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Sample records for bioprosthetic heart valves

  1. 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.

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

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    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 

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

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    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

  4. Transcatheter valve-in-valve implantation for failed bioprosthetic heart valves.

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    Webb, John G; Wood, David A; Ye, Jian; Gurvitch, Ronen; Masson, Jean-Bernard; Rodés-Cabau, Josep; Osten, Mark; Horlick, Eric; Wendler, O; Dumont, Eric; Carere, Ronald G; Wijesinghe, Namal; Nietlispach, Fabian; Johnson, Mark; Thompson, Chrisopher R; Moss, Robert; Leipsic, Jonathon; Munt, Brad; Lichtenstein, Samuel V; Cheung, Anson

    2010-04-27

    The majority of prosthetic heart valves currently implanted are tissue valves that can be expected to degenerate with time and eventually fail. Repeat cardiac surgery to replace these valves is associated with significant morbidity and mortality. Transcatheter heart valve implantation within a failed bioprosthesis, a "valve-in-valve" procedure, may offer a less invasive alternative. Valve-in-valve implantations were performed in 24 high-risk patients. Failed valves were aortic (n=10), mitral (n=7), pulmonary (n=6), or tricuspid (n=1) bioprostheses. Implantation was successful with immediate restoration of satisfactory valve function in all but 1 patient. No patient had more than mild regurgitation after implantation. No patients died during the procedure. Thirty-day mortality was 4.2%. Mortality was related primarily to learning-curve issues early in this high-risk experience. At baseline, 88% of patients were in New York Heart Association functional class III or IV; at the last follow-up, 88% of patients were in class I or II. At a median follow-up of 135 days (interquartile range, 46 to 254 days) and a maximum follow-up of 1045 days, 91.7% of patients remained alive with satisfactory valve function. Transcatheter valve-in-valve implantation is a reproducible option for the management of bioprosthetic valve failure. Aortic, pulmonary, mitral, and tricuspid tissue valves were amenable to this approach. This finding may have important implications with regard to valve replacement in high-risk patients.

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

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    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.

  6. Characterization of immunogenic Neu5Gc in bioprosthetic heart valves.

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    Reuven, Eliran Moshe; Leviatan Ben-Arye, Shani; Marshanski, Tal; Breimer, Michael E; Yu, Hai; Fellah-Hebia, Imen; Roussel, Jean-Christian; Costa, Cristina; Galiñanes, Manuel; Mañez, Rafael; Le Tourneau, Thierry; Soulillou, Jean-Paul; Cozzi, Emanuele; Chen, Xi; Padler-Karavani, Vered

    2016-09-01

    The two common sialic acids (Sias) in mammals are N-acetylneuraminic acid (Neu5Ac) and its hydroxylated form N-glycolylneuraminic acid (Neu5Gc). Unlike most mammals, humans cannot synthesize Neu5Gc that is considered foreign and recognized by circulating antibodies. Thus, Neu5Gc is a potential xenogenic carbohydrate antigen in bioprosthetic heart valves (BHV) that tend to deteriorate in time within human patients. We investigated Neu5Gc expression in non-engineered animal-derived cardiac tissues and in clinically used commercial BHV, and evaluated Neu5Gc immunogenicity on BHV through recognition by human anti-Neu5Gc IgG. Neu5Gc was detected by immunohistochemistry in porcine aortic valves and in porcine and bovine pericardium. Qualitative analysis of Sia linkages revealed Siaα2-3>Siaα2-6 on porcine/bovine pericardium while the opposite in porcine aortic/pulmonary valve cusps. Similarly, six commercial BHV containing either porcine aortic valve or porcine/bovine/equine pericardium revealed Siaα2-3>Siaα2-6 expression. Quantitative analysis of Sia by HPLC showed porcine/bovine pericardium express 4-fold higher Neu5Gc levels compared to the porcine aortic/pulmonary valves, with Neu5Ac at 6-fold over Neu5Gc. Likewise, Neu5Gc was expressed on commercial BHV (186.3±16.9 pmol Sia/μg protein), with Neu5Ac at 8-fold over Neu5Gc. Affinity-purified human anti-Neu5Gc IgG showing high specificity toward Neu5Gc-glycans (with no binding to Neu5Ac-glycans) on a glycan microarray, strongly bound to all tested commercial BHV, demonstrating Neu5Gc immune recognition in cardiac xenografts. We conclusively demonstrated Neu5Gc expression in native cardiac tissues, as well as in six commercial BHV. These Neu5Gc xeno-antigens were recognized by human anti-Neu5Gc IgG, supporting their immunogenicity. Altogether, these findings suggest BHV-Neu5Gc/anti-Neu5Gc may play a role in valve deterioration warranting further investigation. © 2016 John Wiley & Sons A/S. Published by John Wiley

  7. A rare case report of early bioprosthetic valve thrombosis presenting with acute heart failure salvaged by thrombectomy.

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    Fan, Jingya; Teng, Peng; Zou, Yu; Ma, Liang

    2017-03-27

    Bioprosthetic valve thrombosis is previously considered as an extremely rare complication which hasn't been systemically recognized and understood. Herein, we present an unusual case of a patient manifesting with acute heart failure, secondary to thrombus formation in a porcine aortic bioprosthesis which was implanted 11 months prior to hospitalization. Due to the patient's poor heart function and intraoperative findings, thrombectomy was performed. For our best knowledge, cases of early bioprosthetic valve thrombosis presenting with acute heart failure have seldomly been reported. Our study reviews predisposing factors, typical echocardiographic features and treatment for bioprosthetic valve thrombosis and it should be considered as a reason for bioprosthetic malfunction. A combination of clinical and echocardiographic features can help for diagnosis preoperatively. In some certain circumstances, early reoperation can be avoided if anticoagulant therapy works.

  8. Bioprosthetic tricuspid valve replacement in carcinoid heart disease from primary ovarian carcinoid tumor.

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    Tsugu, Toshimitsu; Iwanaga, Shiro; Murata, Mitsushige; Fukuda, Keiichi

    2015-07-01

    Carcinoid heart disease (CHD) commonly occurs in association with primary gastrointestinal tract carcinoid tumors with hepatic metastases. Unlike primary gastrointestinal tract carcinoid tumors, primary ovarian carcinoid tumors may cause CHD without hepatic metastases, accounting for only 0.3 % of all carcinoid tumors. Only 37 cases of CHD from primary ovarian carcinoid tumors have been reported. We present a case of CHD in which tricuspid valve thickening and shortening led to reduced valve mobility with the resulting severe tricuspid regurgitation. Considering these characteristics of an abnormal tricuspid valve, we suspected CHD, but prosthetic valve replacement was performed without sufficient systemic examination before surgery. Two years after valve replacement, the patient underwent excision of a mass in the lower abdomen, which was diagnosed as an ovarian carcinoid tumor by histopathological examination. The patient has been observed for more than 3 years after tricuspid valve replacement. She has not experienced bioprosthetic valve leaflet degeneration or dysfunction, although it has been reported that bioprosthetic valves may degenerate in patients with carcinoid tumors. Sufficient systemic examinations should be performed to explore the cause of disease.

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

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    Siddharth Wartak

    2016-01-01

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

  10. Biomechanical Behavior of Bioprosthetic Heart Valve Heterograft Tissues: Characterization, Simulation, and Performance

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    Soares, Joao S.; Feaver, Kristen R.; Zhang, Will; Kamensky, David; Aggarwal, Ankush; Sacks, Michael S.

    2017-01-01

    The use of replacement heart valves continues to grow due to the increased prevalence of valvular heart disease resulting from an ageing population. Since bioprosthetic heart valves (BHVs) continue to be the preferred replacement valve, there continues to be a strong need to develop better and more reliable BHVs through and improved the general understanding of BHV failure mechanisms. The major technological hurdle for the lifespan of the BHV implant continues to be the durability of the constituent leaflet biomaterials, which if improved can lead to substantial clinical impact. In order to develop improved solutions for BHV biomaterials, it is critical to have a better understanding of the inherent biomechanical behaviors of the leaflet biomaterials, including chemical treatment technologies, the impact of repetitive mechanical loading, and the inherent failure modes. This review seeks to provide a comprehensive overview of these issues, with a focus on developing insight on the mechanisms of BHV function and failure. Additionally, this review provides a detailed summary of the computational biomechanical simulations that have been used to inform and develop a higher level of understanding of BHV tissues and their failure modes. Collectively, this information should serve as a tool not only to infer reliable and dependable prosthesis function, but also to instigate and facilitate the design of future bioprosthetic valves and clinically impact cardiology. PMID:27507280

  11. Mechanical versus bioprosthetic aortic valve replacement.

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

    2017-07-21

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

  12. In vitro comparative assessment of decellularized bovine pericardial patches and commercial bioprosthetic heart valves.

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    Aguiari, Paola; Iop, Laura; Favaretto, Francesca; Fidalgo, Cátia Marisa Lourenco; Naso, Filippo; Milan, Gabriella; Vindigni, Vincenzo; Spina, Michel; Bassetto, Franco; Bagno, Andrea; Vettor, Roberto; Gerosa, Gino

    2017-02-03

    Notwithstanding their wide exploitation, biological prosthetic heart valves are characterized by limited durability (10-15 years). The treatment of biological tissues with chemical crosslinking agents such as glutaraldehyde accounts for the enhanced risk of structural deterioration associated with the early failure of bioprosthetic valves. To overcome the shortcomings of the currently available solutions, adoption of decellularized biological tissues of animal origin has emerged as a promising approach. The present study aims to assess in vitro cardiovascular scaffolds composed of bovine pericardium decellularized with the novel TRITDOC (TRIton-X100 and TauroDeOxyCholic acid) procedure. The effects of the treatment have been assessed by means of histological, biomolecular, cellular, biochemical and biomechanical analyses. The TRITDOC procedure grants the complete decellularization of bovine pericardial scaffolds while preserving the extracellular matrix architecture and the biomechanical properties. With a dedicated ELISA test, the TRITDOC procedure has been proven to ensure the complete removal of the alphaGal antigen, responsible for hyperacute rejection and for long-term deterioration of xenogenic biomaterials. Static seeding of the acellular pericardial patches with human adipose-derived stem cells resulted in an evenly repopulated scaffold without signs of calcification. The in vitro cyto-/immuno-compatibility response of the TRITDOC-bovine pericardium was compared with glutaraldehyde-treated xenogenic pericardium collected from two bioprosthetic devices currently used in clinical practice: PERIMOUNT MAGNA and TRIFECTA TM . TRITDOC-bovine pericardium exhibited lower complement activation, lower cytotoxicity and a lower tendency to secrete pro-inflammatory cytokines compared to the tested commercial bioprostheses. Therefore, TRITDOC-decellularized pericardium could be considered as possible candidate material for the production of prosthetic heart valves.

  13. In-vitro hemodynamics of stented bioprosthetic heart valves in the tilted implantation position.

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    Babin-Ebell, Joerg; Sievers, Hans H; Misfeld, Martin; Runge, Maike; Vogt, Paul Robert; Scharfschwerdt, Michael

    2008-09-01

    Although, in small aortic annulus or aortic annulus calcification, it is recommended that valves are implanted in a tilted position, mechanical valves show impaired hemodynamic performance when positioned in this way. To date, no investigations have been conducted with biological valves implanted in a tilted position. Measurements were performed in a pulsatile flow simulator. The aortic roots were mounted in a fluid reservoir and tested with bioprosthetic valves implanted in the regular position (21 mm; n = 7) or at a 200 tilt (23 mm; n = 7). Additional 21 mm valves were implanted in both positions with a systemic pressure of 120/80 mmHg. Subsequently, the valves were implanted into a glass model and flow visualization monitored by adding air bubbles illuminated with a laser diode. The 21 mm valves showed a slightly higher transvalvular gradient in the tilted than in the regular position, while 23 mm valves in a tilted position showed a lower gradient than 21 mm valves in the regular position. Flow in the regular position was seen to be straight and central, but in the tilted position was diverted and impacted on the aortic wall. Vortex formation in the tilted position was more pronounced than in the regular position, with certain low-flow areas being observed. The implantation of a one size-larger bioprosthetic valve at a 20 degree tilt in a small aortic root resulted in a slight reduction in transvalvular gradient compared to a smaller valve implanted in the regular position. Whilst mechanical valve performance is markedly compromised in the tilted position, the bioprosthetic valve showed only minor impairment of transvalvular pressure gradient due to tilting, and this was overcompensated by the larger valve size. However, the advantage of a greater orifice area must be traded against the consequences of the observed flow disturbances.

  14. Immune response in patients receiving a bioprosthetic heart valve: lack of response with decellularized valves.

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    Bloch, Oliver; Golde, Pia; Dohmen, Pascal M; Posner, Steffen; Konertz, Wolfgang; Erdbrügger, Wilhelm

    2011-10-01

    Conventional biological heart valves treated with glutaraldehyde (GA) reveal a limited lifespan due to calcification. This is assumed to be an immune response initiated process, which is not seen with decellularized valves. However, their immunological potential is still a matter of debate. Therefore, serum samples from patients undergoing heart valve surgery were obtained before (Pre), after (Post), and 9-12 months after operation (Follow Up). Immunoglobulin G (IgG) and M (IgM) antibodies against porcine collagen I and α-Gal (Gal-alpha1,3-Gal-beta1,4-GlcNac-R) were determined for decellularized and GA treated valves. Antibody titers for collagen type I revealed no significant alteration for both types of valves. However, a considerable anti-α-Gal antibody response was observed in patients with GA-treated porcine valves. In detail, IgM antibodies were increased during follow up (pvalves revealed a minor decrease in the IgM response (pvalves. This indicates that GA treatment is not sufficient to eliminate immune response to the α-Gal epitope completely. Future investigations will have to verify whether immune response to α-Gal can be linked to the limited durability of conventional valves. © Mary Ann Liebert, Inc.

  15. Harnessing osteopontin and other natural inhibitors to mitigate ectopic calcification of bioprosthetic heart valve material

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    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

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

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    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

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

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    Barbarash O

    2015-03-01

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

  18. Mechanical and surgical bioprosthetic valve thrombosis.

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    Lim, Wei Yao; Lloyd, Guy; Bhattacharyya, Sanjeev

    2017-12-01

    Valve thrombosis can occur in mechanical prosthetic valves and is increasingly recognised in transcatheter and surgically implanted bioprosthetic valves. The risk of thrombosis of mechanical valves is higher in the mitral position compared with aortic position and in older generation valves (ball and cage valves). There is a wide spectrum of presentation from the asymptomatic patient to those with embolic complications or cardiogenic shock. A combination of transthoracic and transesophageal echocardiography is required to assess the haemodynamic effect of thrombosis (valve gradients and area), leaflet motion and thrombus size. CT or cinefluoroscopy may be useful in selected cases to assess leaflet motion or help identify the aetiology of valve obstruction where echocardiography is inconclusive. Exclusion of pannus or vegetation is important. Management of non-obstructive thrombus is primarily optimisation of anti-coagulation. Treatment of obstructive thrombus requires a decision between slow, low-dose fibrinolysis or valve surgery. Factors which need to be considered include thrombus size, New York Heart Association Class, presence of concomitant coronary artery disease or other valve dysfunction, surgical risk and contraindication to fibrinolysis. This review examines the incidence, aetiology, clinical features, imaging algorithms and management of prosthetic valve thrombosis. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Midterm outcomes of mechanical versus bioprosthetic valve replacement in middle-aged patients: An Indian scenario

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    Dheeraj Sharma

    2017-01-01

    Conclusions: Bioprosthetic heart valves seem to be more beneficial in the Indian scenario as compared to mechanical valves because of low incidence of mortality and valve-related events and better quality of life.

  20. PORCINE VENA CAVA AS AN ALTERNATIVE TO BOVINE PERICARDIUM IN BIOPROSTHETIC PERCUTANEOUS HEART VALVES

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

    2011-01-01

    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 enhance leaflet flexibility, tissue resilience, and tissue

  1. Transcatheter heart valve in valve implantation with Edwards SAPIEN bioprosthetic valve for different degenerated bioprosthetic valve positions (First Iranian ViV report with mid-term follow up

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    Ali Mohammad Haji Zeinali

    2017-09-01

    Conclusion: As the first Iranian all-comers case series with midterm follow up for ViV implantation, we had no mortality. Interestingly none of our patients had neurologic sequelae after the procedure. Midterm follow up for our patients was acceptable with good functional class and appropriate echocardiographic findings. Due to high surgical risk of the redo procedure after failing of a bioprosthetic valve especially in elderly patients with comorbidities, ViV implantation would be a good alternative to surgery for this high risk group.

  2. Clinical Bioprosthetic Heart Valve Thrombosis After Transcatheter Aortic Valve Replacement: Incidence, Characteristics, and Treatment Outcomes.

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    Jose, John; Sulimov, Dmitriy S; El-Mawardy, Mohamed; Sato, Takao; Allali, Abdelhakim; Holy, Erik W; Becker, Björn; Landt, Martin; Kebernik, Julia; Schwarz, Bettina; Richardt, Gert; Abdel-Wahab, Mohamed

    2017-04-10

    The aim of this study was to determine the incidence, characteristics, and treatment outcomes of patients diagnosed with clinical transcatheter heart valve thrombosis. Limited data exists on clinical or manifest transcatheter heart valve thrombosis. Prior studies have focused on subclinical thrombosis. A retrospective analysis was conducted of prospectively collected data from a single-center registry that included 642 consecutive patients who underwent transcatheter aortic valve replacement between 2007 and 2015 (305 patients had self-expanding valves; balloon-expandable, n = 281; mechanically expanding, n = 56). Long-term oral anticoagulation (OAC) was indicated in 261 patients, while 377 patients received dual-antiplatelet therapy post-procedure. All patients underwent scheduled clinical and echocardiographic follow-up. The overall incidence of clinical valve thrombosis was 2.8% (n = 18). No patient on OAC developed thrombosis. Of the detected thrombosis cases, 13 patients had balloon-expandable, 3 had self-expanding, and 2 had mechanically expanding valves. Thrombosis occurred significantly more often with balloon-expandable valves (odds ratio: 3.45; 95% confidence interval: 1.22 to 9.81; p = 0.01) and following valve-in-valve procedures (odds ratio: 5.93; 95% confidence interval: 2.01 to 17.51; p = 0.005). Median time to diagnosis of valve thrombosis was 181 days. The median N-terminal pro-brain natriuretic peptide level was 1,318 pg/ml (interquartile range: 606 to 1,676 pg/ml). The mean transvalvular gradient and valve area were 34 ± 14 mm Hg and 1.0 ± 0.46 cm 2 , respectively. Computed tomography showed hypoattenuating areas with reduced leaflet motion. Initiation of OAC resulted in significant reduction of transvalvular gradient and clinical improvement. No deaths were related to valve thrombosis. Clinical transcatheter heart valve thrombosis is more common than previously considered, characterized by imaging abnormalities and increased gradients

  3. Degenerative processes in bioprosthetic mitral valves in juvenile pigs

    Directory of Open Access Journals (Sweden)

    Pedersen Torben B

    2011-05-01

    Full Text Available Abstract Background Glutaraldehyde-treated bioprosthetic heart valves are commonly used for replacement of diseased heart valves. However, calcification and wear limit their durability, and the development of new and improved bioprosthetic valve designs is needed and must be evaluated in a reliable animal model. We studied glutaraldehyde-treated valves 6 months after implantation to evaluate bioprosthetic valve complications in the mitral position in juvenile pigs. Materials The study material comprised eight, 5-month old, 60-kg pigs. All pigs received a size 27, glutaraldehyde-treated, stented, Carpentier-Edwards S.A.V. mitral valve prosthesis. After six months, echocardiography was performed, and the valves explanted for gross examination, high resolution X-ray, and histological evaluation. Results Five pigs survived the follow-up period. Preexplant echocardiography revealed a median peak and mean velocity of 1.61 m/s (range: 1.17-2.00 and 1.20 (SD = ±0.25, respectively, and a median peak and mean pressure difference of 10.42 mmHg (range: 5.83-16.55 and 6.51 mmHg (SD = ±2.57, respectively. Gross examination showed minor thrombotic depositions at two commissures in two valves and at all three commissures in three valves. High resolution X-ray imaging revealed different degrees of calcification in all explanted valves, primarily in the commissural and belly areas. In all valves, histological evaluation demonstrated various degrees of fibrous sheath formation, limited immunological infiltration, and no overgrowth of host endothelium. Conclusions Bioprosthetic glutaraldehyde-treated mitral valves can be implanted into the mitral position in pigs and function after 6 months. Echocardiographic data, calcification, and histological examinations were comparable to results obtained in sheep models and human demonstrating the suitability of the porcine model.

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

    Science.gov (United States)

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

    2015-06-01

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

  5. Percutaneous Valvuloplasty for Bioprosthetic Tricuspid Valve Stenosis.

    Science.gov (United States)

    Rana, Gaurav; Malhotra, Rohit; Sharma, Anjali; Kakouros, Nikolaos

    2017-02-01

    Percutaneous transcatheter tricuspid balloon valvuloplasty (PTTBV) is an accepted treatment option for symptomatic severe native tricuspid valve stenosis, although surgical tricuspid valve replacement remains the treatment of choice. There have been few reports of successful PTTBV for bioprosthetic tricuspid valve stenosis. We present case reports of 3 patients from our hospital experience. Two of the 3 cases were successful, with lasting clinical improvement, whereas the 3rd patient failed to show a reduction in valve gradient. We describe the standard technique used for PTTBV. We present results from a literature review that identified 16 previously reported cases of PTTBV for bioprosthetic severe tricuspid stenosis, with overall favorable results. We conclude that PTTBV should perhaps be considered for a select patient population in which symptomatic improvement and hemodynamic stability are desired immediately, and particularly for patients who are inoperable or at high surgical risk.

  6. Antithrombotic therapy after bioprosthetic aortic valve implantation

    DEFF Research Database (Denmark)

    Rafiq, Sulman; Steinbrüchel, Daniel Andreas; Lilleør, Nikolaj Bang

    2017-01-01

    Background The optimal medical strategy for prevention of thromboembolic events after surgical bioprosthetic aortic valve replacement (BAVR) is still debated. The objective of this study was to compare warfarin therapy (target INR of 2.0 to 3.0) with aspirin 150 mg daily as antithrombotic therapy...... for the first three months after BAVR with or without concomitant coronary artery bypass grafting (CABG). The aim was to evaluate thromboembolic complications, major bleeding complications and death. Materials and methods Prospective, single-centre, open-label, randomized controlled trial. 370 patients were...

  7. Transcatheter Tricuspid Valve-in-Valve Intervention for Degenerative Bioprosthetic Tricuspid Valve Disease.

    Science.gov (United States)

    Praz, Fabien; George, Isaac; Kodali, Susheel; Koulogiannis, Konstantinos P; Gillam, Linda D; Bechis, Mary Z; Rubenson, David; Li, Wei; Duncan, Alison

    2017-08-23

    Isolated reoperative tricuspid valve replacement is one of the highest risk operations classified in the Society of Thoracic Surgeons registry, particularly in the setting of preexisting right ventricular dysfunction. Transcatheter tricuspid valve-in-valve implantation represents an attractive alternative to redo surgery in patients with tricuspid bioprosthetic valve degeneration who are considered high-risk or unsuitable surgical candidates. In this review article, the authors discuss the emergence of transcatheter tricuspid valve-in-valve therapy, preprocedural echocardiographic assessment of tricuspid bioprosthetic valve dysfunction, periprocedural imaging required for tricuspid valve-in-valve implantation, and postprocedural assessment of tricuspid transcatheter device function. Copyright © 2017 American Society of Echocardiography. All rights reserved.

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    Preetham R Muskula

    2017-04-01

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

  10. Indentation hardness: A simple test that correlates with the dissipated-energy predictor for fatigue-life in bovine pericardium membranes for bioprosthetic heart valves.

    Science.gov (United States)

    Tobaruela, Almudena; Rojo, Francisco Javier; García Paez, José María; Bourges, Jean Yves; Herrero, Eduardo Jorge; Millán, Isabel; Alvarez, Lourdes; Cordon, Ángeles; Guinea, Gustavo V

    2016-08-01

    The aim of this study was to evaluate the variation of hardness with fatigue in calf pericardium, a biomaterial commonly used in bioprosthetic heart valves, and its relationship with the energy dissipated during the first fatigue cycle that has been shown to be a predictor of fatigue-life (García Páez et al., 2006, 2007; Rojo et al., 2010). Fatigue tests were performed in vitro on 24 pericardium specimens cut in a root-to-apex direction. The specimens were subjected to a maximum stress of 1MPa in blocks of 10, 25, 50, 100, 250, 500, 1000 and 1500 cycles. By means of a modified Shore A hardness test procedure, the hardness of the specimen was measured before and after fatigue tests. Results showed a significant correlation of such hardness with fatigue performance and with the energy dissipated in the first cycle of fatigue, a predictor of pericardium durability. The study showed indentation hardness as a simple and reliable indicator of mechanical performance, one which could be easily implemented in improving tissue selection. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Transcatheter tissue engineered heart valves.

    Science.gov (United States)

    Emmert, Maximilian Y; Weber, Benedikt; Falk, Volkmar; Hoerstrup, Simon P

    2014-01-01

    Valvular heart disease represents a leading cause of mortality worldwide. Transcatheter heart valve replacement techniques have been recently introduced into the clinical routine expanding the treatment options for affected patients. However, despite this technical progress toward minimally invasive, transcatheter strategies, the available heart valve prostheses for these techniques are bioprosthetic and associated with progressive degeneration. To overcome such limitations, the concept of heart valve tissue engineering has been repeatedly suggested for future therapy concepts. Ideally, a clinically relevant heart valve tissue engineering concept would combine minimally invasive strategies for both, living autologous valve generation as well as valve implantation. Therefore, merging transcatheter techniques with living tissue engineered heart valves into a trascatheter tissue engineered heart valve concept could significantly improve current treatment options for patients suffering from valvular heart disease. This report provides an overview on transcatheter tissue engineered heart valves and summarizes available pre-clinical data.

  12. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves

    DEFF Research Database (Denmark)

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

    2014-01-01

    IMPORTANCE: Owing to a considerable shift toward bioprosthesis implantation rather than mechanical valves, it is expected that patients will increasingly present with degenerated bioprostheses in the next few years. Transcatheter aortic valve-in-valve implantation is a less invasive approach......, stroke, and New York Heart Association functional class. RESULTS: Modes of bioprosthesis failure were stenosis (n = 181 [39.4%]), regurgitation (n = 139 [30.3%]), and combined (n = 139 [30.3%]). The stenosis group had a higher percentage of small valves (37% vs 20.9% and 26.6% in the regurgitation...... and combined groups, respectively; P = .005). Within 1 month following valve-in-valve implantation, 35 (7.6%) patients died, 8 (1.7%) had major stroke, and 313 (92.6%) of surviving patients had good functional status (New York Heart Association class I/II). The overall 1-year Kaplan-Meier survival rate was 83...

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

    Science.gov (United States)

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

    2016-06-01

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

  14. Bioprosthetic Aortic Valve Endocarditis in Association with Enterococcus durans.

    Science.gov (United States)

    Fallavollita, Luca; Di Gioacchino, Lorena; Balestrini, Fabrizio

    2016-04-01

    Enterococci are common organisms associated with endocarditis, but infection by Enterococcus durans is very rare. To our knowledge, only 3 cases have been reported in the medical literature, and all 3 have involved native valves. Here we publish the first reported case (to our knowledge) of E. durans endocarditis in association with a bioprosthetic aortic valve. After the organism and its antibiotic susceptibility were identified, the 74-year-old male patient was treated successfully with teicoplanin and gentamicin, over a course of 6 weeks.

  15. Transcatheter Tricuspid Valve-in-Valve Implantation for the Treatment of Dysfunctional Surgical Bioprosthetic Valves: An International, Multicenter Registry Study.

    Science.gov (United States)

    McElhinney, Doff B; Cabalka, Allison K; Aboulhosn, Jamil A; Eicken, Andreas; Boudjemline, Younes; Schubert, Stephan; Himbert, Dominique; Asnes, Jeremy D; Salizzoni, Stefano; Bocks, Martin L; Cheatham, John P; Momenah, Tarek S; Kim, Dennis W; Schranz, Dietmar; Meadows, Jeffery; Thomson, John D R; Goldstein, Bryan H; Crittendon, Ivory; Fagan, Thomas E; Webb, John G; Horlick, Eric; Delaney, Jeffrey W; Jones, Thomas K; Shahanavaz, Shabana; Moretti, Carolina; Hainstock, Michael R; Kenny, Damien P; Berger, Felix; Rihal, Charanjit S; Dvir, Danny

    2016-04-19

    Off-label use of transcatheter aortic and pulmonary valve prostheses for tricuspid valve-in-valve implantation (TVIV) within dysfunctional surgical tricuspid valve (TV) bioprostheses has been described in small reports. An international, multicenter registry was developed to collect data on TVIV cases. Patient-related factors, procedural details and outcomes, and follow-up data were analyzed. Valve-in-ring or heterotopic TV implantation procedures were not included. Data were collected on 156 patients with bioprosthetic TV dysfunction who underwent catheterization with planned TVIV. The median age was 40 years, and 71% of patients were in New York Heart Association class III or IV. Among 152 patients in whom TVIV was attempted with a Melody (n=94) or Sapien (n=58) valve, implantation was successful in 150, with few serious complications. After TVIV, both the TV inflow gradient and tricuspid regurgitation grade improved significantly. During follow-up (median, 13.3 months), 22 patients died, 5 within 30 days; all 22 patients were in New York Heart Association class III or IV, and 9 were hospitalized before TVIV. There were 10 TV reinterventions, and 3 other patients had significant recurrent TV dysfunction. At follow-up, 77% of patients were in New York Heart Association class I or II (Pvalve size or TVIV valve type. TVIV with commercially available transcatheter prostheses is technically and clinically successful in patients of various ages across a wide range of valve size. Although preimplantation clinical status was associated with outcome, many patients in New York Heart Association class III or IV at baseline improved. TVIV should be considered a viable option for treatment of failing TV bioprostheses. © 2016 American Heart Association, Inc.

  16. Transcatheter Replacement of Failed Bioprosthetic Valves

    DEFF Research Database (Denmark)

    Simonato, Matheus; Webb, John; Kornowski, Ran

    2016-01-01

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

  17. Subclinical leaflet thrombosis in surgical and transcatheter bioprosthetic aortic valves

    DEFF Research Database (Denmark)

    Chakravarty, Tarun; Søndergaard, Lars; Friedman, John

    2017-01-01

    rates of transient ischaemic attacks (TIAs; 4·18 TIAs per 100 person-years vs 0·60 TIAs per 100 person-years; p=0·0005) and all strokes or TIAs (7·85 vs 2·36 per 100 person-years; p=0·001). INTERPRETATION: Subclinical leaflet thrombosis occurred frequently in bioprosthetic aortic valves, more commonly...... and transcatheter aortic valves and the effect of novel oral anticoagulants (NOACs) on the subclinical leaflet thrombosis and subsequent valve haemodynamics and clinical outcomes on the basis of two registries of patients who had CT imaging done after TAVR or SAVR. METHODS: Patients enrolled between Dec 22, 2014......, and Jan 18, 2017, in the RESOLVE registry, and between June 2, 2014, and Sept 28, 2016, in the SAVORY registry, had CT imaging done with a dedicated four-dimensional volume-rendered imaging protocol at varying intervals after TAVR and SAVR. We defined subclinical leaflet thrombosis as the presence...

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

    Science.gov (United States)

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

    2014-10-01

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

  19. Problem: Heart Valve Stenosis

    Science.gov (United States)

    ... Understanding Problems and Causes Heart Murmurs and Valve Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - Problem: Pulmonary Valve Stenosis Problem: Mitral ...

  20. Transcatheter Aortic Valve Replacement for Degenerative Bioprosthetic Surgical Valves

    DEFF Research Database (Denmark)

    Dvir, Danny; Webb, John; Brecker, Stephen

    2012-01-01

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

  1. 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.

  2. Emergency Valve-in-Valve Transcatheter Aortic Valve Implantation for the Treatment of Acute Stentless Bioprosthetic Aortic Insufficiency and Cardiogenic Shock

    Directory of Open Access Journals (Sweden)

    Ivan D. Hanson

    2018-01-01

    Full Text Available Bioprosthetic aortic valve degeneration may present as acute, severe aortic regurgitation and cardiogenic shock. Such patients may be unsuitable for emergency valve replacement surgery due to excessive risk of operative mortality but could be treatable with transfemoral valve-in-valve transcatheter aortic valve implantation (TAVI. There is a paucity of data regarding the feasibility of valve-in-valve TAVI in patients presenting with cardiogenic shock due to acute aortic insufficiency from stentless bioprosthetic valve degeneration. We present one such case, highlighting the unique aspects of valve-in-valve TAVI for this challenging patient subset.

  3. Evaluation of shrinkage temperature of bovine pericardium tissue for bioprosthetic heart valve application by differential scanning calorimetry and freeze-drying microscopy

    Directory of Open Access Journals (Sweden)

    Virgilio Tattini Jr

    2007-03-01

    Full Text Available Bovine pericardium bioprosthesis has become a commonly accepted device for heart valve replacement. Present practice relies on the measurement of shrinkage temperature, observed as a dramatic shortening of tissue length. Several reports in the last decade have utilized differential scanning calorimetry (DSC as an alternative method to determine the shrinkage temperature, which is accompanied by the absorption of heat, giving rise to an endothermic peak over the shrinkage temperature range of biological tissues. Usually, freeze-drying microscope is used to determine collapse temperature during the lyophilization of solutions. On this experiment we used this technique to study the shrinkage event. The aim of this work was to compare the results of shrinkage temperature obtained by DSC with the results obtained by freeze-drying microscopy. The results showed that both techniques provided excellent sensitivity and reproducibility, and gave information on the thermal shrinkage transition via the thermodynamical parameters inherent of each method.

  4. National trends in utilization and in-hospital outcomes of mechanical versus bioprosthetic aortic valve replacements.

    Science.gov (United States)

    Isaacs, Abby J; Shuhaiber, Jeffrey; Salemi, Arash; Isom, O Wayne; Sedrakyan, Art

    2015-05-01

    Substantial controversy surrounds the choice between a mechanical versus bioprosthetic prosthesis for aortic valve replacement (AVR), based on age. This study aims to investigate national trends and in-hospital outcomes of the 2 prosthesis choices. All patients aged >18 years in the National Inpatient Sample who received an AVR between 1998 and 2011 were considered. Valve-type use was examined by patient, procedural, and hospital characteristics, after which we matched patients based on their propensity score for receiving a bioprosthetic valve and compared their in-hospital outcomes. Bioprosthetic valves comprised 53.3% of 767,375 implanted valves, an increase in use from 37.7% in the period 1998 to 2001 to 63.6% in the period 2007 to 2011. The median age was 74 years for patients receiving bioprosthetic valves, and 67 years for those receiving mechanical valves. Use of bioprosthetic valves increased across all age groups, most markedly in patients age 55 to 64 years. Compared with patients receiving mechanical valves, these patients had a higher incidence of renal disease (8.0% vs 4.2%), coronary artery disease (58.5% vs 50.5%), concomitant coronary artery bypass grafting (46.7% vs 41.9%), and having surgery in a high-volume (>250 cases per year) center (31.3% vs 18.5%). Patients receiving bioprosthetic valves had a higher occurrence of in-hospital complications (55.9% vs 48.6%), but lower in-hospital mortality (4.4% vs 4.9%) than patients receiving mechanical valves. This difference was confirmed in propensity-matched analyses (complications: 52.7% vs 51.5%; mortality: 4.3% vs 5.2%). Use of bioprosthetic valves in AVR increased dramatically from 1998 to 2011, particularly in patients age 55 to 64 years. Prosthesis selection varied significantly by facility, with low-volume facilities favoring mechanical valves. Aortic valve replacement with a bioprosthetic valve, compared with a mechanical valve, was associated with lower in-hospital mortality. Copyright © 2015

  5. Design of Bioprosthetic Aortic Valves using biaxial test data.

    Science.gov (United States)

    Dabiri, Y; Paulson, K; Tyberg, J; Ronsky, J; Ali, I; Di Martino, E; Narine, K

    2015-01-01

    Bioprosthetic Aortic Valves (BAVs) do not have the serious limitations of mechanical aortic valves in terms of thrombosis. However, the lifetime of BAVs is too short, often requiring repeated surgeries. The lifetime of BAVs might be improved by using computer simulations of the structural behavior of the leaflets. The goal of this study was to develop a numerical model applicable to the optimization of durability of BAVs. The constitutive equations were derived using biaxial tensile tests. Using a Fung model, stress and strain data were computed from biaxial test data. SolidWorks was used to develop the geometry of the leaflets, and ABAQUS finite element software package was used for finite element calculations. Results showed the model is consistent with experimental observations. Reaction forces computed by the model corresponded with experimental measurements when the biaxial test was simulated. As well, the location of maximum stresses corresponded to the locations of frequent tearing of BAV leaflets. Results suggest that BAV design can be optimized with respect to durability.

  6. Assessment of structural valve deterioration of transcatheter aortic bioprosthetic balloon-expandable valves using the new European consensus definition.

    Science.gov (United States)

    Eltchaninoff, Hélène; Durand, Eric; Avinée, Guillaume; Tron, Christophe; Litzler, Pierre-Yves; Bauer, Fabrice; Dacher, Jean-Nicolas; Werhlin, Camille; Bouhzam, Najime; Bettinger, Nicolas; Candolfi, Pascal; Cribier, Alain

    2018-03-30

    Durability of transcatheter aortic bioprosthetic valves remains a major issue. Standardised definitions of deterioration and failure of bioprosthetic valves have recently been proposed. The aim of this study was to assess structural transcatheter valve deterioration (SVD) and bioprosthetic valve failure (BVF) using these new definitions. All TAVI patients implanted up to September 2012 with a minimal theoretical five-year follow-up were included. Systematic clinical and echocardiographic follow-up was performed annually. New standardised definitions were used to assess durability of transcatheter aortic bioprosthetic valves. From 2002 to 2012, 378 patients were included. Mean age and logistic EuroSCORE were 83.3±6.8 years and 22.8±13.1%. Thirty-day mortality was 13.2%. Nine patients had SVD including two severe forms and two patients had definite late BVF. The incidence of SVD and BVF at eight years was 3.2% (95% CI: 1.45-6.11) and 0.58% (95% CI: 0.15-2.75), respectively. Even though limited by the poor survival of the very high-risk/compassionate early population, our data do not demonstrate any alarm concerning transcatheter aortic valve durability. Careful prospective assessment in younger and lower-risk patients and comparison with surgical bioprosthetic valves are required for further assessment of the long-term durability of transcatheter valves.

  7. 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

  8. In vitro 2D PIV measurements and related aperture areas of tricuspid bioprosthetic mitral valves at the beginning of diastole.

    Science.gov (United States)

    Bazan, Ovandir; Ortiz, Jayme Pinto; Fukumasu, Newton Kiyoshi; Pacifico, Antonio Luiz; Yanagihara, Jurandir Itizo

    2016-07-04

    Besides ventricular parameters, the design and angular orientation of a prosthetic heart valve induce a specific flow field. The aim of this study was to know the inflow characteristics of a left ventricular model (LVM), investigating the behavior of tricuspid bioprosthetic mitral valves in terms of velocity profiles and related valve aperture areas at the beginning of diastole, under different conditions. 3 heart rates (HRs) were established in the LVM and each mitral bioprosthesis (27 and 31 mm diameter) was installed in 2 orientations, rotated by 180° . For each experimental setup, 2-dimensional particle image velocimetry (2D PIV) measurements and simultaneous mitral valve (MV) area detection were obtained from 50 samples. The results from the velocity profiles immediately downstream of mitral bioprostheses showed the influence of valve orientation for moderate HRs, although for a similar magnitude of mean velocity vectors. The geometries of MV open areas for each HR were similar regardless of valve orientation, except for the 27-mm valve at 90 beats per minute (bpm), and for the 31-mm valve at 60 bpm. Moreover, for each HR, similar percentages of valve open area were obtained regardless of MV nominal diameters. In conclusion, the experimental setup for the 2D PIV measurements synchronized with the MV area detection was a useful tool for knowing the inflow characteristics of the LVM.

