Journal articles on the topic 'Heart valve prosthesis'
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1
Briffa, Norman Paul. "Results of mechanical versus tissue AVR: caution in young patients with tissue AVR." Heart 105, Suppl 2 (March 2019): s34—s37. http://dx.doi.org/10.1136/heartjnl-2018-313516.
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The first aortic valve prosthesis, implanted more than 50 years ago, was a mechanical prosthesis (ball-and-cage design). Over the ensuing decades, tissue prostheses and new mechanical designs were introduced to mitigate the need for anticoagulation with its associated side effects. Tissue and mechanical heart valve prostheses were compared in two head-to-head randomised control trials. Both of these confirmed that mechanical prostheses were durable but patients suffered anticoagulant-related bleeds. Patients who received a tissue prosthesis were more likely to suffer prosthetic dysfunction and require reoperation. This trend was stronger in younger patients. Since the publication of those two trials, several large retrospective studies using data from meta-analyses of published papers or registries have failed to show a survival advantage of either prostheses when implanted in the aortic position in younger patients. This equipoise has been reflected in the heart valve disease guidelines published by European and US societies. In recent years, the primacy of patient choice, the rapid increase in life expectancy of populations, the increased incidence of atrial fibrillation with requirement for anticoagulation, the advent of transcatheter techniques to treat degenerating tissue valves as well as advances in anticoagulant therapy and in new tissue and to a lesser extent mechanical prosthetic design continue to influence choice of aortic valve prosthesis in younger patients undergoing aortic valve replacement.
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Ingimarsdóttir, I. J., L. Hellgren Johansson, and F. A. Flachskampf. "Preoperative aortic annulus size assessment by transthoracic echocardiography compared to the size of surgically implanted aortic prostheses." Echo Research and Practice 6, no. 2 (June 2019): 37–41. http://dx.doi.org/10.1530/erp-19-0010.
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Objectives The aortic annulus diameter measured by transthoracic echocardiography yields lower values than by computed tomography, and echo-based selection of transcatheter aortic valve prosthesis size has been implied to result in more frequent paravalvular leakage. We investigated the relation of preoperative annulus diameter by echo with the ring size of the aortic prosthesis chosen by direct assessment during open-heart aortic valve replacement. Methods Preoperative annulus diameter by echo (from parasternal long-axis cross-sections of the left ventricular outflow tract and aortic valve) and implanted prosthetic diameter (tissue annulus diameter, determined intraoperatively using a sizing instrument) were compared retrospectively in 285 consecutive patients undergoing open-heart aortic valve replacement. Results A total of 285 prostheses (240 biologic and 45 mechanical) were implanted, with prosthetic diameter ranging between 19 and 27 mm. There was a significant linear correlation (P < 0.0001) with r = 0.51, between preoperative annulus diameter by echo (mean 21.8 ± 2.8 mm) and prosthetic diameter (22.9 ± 1.7 mm). Preoperative annulus diameter of patients receiving prostheses no. 21, 23 and 25 mm aortic prostheses (the most frequent prosthesis sizes) were significantly different (P < 0.001) from each other. On average, preoperative annulus diameter by echo underestimated prosthetic diameter by a bias of 1.07 mm. Conclusion Our data confirm that preoperative echo assessment of the aortic valve may slightly underestimates the optimal surgical prosthesis diameter for the aortic valve annulus.
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Perekopskaya, Veronika S., Nataliya A. Morova, and Valeriy N. Tsekhanovich. "The structural-geometric and functional parameters of the heart in patients after mitral prosthetics with new full-flow valves in the long-term period." CardioSomatics 13, no. 1 (July 29, 2022): 4–10. http://dx.doi.org/10.17816/22217185.2022.1.201469.
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Aim. To compare the results of mitral valve replacement with the full-flow mechanical valve MedInzh-ST and the classical prosthesis MedInzh-2, to learn the structural and functional parameters of the heart depending from the prosthesis in the long-tern period.
Material and methods. From 2015 to February 2020 years an the basis of the cardio-surgical department of the Regional clinical Hospital 116 patients, in order to correct defects, were underwent mitral prosthetics with MedInzh valves. Of these 55 patients received a new full-flow valve MedInzh-ST. 61 patients a classical MedInzh-2. Before surgery and in the long-term period all patients were underwent transthoracic echocardiography with using expert-class devices. In the long-tern postoperative period 34 patients were underwent echocardiographic research after implantation full-flow valves and 40 patients after prosthetics of classical prosthesis.
Results. The choice of the prosthesis model did not affect the incidence of postoperative complications and the rate of hospital mortality. In all cause of death is not associated with impaired function of the prosthesis. All patients before the discharge from hospital were fixed the positive effect from surgical treatment. In the long-term postoperative period between patients after implantation of full-flow valves, the cases of prosthetic platelets were not registered. One patient was diagnosed with prosthetic thrombosis after implantation of a classical prosthesis, which required further reprosthetics. There were no signs of prosthetic endocarditis and paraprosthetic fistula in both groups. There were no significant differences in the structural and geometric parameters of the heart in all patients.
Conclusion. Analysis of the functional characteristics of the new full-flow valve MedInzh-ST in the long-term period allows us to conclude that the new valve model meets modern requirements for efficiency and safety.
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Schröter, Filip, Ralf-Uwe Kühnel, Martin Hartrumpf, Roya Ostovar, and Johannes Maximilian Albes. "Progress on a Novel, 3D-Printable Heart Valve Prosthesis." Polymers 15, no. 22 (November 15, 2023): 4413. http://dx.doi.org/10.3390/polym15224413.
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(1) Background: Polymeric heart valves are prostheses constructed out of flexible, synthetic materials to combine the advantageous hemodynamics of biological valves with the longevity of mechanical valves. This idea from the early days of heart valve prosthetics has experienced a renaissance in recent years due to advances in polymer science. Here, we present progress on a novel, 3D-printable aortic valve prosthesis, the TIPI valve, removing the foldable metal leaflet restrictor structure in its center. Our aim is to create a competitive alternative to current valve prostheses made from flexible polymers. (2) Methods: Three-dimensional (3D) prototypes were designed and subsequently printed in silicone. Hemodynamic performance was measured with an HKP 2.0 hemodynamic testing device using an aortic valve bioprosthesis (BP), a mechanical prosthesis (MP), and the previously published prototype (TIPI 2.2) as benchmarks. (3) Results: The latest prototype (TIPI 3.4) showed improved performance in terms of regurgitation fraction (TIPI 3.4: 15.2 ± 3.7%, TIPI 2.2: 36.6 ± 5.0%, BP: 8.8 ± 0.3%, MP: 13.2 ± 0.7%), systolic pressure gradient (TIPI 3.4: 11.0 ± 2.7 mmHg, TIPI 2.2: 12.8 ± 2.2 mmHg, BP: 8.2 ± 0.9 mmHg, MP: 10.5 ± 0.6 mmHg), and effective orifice area (EOA, TIPI 3.4: 1.39 cm2, TIPI 2.2: 1.28 cm2, BP: 1.58 cm2, MP: 1.38 cm2), which was equivalent to currently used aortic valve prostheses. (4) Conclusions: Removal of the central restrictor structure alleviated previous concerns about its potential thrombogenicity and significantly increased the area of unobstructed opening. The prototypes showed unidirectional leaflet movement and very promising performance characteristics within our testing setup. The resulting simplicity of the shape compared to other approaches for polymeric heart valves could be suitable not only for 3D printing, but also for fast and easy mass production using molds and modern, highly biocompatible polymers.
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Bloomfield, P. "Choice of heart valve prosthesis." Heart 87, no. 6 (June 1, 2002): 583–89. http://dx.doi.org/10.1136/heart.87.6.583.
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Nazarov, V. M., S. I. Zheleznev, A. V. Bogachev-prokofev, A. V. Afanasev, I. I. Demin, and D. A. Astapov. "Comparative studies of modern mechanical valve prosthesis (review)." Patologiya krovoobrashcheniya i kardiokhirurgiya 17, no. 2 (October 10, 2015): 79. http://dx.doi.org/10.21688/1681-3472-2013-2-79-84.
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More than 50 years have passed since the first successful heart valve replacement. Since then, many types of mechanical prostheses have been introduced. The prosthesis choice for the replacement of an affected valve is a major concern in valvular surgery. The introduction of a new heart valve prosthesis requires accurate data collection and data processing for a long follow-up period. In present article we sought to compare modern commercial available bileaflet foreign mechanical valve prosthesis for their long follow-up with Russian mechanical valve for aortic and mitral valve replacement.
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Gramatikov, D. G., V. S. Litus, V. K. Noginov, K. E. Budanov, and K. V. Samko. "Replacement of aortic valve flaps with an autopericardium using the S. Ozaki technique." Grekov's Bulletin of Surgery 181, no. 3 (July 4, 2022): 81–84. http://dx.doi.org/10.24884/0042-4625-2022-181-3-81-84.
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Classical aortic valve replacement is often fraught with negative outcomes for patients. When replacing the aortic valve with a mechanical valve prosthesis, the patient is associated for life with the use of indirect anticoagulants, which often leads to hemorrhagic and thrombotic complications. In the case of replacement of the aortic valve with a biological prosthesis, a fairly frequent complication is early calcification and, consequently, a high frequency of dysfunctions of the biological prosthesis. In addition, mechanical and biological prosthetics of heart valves are quite expensive, which creates a serious economic load on the healthcare institution. But in the last decade, the technique of neocuspidization of the aortic valve with autopericardial flaps has been introduced into wide cardiac surgical practice, which is a clear alternative to prosthetics of heart valves.
