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El-Nashar H, Sabry M, Tseng YT, Francis N, Latif N, Parker KH, Moore JE, Yacoub MH. Multiscale structure and function of the aortic valve apparatus. Physiol Rev 2024; 104:1487-1532. [PMID: 37732828 DOI: 10.1152/physrev.00038.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 09/22/2023] Open
Abstract
Whereas studying the aortic valve in isolation has facilitated the development of life-saving procedures and technologies, the dynamic interplay of the aortic valve and its surrounding structures is vital to preserving their function across the wide range of conditions encountered in an active lifestyle. Our view is that these structures should be viewed as an integrated functional unit, here referred to as the aortic valve apparatus (AVA). The coupling of the aortic valve and root, left ventricular outflow tract, and blood circulation is crucial for AVA's functions: unidirectional flow out of the left ventricle, coronary perfusion, reservoir function, and support of left ventricular function. In this review, we explore the multiscale biological and physical phenomena that underlie the simultaneous fulfillment of these functions. A brief overview of the tools used to investigate the AVA, such as medical imaging modalities, experimental methods, and computational modeling, specifically fluid-structure interaction (FSI) simulations, is included. Some pathologies affecting the AVA are explored, and insights are provided on treatments and interventions that aim to maintain quality of life. The concepts explained in this article support the idea of AVA being an integrated functional unit and help identify unanswered research questions. Incorporating phenomena through the molecular, micro, meso, and whole tissue scales is crucial for understanding the sophisticated normal functions and diseases of the AVA.
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Affiliation(s)
- Hussam El-Nashar
- Aswan Heart Research Centre, Magdi Yacoub Foundation, Cairo, Egypt
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Malak Sabry
- Aswan Heart Research Centre, Magdi Yacoub Foundation, Cairo, Egypt
- Department of Biomedical Engineering, King's College London, London, United Kingdom
| | - Yuan-Tsan Tseng
- Heart Science Centre, Magdi Yacoub Institute, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Nadine Francis
- Aswan Heart Research Centre, Magdi Yacoub Foundation, Cairo, Egypt
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Najma Latif
- Heart Science Centre, Magdi Yacoub Institute, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Kim H Parker
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - James E Moore
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Magdi H Yacoub
- Aswan Heart Research Centre, Magdi Yacoub Foundation, Cairo, Egypt
- Heart Science Centre, Magdi Yacoub Institute, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
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Morany A, Bardon RG, Lavon K, Hamdan A, Bluestein D, Haj-Ali R. Analysis of fibrocalcific aortic valve stenosis: computational pre-and-post TAVR haemodynamics behaviours. ROYAL SOCIETY OPEN SCIENCE 2024; 11:230905. [PMID: 38384780 PMCID: PMC10878817 DOI: 10.1098/rsos.230905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 01/22/2024] [Indexed: 02/23/2024]
Abstract
Fibro-calcific aortic valve (AV) diseases are characterized by calcium growth or accumulation of fibrosis in the AV tissues. Fibrocalcific aortic stenosis (FAS) rises specifically in females, like calcification-induced aortic stenosis (CAS), may eventually necessitate valve replacement. Fluid-structure-interaction (FSI) computational models for severe CAS and FAS patients were developed using lattice Boltzmann method and multi-scale finite elements (FE). Three parametric AV models were introduced: pathology-free of non-calcified tri-and-bicuspid AVs with healthy collagen fibre network (CFN), a FAS model incorporated a thickened CFN with embedded small calcification volumes, and a CAS model employs healthy CFN with embedded high calcification volumes. The results indicate that the interaction between calcium deposits, adjacent tissue and fibres crucially influences haemodynamics and structural reactions. A fourth model of transcatheter aortic valve replacement (TAVR) post-procedure outcomes was created to study both CAS and FAS. TAVR-CAS had a higher maximum contact pressure and lower anchoring area than TAVR-FAS, making it prone to aortic tissue damage and migration. Finally, although the TAVR-CAS offered a larger opening area, its paravalvular leakage was higher. This may be attributed to a similar thrombogenicity potential characterizing both models. The computational framework emphasizes the significance of mechanobiology in FAS and underscores the requirement for tissue modelling at multiple scales.
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Affiliation(s)
- Adi Morany
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel
| | | | - Karin Lavon
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Ashraf Hamdan
- Department of Cardiology, Rabin Medical Center, Petach Tikva, Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Rami Haj-Ali
- School of Mechanical Engineering, Tel Aviv University, Tel Aviv, Israel
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA
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3
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Cai L, Hao Y, Ma P, Zhu G, Luo X, Gao H. Fluid-structure interaction simulation of calcified aortic valve stenosis. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:13172-13192. [PMID: 36654041 DOI: 10.3934/mbe.2022616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Calcified aortic valve stenosis (CAVS) is caused by calcium buildup and tissue thickening that impede the blood flow from left ventricle (LV) to aorta. In recent years, CAVS has become one of the most common cardiovascular diseases. Therefore, it is necessary to study the mechanics of aortic valve (AV) caused by calcification. In this paper, based on a previous idealized AV model, the hybrid immersed boundary/finite element method (IB/FE) is used to study AV dynamics and hemodynamic performance under normal and calcified conditions. The computational CAVS model is realized by dividing the AV leaflets into a calcified region and a healthy region, and each is described by a specific constitutive equation. Our results show that calcification can significantly affect AV dynamics. For example, the elasticity and mobility of the leaflets decrease due to calcification, leading to a smaller opening area with a high forward jet flow across the valve. The calcified valve also experiences an increase in local stress and strain. The increased loading due to AV stenosis further leads to a significant increase in left ventricular energy loss and transvalvular pressure gradients. The model predicted hemodynamic parameters are in general consistent with the risk classification of AV stenosis in the clinic. Therefore, mathematical models of AV with calcification have the potential to deepen our understanding of AV stenosis-induced ventricular dysfunction and facilitate the development of computational engineering-assisted medical diagnosis in AV related diseases.
