocarditis has significant mortality. Emergency operation, female gender, postoperative renal failure and low cardiac output are significant risk factors. Risk for recurrence and need for reoperation is low.

Solution to valve failures at Braidwood induced by service water cavitation

International Nuclear Information System (INIS)

Ozol, J.; Schipiour, B.K.; Wix, J.E.

1994-01-01

Control valves throttle fluid from a high pressure to a lower pressure. On water systems, this throttling process may be accompanied by cavitation, which induces valve noise, vibration, and material damage. Extensive and significant caviation erosion has been experienced the last 10 years in most service water control valve bodies, downstream flanges, and reducers at Braidwood Station. There have been 40 different and distinct cavitation-induced failures in the service water system at Braidwood Station. These failures have created significant costs and continue to be a lingering source of operational maintenance costs to the Commonwealth Edison Company, which is incurring significant financial losses. It should be noted that almost all service water control valves experience some cavitation effects. Cavitation and cavitation damage are complex and elusive phenomena for which no single, simple analytical model exists. The purpose of this paper is to explain features of service water control valve cavitation failures and some of the solutions used by Commonwealth Edison at their six nuclear stations. The paper discusses the following: (1) Braidwood's history of erosion from cavitation; (2) Erosion-corrosion considerations; (3) The Instrument Society of America's valve sizing equations and how they relate to cavitation; (4) Methods to eliminate cavitation; (5) Corrective actions and practical approaches used by Commonwealth Edison to eliminate cavitation

Comparative study of Butterfly valves

International Nuclear Information System (INIS)

Galmes Belmonte, F.B.

1998-01-01

This work tries to justify the hydrodynamic butterfly valves performance, using the EPRI tests, results carried out in laboratory and in situ. This justification will be possible if: - The valves to study are similar - Their performance is calculated using EPRI's methodology Looking for this objective, the elements of the present work are: 1. Brief EPRI butterfly valve description it wild provide the factors which are necessary to define the butterfly valves similarity. 2. EPRI tests description and range of validation against test data definition. 3. Description of the spanish butterfly analyzed valves, and comparison with the EPRI performance results, to prove that this valves are similar to the EPRI test valves. In this way, it will not be necessary to carry out particular dynamic tests on the spanish valves to describe their hydrodynamic performance. (Author)

Fluid mechanics of heart valves.

Science.gov (United States)

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.

Intelligent Flow Control Valve

Science.gov (United States)

Kelley, Anthony R (Inventor)

2015-01-01

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

Experience with valves for PHWR reactors

International Nuclear Information System (INIS)

Narayan, K.; Mhetre, S.G.

1977-01-01

Material specifications and inspection and testing requirements of the valves meant for use in nuclear reactors are mentioned. In the heavy water systems (both primary and moderator) of a PHWR type reactor, the valves used are gate valves, globe valves, diaphragm valves, butterfly valves, check valves and relief valves. Their locations and functions they perform in the Rajasthan Atomic Power Station Unit-1 are described. Experience with them is given. The major problems encountered with them have been : (1) leakage from the stem seals and body bonnet joint, (2) leakage due to failure of diaphragm and/or washout of the packing and (3) malfunctioning. Measures taken to solve these are discussed. Finally a mention has been made of improved versions of valves, namely, metal diaphragm valve and inverted relief valve. (M.G.B.)

Association of aortic valve calcification severity with the degree of aortic regurgitation after transcatheter aortic valve implantation.

Science.gov (United States)

Koos, Ralf; Mahnken, Andreas Horst; Dohmen, Guido; Brehmer, Kathrin; Günther, Rolf W; Autschbach, Rüdiger; Marx, Nikolaus; Hoffmann, Rainer

2011-07-15

This study sought to examine a possible relationship between the severity of aortic valve calcification (AVC), the distribution of AVC and the degree of aortic valve regurgitation (AR) after transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS). 57 patients (22 men, 81 ± 5 years) with symptomatic AS and with a logistic EuroSCORE of 24 ± 12 were included. 38 patients (67%) received a third (18F)-generation CoreValve® aortic valve prosthesis, in 19 patients (33%) an Edwards SAPIEN™ prosthesis was implanted. Prior to TAVI dual-source computed tomography for assessment of AVC was performed. To determine the distribution of AVC the percentage of the calcium load of the most severely calcified cusp was calculated. After TAVI the degree of AR was determined by angiography and echocardiography. The severity of AR after TAVI was related to the severity and distribution of AVC. There was no association between the distribution of AVC and the degree of paravalvular AR after TAVI as assessed by angiography (r = -0.02, p = 0.88). Agatston AVC scores were significantly higher in patients with AR grade ≥ 3 (5055 ± 1753, n = 3) than in patients with AR grade AVC scores > 3000 were associated with a relevant paravalvular AR and showed a trend for increased need for second manoeuvres. There was a significant correlation between the severity of AVC and the degree of AR after AVR (r = 0.50, p AVC have an increased risk for a relevant AR after TAVI as well as a trend for increased need for additional procedures. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Biological aortic valve replacement: advantages and optimal indications of stentless compared to stented valve substitutes. A review.

Science.gov (United States)

Tavakoli, Reza; Danial, Pichoy; Oudjana, Ahmed Hamid; Jamshidi, Peiman; Gassmann, Max; Leprince, Pascal; Lebreton, Guillaume

2018-05-01

Controversy still surrounds the optimal biological valve substitute for aortic valve replacement. In light of the current literature, we review advantages and optimal indications of stentless compared to stented aortic bio-prostheses. Recent meta-analyses, prospective randomized controlled trials and retrospective studies comparing the most frequently used stentless and stented aortic bio-prostheses were analyzed. In the present review, the types and implantation techniques of the bio-prosthesis that are seldom taken into account by most studies and reviews were integrated in the interpretation of the relevant reports. For stentless aortic root bio-prostheses, full-root vs. sub-coronary implantation offered better early transvalvular gradients, effective orifice area and left ventricular mass regression as well as late freedom from structural valve deterioration in retrospective studies. Early mortality and morbidity did not differ between the stentless and stented aortic bio-prostheses. Early transvalvular gradients, effective orifice area and regression of left ventricular hypertrophy were significantly better for stentless, especially as full-root, compared to stented bio-prostheses. The long-term valve-related survival for stentless aortic root and Toronto SPV bio-prosthesis was as good as that for stented pericardial aortic bio-prostheses. For full-root configuration this survival advantage was statistically significant. There seems to be not one but different ideal biological valve substitutes for different subgroups of patients. In patients with small aortic root or exposed to prosthesis-patient mismatch full-root implantation of stentless bio-prostheses may better meet functional needs of individual patients. Longer follow-ups on newer generation of stented bio-prostheses are needed for comparison of their hemodynamic performance with stentless counterparts especially in full-root configuration.

Combined usage of inhaled and intravenous milrinone in pulmonary hypertension after heart valve surgery.

Science.gov (United States)

Carev, Mladen; Bulat, Cristijan; Karanović, Nenad; Lojpur, Mihajlo; Jercić, Antonio; Nenadić, Denis; Marovih, Zlatko; Husedzinović, Ino; Letica, Dalibor

2010-09-01

Secondary pulmonary hypertension is a frequent condition after heart valve surgery. It may significantly complicate the perioperative management and increase patients' morbidity and mortality. The treatment has not been yet completely defined principally because of lack of the selectivity of drugs for the pulmonary vasculature. The usage of inhaled milrinone could be the possible therapeutic option. Inodilator milrinone is commonly used intravenously for patients with pulmonary hypertension and ventricular dysfunction in cardiac surgery. The decrease in systemic vascular resistance frequently necessitates concomitant use of norepinephrine. Pulmonary vasodilators might be more effective and also devoid of potentially dangerous systemic side effects if applied by inhalation, thus acting predominantly on pulmonary circulation. There are only few reports of inhaled milrinone usage in adult post cardiac surgical patients. We reported 2 patients with severe pulmonary hypertension after valve surgery. Because of desperate clinical situation, we decided to use the combination of inhaled and intravenous milrinone. Inhaled milrinone was delivered by means of pneumatic medication nebulizer dissolved with saline in final concentration of 0.5 mg/ml. The nebulizer was attached to the inspiratory limb of the ventilator circuit, just before the Y-piece. We obtained satisfactory reduction in mean pulmonary artery pressure in both patients, and they were successfully extubated and discharged. Although it is a very small sample of patients, we conclude that the combination of inhaled and intravenous milrinone could be an effective treatment of secondary pulmonary hypertension in high-risk cardiac valve surgery patient. The exact indications for inhaled milrinone usage, optimal concentrations for this route, and the beginning and duration of treatment are yet to be determined.

Transcatheter Aortic Valve Implantation and Morbidity and Mortality-Related Factors: a 5-Year Experience in Brazil

Directory of Open Access Journals (Sweden)

André Luiz Silveira Souza

2016-01-01

Full Text Available Abstract Background: Transcatheter aortic valve implantation has become an option for high-surgical-risk patients with aortic valve disease. Objective: To evaluate the in-hospital and one-year follow-up outcomes of transcatheter aortic valve implantation. Methods: Prospective cohort study of transcatheter aortic valve implantation cases from July 2009 to February 2015. Analysis of clinical and procedural variables, correlating them with in-hospital and one-year mortality. Results: A total of 136 patients with a mean age of 83 years (80-87 underwent heart valve implantation; of these, 49% were women, 131 (96.3% had aortic stenosis, one (0.7% had aortic regurgitation and four (2.9% had prosthetic valve dysfunction. NYHA functional class was III or IV in 129 cases (94.8%. The baseline orifice area was 0.67 ± 0.17 cm2 and the mean left ventricular-aortic pressure gradient was 47.3±18.2 mmHg, with an STS score of 9.3% (4.8%-22.3%. The prostheses implanted were self-expanding in 97% of cases. Perioperative mortality was 1.5%; 30-day mortality, 5.9%; in-hospital mortality, 8.1%; and one-year mortality, 15.5%. Blood transfusion (relative risk of 54; p = 0.0003 and pulmonary arterial hypertension (relative risk of 5.3; p = 0.036 were predictive of in-hospital mortality. Peak C-reactive protein (relative risk of 1.8; p = 0.013 and blood transfusion (relative risk of 8.3; p = 0.0009 were predictive of 1-year mortality. At 30 days, 97% of patients were in NYHA functional class I/II; at one year, this figure reached 96%. Conclusion: Transcatheter aortic valve implantation was performed with a high success rate and low mortality. Blood transfusion was associated with higher in-hospital and one-year mortality. Peak C-reactive protein was associated with one-year mortality.

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

Science.gov (United States)

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

2016-01-01

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

Presentation, management, and outcome of posterior urethral valves in a Nigerian tertiary hospital.