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Klyshnikov, K. Yu, E. A. Ovcharenko, A. N. Stasev, T. V. Glushkova, Yu A. Kudryavtseva, and L. S. Barbarash. "Experimental substantiation of the design of a prosthetic heart valve for «valve-in-valve» implantation." Russian Journal of Transplantology and Artificial Organs 19, no. 2 (June 23, 2017): 69–77. http://dx.doi.org/10.15825/1995-1191-2017-2-69-77.
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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 of the developed design, intended for the replacement of a failed prosthetic valve of the heart with the «valve-in-valve» implantation.
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Wysokinska, Ewa M., Katherine M. Duello, Dong Chen, and Joseph L. Blackshear. "Evaluation of Prosthetic Valve Function by Platelet Function Analysis and Von Willebrand Factor Indices." Blood 120, no. 21 (November 16, 2012): 1128. http://dx.doi.org/10.1182/blood.v120.21.1128.1128.
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Abstract Abstract 1128 Background Dysfunctional or mismatched prosthetic heart valves can results in high shear stress related von Willebrand factor (VWF) impairment, and clinical bleeding. This mechanism is similar to that seen in aortic stenosis patients, where gastrointestinal bleeding related to VWF multimer loss is well described (Heyde syndrome). In this study, we compared the results of VWF testing of patients with normally functioning cardiac valve prostheses, dysfunctional prosthetic valves, severe native aortic stenosis, and normal controls. Methods A total of 75 patients, 31 female and 44 male with a median age of 79.5 years were recruited to this study. Thirty patients had severe aortic stenosis (mean gradient > 40 mm Hg); 39 patients had normally functioning prosthetic valves, 21 aortic (AVR) and 18 mitral valves (MVR); and 6 patients had with dysfunctional valves (4 aortic and 2 mitral). Whole blood and plasma samples were drawn from patients and tested for platelet function analyzer-100 collagen ADP closure time (PFA-CADP), VWF antigen (VWF:Ag), VWF activity by latex immunoassay (VWF:Ltx), VWF multimer analysis and VWF multimer densitometry ratio of large vs medium to low molecular weight multimers (>15 mers/2–15 mers). Results The 6 dysfunctional prosthetic valve patients included patient-prosthesis mismatch (2) and (one each), thrombosed mechanical aortic prosthesis, torn biological aortic prosthesis, severe tissue mitral prosthetic regurgitation, and post-mitral valve repair severe mitral regurgitation. Four of six patients had clinically significant bleeding. Most aortic stenosis and all 6 prosthetic dysfunction patients had abnormal VWF multimers which is rare in normally functioning prostheses and completely absent in normal donors. VWF:Ltx/Ag was lower in AS and MVR than normal. VWF:Ltx/Ag ratio, VWF:multimer ratio and PFA-CADP were all significantly abnormal in patients with dysfunctional prosthetic valve. VWF:multimer ratios in normally functioning prostheses tended to be intermediate between normals and than those of patients with severe AS or prosthetic valve dysfunction (Table). Conclusions VWF testing including quantitative von Willebrand multimer analysis and PFA-CADP reliably separate dysfunctional from normally functioning cardiac prostheses, and should be considered in the evaluation of patients with cardiac prostheses, especially those who have clinically significant bleeding. Disclosures: No relevant conflicts of interest to declare.
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Klyshnikov, K. Yu, E. A. Ovcharenko, Yu A. Kudryavtseva, and L. S. Barbarash. "Hydrodynamic performance of a novel suturelessprosthetic aortic valve." Russian Journal of Transplantology and Artificial Organs 22, no. 2 (July 12, 2020): 117–24. http://dx.doi.org/10.15825/1995-1191-2020-2-117-124.
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The aim of the study was an in vitro hydrodynamic study of the developed prosthetic heart valve of the second generation, designed to carry out an implantation using «valve-in-valve» method. Material and methods. Prototypes of the developed prosthesis were studied under simulated physiological conditions of the heart using a Vivitro Labs pulse duplicator (Canada) in a comparative aspect with «UniLine» clinical commercial aortic valve bioprosthesis (Russia). Samples were tested by simulating sutureless implantation procedure. Results. The developed valves showed satisfactory hydrodynamic characteristics – for all cases of «implantation» from the position of the average trans-prosthetic gradient (6.1–11.1 mm Hg) and the effective orifice area (1.60–1.81 cm2 ). The analysis of the regurgitation fraction allowed us to determine the optimal sizes for implantation using «valvein-valve» method, which subsequently will form the basis of sizing guidelines for size selection. A qualitative analysis of the leaflet’s work demonstrated the presence of slight asymmetry for a number of prostheses – in case of mismatch of sizes when simulating «valve-in-valve» procedure. Conclusion. The tests demonstrate the viability of the developed design from the standpoint of hydrodynamic efficiency and determines the basic rules of selecting a prosthesis for reimplantation relative to the primary valve.
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Zhang, Cheng, Jiangtao Hao, Weiliang Shi, Ya Su, Kellen Mitchell, Weijian Hua, Wenbo Jin, et al. "Sacrificial scaffold-assisted direct ink writing of engineered aortic valve prostheses." Biofabrication 15, no. 4 (August 24, 2023): 045015. http://dx.doi.org/10.1088/1758-5090/aceffb.
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Abstract Heart valve disease has become a serious global health problem, which calls for numerous implantable prosthetic valves to fulfill the broader needs of patients. Although current three-dimensional (3D) bioprinting approaches can be used to manufacture customized valve prostheses, they still have some complications, such as limited biocompatibility, constrained structural complexity, and difficulty to make heterogeneous constructs, to name a few. To overcome these challenges, a sacrificial scaffold-assisted direct ink writing approach has been explored and proposed in this work, in which a sacrificial scaffold is printed to temporarily support sinus wall and overhanging leaflets of an aortic valve prosthesis that can be removed easily and mildly without causing any potential damages to the valve prosthesis. The bioinks, composed of alginate, gelatin, and nanoclay, used to print heterogenous valve prostheses have been designed in terms of rheological/mechanical properties and filament formability. The sacrificial ink made from Pluronic F127 has been developed by evaluating rheological behavior and gel temperature. After investigating the effects of operating conditions, complex 3D structures and homogenous/heterogenous aortic valve prostheses have been successfully printed. Lastly, numerical simulation and cycling experiments have been performed to validate the function of the printed valve prostheses as one-way valves.
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Adhikary, Asit Baran, Redoy Ranjan, Musfiqur Rahman, Dipannita Adhikary, Sanjoy Kumar Saha, and Heemel Saha. "Outcome of heart valve prosthesis in Bangladesh: A retrospective study." Bangladesh Medical Research Council Bulletin 45, no. 3 (December 30, 2019): 163–69. http://dx.doi.org/10.3329/bmrcb.v45i3.44646.
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Background: Prosthetic heart valve for middle aged patients requiring valve replacement remains controversialBecause of the co-morbidities and limited life expectancy, bioprosthesis is the likely choice for older aged patients.
Objective: The aim of the study was to quantify long term survival rate and major morbidity in patients undergoing heart valve replacement and to optimise selection criteria of biologic versus mechanical valve prostheses.
Methods: This retrospective cohort study evaluated among 565 patients of 45 to 65 years of age undergoing isolated, primary heart valve replacement in either aortic or mitral position using mechanical or bioprosthetic valve.
Results:Long time survival benefit was similar between aortic valve replacement (AVR) versus mitral valve replacement (MVR) patients regarding replacement with either mechanical and bioprosthetic valve. Postoperative incidence of morbidities like valve related complications, endocarditis, and bleeding were statistically not significant in this study. There was no significant difference in terms mortality after both AVR and MVR regarding use of bioprosthesis versus mechanical valve. Although, most common causes of mortality were prosthesis related and haemorrhage that was observed in both study group. Follow up at 10 years observed mean survival rate were 86.6%, 90.3% in mechanical AVR and MVR respectively, whereas patients with bioprosthesis demonstrate survival rate of 82.3% after AVR and 76.9% following MVR.
Conclusion: With a life expectancy of at least 15 years, mechanical prostheses should be considered in patients below 50 years in Bangladesh. However, patients more than 50 years of age or with multiple comorbidities like coronary artery disease, renal disease, lung disease, coronary disease, or a life expectancy less than 15 years, bio prostheses may be good options for better outcome.
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PRETRE, R. "Thrombosis of a mitral valve prosthesis." Heart 83, no. 1 (January 1, 2000): 34. http://dx.doi.org/10.1136/heart.83.1.34.
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Scollo, V., G. Fede, G. Abate, P. Belluardo, N. Guccione, G. Sulsenti, and S. Ficili. "P272 ROLE OF 3D TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN DIANOSIS OF DYSFUNCTION OF MECHANICAL PROSTHESES." European Heart Journal Supplements 25, Supplement_D (May 2023): D146. http://dx.doi.org/10.1093/eurheartjsupp/suad111.346.
