WorldWideScience

Sample records for artificial heart valves

  1. Computed Flow Through An Artificial Heart Valve

    Science.gov (United States)

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

    1994-01-01

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

  2. Computed Flow Through An Artificial Heart And Valve

    Science.gov (United States)

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

    1994-01-01

    NASA technical memorandum discusses computations of flow of blood through artificial heart and through tilting-disk artificial heart valve. Represents further progress in research described in "Numerical Simulation of Flow Through an Artificial Heart" (ARC-12478). One purpose of research to exploit advanced techniques of computational fluid dynamics and capabilities of supercomputers to gain understanding of complicated internal flows of viscous, essentially incompressible fluids like blood. Another to use understanding to design better artificial hearts and valves.

  3. Anticoagulation property and security of artificial heart valve material

    Institute of Scientific and Technical Information of China (English)

    WANG; Xianghui; LIU; Xianghuai; ZHANG; Feng; LI; Changron

    2005-01-01

    Heart valve diseases threaten human health. One reliable way to save lives of such patients is to replace the pathologically changed heart valves by artificial ones. Over 2 million patients have received LTI-carbon heart valve's implantation. However, the thrombosis after the implantation is one of the difficulties that need to be solved. In order to improve the blood compatibility and security of mechanical heart valves, ion beam technology was used to modify the surface properties of the materials. The investigation results have been summarized in this paper.

  4. Radiological symptoms of the disfunction of artificial heart valves

    International Nuclear Information System (INIS)

    The possible causes of the disfunction of artificial valves are detailed. Routine X-ray examinations of the chest only rarely reveal direct signs of disfunction, but the haemodynamic alterations (dilated heart chambers, or veins) must be considred as important indirect signs. The characteristics and possibly the cause of the valve insufficience can be analyzed on the basis of kino- and spot radiograms. The symptoms observed by these methods are reported in detail. (L.E.)

  5. PIV Measurements of Flows in Artificial Heart Valves

    Science.gov (United States)

    Kaminsky, Radoslav; Kallweit, Stephan; Rossi, Massimiliano; Morbiducci, Umberto; Scalise, Lorenzo; Verdonck, Pascal; Tomasini, Enrico Primo

    Through several decades many different models of prosthetic artificial heart valves (PHV) have been designed and optimized in order to enhance hemodynamic properties. These properties are not only material dependent but the major influence results from the mechanical assembly of the particular PHV. For the experimental assessment of the flow through such PHVs particle image velocimetry (PIV) is already an accepted method [1] due to its noninvasive optical approach and accuracy. Here, we present various modifications of PIV in order to explain, compare and realize which method is the most suitable for the quantification of such flows. The choice of the experimental procedure for testing the PHVs is strongly dependent on the optical access of the designed in-vitro testing loops simulating the human heart and vascular system. The hardware demand and its configuration for, e.g., stereoscopic PIV is much more complex than standard 2D PIV, therefore the conditions and design of the testing loop have to be realized to allow the desired flow measurement. The flow in heart valves as an unsteady periodically generated flow, can be obtained by averaged phaselocked or measurements with high temporal. The properties, advantages and drawbacks of specific PIV techniques to visualize the flow behind a PHV will be discussed.

  6. A patient with four artificial heart valves after ergotamine therapy

    OpenAIRE

    Bijl, M.; Galema, T. W.; Van Herwerden, L. A.; Kofflard, M.J.M.; Breuls, P.N.W.M.; van de Brink, R.B.A.

    2006-01-01

    A 67-year-old female was evaluated in the out-patient clinic because of shortness of breath on exertion and regular spells of fever. She had been taking ergotamine tartrate to treat migraine for more than 30 years. The patient had undergone aortic-valve replacement for aortic insufficiency three years before. On echocardiographic evaluation, severe retraction and insufficiency of the remaining native heart valves was demonstrated. Endocarditis and carcinoid syndrome were excluded. The mitral,...

  7. Heart valve surgery

    Science.gov (United States)

    Valve replacement; Valve repair; Heart valve prosthesis; Mechanical valves, Prosthetic valves ... made materials, such as metal (stainless steel or titanium) or ceramic. These valves last the longest, but ...

  8. Research on micro-structure and hemo-compatibility of the artificial heart valve surface

    Science.gov (United States)

    Ye, Xia; Shao, Yun-liang; Zhou, Ming; Li, Jian; Cai, Lan

    2009-04-01

    In order to seek the method to improve the hemo-compatibility of artificial mechanical heart valve, the surface of rabbit's heart valve was observed using the scanning electron microscopy (SEM). The results showed that the dual-scale structure which consists of cobblestones-like structure of 8 μm in underside diameter and 3 μm in height, and the fine cilia of about 150 nm in diameter, was helpful to the hemo-compatibility of the heart valve. Therefore, the polydimethylsiloxane (PDMS) surface with hierarchical micro-structure was fabricated using femtosecond laser fabrication technique and soft lithography. At the same time, the tests of apparent contact angle and platelet adhesion on both smooth and textured PDMS surfaces were carried out to study their wettability and hemo-compatibility. The results demonstrated that the surface with textured structure displayed more excellent wettabililty and anti-coagulation property than that of smooth surface. The apparent contact angle of textured surface enhanced from 113.1° to 163.6° and the amount of adsorbed platelet on such surface was fewer, no distortion and no activation were found.

  9. Research on micro-structure and hemo-compatibility of the artificial heart valve surface

    International Nuclear Information System (INIS)

    In order to seek the method to improve the hemo-compatibility of artificial mechanical heart valve, the surface of rabbit's heart valve was observed using the scanning electron microscopy (SEM). The results showed that the dual-scale structure which consists of cobblestones-like structure of 8 μm in underside diameter and 3 μm in height, and the fine cilia of about 150 nm in diameter, was helpful to the hemo-compatibility of the heart valve. Therefore, the polydimethylsiloxane (PDMS) surface with hierarchical micro-structure was fabricated using femtosecond laser fabrication technique and soft lithography. At the same time, the tests of apparent contact angle and platelet adhesion on both smooth and textured PDMS surfaces were carried out to study their wettability and hemo-compatibility. The results demonstrated that the surface with textured structure displayed more excellent wettabililty and anti-coagulation property than that of smooth surface. The apparent contact angle of textured surface enhanced from 113.1 deg. to 163.6 deg. and the amount of adsorbed platelet on such surface was fewer, no distortion and no activation were found.

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

    Science.gov (United States)

    Hedayat, Mohammadali; Asgharzadeh, Hafez; Borazjani, Iman

    2015-11-01

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

  11. 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 ...

  12. Surface modification of polyurethane films by plasma and ultraviolet light to improve haemocompatibility for artificial heart valves

    OpenAIRE

    Alves, P.; Cardoso, R; Correia, T. R.; Antunes, B. P.; Correia, I. J.; Ferreira, P.

    2014-01-01

    Prosthetic cardiac valves implantation is a common procedure used to treat heart valve diseases. Although there are different prostheses already available in the market (either mechanical or bioprosthetic), their use presents several problems, specifically concerning thrombogenicity and structural failure. Recently, some progresses have been achieved in developing heart valves based on synthetic materials with special emphasis in polymers. Among them, polyurethanes are one of the most commonl...

  13. [Mineralization of heart valves].

    Science.gov (United States)

    Pawlikowski, M; Pfitzner, R

    1992-01-01

    Mineralization (calcification) of heart valves (mitral, aortic and aortic bioprosthesis) have been analyzed using; histology, x-ray diffraction, infrared spectroscopy, scanning microscopy, atomic absorption and electron microprobe. Obtained results showed the presence of two type of mineralization. First type is represented by grains composed of hydroxyapatite containing admixture of carbonates. This mineralization is seen macroscopically. Second type of mineralization is possible to determine only using chemical methods. It is represented by biological structures containing amount of Ca, P and other elements higher then normal heart valves. This second type of the mineralization conducts to the changes of physical features of the tissue. Both types of calcification develops because of the defects of atomic structure of biological components of heart valves (mainly collagen). These defects show the presence of free atomic bindings i.e. electric potential. Because of this, they are able to react with surrounding free joints, starting calcification. Defects of biological structures of heart valves are the results of infections, mechanical destruction of the valves etc. Calcification may be stopped on different stages of its development: or as secret calcification or may pass to the stage seen as apatite grains. PMID:1342999

  14. What Is Heart Valve Disease?

    Science.gov (United States)

    ... heart work harder and affect its ability to pump blood. Overview How the Heart Valves Work At the ... into the atria. As the ventricles contract, they pump blood through the pulmonary and aortic valves. The pulmonary ...

  15. Advancements in artificial heart valve disks using nano-sized thin films deposited by CVD and sol-gel techniques

    International Nuclear Information System (INIS)

    Pyrolytic carbon (PyC) is widely used in manufacturing commercial artificial heart valve disks (HVD). Although, PyC is commonly used in HVD, it is not the best material for this application since its blood compatibility is not ideal for prolonged clinical use. As a result thrombosis often occurs and the patients are required to take anti- coagulation drugs on a regular basis in order to minimise the formation of thrombosis. However, the anti-coagulation therapy gives rise to some detrimental side effects in patients. Therefore, it is extremely urgent that newer and more technically advanced materials with better surface and bulk properties are developed. In this paper, we report the mechanical properties of PyC-HVD, namely, strength, wear resistance and coefficient of friction. The strength of the material was assessed using Brinell indentation tests. Furthermore, wear resistance and the coefficient of friction values were obtained from the pin-on-disk testing. The micro-structural properties of PyC were characterized using XRD, Raman spectroscopy and SEM analysis. Also, in this paper we report the preparation of free standing nanocrystalline diamond films (FSND) using the time-modulated chemical vapor deposition (TMCVD) process. Furthermore, the sol-gel technique was used to uniformly coat PyC-HVD with dense, nanocrystalline-titanium oxide (nc-TiO/sub 2/) coatings. The as-grown nc-TiO/sub 2/ coatings were characterized for microstructure using SEM and XRD analysis. (author)

  16. Transcatheter Aortic Heart Valve Thrombosis

    DEFF Research Database (Denmark)

    Hansson, Nicolaj C; Grove, Erik L; Andersen, Henning R;

    2016-01-01

    BACKGROUND: There is increasing focus on transcatheter heart valve (THV) thrombosis. However, there are limited data on incidence, clinical implications and predisposing factors of THV thrombosis following transcatheter aortic valve replacement (TAVR). OBJECTIVES: We assessed the incidence...

  17. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    Kalyani Nair; C V Muraleedharan; G S Bhuvaneshwar

    2003-06-01

    Artificial heart valves are engineered devices used for replacing diseased or damaged natural valves of the heart. Most commonly used for replacement are mechanical heart valves and biological valves. This paper briefly outlines the evolution, designs employed, materials being used,. and important factors that affect the performance of mechanical heart valves. The clinical performance of mechanical heart valves is also addressed. Efforts made in India in the development of mechanical heart valves are also discussed.

  18. What Causes Heart Valve Disease?

    Science.gov (United States)

    ... other infections with strep bacteria that progress to rheumatic fever can cause heart valve disease. When the body tries to fight the strep ... you feel better before the medicine is gone. Heart valve disease caused by rheumatic fever mainly affects older adults who had strep ...

  19. Telocytes in human heart valves

    Science.gov (United States)

    Yang, Yang; Sun, Wei; Wu, Sean M; Xiao, Junjie; Kong, Xiangqing

    2014-01-01

    Valve interstitial cells (VICs) are responsible for maintaining the structural integrity and dynamic behaviour of the valve. Telocytes (TCs), a peculiar type of interstitial cells, have been recently identified by Popescu*s group in epicardium, myocardium and endocardium (visit http://www.telocytes.com). The presence of TCs has been identified in atria, ventricles and many other tissues and organ, but not yet in heart valves. We used transmission electron microscopy and immunofluorescence methods (double labelling for CD34 and c-kit, or vimentin, or PDGF Receptor-β) to provide evidence for the existence of TCs in human heart valves, including mitral valve, tricuspid valve and aortic valve. TCs are found in both apex and base of heart valves, with a similar density of 27–28 cells/mm2 in mitral valve, tricuspid valve and aortic valve. Since TCs are known for the participation in regeneration or repair biological processes, it remains to be determined how TCs contributes to the valve attempts to re-establish normal structure and function following injury, especially a complex junction was found between TCs and a putative stem (progenitor) cell. PMID:24674389

  20. How Is Heart Valve Disease Treated?

    Science.gov (United States)

    ... is called a valve-in-valve procedure. Heart-Healthy Lifestyle Changes to Treat Other Related Heart Conditions To ... your doctor may advise you to make heart-healthy lifestyle changes, such as: Heart-healthy eating Aiming for ...

  1. Telocytes in human heart valves

    OpenAIRE

    Yang, Yang; Sun, Wei; Wu, Sean M; Xiao, Junjie; Kong, Xiangqing

    2014-01-01

    Valve interstitial cells (VICs) are responsible for maintaining the structural integrity and dynamic behaviour of the valve. Telocytes (TCs), a peculiar type of interstitial cells, have been recently identified by Popescu*s group in epicardium, myocardium and endocardium (visit http://www.telocytes.com). The presence of TCs has been identified in atria, ventricles and many other tissues and organ, but not yet in heart valves. We used transmission electron microscopy and immunofluorescence met...

  2. Surface modification of polyurethane films by plasma and ultraviolet light to improve haemocompatibility for artificial heart valves.

    Science.gov (United States)

    Alves, P; Cardoso, R; Correia, T R; Antunes, B P; Correia, I J; Ferreira, P

    2014-01-01

    Prosthetic cardiac valves implantation is a common procedure used to treat heart valve diseases. Although there are different prostheses already available in the market (either mechanical or bioprosthetic), their use presents several problems, specifically concerning thrombogenicity and structural failure. Recently, some progresses have been achieved in developing heart valves based on synthetic materials with special emphasis in polymers. Among them, polyurethanes are one of the most commonly used for the production of these devices. Herein, Elastollan(®)1180A50, a thermoplastic polyurethane (TPU), was used to formulate films whose surfaces were modified by grafting 2-hydroxyethylmethacrylate (HEMA) either by ultra-violet (UV) or by plasma treatment. All films were analyzed before and after grafting. X-ray photoelectron spectroscopy (XPS) measurements were used to evaluate TPU surfaces functionalization. HEMA grafting was confirmed by the increase of the hydroxyl (OH) groups' concentration at the surface of the films. Atomic force microscopy (AFM) analysis was done to evaluate the surface topography of the biomaterials. Results showed that the roughness of the surface decreased when HEMA was grafted, especially for plasma treated samples. After grafting the films' hydrophilicity was improved, as well as the polar component of the surface energy, by 15-30%. Hydrophobic recovery studies using milli Q water or PBS were also performed to characterize the stability of the modified surface, showing that the films maintained their surface properties along time. Furthermore, blood-contact tests were performed to evaluate haemolytic and thrombogenic potential. The results obtained for HEMA grafted surfaces, using plasma treatment, confirmed biomaterials biocompatibility and low thrombogenicity. Finally, the cytotoxicity and antibacterial activity of the materials was assessed through in vitro assays for both modified films. The obtained results showed enhanced

  3. Tissue-engineered heart valves

    Czech Academy of Sciences Publication Activity Database

    Filová, Elena; Straka, František; Miřejovský, T.; Mašín, J.; Bačáková, Lucie

    2009-01-01

    Roč. 58, Suppl.2 (2009), S141-S158. ISSN 0862-8408 R&D Projects: GA MŠk(CZ) 1M0510; GA AV ČR(CZ) 1QS500110564 Institutional research plan: CEZ:AV0Z50110509 Keywords : bioarteficial heart valve * valve interstitial cells * pulse flow bioreactor Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.430, year: 2009

  4. Prosthetic heart valves: Objective Performance Criteria versus randomized clinical trial.

    Science.gov (United States)

    Grunkemeier, Gary L; Jin, Ruyun; Starr, Albert

    2006-09-01

    The current Food and Drug Administration (FDA) heart valve guidance document uses an objective performance criteria (OPC) methodology to evaluate the clinical performance of prosthetic heart valves. OPC are essentially historical controls, but they have turned out to be an adequate, and perhaps optimal, study design in this situation. Heart valves have a simple open-and-close mechanism, device effectiveness is easy to document, and the common complications (thromboembolism, thrombosis, bleeding, leak, and infection) are well known and easily detected. Thus, randomized clinical trials (RCTs) have not been deemed necessary for the regulatory approval of prosthetic heart valves. The OPC are derived from the average complication rates of all approved heart valves. Studies based on OPC have been shown to work well; many different valve models have gained FDA market approval based on this methodology. Although heart valve RCTs are not required by the FDA, they have been done to compare valves or treatment regimens after approval. Recently, the Artificial Valve Endocarditis Reduction Trial (AVERT) was designed to compare a new Silzone sewing ring, designed to reduce infection, with the Standard sewing ring on a St. Jude Medical heart valve. This was the largest heart valve RCT ever proposed (4,400 valve patients, followed for as long as 4 years), but it was stopped prematurely because of a high leak rate associated with the Silzone valve. Examining the results showed that a much smaller, OPC-based study with 800 patient-years would have been sufficient to disclose this complication of the Silzone valve. PMID:16928482

  5. How Is Heart Valve Disease Diagnosed?

    Science.gov (United States)

    ... assess the severity of your heart valve disease. Cardiac MRI Cardiac MRI uses a powerful magnet and radio waves to make detailed images of your heart. A cardiac MRI image can confirm information about valve defects or ...

  6. Heart valve surgery - discharge

    Science.gov (United States)

    ... the hospital. You may have been in the intensive care unit some of the time, in the hospital, you ... dentist. Tell all of your providers (dentist, doctors, nurses, or nurse practitioners) about your heart problem. You ...

  7. Approaches to the artificial heart. Invited speaker.

    Science.gov (United States)

    Pierce, W S; Myers, J L; Donachy, J H; Rosenberg, G; Landis, D L; Prophet, G A; Snyder, A J

    1981-08-01

    Over the last two decades, the implantable artificial heart has evolved from an idea to a device capable of completely supporting the circulation for periods now exceeding 5 months. Although initial animal studies were limited by thromboembolism and device breakage, the usual causes of death in experimental animals are now infection, atrioventricular valve obstruction, elastomer bladder calcification, or inadequate cardiac output because of the relatively rapid growth of the young calves. As a result of the bulky nature of the energy converter and the substantial risk of infection with large diameter percutaneous tubes, clinical use of their air-powered artificial hearts will be limited to patients who are awaiting or being prepared for heart transplantation. Artificial hearts with implanted energy converters are being developed for permanent heart replacement. These devices require well-designed, durable mechanical components and sophisticated control systems. Although initial designs centered around thermal engines powered by a completely implantable nuclear energy source, the excessive cost and potential dangers have shifted the focus away from the nuclear system. Several electrically driven artificial hearts, based on samarium-cobalt magnet brushless direct-current motors, are now undergoing bench testing and will be ready for long-term animal studies within 2 years. This research will culminate with the availability of an "off-the-shelf" electrically powered artificial heart for use in patients with a wide range of nonrepairable forms of end-stage heart disease. PMID:7256534

  8. An electric artificial heart for clinical use.

    Science.gov (United States)

    Pierce, W S; Rosenberg, G; Snyder, A J; Pae, W E; Donachy, J H; Waldhausen, J A

    1990-09-01

    Advances in microelectronics, high-strength magnets, and control system design now make replacement of the heart using an implantable, electrically powered pump feasible. The device described herein is a compact, dual pusher plate unit with valved polyurethane sac-type ventricles positioned at either end. The power unit consists of a small, brushless direct current motor and a motion translator. A microprocessor control system is used to regulate heart beat rate and provide left-right output balance. Bench studies lasting for as long as 1 year have been performed. Heart replacement with the electric heart has been performed in 18 calves since 1984. The longest survivor lived for more than 7 months. Among the causes of termination were component failure, thromboembolic complications, and bleeding. No major problem has been identified that precludes prolonged use of the electric heart. In the future the patient with end-stage heart disease will have an electric artificial heart as one therapeutic option. PMID:2396885

  9. Surface Modification using Plasma treatments and Adhesion Peptide for Durable Tissue-Engineered Heart Valves

    International Nuclear Information System (INIS)

    Artificial heart valves are used in valvular heart diseases, but these valves have disadvantages that they cannot grow, repair and remodel. In current study, the strategies to development of in vitro cultured functional tissue by tissue engineering is available to heart valve disease. In the point of using viable autolougous cells, tissue engineered heart valves have some advantage to include that they can repair, remodel, and grow. Because heart valve is placed under the strong shear stress condition by pumping of heart, the durability of tissue-engineered heart valves is now questionable. The purpose of the study is to evaluate of the durability of tissue engineered heart valve with surface modified scaffolds under hemodynamic conditions

  10. Mechanism of artificial heart

    CERN Document Server

    Yamane, Takashi

    2016-01-01

    This book first describes medical devices in relation to regenerative medicine before turning to a more specific topic: artificial heart technologies. Not only the pump mechanisms but also the bearing, motor mechanisms, and materials are described, including expert information. Design methods are described to enhance hemocompatibility: main concerns are reduction of blood cell damage and protein break, as well as prevention of blood clotting. Regulatory science from R&D to clinical trials is also discussed to verify the safety and efficacy of the devices.

  11. Heart Valve Disease among Patients with Hyperprolactinaemia

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  12. The radiology of prosthetic heart valves

    International Nuclear Information System (INIS)

    The development of prosthetic heart valves in the late 1950s ushered in a new era in the treatment of heart disease. The radiologist has an important role to play preoperatively in the diagnosis of valvular heart disease. Radiology is valuable in identification of the implanted prosthetic valve and recognition of complications associated with valve implantation. Radiologists must be familiar with the imaging techniques best suited to evaluate the function of the valve prosthesis in question. In this chapter the authors discuss the radiographic approach to the evaluation of the status of patients for valve replacement and the imaging problems peculiar to the types of valves in current use. The relative value of plain-film radiography, fluoroscopy, videorecording and cinerecording, and aortography is addressed, as well as the potential value of magnetic resonance imaging and subsecond dynamic computed tomography

  13. Human Mesenchymal Stem Cells Reendothelialize Porcine Heart Valve Scaffolds: Novel Perspectives in Heart Valve Tissue Engineering

    OpenAIRE

    Lanuti, Paola; Serafini, Francesco; Pierdomenico, Laura; Simeone, Pasquale; Bologna, Giuseppina; Ercolino, Eva; Di Silvestre, Sara; Guarnieri, Simone; Canosa, Carlo; Impicciatore, Gianna Gabriella; Chiarini, Stella; Magnacca, Francesco; Mariggiò, Maria Addolorata; Pandolfi, Assunta; Marchisio, Marco

    2015-01-01

    Abstract Heart valve diseases are usually treated by surgical intervention addressed for the replacement of the damaged valve with a biosynthetic or mechanical prosthesis. Although this approach guarantees a good quality of life for patients, it is not free from drawbacks (structural deterioration, nonstructural dysfunction, and reintervention). To overcome these limitations, the heart valve tissue engineering (HVTE) is developing new strategies to synthesize novel types of valve substitutes,...

  14. Mathematical problems in modeling artificial heart

    Directory of Open Access Journals (Sweden)

    Ahmed N. U.

    1995-01-01

    Full Text Available In this paper we discuss some problems arising in mathematical modeling of artificial hearts. The hydrodynamics of blood flow in an artificial heart chamber is governed by the Navier-Stokes equation, coupled with an equation of hyperbolic type subject to moving boundary conditions. The flow is induced by the motion of a diaphragm (membrane inside the heart chamber attached to a part of the boundary and driven by a compressor (pusher plate. On one side of the diaphragm is the blood and on the other side is the compressor fluid. For a complete mathematical model it is necessary to write the equation of motion of the diaphragm and all the dynamic couplings that exist between its position, velocity and the blood flow in the heart chamber. This gives rise to a system of coupled nonlinear partial differential equations; the Navier-Stokes equation being of parabolic type and the equation for the membrane being of hyperbolic type. The system is completed by introducing all the necessary static and dynamic boundary conditions. The ultimate objective is to control the flow pattern so as to minimize hemolysis (damage to red blood cells by optimal choice of geometry, and by optimal control of the membrane for a given geometry. The other clinical problems, such as compatibility of the material used in the construction of the heart chamber, and the membrane, are not considered in this paper. Also the dynamics of the valve is not considered here, though it is also an important element in the overall design of an artificial heart. We hope to model the valve dynamics in later paper.

  15. Artificial heart for humanoid robot

    Science.gov (United States)

    Potnuru, Akshay; Wu, Lianjun; Tadesse, Yonas

    2014-03-01

    A soft robotic device inspired by the pumping action of a biological heart is presented in this study. Developing artificial heart to a humanoid robot enables us to make a better biomedical device for ultimate use in humans. As technology continues to become more advanced, the methods in which we implement high performance and biomimetic artificial organs is getting nearer each day. In this paper, we present the design and development of a soft artificial heart that can be used in a humanoid robot and simulate the functions of a human heart using shape memory alloy technology. The robotic heart is designed to pump a blood-like fluid to parts of the robot such as the face to simulate someone blushing or when someone is angry by the use of elastomeric substrates and certain features for the transport of fluids.

  16. Heart Valve Surgery Recovery and Follow Up

    Science.gov (United States)

    ... Stroke More Heart Valve Surgery Recovery and Follow Up Updated:May 27,2016 Surgery Recovery Checklist English | ... self-care and are soon encouraged to get up, to breathe deeply, and to resume eating, drinking ...

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

    Science.gov (United States)

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

    2014-01-01

    Today, the quality of mechanical heart valves is quite high, and implantation has become a routine clinical procedure with a low operative mortality (valves are thought of having higher cavitation potential than bileaflet valves due to higher closing velocities. However, the thromboembolic potential seems to be the same. Further studies are therefore needed to investigate the cavitation potential of bileaflet valves in vivo. The post processing of HFPF have shown difficulties when applied on bileaflet vavles due to asynchronous closure of the two leaflets. The aim of this study was therefore to isolate the pressure signature from each leaflet closure and perform cavitation analyses on each component. Six patients were included in the study (St. Jude Medical (n=3) and CarboMedics (n=3); all aortic bileaflet mechanical heart valves). HFPFs were recorded intraoperatively through a hydrophone at the aortic root. The pressure signature relating to the first and second leaflet closure was isolated and cavitation parameters were calculated (RMS after 50 kHz highpass filtering and signal energy). Data were averaged over 30 heart cycles. For all patients both the RMS value and signal energy of the second leaflet closure were higher than for the first leaflet closure. This indicates that the second leaflet closure is most prone to cause cavitation. Therefore, quantifying cavitation based on the HFPF related to the second leaflet closure may suggest that the cavitation potential for bileaflet valves in vivo may be higher than previous studies have suggested. PMID:25571278

  18. 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.

  19. Magnetic resonance imaging in patients with heart valve prostheses

    International Nuclear Information System (INIS)

    Artifical valve prostheses are often regarded as a contraindication for magnetic resonance imaging (MRI), although preliminary in vitro studies suggested, that patients with these metallic implants might safely undergo MR examination. This study reports on the experience with a group of 89 patients with 100 heart valve prostheses who were examined by spin-echo MR and gradient-echo MR. MR examination was performed in all patients without complications. The spin-echo sequence showed advantages in the depiction of anatomical structures like paravalvular abcesses. Anatomical structures adjacent to the artificial valve were clearly visivle and the metal components of the valves showes no or only small artifacts. Artifacts were accentuated when using gradient-echo sequences. Gradient-echo sequences provided valuable information regarding the presence of valvular insufficiency. Physiological valvular regurgitation was easy to differentiate from pathological paravalvular or transvalvular regurgitation. These results demonstrate that patients with artificial valve prostheses can be imaged by MR without risk and that prosthesis-induced artifacts do no interfere with image interpretation. (orig.)

  20. 21 CFR 870.3925 - Replacement heart valve.

    Science.gov (United States)

    2010-04-01

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

  1. Effect of comprehensive cardiac rehabilitation after heart valve surgery (CopenHeartVR)

    DEFF Research Database (Denmark)

    Sibilitz, Kirstine Laerum; Berg, Selina Kikkenborg; Hansen, Tina Birgitte;

    2013-01-01

    Heart valve diseases are common with an estimated prevalence of 2.5% in the Western world. The number is rising due to an ageing population. Once symptomatic, heart valve diseases are potentially lethal, and heavily influence daily living and quality of life. Surgical treatment, either valve repl...... hospitalisation and healthcare costs after heart valve surgery....

  2. DONOR HEART VALVES RECONSTRUCTION BEFORE TRANSPLANTATION

    Directory of Open Access Journals (Sweden)

    S. V. Gautier

    2013-01-01

    Full Text Available Aim of study. The demonstration of our own experience in heart transplantation after valve reconstruction. Methods and results. From May 2012 to March 2013 3 mitral valve annuloplasties were performed to recipi- ents, requiring urgent HT and having extremely unfavorable prognosis of survival without HT. The recipients were classified as United Network for Organ Sharing (UNOS IB, and all of them were on inotropic support. In one case, HT was performed after reconstruction of rheumatic mitral stenosis, in two other cases – after dege- nerative mitral regurgitation. The technical aspects are reviewed of ex-vivo mitral and tricuspid valves repair with concomitant heart transplantation. All patients were discharged from the hospital having excellent postope- rative recovery. Conclusion. Taking into consideration the demonstrated satisfactory result of surveillance and presence of significant experience in performing of reconstructive valve surgery among no-HT cardiosurgical patients, an increase in the pool of suitable donor organs is expected due to the liberalization of the selection criteria and the possibility of the innovative valve reconstruction procedures ex vivo. 

  3. Human Mesenchymal Stem Cells Reendothelialize Porcine Heart Valve Scaffolds: Novel Perspectives in Heart Valve Tissue Engineering

    Science.gov (United States)

    Lanuti, Paola; Serafini, Francesco; Pierdomenico, Laura; Simeone, Pasquale; Bologna, Giuseppina; Ercolino, Eva; Di Silvestre, Sara; Guarnieri, Simone; Canosa, Carlo; Impicciatore, Gianna Gabriella; Chiarini, Stella; Magnacca, Francesco; Mariggiò, Maria Addolorata; Pandolfi, Assunta; Marchisio, Marco; Di Giammarco, Gabriele; Miscia, Sebastiano

    2015-01-01

    Abstract Heart valve diseases are usually treated by surgical intervention addressed for the replacement of the damaged valve with a biosynthetic or mechanical prosthesis. Although this approach guarantees a good quality of life for patients, it is not free from drawbacks (structural deterioration, nonstructural dysfunction, and reintervention). To overcome these limitations, the heart valve tissue engineering (HVTE) is developing new strategies to synthesize novel types of valve substitutes, by identifying efficient sources of both ideal scaffolds and cells. In particular, a natural matrix, able to interact with cellular components, appears to be a suitable solution. On the other hand, the well-known Wharton's jelly mesenchymal stem cells (WJ-MSCs) plasticity, regenerative abilities, and their immunomodulatory capacities make them highly promising for HVTE applications. In the present study, we investigated the possibility to use porcine valve matrix to regenerate in vitro the valve endothelium by WJ-MSCs differentiated along the endothelial lineage, paralleled with human umbilical vein endothelial cells (HUVECs), used as positive control. Here, we were able to successfully decellularize porcine heart valves, which were then recellularized with both differentiated-WJ-MSCs and HUVECs. Data demonstrated that both cell types were able to reconstitute a cellular monolayer. Cells were able to positively interact with the natural matrix and demonstrated the surface expression of typical endothelial markers. Altogether, these data suggest that the interaction between a biological scaffold and WJ-MSCs allows the regeneration of a morphologically well-structured endothelium, opening new perspectives in the field of HVTE. PMID:26309804

  4. Microscopic and ultramicroscopic characteristic of heart valves in human

    OpenAIRE

    Fedoniuk L.; Semeniuk T.; Bodnar E.

    2014-01-01

    Background. Valvular apparatus of the heart is the frequent object of the surgical operations for today. Morphological changes which are happed within valves of the heart at time of cardiac diseases the modern medicine considers on the clinical, instrumental, histological, cytological and ultramicroscopical levels. The cardiac surgeons that make the heart valve replacement using the tissue engineering have the great interest in front of the heart valves. The achievements of the modern medicin...

  5. The surface microstructure of cusps and leaflets in rabbit and mouse heart valves

    Directory of Open Access Journals (Sweden)

    Xia Ye

    2014-05-01

    Full Text Available In this investigation, scanning electron microscopy was used to characterize the microstructure on the surfaces of animal heart valve cusps/leaflets. The results showed that though these surfaces appear smooth to the naked eye, they are actually comprised of a double hierarchical structure consisting of a cobblestone-like microstructure and nano-cilia along with mastoids with a directional arrangement. Such nanostructures could play a very important role in the hemocompatibility characteristics of heart valves. On this basis, the model of the microstructure was constructed and theoretical analysis was used to obtain optimal geometric parameters for the rough surface of artificial valve cusps/leaflets. This model may help improve reconstructive techniques and it may be beneficial in the design and fabrication of valve substitutes or partial substitutes. Namely, the model may help ameliorate heart valve replacement surgery.

  6. Pathogenic Mineralization of Calcium Phosphate on Human Heart Valves

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    When calcium phosphate forms in soft tissues such as blood vessels and heart valves, it causes disease. The abnormal formation of calcium phosphate is called pathogenic mineralization or pathogenic calcification. Cases of rheumatic heart disease (RHD) always occur with fibrotic and calcified tissue of heart valve. In this article, samples taken from calcified human heart valves were studied. The characterization was performed by scanning electronic micrascope, X-ray Diffraction and transmission electron microscopy with selective diffraction patterns. It is found for the first time that calcium phosphate grains existing in the calcified human heart valves contain octacalcium phosphate (OCP).

  7. Heart rate, heart rate variability, and arrhythmias in dogs with myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Rasmussen, Caroline Elisabeth; Falk, Bo Torkel; Zois, Nora Elisabeth; Moesgaard, Sophia Gry; Häggström, J.; Pedersen, H. D.; Åblad, B.; Nilsen, H. Y.; Olsen, Lisbeth Høier

    2012-01-01

    Autonomic modulation of heart rhythm is thought to influence the pathophysiology of myxomatous mitral valve disease (MMVD).......Autonomic modulation of heart rhythm is thought to influence the pathophysiology of myxomatous mitral valve disease (MMVD)....

  8. Multimodality Imaging Assessment of Prosthetic Heart Valves.

    Science.gov (United States)

    Suchá, Dominika; Symersky, Petr; Tanis, W; Mali, Willem P Th M; Leiner, Tim; van Herwerden, Lex A; Budde, Ricardo P J

    2015-09-01

    Echocardiography and fluoroscopy are the main techniques for prosthetic heart valve (PHV) evaluation, but because of specific limitations they may not identify the morphological substrate or the extent of PHV pathology. Cardiac computed tomography (CT) and magnetic resonance imaging (MRI) have emerged as new potential imaging modalities for valve prostheses. We present an overview of the possibilities and pitfalls of CT and MRI for PHV assessment based on a systematic literature review of all experimental and patient studies. For this, a comprehensive systematic search was performed in PubMed and Embase on March 24, 2015, containing CT/MRI and PHV synonyms. Our final selection yielded 82 articles on surgical valves. CT allowed adequate assessment of most modern PHVs and complemented echocardiography in detecting the obstruction cause (pannus or thrombus), bioprosthesis calcifications, and endocarditis extent (valve dehiscence and pseudoaneurysms). No clear advantage over echocardiography was found for the detection of vegetations or periprosthetic regurgitation. Whereas MRI metal artifacts may preclude direct prosthesis analysis, MRI provided information on PHV-related flow patterns and velocities. MRI demonstrated abnormal asymmetrical flow patterns in PHV obstruction and allowed prosthetic regurgitation assessment. Hence, CT shows great clinical relevance as a complementary imaging tool for the diagnostic work-up of patients with suspected PHV obstruction and endocarditis. MRI shows potential for functional PHV assessment although more studies are required to provide diagnostic reference values to allow discrimination of normal from pathological conditions. PMID:26353926

  9. Microscopic and ultramicroscopic characteristic of heart valves in human

    Directory of Open Access Journals (Sweden)

    Fedoniuk L.

    2014-09-01

    Full Text Available Background. Valvular apparatus of the heart is the frequent object of the surgical operations for today. Morphological changes which are happed within valves of the heart at time of cardiac diseases the modern medicine considers on the clinical, instrumental, histological, cytological and ultramicroscopical levels. The cardiac surgeons that make the heart valve replacement using the tissue engineering have the great interest in front of the heart valves. The achievements of the modern medicine are impossible without the fundamental morphological investigations. Objective. To study the morphological features of the cusps of human heart valves on the light and ultramicroscopic levels. Methods. We have reviewed the structure of cusps of 48 heart valves of adults. It was used a light and electron microscopy which enabled us to study the morphology of cusps of atria-ventricular and ventriculo-vascular heart valves. Results. The data indicate that cusps of heart valves are stratified. Layers of cusps are made of different types of fibrous connective tissues. The spongy layer is made of loose connective tissue, the fibrous layer – dense regular connective tissue, ventricular layer – dense irregular connective tissue. The arrangement of these layers in the cusps of atria-ventricular heart valves (in the direction from atrium toward ventricle is: spongy, fibrous and ventricular. The arrangement of these layers in the cusps of ventricular-vascular heart valves (in the direction from side that is faced to the wall of blood vessel toward the ventricle is: fibrous, spongy, ventricular. Conclusion. The position of data layers within cusp of atria-ventricular valves differs from position of data layers within ventriculo-vascular valves. These changes of tissue localization correlate to haemodynamic conditions during heart cycle. Citation: Fedoniuk L, Semeniuk T, Bodnar E. [Microscopic and ultramicroscopic characteristic of heart valves in human

  10. Total artificial hearts: past, present, and future.

    Science.gov (United States)

    Cohn, William E; Timms, Daniel L; Frazier, O H

    2015-10-01

    A practical artificial heart has been sought for >50 years. An increasing number of people succumb to heart disease each year, but the number of hearts available for transplantation remains small. Early total artificial hearts mimicked the pumping action of the native heart. These positive-displacement pumps could provide adequate haemodynamic support and maintain the human circulation for short periods, but large size and limited durability adversely affected recipients' quality of life. Subsequent research into left ventricular assist devices led to the use of continuous-flow blood pumps with rotating impellers. Researchers have attempted to integrate this technology into modern total artificial hearts with moderate clinical success. The importance of pulsatile circulation remains unclear. Future research is, therefore, needed into positive-displacement and rotary total artificial hearts. PMID:26031698

  11. Tomographic PIV behind a prosthetic heart valve

    Science.gov (United States)

    Hasler, D.; Landolt, A.; Obrist, D.

    2016-05-01

    The instantaneous three-dimensional velocity field past a bioprosthetic heart valve was measured using tomographic particle image velocimetry. Two digital cameras were used together with a mirror setup to record PIV images from four different angles. Measurements were conducted in a transparent silicone phantom with a simplified geometry of the aortic root. The refraction indices of the silicone phantom and the working fluid were matched to minimize optical distortion from the flow field to the cameras. The silicone phantom of the aorta was integrated in a flow loop driven by a piston pump. Measurements were conducted for steady and pulsatile flow conditions. Results of the instantaneous, ensemble and phase-averaged flow field are presented. The three-dimensional velocity field reveals a flow topology, which can be related to features of the aortic valve prosthesis.

  12. Signal processing of Shiley heart valve data for fracture detection

    Energy Technology Data Exchange (ETDEWEB)

    Mullenhoff, C.

    1993-09-01

    Given digital acoustic data emanating from the heart sounds of the beating heart measured from laboratory sheep with implanted Bjoerk-Shiley Convexo-Concave heart valves, it is possible to detect and extract the opening and closing heart beats from the data. Once extracted, spectral or other information can then obtained from the heartbeats and passed on to feature extraction algorithms, neural networks, or pattern recognizers so that the valve condition, either fractured or intact, may be determined.

  13. The development of transcatheter heart valves: opportunities and challenges.

    Science.gov (United States)

    Laske, Tim; Denton, Melissa; Eberhardt, Carol

    2009-01-01

    Although the heart valve market is relatively mature, many patients currently indicated for valve repair or replacement are either undiagnosed, not referred for surgery, or are too sick/unwilling to undergo the required surgery (Table I). To address this unmet clinical need, the medical device industry has undertaken the development of transcatheter heart valves (TCV). These devices are tissue heart valves that can be delivered without open heart surgery and are intended to complement the portfolio of current and future surgical valve products. Several companies have developed novel product designs. Some transcatheter valves are currently available for the aortic and pulmonic positions via European CE mark, and are in clinical trials throughout the United States. PMID:19963953

  14. Heart valve disease: investigation by cardiovascular magnetic resonance

    OpenAIRE

    Myerson Saul G

    2012-01-01

    Abstract Cardiovascular magnetic resonance (CMR) has become a valuable investigative tool in many areas of cardiac medicine. Its value in heart valve disease is less well appreciated however, particularly as echocardiography is a powerful and widely available technique in valve disease. This review highlights the added value that CMR can bring in valve disease, complementing echocardiography in many areas, but it has also become the first-line investigation in some, such as pulmonary valve di...

  15. Prosthetic heart valve selection in women of childbearing age with acquired heart disease: a case report

    OpenAIRE

    Barbarash, Leonid; Rutkovskaya, Natalya; Barbarash, Olga; Odarenko, Yuri; Stasev, Alexander; Uchasova, Evgenya

    2016-01-01

    Background The problem of prosthetic heart valve selection in fertile women with acquired heart defects remains crucial in modern cardiology. Mechanical heart valves require lifelong indirect anticoagulant therapy, which has significant fetal toxicity and is unacceptable for women planning pregnancy. Bioprosthetic heart valves are the best choice for fertile women; however, their durability is limited, and reoperations are required. Case presentation We describe the clinical case of a 21-year...

  16. Auxiliary total artificial heart: A compact electromechanical artificial heart working simultaneously with the natural heart.

    Science.gov (United States)

    Andrade, A; Nicolosi, D; Lucchi, J; Biscegli, J; Arruda, A C; Ohashi, Y; Mueller, J; Tayama, E; Glueck, J; Nosé, Y

    1999-09-01

    Leading international institutions are designing and developing various types of ventricular assist devices (VAD) and total artificial hearts (TAH). Some of the commercially available pulsatile VADs are not readily implantable into the thoracic cavity of smaller size patients because of size limitation. The majority of the TAH dimensions requires the removal of the patients' native heart. A miniaturized artificial heart, the auxiliary total artificial heart (ATAH), is being developed in these authors' laboratories. This device is an electromechanically driven ATAH using a brushless direct current (DC) motor fixed in a center metallic piece. This pusher plate-type ATAH control is based on Frank-Starling's law. The beating frequency is regulated through the change of the left preload, assisting the native heart in obtaining adequate blood flow. With the miniaturization of this pump, the average sized patient can have the surgical implantation procedure in the right thoracic cavity without removing the native heart. The left and right stroke volumes are 35 and 32 ml, respectively. In vitro tests were conducted, and the performance curves demonstrate that the ATAH produces 5 L/min of cardiac output at 180 bpm (10 mmHg of left inlet mean pressure and 100 mm Hg of left outlet mean pressure). Taking into account that this ATAH is working along with the native heart, this output is more than satisfactory for such a device. PMID:10491037

  17. Exercise-based cardiac rehabilitation after heart valve surgery

    DEFF Research Database (Denmark)

    Hansen, T B; Zwisler, Ann-Dorthe; Berg, S K;

    2015-01-01

    BACKGROUND: Owing to a lack of evidence, patients undergoing heart valve surgery have been offered exercise-based cardiac rehabilitation (CR) since 2009 based on recommendations for patients with ischaemic heart disease in Denmark. The aim of this study was to investigate the impact of CR on the...... expensive outpatient visits. Further studies should investigate the benefits of CR to heart valve surgery patients as part of a formal cost-utility analysis....

  18. Pregnancy outcome in women with prosthetic heart valves.

    Science.gov (United States)

    Hall, D R; Olivier, J; Rossouw, G J; Grové, D; Doubell, A F

    2001-03-01

    The pregnancy outcome of 59 pregnancies in 38 women with prosthetic heart valves, managed at a tertiary referral centre from 1989-98 were reviewed. Ten women underwent valve replacement during pregnancy. The main outcome measures were major maternal complications and perinatal outcome. The maternal mortality rate for pregnancies following valve replacement surgery was 6.1%, with a 21% pregnancy loss before viability and a perinatal loss of 8%. Major morbidity in this group was as follows: haemorrhage 29.8%, cardiac failure 12.8%, thromboembolism 8.5%, infective endocarditis 6.4% and valve thrombosis 4.3%. No maternal mortality occurred among those who underwent valve replacement during pregnancy but their perinatal loss was 25%. We conclude that although maternal mortality and morbidity rates in women with prosthetic heart valves who became pregnant were high, the perinatal outcome was good except for women who underwent valve replacement during pregnancy who experienced a high perinatal loss rate. PMID:12521884

  19. Processing of prosthetic heart valve sounds for classification. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.; Jones, H.E.

    1994-04-01

    People with serious heart conditions have had their expected life span extended considerably with the development of the prosthetic heart valve especially with the great strides made in valve design. Even though the designs are extremely reliable, the valves are mechanical and operating continuously over a long period, therefore, structural failures can occur due to fatigue. Measuring heart sounds non-invasively in a noisy environment puts more demands on the signal processing to extract the desired signals from the noise. In this paper the authors discuss acoustical signal processing techniques developed to process noisy heart valve sounds measured by a sensitive, surface contact microphone and used for the eventual classification of the valve.

  20. Comparison of heart valve culture between two Danish endocarditis centres

    DEFF Research Database (Denmark)

    Voldstedlund, Marianne; Fuursted, Kurt; Bruun, Niels Eske;

    2012-01-01

    The degree to which the results of valve culture depend on different laboratory procedures as well as other factors is unknown. The aim of this study was to compare the results of heart valve culture at 2 different endocarditis centres in order to clarify this.......The degree to which the results of valve culture depend on different laboratory procedures as well as other factors is unknown. The aim of this study was to compare the results of heart valve culture at 2 different endocarditis centres in order to clarify this....

  1. Artificial Heart and Self-making

    Science.gov (United States)

    Imachi, Kou

    Artificial heart (AH) study has been started in 1957. After the accomplishments of various difficulties, the AH can become to use clinically as a postcardiotomy cardiac assist or bridge to heart transplantation. However, there remain many obstacles to realize an implantable total artificial heart. The history of AH was the self-making. Although self-making is important in all the experimental sciences, it is the most important factor to develop AH. In this paper, the author would like to introduce the present status of AH and the importance of self-making.

  2. Heart MRI

    Science.gov (United States)

    ... you have: Brain aneurysm clips Certain types of artificial heart valves Heart defibrillator or pacemaker Inner ear (cochlear) implants Kidney disease or dialysis (you may not be able to ... artificial joints Certain types of vascular stents Worked with ...

  3. Classification of heart valve condition using acoustic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Clark, G. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    Prosthetic heart valves and the many great strides in valve design have been responsible for extending the life spans of many people with serious heart conditions. Even though the prosthetic valves are extremely reliable, they are eventually susceptible to long-term fatigue and structural failure effects expected from mechanical devices operating over long periods of time. The purpose of our work is to classify the condition of in vivo Bjork-Shiley Convexo-Concave (BSCC) heart valves by processing acoustic measurements of heart valve sounds. The structural failures of interest for Bscc valves is called single leg separation (SLS). SLS can occur if the outlet strut cracks and separates from the main structure of the valve. We measure acoustic opening and closing sounds (waveforms) using high sensitivity contact microphones on the patient`s thorax. For our analysis, we focus our processing and classification efforts on the opening sounds because they yield direct information about outlet strut condition with minimal distortion caused by energy radiated from the valve disc.

  4. 人工心瓣含硅低温热解炭涂层热处理分析%Analysis of Heat Treatment of Silicon-alloyed Low Temperature Pyrocarbon Coating for Artificial Heart Valves

    Institute of Scientific and Technical Information of China (English)

    喻主路; 张建辉

    2015-01-01

    Silicon-alloyed low temperature pyrocarbon coating for artificial heart valves was deposited by chemical vapor deposition ( CVD ) .The influence of heat treatment on the microstructure and mechanical properties of specimen was studied by X-ray diffraction , scanning electron microscopy , transmission electron microscopy , nanoindentation and dilatometer .The results show that the coating consists of two phases named pyrocarbon(turbostratic graphite-like structure) and β-SiC.After heat treatment the grain size of both become larger, and the carbon(002) planar spacing decreases which means the degree of graphitization of pyrocarbon improved.SEM and TEM show the material consists of spherical particles , and there exists pores among the particles.After heat treatment the pore structure of the material is changed , the number of large pores decreases, the pore distribution is more uniform .The changes in microstructure consequently cause the decrease of nano-hardness and increase of thermal expansion coefficient .%采用化学气相沉积法制备人工心瓣含硅低温热解炭涂层,并进行热处理。利用X射线衍射仪、扫描电子显微镜、透射电子显微镜、纳米压痕仪、热膨胀仪研究了热处理对涂层微观结构和性能的影响。结果表明,涂层包含热解炭(乱层石墨结构)与β-SiC两种物相,热处理后热解炭微晶层间距减小,表明石墨化程度提高,同时β-SiC微晶与热解炭微晶尺寸增大。电镜下材料主要由类球形颗粒组成,颗粒之间存在微米级孔隙,热处理后材料孔隙结构发生变化,大孔隙减少,孔隙分布更加均匀。热处理后材料纳米硬度明显减小,热膨胀系数略增大,微观结构的变化是导致材料性能改变的主要原因。

  5. Fluid Mechanics of Heart Valves and Their Replacements

    Science.gov (United States)

    Sotiropoulos, Fotis; Le, Trung Bao; Gilmanov, Anvar

    2016-01-01

    As the pulsatile cardiac blood flow drives the heart valve leaflets to open and close, the flow in the vicinity of the valve resembles a pulsed jet through a nonaxisymmetric orifice with a dynamically changing area. As a result, three-dimensional vortex rings with intricate topology emerge that interact with the complex cardiac anatomy and give rise to shear layers, regions of recirculation, and flow instabilities that could ultimately lead to transition to turbulence. Such complex flow patterns, which are inherently valve- and patient-specific, lead to mechanical forces at scales that can cause blood cell damage and thrombosis, increasing the likelihood of stroke, and can trigger the pathogenesis of various life-threatening valvular heart diseases. We summarize the current understanding of flow phenomena induced by heart valves, discuss their linkage with disease pathways, and emphasize the research advances required to translate in-depth understanding of valvular hemodynamics into effective patient therapies.

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

    Science.gov (United States)

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

    2016-01-01

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

  7. Heart Valve Structure and Function in Development and Disease

    Science.gov (United States)

    Hinton, Robert B.; Yutzey, Katherine E.

    2014-01-01

    The mature heart valves are made up of highly organized extracellular matrix (ECM) and valve interstitial cells (VIC) surrounded by an endothelial cell layer. The ECM of the valves is stratified into elastin-, proteoglycan- and collagen-rich layers that confer distinct biomechanical properties to the leaflets and supporting structures. Signaling pathways have critical functions in primary valvulogenesis as well as maintenance of valve structure and function over time. Animal models provide powerful tools to study valve development and disease processes. Valve disease is a significant public health problem and increasing evidence implicates aberrant developmental mechanisms underlying pathogenesis. Further studies are necessary to determine regulatory pathway interactions underlying pathogenesis in order to generate new avenues for novel therapeutics. PMID:20809794

  8. Signs of inflammation in different types of heart valve disease : The VOCIN study

    OpenAIRE

    Wallby, Lars

    2008-01-01

    Heart valve dysfunction is a relatively common condition in the population, whereas significant heart valve disease is more unusual. The cause of different types of heart valve disease depends on which valve is concerned. Rheumatic heart valve disease, has for a long time been considered to constitute a post-inflammatory condition. During the 1990s it was also shown that the so-called non-rheumatic or degenerative tricuspid aortic stenosis, comprised signs of inflammation. In this study, 118 ...

  9. Current status of permanent total artificial hearts.

    Science.gov (United States)

    Davis, P K; Rosenberg, G; Snyder, A J; Pierce, W S

    1989-01-01

    Pneumatic total artificial heats, although demonstrating utility as temporary mechanical circulatory support devices, have not demonstrated a great deal of promise as permanent cardiac replacements. The increasing number of patients who would be candidates for total heart replacement suggests a large role for a permanent implantable total artificial heart. To that end, the Pennsylvania State University is developing an electric motor-driven total artificial heart; the results with implants in calves are encouraging. In this device, a roller-screw mechanism is used to translate the rotation of a brushless direct-current motor into rectilinear motion of a pusher-plate assembly, which in turn empties the blood sacs. The total artificial heart of the future will function under automatic control without percutaneous leads, and this should provide the patient with a nearly normal life-style. Although further experimental efforts are necessary to prepare the device for clinical trials, the technology to provide a safe and reliable electric blood-pump system is at hand. PMID:2912392

  10. Expression of the CD44 Protein in the Heart Valves Affected with Rheumatic Heart Disease

    Directory of Open Access Journals (Sweden)

    R. Vijayalakshmi

    2010-01-01

    Full Text Available Problem statement: The primary aim was to study the expression of CD44 protein in the heart valves removed surgically for either stenosis or regurgitation and to study the morphology of valves using histochemical staining. Approach: We studied 107 valves which were collected from the International Centre for Cardio Thoracic and Vascular Diseases. Results: Aortic and mitral valves were obtained from the centre and processed in research pathology lab. CD44 protein is a receptor for the ligand hyaluronic acid which causes inflammation in the heart valves. A total of 107 valves were studied. Of the 61 mitral valves studied 38 (62.2% showed CD44 positivity as brownish granules within the cytoplasm. Of the 46 aortic valves studied 19 (41.3% showed CD44 positivity as brownish granules within the cytoplasm. The valves showed evidence of past inflammation showing thick and thin walled blood vessels and lymphocytes. CD44 protein increased in 62.2% of mitral valves, of which 60.5% were from patients presenting when they were less than 40 years old. CD44 protein increased in 41.3% of aortic valves, of which 63.15% were from patients presenting when they were less than 40 years old. CD44 positivity was seen in 57 valves as brownish granules within the cytoplasm of the cell. CD44 protein increased in 53.27% of mitral and aortic valves, of which 63.15% were from the males patients. CD44 protein increased in 53.27% of mitral and aortic valves, of which 36.84% were from the females patients. Conclusion/Recommendations: The results showed CD44 is over expressed in the heart valves removed surgically for stenosis or regurgitation where the hyaluronic acid content is high.

  11. Tissue engineered heart valves based on human cells

    OpenAIRE

    Schmidt, D.; Hoerstrup, S P

    2006-01-01

    Valvular heart disease is still a significant cause of morbidity and mortality worldwide. Clinically used valve replacements including mechanical valves as well as fixed biological xeno- or homografts are associated with several major disadvantages. Alternatively, tissue engineering aims at the fabrication of autologous living cardiovascular replacements with the potential to grow and to repair, particularly for paediatric applications. Therefore, autologous cells are harvested and seeded ont...

  12. Tissue engineered heart valves based on human cells

    OpenAIRE

    Schmidt, D.; Hoerstrup, S P

    2007-01-01

    Valvular heart disease is still a significant cause of morbidity and mortality worldwide. Clinically used valve replacements including mechanical valves as well as fixed biological xeno- or homografts are associated with several major disadvantages. Alternatively, tissue engineering aims at the fabrication of autologous living cardiovascular replacements with the potential to grow and to repair, particularly for paediatric applications. Therefore, autologous cells are harvested and seeded ont...

  13. [Heart valves after 22 years - good long-term function of aortic homograft, advanced impairment in function of atrioventricular valves].

    Science.gov (United States)

    Michalski, Błazej; Chrzanowski, Lukasz; Krzemińska-Pakula, Maria; Kasprzak, Jarosław D

    2010-03-01

    We report a case of a 61-year-old female patient with a history of aortic valve replacement, who was admitted to our hospital with symptoms and signs of decompensated heart failure (NYHA class III). Transthoracic echocardiogram revealed mitral valve and tricuspid valve regurgitation (III grade) with normal function of aortic valve homograft implanted 22 years ago. The patient underwent cardiosurgical mitral valve replacement and tricuspid valve annuloplasty with very good result. An aortic valve homograft may be the best alternative to a mechanical valves for a young female patients. PMID:20411462

  14. Processing of Prosthetic Heart Valve Sounds from Anechoic Tank Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J V; Meyer, A W

    2001-03-20

    People with serious cardiac problems have had their life span extended with the development of the prosthetic heart valve. However, the valves operate continuously at approximately 39 million cycles per year and are therefore subject to structural failures either by faulty design or material fatigue. The development of a non-invasive technique using an acoustic contact microphone and sophisticated signal processing techniques has been proposed and demonstrated on limited data sets. In this paper we discuss an extension of the techniques to perform the heart valve tests in an anechoic like. Here the objective is to extract a ''pure'' sound or equivalently the acoustical vibration response of the prosthetic valves in a quiet environment. The goal is to demonstrate that there clearly exist differences between values which have a specific mechanical defect known as single leg separation (SLS) and non-defective valves known as intact (INT). We discuss the signal processing and results of anechoic acoustic measurements on 50 prosthetic valves in the tank. Finally, we show the results of the individual runs for each valve, point out any of the meaningful features that could be used to distinguish the SLS from INT and summarize the experiments.

