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Sample records for heart valve prostheses

  1. Retroca valvular Replacement of heart valves prostheses

    Directory of Open Access Journals (Sweden)

    Pablo M. A Pomerantzeff

    1987-12-01

    replacement, at our Institution. These patients received a total of 157 prostheses and 4 had their Starr-Edwards valve ball replaced due to ball variance. Six patients were submitted to a third valvular replacement in the mitral position, withouth deaths. Nine patients had a third valvular replacement in the aortic position with 1 death in the immediate postoperative period. Rupture or calcification of the dura mater leaflets were the main reason for the indication of prosthetic replacement. In the mitral position 41 patients presented rupture of the leaflets and 19 showed calcification. In the aortic position 32 bioprostheses underwent rupture and 12, calcification. Bio-prostheses were utilized in the majority of cases of replace the dysfunctioning prostheses. Porcine bioprostheses were implanted in 63 cases and bovine pericardial bioprostheses, in 35. Immediate mortality was 8.3% (12 patients; low cardiac output was the main cause of death. The most frequent immediate complications were low cardiac output, arrhythmias and bleeding. In the preoperative period 90% of the patients were in functional classes III and IV (NYHA. After the replacement, 89% of the aortics and 82% of the mitral were in functional classes I an II.

  2. A low-volume tester for the thrombogenic potential of mechanical heart valve prostheses.

    Science.gov (United States)

    Linde, Torsten; Hamilton, Kathrin F; Timms, Daniel L; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2011-09-01

    During the development of a mechanical heart valve prosthesis, many studies are conducted to guarantee its correct function. Currently, investigations into the thrombogenic potential of a valve after its replacement are conducted with expensive and time-consuming chronic animal trials. Hence, the study aim was to develop and test an alternative system to resolve such thrombogenic issues. The Thrombosis Tester of the Helmholtz Institute Aachen (THIA II) has a reasonably small priming volume (220-270 ml) that allows analysis of the thrombogenic potential of two valves, using one human blood bottle. Hydrodynamic evaluation demonstrated an absolutely stable physiological pressure and flow progression at the aortic and pulmonary positions. A sinus geometry of the human aortic root is implemented downstream of the valve in order to guarantee physiological leaflet motion. The tester remained absolutely thrombus-free during several tests carried out with minimally anticoagulated porcine blood, while the valves showed reproducible thrombus formation in reasonable locations. Tests with fully heparinized porcine blood showed that a soft silicon fixture for the valve could reduce hemolysis in the THIA II. This in-vitro test protocol can enable the optimization of a valve design during the early stages of its research and development. The system can provide a unique and suitable supplement to animal trials for testing thrombogenic performance, under constant and reproducible boundary conditions, including considerable physiological and pathological circumstances such as the influence of valve position (aortic, pulmonic), and a comparison of different valve types.

  3. Evaluation of the marker of hypercoagulability prothrombin fragment F 1+2 in patients with mechanical or biological heart valve prostheses

    Directory of Open Access Journals (Sweden)

    Claudia Natália Ferreira

    2002-11-01

    Full Text Available OBJECTIVE: To investigate whether patients with heart valve prostheses and similar International Normalized Ratios (INR have the same level of protection against thromboembolic events, that is, whether the anticoagulation intensity is related to the intensity of hypercoagulability supression. METHODS: INR and plasma levels of prothrombin fragment 1+2 (F1+2 were assessed in blood samples of 27 patients (7 with mechanical heart valves and 20 with biological heart valves and 27 blood samples from healthy donors that were not taking any medication. RESULTS: Increased levels of F1+2 were observed in blood samples of 5 patients with heart valve prostheses taking warfarin. These findings reinforce the idea that even though patients may have INRs, within the therapeutic spectrum, they are not free from new thromboembolic events. CONCLUSION: Determination of the hypercoagulability marker F1+2 might result in greater efficacy and safety for the use of oral anticoagulants, resulting in improved quality of life for patients.

  4. Heart valve surgery

    Science.gov (United States)

    Valve replacement; Valve repair; Heart valve prosthesis; Mechanical valves; Prosthetic valves ... can relieve your symptoms and prolong your life. Mechanical heart valves do not often fail. However, blood clots can ...

  5. Cyclic stress-strain behavior of polymeric nonwoven structures for the use as artificial leaflet material for transcatheter heart valve prostheses

    Directory of Open Access Journals (Sweden)

    Arbeiter Daniela

    2017-09-01

    Full Text Available Xenogenic leaflet material, bovine and porcine pericardium, is widely used for the fabrication of surgically implanted and transcatheter heart valve prostheses. As a biological material, long term durability of pericardium is limited due to calcification, degeneration and homogeneity. Therefore, polymeric materials represent a promising approach for a next generation of artificial heart valve leaflets with improved durability. Within the current study we analyzed the mechanical performance of polymeric structures based on elastomeric materials. Polymeric cast films were prepared and nonwovens were manufactured in an electrospinning process. Analysis of cyclic stress-strain behavior was performed, using a universal testing machine. The uniaxial cyclic tensile experiments of the elastomeric samples yielded a non-linear elastic response due to viscoelastic behavior with hysteresis. Equilibrium of stress-strain curves was found after a specific number of cycles, for cast films and nonwovens, respectively. In conclusion, preconditioning was found obligatory for the evaluation of the mechanical performance of polymeric materials for the use as artificial leaflet material for heart valve prostheses.

  6. Implications of using different methods to characterise anticoagulant control in patients with second generation mechanical heart valve prostheses.

    Directory of Open Access Journals (Sweden)

    Francesca Fiorentino

    Full Text Available Characterisation of anticoagulant control is fundamental to investigations of its association with clinical outcome. Anticoagulant control depends on several factors. This paper aims to illustrate the implications of different methods for measuring and analysing anticoagulant control in patients with second generation mechanical heart valve prostheses.International normalised ratio (INR data collected during the 10-year follow-up of a randomised controlled trial were analysed. We considered the influence of: 3 different target INR ranges; anticoagulant control expressed as the proportion of INR readings (PoR vs. anticoagulant control follow-up time (PoT; 3 ways of describing the profile of anticoagulant control over time.Different target INR ranges dramatically influenced derived measures of anticoagulant control; the PoT within the target range varied from 88% for the widest to 28% for narrowest range. Overall distributions of PoR and PoT observations were similar but differed by up to ± 20% for individuals; PoT exceeded PoR when control was good but was less than PoR when control was poor. Classifying PoT outside the target range showed that widely varying combinations of PoT too high and too low are possible across individuals.Researchers' choices about methods for measuring and quantifying anticoagulant control markedly influence the values derived from INR readings. The use of different methods across studies makes it difficult or impossible to compare findings and to establish an evidence base for clinical practice. Methods for quantifying anticoagulant control should be standardised.

  7. 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 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. © IMechE 2016.

  8. Risks for Heart Valve Problems

    Science.gov (United States)

    ... Thromboembolism Aortic Aneurysm More Risks for Heart Valve Problems Updated:Jan 18,2017 Who is at risk ... content was last reviewed May 2016. Heart Valve Problems and Disease • Home • About Heart ValvesHeart Valve ...

  9. 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 ...

  10. What Is Heart Valve Disease?

    Science.gov (United States)

    ... Heart Valves Sometimes heart valves can’t be repaired and must be replaced. This surgery involves removing the faulty valve and replacing it with a man-made or biological valve. Biological valves are made ...

  11. Platelet thrombosis in cardiac-valve prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Dewanjee, M.K.

    1989-01-01

    The contribution of platelets and clotting factors in thrombosis on cardiovascular prostheses had been quantified with several tracers. Thrombus formation in vivo could be measured semiquantitatively in animal models and patients with indium-111, Technetium-99m labeled platelets, iodine-123, iodine-131 labeled fibrinogen, and In-111 and Tc-99m labeled antibody to the fibrinogen-receptor on the platelet- membrane, or fibrin. The early studies demonstrated that certain platelet-inhibitors, e.g. sulfinpyrazone, aspirin or aspirin- persantine increased platelet survival time with mechanical valves implanted in the baboon model and patients. Thrombus localization by imaging is possible for large thrombus on thrombogenic surface of prosthesis in the acute phase. The majority of thrombus was found in the sewing ring (Dacron) in the acute phase in both the mechanical and tissue valves. The amount of retained thrombus in both mechanical and tissue valves in our one-day study in the dog model was similar (< 1% if injected In-111 platelets = 5 billion platelets). As the fibrous ingrowth covered the sewing ring, the thrombus formation decreased significantly. Only a small amount of thrombus was found on the leaflets at one month in both the dog and calf models. 38 refs., 9 figs., 5 tabs.

  12. Living with Heart Valve Disease

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  13. What Causes Heart Valve Disease?

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  14. Bioprosthetic heart valves of the future.

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    Manji, Rizwan A; Ekser, Burcin; Menkis, Alan H; Cooper, David K C

    2014-01-01

    Glutaraldehyde-fixed bioprosthetic heart valves (GBHVs), derived from pigs or cows, undergo structural valve deterioration (SVD) over time, with calcification and eventual failure. It is generally accepted that SVD is due to chemical processes between glutaraldehyde and free calcium ions in the blood. Valve companies have made significant progress in decreasing SVD from calcification through various valve chemical treatments. However, there are still groups of patients (e.g., children and young adults) that have accelerated SVD of GBHV. Unfortunately, these patients are not ideal patients for valve replacement with mechanical heart valve prostheses as they are at high long-term risk from complications of the mandatory anticoagulation that is required. Thus, there is no "ideal" heart valve replacement for children and young adults. GBHVs represent a form of xenotransplantation, and there is increasing evidence that SVD seen in these valves is at least in part associated with xenograft rejection. We review the evidence that suggests that xenograft rejection of GBHVs is occurring, and that calcification of the valve may be related to this rejection. Furthermore, we review recent research into the transplantation of live porcine organs in non-human primates that may be applicable to GBHVs and consider the potential use of genetically modified pigs as sources of bioprosthetic heart valves. © 2014 John Wiley & Sons A/S.

  15. Resurgery for recurrent heart valve diseases

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    Chong-lei REN

    2017-02-01

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

  16. Problem: Heart Valve Regurgitation

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    ... State SELECT YOUR LANGUAGE Español (Spanish) 简体中文 (Traditional Chinese) 繁体中文 (Simplified Chinese) Tiếng Việt (Vietnamese) Healthy Living for Heart.org ... should be completely closed For example: Watch an animation of mitral valve regurgitation A leaking mitral valve ...

  17. Renal Haemosiderosis in Patients with· Prosthetic Heart Valves

    African Journals Online (AJOL)

    1974-04-13

    Apr 13, 1974 ... Prosthetic Heart Valves. A. G. ROSE. SUMMARY. Renal haemosiderosis is the anatomical indicator of intra- vascular haemolysis. The incidence of renal haemosiderosis was studied in 66 patients with valve prostheses, 32 patients with advanced rheumatic-type valvular deformities and in 21 consecutive ...

  18. When a Heart Murmur Signals Valve Disease

    Science.gov (United States)

    ... Order AHA Brochures Your Heart Valve Surgery Your Mitral Valve Prolapse Innocent Heart Murmurs If Your Child Has a Congenital Heart Defect See all of our brochures Valve Disease Resources Patient Guide: Understanding Your Heart Valve Problem | ...

  19. FLUID MECHANICS OF ARTIFICIAL HEART VALVES

    OpenAIRE

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

    2009-01-01

    1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mecha...

  20. Options for Heart Valve Replacement

    Science.gov (United States)

    ... valve: Aortic regurgitation , (sometimes referred to as aortic insufficiency) is another common valve problem that may require ... allows oxygenated blood to flow backwards into the lungs instead of continuing through the heart as it ...

  1. How Is Heart Valve Disease Treated?

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  2. How Is Heart Valve Disease Diagnosed?

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  3. Antithrombotic Therapy in Patients with Prosthetic Heart Valves

    Directory of Open Access Journals (Sweden)

    Mohamed HA

    2009-01-01

    Full Text Available Patients with mechanical valve prostheses require a lifelong anticoagulant treatment. The combined use of Warfarin and low-dose aspirin appears to reduce the risk of valve thrombosis and systemic embolism at a low risk of bleeding. The management of women with prosthetic heart valves during pregnancy poses a particular challenge, as there are no available controlled clinical trials to provide guidelines for effective antithrombotic therapy. Oral anticoagulants, such as Warfarin, cause foetal embryopathy; unfractionated heparin and low-molecular-weight heparin have been reported to be ineffective in preventing thromboembolic complications.This article discusses the available data and the most recent guidelines in the antithrombotic management of patients with prosthetic valves, and antithrombotic therapy in various clinical situations such as pregnant women with prosthetic heart valves, and patients with prosthetic heart valves undergoing noncardiac surgery.

  4. 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

  5. Study on decellularized porcine aortic valve/poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) hybrid heart valve in sheep model.

    Science.gov (United States)

    Wu, Song; Liu, Ying-Long; Cui, Bin; Qu, Xiang-Hua; Chen, Guo-Qiang

    2007-09-01

    To overcome shortcomings of current heart valve prostheses, novel hybrid valves were fabricated from decellularized porcine aortic valves coated with poly (3-hydroxybutyrate-co-3-hydroxyhexanoate [PHBHHx]). In the mechanical test in vitro, the biomechanical performance of hybrid valve was investigated. In an in vivo study, hybrid valve conduits were implanted in pulmonary position in sheep without cardiopulmonary bypass. Uncoated grafts were used as control. The valves were explanted and examined histologically and biochemically 16 weeks after surgery. The hybrid valve conduits maintained original shapes, were covered by a confluent layer of cells, and had less calcification than uncoated control. The mechanical test in vitro revealed that PHBHHx coating improved tensile strength. The results in vivo indicated that PHBHHx coating reduced calcification and promoted the repopulation of hybrid valve with the recipient's cells resembling native valve tissue. The hybrid valve may provide superior valve replacement with current techniques.

  6. Pregnancy in women with prosthetic heart valves

    NARCIS (Netherlands)

    Pieper, P. G.; Balci, A.; Van Dijk, A. P.

    2008-01-01

    Pregnancy in women with mechanical valve prostheses has a high maternal complication rate including valve thrombosis mid death. Coumarin derivatives are relatively safe for the mother with a lower incidence of valve thrombosis than unfractionated and low-molecular-weight heparin, but carry the risk

  7. Pregnancy in women with prosthetic heart valves.

    NARCIS (Netherlands)

    Pieper, P.G.; Balci, A.; Dijk, A.P.J. van

    2008-01-01

    Pregnancy in women with mechanical valve prostheses has a high maternal complication rate including valve thrombosis and death. Coumarin derivatives are relatively safe for the mother with a lower incidence of valve thrombosis than un-fractionated and low-molecular-weight heparin, but carry the risk

  8. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    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 ...

  9. Emergency Heart Valve Replacement

    Science.gov (United States)

    Stinson, Edward B.; Shumway, Norman E.

    1968-01-01

    Sixteen patients with terminal cardiac failure due to valvular heart disease had emergency operation for value replacement. Four patients did not survive, because of irreversible myocardial or secondary organ involvement. The remainder, however, had immediate reversal of heart failure after operation, and all became fully active following discharge. Recognition of refractory decompensation in valvular heart disease demands prompt consideration of surgical intervention. PMID:5724875

  10. Injectable living marrow stromal cell-based autologous tissue engineered heart valves: first experiences with a one-step intervention in primates

    OpenAIRE

    Weber, B.; Scherman, J.; Emmert, M. Y.; Gruenenfelder, J.; Verbeek, R.; Bracher, M.; Black, M.; Kortsmit, J.; Franz, T.; Schoenauer, R.; Baumgartner, L.; Brokopp, C.; Agarkova, I.; Wolint, P.; Zund, G.

    2011-01-01

    Aims A living heart valve with regeneration capacity based on autologous cells and minimally invasive implantation technology would represent a substantial improvement upon contemporary heart valve prostheses. This study investigates the feasibility of injectable, marrow stromal cell-based, autologous, living tissue engineered heart valves (TEHV) generated and implanted in a one-step intervention in non-human primates. Methods and results Trileaflet heart valves were fabricated from non-woven...

  11. Tissue engineered aortic valve

    OpenAIRE

    Dohmen, P M

    2012-01-01

    Several prostheses are available to replace degenerative diseased aortic valves with unique advantages and disadvantages. Bioprotheses show excellent hemodynamic behavior and low risk of thromboembolic complications, but are limited by tissue deterioration. Mechanical heart valves have extended durability, but permanent anticoagulation is mandatory. Tissue engineering created a new generation heart valve, which overcome limitations of biological and mechanical heart valves due to remodelling,...

  12. Minimally Invasive Heart Valve Surgery.

    Science.gov (United States)

    Bouhout, Ismail; Morgant, Marie-Catherine; Bouchard, Denis

    2017-09-01

    Minimally invasive valve surgery represents a recent and significant advance in modern heart surgery. Indeed, many less invasive approaches for both the aortic and mitral valves have been developed in the past 2 decades. These procedures were hypothesized to result in less operative trauma, which might translate into better patient outcomes. However, this clinical benefit remains controversial in the literature. The aim of this review is to discuss the evidence surrounding minimally invasive heart valve surgery in the current era. A systematic search of the literature from 2006-2016 was performed looking for articles reporting early or late outcomes after minimally invasive valve surgery. Less invasive valve surgery is safe and provides long-term surgical outcomes similar to those of standard sternotomy. In addition, these approaches result in a reduction in overall hospital length of stay and may mitigate the risk of early morbidity-mainly postoperative bleeding, transfusions, and ventilation duration. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  13. Heart Valve Surgery Recovery and Follow Up

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Heart Valve Surgery Recovery and Follow Up Updated:Sep 14,2016 ... resources from Adam Pick's blog: Traveling Timeline After Heart Surgery 5 Things to Do While Your Heart Mends ( ...

  14. Patents and heart valve surgery--I: mechanical valves.

    Science.gov (United States)

    Cheema, Faisal H; Hussain, Nasir; Kossar, Alexander P; Polvani, Gianluca

    2013-04-01

    Valvular heart disease, inherited or acquired, affects more than 5 million Americans yearly. Whereas medical treatment is beneficial in the initial stages of valvular heart disease, surgical correction provides symptomatic relief and long-term survival benefits. Surgical options include either repair or replacement using mechanical or bio-prosthetic valves. Patient age and the post-operative need for anticoagulation therapy are major determinants of the choice between use of mechanical or bio-prosthetic valves. Since the first mechanical valves were made available several decades ago, the incorporation of increasingly sophisticated materials and methodologies has led to substantial improvements in the valve design, and has catalyzed a parallel increase in the amount of patents issued for these emerging technologies. In this paper, we have chronologically reviewed such patents, briefly discussed various challenges that mechanical heart valve implementation is faced with and finally reviewed some of the strategies employed to overcome such obstacles. An ideal prosthetic heart valve would comprehensively mimic the natural hemodynamics and physiology of the native heart valve. Additionally, such a valve would be easily implantable, associated with a minimal risk of thrombosis and thus need for anti-coagulation, and with a proven long-term durability. With cutting edge technological advancements in the recent times, the ongoing innovative and collaborative efforts of physicians, scientists, and engineers will not seize until an ideal mechanical heart valve becomes a reality.

  15. Quality of life after aortic valve replacement with biological prostheses in elderly patients

    Directory of Open Access Journals (Sweden)

    D. P. Demidov

    2017-11-01

    Full Text Available Aim. The paper aims to assess the quality of life of patients subjected to aortic valve replacement with a stented/stentless biological prosthesis. Methods. The research was done at the Acquired Heart Disease Department of Meshalkin National Medical Research Center. The inclusion criteria were patient age older than 65 years and severe stenosis of the aortic valve. 114 patients were randomized 1:1 in two groups: group I patients received stentless biological prostheses, while group II patients — stented xenopericardial ones. All patients underwent aortic valve replacement under normothermic cardiopulmonary bypass. Mean follow-up was 3.9 [2.77; 4.55] years, mean age 71.5±4 (65–84 years, mean left ventricle ejection fraction 65.5 (40–86 % and mean preoperative Log.Euroscore 5.4±1.3 (1.4–12.4. The quality of life was assessed by using a standard questionnaire SF-36.Results. Peak transprosthetic gradients at 1-year follow-up amounted to 16.22±4.34 and 24.66±4.74 mm Hg for group I and group II respectively. The 5-year survival rate was 90 [81; 99] % and 96 [90; 100] % for the two groups respectively and did not differ statistically (log rank test, p = 0.226. A statistically significant improvement of quality of life among patients in both groups was observed at 1-year follow-up, as compared to the preoperative values, however, marked intergroup differences in any of the parameters were not recorded.Conclusion. The quality of life after aortic valve replacement with stented and stentless biological prostheses in elderly patients confirms clinical and functional efficiency of both methods, does not show sound advantages of any of them and improves both the physical component of health and subjective emotional level.Received 25 July 2017. Revised 18 August 2017. Accepted 28 August 2017.Funding: The study was carried out with the support of a grant of the President of the Russian Federation (МД–6967.2016.7 created to provide government

  16. What Are the Signs and Symptoms of Heart Valve Disease?

    Science.gov (United States)

    ... as well as surgery for adults who have aortic valve stenosis. Doctors often use balloon valvuloplasty to repair valve stenosis in infants and children. Replacing Heart Valves Sometimes heart valves can’t ...

  17. EMT-inducing biomaterials for heart valve engineering: taking cues from developmental biology

    Science.gov (United States)

    Sewell-Loftin, M.K.; Chun, Young Wook; Khademhosseini, Ali; Merryman, W. David

    2012-01-01

    Although artificial prostheses for diseased heart valves have been around for several decades, viable heart valve replacements have yet to be developed due to their complicated nature. The majority of research in heart valve replacement technology seeks to improve decellularization techniques for porcine valves or bovine pericardium as an effort to improve current clinically used valves. The drawback of clinically used valves is that they are nonviable and thus do not grow or remodel once implanted inside patients. This is particularly detrimental for pediatric patients, who will likely need several reoperations over the course of their lifetimes to implant larger valves as the patient grows. Due to this limitation, additional biomaterials, both synthetic and natural in origin, are also being investigated as novel scaffolds for tissue engineered heart valves, specifically for the pediatric population. Here, we provide a brief overview of valves in clinical use as well as of the materials being investigated as novel tissue engineered heart valve scaffolds. Additionally, we focus on natural-based biomaterials for promoting cell behavior that is indicative of the developmental biology process that occurs in the formation of heart valves in utero, such as epithelial-to-mesenchymal transition or transformation (EMT). By engineering materials that promote native developmental biology cues and signaling, while also providing mechanical integrity once implanted, a viable tissue engineered heart valve may one day be realized. A viable tissue engineered heart valve, capable of growing and remodeling actively inside a patient, could reduce risks and complications associated with current valve replacement options and improve overall quality of life in the thousands of patients who received such valves each year, particularly for children. PMID:21751069

  18. In situ heart valve tissue engineering using a bioresorbable elastomeric implant - From material design to 12 months follow-up in sheep

    NARCIS (Netherlands)

    Kluin, Jolanda; Talacua, Hanna; Smits, Anthal I P M; Emmert, Maximilian Y; Brugmans, Marieke C P; Fioretta, Emanuela S; Dijkman, Petra E; Söntjens, Serge H M; Duijvelshoff, Renée; Dekker, Sylvia; Janssen-van den Broek, Marloes W J T; Lintas, Valentina; Vink, Aryan; Hoerstrup, Simon P; Janssen, Henk M; Dankers, Patricia Y W; Baaijens, Frank P T; Bouten, Carlijn V C

    2017-01-01

    The creation of a living heart valve is a much-wanted alternative for current valve prostheses that suffer from limited durability and thromboembolic complications. Current strategies to create such valves, however, require the use of cells for in vitro culture, or decellularized human- or

  19. Computed Tomography of Prosthetic Heart Valves

    NARCIS (Netherlands)

    Habets, J.

    2012-01-01

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

  20. 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....

  1. Metallurgical analysis of failed Björk-Shiley cardiac valve prostheses.

    Science.gov (United States)

    Sacks, S H; Harrison, M; Bischler, P J; Martin, J W; Watkins, J; Gunning, A

    1986-01-01

    An investigation into the mechanisms of failure of current Björk-Shiley cardiac valve prostheses is reported. Two failed valves, one apparently unfailed but defective valve, and one unused valve, were examined by scanning electron microscopy and metallographic section. In the first two valves (removed 12 and 23 months after implantation) fracture was associated with the welds joining the short strut to the valve ring. The fracture surfaces in all cases were heavily faceted and showed branching cracks. Extensive wear had occurred on one fracture surface in the first case, suggesting that one leg of the short strut had failed before the other, though this had been clinically undetectable. The third valve was removed owing to failure of the suturing (24 months after implantation) but one leg of the short strut was found to be completely fractured. The other leg showed extensive cracking and porosity in the weld region. A metallographic section taken through the weld region of the fourth (unused) valve illustrated several sizable defects directly attributable to the welding process. It is suggested that the valves failed by fatigue and that these problems could be overcome if the complete valve cage were machined as a single piece. Images PMID:3704981

  2. 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).

  3. [The Starr-Edwards heart valve: one of the oldest mechanical heart valves still functioning today].

    Science.gov (United States)

    Schoenaker, Michiel H; van Wetten, Herbert B; Morshuis, Wim J

    2015-01-01

    In the 1960s, the Starr-Edwards valve was the first artificial heart valve to be successfully implanted in humans. This valve has now been in use for decades with outstanding results: patients whose life expectancy had previously been short acquired a good prognosis with this development. Nowadays the Starr-Edwards valve is not used anymore, but patients are being described today in whom these valves are still functioning well after more than 40 years.

  4. Adherence of Staphylococcus aureus to Dyneema Purity® Patches and to Clinically Used Cardiovascular Prostheses

    NARCIS (Netherlands)

    Basir, Amir; Grundeman, Paul; Moll, Frans; van Herwaarden, Joost; Pasterkamp, Gerard; Nijland, Reindert

    2016-01-01

    Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for

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

    Science.gov (United States)

    Greiten, Lawrence E; McKellar, Stephen H; Rysavy, Joseph; Schaff, Hartzell V

    2014-05-01

    Warfarin is used to reduce the risk of stroke and thromboembolic complications in patients with mechanical heart valves. Yet, despite frequent blood testing, its poor pharmacokinetic and pharmacodynamic profiles often result in variable therapeutic levels. Rivaroxaban is a direct competitive factor Xa inhibitor that is taken orally. It inhibits the active site of factor Xa without the need for the cofactor antithrombin, and thus, its mechanism of action is differentiated from that of the fractionated heparins and indirect factor Xa inhibitors. No in vivo data exist regarding the effectiveness of rivaroxaban in preventing thromboembolic complications of mechanical heart valves. We tested the hypothesis that rivaroxaban is as effective as enoxaparin for thromboprophylaxis of mechanical valves that use a previously described heterotopic aortic valve porcine model. A modified bileaflet mechanical valved conduit that bypassed the native, ligated descending thoracic aorta was implanted into 30 swine. Postoperatively, the animals were randomly assigned to groups receiving no anticoagulation (n = 10), enoxaparin at 2 mg/kg subcutaneously twice daily (n = 10) or rivaroxaban at 2 mg/kg orally twice daily (n = 10). The amount of valve thrombus was measured on post-implantation day 30 as the primary end point. Quantitative evaluation of radiolabelled platelet deposition on the valve prostheses was done and embolic and haemorrhagic events were measured as secondary end points. Animals with no anticoagulation had a thrombus mean of 759.9 mg compared with 716.8 mg with enoxaparin treatment and 209.6 mg with rivaroxaban treatment (P = 0.05 for enoxaparin vs rivaroxaban). Similarly, the mean number of platelets deposited on the valve prosthesis was lower in the rivaroxaban group (6.13 × 10(9)) than in the enoxaparin group (3.03 × 10(10)) (P = 0.03). In this study, rivaroxaban was more effective than enoxaparin for short-term thromboprophylaxis of mechanical valve prosthetics in

  6. Pregnancy-induced remodeling of heart valves.

    Science.gov (United States)

    Pierlot, Caitlin M; Moeller, Andrew D; Lee, J Michael; Wells, Sarah M

    2015-11-01

    Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows. Leaflet structure was characterized by leaflet dimensions, and ECM composition was determined using standard biochemical assays. Histological studies assessed changes in cellular and ECM components. Leaflet mechanical properties were assessed using equibiaxial mechanical testing. Collagen thermal stability and cross-linking were assessed using denaturation and hydrothermal isometric tension tests. Pulmonary and tricuspid leaflet areas increased during pregnancy by 35 and 55%, respectively. Leaflet thickness increased by 20% only in the pulmonary valve and largely in the fibrosa (30% thickening). Collagen crimp length was reduced in both the tricuspid (61%) and pulmonary (42%) valves, with loss of crimped area in the pulmonary valve. Thermomechanics showed decreased collagen thermal stability with surprisingly maintained cross-link maturity. The pulmonary leaflet exhibited the biphasic change in extensibility seen in left side valves, whereas the tricuspid leaflet mechanics remained largely unchanged throughout pregnancy. The tricuspid valve exhibits a remodeling response during pregnancy that is significantly diminished from the other three valves. All valves of the heart remodel in pregnancy in a manner distinct from cardiac pathology, with much similarity valve to valve, but with interesting valve-specific responses in the aortic and tricuspid valves. Copyright © 2015 the American Physiological Society.

  7. Impact of aortic root geometry on hydrody-namic performance of transcatheter aortic valve prostheses

    Directory of Open Access Journals (Sweden)

    Kaule Sebastian

    2017-09-01

    Full Text Available Assessment of hydrodynamic performance of transcatheter aortic valve prostheses (TAVP in vitro is es-sentially in the fields of development and approval of novel implants. For the prediction of clinical performance, in vitro testing of TAVP allows for benchmarking of different devic-es, likewise. In addition to the implant itself, also the testing environment has a crucial influence on leaflet dynamics and quantitative test results like effective orifice area (EOA or aortic regurgitation.

  8. A Hybrid Tissue-Engineered Heart Valve

    National Research Council Canada - National Science Library

    Alavi, S Hamed; Kheradvar, Arash

    2015-01-01

    This study describes the efforts to develop and test the first hybrid tissue-engineered heart valve whose leaflets are composed of an extra-thin superelastic Nitinol mesh tightly enclosed by uniform...

  9. THE ROLE OF ANTICOAGULATION THERAPY IN PATIENTS WITH PROSTHETIC HEART VALVES

    Directory of Open Access Journals (Sweden)

    N. A. Shostak

    2016-01-01

    Full Text Available Cardiac surgery is the only radical method of treatment of valvular defects (congenital or acquired: valve preservation procedures or prosthetics operations. 250 000 – 280 000 valve prostheses are implanted every year worldwide, while the number of prosthetic valves operation increases by an average of 5–7 % per year (biological prostheses – 8–11 %, mechanical prostheses – 3–5 %. Selection of biological or mechanical types of prosthesis, its location, the presence of associated risk factors for embolic events, such as atrial fibrillation, previous embolism, left ventricular dysfunction, hypercoagulable states determine patient management tactics. Particularly high risk of prosthetic thrombosis and thromboembolic complications can be seen in case of mechanical prosthesis implantation. Numerous prospective and retrospective clinical studies have proven high effectiveness of anticoagulants for reduction the risk of cardioembolic complications. The degree of anticoagulation (optimal international normalized ratio (INR is determined by risk factors for prosthetic thrombosis and thromboembolic complications in a patient, as well as thrombogenicity of the prosthesis by itself; INR may range from 2.5 to 4.0. International recommendations take into account the presence/absence of additional risk factors for thromboembolism, and based on warfarin administration with the achievement of target INR values combined with low-dose aspirin. Administration of novel direct oral anticoagulation remedies in patients with prosthetic heart valves has not been studied sufficiently up to date and is contraindicated. Thus, warfarin currently is a drug of choice for the prevention of thromboembolic complications in patients with prosthetic heart valves.

  10. Renal Haemosiderosis in Patients with· Prosthetic Heart Valves ...

    African Journals Online (AJOL)

    The incidence of renal haemosiderosis was studied in 66 patients with valve prostheses, 32 patients with advanced rheumatic-type valvular deformities and in 21 consecutive routine adult autopsy cases. Significant renal haemosiderosis was present in 17 out of the 66 patients with prostheses. Mechanical factors may have ...

  11. Development of mechanical heart valves - an inspiring tale

    Directory of Open Access Journals (Sweden)

    P Rajashekar

    2015-01-01

    Full Text Available The historical evolution of the prosthetic heart valves from the first attempts with the Hufnagel′s valve in the treatment of the aortic insufficiency to the Starr-Edwards′ ball valve and later the tilting disc valves (Bjork-Shiley etc., and finally the bileaflet valves (St. Jude are discussed. The Indian contribution with Chitra valve is also described.

  12. [Heart valve prosthesis and pregnancy].

    Science.gov (United States)

    Ben-Ismail, M; Fekih, M; Taktak, M; Chelli, M

    1979-02-01

    Sixteen pregnancies were followed up in 13 patients with prosthetic heart valves: 8 pregnancies went to term under oral anticoagulation, 4 under heparin and 4 without anticoagulation. 9 healthy normal children were delivered; there were 2 still births and 5 abortions. On the maternal side 3 haemorrhages and thromboembolic episodes which involved 2 patients on heparin, one of whom died, were observed. The following points are apparent from our observations and a review of the existing medical literature: --the risk of thromboembolism is not increased. The marked clotting tendency of maternal blood post-partum contraindicates the withdrawal of anticoagulants during this critical period; --haemorrhagic complications are common with anticoagulants; --foetal loss is greatly increased; --the teratogenecity of vitamin-K antagonists is certain, but the risk is small. The problems of anticoagulation are discussed; theoretically heparin should be given during the 1st trimestre and from the 38th week to the second post-partum week. The patients should be closely supervised by both obstetrician and cardiologist and hospitalisation is advised for the last month of pregnancy. Normal vaginal delivery is usually possible.

  13. Recognizing the Symptoms of Worsening Heart Valve Disease

    Science.gov (United States)

    ... be hard to separate our habits from the mechanics of our hearts, which is one important reason ... About Heart ValvesHeart Valve Problems and Causes • Risks, Signs and Symptoms Introduction Understanding Symptoms Recognizing Symptoms ...

  14. Echocardiographic assessment of long-term hemodynamic characteristics of mechanical mitral valve prostheses with different mitral valvular diseases.

    Science.gov (United States)

    Zhu, Xiliang; Li, Qian; Tang, Hong; Xiao, Xijun

    2017-03-01

    Mitral stenosis (MS) and mitral insufficiency (MI) have different pre-operative hemodynamic characteristics. However, it is unclear if there are differences in long-term echocardiographic characteristics of MS and MI patients after mechanical mitral valve replacement. This study is to compare long-term echocardiographic results of mechanical mitral valve prostheses between MS and MI patients. From January 2003 to January 2009, a total of 199 consecutive patients were recruited in this study. Patients were classified as group MS (n = 123) and MI (n = 76) according to the manifestation of mitral valvular disease. The mean age for patients was 50.1 ± 10.5 years and follow-up time was 7.2 ± 2.0 years. The MS after operation were more likely to experience atrial fibrillation (p = 0.002). The New York Heart Association (NYHA) class in MI showed a greater improvement (p = 0.006) than in MS. The left ventricular end-diastolic dimension (LVEDD) (p = 0.010) and stroke volume (SV) (p = 0.000) in MI were still larger than that in MS patients. These differences did not disappear with time after operation. The long-term echocardiographic results of mechanical mitral valve prostheses between MS and MI patients are significantly different. Over a long-term follow up, MI patients still have a larger LVEDD and SV than MS, and associated with a greater improvement of NYHA class.

  15. A Hybrid Tissue-Engineered Heart Valve.

    Science.gov (United States)

    Alavi, S Hamed; Kheradvar, Arash

    2015-06-01

    This study describes the efforts to develop and test the first hybrid tissue-engineered heart valve whose leaflets are composed of an extra-thin superelastic Nitinol mesh tightly enclosed by uniform tissue layers composed of multiple cell types. The trileaflet Nitinol mesh scaffolds underwent three-dimensional cell culture with smooth muscle and fibroblast/myofibroblast cells enclosing the mesh, which were finally covered by an endothelial cell layer. Quantitative and qualitative assays were performed to analyze the microstructure of the tissues. A tissue composition almost similar to that of natural heart valve leaflets was observed. The function of the valves and their Nitinol scaffolds were tested in a heart flow simulator that confirmed the trileaflet valves open and close robustly under physiologic flow conditions with an effective orifice area of 75%. The tissue-metal attachment of the leaflets once exposed to physiologic flow rates was tested and approved. Our preliminary results indicate that the novel hybrid approach with nondegradable scaffold for engineering heart valves is viable and may address the issues associated with current tissue-engineered valves developed with degradable scaffolds. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  16. Experimental study of asymmetric heart valve prototype

    Science.gov (United States)

    Vukicevic, M.; Fortini, S.; Querzoli, G.; Cenedese, A.; Pedrizzetti, G.

    2011-11-01

    The mechanical heart valves (MHVs) are extremely important medical devices, commonly used for diseased heart valves replacement. Despite the long term of use and constant design refinement, the MHVs are very far from ideal and their performance is very diverse from that of the native ones. It has been approved that small variations in geometry of valvular leaflets influence the significant change in the intraventricular vortical flow, known as one of the most important factors for the overall functionality of the heart. We have experimentally examined the home-made heart valve prototypes, exclusively modeled for the mitral valve replacement. The performance and energetic properties of the prototypes have been compared with those in the presence of standard MHVs. The analysis was based on the testing of intraventricular fluid dynamics, usually missing criteria for the quality of the valve performance. It has been shown that the asymmetric prototype, with unequal leaflets and D-shaped orifice produces flow patterns and energetic properties close to those found in the healthy subjects. Thus, the break of symmetry in the standard bi-leaflet MHV prosthesis, at least from the fluid dynamics point of view, is worthwhile to be considered for the design of MHVs for the mitral valve replacement.

  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 (mechanism found to be a possible contributor to these adverse effects is cavitation. In vitro, cavitation has been directly demonstrated by visualization and indirectly in vivo by registering of high frequency pressure fluctuations (HFPF). Tilting disc 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.

  18. Aortic Calcification: An Early Sign of Heart Valve Problems?

    Science.gov (United States)

    ... the aortic valve — a condition called aortic valve stenosis. Aortic valve calcification may be an early sign ... have any other heart disease symptoms. Calcification and stenosis generally affects people older than age 65. When ...

  19. Structural valve deterioration in the Mitroflow biological heart valve prosthesis

    DEFF Research Database (Denmark)

    Issa, Issa Farah; Poulsen, Steen Hvitfeldt; Waziri, Farhad

    2018-01-01

    OBJECTIVES: Concern has been raised regarding the long-term durability of the Mitroflow biological heart valve prosthesis. Our aim was to assess the incidence of structural valve degeneration (SVD) for the Mitroflow bioprosthesis in a nationwide study in Denmark including all patients alive...... in Denmark who had received a Mitroflow aortic bioprosthesis since 2000. METHODS: Patients alive in Denmark with a Mitroflow bioprosthesis implanted since January 2000 were invited to participate in a nationwide cross-sectional study with a predefined definition of SVD. Of 1552 patients, 861 patients had...

  20. Cardiac Rehabilitation After Heart Valve Surgery

    DEFF Research Database (Denmark)

    Pollmann, Agathe Gerwina Elena; Frederiksen, Marianne; Prescott, Eva

    2017-01-01

    PURPOSE: Evidence of the effect of cardiac rehabilitation (CR) after heart valve surgery is scarce, but nevertheless CR is recommended for this group of patients. Therefore, this study assessed the effect of CR on exercise capacity, cardiovascular risk factors, and long-term mortality and morbidity......, as well as predictors for enrolment in or failing to complete CR. METHODS: A review of medical records identified 250 patients who underwent heart valve surgery between January 2009 and August 2013. Of these, 211 patients eligible for CR were identified. Effect of CR was assessed by peak oxygen uptake.......58-15.06). CONCLUSIONS: CR after heart valve surgery improved exercise capacity and was associated with reduced morbidity. Elderly and ethnic minorities were less likely to attend or complete CR and deserve special attention....

  1. Rotational angiography with motion compensation: first-in-man use for the 3D evaluation of transcatheter valve prostheses.

    Science.gov (United States)

    Schultz, Carl J; Lauritsch, Guenter; Van Mieghem, Nicholas; Rohkohl, Christopher; Serruys, Patrick W; van Geuns, Robert Jan; de Jaegere, Peter P T

    2015-08-01

    We evaluated a novel motion-compensating 3D reconstruction technique applied to rotational angiography (R-angio) which produces MSCT-like images for evaluation of implanted TAVI prostheses without requiring rapid pacing. Fifty-one consecutive patients were retrospectively identified who were evaluated with rotational angiography (R-angio) using the Siemens Artis zee angiographic C-arm system after TAVI with a Medtronic CoreValve prosthesis. A novel 3D image reconstruction technique was applied which corrects for cardiac motion. CoreValve frame geometry was evaluated according to the same protocol for MSCT and R-angio at the level of: 1) the inflow, 2) the nadirs, 3) central coaptation, and 4) the commissures. The native aortic annulus dimensions were measured at the nadirs of the three leaflets. Sizing ratio, prosthesis expansion and frame ellipticity were assessed. Good quality 3D reconstructions were obtained in 43 patients (84%) and failure was predictable prior to reconstruction in six of the other seven patients (superposition of radiographically dense object n=4, obesity n=2). Prosthesis inflow ellipticity and expansion were correlated with implantation depth (respectively r=-0.46, pprosthesis ellipticity at the level of central coaptation (median [25th-75th percentile]: 1.15 [1.10-1.20] vs. 1.08 [1.06-1.12], p=0.009). The inter-observer, inter-modality (MSCT, R-angio) variability in measurement at the level of coaptation for minimum diameter, maximum diameter and area were all low (respectively, mean ±SD:1.2% ±1.2; 1.7% ±1.8 and 2.0% ±1.3). R-angio with motion-compensated reconstruction offers new possibilities for evaluation of the post-implantation geometry of percutaneous structural heart prostheses and the potential clinical effects.

  2. 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.

  3. 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

    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.......4%–2.9%) for the control group. Conclusion: Self-management of OAT is a feasible and safe concept for selected patients with mechanical heart valve prostheses also on a long-term basis. It provides at least as good and most likely better quality of anticoagulant therapy than conventional management assessed by time within...... 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...

  4. Transient pressure signals in mechanical heart valve cavitation.

    Science.gov (United States)

    Wu, Z J; Slonin, J H; Hwang, N H

    1996-01-01

    The purpose of this investigation was to establish a correlation between mechanical heart valve (MHV) cavitation and transient pressure (TP) signals at MHV closure. This correlation may suggest a possible method to detect in vivo MHV cavitation. In a pulsatile mock flow loop, a study was performed to measure TP and observe cavitation bubble inception at MHV closure under simulated physiologic ventricular and aortic pressures at heart rates of 70, 90, 120, and 140 beats/min with corresponding cardiac outputs of 5.0, 6.0, 7.5, and 8.5 L/min, respectively. The experimental study included two bileaflet MHV prostheses: 1) St. Jude Medical 31 mm and 2) Carbomedics 31 mm. High fidelity piezo-electric pressure transducers were used to measure TP immediately before and after the valve leaflet/housing impact. A stroboscopic lighting imaging technique was developed to capture cavitation bubbles on the MHV inflow surfaces at selected time delays ranging from 25 microseconds to 1 ms after the leaflet/housing impact. The TP traces measured 10 mm away from the valve leaflet tip showed a large pressure reduction peak at the leaflet/housing impact, and subsequent high frequency pressure oscillations (HPOs) while the cavitation bubbles were observed. The occurrence of cavitation bubbles and HPO bursts were found to be random on a beat by beat basis. However, the amplitude of the TP reduction, the intensity of the cavitation bubble (size and number), and the intensity of HPO were found to increase with the test heart rate. A correlation between the MHV cavitation bubbles and the HPO burst was positively established. Power spectrum analysis of the TP signals further showed that the frequency of the HPO (cavitation bubble collapse pressures) ranged from 100 to 450 kHz.

  5. What Is Heart Valve Surgery?

    Science.gov (United States)

    ... called stenosis). • Don’t close properly and let blood leak where it shouldn’t. This is called incompetence, insufficiency or regurgitation. • Prolapse — mitral valve flaps don’t close properly (more common in women).As pressure builds inside the left ventricle, it pushes the ...

  6. Autologous valve replacement-CD133+ stem cell-plus-fibrin composite-based sprayed cell seeding for intraoperative heart valve tissue engineering.

    Science.gov (United States)

    Kaminski, Alexander; Klopsch, Christian; Mark, Peter; Yerebakan, Can; Donndorf, Peter; Gäbel, Ralf; Eisert, Friederike; Hasken, Stefan; Kreitz, Sebastian; Glass, Aenne; Jockenhövel, Stefan; Ma, Nan; Kundt, Guenther; Liebold, Andreas; Steinhoff, Gustav

    2011-03-01

    The development of biological valve prostheses with lifetime native-like performance and optimal host engraftment is an ultimate goal of heart valve tissue engineering. We describe a new concept for autologous graft coating based on a CD133(+)-stem-cells-plus-fibrin (SC+F) complex processed from bone marrow and peripheral blood of a single patient. CD133(+)-SC (1 × 10(6) cells/mL) from human bone marrow and autologous fibrin (20 mg/mL) were administered simultaneously via spray administration using the novel Vivostat Co-Delivery System. During static cultivation, SC+F performance was monitored for 20 days after delivery and compared with controls. For dynamic testing SC+F-composite was sprayed on a decellularized porcine pulmonary valve and transferred to a bioreactor under pulsatile flow conditions for 7 days. Static cultivation of SC+F-composite induced significant improvements in stem cell proliferation as compared with controls. For dynamic testing, microscopic analyses on a smooth engineered heart valve surface detected homogenous distribution of stem cells. Ultrasonic analysis revealed native-like valve performance. Applied CD133(+) stem cells differentiated into endothelial-like cells positive for CD31 and vascular endothelial growth factor receptor 2 and engrafted the valve. However, occasional delamination was observed. SC+F serves as an excellent autologous matrix for intraoperative tissue engineering of valve prostheses promising optimal in vivo integration. However, stability remains an issue.

  7. Assessment of trans-aortic pressure gradient using a coronary pressure wire in patients with mechanical aortic and mitral valve prostheses.

    Science.gov (United States)

    Kherada, Nisharahmed; Brenes, Juan Carlos; Kini, Annapoorna S; Dangas, George D

    2017-03-15

    Accurate evaluation of trans-aortic valvular pressure gradients is challenging in cases where dual mechanical aortic and mitral valve prostheses are present. Non-invasive Doppler echocardiographic imaging has its limitations due to multiple geometric assumptions. Invasive measurement of trans-valvular gradients with cardiac catheterization can provide further information in patients with two mechanical valves, where simultaneous pressure measurements in the left ventricle and ascending aorta must be obtained. Obtaining access to the left ventricle via the mitral valve after a trans-septal puncture is not feasible in the case of a concomitant mechanical mitral valve, whereas left ventricular apical puncture technique is associated with high procedural risks. Retrograde crossing of a bileaflet mechanical aortic prosthesis with standard catheters is associated with the risk of catheter entrapment and acute valvular regurgitation. In these cases, the assessment of trans-valvular gradients using a 0.014˝ diameter coronary pressure wire technique has been described in a few case reports. We present the case of a 76-year-old female with rheumatic valvular heart disease who underwent mechanical aortic and mitral valve replacement in the past. She presented with decompensated heart failure and echocardiographic findings suggestive of elevated pressure gradient across the mechanical aortic valve prosthesis. The use of a high-fidelity 0.014˝ diameter coronary pressure guidewire resulted in the detection of a normal trans-valvular pressure gradient across the mechanical aortic valve. This avoided a high-risk third redo valve surgery in our patient. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  8. In vitro evaluation of implantation depth in valve-in-valve using different transcatheter heart valves.

    Science.gov (United States)

    Simonato, Matheus; Azadani, Ali N; Webb, John; Leipsic, Jonathon; Kornowski, Ran; Vahanian, Alec; Wood, David; Piazza, Nicolo; Kodali, Susheel; Ye, Jian; Whisenant, Brian; Gaia, Diego; Aziz, Mina; Pasala, Tilak; Mehilli, Julinda; Wijeysundera, Harindra C; Tchetche, Didier; Moat, Neil; Teles, Rui; Petronio, Anna Sonia; Hildick-Smith, David; Landes, Uri; Windecker, Stephan; Arbel, Yaron; Mendiz, Oscar; Makkar, Raj; Tseng, Elaine; Dvir, Danny

    2016-09-18

    Transcatheter heart valve (THV) implantation in failed bioprosthetic valves (valve-in-valve [ViV]) offers an alternative therapy for high-risk patients. Elevated post-procedural gradients are a significant limitation of aortic ViV. Our objective was to assess the relationship between depth of implantation and haemodynamics. Commercially available THVs used for ViV were included in the analysis (CoreValve Evolut, SAPIEN XT and the Portico valve). THVs were implanted in small surgical valves (label size 19 mm) to simulate boundary conditions. Custom-mounted pulse duplicators registered relevant haemodynamic parameters. Twenty-eight experiments were performed (13 CVE, 5 SXT and 10 Portico). Ranges of depth of implantation were: CVE: -1.2 mm to 15.7 mm; SXT: -2.2 mm to 7.5 mm; Portico: 1.4 mm to 12.1 mm. Polynomial regression established a relationship between depth of implantation and valvular mean gradients (CVE: p<0.001; SXT: p=0.01; Portico: p=0.002), as well as with EOA (CVE: p<0.001; SXT: p=0.02; Portico valve: p=0.003). In addition, leaflet coaptation was better in the high implantation experiments for all valves. The current comprehensive bench testing assessment demonstrates the importance of high device position for the attainment of optimal haemodynamics during aortic ViV procedures.

  9. High readmission rate after heart valve surgery

    DEFF Research Database (Denmark)

    Sibilitz, K L; Berg, S K; Thygesen, Lau Caspar

    2015-01-01

    age (hazard ratio (95% CI): 1.3 (1.0-1.6)), male sex (1.2 (1.0-1.5)), mitral valve surgery (1.3 (1.0-1.6)), and infective endocarditis after surgery (1.8 (1.1-3.0), p: 0.01) predicted readmission, whereas higher age (2.3 (1.0-5.4)), higher comorbidity score (3.2 (1.8-6.0)), and infective endocarditis......BACKGROUND: After heart valve surgery, knowledge on long-term self-reported health status and readmission is lacking. Thus, the optimal strategy for out-patient management after surgery remains unclear. METHODS: Using a nationwide survey with linkage to Danish registers with one year follow-up, we...... included all adults 6-12 months after heart valve surgery irrespective of valve procedure, during Jan-June 2011 (n = 867). Participants completed a questionnaire regarding health-status (n = 742), and answers were compared with age- and sex-matched healthy controls. Readmission rates and mortality were...

  10. Sutureless replacement of aortic valves with St Jude Medical mechanical valve prostheses and Nitinol attachment rings: feasibility in long-term (90-day) pig experiments.

    Science.gov (United States)

    Berreklouw, Eric; Koene, Bart; De Somer, Filip; Bouchez, Stefaan; Chiers, Koen; Taeymans, Yves; Van Nooten, Guido J

    2011-05-01

    Nitinol attachment rings (devices) used to attach mechanical aortic valve prostheses suturelessly were studied in long-term (90 days) pig experiments. The aortic valve was removed and replaced by a device around a St Jude Medical mechanical valve prosthesis in 10 surviving pigs. Supravalvular angiography was done at the end of the operation. No coumarin derivates were given. No or minimal aortic regurgitation was confirmed in all surviving pigs at the end of the operation. Total follow-up was 846 days. In 4 pigs, follow-up was shorter than 90 days (28-75 days); the other 6 pigs did reach 90 days' survival or more. Repeat angiography in 4 pigs at the end of follow-up confirmed the unchanged position of the device at the aortic annulus, without aortic regurgitation. At autopsy, in all pigs the devices proved to be well grown in at the annulus, covered with endothelium, and sometimes tissue overgrowth related to not using coumarin derivates. There was no case of para-device leakage, migration, or embolization. No damage to surrounding anatomic structures or prosthetic valves was found. Nitinol attachment rings can be used to replace the aortic valve suturelessly with St Jude Medical mechanical aortic valve prostheses, without para-device leakage, migration, or damage to the surrounding tissues, in long-term pig experiments during a follow-up of 90 days or more. Refraining from anticoagulation in pigs with mechanical valve prostheses can lead to tissue overgrowth of the valve prosthesis. Further studies are needed to determine long-term feasibility of this method in human beings. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  11. Long-Term Clinical Outcomes of Silzone Era St. Jude Medical Mechanical Heart Valves.

    Science.gov (United States)

    Brennan, J Matthew; Zhao, Yue; Williams, Judson; O'Brien, Sean; Dokholyan, Rachel; Gammie, James; Edwards, Fred; Loyo-Berrios, Nilsa; Canos, Daniel; Gross, Thomas; Marinac-Dabic, Danica; Peterson, Eric

    2015-01-01

    Since the voluntary recall of St. Jude Medical (SJM) Silzone impregnated heart valves, no large-scale study has examined their long-term outcomes. Using Medicare-linked records from the Society of Thoracic Surgeons Adult Cardiac Surgery Database (1993-2004), the clinical outcomes were evaluated through eight years among those patients who received SJM mechanical heart valves during the Silzone era (March 1998 to December 1999; n = 3,775), relative to those in both the pre-Silzone era (January 1993 to February 1998; n = 13,570) and the post-Silzone era (January 2000 to December 2004; n = 6,882). An inverse probability weighting was used to balance the observed differences in case mix. During the Silzone era, 79% of all implanted mechanical heart valves were manufactured by SJM. By eight years post-implantation, the most common adverse events in this Medicare-linked cohort (median age 71 years) were death (43.5%) and thromboembolism (14.7%), while valve reoperation (1.7%) and endocarditis (1.4%) were less common. Patients treated during the Silzone era experienced a lower associated risk of mortality to eight years than those in both the pre-Silzone era (adjusted hazards ratio (HR) 0.93, 95% confidence interval (CI) 0.88-0.98) and post-Silzone era (adjusted HR 0.92, CI 0.67-0.98), while the adjusted eight-year risks of reoperation, thromboembolism and endocarditis were similar across the three eras for the overall cohort and among both aortic valve and mitral valve patients. Medicare patients who received SJM mechanical heart valves during the Silzone era experienced similar clinical outcomes as those treated before or after the Silzone era. These data do not substantiate continued public health concerns associated with Silzone era valve prostheses among older individuals.

  12. 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

    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)....

  13. Effect of Fluid Viscosity on Noise of Bileaflet Prosthetic Heart Valve

    Directory of Open Access Journals (Sweden)

    Vladimir A. Voskoboinick

    2017-10-01

    Full Text Available Background. Numerical simulation and experimental research have been used as powerful tools to understand and predict the behavior and mechanics of the operation of natural heart valves and their prostheses in natural and patho­logical conditions. Such studies help to evaluate the effectiveness of the valves, their design and the results of surgical procedures, to diagnose healthy and impaired function of the heart valves. There is an actual problem in creating more reliable methods and tools for the operation diagnostics of mechanical heart valves. Objective. The aim of the research is to investigate the effect of fluid viscosity on the hydroacoustic characteristics of jets that flow from a semi-closed and open mechanical bileaflet heart valve. To study the possibility of using hydro­acoustic measuring instruments as diagnostic equipment for determining the working conditions of the bileaflet pro­sthe­tic heart valve. Methods. The experimental research was carried out by means of hydroacoustic measurements of the hydrodynamic noise in the near wake of the side and central jets of the glycerin solution and the pure water flow downstream of the prosthetic bileaflet heart valve. Results. The effect of fluid viscosity on the hydroacoustic characteristics of the jets that flow from a semi-closed and open mechanical bileaflet heart valve has been experimentally determined. Integral and spectral characteristics of the hydrodynamic noise of jets of the glycerin solution and the pure water flow downstream of the bileaflet mitral heart valve for different fluid rate were detected. Conclusions. In the stream conditions of pure water, the integral characteristics of the pressure field are lower than in stream conditions of the aqueous glycerin solution. As the glycerin concentration in the solution increases, increase average pressures and especially RMS pressure fluctuations. The spectral levels of the hydrodynamic noise in the near wake of the side

  14. Valve Replacement with the Starr-Edwards and Hancock Prostheses: Comparative Analysis of Late Morbidity and Mortality

    Science.gov (United States)

    Oyer, Philip E.; Stinson, Edward B.; Griepp, Randall B.; Shumway, Norman E.

    1977-01-01

    Although the Starr-Edwards caged-ball valve remains a standard of comparison for more recently introduced prostheses, a substantial incidence of thromboembolic and hemorrhagic complications prompted our evaluation of the Hancock glutaraldehyde-fixed porcine xenograft. We have compared the results of 435 aortic valve replacements using the Starr- Edwards valve (SE-AVR), 515 mitral valve replacements (SE-MVR), and 121 double-valve replacements (SE-AVRMVR) with 251 aortic valve replacements using the xenograft aortic valve (X-AVR), 338 mitral valve replacements (X-MVR), and 88 double-valve replacements (X-AVR-MVR). The Starr- Edwards valves were used during the period 1963 through 1973 and the xenograft valves between 1971 and 1976. No significant differences in patient age, sex, or preoperative hemodynamic data were noted between comparable groups. All patients with Starr-Edwards valves received long-term anticoagulation while anticoagulants were used only for specific indications in patients with xenograft valves. Total follow up was 3944 patient years for the Starr-Edwards patients and 947 patient years for the xenograft patients. Hospital mortality was not significantly different for comparable groups: SE-AVR 6.9% vs. X-AVR 6.4%, SE-MVR 9.7% vs X-MVR 8.6%, and SE-AVR-MVR 7.5% vs. X-AVR-MVR 10.2%. Linearized mortality and morbidity data expressed as percent per patient- year are tabulated below. Pairs which differ significantly (p < .05) are italicized. PMID:560824

  15. The Bundle of His in Prosthetic Heart Valve Replacement*

    African Journals Online (AJOL)

    1973-01-27

    Jan 27, 1973 ... sudden deaths which occur following heart valve replace- ment. In our local cardiac surgery unit at Groote Schuur. Hospital, the hospital mortality rate for aortic valve replacement with the University of Cape Town (VeT) aortic valve prosthesis between March 1963 and October. 1968, was 120. 0 according to ...

  16. Cardiac crossroads: deciding between mechanical or bioprosthetic heart valve replacement

    Directory of Open Access Journals (Sweden)

    Maggie N Tillquist

    2011-02-01

    Full Text Available Maggie N Tillquist1, Thomas M Maddox21School of Medicine, University of Colorado Denver, Denver, CO, USA; 2VA Eastern Colorado Health Care System, and Department of Medicine (Cardiology, University of Colorado Denver, Denver, CO, USAAbstract: Nearly 15 million people in the United States suffer from either aortic or mitral valvular disease. For patients with severe and symptomatic valvular heart disease, valve replacement surgery improves morbidity and mortality outcomes. In 2009, 90,000 valve replacement surgeries were performed in the United States. This review evaluates the advantages and disadvantages of mechanical and bioprosthetic prosthetic heart valves as well as the factors for consideration in deciding the appropriate valve type for an individual patient. Although many caveats exist, the general recommendation is for patients younger than 60 to 65 years to receive mechanical valves due to the valve's longer durability and for patients older than 60 to 65 years to receive a bioprosthetic valve to avoid complications with anticoagulants. Situations that warrant special consideration include patient co-morbidities, the need for anticoagulation, and the potential for pregnancy. Once these characteristics have been considered, patients' values, anxieties, and expectations for their lifestyle and quality of life should be incorporated into final valve selection. Decision aids can be useful in integrating preferences in the valve decision. Finally, future directions in valve technology, anticoagulation, and medical decision-making are discussed.Keywords: prosthetic heart valves, patient preference, valve type, anticoagulant, structural valve deterioration 

  17. Serotonin Mechanisms in Heart Valve Disease I

    Science.gov (United States)

    Jian, Bo; Xu, Jie; Connolly, Jeanne; Savani, Rashmin C.; Narula, Navneet; Liang, Bruce; Levy, Robert J.

