scholarly journals Modelling and simulation of mitral valve for transapical repair applications

2019 ◽  
Vol 24 (4) ◽  
Author(s):  
Gediminas Gaidulis ◽  
Matteo Selmi ◽  
Diana Diana Zakarkaitė ◽  
Audrius Aidietis ◽  
Rimantas Kačianauskas
Keyword(s):  
Mitral Valve ◽  
Real Life ◽  
Computational Modelling ◽  
Element Model ◽  
Time Frame ◽  
Quantitative Information ◽  
Nonlinear Material ◽  
Patient Specific ◽  
Chordae Tendineae ◽  
Invasive Approach

Development and application of the numerical model for the simulation of human heart mitral valve (MV) transapical repair is presented. Transapical repair with neochordae implantation is a novel surgical technique allowing beating-heart correction of mitral regurgitation caused by chordae tendineae rupture through a minimally-invasive approach. In the present study, the structural finite element model of the MV decoupled from the blood flow is considered. It comprises two leaflets and chordae tendineae described by nonlinear material model. Geometry of the model and kinematic boundary conditions for fixed points of MV annulus, papillary muscles, and left ventricle apex are defined by patient-specific data. Decoupled behavior of blood is specified by the time-dependent physiologic transvalvular pressure. Personalized computational modelling strategy is applied to perform virtual transapical MV repair by positioning neochordae following the real-life surgery procedure executed by surgeons. A transient analysis in time frame between end-diastole and peak systole is conducted to evaluate post-repair MV function. Computational MV simulation and modelling results provide quantitative information about the neochordae contribution to the MV function improvement and present practical value for the surgical planning of transapical MV repair.

scholarly journals Mitral valve finite-element modelling from ultrasound data: a pilot study for a new approach to understand mitral function and clinical scenarios

2008 ◽  
Vol 366 (1879) ◽  
pp. 3411-3434 ◽  
Author(s):  
Emiliano Votta ◽  
Enrico Caiani ◽  
Federico Veronesi ◽  
Monica Soncini ◽  
Franco Maria Montevecchi ◽  
...  
Keyword(s):  
Finite Element ◽  
Mitral Valve ◽  
Computational Modelling ◽  
Element Model ◽  
Normal Function ◽  
Patient Specific ◽  
Healthy Human ◽  
Muscle Dynamics ◽  
Clinical Scenarios

In the current scientific literature, particular attention is dedicated to the study of the mitral valve and to comprehension of the mechanisms that lead to its normal function, as well as those that trigger possible pathological conditions. One of the adopted approaches consists of computational modelling, which allows quantitative analysis of the mechanical behaviour of the valve by means of continuum mechanics theory and numerical techniques. However, none of the currently available models realistically accounts for all of the aspects that characterize the function of the mitral valve. Here, a new computational model of the mitral valve has been developed from in vivo data, as a first step towards the development of patient-specific models for the evaluation of annuloplasty procedures. A structural finite-element model of the mitral valve has been developed to account for all of the main valvular substructures. In particular, it includes the real geometry and the movement of the annulus and papillary muscles, reconstructed from four-dimensional ultrasound data from a healthy human subject, and a realistic description of the complex mechanical properties of mitral tissues. Preliminary simulations allowed mitral valve closure to be realistically mimicked and the role of annulus and papillary muscle dynamics to be quantified.

FINITE ELEMENT MODELING OF THE HUMAN MITRAL VALVE: IMPLICATIONS OF MORPHOLOGIES AND DYNAMICS OF THE ANNULUS AND THE CHORDAE TENDINEAE

2014 ◽  
Vol 14 (04) ◽  
pp. 1450057
Author(s):  
QI ZHONG ◽  
WENHUA ZENG ◽  
XIAOYANG HUANG ◽  
BOLIANG WANG ◽  
MING CAI
Keyword(s):  
Finite Element ◽  
Mitral Valve ◽  
Present Model ◽  
Tensile Force ◽  
Average Diameter ◽  
Element Model ◽  
Chordae Tendineae ◽  
Finite Element Program ◽  
Explicit Finite Element ◽  
Saddle Shape

