Development and Optimization of a Novel Polymeric Prosthetic Heart Valve Using the Device Thrombogenicity Emulation (DTE) Methodology

Author(s):  
Thomas E. Claiborne ◽  
Michalis Xenos ◽  
Jawaad Sheriff ◽  
Dinesh Peter ◽  
Yared Alemu ◽  
...  

Calcific aortic valve disease (CAVD) is the most common and life threatening form of valvular heart disease, characterized by stenosis and regurgitation, which is currently treated at the symptomatic end-stages via open-heart surgical replacement of the diseased valve with typically either a xenograft tissue valve or mechanical heart valve. These options offer the clinician a choice between structural valve deterioration and anticoagulant therapy respectively, effectively replacing one disease with another [1]. Polymeric heart valves (PHV) offer the promise of reducing or eliminating these complications [2] and may be efficacious for patients who cannot tolerate cardiothoracic surgery by using instead transcatheter valve implantation (TAVI) [3], where there is evidence that tissue valves are damaged during implantation [4], and in pulsatile circulatory support devices such as the SynCardia Total Artificial Heart. But development of PHVs has been slow due to the lack of sufficiently durable and biocompatible formulations.

2020 ◽  
Vol 7 (3) ◽  
pp. 90
Author(s):  
Othman Smadi ◽  
Anas Abdelkarim ◽  
Samer Awad ◽  
Thakir D. Almomani

The prosthetic heart valve is vulnerable to dysfunction after surgery, thus a frequent assessment is required. Doppler electrocardiography and its quantitative parameters are commonly used to assess the performance of the prosthetic heart valves and provide detailed information on the interaction between the heart chambers and related prosthetic valves, allowing early detection of complications. However, in the case of the presence of subaortic stenosis, the accuracy of Doppler has not been fully investigated in previous studies and guidelines. Therefore, it is important to evaluate the accuracy of the parameters in such cases to get early detection, and a proper treatment plan for the patient, at the right time. In the current study, a CFD simulation was performed for the blood flow through a Bileaflet Mechanical Heart Valve (BMHV) with concomitant obstruction in the Left Ventricle Outflow Tract (LVOT). The current study explores the impact of the presence of the subaortic on flow patterns. It also investigates the accuracy of (BMHV) evaluation using Doppler parameters, as proposed in the American Society of Echocardiography (ASE) guidelines.


Author(s):  
Ankit Saxena ◽  
Rohan Shad ◽  
Mrudang Mathur ◽  
Anwesha Chattoraj ◽  
Sujay Shad

We developed a new mechanical heart valve prototype with a unique mechanism for attachment to cardiac tissue. The development of novel prosthetic heart valve systems requires careful assessment of paravalvular leaks — leakage of fluid that takes place between the valve and the cardiac tissue it is attached to. Traditional methods of testing paravalvular leaks in flow chambers are not ideal for novel devices and may underestimate its true extent. In this paper we developed a novel method of quantifying paravalvular leaks involving the use of 3D printed prototype heart valves and cadaveric bovine hearts, and compared the results with those from commercially available Medtronic ATS mechanical bileaflet valves. The average leak in our final prototype heart valves were found to be 0.13 ml/sec, compared to 0.33 ml/sec in the ATS valve.


Author(s):  
Thomas E. Claiborne ◽  
Wei-Che Chiu ◽  
Marvin J. Slepian ◽  
Danny Bluestein

Thrombotic complications, such as hemorrhage or embolism, remain a major concern of blood contacting medical devices [1], including prosthetic heart valves (PHV) and mechanical circulatory support devices, e.g. ventricular assist devices (VAD) or the Total Artificial Heart (TAH) [2]. In most cases device recipients require life-long anticoagulation therapy, which increases the risk of hemorrhagic stroke and other bleeding disorders. In order to obviate the need for anticoagulants and reduce stroke risks, our group developed a unique optimization methodology, Device Thrombogenicity Emulation (DTE) [2–5]. With the DTE, the thrombogenic potential of a device is evaluated using extensive numerical modeling and calculating multiple platelet trajectories flowing through the device. The platelet stress-time waveforms are then emulated in our Hemodynamic Shearing Device (HSD) and their activation level is measured with our Platelet Activation State (PAS) assay. This provides a proxy validation of the simulation. We identify high shear stress producing regions within the device and modify its design to reduce or eliminate those potentially thrombogenic ‘hot-spots.’ Through an iterative process, we can optimize the device design prior to prototyping.


Author(s):  
Hélène A. Simon ◽  
Liang Ge ◽  
Iman Borazjani ◽  
Fotis Sotiropoulos ◽  
Ajit P. Yoganathan

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.


2018 ◽  
Vol 68 (02) ◽  
pp. 099-106 ◽  
Author(s):  
Charles Mve Mvondo ◽  
Marta Pugliese ◽  
Jean Claude Ambassa ◽  
Alessandro Giamberti ◽  
Emanuele Bovio ◽  
...  