    2002-01-01

    Clinical disorders associated with increased serotonin [5-hydroxytryptamine (5-HT)] levels, such as carcinoid syndrome, and the use of serotonin agonists, such as fenfluoramine have been associated with a valvulopathy characterized by hyperplastic valvular and endocardial lesions with increased extracellular matrix. Furthermore, 5-HT has been demonstrated to up-regulate transforming growth factor (TGF)-β in mesangial cells via G-protein signal transduction. We investigated the hypothesis that increased exposure of heart valve interstitial cells to 5-HT may result in increased TGF-β1 expression and activity because of serotonin receptor-mediated signal transduction with activation of Gαq, and subsequently up-regulation of phospholipase C. Thus, in the present study we performed a clinical-pathological investigation of retrieved carcinoid and normal valve cusps using immunohistochemical techniques to detect the presence of TGF-β1 and other proteins associated with TGF-β expression, including TGF-β receptors I and II, latent TGF-β-associated peptide (LAP), and α-smooth muscle actin. Carcinoid valve cusps demonstrated the unusual finding of widespread smooth muscle actin involving the interstitial cells in the periphery of carcinoid nodules; these same cells were also positive for LAP. Normal valve cusps were only focally positive for smooth muscle actin and LAP. In sheep aortic valve interstitial cell cultures 5-HT induced TGF-β1 mRNA production and increased TGF-β1 activity. 5-HT also increased collagen biosynthesis at the dosages studied. Furthermore, TGF-β1 added to SAVIC cultures increased the production of sulfated glycan and hyaluronic acid. In addition, overexpression of Gαq using an adenoviral expression vector for a constitutively active Gαq mutant (Q209L-Gαq) resulted in increased phospholipase C activity as well as up-regulation of TGF-β expression and activity. These results strongly support the view that G-protein-related signal

  18. Partitioning the heart: mechanisms of cardiac septation and valve development

    OpenAIRE

    Lin, Chien-Jung; Lin, Chieh-Yu; Chen, Chen-Hao; Zhou, Bin; Chang, Ching-Pin

    2012-01-01

    Heart malformations are common congenital defects in humans. Many congenital heart defects involve anomalies in cardiac septation or valve development, and understanding the developmental mechanisms that underlie the formation of cardiac septal and valvular tissues thus has important implications for the diagnosis, prevention and treatment of congenital heart disease. The development of heart septa and valves involves multiple types of progenitor cells that arise either within or outside the ...

  19. 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.

  20. Weaving for heart valve tissue engineering.

    Science.gov (United States)

    Liberski, Albert; Ayad, Nadia; Wojciechowska, Dorota; Kot, Radoslaw; Vo, Duy M P; Aibibu, Dilibaier; Hoffmann, Gerald; Cherif, Chokri; Grobelny-Mayer, Katharina; Snycerski, Marek; Goldmann, Helmut

    2017-11-01

    Weaving is a resourceful technology which offers a large selection of solutions that are readily adaptable for tissue engineering (TE) of artificial heart valves (HV). The different ways that the yarns are interlaced in this technique could be used to produce complex architectures, such as the three-layer architecture of the leaflets. Once the assembly is complete, growth of cells in the scaffold would occur in the orientation of the yarn, enabling the deposition of extra cellular matrixes proteins in an oriented manner. Weaving technology is a rapidly evolving field that, first, needs to be understood, and then explored by tissue engineers, so that it could be used to create efficient scaffolds. Similarly, the textile engineers need to gain a basic understanding of key structural and mechanical aspects of the heart valve. The aim of this review is to provide the platform for joining these two fields and to enable cooperative research efforts. Moreover, examples of woven medical products and patents as well as related publication are discussed in this review, nevertheless due to the large, and continuously growing volume of data, only the aspects strictly associated with HVTE lay in the scope of this paper. Copyright © 2017 Elsevier Inc. All rights reserved.

  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...

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

    Science.gov (United States)

    Amstrup Funder, Jonas; Christian Danielsen, Carl; Baandrup, Ulrik; Martin Bibby, Bo; Carl Andelius, Ted; Toft Brøndum, Emil; Wang, Tobias; Michael Hasenkam, J

    2017-01-01

    Heart valves which exist naturally in an extreme-pressure system must have evolved in a way to resist the stresses of high pressure. Giraffes are interesting as they naturally have a blood pressure twice that of humans. Thus, knowledge regarding giraffe heart valves may aid in developing techniques to design improved pressure-resistant biological heart valves. Heart valves from 12 giraffes and 10 calves were explanted and subjected to either biomechanical or morphological examinations. Strips from the heart valves were subjected to cyclic loading tests, followed by failure tests. Thickness measurements and analyses of elastin and collagen content were also made. Valve specimens were stained with hematoxylin and eosin, elastic van Gieson stain, Masson's trichrome and Fraser-Lendrum stain, as well as immunohistochemical reactions for morphological examinations. The aortic valve was shown to be 70% (95% CI 42-103%) stronger in the giraffe than in its bovine counterpart (p giraffe aortic valve was found to be significantly stiffer than the bovine aortic valve (p giraffes contained significantly more collagen than those of calves. The elastin contents of the pulmonary valves (2.5%) and aortic valves (1.5%) were also higher in giraffes. The greater strength of the giraffe aortic valve is most likely due to a compact collagen construction. Both, collagen and elastin contents were higher in giraffes than in calves, which would make giraffe valves more resistant to the high-pressure forces. However, collagen also stiffens and thickens the valves. The mitral leaflets showed similar (but mostly insignificant) trends in strength, stiffness, and collagen content.

  3. Experimental investigations on the fluid-mechanics of an electrospun heart valve by means of particle image velocimetry.

    Science.gov (United States)

    Del Gaudio, Costantino; Gasbarroni, Pier Luca; Romano, Giovanni Paolo

    2016-12-01

    End-stage failing heart valves are currently replaced by mechanical or biological prostheses. Both types positively contribute to restore the physiological function of native valves, but a number of drawbacks limits the expected performances. In order to improve the outcome, tissue engineering can offer an alternative approach to design and fabricate innovative heart valves capable to support the requested function and to promote the formation of a novel, viable and correctly operating physiological structure. This potential result is particularly critical if referred to the aortic valve, being the one mainly exposed to structural and functional degeneration. In this regard, the here proposed study presents the fabrication and in vitro characterization of a bioresorbable electrospun heart valve prosthesis using the particle image velocimetry technique either in physiological and pathological fluid dynamic conditions. The scaffold was designed to reproduce the aortic valve geometry, also mimicking the fibrous structure of the natural extracellular matrix. To evaluate its performances for possible implantation, the flow fields downstream the valve were accurately investigated and compared. The experimental results showed a correct functionality of the device, supported by the formation of vortex structures at the edge of the three cusps, with Reynolds stress values below the threshold for the risk of hemolysis (which can be comprised in the range 400-4000N/m(2) depending on the exposure period), and a good structural resistance to the mechanical loads generated by the driving pressure difference. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Heart valve tissue engineering: an overview of heart valve decellularization processes.

    Science.gov (United States)

    Boroumand, Safieh; Asadpour, Shiva; Akbarzadeh, Aram; Faridi-Majidi, Reza; Ghanbari, Hossein

    2018-01-01

    Despite recent advances in medicine and surgery, many people still suffer from cardiovascular diseases, which affect their life span and morbidity. Regenerative medicine and tissue engineering are novel approaches based on restoring or replacing injured tissues and organs with scaffolds, cells and growth factors. Scaffolds are acquired from two major sources, synthetic materials and naturally derived scaffolds. Biological scaffolds derived from native tissues and cell-derived matrix offer many advantages. They are more biocompatible with a higher affinity to cells, which facilitate tissue reconstruction. Interestingly, xenogeneic recipients generally tolerate their components. Therefore, heart valve tissue engineering is increasingly benefiting from naturally derived scaffolds. In this review, we investigated the different protocols and methods that have been used for heart valve decellularization.

  5. 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....

  6. Heart valve viscoelastic properties - a pilot study

    Directory of Open Access Journals (Sweden)

    Kochová P.

    2007-10-01

    Full Text Available The effects of cryopreservation on the biological tissue mechanics are still largely unknown. Generalized Maxwell model was applied to characterize quantitatively the viscoelastic behavior of sheep mitral heart valve tissue. Three different groups of specimens are supposed to be tested: fresh tissue specimens (control group, cryopreserved allografts from tissue bank and allografts already used as tissue replacements taken from the animals approximately one year after the surgery. Specific aim of this study is to determine whether or not the treatment used for storage in tissue bank influences significantly the mechanical properties and behavior of the tissue. At the moment, only the first group of specimens was examined. The methodology presented in this paper proved suitable to complete the study.

  7. T Cell Response in Patients with Implanted Biological and Mechanical Prosthetic Heart Valves.

    Science.gov (United States)

    Barbarash, L; Kudryavtsev, I; Rutkovskaya, N; Golovkin, A

    2016-01-01

    The study was aimed at assessing T cell subsets of peripheral blood from recipients of long-term functioning (more than 60 months) biological and mechanical heart valve prostheses. The absolute and relative number of CD4 and CD8 T cell subsets was analyzed: naïve (N, CD45RA(+)CD62L(+)), central memory (CM, CD45RA(-)CD62L(+)), effector memory (EM, CD45RA(-)CD62L(-)), and terminally differentiated CD45RA-positive effector memory (TEMRA, CD45RA(+)CD62L(-)) in 25 persons with biological and 7 with mechanical prosthesis compared with 48 apparently healthy volunteers. The relative and absolute number of central memory and naïve CD3(+)CD8(+) in patients with biological prosthesis was decreased (p mechanical prosthesis had increased absolute and relative number of CD45RA(+)CD62L(-)CD3(+)CD8(+) cells (p = 0.006). Also the relative number of CD3(+)CD4(+) cells was reduced (p = 0.04). We assume that altered composition of T cell subsets points at development of xenograft rejection reaction against both mechanical and biological heart valve prostheses.

  8. T Cell Response in Patients with Implanted Biological and Mechanical Prosthetic Heart Valves

    Directory of Open Access Journals (Sweden)

    L. Barbarash

    2016-01-01

    Full Text Available The study was aimed at assessing T cell subsets of peripheral blood from recipients of long-term functioning (more than 60 months biological and mechanical heart valve prostheses. The absolute and relative number of CD4 and CD8 T cell subsets was analyzed: naïve (N, CD45RA+CD62L+, central memory (CM, CD45RA−CD62L+, effector memory (EM, CD45RA−CD62L−, and terminally differentiated CD45RA-positive effector memory (TEMRA, CD45RA+CD62L− in 25 persons with biological and 7 with mechanical prosthesis compared with 48 apparently healthy volunteers. The relative and absolute number of central memory and naïve CD3+CD8+ in patients with biological prosthesis was decreased (p<0.001. Meanwhile the number of CD45RA+CD62L−CD3+CD8+ and CD3+CD4+ was increased (p<0.001. Patients with mechanical prosthesis had increased absolute and relative number of CD45RA+CD62L−CD3+CD8+ cells (p=0.006. Also the relative number of CD3+CD4+ cells was reduced (p=0.04. We assume that altered composition of T cell subsets points at development of xenograft rejection reaction against both mechanical and biological heart valve prostheses.

  9. Two monitoring methods of oral anticoagulant therapy in patients with mechanical heart valve prothesis: a meta-analysis.

    Science.gov (United States)

    Xu, Zhe; Wang, Zhiping; Ou, Jingsong; Xu, Yingqi; Yang, Song; Zhang, Xi

    2012-01-01

    Oral anticoagulant therapy (OAT) with warfarin has become the standard therapy for the patients with mechanical heart valve prothesis. The monitoring method of self-monitoring or self-management was promising to optimize the use of warfarin, but most of previous studies have included patients with various indications of OAT, which made it difficult to extrapolate the results to the specific patient population with mechanical heart valve prostheses. This study was intended to evaluate the new and traditional monitoring methods in patients with mechanical heart valve prostheses. Relevant literature finished before Dec. 2010 were searched through a number of digital databases. And then they were pooled by RevMan 4.2 and R 2.13.0 in three fields: rate within the target range, test frequency and occurrence rate of poor events. Five randomized control trials with a total of 2,219 patients were identified. Pooled estimates showed reductions in thromboembolic events (OR 0.52, 95% CI 0.35-0.77; P = 0.0012) and all-cause mortality (OR 0.50, 95% CI 0.29-0.86; P = 0.0115). No difference was noted in major and minor haemorrhage. All trials reported improvements in the mean proportion of international normalized ratios in range. Self-monitoring and self-management can improve the quality of OAT in the patients with mechanical heart valve prostheses. The patients spend more time within the therapeutic range resulting in decreases in thromboembolic events and mortality, with no increase in haemorrhage. However, self-monitoring and self-management was not feasible for all patients, and require identification and education of suitable candidates. The success of self-monitoring and self-management method depends on consistent, regular, and frequent testing.

  10. Long-term tricuspid valve prosthesis-related complications in patients with congenital heart disease.

    Science.gov (United States)

    van Slooten, Ymkje J; Freling, Hendrik G; van Melle, Joost P; Mulder, Barbara J M; Jongbloed, Monique R M; Ebels, Tjark; Voors, Adriaan A; Pieper, Petronella G

    2014-01-01

    In patients with acquired valvar disease, morbidity and mortality rates after tricuspid valve replacement (TVR) are high. However, in adult patients with congenital heart disease, though data concerning outcome after TVR are scarce, even poorer results are suggested in patients with Ebstein anomaly. To investigate the applicability of these results to a broader array of congenital heart disease patients, we report the long-term follow-up of prosthesis-related complications, including re-replacement of patients with a tricuspid valve prosthesis and congenital heart disease. From the Dutch Congenital Corvitia (CONCOR) registry, we identified 20 patients with a biological or mechanical tricuspid valve prosthesis implanted between 1977 and 2012 (total of 31 prostheses). We analysed the tricuspid valve-related complications and mortality. Ten patients with a median age of 16.2 years at the time of surgery (interquartile range 13.2-28.2 years) received a bioprosthesis while 10 patients with a median age of 36.4 years (interquartile range 14.0-47.0) at the time of surgery received a mechanical prosthesis (P = 0.28). During a mean follow-up of 14 years, 50% needed a re-replacement because of valve-related complications (e.g. valve degeneration or valve thrombosis). The yearly percentage of patients with valve-related complications was 4.2% in patients with a bioprosthesis and 2.7% in those with a mechanical prosthesis. Within 20 years of implantation, the median duration of event-free survival was significantly shorter in 3 patients with a prosthesis-patient mismatch (PPM; 1.0 year; interquartile range 0.01-2.6), compared with 7 without mismatch (8.0 years; interquartile range 5.1-12.3; P = 0.02). Compared with previous literature on acquired valvar disease, we found a higher incidence of valve-related complications in patients with congenital heart disease that was unrelated to prosthesis material. Our data suggest that PPM may have a negative effect on the event

  11. Computational Hemodynamic Investigation of Bileaflet and Trileaflet Mechanical Heart Valves.

    Science.gov (United States)

    Kuan, Yee Han; Nguyen, Vinh-Tan; Kabinejadian, Foad; Leo, Hwa Liang

    2015-05-01

    The trileaflet heart valve is a more desirable mechanical heart valve due to its similarity to native heart valves, which produce a central blood flow with decreased blood flow disturbance. There are, however, many challenges and difficulties in designing a trileaflet valve, mainly due to a greater number of moving mechanical parts. The flow profiles through a bileaflet mechanical heart valve (BMHV) and a trileaflet mechanical heart valve (TMHV) were compared at downstream regions. Geometric models of a 29 mm St. Jude Medical BMHV and a TMHV were used and positioned at the anatomic position in a curved aortic downstream geometry. Three-dimensional numerical simulations for both types of mechanical heart valve were performed under normal physiological pulsatile flow conditions. Flow profiles were studied under three different implantation locations at Z = 1D (D = 29 mm inlet diameter), 2D and 4D along the aorta centerline during peak systole. The simulation results showed different flow fields at the downstream positions at Z = 1D and 2D. The leaflets of the BMHV obstructed the flow, while the TMHV allowed a central orifice flow which resulted in a more physiological flow profile. Further downstream, at Z = 4D, the flow fields shared similarities in terms of the flow profile and velocity magnitude. The findings of this study may help to further improve the development of the TMHV.

  12. 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.

  13. Bridge Therapy Outcomes in Patients With Mechanical Heart Valves.

    Science.gov (United States)

    Delate, Thomas; Meisinger, Stephanie M; Witt, Daniel M; Jenkins, Daniel; Douketis, James D; Clark, Nathan P

    2017-11-01

    Bridge therapy is associated with an increased risk of major bleeding in patients with atrial fibrillation and venous thromboembolism (TE) without a corresponding reduction in TE. The benefits of bridge therapy in patients with mechanical heart valve (MHV) prostheses interrupting warfarin for invasive procedures are not well described. A retrospective cohort study was conducted at an integrated health-care delivery system. Anticoagulated patients with MHV interrupting warfarin for invasive diagnostic or surgical procedures between January 1, 2006, and March 31, 2012, were identified. Patients were categorized according to exposure to bridge therapy during the periprocedural period and TE risk (low, medium, and high). Outcomes validated via manual chart review included clinically relevant bleeding, TE, and all-cause mortality in the 30 days following the procedure. There were 547 procedures in 355 patients meeting inclusion criteria. Mean cohort age was 65.2 years, and 38% were female. Bridge therapy was utilized in 466 (85.2%) procedures (95.2%, 77.3%, and 65.8% of high, medium, and low TE risk category procedures, respectively). The 30-day rate of clinically relevant bleeding was numerically higher in bridged (5.8%; 95% confidence interval [CI], 3.9%-8.3%) versus not bridged procedures (1.2%; 95% CI, <0.1%-6.7%; P = .102). No TEs or deaths were identified. The use of bridge therapy is common among patients with MHV and may be associated with increased bleeding risk. Further research is needed to determine whether bridge therapy reduces TE in patients with MHV interrupting warfarin for invasive procedures.

  14. 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 costs of healthcare use and sick leave among heart valve surgery patients over 12 months post surgery. METHODS: We conducted a nationwide survey on the CR participation of all patients having undergone valve surgery between 1 January 2011 and 30 June 2011 (n=667). Among the responders (n=500, 75...... expensive outpatient visits. Further studies should investigate the benefits of CR to heart valve surgery patients as part of a formal cost-utility analysis....

  15. pattern of anticoagulation control after heart valve surgery

    African Journals Online (AJOL)

    hi-tech

    2000-07-07

    Jul 7, 2000 ... Objective: To determine the pattern of anticoagulation control for post heart-valve surgery for patients on ... quality control systems are in place, levels of adequate ..... in Haematoloty, Haemostasis and Thrombosis Task Force.

  16. Comparison of the occurrence of thromboembolic and bleeding complications in patients with mechanical heart valve prosthesis with one and two leaflets in the mitral position

    Science.gov (United States)

    de Campos, Nelson Leonardo Kerdahi Leite

    2014-01-01

    Introduction Patients with mechanical heart valve prostheses must continuously be treated with oral anticoagulants to prevent thromboembolic events related to prosthetesis. These patients should be continually evaluated for the control of oral anticoagulation. Objective To compare the occurrence of thromboembolic and hemorragic complications in patients with mechanical heart valve prosthesis with one (mono) and two (bi) leaflets in the mitral position in anticoagulant therapy. Methods We studied the 10-year interval, 117 patients with prosthesis in the mitral position, 48 with prosthetic single leaflet and 69 with two leaflets. We evaluated the occurrence of thromboembolic and hemorrhagic major and minor degree under gravity. The results are presented in an actuarial study and the frequency of occurrence of linear events. Results The actuarial survival curves showed that over time, patients with prosthetic heart valve with one leaflet were less free of thromboembolic complications than patients with two leaflet prosthetic valve, while the latter (two leaflet) were less free of hemorrhagic accidents. The linearized frequency of occurrence of thromboembolism were higher in patients with mono leaflet prosthesis. Bleeding rates were higher for patients with bi leaflet prosthetic valve. Conclusion Patients with mono leaflet prosthetic heart valve showed that they are more prone to the occurrence of serious thromboembolic events compared to those with bi leaflet prosthetic valve. Patients with bi leaflet prosthetic valve had more bleeding than patients with mono leaflet prosthetic valve, however this difference was restricted to the bleeding of minor nature. PMID:24896164

  17. The Application of Bileaflet Mechanical Heart Valves in the Polish Ventricular Assist Device: Physical and Numerical Study and First Clinical Usage.

    Science.gov (United States)

    Malota, Zbigniew; Sadowski, Wojciech; Krzyskow, Marek; Stolarzewicz, Bogdan

    2016-03-01

    The Polish ventricular assist device (Polvad) has been used successfully in clinical contexts for many years. The device contains two single-disc valves, one at the inlet and one at the outlet connector of the pneumatic pump. Unfortunately, in recent years, a problem has occurred with the availability of single-disc valves. This article presents the possibility of using bileaflet mechanical heart valve prostheses in the Polvad to avoid a discontinuity in clinical use. The study is based on experimental and numerical simulations and comparison of the distribution of flow, pressure, and stress (wall, shear, and turbulent) inside the Polvad chamber and the inlet/outlet connectors fitted with Sorin Monodisc and Sorin Bicarbon Fitline valves. The type and orientation of the inlet valve affects valve performance and flow distribution inside the chamber. Near-wall flow is observed for single-disc valves. In the case of bileaflet valves, the main jet is directed more centrally, with lower shear stress but higher turbulent stress in comparison with single-disc valves. For clinical usage, a 45° orientation of the bileaflet inlet valve was chosen, as this achieves good washing of the inlet area near the membrane paste surface. The Polvad with bileaflet valves has now been used successfully in our clinic for over a year and will continue to be used until new assist devices for heart support are developed. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

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

    Science.gov (United States)

    Hulin, Alexia; Moore, Vicky; James, Jeanne M; Yutzey, Katherine E

    2017-01-01

    Myxomatous valve disease (MVD) is the most common aetiology of primary mitral regurgitation. Recent studies suggest that defects in heart valve development can lead to heart valve disease in adults. Wnt/β-catenin signalling is active during heart valve development and has been reported in human MVD. The consequences of increased Wnt/β-catenin signalling due to Axin2 deficiency in postnatal valve remodelling and pathogenesis of MVD were determined. To investigate the role of Wnt/β-catenin signalling, we analysed heart valves from mice deficient in Axin2 (KO), a negative regulator of Wnt/β-catenin signalling. Axin2 KO mice display enlarged mitral and aortic valves (AoV) after birth with increased Wnt/β-catenin signalling and cell proliferation, whereas Sox9 expression and collagen deposition are decreased. At 2 months in Axin2 KO mice, the valve extracellular matrix (ECM) is stratified but distal AoV leaflets remain thickened and develop aortic insufficiency. Progressive myxomatous degeneration is apparent at 4 months with extensive ECM remodelling and focal aggrecan-rich areas, along with increased BMP signalling. Infiltration of inflammatory cells is also observed in Axin2 KO AoV prior to ECM remodelling. Overall, these features are consistent with the progression of human MVD. Finally, Axin2 expression is decreased and Wnt/β-catenin signalling is increased in myxomatous mitral valves in a murine model of Marfan syndrome, supporting the importance of Wnt/β-catenin signalling in the development of MVD. Altogether, these data indicate that Axin2 limits Wnt/β-catenin signalling after birth and allows proper heart valve maturation. Moreover, dysregulation of Wnt/β-catenin signalling resulting from loss of Axin2 leads to progressive MVD. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For Permissions, please email: journals.permissions@oup.com.

  19. Cardiac crossroads: deciding between mechanical or bioprosthetic heart valve replacement

    Science.gov (United States)

    Tillquist, Maggie N; Maddox, Thomas M

    2011-01-01

    Nearly 15 million people in the United States suffer from either aortic or mitral valvular disease. For patients with severe and symptomatic valvular heart disease, valve replacement surgery improves morbidity and mortality outcomes. In 2009, 90,000 valve replacement surgeries were performed in the United States. This review evaluates the advantages and disadvantages of mechanical and bioprosthetic prosthetic heart valves as well as the factors for consideration in deciding the appropriate valve type for an individual patient. Although many caveats exist, the general recommendation is for patients younger than 60 to 65 years to receive mechanical valves due to the valve’s longer durability and for patients older than 60 to 65 years to receive a bioprosthetic valve to avoid complications with anticoagulants. Situations that warrant special consideration include patient co-morbidities, the need for anticoagulation, and the potential for pregnancy. Once these characteristics have been considered, patients’ values, anxieties, and expectations for their lifestyle and quality of life should be incorporated into final valve selection. Decision aids can be useful in integrating preferences in the valve decision. Finally, future directions in valve technology, anticoagulation, and medical decision-making are discussed. PMID:21448466

  20. Volumetric velocity measurements on flows through heart valves

    Science.gov (United States)

    Troolin, Daniel; Amatya, Devesh; Longmire, Ellen

    2009-11-01

    Volumetric velocity fields inside two types of artificial heart valves were obtained experimentally through the use of volumetric 3-component velocimetry (V3V). Index matching was used to mitigate the effects of optical distortions due to interfaces between the fluid and curved walls. The steady flow downstream of a mechanical valve was measured and the results matched well with previously obtained 2D PIV results, such as those of Shipkowitz et al. (2002). Measurements upstream and downstream of a deformable silicone valve in a pulsatile flow were obtained and reveal significant three-dimensional features of the flow. Plots and movies will be shown, and a detailed discussion of the flow and various experimental considerations will be included. Reference: Shipkowitz, T, Ambrus J, Kurk J, Wickramasinghe K (2002) Evaluation technique for bileaflet mechanical valves. J. Heart Valve Disease. 11(2) pp. 275-282.

  1. TRINITY heart valve prosthesis: a novel repositionable and retrievable transapical transcatheter aortic valve system.

    Science.gov (United States)

    Hengstenberg, Christian; Condado, Jose; Garcia, David; Martinez, Milka Marin; La Forgia, Giambattista; Ebner, Adrian; Gallo, Santiago; Silva, Enrique; Holzamer, Andreas; Husser, Oliver; Hilker, Michael

    2015-03-01

    Transcatheter aortic valve implantation (TAVI) has become a viable option for selected high-risk patients with severe and symptomatic aortic stenosis. First- and second-generation TAVI devices are either self- or balloon-expandable, and are often not repositionable or not fully retrievable, leading to suboptimal positioning in some cases. This may result in paravalvular regurgitation, AV conduction delay, or compromise of coronary perfusion. A broader application of TAVI requires advances in both valve and delivery systems. Therefore, in order to facilitate accurate positioning, to minimise paravalvular leakage, possibly to reduce the risk of AV conduction delay, and possibly to be able to abort the procedure, a "next-generation" TAVI system has been developed which is repositionable and retrievable, the TRINITY heart valve system. The TRINITY heart valve system was implanted in a first-in-human study using the transapical approach to demonstrate feasibility and procedural success. All endpoints were adjudicated according to VARC definitions at seven and 30 days. The TRINITY heart valve system was implanted in a 74-year-old patient with severe symptomatic aortic valve stenosis. In this case, repositioning of the TRINITY resulted in optimal position without paravalvular leakage and with perfect function. The TRINITY heart valve is a repositionable and retrievable TAVI system. Both the implantation result and short-term clinical and haemodynamic outcome were excellent.

  2. SURGICAL CORRECTION OF HEART VALVE DISEASE WITH CARDIOPULMONARY BYPASS IN PATIENTS AFTER RENAL TRANSPLANTATION

    Directory of Open Access Journals (Sweden)

    D. A. Belokurov

    2013-01-01

    Full Text Available Aim. Evaluation of the possibility heart valve replacement in renal transplant recipients from a position of safe- ty for graft function. Materials and methods. 5 patients, heart valve replacement was performed with a func- tioning kidney transplant at a satisfactory its function. The average age of patients at the time of cardiac surgery was 38,8 ± 12,6 years, among whom were two (40% men and 3 (60% women. The interval between renal transplantation and heart surgery was 40,3 ± 44,1 (2 to 120 months. Prior to kidney transplantation, all patients were on renal replacement therapy with hemodialysis program for 50,2 ± 48,6 months. In 4 of the 5 patients of heart disease was the cause of infective endocarditis. Results. Average time IR was 81,2 ± 21,7 minutes , the average time of aortic clamping 63,6 ± 20,9 minutes and hypothermia during CPB 29,2 ± 3,2 °C. All patients were implanted with double-leaf mechanical prostheses "MedEng-2" and "SarboMedics". All 5 patients in sa- tisfactory condition were discharged from the hospital. The average duration of the postoperative period was 14,2 ± 3,4 days. All patients had relatively smooth flow after surgery, no infectious complications, a satisfactory renal transplant function and prosthetic heart valves. In the late period in four patients and transplant graft func- tion is satisfactory in terms of the observation of 5 years, 3 years and 6 months after surgery. Conclusion. Our experience shows the possibility of successful correction of heart defects in IR in renal transplant recipients. 

  3. Physical activity increases survival after heart valve surgery

    DEFF Research Database (Denmark)

    Lund, K.; Sibilitz, Kirstine Lærum; Kikkenborg Berg, Selina

    2016-01-01

    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...... of physical activity after heart valve surgery are positively associated with higher survival rates and participation in cardiac rehabilitation.......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...

  4. Profile of Heart Donors from the Human Valve Bank of the Santa Casa de Misericórdia de Curitiba.

    Science.gov (United States)

    Ferreira, Renata Maria; da Costa, Marise Teresinha Brenner Affonso; Canciglieri Junior, Osiris; Sant'Anna, Ângelo Márcio Oliveira

    2016-04-01

    Human heart valves are used as replacement valves and have satisfactory functional results compared with conventional prostheses. Characterize the profile of effective heart donors from the human valve bank of the santa casa de misericórdia de curitiba and analyze the association between the profile variables. It consists of a retrospective and quantitative study of electronic medical records from heart donors for heart valves. every heart donation made to the bank between january 2004 and december 2014 was studied. 2,149 donations were analyzed, from donors aged 0 to 71 years old, with an average of 34.9 ± 15.03 years old. most donors were male 65.7% (n=1,411) and 34.3% (n=738) were female. among the most frequent causes of the donors' death are trauma at 53% (n=1,139) and cerebral vascular accident at 34.2% (n=735). there was significant statistical association between the analyzed variables. There has been an improvement in brazil's donation rate, being essential that the tissue banks work together with the state and federal district centers for notification, procurement and distribution of organs in order to increase the number of donors.

  5. Profile of Heart Donors from the Human Valve Bank of the Santa Casa de Misericórdia de Curitiba

    Science.gov (United States)

    Ferreira, Renata Maria; da Costa, Marise Teresinha Brenner Affonso; Canciglieri Junior, Osiris; Sant'Anna, Ângelo Márcio Oliveira

    2016-01-01

    Introduction Human heart valves are used as replacement valves and have satisfactory functional results compared with conventional prostheses. Objective Characterize the profile of effective heart donors from the human valve bank of the santa casa de misericórdia de curitiba and analyze the association between the profile variables. Methods It consists of a retrospective and quantitative study of electronic medical records from heart donors for heart valves. every heart donation made to the bank between january 2004 and december 2014 was studied. Results 2,149 donations were analyzed, from donors aged 0 to 71 years old, with an average of 34.9 ± 15.03 years old. most donors were male 65.7% (n=1,411) and 34.3% (n=738) were female. among the most frequent causes of the donors' death are trauma at 53% (n=1,139) and cerebral vascular accident at 34.2% (n=735). there was significant statistical association between the analyzed variables. Conclusion There has been an improvement in brazil's donation rate, being essential that the tissue banks work together with the state and federal district centers for notification, procurement and distribution of organs in order to increase the number of donors. PMID:27556322

  6. 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.

  7. A Study on the Mechanism for Cavitation in the Mechanical Heart Valves with an Electrohydraulic Total Artificial Heart

    Science.gov (United States)

    Lee, Hwansung; Tsukiya, Tomonori; Homma, Akihiko; Kamimura, Tadayuki; Tatsumi, Eisuke; Taenaka, Yoshiyuki; Kitamura, Soichiro

    It has been conceived that the mechanical heart valves mounted in an artificial heart close much faster than in vivo use, resulting in cavitation bubbles formation. In this study, the mechanisms for cavitation in mechanical heart valves (MHVs) is investigated with monoleaflet and bileaflet valves in the mitral position with an electrohydraulic total artificial heart (EHTAH). The valve-closing velocity and pressure-drop through the valve were done, and a high-speed video camera was employed to investigate the mechanism for MHVs cavitation. The valve-closing velocity and pressure-drop of the bileaflet valves were less than that of the monoleaflet valves. Most of the cavitation bubbles in the monoleaflet valves were observed next to the edge of the valve stop and the inner side of the leaflet. With the bileaflet valves, cavitation bubbles were concentrated along the leaflet tip. Also, the number density of cavitation bubbles in the bileaflet valves was less than that of the monoleaflet valves. The number density of cavitation bubbles increased with an increase in the valve-closing velocity and the valve stop area. It is established that squeeze flow holds the key to cavitation in the mechanical heart valve. In a viewpoint of squeeze flow, the bileaflet valve with slow valve-closing velocity and small valve stop area, is safer to prevent of blood cell damage than the monoleaflet valves.

  8. Mechanisms of mechanical heart valve cavitation in an electrohydraulic total artificial heart.

    Science.gov (United States)

    Lee, Hwansung; Taenaka, Yoshiyuki; Kitamura, Soichiro

    2005-01-01

    Until now, we have estimated cavitation for mechanical heart valves (MHV) mounted in an electrohydraulic total artificial heart (EHTAH) with tap water as a working fluid. However, tap water at room temperature is not a proper substitute for blood at 37 degrees C. We therefore investigated MHV cavitation using a glycerin solution that was identical in viscosity and vapor pressure to blood at body temperature. In this study, six different kinds of monoleaflet and bileaflet valves were mounted in the mitral position in an EHTAH, and we investigated the mechanisms for MHV cavitation. The valve closing velocity, pressure drop measurements, and a high-speed video camera were used to investigate the mechanism for MHV cavitation and to select the best MHV for our EHTAH. The closing velocity of the bileaflet valves was slower than that of the monoleaflet valves. Cavitation bubbles were concentrated on the edge of the valve stop and along the leaflet tip. It was established that squeeze flow holds the key to MHV cavitation in our study. Cavitation intensity increased with an increase in the valve closing velocity and the valve stop area. With regard to squeeze flow, the Björk-Shiley valve, because it is associated with slow squeeze flow, and the bileaflet valve with low valve closing velocity and small valve stop areas are better able to prevent blood cell damage than the monoleaflet valves.

  9. Valvular Heart Disease in Adults: Management of Prosthetic Heart Valves.

    Science.gov (United States)

    Trujillo, John F; Hollenberg, Steven M

    2017-06-01

    Patients undergoing cardiac valve replacement may receive mechanical or bioprosthetic valves. Mechanical valves require lifelong anticoagulation but are durable and the need for a second surgery is up to eightfold times less than with bioprosthetic valves. Bioprosthetic valves do not require lifelong anticoagulation and thus are associated with fewer bleeding complications but they are less durable and associated with higher morbidity and mortality rates, particularly in younger patients. Anticoagulation with mechanical valves is achieved using warfarin; use of direct-acting oral anticoagulants is not indicated. Concomitant low-dose aspirin is recommended for patients with mechanical valves and as sole thromboembolism prophylaxis for patients receiving aortic or mitral bioprosthetic valves. If a patient taking warfarin is to undergo a surgical procedure that requires interruption of anticoagulation, bridging therapy with heparin is indicated if the patient has a mechanical aortic valve and any risk of thromboembolism, an older-generation mechanical aortic valve, or a mechanical mitral valve. Warfarin is teratogenic; pregnant women should take heparin. Patients with mechanical or bioprosthetic valves should receive antibiotic prophylaxis before some dental and surgical procedures to prevent endocarditis. Thrombolytic therapy should be considered in patients who develop a thrombus on a valve that does not resolve with heparin. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  10. Space-time fluid mechanics computation of heart valve models

    Science.gov (United States)

    Takizawa, Kenji; Tezduyar, Tayfun E.; Buscher, Austin; Asada, Shohei

    2014-10-01

    Fluid mechanics computation of heart valves with an interface-tracking (moving-mesh) method was one of the classes of computations targeted in introducing the space-time (ST) interface tracking method with topology change (ST-TC). The ST-TC method is a new version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method. It can deal with an actual contact between solid surfaces in flow problems with moving interfaces, while still possessing the desirable features of interface-tracking methods, such as better resolution of the boundary layers. The DSD/SST method with effective mesh update can already handle moving-interface problems when the solid surfaces are in near contact or create near TC, if the "nearness" is sufficiently "near" for the purpose of solving the problem. That, however, is not the case in fluid mechanics of heart valves, as the solid surfaces need to be brought into an actual contact when the flow has to be completely blocked. Here we extend the ST-TC method to 3D fluid mechanics computation of heart valve models. We present computations for two models: an aortic valve with coronary arteries and a mechanical aortic valve. These computations demonstrate that the ST-TC method can bring interface-tracking accuracy to fluid mechanics of heart valves, and can do that with computational practicality.

  11. Aortic valve prosthesis-patient mismatch and exercise capacity in adult patients with congenital heart disease.

    Science.gov (United States)

    van Slooten, Ymkje J; van Melle, Joost P; Freling, Hendrik G; Bouma, Berto J; van Dijk, Arie Pj; Jongbloed, Monique Rm; Post, Martijn C; Sieswerda, Gertjan T; Huis In 't Veld, Anna; Ebels, Tjark; Voors, Adriaan A; Pieper, Petronella G

    2016-01-01

    To report the prevalence of aortic valve prosthesis-patient mismatch (PPM) in an adult population with congenital heart disease (CHD) and its impact on exercise capacity. Adults with congenital heart disease (ACHD) with a history of aortic valve replacement may outgrow their prosthesis later in life. However, the prevalence and clinical consequences of aortic PPM in ACHD are presently unknown. From the national Dutch Congenital Corvitia (CONCOR) registry, we identified 207 ACHD with an aortic valve prosthesis for this cross-sectional cohort study. Severe PPM was defined as an indexed effective orifice area ≤0.65 cm2/m2 and moderate PPM as an indexed orifice area ≤0.85 cm2/m2 measured using echocardiography. Exercise capacity was reported as percentage of predicted exercise capacity (PPEC). Of the 207 patients, 68% was male, 71% had a mechanical prosthesis and mean age at inclusion was 43.9 years ±11.4. The prevalence of PPM was 42%, comprising 23% severe PPM and 19% moderate PPM. Prevalence of PPM was higher in patients with mechanical prostheses (pHeart Association (NYHA) class remained stable in most patients. PPM showed no significant effect on death or hospitalisation during follow-up (p=0.218). In this study we report a high prevalence (42%) of PPM in ACHD with an aortic valve prosthesis and an independent association of PPM with diminished exercise capacity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  12. Adherence of staphylococcus aureus to dyneema Purity® patches and to clinically used cardiovascular prostheses

    NARCIS (Netherlands)

    Basir, Amir; Gründeman, Paul; Moll, Frans; Herwaarden, van Joost; Pasterkamp, Gerard; Nijland, Reindert

    2016-01-01

    Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for

  13. Experimental Investigation of Flow trough a Mechanical Heart Valve

    Science.gov (United States)

    Haji-Esmaeili, Farida; Oshkai, Peter

    2006-11-01

    Turbulent flow trough a model of a mechanical heart valve is investigated using digital particle image velocimetry. The valve leaflets are represented by flat plates mounted in a duct. The emphasis is on the effect of the valve design on the platelet activation state associated with the resulting flow field. Global quantitative images corresponding to multiple planes of data acquisition provide insight into the three-dimensional nature of the flow. Turbulent flow structures including jet-like regions and shed vortices are characterized in terms of patterns of instantaneous and time-averaged velocity, vorticity, and streamline topology. Potential of bileaflet heart valves for being thrombogenic is assessed by quantitative comparison of the associated flow fields in terms of maximum values of turbulent stresses and platelet activation states.

  14. 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.

  15. Porphyromonas gingivalis in periodontal pockets and heart valves.

    Science.gov (United States)

    Radwan-Oczko, Małgorzata; Jaworski, Aleksander; Duś, Irena; Plonek, Tomasz; Szulc, Malgorzata; Kustrzycki, Wojciech

    2014-05-15

    There is evidence that advanced infectious chronic periodontal inflammatory disease may have an impact on general health including cardiovascular diseases. The aim of this clinical study was to evaluate the ability of Porphyromonas gingivalis to colonize heart valves and, subsequently, to assess whether there is an association between the presence of the DNA of Porphyromonas gingivalis in periodontal pockets and in degenerated heart valves. Thirty patients were enrolled in the study and 31 valve specimens harvested during cardiac surgery operations were examined. All patients underwent a periodontal examination. To evaluate the periodontal status of the patients the following clinical parameters were recorded: the pocket depth, bleeding on probing (BOP) and aproximal plaque index (API). The presence of P. gingivalis in heart valve specimens and samples from periodontal pockets was analyzed using a single-step PCR method. P. gingivalis DNA was detected in periodontal pockets of 15 patients (50%). However, the DNA of this periopathogen was found neither in the aortic nor in the mitral valve specimens. This study suggests that P. gingivalis may not have an influence on the development of the degeneration of aortic and mitral valves.

  16. Adherence of Staphylococcus aureus to Dyneema Purity® Patches and to Clinically Used Cardiovascular Prostheses

    OpenAIRE

    Basir, Amir; Grundeman, Paul; Moll, Frans; van Herwaarden, Joost; Pasterkamp, Gerard; Nijland, Reindert

    2016-01-01

    Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for prostheses is Dyneema Purity®, made of ultra-high-molecularweight polyethylene. Dyneema Purity® fibers are very thin, flexible, resistant to fatigue and abrasion, and have high strength. S. aureus ad...

  17. Effects of Leaflet Design on Transvalvular Gradients of Bioprosthetic Heart Valves.

    Science.gov (United States)

    Dabiri, Yaghoub; Ronsky, Janet; Ali, Imtiaz; Basha, Ameen; Bhanji, Alisha; Narine, Kishan

    2016-12-01

    Bioprosthetic aortic valves (BAVs) are becoming the prostheses of choice in heart valve replacement. The objective of this paper is to assess the effects of leaflet geometry on the mechanics and hemodynamics of BAVs in a fluid structure interaction model. The curvature and angle of leaflets were varied in 10 case studies whereby the following design parameters were altered: a circular arch, a line, and a parabola for the radial curvature, and a circular arch, a spline, and a parabola for the circumferential curvature. Six different leaflet angles (representative of the inclination of the leaflets toward the surrounding aortic wall) were analyzed. The 3-dimensional geometry of the models were created using SolidWorks, Pointwise was used for meshing, and Comsol Multiphysics was used for implicit finite element calculations. Realistic loading was enforced by considering the time-dependent strongly-coupled interaction between blood flow and leaflets. Higher mean pressure gradients as well as von Mises stresses were obtained with a parabolic or circular curvature for radial curvature or a parabolic or spline curvature for the circumferential curvature. A smaller leaflet angle was associated with a lower pressure gradient, and, a lower von Mises stress. The leaflet curvature and angle noticeably affected the speed of valve opening, and closing. When a parabola was used for circumferential or radial curvature, leaflets displacements were asymmetric, and they opened and closed more slowly. A circular circumferential leaflet curvature, a linear leaflet radial curvature, and leaflet inclination toward the surrounding aortic wall were associated with superior BAVs mechanics.

  18. Superhydrophobicity to minimize thrombogenic risk on mechanical heart valves

    Science.gov (United States)

    Bark, David; Vahabi, Hamed; Movafaghi, Sanli; Popat, Ketul; Kota, Arun K.; Dasi, Lakshmi Prasad

    2017-11-01

    A large number of prosthetic heart valves are implanted each year to treat heart valve disease, where half of the surgically replaced valves are mechanical heart valves (MHV)s. MHVs are at high risk for thrombosis and therefore require lifelong antithrombotic therapies, causing an increased bleeding risk that can lead to death. To alleviate this need, we investigate the potential of superhydrophobic surfaces in reducing the thrombotic risk. Particle imaging velocimetry and computational fluid dynamics are used to quantify shear stress in the presence of potential slip on the surface. Coagulation and cell adhesion are quantified by incubating blood under static conditions. We further evaluate a dynamic blood response in polydimethylsiloxane channels under complex shear conditions that mimic the hinge region of bileaflet mechanical heart valves, a region known to exhibit thrombosis. Overall, Shear stress is not reduced on a superhydrophobic bileaflet MHV. However, superhydrophobic surfaces significantly reduce the potential for platelet responses under static and dynamic blood flow conditions, a counterintuitive result when considering that hydrophobic surfaces are prone to protein and cell adhesion. The authors gratefully acknowledge funding from National Institutes of Health (NIH) under Award Number R01HL119824 and F32HL129730. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

  19. An up-to-date overview of the most recent transcatheter implantable aortic valve prostheses

    NARCIS (Netherlands)

    Wiegerinck, Esther M. A.; van Kesteren, Floortje; van Mourik, Martijn S.; Vis, Marije M.; Baan, Jan

    2016-01-01

    Over the past decade transcatheter aortic valve implantation (TAVI) has evolved towards the routine therapy for high-risk patients with severe aortic valve stenosis. Technical refinements in TAVI are rapidly evolving with a simultaneous expansion of the number of available devices. This review will

  20. Mechanical testing of pericardium for manufacturing prosthetic heart valves.

    Science.gov (United States)

    Aguiari, Paola; Fiorese, Michele; Iop, Laura; Gerosa, Gino; Bagno, Andrea

    2016-01-01

    Mammalian pericardia are currently used for the production of percutaneous prosthetic heart valves. The characteristics of biological tissues largely influence the durability of prosthetic devices used in the percutaneous approach and in traditional surgery, too. This paper reviews methodologies employed to assess and compare mechanical properties of pericardial patches from different mammalian species in order to identify the biomaterials adequate for manufacturing prosthetic heart valves. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  1. A new self-administered questionnaire to determine patient experience with voice prostheses (Blom-singer valves

    Directory of Open Access Journals (Sweden)

    Kazi R

    2005-01-01

    Full Text Available Aim: To obtain information about valved speech and related issues in patients who have undergone total laryngectomy with the help of a new structured questionnaire on voice prosthesis. Settings and Design: A questionnaire-based pilot study set at a tertiary referral head and neck cancer unit. Materials and Methods: Twenty-five patients using voice prostheses, who showed no signs of recurrence after having undergone total laryngectomy were interviewed with the help of a questionnaire that assessed issues such as voice quality, valve maintenance, leakage, quality of life, humidification and hands-free system over the preceding seven days. The data was analyzed using non-parametric tests (Mann-Whitney and Spearman rank. Results: Twenty-five patients (16 males with a median age of 65 years (IQ range: 59-70 years had been using the prosthesis for a median of 6 years (IQ range: 5-10 years. The majority of the patients (n=20 were fully informed about their valve size and diameter and most were able to remove and replace their own prosthesis. Fourteen patients (60% had leakage-related issues. Women were less satisfied with their voice quality as compared to men. Overall, there appeared to be an improvement in quality of life with the use of the voice prosthesis. Conclusions: The subjects were fairly well informed about their valve and experienced a high level of satisfaction with their voice. This questionnaire serves as a valuable tool for monitoring voice rehabilitation in patients who have undergone laryngectomy.

  2. Automated control of the laser welding process of heart valve scaffolds

    OpenAIRE

    Weber Moritz; Hoheisel Anna L.; Glasmacher Birgit

    2016-01-01

    Using the electrospinning process the geometry of a heart valve is not replicable by just one manufacturing process. To produce heart valve scaffolds the heart valve leaflets and the vessel have to be produced in separated spinning processes. For the final product of a heart valve they have to be mated afterwards. In this work an already existing three-axes laser was enhanced to laser weld those scaffolds. The automation control software is based on the robot operating system (ROS). The mecha...

  3. Effects of tilting disk heart valve gap width on regurgitant flow through an artificial heart mitral valve.

    Science.gov (United States)

    Maymir, J C; Deutsch, S; Meyer, R S; Geselowitz, D B; Tarbell, J M

    1997-09-01

    While many investigators have measured the turbulent stresses associated with forward flow through tilting disk heart valves, only recently has attention been given to the regurgitant jets formed as fluid is squeezed through the gap between the occluder and housing of a closed valve. The objective of this investigation was to determine the effect of gap width on the turbulent stresses of the regurgitant jets through a Björk-Shiley monostrut tilting disk heart valve seated in the mitral position of a Penn State artificial heart. A 2 component laser-Doppler velocimetry system with a temporal resolution of 1 ms was used to measure the instantaneous velocities in the regurgitant jets in the major and minor orifices around the mitral valve. The gap width was controlled through temperature variation by taking advantage of the large difference between the thermal expansion coefficients of the Delrin occluder and the Stellite housing of Björk-Shiley monostrut valves. The turbulent shear stress and mean (ensemble averaged) velocity were incorporated into a model of red blood cell damage to assess the potential for hemolytic damage at each gap width investigated. The results revealed that the minor orifice tends to form stronger jets during regurgitant flow than the major orifice, indicating that the gap width is not uniform around the circumference of the valve. Based on the results of a red blood cell damage model, the hemolytic potential of the mitral valve decreases as the gap width increases. This investigation also established that the hemolytic potential of the regurgitant phase of valve operation is comparable to, if not greater than, the hemolytic potential of forward flow, consistent with experimental data on hemolysis.

  4. Valvular Heart Disease in Adults: Management of Native Valve Disease.

    Science.gov (United States)

    Zhang, Xin; Hollenberg, Steven M

    2017-06-01

    Patients with valvular heart disease (VHD) should be treated for diabetes, hypertension, and hyperlipidemia. They also should receive therapy for left ventricular dysfunction, undergo interval echocardiography, and participate in aerobic exercise. Valve replacement should be considered for patients with aortic stenosis (AS) and syncope, presyncope, heart failure, angina, or severe AS with left ventricular dysfunction. Valve replacement is performed with open or transcatheter procedures; the latter are preferred for patients with high surgical risk. Patients with chronic aortic regurgitation (AR) should undergo open surgical replacement if they are symptomatic or are asymptomatic but have severe regurgitation and left ventricular dysfunction. No transcatheter procedures currently are approved for AR. Patients with mitral stenosis (MS) should receive drugs for heart rate control and anticoagulation if they have atrial fibrillation. Invasive treatment involves valve replacement or percutaneous commissurotomy. Management of severe chronic mitral regurgitation consists of valve replacement or, for patients with high surgical risk, a percutaneous transcatheter procedure that clips the mitral leaflets together. When severe, tricuspid regurgitation can be managed with valve replacement. Pregnant patients with VHD require special management. Women with severe AS or MS should avoid becoming pregnant until VHD is managed definitively. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  5. Surface heparin treatment of the decellularized porcine heart valve : Effect on tissue calcification

    NARCIS (Netherlands)

    Yang, Min; Lin, Yang-Hua; Shi, Wei-Ping; Shi, Hong-Can; Gu, Y. John; Shu, Yu-Sheng

    Tissue calcification is a major cause of failure of bioprosthetic heart valves. Aim of this study was to examine whether surface heparin treatment of the decellularized porcine heart valve reduces tissue calcification. Fresh porcine aortic heart valves were dissected as tissue discs and divided into

  6. A novel approach in cross-linking of bioprosthetic heart valves

    NARCIS (Netherlands)

    Everaerts, Fransiscus Joannes Leonardus

    2007-01-01

    Due to some form of heart valve disease, approximately 250000 patients worldwide undergo surgery to receive a new heart-valve each year. In about 70% of the cases a mechanical heart valve is used despite the fact that permanent anticoagulant therapy for the patient is required. The remaining 30% of

  7. Balloon expandable transcatheter heart valves for native mitral valve disease with severe mitral annular calcification.

    Science.gov (United States)

    Guerrero, Mayra; Urena, Marina; Pursnani, Amit; Wang, Dee D; Vahanian, Alec; O'Neill, William; Feldman, Ted; Himbert, Dominique

    2016-06-01

    Patients with mitral annular calcification (MAC) have high surgical risk for mitral valve replacement due to associated comorbidities and technical challenges related to calcium burden, precluding surgery in many patients. Transcatheter mitral valve replacement (TMVR) with the compassionate use of balloon expandable aortic transcatheter heart valves has been used in this clinical scenario. The purpose of this review was to summarize the early experience including successes and failures reported. TMVR might evolve into an acceptable alternative for selected patients with severe MAC who are not candidates for conventional mitral valve surgery. However, this field is at a very early stage and the progress will be significantly slower than the development of transcatheter aortic valve replacement due to the complexity of the mitral valve anatomy and its pathology. Optimizing patient selection process by using multimodality imaging tools to accurately measure the mitral valve annulus and evaluate the risk of left ventricular outflow tract obstruction is essential to minimize complications. Strategies for treating and preventing left ventricular outflow tract obstruction are being tested. Similarly, carefully selecting candidates avoiding patients at the end of their disease process, might improve the overall outcomes.

  8. A new approach to heart valve tissue engineering

    DEFF Research Database (Denmark)

    Kaasi, Andreas; Cestari, Idágene A.; Stolf, Noedir A G.

    2011-01-01

    chamber. Subsequently, applied vacuum to the pneumatic chamber causes the blood chamber to fill. A mechanical heart valve was placed in the VAD's inflow position. The tissue engineered (TE) valve was placed in the outflow position. The VAD was coupled in series with a Windkessel compliance chamber......The 'biomimetic' approach to tissue engineering usually involves the use of a bioreactor mimicking physiological parameters whilst supplying nutrients to the developing tissue. Here we present a new heart valve bioreactor, having as its centrepiece a ventricular assist device (VAD), which exposes...... the cell-scaffold constructs to a wider array of mechanical forces. The pump of the VAD has two chambers: a blood and a pneumatic chamber, separated by an elastic membrane. Pulsatile air-pressure is generated by a piston-type actuator and delivered to the pneumatic chamber, ejecting the fluid in the blood...

  9. Heart sounds as a result of acoustic dipole radiation of heart valves

    Science.gov (United States)

    Kasoev, S. G.

    2005-11-01

    Heart sounds are associated with impulses of force acting on heart valves at the moment they close under the action of blood-pressure difference. A unified model for all the valves represents this impulse as an acoustic dipole. The near pressure field of this dipole creates a distribution of the normal velocity on the breast surface with features typical of auscultation practice: a pronounced localization of heart sound audibility areas, an individual area for each of the valves, and a noncoincidence of these areas with the projections of the valves onto the breast surface. In the framework of the dipole theory, the optimum size of the stethoscope’s bell is found and the spectrum of the heart sounds is estimated. The estimates are compared with the measured spectrum.

  10. [Spectral analysis and LDB based classification of heart sounds with mechanical prosthetic heart valves].

    Science.gov (United States)

    Zhang, Di; Wu, Yuequan; Yao, Jianping; Yang, Song; Du, Minghui

    2011-12-01

    Auscultation, the act of listening for heart sounds to aid in the diagnosis of various heart diseases, is a widely used efficient technique by cardiologists. Since the mechanical prosthetic heart valves are widely used today, it is important to develop a simple and efficient method to detect abnormal mechanical valves. The study on five different mechanical valves showed that only the case of perivalvular leakage could be detected by spectral estimation. Though it is possible to classify different mechanical valves by using time-frequency components of the signal directly, the recognition rate is merely 84%. However, with the improved local discriminant bases (LDB) algorithm to extract features from heart sounds, the recognition rate is 97.3%. Experimental results demonstrated that the improved LDB algorithm could improve classification rate and reduce computational complexity in comparison with original LDB algorithm.

  11. 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....... on the costs of healthcare use and sick leave among heart valve surgery patients over 12 months post surgery. METHODS: We conducted a nationwide survey on the CR participation of all patients having undergone valve surgery between 1 January 2011 and 30 June 2011 (n=667). Among the responders (n=500, 75......%), the resource use categories of primary and secondary healthcare, prescription medication and sick leave were analysed for CR participants (n=277) and non-participants (n=223) over 12 months. A difference-in-difference analysis was undertaken. All estimates were presented as the means per patient (95% CI) based...

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

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Young mee; Kim, Soo Hyun [Korea Institute of Science and Technology, Daejeon (Korea, Republic of)

    2010-10-15

    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

  13. 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...

  14. Effectiveness of dabigatran etexilate for thromboprophylaxis of mechanical heart valves.

    Science.gov (United States)

    McKellar, Stephen H; Abel, Stuart; Camp, Christopher L; Suri, Rakesh M; Ereth, Mark H; Schaff, Hartzell V

    2011-06-01

    Warfarin reduces risk of stroke in patients with mechanical heart valves but increases risk of hemorrhage and is difficult to use. Dabigatran etexilate, a new oral direct thrombin inhibitor, is safe and effective in reducing risk of stroke among patients with atrial fibrillation. No data exist in the setting of mechanical heart valves. We tested the hypothesis that dabigatran etexilate is as effective as heparin for thromboprophylaxis of mechanical valves in a porcine heterotopic aortic valve model. Thirty swine underwent implantation of modified bileaflet mechanical valved conduit bypassing the ligated, native descending thoracic aorta. Animals randomly received no anticoagulation (n = 10), enoxaparin 2 mg/kg subcutaneously twice daily (n = 10), or dabigatran etexilate 20 mg/kg orally twice daily. Primary end point was amount of valve thrombus at 30 days. Secondary end points included quantitative measurement of platelet deposition on valve prosthesis, thromboelastography, and hemorrhagic and embolic events. At 30 days, we observed 638 ± 895 mg thrombus in no anticoagulation group, 121 ± 128 mg in enoxaparin group, and 19 ± 31 mg in dabigatran etexilate group (P = .01 enoxaparin vs dabigatran etexilate). Fewer platelets were deposited on valves in dabigatran etexilate group (2.7 × 10(8)) than in enoxaparin group (1.8 × 10(9), P = .03). No major or occult hemorrhagic or embolic events were observed. By thromboelastographic analysis, dabigatran etexilate produced less prolongation of K value (P = .01) and less decreases in angle (P = .01) and maximum amplitude (P = .001) than enoxaparin. Dabigatran etexilate is as effective as enoxaparin for short-term thromboprophylaxis of mechanical valves. It prevents valve thrombus and platelet deposition at 30 days without increased adverse events. These promising results serve as a foundation for prospective clinical trials with dabigatran etexilate as an alternative to warfarin in patients with bileaflet

  15. 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

    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 Copenh......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...

  16. Measurements of flow past a bileaflet mechanical heart valve

    Science.gov (United States)

    Haya, Laura; Tavoularis, Stavros

    2013-11-01

    A bileaflet mechanical heart valve has been inserted in an axisymmetric model of the aorta within a mock circulation apparatus with physiological pressure and flow variations. The velocity field behind the valve has been measured with laser Doppler velocimetry and particle image velocimetry. The results closely match those reported by similar studies. A triple jet emanated from the valve's orifices and regions of reverse flow formed in the sinus region. Velocity fluctuations were greatest in the shear layers of the jets. The average r.m.s. streamwise velocity fluctuation over the turbulent period was 0.22 m/s; its maximum value was 0.53 m/s and occurred at the onset of deceleration. Measurements with the valve inserted in an anatomical model of the aorta are planned for the near future. The present and future measurements will be compared to determine the effects of the aorta anatomy on the characteristics of flow through bileaflet valves. In particular, measurements of the viscous and turbulent shear stresses will be analyzed to identify possible locations of blood element damage, and regions of recirculation and stagnation will be identified as locations favourable to thrombus growth. The effects of flows in branching arteries and valve orientation will also be investigated. Supported by NSERC.

  17. Robotic tissue tracking for beating heart mitral valve surgery.

    Science.gov (United States)

    Yuen, Shelten G; Vasilyev, Nikolay V; del Nido, Pedro J; Howe, Robert D

    2013-12-01

    The rapid motion of the heart presents a significant challenge to the surgeon during intracardiac beating heart procedures. We present a 3D ultrasound-guided motion compensation system that assists the surgeon by synchronizing instrument motion with the heart. The system utilizes the fact that certain intracardiac structures, like the mitral valve annulus, have trajectories that are largely constrained to translation along one axis. This allows the development of a real-time 3D ultrasound tissue tracker that we integrate with a 1 degree-of-freedom (DOF) actuated surgical instrument and predictive filter to devise a motion tracking system adapted to mitral valve annuloplasty. In vivo experiments demonstrate that the system provides highly accurate tracking (1.0 mm error) with 70% less error than manual tracking attempts. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Apixaban Versus Warfarin for Mechanical Heart Valve Thromboprophylaxis in a Swine Aortic Heterotopic Valve Model.

    Science.gov (United States)

    Lester, Patrick A; Coleman, Dawn M; Diaz, Jose A; Jackson, Tatum O; Hawley, Angela E; Mathues, Angela R; Grant, Brandon T; Knabb, Robert M; Ramacciotti, Eduardo; Frost, Charles E; Song, Yan; Wakefield, Thomas W; Myers, Daniel D

    2017-05-01

    Warfarin is the current standard for oral anticoagulation therapy in patients with mechanical heart valves, yet optimal therapy to maximize anticoagulation and minimize bleeding complications requires routine coagulation monitoring, possible dietary restrictions, and drug interaction monitoring. As alternatives to warfarin, oral direct acting factor Xa inhibitors are currently approved for the prophylaxis and treatment of venous thromboembolism and reduction of stroke and systemic embolization. However, no in vivo preclinical or clinical studies have been performed directly comparing oral factor Xa inhibitors such as apixaban to warfarin, the current standard of therapy. A well-documented heterotopic aortic valve porcine model was used to test the hypothesis that apixaban has comparable efficacy to warfarin for thromboprophylaxis of mechanical heart valves. Sixteen swine were implanted with a bileaflet mechanical aortic valve that bypassed the ligated descending thoracic aorta. Animals were randomized to 4 groups: control (no anticoagulation; n=4), apixaban oral 1 mg/kg twice a day (n=5), warfarin oral 0.04 to 0.08 mg/kg daily (international normalized ratio 2-3; n=3), and apixaban infusion (n=4). Postmortem valve thrombus was measured 30 days post-surgery for control-oral groups and 14 days post-surgery for the apixaban infusion group. Control thrombus weight (mean) was significantly different (1422.9 mg) compared with apixaban oral (357.5 mg), warfarin (247.1 mg), and apixiban 14-day infusion (61.1 mg; Pheart valves. Unlike warfarin, no adverse bleeding events were observed in any apixaban groups. © 2017 American Heart Association, Inc.