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Affiliation(s)
- Li Cai
- School of Mathematics and Statistics, Northwestern Polytechnical University, Xi'an 710129, China
- NPU-UoG International Cooperative Lab for Computation and Application in Cardiology, Xi'an 710129, China
- Xi'an Key Laboratory of Scientific Computation and Applied Statistics, Xi'an 710129, China
| | - Yu Hao
- School of Mathematics and Statistics, Northwestern Polytechnical University, Xi'an 710129, China
- NPU-UoG International Cooperative Lab for Computation and Application in Cardiology, Xi'an 710129, China
- Xi'an Key Laboratory of Scientific Computation and Applied Statistics, Xi'an 710129, China
| | - Pengfei Ma
- School of Mathematics and Statistics, Northwestern Polytechnical University, Xi'an 710129, China
- NPU-UoG International Cooperative Lab for Computation and Application in Cardiology, Xi'an 710129, China
- Xi'an Key Laboratory of Scientific Computation and Applied Statistics, Xi'an 710129, China
| | - Guangyu Zhu
- School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xiaoyu Luo
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Hao Gao
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QQ, UK
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4
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Myasoedova VA, Conte M, Valerio V, Moschetta D, Massaiu I, Petraglia L, Leosco D, Poggio P, Parisi V. Red Flags, Prognostic Impact, and Management of Patients With Cardiac Amyloidosis and Aortic Valve Stenosis: A Systematic Review and Meta-Analysis. Front Med (Lausanne) 2022; 9:858281. [PMID: 35355593 PMCID: PMC8959832 DOI: 10.3389/fmed.2022.858281] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/07/2022] [Indexed: 11/23/2022] Open
Abstract
Background Cardiac amyloidosis (CA) has been recently recognized as a condition frequently associated with aortic stenosis (AS). The aim of this study was to evaluate: the main characteristics of patients with AS with and without CA, the impact of CA on patients with AS mortality, and the effect of different treatment strategies on outcomes of patients with AS with concomitant CA. Materials and Methods A detailed search related to CA in patients with AS and outcomes was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seventeen studies enrolling 1,988 subjects (1,658 AS alone and 330 AS with CA) were included in the qualitative and quantitative analysis of main patients with AS characteristics with and without CA, difference in mortality, and treatment strategy. Results The prevalence of CA resulted in a mean of 15.4% and it was even higher in patients with AS over 80 years old (18.2%). Patients with the dual diagnosis were more often males, had lower body mass index (BMI), were more prone to have low flow, low gradient with reduced left ventricular ejection fraction AS phenotype, had higher E/A and E/e', and greater interventricular septum hypertrophy. Lower Sokolow–Lyon index, higher QRS duration, higher prevalence of right bundle branch block, higher levels of N-terminal pro-brain natriuretic peptide, and high-sensitivity troponin T were significantly associated with CA in patients with AS. Higher overall mortality in the 178 patients with AS + CA in comparison to 1,220 patients with AS alone was observed [odds ratio (OR) 2.25, p = 0.004]. Meta-regression analysis showed that younger age and diabetes were associated with overall mortality in patients with CS with CA (Z-value −3.0, p = 0.003 and Z-value 2.5, p = 0.013, respectively). Finally, patients who underwent surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI) had a similar overall mortality risk, but lower than medication-treated only patients. Conclusion Results from our meta-analysis suggest that several specific clinical, electrocardiographic, and echocardiographic features can be considered “red flags” of CA in patients with AS. CA negatively affects the outcome of patients with AS. Patients with concomitant CA and AS benefit from SAVR or TAVI.
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Affiliation(s)
- Veronika A Myasoedova
- Centro Cardiologico Monzino Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Maddalena Conte
- Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli Federico II, Naples, Italy.,Casa di Cura San Michele, Maddaloni, Italy
| | - Vincenza Valerio
- Centro Cardiologico Monzino Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Donato Moschetta
- Centro Cardiologico Monzino Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.,Dipartimento di Scienze farmacologiche e biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Ilaria Massaiu
- Centro Cardiologico Monzino Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy.,Developmental Biology of the Immune System, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
| | - Laura Petraglia
- Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Dario Leosco
- Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli Federico II, Naples, Italy
| | - Paolo Poggio
- Centro Cardiologico Monzino Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Milan, Italy
| | - Valentina Parisi
- Dipartimento di Scienze Mediche Traslazionali, Università degli Studi di Napoli Federico II, Naples, Italy
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5
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Karnibad M, Sharabi M, Lavon K, Morany A, Hamdan A, Haj-Ali R. The effect of the fibrocalcific pathological process on aortic valve stenosis in female patients: a finite element study. Biomed Phys Eng Express 2022; 8. [PMID: 35120335 DOI: 10.1088/2057-1976/ac5223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 02/04/2022] [Indexed: 11/11/2022]
Abstract
Calcific aortic valve disease (CAVD) is the most common heart valvular disease in the developed world. Most of the relevant research has been sex-blind, ignoring sex-related biological variables and thus under-appreciate sex differences. However, females present pronounced fibrosis for the same aortic stenosis (AS) severity compared with males, who exhibit more calcification. Herein, we present a computational model of fibrocalcific AV, aiming to investigate its effect on AS development. A parametric study was conducted to explore the influence of the total collagen fiber volume and its architecture on the aortic valve area (AVA). Towards that goal, computational models were generated for three females with stenotic AVs and different volumes of calcium. We have tested the influence of fibrosis on various parameters as fiber architecture, fibrosis location, and transvalvular pressure. We found that increased fiber volume with a low calcium volume could actively contribute to AS and reduce the AVA similarly to high calcium volume. Thus, the computed AVAs for our fibrocalcific models were 0.94 and 0.84 cm2and the clinical (Echo) AVAs were 0.82 and 0.8 cm2. For the heavily calcified model, the computed AVA was 0.8 cm2and the clinical AVA was 0.73 cm2. The proposed models demonstrated how collagen thickening influence the fibrocalcific-AS process in female patients. These models can assist in the clinical decision-making process and treatment development in valve therapy for female patients.
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Affiliation(s)
- Maya Karnibad
- Tel Aviv University, School of Mechanical Engineering, Tel Aviv, 69978, ISRAEL
| | - Mirit Sharabi
- Ariel University, Department of Mechanical engineering and Mechatronics, Ariel, 407000, ISRAEL
| | - Karin Lavon
- Tel Aviv University, School of Mechanical Engineering, Tel Aviv, 69978, ISRAEL
| | - Adi Morany
- Tel Aviv University, School of Mechanical Engineering, Tel Aviv, 69978, ISRAEL
| | - Ashraf Hamdan
- Tel Aviv University, Department of Cardiology, Rabin Medical Center, Tel Aviv, 69978, ISRAEL
| | - Rami Haj-Ali
- Tel Aviv University, School of Mechanical Engineering, Tel Aviv, 69978, ISRAEL
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Kusumo KP, Kuriyan K, Vaidyaraman S, Garcia-Munoz S, Shah N, Chachuat B. Probabilistic Framework for Optimal Experimental Campaigns in the Presence of Operational Constraints. REACT CHEM ENG 2022. [DOI: 10.1039/d1re00465d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The predictive capability of any mathematical model is intertwined with the quality of experimental data collected for its calibration. Model-based design of experiments helps compute maximally informative campaigns for model...
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7
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Sadrabadi MS, Eskandari M, Feigenbaum HP, Arzani A. Local and global growth and remodeling in calcific aortic valve disease and aging. J Biomech 2021; 128:110773. [PMID: 34628201 DOI: 10.1016/j.jbiomech.2021.110773] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/31/2021] [Accepted: 09/22/2021] [Indexed: 11/19/2022]
Abstract
Aging and calcific aortic valve disease (CAVD) are the main factors leading to aortic stenosis. Both processes are accompanied by growth and remodeling pathways that play a crucial role in aortic valve pathophysiology. Herein, a computational growth and remodeling (G&R) framework was developed to investigate the effects of aging and calcification on aortic valve dynamics. Particularly, an algorithm was developed to couple the global growth and stiffening of the aortic valve due to aging and the local growth and stiffening due to calcification with the aortic valve transient dynamics. The aortic valve dynamics during baseline were validated with available data in the literature. Subsequently, the changes in aortic valve dynamic patterns during aging and CAVD progression were studied. The results revealed the patterns in geometric orifice area reduction and an increase in the valve stress during local and global growth and remodeling of the aortic valve. The proposed algorithm provides a framework to couple mechanobiology models of disease growth with tissue-scale transient structural mechanics models to study the biomechanical changes during cardiovascular disease growth and aging.