  15. Effects of bileaflet mechanical heart valve orientation on coronary flow

    Science.gov (United States)

    Haya, Laura; Tavoularis, Stavros

    2015-11-01

    The aortic sinus is approximately tri-radially symmetric, but bileaflet mechanical heart valves (BMHVs), which are commonly used to replace diseased aortic valves, are bilaterally symmetric. This mismatch in symmetry suggests that the orientation in which a BMHV is implanted within the aortic sinus affects the flow characteristics downstream of it. This study examines the effect of BMHV orientation on the flow in the coronary arteries, which originate in the aortic sinus and supply the heart tissue with blood. Planar particle image velocimetry measurements were made past a BMHV mounted at the inlet of an anatomical aorta model under physiological flow conditions. The complex interactions between the valve jets, the sinus vortex and the flow in the right coronary artery were elucidated for three valve orientations. The coronary flow rate was directly affected by the size, orientation, and time evolution of the vortex in the sinus, all of which were sensitive to the valve's orientation. The total flow through the artery was highest when the valve was oriented with its axis of symmetry intersecting the artery's opening. The findings of this research may assist surgeons in choosing the best orientation for BMHV implantation. The bileaflet valve was donated by St. Jude Medical. Financial support was provided by the Natural Sciences and Engineering Research Council of Canada.

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

    OpenAIRE

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

    2015-01-01

    Purpose Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy; the latter display better fluid dynamic behavior but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the hemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of 2 groups of newly developed supra-annula...

  17. Nuclear-powered artificial heart system

    International Nuclear Information System (INIS)

    As reported to the 9th IECEC, a bench model version of a nuclear-powered artificial heart system to be used as a replacement for the natural heart was constructed and tested as part of a broader U.S. ERDA program. A report is given of the system design and integration, bench testing, and field support equipment of an implantable and advanced version of the bench model incorporating some of the component developments reported to the 10th IECEC. The basic elements of the system are a 32-watt Pu-238 heat source, a Stirling engine thermal converter, a coupling mechanism, and a mechanical blood pump drive actuating, alternatively, two artificial ventricles of polymeric material. As tested on the bench using a mock circulation, the system provides approximately 9 liters/minute at 120/80 mm Hg aortic pressure. At 190/145 mm Hg aortic pressure, the maximum flow decreases to about 7 liters/minute

  18. Physical activity increases survival after heart valve surgery

    DEFF Research Database (Denmark)

    Lund, K; Sibilitz, K L; Berg, S K;

    2016-01-01

    OBJECTIVES: Increased physical activity predicts survival and reduces risk of readmission in patients with coronary heart disease. However, few data show how physical activity is associated with survival and readmission after heart valve surgery. Objective were to assess the association between...... physical activity levels 6-12 months after heart valve surgery and (1) survival, (2) hospital readmission 18-24 months after surgery and (3) participation in exercise-based cardiac rehabilitation. METHODS: Prospective cohort study with registry data from The CopenHeart survey, The Danish National Patient...... Register and The Danish Civil Registration System of 742 eligible patients. Physical activity was quantified with the International Physical Activity Questionnaire and analysed using Kaplan-Meier analysis and Cox regression and logistic regression methods. RESULTS: Patients with a moderate to high physical...

  19. Understanding Heart Valve Problems and Causes

    Science.gov (United States)

    ... heartbeat with a stethoscope. A murmur may sound like a “whooshing” noise of blood flowing under pressure as it moves from one chamber to the next, or it may sound like an extra click when a valve allows back ...

  20. Use of Circular Foldable Nitinol Blades for Resecting Calcified Aortic Heart Valves

    Science.gov (United States)

    Hauck, Florian; Wendt, Daniel; Stühle, Sebastian; Kawa, Emilia; Wendt, Hermann; Müller, Wiebke; Thielmann, Matthias; Kipfmüller, Brigitte; Vogel, Bernd; Jakob, Heinz

    2009-08-01

    The use of percutaneous aortic valve implantation is limited, as the native calcified valve is left in situ. A new device has been developed for resecting calcified aortic valves, using collapsible nickel-titanium blades: laser-cut T-structures of Nitinol sheet-material (Ni51Ti49 at.%) have been grinded on a high-speed milling cutter to produce cutting edges which have been given the shape of half-circles afterwards. These have been connected to each other and to struts by using rivets which also serve as articulating axes for the cutting ring. The blades are folded around these axes and retreated into a tube to be inserted in the heart through the calcified valve leaflets. Once released, the cutting edges regain their ring-shape. By combining rotation of the ring with a translating movement against a second ring of slightly greater diameter on the instrument, a punching process is created which cuts the calcified valve leaflets and leaves a circular annulus, where a prosthesis can be fixed. In vitro cutting of artificially calcified valves ( n = 6) resulted in a resection time of t = 22 ± 6.29 s with a maximum turning moment of M = 2.4 ± 1.27 Nm, proving the function and the feasibility of the concept.

  1. Heart failure after aortic valve substitution due to severe hypothyroidism

    DEFF Research Database (Denmark)

    Munk, Kim; Sørensen, Stine Heidenheim; Andersen, Niels Holmark;

    2008-01-01

    We report a case of a 70-year-old female with considerable co-morbidities (Type 2 diabetes, Leiden factor V mutation, mild to moderate chronic obstructive pulmonary disease) and a recent biological aortic valve substitution, who was admitted due to circulatory collapse caused by severe heart fail...

  2. Thromboembolism and mechanical heart valves : A randomized study revisited

    NARCIS (Netherlands)

    Kuntze, CEE; Blackstone, EH; Ebels, T

    1998-01-01

    Background. This study was designed to revise and substantiate previous inferences, based on short-term follow-up, about differences in the incidence of anticoagulant-related events after heart valve replacement among patients who had been randomly assigned to receive either a Bjork-Shiley, Edwards-

  3. Motion analysis of mechanical heart valve prosthesis utilizing high-speed video

    Science.gov (United States)

    Adlparvar, Payam; Guo, George; Kingsbury, Chris

    1993-01-01

    The Edwards-Duromedics (ED) mechanical heart valve prosthesis is of a bileaflet design, incorporating unique design features that distinguish its performance with respect to other mechanical valves of similar type. Leaflet motion of mechanical heart valves, particularly during closure, is related to valve durability, valve sounds and the efficiency of the cardiac output. Modifications to the ED valve have resulted in significant improvements with respect to leaflet motion. In this study a high-speed video system was used to monitor the leaflet motion of the valve, and to compare the performance of the Modified Specification to that of the Original Specification using a St. Jude Medical as a control valve.

  4. Rheumatic heart disease with triple valve involvement

    OpenAIRE

    BRAMBATI, MATTEO; LAURENZI, PIER FRANCESCO; MARLETTA, FIORANGELA; MANINA, GIORGIA; COMINA, DENISE PROVVIDENZA; PRESTON, NGAMBE MANDI; CASSETTI, GIUSEPPINA; MERLO, CHIARA; Volpi, Michele; MUSSO, ROBERTA; LA ROCCA, ROBERTO

    2013-01-01

    Acute rheumatic fever (ARF) is a postinfectious, nonsuppurative sequela of pharyngeal infection caused by Streptococcus pyogenes, or Group A β hemolytic Streptococcus (GABHS). Of the associated symptoms, only damage to the heart’s valvular tissue, or rheumatic heart disease (RHD), can become a chronic condition leading to congestive heart failure, stroke, endocarditis, and death. ARF is the most common cause of cardiac disease in children in developing countries. A joint meeting o...

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

    OpenAIRE

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

    2014-01-01

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

  6. What Is a Total Artificial Heart?

    Science.gov (United States)

    ... Trials Links Related Topics Heart Failure Heart Surgery Heart Transplant How the Heart Works Ventilator/Ventilator Support Send ... has become so severe that all treatments, except heart transplant , have failed. (A heart transplant is surgery to ...

  7. Modeling prosthetic heart valves for numerical analysis of blood flow in the heart

    International Nuclear Information System (INIS)

    This paper extends our previous work on numerical analysis of blood flow in the heart. In that work the boundary forces were evaluated by solving a fixed-point problem, which we now reformulate as a problem in optimization. This optimization problem, which involves the energy function from which the boundary forces are derived, is solved by Murray's modification of Newton's method. The energy function turns out to be an extremely useful tool in modeling prosthetic heart valves. To enforce a constraint on the valve, we use an energy function which is zero when the constraint is satisfied and positive other wise. The energy function must be invariant under translation and rotation so that convervation of momentum and angular momentum will be satisfied. We use this technique to construct computer models of several prosthetic valves, and we study the flow patterns of these valves in our computer test chamber

  8. Qualification research study of naturally and artificially aged solenoid valves in accident simulations

    International Nuclear Information System (INIS)

    A qualification research program conducted on naturally and artificially aged solenoid valves revealed no significant differences in performance during seismic tests, but some differences during main-steam-line-break/loss-of-coolantaccident (MSLB/LOCA) simulation. Although the naturally aged valves were subjected to less severe aging than the artificially aged valves, they failed earlier than the artificially aged valves in the MSLB/LOCA test. Only a valve with metal seats performed satisfactorily throughout the program. All other valves tested experienced failure or diminished functional capability as a consequence of degradation of the EPDM components (seals, seats, diaphragms). Degradation manifested itself in the form of severe compression set, embrittlement, and adherence of tacky material to bounding metal parts. There were also two coil failures. This paper analyzes the causes of degradation and reviews the implications of the program with respect to qualification methodology and the adequacy of the valves for safety-related service

  9. Tangible nanocomposites with diverse properties for heart valve application

    Science.gov (United States)

    Vignesh Vellayappan, Muthu; Balaji, Arunpandian; Priyadarshini Subramanian, Aruna; Aruna John, Agnes; Jaganathan, Saravana Kumar; Murugesan, Selvakumar; Mohandas, Hemanth; Supriyanto, Eko; Yusof, Mustafa

    2015-06-01

    Cardiovascular disease claims millions of lives every year throughout the world. Biomaterials are used widely for the treatment of this fatal disease. With the advent of nanotechnology, the use of nanocomposites has become almost inevitable in the field of biomaterials. The versatile properties of nanocomposites, such as improved durability and biocompatibility, make them an ideal choice for various biomedical applications. Among the various nanocomposites, polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane, bacterial cellulose with polyvinyl alcohol, carbon nanotubes, graphene oxide and nano-hydroxyapatite nanocomposites have gained popularity as putative choices for biomaterials in cardiovascular applications owing to their superior properties. In this review, various studies performed utilizing these nanocomposites for improving the mechanical strength, anti-calcification potential and hemocompatibility of heart valves are reviewed and summarized. The primary motive of this work is to shed light on the emerging nanocomposites for heart valve applications. Furthermore, we aim to promote the prospects of these nanocomposites in the campaign against cardiovascular diseases.

  10. Micro and nanotechnologies in heart valve tissue engineering.

    Science.gov (United States)

    Hasan, Anwarul; Saliba, John; Pezeshgi Modarres, Hassan; Bakhaty, Ahmed; Nasajpour, Amir; Mofrad, Mohammad R K; Sanati-Nezhad, Amir

    2016-10-01

    Due to the increased morbidity and mortality resulting from heart valve diseases, there is a growing demand for off-the-shelf implantable tissue engineered heart valves (TEHVs). Despite the significant progress in recent years in improving the design and performance of TEHV constructs, viable and functional human implantable TEHV constructs have remained elusive. The recent advances in micro and nanoscale technologies including the microfabrication, nano-microfiber based scaffolds preparation, 3D cell encapsulated hydrogels preparation, microfluidic, micro-bioreactors, nano-microscale biosensors as well as the computational methods and models for simulation of biological tissues have increased the potential for realizing viable, functional and implantable TEHV constructs. In this review, we aim to present an overview of the importance and recent advances in micro and nano-scale technologies for the development of TEHV constructs. PMID:27414719

  11. Flow mapping of heart valves: Natural and prosthetic

    International Nuclear Information System (INIS)

    Over the past decade there have been many in vitro studies conducted on the velocity and turbulence fields in the vicinity of prosthetic aortic heart valves. A vast majority of these studies have utilized one dimensional laser Doppler anemometer (LDA) systems. Recently, two dimensional LDA systems have been utilized to directly measure turbulent shear stresses under pulsatile flow conditions. LDA is considered the gold standard for in vitro velocity and turbulence measurements. In addition, numerical models have also been developed to simulate flow through prosthetic heart valves. With the advent of more powerful computers these simulation techniques have become more and more sophisticated, and are beginning to provide more realistic and useful information standards. In this session there are presentations made by engineers, scientists and physicians, that encompass in vitro LDA studies, computer simulation techniques, and ultrasound Doppler studies in animals and human subjects

  12. Pulmonary heart valve replacement using stabilized acellular xenogeneic scaffolds; effects of seeding with autologous stem cells

    Directory of Open Access Journals (Sweden)

    Harpa Marius Mihai

    2015-12-01

    Full Text Available Background: We hypothesized that an ideal heart valve replacement would be acellular valve root scaffolds seeded with autologous stem cells. To test this hypothesis, we prepared porcine acellular pulmonary valves, seeded them with autologous adipose derived stem cells (ADSCs and implanted them in sheep and compared them to acellular valves.

  13. Making Artificial Heart Components – Selected Aspects Of Casting Technology

    Directory of Open Access Journals (Sweden)

    Sobczak J.J.

    2015-09-01

    Full Text Available This study shown possibilities of Rapid Prototyping techniques (RP and metal casting simulation software (MCSS, including non inertial reference systems. RP and MCSS have been used in order to design and produce essential elements for artificial heart. Additionally it has been shown possibilities of Fused Deposition Modeling (FDM technique and DodJet technology using prototyped elements of rotodynamic pump. MAGMASOFT® software allowed to verify the cast kit heart valves model. Optical scanner Atos III enabled size verification of experimental elements supplied by rapid prototyping together with metal casting elements. Due to the selection of ceramic materials and assessment of molten metal – ceramic reactivity at high temperatures together with pattern materials selection model it was possible to design, manufacture a ceramic mould for titanium based alloys. The casting structure modification has been carried out by means of high isostatic pressure technique (HIP. The quality assessment of the casting materials has been performed using X-ray fluorescence (XRF, ARL 4460 Optical Emission Spectrometer, metallographic techniques and X-ray computed tomography.

  14. COMPUTER MODELING IN THE DEVELOPMENT OF ARTIFICIAL VENTRICLES OF HEART

    Directory of Open Access Journals (Sweden)

    L. V. Belyaev

    2011-12-01

    Full Text Available In article modern researches of processes of development of artificial ventricles of heart are described. Advanta- ges of application computer (CAD/CAE technologies are shown by development of artificial ventricles of heart. The systems developed with application of the given technologies are submitted. 

  15. Comparison of naturally and artificially aged solenoid valves in accident simulations

    International Nuclear Information System (INIS)

    A qualification research program conducted on naturally and artificially aged solenoid valves revealed no significant differences in performance during seismic tests, but some differences during main-steam-line-break/loss-of-coolant-accident (MSLB/LOCA) simulation. Although the naturally aged valves were subjected to less severe aging than the artificially aged valves, they failed earlier than the artificially aged valves in the MSLB/LOCA test. Only a valve with metal seats performed satisfactorily throughout the program. All other valves tested experiences failure or diminished functional capability as a consequence of degradation of the EPDM components (seals, seats, diaphragms). Degradation manifested itself in the form of severe compressive set, embrittlement, and adherence of tacky material to bounding metal parts. There were also two coil failures. This paper analyzes the causes of degradation and recommends ways of improving the qualification method. 3 figs.

  16. Anticoagulation in pregnant females with mechanical heart valves

    International Nuclear Information System (INIS)

    To evaluate the complications and outcome of anticoagulation therapy in pregnant females with valvular heart diseases. All pregnant females with prosthetic heart valves admitted in Armed Forces Institute of Cardiology from Jan 2004 to Dec 2004 were included in this study Basic demographic data including age, duration of pregnancy and complications observed were recorded. Warfarin was replaced with un-fractionated heparin (UFH) in first trimester and after that warfarin was continued with a targeted INR between 2.0-3.0. At 36 weeks warfarin was stopped and UFH was added; however, if patient went into spontaneous labour before this then immediate caesarian section was performed and UFH was restarted 4-6 hours after delivery along with oral warfarin. Out of 21 patients, sixteen (76.1%) had mitral valve diseases and five (23.9%) had both mitral and atrial. Majority (42.3%)of patients were in age group 26-30 years. Eleven (52.2%) reported in 9th month of gestation. Complications observed were hypertension (1), transient ischaemic attacks (1), pulmonary embolism (1), haemoptysis (1) and abortion (1). All patients, except one had successful completion of pregnancy. No case of foetal abnormality was seen. In 76% patients, daily dose of warfarin was <5 mg. Thrombo-prophylaxis in pregnancy with warfarin and UFH with an INR of 2.0-3.0 is effective in preventing thrombotic complications in females with mechanical valves without resulting in increase hemorrhagic complications. (author)

  17. Comparison between Doppler echocardiography and hot-film anemometry in measuring the turbulent shear stress downstream of artificial mitral valves: a methodological study

    Institute of Scientific and Technical Information of China (English)

    SUN Yi; LI Rui-jie; LI Gan-niu; LI Bin; WANG Yu; MA Run-wei; YANG Bai-hui

    2013-01-01

    Background Turbulent shear stress (TSS) plays an important role in the research of fluid dynamics of heart valves.This study aimed to perform a quantitative study of TSS downstream of porcine artificial mitral valves in order to verify the correlation of hot-film anemometry (HFA) and Doppler echocardiography combined with computer-aided image analysis for the detection of TSS.Methods A porcine model of mitral valve replacement was established.HFA and Doppler ultrasound techniques were used to directly and indirectly measure TSS-relevant parameters of the artificial mitral valve following different mitral valve replacements:different approaches were used to reserve the subvalvular apparatus of the mitral valve.A correlation analysis was then carried out.Results There was a significant correlation between the HFA and Doppler ultrasound combined with computer-aided image analysis of the TSS at the same time and at the same site.No significant difference was found in the TSS measured by the two methods.Conclusions Compared with HFA,Doppler echocardiography combined with computer-aided image analysis is a safe,non-invasive,and real-time method that enables accurate and quantitative detection of TSS downstream in vivo,objectively reflecting the flow field downstream of the artificial mitral valve.Doppler ultrasound combined with computeraided image analysis can be employed for quantitatively evaluating the downstream hemodynamic performance of the mitral valve.

  18. Adaptive Finite Elements for Monolithic Fluid-StructureInteraction on a Prolongated Domain: Applied to an Heart Valve Simulation

    OpenAIRE

    Wick, Thomas

    2011-01-01

    In this work, we apply a fluid-structure interaction method to a long axis heart valve simulation. Our method of choice is based on a monolithic coupling scheme for fluid-structure interaction, where the fluid equations are rewritten in the arbitrary Lagrangian Eulerian' framework. To prevent back-flow of waves in the structure due to its hyperbolic nature, a damped structure equation is solved on an artificial layer that prolongates the computational domain. This coupling is stable on th...

  19. Numerical Simulation Of Flow Through An Artificial Heart

    Science.gov (United States)

    Rogers, Stuart; Kutler, Paul; Kwak, Dochan; Kiris, Centin

    1991-01-01

    Research in both artificial hearts and fluid dynamics benefits from computational studies. Algorithm that implements Navier-Stokes equations of flow extended to simulate flow of viscous, incompressible blood through articifial heart. Ability to compute details of such flow important for two reasons: internal flows with moving boundaries of academic interest in their own right, and many of deficiencies of artificial hearts attributable to dynamics of flow.

  20. Dynamic heart phantom with functional mitral and aortic valves

    Science.gov (United States)

    Vannelli, Claire; Moore, John; McLeod, Jonathan; Ceh, Dennis; Peters, Terry

    2015-03-01

    Cardiac valvular stenosis, prolapse and regurgitation are increasingly common conditions, particularly in an elderly population with limited potential for on-pump cardiac surgery. NeoChord©, MitraClipand numerous stent-based transcatheter aortic valve implantation (TAVI) devices provide an alternative to intrusive cardiac operations; performed while the heart is beating, these procedures require surgeons and cardiologists to learn new image-guidance based techniques. Developing these visual aids and protocols is a challenging task that benefits from sophisticated simulators. Existing models lack features needed to simulate off-pump valvular procedures: functional, dynamic valves, apical and vascular access, and user flexibility for different activation patterns such as variable heart rates and rapid pacing. We present a left ventricle phantom with these characteristics. The phantom can be used to simulate valvular repair and replacement procedures with magnetic tracking, augmented reality, fluoroscopy and ultrasound guidance. This tool serves as a platform to develop image-guidance and image processing techniques required for a range of minimally invasive cardiac interventions. The phantom mimics in vivo mitral and aortic valve motion, permitting realistic ultrasound images of these components to be acquired. It also has a physiological realistic left ventricular ejection fraction of 50%. Given its realistic imaging properties and non-biodegradable composition—silicone for tissue, water for blood—the system promises to reduce the number of animal trials required to develop image guidance applications for valvular repair and replacement. The phantom has been used in validation studies for both TAVI image-guidance techniques1, and image-based mitral valve tracking algorithms2.

  1. Raman spectroscopy for diagnosis of calcification in human heart valves

    OpenAIRE

    Otero, Enrique Uceda; Sathaiah, Sokki; Silveira, LandulfoJr.; POMERANTZEFF Pablo Maria Alberto; Pasqualucci, Carlos Augusto Gonçalves

    2004-01-01

    Near-Infrared Raman Spectroscopy (NIRS) has an excellent potential for a rapid, a less invasive and real time diagnosis of various human diseases. The objective of the present study was to apply NIRS for diagnosis of human heart valves and to develop a feasible algorithm to classify the valvular lesions. For Raman studies, a Ti:sapphire laser pumped by an argon laser provided 830 nm excitation. A spectrograph in conjunction with a liquid N2-cooled CCD detected Raman spectra. A total of 97 fra...

  2. Artifact reduction strategies for prosthetic heart valve CT imaging

    OpenAIRE

    Habets, Jesse; Symersky, Petr; Leiner, Tim; de Mol, Bas A. J. M.; Willem P Th M Mali; Budde, Ricardo P.J.

    2012-01-01

    Multislice CT evaluation of prosthetic heart valves (PHV) is limited by PHV-related artifacts. We assessed the influence of different kV settings, a metal artifact reduction filter (MARF) and an iterative reconstruction algorithm (IR) on PHV-induced artifacts in an in vitro model. A Medtronic-Hall tilting disc and St Jude bileafet PHV were imaged using a 64-slice scanner with 100 kV/165 mAs, 120 kV/100 mAs, 140 kV/67 mAs at an equal CTDIvol. Images were reconstructed with (1) filtered back pr...

  3. Artificial heart system thermal insulation component development

    International Nuclear Information System (INIS)

    A concentric cup vacuum multifoil insulation system has been selected by virtue of its size, weight, and thermal performance to insulate the hot radioisotope portion of the thermal converter of an artificial implantable heart system. A factor of 2 improvement in thermal performance, based on the heat loss per number of foil layers (minimum system weight and volume) has been realized over conventional spiral wrapped multifoil vacuum insulation. This improvement is the result of the concentric cup construction to maintain a uniform interfoil spacing and the elimination of corner heat losses. Based on external insulation system dimensions (surface area in contact with host body), heat losses of 0.019 W/ cm2 at 11400K (16000F) and 0.006 W/cm2 at 9200K (12000F) have been achieved. Factors which influence thermal performance of the nickel foil concentric cup insulation system include the number of cups, configuration and method of application of zirconia (ZrO2) spacer material, system pressure, emittance of the cups, and operating temperature

  4. Patient experiences of recovery after heart valve replacement: suffering weakness, struggling to resume normality

    DEFF Research Database (Denmark)

    Berg, Selina Kikkenborg; Zwisler, Ann-Dorthe; Pedersen, Birthe D.;

    2013-01-01

    Heart valve disease is becoming a public health problem due to increasing life expectancy and new treatment methods. Patients are at risk of developing depression, anxiety or post-traumatic stress disorder after heart valve surgery. To better plan proper care, describing and understanding patients...

  5. [Caecal volvulus after heart surgery with artificial circulation].

    Science.gov (United States)

    Korostelev, A N; Kuznetsov, A M; Chzhao, A V

    2016-01-01

    Presented herein is a description of a rare complication, i.e. caecal volvulus, after heart surgery. This case report illustrates difficulty of diagnosis of abdominal organs complications after artificial circulation and necessity of active surgical policy. PMID:27336350

  6. Heart rate and heart rate variability in dogs with different degrees of myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Rasmussen, Caroline Elisabeth; Falk, Bo Torkel; Zois, Nora Elisabeth;

    2011-01-01

    moderate/severe MR and in HF compared to CKCS with no/minimal and mild MR (all P<0.02). Another 10 HRV variables showed the same groupwise differences (all P<0.02), except that the difference between CKCS with mild MR and CKCS with moderate/severe MR did not reach statistical significance. Minimum HR, mean......HEART RATE AND HEART RATE VARIABILITY IN DOGS WITH DIFFERENT DEGREES OF MYXOMATOUS MITRAL VALVE DISEASE. CE Rasmussen1, T Falk1, NE Zois1, SG Moesgaard1, HD Pedersen2, J Häggström3 and LH Olsen1. 1. Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of...... Copenhagen, Frederiksberg, Denmark. 2. Novo Nordic A/S, Maaloev, Denmark. 3. Department of Clinical Sciences, Swedish University of Agricultural Science, Uppsala, Sweden. Heart rate variability (HRV) is an indirect measurement of the autonomic modulation of heart rate (HR). Reduced HRV measured from short...

  7. Acoustic emission condition monitoring of a nuclear power plant check valve using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joon Hyun; Lee, Min Rae [Pusan National University, Pusan (Korea, Republic of); Kim, Jung Teak [Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of)

    2005-11-15

    In this study, an advanced condition monitoring technique based on acoustic emission (AE) detection and artificial neural networks was applied to a check valve, one of the components being used extensively in a safety system of a nuclear power plant (Npp). AE testing for a check valve under controlled flow loop conditions was performed to detect and evaluate disk movement for valve degradation such as wear and leakage due to foreign object interference in a check valve. It is clearly demonstrated that the evaluation of different types of failure modes such as disk wear and check valve leakage were successful by systematically analyzing the characteristics of various AE parameters. It is also shown that the leak size can be determined with an artificial neural network.

  8. Acoustic emission condition monitoring of a nuclear power plant check valve using artificial neural networks

    International Nuclear Information System (INIS)

    In this study, an advanced condition monitoring technique based on acoustic emission (AE) detection and artificial neural networks was applied to a check valve, one of the components being used extensively in a safety system of a nuclear power plant (Npp). AE testing for a check valve under controlled flow loop conditions was performed to detect and evaluate disk movement for valve degradation such as wear and leakage due to foreign object interference in a check valve. It is clearly demonstrated that the evaluation of different types of failure modes such as disk wear and check valve leakage were successful by systematically analyzing the characteristics of various AE parameters. It is also shown that the leak size can be determined with an artificial neural network

  9. Reynolds shear stress for textile prosthetic heart valves in relation to fabric design.

    Science.gov (United States)

    Bark, David L; Yousefi, Atieh; Forleo, Marcio; Vaesken, Antoine; Heim, Frederic; Dasi, Lakshmi P

    2016-07-01

    The most widely implanted prosthetic heart valves are either mechanical or bioprosthetic. While the former suffers from thrombotic risks, the latter suffers from a lack of durability. Textile valves, alternatively, can be designed with durability and to exhibit hemodynamics similar to the native valve, lowering the risk for thrombosis. Deviations from native valve hemodynamics can result in an increased Reynolds Shear Stress (RSS), which has the potential to instigate hemolysis or shear-induced thrombosis. This study is aimed at characterizing flow in multiple textile valve designs with an aim of developing a low profile valve. Valves were created using a shaping process based on heating a textile membrane and placed within a left heart simulator. Turbulence and bulk hemodynamics were assessed through particle imaging velocimetry, along with flow and pressure measurements. Overall, RSS was reduced for low profile valves relative to high profile valves, but was otherwise similar among low profile valves involving different fabric designs. However, leakage was found in 3 of the 4 low profile valve designs driving the fabric design for low profile valves. Through textile design, low profile valves can be created with favorable hemodynamics. PMID:26919564

  10. Improvement on the auxiliary total artificial heart (ATAH) left chamber design.

    Science.gov (United States)

    Andrade, Aron; Fonseca, Jeison; Legendre, Daniel; Nicolosi, Denys; Biscegli, Jose; Pinotti, Marcos; Ohashi, Yukio; Nosé, Yukihiko

    2003-05-01

    The auxiliary total artificial heart (ATAH) is an electromechanically driven artificial heart with reduced dimensions, which is able to be implanted in the right thoracic or abdominal cavities of an average human patient without removing the natural heart or the heart neurohumoral inherent control mechanism for the arterial pressure. This device uses a brushless direct current motor and a mechanical actuator (roller screw) to move two diaphragms. The ATAH's beating frequency is regulated through the change of the left preload, based on Frank-Starling's law, assisting the native heart in obtaining adequate blood flow. The ATAH left and right stroke volumes are 38 ml and 34 ml, respectively, giving approximately 5 L/min of cardiac output at 160 bpm. Flow visualization studies were performed in critical areas on the ATAH left chamber. A closed circuit loop was used with water and glycerin (37%) at 25 degrees C. Amberlite particles (80 mesh) were illuminated by a 1 mm planar helium-neon laser light. With left mean preload fixed at 10 mm Hg and the afterload at 100 mm Hg, the heart rate varied from 60 to 200 bpm. Two porcine valves were used on the inlet and outlet ports. The flow pattern images were obtained using a color micro-camera and a video recorder. Subsequently, these images were digitized using a PC computer. A persistent stagnant flow was detected in the left chamber inlet port. After improvement on the left chamber design, this stagnant flow disappeared. PMID:12752207

  11. Valve Disease

    Science.gov (United States)

    ... Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden Cardiac Arrest Vulnerable Plaque Valve Disease | Share Related terms: heart valves, valve insufficiency, valve regurgitation, valve stenosis, valvular ...

  12. Serotonin Receptors and Heart Valve Disease – it was meant 2B

    OpenAIRE

    Hutcheson, Joshua D.; Setola, Vincent; Roth, Bryan L.; Merryman, W. David

    2011-01-01

    Carcinoid heart disease was one of the first valvular pathologies studied in molecular detail, and early research identified serotonin produced by oncogenic enterochromaffin cells as the likely culprit in causing changes in heart valve tissue. Researchers and physicians in the mid-1960s noted a connection between the use of several ergot-derived medications with structures similar to serotonin and the development of heart valve pathologies similar to those observed in carcinoid patients. The ...

  13. The Edwards SAPIEN Transcatheter Heart Valve for Calcific Aortic Stenosis: A Review of the Valve, Procedure, and Current Literature

    OpenAIRE

    Holoshitz, Noa; Kavinsky, Clifford J.; Hijazi, Ziyad M.

    2012-01-01

    The Edwards SAPIEN™ transcatheter heart valve (Edwards Lifesciences LLC, Irvine, CA, USA) is approved by the US Food and drug administration for use in the aortic position in patients with severe aortic stenosis who are not surgical candidates. This approval was backed by data from the Placement of AoRTic TraNscathetER Valve (PARTNER) I clinical trial, which showed the valve to be superior to standard medical therapy in high-risk nonoperative patients in cohort B of the trial. Although insert...

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

    Directory of Open Access Journals (Sweden)

    Ben Zhang

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

  15. Reoperation for Prosthetic Heart Valve Dysfunction: 19 Years' Experience

    OpenAIRE

    Masri, Zahi; Girardet, Roland; Attum, Abdulla; Barbie, Ronald; Yared, Isam; Lansing, Allan

    1990-01-01

    Between September 1968 and October 1987, 152 patients (66 males and 86 females; age range, 15 to 79 years) underwent 1 or more reoperations (total, 179) for prosthetic valve dysfunction at our hospital. In this report, we present material and statistics reflecting our experience with the last reoperation in these 152 patients. The procedures involved the mitral valve in 93 patients, the aortic valve in 38 patients, double valves (aortic and mitral) in 19, and the tricuspid valve in 2. Sixty-f...

  16. Control system for an artificial heart

    Science.gov (United States)

    Gebben, V. D.; Webb, J. A., Jr.

    1970-01-01

    Inexpensive industrial pneumatic components are combined to produce control system to drive sac-type heart-assistance blood pump with controlled pulsatile pressure that makes pump rate of flow sensitive to venous /atrial/ pressure, while stroke is centered about set operating point and pump is synchronized with natural heart.

  17. Structural organization of normally located mitral valve chordae tendineae of the human heart

    Directory of Open Access Journals (Sweden)

    Fedonyuk L.Ya.

    2014-09-01

    Full Text Available Background. The mitral valve complex of the human heart consists of: the fibrous annulus, valve leaflets, chordae tendineae and papillary muscles. Deficiency or degeneration one of these structures may result in the dysfunction of the valvular apparatus. Topography and structure of the chordae tendineae effect to the normal functioning of heart valve complex and its hemodynamics, due to the aim of our research was to examine the peculiarities of the structural organization normally located mitral valve chordae tendineae of the human heart. Methods. The investigation was made on sectional material. We used light microscopy and immunohistochemistry methods. Results. The chordae tendineae are cord-like tendons that connect the papillary muscles to the valve leaflets in the heart. The chordeae tendineae were covered by endocardium which contained superficial layer of endothelium. Subendocardial layer includes loosely located collagen and elastic fibers which were interwoven with each other. Cor of the chordae are composed of bundles of densely packed collagen fibrils with few elastic fibers. Conclusion. The investigations allowed to receive a new objective data on some structural peculiarities of chordae tendineae of the human mitral valve that later can become the basis for the differential diagnosis of disease, including valvular heart pathology. Citation: Fedonyuk LYa, Malyk YuYu. [Structural organization of normally located mitral valve chordae tendineae of the human heart]. Morphologia. 2014;8(3:61-6. Ukrainian.

  18. Three-component laser Doppler velocimetry measurements in the vicinity of mechanical heart valves in a mock-circulatory loop

    Science.gov (United States)

    Meyer, Richard Scott

    Streakline flow visualization and three-component laser Doppler velocimetry were conducted in a mock-circulatory loop on four mechanical heart valve types in the mitral position. Measurements were conducted in the regurgitant flow region proximal to the valve. Results for the Bjork-Shiley Monostrutsp{TM} valve showed a highly non-uniform flow at valve closure, with very large velocities in the minor orifice region. These velocities were on the order of 15-20 mps and lasted less than one millisecond. Following closure, an interval of sustained regurgitant flow persisted for the duration of systole. Reynolds stresses were calculated from three-dimensional data, and yielded a maximum of 8,100 dyne/cmsp2. Values as high as 80,000 dyne/cmsp2 were calculated during the initial spike, but due to the intermittency of the spike, they are artificially high. Similar measurements were conducted in the minor orifice of the Medtronic-Hall valve, and maximum velocities of about 4 mps were measured during the sustained regurgitant flow. Maximum Reynolds shear stresses were about 7,000 dyne/cmsp2. The velocity spike at closing was noted with this valve also. Two-component measurements around the center hole in the occluder showed a sustained jet with maximum velocities of about 1 mps, and maximum Reynolds shear stresses of about 2,000 dyne/cmsp2. Measurements in the St. Jude Medical valve showed velocities and stresses to be very low. No closing spike was measured, and sustained velocities were observed in the hinge region of about 0.2 mps with maximum stresses of about 1,000 dyne/cmsp2. The CarboMedicssp{TM} valve showed a regurgitant jets emanating from the gap between the leaflet and valve housing ring, with velocities of 3.3 mps for the duration of systole, and calculated stresses of 8,100 dyne/cmsp2. No closing spike was noted. Differences between two and three-dimensional Reynolds shear stresses were significant only at locations where two-dimensional calculated values were

  19. Laser Doppler anemometry measurements of steady flow through two bi-leaflet prosthetic heart valves

    OpenAIRE

    Ovandir Bazan; Jayme Pinto Ortiz; Francisco Ubaldo Vieira Junior; Reinaldo Wilson Vieira; Nilson Antunes; Fabio Bittencourt Dutra Tabacow; Eduardo Tavares Costa; Orlando Petrucci Junior

    2013-01-01

    INTRODUCTION: In vitro hydrodynamic characterization of prosthetic heart valves provides important information regarding their operation, especially if performed by noninvasive techniques of anemometry. Once velocity profiles for each valve are provided, it is possible to compare them in terms of hydrodynamic performance. In this first experimental study using laser doppler anemometry with mechanical valves, the simulations were performed at a steady flow workbench. OBJECTIVE: To compare unid...

  20. Design and performance of heart assist or artificial heart control systems

    Science.gov (United States)

    Webb, J. A., Jr.; Gebben, V. D.

    1978-01-01

    The factors leading to the design of a controlled driving system for either a heart assist pump or artificial heart are discussed. The system provides square pressure waveform to drive a pneumatic-type blood pump. For assist usage the system uses an R-wave detector circuit that can detect the R-wave of the electrocardiogram in the presence of electrical disturbances. This circuit provides a signal useful for synchronizing an assist pump with the natural heart. It synchronizes a square wave circuit, the output of which is converted into square waveforms of pneumatic pressure suitable for driving both assist device and artificial heart. The pressure levels of the driving waveforms are controlled by means of feedback channels to maintain physiological regulation of the artificial heart's output flow. A more compact system that could achieve similar regulatory characteristics is also discussed.

  1. Experience in procurement and processing of heart valves at the Northwest Tissue Center

    International Nuclear Information System (INIS)

    The Northwest Tissue Center established a human heart valve program in 199 1. It is one of four non-profit tissue banks and one for-profit program that recover and process heart valves in the United States. During the eight years in which the Northwest Tissue Center has been involved in heart valve banking, there have been a total of 673 hearts procured for processing. The age of the donors ranged from <1 to 44 years with a mean of 26.2 years, 66% werw male,and 6.5% of the hearts procered were discarded due to a variety of medical and criteria reason. The primary reasons for differal were questions of possible cancer and questions of high risk behavior/social history. Of the 1,264 cardiovascular tissues processed, 6% were lost because of donor history, 17% were lost because of microbiology results, and 5% were lost because of donor serology . There were total a total of 190 aortic valves and 48 pulmonic conduits transplanted over this time period. The mean age of the recipients was 23.4 with a median or 23 years; 102 of the recipients were less than one year of age. Males comprised 62% of the recipients. Since 1993, there has been a clear shift towards more use of pulmonic valves over aortic valves as a results of the acceptance of the Ross procedure. Early in the program, reports were received from surgeons that some heart valves appeared to have cracks in the conduits. Experimentations in the laboratory led to the discovery that thawing too rapidly would result in cracking of these materials. Packaging was designed to reduce the rate of thawing and this has resolved the problem with cracking. The heart valve program at the Northwest Tissue Center has been very successful in providing the necessary valves for patients in the Northwest Region of the United States

  2. Heart murmurs audible across the room in children with mitral valve prolapse.

    OpenAIRE

    Fiddler, G I; Scott, O

    1980-01-01

    Three children are described in whom an unusual heart murmur was intermittently audible in the same room without a stethoscope. Subsequent investigations disclosed mitral valve prolapse in all three patients.

  3. Hydrodynamic characteristics of mechanical heart valve prostheses in steady and pulsatile flow

    Czech Academy of Sciences Publication Activity Database

    Klimeš, František; Kořenář, Josef

    2002-01-01

    Roč. 9, č. 4 (2002), s. 249-258. ISSN 1210-2717 Institutional research plan: CEZ:AV0Z2060917 Keywords : mechanical heart valve prostheses * flow visualization- steady and pulsatile flow Subject RIV: BO - Biophysics

  4. Artificial heart thermal converter component research and development

    International Nuclear Information System (INIS)

    Under U.S. ERDA contract, a radioisotope powered artificial heart system to be used as a replacement for the diseased natural heart is under development by the Westinghouse Advanced Energy Systems Division and Philips Laboratories. A portion of the program activity is in research and development of components for the Stirling cycle thermal converter. Developments in current areas of thermal converter R and D investigation are discussed, including the control system, lubrication system, magnetic shaft coupling, rotary seals, and materials joining

  5. Total Artificial Heart Implantation after Excision of Right Ventricular Angiosarcoma

    OpenAIRE

    Bruckner, Brian A.; Abu Saleh, Walid K.; Al Jabbari, Odeaa; Copeland, Jack G.; Estep, Jerry D.; Loebe, Matthias; Reardon, Michael J.

    2016-01-01

    Primary cardiac sarcomas, although rare, are aggressive and lethal, requiring thorough surgical resection and adjuvant chemotherapy for the best possible outcome. We report the case of a 32-year-old woman who underwent total artificial heart implantation for right-sided heart failure caused by right ventricular angiosarcoma. For the first several weeks in intensive care, the patient recovered uneventfully. However, a postoperative liver biopsy indicated hepatocellular injury consistent with p...

  6. Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach

    OpenAIRE

    Scarsoglio, Stefania; Camporeale, Carlo; Guala, Andrea; Ridolfi, Luca

    2015-01-01

    Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm (NSR) in absence of any valvular pathology. Among the most common parameters inte...

  7. Fluid–structure interaction analysis of bioprosthetic heart valves: Significance of arterial wall deformation

    OpenAIRE

    Hsu, Ming-Chen; Kamensky, David; Bazilevs, Yuri; Sacks, Michael S; Hughes, Thomas J. R.

    2014-01-01

    We propose a framework that combines variational immersed-boundary and arbitrary Lagrangian–Eulerian (ALE) methods for fluid–structure interaction (FSI) simulation of a bioprosthetic heart valve implanted in an artery that is allowed to deform in the model. We find that the variational immersed-boundary method for FSI remains robust and effective for heart valve analysis when the background fluid mesh undergoes deformations corresponding to the expansion and contraction of the elastic artery....

  8. Modeling of artificial stiction in steam turbine control valve

    International Nuclear Information System (INIS)

    The steam turbine control valves play a pivotal role in regulating the output power of the turbine in a commercial nuclear power plant. In this paper the turbine system refers to Ulchin units 3 and 4. The modeling of friction in steam turbine control valve is presented. Instead of a detailed physical model of the control valve friction, the data-driven models are adopted for modeling the friction to obtain an easier friction identification and faster calculation time. Some computational results by using the MARS thermal hydraulic analysis code are presented to show the effect of friction on the total mass flow at the inlet of the high pressure turbine. The computational results demonstrate that the friction will initiate fluctuations on the total mass flow at the turbine inlet

  9. Gamma Ray Sterilization of Starr-Edwards Heart Valve Prostheses

    International Nuclear Information System (INIS)

    Starr-Edwards valves have normally been sterilized by exposure to ethylene oxide or by autoclaving. Patients having a prosthetic valve replacement are known to have a higher incidence of endocarditis in comparison with patients in which no prosthesis has been used. Ethylene oxide will only sterilize the surface of the valve and autoclaving has caused distortion of the polytetrafluorethylene ring. Work has been done on the effect of gamma radiation on the components of these valve prostheses and is given in detail. The bacteriological efficiency, at a total absorbed dose of 2. 5 Mrad, has been established. Thirty valves treated by this method have now been inserted and twelve patients have been examined post-operatively for a period of one to two years. All valves are working normally and there has been no evidence of blood-borne infection or malfunction of the valve. (author)

  10. Radionuclide power source for artificial heart autonomic apparatus

    International Nuclear Information System (INIS)

    Works on creating autonomous artificial heart devices with radionuclide heat source are described. Calculated and experimental parameters of 238Pu base radionuclide thermoelectric RITEG generators designed for supplying perspective blood pump electric drives are presented. RITEG structure is described and the prospects of increasing its efficiency are shown

  11. Reliability studies for the nuclear-powered artificial heart program

    International Nuclear Information System (INIS)

    By assuming that the failures of an artificial heart system with a mean life of 10 y can be modeled by a particular probability distribution, both the probability of a failure in the system within t years and the reliability required of each subsystem and component were investigated

  12. Reliability studies for the nuclear-powered artificial heart program

    Energy Technology Data Exchange (ETDEWEB)

    Horita, M.; Zeigler, R.K.

    1976-04-01

    By assuming that the failures of an artificial heart system with a mean life of 10 y can be modeled by a particular probability distribution, both the probability of a failure in the system within t years and the reliability required of each subsystem and component were investigated.

  13. Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach

    CERN Document Server

    Scarsoglio, Stefania; Guala, Andrea; Ridolfi, Luca

    2015-01-01

    Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm (NSR) in absence of any valvular pathology. Among the most common parameters interpreting the valvular function, the most useful turns out to be the regurgitant volume. During AF both atrial valves do not seem to worsen their performance, while the ventricular efficiency is remarkably reduced.

  14. Fluid dynamics of heart valves during atrial fibrillation: a lumped parameter-based approach.

    Science.gov (United States)

    Scarsoglio, S; Camporeale, C; Guala, A; Ridolfi, L

    2016-08-01

    Atrial fibrillation (AF) consequences on the heart valve dynamics are usually studied along with a valvular disfunction or disease, since in medical monitoring, the two pathologies are often concomitant. Aim of the present work is to study, through a stochastic lumped-parameter approach, the basic fluid dynamics variations of heart valves, when only paroxysmal AF is present with respect to the normal sinus rhythm in absence of any valvular pathology. Among the most common parameters interpreting the valvular function, the most useful turns out to be the regurgitant volume. During AF, both atrial valves do not seem to worsen their performance, while the ventricular efficiency is remarkably reduced. PMID:26460925

  15. Non-Dimensional Formulation of Ventricular Work-Load Severity Under Concomitant Heart Valve Disease

    Science.gov (United States)

    Dong, Melody; Simon-Walker, Rachael; Dasi, Lakshmi

    2012-11-01

    Current guidelines on assessing the severity of heart valve disease rely on dimensional disease specific measures and are thus unable to capture severity under a concomitant heart valve disease scenario. Experiments were conducted to measure ventricular work-load in an in-house in-vitro left heart simulator. In-house tri-leaflet heart valves were built and parameterized to model concomitant heart valve disease. Measured ventricular power varied non-linearly with cardiac output and mean aortic pressure. Significant data collapse could be achieved by the non-dimensionalization of ventricular power with cardiac output, fluid density, and a length scale. The dimensionless power, Circulation Energy Dissipation Index (CEDI), indicates that concomitant conditions require a significant increase in the amount of work needed to sustain cardiac function. It predicts severity without the need to quantify individual disease severities. This indicates the need for new fluid-dynamics similitude based clinical guidelines to assist patients with multiple heart valve diseases. Funded by the American Heart Association.

  16. Cinematics and sticking of heart valves in pulsatile flow test.

    Science.gov (United States)

    Köhler, J; Wirtz, R

    1991-05-01

    The aim of the project was to develop laboratory test devices for studies of the cinematics and sticking behaviour of technical valve protheses. The second step includes testing technical valves of different types and sizes under static and dynamic conditions. A force-deflection balance was developed in order to load valve rims by static radial forces until sticking or loss of a disc (sticking- and clamping-mould point) with computer-controlled force deflection curves. A second deflection device was developed and used for prosthetic valves in the aortic position of a pulsatile mock circulation loop with simultaneous video-cinematography. The stiffness of technical valve rims varied between 0.20 (St. Jude) and about 1.0 N/micron (metal rim valves). The stiffness decreased significantly with increasing valve size. Sticking under pulsatile flow conditions was in good agreement with the static deflection measurements. Hence, valve sticking with increasing danger of thrombus formation is more likely with a less stiff valve rim. In the case of forces acting perpendicularly to the pendulum axis, the clamping mould-point of the valve can be reached, followed by disc dislodgement. PMID:1864654

  17. Outcome of left heart mechanical valve replacement in West African children - A 15-year retrospective study

    Directory of Open Access Journals (Sweden)

    Tamatey Martin

    2011-04-01

    Full Text Available Abstract Background The West African sub-region has poor health infrastructure. Mechanical valve replacement in children from such regions raises important postoperative concerns; among these, valve-related morbidity and complications of lifelong anticoagulation are foremost. Little is known about the long-term outcome of mechanical valve replacement in West Africa. We sought to determine the outcome of mechanical valve replacement of the left heart in children from this sub-region. Method We conducted a retrospective review of all consecutive left heart valve replacements in children ( Results One hundred and fourteen patients underwent mitral valve replacement (MVR, aortic valve replacement (AVR or mitral and aortic valve replacements (MAVR. Their ages ranged from 6-18 years (13.3 ± 3.1 years. All patients were in NYHA class III or IV. Median follow up was 9.1 years. MVR was performed in 91 (79.8% patients, AVR in 13 (11.4% and MAVR in 10 (8.8% patients. Tricuspid valve repair was performed concomitantly in 45 (39.5% patients. There were 6 (5.3% early deaths and 6 (5.3% late deaths. Preoperative left ventricular dysfunction (ejection fraction Conclusion Mechanical valve replacement in West African children has excellent outcomes in terms of mortality, valve-related events, and reoperation rate. Preoperative left ventricular dysfunction is the primary determinant of mortality within the first 2 years of valve replacement. The risk of valve-related complications is acceptably low. Anticoagulation is well tolerated with a very low risk of bleeding even in this socioeconomic setting.

  18. Mitral valve operations at a high-volume pediatric heart center: Evolving techniques and improved survival with mitral valve repair versus replacement

    Directory of Open Access Journals (Sweden)

    Christopher W Baird

    2012-01-01

    Full Text Available Mitral valve disease is quite variable and can occur as an isolated defect or in association with other complex left sided lesions. These lesions are often best described with detailed pre-operative imaging studies to define the valve anatomy and to access associated left heart disease. Depending on the type of mitral valve disease, various surgical repair techniques have led to improved survival in the recent era. We describe lesion specific approach to mitral valve repair and results.

  19. Inspection of an artificial heart by the neutron radiography technique

    International Nuclear Information System (INIS)

    The neutron radiography technique was employed to inspect an artificial heart prototype which is being developed to provide blood circulation for patients expecting heart transplant surgery. The radiographs have been obtained by the direct method with a gadolinium converter screen along with the double coated Kodak-AA emulsion film. The artificial heart consists of a flexible plastic membrane located inside a welded metallic cavity, which is employed for blood pumping purposes. The main objective of the present inspection was to identify possible damages in this plastic membrane, produced during the welding process of the metallic cavity. The obtained radiographs were digitized as well as analysed in a PC and the improved images clearly identify several damages in the plastic membrane, suggesting changes in the welding process

  20. Inspection of an artificial heart by the neutron radiography technique

    Science.gov (United States)

    Pugliesi, R.; Geraldo, L. P.; Andrade, M. L. G.; Menezes, M. O.,; Pereira, M. A. S.; Maizato, M. J. S.

    1999-11-01

    The neutron radiography technique was employed to inspect an artificial heart prototype which is being developed to provide blood circulation for patients expecting heart transplant surgery. The radiographs have been obtained by the direct method with a gadolinium converter screen along with the double coated Kodak-AA emulsion film. The artificial heart consists of a flexible plastic membrane located inside a welded metallic cavity, which is employed for blood pumping purposes. The main objective of the present inspection was to identify possible damages in this plastic membrane, produced during the welding process of the metallic cavity. The obtained radiographs were digitized as well as analysed in a PC and the improved images clearly identify several damages in the plastic membrane, suggesting changes in the welding process.

  1. Inspection of an artificial heart by the neutron radiography technique

    CERN Document Server

    Pugliesi, R; Andrade, M L G; Menezes, M O; Pereira, M A S; Maizato, M J S

    1999-01-01

    The neutron radiography technique was employed to inspect an artificial heart prototype which is being developed to provide blood circulation for patients expecting heart transplant surgery. The radiographs have been obtained by the direct method with a gadolinium converter screen along with the double coated Kodak-AA emulsion film. The artificial heart consists of a flexible plastic membrane located inside a welded metallic cavity, which is employed for blood pumping purposes. The main objective of the present inspection was to identify possible damages in this plastic membrane, produced during the welding process of the metallic cavity. The obtained radiographs were digitized as well as analysed in a PC and the improved images clearly identify several damages in the plastic membrane, suggesting changes in the welding process.

  2. Engineering of a polymer layered bio-hybrid heart valve scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Jahnavi, S., E-mail: jani84@gmail.com [Stem Cell and Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036, TN (India); Tissue Culture Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojappura, Trivandrum, Kerala 695012 (India); Kumary, T.V., E-mail: tvkumary@yahoo.com [Tissue Culture Laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojappura, Trivandrum, Kerala 695012 (India); Bhuvaneshwar, G.S., E-mail: gs.bhuvnesh@gmail.com [Trivitron Innovation Centre, Department of Engineering Design, Indian Institute of Technology Madras, Chennai 600036, TN (India); Natarajan, T.S., E-mail: tsniit@gmail.com [Conducting Polymer laboratory, Department of Physics, Indian Institute of Technology, Madras, Chennai 600036, TN (India); Verma, R.S., E-mail: vermars@iitm.ac.in [Stem Cell and Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036, TN (India)

    2015-06-01

    Current treatment strategy for end stage valve disease involves either valvular repair or replacement with homograft/mechanical/bioprosthetic valves. In cases of recurrent stenosis/ regurgitation, valve replacement is preferred choice of treatment over valvular repair. Currently available mechanical valves primarily provide durability whereas bioprosthetic valves have superior tissue compatibility but both lack remodelling and regenerative properties making their utility limited in paediatric patients. With advances in tissue engineering, attempts have been made to fabricate valves with regenerative potential using various polymers, decellularized tissues and hybrid scaffolds. To engineer an ideal heart valve, decellularized bovine pericardium extracellular matrix (DBPECM) is an attractive biocompatible scaffold but has weak mechanical properties and rapid degradation. However, DBPECM can be modified with synthetic polymers to enhance its mechanical properties. In this study, we developed a Bio-Hybrid scaffold with non-cross linked DBPECM in its native structure coated with a layer of Polycaprolactone-Chitosan (PCL-CH) nanofibers that displayed superior mechanical properties. Surface and functional studies demonstrated integration of PCL-CH to the DBPECM with enhanced bio and hemocompatibility. This engineered Bio-Hybrid scaffold exhibited most of the physical, biochemical and functional properties of the native valve that makes it an ideal scaffold for fabrication of cardiac valve with regenerative potential. - Highlights: • A Bio-Hybrid scaffold was fabricated with PCL-CH blend and DBPECM. • PCL-CH functionally interacted with decellularized matrix without cross linking. • Modified scaffold exhibited mechanical properties similar to native heart valve. • Supported better fibroblast and endothelial cell adhesion and proliferation. • The developed scaffold can be utilized for tissue engineering of heart valve.

  3. Engineering of a polymer layered bio-hybrid heart valve scaffold

    International Nuclear Information System (INIS)

    Current treatment strategy for end stage valve disease involves either valvular repair or replacement with homograft/mechanical/bioprosthetic valves. In cases of recurrent stenosis/ regurgitation, valve replacement is preferred choice of treatment over valvular repair. Currently available mechanical valves primarily provide durability whereas bioprosthetic valves have superior tissue compatibility but both lack remodelling and regenerative properties making their utility limited in paediatric patients. With advances in tissue engineering, attempts have been made to fabricate valves with regenerative potential using various polymers, decellularized tissues and hybrid scaffolds. To engineer an ideal heart valve, decellularized bovine pericardium extracellular matrix (DBPECM) is an attractive biocompatible scaffold but has weak mechanical properties and rapid degradation. However, DBPECM can be modified with synthetic polymers to enhance its mechanical properties. In this study, we developed a Bio-Hybrid scaffold with non-cross linked DBPECM in its native structure coated with a layer of Polycaprolactone-Chitosan (PCL-CH) nanofibers that displayed superior mechanical properties. Surface and functional studies demonstrated integration of PCL-CH to the DBPECM with enhanced bio and hemocompatibility. This engineered Bio-Hybrid scaffold exhibited most of the physical, biochemical and functional properties of the native valve that makes it an ideal scaffold for fabrication of cardiac valve with regenerative potential. - Highlights: • A Bio-Hybrid scaffold was fabricated with PCL-CH blend and DBPECM. • PCL-CH functionally interacted with decellularized matrix without cross linking. • Modified scaffold exhibited mechanical properties similar to native heart valve. • Supported better fibroblast and endothelial cell adhesion and proliferation. • The developed scaffold can be utilized for tissue engineering of heart valve

  4. Fault Diagnosis in Process Control Valve Using Artificial Neural Network

    OpenAIRE

    K. Prabakaran; T. Uma Mageshwari; Prakash, D.; A. Suguna

    2013-01-01

    As modern process industries become more complex, the importance to detect and identify the faulty operation of pneumatic process control valves is increasing rapidly. The prior detection of faults leads to avoiding the system shutdown, breakdown, raw material damage and etc. The proposed approach for fault diagnosis comprises of two processes such as fault detection and fault isolation. In fault diagnosis, the difference between the system outputs and model outputs called as residuals are us...

  5. Fault Diagnosis in Process Control Valve Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    K. Prabakaran

    2013-05-01

    Full Text Available As modern process industries become more complex, the importance to detect and identify the faulty operation of pneumatic process control valves is increasing rapidly. The prior detection of faults leads to avoiding the system shutdown, breakdown, raw material damage and etc. The proposed approach for fault diagnosis comprises of two processes such as fault detection and fault isolation. In fault diagnosis, the difference between the system outputs and model outputs called as residuals are used to detect and isolate the faults. But in the control valve it is not an easy process due to inherent nonlinearity. The particular values of five measurable quantities from the valve are depend on the commonly occurring faults such as Incorrect supply pressure, Diaphragm leakage and Actuator vent blockage. The correlations between these parameters from the fault values for each operating condition are learned by a multilayer BP Neural Network. The parameter consideration is done through the committee of Development and Application of Methods for Actuator Diagnosis in Industrial Control Systems (DAMADICS. The simulation results using MATLab prove that BP neural network has the ability to detect and identify various magnitudes of the faults and can isolate multiple faults. In addition, it is observed that the network has the ability to estimate fault levels not seen by the network during training.