Objectives: To investigate the influences caused by special morphologies and dynamics of the substructures of mitral valve by the explicit finite element program LS-DYNA. Methods: A new finite element model for the mitral apparatus characterized by layered structure of leaflets tissue, saddle shape and contraction of annulus, an approximately accurate morphology of chordae tendineae was developed. The coaptation length, leaflets stress and strain of the present model were compared with those of two auxiliary models, one with planar annulus and the other with fixed annulus. The tensile function and force distribution of chordae tendineae were analyzed in the models with and without chordae tendineae. Results: The stretch ratios computed by the present model were most closely to the experimental data. The leaflets instantly turned over to the atrial side and larger load was observed in the model without chordae tendineae. Besides, tensile force was highly correlated with average diameter of chordae tendineae (r = 0.965). Conclusion: The saddle shape of annulus benefits valve coaptation and the contraction of annulus could help decrease loads on leaflets and prevent stress concentrating excessively. Chordae tendineae could bear partial loads on the leaflets, and prevent the leaflets to turn over to the side of the atrium and help the valve close successfully.

scholarly journals Flexible and comprehensive patient-specific mitral valve silicone models with chordae tendineae made from 3D-printable molds

2019 ◽  
Vol 14 (7) ◽  
pp. 1177-1186 ◽  
Author(s):  
Sandy Engelhardt ◽  
Simon Sauerzapf ◽  
Bernhard Preim ◽  
Matthias Karck ◽  
Ivo Wolf ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Patient Specific ◽  
Chordae Tendineae

Ethical Issues in the Fast Fashion Industry

2018 ◽  
Vol 9 (8) ◽  
pp. 660-665
Author(s):  
Chi Sheh ◽  
◽  
Peng Chan ◽  
Wen Jun Sim ◽  
◽  
...  
Keyword(s):  
Business Ethics ◽  
Conceptual Model ◽  
Ethical Issues ◽  
Real Life ◽  
Time Frame ◽  
Fashion Industry ◽  
Fast Fashion ◽  
Life Event ◽  
Real Cost ◽  
Literature Reviews

Fast fashion is becoming more and more popular nowadays and this industry is growing rapidly. In order to supply to the big demand of fast fashion clothing, company will need to increase the production of the clothing in shorter time frame. Besides that, to out beat the competitor, company will provide more choices of clothing in cheaper price to the customers. By practicing these actions to increase the business profits, company is behaving unethical to the manufacturer of the cloth. Most consumers are not aware of these ethical issues. This paper is will used and tested the conceptual model of fast fashion business ethics based on literature reviews. The finding from this paper will manifest the “real cost” of a cheap and branded fast fashion clothing and will be supported by real life event that happened. However, after realizing the problems, some company did make some changes and the solutions are stated in the paper as well.

Mitral Re-Repair and Right Coronary Fistula Closure Advantage of Minimally Invasive Approach

2010 ◽  
Vol 5 (6) ◽  
pp. 456-459 ◽  
Author(s):  
Vincenzo Giordano ◽  
Jan G. Grandjean
Keyword(s):  
Mitral Valve ◽  
Right Atrium ◽  
Mild Hypothermia ◽  
Posterior Wall ◽  
Coronary Arteriography ◽  
Coronary Fistula ◽  
Invasive Approach ◽  
Concomitant Procedure ◽  
Echocardiographic Images ◽  
The Right

A 51-year-old man developed severe mitral regurgitation 10 years after previous mitral valve repair; the echocardiographic images showed a remarkable eccentric jet toward posterior wall of left atrium associated with a high degree of pulmonary vein retrograde flow. The coronary arteriography pointed out no pathologic lesions but a coronary fistula from the proximal right coronary to the right atrium. The standard approach was avoided, and a right anterolateral minithoracotomy was chosen, providing an excellent view. Under cardiopulmonary bypass and mild hypothermia, the mitral valve was re-repaired, and a new ring was implanted. After aortic cross-clamp release, the right coronary fistula was closed through the right atrium. The postoperative course was uneventful, and the patient was discharged on the fourth postoperative day. In such a high-risk reintervention and concomitant procedure, we think that this different approach may represent a feasible and reliable alternative.

scholarly journals Biomechanical-Structural Correlation of Chordae tendineae in Animal Models: A Pilot Study

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1678
Author(s):  
Justyn Gach ◽  
Izabela Janus ◽  
Agnieszka Mackiewicz ◽  
Tomasz Klekiel ◽  
Agnieszka Noszczyk-Nowak
Keyword(s):  
Mitral Valve ◽  
Complex Structure ◽  
Future Research ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Histopathological Analysis ◽  
Papillary Muscles ◽  
Chordae Tendineae ◽  
Structural Correlation ◽  
Ring Valve

The mitral valve apparatus is a complex structure consisting of the mitral ring, valve leaflets, papillary muscles and chordae tendineae (CT). The latter are mainly responsible for the mechanical functions of the valve. Our study included investigations of the biomechanical and structural properties of CT collected from canine and porcine hearts, as there are no studies about these properties of canine CT. We performed a static uniaxial tensile test on CT samples and a histopathological analysis in order to examine their microstructure. The results were analyzed to clarify whether the changes in mechanical persistence of chordae tendineae are combined with the alterations in their structure. This study offers clinical insight for future research, allowing for an understanding of the process of chordae tendineae rupture that happens during degenerative mitral valve disease—the most common heart disease in dogs.

