The Inertia of the Anterior Leaflet of the Heart’s Mitral Valve

2010 ◽  
Author(s):  
Abdullah A. Kendoush ◽  
Muralidhar Padala ◽  
David Icenogle ◽  
Ajit P. Yoganathan
Keyword(s):  
Mitral Valve ◽  
Computational Models ◽  
Virtual Mass ◽  
Complete Model ◽  
Fluid Medium ◽  
Mitral Valves ◽  
Mass Effects ◽  
Mechanical Valves ◽  
Mass Coefficient ◽  
Bileaflet Mechanical Valves

Virtual mass effects generate forces that act on any object accelerating in a fluid medium. While there have been computational models of bileaflet mechanical valves that include virtual mass effects [1], current computational models of fluid structure interaction of native mitral valves do not consider virtual mass effects, resulting in an incomplete measure of the forces acting on the valve. As far as the authors aware no closed-form relationship for the virtual mass coefficient, Cm, of the native mitral valve has been determined. Integrating the effects of virtual mass into computational models of the mitral valve would result in a more complete model, and could yield more accurate and relevant results from computational models of the mitral valve.

Stereoscopic Particle Image Velocimetry of Native Ovine Mitral Valves in a Pulsatile Left Heart Simulator

2012 ◽  
Author(s):  
Jean-Pierre Rabbah ◽  
Neelakantan Saikrishnan ◽  
Ajit P. Yoganathan
Keyword(s):  
Particle Image Velocimetry ◽  
Mitral Valve ◽  
Computational Models ◽  
Particle Image ◽  
Numerical Models ◽  
Stereoscopic Particle Image Velocimetry ◽  
Patient Specific ◽  
Flow Loop ◽  
Mitral Valves ◽  
Image Velocimetry

Patient specific mitral valve computational models are being actively developed to facilitate surgical planning. These numerical models increasingly employ more realistic geometries, kinematics, and mechanical properties, which in turn requires rigorous experimental validation [1]. However, to date, native mitral flow dynamics have not been accurately and comprehensively characterized. In this study, we used Stereoscopic Particle Image Velocimetry (SPIV) to characterize the ventricular flow field proximal to a native mitral valve in a pulsatile experimental flow loop.

scholarly journals Differential cell-matrix responses in hypoxia-stimulated aortic versus mitral valves

2016 ◽  
Vol 13 (125) ◽  
pp. 20160449 ◽  
Author(s):  
Matthew C. Sapp ◽  
Varun K. Krishnamurthy ◽  
Daniel S. Puperi ◽  
Saheba Bhatnagar ◽  
Gabrielle Fatora ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Oxygen Diffusion ◽  
Computational Models ◽  
Valve Disease ◽  
Low Oxygen ◽  
Mitral Valve Leaflet ◽  
Altered Expression ◽  
Mitral Valves ◽  
The Impact ◽  
Diffusion Profiles

Tissue oxygenation often plays a significant role in disease and is an essential design consideration for tissue engineering. Here, oxygen diffusion profiles of porcine aortic and mitral valve leaflets were determined using an oxygen diffusion chamber in conjunction with computational models. Results from these studies revealed the differences between aortic and mitral valve leaflet diffusion profiles and suggested that diffusion alone was insufficient for normal oxygen delivery in mitral valves. During fibrotic valve disease, leaflet thickening due to abnormal extracellular matrix is likely to reduce regional oxygen availability. To assess the impact of low oxygen levels on valve behaviour, whole leaflet organ cultures were created to induce leaflet hypoxia. These studies revealed a loss of layer stratification and elevated levels of hypoxia inducible factor 1-alpha in both aortic and mitral valve hypoxic groups. Mitral valves also exhibited altered expression of angiogenic factors in response to low oxygen environments when compared with normoxic groups. Hypoxia affected aortic and mitral valves differently, and mitral valves appeared to show a stenotic, rheumatic phenotype accompanied by significant cell death. These results indicate that hypoxia could be a factor in mid to late valve disease progression, especially with the reduction in chondromodulin-1 expression shown by hypoxic mitral valves.

Replication of left ventricular haemodynamics with a simple planar mitral valve model

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Anna Daub ◽  
Jochen Kriegseis ◽  
Bettina Frohnapfel
Keyword(s):  
Mitral Valve ◽  
Computational Models ◽  
Vortex Formation ◽  
Flow Characteristics ◽  
Left Ventricular ◽  
Computational Effort ◽  
Type Model ◽  
Diastolic Phase ◽  
Valve Model ◽  
Modelling Approach

AbstractTools for the numerical prediction of haemodynamics in multi-disciplinary integrated heart simulations have to be based on computational models that can be solved with low computational effort and still provide physiological flow characteristics. In this context the mitral valve model is important since it strongly influences the flow kinematics, especially during the diastolic phase. In contrast to a 3D valve, a vastly simplified valve model in form of a simple diode is known to be unable to reproduce the characteristic vortex formation and unable to promote a proper ventricular washout. In the present study, an adaptation of the widely used simplest modelling approach for the mitral valve is employed and compared to a physiologically inspired 3D valve within the same ventricular geometry. The adapted approach shows enhanced vortex formation and an improved ventricular washout in comparison to the diode type model. It further shows a high potential in reproducing the main flow characteristics and related particle residence times generated by a 3D valve.

