A Method for Real-Time In Vitro Observation of Cavitation on Prosthetic Heart Valves

1994 ◽  
Vol 116 (4) ◽  
pp. 460-468 ◽  
Author(s):  
Conrad M. Zapanta ◽  
Edward G. Liszka ◽  
Theodore C. Lamson ◽  
David R. Stinebring ◽  
Steve Deutsch ◽  
...  
Keyword(s):  
Real Time ◽  
Heart Valve ◽  
Cavity Growth ◽  
Prosthetic Heart Valve ◽  
Aortic Pressure ◽  
Atrial Pressure ◽  
Prosthetic Heart Valves ◽  
Distilled Water ◽  
Beat Rate

A method for real-time in vitro observation of cavitation on a prosthetic heart valve has been developed. Cavitation of four blood analog fluids (distilled water, aqueous glycerin, aqueous polyacrylamide, and aqueous xanthan gum) has been documented for a Medtronic/Hall™ prosthetic heart valve. This method employed a Penn State Electrical Ventricular Assist Device in a mock circulatory loop that was operated in a partial filling mode associated with reduced atrial filling pressure. The observations were made on a valve that was located in the mitral position, with the cavitation occurring on the inlet side after valve closure on every cycle. Stroboscopic videography was used to document the cavity life cycle. Bubble cavitation was observed on the valve occluder face. Vortex cavitation was observed at two locations in the vicinity of the valve occluder and housing. For each fluid, cavity growth and collapse occurred in less than one millisecond, which provides strong evidence that the cavitation is vaporous rather than gaseous. The cavity duration time was found to decrease with increasing atrial pressure at constant aortic pressure and beat rate. The area of cavitation was found to decrease with increasing delay time at a constant aortic pressure, atrial pressure, and beat rate. Cavitation was found to occur in each of the fluids, with the most cavitation seen in the Newtonian fluids (distilled water and aqueous glycerin).

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.

The Design, Fabrication and Evaluation of a Trileaflet Prosthetic Heart Valve

1980 ◽  
Vol 102 (1) ◽  
pp. 34-41 ◽  
Author(s):  
G. E. Chetta ◽  
J. R. Lloyd
Keyword(s):  
Heart Valve ◽  
Performance Index ◽  
Test Section ◽  
Heart Valves ◽  
Prosthetic Heart Valve ◽  
Prosthetic Heart Valves ◽  
In Vitro Evaluation ◽  
Design Considerations ◽  
Evaluation Techniques

Although prosthetic heart valves have been in existence for many years, the need for new improved designs and in-vitro evaluation techniques are apparent. This paper presents details on the design considerations, fabrication techniques and heart valve evaluation equipment. A valve performance index is discussed in light of various valve and mock circulatory test section designs. The need for national and indeed international valve evaluation techniques is made apparent.

The Influence of the Aortic Root Geometry on Flow Characteristics of a Prosthetic Heart Valve

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Oleksandr Barannyk ◽  
Peter Oshkai
Keyword(s):  
Aortic Valve ◽  
Heart Valve ◽  
Aortic Root ◽  
Reynolds Shear Stress ◽  
Prosthetic Heart Valve ◽  
Flow Characteristics ◽  
Aortic Pressure ◽  
Valve Prosthesis ◽  
Aortic Heart Valve ◽  
Valve Diseases

In this paper, performance of aortic heart valve prosthesis in different geometries of the aortic root is investigated experimentally. The objective of this investigation is to establish a set of parameters, which are associated with abnormal flow patterns due to the flow through a prosthetic heart valve implanted in the patients that had certain types of valve diseases prior to the valve replacement. Specific valve diseases were classified into two clinical categories and were correlated with the corresponding changes in aortic root geometry while keeping the aortic base diameter fixed. These categories correspond to aortic valve stenosis and aortic valve insufficiency. The control case that corresponds to the aortic root of a patient without valve disease was used as a reference. Experiments were performed at test conditions corresponding to 70 beats/min, 5.5 L/min target cardiac output, and a mean aortic pressure of 100 mmHg. By varying the aortic root geometry, while keeping the diameter of the orifice constant, it was possible to investigate corresponding changes in the levels of Reynolds shear stress and establish the possibility of platelet activation and, as a result of that, the formation of blood clots.