  19. [Indication and timing of heart valve surgery - summery of the European guidelines].

    Science.gov (United States)

    Sündermann, Simon H; Reser, Diana; Czerny, Martin; Falk, Volkmar

    2014-04-09

    Most common heart valve diseases in western industrialized nations are the aortic valve stenosis and the mitral valve regurgitation. More seldom are a regurgitation of the aortic valve and mitral valve stenosis. Even more seldom are heart valve diseases of the Tricuspid and the pulmonary valve. The only curative therapy in severe heart valve disease is a surgical intervention. The timing is crucial for the outcome. Especially in asymptomatic patients it's difficult to find the right point of time for intervention due to missing realization of the health status. In 2013, the European Association for Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC) published guidelines according to the therapy in heart valve disease. Here we want to summarize the recommendations of these guidelines in regards of timing of the surgical intervention.

  20. Rationale and design of the Edwards SAPIEN-3 periprosthetic leakage evaluation versus Medtronic CoreValve in transfemoral aortic valve implantation (ELECT) trial : A randomised comparison of balloon-expandable versus self-expanding transcatheter aortic valve prostheses.

    Science.gov (United States)

    Abawi, M; Agostoni, P; Kooistra, N H M; Samim, M; Nijhoff, F; Voskuil, M; Nathoe, H; Doevendans, P A; Chamuleau, S A; Urgel, K; Hendrikse, J; Leiner, T; Abrahams, A C; van der Worp, B; Stella, P R

    2017-05-01

    Periprosthetic aortic regurgitation (PPR) after transcatheter aortic valve implantation (TAVI) remains an important issue associated with impaired long-term outcomes. The current randomised study aims to evaluate potential differences between the balloon-expandable Edwards SAPIEN-3 and the self-expanding Medtronic CoreValve system with the main focus on post-TAVI PPR by means of novel imaging endpoints, and an additional focus on other clinical endpoints. The primary endpoint of this study is quantitative assessment of the severity of post-procedural PPR using cardiac magnetic resonance imaging. Several other novel imaging modalities (X-ray contrast angiography, echocardiography) are used as secondary imaging modalities for the assessment of PPR following TAVI. Secondary objectives of the study include clinical outcomes such as cerebral and kidney injury related to TAVI, and quality of life. The ELECT study is a single-centre, prospective, two-armed randomised controlled trial. For the purpose of this study, 108 consecutive adult patients suitable for transfemoral TAVI will be randomly allocated to receive the SAPIEN-3 (n = 54) or the CoreValve system (n = 54). The ELECT trial is the first randomised controlled trial to quantitatively compare the extent of post-TAVI PPR between the SAPIEN-3 and CoreValve. Furthermore, it will evaluate potential differences between the two prostheses with regard to mid-term clinical outcome and quality of life.

  1. In vivo behavior of epoxy-crosslinked porcine heart valve cusps and walls

    NARCIS (Netherlands)

    van Wachem, Pauline B.; Brouwer, Linda A.; Zeeman, R.; Dijkstra, Pieter J.; Feijen, Jan; Hendriks, Marc; Cahalan, Patrick T.; van Luyn, Marja J.A.

    2000-01-01

    Calcification limits the long-term durability of xenograft glutaraldehyde-crosslinked heart valves. In this study, epoxy-crosslinked porcine aortic valve tissue was evaluated after subcutaneous implantation in weanling rats. Non-crosslinked valves and valves crosslinked with glutaraldehyde or

  2. 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.

  3. In vivo behavior of epoxy-crosslinked porcine heart valve cusps and walls

    NARCIS (Netherlands)

    van Wachem, PB; Brouwer, LA; Zeeman, R; Dijkstra, PJ; Feijen, J; Hendriks, M; Cahalan, PT; van Luyn, MJA

    Calcification limits the long-term durability of xenograft glutaraldehyde-crosslinked heart valves. In this study, epoxy-crosslinked porcine aortic valve tissue was evaluated after subcutaneous implantation in weanling rats, Non-crosslinked valves and valves crosslinked with glutaraldehyde or

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

    Directory of Open Access Journals (Sweden)

    K. Yu. Klyshnikov

    2017-01-01

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

  5. Application of Hydrogels in Heart Valve Tissue Engineering

    Science.gov (United States)

    Zhang, Xing; Xu, Bin; Puperi, Daniel S.; Wu, Yan; West, Jennifer L.; Grande-Allen, K. Jane

    2015-01-01

    With an increasing number of patients requiring valve replacement, there is heightened interest in advancing heart valve tissue engineering (HVTE) to provide solutions to the many limitations of current surgical treatments. A variety of materials have been developed as scaffolds for HVTE including natural polymers, synthetic polymers, and decellularized valvular matrices. Among them, biocompatible hydrogels are generating growing interest. Natural hydrogels, such as collagen and fibrin, generally show good bioactivity, but poor mechanical durability. Synthetic hydrogels, on the other hand, have tunable mechanical properties; however, appropriate cell-matrix interactions are difficult to obtain. Moreover, hydrogels can be used as cell carriers when the cellular component is seeded into the polymer meshes or decellularized valve scaffolds. In this review, we discuss current research strategies for HVTE with an emphasis on hydrogel applications. The physicochemical properties and fabrication methods of these hydrogels, as well as their mechanical properties and bioactivities are described. Performance of some hydrogels including in vitro evaluation using bioreactors and in vivo tests in different animal models are also discussed. For future HVTE, it will be compelling to examine how hydrogels can be constructed from composite materials to replicate mechanical properties and mimic biological functions of the native heart valve. PMID:25955010

  6. Flow Through Deformable Orifice Diaphragms Used as Heart Valve Analogues

    Science.gov (United States)

    Amatya, Devesh; Longmire, Ellen

    2006-11-01

    Both hemodynamic and structural performance are important considerations in designing replacement heart valves. In this study, compression-molded silicone diaphragms of varying orifice and modulus are used as simplified heart valve analogues. Structural quantities such as diaphragm orifice area and deformation are quantified simultaneously with hemodynamic quantities (flow characteristics). Diaphragms are positioned downstream of a steady fully-developed pipe flow, and velocity fields are quantified both upstream and downstream of each diaphragm using particle image velocimetry (PIV). Diaphragm deformation is obtained from each image, while pressure drop across the diaphragm and volumetric flow rate are measured independently. The combined flow and structural data can be used to validate fluid-structure interaction codes suitable for biomedical applications. The bulk flow results will be compared against the existing hydraulic performance formula for rigid orifice diaphragms, and details of instantaneous flow fields will be presented.

  7. 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.

  8. Role of novel anticoagulants for patients with mechanical heart valves.

    Science.gov (United States)

    Forsberg, Peter; DeSancho, Maria T

    2014-11-01

    The introduction of the target-specific oral anticoagulants (TSOACs) has led to a major shift in the management of patients at risk for thrombosis. The landscape continues to evolve as the evidence regarding their efficacy and safety in various clinical situations emerges. Antithrombotic therapy for thromboprophylaxis in patients with mechanical heart valves is challenging. To date, the RE-ALIGN trial comparing dabigatran etexilate to warfarin is the only randomized controlled study in this patient population. The higher risk of thromboembolic and bleeding events in the group of patients who received dabigatran compared with warfarin reinforced current guidelines recommending against the use of TSOACs in patients with mechanical heart valves. However, additional studies are needed to find suitable alternatives to vitamin K antagonists in this unique patient population.

  9. Platelet activation through a Bi-leaflet mechanical heart valve

    Science.gov (United States)

    Hedayat, Mohammadali; Borazjani, Iman

    2016-11-01

    Platelet activation is one of the major drawbacks of the Mechanical Heart Valves (MHVs) which can increase the risk of thrombus formation in patients. The platelet activation in MHVs can be due to the abnormal shear stress during the systole, the backward leakage flow during the diastole, and the flow through the hinge region. We investigate the contribution of each of the above mechanism to the activation of platelets in MHVs by performing simulations of the flow through the MHV and in the hinge region. The large scale heart valve simulations are performed in a straight aorta using a sharp interface curvilinear immersed boundary method along with a strong-coupling algorithm under physiological flow conditions. In addition, in order to perform the simulation of hinge region the flow field boundary conditions are obtained from the largescale simulations during a whole cardiac cycle. In order to investigate the role of hinge flow on platelet activation in MHVs, a 23mm St. Jude Medical Regent valve hinge with three different gap sizes is tested along with different platelet activation models to ensure the consistency of our results with different activation models. We compare the platelet activation of the hinge region against the bulk of the flow during one cardiac cycle. This work is supported by the American Heart Association Grant 13SDG17220022, and the computational resources were partly provided by Center for Computational Research (CCR) at University at Buffalo.

  10. Patient-specific pediatric silicone heart valve models based on 3D ultrasound

    Science.gov (United States)

    Ilina, Anna; Lasso, Andras; Jolley, Matthew A.; Wohler, Brittany; Nguyen, Alex; Scanlan, Adam; Baum, Zachary; McGowan, Frank; Fichtinger, Gabor

    2017-03-01

    PURPOSE: Patient-specific heart and valve models have shown promise as training and planning tools for heart surgery, but physically realistic valve models remain elusive. Available proprietary, simulation-focused heart valve models are generic adult mitral valves and do not allow for patient-specific modeling as may be needed for rare diseases such as congenitally abnormal valves. We propose creating silicone valve models from a 3D-printed plastic mold as a solution that can be adapted to any individual patient and heart valve at a fraction of the cost of direct 3D-printing using soft materials. METHODS: Leaflets of a pediatric mitral valve, a tricuspid valve in a patient with hypoplastic left heart syndrome, and a complete atrioventricular canal valve were segmented from ultrasound images. A custom software was developed to automatically generate molds for each valve based on the segmentation. These molds were 3D-printed and used to make silicone valve models. The models were designed with cylindrical rims of different sizes surrounding the leaflets, to show the outline of the valve and add rigidity. Pediatric cardiac surgeons practiced suturing on the models and evaluated them for use as surgical planning and training tools. RESULTS: Five out of six surgeons reported that the valve models would be very useful as training tools for cardiac surgery. In this first iteration of valve models, leaflets were felt to be unrealistically thick or stiff compared to real pediatric leaflets. A thin tube rim was preferred for valve flexibility. CONCLUSION: The valve models were well received and considered to be valuable and accessible tools for heart valve surgery training. Further improvements will be made based on surgeons' feedback.

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

    Science.gov (United States)

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

    2014-01-01

    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. This design of the

  12. Human antibody recognition of xenogeneic antigens (NeuGc and Gal) on porcine heart valves: could genetically modified pig heart valves reduce structural valve deterioration?

    Science.gov (United States)

    Lee, Whayoung; Long, Cassandra; Ramsoondar, Jagdeece; Ayares, David; Cooper, David K C; Manji, Rizwan A; Hara, Hidetaka

    2016-09-01

    Glutaraldehyde-fixed bioprosthetic heart valves (GBHVs) derived from wild-type (WT, genetically unmodified) pigs are widely used clinically for heart valve replacement. There is evidence that their failure is related to an immune response. The use of valves from genetically engineered pigs that do not express specific pig antigens may prolong GBHV survival. Our aims were to determine (i) expression of Gal and NeuGc on heart (aortic and pulmonary) valves and pericardium of WT, α1,3-galactosyltransferase gene knockout (GTKO) and GTKO/N-glycolylneuraminic acid gene-knockout (GTKO/NeuGcKO) pigs in comparison with three different commercially available GBHVs and (ii) to determine human antibody binding to these tissues. Wild-type, GTKO/CD46, and GTKO/CD46/NeuGcKO pig valves and pericardium were tested (i) fresh and (ii) after fixation with glutaraldehyde (0.02%, 0.2%, 2%). Sections of GBHVs, fresh and fixed valves, and pericardium were stained for Gal and NeuGc expression, and for human IgM and IgG antibody binding. Gal and NeuGc expression was high on all GBHVs and WT pig valves/pericardium, but was absent after antigen-specific-knockout. There was no difference in antigen expression or antibody binding among WT aortic, pulmonary valves, and pericardium as well as GBHVs. Glutaraldehyde fixation did not alter expression of Gal or NeuGc. After incubation with human serum, human IgM and IgG bound to all GBHVs and WT pig valves/pericardium. Valves from GTKO/CD46 pigs and, particularly, GTKO/CD46/NeuGcKO pigs (with/without glutaraldehyde fixation) showed less IgM and IgG binding. Compared to WT pigs, GTKO/CD46/NeuGcKO pigs would be preferable sources of GBHVs, because the absence of Gal/NeuGc expression reduces human antibody binding. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. 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...... not been studied. This study investigated CR programmes for these patients and factors associated with referral and participation. DESIGN AND METHODS: We distributed two nationwide surveys: one to 37 hospitals and 98 municipalities and one to 742 consecutive patients undergoing heart valve surgery. Data......- and patient-level influenced uptake and included significant regional variation in referral pattern. Further research into the effect and organization of CR post heart valve surgery is needed....

  14. Matched Comparison of Self-Expanding Transcatheter Heart Valves for the Treatment of Failed Aortic Surgical Bioprosthesis: Insights From the Valve-in-Valve International Data Registry (VIVID).

    Science.gov (United States)

    Alnasser, Sami; Cheema, Asim N; Simonato, Matheus; Barbanti, Marco; Edwards, Jeremy; Kornowski, Ran; Horlick, Eric; Wijeysundera, Harindra C; Testa, Luca; Bedogni, Francesco; Amrane, Hafid; Walther, Thomas; Pelletier, Marc; Latib, Azeem; Laborde, Jean-Claude; Hildick-Smith, David; Kim, Won-Keun; Tchetche, Didier; Agrifoglio, Marco; Sinning, Jan-Malte; van Boven, Ad J; Kefer, Joëlle; Frerker, Christian; van Mieghem, Nicolas M; Linke, Axel; Worthley, Stephen; Asgar, Anita; Sgroi, Carmelo; Aziz, Mina; Danenberg, Haim D; Labinaz, Marino; Manoharan, Ganesh; Cheung, Anson; Webb, John G; Dvir, Danny

    2017-04-01

    Transcatheter valve-in-valve implantation is an established therapy for high-risk patients with failed surgical aortic bioprosthesis. There are limited data comparing outcomes of valve-in-valve implantation using different transcatheter heart valves (THV). Patients included in the Valve-in-Valve International Data registry (VIVID) and treated with self-expanding THV devices were analyzed using centralized core laboratory blinded to clinical events. St. Jude Medical Portico versus Medtronic CoreValve were compared in a 1:2 fashion after propensity score matching. A total of 162 patients, Portico- (n=54) and CoreValve- (n=108) based valve-in-valve procedures comprised the study population with no significant difference in baseline characteristics (age, 79±8.2 years; 60% women; mean STS [Society of Thoracic Surgery] score 8.1±5.5%). Postimplantation, CoreValve was associated with a larger effective orifice area (1.67 versus 1.31 cm2; P=0.001), lower mean gradient (14±7.5 versus 17±7.5 mm Hg; P=0.02), and lower core laboratory-adjudicated moderate-to-severe aortic insufficiency (4.2% versus 13.7%; P=0.04), compared with Portico. Procedural complications including THV malpositioning, second THV requirement, or coronary obstruction were not significantly different between the 2 groups. Survival and stroke rates at 30 days were similar, but overall mortality at 1 year was higher among patients treated with Portico compared with CoreValve (22.6% versus 9.1%; P=0.03). In this first matched comparison of THVs for valve-in-valve implantations, Portico and CoreValve demonstrated differences in postprocedural hemodynamics and long-term clinical outcomes. Although this could be related to THV design characteristics, the impact of other procedural factors cannot be excluded and require further evaluation. © 2017 American Heart Association, Inc.

  15. Genesis of the Mechanical Heart Valves' Ultrasonic Closing Clicks

    Science.gov (United States)

    Hasegawa, Jun; Kobayashi, Kenji

    A new in vitro experimental tool was developed to study the mechanism of the ultrasonic closing clicks' genesis of mechanical heart valves. Since the newly developed tester adopted compressed air flow directly instead of the blood analog fluid to drive the mechanical heart valve, it is not possibe to generate any cavitation. Closing clicks were measured with a small accelerometer at the surface of the valve holder made of silicone rubber. Ultrasonic closing clicks as well as audible closing clicks, similar to those measured clinically, could be observed using this setup. Thus, it was confirmed that the ultrasonic closing clicks can be generated without the existence of cavitation. Simultaneous measurements of the valve motion were made with a high-speed video camera, and the analysis of the video frames and clicks showed that higher frequency signal components of more than 50kHz could be generated only at the instant of the closure, which means the collision of the occluder with the housing. Eighteen miniature accelerometers with an area of one square millimeter were developed and stuck on the housing to monitor the distribution of the housing vibrations in detail, and it was found that the vibrations correspond to the ultrasonic closing clicks propagated from the valve stop: the collision point of the occluder with the housing. This fact indicated that the generation of ultrasonic closing clicks are limited to the small area of the collision. From those results, it was concluded that the major origin of the ultrasonic closing clicks' genesis should be the collision of the occluder with the housing.

  16. Tissue Heart Valve Replacement at BSMMU- Initial Experience with Two Cases

    Directory of Open Access Journals (Sweden)

    Rezwanul Hoque

    2010-07-01

    Full Text Available Research on prosthesis to replace diseased heart valves began almost simultaneously with mechanical valves which aredurable but with inherent thromboembolic complication requiring life-long anticoagulant therapy and tissue valves whichare more prone to structural failure but free from thromboembolic complication. Tissue valves are more useful in females ofreproductive age desiring a child, male patients older than 60 years of age and female patients over 55 years of age, patientshaving chronic liver disease, history of stroke, bleeding disorder and in presence of infective endocarditis. Gluteraldehydefixation at low pressure with removal of maximal amount of phospholipid have increased the durability of tissue valves inrecent years. Considering the better quality of life with tissue valve the trend is shifting towards using it more frequentlyaround the world. Recently two heart valve replacement operations using bovine perimount pericardial valve were done inthe department of cardiac surgery, BSMMU, one in aortic position another in mitral position, both in females of reproductiveage desiring children.The operations were technically demanding but the outcomes were uneventful. Tissue heart valvereplacement is a safe procedure and can be useful in female of child bearing age desiring children.Key Words: Tissue heart valve replacement; Aortic valve; Mitral valve; Bioprosthetic heart valves; Bovine perimountpericardial valve.DOI: 10.3329/bsmmuj.v3i1.5511BSMMU J 2010; 3(1: 27-30

  17. 75 FR 3238 - Draft Guidance for Industry and Food and Drug Administration Staff; Heart Valves...

    Science.gov (United States)

    2010-01-20

    ... Organization For Standardization (ISO), ISO 5840:2005, ``Cardiovascular Implants -- Cardiac Valve Prostheses'' (ISO 5840). Although the draft guidance document provides complementary information to ISO 5840:2005, the draft guidance document can also be used with other methods equivalent to ISO 5840:2005. II...

  18. Quadruple valve involvement in a patient with severe carcinoid heart disease.

    Science.gov (United States)

    Chiappini, Bruno; Noirhomme, Philippe; Verhelst, Robert; El Khoury, Gebrine

    2006-01-01

    We report on the case of a 48-year-old male patient suffering from a severe carcinoid heart disease with involvement of the four valves. The primary carcinoid tumor was diagnosed in the ileum. The patient developed a moderate stenosis and severe insufficiency of the tricuspid valve, a severe insufficiency of the pulmonary valve, and a moderate insufficiency of the mitral and aortic valves. Ultimately, a stentless pulmonary valve replacement was performed, as well as a tricuspid valve replacement with a pericardial prosthesis and aortic and mitral valve plasty. The patient recovered well and he was discharged from hospital on day 10.

  19. Fabrication of a novel hybrid heart valve leaflet for tissue engineering: an in vitro study.

    Science.gov (United States)

    Hong, Hao; Dong, Nianguo; Shi, Jiawei; Chen, Si; Guo, Chao; Hu, Ping; Qi, Hongxu

    2009-07-01

    The objective of this study was to fabricate biomatrix/polymer hybrid heart valve leaflet scaffolds using an electrospinning technique and seeded by mesenchymal stem cells. Mesenchymal stem cells were obtained from rats. Porcine aortic heart valve leaflets were decellularized, coated with basic fibroblast growth factor/chitosan/poly-4-hydroxybutyrate using an electrospinning technique, reseeded, and cultured over a time period of 14 days. Controls were reseeded and cultured over an equivalent time period. Specimens were examined biochemically, histologically, and mechanically. Recellularization of the hybrid heart valve leaflet scaffolds was significantly improved compared to controls. Biochemical and mechanical analysis revealed a significant increase of cell mass, 4-hydroxyproline, collagen, and strength in the hybrid heart valve leaflets compared to controls. This is the first attempt in tissue-engineered heart valves to fabricate hybrid heart valve leaflets using mesenchymal stem cells combined with a slow release technique and an electrospinning technique.

  20. Effects of Myocardial Contractility on Microemboli Production by Mechanical Heart Valves in a Bovine Model

    OpenAIRE

    Deklunder, Ghislaine; Lecroart, Jean-Louis; Conger, Jeff L.; Lapeyre, Didier; Gregoric, Igor; Rose, Harris; Tamez, Daniel; Frazier, O. H.

    2000-01-01

    Microemboli caused by mechanical heart valves have the potential to cause cerebrovascular events. We investigated the effects of myocardial contractility and heart rate on microemboli production in association with conventional and experimental mechanical heart valves implanted in the mitral position in a bovine model.

  1. Drug Therapy for Heart Valve Diseases

    Science.gov (United States)

    Borer, Jeffrey S.; Sharma, Abhishek

    2015-01-01

    Valvular heart diseases (VHDs) are progressive. When not caused by acute comorbidities they are generally characterized by long asymptomatic phases during which hemodynamic severity may progress leading to morbidity and mortality. Treatment depends on VHD type and severity but when severe and symptomatic, usually involves mechanical intervention. Asymptomatic patients, and those who lack objective descriptors associated with high risk, are closely observed clinically with optimization of associated cardiovascular risk factors until surgical indications develop. Though often prescribed based on theory, no rigorous evidence supports pharmacological therapy in most chronic situations though drugs may be appropriate in acute valvular diseases, or as a bridge to surgery in severely decompensated patients. Herein, we examine evidence supporting drug use for chronic VHDs. PMID:26371236

  2. Tgfβ-Smad and MAPK signaling mediate scleraxis and proteoglycan expression in heart valves.

    Science.gov (United States)

    Barnette, Damien N; Hulin, Alexia; Ahmed, A S Ishtiaq; Colige, Alain C; Azhar, Mohamad; Lincoln, Joy

    2013-12-01

    Mature heart valves are complex structures consisting of three highly organized extracellular matrix layers primarily composed of collagens, proteoglycans and elastin. Collectively, these diverse matrix components provide all the necessary biomechanical properties for valve function throughout life. In contrast to healthy valves, myxomatous valve disease is the most common cause of mitral valve prolapse in the human population and is characterized by an abnormal abundance of proteoglycans within the valve tri-laminar structure. Despite the clinical significance, the etiology of this phenotype is not known. Scleraxis (Scx) is a basic-helix-loop-helix transcription factor that we previously showed to be required for establishing heart valve structure during remodeling stages of valvulogenesis. In this study, we report that remodeling heart valves from Scx null mice express decreased levels of proteoglycans, particularly chondroitin sulfate proteoglycans (CSPGs), while overexpression in embryonic avian valve precursor cells and adult porcine valve interstitial cells increases CSPGs. Using these systems we further identify that Scx is positively regulated by canonical Tgfβ2 signaling during this process and this is attenuated by MAPK activity. Finally, we show that Scx is increased in myxomatous valves from human patients and mouse models, and overexpression in human mitral valve interstitial cells modestly increases proteoglycan expression consistent with myxomatous mitral valve phenotypes. Together, these studies identify an important role for Scx in regulating proteoglycans in embryonic and mature valve cells and suggest that imbalanced regulation could influence myxomatous pathogenesis. © 2013.

  3. Mechanism for cavitation in the mechanical heart valve with an artificial heart: nuclei and viscosity dependence.

    Science.gov (United States)

    Lee, Hwansung; Taenaka, Yoshiyuki; Kitamura, Soichiro

    2005-01-01

    Until now, we have estimated cavitation for mechanical heart valves (MHV) mounted in an electrohydraulic total artificial heart (EHTAH) with tap water. However, tap water at room temperature is not a proper substitute for blood at 37 degrees C. We therefore investigated fluid characterization in studies of MHV cavitation associated with the viscosity and nuclei content of a testing fluid. We used the Medtronic Hall valve mounted in the mitral position of the EHTAH. As testing fluids, tap water, distilled water, and glycerin solution were used. The valve-closing velocity, pressure-drop measurements, and a high-speed video camera were employed to determine the cavitation intensity in MHV. Most of the cavitation bubbles were observed at the edge of the valve stop. Our analysis of the results indicates that squeeze flow is the major cause of cavitation in the Medtronic Hall valve. The cavitation intensity increased with increases in the fluid viscosity and the valve-closing velocity. Even if cavitation intensity in glycerin solution was greater, the cavitation occurrence probability was less in glycerin solution than in tap water. Our results suggest that tap water contains particles that cause an increase in the cavitation occurrence probability. We conclude that cavitation intensity is greatly affected by the nuclei concentration in the fluid and the fluid viscosity.

  4. Automated control of the laser welding process of heart valve scaffolds

    Directory of Open Access Journals (Sweden)

    Weber Moritz

    2016-09-01

    Full Text Available Using the electrospinning process the geometry of a heart valve is not replicable by just one manufacturing process. To produce heart valve scaffolds the heart valve leaflets and the vessel have to be produced in separated spinning processes. For the final product of a heart valve they have to be mated afterwards. In this work an already existing three-axes laser was enhanced to laser weld those scaffolds. The automation control software is based on the robot operating system (ROS. The mechatronically control is done by an Arduino Mega. A graphical user interface (GUI is written with Python and Kivy.

  5. [History, present and future of biomaterials used for artificial heart valves].

    Science.gov (United States)

    Kostrzewa, Benita; Rybak, Zbigniew

    2013-01-01

    Artificial heart valves can be classified into mechanical and biological. We have three types of mechanical heart valves: caged ball, tilting disc and bileaflet. Mechanical heart valves are made from various materials. They may be produced from metals, ceramics and polymers, e.g.: stainless steel, titanium, silicone, pyrolytic carbon. Biological valves are made from synthetic components (e.g.: PTFE, Dacron) and materials of biological origin (e.g.: cow pericardium, pig heart valve). We have also identified transcatheter aortic valve implantation (TAVI). TAVI may be produced from metals, ceramics and polymers (e.g.: stainless steel, titanium, Dacron) and biological material (e.g.: pig heart valve). This paper describes advantages and disadvantages of different types of artificial heart valves. The lifespan of mechanical valves is 20-30 years and they can be used for patients of any age. Mechanical valves have also disadvantages--anticoagulants are required to prevent thrombosis. Biological valves are made from natural materials, so they do not require prolonged anticoagulation. Their lifetime is 10-15 years, so they are offered to patients over 40 years. Another problem is the occurrence of calcification.

  6. EXPERIENCE WITH IN ON-X PROSTHESIS IN HEART VALVE REPLACEMENT

    Directory of Open Access Journals (Sweden)

    M. A. Sazonenkov

    2010-01-01

    Full Text Available The prosthesis ON-X carcas has advantages in implantation commodity and safety, effective orifice area. We pe- sent results of this prosthesis usage during perioud of 2006–2009 years. This time 792 operations with AC were completed. In mitral position were implanted 132 (91,7% prostheses ON-X. Of them 80 (60,6% valves were sutured with complete or partial preservation of posterior leaflet and 26 (19,7% valves – with total MV preser- vation. In aortic position we implanted 76 (53,9% valves ON-X. Only 3 cases needed posterior aortoplasty for the N 23 prosthesis implantation. In perioperative and late postoperative periods we didn’t meet prostheses thrombosis or dysfunction. Reoperati- ons for high prosthesis gradients didn’t occur in postoperative period. Late postoperatively there were 3 (1,1% cases of embolic events related to the incorrect anticoagulant treatment. 

  7. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  9. Ministernotomy: A preliminary experience in heart valve surgery

    Directory of Open Access Journals (Sweden)

    Kovačević Pavle

    2011-01-01

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

  10. 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.

  11. Retrieval analysis of mechanical heart valves: impact on design and clinical practice

    NARCIS (Netherlands)

    Cromheecke, M. E.; Overkamp, P. J.; de Mol, B. A.; van Gaalen, G. L.; Becker, A. E.

    1998-01-01

    Explanted mechanical heart valves were examined nondestructively, and the findings were related to guidelines, technical reports, and other information to judge the risk of failure and its possible impact on valve design and clinical practice. Diagnoses for single valves could be made, but risks and

  12. Injectable tissue engineered pulmonary heart valve implantation into the pig model: A feasibility study.

    Science.gov (United States)

    Schlegel, Franziska; Salameh, Aida; Oelmann, Katja; Halling, Michelle; Dhein, Stefan; Mohr, Friedrich W; Dohmen, Pascal M

    2015-06-24

    Transcatheter pulmonary valve replacement is currently performed in clinical trials, however limited by the use of glutaraldehyde treated bioprostheses. This feasibility study was performed to evaluate delivery-related tissue distortion during implantation of a tissue engineered (TE) heart valves. The injectable TE heart valve was mounted on a self-expanding nitinol stent (n=7) and delivered into the pulmonary position of seven pigs, (weight 26 to 31 kg), performing a sternotomy or limited lateral thoracotomy. Prior to implantation, the injectable TE heart valve was crimped and inserted into an applicator. Positioning of the implants was guided by fluoroscopy and after carefully deployment angiographic examination was performed to evaluate the correct delivered position. Hemodynamic measurements were performed by epicardial echocardiography. Finally, the animals were sacrificed and the injectable TE heart valves were inspected by gross examination and histological examination. Orthotopic delivery of the injectable TE heart valves were all successful performed, expect in one were the valve migrated due to a discrepancy of pulmonary and injectable TE valve size. Angiographic evaluation (n=6) showed normal valve function, supported by epicardial echocardiography in which no increase flow velocity was measured, neither trans- nor paravalvular regurgitation. Histological evaluation demonstrated absence of tissue damage due to the delivery process. Transcatheter implantation of an injectable TE heart valve seems to be possible without tissue distortion due to the delivery system.

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

    Science.gov (United States)

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

    2014-03-01

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

  14. St Jude Epic heart valve bioprostheses versus native human and porcine aortic valves - comparison of mechanical properties.

    Science.gov (United States)

    Kalejs, Martins; Stradins, Peteris; Lacis, Romans; Ozolanta, Iveta; Pavars, Janis; Kasyanov, Vladimir

    2009-05-01

    The major problem with heart valve bioprostheses made from chemically treated porcine aortic valves is their limited longevity caused by gradual deterioration, which has a causal link with valve tissue mechanical properties. To our best knowledge, there are no published studies on the mechanical properties of modern, commercially available bioprostheses comparing them to native human valves. The objective of this study is to determine the mechanical properties of St Jude Epic bioprostheses and to compare them with native human and porcine aortic valves. Leaflets from eight porcine aortic valves and six Epic bioprostheses were analyzed using uni-axial tensile tests in radial and circumferential directions. Mechanical properties of human valves have been previously published by our group. Results are represented as mean values+/-S.D. Circumferential direction. Modulus of elasticity of Epic bioprostheses in circumferential direction at the level of stress 1.0 MPa is 101.99+/-58.24 MPa, 42.3+/-4.96 MPa for native porcine and 15.34+/-3.84 MPa for human aortic valves. Ultimate stress is highest for Epic bioprostheses 5.77+/-1.94 MPa, human valves have ultimate stress of 1.74+/-0.29 MPa and porcine 1.58+/-0.26 MPa. Ultimate strain in circumferential direction is highest for human valves 18.35+/-7.61% followed by 7.26+/-0.69% for porcine valves and 5.95+/-1.54% for Epic bioprostheses. Radial direction. Modulus of elasticity in radial direction is 9.18+/-1.81 MPa for Epic bioprostheses, 5.33+/-0.61 MPa for native porcine, and 1.98+/-0.15 MPa for human aortic valve leaflets. In the radial direction ultimate stress is highest for Epic bioprostheses 0.7+/-0.21 MPa followed by native porcine valves 0.55+/-0.11 MPa and 0.32+/-0.04 MPa for human valves. For human valves ultimate strain is 23.92+/-4.87%, for native porcine valves 8.57+/-0.8% and 7.92+/-1.74% for Epic bioprostheses. Epic bioprostheses have non-linear stress-strain behavior similar to native valve tissue, but they

  15. Hypoxia promotes primitive glycosaminoglycan-rich extracellular matrix composition in developing heart valves.

    Science.gov (United States)

    Amofa, Dorothy; Hulin, Alexia; Nakada, Yuji; Sadek, Hesham A; Yutzey, Katherine E

    2017-12-01

    During postnatal heart valve development, glycosaminoglycan (GAG)-rich valve primordia transform into stratified valve leaflets composed of GAGs, fibrillar collagen, and elastin layers accompanied by decreased cell proliferation as well as thinning and elongation. The neonatal period is characterized by the transition from a uterine environment to atmospheric O2, but the role of changing O2 levels in valve extracellular matrix (ECM) composition or morphogenesis is not well characterized. Here, we show that tissue hypoxia decreases in mouse aortic valves in the days after birth, concomitant with ECM remodeling and cell cycle arrest of valve interstitial cells. The effects of hypoxia on late embryonic valve ECM composition, Sox9 expression, and cell proliferation were examined in chicken embryo aortic valve organ cultures. Maintenance of late embryonic chicken aortic valve organ cultures in a hypoxic environment promotes GAG expression, Sox9 nuclear localization, and indicators of hyaluronan remodeling but does not affect fibrillar collagen content or cell proliferation. Chronic hypoxia also promotes GAG accumulation in murine adult heart valves in vivo. Together, these results support a role for hypoxia in maintaining a primitive GAG-rich matrix in developing heart valves before birth and also in the induction of hyaluronan remodeling in adults.NEW & NOTEWORTHY Tissue hypoxia decreases in mouse aortic valves after birth, and exposure to hypoxia promotes glycosaminoglycan accumulation in cultured chicken embryo valves and adult murine heart valves. Thus, hypoxia maintains a primitive extracellular matrix during heart valve development and promotes extracellular matrix remodeling in adult mice, as occurs in myxomatous disease. Copyright © 2017 the American Physiological Society.

  16. Bioactive porcine matrices in heart valve tissue engineering.

    Science.gov (United States)

    Somers, Pamela; de Somer, Filip; Cornelissen, Maria; Thierens, Hubert; Van Nooten, Guido

    2012-07-01

    Platelet gel (PG), a storage vehicle of growth factors, can be considered for the application of growth factors in combination with mesenchymal stem cells (MSCs) to accelerate tissue regeneration. Moreover, the addition of bioactive factors to porcine aortic valves could result in a more rapid repopulation. The study aim was to load acellular porcine aortic valve matrices with the PG-rich growth factors and to evaluate the effect on MSC repopulation. Ovine mesenchymal stem cells (oMSCs) were isolated from sheep bone marrow. Acellular porcine heart valve matrices (n = 3) were preloaded with heparin and incubated with the PG for 2 h. A quantitative sandwich enzyme immunoassay was used to examine the release of basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta) from the matrices, oMSC repopulation was stimulated by static and dynamic culture. The immunoassays revealed that heparin-preloaded PG-incubated matrices showed a sustained release of 56.28 pg/ml bFGF and 30.66 ng/ml TGF-beta1 after 24 h. Dynamic culture induced oMSC invasion in growth factor-loaded matrices. Cell density results showed that dynamic culture significantly enhanced the repopulation of growth factor-loaded matrices (75 +/- 21 cells/mm2) when compared to static culture (26 +/- 10 cells/mm2). The incubation of a porcine aortic valve matrix with a PG concentrate creates a bioactive matrix. However, further fine-tuning of the PG concentration is necessary to take full advantage of platelet growth factor interaction between cells and the extracellular matrix in order to optimize cellular repopulation.

  17. Magnesium Presence Prevents Removal of Antigenic Nuclear-Associated Proteins from Bovine Pericardium for Heart Valve Engineering.

    Science.gov (United States)

    Dalgliesh, Ailsa J; Liu, Zhi Zhao; Griffiths, Leigh G

    2017-07-01

    Current heart valve prostheses are associated with significant complications, including aggressive immune response, limited valve life expectancy, and inability to grow in juvenile patients. Animal derived "tissue" valves undergo glutaraldehyde fixation to mask tissue antigenicity; however, chronic immunological responses and associated calcification still commonly occur. A heart valve formed from an unfixed bovine pericardium (BP) extracellular matrix (ECM) scaffold, in which antigenic burden has been eliminated or significantly reduced, has potential to overcome deficiencies of current bioprostheses. Decellularization and antigen removal methods frequently use sequential solutions extrapolated from analytical chemistry approaches to promote solubility and removal of tissue components from resultant ECM scaffolds. However, the extent to which such prefractionation strategies may inhibit removal of antigenic tissue components has not been explored. We hypothesize that presence of magnesium in prefractionation steps causes DNA precipitation and reduces removal of nuclear-associated antigenic proteins. Keeping all variables consistent bar the addition or absence of magnesium (2 mM magnesium chloride hexahydrate), residual BP ECM scaffold antigenicity and removed antigenicity were assessed, along with residual and removed DNA content, ECM morphology, scaffold composition, and recellularization potential. Furthermore, we used proteomic methods to determine the mechanism by which magnesium presence or absence affects scaffold residual antigenicity. This study demonstrates that absence of magnesium from antigen removal solutions enhances solubility and subsequent removal of antigenic nuclear-associated proteins from BP. We therefore conclude that the primary mechanism of action for magnesium removal during antigen removal processes is avoidance of DNA precipitation, facilitating solubilization and removal of nuclear-associated antigenic proteins. Future studies are

  18. Polarized spatial frequency domain imaging of heart valve fiber structure

    Science.gov (United States)

    Goth, Will; Yang, Bin; Lesicko, John; Allen, Alicia; Sacks, Michael S.; Tunnell, James W.

    2016-03-01

    Our group previously introduced Polarized Spatial Frequency Domain Imaging (PSFDI), a wide-field, reflectance imaging technique which we used to empirically map fiber direction in porcine pulmonary heart valve leaflets (PHVL) without optical clearing or physical sectioning of the sample. Presented is an extended analysis of our PSFDI results using an inverse Mueller matrix model of polarized light scattering that allows additional maps of fiber orientation distribution, along with instrumentation permitting increased imaging speed for dynamic PHVL fiber measurements. We imaged electrospun fiber phantoms with PSFDI, and then compared these measurements to SEM data collected for the same phantoms. PHVL was then imaged and compared to results of the same leaflets optically cleared and imaged with small angle light scattering (SALS). The static PHVL images showed distinct regional variance of fiber orientation distribution, matching our SALS results. We used our improved imaging speed to observe bovine tendon subjected to dynamic loading using a biaxial stretching device. Our dynamic imaging experiment showed trackable changes in the fiber microstructure of biological tissue under loading. Our new PSFDI analysis model and instrumentation allows characterization of fiber structure within heart valve tissues (as validated with SALS measurements), along with imaging of dynamic fiber remodeling. The experimental data will be used as inputs to our constitutive models of PHVL tissue to fully characterize these tissues' elastic behavior, and has immediate application in determining the mechanisms of structural and functional failure in PHVLs used as bio-prosthetic implants.

  19. Tangible nanocomposites with diverse properties for heart valve application

    Science.gov (United States)

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

    2015-01-01

    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. PMID:27877785

  20. Aortic valve prosthesis-patient mismatch and exercise capacity in adult patients with congenital heart disease

    NARCIS (Netherlands)

    van Slooten, Ymkje J.; Melle, van Joost P.; Freling, Hendrik G.; Bouma, Berto J.; van Dijk, Arie P. J.; Jongbloed, Monique R. M.; Post, Martijn C.; Sieswerda, Gertjan T.; in 't Veld, Anna Huis; Ebels, Tjark; Voors, Adriaan A.; Pieper, Petronella G.

    Objectives To report the prevalence of aortic valve prosthesis patient mismatch (PPM) in an adult population with congenital heart disease (CHD) and its impact on exercise capacity. Adults with congenital heart disease (ACHD) with a history of aortic valve replacement may outgrow their prosthesis

  1. Conceptual model for early health technology assessment of current and novel heart valve interventions

    NARCIS (Netherlands)

    S.A. Huygens (Simone); M.P.M.H. Rutten-van Mölken (Maureen); J.A. Bekkers (Jos); A.J.J.C. Bogers (Ad); C.V.C. Bouten (Carlijn); S.A.J. Chamuleau (Steven); DeJaegere, P.P.T. (Peter P. T.); A.P. Kappetein (Arie Pieter); J. Kluin (Jolanda); N.M. van Mieghem (Nicolas); M. Versteegh (Michel); M. Witsenburg (Maarten); J.J.M. Takkenberg (Hanneke)

    2016-01-01

    textabstractAdvances in the field of heart valve interventions, like tissue-engineered heart valves (TEHV). Prior to introduction in clinical practice, it is essential to perform early health technology assessment. We aim to develop a conceptual model (CM) that can be used to investigate the

  2. Conceptual model for early health technology assessment of current and novel heart valve interventions

    NARCIS (Netherlands)

    Huygens, Simone A.; Rutten-van Mölken, Maureen P. M. H.; Bekkers, Jos A.; Bogers, Ad J. J. C.; Bouten, Carlijn V. C.; Chamuleau, Steven A. J.; de Jaegere, Peter P. T.; Kappetein, Arie Pieter; Kluin, Jolanda; van Mieghem, Nicolas M. D. A.; Versteegh, Michel I. M.; Witsenburg, Maarten; Takkenberg, Johanna J. M.

    2016-01-01

    The future promises many technological advances in the field of heart valve interventions, like tissue-engineered heart valves (TEHV). Prior to introduction in clinical practice, it is essential to perform early health technology assessment. We aim to develop a conceptual model (CM) that can be used

  3. Conceptual model for early health technology assessment of current and novel heart valve interventions

    NARCIS (Netherlands)

    Huygens, Simone A.; Rutten-VanMölken, Maureen P M H; Bekkers, Jos A.; Bogers, Ad J J C; Bouten, Carlijn V C; Chamuleau, Steven A J|info:eu-repo/dai/nl/236454161; DeJaegere, Peter P T; Pieter Kappetein, Arie; Kluin, Jolanda; Vanmieghem, Nicolas M D A; Versteegh, Michel I M; Witsenburg, Maarten; Takkenberg, Johanna J M

    2016-01-01

    Advances in the field of heart valve interventions, like tissue-engineered heart valves (TEHV). Prior to introduction in clinical practice, it is essential to perform early health technology assessment. We aim to develop a conceptual model (CM) that can be used to investigate the performance and

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

    DEFF Research Database (Denmark)

    Kikkenborg Berg, Selina; 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. 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

  6. The role of collagen cross-links in biomechanical behavior of human aortic heart valve leaflets - Relevance for tissue engineering

    NARCIS (Netherlands)

    Balguid, A.; Rubbens, M.P.; Mol, A.; Bank, R.A.; Bogers, A.J.J.C.; Kats, J.P. van; Mol, B.A.J.M. de; Baaijens, F.P.T.; Bouten, C.V.C.

    2007-01-01

    A major challenge in tissue engineering of functional heart valves is to determine and mimic the dominant tissue structures that regulate heart valve function and in vivo survival. In native heart valves, the anisotropic matrix architecture assures sustained and adequate functioning under

  7. Differences in left ventricular remodelling in patients with aortic stenosis treated with transcatheter aortic valve replacement with corevalve prostheses compared to surgery with porcine or bovine biological prostheses

    DEFF Research Database (Denmark)

    Ngo, Thuc Anh; Hassager, Christian; Thyregod, Hans Gustav Hørsted

    2018-01-01

    Aims: Patients with severe aortic stenosis (AS) can be considered for treatment with either transcatheter (TAVR) or surgical aortic valve replacement (SAVR). The purpose of this study was to compare left ventricular (LV) remodeling in patients with AS after treatment with TAVR or SAVR. Methods an...

  8. Analysis of velocity fluctuations downstream of a bileaflet mechanical heart valve

    Science.gov (United States)

    Forleo, Marcio; Dasi, Lakshmi

    2010-11-01

    Bileaflet mechanical heart valves are widely used to replace diseased aortic heart valves. The stresses induced by the rich and unsteady non-physiological flow structures have been the focus to evaluate red blood cells damage and platelet activation, develop flow control strategies, or improve valve designs. In this study, we analyzed the flow fields obtained downstream of a bileaflet mechanical heart valve using time-resolved particle image velocimetry under pulsatile and steady flow conditions. Our study demonstrates the rich dynamics downstream of the valve and weighs the relevance of unsteady effects vs inertia effects on the different flow structures. Power spectrum analyses of the turbulent fluctuations highlight the highly anisotropic influence and the limited applicability of classical self-similar turbulence theory in describing the small-scale structures in the immediate vicinity of the valve.

  9. A review of fluid-structure interaction simulations of prosthetic heart valves.

    Science.gov (United States)

    Borazjani, Iman

    2015-01-01

    Dysfunctional natural heart valves are replaced with prosthetic heart valves through surgery. However, prosthetic valves are far from ideal. Bioprosthetic heart valves (BHVs) suffer from early calcification and structural damages. Mechanical heart valves (MHVs) are durable but highly thrombogenic and require lifelong anticoagulant treatment. These complications are believed to be related to nonphysiologic flow patterns created by these valves. Fluid-structure interaction (FSI) simulations are essential in revealing the hemodynamics of these valves. By combining the three-dimensional (3D) flow field obtained from realistic FSI simulations with platelet activation models, nonphysiologic flow patterns can be identified. In this review paper, state-of-the-art methods for simulating FSI in heart valves are reviewed, and the flow physics uncovered by FSI simulations are discussed. Finally, the limitations of current methods are discussed, and future research directions are proposed as follows: (1) incorporation of realistic, image-based ventricle and atrium geometries; (2) comparing MHV and BHV under similar conditions to identify nonphysiologic flow patterns; (3) developing better models to estimate platelet activation potential to be incorporated into the simulations; and (4) identifying the optimum placement of the valves in both mitral and aortic positions.

  10. A new concept in the sewing rings for mechanical heart valves.

    Science.gov (United States)

    Kurian, Mathew V; Umasankar, Payanam R; Sabareeswaran, Arumugam; Shenoy, Sachin J; Subban, Vijayakumar; Joseph, Mathew K

    2012-08-01

    Valve-associated complications challenge the quality of life and longevity after heart valve replacement. Inappropriate healing may be a contributing factor. To evaluate a new design mechanical heart valve in an animal model. The new valve was fabricated by substituting the sewing ring with an inbuilt suture ridge and an overlying fabric flap. It improved the effective orifice area. Animal experiments were performed on pigs to compare this valve with standard valve models. The animals were kept on dual antiplatelet drugs. Six of the 8 test animals survived the observation period of 140 days compared to 2 of the 6 controls. Among the test valves, one had thrombosis and 3 had significant tissue hyperplasia, whereas 5 control valves had thrombosis associated with significant tissue hyperplasia. Three test valves had paravalvular defects compared to none in the control group. Histology showed good tissue incorporation of the fabric flap of the test valves, whereas the control valves had tissue infiltration limited to the peripheral fabric layer of the sewing ring. The new valve has improved effective orifice area, and the animal study showed better survival, good healing, and a lower incidence of thrombosis and tissue hyperplasia.

  11. Cost-utility analysis of cardiac rehabilitation after conventional heart valve surgery versus usual care

    DEFF Research Database (Denmark)

    Hansen, Tina Birgitte; Zwisler, Ann Dorthe; Kikkenborg Berg, Selina

    2017-01-01

    Background While cardiac rehabilitation in patients with ischaemic heart disease and heart failure is considered cost-effective, this evidence may not be transferable to heart valve surgery patients. The aim of this study was to investigate the cost-effectiveness of cardiac rehabilitation following...... heart valve surgery. Design We conducted a cost-utility analysis based on a randomised controlled trial of 147 patients who had undergone heart valve surgery and were followed for 6 months. Methods Patients were randomised to cardiac rehabilitation consisting of 12 weeks of physical exercise training...... rehabilitation compared to usual care is at minimum 75%, driven by a tendency towards costs savings. Conclusions Cardiac rehabilitation after heart valve surgery may not have improved health-related quality of life in this study, but is likely to be cost-effective for society, outweighing the extra costs...

  12. Observation and quantification of cavitation on a mechanical heart valve with an electro-hydraulic total artificial heart.

    Science.gov (United States)

    Lee, H; Taenaka, Y

    2006-03-01

    In previous studies, we investigated the cavitation phenomenon in a mechanical heart valve using an electro-hydraulic total artificial heart. With this system, a 50% glycerin solution kept at 37 degrees C was used as the working fluid. We reported that most of the cavitation bubbles were observed near the valve stop and were caused by the squeeze flow. However, in these studies, the effect of the partial pressure of CO(2) on the mechanical heart valve cavitation was neglected. In this study, in order to investigate the effect of the partial pressure of CO(2) on mechanical heart valve cavitation using an electro-hydraulic total artificial heart, we controlled the partial pressure of the CO(2) in vitro. A 25-mm Medtronic Hall valve was installed in the mitral position of an electro-hydraulic total artificial heart. In order to quantify the mechanical heart valve cavitation, we used a high-speed camera. Even though cavitation intensity slightly increased with increases in the PCO(2) at heart rates of 60, 70 and 100 bpm, throughout the experiment, there was no significant difference between the PCO(2) and cavitation intensity.

  13. Platelet activation of mechanical versus bioprosthetic heart valves during systole.

    Science.gov (United States)

    Hedayat, Mohammadali; Asgharzadeh, Hafez; Borazjani, Iman

    2017-05-03

    Thrombus formation is a major concern for recipients of mechanical heart valves (MHVs), which requires them to take anticoagulant drugs for the rest of their lives. Bioprosthetic heart valves (BHVs) do not require life-long anticoagulant therapy but deteriorate after 10-15years. The thrombus formation is initiated by the platelet activation which is thought to be mainly generated in MHVs by the flow through the hinge and the leakage flow during the diastole. However, our results show that the activation in the bulk flow during the systole phase might play an essential role as well. This is based on our results obtained by comparing the thrombogenic performance of a MHV and a BHV (as control) in terms of shear induced platelet activation under exactly the same conditions. Three different mathematical activation models including linear level of activation, damage accumulation, and Soares model are tested to quantify the platelet activation during systole using the previous simulations of the flow through MHV and BHV in a straight aorta under the same physiologic flow conditions. Results indicate that the platelet activation in the MHV at the beginning of the systole phase is slightly less than the BHV. However, at the end of the systole phase the platelet activation by the bulk flow for the MHV is several folds (1.41, 5.12, and 2.81 for linear level of activation, damage accumulation, and Soares model, respectively) higher than the BHV for all tested platelet activation models. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Form Follows Function: Advances in Trilayered Structure Replication for Aortic Heart Valve Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Dan T. Simionescu

    2012-01-01

    Full Text Available Tissue engineering the aortic heart valve is a challenging endeavor because of the particular hemodynamic and biologic conditions present in the native aortic heart valve. The backbone of an ideal valve substitute should be a scaffold that is strong enough to withstand billions of repetitive bending, flexing and stretching cycles, while also being slowly degradable to allow for remodeling. In this review, we highlight three overlooked aspects that might influence the long term durability of tissue engineered valves: (i replication of the native valve trilayered histoarchitecture, (ii duplication of the three-dimensional shape of the valve, (iii and cell integration efforts focused on getting the right number and type of cells to the right place within the valve structure and driving them towards homeostatic maintenance of the valve matrix. We propose that the trilayered structure in the native aortic valve that includes a middle spongiosa layer cushioning the motions of the two external fibrous layers should be our template for creation of novel scaffolds with improved mechanical durability. Furthermore, since cells adapt to micro-loads within the valve structure, we believe that interstitial cell remodeling of the valvular matrix will depend on the accurate replication of the structures and loads, resulting in successful regeneration of the valve tissue and extended durability.

  15. Mechanisms of function and disease of natural and replacement heart valves.

    Science.gov (United States)

    Schoen, Frederick J

    2012-01-01

    Over the past several decades, there has been substantial progress toward understanding the mechanisms of heart valve function and dysfunction. This review summarizes an evolving conceptual framework of heart valve functional structure, developmental biology, and pathobiology and explores the implications of key insights. I emphasize: (a) valve cell and extracellular matrix biology and the impact of biomechanical factors on function, homeostasis, environmental adaptation, and key pathological processes; (b) the role of developmental processes, valvular cell behavior, and extracellular matrix remodeling in congenital and acquired valve abnormalities; and (c) the cell/matrix biology of degeneration in replacement tissue valves. I also summarize how these considerations may ultimately inform the potential for prevention and treatment of major diseases and potentially therapeutic regeneration of the cardiac valves. Recent advances and opportunities for research and clinical translation are highlighted.

  16. On the open/close performance of prosthetic heart valves at high frequencies

    Science.gov (United States)

    Beltran, A.; Zenit, R.

    2013-11-01

    We report experimental observations of the performance of mechanical and biological prosthetic heart valves. The valves are mounted in a test circular channel conected to a flow system that emulates accelerated human-like conditions. The flow is generated by a high frequencie pulsative pump (in the range of 7 to 18 Hz). The objective of the investigation is to find the treshold conditions for which the open/close performance fails. Preliminary results show that for the mechanical valve the failure starts at 436 pulses/min, while for the biological valve, it starts a failing performance is observed for frequencies higher that 462 pulses/min. Even though these values are far from the heart rate in the human body, we use these measurements to further understand the structure-fluid interaction mechanics of the flow through heart valves.

  17. 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.

  18. Valve repair improves central sleep apnea in heart failure patients with valvular heart diseases.

    Science.gov (United States)

    Abe, Hidetoshi; Takahashi, Masafumi; Yaegashi, Hironobu; Eda, Seiichiro; Kitahara, Hiroto; Tsunemoto, Hideo; Kamikozawa, Mamoru; Koyama, Jun; Yamazaki, Kyohei; Ikeda, Uichi

    2009-11-01

    Recent studies suggest that treatment of heart failure (HF) could improve cardiac function and sleep apnea syndrome (SAS), but it is unknown how cardiac surgery may affect SAS in HF patients. Relationships between HF with valvular heart diseases and 2 types of SAS (obstructive sleep apnea (OSA) and central sleep apnea (CSA)) were examined. The effects of valve repair surgery on OSA and CSA was also investigated. Polysomnography, echocardiography and right cardiac catheterization were used to study 150 severe HF patients with mitral valvular and/or aortic valvular diseases. Significant associations between SAS and age, gender, body mass index, or hypertension were observed. The value of the CSA-apnea index (AI) was significantly correlated with pulmonary capillary wedge pressure (PCWP) and mean pulmonary artery pressure (PAP). These associations were not identified for OSA-AI. Valve repair surgery was used to treat 74 patients with severe SAS. The treatment led to a significant improvement in PCWP and mean PAP, and CSA-AI, but not in OSA-AI. These findings suggest close associations between CSA and cardiac function in HF patients with valvular heart diseases. Furthermore, improvement of cardiac function with valvular surgery reduces the severity of CSA in HF patients with valvular heart diseases.

  19. Durability of pericardial versus porcine bioprosthetic heart valves.

    Science.gov (United States)

    Grunkemeier, Gary L; Furnary, Anthony P; Wu, YingXing; Wang, Lian; Starr, Albert

    2012-12-01

    To compare the probability, and modes, of explantation for Carpentier-Edwards pericardial versus porcine valves. Our porcine series began in 1974 and our pericardial series in 1991, with annual prospective follow-up. We used the Kaplan-Meier method and Cox regression for estimation and analysis of patient mortality, and the cumulative incidence function and competing risks regression for estimation and analysis of valve durability. Through the end of 2010, we had implanted 506 porcine and 2449 pericardial aortic valves and 181 porcine and 163 pericardial mitral valves. The corresponding total and maximum follow-up years were 3471 and 24, 11,517 and 18, 864 and 22, and 645 and 9. The corresponding probabilities (cumulative incidence function) of any valve explant were 7%, 8%, 22%, and 8%, and of explant for structural valve deterioration were 4%, 5%, 16%, and 5% at 15 years for the first 3 series and at 8 years for the fourth (pericardial mitral valve) series. Using competing risks regression for structural valve deterioration explant, with age, gender, valve size, and concomitant coronary bypass surgery as covariates, a slight (subhazard ratio, 0.79), but nonsignificant, protective effect was found for the pericardial valve in the aortic position and a greater (subhazard ratio, 0.31) and almost significant (P = .08) protective effect of the pericardial valve in the mitral position. Leaflet tear was responsible for 61% of the structural valve deterioration explants in the porcine series and 46% in the pericardial series. Using competing risks regression, the pericardial valve had a subhazard ratio for structural valve deterioration explant of less than 1 in both positions, approaching statistical significance in the mitral position. The mode of structural valve deterioration was predominantly leaflet tear for porcine valves and fibrosis/calcification for pericardial valves. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc

  20. Anticoagulant independent mechanical heart valves: viable now or still a distant holy grail.

    Science.gov (United States)

    Chaux, Aurelio; Gray, Richard J; Stupka, Jonathan C; Emken, Michael R; Scotten, Lawrence N; Siegel, Rolland

    2016-12-01

    Valvular heart disease remains a large public health problem for all societies; it attracts the attention of public health organizations, researchers and governments. Valve substitution is an integral part of the treatment for this condition. At present, the choice of valve prosthesis is either tissue or mechanical. Tissue valves have become increasingly popular in spite of unresolved problems with durability, hemodynamics, cost and need for anticoagulation therapy. As a consequence, mechanical valve innovation has virtually ceased; the last successful mechanical design is 25 years old. We postulate that with improved technology, knowledge and experience gained over the last quarter century, the best possible solution to the problem of valve substitution can be achieved with a mechanical valve that is anticoagulant independent, durable, hemodynamically and cost efficient. At present, it is possible to design, test and produce a valve that can accomplish these goals.

  1. Twenty years' single-center experience with mechanical heart valves: a critical review of anticoagulation policy.

    Science.gov (United States)

    Van Nooten, Guido J; Caes, Frank; François, Katrien; Van Bellleghem, Yves; Bové, Thierry; Vandenplas, Guy; Taeymans, Yves

    2012-01-01

    Since January 1990, a variety of mechanical valves (St. Jude Medical, CarboMedics, ATS Medical) have been implanted routinely at the authors' institution. The study aim was to analyze, retrospectively, the 20-year clinical results of those mechanical valves, and to challenge the anticoagulation policy employed over the years. Between January 1990 and December 2008, a total of 2,108 mechanical valves was inserted into 1,887 consecutive patients (1,346 aortic, 725 mitral, 27 tricuspid, 10 pulmonary). The mean age of the patients was 63 +/- 13.2 years, and the majority (61%) were males. Preoperatively, 71% the patients were in NYHA class > or = III (average 3.01). The most frequent comorbidities included: atrial fibrillation (n = 594), coronary disease (n = 567) and diabetes (n = 398). The follow up (99% complete) totaled 13,721 patient-years (pt-yr), and ranged from 12 to 241 months (average 84 months). In-hospital mortality was 5.2% (n = 98, 14 valve-related). Of the 629 late deaths, the majority were cardiac (n = 276). Survival (Kaplan-Meier estimation) was significantly better for aortic valve patients compared to mitral or multiple valve replacement (Mantel-Cox, p valve thrombosis 0.31, thromboembolism 1.08, and bleeding 0.91. However, as repeated events occurred in several patients, the hazard function was not constant. Multivariate analysis (Cox regression model) showed age > 70 years (p or = III (p II as significant risk factors for thromboembolism, while long-acting coumadin and NYHA class > II were significant risk factors for bleeding. This 20-year experience demonstrated excellent clinical outcomes for patients with mechanical prostheses, with no valve structural failure and an acceptable incidence of adverse events. INR values between 2-2.5 for aortic valve patients, and 3-3.5 for mitral valve patients, yielded the fewest major adverse events.