Are all bileaflet mechanical valves equal?

2009 ◽  
Vol 24 (2) ◽  
pp. 136-141 ◽  
Author(s):  
Michael E Halkos ◽  
John D Puskas
Keyword(s):  
Mechanical Valves ◽  
Bileaflet Mechanical Valves

Functional Evaluation of the Medtronic Stentless Porcine Xenograft Mitral Valve in Sheep

Circulation ◽  
1999 ◽  
Vol 100 (suppl_2) ◽  
Author(s):  
Paul Dagum ◽  
G. Randall Green ◽  
Tomasz A. Timek ◽  
George T. Daughters ◽  
Linda E. Foppiano ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Lateral Displacement ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Control Group ◽  
Attractive Alternative ◽  
Functional Evaluation ◽  
Mitral Valves ◽  
Hemodynamic Performance ◽  
Porcine Xenograft

Background —Recently, renewed interest in allograft and stentless “freehand” bileaflet xenograft mitral valve replacement has arisen. The variability of human papillary tip anatomy and scarcity of donors limit allograft availability, making xenograft mitral valves an attractive alternative; however, these valves require new surgical implantation techniques, and assessment of their hemodynamics and functional geometry is lacking. Methods —Seven sheep underwent implantation of a new stentless, glutaraldehyde-preserved porcine mitral valve (Physiological Mitral Valve [PMV], Medtronic) and were studied acutely under open-chest conditions. A new method of retrograde cardioplegia was developed. Hemodynamic valve function was assessed by epicardial Doppler echocardiography. 3D motion of miniature radiopaque markers sutured to the valve leaflets, annulus, and papillary tips was measured. Six other sheep with implanted markers served as controls. Results —Both papillary muscle tips avulsed in the first animal, leaving 6 other animals. Mitral regurgitation was not observed in any xenograft valve. The peak and mean transvalvular gradients were 4.6±1.8 mm Hg and 2.6±1.5 mm Hg, respectively. The average mitral valve area was 5.7±1.6 cm 2 . Valve closure in the xenograft group occurred later (30±11 ms, P <0.015) and at higher left-ventricular pressure (61±9 mm Hg, P <0.001) than in the control group; furthermore, leaflet coaptation was displaced more apically (5.6±2.2 mm, P <0.001) and septally (5.8±1.5 mm, P <0.001), and the anterolateral papillary tip underwent greater septal-lateral displacement (2.7±1.5 mm, P <0.001). Annular contraction during the cardiac cycle was similar in the 2 groups (xenograft 9.2±4.5% versus control 10.6±4.5% [mean±SD; 2-factor ANOVA model]). Conclusions —Successful freehand stentless porcine mitral valve implantation is feasible in sheep and was associated with excellent early postoperative hemodynamics. Physiological mitral valve annular contraction and functional leaflet closure mechanics were preserved. Long-term valve durability, calcification, and hemodynamic performance remain to be determined in models.

Abstract 14888: Extracellular Matrix Quantification of Fully Regenerated Neochorade After Bio-scaffold Mitral Valve Implantation in a Juvenile Non-human Primate Model

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Brittany A Gonzalez ◽  
Marcos Gonzalez Perez ◽  
Asad Mirza ◽  
Frank Scholl ◽  
Steven Bibevski ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Mitral Valve ◽  
Oscillatory Flow ◽  
Treatment Options ◽  
Left Ventricular ◽  
Primate Model ◽  
Cardiac Tissues ◽  
Mitral Valves ◽  
Intestinal Submucosa ◽  
Post Implantation

