scholarly journals POLYMERIC HEART VALVE PROSTHESES: CONDITION AND PERSPECTIVES

2018 ◽  
Vol 20 (2) ◽  
pp. 100-111
Author(s):  
M. A. Rezvova ◽  
E. A. Ovcharenko
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Three Dimensional ◽  
High Strength ◽  
Valve Body ◽  
Nanocomposite Polymer ◽  
Valve Stem ◽  
Valve Prostheses ◽  
Number Of Publications

The idea of creating a polymer heart valve, which has high strength and biocompatibility, occurs in the 60’s. Since then, many polymer compounds have been investigated, but no solution has been found for this problem. In recent years, in connection with the development of technologies for the synthesis of high-molecular compounds, new polymers have appeared that can solve this problem, as evidenced by a number of publications describing experimental and clinical data. Nevertheless, the search for a polymer for the valve stem of the valvular valve body does not lose its relevance due to the defi ciencies studied and the lack of evidence confi rming the long-term safety of such products. This review presents the fi rst results of a study of polymer heart valves prostheses based on a nanocomposite polymer from polyhedral oligomeric nanoparticles of silicosioxane and polycarbonate urethane polymer POSS-PCU, polystyrene block-isobutylene-block-styrene SIBS, PTFE polytetrafl uoroethylene, copolymers and composites based on olefi n polymers series and polyesters, the idea of creating a material with a given three-dimensional microarchitecture that determines the anisotropy and the necessary mechanical properties.

Identification of mechanical prosthetic heart valves based on distinctive cinefluoroscopic and echocardiographic markers

2019 ◽  
Vol 42 (11) ◽  
pp. 603-610 ◽  
Author(s):  
Macit Kalçık ◽  
Ahmet Güner ◽  
Mahmut Yesin ◽  
Emrah Bayam ◽  
Semih Kalkan ◽  
...  
Keyword(s):  
Transesophageal Echocardiography ◽  
Heart Valve ◽  
Prosthetic Valve ◽  
Heart Valves ◽  
Large Body ◽  
Mechanical Heart Valve ◽  
Three Dimensional ◽  
Prosthetic Heart Valves ◽  
Mechanical Prostheses ◽  
Valve Prostheses

The past 65 years have witnessed remarkable progress in the development of safe, hemodynamically favorable mechanical heart valves. Today, there are a large number and variety of prostheses in use and many prostheses have been used for a while and then discontinued. When patients lack reliable information about their heart valve prostheses, identification of valve model becomes difficult even for specialized physicians in this area. A combination of cinefluoroscopy and echocardiography makes it possible to provide accurate and detailed information regarding identification of prosthetic valve models. Fluoroscopic examination is a useful technique to evaluate patients following mechanical heart valve replacement. However, transthoracic echocardiography and transesophageal echocardiography have almost replaced cinefluoroscopy in the evaluation of prosthetic heart valves. Especially, real-time three-dimensional transesophageal echocardiography provides distinctive images of prosthetic heart valves, particularly for those in the mitral position. A large body of literature has been published to familiarize physicians with the radiological appearance of numerous mechanical prostheses. However, there is a lack of data regarding the identification of prosthetic valve models based on echocardiographic appearance. In this review, we aimed to describe distinctive echocardiographic and cinefluoroscopic markers for identifying the type and brand of several commonly used mechanical prosthetic heart valves.

Large Displacement Flexural Properties of Tissue Engineered Heart Valve Scaffolds

2000 ◽  
Author(s):  
Michael S. Sacks ◽  
Sanjay Kaushal ◽  
John E. Mayer
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Critical Test ◽  
Bioprosthetic Heart Valves ◽  
Property Evaluation ◽  
Fundamental Information ◽  
Tissue Engineered Heart Valve ◽  
Valve Prostheses ◽  
Tissue Engineered Heart Valves

Abstract The need for improved heart valve prostheses is especially critical in pediatric applications, where growth and remodeling are essential. Tissue engineered heart valves (TEHV) have functioned in the pulmonary circulation of growing lambs for up to four months [1], and thus can potentially overcome limitations of current bioprosthetic heart valves. Despite these promising results, significant questions remain. In particular, the role of scaffold mechanical properties in optimal extra-cellular matrix development, as well as TEHV durability, are largely unexplored. We have previously demonstrated flexure testing as a sensitive and critical test for BHV tissue mechanical property evaluation [2]. The following study was conducted to determine the feasibility of using this technique to provide fundamental information required for optimizing TEHV scaffold designs.