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Abstract Infections with endocardial vegetation or the exuberant growth of neoendothelialization tissue (cloth –tissue overgrowth) in heart valve prostheses lead, among other complications, to the malfunction of the prostheses themselves due to obstruction. Among the diagnostic methods available to us, to achieve the diagnosis of prosthetic dysfunction, in recent years three–dimensional transesophageal echocardiography (3D TTE) has become increasingly imposed. We present two clinical cases of patients admitted to our Cardiology department Case 1: Patient of 62 years old, hospitalized for established congestive heart failure. In 2006 he underwent ascending aorta replacement with Dacron 28 prosthesis and aortic valve replacement with mechanical prosthesis (Sorin 25) for aortic bicuspid and ascending aortic aneurysm. During the last follow–up was observed a slight increase in the value of intraprosthetic gradients, as well as a variability in INR values. Physical examination showed signs of heart failure (NT–ProBNP >1000 pg/ml); normal inflammation indices (PCR <2.9 mg/l); ECG: sinus rhythm at 85 bpm with left ventricular overload; trans–thoracic echocardiography showed severe intraprosthetic aortic gradient (Gmax 132mmHg–Gmed 72mmHg), doubtful for cloth adhered to prosthetic discs; 3D TTE shoved hyperechoreflective image adhered to the posterior mobile element (5x9mm) which was fixed in semi–closure. Subsequently, the patient underwent prosthetic replacement surgery with biological prosthesis. Case 2: Patient of 67 years old, heavy smoker, hypertensive, with aortic mechanical prosthesis, a few weeks before hospitalized for Corynebacterium Jeikeium infection. Hospitalized again for fever with increased inflammation indices (CRP 202mg/l). A first TTE concluded for suspected endocarditis of the prosthesis; this doubt was also dissolved by 3D TTE which showed a soft protruding image of the posterior mobile element, preventing the opening and determining severe stenosis (Gmax 160mmHg–Gmed of 80 mmHg), so this patients was transferred to the cardiac surgery department. Conclusions 3D TTE is a method of rapid and safe execution that can be exploited not only pre– or intraoperatively but also to settle diagnostic suspicions not clarified by traditional 2d methods, even managing to distinguish cloth deposits from vegetation / abscesses.
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de Oliveira Ramos, Auristela Isabel, Mariana Oliveira Rezende, Guilherme Séer da Silva, and Andréia Dias Jerônimo. "PRÓTESE VALVAR CARDÍACA." Revista da Sociedade de Cardiologia do Estado de São Paulo 32, no. 2 (June 1, 2022): 175–82. http://dx.doi.org/10.29381/0103-8559/20223202175-82.
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A troca valvar para correção das valvopatias importantes deve ser indicada no momento correto da história natural da doença valvar para evitar as possíveis conse-quências irreversíveis. O substituto valvar ideal deve ter as seguintes características: ausência de ruído, boa durabilidade, ter fácil implante, ser composto por um tecido não trombogênico, não antigênico e que não precise anticoagulação permanente. Apesar de ainda não existir um substituto valvar com as características ideais, as próteses, biológicas ou mecânicas, evoluíram significativamente nas últimas décadas, em relação ao desenho, ao material utilizado, à forma de conservação e à técnica de implante, o que resultou em redução do risco de trombose da prótese e de fenômeno embólico, e menor necessidade de reoperação. Na escolha do substituto ideal, deve haver um equilíbrio entre o risco de trombose, o risco do sangramento e a necessidade de reope-ração, e deve sempre ser compartilhada com o paciente, levando em consideração fatores ligados ao paciente, à doença valvar e à prótese. Os pacientes com prótese valvar podem apresentar complicações relativas à disfunção secundária à degeneração estrutural, não estrutural, trombose e endocardite.
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Das, Devishree, Lakshya Sehgal, Ameya karanjkar, Sandeep Sharan, and Poonam Malhotra Kapoor. "Is TEE a Game Changer in Aortic Prosthetic Paravalvular Leak?" Journal of Cardiac Critical Care TSS 03, no. 01 (August 2019): 42–44. http://dx.doi.org/10.1055/s-0039-1696909.
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AbstractValve prosthesis have played an important role in the management of patients with valvular heart disease. However, the prosthetic heart valves used are not without complications. Almost all prosthetic heart valves are obstructive compared with native valves and associated with physiological washing jets. Because of shielding and artifacts it is very difficult to assess the prosthetic valve with TTE. Multiple thrombi and aortomitral continuity detection is cumbersome by TTE. Multiple angulations and off axis view in TEE help not only to characterize the prosthetic heart valve but also gives a three-dimensional surgical view to aid in reaching a diagnosis.
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P, Candela, Ajello L, Valerio MCE, Camarda P, Mineo V, Castelluccio EV, and Rebulla E. "Early failure of prosthetic valve presenting with acute heart failure." Journal of Cardiovascular Medicine and Cardiology 10, no. 4 (November 7, 2023): 051–53. http://dx.doi.org/10.17352/2455-2976.000201.
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Background: Early failure of cardiac biological prostheses refers to the deterioration or malfunction of the valve sooner than expected. These prostheses are designed to last for many years, even decades, but in some cases, they may fail within a much shorter timeframe. Early failure can manifest in various ways, including structural issues, valve stenosis, regurgitation, and reduced functionality. Understanding the causes of early failure is crucial for improving patient outcomes. Case presentation: We present the case of failure of a biological prosthesis implanted five years prior; the onset was rapid and acute (worsening dyspnea three days before access to the emergency room). A transcatheter mitral valve replacement was planned. Unfortunately, the patient expired before the procedure. Discussion: Although rare, early failure of biological valve prosthesis is possible. So, when treating a patient with a history of valve surgery presenting with acute heart failure, the suspicion of valve failure should be always considered.
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Rogulina, N. V., and I. K. Khalivopulo. "“Valve-On-Valve” — an alternative method of surgical treatment of tissue valve dysfunctions." Russian Journal of Cardiology, no. 8 (September 20, 2019): 140–49. http://dx.doi.org/10.15829/1560-4071-2019-8-140-149.
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Every year, the frequency of use of biological prostheses for treatment of valvular heart disease increases.The implantation of a biological prosthesis allows avoiding lifelong anticoagulant therapy, but at the same time it may require further replacement due to the dysfunction development.Traditional reoperation is associated with a certain risk of trauma to various structures and cardiac chambers during explantation of non-functioning valve.Transcatheter replacement of the prosthesis (“valve-in-valve”) is not always realizable due to lack of routes for the delivery system and small diameter of the initial valve.“Valve-in-valve” is not always demanded because it does not provide an option to choose mechanical or biological prosthesis.Valve-on-valve implantation technique implies that the new prosthesis is implanted in the carcass of the previous valve. It allows avoiding severe intraoperative complications, reducing the duration of the main stage of the surgery and adverse events in the early postoperative period, and provide an option to choose implantable device.In this review, the authors attempted to comprehensively evaluate the world experience in applying the “valve-on-valve” technique.
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Wassef, Bishoy, Mina Masry, Mounir Ghali, John N. Makaryus, and Amgad N. Makaryus. "Dynamic Echocardiographic Imaging of a Valve-in-Valve Mitral Prosthesis." Case Reports in Radiology 2022 (February 16, 2022): 1–4. http://dx.doi.org/10.1155/2022/1366037.
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Dynamic imaging of heart valves and specifically prosthetic valves is a central benefit of echocardiography. Most bioprosthetic heart valves degenerate over a given time and hence require repeat valve replacement which carries a significant risk of morbidity and mortality. Reoperation is the standard of care and may still be required after the first successful surgery due to complications disrupting either mechanical or bioprosthetic valves. Such complications can be delayed or even prevented if optimal prosthesis selection is individualized according to patients’ medical and postimplantation follow-up. We present the case of an 84-year-old woman where an open-heart valve-in-valve approach, implanting a mechanical valve in a failed bioprosthetic valve, produced a unique image on transthoracic echocardiography which needs to be recognized by imagers for appropriate patient diagnosis and management.
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Zheltovskii, Yu V., V. I. Batekha, E. V. Peshkov, and V. A. Podkamennyy. "A case report of successful surgical treatment of mitral valve disease 38 years after implantation of ball-valve mechanical prosthesis in aortic position." Patologiya krovoobrashcheniya i kardiokhirurgiya 26, no. 1 (March 31, 2022): 83. http://dx.doi.org/10.21688/1681-3472-2022-1-83-89.
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<p>The application of ball-valve prostheses in clinical practice marked a new age in the treatment of valvular heart pathology. Ball-valve prostheses are made of long-living and hard-wearing materials; however, these properties confer significant disadvantages resulting from the large dimensions and weight, increased pressure gradient and risk of valve thrombosis and systemic embolism. With the advent of more advanced disk structures, the use of ball-valve prostheses was ended.</p><p>In Russia and other counties, the scientific literature shows an increase in reoperation after implantation of ball-valve prostheses over the long-term, which is associated with the occurrence of another valve defect. The need to replace a functioning ball-valve prosthesis with a modern mechanical or biological prostheses during surgery for another valve is still controversial.</p><p>We present a case report of a 55-year-old patient with rheumatic mitral stenosis and functional insufficiency of the tricuspid valve, who underwent repeat surgery 38 years after implantation of a ball-valve prosthesis in the aortic position. From the echocardiography findings, the peak transmitral gradient was 16 mm Hg, the average gradient was 5.5 mm Hg, the area was 1.3 cm<sup>2</sup> and regurgitation was third-degree. On the tricuspid valve, there was third-degree regurgitation.</p><p>Adequate hemodynamic parameters of the ball-valve prosthesis (the maximum blood flow rate was 2.65 m/sec, the peak gradient was 30 mm Hg, the average gradient was 18 mm Hg and there was no regurgitation) and the absence of valve-dependent complications enabled us to perform mitral prosthetics and tricuspid valve plastic surgery without replacing the aortic prosthesis, which reduced the operation time and decreased the risk of complications.</p><p>The patient was examined two years later. The patient’s active lifestyle and adequate hemodynamic parameters proved the rationality of our treatment policy.</p><p>The reported case indicates that mitral valve defect that develops a long time after aortic valve prosthetics can be treated surgically without the replacement of a ball-valve prosthesis in the case that it has good function.</p><p>Received 25 July 2021. Revised 22 August 2021. Accepted 23 August 2021.</p><p><strong>Funding:</strong> The study did not have sponsorship.</p><p><strong>Conflict of interest:</strong> Authors declare no conflict of interest.</p><p><strong>Contribution of the authors:</strong> The authors contributed equally to this article.</p>
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Manes, Maria Teresa, Anna Rita Ritacco, Susanna Cassano, Maria Teresa Ferrò, Bruno Manduca, Carmen Spaccarotella, and Domenico Musacchio. "The Heart Team during the Pandemic: A Case Report of Bio-Prosthesis Degeneration Treated with Valve in Valve Implantation." Journal of Cardiovascular Echography 34, no. 2 (April 2024): 77–81. http://dx.doi.org/10.4103/jcecho.jcecho_12_23.
