Large Valve Research Articles

Supra-Annular Mitral Valve Replacement in Children

Despite improved mitral repair techniques, some children need mitral valve replacement (MVR). Due to small annulus size, supra-annular MVR is useful. From 2003 to 2010, 15 children had 23 supra-annular MVRs. At first supra-annular MVR, median age was 6.5 months (28 days to 47 months); median weight was 5.4 kg (3.3-11.8 kg). Twelve (80%) had prior operations, 8 (53%) had previous mitral repair. Eight had congenital mitral anomalies (4 with Shone's), 5 had atrioventricular septal defects, 1 had endocarditis, and 1 had a repaired anomalous left coronary artery. All primary MVRs used mechanical valves (≤ 17 mm in 9 patients). There was one early death (93% survival) in an 11-month-old with congenital pulmonary vein stenosis. One intraoperative conversion from annular to supra-annular MVR developed heart block. Three pacemakers were implanted for supraventricular rhythm disturbances. Three children had valve thrombosis early postoperatively treated medically. On follow-up of 4.3 ± 2.8 years, 8 had reoperation including redo MVR in 6 for pannus formation or thrombus (1 had three redo MVRs). At redo, a larger valve was used in 5 and a bioprosthetic valve in 4 patients. There was one late death after third redo MVR with pulmonary vein stenosis relief (overall survival 87%). Supra-annular MVR is useful for children with a small annulus. Operative survival is good with infrequent heart block. Complications are common, including redo MVR and need for left ventricular outflow tract obstruction relief. Pulmonary vein stenosis is a marker for poor outcome; all patients without pulmonary vein stenosis survive long term.

Left Ventricular Pseudoaneurysm

Left ventricular (LV) pseudoaneurysm is rare in children. This report describes the case of a 2-year-old previously healthy girl who was diagnosed with endocarditis and underwent resection of a large mitral valve vegetation from the posterior mitral leaflet. One month after this surgery, she was diagnosed with a large LV pseudoaneurysm based on echocardiography performed during routine outpatient follow-up. Cardiac surgery was performed urgently to address the pseudoaneurysm, given its potential to rupture spontaneously. This case emphasizes the need for a close follow-up of children with endocarditis for development of pseudoaneurysms, which is a rare but potentially fatal complication of endocarditis.

Revival of Continuous Suture Technique in Aortic Valve Replacement in Patient with Aortic Valve Stenosis a Novel Modified Technique

: The continuous suture technique has numerous advantages as simple, quick, and effective for aortic valve replacement; however, it is technically difficult. We have modified the continuous suture technique and evaluated our new technique in patients with aortic stenosis. : Between July 2007 and May 2010, 86 patients with aortic valve stenosis underwent aortic valve replacement alone or with other concomitant cardiac procedures including mitral valve surgery in our hospital. The patients were randomly divided into two groups: group A (n = 43) in which the continuous suture technique with some modifications was used and group B (n = 43) in which the conventional interrupted suture technique was used. There were no statistical differences between two groups in age, sex, body surface area, concomitant cardiac procedures, blood loss, and postoperative extubation time. : The aortic cross-clamp time, cardiopulmonary bypass time, operation time, and hospital stay were significantly shorter in group A than that in group B, and the valve size was significantly larger in group A. No perivalvular leak was detected in postoperative echocardiograms. All patients recovered satisfactorily without complications associated with suture technique or prosthesis. During follow-up of 4 to 38 months, there were no clinically significant complications in group A, while one patient in group B developed perivalvular leakage requiring reoperation 3 months after surgery. : Our modified continuous suture method is useful for aortic valve replacement in patients with aortic stenosis and beneficial for the patients because the procedure is less invasive and a larger valve can be implanted.