Science.gov (United States)

Orumuah, Agbugui Jude; Oduagbon, Obarisiagbon Edwin

2015-01-01

Posterior urethral valves (PUV) remain the most common cause of bladder outlet obstruction and renal insufficiency in male children. The aim of this study was to evaluate the presentation, management, challenges, and outcome of the disease in a Nigerian tertiary health institution. Retrospectively, medical records of male children with a diagnosis of PUVs over a 10 year period (2003-2012) were retrieved. All data in relation to the study objectives were recorded and analyzed. A total of 44 patients was managed for PUV within the period. The mean age of presentation was 3.95 years with 56.8% of the patients presenting after the age of 1 year. Voiding dysfunction noted in 40 (91.0%) patients was the most common mode of presentation. The most common finding on physical examination was a palpable bladder while urinary tract infection noted in 23 (52.3%) patients was the most common complication noted. Abdominal ultrasonography revealed dilated posterior urethra in 16 (36.4%) cases, while micturating cystourethrogram revealed a dilated proximal urethra in all 35 cases in which it was done, diverticulum in 6 and vesicoureteric reflux in 9. The creatinine value at presentation ranged between 0.4 mg/dl and 4.0 mg/dl with a mean of 1.02 ± 0.93 mg/dl. Urethroscopy in 37 patients confirmed type I and type III PUV in 35 and 2 patients, respectively. Valve ablation with a diathermy bugbee electrode provided relief of obstructions in the 37 patients who underwent the procedure without any significant immediate complication. The period of follow-up ranged between 2 weeks and 3 years with a mean of 10.2 months. There was sustained improvement in urine stream, reduction in the mean creatinine concentration and incidence of UTI during follow-up. However, patients with significantly impaired renal function had a poorer outcome. Many patients with PUV presented late within the reviewed period. Valve ablation provided relief of obstruction in most of the cases. There is a need to

Application of artificial intelligence to motor operated valve testing

International Nuclear Information System (INIS)

Bogard, T.; Bednar, F.; Matty, T.; Kent, R.

1989-01-01

Improper valve maintenance can be a significant roadblock to successful power plant operation. There have been events during which motor operated valves failed on demand due to improper switch settings. For nuclear electric generating stations, these events have led to regulatory requirements such as NRC Bulletin 85-03 and NRC Bulletin 89-10 Safety Related Motor Operated Valve Testing and Surveillance which imposes strict testing and programmatic requirements on motor operated valves (MOV). Part of the requirements include performing diagnostic testing to verify stem thrust loads and switch settings. Diagnostic equipment must be non-intrusive, minimize valve disassembly, and reduce plant refueling critical path time for testing. In this paper an on-line diagnostic system using sensors to measure stem forces, motor current, and valve position, and a portable system employing these same sensor inputs in addition to torque, limit and torque bypass switch inputs is described. Sophisticated graphic software is employed to display data or trace information. A rule based artificial intelligence (AI) system is used to analyze sensor outputs. Objectives for valve diagnostics, sample AI rules, results of actual field testing, and system software/hardware architecture are presented

Flow oscillations on the steam control valve in the middle opening condition. Clarification of the effects of valve body and valve seat by steam experiments

International Nuclear Information System (INIS)

Morita, Ryo; Inada, Fumio

2007-01-01

A steam control valve might cause vibrations of piping when the valve opening is in a middle condition. For rationalization of maintenance and management of the plant, the valve should be improved, but it is difficult to understand flow characteristics in detail by experiment because flow around the valve is complex 3D structure and becomes supersonic (M>1). Therefore, it is necessary to clarify the cause of the vibrations and to develop the countermeasures by CFD (Computational Fluid Dynamics) technology. In previous researches, we clarified a mechanism of the pressure fluctuations in the middle opening condition and suggested the new valve shape (named 'Extended Valve') that can suppress the pressure fluctuations by air experiments and CFD calculations. Then, we also conducted steam experiments and CFD calculations to understand the differences between air and the steam, and found that the pressure fluctuations in the middle opening condition also occurred in the steam tests and the differences between the air and steam were not remarkable. In this report, to clarify the effects of valve and valve seat shape in steam flow condition, we conduct the steam experiments with various valve and seat shape. As a result, we find the change of the valve seat can decrease the amplitude of pressure fluctuations, but can not quite suppress the pressure fluctuations in the middle opening condition. Then, we apply the 'Extended Valve' to clarify the valve shape effect, and find that the extended valve suppresses the pressure fluctuations in the middle opening condition completely and decreases the pressure amplitude drastically. (author)

Reducing Dysfunctional Beliefs about Sleep Does Not Significantly Improve Insomnia in Cognitive Behavioral Therapy

OpenAIRE

Okajima, Isa; Nakajima, Shun; Ochi, Moeko; Inoue, Yuichi

2014-01-01

The present study examined to examine whether improvement of insomnia is mediated by a reduction in sleep-related dysfunctional beliefs through cognitive behavioral therapy for insomnia. In total, 64 patients with chronic insomnia received cognitive behavioral therapy for insomnia consisting of 6 biweekly individual treatment sessions of 50 minutes in length. Participants were asked to complete the Athens Insomnia Scale and the Dysfunctional Beliefs and Attitudes about Sleep scale both at the...

Valve-sparing aortic root reconstruction in children, teenagers, and young adults.

Science.gov (United States)

Tweddell, James S; Earing, Michael G; Bartz, Peter J; Dunham-Ingles, Jennifer L; Woods, Ronald K; Mitchell, Michael E

2012-08-01

We reviewed our experience with valve-sparing aortic root reconstruction (VSARR) using the sinus of Valsalva graft in children, teenagers, and young adults with connective tissue disorders. Results of a single-center experience with VSARR in children, teenagers, and young adults were retrospectively analyzed. End points were death, freedom from reintervention, and freedom from valve dysfunction. Between 2003 and 2010, 16 patients (Marfan, 9; Loeys Dietz syndrome, 6; conotruncal, 1) underwent VSARR. The mean age was 20±7.4 (range, 9 to 36 years). Indications for VSAAR were aortic root enlargement in 14 (sinus of Valsalva Z-score, 6.2±2) and aortic dissection in 2. Additional procedures included replacement of the ascending aorta in 7, with additional replacement of the aortic arch in 2. No early or late deaths occurred. One patient required a pacemaker. One patient with Loeys-Dietz syndrome required reoperation for aneurysmal dilatation of the coronary buttons. Two patients underwent replacement of the thoracoabdominal aorta for chronic dissection. Follow-up by echocardiography or magnetic resonance imaging at a mean of 33±29 months showed more than mild aortic regurgitation in 2 patients. Both patients with moderate aortic insufficiency also had a bicuspid aortic valve. VSARR using the sinus of Valsalva graft is a reproducible technique that achieves acceptable early and intermediate results. It is suitable for children, teenagers, and young adults. Anticoagulation is avoided. The procedure is appropriate for emergency operations but should be used with caution in patients with a bicuspid aortic valve. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

The importance of echocardiography in transcatheter aortic valve implantation.

Science.gov (United States)

Bilen, Emine; Sari, Cenk; Durmaz, Tahir; Keleş, Telat; Bayram, Nihal A; Akçay, Murat; Ayhan, Hüseyin M; Bozkurt, Engin

2014-01-01

Valvular heart diseases cause serious health problems in Turkey as well as in Western countries. According to a study conducted in Turkey, aortic stenosis (AS) is second after mitral valve disease among all valvular heart diseases. AS is frequently observed in elderly patients who have several cardiovascular risk factors and comorbidities. In symptomatic severe AS, surgical aortic valve replacement (AVR) is a definitive treatment. However, in elderly patients with left ventricular dysfunction and comorbidities, the risk of operative morbidity and mortality increases and outweighs the gain obtained from AVR surgery. As a result, almost one-third of the patients with serious AS are considered ineligible for surgery. Transcatheter aortic valve implantation (TAVI) is an effective treatment in patients with symptomatic severe AS who have high risk for conventional surgery. Since being performed for the first time in 2002, with a procedure success rate reported as 95% and a mortality rate of 5%, TAVI has become a promising method. Assessment of vascular anatomy, aortic annular diameter, and left ventricular function may be useful for the appropriate selection of patients and may reduce the risk of complications. Cardiac imaging methods including 2D and 3D echocardiography and multidetector computed tomography are critical during the evaluation of suitable patients for TAVI as well as during and after the procedure. In this review, we describe the role of echocardiography methods in clinical practice for TAVI procedure in its entirety, i.e. from patient selection to guidance during the procedure, and subsequent monitoring. © 2013, Wiley Periodicals, Inc.

Modal-Based Design Improvement of a Butterfly Valve Disc

Directory of Open Access Journals (Sweden)

Marius Draghiciu

2017-11-01

Full Text Available The dynamic behaviour control of a butterfly valve is important because, when one of the valve disc natural frequency is close to the frequency of vortex shedding, which appears when the valve is fully open or partially closed, resonance may appear and vibration with significant amplitudes is generated. This paper presents an example by how the design of a butterfly valve disc can be improved by using a modal analysis performed by means of the finite element method. For this purpose, the research reveals the way in which the natural frequencies of the disc can be modified by applying stiffening ribs or changing the dimensions, respective the position of these ribs.

A Genomics-Based Model for Prediction of Severe Bioprosthetic Mitral Valve Calcification.

Science.gov (United States)

Ponasenko, Anastasia V; Khutornaya, Maria V; Kutikhin, Anton G; Rutkovskaya, Natalia V; Tsepokina, Anna V; Kondyukova, Natalia V; Yuzhalin, Arseniy E; Barbarash, Leonid S

2016-08-31

Severe bioprosthetic mitral valve calcification is a significant problem in cardiovascular surgery. Unfortunately, clinical markers did not demonstrate efficacy in prediction of severe bioprosthetic mitral valve calcification. Here, we examined whether a genomics-based approach is efficient in predicting the risk of severe bioprosthetic mitral valve calcification. A total of 124 consecutive Russian patients who underwent mitral valve replacement surgery were recruited. We investigated the associations of the inherited variation in innate immunity, lipid metabolism and calcium metabolism genes with severe bioprosthetic mitral valve calcification. Genotyping was conducted utilizing the TaqMan assay. Eight gene polymorphisms were significantly associated with severe bioprosthetic mitral valve calcification and were therefore included into stepwise logistic regression which identified male gender, the T/T genotype of the rs3775073 polymorphism within the TLR6 gene, the C/T genotype of the rs2229238 polymorphism within the IL6R gene, and the A/A genotype of the rs10455872 polymorphism within the LPA gene as independent predictors of severe bioprosthetic mitral valve calcification. The developed genomics-based model had fair predictive value with area under the receiver operating characteristic (ROC) curve of 0.73. In conclusion, our genomics-based approach is efficient for the prediction of severe bioprosthetic mitral valve calcification.

Transcatheter aortic-valve replacement with a self-expanding prosthesis.