  2. Effect of the sinus of valsalva on the closing motion of bileaflet prosthetic heart valves.

    Science.gov (United States)

    Ohta, Y; Kikuta, Y; Shimooka, T; Mitamura, Y; Yuhta, T; Dohi, T

    2000-04-01

    Conventional bileaflet prosthetic mechanical heart valves close passively with backflow. Naturally, the valve has problems associated with closure, such as backflow, water hammer effect, and fracture of the leaflet. On the other hand, in the case of the natural aortic valve, the vortex flow in the sinus of Valsalva pushes the leaflet to close, and the valve starts the closing motion earlier than the prosthetic valve as the forward flow decelerates. This closing mechanism is thought to decrease backflow at valve closure. In this study, we propose a new bileaflet mechanical valve resembling a drawbridge in shape, and the prototype valve was designed so that the leaflet closes with the help of the vortex flow in the sinus. The test valve was made of aluminum alloy, and its closing motion was compared to that of the CarboMedics (CM) valve. Both valves were driven by a computer controlled hydraulic mock circulator and were photographed at 648 frames/s by a high speed charge-coupled device (CCD) camera. Each frame of the valve motion image was analyzed with a personal computer, and the opening angles were measured. The flow rate was set as 5.0 L/min. The system was pulsed with 70 bpm, and the systolic/diastolic ratio was 0.3. Glycerin water was used as the circulation fluid at room temperature, and polystyrene particles were used to visualize the streamline. The model of the sinus of Valsalva was made of transparent silicone rubber. As a result, high speed video analysis showed that the test valve started the closing motion 41 ms earlier than the CM valve, and streamline analysis showed that the test valve had a closing mechanism similar to the natural one with the effect of vortex flow. The structure of the test valve was thought to be effective for soft closure and could solve problems associated with closure.

  3. Living nano-micro fibrous woven fabric/hydrogel composite scaffolds for heart valve engineering.

    Science.gov (United States)

    Wu, Shaohua; Duan, Bin; Qin, Xiaohong; Butcher, Jonathan T

    2017-03-15

    Regeneration and repair of injured or diseased heart valves remains a clinical challenge. Tissue engineering provides a promising treatment approach to facilitate living heart valve repair and regeneration. Three-dimensional (3D) biomimetic scaffolds that possess heterogeneous and anisotropic features that approximate those of native heart valve tissue are beneficial to the successful in vitro development of tissue engineered heart valves (TEHV). Here we report the development and characterization of a novel composite scaffold consisting of nano- and micro-scale fibrous woven fabrics and 3D hydrogels by using textile techniques combined with bioactive hydrogel formation. Embedded nano-micro fibrous scaffolds within hydrogel enhanced mechanical strength and physical structural anisotropy of the composite scaffold (similar to native aortic valve leaflets) and also reduced its compaction. We determined that the composite scaffolds supported the growth of human aortic valve interstitial cells (HAVIC), balanced the remodeling of heart valve ECM against shrinkage, and maintained better physiological fibroblastic phenotype in both normal and diseased HAVIC over single materials. These fabricated composite scaffolds enable the engineering of a living heart valve graft with improved anisotropic structure and tissue biomechanics important for maintaining valve cell phenotypes. Heart valve-related disease is an important clinical problem, with over 300,000 surgical repairs performed annually. Tissue engineering offers a promising strategy for heart valve repair and regeneration. In this study, we developed and tissue engineered living nano-micro fibrous woven fabric/hydrogel composite scaffolds by using textile technique combined with bioactive hydrogel formation. The novelty of our technique is that the composite scaffolds can mimic physical structure anisotropy and the mechanical strength of natural aortic valve leaflet. Moreover, the composite scaffolds prevented the

  4. Use of low molecular weight heparin in pregnant women with mechanical heart valves.

    Science.gov (United States)

    Yinon, Yoav; Siu, Samuel C; Warshafsky, Chelsie; Maxwell, Cynthia; McLeod, Anne; Colman, Jack M; Sermer, Mathew; Silversides, Candice K

    2009-11-01

    There are a number of different anticoagulation options for pregnant women with mechanical heart valves. The purpose of this study was to examine maternal thromboembolic complications in women with mechanical valves treated with low-molecular weight heparin (LMWH) throughout pregnancy. This was a substudy of a larger prospective cohort study of pregnant women with heart disease followed from 1998 to 2008. All pregnant women with mechanical left-sided valves who were treated with LMWH throughout pregnancy were included. Maternal thromboembolic events were defined as valve thrombosis, need for valve replacement, or stroke during pregnancy or postpartum (up to 6 months). Twenty-three pregnancies (17 women) occurred in women treated with LMWH and low-dose aspirin: 15 in women with mechanical mitral valves, 9 in women with mechanical aortic valves, and 1 in a woman with both. There was 1 maternal thromboembolic event (4%), which resulted in maternal and fetal death. Five women (22%) developed other adverse cardiac events during pregnancy. Nine pregnancies (43%) had fetal or neonatal adverse events, 5 of which had favorable outcomes. Three pregnancies were complicated by postpartum hemorrhage. In conclusion, carefully monitored LMWH may be a suitable anticoagulation strategy in pregnant women with mechanical heart valves who are unwilling to use warfarin. However, this group of women remains at risk for maternal cardiac and fetal complications. The occurrence of valve thrombosis resulting in maternal death despite therapeutic anti-Xa levels highlights current limitations with anticoagulation in this population.

  5. Pregnancy with prosthetic heart valves - 30 years' nationwide experience in Denmark

    DEFF Research Database (Denmark)

    Sillesen, Martin; Hjortdal, Vibeke; Vejlstrup, Niels

    2011-01-01

    Pregnancy in women with prosthetic heart valves remains a risk factor for both mother and fetus, but unselected and unbiased outcome and complication data remain scarce. We analyzed nationwide outcome data from 1977 to 2007 for all pregnancies in women with prosthetic valves....

  6. 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.

  7. Morphological assessment of sucrose preservation for porcine heart valves.

    OpenAIRE

    Drury, P J; Olsen, E G; Ross, D N

    1982-01-01

    Porcine aortic valves stored in various concentrations of sucrose (50-80%) for up to 52 weeks were examined both histologically and by electron microscopy. The valves were compared with porcine aortic valves stored in a nutrient and antibiotic medium for 12 weeks. Overall preservation was better in those porcine valves stored in sucrose solution than in nutrient and antibiotic medium, the best preservation being in 50% sucrose. Despite wide separation of collagen at that concentration seen on...

  8. Decreasing warfarin sensitivity during the first three months after heart valve surgery : Implications for dosing

    NARCIS (Netherlands)

    Meijer, K.; Kim, Y. -K.; Schulman, S.

    Introduction: Vitamin K antagonists are prescribed to prevent thromboembolic complications after heart valve surgery. In our experience, patients often show a progressive decrease in sensitivity to warfarin after surgery making it difficult to reach and maintain a therapeutic International

  9. Fabrication of a novel hybrid scaffold for tissue engineered heart valve.

    Science.gov (United States)

    Hong, Hao; Dong, Nianguo; Shi, Jiawei; Chen, Si; Guo, Chao; Hu, Ping; Qi, Hongxu

    2009-10-01

    The aim of this study was to fabricate biomatrix/polymer hybrid scaffolds using an electrospinning 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 reseeded and cultured over an equivalent time period. Specimens of each group were examined histologically (hematoxylin-eosin [HE] staining, immunohistostaining, and scanning electron microscopy), biochemically (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 (Phybrid scaffolds to increase the mechanical 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.

  10. Current Progress in Tissue Engineering of Heart Valves: Multiscale Problems, Multiscale Solutions

    Science.gov (United States)

    Cheung, Daniel Y; Duan, Bin; Butcher, Jonathan T.

    2016-01-01

    Introduction Heart valve disease is an increasingly prevalent and clinically serious condition. There are no clinically effective biological diagnostics or treatment strategies. The only recourse available is replacement with a prosthetic valve, but the inability of these devices to grow or respond biologically to their environments necessitates multiple resizing surgeries and life-long coagulation treatment, especially in children. Tissue engineering has a unique opportunity to impact heart valve disease by providing a living valve conduit, capable of growth and biological integration. Areas covered This review will cover current tissue engineering strategies in fabricating heart valves and their progress towards the clinic, including molded scaffolds using naturally-derived or synthetic polymers, decellularization, electrospinning, 3D bioprinting, hybrid techniques, and in vivo engineering. Expert opinion While much progress has been made to create functional living heart valves, a clinically viable product is not yet realized. The next leap in engineered living heart valves will require a deeper understanding of how the natural multi-scale structural and biological heterogeneity of the tissue ensures its efficient function. Related, improved fabrication strategies must be developed that can replicate this de novo complexity, which is likely instructive for appropriate cell differentiation and remodeling whether seeded with autologous stem cells in vitro or endogenously recruited cells. PMID:26027436

  11. Elimination of alpha-gal xenoreactive epitope: alpha-galactosidase treatment of porcine heart valves.

    Science.gov (United States)

    Choi, Sun-Young; Jeong, Hee-Jin; Lim, Hong-Gook; Park, Seong-Sik; Kim, Soo-Hwan; Kim, Yong Jin

    2012-05-01

    Porcine heart valves are among the most widely used tissue valves in clinical heart valve implantation. However, immunologic responses have been implicated as potential causes of the limited durability of xenograft heart valves. The study aim was to determine the effectiveness of alpha-galactosidase treatment used to degrade the major xenoreactive antigens found in xenograft heart valves. Fresh porcine heart valves and pericardium treated with alpha-galactosidase were studied to evaluate the xenoreactive galactose (alpha1,3) galactose (alpha-gal) antigen. Removal of the alpha-gal epitope from the porcine heart valve was monitored via 3,3'-diaminobenzidine staining intensity, while the removal of alpha-gal from N-glycans on porcine heart valves treated with recombinant alpha-galactosidase was determined either qualitatively or quantitatively by mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The porcine pericardium was used for monitoring the change in mechanical properties after alpha-galactosidase treatment. In addition, the biomechanical modification property of collagen fiber rearrangement on tissue was assessed using transmission electron microscopy (TEM). Following a 24-h incubation at pH 7.2, 4 degrees C, employing 0.1 U/ml of Bacteroides thetaiotaomicron-derived recombinant alpha-galactosidase, the enzyme effectively removed the alpha-gal epitopes expressed on porcine heart valves. The identification type of alpha-gal N-glycan on fresh aortic valve, aortic wall, pulmonary valve, and pulmonary wall was 7.1%, 10.3%, 6% and 8%, respectively. In the presence of alpha-galactosidase treatment, alpha-gal-containing N-glycans were converted into alpha-gal-negative N-glycans. Likewise, alpha-gal-containing N-glycans were not detected when MALDI-TOF MS quantitative analysis was used. Furthermore, no significant difference was observed in the mechanical properties and findings from TEM in alpha

  12. Hybrid textile heart valve prosthesis: preliminary in vitro evaluation.

    Science.gov (United States)

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

    2016-09-22

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

  13. Management dilemmas in patients with mechanical heart valves and warfarin-induced major bleeding.

    Science.gov (United States)

    Panduranga, Prashanth; Al-Mukhaini, Mohammed; Al-Muslahi, Muhanna; Haque, Mohammed A; Shehab, Abdullah

    2012-03-26

    Management of warfarin-induced major bleeding in patients with mechanical heart valves is challenging. There is vast controversy and confusion in the type of treatment required to reverse anticoagulation and stop bleeding as well as the ideal time to restart warfarin therapy safely without recurrence of bleeding and/or thromboembolism. Presently, the treatments available to reverse warfarin-induced bleeding are vitamin K, fresh frozen plasma, prothrombin complex concentrates and recombinant activated factor VIIa. Currently, vitamin K and fresh frozen plasma are the recommended treatments in patients with mechanical heart valves and warfarin-induced major bleeding. The safe use of prothrombin complex concentrates and recombinant activated factor VIIa in patients with mechanical heart valves is controversial and needs well-designed clinical studies. With regard to restarting anticoagulation in patients with warfarin-induced major bleeding and mechanical heart valves, the safe period varies from 7-14 d after the onset of bleeding for patients with intracranial bleed and 48-72 h for patients with extra-cranial bleed. In this review article, we present relevant literature about these controversies and suggest recommendations for management of patients with warfarin-induced bleeding and a mechanical heart valve. Furthermore, there is an urgent need for separate specific guidelines from major associations/ professional societies with regard to mechanical heart valves and warfarin-induced bleeding.

  14. 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.

  15. Heart valve scaffold fabrication: Bioinspired control of macro-scale morphology, mechanics and micro-structure.

    Science.gov (United States)

    D'Amore, Antonio; Luketich, Samuel K; Raffa, Giuseppe M; Olia, Salim; Menallo, Giorgio; Mazzola, Antonino; D'Accardi, Flavio; Grunberg, Tamir; Gu, Xinzhu; Pilato, Michele; Kameneva, Marina V; Badhwar, Vinay; Wagner, William R

    2018-01-01

    Valvular heart disease is currently treated with mechanical valves, which benefit from longevity, but are burdened by chronic anticoagulation therapy, or with bioprosthetic valves, which have reduced thromboembolic risk, but limited durability. Tissue engineered heart valves have been proposed to resolve these issues by implanting a scaffold that is replaced by endogenous growth, leaving autologous, functional leaflets that would putatively eliminate the need for anticoagulation and avoid calcification. Despite the diversity in fabrication strategies and encouraging results in large animal models, control over engineered valve structure-function remains at best partial. This study aimed to overcome these limitations by introducing double component deposition (DCD), an electrodeposition technique that employs multi-phase electrodes to dictate valve macro and microstructure and resultant function. Results in this report demonstrate the capacity of the DCD method to simultaneously control scaffold macro-scale morphology, mechanics and microstructure while producing fully assembled stent-less multi-leaflet valves composed of microscopic fibers. DCD engineered valve characterization included: leaflet thickness, biaxial properties, bending properties, and quantitative structural analysis of multi-photon and scanning electron micrographs. Quasi-static ex-vivo valve coaptation testing and dynamic organ level functional assessment in a pressure pulse duplicating device demonstrated appropriate acute valve functionality. Copyright © 2017. Published by Elsevier Ltd.

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

    Science.gov (United States)

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

    2013-01-01

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

  17. 3D velocity field characterization of prosthetic heart valve with two different valve testers by means of stereo-PIV.

    Science.gov (United States)

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

    2015-01-01

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

  18. Degradation effect of diepoxide fixation on porcine endogenous retrovirus DNA in heart valves: molecular aspects.

    Science.gov (United States)

    Cyganek-Niemiec, Aleksandra; Strzalka-Mrozik, Barbara; Pawlus-Lachecka, Lucyna; Wszolek, Jolanta; Adamska, Jolanta; Kudrjavtseva, Julia; Zhuravleva, Irina; Kimsa, Malgorzata; Okla, Hubert; Kimsa, Magdalena; Gudek, Agnieszka; Mazurek, Urszula

    2012-01-01

    Xenotransplantations of porcine cells, tissues, and organs involve a risk of zoonotic viral infections in recipients, including by porcine endogenous retroviruses (PERVs), which are embedded the genome of all pigs. An appropriate preparation of porcine heart valves for transplantation can prevent retroviral infection. Therefore, the present study focuses on the effect of epoxy compounds and glutaraldehyde on the PERV presence in porcine heart valves prepared for clinical use. Porcine aortic heart valves were fixed with ethylene glycol diglycidyl ether (EDGE) at 5 °C and 25 °C as well as with glutaraldehyde (GA) for 4 weeks. Salting out was used to isolate genomic DNA from native as well as EDGE- and GA-fixed fragments of valves every week. Quantification of PERV-A, PERV-B, and PERV-C DNA was performed by real-time quantitative polymerase chain reaction (QPCR). All subtypes of PERVs were detected in native porcine aortic heart valves. The reduction of the PERV-A, PERV-B, and PERV-C DNA copy numbers was observed in the heart valves which were EDGE-fixed at both temperatures, and in GA-fixed ones in the following weeks. After 7 and 14 days of EDGE cross-linking, significant differences between the investigated temperatures were found for the number of PERV-A and PERV-B copies. PERV DNA was completely degraded within the first week of EDGE fixation at 25 °C. EDGE fixation induces complete PERV genetic material degradation in porcine aortic heart valves. This suggests that epoxy compounds may be alternatively used in the preparation of bioprosthetic heart valves in future.

  19. Optimal Anticoagulation for Pregnant Women with Mechanical Heart Valves.

    Science.gov (United States)

    D'Souza, Rohan; Silversides, Candice K; McLintock, Claire

    2016-10-01

    The prothrombotic state of pregnancy increases the risk of thromboembolic complications and death in women with mechanical heart valves (MHVs). Although it is accepted that these women must be on therapeutic anticoagulation throughout pregnancy, competing maternal and fetal risks, as well as the lack of high-quality data from prospective studies, make the choice of the optimal method of anticoagulation challenging. Vitamin K antagonists (VKAs) are associated with fewer maternal complications, but conversely also the lowest live birth rates as well as warfarin-related embryopathy and fetopathy. Low-molecular-weight heparin (LMWH) does not cross the placenta and is associated with fewer fetal risks but more maternal complications. Sequential treatment involving VKAs in the second and third trimesters and either low-molecular-weight or unfractionated heparin in the first trimester, although appealing is still associated with maternal complications, especially around the time of bridging. As absolute equipoise of maternal versus fetal wellbeing is unlikely, patient preferences should be considered in decision making. A multidisciplinary team including hematologists, cardiologists, obstetric physicians, and high-risk obstetricians with expertise in the management of pregnant women with cardiac disease is required to optimize outcomes. Prospective studies are needed to determine the anticoagulant regimen for women with MHVs that provides optimal and acceptable maternal and fetal outcomes. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  20. Galnt1 is required for normal heart valve development and cardiac function.

    Directory of Open Access Journals (Sweden)

    E Tian

    Full Text Available Congenital heart valve defects in humans occur in approximately 2% of live births and are a major source of compromised cardiac function. In this study we demonstrate that normal heart valve development and cardiac function are dependent upon Galnt1, the gene that encodes a member of the family of glycosyltransferases (GalNAc-Ts responsible for the initiation of mucin-type O-glycosylation. In the adult mouse, compromised cardiac function that mimics human congenital heart disease, including aortic and pulmonary valve stenosis and regurgitation; altered ejection fraction; and cardiac dilation, was observed in Galnt1 null animals. The underlying phenotype is aberrant valve formation caused by increased cell proliferation within the outflow tract cushion of developing hearts, which is first detected at developmental stage E11.5. Developing valves from Galnt1 deficient animals displayed reduced levels of the proteases ADAMTS1 and ADAMTS5, decreased cleavage of the proteoglycan versican and increased levels of other extracellular matrix proteins. We also observed increased BMP and MAPK signaling. Taken together, the ablation of Galnt1 appears to disrupt the formation/remodeling of the extracellular matrix and alters conserved signaling pathways that regulate cell proliferation. Our study provides insight into the role of this conserved protein modification in cardiac valve development and may represent a new model for idiopathic valve disease.

  1. Supercritical Carbon Dioxide–Based Sterilization of Decellularized Heart Valves

    Directory of Open Access Journals (Sweden)

    Ryan S. Hennessy, MD

    2017-02-01

    Full Text Available Summary: Sterilization of grafts is essential. Supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide techniques were compared for impact on sterility and mechanical integrity of porcine decellularized aortic valves. Ethanol-peracetic acid– and supercritical carbon dioxide–treated valves were found to be sterile using histology, microbe culture, and electron microscopy assays. The cusp tensile properties of supercritical carbon dioxide–treated valves were higher compared with valves treated with other techniques. Superior sterility and integrity was found in the decellularized valves treated with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues. Key Words: decellularized, decontamination, heart valve, tensile properties, tissue engineering

  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. A newly designed jellyfish valve for an artificial heart blood pump.

    Science.gov (United States)

    Imachi, K; Fujimasa, I; Mabuchi, K; Chinzei, T; Abe, Y; Maeda, K; Imanishi, K; Kouno, A; Ono, T; Atsumi, K

    1988-01-01

    Bjork-Shiley and Hall valves used in most artificial heart blood pumps have often induced problems, which include 1) An expensive valve must be used even when the AH is used for only a few days, 2) Ring thrombus was often formed at the interface between the valve ring and blood pump, seamless fabrication was not possible, and 3) Mechanical failure often occurred. To improve these circumstances, a new jellyfish valve was designed and manufactured. The valve has a simple structure: The center of a thin circular polyurethane membrane is fixed on a polyurethane base plate, which has many holes or slits to reduce flow resistance and help hold the membrane during the diastolic phase. In a mock circulation study, the valve displayed performance similar to the Bjork-Shiley valve. A small amount of regurgitant flow was observed at valve closure, in comparison with the Bjork-Shiley valve. It was recognized in the flow visualization study that the central region of the membrane was washed out well by the flapping of the membrane. This jellyfish valve is promising for use in a AH blood pump.

  4. Fabrication of a jellyfish valve for use in an artificial heart.

    Science.gov (United States)

    Imachi, K; Mabuchi, K; Chinzei, T; Abe, Y; Imanishi, K; Yonezawa, T; Kouno, A; Ono, T; Nozawa, H; Isoyama, T

    1992-01-01

    For a valve to be fabricated seamlessly into an artificial heart (AH) blood pump, a jellyfish valve has been developed, in which a thin membrane is fixed at the center of a valve seat having several spokes to protect against prolapse of the membrane. The valve is superior in performances to a Björk-Shiley valve, and reveals good blood compatibility. The valve would be very useful not only for AH animal study, but for future clinical use in infants to adults. Several institutions are already trying the valve. In this paper, the fabrication of the jellyfish valve is introduced, and in vitro and in vivo results summarized. A computer aided design (CAD) system was developed to cut a male wax mold of the valve seat. The input parameters to the CAD are diameter, height, thickness of rim, number of spokes, width and thickness of spokes, etc. Jellyfish valves with diameters of 4 to 27 mm have already been fabricated for many types of AHs and assist pumps.

  5. Mitral implant of the Inovare transcatheter heart valve in failed surgical bioprostheses: a novel alternative for valve-in-valve procedures.

    Science.gov (United States)

    Gaia, Diego Felipe; Braz, Ademir Massarico; Simonato, Matheus; Dvir, Danny; Breda, João Roberto; Ribeiro, Gustavo Calado; Ferreira, Carolina Baeta; Souza, José Augusto Marcondes; Buffolo, Enio; Palma, José Honório

    2017-04-01

    Reoperative procedure for the treatment of a failed mitral bioprosthesis is associated with considerable risk. In some cases, mortality is high and might contraindicate the benefit of the procedure. The minimally invasive valve-in-valve (ViV) transcatheter mitral valve implant offers an alternative less-invasive approach, reducing morbidity and mortality. The objective of this paper was to evaluate the mitral ViV approach using the Braile Inovare prosthesis. The transcatheter balloon-expandable Braile Inovare prosthesis was used in 12 cases. Procedures were performed in a hybrid operating room, under fluoroscopic and echocardiographic control. Through left minithoracotomy, the prostheses were implanted through the cardiac apex. Serial echocardiographic and clinical examinations were performed. Follow-up varied from 1 to 30 months. A total of 12 transapical mitral ViV procedures were performed. Patients had a mean age of 61.6 ± 9.9 years and 92% were women. Mean logistic EuroSCORE was 20.1%. Successful valve implantation was possible in all cases. In one case, a right lateral thoracotomy was performed for the removal of an embolized prosthesis. There was no operative mortality. Thirty-day mortality was 8.3%. Ejection fraction was preserved after the implant (66.7%; 64.8%; P  = 0.3). The mitral gradient showed a significant reduction (11 mmHg; 6 mmHg; P  < 0.001). Residual mitral regurgitation was not present. There was no left ventricular outflow tract obstruction. The mitral ViV implant in a failed bioprosthesis is an effective procedure. This possibility might alter prosthesis selection in the future initial surgical prosthesis selection, favouring bioprostheses. Further large trials should explore its safety.

  6. Surface heparin treatment of the decellularized porcine heart valve: Effect on tissue calcification.

    Science.gov (United States)

    Yang, Min; Lin, Yang-Hua; Shi, Wei-Ping; Shi, Hong-Can; Gu, Y John; Shu, Yu-Sheng

    2017-02-01

    Tissue calcification is a major cause of failure of bioprosthetic heart valves. Aim of this study was to examine whether surface heparin treatment of the decellularized porcine heart valve reduces tissue calcification. Fresh porcine aortic heart valves were dissected as tissue discs and divided into four groups. Group A: controls without treatment, Group B: decellularization only, Group C: decellularization and glutaraldehyde cross-linking, Group D: decellularization and glutaraldehyde cross-linking followed by surface heparin treatment. After implantation in New Zealand White rabbits for 60 days, the explanted heart valve discs from the different study groups underwent a series of histological examinations as well as determination of calcium content by the methyl thyme phenol blue colorimetric method. Results of the explanted heart valve discs for the Von Kossa staining demonstrated that in Group A the heart valve tissue was the most severely stained with black color, whereas in Group D there was hardly any area that was stained black after implantation indicating the least tissue calcification. Furthermore, the inflammatory cells identified by the Hematoxylin-eosin staining appeared to be the least in Group D. The average tissue calcium content was highest in Group A (0.197 ± 0.115 μmol mg-1 ), modest in Group B (0.113 ± 0.041 μmol mg-1 ), and Group C (0.089 ± 0.049 μmol mg-1 ), and the lowest in Group D (0.019 ± 0.019 μmol mg-1 , p porcine heart valve in a rabbit intramuscular implantation model. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 400-405, 2017. © 2015 Wiley Periodicals, Inc.

  7. Comparative classification of thrombotic formations on bileaflet mechanical heart valves by phonographic analysis.

    Science.gov (United States)

    Romata, Clemens; Susin, Francesca Maria; Cambi, Andrea; Tarzia, Vincenzo; Pengo, Vittorio; Gerosa, Gino; Bagno, Andrea

    2011-06-01

    Haemodynamic performance of bileaflet mechanical heart valves can be severely affected by the formation of thrombotic deposits. Hence, early detection of thrombi is fundamental for a prompt diagnosis and adequate therapy. This article aims at designing a novel diagnostic and prognostic tool able to detect valvular thrombosis at early stages of formation, i.e., before the appearance of critical symptoms in patients who can be effectively treated by pharmacological therapy, preventing re-operation. This approach relies on the acquisition of the acoustic signals produced by mechanical heart valves in the closing phase; the corresponding power spectra are then analysed by means of artificial neural networks trained to identify the presence of thrombi and classify their occurrence. Five commercial bileaflet mechanical heart valves were investigated in vitro in a Sheffield Pulse Duplicator; for each valve six functional conditions were considered, each corresponding to a risk class for patients (one normofunctioning and five thrombosed): they have been simulated by placing artificial deposits of increasing weight and different shape on the valve leaflet and on the annular housing; the case of one completely blocked leaflet was also investigated. These six functional conditions represent risk classes: they were examined under various hydrodynamic regimes. The acoustic signals produced by the valves were acquired by means of a phonocardiographic apparatus, then analysed and classified. The ability to detect and classify thrombotic formations on mechanical valve leaflet would allow ranking patients by assigning them to one of the six risk classes, helping clinicians in establish adequate therapeutic approaches.

  8. 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...

  9. Joint Modelling of Longitudinal and Survival Data with Applications in Heart Valve Data

    NARCIS (Netherlands)

    E-R. Andrinopoulou (Eleni-Rosalina)

    2014-01-01

    markdownabstract__Abstract__ The heart is one of the most important organs in the entire human body. Specifically, it is a pump composed of muscle which pumps blood throughout the blood vessels to various parts of the body by repeated rhythmic contractions. The four heart valves determine the

  10. Double orifice mitral valve in rheumatic heart disease.

    Science.gov (United States)

    Choudhury, Partha P; Chaturvedi, Vivek

    2014-01-01

    A 55-year-old female, presented to our outpatient department with complaints of dyspnea on exertion, NYHA grade II for 7 years, which had progressed to NYHA Grade III in the past 6 months. An echocardiogram done showed severe mitral stenosis with mitral valve fused in the middle to create an appearance of 2 separate valves (complete bridge type) with 2 separate turbulent jets of flow across these valves. No other congenital anomaly was seen. Due to presence of severe subvalvular disease, she was sent for elective mitral valve replacement. This case demonstrates that a careful analysis of the subvalvular apparatus of the mitral valve is needed before making a decision for definitive treatment of this condition.

  11. 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

    2010-01-01

    Heart Rate Variability in Cavalier King Charles Spaniels with Different Degree of Myxomatous Mitral Valve Disease Rasmussen, C.E. 1, Falk, T. 1, Zois, N.E. 1, Moesgaard, S.G. 1, Häggström, J. 2, Pedersen, H.D. 3 and Olsen, L.H1. 1Department of Basic Animal and Veterinary Sciences, Faculty of Life...... 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...... into 4 groups: 1) no or minimal mitral regurgitation (MR) (MR jet=15% of the left atrial area) and no murmur, 2) mild MR (20%50%) and no clinical signs of heart failure, 4) left atrium to aortic root ratio >1.5, clinical signs of heart failure and furosemide...

  12. [A case with tricuspid valve brucella endocarditis presenting with acute right heart failure].

    Science.gov (United States)

    Yazıcı, Hüseyin Uğur; Mert, Kadir Uğur; Senol, Utku; Ulus, Taner

    2012-06-01

    Although the presence of brucella endocarditis is encountered rarely, it is the most fetal complication of brucellosis, which is shown to affect the aortic valve primarily and the mitral valve secondarily. Involvement of the tricuspid valve is extremely rare. A 62-year-old female was admitted with complaints of fever, fatigue, difficulty in breathing, and swellings in her legs. A transthoracic echocardiogram was performed since acute right heart failure was considered due to her symptoms. The echocardiogram showed enlarged right heart chambers, serious tricuspid valve insufficiency, and a mass on the tricuspid valve compatible with a vegetation moving in and out of the right ventricle. Although no growths were observed in the blood culture, antibody titration for brucellosis was found to be 1/640 (+) in the serological examination. The patient was diagnosed with brucella endocarditis and placed on doxycycline, rifampicin, and ceftriaxone treatment for eight weeks. At the end of the eight-week treatment, the symptoms of right heart failure receded and the patient recovered from the endocarditis. Tricuspid valve brucella endocarditis should be considered in patients suffering from acute right heart failure accompanied by systemic infection findings since brucellosis is presently endemic in Turkey.

  13. The Inter-Relationship of Periostin, TGFβ, and BMP in Heart Valve Development and Valvular Heart Diseases

    Directory of Open Access Journals (Sweden)

    Simon J. Conway

    2011-01-01

    Full Text Available Recent studies have suggested an important role for periostin and transforming growth factor beta (TGFβ and bone morphogenetic protein (BMP ligands in heart valve formation and valvular heart diseases. The function of these molecules in cardiovascular development has previously been individually reviewed, but their association has not been thoroughly examined. Here, we summarize the current understanding of the association between periostin and TGFβ and BMP ligands, and discuss the implications of this association in the context of the role of these molecules in heart valve development and valvular homeostasis. Information about hierarchal connections between periostin and TGFβ and BMP ligands in valvulogenesis will increase our understanding of the pathogenesis, progression, and medical treatment of human valve diseases.

  14. The inter-relationship of periostin, TGF beta, and BMP in heart valve development and valvular heart diseases.

    Science.gov (United States)

    Conway, Simon J; Doetschman, Thomas; Azhar, Mohamad

    2011-07-28

    Recent studies have suggested an important role for periostin and transforming growth factor beta (TGF beta) and bone morphogenetic protein (BMP) ligands in heart valve formation and valvular heart diseases. The function of these molecules in cardiovascular development has previously been individually reviewed, but their association has not been thoroughly examined. Here, we summarize the current understanding of the association between periostin and TGF beta and BMP ligands, and discuss the implications of this association in the context of the role of these molecules in heart valve development and valvular homeostasis. Information about hierarchal connections between periostin and TGF beta and BMP ligands in valvulogenesis will increase our understanding of the pathogenesis, progression, and medical treatment of human valve diseases.

  15. The Inter-Relationship of Periostin, TGFβ, and BMP in Heart Valve Development and Valvular Heart Diseases

    Science.gov (United States)

    Conway, Simon J.; Doetschman, Thomas; Azhar, Mohamad

    2011-01-01

    Recent studies have suggested an important role for periostin and transforming growth factor beta (TGFβ) and bone morphogenetic protein (BMP) ligands in heart valve formation and valvular heart diseases. The function of these molecules in cardiovascular development has previously been individually reviewed, but their association has not been thoroughly examined. Here, we summarize the current understanding of the association between periostin and TGFβ and BMP ligands, and discuss the implications of this association in the context of the role of these molecules in heart valve development and valvular homeostasis. Information about hierarchal connections between periostin and TGFβ and BMP ligands in valvulogenesis will increase our understanding of the pathogenesis, progression, and medical treatment of human valve diseases. PMID:21805020

  16. Supercritical carbon dioxide-based sterilization of decellularized heart valves.

    Science.gov (United States)

    Hennessy, Ryan S; Jana, Soumen; Tefft, Brandon J; Helder, Meghana R; Young, Melissa D; Hennessy, Rebecca R; Stoyles, Nicholas J; Lerman, Amir

    2017-02-01

    The goal of this research project encompasses finding the most efficient and effective method of decellularized tissue sterilization. Aortic tissue grafts have been utilized to repair damaged or diseased valves. Although, the tissues for grafting are collected aseptically, it does not eradicate the risk of contamination nor disease transfer. Thus, sterilization of grafts is mandatory. Several techniques have been applied to sterilize grafts; however, each technique shows drawbacks. In this study, we compared several sterilization techniques: supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide for impact on the sterility and mechanical integrity of porcine decellularized aortic valves. Valve sterility was characterized by histology, microbe culture, and electron microscopy. Uniaxial tensile testing was conducted on the valve cusps along their circumferential orientation to study these sterilization techniques on their integrity. Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile. The tensile strength of supercritical carbon dioxide treated valves (4.28 ± 0.22 MPa) was higher to those valves treated with electrolyzed water, gamma radiation, ethanol-peracetic acid and hydrogen peroxide (1.02 ± 0.15, 1.25 ± 0.25, 3.53 ± 0.41 and 0.37 ± 0.04 MPa, respectively). Superior sterility and integrity were found in the decellularized porcine aortic valves with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues. Sterilization of grafts is essential. Supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide techniques were compared for impact on sterility and mechanical integrity of porcine decellularized aortic valves. Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile using histology, microbe

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

    Science.gov (United States)

    Jahnavi, S; Kumary, T V; Bhuvaneshwar, G S; Natarajan, T S; Verma, R S

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Prosthetic valves in adult patients with congenital heart disease : Rationale and design of the Dutch PROSTAVA study

    NARCIS (Netherlands)

    Freling, H. G.; van Slooten, Y. J.; van Melle, J. P.; Mulder, B. J. M.; van Dijk, A. P. J.; Hillege, H. L.; Post, M. C.; Sieswerda, G. Tj; Jongbloed, M. R. M.; Willems, T. P.; Pieper, P. G.

    2012-01-01

    Data on long-term complications in adult patients with congenital heart disease (ACHD) and a prosthetic valve are scarce. Moreover, the influence of prosthetic valves on quality of life (QoL) and functional outcome in ACHD patients with prosthetic valves has not been studied. The primary objective

  19. 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

    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

  20. 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

  1. A 3D velocimetry study of the flow through prosthetic heart valves

    Science.gov (United States)

    Ledesma, R.; Zenit, R.; Pulos, G.; Sanchez, E.; Juarez, A.

    2006-11-01

    Blood damage commonly appears in medical valve prothesis. It is a mayor concern for the designers and surgeons. It is well known that this damage and other complications result from the modified fluid dynamics through the replacement valve. To evaluate the performance of prosthetic heart valves, it is necessary to study the flow through them. To conduct this study , we have built a flow channel that emulates cardiac conditions and allows optical access such that a 3D-PIV velocimetry system could be used. The experiments are aimed to reconstruct the downstream structure of the flow through a mechanical and a bio-material tricuspid heart valve prothesis. Preliminary results show that the observed coherent structures can be related with haemolysis and trombosis, illnesses commonly found in valve prothesis recipients. The mean flow, the levels of strain rate and the turbulence intensity generated by the valves can also be directly related to blood damage. In general, bio-material made valves tend to reduce these complications.

  2. Relationships between melanocytes, mechanical properties and extracellular matrix composition in mouse heart valves.

    Science.gov (United States)

    Carneiro, Flavia; Kruithof, Boudewijn Pt; Balani, Kanthesh; Agarwal, Arvind; Gaussin, Vinciane; Kos, Lidia

    2015-01-01

    Heart valves are complex structures composed of organized layers of extracellular matrix, and interstitial and overlying endothelial cells. In this article, we present the specific localization of a population of melanocytes within the murine heart valves at ages important for their post-natal development. In all stages analyzed in our study, melanocytes were found in high numbers populating the atrial aspect of the tricuspid and mitral leaflets. The pulmonary valve did not present melanocytes. To characterize a putative role for the valve melanocytes, the dynamic nanomechanical properties of tricuspid leaftets containing large numbers or no melanocytes were measured. The stiffness coefficient of hyperpigmented leaflets was higher (11.5 GPa) than the ones from wild-type (7.5 GPa) and hypopigmented (5.5 GPa) leaflets. These results suggest that melanocytes may contribute to the mechanical properties of the heart valves. The arrangement of extracellular matrix molecules such as Collagen I and Versican B is responsible for the mechanical characteristics of the leaflets. Melanocytes were found to reside primarily in areas of Versican B expression. The patterns of expression of Collagen I and Versican B were not, however, disrupted in hyper or hypopigmented leaflets. Melanocytes may affect other extracellular matrix molecules to alter the valves' microenvironment.

  3. Postoperative anticoagulation in patients with mechanical heart valves following surgical treatment of subdural hematomas.

    Science.gov (United States)

    Amin, Anubhav G; Ng, Julie; Hsu, Wesley; Pradilla, Gustavo; Raza, Shaan; Quinones-Hinojosa, Alfredo; Lim, Michael

    2013-08-01

    Thromboembolic events and anticoagulation-associated bleeding events represent frequent complications following cardiac mechanical valve replacement. Management guidelines regarding the timing for resuming anticoagulation therapy following a surgically treated subdural hematoma (SDH) in patients with mechanical valves remains to be determined. To determine optimal anticoagulation management in patients with mechanical heart valves following treatment of SDH. Outcomes were retrospectively reviewed for 12 patients on anticoagulation therapy for thromboembolic prophylaxis for mechanical cardiac valves who underwent surgical intervention for a SDH at the Johns Hopkins Hospital between 1995 and 2010. The mean age at admission was 71 years. All patients had St. Jude's mechanical heart valves and were receiving anticoagulation therapy. All patients had their anticoagulation reversed with vitamin K and fresh frozen plasma and underwent surgical evacuation. Anticoagulation was withheld for a mean of 14 days upon admission and a mean of 9 days postoperatively. The average length of stay was 19 days. No deaths or thromboembolic events occurred during the hospitalization. Average follow-up time was 50 months, during which two patients had a recurrent SDH. No other associated morbidities occurred during follow-up. Interruptions in anticoagulation therapy for up to 3 weeks pose minimal thromboembolic risk in patients with mechanical heart valves. Close follow-up after discharge is highly recommended, as recurrent hemorrhages can occur several weeks after the resumption of anticoagulation.

  4. Guided Tissue Regeneration in Heart Valve Replacement: From Preclinical Research to First-in-Human Trials

    Directory of Open Access Journals (Sweden)

    L. Iop

    2015-01-01

    Full Text Available Heart valve tissue-guided regeneration aims to offer a functional and viable alternative to current prosthetic replacements. Not requiring previous cell seeding and conditioning in bioreactors, such exceptional tissue engineering approach is a very fascinating translational regenerative strategy. After in vivo implantation, decellularized heart valve scaffolds drive their same repopulation by recipient’s cells for a prospective autologous-like tissue reconstruction, remodeling, and adaptation to the somatic growth of the patient. With such a viability, tissue-guided regenerated conduits can be delivered as off-the-shelf biodevices and possess all the potentialities for a long-lasting resolution of the dramatic inconvenience of heart valve diseases, both in children and in the elderly. A review on preclinical and clinical investigations of this therapeutic concept is provided with evaluation of the issues still to be well deliberated for an effective and safe in-human application.

  5. Guided tissue regeneration in heart valve replacement: from preclinical research to first-in-human trials.

    Science.gov (United States)

    Iop, L; Gerosa, G

    2015-01-01

    Heart valve tissue-guided regeneration aims to offer a functional and viable alternative to current prosthetic replacements. Not requiring previous cell seeding and conditioning in bioreactors, such exceptional tissue engineering approach is a very fascinating translational regenerative strategy. After in vivo implantation, decellularized heart valve scaffolds drive their same repopulation by recipient's cells for a prospective autologous-like tissue reconstruction, remodeling, and adaptation to the somatic growth of the patient. With such a viability, tissue-guided regenerated conduits can be delivered as off-the-shelf biodevices and possess all the potentialities for a long-lasting resolution of the dramatic inconvenience of heart valve diseases, both in children and in the elderly. A review on preclinical and clinical investigations of this therapeutic concept is provided with evaluation of the issues still to be well deliberated for an effective and safe in-human application.

  6. [INR Self-management after mechanical heart valve replacement: ESCAT (Early Self-Controlled Anticoagulation Trial)].

    Science.gov (United States)

    Körtke, H; Minami, K; Breymann, T; Seifert, D; Baraktaris, A; Wagner, O; Kleikamp, G; El-Banayosy, A; Mirow, N; Körfer, R

    2001-12-01

    Severe thromboembolic and hemorrhagic complications following mechanical heart valve replacement essentially occur due to intense oral anticoagulation and fluctuating individual INR values around the target range. INR self-management can help to minimize these fluctuations. Beginning this therapeutic control immediately after mechanical heart valve replacement further reduces anticoagulant-induced complications. Included in the study were 1200 patients. The quality of oral anticoagulation also improved through INR self-management. Over an observation period of two years, nearly 80 % of INR values recorded by the patients themselves were within the target therapeutic range of 2.5-4.5. This corresponds to a high significance of p grammar with or without university). Of patients trained in INR self-management following mechanical heart valve replacement, 91.7 % maintained their competence in this technique throughout the entire follow-up period. Only 8.3 % of those trained immediately after surgery were unable to continue with INR self-management.

  7. Recommendations for the anticoagulation of pregnant patients with mechanical heart valves.

    Science.gov (United States)

    Schapkaitz, Elise; Jacobson, Barry Frank; Manga, Pravin; Chitsike, Rufaro Saeed; Benade, Estee; Jackson, S; Haas, Sylvia; Buller, Harry R

    2015-09-14

    The management of pregnant patients with mechanical heart valves remains challenging because there are no large randomised studies to provide guidelines for effective anticoagulant therapy. Both vitamin K antagonists and heparins may be associated with maternal and foetal adverse events. The Southern African Society of Thrombosis and Haemostasis reviewed available literature and comprehensive evidence-based guidelines for the anticoagulation of pregnant patients with mechanical heart valves. A draft document was produced and revised by consensus agreement. The guidelines were adjudicated by independent international experts to avoid local bias. We present concise, practical guidelines for the clinical management of pregnant patients with mechanical heart valves. Recommendations reflect current best practice which will hopefully lead to improved anticoagulation practice in this select group of high risk patients.

  8. Microstructured Nickel-Titanium Thin Film Leaflets for Hybrid Tissue Engineered Heart Valves Fabricated by Magnetron Sputter Deposition.

    Science.gov (United States)

    Loger, K; Engel, A; Haupt, J; Lima de Miranda, R; Lutter, G; Quandt, E

    2016-03-01

    Heart valves are constantly exposed to high dynamic loading and are prone to degeneration. Therefore, it is a challenge to develop a durable heart valve substitute. A promising approach in heart valve engineering is the development of hybrid scaffolds which are composed of a mechanically strong inorganic mesh enclosed by valvular tissue. In order to engineer an efficient, durable and very thin heart valve for transcatheter implantations, we developed a fabrication process for microstructured heart valve leaflets made from a nickel-titanium (NiTi) thin film shape memory alloy. To examine the capability of microstructured NiTi thin film as a matrix scaffold for tissue engineered hybrid heart valves, leaflets were successfully seeded with smooth muscle cells (SMCs). In vitro pulsatile hydrodynamic testing of the NiTi thin film valve leaflets demonstrated that the SMC layer significantly improved the diastolic sufficiency of the microstructured leaflets, without affecting the systolic efficiency. Compared to an established porcine reference valve model, magnetron sputtered NiTi thin film material demonstrated its suitability for hybrid tissue engineered heart valves.

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

    Science.gov (United States)

    Moutaouekkil, El Mehdi; Najib, Abdelmalek; Ajaja, Rida; Arji, Moha; Slaoui, Anas

    2015-01-01

    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. 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. 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. 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.

  11. Towards Optimization of a Novel Trileaflet Polymeric Prosthetic Heart Valve Via Device Thrombogenicity Emulation (DTE)

    Science.gov (United States)

    Claiborne, Thomas E.; Xenos, Michalis; Sheriff, Jawaad; Chiu, Wei-Che; Soares, Joao; Alemu, Yared; Gupta, Shikha; Judex, Stefan; Slepian, Marvin J.; Bluestein, Danny

    2013-01-01

    Aortic stenosis the is most prevalent and life threatening form of valvular heart disease. It is primarily treated via open-heart surgical valve replacement with either a tissue or mechanical prosthetic heart valve (PHV), each prone to degradation and thrombosis, respectively. Polymeric PHVs may be optimized to eliminate these complications, and they may be more suitable for the new transcatheter aortic valve replacement (TAVR) procedure and in devices like the Total Artificial Heart. However, the development of polymer PHVs has been hampered by persistent in vivo calcification, degradation, and thrombosis. To address these issues, we have developed a novel surgically implantable polymer PHV comprised of a new thermoset polyolefin called xSIBS, in which key parameters were optimized for superior functionality via our Device Thrombogenicity Emulation (DTE) methodology. In this parametric study, we compared our homogeneous optimized polymer PHV to a prior composite polymer PHV and to a benchmark tissue valve. Our results show significantly improved hemodynamics and reduced thrombogenicity in the optimized polymer PHV compared to the other valves. These results indicate that our new design may not require anticoagulants and may be more durable than its predecessor, and validates the improvement, towards optimization, of this novel polymeric PHV design. PMID:23644615

  12. TCT-670 Optimal Transcatheter Heart Valve Sizing in Aortic Valve in Valve Implantation: Insights from the Valve in Valve International Data (VIVID) Registry

    DEFF Research Database (Denmark)

    Alnasser, Sami; Cheema, Asim N; Horlick, Eric

    2016-01-01

    )/true ID x 100. Results: A total of 595 patients (359 for standard size and 236 for oversized group) were included in the analysis. Baseline clinical, hemodynamic and surgical valve parameters were similar in these two groups. Both groups used similar THV devices in each matched comparison. The oversized.......1±8.1mmHg vs. 17.4±8.5mmHg, p=0.002) in comparison to the standard cohort. The oversized group however, had a higher rate of moderate to severe AI (6.9% vs. 2.7%, p=0.001) and second THV requirement (5.5%vs. 2.2%, p=0.04). THV mal-positioning, coronary obstruction and postoperative pacemaker requirement...

  13. Does the Use of a Decision Aid Improve Decision Making in Prosthetic Heart Valve Selection? A Multicenter Randomized Trial

    NARCIS (Netherlands)

    Korteland, Nelleke M.; Ahmed, Yunus; Koolbergen, David R.; Brouwer, Marjan; de Heer, Frederiek; Kluin, Jolanda; Bruggemans, Eline F.; Klautz, Robert J. M.; Stiggelbout, Anne M.; Bucx, Jeroen J. J.; Roos-Hesselink, Jolien W.; Polak, Peter; Markou, Thanasie; van den Broek, Inge; Ligthart, Rene; Bogers, Ad J. J. C.; Takkenberg, Johanna J. M.

    2017-01-01

    A Dutch online patient decision aid to support prosthetic heart valve selection was recently developed. A multicenter randomized controlled trial was conducted to assess whether use of the patient decision aid results in optimization of shared decision making in prosthetic heart valve selection. In

  14. Favorable Effects of the Detergent and Enzyme Extraction Method for Preparing Decellularized Bovine Pericardium Scaffold for Tissue Engineered Heart Valves

    NARCIS (Netherlands)

    Yang, Min; Chen, Chang-Zhi; Wang, Xue-Ning; Zhu, Ya-Bin; Gu, Y. John

    2009-01-01

    Bovine pericardium has been extensively applied as the biomaterial for artificial heart valves and may potentially be used as a scaffold for tissue-engineered heart valves after decellularization. Although various methods of decellularization are currently available, it is unknown which method is

  15. Maternal complications and pregnancy outcome in women with mechanical prosthetic heart valves treated with enoxaparin.

    Science.gov (United States)

    McLintock, C; McCowan, L M E; North, R A

    2009-11-01

    To determine maternal and fetal outcomes in women with mechanical heart valves managed with therapeutic dose enoxaparin during pregnancy. Retrospective audit. Hospital-based high-risk antenatal clinics. Pregnant women with mechanical heart valves attending high-risk antenatal clinics, treated with enoxaparin (1 mg/kg twice daily) during pregnancy. Women with mechanical heart valves treated with enoxaparin at any stage during pregnancy (1997-2008) identified using a database of women with mechanical heart valves attending the high-risk clinics and a prospective database of women prescribed enoxaparin for any indication during pregnancy. Maternal outcomes included thromboembolic and haemorrhagic complications. Pregnancy and fetal outcomes included miscarriage, stillbirth, baby death and live birth, small-for-gestational-age infants, warfarin embryopathy and warfarin-related fetal loss. Thirty-one women underwent 47 pregnancies. In 34 pregnancies (72.3%), anticoagulation was with predominantly enoxaparin and 13 (27.7%) pregnancies women received mainly warfarin, with enoxaparin given in the first trimester and/or peri-delivery. Seven (14.9%) thrombotic complications occurred, of which five (10.6%) were associated with enoxaparin treatment. Non-compliance or sub-therapeutic anti-Xa levels contributed in each case. Antenatal and postpartum haemorrhagic complications occurred in eight (17%) and 15 (32%) pregnancies respectively. Of 35 pregnancies continuing after 20 weeks' gestation, 96% (22/23) of women taking predominantly enoxaparin had a surviving infant compared with 75% (9/12) in women taking primarily warfarin. Four perinatal deaths occurred, three attributable to warfarin. Compliance with therapeutic dose enoxaparin and aspirin during pregnancy in women with mechanical heart valves is associated with a low risk of valve thrombosis and good fetal outcomes, but close monitoring is essential.

  16. A method for real-time in vitro observation of cavitation on prosthetic heart valves.

    Science.gov (United States)

    Zapanta, C M; Liszka, E G; Lamson, T C; Stinebring, D R; Deutsch, S; Geselowitz, D B; Tarbell, J M

    1994-11-01

    A method for real-time in vitro observation of cavitation on a prosthetic heart valve has been developed. Cavitation of four blood analog fluids (distilled water, aqueous glycerin, aqueous polyacrylamide, and aqueous xanthan gum) has been documented for a Medtronic/Hall prosthetic heart valve. This method employed a Penn State Electrical Ventricular Assist Device in a mock circulatory loop that was operated in a partial filling mode associated with reduced atrial filling pressure. The observations were made on a valve that was located in the mitral position, with the cavitation occurring on the inlet side after valve closure on every cycle. Stroboscopic videography was used to document the cavity life cycle. Bubble cavitation was observed on the valve occluder face. Vortex cavitation was observed at two locations in the vicinity of the valve occluder and housing. For each fluid, cavity growth and collapse occurred in less than one millisecond, which provides strong evidence that the cavitation is vaporous rather than gaseous. The cavity duration time was found to decrease with increasing atrial pressure at constant aortic pressure and beat rate. The area of cavitation was found to decrease with increasing delay time at a constant aortic pressure, atrial pressure, and beat rate. Cavitation was found to occur in each of the fluids, with the most cavitation seen in the Newtonian fluids (distilled water and aqueous glycerin).

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

    Science.gov (United States)

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

    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 unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models) exposed to a steady flow regime, on four distinct sections, three downstream and one upstream. Methods To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. ) and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements. Results It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found. Conclusions Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM) is superior to the 21 AJ - 501 model (Master Series). Based on the results, future studies can choose to focus on specific regions of the these valves. PMID:24598950

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

    Directory of Open Access Journals (Sweden)

    Ovandir Bazan

    2013-12-01

    Full Text Available 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 unidimensional velocity profiles at the central plane of two bi-leaflet aortic prosthesis from St. Jude (AGN 21 - 751 and 21 AJ - 501 models exposed to a steady flow regime, on four distinct sections, three downstream and one upstream. METHODS: To provide similar conditions for the flow through each prosthesis by a steady flow workbench (water, flow rate of 17L/min. and, for the same sections and sweeps, to obtain the velocity profiles of each heart valve by unidimensional measurements. RESULTS: It was found that higher velocities correspond to the prosthesis with smaller inner diameter and instabilities of flow are larger as the section of interest is closer to the valve. Regions of recirculation, stagnation of flow, low pressure, and flow peak velocities were also found. CONCLUSIONS: Considering the hydrodynamic aspect and for every section measured, it could be concluded that the prosthesis model AGN 21 - 751 (RegentTM is superior to the 21 AJ - 501 model (Master Series. Based on the results, future studies can choose to focus on specific regions of the these valves.

  19. The optimal method for recording prosthetic heart valve sounds in clinical situations.

    Science.gov (United States)

    Bito, Yasuyuki; Soeta, Yoshiharu; Nakagawa, Seiji; Shibata, Toshihiko; Suehiro, Shigefumi

    2005-12-01

    Valve sounds are thought to be useful in evaluating the functioning of prosthetic heart valves. In previous reports, two recording instruments have mainly been used, a condenser microphone (instrument A) and an accelerometer (instrument B), respectively. This study aimed to investigate the applicability of these conventional devices in recording mechanical heart valve sounds in daily clinical situations. In addition, two other instruments, namely, a stethoscope including a small microphone in its tube (instrument C) and an electrostethoscope (instrument D), were proposed and examined. Mechanical valve sounds were recorded from postoperative patients using each-device and the signal to noise ratio (SNR) of each was calculated. Frequency characteristics of the two newly proposed instruments were also investigated by recording a sweep signal in an anechoic chamber. The SNR values of the new instruments were significantly superior to those of conventional ones (A, sound signals were not defined from noises; B, 0.97 +/- 0.59 dB; C, 11.5 +/- 4.7 dB; and D, 9.4 +/- 3.5 dB, respectively ptwo newly proposed instruments were also shown to be acceptable (under 10 kHz), though resonance frequency peaks were observed. Two newly proposed instruments can record mechanical heart valve sounds more noiselessly and with more ease than previous ones, and their frequency characteristics are acceptable.

  20. The principles and in vivo performance of the Edinburgh pivoted aerofoil-disc prosthetic heart valve.

    Science.gov (United States)

    Macleod, N; Turina, M; Wade, J D; Wheatley, D J

    1977-01-01

    Prototypes of the Edinburgh prosthetic heart valve, known from previous experiments in vitro to promote exceptionally smooth and undisturbed forward flow, have been shown here in canine experiments to possess hemodynamic characteristics not inferior to those of the Bjork-Shiley valve (a present standard of excellence). In addition, we report a low incidence of valve thrombus deposition among calves in which this prototype valve, fabricated from the conventional materials, Delrin and stainless steel, has been implanted in the tricuspid site for up to 100 days without use of anticoagulants. This suggests that the design of the valve is such as to render it of low thrombogenicity. The new valve is designed for fabrication throughout in vitreous or pyro-coated carbon, materials of very high inherent athrombogenicity. It appears from the results discussed here that the developed form of the prosthesis, composed wholly of these athrombogenic materials, is likely to have both acceptable hemodynamic characteristics and an exceptionally low tendency to form thrombus. The introduction of such valves promises to be very advantageous and the results given here appear to warrant their development as the next stage of this program.

  1. Biomechanical conditioning of tissue engineered heart valves: Too much of a good thing?

    Science.gov (United States)

    Parvin Nejad, Shouka; Blaser, Mark C; Santerre, J Paul; Caldarone, Christopher A; Simmons, Craig A

    2016-01-15

    Surgical replacement of dysfunctional valves is the primary option for the treatment of valvular disease and congenital defects. Existing mechanical and bioprosthetic replacement valves are far from ideal, requiring concomitant anticoagulation therapy or having limited durability, thus necessitating further surgical intervention. Heart valve tissue engineering (HVTE) is a promising alternative to existing replacement options, with the potential to synthesize mechanically robust tissue capable of growth, repair, and remodeling. The clinical realization of a bioengineered valve relies on the appropriate combination of cells, biomaterials, and/or bioreactor conditioning. Biomechanical conditioning of valves in vitro promotes differentiation of progenitor cells to tissue-synthesizing myofibroblasts and prepares the construct to withstand the complex hemodynamic environment of the native valve. While this is a crucial step in most HVTE strategies, it also may contribute to fibrosis, the primary limitation of engineered valves, through sustained myofibrogenesis. In this review, we examine the progress of HVTE and the role of mechanical conditioning in the synthesis of mechanically robust tissue, and suggest approaches to achieve myofibroblast quiescence and prevent fibrosis. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Effect of a combined anti-thrombotic therapy of thrombosis on prosthetic heart valves.

    Science.gov (United States)

    Wei, Wei; Dong, Taiming; Zheng, Zhichao; Huang, Shuping

    2015-03-01

    To evaluate the curative effects and risks of a medical therapy with combined anti-thrombotic agents for thrombosis on prosthetic heart valves. Twenty-two patients who suffered from thrombosis on prosthetic valves with stable hemodynamics were divided into the inpatient group and the outpatient group. Thrombosis on the valves were demonstrated by transesophageal echocardiographies (TEE). A combined anti-thrombotic therapy with clopidogrel and warfarin were prescribed for all the patients during the whole treatment. Low molecular weight heparin (LMWH) was given twice daily during the first 5 days for the inpatients. The patients accepted regular follow-ups for observation of the functions of prosthetic valves, changes of thrombi, coagulation status and general clinical status. There were 5 men and 17 women. Thirteen patients suffered from thrombosis on the mechanical mitral valves (MVs), five on the mechanical tricuspid valves (TVs), one on the mechanical aortic valve and tricuspid bio-prosthetic valve, one on the mechanical aortic valve, one on the mitral bio-prosthetic valve, and one on the tricuspid bio-prosthetic valve. After an average of 36.4±23.1 days' observation, 16 (73%) patients' valvular function recovered normal without TTE detectable thrombi, 6 (27%) patients' valvular function remained abnormal including three patients without TTE detectable thrombi during follow-ups. No significant differences of thrombi changes and period of thrombi disappearance were observed between the inpatient group and the outpatient group. For patients with mitral thrombosis, sizes of the left atriums (LAs) decreased an average of 4.1 mm after treatment (95% CI, 1.2-6.9 mm). No significant changes of other chambers and left ventricular ejection fractions (LVEF) were observed. For patients with tricuspid thrombosis, LVEF improved an average of 10.5% after treatment (95% CI, 0.1-17.9%). No significant changes of chambers were observed. None experienced major bleedings except

  3. Scleraxis is required for cell lineage differentiation and extracellular matrix remodeling during murine heart valve formation in vivo.

    Science.gov (United States)

    Levay, Agata K; Peacock, Jacqueline D; Lu, Yinhui; Koch, Manuel; Hinton, Robert B; Kadler, Karl E; Lincoln, Joy

    2008-10-24

    Heart valve structures, derived from mesenchyme precursor cells, are composed of differentiated cell types and extracellular matrix arranged to facilitate valve function. Scleraxis (scx) is a transcription factor required for tendon cell differentiation and matrix organization. This study identified high levels of scx expression in remodeling heart valve structures at embryonic day 15.5 through postnatal stages using scx-GFP reporter mice and determined the in vivo function using mice null for scx. Scx(-/-) mice display significantly thickened heart valve structures from embryonic day 17.5, and valves from mutant mice show alterations in valve precursor cell differentiation and matrix organization. This is indicated by decreased expression of the tendon-related collagen type XIV, increased expression of cartilage-associated genes including sox9, as well as persistent expression of mesenchyme cell markers including msx1 and snai1. In addition, ultrastructure analysis reveals disarray of extracellular matrix and collagen fiber organization within the valve leaflet. Thickened valve structures and increased expression of matrix remodeling genes characteristic of human heart valve disease are observed in juvenile scx(-/-) mice. In addition, excessive collagen deposition in annular structures within the atrioventricular junction is observed. Collectively, our studies have identified an in vivo requirement for scx during valvulogenesis and demonstrate its role in cell lineage differentiation and matrix distribution in remodeling valve structures.

  4. Conceptual model for early health technology assessment of current and novel heart valve interventions.

    Science.gov (United States)

    Huygens, Simone A; Rutten-van Mölken, Maureen P M H; Bekkers, Jos A; Bogers, Ad J J C; Bouten, Carlijn V C; Chamuleau, Steven A J; de Jaegere, Peter P T; Kappetein, Arie Pieter; Kluin, Jolanda; van Mieghem, Nicolas M D A; Versteegh, Michel I M; Witsenburg, Maarten; Takkenberg, Johanna J M

    2016-01-01

    The future promises many technological advances in the field of heart valve interventions, like tissue-engineered heart valves (TEHV). Prior to introduction in clinical practice, it is essential to perform early health technology assessment. We aim to develop a conceptual model (CM) that can be used to investigate the performance and costs requirements for TEHV to become cost-effective. After scoping the decision problem, a workgroup developed the draft CM based on clinical guidelines. This model was compared with existing models for cost-effectiveness of heart valve interventions, identified by systematic literature search. Next, it was discussed with a Delphi panel of cardiothoracic surgeons, cardiologists and a biomedical scientist (n=10). The CM starts with the valve implantation. If patients survive the intervention, they can remain alive without complications, die from non-valve-related causes or experience a valve-related event. The events are separated in early and late events. After surviving an event, patients can experience another event or die due to non-valve-related causes. Predictors will include age, gender, NYHA class, left ventricular function and diabetes. Costs and quality adjusted life years are to be attached to health conditions to estimate long-term costs and health outcomes. We developed a CM that will serve as foundation of a decision-analytic model that can estimate the potential cost-effectiveness of TEHV in early development stages. This supports developers in deciding about further development of TEHV and identifies promising interventions that may result in faster take-up in clinical practice by clinicians and reimbursement by payers.