THE PREVALENCE OF EUSTACHIAN VALVE ON TRANSOESOPHAGEAL ECHO EXAMINATION

The Eustachian valve (EV) is an embryonic structure redirecting the blood flow from the inferior vena cava through the foramen ovale. It may persist in adults as a floating membrane in the right atrium. A large EV can be associated with thrombosis, embolization, bacterial endocarditis, etc. The prevalence of EV in the normal population is unknown. to assess the prevalence and size of EV in unselected patients examined by transoesophageal echo. Methods. 1100 consecutive patients were examined for various reasons by a single operator and interpreter. Routine check was made for the presence of EV in the right atrium. Only patients with a mobile EV and not with a simple rigid rim were counted. Three measurements of the EV length at the level of the aortic valve (i.e. 90°C) were made off-line and the longest distance considered. If the EV was not visualized and recorded as a straight line because of its chaotic movement, the picture of the valve was segmented into several separated valve portions and the sum taken as the true length. 46 patients (24 males) with EV were identified out of total 1100 pts examined. The average length of the EV was 23.6 ± 9.7 mm (7-47 mm, median 23 mm). The finding of a persisting Eustachian valve on transoesophageal echo examination is not rare. The prevalence was similar in men and in women. Bearing in mind the possible complications associated with a large valve, we recommend that a proper description of persistent EV is included in routine transoesophageal echo reports.

A solid hydraulically amplified piezoelectric microvalve

We report a piezoelectrically driven and hydraulically amplified axial polymer microvalve. The microvalve is normally open and is assembled primarily with stereolithographically fabricated polymer components. An incompressible elastomer is used as a solid hydraulic medium to convert the small axial displacement of a piezoelectric actuator into a large valve head stroke while maintaining a large blocking force. Also, the axial design of the microvalve enables densely packed valve arrays. One application of this microvalve is in pneumatic tactile displays, which operates against gas pressure up to approximately 90 kPa and switching speed between 1 and 200 Hz. The current valve design has a maximum static hydraulic amplification ratio of 5 at 30 V driving voltage and a maximum valve head stroke of 37 µm at 150 V. Under a 94.4 kPa differential pressure, the flow rate of the valve and the closing voltage measure are 785 mL min−1 and 150 V, respectively. The function of the microvalve as an on–off switch for a pneumatic microbubble tactile actuator is demonstrated.

¿Debe operarse la trombosis protésica mitral grande no oclusiva?

Large prosthetic thrombosis, thrombus >5 mm or >0.8 cm 2, is associated with high morbidity and mortality. We present a series of 9 cases of large non-obstructive prosthetic thrombosis in the mitral position. The initial treatment was anticoagulation therapy in 4 patients, fibrinolysis in 3 and surgery in 2. Surgery was required as the definitive treatment in 8 of the 9 patients (89%). The mean time to surgery was 6.7 days from hospital admission and 70.2 days for patients who were readmitted, with a mean increase in the Euroscore of 9.05% and a surgery success rate of 63%. Total early mortality was 33%, reaching 55% during follow-up. Surgery is probably the most effective treatment for large prosthetic mitral valve thrombosis, and delay in therapeutic decision-making implies an increase in mortality. Optimal anticoagulant and fibrinolytic therapy are often not definitive and not without complications.

Dynamic Characteristics Analysis of High Water-Based Large Flow Safety Valve

The FAD3000/50 safety valve is researched that is newly developed by Zhengzhou Coal Mining Machinery Group Co.,Ltd with high water-based pressure ultra great current capacity. The mathematical model is fistly established according to the study of its structure and the practical system on hydraulic support. The simulation computation has carried under the MATLAB software, and this simulation model has confirmed through the test result. After a comparison of multiple sets of simulation results, the influence of primary structure parameter’s change in safety valve to dynamic characteristics is gived.

Spin Injection Into Magnesium Nanowire

Spin injection into magnesium from Permalloy is performed in the lateral spin valve geometry. A large spin valve signal of 3.1 mΩ is observed at room temperature. The injector-detector separation dependence of the spin valve signal is analyzed by using a one-dimensional spin-diffusion model. The analysis yields the spin diffusion length of about 200 nm for the Mg nanowires. The short spin diffusion length of magnesium which has a small spin-orbit interaction can possibly be explained by considering the spin-hot-spot relaxation mechanism proposed by Fabian and Das Sarma.