Science.gov (United States)

Adams, David H; Popma, Jeffrey J; Reardon, Michael J; Yakubov, Steven J; Coselli, Joseph S; Deeb, G Michael; Gleason, Thomas G; Buchbinder, Maurice; Hermiller, James; Kleiman, Neal S; Chetcuti, Stan; Heiser, John; Merhi, William; Zorn, George; Tadros, Peter; Robinson, Newell; Petrossian, George; Hughes, G Chad; Harrison, J Kevin; Conte, John; Maini, Brijeshwar; Mumtaz, Mubashir; Chenoweth, Sharla; Oh, Jae K

2014-05-08

We compared transcatheter aortic-valve replacement (TAVR), using a self-expanding transcatheter aortic-valve bioprosthesis, with surgical aortic-valve replacement in patients with severe aortic stenosis and an increased risk of death during surgery. We recruited patients with severe aortic stenosis who were at increased surgical risk as determined by the heart team at each study center. Risk assessment included the Society of Thoracic Surgeons Predictor Risk of Mortality estimate and consideration of other key risk factors. Eligible patients were randomly assigned in a 1:1 ratio to TAVR with the self-expanding transcatheter valve (TAVR group) or to surgical aortic-valve replacement (surgical group). The primary end point was the rate of death from any cause at 1 year, evaluated with the use of both noninferiority and superiority testing. A total of 795 patients underwent randomization at 45 centers in the United States. In the as-treated analysis, the rate of death from any cause at 1 year was significantly lower in the TAVR group than in the surgical group (14.2% vs. 19.1%), with an absolute reduction in risk of 4.9 percentage points (upper boundary of the 95% confidence interval, -0.4; P<0.001 for noninferiority; P = 0.04 for superiority). The results were similar in the intention-to-treat analysis. In a hierarchical testing procedure, TAVR was noninferior with respect to echocardiographic indexes of valve stenosis, functional status, and quality of life. Exploratory analyses suggested a reduction in the rate of major adverse cardiovascular and cerebrovascular events and no increase in the risk of stroke. In patients with severe aortic stenosis who are at increased surgical risk, TAVR with a self-expanding transcatheter aortic-valve bioprosthesis was associated with a significantly higher rate of survival at 1 year than surgical aortic-valve replacement. (Funded by Medtronic; U.S. CoreValve High Risk Study ClinicalTrials.gov number, NCT01240902.).

Diastolic dysfunction characterizes cirrhotic cardiomyopathy

Directory of Open Access Journals (Sweden)

Piyush O. Somani

2014-11-01

Conclusions: Present study shows that although diastolic dysfunction is a frequent event in cirrhosis, it is usually of mild degree and does not correlate with severity of liver dysfunction. There are no significant differences in echocardiographic parameters between alcoholic and non-alcoholic cirrhosis. HRS is not correlated to diastolic dysfunction in cirrhotic patients. There is no difference in survival at one year between patients with or without diastolic dysfunction. Diastolic dysfunction in cirrhosis is unrelated to circulatory dysfunction, ascites and HRS.

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

International Nuclear Information System (INIS)

Rho, Hyung Joon; Lee, Jee Keun; Choi, Hee Joo

2008-01-01

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

Door valve for fuel handling path

International Nuclear Information System (INIS)

Makishima, Katsuhiko.

1969-01-01

A door valve is provided which seals cover gas from a liquid metal cooled reactor without leakage therefrom. A threaded shaft is screwed into a heavy box press which is packed with lead. The shaft is adapted to be rotated by an electric motor or a manually operated wheel which is disposed outside of the door valve. A valve plate is suspended from the box press by four guide wheels mounted thereon. The guide wheels are fitted into inclined guide grooves formed at the valve plate and into grooved formed in the inner wall of a valve casing. A locking ball is provided at each side of the valve plate. In operation the shaft rotates and travels to permit the box press and the valve plate to move into the door valve casing, thus releasing the locking balls. The valve plate does not contact the bottom of the casing. When the box press reaches the home position, the valve plate is carried on the valve opening, and the box press presses the valve plate to increase the tightness. The valve plate does not suffer wear as it does not slide over other parts. (Yamaguchi, T.)

Characterization of a bioprosthetic bicuspid venous valve hemodynamics: implications for mechanism of valve dynamics.

Science.gov (United States)

Tien, W-H; Chen, H Y; Berwick, Z C; Krieger, J; Chambers, S; Dabiri, D; Kassab, G S

2014-10-01

Chronic venous insufficiency (CVI) of the lower extremities is a common clinical problem. Although bioprosthetic valves have been proposed to treat severe reflux, clinical success has been limited due to thrombosis and neointima overgrowth of the leaflets that is, in part, related to the hemodynamics of the valve. A bioprosthetic valve that mimics native valve hemodynamics is essential. A computational model of the prosthetic valve based on realistic geometry and mechanical properties was developed to simulate the interaction of valve structure (fluid-structure interaction, FSI) with the surrounding flow. The simulation results were validated by experiments of a bioprosthetic bicuspid venous valve using particle image velocimetry (PIV) with high spatial and temporal resolution in a pulse duplicator (PD). Flow velocity fields surrounding the valve leaflets were calculated from PIV measurements and comparisons to the FSI simulation results were made. Both the spatial and temporal results of the simulations and experiments were in agreement. The FSI prediction of the transition point from equilibrium phase to valve-closing phase had a 7% delay compared to the PD measurements, while the PIV measurements matched the PD exactly. FSI predictions of reversed flow were within 10% compared to PD measurements. Stagnation or stasis regions were observed in both simulations and experiments. The pressure differential across the valve and associated forces on the leaflets from simulations showed the valve mechanism to be pressure driven. The flow velocity simulations were highly consistent with the experimental results. The FSI simulation and force analysis showed that the valve closure mechanism is pressure driven under the test conditions. FSI simulation and PIV measurements demonstrated that the flow behind the leaflet was mostly stagnant and a potential source for thrombosis. The validated FSI simulations should enable future valve design optimizations that are needed for

Expression of GSK-3β in renal allograft tissue and its significance in pathogenesis of chronic allograft dysfunction

Directory of Open Access Journals (Sweden)

Yan Qiang

2012-01-01

Full Text Available Abstract Objective To explore the expression of Glycogen synthase kinase 3 beta (GSK-3β in renal allograft tissue and its significance in the pathogenesis of chronic allograft dysfunction. Methods Renal allograft biopsy was performed in all of the renal allograft recipients with proteinuria or increased serum creatinine level who came into our hospital from January 2007 to December 2009. Among them 28 cases was diagnosed as chronic allograft dysfunction based on pahtological observation, including 21 males with a mean age of 45 ± 10 years old and 7 females with a mean age of 42 ± 9 years old. The time from kidney transplantation to biopsy were 1-9 (3.5 years. Their serum creatinine level were 206 ± 122 umol/L. Immunohistochemical assay and computer-assisted genuine color image analysis system (imagepro-plus 6.0 were used to detect the expression of GSK-3β in the renal allografts of 28 cases of recipients with chronic allograft dysfunction. Mean area and mean integrated optical density of GSK-3β expression were calculated. The relationship between expression level of GSK-3β and either the grade of inflammatory cell infiltration or interstitial fibrosis/tubular atrophy in renal allograft was analyzed. Five specimens of healthy renal tissue were used as controls. Results The expression level of the GSK-3β was significantly increased in the renal allograft tissue of recipients with chronic allograft dysfunction, compared to normal renal tissues, and GSK-3β expression became stronger along with the increasing of the grade of either inflammatory cell infiltration or interstitial fibrosis/tubular atrophy in renal allograft tissue. Conclusion There might be a positive correlation between either inflammatory cell infiltration or interstitial fibrosis/tubular atrophy and high GSK-3β expression in renal allograft tissue. Virtual slides The virtual slide(s for this article can be found here: http

Left ventricular mass regression is independent of gradient drop and effective orifice area after aortic valve replacement with a porcine bioprosthesis.

Science.gov (United States)

Sádaba, Justo Rafael; Herregods, Marie-Christine; Bogaert, Jan; Harringer, Wolfgang; Gerosa, Gino

2012-11-01

The question of whether left ventricular mass (LVM) regression following aortic valve replacement (AVR) is affected by the prosthesis indexed effective orifice area (IEOA) and transprosthetic gradient has not been fully elucidated. Data from a prospective, core-laboratory-reviewed echocardiography and magnetic resonance imaging (MRI) study was used to determine if the degree of LVM regression following AVR with two types of porcine bioprosthesis in patients suffering from predominant aortic valve stenosis (AS) was related to the prosthesis IEOA and transprosthetic gradient. Over a two-year period, 149 patients enrolled at eight centers received either an Epic or an Epic Supra aortic bioprosthesis (St. Jude Medical, MN, USA). Preoperative valve dysfunction was pure AS in 54 patients (36%) and mixed valve disease (primarily stenosis) in 95 patients (64%). LVM was determined preoperatively and at six months postoperatively, using MRI. The prosthesis IEOA and transprosthetic gradient were calculated at six months by means of echocardiography. Data were available for 111 patients at both enrolment and six months postoperatively. The LVM at enrolment and at follow up was 154.96 +/- 42.50 g and 114.83 +/- 29.20 g, respectively (p regression methods, showed LVM regression to be independent of the mean systolic pressure gradient, peak systolic pressure and prosthesis IEOA at six months (p = 0.53, 0.43, and 0.15, respectively). At six months after AVR with a porcine bioprosthesis to treat AS, there was a significant LVM regression that was independent of the prosthesis IEOA and the mean systolic pressure gradient and peak systolic pressure.

Cryogenic Cam Butterfly Valve

Science.gov (United States)

McCormack, Kenneth J. (Inventor)

2016-01-01

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

Unicuspid aortic valve disease: a magnetic resonance imaging study

Energy Technology Data Exchange (ETDEWEB)

Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A. [Klinik und Poliklinik fuer Innere Medizin II, Universitaetsklinikum Regensburg (Germany); Djavidani, B.; Poschenrieder, F.; Feuerbach, S. [Inst. fuer Roentgendiagnostik, Universitaetsklinikum Regensburg (Germany); Schmid, C.; Kobuch, R. [Klinik und Poliklinik fuer Herz-, Thorax- und herznahe Gefaesschirurgie, Universitaetsklinikum Regensburg (Germany)

2008-11-15

Purpose: congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI). Materials and methods/results: MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 {+-} 4.7 cm{sup 2} vs. 8.7 {+-} 2.3 cm{sup 2}, p < 0.01 and 4.6 {+-} 0.7 cm vs. 3.6 {+-} 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 {+-} 0.6 cm vs. 2.3 {+-} 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 {+-} 0.5 cm vs. 2.6 {+-} 0.3 cm, p < 0.05). (orig.)

Small valve area index: its influence on early mortality after mitral valve replacement

NARCIS (Netherlands)

Yazdanbakhsh, A. P.; van den Brink, R. B.; Dekker, Egbert; de Mol, B. A.

