scholarly journals Application of Computational Biomechanics in Bioprosthetic Heart Valve Design

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Wei Sun ◽  
Milton DeHerrera
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Anticoagulation Therapy ◽  
Design Parameters ◽  
Effective Orifice Area ◽  
Valve Design ◽  
Prosthetic Devices ◽  
Computational Biomechanics ◽  
Biomechanical Behavior ◽  
Hemodynamic Performance

For more than 40years, the replacement of diseased natural heart valves with prosthetic devices has dramatically improved the quality and length of the lives of millions of patients. Bioprosthetic heart valves (BHV), which are composed of biologically derived tissues, have good hemodynamic performance and do not require the anticoagulation therapy necessary when mechanical heart valves are implanted. However, these bioprostheses continue to fail due to structural failure resulting from poor tissue durability and faulty design. AHA∕ACC guideline recommends use of BHV for patients 65years or older, primarily due to its current 10–15years of limited durability. Clearly, an in-depth understanding of the biomechanical behavior of BHV is essential to improving BHV design to reduce rates of failure and increase its durability. Objective: develop a robust computational model to simulate BHV deformations and optimize its design. Methods: Experimentally driven, nonlinear, anisotropic material models are used for modeling the mechanical properties of valve leaflets; A novel method of constructing parametric finite element models is used to rapidly generate 3D free-from geometries of BHV for valve design optimization; Valve design parameters, such as peak stresses and effective orifice area (EOA) are evaluated. Results: multiple applications of the approach demonstrate the feasibility of utilizing computational biomechanics in BHV design. The computational approach provides us with an efficient new platform to develop and optimize the next generation heart valve design such as transcatheter valve and valve repair device design.

Correlating Leaflet Design and Closing Dynamics With Turbulent Flows Near Bileaflet Mechanical Heart Valves

2008 ◽  
Author(s):  
Luke H. Herbertson ◽  
Steven Deutsch ◽  
Keefe B. Manning
Keyword(s):  
Experimental Study ◽  
Fluid Mechanics ◽  
Turbulent Flows ◽  
Heart Valve ◽  
Environmental Conditions ◽  
Heart Valves ◽  
Anticoagulation Therapy ◽  
Mechanical Heart Valves ◽  
Valve Design ◽  
Made In

Significant advances have been made in the field of heart valve replacement, especially in terms of anticoagulation therapy and valve design. Mechanical heart valves have been successfully implanted for decades to replace irreparable diseased or failing native valves. However, heart valve patients remain more susceptible to hemolysis and thrombosis [1]. In this experimental study, we focus on the closing dynamics of bileaflet mechanical heart valves to better understand the roles that valve design and environmental conditions have on the local fluid mechanics.

Computational Evaluation of the Haemodynamic Performance of a Novel Prosthetic Heart Valve

2017 ◽  
Author(s):  
Mrudang Mathur ◽  
Ankit Saxena ◽  
Rohan Shad ◽  
Anwesha Chattoraj
Keyword(s):  
Heart Valve ◽  
Clinical Performance ◽  
Computational Study ◽  
Anticoagulation Therapy ◽  
Mechanical Heart Valve ◽  
Prosthetic Heart Valve ◽  
Effective Orifice Area ◽  
Computational Evaluation ◽  
Flow Through ◽  
Hemodynamic Performance

It has become evident through studies both computational and otherwise, that the characteristics of blood flow through a mechanical heart valve is closely tied to its thrombogenic profile and clinical performance. Despite progress in the field, there remains an unmet clinical need for a heart valve that is both durable and free from the need for anticoagulation therapy. We designed a prototype for a novel mechanical heart valve with the aim of improving hemodynamic performance and obviating the need for anticoagulant therapy. In this paper we present the results of a computational study that compared our prototype mechanical heart valve with a popular commercially available valve, the Medtronic ATS valve. Our results show that the unique design features of our prototype leads to a reduction turbulent flow, along with a reduction in velocity jets by up to 28%, pressure gradient across the valve by 36.7%, and increases in the effective orifice area of the valve by 25.7%.

scholarly journals Decellularized tissue-engineered heart valves calcification: what do animal and clinical studies tell us?