The negative ion source test facility ELISE

The ITER neutral beam system is using inductively coupled radio frequency (RF) ion sources, that have demonstrated the required ITER parameters on (small) sources with extraction areas up to 200 cm 2. As a next step towards the full size ITER source IPP is presently constructing the test facility ELISE (“Extraction from a Large Ion Source Experiment”) operating with a “half-size” source which has approximately the width but only half the height of the ITER source. The modular driver concept is expected to allow a further extrapolation to the full size in one direction to be made. The main aim of this experiment is to demonstrate the production of a large uniform negative ion beam with ITER relevant parameters in stable conditions up to one hour. Plasma operation of the source is foreseen to be performed continuously for 1 h; extraction and acceleration of negative ions up to 60 kV is only possible in pulsed mode (10 s every 180 s) due to limitations of the existing IPP HV system. The design of the source and extraction system implements a high experimental flexibility and a good diagnostic access while still staying as close as possible to the ITER design. The main differences are the source operating in air and the use of a large gate valve between the source and the target chamber. ELISE is expected to start operation at the end of 2011 and is an important step for the development of the ITER NBI system; the experience gained early will support the design as well as the commissioning and operating phases of the PRIMA NBI test facilities and the ITER neutral beam system.

Potentially fatal tricuspid valve aspergilloma detected after laparoscopic abdominal surgery

Fungal endocarditis accounts for 1.3-6% of all cases of infective endocarditis. The most common causative organism is Candida, followed by Aspergillus and other mould fungi. Aspergillus endocarditis is usually associated with high morbidity and mortality. Establishing a definitive and timely diagnosis remains difficult and there are many reports of undetected aspergillomas leading to fatalities in the perioperative period. We present a case report of preoperatively undiagnosed large mobile tricuspid valve aspergilloma obstructing the right ventricular inlet, diagnosed incidentally on the second postoperative day after laparoscopic pancreatic abscess drainage. The patient was successfully managed with emergency open-heart surgery and systemic antifungal agents in the postoperative period.

Impressive Echocardiographic Images of a Mitral Valve Aneurysm

A 77-year-old woman with a fractured femur was referred to our hospital because preoperative echocardiography raised suspicion of a mitral valve tumor. She had no history of unknown fever or heart murmur. Transthoracic and transesophageal echocardiography showed severe mitral regurgitation and aortic regurgitation. A mobile lesion that appeared to be a cystic tumor (14×15 mm) was on the posterior mitral leaflet (Figure 1 and Movie in the online-only Data Supplement). The lesion had no color Doppler signal inside. Computed tomography showed a cystic mass with homogeneously enhanced contents (Figure 2). During the period of recovery from her hip surgery, the patient developed a sporadic febrile illness, and Enterococcus faecium was cultured from a blood …

Measurement of Aortic Valve Annulus Using Different Cardiac Imaging Techniques in Transcatheter Aortic Valve Implantation: Agreement with Finally Implanted Prosthesis Size

To compare the measurements of the aortic annulus obtained with various imaging techniques in patients with severe aortic stenosis scheduled for transcatheter aortic valve implantation, and to determine the grade of agreement between the predicted size of the prosthesis for each technique, and the size of the finally implanted valve. The aortic annulus was measured in 40 patients treated by transcatheter aortic valve implantation (CoreValve aortic valve) with transthoracic (TTE) and transesophageal echocardiography (TEE), 64-slice tomography, and angiography. A large valve was implanted when annulus was >23 mm and a small one if it was ≤23 mm. If the size of the prosthesis predicted by several techniques was not the same in one case, we selected the size in which more techniques presented agreement. Forty aortic valves, 26 small and 14 large, were implanted percutaneously. The best correlation was obtained with TTE and TEE (r = 0.93, P < 0.001). The correlation of TTE and TEE with angiography also was good (r = 0.58, P < 0.001 and r = 0.53, P < 0.001, respectively). Correlations between these techniques and computed tomography were poor (P = NS for all comparisons). The best agreement between estimated aortic annulus and implanted valve size was obtained with transtoracic and TEE (κ= 0.88 and 0.76). The aortic annulus measurements obtained by TTE, TEE, and angiography correlated well, while tomography correlated poorly with other techniques. The imaging techniques that showed the best agreement between estimated aortic annulus size and implanted aortic valve size were TTE and TEE.