  6. Cardiac rehabilitation increases physical capacity but not mental health after heart valve surgery

    DEFF Research Database (Denmark)

    Sibilitz, Kirstine L; Berg, Selina K; Rasmussen, Trine B;

    2016-01-01

    OBJECTIVE: The evidence for cardiac rehabilitation after valve surgery remains sparse. Current recommendations are therefore based on patients with ischaemic heart disease. The aim of this randomised clinical trial was to assess the effects of cardiac rehabilitation versus usual care after heart.......40) or the exploratory physical and mental outcomes. Cardiac rehabilitation increased the occurrence of self-reported non-serious adverse events (11/72 vs 3/75, p=0.02). CONCLUSIONS: Cardiac rehabilitation after heart valve surgery significantly improves VO2 peak at 4 months but has no effect on mental health and other...

  7. Availability of, referral to and participation in exercise-based cardiac rehabilitation after heart valve surgery

    DEFF Research Database (Denmark)

    Hansen, Tina B; Berg, Selina K; Sibilitz, Kirstine L;

    2015-01-01

    BACKGROUND: As with ischaemic heart disease, cardiac rehabilitation (CR) is recommended for patients undergoing heart valve surgery; recommendations are based on limited evidence. The organization of CR programmes and factors associated with uptake among patients undergoing heart valve surgery have...... variation. The overall uptake rate was 52%. Simultaneous CABG was associated with a higher probability of referral to CR (OR 2.02 (95%CI 1.12-3.65)); being unmarried (0.44 (0.27-0.72)) and having TAVI with a lower probability (0.26; 0.13-0.52). The referral pattern varied across administrative regions, with...

  8. Simulation of blood flow through an artificial heart

    Science.gov (United States)

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

    1991-01-01

    A numerical simulation of the incompressible viscous flow through a prosthetic tilting disk heart valve is presented in order to demonstrate the current capability to model unsteady flows with moving boundaries. Both steady state and unsteady flow calculations are done by solving the incompressible Navier-Stokes equations in 3-D generalized curvilinear coordinates. In order to handle the moving boundary problems, the chimera grid embedding scheme which decomposes a complex computational domain into several simple subdomains is used. An algebraic turbulence model for internal flows is incorporated to reach the physiological values of Reynolds number. Good agreement is obtained between the numerical results and experimental measurements. It is found that the tilting disk valve causes large regions of separated flow, and regions of high shear.

  9. Multigated radionuclide study of the total artificial heart

    International Nuclear Information System (INIS)

    A permanent total artificial heart, the Jarvik-7, was implanted into a 61-year-old male with a severe cardiomyopathy. Gated radionuclide studies were performed in the patient both prior to surgery and following implantation. Preoperative gated radionuclide cardiac studies revealed marked left ventricular enlargement, severe hypokinesis and a left ventricular ejection fraction of 10%. The right ventricle was moderately enlarged with a 27% ejection fraction. Following implantation of the Jarvik-7 artificial heart, gated cardiac studies were performed with a computer gated by a signal from the heart controller. The left ventricular ejection fraction was 69% and the right ventricular ejection fraction was 62%. This compared to a theoretical ejection fraction of 74% for each ventricle based on chamber anatomy. There was excellent ventricular emptying. Phase analysis showed uniform diaphragm motion. The use of gated cardiac studies in humans may prove helpful in evaluating mechanical problems with the artificial heart, such as manlfunction of the diaphragm, before they become clinically apparent. (orig.)

  10. A heart team's perspective on interventional mitral valve repair

    DEFF Research Database (Denmark)

    Treede, Hendrik; Schirmer, Johannes; Rudolph, Volker;

    2012-01-01

    Surgical mitral valve repair carries an elevated perioperative risk in the presence of severely reduced ventricular function and relevant comorbidities. We sought to assess the feasibility of catheter-based mitral valve repair using a clip-based percutaneous edge-to-edge repair system in selected...

  11. CD133 antibody conjugation to decellularized human heart valves intended for circulating cell capture.

    Science.gov (United States)

    Vossler, John D; Min Ju, Young; Williams, J Koudy; Goldstein, Steven; Hamlin, James; Lee, Sang Jin; Yoo, James J; Atala, Anthony

    2015-09-01

    The long term efficacy of tissue based heart valve grafts may be limited by progressive degeneration characterized by immune mediated inflammation and calcification. To avoid this degeneration, decellularized heart valves with functionalized surfaces capable of rapid in vivo endothelialization have been developed. The aim of this study is to examine the capacity of CD133 antibody-conjugated valve tissue to capture circulating endothelial progenitor cells (EPCs). Decellularized human pulmonary valve tissue was conjugated with CD133 antibody at varying concentrations and exposed to CD133 expressing NTERA-2 cl.D1 (NT2) cells in a microflow chamber. The amount of CD133 antibody conjugated on the valve tissue surface and the number of NT2 cells captured in the presence of shear stress was measured. Both the amount of CD133 antibody conjugated to the valve leaflet surface and the number of adherent NT2 cells increased as the concentration of CD133 antibody present in the surface immobilization procedure increased. The data presented in this study support the hypothesis that the rate of CD133(+) cell adhesion in the presence of shear stress to decellularized heart valve tissue functionalized by CD133 antibody conjugation increases as the quantity of CD133 antibody conjugated to the tissue surface increases. PMID:26333364

  12. RNA-seq analysis to identify novel roles of scleraxis during embryonic mouse heart valve remodeling.

    Directory of Open Access Journals (Sweden)

    Damien N Barnette

    Full Text Available Heart valve disease affects up to 30% of the population and has been shown to have origins during embryonic development. Valvulogenesis begins with formation of endocardial cushions in the atrioventricular canal and outflow tract regions. Subsequently, endocardial cushions remodel, elongate and progressively form mature valve structures composed of a highly organized connective tissue that provides the necessary biomechanical function throughout life. While endocardial cushion formation has been well studied, the processes required for valve remodeling are less well understood. The transcription factor Scleraxis (Scx is detected in mouse valves from E15.5 during initial stages of remodeling, and expression remains high until birth when formation of the highly organized mature structure is complete. Heart valves from Scx-/- mice are abnormally thick and develop fibrotic phenotypes similar to human disease by juvenile stages. These phenotypes begin around E15.5 and are associated with defects in connective tissue organization and valve interstitial cell differentiation. In order to understand the etiology of this phenotype, we analyzed the transcriptome of remodeling valves isolated from E15.5 Scx-/- embryos using RNA-seq. From this, we have identified a profile of protein and non-protein mRNAs that are dependent on Scx function and using bioinformatics we can predict the molecular functions and biological processes affected by these genes. These include processes and functions associated with gene regulation (methyltransferase activity, DNA binding, Notch signaling, vitamin A metabolism (retinoic acid biosynthesis and cellular development (cell morphology, cell assembly and organization. In addition, several mRNAs are affected by alternative splicing events in the absence of Scx, suggesting additional roles in post-transcriptional modification. In summary, our findings have identified transcriptome profiles from abnormal heart valves isolated

  13. Construction of tissue-engineered heart valves by using decellularized scaffolds and endothelial progenitor cells

    Institute of Scientific and Technical Information of China (English)

    FANG Ning-tao; XIE Shang-zhe; WANG Song-mei; GAO Hong-yang; WU Chun-gen; PAN Luan-feng

    2007-01-01

    Background Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. This study was designed to develop a tissue engineering heart valve by using human umbilical cord blood-derived endothelial progenitor cells (EPCs) and decellularized valve scaffolds.Methods Decellularized valve scaffolds were prepared from fresh porcine heart valves. EPCs were isolated from fresh human umbilical cord blood by density gradient centrifugation, cultured for 3 weeks in EGM-2-MV medium, by which time the resultant cell population became endothelial in nature, as assessed by immunofluorescent staining. EPC-derived endothelial cells were seeded onto the decellularized scaffold at 3 × 106 cells/cm2 and cultured under static conditions for 7 days. Proliferation of the seeded cells on the scaffolds was detected using the MTT assay. Tissue-engineered heart valves were analyzed by HE staining, immunofluorescent staining and scanning electron microscopy. The anti-thrombogenic function of the endothelium on the engineered heart valves was evaluated by platelet adhesion experiments and reverse transcription-polymerase chain reaction (RT-PCR) analysis for the expression of endothelial nitric oxide synthase (eNOS) and tissue-type plasminogen activator (t-PA).Results EPC-derived endothelial cells showed a histolytic cobblestone morphology, expressed specific markers of the endothelial cell lineage including von Willebrand factor (vWF) and CD31, bound a human endothelial cell-specific lectin,Ulex Europaeus agglutinin-1 (UEA-1), and took up Dil-labeled low density lipoprotein (Dil-Ac-LDL). After seeding on the decellularized scaffold, the cells showed excellent metabolic activity and proliferation. The cells formed confluent endothelial monolayers atop the decellularized matrix, as assessed by HE staining and immunostaining for vWF and CD31. Scanning electron microscopy demonstrated the occurrence of tight junctions between cells forming the

  14. Stirling/hydraulic artificial heart power source

    International Nuclear Information System (INIS)

    The REL power source combines the high efficiency of Stirling engines with the reliability, efficiency, and flexibility of hydraulic power transfer and control to ensure long system life and physiological effectiveness. Extended life testing has been achieved with an engine (2.6 years) and hydraulic actuator/controller (1.6 years). Peak power source efficiency is 15.5 percent on 5 to 10 watts delivered to the blood pump push plate with 33 watts steady thermal input. Planned incorporation of power source output control is expected to reduce daily average thermal input to 18 watts. Animal in-vivo tests with an assist heart have consistently demonstrated required performance by biological synchronization and effective ventricle relief. Volume and weight are 0.93 liter and 2.4 kg (excluding blood pump) with an additional 0.4 liter of low temperature foam insulation required to preclude tissue thermal damage. Carefully planned development of System 7 is expected to produce major reductions in size

  15. Total Artificial Heart Implantation after Excision of Right Ventricular Angiosarcoma.

    Science.gov (United States)

    Bruckner, Brian A; Abu Saleh, Walid K; Al Jabbari, Odeaa; Copeland, Jack G; Estep, Jerry D; Loebe, Matthias; Reardon, Michael J

    2016-06-01

    Primary cardiac sarcomas, although rare, are aggressive and lethal, requiring thorough surgical resection and adjuvant chemotherapy for the best possible outcome. We report the case of a 32-year-old woman who underwent total artificial heart implantation for right-sided heart failure caused by right ventricular angiosarcoma. For the first several weeks in intensive care, the patient recovered uneventfully. However, a postoperative liver biopsy indicated hepatocellular injury consistent with preoperative chemotherapy. She developed continuing liver failure, from which she died despite good cardiac function. PMID:27303244

  16. Effect of heart rate on the hemodynamics of bileaflet mechanical heart valves' prostheses (St. Jude Medical) in the aortic position and in the opening phase: A computational study.

    Science.gov (United States)

    Jahandardoost, Mehdi; Fradet, Guy; Mohammadi, Hadi

    2016-03-01

    To date, to the best of the authors' knowledge, in almost all of the studies performed around the hemodynamics of bileaflet mechanical heart valves, a heart rate of 70-72 beats/min has been considered. In fact, the heart rate of ~72 beats/min does not represent the entire normal physiological conditions under which the aortic or prosthetic valves function. The heart rates of 120 or 50 beats/min may lead to hemodynamic complications, such as plaque formation and/or thromboembolism in patients. In this study, the hemodynamic performance of the bileaflet mechanical heart valves in a wide range of normal and physiological heart rates, that is, 60-150 beats/min, was studied in the opening phase. The model considered in this study was a St. Jude Medical bileaflet mechanical heart valve with the inner diameter of 27 mm in the aortic position. The hemodynamics of the native valve and the St. Jude Medical valve were studied in a variety of heart rates in the opening phase and the results were carefully compared. The results indicate that peak values of the velocity profile downstream of the valve increase as heart rate increases, as well as the location of the maximum velocity changes with heart rate in the St. Jude Medical valve model. Also, the maximum values of shear stress and wall shear stresses downstream of the valve are proportional to heart rate in both models. Interestingly, the maximum shear stress and wall shear stress values in both models are in the same range when heart rate is St. Jude Medical valve model when heart rate is >90 beats/min (up to ~40% growth compared to that of the native valve). The findings of this study may be of importance in the hemodynamic performance of bileaflet mechanical heart valves. They may also play an important role in design improvement of conventional prosthetic heart valves and the design of the next generation of prosthetic valves, such as percutaneous valves. PMID:26786673

  17. Integrating Valve-Inspired Design Features Into Poly(ethylene glycol) Hydrogel Scaffolds For Heart Valve Tissue Engineering

    OpenAIRE

    Zhang, Xing; Xu, Bin; Puperi, Daniel S.; Yonezawa, Aline L.; Wu, Yan; Tseng, Hubert; Cuchiara, Maude L.; West, Jennifer L.; Grande-Allen, K. Jane

    2014-01-01

    The development of advanced scaffolds that recapitulate the anisotropic mechanical behavior and biological functions of the extracellular matrix in leaflets would be transformative for heart valve tissue engineering. In this study, anisotropic mechanical properties were established in poly(ethylene glycol) (PEG) hydrogels by crosslinking stripes of 3.4 kDa PEG diacrylate (PEGDA) within 20 kDa PEGDA base hydrogels using a photolithographic patterning method. Varying the stripe width and spacin...

  18. Successful heart transplant after 1374 days living with a total artificial heart.

    Science.gov (United States)

    Gerosa, Gino; Gallo, Michele; Bottio, Tomaso; Tarzia, Vincenzo

    2016-04-01

    The CardioWest Total Artificial Heart (CW-TAH) has been approved as a temporary device for bridge to cardiac transplantation and is under investigation for destination therapy by US Food and Drug Administration (FDA). We herein report the longest worldwide survival out of hospital (1374 days) of a patient supported with Cardio West Total Artificial Heart (CW-TAH). This experience is intended as a proof of concept of using CW-TAH as the destination therapy in patients with biventricular failure. PMID:26819291

  19. Computation of incompressible viscous flows through artificial heart devices with moving boundaries

    Science.gov (United States)

    Kiris, Cetin; Rogers, Stuart; Kwak, Dochan; Chang, I.-DEE

    1991-01-01

    The extension of computational fluid dynamics techniques to artificial heart flow simulations is illustrated. Unsteady incompressible Navier-Stokes equations written in 3-D generalized curvilinear coordinates are solved iteratively at each physical time step until the incompressibility condition is satisfied. The solution method is based on the pseudo compressibility approach and uses an implicit upwind differencing scheme together with the Gauss-Seidel line relaxation method. The efficiency and robustness of the time accurate formulation of the algorithm are tested by computing the flow through model geometries. A channel flow with a moving indentation is computed and validated with experimental measurements and other numerical solutions. In order to handle the geometric complexity and the moving boundary problems, a zonal method and an overlapping grid embedding scheme are used, respectively. Steady state solutions for the flow through a tilting disk heart valve was compared against experimental measurements. Good agreement was obtained. The flow computation during the valve opening and closing is carried out to illustrate the moving boundary capability.

  20. The value of MRI in the diagnosis of heart valve diseases

    International Nuclear Information System (INIS)

    Objective: To assess the diagnostic value of the magnetic resonance imaging (MRI) for heart valve disease qualitatively and quantitatively. Methods: From 18th Sep, 2004 to 30th Jun, 2005, 56 consecutive patients underwent MR scanning with multiple sequences, including two-dimensional dark and bright sequences, K-space segmented TrueFISP and FLASH cine sequences, as well as velocity-encoded cine MR(VEC-MR). Morphologic and functional parameters were applied to assess the disease qualitatively and quantitatively. For quantitative analysis, Doppler echocardiography was compared to evaluate the reliability of VEC-MR in assessing the severity of aortic valve disease. Correlations coefficient was analyzed by a statistic software (SPSS 13.0), Psq=0.951, P=0.01 for AS and R=0.965, Rsq=0.932, P<0.01 for AI). Conclusion: Heart valve diseases can be qualitatively and quantitatively evaluated by MR multiple sequences, especially in aortic valve disease. (authors)

  1. Anatomy studies for an artificial heart. Final summary report

    International Nuclear Information System (INIS)

    In the interval from February of 1972 through December of 1977, studies were conducted relating to the anatomical feasibility of implanting a total artificial heart system. These studies included both the calf as an experimental animal as well as the ultimate human recipient of the artificial heart system. Studies with the calf included definition of the thoracic anatomy relative to the size, shape, and vascular connections for implanting the blood pump. To test the animal's tolerance to an implanted engine system, mockups of the thermal converter were implanted chronically in various locations within the calf. No problems developed in retroperitoneal or intraperitoneal implants ranging from 8 to 15 months. A study to determine accelerations experienced by an abdominally implanted thermal converter was performed in calves. Under the most severe conditions, accelerations of a maximum of 34 Gs were experienced. The largest effort was devoted to defining the human anatomy relative to implanting an artificial heart in the thorax. From a number of data sources, including cadavers as well as living patients, a quantitative, statistical analysis of the size and shape of the male thorax was obtained. Finally, an in vivo study of a functional intrathoracic compliance bag in a calf demonstrated the feasibility of this method

  2. Anisotropic Poly(Ethylene Glycol)/Polycaprolactone Hydrogel–Fiber Composites for Heart Valve Tissue Engineering

    OpenAIRE

    Tseng, Hubert; Puperi, Daniel S.; Kim, Eric J.; Ayoub, Salma; Shah, Jay V.; Cuchiara, Maude L.; West, Jennifer L.; Grande-Allen, K. Jane

    2014-01-01

    The recapitulation of the material properties and structure of the native aortic valve leaflet, specifically its anisotropy and laminate structure, is a major design goal for scaffolds for heart valve tissue engineering. Poly(ethylene glycol) (PEG) hydrogels are attractive scaffolds for this purpose as they are biocompatible, can be modified for their mechanical and biofunctional properties, and can be laminated. This study investigated augmenting PEG hydrogels with polycaprolactone (PCL) as ...

  3. Guidance for Removal of Fetal Bovine Serum from Cryopreserved Heart Valve Processing

    OpenAIRE

    Brockbank, Kelvin G.M.; Heacox, Albert E.; Schenke-Layland, Katja

    2010-01-01

    Bovine serum is commonly used in cryopreservation of allogeneic heart valves; however, bovine serum carries a risk of product adulteration by contamination with bovine-derived infectious agents. In this study, we compared fresh and cryopreserved porcine valves that were processed by 1 of 4 cryopreservation formulations, 3 of which were serum-free and 1 that utilized bovine serum with 1.4 M dimethylsulfoxide. In the first serum-free group, bovine serum was simply removed from the cryopreservat...

  4. Fabrication of a Novel Hybrid Scaffold for Tissue Engineered Heart Valve

    Institute of Scientific and Technical Information of China (English)

    Hao HONG; Niangno DONG; Jiawei SHI; Si CHEN; Chao GUO; Ping HU; Hongxu QI

    2009-01-01

    The aim of this study was to fabricate biomatrix/polymer hybrid scaffolds using an elec-trospinning technique. Then tissue engineered heart valves were engineered by seeding mesenchymal stromal cells (MSCs) onto the scaffolds. The effects of the hybrid scaffolds on the proliferation of seed cells, formation of extracellular matrix and mechanical properties of tissue engineered heart valves were investigated. MSCs were obtained from rats. Porcine aortic heart valves were decellularized, coated with poly(3-hydroxybutyrate-co-4-hydroxybutyrate) using an electrospinning technique, and reseeded and cultured over a time period of 14 days. In control group, the decellularized valve scaffolds were re-seeded and cultured over an equivalent time period. Specimens of each group were examined histologi-cally (hematoxylin-eosin [HE] staining, immunohistostaining, and scanning electron microscopy), bio-chemically (DNA and 4-hydroxyproline) and mechanically. The results showed that recellularization was comparable to the specimens of hybrid scaffolds and controls. The specimens of hybrid scaffolds and controls revealed comparable amounts of cell mass and 4-hydroxyproline (P>0.05). However, the specimens of hybrid scaffolds showed a significant increase in mechanical strength, compared to the controls (P<0.05). This study demonstrated the superiority of the hybrid scaffolds to increase the me-chanical strength of tissue engineered heart valves. And compared to the decellularized valve scaffolds,the hybrid scaffolds showed similar effects on the proliferation of MSCs and formation of extracellular matrix. It was believed that the hybrid scaffolds could be used for the construction of tissue engineered heart valves.

  5. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    NARCIS (Netherlands)

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

    2011-01-01

    OBJECTIVES: Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. METHODS

  6. Multidetector CT imaging of mechanical prosthetic heart valves : quantification of artifacts with a pulsatile in-vitro model

    NARCIS (Netherlands)

    Symersky, Petr; Budde, Ricardo P. J.; Westers, Paul; de Mol, Bas A. J. M.; Prokop, Mathias

    2011-01-01

    Objectives Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. Methods

  7. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    NARCIS (Netherlands)

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

    2011-01-01

    Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. A Medtronic Hall ti

  8. Artificial Heart Rejects High Tech? Lessens Learnt from Non-pulsatile VAD with Straight Impeller Vanes

    OpenAIRE

    Qian, Kun-xi

    2007-01-01

    Despite the progresses in developing pulsatile impeller pump and impeller total heart, as well as in applying streamlined impeller vanes, the best results in application of artificial heart pumps have been achieved by nonpulsatile univentricular assist pump with straight impeller vanes until now. It seems all efforts and successes have been done in vain because artificial heart rejects Hi-Tech! This paper recalls some important achievements in R&D of artificial heart in past 25 years and shar...

  9. Heart valve surgery in patients with homozygous sickle cell disease: A management strategy

    Directory of Open Access Journals (Sweden)

    El Mehdi Moutaouekkil

    2015-01-01

    Full Text Available Background: Patients with the homozygous sickle cell disease have increased perioperative mortality. Some indications like heart valve surgery, may justify an exchange blood transfusion to reduce the proportion of hemoglobin S (HbS and complications. Subjects and Methods: We report two female cases aged 20 and 27, of African origin with homozygous sickle cell anemia who underwent heart valve surgery to treat mitral valve regurgitation. This presentation describes the perioperative considerations including anesthesia and postoperative care. Results: A partial exchange blood transfusion decreased HbS levels from respectively, 90% and 84%, 9% to 27% and 34%, and simultaneously treated the anemia. Neither sickling crisis nor acidosis occurred in any patient, and no special postoperative complication occurred. Average hospital stay was 10 days. Currently, the two patients remain alive and free of cardiac symptoms. Discussion: Although the presence of sickle cell disorders is associated with increased risk of sickling and thus vaso-occlusive complications, they should not be taken as a contraindication for heart valve surgery. Nevertheless, monitoring of certain parameters such as venous, arterial oxygen content, pH, and body temperature is mandatory for a better outcome. Furthermore, preoperative exchange transfusion has a positive influence on the outcome of surgery and on the survival of patients undergoing heart valves surgery. Avoiding intraoperative hypoxia, hypothermia, and vaso-constrictive agents, minimizing HbS levels with preoperative exchange transfusion, and ensuring a stress-free environment with the judicious use of sedatives made surgery relatively safe in these cases.

  10. FDA's requirements for in-vivo performance data for prosthetic heart valves.

    Science.gov (United States)

    Johnson, D M; Sapirstein, W

    1994-07-01

    The Food and Drug Administration (FDA) has recently revised its "Replacement Heart Valve Guidance". That document lists the data FDA deems necessary to support the approval of new prosthetic heart valves of all designs, and which should be contained in Premarket Approval Applications for these devices. The guidance covers detailed data requirements for in vitro, animal, and clinical data. This paper is intended to briefly summarize FDA's requirements for in vivo and clinical data. The clinical study must establish that the device is both safe and effective, as compared to currently marketed replacement heart valves. It is possible to achieve this goal using hypothesis testing to compare the results of an observational study against a set of Objective Performance Criteria (OPC) which have been established by the FDA. The establishment of the OPCs was facilitated by a standardized set of definitions of complications published by the American Association of Thoracic Surgery and Society of Thoracic Surgeons (AATS/STS) in 1987/1988. Papers published in peer reviewed journals have utilized this set of definitions for data analysis, providing an ample pool of data from which to establish OPCs. The number of patients required to establish the safety and efficacy of a replacement heart valve, using this approach, is 800 valve years, 400 in the aortic and 400 in the mitral position. Advantages of this approach are reduction in the number of patients and duration of the study. PMID:7952304

  11. Physical principles of artificial stimulation of the heart : Stimulation of the canine heart in situ

    NARCIS (Netherlands)

    Schneider, H.

    1964-01-01

    1. 1. In artificial heart stimulation, the essential quantity is the density of current, , in the intramyocardial wall. Dosage of the pulse amplitude in volts can have serious consequences for the patient. Curve indications in volts on pacemakers and in publications and records must, therefore, be r

  12. Imaging in the context of replacement heart valve development: use of the Visible Heart(®) methodologies.

    Science.gov (United States)

    Bateman, Michael G; Iaizzo, Paul A

    2012-09-01

    In recent years huge strides have been made in the fields of interventional cardiology and cardiac surgery which now allow physicians and surgeons to repair or replace cardiac valves with greater success in a larger demographic of patients. Pivotal to these advances has been significant improvements in cardiac imaging and improved fundamental understanding of valvular anatomies and morphologies. We describe here a novel series of techniques utilized within the Visible Heart(®) laboratory by engineers, scientists, and/or anatomists to visualize and analyze the form and function of the four cardiac valves and to assess potential repair or replacement therapies. The study of reanimated large mammalian hearts (including human hearts) using various imaging modalities, as well as specially prepared anatomical specimens, has enhanced the design, development, and testing of novel cardiac therapies. PMID:24282719

  13. Sox9 is required for precursor cell expansion and extracellular matrix organization during mouse heart valve development

    OpenAIRE

    Lincoln, Joy; Kist, Ralf; Scherer, Gerd; Yutzey, Katherine E.

    2007-01-01

    Heart valve structures derived from mesenchymal cells of the endocardial cushions (EC) are composed of highly organized cell lineages and extracellular matrix. Sox9 is a transcription factor required for both early and late stages of cartilage formation that is also expressed in the developing valves of the heart. The requirements for Sox9 function during valvulogenesis and adult valve homeostasis in mice were examined by conditional inactivation of Sox9 using Tie2-cre and Col2a1-cre transgen...

  14. Decellularized homologous tissue-engineered heart valves as off-the-shelf alternatives to xeno- and homografts

    OpenAIRE

    Dijkman, Petra E; Driessen-Mol, Anita; Frese, Laura; Hoerstrup, Simon P.; Baaijens, Frank P.T.

    2012-01-01

    Decellularized xenogenic or allogenic heart valves have been used as starter matrix for tissue-engineering of valve replacements with (pre-)clinical promising results. However, xenografts are associated with the risk of immunogenic reactions or disease transmission and availability of homografts is limited. Alternatively, biodegradable synthetic materials have been used to successfully create tissue-engineered heart valves (TEHV). However, such TEHV are associated with substantial technologic...

  15. Fiber heart valve prosthesis: Early in vitro fatigue results.

    Science.gov (United States)

    Vaesken, Antoine; Khoffi, Foued; Heim, Frederic; Dieval, Florence; Chakfe, Nabil

    2016-07-01

    Transcatheter aortic valve replacement has become today a largely considered alternative technique to surgical valve replacement in patients with high risk for open chest surgery. Biological valve tissue used in the transcatheter devices has shown success over 5 years now, but the procedure remains expensive. Moreover, different studies point out potential degradations that the tissue can undergo when folded to lower diameter and released in calcified environment with irregular geometry, which may jeopardize the durability of the device. The use of synthetic materials, like textile in particular, to replace biological valve leaflets would help reducing the procedure costs, and limit the degradations when the valve is crimped. Textile polyester material has been extensively used in the vascular surgery and is characterized by outstanding folding and strength properties combined with proven biocompatibility. However, the friction effects that occur between filaments and between yarns within a fabric under flexure loading could be critical for the resistance of the material on the long term. The purpose of this study was to assess the early fatigue performances of textile valve prototypes under accelerated cyclic loading up to 200 Mio cycles. Durability tests show that the fibrous material undergoes rearrangements between fibrous elements within the textile construction and the mechanical properties are modified on the long term. But testing is not complete with 200 Mio cycles. The material should be tested up to a higher number of cycles in future work to test the effective long-term durability. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 986-992, 2016. PMID:25980361

  16. Integrating valve-inspired design features into poly(ethylene glycol) hydrogel scaffolds for heart valve tissue engineering.

    Science.gov (United States)

    Zhang, Xing; Xu, Bin; Puperi, Daniel S; Yonezawa, Aline L; Wu, Yan; Tseng, Hubert; Cuchiara, Maude L; West, Jennifer L; Grande-Allen, K Jane

    2015-03-01

    The development of advanced scaffolds that recapitulate the anisotropic mechanical behavior and biological functions of the extracellular matrix in leaflets would be transformative for heart valve tissue engineering. In this study, anisotropic mechanical properties were established in poly(ethylene glycol) (PEG) hydrogels by crosslinking stripes of 3.4 kDa PEG diacrylate (PEGDA) within 20 kDa PEGDA base hydrogels using a photolithographic patterning method. Varying the stripe width and spacing resulted in a tensile elastic modulus parallel to the stripes that was 4.1-6.8 times greater than that in the perpendicular direction, comparable to the degree of anisotropy between the circumferential and radial orientations in native valve leaflets. Biomimetic PEG-peptide hydrogels were prepared by tethering the cell-adhesive peptide RGDS and incorporating the collagenase-degradable peptide PQ (GGGPQG↓IWGQGK) into the polymer network. The specific amounts of RGDS and PEG-PQ within the resulting hydrogels influenced the elongation, de novo extracellular matrix deposition and hydrogel degradation behavior of encapsulated valvular interstitial cells (VICs). In addition, the morphology and activation of VICs grown atop PEG hydrogels could be modulated by controlling the concentration or micro-patterning profile of PEG-RGDS. These results are promising for the fabrication of PEG-based hydrogels using anatomically and biologically inspired scaffold design features for heart valve tissue engineering. PMID:25433168

  17. Results of Heart Valve Replacement with the SORIN Prosthesis

    OpenAIRE

    Colombo, Tiziano; Donatelli, Francesco; Quaini, Eugenio; Vitali, Ettore; Pellegrini, Alessandro

    1987-01-01

    From March 1977 to December 1981, 872 patients at our institution underwent valve replacement with a pyrolytic carbon tilting disc prosthesis manufactured in Italy by SORIN-Biomedica. To verify the performance characteristics of this prosthesis, we analyzed the intermediate-term results obtained over a cumulative total of 3,041 patient-years (pt-yr) of follow-up.

  18. Plutonium-238 as a heat source for the artificial heart

    International Nuclear Information System (INIS)

    A total artificial heart system powered for 10 years or more by a 238Pu heat source appears feasible in the near future. However, hypothetical risks and injury and apparent misunderstanding surround the application 238Pu. The consequences of 238Pu already released to the environment, the modes of human uptake of 238Pu and biological responses, the criticality aspects of 238Pu and the magnitude and effects of operational radiation exposures upon the recipient of a 238Pu heat source and the recipient's personal contacts is studied

  19. Newly Designed Eccentric Roller Type Total Artificial Heart

    OpenAIRE

    Wada, Hideichi; Fukunaga, Shintaro; Watari, Masanobu; Orihashi, Kazumasa; Sueda, Taijiro; Matsuura, Yuichiro

    2000-01-01

    We have produced an eccentric roller type total artificial heart (ERTAH). As the first step in the development of this ERTAH, we conducted simulations such as a numerical simulation, a mock test, and an acute animal experiment using DeBakey roller pumps to analyze the left-right balance during its operation. The next step was redesigning the blood chambers to improve energy efficiency and implanting the ERTAH with an interatrial shunt into an animal for evaluation of the in vivo performance o...

  20. Artificial heart for humanoid robot using coiled SMA actuators

    Science.gov (United States)

    Potnuru, Akshay; Tadesse, Yonas

    2015-03-01

    Previously, we have presented the design and characterization of artificial heart using cylindrical shape memory alloy (SMA) actuators for humanoids [1]. The robotic heart was primarily designed to pump a blood-like fluid to parts of the robot such as the face to simulate blushing or anger by the use of elastomeric substrates for the transport of fluids. It can also be used for other applications. In this paper, we present an improved design by using high strain coiled SMAs and a novel pumping mechanism that uses sequential actuation to create peristalsis-like motions, and hence pump the fluid. Various placements of actuators will be investigated with respect to the silicone elastomeric body. This new approach provides a better performance in terms of the fluid volume pumped.

  1. Automatic Emboli Detection System for the Artificial Heart

    Science.gov (United States)

    Steifer, T.; Lewandowski, M.; Karwat, P.; Gawlikowski, M.

    In spite of the progress in material engineering and ventricular assist devices construction, thromboembolism remains the most crucial problem in mechanical heart supporting systems. Therefore, the ability to monitor the patient's blood for clot formation should be considered an important factor in development of heart supporting systems. The well-known methods for automatic embolus detection are based on the monitoring of the ultrasound Doppler signal. A working system utilizing ultrasound Doppler is being developed for the purpose of flow estimation and emboli detection in the clinical artificial heart ReligaHeart EXT. Thesystem will be based on the existing dual channel multi-gate Doppler device with RF digital processing. A specially developed clamp-on cannula probe, equipped with 2 - 4 MHz piezoceramic transducers, enables easy system setup. We present the issuesrelated to the development of automatic emboli detection via Doppler measurements. We consider several algorithms for the flow estimation and emboli detection. We discuss their efficiency and confront them with the requirements of our experimental setup. Theoretical considerations are then met with preliminary experimental findings from a) flow studies with blood mimicking fluid and b) in-vitro flow studies with animal blood. Finally, we discuss some more methodological issues - we consider several possible approaches to the problem of verification of the accuracy of the detection system.

  2. Particle Image Velocimetry Study of Pulsatile Flow in Bi-leaflet Mechanical Heart Valves with Image Compensation Method

    OpenAIRE

    Shi, Yubing; Yeo, Tony Joon Hock; Zhao, Yong; Hwang, Ned H. C.

    2006-01-01

    Particle Image Velocimetry (PIV) is an important technique in studying blood flow in heart valves. Previous PIV studies of flow around prosthetic heart valves had different research concentrations, and thus never provided the physical flow field pictures in a complete heart cycle, which compromised their pertinence for a better understanding of the valvular mechanism. In this study, a digital PIV (DPIV) investigation was carried out with improved accuracy, to analyse the pulsatile flow field ...

  3. Transcatheter heart valve with variable geometric configuration: in vitro evaluation.

    Science.gov (United States)

    Young, Ernest; Chen, Ji-Feng; Dong, Owen; Gao, Shengqiang; Massiello, Alex; Fukamachi, Kiyotaka

    2011-12-01

    Clinically, the current transcatheter aortic valve (TAV) technology has shown a propensity for paravalvular leakage; studies have correlated this flaw to increased calcification at the implantation site and with nonideal geometry of the stented valve. The present study evaluated the hydrodynamics of different geometric configurations, in particular the intravalvular considerations. Three TAV devices were made to create a representative, size 26 mm TAV. Hydrodynamics were assessed using a pulse duplicator. The geometries tested were composed of the nominal, elliptical, triangular, and undersized shapes; along with half-constriction, a conformation in which only a portion of the stent was constrained. The TAVs were assessed for transvalvular pressure gradient (TVG), effective orifice area (EOA), and regurgitant fraction. The nominal-sized shape posed a larger TVG (6.2 ± 0.3 mm Hg) than other configurations (P TVG, EOA, and regurgitant fraction. In particular, many of these nonideal configurations demonstrated an increased intravalvular regurgitation. PMID:21951229

  4. Nursing leadership of the transcatheter aortic valve implantation Heart Team: Supporting innovation, excellence, and sustainability.

    Science.gov (United States)

    Lauck, Sandra B; McGladrey, Janis; Lawlor, Cindy; Webb, John G

    2016-05-01

    Transcatheter Aortic Valve Implantation (TAVI) is an innovative and resource-intensive treatment of valvular heart disease. Growing evidence and excellent outcomes are contributing to increased patient demand. The Heart Team is foundational to TAVI programs to manage the complexities of case selection and other aspects of care. The competencies and expertise of nurses are well suited to provide administrative and clinical leadership within the TAVI Heart Team to promote efficient, effective, and sustainable program development. The contributions of nursing administrative and clinical leaders exemplify the leadership roles that nurses can assume in healthcare innovation. PMID:27060802

  5. Cardiac Hemodynamics in the Pathogenesis of Congenital Heart Disease and Aortic Valve Calcification

    Science.gov (United States)

    Nigam, Vishal

    2011-11-01

    An improved understanding of the roles of hemodynamic forces play in cardiac development and the pathogenesis of cardiac disease will have significant scientific and clinical impact. I will focus on the role of fluid dynamics in congenital heart disease and aortic valve calcification. Congenital heart defects are the most common form of birth defect. Aortic valve calcification/stenosis is the third leading cause of adult heart disease and the most common form of acquired valvular disease in developed countries. Given the high incidence of these diseases and their associated morbidity and mortality, the potential translational impact of an improved understanding of cardiac hemodynamic forces is very large. Division of Pediatric Cardiology, Rady Children's Hospital, San Diego

  6. An intelligent remote monitoring system for artificial heart.

    Science.gov (United States)

    Choi, Jaesoon; Park, Jun W; Chung, Jinhan; Min, Byoung G

    2005-12-01

    A web-based database system for intelligent remote monitoring of an artificial heart has been developed. It is important for patients with an artificial heart implant to be discharged from the hospital after an appropriate stabilization period for better recovery and quality of life. Reliable continuous remote monitoring systems for these patients with life support devices are gaining practical meaning. The authors have developed a remote monitoring system for this purpose that consists of a portable/desktop monitoring terminal, a database for continuous recording of patient and device status, a web-based data access system with which clinicians can access real-time patient and device status data and past history data, and an intelligent diagnosis algorithm module that noninvasively estimates blood pump output and makes automatic classification of the device status. The system has been tested with data generation emulators installed on remote sites for simulation study, and in two cases of animal experiments conducted at remote facilities. The system showed acceptable functionality and reliability. The intelligence algorithm also showed acceptable practicality in an application to animal experiment data. PMID:16379373

  7. Heart valve health, disease, replacement, and repair: a 25-year cardiovascular pathology perspective.

    Science.gov (United States)

    Schoen, Frederick J; Gotlieb, Avrum I

    2016-01-01

    The past several decades have witnessed major advances in the understanding of the structure, function, and biology of native valves and the pathobiology and clinical management of valvular heart disease. These improvements have enabled earlier and more precise diagnosis, assessment of the proper timing of surgical and interventional procedures, improved prosthetic and biologic valve replacements and repairs, recognition of postoperative complications and their management, and the introduction of minimally invasive approaches that have enabled definitive and durable treatment for patients who were previously considered inoperable. This review summarizes the current state of our understanding of the mechanisms of heart valve health and disease arrived at through innovative research on the cell and molecular biology of valves, clinical and pathological features of the most frequent intrinsic structural diseases that affect the valves, and the status and pathological considerations in the technological advances in valvular surgery and interventions. The contributions of many cardiovascular pathologists and other scientists, engineers, and clinicians are emphasized, and potentially fruitful areas for research are highlighted. PMID:27242130

  8. Severe Bioprosthetic Mitral Valve Stenosis and Heart Failure in a Young Woman with Systemic Lupus Erythematosus

    Science.gov (United States)

    Wartak, Siddharth; Sadiq, Adnan; Crooke, Gregory; Moskovits, Manfred; Frankel, Robert; Hollander, Gerald; Shani, Jacob

    2016-01-01

    A 23-year-old African American woman with a past medical history of systemic lupus erythematous (SLE), secondary hypertension, and end stage renal disease (ESRD) on hemodialysis for eight years was stable until she developed symptomatic severe mitral regurgitation with preserved ejection fraction. She underwent a bioprosthetic mitral valve replacement (MVR) at outside hospital. However, within a year of her surgery, she presented to our hospital with NYHA class IV symptoms. She was treated for heart failure but in view of her persistent symptoms and low EF was considered for heart and kidney transplant. This was a challenge in view of her history of lupus. We presumed that her stenosis of bioprosthetic valve was secondary to lupus and renal disease. We hypothesized that her low ejection fraction was secondary to mitral stenosis and potentially reversible. We performed a dobutamine stress echocardiogram, which revealed an improved ejection fraction to more than 50% and confirmed preserved inotropic contractile reserve of her myocardium. Based on this finding, she underwent a metallic mitral valve and tricuspid valve replacement. Following surgery, her symptoms completely resolved. This case highlights the pathophysiology of lupus causing stenosis of prosthetic valves and low ejection cardiomyopathy.

  9. RELATION OF PERIOPERATIVE SERUM THYROID HORMONE CHANGES TO HEART DYSFUNCTION IN PATIENTS UNDERGONE CARDIAC VALVE REPLACEMENT

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective To explore the relationship between perioperative serum thyroid hormone changes and heart dysfunction in patients undergone cardiac valve replacement. Methods The serum concentrations of free tri- iodothyronine (),free thyroxine (),total total reverse and thyroid-stimulating hor- mone (TSH) in 20 patients undergone routine rheumatic mitral valve replacement were determined by radioim- munoassay at preoperation, the end of myocardial ischemia, and 2,6,12,24 and 48h postoperation, respectively. The alteration hormones above mentioned were comparatively analysed of the normal heart function group (group I,n = 14) and heart dysfunction group (group I ,n=6) after surgery. Results In comparing group I with group I , the more severe the chronic congestive heart failure, the lower the thyroid hormone level before operation;and subse- quently both progressively lowered T3 level and acute heart dysfunction emerged after operation. The decreased extent of serum thyroid hormone was closely parallel to the severity of heart dysfunction. Gonclusion Perioperatively, de- creased serum FT3 and TT3 concentrations are at least an important humoral factor aggravating heart dysfunction, and the patients with preoperative low T3 should be considered as high-risk valvular surgical cases.

  10. Cell-mediated retraction versus hemodynamic loading - A delicate balance in tissue-engineered heart valves.

    Science.gov (United States)

    van Loosdregt, Inge A E W; Argento, Giulia; Driessen-Mol, Anita; Oomens, Cees W J; Baaijens, Frank P T

    2014-06-27

    Preclinical studies of tissue-engineered heart valves (TEHVs) showed retraction of the heart valve leaflets as major failure of function mechanism. This retraction is caused by both passive and active cell stress and passive matrix stress. Cell-mediated retraction induces leaflet shortening that may be counteracted by the hemodynamic loading of the leaflets during diastole. To get insight into this stress balance, the amount and duration of stress generation in engineered heart valve tissue and the stress imposed by physiological hemodynamic loading are quantified via an experimental and a computational approach, respectively. Stress generation by cells was measured using an earlier described in vitro model system, mimicking the culture process of TEHVs. The stress imposed by the blood pressure during diastole on a valve leaflet was determined using finite element modeling. Results show that for both pulmonary and systemic pressure, the stress imposed on the TEHV leaflets is comparable to the stress generated in the leaflets. As the stresses are of similar magnitude, it is likely that the imposed stress cannot counteract the generated stress, in particular when taking into account that hemodynamic loading is only imposed during diastole. This study provides a rational explanation for the retraction found in preclinical studies of TEHVs and represents an important step towards understanding the retraction process seen in TEHVs by a combined experimental and computational approach. PMID:24268314

  11. Manipulation of the closing transients of bileaflet mechanical heart valves using passive, surface-mounted elements

    Science.gov (United States)

    Simon, Helene

    2005-11-01

    The time-periodic closing of bileaflet mechanical heart valves is accompanied by a strong flow transient that is associated with the formation of a counter-rotating vortex pair near the b-datum line of leaflet edges. The strong transitory shear that is generated by these vortices may be damaging to blood elements and may result in platelet activation. In the present work, these flow transients are mitigated using miniature vortex generator arrays that are embedded on the surface of the leaflets. The closing transients in the absence and presence of the passive vortex generators are characterized using PIV measurements that are phase locked to the leaflet motion. The study utilizes a 25 mm St. Jude Medical valve placed in the aortic position of the Georgia Tech left heart simulator. The valve is subjected to physiological flow conditions: a heart rate of 70 bpm; a cardiac output of 5 l/min; and a mean aortic pressure of 90 mmHg. Measurements of the velocity field in the center plane of the leaflets demonstrate that the dynamics of the transient vortices that precede the formation of the leakage jets can be significantly altered and controlled by relatively simple passive modifications of existing valve designs.

  12. Multiple-Step Injection Molding for Fibrin-Based Tissue-Engineered Heart Valves.

    Science.gov (United States)

    Weber, Miriam; Gonzalez de Torre, Israel; Moreira, Ricardo; Frese, Julia; Oedekoven, Caroline; Alonso, Matilde; Rodriguez Cabello, Carlos J; Jockenhoevel, Stefan; Mela, Petra

    2015-08-01

    Heart valves are elaborate and highly heterogeneous structures of the circulatory system. Despite the well accepted relationship between the structural and mechanical anisotropy and the optimal function of the valves, most approaches to create tissue-engineered heart valves (TEHVs) do not try to mimic this complexity and rely on one homogenous combination of cells and materials for the whole construct. The aim of this study was to establish an easy and versatile method to introduce spatial diversity into a heart valve fibrin scaffold. We developed a multiple-step injection molding process that enables the fabrication of TEHVs with heterogeneous composition (cell/scaffold material) of wall and leaflets without the need of gluing or suturing components together, with the leaflets firmly connected to the wall. The integrity of the valves and their functionality was proved by either opening/closing cycles in a bioreactor (proof of principle without cells) or with continuous stimulation over 2 weeks. We demonstrated the potential of the method by the two-step molding of the wall and the leaflets containing different cell lines. Immunohistology after stimulation confirmed tissue formation and demonstrated the localization of the different cell types. Furthermore, we showed the proof of principle fabrication of valves using different materials for wall (fibrin) and leaflets (hybrid gel of fibrin/elastin-like recombinamer) and with layered leaflets. The method is easy to implement, does not require special facilities, and can be reproduced in any tissue-engineering lab. While it has been demonstrated here with fibrin, it can easily be extended to other hydrogels. PMID:25654448

  13. 儿童人工心脏瓣膜置换术%Heart Valve Replacement in Children

    Institute of Scientific and Technical Information of China (English)

    张镜芳; 陈伟达; 罗征祥; 蔡增欣; 何竞功; 吴若彬; 肖学钧

    1993-01-01

    This article chronicles the experience in treating 37 patients (male 22,female 15.aged 4.5 to 14 yrs)with congenital heart disease (17),rheumatic heart disease(15),congenital and rheumatic (1) and subacute bacterial endocarditis (4).The cardiac function before valve prosthesis replacement was grade Ⅳ in 15,Ⅲ in 13,Ⅱ in 7and Ⅰ in Ⅰ.Of them,25 underwent mitral valve replacement (MVR) and 10 tricupid valve replacement (TVR).Sixteen cases were inserted on biovalve,21 cases on mechanical valve prosthesis.The cardiac function of 13 survivors has been improved with a followed-up of 185 months.The hospital mortality was 24.3%.The indications of MVR are:(1) severe mitral insufficiency with cardiac function of grade Ⅲ or Ⅳ.(2)cardiothoracic ratio of more than 0.6 and (3) an irretrievable mitral valve.If the symptoms of myocadiai ischemia of aortic valvular lesion are obvious,AVR should be considered.The authors suggest that cardiac valve replacement be used prudently,only for patients failing to show improvement after conventional treatment.The mechanical valve prosthesis is the first choice for the left heart lesions and the biovalve is suitable for the right heart.In our series,no one presents symptoms of the growth inconformity with the valve prosthesis.%1975~1991年间,对14岁以下患有心脏瓣膜病变的儿童置换人工心脏瓣膜37例.16例使用生物瓣,21例使用机械瓣.住院死亡9例,术后失随访4例,晚期死亡11例,长期存活13例,已随访6~185个月,其中心功能Ⅰ级11例,Ⅱ级2例,无1例因生长发育出现人工瓣膜相对狭窄.儿童人工心脏瓣膜置换术的适应证宜慎重,只有当内科及外科治疗(如瓣膜整形术)无效时才考虑.儿童左心置换瓣膜应首选机械瓣,生物瓣适用于右心.

  14. Heart Team therapeutic decision-making and treatment in severe aortic valve stenosis

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav Hørsted; Holmberg, Fredrik; Gerds, Thomas Alexander;

    2016-01-01

    Objectives After transcatheter aortic valve implantation (TAVI) has been available for high-risk patients with severe aortic valve stenosis (AVS), the decision-making of the Heart Team (HT) has not been examined. Design All adult patients with severe AVS referred to a large tertiary medical centre...... in 2011 were prospectively included. Multivariate regression analysis identified independent factors associated with treatment decisions. Results A total of 487 patients were included (mean age: 75 years, NYHA class III-IV: 47%). The HT proposed medical therapy (MT) in 35 (7%), TAVI in 60 (12%), and...

  15. LLNL heart valve condition classification project anechoic testing results at the TRANSDEC evaluation facility

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J V

    1999-10-31

    This report first briefly outlines the procedures and support/activation fixture developed at LLNL to perform the heart valve tests in an anechoic-like tank at the US Navy Transducer Evaluation Facility (TransDec) located in San Diego, CA. Next they discuss the basic experiments performed and the corresponding experimental plan employed to gather meaningful data systematically. The signal processing required to extract the desired information is briefly developed along with some of the data. Finally, they show the results of the individual runs for each valve, point out any of the meaningful features and summaries.

  16. Stirling engine with hydraulic power output for powering artificial hearts

    International Nuclear Information System (INIS)

    The DWDL heart power source combines the high efficiency of Stirling engines with the reliability, efficiency, and flexibility of hydraulic power transfer and control to ensure long system life and physiological effectiveness. Extended life testing has already been achieved with an engine module; animal in-vivo tests with an assist heart have consistently demonstrated required performance by biological synchronization and effective ventricle relief. The present System 5 can reliably meet near-term thousand-hour animal in-vivo test goals as far as the durability and efficacy of the power source are concerned. Carefully planned development of System 6 has produced major reductions in size and required input power. Research engine tests have provided the basis for achieving performance goals and the approach for further improvement is well established. The near term goal is 33 W heat input with 16 W input projected for normal physical activity. The goal of reduction of engine module volume to 0.9 liter has been achieved. Demonstrated reliability of 292 d for the engine and 35 d for the full system, as well as effectiveness of the artificial heart power source in short-term in-vivo tests indicate that life-limiting problems are now blood pump reliability and the machine-animal interface

  17. Present and future perspectives on total artificial hearts.

    Science.gov (United States)

    Gerosa, Gino; Scuri, Silvia; Iop, Laura; Torregrossa, Gianluca

    2014-11-01

    Due to shortages in donor organ availability, advanced heart-failure patients are at high risk of further decompensation and often death while awaiting transplantation. This shortage has led to the development of effective mechanical circulatory support (MCS). Currently, various implantable ventricular-assist devices (VADs) are able to provide temporary or long-term circulatory support for many end-stage heart-failure patients. Implantation of a total artificial heart (TAH) currently represents the surgical treatment option for patients requiring biventricular MCS as a bridge to transplant (BTT) or destination therapy (DT). However, the clinical applicability of available versions of positive displacement pumps is limited by their size and associated complications. Application of advanced technology is aimed at solving some of these issues, attempting to develop a new generation of smaller and more effective TAHs to suit a wider patient population. Particular targets for improvement include modifications to the biocompatibility of device designs and materials in order to decrease hemorrhagic and thromboembolic complications. Meanwhile, new systems to power implanted driving units which are fully operational without interruption of skin barriers represent a potential means of decreasing the risk of infections. In this review, we will discuss the history of the TAH, its development and clinical application, the implications of the existing technological solutions, published outcomes and the future outlook for TAHs. PMID:25512901

  18. Wearable air supply for pneumatic artificial hearts and ventricular assist devices.

    Science.gov (United States)

    Sipin, A J; Fabrey, W J; Smith, S H; Doussourd, J D; Olsen, D B

    1992-08-01

    An experimental wearable air supply for pneumatic artificial hearts and ventricular assist devices has been built and tested. The unit eliminates the need for tethering to a large, stationery driver. The miniaturized air supply is designed for ambulatory patients with implanted pulsatile pneumatic total artificial hearts (TAH) or pneumatic left-ventricular assist devices (LVAD), to permit mobility in clinical and home settings. The device has major short-term utility as a supply for pneumatic TAH or VAD bridges in patients awaiting heart transplants. The system design for the wearable driver includes a novel, fast rotary compressor, driven by a brushless direct current (DC) motor to supply air to the ventricle through an electromagnetically actuated directional valve, all controlled by a microcomputer. Stroke volume from 0 to 200 cc; pulse rate from 60 to 160 bpm, and duty cycle from 33% to 50% are selected on a keyboard, and the selected or measured parameters can be shown on a liquid crystal display. For control of delivery from a single ventricular assist device, stroke volume is controlled by variation of compressor speed. In the wearable air supply for a TAH, a single compressor drives both ventricles alternately through a double-acting directional valve. Air volume delivered to the left ventricle is adjusted by variation of compressor speed, and air volume to the right ventricle by variation of ejection time. The effect on blood flow rate of the lower impedance to the right ventricle is compensated by provision of a two-stage compressor, in which a single stage drives the right ventricle, and both stages connected in parallel drive the left ventricle. The overall dimensions of the prototype air supply for driving either a TAH or LVAD are 4.5 by 7.8 by 4.5 inches, including an emergency battery with a duration of 15 to 30 min depending on load. The weight is presently 5.5 lb, but this will be reduced in a production design and for a dedicated LVAD air supply

  19. Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway.

    Directory of Open Access Journals (Sweden)

    Samantha Torres Grams

    Full Text Available Maximal Inspiratory Pressure (MIP is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway.This study aimed to compare the MIP values assessed by standard method (MIPsta and by unidirectional expiratory valve method (MIPuni in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated.This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B at two moments (Tests 1 and 2 to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1] was used to determine intraobserver and interobserver reproducibility.The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O than the mean values for MIPsta (-102.5 ± 23.9 cmH2O (p<0.001. Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91, and high correlation for Test 2 (ICC[2,1] = 0.88. The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86 and evaluator B (ICC[2,1] = 0.77.MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway.

  20. Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway

    Science.gov (United States)

    Grams, Samantha Torres; Kimoto, Karen Yumi Mota; Azevedo, Elen Moda de Oliveira; Lança, Marina; de Albuquerque, André Luis Pereira; de Brito, Christina May Moran; Yamaguti, Wellington Pereira

    2015-01-01

    Introduction Maximal Inspiratory Pressure (MIP) is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway. Objectives This study aimed to compare the MIP values assessed by standard method (MIPsta) and by unidirectional expiratory valve method (MIPuni) in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated. Methods This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B) at two moments (Tests 1 and 2) to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1]) was used to determine intraobserver and interobserver reproducibility. Results The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O) than the mean values for MIPsta (-102.5 ± 23.9 cmH2O) (p<0.001). Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91), and high correlation for Test 2 (ICC[2,1] = 0.88). The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86) and evaluator B (ICC[2,1] = 0.77). Conclusions MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway. PMID:26360255

  1. Pathogenesis of various forms of infection in artificial hearts.

    Science.gov (United States)

    Dobsák, Petr; Vasků, Jaromir; Janci;k, Jiri;; Eicher, Jean Christophe; Wotke, Jiri;

    2003-05-01

    Implanted biomaterials are often inevitably attacked by the bacterial infection. So far this problem has not been sufficiently explained and solved. It represents an 'evergreen' in the artificial heart research. Infection of biomaterials is a completely new clinical entity that profoundly differs from the common clinical course of various kinds of infections and their treatment. These infections are persistent; they resist host defense mechanisms and antibiotic therapy because the nature of these microorganisms has changed due to their protection by the biofilm of some bacteria on the surfaces of implanted biomaterials. In our 66 long-term experiments with total artificial heart (TAH) in 25 animals, the infection and sepsis were the main causes of death. The different organs, attacked by the bacterial and septic complications, varied from case to case as the predominant organs, the function of which ceased to be compatible with further survival. The main foci where the infection started were also very variable. The artificial hearts used in these 25 calves were predominantly of TNS-BRNO-VII type (19 animals), TNS-BRNO-II type (4 animals) and of ROSTOCK TAH type (2 animals). The decrease of the immune defense in the TAH recipients of different intensity was evident during the course of infectious process and simultaneously, the virulence and resistance of the microorganisms against antibiotics substantially increased. The activity of the infectious agents was often combined with increased blood coagulation and thrombi formation. In 5 calves hemolytic and hemorrhagic episodes were observed, and in 15 calves without simultaneous anti-calcification treatment, a primary calcification of driving diaphragms was observed. A common dystrophic calcification sometimes complicated septic thrombogenesis. The tactics of the antibiotic therapy differed according to the results of hemocultivation tests and body temperature and was often supported by the stimulation of the immune

  2. Open heart surgery

    Science.gov (United States)

    ... Heart bypass surgery (coronary artery bypass graft - CABG) Heart transplant Heart valve surgery Hypoplastic left heart repair Minimally ... Heart bypass surgery Heart bypass surgery - minimally invasive Heart transplant Heart valve surgery Hypoplastic left heart syndrome Patent ...

  3. Scedosporium apiosermum infection of the “Native” valve: Fungal endocarditis in an orthotopic heart transplant recipient

    OpenAIRE

    Clement, Meredith E.; Eileen K. Maziarz; Schroder, Jacob N.; Patel, Chetan B.; Perfect, John R.

    2015-01-01

    Scedosporium apiospermum is an increasingly appreciated pathogen in immunosuppressed patients. We present a case of S. apiospermum endocarditis in a 70-year-old male who had undergone orthotopic heart transplant. Echocardiogram demonstrated a 1.4 cm tricuspid valve vegetation. He underwent valve replacement, complicated by fatal massive post-operative haemorrhage. Valve cultures grew S. apiospermum. To our knowledge, our case is the first reported instance of endocarditis caused by S. apiospe...