2020 ◽  
Vol 31 (12) ◽  
Author(s):  
Adel F. Badria ◽  
Petros G. Koutsoukos ◽  
Dimosthenis Mavrilas
Keyword(s):  
Heart Valve ◽  
Clinical Studies ◽  
Heart Valves ◽  
Early Stage ◽  
Anticoagulation Therapy ◽  
Complex Nature ◽  
In Silico Studies ◽  
Decellularized Tissue ◽  
Tissue Engineered Heart Valves

AbstractCardiovascular diseases are the first cause of death worldwide. Among different heart malfunctions, heart valve failure due to calcification is still a challenging problem. While drug-dependent treatment for the early stage calcification could slow down its progression, heart valve replacement is inevitable in the late stages. Currently, heart valve replacements involve mainly two types of substitutes: mechanical and biological heart valves. Despite their significant advantages in restoring the cardiac function, both types of valves suffered from serious drawbacks in the long term. On the one hand, the mechanical one showed non-physiological hemodynamics and the need for the chronic anticoagulation therapy. On the other hand, the biological one showed stenosis and/or regurgitation due to calcification. Nowadays, new promising heart valve substitutes have emerged, known as decellularized tissue-engineered heart valves (dTEHV). Decellularized tissues of different types have been widely tested in bioprosthetic and tissue-engineered valves because of their superior biomechanics, biocompatibility, and biomimetic material composition. Such advantages allow successful cell attachment, growth and function leading finally to a living regenerative valvular tissue in vivo. Yet, there are no comprehensive studies that are covering the performance of dTEHV scaffolds in terms of their efficiency for the calcification problem. In this review article, we sought to answer the question of whether decellularized heart valves calcify or not. Also, which factors make them calcify and which ones lower and/or prevent their calcification. In addition, the review discussed the possible mechanisms for dTEHV calcification in comparison to the calcification in the native and bioprosthetic heart valves. For this purpose, we did a retrospective study for all the published work of decellularized heart valves. Only animal and clinical studies were included in this review. Those animal and clinical studies were further subcategorized into 4 categories for each depending on the effect of decellularization on calcification. Due to the complex nature of calcification in heart valves, other in vitro and in silico studies were not included. Finally, we compared the different results and summed up all the solid findings of whether decellularized heart valves calcify or not. Based on our review, the selection of the proper heart valve tissue sources (no immunological provoking residues), decellularization technique (no damaged exposed residues of the decellularized tissues, no remnants of dead cells, no remnants of decellularizing agents) and implantation techniques (avoiding suturing during the surgical implantation) could provide a perfect anticalcification potential even without in vitro cell seeding or additional scaffold treatment.

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

Research Contribution of Prosthetic Valve Manufacturers Interfacing Academic-Industry Research Efforts

1999 ◽  
Author(s):  
Xiao Gong ◽  
Yi-Ren Woo ◽  
Ajit P. Yoganathan ◽  
Andreas Anayiotos
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Clinical Performance ◽  
Thrombus Formation ◽  
Academic Research ◽  
Prosthetic Heart Valve ◽  
Structural Safety ◽  
Prosthetic Heart Valves ◽  
Implantable Medical Device ◽  
Valve Design

Abstract Prosthetic heart valve is one of the most successful implantable medical devices. However, introducing better performing and longer lasting prosthetic mechanical heart valves (MHV) into clinical use has been slow because predicting the long term performance of a new valve design is difficult. Although significant progresses in many scientific fronts relevant to prosthetic heart valve development have been achieved, we still have an imperfect understanding of host responses to an implantable medical device and incomplete knowledge in associating hemodynamic characteristics of a valve design to clinical performance. Valve designers, frequently need to over design the valve components to ensure structural safety and thus, sacrifice the opportunity to optimize performance. Complications such as infection, thrombus formation, thromboembolic incidents, and hemorrhage associated to the use of prosthetic valves are still reported and valve designers are working hard to eliminate them. Further advancing scientific knowledge in designing and evaluating prosthetic heart valves is of great interest to many Valve designers and manufacturers. Interfacing Industry and Academic research efforts has been thwarted due to predominantly proprietary issues. Considering the benefits of a better performing MHV to the patients, this industry session will bring researchers from various MHV companies and academic institutions to discuss how to share the results of scientific studies more effectively. This will help accelerate new MHV development without compromising the confidentiality of key valve design information. The issue of standardized MHV testing will also be addressed.