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Affiliation(s)
| | - Mona Eskandari
- Department of Mechanical Engineering, University of California Riverside, Riverside, CA, USA; BREATHE Center at the School of Medicine, University of California Riverside, Riverside, CA, USA; Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | - Heidi P Feigenbaum
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA
| | - Amirhossein Arzani
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA.
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8
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Progressive Calcification in Bicuspid Valves: A Coupled Hemodynamics and Multiscale Structural Computations. Ann Biomed Eng 2021; 49:3310-3322. [PMID: 34708308 DOI: 10.1007/s10439-021-02877-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 10/13/2021] [Indexed: 10/20/2022]
Abstract
Bicuspid aortic valve (BAV) is the most common congenital heart disease. Calcific aortic valve disease (CAVD) accounts for the majority of aortic stenosis (AS) cases. Half of the patients diagnosed with AS have a BAV, which has an accelerated progression rate. This study aims to develop a computational modeling approach of both the calcification progression in BAV, and its biomechanical response incorporating fluid-structure interaction (FSI) simulations during the disease progression. The calcification is patient-specifically reconstructed from Micro-CT images of excised calcified BAV leaflets, and processed with a novel reverse calcification technique that predicts prior states of CAVD using a density-based criterion, resulting in a multilayered calcified structure. Four progressive multilayered calcified BAV models were generated: healthy, mild, moderate, and severe, and were modeled by FSI simulations during the full cardiac cycle. A valve apparatus model, composed of the excised calcified BAV leaflets, was tested in an in-vitro pulse duplicator, to validate the severe model. The healthy model was validated against echocardiography scans. Progressive AS was characterized by higher systolic jet flow velocities (2.08, 2.3, 3.37, and 3.85 m s-1), which induced intense vortices surrounding the jet, coupled with irregular recirculation backflow patterns that elevated viscous shear stresses on the leaflets. This study shed light on the fluid-structure mechanism that drives CAVD progression in BAV patients.
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9
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Vogl BJ, Niemi NR, Griffiths LG, Alkhouli MA, Hatoum H. Impact of calcific aortic valve disease on valve mechanics. Biomech Model Mechanobiol 2021; 21:55-77. [PMID: 34687365 DOI: 10.1007/s10237-021-01527-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 10/07/2021] [Indexed: 10/20/2022]
Abstract
The aortic valve is a highly dynamic structure characterized by a transvalvular flow that is unsteady, pulsatile, and characterized by episodes of forward and reverse flow patterns. Calcific aortic valve disease (CAVD) resulting in compromised valve function and increased pressure overload on the ventricle potentially leading to heart failure if untreated, is the most predominant valve disease. CAVD is a multi-factorial disease involving molecular, tissue and mechanical interactions. In this review, we aim at recapitulating the biomechanical loads on the aortic valve, summarizing the current and most recent research in the field in vitro, in-silico, and in vivo, and offering a clinical perspective on current strategies adopted to mitigate or approach CAVD.
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Affiliation(s)
- Brennan J Vogl
- Biomedical Engineering Department, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA
| | - Nicholas R Niemi
- Biomedical Engineering Department, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA
| | - Leigh G Griffiths
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | | | - Hoda Hatoum
- Biomedical Engineering Department, Michigan Technological University, 1400 Townsend Dr, Houghton, MI, 49931, USA. .,Health Research Institute, Michigan Technological University, Houghton, MI, USA. .,Center of Biocomputing and Digital Health, Michigan Technological University, Houghton, MI, USA.
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10
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A Coupled Multiscale Approach to Modeling Aortic Valve Mechanics in Health and Disease. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11188332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mechano-biological processes in the aortic valve span multiple length scales ranging from the molecular and cell to tissue and organ levels. The valvular interstitial cells residing within the valve cusps sense and actively respond to leaflet tissue deformations caused by the valve opening and closing during the cardiac cycle. Abnormalities in these biomechanical processes are believed to impact the matrix-maintenance function of the valvular interstitial cells, thereby initiating valvular disease processes such as calcific aortic stenosis. Understanding the mechanical behavior of valvular interstitial cells in maintaining tissue homeostasis in response to leaflet tissue deformation is therefore key to understanding the function of the aortic valve in health and disease. In this study, we applied a multiscale computational homogenization technique (also known as “FE2”) to aortic valve leaflet tissue to study the three-dimensional mechanical behavior of the valvular interstitial cells in response to organ-scale mechanical loading. We further considered calcific aortic stenosis with the aim of understanding the likely relationship between the valvular interstitial cell deformations and calcification. We find that the presence of calcified nodules leads to an increased strain profile that drives further growth of calcification.
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11
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Lashkarinia SS, Coban G, Kose B, Salihoglu E, Pekkan K. Computational modeling of vascular growth in patient-specific pulmonary arterial patch reconstructions. J Biomech 2021; 117:110274. [PMID: 33540217 DOI: 10.1016/j.jbiomech.2021.110274] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 01/09/2021] [Accepted: 01/16/2021] [Indexed: 11/15/2022]
Abstract
Recent progress in vascular growth mechanics has involved the use of computational algorithms to address clinical problems with the use of three-dimensional patient specific geometries. The objective of this study is to establish a predictive computational model for the volumetric growth of pulmonary arterial (PA) tissue following complex cardiovascular patch reconstructive surgeries for congenital heart disease patients. For the first time in the literature, the growth mechanics and performance of artificial cardiovascular patches in contact with the growing PA tissue domain is established. An elastic-growing material model was developed in the open source FEBio software suite to first examine the surgical patch reconstruction process for an idealized main PA anatomy as a benchmark model and then for the patient-specific PA of a newborn. Following patch reconstruction, high levels of stress and strain are compensated by growth on the arterial tissue. As this growth progresses, the arterial tissue is predicted to stiffen to limit elastic deformations. We simulated this arterial growth up to the age of 18 years, when somatic growth plateaus. Our research findings show that the non-growing patch material remains in a low strain state throughout the simulation timeline, while experiencing high stress hot-spots. Arterial tissue growth along the surgical stitch lines is triggered mainly due to PA geometry and blood pressure, rather than due to material property differences in the artificial and native tissue. Thus, non-uniform growth patterns are observed along the arterial tissue proximal to the sutured boundaries. This computational approach is effective for the pre-surgical planning of complex patch surgeries to quantify the unbalanced growth of native arteries and artificial non-growing materials to develop optimal patch biomechanics for improved postoperative outcomes.