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The pandemic changed the type of patients. The concept of “patient at the center” became concrete. The execution of simple consultancy was overcome to create effective collaboration and fruitful exchanges between specialists. The “Heart Team” model is on increasing affirmation. The TEAM-BASED approach in the cardiology field is successfully used in patients suffering from ischemic heart disease and valvulopathies for the choice of possible treatments. Degenerative type Sao is the most frequent valvulopathy among the valvulopathies in Western countries and its incidence is correlated with age. In high-risk patients, percutaneous valve replacement (transcatheter aortic valve implantation) is the most valid therapeutic option. The implantation of biological prostheses raises the problem of both degeneration and dysfunction of the prosthesis itself over time in subjects of advanced age and with comorbidities. In this scenario, valve-in-valve (VinV) is a valid therapeutic alternative in high-risk patients. A clinical case of aortic prosthetic degeneration, as an outcome of endocarditis, treated with VinV is presented. The therapeutic decision was made by an “Electronic Heart Team” which represents a further evolution of the treatment pathways and reduces the distance between the specialists in “Hub” Centers and the “Spoke” center. Summary The advent of the pandemic caused active collaboration and fruitful discussions among medical specialists. As a matter of fact, a shift from a simple consultation to the establishment of a proper “Heart Team” model occurred and the concept of “patient at the center” arose. TEAM-BASED approaches in cardiology are being successfully used as possible treatments in patients suffering from ischemic heart disease and valvulopathies. Degenerative type Sao is the most frequent valvulopathy in Western countries and its incidence is correlated with age. In high-risk patients, percutaneous valve replacement (TAVI) is the most viable treatment option. However, in subjects of advanced age, with comorbidities, the implantation of biological prostheses is associated with the degeneration and dysfunction of the prosthesis itself over time. In this scenario, Valve-in-valve (VinV) is a viable therapeutic alternative in high-risk patients. A clinical case of aortic prosthetic degeneration, as an outcome of endocarditis, that was treated with VinV is presented. The decision on VinV was made by an “Electronic Heart Team” which represents a further evolution of care pathways to reduce the distance between the “Hub” Centers and the specialist at the “Spoke” center.
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Babenko, S. I., N. N. Soboleva, N. P. Bakuleva, D. A. Titov, and R. M. Muratov. "LONG-TERM RESULTS OF MITRAL AND AORTIC VALVE REPLACEMENT WITH XENOPERICARDIAL PROSTHESIS «BIOLAB»." Complex Issues of Cardiovascular Diseases 7, no. 2 (June 30, 2018): 61–70. http://dx.doi.org/10.17802/2306-1278-2018-7-2-61-70.
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Background Heart valve replacement with mechanical prostheses in elderly patients is associated with increased risk of bleeding due to the need of lifelong indirect anticoagulant therapy. Therefore, biological heart valve prosthesis is an option of choice. Aim To estimate long-term results of aortic and mitral valve replacement with xenopericardial prosthesis «BioLAB». Methods 150 stented biological prostheses «BioLAB» were implanted into the aortic and mitral position in the Department of Emergency Surgery for Acquired Heart Disease in the period from January 1993 to December 2008. 50 stentless biological prostheses «BioLAB» were implanted in the aortic position in the period from January 2008 to December 2012. Results 1-, 5- and 10-years survival in the recipients of stented xenopericardial prostheses «BioLAB» implanted in aortic position was 91.1±2.9%, 85.3±6.1% and 85.3±6.1%, respectively. 5-, 10- and 15-years survival among those who received mitral valve replacement was 72.31%±5.56%, 55.18%±6.61%, and 22.77%±12.13%, respectively. There were no cases of redo surgeries for valve tissue degeneration among the recipients of stented and stentless aortic valve prostheses within the follow-up. 10-, 12- and 15-years freedom from mitral valve degeneration was 61.08±7.32%, 50.21±9.56%, and 43.6±10.65%. Conclusion Stented xenopericardial bioprostheses «BioLAB» implanted in the aortic position provide good and encouraging hemodynamic results in the long-term period time. There were no signs of tissue degeneration of the stented heart valves within the 10-years follow-up. Similar results were obtained for the stentless bioprosthesis within the 7-years follow-up. The period of 8.5 years after mitral valve replacement with «BioLAB» is critical for tissue degeneration of bioprosthesis.
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Pfensig, Sylvia, Sebastian Kaule, Robert Ott, Carolin Wüstenhagen, Michael Stiehm, Jonas Keiler, Andreas Wree, Niels Grabow, Klaus-Peter Schmitz, and Stefan Siewert. "Numerical simulation of a transcatheter aortic heart valve under application-related loading." Current Directions in Biomedical Engineering 4, no. 1 (September 1, 2018): 185–89. http://dx.doi.org/10.1515/cdbme-2018-0046.
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AbstractFor the treatment of severe symptomatic aortic valve stenosis, minimally invasive heart valve prostheses have more recently become the lifesaving solution for elderly patients with high operational risk and thus, are often implanted in patients with challenging aortic root configuration. A correct prosthesis deployment and stent adaption to the target region is essential to ensure optimal leaflet performance and long-term prosthesis function. The objective of this study was the development of a suitable in silico setup for structural numerical simulation of a transcatheter aortic valve (TAV) in different cases of clinical relevance. A transcatheter valve prosthesis comprising an unpressurized trileaflet heart valve and an adapted stent configuration was designed. An aortic root (AR) model was developed, based on microcomputed tomography of a native healthy specimen. Using the finite-element analysis (FEA), various loading cases including prosthesis biomechanics with valve opening and closing under physiological pressure ratios throughout a cardiac cycle, prosthesis crimping as well as crimping and release into the developed AR model were simulated. Hyperelastic constitutive law for polymeric leaflet material and superelasticity of shape memory alloys for the self-expanding Nitinol stent structure were implemented into the FEA setup. Calculated performance of the valve including the stent structure demonstrated enhanced leaflet opening and closing as a result of stent deformation and redirected loading. Crimping and subsequent release into the AR model as well as the stent adaption to the target region after expansion proved the suitability of the TAV design for percutaneous application. FEA represented a useful tool for numerical simulation of an entire minimally invasive heart valve prosthesis in relevant clinical scenarios.
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Chow, Simon CY, Alex PW Lee, Anthony MH Ho, Herman HM Chan, Malcolm J. Underwood, and Song Wan. "Redo tricuspid valve operation in patients with 1st-generation mitral prostheses." Asian Cardiovascular and Thoracic Annals 26, no. 7 (August 12, 2018): 524–28. http://dx.doi.org/10.1177/0218492318795545.
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Background In patients with remarkably enlarged cardiac chambers and history of implantation of older types of mitral valve prosthesis, the considerations for reoperative tricuspid valve surgery are not limited to the risks of sternal reentry but also include the dilemma of whether to carry out prophylactic replacement of the normal functioning but outdated prosthesis or leave it in situ. Methods We reviewed our surgical strategy and postoperative 5-year follow-up findings in two patients who underwent redo tricuspid surgery 3 to 4 decades after mechanical mitral valve replacement. Both patients presented with significant symptoms of progressive right heart failure due to severe tricuspid regurgitation, despite optimal medical therapy. Results We found the beating-heart approach to be an effective and safe method for redo tricuspid surgery. Both first-generation mitral mechanical prostheses were not replaced and have remained well functional upon the patients’ postoperative 5-year follow-up, respectively. Conclusion For patients with normal functioning first-generation mechanical mitral prostheses, whether to prophylactically replace the prosthesis should be based on an individualized risk-benefit analysis.
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Fukui, Miho, Vinayak N. Bapat, Santiago Garcia, Marshall W. Dworak, Go Hashimoto, Hirotomo Sato, Mario Gössl, et al. "Deformation of Transcatheter Aortic Valve Prostheses: Implications for Hypoattenuating Leaflet Thickening and Clinical Outcomes." Circulation 146, no. 6 (August 9, 2022): 480–93. http://dx.doi.org/10.1161/circulationaha.121.058339.