  4. A reduced-order modeling for efficient design study of artificial valve in enlarged ventricular outflow tracts.

    Science.gov (United States)

    Caiazzo, A; Guibert, R; Vignon-Clementel, I E

    2016-09-01

    A computational approach is proposed for efficient design study of a reducer stent to be percutaneously implanted in enlarged right ventricular outflow tracts (RVOT). The need for such a device is driven by the absence of bovine or artificial valves which could be implanted in these RVOT to replace the absent or incompetent native valve, as is often the case over time after Tetralogy of Fallot repair. Hemodynamics are simulated in the stented RVOT via a reduce order model based on proper orthogonal decomposition, while the artificial valve is modeled as a thin resistive surface. The reduced order model is obtained from the numerical solution on a reference device configuration, then varying the geometrical parameters (diameter) for design purposes. To validate the approach, forces exerted on the valve and on the reducer are monitored, varying with geometrical parameters, and compared with the results of full CFD simulations. Such an approach could also be useful for uncertainty quantification. PMID:26738807

  5. Utilization of artificial neural networks and autoregressive modeling in diagnosing mitral valve stenosis.

    Science.gov (United States)

    Kara, Sadik; Güven, Ayşegül; Okandan, Mustafa; Dirgenali, Fatma

    2006-05-01

    This research is concentrated on the diagnosis of mitral heart valve stenosis through the analysis of Doppler Signals' AR power spectral density graphic with the help of ANN. Multilayer feedforward ANN trained with a Levenberg Marquart backpropagation algorithm was implemented in the MATLAB environment. Correct classification of 94% was achieved, whereas 4 false classifications have been observed for the test group of 68 subjects in total. The designed classification structure has about 97.3% sensitivity, 90.3% specifity and positive prediction is calculated to be 92.3%. The stated results show that the proposed method can make an effective interpretation. PMID:15890326

  6. High reliability linear drive device for artificial hearts

    Science.gov (United States)

    Ji, Jinghua; Zhao, Wenxiang; Liu, Guohai; Shen, Yue; Wang, Fangqun

    2012-04-01

    In this paper, a new high reliability linear drive device, termed as stator-permanent-magnet tubular oscillating actuator (SPM-TOA), is proposed for artificial hearts (AHs). The key is to incorporate the concept of two independent phases into this linear AH device, hence achieving high reliability operation. The fault-tolerant teeth are employed to provide the desired decoupling phases in magnetic circuit. Also, as the magnets and the coils are located in the stator, the proposed SPM-TOA takes the definite advantages of robust mover and direct-drive capability. By using the time-stepping finite element method, the electromagnetic characteristics of the proposed SPM-TOA are analyzed, including magnetic field distributions, flux linkages, back- electromotive forces (back-EMFs) self- and mutual inductances, as well as cogging and thrust forces. The results confirm that the proposed SPM-TOA meets the dimension, weight, and force requirements of the AH drive device.

  7. St. Jude Medical and CarboMedics Mechanical Heart Valves in the Aortic Position: Comparison of Long-Term Results

    OpenAIRE

    Kandemir, Ozer; Tokmakoglu, Hilmi; Yildiz, Ulku; TEZCANER, Tevfik; Yorgancioglu, A. Cem; Gunay, Ilhan; Suzer, Kaya; Zorlutuna, Yaman

    2006-01-01

    We designed this study to compare long-term results of St. Jude Medical and CarboMedics mechanical heart valves in the aortic position. We retrospectively analyzed the results of 174 consecutive patients who received either a St. Jude (n=80) or a CarboMedics (n=94) mechanical aortic valve from March 1992 through October 2004.

  8. Mitral Valve Regurgitation in the LVAD-Assisted Heart Studied in a Mock Circulatory Loop.

    Science.gov (United States)

    May-Newman, K; Fisher, B; Hara, M; Dembitsky, W; Adamson, R

    2016-06-01

    Permanent closure of the aortic valve (AVC) is sometimes performed In LVAD patients, usually when a mechanical valve prosthesis or significant aortic insufficiency is present. Mitral valve regurgitation (MVR) present at the time of LVAD implantation can remain unresolved, representing a limitation for exercise tolerance and a potential predictor of mortality. To investigate the effect of MVR on hemodynamics of the LVAD-supported heart following AVC, studies were performed using a mock circulatory loop. Pressure and flow measured for a range of cardiac function, LVAD speed, and MVR show that cardiac contraction augments aortic pressure by 10-27% over nonpulsatile conditions when the mitral valve functions normally, but decreases with MVR until it reaches the nonpulsatile level. Aortic flow displays a similar trend, demonstrating a 25% decrease from fully functioning to open at 7 krpm, a 5% decrease at 9 krpm, and no observable effect at 11 krpm. Pulsatility decreases with increased LVAD speed and MVR. The data indicate that a modest level of cardiac output (1.5-2 L/min) can be maintained by the native heart through the LVAD when the LVAD is off. These results demonstrate that MVR decreases the augmentation of forward flow by improved cardiac function at lower LVAD speeds. While some level of MVR can be tolerated in LVAD recipients, this condition represents a risk, particularly in those patients that undergo AVC closure, and may warrant repair at the time of surgery. PMID:27008972

  9. Gamma radiation and its role in bio prosthetic aortic valves implanted in rat hearts

    International Nuclear Information System (INIS)

    Porcine heart valves glutaraldehyde fixed are implanted in patients with valvular deterioration. Mineralization may be the major factor in the long-term failure of tissue bio prosthesis. Gamma radiation randomly breaks some glutaraldehyde cross-links. As a consequence of irradiation, the polymeric fibers belonging to the valvular tissue are broken too, leading to sites of collagen fiber disorganisation. It is well known that the collagen fibers may act as a passive nucleator of salts where the calcium phosphate salts precipitate. This salt concentration has been described in association with disintegrated sites of protein fiber, which may favour new sites where the calcium salts would be deposit. The irradiation process is a technique used for sterilization of porcine heart valve. The main objective of this work was to study the effect of different doses of gamma radiation on the calcification process of subcutaneously implanted valves in rats. Small pieces from glutaraldehyde fixed valves, irradiated to different doses with a 60Co sources were implanted subcutaneously in rats. The calcium was measured by X-ray and atomic absorption spectrophotometry. In our experimental conditions and at the radiation doses used in these tests, the calcium measurements on control and irradiated material were not significantly different. We conclude that, at the employed doses, the gamma radiation does not alter the process. (author)

  10. Simulation of Exercise-Induced Syncope in a Heart Model with Severe Aortic Valve Stenosis

    OpenAIRE

    Matjaž Sever; Samo Ribarič; Marjan Kordaš

    2012-01-01

    Severe aortic valve stenosis (AVS) can cause an exercise-induced reflex syncope (RS). The precise mechanism of this syncope is not known. The changes in hemodynamics are variable, including arrhythmias and myocardial ischemia, and one of the few consistent changes is a sudden fall in systemic and pulmonary arterial pressures (suggesting a reduced vascular resistance) followed by a decline in heart rate. The contribution of the cardioinhibitory and vasodepressor components of the RS to hemodyn...

  11. Oral surgery use of tachocomb in anticoagulated prosthetic heart valves patients

    OpenAIRE

    Dimova, Cena; Papakoca, Kiro; Kocev, Pavle; Milosev, Vladimir; Evrosimovska, Biljana

    2014-01-01

    The individuals with implanted prosthetic heart valves (PHV) belong in the group of patients with high risk from several aspects. Medical risk assessment of these patients consists of three segments: 1. cardiac function and safe dental and oral surgery treatment, 2. existing risk of potential development and prevention from infective endocarditis, and 3. the potential for altered hemostasis in patients prescribed anticoagulant medications. The aim of this study was to show the specific or...

  12. Component development of ''TORES'' for artificial heart device

    International Nuclear Information System (INIS)

    The Turbine Organic Rankine Engine System (TORES) consists of a hybrid heat engine capable of generating both hydraulic and electric power. The hydraulic power is used to drive the actuator of a prototype H-TAH blood pump and is generated by a centrifugal pump driven by a radial-inflow, Banki-type turbine using an organic Rankine cycle operating mode. Electric power, required only to operate the valves and controls of the hydraulic control system, is generated by a small, static, thermoelectric generator (TEG). The component test results are described for the breadboard version of the TORES. This development effort is a continuation of the Phase I program conducted under the sponsorship of the Cardiovascular Devices Branch of the National Heart and Lung Institute. In general, the performance levels achieved by the TORES components (i.e., turbine, pump, bearings, exchangers, hydraulic controls) were sufficiently high to more than meet the Phase I development goal of providing a minimum of 4 watts of hydraulic output to the H-TAH blood pump when utilizing a simulated 50 watt thermal heat source. The test results not only confirmed the adequacy of the performance of the TORES, but also provided the data needed for further optimization and miniaturization of the future integrated implantable prototype version to be implemented during Phase II of this program

  13. A unique, efficient, implantable, electromechanical, total artificial heart.

    Science.gov (United States)

    Takatani, S; Shiono, M; Sasaki, T; Sakuma, I; Glueck, J; Sekela, M; Noon, G; Nose, Y; DeBakey, M

    1991-01-01

    A completely implantable, one piece electromechanical total artificial heart (TAH) intended for permanent human use was developed. It consisted of left and right conically shaped pusher-plate blood pumps sandwiching a thin centerpiece with a compact, efficient electromechanical actuator. The actuator consisted of a direct current brushless motor; a planetary roller screw fit the space between the two conically shaped pusher-plates. The rotational motion of the motor was converted to the rectilinear motion of the rollerscrew to displace the left and right pusher-plates in the left master alternate mode. The diameter of the assembled TAH was 97 mm, with a central thickness of 82 mm. The overall weight was 620 g, with a displaced volume of 510 ml. The pump provided flows of 3-8 L/min with a preload of 1-15 mmHg against an afterload of 100 mmHg. The net efficiency ranged from 15% to 18%. This model showed good fit in the pericardial space of heart transplant recipients (body weight, 77 kg). PMID:1751127

  14. Rheumatic heart disease- a study of surgically excised cardiac valves and biopsies

    International Nuclear Information System (INIS)

    Objective: To examine the prevalence, age, sex and topographical distribution of the rheumatic heart diseases and its morphology. Design: A cross sectional descriptive study. Place and Duration of Study: Pathology Department, Army Medical College, Rawalpindi between 1981-1990. Patients and Methods: Five hundred and twenty six surgically excised cardiac valves and biopsies were studied in the laboratory in the light of clinical data. Results: Carditis constituted 87.4 % of the cardiac valvular disease with 23.5% active and 71% healed rheumatic lesions. About 5.5% had morphological appearances consistent with RHD. The lesions affected mitral valves (37.0%), aortic valve (22.1%), mitral and aortic valves together (21.0%) and atrial appendages (19.0%). Presentation was mostly as mitral stenosis either isolated (49.2% ) or combined (31.0%), aortic stenosis (11.7% ) and aortic incompetence with regurgitation (7.3%). Conclusion: Rheumatic carditis constitutes a significant proportion of cardiac valvular disease and affects comparatively younger age, with slight male preponderance and primarily affects mitral valve. (author)

  15. Mitigation of Shear-Induced Blood Damage of Mechanical Bileaflet Heart Valves using Embedded Vortex Generators

    Science.gov (United States)

    Hidalgo, Pablo; Arjunon, Sivakkumar; Saikrishnan, Neelakantan; Yoganathan, Ajit; Glezer, Ari

    2012-11-01

    The strong transitory shear stress generated during the time-periodic closing of the mechanical prosthetic bileaflet aortic heart valve, is considered to be one of the main factors responsible for complications, associated with thrombosis and thromboembolism. These flow transients are investigated using phase and time-averaged PIV in a low-volume (about 150 ml) test setup that simulates the pulsatile physiological conditions associated with a 23 mm St. Jude Medical valve. The PIV measurements are accompanied by continuous monitoring of the ventricular and aortic pressures and valve flow rate. Following the valve closure, the leakage flow between the valve leaflets is caused by the pressure buildup across the leaflets, leading to the formation of a regurgitation jet starting from the BMHV B-datum line. As in a typical starting jet, a counter-rotating vortex pair is formed along each leaflet edge and the vorticity sheet is associated with high shear stress that may be result in blood platelet activation. The present investigation demonstrates that the placement of arrays of mm-scale vortex generators near the edges of the leaflets diffuses the vortex sheet and suppresses the formation of these vortices, weakening the local velocity gradients and small-scale vortical structures. Supported by NIH and NSF.

  16. Right ventricular Hemodynamic Alteration after Pulmonary Valve Replacement in Children with Congenital Heart Disease

    Directory of Open Access Journals (Sweden)

    Hamid Bigdelian

    2015-03-01

    Full Text Available Introduction:  In patients who underwent surgery to repair Tetralogy of Fallot, right ventricular dilation from pulmonary regurgitation may be result in right ventricular failure, arrhythmias and cardiac arrest. Hence, pulmonary valve replacement may be necessary to reduce right ventricular volume overload. The aim of present study was to assess the effects of pulmonary valve replacement on right ventricular function after repair of Tetralogy of Fallot.   Materials and  Method:  This retrospective study was carried out between July 2011 and October 2013 on 21 consecutive patients in Chamran Heart Center (Esfahan. The study included 13 male (61.9% and 8 female (38.1%. Cardiac magnetic resonance was performed before, 6 and 12 months after pulmonary valve replacement in all patients (Babak Imaging Center, Tehran with the 1.5 Tesla system. The main reason for surgery at Tetralogy of Fallot repaired time was Tetralogy of Fallot + Pulmonary insufficiency (17 cases and Tetralogy of Fallot + Pulmonary atresia (4 cases. Right ventricular function was assessed before and after pulmonary valve replacement with Two-dimensional echocardiography and ttest was used to evaluate follow-up data.   Results:  Right ventricular end-diastolic volume, right ventricular end- systolic volume significantly decreased (P value ˂ 0.05.Right ventricular ejection fraction had a significant increase (P value ˂ 0.05. Right ventricular mass substantially shrank after pulmonary valve replacement. Moreover, pulmonary regurgitation noticeably decreased in patients. The other hemodynamic parameter such as left ventricular ejection fraction improved but was not significant (P value= 0.79. Conclusion:  Pulmonary valve replacement can successfully restores the impaired hemodynamic function of right ventricle which is caused by direct consequence of volume unloading in patient. Pulmonary valve surgery in children with Tetralogy of Fallot who have moderate to severe pulmonary

  17. Self-management of oral anticoagulant therapy for mechanical heart valve patients

    DEFF Research Database (Denmark)

    Christensen, Thomas D; Attermann, Jørn; Pilegaard, Hans K;

    2001-01-01

    Objective: Self-management of oral anticoagulant therapy (OAT) has shown good results on a short-term basis. We hypothesize that self-management of OAT provides a better quality of treatment than conventional management also on a long-term basis. The aim of this study was to assess the quality of...... self-management of OAT in patients with mechanical heart valve prostheses on a 4-year perspective in a prospective, non-randomized study. Design: Twenty-four patients with mechanical heart valves and on self-managed OAT were followed for up to 4 years. A matched, retrospectively selected group of...... conventionally managed heart valve patients (control group) was used as reference. Results: The median observation time was 1175 days (range: 174–1428 days). The self-managed patients were within therapeutic INR target range for a mean of 78.0% (range: 36.1%–93.9%) of the time compared with 61.0% (range 37...

  18. In vitro assessment of mitral valve function in cyclically pressurized porcine hearts.

    Science.gov (United States)

    Vismara, Riccardo; Leopaldi, Alberto M; Piola, Marco; Asselta, Chiara; Lemma, Massimo; Antona, Carlo; Redaelli, Alberto; van de Vosse, Frans; Rutten, Marcel; Fiore, Gianfranco B

    2016-04-01

    Recent approaches to the in vitro experimental study of cardiac fluid mechanics involve the use of whole biological structures to investigate in the lab novel therapeutic approaches for the treatment of heart pathologies. To enhance reliability and repeatability, the influence of the actuation strategy of the experimental apparatuses on the biomechanics of biological structures needs to be assessed. Using echography and intracardiac high-speed imaging, we compared the mitral valve (MV) anatomo-functional features (coaptation areas/lengths, papillary muscles-valvular plane distances) in two passive-beating-heart mock loops with internal (IPML) or external (EPML) pressurization of the ventricular chamber. Both apparatuses showed fluid dynamic conditions that closely resembled the physiology. The MVs analyzed in the EPML presented coaptation areas and lengths that were systematically higher, and exhibited greater variability from early-to peak-systole, as compared to those in the IPML. Moreover, in the EPML, the MV leaflets exhibited a convexity with high curvature toward the atrium. With the IPML, MV coaptation lengths ranged similar to available clinical data and the papillary muscles-valve plane distances were more stable throughout systole. In conclusion, both the apparatuses allow for reproducing in vitro the left heart hemodynamics, in terms of flow rates and pressures, with proper mitral valve continence. Results suggest that the IPML is more suitable for replicating the physiological MV functioning, while the EPML may have more potential as a model for the study of MV pathologies. PMID:26908180

  19. Impact of Detergent-Based Decellularization Methods on Porcine Tissues for Heart Valve Engineering.

    Science.gov (United States)

    Roosens, Annelies; Somers, Pamela; De Somer, Filip; Carriel, Victor; Van Nooten, Guido; Cornelissen, Ria

    2016-09-01

    To date an optimal decellularization protocol of heart valve leaflets (HVL) and pericardia (PER) with an adequate preservation of the extracellular matrix (ECM) is still lacking. This study compares a 4 day Triton X-100-based protocol with faster SDC-based protocols for the decellularization of cardiac tissues. Decellularized and non-treated HVL and PER were processed for histological, biochemical and mechanical analysis to determine the effect of these agents on the structure, ECM components, and biomechanical properties. Tissues treated with SDC-based protocols still showed nuclear material, whereas tissues treated with Triton X-100 1% + ENZ ± TRYP were completely cell free. For both decellularized tissues, an almost complete washout of glycosaminoglycans, a reduction of soluble collagen and an alteration of the surface ultrastructure was observed. Interestingly, only the elastic fibers of pericardial tissue were affected and this tissue had a decreased maximum load. This study showed that both detergents had a similar impact on the ECM. However, Triton X-100 1% +DNase/RNase (ENZ) ± Trypsin (TRYP) is the only protocol that generated completely cell free bioscaffolds. Also, our study clearly demonstrated that the decellularization agents have more impact on pericardial tissues than on heart valve leaflets. Thus, for the purpose of tissue engineering of heart valves, it is advisable to use valvular rather than pericardial matrices. PMID:26842626

  20. Age-Dependent Changes in Geometry, Tissue Composition and Mechanical Properties of Fetal to Adult Cryopreserved Human Heart Valves.

    Science.gov (United States)

    van Geemen, Daphne; Soares, Ana L F; Oomen, Pim J A; Driessen-Mol, Anita; Janssen-van den Broek, Marloes W J T; van den Bogaerdt, Antoon J; Bogers, Ad J J C; Goumans, Marie-José T H; Baaijens, Frank P T; Bouten, Carlijn V C

    2016-01-01

    There is limited information about age-specific structural and functional properties of human heart valves, while this information is key to the development and evaluation of living valve replacements for pediatric and adolescent patients. Here, we present an extended data set of structure-function properties of cryopreserved human pulmonary and aortic heart valves, providing age-specific information for living valve replacements. Tissue composition, morphology, mechanical properties, and maturation of leaflets from 16 pairs of structurally unaffected aortic and pulmonary valves of human donors (fetal-53 years) were analyzed. Interestingly, no major differences were observed between the aortic and pulmonary valves. Valve annulus and leaflet dimensions increase throughout life. The typical three-layered leaflet structure is present before birth, but becomes more distinct with age. After birth, cell numbers decrease rapidly, while remaining cells obtain a quiescent phenotype and reside in the ventricularis and spongiosa. With age and maturation-but more pronounced in aortic valves-the matrix shows an increasing amount of collagen and collagen cross-links and a reduction in glycosaminoglycans. These matrix changes correlate with increasing leaflet stiffness with age. Our data provide a new and comprehensive overview of the changes of structure-function properties of fetal to adult human semilunar heart valves that can be used to evaluate and optimize future therapies, such as tissue engineering of heart valves. Changing hemodynamic conditions with age can explain initial changes in matrix composition and consequent mechanical properties, but cannot explain the ongoing changes in valve dimensions and matrix composition at older age. PMID:26867221

  1. First North American 50 cc Total Artificial Heart Experience: Conversion from a 70 cc Total Artificial Heart.

    Science.gov (United States)

    Khalpey, Zain; Kazui, Toshinobu; Ferng, Alice S; Connell, Alana; Tran, Phat L; Meyer, Mark; Rawashdeh, Badi; Smith, Richard G; Sweitzer, Nancy K; Friedman, Mark; Lick, Scott; Slepian, Marvin J; Copeland, Jack G

    2016-01-01

    The 70 cc total artificial heart (TAH) has been utilized as bridge to transplant (BTT) for biventricular failure. However, the utilization of 70 cc TAH has been limited to large patients for the low output from the pulmonary as well as systemic vein compression after chest closure. Therefore, the 50 cc TAH was developed by SynCardia (Tucson, AZ) to accommodate smaller chest cavity. We report the first TAH exchange from a 70 to 50 cc due to a fit difficulty. The patient failed to be closed with a 70 cc TAH, although the patient met the conventional 70 cc TAH fit criteria. We successfully closed the chest with a 50 cc TAH. PMID:26809081

  2. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    OpenAIRE

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

    2011-01-01

    Objectives Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. Methods A Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stati...

  3. Double Valve Replacement (Mitral and Aortic for Rheumatic Heart Disease: A 20-year experience with 300 patients.

    Directory of Open Access Journals (Sweden)

    Prashant Mishra

    2016-09-01

    Full Text Available Introduction: Rheumatic heart disease still remains one of the leading causes of congestive heart failure and death owing to valvular pathologies, in developing countries. Valve replacement still remains the treatment of choice in such patients.The aim of this study wasto analyze the postoperative outcome of  double valve replacement (Mitral and Aortic in patients of rheumatic heart disease. Materials and Methods: Between 1988 and 2008, 300 patients of rheumatic heart disease underwent double (Mitral and Aortic valve replacement with Starr Edwards valve or St Jude mechanical valve prosthesis were implanted. These patients were studied retrospectively for preoperative data and postoperative outcome including causes of early and late deaths and the data was analyzed statistically. Results: The 30-day hospital death rate was 11.3% andlate death occurred in 11.6%. Anticoagulant regimen was followed to maintain the target pro-thrombin time at 1.5 times the control value. The actuarial survival (exclusive of hospital mortality was 92.4%, 84.6%, and 84.4%, per year at 5, 10, and 20 years, respectively Conclusions: In view of the acknowledged advantageof superior durability, increased thromboresistance in our patient population, and its cost effectiveness the Starr-Edwards ball valve or St. Jude valve is the mechanical prosthesis of choice for advanced combined valvular disease. The low-intensity anticoagulant regimen has offered suffcient protection against thromboembolism as well as hemorrhage.

  4. Decellularized GGTA1-KO pig heart valves do not bind preformed human xenoantibodies.

    Science.gov (United States)

    Ramm, Robert; Niemann, Heiner; Petersen, Björn; Haverich, Axel; Hilfiker, Andres

    2016-07-01

    Pre-clinical and clinical data have unequivocally demonstrated the usefulness of decellularized heart valve (HV) matrices implanted for HV replacement therapy. However, human donor valves applicable for decellularization are in short supply, which prompts the search for suitable alternatives, such as porcine grafts. Since decellularization might be insufficient to remove all xenoantigens, we analysed the interaction of human preformed antibodies with decellularized porcine HV in vitro to assess potential immune reactions upon implantation. Detergent-decellularized pulmonary HV from German Landrace wild-type (wt) or α1,3-galactosyltransferase knockout (GGTA1-KO) pigs were investigated by inhibition ELISA and GSL I-B4 staining to localize and quantify matrix-bound αGal epitopes, which represent the most prominent xenoantigen. Additionally, preformed human xenoantibodies were affinity purified by perfusing porcine kidneys. Binding of purified human antibodies to decellularized HV was investigated by inhibition ELISA. Furthermore, binding of human plasma proteins to decellularized matrices was determined by western blot. Decellularized human pulmonary artery served as controls. Decellularization of wt HV led to a reduction of αGal epitopes by 70 %. Residual epitopes were associated with the subendothelial extracellular matrix. As expected, no αGal epitopes were found on decellularized GGTA1-KO matrix. The strongest binding of preformed human anti-pig antibodies was found on wt matrices, whereas GGTA1-KO matrices bound similar or even fewer xenoantibodies than human controls. These results demonstrate the suitability of GGTA1-KO pigs as donors for decellularized heart valves for human patients. Besides the presence of αGal antibodies on decellularized heart valves, no further preformed xenoantibodies against porcine matrix were detected in tested human sera. PMID:27154491

  5. Age-Dependent Changes in Geometry, Tissue Composition and Mechanical Properties of Fetal to Adult Cryopreserved Human Heart Valves

    Science.gov (United States)

    van Geemen, Daphne; Soares, Ana L. F.; Oomen, Pim J. A.; Driessen-Mol, Anita; Janssen-van den Broek, Marloes W. J. T.; van den Bogaerdt, Antoon J.; Bogers, Ad J. J. C.; Goumans, Marie-José T. H.; Baaijens, Frank P. T.; Bouten, Carlijn V. C.

    2016-01-01

    There is limited information about age-specific structural and functional properties of human heart valves, while this information is key to the development and evaluation of living valve replacements for pediatric and adolescent patients. Here, we present an extended data set of structure-function properties of cryopreserved human pulmonary and aortic heart valves, providing age-specific information for living valve replacements. Tissue composition, morphology, mechanical properties, and maturation of leaflets from 16 pairs of structurally unaffected aortic and pulmonary valves of human donors (fetal-53 years) were analyzed. Interestingly, no major differences were observed between the aortic and pulmonary valves. Valve annulus and leaflet dimensions increase throughout life. The typical three-layered leaflet structure is present before birth, but becomes more distinct with age. After birth, cell numbers decrease rapidly, while remaining cells obtain a quiescent phenotype and reside in the ventricularis and spongiosa. With age and maturation–but more pronounced in aortic valves–the matrix shows an increasing amount of collagen and collagen cross-links and a reduction in glycosaminoglycans. These matrix changes correlate with increasing leaflet stiffness with age. Our data provide a new and comprehensive overview of the changes of structure-function properties of fetal to adult human semilunar heart valves that can be used to evaluate and optimize future therapies, such as tissue engineering of heart valves. Changing hemodynamic conditions with age can explain initial changes in matrix composition and consequent mechanical properties, but cannot explain the ongoing changes in valve dimensions and matrix composition at older age. PMID:26867221

  6. Demikhov's "Mechanical Heart": The Circumstances Surrounding Creation of the World's First Implantable Total Artificial Heart in 1937.

    Science.gov (United States)

    Glyantsev, Sergey P; Tchantchaleishvili, Vakhtang; Bockeria, Leo A

    2016-01-01

    The world's first implantable total artificial heart was designed by Vladimir Demikhov as a fourth year biology student in Voronezh, Soviet Union, in 1937. As a prototype of his device, Demikhov must have used an apparatus for extracorporeal blood circulation invented by Sergei Bryukhonenko of Moscow. The device was the size of a dog's native heart and consisted of two diaphragm pumps brought into motion by an electric motor. A dog with an implanted device lived for 2.5 hours. In addition to having the prototype, the preconditions for Demikhov's artificial heart creation were his manual dexterity, expertise in animal physiology, and his mechanistic worldview. PMID:26501917

  7. Heart valve surgery in hemodialysis-dependent patients: nutrition status impact on surgical outcome.

    Science.gov (United States)

    Kawahito, Koji; Aizawa, Kei; Oki, Shinichi; Saito, Tsutomu; Misawa, Yoshio

    2016-06-01

    Valve surgery in hemodialysis-dependent patients is associated with postoperative complications and a high mortality rate, and such patients frequently suffer cachexia. This study aimed to determine pre- and intraoperative risk factors associated with in-hospital mortality and long-term survival in hemodialysis-dependent patients undergoing heart valve surgery from the viewpoint of nutrition status. Eighty-seven hemodialysis-dependent patients who underwent valve surgery between January 1998 and October 2015 were retrospectively reviewed. Thirty-seven potential perioperative risk factors were evaluated. The in-hospital mortality rate was 12.6 % (11 patients). Univariate analysis identified New York Heart Association Functional Classification III or IV, emaciation (body mass index 3000 ml as predictors of in-hospital death. Multivariate logistic regression analysis confirmed low serum albumin death. The 1- and 3-year actuarial survival rates were 64.9 ± 5.4 and 51.8 ± 5.8 %, respectively. Long-term survival estimated by log-rank test was negatively impacted by anemia (hemoglobin death. Hypoalbuminemia and emergent/urgent operation are strong predictors of in-hospital and remote death. Malnutrition before surgery should be considered for operative risk estimation, and adequate preoperative nutrition management may improve surgical outcomes for hemodialysis-dependent patients. PMID:26749145

  8. Bioreactor Conditioning for Accelerated Remodeling of Fibrin-Based Tissue Engineered Heart Valves

    Science.gov (United States)

    Schmidt, Jillian Beth

    Fibrin is a promising scaffold material for tissue engineered heart valves, as it is completely biological, allows for engineered matrix alignment, and is able to be degraded and replaced with collagen by entrapped cells. However, the initial fibrin matrix is mechanically weak, and extensive in vitro culture is required to create valves with sufficient mechanical strength and stiffness for in vivo function. Culture in bioreactor systems, which provide cyclic stretching and enhance nutrient transport, has been shown to increase collagen production by cells entrapped in a fibrin scaffold, accelerating strengthening of the tissue and reducing the required culture time. In the present work, steps were taken to improve bioreactor culture conditions with the goal of accelerating collagen production in fibrin-based tissue engineered heart valves using two approaches: (i) optimizing the cyclic stretching protocol and (ii) developing a novel bioreactor system that permits transmural and lumenal flow of culture medium for improved nutrient transport. The results indicated that incrementally increasing strain amplitude cyclic stretching with small, frequent increments in strain amplitude was optimal for collagen production in our system. In addition, proof of concept studies were performed in the novel bioreactor system and increased cellularity and collagen deposition near the lumenal surface of the tissue were observed.

  9. Effect of vortex generators on the closing transient flow of bileaflet mechanical heart valves

    Science.gov (United States)

    Murphy, David; Dasi, Lakshmi; Yoganathan, Ajit; Glezer, Ari

    2006-11-01

    The time-periodic closing of bileaflet mechanical heart valves is accompanied by a strong flow transient that is associated with the formation of a counter-rotating vortex pair near the b-datum line of leaflet edges. The strong transitory shear that is generated by these vortices may be damaging to blood elements and may result in platelet activation. In the present work, these flow transients are mitigated using miniature vortex generator arrays that are embedded on the surface of the leaflets. Two vortex generator designs were investigated: one design comprised staggered rectangular fins and the other one staggered hemispheres. The closing transients in the absence and presence of the passive vortex generators are characterized using phase locked PIV measurements. The study utilizes a 25 mm St. Jude Medical valve placed in the aortic position of the Georgia Tech left heart simulator. Measurements of the velocity field in the center plane of the leaflets demonstrate that the dynamics of the transient vortices that precede the formation of the leakage jets can be significantly altered and controlled by relatively simple passive modifications of existing valve designs. Human blood experiments validated the effectiveness of miniature vortex generators in reducing thrombus formation by over 42 percent.

  10. A numerical investigation of blood damage in the hinge area of bileaflet mechanical heart valves

    Science.gov (United States)

    Yun, Min; Wu, Jingshu; Simon, Helene; Sotiropoulos, Fotis; Aidun, Cyrus; Yoganathan, Ajit

    2010-11-01

    Studies have shown that high shear stress and large recirculation regions have a strong impact on thromboembolic complications in Bileaflet mechanical heart valves (BMHV). This study quantitatively compares the hinge flow field and blood damage of the 23mm St. Jude Medical (SJM) regent with different hinge gap widths and the 23mm CarboMedics (CM) valves. The lattice-Boltzmann method with external boundary force (LBM-EBF) [Wu and Aidun, Int. J Num. Methods Fluids, 62, 7, 2009] was implemented to simulate the flow and capture the dynamics and the surface shear stress of the platelets with realistic geometry. The velocity boundary conditions for the small-scale hinge flow are obtained from previous 3D large-scale computational fluid dynamics (CFD) simulations [Simon et al, Annals of Biomedical Engineering, 38, 3, 2009]. The flow patterns of three hinges that were studied were similar during diastole. However, velocity magnitudes and shear stresses at the hinge gap were different, which may explain the higher blood damage index (BDI) value for the CM valve and lower BDI value for the SJM valve with a larger gap width. The multiscale computational method used to quantitatively measure the BDI during a full cardiac cycle will be discussed.

  11. Reconstructed image of human heart for total artificial heart implantation, based on MR image and cast silicone model of heart

    International Nuclear Information System (INIS)

    Based on transverse (TRN) and LV long axis (LAX) MR images of two cadaver hearts, three-dimensional (3-D) computer models of the connecting interface between remaining heart and total artificial heart, i.e., mitral and tricuspid valvular annuli (MVA and TVA), ascending aorta (Ao) and pulmonary artery (PA), were reconstructed to compare the shape and the size of MVA and those of TVA, the distance between the center of MVA and TVA (DG), the angle between the plane of MVA and that of TVA (RT), and the angles of Ao and PA, respectively, to the plane of MVA (RA, RP), with those obtained in cast silicone models. It was found that based on LAX rather than TRN MR image, MVA and TVA might be more precisely reconstructed. The data obtained in 3-D images of MVA, TVA, Ao and PA based on silicone models of 32 hearts were as follows: DG (cm): 4.17±0.43, RT (degrees): 22.1±11.3, RA (degrees): 54.9±15.3, RP (degrees): 30.8±17.1. (author)

  12. Reconstructed image of human heart for total artificial heart implantation, based on MR image and cast silicone model of heart

    Energy Technology Data Exchange (ETDEWEB)

    Komoda, Takashi; Maeta, Hajime (Kagawa Medical School, Miki (Japan)); Uyama, Chikao

    1991-03-01

    Based on transverse (TRN) and LV long axis (LAX) MR images of two cadaver hearts, three-dimensional (3-D) computer models of the connecting interface between remaining heart and total artificial heart, i.e., mitral and tricuspid valvular annuli (MVA and TVA), ascending aorta (Ao) and pulmonary artery (PA), were reconstructed to compare the shape and the size of MVA and those of TVA, the distance between the center of MVA and TVA (D{sub G}), the angle between the plane of MVA and that of TVA (R{sub T}), and the angles of Ao and PA, respectively, to the plane of MVA (R{sub A}, R{sub P}), with those obtained in cast silicone models. It was found that based on LAX rather than TRN MR image, MVA and TVA might be more precisely reconstructed. The data obtained in 3-D images of MVA, TVA, Ao and PA based on silicone models of 32 hearts were as follows: D{sub G} (cm): 4.17+-0.43, R{sub T} (degrees): 22.1+-11.3, R{sub A} (degrees): 54.9+-15.3, R{sub P} (degrees): 30.8+-17.1. (author).

  13. Detection of Heart Diseases by Mathematical Artificial Intelligence Algorithm Using Phonocardiogram Signals

    OpenAIRE

    D. Prakash; T. Uma Mageshwari; K. Prabakaran; A. Suguna

    2013-01-01

    An artificial intelligence (AI) algorithm has been developed using Mathematical formula to diagnose heart disease from Phonocardiogram (PCG) signals. Auscultation, the technique of listening to heart sounds with a stethoscope can be used as a primary detection technique for detecting heart disorders for the past years. But now the Phonocardiogram, the digital recording of heart sounds is becoming very popular technique as it is relatively inexpensive. Four amplitude parameters of the PCG sign...

  14. Total Artificial Heart as Bridge to Heart Transplantation in Chagas Cardiomyopathy: Case Report.

    Science.gov (United States)

    Ruzza, A; Czer, L S C; De Robertis, M; Luthringer, D; Moriguchi, J; Kobashigawa, J; Trento, A; Arabia, F

    2016-01-01

    Chagas disease (CD) is becoming an increasingly recognized cause of dilated cardiomyopathy outside of Latin America, where it is endemic, due to population shifts and migration. Heart transplantation (HTx) is a therapeutic option for end-stage cardiomyopathy due to CD, but may be considered a relative contraindication due to potential reactivation of the causative organism with immunosuppression therapy. The total artificial heart (TAH) can provide mechanical circulatory support in decompensated patients with severe biventricular dysfunction until the time of HTx, while avoiding immunosuppressive therapy and removing the organ most affected by the causative organism. We report herein a patient with CD and severe biventricular dysfunction, who had mechanical circulatory support with a TAH for more than 6 months, followed by successful orthotopic HTx and treatment with benznidazole for 3 months. The patient had no evidence of recurrent disease in the transplanted heart based on endomyocardial biopsy up to 1 year post-transplantation, and remains alive more than 30 months after insertion of a TAH and 24 months after HTx. PMID:26915885

  15. Development of an Electrohydraulic Total Artificial Heart System

    Science.gov (United States)

    Homma, Akihiko; Taenaka, Yoshiyuki; Tatsumi, Eisuke; Takewa, Yoshiaki; Mizuno, Toshihide; Shioya, Kyoko; Lee, Hwan Sung; Tsukiya, Tomonori; Kakuta, Yukihide; Katagiri, Nobumasa; Nishinaka, Tomohiro; Koshiji, Kohji

    An electrohydraulic total artificial heart (EHTAH) system has been developed. The EHTAH system consists of diaphragm-type blood pumps, an electrohydraulic actuator, an internal control unit, a transcutaneous energy transfer system (TETS), a transcutaneous optical telemetry system (TOTS), and an internal battery. The reciprocating rotation of the impeller generates oil pressure which drives the blood pumps at alternating intervals. The blood pumps and the actuator were successfully integrated into the pump unit without oil conduits. As a result of miniaturizing the blood pumps and the actuator, the displacement volume and weight of the EHTAH system decreased to 872 ml and 2492g, respectively. Furthermore, the maximum flow rate and efficiency increased up to 12 L/min and 15.4%. The pump units and the EHTAH systems were successfully implanted in 36 calves weighing from 55 to 87kg. In the longest case, the ca1f with the pump unit survived for 87 days and the calf with the EHTAH system survived for 70 days. The EHTAH system was powered by the TETS, and was powered everyday by the internal battery for 40 minutes. These results indicate that the EHTAH system has the potential to become a fully implantable cardiac replacement system.

  16. Development of a nuclear-powered artificial heart

    International Nuclear Information System (INIS)

    Of the few known methods of furnishing power for a completely implantable artificial heart one of the most promising involves the conversion of the thermal energy from the decay of man-made radioisotopes. Serious consideration of radioisotopic, or nuclear, heat sources for implantable power supplies began in early 1964. Since then there have been some notable accomplishments on the road to a nuclear-powered system but a large number of important and difficult problems remain to be clarified. The overall objective of the Atomic Energy Commission's current program is to examine critically these problems and to provide information so that the reasonableness and practicability of the nuclear approach can be assessed at an early date. Research and development projects are underway on radioisotope heat source fuel and containment materials, on a highly reliable, long-life thermal energy conversion system and its requisite high performance thermal insulation package, on the coupling of the converter output power to the diaphragm of a suitable blood pump in such a manner that the system is fully responsive to the needs of the body, and on the radiobiological implications of large-scale heat source implantation. (auth)

  17. Indium-111 labeled platelet survival time studies in patients with prosthetic heart valves

    International Nuclear Information System (INIS)

    Platelet survival time (PST) studies are useful to demonstrate whether or not patients with prosthetic heart valves have normal or shortened PST. During treatment for recurrent TIAs the PST will signal whether the patient is returning towards a normal PST. Using Indium-111 labeled platelets (ILP) the authors studied 10 patients suffering recurrent TIAs after prosthetic valve surgery to determine whether low dose aspirin increased their PST toward normal and whether the treatment had a beneficial effect on their TIA episodes. The authors conclude that low dose aspirin therapy as studied by ILP has no beneficial effect on PST or in preventing recurrent TIA. ILP is an important technique that allows the physician to identify those patients with shortened PST and to determine response to therapy

  18. Heart Rate Variability in Cavalier King Charles Spaniels with Different Degree of Myxomatous Mitral Valve Disease

    DEFF Research Database (Denmark)

    Rasmussen, Caroline Elisabeth; Falk, Bo Torkel; Zois, Nora Elisabeth; Moesgaard, Sophia Gry; Häggström, Jens; Pedersen, Henrik Duelund; Olsen, Lisbeth Høier

    2010-01-01

    variability (HRV). Reduced HRV is seen in dogs with heart failure secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease progression in dogs with early stages of MMVD. Comparable results are found in people with primary mitral valve prolapse, a disease...... resembling canine MMVD. Aim: To associate progression of MMVD in dogs with time and frequency domain HRV, analysed from 24-hour electrocardiography. Materials and Methods: Eighty-one Cavalier King Charles Spaniels (CKCS) were examined by echocardiography and 24-hour electrocardiography. CKCS were divided...... responsiveness. Results: Ten out of 13 HRV variables decreased with increasing MMVD severity. In group 1, 10 HRV variables were increased compared to group 3 and 4 (P<0.05) and 2 HRV variables were increased compared to group 2 (P<0.04). Eight and 10 HRV variables were increased in group 2 compared to group 3 (P...

  19. Mitigation of Shear-Induced Blood Damage by Mechanical Bileaflet Heart Valves

    Science.gov (United States)

    Zakharin, Boris; Arjunon, Sivakkumar; Saikrishnan, Neelakantan; Yoganathan, Ajit; Glezer, Ari

    2010-11-01

    The strong transitory shear stress generated during the time-periodic closing of bileaflet mechanical heart valves that is associated with the formation of counter-rotating vortices near the leaflet edges may be damaging to blood elements and may result in platelet activation and therefore thrombosis and thromboembolism complications. These flow transients are investigated using fluorescent PIV in a new, low-volume test setup that reproduces the pulsatile physiological conditions associated with a 25 mm St. Jude Medical valve. The flow transients are partially suppressed and the platelet activation is minimized using miniature vortex generator arrays that are embedded on the surface of the leaflets. Measurements of the ensuing flow taken phase-locked to the leaflet motion demonstrate substantial modification of the transient vertical structures and concomitant reduction of Reynolds shear stresses. Human blood experiments validated the effectiveness of miniature vortex generators in reducing thrombus formation by over 42 percent.

  20. Mitral Valve Disease

    Science.gov (United States)

    ... Tricuspid Valve Disease Cardiac Rhythm Disturbances Thoracic Aortic Aneurysm Pediatric and Congenital Heart Disease Heart abnormalities that are ... Transplantation End-stage Lung Disease Adult Lung Transplantation Pediatric Lung ... Aortic Aneurysm Mitral Valve Disease Overview The mitral valve is ...

  1. Development of a totally implantable electromechanical total artificial heart: Baylor TAH.

    Science.gov (United States)

    Takatani, S; Shiono, M; Sasaki, T; Glueck, J; Noon, G P; Nosé, Y; DeBakey, M E

    1992-08-01

    A totally implantable, one-piece, electrome-chanical total artificial heart (TAH) intended for permanent human use has been developed. It consists of left and right pusher-plate pumps (63 cc design stroke volume) sandwiching a thin center piece with a compact electromechanical actuator. The pusher-plates are shaped conically to accommodate an actuator in the space between them. The actuator consists of an efficient and durable planetary roller screw and direct current brushless motor. The left master alternate pumping mode was implemented utilizing the left pump pusher-plate position signal. The blood-contacting surface was coated with a dry gelatin to yield long-term clot-free performance. Trileaflet tissue valves of 27 and 23 mm are used in the inflow and outflow ports. The diameter and thickness of the TAH are 97 and 82 mm. the overall volume is 510 cc, and the weight is 620 g. Anatomic fit was confirmed in 26 heart transplant recipients (body weight 78 kg and surface area 2 m2) without compressing adjacent organs. The pump performance study revealed that the TAH can yield outputs of 3-8 L/min against the 100 mm Hg afterload with 1-10 mm Hg filling pressure. The input power to the motor ranged from 7 to 12 W, with an efficiency of 18% to 14%. A one-week in vivo calf study demonstrated adequate performance of the TAH, particularly the regulation of atrial pressures. Good anatomic fit and good biocompatibility were also demonstrated. PMID:10078282

  2. On-X Heart Valve Prosthesis: Numerical Simulation of Hemodynamic Performance in Accelerating Systole.

    Science.gov (United States)

    Mirkhani, Nima; Davoudi, Mohammad Reza; Hanafizadeh, Pedram; Javidi, Daryoosh; Saffarian, Niloofar

    2016-09-01

    Numerical simulation of the bileaflet mechanical heart valves (BMHVs) has been of interest for many researchers due to its capability of predicting hemodynamic performance. A lot of studies have tried to simulate this three-dimensional complex flow in order to analyze the effect of different valve designs on the blood flow pattern. However, simplified models and prescribed motion for the leaflets were utilized. In this paper, transient complex blood flow in the location of ascending aorta has been investigated in a realistic model by fully coupled simulation. Geometry model for the aorta and the replaced valve is constructed based on the medical images and extracted point clouds. A 23-mm On-X Medical BMHV as the new generation design has been selected for the flow field analysis. The two-way coupling simulation is conducted throughout the accelerating phase in order to obtain valve dynamics in the opening process. The complex flow field in the hinge recess is captured precisely for all leaflet positions and recirculating zones and elevated shear stress areas have been observed. Results indicate that On-X valve yields relatively less transvalvular pressure gradient which would lower cardiac external work. Furthermore, converging inlet leads to a more uniform flow and consequently less turbulent eddies. However, the leaflets cannot open fully due to middle diffuser-shaped orifice. In addition, asymmetric butterfly-shaped hinge design and converging orifice leads to better hemodynamic performance. With the help of two-way fluid solid interaction simulation, leaflet angle follows the experimental trends more precisely rather than the prescribed motion in previous 3D simulations. PMID:27164902

  3. Roentgenologic aspects of acute respiratory in sufficiency after heart valve prosthesis implantation

    International Nuclear Information System (INIS)

    Analysis of the X-ray findings in 156 patients with acute respiratory insufficiency (ART) in the immediate periods after implantation of heart valve prostheses has shown that various pulmonary complications, such as pulmonary edema (in 84% of cases), atelectasis, hypoventilation (5.1%), hemothorax (6.4%), pneumothorax (0.6%) were the prerequisites for the development of respiratory disorders. Pneumonias were not the primary cause of ART but an additional factor for the respiratory disorder progress, for they develop in the presence of previous pulmonary changes. The necessity and possibility of establishing the pathogenetic mechanism of pulmonary edema is shown

  4. An immersogeometric variational framework for fluid–structure interaction: application to bioprosthetic heart valves

    Science.gov (United States)

    Kamensky, David; Hsu, Ming-Chen; Schillinger, Dominik; Evans, John A.; Aggarwal, Ankush; Bazilevs, Yuri; Sacks, Michael S.; Hughes, Thomas J. R.

    2014-01-01

    In this paper, we develop a geometrically flexible technique for computational fluid–structure interaction (FSI). The motivating application is the simulation of tri-leaflet bioprosthetic heart valve function over the complete cardiac cycle. Due to the complex motion of the heart valve leaflets, the fluid domain undergoes large deformations, including changes of topology. The proposed method directly analyzes a spline-based surface representation of the structure by immersing it into a non-boundary-fitted discretization of the surrounding fluid domain. This places our method within an emerging class of computational techniques that aim to capture geometry on non-boundary-fitted analysis meshes. We introduce the term “immersogeometric analysis” to identify this paradigm. The framework starts with an augmented Lagrangian formulation for FSI that enforces kinematic constraints with a combination of Lagrange multipliers and penalty forces. For immersed volumetric objects, we formally eliminate the multiplier field by substituting a fluid–structure interface traction, arriving at Nitsche’s method for enforcing Dirichlet boundary conditions on object surfaces. For immersed thin shell structures modeled geometrically as surfaces, the tractions from opposite sides cancel due to the continuity of the background fluid solution space, leaving a penalty method. Application to a bioprosthetic heart valve, where there is a large pressure jump across the leaflets, reveals shortcomings of the penalty approach. To counteract steep pressure gradients through the structure without the conditioning problems that accompany strong penalty forces, we resurrect the Lagrange multiplier field. Further, since the fluid discretization is not tailored to the structure geometry, there is a significant error in the approximation of pressure discontinuities across the shell. This error becomes especially troublesome in residual-based stabilized methods for incompressible flow, leading

  5. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    Energy Technology Data Exchange (ETDEWEB)

    Symersky, Petr [Onze Lieve Vrouwe Gasthuis, Department of Cardiothoracic Surgery, Oosterpark 9, P.O box 95500, Amsterdam (Netherlands); Academic Medical Center, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); Budde, Ricardo P.J. [University Medical Center, Department of Radiology, Utrecht (Netherlands); Westers, Paul [Julius Center for Health Sciences and Primary Care, Department of Biostatistics, Utrecht (Netherlands); Mol, Bas A.J.M. de [Academic Medical Center, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); University of Technology Eindhoven, Department of Biomedical Engineering, Eindhoven (Netherlands); Prokop, Mathias [Radboud University Nijmegen Medical Center, Department of Radiology, Nijmegen (Netherlands)

    2011-10-15

    Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. A Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stationary and pulsatile conditions. Artifacts and radiopaque component volumes were quantified with thresholds based on surrounding structures and valvular components. Hypodense artifacts volumes (mm{sup 3}) were 1,029 {+-} 147, 535 {+-} 53, 371 {+-} 16, and 366 {+-} 18 for the SJM, MH, CM and ON-X valves (p < 0.001 except for the latter two valves p = 0.43). Hyperdense artifact volumes were 3,546 {+-} 141, 2,387 {+-} 103, 2,003 {+-} 102, and 3,033 {+-} 31 for the SJM, MH, CM and ON-X valve, respectively (all differences p < 0.001). Leaflet motion affected hypodense (F = 41.5, p < 0.001) and hyperdense artifacts (F = 53.7, p < 0.001). Closed and moving leaflets were associated with the least and the most artifacts respectively (p < 0.001, both artifact types). Both valve design and leaflet motion affect PHV-induced artifacts. Best imaging results may be expected for the CM valve during phases in which the leaflets are closed. (orig.)

  6. Methods for improved flexural mechanical properties of 3D-plotted PCL-based scaffolds for heart valve tissue engineering

    OpenAIRE

    Cardon, Ludwig; Ragaert, Kim; De Somer, Filip; Van de Velde, Stieven; Degrieck, Joris

    2015-01-01

    While porous PCL scaffolds can be manufactured trough 3D plotting with high regularity and reproducibility, it has been a challenge in previous research to mimick the highly flexible behaviour of the natural valve leaflets. In this study, an exploration is made of two separate approaches for the improved flexibility of 3D plotted poly--caprolactone (PCL) scaffolds for heart valve leaflets. Firstly, the scaffold geometry is radically altered towards a very open woven-like structure, by adequat...

  7. Methods for improved flexural mechanical properties of 3D-plotted PCL-based scaffolds for heart valve tissue engineering:

    OpenAIRE

    Cardon, Ludwig; De Somer, Filip; Degrieck, Joris; Ragaert, Kim; Van de Velde, Stieven

    2013-01-01

    While porous PCL scaffolds can be manufactured trough 3D plotting with high regularity and reproducibility, it has been a challenge in previous research to mimick the highly flexible behaviour of the natural valve leaflets. In this study, an exploration is made of two separate approaches for the improved flexibility of 3D plotted poly--caprolactone (PCL) scaffolds for heart valve leaflets. Firstly, the scaffold geometry is radically altered towards a very open woven-like structure, by adequat...

  8. Blood Damage Through a Bileaflet Mechanical Heart Valve: A Quantitative Computational Study Using a Multiscale Suspension Flow Solver

    OpenAIRE

    Min Yun, B.; Aidun, Cyrus K.; Yoganathan, Ajit P.

    2014-01-01

    Bileaflet mechanical heart valves (BMHVs) are among the most popular prostheses to replace defective native valves. However, complex flow phenomena caused by the prosthesis are thought to induce serious thromboembolic complications. This study aims at employing a novel multiscale numerical method that models realistic sized suspended platelets for assessing blood damage potential in flow through BMHVs. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow th...

  9. Assessment of the interface of beating heart with total artificial heart using magnetic resonance imaging

    International Nuclear Information System (INIS)

    We have studied three-dimensionally (3-D) reconstructed images of atrioventricular (AV) annuli based on four-chamber magnetic resonance (MR) images for total artificial heart (TAH) implantation. To assess the interrelationship among the AV annuli and the thorax, we applied the frame of reference of the vertebral canal to these images. The Z-axis was along the vertebral canal, the Y-axis in the anteroposterior direction. The angle alpha was defined as the angle between the X-axis and the intersection between the plane of the annulus and the X-Y plane. The angle beta was defined as the angle between the Z-axis and the intersection between the plane of annulus and X-Z plane. The angle gamma was defined as the angle between the plane of the annulus and the anterior thoracic wall. We determined each angle for the mitral annulus (MVA) and tricuspid annulus (TVA) in four normal subjects to be as follows: alpha-MVA, 20.5-39.5 degrees; alpha-TVA, 26.1-43.5 degrees; beta-MVA, 4.7-49.4 degrees; beta-TVA, 4.4-40.9 degrees; and gamma-TVA, 35.2-44.1 degrees. It is suggested that reconstruction of the thoracic wall and AV annuli using the frame of reference of the diaphragmatic surface of the heart would facilitate evaluation of the spacial requirements for TAH implantation. Research to define this new frame of reference is in progress. (author)

  10. Valve Replacement Performed on the Beating Heart with Continuous Retrograde Coronary Sinus Isothermic Blood Perfusion Combined with Coronary Bypass

    Directory of Open Access Journals (Sweden)

    Orhan Saim Demirtürk

    2012-12-01

    Full Text Available An operation on the beating heart was planned for a 60-year-old woman who applied to our clinic with aortic stenosis, three vessel coronary artery disease and poor left ventricular function. There are reports about beating heart valve surgery perfomed alone or combined with coronary artery bypass operations using continuous retrograde coronary sinus isothermic blood perfusion in patients with poor ventricle. We performed a coronary revascularization process for three-vessel disease on the pump beating heart and aortic valve replacement under cross-clamp using continuous retrograde coronary sinus isothermic blood perfusion in the same session. She was discharged on the sixth postoperative day after an uneventful recovery. She is well and active 24 months after the operation. Valve replacement using the retrograde coronary sinus isothermic blood perfusion technique due to its protective effect on the already borderline myocardial functions in patients with poor ventricles is a useful and clinically successful method.

  11. Molecular Analysis of Oral Bacteria in Heart Valve of Patients With Cardiovascular Disease by Real-Time Polymerase Chain Reaction.

    Science.gov (United States)

    Oliveira, Francisco Artur Forte; Forte, Clarissa Pessoa Fernandes; Silva, Paulo Goberlânio de Barros; Lopes, Camile B; Montenegro, Raquel Carvalho; Santos, Ândrea Kely Campos Ribeiro Dos; Sobrinho, Carlos Roberto Martins Rodrigues; Mota, Mário Rogério Lima; Sousa, Fabrício Bitu; Alves, Ana Paula Negreiros Nunes

    2015-11-01

    Structural deficiencies and functional abnormalities of heart valves represent an important cause of cardiovascular morbidity and mortality, and a number of diseases, such as aortic stenosis, have been recently associated with infectious agents. This study aimed to analyze oral bacteria in dental plaque, saliva, and cardiac valves of patients with cardiovascular disease. Samples of supragingival plaque, subgingival plaque, saliva, and cardiac valve tissue were collected from 42 patients with heart valve disease. Molecular analysis of Streptococcus mutans, Prevotella intermedia, Porphyromonas gingivalis, and Treponema denticola was performed through real-time PCR. The micro-organism most frequently detected in heart valve samples was the S. mutans (89.3%), followed by P. intermedia (19.1%), P. gingivalis (4.2%), and T. denticola (2.1%). The mean decayed, missing, filled teeth (DMFT) was 26.4 ± 6.9 (mean ± SD), and according to the highest score of periodontal disease observed for each patient, periodontal pockets > 4 mm and dental calculus were detected in 43.4% and 34.7% of patients, respectively. In conclusion, oral bacteria, especially S. mutans, were found in the cardiac valve samples of patients with a high rate of caries and gingivitis/periodontitis. PMID:26632711

  12. Evolving hybrid approaches: the preservation of the 'neglected' pulmonary valve function in patients with congenital heart disease.

    Science.gov (United States)

    Vida, Vladimiro L; Bacha, Emile; Stellin, Giovanni

    2016-07-01

    The involvement of the hemodynamic expertise in the operating room led to the development of new strategies aimed to improve both early and long-term outcome of patients with congenital heart disease. During the last decade, with the aim of preserving the pulmonary valve function, we embarked on a new surgical approach, which combines surgical and interventional techniques, which are performed in the operating room. We believe that the preservation of the pulmonary valve function can be extended to any patients with classic tetralogy of Fallot and other selected patients with congenital pulmonary valve hypoplasia and dysfunction. PMID:26950198

  13. Computational Simulations of Flow Dynamics and Blood Damage Through a Bileaflet Mechanical Heart Valve Scaled to Pediatric Size and Flow

    OpenAIRE

    Yun, B. Min; McElhinney, Doff B.; Arjunon, Shiva; Mirabella, Lucia; Aidun, Cyrus K.; Yoganathan, Ajit P.

    2014-01-01

    Despite pressing needs, there are currently no FDA approved prosthetic valves available for use in the pediatric population. This study is performed for predictive assessment of blood damage in bileaflet mechanical heart valves (BMHVs) with pediatric sizing and flow conditions. A model of an adult-sized 23mm St. Jude Medical (SJM) Regent™ valve is selected for use in simulations, which is scaled in size for a 5-year old child and 6-month old infant. A previously validated lattice-Boltzmann me...