The “Intelligent” Valve: A Diagnostic Framework for Integrated System-Health Management of a Rocket-Engine Test Stand

Valves play a critical role in rocket-engine test stands because they are essential for the cryogen transport mechanisms that are vital to test operations. Sensors that are placed on valves monitor the pressure, temperature, flow rate, valve position, and any other features that are required for diagnosing their functionality. Integrated system-health management (ISHM) algorithms have been used to identify and evaluate anomalous operating conditions of systems and subsystems (e.g., valves and valve components) on complex structures, such as rocket test stands. In order for such algorithms to be useful, there is a need to develop realistic models for the most common and problem-prone elements. Furthermore, the user needs to be provided with efficient tools to explore the nature of the anomaly and its possible effects on the element, as well as its relationship to the overall system state. This paper presents the development of an intelligent-valve framework that is capable of tracking and visualizing events of the large linear actuator valve (LLAV) in order to detect anomalous conditions. The framework employs a combination of technologies, including a dynamic data exchange data-transfer protocol, autoassociative neural networks, empirical and physical models, and virtual-reality environments. The diagnostic procedure that is developed has the ability to be integrated into existing ISHM systems and can be used for assessing the integrity of rocket-engine test-stand components.

Performance of different continuous positive airway pressure helmets equipped with safety valves during failure of fresh gas supply

We assessed the performance of different continuous positive airway pressure (CPAP) helmets equipped with a safety valve during discontinuation of fresh gas flow. This was a physiological study of five healthy volunteers. We delivered CPAP (fresh gas flow 60 l/min, FiO(2) 60%, PEEP 5 cmH(2)O) with three different helmets in a random sequence: 4Vent (Rüsch), HelmHAR-cp (Harol) and CaStar CP210 (StarMed). For each helmet we randomly applied, for up to 4 min, three disconnections of fresh gas flow: helmet inlet (D(inlet)), flowmeter (D(flowmeter)) and gas source (D(source)). We continuously recorded from a nostril: end-tidal CO(2) (PetCO(2)), inspiratory CO(2) (PiCO(2)), fraction of inspired oxygen (FiO(2)) and respiratory rate (RR). During every disconnection we observed an increase in PiCO(2) and PetCO(2) with a drop in FiO(2), while RR did not change. FiO(2) decreased more quickly in the CaStar, equipped with the largest safety valve, during D(source) and D(flowmeter), while FiO(2) decreased more quickly during D(inlet) in CaStar and in 4Vent. PiCO(2) resulted in a lower increase in CaStar during D(source) and D(flowmeter) compared to 4Vent. PetCO(2) in CaStar increases more slowly compared to 4Vent during D(source) and more slowly compared to the other two helmets during D(flowmeter). During D(inlet) similar degrees of CO(2) rebreathing and PetCO(2) were recorded among all the helmets. To minimize CO(2) rebreathing during disconnection of the fresh gas supply while performing helmet CPAP, it is desirable to utilize large helmets with a large anti-suffocation valve. Monitoring and alarm systems should be employed for safe application of helmet CPAP.

Horses and Zebras: complex cardiac anatomy in a patient with out-of-hospital cardiac arrest

This case report describes a woman presenting after out-of-hospital cardiac arrest with several cardiac anomalies, including a form fruste of Ebstein's anomaly complicated by a large tricuspid valve vegetation. On autopsy, she proved to have unstable plaques in epicardial vessels that likely caused arrhythmic sudden cardiac death, a reminder that even in the presence of rare anomalies, common things are common.

Character of Shell Beds Flanking Herod Point Shoal, Southeastern Long Island Sound, New York

Abstract High biogenic productivity, strong tidal currents, shoal topography, and short transport distances combine to favor shell-bed formation along the lower flanks of a cape-associated shoal off Herod Point on Long Island, New York. This shell bed has a densely packed, clast-supported fabric composed largely of undegraded surf clam (Spisula solidissima) valves. It is widest along the central part of the western flank of the shoal where topographic gradients are steep and a stronger flood tide results in residual flow. The bed is narrower and thinner toward the landward margins where currents are too weak to transport larger valves and topographic gradients are gentle, limiting bed-load transport mechanisms by which the shells are concentrated. Reconnaissance mapping off Roanoke Point suggests that shell beds are also present at the other cape-associated shoals off northeastern Long Island, where relatively similar geomorphic and oceanographic conditions exist. These shell beds are important to the Lon...