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Background: Although transcatheter aortic valve replacement (TAVR) therapy continues to grow, there have been concerns about the occurrence of hypoattenuating leaflet thickening (HALT), which may affect prosthesis function or durability. This study aimed to examine prosthesis frame factors and correlate their extent to the frequency of HALT and clinical outcomes. Methods: We prospectively examined 565 patients with cardiac computed tomography screening for HALT at 30 days after balloon-expandable SAPIEN3 and self-expanding EVOLUT TAVR. Deformation of the TAVR prostheses, asymmetric prosthesis leaflet expansion, prosthesis sinus volumes, and commissural alignment were analyzed on the postprocedural computed tomography. For descriptive purposes, an index of prosthesis deformation was calculated, with values >1.00 representing relative midsegment underexpansion. A time-to-event model was performed to evaluate the association of HALT with the clinical outcome. Results: Overall, HALT was present in 21% of SAPIEN3 patients and in 16% of EVOLUT patients at 30 days after TAVR. The occurrence of HALT was directly associated with greater prosthesis frame deformation ( P <0.001), worse asymmetry of the leaflets ( P <0.001), and smaller TAVR neosinus volumes ( P <0.001). These relations were present in both prosthetic types and in all of their size ranges (all P <0.05). In multivariable analyses that include clinical variables previously associated with HALT (eg, anticoagulant therapy), variables of TAVR prosthesis deformation remained predictive of HALT. Although HALT was not associated with changes in prosthetic hemodynamics, its presence was associated with the risk of mortality at 1 year, with respect to greater incidences of all-cause mortality (hazard ratio, 2.98 [95% CI, 1.57–5.63]; P =0.001), cardiac death (hazard ratio, 4.58 [95% CI, 1.81–11.6]; P =0.001), and a composite outcome of all-cause mortality and heart failure hospitalization (hazard ratio, 1.94 [95% CI, 1.14–3.30]; P =0.02) with adjustment for age, sex, and comorbidities. Conclusions: Nonuniform expansion of TAVR prostheses resulting in frame deformation, asymmetric leaflet, and smaller neosinus volume is related to occurrence of HALT in patients who undergo TAVR. These data may have implications for both prosthesis valve design and deployment techniques to improve clinical outcomes for these patients.
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Pfensig, Sylvia, Sebastian Kaule, Michael Sämann, Michael Stiehm, Niels Grabow, Klaus-Peter Schmitz, and Stefan Siewert. "Assessment of heart valve performance by finite-element design studies of polymeric leaflet-structures." Current Directions in Biomedical Engineering 3, no. 2 (September 7, 2017): 631–34. http://dx.doi.org/10.1515/cdbme-2017-0132.
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AbstractFor 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.
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Angelov, Hr, P. Simeonov, P. Krastev, F. Abedinov, J. Jorgova, and D. Trendafilova. "Balloon expandable vs. self-expandable transcatheter aortic valve prosthesis short-term results of retrospective study." Bulgarian Cardiology 28, no. 2 (June 20, 2022): 90–95. http://dx.doi.org/10.3897/bgcardio.28.e83164.
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Transcutaneous aortic valve implantation has been established as an effective method for the treatment of highgrade aortic stenosis in non-operative, high-risk for conventional surgery patients. According to the developed implantation technologies, the prostheses are divided into balloon-expandable valve prostheses (balloon-expandable valves, BEV) and self-expanding valve prostheses (self-expanding prostheses SEV). The two types of devices have different models for implantation, stratum architecture, cusps characteristics, leading to different hemodynamics, frequency of use and performance of normal prosthesis function. The research aims to monitor the short-term results, up to 1 month after discharge, in terms of mortality, the manifestation of heart failure, (para) prosthetic regurgitation, implantation of a pacemaker, and vascular complications. Materials and methods: the article presents a retrospective follow-up of a total of 230 high-risk for conventional cardiac surgery patients with high-grade aortic stenosis treated in a cardiology clinic at UMHAT St. Ekaterina Sofia until 2020, divided into two groups depending on the implanted type of prosthesis. Conclusions: The results obtained based on our experience prove the safety of new prostheses. When choosing between BEV and SEV, the best clinical outcome requires a good knowledge of the strengths and weaknesses of using medical devices with a personalized approach consistent with the clinical and anatomical characteristics of the patient.
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MOVILEANU, Ionela, Dan Octavian NISTOR, Leslie SIERAD, Klara BRINZANIUC, Codrut OPRITA, Marius Mihai HARPA, Terezia PREDA, et al. "Developing the Tissue Engineered Heart Valve – a Descriptive Hemodynamic and Ultrasound in Vitro Characterization Study of Heart Valves in a Bioreactor." Romanian Journal of Cardiology 31, no. 3 (September 24, 2021): 555–63. http://dx.doi.org/10.47803/rjc.2021.31.3.555.
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The inherent limitations of current heart valve substitutes create the premise for the Tissue Engineered Heart Valve (TEHV), considered the perfect substitute. We aimed to compare in vitro hemodynamic performances of our TEHV, the conventional prosthetic valve and similar porcine valves, by ultrasonography and geometry resulting in six valve models analysis. In a bioreactor, pulmonary and aortic physiology were replicated thus hemodynamic characteristics were tested. Using ultrasound, transvalvular pressure gradients and flow were measured and used to calculate their valvular functional area (VFA) and using a high-speed camera, the geometric peak opening area (GOA) was assessed. The obtained results were normalized to the diameter of the biological prosthesis in order to increase the measurement’s accuracy. The ultrasound revealed normal function of all valves and physiologic transvalvular pressure gradients. The TEHV scaffold revealed absence of laceration or dehiscence, and performances in accordance with the control prostheses. The GOA was facile to obtain and the normalized values proved to be greater than the calculated functional area in all analyzed cases and the peak opening areas resulted lesser for the aortic conditions for all six used valves prototypes. To our knowledge, this is the first study to use bioreactors, for in vitro evaluation of heart valves.
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DE GAETANO, FRANCESCO, PAOLA BAGNOLI, ADRIANO ZAFFORA, ANNA PANDOLFI, MARTA SERRANI, JACOB BRUBERT, JOANNA STASIAK, GEOFF D. MOGGRIDGE, and MARIA LAURA COSTANTINO. "A NEWLY DEVELOPED TRI-LEAFLET POLYMERIC HEART VALVE PROSTHESIS." Journal of Mechanics in Medicine and Biology 15, no. 02 (April 2015): 1540009. http://dx.doi.org/10.1142/s0219519415400096.
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The potential of polymeric heart valves (PHV) prostheses is to combine the hemodynamic performances of biological valves with the durability of mechanical valves. The aim of this work is to design and develop a new tri-leaflet prosthetic heart valve (HV) made from styrenic block copolymers. A computational finite element model was implemented to optimize the thickness of the leaflets, to improve PHV mechanical and hydrodynamic performances. Based on the model outcomes, 8 prototypes of the designed valve were produced and tested in vitro under continuous and pulsatile flow conditions, as prescribed by ISO 5840 Standard. A specially designed pulse duplicator allowed testing the PHVs at different flow rates and frequency conditions. All the PHVs met the requirements specified in ISO 5840 Standard in terms of both regurgitation and effective orifice area (EOA), demonstrating their potential as HV prostheses.
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Westaby, Stephen, Lognathen Balacumaraswami, Nikant Sabharwal, and Harald Becher. "The longest functioning heart valve prosthesis?" Journal of Thoracic and Cardiovascular Surgery 134, no. 4 (October 2007): 1049–50. http://dx.doi.org/10.1016/j.jtcvs.2007.05.051.
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Nair, Kalyani, C. V. Muraleedharan, and G. S. Bhuvaneshwar. "Developments in mechanical heart valve prosthesis." Sadhana 28, no. 3-4 (June 2003): 575–87. http://dx.doi.org/10.1007/bf02706448.
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Zielinska, M. "Fulminant thrombosis of mechanical mitral valve prosthesis." Heart 86, no. 5 (November 1, 2001): 16e—16. http://dx.doi.org/10.1136/heart.86.5.e16.
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Vladimirov, V. V., L. S. Kokov, A. I. Kovalyov, S. S. Niyazov, M. V. Parkhomenko, A. V. Redkoborody, N. V. Rubtsov, N. M. Bikbova, and R. Sh Muslimov. "The First Experience of Aortic Valve Repeated Replacement Using the “Valve in Valve” Technique in a Patient With Dysfunction of a Biological Prosthesis." Russian Sklifosovsky Journal "Emergency Medical Care" 10, no. 3 (November 19, 2021): 582–88. http://dx.doi.org/10.23934/2223-9022-2021-10-3-582-588.
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Introduction. Aortic valve replacement in cardiopulmonary bypass with suture fixation of the prosthesis is the “gold standard” in cardiac surgery. Currently, the frequency of use of heart valve bioprostheses is increasing in older patients. Despite all the advantages of using heart valve bioprostheses, this type of prosthesis has a major drawback - it is not durable. In most cases, the reason for the dysfunction of prostheses in the late postoperative period is early calcification of the prosthesis valves or their rupture due to degeneration. With the development of new “gentle” techniques for replacing heart valves, transcatheter aortic valve implantation was introduced into clinical practice. The use of transcatheter aortic valve implantation (TAVI) “valve in valve” for reoperations in older patients is of great interest, since in recent years the procedure has been widely used in clinical practice and shows promising data in patients with high surgical risk.Aim of study. Show first experience of using a technique «valve in valve» at N.V. Sklifosovsky Research Institute for Emergency Medicine.Material and methods. The results of surgical treatment of a patient with aortic valve bioprosthesis dysfunction using the TAVI “valve in valve” technique are presented.Results. The use of the TAVI “valve in valve” method made it possible to perform reprosthetics of the aortic valve (AV) from a transfemoral approach, not to increase the volume of intervention during reoperation, to avoid trauma to the structures of the heart and nearby tissues when accessing the AV in a patient with a high surgical risk.Conclusion. The use of the TAVI “valve in valve” method in cardiac surgery makes it possible to achieve good immediate and long-term results when it is necessary to replace the AV in patients with a high surgical risk.