  5. Long-term results of mechanical and biological heart valves in dialysis and non-dialysis patients.

    Science.gov (United States)

    Böning, A; Boedeker, R H; Rosendahl, U P; Niemann, B; Haberer, S; Roth, P; Ennker, J A C

    2011-12-01

    We wanted to answer the question whether biological heart valves are inferior compared to mechanical heart valves in end-stage renal disease (ESRD) patients. Between 01/1996 und 12/2006, 44 of 3293 patients undergoing aortic valve replacement (AVR) in a single institution suffered from dialysis-dependent ESRD and underwent a follow-up investigation after 1.9 years (median). Twelve (28.9 %) of these patients received a biological, 32 (71.1 %) of these patients a mechanical aortic valve prosthesis. To evaluate a possible influence of the valve type (biological/mechanical) on survival, uni- and multivariate logistic regression was used. ESRD patients after AVR had a relatively poor short-term (30-day mortality: 22.7 %) and long-term survival (median survival time: 24.7 months; 95 % CI: 0.2-47.7 months), irrespective of the type of heart valve prosthesis (hazard ratio for mortality depending on heart valve type in dialysis patients: 1.31, P = 0.400). Dialysis-dependent patients were not reoperated due to valve-related reasons. The long-term survival of dialysis-dependent patients after AVR is low (5-year survival: 29.5 %) irrespective of the type of heart valve prosthesis. Therefore, the use of biological AVR is not contraindicated in this group of patients. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Cardiac computed tomography angiography results in diagnostic and therapeutic change in prosthetic heart valve endocarditis

    NARCIS (Netherlands)

    Habets, Jesse; Tanis, Wilco; van Herwerden, Lex A.; van den Brink, Renee B. A.; Mali, Willem P. Th M.; de Mol, Bas A. J. M.; Chamuleau, Steven A. J.; Budde, Ricardo P. J.

    2014-01-01

    Echocardiography may miss prosthetic heart valve (PHV) endocarditis which advocates for novel imaging techniques to improve diagnostic accuracy and patient outcome. The purpose of this study was to determine the complementary diagnostic value of cardiac computed tomography angiography (CTA) to the

  7. Long-term tricuspid valve prosthesis-related complications in patients with congenital heart disease

    NARCIS (Netherlands)

    van Slooten, Ymkje J.; Freling, Hendrik G.; van Melle, Joost P.; Mulder, Barbara J. M.; Jongbloed, Monique R. M.; Ebels, Tjark; Voors, Adriaan A.; Pieper, Petronella G.

    OBJECTIVES: In patients with acquired valvar disease, morbidity and mortality rates after tricuspid valve replacement (TVR) are high. However, in adult patients with congenital heart disease, though data concerning outcome after TVR are scarce, even poorer results are suggested in patients with

  8. Real time, non-invasive assessment of leaflet deformation in heart valve tissue engineering.

    Science.gov (United States)

    Kortsmit, J; Driessen, N J B; Rutten, M C M; Baaijens, F P T

    2009-03-01

    In heart valve tissue engineering, most bioreactors try to mimic physiological flow and operate with a preset transvalvular pressure applied to the tissue. The induced deformations are unknown and can vary during culturing as a consequence of changing mechanical properties of the engineered construct. Real-time measurement and control of local tissue strains are desired to systematically study the effects of mechanical loading on tissue development and, consequently, to design an optimal conditioning protocol. In this study, a method is presented to assess local tissue strains in heart valve leaflets during culturing. We hypothesize that local tissue strains can be determined from volumetric deformation. Volumetric deformation is defined as the amount of fluid displaced by the deformed heart valve leaflets in a stented configuration, and is measured, non-invasively, using a flow sensor. A numerical model is employed to relate volumetric deformation to local tissue strains in various regions of the leaflets (e.g. belly and commissures). The flow-based deformation measurement method was validated and its functionality was demonstrated in a tissue engineering experiment. Tri-leaflet, stented heart valves were cultured in vitro and during mechanical conditioning, realistic values for volumetric and local deformation were obtained.

  9. Prosthetic heart valve thrombosis, anticoagulation and pregnancy: a case report and review of literature.

    NARCIS (Netherlands)

    Kuilenburg, J.T. van; Verheugt, F.W.A.; Dijk, A.P.J. van

    2007-01-01

    In pregnant patients with a prosthetic heart valve (PHV), anticoagulation with warfarin is associated with embryopathy, foetal loss early in pregnancy and maternal bleeding complications in the delivery period. The optimal anticoagulation strategy in the pre-pregnancy period and during pregnancy

  10. Anti-coagulation during pregnancy in women with mechanical heart valves: a prospective study.

    Science.gov (United States)

    Khamoushi, Amir Jamshid; Kashfi, Fahimeh; Hosseini, Saeid; Alizadeh Ghavidel, Ali Reza; Samiei, Niloufar; Haddadzadeh, Mehdi

    2011-04-01

    Pregnancy is associated with a hypercoagulable state, therefore the optimal anticoagulants for potential use in pregnant women with prosthetic heart valves are controversial. The aim of this study is to investigate the effect of anticoagulants on pregnancy outcomes and their potential risks in pregnant women with mechanical heart valves. In this prospective cohort study, we followed 44 women with 49 pregnancies who had mechanical heart valves from September 2002 to September 2007. A total of 38 patients took warfarin throughout their pregnancies (group A). In 11 patients, warfarin was changed to heparin during the first trimester and then again to warfarin during 12thto 36thweeks of gestational age (group B). All women took warfarin from 36thweeks of gestational age until delivery. In group A, there were 22 live births (57.9%), 15 abortions (39.5%) and 1 maternal death (2.6%). In group B, there were seven live births (63.6%), three spontaneous abortions (27.3%) and one intra-uterine fetal death (9.1%). There was no significant difference in live birth rate between the two groups (p=0.24). Thirty-three pregnancies (86.8%) in group A and five pregnancies (45.4%) in group B had no maternal complications (p=0.004). The difference in pregnancy complications between both groups was significant (pmechanical heart valves remain on a warfarin regimen. The risk of embryopathy does not necessarily increase.

  11. Recommendations for the anticoagulation of pregnant patients with mechanical heart valves

    NARCIS (Netherlands)

    Schapkaitz, Elise; Jacobson, Barry Frank; Manga, Pravin; Chitsike, Rufaro Saeed; Benade, Estee; Haas, Sylvia; Buller, Harry R.

    2015-01-01

    The management of pregnant patients with mechanical heart valves remains challenging because there are no large randomised studies to provide guidelines for effective anticoagulant therapy. Both vitamin K antagonists and heparins may be associated with maternal and foetal adverse events. The

  12. Outcome and performance of bioprosthetic pulmonary valve replacement in patients with congenital heart disease.

    Science.gov (United States)

    Nomoto, Rio; Sleeper, Lynn A; Borisuk, Michele J; Bergerson, Lisa; Pigula, Frank A; Emani, Sitaram; Fynn-Thompson, Francis; Mayer, John E; Del Nido, Pedro J; Baird, Christopher W

    2016-11-01

    The goal of this single-center series was to assess differences in reintervention by the type of valve used for surgical bioprosthetic pulmonary valve replacement and to identify independent predictors of reintervention. Data were retrospectively collected for 611 patients undergoing pulmonary valve replacement from 1996 to 2014. Kaplan-Meier estimation and Cox proportional hazards regression methodologies were used. The median age of patients was 17.8 years (interquartile range, 11.9-27.3). The diagnosis was tetralogy of Fallot in 69% of patients. The median follow-up was 3.0 years (interquartile range, 1.1-5.3). Valve types included Sorin Mitroflow (Milan, Italy), 316 (50%; median age 16.5 years); Carpentier-Edwards (Irvine, Calif) Magna/MagnaEase, 223 (35%; median age, 19.3 years); and Carpentier-Edwards Perimount, 72 (11%; median age, 21.9 years). Reintervention occurred in 6.7% of patients (41/633) and was higher in children than adults (hazard ratio, 4.8). Age-adjusted 5-year reintervention rates were Sorin Mitroflow, 13.4%; Carpentier-Edwards Magna/MagnaEase, 2.1%; and Carpentier-Edwards Perimount, 0%. Reintervention was not associated with gender, valve insertion method, or concurrent procedures. The only independent risk factor for reintervention after controlling for age was valve type (P types (hazard ratios both >7, each P type did not depend on age (interaction P = .61). Bioprosthetic pulmonary valve replacement in patients with congenital heart disease has excellent short-term outcomes, but children have an approximately 5-fold greater risk of reintervention than adults. Independently of age, reintervention rates vary by valve type. These differences may be important in valve selection and follow-up. Copyright © 2016. Published by Elsevier Inc.

  13. Adherence of Staphylococcus aureus to Dyneema Purity® Patches and to Clinically Used Cardiovascular Prostheses.

    Science.gov (United States)

    Basir, Amir; Gründeman, Paul; Moll, Frans; van Herwaarden, Joost; Pasterkamp, Gerard; Nijland, Reindert

    2016-01-01

    Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for prostheses is Dyneema Purity®, made of ultra-high-molecular-weight polyethylene. Dyneema Purity® fibers are very thin, flexible, resistant to fatigue and abrasion, and have high strength. S. aureus adherence to Dyneema Purity® was tested and compared with currently used cardiovascular prostheses. We compared adhesion of S. aureus to Dyneema Purity® (1 membrane-based and 1 yarn-composed patch) with 5 clinically used yarn-composed polyester and membrane-based expanded polytetrafluoroethylene patches. Patches were contaminated with S. aureus bacteria and bacterial adherence was quantified. S. aureus adherence was also visualized in flow conditions. Overall, bacterial adherence was higher on yarn-composed prosthesis materials, with a rough surface, than on the membrane-based materials, with a smooth surface. Adherence to Dyneema Purity® materials was non-inferior to the currently used materials. Therefore, patches of Dyneema Purity® might be attractive for use in cardiovascular applications such as catheter-based heart valves and endovascular prostheses by their good mechanical properties combined with their noninferiority regarding bacterial adhesion.

  14. Adherence of Staphylococcus aureus to Dyneema Purity® Patches and to Clinically Used Cardiovascular Prostheses.

    Directory of Open Access Journals (Sweden)

    Amir Basir

    Full Text Available Various materials that are used for vascular and heart valve prostheses carry drawbacks: some require anticoagulant drugs or have moderate durability; others are not suitable for endovascular treatment. These prostheses are associated with bacterial infections. A material potentially suitable for prostheses is Dyneema Purity®, made of ultra-high-molecular-weight polyethylene. Dyneema Purity® fibers are very thin, flexible, resistant to fatigue and abrasion, and have high strength. S. aureus adherence to Dyneema Purity® was tested and compared with currently used cardiovascular prostheses. We compared adhesion of S. aureus to Dyneema Purity® (1 membrane-based and 1 yarn-composed patch with 5 clinically used yarn-composed polyester and membrane-based expanded polytetrafluoroethylene patches. Patches were contaminated with S. aureus bacteria and bacterial adherence was quantified. S. aureus adherence was also visualized in flow conditions. Overall, bacterial adherence was higher on yarn-composed prosthesis materials, with a rough surface, than on the membrane-based materials, with a smooth surface. Adherence to Dyneema Purity® materials was non-inferior to the currently used materials. Therefore, patches of Dyneema Purity® might be attractive for use in cardiovascular applications such as catheter-based heart valves and endovascular prostheses by their good mechanical properties combined with their noninferiority regarding bacterial adhesion.

  15. Tumors and tumor-like lesions of the heart valves

    Directory of Open Access Journals (Sweden)

    Jacob Lavee

    2009-12-01

    Full Text Available Valvular tumors and tumor-like lesions may have similar morphological and clinical characteristics, and may place the patients at a high risk of stroke in different ways. From January 2004 to June 2008, 11 patients underwent surgery for a suspected valvular tumor. Valvular tumor and tumor-like lesions accounted for 0.32% of adult cardiac operations. Five (45.5% valvular lesions were papillary fibroelastomas, one (9.1% was myxoma, 2 (18.2% were organized thrombi, and 3 (27.3% were calcification lesions. There was a total of 5 (45.5% atrioventricular valve lesions, 4 arising from the atrial side of the leaflets, and one from the ventricular side. All 5 (45.5% semilunar valvular lesions were from the aortic valve. One (9.1% lesion originated from the chorda tendinea of the mitral valve. All leaflet lesions were resected by a simple shave technique, and all the patients recovered favorably. Valvular tumor and tumor-like lesions are rare. Pre-operative differential diagnoses among these valvular lesions pose important clinical implications for appropriate treatment for the underlying diseases. Prompt therapeutic measures in view of the underlying diseases of the valvular lesions are essential to prevent potential embolic events.

  16. Prevalence and Prediction of Obstructive Coronary Artery Disease in Patients Undergoing Primary Heart Valve Surgery.

    Science.gov (United States)

    Cazelli, José Guilherme; Camargo, Gabriel Cordeiro; Kruczan, Dany David; Weksler, Clara; Felipe, Alexandre Rouge; Gottlieb, Ilan

    2017-10-01

    The prevalence of coronary artery disease (CAD) in valvular patients is similar to that of the general population, with the usual association with traditional risk factors. Nevertheless, the search for obstructive CAD is more aggressive in the preoperative period of patients with valvular heart disease, resulting in the indication of invasive coronary angiography (ICA) to almost all adult patients, because it is believed that coronary artery bypass surgery should be associated with valve replacement. To evaluate the prevalence of obstructive CAD and factors associated with it in adult candidates for primary heart valve surgery between 2001 and 2014 at the National Institute of Cardiology (INC) and, thus, derive and validate a predictive obstructive CAD score. Cross-sectional study evaluating 2898 patients with indication for heart surgery of any etiology. Of those, 712 patients, who had valvular heart disease and underwent ICA in the 12 months prior to surgery, were included. The P value arterial hypertension, diabetes mellitus, dyslipidemia, smoking, and male gender. The model showed excellent correlation and calibration (R² = 0.98), as well as excellent accuracy (ROC of 0.848; 95%CI: 0.817-0.879) and validation (ROC of 0.877; 95%CI: 0.830 - 0.923) in different valve populations. Obstructive CAD can be estimated from clinical data of adult candidates for valve repair surgery, using a simple, accurate and validated score, easy to apply in clinical practice, which may contribute to changes in the preoperative strategy of acquired heart valve surgery in patients with a lower probability of obstructive disease.

  17. Experimental study on the Reynolds and viscous shear stress of bileaflet mechanical heart valves in a pneumatic ventricular assist device.

    Science.gov (United States)

    Lee, Hwansung; Tatsumi, Eisuke; Taenaka, Yoshiyuki

    2009-01-01

    Our group is currently developing a pneumatic ventricular assist device (PVAD). In general, the major causes of hemolysis in a pulsatile VAD are cavitation, and Reynolds shear stress (RSS) in the mechanical heart valve (MHV). In a previous study, we investigated MHV cavitation. To select the optimal bileaflet valve for our PVAD, in the current study, we investigated RSS and viscous shear stress (VSS) downstream of three different types of commercial bileaflet valves by means of 2D particle image velocimetry (PIV). To carry out flow visualization inside the blood pump and near the valve, we designed a model pump with the same configuration as that of our PVAD. Three types of bileaflet valves (i.e., the ATS valve, the St. Jude valve, and the Sorin Bicarbon valve) were mounted at the aortic position of the model pump, and flow was visualized according to the PIV method. The maximum flow velocity and RSS of the Sorin Bicarbon valve were lower than those of the other two bileaflet valves. The maximum VSS was only 1% of the maximum RSS. Thus, the effect of VSS on blood cell trauma was neglected. The Sorin Bicarbon valve exhibited relatively low levels of RSS, and was therefore considered to be the best valve for our PVAD among the three valves tested.

  18. Computational Modeling of Blood Flow and Valve Dynamics in Hearts with Hypertrophic Cardiomyopathy

    Science.gov (United States)

    Zheng, Xudong; Mittal, Rajat; Abraham, Theodore; Pinheiro, Aurelio

    2010-11-01

    Hypertrophic Cardiomyopathy (HCM) is a cardiovascular disease manifested by the thickening of the ventricular wall and often leads to a partial obstruction to the blood flow out of the left ventricle. HCM is recognized as one of the most common causes of sudden cardiac death in athletes. In a heart with HCM, the hypertrophy usually narrows the blood flow pathway to the aorta and produces a low pressure zone between the mitral valve and the hypertrophy during systole. This low pressure can suck the mitral valve leaflet back and completely block the blood flow into the aorta. In the current study, a sharp interface immersed boundary method flow solver is employed to study the hemodynamics and valve dynamics inside a heart with HCM. The three-dimensional motion and configuration of the left ventricle including mitral valve leaflets and aortic valves are reconstructed based on echo-cardio data sets. The mechanisms of aortic obstruction associated with HCM are investigated. The long term objective of this study is to develop a computational tool to aid in the assessment and surgical management of HCM.

  19. Fabrication of biomatrix/polymer hybrid scaffold for heart valve tissue engineering in vitro.

    Science.gov (United States)

    Hong, Hao; Dong, Guo Nian; Shi, Wei Jia; Chen, Si; Guo, Chao; Hu, Ping

    2008-01-01

    Decellularized extracellular matrix has been suggested as a scaffold for heart valve tissue engineering or direct implantation. However, cell removal impairs the physical properties of the valve leaflet structure and the biomechanical properties of the valve leaflet. Matrix/polymer hybrid scaffold with improved biomechanical characteristics may be advantageous. Mesenchymal stem cells were obtained from rats. Porcine aortic valve leaflets were decellularized enzymatically and coated with biodegradable poly-4-hydroxybutyrate using an electrospinning technique, reseeded and cultured over a time period of 14 days. The morphologic, biochemical, and biomechanical characteristics of hybrid scaffolds were tested. Morphologic and biochemical assays indicated that mesenchymal stem cells survive and proliferate on hybrid scaffolds, and control decellularized scaffolds revealed comparable amounts of cell mass, 4-hydroxyproline and collagen after cultured in vitro for 14 days. Mechanical testing indicated hybrid scaffolds had superior tensile strength and elastic modulus. Altogether this study demonstrates the feasibility and improved biomechanical characteristics of a novel hybrid heart valve leaflet scaffold for an application in tissue engineering.

  20. Hemodynamic Performance and Thrombogenic Properties of a Superhydrophobic Bileaflet Mechanical Heart Valve

    Science.gov (United States)

    Bark, David L.; Vahabi, Hamed; Bui, Hieu; Movafaghi, Sanli; Moore, Brandon; Kota, Arun K.; Popat, Ketul; Dasi, Lakshmi P.

    2016-01-01

    In this study, we explore how blood-material interactions and hemodynamics are impacted by rendering a clinical quality 25 mm St. Jude Medical Bileaflet mechanical heart valve (BMHV) superhydrophobic (SH) with the aim of reducing thrombo-embolic complications associated with BMHVs. Basic cell adhesion is evaluated to assess blood-material interactions, while hemodynamic performance is analyzed with and without the SH coating. Results show that a SH coating with a receding contact angle (CA) of 160º strikingly eliminates platelet and leukocyte adhesion to the surface. Alternatively, many platelets attach to and activate on pyrolytic carbon (receding CA=47), the base material for BMHVs. We further show that the performance index increases by 2.5% for coated valve relative to an uncoated valve, with a maximum possible improved performance of 5%. Both valves exhibit instantaneous shear stress below 10 N/m2 and Reynolds Shear Stress below 100 N/m2. Therefore, a SH BMHV has the potential to relax the requirement for antiplatelet and anticoagulant drug regimens typically required for patients receiving MHVs by minimizing blood-material interactions, while having a minimal impact on hemodynamics. We show for the first time that SH-coated surfaces may be a promising direction to minimize thrombotic complications in complex devices such as heart valves. PMID:27098219

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

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    Carlo de Oliveira Martins

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

  2. Measurement of pulsatile turbulent flow downstream of polyurethane heart valve prosthesis using particle image velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.K.; Sung, J.Y. [Graduate School, Seoul National University, Seoul (Korea); Chang, J.K.; Min, B.G.; Yoo, J.Y. [Seoul National University, Seoul (Korea)

    1998-11-01

    In-vitro flow characteristics downstream of a polyurethane artificial heart valve under a pulsatile flow condition were investigated using Particle Image Velocimetry (PIV). With a triggering system and a time-delay circuit the velocity field downstream of the valve was evaluated in conjunction with the opening behavior of a flexible valve leaflet during a cardiac cycle.. Reynolds shear stress distribution was calculated from the velocity fields at a peak systolic phase. Direct measurements of the wall shear stress by hot-film anemometry (HFA) were compared with the PIV data. The possibilities of vascular complications, such as the thrombus formation and red blood cell damage, could be estimated from the overall view of the instantaneous velocity and stress fields obtained. A correlation between the flow pattern downstream of the valve and the corresponding opening posture of the polyurethane valve membrane gives useful data necessary for the improved design of the frame structure and leaflet geometry of the valve. (author). 11 refs., 8 figs., 5 tabs.

  3. Design improvement of the jellyfish valve for long-term use in artificial hearts.

    Science.gov (United States)

    Iwasaki, K; Umezu, M; Imachi, K; Iijima, K; Fujimoto, T

    2001-07-01

    In a previous communication, we reported a leaflet fracture in a Jellyfish valve that was incorporated into a blood pump, after a 312-day animal implant duration. Subsequent finite element analysis revealed that the fracture location was consistent with an area of maximum strain concentration. Therefore, the aim of this study was to improve the durability in the light of these findings. Based on the engineering analysis results, a new valve seat having a concentric ring of 0.5-mm width, located at a radius of 7.0 mm, was designed and fabricated. Accelerated fatigue tests, conducted under the conditions recommended by ISO 5840, demonstrated that the durability of this new prototype was extended by a factor of 10, as compared to the original valve. Moreover, further finite element analysis indicated that the maximum equivalent elastic strain of the proposed new valve was reduced by 52.3% as compared to the original valve. Accordingly, it has been confirmed that the modified Jellyfish valve is suitable for use in long-term artificial hearts.

  4. 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.

  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. Exercise-based cardiac rehabilitation for adults after heart valve surgery

    DEFF Research Database (Denmark)

    Sibilitz, Kirstine Lærum; Berg, Selina Kikkenborg; Tang, Lars Hermann

    2016-01-01

    = 148; studies = 2; quality of evidence: very low). Included trials did not report on health-related quality of life (HRQoL), and the secondary outcomes of New York Heart Association class, left ventricular ejection fraction and cost. We did find that, compared with control (no exercise), exercise......BACKGROUND: Exercise-based cardiac rehabilitation may benefit heart valve surgery patients. We conducted a systematic review to assess the evidence for the use of exercise-based intervention programmes following heart valve surgery. OBJECTIVES: To assess the benefits and harms of exercise......: the Cochrane Central Register of Controlled Trials (CENTRAL); the Database of Abstracts of Reviews of Effects (DARE); MEDLINE (Ovid); EMBASE (Ovid); CINAHL (EBSCO); PsycINFO (Ovid); LILACS (Bireme); and Conference Proceedings Citation Index-S (CPCI-S) on Web of Science (Thomson Reuters) on 23 March 2015. We...

  7. Cardiac rehabilitation patient's perspectives on the recovery following heart valve surgery: a narrative analysis

    DEFF Research Database (Denmark)

    Hansen, Tina Birgitte; Zwisler, Ann Dorthe Olsen; Kikkenborg Berg, Selina

    2016-01-01

    , the participants expected to return to normality. The analysis identified four courses of recovery, with three non-linear complex pathways deviating from the classic restitution narrative: the frustrated struggle to resume normality, the challenged expectation of normality - being in a limbo and becoming a heart......AIMS: To explore the structure and content of narratives about the recovery process among patients undergoing heart valve surgery participating in cardiac rehabilitation. BACKGROUND: Several studies with short-term follow-up have shown that recovering from cardiac surgery can be challenging......, but evidence on the long-term recovery process is very limited, especially following heart valve surgery. Furthermore, few studies have explored the recovery process among cardiac rehabilitation participants. DESIGN: A qualitative study with serial interviews analysed using narrative methods. METHODS: We...

  8. Should the automatic exposure control system of CT be disabled when scanning patients with endoaortic stents or mechanical heart valves? A phantom study.

    Science.gov (United States)

    Di Leo, Giovanni; Spadavecchia, Chiara; Zanardo, Moreno; Secchi, Francesco; Veronese, Ivan; Cantone, Marie Claire; Sardanelli, Francesco

    2017-07-01

    To estimate the impact of endoaortic stents/mechanical heart valves on the output of an automatic exposure control (AEC) system and CT radiation dose. In this phantom study, seven stents and two valves were scanned with varying tube voltage (80/100/120 kVp), AEC activation (enabled/disabled) and prosthesis (present/absent), for a total of 540 scans. For each prosthesis, the dose-length product (DLP) was compared between scans with the AEC enabled and disabled. Percentage confidence levels for differences due to the prosthesis were calculated. Differences between results with the AEC enabled and disabled were not statistically significant (p ≥ 0.059). In the comparison with and without the prosthesis, DLP was unchanged at 80 kVp and 100 kVp, while a slight increase was observed at 120 kVp. The radiation dose varied from 1.8 mGy to 2.4 mGy without the prosthesis and from 1.8 mGy to 2.5 mGy with the prosthesis (confidence level 37-100%). The effect of the prosthesis on the AEC system was negligible and not clinically relevant. Therefore, disabling the AEC system when scanning these patients is not likely to provide a benefit. • CT-AEC system is not impaired in patients with endoaortic prostheses/heart valves. • Negligible differences may be observed only at 120 kVp. • Disabling the AEC system in these patients is not recommended.

  9. 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. © 2016 The Canadian College of Health Leaders.

  10. Natural Scaffolds for Regenerative Medicine: Direct Determination of Detergents Entrapped in Decellularized Heart Valves

    Directory of Open Access Journals (Sweden)

    Monica Dettin

    2017-01-01

    Full Text Available The increasing urgency for replacement of pathological heart valves is a major stimulus for research on alternatives to glutaraldehyde-treated grafts. New xenogeneic acellular heart valve substitutes that can be repopulated by host cells are currently under investigation. Anionic surfactants, including bile acids, have been widely used to eliminate the resident cell components chiefly responsible for the immunogenicity of the tissue, even if detergent toxicity might present limitations to the survival and/or functional expression of the repopulating cells. To date, the determination of residual detergent has been carried out almost exclusively on the washings following cell removal procedures. Here, a novel HPLC-based procedure is proposed for the direct quantification of detergent (cholate, deoxycholate, and taurodeoxycholate residues entrapped in the scaffold of decellularized porcine aortic and pulmonary valves. The method was demonstrated to be sensitive, reproducible, and extendable to different types of detergent. This assessment also revealed that cell-depleted heart valve scaffolds prepared according to procedures currently considered for clinical use might contain significant amount of surfactant.

  11. The future of heart valve banking and of homografts: perspective from the Deutsches Herzzentrum Berlin.

    Science.gov (United States)

    Delmo Walter, E M; de By, T M M H; Meyer, R; Hetzer, R

    2012-01-01

    Ever since the early days of homograft implantation in 1956, and the introduction into clinical practice by Ross and Barrat Boyes, homograft heart valves have proven to have many advantages. Its disadvantages became evident during long-term follow up. Factors, such as donor and recipient morbidity, tissue banking techniques, and the often complex surgical technique required to implant, are of great influence on the long term results. Because of European Directives, legally binding quality assurance regulations have been introduced in homograft banks. However, still not all processing methods have been scientifically sub-structured on their effects on the final product and its durability. The donor shortage has stimulated researchers and industries to develop and improve mechanical and biological valve substitutes such as the stentless bioprostheses. In general, candidates for homograft valve implantation include patients with: endocarditis, congenital defects and women who wish to become pregnant. For each category of patients different implantation techniques are required. The results of homograft banking and homograft transplantation in the German Heart Institute Berlin are satisfactory. Freedom of re-infection rate after homograft implantation is 91.9% +/- 3.6% after 15 years. Current developments show an increased interest in tissue engineered as well as in de- and re-cellularization of heart valve homografts. The advantages and disadvantages of the several processing techniques have not yet been proven in long term clinical results. For homograft bankers these developments pose as a challenge to join forces and to initiate cooperate projects aimed at scientific and organizational development.

  12. Antithrombotic therapy for stroke prevention in atrial fibrillation and mechanical heart valves.

    Science.gov (United States)

    Eikelboom, John W; Hart, Robert G

    2012-05-01

    Cardioembolic strokes account for one-sixth of all strokes and are an important potentially preventable cause of morbidity and mortality. Vitamin K antagonists (e.g., warfarin) are effective for the prevention of cardioembolic stroke in patients with atrial fibrillation (AF) and in those with mechanical heart valves but because of their inherent limitations are underutilized and often suboptimally managed. Antiplatelet therapies have been the only alternatives to warfarin for stroke prevention in AF but although they are safer and more convenient they are much less efficacious. The advent of new oral anticoagulant drugs offers the potential to reduce the burden of cardioembolic stroke by providing access to effective, safe, and more convenient therapies. New oral anticoagulants have begun to replace warfarin for stroke prevention in some patients with AF, based on the favorable results of recently completed phase III randomized controlled trials, and provide for the first time an alternative to antiplatelet therapy for patients deemed unsuitable for warfarin. The promise of the new oral anticoagulants in patients with mechanical heart valves is currently being tested in a phase II trial. If efficacy and safety are demonstrated, the new oral anticoagulants will provide an alternative to warfarin for patients with mechanical heart valves and may also lead to increased use of mechanical valves for patients who would not have received them in the past because of the requirement for long term warfarin therapy. Copyright © 2012 Wiley Periodicals, Inc.

  13. Characterization of acid and non-acid glycosphingolipids of porcine heart valve cusps as potential immune targets in biological heart valve grafts.

    Science.gov (United States)

    Barone, Angela; Benktander, John; Teneberg, Susann; Breimer, Michael E

    2014-01-01

    Although xenotransplantation of vascularized organs/cells has not yet reached the clinic, glutaraldehyde-treated bioprosthetic heart valves (BHV), derived from porcine or bovine tissues, are today used for clinical replacement of diseased heart valves. However, the durability of these valve cusps is limited partly due to the onset of immune responses to the grafts. The xenoantigen-determinant Galα3Gal- and corresponding anti-Gal antibodies have been postulated to in part contribute to BHV damage. However, the presence of other non-Gal carbohydrate antigen determinants as well as the immune response to these non-Gal antigens and the inflammatory response generated by their interaction with the immune system has not been studied. In this study, we have isolated and structurally characterized both non-acid and acid glycosphingolipids from naïve porcine aortic and pulmonary valve cusps. Total non-acid and acid glycosphingolipids were isolated from porcine aortic and pulmonalis valve cusps of 20 animals. Glycosphingolipid components were structurally characterized by thin-layer chromatography, liquid chromatography-mass spectrometry and binding of monoclonal antibodies and lectins. The non-acid glycosphingolipids were characterized as globotetraosylceramide, H-type 2 pentaosylceramide, fucosyl-gangliotetraosylceramide, and Galα3neolactotetraosylceramide. The acid glycosphingolipid fractions had both sulfatide and gangliosides (GM3, GM2, GM1, fucosyl-GM1, GD3 and GD1a), and all gangliosides contained N-acetyl-neuraminic acid. Significantly, the N-glycolyl-neuraminic acid (NeuGc) variant, a major component in many pig organs and to which humans can develop antibodies, was not detected among the gangliosides. Pig valve cusps contain several complex lipid-bound carbohydrate structures that may be targets for the human immune system. Notable, the NeuGc determinant was absent in the cusp gangliosides. This work forms a platform for further characterizing the antibody

  14. Decellularized allogeneic heart valves demonstrate self-regeneration potential after a long-term preclinical evaluation.

    Directory of Open Access Journals (Sweden)

    Laura Iop

    Full Text Available Tissue-engineered heart valves are proposed as novel viable replacements granting longer durability and growth potential. However, they require extensive in vitro cell-conditioning in bioreactor before implantation. Here, the propensity of non-preconditioned decellularized heart valves to spontaneous in body self-regeneration was investigated in a large animal model. Decellularized porcine aortic valves were evaluated for right ventricular outflow tract (RVOT reconstruction in Vietnamese Pigs (n = 11 with 6 (n = 5 and 15 (n = 6 follow-up months. Repositioned native valves (n = 2 for each time were considered as control. Tissue and cell components from explanted valves were investigated by histology, immunohistochemistry, electron microscopy, and gene expression. Most substitutes constantly demonstrated in vivo adequate hemodynamic performances and ex vivo progressive repopulation during the 15 implantation months without signs of calcifications, fibrosis and/or thrombosis, as revealed by histological, immunohistochemical, ultrastructural, metabolic and transcriptomic profiles. Colonizing cells displayed native-like phenotypes and actively synthesized novel extracellular matrix elements, as collagen and elastin fibers. New mature blood vessels, i.e. capillaries and vasa vasorum, were identified in repopulated valves especially in the medial and adventitial tunicae of regenerated arterial walls. Such findings correlated to the up-regulated vascular gene transcription. Neoinnervation hallmarks were appreciated at histological and ultrastructural levels. Macrophage populations with reparative M2 phenotype were highly represented in repopulated valves. Indeed, no aspects of adverse/immune reaction were revealed in immunohistochemical and transcriptomic patterns. Among differentiated elements, several cells were identified expressing typical stem cell markers of embryonic, hematopoietic, neural and mesenchymal lineages in significantly

  15. Multi-scale mechanical characterization of scaffolds for heart valve tissue engineering.

    Science.gov (United States)

    Argento, G; Simonet, M; Oomens, C W J; Baaijens, F P T

    2012-11-15

    Electrospinning is a promising technology to produce scaffolds for cardiovascular tissue engineering. Each electrospun scaffold is characterized by a complex micro-scale structure that is responsible for its macroscopic mechanical behavior. In this study, we focus on the development and the validation of a computational micro-scale model that takes into account the structural features of the electrospun material, and is suitable for studying the multi-scale scaffold mechanics. We show that the computational tool developed is able to describe and predict the mechanical behavior of electrospun scaffolds characterized by different microstructures. Moreover, we explore the global mechanical properties of valve-shaped scaffolds with different microstructural features, and compare the deformation of these scaffolds when submitted to diastolic pressures with a tissue engineered and a native valve. It is shown that a pronounced degree of anisotropy is necessary to reproduce the deformation patterns observed in the native heart valve. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. In vitro susceptibility of high virulence microorganisms isolated in heart valve banking.

    Science.gov (United States)

    Villalba, R; Solis, F; Fornés, G; Jimenez, A; Eisman, M; González, Ana I; Linares, M J; Casal, M; Gómez Villagrán, J L

    2012-08-01

    Storage preparation of human heart valves for implants generally includes incubation in an antimicrobial disinfection solution and cryopreservation. Changes in patterns of microorganisms susceptibility to antibiotics is a variable process of that promote its inefficiency. The aim of this study has been an evaluation of in vitro susceptibility of high virulence microorganisms isolated in our tissue bank for 14 years in order to evaluate the efficiency, and to promote changes for further antibiotics mixtures as well. Data presented in this study show that microorganisms isolates in valve banking display susceptibility patterns similar to those shown in other clinical circumstances, and the most commonly used antibiotics regimes are useful to date. An antibiotic cocktail containing aminoglicoside in addition to ciprofloxacin and vancomycin is an efficient mixture to be used in valve banking. Further studies will be necessary for monitoring patterns changes of in vitro susceptibility of microbiological isolates in tissue banking.

  17. Simulations of the hinge micro flow field of a bileaflet mechanical heart valve

    Science.gov (United States)

    Simon, Helene; Ge, Liang; Sotiropoulos, Fotis; Yoganathan, Ajit

    2006-11-01

    Studies have shown that bileaflet mechanical heart valves (BMHV) promote blood cell damage and thromboembolic events due to their non-physiologic hemodynamics. Clinical reports and recent in-vitro experiments suggest that these complications are mainly associated with the hemodynamic stresses of flow through the valve hinge regions. To date, hinge hemodynamics has been largely studied using experimental approaches. This study aims at numerically simulating the pulsatile flow through the hinge region of a BMHV. The numerical technique uses a Cartesian sharp interface immersed boundary methodology and a hybrid staggered/non staggered control volume method. The hinge and leaflet dimensions are obtained from Micro Computed Tomography of an actual clinical bileaflet valve and the leaflet motion is provided as prescribed boundary conditions based on experimental measurements. Calculations will be presented for pulsatile flow conditions and reveal a complex three dimensional flow pattern throughout the entire cardiac cycle.

  18. Porcine vena cava as an alternative to bovine pericardium in bioprosthetic percutaneous heart valves.

    Science.gov (United States)

    Munnelly, Amy E; Cochrane, Leonard; Leong, Joshua; Vyavahare, Naren R

    2012-01-01

    Percutaneous heart valves are revolutionizing valve replacement surgery by offering a less invasive treatment option for high-risk patient populations who have previously been denied the traditional open chest procedure. Percutaneous valves need to be crimped to accommodate a small-diameter catheter during deployment, and they must then open to the size of heart valve. Thus the material used must be strong and possess elastic recoil for this application. Most percutaneous valves utilize bovine pericardium as a material of choice. One possible method to reduce the device delivery diameter is to utilize a thin, highly elastic tissue. Here we investigated porcine vena cava as an alternative to bovine pericardium for percutaneous valve application. We compared the structural, mechanical, and in vivo properties of porcine vena cava to those of bovine pericardium. While the extracellular matrix fibers of pericardium are randomly oriented, the vena cava contains highly aligned collagen and elastin fibers that impart strength to the vessel in the circumferential direction and elasticity in the longitudinal direction. Moreover, the vena cava contains a greater proportion of elastin, whereas the pericardium matrix is mainly composed of collagen. Due to its high elastin content, the vena cava is significantly less stiff than the pericardium, even after crosslinking with glutaraldehyde. Furthermore, the vena cava's mechanical compliance is preserved after compression under forces similar to those exerted by a stent, whereas pericardium is significantly stiffened by this process. Bovine pericardium also showed surface cracks observed by scanning electron microscopy after crimping that were not seen in vena cava tissue. Additionally, the vena cava exhibited reduced calcification (46.64 ± 8.15 μg Ca/mg tissue) as compared to the pericardium (86.79 ± 10.34 μg/mg). These results suggest that the vena cava may provide enhanced leaflet flexibility, tissue resilience, and tissue

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

    Science.gov (United States)

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

    2017-10-24

    Transcatheter heart valve (THV) thrombosis has been increasingly reported. In these studies, thrombus quantification has been based on a 2-dimensional assessment of a 3-dimensional phenomenon. Postprocedural, 4-dimensional, volume-rendered CT data of patients with CoreValve, Evolut R, and SAPIEN 3 transcatheter aortic valve replacement enrolled in the RESOLVE study (Assessment of Transcatheter and Surgical Aortic Bioprosthetic Valve Dysfunction With Multimodality Imaging and Its Treatment with Anticoagulation) were included in this analysis. Patients on anticoagulation were excluded. SAPIEN 3 and CoreValve/Evolut R patients with and without hypoattenuated leaflet thickening were included to study differences between groups. Patients were classified as having THV thrombosis if there was any evidence of hypoattenuated leaflet thickening. Anatomic and THV deployment geometries were analyzed, and thrombus volumes were computed through manual 3-dimensional reconstruction. We aimed to identify and evaluate risk factors that contribute to THV thrombosis through the combination of retrospective clinical data analysis and in vitro imaging in the space between the native and THV leaflets (neosinus). SAPIEN 3 valves with leaflet thrombosis were on average 10% further expanded (by diameter) than those without (95.5±5.2% versus 85.4±3.9%; P<0.001). However, this relationship was not evident with the CoreValve/Evolut R. In CoreValve/Evolut Rs with thrombosis, the thrombus volume increased linearly with implant depth (R2=0.7, P<0.001). This finding was not seen in the SAPIEN 3. The in vitro analysis showed that a supraannular THV deployment resulted in a nearly 7-fold decrease in stagnation zone size (velocities <0.1 m/s) when compared with an intraannular deployment. In addition, the in vitro model indicated that the size of the stagnation zone increased as cardiac output decreased. Although transcatheter aortic valve replacement thrombosis is a multifactorial process

  20. Risk factors for heart valve calcification in chronic kidney disease.

    Science.gov (United States)

    Rong, Shu; Qiu, Xin; Jin, Xiucai; Shang, Minghua; Huang, Yixin; Tang, Zhihuan; Yuan, Weijie

    2018-02-01

    Cardiovascular disease (CVD) is a common cause of death in patients with chronic kidney disease (CKD). Aortic and mitral valve calcification (AVC and MVC, respectively) are critical indicators of CVD and all-cause mortality in CKD patients.We conducted a single center retrospective study of Chinese inpatients with CKD to identify risk factors associated with valve calcification (VC).Of 288 enrolled CKD patients, 22.9% had VC, all of which exhibited AVC, while 21.2% exhibited MVC. The VC group were significantly older than the non-VC group (70.42 ± 11.83 vs 56.47 ± 15.00, P < .001), and contained more patients with history of coronary artery disease (12.1% vs 4.5%, P = .025) or stroke (18.2% vs 5.4%, P < .001). Subjective global assessment scoring indicated that more VC patients were mid/severely malnourished. Levels of prealbumin, cholesterol (Ch), triglycerides, low-density lipoprotein (LDL), apolipoprotein E, ejection fraction, and fraction shortening were significantly lower, and blood C reactive protein, IL-6, left ventricular internal end diastole diameter measured in end diastole, and interventricular septum thickness (IVST) levels were significantly higher in the VC group. Bone metabolism did not differ significantly between the 2 groups. Multivariable logistic regression analysis indicated that age, blood Ch, and LDL levels were significantly associated with VC.Advanced age, increased IVST, hypocholesterolemia, and hyper-LDL cholesterolemia were key risk factors for VC in Han patients with CKD.

  1. Obstructive Thrombosis of Left-Sided Mechanical Heart Valves: Clinical Profile and Thrombolytic Therapy.

    Science.gov (United States)

    Chandrakasu, Arumugam; Jayachandran, Avinash; Gopinath Nayar, Pradeep; Meyyappan, Chokkalingam; Narayan, Ganesh; Basha Abdul Bari, Ahamed; Johnson Samuel, Prince

    2017-05-01

    Thrombosis of a mechanical prosthetic heart valve is a potentially life-threatening complication associated with a high mortality. Although thrombolytic therapy has been considered highly beneficial in this situation, very few studies have been conducted to monitor the effectiveness of such thrombolytic therapy among Asian populations. Hence, the study aim was to evaluate the clinical profile, efficacy and safety of the thrombolytic agent streptokinase (SK) in patients with obstructive thrombosis of a left-sided mechanical heart valve. Patients (n = 30) with left-sided mechanical heart valve thrombosis (LSMHVT) who had been managed with SK during the past four years were included in this retrospective study. Clinical features such as presenting symptoms based on NYHA functional class, prosthetic valve position, oral anticoagulant compliance, International Normalized Ratio (INR) and imaging methods including fluoroscopy, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were evaluated. In addition, the effectiveness and complications of SK were analyzed. The majority of patients presented with advanced NYHA class (III and IV, each 40%). Obstructive thromboses were observed at the mitral prosthesis in 70% of cases, at the aortic prosthesis in 27%, and at both valves in 3%. All patients underwent TTE, but fluoroscopy was used more often than TEE. Despite compliance with oral anticoagulation therapy, a sub-therapeutic INR was observed in 40% of cases at the time of presentation. Overall, thrombolysis was successful in 80% of patients using intravenous SK, with 100% success in patients in NYHA classes I-III and 42% for NYHA class IV. Moreover, embolic complications occurred in only a small number of patients. In patients with obstructive thrombosis of LSMHVT, intravenous SK was effective and should be considered as first choice in patients in NYHA classes I-III, and as an acceptable alternative in those in NYHA class IV.

  2. Sleep-Disordered Breathing in Patients with Pulmonary Valve Incompetence Complicating Congenital Heart Disease.

    Science.gov (United States)

    Miles, Susan; Ahmad, Waheed; Bailey, Amy; Hatton, Rachael; Boyle, Andrew; Collins, Nicholas

    2016-12-01

    Long standing pulmonary regurgitation results in deleterious effects on right heart size and function with late consequences of right heart volume overload including ventricular dilatation, propensity to arrhythmia and right heart failure. As sleep disordered breathing may predispose to elevations in pulmonary vascular resistance and associated negative effects on right ventricular function, we sought to assess this in patients with underlying congenital heart disease. We performed a pilot study to evaluate the incidence of sleep-disordered breathing in a patient population with a history of long standing pulmonary valve incompetence in patients with congenital heart disease using overnight oximetry. Patients with a background of tetralogy of Fallot repair or residual pulmonary incompetence following previous pulmonary valve intervention for congenital pulmonary stenosis were included. Twenty-two patients underwent overnight oximetry. The mean age of the cohort was 34.3 ± 15.2 years with no patients observed to have severe underlying pulmonary hypertension. Abnormal overnight oximetry was seen in 13/22 patients (59.1%) with 2/22 (9.1%) patients considered to have severe abnormalities. An important proportion of patients with a background of pulmonary incompetence complicating congenital heart disease are prone to the development of sleep-disordered breathing as assessed by overnight oximetry. Further study into the prevalence and mechanisms of sleep-disordered breathing in a larger cohort are warranted. © 2016 Wiley Periodicals, Inc.

  3. Right heart chamber geometry and tricuspid annulus morphology in patients undergoing mitral valve repair with and without tricuspid valve annuloplasty.

    Science.gov (United States)

    Tamborini, Gloria; Fusini, Laura; Muratori, Manuela; Gripari, Paola; Ghulam Ali, Sarah; Fiorentini, Cesare; Pepi, Mauro

    2016-06-01

    According to current recommendations, patients could benefit from tricuspid valve (TV) annuloplasty at the time mitral valve (MV) surgery if tricuspid regurgitation is severe or if tricuspid annulus (TA) dilatation is present. Therefore, an accurate pre-operative echocardiographic study is mandatory for left but also for right cardiac structures. Aims of this study are to assess right atrial (RA), right ventricular (RV) and TA geometry and function in patients undergoing MV repair without or with TV annuloplasty. We studied 103 patients undergoing MV surgery without (G1: 54 cases) or with (G2: 49 cases) concomitant TV annuloplasty and 40 healthy subjects (NL) as controls. RA, RV and TA were evaluated by three-dimensional (3D) transthoracic echocardiography. Comparing the pathological to the NL group, TA parameters and 3D right chamber volumes were significantly larger. RA and RV ejection fraction and TA% reduction were lower in pathological versus NL, and in G2 versus G1. In pathological patients, TA area positively correlated to systolic pulmonary pressure and negatively with RV and RA ejection fraction. Patients undergoing MV surgery and TV annuloplasty had an increased TA dimensions and a more advanced remodeling of right heart chambers probably reflecting an advanced stage of the disease.

  4. Tissue engineering of heart valves: PEGylation of decellularized porcine aortic valve as a scaffold for in vitro recellularization.

    Science.gov (United States)

    Zhou, Jianliang; Hu, Shidong; Ding, Jingli; Xu, Jianjun; Shi, Jiawei; Dong, Nianguo

    2013-09-05

    Poly (ethylene glycol) (PEG) has attracted broad interest for tissue engineering applications. The aim of this study was to synthesize 4-arm -PEG-20kDa with the terminal group of diacrylate (4-arm-PEG-DA) and evaluate its dual functionality for decellularized porcine aortic valve (DAV) based on its mechanical and biological properties. 4-arm-PEG-DA was synthesized by graft copolymerization of linear PEG 20,000 monomers, and characterized by IR1H NMR and 13C NMR; PEGylation of DAV was achieved by the Michael addition reaction between propylene acyl and thiol, its effect was tested by uniaxial planar tensile testing, hematoxylin and eosin (HE) and scanning electron microscopy (SEM). Gly-Arg-Gly-Asp-Ser-Pro-Cys (GRGDSPC) peptides and vascular endothelial growth factor-165 (VEGF165) were conjugated onto DAV by branched PEG-DA (GRGDSPC-PEG-DAV-PEG-VEGF165). Mechanical testing confirmed that PEG-cross-linking significantly enhanced the tensile strength of DAV. Immunofluoresce confirmed the GRGDSPC peptides and VEGF165 were conjugated effectively onto DAV; the quantification of conjunction was completed roughly using spectrophotometry and ELISA. The human umbilical vein endothelial cells (HUVECs) grew and spread well on the GRGDSPC-PEG-DAV-PEG-VEGF165. Therefore, PEGylation of DAV not only can improve the tensile strength of DAV, and can also mediate the conjugation of bioactive molecule (VEGF165 and GRGDSPC peptides) on DAV, which might be suitable for further development of tissue engineered heart valve.

  5. 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

  6. Engineering of a bio-functionalized hybrid off-the-shelf heart valve.

    Science.gov (United States)

    Hinderer, Svenja; Seifert, Jan; Votteler, Miriam; Shen, Nian; Rheinlaender, Johannes; Schäffer, Tilman E; Schenke-Layland, Katja

    2014-02-01

    Currently available heart valve replacements are limited in long-term performance or fail due to leaflet thickening, lack of growth or remodeling potential. In order to address these issues, it is necessary to mimic multiple factors of the native valvular extracellular matrix (ECM) such as architecture, mechanical behavior and biochemical signals. Here, we successfully generated an electrospun PEGdma-PLA scaffold adapted to the structure and mechanical properties of native valve leaflets. Valvular interstitial cells (VICs) and valvular endothelial cells (VECs) were seeded on the scaffold and when cultured under physiological conditions in a bioreactor, the construct performed like a native leaflet. Atomic force microscopy (AFM) was employed to obtain detailed mechanical information from the leaflets, which enabled the first layer-specific measurement of the Young's modulus. Interestingly, spongiosa stiffness was much lower compared to the fibrosa and ventricularis. Moreover, investigations into human fetal heart valve development identified collagen type I and versican as important structural proteins. As a proof of principle, these proteins were introduced to the scaffold, demonstrating the ability to bio-functionalize the hybrid valve based on natures' blueprint. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Identification of critical zones in the flow through prosthetic heart valves

    Science.gov (United States)

    Lopez, A.; Ledesma, R.; Zenit, R.; Pulos, G.

    2008-11-01

    The hemodynamic properties of prosthetic heart valves can cause blood damage and platelet activation due to the non- physiological flow patterns. Blood recirculation and elevated shear stresses are believed to be responsible for these complications. The objective of this study is to identify and quantify the conditions for which recirculation and high stress zones appear. We have performed a comparative study between a mechanical monoleaflet and biological valve. In order to generate the flow conditions to test the prosthesis, we have built a hydraulic circuit which reproduces the human systemic circulation, on the basis of the Windkessel model. This model is based on an electrical analogy which consists of an arterial resistance and compliance. Using PIV 3D- Stereo measurements, taken downstream from the prosthetic heart valves, we have reconstructed the full phase-averaged tridimensional velocity field. Preliminary results show that critical zones are more prominent in mechanical prosthesis, indicating that valves made with bio-materials are less likely to produce blood trauma. This is in accordance with what is generally found in the literature.

  8. Fluid-structure interaction in the left ventricle of the human heart coupled with mitral valve

    Science.gov (United States)

    Meschini, Valentina; de Tullio, Marco Donato; Querzoli, Giorgio; Verzicco, Roberto

    2016-11-01

    In this paper Direct Numerical Simulations (DNS), implemented using a fully fluid-structure interaction model for the left ventricle, the mitral valve and the flowing blood, and laboratory experiments are performed in order to cross validate the results. Moreover a parameter affecting the flow dynamics is the presence of a mitral valve. We model two cases, one with a natural mitral valve and another with a prosthetic mechanical one. Our aim is to understand their different effects on the flow inside the left ventricle in order to better investigate the process of valve replacement. We simulate two situations, one of a healthy left ventricle and another of a failing one. While in the first case the flow reaches the apex of the left ventricle and washout the stagnant fluid with both mechanical and natural valve, in the second case the disturbance generated by the mechanical leaflets destabilizes the mitral jet, thus further decreasing its capability to penetrate the ventricular region and originating heart attack or cardiac pathologies in general.

  9. Anatomic variations of the cardiac valves and papillary muscles of the right heart.

    Science.gov (United States)

    Xanthos, Theodoros; Dalivigkas, Ioannis; Ekmektzoglou, Konstantinos A

    2011-01-01

    This article reviews the right atrioventricular and pulmonary valves, along with their anatomic variations as well as the papillary muscles and chordae tendineae of the right ventricle of the human heart. A brief anatomical background is given for every structure, as well as a gross review of their embryological basis. Although the normal morphology of the right atrioventricular valve is tricuspid, this is not always the case; its anatomic variations involve, firstly, the number of cusps and accessory leaflets. Anatomic variations of the right atrioventricular valve may occur in association with other congenital anomalies and syndromes. Also the number, length and shape of the papillary muscles and chordae tendineae are variable. This can be of clinical significance since the papillary muscles play an important role in the contraction of the right ventricle and in the closure of the tricuspid valve so as to prevent ventricular blood from passing back into the right atrium. The pulmonary valve may present variations in the number of cusps, stenosis or atresia, either as isolated clinical findings or in association with congenital syndromes.

  10. 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.

  11. In vitro assessment of a new algorithm for quantitative echo measurement of heart valve regurgitant jet

    Science.gov (United States)

    Grigioni, Mauro; Tonti, Gianni; Pedrizzetti, Gianni; Daniele, Carla; D'Avenio, Giuseppe

    2003-05-01

    The measure of the regurgitant flow through heart valves provides an indication of the severity of the valve closure dysfunction with diagnostic relevance. The estimation of the volume passing through the closed valve during systole, and its ratio with the ejection volume, can significantly improve the assessment of an ongoing valvular pathology. The noninvasive quantification of flow converging to the valve is still lacking a satisfying degree of precision. The most popular technique is the Proximal Isovelocity Surface Area (PISA), which assumes that, in the flow field upstream of the valve, the surfaces corresponding to the same velocity are spherical, whence the regurgitant flow is estimated by multiplication with the hemispherical surface area. In the present study, a new method is proposed of color Doppler echocardiography image processing, for regurgitant flow measurements. In this method, called Proximal Arbitrary Surface Conservative Assessment of Leakage (PASCAL), the laws of fluid dynamics are used to reconstruct the entire flow field, in the hypothesis of axial symmetry, starting from the echographic Doppler mapping of one component of velocity. In vitro experiments have confirmed that the new method provides better flow estimates than PISA, on account of its more rigorous physical model of the regurgitant flow.

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    Daphne van Geemen

    Full Text Available 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.

  14. [Percutaneous catheter-based implantation of artificial pulmonary valves in patients with congenital heart defects].

    Science.gov (United States)

    Wyller, Vegard Bruun; Aaberge, Lars; Thaulow, Erik; Døhlen, Gaute

    2011-07-01

    Percutaneous catheter-based implantation of artificial heart valves is a new technique that may supplement surgery and which may be used more in the future. We here report our first experience with implantation of artificial pulmonary valves in children with congenital heart defects. Eligible patients were those with symptoms of heart failure combined with stenosis and/or insufficiency in an established artificial right ventricular outflow tract. The valve was inserted through a catheter from a vein in the groin or neck. Symptoms, echocardiography, invasive measurements and angiography were assessed for evaluation of treatment effect. Our treatment results are reported for the period April 2007-September 2009. Ten patients (seven men and three women, median age 17 years) were assessed. The procedure reduced pressure in the right ventricle (p = 0.008) and resolved the pulmonary insufficiency in all patients. The median time in hospital was two days. No patients had complications that were directly associated with the implantation procedure. One patient developed a pseudoaneurysm in the femoral artery, another had a short-lasting fever two days after the procedure and one patient experienced a stent fracture that required surgery 9 months after the implantation. After 6 months all patients had a reduced pressure gradient in the right ventricular outflow tract (p = 0.008), the pulmonary insufficiency had improved (p = 0.006) and they all reported improval of symptoms. These results persisted for at least 24 months for the four patients who were monitored until then. Percutaneous catheter-based implantation of artificial pulmonary valves improves hemodynamics in the right ventricle of selected patients with congenital heart defects. A randomized controlled study should be undertaken to provide a stronger evidence-base for usefulness of this procedure.

  15. Anti-Coagulation During Pregnancy in Women with Mechanical Heart Valves: A Prospective Study

    Directory of Open Access Journals (Sweden)

    Amir Jamshid Khamoushi

    2011-01-01

    Full Text Available Background: Pregnancy is associated with a hypercoagulable state, therefore the optimalanticoagulants for potential use in pregnant women with prosthetic heart valves are controversial.The aim of this study is to investigate the effect of anticoagulants on pregnancy outcomes and theirpotential risks in pregnant women with mechanical heart valves.Materials and Methods: In this prospective cohort study, we followed 44 women with 49pregnancies who had mechanical heart valves from September 2002 to September 2007. A totalof 38 patients took warfarin throughout their pregnancies (group A. In 11 patients, warfarin waschanged to heparin during the first trimester and then again to warfarin during 12th to 36th weeksof gestational age (group B. All women took warfarin from 36th weeks of gestational age untildelivery.Results: In group A, there were 22 live births (57.9%, 15 abortions (39.5% and 1 maternal death(2.6%. In group B, there were seven live births (63.6%, three spontaneous abortions (27.3% andone intra-uterine fetal death (9.1%. There was no significant difference in live birth rate betweenthe two groups (p=0.24. Thirty-three pregnancies (86.8% in group A and five pregnancies (45.4%in group B had no maternal complications (p=0.004. The difference in pregnancy complicationsbetween both groups was significant (p<0.001Conclusion: The present study shows that low dose warfarin (5 mg/day or less may be safeduring the first trimester of pregnancy. Maternal adverse events are low when pregnant womenwith mechanical heart valves remain on a warfarin regimen. The risk of embryopathy does notnecessarily increase.

  16. Current Perioperative Anticoagulation Practices in Children with Prosthetic Mechanical Heart Valves.

    Science.gov (United States)

    Nguyen, Nguyenvu; Sharathkumar, Anjali

    2015-01-01

    This study investigated the clinician practices on perioperative anticoagulation in children with prosthetic mechanical heart valves who undergo elective surgeries. An online survey was administered to members of PediHeartNet. The survey consisted of multiple choice questions and clinical scenarios. The study described clinical practice patterns and variables that influence the clinicians' bridging anticoagulation decisions. Ninety-one respondents completed the survey; 68% were affiliated with university settings; 91% were pediatric cardiologists, and 49% had ≥10 years of experience in pediatric cardiology. Approximately one-half of the respondents (54%) independently provided perioperative anticoagulation management to their patients, while 46% utilized cardiac or hematology anticoagulation services. Resources that influenced bridging decisions included hematology experts (20%), American College of Chest Physicians guidelines (34%), and the clinicians' personal experience (56%). In planning for major surgeries, 47% of the respondents hospitalized patients for unfractionated heparin (UFH) and 46% prescribed outpatient low molecular weight heparin (LMWH). For minor surgeries, 58% hospitalized patients for UFH, 22% prescribed outpatient LMWH, and 17% opted out of bridging anticoagulation. Immediately after mitral valve replacement, 23% used bridging anticoagulation with UFH. When LMWH was used, there were no reports of thromboembolic complications. Major bleeding complications were rare and reported by 2% of the respondents. This was the first documentation that clinical practice of bridging perioperative anticoagulation in children with mechanical heart valves varies widely among pediatric cardiac specialists. There is poor adoption of published guidelines and a tendency toward more conservative strategies. Further studies comparing the safety and efficacy of LMWH vs. UFH as perioperative anticoagulation agents in children with mechanical heart valves are needed

  17. A prospective study of an aggressive warfarin dosing algorithm to reach and maintain INR 2 to 3 after heart valve surgery

    NARCIS (Netherlands)

    Meijer, Karina; Kim, Yang-Ki; Carter, Donna; Schulman, Sam

    Good anticoagulation control in patients during the first months after heart valve surgery is important to prevent thrombotic complications. This is difficult to achieve, partly because the sensitivity to warfarin decreases progressively during approximately three months after valve surgery. A

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

    Energy Technology Data Exchange (ETDEWEB)

    Ye Xia [Center of Photonics Fabrication, Jiangsu University, Zhenjiang 212013 (China); School of Mechanical Engineering, Jiangsu Teachers University of Technology, Changzhou 213015 (China); Shao Yunliang [Center of Photonics Fabrication, Jiangsu University, Zhenjiang 212013 (China); Zhou Ming, E-mail: zm_laser@126.com [Center of Photonics Fabrication, Jiangsu University, Zhenjiang 212013 (China); Li Jian; Cai Lan [Center of Photonics Fabrication, Jiangsu University, Zhenjiang 212013 (China)

    2009-04-15

    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 {mu}m in underside diameter and 3 {mu}m 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.