  9. Percutaneous bioprosthetic venous valve: a long-term study in sheep.

    Science.gov (United States)

    Pavcnik, Dusan; Uchida, Barry T; Timmermans, Hans A; Corless, Christopher L; O'Hara, Michael; Toyota, Naoyuki; Moneta, Gregory L; Keller, Frederick S; Rösch, Josef

    2002-03-01

    A long-term evaluation of a new percutaneously placed bioprosthetic, bicuspid venous valve (BVV) consisting of a square stent and small intestinal submucosa (SIS) covering was performed in 12 sheep. Of 26 BVVs placed into the jugular veins, 25 exhibited good valve function on immediate venography and 22 on venograms obtained before the sheep were killed. Gross and histologic examination results demonstrated incorporation of remodeled and endothelialized SIS BVVs into the vein wall. Slight to moderate leaflet thickening was found mostly at their bases. Percutaneously placed SIS BVV is a promising one-way, competent valve that resists venous back-pressure while allowing forward flow.

  10. 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 ...

  11. 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 ...

  12. Mechanical versus bioprosthetic mitral valve replacement in patients <65 years old.

    Science.gov (United States)

    Kaneko, Tsuyoshi; Aranki, Sary; Javed, Quratulain; McGurk, Siobhan; Shekar, Prem; Davidson, Michael; Cohn, Lawrence

    2014-01-01

    Because of its durability, the mechanical valve is typically chosen for young patients undergoing mitral valve replacement (MVR). However, a bioprosthetic valve might have the benefit of valve-in-valve transcatheter valve replacement when valve failure occurs. We examined the outcomes in patients who had undergone mechanical valve MVR (MVRm) versus bioprosthetic valve MVR (MVRb) in patients aged Security Death Index. The postoperative and long-term outcomes of interest included combined stroke and embolic events, reoperations, and mortality. Of 768 consecutive patients, 627 were in the MVRm and 141 in the MVRb group. Propensity score matching yielded a cohort of 125 MVRb (89%) and 125 control MVRm patients with similar etiology mixes. The groups were similar in age (MVRm, 53.2 ± 9.0 years; MVRb, 53.8 ± 10.6 years; P = .617) and other preoperative characteristics. The postoperative outcomes were also similar between the 2 groups, including reoperation for bleeding, stroke, deep sternal infection, sepsis, and length of hospital stay. The operative mortality was also similar (MVRm, 5.6%; MVRb, 8.0%; P = .617). However, Kaplan-Meier analysis showed the MVRb group had a greater reoperation rate (P = .001) and shorter estimated survival (11.3 vs 13.5 years, P = .004). The incidence of bleeding and stroke or embolic events between the 2 groups was similar. In the present report, MVRb for patients safety of mechanical valves in this group. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  13. Possible Subclinical Leaflet Thrombosis in Bioprosthetic Aortic Valves

    DEFF Research Database (Denmark)

    Makkar, Raj R; Fontana, Gregory; Jilaihawi, Hasan

    2015-01-01

    BACKGROUND: A finding of reduced aortic-valve leaflet motion was noted on computed tomography (CT) in a patient who had a stroke after transcatheter aortic-valve replacement (TAVR) during an ongoing clinical trial. This finding raised a concern about possible subclinical leaflet thrombosis and pr...

  14. 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.

  15. What Is Heart Valve Disease?

    Science.gov (United States)

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

  16. Biological heart valves.

    Science.gov (United States)

    Ciubotaru, Anatol; Cebotari, Serghei; Tudorache, Igor; Beckmann, Erik; Hilfiker, Andres; Haverich, Axel

    2013-10-01

    Cardiac valvular pathologies are often caused by rheumatic fever in young adults, atherosclerosis in elderly patients, or by congenital malformation of the heart in children, in effect affecting almost all population ages. Almost 300,000 heart valve operations are performed worldwide annually. Tissue valve prostheses have certain advantages over mechanical valves such as biocompatibility, more physiological hemodynamics, and no need for life-long systemic anticoagulation. However, the major disadvantage of biological valves is related to their durability. Nevertheless, during the last decade, the number of patients undergoing biological, rather than mechanical, valve replacement has increased from half to more than three-quarters for biological implants. Continuous improvement in valve fabrication includes development of new models and shapes, novel methods of tissue treatment, and preservation and implantation techniques. These efforts are focused not only on the improvement of morbidity and mortality of the patients but also on the improvement of their quality of life. Heart valve tissue engineering aims to provide durable, "autologous" valve prostheses. These valves demonstrate adaptive growth, which may avoid the need of repeated operations in growing patients.

  17. Optimal thromboprophylaxis following bioprosthetic aortic valve replacement: still a matter of debate?

    Science.gov (United States)

    Mydin, Muhammad I; Dimitrakakis, Georgios; Younis, Jenan; Nowell, Justin; Athanasiou, Thanos; Kourliouros, Antonios

    2012-07-01

    Optimal thromboprophylaxis following bioprosthetic aortic valve replacement (AVR) remains controversial. The main objective, which is the effective prevention of central nervous or peripheral embolic events, especially in the early postoperative period, will have to be weighed against the haemorrhagic risk that is associated with the utilization of different antithrombotic regimes. Most governing bodies in cardiovascular medicine have issued recommendations on thromboprophylaxis after the surgical implantation of aortic bioprostheses. However, the level of evidence to support these recommendations remains low, largely due to the inherent limitations of conducting appropriately randomized and adequately powered clinical research in this area. It is apparent from the recent surveys and large registries that there is a great variability in antithrombotic practice at an institutional or individual-clinician level reflecting this controversy and the lack of robust evidence. While organizational, financial or conceptual limitations could hinder the conduct and availability of conclusive research on optimal thromboprophylaxis after aortic bioprosthesis, it is imperative that all evidence is presented in a systematic way in order to assist the decision-making for the modern clinician. In this review, we provide an outline of the current recommendations for thromboprophylaxis, followed by a comprehensive and analytical presentation of all comparative studies examining anticoagulation vs. antiplatelet therapy after bioprosthetic AVR.

  18. Prosthetic heart valves.

    Science.gov (United States)

    Chambers, J

    2014-10-01

    Heart valve replacements improve symptoms and life expectancy but may have potential problems. Biological replacements have limited durability but do not require anticoagulation and are usually used for the relatively elderly. Mechanical valves have a virtually zero primary failure rate but require anticoagulation and are usually used for the relatively younger patient. Transcatheter valves are used for patients in whom conventional surgery is not technically feasible or who have significant comorbidities. This article discusses the management of patients after valve replacement and discusses future developments. © 2014 John Wiley & Sons Ltd.

  19. When a Heart Murmur Signals Valve Disease

    Science.gov (United States)

    ... Understanding Problems and Causes Heart Murmurs and Valve Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - Problem: Pulmonary Valve Stenosis Problem: Mitral ...

  20. Paravalvular mitral valve leakage presenting as congestive heart failure, missed by TTE but diagnosed by TEE: a case report.

    Science.gov (United States)

    Jayawardena, Suriya; Sooriabalan, Danushan; Burzyantseva, Olga; Sinnapunayagm, Selvaratnam

    2008-10-06

    Diagnosis of prosthetic valve leakage by the transthoracic echocardiogram (TTE) technique is more difficult. These limitations are diminished with the use of transesophageal echocardiogram (TEE) techniques. A 71 year old Caucasian male presented with symptoms and signs of congestive heart failure. Past medical history included a bio-prosthetic mitral valve replacement for severe mitral regurgitation. TTE showed possible mitral regurgitation. As the TTE did not correlate with the finding of a high E-velocity, a TEE was performed, which showed a significant paravalvular leak of moderate severity around the bio-prosthetic mitral valve. There should be a high degree of suspicion to diagnose a paravalvular leak.

  1. Outcome of bioprosthetic valve replacement in dogs with tricuspid valve dysplasia.

    Science.gov (United States)

    Bristow, P; Sargent, J; Luis Fuentes, V; Brockman, D

    2017-04-01

    To describe the short-term and long-term outcome in dogs with tricuspid valve dysplasia undergoing tricuspid valve replacement under cardiopulmonary bypass. Data were collected from the hospital records of all dogs that had undergone tricuspid valve replacement under cardiopulmonary bypass between 2006 and 2012. Dogs were considered candidates for tricuspid valve replacement if they had severe tricuspid valve regurgitation associated with clinical signs of cardiac compromise. Nine dogs of six different breeds were presented. Median age was 13 months (range 7 to 61 months), median weight 26·5 kg (range 9·7 to 59 kg). Eight bovine pericardial valves and one porcine aortic valve were used. One non-fatal intraoperative complication occurred. Complications during hospitalisation occurred in six dogs, four of which were fatal. Of the five dogs discharged, one presented dead due to haemothorax after minor trauma seven days later. The four remaining dogs survived a median of 533 days; all of these dogs received a bovine pericardial valve. Based on our results, tricuspid valve replacement with bovine or porcine prosthetic valves is associated with a high incidence of complications. © 2017 British Small Animal Veterinary Association.

  2. 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...

  3. 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.

  4. Telocytes in human heart valves.

    Science.gov (United States)

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

    2014-05-01

    Valve interstitial cells (VICs) are responsible for maintaining the structural integrity and dynamic behaviour of the valve. Telocytes (TCs), a peculiar type of interstitial cells, have been recently identified by Popescu's group in epicardium, myocardium and endocardium (visit www.telocytes.com). The presence of TCs has been identified in atria, ventricles and many other tissues and organ, but not yet in heart valves. We used transmission electron microscopy and immunofluorescence methods (double labelling for CD34 and c-kit, or vimentin, or PDGF Receptor-β) to provide evidence for the existence of TCs in human heart valves, including mitral valve, tricuspid valve and aortic valve. TCs are found in both apex and base of heart valves, with a similar density of 27-28 cells/mm(2) in mitral valve, tricuspid valve and aortic valve. Since TCs are known for the participation in regeneration or repair biological processes, it remains to be determined how TCs contributes to the valve attempts to re-establish normal structure and function following injury, especially a complex junction was found between TCs and a putative stem (progenitor) cell. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  5. 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

  6. Non-linear rotation-free shell finite-element models for aortic heart valves.

    Science.gov (United States)

    Gilmanov, Anvar; Stolarski, Henryk; Sotiropoulos, Fotis

    2017-01-04

    Hyperelastic material models have been incorporated in the rotation-free, large deformation, shell finite element (FE) formulation of (Stolarski et al., 2013) and applied to dynamic simulations of aortic heart valve. Two models used in the past in analysis of such problem i.e. the Saint-Venant and May-Newmann-Yin (MNY) material models have been considered and compared. Uniaxial tests for those constitutive equations were performed to verify the formulation and implementation of the models. The issue of leaflets interactions during the closing of the heart valve at the end of systole is considered. The critical role of using non-linear anisotropic model for proper dynamic response of the heart valve especially during the closing phase is demonstrated quantitatively. This work contributes an efficient FE framework for simulating biological tissues and paves the way for high-fidelity flow structure interaction simulations of native and bioprosthetic aortic heart valves. Copyright © 2016. Published by Elsevier Ltd.

  7. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    Most commonly used for replacement are mechanical heart valves and biological valves. This paper briefly outlines the evolution, designs employed, materials being used,. and important factors that affect the performance of mechanical heart valves. The clinical performance of mechanical heart valves is also addressed.

  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. 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.

  10. 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.

  11. Tissue-engineered heart valves

    Czech Academy of Sciences Publication Activity Database

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

    2009-01-01

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

  12. Developments in mechanical heart valve prosthesis

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    Mechanical heart valves; biological valves; valve design; valve performance. 1. Introduction. The human heart can be considered a twin positive displacement pump working in tandem for supporting the systemic and pulmonary circulation of blood. Each pump comprises of a receiving chamber called atrium and a pumping ...

  13. Outcomes in nonagenarians after heart valve replacement operation.

    Science.gov (United States)

    Edwards, Maria-Benedicta; Taylor, Kenneth M

    2003-03-01

    Changes in the age profile of the United Kingdom population and improvements in preoperative and postoperative care have resulted in increasing numbers of very elderly patients undergoing heart valve replacement (HVR) operations. Although HVR operations in nonagenarians are relatively uncommon, the demand for cardiac operations in this age group may increase over time. Outcomes after HVR operations in nonagenarians have not been well described yet. Therefore, the aim of this study was to determine outcomes in terms of early mortality and long-term survival in 35 nonagenarians after HVR operation. Data from the United Kingdom Heart Valve Registry were analyzed and nonagenarian patients were identified. Additional analyzed data include gender, valve position, valve type, valve size, operative priority, follow-up time, and date and cause of death. Kaplan-Meier actuarial curves were calculated to determine accurate 30-day mortality and long-term survival. On average five HVR operations are performed annually in the United Kingdom in nonagenarians with equal numbers of males and females. Aortic valve replacement with a bioprosthetic valve was the most common operation and 86% were elective admissions. Fourteen patients died within the review period; mean time to death was 402 days. Overall 30-day mortality was 17%, which was higher for males compared with females; females also displayed better long-term survival. HVR operations in nonagenarians carry a significantly higher risk of early mortality and reduced long-term survival. Despite increases in the age profile of the population, elective HVR operation with patients aged 90 years or older is likely to remain an infrequent surgical procedure reserved for very carefully selected patients.

  14. 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

  15. Clinical performance of mechanical versus bioprosthetic valves in patients aged 60-70 years

    Directory of Open Access Journals (Sweden)

    Si-ming ZHU

    2017-06-01

    Full Text Available Objective To compare the mortality, valve-related morbidity and reoperation rate between mechanical prostheses and bioprostheses in patients aged 60 to 70 years. Methods The pre-operative characteristics of 119 patients who received mechanical prostheses and 181 those with bioprosthesis implantation in our department between January 2006 and December 2014 were analyzed, and their mortality, valve-related morbidity and reoperation rate were compared. Results Follow-up revealed mechanical prostheses had a lower all-cause mortality after mitral valve replacement than bioprostheses at 6 years after the operation (P=0.033, but there was no statistical difference in valve-related mortality (P=0.277. The complications after mechanical prosthesis replacement had embolism (8.4% and bleeding (5.0%, bioprosthesis' those consisted of structural valvular deterioration (2.2%, nonstructural dysfunction (1.1%, thrombosis (2.8%, embolism (5.0%, bleeding (0.6% and operated valvular endocarditis (1.1%. There was no statistically significant difference in total complication rate between the two groups (P=0.318. Biological group had 3 patients receiving reoperation in 8 years, while there was no reoperation in the mechanical group, but without statistical group difference. Conclusion Patients aged 60-70 years old could have a similar valve-related mortality, morbidity and reoperation rate after mitral valve replacement between mechanical and biological valves. DOI: 10.11855/j.issn.0577-7402.2017.05.19

  16. A Tri-Leaflet Nitinol Mesh Scaffold for Engineering Heart Valves.

    Science.gov (United States)

    Alavi, S Hamed; Soriano Baliarda, Marc; Bonessio, Noemi; Valdevit, Lorenzo; Kheradvar, Arash

    2017-02-01

    The epidemiology of valvular heart disease has significantly changed in the past few decades with aging as one of the main contributing factors. The available options for replacement of diseased valves are currently limited to mechanical and bioprosthetic valves, while the tissue engineered ones that are under study are currently far from clinical approval. The main problem with the tissue engineered heart valves is their progressive deterioration that leads to regurgitation and/or leaflet thickening a few months after implantation. The use of bioresorbable scaffolds is speculated to be one factor affecting these valves' failure. We have previously developed a non-degradable superelastic nitinol mesh scaffold concept that can be used for heart valve tissue engineering applications. It is hypothesized that the use of a non-degradable superelastic nitinol mesh may increase the durability of tissue engineered heart valves, avoid their shrinkage, and accordingly prevent regurgitation. The current work aims to study the effects of the design features on mechanical characteristics of this valve scaffold to attain proper function prior to in vivo implantation.

  17. 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.

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    Aims: Four-dimensional volume-rendered computed tomography (4DCT) has demonstrated instances of hypo-attenuating leaflet thickening (HALT) with or without hypo-attenuation affecting motion (HAM) after transcatheter and surgical aortic valve implantation (TAVI, SAVR). The temporal pattern of evolu...

  19. 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.

  20. Minimally-invasive implantation of living tissue engineered heart valves: a comprehensive approach from autologous vascular cells to stem cells.

    Science.gov (United States)

    Schmidt, Dörthe; Dijkman, Petra E; Driessen-Mol, Anita; Stenger, Rene; Mariani, Christine; Puolakka, Arja; Rissanen, Marja; Deichmann, Thorsten; Odermatt, Bernhard; Weber, Benedikt; Emmert, Maximilian Y; Zund, Gregor; Baaijens, Frank P T; Hoerstrup, Simon P

    2010-08-03

    The aim of this study was to demonstrate the feasibility of combining the novel heart valve replacement technologies of: 1) tissue engineering; and 2) minimally-invasive implantation based on autologous cells and composite self-expandable biodegradable biomaterials. Minimally-invasive valve replacement procedures are rapidly evolving as alternative treatment option for patients with valvular heart disease. However, currently used valve substitutes are bioprosthetic and as such have limited durability. To overcome this limitation, tissue engineering technologies provide living autologous valve replacements with regeneration and growth potential. Trileaflet heart valves fabricated from biodegradable synthetic scaffolds, integrated in self-expanding stents and seeded with autologous vascular or stem cells (bone marrow and peripheral blood), were generated in vitro using dynamic bioreactors. Subsequently, the tissue engineered heart valves (TEHV) were minimally-invasively implanted as pulmonary valve replacements in sheep. In vivo functionality was assessed by echocardiography and angiography up to 8 weeks. The tissue composition of explanted TEHV and corresponding control valves was analyzed. The transapical implantations were successful in all animals. The TEHV demonstrated in vivo functionality with mobile but thickened leaflets. Histology revealed layered neotissues with endothelialized surfaces. Quantitative extracellular matrix analysis at 8 weeks showed higher values for deoxyribonucleic acid, collagen, and glycosaminoglycans compared to native valves. Mechanical profiles demonstrated sufficient tissue strength, but less pliability independent of the cell source. This study demonstrates the principal feasibility of merging tissue engineering and minimally-invasive valve replacement technologies. Using adult stem cells is successful, enabling minimally-invasive cell harvest. Thus, this new technology may enable a valid alternative to current bioprosthetic devices

  1. 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

  2. What Is Heart Valve Surgery?

    Science.gov (United States)

    ... working correctly. Most valve replacements involve the aortic Tricuspid valve and mitral valves. The aortic valve separates the ... in life and cause problems. •Aging can make valves weaken or harden. • Certain diseases can scar or destroy a valve. What can ...

  3. 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

  4. 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

  5. Tissue-engineered heart valves.

    Science.gov (United States)

    Filová, E; Straka, F; Mirejovský, T; Masín, J; Bacáková, L

    2009-01-01

    Currently-used mechanical and biological heart valve prostheses have several disadvantages. Mechanical prostheses, based on carbon, metallic and polymeric components, require permanent anticoagulation treatment, and their usage often leads to adverse reactions, e.g. thromboembolic complications and endocarditis. Xenogenous and allogenous biological prostheses are associated with immune reaction, thrombosis and degeneration, and thus they have a high rate of reoperation. Biological prostheses of autologous origin, such as pulmonary autografts, often burden the patient with a complicated surgery and the risk of reoperation. Therefore, efforts are being made to prepare bioartificial heart valves with an autologous biological component by methods of tissue engineering. They should be biocompatible, durable, endowed with appropriate mechanical properties and able to grow with a child. For this purpose, scaffolds composed of synthetic materials, such as poly(lactic acid), poly(caprolactone), poly(4-hydroxybutyrate), hydrogels or natural polymers, e.g. collagen, elastin, fibrin or hyaluronic acid, have been seeded with autologous differentiated, progenitor or stem cells. Promising results have been obtained with nanostructured scaffolds, and also with cultivation in special dynamic bioreactors prior to implantation of the bioartificial grafts into an animal organism.

  6. Heart valve disease among patients with hyperprolactinemia

    DEFF Research Database (Denmark)

    Steffensen, Maria 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....

  7. 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 De...

  8. Options for Heart Valve Replacement

    Science.gov (United States)

    ... are the most commonly replaced valves. Pulmonary and tricuspid valve replacements are fairly uncommon in adults. Replacing a ... Problems and Causes • Risks, Signs and Symptoms • Accurate Diagnosis • Treatment Options ... Repair Valve Replacement - Ross Procedure - Newer Surgery Options - ...

  9. Clinical Outcomes of the David V Valve-Sparing Root Replacement Compared With Bioprosthetic Valve-Conduits for Aortic Root Aneurysms.

    Science.gov (United States)

    Esaki, Jiro; Leshnower, Bradley G; Binongo, Jose N; Lasanajak, Yi; McPherson, LaRonica; Halkos, Michael E; Guyton, Robert A; Chen, Edward P

    2017-06-01

    Valve-sparing root replacement (VSRR) is an established therapy for aortic root pathology. Limited insight exists when the results of VSRR are compared with those of conventional root replacement with use of a bioprosthetic composite conduit (BIO). This study compares the operative and midterm results of VSRR and BIO. A retrospective review from 2002 to 2015 at a United States academic center identified 282 patients who underwent VSRR and 425 patients who underwent BIO. Propensity-score matching was performed based on 20 preoperative characteristics, and 123 matched pairs were identified. The mean age (VSRR 53.5 ± 11.1, BIO 53.0 ± 13.0; p = 0.74) and left ventricular ejection fraction (VSRR 54.5 ± 9.2%, BIO 54.4 ± 9.4%; p = 0.99) were equivalent in both groups. The incidence of bicuspid valves (VSRR 26.0%, BIO 27.6%; p = 0.77), Marfan syndrome (VSRR 6.5%, BIO 4.9%; p = 0.58), type A dissection (VSRR 13.0%, BIO 13.0%; p = 0.99), reoperation (VSRR 15.4%, BIO 20.3%; p = 0.32) and arch replacement (VSRR 60.2%, BIO 63.4%; p = 0.60) were similar between the groups. Operative mortality was 5.7% in VSRR and 0.8% in BIO (p = 0.07). There were no significant differences in postoperative renal failure (VSRR 0.8%, BIO 0.0%; p = 0.99) or stroke (VSRR 3.3%, BIO 0.8%; p = 0.37) between the groups. The 7-year survival (VSSR 82.4%, BIO 83.0%; p = 0.53), 7-year freedom from reoperation (VSRR 97.4%, BIO 95.8%; p = 0.48), and 7-year freedom from greater than moderate aortic insufficiency (AI) (VSRR 98.1%, BIO 100.0%; p = 0.47) were similar between groups. VSRR and BIO result in equivalent operative mortality and morbidity with similar midterm survival and valve durability. VSRR is an effective alternative to BIO for aortic root pathologic conditions; however, careful patient selection is paramount. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  10. The radiology of prosthetic heart valves

    International Nuclear Information System (INIS)

    Steiner, R.M.; Flicker, S.

    1985-01-01

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

  11. Bioengineered self-seeding heart valves.

    Science.gov (United States)

    Jordan, James E; Williams, J Koudy; Lee, Sang-Jin; Raghavan, Devanathan; Atala, Anthony; Yoo, James J

    2012-01-01

    Mechanical and biological prostheses are used to replace damaged heart valves but are associated with significant morbidities. Although there is increased interest in bioengineering cell-seeded heart valve scaffolds, it is a time-consuming and technically difficult process. The goal of this project was to engineer self-seeding heart valves that mature quickly in vivo and have a shorter preparation time. Porcine pulmonary valves were decellularized using detergent methods and then either (1) left untreated (unconjugated, n = 6), (2) reseeded with autologous endothelial progenitor cell-derived endothelial cells (cell-seeded, n = 4), or (3) conjugated with CD133 antibodies (conjugated, n = 8). The valve constructs were transplanted into the pulmonary position of sheep using standard surgical techniques. After 1 or 3 months, the implants were removed and assessed for cell and matrix content as well as biomechanical properties. Endothelial cells expressing von Willebrand factor lined the entire length of both ventricular and arterial surfaces of conjugated valves by 1 month after implantation. Interstitial cell and structural protein content of conjugated valves increased from 1 month to 3 months with interstitial expression of metalloproteinase-9 and new collagen formation. In contrast, there were few endothelial or interstitial cells associated with unconjugated, or cell-seeded valves at any time point. No calcification or thrombi were noted on any of the valves. Young's modulus and tensile strength was greater in the conjugated valves versus unconjugated or cell-seeded valves. Results indicate that tissue-engineered heart valve replacement constructs can be made quickly and therefore may be a clinically relevant option for patients needing heart valve surgery in a timely fashion. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  12. Heart Valve Biomechanics and Underlying Mechanobiology

    Science.gov (United States)

    Ayoub, Salma; Ferrari, Giovanni; Gorman, Robert C.; Gorman, Joseph H.; Schoen, Frederick J.; Sacks, Michael S.

    2017-01-01

    Heart valves control unidirectional blood flow within the heart during the cardiac cycle. They have a remarkable ability to withstand the demanding mechanical environment of the heart, achieving lifetime durability by processes involving the ongoing remodeling of the extracellular matrix. The focus of this review is on heart valve functional physiology, with insights into the link between disease-induced alterations in valve geometry, tissue stress, and the subsequent cell mechanobiological responses and tissue remodeling. We begin with an overview of the fundamentals of heart valve physiology and the characteristics and functions of valve interstitial cells (VICs). We then provide an overview of current experimental and computational approaches that connect VIC mechanobiological response to organ- and tissue-level deformations and improve our understanding of the underlying functional physiology of heart valves. We conclude with a summary of future trends and offer an outlook for the future of heart valve mechanobiology, specifically, multiscale modeling approaches, and the potential directions and possible challenges of research development. PMID:27783858

  13. [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.

  14. 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.

  15. Tissue-engineered heart valve with a tubular leaflet design for minimally invasive transcatheter implantation.

    Science.gov (United States)

    Moreira, Ricardo; Velz, Thaddaeus; Alves, Nuno; Gesche, Valentine N; Malischewski, Axel; Schmitz-Rode, Thomas; Frese, Julia; Jockenhoevel, Stefan; Mela, Petra

    2015-06-01

    Transcatheter aortic valve implantation of (nonviable) bioprosthetic valves has been proven a valid alternative to conventional surgical implantation in patients at high or prohibitive mortality risk. In this study we present the in vitro proof-of-principle of a newly developed tissue-engineered heart valve for minimally invasive implantation, with the ultimate aim of adding the unique advantages of a living tissue with regeneration capabilities to the continuously developing transcatheter technologies. The tube-in-stent is a fibrin-based tissue-engineered valve with a tubular leaflet design. It consists of a tubular construct sewn into a self-expandable nitinol stent at three commissural attachment points and along a circumferential line so that it forms three coaptating leaflets by collapsing under diastolic back pressure. The tubular constructs were molded with fibrin and human umbilical vein cells. After 3 weeks of conditioning in a bioreactor, the valves were fully functional with unobstructed opening (systolic phase) and complete closure (diastolic phase). Tissue analysis showed a homogeneous cell distribution throughout the valve's thickness and deposition of collagen types I and III oriented along the longitudinal direction. Immunohistochemical staining against CD31 and scanning electron microscopy revealed a confluent endothelial cell layer on the surface of the valves. After harvesting, the valves underwent crimping for 20 min to simulate the catheter-based delivery. This procedure did not affect the valvular functionality in terms of orifice area during systole and complete closure during diastole. No influence on the extracellular matrix organization, as assessed by immunohistochemistry, nor on the mechanical properties was observed. These results show the potential of combining tissue engineering and minimally invasive implantation technology to obtain a living heart valve with a simple and robust tubular design for transcatheter delivery. The effect

  16. 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.

  17. Patents and heart valve surgery - II: tissue valves.

    Science.gov (United States)

    Cheema, Faisal H; Kossar, Alexander P; Rehman, Atiq; Younas, Fahad; Polvani, Gianluca

    2013-08-01

    Valvular heart disease affects millions of Americans yearly and currently requires surgical intervention to repair or replace the defective valves. Through a close-knit collaboration between physicians, scientists and biomedical engineers, a vast degree of research and development has been aimed towards the optimization of prosthetic heart valves. Although various methods have made fantastic strides in producing durable prostheses, the therapeutic efficacy of prosthetic valves is inherently limited by a dependency upon lifelong anticoagulant regimens for recipients - a difficult challenge for many in clinical setting. Thus, biological tissue valves have been developed to circumvent vascular and immunemediated complications by incorporating biological materials to mimic native valves while still maintaining a necessary level of structural integrity. Over the past decade, a multitude of patents pertaining to the refinement of designs as well as the advancement in methodologies and technologies associated with biological tissue valves have been issued. This review seeks to chronicle and characterize such patents in an effort to track the past, present, and future progress as well as project the trajectory of tissue valves in the years to come.

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

    Science.gov (United States)

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

    2011-08-23

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

  19. 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.

  20. Current Challenges in Translating Tissue-Engineered Heart Valves

    NARCIS (Netherlands)

    Stassen, O M J A; Muylaert, D E P; Bouten, Carlijn V. C.; Hjortnaes, J; Hjortnaes, J

    OPINION STATEMENT: Heart valve disease is a major health burden, treated by either valve repair or valve replacement, depending on the affected valve. Nearly 300,000 valve replacements are performed worldwide per year. Valve replacement is lifesaving, but not without complications. The in situ

  1. 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.

  2. 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.

  3. Application of wavelet analysis to the phonocardiographic signal of mechanical heart valve closing sounds.

    Science.gov (United States)

    Bagno, Andrea; Anzil, Federico; Tarzia, Vincenzo; Pengo, Vittorio; Ruggeri, Alfredo; Gerosa, Gino

    2009-03-01

    Heart valve disorders, caused by congenital defects, rheumatic fever, calcification, myocardial infarction and other cardiovascular diseases, often require native valves to be replaced by bio-prosthetic devices or mechanical heart valves (MHVs). Among MHVs, bileaflet valves are usually preferred for their hemodynamic features, similar to physiological ones, and their durability, but they are prone to complications due to thromboembolic events. Due to the asynchronous closure of the leaflets, bileaflet MHVs are also known to produce closing sounds typically characterized by the presence of two peaks in the time domain. The detection of this "double click" in the signal may be useful for the early diagnosis of bileaflet MHV malfunction. The closing sound is actually a non-stationary signal that can be properly explored by means of time-frequency analysis. This paper describes a preliminary approach to the investigation of bileaflet MHV closing sounds performed by Continuous Wavelet Transform (CWT) analysis. Signals were collected from 3 patients immediately after surgery by means of the Myotis 3C, which is a traditional phonocardiographic apparatus. Signals were analyzed by two algorithms: one embedded in the Myotis 3C, based on the Fast Fourier Transform (FFT); and one specifically created for the purposes of the present study, based on CWT. The performance of these algorithms was compared and the results showed that the proposed CWT technique correctly classifies as ''double'' a large number of clicks that are recognized as ''single'' by the Myotis 3C.

  4. Time-Resolved Micro PIV in the Pivoting Area of the Triflo Mechanical Heart Valve.

    Science.gov (United States)

    Vennemann, Bernhard M; Rösgen, Thomas; Carrel, Thierry P; Obrist, Dominik

    2016-09-01

    The Lapeyre-Triflo FURTIVA valve aims at combining the favorable hemodynamics of bioprosthetic heart valves with the durability of mechanical heart valves (MHVs). The pivoting region of MHVs is hemodynamically of special interest as it may be a region of high shear stresses, combined with areas of flow stagnation. Here, platelets can be activated and may form a thrombus which in the most severe case can compromise leaflet mobility. In this study we set up an experiment to replicate the pulsatile flow in the aortic root and to study the flow in the pivoting region under physiological hemodynamic conditions (CO = 4.5 L/min / CO = 3.0 L/min, f = 60 BPM). It was found that the flow velocity in the pivoting region could reach values close to that of the bulk flow during systole. At the onset of diastole the three valve leaflets closed in a very synchronous manner within an average closing time of 55 ms which is much slower than what has been measured for traditional bileaflet MHVs. Hot spots for elevated viscous shear stresses were found at the flanges of the housing and the tips of the leaflet ears. Systolic VSS was maximal during mid-systole and reached levels of up to 40 Pa.

  5. Recellularization of decellularized heart valves: Progress toward the tissue-engineered heart valve.

    Science.gov (United States)

    VeDepo, Mitchell C; Detamore, Michael S; Hopkins, Richard A; Converse, Gabriel L

    2017-01-01

    The tissue-engineered heart valve portends a new era in the field of valve replacement. Decellularized heart valves are of great interest as a scaffold for the tissue-engineered heart valve due to their naturally bioactive composition, clinical relevance as a stand-alone implant, and partial recellularization in vivo. However, a significant challenge remains in realizing the tissue-engineered heart valve: assuring consistent recellularization of the entire valve leaflets by phenotypically appropriate cells. Many creative strategies have pursued complete biological valve recellularization; however, identifying the optimal recellularization method, including in situ or in vitro recellularization and chemical and/or mechanical conditioning, has proven difficult. Furthermore, while many studies have focused on individual parameters for increasing valve interstitial recellularization, a general understanding of the interacting dynamics is likely necessary to achieve success. Therefore, the purpose of this review is to explore and compare the various processing strategies used for the decellularization and subsequent recellularization of tissue-engineered heart valves.

  6. 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.

  7. Magnetic resonance imaging of prosthetic heart valves.

    Science.gov (United States)

    Soulen, R L; Budinger, T F; Higgins, C B

    1985-03-01

    To evaluate the safety of magnetic resonance (MR) imaging of prosthetic heart valves, nine different synthetic and tissue valves were studied ex vivo. Deflection was measured in 0.35-tesla (T) and 1.5-T superconducting magnets and at the edge of the bore of a 2.35-T electromagnet in field gradients of 5, 1.1, and 6.3 mT/cm, respectively. No valve deflected in the 0.35-T magnet; six synthetic valves deflected 0.25 degrees-3 degrees in the 1.5-T magnet; all valves deflected 1 degree-27 degrees at the edge of the 2.35-T magnet. Each valve was then submerged in a vial of water and the temperature was measured immediately before and after each of two spin-echo imaging sequences in the two superconducting magnets. No significant temperature rise followed exposure in either magnet. Image distortion varied from negligible to severe in both imagers; magnitude of distortion paralleled magnitude of deflection. These data suggest that patients with present-day prosthetic heart valves can be safely imaged in present-day MR imagers and that prosthesis-induced artifacts will not interfere with interpretation in most instances.

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

    Science.gov (United States)

    Weber, Benedikt; Scherman, Jacques; Emmert, Maximilian Y; Gruenenfelder, Juerg; Verbeek, Renier; Bracher, Mona; Black, Melanie; Kortsmit, Jeroen; Franz, Thomas; Schoenauer, Roman; Baumgartner, Laura; Brokopp, Chad; Agarkova, Irina; Wolint, Petra; Zund, Gregor; Falk, Volkmar; Zilla, Peter; Hoerstrup, Simon P

    2011-11-01

    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. Trileaflet heart valves were fabricated from non-woven biodegradable synthetic composite scaffolds and integrated into self-expanding nitinol stents. During the same intervention autologous bone marrow-derived mononuclear cells were harvested, seeded onto the scaffold matrix, and implanted transapically as pulmonary valve replacements into non-human primates (n = 6). The transapical implantations were successful in all animals and the overall procedure time from cell harvest to TEHV implantation was 118 ± 17 min. In vivo functionality assessed by echocardiography revealed preserved valvular structures and adequate functionality up to 4 weeks post implantation. Substantial cellular remodelling and in-growth into the scaffold materials resulted in layered, endothelialized tissues as visualized by histology and immunohistochemistry. Biomechanical analysis showed non-linear stress-strain curves of the leaflets, indicating replacement of the initial biodegradable matrix by living tissue. Here, we provide a novel concept demonstrating that heart valve tissue engineering based on a minimally invasive technique for both cell harvest and valve delivery as a one-step intervention is feasible in non-human primates. This innovative approach may overcome the limitations of contemporary surgical and interventional bioprosthetic heart valve prostheses.

  9. Association of warfarin therapy duration after bioprosthetic aortic valve replacement with risk of mortality, thromboembolic complications, and bleeding

    DEFF Research Database (Denmark)

    Mérie, Charlotte; Køber, Lars; Skov Olsen, Peter

    2012-01-01

    The need for anticoagulation after surgical aortic valve replacement (AVR) with biological prostheses is not well examined.......The need for anticoagulation after surgical aortic valve replacement (AVR) with biological prostheses is not well examined....

  10. 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.

  11. 21 CFR 870.3945 - Prosthetic heart valve sizer.

    Science.gov (United States)

    2010-04-01

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

  12. 21 CFR 870.3935 - Prosthetic heart valve holder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prosthetic heart valve holder. 870.3935 Section... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3935 Prosthetic heart valve holder. (a) Identification. A prosthetic heart valve holder is a device used to hold a...

  13. 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 thrombosis, the thrombus volume increased linearly with implant depth ( R 2 =0.7, P thrombosis is a multifactorial process involving foreign materials, patient-specific blood chemistry, and complex flow patterns, our study indicates that deployed THV geometry may have implications on the occurrence of thrombosis. In addition, a supraannular neosinus may reduce thrombosis risk because of reduced flow stasis. Although additional prospective studies are needed to further develop strategies for minimizing thrombus burden, these results may help identify patients at higher thrombosis risk and aid in the development of next-generation devices

  14. 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...... ((Equation is included in full-text article.)O2peak) or 6-minute walk test (6MWT). A composite endpoint of all-cause mortality and hospital admission due to myocardial infarction, stroke, heart failure, endocarditis, revascularization, or reoperation was used to assess the hazard ratio between CR attenders...

  15. Antithrombotic Treatment after Transcatheter Heart Valves Implant.

    Science.gov (United States)

    Sorrentino, Sabato; Giustino, Gennaro; Moalem, Kamilia; Indolfi, Ciro; Mehran, Roxana; Dangas, George D

    2018-02-01

    Transcatheter heart valve replacement technology was introduced as alternative to surgery for the growing high-risk profile population. Developed first, aortic valve replacement (TAVR) became a standard of care for patients with severe aortic stenosis at high operative risk, with a potential future use also for low-risk subjects. In the last decade, a multitude of transcatheter mitral valve replacement (TMVR) devices have been developed for the treatment of severe mitral regurgitation, with encouraging results coming from first-in-man and feasibility studies. As for biological surgical-type valves, transcatheter implanted valves still preserve the risk of thrombosis and embolic events and anticoagulation- or antiplatelet-based strategies are the most widely used options. Unfortunately, these last remain recommended on the basis of empirical or not widely validated evidence. Therefore, given the exponential rise of TAVR and TMVR procedures, it is important to identify the optimal antithrombotic strategies that best fit the risk of thromboembolic and bleeding events. Hereafter, this review evaluates the current guidelines, trials, and observational data discussing antithrombotic strategy after transcatheter aortic or mitral valve replacement. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  16. 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.