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Affiliation(s)
| | - Gursan Coban
- Mechanical Engineering, Istinye University, Turkey
| | - Banu Kose
- Biomedical Engineering, Medipol University, Turkey
| | - Ece Salihoglu
- School of Medicine, Istanbul Bilim University, Turkey
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12
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Arora I, Sharma M, Sun LY, Tollefsbol TO. The Epigenetic Link between Polyphenols, Aging and Age-Related Diseases. Genes (Basel) 2020; 11:genes11091094. [PMID: 32962067 PMCID: PMC7565986 DOI: 10.3390/genes11091094] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/15/2020] [Accepted: 09/16/2020] [Indexed: 12/21/2022] Open
Abstract
Aging is a complex process mainly categorized by a decline in tissue, cells and organ function and an increased risk of mortality. Recent studies have provided evidence that suggests a strong association between epigenetic mechanisms throughout an organism’s lifespan and age-related disease progression. Epigenetics is considered an evolving field and regulates the genetic code at several levels. Among these are DNA changes, which include modifications to DNA methylation state, histone changes, which include modifications of methylation, acetylation, ubiquitination and phosphorylation of histones, and non-coding RNA changes. As a result, these epigenetic modifications are vital targets for potential therapeutic interventions against age-related deterioration and disease progression. Dietary polyphenols play a key role in modulating these modifications thereby delaying aging and extending longevity. In this review, we summarize recent advancements linking epigenetics, polyphenols and aging as well as critical findings related to the various dietary polyphenols in different fruits and vegetables. In addition, we cover studies that relate polyphenols and their epigenetic effects to various aging-related diseases such as cardiovascular diseases, neurodegenerative diseases, autoimmune disorders, diabetes, osteoporosis and cancer.
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Affiliation(s)
- Itika Arora
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (I.A.); (M.S.); (L.Y.S.)
| | - Manvi Sharma
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (I.A.); (M.S.); (L.Y.S.)
| | - Liou Y. Sun
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (I.A.); (M.S.); (L.Y.S.)
- Comprehensive Center for Healthy Aging, University of Alabama Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294, USA
| | - Trygve O. Tollefsbol
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA; (I.A.); (M.S.); (L.Y.S.)
- Comprehensive Center for Healthy Aging, University of Alabama Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294, USA
- Comprehensive Cancer Center, University of Alabama Birmingham, 1802 6th Avenue South, Birmingham, AL 35294, USA
- Nutrition Obesity Research Center, University of Alabama Birmingham, 1675 University Boulevard, Birmingham, AL 35294, USA
- Comprehensive Diabetes Center, University of Alabama Birmingham, Birmingham, AL 35294, USA
- Correspondence: ; Tel.: +1-205-934-4573; Fax: +1-205-975-6097
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13
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Myasoedova VA, Di Minno A, Songia P, Massaiu I, Alfieri V, Valerio V, Moschetta D, Andreini D, Alamanni F, Pepi M, Trabattoni D, Poggio P. Sex-specific differences in age-related aortic valve calcium load: A systematic review and meta-analysis. Ageing Res Rev 2020; 61:101077. [PMID: 32334093 DOI: 10.1016/j.arr.2020.101077] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 04/15/2020] [Accepted: 04/18/2020] [Indexed: 11/28/2022]
Abstract
Aging of the aortic valve, characterized by leaflet thickening and loss of extensibility, leads to progressive changes in valve function. These age-related mechanisms have not been evaluated yet in sex-specific calcific aortic valve stenosis (CAVS) onset and progression. Recent studies reported the association between high aortic valve calcification (AVC) load and male gender in patients with CAVS while women present faster progression than men. To evaluate these age- and sex-specific differences, we performed a systematic review and meta-analysis with meta-regression. A systematic search related to AVC measured by computed tomography and gender-specific differences was conducted according to PRISMA guidelines. Seven studies, enrolling 1859 men and 1055 women, were included in the quantitative synthesis. We found a significant difference between men and women both in AVC load and density. AVC load mean difference (MD), between men and women, was 1131 ± 243 AU (p < 0.0001; I2: 96.5 %, p < 0.001), while AVC density MD was 159 ± 20 AU/cm2 (p < 0.0001) without heterogeneity among the studies (I2: 23.5, p = 0.3). Meta-regression analyses showed that AVC load MD positively correlated with age and other cardiovascular risk factors such as diabetes, hypertension, and coronary artery disease presence. Our meta-analysis shows a significant association of incremental AVC load with male gender, regardless of the individual anatomical characteristics and the cardiovascular risk factors. Further studies are needed: i) to clarify if there are different sex-related pathophysiological processes driving the development and the progression of age-related CAVS, and ii) to determine if a sex-specific therapeutic strategy should be applied for CAVS treatment and/or prevention.
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Affiliation(s)
| | - Alessandro Di Minno
- Università deli Studi di Napoli Federico II, Dipartimento di Farmacia, Napoli, Italy
| | | | | | | | - Vincenza Valerio
- Centro Cardiologico Monzino IRCCS, Milan, Italy; Università deli Studi di Napoli Federico II, Dipartimento di Medicina Clinica e Chirurgia, Napoli, Italy
| | - Donato Moschetta
- Centro Cardiologico Monzino IRCCS, Milan, Italy; Università degli Studi di Milano, Dipartimento di Scienze Farmacologiche e Biomolecolari, Milan, Italy
| | - Daniele Andreini
- Centro Cardiologico Monzino IRCCS, Milan, Italy; Università degli Studi di Milano, Dipartimento di Scienze Cliniche e di Comunità, Milan, Italy
| | - Francesco Alamanni
- Centro Cardiologico Monzino IRCCS, Milan, Italy; Università degli Studi di Milano, Dipartimento di Scienze Cliniche e di Comunità, Milan, Italy
| | - Mauro Pepi
- Centro Cardiologico Monzino IRCCS, Milan, Italy
| | | | - Paolo Poggio
- Centro Cardiologico Monzino IRCCS, Milan, Italy.
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14
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A validated computational framework to predict outcomes in TAVI. Sci Rep 2020; 10:9906. [PMID: 32555300 PMCID: PMC7303192 DOI: 10.1038/s41598-020-66899-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/28/2020] [Indexed: 11/08/2022] Open
Abstract
Transcatheter aortic valve implantation (TAVI) still presents complications: paravalvular leakage (PVL) and onset of conduction abnormalities leading to permanent pacemaker implantation. Our aim was testing a validated patient-specific computational framework for prediction of TAVI outcomes and possible complications. Twenty-eight TAVI patients (14 SapienXT and 14 CoreValve) were retrospectively selected. Pre-procedural CT images were post-processed to create 3D patient-specific implantation sites. The procedures were simulated with finite element analysis. Simulations' results were compared against post-procedural clinical fluoroscopy and echocardiography images. The computational model was in good agreement with clinical findings: the overall stent diameter difference was 2.6% and PVL was correctly identified with a post-processing algorithm in 83% of cases. Strains in the implantation site were studied to assess the risk of conduction system disturbance and were found highest in the patient who required pacemaker implantation. This study suggests that computational tool could support safe planning and broadening of TAVI.