  19. Backpropagation artificial neural network classifier to detect changes in heart sound due to mitral valve regurgitation.

    Science.gov (United States)

    Sinha, Rakesh Kumar; Aggarwal, Yogender; Das, Barda Nand

    2007-06-01

    The phonocardiograph (PCG) can provide a noninvasive diagnostic ability to the clinicians and technicians to compare the heart acoustic signal obtained from normal and that of pathological heart (cardiac patient). This instrument was connected to the computer through the analog to digital (A/D) converter. The digital data stored for the normal and diseased (mitral valve regurgitation) heart in the computer were decomposed through the Coifman 4th order wavelet kernel. The decomposed phonocardiographic (PCG) data were tested by backpropagation artificial neural network (ANN). The network was containing 64 nodes in the input layer, weighted from the decomposed components of the PCG in the input layer, 16 nodes in the hidden layer and an output node. The ANN was found effective in differentiating the wavelet components of the PCG from mitral valve regurgitation confirmed person (93%) to normal subjects (98%) with an overall performance of 95.5%. This system can also be used to detect the defects in cardiac valves especially, and other several cardiac disorders in general.

  20. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  2. Comparing Direct Oral Anticoagulants and Warfarin for Atrial Fibrillation, Venous Thromboembolism, and Mechanical Heart Valves.

    Science.gov (United States)

    Marcy, Todd R; Truong, Teresa; Rai, Andrea

    2015-11-01

    To summarize available data for use of direct oral anticoagulants in nonvalvular atrial fibrillation, venous thromboembolism, and mechanical heart valves including dose-response consistency to offer considerations for pharmacotherapeutic decision-making for oral anticoagulants. A Medline search of English-language studies published between 2000 and March 2015 was conducted to identify pertinent papers using combinations of the following words: apixaban, atrial fibrillation, dabigatran, direct oral anticoagulant, edoxaban, factor IIa inhibitors, factor Xa inhibitors, mechanical heart valves, novel oral anticoagulant, rivaroxaban, venous thromboembolism, and warfarin. Original studies, guidelines, and approved prescribing information were evaluated and included if contributing new or complementary data toward the objective. References for all identified studies were reviewed and entries included if contributory. Randomized controlled trials have established the safety and efficacy of direct oral anticoagulants in atrial fibrillation and venous thromboembolism for most patient groups. Direct oral anticoagulants should not be used in patients with mechanical heart valves until proven safe and effective. There are groups for which questions remain regarding inter-patient dose-response consistency for direct oral anticoagulants. There are postmarketing data suggesting poorer real-world performance of dabigatran relative to clinical trial data. Direct oral anticoagulants offer several advantages over warfarin, and large clinical trial data establish the appropriateness of their use in broad populations. There remain groups for whom the relative benefit and risk of these agents relative to warfarin are uncertain. A patient-specific approach in pharmacotherapeutic decision-making is appropriate.

  3. Experimental Validation of a Cardiac Simulator for in vitro Evaluation of Prosthetic Heart Valves

    Directory of Open Access Journals (Sweden)

    Ovandir Bazan

    Full Text Available Abstract Objective: This work describes the experimental validation of a cardiac simulator for three heart rates (60, 80 and 100 beats per minute, under physiological conditions, as a suitable environment for prosthetic heart valves testing in the mitral or aortic position. Methods: In the experiment, an aortic bileaflet mechanical valve and a mitral bioprosthesis were employed in the left ventricular model. A test fluid of 47.6% by volume of glycerin solution in water at 36.5ºC was used as blood analogue fluid. A supervisory control and data acquisition system implemented previously in LabVIEW was applied to induce the ventricular operation and to acquire the ventricular signals. The parameters of the left ventricular model operation were based on in vivo and in vitro data. The waves of ventricular and systemic pressures, aortic flow, stroke volume, among others, were acquired while manual adjustments in the arterial impedance model were also established. Results: The acquired waves showed good results concerning some in vivo data and requirements from the ISO 5840 standard. Conclusion: The experimental validation was performed, allowing, in future studies, characterizing the hydrodynamic performance of prosthetic heart valves.

  4. The Vietnamese pig as a translational animal model to evaluate tissue engineered heart valves: promising early experience.

    Science.gov (United States)

    Gallo, Michele; Poser, Helen; Bottio, Tommaso; Bonetti, Antonella; Franci, Paolo; Naso, Filippo; Buratto, Edward; Zanella, Fabio; Perona, Giovanni; Dal Lin, Carlo; Bianco, Roberto; Spina, Michele; Busetto, Roberto; Marchini, Maurizio; Ortolani, Fulvia; Iop, Laura; Gerosa, Gino

    2017-05-09

    Several animal models are currently used for the surgical implantation of either biologic or biopolymeric scaffolds in order to provide in vivo assessment of tissue-engineered heart valves. The Vietnamese pig (VP) is herein proposed as a suitable recipient to test the function of novel bioengineered valve substitutes, in the reconstruction of the right ventricular outflow tract (RVOT). This review aims to provide a complete and exhaustive panel of physiological parameters and methodological information for preclinical studies of tissue-engineered heart valves in the VP animal model.

  5. The design and development of a stented tissue mitral and aortic heart valve replacement for human implantation.

    Science.gov (United States)

    Legg, Murray; Mathews, Edward; Pelzer, Ruaan

    2012-04-01

    A study was conducted into the development of a mitral and aortic heart valve replacement that caters for patients having suffered valve damage due to stenosis or rheumatic fever. The appeal of the valve is that it is constituted from a solid frame housing pericardial tissue leaflets, and allows the patient freedom from post-operative blood-thinning medication. The valve is designed to appeal to patients in developing areas of the world, as it features a clip-in mechanism to secure the valve assembly into the sewing ring, which is stitched in independently of the frame and leaflets. Re-operative valve replacement would then be made possible when the pericardial leaflets began to calcify. Novel aspects of the design added value to the science of heart valve replacements, through the use of sintered chrome cobalt in the valve components, the insights gained into mechanical testing of pericardium, and the patient benefits offered by the complete design. Further work is planned to fatigue test the assembly, undergo animal trials and make the valve available for commercial use.

  6. 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.

  7. Anticoagulation management in patients with mechanical heart valves having pacemaker or defibrillator insertion.

    Science.gov (United States)

    Schulman, S; Schoenberg, J; Divakara Menon, S; Spyropoulos, A C; Healey, J S; Eikelboom, J W

    2013-04-01

    In patients with a high risk for stroke and having invasive procedures with a high risk for bleeding it is unclear how anticoagulant therapy should be managed. We reviewed data from all patients with mechanical heart valves, who had elective insertion or replacement of pacemaker or implantable cardioverter defibrillator (ICD) during the past 8years at our hospital. Data on anticoagulant treatment, pocket hematoma and thromboembolic complications were captured. Of the 111 patients reviewed, 68 (61%) had a mechanical valve in the mitral position with or without other valves replaced and 43 (39%) had a mechanical valve only in the aortic position. Fifty-nine (53%) were undergoing replacement for their device. Six patients received a tapered warfarin regimen and 102 received preoperative bridging anticoagulation of whom 12 also received postoperative bridging. One stroke occurred 40days after pacemaker replacement in a patient with mitral mechanical valve and without postoperative bridging. Six patients (5.5%) developed pocket hematoma without a significant association to postoperative bridging, type of mechanical valve or to type of device. Predictors for pocket hematoma appeared to be replacement surgery (odds ratio 12.5; 95% confidence interval [CI], 0.69-228) and an international normalized ratio of 1.5 or higher on the day of surgery (odds ratio 8.4; 95% CI, 0.96-68.1). We found a low risk for stroke in the absence of postoperative bridging. For patients with device replacement surgery reversal of the anticoagulant effect at the time of procedure might reduce the risk for pocket hematoma, but this requires prospective evaluation including the risk of thromboembolism. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Evaluation of a transient, simultaneous, arbitrary Lagrange-Euler based multi-physics method for simulating the mitral heart valve.

    Science.gov (United States)

    Espino, Daniel M; Shepherd, Duncan E T; Hukins, David W L

    2014-01-01

    A transient multi-physics model of the mitral heart valve has been developed, which allows simultaneous calculation of fluid flow and structural deformation. A recently developed contact method has been applied to enable simulation of systole (the stage when blood pressure is elevated within the heart to pump blood to the body). The geometry was simplified to represent the mitral valve within the heart walls in two dimensions. Only the mitral valve undergoes deformation. A moving arbitrary Lagrange-Euler mesh is used to allow true fluid-structure interaction (FSI). The FSI model requires blood flow to induce valve closure by inducing strains in the region of 10-20%. Model predictions were found to be consistent with existing literature and will undergo further development.

  9. 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

  10. Pregnancy Outcome in Women with Mechanical Prosthetic Heart Valves Treated with Unfractionated Heparin (UFH) or Enoxaparin.

    Science.gov (United States)

    Khader, Khalid Abd Aziz Mohamad; Saad, Ahmed Samy; Abdelshafy, Mohammed

    2016-10-01

    This study was carried out to determine the maternal (including thromboembolic and hemorrhagic complications) and fetal outcomes (including miscarriage, stillbirth, baby death, and live birth) in women with mechanical heart valves managed with therapeutic doses of unfractionated heparin (UFH) versus enoxaparin during pregnancy. This is a prospective comparative, nonrandomized study. Pregnant women with mechanical heart valves presenting to high-risk pregnancy unit of Benha University Hospital, Egypt were treated with UFH 15,000 U/12 h versus enoxaparin (Clexane) 1 mg/kg SC/12 h during pregnancy and the results were analyzed. 40 pregnant women were included in the study. In 20 pregnant women, anticoagulation was with UFH, and 20 pregnant women received enoxaparin. One (3 %) thrombotic complication occurred with enoxaparin treatment. Noncompliance or subtherapeutic levels contributed to this outcome in this case. Antenatal hemorrhage occurred in 4 (10 %) and postpartum hemorrhagic complications in 5 (12.5 %) pregnancies. Of the 32 pregnant women who continued after 20 weeks' gestation, 100 % (17/17) of the women taking predominantly UFH had a surviving infant compared with 93 % (14/15) of the women taking primarily enoxaparin (p = 0.25). One intrauterine fetal death occurred in the enoxaparin group. There was no significant difference in the live birth rates between the two groups (p = 0.31). Compliance with therapeutic dose of UFH during pregnancy in women with mechanical heart valves is associated with a low risk of valve thrombosis and good fetal outcomes, but meticulous monitoring is essential.

  11. 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.

  12. Heart valve cryopreservation: protocol for addition of dimethyl sulphoxide and amelioration of putative amphotericin B toxicity.

    Science.gov (United States)

    Birtsas, Vassilios; Armitage, W John

    2005-04-01

    To investigate the need for stepwise addition of dimethyl sulphoxide to heart valves and amelioration of putative amphotericin B toxicity. There were four groups: an untreated control (Group 1) and three experimental groups. For the latter, porcine heart valves were exposed to the antibiotic/antimycotic mixture used for disinfecting heart valves in the Bristol Heart Valve Bank, for 24 h at 22 degrees C. Dimethyl sulphoxide (Me2SO, 10% v/v) was added either in two steps (5% then 10%) (Group 2) or in a single step. For single-step addition, valves were either first placed in Hanks' balanced salt solution for 10 min before transfer to the cryoprotectant solution (Group 3) or immersed directly in the 10% cryoprotectant solution (Group 4). The valve leaflets were dissected from the valves and frozen in 10% Me2SO in multi-well tissue culture plates at 1 degrees C/min to -80 degrees C. After storage overnight, the valve leaflets were warmed at approximately 11 degrees C/min and the cryoprotectant was removed by single-step dilution in excess Hartmann's solution. Each leaflet was then divided into four pieces, which were placed in separate wells of a culture plate. Outgrowth of cells from the explants was monitored daily and graded according to the extent of cell growth. After freezing and thawing, only 77% of the explants from valves placed directly into 10% Me2SO (Group 4) showed outgrowth of cells after freezing compared with 89% with two-step addition of Me2SO (Group 2) and 95% with one-step addition after the extra rinse in Hanks' solution (Group 3) (chi2, p=0.001). 92% of unfrozen control explants showed outgrowth of cells (Group 1). Only 37% of Group 4 explants reached confluence compared with 63 and 56%, respectively, of Groups 2 and 3 explants (chi2, p=0.007). The rates of cell growth in Group 2 (two-step addition of Me2SO) and Group 3 (one-step addition of Me2SO with additional Hanks' solution rinse) were similar and faster than the Group 4 (one-step addition of

  13. FLOW DYNAMIC COMPARISON BETWEEN RECESSED HINGE AND OPEN PIVOT BI-LEAFLET HEART VALVE DESIGNS.

    Science.gov (United States)

    Govindarajan, V; Udaykumar, H S; Chandran, K B

    2009-06-01

    The flow dynamics through the peripheral and hinge regions of a bi-leaflet mechanical heart valve are complex and result in abnormally high shear stresses particularly during the closing phase of the valve function. It has been observed that, the late stages of closure is more significant in the dynamics of platelet activation; therefore, the later stages of closure is simulated by solving the two-dimensional Navier-Stokes equations using an Eulerian Levelset based sharp interface Cartesian grid method. Using a fixed Cartesian mesh incorporating local mesh refinement for solution accuracy and efficiency, the flow through and within a recessed hinge design and an open pivot hinge design is compared. Platelets are modelled as point particles by Lagrangian particle tracking algorithm with one way coupling. A dilute particle flow is assumed and particle-particle interactions are neglected. It was observed that the hinge region of the open pivot valve indicated a lower potential for activation of platelets compared to that in valves with a recessed hinge design.

  14. Deformation of a membrane in a pulsatile flow: implications in heart valve design

    Science.gov (United States)

    Hernandez, C.; Guzman, J. E. V.; Zenit, R.

    2011-11-01

    Current designs of heart valves prosthetics have serious disadvantages and health issues for patients who use them. For this reason, a new design that combines durability (mechanical valves) and biocompatibility (biological valves) has to be conceived. Natural valves have very complex geometry because their leaflets have two principal curvatures, one imposed by the holding ring and a second one imposed by the bending of the closing arrangement. The objective of this research is to study the effects of both curvatures on the performance of a leaflet. It is well known that the increase of the curvature results in a larger stiffness, which, in turn, reduces the deflection of a leaflet. We conducted a study to determine the effect of changing the curvature (in two directions) of a flexible membrane when exposed to a steady and pulsatile flows. A study of the flow field that results from this interaction is also conducted by PIV measurements. Preliminary results of the leaflet deflection for many stiffnesses, curvatures and flow conditions will be presented and discussed.

  15. 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.

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

    Science.gov (United States)

    Silaschi, Miriam; Treede, Hendrik; Rastan, Ardawan J; Baumbach, Hardy; Beyersdorf, Friedhelm; Kappert, Utz; Eichinger, Walter; Rüter, Florian; de Kroon, Thomas L; Lange, Rüdiger; Ensminger, Stephan; Wendler, Olaf

    2016-11-01

    Transcatheter aortic valve replacement (TAVR) is an established therapy for patients with aortic stenosis (AS) at high surgical risk. The JenaValve™ is a second-generation, self-expanding transcatheter heart valve (THV), implanted through transapical access (TA). During stent deployment, a specific 'clipping-mechanism' engages native aortic valve cusps for fixation. We present 1-year outcomes of the JUPITER registry, a post-market registry of the JenaValve for TA-TAVR. The JUPITER registry is a prospective, multicentre, uncontrolled and observational European study to evaluate the long-term safety and effectiveness of the Conformité Européenne-marked JenaValve THV. A total of 180 patients with AS were enrolled between 2012 and 2014. End-points were adjudicated in accordance with the valve academic research consortium document no. 1 definitions. The mean age was 80.4 ± 5.9 years and the mean logistic European system for cardiac operative risk evaluation I 21.2 ± 14.7%. The procedure was successful in 95.0% (171/180), implantation of a second THV (valve-in-valve) was performed in 2.2% (4/180) and conversion to surgical aortic valve replacement (SAVR) was necessary in 2.8% (5/180). No annular rupture or coronary ostia obstruction occurred. Two patients required SAVR after the day of index procedure (1.1%). All-cause mortality at 30 days was 11.1% (20/180), being cardiovascular in 7.2% (13/180). A major stroke occurred in 1.1% (2/180) at 30 days, no additional major strokes were observed during 1 year. All-cause mortality after 30 days was 13.1% (21/160) and combined efficacy at 1 year was 80.8% (122/151). At 1-year follow-up, no patient presented with more than moderate paravalvular leakage, while 2 patients (3.2%) showed moderate, 12 (19.0%) mild and 49 (82.4%) trace/none paravalvular regurgitation. In a high-risk cohort of patients undergoing TA-TAVR for AS, the use of the JenaValve THV is safe and effective. In patients at higher risk for coronary ostia

  17. PREDICTION OF BLOOD FLOW VELOCITY AND LEAFLET DEFORMATION VIA 2D MITRAL VALVE MODEL

    Directory of Open Access Journals (Sweden)

    M.A.H. Mohd Adib

    2012-06-01

    Full Text Available In the mitral valve, regional variations in structure and material properties combine to affect the biomechanics of the entire valve. From previous studies, we know that the mitral valve leaflet tissue is highly extensible. A two-dimensional model of the mitral valve was generated using an Arbitrary Lagrangian-Eulerian (ALE mesh. A simple approximation of the heart geometry was used and the valve dimensions were based on actual measurements made. Valve opening and closure was simulated using contact equations. The objective of this study was to investigate and predict flow and leaflet phenomena via a simple 2D mitral valve model based on the critical parameter of blood. Two stages of mitral valves analysis were investigated: the systolic and diastolic stages. The results show a linear correlation between the mitral valve leaflet rigidity and the volume of backflow. Additionally, the simulation predicted mitral valve leaflet displacement during closure, which agreed with the results of our previous data analysis and the results for blood flow velocity during systole condition through the mitral valve outlet, as reported in the medical literature. In conclusion, these computational techniques are very useful in the study of both degenerative valve disease and failure of prostheses and will be further developed to investigate heart valve failure and subsequent surgical repair.

  18. Successful matrix guided tissue regeneration of decellularized pulmonary heart valve allografts in elderly sheep.

    Science.gov (United States)

    Theodoridis, Karolina; Tudorache, Igor; Calistru, Alexandru; Cebotari, Serghei; Meyer, Tanja; Sarikouch, Samir; Bara, Christoph; Brehm, Ralph; Haverich, Axel; Hilfiker, Andres

    2015-06-01

    In vivo repopulation of decellularized allografts with recipient cells leads to a positive remodeling of the graft matrix in juvenile sheep. In light of the increasing number of heart valve replacements among older patients (>65 years), this study focused on the potential for matrix-guided tissue regeneration in elderly sheep. Pulmonary valve replacement was performed in seven-year old sheep using decellularized (DV), decellularized and CCN1-coated (RV), or decellularized and in vitro reendothelialized pulmonary allografts (REV) (n=6, each group). CCN1 coating was applied to support re-endothelialization. In vitro re-endothelialization was conducted with endothelial-like cells derived from peripheral blood. Echocardiograms of all grafts showed adequate graft function after implantation and at explantation 3 or 6 months later. All explants were macroscopically free of thrombi at explantation, and revealed repopulation of the allografts on the adventitial side of valvular walls and proximal in the cusps. Engrafted cells expressed vimentin, sm α-actin, and myosin heavy chain 2, while luminal cell lining was positive for vWF and eNOS. Cellular repopulation of valvular matrix demonstrates the capacity for matrix-guided regeneration even in elderly sheep but is not improved by in vitro endothelialization, confirming the suitability of decellularized matrix for heart valve replacement in older individuals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. 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 surgery, and intraoperative blood transfusion >3000 ml as predictors of in-hospital death. Multivariate logistic regression analysis confirmed low serum albumin surgery should be considered for operative risk estimation, and adequate preoperative nutrition management may improve surgical outcomes for hemodialysis-dependent patients.

  20. Proteomic analysis of mitral valve in Lewis rat with acute rheumatic heart disease.

    Science.gov (United States)

    Li, Wenting; Zeng, Zhiyu; Gui, Chun; Zheng, Huilei; Huang, Weiqiang; Wei, Heng; Gong, Danping

    2015-01-01

    Rheumatic heart disease (RHD) makes a heavy burden in human lives and economy. The proteomic analysis of acute rheumatic heart disease (ARHD) can provide precious data to study RHD at the early stages, but no one has looked into. So based on our early research we applied the method of continuous GAS stimulation on Lewis rats to duplicate the animal model of ARHD. And the mitral valves of rats in control group (n=10) and ARHD group (n=10) were selected for proteomic analysis of ARHD with the iTRAQ labeling based 2D LC-ESI-MS/MS quantitative technology. We identified 3931 proteins in valve tissue out of which we obtained 395 differentially expressed proteins containing 176 up-regulated proteins and 119 down-regulated proteins. Changes in levels of GAPDH (6.793 times higher than the control group) and CD9 (2.63 times higher than the control group) were confirmed by Western blot or immunohistochemistry. The differentially expressed proteins such as GAPDH, CD9, myosin, collagen and RAC1 may be potential biomarkers for ARHD. Moreover, the mitral valve protein profile shed light on further understanding and investigating ARHD.

  1. 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.

  2. 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.

  3. The role of the sewing ring in tissue healing: a pathologic study of explanted mechanical heart valves.

    Science.gov (United States)

    Kurian, Mathew V; Sabareeswaran, Arumugam; Kanchanamala, Muniraj; Balachandran, Seetharaman; Mogileswari, Dhananjayan; Subban, Vijayakumar

    2012-03-01

    Serious complications may occur after heart valve replacement, and many such patients will require reoperation. The study aim was to identify the pattern of tissue response around the sewing ring of those valves that have been explanted as a result of various valve-associated complications. A total of 51 mechanical heart valves (MHVs) was explanted from 45 patients who had undergone reoperation for valve-related complications. The examination of the valves included an analysis of the operative findings, macroscopic findings, histopathology, and dissection of the sewing ring. The extent of tissue hyperplasia was variable around the sewing rings of valves explanted for various pathologies. In pannus, the hyperplastic tissue extended into the valve orifice and produced an obstruction to flow, whereas in thrombosed valves the thrombus was attached to the tissue at the annulus. In non-infective pathologies, the histology revealed cellular infiltration that was limited to the peripheral fabric layers of the sewing ring, though the extent of infiltration was not increased with the duration of implantation. In prosthetic valve endocarditis (PVE), the surrounding hyperplastic tissue was granulomatous, but cellular infiltration into the sewing ring was absent. The dissection of various models of explanted valves revealed that different types of filler and fixing mechanisms had increased the bulk of the sewing ring. Tissue hyperplasia of varying extent occurs around the sewing ring after MHV implantation. The cellular elements grow into the peripheral layers, but not the deeper layers, of the sewing ring. In PVE, there was an absence of cellular infiltration into the sewing ring.

  4. Subclinical leaflet thickening and stent frame geometry in self-expanding transcatheter heart valves

    DEFF Research Database (Denmark)

    Fuchs, Andreas; De Backer, Ole; Brooks, Matthew

    2017-01-01

    AIMS: This study aimed to assess the potential relationship between subclinical leaflet thickening and stent frame geometry in patients who underwent aortic valve replacement with a self-expanding transcatheter heart valve (THV). METHODS AND RESULTS: Seventy-five patients with a self-expanding THV...... were studied with 4D-computed tomography and analysed for leaflet thickening. There was no difference in THV size, overall THV expansion, eccentricity or implantation depth between patients with and those without leaflet thickening. Moderate-to-severe regional THV underexpansion (≤90°) more frequently...... occurred at the non-coronary and right coronary cusps with a significantly higher incidence of leaflet thickening than in cases of full regional THV expansion (24% vs. 3%, p

  5. Fluid structure interaction (FSI) simulation of a bileaflet mechanical heart valve (MHV)

    Science.gov (United States)

    Ge, Liang; Bor, Iman; Dasi, Lakshmi; Sotiropoulos, Fotis; Yoganathan, Ajit

    2006-11-01

    MHVs are widely used as prosthetics for dysfunctional heart valves. All current MHV designs, however, are prone to thrombus formation, which is believed to be strongly associated with the non-physiological hemodynamics patterns and elevated shear stress level induced by the valve; it is, therefore, of enormous practical importance to study the hemodynamics through MHVs. Here we present an FSI solver modeling the physiological MHV hemodynamics. The solver uses a strong coupling scheme for the FSI problem and a recently developed curvilinear grid/immersed boundary method for flow simulation. The FSI solver is applied to model an in-vitro MHV hemodynamics measurement. The experimental pulsatile flow waveform with peak Reynolds number of 4000 is specified at the inlet and the flow is modeled by DNS. The results, including the dynamics of wake vortical structure, shear distribution and leaflet kinematics, are validated against the experimental data.

  6. Pregnancy Outcome with Intracytoplasmic Sperm Injection Method in a Woman with Prosthetic Heart Valves

    Directory of Open Access Journals (Sweden)

    Fahimeh Kashfi

    2007-01-01

    Full Text Available There is an increased risk of thromboembolism, anticoagulant-related hemorrhage, fetal-wastage and congestive cardiac failure in pregnant women with mechanical heart valves. In order to have a good outcome, the care of such patients must necessarily be multidisciplinary and in a well- equipped centre with adequate support services .One such patient who had mechanical mitral and aortic valves replacement in 2000 receiving warfarin anticoagulant therapy, presented with a first trimester pregnancy by ICSI method in 2006. She remained in stable homodynamic state and went through pregnancy without event. Delivery was done by caesarian section at 37 weeks gestation age.With considering use of warfarin during pregnancy, use of stimulation protocol during ICSI and delivering normal neonate ultimately, this interesting case is presented herein.

  7. 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.

  8. Reverse remodeling of left heart following mitral valve repair in case of mesenchimal dysplasia

    Directory of Open Access Journals (Sweden)

    А. М. Караськов

    2015-10-01

    Full Text Available Objectives. Volume overload in mitral regurgitation leads to compensatory dilation of the left heart chambers. Surgical correction promotes reverse remodeling of the heart. In this study, focus was placed on the changes in the left heart resulted from mitral regurgitation correction by using two different surgical techniques for mitral valve repair. Methods. 94 patients with posterior mitral valve prolapse were randomized in two groups. The first group patients underwent artificial chordal replacement, while a leaflet resection technique was used for the patients of the second group. Preoperative transthoracic and intraoperative transesophageal echocardiography was performed for all patients and data were obtained at 10-12 days after surgery and during long-term follow up. Results. In the early postoperative period, significant reverse remodeling of the left heart chambers was observed (LA 5.4-4.6, p <0.05; LVEDD 5.8-4.9 p <0.05; LVESD 3.6 - 3.1 p <0.05 - LA 5.2 - 4.5 p <0.05; LVEDD 5.8 - 4.8 p <0.05; LVESD 3.5 - 3.2 p <0.05. The mitral valve orifice area in the groups was 3.3 - 3.3 - 3.2 when replacing chords and 3.5 - 3.4 - 3.2 when doing resection, with p being equal to 0.32, 0.36 and 0.51 respectively. The mean diastolic gradient in the first group was 2.0 - 3.0 - 3.0 mm Hg, while in the second one it amounted to 2.3 - 3.2 - 3.3 mmHg, with p <0.05. Conclusion. The authors conclude that significant remodeling of the left heart occurs in the early postoperative period. In the immediate postoperative period, the mitral valve area tends to decrease and the gradient has a tendency to increase in both groups, with no significant changes observed in the late postoperative period.

  9. Mitral valve regurgitation

    Science.gov (United States)

    ... around the valve. You are at risk for mitral valve regurgitation if you have: Coronary heart disease and high blood pressure Infection of the heart valves Mitral valve prolapse (MVP) Rare conditions, such as untreated syphilis or Marfan ... heart disease. This is a complication of untreated strep throat ...

  10. Effects of tolvaptan in the early postoperative stage after heart valve surgery: results of the STAR (Study of Tolvaptan for fluid retention AfteR valve surgery) trial.

    Science.gov (United States)

    Nishi, Hiroyuki; Toda, Koichi; Miyagawa, Shigeru; Yoshikawa, Yasushi; Fukushima, Satsuki; Kawamura, Masashi; Yoshioka, Daisuke; Saito, Tetsuya; Ueno, Takayoshi; Kuratani, Toru; Sawa, Yoshiki

    2015-12-01

    The purpose of this study was to assess the efficacy of tolvaptan, a vasopressin V2 receptor antagonist, for the management of postoperative surgical fluid retention after heart valve surgery. This was a prospective observational study of 64 patients with heart valve disease who underwent valve surgery between 2013 and 2014. Those in the tolvaptan group received tolvaptan in addition to conventional diuretic therapy. The results were compared to the results of 55 patients who underwent heart valve surgery between 2007 and 2010 and received conventional postoperative diuretics alone. The time to return to the preoperative BW was significantly shorter in the patients who received tolvaptan (6.1 ± 3.8 vs. 8.7 ± 6.7 days, p tolvaptan group. The response to tolvaptan was related to the postoperative degree of BW increase and the preoperative creatinine level. Tolvaptan was effective in treating fluid retention during the early postoperative stage in cardiac surgery patients, without increased renal failure or abnormal electrolyte levels. This new type of diuretic therapy may be a suitable option for postoperative fluid management in patients undergoing cardiac surgery.

  11. Hypoxic encephalopathy after heart valve replacement: etiology and pathogenesis, diagnostic criteria and treatment

    Directory of Open Access Journals (Sweden)

    В. Г. Постнов

    2015-10-01

    Full Text Available Reviewed in this paper are modern approaches in the intensive therapy of acute hypoxic encephalopathy developing in a number of occasions after the heart valve replacement surgery. The study is based on the results of neurological, neuropsychological and neurophysiological (EEG examinations of 240 patients who underwent heart valve replacement surgery under cardiopulmonary bypass conditions complicated later by the development of hypoxic encephalopathies of varying severity and who received complex intensive care. Relying on many years of experience in the treatment of heart surgery patients in whom manifestations of encephalopathy developed in the early postoperative period, or were delayed, we have formulated the following algorithms of therapy. (1 Maintenance of normal blood gas: Hb>100 g/L, pH 7.45, PaCO2 35 mmHg. (2 Maintenance of hemodynamics: ABPsystolic>90 mmHg. (3 Supplying fluids and electrolytes: isoosmolar infusion solutions, adding of KCl and MgSO4 to the infusion. (4 Antiedemic therapy: 15% mannitol or 40% glycerol solution. (5 If necessary (in case of psychomotor agitation, seizures, short-acting barbiturates (sodium thiopental, neuroleptics (haloperidol, propofol. No benzodiazepines in case of psychoses (6 Cerebral metabolism stimulation (not earlier than 48 hours after surgery with cholinomimetics, nootropics, cerebral blood flow protectors. Cholinomimetics are allowed on the first day after surgery. This algorithm and the above-mentioned groups of drugs, especially central cholinomimetics, allow for correcting the neurocognitive impairment in the discussed group of patients quickly and effectively.

  12. Inflammatory response assessment of a hybrid tissue-engineered heart valve leaflet.

    Science.gov (United States)

    Alavi, S Hamed; Liu, Wendy F; Kheradvar, Arash

    2013-02-01

    Despite substantial research in the past few decades, only slight progress has been made toward developing biocompatible, tissue-engineered scaffolds for heart valve leaflets that can withstand the dynamic pressure inside the heart. Recent progress on the development of hybrid scaffolds, which are composed of a thin metal mesh enclosed by multi-layered tissue, appear to be promising for heart valve engineering. This approach retains all the advantages of biological scaffolds while developing a strong extracellular matrix backbone to withstand dynamic loading. This study aims to test the inflammatory response of hybrid tissue-engineered leaflets based on characterizing the activation of macrophage cells cultured on the surfaces of the tissue construct. The results indicate that integration of biological layers around a metal mesh core-regardless of its type-may reduce the evoked inflammatory responses by THP-1 monocyte-like cells. This observation implies that masking a metal implant within a tissue construct prior to implantation can hide it from the immune system and may improve the implant's biocompatibility.

  13. Gal knockout pig pericardium: new source of material for heart valve bioprostheses.

    Science.gov (United States)

    Lila, Nermine; McGregor, Christopher G A; Carpentier, Sophie; Rancic, Jeanne; Byrne, Guerard W; Carpentier, Alain

    2010-05-01

    Although glutaraldehyde fixation is known to reduce immunogenicity and degeneration of heart valve bioprostheses, some degree of immunogenicity persists, which may trigger calcification. The aims of this study were to: (1) define the role of alpha-1,3-galactosyltransferase (alpha-Gal) antigen in valve calcification by comparing alpha-Gal-positive and alpha-Gal-deficient (GT-KO) pig pericardium; and (2) elucidate the role of human anti-Gal antibodies in the process of calcification and to determine the potential influence of different tissue-fixation techniques. Glutaraldehyde-treated pericardium from alpha-Gal-positive and GT-KO pigs, with or without pre-labeling with human anti-Gal antibodies, were implanted in rats during 1 month. In glutaraldehyde-fixed pericardium, calcification levels were significantly lower in GT-KO pig pericardium (132.8 +/- 5.8 microg/mg) as compared with alpha-Gal-positive pig pericardium (155.7 +/- 7.1 microg/mg) (p pig pericardium followed by a mix of formaldehyde, ethanol and Tween 80 (FET), the calcification levels were lower in GT-KO pig pericardium (0.35 +/- 0.1 microg/mg) as compared with alpha-Gal-positive pig pericardium (4.6 +/- 4.2 microg/mg). In glutaraldehyde-fixed pig pericardium + FET pre-incubated with human anti-Gal antibodies, calcification levels were significantly greater in alpha-Gal-positive pig pericardium (43.8 +/- 8.5 microg/mg) as compared with GT-KO pig pericardium (5.7 +/- 2.9 microg/mg) (p pig pericardium could be beneficial as a new source of material for heart valve bioprostheses. Copyright (c) 2010 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  14. [Open heart tricuspid valve replacement in a heroin addict Anaesthesiological management].

    Science.gov (United States)

    Kozian, A; Schilling, T; Tiede, T; Huth, C; Hachenberg, T

    2005-06-01

    A 24-year-old female with a history of former heroin addiction underwent open heart surgery for a mechanical tricuspid valve replacement. Anaesthesiological management included a thoracic epidural catheter at the Th(2)/Th(3) segments and balanced general anaesthesia (remifentanil, desflurane/propofol). Additionally, clonidine (2 microg*kg(-1)*h(-1)) was continuously administered. Pain therapy was achieved using 0.375% ropivacaine via a thoracic epidural catheter (4 ml*h(-1)) and metamizole (4 x 1 g/day) intravenously. With this concept we were able to achieve an appropriate anaesthesia and analgesia and the operation was carried out without complications.

  15. Absence of the aortic valve associated with hypoplastic left-sided heart syndrome

    Directory of Open Access Journals (Sweden)

    Atik Edmar

    2000-01-01

    Full Text Available In this report we describe the twelveth case in the literature of absence of the aortic valve cusps, associated with hypoplastic left-sided heart syndrome in a neonate. Clinical and hemodynamic conditions in our patient resemble the classical features of this syndrome except for a greater development of the ascending aorta and the left ventricular cavity, due to aortic insufficiency. A patch was unsuccessfully inserted at the aortic annulus to exclude the left ventricle from the circulation. In addition the Norwood operation was performed.

  16. Exercise-based cardiac rehabilitation for adults after Heart valve surgery (protocol)

    DEFF Research Database (Denmark)

    Lærum Sibilitz, Kristine; Berg, Selina Kikkenborg; Tang, Lars Hermann

    2013-01-01

    This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the benefits and harms of exercise-based intervention programmes (exercise-based interventions alone or in combination with psycho-educational components), compared to no intervention, or treatmen...... as usual, in adults who have had heart valve surgery. In this review we will focus on programmes that include an exercise-based intervention with, or without, another rehabilitation component (such as a psycho-educational component)....

  17. Review of numerical methods for simulation of mechanical heart valves and the potential for blood clotting.

    Science.gov (United States)

    Zakaria, Mohamad Shukri; Ismail, Farzad; Tamagawa, Masaaki; Aziz, Ahmad Fazli Abdul; Wiriadidjaja, Surjatin; Basri, Adi Azrif; Ahmad, Kamarul Arifin

    2017-09-01

    Even though the mechanical heart valve (MHV) has been used routinely in clinical practice for over 60 years, the occurrence of serious complications such as blood clotting remains to be elucidated. This paper reviews the progress that has been made over the years in terms of numerical simulation method and the contribution of abnormal flow toward blood clotting from MHVs in the aortic position. It is believed that this review would likely be of interest to some readers in various disciplines, such as engineers, scientists, mathematicians and surgeons, to understand the phenomenon of blood clotting in MHVs through computational fluid dynamics.

  18. Outcomes of mechanical valves in the pulmonic position in patients with congenital heart disease over a 20-year period.

    Science.gov (United States)

    Shin, Hong Ju; Kim, Young-Hwue; Ko, Jae-Kon; Park, In-Sook; Seo, Dong Man

    2013-04-01

    Homografts or bioprosthetic valves have been preferred in the pulmonic position in patients with congenital heart disease. However, unsatisfactory long-term results have aroused interest in the use of mechanical valves. In this study, we investigated the long-term outcomes of mechanical valves implanted in the pulmonic position. The medical records of 37 patients (27 male, 73%) who underwent 38 mechanical pulmonary valve replacements between October 1988 and February 2011 were reviewed, retrospectively. The median age of patients was 13.5 years (range, 7 months to 23 years), and the median number of prior operations per patient was 2 (range, 0 to 5). Tetralogy of Fallot was the most common diagnosis (n=23). The median valve size was 23 mm (range, 17 to 27 mm), and the median follow-up duration after pulmonary valve replacement was 24.6 months (range, 1.3 months to 22.5 years). Events were defined as the following: valve failure, thrombosis, embolism, bleeding, reoperation, and death. There was no in-hospital mortality, but there were 2 late deaths (1 heart failure and 1 traffic accident at 10.8 months and 8.7 years postoperatively, respectively). Excluding the traffic accident death, survival rates were 97%, 97%, and 97%, at 1, 5, and 10 years, respectively. Freedom from thromboembolism or bleeding events was 92%, 92%, and 78.8%, at 1, 5 and 10 years, respectively. Two reoperations were performed at 6.8 and 10.2 years postoperatively. Freedom from reoperation was 100%, 100%, and 85.7%, at 1, 5, and 10 years, respectively. Durability of mechanical valve in pulmonic position was excellent. Thromboembolism or bleeding events due to anticoagulation therapy were rare. In growing patients who have undergone prior sternotomies requiring a pulmonary valve replacement, a mechanical valve could be an attractive option. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  19. Transcatheter Heart Valve Selection and Permanent Pacemaker Implantation in Patients With Pre-Existent Right Bundle Branch Block.

    Science.gov (United States)

    van Gils, Lennart; Tchetche, Didier; Lhermusier, Thibault; Abawi, Masieh; Dumonteil, Nicolas; Rodriguez Olivares, Ramón; Molina-Martin de Nicolas, Javier; Stella, Pieter R; Carrié, Didier; De Jaegere, Peter P; Van Mieghem, Nicolas M

    2017-03-03

    Right bundle branch block is an established predictor for new conduction disturbances and need for a permanent pacemaker (PPM) after transcatheter aortic valve replacement. The aim of the study was to evaluate the absolute rates of transcatheter aortic valve replacement related PPM implantations in patients with pre-existent right bundle branch block and categorize for different transcatheter heart valves. We pooled data on 306 transcatheter aortic valve replacement patients from 4 high-volume centers in Europe and selected those with right bundle branch block at baseline without a previously implanted PPM. Logistic regression was used to evaluate whether PPM rate differed among transcatheter heart valves after adjustment for confounders. Mean age was 83±7 years and 63% were male. Median Society of Thoracic Surgeons score was 6.3 (interquartile range, 4.1-10.2). The following transcatheter valve designs were used: Medtronic CoreValve (n=130; Medtronic, Minneapolis, MN); Edwards Sapien XT (ES-XT; n=124) and Edwards Sapien 3 (ES-3; n=32; Edwards Lifesciences, Irvine, CA); and Boston Scientific Lotus (n=20; Boston Scientific Corporation, Marlborough, MA). Overall permanent pacemaker implantation rate post-transcatheter aortic valve replacement was 41%, and per valve design: 75% with Lotus, 46% with CoreValve, 32% with ES-XT, and 34% with ES-3. The indication for PPM implantation was total atrioventricular block in 98% of the cases. Lotus was associated with a higher PPM rate than all other valves. PPM rate did not differ between ES-XT and ES-3. Ventricular paced rhythm at 30-day and 1-year follow-up was present in 81% at 89%, respectively. Right bundle branch block at baseline is associated with a high incidence of PPM implantation for all transcatheter heart valves. PPM rate was highest for Lotus and lowest for ES-XT and ES-3. Pacemaker dependency remained high during follow-up. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by

  20. 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.

  1. Kodamaea ohmeri tricuspid valve endocarditis with right ventricular inflow obstruction in a neonate with structurally normal heart

    Directory of Open Access Journals (Sweden)

    Sundaram Ponnusamy

    2011-01-01

    Full Text Available The yeast Kodamaea (Pichia ohmeri is a rare human pathogen with infrequent report of neonatal infection. Native valve endocarditis by Kodamaea ohmeri is extremely rare. The current case report describes a case of fatal nosocomial native valve endocarditis without any structural heart defects in a 40dayold baby. The patient was referred to our institute after having ICU stay of 18 days in another hospital for necrotizing enterocolitis and was found to have obstructive tricuspid valve mass and fungemia with Kodamaea ohmeri. In spite of the treatment, patient developed sepsis with disseminated intravascular coagulation and could not be revived.

  2. A time-dependent numerical analysis of flow in a mechanical heart valve: Comparison with experimental results

    Science.gov (United States)

    Gkanis, Vasileios; Housiadas, Christos

    2010-06-01

    There is a great need to fabricate heart valves that have similar haemodynamic properties with the natural ones. Towards this goal, we examine the dynamics of fluid flow in a mechanical heart valve with one leaflet. The fluid is incompressible and Newtonian and the leaflet is a neo-Hookean material. The Arbitrary Lagrangian Eulerian method is used to model the fluid-leaflet interaction, and the system of equations is solved using the Finite Element method. The pseudo solid approach along with a set of algebraic equations are used to deform the mesh, while care is taken to avoid remeshing of the domain, at the moment of valve closure. The computational results are compared against the experimental results, and we find an excellent agreement for the time period of valve closure, the time the valve is fully opened, and the value of the maximum valve opening angle. This study indicates that the present model is capable of describing the valve dynamics in physiological geometries.

  3. Computational fluid dynamics study of a protruded-hinge bileaflet mechanical heart valve.

    Science.gov (United States)

    Wang, J; Yao, H; Lim, C J; Zhao, Y; Yeo, T J; Hwang, N H

    2001-03-01

    Following clinical experience with the Medtronic Parallel bileaflet mechanical heart valve, considerable interest has been shown in investigating fluid mechanics inside the hinge socket. Most of these studies involved hinges that are recessed into the valve housing, such as the St. Jude Medical (SJM), CarboMedics, Sorin and On-X bileaflet mechanical heart valves. The aim of this study was to investigate the flow fields of a protruded hinge under steady flow conditions, with the occluder in its fully open position. Computational fluid dynamics (CFD) simulation using the Fluent 4.4.7 commercial solver was applied in this investigation. This protruded hinge mechanism for pivoting the occluder is an in-house design from the Cardiovascular Dynamics Laboratory, Nanyang Technological University. The Fluent 4.4.7 code was run on a Silicon Graphic Inc. computer (4-CPUx185 MHz) in the CFD simulation. A body-fitted coordinates (BFC) grid was generated to cover the entire valvular flow domain, including the interior of the hinge and leaflet. Clearance between the leaflet and pivot housing was 50-70 microm. In the vicinity of the protruded hinge, mesh cells were small compared with hinge dimensions. A power law distribution of grid points was applied to optimize the number of cells used to cluster the entire flow field. The overall computational flow domain of the valve channel, including the floating leaflet and immersed hinge, was approximately 170,000 cells in total. Inside the hinge socket, approximately 10,000 cells were generated. A comparative model with recessed hinge that resembled the SJM valve hinge design was modeled. Due to geometric difficulties, an unstructured grid scheme was applied. Great attention was focused within the hinge pocket, in particular to the clearance between the hinge pivot and leaflet. A total of 2 million cells was generated for the whole computational flow domain. Under steady flow conditions, with the leaflet fixed in an open position, the

  4. A review of outcome following valve surgery for rheumatic heart disease in Australia.

    Science.gov (United States)

    Russell, E Anne; Tran, Lavinia; Baker, Robert A; Bennetts, Jayme S; Brown, Alex; Reid, Christopher M; Tam, Robert; Walsh, Warren F; Maguire, Graeme P

    2015-09-23

    Globally, rheumatic heart disease (RHD) remains an important cause of heart disease. In Australia it particularly affects younger Indigenous and older non-Indigenous Australians. Despite its impact there is limited understanding of the factors influencing outcome following surgery for RHD. The Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database was analysed to assess outcomes following surgical procedures for RHD and non-RHD valvular disease. The association with demographics, co-morbidities, pre-operative status, valve(s) affected and operative procedure was evaluated. Outcome of 1384 RHD and 15843 non-RHD valve procedures was analysed. RHD patients had longer ventilation, experienced fewer strokes and had more readmissions to hospital and anticoagulant complications. Mortality following RHD surgery at 30 days was 3.1% (95% CI 2.2 - 4.3), 5 years 15.3% (11.7 - 19.5) and 10 years 25.0% (10.7 - 44.9). Mortality following non-RHD surgery at 30 days was 4.3% (95% CI 3.9 - 4.6), 5 years 17.6% (16.4 - 18.9) and 10 years 39.4% (33.0 - 46.1). Factors independently associated with poorer longer term survival following RHD surgery included older age (OR1.03/additional year, 95% CI 1.01 - 1.05), concomitant diabetes (OR 1.7, 95% CI 1.1 - 2.5) and chronic kidney disease (1.9, 1.2 - 2.9), longer invasive ventilation time (OR 1.7 if greater than median value, 1.1- 2.9) and prolonged stay in hospital (1.02/additional day, 1.01 - 1.03). Survival in Indigenous Australians was comparable to that seen in non-Indigenous Australians. In a large prospective cohort study we have demonstrated survival following RHD valve surgery in Australia is comparable to earlier studies. Patients with diabetes and chronic kidney disease, were at particular risk of poorer long-term survival. Unlike earlier studies we did not find pre-existing atrial fibrillation, being an Indigenous Australian or the nature of the underlying valve lesion were independent

  5. Vorticity dynamics of a bileaflet mechanical heart valve in an axisymmetric aorta

    Science.gov (United States)

    Dasi, L. P.; Ge, L.; Simon, H. A.; Sotiropoulos, F.; Yoganathan, A. P.

    2007-06-01

    We present comprehensive particle image velocimetry measurements and direct numerical simulation (DNS) of physiological, pulsatile flow through a clinical quality bileaflet mechanical heart valve mounted in an idealized axisymmetric aorta geometry with a sudden expansion modeling the aortic sinus region. Instantaneous and ensemble-averaged velocity measurements as well as the associated statistics of leaflet kinematics are reported and analyzed in tandem to elucidate the structure of the velocity and vorticity fields of the ensuing flow-structure interaction. The measurements reveal that during the first half of the acceleration phase, the flow is laminar and repeatable from cycle to cycle. The valve housing shear layer rolls up into the sinus and begins to extract vorticity of opposite sign from the sinus wall. A start-up vortical structure is shed from the leaflets and is advected downstream as the leaflet shear layers become wavy and oscillatory. In the second half of flow acceleration the leaflet shear layers become unstable and break down into two von Karman-like vortex streets. The onset of vortex shedding from the valve leaflets is responsible for the growth of significant cycle-to-cycle vorticity oscillations. At peak flow, the housing and leaflet shear layers undergo secondary instabilities and break down rapidly into a chaotic, turbulent-like state with multiple small-scale vortical structures emerging in the flow. During the deceleration and closing phases all large-scale coherent flow features disappear and a chaotic small-scale vorticity field emerges, which persists even after the valve has closed. Probability density functions of the leaflet position during opening and closing phases show that the leaflet position fluctuates from cycle to cycle with larger fluctuations evident during valve closure. The DNS is carried out by prescribing the leaflet kinematics from the experimental data. The computed instantaneous vorticity fields are in very good

  6. Numerical analysis of the hemodynamic performance of bileaflet mechanical heart valves at different implantation angles.

    Science.gov (United States)

    Kuan, Yee Han; Nguyen, Vinh-Tan; Kabinejadian, Foad; Su, Boyang; Kim, Sangho; Yoganathan, Ajit P; Leo, Hwa Liang

    2014-09-01

    The effects of the implantation angle of bileaflet mechanical heart valves (BMHVs) on the sinus region and downstream flow profiles were investigated. Three-dimensional numerical simulations of BMHVs were performed under physiologic pulsatile flow conditions. The study aim was to examine how the flow fields of different aortic sinus shapes and the downstream aortic arch geometry would be affected by implantation angle. Two geometric models of sinus were investigated: a simplified axisymmetric sinus; and a three-sinus aortic root model, with two different downstream geometries, namely a straight pipe and a simplified curved aortic arch. A 29 mm St. Jude Medical BMHV geometric model was used and positioned at four different angles (0 degrees, 30 degrees, 60 degrees and 90 degrees). The simulation results showed variation in downstream flow profiles at different implantation angles. Generally, at position Z = 1D along the centerline (where Z refers to the axis normal to the x-y plane and D is the inlet diameter), the triple-jet structures were observed with a slight shift of the center jet for three-sinus aortic cases. Apparent differences were observed at position Z = 2D and 4D, such as higher velocity profiles at the inner arch wall. The flow field downstream of the valve implanted at 0 degrees (anatomic position) showed the smallest overall asymmetry at peak systole, while the flow field downstream of the valve implanted at 90 degrees (anti-anatomic position) exhibited high regions of recirculation. Valve orientation was found not to affect the shear stress distribution significantly in the downstream aorta, and this was in agreement with the findings of earlier studies.

  7. GuaragnaSCORE satisfactorily predicts outcomes in heart valve surgery in a Brazilian hospital.

    Science.gov (United States)

    Sá, Michel Pompeu Barros de Oliveira; Sá, Marcus Villander Barros de Oliveira; Albuquerque, Ana Carla Lopes de; Silva, Belisa Barreto Gomes da; Siqueira, José Williams Muniz de; Brito, Phabllo Rodrigo Santos de; Vasconcelos, Frederico Pires; Lima, Ricardo de Carvalho

    2012-01-01

    The aim of this study is to evaluate the applicability of GuaragnaSCORE for predicting mortality in patients undergoing heart valve surgery in the Division of Cardiovascular Surgery of Pronto Socorro Cardiológico de Pernambuco - PROCAPE, Recife, PE, Brazil. Retrospective study involving 491 consecutive patients operated between May/2007 and December/2010. The registers contained all the information used to calculate the score. The outcome of interest was death. Association of model factors with death (univariate analysis and multivariate logistic regression analysis), association of risk score classes with death and accuracy of the model by the area under the ROC (receiver operating characteristic) curve were calculated. The incidence of death was 15.1%. The nine variables of the score were predictive of perioperative death in both univariate and multivariate analysis. We observed that the higher the risk class of the patient (low, medium, high, very high, extremely high), the greater is the incidence of postoperative AF (0%; 7.2%; 25.5%; 38.5%; 52.4%), showing that the model seems to be a good predictor of risk of postoperative death, in a statistically significant association (P <0.001). The score presented a good accuracy, since the discrimination power of the model in this study according to the ROC curve was 78.1%. The Brazilian score proved to be a simple and objective index, revealing a satisfactory predictor of perioperative mortality in patients undergoing heart valve surgery at our institution.

  8. Predicting risk of atrial fibrillation after heart valve surgery: evaluation of a Brazilian risk score.

    Science.gov (United States)

    Sá, Michel Pompeu Barros de Oliveira; Sá, Marcus Villander Barros de Oliveira; Albuquerque, Ana Carla Lopes de; Silva, Belisa Barreto Gomes da; Siqueira, José Williams Muniz de; Brito, Phabllo Rodrigo Santos de; Ferraz, Paulo Ernando; Lima, Ricardo de Carvalho

    2012-01-01

    The aim of this study is to evaluate the applicability of a Brazilian score for predicting atrial fibrillation (AF) in patients undergoing heart valve surgery in the Division of Cardiovascular Surgery of Pronto Socorro Cardiológico de Pernambuco - PROCAPE (Recife, PE, Brazil). Retrospective study involving 491 consecutive patients operated between May/2007 and December/2010. The registers contained all the information used to calculate the score. The outcome of interest was AF. We calculated association of model factors with AF (univariate analysis and multivariate logistic regression analysis), and association of risk score classes with AF. The incidence of AF was 31.2%. In multivariate analysis, the four variables of the score were predictors of postoperative AF: age >70 years (OR 6.82; 95%CI 3.34-14.10; P 1500 ml at first 24 hours (OR 1.92; 95%CI 1.28-2.88; P=0.002). We observed that the higher the risk class of the patient (low, medium, high, very high), the greater is the incidence of postoperative AF (4.2%; 18.1%; 30.8%; 49.2%), showing that the model seems to be a good predictor of risk of postoperative AF, in a statistically significant association (P<0.001). The Brazilian score proved to be a simple and objective index, revealing a satisfactory predictor of development of postoperative AF in patients undergoing heart valve surgery at our institution.

  9. Comparison of platelet activation through hinge vs bulk flow in mechanical heart valves

    Science.gov (United States)

    Hedayat, Mohammadali; Borazjani, Iman

    2017-11-01

    Bileaflet mechanical heart valves increase the risk of thrombus formation in patients which is believed to be initiated by platelet activation. Platelets can be activated by the elevated shear stresses in the bulk flow during the systole phase or the flow through the hinge during the diastole. However, the importance of platelet activation by the bulk flow vs the hinge in MHVs has yet to be studied. Here, we investigate the contribution of each of the above mechanisms to the activation of platelets in MHs by performing simulation of the flow through a 25mm St. Jude Medical valve placed in a straight aorta. Two different gap sizes (250 and 150 micrometer) are used in this study. The simulations are done using a sharp interface curvilinear immersed boundary method along with a strong-coupling algorithm for FSI solver on overset grids. The platelet activation through the hinge for different gap sizes is compared to the activation in the bulk flow using two platelet activation models to ensure the consistency of the results. Our results for all gap sizes using different activation models show that the integration of platelet activation caused by the bulk flow is several times higher in comparison to the activation through the hinge. This work is supported by the American Heart Association Grant 13SDG17220022, and the computational resources were partly provided by Center for Computational Research (CCR) at University at Buffalo.

  10. Molecular characterization of Streptococcus mutans strains isolated from the heart valve of an infective endocarditis patient.

    Science.gov (United States)

    Nemoto, Hirotoshi; Nakano, Kazuhiko; Nomura, Ryota; Ooshima, Takashi

    2008-07-01

    Streptococcus mutans, known to be an aetiological agent of dental caries, is occasionally isolated from patients with infective endocarditis (IE). S. mutans strains with a defect in all three types of glucosyltransferase (GTF) obtained from an infected heart valve extirpated from an IE patient have been reported previously. In this study, molecular analyses of strains detected in heart valve (strain V1) and dental plaque (strain P1) samples taken from the same patient were performed. Complete nucleotide alignments of the gtfB, gtfC and gtfD regions in strains V1 and P1, as well as in the reference strain MT8148, were determined, which revealed the existence of alignments with a high similarity to erythromycin- and spectinomycin-resistance genes in the middle of the gtfB-gtfC and gtfD genes, respectively, of V1. Strain V1 also showed a higher MIC for these two antibiotics compared with strain P1. Next, primers to detect the specific sequences of the antibiotic-resistance genes in strain V1 were constructed and PCR amplification was performed with template DNA from dental plaque and infected valve tissue samples taken from the patient. Attenuated expression of GTFs in V1 caused a significantly lower susceptibility to phagocytosis by human polymorphonuclear leukocytes compared with the reference strain. These results suggest that the blood isolate V1 found in the oral cavity invaded and survived in the bloodstream for a long duration and that this was related to its virulence in IE in our patient.

  11. Aortic Valve Stenosis

    Science.gov (United States)

    ... rapid, fluttering heartbeat Not eating enough (mainly in children with aortic valve stenosis) Not gaining enough weight (mainly in children with aortic valve stenosis) The heart-weakening effects of aortic valve stenosis ...

  12. Allogenic heart valve bank in the Department of Cardiovascular Surgery and Transplantology of Jagiellonian University in Cracow - 23 years experience in the treatment of aortic valve or aortic root diseases.

    Science.gov (United States)

    Stoliński, J; Marek, G; Marcinkowska, Z; Jaskier, M; Barecka, D; Bartuś, K; Kapelak, B; Sadowski, J; Dziatkowiak, A

    2006-01-01

    Allogenic aortic valves are widely used in case of native aortic valve or root disease as well as failed prosthetic valves with great success. At the Department of Cardiovascular Surgery and Transplantology of the Jagiellonian University in Cracow, aortic valve or aortic root replacement with allogenic aortic valve has been performed for 23 years. Allogenic heart valve bank was founded in 1980. In the bank we prepare both aortic allografts for adult cardiac surgical procedures and pulmonary allografts that are mostly used for repair of congenital heart disease.Allogenic aortic valves implantation was usually considered in our clinic for older patients, patients with infective endocarditis of the native or prosthetic valve, young women in reproductive age and patients with Marfan syndrome. Allografts exhibit excellent clinical performance and acceptable durability with no early failure if properly inserted. Between 1980 and 1992, allografts were obtained only from cadavers during routine autopsies. More than 10% of prepared allografts were exported to other cardiac surgery centres in Poland and foreign countries. Aortic valve replacement using allogenic aortic valves can be performed with acceptable mortality and good long-term results. The procedure although surgically more challenging has the advantage of not requiring anticoagulation therapy, hemodynamic performance of the allogenic valve is excellent, it demonstrates freedom from thromboembolism and infective endocarditis. We would like to emphasize the importance and advantages of the fact that allogenic heart valve bank is placed in the department of cardiovascular surgery and it is able to supply the department in heart valve allografts 24 h a day.

  13. 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.)

  14. Numerical investigation on effect of aortic root geometry on flow induced structural stresses developed in a bileaflet mechanical heart valve

    Science.gov (United States)

    Abbas, S. S.; Nasif, M. S.; Said, M. A. M.; Kadhim, S. K.

    2017-10-01

    Structural stresses developed in an artificial bileaflet mechanical heart valve (BMHV) due to pulsed blood flow may cause valve failure due to yielding. In this paper, von-Mises stresses are computed and compared for BMHV placed in two types of aortic root geometries that are aortic root with axisymmetric sinuses and with axisymmetric bulb, at different physiological blood flow rates. With BMHV placed in an aortic root with axisymmetric sinuses, the von-Mises stresses developed in the valve were found to be up to 47% higher than BMHV placed in aortic root with axisymmetric bulb under similar physiological conditions. High velocity vectors and therefore high von-Mises stresses have been observed for BMHV placed in aortic root with axisymmetric sinuses, that can lead to valve failure.

  15. NT-proBNP and exercise capacity in adult patients with congenital heart disease and a prosthetic valve: a multicentre PROSTAVA study

    NARCIS (Netherlands)

    Schoonbeek, R.C.; Pieper, P.G.; Slooten, Y.J. van; Freling, H.G.; Sieswerda, G.T.; Dijk, A.P.J. van; Jongbloed, M.R.; Post, M.C.; Bouma, B.J.; Berger, R.M.; Ebels, T.; Melle, J.P. van

    2016-01-01

    OBJECTIVES: N-terminal Btype natriuretic peptide (NT-proBNP) is an important biomarker for the detection of heart failure. Adults with congenital heart disease (ACHD) and a prosthetic heart valve are at risk for heart failure. This study aimed to determine the value of NT-proBNP in ACHD patients

  16. NT-proBNP and exercise capacity in adult patients with congenital heart disease and a prosthetic valve : a multicentre PROSTAVA study

    NARCIS (Netherlands)

    Schoonbeek, R C; Pieper, P. G.; van Slooten, Y. J.; Freling, Hendrik G.; Sieswerda, G. T.; van Dijk, A. P. J.; Jongbloed, M. R. M.; Post, M. C.; Bouma, B. J.; Berger, R. M. F.; Ebels, T.; van Melle, J. P.