2000-01-01

OBJECTIVE: To test the hypothesis that mitral valve prosthesis-patient mismatch increases postoperative mortality. METHODS AND RESULTS: The effect of mitral valve prosthesis-patient mismatch on survival in a cohort of consecutive patients after mitral valve replacement with a mechanical prosthesis

Functional property of the cardiac valve prosthesis evaluated in vivo by cine-radiography

International Nuclear Information System (INIS)

Murakoshi, Sadaaki

1986-01-01

Functional property of the convexo-concave Bjoerk-Shiley cardiac valve prosthesis implanted in the mitral position of 21 patients was investigated by integrated cine-radiography repeated for a long term after operation. The maximum opening angle of the tilting disc was 58 ± 2 deg, and was not affected by atrial fibrillation nor by tachycardia up to 160 bpm. There was no change in the maximum opening angle of the disc observed during follow-up period. Good correlation between shortning of the disc opening time and increase in pulse rate suggests excellent adaptation of this prosthesis for tachycardia induced by exercise or electric pacing. However, atrial fibrillation causes time delay in disc closure immediately after prolonged R-R interval. Disc rotation alleviating disc wear was observed in all the patients whether it moves slow or quick. Dysfunction of the disc opening can be readily determined not only by measuring the maximum disc opening angle, but also by observing the characteristic movement indicated in this study. It is concluded from these results that clinical apprication for the convexo-concave Bjoerk-Shiley valve prosthesis is appropriate and cine-radiography is an useful non-invasive examination of cardiac valve prosthesis for long follow-up period. (author)

Functional property of the cardiac valve prosthesis evaluated in vivo by cine-radiography

Energy Technology Data Exchange (ETDEWEB)

Murakoshi, Sadaaki

1986-07-01

Functional property of the convexo-concave Bjoerk-Shiley cardiac valve prosthesis implanted in the mitral position of 21 patients was investigated by integrated cine-radiography repeated for a long term after operation. The maximum opening angle of the tilting disc was 58 +- 2 deg, and was not affected by atrial fibrillation nor by tachycardia up to 160 bpm. There was no change in the maximum opening angle of the disc observed during follow-up period. Good correlation between shortning of the disc opening time and increase in pulse rate suggests excellent adaptation of this prosthesis for tachycardia induced by exercise or electric pacing. However, atrial fibrillation causes time delay in disc closure immediately after prolonged R-R interval. Disc rotation alleviating disc wear was observed in all the patients whether it moves slow or quick. Dysfunction of the disc opening can be readily determined not only by measuring the maximum disc opening angle, but also by observing the characteristic movement indicated in this study. It is concluded from these results that clinical apprication for the convexo-concave Bjoerk-Shiley valve prosthesis is appropriate and cine-radiography is an useful non-invasive examination of cardiac valve prosthesis for long follow-up period.

Mitral valve prolapse in Zaria: clinical and echocardiographic features

African Journals Online (AJOL)

Background: Mitral valve prolapse (MVP) symptomatology and presentation are said to be of questionable significance. Method: A prospective study of 10 patients with mitral valve prolapse seen at Ahmadu Bello University Hospital in two years. Results: There were six females and four males. Their ages ranged from 5 to ...

Overweight causes left ventricular diastolic asynchrony and diastolic dysfunction: a study based on speckle tracking echocardiography in healthy subjects.

Science.gov (United States)

Nakabachi, Masahiro; Mikami, Taisei; Okada, Kazunori; Onozuka, Hisao; Kaga, Sanae; Inoue, Mamiko; Yokoyama, Shinobu; Nishida, Mutsumi; Shimizu, Chikara; Matsuno, Kazuhiko; Iwano, Hiroyuki; Yamada, Satoshi; Tsutsui, Hiroyuki

2012-09-01

Left ventricular (LV) diastolic dysfunction is often observed in healthy subjects and can be a cause of heart failure with preserved ejection fraction (EF). We aimed to investigate the role of LV diastolic asynchrony as a cause of diastolic dysfunction in healthy subjects. In 40 healthy subjects, two-dimensional speckle tracking imaging (2DSTI) was performed to measure the peak early diastolic longitudinal strain rates (Esr) of the apical, mid-ventricular, and basal segments of the septum and posterior wall. A mean value of the Esr of the 6 segments (mEsr) was calculated. The time from aortic valve closure to the Esr was measured for each segment, and the standard deviation (SDTEsr) was calculated. The peak global early diastolic strain rate (gEsr) was measured with a region of interest (ROI) on the whole LV myocardium. LV flow propagation velocity (FPV) was measured using conventional Doppler techniques. SDTEsr was not correlated with age, but was significantly correlated with body mass index (BMI) (r = 0.41, p < 0.01). Although no significant correlation was observed between mEsr and FPV, gEsr and SDTEsr significantly correlated with FPV (r = 0.41, p < 0.01; r = -0.54, p < 0.001). As a result of the multiple regression analysis, SDTEsr was the single determinant of FPV. Diastolic asynchrony, associated with overweight but not with aging, may contribute to diastolic dysfunction in healthy subjects.

Predictors of transient left ventricular dysfunction following transcatheter patent ductus arteriosus closure in pediatric age.

Science.gov (United States)

Agha, Hala Mounir; Hamza, Hala S; Kotby, Alyaa; Ganzoury, Mona E L; Soliman, Nanies

2017-10-01

To evaluate the left ventricular function before and after transcatheter percutaneous patent ductus arteriosus (PDA) closure, and to identify the predictors of myocardial dysfunction post-PDA closure if present. Transcatheter PDA closure; conventional, Doppler, and tissue Doppler imaging; and speckle tracking echocardiography. To determine the feasibility and reliability of tissue Doppler and myocardial deformation imaging for evaluating myocardial function in children undergoing transcatheter PDA closure. Forty-two children diagnosed with hemodynamically significant PDA underwent percutaneous PDA closure. Conventional, Doppler, and tissue Doppler imaging, and speckle-derived strain rate echocardiography were performed at preclosure and at 48 hours, 1 month, and 6 months postclosure. Tissue Doppler velocities of the lateral and septal mitral valve annuli were obtained. Global and regional longitudinal peak systolic strain values were determined using two-dimensional speckle tracking echocardiography. The median age of the patients was 2 years and body weight was 15 kg, with the mean PDA diameter of 3.11 ± 0.99 mm. M-mode measurements (left ventricular end diastolic diameter, left atrium diameter to aortic annulus ratio, ejection fraction, and shortening fraction) reduced significantly early after PDA closure ( p  closure causes a significant decrease in left ventricular performance early after PDA closure, which recovers completely within 1 month. Preclosure global longitudinal strain can be a predictor of postclosure myocardial dysfunction.

Midterm Results of Aortic Valve Replacement with Cryopreserved Homografts

Directory of Open Access Journals (Sweden)

Emre Özker

2012-06-01

Full Text Available Objective: The aim of this study was to analyze the midterm clinical results of aortic valve replacement with cryopreserved homografts.Materials and Methods: Aortic valve replacement was performed in 40 patients with cryopreserved homograft. The indications were aortic valve endocarditis in 20 patients (50%, truncus arteriosus in 6 patients (15%, and re-stenosis or regurtitation after aortic valve reconstruction in 14 (35% patients. The valve sizes ranged from 10 to 27mm. A full root replacement technique was used for homograft replacement in all patients.Results: The 30-day postoperative mortality rate was 12.5% (5 patients. There were four late deaths. Only one of them was related to cardiac events. Overall mortality was 22.5%. Thirty-three patients were followed up for 67±26 months. Two patients needed reoperation due to aortic aneurysm caused by endocarditis. The mean transvalvular gradient significantly decreased after valve replacement (p<0.003. The last follow up showed that the 27 (82% patients had a normal left ventricular function.Conclusion: Cryopreserved homografts are safe alternatives to mechanical valves that can be used when there are proper indications. Although it has a high perioperative mortality rate, cryopreserved homograft implantation is an alternative for valve replacement, particularly in younger patients and for complex surgical problems such as endocarditis that must be minimalized.

The management of vesicoureteral reflux in the setting of posterior urethral valve with emphasis on bladder function and renal outcome: a single center cohort study.

Science.gov (United States)

Tourchi, Ali; Kajbafzadeh, Abdol-Mohammad; Aryan, Zahra; Ebadi, Maryam

2014-01-01

To represent our experience in the management of posterior urethral valves and concomitant vesicoureteral reflux (VUR). A total of 326 children with posterior urethral valve who had underwent valve ablation/bladder neck incision were studied, and those who had persistent VUR and were categorized under 3 main groups were followed up. Group 1 (n = 71) received prophylactic antibiotic, group 2 (n = 50) underwent Deflux injection (2a) (n = 28): Deflux injection alone, group 2b (n = 22) Deflux with concomitant autologous blood injection (HABIT), and group 3 (n = 19) underwent ureteroneocystostomy before referral and was followed up conservatively. VUR resolution, incidence of urinary tract infections (UTI), and bladder function were assessed. Mean duration of follow-up was 3.8 years; VUR resolution occurred in 66.1%, 86.0%, and 94.0% of groups 1-3, respectively (P = .013). Resolution rate in group 2b was significantly higher than group 2a (90.9% vs 78.5%). Patients in group 2 experienced a longer UTI-free period compared with others (P <.05). Urodynamic studies demonstrated significant decrease in maximum voiding detrusor pressure and detrusor overactivity in all groups (P <.001). Children in group 3 ended up with lower compliance compared with others (P <.001). After toilet training, only 2.8%, 21.4%, 13.6%, and 27% children were diagnosed with lower urinary tract dysfunction in groups 1-3, respectively (P = .027). Myogenic failure developed only in 3 boys in group 3. Ablation/bladder neck incision leads to significant improvement in VUR status in part because of improvement in bladder function. After successful valve removal, conservative therapy can be regarded as the mainstay of reflux treatment, whereas HABIT is recommended for high grade VUR associated with febrile UTI or deterioration in renal function. Copyright © 2014 Elsevier Inc. All rights reserved.

Low noise control valve

International Nuclear Information System (INIS)

Christie, R.S.

1975-01-01

Noise is one of the problems associated with the use of any type of control valve in systems involving the flow of fluids. The advent of OSHA standards has prompted control valve manufacturers to design valves with special trim to lower the sound pressure level to meet these standards. However, these levels are in some cases too high, particularly when a valve must be located in or near an area where people are working at tasks requiring a high degree of concentration. Such locations are found around and near research devices and in laboratory-office areas. This paper describes a type of fluid control device presently being used at PPL as a bypass control valve in deionized water systems and designed to reduce sound pressure levels considerably below OSHA standards. Details of the design and construction of this constant pressure drop variable flow control valve are contained in the text and are shown in photographs and drawings. Test data taken are included

Myocardial hypertrophy and intracardial hemodynamics in children with bicuspid aortic valve

Directory of Open Access Journals (Sweden)

А. V. Kamenshchyk

2017-08-01

Full Text Available Bicuspid aortic valve is one of the most common congenital heart diseases with low manifestation in childhood and severe consequences in adults that determines the importance in early diagnostics of myocardial changes in this anomaly. According to the literature the polymorphisms in the genes of NFATC family could result both in impaired embriogenetic valves formation and development of postnatal myocardial hypertrophy. The aim of the study was to detect the early changes of intracardial hemodynamics at aortic valve in children with bicuspid aortic valve (BAV and establish their interrelations to the signs of myocardial hypertrophy in these children. Materials and methods: Dopplerograhphic study of basic intracardiac hemodynamics parameters in 38 children with BAV and in 28 children of control group was conducted. The results were processed statistically by Student’s t-test, correlation analysis and multiple regression. Results: In the result of study the moderate concentric left ventricle myocardial hypertrophy development was detected in 62 % of children with BAV which is accompanying to significant increasing of blood flow velocity and pressure gradient at aortic valve. There were not established significant correlations between the parameters of hemodynamics at valve and left ventricle’s posterior wall depth and septum depth whereas the highest inputs of these values were obtained in the left ventricle systolic dimension and volume and less in the hypertrophic signs. Conclusions: In children with BAV the moderate concentric myocardial hypertrophy with significant changes of intracardial hemodynamics at aortic valve takes place with the highest inputs in left ventricle volumetric values The obtained data serves as a substantiation for the treatment and prevention of it further development. bicuspid aortic valve; children; heart hypertrophy; dopplerechocardiography; hemodynamics; regression analysis

Idiopathic mitral valve prolapse with tricuspid, aortic and pulmonary valve involvement: An autopsy case report

Directory of Open Access Journals (Sweden)

Heena M Desai

2015-01-01

Full Text Available Mitral valve prolapse (MVP is usually asymptomatic, but can be associated with complications such as infective endocarditis, mitral regurgitation, thromboembolism and sudden cardiac death. It has been very rarely reported to occur in association with other valvular involvement. A 55-year-old male patient was brought dead and at autopsy the mitral valve orifice was stenotic and the leaflets were enlarged, myxoid and bulging suggestive of MVP and chordae tendinae were thickened, stretched and elongated. Similar changes were seen in the tricuspid valve. The pulmonary and aortic valves also showed myxomatous degeneration of their cusps. Myxomatous degeneration is the most common cause of MVP and it can be associated with involvement of the other valves. Concomitant involvement of the aortic valve has been reported, however it is very rare and simultaneous involvement of the pulmonary valve has not been reported in the literature so far. We report a case of MVP associated with myxomatous degeneration of the tricuspid, pulmonary and aortic valves.