scholarly journals Hemodynamic Performance of Dysfunctional Prosthetic Heart Valve with the Concomitant Presence of Subaortic Stenosis: In Silico Study

2020 ◽  
Vol 7 (3) ◽  
pp. 90
Author(s):  
Othman Smadi ◽  
Anas Abdelkarim ◽  
Samer Awad ◽  
Thakir D. Almomani
Keyword(s):  
Early Detection ◽  
Heart Valve ◽  
Heart Valves ◽  
Cfd Simulation ◽  
Treatment Plan ◽  
Mechanical Heart Valve ◽  
Prosthetic Heart Valve ◽  
Subaortic Stenosis ◽  
Prosthetic Heart Valves ◽  
The Impact

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.

Turbulent Flows Through a Disk-Type Prosthetic Heart Valve

1983 ◽  
Vol 105 (3) ◽  
pp. 263-267 ◽  
Author(s):  
W. J. Yang ◽  
J. H. Wang
Keyword(s):  
Turbulent Flows ◽  
Heart Valve ◽  
Stokes Equations ◽  
Turbulent Viscosity ◽  
Prosthetic Heart Valve ◽  
Equation Model ◽  
Velocity Shear ◽  
Navier Stokes ◽  
Normal Stresses

A numerical model is developed to predict the complex velocity, shear and pressure fields in steady turbulent flow through a disk-type prosthetic heart valve in a constant diameter chamber. The governing Navier-Stokes equations are reduced to a set of simultaneous algebraic finite-difference equations which are solved by a fast-converging line-iterations technique. A two-parameter, two-equation model is employed to determine the turbulent viscosity. Numerical results are obtained for stream function, vorticity, and shear and normal stresses. The regions of very high shear and normal stresses in the fluid and at the walls are identified. The maximum value of the shear stress occurring near the upstream corner of the disk may cause hemolysis. The technique can be used together with in-vitro physcial experiments to evaluate existing or future prosthetic heart valve designs.

Modeling Technique of Prosthetic Heart Valves

1984 ◽  
Vol 106 (1) ◽  
pp. 83-88 ◽  
Author(s):  
T. Kitamura ◽  
T. Kijima ◽  
H. Akashi
Keyword(s):  
Real Time ◽  
Heart Valves ◽  
Time Estimation ◽  
Modeling Technique ◽  
Computational Time ◽  
Prosthetic Heart Valves ◽  
The Real ◽  
Hemodynamic State ◽  
Real Time Estimation

This paper demonstrates a modeling technique of prosthetic heart valves. In the modeling, a pumping cycle is divided into four phases, in which the state of the valve and flow is different. The pressure-flow relation across the valve is formulated separately in each phase. This technique is developed to build a mathematical model used in the real time estimation of the hemodynamic state under artificial heart pumping. The model built by this technique is simple enough for saving the computational time in the real time estimation. The model is described by the first-order ordinary differential equation with 12 parameters. These parameters can be uniquely determined beforehand from in-vitro experimental data. It is shown that the model can adapt, with sufficient accuracy, to a change in the practical pumping condition and the viscosity of the fluid in their practical range, and is also demonstrated that the estimated backflow volume by model agrees closely with the actual one.

Modeling of Tissue Fatigue Damage in Bio-Prosthetic Heart Valve

2011 ◽  
Author(s):  
Caitlin Martin ◽  
Wei Sun
Keyword(s):  
Fatigue Damage ◽  
Heart Valve ◽  
Anticoagulant Therapy ◽  
Heart Valves ◽  
Prosthetic Heart Valve ◽  
Bovine Pericardium ◽  
Prosthetic Heart Valves ◽  
Mechanical Valves ◽  
In Vivo Degradation

Bio-prosthetic heart valves (BHVs) with leaflets made of glutaraldehyde-treated bovine pericardium (GLBP), have been used extensively to replace diseased heart valves. BHVs display superior hemodynamics to mechanical valves and eliminate the need for anticoagulant therapy; however, they exhibit poor durability resulting from in vivo degradation and fatigue damage of the leaflets.

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.

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