  17. Role of vortices in cavitation formation in the flow across a mechanical heart valve.

    Science.gov (United States)

    Li, Chi-Pei; Lu, Po-Chien; Liu, Jia-Shing; Lo, Chi-Wen; Hwang, Ned H

    2008-07-01

    Cavitation occurs during mechanical heart valve closure when the local pressure drops below vapor pressure. The formation of stable gas bubbles may result in gaseous emboli, and secondarily cause transient ischemic attacks or strokes. It is noted that instantaneous valve closure, occluder rebound and high-speed leakage flow generate vortices that promote low-pressure regions in favor of stable bubble formation; however, to date no studies have been conducted for the quantitative measurement and analysis of these vortices. A Björk-Shiley Monostrut (BSM) monoleaflet valve was placed in the mitral position of a pulsatile mock circulatory loop. Particle image velocimetry (PIV) and pico coulomb (PCB) pressure measurements were applied. Flow field measurements were carried out at t = -5, -3, -1, -0.5, 0 (valve closure), 0.3, 0.5, 0.75, 1.19, 1.44, 1.69, 1.94, 2, 2.19, 2.54, 2.79, 3.04, 3.29, 3.54, 5 and 10 ms. The vortices were quantitatively analyzed using the Rankine vortex model. A single counter-clockwise vortex was The instantaneous formation of cavitation bubbles at mechanical heart valve (MHV) closure, which subsequently damage blood cells and valve integrity, is a well-known and widely studied phenomenon (1-4). Contributing factors seem to include the water-hammer, squeeze flow and Venturi effects, all of which are short-lived. Both, Dauzat et al. (5) and Sliwka et al. (6) have detected high-intensity transient signals (HITS) with transcranial Doppler ultrasound in the carotid and cerebral arteries of MHV recipients, while Deklunder (7) observed clinical occurrences of cerebral gas emboli that were not seen with bioprosthetic valves. These detected over the major orifice, while a pair of counter-rotating vortices was found over the minor orifice. Velocity profiles were consistent with Rankine vortices. The vortex strength and magnitude of the pressure drop peaked shortly after initial occluder-housing impact and rapidly decreased after 0.5 ms, indicating viscous

  18. Pulse Duplicator Hydrodynamic Testing of Bioengineered Biological Heart Valves.

    Science.gov (United States)

    Buse, Eric E; Hilbert, Stephen L; Hopkins, Richard A; Converse, Gabriel L

    2016-12-01

    There are many heart valve replacements currently available on the market; however, these devices are not ideal for pediatric patients with congenital heart valve defects. Decellularized valve substitutes offer potential for improved clinical outcomes and require pre-clinical testing guidelines and testing systems suitable for non-crosslinked, biological heart valves. The objective of this study was to assess the hydrodynamic performance of intact, bioengineered pulmonary valves using a custom pulse duplicator capable of testing intact biological valved conduits. The mechanical behavior of valve associated sinus and arterial tissue was also evaluated under biaxial loading. Cryopreserved, decellularized, extracellular matrix (ECM) conditioned and glutaraldehyde fixed valves showed reduced pressure gradients and increased effective orifice area for decellularized and ECM conditioned valves. ECM conditioning resulted in increased elastic modulus but decreased stretch in circumferential and longitudinal directions under biaxial loading. Overall, decellularization and ECM conditioning did not compromise the scaffolds, which exhibited satisfactory bench top performance.

  19. 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)....

  20. Leaky valves : New operation improves the heart's pumping action

    NARCIS (Netherlands)

    Pistecky, P.; Havlik, P.; Van Kasteren, J.

    2003-01-01

    The action of any pump will start to decline when the valves no longer close properly. The same goes for the heart, the pump that maintains the circulation in our vascular system. Consequently, a major field of focus of open heart surgery is the repair or replacement of heart valves. Petr Havl a

  1. Carcinoid Heart Disease without Severe Tricuspid Valve Involvement.

    Science.gov (United States)

    Killu, Ammar M; Newman, Darrell B; Miranda, William R; Maleszewski, Joseph J; Pellikka, Patricia; Schaff, Hartzell V; Connolly, Heidi M

    2016-01-01

    Carcinoid syndrome causes a rare form of acquired valvular heart disease which typically occurs in the setting of liver metastases. In carcinoid-induced valvular heart disease, the tricuspid valve is almost universally affected; left-sided valve disease occurs infrequently in affected patients. Herein, we report 2 cases of carcinoid-induced valvular heart disease; one case had no evidence of tricuspid valve involvement despite severe involvement of all other valves, while the other case was without severe tricuspid valve involvement. © 2015 S. Karger AG, Basel.

  2. Tricuspid valve regurgitation after heart transplantation

    Science.gov (United States)

    Kwon, Murray H.

    2017-01-01

    Tricuspid valve regurgitation (TVR) in the orthotopic heart transplant (OHT) recipient is quite common and has varied clinical sequelae. In its severest forms, it can lead to right-sided failure symptoms indistinguishable from that seen in native heart TVR disease. While certain implantation techniques are widely recognized to reduce the risk of TVR in the cardiac allograft, concomitant tricuspid annuloplasty, while having advocates, is not currently accepted as a routinely established adjunct. Decisions to surgically correct TVR in the OHT recipient must be made carefully, as certain clinical scenarios have high risk of failure. Like in the native heart, anatomic etiologies typically have the greatest chances for success compared to functional etiologies. While repair options have been utilized, there is emerging data to support replacement as the more durable option. While mechanical prostheses are impractical in the heart transplant recipient, biologic valves offer the advantage of continued access to the right ventricle for biopsies in addition to acceptable durability in the low pressure system of the right side. PMID:28706871

  3. Use of cardiovascular magnetic resonance imaging for TAVR assessment in patients with bioprosthetic aortic valves: Comparison with computed tomography

    International Nuclear Information System (INIS)

    Quail, Michael A.; Nordmeyer, Johannes; Schievano, Silvia; Reinthaler, Markus; Mullen, Michael J.; Taylor, Andrew M.

    2012-01-01

    Purpose: Transcatheter aortic valve replacement (TAVR) has been successfully used to treat patients with failing aortic bioprostheses. Computed tomography (CT) is the usual method of pre-procedural imaging for TAVR in the native position; however, the optimal modality for valve-in-valve procedures has not been established. CT can assess intracardiac anatomy and is superior to cardiovascular magnetic resonance (CMR) in the assessment of coronary artery disease. However, CMR can provide superior haemodynamic information, does not carry the risk of ionising radiation, and may be performed without contrast in patients with renal insufficiency. In this study, we compared CT and CMR for the evaluation of TAVR in a small cohort of patients with existing aortic bioprostheses. Materials and methods: 21 patients with aortic bioprostheses were prospectively evaluated by CT and CMR, as pre-assessment for TAVR; agreement between measurements of aortic geometries was assessed. Results: 16/21 patients had aortic bioprostheses constructed with a metal ring, and 5/21 patients had a metal strut construction. Patients with metal struts had significant metal-artefact on CMR, which compromised image quality in this region. There was good agreement between CT and CMR measurements of aortic geometry. The mean difference (d) in annulus area-derived diameter was 0.5 mm (95% limits of agreement [L.A] 4.2 mm). There was good agreement between modalities for the cross-sectional area of the sinuses of valsalva (d 0.5 cm 2 , L.A 1.4 cm 2 ), sinotubular junction (d 0.9 cm 2 , L.A 1.5 cm 2 ), and ascending aorta (d 0.6 cm 2 , L.A 1.4 cm 2 ). In patients without metal struts, the left coronary artery height d was 0.7 mm and L.A 2.8 mm. Conclusions: Our analysis shows that CMR and CT measurements of aortic geometry show good agreement, including measurement of annulus size and coronary artery location, and thus provide the necessary anatomical information for valve-in-valve TAVR planning. However

  4. Use of cardiovascular magnetic resonance imaging for TAVR assessment in patients with bioprosthetic aortic valves: Comparison with computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Quail, Michael A., E-mail: m.quail@ucl.ac.uk [Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science and Great Ormond Street Hospital for Children, London (United Kingdom); Nordmeyer, Johannes [Department of Congenital Heart Disease and Paediatric Cardiology, Deutsches Herzzentrum Berlin, Berlin (Germany); Schievano, Silvia [Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science and Great Ormond Street Hospital for Children, London (United Kingdom); Reinthaler, Markus; Mullen, Michael J. [The Heart Hospital, University College Hospital and Institute of Cardiovascular Sciences, UCL, 16-18 Westmoreland Street, London (United Kingdom); Taylor, Andrew M. [Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science and Great Ormond Street Hospital for Children, London (United Kingdom)

    2012-12-15

    Purpose: Transcatheter aortic valve replacement (TAVR) has been successfully used to treat patients with failing aortic bioprostheses. Computed tomography (CT) is the usual method of pre-procedural imaging for TAVR in the native position; however, the optimal modality for valve-in-valve procedures has not been established. CT can assess intracardiac anatomy and is superior to cardiovascular magnetic resonance (CMR) in the assessment of coronary artery disease. However, CMR can provide superior haemodynamic information, does not carry the risk of ionising radiation, and may be performed without contrast in patients with renal insufficiency. In this study, we compared CT and CMR for the evaluation of TAVR in a small cohort of patients with existing aortic bioprostheses. Materials and methods: 21 patients with aortic bioprostheses were prospectively evaluated by CT and CMR, as pre-assessment for TAVR; agreement between measurements of aortic geometries was assessed. Results: 16/21 patients had aortic bioprostheses constructed with a metal ring, and 5/21 patients had a metal strut construction. Patients with metal struts had significant metal-artefact on CMR, which compromised image quality in this region. There was good agreement between CT and CMR measurements of aortic geometry. The mean difference (d) in annulus area-derived diameter was 0.5 mm (95% limits of agreement [L.A] 4.2 mm). There was good agreement between modalities for the cross-sectional area of the sinuses of valsalva (d 0.5 cm{sup 2}, L.A 1.4 cm{sup 2}), sinotubular junction (d 0.9 cm{sup 2}, L.A 1.5 cm{sup 2}), and ascending aorta (d 0.6 cm{sup 2}, L.A 1.4 cm{sup 2}). In patients without metal struts, the left coronary artery height d was 0.7 mm and L.A 2.8 mm. Conclusions: Our analysis shows that CMR and CT measurements of aortic geometry show good agreement, including measurement of annulus size and coronary artery location, and thus provide the necessary anatomical information for valve-in-valve

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

    Science.gov (United States)

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

    2018-01-23

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

  6. 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

  7. Tubular heart valves from decellularized engineered tissue.

    Science.gov (United States)

    Syedain, Zeeshan H; Meier, Lee A; Reimer, Jay M; Tranquillo, Robert T

    2013-12-01

    A novel tissue-engineered heart valve (TEHV) was fabricated from a decellularized tissue tube mounted on a frame with three struts, which upon back-pressure cause the tube to collapse into three coapting "leaflets." The tissue was completely biological, fabricated from ovine fibroblasts dispersed within a fibrin gel, compacted into a circumferentially aligned tube on a mandrel, and matured using a bioreactor system that applied cyclic distension. Following decellularization, the resulting tissue possessed tensile mechanical properties, mechanical anisotropy, and collagen content that were comparable to native pulmonary valve leaflets. When mounted on a custom frame and tested within a pulse duplicator system, the tubular TEHV displayed excellent function under both aortic and pulmonary conditions, with minimal regurgitant fractions and transvalvular pressure gradients at peak systole, as well as well as effective orifice areas exceeding those of current commercially available valve replacements. Short-term fatigue testing of one million cycles with pulmonary pressure gradients was conducted without significant change in mechanical properties and no observable macroscopic tissue deterioration. This study presents an attractive potential alternative to current tissue valve replacements due to its avoidance of chemical fixation and utilization of a tissue conducive to recellularization by host cell infiltration.

  8. Implantation and 30-Day Follow-Up on All 4 Valve Sizes Within the Portico Transcatheter Aortic Bioprosthetic Family

    DEFF Research Database (Denmark)

    Möllmann, Helge; Linke, Axel; Holzhey, David M

    2017-01-01

    to be at high surgical risk were recruited between December 2011 and September 2015 in this prospective, nonrandomized, multicenter study. Patients were implanted with the full range of Portico heart valves (23, 25, 27, and 29 mm) using the transfemoral approach. The primary endpoint was all-cause mortality...... valves implanted. All resheathing and repositioning attempts (n = 72) were successful. At 30 days, all-cause mortality was 3.6%. Procedural outcomes included disabling (major) stroke (3.2%), major vascular complications (7.2%), and permanent pacemaker implantation (13.5%). Compared with baseline, 75...

  9. High readmission rate after heart valve surgery

    DEFF Research Database (Denmark)

    Sibilitz, K L; Berg, S K; Thygesen, L C

    2015-01-01

    investigated. RESULTS: After valve surgery, the self-reported health was lower (Short Form-36 (SF-36) Physical Component Scale (PCS): 44.5 vs. 50.6 and Mental Component Scale (MCS): 51.9 vs. 55.0, pClinical signs......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...... of anxiety and depression were present in 13.6% and 13.8%, respectively (Hospital Anxiety and Depression Scale score≥8). Twelve months following discharge, 483 persons (56%) were readmitted. Readmission was associated with lower self-reported health (SF-36 PCS: 46.5 vs. 43.9, and MCS 52.2 vs. 50.7). Higher...

  10. Elucidating the Molecular-Level Events in Valvular Interstitial Cell Calcification to Improve the Design of Tissue-Engineered Heart Valves

    Science.gov (United States)

    Gu, Xiaoxiao

    Calcification is the leading cause of native and bioprosthetic heart valve failure, yet its etiology and progression remain poorly understood. Total valve replacement, which is both invasive and accompanied by numerous shortcomings, is commonly performed to replace stenotic valves, but there are currently no medical agents that are FDA-approved for the prevention of aortic valve disease progression. Tissue engineering offers an attractive alternative to current valve replacement options. Thus, there is a pressing need to: (1) better understand the progression of valve calcification, (2) develop more options for prevention and treatment of valve calcification, and (3) define the properties of appropriate scaffold environments that will support the growth of engineered valve tissue. In this thesis, we describe our plan to bring together these goals in cardiovascular medicine: we aim to identify differences between calcifying and non-calcifying valve cultures and then use this information to discover potential calcification inhibitors and define biomaterial environments that can be used to support either healthy or diseased valvular interstitial cell function.

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

    African Journals Online (AJOL)

    1973-01-27

    Jan 27, 1973 ... find a pathologic cause for some of the unexplained 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 ...

  12. Improved Pig Model to Evaluate Heart Valve Thrombosis.

    Science.gov (United States)

    Payanam Ramachandra, Umashankar; Shenoy, Sachin J; Arumugham, Sabareeswaran

    2016-09-01

    Although the sheep is the most acceptable animal model for heart valve evaluation, it has severe limitations for detecting heart valve thrombosis during preclinical studies. While the pig offers an alternative model and is better for detecting prosthetic valve thrombogenicity, it is not often used because of inadvertent valve thrombosis or bleeding complications. The study aim was to develop an improved pig model which can be used reliably to evaluate mechanical heart valve thrombogenicity. Mechanical heart valves were implanted in the mitral position of indigenous pigs administered aspirin-clopidogrel, and compared with similar valves implanted in control pigs to which no antiplatelet therapy had been administered. The pigs were observed for six months to study their overall survivability, inadvertent bleeding/valve thrombosis and pannus formation. The efficacy of aspirinclopidogrel on platelet aggregation and blood coagulation was also recorded and compared between test and control animals. In comparison to controls, pigs receiving anti-platelet therapy showed an overall better survivability, an absence of inadvertent valve thrombosis/ bleeding, and less obstructive pannus formation. Previously unreported inhibitory effects of aspirin-clopidogrel on the intrinsic pathway of blood coagulation were also observed in the pig model. Notably, with aspirin-clopidogrel therapy inadvertent thrombus formation or bleeding can be prevented. The newly developed pig model can be successfully used to evaluate heart valve thrombosis following chronic orthotopic valve implantation. The model may also be utilized to evaluate other bloodcontacting implantable devices.

  13. Current Challenges in Translating Tissue-Engineered Heart Valves.

    Science.gov (United States)

    Stassen, O M J A; Muylaert, D E P; Bouten, C V C; Hjortnaes, J

    2017-09-01

    Heart valve disease is a major health burden, treated by either valve repair or valve replacement, depending on the affected valve. Nearly 300,000 valve replacements are performed worldwide per year. Valve replacement is lifesaving, but not without complications. The in situ tissue-engineered heart valve is a promising alternative to current treatments, but the translation of this novel technology to the clinic still faces several challenges. These challenges originate from the variety encountered in the patient population, the conversion of an implant into a living tissue, the highly mechanical nature of the heart valve, the complex homeostatic tissue that has to be reached at the end stage of the regenerating heart valve, and all the biomaterial properties that can be controlled to obtain this tissue. Many of these challenges are multidimensional and multiscalar, and both the macroscopic properties of the complete heart valve and the microscopic properties of the patient's cells interacting with the materials have to be optimal. Using newly developed in vitro models, or bioreactors, where variables of interest can be controlled tightly and complex mixtures of cell populations similar to those encountered in the regenerating valve can be cultured, it is likely that the challenges can be overcome.

  14. A robust correlation method to detect heterogeneous heart valve symptoms

    Science.gov (United States)

    Suboh, Mohd Zubir; Mansor, Muhammad Naufal; Junoh, Ahmad Kadri; Daud, Wan Suhana Wan; Muhamad, Wan Zuki Azman Wan; Idris, Azrini

    2015-05-01

    Heart valve disease affects a large number of patients. During the past decade, major advances have occurred in diagnostic techniques of heart valve disease. In this paper, we present an alternative method in classifying heart valve disease using correlation analysis and neural network classifier based on heart sound signal. The heart sound signals used in this study were taken from heart sound manipulator software. First, the signal was converted into frequency domain. Then, power spectrum of the sample is determined and cross-correlated with a reference sample (also in power spectrum form) to get different pattern of correlation plot. Seven different heart sounds of normal and other abnormal sounds from heart valve disease were classified into their classes. The result shows that 98.70% of the samples had been correctly classified by the system.

  15. The tricuspid valve in adult congenital heart disease.

    Science.gov (United States)

    Ginns, Jonathan; Ammash, Naser; Bernier, Pierre-Luc

    2014-01-01

    The tricuspid valve is frequently affected in adults with congenital heart disease but is also frequently overlooked. Disease of this valve can occur primarily or develop secondary to changes in the right ventricle caused by other disease states. The embryology and anatomy of the tricuspid valve are important to understanding pathogenesis of valve dysfunction in congenital heart disease. Clinical findings can be subtle. Multimodality imaging may be necessary to fully assess the cause and impact of tricuspid valve lesions. More research is needed in pathophysiology, imaging, and treatment in this area. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Influence of Tricuspid Bioprosthetic Mitral Valve Orientation Regarding the Flow Field Inside the Left Ventricle: In Vitro Hydrodynamic Characterization Based on 2D PIV Measurements.

    Science.gov (United States)

    Bazan, Ovandir; Ortiz, Jayme P; Fukumasu, Newton K; Pacifico, Antonio L; Yanagihara, Jurandir I

    2016-02-01

    The flow patterns of a prosthetic heart valve in the aortic or mitral position can change according to its type and orientation. This work describes the use of 2D particle image velocimetry (PIV) applied to the in vitro flow fields characterization inside the upper part of a left ventricular model at various heart rates and as a function of two orientations of stented tricuspid mitral bioprostheses. In the ventricular model, each mitral bioprosthesis (27 and 31 mm diameter) was installed in two orientations, rotated by 180°, while the aortic bileaflet mechanical valve (27 mm diameter) remained in a fixed orientation. The results (N = 50) showed changes in the intraventricular flow fields according to the mitral bioprostheses positioning. Also, changes in the aortic upstream velocity profiles were noticed as a function of mitral orientations. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  17. Tissue-engineered heart valve: future of cardiac surgery.

    Science.gov (United States)

    Rippel, Radoslaw A; Ghanbari, Hossein; Seifalian, Alexander M

    2012-07-01

    Heart valve disease is currently a growing problem, and demand for heart valve replacement is predicted to increase significantly in the future. Existing "gold standard" mechanical and biological prosthesis offers survival at a cost of significantly increased risks of complications. Mechanical valves may cause hemorrhage and thromboembolism, whereas biologic valves are prone to fibrosis, calcification, degeneration, and immunogenic complications. A literature search was performed to identify all relevant studies relating to tissue-engineered heart valve in life sciences using the PubMed and ISI Web of Knowledge databases. Tissue engineering is a new, emerging alternative, which is reviewed in this paper. To produce a fully functional heart valve using tissue engineering, an appropriate scaffold needs to be seeded using carefully selected cells and proliferated under conditions that resemble the environment of a natural human heart valve. Bioscaffold, synthetic materials, and preseeded composites are three common approaches of scaffold formation. All available evidence suggests that synthetic scaffolds are the most suitable material for valve scaffold formation. Different cell sources of stem cells were used with variable results. Mesenchymal stem cells, fibroblasts, myofibroblasts, and umbilical blood stem cells are used in vitro tissue engineering of heart valve. Alternatively scaffold may be implanted and then autoseeded in vivo by circulating endothelial progenitor cells or primitive circulating cells from patient's blood. For that purpose, synthetic heart valves were developed. Tissue engineering is currently the only technology in the field with the potential for the creation of tissues analogous to a native human heart valve, with longer sustainability, and fever side effects. Although there is still a long way to go, tissue-engineered heart valves have the capability to revolutionize cardiac surgery of the future.

  18. Tissue engineering of autologous heart valves: a focused update.

    Science.gov (United States)

    Le Huu, Alice; Shum-Tim, Dominique

    2014-01-01

    The prevalence of valvular heart disease is expected to increase in the coming decades, with an associated rise in valve-related surgeries. Current options for valve prostheses remain limited, essentially confined to mechanical or biological valves. Neither selection provides an optimal balance between structural integrity and associated morbidity. Mechanical valves offer exceptional durability coupled with a considerable risk of thrombogenesis. Conversely, a biological prosthesis affords freedom from anticoagulation, but with a truncated valve lifespan. Tissue-engineered heart valves have been touted as a solution to this dilemma, by offering an immunopriviledged prosthesis combined with resistance from degeneration and the potential to grow. Although the reality of commercially available tissue-engineered heart valves remains distant, this article will highlight the cellular and clinical advancements in recent years.

  19. [Tissue engineering of heart valves: new opportunities and challenges].

    Science.gov (United States)

    Bobylev, D O; Chebotar', S; Tudorake, I; Khaverikh, A

    2011-01-01

    Replacement of heart valves appears to be prevailing method of surgical correction of end stage valvular heart defects. Main drawback of contemporary artificial valves is lack of growth, potential for remodeling, and inclination to degeneration. To overcome these limitations the modern science in the last decade focuses on tissue engineering of valves as an alternative to their prostheses. Basic idea of the technique is the use of decellularized xenogenic allogenic matrix or biopolymers seeded with autologous cells under special conditions created in bioreactor. This literature review is devoted to a novel direction in experimental cardiosurgery - tissue engineering of heart valves which in a unique way combines biological, engineering, and technological achievements.

  20. 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

  1. Scaffolds for tissue engineering of cardiac valves.

    Science.gov (United States)

    Jana, S; Tefft, B J; Spoon, D B; Simari, R D

    2014-07-01

    Tissue engineered heart valves offer a promising alternative for the replacement of diseased heart valves avoiding the limitations faced with currently available bioprosthetic and mechanical heart valves. In the paradigm of tissue engineering, a three-dimensional platform - the so-called scaffold - is essential for cell proliferation, growth and differentiation, as well as the ultimate generation of a functional tissue. A foundation for success in heart valve tissue engineering is a recapitulation of the complex design and diverse mechanical properties of a native valve. This article reviews technological details of the scaffolds that have been applied to date in heart valve tissue engineering research. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  2. 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...

  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. Bioreactors for development of tissue engineered heart valves.

    Science.gov (United States)

    Berry, Joel L; Steen, Julie A; Koudy Williams, J; Jordan, James E; Atala, Anthony; Yoo, James J

    2010-11-01

    Millions of people worldwide are diagnosed each year with valvular heart disease, resulting in hundreds of thousands of valve replacement operations. Prosthetic valve replacements are designed to correct narrowing or backflow through the valvular orifice. Although commonly used, these therapies have serious disadvantages including morbidity associated with long-term anticoagulation and limited durability necessitating repeat operations. The ideal substitute would be widely available and technically implantable for most cardiac surgeons, have normal hemodynamic performance, low risk for structural degeneration, thrombo-embolism and endocarditis, and growth potential for pediatric patients. Tissue engineered heart valves hold promise as a viable substitute to outperform existing valve replacements. An essential component to the development of tissue engineered heart valves is a bioreactor. It is inside the bioreactor that the scaffold and cells are gradually conditioned to the biochemical and mechanical environment of the valve to be replaced.

  5. Biomechanical properties of native and tissue engineered heart valve constructs.

    Science.gov (United States)

    Hasan, Anwarul; Ragaert, Kim; Swieszkowski, Wojciech; Selimović, Seila; Paul, Arghya; Camci-Unal, Gulden; Mofrad, Mohammad R K; Khademhosseini, Ali

    2014-06-27

    Due to the increasing number of heart valve diseases, there is an urgent clinical need for off-the-shelf tissue engineered heart valves. While significant progress has been made toward improving the design and performance of both mechanical and tissue engineered heart valves (TEHVs), a human implantable, functional, and viable TEHV has remained elusive. In animal studies so far, the implanted TEHVs have failed to survive more than a few months after transplantation due to insufficient mechanical properties. Therefore, the success of future heart valve tissue engineering approaches depends on the ability of the TEHV to mimic and maintain the functional and mechanical properties of the native heart valves. However, aside from some tensile quasistatic data and flexural or bending properties, detailed mechanical properties such as dynamic fatigue, creep behavior, and viscoelastic properties of heart valves are still poorly understood. The need for better understanding and more detailed characterization of mechanical properties of tissue engineered, as well as native heart valve constructs is thus evident. In the current review we aim to present an overview of the current understanding of the mechanical properties of human and common animal model heart valves. The relevant data on both native and tissue engineered heart valve constructs have been compiled and analyzed to help in defining the target ranges for mechanical properties of TEHV constructs, particularly for the aortic and the pulmonary valves. We conclude with a summary of perspectives on the future work on better understanding of the mechanical properties of TEHV constructs. © 2013 Published by Elsevier Ltd.

  6. 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

  7. 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.

  8. Exercise-based cardiac rehabilitation after heart valve surgery

    DEFF Research Database (Denmark)

    Hansen, T B; Zwisler, A D; 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...... expensive outpatient visits. Further studies should investigate the benefits of CR to heart valve surgery patients as part of a formal cost-utility analysis....

  9. Automatic measuring of quality criteria for heart valves

    Science.gov (United States)

    Condurache, Alexandru Paul; Hahn, Tobias; Hofmann, Ulrich G.; Scharfschwerdt, Michael; Misfeld, Martin; Aach, Til

    2007-03-01

    Patients suffering from a heart valve deficiency are often treated by replacing the valve with an artificial or biological implant. In case of biological implants, the use of porcine heart valves is common. Quality assessment and inspection methods are mandatory to supply the patients (and also medical research) with only the best such xenograft implants thus reducing the number of follow-up surgeries to replace worn-up valves. We describe an approach for automatic in-vitro evaluation of prosthetic heart valves in an artificial circulation system. We show how to measure the orifice area during a heart cycle to obtain an orifice curve. Different quality parameters are then estimated on such curves.

  10. Impact of prosthesis-patient mismatch on the regression of secondary mitral regurgitation after isolated aortic valve replacement with a bioprosthetic valve in patients with severe aortic stenosis.

    Science.gov (United States)

    Angeloni, Emiliano; Melina, Giovanni; Pibarot, Philippe; Benedetto, Umberto; Refice, Simone; Ciavarella, Giuseppino M; Roscitano, Antonino; Sinatra, Riccardo; Pepper, John R

    2012-01-01

    Secondary mitral regurgitation (SMR) is generally reduced after isolated aortic valve replacement (AVR), but there is important interindividual variability in the magnitude of this reduction. Prosthesis-patient mismatch (PPM) may hinder normalization of left ventricular geometry and pressure overload following AVR, therefore we aimed to investigate the relationship between PPM and regression of SMR following AVR for aortic valve stenosis. A total of 419 patients with AS who underwent isolated AVR at 2 institutions and presenting moderate SMR (mitral regurgitant volume 30 to 45 mL/beat) not considered for surgical correction were included in this study. Clinical and echocardiographic follow-up were completed at a median follow-up time of 37 months. PPM was defined as an indexed effective orifice area ≤0.85 cm(2)/m(2) and was found in 170/419 patients (40.6%). There were no significant differences in baseline and operative characteristics between patients with or without PPM. Patients with PPM had less regression of SMR following AVR compared with those with no PPM (change in mitral regurgitant volume: -11±4 versus -17±5 mL, respectively; Pregression model, which showed indexed effective orifice area (Pregression of SMR following AVR. This unfavorable effect was associated with worse functional capacity. These findings emphasize the importance of operative strategies aiming to prevent PPM in patients with aortic valve stenosis and concomitant SMR.

  11. 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.

  12. Biocompatibility Issue Of Tissue Engineered Heart Valves

    Directory of Open Access Journals (Sweden)

    Wilczek P.

    2015-09-01

    Full Text Available Tissue engineering is a new field of knowledge which creates the possibilities for producing bioactive cardiac prostheses that will characterize by biomechanical and morphological properties similar to native tissue. It is expected that it will be characterized by high durability, which is very important from the social and clinical point of view. The aim of the study was to compare the cytotoxic effect of enzymatic and detergent acellularization methods commonly used for the biological scaffold preparation. It seems that the use of enzymatic methods, allows efficient donor cells removal while maintaining the ability to autologous cell seeding. Heart valves bioprosthesis created using these techniques, may be a good alternative to the currently used prostheses.

  13. 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....

  14. 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.

  15. Prosthetic heart valve evaluation by magnetic resonance imaging

    OpenAIRE

    Hasenkam, J. Michael; Ringgaard, Steffen; Houlind, Kim; Botnar, René M.; Stødkilde-Jørgensen, Hans; Boesiger, Peter; Pedersen, Erik Morre

    2017-01-01

    Objective: To evaluate the potential of magnetic resonance imaging (MRI) for evaluation of velocity fields downstream of prosthetic aortic valves. Furthermore, to provide comparative data from bileaflet aortic valve prostheses in vitro and in patients. Methods: A pulsatile flow loop was set up in a 7.0 Tesla MRI scanner to study fluid velocity data downstream of a 25 mm aortic bileaflet heart valve prosthesis. Three dimensional surface plots of velocity fields were displayed. In six NYHA clas...

  16. Gal-knockout bioprostheses exhibit less immune stimulation compared to standard biological heart valves.

    Science.gov (United States)

    McGregor, Christopher G A; Kogelberg, Heide; Vlasin, Michal; Byrne, Guerard W

    2013-05-01

    Current biological heart valves (BHVs) contain the major xenogeneic antigen Gal. Recipient anti-Gal antibody binding to such an implanted BHV may contribute to valve degeneration. The study aim was to compare, by implantation in non-human primates, the immune consequences of BHVs from Gal-positive wild-type (WT) pigs and those from alpha-galactosyltransferase knockout (GTKO) pigs. Recipients were immunized prior to implant with keyhole limpet hemocyanin (KLH) conjugated to alphaGal to match the anti-Gal levels and isotypes found in humans. Stented glutaraldehyde-fixed BHVs from WT (n = 4) and GTKO (n = 3) pigs were commercially manufactured and implanted in the mitral position in non-human primates. Recipients were treated with enoxaparin (1 mg/kg b.i.d.) for five weeks which was tapered, and then discontinued. Serum antibody levels to Gal and KLH were measured using ELISA. Overall anti-Gal and anti-KLH antibody levels were decreased in both WT and GTKO BHV recipients after implantation. Serum anti-Gal IgG levels in GTKO BHV recipients fell rapidly within one month, matching the loss of anti-KLH reactivity. There was no significant difference in retention of anti-KLH antibody between the groups. WT BHV recipients retained significantly elevated levels of anti-Gal IgG during the first year post implant. Area under the curve analysis showed that anti-Gal IgG was significantly increased in the WT BHV group compared to GTKO BHV recipients (p < 0.01). Persistent and significantly (p < 0.01) elevated levels of anti-Gal IgG were observed in WT but not GTKO BHV non-human primate recipients, and indicated a continuing BHV-specific immune stimulation to the alphaGal antigen. These data support the hypothesis that the clinical use of Gal-positive xenogeneic bioprosthetic materials can induce an anti-Gal antibody response. Bioprosthetic devices prepared from GTKO pig tissue would eliminate immune stimulation to this major xenoreactive antigen, which may reduce the potential of

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

    African Journals Online (AJOL)

    1973-01-27

    Jan 27, 1973 ... could be found, even at autopsy. These latter deaths were regarded as being due to arrhythmia. The hospital mortality rate was 14% for mitral valve replacement with the vcr mitral valve prosthesis.' The major comp- lication was systemic embolism. A frequent autopsy finding in hearts which have recently ...

  18. 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.

  19. Recognizing the Symptoms of Worsening Heart Valve Disease

    Science.gov (United States)

    ... become short of breath? Is it walking three miles? Or has that three mile distance gotten shorter and shorter over time so ... her life depended on it. This content was last reviewed May 2016. Heart Valve Problems and Disease • ...

  20. Transcatheter implantation of homologous "off-the-shelf" tissue-engineered heart valves with self-repair capacity: long-term functionality and rapid in vivo remodeling in sheep.

    Science.gov (United States)

    Driessen-Mol, Anita; Emmert, Maximilian Y; Dijkman, Petra E; Frese, Laura; Sanders, Bart; Weber, Benedikt; Cesarovic, Nikola; Sidler, Michele; Leenders, Jori; Jenni, Rolf; Grünenfelder, Jürg; Falk, Volkmar; Baaijens, Frank P T; Hoerstrup, Simon P

    2014-04-08

    This study sought to evaluate long-term in vivo functionality, host cell repopulation, and remodeling of "off-the-shelf" tissue engineered transcatheter homologous heart valves. Transcatheter valve implantation has emerged as a valid alternative to conventional surgery, in particular for elderly high-risk patients. However, currently used bioprosthetic transcatheter valves are prone to progressive dysfunctional degeneration, limiting their use in younger patients. To overcome these limitations, the concept of tissue engineered heart valves with self-repair capacity has been introduced as next-generation technology. In vivo functionality, host cell repopulation, and matrix remodeling of homologous transcatheter tissue-engineered heart valves (TEHVs) was evaluated up to 24 weeks as pulmonary valve replacements (transapical access) in sheep (n = 12). As a control, tissue composition and structure were analyzed in identical not implanted TEHVs (n = 5). Transcatheter implantation was successful in all animals. Valve functionality was excellent displaying sufficient leaflet motion and coaptation with only minor paravalvular leakage in some animals. Mild central regurgitation was detected after 8 weeks, increasing to moderate after 24 weeks, correlating to a compromised leaflet coaptation. Mean and peak transvalvular pressure gradients were 4.4 ± 1.6 mm Hg and 9.7 ± 3.0 mm Hg, respectively. Significant matrix remodeling was observed in the entire valve and corresponded with the rate of host cell repopulation. For the first time, the feasibility and long-term functionality of transcatheter-based homologous off-the-shelf tissue engineered heart valves are demonstrated in a relevant pre-clinical model. Such engineered heart valves may represent an interesting alternative to current prostheses because of their rapid cellular repopulation, tissue remodeling, and therewith self-repair capacity. The concept of homologous off-the-shelf tissue engineered heart valves may

  1. Tissue-engineered heart valves: intra-operative protocol.

    Science.gov (United States)

    Gallo, Michele; Bianco, Roberto; Bottio, Tomaso; Naso, Filippo; Franci, Paolo; Zanella, Fabio; Perona, Giovanni; Busetto, Roberto; Spina, Michele; Gandaglia, Alessandro; Gerosa, Gino

    2013-08-01

    Tissue engineering of heart valves investigates the possibility to create a fully compatible and biomimetic graft able to provide host cell repopulation like the native living valve. Decellularized aortic and pulmonary valves and synthetic polymers have been used to promote the creation of a native-like scaffold suitable to be colonized by cells either in vitro, in dynamic bioreactors or in vivo using different animal models. The herein presented research provides the intra-operative protocol and details of surgical technique. Porcine aortic valve conduits were decellularized and implanted in the right ventricular outflow tract of Vietnamese pigs.

  2. Glycosaminoglycan entrapment by fibrin in engineered heart valve tissues.

    Science.gov (United States)

    Alfonso, Abraham R; Rath, Sasmita; Rafiee, Parvin; Hernandez-Espino, Mario; Din, Mahreen; George, Florence; Ramaswamy, Sharan

    2013-09-01

    Tissue engineered heart valves (TEHVs) may provide a permanent solution to congenital heart valve disease by permitting somatic valve growth in the pediatric patient. However, to date, TEHV studies have focused primarily on collagen, the dominant component of valve extracellular matrix (ECM). Temporal decreases in other ECM components, such as the glycosaminoglycans (GAGs), generally decrease as cells produce more collagen under mechanically loaded states; nevertheless, GAGs represent a key component of the valve ECM, providing structural stability and hydration to the leaflets. In an effort to retain GAGs within the engineered constructs, here we investigated the utility of the protein fibrin in combination with a valve-like, cyclic flexure and steady flow (flex-flow) mechanical conditioning culture process using adult human periodontal ligament cells (PLCs). We found both fibrin and flex-flow mechanical components to be independently significant (pengineered tissues. In addition, the interaction of fibrin with flex-flow was found to be significant in the case of collagen; specifically, the combination of these environments promoted PLC collagen production resulting in a significant difference compared to dynamic and statically cultured specimens without fibrin. Histological examination revealed that the GAGs were retained by fibrin entrapment and adhesion, which were subsequently confirmed by additional experiments on native valve tissues. We conclude that fibrin in the flex-flow culture of engineered heart valve tissues: (i) augments PLC-derived collagen production; and (ii) enhances retention of GAGs within the developing ECM. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. 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.

  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. Fluid Dynamics of the Heart and its Valves

    Science.gov (United States)

    Peskin, Charles S.

    1997-11-01

    The fluid dynamics of the heart involve the interaction of blood, a viscous incompressible fluid, with the flexible, elastic, fiber-reinforced heart valve leaflets that are immersed in that fluid. Neither the fluid motion nor the valve leaflet motion are known in advance: both must be computed simultaneously by solving their coupled equations of motion. This can be done by the immersed boundary method(Peskin CS and McQueen DM: A general method for the computer simulation of biological systems interacting with fluids. In: Biological Fluid Dynamics (Ellington CP and Pedley TJ, eds.), The Company of Biologists Limited, Cambridge UK, 1995, pp. 265-276.), which can be extended to incorporate the contractile fiber architecture of the muscular heart walls as well as the valve leaflets and the blood. In this way we arrive at a three-dimensional computer model of the heart(Peskin CS and McQueen DM: Fluid dynamics of the heart and its valves. In: Case Studies in Mathematical Modeling: Ecology, Physiology, and Cell Biology (Othmer HG, Adler FR, Lewis MA, and Dallon JC, eds.), Prentice-Hall, Englewood Cliffs NJ, 1996, pp. 309-337.), which can be used as a test chamber for the design of prosthetic cardiac valves, and also to study the function of the heart in health and in disease. Numerical solutions of the equations of cardiac fluid dynamics obtained by the immersed boundary method will be presented in the form of a video animation of the beating heart.

  6. Heart Valve Structure and Function in Development and Disease

    Science.gov (United States)

    Hinton, Robert B.; Yutzey, Katherine E.

    2014-01-01

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

  7. 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.

  8. 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

    2015-11-01

    Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy; the latter display better fluid dynamic behavior but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the hemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of 2 groups of newly developed supra-annular, trileaflet prosthetic heart valves made from styrenic block copolymers (SBC): Poli-Valves. 2 types of Poli-Valves made of SBC and differing in polystyrene fraction content were tested under continuous and pulsatile flow conditions as prescribed by ISO 5840 Standard. A pulse duplicator designed ad hoc 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 behavior of the valve. Both types of Poli-Valves met the minimum requirements in terms of regurgitation and EOA as specified by the ISO 5840 Standard. Results were compared with 5 mechanical heart valves (MHVs) and 5 tissue heart valves (THVs), currently available on the market. Based on these results, PHVs based on styrenic block copolymers, as are Poli-Valves, can be considered a promising alternative for heart valve replacement in the near future.

  9. Role of CT in patients with prosthetic heart valves

    NARCIS (Netherlands)

    Suchá, D.

    2016-01-01

    Valvular heart disease accounts for a substantial part of the cardiovascular disease worldwide with an estimated prevalence of 2.5% in the Western population aged <65 years and over 13% in the population aged >75 years. Surgical prosthetic heart valve (PHV) replacement is the indicated therapy for

  10. Pediatric tubular pulmonary heart valve from decellularized engineered tissue tubes.

    Science.gov (United States)

    Reimer, Jay M; Syedain, Zeeshan H; Haynie, Bee H T; Tranquillo, Robert T

    2015-09-01

    Pediatric patients account for a small portion of the heart valve replacements performed, but a pediatric pulmonary valve replacement with growth potential remains an unmet clinical need. Herein we report the first tubular heart valve made from two decellularized, engineered tissue tubes attached with absorbable sutures, which can meet this need, in principle. Engineered tissue tubes were fabricated by allowing ovine dermal fibroblasts to replace a sacrificial fibrin gel with an aligned, cell-produced collagenous matrix, which was subsequently decellularized. Previously, these engineered tubes became extensively recellularized following implantation into the sheep femoral artery. Thus, a tubular valve made from these tubes may be amenable to recellularization and, ideally, somatic growth. The suture line pattern generated three equi-spaced leaflets in the inner tube, which collapsed inward when exposed to back pressure, per tubular valve design. Valve testing was performed in a pulse duplicator system equipped with a secondary flow loop to allow for root distention. All tissue-engineered valves exhibited full leaflet opening and closing, minimal regurgitation (Valve performance was maintained under various trans-root pressure gradients and no tissue damage was evident after 2 million cycles of fatigue testing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Tissue-Engineered Heart Valves: A Call for Mechanistic Studies.