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Chowdhury, Ujjwal Kumar, Niwin George, Lakshmi Kumari Sankhyan, Shikha Goja, Shweta Sharma, Niraj Nirmal Pandey, Srikant Sharma, and Shweta Sharma. "Redo Mitral Valve Replacement using St. Jude Medical Mechanical Prostheses in a Patient with Degenerated Mitral Perimount Bioprosthesis: A Video Presentation." Clinical Cardiology and Cardiovascular Interventions 4, no. 17 (November 15, 2021): 01–04. http://dx.doi.org/10.31579/2641-0419/223.
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Current consensus guidelines of the American Heart Association and European Society of Cardiology, uniformly recommend either type of prosthetic mitral valve for patients aged 60 to 70 years, and mechanical prosthesis for patients less than 60 years.
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Supadevi. S, K. Vijaykumar, Supasakthi. S, and Manimozhian. N. "Comparative Morphological and Morphometrical Analysis of Atrio-Ventricular Valves of Human and Porcine." International Journal of Anatomy and Research 11, no. 1 (February 26, 2023): 8559–63. http://dx.doi.org/10.16965/ijar.2022.287.
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There is increased incidence of valvular heart diseases in recent years due to life style modifications. The mortality rates in valvular diseases are kept in pace using various modalities of treatments. One such lifesaving treatment is valve replacement surgeries. These are done by using mechanical valve prosthesis or tissue grafts. The tissue valves prosthesis, harvested from porcine heart are called as xenograft and are increasingly used in valve repair and replacement surgeries. In the present scenario, there is a smaller number of systematically analysed literatures available on the comparative anatomy of human and porcine heart valves. Hence this study was carried out to acquire knowledge and to put forth some points to future research works on heart valves. In this study, 20 formalin fixed porcine and human hearts were procured from slaughter house and cadavers respectively. The morphology and morphometry of tricuspid valve and mitral valve was observed and analysed using spss software 20 version. All the dependent variables were compared using student t test and independent sample test. The results were tabulated and compared. It was observed that the tricuspid and the mitral valve of the porcine resembles the corresponding human heart valves in morphology and morphometry and their values were coinciding to their maximum. The porcine valve resembles human heart valves in morphology and it can be used in designing valve substitutes in replacement surgeries. Porcine valve can also be used as bio-prosthesis by matching the morphometry and by reducing the geometrical difference to their minimum by using any interventional radiology. KEY WORDS: Tissue Graft, Porcine, Tricuspid Valve, Mitral Valve, Morphology And Morphometry.
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Cobo, Fernando, Elizabeth Calatrava, and José María Navarro-Marí. "Early Prosthetic Valve Endocarditis Due to Finegoldia magna." Microbiology Insights 12 (January 2019): 117863611987664. http://dx.doi.org/10.1177/1178636119876640.
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Finegoldia magna is a Gram-positive anaerobic cocci frequently reported in human diseases. We report a rare case of mechanical prosthetic endocarditis due to this microorganism in a patient with heart disease. A 50-year-old man with prosthetic mitral and aortic valve presented with pericardial effusion, cardiac tamponade, and multiorgan dysfunction. Anaerobic blood cultures yielded a positive result, allowing further identification as F magna by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The patient suffered replacement of mechanical mitral prosthesis by a new mechanical prosthesis, growing also F magna in the valvular culture. The isolate was identified as F magna by 16S ribosomal RNA sequence analysis. As a complication, a convulsive episode occurred, but a positive outcome was finally observed.
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Barbarash, L., I. Kudryavtsev, N. Rutkovskaya, and A. Golovkin. "T Cell Response in Patients with Implanted Biological and Mechanical Prosthetic Heart Valves." Mediators of Inflammation 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/1937564.
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The study was aimed at assessing T cell subsets of peripheral blood from recipients of long-term functioning (more than 60 months) biological and mechanical heart valve prostheses. The absolute and relative number of CD4 and CD8 T cell subsets was analyzed: naïve (N, CD45RA+CD62L+), central memory (CM, CD45RA−CD62L+), effector memory (EM, CD45RA−CD62L−), and terminally differentiated CD45RA-positive effector memory (TEMRA, CD45RA+CD62L−) in 25 persons with biological and 7 with mechanical prosthesis compared with 48 apparently healthy volunteers. The relative and absolute number of central memory and naïve CD3+CD8+in patients with biological prosthesis was decreased (p<0.001). Meanwhile the number of CD45RA+CD62L−CD3+CD8+and CD3+CD4+was increased (p<0.001). Patients with mechanical prosthesis had increased absolute and relative number of CD45RA+CD62L−CD3+CD8+cells (p=0.006). Also the relative number of CD3+CD4+cells was reduced (p=0.04). We assume that altered composition of T cell subsets points at development of xenograft rejection reaction against both mechanical and biological heart valve prostheses.
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Essa, Amr, Toufik Haddad, and Terrence Slattery. "Successful Fibrinolytic Therapy in a Challenging Obstructive Prosthetic Mitral Valve Thrombosis." Journal of Investigative Medicine High Impact Case Reports 8 (January 2020): 232470962092107. http://dx.doi.org/10.1177/2324709620921078.
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Prosthetic valve thrombosis is a rare and severe complication of the mechanical prosthetic valve. Management can be challenging due to varying clinical presentation, overlapping features of differential diagnosis, and lack of randomized controlled trials on the therapeutic options. In this article, we report the case of a patient with a mechanical prosthetic mitral valve presented with symptoms of heart failure, and an echocardiography showing increased mean pressure gradient across the prosthesis along with a fixed posterior leaflet and a partially restricted anterior leaflet with no visible mass. That raised the concern for an obstructed prosthesis. After multimodality imaging and multidisciplinary team discussions, prosthetic valve thrombosis diagnosis was favored over other different diagnoses that included but not limited to pannus ingrowth. Fibrinolytic therapy was administrated, and the patient was discharged on optimal anticoagulation. Repeated echocardiography a month later showed normal mean gradient and normal functioning prosthetic mitral valve without the need for repeat mitral valve surgery.
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Majdevac, Slavica, Andrej Preveden, Nina Dracina, Nikola Bakic, Mihaela Preveden, and Stamenko Susak. "Prosthetic heart valve thrombosis - a headache for the heart team: A case report." Medical review 76, no. 3-4 (2023): 112–16. http://dx.doi.org/10.2298/mpns2304112m.
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Introduction. Prosthetic valve thrombosis is usually a subacute or chronic condition, although it may also present with a fresh thrombus. It occurs in two forms: obstructive and non-obstructive thrombosis. Case Report. We present a case of a female patient who underwent mitral valve replacement with mechanical prosthesis due to severe mitral stenosis. The postoperative course was uneventful and the patient was discharged on vitamin K antagonist therapy with international normalized ratio target 3.0. Five months later, the patient was admitted with severe shortness of breath and signs of acute heart failure. International normalized ratio at that moment was 2.3. Transthoracic echocardiography indicated severely raised gradient across the prosthetic valve and mechanical valve malfunction was suspected. Cinefluoroscopy showed that one of the prosthetic valve leaflets was completely immobile. Transesophageal echocardiography definitely confirmed thrombosis of the prosthetic valve with large multiple thrombi that completely fixed one leaflet in closed position, and partially limited the motion amplitude of the other leaflet. There were thrombi floating between the left ventricle and left atrium. Thrombectomy of the prosthetic valve was performed, which was sufficient for the complete restoration of the mechanical valve function. The vitamin K antagonist dosage was carefully up-titrated in order to reach and maintain the target international normalized ratio of 3.0. Conclusion. Prosthetic valve thrombosis is a serious and life-threatening condition that requires urgent management. Coordination and cooperation of the whole heart team is necessary for optimal choice of treatment, which primarily includes surgery or fibrinolysis.
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El Midany, Ashraf AH, Ezzeldin A. Mostafa, Tamer Hikal, Mostafa G. Elbarbary, Ayman Doghish, Ramy Khorshid, Basem M. Abdelgawad, et al. "Incidence and predictors of mismatch after mechanical mitral valve replacement." Asian Cardiovascular and Thoracic Annals 27, no. 7 (August 7, 2019): 535–41. http://dx.doi.org/10.1177/0218492319869560.
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Background Patient-prosthesis mismatch after mitral valve replacement has an unfavorable postoperative hemodynamic outcome, which underlines the importance of identifying and preventing prosthesis- and patient-related risk factors. This study was conducted to determine the incidence and identify possible predictors of patient-prosthesis mismatch. Methods A prospective study was conducted on 715 patients with a mean age of 42 ± 11 years who underwent mechanical mitral valve replacement between 2013 and 2017. The effective orifice area of the prostheses was estimated by the continuity equation, and a mismatch was defined as an effective orifice area index ≤1.2 cm2·m−2. The mean clinical and echocardiographic follow-up was 26.74 ± 11.58 months. Multivariate regression analysis was performed to identify predictors of patient-prosthesis mismatch. Results Patient-prosthesis mismatch was detected in 382 (53.4%) patients. A small mechanical prosthesis (<27 mm) was inserted in 54.3%. Mortality during follow-up was 9% (65 patients). Patient-prosthesis mismatch was identified in patients with preoperative rheumatic mitral valve pathology, associated tricuspid regurgitation, higher New York Heart Association class, preoperative atrial fibrillation, mitral stenosis, and small preoperative left ventricular dimensions. Multivariate analysis identified mitral stenosis, preoperative atrial fibrillation, and small postoperative left ventricular end-diastolic dimension as risk factors for patient-prosthesis mismatch. Conclusion Patient-prosthesis mismatch is a common sequela after mechanical mitral valve replacement. Identification of predictors of patient-prosthesis mismatch can help so that a preoperative strategy can be implemented to avoid its occurrence.