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15
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Orzechowska S, Świsłocka R, Lewandowski W. Model of Pathological Collagen Mineralization Based on Spine Ligament Calcification. MATERIALS 2020; 13:ma13092130. [PMID: 32375359 PMCID: PMC7254246 DOI: 10.3390/ma13092130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/25/2020] [Accepted: 04/27/2020] [Indexed: 11/16/2022]
Abstract
The aim of the study was to determine the time of mineral growth in human spine ligaments using a mathematical model. The study was based on our previous research in which the physicochemical analysis and computed microtomography measurements of deposits in ligamenta flava were performed. Hydroxyapatite-like mineral (HAP) constituted the mineral phase in ligament samples, in two samples calcium pyrophosphate dehydrate (CPPD) was confirmed. The micro-damage of collagen fibrils in the soft tissue is the crystallization center. The growth of the mineral nucleus is a result of the calcium ions deposition on the nucleus surface. Considering the calcium ions, the main component of HAP, it is possible to describe the grain growth using a diffusion model. The model calculations showed that the growth time of CPPD grains was ca. a month to 6 years, and for HAP grains >4 years for the young and >5.5 years for the elderly patients. The growth time of minerals with a radius >400 μm was relatively short and impossible to identify by medical imaging techniques. The change of growth rate was the largest for HAP deposits. The mineral growth time can provide valuable information for understanding the calcification mechanism, may be helpful in future experiments, as well as useful in estimating the time of calcification appearance.
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Affiliation(s)
- Sylwia Orzechowska
- M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland
- Correspondence:
| | - Renata Świsłocka
- Department of Chemistry, Biology and Biotechnology, Bialystok University of Technology, 15-351 Białystok, Poland; (R.Ś.); (W.L.)
| | - Włodzimierz Lewandowski
- Department of Chemistry, Biology and Biotechnology, Bialystok University of Technology, 15-351 Białystok, Poland; (R.Ś.); (W.L.)
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16
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Wang Y, Hu YC, Zhou Y, Zhao L, Chen D, Li LL, Jiang L, Zhang ZC, Li SN, Wen SN, Ruan YF, Liu N, Qiao Y, Lv Q, Hu R, Du X, Liu XH, Ma CS, Dong JZ, Bai R. Relationship between coronary artery calcification and calcium deposition in the myocardium. J Int Med Res 2019; 47:2910-2920. [PMID: 31117861 PMCID: PMC6683874 DOI: 10.1177/0300060519848587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Objectives To investigate the relationship between coronary artery calcification and calcium deposition in cardiomyocytes. Methods Patients who underwent valve replacement plus surgical ablation for atrial fibrillation, together with left atrial appendage resection, were included. Coronary artery calcification (CAC) score was evaluated prior to surgery using dual-source computed tomography. Samples of left atrial appendage tissue were collected to analyse the following indicators: calcium deposition, alkaline phosphatase activity, calcium content, protein levels of runt-related transcription factor 2 (Runx2), osteopontin and β-catenin, and mRNA levels of osteopontin, endothelin and ghrelin. Relationships between CAC score and various indicators were analysed by univariate logistic or linear regression. Results Out of tissue from eight patients, CAC score was not correlated with cardiomyocyte calcification (odds ratio [OR] 0.984 and OR 0.983; von Kossa or alizarin red staining, respectively). CAC score showed an inverse linear correlation with Runx2 protein (β = –0.75), but was not correlated with osteopontin (β = –0.52) or β-catenin protein (β = –0.56), mRNA levels of osteopontin, endothelin and ghrelin (β = 0.13, 0.02, and 0.02, respectively), alkaline phosphatase activity (β = 0.56), or calcium content (β = –0.22). Conclusions Coronary artery calcification was not correlated with calcium deposition in cardiomyocytes.
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Affiliation(s)
- Yue Wang
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Yu-Cai Hu
- 2 Department of Cardiology, The First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China
| | - Yuan Zhou
- 3 Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Lei Zhao
- 4 Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Dong Chen
- 5 Department of Pathology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Lin-Ling Li
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Le Jiang
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Zi-Chuan Zhang
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Song-Nan Li
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Song-Nan Wen
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Yan-Fei Ruan
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Nian Liu
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Yan Qiao
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Qiang Lv
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Rong Hu
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Xin Du
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Xiao-Hui Liu
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Chang-Sheng Ma
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Jian-Zeng Dong
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
| | - Rong Bai
- 1 Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, Beijing, China
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17
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Tintut Y, Hsu JJ, Demer LL. Lipoproteins in Cardiovascular Calcification: Potential Targets and Challenges. Front Cardiovasc Med 2018; 5:172. [PMID: 30533416 PMCID: PMC6265366 DOI: 10.3389/fcvm.2018.00172] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 11/08/2018] [Indexed: 12/16/2022] Open
Abstract
Previously considered a degenerative process, cardiovascular calcification is now established as an active process that is regulated in several ways by lipids, phospholipids, and lipoproteins. These compounds serve many of the same functions in vascular and valvular calcification as they do in skeletal bone calcification. Hyperlipidemia leads to accumulation of lipoproteins in the subendothelial space of cardiovascular tissues, which leads to formation of mildly oxidized phospholipids, which are known bioactive factors in vascular cell calcification. One lipoprotein of particular interest is Lp(a), which showed genome-wide significance for the presence of aortic valve calcification and stenosis. It carries an important enzyme, autotaxin, which produces lysophosphatidic acid (LPA), and thus has a key role in inflammation among other functions. Matrix vesicles, extruded from the plasma membrane of cells, are the sites of initiation of mineral formation. Phosphatidylserine, a phospholipid in the membranes of matrix vesicles, is believed to complex with calcium and phosphate ions, creating a nidus for hydroxyapatite crystal formation in cardiovascular as well as in skeletal bone mineralization. This review focuses on the contributions of lipids, phospholipids, lipoproteins, and autotaxin in cardiovascular calcification, and discusses possible therapeutic targets.
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Affiliation(s)
- Yin Tintut
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Physiology, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Orthopaedic Surgery, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jeffrey J Hsu
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Linda L Demer
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Physiology, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States
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18
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Rotman OM, Bianchi M, Ghosh RP, Kovarovic B, Bluestein D. Principles of TAVR valve design, modelling, and testing. Expert Rev Med Devices 2018; 15:771-791. [PMID: 30318937 PMCID: PMC6417919 DOI: 10.1080/17434440.2018.1536427] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
INTRODUCTION Transcatheter aortic valve replacement (TAVR) has emerged as an effective minimally-invasive alternative to surgical valve replacement in medium- to high-risk, elderly patients with calcific aortic valve disease and severe aortic stenosis. The rapid growth of the TAVR devices market has led to a high variety of designs, each aiming to address persistent complications associated with TAVR valves that may hamper the anticipated expansion of TAVR utility. AREAS COVERED Here we outline the challenges and the technical demands that TAVR devices need to address for achieving the desired expansion, and review design aspects of selected, latest generation, TAVR valves of both clinically-used and investigational devices. We further review in detail some of the up-to-date modeling and testing approaches for TAVR, both computationally and experimentally, and additionally discuss those as complementary approaches to the ISO 5840-3 standard. A comprehensive survey of the prior and up-to-date literature was conducted to cover the most pertaining issues and challenges that TAVR technology faces. EXPERT COMMENTARY The expansion of TAVR over SAVR and to new indications seems more promising than ever. With new challenges to come, new TAV design approaches, and materials used, are expected to emerge, and novel testing/modeling methods to be developed.