    Science.gov (United States)

    Blum, Kevin M; Drews, Joseph D; Breuer, Christopher K

    2018-02-13

    Heart valve disease carries a substantial risk of morbidity and mortality. Outcomes are significantly improved by valve replacement, but currently available mechanical and biological replacement valves are associated with complications of their own. Mechanical valves have a high rate of thromboembolism and require lifelong anticoagulation. Biological prosthetic valves have a much shorter lifespan, and they are prone to tearing and degradation. Both types of valves lack the capacity for growth, making them particularly problematic in pediatric patients. Tissue engineering has the potential to overcome these challenges by creating a neovalve composed of native tissue that is capable of growth and remodeling. The first tissue-engineered heart valve (TEHV) was created more than 20 years ago in an ovine model, and the technology has been advanced to clinical trials in the intervening decades. Some TEHVs have had clinical success, whereas others have failed, with structural degeneration resulting in patient deaths. The etiologies of these complications are poorly understood because much of the research in this field has been performed in large animals and humans, and, therefore, there are few studies of the mechanisms of neotissue formation. This review examines the need for a TEHV to treat pediatric patients with valve disease, the history of TEHVs, and a future that would benefit from extension of the reverse translational trend in this field to include small animal studies.

  12. 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.

  13. Prosthetic heart valve evaluation by magnetic resonance imaging.

    Science.gov (United States)

    Hasenkam, J M; Ringgaard, S; Houlind, K; Botnar, R M; Stødkilde-Jørgensen, H; Boesiger, P; Pedersen, E M

    1999-09-01

    To evaluate the potential of magnetic resonance imaging (MRI) for evaluation of velocity fields downstream of prosthetic aortic valves. Furthermore, to provide comparative data from bileaflet aortic valve prostheses in vitro and in patients. A pulsatile flow loop was set up in a 7.0 Tesla MRI scanner to study fluid velocity data downstream of a 25 mm aortic bileaflet heart valve prosthesis. Three dimensional surface plots of velocity fields were displayed. In six NYHA class I patients blood velocity profiles were studied downstream of their St. Jude Medical aortic valves using a 1.5 Tesla MRI whole-body scanner. Blood velocity data were displayed as mentioned above. Fluid velocity profiles obtained from in vitro studies 0.25 valve diameter downstream of the valve exhibited significant details about the cross sectional distribution of fluid velocities. This distribution completely reflected the valve design. Blood velocity profiles in humans were considerably smoother and in some cases skewed with the highest velocities toward the anterior-right ascending aortic wall. Display and interpretation of fluid and blood velocity data obtained downstream of prosthetic valves is feasible both in vitro and in vivo using the MRI technique. An in vitro model with a straight tube and the test valve oriented orthogonally to the long axis of the test tube does not entail fluid velocity profiles which are compatible to those obtained from humans, probably due to the much more complex human geometry, and variable alignment of the valve with the ascending aorta. With the steadily improving quality of MRI scanners this technique has significant potential for comparative in vitro and in vivo hemodynamic evaluation of heart valves.

  14. Dynamic Heterogeneity of the Heart Valve Interstitial Cell Population in Mitral Valve Health and Disease

    Directory of Open Access Journals (Sweden)

    Tori E. Horne

    2015-08-01

    Full Text Available The heart valve interstitial cell (VIC population is dynamic and thought to mediate lay down and maintenance of the tri-laminar extracellular matrix (ECM structure within the developing and mature valve throughout life. Disturbances in the contribution and distribution of valve ECM components are detrimental to biomechanical function and associated with disease. This pathological process is associated with activation of resident VICs that in the absence of disease reside as quiescent cells. While these paradigms have been long standing, characterization of this abundant and ever-changing valve cell population is incomplete. Here we examine the expression pattern of Smooth muscle α-actin, Periostin, Twist1 and Vimentin in cultured VICs, heart valves from healthy embryonic, postnatal and adult mice, as well as mature valves from human patients and established mouse models of disease. We show that the VIC population is highly heterogeneous and phenotypes are dependent on age, species, location, and disease state. Furthermore, we identify phenotypic diversity across common models of mitral valve disease. These studies significantly contribute to characterizing the VIC population in health and disease and provide insights into the cellular dynamics that maintain valve structure in healthy adults and mediate pathologic remodeling in disease states.

  15. Progress in developing a living human tissue-engineered tri-leaflet heart valve assembled from tissue produced by the self-assembly approach.

    Science.gov (United States)

    Dubé, Jean; Bourget, Jean-Michel; Gauvin, Robert; Lafrance, Hugues; Roberge, Charles J; Auger, François A; Germain, Lucie

    2014-08-01

    The aortic heart valve is constantly subjected to pulsatile flow and pressure gradients which, associated with cardiovascular risk factors and abnormal hemodynamics (i.e. altered wall shear stress), can cause stenosis and calcification of the leaflets and result in valve malfunction and impaired circulation. Available options for valve replacement include homograft, allogenic or xenogenic graft as well as the implantation of a mechanical valve. A tissue-engineered heart valve containing living autologous cells would represent an alternative option, particularly for pediatric patients, but still needs to be developed. The present study was designed to demonstrate the feasibility of using a living tissue sheet produced by the self-assembly method, to replace the bovine pericardium currently used for the reconstruction of a stented human heart valve. In this study, human fibroblasts were cultured in the presence of sodium ascorbate to produce tissue sheets. These sheets were superimposed to create a thick construct. Tissue pieces were cut from these constructs and assembled together on a stent, based on techniques used for commercially available replacement valves. Histology and transmission electron microscopy analysis showed that the fibroblasts were embedded in a dense extracellular matrix produced in vitro. The mechanical properties measured were consistent with the fact that the engineered tissue was resistant and could be cut, sutured and assembled on a wire frame typically used in bioprosthetic valve assembly. After a culture period in vitro, the construct was cohesive and did not disrupt or disassemble. The tissue engineered heart valve was stimulated in a pulsatile flow bioreactor and was able to sustain multiple duty cycles. This prototype of a tissue-engineered heart valve containing cells embedded in their own extracellular matrix and sewn on a wire frame has the potential to be strong enough to support physiological stress. The next step will be to test

  16. The echocardiography of replacement heart valves

    Directory of Open Access Journals (Sweden)

    John B Chambers

    2016-10-01

    Full Text Available This is a practical description of how replacement valves are assessed using echocardiography. Normal transthoracic appearances including normal variants are described. The problem of differentiating normal function, patient–prosthesis mismatch and pathological obstruction in aortic replacement valves with high gradients is discussed. Obstruction and abnormal regurgitation is described for valves in the aortic, mitral and right-sided positions and when to use echocardiography in suspected infective endocarditis. The roles of transoesophageal and stress echocardiography are described and finally when other imaging techniques may be useful.

  17. The echocardiography of replacement heart valves.

    Science.gov (United States)

    Chambers, John B

    2016-09-01

    This is a practical description of how replacement valves are assessed using echocardiography. Normal transthoracic appearances including normal variants are described. The problem of differentiating normal function, patient-prosthesis mismatch and pathological obstruction in aortic replacement valves with high gradients is discussed. Obstruction and abnormal regurgitation is described for valves in the aortic, mitral and right-sided positions and when to use echocardiography in suspected infective endocarditis. The roles of transoesophageal and stress echocardiography are described and finally when other imaging techniques may be useful. © 2016 The authors.

  18. 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.

  19. Understanding Heart Valve Problems and Causes

    Science.gov (United States)

    ... Check Recipe Certification Program Nutrition Requirements Heart-Check Professional Resources Contact the Heart-Check Certification Program Simple Cooking and Recipes Dining Out Choosing a Restaurant Deciphering ...

  20. [Hydrodynamics of disk artificial heart valves with different design characteristics].

    Science.gov (United States)

    Dobrova, N B; Zaretskiĭ, Iu V

    1989-01-01

    Bench tests for 38 models of artificial heart valves (AHV) with different design parameters allowed us to decide in favour of the valves with reduced eccentricity (compared to the serial AHV of the EMAHV type) according to its resistance in the constant flow. Out of the compatibility checks of the design parameters tested it was concluded that the disk did not make the complete calculated angle when rotated. The dependence of AHV resistance on the disk rotation angle showed that there is no necessity to increase that angle more than 70 degrees for the mitral valve and more than 75 degrees for the aortic AHV.

  1. 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.

  2. 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.

  3. 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.

  4. Autologous human tissue-engineered heart valves: prospects for systemic application.

    Science.gov (United States)

    Mol, Anita; Rutten, Marcel C M; Driessen, Niels J B; Bouten, Carlijn V C; Zünd, Gregor; Baaijens, Frank P T; Hoerstrup, Simon P

    2006-07-04

    Tissue engineering represents a promising approach for the development of living heart valve replacements. In vivo animal studies of tissue-engineered autologous heart valves have focused on pulmonary valve replacements, leaving the challenge to tissue engineer heart valves suitable for systemic application using human cells. Tissue-engineered human heart valves were analyzed up to 4 weeks and conditioning using bioreactors was compared with static culturing. Tissue formation and mechanical properties increased with time and when using conditioning. Organization of the tissue, in terms of anisotropic properties, increased when conditioning was dynamic in nature. Exposure of the valves to physiological aortic valve flow demonstrated proper opening motion. Closure dynamics were suboptimal, most likely caused by the lower degree of anisotropy when compared with native aortic valve leaflets. This study presents autologous tissue-engineered heart valves based on human saphenous vein cells and a rapid degrading synthetic scaffold. Tissue properties and mechanical behavior might allow for use as living aortic valve replacements.

  5. 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 patient......' perception of recovery after heart valve replacement is essential. The objective was to describe the experience of recovery at home after heart valve replacement....

  6. 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...

  7. Investigation of the fibrotic effect of the dopamine agonist "Cabergoline" on the porcine heart valve

    OpenAIRE

    Kekewska, Alexandra

    2013-01-01

    The aim of this study was to examine the side effect mechanisms of cabergoline and other ergoline compounds that cause fibrotic changes in heart valves. Heart valve fibrosis occurs during treatment of Parkinson’s disease and may cause regurgitation and even heart failure. To this date, surgical replacement with artificial valves is the only long term treatment option for patients with diseased heart valves. These pathological changes were observed in association with other influences on the s...

  8. [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.

  9. Volumetric velocimetry downstream of a percutaneous heart valve

    Science.gov (United States)

    Raghav, Vrishank; Clifford, Christopher; Midha, Prem; Okafor, Ikechukwu; Thurow, Brian; Yoganathan, Ajit; Auburn University Collaboration; Georgia Institute of Technology Collaboration

    2017-11-01

    Transcatheter aortic valve replacement has emerged as a safe and effective treatment for severe, symptomatic aortic stenosis in intermediate or greater surgical risk patients. However, despite excellent short-term outcomes, improved imaging and awareness has led to the identification of leaflet thrombosis on the aortic side of the prosthesis. Upon implantation, the transcatheter heart valve (THV) becomes enclosed in the native aortic valve leaflet tissue dividing the native sinus into two regions - a smaller anatomical sinus and a neo-sinus. To understand the causes for thrombosis, plenoptic Particle Image Velocimetry (PIV) is used to investigate the pulsatile three-dimensional flow in the sinus and neo-sinus region of the THV. Experiments are conducted on both a real and a transparent THV model in a pulsatile flow loop capable of replicating physiological hemodynamics. Comparisons with planar PIV results demonstrate the feasibility of using Plenoptic PIV to study heart valve fluid dynamics. Large three-dimensional regions of low velocity magnitude and low viscous shear stress were observed near the heart valve which could increase particle residence time potentially leading to formation of clots the THV leaflet.

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

    Science.gov (United States)

    Adlparvar, Payam; Guo, George; Kingsbury, Chris

    1993-01-01

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  12. Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

    NARCIS (Netherlands)

    Habets, Jesse; Budde, Ricardo P.; Symersky, Petr; van den Brink, Renee B.; de Mol, Bas A.; Mali, Willem P.; van Herwerden, Lex A.; Chamuleau, Steven A.

    Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these

  13. Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

    NARCIS (Netherlands)

    Habets, Jesse; Budde, Ricardo P.; Symersky, Petr; van den Brink, Renee B.; de Mol, Bas A.; Mali, Willem P.; van Herwerden, Lex A.; Chamuleau, Steven A.

    2011-01-01

    Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these

  14. Cytotoxicity of PVPAC-treated bovine pericardium: a potential replacement for glutaraldehyde in biological heart valves.

    Science.gov (United States)

    Barros, Janaina Aline Galvão; Filippin-Monteiro, Fabiola Branco; de Oliveira, Edson Mendes; Campa, Ana; Catalani, Luiz Henrique; Pitombo, Ronaldo de Nogueira Moraes; Polakiewicz, Bronislaw

    2014-04-01

    Acellular biological tissues, including bovine pericardium (BP), have been proposed as biomaterial for tissue engineering. BP is usually modified chemically to improve mechanical and biological properties using glutaraldehyde, the standard reagent for preservation of fresh bioprosthetic materials. Glutaraldehyde-fixed BP (Glut-BP), the most widely used material in heart valve manufacture, has been associated with calcification in vivo. In an attempt to reduce this issue and maintain its biocompatibility, this study assesses the physical properties and cytotoxicity of lyophilized BP treated with poly (vinylpyrrolidone-co-acrolein) (PVPAC-BP), a novel copolymer, as a substitute for glutaraldehyde. For that, PVPAC-BP surface ultrastructure, elastic function, water uptake and tissue calcification were evaluated. For the analysis of biocompatibility, fibroblasts (3T3-L1) and endothelial cells (HUVEC) were cultured on PVPAC-BP, Untreated-BP and Glut-BP. Nitric oxide (NO) release assay, fluorescence and SEM images of endothelial cells adhered on scaffolds were also performed. As results, the data show some advantages of PVPAC-BP over the Glut-BP. The PVPAC-BP maintains partially the original ultrastructure and elastic properties, improves scaffold hydration, and presents less calcium phosphate deposits. The cells demonstrated strong attachment, high proliferation rate, and formation of a monolayer on PVPAC-BP. Attached cells were also able to release NO de-monstrating regular metabolism. In conclusion, PVPAC may be considered as a promising alternative to BP treatment improving the efficiency of cell attachment and proliferation and also avoid immunogenicity. Copyright © 2013 Wiley Periodicals, Inc.

  15. 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

  16. 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

  17. First pass radionuclide studies in evaluation of left and right ventricular function in patients with bioprosthetic mitral valve replacement after 9-11 years

    International Nuclear Information System (INIS)

    Reichart, B.; Schad, N.; Hatz, R.; Bougioukas, G.; Gallucci, V.; Bortolotti, U.; Milano, A.

    1985-01-01

    The results presented here show that first pass scintigraphy is an effective diagnostic tool in evaluating tissue valves at long term risk. At 123.8 +-8 months postoperatively, 13 out of 15 patients with porcine valves in the mitral position showed normal PTT, RFR and clinical function. Two patients with bioprostheses proven to be stenotic had abnormal PTT and RFR. Valve replacement was required in these patients. In 14 patients, left and right ESV and EDV were normal at rest. Left and right ventricular responses to exercise were abnormal since ESV and EDV did not change, possibly due to decreased ventricular compliance

  18. 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...... readmission. Patients who participated in exercise-based cardiac rehabilitation (n=297) were more likely than the non-participants (n=200) to have a moderate or high physical activity level than a low physical activity level (fully adjusted OR: 1.52, 95% CI 1.03 to 2.24). CONCLUSIONS: Moderate to high levels...... of physical activity after heart valve surgery are positively associated with higher survival rates and participation in cardiac rehabilitation....

  19. Retroca valvular Replacement of heart valves prostheses

    Directory of Open Access Journals (Sweden)

    Pablo M. A Pomerantzeff

    1987-12-01

    Full Text Available A reoperação de próteses valvulares tem sido realizada, com freqüência cada vez maior, nos vários Serviços de cirurgia cardíaca. Os detalhes do tratamento, a indicação e a técnica operatória melhoraram os resultados. No período de janeiro de 1984 a junho de 1986, no Instituto do Coração, foram submetidos a retroca valvular 145 pacientes, num total de 157 próteses, e 4 trocas da bola de válvula de Starr-Edwards. Em posição mitral, 6 pacientes foram submetidos a terceira troca valvular, sem óbito imediato. A insuficiência valvular e a calcificação do tecido biológico de dura-máter foram as principais causas de indicação da reoperação. Quarenta e um pacientes apresentavam roturas e 19 pacientes, calcificação de bioprótese em posição mitral; em posição aórtica, 32 pacientes tinham rotura e 12, calcificação de bioprótese. Quanto à prótese implantada, foram utilizadas principalmente as biopróteses, sendo 63 porcinas e 35 de pericárdio bovino. A mortalidade imediata global foi de 8,3% (12 pacientes, sendo a principal causa de óbito o baixo débito cardíaco. As principais complicações imediats foram: baixo débito cardíaco, arritmias e sangramento. Noventa por cento dos pacientes encontravam-se em classe funcional (NYHA III e IV no pré-operatório, evoluindo para as classes funcionais I e II em 89% das trocas aórticas de 82% das trocas mitrais. A curva atuarial de sobrevida.em 5 semestres, foi, para a posição mitral, de 85,7% e, para a aórtica, de 91,3%. Os autores concluem que os cuidados de técnica, a proteção miocárdica e o tipo de prótese utilizada foram os responsáveis pelos resultados bastante satisfatórios.Replacement of valvular prosthesis is an increasingly frequent procedure in heart surgery. Better results are attained with the observation of correct indication and improved surgical technique. In the period of January 1984 to June 1986, 145 patients were submitted to prosthesis

  20. Sutureless aortic valve replacement using a novel autologous tissue heart valve with stent (stent biovalve): proof of concept.

    Science.gov (United States)

    Kishimoto, Satoru; Takewa, Yoshiaki; Nakayama, Yasuhide; Date, Kazuma; Sumikura, Hirohito; Moriwaki, Takeshi; Nishimura, Motonobu; Tatsumi, Eisuke

    2015-06-01

    We developed an autologous, trileaflet tissue valve ("biovalve") using in-body tissue architecture technology to overcome the disadvantages of current bioprosthetic valves. We designed a novel biovalve with a balloon-expandable stent: the stent biovalve (SBV). This study evaluated the technical feasibility of sutureless aortic valve replacement using the SBV in an orthotopic position, as well as the functionality of the SBV under systemic circulation, in an acute experimental goat model. Three adult goats (54.5-56.1 kg) underwent sutureless AVR under cardiopulmonary bypass (CPB). The technical feasibility and functionality of the SBVs were assessed using angiography, pressure catheterization, and two-dimensional echocardiography. The sutureless AVR was successful in all goats, and all animals could be weaned off CPB. The mean aortic cross-clamp time was 45 min. Angiogram, after weaning the animals off CPB, showed less than mild paravalvular leakage and central leakage was not detected in any of the goats. The mean peak-to-peak pressure gradient was 6.3 ± 5.0 mmHg. Epicardial two-dimensional echocardiograms showed smooth leaflet movement, including adequate closed positions with good coaptation; the open position demonstrated a large orifice area (average aortic valve area 2.4 ± 0.1 cm2). Sutureless AVR, using SBVs, was feasible in a goat model. The early valvular functionalities of the SBV were sufficient; future long-term experiments are needed to evaluate its durability and histological regeneration potential.

  1. 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.

  2. [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.

  3. 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.

  4. 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

  5. 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

  6. Emergency heart valve replacement: an analysis of 170 patients.

    Science.gov (United States)

    Louw, J W; Kinsley, R H; Dion, R A; Colsen, P R; Girdwood, R W

    1980-05-01

    The results of 170 emergency heart valve procedures performed during a 4 1/2-year period were analyzed. Five pathological groups of patients were recognized: those with infective endocarditis (Group 1, 28 patients); acute rheumatic carditis (Group 2, 43 patients); previous valve operation (Group 3, 29 patients); acute-on-chronic cardiac disease (Group 4, 67 patients); and miscellaneous conditions (Group 5, 3 patients). Mitral, aortic, and multiple valve procedures were performed on 58, 65, and 44 patients, respectively. The most common functional lesion was regurgitation. Hospital mortality was highest in Groups 3 (34%) and 4 (31%). By contrast, among the hospital survivors, the highest rate of attrition was in Group 2. Myocardial failure was the predominat cause of death. In view of the hopeless prognosis without operation, the 52% overall 3-year actuarial survival is a gratifying salvage. Unnecessary procrastination can only jeopardize the prospects for surgical cure.

  7. Antiplatelet and anticoagulation for patients with prosthetic heart valves.

    Science.gov (United States)

    Massel, David R; Little, Stephen H

    2013-07-09

    Patients with prosthetic heart valves are at increased risk for valve thrombosis and arterial thromboembolism. Oral anticoagulation alone, or the addition of antiplatelet drugs, has been used to minimise this risk. An important issue is the effectiveness and safety of the latter strategy. This is an update of our previous review; the goal was to create a valid synthesis of all available, methodologically sound data to further assess the safety and efficacy of combined oral anticoagulant and antiplatelet therapy versus oral anticoagulant monotherapy in patients with prosthetic heart valves. We updated the previous searches from 2003 and 2010 on 16 January 2013 and searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (2012, Issue 12), MEDLINE (OVID, 1946 to January Week 1 2013), and EMBASE (OVID, 1980 to 2013 Week 02). We have also looked at reference lists of individual reports, review articles, meta-analyses, and consensus statements. We included reports published in any language or in abstract form. All reports of randomised controlled trials comparing standard-dose oral anticoagulation to standard-dose oral anticoagulation and antiplatelet therapy in patients with one or more prosthetic heart valves. Two review authors independently performed the search strategy, assessed trials for inclusion and study quality, and extracted data. We collected adverse effects information from the trials. One new study has been identified and included in this update. In total, 13 studies involving 4122 participants were included in this review update. Years of publication ranged from 1971 to 2011. Compared with anticoagulation alone, the addition of an antiplatelet agent reduced the risk of thromboembolic events (odds ratio (OR) 0.43, 95% confidence interval (CI) 0.32 to 0.59; P heart valves. The risk of major bleeding is increased with antiplatelet therapy. These results apply to patients with mechanical prosthetic valves or those with

  8. Heart Valve Surgery Recovery and Follow Up

    Science.gov (United States)

    ... health are a good diet and a regular exercise routine. If your doctor has recommended a particular diet, it's important that you follow it. If a special diet has not been recommended, balanced, heart-healthy nutrition can speed healing and lessen fatigue. Weight ...

  9. Tissue engineering of heart valves using decellularized xenogeneic or polymeric starter matrices

    OpenAIRE

    Schmidt, Dörthe; Stock, Ulrich A; Hoerstrup, Simon P

    2007-01-01

    Heart valve replacement represents the most common surgical therapy for end-stage valvular heart diseases. A major drawback that all contemporary heart valve replacements have in common is the lack of growth, repair and remodelling capability. In order to overcome these limitations, the emerging new field of tissue engineering is focusing on the in vitro generation of functional, living heart valve replacements. The basic approach uses starter matrices either of decellularized xenogeneic or p...

  10. 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

  11. Minimally invasive heart valve surgery: how and why in 2012.

    Science.gov (United States)

    Suri, Rakesh M; Thalji, Nassir M

    2012-04-01

    Cardiac surgical procedures via traditional sternotomy are safe and effective operations performed by cardiothoracic surgeons worldwide. However, postoperative limitations in upper extremity activity during bone healing are seen as undesirable by some. Percutaneous catheter-based attempts to emulate the outcomes of traditional cardiac surgical procedures have largely fallen short of established standards of efficacy and durability. The field of minimally invasive heart valve surgery thus developed out of a need to offer smaller, better-tolerated incisions to patients while maintaining high-quality clinical outcomes. These operations are safe and effective when performed by proficient surgical teams, allowing patients to resume normal activities more rapidly. We explore current evidence supporting the practice of minimally invasive heart valve surgery in 2012 and analyze the clinical impact of these nascent surgical platforms.

  12. 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.

  13. 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.

  14. Beating-heart surgical treatment of tricuspid valve papillary fibroelastoma

    OpenAIRE

    Li, Weidong; Zheng, Junnan; Zhao, Hengchi; Xu, Hongfei; Ni, Yiming

    2016-01-01

    Abstract Background: Cardiac papillary fibroelastomas are rare. And only 15% of the papillary fibroelastomas are located on tricuspid valve. However, the treatment of papillary fibroelastomas varies. Case summary: We report a 75-year-old Chinese male who was hospitalized because of a right atrial mass found by echocardiography. Complete tumor excision along with Kay's tricuspid valvuloplasty surgery on beating heart under cardiopulmonary bypass was performed to the patient. Pathologic examina...

  15. Absent pulmonary valve, tricuspid atresia, and congenital heart block.

    Science.gov (United States)

    Juaneda, Ignacio; Rychik, Jack; Fuller, Stephanie; Weinberg, Paul M; Rome, Jonathan J; Mahle, William T; Gaynor, J William

    2015-01-01

    We describe management of a patient with a prenatal diagnosis of absent pulmonary valve, tricuspid atresia, ventricular septal defect, and congenital heart block. Initial treatment consisted of temporary pacemaker implantation, and subsequent palliation included a central shunt during the neonatal period and placement of a permanent pacemaker. At seven months of age, a bidirectional Glenn anastomosis was performed. Cardiac catheterization revealed high cavopulmonary pressures and ventricular dysfunction precluding Fontan completion. Heart transplantation was performed at 3.75 years of age. The patient is alive and well 26 months posttransplantation. © The Author(s) 2014.

  16. 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.

  17. Clinical results of implanted tissue engineered heart valves.

    Science.gov (United States)

    Dohmen, P M

    2012-01-01

    Since the first heterotopic implantation of a biological heart valve in 1955 by Murray, bioprostheses have been steadily improved. For allografts different methods have been evaluated and modified to stabilize and preserve the available tissue. Xenografts were fixed to cross-link the connective tissue as well as prevent immunogenic reactions. Nevertheless, gluteraldehyde fixation leads to structural deterioration, which could only be partially reduced by different kinds of anti-mineralization treatment. Due to preservation and fixation, allografts and xenografts become non-viable bioprostheses with a lack of remodelling, regeneration and growth. Tissue engineering is a possible key to overcome these disadvantages as it will provide living tissue with remodelling, regeneration and growth potential. This overview will look at the key points to provide such tissue engineered heart valves by creating an appropriate scaffold where cells can grow, either in vitro or in vivo and remodel a neo-scaffold which will lead to a functional autologous heart valve, and show initial clinical results.

  18. 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 Copenhagen, Frederiksberg, Denmark. 2. Novo Nordic A/S, Maaloev, Denmark. 3. Department of Clinical Sciences, Swedish University of Agricultural Science, Uppsala, Sweden. Heart rate variability (HRV) is an indirect measurement of the autonomic modulation of heart rate (HR). Reduced HRV measured from short......-time electrocardiography is seen in dogs with heart failure (HF) secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease severity at early stages of MMVD. The aims of this study were 1) to associate HR and HRV with severity of MMVD in Cavalier King Charles Spaniels (CKCS...

  19. 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

  20. Coronary artery assessment by multidetector computed tomography in patients with prosthetic heart valves

    International Nuclear Information System (INIS)

    Habets, Jesse; Mali, Willem P.T.M.; Budde, Ricardo P.J.; Brink, Renee B.A. van den; Uijlings, Ruben; Spijkerboer, Anje M.; Chamuleau, Steven A.J.

    2012-01-01

    Patients with prosthetic heart valves may require assessment for coronary artery disease. We assessed whether valve artefacts hamper coronary artery assessment by multidetector CT. ECG-gated or -triggered CT angiograms were selected from our PACS archive based on the presence of prosthetic heart valves. The best systolic and diastolic axial reconstructions were selected for coronary assessment. Each present coronary segment was scored for the presence of valve-related artefacts prohibiting coronary artery assessment. Scoring was performed in consensus by two observers. Eighty-two CT angiograms were performed on a 64-slice (n = 27) or 256-slice (n = 55) multidetector CT. Eighty-nine valves and five annuloplasty rings were present. Forty-three out of 1160 (3.7%) present coronary artery segments were non-diagnostic due to valve artefacts (14/82 patients). Valve artefacts were located in right coronary artery (15/43; 35%), left anterior descending artery (2/43; 5%), circumflex artery (14/43; 32%) and marginal obtuse (12/43; 28%) segments. All cobalt-chrome containing valves caused artefacts prohibiting coronary assessment. Biological and titanium-containing valves did not cause artefacts except for three specific valve types. Most commonly implanted prosthetic heart valves do not hamper coronary assessment on multidetector CT. Cobalt-chrome containing prosthetic heart valves preclude complete coronary artery assessment because of severe valve artefacts. circle Most commonly implanted prosthetic heart valves do not hamper coronary artery assessment circle Prosthetic heart valve composition determines the occurrence of prosthetic heart valve-related artefacts circle Bjoerk-Shiley and Sorin tilting disc valves preclude diagnostic coronary artery segment assessment. (orig.)

  1. Coronary artery assessment by multidetector computed tomography in patients with prosthetic heart valves.

    Science.gov (United States)

    Habets, Jesse; van den Brink, Renee B A; Uijlings, Ruben; Spijkerboer, Anje M; Mali, Willem P Th M; Chamuleau, Steven A J; Budde, Ricardo P J

    2012-06-01

    Patients with prosthetic heart valves may require assessment for coronary artery disease. We assessed whether valve artefacts hamper coronary artery assessment by multidetector CT. ECG-gated or -triggered CT angiograms were selected from our PACS archive based on the presence of prosthetic heart valves. The best systolic and diastolic axial reconstructions were selected for coronary assessment. Each present coronary segment was scored for the presence of valve-related artefacts prohibiting coronary artery assessment. Scoring was performed in consensus by two observers. Eighty-two CT angiograms were performed on a 64-slice (n = 27) or 256-slice (n = 55) multidetector CT. Eighty-nine valves and five annuloplasty rings were present. Forty-three out of 1160 (3.7%) present coronary artery segments were non-diagnostic due to valve artefacts (14/82 patients). Valve artefacts were located in right coronary artery (15/43; 35%), left anterior descending artery (2/43; 5%), circumflex artery (14/43; 32%) and marginal obtuse (12/43; 28%) segments. All cobalt-chrome containing valves caused artefacts prohibiting coronary assessment. Biological and titanium-containing valves did not cause artefacts except for three specific valve types. Most commonly implanted prosthetic heart valves do not hamper coronary assessment on multidetector CT. Cobalt-chrome containing prosthetic heart valves preclude complete coronary artery assessment because of severe valve artefacts. • Most commonly implanted prosthetic heart valves do not hamper coronary artery assessment • Prosthetic heart valve composition determines the occurrence of prosthetic heart valve-related artefacts • Björk-Shiley and Sorin tilting disc valves preclude diagnostic coronary artery segment assessment.

  2. 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.

  3. Coronary artery assessment by multidetector computed tomography in patients with prosthetic heart valves

    OpenAIRE

    Habets, Jesse; van den Brink, Renee B. A.; Uijlings, Ruben; Spijkerboer, Anje M.; Mali, Willem P. Th. M.; Chamuleau, Steven A. J.; Budde, Ricardo P. J.

    2011-01-01

    Objectives Patients with prosthetic heart valves may require assessment for coronary artery disease. We assessed whether valve artefacts hamper coronary artery assessment by multidetector CT. Methods ECG-gated or -triggered CT angiograms were selected from our PACS archive based on the presence of prosthetic heart valves. The best systolic and diastolic axial reconstructions were selected for coronary assessment. Each present coronary segment was scored for the presence of valve-related artef...

  4. 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.

  5. 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.

  6. 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

  7. 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

    2011-10-01

    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. 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.

  8. Controlled cyclic stretch bioreactor for tissue-engineered heart valves.

    Science.gov (United States)

    Syedain, Zeeshan H; Tranquillo, Robert T

    2009-09-01

    A tissue-engineered heart valve (TEHV) represents the ultimate valve replacement, especially for juvenile patients given its growth potential. To date, most TEHV bioreactors have been developed based on pulsed flow of culture medium through the valve lumen to induce strain in the leaflets. Using a strategy for controlled cyclic stretching of tubular constructs reported previously, we developed a controlled cyclic stretch bioreactor for TEHVs that leads to improved tensile and compositional properties. The TEHV is mounted inside a latex tube, which is then cyclically pressurized with culture medium. The root and leaflets stretch commensurately with the latex, the stretching being dictated by the stiffer latex and thus controllable. Medium is also perfused through the lumen at a slow rate in a flow loop to provide nutrient delivery. Fibrin-based TEHVs prepared with human dermal fibroblasts were subjected to three weeks of cyclic stretching with incrementally increasing strain amplitude. The TEHV possessed the tensile stiffness and stiffness anisotropy of leaflets from sheep pulmonary valves and could withstand cyclic pulmonary pressures with similar distension as for a sheep pulmonary artery.

  9. Transcatheter Tricuspid Valve-in-Valve Replacement with an Edwards Sapien 3 Valve

    Science.gov (United States)

    Loyalka, Pranav; Nascimbene, Angelo; Metz, Benjamin; Gregoric, Igor D.; Raman, Ajay Sundara

    2017-01-01

    A few case reports and case series have documented the outcomes in patients with tricuspid bioprosthetic valvular degeneration who underwent transcatheter implantation of the Medtronic Melody and the Edwards Sapien XT and Sapien 3 valves. In this report, we describe the case of a 49-year-old woman with severe bioprosthetic tricuspid valvular stenosis and multiple comorbidities who underwent transcatheter tricuspid valve replacement with a Sapien 3 valve. PMID:28761403

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

    OpenAIRE

    Sibilitz, Kirstine L; Berg, Selina K; Tang, Lars H; Risom, Signe S; Gluud, Christian; Lindschou, Jane; Kober, Lars; Hassager, Christian; Taylor, Rod S; Zwisler, Ann-Dorthe

    2016-01-01

    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-based cardiac rehabilitation compared with no exercise training intervention, or treatment as usual, in adults following heart valve surgery. We considered programmes including exercise training with or witho...

  11. Anticoagulation in pregnant females with mechanical heart valves

    International Nuclear Information System (INIS)

    Shafique, H.; Chaudhry, A.; Ayyub, M.

    2006-01-01

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

  12. Adverse effects of benfluorex on heart valves and pulmonary circulation.

    Science.gov (United States)

    Szymanski, Catherine; Andréjak, Michel; Peltier, Marcel; Maréchaux, Sylvestre; Tribouilloy, Christophe

    2014-07-01

    Benfluorex is responsible for the development of restrictive valvular regurgitation due to one of its metabolites, norfenfluramine. The 5-HT2B receptor, expressed on heart valves, acts as culprit receptor for drug-induced valvular heart disease (VHD). Stimulation of this receptor leads to the upregulation of target genes involved in the proliferation and stimulation of valvular interstitial cells through different intracellular pathways. Valve lesions essentially involve the mitral and/or aortic valves. The randomised prospective REGULATE trial shows a threefold increase in the incidence of valvular regurgitation in patients exposed to benfluorex. A cross-sectional trial shows that about 7% of patients without a history of VHD previously exposed to benfluorex present echocardiographic features of drug-induced VHD. The excess risks of hospitalisation for cardiac valvular insufficiency and of valvular replacement surgery were respectively estimated to 0.5 per 1000 and 0.2 per 1000 exposed patients per year. Recent data strongly suggest an aetiological link between benfluorex exposure and pulmonary arterial hypertension (PAH). The PAH development may be explained by serotonin, which creates a pulmonary vasoconstriction through potassium-channel blockade. Further studies should be conducted to determine the subsequent course of benfluorex-induced VHD and PAH, and to identify genetic, biological and clinical factors that determine individual susceptibility to developing such adverse effects. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Prosthetic heart valve assessment with multidetector-row CT: imaging characteristics of 91 valves in 83 patients

    NARCIS (Netherlands)

    Habets, Jesse; Symersky, Petr; van Herwerden, Lex A.; de Mol, Bas A. J. M.; Spijkerboer, Anje M.; Mali, Willem P. Th M.; Budde, Ricardo P. J.

    2011-01-01

    Multidetector CT (MDCT) has shown potential for prosthetic heart valve (PHV) assessment. We assessed the image quality of different PHV types to determine which valves are suitable for MDCT evaluation. All ECG-gated CTs performed in our institutions since 2003 were reviewed for the presence of PHVs.

  14. Surgical pathology of excised heart valves in a referral hospital in iran

    International Nuclear Information System (INIS)

    Yaghoubi, A.R.; Raeesi, K.

    2007-01-01

    Assessment of surgical pathology of excised heart valves in a referral hospital in Iran in a five years period. This retrospective descriptive study was done from 2002 to 2005 in Rajaie heart center in Tehran, Iran. Surgery and pathology records of patients who underwent valve replacement or repair surgery were reviewed. Of 1563 patients 738 (47.2%) underwent mitral, 565 (36.1%) aortic, and 215 (14%) multivalve operation. Most common pathology of mitral valve was rheumatic (68%), while degenerative calcific pathology was dominant in aortic valve (52%). Rheumatic involvement was 46%, and degenerative pathology was common in tricuspid and pulmonary valves (50% and 67%, respectively). Time trend analysis shows no significant variation in excised valves pathology or pattern from 2002 to 2005 (p=0.112). Rheumatic pathology in excised heart valves is still common in this referral heart center in Iran, and no obvious change in this pattern was found during a 5 years period. (author)

  15. 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.

  16. Design of a miniature tissue culture system to culture mouse heart valves.

    Science.gov (United States)

    Lieber, Samuel C; Kruithof, Boudewijn P T; Aubry, Nadine; Vatner, Stephen F; Gaussin, Vinciane

    2010-03-01

    Valvular heart disease is a leading cause of morbidity and mortality in adults but little is known about the underlying etiology. A better understanding of the genetic and hemodynamic mechanisms involved in growth and remodeling of heart valves during physiological and pathological conditions is needed for a better understanding of valvular heart disease. Here, we report the design of a miniature tissue culture system (MTCS) that allows the culture of mitral valves from perinatal to adult mice. The design of the MTCS is novel in that fine positioning and cannulation can be conducted with hearts of different sizes (perinatal to adult). Perfusion of the heart and hence, culture of the mitral valve in its natural position, occurs in a hydraulically sealed culture bath environment. Using the MTCS, we successfully cultured the mitral valve of adult mouse hearts for 3 days. Histological analysis indicated that the cultured valves remained viable and their extracellular matrix organization was similar to age-matched native valves. Gene expression could also be modified in cultured valves by perfusion with medium containing beta-galactosidase-expressing adenovirus. Thus, the MTCS is a new tool to study the genetic and hemodynamic mechanisms underlying the three-dimensional organization of the heart valves, which could provide insights in the pathology of valvular heart disease and be used in animal models for the development of tissue-engineered heart valves.

  17. Effects of valve geometry and tissue anisotropy on the radial stretch and coaptation area of tissue-engineered heart valves.

    Science.gov (United States)

    Loerakker, S; Argento, G; Oomens, C W J; Baaijens, F P T

    2013-07-26

    Tissue engineering represents a promising technique to overcome the limitations of the current valve replacements, since it allows for creating living autologous heart valves that have the potential to grow and remodel. However, also this approach still faces a number of challenges. One particular problem is regurgitation, caused by cell-mediated tissue retraction or the mismatch in geometrical and material properties between tissue-engineered heart valves (TEHVs) and their native counterparts. The goal of the present study was to assess the influence of valve geometry and tissue anisotropy on the deformation profile and closed configuration of TEHVs. To achieve this aim, a range of finite element models incorporating different valve shapes was developed, and the constitutive behavior of the tissue was modeled using an established computational framework, where the degree of anisotropy was varied between values representative of TEHVs and native valves. The results of this study suggest that valve geometry and tissue anisotropy are both important to maximize the radial strains and thereby the coaptation area. Additionally, the minimum degree of anisotropy that is required to obtain positive radial strains was shown to depend on the valve shape and the pressure to which the valves are exposed. Exposure to pulmonary diastolic pressure only yielded positive radial strains if the anisotropy was comparable to the native situation, whereas considerably less anisotropy was required if the valves were exposed to aortic diastolic pressure. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. A new approach to heart valve tissue engineering

    DEFF Research Database (Denmark)

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

    2011-01-01

    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...... 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......, variable throttle and reservoir, connected by silicone tubings. The reservoir sat on an elevated platform, allowing adjustment of ventricular preload between 0 and 11 mmHg. To allow for sterile gaseous exchange between the circuit interior and exterior, a 0.2 µm filter was placed at the reservoir. Pressure...