    2016-01-01

    Objectives N-terminal B-type natriuretic peptide (NT-proBNP) is an important biomarker for the detection of heart failure. Adults with congenital heart disease (ACHD) and a prosthetic heart valve are at risk for heart failure. This study aimed to determine the value of NT-proBNP in ACHD patients

  17. Is there a suitable method of anticoagulation in pregnant patients with mechanical prosthetic heart valves?

    Science.gov (United States)

    Malik, Humza T; Sepehripour, Amir H; Shipolini, Alex R; McCormack, David J

    2012-09-01

    A best evidence topic was written according to a structured protocol in order to identify the mode of anticoagulation that has the best safety profile for both the mother and the foetus in pregnant patients with mechanical prosthetic heart valves. A total of 281 papers were identified using the reported search, of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. The reported measures were foetal mortality, maternal mortality, congenital abnormalities and embryopathy, and maternal thromboembolic and haemorrhagic complications. The medical orthodoxy has warned of the combination of oral anticoagulation and pregnancy due to the well-documented warfarin embryopathy. Yet only one of the reported papers identified a greater incidence of foetal aberrations among warfarin use, with the highest reported rate being 6.4% and two of the assessed papers reporting no embryopathy at all. Foetal mortality with oral anticoagulation use ranged from 1.52 to 76%. All reported publications demonstrated a superior maternal outcome with warfarin use, with a range of thromboembolic events from 0 to 10% in comparison with 4 to 48% where heparin was used. Thus, it is concluded that warfarin is a more durable anticoagulant with a better maternal outcome despite it carrying a greater foetal risk. Although, in contrast to previous teaching, the risks of embryopathy are not the major drawback of oral anticoagulation. Heparin is consistently less effective, but may be preferred for the superior foetal outcome. Heparin usage during the first trimester reduces the foetal risk but is still associated with an adverse maternal outcome. While the focus for clinicians looking after pregnant women with mechanical heart valves may be to prevent maternal thromboembolic complications, the overriding concern for many women is to avoid any harm to their unborn child, even when this

  18. 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.

  19. Mitral valve prolapse

    Science.gov (United States)

    ... mitral valve prolapse is called "mitral valve prolapse syndrome," and includes: Chest pain (not caused by coronary artery disease or a heart attack) Dizziness Fatigue Panic attacks Sensation of feeling the heart beat ( palpitations ) ...

  20. [Design and construction of pulsatile-flow-cultivation system for the tissue engineering heart valve].

    Science.gov (United States)

    Feng, Bin; Liu, Yinglong; Yan, Mingquan; He, Guojian; Yu, Cuntao; Xie, Ning

    2007-06-01

    A plane, three-dimensional chamber of pulsatile-flow-cultivation and the liquid store chamber connected by medical silica gel tube were designed and constructed by ourselves according to the design principle. The rotator pump of cardiopulmonary bypass unit was acted as the power source. The mixed gas containing 5% CO2 and 95% air was supplied through the ventilation orifice of the liquid store chamber. The temperature of these components was stabilized by thermostatic waterbath. The test of biomechanics and biological compatibility for the system was carried out by cultures experiment during two weeks. The results of the experiment showed that there was no leak in the pulsatile-flow-cultivation components in which the concentration of CO2 was controlled about 5%+1%, the temperature at 37 +/- 1 degree C, and the value of pH between 6.8 and 7.5. The flow rate of the system could be adjusted exactly between 0.125 L/min and 6.0 L/min. The endothelial cells on the viable homograft valve increased about 10 times after being cultured for 2 weeks. The cultures of cell and mould taken from the leaf and Dacron cloth of homograft valve were reported to be negative. The results of the experiment demonstrated that there was satisfactory homeostasis of these components in effective modeling pulsatile-flow-field for the implantation cells cultured, proliferated, and remodeled under the condition inferior or superior to physiological level in vitro. The system can meet the need for study of pulsatile-flow-cultivation and tissue engineering heart valve constructed in vitro.

  1. Clinical outcomes of tricuspid valve repair accompanying left-sided heart disease.

    Science.gov (United States)

    Azarnoush, Kasra; Nadeemy, Ahmad S; Pereira, Bruno; Leesar, Massoud A; Lambert, Céline; Azhari, Alaa; Eljezi, Vedat; Dauphin, Nicolas; Geoffroy, Etienne; Camilleri, Lionel

    2017-10-26

    To determine whether the need for additional tricuspid valve repair is an independent risk factor when surgery is required for a left-sided heart disease. One hundred and eighty patients (68 ± 12 years, 79 males) underwent tricuspid annuoplasty. Cox proportional-hazards regression model for multivariate analysis was performed for variables found significant in univariate analyses. Tricuspid regurgitation etiology was functional in 154 cases (86%), organic in 16 cases (9%), and mixed in 10 cases (6%), respectively. Postoperative mortality at 30 days was 11.7%. Mean follow-up was 51.7 mo with survival at 5 years of 73.5%. Risk factors for mortality were acute endocarditis [hazard ratio (HR) = 9.22 (95%CI: 2.87-29.62), P explanation may lie in the fact that significant tricuspid regurgitation following left-sided heart disease represents an independent risk factor encompassing several other factors such as pulmonary arterial hypertension and dyspnea. Tricuspid annuloplasty should be used more often as a concomitant procedure in the presence of relevant tricuspid regurgitation, although it usually reveals an overly delayed correction of a left-sided heart disease.

  2. Classification of Prolapsed Mitral Valve versus Healthy Heart from Phonocardiograms by Multifractal Analysis

    Directory of Open Access Journals (Sweden)

    Ana Gavrovska

    2013-01-01

    Full Text Available Phonocardiography has shown a great potential for developing low-cost computer-aided diagnosis systems for cardiovascular monitoring. So far, most of the work reported regarding cardiosignal analysis using multifractals is oriented towards heartbeat dynamics. This paper represents a step towards automatic detection of one of the most common pathological syndromes, so-called mitral valve prolapse (MVP, using phonocardiograms and multifractal analysis. Subtle features characteristic for MVP in phonocardiograms may be difficult to detect. The approach for revealing such features should be locally based rather than globally based. Nevertheless, if their appearances are specific and frequent, they can affect a multifractal spectrum. This has been the case in our experiment with the click syndrome. Totally, 117 pediatric phonocardiographic recordings (PCGs, 8 seconds long each, obtained from 117 patients were used for PMV automatic detection. We propose a two-step algorithm to distinguish PCGs that belong to children with healthy hearts and children with prolapsed mitral valves (PMVs. Obtained results show high accuracy of the method. We achieved 96.91% accuracy on the dataset (97 recordings. Additionally, 90% accuracy is achieved for the evaluation dataset (20 recordings. Content of the datasets is confirmed by the echocardiographic screening.

  3. Hereditary spherocytosis and elliptocytosis associated with prosthetic heart valve replacement: rheological study of erythrocyte modifications.

    Science.gov (United States)

    Caprari, Patrizia; Tarzia, Anna; Mojoli, Giorgio; Cianciulli, Paolo; Mannella, Emilio; Martorana, Maria Cristina

    2009-04-01

    The implantation of a prosthetic heart valve (HVP) in patients with hereditary spherocytosis (HS) and hereditary elliptocytosis (HE) is rare, and the changes in the structure and deformability of erythrocytes that follow implantation in these patients have been poorly described. In the present study, the erythrocytes in HS and HE patients with mechanical HVP were compared to the erythrocytes in patients with only congenital membrane defects, in terms of biochemical modifications and rheological behaviour. Integral and cytoskeletal erythrocyte membrane proteins were studied, and blood viscosity (shear rate/shear stress ratio), aggregation ratio [eta(1 s(-1))/eta(200 s(-1))], and red cell visco-elasticity were determined. Valve replacement with a mechanical prosthesis worsened anaemia and resulted in a change in haemolysis, from sub-clinical to evident. The rheological investigation of erythrocytes from HS patients confirmed the characteristic increased viscosity and aggregation ratio and the decreased deformability. The rheological behaviour of erythrocytes from patients with HVP showed a decrease in viscosity and an increase in elastic modulus. In these patients, the prosthesis seems to have induced traumatic damage to the erythrocyte membrane, leading to fragmentation and lysis, which in turn modified rheological parameters. The biochemical and rheological investigation allowed us to understand the clinical and haematological pictures of the patients and to describe the role played by different factors in haemolytic anaemia.

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

    Science.gov (United States)

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

    2013-11-01

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

  5. Hemocompatibility research on the micro-structure surface of a bionic heart valve.

    Science.gov (United States)

    Ye, Xia; Wang, Ze; Zhang, Xianghua; Zhou, Ming; Cai, Lan

    2014-01-01

    In order to study how the geometric parameters and shape of the micro-structure surface of a bionic heart valve affects hemocompatibility, mastoid micro-structures with different periodic space were fabricated using a femtosecond laser on a polyurethane (PU) surface. The apparent contact angles of droplets on the micro-structure surfaces were measured to characterize their wettability. Then a series of blood compatibility experiments, including platelet adhesion, dynamic coagulation and hemolysis were completed. The experimental results showed that the micro-structure on the biomaterial surface helped improve its hydrophobicity and hemocompatibility. Also, the periodic space affected not only the hydrophobicity but also the hemocompatibility of the biomaterial. With the increasing of the periodic space, the apparent contact angle increased, the number of platelet adhesion decreased, the dynamic clotting time became longer and the hemolysis ratio reduced. In addition, the shape of the micro-structure also affected the hemocompatibility of the biomaterial.

  6. A three-dimensional fluid structure interaction method for heart valve modelling

    Science.gov (United States)

    van Loon, Raoul; Anderson, Patrick D.; Baaijens, Frank P. T.; van de Vosse, Frans N.

    2005-12-01

    A method is presented for modelling fluid-solid interaction with large transformations of a slender solid body. The fluid flow is described by the unsteady Navier-Stokes equation, and the solid deformation is described by an incompressible hyperelastic Neo-Hookean model. Although the fluid and solid mesh are non-conformal with respect to each other, both domains can be coupled using a Lagrange multiplier. Accuracy and robustness are improved by a computationally inexpensive adaptive meshing scheme which is applied to the fluid mesh at the position of the solid interface. To illustrate the applicability of this method, 2D and 3D model problems are presented that are closely related to dynamical heart-valve computations. To cite this article: R. van Loon et al., C. R. Mecanique 333 (2005).

  7. 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

    consultations (intervention) versus usual care without structured physical exercise or psycho-educational consultations (control). Primary outcome was physical capacity measured by VO2 peak and secondary outcome was self-reported mental health measured by Short Form-36. Results: 76% were men, mean age 62 years.......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...... measures of exercise capacity and self-reported outcomes. Further research is needed to justify cardiac rehabilitation in this patient group. Trial registration number NCT01558765, Results....

  8. [Electroacupuncture intervention combined with general anesthesia for 80 cases of heart valve replacement surgery under cardiopulmonary bypass].

    Science.gov (United States)

    Chi, Hao; Zhou, Wen-Xiong; Wu, Yao-Yao; Chen, Tong-Yu; Ge, Wen; Yuan, Lan; Shen, Wei-Dong; Zhou, Jia

    2014-02-01

    To determine whether electroacupuncture (EA) intervention combined with general anesthesia (GA) strategy can reduce early post-operative morbidity and medical costs in patients undergoing heart valve replacement operation under cardiopulmonary bypass. A total of 160 heart valve replacement surgery patients undergoing cardiopulmonary bypass were randomly divided into GA and EA + GA groups (n = 80 in each group). Patients of the GA group were given with intravenous injection of Fentanyl, Midazolam, Vecuronium Bromide, etc. and routine tracheal intubation. EA (3-4 Hz, 2.0-2.2 mA) was applied to bilateral Zhongfu (LU 1), Chize (LU 5) and Ximen (PC 4) beginning about 20 mm before the surgery in the EA + GA group. Endotracheal intubation was not employed but only prepared as a standby for patients of the EA + GA group. The dosage of narcotic drugs, duration of surgery, duration of aertic blockage, rate of cardiac re-beating, volumes of post-operative blood transfusion, discharge volume, cases of post-operative pulmonary infection, vocal cord injury, and the time of first bed-off, first eating and duration in intensive care unit (IOU) residence. etc. were recorded. The successful rates of heart valve replacement surgery were similar in both GA and EA + GA groups. Compared with the GA group, the dosages of Fentanyl, Midazolam and Vecuronium of the EA + GA group were significantly lower (P heart valve replacement surgery without endotracheal intubation is safe and can reduce post-operative morbidity and medical costs in patients undergoing heart valve replacement surgery under cardiopulmonary bypass.

  9. Prediction of extracellular matrix stiffness in engineered heart valve tissues based on nonwoven scaffolds.

    Science.gov (United States)

    Engelmayr, George C; Sacks, Michael S

    2008-08-01

    The in vitro development of tissue engineered heart valves (TEHV) exhibiting appropriate structural and mechanical characteristics remains a significant challenge. An important step yet to be addressed is establishing the relationship between scaffold and extracellular matrix (ECM) mechanical properties. In the present study, a composite beam model accounting for nonwoven scaffold-ECM coupling and the transmural collagen concentration distribution was developed, and utilized to retrospectively estimate the ECM effective stiffness in TEHV specimens incubated under static and cyclic flexure conditions (Engelmayr Jr et~al. in Biomaterials 26(2):175-187 2005). The ECM effective stiffness was expressed as the product of the local collagen concentration and the collagen specific stiffness (i.e., stiffness/concentration), and was related to the overall TEHV effective stiffness via an empirically determined scaffold-ECM coupling parameter and measured transmural collagen concentration distributions. The scaffold-ECM coupling parameter was determined by flexural mechanical testing of polyacrylamide gels (i.e., ECM analogs) of variable stiffness and associated scaffold-polyacrylamide gel composites (i.e., engineered tissue analogs). The transmural collagen concentration distributions were quantified from fluorescence micrographs of picro-sirius red stained TEHV sections. As suggested by a previous structural model of the nonwoven scaffold (Engelmayr Jr and Sacks in J Biomech Eng 128(4):610-622, 2006), nonwoven scaffold-ECM composites did not follow a traditional rule of mixtures. The present study provided further evidence that the primary mode of reinforcement in nonwoven scaffold-ECM composites is an increase in the number fiber-fiber bonds with a concomitant increase in the effective stiffness of the spring-like fiber segments. Simulations of potential ECM deposition scenarios using the current model indicated that the present approach is sensitive to the specific time

  10. Rationale and design of the edwards SAPIEN-3 periprosthetic leakage evaluation versus medtronic corevalve in transfemoral aortic valve implantation (ELECT) trial : A randomised comparison of balloon-expandable versus self-expanding transcatheter aortic valve prostheses

    NARCIS (Netherlands)

    Abawi, M; Agostoni, Pierfrancesco; Kooistra, N H M; Samim, M; Nijhoff, F; Voskuil, M; Nathoe, H; Doevendans, P A; Chamuleau, S A; Urgel, K; Hendrikse, J; Leiner, T; Abrahams, A C; van der Worp, B; Stella, P R

    2017-01-01

    Background and objectives Periprosthetic aortic regurgitation (PPR) after transcatheter aortic valve implantation (TAVI) remains an important issue associated with impaired long-term outcomes. The current randomised study aims to evaluate potential differences between the balloon-expandable Edwards

  11. AREVA: multicenter randomized comparison of low-dose versus standard-dose anticoagulation in patients with mechanical prosthetic heart valves.

    Science.gov (United States)

    Acar, J; Iung, B; Boissel, J P; Samama, M M; Michel, P L; Teppe, J P; Pony, J C; Breton, H L; Thomas, D; Isnard, R; de Gevigney, G; Viguier, E; Sfihi, A; Hanania, G; Ghannem, M; Mirode, A; Nemoz, C

    1996-11-01

    Moderate anticoagulation may be proposed to reduce the risk of hemorrhage for certain patients with a mechanical prosthesis, but the consequences for risk of thromboembolism are debated. The purpose of the AREVA trial was to compare moderate oral anticoagulation (international normalized ratio [INR] of 2.0 to 3.0) with the usual regimen (INR of 3.0 to 4.5) after a single-valve replacement with a mechanical prosthesis, either Omnicarbon or St Jude. Patients included were between 18 and 75 years old, in sinus rhythm, and with a left atrial diameter < or = 50 mm on the time-motion echocardiogram. Patients were randomized for INR after surgery. From 1991 to 1994, 433 patients underwent valve replacement (aortic, 414; mitral, 19) with 353 St Jude and 80 Omnicarbon prostheses; 380 patients were randomized for INR: 188 for INR 2.0 to 3.0 and 192 for INR 3.0 to 4.5. Mean follow-up was 2.2 years (1 to 4 years). Analysis of 18001 INR samples showed that the mean of the median of INR was 2.74 +/- 0.35 in the 2.0 to 3.0 group and 3.21 +/- 0.33 in the 3.0 to 4.5 group (P < .0001). Thromboembolic events, as assessed from clinical data and CT brain scans, occurred in 10 patients in the 2.0 to 3.0 INR group and 9 patients in the 3.0 to 4.5 INR group (P = .78). Hemorrhagic events occurred in 34 patients in the 2.0 to 3.0 INR group and 56 patients in the 3.0 to 4.5 INR group (P < .01), with 13 and 19 major hemorrhagic events, respectively (P = .29). In selected patients with mechanical prostheses, moderate anticoagulation prevents thromboembolic events as effectively as conventional anticoagulation and reduces the incidence of hemorrhagic events.

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

    Science.gov (United States)

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

    2012-06-01

    Multidetector computed tomography (MDCT) has diagnostic value for the evaluation of prosthetic heart valve (PHV) dysfunction but it is hampered by artefacts. We hypothesised that image acquisition using prospective triggering instead of retrospective gating would reduce artefacts related to pulsating PHV. In a pulsatile in vitro model, a mono- and bileaflet PHV were imaged using 256 MDCT at 60, 75 and 90 beats per minute (BPM) with either retrospective gating (120 kV, 600 mAs, pitch 0.2, CTDI(vol) 39.8 mGy) or prospective triggering (120 kV, 200 mAs, CTDI(vol) 13.3 mGy). Two thresholds (>175 and <-45HU), derived from the density of surrounding structures, were used for quantification of hyper- and hypodense artefacts. Image noise and artefacts were compared between protocols. Prospective triggering reduced hyperdense artefacts for both valves at every BPM (P = 0.001 all comparisons). Hypodense artefacts were reduced for the monoleaflet valve at 60 (P = 0.009), 75 (P = 0.016) and 90 BPM (P = 0.001), and for the bileaflet valves at 60 (P = 0.001), 90 (P = 0.001) but not at 75 BPM (P = 0.6). Prospective triggering reduced image noise at 60 (P = 0.001) and 75 (P < 0.03) but not at 90 BPM. Compared with retrospective gating, prospective triggering reduced most artefacts related to pulsating PHV in vitro. • Computed tomographic images are often degraded by prosthetic heart valve-induced artefacts • Prospective triggering reduces prosthetic heart valve-induced artefacts in vitro • Artefact reduction at 90 beats per minute occurs without image noise reduction • Prospective triggering may improve CT image quality of moving hyperdense structures.

  13. A case of SAPIEN XT valve fallen into left ventricle during valve-in-valve transcatheter aortic valve implantation.

    Science.gov (United States)

    Koizumi, Shigeki; Ehara, Natsuhiko; Nishiya, Kenta; Koyama, Tadaaki

    2017-06-24

    Late transcatheter heart valve embolization is a rare but life-threatening complication of transcatheter aortic valve implantation. Surgical intervention is performed for most cases, but some cases were treated by valve-in-valve transcatheter aortic valve implantation. We describe a patient in whom a 29-mm Edwards SAPIEN XT valve migrated into the left ventricular outflow tract 41 days after the initial implantation. We tried to perform valve-in-valve transcatheter aortic valve implantation using a transfemoral approach. As soon as the second transcatheter heart valve touched the first implanted valve, it fell into the left ventricle. Immediate surgical intervention was required. The first valve was removed, and surgical aortic valve replacement was successfully performed. In conclusion, we should choose surgical aortic valve replacement for late transcatheter heart valve embolization. Even if we need to treat by catheter intervention, transapical approach may be better.

  14. Cox-maze IV cryoablation and postoperative heart failure in mitral valve surgery patients.

    Science.gov (United States)

    Boano, Gabriella; Åström Aneq, Meriam; Kemppi, Jennie; Vánky, Farkas

    2017-02-01

    The indications for and the risk and benefit of concomitant surgical ablation for atrial fibrillation (AF) have not been fully delineated. Our aim was to survey whether the Cox-maze IV procedure is associated with postoperative heart failure (PHF) or other adverse short-term outcomes after mitral valve surgery (MVS). Consecutive patients with AF undergoing MVS with (n = 50) or without (n = 66) concomitant Cox-maze IV cryoablation were analysed regarding perioperative data and one-year mortality. The patients in the Maze group were younger, were in lower NYHA classes, had better right ventricular function and had lower pulmonary artery pressure. The Maze group had 30 min longer median cross-clamp time (CCT) and 50% had PHF compared with 33% in the No-maze group, p = 0.09. Two patients in the No-maze group died within one year of surgery. Congestive heart failure (OR 4.3 [CI 95%: 1.8-10], p < 0.0001) and CCT (OR 1.03 [CI 95%: 1.01-1.04], p = 0.001) were associated with PHF. The current data cannot exclude that concomitant cryoablation increases the risk for PHF, possibly by increasing the cross clamp time.

  15. A novel mechanical mitral valve replacement using Sapien XT.

    Science.gov (United States)

    Koehle, Megan; Strote, Justin A; Guadagnoli, Mark; Oldemeyer, J Bradley

    2017-06-09

    We report the case of a 66 year old female who presented to our institution fourteen years after receiving a St. Jude Mechanical Mitral Valve Replacement. She presented in refractory NYHA class IV congestive heart failure with comorbidities of acute renal failure, liver failure, and mental status changes. She was found to have immobility of one of the mitral valve disks with resultant severe mitral stenosis with a mean pressure gradient of 12 mmHg. The patient was found to have an STS predicted mortality of 39% with redo surgical MVR, and evaluation by the valve team led to a recommendation of a hybrid surgical and transcatheter procedure. The patient underwent femoral bypass and hypothermia with a sternotomy and left atrial approach. The mechanical discs were removed utilizing needle drivers without removal of the St. Jude ring. Subsequently, a 26 mm Edwards Sapien XT valve was deployed under direct and fluoroscopic visualization. The patient had an event free post-operative course, and one year following the procedure has had an outstanding clinical response with NYHA class II congestive heart failure. Her echocardiogram reveals normal valve function with a MPG of 4 mmHg without mitral regurgitation. Transatrial hybrid TMVR within the ring of a St. Jude mechanical mitral valve appears to be a feasible procedure which may be used in the future to decrease morbidity and mortality associated with high-risk redo-MVR in patients with mechanical mitral valve prostheses. © 2017 Wiley Periodicals, Inc.

  16. A comparison of dabigatran etexilate with warfarin in patients with mechanical heart valves: THE Randomized, phase II study to evaluate the safety and pharmacokinetics of oral dabigatran etexilate in patients after heart valve replacement (RE-ALIGN).

    Science.gov (United States)

    Van de Werf, Frans; Brueckmann, Martina; Connolly, Stuart J; Friedman, Jeffrey; Granger, Christopher B; Härtter, Sebastian; Harper, Ruth; Kappetein, Arie Pieter; Lehr, Thorsten; Mack, Michael J; Noack, Herbert; Eikelboom, John W

    2012-06-01

    Vitamin K antagonists are the only oral anticoagulants approved for long-term treatment of patients with a cardiac valve replacement. This study aims to test a new dosing regimen for dabigatran etexilate in patients with a mechanical bileaflet valve. Patients aged ≥ 18 years and ≤ 75 years, either undergoing implantation of a mechanical bileaflet valve (aortic or mitral or both) during the current hospital stay or having undergone implantation a mitral bileaflet valve >3 months before randomization, will be randomized between dabigatran etexilate or warfarin (in a ratio of 2:1) in an open-label design. Initial doses of dabigatran will be based on the estimated creatinine clearance, and the doses will be adjusted based on measuring trough dabigatran plasma levels to achieve levels ≥ 50 ng/mL at steady state. Doses will range between 150 mg twice a day and 300 mg twice a day. Warfarin management and target international normalized ratio will be according to current practice guidelines at the discretion of the treating physicians. The plan is to treat 270 patients with dabigatran etexilate for a total study population of approximately 405 patients. Clinical efficacy and safety outcomes will be analyzed in an exploratory manner. RE-ALIGN is the first study to test an alternative to warfarin in patients with mechanical heart valves. A definitive phase III study will be planned based on the results of this study. Copyright © 2012 Mosby, Inc. All rights reserved.

  17. Flow Structure Downstream of a Mechanical Heart Valve during Systole: Investigation Using High-Speed Particle Image Velocimetry

    Science.gov (United States)

    Oshkai, Peter; Haji-Esmaeili, Farida

    2007-11-01

    High speed digital particle image velocimetry is employed to study turbulent flow through a bileaflet mechanical heart valve during systolic and diastolic phases of a cardiac cycle. Unsteady vortex shedding from the valve's leaflets displays distinct characteristic frequencies, depending on the opening angle of each leaflet. Small- and large-scale transverse oscillations of the separated shear layers are studied using global quantitative flow imaging approach. Implementation of high-speed digital particle image velocimetry technique yields quantitative information about vortex shedding frequencies and trajectories of the shed vortices downstream of the valve. Turbulent flow structures including jet-like regions and shed vortices are characterized in terms of patterns of instantaneous and time-averaged velocity, vorticity, and streamline topology.

  18. Distant downstream steady-state flow studies of a mechanical heart valve: PIV study of secondary flow in a model aortic arch

    Science.gov (United States)

    Fix, Brandon R.; Popma, Christopher J.; Bulusu, Kartik V.; Plesniak, Michael W.

    2013-11-01

    Each year, hundreds of thousands of aortic and mitral heart valves are replaced with prosthetic valves. In efforts to develop a valve that does not require lifelong anticoagulation therapy, previous experimental research has been devoted to analyzing the hemodynamics of various heart valve designs, limited to the flow up to only 2 diameters downstream of the valve. Two-component, two-dimensional (2C-2D) particle image velocimetry (PIV) was used in this study to examine secondary flow velocity fields in a curved tube modeling an aorta at five locations (0-, 45-, 90-, 135-, 180-degrees). A bileaflet valve, opened to 30-, 45-, and 59-degrees, and one (no-valve) baseline condition were examined under three steady flow inflows (Re = 218, 429, 634). In particular, variations in the two-dimensional turbulent shear stresses at each cross sectional plane were analyzed. The results suggest that bileaflet valves in the aortic model produce significant turbulence and vorticity up to 5.5 downstream diameters, i.e. up to the 90-degrees location. Expanding this research towards aortic heart valve hemodynamics highlights a need for additional studies extending beyond the typical few diameters downstream to fully characterize valvular function. Supported by the NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

  19. Augmented reality image guidance improves navigation for beating heart mitral valve repair.

    Science.gov (United States)

    Chu, Michael W A; Moore, John; Peters, Terry; Bainbridge, Daniel; McCarty, David; Guiraudon, Gerard M; Wedlake, Chris; Lang, Pencilla; Rajchl, Martin; Currie, Maria E; Daly, Richard C; Kiaii, Bob

    2012-01-01

    Emerging off-pump beating heart valve repair techniques offer patients less invasive alternatives for mitral valve (MV) repair. However, most of these techniques rely on the limited spatial and temporal resolution of transesophageal echocardiography (TEE) alone, which can make tool visualization and guidance challenging. Using a magnetic tracking system and integrated sensors, we created an augmented reality (AR) environment displaying virtual representations of important intracardiac landmarks registered to biplane TEE imaging. In a porcine model, we evaluated the AR guidance system versus TEE alone using the transapically delivered NeoChord DS1000 system to perform MV repair with chordal reconstruction. Successful tool navigation from left ventricular apex to MV leaflet was achieved in 12 of 12 and 9 of 12 (P = 0.2) attempts with AR imaging and TEE alone, respectively. The distance errors of the tracked tool tip from the intended midline trajectory (5.2 ± 2.4 mm vs 16.8 ± 10.9 mm, P = 0.003), navigation times (16.7 ± 8.0 seconds vs 92.0 ± 84.5 seconds, P = 0.004), and total path lengths (225.2 ± 120.3 mm vs 1128.9 ± 931.1 mm, P = 0.003) were significantly shorter in the AR-guided trials compared with navigation with TEE alone. Furthermore, the potential for injury to other intracardiac structures was nearly 40-fold lower when using the AR imaging for tool navigation. The AR guidance also seemed to shorten the learning curve for novice surgeons. Augmented reality-enhanced TEE facilitates more direct and safe intracardiac navigation of the NeoChord DS tool from left ventricular apex to MV leaflet. Tracked tool path results demonstrate fourfold improved accuracy, fivefold shorter navigation times, and overall improved safety with AR imaging guidance.

  20. Evaluation of transcatheter heart valve biomaterials: Biomechanical characterization of bovine and porcine pericardium.

    Science.gov (United States)

    Caballero, Andrés; Sulejmani, Fatiesa; Martin, Caitlin; Pham, Thuy; Sun, Wei

    2017-11-01

    Bovine pericardium (BP) has been identified as a choice biomaterial for the development of surgical bioprosthetic heart valves (BHV) and transcatheter aortic valves (TAV). Porcine pericardium (PP) and younger BP have been suggested as candidates TAV leaflet biomaterials for smaller-profile devices due to their reduced thickness; however, their mechanical and structural properties remain to be fully characterized. This study characterized the material properties of chemically treated thick (PPK) and thin (PPN) PP, as well as fetal (FBP), calf (CBP) and adult (ABP) BP tissues in order to better understand their mechanical behavior. Planar biaxial testing and uniaxial failure testing methods were employed to quantify tissue mechanical responses and failure properties. Fiber characteristics were examined using histological analysis. ABP and CBP tissues were significantly stiffer and stronger than the younger FBP tissues. Histological analysis revealed a significantly larger concentration of thin immature collagen fibers in the FBP tissues than in the ABP and CBP tissues. While PP tissues were thinnest, they were stiffer and less extensible than the BP tissues. Due to comparable mechanical properties but significantly reduced thickness, CBP tissue may be a more suitable material for TAV manufacturing than ABP tissue. FBP tissue, despite its reduced thickness and higher flexibility, was weaker and should be studied in more detail. Although PP tissues are the thinnest, they were least extensible and failed at earlier strain than BP tissues. The differences between PP and BP tissues should be further investigated and suggest that they should not be used interchangeably in the manufacturing of TAV. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. How Heart Valves Evolve to Adapt to an Extreme-Pressure System

    DEFF Research Database (Denmark)

    Amstrup Funder, Jonas; Christian Danielsen, Carl; Baandrup, Ulrik

    2017-01-01

    than those of calves. The elastin contents of the pulmonary valves (2.5%) and aortic valves (1.5%) were also higher in giraffes. CONCLUSIONS: The greater strength of the giraffe aortic valve is most likely due to a compact collagen construction. Both, collagen and elastin contents were higher...

  2. A mitral annulus tracking approach for navigation of off-pump beating heart mitral valve repair.

    Science.gov (United States)

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

    2015-01-01

    To develop and validate a real-time mitral valve annulus (MVA) tracking approach based on biplane transesophageal echocardiogram (TEE) data and magnetic tracking systems (MTS) to be used in minimally invasive off-pump beating heart mitral valve repair (MVR). The authors' guidance system consists of three major components: TEE, magnetic tracking system, and an image guidance software platform. TEE provides real-time intraoperative images to show the cardiac motion and intracardiac surgical tools. The magnetic tracking system tracks the TEE probe and the surgical tools. The software platform integrates the TEE image planes and the virtual model of the tools and the MVA model on the screen. The authors' MVA tracking approach, which aims to update the MVA model in near real-time, comprises of three steps: image based gating, predictive reinitialization, and registration based MVA tracking. The image based gating step uses a small patch centered at each MVA point in the TEE images to identify images at optimal cardiac phases for updating the position of the MVA. The predictive reinitialization step uses the position and orientation of the TEE probe provided by the magnetic tracking system to predict the position of the MVA points in the TEE images and uses them for the initialization of the registration component. The registration based MVA tracking step aims to locate the MVA points in the images selected by the image based gating component by performing image based registration. The validation of the MVA tracking approach was performed in a phantom study and a retrospective study on porcine data. In the phantom study, controlled translations were applied to the phantom and the tracked MVA was compared to its "true" position estimated based on a magnetic sensor attached to the phantom. The MVA tracking accuracy was 1.29 ± 0.58 mm when the translation distance is about 1 cm, and increased to 2.85 ± 1.19 mm when the translation distance is about 3 cm. In the study on

  3. Functional Heart Valve Scaffolds Obtained by Complete Decellularization of Porcine Aortic Roots in a Novel Differential Pressure Gradient Perfusion System.

    Science.gov (United States)

    Sierad, Leslie Neil; Shaw, Eliza Laine; Bina, Alexander; Brazile, Bryn; Rierson, Nicholas; Patnaik, Sourav S; Kennamer, Allison; Odum, Rebekah; Cotoi, Ovidiu; Terezia, Preda; Branzaniuc, Klara; Smallwood, Harrison; Deac, Radu; Egyed, Imre; Pavai, Zoltan; Szanto, Annamaria; Harceaga, Lucian; Suciu, Horatiu; Raicea, Victor; Olah, Peter; Simionescu, Agneta; Liao, Jun; Movileanu, Ionela; Harpa, Marius; Simionescu, Dan Teodor

    2015-12-01

    There is a great need for living valve replacements for patients of all ages. Such constructs could be built by tissue engineering, with perspective of the unique structure and biology of the aortic root. The aortic valve root is composed of several different tissues, and careful structural and functional consideration has to be given to each segment and component. Previous work has shown that immersion techniques are inadequate for whole-root decellularization, with the aortic wall segment being particularly resistant to decellularization. The aim of this study was to develop a differential pressure gradient perfusion system capable of being rigorous enough to decellularize the aortic root wall while gentle enough to preserve the integrity of the cusps. Fresh porcine aortic roots have been subjected to various regimens of perfusion decellularization using detergents and enzymes and results compared to immersion decellularized roots. Success criteria for evaluation of each root segment (cusp, muscle, sinus, wall) for decellularization completeness, tissue integrity, and valve functionality were defined using complementary methods of cell analysis (histology with nuclear and matrix stains and DNA analysis), biomechanics (biaxial and bending tests), and physiologic heart valve bioreactor testing (with advanced image analysis of open-close cycles and geometric orifice area measurement). Fully acellular porcine roots treated with the optimized method exhibited preserved macroscopic structures and microscopic matrix components, which translated into conserved anisotropic mechanical properties, including bending and excellent valve functionality when tested in aortic flow and pressure conditions. This study highlighted the importance of (1) adapting decellularization methods to specific target tissues, (2) combining several methods of cell analysis compared to relying solely on histology, (3) developing relevant valve-specific mechanical tests, and (4) in vitro testing

  4. Urgent Transcatheter Aortic Valve Implantation in Patients With Severe Aortic Stenosis and Acute Heart Failure: Procedural and 30-Day Outcomes.

    Science.gov (United States)

    Landes, Uri; Orvin, Katia; Codner, Pablo; Assali, Abid; Vaknin-Assa, Hana; Schwartznberg, Shmuel; Levi, Amos; Shapira, Yaron; Sagie, Alexander; Kornowski, Ran

    2016-06-01

    Transcatheter aortic valve implantation (TAVI) is recommended for patients with severe symptomatic aortic stenosis (AS) who are at prohibitive/high risk for surgical aortic valve replacement (SAVR). Patients with severe AS may experience acute decompensated heart failure (HF) that is resistant to medical therapy. We report our TAVI experience in treating patients with unstable AS who require urgent intervention for their aortic valve disease. Patients were restrictively included in the urgent TAVI registry if they were admitted with acute refractory and persistent HF despite medical therapy and had TAVI performed during the same hospital stay. All others were included in the elective TAVI group. Between November 2008 and April 2015, 410 consecutive patients underwent TAVI at our centre-27 (6.6%) urgently. Patients operated on urgently were more likely to be frail and carry higher SAVR mortality risk based on The Society of Thoracic Surgeons Predicted Risk of Mortality/logistic EuroSCORE (LES) measures. Pulmonary edema was the most common clinical presentation. Preprocedural assessment used fewer imaging modalities, yet implantation success remained high and reached 96.3% using an additional valve (valve-within-valve) required in 3 patients, with no difference in periprocedural complications according to the Valve Academic Research Consortium-2 definitions. Although 30-day functional capacity was reduced, patients had similar 30-day mortality and major adverse cardiovascular event rates compared with patients who underwent elective TAVI. Short-term outcome after urgent TAVI appears to be reasonable. For patients with severe AS who experience acute decompensated HF that is recalcitrant to optimal medical therapy and who are at high risk with SAVR, urgent TAVI may be a viable treatment strategy. Larger prospective studies and data on long-term outcomes are needed. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  5. Microstructural alterations owing to handling of bovine pericardium to manufacture bioprosthetic heart valves: A potential risk for cusp dehiscence.

    Science.gov (United States)

    Mao, J; Wang, Y; Philippe, E; Cianciulli, T; Vesely, I; How, D; Bourget, J-M; Germain, L; Zhang, Z; Guidoin, R

    2017-06-01

    Cross-linking and anti-calcification of prosthetic heart valves have been continuously improved to prevent degeneration and calcification. However, non-calcific structural deteriorations such as cuspal dehiscences along the stent still require further analysis. Based upon the previous analysis of an explanted valve after 7 years, a fresh commercial aortic valve was embedded in poly(methyl methacrylate) (PMMA) and cut into slices to ensure the detailed observation of the assembly and material structures. A pericardial patch embossed to provide the adequate shape of the cusps was investigated after paraffin embedding and appropriate staining. The microstructural damages that occurred during manufacturing process were identified and evaluated by light microscopy, polarized microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The wavy collagen bundles, the key structure of the pericardium patch, were damaged to a great extent at suture sites along the stent and in the compressed areas around the stent post. The fixation of the embossed pericardium patch along the plots of the stent aggravated the microstructural modifications. The damages mainly appeared as the elimination of collagen bundle waviness and delamination between the bundles. Considering the modes of failure of the explant, the damages to the collagen bundles may identify the vulnerable sites that play an important role in the cusp dehiscence of heart valve implants. Such information is important to the manufacturers. Recommendations to prevent in vivo cusp dehiscence can therefore be formulated. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. 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.

  7. Timing of anticoagulant re-initiation following intracerebral hemorrhage in mechanical heart valves: Survey of neurosurgeons and thrombosis experts.

    Science.gov (United States)

    AlKherayf, Fahad; Xu, Yan; Westwick, Harrison; Moldovan, Ioana Doina; Wells, Philip S

    2017-03-01

    While oral anticoagulation (OAC) is universally indicated for patients with mechanical heart valves (MHVs), OAC resumption following anticoagulant-associated intracerebral hemorrhage (ICH) is an area of uncertainty. We sought to determine the practice preferences of North American neurosurgeons and thrombosis experts on optimal timing of OAC re-initiation. A cross-sectional survey was disseminated to North American members of the American Association of Neurological Surgeons and the International Society for Thrombosis and Haemostasis. Demographic factors, as well as a clinical scenario with 14 modifiable clinical risk factors were included in the survey. 504 physicians completed our survey (response rate 34.3%). Majority of participants were affiliated with academic centres, and managed≤10 ICH patients with MHV per year. There was wide distribution in response in optimal timing for OAC resumption following an ICH: 59% and 60% preferred to re-start OAC between 3 and 14 days following the hemorrhagic event (median of 6-7 days). Smaller hemorrhages (valve prosthesis, caged-ball valves and multiple valves prompted earlier OAC resumption. Wide variation in the current practice of neurosurgeons and thrombosis specialists exist when they encounter patients with ICH and MHV, though decisions were influenced by patient- and valve-related factors. As our observed variation likely reflects the immense gap in current evidence, prospective randomized trials in this population are therefore urgently needed. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Preliminary experience with porcine intestinal submucosa (CorMatrix) for valve reconstruction in congenital heart disease: histologic evaluation of explanted valves.

    Science.gov (United States)

    Zaidi, Abbas Haider; Nathan, Meena; Emani, Sitaram; Baird, Christopher; del Nido, Pedro J; Gauvreau, Kimberlee; Harris, Marian; Sanders, Stephen P; Padera, Robert F

    2014-11-01

    We compared the histologic findings in explanted CorMatrix (9 patients) and autologous pericardium (9 patients) used for valvuloplasty of the aortic (7 patients) and/or mitral (11 patients) valve in patients with congenital heart defects. We used standard tissue stains and immunohistochemistry to identify the inflammatory cell type. CorMatrix was associated with an intense inflammatory response in the surrounding native tissue, extending into CorMatrix in 8 of 9 cases, continuing to the longest follow-up point (9 months). The typical response included macrophages and giant cells in contact with the material, surrounded by lymphocytes, macrophages, plasma cells, and eosinophils. The thickness of the residual CorMatrix material was 280 to 300 μm, similar to the nominal thickness at implantation and unrelated to the implantation duration. Only at the longest follow-up interval was any significant resorption of CorMatrix material evident. A neointima had formed on the surface of CorMatrix, increasing in thickness with the period in situ. Mild cellular infiltration of CorMatrix was noted in all cases; however, in no case, did it appear that CorMatrix was being remodeled into tissue resembling a 3-layered native valve. In contrast, a near absence of any inflammatory reaction was seen and no eosinophilia associated with autologous pericardium was present, irrespective of the duration in situ. Furthermore, we observed more tissue infiltration, remodeling, vascularization, and neointima formation with autologous pericardium. Although CorMatrix used for valve repair induced an intense inflammatory response, little or no remodeling to form tissue resembling a 3-layered native valve was seen at ≤9 months after implantation. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  9. Understanding the requirements of self-expandable stents for heart valve replacement: Radial force, hoop force and equilibrium.

    Science.gov (United States)

    Cabrera, María Sol; Oomens, Cees W J; Baaijens, Frank P T

    2017-04-01

    A proper interpretation of the forces developed during stent crimping and deployment is of paramount importance for a better understanding of the requirements for successful heart valve replacement. The present study combines experimental and computational methods to assess the performance of a nitinol stent for tissue-engineered heart valve implantation. To validate the stent model, the mechanical response to parallel plate compression and radial crimping was evaluated experimentally. Finite element simulations showed good agreement with the experimental findings. The computational models were further used to determine the hoop force on the stent and radial force on a rigid tool during crimping and self-expansion. In addition, stent deployment against ovine and human pulmonary arteries was simulated to determine the hoop force on the stent-artery system and the equilibrium diameter for different degrees of oversizing. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Effects of Mechanical Ventilation on Heart Geometry and Mitral Valve Leaflet Coaptation During Percutaneous Edge-to-Edge Mitral Valve Repair.

    Science.gov (United States)

    Patzelt, Johannes; Zhang, Yingying; Seizer, Peter; Magunia, Harry; Henning, Andreas; Riemlova, Veronika; Patzelt, Tara A E; Hansen, Marc; Haap, Michael; Riessen, Reimer; Lausberg, Henning; Walker, Tobias; Reutershan, Joerg; Schlensak, Christian; Grasshoff, Christian; Simon, Dan I; Rosenberger, Peter; Schreieck, Juergen; Gawaz, Meinrad; Langer, Harald F

    2016-01-25

    This study sought to evaluate a ventilation maneuver to facilitate percutaneous edge-to-edge mitral valve repair (PMVR) and its effects on heart geometry. In patients with challenging anatomy, the application of PMVR is limited, potentially resulting in insufficient reduction of mitral regurgitation (MR) or clip detachment. Under general anesthesia, however, ventilation maneuvers can be used to facilitate PMVR. A total of 50 consecutive patients undergoing PMVR were included. During mechanical ventilation, different levels of positive end-expiratory pressure (PEEP) were applied, and parameters of heart geometry were assessed using transesophageal echocardiography. We found that increased PEEP results in elevated central venous pressure. Specifically, central venous pressure increased from 14.0 ± 6.5 mm Hg (PEEP 3 mm Hg) to 19.3 ± 5.9 mm Hg (PEEP 20 mm Hg; p 4.9 mm at PEEP of 10 mm Hg resulted in a significant reduction of PMVR procedure time (152 ± 49 min to 116 ± 26 min; p = 0.05). In this study, we describe a novel ventilation maneuver improving mitral valve coaptation length during the PMVR procedure, which facilitates clip positioning. Our observations could help to improve PMVR therapy and could make nonsurgical candidates accessible to PMVR therapy, particularly in challenging cases with functional MR. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  11. Outcomes for the Commercial Use of Self-Expanding Prostheses in Transcatheter Aortic Valve Replacement: A Report From the STS/ACC TVT Registry.

    Science.gov (United States)

    Sorajja, Paul; Kodali, Susheel; Reardon, Michael J; Szeto, Wilson Y; Chetcuti, Stanley J; Hermiller, James; Chenoweth, Sharla; Adams, David H; Popma, Jeffrey J

    2017-10-23

    The authors sought to compare the outcomes of commercial transcatheter aortic valve replacement (TAVR) with the repositionable Evolut R platform to those observed with the CoreValve device in the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapy (TVT) Registry. TAVR continues to evolve, with rapid adoption of iterative changes for commercial practice. Insight into the outcomes of this adoption is needed. Patients in the TVT Registry who had TAVR using a 23-, 26-, or 29-mm self-expanding prosthesis were enrolled. Site-reported events for procedural, in-hospital, and 30-day outcomes were examined. Between January 2014 and April 2016, 9,616 patients underwent TAVR with a self-expanding prosthesis with data entered in the TVT Registry. Compared with patients treated with CoreValve TAVR, those who received Evolut R TAVR had a lower STS-PROM score (8.0 ± 5.4% vs. 8.7 ± 5.3%; p < 0.001), more iliofemoral access (91.6% vs. 89.2%; p < 0.001), and more frequently had conscious sedation (27.4% vs. 12.7%; p < 0.001). With Evolut R TAVR, there was less need for a second prosthesis (2.2% vs. 4.5%; p < 0.001), less device migration (0.2% vs. 0.6%; p = 0.01), a lower incidence of moderate/severe paravalvular regurgitation (post-procedure, 4.4% vs. 6.2%; p < 0.001), and shorter median hospital stay (4.0 vs. 5.0 days; p < 0.001). Patients treated with Evolut R TAVR had greater device success (96.3% vs. 94.9%; p = 0.001). At 30 days, Evolut R patients had both lower mortality (3.7% vs. 5.3%; p < 0.001) and less need for a pacemaker (18.3% vs. 20.1%; p = 0.03). Commercial adoption of the Evolut R platform is associated with significant improvements in acute outcomes for patients undergoing TAVR for aortic stenosis. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  12. Flow characteristics past jellyfish and St. Vincent valves in the aortic position under physiological pulsatile flow conditions.

    Science.gov (United States)

    Morsi, Y S; Sakhaeimanesh, A A

    2000-07-01

    Thrombus formation and hemolysis have been linked to the dynamic flow characteristics of heart valve prostheses. To enhance our understanding of the flow characteristics past the aortic position of a Jellyfish (JF) valve in the left ventricle, in vitro laser Doppler anemometry (LDA) measurements were carried out under physiological pulsatile flow conditions. The hemodynamic performance of the JF valve was then compared with that of the St. Vincent (SV) valve. The comparison was given in terms of mean systolic pressure drop, back flow energy losses, flow velocity, and shear stresses at various locations downstream of both valves and at cardiac outputs of 3.5 L/min, 4.5 L/min, and 6.5 L/min respectively. The results indicated that both valves created disturbed flow fields with elevated levels of turbulent shear stress as well as higher levels of turbulence in the immediate vicinity of the valve and up to 1 diameter of the pipe (D) downstream of the valve. At a location further downstream, the JF valve showed better flow characteristics than the SV in terms of velocity profiles and turbulent shear stresses. The closure volume of the SV valve was found to be 2.5 times higher than that of the JF valve. Moreover, the total back flow losses and mean systolic pressure drop also were found to be higher in the SV than the JF valve.

  13. Principal stress analysis in LDA measurement of the flow field downstream of 19-mm Sorin Bicarbon heart valve.

    Science.gov (United States)

    Barbaro, V; Grigioni, M; Daniele, C; D'Avenio, G

    1998-11-01

    Heart valve replacement has become, since many years, a common surgical practice. Along with the improvement that the patients' health has derived from it, however, a certain amount of risk could not be avoided, bound to the inevitable hemodynamic disturbances that an artificial device generates. A major shortcoming, often reported, is the formation of thrombus on the edge of the prosthetic valve, with a possible obstruction of the orifices through which blood should normally flow undisturbed. Hemolysis is another possible consequence of the implantation of a mechanical heart valve, generally correlated to turbulence downstream of prosthetic heart valves (PHV). As it is agreed upon by many researchers, the risk of thrombogenicity or hemolysis is higher in those valves that are more subject to promote turbulence and flow separation in the flow through them. In the following paper, we present a study of the turbulence-related shear stress downstream of a bileaflet valve of minimum size (19 mm external diameter) Sorin Bicarbon. This size was chosen, accordingly to the Food & Drug Administration (FDA) draft guidance suggestion to investigate the worst case in turbulence promoted by PHVs, in order to have the highest velocity gradients and shear stresses for the FDA-stated cardiac output (6 1/min), related to maximum Reynolds number conditions. Velocity data were collected with the two-dimensional laser Doppler anemometry (LDA) technique; whereas this approach does not investigate directly all three components of the flow field, in the present case (bileaflet valves) it is not a limitation to the assessment of the maximum turbulence shear stress (TSS), thanks to the two-dimensional flow nature downstream of bileaflet models. Data taken in coincident mode were elaborated in order to determine the maximum shear stress in the measured points in the flow field, using the 2D Principal Stress Analysis (PSA). The consequences of a variable principal normal stress direction all

  14. Effects of tranexamic acid on coagulation indexes of patients undergoing heart valve replacement surgery under cardiopulmonary bypass.

    Science.gov (United States)

    Liu, Fei; Xu, Dong; Zhang, Kefeng; Zhang, Jian

    2016-12-01

    This study aims to explore the effects of tranexamic acid on the coagulation indexes of patients undergoing heart valve replacement surgery under the condition of cardiopulmonary bypass (CPB). One hundred patients who conformed to the inclusive criteria were selected and divided into a tranexamic acid group and a non-tranexamic acid group. They all underwent heart valve replacement surgery under CPB. Patients in the tranexamic acid group were intravenously injected with 1 g of tranexamic acid (100 mL) at the time point after anesthesia induction and before skin incision and at the time point after the neutralization of heparin. Patients in the non-tranexamic acid group were given 100 mL of normal saline at corresponding time points, respectively. Then the coagulation indexes of the two groups were analyzed. The activated blood clotting time (ACT) of the two groups was within normal scope before CPB, while four coagulation indexes including prothrombin time (PT), activated partial thromboplastin time (APTT), international normalized ratio (INR), and fibrinogen (FIB) had significant increases after surgery; the PT and INR of the tranexamic acid group had a remarkable decline after surgery. All the findings suggest that the application of tranexamic acid in heart valve replacement surgery under CPB can effectively reduce intraoperative and postoperative blood loss. © The Author(s) 2016.

  15. Verification of pharmacogenetics-based warfarin dosing algorithms in Han-Chinese patients undertaking mechanic heart valve replacement.

    Science.gov (United States)

    Zhao, Li; Chen, Chunxia; Li, Bei; Dong, Li; Guo, Yingqiang; Xiao, Xijun; Zhang, Eryong; Qin, Li

    2014-01-01

    To study the performance of pharmacogenetics-based warfarin dosing algorithms in the initial and the stable warfarin treatment phases in a cohort of Han-Chinese patients undertaking mechanic heart valve replacement. We searched PubMed, Chinese National Knowledge Infrastructure and Wanfang databases for selecting pharmacogenetics-based warfarin dosing models. Patients with mechanic heart valve replacement were consecutively recruited between March 2012 and July 2012. The predicted warfarin dose of each patient was calculated and compared with the observed initial and stable warfarin doses. The percentage of patients whose predicted dose fell within 20% of their actual therapeutic dose (percentage within 20%), and the mean absolute error (MAE) were utilized to evaluate the predictive accuracy of all the selected algorithms. A total of 8 algorithms including Du, Huang, Miao, Wei, Zhang, Lou, Gage, and International Warfarin Pharmacogenetics Consortium (IWPC) model, were tested in 181 patients. The MAE of the Gage, IWPC and 6 Han-Chinese pharmacogenetics-based warfarin dosing algorithms was less than 0.6 mg/day in accuracy and the percentage within 20% exceeded 45% in all of the selected models in both the initial and the stable treatment stages. When patients were stratified according to the warfarin dose range, all of the equations demonstrated better performance in the ideal-dose range (1.88-4.38 mg/day) than the low-dose range (mechanic heart valve replacement.

  16. Characterization of Dermal Fibroblasts as a Cell Source for Pediatric Tissue Engineered Heart Valves

    Directory of Open Access Journals (Sweden)

    Monica M. Fahrenholtz

    2014-08-01

    Full Text Available There is continued debate regarding the appropriate cell type to replace valvular interstitial cells (VICs in tissue engineered heart valves (TEHVs, particularly for pediatric patients. In this work, neonatal human dermal fibroblasts (nhDFFs were compared to human pediatric VICs (hpVICs, based on their phenotypic and gene expression characteristics when cultured on collagen type I, fibronectin, fibrin, and tissue culture polystyrene (TCP substrates. Similar confluency was achieved over the culture period on collagen and fibronectin between both cell types, although nhDFFs tended to reach lower confluence on collagen than on any other substrate. Morphologically, hpVICs tended to spread and form multiple extensions, while nhDFFs remained homogenously spindle-shaped on all substrates. PCR results indicated that fibroblasts did not differ significantly from VICs in gene expression when cultured on fibrin, whereas on collagen type I and fibronectin they showed increased α-SMA, xylosyltransferase I, and collagen type I expression (p < 0.05. However, protein expression of these targets, analyzed by immunocytochemistry and Western blotting, was not significantly different between cell types. These results suggest that nhDFFs express similar matrix production and remodeling genes as hpVICs, and the choice of substrate for TEHV construction can affect the growth and expression profile of nhDFFs as compared to native hpVICs.

  17. The effects of Ramadan fasting on patients with prosthetic heart valve taking warfarin for anticoagulation.

    Science.gov (United States)

    Awiwi, Muhammad O; Yagli, Zeynep Aslan; Elbir, Ferruh; Aglar, Ahmet Arif; Guler, Erhan; Vural, Unsal

    2017-01-01

    Oral anticoagulation with warfarin is indicated for patients with prosthetic heart valves. The effects of religious fasting during Ramadan month (in the Islamic calendar) on anticoagulation aren't clear. To study the impact of Ramadan fasting on international normalized ratio (INR), quality of anticoagulation, dose of warfarin used and blood osmolarity. 18 patients were followed-up prospectively for 3 months (pre- Ramadan, Ramadan and post-Ramadan months). Patients presented for weekly visits in which blood samples were obtained. No significant difference in INR and warfarin dose was found between Ramadan month, and months before and after it. The post-Ramadan INR was significantly larger than pre-Ramadan (p = 0.004). Blood osmolarity was significantly lower during Ramadan compared to pre- and post-Ramadan months. A significantly better quality of anticoagulation was noticed during Ramadan (p Ramadan month (p Ramadan month (p Ramadan. A tendency toward supra-therapeutic anticoagulation occurred after Ramadan, thus a closer follow up during this period may be reasonable.

  18. Body image after heart transplantation compared to mechanical aortic valve insertion.

    Science.gov (United States)

    Hartmann, Armin; Heilmann, Claudia; Kaps, Josefine; Beyersdorf, Friedhelm; Zeh, Wolfgang; Albert, Wolfgang; Wirsching, Michael; Fritzsche, Kurt; Joos, Andreas

    2017-11-01

    Heart transplantation (HT) obviously affects body image and integrity. However, there are very few empirical data post-transplant. In a cross-sectional study, 57 HT patients were compared with 47 subjects with mechanical aortic valve replacement (AVR) using the Dresden-Body-Image questionnaire (DKB) and specific questions regarding integration of the organ/device. In addition, affective symptoms and quality of life (QoL) were assessed (12-Item Short-Form Health Survey and Hospital Anxiety and Depression Scale, HADS). DKB-35 scores did not differ. HT patients scored higher than AVR on specific questions regarding integration of the organ/device. AVR patients showed more affective disturbance and lower mental QoL than HT subjects. Affective scores correlated negatively with body image scores. Seventeen percent of all patients showed psychological distress (HADS scores >8). HT patients integrated the new organ well - and even better than AVR subjects did with the device. In general, our data corroborate a good adaptation process, in particular in HT patients. Similar to other reported data, a subgroup of 15-20% of patients shows stronger mental distress, including body image problems. These must be identified and treated by professionals. Patients with AVR deserve more attention in the future.

  19. Mechanism of Microbubble Growth at Mitral Mechanical Heart Valve (MHV) Closure

    Science.gov (United States)

    Rambod, Edmond; Beizaie, Masoud; Shusser, Michael; Gharib, Morteza

    1999-11-01

    The growth mechanism of microbubbles at mitral MHV closure has been experimentally studied. In the heart, some of the tiny bubbles grow explosively and form larger and persistent bubbles. An experimental set-up was designed to allow the passage of micron-size bubbles through an 80 micron-wide slot, simulating a typical gap between the housing ring and the occluders in MHV. The bubbles were generated using an air-liquid dispenser and were delivered to the system via a 250 micron-diameter hypedermic needle positioned vertically near the slot. A solenoid valve was used to deliver a 10cc volume of liquid in 25ms time through the slot. High-speed imaging was used to study the impact of flow through the slot on bubble growth. The velocity of liquid through the slot was assessed to be in the range of 12-15 m/s. Our observations confirmed the rapid and drastic growth of microbubbles following their passage through the narrow slot, due to pressure drop. Vortices, which were induced by flow separation on the downstream of the slot, caused the grown bubbles to shatter and form more stable bubbles.

  20. Gamma radiation alters the ultrastructure in tissue-engineered heart valve scaffolds.

    Science.gov (United States)

    Somers, Pamela; Cuvelier, Claude A; Somer, Filip De; Cornelissen, Maria; Cox, Eric; Verloo, Marc; Chiers, Koen; van Nooten, Guido

    2009-11-01

    Xenogenic extracellular heart valve matrices have been suggested as scaffolds for tissue engineering. However, these matrices are immunogenic and stimulate an intense cell-mediated immune response and calcification. Mitigating the immunogenicity was attempted by different doses of gamma irradiation. Mechanical properties of gamma-irradiated porcine matrices and control matrices (nonirradiated) were examined by tensile strength testing. Irradiated matrices (1, 10, 50, and 100 gray [Gy]) and control matrices were implanted subcutaneously in Wistar rats (n = 20). After 24 h, 1, 2, 3, and 4 weeks the explants were examined by light microscopy and transmission electron microscopy. Calcium (Ca) content was determined using inductively coupled plasma-mass spectrometry. Antibody reaction against porcine tissue in the rat serum was determined. Tensile strength increased in irradiated matrices at the expense of elasticity. Ten gray-irradiated leaflets showed minimal lymphocytic inflammatory infiltration with preservation of ultrastructure. Ca levels after 2 weeks were as follows: control (0 Gy), 388 +/- 264 microg/mg; 1 Gy, 240 +/- 95 microg/mg; 10 Gy, 188 +/- 54 microg/mg; 50 Gy, 289 +/- 94 microg/mg; 100 Gy, 651 +/- 57 microg/mg. All implants still elicit an antibody immunoglobulin G reaction. Exposure to 10 Gy gamma irradiation reduces lymphocytic inflammatory infiltrates and Ca levels in acellular porcine matrices with preservation of structural integrity. This could prolong the durability of these matrices.

  1. Comparison of in vitro flows past a mechanical heart valve in anatomical and axisymmetric aorta models

    Science.gov (United States)

    Haya, Laura; Tavoularis, Stavros

    2017-06-01

    Flow characteristics past a bileaflet mechanical heart valve were measured under physiological flow conditions in a straight tube with an axisymmetric expansion, similar to vessels used in previous studies, and in an anatomical model of the aorta. We found that anatomical features, including the three-lobed sinus and the aorta's curvature affected significantly the flow characteristics. The turbulent and viscous stresses were presented and discussed as indicators for potential blood damage and thrombosis. Both types of stresses, averaged over the two axial measurement planes, were significantly lower in the anatomical model than in the axisymmetric one. This difference was attributed to the lower height-to-width ratio and more gradual contraction of the anatomical aortic sinus. The curvature of the aorta caused asymmetries in the velocity and stress distributions during forward flow. Secondary flows resulting from the aorta's curvature are thought to have redistributed the fluid stresses transversely, resulting in a more homogeneous stress distribution in the anatomical aortic root than in the axisymmetric root. The results of this study demonstrate the importance of modelling accurately the aortic geometry in experimental and computational studies of prosthetic devices. Moreover, our findings suggest that grafts used for aortic root replacement should approximate as closely as possible the shape of the natural sinuses.