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Affiliation(s)
- Oren M. Rotman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Matteo Bianchi
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Ram P. Ghosh
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Brandon Kovarovic
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Danny Bluestein
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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19
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Aghasafari P, George U, Pidaparti R. A review of inflammatory mechanism in airway diseases. Inflamm Res 2018; 68:59-74. [PMID: 30306206 DOI: 10.1007/s00011-018-1191-2] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 09/12/2018] [Accepted: 09/27/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Inflammation in the lung is the body's natural response to injury. It acts to remove harmful stimuli such as pathogens, irritants, and damaged cells and initiate the healing process. Acute and chronic pulmonary inflammation are seen in different respiratory diseases such as; acute respiratory distress syndrome, chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis (CF). FINDINGS In this review, we found that inflammatory response in COPD is determined by the activation of epithelial cells and macrophages in the respiratory tract. Epithelial cells and macrophages discharge transforming growth factor-β (TGF-β), which trigger fibroblast proliferation and tissue remodeling. Asthma leads to airway hyper-responsiveness, obstruction, mucus hyper-production, and airway-wall remodeling. Cytokines, allergens, chemokines, and infectious agents are the main stimuli that activate signaling pathways in epithelial cells in asthma. Mutation of the CF transmembrane conductance regulator (CFTR) gene results in CF. Mutations in CFTR influence the lung epithelial innate immune function that leads to exaggerated and ineffective airway inflammation that fails to abolish pulmonary pathogens. We present mechanistic computational models (based on ordinary differential equations, partial differential equations and agent-based models) that have been applied in studying the complex physiological and pathological mechanisms of chronic inflammation in different airway diseases. CONCLUSION The scope of the present review is to explore the inflammatory mechanism in airway diseases and highlight the influence of aging on airways' inflammation mechanism. The main goal of this review is to encourage research collaborations between experimentalist and modelers to promote our understanding of the physiological and pathological mechanisms that control inflammation in different airway diseases.
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Affiliation(s)
| | - Uduak George
- College of Engineering, University of Georgia, Athens, GA, USA.,Department of Mathematics and Statistics, San Diego State University, San Diego, CA, USA
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20
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Halevi R, Hamdan A, Marom G, Lavon K, Ben-Zekry S, Raanani E, Haj-Ali R. A New Growth Model for Aortic Valve Calcification. J Biomech Eng 2018; 140:2682794. [DOI: 10.1115/1.4040338] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Indexed: 11/08/2022]
Abstract
Calcific aortic valve disease (CAVD) is a progressive disease in which minerals accumulate in the tissue of the aortic valve cusps, stiffening them and preventing valve opening and closing. The process of valve calcification was found to be similar to that of bone formation including cell differentiation to osteoblast-like cells. Studies have shown the contribution of high strains to calcification initiation and growth process acceleration. In this paper, a new strain-based calcification growth model is proposed. The model aims to explain the unique shape of the calcification and other disease characteristics. The calcification process was divided into two stages: Calcification initiation and calcification growth. The initiation locations were based on previously published findings and a reverse calcification technique (RCT), which uses computed tomography (CT) scans of patients to reveal the calcification initiation point. The calcification growth process was simulated by a finite element model of one aortic valve cusp loaded with cyclic loading. Similar to Wolff's law, describing bone response to stress, our model uses strains to drive calcification formation. The simulation grows calcification from its initiation point to its full typical stenotic shape. Study results showed that the model was able to reproduce the typical calcification growth pattern and shape, suggesting that strain is the main driving force behind calcification progression. The simulation also sheds light on other disease characteristics, such as calcification growth acceleration as the disease progresses, as well as sensitivity to hypertension.
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Affiliation(s)
- Rotem Halevi
- School of Mechanical Engineering, Tel-Aviv University, Tel Aviv 69978, Israel
| | - Ashraf Hamdan
- Department of Cardiology, Rabin Medical Center, Petach Tikva 4941492, Israel
| | - Gil Marom
- School of Mechanical Engineering, Tel-Aviv University, Tel Aviv 69978, Israel
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794
| | - Karin Lavon
- School of Mechanical Engineering, Tel-Aviv University, Tel Aviv 69978, Israel
| | - Sagit Ben-Zekry
- Echocardiography Laboratory, Chaim Sheba Medical Center, Tel Hashomer 52621, Israel
| | - Ehud Raanani
- Cardiothoracic Surgery Department, Chaim Sheba Medical Center, Tel Hashomer 52621, Israel
| | - Rami Haj-Ali
- School of Mechanical Engineering, The Nathan Cummings Chair in Mechanics, The Fleischman Faculty of Engineering, Tel-Aviv University, Tel Aviv 69978, Israel e-mail:
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21
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Bosi GM, Capelli C, Cheang MH, Delahunty N, Mullen M, Taylor AM, Schievano S. Population-specific material properties of the implantation site for transcatheter aortic valve replacement finite element simulations. J Biomech 2018; 71:236-244. [PMID: 29482928 PMCID: PMC5889787 DOI: 10.1016/j.jbiomech.2018.02.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 02/07/2018] [Accepted: 02/09/2018] [Indexed: 10/31/2022]
Abstract
Patient-specific computational models are an established tool to support device development and test under clinically relevant boundary conditions. Potentially, such models could be used to aid the clinical decision-making process for percutaneous valve selection; however, their adoption in clinical practice is still limited to individual cases. To be fully informative, they should include patient-specific data on both anatomy and mechanics of the implantation site. In this work, fourteen patient-specific computational models for transcatheter aortic valve replacement (TAVR) with balloon-expandable Sapien XT devices were retrospectively developed to tune the material parameters of the implantation site mechanical model for the average TAVR population. Pre-procedural computed tomography (CT) images were post-processed to create the 3D patient-specific anatomy of the implantation site. Balloon valvuloplasty and device deployment were simulated with finite element (FE) analysis. Valve leaflets and aortic root were modelled as linear elastic materials, while calcification as elastoplastic. Material properties were initially selected from literature; then, a statistical analysis was designed to investigate the effect of each implantation site material parameter on the implanted stent diameter and thus identify the combination of material parameters for TAVR patients. These numerical models were validated against clinical data. The comparison between stent diameters measured from post-procedural fluoroscopy images and final computational results showed a mean difference of 2.5 ± 3.9%. Moreover, the numerical model detected the presence of paravalvular leakage (PVL) in 79% of cases, as assessed by post-TAVR echocardiographic examination. The final aim was to increase accuracy and reliability of such computational tools for prospective clinical applications.