  19. Current developments in the tissue engineering of autologous heart valves: moving towards clinical use.

    Science.gov (United States)

    Apte, Sameer S; Paul, Arghya; Prakash, Satya; Shum-Tim, Dominique

    2011-01-01

    The use of tissue-engineering methods to create autologous heart valve constructs has the potential to overcome the fundamental drawbacks of more traditional valve prostheses. Traditional mechanical valves, while durable, increase the risk for endocarditis and thrombogenesis, and require the recipient to continue lifelong anticoagulant therapy. Homograft or xenograft heart valve prostheses are associated with immune reaction and progressive deterioration with limited durability. Most importantly, neither option is capable of growth and remodeling in vivo and both options place the patient at risk for valve-related complications and reoperation. These shortcomings have prompted the application of tissue-engineering techniques to create fully autologous heart valve replacements. Future clinically efficacious tissue-engineered autologous valves should be nonthrombogenic, biocompatible, capable of growth and remodeling in vivo, implantable with current surgical techniques, hemodynamically perfect, durable for the patient's life and most importantly, significantly improve quality of life for the patient. In order to meet these expectations, the nature of the ideal biochemical milieu for conditioning an autologous heart valve will need to be elucidated. In addition, standardized criteria by which to quantitatively evaluate a tissue-engineered heart valve, as well as noninvasive analytical techniques for use in long-term animal models, will be required. This article highlights the advances, challenges and future clinical prospects in the field of tissue engineering of autologous heart valves, focusing on progress made by studies that have investigated a fully autologous, tissue-engineered pulmonary valve replacement in vivo.

  20. [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.

  1. Aortic Valve Regurgitation

    Science.gov (United States)

    ... correct direction. These valves include the mitral valve, tricuspid valve, pulmonary valve and aortic valve. Each valve has ... Causes of aortic valve regurgitation include: Congenital heart valve disease. You may have been born with an aortic ...

  2. 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.

  3. UDP-glucose Dehydrogenase Polymorphisms from Patients with Congenital Heart Valve Defects Disrupt Enzyme Stability and Quaternary Assembly

    NARCIS (Netherlands)

    Hyde, Annastasia S.; Farmer, Erin L.; Easley, Katherine E.; van Lammeren, Kristy; Christoffels, Vincent M.; Barycki, Joseph J.; Bakkers, Jeroen; Simpson, Melanie A.

    2012-01-01

    Cardiac valve defects are a common congenital heart malformation and a significant clinical problem. Defining molecular factors in cardiac valve development has facilitated identification of underlying causes of valve malformation. Gene disruption in zebrafish revealed a critical role for

  4. UDP-glucose dehydrogenase polymorphisms from patients with congenital heart valve defects disrupt enzyme stability and quaternary assembly

    NARCIS (Netherlands)

    Hyde, A.S.; Farmer, E.L.; Easley, K.E.; van Lammeren, K.; Christoffels, V.M.; Barycki, J.J.; Bakkers, J.; Simpson, M.A.

    2012-01-01

    Cardiac valve defects are a common congenital heart malformation and a significant clinical problem. Defining molecular factors in cardiac valve development has facilitated identification of underlying causes of valve malformation. Gene disruption in zebrafish revealed a critical role for

  5. Early outcomes of percutaneous pulmonary valve implantation using the Edwards SAPIEN XT transcatheter heart valve system.

    Science.gov (United States)

    Haas, Nikolaus A; Carere, Ronald Giacomo; Kretschmar, Oliver; Horlick, Eric; Rodés-Cabau, Josep; de Wolf, Daniël; Gewillig, Marc; Mullen, Michael; Lehner, Anja; Deutsch, Cornelia; Bramlage, Peter; Ewert, Peter

    2018-01-01

    Patients with congenital or acquired heart defects affecting the pulmonary valve and right ventricular outflow tract (RVOT) commonly require multiple surgical interventions, resulting in significant morbidity. A less invasive alternative is percutaneous pulmonary valve implantation (PPVI). Though studies have previously reported the safety and efficacy of the early generation transcatheter heart valves (THVs), data on more recent devices are severely lacking. We performed a multinational, multicentre, retrospective, observational registry analysis of patients who underwent PPVI using the Edwards SAPIEN XT THV. Of the 46 patients that were enrolled, the majority had tetralogy of Fallot as the underlying diagnosis (58.7%), and stentless xenograft as the most common RVOT anatomy (34.8%). Procedural success rate was high (93.5%), with a low frequency of periprocedural complications and adverse events (6.5% and 10.9%, respectively). At 30days post-procedure, NYHA class had improved significantly (90.6% were at NYHA I or II). The rate of moderate/severe pulmonary regurgitation had decreased from 76.1% at baseline to 5.0% at 30days, and the calculated peak systolic gradient had decreased from 45.2 (SD±21.3) mmHg to 16.4 (SD±8.0) mmHg, with these values remaining low up to 2years. The data suggest the efficacy and safety of the SAPIEN XT THV in PPVI in common anatomies in patients with conduits, as well as those with native pulmonary valves or transannular patches. Continued data collection is necessary to verify long-term findings. CLINICALTRIALS. NCT02302131. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. [Functional characteristics of flexible supporting structures for heart valve bioprosthesis].

    Science.gov (United States)

    Dobrova, N B; Agafonov, A V; Barbarash, L S; Zavalishin, N N; Neniukov, A K

    1984-01-01

    Hydraulic characteristics of heart valve bioprostheses mounted on supporting structures of various rigidity have been studied under physiologic conditions. An actual mobility of the supporting structures made of different polymers is determined. Static and dynamic components of the support displacements have been shown to develop as the bioprosthesis is under the load, the dynamic component being strongly dependent upon the rigidity of fastening the bioprosthesis on the axis. It is noted that considerable improvements in hydraulic characteristics of bioprostheses are achieved through the use of flexible supporting structures.

  7. 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

  8. Hyaluronan Hydrogels for a Biomimetic Spongiosa Layer of Tissue Engineered Heart Valve Scaffolds.

    Science.gov (United States)

    Puperi, Daniel S; O'Connell, Ronan W; Punske, Zoe E; Wu, Yan; West, Jennifer L; Grande-Allen, K Jane

    2016-05-09

    Advanced tissue engineered heart valves must be constructed from multiple materials to better mimic the heterogeneity found in the native valve. The trilayered structure of aortic valves provides the ability to open and close consistently over a full human lifetime, with each layer performing specific mechanical functions. The middle spongiosa layer consists primarily of proteoglycans and glycosaminoglycans, providing lubrication and dampening functions as the valve leaflet flexes open and closed. In this study, hyaluronan hydrogels were tuned to perform the mechanical functions of the spongiosa layer, provide a biomimetic scaffold in which valve cells were encapsulated in 3D for tissue engineering applications, and gain insight into how valve cells maintain hyaluronan homeostasis within heart valves. Expression of the HAS1 isoform of hyaluronan synthase was significantly higher in hyaluronan hydrogels compared to blank-slate poly(ethylene glycol) diacrylate (PEGDA) hydrogels. Hyaluronidase and matrix metalloproteinase enzyme activity was similar between hyaluronan and PEGDA hydrogels, even though these scaffold materials were each specifically susceptible to degradation by different enzyme types. KIAA1199 was expressed by valve cells and may play a role in the regulation of hyaluronan in heart valves. Cross-linked hyaluronan hydrogels maintained healthy phenotype of valve cells in 3D culture and were tuned to approximate the mechanical properties of the valve spongiosa layer. Therefore, hyaluronan can be used as an appropriate material for the spongiosa layer of a proposed laminate tissue engineered heart valve scaffold.

  9. 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.

  10. PIV validation of blood-heart valve leaflet interaction modelling.

    Science.gov (United States)

    Kaminsky, R; Dumont, K; Weber, H; Schroll, M; Verdonck, P

    2007-07-01

    The aim of this study was to validate the 2D computational fluid dynamics (CFD) results of a moving heart valve based on a fluid-structure interaction (FSI) algorithm with experimental measurements. Firstly, a pulsatile laminar flow through a monoleaflet valve model with a stiff leaflet was visualized by means of Particle Image Velocimetry (PIV). The inflow data sets were applied to a CFD simulation including blood-leaflet interaction. The measurement section with a fixed leaflet was enclosed into a standard mock loop in series with a Harvard Apparatus Pulsatile Blood Pump, a compliance chamber and a reservoir. Standard 2D PIV measurements were made at a frequency of 60 bpm. Average velocity magnitude results of 36 phase-locked measurements were evaluated at every 10 degrees of the pump cycle. For the CFD flow simulation, a commercially available package from Fluent Inc. was used in combination with inhouse developed FSI code based on the Arbitrary Lagrangian-Eulerian (ALE) method. Then the CFD code was applied to the leaflet to quantify the shear stress on it. Generally, the CFD results are in agreement with the PIV evaluated data in major flow regions, thereby validating the FSI simulation of a monoleaflet valve with a flexible leaflet. The applicability of the new CFD code for quantifying the shear stress on a flexible leaflet is thus demonstrated.

  11. In-vivo blood velocity and velocity gradient profiles downstream of stented and stentless aortic heart valves.

    Science.gov (United States)

    Funder, Jonas A; Frost, Markus W; Ringgaard, Steffen; Klaaborg, Kaj-Erik; Wierup, Per; Hjortdal, Vibeke; Nygaard, Hans; Hasenkam, J Michael

    2010-05-01

    Abnormal flow conditions across aortic bioprosthetic valves may result in degenerative processes. Thus, it is important to implant biological valve prostheses with velocity profiles similar to those of native valves. The study aim was to compare blood velocity and velocity gradient profiles downstream of stented and stentless aortic valves implanted in pigs, and in native porcine valves. Stented valve prostheses (Mitroflow, n = 7) or stentless valve prostheses (Solo, n = 5 or Toronto SPV, n = 7) were implanted into pigs; the native valve was retained in eight animals. After weaning the animals from cardiopulmonary bypass, cardiac magnetic resonance imaging was performed to determine the blood velocities and velocity gradient profiles. The native valves had a significantly lower peak velocity (92 +/- 26 cm/s) than the artificial valves (Solo: 247 +/- 107 cm/s; Toronto: 252 +/- 41 cm/s; Mitroflow: 229 +/- 18 cm/s). The native valves exhibited a flat velocity profile during systole, whereas the Solo valve, and especially the Toronto SPV valve, displayed more parabola-shaped velocity profiles; velocity profiles downstream of the Mitroflow valve exhibited a flat shape. The native valves had a lower mean velocity gradient at peak systole (p valve (0.14 +/- 0.11; p valve had a percentage of 0.57 +/- 0.09, which was lower than the Solo valve (0.69 +/- 0.12; p = 0.074), and significantly lower than the Toronto valve (0.70 +/- 0.08; p = 0.015). All valves displayed high velocity gradients adjacent to the aortic wall; in particular, the Toronto SPV which also had high velocity gradients at the center of the vessel. All of the artificial valves tested had a significantly higher mean velocity gradient and peak velocity than the native valves. However, the Mitroflow had a mean velocity and a velocity gradient percentage lower than the two stentless valves. The Solo and Mitroflow valves displayed velocity profiles most like native valves, while the Toronto valve had a more

  12. Intense Microbubbles Mimicking Mobile Thrombus in a Patient with Prosthetic Mitral Valve

    Directory of Open Access Journals (Sweden)

    Fatma Yılmaz Coşkun

    2017-06-01

    Full Text Available Microbubbles have been presumed as gaseous emboli, which originate during mechanical heart valve closure, but are not seen in bioprosthetic valves. In this report, we presented a cluster of microbubbles mimicking mobile thrombus in a patient with mechanical mitral valve prosthesis. A 30-year-old female with a history of implanted mechanical valve at the mitral position underwent a routine examination. She was asymptomatic and her physical examination was unremarkable. Transthoracic echocardiography showed a mobile thrombus-like mass on the ventricular side of the prosthetic mitral valve moving into the left ventricular outflow tract. However, close examination of images indicated that the mass was in fact intense microbubbles mimicking thrombus. Intense mobile microbubbles can be misdiagnosed as a mobile thrombus. We recommend and underscore the importance of detailed echocardiographic examination in case of mobile mass to avoid misdiagnosis in patients with mechanical heart valves.

  13. Tangible nanocomposites with diverse properties for heart valve application

    International Nuclear Information System (INIS)

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

    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. (review)

  14. 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

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

    NARCIS (Netherlands)

    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

  16. 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

    BACKGROUND: 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 develop......BACKGROUND: 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. METHODS: 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...

  17. 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

  18. 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.

  19. Co-ordinating Notch, BMP, and TGFβ Signalling During Heart Valve Development

    Science.gov (United States)

    Garside, Victoria C.; Chang, Alex C.; Karsan, Aly; Hoodless, Pamela A.

    2015-01-01

    Congenital heart defects affect approximately 1–5% of human newborns each year and of these cardiac defects, 20–30% are due to heart valve abnormalities. Recent literature indicates that key factors and pathways that regulate valve development are also implicated in congenital heart defects and valve disease. Currently, there are limited options for treatment of valve disease and therefore, having a better understanding of valve development can contribute critical insight into congenital valve defects and disease. There are three major signalling pathways required for early specification and initiation of Endothelial-to-Mesenchymal Transformation (EMT) in the cardiac cushions: BMP, TGFβ, and Notch signalling. BMPs secreted from the myocardium setup the environment for the overlying endocardium to become activated, Notch signalling initiates EMT, and both BMP and TGFβ signalling synergizes with Notch to promote the transition of endothelia to mesenchyme and to promote mesenchymal cell invasiveness. Together, these three essential signalling pathways help to form the cardiac cushions and populate them with mesenchyme and, consequently, set off the cascade of events required to develop mature heart valves. Furthermore, integration and cross-talk between these pathways generate highly stratified and delicate valve leaflets and septa of the heart. Here, we discuss BMP, TGFβ, and Notch signalling pathways during mouse cardiac cushion formation and how they together produce a coordinated EMT response in the developing mouse valves. PMID:23161060

  20. Acupuncture in patients with valvular heart disease and prosthetic valves.

    Science.gov (United States)

    Stellon, Anthony

    2003-09-01

    Endocarditis has been reported in patients with valvular heart disease who have undergone acupuncture treatment, although most have been associated with the use of semi-permanent needles. This has led reviewers to suggest that acupuncture may not only be contraindicated in such patients but that prophylactic antibiotics should be given. This study investigated the use of acupuncture treatment in patients with proven valvular heart disease and observed whether endocarditis developed in such patients. All patients in a single-handed GP practice with proven valvular heart disease, including those with prosthetic valves, were identified over a ten-year period. Those who had undergone acupuncture treatment underwent a clinical examination and diagnostic tests, which focused on the signs, symptoms and laboratory criteria for the diagnosis of endocarditis and included a transthoracic echocardiogram. Autopsy findings were reviewed in any patient who died. Based on these clinical and laboratory data, using the modified Duke's criteria for the diagnosis of endocarditis, patients were identified as having definite or possible endocarditis, or the diagnosis was rejected. All patients underwent brief acupuncture with no skin disinfectant and no prophylactic antibiotics were given. Semi-permanent needles were avoided. Thirty-six patients with valvular heart disease underwent a total of 479 acupuncture treatments over a ten-year period. The median number of treatments was 9 (range 1-72), with a follow-up after treatment of 5.75 years (range 0.5-10 years). Definite endocarditis was not found in any patient, but two patients had possible endocarditis, eventually discounted by both negative blood cultures and echocardiography. In conclusion, brief acupuncture was safe in this small cohort of valvular heart disease patients and no case of endocarditis was detected over a ten-year period.

  1. 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

  2. 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.

  3. 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.......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....

  4. [Myxoma Originating from the Tricuspid Annulus Requiring Annular Reconstruction and Valve Replacement;Report of a Case].

    Science.gov (United States)

    Hattori, Masashi; Matsumura, Yu; Yamaki, Fumitaka

    2016-07-01

    A 66-year-old woman who had had coughing and worsening dyspnea for 3 weeks was admitted to our hospital. Echocardiography showed a solid round mass (72×49 mm in diameter) attached to the tricuspid septal annulus with a short stalk. A right atrial myxoma was suspected and operation was performed under cardiopulmonary bypass after heart failure symptoms subsided. The tumor was extirpated along with the tricuspid valve annulus. We performed reconstruction of the tricuspid annulus, tricuspid valve replacement with a bioprosthetic valve and pacemaker implantation. The histopathologic diagnosis was myxoma. The postoperative course was uneventful, and no recurrence has been noted for 1 year after surgery.

  5. 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......, with patients in the capital region less likely to be referred (0.22 (0.08-0.57)). Patients with TAVI were less likely to participate (0.29 (0.12-0.70)). CONCLUSIONS: Despite high national programme coverage, only half the patients post heart valve surgery received CR. Both factors identified at provider......- 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....

  6. Heart valve disease: the role of calcidiol deficiency, elevated parathyroid hormone levels and oxidative stress in mitral and aortic valve insufficiency.

    Science.gov (United States)

    Eren, Esin; Ellidag, Hamit Yasar; Cekin, Yesim; Ayoglu, Raif Umut; Sekercioglu, Ali Osman; Yılmaz, Necat

    2014-01-01

    Endothelia, intima, and connective tissues comprise the heart valves, but the relationship between heart valve damage, the pathogenesis of valve degeneration, and vitamin D, oxidative stress remains unclear. Here, we assessed serum 25(OH) vitamin D (calcidiol), parathormone (PTH), and redox balance in patients with mitral valve regurgitation (MR) and aortic valve regurgitation (AR). This study includes 56 chronic heart valve disease (HVD) patients. Patients were diagnosed with MR or AR depending on the echocardiographic findings. Also, 40 sex-matched healthy control participants were enrolled for comparison. Serum calcidiol, PTH, total oxidative status (TOS), and total antioxidative capacity were measured, and the oxidative stress index (OSI) was calculated. Patients with HVD demonstrated significantly higher PTH, increased TOS and OSI, and a higher frequency of calcidiol deficiency than the control participants. Calcidiol and TOS were negatively correlated (r = -0.29; P Heart valve regurgitation (AR and MR) is correlated to oxidative stress and hypovitaminosis D.

  7. Tissue engineering of heart valves by recellularization of glutaraldehyde-fixed porcine valves using bone marrow-derived cells.

    Science.gov (United States)

    Kim, Sang Soo; Lim, Sang Hyun; Cho, Seung Woo; Gwak, So Jung; Hong, Yoo Sun; Chang, Byung Chul; Park, Moon Hyang; Song, Kang Won; Choi, Cha Yong; Kim, Byung Soo

    2006-06-30

    To increase the biocompatibility and durability of glutaraldehyde (GA)-fixed valves, a biological coating with viable endothelial cells (ECs) has been proposed. However, stable EC layers have not been formed successfully on GA-fixed valves due to their inability to repopulate. In this study, to improve cellular adhesion and proliferation, the GA-fixed prostheses were detoxified by treatment with citric acid to remove free aldehyde groups. Canine bone marrow mononuclear cells (MNCs) were differentiated into EC-like cells and myofibroblast-like cells in vitro. Detoxified prostheses were seeded and recellularized with differentiated bone marrow- derived cells (BMCs) for seven days. Untreated GA-fixed prostheses were used as controls. Cell attachment, proliferation, metabolic activity, and viability were investigated and cell-seeded leaflets were histologically analyzed. On detoxified GA-fixed prostheses, BMC seeding resulted in uninhibited cell proliferation after seven days. In contrast, on untreated GA-fixed prostheses, cell attachment was poor and no viable cells were observed. Positive staining for smooth muscle a-actin, CD31, and proliferating cell nuclear antigen was observed on the luminal side of the detoxified valve leaflets, indicating differentiation and proliferation of the seeded BMCs. These results demonstrate that the treatment of GA-fixed valves with citric acid established a surface more suitable for cellular attachment and proliferation. Engineering heart valves by seeding detoxified GA-fixed biological valve prostheses with BMCs may increase biocompatibility and durability of the prostheses. This method could be utilized as a new approach for the restoration of heart valve structure and function in the treatment of end-stage heart valve disease.

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

    Science.gov (United States)

    Simionescu, Dan T.; Chen, Joseph; Jaeggli, Michael; Wang, Bo; Liao, Jun

    2013-01-01

    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: replication of the native valve trilayered histoarchitecture, duplication of the three-dimensional shape of the valve 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. PMID:23355946

  9. 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.

  10. Comparison of the Long-Term Outcomes of Mechanical and Bioprosthetic Aortic Valves - A Propensity Score Analysis.

    Science.gov (United States)

    Minakata, Kenji; Tanaka, Shiro; Tamura, Nobushige; Yanagi, Shigeki; Ohkawa, Yohei; Okonogi, Shuichi; Kaneko, Tatsuo; Usui, Akihiko; Abe, Tomonobu; Shimamoto, Mitsuomi; Takahara, Yoshiharu; Yamanaka, Kazuo; Yaku, Hitoshi; Sakata, Ryuzo

    2017-07-25

    The aim of this study was to assess the long-term outcomes of aortic valve replacement (AVR) with either mechanical or bioprosthetic valves according to age at operation.Methods and Results:A total of 1,002 patients (527 mechanical valves and 475 bioprosthetic valves) undergoing first-time AVR were categorized according to age at operation: group Y, age mechanical and bioprosthetic valves for all age groups. Valve-related mortality was significantly higher for mechanical valves in group O (HR, 2.53; P=0.02). Reoperation rate was significantly lower for mechanical valves in group Y (HR, 0.16; Pmechanical valves). Although the rate of thromboembolic events was higher in mechanical valves in group Y (no events for tissue valves) and group M (HR, 9.05; P=0.03), there were no significant differences in bleeding events between all age groups. The type of prosthetic valve used in AVR does not significantly influence overall mortality.

  11. 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.

  12. Transcatheter Valve-in-Valve Implantation: Failing Tricuspid Bioprosthesis in a Patient with Ebstein’s Anomaly.

    Science.gov (United States)

    Villablanca, Pedro A; Shah, Aman M; Briceno, David F; Zaidi, Ali N; Chau, Mei; Garcia, Mario J; Slovut, David; Taub, Cynthia

    2017-01-01

    Transcatheter valve-in-valve (VIV) implantation has been recently proposed as an alternative to surgical reoperative aortic valve replacement in patients with a failing aortic bioprosthesis. Experience with transcatheter VIV implantation at other valve positions is very limited. Herein is reported the case of an 18-year-old man with Ebstein's anomaly and severe tricuspid valve (TV) regurgitation status after bioprosthetic valve replacement, who developed new dyspnea on exertion three years after the initial valve replacement. Transesophageal echocardiography showed a severely dilated right atrium and new TV stenosis with an immobile leaflet. The patient underwent successful VIV implantation of a 29-mm SAPIEN XT bioprosthetic valve, with resolution of symptoms and no residual TV regurgitation or stenosis at the two-year follow up. Video 1: Degenerative bioprosthetic tricuspid valve. TEE showing the degenerative bioprosthetic tricuspid valve, and color Doppler during systole showing severe tricuspid regurgitation. Video 2: Degenerative bioprosthetic tricuspid valve. Three-dimensional TEE showing stenosis with an immobile leaflet creating a coaptation defect, viewed from the right atrium. Video 3: Transcatheter VIV replacement with a 29-mm Edwards SAPIEN XT deployed within the tricuspid valve prosthesis. Final result after valve implantation, demonstrating a patent valve orifice, and appropriate apposition of transcatheter valve within a pre-existing surgical Carpentier-Edwards bioprosthetic valve, viewed from the right ventricle. Video 4: Transcatheter VIV replacement with a 29-mm Edwards SAPIEN XT deployed within the tricuspid valve prosthesis. Final result after valve implantation, demonstrating a patent valve orifice, and appropriate apposition of transcatheter valve within a pre-existing surgical Carpentier-Edwards bioprosthetic valve, viewed from the right atrium.

  13. 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.

  14. 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.

  15. Pattern and Extent of Tricuspid Valve Involvement in Chronic Rheumatic Heart Disease.

    Science.gov (United States)

    Rashid, M B; Parvin, T; Ahmed, C M; Islam, M J; Monwar, M M; Karmoker, K K; Parveen, R; Shakil, S S; Hasan, M N

    2018-01-01

    Rheumatic heart disease causes a significant number of morbidity and mortality in Bangladesh. Although the mitral and the aortic valve are the two most involved valves in rheumatic heart disease, the tricuspid valve disease is not uncommon secondary to, or in association with, mitral or aortic valve disease, but receives less attention as compared to the primary left-sided valve disease. Appropriate treatment of the tricuspid valve disease may improve long-term functional outcome. But the pattern and extent of the tricuspid valve involvement was not studied recently. This study was carried out to observe the pattern and extent of tricuspid valve involvement in Rheumatic Heart Disease patients. This observational analytical study was undertaken in the department of Cardiology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from December 2010 to September 2011. Considering all ethical issues, data were collected from 173 subjects who underwent Echocardiography for their Chronic Rheumatic heart disease. Pattern of tricuspid valve involvement was observed by using Transthoracic Echocardiography by 2D, M mode and Doppler assessment. One hundred seventy three (173) patients with Rheumatic Heart disease was studied, out of these, 36 patients had evidence of tricuspid valve involvement based on echocardiographic findings. Fifteen (15) patients had Tricuspid stenosis and 36 patients had Tricuspid Regurgitation in the patients with TV involvement. All the patients with TV involvement had thickened leaflets. Doming, restriction of motion and calcification were present in different proportions. From this study, it can be concluded that organic tricuspid valve involvement in RHD is not uncommon in our country.

  16. How to Make a Heart Valve: From Embryonic Development to Bioengineering of Living Valve Substitutes

    Science.gov (United States)

    MacGrogan, Donal; Luxán, Guillermo; Driessen-Mol, Anita; Bouten, Carlijn; Baaijens, Frank; de la Pompa, José Luis

    2014-01-01

    Cardiac valve disease is a significant cause of ill health and death worldwide, and valve replacement remains one of the most common cardiac interventions in high-income economies. Despite major advances in surgical treatment, long-term therapy remains inadequate because none of the current valve substitutes have the potential for remodeling, regeneration, and growth of native structures. Valve development is coordinated by a complex interplay of signaling pathways and environmental cues that cause disease when perturbed. Cardiac valves develop from endocardial cushions that become populated by valve precursor mesenchyme formed by an epithelial–mesenchymal transition (EMT). The mesenchymal precursors, subsequently, undergo directed growth, characterized by cellular compartmentalization and layering of a structured extracellular matrix (ECM). Knowledge gained from research into the development of cardiac valves is driving exploration into valve biomechanics and tissue engineering directed at creating novel valve substitutes endowed with native form and function. PMID:25368013

  17. 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.

  18. 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.

  19. Decellularized tissue-engineered heart valve leaflets with recellularization potential.

    Science.gov (United States)

    Syedain, Zeeshan H; Bradee, Allison R; Kren, Stefan; Taylor, Doris A; Tranquillo, Robert T

    2013-03-01

    Tissue-engineered heart valves (TEHV) have been proposed as a promising solution for the clinical needs of pediatric patients. In vivo studies have shown TEHV leaflet contraction and regurgitation after several months of implantation. This has been attributed to contractile cells utilized to produce the extracellular matrix (ECM) during TEHV culture. Here, we utilized such cells to develop a mature ECM in a fibrin-based scaffold that generates commissural alignment in TEHV leaflets and then removed these cells using detergents. Further, we evaluated recellularization with potentially noncontractile cells. A tissue-engineered leaflet model was developed with mechanical anisotropy and tensile properties comparable to an ovine pulmonary valve leaflet. No change in tensile properties occurred after decellularization using 1% sodium dodecyl sulfate and 1% Triton detergent treatment. Cell removal was verified by DNA quantitation and western blot analysis for cellular proteins. Histological and scanning electron microscope imaging showed no significant change in the ECM organization and microstructure. We further tested the recellularization potential of decellularized leaflets by seeding human mesenchymal stem cells (hMSC) on the surface of the leaflets and evaluated them at 1 and 3 weeks in two culture conditions. One medium (M1) was chosen to maintain the MSC phenotype while a second medium (M2) was used to potentially differentiate cells to an interstitial cell phenotype. Cellular quantitation showed that the engineered leaflets were recellularized to the highest concentration with M2 followed by M1, with minimum cell invasion of decellularized native leaflets. Histology showed cellular invasion throughout the thickness of the leaflets in M2 and partial invasion in M1. hMSC stained positive for MSC markers, but also for α-smooth muscle actin in both media at 1 week, with no presence of MSC markers at 3 weeks with the exception of CD90. These results show that

  20. Evaluation of prosthetic heart valves by transesophageal echocardiography: problems, pitfalls, and timing of echocardiography

    NARCIS (Netherlands)

    van den Brink, Renee B. A.

    2006-01-01

    Transesophageal echocardiography (TEE) is especially suitable for examination of prosthetic valves because of the proximity of the esophagus to the heart and absence of interference with lungs and ribs. This article reviews normal and abnormal morphologic characteristics of prosthetic valves such as

  1. Coronary artery assessment by multidetector computed tomography in patients with prosthetic heart valves

    NARCIS (Netherlands)

    Habets, Jesse; van den Brink, Renee B. A.; Uijlings, Ruben; Spijkerboer, Anje M.; Mali, Willem P. Th M.; Chamuleau, Steven A. J.; Budde, Ricardo P. J.

    2012-01-01

    Objectives Patients with prosthetic heart valves may require assessment for coronary artery disease. We assessed whether valve artefacts hamper coronary artery assessment by multidetector CT. Methods ECG-gated or -triggered CT angiograms were selected from our PACS archive based on the presence of

  2. 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......-time electrocardiography is seen in dogs with heart failure (HF) secondary to myxomatous mitral valve disease (MMVD). However, HRV is suggested to increase with disease severity at early stages of MMVD. The aims of this study were 1) to associate HR and HRV with severity of MMVD in Cavalier King Charles Spaniels (CKCS......) and 2) to compare HR and HRV between CKCS and other dog breeds in a group of dogs in HF secondary to MMVD. One-hundred dogs were examined by echocardiography and 24-hour electrocardiography. The dogs were divided into five groups: 1) CKCS with no/minimal mitral regurgitation (MR) (MR jet=15% of the left...

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

    International Nuclear Information System (INIS)

    Strong, M.; O'Neal, P.D.; Gage, H.N.; Moogk, M.

    1999-01-01

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

  4. 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...

  5. Heart Valves from Polyester Fibers vs. Biological Tissue: Comparative Study In Vitro.

    Science.gov (United States)

    Yousefi, Atieh; Vaesken, Antoine; Amri, Amna; Dasi, Lakshmi Prasad; Heim, Frederic

    2017-02-01

    Transcatheter aortic valve implantation (TAVI) has become a popular alternative technique to surgical valve replacement for critical patients. Biological valve tissue has been used in TAVI procedures for over a decade, with over 100,000 implantations to date. However, with only 6 years follow up, little is known about the long-term durability of biological tissue. Moreover, the high cost of tissue harvesting and chemical treatment procedures favor the development of alternative synthetic valve leaflet materials. Textile polyester is one such material which provides outstanding folding and strength properties combined with proven biocompatibility, and could therefore be considered as a candidate to replace the biological valve leaflets in TAVI procedures. For that purpose, in addition to the mechanical properties, the hemodynamic properties of the synthetic material should be comparable to the properties of biological tissue. An ideal replacement heart valve would provide low static and dynamic regurgitation, ensure laminar flow across the valve, and limit the turbidity of flow downstream of the valve. The purpose of the present work is to compare in vitro the mechanical and hemodynamic performances of textile woven polyester valves with biological ones. Testing results indicate that textile valves trade elasticity for superior mechanical strength, relative to biological tissue. Despite this, the dynamic flexibility of textile valve leaflets strongly resembled what was seen with biological leaflets. Regurgitation, as well as slightly modified turbulent patterns, in textile valves was higher than biological valves due to the increased porosity, but, rapid tissue ingrowth post-implantation would likely mitigate this effect. Together these findings provide additional evidence favoring the use of textile polyester as a synthetic heart valve leaflet material.

  6. Mitral Valve Prolapse

    Science.gov (United States)

    ... Aortic Valve Regurgitation - Problem: Mitral Valve Regurgitation - Problem: Tricuspid Valve Regurgitation - Problem: Pulmonary ... Heart Valve Disease Symptoms Dr. Robert Bonow describes the symptoms that ...

  7. A Structural Analysis of a Mechanical Heart Valve Prosthesis with Flat Leaflet

    Science.gov (United States)

    Kwon, Young Joo

    This paper addresses the basic concept of MDO methodology and the structural analysis that should be performed in the design process of a mechanical heart valve prosthesis with flat leaflet using MDO methodology. In the structural design of the mechanical heart valve (MHV) prosthesis, the fluid mechanics analysis is executed for the blood flow passing through the leaflets of a mechanical heart valve prosthesis. Thereafter, the rigid body dynamics analysis of the leaflet motion is performed to obtain the structural condition for the structural mechanics analysis of the deformed leaflet. Then the structural mechanics analysis of the deformed leaflet follows to confirm the minimum thickness of the leaflet for the structural durability of the mechanical heart valve prosthesis. This paper shows that the minimum leaflet thickness can be evaluated to be 0.6mm among the suggested thicknesses.

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

    Czech Academy of Sciences Publication Activity Database

    Klimeš, František; Kořenář, Josef

    2002-01-01

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

  9. Intermittent straining accelerates the development of tissue properties in engineered heart valve tissue

    NARCIS (Netherlands)

    Rubbens, M.P.; Mol, A.; Boerboom, R.A.; Bank, R.A.; Baaijens, F.P.T.; Bouten, C.V.C.

    2009-01-01

    Tissue-engineered heart valves lack sufficient amounts of functionally organized structures and consequently do not meet in vivo mechanical demands. To optimize tissue architecture and hence improve mechanical properties, various in vitro mechanical conditioning protocols have been proposed, of

  10. Holographic methods for quality monitoring and stress visualization in biological and mechanical prosthetic heart valves

    Science.gov (United States)

    Zarubin, Alexander M.; von Bally, Gert; Deiwick, M.; Geiger, A. W.; Scheld, H. H.

    1996-01-01

    A new application of holographic interferometry in biomedicine and bioengineering is presented. Holographic interferometry techniques for non-destructive testing and biomechanical evaluation of prosthetic heart valves are developed, and experimental results obtained with tissue and mechanical values are demonstrated.

  11. Bileaflet mechanical heart valve closing sounds: in vitro classification by phonocardiographic analysis.

    Science.gov (United States)

    Bagno, Andrea; Anzil, Federico; Buselli, Roberto; Pesavento, Elena; Tarzia, Vincenzo; Pengo, Vittorio; Bottio, Tomaso; Gerosa, Gino

    2009-01-01

    Bileaflet mechanical heart valves, which exhibit hemodynamic performance fairly similar to that of native valves, can be investigated by the analysis of their closing sounds. Signal spectra calculated from the closing sounds are characterized by specific features that are suitable for the functional evaluation of the valves. Five commercial bileaflet mechanical heart valves were studied under different conditions that were simulated in vitro using a Sheffield pulse duplicator for the aortic position. The closing sounds were acquired by means of a phonocardiographic apparatus, analyzed by a specifically implemented algorithm, and were statistically compared. This article was aimed at classifying the investigated valves on the basis of their signal spectra: different profiles were identified, depending on the working conditions; moreover, closing sound reproducibility and intensity allowed the ranking of valve performances with respect to the "noise" produced by valve closure. In particular, results demonstrated which valves were characterized by the lowest noise (i.e., the Medtronic Advantage and St. Jude Regent valves) and which were characterized by the highest reproducibility (OnX, Medtronic Advantage, and St. Jude Regent valves) under the examined experimental conditions.

  12. Current progress in tissue engineering of heart valves: multiscale problems, multiscale solutions.

    Science.gov (United States)

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

    2015-01-01

    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. 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. Whereas 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.

  13. 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 (Ptissue 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.

  14. Experimental study of physical properties of artificial materials for the development of the tissue-engineered valvular heart apparatus in comparison with biological analogs

    Science.gov (United States)

    Chiryatyeva, Aleksandra; Trebushat, Dmitry; Prokhorokhin, Aleksei; Khakhalkin, Vladimir; Andreev, Mark; Novokhreschenov, Aleksei; Kretov, Evgeny

    2017-12-01

    Cardiovascular diseases are the leading cause of death worldwide. Valvular heart disease often requires valve repair or replacement. Today, surgery uses xenograft—porcine or bovine pericardium. However, bioprosthetic valves do not ensure sufficient durability. We investigated 0.6% glutaraldehyde-treated porcine pericardium to define its properties. Using a tensile test stand, we studied characteristics of the polymeric material—expanded polytetrafluoroethylene (ePTFE)—and compared it to xenopericardium. The artificial material provides a better durability; it has higher elastic modulus and ultimate tensile strength. However, ePTFE samples demonstrated direction anisotropy due to extrusion features. It requires the enhancement of quality of the ePTFE sheet or investigation of other polymeric materials to find the adequate replacement for bioprosthetic heart valves.

  15. 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

  16. Heart valve cardiomyocytes of mouse embryos express the serotonin transporter SERT

    International Nuclear Information System (INIS)

    Pavone, Luigi Michele; Spina, Anna; Lo Muto, Roberta; Santoro, Dionea; Mastellone, Vincenzo; Avallone, Luigi

    2008-01-01

    Multiple evidence demonstrate a role for serotonin and its transporter SERT in heart valve development and disease. By utilizing a Cre/loxP system driven by SERT gene expression, we recently demonstrated a regionally restricted distribution of SERT-expressing cells in developing mouse heart. In order to characterize the cell types exhibiting SERT expression within the mouse heart valves at early developmental stages, in this study we performed immunohistochemistry for Islet1 (Isl1) and connexin-43 (Cx-43) on heart sections from SERT Cre/+ ;ROSA26R embryos previously stained with X-gal. We observed the co-localization of LacZ staining with Isl1 labelling in the outflow tract, the right ventricle and the conal region of E11.5 mouse heart. Cx-43 labelled cells co-localized with LacZ stained cells in the forming atrioventricular valves. These results demonstrate the cardiomyocyte phenotype of SERT-expressing cells in heart valves of the developing mouse heart, thus suggesting an active role of SERT in early heart valve development.

  17. 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

    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......dogs; even prior to the development of overt congestive heart failure....... 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...

  18. 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.

  19. Developing a Clinically Relevant Tissue Engineered Heart Valve-A Review of Current Approaches.

    Science.gov (United States)

    Nachlas, Aline L Y; Li, Siyi; Davis, Michael E

    2017-12-01

    Tissue engineered heart valves (TEHVs) have the potential to address the shortcomings of current implants through the combination of cells and bioactive biomaterials that promote growth and proper mechanical function in physiological conditions. The ideal TEHV should be anti-thrombogenic, biocompatible, durable, and resistant to calcification, and should exhibit a physiological hemodynamic profile. In addition, TEHVs may possess the capability to integrate and grow with somatic growth, eliminating the need for multiple surgeries children must undergo. Thus, this review assesses clinically available heart valve prostheses, outlines the design criteria for developing a heart valve, and evaluates three types of biomaterials (decellularized, natural, and synthetic) for tissue engineering heart valves. While significant progress has been made in biomaterials and fabrication techniques, a viable tissue engineered heart valve has yet to be translated into a clinical product. Thus, current strategies and future perspectives are also discussed to facilitate the development of new approaches and considerations for heart valve tissue engineering. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Directory of Open Access Journals (Sweden)

    Tamatey Martin

    2011-04-01

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

  1. 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.

  2. 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, 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.