  14. Sleep and wake phase of heart beat dynamics by artificial insymmetrised patterns

    Science.gov (United States)

    Dudkowska, A.; Makowiec, D.

    2004-05-01

    In order to determine differences between healthy patients and patients with congestive heart failure we apply the artificial insymmetrised pattern (AIP) method. The AIP method by exploring a human eye ability to extract regularities and read symmetries in a dot pattern, serves a tool for qualitative discrimination of heart rate states.

  15. A Computational Tool for the Microstructure Optimization of a Polymeric Heart Valve Prosthesis.

    Science.gov (United States)

    Serrani, M; Brubert, J; Stasiak, J; De Gaetano, F; Zaffora, A; Costantino, M L; Moggridge, G D

    2016-06-01

    Styrene-based block copolymers are promising materials for the development of a polymeric heart valve prosthesis (PHV), and the mechanical properties of these polymers can be tuned via the manufacturing process, orienting the cylindrical domains to achieve material anisotropy. The aim of this work is the development of a computational tool for the optimization of the material microstructure in a new PHV intended for aortic valve replacement to enhance the mechanical performance of the device. An iterative procedure was implemented to orient the cylinders along the maximum principal stress direction of the leaflet. A numerical model of the leaflet was developed, and the polymer mechanical behavior was described by a hyperelastic anisotropic constitutive law. A custom routine was implemented to align the cylinders with the maximum principal stress direction in the leaflet for each iteration. The study was focused on valve closure, since during this phase the fibrous structure of the leaflets must bear the greatest load. The optimal microstructure obtained by our procedure is characterized by mainly circumferential orientation of the cylinders within the valve leaflet. An increase in the radial strain and a decrease in the circumferential strain due to the microstructure optimization were observed. Also, a decrease in the maximum value of the strain energy density was found in the case of optimized orientation; since the strain energy density is a widely used criterion to predict elastomer's lifetime, this result suggests a possible increase of the device durability if the polymer microstructure is optimized. The present method represents a valuable tool for the design of a new anisotropic PHV, allowing the investigation of different designs, materials, and loading conditions. PMID:27018454

  16. Transcatheter mitral valve repair with mitraclip for significant mitral regurgitation long after heart transplantion.

    Science.gov (United States)

    Ferraro, Paolo; Biondi-Zoccai, Giuseppe; Giordano, Arturo

    2016-07-01

    The role of transcatheter mitral valve repair with MitraClip implantation is becoming increasingly important for high-risk surgical patients with significant mitral regurgitation. Eligibility criteria for MitraClip are however rather strict, and the risk-benefit balance of this device in off-label settings remains unclear. Patients with prior heart transplantation may represent particularly challenging candidates for MitraClip, given their peculiar atrial anatomy. We hereby present the case of a 72-year-old gentleman with prior heart transplantation and significant mitral regurgitation who, after heart team consensus, was referred to us for MitraClip implantation. After careful planning, we were able to successfully implant two clips, achieving a significant improvement in the severity of the mitral regurgitation. Similarly favorable findings were confirmed at 3-month clinical and transthoracic/transesophageal echocardiographic follow-up. This clinical vignette highlights the key procedural milestones for successfully implanting MitraClip in patients with significant mitral regurgitation and prior heart transplantation. © 2015 Wiley Periodicals, Inc. PMID:26333048

  17. Animal Experiments of the Helical Flow Total Artificial Heart.

    Science.gov (United States)

    Abe, Yusuke; Isoyama, Takashi; Saito, Itsuro; Inoue, Yusuke; Ishii, Kohei; Sato, Masami; Hara, Shintaro; Yurimoto, Terumi; Li, Xinyang; Murakami, Haruka; Ariyoshi, Koki; Kawase, Yukino; Ono, Toshiya; Fukazawa, Kyoko; Ishihara, Kazuhiko

    2015-08-01

    Severe cardiac failure patients require a total artificial heart (TAH) to save life. To realize a TAH that can fit a body of small stature and has high performance, high durability, good anatomical fitting, good blood compatibility, and physiological control, we have been developing the helical flow TAH (HFTAH) with two helical flow pumps with hydrodynamic levitation impeller. Animal experiments of the HFTAH were conducted to perform in vivo studies. The HFTAH was implanted in 13 adult female goats weighing 45.0-64.0 kg. After surgery, neither anti-coagulant nor anti-platelet medication was given systemically. The HFTAH was usually driven with a quasi-pulsatile mode. The 1/R control or ΔP control was applied to control the circulation. The ΔP control is a new method using simplified equation of the 1/R control. The HFTAH could be implanted in all goats with good anatomical fitting. Two goats survived for a long time (100 and 68 days). Major causes of termination were device failure and surgical complications. In the device failure, trouble with hydrodynamic bearing was conspicuous. In the two long-term survived goats, experiments were terminated with bearing instability that was probably caused by the suction effect. In these goats, hemolysis occurred on postoperative day 88 and 44, which was considered to be relevant to the bearing trouble. Thrombus was found at the broken right bearing of the 100-day survived goat. However, antithrombogenicity of the pump is expected to be good unless bearing trouble occurs. In two long-term survived goats, the 1/R control or ΔP control worked appropriately to prevent the elevation of right atrial pressure. In both goats, hemodynamic parameters changed with the condition of the animals, liver and kidney functions remained almost normal except when recovering from surgery and during hemolysis, and total protein recovered 2 weeks after surgery. Although instability of the hydrodynamic bearing should be improved, performance of

  18. Total Artificial Heart Bridge to Transplantation for a Patient With Occult Intracardiac Malignancy: Case Report.

    Science.gov (United States)

    Reich, H; Czer, L; Bannykh, S; De Robertis, M; Wolin, E; Amersi, F; Moriguchi, J; Kobashigawa, J; Arabia, F

    2015-09-01

    Malignancy is the leading cause of long-term morbidity and mortality after heart and other solid organ transplantation; therefore, great emphasis is placed on pre- and post-transplantation cancer screening. Even with meticulous screening during evaluation for heart transplant candidacy, an occult cancer may not be apparent. Here, we share the case of a 51-year-old man with refractory heart failure who underwent total artificial heart implantation as a bridge to transplantation with the surprise finding of an isolated deposit of metastatic carcinoid tumor nested within a left ventricular papillary muscle in his explanted heart. The primary ileal carcinoid tumor was identified and resected completely. After remaining cancer-free for 14 months, he was listed for heart transplantation and was transplanted 2 months later. He is currently 3.5 months out from heart transplantation and doing well, without evidence of recurring malignancy. PMID:26361702

  19. Fluid-structure interaction of an aortic heart valve prosthesis driven by an animated anatomic left ventricle

    Science.gov (United States)

    Le, Trung Bao; Sotiropoulos, Fotis

    2013-07-01

    We develop a novel large-scale kinematic model for animating the left ventricle (LV) wall and use this model to drive the fluid-structure interaction (FSI) between the ensuing blood flow and a mechanical heart valve prosthesis implanted in the aortic position of an anatomic LV/aorta configuration. The kinematic model is of lumped type and employs a cell-based, FitzHugh-Nagumo framework to simulate the motion of the LV wall in response to an excitation wavefront propagating along the heart wall. The emerging large-scale LV wall motion exhibits complex contractile mechanisms that include contraction (twist) and expansion (untwist). The kinematic model is shown to yield global LV motion parameters that are well within the physiologic range throughout the cardiac cycle. The FSI between the leaflets of the mechanical heart valve and the blood flow driven by the dynamic LV wall motion and mitral inflow is simulated using the curvilinear immersed boundary (CURVIB) method (Ge and Sotiropoulos, 2007; Borazjani et al., 2008) [1,2] implemented in conjunction with a domain decomposition approach. The computed results show that the simulated flow patterns are in good qualitative agreement with in vivo observations. The simulations also reveal complex kinematics of the valve leaflets, thus, underscoring the need for patient-specific simulations of heart valve prosthesis and other cardiac devices.

  20. Three-dimensional color Doppler reconstruction of intracardiac blood flow in patients with different heart valve diseases.

    Science.gov (United States)

    De Simone, R; Glombitza, G; Vahl, C F; Meinzer, H P; Hagl, S

    2000-12-15

    An improved perception of the magnitude and dynamics of intracardiac flow disturbances has been made possible by the advent of 3-dimensional (3-D) color Doppler, a new diagnostic procedure developed at our institution. This study describes the new insights derived from 3-D reconstruction of color Doppler flow patterns in patients with different heart valve diseases. The color Doppler flow data from 153 multiplanar transesophageal or transthoracic echocardiographic examinations has been obtained from 133 patients with heart valve disease; 73 patients had mitral regurgitation, 15 had mitral stenosis, 18 had aortic regurgitation, 26 had aortic stenosis, and 21 patients had tricuspid regurgitation. Four patients had pulmonary regurgitation associated with mitral valve disease. The 3-D reconstructions of color Doppler flow signals were accomplished by means of the "Heidelberg Raytracing model," developed at our institution. The 3-D color Doppler reconstructions were obtained in all patients. The 3-D images revealed for the first time the complex spatial distribution of the blood flow abnormalities in the heart chambers caused by different heart valve diseases. New patterns of intracardiac blood flow disturbances were observed and classified. Three-dimensional color Doppler provides a unique noninvasive method that can be easily applied for studying intracardiac blood flow disturbances in clinical practice. PMID:11113410

  1. 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.)

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

    International Nuclear Information System (INIS)

    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.)

  3. Heart valve surgery in China: past and present%中国心脏瓣膜外科的发展与现状

    Institute of Scientific and Technical Information of China (English)

    张宝仁

    2001-01-01

    @@ Heart valve surgery in China dates back to 4 to 5 decades ago. In 1954, the first closed mitral commissurotomy was successfully performed in a patient with mitral stenosis. In 1960, with the advent of transventricular dilator and by the route of left ventricle, the efficacy of mitral commissurotomy was improved. The procedure was rapidly adopted by many centers in this country[1]. In 1958, the first open heart surgery using cardiopulmonary bypass was performed in China. This was an epoch-making event, which opened up a new era in the field of cardiac surgery in China. Thereafter, in cities like Beijing and Shanghai, direct repairs of mitral lesions under CPB were made with good results. In 1965, the development of the first totally home-made ball valve prosthesis and its successful application in mitral valve replacement was another landmark in the history of heart valve surgery in China. In 1976, aortic valve replacement with glutaraldehyde-preserved bovine pericardial valve prosthesis was carried out successfully. The next year, the first porcine aortic valve prosthesis was produced and introduced to clinical use, which greatly accelerated the progress of heart valve surgery in China. During the last 2 decades, heart valve surgery and its techniques have been widely applied throughout China.

  4. Detection of Heart Diseases by Mathematical Artificial Intelligence Algorithm Using Phonocardiogram Signals

    Directory of Open Access Journals (Sweden)

    D. Prakash

    2013-05-01

    Full Text Available An artificial intelligence (AI algorithm has been developed using Mathematical formula to diagnose heart disease from Phonocardiogram (PCG signals. Auscultation, the technique of listening to heart sounds with a stethoscope can be used as a primary detection technique for detecting heart disorders for the past years. But now the Phonocardiogram, the digital recording of heart sounds is becoming very popular technique as it is relatively inexpensive. Four amplitude parameters of the PCG signal are extracted by using filter technique and are used as input. PCG signals for three types of heart diseases such as Tachycardia, Bradycardia and Atrial fibrillation were used in this paper to test the accuracy. These disease types that affect the electrical system of heart are known as arrhythmias, cause the heart to beat very fast (Tachycardia or very slow (Bradycardia, or unexpectedly (Atrial fibrillation. After the signals are filtered and the parameters are extracted, the parameters are fed to the AI algorithm. Classifications of heart diseases are carried using the AI algorithm by comparing the extracted parameters. Here comparison is done using Min Max method. The developed mathematical artificial intelligence algorithm is implemented in MATLab using Simulink and the simulation results proved that the developed algorithm has been shown to be a powerful technique in detection of heart diseases using PCG signals.

  5. Role of nuclear imaging in the management of the first total artificial heart recipient

    International Nuclear Information System (INIS)

    On December 2, 1982, a permanent total artificial heart was implanted into the chest of a 61-year-old man with a progressive and irreversible cardiomyopathy. During the ensuing four-month hospitalization, a number of nuclear medicine procedures were obtained to assist in patient management. These procedures included gated cardiac radionuclide ventriculography, an I-123 iodoamphetamine scan for cerebral perfusion, and In-111 labeled leukocyte imaging. These radionuclide studies demonstrate the advantages of being able to monitor physiologic changes noninvasively and illustrate a potential role for nuclear cardiology in managing patients with a total artificial heart

  6. Minimally invasive thoracotomy approach for double valve replacement for valvular heart diseases

    Directory of Open Access Journals (Sweden)

    Ab Gani Ahangar

    2014-01-01

    Full Text Available Background: Double valve replacement (DVR is usually done through median sternotomy. However, right anterolateral thoracotomy is an alternative approach. Aim: The aim of this study was to analyze the results of right anterolateral thoracotomy for DVR. Patients and Methods: This was a prospective study conducted on during the period from January 2009 to January 2012. This study consists of 56 patients who had a concomitant mitral and aortic valve disease and were subjected to DVR. Patients were studied according to their age and sex, New York Heart Association (NYHA class, valve pathology, concomitant procedures, urgent/elective, length of incision, surgical exposure, mean bypass time, operating time, hospital stay, and cosmesis. Results: Majority of the patients were in 3 rd and 4 th decade (61%. Postoperative length of stay was 7-12 days, 70% of patients were discharged by the 7 th day. The average size of incision in males was 7.5 cm and in females the size of incision was 7.25 cm with a mean of 7.3 cm in both genders. Rheumatic heart disease was responsible for 89.28% of cardiac valvular lesions, degenerative disease in 7.14% and endocarditis in 3.5%. Postoperatively at 2 months, there was a statistically significant improvement in the NYHA class with 94% of the survivors in class I-II. There was a statistically significant difference in the outcome in patients having higher ejection fraction as compared to those who had low ejection fraction preoperatively. Thirty days mortality was 1.78%. Over the first 24 postoperative hours, only about 30% of patients were pain free, and this proportion increased to about 50% by day 2, 60% by day 3, 70% by day 4, 75% by day 5 and stabilized. Postoperative length of stay was 7-12 days, 70% of patients were discharged by the 7 th day. Conclusion: DVR via thoracotomy appears to be associated with faster recover, early discharge and reduced use of rehabilitation facilities that translate into a shorter

  7. Experimental validation of the fluid-structure interaction simulation of a bioprosthetic aortic heart valve.

    Science.gov (United States)

    Kemp, I; Dellimore, K; Rodriguez, R; Scheffer, C; Blaine, D; Weich, H; Doubell, A

    2013-09-01

    Experiments performed on a 19 mm diameter bioprosthetic valve were used to successfully validate the fluid-structure interaction (FSI) simulation of an aortic valve at 72 bpm. The FSI simulation was initialized via a novel approach utilizing a Doppler sonogram of the experimentally tested valve. Using this approach very close quantitative agreement (≤12.5%) between the numerical predictions and experimental values for several key valve performance parameters, including the peak systolic transvalvular pressure gradient, rapid valve opening time and rapid valve closing time, was obtained. The predicted valve leaflet kinematics during opening and closing were also in good agreement with the experimental measurements. PMID:23907849

  8. Experimental validation of the fluid–structure interaction simulation of a bioprosthetic aortic heart valve

    International Nuclear Information System (INIS)

    Experiments performed on a 19 mm diameter bioprosthetic valve were used to successfully validate the fluid–structure interaction (FSI) simulation of an aortic valve at 72 bpm. The FSI simulation was initialized via a novel approach utilizing a Doppler sonogram of the experimentally tested valve. Using this approach very close quantitative agreement (≤12.5 %) between the numerical predictions and experimental values for several key valve performance parameters, including the peak systolic transvalvular pressure gradient, rapid valve opening time and rapid valve closing time, was obtained. The predicted valve leaflet kinematics during opening and closing were also in good agreement with the experimental measurements.

  9. The operative diagnostics to adaptation heart to physical load on the base of artificial neuron networks

    OpenAIRE

    Timoshchenko E.V.

    2010-01-01

    In article are considered questions of the revealing the breach of the warmhearted rhythm beside athlete and athlete during physical load. The estimation of the condition heart was defined as of electrocardiographically of the examination. Mathematical model is designed for interpreting electrocardiogram data on base artificial neuron networks. It is created software, which allows to conduct the diagnostics of the heart diseases in the field of discovery different arrhythmias. Introduction re...

  10. Validation of four different risk stratification models in patients undergoing heart valve surgery in a single center in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-xiao; XU Jian-ping; GE Yi-peng; WEI Yu; YANG Yan; LIU Feng; SHI Yi

    2011-01-01

    Background Several risk stratification models have been developed for cardiac surgery. This study aimed to evaluate the accuracy of four existing risk stratification models, the Fuwai System for Cardiac Operative Risk Evaluation (FuwaiSCORE), the Society of Thoracic Surgeons 2008 cardiac surgery risk model for isolated valve surgery (the STS model), the European System for Cardiac Operative Risk Evaluation (EuroSCORE) and the initial Parsonnet's score (the Parsonnet model) in predicting prolonged intensive care unit (ICU) stay in Chinese patients undergoing heart valve surgery. Methods Data were collected retrospectively from records of 1333 consecutive patients who received heart valve surgery in a single center between November 2006 and December 2007. Prolonged ICU stay was defined as not less than 124 hours. Calibration was assessed using the Hosmer-Lemeshow (H-L) goodness of fit test. Discrimination was assessed using the receiver-operating-characteristic (ROC) curve area. Results The FuwaiSCORE showed good calibration and discrimination compared with other risk models. According to the H-L statistics, the value of the FuwaiSCORE was 12.82, P>0.1. The area under ROC curve of the FuwaiSCORE was 0.81 (95%C/0.78-0.84). Conclusions Our study suggests that the FuwaiSCORE is superior to the other three risk models in predicting prolonged length of ICU stay in Chinese patients with heart valve surgery. Having fewer variables, the system is much easier for bedside use than other systems.

  11. Considerations and Recommendations for the Introduction of Objective Performance Criteria for Transcatheter Aortic Heart Valve Device Approval.

    Science.gov (United States)

    Head, Stuart J; Mylotte, Darren; Mack, Michael J; Piazza, Nicolo; van Mieghem, Nicolas M; Leon, Martin B; Kappetein, A Pieter; Holmes, David R

    2016-05-24

    In the United States, new surgical heart valves can be approved on the basis of objective performance criteria (OPC). In contrast, the US Food and Drug Administration traditionally requires stricter criteria for transcatheter heart valve (THV) approval, including randomized, clinical trials. Recent US Food and Drug Administration approval of new-generation THVs based on single-arm studies has generated interest in alternative study approaches for THV device approval. This review evaluates whether THV device approval could follow a pathway analogous to that of surgical heart valves by incorporating OPC and provides several considerations and recommendations. Factors to be taken into account in the construction of OPC include the maturity of THV technology, variability in transcatheter aortic valve replacement practice, end points included as OPC, follow-up terms for specific OPC, patient populations to which these OPC apply, and (statistical) methods for OPC development. We recommend that approval of THV devices in the United States for low- and intermediate-risk patients or for new indications should provisionally rely on data from randomized, clinical trials. However, it is recommended that formal OPC be applied for approval of new-generation THVs for use in high- and extreme-risk patient populations. PMID:27217434

  12. ERDA artificial heart program workshop. Final report, September 1, 1975--August 31, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Kantrowitz, A.; Altieri, F.; Beall, A.

    1976-08-01

    The major conclusions of the ERDA Artificial Heart Program Workshop are that the concept of a biologically compatible mechanical device which can totally replace the heart is sound, that such a device is needed as an alternative to cardiac transplantation and that its development is a realistic goal. The major recommendation of the committee is that an ERDA program with primary orientation toward development of a total heart replacement should continue, with assured funding about 50 percent higher than at present, for a minimum of 3 additional years at which time another major review should take place. To achieve better management of the program it is recommended that the present contract effort be reorganized under one prime contractor with responsibility for development and demonstration of the ERDA artificial heart system. The formation of a joint artificial heart advisory committee to improve coordination between ERDA and NHLI is also recommended. The committee suggests future policies and directions which it believes will lead to more effective use of funds available for specific aspects of the program. These include the nuclear heart source, engine, blood pump, biomaterials and overall system reliability. Possible future goals for the program are also proposed.

  13. ERDA artificial heart program workshop. Final report, September 1, 1975--August 31, 1976

    International Nuclear Information System (INIS)

    The major conclusions of the ERDA Artificial Heart Program Workshop are that the concept of a biologically compatible mechanical device which can totally replace the heart is sound, that such a device is needed as an alternative to cardiac transplantation and that its development is a realistic goal. The major recommendation of the committee is that an ERDA program with primary orientation toward development of a total heart replacement should continue, with assured funding about 50 percent higher than at present, for a minimum of 3 additional years at which time another major review should take place. To achieve better management of the program it is recommended that the present contract effort be reorganized under one prime contractor with responsibility for development and demonstration of the ERDA artificial heart system. The formation of a joint artificial heart advisory committee to improve coordination between ERDA and NHLI is also recommended. The committee suggests future policies and directions which it believes will lead to more effective use of funds available for specific aspects of the program. These include the nuclear heart source, engine, blood pump, biomaterials and overall system reliability. Possible future goals for the program are also proposed

  14. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... in our practice, those being tissue valves and mechanical valves. Tissue valves, if I can demonstrate here, ... can expect. This is an example of a mechanical heart valve which is made out of pyrolitic ...

  15. The mediator complex subunit Med10 regulates heart valve formation in zebrafish by controlling Tbx2b-mediated Has2 expression and cardiac jelly formation.

    Science.gov (United States)

    Just, Steffen; Hirth, Sofia; Berger, Ina M; Fishman, Mark C; Rottbauer, Wolfgang

    2016-09-01

    In search for novel key regulators of cardiac valve formation, we isolated the zebrafish cardiac valve mutant ping pong (png). We find that an insertional promoter mutation within the zebrafish mediator complex subunit 10 (med10) gene is leading to impaired heart valve formation. Expression of the T-box transcription factor 2b (Tbx2b), known to be essential in cardiac valve development, is severely reduced in png mutant hearts. We demonstrate here that transient reconstitution of Tbx2b expression rescues AV canal development in png mutant zebrafish. By contrast, overexpression of Forkhead box N4 (Foxn4), a known upstream regulator of Tbx2b, is not capable to reconstitute tbx2b expression and heart valve formation in Med10-deficient png mutant hearts. Interestingly, hyaluronan synthase 2 (has2), a known downstream target of Tbx2 and producer of hyaluronan (HA) - a major ECM component of the cardiac jelly and critical for proper heart valve development - is completely absent in ping pong mutant hearts. We propose here a rather unique role of Med10 in orchestrating cardiac valve formation by mediating Foxn4 dependent tbx2b transcription, expression of Has2 and subsequently proper development of the cardiac jelly. PMID:27343557

  16. Cavitation phenomena in mechanical heart valves: studied by using a physical impinging rod system.

    Science.gov (United States)

    Lo, Chi-Wen; Chen, Sheng-Fu; Li, Chi-Pei; Lu, Po-Chien

    2010-10-01

    When studying mechanical heart valve cavitation, a physical model allows direct flow field and pressure measurements that are difficult to perform with actual valves, as well as separate testing of water hammer and squeeze flow effects. Movable rods of 5 and 10 mm diameter impinged same-sized stationary rods to simulate squeeze flow. A 24 mm piston within a tube simulated water hammer. Adding a 5 mm stationary rod within the tube generated both effects simultaneously. Charged-coupled device (CCD) laser displacement sensors, strobe lighting technique, laser Doppler velocimetry (LDV), particle image velocimetry (PIV) and high fidelity piezoelectric pressure transducers measured impact velocities, cavitation images, squeeze flow velocities, vortices, and pressure changes at impact, respectively. The movable rods created cavitation at critical impact velocities of 1.6 and 1.2 m/s; squeeze flow velocities were 2.8 and 4.64 m/s. The isolated water hammer created cavitation at 1.3 m/s piston speed. The combined piston and stationary rod created cavitation at an impact speed of 0.9 m/s and squeeze flow of 3.2 m/s. These results show squeeze flow alone caused cavitation, notably at lower impact velocity as contact area increased. Water hammer alone also caused cavitation with faster displacement. Both effects together were additive. The pressure change at the vortex center was only 150 mmHg, which cannot generate the magnitude of pressure drop required for cavitation bubble formation. Cavitation occurred at 3-5 m/s squeeze flow, significantly different from the 14 m/s derived by Bernoulli's equation; the temporal acceleration of unsteady flow requires further study. PMID:20490686

  17. Valvular heart disease: assessment of valve morphology and quantification using MR

    International Nuclear Information System (INIS)

    For clinical evaluation and decision-making in patients with valvular heart disease, the diagnostic armamentarium expands steadily. This evolution makes it difficult to choose the most appropriate approach for a specific valvular lesion. It may also reflect our uncertainty of what are the findings that best predict clinical outcome of patients, e. g. after surgery. Accordingly, for each type of valvular lesion, some pathophysiological considerations are stated in order to derive the most important measures that would allow optimal guidance of patients. Based on these considerations the value of an MR study is discussed for each valvular lesion. Newest advances in MR technology allow for highly accurate measurements of regurgitant volumes and hence, MR may be the method of choice for a quantitative evaluation of regurgitant valves. For assessment of stenosis severity, measurement of transvalvular pressure gradient is an appropriate measure and MR may not confer benefits over echocardiography, provided the ultrasound window is adequate (and stroke volume is in the normal range). With respect to surgical treatment, valvular morphology is of pivotal importance, particularly for the mitral valve, and echocardiography still appears to be the first line method. Little data relate lesion severity and/or morphology to clinical outcome. Conversely, the extent of cardiac adaptation to pressure- and/or volume-overload, i. e. ventricular remodeling, is a strong predictor of outcome, and is therefore most important for final judgement of the patient. For assessment of left and right ventricular remodeling, echocardiography typically provides all the necessary information. However, in special cases with discrepant findings, with inadequate ultrasound window, or in the preoperative work-up, MR may provide important information regarding cardiac adaptation to valvular lesion. (orig.)

  18. Testing of Safety-Critical Software Embedded in an Artificial Heart

    Science.gov (United States)

    Cha, Sungdeok; Jeong, Sehun; Yoo, Junbeom; Kim, Young-Gab

    Software is being used more frequently to control medical devices such as artificial heart or robotic surgery system. While much of software safety issues in such systems are similar to other safety-critical systems (e.g., nuclear power plants), domain-specific properties may warrant development of customized techniques to demonstrate fitness of the system on patients. In this paper, we report results of a preliminary analysis done on software controlling a Hybrid Ventricular Assist Device (H-VAD) developed by Korea Artificial Organ Centre (KAOC). It is a state-of-the-art artificial heart which completed animal testing phase. We performed software testing in in-vitro experiments and animal experiments. An abnormal behaviour, never detected during extensive in-vitro analysis and animal testing, was found.

  19. THE ROLE OF ORGAN LEVEL CONDITIONING ON THE PROMOTION OF ENGINEERED HEART VALVE TISSUE DEVELOPMENT IN-VITRO USING MESENCHYMAL STEM CELLS

    OpenAIRE

    Ramaswamy, Sharan; Gottlieb, Danielle; Engelmayr, George C.; Aikawa, Elena; Schmidt, David E.; Gaitan-Leon, Diana M.; Sales, Virna L.; Mayer, John E.; Sacks, Michael S.

    2009-01-01

    We have previously shown that combined flexure and flow (CFF) augment engineered heart valve tissue formation using bone marrow-derived mesenchymal stem cells (MSC) seeded on polyglycolic acid (PGA)/poly-L-lactic acid (PLLA) blend nonwoven fibrous scaffolds (Engelmayr, et al., Biomaterials 2006; vol. 27 pp. 6083–95). In the present study, we sought to determine if these phenomena were reproducible at the organ level in a functional tri-leaflet valve. Tissue engineered valve constructs (TEVC) ...

  20. Hemodynamic Flow Characterization of St. Jude Medical Bileaflet Mechanical and Bioprosthetic Heart Valve Prostheses in a Left Ventricular Model via Digital Particle Image Velocimetry

    OpenAIRE

    Pierrakos, Olga

    2002-01-01

    The performance of the heart after a valve replacement operation will greatly depend on the flow character downstream the mitral valve thus a better understanding of the flow character is essential. Most in vitro studies of the flow downstream of a MHV have been conducted with the valve in the aortic position. Researchers reported detailed measurements most of which were obtained by Laser Doppler Velocimetry (LDV) in rigid models of the aorta. Digital Particle Image Velocimetry (DPIV) has a...

  1. Dose-to-the-population exposure estimates for use of plutonium-238-powered artificial hearts

    Energy Technology Data Exchange (ETDEWEB)

    McKee, R.W.; Clark, L.L.; Cole, B.M.

    1976-09-01

    Estimates of dose to the population from /sup 238/Pu-powered artificial hearts were developed using a calculational model called REPRIEVE. This model develops the projected user population by incorporating assumptions regarding future heart disease death rates, the fraction dying who would be eligible candidates for artificial hearts, population projections, beginning implant rates, death rates after implant due to natural causes, and deaths caused by device failure. The user population was characterized by age, sex, household description, employment status and occupation. Census data on household descriptions and special surveys in selected cities provided the information necessary to describe persons exposed during both household and public activities. These surveys further defined distance and time of contact factors for these persons. Calculations using a dosemetry computer code defined the relationships between distance and dose. The validity of these calculations has been substantiated by experimental measurements.

  2. Dose-to-the-population exposure estimates for use of plutonium-238-powered artificial hearts

    International Nuclear Information System (INIS)

    Estimates of dose to the population from 238Pu-powered artificial hearts were developed using a calculational model called REPRIEVE. This model develops the projected user population by incorporating assumptions regarding future heart disease death rates, the fraction dying who would be eligible candidates for artificial hearts, population projections, beginning implant rates, death rates after implant due to natural causes, and deaths caused by device failure. The user population was characterized by age, sex, household description, employment status and occupation. Census data on household descriptions and special surveys in selected cities provided the information necessary to describe persons exposed during both household and public activities. These surveys further defined distance and time of contact factors for these persons. Calculations using a dosemetry computer code defined the relationships between distance and dose. The validity of these calculations has been substantiated by experimental measurements

  3. Effect of Ligustrazine hydrochloride on coagulation reaction and inflammation reaction in single valve replacement patients with rheumatic heart disease undergoing cardiopulmonary bypass

    Institute of Scientific and Technical Information of China (English)

    陈益君

    2014-01-01

    Objective To observe the protection effect of Ligustrazine Hydrochloride(LH)on coagulation reaction and inflammation reaction in single valve replacement patients with rheumatic heart disease undergoing cardiopulmonary bypass(CPB).Methods Totally 40 patients undergoing single valve replacement were recruited in the study and randomly assigned to the two groups,the treatment group

  4. Experimental investigation of the flow field past a bileaflet mechanical heart valve in pulsatile flow within an anatomical aorta model

    Science.gov (United States)

    Brown, Laura; Tavoularis, Stavros

    2011-11-01

    A bileaflet mechanical heart valve (BMHV) has been mounted at the inlet of an anatomical model of the human aorta, and placed within a mock circulation loop that simulates physiological flow conditions. The working fluid matches the refractive index of silicone, from which the aorta model and other parts of the test section are made, and the viscosity of blood. Flow characteristics past the BMHV are measured using stereoscopic and planar particle image velocimetry and laser Doppler velocimetry. In contrast to previous experiments, in which heart valves have been tested in simplified aortic geometries, this arrangement permits the study of the dependence of flow past the valve upon recirculation in the sinuses of Valsalva, the flow rate through the coronary arteries, and the aorta curvature. The effect of valve orientation will also be investigated with the objective to determine a hemodynamically optimal configuration with potential benefits to implantation procedures. The measured viscous shear stress distribution will be analyzed towards predicting the initiation of thrombosis in patients and identifying regions of stagnation, which could facilitate thrombus attachment.

  5. Heart transplantation as salvage therapy for progressive prosthetic valve endocarditis due to methicillin-resistant Staphylococcus epidermidis (MRSE)

    OpenAIRE

    Borde, J. P.; Sitaru, G.; Kopp, W. H.; Ruhparwar, A.; Ehlermann, P.; Lasitschka, F.; Dalpke, A.; Heininger, A

    2016-01-01

    Background Prosthetic valve endocarditis (PVE) has the highest in-hospital mortality among all cases of infective endocarditis (IE), it is estimated at about 40 %. Orthotopic heart transplantation (OHT) as a measure of last resort, may be considered in selected cases where repeated surgical procedures and conservative efforts have failed to eradicate persistent or recurrent IE. Only few clinical data are available regarding this rare indication for OHT, since active IE has traditionally been ...

  6. A novel iterative reconstruction algorithm allows reduced dose multidetector-row CT imaging of mechanical prosthetic heart valves

    OpenAIRE

    Habets, Jesse; Symersky, Petr; de Mol, Bas A. J. M.; Willem P Th M Mali; Leiner, Tim; Budde, Ricardo P.J.

    2011-01-01

    Multidetector-row CT is promising for prosthetic heart valve (PHV) assessment but retrospectively ECG-gated scanning has a considerable radiation dose. Recently introduced iterative reconstruction (IR) algorithms may enable radiation dose reduction with retained image quality. Furthermore, PHV image quality on the CT scan mainly depends on extent of PHV artifacts. IR may decrease streak artifacts. We compared image noise and artifact volumes in scans of mechanical PHVs reconstructed with conv...

  7. Auscultatory characteristics of normally functioning Lillehei-Kaster, Björk-Shiley, and St Jude heart valve prostheses.

    OpenAIRE

    Kupari, M.; Harjula, A; Mattila, S

    1986-01-01

    Auscultatory and echocardiographic and phonocardiographic studies were performed on 26 patients who had a total of 11 Lillehei-Kaster, 16 Björk-Shiley, and 18 St Jude heart valve prostheses functioning normally in the aortic or mitral positions or both. With all types and positions of prostheses a distinct closing sound was always detected. It was frequently heard in two parts which, according to echocardiographic and phonocardiographic studies, resulted from the onset and completion of the v...

  8. Computational simulations of flow dynamics and blood damage through a bileaflet mechanical heart valve scaled to pediatric size and flow.

    Science.gov (United States)

    Yun, B Min; McElhinney, Doff B; Arjunon, Shiva; Mirabella, Lucia; Aidun, Cyrus K; Yoganathan, Ajit P

    2014-09-22

    Despite pressing needs, there are currently no FDA approved prosthetic valves available for use in the pediatric population. This study is performed for predictive assessment of blood damage in bileaflet mechanical heart valves (BMHVs) with pediatric sizing and flow conditions. A model of an adult-sized 23 mm St. Jude Medical (SJM) Regent(™) valve is selected for use in simulations, which is scaled in size for a 5-year old child and 6-month old infant. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow with thousands of suspended platelets for cases of adult, child, and infant BMHV flows. Adult BMHV flows demonstrate more disorganized small-scale flow features, but pediatric flows are associated with higher fluid shear stresses. Platelet damage in the pediatric cases is higher than in adult flow, highlighting thrombus complication dangers of pediatric BMHV flows. This does not necessarily suggest clinically important differences in thromboembolic potential. Highly damaged platelets in pediatric flows are primarily found far downstream of the valve, as there is less flow recirculation in pediatric flows. In addition, damage levels are well below expected thresholds for platelet activation. The extent of differences here documented between the pediatric and adult cases is of concern, demanding particular attention when pediatric valves are designed and manufactured. However, the differences between the pediatric and adult cases are not such that development of pediatric sized valves is untenable. This study may push for eventual approval of prosthetic valves resized for the pediatric population. Further studies will be necessary to determine the validity and potential thrombotic and clinical implications of these findings. PMID:25011622

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

    Science.gov (United States)

    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

    2016-02-01

    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 low-dose CT (FDG-PET) and three-dimensional transoesophageal echocardiography (3D-TEE) may have additional value. This paper reviews the role of these novel imaging tools in the field of PHV obstruction and endocarditis.For acquired PHV obstruction, MDCT is of additional value in mechanical PHVs to differentiate pannus from thrombus as well as to dynamically study leaflet motion and opening/closing angles. For biological PHV obstruction, additional imaging is not beneficial as it does not change patient management. When performed on top of 2D-TTE/TEE, MDCT has additional value for the detection of both vegetations and pseudoaneurysms/abscesses in PHV endocarditis. FDG-PET has no complementary value for the detection of vegetations; however, it appears more sensitive in the early detection of pseudoaneurysms/abscesses. Furthermore, FDG-PET enables the detection of metastatic and primary extra-cardiac infections. Evidence for the additional value of 3D-TEE is scarce.As clinical implications are major, clinicians should have a low threshold to perform additional MDCT in acquired mechanical PHV obstruction. For suspected PHV endocarditis, both FDG-PET and MDCT have complementary value. PMID:26744343

  10. Improved Geometry of Decellularized Tissue Engineered Heart Valves to Prevent Leaflet Retraction.

    Science.gov (United States)

    Sanders, Bart; Loerakker, Sandra; Fioretta, Emanuela S; Bax, Dave J P; Driessen-Mol, Anita; Hoerstrup, Simon P; Baaijens, Frank P T

    2016-04-01

    Recent studies on decellularized tissue engineered heart valves (DTEHVs) showed rapid host cell repopulation and increased valvular insufficiency developing over time, associated with leaflet shortening. A possible explanation for this result was found using computational simulations, which revealed radial leaflet compression in the original valvular geometry when subjected to physiological pressure conditions. Therefore, an improved geometry was suggested to enable radial leaflet extension to counteract for host cell mediated retraction. In this study, we propose a solution to impose this new geometry by using a constraining bioreactor insert during culture. Human cell based DTEHVs (n = 5) were produced as such, resulting in an enlarged coaptation area and profound belly curvature. Extracellular matrix was homogeneously distributed, with circumferential collagen alignment in the coaptation region and global tissue anisotropy. Based on in vitro functionality experiments, these DTEHVs showed competent hydrodynamic functionality under physiological pulmonary conditions and were fatigue resistant, with stable functionality up to 16 weeks in vivo simulation. Based on implemented mechanical data, our computational models revealed a considerable decrease in radial tissue compression with the obtained geometrical adjustments. Therefore, these improved DTEHV are expected to be less prone to host cell mediated leaflet retraction and will remain competent after implantation. PMID:26183964

  11. Simulation of a pulsatile total artificial heart: Development of a partitioned Fluid Structure Interaction model

    Science.gov (United States)

    Sonntag, Simon J.; Kaufmann, Tim A. S.; Büsen, Martin R.; Laumen, Marco; Linde, Torsten; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2013-04-01

    Heart disease is one of the leading causes of death in the world. Due to a shortage in donor organs artificial hearts can be a bridge to transplantation or even serve as a destination therapy for patients with terminal heart insufficiency. A pusher plate driven pulsatile membrane pump, the Total Artificial Heart (TAH) ReinHeart, is currently under development at the Institute of Applied Medical Engineering of RWTH Aachen University.This paper presents the methodology of a fully coupled three-dimensional time-dependent Fluid Structure Interaction (FSI) simulation of the TAH using a commercial partitioned block-Gauss-Seidel coupling package. Partitioned coupling of the incompressible fluid with the slender flexible membrane as well as a high fluid/structure density ratio of about unity led inherently to a deterioration of the stability (‘artificial added mass instability’). The objective was to conduct a stable simulation with high accuracy of the pumping process. In order to achieve stability, a combined resistance and pressure outlet boundary condition as well as the interface artificial compressibility method was applied. An analysis of the contact algorithm and turbulence condition is presented. Independence tests are performed for the structural and the fluid mesh, the time step size and the number of pulse cycles. Because of the large deformation of the fluid domain, a variable mesh stiffness depending on certain mesh properties was specified for the fluid elements. Adaptive remeshing was avoided. Different approaches for the mesh stiffness function are compared with respect to convergence, preservation of mesh topology and mesh quality. The resulting mesh aspect ratios, mesh expansion factors and mesh orthogonalities are evaluated in detail. The membrane motion and flow distribution of the coupled simulations are compared with a top-view recording and stereo Particle Image Velocimetry (PIV) measurements, respectively, of the actual pump.

  12. THE STUDY OF CLINICAL APPLICATION OF ARTIFICIAL HEART%人工心脏临床应用研究

    Institute of Scientific and Technical Information of China (English)

    陈国涵; 刘中民; 卢蓉; 郭建华; 范慧敏; 刘泳; 李高平; 施巍巍; 李健

    2002-01-01

    Objective:To summarize practical experiences of clinical application of artificial heart and discuss its indications and prevention of complications. Methods: Before operation, all the four patients underwent regular treatment of internal medicine, and after its failure they were implanted with artificial hearts. Operations were performed under general anesthesia and external circulation at low temperature. Left ventricle assistant devices (LVAD) were used for three patients, and double ventricle assistant device (DVAP) for one. Two patients were embeded with Berlin artificial hearts (Melipot company). The other two were implanted with Medos artificial hearts ( Medos company). Results:All the patients had no infection and haemorrhage, while their cardiac functions were restored apparently. Three to five days after operation, patients could take off- bed activities. Two had been taken away their artificial hearts on 52th and 53th postoperative day, and arrhythmia disappeared. Half year follow- up revealed favorable results. One died,on 271st day,of bleeding from congenital cerebrovascular deformity. One died, on 10th postoperative day, of renal dysfunction and DIC. Conclusion: Artificial heart or Ventricle assistant devices (VAD) could be used as temporary substitute for heart transplantation, and used in emergent heart attacks in order to restore cardiac function.

  13. Prevalence of De Novo Aortic Valve Insufficiency in Patients After HeartWare VAD Implantation with an Intermittent Low-Speed Algorithm.

    Science.gov (United States)

    Saeed, Diyar; Westenfeld, Ralf; Maxhera, Bujar; Keymel, Stefanie; Sherif, Ahmed; Sadat, Najla; Petrov, GeorGI; Albert, Alexander; Lichtenberg, Artur

    2016-01-01

    De novo aortic valve insufficiency (AI) is a frequent occurrence in patients supported with left ventricular assist device (LVAD). The European version of the HeartWare LVAD has intermittent low-speed software (lavare cycle) to facilitate intermittent aortic valve opening. We examined aortic valve opening status and prevalence of AI in patients supported with HeartWare LVAD and activated lavare cycle. HeartWare LVAD patients were prospectively monitored using serial echocardiograms at different time points after the LVAD implantation. Inclusion criteria were patients with no > mild AI and/or no aortic valve surgery at the time of LVAD implantation and at least 60 days of support. Three of 37 patients had aortic valve surgery and were excluded from the analysis. A total of 34 patients with mean age of 57 ± 12 years met the inclusion criteria. After median support duration of 408 days (77-1250 days), eight patients had trace/mild AI (24%) and one patient developed moderate AI (3%). An average pump flow, speed, and mean arterial pressure of 4.4 ± 0.6 L/min, 2,585 ± 147 rpm, and 88 ± 11 mmHg were documented, respectively. Aortic valve opening was persistently seen in 22 patients (65%). Aortic valve opening is frequent, and the development of > mild AI seems to be rare in patients supported with HeartWare LVAD. PMID:27195744

  14. The operative diagnostics to adaptation heart to physical load on the base of artificial neuron networks

    Directory of Open Access Journals (Sweden)

    Timoshchenko E.V.

    2010-03-01

    Full Text Available In article are considered questions of the revealing the breach of the warmhearted rhythm beside athlete and athlete during physical load. The estimation of the condition heart was defined as of electrocardiographically of the examination. Mathematical model is designed for interpreting electrocardiogram data on base artificial neuron networks. It is created software, which allows to conduct the diagnostics of the heart diseases in the field of discovery different arrhythmias. Introduction result called on work can render the practical help at determination of the breaches of the warmhearted rhythm.

  15. Postoperative Migration of an Edwards-SAPIEN XT Mitral Valve-in-Valve Treated With Direct Vision Implantation During Beating-Heart Bypass.

    Science.gov (United States)

    Mick, Stephanie L; Roselli, Eric E; Kapadia, Samir; Tuzcu, E Murat; Krishnaswamy, Amar; Svensson, Lars G

    2016-03-01

    Transcatheter valve-in-valve mitral valve replacement provides treatment options to high-risk patients but is subject to its own complications. We present the migration of a transcatheter balloon-expandable Edwards-SAPIEN XT valve (Edwards Lifesciences, Irvine, CA) within a previously implanted surgical Carpentier-Edwards valve (Edwards Lifesciences) and our novel approach to its treatment. PMID:26897205

  16. Development of an Animal Experimental Model for a Bileaflet Mechanical Heart Valve Prosthesis

    OpenAIRE

    Choo, Suk Jung; Kim, Kun Il; Park, Nam Hee; Song, Jong Min; Choi, In Cheol; Shim, Jee Yeon; Lee, Sang Kwon; Kwon, Young Joo; Kim, Chang Nyung; Lee, Jae Won

    2004-01-01

    The objective of this study was to develop a pre-clinical large animal model for the in vivo hemodynamic testing of prosthetic valves in the aortic position without the need for cardiopulmonary bypass. Ten male pigs were used. A composite valved conduit was constructed in the operating room by implanting a prosthetic valve between two separate pieces of vascular conduits, which bypassed the ascending aorta to the descending aorta. Prior to applying a side-biting clamp to the ascending aorta f...

  17. Progress on the Design and Development of the Continuous-Flow Total Artificial Heart

    OpenAIRE

    Kobayashi, Mariko; Horvath, David J.; Mielke, Nicole; Shiose, Akira; Kuban, Barry; Goodin, Mark; Fukamachi, Kiyotaka; Golding, Leonard A.R.

    2012-01-01

    Cleveland Clinic’s continuous-flow total artificial heart has one motor and one rotating assembly supported by a hydrodynamic bearing. The right hydraulic output is self regulated by passive axial movement of the rotating assembly to balance itself with the left output. The purpose of this article is to present progress in four areas of development: the automatic speed control system, self-regulation to balance right/left inlet pressures and flows, hemolysis testing using calf blood, and coup...

  18. December 2014 HeartWeek issue of cardiology in the young: highlights of HeartWeek 2014: diseases of the cardiac valves from the foetus to the adult.

    Science.gov (United States)

    Jacobs, Jeffrey P

    2014-12-01

    This December Issue of Cardiology in the Young represents the 12th annual publication generated from the two meetings that compose "HeartWeek in Florida". "HeartWeek in Florida", the joint collaborative project sponsored by the Cardiac Center at the Children's Hospital of Philadelphia, Pennsylvania, together with Johns Hopkins All Children's Heart Institute of Saint Petersburg, Florida, averages over 1000 attendees every year and is now recognised as one of the major planks of continuing medical and nursing education for those working in the fields of diagnosis and treatment of cardiac disease in the foetus, neonate, infant, child, and adult. "HeartWeek in Florida" combines the International Symposium on Congenital Heart Disease, organised by All Children's Hospital and Johns Hopkins Medicine and entering its 15th year, with the Annual Postgraduate Course in Pediatric Cardiovascular Disease, organised by The Children's Hospital of Philadelphia and entering its 18th year. This December, 2014 Issue of Cardiology in the Young features highlights of Johns Hopkins All Children's Heart Institute's 14th Annual International Symposium on Congenital Heart Disease, which was held at the Renaissance Vinoy Resort & Golf Club, Saint Petersburg, Florida, from 15-18 February, 2014. This Symposium was co-sponsored by The American Association for Thoracic Surgery (AATS) and had as its special focus " Diseases of the Cardiac Valves from the Fetus to the Adult ". We acknowledge the tremendous contributions made to paediatric and congenital cardiac care by Duke Cameron and Joel Brenner, and therefore we dedicate this December, 2014 HeartWeek Issue of Cardiology in the Young to them. Duke Cameron is Professor of Surgery at Johns Hopkins University and Cardiac Surgeon-in-Charge at The Johns Hopkins Hospital. Joel Brenner is Professor of Pediatrics at Johns Hopkins University and Director of the Taussig Heart Center at Bloomberg Children's Center, The Johns Hopkins Hospital. Together

  19. A NUMERICAL ANALYSIS OF THE BLOOD FLOW AROUND THE BILEAFLET MECHANICAL HEART VALVES WITH DIFFERENT ROTATIONAL IMPLANTATION ANGLES

    Institute of Scientific and Technical Information of China (English)

    HONG Taehyup; KIM Chang Nyung

    2011-01-01

    The effects of implantation angles of Bileaflet Mechanical Heart Valves (BMHVs) on the blood flow and the leaflet motion are investigated in this paper.The physiological blood flow interacting with the moving leaflets ofa BMHV is simulated with a strongly coupled implicit Fluid-Structure Interaction (FSI) method based on the Arbitrary-Lagrangian-Eulerian (ALE) approach and the dynamic mesh method (remeshing) in Fluent.BMHVs are widely used to be implanted to replace the diseascd heart valves,but the patients would suffer from some complications such as hemolysis,platelet activation,tissue overgrowth and device failure.These complications are closely related to both the flow characteristics near the valves and the leaflet dynamics.The currentnumerical model is validated against a previous experimental study.The numerical results show that as the rotation angle of BMHV is increased the degree of asymmetry of the blood flow and the leaflet motion is increased,which may lead to an unbalanced force acting on the BMHVs.This study shows the applicability of the FSI model for the interaction between the blood flow and the leaflet motion in BMHVs.

  20. CFD simulation of a novel bileaflet mechanical heart valve prosthesis: an estimation of the Venturi passage formed by the leaflets.

    Science.gov (United States)

    Yokoyama, Y; Medart, D; Hormes, M; Schmitz, C; Hamilton, K; Kwant, P B; Takatani, S; Schmitz-Rode, T; Steinseifer, U

    2006-12-01

    The aim of this study was to validate the flow characteristics of the novel Helmholtz-Institute Aachen Bileaflet (HIA-BL) heart valve prosthesis. The curved leaflets of the HIA-BL valve form a Venturi passage between the leaflets at peak systole. By narrowing the cross section the flow accelerates and the static pressure at the central passage decreases according to the Venturi effect. The low-pressure zone between the leaflets is expected to stabilize the leaflets in fully open position at peak systole. To investigate the Venturi passage, the flow fields of two valve geometries were investigated by CFD (Computational Fluid Dynamics): one geometry exhibits curved leaflets resulting in a Venturi passage; the other geometry features straight leaflets. The flow profiles, pressure distribution and resulting torque of both passages were compared and investigated. Although flow profiles downstream of both valves were similar, the flow passages between the leaflets were different for the investigated leaflet geometries. The straight leaflet passage showed a large boundary layer separation zone near the leaflets and the lowest pressure at the leading edge of the leaflet. The Venturi passage showed a reduction of the boundary layer separation zones and the lowest pressure between the leaflets could be found in the narrowest flow cross section of the Venturi passage. Additionally, the resulting torque showed that the Venturi passage produced an opening momentum. The results demonstrate that the Venturi passage stabilizes the leaflets in open position at peak systole. PMID:17219353

  1. Collagen tissue treated with chitosan solutions in carbonic acid for improved biological prosthetic heart valves.

    Science.gov (United States)

    Gallyamov, Marat O; Chaschin, Ivan S; Khokhlova, Marina A; Grigorev, Timofey E; Bakuleva, Natalia P; Lyutova, Irina G; Kondratenko, Janna E; Badun, Gennadii A; Chernysheva, Maria G; Khokhlov, Alexei R

    2014-04-01

    Calcification of bovine pericardium dramatically shortens typical lifetimes of biological prosthetic heart valves and thus precludes their choice for younger patients. The aim of the present work is to demonstrate that the calcification is to be mitigated by means of treatment of bovine pericardium in solutions of chitosan in carbonic acid, i.e. water saturated with carbon dioxide at high pressure. This acidic aqueous fluid unusually combines antimicrobial properties with absolute biocompatibility as far as at normal pressure it decomposes spontaneously and completely into H2O and CO2. Yet, at high pressures it can protonate and dissolve chitosan materials with different degrees of acetylation (in the range of 16-33%, at least) without any further pretreatment. Even exposure of the bovine pericardium in pure carbonic acid solution without chitosan already favours certain reduction in calcification, somewhat improved mechanical properties, complete biocompatibility and evident antimicrobial activity of the treated collagen tissue. The reason may be due to high extraction ability of this peculiar compressed fluidic mixture. Moreover, exposure of the bovine pericardium in solutions of chitosan in carbonic acid introduces even better mechanical properties and highly pronounced antimicrobial activity of the modified collagen tissue against adherence and biofilm formation of relevant Gram-positive and Gram-negative strains. Yet, the most important achievement is the detected dramatic reduction in calcification for such modified collagen tissues in spite of the fact that the amount of the thus introduced chitosan is rather small (typically ca. 1wt.%), which has been reliably detected using original tritium labelling method. We believe that these improved properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurised solutions in carbonic acid. PMID:24582232

  2. Chest radiographic findings and complications of the temporary implantation of the Jarvik-7 artificial heart while patients await orthotopic heart transplantation

    International Nuclear Information System (INIS)

    At the University of Pittsburgh, the authors have had 15 patients in whom Jarvik-7 hearts were implanted as a temporary measure while the patients awaited suitable donors for cardiac transplantation. The paper presents a brief description of the Jarvik-7 artificial heart, factors affecting patient selection, and the radiographic appearance of a normally functioning Jarvik-7 heart, and reviews the chest radiographic complications seen in this patient group, along with eventual patient outcome

  3. Magnetic-Field Immunity Examination and Evaluation of Transcutaneous Energy-Transmission System for a Totally Implantable Artificial Heart

    OpenAIRE

    Takahiko Yamamoto; Kohji Koshiji

    2012-01-01

    Transcutaneous energy transmission (TET) is the most promising noninvasive method for supplying driving energy to a totally implantable artificial heart. Induction-heating (IH) cookers generate a magnetic flux, and if a cooker is operated near a transcutaneous transformer, the magnetic flux generated will link with its external and internal coils. This will affect the performance of the TET and the artificial heart system. In this paper, we present the design and development of a coil to be u...

  4. Reverse endoventricular artificial obturator in tricuspid valve position. Experimental feasibility research study

    Czech Academy of Sciences Publication Activity Database

    Sochman, J.; Peregrin, J.H.; Pavcnik, D.; Uchida, B.T.; Timmermans, H.A.; Sedmera, David; Benada, Oldřich; Kofroňová, Olga; Keller, F.S.; Rosch, J.