Introduction: To investigate enhanced treatment options for critical mitral valve disease in children, we implanted a bio-scaffold mitral valve comprising of porcine small intestinal submucosa (PSIS) in a juvenile baboon model. Hypothesis: New tissue formation would be accelerated at physical connections between the replacement bio-scaffold valve and native cardiac tissues, due to direct extracellular matrix (ECM) communications. Methods: Juvenile baboons (n=2) were implanted with a hand-made bicuspid PSIS (Cormatrix, Roswell, GA) mitral valve. The PSIS valves were excised at 11- and 20-months post-implantation. Images of histological stains (Movat’s Pentachrome; Alizée Pathology, Inc., Thurmont, MD) were subsequently spatially mapped for ECM quantification (MATLAB; Mathworks, Natick, MA). Results: PSIS bio-scaffold mitral valves (11- and 20-months post-implantation) facilitated complete regeneration of neochordae. The neochordae seamlessly integrated into the papillary muscles and left ventricular insertion sites ( Figure 1A, E ). We also found that with an increase in implantation duration of ~ 9 months, the collagen, proteoglycan and elastin content (per mm 2 ; Figure 1B-D, F-H ) had a fold-change of 6.96, 18.42 and 4.94, respectively. Conclusions: Our findings suggest that the PSIS bio-scaffold mitral valve apparatus can regenerate neochordae without the need for any biochemical or biomechanical treatment. Nonetheless, other valve spatial areas of importance (e.g. leaflets) will require additional strategies. As a next step, we will produce oscillatory flow-conditioned, stem cell-derived ECM, to accelerate tissue regeneration. The mechanical parameters that we computed to permit physiological oscillatory flow conditions are an oscillatory shear index (OSI) of 0.23 and time averaged bio-scaffold shear stress (TAB-SSS) of 4.6 dynes/cm 2 . Acknowledgements: AHA Award ID: 16GRNT31090009; The Miami Research Heart Institute; FIU-UGS DYF.

Custom Patient-Specific Three-Dimensional Printed Mitral Valve Models for Pre-Operative Patient Education Enhance Patient Satisfaction and Understanding

2019 ◽  
Vol 13 (3) ◽  
Author(s):  
Kay S. Hung ◽  
Michael J. Paulsen ◽  
Hanjay Wang ◽  
Camille Hironaka ◽  
Y. Joseph Woo
Keyword(s):  
Patient Education ◽  
Mitral Valve ◽  
Three Dimensional ◽  
3D Models ◽  
Patient Specific ◽  
Imaging Data ◽  
Anatomical Models ◽  
Mitral Valves ◽  
Flexible Polymer ◽  
3D Printed

In recent years, advances in medical imaging and three-dimensional (3D) additive manufacturing techniques have increased the use of 3D-printed anatomical models for surgical planning, device design and testing, customization of prostheses, and medical education. Using 3D-printing technology, we generated patient-specific models of mitral valves from their pre-operative cardiac imaging data and utilized these custom models to educate patients about their anatomy, disease, and treatment. Clinical 3D transthoracic and transesophageal echocardiography images were acquired from patients referred for mitral valve repair surgery and segmented using 3D modeling software. Patient-specific mitral valves were 3D-printed using a flexible polymer material to mimic the precise geometry and tissue texture of the relevant anatomy. 3D models were presented to patients at their pre-operative clinic visit and patient education was performed using either the 3D model or the standard anatomic illustrations. Afterward, patients completed questionnaires assessing knowledge and satisfaction. Responses were calculated based on a 1–5 Likert scale and analyzed using a nonparametric Mann–Whitney test. Twelve patients were presented with a patient-specific 3D-printed mitral valve model in addition to standard education materials and twelve patients were presented with only standard educational materials. The mean survey scores were 64.2 (±1.7) and 60.1 (±5.9), respectively (p = 0.008). The use of patient-specific anatomical models positively impacts patient education and satisfaction, and is a feasible method to open new opportunities in precision medicine.

Coaptation Mechanism of Dilated Mitral Valves

2010 ◽  
Author(s):  
Bo Gao ◽  
Zhaoming He
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Left Ventricular Dysfunction ◽  
Ventricular Dysfunction ◽  
Left Ventricular ◽  
Functional Mitral Regurgitation ◽  
Common Complication ◽  
Mitral Valves ◽  
Global Left Ventricular ◽  
Normal Mitral Valve

Functional mitral regurgitation, which occurs as a consequence of regional of global left ventricular or global left ventricular dysfunction despite structurally normal mitral valve (MV), is a common complication in patients with ischemic or non-ischemic cardiomyopathies [1].

Fibrous skeleton reconstruction for invasive aortic and mitral valve endocarditis

2020 ◽  
Vol 28 (7) ◽  
pp. 381-383 ◽  
Author(s):  
Kyle Miletic ◽  
Michael Z Tong
Keyword(s):  
Mitral Valve ◽  
Valve Replacement ◽  
Mitral Valve Replacement ◽  
Pericardial Patch ◽  
Mitral Valves ◽  
Bovine Pericardial Patch

Invasive endocarditis of the aortic and mitral valves with involvement of the intervalvular fibrosa is a particular surgical challenge. We describe a technique for aortic and mitral valve replacement with concomitant reconstruction of the intervalvular fibrosa, utilizing a folded bovine pericardial patch (Commando operation).

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