Valve for closing a steam line

International Nuclear Information System (INIS)

Meyer, W.; Potrykus, G.

1976-01-01

Instead of several control elements, the quick-closing valve, especially in the main-steam line between steam generator and turbine of a power station has the valve cone itself as the only movable part, acting with its inner surface as a piston within a second cylinder space. The valve shaft is at the same time a piston rod with a stepped piston at the upper end. This piston is loaded in a cylinder at the upspace below the valve cover on one hand by a spring, on the other hand by its own medium. Two non-return valves, one of it in a bore of the valve cone, connect the first-mentioned cylinder space with the steam-loaded inlet resp. outlet side of the valve. For controlling the valve, a magnet valve is sufficient. By automatic control of the valve cone coupled with several pistons several control lines can be omitted. There are also no pressurized control lines outside the valve which could be damaged by exterior influences. (ERA) [de

Patients With Fibromyalgia Have Significant Autonomic Symptoms But Modest Autonomic Dysfunction.

Science.gov (United States)

Vincent, Ann; Whipple, Mary O; Low, Phillip A; Joyner, Michael; Hoskin, Tanya L

2016-05-01

Research suggests that disordered autonomic function may be one contributor to deconditioning reported in fibromyalgia; however, no study to date has assessed these variables simultaneously with comprehensive measures. To characterize physical fitness and autonomic function with the use of clinically validated measures and subjective questionnaires between patients with fibromyalgia and healthy controls. Cross-sectional, observational, controlled study. Community sample of patients with fibromyalgia and healthy controls. Thirty patients with fibromyalgia and 30 pain and fatigue-free controls. Participants completed a battery of self-report questionnaires and physiological measures, including clinically validated measures of physical fitness and autonomic function. Six-Minute Walk Test total distance, maximal oxygen consumption as assessed by cardiopulmonary exercise testing, total steps using activity monitor, Composite Autonomic Scoring Scale as assessed by Autonomic Reflex Screen, total metabolic equivalents per week using the International Physical Activity Questionnaire, and self-reported autonomic symptoms via the 31-item Composite Autonomic Symptom Score questionnaire. Autonomic function, as assessed by self-report, was significantly different between patients and controls (P physical activity was not significantly different between patients and controls (P = .99), but levels of moderate and vigorous physical activity as measured by actigraphy were significantly lower in patients (P = .012 and P = .047, respectively). Exercise capacity (6-Minute Walk) was poorer in patients (P = .0006), but there was no significant difference in maximal volume of oxygen consumption (P = .07). Patients with fibromyalgia report more severe symptoms across all domains, including physical activity and autonomic symptoms, compared with controls, but the objective assessments only showed modest differences. Our results suggest that patients with widespread subjective impairment of

Designed pneumatic valve actuators for controlled droplet breakup and generation.

Science.gov (United States)

Choi, Jae-Hoon; Lee, Seung-Kon; Lim, Jong-Min; Yang, Seung-Man; Yi, Gi-Ra

2010-02-21

The dynamic breakup of emulsion droplets was demonstrated in double-layered microfluidic devices equipped with designed pneumatic actuators. Uniform emulsion droplets, produced by shearing at a T-junction, were broken into smaller droplets when they passed downstream through constrictions formed by a pneumatically actuated valve in the upper control layer. The valve-assisted droplet breakup was significantly affected by the shape and layout of the control valves on the emulsion flow channel. Interestingly, by actuating the pneumatic valve immediately above the T-junction, the sizes of the emulsion droplets were controlled precisely in a programmatic manner that produced arrays of uniform emulsion droplets in various sizes and dynamic patterns.

Charging valve of the full hydraulic braking system

Directory of Open Access Journals (Sweden)

Jinshi Chen

2016-03-01

Full Text Available It is known that the full hydraulic braking system has excellent braking performance. As the key component of the full hydraulic braking system, the parameters of the accumulator charging valve have a significant effect on the braking performance. In this article, the key parameters of the charging valve are analyzed through the static theoretical and an Advanced Modeling Environment for performing Simulation of engineering systems (AMESim simulation model of the dual-circuit accumulator charging valve is established based on the real structure parameters first. Second, according to the results of the dynamic simulation, the dynamic characteristics of the charging pressure, the flow rate, and the frequency of the charging valve are studied. The key parameters affecting the serial production are proposed and some technical advices for improving the performance of the full hydraulic system are provided. Finally, the theoretical analysis is validated by the simulation results. The comparison between the simulation results and the experimental results indicates that the simulated AMESim model of the charging valve is accurate and credible with the error rate inside 0.5% compared with the experimental result. Hence, the performance of the charging valve meets the request of the full hydraulic braking system exactly.

A characterization of check valve degradation and failure experience in the nuclear power industry

International Nuclear Information System (INIS)

Casada, D.A.; Todd, M.D.

1993-09-01

Check valve operating problems in recent years have resulted in significant operating transients, increased cost and decreased system availability. As a result, additional attention has beau given to check valves by utilities (resulting in the formation of the Nuclear Industry Check Valve Group), as well as the US Nuclear Regulatory Commission and the American Society of Mechanical Engineers Operation and Maintenance Committee. All these organizations have the fundamental goal of ensuring reliable operation of check valves. A key ingredient to an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. A detailed review of historical failure data, available through the Institute of Nuclear Power Operation's Nuclear Plant Reliability Data System, has been conducted. The focus of the review is on check valve failures that have involved significant degradation of the valve internal parts. A variety of parameters are considered, including size, age, system of service, method of failure discovery, the affected valve parts, attributed causes, and corrective actions

Inhibitory role of Notch1 in calcific aortic valve disease.

Directory of Open Access Journals (Sweden)

Asha Acharya

Full Text Available Aortic valve calcification is the most common form of valvular heart disease, but the mechanisms of calcific aortic valve disease (CAVD are unknown. NOTCH1 mutations are associated with aortic valve malformations and adult-onset calcification in families with inherited disease. The Notch signaling pathway is critical for multiple cell differentiation processes, but its role in the development of CAVD is not well understood. The aim of this study was to investigate the molecular changes that occur with inhibition of Notch signaling in the aortic valve. Notch signaling pathway members are expressed in adult aortic valve cusps, and examination of diseased human aortic valves revealed decreased expression of NOTCH1 in areas of calcium deposition. To identify downstream mediators of Notch1, we examined gene expression changes that occur with chemical inhibition of Notch signaling in rat aortic valve interstitial cells (AVICs. We found significant downregulation of Sox9 along with several cartilage-specific genes that were direct targets of the transcription factor, Sox9. Loss of Sox9 expression has been published to be associated with aortic valve calcification. Utilizing an in vitro porcine aortic valve calcification model system, inhibition of Notch activity resulted in accelerated calcification while stimulation of Notch signaling attenuated the calcific process. Finally, the addition of Sox9 was able to prevent the calcification of porcine AVICs that occurs with Notch inhibition. In conclusion, loss of Notch signaling contributes to aortic valve calcification via a Sox9-dependent mechanism.

A high performance magnetorheological valve with a meandering flow path

International Nuclear Information System (INIS)

Imaduddin, Fitrian; Amri Mazlan, Saiful; Azizi Abdul Rahman, Mohd; Zamzuri, Hairi; Ubaidillah; Ichwan, Burhanuddin

2014-01-01

The huge developments in the field of magnetorheological (MR) fluid-based devices will have a great influence on the future of mechatronic applications due to the ease of interfacing between electronic controls and the mechanical components that they provide. Among various MR fluid-based devices, an MR valve would be particularly significant for the development of other devices, if it could be successfully achieved. One of the most challenging obstacles to MR valve development is the difficulty of achieving device miniaturization while, at the same time, improving the achievable performance. This study demonstrates a novel design for an MR valve, using the meandering flow path approach in order to increase the effective area so that the MR fluid can be regulated within a small-sized valve. The meandering flow path is formed by combining multiple annular, radial and orifice flow channels. In order to analyze the valve performance, a mathematical model of the proposed MR valve is derived and combined with numerical simulation using the finite element method, with the intention of predicting the achievable pressure drop that can be generated by the valve. The predicted MR valve performances are then experimentally evaluated using an oscillation-disturbed bypass hydraulic cylinder. The simulation results show that the proposed MR valve design could yield substantial pressure drop improvement, which is confirmed by the experiment

Door valve for fuel handling path

International Nuclear Information System (INIS)

Makishima, Katsuhiko.

1969-01-01

A door valve is provided which seals cover gas from a liquid metal cooled reactor without leakage therefrom. A threaded shaft is screwed into a heavy box press which is packed with lead. The shaft is adapted to be rotated by an electric motor or a manually operated wheel which is disposed outside of the door valve. From the box press a valve plate is suspended by four linkage bars, one for each corner. Each linkage bar is provided with two wheels which are respectively mounted at the connections with the box press and the valve plate. The wheels are carried on the horizontal grooves formed in a door valve casing. In operation the shaft rotates and travels to permit the box press and the valve plate to move into the door valve casing while the valve plate does not contact the casing. When the box press reaches the home position, the wheels drop into the recesses which are disposed at the ends of the grooves, the valve plate is carried on the valve opening, and the box press presses the valve plate to increase the tightness. The valve plate does not suffer wear as it does not over other parts. (Yamaguchi, T.)

Unicuspid aortic valve disease: a magnetic resonance imaging study

International Nuclear Information System (INIS)

Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A.; Djavidani, B.; Poschenrieder, F.; Feuerbach, S.; Schmid, C.; Kobuch, R.

2008-01-01

Purpose: congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI). Materials and methods/results: MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 ± 4.7 cm 2 vs. 8.7 ± 2.3 cm 2 , p < 0.01 and 4.6 ± 0.7 cm vs. 3.6 ± 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 ± 0.6 cm vs. 2.3 ± 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 ± 0.5 cm vs. 2.6 ± 0.3 cm, p < 0.05). (orig.)

Gate valve performance prediction

International Nuclear Information System (INIS)

Harrison, D.H.; Damerell, P.S.; Wang, J.K.; Kalsi, M.S.; Wolfe, K.J.