    2014-01-01

    Roč. 63, č. 2 (2014), s. 157-165. ISSN 0862-8408 Grant ostatní: Univerzita Karlova(CZ) P35/LF1/5 Institutional support: RVO:67985823 ; RVO:61388971 Keywords : tricuspid valve regurgitation * catheterization * myxoma-like principle * tricuspid annular plane systolic excursion (TAPSE) Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 1.293, year: 2014

  5. Artificial aortic valve dysfunction due to pannus and thrombus – different methods of cardiac surgical management

    Science.gov (United States)

    Marcinkiewicz, Anna; Kośmider, Anna; Walczak, Andrzej; Zwoliński, Radosław; Jaszewski, Ryszard

    2015-01-01

    Introduction Approximately 60 000 prosthetic valves are implanted annually in the USA. The risk of prosthesis dysfunction ranges from 0.1% to 4% per year. Prosthesis valve dysfunction is usually caused by a thrombus obstructing the prosthetic discs. However, 10% of prosthetic valves are dysfunctional due to pannus formation, and 12% of prostheses are damaged by both fibrinous and thrombotic components. The authors present two patients with dysfunctional aortic prostheses who were referred for cardiac surgery. Different surgical solutions were used in the treatment of each case. Case study 1 The first patient was a 71-year-old woman whose medical history included arterial hypertension, stable coronary artery disease, diabetes mellitus, chronic obstructive pulmonary disease (COPD), and hypercholesterolemia; she had previously undergone left-sided mastectomy and radiotherapy. The patient was admitted to the Cardiac Surgery Department due to aortic prosthesis dysfunction. Transthoracic echocardiography revealed complete obstruction of one disc and a severe reduction in the mobility of the second. The mean transvalvular gradient was very high. During the operation, pannus covering the discs’ surface was found. A biological aortic prosthesis was reimplanted without complications. Case study 2 The second patient was an 87-year-old woman with arterial hypertension, persistent atrial fibrillation, and COPD, whose past medical history included gastric ulcer disease and ischemic stroke. As in the case of the first patient, she was admitted due to valvular prosthesis dysfunction. Preoperative transthoracic echocardiography revealed an obstruction of the posterior prosthetic disc and significant aortic regurgitation. Transesophageal echocardiography and fluoroscopy confirmed the prosthetic dysfunction. During the operation, a thrombus growing around a minor pannus was found. The thrombus and pannus were removed, and normal functionality of the prosthetic valve was restored

  6. An improved artificial physical optimization algorithm for dynamic dispatch of generators with valve-point effects and wind power

    International Nuclear Information System (INIS)

    Highlights: • Dynamic load economic dispatch with wind power (DLEDW) model is established. • Markov chains combined with scenario analysis method are used to predict wind power. • Chance constrained technique is used to simulate the impacts of wind forecast error. • Improved artificial physical optimization algorithm is proposed to solve DLEDW. • Heuristic search strategies are applied to handle the constraints of DLEDW. - Abstract: Wind power, a kind of promising renewable energy resource, has recently been getting more attractive because of various environmental and economic considerations. But the penetration of wind power with its fluctuation nature has made the operation of power system more intractable. To coordinate the reliability and operation cost, this paper established a stochastic model of dynamic load economic dispatch with wind integration (DLEDW). In this model, constraints such as ramping up/down capacity, prohibited operating zone are considered and effects of valve-point are taken into account. Markov chains combined with scenario analysis method is used to generate predictive values of wind power and chance constrained programming (CCP) is applied to simulate the impacts of wind power fluctuation on system operation. An improved artificial physical optimization algorithm is presented to solve the DLEDW problem. Heuristic strategies based on the priority list and stochastic simulation techniques are proposed to handle the constraints. In addition, a local chaotic mutation strategy is applied to overcome the disadvantage of premature convergence of artificial physical optimization algorithm. Two test systems with and without wind power integration are used to verify the feasibility and effectiveness of the proposed method and the results are compared with those of gravitational search algorithm, particle swarm optimization and standard artificial physical optimization. The simulation results demonstrate that the proposed method has a

  7. 国产人工机械瓣膜的历史与研究进展%History and Research Advance of China-made Mechanical Heart Valves

    Institute of Scientific and Technical Information of China (English)

    祁亮

    2013-01-01

    人工心脏瓣膜的应用至今已有50多年的历史,其中机械瓣膜在瓣膜病治疗中有着显著的临床疗效.回顾人工机械瓣膜的研究历史,大至经历了从第一代笼球瓣、笼碟瓣到第二代单叶侧倾碟瓣,再到第三代双叶机械瓣的发展过程.1960年国外首次应用笼球式机械瓣行心瓣膜置换术,我国在1963年也研制出了国产笼球瓣并应用于临床;1969年国外研制出第二代单叶侧倾碟瓣,国内于1978年研制出国产单叶侧倾碟瓣并广泛应用,取得了良好的临床疗效.从1980年双叶机械瓣问世至今,双叶瓣以优异的性能淘汰了以上两种瓣膜,成为当今的主流产品,而目前国内对双叶瓣的研发相对滞后,国内人工心脏瓣膜的市场也几乎被国外双叶瓣所垄断.因此,理想的人工心脏瓣膜有待国人继续研究开发.%Clinical application history of prosthetic heart valves has been over five decades, and mechanical heart valves have satisfactory clinical outcomes for surgical treatment of valvular heart disease. The development history of mechanical heart valves experienced from the first generation of ball valves and caged disc valves to the second generation of single tilting disc valve, and to the third generation of bileaflet valves. In 1960, ball valve was first used for heart valve replacement in abroad. In 1963, China-made ball valve was also produced and used in clinical practice. In 1969, the second generation of single tilting disc valve was developed in abroad. In 1978, China-made single tilting disc valve was produced and widely used in clinical practice with satisfactory clinical outcomes. Since 1980 when it was first produced, bileaflet valve has taken the place of above 2 types of valves for its excellent performance, and become the mainstream product all over the world. Currently, the development of China-made bileaflet valves has lagged behind, and domestic mechanical heart valve market has almost been

  8. Collagen tissue treated with chitosan solutions in carbonic acid for improved biological prosthetic heart valves

    Energy Technology Data Exchange (ETDEWEB)

    Gallyamov, Marat O., E-mail: glm@spm.phys.msu.ru [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Chaschin, Ivan S. [Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Khokhlova, Marina A. [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Grigorev, Timofey E. [Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation); Bakuleva, Natalia P.; Lyutova, Irina G.; Kondratenko, Janna E. [Bakulev Scientific Center for Cardiovascular Surgery of the Russian Academy of Medical Sciences, Roublyevskoe Sh. 135, Moscow 121552 (Russian Federation); Badun, Gennadii A.; Chernysheva, Maria G. [Radiochemistry Division, Faculty of Chemistry, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Khokhlov, Alexei R. [Faculty of Physics, Lomonosov Moscow State University, Leninskie gory 1–2, Moscow 119991 (Russian Federation); Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova 28, Moscow 119991 (Russian Federation)

    2014-04-01

    Calcification of bovine pericardium dramatically shortens typical lifetimes of biological prosthetic heart valves and thus precludes their choice for younger patients. The aim of the present work is to demonstrate that the calcification is to be mitigated by means of treatment of bovine pericardium in solutions of chitosan in carbonic acid, i.e. water saturated with carbon dioxide at high pressure. This acidic aqueous fluid unusually combines antimicrobial properties with absolute biocompatibility as far as at normal pressure it decomposes spontaneously and completely into H{sub 2}O and CO{sub 2}. Yet, at high pressures it can protonate and dissolve chitosan materials with different degrees of acetylation (in the range of 16–33%, at least) without any further pretreatment. Even exposure of the bovine pericardium in pure carbonic acid solution without chitosan already favours certain reduction in calcification, somewhat improved mechanical properties, complete biocompatibility and evident antimicrobial activity of the treated collagen tissue. The reason may be due to high extraction ability of this peculiar compressed fluidic mixture. Moreover, exposure of the bovine pericardium in solutions of chitosan in carbonic acid introduces even better mechanical properties and highly pronounced antimicrobial activity of the modified collagen tissue against adherence and biofilm formation of relevant Gram-positive and Gram-negative strains. Yet, the most important achievement is the detected dramatic reduction in calcification for such modified collagen tissues in spite of the fact that the amount of the thus introduced chitosan is rather small (typically ca. 1 wt.%), which has been reliably detected using original tritium labelling method. We believe that these improved properties are achieved due to particularly deep and uniform impregnation of the collagen matrix with chitosan from its pressurised solutions in carbonic acid. - Highlights: • Treatment of GA

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

    Directory of Open Access Journals (Sweden)

    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

  10. Micro Particle Image Velocimetry Measurements of Steady Diastolic Leakage Flow in the Hinge of a St. Jude Medical® Regent™ Mechanical Heart Valve

    OpenAIRE

    Jun, Brian H.; Saikrishnan, Neelakantan; Yoganathan, Ajit P.

    2013-01-01

    A number of clinical, in vitro and computational studies have shown the potential for thromboembolic complications in bileaflet mechanical heart valves (BMHV), primarily due to the complex and unsteady flows in the valve hinges. These studies have focused on quantitative and qualitative parameters such as velocity magnitude, turbulent shear stresses, vortex formation and platelet activation to identify potential for blood damage. However, experimental characterization of the whole flow fields...

  11. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... opens freely when the heart contracts. On the right, we see a picture of the aortic valve ... the aortic valve because the probe is sitting right behind the aortic valve. Lots of patients on ...

  12. Blood damage through a bileaflet mechanical heart valve: a quantitative computational study using a multiscale suspension flow solver.

    Science.gov (United States)

    Min Yun, B; Aidun, Cyrus K; Yoganathan, Ajit P

    2014-10-01

    Bileaflet mechanical heart valves (BMHVs) are among the most popular prostheses to replace defective native valves. However, complex flow phenomena caused by the prosthesis are thought to induce serious thromboembolic complications. This study aims at employing a novel multiscale numerical method that models realistic sized suspended platelets for assessing blood damage potential in flow through BMHVs. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow through a 23 mm St. Jude Medical (SJM) Regent™ valve in the aortic position at very high spatiotemporal resolution with the presence of thousands of suspended platelets. Platelet damage is modeled for both the systolic and diastolic phases of the cardiac cycle. No platelets exceed activation thresholds for any of the simulations. Platelet damage is determined to be particularly high for suspended elements trapped in recirculation zones, which suggests a shift of focus in blood damage studies away from instantaneous flow fields and toward high flow mixing regions. In the diastolic phase, leakage flow through the b-datum gap is shown to cause highest damage to platelets. This multiscale numerical method may be used as a generic solver for evaluating blood damage in other cardiovascular flows and devices. PMID:25070372

  13. Transcutaneous Optical Information Transmission System for a Totally Implantable Artificial Heart

    Science.gov (United States)

    Yamamoto, Takahiko; Koshiji, Kohji

    A transcutaneous optical information transmission system (TOITS) offers the most promising method for noninvasively transmitting the information to control a total artificial heart (TAH). We had used light-emitting diode (LED) and photo diode (PD) with different wavelengths for full-duplex bidirectional communication in the TOITS. In this study, reduction of optical crosstalk in full-duplex bidirectional communication was investigated by using a combination of two orthogonal polarizers with the same wavelength. As a result, we confirmed that optical crosstalk could be prevented for communication through a cow's skin (3.5 mm thick) and that the signal waveform could be transmitted satisfactorily.

  14. Aortic Valve Disease

    Science.gov (United States)

    ... valve opens when the left ventricle squeezes to pump out blood, and closes in between heart beats to keep ... the left ventricle has to work harder to pump blood out through the valve. To do this extra ...

  15. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... of that slide, that demonstrates that patients with New York Heart Association class heart failure 1 and ... right down the aortic valve and that's the new aortic valve that Dr. Streitman's placed. And you ...

  16. Mitral Valve Perforation in Libman-Sacks Endocarditis: A Heart-Wrenching Case of Lupus.

    Science.gov (United States)

    Aby, Elizabeth S; Rosol, Zachary; Simegn, Mengistu A

    2016-08-01

    Libman-Sacks (LS) endocarditis is one of the most common cardiac manifestations of systemic lupus erythematosus. Rarely, however, it can lead to serious complications, including severe valvular regurgitation or superimposed bacterial endocarditis. We describe the initial diagnostic challenges, clinical course, imaging studies and histopathological findings of a patient who presented with life-threatening lupus complicated by hemoptysis and respiratory failure secondary to a rare complication of LS endocarditis, acute mitral valve perforation. We review the current literature on valve perforation in the setting of LS endocarditis. In conclusion, although the disease is often asymptomatic and hemodynamically insignificant, it can result in serious and potentially fatal complications secondary to valve perforation, which may demand emergency surgical management. PMID:26976291

  17. An evaluation of the effects of long term cryopreservation, cause of death, and time between death and donation on heart valve leaflet viability

    International Nuclear Information System (INIS)

    The protocol for cryopreservation of allograft heart valves at the Donor Tissue Bank of Victoria was based on validation studies on the viability of the heart valve leaflets at the time of processing. The heart block is removed within 24 hours of death and the aor-tic and pulmonary valves trimmed immediately following retrieval. Following this processing, the valves are incubated in antibiotics at 30 degree C for 6 to 8 hours before being frozen in 10% DMSO at a controlled rate. A sample of tricuspid valve leaflet is placed in Krebs solution at the time of trimfning and is used for viability studies. Leaflet viability studies have been perfon-ned on all heart valves retrieved from 1993 to the present day at the Donor Tissue Bank of Victoria. Viability involves a qualitative assessment of the cellular outgrowth by leaflet fibroblasts, this assessment ranging from '-' for no outgrowth to '++++' for maximum outgrowth. Surgeons do not request valves with any particular viability and will use them whether they are viable or not. This evaluation was to determine the effects of long-term cryopreservation, cause of death, and also time lapse of heart removal following death on the viability of the retrieved leaflets. The aim of investigating the effects of long-term cryopreservation was to determine whether there was any correlation between initial viability and viability following storage for several months to several years. It was also decided to investigate whether there was any correlation between time length between death and heart retrieval and the viability. It was also thought that the cause of death may have had an effect on the viability, for example, did death by carbon monoxide poisoning have an effect on the viability of heart valve cells. Heart valves, which had been cryopreserved but could not be transplanted for various reasons were used to study the effects of cryopreservation in this study. These were thawed according to protocol and a sample of the valve

  18. Novel heart valve prosthesis with self-endothelialization potential made of modified polyhedral oligomeric silsesquioxane-nanocomposite material.

    Science.gov (United States)

    Ghanbari, Hossein; Radenkovic, Dina; Marashi, Sayed Mahdi; Parsno, Shirin; Roohpour, Nima; Burriesci, Gaetano; Seifalian, Alexander M

    2016-06-01

    In the cardiovascular system, the endothelial layer provides a natural antithrombogenic surface on the inner portion of the heart and associated vessels. For a synthetic material therefore, the ability to attract and retain endothelial or endothelial progenitor cells (EPCs), ultimately creating a single endothelial layer on its surface, is of prime importance. The authors have developed a nanocomposite polymer, based on a combination of polyhedral oligomeric silsesquioxane nanoparticles and polycarbonate urea urethane (POSS-PCU), which is biocompatible and has been used in human for the world's first synthetic trachea, tear duct, and bypass graft. In this study, the authors modified the surface of this casted nanocomposite by grafting fibronectin derived bioactive peptides [glycine-arginine-glycine-aspartic acid-glycine (GRGDG) and lauric acid conjugated GRGDG (GRGDG-LA)] to enhance the endothelialization for using heart valves leaflets from circulating EPCs. Human peripheral blood mononuclear cells were separated using Ficoll-Paque centrifugation, with harvested EPCs purified using CD34 microbead labeling and magnetic-activated cell sorting. Cells were seeded onto 96 well plates coated with POSS-PCU, GRGDG/GRGDG-LA modified POSS-PCU and PCU polymers, for a period of 21 days. Cells were studied under light, confocal, and scanning electron microscope (SEM). Fluorescence-activated cell sorting was used to analyze cell surface markers. Cell attachment and proliferation was observed in all POSS-PCU samples, significantly higher than the activity seen within the control PCU polymers (p PCU. The cells expressed increasing levels of mature endothelial cell markers over time with a concurrent reduction in hematopoietic stem cell marker expression. SEM showed a mixed population of morphologically differentiated endothelial cells and EPCs. These results support the use of heart valve made with the POSS-PCU polymer and demonstrate that suitable chemical modification of this

  19. Estimation of turbulent charakteristics of pulsatile flow behind artificial heart valves

    Czech Academy of Sciences Publication Activity Database

    Kořenář, Josef; Klimeš, František

    Praha : ÚT AVČR, 1997 - (Musil, J.; Maršík, F.), s. 38-46 ISBN 80-85918-30-7. [Workshop '97. Biomechanical modelling and numerical simulation . Praha (CZ), 25.09.1997-26.09.1997] R&D Projects: GA ČR GA101/96/1051

  20. Triple Björk-Shiley valve: More than 30 years of asymptomatic functioning: To the memory of late academic Prof. Isidor Papo and the 45th anniversary of the first valve implantation in Yugoslavia

    OpenAIRE

    Krotin Mirjana; Milenković-Krotin Jelisaveta; Zdravković Marija

    2010-01-01

    Introduction. The Björk-Shiley Delrin (BSD) tilting disc heart valve was first clinically used in 1969. A triple BSD valve replacement has not been quite common, because of high postoperative risk and complications, but there have been several cases with different postoperative course. The first implantation of artificial valve in Yugoslavia was done by Prof. Isidor Papo, in 1965. Case report. We presented patient with more than 30 years of successful triple (aortic, mitral and tricuspid) BSD...

  1. In vitro investigation of biological and technical prosthetic heart valves in MRI: evaluation of possible deflection and heating of the implants

    International Nuclear Information System (INIS)

    Purpose: In vitro evaluation of possible deflection and heating of present-day prosthetic heart valves, 12 technical and 5 biological, were investigated using a 1.5 Tesla Siemens Vision system. Deflection was measured at the edge of a 1.5 Tesla superconducting magnet. Each valve was then submerged in a vial of a 1/1 electrolyte solution and temperature was measured before and after imaging with a turbo-spin-echo sequence (TR 5200 ms, TE 138 ms, Flip angle 180 C, acquisition time 10.5 minutes, length of echo train 29). MR imaging was performed with phase encoding parallel and perpendicular to the plane of the valves. Results: None of the investigated prosthetic heart valves was deflected. The maximal observed temperature rise was 0.5 C. During MR investigation of the prostheses, artifacts caused by metallic parts were less evident using a spin-echo sequence than a gradient-echo sequence. Conclusions: Patients with the tested present-day prosthetic heart valves can be safely imaged by MRI. (orig.)

  2. Artificial heart system thermal converter and blood pump component research and development

    International Nuclear Information System (INIS)

    A bench model version of a nuclear-powered artificial heart system to be used as a replacement for the natural heart was constructed and tested as a part of a broader U. S. ERDA program. The objective of the broader program has been to develop a prototype of a fully implantable nuclear-powered total artificial heart system powered by the thermal energy of plutonium-238 and having minimum weight and volume and a minimum life of ten years. As a forward step in this broader program, component research and development has been carried out directed towards a fully implantable and advanced version of the bench model (IVBM). Some of the results of the component research and development effort on a Stirling engine, blood pump drive mechanisms, and coupling mechanisms are presented. The Stirling-mechanical system under development is shown. There are three major subassemblies: the thermal converter, the coupling mechanism, and the blood pump drive mechanism. The thermal converter uses a Stirling cycle to convert the heat of the plutonium-238 fueled heat source to a rotary shaft power output. The coupling mechanism changes the orientation of the output shaft by 90 degrees and transmits the pumping power by wire-wound core flexible shafting to the pumping mechanism. The coupling mechanism also provides routing of the coolant lines which carry the cycle waste heat from the thermal converter to the blood pump. The change in orientation of the thermal converter output shaft is for convenience in implanting in a calf. This orientation of thermal converter to blood pump seemed to give the best overall system fit in a calf based on fit trials with wooden models in a calf cadaver

  3. Are the Current Doppler Echocardiography Criteria Able to Discriminate Mitral Bileaflet Mechanical Heart Valve Malfunction? An In Vitro Study.

    Science.gov (United States)

    Evin, Morgane; Guivier-Curien, Carine; Pibarot, Philippe; Kadem, Lyes; Rieu, Régis

    2016-05-01

    Malfunction of bileaflet mechanical heart valves in the mitral position could either be due to patient-prosthesis mismatch (PPM) or leaflet obstruction. The aim of this article is to investigate the validity of current echocardiographic criteria used for diagnosis of mitral prosthesis malfunction, namely maximum velocity, mean transvalvular pressure gradient, effective orifice area, and Doppler velocity index. In vitro testing was performed on a double activation left heart duplicator. Both PPM and leaflet obstruction were investigated on a St. Jude Medical Master. PPM was studied by varying the St. Jude prosthesis size (21, 25, and 29 mm) and stroke volume (70 and 90 mL). Prosthesis leaflet obstruction was studied by partially or totally blocking the movement of one valve leaflet. Mitral flow conditions were altered in terms of E/A ratios (0.5, 1.0, and 1.5) to simulate physiologic panel of diastolic function. Maximum velocity, effective orifice area, and Doppler velocity index are shown to be insufficient to distinguish normal from malfunctioning St. Jude prostheses. Doppler velocity index and effective orifice area were 1.3 ± 0.49 and 1.83 ± 0.43 cm(2) for testing conditions with no malfunction below the 2.2 and 2 cm(2) thresholds (1.19 cm(2) for severe PPM and 1.23 cm(2) for fully blocked leaflet). The mean pressure gradient reached 5 mm Hg thresholds for several conditions of severe PPM only (6.9 mm Hg and mean maximum velocity value: 183.4 cm/s) whereas such value was never attained in the case of leaflet obstruction. In the case of leaflet obstruction, the maximum velocity averaged over the nine pulsed-wave Doppler locations increased by 38% for partial leaflet obstruction and 75% for a fully blocked leaflet when compared with normal conditions. Current echocardiographic criteria might be suboptimal for the detection of bileaflet mechanical heart valve malfunction. Further developments and investigations are required in order

  4. A sheep survived for 48 days with the biventricular bypass type total artificial heart.

    Directory of Open Access Journals (Sweden)

    Senoo,Yoshimasa

    1991-08-01

    Full Text Available A biventricular bypass type total artificial heart (BVB-TAH utilizing two pusher-plate pumps was developed and implanted in a sheep for 48 days with excellent results. A Hall effect sensor was utilized to operate each pump independently with a full stroke at variable rates (VR. With this system, the animal's hemodynamics was kept physiologically, and all metabolic parameters except hemoglobin and hematocrit returned to normal three weeks after implantation. However, signs of infection appeared on the forty-second day, and consequently the animal fell into a state of shock. Even at that time the BVB-TAH maintained circulation by increasing pumping rate automatically. On the forty-eighth day, the animal could not stand and suffered from anuria; the experiment was then terminated after 1,140 h pumping. At autopsy, there was an enlarged heart with an atrophic change, 1,900 ml of pleural effusion, and 3,100ml of ascites fluid. Blood culture taken on the forty-seventh day yielded Acinetobacter calcoaceticus. The BVB-TAH operated in an independent VR mode maintained entire circulation, and has a capability of substituting the native heart function in any situation.

  5. Changes in heart valve structure and function in patients treated with dopamine agonists for prolactinomas, a 2-year follow-up study.

    NARCIS (Netherlands)

    Delgado, V.; Biermasz, N.R.; Thiel, S.W. van; Ewe, S.H.; Marsan, N.A.; Holman, E.R.; Feelders, R.A.; Smit, J.W.A.; Bax, J.J.; Pereira, A.M.

    2012-01-01

    OBJECTIVE: The use of ergot-derived dopamine agonists (DA) to treat patients with prolactinomas has not been associated with an increased risk of significant heart valve dysfunction. Accordingly, the present study evaluated whether the long-term use of DA for hyperprolactinaemia may be associated wi

  6. The Progress of Tissue Engineering Heart Valve%组织工程心脏瓣膜构建现状与发展

    Institute of Scientific and Technical Information of China (English)

    赵东锷; 刘维永

    2001-01-01

    The currently used heart valve prosthesis are still far from the ideal one in anticoagulation and longevity. The construction of tissue engineering heart valve leaflets are carried out recently. This article reviews the progress of tissue engineering heart valve leaflets in implanting materials, seeded cells, animal experiment and basic research. It also discusses the benefits and feasibility of tissue engineering heart valve leaflets.%为了克服目前临床应用的人工心脏瓣膜在抗凝和衰坏方面的缺点,随着组织工程学的发展,构建组织工程心脏瓣膜的研究已取得初步进展。综述近年来组织工程心脏瓣膜在种植材料、种子细胞、动物实验和基础研究方面取得的进展,并探讨组织工程心脏瓣膜的优越性和可行性。

  7. Human micro-vascular endothelial cell seeding on Cr-DLC thin films for mechanical heart valve applications

    Energy Technology Data Exchange (ETDEWEB)

    Ali, N. [Centre for Mechanical Technology and Automation, University of Aveiro (Portugal)]. E-mail: n.ali@mec.ua.pt; Kousar, Y. [Centre for Mechanical Technology and Automation, University of Aveiro (Portugal); Okpalugo, T.I. [Northern Ireland Bio-Engineering Centre, NIBEC, University of Ulster (United Kingdom); Singh, V. [Center for Advanced Microstructures and Devices, Louisiana State University, Baton Rouge, LA 70806 (United States); Pease, M. [Center for Advanced Microstructures and Devices, Louisiana State University, Baton Rouge, LA 70806 (United States); Ogwu, A.A. [Thin Film Centre, University of Paisley, Scotland (United Kingdom); Gracio, J. [Centre for Mechanical Technology and Automation, University of Aveiro (Portugal); Titus, E. [Centre for Mechanical Technology and Automation, University of Aveiro (Portugal); Meletis, E.I. [Materials Science and Engineering, The University of Texas at Arlington, TX (United States); Jackson, M.J. [Department of Mechanical Engineering, University of Purdue (United States)

    2006-09-25

    In this investigation, chromium modified diamond-like-carbon (Cr-DLC) films were studied for potential applications in mechanical heart valves. Three Cr- DLC samples were prepared using a magnetron sputtering technique employing an intensified plasma assisted processing (IPAP) system. The three samples consisted of the following Cr content: 1 at.%, 5 at.% and 10 at.%. The biological response of human micro-vascular endothelial cells (HMV-EC) seeded on Cr-DLC films was evaluated in terms of initial cell attachment and growth. The Cr-DLC films were characterized using Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), secondary ion mass spectroscopy (SIMS) and by the contact angle technique. Endothelial cell adhesion and growth was found to be affected by changing the Cr content of Cr-DLC films.

  8. Human micro-vascular endothelial cell seeding on Cr-DLC thin films for mechanical heart valve applications

    International Nuclear Information System (INIS)

    In this investigation, chromium modified diamond-like-carbon (Cr-DLC) films were studied for potential applications in mechanical heart valves. Three Cr- DLC samples were prepared using a magnetron sputtering technique employing an intensified plasma assisted processing (IPAP) system. The three samples consisted of the following Cr content: 1 at.%, 5 at.% and 10 at.%. The biological response of human micro-vascular endothelial cells (HMV-EC) seeded on Cr-DLC films was evaluated in terms of initial cell attachment and growth. The Cr-DLC films were characterized using Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), secondary ion mass spectroscopy (SIMS) and by the contact angle technique. Endothelial cell adhesion and growth was found to be affected by changing the Cr content of Cr-DLC films

  9. Evaluation of a new Implicit Coupling Algorithm for the Partitioned Fluid-Structure Interaction Simulation of Bileaflet Mechanical Heart Valves

    International Nuclear Information System (INIS)

    We present a newly developed Fluid-Structure Interaction coupling algorithm to simulate Bileaflet Mechanical Heart Valves dynamics in a partitioned way. The coupling iterations between the flow solver and the leaflet motion solver are accelerated by using the Jacobian with the derivatives of the pressure and viscous moments acting on the leaflets with respect to the leaflet acceleration. This Jacobian is used in the leaflet motion solver when new positions of the leaflets are computed during the coupling iterations. The Jacobian is numerically derived from the flow solver by applying leaflet perturbations. Instead of calculating this Jacobian every time step, the Jacobian is extrapolated from previous time steps and a recalculation of the Jacobian is only done when needed. The efficiency of our new algorithm is subsequently compared to existing algorithms which use fixed relaxation and dynamic Aitken Δ2 relaxation in the coupling iterations when the new positions of the leaflets are computed. Results show that dynamic Aitken Δ2 relaxation outperforms fixed relaxation. Moreover, during the opening phase of the valve, our new algorithm needs fewer subiterations per time step to achieve convergence than the method with Aitken Δ2 relaxation. Thus, our newly developed FSI coupling scheme outperforms the existing coupling schemes.

  10. Multivariate Normal Tissue Complication Probability Modeling of Heart Valve Dysfunction in Hodgkin Lymphoma Survivors

    Energy Technology Data Exchange (ETDEWEB)

    Cella, Laura, E-mail: laura.cella@cnr.it [Institute of Biostructures and Bioimaging, National Council of Research, Naples (Italy); Department of Advanced Biomedical Sciences, Federico II University School of Medicine, Naples (Italy); Liuzzi, Raffaele; Conson, Manuel [Institute of Biostructures and Bioimaging, National Council of Research, Naples (Italy); Department of Advanced Biomedical Sciences, Federico II University School of Medicine, Naples (Italy); D’Avino, Vittoria [Institute of Biostructures and Bioimaging, National Council of Research, Naples (Italy); Salvatore, Marco [Department of Advanced Biomedical Sciences, Federico II University School of Medicine, Naples (Italy); Pacelli, Roberto [Institute of Biostructures and Bioimaging, National Council of Research, Naples (Italy); Department of Advanced Biomedical Sciences, Federico II University School of Medicine, Naples (Italy)

    2013-10-01

    Purpose: To establish a multivariate normal tissue complication probability (NTCP) model for radiation-induced asymptomatic heart valvular defects (RVD). Methods and Materials: Fifty-six patients treated with sequential chemoradiation therapy for Hodgkin lymphoma (HL) were retrospectively reviewed for RVD events. Clinical information along with whole heart, cardiac chambers, and lung dose distribution parameters was collected, and the correlations to RVD were analyzed by means of Spearman's rank correlation coefficient (Rs). For the selection of the model order and parameters for NTCP modeling, a multivariate logistic regression method using resampling techniques (bootstrapping) was applied. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC). Results: When we analyzed the whole heart, a 3-variable NTCP model including the maximum dose, whole heart volume, and lung volume was shown to be the optimal predictive model for RVD (Rs = 0.573, P<.001, AUC = 0.83). When we analyzed the cardiac chambers individually, for the left atrium and for the left ventricle, an NTCP model based on 3 variables including the percentage volume exceeding 30 Gy (V30), cardiac chamber volume, and lung volume was selected as the most predictive model (Rs = 0.539, P<.001, AUC = 0.83; and Rs = 0.557, P<.001, AUC = 0.82, respectively). The NTCP values increase as heart maximum dose or cardiac chambers V30 increase. They also increase with larger volumes of the heart or cardiac chambers and decrease when lung volume is larger. Conclusions: We propose logistic NTCP models for RVD considering not only heart irradiation dose but also the combined effects of lung and heart volumes. Our study establishes the statistical evidence of the indirect effect of lung size on radio-induced heart toxicity.

  11. Hemodynamics of a functional centrifugal-flow total artificial heart with functional atrial contraction in goats.

    Science.gov (United States)

    Shiga, Takuya; Shiraishi, Yasuyuki; Sano, Kyosuke; Taira, Yasunori; Tsuboko, Yusuke; Yamada, Akihiro; Miura, Hidekazu; Katahira, Shintaro; Akiyama, Masatoshi; Saiki, Yoshikatsu; Yambe, Tomoyuki

    2016-03-01

    Implantation of a total artificial heart (TAH) is one of the therapeutic options for the treatment of patients with end-stage biventricular heart failure. There is no report on the hemodynamics of the functional centrifugal-flow TAH with functional atrial contraction (fCFTAH). We evaluated the effects of pulsatile flow by atrial contraction in acute animal models. The goats received fCFTAH that we created from two centrifugal-flow ventricular assist devices. Some hemodynamic parameters maintained acceptable levels: heart rate 115.5 ± 26.3 bpm, aortic pressure 83.5 ± 10.1 mmHg, left atrial pressure 18.0 ± 5.9 mmHg, pulmonary pressure 28.5 ± 9.7 mmHg, right atrial pressure 13.6 ± 5.2 mmHg, pump flow 4.0 ± 1.1 L/min (left) 3.9 ± 1.1 L/min (right), and cardiac index 2.13 ± 0.14 L/min/m(2). fCFTAH with atrial contraction was able to maintain the TAH circulation by forming a pulsatile flow in acute animal experiments. Taking the left and right flow rate balance using the low internal pressure loss of the VAD pumps may be easier than by other pumps having considerable internal pressure loss. We showed that the remnant atrial contraction effected the flow rate change of the centrifugal pump, and the atrial contraction waves reflected the heart rate. These results indicate that remnant atria had the possibility to preserve autonomic function in fCFTAH. We may control fCFTAH by reflecting the autonomic function, which is estimated with the flow rate change of the centrifugal pump. PMID:26198448

  12. Materials testing and requirements for the ERDA nuclear-powered artificial heart. Technical progress report, July 15, 1974--May 1, 1975

    International Nuclear Information System (INIS)

    Progress on the materials research and development effort for the ERDA-sponsored nuclear-powered artificial heart program is presented. Progress made during the first three years on hydrogel grafting and biological studies is summarized. Progress during the fourth year on studies of implanted artificial hearts, development of albumin surfaces, and in vitro mechanical studies is presented. (U.S.)

  13. Ultrasound-targeted transfection of tissue-type plasminogen activator gene carried by albumin nanoparticles to dog myocardium to prevent thrombosis after heart mechanical valve replacement

    Directory of Open Access Journals (Sweden)

    Ji J

    2012-06-01

    Full Text Available Ji Jun, Ji Shang-Yi, Yang Jian-An, He Xia, Yang Xiao-Han, Ling Wen-Ping, Chen Xiao-LingDepartment of Pathology and Cardiovascular Surgery, Shenzhen Sun Yat-Sen Cardiovascular Hospital, Shenzhen, Guangdong, People's Republic of ChinaBackground: There are more than 300,000 prosthetic heart valve replacements each year worldwide. These patients are faced with a higher risk of thromboembolic events after heart valve surgery and long-term or even life-long anticoagulative and antiplatelet therapies are necessary. Some severe complications such as hemorrhaging or rebound thrombosis can occur when the therapy ceases. Tissue-type plasminogen activator (t-PA is a thrombolytic agent. One of the best strategies is gene therapy, which offers a local high expression of t-PA over a prolonged time period to avoid both systemic hemorrhaging and local rebound thrombosis. There are some issues with t-PA that need to be addressed: currently, there is no up-to-date report on how the t-PA gene targets the heart in vivo and the gene vector for t-PA needs to be determined.Aims: To fabricate an albumin nano-t-PA gene ultrasound-targeted agent and investigate its targeting effect on prevention of thrombosis after heart mechanic valve replacement under therapeutic ultrasound.Methods: A dog model of mechanical tricuspid valve replacement was constructed. A highly expressive t-PA gene plasmid was constructed and packaged by nanoparticles prepared with bovine serum albumin. This nanopackaged t-PA gene plasmid was further cross-linked to ultrasonic microbubbles prepared with sucrose and bovine serum albumin to form the ultrasonic-targeted agent for t-PA gene transfection. The agent was given intravenously followed by a therapeutic ultrasound treatment (1 MHz, 1.5 w/cm2, 10 minutes of the heart soon after valve replacement had been performed. The expression of t-PA in myocardium was detected with multiclonal antibodies to t-PA by the indirect immunohistochemical method

  14. On intrinsic stress fiber contractile forces in semilunar heart valve interstitial cells using a continuum mixture model.

    Science.gov (United States)

    Sakamoto, Yusuke; Buchanan, Rachel M; Sacks, Michael S

    2016-02-01

    Heart valve interstitial cells (VICs) play a critical role in the maintenance and pathophysiology of heart valve tissues. Normally quiescent in the adult, VICs can become activated in periods of growth and disease. When activated, VICs exhibit increased levels of cytokines and extracellular matrix (ECM) synthesis, and upregulated expression and strong contraction of α-smooth muscle actin (α-SMA) fibers. However, it remains unknown how expression and contraction of the α-SMA fibers, which vary among different VIC types, contribute to the overall VIC mechanical responses, including the nucleus and cytoskeleton contributions. In the present study, we developed a novel solid-mixture model for VIC biomechanical behavior that incorporated 1) the underlying cytoskeletal network, 2) the oriented α-SMA stress fibers with passive elastic and active contractile responses, 3) a finite deformable elastic nucleus. We implemented the model in a full 3D finite element simulation of a VIC based on known geometry. Moreover, we examined the respective mechanical responses of aortic and pulmonary VICs (AVICs and PVICs, respectively), which are known to have different levels of α-SMA expression levels and contractile behaviors. To calibrate the model, we simulated the combined mechanical responses of VICs in both micropipette aspiration (MA) and atomic force microscopy (AFM) experiments. These two states were chosen as the VICs were under significantly different mechanical loading conditions and activation states, with the α-SMA fibers inactivated in the MA studies while fully activated in the AFM studies. We also used the AFM to study the mechanical property of the nucleus. Our model predicted that the substantial differences found in stiffening of the AVIC compared to the PVICs was due to a 9 to 16 times stronger intrinsic AVIC α-SMA stress fiber contractile force. Model validation was done by simulating a traction force microscopy experiment to estimate the forces the VICs

  15. Heat transport research and development for the nuclear powered artificial heart

    International Nuclear Information System (INIS)

    In the design and development of a nuclear-powered artificial heart, a heat rejection system is required to carry the waste heat from the thermal converter to the blood pumping unit. This heat rejection system must have high reliability, use a minimum of mechanical energy, have a small volume and weight, long life and be able to operate in any system orientation. A thermal oscillating pump (TOP) that meets these criteria is described. In the operation of the test loop, three modes of operation were identified. In the subcooled boiling mode, temperatures oscillated in the order of 2.8K and in the nucleate boiling mode the temperatures oscillated about 0.6K. The third mode (film boiling) occurred only at high power levels and this mode of operation is undesirable due to wide variations in temperature level

  16. Incompressible viscous flow computations for the pump components and the artificial heart

    Science.gov (United States)

    Kiris, Cetin

    1992-01-01

    A finite-difference, three-dimensional incompressible Navier-Stokes formulation to calculate the flow through turbopump components is utilized. The solution method is based on the pseudocompressibility approach and uses an implicit-upwind differencing scheme together with the Gauss-Seidel line relaxation method. Both steady and unsteady flow calculations can be performed using the current algorithm. In this work, the equations are solved in steadily rotating reference frames by using the steady-state formulation in order to simulate the flow through a turbopump inducer. Eddy viscosity is computed by using an algebraic mixing-length turbulence model. Numerical results are compared with experimental measurements and a good agreement is found between the two. Included in the appendix is a paper on incompressible viscous flow through artificial heart devices with moving boundaries. Time-accurate calculations, such as impeller and diffusor interaction, will be reported in future work.

  17. Heart failure analysis dashboard for patient's remote monitoring combining multiple artificial intelligence technologies.

    Science.gov (United States)

    Guidi, G; Pettenati, M C; Miniati, R; Iadanza, E

    2012-01-01

    In this paper we describe an Heart Failure analysis Dashboard that, combined with a handy device for the automatic acquisition of a set of patient's clinical parameters, allows to support telemonitoring functions. The Dashboard's intelligent core is a Computer Decision Support System designed to assist the clinical decision of non-specialist caring personnel, and it is based on three functional parts: Diagnosis, Prognosis, and Follow-up management. Four Artificial Intelligence-based techniques are compared for providing diagnosis function: a Neural Network, a Support Vector Machine, a Classification Tree and a Fuzzy Expert System whose rules are produced by a Genetic Algorithm. State of the art algorithms are used to support a score-based prognosis function. The patient's Follow-up is used to refine the diagnosis. PMID:23366362

  18. Nuclear-Powered Artificial Heart Prototype System Development Program: Phase III. Quarterly progress report, October 1, 1976--December 31, 1976

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Technical progress and accomplishments on the active program tasks 49 through 62 on the development of a nuclear-powered artificial heart are reported. The tasks include waste heat rejection, systems studies, IVBM modification design, IVBM fabrication, IVBM performance testing, IVBM system life testing, field support, reliability and quality assurance, Mark I thermal insulation design, and Mark I thermal converter design. (TFD)

  19. Elective Inactivation of Total Artificial Heart Technology in Non-Futile Situations: Inpatients, Outpatients and Research Participants

    Science.gov (United States)

    Bramstedt, Katrina A.

    2004-01-01

    Total artificial heart technology as a potential clinical therapy raises the issue of elective device inactivation in both futile and non-futile situations. This article explores elective device inactivation in non-futile situations. In reply to such requests for inactivation, the medical team should reflect on the individual's decision-making…

  20. Mitral valve regurgitation

    Science.gov (United States)

    ... MVP) Rare conditions, such as untreated syphilis or Marfan syndrome Rheumatic heart disease. This is a complication ... the arteries Heart failure - overview High blood pressure Marfan syndrome Mitral valve prolapse Pulmonary embolus Stroke Update ...

  1. Mitral valve regurgitation

    Science.gov (United States)

    ... valve prolapse (MVP) Rare conditions, such as untreated syphilis or Marfan syndrome Rheumatic heart disease. This is ... P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . 9th ed. Philadelphia, PA: Elsevier Saunders; 2011: ...

  2. Controle microbiológico em valvas cardíacas humanas Microbiologyc control in human heart valves

    Directory of Open Access Journals (Sweden)

    Angela Maria Peruzzo

    2006-12-01

    Full Text Available OBJETIVO: Avaliar, sob o aspecto microbiológico, valvas processadas pelo Banco de Valvas Cardíacas Humanas da Irmandade da Santa Casa de Misericórdia de Curitiba, para serem utilizadas em cirurgias cardiovasculares. MÉTODOS: Foi avaliado o processamento de 1.671 valvas, no período de junho de 1999 a junho de 2004. Das valvas e soluções envolvidas no processo foram coletadas amostras e semeadas nos meios de cultura: meio líquido tioglicolato, caldo soja tripticaseína e caldo Sabouraud, com quatorze dias de incubação, utilizando a metodologia modificada baseada na Farmacopéia Brasileira 1998 e USP 1990 (United States Pharmacopeia. Nas amostras que apresentaram crescimento foram realizadas as identificações microbianas. RESULTADOS: Em um total de 1.671 amostras analisadas, 92% foram consideradas próprias para utilização, sob o aspecto microbiológico, uma vez que não apresentaram contaminação microbiana. Somente 8% não foram liberadas para uso clínico por motivo de contaminação em alguma etapa do processamento da valva. CONCLUSÃO: Analisando os resultados, observou-se a importância do controle microbiológico em enxertos humanos, evitando a utilização de valvas com contaminação microbiológica em pacientes submetidos à cirurgia cardiovascular.OBJECTIVE: To evaluate, from microbiological point of view, the valves processed by Human Heart Valve Bank of Santa Casa de Misericórdia of Curitiba for use in cardiovascular surgeries. METHODS: The processing of 1,671 valves, accomplished within the period of time between July 1999 and June 2004, was evaluated. Out of the valves and the solutions involved in the process, samples were collected and spread in culture mediums, such as fluid thioglycollate medium, tryptic soy broth and Sabouraud broth, for incubation during 14 days, using a modified methodology based on the Farmacopéia Brasileira 1988 (Brazilian Pharmacopeia and USP 1990 (United States Pharmacopeia. The samples in

  3. Chest radiographic findings and complications of the temporary implantation of the Jarvik-7 artificial heart while awaiting orthotopic heart transplantation: Experience with five cases

    International Nuclear Information System (INIS)

    The Jarvik-7 artificial heart was originally introduced as a therapeutic alternative to cardiac transplantation in patients with endstage refractory cardiac disease. Its use has been expanded to those patients awaiting cardiac transplantation in whom death is impending and for whom a suitable donor match is unavailable. At Presbyterian-University Hospital of Pittsburgh five patients have had Jarvik-7 hearts implanted as a temporary measure while awaiting compatible donors for cardiac transplantation. The authors believe this is the largest patient group to undergo this procedure at a single institution. They present a brief description of the Jarvik-7 heart, the clinical factors affecting patient selection, and the radiographic appearance of a normally functioning Jarvik-7 heart, and review the chest radiographic complications seen in the patient group, along with eventual patient outcome

  4. Mitral valve repair and redo repair for mitral regurgitation in a heart transplant recipient

    Directory of Open Access Journals (Sweden)

    Bouma Wobbe

    2012-09-01

    Full Text Available Abstract A 37-year-old man with end-stage idiopathic dilated cardiomyopathy underwent an orthotopic heart transplant followed by a reoperation with mitral annuloplasty for severe mitral regurgitation. Shortly thereafter, he developed severe tricuspid regurgitation and severe recurrent mitral regurgitation due to annuloplasty ring dehiscence. The dehisced annuloplasty ring was refixated, followed by tricuspid annuloplasty through a right anterolateral thoracotomy. After four years of follow-up, there are no signs of recurrent mitral or tricupid regurgitation and the patient remains in NYHA class II. Pushing the envelope on conventional surgical procedures in marginal donor hearts (both before and after transplantation may not only improve the patient’s functional status and reduce the need for retransplantation, but it may ultimately alleviate the chronic shortage of donor hearts.

  5. Dynamic and fluid-structure interaction simulations of bioprosthetic heart valves using parametric design with T-splines and Fung-type material models

    Science.gov (United States)

    Hsu, Ming-Chen; Kamensky, David; Xu, Fei; Kiendl, Josef; Wang, Chenglong; Wu, Michael C. H.; Mineroff, Joshua; Reali, Alessandro; Bazilevs, Yuri; Sacks, Michael S.

    2015-06-01

    This paper builds on a recently developed immersogeometric fluid-structure interaction (FSI) methodology for bioprosthetic heart valve (BHV) modeling and simulation. It enhances the proposed framework in the areas of geometry design and constitutive modeling. With these enhancements, BHV FSI simulations may be performed with greater levels of automation, robustness and physical realism. In addition, the paper presents a comparison between FSI analysis and standalone structural dynamics simulation driven by prescribed transvalvular pressure, the latter being a more common modeling choice for this class of problems. The FSI computation achieved better physiological realism in predicting the valve leaflet deformation than its standalone structural dynamics counterpart.

  6. Validation of measurements of Fourier phase and amplitude analysis of technetium99 gated cardiac scans using artificial hearts

    International Nuclear Information System (INIS)

    The use of artificial hearts, developed for total heart replacement programs, allows assessment of the accuracy of measuring the first Fourier component phase and amplitude when applied to gated cardiac technetium 99 scans. In the extreme example of asynchrony of ventricular contraction in coronary artery disease that of ventricular aneurysms, the first Fourier component measurements of amplitude were highly correlated to volume increases suggesting that the calculated amplitude accurately reflects volume changes. The calculated asynchrony using Fourier analysis of the gated technetium 99 studies of two artificial hearts was highly accurate when compared to the predetermined calculation of phase angle difference and hence degree of asynchrony. The studies suggest that measurement of phase and amplitude using the first Fourier component of time-activity waves of gated cardiac technetium 99 studies accurately measure degree of asynchrony and volume changes respectively

  7. A moving-actuator type electromechanical total artificial heart--Part I: Linear type and mock circulation experiments.

    Science.gov (United States)

    Min, B G; Kim, H C; Lee, S H; Kim, J W; Kim, J T; Kim, I Y; Kim, S W; Diegel, P D; Olsen, D B

    1990-12-01

    A new type of motor-driven total artificial heart system with a moving-actuator mechanism has been developed. The prototype system consists of a brushless dc motor inside of a rolling-cylinder, two arc-shaped pusher-plates and two polyurethane sacs. The moving-actuator type electromechanical pump has structural advantages of small size and light weight, as compared to other reported motor-driven pumps with fixed-actuator mechanisms. The results of the mock circulation tests are reported in this paper with a cardiac output of 9 L/min at an aortic pressure of 120 mmHg and a heart rate of 120 bpm. The fulfillment of the basic control requirements of the artificial heart was also confirmed, i.e., preload sensitive and afterload insensitive cardiac output response and balanced right and left ventricular outputs. PMID:2289792

  8. Role of Computational Simulations in Heart Valve Dynamics and Design of Valvular Prostheses

    OpenAIRE

    Chandran, Krishnan B.

    2010-01-01

    Computational simulations are playing an increasingly important role in enhancing our understanding of the normal human physiological function, etiology of diseased states, surgical and interventional planning, and in the design and evaluation of artificial implants. Researchers are taking advantage of computational simulations to speed up the initial design of implantable devices before a prototype is developed and hence able to reduce animal experimentation for the functional evaluation of ...

  9. 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.

  10. Cytochrome P450 (CYP2C9FNx012,FNx013 & vitamin-K epoxide reductase complex (VKORC1 -1639G < A gene polymorphisms & their effect on acenocoumarol dose in patients with mechanical heart valve replacement

    Directory of Open Access Journals (Sweden)

    Anupriya Kaur

    2013-01-01

    Interpretation & conclusions: The study findings point towards the role of CYP2C9 and VKORC1 gene polymorphisms in determining the inter-individual dose variability of acenocoumarol in the Indian patients with mechanical heart valve replacement.

  11. Design and Control of a Transcutaneous Power Regulator for Artificial Heart

    Directory of Open Access Journals (Sweden)

    Ms. R. Kasthuri

    2014-02-01

    Full Text Available In medical implant systems high efficiency and improving the patient’s mobility. Artificial organs and monitoring devices to be implanted into human body for the extension and the improvement of human lives. The implants must operate inside the body for the considerable period of time and communicate with outside world wirelessly for exchange of medical data and commands. Rechargeable batteries are recharged remotely through the human skin via inductive links. In my project transformer model a remote power supply for use in the artificial hearts for easy controllability and high efficiency, which can monitor the charging level of the battery has been designed and implemented. In order to recharge the battery the electro-magnetic coupling between primary coil and secondary coil has been used. Primary and secondary windings of the transformer are positioned outside and inside the human body respectively. In such a transformer, the alignment and gap may change with external positioning. The coupling coefficient of the transformer is also varying, and so are the tool to large leakage inductances and the mutual inductance. Resonance-tank circuits with varying resonance frequency are formed from the transformer inductors and external capacitors. A control method is proposed to lock the switching frequency at just above the load insensitive frequency for optimized efficiency at heavy loads. Specifically operation at above resonant of the resonance circuits is maintained under varying coupling coefficient. A transcutaneous power regulator is built and found to perform excellently with high efficiency and tight regulation under variations of the alignment or gap of the transcutaneous transformer load and input voltage.

  12. Diseases of the Tricuspid Valve

    Science.gov (United States)

    ... Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden Cardiac Arrest Valve Disease Vulnerable Plaque Diseases of the Tricuspid Valve | Share Diseases of the heart valves are grouped according to which valve or ...

  13. Transcatheter CoreValve valve-in-valve implantation in a stentless porcine aortic valve for severe aortic regurgitation

    OpenAIRE

    Yong, Celina M; Buchbinder, Maurice; Giacomini, John C

    2014-01-01

    Key Clinical Message We describe the first valve-in-valve Corevalve transcatheter aortic valve replacement in the St. Jude Toronto stentless porcine aortic valve in the United States, which enabled this 59-year-old patient with a history of bacterial endocarditis and aortic regurgitation to avoid heart transplant with complete resolution of his severe left ventricular dysfunction.

  14. Left Main Percutaneous Coronary Intervention and Transcatheter Aortic Valve Replacement in a Young Male with Rheumatic Heart Disease and Porcelain Aorta

    OpenAIRE

    Chainani, Vinod; Perez, Osman; Hanno, Ram; Hourani, Patrick; Rengifo-Moreno, Pablo; Martinez-Clark, Pedro; Alfonso, Carlos E.

    2016-01-01

    We highlight the presence of a calcified mass in the left main coronary artery without significant atherosclerosis seen in the other coronary arteries or in the peripheral large arteries. In our view, the calcified character of the obstruction and the calcification of the aortic valve are characteristic of a variant type of coronary artery disease (CAD) not associated with the same risk factors as diffuse coronary atherosclerosis, but, in this case, with rheumatic heart disease. This case rep...

  15. Patient-Reported Outcome Measures (PROMS) in patients undergoing heart valve surgery: why should we measure them and which instruments should we use?

    OpenAIRE

    Holmes, Charlotte; Briffa, Norman

    2016-01-01

    Objective As the population ages, the incidence of heart valve disease (HVD) is increasing. The aim of treatment is to improve prognosis and quality of life. Standard surgical treatment is being superseded by new catheter-based treatments, many of which are as yet unproven. The need for appropriate instruments to measure quality of life in patients receiving treatment for HVD has therefore never been greater. Methods In this prospective observational study, a generic instrument, Euroqol, and ...

  16. Closing sounds and related complaints after heart valve replacement with St Jude Medical, Duromedics Edwards, Björk-Shiley Monostrut, and Carbomedics prostheses.

    OpenAIRE

    Moritz, A.; Steinseifer, U; Kobinia, G; Neuwirth-Riedl, K; Wolters, H.; H. Reul; Wolner, E

    1992-01-01

    OBJECTIVE--To measure the noise produced and related subjective complaints after implantation of four different mechanical heart valve prostheses and to identify further factors related to the patient and prosthesis that influence noise generation and complaints. DESIGN--Sound pressure was measured 5 and 10 cm and 1 m from the point of maximal impulse on the body surface by a calibrated meter in quiet rooms with either a decibel(A) filter or octave filters. The patients were asked about their...

  17. Effect of Hinge Gap Width of a St. Jude Medical Bileaflet Mechanical Heart Valve on Blood Damage Potential—An In Vitro Micro Particle Image Velocimetry Study

    OpenAIRE

    Jun, Brian H.; Saikrishnan, Neelakantan; Arjunon, Sivakkumar; Min Yun, B.; Yoganathan, Ajit P.

    2014-01-01

    The hinge regions of the bileaflet mechanical heart valve (BMHV) can cause blood element damage due to nonphysiological shear stress levels and regions of flow stasis. Recently, a micro particle image velocimetry (μPIV) system was developed to study whole flow fields within BMHV hinge regions with enhanced spatial resolution under steady leakage flow conditions. However, global velocity maps under pulsatile conditions are still necessary to fully understand the blood damage potential of these...

  18. Eliminating artificial trans fatty acids in Argentina: estimated effects on the burden of coronary heart disease and costs

    OpenAIRE

    2015-01-01

    Abstract Objective To estimate the impact of Argentine policies to reduce trans fatty acids (TFA) on coronary heart disease (CHD), disability-adjusted life years (DALYs) and associated health-care costs. Methods We estimated the baseline intake of TFA before 2004 to be 1.5% of total energy intake. We built a policy model including baseline intake of TFA, the oils and fats used to replace artificial TFAs, the clinical effect of reducing artificial TFAs and the costs and DALYs saved due to aver...

  19. Biomarkers in Cardiology - Part 2: In Coronary Heart Disease, Valve Disease and Special Situations

    Directory of Open Access Journals (Sweden)

    2015-05-01

    Full Text Available Cardiovascular diseases are the main causes of mortality and morbidity in Brazil. Their primary and secondary preventions are a priority for the health system and require multiple approaches for increased effectiveness. Biomarkers are tools used to identify with greater accuracy high-risk individuals, establish a faster diagnosis, guide treatment, and determine prognosis. This review aims to highlight the importance of biomarkers in clinical cardiology practice and raise relevant points regarding their application and perspectives for the next few years. This document was divided into two parts. This second part addresses the application of biomarkers in coronary heart disease, valvular diseases, cardio-oncology, pulmonary embolism, and cardiorenal syndrome.

  20. Simulation of the three-dimensional hinge flow fields of a bileaflet mechanical heart valve under aortic conditions.

    Science.gov (United States)

    Simon, Hélène A; Ge, Liang; Borazjani, Iman; Sotiropoulos, Fotis; Yoganathan, Ajit P

    2010-03-01

    Thromboembolic complications of bileaflet mechanical heart valves (BMHV) are believed to be due to detrimental stresses imposed on blood elements by the hinge flows. Characterization of these flows is thus crucial to identify the underlying causes for complications. In this study, we conduct three-dimensional pulsatile flow simulations through the hinge of a BMHV under aortic conditions. Hinge and leaflet geometries are reconstructed from the Micro-Computed Tomography scans of a BMHV. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Physiologic flow boundary conditions and leaflet motion are extracted from the Fluid-Structure Interaction simulations of the bulk of the flow through a BMHV. Calculations reveal the presence, throughout the cardiac cycle, of flow patterns known to be detrimental to blood elements. Flow fields are characterized by: (1) complex systolic flows, with rotating structures and slow reverse flow pattern, and (2) two strong diastolic leakage jets accompanied by fast reverse flow at the hinge bottom. Elevated shear stresses, up to 1920 dyn/cm2 during systole and 6115 dyn/cm2 during diastole, are reported. This study underscores the need to conduct three-dimensional simulations throughout the cardiac cycle to fully characterize the complexity and thromboembolic potential of the hinge flows. PMID:19960368

  1. Multi-Targeted Antithrombotic Therapy for Total Artificial Heart Device Patients.

    Science.gov (United States)

    Ramirez, Angeleah; Riley, Jeffrey B; Joyce, Lyle D

    2016-03-01

    To prevent thrombotic or bleeding events in patients receiving a total artificial heart (TAH), agents have been used to avoid adverse events. The purpose of this article is to outline the adoption and results of a multi-targeted antithrombotic clinical procedure guideline (CPG) for TAH patients. Based on literature review of TAH anticoagulation and multiple case series, a CPG was designed to prescribe the use of multiple pharmacological agents. Total blood loss, Thromboelastograph(®) (TEG), and platelet light-transmission aggregometry (LTA) measurements were conducted on 13 TAH patients during the first 2 weeks of support in our institution. Target values and actual medians for postimplant days 1, 3, 7, and 14 were calculated for kaolinheparinase TEG, kaolin TEG, LTA, and estimated blood loss. Protocol guidelines were followed and anticoagulation management reduced bleeding and prevented thrombus formation as well as thromboembolic events in TAH patients postimplantation. The patients in this study were susceptible to a variety of possible complications such as mechanical device issues, thrombotic events, infection, and bleeding. Among them all it was clear that patients were at most risk for bleeding, particularly on postoperative days 1 through 3. However, bleeding was reduced into postoperative days 3 and 7, indicating that acceptable hemostasis was achieved with the anticoagulation protocol. The multidisciplinary, multi-targeted anticoagulation clinical procedure guideline was successful to maintain adequate antithrombotic therapy for TAH patients. PMID:27134306

  2. Artificial heart development program. Volume I. System development. Phase III summary report

    International Nuclear Information System (INIS)

    The report documents efforts and results in the development of the power system portions of a calf implantable model of nuclear-powered artificial heart. The primary objective in developing the implantable model was to solve the packaging problems for total system implantation. The power systems portion is physically that portion of the implantable model between the Pu-238 heat sources and the blood pump ventricles. The work performed had two parallel themes. The first of these was the development of an integrated implantable model for bench and animal experiments plus design effort on a more advanced model. The second was research and development on components of the system done in conjunction with the development of the implantable model and to provide technology for incorporation into advanced models plus support to implantations, at the University of Utah, of the systems blood pumping elements when driven by electric motor. The efforts and results of implantable model development are covered, mainly, in the text of the report. The research and development efforts and results are reported, primarily, in the appendices

  3. Artificial heart development program. Volume I. System development. Phase III summary report

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    The report documents efforts and results in the development of the power system portions of a calf implantable model of nuclear-powered artificial heart. The primary objective in developing the implantable model was to solve the packaging problems for total system implantation. The power systems portion is physically that portion of the implantable model between the Pu-238 heat sources and the blood pump ventricles. The work performed had two parallel themes. The first of these was the development of an integrated implantable model for bench and animal experiments plus design effort on a more advanced model. The second was research and development on components of the system done in conjunction with the development of the implantable model and to provide technology for incorporation into advanced models plus support to implantations, at the University of Utah, of the systems blood pumping elements when driven by electric motor. The efforts and results of implantable model development are covered, mainly, in the text of the report. The research and development efforts and results are reported, primarily, in the appendices (Vol. 2).