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Affiliation(s)
- Giorgia M Bosi
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, London, UK; Cardiovascular Engineering Laboratory, UCL Mechanical Engineering, London, UK.
| | - Claudio Capelli
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, London, UK
| | - Mun Hong Cheang
- Barts Health NHS Trust, University College London Hospital, London, UK
| | - Nicola Delahunty
- Barts Health NHS Trust, University College London Hospital, London, UK
| | - Michael Mullen
- Barts Health NHS Trust, University College London Hospital, London, UK
| | - Andrew M Taylor
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, London, UK
| | - Silvia Schievano
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science & Great Ormond Street Hospital for Children, London, UK
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22
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Arzani A, Mofrad MR. A strain-based finite element model for calcification progression in aortic valves. J Biomech 2017; 65:216-220. [DOI: 10.1016/j.jbiomech.2017.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/12/2017] [Accepted: 10/15/2017] [Indexed: 11/28/2022]
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23
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A numerical study of the hemodynamic effect of the aortic valve on coronary flow. Biomech Model Mechanobiol 2017; 17:319-338. [DOI: 10.1007/s10237-017-0962-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 09/05/2017] [Indexed: 01/09/2023]
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24
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Bakhaty AA, Govindjee S, Mofrad MRK. Consistent trilayer biomechanical modeling of aortic valve leaflet tissue. J Biomech 2017; 61:1-10. [PMID: 28830591 DOI: 10.1016/j.jbiomech.2017.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 05/09/2017] [Accepted: 06/05/2017] [Indexed: 10/19/2022]
Abstract
Aortic valve tissue exhibits highly nonlinear, anisotropic, and heterogeneous material behavior due to its complex microstructure. A thorough understanding of these characteristics permits us to develop numerical models that can shed insight on the function of the aortic valve in health and disease. Herein, we take a closer look at consistently capturing the observed physical response of aortic valve tissue in a continuum mechanics framework. Such a treatment is the first step in developing comprehensive multiscale and multiphysics models. We highlight two important aspects of aortic valve tissue behavior: the role of the collagen fiber microstructure and the native prestressing. We propose a model that captures these two features as well as the heterogeneous layer-scale topology of the tissue. We find the model can reproduce the experimentally observed multiscale mechanical behavior in a manner that provides intuition on the underlying mechanics.
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Affiliation(s)
- Ahmed A Bakhaty
- Departments of Civil & Environmental Engineering and Electrical Engineering & Computer Science, University of California, Berkeley, United States; Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, United States.
| | - Sanjay Govindjee
- Department of Civil & Environmental Engineering, University of California, Berkeley, United States.
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, United States.
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25
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Arzani A, Masters KS, Mofrad MRK. Multiscale Systems Biology Model of Calcific Aortic Valve Disease Progression. ACS Biomater Sci Eng 2017; 3:2922-2933. [DOI: 10.1021/acsbiomaterials.7b00174] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Amirhossein Arzani
- Molecular
Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical
Engineering, University of California, Berkeley, California 94720, United States
| | - Kristyn S. Masters
- Department
of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Mohammad R. K. Mofrad
- Molecular
Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical
Engineering, University of California, Berkeley, California 94720, United States
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26
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Bhattacharya P, Viceconti M. Multiscale modeling methods in biomechanics. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2017; 9:e1375. [PMID: 28102563 PMCID: PMC5412936 DOI: 10.1002/wsbm.1375] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 11/09/2016] [Accepted: 11/17/2016] [Indexed: 01/08/2023]
Abstract
More and more frequently, computational biomechanics deals with problems where the portion of physical reality to be modeled spans over such a large range of spatial and temporal dimensions, that it is impossible to represent it as a single space-time continuum. We are forced to consider multiple space-time continua, each representing the phenomenon of interest at a characteristic space-time scale. Multiscale models describe a complex process across multiple scales, and account for how quantities transform as we move from one scale to another. This review offers a set of definitions for this emerging field, and provides a brief summary of the most recent developments on multiscale modeling in biomechanics. Of all possible perspectives, we chose that of the modeling intent, which vastly affect the nature and the structure of each research activity. To the purpose we organized all papers reviewed in three categories: 'causal confirmation,' where multiscale models are used as materializations of the causation theories; 'predictive accuracy,' where multiscale modeling is aimed to improve the predictive accuracy; and 'determination of effect,' where multiscale modeling is used to model how a change at one scale manifests in an effect at another radically different space-time scale. Consistent with how the volume of computational biomechanics research is distributed across application targets, we extensively reviewed papers targeting the musculoskeletal and the cardiovascular systems, and covered only a few exemplary papers targeting other organ systems. The review shows a research subdomain still in its infancy, where causal confirmation papers remain the most common. WIREs Syst Biol Med 2017, 9:e1375. doi: 10.1002/wsbm.1375 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Pinaki Bhattacharya
- Department of Mechanical Engineering and INSIGNEO Institute for in silico MedicineUniversity of SheffieldSheffieldUK
| | - Marco Viceconti
- Department of Mechanical Engineering and INSIGNEO Institute for in silico MedicineUniversity of SheffieldSheffieldUK
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Zohdi TI. On the biomechanical analysis of the calories expended in a straight boxing jab. J R Soc Interface 2017; 14:rsif.2017.0153. [PMID: 28404871 DOI: 10.1098/rsif.2017.0153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 03/20/2017] [Indexed: 01/15/2023] Open
Abstract
Boxing and related sports activities have become a standard workout regime at many fitness studios worldwide. Oftentimes, people are interested in the calories expended during these workouts. This note focuses on determining the calories in a boxer's jab, using kinematic vector-loop relations and basic work-energy principles. Numerical simulations are undertaken to illustrate the basic model. Multi-limb extensions of the model are also discussed.
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Affiliation(s)
- T I Zohdi
- Department of Mechanical Engineering, University of California, Berkeley, CA 94720-1740, USA
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Assessment of calcified aortic valve leaflet deformations and blood flow dynamics using fluid-structure interaction modeling. INFORMATICS IN MEDICINE UNLOCKED 2017. [DOI: 10.1016/j.imu.2017.09.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Impact of different aortic valve calcification patterns on the outcome of transcatheter aortic valve implantation: A finite element study. J Biomech 2016; 49:2520-30. [PMID: 27059259 PMCID: PMC5038160 DOI: 10.1016/j.jbiomech.2016.03.036] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 03/19/2016] [Indexed: 11/01/2022]
Abstract
Transcatheter aortic valve implantation (TAVI) can treat symptomatic patients with calcific aortic stenosis. However, the severity and distribution of the calcification of valve leaflets can impair the TAVI efficacy. Here we tackle this issue from a biomechanical standpoint, by finite element simulation of a widely adopted balloon-expandable TAVI in three models representing the aortic root with different scenarios of calcific aortic stenosis. We developed a modeling approach realistically accounting for aortic root pressurization and complex anatomy, detailed calcification patterns, and for the actual stent deployment through balloon-expansion. Numerical results highlighted the dependency on the specific calcification pattern of the "dog-boning" of the stent. Also, local stent distortions were associated with leaflet calcifications, and led to localized gaps between the TAVI stent and the aortic tissues, with potential implications in terms of paravalvular leakage. High stresses were found on calcium deposits, which may be a risk factor for stroke; their magnitude and the extent of the affected regions substantially increased for the case of an "arc-shaped" calcification, running from commissure to commissure. Moreover, high stresses due to the interaction between the aortic wall and the leaflet calcifications were computed in the annular region, suggesting an increased risk for annular damage. Our analyses suggest a relation between the alteration of the stresses in the native anatomical components and prosthetic implant with the presence and distribution of relevant calcifications. This alteration is dependent on the patient-specific features of the calcific aortic stenosis and may be a relevant indicator of suboptimal TAVI results.