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Zhang, Yunyi, and Shuhua Luo. "Thrombosis of Prosthetic Tricuspid Valve During Veno-Arterial Extracorporeal Membrane Oxygenation Support: A Case Report." International Journal of Anesthesia and Clinical Medicine 12, no. 1 (February 20, 2024): 11–14. http://dx.doi.org/10.11648/j.ijacm.20241201.13.
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Extracorporeal membrane oxygenation (ECMO) is frequently used for severe postcardiotomy cardiogenic shock in patients with bioprosthetic valves. Acute prosthetic valve thrombosis (PVT) is a rare complication after valve replacement surgery and significantly increases morbidity and mortality. Patients who develop PVT on ECMO could significantly influence the long-term durability of the bioprosthetic valves. However, previous studies only analyzed risk factor and treatment of the mitral valve thrombosis during ECMO support. The mechanism of thrombosis on the tricuspid valve was still unknown. Here we describe the symptoms and treatment of a valve replacement patient who developed bioprosthetic tricuspid valve thrombosis during veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Meanwhile, the patient’s mechanical prosthetic mitral valve functioned normally. An emergency re-do tricuspid prosthesis replacement was performed, and the patient finally developed the successful decannulation. At 6 months follow-up, the patient showed asymptomatic and had a reasonable quality of life. The pathophysiology of tricuspid valve thrombosis may be different from the left heart. Our case highlights that the risk of thrombosis associated with a prosthesis in the tricuspid position can be even higher in the setting of VA-ECMO support. In such patients, promoting forward blood flow across the prosthesis and improving levels of anticoagulation may be particularly important.
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Park, Sung Jun, You Jung Ok, Ho Jin Kim, Ye-Jee Kim, Seonok Kim, Jung-Min Ahn, Dae-Hee Kim, Jae-Sung Choi, and Joon Bum Kim. "Evaluating Reference Ages for Selecting Prosthesis Types for Heart Valve Replacement in Korea." JAMA Network Open 6, no. 5 (May 22, 2023): e2314671. http://dx.doi.org/10.1001/jamanetworkopen.2023.14671.
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ImportanceAlthough a patient’s age may be the only objective figure that can be used as a reference indicator in selecting the type of prosthesis in heart valve surgery, different clinical guidelines use different age criteria.ObjectiveTo explore the age-associated survival-hazard functions associated with prosthesis type in aortic valve replacement (AVR) and mitral valve replacement (MVR).Design, Setting, and ParticipantsThis cohort study compared the long-term outcomes associated with mechanical and biologic prostheses in AVR and MVR according to recipient’s age using a nationwide administrative data from the Korean National Health Insurance Service. To reduce the potential treatment-selection bias between mechanical and biologic prostheses, the inverse-probability-of-treatment-weighting method was used. Participants included patients who underwent AVR or MVR in Korea between 2003 and 2018. Statistical analysis was performed between March 2022 and March 2023.ExposuresAVR, MVR, or both AVR and MVR with mechanical or biologic prosthesis.Main Outcomes and MeasuresThe primary end point was all-cause mortality after receiving prosthetic valves. The secondary end points were the valve-related events, including the incidence of reoperation, systemic thromboembolism, and major bleeding.ResultsOf the total of 24 347 patients (mean [SD] age, 62.5 [7.3] years; 11 947 [49.1%] men) included in this study, 11 993 received AVR, 8911 received MVR, and 3470 received both AVR and MVR simultaneously. Following AVR, bioprosthesis was associated with significantly greater risks of mortality than mechanical prosthesis in patients younger than 55 years (adjusted hazard ratio [aHR], 2.18; 95% CI, 1.32-3.63; P = .002) and in those aged 55 to 64 years (aHR, 1.29; 95% CI, 1.02-1.63; P = .04), but the risk of mortality reversed in patients aged 65 years or older (aHR, 0.77; 95% CI, 0.66-0.90; P = .001). For MVR, the risk of mortality was also greater with bioprosthesis in patients aged 55 to 69 years (aHR, 1.22; 95% CI, 1.04-1.44; P = .02), but there was no difference for patients aged 70 years or older (aHR, 1.06; 95% CI, 0.79-1.42; P = .69). The risk of reoperation was consistently higher with bioprosthesis, regardless of valve position, in all age strata (eg, MVR among patients aged 55-69 years: aHR, 7.75; 95% CI, 5.14-11.69; P &lt; .001); however, the risks of thromboembolism and bleeding were higher in patients aged 65 years and older after mechanical AVR (thromboembolism: aHR, 0.55; 95% CI, 0.41-0.73; P &lt; .001; bleeding: aHR, 0.39; 95% CI, 0.25-0.60; P &lt; .001), with no differences after MVR in any age strata.Conclusions and RelevanceIn this nationwide cohort study, the long-term survival benefit associated with mechanical prosthesis vs bioprosthesis persisted until age 65 years in AVR and age 70 years in MVR.
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Ovcharenko, E. A., K. Yu Klyshnikov, A. N. Stasev, A. V. Evtushenko, I. K. Khalivopulo, D. V. Borisenko, T. V. Glushkova, et al. "Experience in the development of a system for repeated prosthetic heart valves." Сибирский научный медицинский журнал 43, no. 4 (August 30, 2023): 78–90. http://dx.doi.org/10.18699/ssmj20230408.
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The failure of heart valve bioprostheses, requiring repeated intervention to replace them, is a serious drawback that narrows the scope of such devices. The present study demonstrates the experimental investigation of a medical device designed to partially solve the problem of repeated interventions on heart valves, primarily with an emphasis on reducing the duration and trauma of such procedures due to the sutureless balloon implantation method of the «valvein- valve» method.Material and methods. The paper presents a series of in silico, in vitro and in vivo experiments to evaluate various aspects of the device under development. Numerical modeling of the final shape setting to the supporting frame of the heart valve prosthesis to select the most promising concept for prototyping was carried out in the Abaqus/CAE (Dassault Systèmes, France) based on the finite element method. The selected optimal support frame model was prototyped in the form of a series of prosthesis samples of four standard sizes for hydrodynamic studies of quantitative characteristics in vitro. The study was carried out in the Vivitro Labs unit (Vivitro Labs, Canada), imitating the physiological mode of the heart, the prostheses were examined for the mitral position. The developed prototypes of the device were supplemented with related products, an implant holder and a balloon catheter, after which the proposed method of sutureless fixation was validated in an in vitro implantation procedure on a bovine heart model and a series of in vivo (n = 3) chronic experiments on animals.Results. In the course of numerical simulation, it was shown that in Model No. 3 of the supporting frame of the prosthesis, the smallest stresses occur – with an amplitude of up to 490 MPa. For other concepts (Models No. 1 and No. 2), this indicator was significantly higher, 543 and 514 MPa, respectively. Prototypes obtained on the basis of the selected shape of the support frame demonstrated satisfactory hydrodynamic characteristics: effective hole area 190-261 mm2, regurgitation volume 6–9 ml/cycle, average transprosthetic gradient 4.4–6.4 mmHg, depending on size. The study of the technology of sutureless balloon implantation in an in vitro model of the heart and the subsequent chronic experiment on sheep confirmed the main idea of the system – the possibility of a significant reduction in the duration of repeated prosthetics. It has been shown that the time of suture implantation of the “classic” frame prosthesis of the mitral valve is 23–29 minutes, with a total access time of 41–52 minutes. When implanting the experimental device, the sutureless prosthesis itself took 4–6 minutes, access time 24–29 minutes. At the same time, one-month results of an echocardiographic study of the operation of the prosthesis demonstrated satisfactory hemodynamics.Conclusions. This work demonstrates a consistent series of tests of the system being developed for repeated heart valve replacement, which substantiates some design solutions, confirms the effectiveness and viability of the chosen approach to sutureless minimally invasive implantation.
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Srivastava, Ashok K., Ashok K. Gupta, Arvind V. Singh, and Tanveer Husain. "Effect of Oral Anticoagulant during Pregnancy with Prosthetic Heart Valve." Asian Cardiovascular and Thoracic Annals 10, no. 4 (December 2002): 306–9. http://dx.doi.org/10.1177/021849230201000405.
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This retrospective study aimed to evaluate the risks and outcome of oral anticoagulant use during pregnancy in women with prosthetic heart valves. Between December 1989 and November 1998, 192 females of childbearing age underwent heart valve replacement with a mechanical prosthesis. There were 37 pregnancies in 30 patients during follow-up. Pregnancy was terminated on medical grounds in 5 cases, there were 2 (6%) spontaneous abortions, and 1 (3%) premature birth of a normal baby who died 24 hours later due to asphyxia. The other 29 pregnancies (91%) went to full term and the mothers continued taking oral anticoagulants until a week before the expected date of delivery, then switched to heparin. There was no thromboembolism, valve thrombosis, or maternal mortality. Three babies (10%) had a skeletal deformity: nasal hypoplasia in all 3, with cleft pinna in 1. Continuation of oral anticoagulants during pregnancy provided adequate protection against thromboembolism and valve thrombosis, but the risks of fetal abnormalities and premature delivery should be explained to women of childbearing age with a mechanical valve prosthesis.