Regurgitant Commissure Flow Through a Closed Polymeric Heart Valve

2010 ◽  
Author(s):  
Scott C. Corbett ◽  
Hamid N.-Hashemi ◽  
Ahmet U. Coskun
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Structural Changes ◽  
Patient Survival ◽  
Improve Patient Survival ◽  
Flow Disturbances ◽  
Limited Life ◽  
Flow Through ◽  
Valve Prostheses ◽  
Improve Patient

While heart valve prostheses have been used successfully since 1960, outcomes are far from ideal. The underlying problem with bioprostheses is a limited life from structural changes such as calcification and leaflet wear, leading to valve failure. The underlying problem with mechanical heart valves is the presence of flow disturbances which necessitate anticoagulation. A polyurethane valve has the potential to improve upon the shortcomings of existing valves and ultimately improve patient survival.

Characterization of a Novel Polymeric Trileaflet Heart Valve Prosthesis

2009 ◽  
Author(s):  
Scott C. Corbett ◽  
Neil Verma ◽  
Parnian Boloori Zadeh ◽  
Ahmet U. Coskun ◽  
Hamid N.-Hashemi
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Structural Changes ◽  
Survival Rates ◽  
Valve Prosthesis ◽  
Improve Patient Survival ◽  
Limited Life ◽  
Valve Prostheses ◽  
Improve Patient

While heart valve prostheses have been used successfully since 1960, 10-year survival rates still range from 37–58% [1]. The underlying problem with bioprostheses is a limited life from structural changes such as calcification and leaflet wear, leading to valve failure [2]. Biological tissue fixation and methods used to mount the tissue to a supporting stent can be blamed for this shortcoming. The underlying problem with mechanical heart valves is the presence of a centrally located leaflet, or occluder. It propagates high velocity jets, turbulence and areas of stagnation: the disturbances which necessitate anticoagulation [3]. A polyurethane valve has the potential to improve upon the shortcomings of existing valves and ultimately improve patient survival.

scholarly journals Stereoscopic PIV of Steady Flow Through a Bileaflet Mechanical Heart Valve

2008 ◽  
Author(s):  
C. Hutchison ◽  
P. E. Sullivan ◽  
C. R. Ethier
Keyword(s):  
Steady Flow ◽  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Shear Stresses ◽  
Stereoscopic Piv ◽  
Bileaflet Mechanical Heart Valve ◽  
Component Particle

Each year over 180,000 mechanical heart valves are implanted worldwide, with the bileaflet mechanical heart valve (BiMHV) accounting for approximately 85% of all valve replacements [1,2]. Although much improved from previous valve designs, aortic BiMHV design is far from ideal, and serious complications such as thromboembolism and hemolysis often result. Hemolysis and platelet activation are thought to be caused by turbulent Reynolds shear stresses in the flow [1]. Numerous previous studies have examined aortic BiMHV flow using LDA and two component Particle Image Velocimetry (PIV), and have shown the flow to be complex and three-dimensional [3,4]. Stereoscopic PIV (SPIV) can obtain all three velocity components on a flow plane, and hence has the potential to provide better understanding of three dimensional flow characteristics. The objective of the current study was to use SPIV to measure steady flow, including turbulence properties, downstream of a BiMHV in a modeled aorta. The resulting dataset will be useful for CFD model validation, and the intent is to make it publicly available.

Tissue Engineering of Heart Valves: Formation of a Three-Dimensional Tissue Using Porcine Heart Valve Cells

ASAIO Journal ◽  
2002 ◽  
Vol 48 (6) ◽  
pp. 586-591 ◽  
Author(s):  
Markus Rothenburger ◽  
Wolfgang Völker ◽  
Peter Vischer ◽  
Elmar Berendes ◽  
Birgit Glasmacher ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Heart Valve ◽  
Heart Valves ◽  
Three Dimensional ◽  
Porcine Heart

Biomechanical Simulations of Bioprosthetic Heart Valve Deformations

2006 ◽  
Author(s):  
Wei Sun ◽  
Hengchu Cao ◽  
Jim Davidson ◽  
Michael Sacks
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Stress Concentrations ◽  
Bioprosthetic Heart Valves ◽  
Structural Fatigue ◽  
Structural Deterioration ◽  
Bending Stresses ◽  
Improved Performance ◽  
Valve Prostheses ◽  
Opening And Closing

Previous research has suggested that the structural deterioration in porcine bioprosthetic heart valves (BHV) may be correlated with the regions of high tensile and bending stresses acting on the leaflets during opening and closing[1, 2]. Stress concentrations within the cusp can either directly accelerate tissue structural fatigue damage, or initiate calcification by causing structural disintegration, enabling multiple pathways of calcification that can lead to valve failure[3,4]. In the case of bovine pericardial heart valve prostheses, structural failure of the leaflets is rare but calcification has been observed. Although details of the process are unclear, it is generally assumed that the design of the pericardial valve, which gives a stress-reduced state of the leaflets, is likely to provide improved performance in long-term applications.