  4. A meso-scale layer-specific structural constitutive model of the mitral heart valve leaflets.

    Science.gov (United States)

    Zhang, Will; Ayoub, Salma; Liao, Jun; Sacks, Michael S

    2016-03-01

    Fundamental to developing a deeper understanding of pathophysiological remodeling in mitral valve (MV) disease is the development of an accurate tissue-level constitutive model. In the present work, we developed a novel meso-scale (i.e. at the level of the fiber, 10-100μm in length scale) structural constitutive model (MSSCM) for MV leaflet tissues. Due to its four-layer structure, we focused on the contributions from the distinct collagen and elastin fiber networks within each tissue layer. Requisite collagen and elastin fibrous structural information for each layer were quantified using second harmonic generation microscopy and conventional histology. A comprehensive mechanical dataset was also used to guide model formulation and parameter estimation. Furthermore, novel to tissue-level structural constitutive modeling approaches, we allowed the collagen fiber recruitment function to vary with orientation. Results indicated that the MSSCM predicted a surprisingly consistent mean effective collagen fiber modulus of 162.72MPa, and demonstrated excellent predictive capability for extra-physiological loading regimes. There were also anterior-posterior leaflet-specific differences, such as tighter collagen and elastin fiber orientation distributions (ODF) in the anterior leaflet, and a thicker and stiffer atrialis in the posterior leaflet. While a degree of angular variance was observed, the tight valvular tissue ODF also left little room for any physically meaningful angular variance in fiber mechanical responses. Finally, a novel fibril-level (0.1-1μm) validation approach was used to compare the predicted collagen fiber/fibril mechanical behavior with extant MV small angle X-ray scattering data. Results demonstrated excellent agreement, indicating that the MSSCM fully captures the tissue-level function. Future utilization of the MSSCM in computational models of the MV will aid in producing highly accurate simulations in non-physiological loading states that can

  5. Magnetic-Field Immunity Examination and Evaluation of Transcutaneous Energy-Transmission System for a Totally Implantable Artificial Heart

    Directory of Open Access Journals (Sweden)

    Takahiko Yamamoto

    2012-01-01

    Full Text Available Transcutaneous energy transmission (TET is the most promising noninvasive method for supplying driving energy to a totally implantable artificial heart. Induction-heating (IH cookers generate a magnetic flux, and if a cooker is operated near a transcutaneous transformer, the magnetic flux generated will link with its external and internal coils. This will affect the performance of the TET and the artificial heart system. In this paper, we present the design and development of a coil to be used for a magnetic immunity test, and we detail the investigation of the magnetic immunity of a transcutaneous transformer. The experimental coil, with five turns like a solenoid, was able to generate a uniform magnetic field in the necessary bandwidth. A magnetic-field immunity examination of the TET system was performed using this coil, and the system was confirmed to have sufficient immunity to the magnetic field generated as a result of the conventional operation of induction-heating cooker.

  6. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... a chronic disease process of inflammation and protein deposition that ultimately results in calcification of the valve. ... heart valve which is made out of pyrolitic carbon, basically metal and plastic. Again, blood flows through ...

  7. Swan-Ganz - right heart catheterization

    Science.gov (United States)

    ... have: Abnormal pressures in the heart arteries Burns Congenital heart disease Heart failure Kidney disease Leaky heart valves (valvular ... 2011:chap 55. Read More Burns Cardiac tamponade Congenital heart disease Heart attack Heart failure - overview Pulmonary hypertension Restrictive ...

  8. Using Clinical Decision Support and Dashboard Technology to Improve Heart Team Efficiency and Accuracy in a Transcatheter Aortic Valve Implantation (TAVI) Program.

    Science.gov (United States)

    Clarke, Sarah; Wilson, Marisa L; Terhaar, Mary

    2016-01-01

    Heart Team meetings are becoming the model of care for patients undergoing transcatheter aortic valve implantations (TAVI) worldwide. While Heart Teams have potential to improve the quality of patient care, the volume of patient data processed during the meeting is large, variable, and comes from different sources. Thus, consolidation is difficult. Also, meetings impose substantial time constraints on the members and financial pressure on the institution. We describe a clinical decision support system (CDSS) designed to assist the experts in treatment selection decisions in the Heart Team. Development of the algorithms and visualization strategy required a multifaceted approach and end-user involvement. An innovative feature is its ability to utilize algorithms to consolidate data and provide clinically useful information to inform the treatment decision. The data are integrated using algorithms and rule-based alert systems to improve efficiency, accuracy, and usability. Future research should focus on determining if this CDSS improves patient selection and patient outcomes. PMID:27332170

  9. A novel permanent magnetic bearing and its anti-wear effect in impeller total artificial heart

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel permanent magnetic bearing has been developed, which consists of two magnetic rings with different dimensions in the same direction of axial magnetization, located concentrically. Because of the effect of magnetic field, the magnetic rings keep a distance axially from each other. If the distance between the two rings changes, a rehabilitation force is produced to return to the original position. When this distance decreases, a repelling force will be generated; its component in axial direction can be used as a magnetic spring and its radial component can function as a bearing. With this novel permanent magnetic bearing, an impeller total artificial heart (TAH) is designed, manufactured and tested. The rotation is driven radially. On the left and right sides of the rotor magnets, two small magnetic rings are fixed onto the rotor, coupling with two big magnetic rings on both sides of the motor coil, to form the magnetic bearings. Hereby the bearings are used for wear reduction rather than rotor levitation. That means the magnetic bearings counteract the attractive force between the motor coil iron and rotor magnets so as to reduce the friction between the motor stator and rotor. At the left and right ends of the rotor, two impellers with the same width but different diameters are mounted. Thus the device has only one moving part-rotor; both the left pump and the right pump eject the blood synchronically; the volume equilibrium of both pumps can be achieved automatically without need of control. The device weighing 250 g has a length of 60 mm and a diameter of 40 mm at its largest point, and can produce a blood flow up to 150 mm Hg and 6 L/min from left pump, 50 mm Hg and 6 L/min from right pump, at rotating speed of 4000 r/min of the motor. The consumed power is under 10 W.

  10. Left and right pump output control in one-piece electromechanical total artificial heart.

    Science.gov (United States)

    Takatani, S; Shiono, M; Sasaki, T; Orime, Y; Sakuma, I; Noon, G; Nosé, Y; DeBakey, M

    1993-03-01

    Left master alternate (LMA) ejection control based on the left pump fill method was implemented for a one-piece electromechanical total artificial heart (TAH). The TAH consists of left and right pusher-plate-type blood pumps sandwiching a compact electromechanical actuator comprising a direct current (DC) brushless motor and a planetary roller screw. The motor rotation is controlled on the basis of the roller-screw position as detected by a Hall effect sensor and a commutation pulse counting method. Since the pusher-plate shaft and roller screw are decoupled during filling, both pumps fill passively with the right and left atrial pressure. To obtain response to the right atrial pressure change in the LMA mode, the left fill trigger level as detected by a Hall effect position sensor is adjusted to operate the pump at a higher rate and to drive the right pump at 85-90% of the full stroke level. The in vitro evaluation demonstrated that this method can respond to right atrial pressure changes provided that the right pump is operated at less than the full stroke level. When the preload is high and the right pump goes into full stroke operation, the left eject level can be decreased to run the pump at a higher rate and to transfer more blood from the right to the left. In the in vivo evaluation, which lasted 1 week in a 95 kg calf, the left and right atrial pressures were kept within physiological ranges.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8215943

  11. Ultracompact, completely implantable permanent use electromechanical ventricular assist device and total artificial heart.

    Science.gov (United States)

    Honda, N; Inamoto, T; Nogawa, M; Takatani, S

    1999-03-01

    An ultracompact, completely implantable permanent use electromechanical ventricular assist device (VAD) and total artificial heart (TAH) intended for 50-60 kg size patients have been developed. The TAH and VAD share a miniature electromechanical actuator that comprises a DC brushless motor and a planetary roller screw. The rotational force of the motor is converted into the rectilinear force of the roller screw to actuate the blood pump. The TAH is a one piece design with left and right pusher plate type blood pumps sandwiching an electromechanical actuator. The VAD is one half of the TAH with the same actuator but a different pump housing and a backplate. The blood contacting surfaces, including those of the flexing diaphragm and pump housing, of both the VAD and TAH were made of biocompatible polyurethane. The diameter, thickness, volume, and weight of the VAD are 90 mm, 56 mm, 285 cc, and 380 g, respectively, while those of the TAH are 90 mm, 73 mm, 400 cc, and 440 g, respectively. The design stroke volume of both the VAD and TAH is 60 cc with the stroke length being 12 mm. The stroke length and motor speed are controlled solely based on the commutation signals of the motor. An in vitro study revealed that a maximum pump flow of 7.5 L/min can be obtained with a pump rate of 140 bpm against a mean afterload of 100 mm Hg. The power requirement ranged from 4 to 6 W to deliver a 4-5 L/min flow against a 100 mm Hg afterload with the electrical-to-hydraulic efficiency being 19-20%. Our VAD and TAH are the smallest of the currently available devices and suitable for bridge to transplant application as well as for permanent circulatory support of 50-60 kg size patients. PMID:10198717

  12. Perioperative Anticoagulation in Patients with Mechanical Heart Valves Undergoing Elective Surgery: Results of a Survey Conducted among Korean Physicians

    Science.gov (United States)

    Kim, Sehyun; Lim, Chang Young; Lee, Jong Seok; Park, Seonyang; Garcia, David; Crowther, Mark A.; Ageno, Walter

    2005-01-01

    The optimal perioperative anticoagulation management in patients on warfarin therapy is poorly defined due to the lack of randomized trials. Because guidelines are heterogeneous, it was hypothesized that "treatment strategies are not uniform in clinical practice". Between February 2003 and May 2003, a questionnaire with 4 different clinical scenarios was distributed to physicians by e-mail, or direct contact was made by a survey monitor. Two scenarios described the cases of patients with a mechanical heart valve (MHV) in the mitral position, with additional risk factors for a systemic embolism; one undergoing major (scenario 1) and the other minor surgery (scenario 3). Two scenarios described patients with an aortic MHV; one undergoing major (scenario 2) and the other minor (scenario 4) surgery. Different preoperative and postoperative management options were offered. The treatment options for all scenarios were the same. Of the 90 questionnaires distributed, 52 (57.8%) were returned. Hospitalization for full-dose intravenous unfractionated heparin (IV UH) was the most commonly selected strategy in the preoperative phase for scenarios 1 (59%), 2 (42%) and 3 (44%). In scenario 4, 34% chose IV UH. Outpatient, full-dose, subcutaneous UH or low-molecular-weight heparin (LMWH) was the most selected option in the postoperative phase for all scenarios, with the exception of number 4 (52.9% in scenario 1, 34% in scenario 2, 32%, in scenario 3 and 28% in scenario 4). Even among expert clinicians, the management of perioperative anticoagulation is heterogeneous. In particular, the definition of risk categories and the optimal intensity of antithrombotic drugs need to be defined by well-designed prospective studies. PMID:15744807

  13. Strategies and outcomes of periprocedural bridging therapy with low-molecular-weight heparin in patients with mechanical heart valves.

    Science.gov (United States)

    Schulman, Jacqueline M; Majeed, Ammar; Mattsson, Eva; Schulman, Sam; Holmström, Margareta; Ågren, Anna

    2015-11-01

    Patients with mechanical heart valves (MHV) undergoing invasive procedures often receive periprocedural bridging with low-molecular-weight heparin (LMWH). The bridging strategies used in real-life and the predictors for bleeding and thrombosis are not well studied. We retrospectively assessed patients with MHV that underwent invasive procedures requiring vitamin K antagonist interruption and LMWH bridging. Thromboembolic and bleeding events occurring up to 30 days after the procedures were recorded. Predictors of major bleeding events (MBEs) were analyzed with logistic regression. We evaluated 547 patients with MHV who underwent 275 procedures during a 6.5-year period. Bridging with LMWH was used in 185 procedures in a total of 117 patients. Combined pre- and post-operative bridging was the most frequently employed (63 %). Doses of LMWH were prophylactic in 96 (52 %) of the procedures and therapeutic in 89 (48 %). The procedure-related bleeding risk was evaluated as high in 70 (38 %) and low in 115 (62 %) of the procedures. There was a trend to more frequent use of prophylactic doses (61 %) in high-risk surgery, and more therapeutic doses (53 %) in low-risk ones. There were 36 bleeding episodes, 21 (11 % of procedures) of which were classified as MBEs, but there were no thromboembolic events. Most MBEs (n = 14; 67 %) occurred in surgeries with high bleeding risk. In the multivariate analysis, the bleeding risk of the surgery itself was the only independent predictor for MBEs. For patients with MHV receiving perioperative bridging with LMWH, the major predictor for MBE is the bleeding risk of the surgery. PMID:25868460

  14. Safety and Cost-Effectiveness of Bridge Therapies for Invasive Dental Procedures in Patients with Mechanical Heart Valves

    Science.gov (United States)

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

    2014-01-01

    Purpose Bridge anticoagulation therapy is mostly utilized in patients with mechanical heart valves (MHV) receiving warfarin therapy during invasive dental procedures because of the risk of excessive bleeding related to highly vascular supporting dental structures. Bridge therapy using low molecular weight heparin may be an attractive option for invasive dental procedures; however, its safety and cost-effectiveness compared with unfractionated heparin (UFH) is uncertain. Materials and Methods This study investigated the safety and cost-effectiveness of enoxaparin in comparison to UFH for bridge therapy in 165 consecutive patients (57±11 years, 35% men) with MHV who underwent invasive dental procedures. Results This study included 75 patients treated with UFH-based bridge therapy (45%) and 90 patients treated with enoxaparin-based bridge therapy (55%). The bleeding risk of dental procedures and the incidence of clinical adverse outcomes were not significantly different between the UFH group and the enoxaparin group. However, total medical costs were significantly lower in the enoxaparin group than in the UFH group (p<0.001). After multivariate adjustment, old age (≥65 years) was significantly associated with an increased risk of total bleeding independent of bridging methods (odds ratio, 2.51; 95% confidence interval, 1.15-5.48; p=0.022). Enoxaparin-based bridge therapy (β=-0.694, p<0.001) and major bleeding (β=0.296, p=0.045) were significantly associated with the medical costs within 30 days after dental procedures. Conclusion Considering the benefit of enoxaparin in cost-effectiveness, enoxaparin may be more efficient than UFH for bridge therapy in patients with MHV who required invasive dental procedures. PMID:24954321

  15. Heart murmurs and other sounds

    Science.gov (United States)

    Chest sounds - murmurs; Heart sounds - abnormal; Murmur - innocent; Innocent murmur; Systolic heart murmur; Diastolic heart murmur ... The heart has four chambers: Two upper chambers (atria) Two lower chambers (ventricles) The heart has valves that close ...

  16. Clinical Analysis of Rheumatic Heart Valve Disease%风湿性心瓣膜病的临床观察分析

    Institute of Scientific and Technical Information of China (English)

    马大为

    2015-01-01

    ObjectiveTo study the analysis of rheumatic heart valve disease clinical manifestation, clinical treatment measures and effects.Methods Selected in our hospital in 2013 June to 2014 July were 24 cases of rheumatic valvular heart diseasepatients, the clinical data of the patients were retrospectively analyzed.ResultsRheumatic heart valve with coronary heart disease were 66.7% (16/24). Rheumatic heart valve with diabetes mellitus, hypertension was 20.8% (5/24), 12.5% (3/24). At the same time, a longer duration of patients and elderly patients with coronary heart disease and the proportion of larger; with a history of diabetes mellitus, hypertension patients with coronary heart disease probability is big; the old patients with hypertension and diabetic on has a strong role in promoting the occurrence of coronary heart disease.Conclusion Through the analysis and Study on rheumatic valvular disease, the main cause of coronary heart disease is the formation of rheumatic heart valve in patients with diabetes and hypertension disease causes, or merged with two kinds of diseases in a cause.%目的:研究分析风湿性心瓣膜病的临床表现、临床治疗措施和效果。方法选取我院2013年6月至2014年7月收治的24例风湿性心瓣膜病的患者,对患者的临床资料进行回顾性分析。结果风湿性心瓣膜合并冠心病的患者66.7%(16/24)。风湿性心瓣膜合并糖尿病、高血压为20.8%(5/24)、12.5%(3/24)。同时,病程较长的患者和高龄冠心病患者所占的比例较大;具有高血压、糖尿病史的患者患有冠心病的概率较大;高龄合并高血压以及糖尿病对冠心病的发生具有较强的促进作用。结论通过对风湿性心瓣膜疾病的分析和观察研究,冠心病主要形成的原因是风湿性心瓣膜患者合并糖尿病和高血压疾病导致,或者是合并两种疾病中的一种导致的。

  17. Effect of hinge gap width of a St. Jude medical bileaflet mechanical heart valve on blood damage potential--an in vitro micro particle image velocimetry study.

    Science.gov (United States)

    Jun, Brian H; Saikrishnan, Neelakantan; Arjunon, Sivakkumar; Yun, B Min; Yoganathan, Ajit P

    2014-09-01

    The hinge regions of the bileaflet mechanical heart valve (BMHV) can cause blood element damage due to nonphysiological shear stress levels and regions of flow stasis. Recently, a micro particle image velocimetry (μPIV) system was developed to study whole flow fields within BMHV hinge regions with enhanced spatial resolution under steady leakage flow conditions. However, global velocity maps under pulsatile conditions are still necessary to fully understand the blood damage potential of these valves. The current study hypothesized that the hinge gap width will affect flow fields in the hinge region. Accordingly, the blood damage potential of three St. Jude Medical (SJM) BMHVs with different hinge gap widths was investigated under pulsatile flow conditions, using a μPIV system. The results demonstrated that the hinge gap width had a significant influence during the leakage flow phase in terms of washout and shear stress characteristics. During the leakage flow, the largest hinge gap generated the highest Reynolds shear stress (RSS) magnitudes (~1000 N/m²) among the three valves at the ventricular side of the hinge. At this location, all three valves indicated viscous shear stresses (VSS) greater than 30 N/m². The smallest hinge gap exhibited the lowest level of shear stress values, but had the poorest washout flow characteristics among the three valves, demonstrating propensity for flow stasis and associated activated platelet accumulation potential. The results from this study indicate that the hinge is a critical component of the BMHV design, which needs to be optimized to find the appropriate balance between reduction in fluid shear stresses and enhanced washout during leakage flow, to ensure minimal thrombotic complications. PMID:24976188

  18. Update to the study protocol, including statistical analysis plan for a randomized clinical trial comparing comprehensive cardiac rehabilitation after heart valve surgery with control

    DEFF Research Database (Denmark)

    Sibilitz, Kirstine Laerum; Berg, Selina Kikkenborg; Hansen, Tina Birgitte;

    2015-01-01

    cost-benefit will be assessed. A mixed-method design will be used to evaluate qualitative and quantitative findings, encompassing a survey-based study before the trial and a qualitative pre- and post-intervention study. CONCLUSION: This randomized clinical trial will contribute with evidence of whether...... cardiac rehabilitation should be provided after heart valve surgery. The study is approved by the local regional Research Ethics Committee (H-1-2011-157), and the Danish Data Protection Agency (j.nr. 2007-58-0015). TRIAL REGISTRATION: Trial registered 16 March 2012; ClinicalTrials.gov ( NCT01558765 )....

  19. Artificial heart development program. Volume I. System development. Phase III summary report, July 1, 1973--September 30, 1977

    International Nuclear Information System (INIS)

    Efforts and results in the development of the power system portions of a calf implantable model of nuclear-powered artificial heart are discussed. The primary objective in developing the implantable model was to solve the packaging problems for total system implantation. The power system's portion is physically that portion of the implantable model between the 238Pu heat sources and the blood pump ventricles. The 238Pu heat sources and blood pump ventricles were provided as Government Furnished Equipment as developed and fabricated by other contractors

  20. Artificial heart development program. Volume I. System development. Phase III summary report, July 1, 1973--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Efforts and results in the development of the power system portions of a calf implantable model of nuclear-powered artificial heart are discussed. The primary objective in developing the implantable model was to solve the packaging problems for total system implantation. The power system's portion is physically that portion of the implantable model between the /sup 238/Pu heat sources and the blood pump ventricles. The /sup 238/Pu heat sources and blood pump ventricles were provided as Government Furnished Equipment as developed and fabricated by other contractors.

  1. Influência de válvulas artificiais sobre a morfometria intestinal de ratos Influence of artificial valves on the intestinal morphology of rats

    Directory of Open Access Journals (Sweden)

    Maria Cristina Vasconcelos Furtado

    2008-10-01

    Full Text Available OBJETIVO: Avaliar o papel de válvulas artificiais constituídas por seromiotomias circunferenciais duplas no comprimento dos vilos, no diâmetro do intestino delgado e no peso de ratos. MÉTODO: Foram utilizados 40 ratos, distribuídos em quatro grupos. Os animais do Grupo R foram submetidos à ressecção de 50% do intestino delgado, sem criação de válvulas. No Grupo RV associaram duas válvulas à ressecção intestinal. No Grupo V foram criadas duas válvulas, sem ressecção intestinal. O Grupo C forneceu a altura normal dos vilos. A eutanásia deu-se entre o décimo e o 14º dia pós-operatórios. RESULTADOS: Houve aumento no comprimento dos vilos nos grupos R, RV e V. Comparado ao Grupo R, o comprimento dos vilos nos grupos RV e V foi semelhante nos segmentos proximal e distal. No Grupo RV, os vilos do segmento proximal tiveram comprimento superior ao do distal. No Grupo V, o comprimento dos vilos do segmento proximal foi menor que do distal. A alça intestinal teve diâmetro maior que no pré-operatório no Grupo R e nos segmentos proximal à primeira válvula e distal à segunda, dos grupos RV e V. A ressecção intestinal levou à perda ponderal nos grupos R e RV, sem diferença entre os grupos. No Grupo V houve ganho de peso, significativo quando comparado aos grupos R e RV. Apesar de não impedirem a perda ponderal em animais submetidos à ressecção, as válvulas não determinaram perda superior à da ressecção isolada. CONCLUSÃO: Essas válvulas parecem influenciar positivamente a adaptação intestinal e podem ser incluídas entre as técnicas de reabilitação intestinal cirúrgica, isoladamente ou precedendo intervenções de alongamento do intestino.BACKGROUND: to evaluate the role of artificial valves created by double circumferential seromyotomies in the villi length, in the small intestine diameter and in the weight of rats. METHOD: 40 rats have been distributed into four groups. The R Group animals were submitted to

  2. Cardiopulmonary exercise testing responses to different external portable drivers in a patient with a CardioWest Total Artificial Heart.

    Science.gov (United States)

    Tarzia, Vincenzo; Braccioni, Fausto; Bortolussi, Giacomo; Buratto, Edward; Gallo, Michele; Bottio, Tomaso; Vianello, Andrea; Gerosa, Gino

    2016-06-01

    Management of patients treated with CardioWest Total Artificial Heart (CW-TAH) as a bridge to heart transplantation (HTx) is complicated by difficulties in determining the optimal timing of transplantation. We present a case of a 53-year-old man supported as an outpatient with a CW-TAH, whose condition deteriorated following exchange of the portable driver. The patient was followed-up with serial cardiopulmonary exercise testing (CPET) which demonstrated a fall of peak VO2 to below 12 ml/kg/min following driver substitution, and the patient was subsequently treated with urgent orthotopic HTx. This case highlights the potential utility of CPET as a means for monitoring and indicating timing of HTx in patients with CW-TAH, as well as the potential for clinical deterioration following portable driver substitution. PMID:26497137

  3. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... who have symptomatic aortic stenosis of a severe nature. It's even been liberalized in some patient populations ... the heart. The aortic valve, because of its nature being in back of the heart, is not ...

  4. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... heart valve which is made out of pyrolitic carbon, basically metal and plastic. Again, blood flows through ... heart surgery here, we actually insufflate, or instill carbon dioxide gas into the field, which we think ...

  5. Results of beating heart mitral valve surgery via the trans-septal approach Resultados da abordagem transeptal para a valva mitral com coração batendo

    Directory of Open Access Journals (Sweden)

    Tomas A Salerno

    2009-03-01

    Full Text Available OBJECTIVE: Mitral valve surgery can be performed through the trans-atrial or the trans-septal approach. Although the trans-atrial is the preferred method, the trans-septal approach has also been used recently and has a particular value in beating-heart mitral valve surgery. Herein we report our experience with beating-heart mitral valve surgery via trans-septal approach, and discuss its advantages and pitfalls. METHODS: Between 2000 and 2007, 214 consecutive patients were operated upon utilizing beating heart technique for mitral valve surgery. The operation was performed via transseptal approach with the aorta unclamped, the heart beating, with normal electrocardiogram and in sinus rhythm. RESULTS: Mean age was 56.03 ± 13.93 years (range: 19-86 years; median: 56 years. There were 131 (61.2% males and 83 (38.8% females. Of the prostheses used, 108 (50.5% were biological, and 39 (18.2% were mechanical. Mitral repairs were performed in 67 (31.3% patients. Mean hospital stay was 17.4 ± 20.0 days (range: 3-135 days; median: 11 days. Intra-aortic balloon pump (IABP utilization was required in 12 (5.6% of 214 patients. One-month mortality was 7.4%, and re-operation for bleeding was needed in 15 (7% patients. CONCLUSIONS: Beating-heart mitral valve surgery is an option for myocardial protection in patients undergoing mitral valve surgery. This technique is facilitated by the trans-septal approach due to reduced aortic insufficiency and improved visualization of the mitral apparatus.OBJETIVO: A cirurgia da valva mitral pode ser feita via transatrial ou transeptal. Embora a transatrial seja a preferida, a via transeptal tem sido utilizada mais recentemente e tido um grande valor nas operações com o coração batendo. Mostramos a nossa experiência na cirurgia da valva mitral via transeptal com coração batendo e discutimos seus benefícios e problemas. MÉTODOS: Entre 2000 e 2007, 214 pacientes consecutivos foram operados com o coração batendo. A

  6. [Flowmetric assessment of coronary bypass grafts in the conditions of artificial circulation and on the beating heart].

    Science.gov (United States)

    Bazylev, V V; Nemchenko, E V; Karnakhin, V A; Pavlov, A A; Mikulyak, A I

    2016-01-01

    Advantages and shortcomings of aortocoronary bypass grafting on the beating heart and in the conditions of artificial circulation (AC) have long been discussed. The data on patency of bypass grafts in the remote period are indicative of comparable results of operations with and without AC or advantages of using AC. In order to determine benefits of each method it is necessary to reveal intraoperative predictors of bypass grafts occlusion in the remote period. We analyzed the results of ultrasound flowmetry of the blood flow through the left internal thoracic artery during bypass grafting of the anterior descending artery with the use of AC and on the beating heart. A retrospective study included a total of 352 patients subdivided into 2 groups: Group One was composed of 120 patients undergoing surgery in the conditions of AC and Group Two comprised 232 patients subjected to similar operations on the beating heart. Blood flow was measured with the help of flowmeter VeryQ MediStim® after termination of AC and inactivation of heparin by protamine, with systolic pressure of 100-110 mm Hg. There were no statistically significant differences between the groups by the diameter and degree of stenosis of the anterior descending artery, diameter of the left internal thoracic artery. The mean volumetric blood flow velocity (Qmean) along the shunts in Group One was higher (p=0.01). No statistically significant differences by the pulsatility index (PI) between the groups were revealed (p=0.2). A conclusion was drawn that coronary bypass grafting of the anterior descending artery by the left internal thoracic artery in the conditions of artificial circulation made it possible to achieve higher volumetric velocity of blood flow through the conduit as compared with operations on the beating heart, with similar resistance index. The immediate results of the operations with the use of the both techniques did not differ. PMID:27100540

  7. 4D optical coherence tomography of aortic valve dynamics in a murine mouse model ex vivo

    Science.gov (United States)

    Schnabel, Christian; Jannasch, Anett; Faak, Saskia; Waldow, Thomas; Koch, Edmund

    2015-07-01

    The heart and its mechanical components, especially the heart valves and leaflets, are under enormous strain during lifetime. Like all highly stressed materials, also these biological components undergo fatigue and signs of wear, which impinge upon cardiac output and in the end on health and living comfort of affected patients. Thereby pathophysiological changes of the aortic valve leading to calcific aortic valve stenosis (AVS) as most frequent heart valve disease in humans are of particular interest. The knowledge about changes of the dynamic behavior during the course of this disease and the possibility of early stage diagnosis could lead to the development of new treatment strategies and drug-based options of prevention or therapy. ApoE-/- mice as established model of AVS versus wildtype mice were introduced in an ex vivo artificially stimulated heart model. 4D optical coherence tomography (OCT) in combination with high-speed video microscopy were applied to characterize dynamic behavior of the murine aortic valve and to characterize dynamic properties during artificial stimulation. OCT and high-speed video microscopy with high spatial and temporal resolution represent promising tools for the investigation of dynamic behavior and their changes in calcific aortic stenosis disease models in mice.

  8. "And the Beat Goes Ona... Building Artificial Hearts in the Classroom.

    Science.gov (United States)

    Brock, David L.

    2000-01-01

    Among the many ideas and theories in anatomy and physiology, one particular topic provides all the potential benefits of learning about the human body: the circulatory system, specifically the heart. Describes a distinctive way to study circulation and the heart that allows students to explore the basic principles of vertebrate anatomy and…

  9. Testes in vitro e in vivo com o Coração Artificial Auxiliar (CAA: um novo modelo de coração artificial totalmente implantável e heterotópico In vitro and in vivo tests with the Auxiliary Total Artificial Heart (ATAH: a new device of a totally implantable and heterotopic artificial heart

    Directory of Open Access Journals (Sweden)

    Aron ANDRADE

    1999-04-01

    Full Text Available Um novo modelo de coração artificial está sendo desenvolvido e testado em nossos laboratórios, o Coração Artificial Auxiliar (CAA. Este dispositivo foi projetado com dimensões reduzidas para ser implantado em paralelo ao coração natural do paciente, dentro da cavidade torácica direita de forma heterotópica. Foram realizados testes in vitro, em um circuito simulador do sistema circulatório humano, para verificação do desempenho hidrodinâmico do CAA. Os resultados mostraram que o CAA pode fornecer um fluxo de até 5,8 L/min, com uma pré-carga de 20 mmHg e uma pós-carga de 100 mmHg. A freqüência de batimento do CAA e, consequentemente, o débito cardíaco são dependentes da pré-carga do ventrículo esquerdo, funcionamento semelhante ao coração natural (Lei de Frank Starling. Testes in vivo animal estão sendo realizados para avaliar os resultados obtidos com os testes in vitro e para verificar o comportamento do CAA em ambiente e condições fisiológicas difíceis de serem simuladas. Os testes in vivo estão sendo também importantes para o desenvolvimento de técnicas cirúrgicas e treinamento dos cirurgiões cardiovasculares envolvidos no projeto. Até o momento, dois estudos agudos in vivo foram realizados, com o CAA funcionando por 5h, implantado na cavidade torácica direta de carneiros adultos (50 ± 5 kg. Os resultados destes estudos in vivo demonstraram que o funcionamento do CAA é sincronizado ao coração natural, sendo possível estudar o comportamento do CAA quando, gradativamente, o coração natural teve sua contratilidade reduzida até sua parada total.A miniaturized artificial heart is being developed in the authors laboratories, the Auxiliary Total Artificial Heart (ATAH. This device is an electromechanically driven ATAH using a brushless direct current (DC motor fixed in a center aluminum piece. This pusher plate type ATAH is controlled based on Frank-Starling's law. The beating frequency is regulated

  10. A multi-objective approach to evolving artificial neural networks for coronary heart disease classification

    OpenAIRE

    Shenfield, Alex; Rostami, Shahin

    2015-01-01

    The optimisation of the accuracy of classifiers in pattern recognition is a complex problem that is often poorly understood. Whilst numerous techniques exist for the optimisation of weights in artificial neural networks (e.g. the Widrow-Hoff least mean squares algorithm and back propagation techniques), there do not exist any hard and fast rules for choosing the structure of an artificial neural network - in particular for choosing both the number of the hidden layers used in the network and ...

  11. A numerical analysis on the curved bileaflet Mechanical Heart Valve (MHV) : leaflet motion and blood flow in an elastic blood vessel

    International Nuclear Information System (INIS)

    In blood flow passing through the Mechanical Heart Valve (MHV) and elastic blood vessel, hemolysis and platelet activation causing thrombus formation can be seen owing to the shear stress in the blood. Also, fracture and deformation of leaflets can be observed depending on the shape and material properties of the leaflets which is opened and closed in a cycle. Hence, comprehensive study is needed on the hemodynamics which is associated with the motion of leaflet and elastic blood vessel in terms of fluid-structure interaction. In this paper, a numerical analysis has been performed for a three-dimensional pulsatile blood flow associated with the elastic blood vessel and curved bileaflet for multiple cycles in light of fluid-structure interaction. From this analysis fluttering phenomenon and rebound of the leaflet have been observed and recirculation and regurgitation have been found in the flow fields of the blood. Also, the pressure distribution and the radial displacement of the elastic blood vessel have been obtained. The motion of the leaflet and flow fields of the blood have shown similar tendency compared with the previous experiments carried out in other studies. The present study can contribute to the design methodology for the curved bileaflet mechanical heart valve. Furthermore, the proposed fluid-structure interaction method will be effectively used in various fields where the interaction between fluid flow and structure are involved

  12. Role of Pre-incision, Intravenous Prophylactic Amiodarone to Control Arrhythmias in Patients with Rheumatic Valvular Heart Disease undergoing Mitral Valve Replacement

    International Nuclear Information System (INIS)

    Objective: To evaluate the effect of intra-operative single intra venous dose of amiodarone on post operative cardiac arrhythmias in patients undergoing valvular heart surgery. Study Design: Randomized controlled trials. Place and Duration of surgery: This study was performed at Armed forces Institute of Cardiology Rawalpindi from Jan 01, 2011 to Dec 31, 2011. Patients and Methods: In this study 80 patients with rheumatic valvular heart disease and undergoing elective mitral valve replacement were randomly divided into two groups. Group I, n = 40 (Amiodarone group) was given single intravenous dose of amiodarone (5 mg/kg in 100 ml of saline over 30 min) before sternotomy incision. Group II, n = 40(control / placebo group) was given 100 ml of saline over 30 min. Result: In the amiodarone group, after removal of aortic cross clamp 75% patients had sinus rhythm compared to 47.5% in control group. p=0.045. Similarly 15% had AF, 5% JR and 5% VT/VF in amiodarone group in contrast to 32.5% with AF, 12.5% JR and 7.5% Vt/VF in control group. (p=0.045). Response to cardioversion was positive in 75% of the patients requiring shocks in amiodarone group as against 43.75% in the control group. (p=0.044). Conclusion: A single intravenous bolus dose of amiodarone is effective in decreasing the incidence of cardiac arrhythmias after mitral valve replacement in patients with rheumatic MVD. (author)

  13. [PULMONARY COMPLICATIONS IN CHILDREN, OPERATED ON FOR INBORN HEART FAILURES IN THE ARTIFICIAL BLOOD CIRCULATION ENVIRONMENT].

    Science.gov (United States)

    Moshkivska, L V; Nastenko, E A; Golovenko, O S; Lazoryshynets, V V

    2015-11-01

    The risk factors of pulmonary complications occurrence were analyzed in children, operated on for inborn heart failures in atrificial blood circulation environment. Pulmonary complications rate and the risk factors of their occurrence were analyzed. PMID:26939427

  14. CLASSIFICATION OF THE NORMAL AND ABNORMAL HEART SOUNDS VIA ARTIFICIAL NEURAL NETWORK

    OpenAIRE

    Güraksin, Gür Emre

    2009-01-01

    Listening with stethoscope is a preferential method that the doctors use in order to differentiate normal cardiac systems from the abnormal ones that come out. On the other hand, listening with stethoscope has a number of constraints. The interpretation of these various heart sounds depends on doctor's ability of hearing, experience and skill. Because of the problems that can be faced, listening process with stethoscope, that is auscultation, falls behind in the search of the heart abnormalit...

  15. Pediatric heart surgery - discharge

    Science.gov (United States)

    ... discharge; Heart valve surgery - children - discharge; Heart surgery - pediatric - discharge; Heart transplant - pediatric - discharge ... Keane JF, Lock JE, Fyler DC, eds. Nadas' Pediatric Cardiology . 2nd ed. St. Louis, MO; WB Saunders; ...

  16. What Causes Heart Murmurs?

    Science.gov (United States)

    ... and get carried to the heart can sometimes infect the inner surface of the heart, including the heart valves. This rare but sometimes life-threatening infection is called infective endocarditis (EN-do-kar-DI-tis), or IE. IE ...

  17. Incorporating an Exercise Detection, Grading, and Hormone Dosing Algorithm Into the Artificial Pancreas Using Accelerometry and Heart Rate.

    Science.gov (United States)

    Jacobs, Peter G; Resalat, Navid; El Youssef, Joseph; Reddy, Ravi; Branigan, Deborah; Preiser, Nicholas; Condon, John; Castle, Jessica

    2015-11-01

    In this article, we present several important contributions necessary for enabling an artificial endocrine pancreas (AP) system to better respond to exercise events. First, we show how exercise can be automatically detected using body-worn accelerometer and heart rate sensors. During a 22 hour overnight inpatient study, 13 subjects with type 1 diabetes wearing a Zephyr accelerometer and heart rate monitor underwent 45 minutes of mild aerobic treadmill exercise while controlling their glucose levels using sensor-augmented pump therapy. We used the accelerometer and heart rate as inputs into a validated regression model. Using this model, we were able to detect the exercise event with a sensitivity of 97.2% and a specificity of 99.5%. Second, from this same study, we show how patients' glucose declined during the exercise event and we present results from in silico modeling that demonstrate how including an exercise model in the glucoregulatory model improves the estimation of the drop in glucose during exercise. Last, we present an exercise dosing adjustment algorithm and describe parameter tuning and performance using an in silico glucoregulatory model during an exercise event. PMID:26438720

  18. Successful thrombolysis for prosthetic pulmonary valve obstruction.

    OpenAIRE

    Lopez, J. A.; Strickman, N E; Jin, B S; X. G. Li; Phan, B; Zeluff, B J; Wilansky, S

    1995-01-01

    Thrombosis is a serious complication of prosthetic heart valve operations. In recent years, systemic thrombolysis has emerged as a suitable alternative to surgery. Experience with thrombosis of pulmonary prosthetic valves is very limited. We report a case of successful administration of intravenous streptokinase for thrombosis of a St. Jude Medical prosthetic valve 3 weeks after pulmonary valve replacement.

  19. Evaluation of 17-mm St. Jude Medical Regent prosthetic aortic heart valves by rest and dobutamine stress echocardiography

    Directory of Open Access Journals (Sweden)

    Minardi Giovanni

    2006-09-01

    Full Text Available Abstract Background The prosthesis used for aortic valve replacement in patients with small aortic root can be too small in relation to body size, thus showing high transvalvular gradients at rest and/or under stress conditions. This study was carried out to evaluate rest and Dobutamine stress echocardiography (DSE hemodynamic response of 17-mm St. Jude Medical Regent (SJMR-17 mm in relatively aged patients at mean 24 months follow-up. Methods and results The study population consisted of 19 patients (2 men, 17 women, mean age 69.2 ± 7.3 years. All patients underwent rest Doppler echocardiography before and after surgery and basal and DSE at follow up (infused at rate of 5 micrg/Kg/min and increased by 5 microg/Kg/min at 5 min intervals up to 40 microg/Kg/min. The following parameters were evaluated at rest and/or under DSE: heart rate (HR, ejection fraction (EF, cardiac output (CO, peak and mean velocity and pressure gradients (MxV, MnV, MxPG, MnPG, effective orifice area (EOA, indexed EOA (EOAi, left ventricular mass (LVM, indexed LVM (LVMi, Velocity Time Integral at left ventricular outflow tract (VTI LVOT and transvalvular (Aortic VTI, Doppler velocity index (DVI. At rest MxPG and MnPG were 29.2 ± 7.1 and 16.6 ± 5.8mmHg, respectively; EOA and EOAi resulted 1.14 ± 0.3 cm2 and 0.76 ± 0.2 cm2/m2; DVI was normal (0.50 ± 0.1. At follow-up LVM and LVMi decreased significantly from pre-operative value of 258 ± 43g and 157.4 ± 27.7g/m2 to 191 ± 23.8g and 114.5 ± 10.6g/m2, respectively. DSE increased significantly HR, CO, EF, MxGP (up to 83.4 ± 2 1.9mmHg, MnPG (up to 43.2 ± 12.7mmHg. EOA, EOAi, DVI increased insignificantly (from baseline up to 1.2 ± 0.4 cm2, 0.75 ± 0.3cm2/m2 and 0.48 ± 0.1 respectively. Two patients developed significant intraventricular gradients. Conclusion These data show that SJMR 17-mm prostheses can be safely implanted in aortic position in relatively aged patients, offering a satisfactory hemodynamic

  20. A systematic method for using 3D echocardiography to evaluate tricuspid valve insufficiency in hypoplastic left heart syndrome

    Directory of Open Access Journals (Sweden)

    Christopher Robin Mart

    2014-01-01

    We have proposed a systematic method for evaluating and displaying the TV using 3DE which can provide significant insight into the mechanisms causing TVI in HLHS. This has the potential to improve both the surgical approach to repairing the valve and, ultimately, patient outcomes.

  1. [Modern mitral valve surgery].

    Science.gov (United States)

    Bothe, W; Beyersdorf, F

    2016-04-01

    At the beginning of the 20th century, Cutler and Levine performed the first successful surgical treatment of a stenotic mitral valve, which was the only treatable heart valve defect at that time. Mitral valve surgery has evolved significantly since then. The introduction of the heart-lung machine in 1954 not only reduced the surgical risk, but also allowed the treatment of different mitral valve pathologies. Nowadays, mitral valve insufficiency has become the most common underlying pathomechanism of mitral valve disease and can be classified into primary and secondary mitral insufficiency. Primary mitral valve insufficiency is mainly caused by alterations of the valve (leaflets and primary order chords) itself, whereas left ventricular dilatation leading to papillary muscle displacement and leaflet tethering via second order chords is the main underlying pathomechanism for secondary mitral valve regurgitation. Valve reconstruction using the "loop technique" plus annuloplasty is the surgical strategy of choice and normalizes life expectancy in patients with primary mitral regurgitation. In patients with secondary mitral regurgitation, implanting an annuloplasty is not superior to valve replacement and results in high rates of valve re-insufficiency (up to 30 % after 3 months) due to ongoing ventricular dilatation. In order to improve repair results in these patients, we add a novel subvalvular technique (ring-noose-string) to the annuloplasty that aims to prevent ongoing ventricular remodeling and re-insufficiency. In modern mitral surgery, a right lateral thoracotomy is the approach of choice with excellent repair and cosmetic results. PMID:26907868

  2. Pediatric heart surgery

    Science.gov (United States)

    Heart surgery - pediatric; Heart surgery for children; Acquired heart disease; Heart valve surgery - children ... There are many kinds of heart defects. Some are minor, and others are more serious. Defects can occur inside the heart or in the large blood vessels ...

  3. Artificial heart development program. Volume II. System support. Phase III summary report. Period covered: July 1, 1973--September 30, 1977

    International Nuclear Information System (INIS)

    Appendix A covers major activities of the Artificial Heart Development program that supported the design, fabrication, and test of the system demonstration units. Section A.1.0 provides a listing beyond that of the body of the report on the components needed for an implantation. It also presents glove box sterilization calibration results and results of an extensive mock circulation calibration. Section A.2.0 provides detail procedures for assembly, preparing for use, and the use of the system and major components. Section A.3.0 covers the component research and development activities undertaken to improve components of the existing system units and to prepare for a future prototype system. Section A.4.0 provides a listing of the top assembly drawings of the major systems variations fabricated and tested

  4. Artificial heart development program. Volume II. System support. Phase III summary report. Period covered: July 1, 1973--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Appendix A covers major activities of the Artificial Heart Development program that supported the design, fabrication, and test of the system demonstration units. Section A.1.0 provides a listing beyond that of the body of the report on the components needed for an implantation. It also presents glove box sterilization calibration results and results of an extensive mock circulation calibration. Section A.2.0 provides detail procedures for assembly, preparing for use, and the use of the system and major components. Section A.3.0 covers the component research and development activities undertaken to improve components of the existing system units and to prepare for a future prototype system. Section A.4.0 provides a listing of the top assembly drawings of the major systems variations fabricated and tested.

  5. Artificial heart development program. Volume II. System support. Phase III summary report, July 1, 1973--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Volume 2 covers major activities of the Artificial Heart Development program that supported the design, fabrication, and test of the system demonstration units. Section A.1.0 provides a listing beyond that of the body of the report on the components needed for an implantation. It also presents glove box sterilization calibration results and results of an extensive mock circulation calibration. Section A.2.0 provides detailed procedures for assembly, preparing for use, and the use of the system and major components. Section A.3.0 covers the component research and development activities undertaken to improve components of the existing system units and to prepare for a future prototype system. Section A.4.0 provides a listing of the top assembly drawings of the major systems variations fabricated and tested.

  6. Biological effects of implanted nuclear energy sources for artificial heart devices. Progress report, September 1, 1975--August 31, 1976

    International Nuclear Information System (INIS)

    A total of sixty dogs were implanted with radioisotope-powered artificial heart systems producing radiation fluxes similar to that of plutonium-238, but having no associated heat, at levels of from one to seventy times the radiation flux expected from a 30-watt plutonium-238 source. Results from studies lasting up to 6 years after implantation indicate that these animals, and by inference human beings, may be able to tolerate the radiation flux from 30-watt 238Pu power sources. Results of heat dissipation studies in calves indicate that it may be possible to induce a vascularized connective tissue capsule sufficient to dissipate 30 watts of additional heat from a surface area of approximately 500 cm sq., allowing a heat flux of 0.06 watts per cm sq

  7. Artificial heart development program. Volume II. System support. Phase III summary report, July 1, 1973--September 30, 1977

    International Nuclear Information System (INIS)

    Volume 2 covers major activities of the Artificial Heart Development program that supported the design, fabrication, and test of the system demonstration units. Section A.1.0 provides a listing beyond that of the body of the report on the components needed for an implantation. It also presents glove box sterilization calibration results and results of an extensive mock circulation calibration. Section A.2.0 provides detailed procedures for assembly, preparing for use, and the use of the system and major components. Section A.3.0 covers the component research and development activities undertaken to improve components of the existing system units and to prepare for a future prototype system. Section A.4.0 provides a listing of the top assembly drawings of the major systems variations fabricated and tested

  8. [Preparation of Ti-O Film Deposited on the Surface of a New Type of Artificial Mechanical Heart Valve].

    Science.gov (United States)

    Zhou, Feng; Cui, Yuanyuan; Wu, Liangliang; Sun, Hong; Huang, Nan

    2015-04-01

    The rutile structure titanium oxide (Ti-O) film was prepared on the pure titanium material TA2 (99.999%) surface by the magnetic filter high vacuum arc deposition sputtering source. The method can not only maintain the material mechanical properties, but also improve the surface properties for better biocompatibility to accommodate the physiological environment. The preparation process of the Ti-O film was as follows. Firstly, argon ions sputtered to the TA2 substrate surface to remove the excess impurities. Secondly, a metal ion source generated Ti ions and oxygen ions by the RF discharge. Meanwhile a certain negative bias was imposed on the sample. There a certain composition of Ti-O film was obtained under a certain pressure of oxygen in the vacuum chamber. Finally, X-ray diffraction was used to research the structure and composition of the film. The results showed that the Ti-O film of the rutile crystal structure was formed under the 0.18 Pa oxygen partial pressure. A Nano scratch experiment was used to test the coating adhesion property, which demonstrated that the film was stable and durable. The contact angle experiment and the platelet clotting experiment proved that the modified surface method had improved platelet adhesion performance, and, therefore, the material possessed better biocompatibility. On the whole, the evaluations proved the modified material had excellent performance. PMID:26211266

  9. Ovalis TAH: development and in vitro testing of a new electromechanical energy converter for a total artificial heart.

    Science.gov (United States)

    Sauer, I M; Frank, J; Spiegelberg, A; Bücherl, E S

    2000-01-01

    A new electromechanical energy converting system has been developed to yield an efficient and durable orthotopic total artificial heart (TAH). The energy converter we developed transforms the unidirectional rotational motion of the motor into a longitudinal forward-reverse movement of an internal geared oval, linked directly to pusher plates on both sides. To ensure a permanent positive connection between the drive gear and the internally geared wheel, a ball bearing runs inside an oval shaped guide track. Motor, gear unit, and conical pusher plates are seated between alternately ejecting and filling ventricles. The unidirectional motion of the brushless DC motor affords easier motor control, reduces energy demand, and ensures longer life of the motor when compared with a bidirectional motion system. In vitro testing has been performed on a mock circulation loop. The overall system efficiency of the TAH Ovalis was 27-39% (mean, 36%) for the pump output range of 2-7 L/min. The maximum output of 7 L/min can be obtained with a pump rate of 130 min(-1) and an afterload pressure of 140 mm Hg. For an average sized human with a mean cardiac output of 6 L/min at a mean aortic pressure of 120 mm Hg, 5 watts of input power would be required. The size of the prototype is 560 cm3, the weight is 950 g. Our first in vitro studies demonstrated the excellent efficiency and pump performance of this new electromechanical energy converter. The results prove the feasibility of this new concept's use as an energy converter for a total artificial heart. PMID:11110274

  10. Evaluation of shrinkage temperature of bovine pericardium tissue for bioprosthetic heart valve application by differential scanning calorimetry and freeze-drying microscopy

    Directory of Open Access Journals (Sweden)

    Virgilio Tattini Jr

    2007-03-01

    Full Text Available Bovine pericardium bioprosthesis has become a commonly accepted device for heart valve replacement. Present practice relies on the measurement of shrinkage temperature, observed as a dramatic shortening of tissue length. Several reports in the last decade have utilized differential scanning calorimetry (DSC as an alternative method to determine the shrinkage temperature, which is accompanied by the absorption of heat, giving rise to an endothermic peak over the shrinkage temperature range of biological tissues. Usually, freeze-drying microscope is used to determine collapse temperature during the lyophilization of solutions. On this experiment we used this technique to study the shrinkage event. The aim of this work was to compare the results of shrinkage temperature obtained by DSC with the results obtained by freeze-drying microscopy. The results showed that both techniques provided excellent sensitivity and reproducibility, and gave information on the thermal shrinkage transition via the thermodynamical parameters inherent of each method.

  11. Editorial to: Baseline MDCT findings after prosthetic heart valve implantation provide important complementary information to echocardiography for follow-up purposes by Sucha et al

    Energy Technology Data Exchange (ETDEWEB)

    Peeters, F.E.C.M. [Maastricht University Medical Center, Department of Cardiology, Maastricht (Netherlands); Kietselaer, B.L.J.H. [Maastricht University Medical Center, Department of Cardiology, Maastricht (Netherlands); Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands)

    2016-04-15

    Over the last years a growing number of prosthetic heart valve (PHV) implantation procedures have been performed in sequence with the aging of the population and improving surgical techniques. Currently, echocardiography is the most important tool in the follow-up and evaluation of complications associated with the PHV (pannus, thrombus, endocarditis). However, echocardiographic examination of PHV associated disease may be hampered by poor acoustic window or scatter artefacts caused by the PHV. PHV related disease such as endocarditis is related with a poor prognosis, especially when complications such as periannular abscess formation occurs. Early treatment of PHV associated disease improves prognosis. Therefore, an unmet clinical need for early detection of complications exists. In the evaluation of PHV (dys)function, multidetector-row computed tomography (MDCT) has shown to be of additive value. A necessity for MDCT to be implemented in daily practice is to be able to distinguish between normal and pathological features. (orig.)

  12. Editorial to: Baseline MDCT findings after prosthetic heart valve implantation provide important complementary information to echocardiography for follow-up purposes by Sucha et al

    International Nuclear Information System (INIS)

    Over the last years a growing number of prosthetic heart valve (PHV) implantation procedures have been performed in sequence with the aging of the population and improving surgical techniques. Currently, echocardiography is the most important tool in the follow-up and evaluation of complications associated with the PHV (pannus, thrombus, endocarditis). However, echocardiographic examination of PHV associated disease may be hampered by poor acoustic window or scatter artefacts caused by the PHV. PHV related disease such as endocarditis is related with a poor prognosis, especially when complications such as periannular abscess formation occurs. Early treatment of PHV associated disease improves prognosis. Therefore, an unmet clinical need for early detection of complications exists. In the evaluation of PHV (dys)function, multidetector-row computed tomography (MDCT) has shown to be of additive value. A necessity for MDCT to be implemented in daily practice is to be able to distinguish between normal and pathological features. (orig.)

  13. Evaluation of 17-mm St. Jude Medical Regent prosthetic aortic heart valves by rest and dobutamine stress echocardiography

    OpenAIRE

    Minardi Giovanni; Manzara Carla; Creazzo Vittorio; Maselli Daniele; Casali Giovanni; Pulignano Giovanni; Musumeci Francesco

    2006-01-01

    Abstract Background The prosthesis used for aortic valve replacement in patients with small aortic root can be too small in relation to body size, thus showing high transvalvular gradients at rest and/or under stress conditions. This study was carried out to evaluate rest and Dobutamine stress echocardiography (DSE) hemodynamic response of 17-mm St. Jude Medical Regent (SJMR-17 mm) in relatively aged patients at mean 24 months follow-up. Methods and results The study population consisted of 1...

  14. Achievement report for fiscal 1998. Totally implantable artificial heart system; 1998 nendo seika hokokusho. Tainai umekomigata jinko shinzo system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    Development has been made on element technologies for a totally implantable artificial hear system. Performance improvement in a regenerative pump has enhanced high-speed followability of the system, having achieved the maximum ejection flow rate of 11.8 liters per minute at pulse of 120 bpm. A system endurance test has elapsed 551 days and is still continuing. Based on the result of evaluating the basic functions of the first prototype of a magnetically suspended pump, trial production was performed on an improved magnetically suspended pump whose volume of implantation in the left and right pumps was reduced to about 320 cc. The energy transmission system achieved transmission efficiency of 82% or higher, and temperature rise of three degrees C. In the information transmission system, laser diodes were used to make information transmission possible at 9600 bytes per second. The implanted secondary battery is a lithium ion battery, which was confirmed of operating the artificial hear for longer than 30 minutes. With regard to the structural and coating materials, no thrombus formation was observed in an animal experiment for the magnetically suspended continuous pump whose liquid contacting parts made of polycarbonate are heparinized. Titanium was used in the liquid contacting parts and the texture contacting parts of the left heart magnetically suspended pump. (NEDO)

  15. Materials testing and requirement for the ERDA nuclear-powered artificial heart. Technical progress report, July 15, 1975--May 30, 1976

    International Nuclear Information System (INIS)

    The two materials currently being used for the artificial heart fabrication are BIOMER and AVCOTHANE. BIOMER is a polyether urethane polymer. AVCOTHANE is a proprietary polyurethane/polydimethylsiloxane polymer blend. Research progress on the chemical degradation, mechanical strength, and blood compatibility is reported

  16. Materials testing and requirement for the ERDA nuclear-powered artificial heart. Technical progress report, July 15, 1975--May 30, 1976. [BIOMER and AVCOTHANE

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, J. D.; Hufferd, W. L.; Lyman, D. J.

    1976-01-01

    The two materials currently being used for the artificial heart fabrication are BIOMER and AVCOTHANE. BIOMER is a polyether urethane polymer. AVCOTHANE is a proprietary polyurethane/polydimethylsiloxane polymer blend. Research progress on the chemical degradation, mechanical strength, and blood compatibility is reported. (TFD)

  17. Cyclic fatigue and fracture in pyrolytic carbon-coated graphite mechanical heart-valve prostheses: role of small cracks in life prediction.

    Science.gov (United States)

    Dauskardt, R H; Ritchie, R O; Takemoto, J K; Brendzel, A M

    1994-07-01

    A fracture-mechanics based study has performed to characterize the fracture toughness and rates of cyclic fatigue-crack growth of incipient flaws in prosthetic heart-valve components made of pyrolytic carbon-coated graphite. Such data are required to predict the safe structural lifetime of mechanical heart-valve prostheses using damage-tolerant analysis. Unlike previous studies where fatigue-crack propagation data were obtained using through-thickness, long cracks (approximately 2-20 mm long), growing in conventional (e.g., compact-tension) samples, experiments were performed on physically small cracks (approximately 100-600 microns long), initiated on the surface of the pyrolytic-carbon coating to simulate reality. Small-crack toughness results were found to agree closely with those measured conventionally with long cracks. However, similar to well-known observations in metal fatigue, it was found that based on the usual computations of the applied (far-field) driving force in terms of the maximum stress intensity, Kmax, small fatigue cracks grew at rates that exceeded those of long cracks at the same applied stress intensity, and displayed a negative dependency on Kmax; moreover, they grew at applied stress intensities less than the fatigue threshold value, below which long cracks are presumed dormant. To resolve this apparent discrepancy, it is shown that long and small crack results can be normalized, provided growth rates are characterized in terms of the total (near-tip) stress intensity (incorporating, for example, the effect of residual stress); with this achieved, in principle, either form of data can be used for life prediction of implant devices. Inspection of the long and small crack results reveals extensive scatter inherent in both forms of growth-rate data for the pyrolytic-carbon material. PMID:8083247

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

    Science.gov (United States)

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

    2016-01-01

    The Medtronic ATS Open Pivot mechanical valve has been successfully used in heart valve surgery for more than two decades. We present the case of a patient who, 19 years following a tricuspid valve replacement with an ATS prosthesis as part of a triple valve operation following infective endocarditis, developed severe tricuspid regurgitation due to pannus formation. PMID:27355145

  19. Aortic valve replacement

    DEFF Research Database (Denmark)

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

    2008-01-01

    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European countr...... southern European countries. Imbalances in the prevalence of rheumatic heart disease, health resource availability and variations in surgical practice throughout Europe might be possible etiological causes....

  20. 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.)

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

    International Nuclear Information System (INIS)

    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.)

  2. Door valve

    International Nuclear Information System (INIS)

    Object: To reliably block leakage of inner fluid in a door valve by providing a bellows mechanism in a portion where a valve rod penetrates an oil hydraulic cylinder and by sealing opposite side valve seats of the valve body with an oil hydraulic type seal mechanism. Structure: A door valve comprising a valve body movably provided within a valve casing, an oil hydraulic mechanism driving a valve rod directly connected to the valve body, a bellows mechanism provided on a portion where a valve rod penetrates the cylinder of the oil hydraulic mechanism and an oil hydraulic seal mechanism provided on the inner side of an inlet of the valve casing opposing a valve seat of the valve body, thereby isolating such components as the reactor container, casker, relay container and fuel storage tank at the time of replacement of fuel and reliably preventing leakage of liquid metal vapor containing radioactive material. (Kamimura, M.)