scholarly journals Effects of intracorneal ring segments implementation technique and design on corneal biomechanics and keratometry in a personalized computational analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Niksa Mohammadi Bagheri ◽  
Mahmoud Kadkhodaei ◽  
Shiva Pirhadi ◽  
Peiman Mosaddegh
Keyword(s):  
Clinical Data ◽  
Three Dimensional ◽  
Element Model ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Average Error ◽  
Constant Thickness ◽  
Arc Length ◽  
Implementation Techniques ◽  
Von Mises

AbstractThe implementation of intracorneal ring segments (ICRS) is one of the successfully applied refractive operations for the treatment of keratoconus (kc) progression. The different selection of ICRS types along with the surgical implementation techniques can significantly affect surgical outcomes. Thus, this study aimed to investigate the influence of ICRS implementation techniques and design on the postoperative biomechanical state and keratometry results. The clinical data of three patients with different stages and patterns of keratoconus were assessed to develop a three-dimensional (3D) patient-specific finite-element model (FEM) of the keratoconic cornea. For each patient, the exact surgery procedure definitions were interpreted in the step-by-step FEM. Then, seven surgical scenarios, including different ICRS designs (complete and incomplete segment), with two surgical implementation methods (tunnel incision and lamellar pocket cut), were simulated. The pre- and postoperative predicted results of FEM were validated with the corresponding clinical data. For the pre- and postoperative results, the average error of 0.4% and 3.7% for the mean keratometry value ($$\text {K}_{\text{mean}}$$ K mean ) were predicted. Furthermore, the difference in induced flattening effects was negligible for three ICRS types (KeraRing segment with arc-length of 355, 320, and two separate 160) of equal thickness. In contrast, the single and double progressive thickness of KeraRing 160 caused a significantly lower flattening effect compared to the same type with constant thickness. The observations indicated that the greater the segment thickness and arc-length, the lower the induced mean keratometry values. While the application of the tunnel incision method resulted in a lower $$\text {K}_{\text{mean}}$$ K mean value for moderate and advanced KC, the induced maximum Von Mises stress on the postoperative cornea exceeded the induced maximum stress on the cornea more than two to five times compared to the pocket incision and the preoperative state of the cornea. In particular, an asymmetric regional Von Mises stress on the corneal surface was generated with a progressive ICRS thickness. These findings could be an early biomechanical sign for a later corneal instability and ICRS migration. The developed methodology provided a platform to personalize ICRS refractive surgery with regard to the patient’s keratoconus stage in order to facilitate the efficiency and biomechanical stability of the surgery.

scholarly journals The Cat Mandible (II): Manipulation of the Jaw, with a New Prosthesis Proposal, to Avoid Iatrogenic Complications

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 683
Author(s):  
Matilde Lombardero ◽  
Mario López-Lombardero ◽  
Diana Alonso-Peñarando ◽  
María del Mar Yllera
Keyword(s):  
Imaging Techniques ◽  
Recovery Period ◽  
Prosthesis Design ◽  
Patient Specific ◽  
Mandibular Fractures ◽  
Rigid Fixation ◽  
Invasive Approach ◽  
Non Invasive ◽  
Iatrogenic Complications ◽  
Mandibular Body

The cat mandible is relatively small, and its manipulation implies the use of fixing methods and different repair techniques according to its small size to keep its biomechanical functionality intact. Attempts to fix dislocations of the temporomandibular joint should be primarily performed by non-invasive techniques (repositioning the bones and immobilisation), although when this is not possible, a surgical method should be used. Regarding mandibular fractures, these are usually concurrent with other traumatic injuries that, if serious, should be treated first. A non-invasive approach should also first be considered to fix mandibular fractures. When this is impractical, internal rigid fixation methods, such as osteosynthesis plates, should be used. However, it should be taken into account that in the cat mandible, dental roots and the mandibular canal structures occupy most of the volume of the mandibular body, a fact that makes it challenging to apply a plate with fixed screw positions without invading dental roots or neurovascular structures. Therefore, we propose a new prosthesis design that will provide acceptable rigid biomechanical stabilisation, but avoid dental root and neurovascular damage, when fixing simple mandibular body fractures. Future trends will include the use of better diagnostic imaging techniques, a patient-specific prosthesis design and the use of more biocompatible materials to minimise the patient’s recovery period and suffering.

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