  3. Detergent-based decellularization strategy preserves macro- and microstructure of heart valves.

    Science.gov (United States)

    Haupt, Jessica; Lutter, Georg; Gorb, Stanislav N; Simionescu, Dan T; Frank, Derk; Seiler, Jette; Paur, Alina; Haben, Irma

    2018-02-01

    Biological tissue has great potential to function as bioprostheses in patients for heart valve replacement. As these matrices are mainly xenogenic, the immunogenicity needs to be reduced by decellularization steps. Reseeding of bioscaffolds has tremendous potential to prevent calcification upon implantation, so intact microstructure of the material is mandatory. An optimal decellularization protocol of heart valves resulting in adequate preservation of the extracellular architecture has still not been developed. Biological scaffolds must be decellularized to remove the antigenic potential while preserving the complex mixture of structural and functional proteins that constitute the extracellular matrix. Here, we compared 3 different decellularization strategies for their efficiency to remove cells completely while preserving the porcine heart valve ultrastructure. Porcine pulmonary heart valves were treated either with trypsin-ethylenediaminetetraacetic acid (TRP), a protocol using detergents in combination with nucleases (DET + ENZ), or with Accutase® solution followed by nuclease treatment (ACC + ENZ). The treated heart valves then were subjected to histological, DNA and scanning electron microscopic analyses. All DNA fragments were removed after ACC + ENZ treatment, whereas cellular removal was incomplete in the TRP group. TRP and ACC + ENZ-treated valves were enlarged and showed a disrupted architecture and degraded ultrastructure. In contrast, fully acellular heart valves with intact architecture, layer composition and surface topography were achieved with DET + ENZ treatment. DET + ENZ treatment yielded excellent results in terms of preservation of material architecture and removal of DNA content. Compared to TRP and ACC + ENZ procedures, DET + ENZ-treated porcine pulmonary heart valves demonstrated well-preserved macroscopic structures and microscopic matrix components and represent an excellent scaffold for further

  4. Cardiac resynchronization therapy improved heart failure after left bundle branch block during transcatheter aortic valve implantation.

    Science.gov (United States)

    Meguro, Kentaro; Lellouche, Nicolas; Teiger, Emmanuel

    2012-03-01

    After transcatheter aortic valve implantation (TAVI) in a 75-year-old male, chronic wide left bundle branch block (LBBB) developed. He experienced repeated episodes of decompensated systolic heart failure with severe systolic left ventricular dysfunction. After cardiac resynchronization therapy, his heart function improved substantially and he had no further admissions for heart failure. Cardiac resynchronization therapy can be effective in systolic heart failure associated with LBBB developing after TAVI.

  5. 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

  6. Transforming growth factor Beta2 is required for valve remodeling during heart development

    Science.gov (United States)

    Azhar, Mohamad; Brown, Kristen; Gard, Connie; Chen, Hwudaurw; Rajan, Sudarsan; Elliott, David A.; Stevens, Mark V.; Camenisch, Todd D.; Conway, Simon J.; Doetschman, Thomas

    2012-01-01

    Although the function of transforming growth factor beta2 (TGFβ2) in epithelial mesenchymal transition (EMT) is well studied, its role in valve remodeling remains to be fully explored. Here, we used histological, morphometric, immunohistochemical and molecular approaches and showed that significant dysregulation of major extracellular matrix (ECM) components contributed to valve remodeling defects in Tgfb2-/- embryos. The data indicated that cushion mesenchymal cell differentiation was impaired in Tgfb2-/- embryos. Hyaluronan and cartilage link protein-1 (CRTL1) were increased in hyperplastic valves of Tgfb2-/- embryos, indicating increased expansion and diversification of cushion mesenchyme into the cartilage cell lineage during heart development. Finally, western blot and immunohistochemistry analyses indicate that the activation of SMAD2/3 was decreased in Tgfb2-/- embryos during valve remodeling. Collectively, the data indicate that TGFβ2 promotes valve remodeling and differentiation by inducing matrix organization and suppressing cushion mesenchyme differentiation into cartilage cell lineage during heart development. PMID:21780244

  7. Galnt1 Is Required for Normal Heart Valve Development and Cardiac Function

    Science.gov (United States)

    Tian, E; Stevens, Sharon R.; Guan, Yu; Springer, Danielle A.; Anderson, Stasia A.; Starost, Matthew F.; Patel, Vyomesh; Ten Hagen, Kelly G.; Tabak, Lawrence A.

    2015-01-01

    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. PMID:25615642

  8. Implantation of a Tissue-Engineered Tubular Heart Valve in Growing Lambs.

    Science.gov (United States)

    Reimer, Jay; Syedain, Zeeshan; Haynie, Bee; Lahti, Matthew; Berry, James; Tranquillo, Robert

    2017-02-01

    Current pediatric heart valve replacement options are suboptimal because they are incapable of somatic growth. Thus, children typically have multiple surgeries to replace outgrown valves. In this study, we present the in vivo function and growth potential of our tissue-engineered pediatric tubular valve. The valves were fabricated by sewing two decellularized engineered tissue tubes together in a prescribed pattern using degradable sutures and subsequently implanted into the main pulmonary artery of growing lambs. Valve function was monitored using periodic ultrasounds after implantation throughout the duration of the study. The valves functioned well up to 8 weeks, 4 weeks beyond the suture strength half-life, after which their insufficiency index worsened. Histology from the explanted valves revealed extensive host cell invasion within the engineered root and commencing from the leaflet surfaces. These cells expressed multiple phenotypes, including endothelial, and deposited elastin and collagen IV. Although the tubes fused together along the degradable suture line as designed, the leaflets shortened compared to their original height. This shortening is hypothesized to result from inadequate fusion at the commissures prior to suture degradation. With appropriate commissure reinforcement, this novel heart valve may provide the somatic growth potential desired for a pediatric valve replacement.

  9. 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

  10. Prenatally engineered autologous amniotic fluid stem cell-based heart valves in the fetal circulation.

    Science.gov (United States)

    Weber, Benedikt; Emmert, Maximilian Y; Behr, Luc; Schoenauer, Roman; Brokopp, Chad; Drögemüller, Cord; Modregger, Peter; Stampanoni, Marco; Vats, Divya; Rudin, Markus; Bürzle, Wilfried; Farine, Marc; Mazza, Edoardo; Frauenfelder, Thomas; Zannettino, Andrew C; Zünd, Gregor; Kretschmar, Oliver; Falk, Volkmar; Hoerstrup, Simon P

    2012-06-01

    Prenatal heart valve interventions aiming at the early and systematic correction of congenital cardiac malformations represent a promising treatment option in maternal-fetal care. However, definite fetal valve replacements require growing implants adaptive to fetal and postnatal development. The presented study investigates the fetal implantation of prenatally engineered living autologous cell-based heart valves. Autologous amniotic fluid cells (AFCs) were isolated from pregnant sheep between 122 and 128 days of gestation via transuterine sonographic sampling. Stented trileaflet heart valves were fabricated from biodegradable PGA-P4HB composite matrices (n = 9) and seeded with AFCs in vitro. Within the same intervention, tissue engineered heart valves (TEHVs) and unseeded controls were implanted orthotopically into the pulmonary position using an in-utero closed-heart hybrid approach. The transapical valve deployments were successful in all animals with acute survival of 77.8% of fetuses. TEHV in-vivo functionality was assessed using echocardiography as well as angiography. Fetuses were harvested up to 1 week after implantation representing a birth-relevant gestational age. TEHVs showed in vivo functionality with intact valvular integrity and absence of thrombus formation. The presented approach may serve as an experimental basis for future human prenatal cardiac interventions using fully biodegradable autologous cell-based living materials. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Tissue-engineered heart valves develop native-like collagen fiber architecture.

    Science.gov (United States)

    Cox, Martijn A J; Kortsmit, Jeroen; Driessen, Niels; Bouten, Carlijn V C; Baaijens, Frank P T

    2010-05-01

    Creating autologous tissues with on-demand and native-like biomechanical properties is the ultimate challenge in functional heart valve tissue engineering. A promising approach toward this goal is to induce development of native-like tissue structure in vitro by mimicking the diastolic loading phase in a bioreactor. Heart valves cultured with this approach showed in vitro sufficient strength to withstand systemic pressures. This study aims to link global functioning of these valves to the development of a native-like fiber architecture induced by in vitro diastolic loading. It is hypothesized that increased loading magnitude during culture will lead to increased collagen fiber alignment. To test this hypothesis, 10 tissue-engineered heart valves were subjected to different loading protocols in vitro. Local fiber distribution and mechanics were determined in an inverse numerical-experimental approach, combining indentation tests with confocal imaging. Indentation tests on native ovine heart valves were used as a comparison. Although the effect of loading magnitude was small within the tested range, results indicated that the local fiber architecture indeed developed toward native structural properties for all loading protocols. However, apparent fiber mechanics were much stiffer compared with native. This confirms that in vitro mechanical conditioning induces development of a native-like tissue architecture, which underlines its importance for functional heart valve tissue engineering.

  12. In vitro investigation of prosthetic heart valves in magnetic resonance imaging: evaluation of potential hazards.

    Science.gov (United States)

    Pruefer, D; Kalden, P; Schreiber, W; Dahm, M; Buerke, M; Thelen, M; Oelert, H

    2001-05-01

    Magnetic resonance (MR) imaging is used in an increasing number of patients, and not only after cardiac valve replacement. However, ferromagnetic biomedical implants are often considered a contraindication for MR imaging because of the potential hazards with respect to their movement, dislodgement, or heating effects during the procedure. The purpose of this study was to assess ferromagnetism, attraction forces, heating effects, and artifacts associated with prosthetic heart valve implants. Seventeen common heart valve prostheses (12 mechanical, five biological) were examined in vitro using a high-field-strength 1.5 Tesla (T) MR system. Attractive forces, temperature changes and the amount of artifacts were assessed by applying turbo-spin and gradient-echo sequences. The maximal calculated corresponding ferromagnetic force was (0.22 x 10(-3) N) in the static magnetic field. The temperature changes ranged from 0 to 0.5 degrees C maximum. Artifacts produced by the presence of the heart valve prostheses were less evident using a spin-echo sequence than a gradient-echo sequence. MR imaging exerted no significant force on the examined heart valve prostheses, and did not result in significant biological relevant temperature increase. None of the associated artifacts is considered to pose a substantial risk on MR imaging. MR procedures performed with a 1.5 T MR system can be applied safely in patients with heart valve prostheses evaluated in this study.

  13. A review of: application of synthetic scaffold in tissue engineering heart valves.

    Science.gov (United States)

    Fallahiarezoudar, Ehsan; Ahmadipourroudposht, Mohaddeseh; Idris, Ani; Mohd Yusof, Noordin

    2015-03-01

    The four heart valves represented in the mammalian hearts are responsible for maintaining unidirectional, non-hinder blood flow. The heart valve leaflets synchronically open and close approximately 4 million times a year and more than 3 billion times during the life. Valvular heart dysfunction is a significant cause of morbidity and mortality around the world. When one of the valves malfunctions, the medical choice is may be to replace the original valves with an artificial one. Currently, the mechanical and biological artificial valves are clinically used with some drawbacks. Tissue engineering heart valve concept represents a new technique to enhance the current model. In tissue engineering method, a three-dimensional scaffold is fabricated as the template for neo-tissue development. Appropriate cells are seeded to the matrix in vitro. Various approaches have been investigated either in scaffold biomaterials and fabrication techniques or cell source and cultivation methods. The available results of ongoing experiments indicate a promising future in this area (particularly in combination of bone marrow stem cells with synthetic scaffold), which can eliminate the need for lifelong anti-coagulation medication, durability and reoperation problems. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Diseases of the Tricuspid Valve

    Science.gov (United States)

    ... Valve Menu Topics Topics FAQs Diseases of the Tricuspid Valve Diseases of the heart valves are grouped according to ... heart valves , tricuspid incompetence , tricuspid insufficiency , tricuspid regurgitation , tricuspid ... Links MedlinePlus | Tricuspid Regurgitation Valve Disease Valve ...

  15. Computed tomography characteristics of the aortic valve and the geometry of SAPIEN 3 transcatheter heart valve in patients with bicuspid aortic valve disease.

    Science.gov (United States)

    Kawamori, Hiroyuki; Yoon, Sung-Han; Chakravarty, Tarun; Maeno, Yoshio; Kashif, Mohammad; Israr, Sharjeel; Abramowitz, Yigal; Mangat, Geeteshwar; Miyasaka, Masaki; Rami, Tanya; Kazuno, Yoshio; Takahashi, Nobuyuki; Jilaihawi, Hasan; Nakamura, Mamoo; Cheng, Wen; Friedman, John; Berman, Daniel; Sharma, Rahul; Makkar, Raj R

    2018-01-05

    We assessed the geometry of transcatheter heart valve (THV) and valve function associated with SAPIEN 3 implantation in patients with bicuspid aortic valve (BAV) stenosis. We included 280 consecutive patients who had a contrast computed tomography (CT) before and after transcatheter aortic valve implantation (TAVI) in our institution. Each THV was assessed by CT at five cross-sectional levels: inflow, annulus, mid, sinus, and outflow. The geometry of THV was assessed for eccentricity (1 - minimum diameter/maximum diameter) and expansion (CT derived external valve area/nominal external valve area). CT measurements and transthoracic echocardiogram data were compared between BAV and tricuspid aortic valve (TAV). Among 280 patients, 41 patients were diagnosed as BAV. Compared to TAV, BAV was associated with lower expansion at mid-level, sinus-level, and outflow-level (mid 94.1 ± 6.8% vs. 98.1 ± 7.8%; P = 0.002, sinus 95.9 ± 7.2% vs. 101.6 ± 8.5%; P 4.0-11.4); P < 0.001, and outflow 2.5% (1.3-4.3) vs. 4.9% (2.2-7.5); P < 0.001]. There were no differences in frequency of paravalvular leak ≥ moderate and mean post-procedural gradient between BAV and TAV. BAV patients have greater THV eccentricity at all levels and lower THV expansion at mid, sinus, and outflow levels than the TAV patients. There were no differences in parameters of valve function between BAV and TAV patients. Despite the observed geometrical differences, TAVI with SAPIEN 3 in BAV patients allows for feasible valve function. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2018. For permissions, please email: journals.permissions@oup.com.

  16. 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.

  17. Heart valve disease among patients with hyperprolactinemia: a nationwide population-based cohort study.

    Science.gov (United States)

    Steffensen, Charlotte; Maegbaek, Merete Lund; Laurberg, Peter; Andersen, Marianne; Kistorp, Caroline Micheala Nervil; Norrelund, Helene; Sørensen, Henrik Toft; Jorgensen, Jens Otto Lunde

    2012-05-01

    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. The objective of the study was to assess the incidence of diagnosed heart valve disease and cardiac valve surgery among patients with hyperprolactinemia, compared with a general population cohort in Denmark. This was a nationwide, population-based, cohort study based on a nationwide hospital registry. We identified 2381 hyperprolactinemia patients with a first-time diagnosis recorded from 1994 through 2010 in the registry, with no previous hospital diagnosis of heart valve disease. Each patient was compared with 10 age- and gender-matched comparison cohort members from the general population. The association between hyperprolactinemia and heart valve disease was analyzed with Cox's proportional hazards regression, controlling for potential confounding factors. To assess the risk of cardiac valve surgery and avoid ascertainment bias, a subanalysis was made in a cohort of 2,387 hyperprolactinemia patients with no previous cardiac valve surgery and 23,870 comparison cohort members. Nineteen hyperprolactinemic patients (0.80%) were diagnosed with heart valve disease during a total of 17,759.8 yr of follow-up, compared with 75 persons (0.31%) in the comparison cohort during 179,940.6 yr of follow-up [adjusted hazard ratio 2.27 (95% confidence interval 1.35-3.82)]. Seven of the 10 patients treated with cabergoline and diagnosed with heart valve disease were asymptomatic and diagnosed on the basis of an echocardiography performed as a safety measure. However, only two patients with hyperprolactinemia (0.08%) underwent surgery, compared with 28 persons in the general population cohort (0.12%) [adjusted hazard ratio 0.55 (95% confidence interval 0.13-2.42)]. Data from the present

  18. Use of human umbilical cord blood-derived progenitor cells for tissue-engineered heart valves.

    Science.gov (United States)

    Sodian, Ralf; Schaefermeier, Philipp; Abegg-Zips, Sybille; Kuebler, Wolfgang M; Shakibaei, Mehdi; Daebritz, Sabine; Ziegelmueller, Johannes; Schmitz, Christoph; Reichart, Bruno

    2010-03-01

    Tissue engineering of autologous heart valves with the potential to grow and to remodel represents a promising concept. Here we describe the use of cryopreserved umbilical cord blood-derived CD133(+) cells as a single cell source for the tissue engineering of heart valves. After expansion and differentiation of CD133(+) cells, phenotypes were analyzed by immunohistochemistry and cryopreserved. Heart valve scaffolds fabricated from a biodegradable polymer (n = 8) were seeded with blood-derived myofibroblasts and subsequently coated with blood-derived endothelial cells. Afterward, the heart valve constructs were grown in a pulse duplicator system. Analysis of all heart valves, including histology, immunohistochemistry, electron microscopy, fluorescence imaging, and biochemical and biomechanical examination, was performed. The tissue-engineered heart valves showed endothelialized layered tissue formation including connective tissue between the inside and the outside of the scaffold. The notion of an intact endothelial phenotype was substantiated by fluorescence imaging studies of cellular nitric oxide production and Ca(2+) signaling. Electron microscopy showed that the cells had grown into the pores and formed a confluent tissue layer. Biochemical examination showed extracellular matrix formation (77% +/- 9% collagen of human pulmonary leaflet tissue [HPLT], 85% +/- 61% glycosaminoglycans of HPLT and 67% +/- 17% elastin of HPLT). Importantly, this study demonstrates in vitro generation of viable human heart valves based on CD133(+) cells derived from umbilical cord blood. These findings constitute a significant step forward in the development of new clinical strategies for the treatment of congenital defects. 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  19. 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

  20. 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.

  1. Decellularized xenogenic heart valves reveal remodeling and growth potential in vivo.

    Science.gov (United States)

    Erdbrügger, Wilhelm; Konertz, Wolfgang; Dohmen, Pascal M; Posner, Steffen; Ellerbrok, Heinz; Brodde, Otto-Erich; Robenek, Horst; Modersohn, Diethelm; Pruss, Axel; Holinski, Sebastian; Stein-Konertz, Marita; Pauli, Georg

    2006-08-01

    We have developed an advanced tissue processing technique on porcine pulmonary heart valves for pulmonary valve replacement and its initial clinical application during the autograft operation according to Ross. The novel concept consists of a cell-free matrix achieved by deoxycholic acid treatment that is repopulated by host cells in vivo. Molecular biology, radioligand binding, and electron microscopy consistently showed that these valves are almost free of cellular components. Animal experiments and clinical investigations revealed excellent hemodynamic properties of the valves, no need for antithrombotic therapy, and repopulation by host cells without any signs of calcification. In juvenile sheep the internal diameter of the implanted valves significantly increased in growing animals by approximately 10 mm. The repopulation of the decellularized heart valves was found not only in sheep but also in humans, which indicates that the underlying mechanisms, presumably repair mechanisms, might be common in mammals. If these findings can be confirmed by others, they will lead to new concepts in the field of cardiovascular tissue engineering that will eliminate the need for in vitro construction of autologous heart valves.

  2. 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...

  3. RNA-Seq Analysis to Identify Novel Roles of Scleraxis during Embryonic Mouse Heart Valve Remodeling

    Science.gov (United States)

    Wu, Yonggan; Willoughby, David A.; Lincoln, Joy

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Damien N Barnette

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

  5. Hypoplastic right heart syndrome, absent pulmonary valve, and non-compacted left ventricle in an adult

    Directory of Open Access Journals (Sweden)

    Jagdish C. Mohan

    2016-09-01

    Full Text Available Hypoplastic right heart syndrome is a rare cyanotic congenital heart disease with under-development of the right ventricle, tricuspid, and pulmonary valves leading to right-to-left shunting of the blood through inter-atrial septal defect. Perinatal mortality is high with very few patients surviving to adulthood without corrective surgery. This report describes a 26-year-old young woman, who had recurrent abortions and stillbirths and detected to have marked cyanosis with hypoplastic right heart, sub-arterial ventricular septal defect, absent pulmonary valve, non-compaction of the left ventricle, and bicuspid aortic valve with aortic regurgitation. The patient died owing to progressive heart failure 4 years after the diagnosis was made.

  6. 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...... Sciences, University of Copenhagen, Frederiksberg, Denmark, 2Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden; and 3Novo Nordic A/S, Maaloev, Denmark. Introduction: Modulation of heart rate by the autonomic nervous system can indirectly be measured by heart rate...... 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...

  7. Acoustical analysis of mechanical heart valve sounds for early detection of malfunction.

    Science.gov (United States)

    Famaey, Nele; Defever, Korijn; Bielen, Paul; Flameng, Willem; Vander Sloten, Jos; Sas, Paul; Meuris, Bart

    2010-10-01

    Mechanical heart valves carry the disadvantage of lifelong antithrombotic therapy, due to the high risk of thrombus formation on the valve surface. Current diagnostic methods are incapable of detecting thrombus formation in an early stage. This article investigates a new diagnostic method, based on the analysis of the acoustic signal produced by the valve. This method should be capable of early detection of malfunction, thus permitting targeted medication and reducing valve-related complications and mortality. A measurement setup assuring optimal signal quality was developed, and a signal analysis program was implemented and validated on an in vitro mock circulatory loop. Next, four sheep were implanted with a bileaflet mechanical valve. The signals of their valves developing thrombosis were assessed on a weekly basis before explantation. Three sheep were sacrificed shortly after detection of malfunction according to the newly developed method. In each case, thrombus or membrane formation was detected on the leaflets upon explantation. In one sheep, no malfunction was found in the analysis, which was also confirmed by the condition of the valve upon explantation. These preliminary results indicate that acoustical analysis of mechanical heart valves permits early detection of valvular malfunction. Further research with more in vitro and animal testing is required to statistically validate these findings. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

  8. Assessment of heart valve performance by finite-element design studies of polymeric leaflet-structures

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    Pfensig Sylvia

    2017-09-01

    Full Text Available For the treatment of severe symptomatic aortic valve stenosis, minimally invasive heart valve prostheses are increasingly used, especially for elderly patients. The current generation of devices is based on xenogenic leaflet material, involving limitations with regard to calcification and durability. Artificial polymeric leaflet-structures re-present a promising approach for improvement of valve performance. Within the current work, finite-element ana-lysis (FEA design studies of polymeric leaflet structures were conducted. Design of an unpressurized and axially-symmetric trileaflet heart valve was developed based on nine parameters. Physiological pressurization in FEA was specified, based on in vitro hydrodynamic testing of a commercially available heart valve prosthesis. Hyper-elastic constitutive law for polymeric leaflet material was implemented based on experimental stress strain curves resulting from uniaxial tensile and planar shear testing. As a result of FEA, time dependent leaflet deformation of the leaflet structure was calculated. Obtained leaflet dynamics were comparable to in vitro performance of the analyzed prosthesis. As a major design parameter, the lunula angle has demonstrated crucial influence on the performance of the polymeric leaflet structures. FEA represented a useful tool for design of improved polymeric leaflet structures for minimally invasive implantable heart valve prostheses.

  9. Hypoxia induces near-native mechanical properties in engineered heart valve tissue.

    Science.gov (United States)

    Balguid, Angelique; Mol, Anita; van Vlimmeren, Marijke A A; Baaijens, Frank P T; Bouten, Carlijn V C

    2009-01-20

    Previous attempts in heart valve tissue engineering (TE) failed to produce autologous valve replacements with native-like mechanical behavior to allow for systemic pressure applications. Because hypoxia and insulin are known to promote protein synthesis by adaptive cellular responses, a physiologically relevant oxygen tension and insulin supplements were applied to the growing heart valve tissues to enhance their mechanical properties. Scaffolds of rapid-degrading polyglycolic acid meshes coated with poly-4-hydroxybutyrate were seeded with human saphenous vein myofibroblasts. The tissue-engineered constructs were cultured under normal oxygen tension (normoxia) or hypoxia (7% O(2)) and incubated with or without insulin. Glycosaminoglycan production in the constructs approached that of native values under the influence of hypoxia and under the influence of insulin. Both insulin and hypoxia were associated with enhanced matrix production and improved mechanical properties; however, a synergistic effect was not observed. Although the amount of collagen and cross-links in the engineered tissues was still lower than that in native adult human aortic valves, constructs cultured under hypoxic conditions reached native human aortic valve levels of tissue strength and stiffness after 4 weeks of culturing. These results indicate that oxygen tension may be a key parameter for the achievement of sufficient tissue quality and mechanical integrity in tissue-engineered heart valves. Engineered tissues of such strength, based on rapid-degrading polymers, have not been achieved to date. These findings bring the potential use of tissue-engineered heart valves for systemic applications a step closer and represent an important improvement in heart valve tissue engineering.

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

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    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

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

    Science.gov (United States)

    Fang, Ning-Tao; Xie, Shang-Zhe; Wang, Song-Mei; Gao, Hong-Yang; Wu, Chun-Gen; Pan, Luan-Feng

    2007-04-20

    Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. This study was designed to develop a tissue engineering heart valve by using human umbilical cord blood-derived endothelial progenitor cells (EPCs) and decellularized valve scaffolds. Decellularized valve scaffolds were prepared from fresh porcine heart valves. EPCs were isolated from fresh human umbilical cord blood by density gradient centrifugation, cultured for 3 weeks in EGM-2-MV medium, by which time the resultant cell population became endothelial in nature, as assessed by immunofluorescent staining. EPC-derived endothelial cells were seeded onto the decellularized scaffold at 3 x 10(6) cells/cm(2) and cultured under static conditions for 7 days. Proliferation of the seeded cells on the scaffolds was detected using the MTT assay. Tissue-engineered heart valves were analyzed by HE staining, immunofluorescent staining and scanning electron microscopy. The anti-thrombogenic function of the endothelium on the engineered heart valves was evaluated by platelet adhesion experiments and reverse transcription-polymerase chain reaction (RT-PCR) analysis for the expression of endothelial nitric oxide synthase (eNOS) and tissue-type plasminogen activator (t-PA). EPC-derived endothelial cells showed a histolytic cobblestone morphology, expressed specific markers of the endothelial cell lineage including von Willebrand factor (vWF) and CD31, bound a human endothelial cell-specific lectin, Ulex Europaeus agglutinin-1 (UEA-1), and took up Dil-labeled low density lipoprotein (Dil-Ac-LDL). After seeding on the decellularized scaffold, the cells showed excellent metabolic activity and proliferation. The cells formed confluent endothelial monolayers atop the decellularized matrix, as assessed by HE staining and immunostaining for vWF and CD31. Scanning electron microscopy demonstrated the occurrence of tight junctions between cells forming the confluent monolayer

  12. 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

    2017-01-01

    Objective The goal of this research project encompasses finding the most efficient and effective method of decellularized tissue sterilization. Background 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. Methods 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. Results 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). Conclusions 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. 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

  13. A computational model of aging and calcification in the aortic heart valve.

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    Eli J Weinberg

    Full Text Available The aortic heart valve undergoes geometric and mechanical changes over time. The cusps of a normal, healthy valve thicken and become less extensible over time. In the disease calcific aortic stenosis (CAS, calcified nodules progressively stiffen the cusps. The local mechanical changes in the cusps, due to either normal aging or pathological processes, affect overall function of the valve. In this paper, we propose a computational model for the aging aortic valve that connects local changes to overall valve function. We extend a previous model for the healthy valve to describe aging. To model normal/uncomplicated aging, leaflet thickness and extensibility are varied versus age according to experimental data. To model calcification, initial sites are defined and a simple growth law is assumed. The nodules then grow over time, so that the area of calcification increases from one model to the next model representing greater age. Overall valve function is recorded for each individual model to yield a single simulation of valve function over time. This simulation is the first theoretical tool to describe the temporal behavior of aortic valve calcification. The ability to better understand and predict disease progression will aid in design and timing of patient treatments for CAS.

  14. 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.

  15. Two-dimensional FSI simulation of closing dynamics of a tilting disc mechanical heart valve.

    Science.gov (United States)

    Govindarajan, V; Udaykumar, H S; Herbertson, L H; Deutsch, S; Manning, K B; Chandran, K B

    2010-03-01

    The fluid dynamics during valve closure resulting in high shear flows and large residence times of particles has been implicated in platelet activation and thrombus formation in mechanical heart valves. Our previous studies with bi-leaflet valves have shown that large shear stresses induced in the gap between the leaflet edge and the valve housing results in relatively high platelet activation levels whereas flow between the leaflets results in shed vortices not conducive to platelet damage. In this study we compare the result of closing dynamics of a tilting disc valve with that of a bi-leaflet valve. The two-dimensional fluid-structure interaction analysis of a tilting disc valve closure mechanics is performed with a fixed grid Cartesian mesh flow solver with local mesh refinement, and a Lagrangian particle dynamic analysis for computation of potential for platelet activation. Throughout the simulation the flow remains in the laminar regime and the flow through the gap width is marked by the development of a shear layer which separates from the leaflet downstream of the valve. Zones of re-circulation are observed in the gap between the leaflet edge and the valve housing on the major orifice region of the tilting disc valve and are seen to be migrating towards the minor orifice region. Jet flow is observed at the minor orifice region and a vortex is formed which sheds in the direction of fluid motion as observed in experiments using PIV measurements. The activation parameter computed for the tilting disc valve, at the time of closure was found to be 2.7 times greater than that of the bi-leaflet mechanical valve and was found to be in the vicinity of the minor orifice region mainly due to the migration of vortical structures from the major to the minor orifice region during the leaflet rebound of the closing phase.

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

    Science.gov (United States)

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

    2010-08-15

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

  17. Incidência de trombo intracardíaco e de tromboembolismo nos três primeiros meses após o implante de bioprótese valvar Incidence of intracardiac thrombus and thromboembolism in the first three months after bioprosthetic valve implantation

    Directory of Open Access Journals (Sweden)

    Auristela Isabel de Oliveira Ramos

    2004-12-01

    Full Text Available OBJETIVO: Avaliar a incidência de trombo intracardíaco e de tromboembolismo nos três primeiros meses após a troca valvar por bioprótese e identificar fatores de risco para a formação de trombo. MÉTODO:Incluídos 184 pacientes, entre 15 e 75 anos de idade, submetidos a implante de bioprótese e realizados ecocardiogramas transtorácico e transesofágico (ETE na fase hospitalar, média 8,4±3 dias, e três meses após, média 97,4±21,7 dias. RESULTADOS: Incidência de trombo foi significativamente mais elevada nos pacientes com prótese em posição mitral ou mitroaórtica (21,0% do que em posição aórtica (2,8%, pOBJECTIVE: To assess the incidence of intracardiac thrombus and thromboembolism in the first 3 months after bioprosthetic valve replacement and to identify the risk factors for thrombus formation. METHODS: The study comprised 184 patients, aged between 15 and 75 years, who underwent bioprosthetic valve implantation. Transthoracic and transesophageal (TEE echocardiographies were performed in the in-hospital phase (mean, 8.4±3 days and after 3 months (mean, 97.4±21.7 days. RESULTS: The incidence of thrombus was significantly greater in patients with a prosthesis in the mitral or mitroaortic position (21.0% than in those with a prosthesis in the aortic position (2.8%, P<0.001. The multiple logistic regression identified the prosthesis in the mitral or mitroaortic position as the only independent variable for thrombus formation. On the 3-month follow-up, TEE showed a thrombus in 35 (20.7% of the 169 patients on echocardiographic assessment, 31.7% in mitral patients and 3.1% in aortic patients, P<0.001. In the third month, the multiple logistic regression also identified the prosthesis in the mitral or mitroaortic position as the only independent variable for thrombus formation. During the 3-month follow-up, 3 (1.6% patients died and 8 (4.3% experienced embolic phenomena, all in the cerebral territory. CONCLUSION: The incidence

  18. 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

  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. 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.

  1. Orthotopic replacement of aortic heart valves with tissue-engineered grafts.

    Science.gov (United States)

    Tudorache, Igor; Calistru, Alex; Baraki, Hassina; Meyer, Tanja; Höffler, Klaus; Sarikouch, Samir; Bara, Christopher; Görler, Adelheid; Hartung, Dagmar; Hilfiker, Andres; Haverich, Axel; Cebotari, Serghei

    2013-08-01

    Heart valve tissue engineering aims to create a graft with improved durability compared to routinely used valve substitutes. This study presents the function and morphological changes of a tissue-engineered aortic valve (TEV) compared to the cryopreserved valve (CPV), aortic valve (AV) allografts in an orthotopic position in sheep. Ovine AV conduits (n=5) were decellularized with detergents. Autologous endothelial cells (ECs) were seeded onto the valve surface and cultured under physiological conditions using a high pulsatile flow. Grafts were implanted as a root with reimplantation of coronary ostia in sheep. Crystalloid cardioplegia and isogenic blood transfusions from previous sacrificed sheep were used. Only antiplatelet aggregation therapy was used postoperatively. CPVs (n=4) served as controls. The grafts were investigated for function (echocardiography, magnetic resonance investigation), morpho/histological appearance, graft rejection, and calcification at 3 months. Decellularization led to cell-free scaffolds with preserved extracellular matrices, including the basement membrane. TEVs were covered with ECs expressing typical endothelial markers. Neither dilatation, stenosis, reductions of cusp mobility nor a significant transvalvular gradient, were observed in the TEV group. Explanted valves exhibited normal morphology without signs of inflammation. An endothelial monolayer covered cusps and the valve sinus. In the CPV group, sporadic, macroscopic, calcified degeneration with mild AV insufficiency was noted. Histology revealed signs of rejection and incipient calcification of the tissue. Tissue-engineered AV based on decellularized valve allografts satisfy short-term requirements of the systemic circulation in sheep. Although results of long-term experiments are pending, the lack of degenerative traits thus far, makes these grafts a promising alternative for future aortic heart valve surgery.

  2. 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.

  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. 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.

  5. 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

    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......-based cardiac rehabilitation compared with no exercise training intervention, or treatment as usual, in adults following heart valve surgery. We considered programmes including exercise training with or without another intervention (such as a psycho-educational component). SEARCH METHODS: We searched...... handsearched Web of Science, bibliographies of systematic reviews and trial registers (ClinicalTrials.gov, Controlled-trials.com, and The World Health Organization International Clinical Trials Registry Platform). SELECTION CRITERIA: We included randomised clinical trials that investigated exercise...

  6. 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.

  7. Growth and remodeling play opposing roles during postnatal human heart valve development.

    Science.gov (United States)

    Oomen, Pim J A; Holland, Maria A; Bouten, Carlijn V C; Kuhl, Ellen; Loerakker, Sandra

    2018-01-19

    Tissue growth and remodeling are known to govern mechanical homeostasis in biological tissue, but their relative contributions to homeostasis remain unclear. Here, we use mechanical models, fueled by experimental findings, to demonstrate that growth and remodeling have different effects on heart valve stretch homeostasis during physiological postnatal development. Two developmental stages were considered: early-stage (from infant to adolescent) and late-stage (from adolescent to adult) development. Our models indicated that growth and remodeling play opposing roles in preserving tissue stretch and with time. During early-stage development, excessive tissue stretch was decreased by tissue growth and increased by remodeling. In contrast, during late-stage development tissue stretch was decreased by remodeling and increased by growth. Our findings contribute to an improved understanding of native heart valve adaptation throughout life, and are highly relevant for the development of tissue-engineered heart valves.

  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. Performance and morphology of decellularized pulmonary valves implanted in juvenile sheep.

    Science.gov (United States)

    Quinn, Rachael W; Hilbert, Stephen L; Bert, Arthur A; Drake, Bill W; Bustamante, Julie A; Fenton, Jason E; Moriarty, Sara J; Neighbors, Stacy L; Lofland, Gary K; Hopkins, Richard A

    2011-07-01

    Because of cryopreserved heart valve-mediated immune responses, decellularized allograft valves are an attractive option in children and young adults. The objective of this study was to investigate the performance and morphologic features of decellularized pulmonary valves implanted in the right ventricular outflow tract of juvenile sheep. Right ventricular outflow tract reconstructions in juvenile sheep (160±9 days) using cryopreserved pulmonary allografts (n=6), porcine aortic root bioprostheses (n=4), or detergent/enzyme-decellularized pulmonary allografts (n=8) were performed. Valve performance (echocardiography) and morphologic features (gross, radiographic, and histologic examination) were evaluated 20 weeks after implantation. Decellularization reduced DNA in valve cusps by 99.3%. Bioprosthetic valves had the largest peak and mean gradients versus decellularized valves (p=0.03; p<0.001) and cryopreserved valves (p=0.01; p=0.001), which were similar (p=0.45; p=0.40). Regurgitation was minimal and similar for all groups (p=0.16). No cusp calcification was observed in any valve type. Arterial wall calcification was present in cryopreserved and bioprosthetic grafts but not in decellularized valves. No autologous recellularization or inflammation occurred in bioprostheses, whereas cellularity progressively decreased in cryopreserved grafts. Autologous recellularization was present in decellularized arterial walls and variably extending into the cusps. Cryopreserved and decellularized graft hemodynamic performance was comparable. Autologous recellularization of the decellularized pulmonary arterial wall was consistently observed, with variable cusp recellularization. As demonstrated in this study, decellularized allograft valves have the potential for autologous recellularization. Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  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

    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. PMID:26139741

  11. 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.

  12. 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

  13. Optical monitoring during bioreactor conditioning of tissue-engineered heart valves.

    Science.gov (United States)

    Ziegelmueller, Johannes A; Zaenkert, Eva K; Schams, Rahmin; Lackermair, Stephan; Schmitz, Christoph; Reichart, Bruno; Sodian, Ralf

    2010-01-01

    Currently, one approach to tissue engineering has been to develop in vitro conditions to fabricate functional cardiovascular structures such as heart valves before final implantation. In vivo conditions are simulated using a bioreactor system that supplies cells with oxygen and culture media while providing mechanical stimulation to promote tissue maturation. In our experiment, we developed a novel combined optical monitoring and conditioning device. The entire system is made of acrylic glass and is completely transparent. The bioreactor is connected to an air-driven respirator pump, and the cell culture medium continuously circulates through a closed-loop system. By adjusting stroke volume, stroke rate, and inspiration/expiration time of the ventilator, the system allows various pulsatile flows and different levels of pressure. Our optical monitoring and conditioning device provides a sterile environment, mechanical stimulation, and optical monitoring for the in vitro maturation of a tissue-engineered heart valve. With the camera module attached, tissue-engineered valves can be observed during the entire in vitro phase. This setting helps to find the optimal dynamic conditions for tissue-engineered heart valves to mature by adjusting flow and pressure conditions to provide physiological opening and closing behavior of the heart valve construct.

  14. Twist1 promotes heart valve cell proliferation and extracellular matrix gene expression during development in vivo and is expressed in human diseased aortic valves

    Science.gov (United States)

    Chakraborty, Santanu; Wirrig, Elaine E.; Hinton, Robert B.; Merrill, Walter H.; Spicer, Douglas B.; Yutzey, Katherine E.