Initial experience of mitral valve repair using the Carpentier-Edwards Physio II annuloplasty ring

The Carpentier-Edwards (CE) Physio II ring is a new prosthetic ring designed to accommodate the changing pathology seen in the spectrum of degenerative valve disease, particularly the larger anterior leaflet in repair of the Barlow valve. The aim of our study was to assess the safety and efficacy of mitral valve (MV) repair with the CE Physio II ring. Between April 2009 and March 2010, 100 patients underwent MV repair using the Physio II ring. Median age of patients was 70 years (54-85 years). The left ventricle (LV) was moderately (30-50%; n=21) or severely (<30%; n=6) impaired in 27 patients preoperatively. Mitral regurgitation (MR) was due to degenerative disease in 87 patients (bileaflet prolapse: 34 patients). Mean logistic EuroSCORE was 10.07 ± 8.9 and mean follow-up was 6.3 ± 2.4 months. Seventeen patients were non-elective (eight emergencies), five were re-do operations and 23 Maze ± pulmonary vein isolations, and 14 tricuspid annuloplasties were performed. Neo-chordae were inserted in 50 patients (50%), whereas sliding annuloplasty was performed only in three patients. The median ring size was 32 mm (range 26-40 mm). On-table trans-oesophageal echocardiography (TOE) showed trivial/no MR in 87 patients, and mild in 13 patients, and there were no cases of systolic anterior motion (SAM). There were two re-explorations for bleeding and two patients required haemofiltration. There were no strokes or deep sternal wound infections (DSWIs). There was one hospital death (1%). At discharge, mean left ventricular end-diastolic (LVEDD) was 4.8 ± 0.7 cm compared with 5.5 ± 0.8 cm preoperatively (p=0.03) and mean left ventricular end-systolic (LVESD) was 3.3 ± 0.5 cm as compared with 3.6 ± 0.8 preoperatively (p=0.4). There was no MR in 87 patients and mild MR in 13 patients. The mean mitral valve area (MVA) was 2.8 ± 0.7 cm(2). The mean systolic pulmonary artery pressure (SPAP) was 26.6 ± 7.3 mmHg as compared with 50.9 ± 17.2 mmHg preoperatively (p=0.02). During follow-up, there were no thrombo-embolic complications, re-operation, endocarditis or deaths. MV repair with the Physio II ring has excellent short-term results, including subgroups with large anterior mitral valve leaflet (AMVL). Moreover, the dimensional ratios of the ring may allow it to be used for MV repair for degenerative MV disease, irrespective of anterior leaflet size.

Percutaneous Transcatheter Closure of a Paravalvular Leak in a 20-Month Old Child

A 20-month-old boy was referred to the cardiac catheterization laboratory for closure of a large prosthetic mitral valve paravalvular leak. At birth, the boy had an unbalanced atrioventricular septal defect with borderline hypoplasia of the mitral component of the common atrioventricular valve and the left ventricle. At the age of 3 months, the boy underwent complete (two-ventricle) repair. The intraoperative findings included deficient left-sided atrioventricular valve tissue. As a result of the surgical septation, the coronary sinus ostium was located in the left atrium. The boy initially did well, but 6 weeks after his initial surgery, progressive and severe mitral regurgitation developed, necessitating mitral valve replacement with a 19-mm St. Jude prosthetic valve in the supraannular position. A small (posteromedial) paravalvular prosthetic mitral leak was noted approximately 6 months after surgery. This leak became progressively worse, resulting in moderate to severe functional mitral regurgitation and worsening left ventricular dilation. A dilated structure posterior to the left atrioventricular groove also was noted to be expanding. This structure was interpreted by echocardiography as an aneurysm of the coronary sinus. Three-dimensional (3D) echocardiography helped to define the anatomy of the leak (Fig. 1a/Movie 1a in supplementry material). At the age of 20 months, the boy was referred for cardiac catheterization with planned closure of the leak.

The Design of Giant Magnetostrictive Flow Valve and its COMSOL Simulation

By combining magnetostrictive actuator with flow valve directly, the flow was precisely controlled due to magnetic materials’ properties of fast response (less than 1μs)and large magnetostrictive strain (up to 1500ppm). The structure was designed based on this theory, and the flow - displacement model of valve was established by analyzing the size of the valve opening in different incentive current. The flow field was analyzed through multi-physics analysis software COMSOL. Simulation results showed that, the continuous adjustment and precision control were realized in a certain range of flow in the valve. Therefore, it could not only adjust the flow in micro amount directly, but also can be a pilot valve for high frequency precision large flow valve.

Clinical Summaries

Clinical Summaries