1994-01-01

The Electric Power Research Institute is carrying out a program to improve the performance prediction methods for motor-operated valves. As part of this program, an analytical method to predict the stem thrust required to stroke a gate valve has been developed and has been assessed against data from gate valve tests. The method accounts for the loads applied to the disc by fluid flow and for the detailed mechanical interaction of the stem, disc, guides, and seats. To support development of the method, two separate-effects test programs were carried out. One test program determined friction coefficients for contacts between gate valve parts by using material specimens in controlled environments. The other test program investigated the interaction of the stem, disc, guides, and seat using a special fixture with full-sized gate valve parts. The method has been assessed against flow-loop and in-plant test data. These tests include valve sizes from 3 to 18 in. and cover a considerable range of flow, temperature, and differential pressure. Stem thrust predictions for the method bound measured results. In some cases, the bounding predictions are substantially higher than the stem loads required for valve operation, as a result of the bounding nature of the friction coefficients in the method

Mitral Valve Prolapse

Science.gov (United States)

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

Application of ceramics to the sliding seat of valve bridge; Valve bridge yodobu eno ceramics tekiyo

Energy Technology Data Exchange (ETDEWEB)

Matsui, T; Ono, T [Mitsubishi Motors Corp., Tokyo (Japan)

1997-10-01

For use in the valve train, using an OHV (over head valve) configuration. of a 4 valve diesel engine for trucks and buses; we developed a valve bridge, a component of a valve train, with a ceramic head that is made of silicon nitride(Si3N4) in contact with a rocker arm in order to reduce cost and improve wear resistance for further diesel engine emissions regulations. In order to evaluate the effect of this valve bridge, RIG tests and durability tests on actual engines were carried out. 7 figs., 2 tabs.

Strut fracture and disc embolization of a Björk-Shiley mitral valve prosthesis: localization of embolized disc by computerized axial tomography.

Science.gov (United States)

Larrieu, A J; Puglia, E; Allen, P

1982-08-01

The case of a patient who survived strut fracture and embolization of a Björk-Shiley mitral prosthetic disc is presented. Prompt surgical treatment was directly responsible for survival. In addition, computerized axial tomography of the abdomen aided in localizing and retrieving the embolized disc, which was lodged at the origin of the superior mesenteric artery. A review of similar case reports from the literature supports our conclusions that the development of acute heart failure and absent or muffled prosthetic heart sounds in a patient with a Björk-Shiley prosthetic heart valve inserted prior to 1978 should raise the possibility of valve dysfunction and lead to early reoperation.

Relation of mitral valve morphology and motion to mitral regurgitation severity in patients with mitral valve prolapse

Directory of Open Access Journals (Sweden)

Sénéchal Mario

2012-01-01

Full Text Available Abstract Background Mitral valve thickness is used as a criterion to distinguish the classical from the non-classical form of mitral valve prolapse (MVP. Classical form of MVP has been associated with higher risk of mitral regurgitation (MR and concomitant complications. We sought to determine the relation of mitral valve morphology and motion to mitral regurgitation severity in patients with MVP. Methods We prospectively analyzed transthoracic echocardiograms of 38 consecutive patients with MVP and various degrees of MR. In the parasternal long-axis view, leaflets length, diastolic leaflet thickness, prolapsing depth, billowing area and non-coaptation distance between both leaflets were measured. Results Twenty patients (53% and 18 patients (47% were identified as having moderate to severe and mild MR respectively (ERO = 45 ± 27 mm2 vs. 5 ± 7 mm2, p Conclusions In patients with MVP, thick mitral leaflet is not associated with significant MR. Leaflet thickness is probably not as important in risk stratification as previously reported in patients with MVP. Other anatomical and geometrical features of the mitral valve apparatus area appear to be much more closely related to MR severity.

Transcatheter Mitral Valve-in-Ring Implantation

LENUS (Irish Health Repository)

Tanner, RE

2018-05-01

Failed surgical mitral valve repair using an annuloplasty ring has traditionally been treated with surgical valve replacement or repair1. For patients at high risk for repeat open heart surgery, placement of a trans-catheter aortic valve (i.e., TAVI valve) within the mitral ring (i.e., Mitral-Valve-in-Ring, MViR) has emerged as a novel alternative treatment strategy2-5 . We describe our experience of a failed mitral valve repair that was successfully treated with a TAVI valve delivered via the trans-septal approach, and summarise the data relating to this emerging treatment strategy.

Space Vehicle Valve System

Science.gov (United States)

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

2014-01-01

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

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

DEFF Research Database (Denmark)

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

2009-01-01

Transcatheter aortic valve implantation (TAVI) in severe aortic stenosis has proven to be a feasible and effective treatment modality for inoperable patients. Until now, neither aortic regurgitation nor degenerated bioprostheses has been an indication for TAVI. However, this article reports...... a successful valve-in-valve implantation of a CoreValve aortic valve prosthesis through the right subclavian artery in a case of severe aortic regurgitation within a degenerated aortic homograft. The case exemplifies the possibilities of expanding the indications for TAVI, as well as other vascular access...

Cobalt reduction of NSSS valve hardfacings for ALARA

Energy Technology Data Exchange (ETDEWEB)

Kim, Joo Hak; Lee, Sang Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-07-01

This report informs NSSS designer that replacement of materials is one of the major means of ALARA implementation, and describes that NSSS valves with high-cobalt hardfacing are significant contributors to post-shutdown radiation fields caused by activation of cobalt-59 to cobalt-60. Generic procedures for implementing cobalt reduction programs for valves are presented. Discussions are presented of the general and specific design requirements for valve hardfacing in nuclear service. The nuclear safety issues involved with changing valve hardfacing materials are discussed. The common methods used to deposit hardfacing materials are described together with an explanation of the wear measurements. Wear resistance, corrosion resistance, friction coefficient, and mechanical properties of candidate hardfacing alloys are given. World-wide nuclear utility experience with cobalt-free hardfacing alloys is described. The use of low-cobalt or cobalt-free alloys in other nuclear plant components is described. 17 figs., 38 tabs., 18 refs. (Author).

Cobalt reduction of NSSS valve hardfacings for ALARA

International Nuclear Information System (INIS)

Kim, Joo Hak; Lee, Sang Sub

1994-07-01

This report informs NSSS designer that replacement of materials is one of the major means of ALARA implementation, and describes that NSSS valves with high-cobalt hardfacing are significant contributors to post-shutdown radiation fields caused by activation of cobalt-59 to cobalt-60. Generic procedures for implementing cobalt reduction programs for valves are presented. Discussions are presented of the general and specific design requirements for valve hardfacing in nuclear service. The nuclear safety issues involved with changing valve hardfacing materials are discussed. The common methods used to deposit hardfacing materials are described together with an explanation of the wear measurements. Wear resistance, corrosion resistance, friction coefficient, and mechanical properties of candidate hardfacing alloys are given. World-wide nuclear utility experience with cobalt-free hardfacing alloys is described. The use of low-cobalt or cobalt-free alloys in other nuclear plant components is described. 17 figs., 38 tabs., 18 refs. (Author)

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

Science.gov (United States)

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

Thermally induced pressure locking of gate valves: A survey of valve bonnet pressurization rates

International Nuclear Information System (INIS)

Ezekoye, L.I.; Moore, W.E.

1996-01-01

Closed, water filled gate valves run the risk of becoming pressurized due to heat input from the environment or from adjacent connected piping. Thermal pressurization of gate valve bonnets may lead to the valves failing to open on demand and can even induce structural failure of valves. This paper presents an analytical prediction of the pressurization rate of a closed pressure vessel subject to uniform heating which may be considered as an upper bound to the pressurization rate that may occur in the field. Then actual valve experiences described in the literature are reviewed to determine the expected pressurization rate in existing hardware designs. A statistical approach is applied to reconcile the differing pressurization rates reported in the literature and determine a rate that can be applied in valve evaluations. The limitations of the reconciled rate are discussed

Repaired tetralogy of Fallot: the roles of cardiovascular magnetic resonance in evaluating pathophysiology and for pulmonary valve replacement decision support

Science.gov (United States)

2011-01-01

Surgical management of tetralogy of Fallot (TOF) results in anatomic and functional abnormalities in the majority of patients. Although right ventricular volume load due to severe pulmonary regurgitation can be tolerated for many years, there is now evidence that the compensatory mechanisms of the right ventricular myocardium ultimately fail and that if the volume load is not eliminated or reduced by pulmonary valve replacement the dysfunction might be irreversible. Cardiovascular magnetic resonance (CMR) has evolved during the last 2 decades as the reference standard imaging modality to assess the anatomic and functional sequelae in patients with repaired TOF. This article reviews the pathophysiology of chronic right ventricular volume load after TOF repair and the risks and benefits of pulmonary valve replacement. The CMR techniques used to comprehensively evaluate the patient with repaired TOF are reviewed and the role of CMR in supporting clinical decisions regarding pulmonary valve replacement is discussed. PMID:21251297

Colombian experience with transcatheter aortic valve implantation of medtronic CoreValve.

Science.gov (United States)

Dager, Antonio E; Nuis, Rutger-Jan; Caicedo, Bernardo; Fonseca, Jaime A; Arana, Camilo; Cruz, Lidsa; Benitez, Luis M; Nader, Carlos A; Duenas, Eduardo; de Marchena, Eduardo J; O'Neill, William W; de Jaegere, Peter P

2012-01-01

At our institutions, increasing numbers of aortic stenosis patients were not candidates for surgical aortic valve replacement. Accordingly, we initiated the Cali Colombian Transcatheter Aortic Valve Implantation (TAVI) program. From March 2008 through January 2011, 53 consecutive patients (mean age, 79 ± 6 yr; men, 58%) underwent TAVI with the Medtronic CoreValve System, and data were prospectively collected. Our study's endpoints conformed with Valve Academic Research Consortium recommendations. We report our clinical results.Predicted mortality rates were 25% (interquartile range, 17%-34%) according to logistic EuroSCORE and 6% (interquartile range, 3%-8%) according to the Society of Thoracic Surgeons score. The 30-day mortality rate was 9% (3 intraprocedural deaths, 5 total). The combined 30-day safety endpoint was 30% (major vascular sequelae, 23%; life-threatening bleeding, 12%; myocardial infarction, 4%; major stroke, 4%; and acute kidney injury [stage 3], 2%). Eight patients (15%) required post-implantation balloon dilation and 2 (4%) required valve-in-valve implantation, for a technical device success rate of 77%. Mean peak transvalvular gradient decreased from 74 ± 29 to 17 ± 8 mmHg and mean transvalvular gradient from 40 ± 17 to 8 ± 4 mmHg (both P=0.001). Moderate or severe aortic regurgitation decreased from 32% to 18% (P=0.12) and mitral regurgitation from 32% to 13% (P=0.002). The 1-year survival rate was 81%.We found that TAVI with the CoreValve prosthesis was safe and feasible, with sustained long-term results, for treating aortic stenosis in patients at excessive surgical risk; nonetheless, serious adverse events occurred in 30% of the patients.