Simulated Bioprosthetic Heart Valve Deformation under Quasi-Static Loading

2005 ◽  
Vol 127 (6) ◽  
pp. 905-914 ◽  
Author(s):  
Wei Sun ◽  
Ajay Abad ◽  
Michael S. Sacks
Keyword(s):  
Heart Valves ◽  
Constitutive Models ◽  
Material Model ◽  
Structural Failure ◽  
Bioprosthetic Heart Valves ◽  
Prosthetic Devices ◽  
Biomechanical Behavior ◽  
Biaxial Tests ◽  
Parametric Studies ◽  
Good Agreement

For more than 40years, the replacement of diseased natural heart valves with prosthetic devices has dramatically extended the quality and length of the lives of millions of patients worldwide. However, bioprosthetic heart valves (BHV) continue to fail due to structural failure resulting from poor tissue durability and faulty design. Clearly, an in-depth understanding of the biomechanical behavior of BHV at both the tissue and functional prosthesis levels is essential to improving BHV design and to reduce rates of failure. In this study, we simulated quasi-static BHV leaflet deformation under 40, 80, and 120mmHg quasi-static transvalvular pressures. A Fung-elastic material model was used that incorporated material parameters and axes derived from actual leaflet biaxial tests and measured leaflet collagen fiber structure. Rigorous experimental validation of predicted leaflet strain field was used to validate the model results. An overall maximum discrepancy of 2.36% strain between the finite element (FE) results and experiment measurements was obtained, indicating good agreement between computed and measured major principal strains. Parametric studies utilizing the material parameter set from one leaflet for all three leaflets resulted in substantial variations in leaflet stress and strain distributions. This result suggests that utilization of actual leaflet material properties is essential for accurate BHV FE simulations. The present study also underscores the need for rigorous experimentation and accurate constitutive models in simulating BHV function and design.

Abstract 17101: Low-intensity Anticoagulant Treatment in Chinese Patients with Mechanical Heart Valve Prostheses: Early Outcomes of a Prospective, Multicenter Registry in China

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
JIA HU ◽  
BO FU ◽  
Jian-ping Xu ◽  
Ying-kang Shi ◽  
Li Dong
Keyword(s):  
Valve Replacement ◽  
Heart Valve ◽  
Heart Valves ◽  
Anticoagulation Therapy ◽  
Mechanical Heart Valve ◽  
Heart Valve Replacement ◽  
Chinese Patients ◽  
Anticoagulant Treatment ◽  
Low Intensity

Background: Current guidelines recommend vitamin K antagonist treatment with relatively higher international normalized ratio (INR) targets for patients with mechanical heart valve prostheses. However, there is lack of data from large clinical trials about the outcomes of low-intensity anticoagulant treatment in Chinese patients with mechanical heart valves. Methods: The Low-intensity Anticoagulation Therapy after Heart Valve Replacement is an ongoing multicenter, prospective, observational cohort study (ChiCTR-OCH-10001185). Between January 2011 and August 2013, qualified patients from 34 cardiac centers in China mainland were recruited in the Anticoagulation Therapy Database of Chinese Patients after Heart Valve Replacement. Baseline characteristics were collected and patients were followed up for anticoagulant treatment, INRs and adverse events till March 2014. Results: The database recruited 11,769 patients, and 11,040 patients (93.8%) undergoing mechanical heart valve replacement were analyzed in this study. The mean age was 48.9±11.5 years and 6,227 patients (56.4%) were female. A total of 9,870 patients (89.4%) of the baseline population completed at least 6 months follow-up. The median follow-up time was 1.2 years (range 0.5-2.2). For all 9,870 patients, 143,115 measurements of the INR were obtained. The average warfarin dosage was 2.98±1.16mg/d and the mean INR was 1.81±0.46, and 88.7% patients had an INR level≤2.5 during the follow-up period. The incidence of hemorrhagic events was the lowest in patients with an INR≤2.0, whereas the risk of thromboembolic complications in this group of patients was not significantly increased (Table 1). Conclusions: Low-intensity anticoagulation with an INR of 1.5 to 2.5 is safe and effective for Chinese patients with mechanical heart valves in short-term. The optimal INR targets for mechanical valve recipients with different implanting positions and risk factors require further investigation.