  2. Simulations of pulsatile suspension flow through bileaflet mechanical heart valves to quantify platelet damage

    Science.gov (United States)

    Yun, Brian; Aidun, Cyrus; Yoganathan, Ajit

    2012-11-01

    Studies have shown that high shear stress and long exposure times on platelets have a strong impact on thromboembolic complications in bileaflet mechanical heart valves (BMHVs). This numerical study quantifies the platelet damage incurred in pulsatile flow through various BMHV designs. The lattice-Boltzmann method with external boundary force (LBM-EBF) was implemented to simulate pulsatile flow and capture the dynamics and surface shear stresses of modeled platelets with realistic geometry. The platelets are released in key regions of interest in the geometry as well as at various times of the cardiac cycle. The platelet damage is quantified using a linear shear stress-exposure time blood damage index (BDI) model. The multiscale computational method used to quantitatively measure the BDI during the pulsatile flow has been validated as being able to accurately capture bulk BMHV fluid flow and for accurately quantifying platelet damage in BMHV flows. These simulations will further knowledge of the geometric features and cardiac cycle times that most affect platelet damage. This study will ultimately lead to optimization of BMHV design in order to minimize thromboembolic complications.

  3. Low-Dose Gamma Irradiation of Decellularized Heart Valves Results in Tissue Injury In Vitro and In Vivo.

    Science.gov (United States)

    Helder, Meghana R K; Hennessy, Ryan S; Spoon, Daniel B; Tefft, Brandon J; Witt, Tyra A; Marler, Ronald J; Pislaru, Sorin V; Simari, Robert D; Stulak, John M; Lerman, Amir

    2016-02-01

    Decellularized heart valves are emerging as a potential alternative to current bioprostheses for valve replacement. Whereas techniques of decellularization have been thoroughly examined, terminal sterilization techniques have not received the same scrutiny. This study evaluated low-dose gamma irradiation as a sterilization method for decellularized heart valves. Incubation of valves and transmission electron microscopy evaluation after different doses of gamma irradiation were used to determine the optimal dose of gamma irradiation. Quantitative evaluation of mechanical properties was done by tensile mechanical testing of isolated cusps. Sterilized decellularized heart valves were tested in a sheep model (n = 3 [1 at 1,500 Gy and 2 at 3,000 Gy]) of pulmonary valve replacement. Valves sterilized with gamma radiation between 1,000 Gy and 3,000 Gy were found to be optimal with in vitro testing. However, in vivo testing showed deteriorating valve function within 2 months. On explant, the valve with 1,500 Gy gamma irradiation showed signs of endocarditis with neutrophils on hematoxylin and eosin staining, and positive gram stain resembling streptococcus infection. The 3,000 Gy valves had no evidence of infection, but the hematoxylin and eosin staining showed evidence of wound remodeling with macrophages and fibroblasts. Tensile strength testing showed decreased strength (0 Gy: 2.53 ± 0.98 MPa, 1,500 Gy: 2.03 ± 1.23 MPa, and 3,000 Gy: 1.26 ± 0.90 MPa) with increasing levels of irradiation. Low-dose gamma irradiation does not maintain the mechanical integrity of valves, and the balance between sterilization and damage may not be able to be achieved with gamma irradiation. Other methods of terminal sterilization must be pursued and evaluated. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  4. A novel left heart simulator for the multi-modality characterization of native mitral valve geometry and fluid mechanics.

    Science.gov (United States)

    Rabbah, Jean-Pierre; Saikrishnan, Neelakantan; Yoganathan, Ajit P

    2013-02-01

    Numerical models of the mitral valve have been used to elucidate mitral valve function and mechanics. These models have evolved from simple two-dimensional approximations to complex three-dimensional fully coupled fluid structure interaction models. However, to date these models lack direct one-to-one experimental validation. As computational solvers vary considerably, experimental benchmark data are critically important to ensure model accuracy. In this study, a novel left heart simulator was designed specifically for the validation of numerical mitral valve models. Several distinct experimental techniques were collectively performed to resolve mitral valve geometry and hemodynamics. In particular, micro-computed tomography was used to obtain accurate and high-resolution (39 μm voxel) native valvular anatomy, which included the mitral leaflets, chordae tendinae, and papillary muscles. Three-dimensional echocardiography was used to obtain systolic leaflet geometry. Stereoscopic digital particle image velocimetry provided all three components of fluid velocity through the mitral valve, resolved every 25 ms in the cardiac cycle. A strong central filling jet (V ~ 0.6 m/s) was observed during peak systole with minimal out-of-plane velocities. In addition, physiologic hemodynamic boundary conditions were defined and all data were synchronously acquired through a central trigger. Finally, the simulator is a precisely controlled environment, in which flow conditions and geometry can be systematically prescribed and resultant valvular function and hemodynamics assessed. Thus, this work represents the first comprehensive database of high fidelity experimental data, critical for extensive validation of mitral valve fluid structure interaction simulations.

  5. High-speed imaging of developing heart valves reveals interplay of morphogenesis and function.

    Science.gov (United States)

    Scherz, Paul J; Huisken, Jan; Sahai-Hernandez, Pankaj; Stainier, Didier Y R

    2008-03-01

    Knowing how mutations disrupt the interplay between atrioventricular valve (AVV) morphogenesis and function is crucial for understanding how congenital valve defects arise. Here, we use high-speed fluorescence microscopy to investigate AVV morphogenesis in zebrafish at cellular resolution. We find that valve leaflets form directly through a process of invagination, rather than first forming endocardial cushions. There are three phases of valve function in embryonic development. First, the atrioventricular canal (AVC) is closed by the mechanical action of the myocardium, rolls together and then relaxes. The growing valve leaflets serve to block the canal during the roll and, depending on the developmental stage, either expand or hang down as a leaflet to block the canal. These steps are disrupted by the subtle morphological changes that result from inhibiting ErbB-, TGFbeta-or Cox2 (Ptgs2)-dependent signaling. Cox2 inhibition affects valve development due to its effect on myocardial cell size and shape, which changes the morphology of the ventricle and alters valve geometry. Thus, different signaling pathways regulate distinct aspects of the behavior of individual cells during valve morphogenesis, thereby influencing specific facets of valve function.

  6. Harnessing osteopontin and other natural inhibitors to mitigate ectopic calcification of bioprosthetic heart valve material

    Science.gov (United States)

    Ohri, Rachit

    Dystrophic calcification has been the long-standing major cause of bioprosthetic heart valve failure, and has been well studied in terms of the underlying causative mechanisms. Such understanding has yielded several anti-calcification strategies involving biomaterial modification at the preparation stage: chemical alteration, extraction of calcifiable components, or material modification with small-molecule anti-calcific agents. However, newer therapeutic opportunities are offered by the growing illustration of the pathology as a dynamic, actively regulated process involving several gene products, such as osteopontin (OPN), matrix-gla protein (MGP) and glycosaminoglycans (GAGs). Osteopontin, a multi-functional matricellular glycosylated phosphoprotein has emerged as a prime candidate for the role of an in vivo inhibitor of ectopic calcification with two putative mechanisms: crystal poisoning and mineral-dissolution. The full therapeutic realization of its potential necessitates a better understanding of the mechanisms of anti-calcification by osteopontin, as well as appropriate in vivo models in which to evaluate its efficacy, potency and molecular mechanisms. In this work, we pursued the development and characterization of a reliable in vivo model with the OPN-null mouse to simulate the calcification of bioprosthetic valve material, namely glutaraldehyde-fixed bovine pericardium (GFBP) tissue. Subsequently, we used the calcification model to evaluate hypotheses based on the anti-calcific potential of osteopontin. Several modes of administering exogenous OPN to the implant site in OPN-null mice were explored, including soluble injected OPN, OPN covalently immobilized on the biomaterial, and OPN adsorbed onto the biomaterial. An investigation of the structure-function aspects of the anti-calcific ability of OPN was also pursued in the in vivo model. The OPN-null mouse was also used as an in vivo test-bed to evaluate the anti-calcific potential of other biomolecules

  7. Effect of Arched Leaflets and Stent Profile on the Hemodynamics of Tri-leaflet Flexible Polymeric Heart Valves

    Science.gov (United States)

    Yousefi, Atieh; Bark, David L.; Dasi, Lakshmi P.

    2016-01-01

    Polymeric heart valves (PHV) can be engineered to serve as alternatives for existing prosthetic valves due to higher durability and hemodynamics similar to bioprosthetic valves. The purpose of this study is to evaluate the effect of geometry on PHVs coaptation and hemodynamic performance. The two geometric factors considered are stent profile and leaflet arch length, which were varied across six valve configurations. Three models were created with height to diameter ratio of 0.6, 0.7, and 0.88. The other three models were designed by altering arch height to stent diameter ratio, to be 0, 0.081, and 0.116. Particle image velocimetry (PIV) experiments were conducted on each PHV to characterize velocity, vorticity, turbulent characteristics, effective orifice area (EOA), and regurgitant fraction. This study revealed that the presence of arches as well as higher stent profile reduced regurgitant flow down to 5%, while peak systole downstream velocity reduced to 58% and Reynolds Shear Stress values reduced 40%. Further, earlier reattachment of the forward flow jet was observed in PHVs with leaflet arches. These findings indicate that although both geometric factors help diminish the commissural gap during diastole, leaflet arches induce a larger jet opening, yielding to earlier flow reattachment and lower energy dissipation. PMID:27307007

  8. Mental health status of patients with mechanical aortic valves, with ventricular assist devices and after heart transplantation.

    Science.gov (United States)

    Heilmann, Claudia; Kaps, Josefine; Hartmann, Armin; Zeh, Wolfgang; Anjarwalla, Anna Lena; Beyersdorf, Friedhelm; Siepe, Matthias; Joos, Andreas

    2016-08-01

    Mental health is a complex construct, in which emotional aspects and quality of life are central. It has been assessed in patients after heart transplantation (HTX) and occasionally in those with ventricular assist devices (VADs). However, there are no studies that compare patients with primary HTX with those with HTX ending VAD support. Evidence for patients with mechanical aortic valve replacement is also limited. We compared mental outcome for these four groups for the first time. We also focused on the question of an artificial device, i.e. VAD or mechanical aortic valve, as distinct from a biological graft, i.e. HTX. Two questionnaires were applied: The Hospital Anxiety and Depression Scale, the German version consists of two subscales for anxiety and for depression, and the 12-item Short Form Health Survey, the German version contains two subscales for physical and for mental performance measuring quality of life. We included 46 patients with mechanical aortic valve replacement, 55 after HTX and 22 on support by a long-term VAD. The HTX group consisted of 38 patients with primary HTX and 17 recipients who were on VAD support before transplantation. The index operation was at least 6 months ago. HTX patients suffered less from anxiety and depression than patients with mechanical aortic valve replacement or those on VAD. HTX patients had higher scores on the physical scale but not on the mental component scale of the 12-item Short Form Health Survey compared with VAD patients. Conversely, patients with mechanical aortic valve replacement did worse with regard to mental but not physical performance compared with HTX patients. VAD and mechanical aortic valve replacement patients differed only with regard to physical condition, but not with regard to anxiety, depression and mental status. HTX patients with and without VAD support before transplantation achieved similar values on all scales. Mental scales did not correlate with age or time after surgery. HTX

  9. Evaluation of shear stress accumulation on blood components in normal and dysfunctional bileaflet mechanical heart valves using smoothed particle hydrodynamics.

    Science.gov (United States)

    Shahriari, S; Maleki, H; Hassan, I; Kadem, L

    2012-10-11

    Evaluating shear induced hemodynamic complications is one of the major concerns in design of the mechanical heart valves (MHVs). The monitoring of these events relies on both numerical simulations and experimental measurements. Currently, numerical approaches are mainly based on a combined Eulerian-Lagrangian approach. A more straightforward evaluation can be based on the Lagrangian analysis of the whole blood. As a consequence, Lagrangian meshfree methods are more adapted to such evaluation. In this study, smoothed particle hydrodynamics (SPH), a fully meshfree particle method originated to simulate compressible astrophysical flows, is applied to study the flow through a normal and a dysfunctional bileaflet mechanical heart valves (BMHVs). The SPH results are compared with the reference data. The accumulation of shear stress patterns on blood components illustrates the important role played by non-physiological flow patterns and mainly vortical structures in this issue. The statistical distribution of particles with respect to shear stress loading history provides important information regarding the relative number of blood components that can be damaged. This can be used as a measure of the response of blood components to the presence of the valve implant or any implantable medical device. This work presents the first attempt to simulate pulsatile flow through BMHVs using SPH method. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Comparison of the myocardial protective effect of sevoflurane versus propofol in patients undergoing heart valve replacement surgery with cardiopulmonary bypass.

    Science.gov (United States)

    Yang, Xiao-Lin; Wang, Dan; Zhang, Guo-Yuan; Guo, Xiao-Lan

    2017-03-04

    This study aimed to compare myocardial protective effects of anaesthesia with intravenous infusion of propofol versus inhalation of sevoflurane in patients undergoing heart valve replacement surgery with cardiopulmonary bypass. Seventy-six patients undergoing valve replacement with cardiopulmonary bypass were randomly assigned to propofol or sevoflurane anesthesia during the surgery, respectively. For assessing myocardial injury, cardiac troponin I (cTnI) and creatine kinase isozyme (CK-MB) were determined before induction (T0), 0.5 h (T1) and 3 h (T2) after aortic unclamping, and 24 h (T3) and 48 h (T4) after surgery. The concentrations of interleukin (IL)-6 and IL-10 as the systemic inflammatory and anti-inflammatory markers were also measured at above time points. In the sevoflurane group, the plasma concentrations of cTnI and CK-MB from Tl to T4 and the levels of IL-6 and IL-10 from T1 to T2 were lower than those in the propofol group. Moreover, a higher ratio of automatic heart beat recovery and a shorter length of intensive care unit or hospital stay were found in the sevoflurane group comparing with the propofol group. Sevoflurane anaesthesia produced more prominent myocardial protection and attenuated inflammatory response than propofol anaesthesia in patients with valve replacement surgery under cardiopulmonary bypass, resulting in shorter ICU and in-hospital stay. Identified as ChiCTR-IOR-16009979 at http://www.chictr.org.cn/ .

  11. Ectopic ossification with haematopoietic bone marrow in the heart valves of a crossbred heavy horse.

    Science.gov (United States)

    Matsuda, K; Tabata, S; Kawamura, Y; Kurosawa, T; Yoshie, N; Taniyama, H

    2010-01-01

    Ectopic bone formation in the left atrioventricular valves and cardiac fibroskeleton, with systemic circulatory disturbance, is reported in a 4-year-old crossbred heavy horse. Microscopically, there was fibrosis, chondral metaplasia and mature bone, with bone marrow within the left atrioventricular cusps and in the annuli of the aortic and right atrioventricular valves. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. Anticoagulation in pregnant women with mechanical heart valves : the new ESC guidelines

    NARCIS (Netherlands)

    Pieper, P. G.

    2012-01-01

    In pregnant women with a mechanical valve prosthesis, anticoagulation therapy is challenging because of the risk of embryopathy with vitamin K antagonists (VKA's), while unfractioned heparin and low molecular weight heparin (LMWH) are associated with a higher risk of valve thrombosis [1]. The

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

    Energy Technology Data Exchange (ETDEWEB)

    Schwitter, J. [Div. of Cardiology and Cardiovascular, MR Center, Univ. Hospital Zurich (Switzerland)

    2000-06-01

    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.) [German] Das diagnostische Repertoire zur Evaluation von Klappenvitien ist in den letzten Jahren

  14. Effect of metoprolol on heart rate variability in symptomatic patients with mitral valve prolapse.

    Science.gov (United States)

    Taçoy, Gülten; Balcioğlu, Akif Serhat; Arslan, Uğur; Durakoğlugil, Emre; Erdem, Güliz; Ozdemir, Murat; Cengel, Atiye

    2007-06-01

    Metoprolol is widely used to eliminate symptoms in patients with mitral valve prolapse (MVP), a condition associated with enhanced sympathetic tone. In this study, effects of metoprolol on heart rate variability (HRV) indices were investigated in symptomatic patients with MVP. Thirty-nine symptomatic patients with MVP (26 women, mean age 26 +/- 7 years) and 16 age- and gender-matched controls were studied. After a baseline 24-hour Holter evaluation in all subjects, patients with MVP were started on metoprolol succinate therapy at a dose of 25 to 100 mg/d, and Holter analysis was repeated at the end of 3 months of metoprolol therapy. At the basal evaluation, all time-domain HRV indices with the exception of proportion of adjacent RR intervals differing by >50 ms in the 24-hour recording were significantly lower in patients with MVP than controls (SD of all normal-to-normal [NN] intervals, p = 0.013; SD of average NN intervals calculated during 5-minute periods of the entire recording, p = 0.03; triangular index, p = 0.025; and square root of mean squared differences in successive NN intervals, p = 0.026). After metoprolol treatment, all HRV indices significantly improved compared with baseline (SD of all NN intervals, p = 0.028; SD of average NN intervals calculated during 5-minute periods of the entire recording, p = 0.043; triangular index, p = 0.004; square root of the mean squared differences in successive NN intervals, p = 0.021; and proportion of adjacent RR intervals differing by >50 ms in the 24-hour recording, p = 0.014), and HRV indices after metoprolol treatment were similar to those of the control group (p >0.05). In conclusion, metoprolol significantly improved impaired HRV parameters in symptomatic patients with MVP.

  15. Textile heart valve prosthesis: from fabric design criteria to early in-vivo performances.

    Science.gov (United States)

    Heim, Frederic; Durand, Bernard; Chafke, Nabil

    2013-05-01

    Percutaneous aortic valve implantation has become an alternative technique to surgical valve replacement in patients at high risk for open-chest surgery. Biological valve tissue is, however, a fragile material when folded for small-diameter catheter insertion purposes. Textile polyester is a less fragile material, and could be an alternative replacement for the valve leaflets. The dynamic performances obtained in vitro with a valve prosthesis made from textile have proven in previous studies to be satisfactory. However, as textile is a porous material the interaction processes between the fabric leaflet surfaces and living tissues remain unknown. The study aim was to discuss the fabric design criteria which are best suited to clinical application. An appropriate design provided strength, limited porosity and low bulk to the fabric, which was particularly suited for small-diameter catheter insertion purposes. The in-vivo behavior of a non-coated polyester textile valve prototype was then studied in the mitral position in a sheep model. The results showed that limited tissue ingrowth occurred, and Ca deposits tended to stiffen the fabric leaflets after a two-month implantation period, which was not compatible with the survival of the animal. The initial results obtained with this non-coated polyester textile valve confirmed that this revolutionary fabric is worthy of further investigation.

  16. The Impact of Obesity on Postoperative Outcomes in Adults with Congenital Heart Disease Undergoing Pulmonary Valve Replacement.

    Science.gov (United States)

    Buelow, Matthew W; Earing, Michael G; Hill, Garick D; Cohen, Scott B; Bartz, Peter J; Tweddell, James S; Ginde, Salil

    2015-01-01

    The impact of obesity on surgical morbidity in adults with congenital heart disease is currently unknown. The aim of our study was to investigate the impact of obesity on postoperative outcomes in adults with congenital heart disease undergoing reoperation for pulmonary valve replacement. A retrospective analysis was performed assessing the influence of obesity on surgical outcomes. Obesity was defined as a body mass index ≥30 kg/m2. The mean body mass index of the cohort was 25.9 ± 6.9 kg/m2 . The cohort included 71 patients with 17 patients (24%) being obese. There was no postoperative mortality. Obese patients had a longer hospital length of stay (6.6 vs. 4.7 days; P 5 days (odds ratio [OR] = 5.2; 95% confidence interval [CI]: 1.5-18.2, P = .01) and with increased postoperative arrhythmias (OR = 4.2; 95% CI: 1.7-40, P congenital heart disease undergoing pulmonary valve replacement, including longer hospitalization and higher risk for postoperative arrhythmias. © 2015 Wiley Periodicals, Inc.

  17. First percutaneous implantation of a completely tissue-engineered self-expanding pulmonary heart valve prosthesis using a newly developed delivery system: a feasibility study in sheep.

    Science.gov (United States)

    Spriestersbach, Hendrik; Prudlo, Antonia; Bartosch, Marco; Sanders, Bart; Radtke, Torben; Baaijens, Frank P T; Hoerstrup, Simon P; Berger, Felix; Schmitt, Boris

    2017-01-01

    In a European consortium, a decellularized tissue-engineered heart valve (dTEHV) based on vessel-derived cells, a fast-degrading scaffold and a self-expanding stent has been developed. The aim of this study was to demonstrate that percutaneous delivery is feasible. To implant this valve prosthesis transcutaneously into pulmonary position, a catheter delivery system was designed and custom made. Three sheep underwent transjugular prototype implantation. Intracardiac echocardiography (ICE), angiography and computed tomography (CT) were applied to assess the position, morphology, function and dimensions of the stented dTEHV. One animal was killed 3 h after implantation and two animals were followed up for 12 weeks. Explanted valves were analyzed macroscopically and microscopically. In all animals, the percutaneous implantation of the stented dTEHV was successful. The prototype delivery system worked at first attempt in all animals. In the first implantation a 22 F system was used: the valve was slightly damaged during crimping. Loading was difficult due to valve-catheter mismatch in volume. In the second and third implantation a 26 F system was used: the valves fitted adequately and stayed intact. Following implantation, these two valves showed moderate regurgitation due to insufficient coaptation. During follow-up, regurgitation increased due to shortened leaflets. At explantation, macroscopic and microscopic analysis confirmed the second and third valve to be intact. Histology revealed autologous recellularization of the decellularized valve after 12 weeks in vivo. It was demonstrated that completely in vitro tissue-engineered heart valves are thin and stable enough to be crimped and implanted transvenously into pulmonary position.

  18. Fluid structure interaction (FSI) simulation of bileaflet mechanical heart valve in an anatomic aorta geometry

    Science.gov (United States)

    Ge, Liang; Borazjani, Iman; Dasi, Lakshmi; Sotiropoulos, Fotis; Yoganathan, Ajit

    2007-11-01

    FSI simulation of a medical quality BMHV implanted in the aortic position is studied. The valve is implanted in an anatomic non-compliant aorta geometry, which is reconstructed from MRI data acquired from a healthy volunteer. A physiological incoming flow waveform is specified at the inlet with the peak systolic Reynolds number equal to 6000. The flow solver is based on the CURVIB (curvilinear immersed boundary method) of Ge and Sotiropoulos, 2007 (JCP) and the FSI problem is solved with strong coupling partitioned approach. Direct numerical simulation is carried out on a grid system consisting of 10M grid nodes. The impact on hemodynamics by valve implantation is studied by considering different valve implantation angles. The calculated numerical results are analyzed in terms of leaflet kinematics and flow physics, and compared with data from our previous work, where the same valve is implanted in a simplified straight aorta geometry.

  19. Heart murmurs

    Science.gov (United States)

    Chest sounds - murmurs; Heart sounds - abnormal; Murmur - innocent; Innocent murmur; Systolic heart murmur; Diastolic heart murmur ... The heart has 4 chambers: Two upper chambers (atria) Two lower chambers (ventricles) The heart has valves that close ...

  20. Pilot licensing after aortic valve surgery.

    Science.gov (United States)

    Syburra, Thomas; Schnüriger, Hans; Kwiatkowski, Barbara; Graves, Kirk; Reuthebuch, Oliver; Genoni, Michele

    2010-05-01

    Bicuspid aortic valve is the most common congenital heart malformation, and a high percentage of patients with this condition will develop complications over time. It is rare that pilots undergo aortic valve surgery, and the confirmation of flight-licensing requirements after aortic valve replacement (AVR) is a challenge for the patient's cardiac surgeon and, particularly, for the Aeromedical Examiner (AME). Only AMEs are able to determine the flight status of pilots. Furthermore, in military and in civil aviation (e.g., Red Bull Air Race), the high G-load environment experienced by pilots is an exceptional physiological parameter, which must be considered postoperatively. A review was conducted of the aeronautical, surgical and medical literature, and of European pilot-licensing regulations. Case studies are also reported for two Swiss Air Force pilots. According to European legislation, pilots can return to flight duty from the sixth postoperative month, with the following limitations: that an aortic bioprosthesis presents no restrictions in cardiac function, requires no cardioactive medications, yet requires a flight operation with co-pilot, the avoidance of accelerations over +3 Gz and, in military aviation, restricts the pilot to non-ejection-seat aircraft. The patient follow up must include both echocardiographic and rhythm assessments every six months. Mechanical prostheses cannot be certified because the required anticoagulation therapy is a disqualifying condition for pilot licensing. Pilot licensing after aortic valve surgery is possible, but with restrictions. The +Gz exposition is of concern in both military and civilian aviation (aerobatics). The choice of bioprosthesis type and size is determinant. Pericardial and stentless valves seem to show better flow characteristics under high-output conditions. Repetitive cardiological controls are mandatory for the early assessment of structural valve disease and rhythm disturbances. A pre-emptive timing is

  1. Two- and three-dimensional transoesophageal echocardiography in large swine used as model for transcatheter heart valve therapies: standard planes and values.

    Science.gov (United States)

    Sündermann, Simon H; Cesarovic, Nikola; Falk, Volkmar; Bettex, Dominique

    2016-05-01

    Swine models are widely used to develop new techniques and materials for the treatment of heart valve disease like aortic valve and mitral valve transcatheter interventions and to train physicians in these techniques. Transoesophageal echocardiography (TOE) is crucial in these models. We defined standard planes of 2D and 3D TOE in healthy pigs undergoing transcatheter heart valve interventions. Twenty healthy pigs (weight 56-106 kg) underwent different mitral and aortic valve interventions (transcatheter aortic valve implantations, implantations of a mitral band, bicuspidization of the aortic valve, trans-septal punctures). For image guidance of the procedures, an adult TOE probe was introduced under direct vision in the oesophagus. Before the procedure itself was performed, a standardized protocol was used to determine normal values for anatomical and functional echocardiographic parameters. Positioning of the probe was possible in all animals and ideal when achieving a distance from the front teeth (incisors) of 40-60 cm. Anteflexion and lateroflexion of the probe was necessary to achieve optimal imaging quality. 2D visualization of all relevant cardiac structures was possible. The aortic annulus diameter was 24.1 ± 2.5 mm, the sinus of valsalva diameter was 30.6 ± 4 mm and the sinotubular junction diameter was 25.2 ± 4 mm. The ascending aorta had a diameter of 24 ± 4 mm and the descending aorta a diameter of 16 ± 5 mm. The mitral valve anterior-posterior diameter was 31.8 ± 4 mm and the commissure to commissure diameter was 40.5 ± 5 mm resulting in a mitral valve area of 10.7 ± 1.5 cm(2). 3D visualization was possible for the aortic and the mitral valve. None of the animals showed any pathology except one that had a dilated left ventricle and moderate mitral valve insufficiency. Left and right ventricular dimensions and the anatomy of the aortic-, mitral-, tricuspid and pulmonary valve as well as of the aorta were comparable with those of the human

  2. Outcomes and Prognostic Factors for Adult Patients With Congenital Heart Disease Undergoing Primary or Reoperative Systemic Atrioventricular Valve Surgery.

    Science.gov (United States)

    Stephens, Elizabeth H; Han, Jiho; Ginns, Jonathan; Rosenbaum, Marlon; Chai, Paul; Bacha, Emile; Kalfa, David

    2017-05-01

    Adults with congenital heart disease (ACHD) undergoing systemic atrioventricular valve (SAVV) surgery are a complex, understudied population. We assessed midterm outcomes and prognostic factors in ACHD undergoing SAVV surgery. We performed retrospective evaluation of ACHD undergoing SAVV surgery from January 2005 to February 2016: 14 (33%) patients with congenital mitral valve stenosis/regurgitation, 15 (35%) with atrioventricular septal defect (AVSD), and 14 (33%) with congenitally corrected transposition of the great arteries (ccTGA) with systemic tricuspid valve regurgitation. Adverse events were defined as mortality, reoperation on SAVV, and late more-than-moderate (> moderate) SAVV regurgitation. Statistical analysis was performed using Fisher's exact test and one-way analysis of variance as well as univariate and multivariate risk factor analysis. Fifteen (35%) patients had preoperative systemic ventricular dysfunction, including 13 patients with ccTGA (93%, P moderate SAVV regurgitation, and SAVV reoperation rates were 5% (n = 2), 2% (n = 1), 9% (n = 3), and 7% (n = 3), respectively. On multivariate analysis, predischarge SAVV regurgitation grade was the only significant predictor of adverse events (odds ratio = 8.2, 95% confidence interval: 1.1-63.8, P = .045). Overall outcomes in this challenging population are good. The single factor associated with adverse events was predischarge SAVV regurgitation grade.

  3. Numerical study of the influence of the hinge gap width on the hinge flow fields of bileaflet mechanical heart valves

    Science.gov (United States)

    Simon, Helene; Ge, Liang; Sotiropoulos, Fotis; Yoganathan, Ajit

    2008-11-01

    Previous clinical and in-vitro studies have shown that the complex non-physiologic hemodynamics occurring in the hinge region of bileaflet mechanical heart valves promotes blood cell damage and thrombus formation. Modifying the hinge design could improve the flow and thus reduce the associated blood cell trauma. This study aims at investigating numerically the effect of the hinge gap width on the flow field. The governing equations are solved using a Cartesian sharp interface immersed boundary method coupled with a hybrid staggered/non staggered control volume approach. The hinge dimensions are obtained from MicroComputed Tomography of a clinical valve. The leaflet motion and inlet velocity profile are imposed based on the Fluid-Structure Interaction simulations of the bulk flow of a valve placed under aortic physiologic conditions. 3D pulsatile flows through two hinge designs are presented along with their Lagrangian analysis. The hinge gap width is shown to have a strong influence on the flow, and thus on blood cell trauma.

  4. Cardioprotection of Electroacupuncture for Enhanced Recovery after Surgery on Patients Undergoing Heart Valve Replacement with Cardiopulmonary Bypass: A Randomized Control Clinical Trial

    Directory of Open Access Journals (Sweden)

    Fangxiang Zhang

    2017-01-01

    Full Text Available We attempted to investigate cardioprotection of electroacupuncture (EA for enhanced recovery after surgery on patients undergoing heart valve replacement with cardiopulmonary bypass. Forty-four patients with acquired heart valve replacement were randomly allocated to the EA group or the control group. Patients in the EA group received EA stimulus at bilateral Neiguan (PC6, Ximen (PC4, Shenting (GV24, and Baihui (GV20 acupoints twenty minutes before anesthesia induction to the end of surgery. The primary end point was cardioprotection effect of electroacupuncture postoperatively and the secondary endpoints were quality of recovery and cognitive functioning postoperatively. The present study demonstrated that electroacupuncture reduced the occurrence of complications and played a role of cardioprotective effect on patients after heart valve replacement surgery with cardiopulmonary bypass, and it benefits patients more comfortable and contributes to recovery after surgery. This trial is registered with ChiCTR-IOC-16009123.

  5. 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

  6. Stress state during fixation determines susceptibility to fatigue-linked biodegradation in bioprosthetic heart valve materials.

    Science.gov (United States)

    Margueratt, Sean D; Lee, J Michael

    2002-01-01

    Mechanical loading contributes to the structural deterioration of bioprosthetic heart valves. The influence of stress state during fixation may play a substantial role in their failure, linking fatigue damage caused by buckling and tension and the enzymatic degradation of glutaraldehyde-crosslinked collagen. Bovine pericardia were obtained immediately postmortem and 100 mm x 15 mm samples were cut in the base-to-apex direction. Half the samples were subjected to a uniaxial tensile stress of 250 kPa and half remained unloaded during a crosslinking treatment in 0.5% glutaraldehyde. Tissue samples were rinsed and cut into 16 mm x 4 mm test strips. Half of these strips were exposed to cyclic compressive buckling and alternating tension at 30 Hz for 20 million cycles (approx. 7.5 days) using a custom-built multi-sample fatigue system. Fatigue-damaged and non-damaged samples were subsequently incubated at 37 C for 48 hrs in: (i) Type I bacterial collagenase (20 U/ml) buffered in 0.05 M Tris, 10 mM CaCl2 2H2O (pH 7.4) or (ii) 0.05 M Tris buffer (pH 7.4) only. In both cases, the samples were loaded sinusoidally between 40 and 80 g using a previously described microtensile culture system. Tissue removed from the bath was rinsed in 0.1 M EDTA solution and mounted in a servo-hydraulic mechanical testing system (MTS). Ultimate tensile strength (UTS), maximum tissue modulus, and fracture strain were determined. The percent collagen solubilized was assessed by a colourmetric hydroxyproline assay of the enzyme bath and tissue sample. All data were analyzed by analysis of variance (ANOVA). The results confirmed the synergy between fatigue damage and collagenase proteolysis in these materials; however, there were no significant differences in this effect between simple fixation and stress-fixation up to 20 million cycles. There were significant decreases in the mechanical properties and an increase in the amount of collagen solubilized with increased exposure to fatigue cycling.

  7. Anticoagulation for pregnant women with mechanical heart valves: a systematic review and meta-analysis.

    Science.gov (United States)

    D'Souza, Rohan; Ostro, Jackie; Shah, Prakesh S; Silversides, Candice K; Malinowski, Ann; Murphy, Kellie E; Sermer, Mathew; Shehata, Nadine

    2017-05-14

    To review maternal and foetal outcomes in women with mechanical heart valves (MHVs) treated with vitamin-K antagonists (VKAs), first-trimester heparin followed by VKAs (sequential treatment), low molecular weight heparin (LMWH) and unfractionated heparin (UFH) during pregnancy, in order to inform practice. Medline, Embase and Central were searched from inception until February 2016. Two reviewers independently screened 1786 titles, reviewed 110 full-texts and extracted data and assessed risk-of-bias from 46 articles. Pooled incidence (95% confidence intervals) was calculated for maternal and foetal outcomes. Included studies had a moderate or high risk-of-bias. With VKAs, sequential treatment and LMWH, maternal mortality occurred in 0.9% (0.4-1.4), 2.0% (0.8-3.1) and 2.9% (0.2-5.7), thromboembolic complications in 2.7% (1.4-4.0), 5.8% (3.8-7.7) and 8.7% (3.9-13.4), livebirths in 64.5% (48.8-80.2), 79.9% (74.3-85.6) and 92.0% (86.1-98.0) and anticoagulant-related foetal/neonatal adverse events (embryopathy or foetopathy) in 2.0% (0.3-3.7), 1.4% (0.3-2.5) and 0%, respectively. When UFH is used throughout pregnancy, 11.2% (2.8-19.6) suffered thromboembolic complications. Foetal loss and adverse events occurred with first-trimester warfarin doses ≤ 5 mg/day, although there were more livebirths [83.6% (75.8-91.4) vs. 43.9% (32.8-55.0)] and fewer foetal anomalies [2.3% (0.7-4.0) vs. 12.4% (3.3-21.6)] with lower doses than with warfarin > 5 mg/day. VKAs are associated with fewest maternal complications but also with fewest livebirths. Sequential treatment does not eliminate anticoagulant-related foetal/neonatal adverse events. LMWH is associated with the highest number of livebirths. The safety of UFH throughout pregnancy and first-trimester warfarin  ≤ 5 mg/day remains unconfirmed.

  8. Biomechanical properties of hybrid heart valve prosthesis utilizing the pigs that do not express the galactose-α-1,3-galactose (α-Gal) antigen derived tissue and tissue engineering technique.

    Science.gov (United States)

    Wilczek, Piotr; Lesiak, Anna; Niemiec-Cyganek, Aleksandra; Kubin, Barbara; Slomski, Ryszard; Nozynski, Jerzy; Wilczek, Grazyna; Mzyk, Aldona; Gramatyka, Michalina

    2015-01-01

    The aim of the study was to estimate the biomechanical properties of heart valves conduit derived from transgenic pigs to determine the usefulness for the preparation of tissue-engineered heart valves. The acellular aortic and pulmonary valve conduits from transgenic pigs were used to estimate the biomechanical properties of the valve. Non-transgenic porcine heart valve conduits were used as a reference. The biomechanics stability of acellular valve conduits decreased both for the transgenic and non-transgenic porcine valves. The energy required to break the native pulmonary valve derived from transgenic pigs was higher (20,475 ± 7,600 J m(-2)) compared with native non-transgenic pigs (12,140 ± 5,370 J m(-2)). After acellularization, the energy to break the valves decreased to 14,600 and 8,800 J m(-2) for the transgenic pulmonary valve and non-transgenic valve, respectively. The native transgenic pulmonary valve showed a higher extensibility (42.70 %) than the non-transgenic pulmonary valve (35.50 %); the extensibility decreased after acellularization to 41.1 and 31.5 % for the transgenic and non-transgenic valves, respectively. The pulmonary valves derived from transgenic pigs demonstrate better biomechanical properties compared with non-transgenic. Heart valves derived from transgenic pigs can be valuable for the preparation of tissue-engineered bioprostheses, because of their biomechanical properties, stability, reduced immune response, making them safer for clinical applications.

  9. Comparison of hinge microflow fields of bileaflet mechanical heart valves implanted in different sinus shape and downstream geometry.

    Science.gov (United States)

    Kuan, Yee Han; Kabinejadian, Foad; Nguyen, Vinh-Tan; Su, Boyang; Yoganathan, Ajit P; Leo, Hwa Liang

    2015-01-01

    The characterization of the bileaflet mechanical heart valves (BMHVs) hinge microflow fields is a crucial step in heart valve engineering. Earlier in vitro studies of BMHV hinge flow at the aorta position in idealized straight pipes have shown that the aortic sinus shapes and sizes may have a direct impact on hinge microflow fields. In this paper, we used a numerical study to look at how different aortic sinus shapes, the downstream aortic arch geometry, and the location of the hinge recess can influence the flow fields in the hinge regions. Two geometric models for sinus were investigated: a simplified axisymmetric sinus and an idealized three-sinus aortic root model, with two different downstream geometries: a straight pipe and a simplified curved aortic arch. The flow fields of a 29-mm St Jude Medical BMHV with its four hinges were investigated. The simulations were performed throughout the entire cardiac cycle. At peak systole, recirculating flows were observed in curved downsteam aortic arch unlike in straight downstream pipe. Highly complex three-dimensional leakage flow through the hinge gap was observed in the simulation results during early diastole with the highest velocity at 4.7 m/s, whose intensity decreased toward late diastole. Also, elevated wall shear stresses were observed in the ventricular regions of the hinge recess with the highest recorded at 1.65 kPa. Different flow patterns were observed between the hinge regions in straight pipe and curved aortic arch models. We compared the four hinge regions at peak systole in an aortic arch downstream model and found that each individual hinge did not vary much in terms of the leakage flow rate through the valves.

  10. Differences in collagen cross-linking between the four valves of the bovine heart: a possible role in adaptation to mechanical fatigue.

    Science.gov (United States)

    Aldous, Ian G; Veres, Samuel P; Jahangir, Alireza; Lee, J Michael

    2009-06-01

    Hydrothermal isometric tension (HIT) testing and high-performance liquid chromatography were used to assess the molecular stability and cross-link population of collagen in the four valves of the adult bovine heart. Untreated and NaBH(4)-treated tissues under isometric tension were heated in a water bath to a 90 degrees C isotherm that was sustained for 5 h. The denaturation temperature (T(d)), associated with hydrogen bond rupture and molecular stability, and the half-time of load decay (t(1/2)), associated with peptide bond hydrolysis and intermolecular cross-linking, were calculated from acquired load/temperature/time data. An unpaired group of samples of the same population was biochemically assayed for the types and quantities of enzymatic cross-links present. Tissues known to endure higher in vivo transvalvular pressures had lower T(d) values, suggesting that molecular stability is inversely related to in vivo loading. The treated inflow valves (mitral and tricuspid) had significantly lower t(1/2) values than did treated outflow valves (aortic and pulmonary), suggesting lower overall cross-linking in the inflow valves. Inflow valves were also found to fail during HIT testing significantly more often than outflow valves, also suggestive of a decreased cross-link population. Inflow valves may be remodeling at a faster rate and may be at an earlier state of molecular "maturity" than outflow valves. At the molecular level, the thermal stability of collagen is associated with in vivo loading and may be influenced by the mature, aldimine-derived cross-link, histidinohydroxylysinonorleucine. We conclude that the valves of the heart utilize differing, location-specific strategies to resist biomechanical fatigue loading.

  11. Management of tricuspid valve regurgitation: Position statement of the European Society of Cardiology Working Groups of Cardiovascular Surgery and Valvular Heart Disease.

    Science.gov (United States)

    Antunes, Manuel J; Rodríguez-Palomares, José; Prendergast, Bernard; De Bonis, Michele; Rosenhek, Raphael; Al-Attar, Nawwar; Barili, Fabio; Casselman, Filip; Folliguet, Thierry; Iung, Bernard; Lancellotti, Patrizio; Muneretto, Claudio; Obadia, Jean-François; Pierard, Luc; Suwalski, Piotr; Zamorano, Pepe

    2017-12-01

    Tricuspid regurgitation (TR) is a very frequent manifestation of valvular heart disease. It may be due to the primary involvement of the valve or secondary to pulmonary hypertension or to the left-sided heart valve disease (most commonly rheumatic and involving the mitral valve). The pathophysiology of secondary TR is complex and is intrinsically connected to the anatomy and function of the right ventricle. A systematic multimodality approach to diagnosis and assessment (based not only on the severity of the TR but also on the assessment of annular size, RV function and degree of pulmonary hypertension) is, therefore, essential. Once considered non-important, treatment of secondary TR is currently viewed as an essential concomitant procedure at the time of mitral (and, less frequently, aortic valve) surgery. Although the indications for surgical management of severe TR are now generally accepted (Class I), controversy persists concerning the role of intervention for moderate TR. However, there is a trend for intervention in this setting, especially at the time of surgery for left-sided heart valve disease and/or in patients with significant tricuspid annular dilatation (Class IIa). Currently, surgery remains the best approach for the interventional treatment of TR. Percutaneous tricuspid valve intervention (both repair and replacement) is still in its infancy but may become a reliable option in future, especially for high-risk patients with isolated primary TR or with secondary TR related to advanced left-sided heart valve disease. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  12. Our new tornado-compatible aortic valve prosthesis: notable results of hydrodynamic testing and experimental trials

    Directory of Open Access Journals (Sweden)

    Leo A. Bockeria

    2014-05-01

    Full Text Available Aims A shortcoming common to all existing designs of mechanical cardiac valve prostheses is an increased trombogenicity caused, among other factors, by the lack of hydrodynamic compatibility between the luminal part of the prosthesis and the patterned blood flow. The aim of the study is to design and test our new mechanical aortic valve prosthesis to exclude life-long anticoagulation treatment. Materials and methods Standard hydrodynamic tests of the new prosthetic valve have been carried out for comparing with the other existing valve designs. A new method for the heart valve prosthesis testing in a tornado-like flow has been developed. The valve function has been verified in a swine excluding the anticoagulation treatment during the period of time exceeding six months. Results The significant advantage of the new prosthesis in the standard hydrodynamic tests has been demonstrated. The tests in the tornado-like flow have shown that only this prosthesis allows maintaining the pattern, the head and flow rate characteristics of the tornado-like jet. Upon implanting the new prosthesis in the aortic position in a swine, the good performance of the valve without anticoagulation therapy has been confirmed in the course of more than six months. Conclusion Obtained has been the evidence of the merits of the new mechanical aortic valve owing to the due consideration of the hydrodynamic peculiarities of the aortic blood flow and the creation of the design providing the proper hydrodynamic compatibility.

  13. How Heart Valves Evolve to Adapt to an Extreme-Pressure System

    DEFF Research Database (Denmark)

    Amstrup Funder, Jonas; Christian Danielsen, Carl; Baandrup, Ulrik

    2017-01-01

    by failure tests. Thickness measurements and analyses of elastin and collagen content were also made. Valve specimens were stained with hematoxylin and eosin, elastic van Gieson stain, Masson's trichrome and Fraser-Lendrum stain, as well as immunohistochemical reactions for morphological examinations...

  14. Dynamic three-dimensional phase-contrast technique in MRI: application to complex flow analysis around the artificial heart valve

    Science.gov (United States)

    Kim, Soo Jeong; Lee, Dong Hyuk; Song, Inchang; Kim, Nam Gook; Park, Jae-Hyeung; Kim, JongHyo; Han, Man Chung; Min, Byong Goo

    1998-07-01

    Phase-contrast (PC) method of magnetic resonance imaging (MRI) has bee used for quantitative measurements of flow velocity and volume flow rate. It is a noninvasive technique which provides an accurate two-dimensional velocity image. Moreover, Phase Contrast Cine magnetic resonance imaging combines the flow dependent contrast of PC-MRI with the ability of cardiac cine imaging to produce images throughout the cardiac cycle. However, the accuracy of the data acquired from the single through-plane velocity encoding can be reduced by the effect of flow direction, because in many practical cases flow directions are not uniform throughout the whole region of interest. In this study, we present dynamic three-dimensional velocity vector mapping method using PC-MRI which can visualize the complex flow pattern through 3D volume rendered images displayed dynamically. The direction of velocity mapping can be selected along any three orthogonal axes. By vector summation, the three maps can be combined to form a velocity vector map that determines the velocity regardless of the flow direction. At the same time, Cine method is used to observe the dynamic change of flow. We performed a phantom study to evaluate the accuracy of the suggested PC-MRI in continuous and pulsatile flow measurement. Pulsatile flow wave form is generated by the ventricular assistant device (VAD), HEMO-PULSA (Biomedlab, Seoul, Korea). We varied flow velocity, pulsatile flow wave form, and pulsing rate. The PC-MRI-derived velocities were compared with Doppler-derived results. The velocities of the two measurements showed a significant linear correlation. Dynamic three-dimensional velocity vector mapping was carried out for two cases. First, we applied to the flow analysis around the artificial heart valve in a flat phantom. We could observe the flow pattern around the valve through the 3-dimensional cine image. Next, it is applied to the complex flow inside the polymer sac that is used as ventricle in

  15. Protocol for Relative Hydrodynamic Assessment of Tri-leaflet Polymer Valves

    Science.gov (United States)

    Ramaswamy, Sharan; Salinas, Manuel; Carrol, Rob; Landaburo, Karla; Ryans, Xavier; Crespo, Cynthia; Rivero, Ailyn; Al-Mousily, Faris; DeGroff, Curt; Bleiweis, Mark; Yamaguchi, Hitomi

    2013-01-01

    Limitations of currently available prosthetic valves, xenografts, and homografts have prompted a recent resurgence of developments in the area of tri-leaflet polymer valve prostheses. However, identification of a protocol for initial assessment of polymer valve hydrodynamic functionality is paramount during the early stages of the design process. Traditional in vitro pulse duplicator systems are not configured to accommodate flexible tri-leaflet materials; in addition, assessment of polymer valve functionality needs to be made in a relative context to native and prosthetic heart valves under identical test conditions so that variability in measurements from different instruments can be avoided. Accordingly, we conducted hydrodynamic assessment of i) native (n = 4, mean diameter, D = 20 mm), ii) bi-leaflet mechanical (n= 2, D = 23 mm) and iii) polymer valves (n = 5, D = 22 mm) via the use of a commercially available pulse duplicator system (ViVitro Labs Inc, Victoria, BC) that was modified to accommodate tri-leaflet valve geometries. Tri-leaflet silicone valves developed at the University of Florida comprised the polymer valve group. A mixture in the ratio of 35:65 glycerin to water was used to mimic blood physical properties. Instantaneous flow rate was measured at the interface of the left ventricle and aortic units while pressure was recorded at the ventricular and aortic positions. Bi-leaflet and native valve data from the literature was used to validate flow and pressure readings. The following hydrodynamic metrics were reported: forward flow pressure drop, aortic root mean square forward flow rate, aortic closing, leakage and regurgitant volume, transaortic closing, leakage, and total energy losses. Representative results indicated that hydrodynamic metrics from the three valve groups could be successfully obtained by incorporating a custom-built assembly into a commercially available pulse duplicator system and subsequently, objectively compared to provide

  16. Appropriateness criteria for the use of cardiovascular imaging in heart valve disease in adults: A European Association of Cardiovascular Imaging report of literature review and current practice

    NARCIS (Netherlands)

    Chambers, J.B. (John B.); M. Garbi (Madalina); K. Nieman (Koen); Myerson, S. (Saul); L. Pié rard (Luc); G. Habib (Gilbert); J.L. Zamorano (Jose); H. Edvardsen (Hege); P. Lancellotti (Patrizio); V. Delgado (Victoria); J. Cosyns; E. Donal (Erwan); R. Dulgheru (Raluca); M. Galderisi (Maurizio); Lombardi, M. (Massimo); Muraru, D. (Denisa); Kauffmann, P. (Philipp); N. Cardim (Nuno); Haugaa, K. (Kristina); R. Rosenhek (Raphael)

    2017-01-01

    textabstractHeart valve disease is common and a major indication for imaging. Echocardiography is the first-line imaging technique for diagnosis, assessment, and serial surveillance. However, other modalities, notably cardiac magnetic resonance imaging and computerized tomography, are used if

  17. Preseeding of human vascular cells in decellularized bovine pericardium scaffold for tissue-engineered heart valve : An in vitro and in vivo feasibility study

    NARCIS (Netherlands)

    Yang, Min; Chen, Chang-Zhi; Shu, Yu-Sheng; Shi, Wei-Ping; Cheng, Shao-Fei; Gu, Y. John

    Human vascular cells from saphenous veins have been used for cell seeding on the synthetic scaffolds for constructing tissue-engineered heart valve (TEHV). However, little is known about the seeding of human vascular cells on bovine pericardium, a potential natural scaffold for TEHV. This study was

  18. The impact of a new model-based iterative reconstruction algorithm on prosthetic heart valve related artifacts at reduced radiation dose MDCT

    NARCIS (Netherlands)

    Suchá, Dominika; Willemink, Martin J.; de Jong, Pim A.; Schilham, Arnold M. R.; Leiner, Tim; Symersky, Petr; Budde, Ricardo P. J.

    2014-01-01

    To assess the impact of hybrid iterative reconstruction (IR) and novel model-based iterative reconstruction (IMR) and dose reduction on prosthetic heart valve (PHV) related artifacts and objective image quality. One transcatheter and two mechanical PHVs were embedded in diluted contrast-gel,

  19. 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

  20. Mitral valve surgery in a patient with dextrocardia and 180° counter-clockwise rotated heart due to congenital agenesis of the right lung.

    Science.gov (United States)

    Atsumi, Yosuke; Tokunaga, Shigehiko; Yasuda, Shota; Fushimi, Kenichi; Masuda, Munetaka

    2013-11-01

    We report a case of severe mitral regurgitation (MR) with dextrocardia and 180° counterclockwise rotated situs solitus heart. We describe the technique for mitral valve surgery in a patient with dextrocardia and agenesis of the right lung. © 2013 Wiley Periodicals, Inc.

  1. Mitral Valve Prolapse

    Science.gov (United States)

    ... State SELECT YOUR LANGUAGE Español (Spanish) 简体中文 (Traditional Chinese) 繁体中文 (Simplified Chinese) Tiếng Việt (Vietnamese) Healthy Living for Heart.org ... valve syndrome . What happens during MVP? Watch an animation of mitral valve prolapse When the heart pumps ( ...

  2. The dynamic function of the atrial diastole of the heart and motion of venous valves in humans.

    Science.gov (United States)

    Rai, Dinker B

    2013-03-01

    This study demonstrates dynamic function of atrial diastole for the first time in the history of medicine, following the revelation of ventricular function by Sir William Harvey. This study consists of two parts. First part is the study of humans and the discovery of the rhythmic opening and closing of venous valves in the femoral vein segment during each cardiac cycle under fluoroscopy. Its relationship to the right atrial diastole is discussed. Second part is an experimental model developed in a dog's heart. Experiments are conducted in an erect posture, in which the right atrium is partially and totally isolated physically and/or functionally. The right atrium was found to function as a suction pump, readily demonstrated on graphic curves by voluntary stretching of muscle fibers of the empty atrium, creating considerable negative pressure during diastolic function, and responsible for venous return to the heart. Motive forces in the venous return are common knowledge in present medical literature, but are limited to respiration and skeletal muscle contraction of the extremities. The discovery of the right atrium as a suction force due to stretching of muscle fibers during diastolic function, thereby creating negative pressure, represents a departure from the currently accepted paradigm established by Sir William Harvey (1576-1652), with the heart as an organ functioning solely by contraction of its chambers. This is the first time since then a fundamental new discovery concerning cardiac mechanical function has been made utilizing experimental evidence.

  3. Heart-rate adjustment of transcatheter haemodynamics improves the prognostic evaluation of paravalvular regurgitation after transcatheter aortic valve implantation.

    Science.gov (United States)

    Jilaihawi, Hasan; Chakravarty, Tarun; Shiota, Takahiro; Rafique, Asim; Harada, Kenji; Shibayama, Kentaro; Doctor, Niraj; Kashif, Mohammad; Nakamura, Mamoo; Mirocha, James; Rami, Tejas; Okuyama, Kazuaki; Cheng, Wen; Sadruddin, Omar; Siegel, Robert; Makkar, Raj R

    2015-08-01

    Paravalvular aortic regurgitation (PVAR) after balloon-expandable transcatheter aortic valve implantation (TAVI) remains difficult to quantify, and the utility of the AR index (ARi) to create a composite aortic insufficiency (CAI) score was an important advance. Heart rate (HR) influences the ARi but the clinical relevance of this phenomenon remains poorly appreciated. We sought to validate a new composite heart-rate-adjusted haemodynamic-echocardiographic aortic insufficiency (CHAI) score in the prognostic evaluation of PVAR after balloon-expandable TAVI. The severity of PVAR was assessed immediately post TAVI by transoesophageal echocardiography (TOE) with simultaneous assessment of transcatheter haemodynamics. A total of 303 patients were studied. The CHAI score, incorporating the HR-adjusted diastolic-delta (HRA-DD, the difference between left ventricular and aortic diastolic pressures/HR*80), had a greater discriminatory value for one-year mortality than both PVAR by TOE (p=0.0018) and the previously proposed CAI score, based on the ARi without HR adjustment (p=0.0029). The CHAI score also better stratified percentage increases in left ventricular systolic chamber dimensions at one month and serum natriuretic peptide levels at one to three months. Prognostication of PVAR in the intermediate range of echocardiographic severity remains unreliable and is greatly enhanced by the integration of heart-rate-adjusted transcatheter haemodynamics.

  4. Legionella cardiaca sp. nov., isolated from a case of native valve endocarditis in a human heart.

    Science.gov (United States)

    Pearce, Meghan M; Theodoropoulos, Nicole; Mandel, Mark J; Brown, Ellen; Reed, Kurt D; Cianciotto, Nicholas P

    2012-12-01

    A Gram-negative, rod-shaped bacterium, designated H63(T), was isolated from aortic valve tissue of a patient with native valve endocarditis. 16S rRNA gene sequencing revealed that H63(T) belongs to the genus Legionella, with its closest neighbours being the type strains of Legionella brunensis (98.8% similarity), L. londiniensis (97.0%), L. jordanis (96.8%), L. erythra (96.2%), L. dresdenensis (96.0%) and L. rubrilucens, L. feeleii, L. pneumophila and L. birminghamensis (95.7%). DNA-DNA hybridization studies yielded values of cardiaca sp. nov. is proposed. The type strain is H63(T) ( = ATCC BAA-2315(T)  = DSM 25049(T)  = JCM 17854(T)).

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

    Science.gov (United States)

    Annerel, Sebastiaan; Degroote, Joris; Claessens, Tom; Vierendeels, Jan

    2010-06-01

    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.

  6. The potential of prolonged tissue culture to reduce stress generation and retraction in engineered heart valve tissues.

    Science.gov (United States)

    van Vlimmeren, Marijke A A; Driessen-Mol, Anita; Oomens, Cees W J; Baaijens, Frank P T

    2013-03-01

    In tissue-engineered (TE) heart valves, cell-mediated processes cause tissue compaction during culture and leaflet retraction at time of implantation. We have quantified and correlated stress generation, compaction, retraction, and tissue quality during a prolonged culture period of 8 weeks. Polyglycolic acid/poly-4-hydroxybutyrate strips were seeded with vascular-derived cells and cultured for 4-8 weeks. Compaction in width, generated force, and stress was measured during culture. Retraction in length, generated force, and stress was measured after release of constraints at weeks 4, 6, and 8. Further, the amount of DNA, glycosaminoglycans (GAGs), collagen, and collagen cross-links was assessed. During culture, compaction and force generation increased to, respectively, 63.9% ± 0.8% and 43.7 ± 4.3 mN at week 4, after which they remained stable. Stress generation reached 27.7 ± 3.2 kPa at week 4, after which it decreased to ∼8.5 kPa. At release of constraints, tissue retraction was 44.0% ± 3.7% at week 4 and decreased to 29.2% ± 2.8% and 26.1% ± 2.2% at, respectively, 6 and 8 weeks. Generated force (8-16 mN) was lower at week 6 than at weeks 4 and 8. Generated stress decreased from 11.8 ± 0.9 kPa at week 4 to 1.4 ± 0.3 and 2.4 ± 0.4 kPa at, respectively, weeks 6 and 8. The amount of GAGs increased at weeks 6 and 8 compared to week 4 and correlated to the reduced stress and retraction. In summary, prolonged culture resulted in decreased stress generation and retraction, likely as a result of the increased amount of GAGs. These results demonstrate the potential of prolonged tissue culture in developing functional, nonretracting, TE heart valves.

  7. Minimally invasive fibrillating heart surgery: a safe and effective approach for mitral valve and surgical ablation for atrial fibrillation.

    Science.gov (United States)

    Massimiano, Paul S; Yanagawa, Bobby; Henry, Linda; Holmes, Sari D; Pritchard, Graciela; Ad, Niv

    2013-08-01

    Minimally invasive (MI) approaches to mitral valve surgery (MVS) and surgical ablation for atrial fibrillation (AF) are now performed routinely, and avoidance of aortic manipulation and cardioplegic arrest may further simplify the procedure. We present our experience with MI fibrillatory cardiac operations without aortic cross-clamping for MVS and AF ablation. Between January 2007 and August 2012, 292 consecutive patients underwent MVS (n = 177), surgical ablation (n = 81), or both (n= 34), with fibrillating heart through a right minithoracotomy. Baseline characteristics, perioperative outcomes, and long-term survival were evaluated. The mean age was 56.8 years (range, 20-83 years). Reoperations were performed in 25 patients (9%). The overall MV repair rate was 93.4% (198/211), including 13.1% (26/198) with anterior leaflet repair. Repair was performed in 100% of patients with myxomatous MV disease. Of isolated posterior mitral valve repairs, 60.5% underwent repair with neochords (W.L. Gore and Associates, Flagstaff, AZ), and 29.7% underwent triangular resection. There was 1 operative mortality (0.3%), no intraoperative conversions to sternotomy, 4 reoperations (1.4%), 1 stroke (0.3%), and 1 transient ischemic attack (0.3%). The 12-month return to sinus rhythm was 93%, and sinus rhythm without class I and class III antiarrhythmic medication was 85%. One- and 2-year cumulative survival was 98.5% and 97.8%, respectively. At mean follow-up of 27.3 months, our outcomes compared favorably with the 2011 Society of Thoracic Surgeons (STS) nationally reported outcomes. We demonstrated that low operative mortality and low stroke rate with MI fibrillating cardiac operations without cross-clamping allows for MVS and AF ablation. Our results suggest that the MI fibrillating heart approach is safe and effective. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Comparison of four risk scores for in-hospital mortality in patients undergoing heart valve surgery: A multicenter study in a Chinese population.

    Science.gov (United States)

    Wang, Chong; Tang, Yang-Feng; Zhang, Jia-Jun; Bai, Yi-Fan; Yu, Yong-Chao; Zhang, Guan-Xin; Han, Lin

    2016-01-01

    To compare four risk scores with regard to their validity to predict in-hospital mortality after heart valve surgery in a multicenter patient population of China. From January 2009 to December 2012, data from 12,412 consecutive patients older than 16 years who underwent heart valve surgery at four cardiac surgical centers were collected and scored according to the EuroSCORE II, Ambler risk score, NYC risk score, and STS risk score. The patients were divided into two subgroups according to the types of valve procedures, and the performance of the four risk scores for each group was assessed. Calibration was assessed by the Hosmer-Lemeshow (H-L) test. Discrimination was tested by calculating the area under the receiver operating characteristic (ROC) curve. Observed mortality was 2.09% overall. The EuroSCORE II, Ambler score, and NYC score overpredicted observed mortality (Hosmer-Lemeshow: P = 0.002, P surgery compared with the Ambler score and NYC score. However, all four risk scores give an imprecise prediction in patients undergoing multiple valve surgery. Both the STS score and Euroscore II, especially the STS score, were suitable for individual operative risk in Chinese patients undergoing single valve surgery compared with the Ambler score and NYC score, however, all four risk scores were not suitable for prediction in Chinese patients undergoing multiple valve surgery. Therefore, the creation of a new model which accurately predicts outcomes in patients undergoing multiple valve surgery is possibly required in China. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  9. Maternal and Fetal Outcomes of Anticoagulation in Pregnant Women With Mechanical Heart Valves.

    Science.gov (United States)

    Steinberg, Zachary L; Dominguez-Islas, Clara P; Otto, Catherine M; Stout, Karen K; Krieger, Eric V

    2017-06-06

    Anticoagulation for mechanical heart valves during pregnancy is essential to prevent thromboembolic events. Each regimen has drawbacks with regard to maternal or fetal risk. This meta-analysis sought to estimate and compare the risk of adverse maternal and fetal outcomes in pregnant women with mechanical heart valves who received different methods of anticoagulation. Studies were identified using a Medline search including all publications up to June 5, 2016. Study inclusion required reporting of maternal death, thromboembolism, and valve