  3. Intelligent postoperative morbidity prediction of heart disease using artificial intelligence techniques.

    Science.gov (United States)

    Hsieh, Nan-Chen; Hung, Lun-Ping; Shih, Chun-Che; Keh, Huan-Chao; Chan, Chien-Hui

    2012-06-01

    Endovascular aneurysm repair (EVAR) is an advanced minimally invasive surgical technology that is helpful for reducing patients' recovery time, postoperative morbidity and mortality. This study proposes an ensemble model to predict postoperative morbidity after EVAR. The ensemble model was developed using a training set of consecutive patients who underwent EVAR between 2000 and 2009. All data required for prediction modeling, including patient demographics, preoperative, co-morbidities, and complication as outcome variables, was collected prospectively and entered into a clinical database. A discretization approach was used to categorize numerical values into informative feature space. Then, the Bayesian network (BN), artificial neural network (ANN), and support vector machine (SVM) were adopted as base models, and stacking combined multiple models. The research outcomes consisted of an ensemble model to predict postoperative morbidity after EVAR, the occurrence of postoperative complications prospectively recorded, and the causal effect knowledge by BNs with Markov blanket concept. PMID:21184153

  4. GIANT PROSTHETIC VALVE THROMBUS

    Directory of Open Access Journals (Sweden)

    Prashanth Kumar

    2015-04-01

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

  5. A new transcutaneous bidirectional communication for monitoring implanted artificial heart using the human body as a conductive medium.

    Science.gov (United States)

    Okamoto, Eiji; Kato, Yoshikuni; Seino, Kazuyuki; Miura, Hidekazu; Shiraishi, Yasuyuki; Yambe, Tomoyuki; Mitamura, Yoshinori

    2012-10-01

    A transcutaneous communication system (TCS) is a key technology for monitoring and controlling artificial hearts and other artificial organs in the body. In this study, we developed a new TCS that uses the human body as a conductive medium. Direct data exchange provides a higher level of communication security compared to that of wireless methods without physical constraints such as an external wire. The external and internal units of the new TCS each consist mainly of a data transmitter and a data receiver. The data transmitter has an amplitude shift keying (ASK) modulator (carrier frequencies: 4 and 10 MHz) and an electrode. The ASK-modulated data current is led into the body through the electrode, and it flows back to the energy source through the body, the data receiver, and the earth ground that includes all conductors and dielectrics in the environment that are in close proximity to the patient. Performance of the TCS was evaluated by a communication test on the surface of the human body and in an animal experiment using a goat. The TCS was able to transmit data concurrently for 4 weeks between everywhere on the surface of the body and everywhere inside the body under full-duplex communication at a transmission rate of 115 kbps. The power consumption of each TCS unit was 125 mW with an ASK-modulated current of 7 mA (root-mean-square). While further study is required to secure its safety, the newly developed TCS has promise to be a next-generation transcutaneous communication device. PMID:22812488

  6. Heart failure - surgeries and devices

    Science.gov (United States)

    ... right ventricular assist devices (RVAD) or a total artificial hearts. They are considered for use if you have ... be on a heart-lung bypass machine. Total artificial hearts are being developed, but are not yet in ...

  7. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... a rare problem where the patient's own immune system will attack cardiac valve structures, causing them to ... it be heart, lung et cetera, the immune system recognizes those living issues as not being from ...

  8. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... other cardiovascular diseases including heart attack and increased risk of cardiovascular death. John, is there anything you ... with time. This highlights the mortality or the risk of death associated with aortic valve replacement and ...

  9. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... Dr. Jim Winkley, who's a cardiac anesthesiologist that works here with us. Before we begin, viewers need ... the valve itself has narrowed, that puts more work on the heart when a patient's at rest. ...

  10. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... valve is made of three pieces of thin tissue that opens freely when the heart contracts. On ... a lot of calcium and thickening of that tissue and does not open easily or appropriately. This ...

  11. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... North Carolina. My name is John Streitman and I'm a cardiothoracic surgeon here at the Heart ... the corrective surgery of aortic valve replacement. If I have aortic stenosis, are there any activities that ...

  12. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... patient's heart should have to undergo. Once again, serial evaluations, as with any chronic disease process, are ... to prevent such a problem. Is there a higher risk in someone with a biological valve for ...

  13. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... thank you, Jim. This is obviously just a model of the heart just to give some perspective ... the aorta at this point. 9 Earlier this month Robin Williams had his aortic valve replaced and ...

  14. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... when it progresses to stenosis, by either an increase in velocity of blood through the valve or ... in a normal patient, exercise and increased activity increases your heart rate and blood pressure, which then ...

  15. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... able to look at the aortic valve very well. In fact, transesophageal echocardiography is the best modality ... use to help evaluate both cardiac function as well as anatomy in patients who need heart surgery. ...

  16. Analysis of current density and specific absorption rate in biological tissue surrounding transcutaneous transformer for an artificial heart.

    Science.gov (United States)

    Shiba, Kenji; Nukaya, Masayuki; Tsuji, Toshio; Koshiji, Kohji

    2008-01-01

    This paper reports on the current density and specific absorption rate (SAR) analysis of biological tissue surrounding an air-core transcutaneous transformer for an artificial heart. The electromagnetic field in the biological tissue is analyzed by the transmission line modeling method, and the current density and SAR as a function of frequency, output voltage, output power, and coil dimension are calculated. The biological tissue of the model has three layers including the skin, fat, and muscle. The results of simulation analysis show SARs to be very small at any given transmission conditions, about 2-14 mW/kg, compared to the basic restrictions of the International Commission on nonionizing radiation protection (ICNIRP; 2 W/kg), while the current density divided by the ICNIRP's basic restrictions gets smaller as the frequency rises and the output voltage falls. It is possible to transfer energy below the ICNIRP's basic restrictions when the frequency is over 250 kHz and the output voltage is under 24 V. Also, the parts of the biological tissue that maximized the current density differ by frequencies; in the low frequency is muscle and in the high frequency is skin. The boundary is in the vicinity of the frequency 600-1000 kHz. PMID:18232363

  17. Artificial heart development program phase III summary report, July 1, 1973--September 30, 1977. Volume I. System development

    International Nuclear Information System (INIS)

    Efforts and results in the development of the power system portions of a calf-implantable model of nuclear-powered artificial heart are discussed. The primary objective in developing the implantable model was to solve the packaging problems for total system implantation. The power systems portion is physically that portion of the implantable model between the 238Pu heat sources and the blood pump ventricles. The 238Pu heat sources and blood pump ventricles were provided as Government Furnished Equipment as developed and fabricated by other contractors. The work performed had two parallel themes. The first of these was the development of an integrated implantable model for bench and animal experiments plus design effort on a more advanced model. The second was research and development on components of the system done in conjunction with the development of the implantable model and to provide technology for incorporation into advanced models plus support to implantations, at the University of Utah, of the systems blood pumping elements when driven by electric motor. The efforts and results of implantable model development are covered, mainly, in the text of the report. The research and development efforts and results are reported, primarily, in the appendices

  18. Biological effects of implanted nuclear energy sources for artificial heart devices. Progress report, September 1, 1974--August 31, 1975

    International Nuclear Information System (INIS)

    Results are reported from a study of the biological effects of radiation from mock plutonium power sources in dogs and a study of the feasibility of a tissue heat sink for waste heat from such sources in calves. It is also designed to evaluate effects of heat and radiation from plutonium sources in calves. The work is part of a program to evaluate the use of plutonium as a power source for an artificial heart device. A total of 60 dogs have been implanted with mock plutonium sources (producing a similar radiation flux as plutonium but having no associated heat) at levels of from 1 to 70 times the expected radiation flux from a 30 watt plutonium source. Results up to 4.5 years after implantation indicate that mammals may be able to tolerate the radiation flux from such sources. Results in calves indicate that 30 watts of additional endogenous heat can be dissipated to a connective tissue covered heat exchanger with a surface area of 494 cm2 providing a heat flux of 0.06 watts/cm2. (U.S.)

  19. Steady state hemodynamic and energetic characterization of the Penn State/3M Health Care Total Artificial Heart.

    Science.gov (United States)

    Weiss, W J; Rosenberg, G; Snyder, A J; Pierce, W S; Pae, W E; Kuroda, H; Rawhouser, M A; Felder, G; Reibson, J D; Cleary, T J; Ford, S K; Marlotte, J A; Nazarian, R A; Hicks, D L

    1999-01-01

    Total Artificial Heart (TAH) development at Penn State University and 3M Health Care has progressed from design improvements and manufacturing documentation to in vitro and in vivo testing to characterize the system's hemodynamic response and energetic performance. The TAH system is completely implantable and intended for use as an alternative to transplantation. It includes a dual pusher plate pump and rollerscrew actuator, welded electronics and battery assembly, transcutaneous energy transmission system, telemetry, and a compliance chamber. In vitro testing was conducted on a Penn State mock circulatory loop with glycerol/water solution at body temperature. Tests were performed to characterize the preload and afterload response, left atrial pressure control, and power consumption. A sensitive preload response was demonstrated with left atrial pressure safely maintained at less than 15 mm Hg for flow rates up to 7.5 L/min. Variations in aortic pressure and pulmonary vascular resistance were found to have minimal effects on the preload sensitivity and left atrial pressure control. In vivo testing of the completely implanted system in its final configuration was carried out in two acute studies using implanted temperature sensors mounted on the electronics, motor, and energy transmission coil in contact with adjacent tissue. The mean temperature at the device-tissue interface was less than 4 degrees C above core temperature. PMID:10360721

  20. Who Needs Heart Surgery?

    Science.gov (United States)

    ... find problems with the heart's function and valves. Cardiac Magnetic Resonance Imaging Magnetic resonance imaging (MRI) is a safe, noninvasive ... to create pictures of your organs and tissues. Cardiac MRI creates images of your heart as it is ...

  1. Heart-Health Screenings

    Science.gov (United States)

    ... Attack • Heart Failure (HF) • Heart Valve Problems and Disease • High Blood Pressure (HBP) • Metabolic Syndrome • Pericarditis • Peripheral Artery Disease (PAD) • Stroke • Venous Thromboembolism (VTE) • Consumer ...

  2. How the Heart Works

    Science.gov (United States)

    ... Your heart is at the center of your circulatory system. This system consists of a network of blood ... the walls contract, blood is pumped into your circulatory system. Inlet and outlet valves in your heart chambers ...

  3. Application of a PExSim for modeling a POLVAD artificial heart and the human circulatory system with left ventricle assistance

    Science.gov (United States)

    Siewnicka, Alicja; Fajdek, Bartlomiej; Janiszowski, Krzysztof

    2010-01-01

    This paper presents a model of the human circulatory system with the possible addition of a parallel assist device, which was developed for the purpose of artificial heart monitoring. Information about an identification experiment of an extracorporeal ventricle assist device POLVAD is included. The modelling methods applied and the corresponding functional blocks in a PExSim package are presented. The results of the simulation for physiological conditions, left ventricle failure and pathological conditions with parallel assistance are included.

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

    Directory of Open Access Journals (Sweden)

    Harish Ramakrishna

    2015-01-01

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

  5. BIOCHEMICAL AND MOLECULAR CHARACTERISTICS OF LISTERIA MONOCYTOGENES ISOLATES FROM A PROSTHETIC MITRAL HEART VALVE-BEARING PATIENT´S BLOOD CULTURES

    Directory of Open Access Journals (Sweden)

    Nilma Cintra Lea

    2013-09-01

    Full Text Available Background: In Brazil, listeriosis is not a notifiable disease; thus, the incidence of Brazilian cases remains unknown. Listeria monocytogenes is not always included in automated systems, and its detection depends on the high skill level of microbiology laboratory professionals. This paper describes the characteristics of L. monocytogenes isolates fortuitously obtained from an endocarditis case in Recife, PE, Brazil. Methods: Six bacterial isolates obtained from six blood cultures from a 28-year-old male bearing a prosthetic mitral heart valve were analyzed by PCR using primers specific of L. monocytogenes to confirm a presumptive identification, determine the serotype and presence of the virulence genes (inlA, inlB, inlC, inlJ, hly, plcA, actA, prfA in an attempt to determine the Listeria genotype by PCR-ribotyping. Results: The samples were identified as L. monocytogenes 4b. All investigated virulence genes were amplified by PCR, and the identity of the amplified segments was confirmed by sequencing. A deletion of 105 base pairs was detected in the actA gene. All of the samples generated the same PCR-ribotype pattern, clustered into a single ribotype, and were considered a single strain. Conclusion: L. monocytogenes infection should be considered in endocarditis differential diagnoses, especially among high-risk groups, due to its high pathogenicity and the environmental ubiquity.

  6. Indentation hardness: A simple test that correlates with the dissipated-energy predictor for fatigue-life in bovine pericardium membranes for bioprosthetic heart valves.

    Science.gov (United States)

    Tobaruela, Almudena; Rojo, Francisco Javier; García Paez, José María; Bourges, Jean Yves; Herrero, Eduardo Jorge; Millán, Isabel; Alvarez, Lourdes; Cordon, Ángeles; Guinea, Gustavo V

    2016-08-01

    The aim of this study was to evaluate the variation of hardness with fatigue in calf pericardium, a biomaterial commonly used in bioprosthetic heart valves, and its relationship with the energy dissipated during the first fatigue cycle that has been shown to be a predictor of fatigue-life (García Páez et al., 2006, 2007; Rojo et al., 2010). Fatigue tests were performed in vitro on 24 pericardium specimens cut in a root-to-apex direction. The specimens were subjected to a maximum stress of 1MPa in blocks of 10, 25, 50, 100, 250, 500, 1000 and 1500 cycles. By means of a modified Shore A hardness test procedure, the hardness of the specimen was measured before and after fatigue tests. Results showed a significant correlation of such hardness with fatigue performance and with the energy dissipated in the first cycle of fatigue, a predictor of pericardium durability. The study showed indentation hardness as a simple and reliable indicator of mechanical performance, one which could be easily implemented in improving tissue selection. PMID:26849027

  7. Biochemical and molecular characteristics of Listeria monocytogenes isolates from a prosthetic mitral heart valve-bearing patient´s blood cultures

    Directory of Open Access Journals (Sweden)

    Nilma Cintra Leal

    2013-09-01

    Full Text Available Background: In Brazil, listeriosis is not a notifiable disease; thus, the incidence of Brazilian cases remains unknown. Listeria monocytogenes is not always included in automated systems, and its detection depends on the high skill level of microbiology laboratory professionals. This paper describes the characteristics of L. monocytogenes isolates fortuitously obtained from an endocarditis case in Recife, PE, Brazil. Methods: Six bacterial isolates obtained from six blood cultures from a 28-year-old male bearing a prosthetic mitral heart valve were analyzed by PCR using primers specific of L. monocytogenes to confirm a presumptive identification, determine the serotype and presence of the virulence genes (inlA, inlB, inlC, inlJ, hly, plcA, actA, prfA in an attempt to determine the Listeria genotype by PCR-ribotyping. Results: The samples were identified as L. monocytogenes 4b. All investigated virulence genes were amplified by PCR, and the identity of the amplified segments was confirmed by sequencing. A deletion of 105 base pairs was detected in the actA gene. All of the samples generated the same PCR-ribotype pattern, clustered into a single ribotype, and were considered a single strain. Conclusion: L. monocytogenes infection should be considered in endocarditis differential diagnoses, especially among high-risk groups, due to its high pathogenicity and the environmental ubiquity.

  8. Mitral valve prolapse - report of 3 cases

    International Nuclear Information System (INIS)

    Prolapse of mitral valve is characterized by its unique auscultatory, echocardiographic and angiographic findings and may be associated with various disease entities such as congenital heart disease, coronary heart disease and Marfan's syndrome etc. Authors report recent experience of 3 cases of prolapsed mitral valve, 2 cases associated with A.S.D. and 1 case with Marfan's syndrome.

  9. In vivo performance evaluation of a transcutaneous energy and information transmission system for the total artificial heart.

    Science.gov (United States)

    Ahn, J M; Kang, D W; Kim, H C; Min, B G

    1993-01-01

    As part of an electromechanical total artificial heart (TAH) program, an integrated transcutaneous energy and information transmission (TEIT) system has been developed. In vivo performance of the developed system was evaluated through a simplified animal model without implant of a TAH. The design features include the small size of the implanted part, and dual coil structure of the external part. In the transcutaneous energy transmission (TET) system based on magnetic induction, the external primary and implanted secondary coils have the shape of a truncated cone, 7.0 and 3.8 cm in diameter, and 23 and 12 turns of Litz wire, respectively. The external coil is driven by a 350 to 410 kHz tuned class E amplifier that has a minimum switching loss of power transistor. In vitro test results using 1 cm thick dog's skin showed a flat total efficiency (DC to DC) of 75% for 20 to 30 W of delivered mean power. In order to achieve bidirectional communication between implanted and external components, a small circuit board containing four light emitting diodes and a photodiode was incorporated in each TET coil facing each other across the skin. Unmodulated optical pulse transmitted digital data (9600 baud, RS-232 protocol) in error free condition through an up to 15 mm thick dog's skin patch accommodated 18 degrees of misalignment. Three subacute in vivo studies were conducted in dogs to evaluate performance of the developed system. The secondary set was implanted in the mild flank region of the dog, and the output was percutaneously connected to the control system to drive the external TAH on the mock circulatory system.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8268530

  10. Reinforced chitosan-based heart valve scaffold and utility of bone marrow-derived mesenchymal stem cells for cardiovascular tissue engineering

    Science.gov (United States)

    Albanna, Mohammad Zaki

    Recent research has demonstrated a strong correlation between the differentiation profile of mesenchymal stem cells (MSCs) and scaffold stiffness. Chitosan is being widely studied for tissue engineering applications due to its biocompatibility and biodegradability. However, its use in load-bearing applications is limited due to moderate to low mechanical properties. In this study, we investigated the effectiveness of a fiber reinforcement method for enhancing the mechanical properties of chitosan scaffolds. Chitosan fibers were fabricated using a solution extrusion and neutralization method and incorporated into porous chitosan scaffolds. The effects of different fiber/scaffold mass ratios, fiber mechanical properties and fiber lengths on scaffold mechanical properties were studied. The results showed that incorporating fibers improved scaffold strength and stiffness in proportion to the fiber/scaffold mass ratio. A fiber-reinforced heart valve leaflet scaffold achieved strength values comparable to the radial values of human pulmonary and aortic valves. Additionally, the effects of shorter fibers (2 mm) were found to be up to 3-fold greater than longer fibers (10 mm). Despite this reduction in fiber mechanical properties caused by heparin crosslinking, the heparin-modified fibers still improved the mechanical properties of the reinforced scaffolds, but to a lesser extent than the unmodified fibers. The results demonstrate that chitosan fiber-reinforcement can be used to generate tissue-matching mechanical properties in porous chitosan scaffolds and that fiber length and mechanical properties are important parameters in defining the degree of mechanical improvement. We further studied various chemical and physical treatments to improve the mechanical properties of chitosan fibers. With combination of chemical and physical treatments, fiber stiffness improved 40fold compared to unmodified fibers. We also isolated ovine bone marrow-derived MSCs and evaluated their

  11. Healthy Heart Quizzes

    Science.gov (United States)

    ... 24,2016 Cardiovascular Conditions • Conditions Home • Arrhythmia and Atrial Fibrillation • Cardiac Arrest • Cardiac Rehab • Cardiomyopathy • Cardiovascular Conditions of Childhood • Cholesterol • Congenital Heart Defects • Diabetes • Heart Attack • Heart Failure (HF) • Heart Valve Problems and Disease • High Blood ...

  12. Travel and Heart Disease

    Science.gov (United States)

    ... Privacy Policy Cardiovascular Conditions • Conditions Home • Arrhythmia and Atrial Fibrillation • Cardiac Arrest • Cardiac Rehab • Cardiomyopathy • Cardiovascular Conditions of Childhood • Cholesterol • Congenital Heart Defects • Diabetes • Heart Attack • Heart Failure (HF) • Heart Valve Problems and Disease • High Blood ...

  13. Check valve

    International Nuclear Information System (INIS)

    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

  14. Emergency Transcatheter Aortic Valve Implantation for Acute and Early Failure of Sutureless Perceval Aortic Valve.

    Science.gov (United States)

    Durand, Eric; Tron, Christophe; Eltchaninoff, Hélène

    2015-09-01

    We report the case of a 78-year-old woman admitted for cardiogenic shock related to acute and early failure (severe aortic regurgitation) of a Perceval sutureless aortic bioprosthesis (Sorin Group, Saluggia, Italy). Clinical stability was achieved using rescue transfemoral transcatheter aortic valve-in-valve implantation with an Edwards SAPIEN 3 prosthesis (Edwards Lifesciences, Irvine, CA). To our knowledge, we report herein the first case of successful valve-in-valve implantation using a SAPIEN 3 transcatheter heart valve in a sutureless bioprosthetic aortic valve with acute and early deterioration. PMID:26095935

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

    OpenAIRE

    McElhinney, Doff B.; Hennesen, Jill T

    2013-01-01

    The Melody® transcatheter pulmonary valve (TPV) is a percutaneous valve system designed for the treatment of obstruction and/or regurgitation of prosthetic conduits placed between the right ventricle and pulmonary arteries in patients with congenital heart disease. In 2000, Melody TPV became the first transcatheter valve implanted in a human; in 2006 it became the first transcatheter valve commercially available anywhere in the world; and in 2010 it was launched as the first commercially avai...

  16. Practice and effects of self-management education for 62 patients after heart valve reiplacement surgery%62例心脏瓣膜置换术后自我管理教育的实践

    Institute of Scientific and Technical Information of China (English)

    陈玉梅; 龚兴媛; 李有金; 陈永祥; 汤敏敏

    2011-01-01

    This paper summarizes the practice of self-management education for 62 patients after heart valve replacement surgery. Self-management education was implemented at three days after admission,one day before operation,one day before discharge and six months after discharge by providing patients with Handbook of self-management after heart valve replacement surgery,Diary of self-management after heart valve replacement surgery. This practice motivated the patients' and family members' positivity in participation of self-management,promoted the patients to form healthy self-management behaviors and habits,reduced postoperative complications and improved patients' quality of life.%对62例心脏瓣膜置换术后患者进行了自我管理教育.通过发放《心脏瓣膜置换术后自我管理相关知识册》《心脏瓣膜置换术后自我管理监测日志》,以及医护合作的方法,分别在患者入院后、手术前、出院前、出院后进行自我管理教育,调动了患者及家属积极参与及学习自我管理方法的主动性,促使患者形成并坚持良好的自我健康管理行为习惯,减少了并发症,提高了生活质量.

  17. Depressurization valve

    International Nuclear Information System (INIS)

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

  18. Interventional treatment of common congenital heart diseases: the common view of Chinese medical experts. Part Four: Percutaneous balloon valvuloplasty for pulmonary and aortic valve stenosis

    International Nuclear Information System (INIS)

    Percutaneous balloon valvuloplasty has become the treatment of first choice for pulmonary valve stenosis. Congenital aortic valve stenosis can also be relieved by percutaneous balloon dilatation. Percutaneous valvuloplasty is indicated for patients with isolated pulmonary valve stenosis when the transvalvular peak systolic pressure gradient is over 40 mmHg and for patients with aortic valve stenosis when the pressure gradient exceeds 60 mmHg. A careful selection of patients, standardized procedure, individualized selection of the balloon type, size and length, and careful avoidance of any damage to chorda tendineae and to surrounding tissue are keys to achieving a successful procedure. Balloon valvuloplasty should be selectively performed in new-born and in infant since complications of the procedure are inversely related to age. (authors)

  19. Microstructure of Silicon-alloyed Pyrocarbon for Mechanical Heart Valves%人工心瓣含硅热解炭涂层的微观结构

    Institute of Scientific and Technical Information of China (English)

    张建辉; 孙海博; 王根明; 郭鹏海

    2011-01-01

    为了研究人工心瓣含硅热解炭涂层的微观结构,利用准稳态流化床反应装置制备出了含硅热解炭涂层,利用X射线衍射(XRD)、X射线能谱仪(EDS)、扫描电镜(SEM)、透射电镜(TEM)和偏光显微镜(PLM)对涂层微观结构进行了表征.结果表明,该涂层材料只有乱层结构热解炭和β型碳化硅两种物相,主要由直径为300 nm ~1μm的球形颗粒状碳结构组成,球形颗粒之间由片层状碳结构紧密相连,偶尔会形成闭合孔洞(直径约为0.1 ~1μm).涂层中硅元素宏观均匀分布且含量适中(6.48 wt%),直径约6~8nm的β型碳化硅晶粒无规则取向分布且存在微观尺度的集聚现象.含硅热解炭涂层的这些结构特征决定了其均匀致密、宏观各向同性的特性.%In order to study microstructure of silicon-alloyed pyrocarbon for mechanical heart valves, the silicon-alloyed pyrocarbon coating was prepared by a quasi-steady-state fluidized bed reactor. Microstructure of the coating was investigated by X-ray diffraction ( XRD ) , X-ray energy dispersive spectrometer ( EDS ) , scanning electron microscopy ( SEM ) , transmission electron microscopy ( TEM) and polarized light microscopy ( PLM). The results showed that the coating consisted of two phases, turbostratic pyrocarbon and (3 silicon carbide (β-SiC) , and was mainly composed of spherical particles that were from 300 nm to 1 μm in diameter. These spherical particles, between which there were occasionally pores (about 0. 1 - 1 μm in diameter) , were welded by laminar carbons. The silicon element whose content was moderate (6. 48 wt% ) distributed macro-unifonnly in the coating. The β-SiC grains about 6-8 nm in grain size distributed with random orientation and had some micro-scale agglomeration. These structural features of the silicon-alloyed pyrocarbon coating determined its uniform, dense and macroscopically isotropic properties.

  20. Has percutaneous aortic valve replacement taken center stage in the treatment of aortic valve disease?

    Science.gov (United States)

    Kumar, Gideon Praveen; Cui, Fangsen; Mathew, Lazar; Leo, Hwa Liang

    2013-01-01

    Modern biomedical advances have propelled percutaneous valve replacement into an effective and powerful therapy for many heart valve diseases, especially aortic valve stenosis. Experiences so far suggest that outcomes for new percutaneous valve replacement surgery compare favorably with that of traditional valve surgery in selected patients with severe symptomatic aortic stenosis. The inception of percutaneous aortic valve replacement (PAVR) began in 1992 when the potential for treating valve diseases was demonstrated through a modern technique of endoluminal deployment of a catheter-mounted crimped stented heart valve in an animal model. The first successful demonstration of such novel technique of surgical replacement of a heart valve was performed in 2002, when valve implantation in a patient with aortic stenosis was reported. Despite initial stumbles and a perception of being an uphill task, PAVR has emerged as one of the breakthroughs in surgical procedures. More than 1500 citations were found in PubMed, half of which were available after 2011. This is primarily because more than 50,000 procedures are being performed in more than 40 countries worldwide, with encouraging outcomes, and several stented valves have been launched in the market. This review provides a detailed analysis of the current state of the art of PAVR. Moreover, a competitive landscape of various devices available in the market and their design considerations, biomaterial selections, and overall hemodynamic performance are presented. PMID:24941416

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

    International Nuclear Information System (INIS)

    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

  2. Evolving Indications for Tricuspid Valve Surgery

    OpenAIRE

    McCarthy, Patrick M; Sales, Virna L.

    2010-01-01

    Opinion statement More attention has been paid to the mitral valve (MV) than the tricuspid valve (TV), and this relative paucity of data has led to confusion regarding the timing of TV surgery. We review the American College of Cardiology/American Heart Association and European Society of Cardiology guidelines to identify areas of concordance (severe tricuspid regurgitation [TR] in a patient undergoing mitral valve surgery); discordance (less than severe TR but with markers for late TR recurr...

  3. Heart Surgery Terms

    Science.gov (United States)

    ... Patients Choosing Wisely® Adult Cardiac Surgery What is Pediatric Heart Disease? What is Risk Adjustment? Valve Repair/Replacement Surgery Esophageal Surgery Lung/Thoracic Surgery Aneurysm Surgery Arrhythmia Surgery Other Types of Surgery Clinical ...

  4. Mitral valve prolapse - report of 3 cases

    Energy Technology Data Exchange (ETDEWEB)

    Han, Moon Hee; Im, Chung Ki; Im, Dong Ran; Han, Man Chung; Lee, Young Woo; Seo, Jung Don [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1979-12-15

    Prolapse of mitral valve is characterized by its unique auscultatory, echocardiographic and angiographic findings and may be associated with various disease entities such as congenital heart disease, coronary heart disease and Marfan's syndrome etc. Authors report recent experience of 3 cases of prolapsed mitral valve, 2 cases associated with A.S.D. and 1 case with Marfan's syndrome.

  5. All about Heart Rate (Pulse)

    Science.gov (United States)

    ... July 2015. Cardiovascular Conditions • Conditions Home • Arrhythmia and Atrial Fibrillation • Cardiac Arrest • Cardiac Rehab • Cardiomyopathy • Cardiovascular Conditions of Childhood • Cholesterol • Congenital Heart Defects • Diabetes • Heart Attack • Heart Failure (HF) • Heart Valve Problems and Disease • High Blood ...

  6. Heart failure - overview

    Science.gov (United States)

    ... Left or right ventricular assist device (LVAD) Total artificial heart At a certain point, the provider will ... American Heart Association Task Force on Practice Guidelines. Circulation . 2013;128:e240-e327. PMID: 23741058 www.ncbi. ...

  7. Perioperative anticoagulation for children with prosthetic mechanical valves.

    Science.gov (United States)

    Rees, P; Grech, V

    2000-04-01

    The insertion of a mechanical heart valve predisposes to thrombosis and embolism, and for this reason, individuals with mechanical valves who undergo dental/surgical procedures must take special precautions. In this article, we illustrate a protocol for anticoagulation during such procedures in individuals with mechanical valves. PMID:22368581

  8. Perioperative anticoagulation for children with prosthetic mechanical valves

    OpenAIRE

    Grech, Victor E.; Rees, P.

    2000-01-01

    The insertion of a mechanical heart valve predisposes to thrombosis and embolism, and for this reason, individuals with mechanical valves who undergo dental/surgical procedures must take special precautions. In this article, we illustrate a protocol for anticoagulation during such procedures in individuals with mechanical valves.

  9. Aortic valve calcification and mild tricuspid regurgitation but no clinical heart disease after 8 years of dopamine agonist therapy for prolactinoma

    NARCIS (Netherlands)

    M. Kars; V. Delgado (Victoria); E.R. Holman (Eduard); R.A. Feelders (Richard); J.W.A. Smit (Jan); J.A. Romijn (Johannes); J.J. Bax (Jeroen); A.M. Pereira (Alberto)

    2008-01-01

    textabstractObjective: Treatment with ergot-derived dopamine agonists, pergolide, and cabergoline has been associated with an increased frequency of valvular heart disease in Parkinson's disease. The aim of the present study was to assess the prevalence of valvular heart disease in patients treated

  10. 心脏瓣膜钙化与颈动脉内膜中层厚度的相关性研究%Relationship of Heart Valve Calcification and Carotid Intima Media Thickness

    Institute of Scientific and Technical Information of China (English)

    贾彦青; 党群; 姚民强; 李永健

    2012-01-01

    目的:研究心脏瓣膜钙化程度与颈动脉内膜中层厚度、斑块积分的相关性.方法:用经胸多普勒超声显像仪评估426例患者心脏瓣膜钙化情况,根据瓣膜钙化诊断标准将所有患者分为无钙化组、轻度钙化组、中度钙化组和重度钙化组.比较4组间的一般资料、病史、血压、血脂,同时测量4组患者颈动脉内膜中层厚度、软斑块积分、硬斑块积分及总斑块积分.结果:4组间的年龄、性别、体质量指数、吸烟情况、总胆固醇、三酰甘油、高密度脂蛋白胆固醇,低密度脂蛋白胆固醇差异无统计学意义;瓣膜钙化程度与冠心病患病率、收缩压、脉压、颈动脉内膜中层厚度、总斑块积分、硬斑块积分呈正相关(r.分别为0.546、0.628、0.512、0.802、0.628、0.544,均P<0.001),与舒张压、软斑块积分无相关性.结论:心脏瓣膜钙化程度可作为推测颈动脉内膜中层厚度、总斑块积分、硬斑块积分的一个重要指标.%Objective:To investigate the relationship between the degree of heart valve calcification and carotid intima media thickness and plaque integral. Methods: The valve calcification was assessed using transthoracic Doppler ultrasound imaging in 426 patients. All patients were divided into four groups according to the diagnostic criteria, including no calcification group, mild calcification group, moderate and severe calcification group. The general information, medical history, blood pressure, blood lipids were compared between four groups. The intima media thickness, suft plaque score, hard plaque score and the total plaque score of carotid artery were also measured in patients of four groups. Results: There were no significant differences in age, gender, body mass index, smoking status, total cholesterol, triglycerides, high density lipoprotein and low density lipoprotein between four groups. The degree of valve calcification was positively correlated with

  11. Flow field analysis of mechanical heart valves. Comparison of Starr-Edwards, Bjork-Shiley c-c, and St. Jude medical prostheses; Kikaiteki jinkoben no nagareba no kaiseki. Starr-Edwards, Bjork-Shiley c-c, oyobi St. Jude Medical ben no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Akutsu, T. [Kanto Gakuin University, Yokohama (Japan); Bishop, W. [Andronic Inc., Richmond, BC, (Canada); Modi, V. [University of British Columbia, Vancouver, BC (Canada)

    1996-03-25

    Three typical mechanical heart valves (Starr-Edwards, Bjork-Shiley c-c and St. Jude Medical) have been tested in the mitral position under pulsatile flow conditions. The test program included measurements of velocity and turbulent stresses at six downstream locations. The study was carried out using a sophisticated cardiac simulator in conjunction with a highly sensitive two-component laser Doppler anemometer system. The continuous monitoring of parametric time histories revealed useful details about the complex flow and also helped established location and time of the peak parameter values. Based on the experimental data, the following general conclusions can be drawn: (1) all 3 valve designs generated elevated turbulent stresses during acceleration and peak flow phases, presenting a possibility of thromboembolism, and perhaps, hemolysis; (2) valve configuration and valve orientation significantly affect the flow characteristics; (3) the Starr-Edwards valve with relatively a small opening area shows lower turbulent stresses; and (4) the bileaflet design of the St. Jude Medical valve is also associated with lower turbulent stresses, as compared to the Bjork-Shiley c-c valve. 7 refs., 14 figs.

  12. Transcatheter aortic valve replacement in elderly patients

    Institute of Scientific and Technical Information of China (English)

    Dimytri Siqueira; Alexandre Abizaid; Magaly Arrais J.; Eduardo Sousa

    2012-01-01

    Aortic stenosis is the most common native valve disease, affecting up to 5% of the elderly population. Surgical aortic valve replacement reduces symptoms and improves survival, and is the definitive therapy in patients with symptomatic severe aortic stenosis. However, despite the good results of classic surgery, risk is markedly increased in elderly patients with co-morbidities. Transcatheter aortic valve replacement (TAVR) allows implantation of a prosthetic heart valve within the diseased native aortic valve without the need for open heart surgery and cardiopulmonary bypass, offering a new therapeutic option to elderly patients considered at high surgical risk or with contraindications to surgery. To date, several multicenter registries and a randomized trial have confirmed the safety and efficacy of TAVR in those patients. In this chapter, we review the background and clinical applications of TAVR in elderly patients.

  13. Native Valve Bacillus cereus Endocarditis in a Non-Intravenous-Drug-Abusing Patient

    OpenAIRE

    Thomas, Benjamin S.; Bankowski, Matthew J.; Lau, William K. K.

    2012-01-01

    Bacillus cereus is a rare cause of endocarditis, typically associated with intravenous drug abuse, rheumatic heart disease, prosthetic heart valves, pacemakers, or immunodeficiency. We present the first case of native valve Bacillus cereus endocarditis with no apparent risk factors. The patient had a fulminant course requiring emergent valve replacement.

  14. Infection and twiddler syndrome in a dog with addison's disease, complete heart block, and wandering artificial pacemakers

    International Nuclear Information System (INIS)

    Third degree heart block developed in an obese, 10-year-old Labrador retriever with adrenocortical failure. A permanent transthoracic pacemaker was fitted, but the pulse generator migrated 2 years later, to the ventral part of the flank, where an abscess formed. A new pacemaker was fitted, but also migrated and rotated and a syndrome analogous to Twiddler's syndrome in man developed. After a further 2 years the second pacemaker was located, encapsulated within the right pleural cavity. Culture of the brownish exudate around the pulse generator yielded Pseudomonas sp

  15. Investigations into the myocardial metabolism of 123-I-ω-HDA in patients showing the clinical signs and symptoms of mitral valve prolapse and previously proven to have no coronary heart disease

    International Nuclear Information System (INIS)

    In 53 patients showing the clinical signs and symptoms of mitral valve prolapse (MVP) where coronary heart disease (CHD) had previously been excluded by angiography the myocardial metabolism of fatty acids was examined at rest using metabolic myocardial scintigraphy (MMS) and 123-I-ω-HDA as tracer substance. The results were correlated with those obtained by other methods of investigation (findings at rest and during exercise from ECG recordings, tests using a flow-guided catheter and radionuclide ventriculography, further from echocardiography as well as myocardial Tl redistribution scintiscanning during exercise). For purposes of reference, MMS was additionally carried out in twelve normal individuals subjected to coronary angiography to exclude both MVP and CHD. The results of this study would appear to suggest that the pathological findings revealed by myocardial Tl scintigraphy in patients showing symptoms of MVP cannot invariably be classified as 'false' but are at least to some extent attributable to impaired myocardial perfusion, vitality or metabolism. (orig./MG)

  16. Cardiopatía, embarazo y tratamiento anticoagulante Anticoagulant therapy in pregnant women with mechanical valve prosthesis and/or heart diseases

    OpenAIRE

    Sandra Braun J

    1999-01-01

    Pregnancy is a hypercoagulable state. Some women with cardiac disease and mechanical valve prosthesis are at increased risk of arterial thromboembolic phenomena. These women are maintained on oral anticoagulants and require effective permanent prophylaxis during pregnancy. The use of oral anticoagulants during pregnancy is controversial because of the risks of embriopathy (Chondrodysplasia punctata) in fetuses who are exposed to coumarin between the 6th and 9th week of gestation, the risk of ...

  17. The mechanical heart valve replacement surgery in the treatment of rheumatic heart disease in patients with atrial fibril ation psychological care%机械瓣膜替换术治疗风湿性心脏病合并心房颤动患者的心理护理

    Institute of Scientific and Technical Information of China (English)

    易红梅; 杜建文; 胡丽娟; 徐丽; 冯丽花

    2013-01-01

    目的:探讨使用机械瓣膜替换手术治疗风湿性心脏病合并房颤患者手术后给予心理护理的效果。方法以78例风湿性心脏病合并房颤患者为临床研究对象,患者均采用机械瓣膜替换手术,对照组给予常规护理,实验组给予围手术期心理护理,对比观察患者的护理效果。结果实验组患者围手术期心理焦虑程度较低,患者睡眠质量更好,出院后生活幸福感高,与对照组比较有显著差异,p<0.05。结论在机械瓣膜替换术治疗风湿性心脏病合并心房颤动患者护理工作中加强心理护理具有较好的效果。%Objective: To investigate the effect of psychological care given after surgical treatment of rheumatic heart disease in patients with atrial fibril ation surgery using a mechanical valve replacement. : 78 patients with rheumatic heart disease patients with atrial fibril ation clinical study, patients were treated with mechanical heart valve replacement surgery, the control group received conventional care, the experimental group were given perioperative psychological care, compared to observe the effect of the patient's care. Results: The experimental group patients perioperative the mental anxiety level is lower, the better quality of sleep in patients, the happiness of life after discharge, compared with the control group, a significant difference, p <0.05. Conclusion: The mechanical heart valve replacement surgery in the treatment of rheumatic heart disease in patients with atrial fibril ation care, strengthen psychological care with good results.

  18. [Valve-in-valve with Portico valve for a degenerative bioprosthetic surgical valve (Biocor)].

    Science.gov (United States)

    Latini, Roberto Adriano; Testa, Luca; Brambilla, Nedy; Tusa, Maurizio; Bedogni, Francesco

    2016-04-01

    In the last years, a general shift toward the use of surgical bioprosthetic aortic valves rather than mechanical valves with subsequent less use of anticoagulant therapy has been observed. However, bioprosthetic valves have limited durability. Reoperation, the current standard of care for these patients, carries a high surgical risk, especially because patients are elderly and with numerous comorbidities. Recently, transcatheter aortic valve replacement within a failed bioprosthetic valve (valve-in-valve procedure) has proven feasible. We here describe a case of valve-in-valve procedure with a Portico valve placed in a purely insufficient bioprosthetic valve (Biocor). PMID:27093211

  19. Hemodynamics driven cardiac valve morphogenesis.

    Science.gov (United States)

    Steed, Emily; Boselli, Francesco; Vermot, Julien

    2016-07-01

    Mechanical forces are instrumental to cardiovascular development and physiology. The heart beats approximately 2.6 billion times in a human lifetime and heart valves ensure that these contractions result in an efficient, unidirectional flow of the blood. Composed of endocardial cells (EdCs) and extracellular matrix (ECM), cardiac valves are among the most mechanically challenged structures of the body both during and after their development. Understanding how hemodynamic forces modulate cardiovascular function and morphogenesis is key to unraveling the relationship between normal and pathological cardiovascular development and physiology. Most valve diseases have their origins in embryogenesis, either as signs of abnormal developmental processes or the aberrant re-expression of fetal gene programs normally quiescent in adulthood. Here we review recent discoveries in the mechanobiology of cardiac valve development and introduce the latest technologies being developed in the zebrafish, including live cell imaging and optical technologies, as well as modeling approaches that are currently transforming this field. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel. PMID:26608609

  20. Mechanical aortic valve without anticoagulation for 33 years in a Yemeni man: a case report

    OpenAIRE

    Aman, Khadija

    2016-01-01

    Background Mechanical prosthetic heart valves have been used for many decades to replace damaged native valves. Guidelines mandate the use of anticoagulant therapy in patients with mechanical prosthetic valves of any type, irrespective of the position in the heart. The rationale for this is to prevent valve thrombosis and thromboembolic complications without increasing the risk of excess bleeding. We report a case involving a patient with a functioning aortic mechanical valve without any anti...

  1. Coronary embolism in a patient with mitral valve prosthesis: successful management with tirofiban and half-dose tissue-type plasminogen activator

    Institute of Scientific and Technical Information of China (English)

    Yusuf Atmaca; Cagdas Ozdol; Cetin Erol

    2007-01-01

    @@ Coronary embolism has been considered as a rare cause of coronary occlusion.Prosthetic heart valve is an infrequent cause of this condition.The exact incidence of coronary embolization in patients with prosthetic heart valves is not well known.

  2. Piezoelectric valve

    Science.gov (United States)

    Petrenko, Serhiy Fedorovich

    2013-01-15

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

  3. Keeping Your Heart Healthy After Treatment for Childhood Cancer

    Science.gov (United States)

    ... ventricles) within the heart that work together to pump blood. Valves direct the flow of blood through the ... arrhythmia), or an inability of the heart to pump blood properly (congestive heart failure). Which types of cancer ...

  4. Heart Failure in Children and Adolescents

    Science.gov (United States)

    ... of the heart. It's then pumped into the aorta, which distributes it throughout the body to provide ... due to effects of smoking, high blood pressure, diabetes, coronary artery disease and bad heart valves. It ...

  5. Bioprótese aórtica porcina "Stentless": acompanhamento clínico a médio prazo Porcine Stentless heart valve substitutes: technical and clinical mid-term follow-up

    Directory of Open Access Journals (Sweden)

    Mário O Vrandecic

    1994-03-01

    hemodinâmico podem ser detectados. Concluímos que, a médio prazo, a bioprótese aórtica sem suporte, Biocor apresentou ótimos resultados clínicos e excelente desempenho hemodinâmico. Um seguimento mais longo ainda é necessário.From May 1990 to January 1994, one hundred and twenty (120 patients underwent aortic valve replacement with the use of the porcine aortic stentless valve. This group comprised of eighty-three (83 male and thirty-seven (37 female patients. The age ranged from eleven (11 to seventy-six (76 years with a mean of 36. There were 85 patients under 40 years of age. Sixty-four patients (64 underwent their first aortic valve replacement due to rheumatic heart disease, thirty (30 because of prosthetic valve failure and of those: twenty (20 due primary tissue failure and in ten (10 due to prosthetic endocarditis, native aortic bicuspid valve in eleven (11 and senile calcificant aortic valve disease in four (4. Thirty-three (33 patients had aortic annular related pathology. The functional class revealed sixty-one (61 patients in class III and fifty-nine (59 in class IV. The longest follow-up was 42 months with a mean of 26. The surgical technique used in the aortic valve surgery rendered consistent and reproducible results. The hospital mortality was 5% (6 patients. This mortality was not valve related. The hospital morbidity revealed full recovery of all patients. There were four (4 late reoperations, in two (2 due to recurrent endocarditis and in two (2 because of paravalvar leak. All patients had full recovery after the reoperation. There was a late mortality of six (6 patients (non valve related. The follow-up of these patients revealed full competent valve in ninety-seven (97 patients and only minor jet in nine (9. Most patients are in functional class I and II. The stentless concept has proven to be outstanding in the aortic position throughout the current follow-up. Although the test of time is required, we have gained confidence in the procedure

  6. Micropump and venous valve by micro stereo lithography

    Science.gov (United States)

    Varadan, Vijay K.; Varadan, Vasundara V.

    2000-06-01

    Micro Stereo Lithography (MSL) is a poor man's LIGA for fabricating high aspect ratio MEMS devices in UV curable semiconducting polymers using either two computer-controlled low inertia galvanometric mirrors with the aid of focusing lens or an array of optical fibers. For 3D MEMS devices, the polymers need to have conductive and possibly piezoelectric or ferroelectric properties. Such polymers are being developed at Penn State resulting in microdevices for fluid and drug delivery. Applications may include implanted medical delivery system, artificial heart valves, chemical and biological instruments, fluid delivery in engines, pump coolants and refrigerants for local cooling of electronic components. With the invention of organic thin film transistor, now it is possible to fabricate 3D polymeric MEMS devices with built-in-electronics similar to silicon based microelectronics.

  7. Drug-related cardiac valve disease.

    Science.gov (United States)

    2013-12-01

    Cardiac valve disease can involve one or more of the four heart valves. Chronic valve damage may remain asymptomatic for long periods but ultimately leads to haemodynamic overload of the heart. The most common causes of valve disease are rheumatic diseases, infections, chronic renal failure, malformations, and genetic diseases. Valve disease is often attributed to degeneration with no known cause.The frequency of drug-related valve disease has long been underestimated. Most implicated drugs have serotonergic properties, such as fenfluramine-derived amphetamines, including benfluorex. Rye ergot derivatives can also be implicated: these include dopamine agonists (bromocriptine, lisuride, pergolide and cabergoline), migraine treatments (methysergide, ergotamine and dihydroergotamine), and drugs used for cognitive and neurosensory deficits (nicergoline, dihydroergocryptine, etc.). "Ecstasy", an amphetamine, is sometimes also involved. The risk increases after a few months of exposure. Drug withdrawal is sometimes followed by an improvement. Patients exposed to a drug known to cause valve damage should be informed of the risk and receive long-term monitoring to detect these lesions before they become irreversible. The possible role of a drug should always be considered when cardiac valve disease is diagnosed, in order to facilitate active research and to avoid exposing other patients to this risk. PMID:24600729

  8. Mitral valve disease--morphology and mechanisms.

    Science.gov (United States)

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

    2015-12-01

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

  9. Mechanical ventilation and the total artificial heart: optimal ventilator trigger to avoid post-operative autocycling - a case series and literature review

    Directory of Open Access Journals (Sweden)

    Arabia Francisco A

    2010-05-01

    Full Text Available Abstract Many patients with end-stage cardiomyopathy are now being implanted with Total Artificial Hearts (TAHs. We have observed individual cases of post-operative mechanical ventilator autocycling with a flow trigger, and subsequent loss of autocycling after switching to a pressure trigger. These observations prompted us to do a retrospective review of all TAH devices placed at our institution between August 2007 and May 2009. We found that in the immediate post-operative period following TAH placement, autocycling was present in 50% (5/10 of cases. There was immediate cessation of autocycling in all patients after being changed from a flow trigger of 2 L/minute to a pressure trigger of 2 cm H2O. The autocycling group was found to have significantly higher CVP values than the non-autocycling group (P = 0.012. Our data suggest that mechanical ventilator autocycling may be resolved or prevented by the use of a pressure trigger rather than a flow trigger setting in patients with TAHs who require mechanical ventilation.

  10. Oxygenation to Bovine Blood in Artificial Heart and Lung Using Vibrating Flow Pump: Experiment and Numerical Analysis Based on Non-Newtonian Model

    Science.gov (United States)

    Shintaku, Hirofumi; Yonemura, Tsubasa; Tsuru, Kazuaki; Isoyama, Takashi; Yambe, Tomoyuki; Kawano, Satoyuki

    In this study, we construct an experimental apparatus for a prototype artificial heart and lung (AHL) by installing hollow fibers into the cylindrical tube of the vibrating flow pump (VFP). The oxygenation characteristics are investigated both by experiments using bovine blood and by numerical analyses based on the computational fluid dynamics. The analyses are carried out at the Reynolds numbers Re ranged from O(1) to O(103), which are determined based on the experimental conditions. The blood flow and the diffusion of oxygen gas are analyzed based on the Newtonian/non-Newtonian, unsteady, incompressible and axisymmetric Navier-Stokes equations, and the advection-diffusion equation. The results show that the oxygenation rate increases in proportion to Re1/3, where the phenomenon corresponds to the decreasing thickness of the concentration boundary layer with Re. Although the effects of the vibrating flow and the rheology of the blood are clearly appeared on the velocity field, their effects on the gas exchange are relatively small at the ranges of prescribed Reynolds numbers. Furthermore, the numerical results in terms of the oxygenation rate are compared with the experimental ones. The basic design data of VFP were accumulated for the development of AHL in the clinical applications.

  11. Valve's Way

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Dobrajska, Magdalena

    2015-01-01

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

  12. Heart valve disease associated with treatment with ergot-derived dopamine agonists: a clinical and echocardiographic study of patients with Parkinson's disease

    DEFF Research Database (Denmark)

    Rasmussen, Vibeke Guldbrand; Poulsen, Steen Hvitfeldt; Dupont, E;

    2007-01-01

    .2% (P < 0.05). The sensitivity of detecting at least moderate valvular disease by cardiac murmur, dyspnoea, or the heart failure marker NT-proBNP (natriuretic peptide) was 62% for the neurologists and 93% for the cardiologist but with equally low specificity (30-35%). CONCLUSION: EDDA was associated...

  13. Review of Ten Years' Use of St. Jude Medical Prosthetic Valve Replacement and Postoperative Management at Niigata University Hospital

    OpenAIRE

    Hayashi, Jun-Ichi; Oguma, Fumiaki; Tsuchida, Sho-ichi; Fujita, Yasuo; Nakazawa, Satoshi; Miyamura, Haruo; Eguchi, Shoji

    1993-01-01

    A ten-year period of using St. Jude Medical (SJM) prosthetic heart valves at Niigata University Hospital was reviewed. Between December 1979 and August 1990, 261 patients, 118 males and 143 females, ages ranging 6-75 years, underwent SJM prosthetic valve replacement. Aortic valve replacement was performed in 72 patients, mitral valve replacement in 140 patients, combined aortic and mitral valve replacement in 37 patients, and miscellaneous valve replacement in 12 patients. The actuarial survi...

  14. 机械心脏瓣膜术后患者自我管理行为的研究%Research for self- management action of patient suffered from mechanical heart valve post-operation

    Institute of Scientific and Technical Information of China (English)

    李飞霞; 袁述兰; 梁克

    2011-01-01

    目的 探讨机械心脏瓣膜术后患者行为的自我管理.方法 将168例机械心脏瓣膜术后患者随机分为干预组86例和对照组82例.干预组患者在常规药物治疗的同时给予有针对性的自我管理教育,而对照组患者在常规药物治疗的同时则行常规健康教育,分别于治疗护理1年后采用"自我管理行为量表"对两组患者进行测定,评估两组患者的自我管理行为,并应用中文版SF-36量表对两组患者进行评价,比较两组患者的生活质量(QOL).结果 治疗护理1年后,干预组患者的自我管理行为量表及SF-36量表的各项评分均明显高于对照组,两组比较差异均有统计学意义(P<0.01).结论 自我管理教育可帮助患者建立良好的健康行为模式,能提高患者自我管理疾病的能力,减少并发症的发生,从而促进康复,达到提高机械心脏瓣膜术后患者生活质量的目的.%Objective To explore the self-management action of patient suffered from mechanical heart valve post-operation. Methods 168cases of the patients suffered from the mechanical heart valve post-operation were separately divided into 86 cases as the interference group and 82 cases as control group at random. The interference group was given for the normal medical treatment and also objective self-management education but the control group used normal medical treatment and also health education. Two groups of the patients were tested by "Self-Management Action Measurement Form" separately to asseSS the self-management action and also were assessed by Chinese version of SF-36 Measurement Form for the assessment of two groups of the patients for the comparison of the patients of two groups in living quality(QOL) one year after treatment and nursing. Results The various items of assessments of interference group were higher than the comparison group in self-management action measurement form SF-36 Measurement Form with the difference of statistics meaning

  15. Aortic Valve Sparing in Different Aortic Valve and Aortic Root Conditions.

    Science.gov (United States)

    David, Tirone E

    2016-08-01

    The development of aortic valve-sparing operations (reimplantation of the aortic valve and remodeling of the aortic root) expanded the surgical armamentarium for treating patients with aortic root dilation caused by a variety of disorders. Young adults with aortic root aneurysms associated with genetic syndromes are ideal candidates for reimplantation of the aortic valve, and the long-term results have been excellent. Incompetent bicuspid aortic valves with dilated aortic annuli are also satisfactorily treated with the same type of operation. Older patients with ascending aortic aneurysm and aortic insufficiency secondary to dilated sinotubular junction and a normal aortic annulus can be treated with remodeling of the aortic root or with reimplantation of the aortic valve. The first procedure is simpler, and both procedures are likely equally effective. As with any heart valve-preserving procedure, patient selection and surgical expertise are keys to successful and durable repairs. PMID:27491910

  16. Transapical transcatheter aortic valve implantation in a complex aortic surgical patient: A case involving the youngest valve-in-valve implantation with a 29 mm transcather valve

    OpenAIRE

    Attia, Rizwan; Visagan, Ravi; Nowell, Justin; Chadalavada, Sucharitha; Thomas, Martyn; Bapat, Vinne

    2012-01-01

    The present article reports a case involving a 29-year-old man who developed severe cardiac failure (New York Heart Association class IV). He had a complex surgical history, beginning with the repair of an anterior sinus of Valsalva aneurysm and closure of a ventricular septal defect at eight months of age. His residual Valsalva aneurysm and mixed aortic valve disease necessitated mechanical aortic valve replacement at 14 years of age. One year later, he developed coagulase-negative staphyloc...

  17. Types of Congenital Heart Defects

    Science.gov (United States)

    ... Thus, the heart has to work harder to pump blood through the valve. Atresia (ah-TRE-ze-AH). ... right ventricle can get very overworked trying to pump blood to the pulmonary artery. These infants may have ...

  18. Aortic valve bypass

    DEFF Research Database (Denmark)

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

    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...

  19. Preliminary MRI study on hemodynamics after prosthetic cardiac valve implantation

    International Nuclear Information System (INIS)

    Objective: To assess the function of prosthetic valve by magnetic resonance imaging (MRI), and to measure the blood velocity downstream of prosthetic valve and three-dimensional surface profiles so as to provide the original materials for appearance and development of thrombi-embolic complications in the long time follow-up. Methods: Twenty-seven cases with prosthetic aortic valve were examined and the blood velocity was measured by using MRI. The diseased heart valves were replaced with two prosthetic valves in 20 cases, and replaced with single prosthetic valve in 7 cases. The axial velocity components were measured at three positions near the valve including half, one, and two diameter downstream in the ascending aorta. Two and three-dimensional surface profile reconstruction were analyzed by using flow analysis software and Matlab 6.5 software. Results: In 16 cases with prosthetic aortic valve replacement with two leaflets prosthetic valves, the velocity profiles downstream of the valve prosthetic reflecting the valve design was nearly three velocity, jets of the two major orifices and the central slit between the two leaflets. In 4 cases with prosthetic aortic valve replace with Sorin two leaflets prosthetic valve, the velocity profiles downstream was nearly two velocity jets of the two major orifices. In 20 cases replaced with two leaflets prosthetic valves, blood velocity profiles were skewed with highest velocities. Seven cases with single leaflet showed single velocity jets of the major orifices at peak systole. Retrograde velocities occurred in part of the lateral orifice regions in 26 cases. Three-dimensional surface profiles downstream of the prosthetic aortic valve reflected the valve design. The blood velocity profiles with prosthetic aortic valve in the one diameter downstream in the ascending aorta clearly showed the valve design. Conclusion: MRI is a non-invasive, direct, and in-vivo method of choice to assess the valvular function and is the

  20. Protect Your Heart in the Heat

    Science.gov (United States)

    ... For Seniors Cardiovascular Conditions • Conditions Home • Arrhythmia and Atrial Fibrillation • Cardiac Arrest • Cardiac Rehab • Cardiomyopathy • Cardiovascular Conditions of Childhood • Cholesterol • Congenital Heart Defects • Diabetes • Heart Attack • Heart Failure (HF) • Heart Valve Problems and Disease • High Blood ...