    2010-01-01

    During embryogenesis the heart valves develop from undifferentiated mesenchymal endocardial cushions (EC), and activated interstitial cells of adult diseased valves share characteristics of embryonic valve progenitors. Twist1, a class II basic-helix-loop-helix (bHLH) transcription factor, is expressed during early EC development and is downregulated later during valve remodeling. The requirements for Twist1 down-regulation in the remodeling valves and the consequences of prolonged Twist1 activity were examined in transgenic mice with persistent expression of Twist1 in developing and mature valves. Persistent Twist1 expression in the remodeling valves leads to increased valve cell proliferation, increased expression of Tbx20, and increased extracellular matrix (ECM) gene expression, characteristic of early valve progenitors. Among the ECM genes predominant in the EC, Col2a1 was identified as a direct transcriptional target of Twist1. Increased Twist1 expression also leads to dysregulation of fibrillar collagen and periostin expression, as well as enlarged hypercellular valve leaflets prior to birth. In human diseased aortic valves, increased Twist1 expression and cell proliferation are observed adjacent to nodules of calcification. Overall, these data implicate Twist1 as a critical regulator of valve development and suggest that Twist1 influences ECM production and cell proliferation during disease. PMID:20804746

  15. Fiber heart valve prosthesis: influence of the fabric construction parameters on the valve fatigue performances.

    Science.gov (United States)

    Vaesken, Antoine; Heim, Frederic; Chakfe, Nabil

    2014-12-01

    Transcatheter aortic valve replacement (TAVR) has become today a largely considered alternative technique to surgical valve replacement in patients who are not operable or patients with high risk for open chest surgery. However, the biological valve tissue used in the devices implanted clinically appears to be fragile material when folded for low diameter catheter insertion purpose and released in calcified environment with irregular geometry. Textile polyester material is characterized by outstanding folding and strength properties combined with proven biocompatibility. It could thereof be considered to replace biological valve leaflets in the TAVR procedure. The textile construction parameters must however be tuned to obtain a material compatible with the valve requested durability. In that context, one issue to be addressed is the friction effect that occurs between filaments and between yarns within a fabric under flexure loading. This phenomenon could be critical for the resistance of the material on the long term. The purpose of the present work is to assess the fatigue performances of textile valve prototypes made from different fabric constructions (monofilament, multifilament, calendered mutifilament) under accelerated cyclic loading. The goal is to identify, which construction is the best suited to long term fatigue stress. Results show that calendered multifilament and monofilament fabric constructions undergo strong ruptures already from 40 Mio cycles, while non calendered multifilament appears more durable. The rupture patterns observed point out that durability is directly related to the flexure stiffness level of the fibrous elements in the construction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. 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

  17. A new construction technique for tissue-engineered heart valves using the self-assembly method.

    Science.gov (United States)

    Tremblay, Catherine; Ruel, Jean; Bourget, Jean-Michel; Laterreur, Véronique; Vallières, Karine; Tondreau, Maxime Y; Lacroix, Dan; Germain, Lucie; Auger, François A

    2014-11-01

    Tissue engineering appears as a promising option to create new heart valve substitutes able to overcome the serious drawbacks encountered with mechanical substitutes or tissue valves. The objective of this article is to present the construction method of a new entirely biological stentless aortic valve using the self-assembly method and also a first assessment of its behavior in a bioreactor when exposed to a pulsatile flow. A thick tissue was created by stacking several fibroblast sheets produced with the self-assembly technique. Different sets of custom-made templates were designed to confer to the thick tissue a three-dimensional (3D) shape similar to that of a native aortic valve. The construction of the valve was divided in two sequential steps. The first step was the installation of the thick tissue in a flat preshaping template followed by a 4-week maturation period. The second step was the actual cylindrical 3D forming of the valve. The microscopic tissue structure was assessed using histological cross sections stained with Masson's Trichrome and Picrosirius Red. The thick tissue remained uniformly populated with cells throughout the construction steps and the dense extracellular matrix presented corrugated fibers of collagen. This first prototype of tissue-engineered heart valve was installed in a bioreactor to assess its capacity to sustain a light pulsatile flow at a frequency of 0.5 Hz. Under the light pulsed flow, it was observed that the leaflets opened and closed according to the flow variations. This study demonstrates that the self-assembly method is a viable option for the construction of complex 3D shapes, such as heart valves, with an entirely biological material.

  18. Prevention of device-related tissue damage during percutaneous deployment of tissue-engineered heart valves.

    Science.gov (United States)

    Stock, U A; Degenkolbe, I; Attmann, T; Schenke-Layland, K; Freitag, S; Lutter, G

    2006-06-01

    Endovascular application of pulmonary heart valves has been recently introduced clinically. A tissue-engineering approach was pursued to overcome the current limitations of bovine jugular vein valves (degeneration and limited longevity). However, deployment of the delicate tissue-engineered valves resulted in severe tissue damage. Therefore the objective of this study was to prevent tissue damage during the folding and deployment maneuver. Porcine pulmonary heart valves, small intestinal submucosa, and ovine carotid arteries were obtained from a slaughterhouse. After dissection and antimicrobial incubation, the valves were trimmed (removal of sinus and most of the muscular ring) to fit into the deployment catheter. The inside (in-stent group, n = 6) or outside (out-stent group, n = 6) of a nitinol stent was covered by an acellular small intestinal submucosa, and the valves were sutured into the stent. The valves were folded, tested for placement in the deployment catheter, and decellularized enzymatically. Myofibroblasts were obtained from carotid artery segments and seeded onto the scaffolds. The seeded constructs were placed in a dynamic bioreactor system and cultured for 16 consecutive days. After endothelial cell seeding, the constructs were folded, deployed, and processed for histology and surface electron microscopy. The valves opened and closed competently throughout the entire dynamic culture. Surface electron microscopy revealed an almost completely preserved tissue in the in-stent group. Stents covered with small intestinal submucosa on the outside, however, showed severe damage. This study demonstrates that small intestinal submucosa covering of the inside of a pulmonary valved stent can prevent stent strut-related tissue damage.

  19. Characterization of18F-Fluorodeoxyglucose Uptake Pattern in Noninfected Prosthetic Heart Valves.

    Science.gov (United States)

    Mathieu, Cédric; Mikaïl, Nidaa; Benali, Khadija; Iung, Bernard; Duval, Xavier; Nataf, Patrick; Jondeau, Guillaume; Hyafil, Fabien; Le Guludec, Dominique; Rouzet, François

    2017-03-01

    18 F-Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) has been recently acknowledged as a diagnostic tool for prosthetic valve endocarditis, but its specificity is limited by uptake on noninfected valves. The objective of this study was to outline the main features of FDG uptake on PET/CT in patients with noninfected prosthetic heart valve (PHV). Our institution's PET/CT database was reviewed to identify patients with PHV, excluding those suspected of infection or who had received antibiotic treatment. PET indication, valve location, and type (biological/mechanical) and time from implantation were collected for each patient. Images with and without attenuation correction were considered for interpretation. The pattern of FDG uptake (absent, homogeneous, or heterogeneous) was recorded. Fifty-four PHVs (51 patients) were identified, including 32 biological valves. Indications for PET were oncology (n=26), suspicion of prosthetic valve endocarditis subsequently excluded (n=17), and history of vasculitis (n=11). A periprosthetic FDG uptake was present in 47 (87%) and 30 (56%) PHVs with and without attenuation correction, respectively, and the pattern was homogeneous in all but 4 (7%) and 3 (6%) PHVs, respectively. On quantitative analysis, maximum standardized uptake values was greater in mechanical than in biological valves (4.0 [2.4-8.0] versus 3.3 [2.1-6.1]; P =0.01) and in patients with vasculitis than in those referred for other indications. The uptake intensity did not differ before and 3 months after valve replacement. Noninfected PHVs frequently display homogeneous FDG uptake, which remains steady over time. Caution is, therefore, needed when interpreting FDG PET/CT in suspected prosthetic valve endocarditis, with specific attention to uptake pattern. © 2017 American Heart Association, Inc.

  20. Heart valve prostheses: who protects our patients, and from what?

    Science.gov (United States)

    Beall, A C

    1977-01-01

    Phenomenal advances in the development of cardiac valve prostheses have taken place in less than two decades. However, the currently prevailing atmosphere of consumer protectionism in existence 20 years ago probably would have made such developments impossible. Recent passage of the Medical Device Amendments of 1976 (P.L. 94-295) will not only make future development extremely difficult, but also may force the field of cardiac valve replacement back into the era of the 1950s. Regulations implementing this legislation may be even more disastrous. It is time for someone to protect patients from their so-called protectors.

  1. 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.

  2. Biodegradable and biomimetic elastomeric scaffolds for tissue-engineered heart valves.

    Science.gov (United States)

    Xue, Yingfei; Sant, Vinayak; Phillippi, Julie; Sant, Shilpa

    2017-01-15

    Valvular heart diseases are the third leading cause of cardiovascular disease, resulting in more than 25,000 deaths annually in the United States. Heart valve tissue engineering (HVTE) has emerged as a putative treatment strategy such that the designed construct would ideally withstand native dynamic mechanical environment, guide regeneration of the diseased tissue and more importantly, have the ability to grow with the patient. These desired functions could be achieved by biomimetic design of tissue-engineered constructs that recapitulate in vivo heart valve microenvironment with biomimetic architecture, optimal mechanical properties and possess suitable biodegradability and biocompatibility. Synthetic biodegradable elastomers have gained interest in HVTE due to their excellent mechanical compliance, controllable chemical structure and tunable degradability. This review focuses on the state-of-art strategies to engineer biomimetic elastomeric scaffolds for HVTE. We first discuss the various types of biodegradable synthetic elastomers and their key properties. We then highlight tissue engineering approaches to recreate some of the features in the heart valve microenvironment such as anisotropic and hierarchical tri-layered architecture, mechanical anisotropy and biocompatibility. Heart valve tissue engineering (HVTE) is of special significance to overcome the drawbacks of current valve replacements. Although biodegradable synthetic elastomers have emerged as promising materials for HVTE, a mature HVTE construct made from synthetic elastomers for clinical use remains to be developed. Hence, this review summarized various types of biodegradable synthetic elastomers and their key properties. The major focus that distinguishes this review from the current literature is the thorough discussion on the key features of native valve microenvironments and various up-and-coming approaches to engineer synthetic elastomers to recreate these features such as anisotropic tri

  3. Valve Repair or Replacement

    Science.gov (United States)

    ... Replacement Menu Topics Topics FAQs Valve Repair or Replacement Heart valves play a key role in this ... leaflets with a tissue patch. What is valve replacement? Severe valve damage means the valve must be ...

  4. 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.

  5. 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

  6. Tissue-Engineered Fibrin-Based Heart Valve with Bio-Inspired Textile Reinforcement.

    Science.gov (United States)

    Moreira, Ricardo; Neusser, Christine; Kruse, Magnus; Mulderrig, Shane; Wolf, Frederic; Spillner, Jan; Schmitz-Rode, Thomas; Jockenhoevel, Stefan; Mela, Petra

    2016-08-01

    The mechanical properties of tissue-engineered heart valves still need to be improved to enable their implantation in the systemic circulation. The aim of this study is to develop a tissue-engineered valve for the aortic position - the BioTexValve - by exploiting a bio-inspired composite textile scaffold to confer native-like mechanical strength and anisotropy to the leaflets. This is achieved by multifilament fibers arranged similarly to the collagen bundles in the native aortic leaflet, fixed by a thin electrospun layer directly deposited on the pattern. The textile-based leaflets are positioned into a 3D mould where the components to form a fibrin gel containing human vascular smooth muscle cells are introduced. Upon fibrin polymerization, a complete valve is obtained. After 21 d of maturation by static and dynamic stimulation in a custom-made bioreactor, the valve shows excellent functionality under aortic pressure and flow conditions, as demonstrated by hydrodynamic tests performed according to ISO standards in a mock circulation system. The leaflets possess remarkable burst strength (1086 mmHg) while remaining pliable; pronounced extracellular matrix production is revealed by immunohistochemistry and biochemical assay. This study demonstrates the potential of bio-inspired textile-reinforcement for the fabrication of functional tissue-engineered heart valves for the aortic position. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Tissue-engineered fibrin-based heart valve with a tubular leaflet design.

    Science.gov (United States)

    Weber, Miriam; Heta, Eriona; Moreira, Ricardo; Gesche, Valentine N; Schermer, Thomas; Frese, Julia; Jockenhoevel, Stefan; Mela, Petra

    2014-04-01

    The general approach in heart valve tissue engineering is to mimic the shape of the native valve in the attempt to recreate the natural haemodynamics. In this article, we report the fabrication of the first tissue-engineered heart valve (TEHV) based on a tubular leaflet design, where the function of the leaflets of semilunar heart valves is performed by a simple tubular construct sutured along a circumferential line at the root and at three single points at the sinotubular junction. The tubular design is a recent development in pericardial (nonviable) bioprostheses, which has attracted interest because of the simplicity of the construction and the reliability of the implantation technique. Here we push the potential of the concept further from the fabrication and material point of view to realize the tube-in-tube valve: an autologous, living HV with remodelling and growing capability, physiological haemocompatibility, simple to construct and fast to implant. We developed two different fabrication/conditioning procedures and produced fibrin-based constructs embedding cells from the ovine umbilical cord artery according to the two different approaches. Tissue formation was confirmed by histology and immunohistology. The design of the tube-in-tube foresees the possibility of using a textile coscaffold (here demonstrated with a warp-knitted mesh) to achieve enhanced mechanical properties in vision of implantation in the aortic position. The tube-in-tube represents an attractive alternative to the conventional design of TEHVs aiming at reproducing the valvular geometry.

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

    African Journals Online (AJOL)

    Renal haemosiderosis is the anatomical indicator of intravascular 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 routine adult autopsy cases. Significant renal haemosiderosis was ...

  9. Renal Haemosiderosis in Patients with· Prosthetic Heart Valves

    African Journals Online (AJOL)

    1974-04-13

    Apr 13, 1974 ... showing renal siderosis was a 57-year-old White male who had mitral stenosis, trivial aortic stenosis and functional tricuspid incompetence. Cardiac symptoms had been pre- sent for 10 years. This same patient had large amounts of. Valve lesion. Mitral stenosis/incompetence. Aortic stenosis/incompetence.

  10. Renal Haemosiderosis in Patients with· Prosthetic Heart Valves

    African Journals Online (AJOL)

    1974-04-13

    Apr 13, 1974 ... 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 routine adult autopsy cases. Significant renal ...

  11. Clinical application of tissue engineered human heart valves using autologous progenitor cells.

    Science.gov (United States)

    Cebotari, Serghei; Lichtenberg, Artur; Tudorache, Igor; Hilfiker, Andres; Mertsching, Heike; Leyh, Rainer; Breymann, Thomas; Kallenbach, Klaus; Maniuc, Liviu; Batrinac, Aurel; Repin, Oleg; Maliga, Oxana; Ciubotaru, Anatol; Haverich, Axel

    2006-07-04

    Tissue engineering (TE) of heart valves reseeded with autologous cells has been successfully performed in vitro. Here, we report our first clinical implantation of pulmonary heart valves (PV) engineered with autologous endothelial progenitor cells (EPCs) and the results of 3.5 years of follow-up. Human PV allografts were decellularized (Trypsin/EDTA) and resulting scaffolds reseeded with peripheral mononuclear cells isolated from human blood. Positive stain for von Willebrand factor, CD31, and Flk-1 was observed in monolayers of cells cultivated and differentiated on the luminal surface of the scaffolds in a dynamic bioreactor system for up to 21 days, indicating endothelial nature. PV reseeded with autologous cells were implanted into 2 pediatric patients (age 13 and 11) with congenital PV failure. Postoperatively, a mild pulmonary regurgitation was documented in both children. Based on regular echocardiographic investigations, hemodynamic parameters and cardiac morphology changed in 3.5 years as follows: increase of the PV annulus diameter (18 to 22.5 mm and 22 to 26 mm, respectively), decrease of valve regurgitation (trivial/mild and trivial, respectively), decrease (16 to 9 mm Hg) or a increase (8 to 9.5 mm Hg) of mean transvalvular gradient, remained 26 mm or decreased (32 to 28 mm) right-ventricular end-diastolic diameter. The body surface area increased (1.07 to 1.42 m2 and 1.07 to 1.46 m2, respectively). No signs of valve degeneration were observed in both patients. TE of human heart valves using autologous EPC is a feasible and safe method for pulmonary valve replacement. TE valves have the potential to remodel and grow accordingly to the somatic growth of the child.

  12. Decellularization does not eliminate thrombogenicity and inflammatory stimulation in tissue-engineered porcine heart valves.

    Science.gov (United States)

    Kasimir, Marie-Theres; Rieder, Erwin; Seebacher, Gernot; Nigisch, Anneliese; Dekan, Barbara; Wolner, Ernst; Weigel, Guenter; Simon, Paul

    2006-03-01

    In tissue engineering of heart valves using decellularized xenogenic valves, it has been suggested that cell elimination would result in a biologically inert matrix. The aim of this in-vitro investigation was to evaluate different decellularization methods in regard to the completeness of cell removal, inflammatory response, and thrombocyte activation. Decellularized porcine Synergraft valves were compared with porcine pulmonary conduits decellularized with Triton X-100, sodium deoxycholate, Igepal CA-630 and ribonuclease. Completeness of decellularization was evaluated with staining for nuclei and alpha-Gal epitope. Decellularized heart valves with and without seeding with endothelial cells (ECs) were incubated with human platelet-rich plasma and stained for CD41 and PAC-1 to evaluate thrombocyte activation. Samples were processed for laser scanning microscopy (LSM) and scanning electron microscopy (SEM). Migration of human monocytic cells towards extracted valve proteins was tested. In contrast to the Synergraft, complete cell removal and elimination of the alpha-gal epitope was achieved with the new decellularization method. Numerous adherent and activated platelets were found on the decellularized matrix. This was inhibited by seeding with ECs. Even in completely cell-free valve tissue extracellular matrix proteins attracted human monocytic cells as in early inflammation, depending on whether porcine or human tissue was used. Important differences were found in the decellularization efficacy of treatment methods. However, even complete elimination of cells and their remnants did not result in a biologically inert matrix. The decellularized porcine heart valve matrix has the potential to attract inflammatory cells and to induce platelet activation. These findings suggest that it will be important to control the different inflammation-stimulating factors if porcine tissues are to be used successfully in tissue engineering.

  13. In vivo remodeling and structural characterization of fibrin-based tissue-engineered heart valves in the adult sheep model.

    Science.gov (United States)

    Flanagan, Thomas C; Sachweh, Jörg S; Frese, Julia; Schnöring, Heike; Gronloh, Nina; Koch, Sabine; Tolba, Rene H; Schmitz-Rode, Thomas; Jockenhoevel, Stefan

    2009-10-01

    Autologous fibrin-based tissue-engineered heart valves have demonstrated excellent potential as patient-derived valve replacements. The present pilot study aims to evaluate the structure and mechanical durability of fibrin-based heart valves after implantation in a large-animal model (sheep). Tissue-engineered heart valves were molded using a fibrin scaffold and autologous arterial-derived cells before 28 days of mechanical conditioning. Conditioned valves were subsequently implanted in the pulmonary trunk of the same animals from which the cells were harvested. After 3 months in vivo, explanted valve conduits (n = 4) had remained intact and exhibited native tissue consistency, although leaflets demonstrated insufficiency because of tissue contraction. Routine histology showed remarkable tissue development and cell distribution, along with functional blood vessel ingrowth. A confluent monolayer of endothelial cells was present on the valve surface, as evidenced by scanning electron microscopy and positive von Willebrand factor staining. Immunohistochemistry and extracellular matrix (ECM) assay demonstrated complete resorption of the fibrin scaffold and replacement with ECM proteins. Transmission electron microscopy revealed mature collagen formation and viable, active resident tissue cells. The preliminary findings of implanted fibrin-based tissue-engineered heart valves are encouraging, with excellent tissue remodeling and structural durability after 3 months in vivo. The results from this pilot study highlight the potential for construction of completely "autologous" customized tissue-engineered heart valves based on a patient-derived fibrin scaffold.

  14. 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.

  15. Valve Disease

    Science.gov (United States)

    ... phen and Redux, which were removed from the market after being linked to heart valve disease. An ... have a prosthetic valve made of synthetic material. Beta-blockers control your heart rate and lower your ...

  16. 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 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%–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 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...

  17. Management of anticoagulant therapy for patients with prosthetic heart valves or atrial fibrillation

    NARCIS (Netherlands)

    Vink, Roel; van den Brink, Renée B. A.; Levi, Marcel

    2004-01-01

    There is a wide array of recommendations for the management of anticoagulant therapy in patients with mechanical heart valves. Especially the optimal intensity of vitamin K antagonists (VKA) is a ongoing matter of debate. On the basis of several studies, recommendations for daily clinical practice

  18. 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.

    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.

  19. 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

  20. 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.

  1. 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

  2. 75 FR 3238 - Draft Guidance for Industry and Food and Drug Administration Staff; Heart Valves...

    Science.gov (United States)

    2010-01-20

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2009-D-0559... Approval (PMA) Applications.'' It does not create or confer any rights for or on any person and does not... a copy of the draft guidance may do so by using the Internet. To receive ``Heart Valves...

  3. Percutaneous management of coronary embolism with prosthetic heart valve thrombosis after Bentall's procedure

    Directory of Open Access Journals (Sweden)

    Nagendra Boopathy Senguttuvan

    2015-11-01

    Full Text Available We describe a young male who had undergone a Bentall's procedure seven years ago presenting with acute severe chest pain. He was diagnosed to have coronary embolism from prosthetic heart valve thrombosis. Multiple treatment strategies for the patient were available and we briefly discuss the merits of each of them. We also describe the encountered difficulties in the percutaneous revascularization procedure.

  4. 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

  5. Pathologic analysis of 19 heart valves with silver-coated sewing rings.

    Science.gov (United States)

    Butany, Jagdish; Leask, Richard L; Desai, Nimesh D; Jegatheeswaran, Anusha; Silversides, Candice; Scully, Hugh E; Feindel, Christopher

    2006-01-01

    The St. Jude Medical Silzone (Silzone) mechanical heart valve was voluntarily recalled (January 2000) due to an unusually high incidence of paravalvular leaks. We present the first series of human morphological data on the failure of these valves. Nineteen Silzone valves were evaluated from the 176 Silzone valves implanted in 147 patients at our institution between 1997 and 1999. Explanted prostheses were fixed in 10% formalin, photographed, and X-rayed. Histological sections were collected from the sewing cuff, accompanying tissues, and thrombus. For comparison, six age-matched SJM-standard valves were similarly analyzed. Nineteen Silzone valves from 16 patients (10 male, six female, 52.0 +/- 15.2 years) were examined. Significantly more mitral (15/95) prostheses were removed than aortic (4/81) despite the nearly equal number implanted (p = 0.027). Fifteen of the Silzone valves (13/16 patients) were explanted in the early postoperative period (within six months of implantation), although collection continued for eight years after our institution stopped implanting them. The common indications for surgical explantation were paravalvular leak (8/12) and clinically suspected infective endocarditis (IE) (four patients, five valves). IE was not confirmed by histology or culture in any valve. The sewing cuffs of many Silzone valves showed large regions of pannus, granulation tissue, and purulent exudate. Polymorphonuclear leukocytes were more common in the sewing cuff of Silzone valves; however, the cellular infiltrate was superficial when compared to SJM-standard valves. This is the largest morphologically analyzed series of Silzone explants. It demonstrates a consistent pattern of atypical tissue incorporation into the silver-coated sewing ring particularly in the mitral position. Clinical and morphologic features of IE (sterile) are seen in the early postimplant period. Prosthesis-related problems were almost wholly seen at the mitral site, in our group. Our current

  6. 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

    : For each surgical type and label size, the two commonly used THV sizes, a given THV “standard” vs. a size larger “oversized” were compared among patients undergoing aortic ViV within VIVID Registry. The degree of THV perimeter oversizing was calculated as: (THV nominal size – surgical valve true ID...... group received a larger THV (25.5± 1.4 mm vs. 23.3 ± 1.0 mm, pdegree of THV oversizing (31% ± 10.6 vs. 20% ± 9.5, p=vs. 1.37± 0.5cm2, p....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...

  7. 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.

  8. 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.

  9. Towards robot-assisted anchor deployment in beating-heart mitral valve surgery.

    Science.gov (United States)

    Cheng, Lingbo; Sharifi, Mojtaba; Tavakoli, Mahdi

    2018-03-24

    Beating-heart intracardiac surgery promises significant benefits for patients compared with cardiopulmonary bypass based procedures. However, the fast motions of the heart introduce serious challenges for surgeons. In this work, a new impedance-controlled master-slave telerobotic system is developed to help perform anchor deployment for mitral valve annuloplasty under the guidance of live ultrasound images of the heart. The proposed bilateral teleoperation system can both reflect the non-oscillatory portion of slave-heart tissue interaction force on the surgeon's hand as haptic feedback and implement rapid compensation for the beating heart's motion. The surgical task involves performing anchor deployment on a simulated moving heart tissue to evaluate the effectiveness of the proposed strategy for safely interacting with a moving organ. The results obtained show that the telerobotic system increases the success rate of anchor deployment by 100% and reduces the excess force application rate by 70% compared with manual attempts. Copyright © 2018 John Wiley & Sons, Ltd.

  10. 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.

  11. 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.

  12. Comparative assessment of hepatic Glisson's capsule and bovine pericardium in heart valve bioprostheses.

    Science.gov (United States)

    Kagramanov, I I; Kokshenev, I V; Dobrova, N B; Kastava, V T; Serov, R A; Zaets, S B

    1998-05-01

    The optimal material for heart valve bioprostheses remains disputable. This investigation was initiated to compare the properties of hepatic Glisson's capsule, clinical experience of which in cardiovascular surgery is minimal, with those of bovine pericardium. Hepatic Glisson's capsule was harvested from bull calves and used to create composite pulmonary arterial monocusp grafts and bioprostheses. Comparison of the strength and elastic properties of Glisson's capsule and bovine pericardium, as well as the hydrodynamic characteristics of valves made from these materials, was performed. Late results of operations using these materials were estimated echocardiographically. Although Glisson's capsule tissue is thinner than the bovine pericardium, its elasticity modulus is greater. However, the hydrodynamic characteristics of heart valves made from either tissue are similar. Moreover, valves made from Glisson's capsule have a lower systolic pressure gradient on the prosthesis and a higher effective orifice area. Composite pulmonary arterial xenopericardial grafts with a monocusp of Glisson's capsule were used in 30 patients during tetralogy of Fallot repair. Glisson's capsule was also used for tricuspid valve reconstruction and as a bioprosthesis in six patients with Ebstein's anomaly. At 1-2 years after surgery, the Glisson's capsule tissue remained thin and flexible, with no calcification. Although the hydrodynamic properties of hepatic Glisson's capsule and the bovine pericardium are similar, the capsule tissue is thinner and has a greater elasticity modulos. Thus, Glisson's capsule may be used for bioprosthesis construction both independently and in combination with bovine pericardium.

  13. 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

  14. 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

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

    DEFF Research Database (Denmark)

    Sibilitz, Kirstine Lærum; Berg, Selina Klikkenborg; Rasmussen, Trine Bernholdt

    2016-01-01

    -educational 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......Objective: The evidence for cardiac rehabilitation after valve surgery remains sparse. Current recommendations are therefore based on patients with ischaemic heart disease. The aim of this randomised clinical trial was to assess the effects of cardiac rehabilitation versus usual care after heart...

  16. 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

    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......, 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...

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

    Science.gov (United States)

    Sibilitz, Kirstine L; Berg, Selina K; Tang, Lars H; Risom, Signe S; Gluud, Christian; Lindschou, Jane; Kober, Lars; Hassager, Christian; Taylor, Rod S; Zwisler, Ann-Dorthe

    2016-03-21

    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. To assess the benefits and harms of exercise-based cardiac rehabilitation compared with no exercise training intervention, or treatment as usual, in adults following heart valve surgery. We considered programmes including exercise training with or without another intervention (such as a psycho-educational component). We searched: 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 handsearched Web of Science, bibliographies of systematic reviews and trial registers (ClinicalTrials.gov, Controlled-trials.com, and The World Health Organization International Clinical Trials Registry Platform). We included randomised clinical trials that investigated exercise-based interventions compared with no exercise intervention control. The trial participants comprised adults aged 18 years or older who had undergone heart valve surgery for heart valve disease (from any cause) and received either heart valve replacement, or heart valve repair. Two authors independently extracted data. We assessed the risk of systematic errors ('bias') by evaluation of bias risk domains. Clinical and statistical heterogeneity were assessed. Meta-analyses were undertaken using both fixed-effect and random-effects models. We used the GRADE approach to assess the quality of evidence. We sought to assess the risk of random errors with trial sequential analysis. We included two trials from 1987 and 2004 with a total 148 participants who have had heart valve surgery. Both trials had a high risk of bias.There was insufficient evidence

  18. Design and Testing of a Pulsatile Conditioning System for Dynamic Endothelialization of Polyphenol-Stabilized Tissue Engineered Heart Valves.

    Science.gov (United States)

    Sierad, Leslie Neil; Simionescu, Agneta; Albers, Christopher; Chen, Joseph; Maivelett, Jordan; Tedder, Mary Elizabeth; Liao, Jun; Simionescu, Dan T

    2010-06-01

    Heart valve tissue engineering requires biocompatible and hemocompatible scaffolds that undergo remodeling and repopulation, but that also withstand harsh mechanical forces immediately following implantation. We hypothesized that reversibly stabilized acellular porcine valves, seeded with endothelial cells and conditioned in pulsatile bioreactors would pave the way for next generations of tissue engineered heart valves (TEHVs). A novel valve conditioning system was first designed, manufactured and tested to adequately assess TEHVs. The bioreactor created proper closing and opening of valves and allowed for multiple mounting methods in sterile conditions. Porcine aortic heart valve roots were decellularized by chemical extractions and treated with penta-galloyl glucose (PGG) for stabilization. Properties of the novel scaffolds were evaluated by testing resistance to collagenase and elastase, biaxial mechanical analysis, and thermal denaturation profiles. Porcine aortic endothelial cells were seeded onto the leaflets and whole aortic roots were mounted within the dynamic pulsatile heart valve bioreactor system under physiologic pulmonary valve pressures and analyzed after 17 days for cell viability, morphology, and metabolic activity. Our tissue preparation methods effectively removed cells, including the potent α-Gal antigen, while leaving a well preserved extra-cellular matrix scaffold with adequate mechanical properties. PGG enhanced stabilization of extracellular matrix components but also showed the ability to be reversible. Engineered valve scaffolds encouraged attachment and survival of endothelial cells for extended periods and showed signs of widespread cell coverage after conditioning. Our novel approach shows promise toward development of sturdy and durable TEHVs capable of remodeling and cellular repopulation.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

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

    Science.gov (United States)

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

    2014-06-27

    Preclinical studies of tissue-engineered heart valves (TEHVs) showed retraction of the heart valve leaflets as major failure of function mechanism. This retraction is caused by both passive and active cell stress and passive matrix stress. Cell-mediated retraction induces leaflet shortening that may be counteracted by the hemodynamic loading of the leaflets during diastole. To get insight into this stress balance, the amount and duration of stress generation in engineered heart valve tissue and the stress imposed by physiological hemodynamic loading are quantified via an experimental and a computational approach, respectively. Stress generation by cells was measured using an earlier described in vitro model system, mimicking the culture process of TEHVs. The stress imposed by the blood pressure during diastole on a valve leaflet was determined using finite element modeling. Results show that for both pulmonary and systemic pressure, the stress imposed on the TEHV leaflets is comparable to the stress generated in the leaflets. As the stresses are of similar magnitude, it is likely that the imposed stress cannot counteract the generated stress, in particular when taking into account that hemodynamic loading is only imposed during diastole. This study provides a rational explanation for the retraction found in preclinical studies of TEHVs and represents an important step towards understanding the retraction process seen in TEHVs by a combined experimental and computational approach. © 2013 Published by Elsevier Ltd.

  4. Inner ventricular structures and valves of the heart in white rhinoceros (Ceratotherium simum).

    Science.gov (United States)

    Erdoğan, Serkan; Lima, Martin; Pérez, William

    2014-01-01

    In this study, we describe the internal structures of both ventricles and the valvular apparatus of the heart of the white rhino. In the right of the heart, three papillary muscles were found in septal and marginal walls and m. papillaris magnus was the biggest. There was only one m. papillaris parvus in the right ventricle. The right atrioventricular valve was tricuspid, and the parietal cusp was longest. In the left of the heart, two papillary muscles were found on the septal wall and the subauricular was the biggest. The left atrioventricular valve was bicuspid and the parietal cusp was longest. There were no nodules in the valves of the pulmonary trunk and aorta, and the semilunar valves had many fibrous folds and transparent parts. Within the cardiac skeleton there was a cartilago cordis which occupied a small part of the right fibrous trigone. While the right ventricle included only one septomarginal trabecula, there were many trabeculae in the left ventricle. In both ventricles, the endocardium was thin and the subendocardial network was visible, also their continuation with the septomarginal trabeculae. We also found many trabeculae carneae in the dorsal part of the ventricles.

  5. 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

  6. When should a mechanical tricuspid valve replacement be considered?

    Science.gov (United States)

    Said, Sameh M; Burkhart, Harold M; Schaff, Hartzell V; Johnson, Jonathan N; Connolly, Heidi M; Dearani, Joseph A

    2014-08-01

    Isolated mechanical tricuspid valve replacement (mTVR) is uncommon, early mortality is reported to be high, and little is known regarding the long-term outcome. We sought to evaluate the long-term outcome of mTVR. From 1980 to 2007, isolated mTVR was performed in 64 patients (33 men) at our institution; the median age was 45.5 years (6-71 years). There were 2192 tricuspid valve (TV) repairs and 137 isolated bioprosthetic TV replacements during the same time interval. Valve dysfunction was caused by congenital TV abnormality in 45 patients (70%), carcinoid heart disease in 13 (20%), traumatic TV regurgitation in 3 (5%), and other reason in 3 (5%). Twenty-three patients (36%) had at least 1 previous cardiac procedure (TV repair in 8 and bioprosthetic TV replacement in 7). Mechanical prostheses used included Starr-Edwards (before 1993) in 36 patients (56%) and bileaflet prostheses in 28 (44%). Concomitant procedures included atrial septal defect closure in 28 (44%), arrhythmia surgery in 11 (17%), and pulmonary valvectomy for carcinoid disease in 10 patients (16%). Early mortality occurred in 5 patients (7.8%). Early morbidity included a permanent pacemaker in 9 (14%) and reexploration for bleeding in 2 patients (3%). Mean follow-up was 6 years (maximum 22.4 years). Five- and 10-year survival was 65% and 58%, respectively. There was no valve-related mortality. Late morbidity included valve thrombosis in 5 patients (8%); 3 were managed nonoperatively and 2 underwent TV rereplacement. Isolated mTVR still leads to increased early mortality. A mechanical valve can be considered in select situations when anticoagulation is necessary and in the presence of good right ventricular function. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  7. A detailed fluid mechanics study of tilting disk mechanical heart valve closure and the implications to blood damage.

    Science.gov (United States)

    Manning, Keefe B; Herbertson, Luke H; Fontaine, Arnold A; Deutsch, Steven

    2008-08-01

    Hemolysis and thrombosis are among the most detrimental effects associated with mechanical heart valves. The strength and structure of the flows generated by the closure of mechanical heart valves can be correlated with the extent of blood damage. In this in vitro study, a tilting disk mechanical heart valve has been modified to measure the flow created within the valve housing during the closing phase. This is the first study to focus on the region just upstream of the mitral valve occluder during this part of the cardiac cycle, where cavitation is known to occur and blood damage is most severe. Closure of the tilting disk valve was studied in a "single shot" chamber driven by a pneumatic pump. Laser Doppler velocimetry was used to measure all three velocity components over a 30 ms period encompassing the initial valve impact and rebound. An acrylic window placed in the housing enabled us to make flow measurements as close as 200 microm away from the closed occluder. Velocity profiles reveal the development of an atrial vortex on the major orifice side of the valve shed off the tip of the leaflet. The vortex strength makes this region susceptible to cavitation. Mean and maximum axial velocities as high as 7 ms and 20 ms were recorded, respectively. At closure, peak wall shear rates of 80,000 s(-1) were calculated close to the valve tip. The region of the flow examined here has been identified as a likely location of hemolysis and thrombosis in tilting disk valves. The results of this first comprehensive study measuring the flow within the housing of a tilting disk valve may be helpful in minimizing the extent of blood damage through the combined efforts of experimental and computational fluid dynamics to improve mechanical heart valve designs.

  8. Transcatheter edge-to-edge mitral valve repair in heart failure.

    Science.gov (United States)

    Orban, Mathias; Orban, Martin; Braun, Daniel; Nabauer, Michael; Massberg, Steffen; Hausleiter, Jörg

    2017-06-01

    Heart failure and severe mitral regurgitation (MR) are mutually dependent. Secondary MR is a consequence of chronic heart failure in patients with severely depressed left ventricular ejection fraction (LV-EF) and LV dilatation. Severe MR in heart failure patients worsens prognosis and accelerates LV dilatation and decline in LV-EF. Interventional therapies have changed clinical practice for heart failure patients with secondary MR. In this review we summarize the available data of patients with chronic heart failure undergoing transcatheter edge-to-edge mitral valve repair (TMVR) with the MitraClip® system for severe secondary mitral regurgitation. TMVR could be a therapeutic option with a favorable long-term outcome even in patients with severely depressed LV-EF. Selection criteria predicting mortality in patients undergoing TMVR comprise clinical, laboratory and echocardiographic parameters and can help for clinical decision-making. Ongoing randomized trials will influence the use of interventional treatment of MR in these high-risk patients.

  9. 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.

  10. Human or animal homograft: could they have a future as a biological scaffold for engineered heart valves?

    Science.gov (United States)

    Dainese, L; Biglioli, P

    2010-06-01

    Tissue-engineered heart valves (TEHVs) promise to be the ideal heart valve replacement: they have the potential to grow and repair within the host, to minimise inflammatory and immunological responses and to limit thromboembolism. Viable cells included in TEHVs can theoretically adapt to a growing and changing environment exactly as a native biological structure. This could be extremely important in case of paediatric applications, where reoperations are frequently required to replace failed valve substitutes or to accommodate the growth of the patient. At present time the biological matrix from allogenic or xenogenic decellularized valves represents an appropriate valve scaffold in TEHVs, showing theoretically an ability to grow and repair within the host. Viable cells included in extracellular valve matrix can theoretically adapt to a growing and changing environment like the native biological structure. The aim of this paper is to present a review concerning the use of homograft and allograft valves as an ideal substrate for cardiac engineered tissue valves that represent an exciting possibility for in situ regeneration and repair of heart valves.

  11. Outcome of double vs. single valve replacement for rheumatic heart disease

    International Nuclear Information System (INIS)

    Akhtar, R.P.; Abid, A.R.

    2010-01-01

    To compare the follow-up results of double valve replacement (DVR) i.e. mitral valve replacement (MVR) and aortic valve replacement (AVR) vs. isolated MVR or AVR for rheumatic heart disease. Study Design: An interventional qausi-experimental study. Prospective follow-up of 493 patients with mechanical heart valves was carried out using clinical assessment, international normalized ratio and echocardiography. Patients were divided into three groups: group I having MVR, group II having AVR and group III having DVR. Survival, time and causes of mortality, and frequency of valve thrombosis, haemorrhage and cerebrovascular haemorrhage was noted in the three groups and described as proportions. Actuarial survival was analyzed by Kaplan-Meier method. There were 493 with 287 (58.3%) in group I, 87 (17.6%) in group II and 119 (24.1%) in group III. Total follow-up was 2429.2 patient (pt)-years. Of 77 (15.6%) deaths, 19 (3.8%) were in-hospital and 58 (11.8%) were late. In-hospital mortality was highest 4 (4.6%) in group II followed by 5 (4.2%) group III and 10 (3.5%) group I. Late deaths were 39 (13.4%) in group I, 9 (10.2%) in group II and 10 (8.3%) in group III. The total actuarial survival was 84.4% with survival of 83%, 85.1%, 87.4% in groups I, II and III respectively. On follow-up valve thrombosis occurred in 12 (0.49%/pt-years) patients; 9 (0.67%/pt-years) group I, 1 (0.22%/pt-years) in group II and 2 (0.31%/pt-years) in group III. Severe haemorrhage occurred in 19 (0.78%/pt-years); 14 in (1.04%/pt-years) in group I, 3 (0.66%/pt-years) group II and 2 (0.31%/pt-years) in group III. Cerebrovascular accidents occurred in 34 (1.3%/pt-years); 26 (1.95%/pt-years) in group I and 4 in groups II (0.89%/pt-years) and III (0.62%/pt-years) each. In patients with rheumatic heart disease having combined mitral and aortic valve disease DVR should be performed whenever indicated as it has similar in-hospital mortality and better late survival as compared to isolated aortic or mitral

  12. Non-destructive assessment of 62 Dutch Björk-Shiley convexo-concave heart valves

    NARCIS (Netherlands)

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

    1997-01-01

    Non-destructive assessment of 62 Björk-Shiley convexo-concave heart valves in view of the risk of fracture and possible detection of defects by means of X-ray or acoustics. Scanning electron microscopy and stereomicroscopy of an unselected sample of valves, representing approximately 70% of the

  13. Cells, scaffolds and bioreactors for tissue-engineered heart valves: a journey from basic concepts to contemporary developmental innovations.