Traumatic Mitral Valve and Pericardial Injury

Directory of Open Access Journals (Sweden)

Nissar Shaikh

2013-01-01

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

Lipoprotein(a Induces Human Aortic Valve Interstitial Cell Calcification

Directory of Open Access Journals (Sweden)

Bin Yu, PhD

2017-08-01

Full Text Available Lipoprotein(a, or Lp(a, significantly increased alkaline phosphatase activity, release of phosphate, calcium deposition, hydroxyapatite, cell apoptosis, matrix vesicle formation, and phosphorylation of signal transduction proteins; increased expression of chondro-osteogenic mediators; and decreased SOX9 and matrix Gla protein (p < 0.001. Inhibition of MAPK38 and GSK3β significantly reduced Lp(a-induced calcification of human aortic valve interstitial cells (p < 0.001. There was abundant presence of Lp(a and E06 immunoreactivity in diseased human aortic valves. The present study demonstrates a causal effect for Lp(a in aortic valve calcification and suggests that interfering with the Lp(apathway could provide a novel therapeutic approach in the management of this debilitating disease.

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

Science.gov (United States)

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

2001-09-01

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

Fairchild Stratos Division's Type II prototype lockhopper valve: METC Prototype Test Valve No. F-1 prototype lockhopper valve-testing and development project. Static test report

Energy Technology Data Exchange (ETDEWEB)

Goff, D. R.; Cutright, R. L.; Griffith, R. A.; Loomis, R. B.; Maxfield, D. A.; Moritz, R. S.

1981-10-01

METC Prototype Test Valve No. F-1 is a hybrid design, based on a segmented ball termed a visor valve, developed and manufactured by Fairchild Stratos Division under contract to the Department of Energy. The valve uses a visor arm that rotates into position and then translates to seal. This valve conditionally completed static testing at METC with clean gas to pressures of 1600 psig and internal valve temperatures to 600/sup 0/F. External leakage was excessive due to leakage through the stuffing box, purge fittings, external bolts, and other assemblies. The stuffing box was repacked several times and redesigned midway through the testing, but external leakage was still excessive. Internal leakage through the seats, except for a few anomalies, was very low throughout the 2409 cycles of testing. As shown by the low internal leakage, the visor valve concept appears to have potential for lock-hopper valve applications. The problems that are present with METC Prototype Test Valve No. F-1 are in the seals, which are equivalent to the shaft and bonnet seals in standard valve designs. The operating conditions at these seals are well within the capabilities of available seal designs and materials. Further engineering and minor modifications should be able to resolve the problems identified during static testing.

Balloon valvuloplasty in dysplastic pulmonary valve stenosis: immediate and intermediate outcomes

International Nuclear Information System (INIS)

Sehar, T.; Qureshi, A.U.; Kazmi, U.; Mehmood, A.

2015-01-01

To determine the immediate and intermediate outcome in dysplastic and doming pulmonary valve stenosis in children and to determine various factors associated with unsuccessful outcome. Study Design: An interventional study. Place and Duration of Study: The Children's Hospital, Lahore, Pakistan, from June 2006 to December 2012. Methodology: All patients presenting with severe pulmonary valve stenosis were enrolled in the study. Balloon valvuloplasty was performed on all patients. Successful outcome (residual gradient 75 mmHg was the most significant factor associated with unsuccessful outcome (p 60 mmHg was the only significant factor associated with re-intervention in group A (p=0.001). Conclusion: The results from balloon valvuloplasty in dysplastic pulmonary valve were suboptimal when compared to doming valves. However, it provides a high freedom from re-intervention rate in intermediate follow-up. Intervention at moderate severity can result in better outcome. (author)

Development of a butterfly check valve model under natural circulation conditions

International Nuclear Information System (INIS)

Rao, Yuxian; Yu, Lei; Fu, Shengwei; Zhang, Fan

2015-01-01

Highlights: • Bases on Lim’s swing check valve model, a butterfly check valve model was developed. • The method to quantify the friction torque T F in Li’s model was corrected. • The developed model was implemented into the RELAP5 code and verified. - Abstract: A butterfly check valve is widely used to prevent a reverse flow in the pipe lines of a marine nuclear power plant. Under some conditions, the natural circulation conditions in particular, the fluid velocity through the butterfly check valve might become too low to hold the valve disk fully open, thereby the flow resistance of the butterfly check valve varies with the location of the valve disk and as a result the fluid flow is significantly affected by the dynamic motion of the valve disk. Simulation of a pipe line that includes some butterfly check valves, especially under natural circulation conditions, is thus complicated. This paper focuses on the development of a butterfly check valve model to enhance the capability of the thermal–hydraulic system code and the developed model is implemented into the RELAP5 code. Both steady-state calculations and transient calculations were carried out for the primary loop system of a marine nuclear power plant and the calculation results are compared with the experimental data for verification purpose. The simulation results show an agreement with the experimental data

Stent valve implantation in conventional redo aortic valve surgery to prevent patient-prosthesis mismatch.

Science.gov (United States)

Ferrari, Enrico; Franciosi, Giorgio; Clivio, Sara; Faletra, Francesco; Moccetti, Marco; Moccetti, Tiziano; Pedrazzini, Giovanni; Demertzis, Stefanos

2017-03-01

The goal was to show the technical details, feasibility and clinical results of balloon-expandable stent valve implantation in the aortic position during conventional redo open-heart surgery in selected obese patients with a small aortic prosthesis and severe patient-prosthesis mismatch. Two symptomatic overweight patients (body mass index of 31 and 38), each with a small aortic prosthesis (a 4-year-old, 21-mm Hancock II biological valve and a 29-year-old, 23-mm Duromedic mechanical valve), increased transvalvular gradients (59/31 and 74/44 mmHg) and a reduced indexed effective orifice area (0.50 and 0.43 cm 2 /m 2 ) underwent implantation of two 26-mm balloon-expandable Sapien 3 valves during standard on-pump redo valve surgery. Using full re-sternotomy, cardiopulmonary bypass and cardioplegic arrest, the two balloon-expandable stent valves were implanted under direct view using a standard aortotomy, after prosthesis removal and without annulus enlargement. Aortic cross-clamp times were 162 and 126 min; cardiopulmonary bypass times were 178 and 180 min; total surgical times were 360 and 318 min. At discharge, echocardiograms showed transvalvular peak and mean gradients of 13/9 and 23/13 mmHg and indexed effective orifice areas of 0.64 and 1.08 cm 2 /m 2 . The 3-month echocardiographic follow-up showed transvalvular peak and mean gradients of 18/9 and 19/11 mmHg and indexed effective orifice areas of 0.78 cm 2 /m 2 and 0.84 cm 2 /m 2 , with improved symptoms (New York Heart Association class 1). Implantation of a balloon-expandable stent valve during redo aortic valve surgery is feasible in selected cases and prevents patient-prosthesis mismatch in obese patients without need for aortic annulus enlargement. Moreover, in the case of stent valve degeneration, this approach permits additional valve-in-valve procedures with large stent valves and prevents re-redo surgery. © The Author 2016. Published by Oxford University Press on behalf of the

Cyclonic valve test: preliminary results

Energy Technology Data Exchange (ETDEWEB)

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

2012-07-01

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

Bioprinting a cardiac valve.

Science.gov (United States)

Jana, Soumen; Lerman, Amir

2015-12-01

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

Bicuspid aortic valve demonstrated with multislice computed tomography - a case report

International Nuclear Information System (INIS)

Marzec, M.; Lasek, W.; Serafin, Z.; Laskowska, K.; Swiatkiewicz, I.; Kubica, J.

2004-01-01

Bicuspid aortic valve (BAV) is one of the most common congenital heart defects and often coexists with other congenital abnormalities of the heart and great vessels. A standard diagnostic technique for valve imaging is echocardiography. However, suboptimal images may cause a diagnostic problem, especially in obese patients, women and in case of significant valve calcifications. The paper reports a case of a 27-year-old male patient with recurrent chest pain, appearing regardless of exertion. Routine physical examination, laboratory tests and echocardiography were negative. Multislice computed tomography (MSCT) showed normal coronary arteries and bicuspid aortic valve. The diagnostics of bicuspid aortic valve and the diagnostic value of MSCT are discussed. MSCT seems to be an important point in cardiac diagnostic algorithms, being an alternative modality for MR in BAV imaging. The presented case emphasizes the potential of MSCT for the diagnostics of cardiac valve congenital diseases. (author)

CLINICAL AND FUNCTIONAL ASSESSMENT OF THE BIOLOGICAL PROSTHESIS “ASPIRE” FOR SURGICAL CORRECTION OF MITRAL VALVE DISEASE

Directory of Open Access Journals (Sweden)

S. G. Esin

2015-01-01

Full Text Available Aim: To assess clinical and functional efficacy of implanted biological prosthesis “ASPIRE” (manufactured by Vascutek for correction of mitral valve disease.Materials and methods: From October 2008 to December 2013, biological prostheses “ASPIRE” (Vascutek were implanted to 34 patients with mitral valve disease (mean age 63.59 ± 4.96 years, 79.4% female. From these, 24 patients had mitral stenosis and 10 patients had mitral insufficiency. 73.5% of all patients had heart failure Strazhesko-Vasilenko IIA grade and 85.3% of patients had chronic heart failure NYHA III. Isolated mitral valve replacement was performed only in 8 (23.5% of patients. In 22 (64.7% of cases mitral valve replacement was combined with tricuspid valvuloplasty in various modifications. Duration of cardiopulmonary bypass and of aortic clamping was 88.09 ± 25.95 and 65.68 ± 25.51 minutes, respectively. Before and after surgery all patients underwent echocardiographic assessment and clinical assessment of their general status.Results: In-hospital mortality was 5.88% (n = 2 and was related to multiorgan failure in the early postoperative period. All 32 (94.12% surviving patients improved with decrease or complete disappearance of heart failure. Postoperative complications were typical for cardiac surgery. There were no episodes of embolism, structural dysfunction, thrombosis of the prosthesis and endocarditis of the prosthesis in the early postoperative period. Pressure gradients across prosthetic valves were not high and corresponded to good clinical and hemodynamic results in the early postoperative period.Conclusion: Taking into account good immediate results of mitral valve replacement, as well as no need in lifelong anticoagulation in patients with multiple concomitant disorders, implantation of the biological prosthesis “ASPIRE” (Vascutek could become a procedure of choice for correction of valve abnormalities in patients above 65 years. For more comprehensive

Coronary artery disease in patients undergoing valve replacement at a tertiary care cardiac centre

International Nuclear Information System (INIS)

Shaikh, A.H.; Hanif, B.; Hasan, K.; Hashmani, S.

2011-01-01

To determine the prevalence of coronary artery disease in patients undergoing valve surgery at a tertiary care cardiac centre. The medical records of 144 consecutive patients who underwent mitral, aortic or dual (mitral and aortic) valve replacement surgery at the Tabba Heart Institute between January 2006 to December 2008 were retrospectively reviewed. All patients underwent coronary angiogram. Significant coronary artery disease (CAD) is defined as coronary stenosis of > 50%. There were 74 (51.4%) males and 70 (48.6%) females in the study. The mean age was 51.64 +- 11 years. Of all, 73 (50.7%) underwent mitral valve replacement, 47 (32.6%) had aortic and 24 (16.7%) had dual valve replacement. Out of 144 patients, 99 (68.8%) had 50% stenosis. In patients who had undergone mitral valve replacement (MVR), significant coronary disease was found in 32.9%, whereas in patients who had undergone aortic valve replacement (AVR) and dual valve replacement (DVR) the prevalence of coronary disease was 31.9% and 25% respectively. Our results suggest that the overall prevalence of coronary artery disease in patients undergoing valve surgery in our population is comparable with prevalence reported in international data. (author)

Diseases of the Tricuspid Valve

Science.gov (United States)

... stenosis. Tricuspid Regurgitation Tricuspid regurgitation is also called tricuspid insufficiency or tricuspid incompetence. It means there is a ... require valve surgery. Tags: heart valves , tricuspid incompetence , ... tricuspid regurgitation , tricuspid stenosis , valve disease Related Links ...