Long-term Follow-up (One to Four Years) of Heart Valve Prostheses (102 Consecutive Patients)

1969 ◽  
Vol 56 (5) ◽  
pp. 440-446 ◽  
Author(s):  
Morris J. Levy ◽  
Bernard Vidne ◽  
Jack Salomon ◽  
Daniel Eshkol
Keyword(s):  
Heart Valve ◽  
Heart Valve Prostheses ◽  
Long Term Follow Up ◽  
Valve Prostheses

scholarly journals Prophylaxis of thrombotic complications in a pregnant patients with prosthetic heart valves

2012 ◽  
Vol 61 (5) ◽  
pp. 10-24
Author(s):  
Aleksandr Davidovich Makatsariya ◽  
Viktoriya Omarovna Bitsadze ◽  
Dzhamilya Khizriyevna Khizroyeva ◽  
Vyacheslav Borisovich Nemirovskiy ◽  
Svetlana Vladimirovna Akinshina
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Anticoagulation Therapy ◽  
Mechanical Heart Valve ◽  
Prosthetic Heart Valves ◽  
Dose Selection ◽  
Heart Valve Prostheses ◽  
Adequate Dose ◽  
Thrombotic Complications ◽  
Valve Prostheses

In patients with prosthetic heart valves pregnancy and labor are associated with high risk. There are no established anticoagulation guidelines in pregnant women with mechanical heart valve prostheses. More often physiological hypercoagulable state during pregnancy can reveal acquired and/or inherited hemostasis abnormalities which were asymptotic before pregnancy. The presence in the history of patients the foetal loss syndrome, severe obstetric complications (severe preeclampsia, abruptio placenta, antenatal fetal death, feto-placental insufficiency), thrombosis events is an indication for the screening for genetic thrombophilia and antiphospholipid syndrome. The diagnosis of thrombophilia in patients with mechanical heart valve prostheses can explain the inefficiency of anticoagulation therapy, warfarin resistance, «floating» hemostasis markers and difficulties in adequate dose selection

scholarly journals P1521 Prosthetic heart valve-related stroke: a single center experience

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
A Almaghraby ◽  
M Abdelnabi ◽  
Y Saleh ◽  
O Abdelkarim ◽  
O Ozden Tok ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Stroke ◽  
Heart Valve ◽  
Heart Valves ◽  
Hemorrhagic Stroke ◽  
Mechanical Valve ◽  
Prosthetic Heart Valves ◽  
Single Center ◽  
Single Center Experience ◽  
Valve Prostheses

Abstract OnBehalf YIG-CVR Introduction Thromboembolic events or bleeding are by far the most frequent complications of prosthetic heart valves. Cerebrovascular stroke is one of the major thromboembolic complications of anticoagulation-related issues of prosthetic heart valves. Aim of the work To determine the pattern and risk factors of acute stroke in patients with prosthetic heart valves. Methods and Patients A retrospective single-center analysis of the database registry of consecutive acute stroke patients with mitral or aortic heart valve prostheses admitted to a tertiary care stroke specialized center from 01/01/2012 to 01/12/2017. All patients were examined by a certified neurologist and underwent a complete work-up evaluation (Computed Tomography or Magnetic Resonance Imaging, Carotid Doppler ultrasound examination, complete blood tests, and electrocardiogram) and a transthoracic echocardiography (TTE) examination as well as transesophageal echocardiography (TOE) if valve dysfunction or thrombosis were suspected. Results 214 patients with mitral or aortic valve prostheses were admitted by acute stroke in the duration from 01/01/2012 to 01/12/2017 with a mean age of 44 ± 15 years, 132 were males (61.7%) and 178 patients had mechanical valves (83.2%). 135 patients had mitral prosthesis (63.1%) and ischemic stroke was encountered in 151 patients (70.6%). Conclusion In a single center experience, mechanical prosthesis at the mitral valve position was associated with higher incidence of ischemic stroke. Proper close follow-up of INR levels as well as the surgical shift to biological instead of mechanical valve should decrease significantly the incidence of prosthetic valve related strokes. Baseline, clinical and other parameters Patients (n = 214) Age (years) 44 ± 15 Mechanical valve 178 (83.2%) Atrial Fibrillation 101 (47.2%) Rheumatic Heart Disease 175 (81.8%) Left ventricular ejection fraction (%) 54 ±13 Mitral Only 135 (63.1%) Aortic Only 51 (23.8%) Double Valve Prosthesis 28 (13.1%) Ischemic stroke 151 (70.6%) Hemorrhagic stroke 47 (22%) Both ischemic and hemorrhagic stroke 16 (7.4%) Data are represented as mean(±SD) or number (Percentage) Abstract P1521 Figure. Valve sites

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