Abstract Background The management of patients with mechanical heart valves remains a major concern in populations with limited resources and medical facilities. This study reports the clinical outcomes of patients who underwent mechanical valve implantation in a sub-Saharan center over an 8-year period. Methods A total of 291 mechanical valves were implanted in 233 patients in our institution between February 2008 and June 2016. A total of 117 patients underwent mitral valve replacement (MVR, 50.2%), 57 had aortic valve replacement (AVR, 24.4%), and 59 underwent both AVR and MVR (double valve replacement [DVR], 25.7%). The mean age at surgery was 27.6 ± 13.4 years (range, 7–62 years). Rheumatic etiology was found in 80.6% of the patients. Hospital mortality, late deaths, and valve-related events were reviewed at follow-up (839 patient-years, range: 1–9.4 years, complete in 93%). Results The 30-day mortality was 4.7% (11/233). The overall survival at 1 and 6 years for the whole cohort was 88.8 ± 2.1% and 78.7 ± 3.3%, respectively. The 6-year survival for AVR, MVR, and DVR was 89.3 ± 4.8%, 73.2 ± 5.4%, and 79.3 ± 5.8%, respectively (p = 0.15). The freedom from neurologic events and anticoagulation-related bleeding at 6 years was 93.1 ± 2.1% and 78.9 ± 3.7%, respectively. No patient had reoperation at follow-up. No case of prosthetic valve thrombosis was identified. Eight full-term pregnancies were reported. Conclusion This preliminary experience reports acceptable midterm results after mechanical heart valve implantation in our region. Both accurate surgical evaluation and strategies, either financial or social, facilitating patient's education and medical assistance are crucial to ensure good results. Long-term follow-up and further studies comparing current nonthrombogenic options are warranted to draw reliable conclusions.


Author(s):  
B. Min Yun ◽  
Lakshmi P. Dasi ◽  
Cyrus K. Aidun ◽  
Ajit P. Yoganathan

Prosthetic heart valves have been used for over 50 years to replace diseased native valves but still lead to severe complications such as platelet aggregation and thromboembolic events. The most widely implanted design is the bileaflet mechanical heart valve (BMHV). Most modern BMHV designs have better flow hemodynamics and blood damage performance than earlier-generation counterparts. However, blood element trauma and thromboembolic events still remain as major complications of current BMHV designs. These problems have been linked to blood damage caused by non-physiological stresses. These stresses are caused by the complex flow fields that arise due to prosthetic heart valve design. In order to reduce the severity of these complications, the blood damage that occurs in flows through prosthetic heart valves must be well understood.


Author(s):  
Othman Smadi ◽  
Zahra Keshavarz-Motamed ◽  
Ibrahim Hassan ◽  
Philippe Pibarot ◽  
Lyes Kadem

Left heart side (left ventricle and left atrium) is responsible for delivering the oxygenated blood to all body organs, where a relatively strong left ventricle contraction is needed to deliver around 5 liters of blood per minute. As a consequence, the left heart side experiences a high pressure (∼150 mmHg). Therefore, the dysfunction (stenosis or incompetence) in the aortic and/or mitral heart valves in the left side of the heart is more common than the dysfunction in the pulmonary and tricuspid heart valves in the right side of the heart (Yoganathan et al., 2004). Heart valve surgical replacement is the most effective solution in severe functional heart valve disease (Pibarot and Dumesnil, 2009). Almost, half of the total implants of prosthetic heart valves (∼300,000) are mechanical (mainly bileaflet). In case of mechanical heart valve (MHV), a lifelong anti-coagulant should be taken to avoid thromboembolic events. Despite the significant improvement in valve design resulting in minimizing prosthetic valve complications (thromboembolic events or pannus formation), these complications are still possible with MHV Implantation.


Author(s):  
B. Min Yun ◽  
Jingshu Wu ◽  
Cyrus K. Aidun ◽  
Ajit P. Yoganathan

Prosthetic heart valves have been used for over 50 years to replace diseased native valves but still lead to severe complications such as hemolysis, platelet aggregation, and thromboembolic events. The most widely implanted design is the bileaflet mechanical heart valve (BMHV). Most modern BMHV designs have better flow hemodynamics and blood damage performance than their earlier-generation counterparts. However, blood element trauma and thromboembolic events still remain as major complications of current BMHV designs. These problems have been linked to blood element damage caused by non-physiological stresses. These stresses are caused by the complex flow fields that arise due to prosthetic heart valve design, particularly in the leaflet hinge region. In order to reduce the severity of these complications, the blood damage that occurs in flows through prosthetic heart valves must be well understood.


2020 ◽  
Vol 3 (10) ◽  
pp. 01-05
Author(s):  
Marco Angelillis

Transcatheter valve in valve (ViV) implantation actually represents a valid alternative to surgical reinterventions in patients with previous surgical aortic valve replacement (AVR). In patients less than 80 years old, it is crucial to correctly position the new valve leaving a feasible and easy access to coronary ostia, both for future percutaneous coronary intervention (PCI) than for a future possible TAVinTAV procedure. We report a 71 year old man with prior AVR presented with structural valve deterioration (SVD) leading to severe aortic stenosis. In order to guarantee comfortable coronary access we aligned, the commissures of the new percutaneous valve with the ones of the surgical bioprothesis by reconstructing the headframes of the surgical bioprosthesis with computer tomography (CT) and fluoro-CT.


2021 ◽  
Author(s):  
Mengyue Hu ◽  
Xu Peng ◽  
Yang Zhao ◽  
Xiaoshuang Yu ◽  
Can Cheng ◽  
...  

To conveniently and effectively cure heart valve diseases or defects, combining with transcatheter valve technology, bioprosthetic heart valves (BHVs) originated from the decellularized porcine pericardium (D-PP) have been broadly used...


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