A modelling study into the effects of variable valve timing on the gas exchange process and performance of a 4-valve DI homogeneous charge compression ignition (HCCI) engine

International Nuclear Information System (INIS)

Mahrous, A-F.M.; Potrzebowski, A.; Wyszynski, M.L.; Xu, H.M.; Tsolakis, A.; Luszcz, P.

2009-01-01

Homogeneous charge compression ignition (HCCI) combustion mode is a relatively new combustion technology that can be achieved by using specially designed cams with reduced lift and duration. The auto-ignition in HCCI engine can be facilitated by adjusting the timing of the exhaust-valve-closing and, to some extent, the timing of the intake-valve-opening so as to capture a proportion of the hot exhaust gases in the engine cylinder during the gas exchange process. The effects of variable valve timing strategy on the gas exchange process and performance of a 4-valve direct injection HCCI engine were computationally investigated using a 1D fluid-dynamic engine cycle simulation code. A non-typical intake valve strategy was examined; whereby the intake valves were assumed to be independently actuated with the same valve-lift profile but at different timings. Using such an intake valves strategy, the obtained results showed that the operating range of the exhaust-valve-timing within which the HCCI combustion can be facilitated and maintained becomes much wider than that of the typical intake-valve-timing case. Also it was found that the engine parameters such as load and volumetric efficiency are significantly modified with the use of the non-typical intake-valve-timing. Additionally, the results demonstrated the potential of the non-typical intake-valve strategy in achieving and maintaining the HCCI combustion at much lower loads within a wide range of valve timings. Minimizing the pumping work penalty, and consequently improving the fuel economy, was shown as an advantage of using the non-typical intake-valve-timing with the timing of the early intake valve coupled with a symmetric degree of exhaust-valve-closing timing

A modelling study into the effects of variable valve timing on the gas exchange process and performance of a 4-valve DI homogeneous charge compression ignition (HCCI) engine

Energy Technology Data Exchange (ETDEWEB)

Mahrous, A-F.M. [School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Lecturer at the Department of Mechanical Power Engineering, Faculty of Engineering (Shebin El-Kom), Menoufiya University, Shebin El-Kom (Egypt); Potrzebowski, A.; Wyszynski, M.L.; Xu, H.M.; Tsolakis, A.; Luszcz, P. [School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

2009-02-15

Homogeneous charge compression ignition (HCCI) combustion mode is a relatively new combustion technology that can be achieved by using specially designed cams with reduced lift and duration. The auto-ignition in HCCI engine can be facilitated by adjusting the timing of the exhaust-valve-closing and, to some extent, the timing of the intake-valve-opening so as to capture a proportion of the hot exhaust gases in the engine cylinder during the gas exchange process. The effects of variable valve timing strategy on the gas exchange process and performance of a 4-valve direct injection HCCI engine were computationally investigated using a 1D fluid-dynamic engine cycle simulation code. A non-typical intake valve strategy was examined; whereby the intake valves were assumed to be independently actuated with the same valve-lift profile but at different timings. Using such an intake valves strategy, the obtained results showed that the operating range of the exhaust-valve-timing within which the HCCI combustion can be facilitated and maintained becomes much wider than that of the typical intake-valve-timing case. Also it was found that the engine parameters such as load and volumetric efficiency are significantly modified with the use of the non-typical intake-valve-timing. Additionally, the results demonstrated the potential of the non-typical intake-valve strategy in achieving and maintaining the HCCI combustion at much lower loads within a wide range of valve timings. Minimizing the pumping work penalty, and consequently improving the fuel economy, was shown as an advantage of using the non-typical intake-valve-timing with the timing of the early intake valve coupled with a symmetric degree of exhaust-valve-closing timing. (author)

Vent-induced prosthetic leaflet thrombosis treated by open-heart valve-in-valve implantation.

Science.gov (United States)

Stamm, Christof; Pasic, Miralem; Buz, Semih; Hetzer, Roland

2015-09-01

A patient required emergency mitral valve replacement and extracorporeal membrane oxygenation (ECMO) support for acute biventricular failure. The left ventricular (LV) vent inserted via the left upper pulmonary vein induced thrombotic immobilization of a prosthetic valve leaflet, with significant intra-prosthesis regurgitation after ECMO explantation. Therefore, the left atrium was opened on the beating heart during conventional extracorporeal circulation, all prosthesis leaflets were excised and a 29-mm expandable Edwards Sapien prosthesis was inserted within the scaffold of the original prosthesis under direct vision. This case illustrates the benefits and potential problems of LV venting on ECMO support, and a rapid and safe way of replacing the prosthesis leaflets in a critical situation. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Multimodality Imaging of Heart Valve Disease

International Nuclear Information System (INIS)

Rajani, Ronak; Khattar, Rajdeep; Chiribiri, Amedeo; Victor, Kelly; Chambers, John

2014-01-01

Unidentified heart valve disease is associated with a significant morbidity and mortality. It has therefore become important to accurately identify, assess and monitor patients with this condition in order that appropriate and timely intervention can occur. Although echocardiography has emerged as the predominant imaging modality for this purpose, recent advances in cardiac magnetic resonance and cardiac computed tomography indicate that they may have an important contribution to make. The current review describes the assessment of regurgitant and stenotic heart valves by multimodality imaging (echocardiography, cardiac computed tomography and cardiac magnetic resonance) and discusses their relative strengths and weaknesses

Multimodality Imaging of Heart Valve Disease

Energy Technology Data Exchange (ETDEWEB)

Rajani, Ronak, E-mail: Dr.R.Rajani@gmail.com [Department of Cardiology, St. Thomas’ Hospital, London (United Kingdom); Khattar, Rajdeep [Department of Cardiology, Royal Brompton Hospital, London (United Kingdom); Chiribiri, Amedeo [Divisions of Imaging Sciences, The Rayne Institute, St. Thomas' Hospital, London (United Kingdom); Victor, Kelly; Chambers, John [Department of Cardiology, St. Thomas’ Hospital, London (United Kingdom)

2014-09-15

Unidentified heart valve disease is associated with a significant morbidity and mortality. It has therefore become important to accurately identify, assess and monitor patients with this condition in order that appropriate and timely intervention can occur. Although echocardiography has emerged as the predominant imaging modality for this purpose, recent advances in cardiac magnetic resonance and cardiac computed tomography indicate that they may have an important contribution to make. The current review describes the assessment of regurgitant and stenotic heart valves by multimodality imaging (echocardiography, cardiac computed tomography and cardiac magnetic resonance) and discusses their relative strengths and weaknesses.

Leaflet escape in a new bileaflet mechanical valve: TRI technologies.

Science.gov (United States)

Bottio, Tomaso; Casarotto, Dino; Thiene, Gaetano; Caprili, Luca; Angelini, Annalisa; Gerosa, Gino

2003-05-13

Leaflet escape is a mode of structural valve failure for mechanical prostheses. This complication previously has been reported for both monoleaflet and bileaflet valve models. We report 2 leaflet escape occurrences observed in 2 patients who underwent valve replacement with a TRI Technologies valve prosthesis. At the University of Padua, between November 2000 and February 2002, 36 TRI Technologies valve prostheses (26 aortic and 10 mitral) were implanted in 34 patients (12 women and 22 men) with a mean age of 59.9+/-10.3 years (range, 30 to 75 years). There were 5 deaths: 3 in hospital, 1 early after discharge, and 1 late. Two patients experienced a catastrophic prosthetic leaflet escape; the first patient was a 52-year-old man who died 10 days after aortic valve and ascending aorta replacement, and the second was a 58-year-old man who underwent a successful emergency reoperation 20 months after mitral valve replacement. Examination of the explanted prostheses showed in both cases a leaflet escape caused by a leaflet's pivoting system fracture. Prophylactic replacement was then successfully accomplished so far in 12 patients, without evidence of structural valve failure in any of them. Among other significant postoperative complications, we observed 3 major thromboembolisms, 1 hemorrhage, and 1 paravalvular leak. These catastrophes prompted us to interrupt the implantation program, and they cast a shadow on the durability of the TRI Technologies valve prosthesis because of its high risk of structural failure.

Prior oral conditions in patients undergoing heart valve surgery.

Science.gov (United States)

Silvestre, Francisco-Javier; Gil-Raga, Irene; Martinez-Herrera, Mayte; Lauritano, Dorina; Silvestre-Rangil, Javier

2017-11-01

Patients scheduled for heart valve surgery should be free of any oral infectious disorders that might pose a risk in the postoperative period. Few studies have been made on the dental conditions of such patients prior to surgery. The present study describes the most frequent prior oral diseases in this population group. A prospective, observational case-control study was designed involving 60 patients (30 with heart valve disease and 30 controls, with a mean age of 71 years in both groups). A dental exploration was carried out, with calculation of the DMFT (decayed, missing and filled teeth) index and recording of the periodontal parameters (plaque index, gingival bleeding index, periodontal pocket depth, and attachment loss). The oral mucosa was also examined, and panoramic X-rays were used to identify possible intrabony lesions. Significant differences in bacterial plaque index were observed between the two groups ( p <0.05), with higher scores in the patients with valve disease. Probing depth and the presence of moderate pockets were also greater in the patients with valve disease than among the controls ( p <0.01). Sixty percent of the patients with valve disease presented periodontitis. Patients scheduled for heart valve surgery should be examined for possible active periodontitis before the operation. Those individuals found to have periodontal disease should receive adequate periodontal treatment before heart surgery. Key words: Valve disease, aortic, mitral, heart surgery, periodontitis.

Optimal results of aortic valve replacement with small mechanical valves (< 19 mm).

Science.gov (United States)

Kato, Yasuyuki; Hattori, Koji; Motoki, Manabu; Takahashi, Yosuke; Kotani, Shinsuke; Nishimura, Shinsuke; Shibata, Toshihiko

2013-07-01

Controversy exists regarding the optimal operative method or type of prosthesis for patients with a small aortic root. The aim of this retrospective study was to investigate the early and mid-term outcomes of standard aortic valve replacement (AVR) using 16 mm or 18 mm ATS Advanced Performance (AP) or 17 mm St. Jude Medical (SJM) Regent valves for a small aortic root. Between April 2003 and August 2009, 78 patients (age range: 50-86 years; 86% aged > or = 65 years) underwent AVR with 16 mm or 18 mm ATS AP valves (16AP group: n = 21, 18AP group: n = 32), or a 17 mm SJM Regent valve (17Regent group: n = 25). Fifty-six patients (72%) had a body surface area (BSA) of regression was similar among the groups (-30%, -25% and -28% in the 16AP, 17Regent and 18AP groups, respectively; p = 0.844). The early and mid-term results of AVR with 16 mm or 18 mm ATS AP valves, or with a 17 mm SJM Regent valve, were satisfactory. Therefore, standard AVR using these small mechanical prostheses, which avoids the need to enlarge the annulus or to conduct stentless bioprosthesis implantation, might represent an acceptable method, especially in elderly patients with a small aortic root.

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-05-15

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