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Vidyasagar, K. E. Ch, and Ravi Varma N. "Design and Development of Caged Ball Heart Valve Using Solid Works." International Journal of Systems Applications, Engineering & Development 16 (March 10, 2022): 34–37. http://dx.doi.org/10.46300/91015.2022.16.6.
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Currently, over 2, 90,000 heart valve surgeries are performed worldwide annually and that number is estimated to triple by 2050. Even though patients with prosthetic valves lead a life relatively free from symptoms, problems like physiological complications and valve failure are significant. To date, all mechanical heart valves are plagued with complications associated with hemolysis and coagulation. These complications are believed to be associated with non-physiological blood flow patterns in the vicinity of the artificial heart valves. The geometry of the valve prosthesis with respect to the mitral valve annulus may significantly affect the flow dynamics in the human heart. It is thus essential to assess the hemodynamics of mitral prosthetic caged ball valve to improve the design of the device. This research work presents a 3D model of the left human heart with optimized mitral caged ball valve engineered by a computational tool (SolidWorks 2009). The performance of the valve like hemodynamics across the valve, stress analysis and physical properties like mass, surface area, etc. is assessed virtually. This limits the need to perform extensive, costly and timeconsuming in-vitro and animal tests. Thus optimization of the caged ball heart valve design facilitates reduction of flow-induced thrombogenicity and reduces the need for post-implant anticoagulants.
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Dalal, Dhaval, and Vijaykumar Gawali. "Long-term thromboprophylaxis in metallic aortic valve prosthesis using oral nattokinase-A case report." Indian Journal of Pharmacy and Pharmacology 10, no. 1 (March 15, 2023): 41–44. http://dx.doi.org/10.18231/j.ijpp.2023.011.
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Oral anticoagulation with a vitamin K antagonist like warfarin is the standard of care for thromboprophylaxis after cardiac valve replacement. However warfarin requires strict monitoring of INR to avoid bleeding.Bleeding is a major concern with warfarin, particularly in those at high risk. Nattokinase is an enzyme obtained from natto, a cheese-like food made of soybeans fermented with Bacillus subtilis, which has been consumed as a traditional food in certain Asian countries for more than 2000 years.Recent research has demonstrated that nattokinase has potent fibrinolytic activity and antithrombotic action. We present a case of a 37-year-old male who had undergone aortic valve replacement using a metallic prosthetic valve for rheumatic heart disease associated severe aortic regurgitation and has been maintained on oral nattokinase therapy for prophylaxis against thromboembolic complications post cardiac wall replacement since the last 12 years.This case highlights the role of oral nattokinase for thromboprophylaxis in valve prosthesis and other prothrombotic states. This case report presents the first documented case where oral nattokinase has been successfully used for long-term thromboprophylaxis in metallic aortic valve prosthesis.: We present a case of a 37-year-old male who had undergone aortic valve replacement using a metallic prosthetic valve for rheumatic heart disease associated severe aortic regurgitation and has been maintained on oral nattokinase therapy for prophylaxis against thromboembolic complications post cardiac wall replacement since the last 12 years.This case highlights the role of oral nattokinase for thromboprophylaxis in valve prosthesis and other prothrombotic states. This case report presents the first documented case where oral nattokinase has been successfully used for long-term thromboprophylaxis in metallic aortic valve prosthesis.
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Petlin, K. A., E. A. Kosovskikh, E. V. Lelik, and B. N. Kozlov. "Comparative analysis of hemodynamic characteristics of the biological xenogenic pericardial prosthesis MEDINGE-BIO with “easy change” system and the xenogenic aortic prosthesis Hancock II after aortic valve replacement." Russian Journal of Cardiology 26, no. 8 (September 4, 2021): 4533. http://dx.doi.org/10.15829/1560-4071-2021-4533.
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Aim. To compare the outcomes of aortic valve replacement using the xenogenic aortic prosthesis Hancock II and the novel Russian xenogenic pericardial prosthesis MEDINGE-BIO.Material and methods. The study included patients operated on for aortic stenosis in the cardiac surgery department № 1 of the Cardiology Research Institute (Tomsk National Research Medical Center). All patients were divided into two groups. The first group included 54 patients with Hancock II prostheses, the second — 91 patients with MEDINGE-BIO prostheses. Hemodynamic characteristics of heart valves were assessed by echocardiography before surgery and before discharge (on average 10 days after surgery).Results. When comparing hemodynamic parameters before and after surgery, significant differences between the groups were not obtained. The average pressure gradient after surgery using Hancock II and MEDINGE-BIO prosthesis was 21,6±7,9 and 17,9±5,6 mm Hg, respectively (p=0,05).Conclusion. The comparative analysis showed that the novel biological prosthesis MEDINGE-BIO has comparable hemodynamic characteristics with the well-known aortic prosthesis Hancock II.
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Belluschi, Igor, Nicola Buzzatti, Alessandro Castiglioni, Michele De Bonis, Francesco Maisano, and Ottavio Alfieri. "Aortic and mitral bioprosthetic valve dysfunction: surgical or percutaneous solutions?" European Heart Journal Supplements 23, Supplement_E (October 1, 2021): E6—E12. http://dx.doi.org/10.1093/eurheartj/suab083.
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Abstract In the last years, there has been a trend to prefer biological prostheses, especially among young patients, with the aim to avoid anticoagulant treatment. Surgical tissue valves have so far demonstrated their solid long-term durability. However, younger age has been identified as one of the main risk factors for developing structural valve deterioration (SVD). As a consequence, the proportion of subjects at risk for valve dysfunction will constantly rise in the near future. However, while surgical reintervention has always been considered the gold standard for treatment of prosthesis deterioration, the introduction of transcatheter heart valves could offer new therapeutical options, particularly among high-risk patients, aiming a second less invasive chance. The recent standardization of valve durability definitions will soon allow a more comprehensive understanding of the mechanism underlying SVD and guide the choice of prosthesis for patients needing valve replacement.
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Shilko, S. V., S. P. Salivonchik, V. F. Hizhenok, V. V. Anichkin, and Y. M. Pleskachevsky. "THE BIOMECHANICAL ANALUSIS OF ARTIFICIAL DISK-CONSTRUCTION HEART VALVE FUNCTIONINS." Health and Ecology Issues 1, no. 2 (February 15, 2004): 131–40. http://dx.doi.org/10.51523/2708-6011.2004-1-2-26.
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The valve functions of heart (in norm and pathological state) and hemodynamic characteristics of mechanical prosthetic cardiac valves influencing hemolysis and blood coagulation have been investigated. The computer and physical models of the disc cardiac valve implant have been constructed. The analysis of blood velocity and pressure at direct and inverse blood flows has shown better characteristics of butterfly valves. An advantage of this approach is in thorough description of blood flow assisting in determination of turbulence and depression zones for different size, curvature and ultimate opening angle of the leaves. This minimises hydraulic resistance, thrombus formation and hemolysis thus preserving high reliability of valve closing. A design of the valve prosthesis aimed at improving valve functions by swirling the blood flow is discussed.
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Ovcharenko, E. A., P. S. Onishchenko, and K. Yu Klyshnikov. "Optimization of the biological valve appliance prosthetic heart valve." Complex Issues of Cardiovascular Diseases 11, no. 2 (April 5, 2022): 39–48. http://dx.doi.org/10.17802/2306-1278-2022-11-2-39-48.
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Highlights. With the use of numerical optimization algorithms, it is possible to qualitatively improve the performance (closing) of the leaflet apparatus of the heart valve prosthesis. Changing the length of the free edge of the lealflet of the prosthesis does not reduce the von Misess stress amplitude and does not change the nature of its distribution on the diagrams.Aim. Numerical study of the stress-strain state of a clinical heart valve prosthesis from the point of view of the impact of physiological loads and determination of ways to optimize the geometry of the biological leaflet apparatus.Methods. The object of study was a three-dimensional model of the UniLine (NeoCor, Russia) clinical prosthesis of the heart valve, size 23 mm, as well as four modifications focused on changing the length of the free edge. The study was carried out using the finite element method with imitation of the full cycle of operation of the leaflet apparatus under physiological conditions (pressure, heart rate). The parameters for the analysis were the qualitative and quantitative characteristics of the stress-strain state of the work of the five studied geometries.Results. It is shown that high stress areas are concentrated in two zones peripheral and free edges, regardless of the geometry. However, quantitatively, the von Mises stress amplitudes differed between the studied models. For example, the leaf shape, conventionally designated as “–10” degrees, demonstrated the smallest amplitude of this indicator relative to the original unmodified leaf model, thus reducing by a maximum of 18.8%. However, for the closed state, this model, on the contrary, showed an increase in the voltage index relative to the initial one by 8.3%. Other modification options showed similar trends.Conclusion. It is shown that despite the initial premise for optimizing the leaflet apparatus – reducing the length of the free edge and eliminating deformations of the closed state, the proposed geometry options did not significantly change the stress distribution map in the material, and also did not allow to significantly reduce the amplitudes of this parameter. Presumably, options for modifying the geometry and/or properties (rigidity, mobility) of another important component of the bioprosthesis, the support frame, which, in addition to the bearing function, provides damping of the hydrodynamic impact on the leaf due to some of its mobility, may become more promising.