Simulations of the Hinge Flow Fields of a Bileaflet Mechanical Heart Valve Under Physiologic Pulsatile Aortic Conditions

2008 ◽  
Author(s):  
Hélène A. Simon ◽  
Liang Ge ◽  
Iman Borazjani ◽  
Fotis Sotiropoulos ◽  
Ajit P. Yoganathan
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Mechanical Heart Valve ◽  
Prosthetic Heart Valve ◽  
Prosthetic Heart Valves ◽  
Valve Design ◽  
Bileaflet Mechanical Heart Valve ◽  
Hinge Flow ◽  
Blood Elements

Native heart valves with limited functionality are commonly replaced by prosthetic heart valves. Since the first heart valve replacement in 1960, more than three million valves have been implanted worldwide. The most widely implanted prosthetic heart valve design is currently the bileaflet mechanical heart valve (BMHV), with more than 130,000 implants every year worldwide. However, studies have shown that this valve design can still cause major complications, including hemolysis, platelet activation, and thromboembolic events. Clinical reports and recent in vitro experiments suggest that these thrombogenic complications are associated with the hemodynamic stresses imposed on blood elements by the complex non-physiologic flow induced by the valve, in particular in the hinge region.

Recent Advances in Polymeric Heart Valves Research

2011 ◽  
Vol 1 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Yee Han Kuan ◽  
Lakshmi Prasad Dasi ◽  
Ajit Yoganathan ◽  
Hwa Liang Leo
Keyword(s):  
Valve Replacement ◽  
Heart Valve ◽  
Animal Studies ◽  
Heart Valves ◽  
Heart Valve Replacement ◽  
Artificial Heart Valve ◽  
Polymer Science ◽  
Cardiovascular Devices ◽  
Valve Prostheses ◽  
Hemodynamic Performance

Heart valve replacement is fast becoming a routine surgery worldwide, and heart valve prostheses are today considered among the most widely used cardiovascular devices. Mechanical and bioprostheses have been the traditional choices to the replacement surgeries. However, such valves continue to expose patients to risks including thrombosis, infection and limited valve durability. In recent years, advances in polymer science give rise to an important new class of artificial heart valve made predominantly of polyurethane-based materials, which show improved biocompatibility and biostability. These polymeric heart valves have demonstrated excellent hemodynamic performance and good durability with excellent fatigue stress resistance. Advancements in the designs and manufacturing methods also suggested improved in the durability of polymeric heart valves. Animal studies with these valves have also shown good biocompatibility with minimal calcification of the valve leaflets. With these promising progresses, polymeric heart valves could be a viable alternative in the heart valve replacement surgeries in the near future.

scholarly journals Indications for echocardiography of replacement heart valves: a joint statement from the British Heart Valve Society and British Society of Echocardiography

2019 ◽  
Vol 6 (1) ◽  
pp. G9-G15 ◽  
Author(s):  
John B Chambers ◽  
Madalina Garbi ◽  
Norman Briffa ◽  
Vishal Sharma ◽  
Richard P Steeds
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Vital Role ◽  
British Society ◽  
Systemic Hypertension ◽  
Valve Design ◽  
Related Factors ◽  
Structural Valve Deterioration ◽  
Patient Prosthesis Mismatch

Echocardiography plays a vital role in the follow-up of patients with replacement heart valves. However, there is considerable variation in international guidelines regarding the recommended time points after implantation at which routine echocardiography should be performed. The purpose of routine echocardiography is to detect early structural valve deterioration in biological valves to improve the timing of redo interventions. However, the risk of valve deterioration depends on many valve-related factors (valve design and patient prosthesis mismatch) and patient-related factors (age, diabetes, systemic hypertension, renal dysfunction and smoking). In this statement, the British Heart Valve Society and the British Society of Echocardiography suggest practical guidance. A plan should be made soon after implantation, but this may need to be modified for individual patients and as circumstances change. It is important that patients are managed in a multidisciplinary valve clinic.

Sign in / Sign up

Export Citation Format

Share Document