    Science.gov (United States)

    Gandaglia, Alessandro; Bagno, Andrea; Naso, Filippo; Spina, Michele; Gerosa, Gino

    2011-04-01

    The development of viable and functional tissue-engineered heart valves (TEHVs) is a challenge that, for almost two decades, the scientific community has been committed to face to create life-lasting prosthetic devices for treating heart valve diseases. One of the main drawbacks of tissue-based commercial substitutes, xenografts and homografts, is their lack of viability, and hence failure to grow, repair, and remodel. In adults, the average bioprostheses life span is around 13 years, followed by structural valve degeneration, such as calcification; in pediatric, mechanical valves are commonly used instead of biological substitutes, as in young patients, the mobilization of calcium, due to bone remodeling, accelerates the calcification process. Moreover, neither mechanical nor bioprostheses are able to follow children's body growth. Cell seeding and repopulation of acellular heart valve scaffolds, biological and polymeric, appears as a promising way to create a living valve. Biomechanical stimuli have significant impact on cell behavior including in vitro differentiation, and physiological hemodynamic conditioning has been found to promote new tissue development. These concepts have led scientists to design bioreactors to mimic the in vivo environment of heart valves. Many different types of somatic and stem cells have been tested for colonizing both the surface and the core of the valve matrix but controversial results have been achieved so far. Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

  14. Rapid manufacturing techniques for the tissue engineering of human heart valves.

    Science.gov (United States)

    Lueders, Cora; Jastram, Ben; Hetzer, Roland; Schwandt, Hartmut

    2014-10-01

    Three-dimensional (3D) printing technologies have reached a level of quality that justifies considering rapid manufacturing for medical applications. Herein, we introduce a new approach using 3D printing to simplify and improve the fabrication of human heart valve scaffolds by tissue engineering (TE). Custom-made human heart valve scaffolds are to be fabricated on a selective laser-sintering 3D printer for subsequent seeding with vascular cells from human umbilical cords. The scaffolds will be produced from resorbable polymers that must feature a number of specific properties: the structure, i.e. particle granularity and shape, and thermic properties must be feasible for the printing process. They must be suitable for the cell-seeding process and at the same time should be resorbable. They must be applicable for implementation in the human body and flexible enough to support the full functionality of the valve. The research focuses mainly on the search for a suitable scaffold material that allows the implementation of both the printing process to produce the scaffolds and the cell-seeding process, while meeting all of the above requirements. Computer tomographic data from patients were transformed into a 3D data model suitable for the 3D printer. Our current activities involve various aspects of the printing process, material research and the implementation of the cell-seeding process. Different resorbable polymeric materials have been examined and used to fabricate heart valve scaffolds by rapid manufacturing. Human vascular cells attached to the scaffold surface should migrate additionally into the inner structure of the polymeric samples. The ultimate intention of our approach is to establish a heart valve fabrication process based on 3D rapid manufacturing and TE. Based on the computer tomographic data of a patient, a custom-made scaffold for a valve will be produced on a 3D printer and populated preferably by autologous cells. The long-term goal is to support

  15. Trans-apical versus surgical implantation of autologous ovine tissue-engineered heart valves.

    Science.gov (United States)

    Dijkman, Petra E; Driessen-Mol, Anita; de Heer, Linda M; Kluin, Jolanda; van Herwerden, Lex A; Odermatt, Berhard; Baaijens, Frank P T; Hoerstrup, Simon P

    2012-09-01

    Living tissue-engineered heart valves (TEHVs) based on rapidly degrading scaffolds and autologous cells might overcome the limitations of today's valve substitutes. Following minimally invasive trans-apical implantation into an ovine model, TEHVs showed adequate in-vivo functionality, but a thickening of the leaflets was observed. In order to evaluate the impact of the substantial tissue deformations of TEHVs associated with the crimping procedure during minimally invasive delivery, trans-apical and conventional implantation technologies were compared in an ovine model. Trileaflet heart valves (n=11) based on PGA/P4HB-scaffolds, integrated into self-expandable stents, were engineered from autologous ovine vascular-derived cells. After in-vitro culture, the TEHVs were either implanted surgically (n=5), replacing the native pulmonary valve, or delivered trans-apically (n=6) into the orthotopic pulmonary valve position. In-vivo functionality was assessed by echocardiography and by angiography for up to eight weeks. The tissue compositions of the explanted TEHVs and corresponding control valves were analyzed. TEHV implantations were successful in all cases. Independent of the implantation method, the explants demonstrated a comparable layered tissue formation with thickening and deposited fibrous layers. Active remodeling of these layers was evident in the explants, as indicated by vascularization of the walls, invasion of the host cells, and the formation of a luminal endothelial layer on the TEHV leaflets. This direct comparison of trans-apical and conventional surgical implantation techniques showed that crimping had no adverse effect on the integrity or functional outcome of TEHVs. This suggests that a thickening of TEHVs in vivo is neither caused by nor enhanced by the crimping procedure, but represents a functional tissue remodeling process.

  16. Diagnostic evaluation and treatment strategy in patients with suspected prosthetic heart valve dysfunction: The incremental value of MDCT

    NARCIS (Netherlands)

    Suchá, Dominika; Symersky, Petr; van den Brink, Renee B. A.; Tanis, Wilco; Laufer, Eduard M.; Meijs, Matthijs F. L.; Habets, Jesse; de Mol, Bas A. J. M.; Mali, Willem P. Th M.; Chamuleau, Steven A. J.; van Herwerden, Lex A.; Budde, Ricardo P. J.

    2016-01-01

    In patients with suspected prosthetic heart valve (PHV) dysfunction, routine evaluation echocardiography and fluoroscopy may provide unsatisfactory results for identifying the cause of dysfunction. This study assessed the value of MDCT as a routine, complementary imaging modality in suspected

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

    NARCIS (Netherlands)

    Suchá, Dominika; Chamuleau, Steven A. J.; Symersky, Petr; Meijs, Matthijs F. L.; van den Brink, Renee B. A.; de Mol, Bas A. J. M.; Mali, Willem P. Th M.; Habets, Jesse; van Herwerden, Lex A.; Budde, Ricardo P. J.

    2016-01-01

    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

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

    NARCIS (Netherlands)

    Suchá, Dominika; Chamuleau, Steven A J|info:eu-repo/dai/nl/236454161; Symersky, Petr; Meijs, Matthijs F L; van den Brink, Renee B A; de Mol, Bas A J M; Mali, Willem P Th M|info:eu-repo/dai/nl/071107533; Habets, Jesse|info:eu-repo/dai/nl/343392445; van Herwerden, Lex A; Budde, Ricardo P J|info:eu-repo/dai/nl/275169472

    OBJECTIVES: 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

  19. Measurements of the effects of decellularization on viscoelastic properties of tissues in ovine, baboon, and human heart valves.

    Science.gov (United States)

    Jiao, Tong; Clifton, Rodney J; Converse, Gabriel L; Hopkins, Richard A

    2012-02-01

    In the development of tissue-engineered heart valves based on allograft decellularized extracellular matrix scaffolds, the material properties of the implant should be ideally comparable to the native semilunar valves. This investigation of the viscoelastic properties of the three functional aortic/pulmonary valve tissues (leaflets, sinus wall, and great vessel wall) was undertaken to establish normative values for fresh samples of human valves and to compare these properties after various steps in creating scaffolds for subsequent bioreactor-based seeding protocols. Torsional wave methods were used to measure the viscoelastic properties. Since preclinical surgical implant validation studies require relevant animal models, the tests reported here also include results for three pairs of both ovine and baboon aortic and pulmonary valves. For human aortic valves, four cryopreserved valves were compared with four decellularized scaffolds. Because of organ and heart valve transplant scarcity for pulmonary valves, only three cryopreserved and two decellularized pulmonary valves were tested. Leaflets are relatively soft. Loss angles are similar for all tissue samples. Regardless of species, the decellularization process used in this study has little effect on viscoelastic properties.

  20. 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.

  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 disease requiring myocardial revascularization [HR = 2.79 (1.26-6.20), P = 0.012], and aortic valve stenosis [HR = 2.6 (1.15-5.85), P = 0.021]. Significant predictive factors from univariate analyses were double-valve replacement combined with tricuspid annuloplasty [HR = 2.21 (1.11-4.39), P = 0.003] and preoperatively impaired ejection fraction [HR = 1.98 (1.04-3.92), P = 0.044]. However, successful mitral valve repair showed a protective effect [HR = 0.32 (0.10-0.98), P = 0.046]. Additionally, in instances where tricuspid regurgitation required the need for concomitant tricuspid valve repair, mortality predictor scores such as Euroscore 2 could be shortened to a simple Euroscore-tricuspid comprised of only 7 inputs. The 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. Age-dependent changes of stress and strain in the human heart valve and their relation with collagen remodeling.

    Science.gov (United States)

    Oomen, P J A; Loerakker, S; van Geemen, D; Neggers, J; Goumans, M-J T H; van den Bogaerdt, A J; Bogers, A J J C; Bouten, C V C; Baaijens, F P T

    2016-01-01

    In order to create tissue-engineered heart valves with long-term functionality, it is essential to fully understand collagen remodeling during neo-tissue formation. Collagen remodeling is thought to maintain mechanical tissue homeostasis. Yet, the driving factor of collagen remodeling remains unidentified. In this study, we determined the collagen architecture and the geometric and mechanical properties of human native semilunar heart valves of fetal to adult age using confocal microscopy, micro-indentation and inverse finite element analysis. The outcomes were used to predict age-dependent changes in stress and stretch in the heart valves via finite element modeling. The results indicated that the circumferential stresses are different between the aortic and pulmonary valve, and, moreover, that the stress increases considerably over time in the aortic valve. Strikingly, relatively small differences were found in stretch with time and between the aortic and pulmonary valve, particularly in the circumferential direction, which is the main determinant of the collagen fiber stretch. Therefore, we suggest that collagen remodeling in the human heart valve maintains a stretch-driven homeostasis. Next to these novel insights, the unique human data set created in this study provides valuable input for the development of numerical models of collagen remodeling and optimization of tissue engineering. Annually, over 280,000 heart valve replacements are performed worldwide. Tissue engineering has the potential to provide valvular disease patients with living valve substitutes that can last a lifetime. Valve functionality is mainly determined by the collagen architecture. Hence, understanding collagen remodeling is crucial for creating tissue-engineered valves with long-term functionality. In this study, we determined the structural and material properties of human native heart valves of fetal to adult age to gain insight into the mechanical stimuli responsible for collagen

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

    International Nuclear Information System (INIS)

    Zhao Shihua; Lu Minjie; Zhang Yan; Jiang Shiliang; Liu Yuqing; Zhang Puhong

    2006-01-01

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

  4. 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 (preport 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/

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

    International Nuclear Information System (INIS)

    Lamas, Gloria I.; Kairiyama, Eulogia; Navia, Jose

    2000-01-01

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

  6. 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.

  7. Surgical treatment of tricuspid regurgitation after mitral valve surgery: a retrospective study in China

    Science.gov (United States)

    2012-01-01

    Background Functional tricuspid regurgitation (TR) occurs in patients with rheumatic mitral valve disease even after mitral valve surgery. The aim of this study was to analyze surgical results of TR after previous successful mitral valve surgery. Methods From September 1996 to September 2008, 45 patients with TR after previous mitral valve replacement underwent second operation for TR. In those, 43 patients (95.6%) had right heart failure symptoms (edema of lower extremities, ascites, hepatic congestion, etc.) and 40 patients (88.9%) had atrial fibrillation. Twenty-six patients (57.8%) were in New York Heart Association (NYHA) functional class III, and 19 (42.2%) in class IV. Previous operations included: 41 for mechanical mitral valve replacement (91.1%), 4 for bioprosthetic mitral valve replacement (8.9%), and 7 for tricuspid annuloplasty (15.6%). Results The tricuspid valves were repaired with Kay's (7 cases, 15.6%) or De Vega technique (4 cases, 8.9%). Tricuspid valve replacement was performed in 34 cases (75.6%). One patient (2.2%) died. Postoperative low cardiac output (LCO) occurred in 5 patients and treated successfully. Postoperative echocardiography showed obvious reduction of right atrium and ventricle. The anterioposterior diameter of the right ventricle decreased to 25.5 ± 7.1 mm from 33.7 ± 6.2 mm preoperatively (P valve replacement in rheumatic heart disease is a serious clinical problem. If it occurs or progresses late after mitral valve surgery, tricuspid valve annuloplasty or replacement may be performed with satisfactory results. Due to the serious consequence of untreated TR, aggressive treatment of existing TR during mitral valve surgery is recommended. PMID:22490269

  8. Surgical treatment of tricuspid regurgitation after mitral valve surgery: a retrospective study in China

    Directory of Open Access Journals (Sweden)

    Li Zong-Xiao

    2012-04-01

    Full Text Available Abstract Background Functional tricuspid regurgitation (TR occurs in patients with rheumatic mitral valve disease even after mitral valve surgery. The aim of this study was to analyze surgical results of TR after previous successful mitral valve surgery. Methods From September 1996 to September 2008, 45 patients with TR after previous mitral valve replacement underwent second operation for TR. In those, 43 patients (95.6% had right heart failure symptoms (edema of lower extremities, ascites, hepatic congestion, etc. and 40 patients (88.9% had atrial fibrillation. Twenty-six patients (57.8% were in New York Heart Association (NYHA functional class III, and 19 (42.2% in class IV. Previous operations included: 41 for mechanical mitral valve replacement (91.1%, 4 for bioprosthetic mitral valve replacement (8.9%, and 7 for tricuspid annuloplasty (15.6%. Results The tricuspid valves were repaired with Kay's (7 cases, 15.6% or De Vega technique (4 cases, 8.9%. Tricuspid valve replacement was performed in 34 cases (75.6%. One patient (2.2% died. Postoperative low cardiac output (LCO occurred in 5 patients and treated successfully. Postoperative echocardiography showed obvious reduction of right atrium and ventricle. The anterioposterior diameter of the right ventricle decreased to 25.5 ± 7.1 mm from 33.7 ± 6.2 mm preoperatively (P Conclusion TR after mitral valve replacement in rheumatic heart disease is a serious clinical problem. If it occurs or progresses late after mitral valve surgery, tricuspid valve annuloplasty or replacement may be performed with satisfactory results. Due to the serious consequence of untreated TR, aggressive treatment of existing TR during mitral valve surgery is recommended.

  9. 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

  10. 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 biological heart valve prostheses.

  11. 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.

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

    International Nuclear Information System (INIS)

    Khalil Ullah; Badsha, S.; Khan, A.; Kiani, M.R.; Ahmed, S.A.

    2002-01-01

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

  13. Supra-annular structure assessment for self-expanding transcatheter heart valve size selection in patients with bicuspid aortic valve.

    Science.gov (United States)

    Liu, Xianbao; He, Yuxin; Zhu, Qifeng; Gao, Feng; He, Wei; Yu, Lei; Zhou, Qijing; Kong, Minjian; Wang, Jian'an

    2018-04-01

    To explore assessment of supra-annular structure for self-expanding transcatheter heart valve (THV) size selection in patients with bicuspid aortic stenosis (AS). Annulus-based device selection from CT measurement is the standard sizing strategy for tricuspid aortic valve before transcatheter aortic valve replacement (TAVR). Because of supra-annular deformity, device selection for bicuspid AS has not been systemically studied. Twelve patients with bicuspid AS who underwent TAVR with self-expanding THVs were included in this study. To assess supra-annular structure, sequential balloon aortic valvuloplasty was performed in every 2 mm increments until waist sign occurred with less than mild regurgitation. Procedural results and 30 day follow-up outcomes were analyzed. Seven patients (58.3%) with 18 mm; three patients (25%) with sequential 18 mm, 20 mm; and only two patients (16.7%) with sequential 18 mm, 20 mm, and 22 mm balloon sizing were performed, respectively. According to the results of supra-annular assessment, a smaller device size (91.7%) was selected in all but one patient compared with annulus based sizing strategy, and the outcomes were satisfactory with 100% procedural success. No mortality and 1 minor stroke were observed at 30 d follow-up. The percentage of NYHA III/IV decreased from 83.3% (9/12) to 16.7% (2/12). No new permanent pacemaker implantation and no moderate or severe paravalvular leakage were found. A supra-annular structure based sizing strategy is feasible for TAVR in patients with bicuspid AS. © 2018 The Authors Catheterization and Cardiovascular Interventions Published by Wiley Periodicals, Inc.

  14. 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.

  15. 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.

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

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    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. 

  17. 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

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

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    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.

  19. Variation in tissue outcome of ovine and human engineered heart valve constructs: relevance for tissue engineering.

    Science.gov (United States)

    van Geemen, Daphne; Driessen-Mol, Anita; Grootzwagers, Leonie G M; Soekhradj-Soechit, R Sarita; Riem Vis, Paul W; Baaijens, Frank P T; Bouten, Carlijn V C

    2012-01-01

    Clinical application of tissue engineered heart valves requires precise control of the tissue culture process to predict tissue composition and mechanical properties prior to implantation, and to understand the variation in tissue outcome. To this end we investigated cellular phenotype and tissue properties of ovine (n = 8) and human (n = 7) tissue engineered heart valve constructs to quantify variations in tissue outcome within species, study the differences between species and determine possible indicators of tissue outcome. Tissue constructs consisted of polyglycolic acid/poly-4-hydroxybutyrate scaffolds, seeded with myofibroblasts obtained from the jugular vein (sheep) or the saphenous vein (from humans undergoing cardiac surgery) and cultured under static conditions. Prior to seeding, protein expression of α-smooth muscle actin, vimentin, nonmuscle myosin heavy chain and heat shock protein 47 were determined to identify differences at an early stage of the tissue engineering process. After 4 weeks of culture, tissue composition and mechanical properties were quantified as indicators of tissue outcome. After 4 weeks of tissue culture, tissue properties of all ovine constructs were comparable, while there was a larger variation in the properties of the human constructs, especially the elastic modulus and collagen content. In addition, ovine constructs differed in composition from the human constructs. An increased number of α-smooth muscle actin-positive cells before seeding was correlated with the collagen content in the engineered heart valve constructs. Moreover, tissue stiffness increased with increasing collagen content. The results suggest that the culture process of ovine tissues can be controlled, whereas the mechanical properties, and hence functionality, of tissues originating from human material are more difficult to control. On-line evaluation of tissue properties during culture or more early cellular markers to predict the properties of autologous

  20. Clinical outcomes of tricuspid valve repair accompanying left-sided heart disease

    OpenAIRE

    Azarnoush, Kasra; Nadeemy, Ahmad S; Pereira, Bruno; Leesar, Massoud A; Lambert, Céline; Azhari, Alaa; Eljezi, Vedat; Dauphin, Nicolas; Geoffroy, Etienne; Camilleri, Lionel

    2017-01-01

    AIM 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. METHODS 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. RESULTS Tricuspid regurgitation etiology was functional in 154 cases (86%), organic in 16 cases (9%),...

  1. 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.

  2. Experimental Assessment of Flow Fields Associated with Heart Valve Prostheses Using Particle Image Velocimetry (PIV): Recommendations for Best Practices.

    Science.gov (United States)

    Raghav, Vrishank; Sastry, Sudeep; Saikrishnan, Neelakantan

    2018-03-12

    Experimental flow field characterization is a critical component of the assessment of the hemolytic and thrombogenic potential of heart valve substitutes, thus it is important to identify best practices for these experimental techniques. This paper presents a brief review of commonly used flow assessment techniques such as Particle image velocimetry (PIV), Laser doppler velocimetry, and Phase contrast magnetic resonance imaging and a comparison of these methodologies. In particular, recommendations for setting up planar PIV experiments such as recommended imaging instrumentation, acquisition and data processing are discussed in the context of heart valve flows. Multiple metrics such as residence time, local velocity and shear stress that have been identified in the literature as being relevant to hemolysis and thrombosis in heart valves are discussed. Additionally, a framework for uncertainty analysis and data reporting for PIV studies of heart valves is presented in this paper. It is anticipated that this paper will provide useful information for heart valve device manufacturers and researchers to assess heart valve flow fields for the potential for hemolysis and thrombosis.

  3. Valve-sparing root and ascending aorta replacement after heart transplantation.

    Science.gov (United States)

    Elhenawy, Abdelsalam M; Feindel, Christopher M; Ross, Heather; Butany, Jagdish; Yau, Terrence M

    2012-12-01

    A 45-year-old female underwent heart transplantation 17 years ago, with a heart from a 15-year-old donor. Recently, she had developed an aneurysm of the donor aortic root and ascending aorta, with severe aortic insufficiency. Two surgical options were considered; retransplantation versus replacement of the aortic root and ascending aorta. A valve-sparing replacement of the aortic root and ascending aortic aneurysm was performed. The donor aorta showed pathologic changes typical of Marfan syndrome. Nineteen months postoperatively, the patient remains in functional class I, with trivial aortic insufficiency. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  4. 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.

  5. 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.

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

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    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.

  7. Progression of Tricuspid Regurgitation after Mitral Valve Replacement for Rheumatic Heart Disease.

    Science.gov (United States)

    Q Tri, Ho H; Vinh, Pham N

    2017-05-01

    Progression of tricuspid regurgitation (TR) may occur after mitral valve replacement (MVR). The study aim was to define the independent predictors for new severe TR after MVR to treat rheumatic heart disease. A total of 413 patients (177 men, 236 women; mean age 40.9 ± 9.2 years) with rheumatic heart disease undergoing MVR without concomitant tricuspid valve repair at the authors' institute between 1995 and 2005, who did not have preoperative severe TR, were followed for at least one year postoperatively. Survival without severe TR was estimated using the Kaplan-Meier method. Independent predictors for new severe TR were identified using multiple Cox regression analysis. During a median follow up of 13 years there were two late deaths, and 46 patients (11.1%) had new severe TR. Survival without severe TR was 88.0 ± 1.7% at 10 years. Independent predictors for new severe TR were preoperative moderate TR (HR 2.401; p = 0.008) and atrial fibrillation (AF) (HR 2.119; p = 0.018). At the most recent follow up, furosemide was used in 23.9% patients with and 7.3% patients without new severe TR (p = 0.001). Patients with new severe TR had larger right ventricles and higher pulmonary artery pressures on echocardiography. Among patients with rheumatic heart disease undergoing MVR without concomitant tricuspid valve repair, independent predictors for new severe TR were preoperative moderate TR and AF. New severe TR was associated with increased furosemide use.

  8. 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.

  9. Degradable Chitosan-Collagen Composites Seeded with Cells as Tissue Engineered Heart Valves.

    Science.gov (United States)

    Fu, Jian-Hua; Zhao, Man; Lin, Yan-Rong; Tian, Xu-Dong; Wang, Ya-Dong; Wang, Zhen-Xing; Wang, Le-Xin

    2017-01-01

    Degradable collagen-chitosan composite materials have been used to fabricate tissue engineered heart valves. The aims of this study were to demonstrate that the collagen-chitosan composite scaffolds are cytocompatible, and endothelial cells can be differentiated from bone marrow mesenchymal stem cells (BMSCs) when seeded onto the scaffolds. The adhesion and biological activities of the seeded cells were also investigated. Collagen-chitosan composite material was used as the cell matrix, and smooth muscle cells, fibroblasts and BMSCs were used as seed cells. After four weeks of in vitro culture, the smooth muscle cells, fibroblasts, and BMSCs were sequentially seeded into the collagen-chitosan composite material. After four weeks in culture, the cellular density and activity were assessed on segments of the tissue engineered heart valve scaffolds to determine the cell viability and proliferation in the collagen-chitosan composite material. The tissue engineered heart valves stained positively for both smooth muscle actin and endothelial cell factor VIII, suggesting that the seeded cells were in fact smooth muscle cells, fibroblasts, and endothelial cells. The 6-ketone prostaglandin content, as measured by radioimmunoassay, of the collagen-chitosan cell culture fluid was higher than that of the serum-free medium (P biological activity after being cultured in vitro and seeded into the collagen-chitosan composite material. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  10. 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

  11. Trombose de prótese biológica mitral: importância do ecocardiograma transesofágico no diagnóstico e acompanhamento pós-tratamento Bioprosthetic mitral valve thrombosis: importance of transesophageal echocardiography in the diagnosis and follow-up after treatment

    Directory of Open Access Journals (Sweden)

    Adelino Parro Jr

    2004-04-01

    Full Text Available OBJETIVO: Descrever os achados clínicos e ecocardiográficos de trombose em prótese biológica mitral e o valor do ecocardiograma transesofágico (ETE no diagnóstico e monitoração da lise do trombo. MÉTODOS: Foram estudados ao ETE 111 pacientes com prótese biológica mitral, e incluídos 4 de 7 com suspeita de trombo nestas próteses (idade média = 60,2±10,2 anos; 2 homens. O diagnóstico pôde ser confirmado pela realização seriada do ETE e pela evolução clínica. Investigaram-se os aspectos morfológicos dos folhetos da prótese, e presença e característica das massas ecogênicas anexas. Foram obtidos o gradiente médio pela prótese e a área valvar. RESULTADOS: O diagnóstico de trombo em prótese biológica mitral foi realizado 48,7±55,2 meses após a cirurgia. Dois pacientes apresentaram acidente vascular encefálico isquêmico no pós-operatório imediato. O gradiente médio global estava elevado (11,4±3 mmHg e a área valvar reduzida (1,24±0,3cm². Ao ETE, em todos foram evidenciadas massas ecogênicas em face ventricular esquerda da prótese biológica mitral, sugestivas de trombo. No ETE seriado (136±233 dias, houve desaparecimento do trombo em dois casos e redução do trombo nos outros dois, após tratamento. O gradiente médio reduziu para 6,2±3 mmHg (p=0,004; IC 95%, e a área valvar aumentou para 2,07±0,4 (p=ns. CONCLUSÃO: O ETE mostrou-se útil na detecção de trombo em prótese biológica mitral e eficaz na monitoração do tratamento, em todos casos.OBJECTIVE: To report the clinical and echocardiographic findings of bioprosthetic mitral valve thrombosis and the value of transesophageal echocardiography (TEE in its diagnosis and monitoring of thrombolysis. METHODS: One hundred and eleven patients with mitral bioprostheses underwent TEE, and 4 out of 7 suspected of having a thrombus on these prostheses were included in the study (mean age = 60.2±10.2 years; 2 men. The diagnosis was confirmed with serial

  12. 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.

  13. 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.

  14. Endothelial progenitor cells as a sole source for ex vivo seeding of tissue-engineered heart valves.

    Science.gov (United States)

    Sales, Virna L; Mettler, Bret A; Engelmayr, George C; Aikawa, Elena; Bischoff, Joyce; Martin, David P; Exarhopoulos, Alexis; Moses, Marsha A; Schoen, Frederick J; Sacks, Michael S; Mayer, John E

    2010-01-01

    We investigated whether circulating endothelial progenitor cells (EPCs) can be used as a cell source for the creation of a tissue-engineered heart valve (TEHV). Trileaflet valved conduits were fabricated using nonwoven polyglycolic acid/poly-4-hydroxybutyrate polymer. Ovine peripheral blood EPCs were dynamically seeded onto a valved conduit and incubated for 7, 14, and 21 days. Before seeding, EPCs were shown to express CD31(+), eNOS(+), and VE-Cadherin(+) but not alpha-smooth muscle actin. Histological analysis demonstrated relatively homogenous cellular ingrowth throughout the valved conduit. TEHV constructs revealed the presence of endothelial cell (EC) markers and alpha-smooth muscle actin(+) cells comparable with native valves. Protein levels were comparable with native valves and exceeded those in unseeded controls. EPC-TEHV demonstrated a temporal pattern of matrix metalloproteinases-2/9 expression and tissue inhibitors of metalloproteinase activities comparable to that of native valves. Mechanical properties of EPC-TEHV demonstrated significantly greater stiffness than that of the unseeded scaffolds and native valves. Circulating EPC appears to have the potential to provide both interstitial and endothelial functions and could potentially serve as a single-cell source for construction of autologous heart valves.

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

    Science.gov (United States)

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

    2012-06-01

    Decellularized xenogenic or allogenic heart valves have been used as starter matrix for tissue-engineering of valve replacements with (pre-)clinical promising results. However, xenografts are associated with the risk of immunogenic reactions or disease transmission and availability of homografts is limited. Alternatively, biodegradable synthetic materials have been used to successfully create tissue-engineered heart valves (TEHV). However, such TEHV are associated with substantial technological and logistical complexity and have not yet entered clinical use. Here, decellularized TEHV, based on biodegradable synthetic materials and homologous cells, are introduced as an alternative starter matrix for guided tissue regeneration. Decellularization of TEHV did not alter the collagen structure or tissue strength and favored valve performance when compared to their cell-populated counterparts. Storage of the decellularized TEHV up to 18 months did not alter valve tissue properties. Reseeding the decellularized valves with mesenchymal stem cells was demonstrated feasible with minimal damage to the reseeded valve when trans-apical valve delivery was simulated. In conclusion, decellularization of in-vitro grown TEHV provides largely available off-the-shelf homologous scaffolds suitable for reseeding with autologous cells and trans-apical valve delivery. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Comparative study of cellular and extracellular matrix composition of native and tissue engineered heart valves.

    Science.gov (United States)

    Schenke-Layland, K; Riemann, I; Opitz, F; König, K; Halbhuber, K J; Stock, U A

    2004-05-01

    Tissue engineering of heart valves utilizes biodegradable or metabolizable scaffolds for remodeling by seeded autologous cells. The aim of this study was to determine and compare extracellular matrix (ECM) formations, cellular phenotypes and cell location of native and tissue engineered (TE) valve leaflets. Ovine carotid arteries, ovine and porcine hearts were obtained from slaughterhouses. Cells were isolated from carotid arteries and dissected ovine, porcine and TE leaflets. TE constructs were fabricated from decellularized porcine pulmonary valves, seeded ovine arterial cells and subsequent 16 days dynamic in vitro culture using a pulsatile bioreactor. Native and TE valves were studied by histology (hematoxylin-eosin, resorcin-fuchsin, Movat pentachrome), NIR femtosecond multiphoton laser scanning microscopy and scanning electron microscopy (SEM). Cells of native and TE tissues were identified and localized by immunohistochemistry. Arterial, valvular and re-isolated TE-construct cells were processed for immunocytochemistry and Western blotting. ECM analysis and SEM revealed characteristical and comparable structures in native and TE leaflets. Most cells in native leaflets stained strongly positive for vimentin. Cells positive to alpha-smooth muscle actin (alpha-SMA), myosin and calponin were only found at the ventricular (inflow) side of ovine aortic and porcine pulmonary valve leaflets. Cells from TE constructs had a strong expression of vimentin, alpha-SMA, myosin, calponin and h-caldesmon throughout the entire leaflet. Comparable ECM formation and endothelial cell lining of native and TE leaflets could be demonstrated. However, immunostaining revealed significant differences between valvular cell phenotypes of native and TE leaflets. These results may be essential for further cardiovascular tissue engineering efforts.

  17. Transcatheter aortic valve implantation using anatomically oriented, marrow stromal cell-based, stented, tissue-engineered heart valves: technical considerations and implications for translational cell-based heart valve concepts.

    Science.gov (United States)

    Emmert, Maximilian Y; Weber, Benedikt; Behr, Luc; Sammut, Sebastien; Frauenfelder, Thomas; Wolint, Petra; Scherman, Jacques; Bettex, Dominique; Grünenfelder, Jürg; Falk, Volkmar; Hoerstrup, Simon P

    2014-01-01

    While transcatheter aortic valve implantation (TAVI) has rapidly evolved for the treatment of aortic valve disease, the currently used bioprostheses are prone to continuous calcific degeneration. Thus, autologous, cell-based, living, tissue-engineered heart valves (TEHVs) with regeneration potential have been suggested to overcome these limitations. We investigate the technical feasibility of combining the concept of TEHV with transapical implantation technology using a state-of-the-art transcatheter delivery system facilitating the exact anatomical position in the systemic circulation. Trileaflet TEHVs fabricated from biodegradable synthetic scaffolds were sewn onto self-expanding Nitinol stents seeded with autologous marrow stromal cells, crimped and transapically delivered into the orthotopic aortic valve position of adult sheep (n = 4) using the JenaValve transapical TAVI System (JenaValve, Munich, Germany). Delivery, positioning and functionality were assessed by angiography and echocardiography before the TEHV underwent post-mortem gross examination. For three-dimensional reconstruction of the stent position of the anatomically oriented system, a computed tomography analysis was performed post-mortem. Anatomically oriented, transapical delivery of marrow stromal cell-based TEHV into the orthotopic aortic valve position was successful in all animals (n = 4), with a duration from cell harvest to TEHV implantation of 101 ± 6 min. Fluoroscopy and echocardiography displayed sufficient positioning, thereby entirely excluding the native leaflets. There were no signs of coronary obstruction. All TEHV tolerated the loading pressure of the systemic circulation and no acute ruptures occurred. Animals displayed intact and mobile leaflets with an adequate functionality. The mean transvalvular gradient was 7.8 ± 0.9 mmHg, and the mean effective orifice area was 1.73 ± 0.02 cm(2). Paravalvular leakage was present in two animals, and central aortic regurgitation due to a

  18. Cryopreserved semilunar heart valve allografts: leaflet surface damage in scanning electron microscopy.

    Science.gov (United States)

    Burkert, J; Krs, O; Vojácek, J; Mokrácek, A; Slízová, D; Hlubocký, J; Kobylka, P; Spatenka, J

    2008-08-01

    Allograft heart valves (AHV), biological valves of human origin, offer potential advantages over conventional xenografts in terms of superior hemodynamics and, perhaps, better durability. The most important factors for long-term AHV clinical performance are the processing and cryopreservation methods. The aim of this study was to evaluate the impact of current processing protocol on valve tissue morphology, mainly to address the effect of successive processing steps on the leaflet surface structure. For the detection of fine changes in endothelial covering and underlying layers, our own modification of the scanning electron microscopy (SEM) technique was utilized. The study was based on an investigation of 20 AHV (40 specimens). Fourteen valves came from heart-beating donors (multiorgan harvesting) when the heart could not be transplanted for any reason (donor criteria, availability of recipient and/or logistics). Six were obtained at the time of routine postmortems--non heart-beating donors (NHBD). All specimens were initially fixed in Baker's solution. Tissue samples were dissected, dried with hexamethyldisilazane (HMDS), gold-coated, studied and photographed by SEM (Tesla BS 301). In order to define the integrity of the endothelium, subendothelial layers and the quality of the surface under SEM, a special six-level score system was introduced: 1-intact endothelium, 2-confluent endothelium with structural inhomogeneity, 3-disruption of intercellular contacts, 4-separation of endothelial cells, 5-complete loss of endothelium, 6-damage of subendothelial layers). AHV samples were divided into 4 groups for comparison. One aortic AHV "fresh" control sample obtained from a heart-beating donor was evaluated without any processing and was compared with (i) tissue from AHV obtained from NHBD with warm ischemia of 12 and 48 hours, (ii) samples stored at +4 degrees C in saline for 24 h, (iii) antibiotic-treated tissue for 24 h at 37 degrees C and finally with (iv

  19. The in vitro development of autologous fibrin-based tissue-engineered heart valves through optimised dynamic conditioning.

    Science.gov (United States)

    Flanagan, Thomas C; Cornelissen, Christian; Koch, Sabine; Tschoeke, Beate; Sachweh, Joerg S; Schmitz-Rode, Thomas; Jockenhoevel, Stefan

    2007-08-01

    Our group has previously demonstrated the synthesis of a completely autologous fibrin-based heart valve structure using the principles of tissue engineering. The present approach aims to guide more mature tissue development in fibrin-based valves based on in vitro conditioning in a custom-designed bioreactor system. Moulded fibrin-based tissue-engineered heart valves seeded with ovine carotid artery-derived cells were subjected to 12 days of mechanical conditioning in a bioreactor system. The bioreactor pulse rate was increased from 5 to 10 b.p.m. after 6 days, while a pressure difference of 20 mmH(2)O was maintained over the valve leaflets. Control valves were cultured under stirred conditions in a beaker. Cell phenotype and extracellular matrix (ECM) composition were analysed in all samples and compared to native ovine aortic valve tissue using routine histological and immunohistochemical techniques. Conditioned valve leaflets showed reduced tissue shrinkage compared to stirred controls. Limited ECM synthesis was evident in stirred controls, while the majority of cells were detached from the fibrin scaffold. Dynamic conditioning increased cell attachment/alignment and expression of alpha-smooth muscle actin, while enhancing the deposition of ECM proteins, including types I and III collagen, fibronectin, laminin and chondroitin sulphate. There was no evidence for elastin synthesis in either stirred controls or conditioned samples. The present study demonstrates that the application of low-pressure conditions and increasing pulsatile flow not only enhances seeded cell attachment and alignment within fibrin-based heart valves, but dramatically changes the manner in which these cells generate ECM proteins and remodel the valve matrix. Optimised dynamic conditioning, therefore, might accelerate the maturation of surgically feasible and implantable autologous fibrin-based tissue-engineered heart valves.

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

    Science.gov (United States)

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

    2016-01-01

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

  1. Percutaneous Edwards SAPIEN valve implantation in the tricuspid position : case report and review of literature

    NARCIS (Netherlands)

    Hoendermis, Elke S.; Douglas, Yvonne L.; van den Heuvel, Ad F. M.

    Aims: Experience with transcatheter valve-in-valve implantation in a failing bioprosthetic tricuspid valve is very limited. Fewer than 30 cases have been reported, and in most of them the Melody valve (Medtronic, Inc., Minneapolis, MN, USA) was used. With this case report and review of literature we

  2. Off-the-shelf tissue engineered heart valves for in situ regeneration: current state, challenges and future directions.

    Science.gov (United States)

    Motta, Sarah E; Lintas, Valentina; Fioretta, Emanuela S; Hoerstrup, Simon P; Emmert, Maximilian Y

    2018-01-01

    Transcatheter aortic valve replacement (TAVR) is continuously evolving and is expected to surpass surgical valve implantation in the near future. Combining durable valve substitutes with minimally invasive implantation techniques might increase the clinical relevance of this therapeutic option for younger patient populations. Tissue engineering offers the possibility to create tissue engineered heart valves (TEHVs) with regenerative and self-repair capacities which may overcome the pitfalls of current TAVR prostheses. Areas covered: This review focuses on off-the-shelf TEHVs which rely on a clinically-relevant in situ tissue engineering approach and which have already advanced into preclinical or first-in-human investigation. Expert commentary: Among the off-the-shelf in situ TEHVs reported in literature, the vast majority covers pulmonary valve substitutes, and only few are combined with transcatheter implantation technologies. Hence, further innovations should include the development of transcatheter tissue engineered aortic valve substitutes, which would considerably increase the clinical relevance of such prostheses.

  3. Durability of bioprostheses for the tricuspid valve in patients with congenital heart disease.

    Science.gov (United States)

    Burri, Melchior; Vogt, Manfred O; Hörer, Jürgen; Cleuziou, Julie; Kasnar-Samprec, Jelena; Kühn, Andreas; Lange, Rüdiger; Schreiber, Christian

    2016-11-01

    Only little data exist on the durability of bioprostheses in the tricuspid position in patients with congenital heart disease (CHD). The aim of the study was to determine the reoperation rate and the valve function after primary implantation. Between 1990 and 2013, 51 patients with CHD underwent tricuspid valve (TV) replacement with a bioprosthesis. The median age at operation was 32 years (range: 8-69). The underlying morphology was Ebstein's anomaly in 62% of the patients. Implanted valves included 38 pericardial and 13 porcine valves. All available echocardiographic examinations (n = 714) and clinical data were retrospectively reviewed. Dysfunction was defined as an at least moderate regurgitation or a mean diastolic gradient ≥9 mmHg. Freedom from death, reoperation and prosthetic valve dysfunction was estimated using the Kaplan-Meier method. The 30-day mortality rate was 9%. The estimated survival rate was 86% at one and 80% at ten years. The freedom from reoperation at 1, 5 and 10 years was 100, 86 and 81%, and that from prosthesis dysfunction detected by echocardiography at 1, 5 and 10 years was 89, 66 and 58%, respectively. The main reason for dysfunction was insufficiency (89%). Valve implantation at an age below 16 years was associated with earlier reoperation and dysfunction (the 5-year freedom rate from reoperation/dysfunction was 70%/30% compared with 89%/78% in the rest of the patients, P = 0.016/0.0009). Serial echocardiography shows a high rate of dysfunction of TV bioprosthesis in patients with CHD, which already occurred a few years after implantation. In patients below 16 years of age, most prostheses are dysfunctional within 5 years. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  4. 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.

  5. 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 de