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Fluid-structure interaction modeling of calcific aortic valve disease using patient-specific three-dimensional calcification scans. Med Biol Eng Comput 2016; 54:1683-1694. [PMID: 26906280 DOI: 10.1007/s11517-016-1458-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/29/2016] [Indexed: 01/08/2023]
Abstract
Calcific aortic valve disease (CAVD) is characterized by calcification accumulation and thickening of the aortic valve cusps, leading to stenosis. The importance of fluid flow shear stress in the initiation and regulation of CAVD progression is well known and has been studied recently using fluid-structure interaction (FSI) models. While cusp calcifications are three-dimensional (3D) masses, previously published FSI models have represented them as either stiffened or thickened two-dimensional (2D) cusps. This study investigates the hemodynamic effect of these calcifications employing FSI models using 3D patient-specific calcification masses. A new reverse calcification technique (RCT) is used for modeling different stages of calcification growth based on the spatial distribution of calcification density. The RCT is applied to generate the 3D calcification deposits reconstructed from a patient-specific CT scans. Our results showed that consideration of 3D calcification deposits led to both higher fluid shear stresses and unique fluid shear stress distribution on the aortic side of the cusps that may have an impact on the calcification growth rate. However, the flow did not seem to affect the geometry of the calcification during the growth phase.
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Hutcheson JD, Goettsch C, Rogers MA, Aikawa E. Revisiting cardiovascular calcification: A multifaceted disease requiring a multidisciplinary approach. Semin Cell Dev Biol 2015; 46:68-77. [PMID: 26358815 DOI: 10.1016/j.semcdb.2015.09.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 09/01/2015] [Accepted: 09/02/2015] [Indexed: 12/24/2022]
Abstract
The presence of cardiovascular calcification significantly predicts patients' morbidity and mortality. Calcific mineral deposition within the soft cardiovascular tissues disrupts the normal biomechanical function of these tissues, leading to complications such as heart failure, myocardial infarction, and stroke. The realization that calcification results from active cellular processes offers hope that therapeutic intervention may prevent or reverse the disease. To this point, however, no clinically viable therapies have emerged. This may be due to the lack of certainty that remains in the mechanisms by which mineral is deposited in cardiovascular tissues. Gaining new insight into this process requires a multidisciplinary approach. The pathological changes in cell phenotype that lead to the physicochemical deposition of mineral and the resultant effects on tissue biomechanics must all be considered when designing strategies to treat cardiovascular calcification. In this review, we overview the current cardiovascular calcification paradigm and discuss emerging techniques that are providing new insight into the mechanisms of ectopic calcification.
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Affiliation(s)
- Joshua D Hutcheson
- Center for Interdisciplinary Cardiovascular Sciences and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States.
| | - Claudia Goettsch
- Center for Interdisciplinary Cardiovascular Sciences and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States
| | - Maximillian A Rogers
- Center for Interdisciplinary Cardiovascular Sciences and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States
| | - Elena Aikawa
- Center for Interdisciplinary Cardiovascular Sciences and Center for Excellence in Vascular Biology, Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, United States.
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Kheradvar A, Groves EM, Falahatpisheh A, Mofrad MK, Hamed Alavi S, Tranquillo R, Dasi LP, Simmons CA, Jane Grande-Allen K, Goergen CJ, Baaijens F, Little SH, Canic S, Griffith B. Emerging Trends in Heart Valve Engineering: Part IV. Computational Modeling and Experimental Studies. Ann Biomed Eng 2015. [PMID: 26224522 DOI: 10.1007/s10439-015-1394-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In this final portion of an extensive review of heart valve engineering, we focus on the computational methods and experimental studies related to heart valves. The discussion begins with a thorough review of computational modeling and the governing equations of fluid and structural interaction. We then move onto multiscale and disease specific modeling. Finally, advanced methods related to in vitro testing of the heart valves are reviewed. This section of the review series is intended to illustrate application of computational methods and experimental studies and their interrelation for studying heart valves.
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Affiliation(s)
- Arash Kheradvar
- Department of Biomedical Engineering, The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, 2410 Engineering Hall, Irvine, CA, 92697-2730, USA. .,Department of Medicine, Division of Cardiology, University of California, Irvine School of Medicine, Irvine, CA, USA.
| | - Elliott M Groves
- Department of Biomedical Engineering, The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, 2410 Engineering Hall, Irvine, CA, 92697-2730, USA.,Department of Medicine, Division of Cardiology, University of California, Irvine School of Medicine, Irvine, CA, USA
| | - Ahmad Falahatpisheh
- Department of Biomedical Engineering, The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, 2410 Engineering Hall, Irvine, CA, 92697-2730, USA
| | - Mohammad K Mofrad
- Department of Bioengineering and Mechanical Engineering, University of California, Berkeley, CA, USA
| | - S Hamed Alavi
- Department of Biomedical Engineering, The Edwards Lifesciences Center for Advanced Cardiovascular Technology, University of California, Irvine, 2410 Engineering Hall, Irvine, CA, 92697-2730, USA
| | - Robert Tranquillo
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Lakshmi P Dasi
- Department of Mechanical Engineering, School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA
| | - Craig A Simmons
- Department of Mechanical & Industrial Engineering, University of Toronto, Toronto, ON, Canada.,Institute of Biomaterials & Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | | | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Frank Baaijens
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Stephen H Little
- Houston Methodist DeBakey Heart & Vascular Center, Houston, TX, USA
| | - Suncica Canic
- Department of Mathematics, University of Houston, Houston, TX, USA
| | - Boyce Griffith
- Department of Mathematics, Center for Interdisciplinary Applied Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,McAllister Heart Institute, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
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Cao K, Bukač M, Sucosky P. Three-dimensional macro-scale assessment of regional and temporal wall shear stress characteristics on aortic valve leaflets. Comput Methods Biomech Biomed Engin 2015; 19:603-13. [PMID: 26155915 DOI: 10.1080/10255842.2015.1052419] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The aortic valve (AV) achieves unidirectional blood flow between the left ventricle and the aorta. Although hemodynamic stresses have been shown to regulate valvular biology, the native wall shear stress (WSS) experienced by AV leaflets remains largely unknown. The objective of this study was to quantify computationally the macro-scale leaflet WSS environment using fluid-structure interaction modeling. An arbitrary Lagrangian-Eulerian approach was implemented to predict valvular flow and leaflet dynamics in a three-dimensional AV geometry subjected to physiologic transvalvular pressure. Local WSS characteristics were quantified in terms of temporal shear magnitude (TSM), oscillatory shear index (OSI) and temporal shear gradient (TSG). The dominant radial WSS predicted on the leaflets exhibited high amplitude and unidirectionality on the ventricularis (TSM>7.50 dyn/cm(2), OSI < 0.17, TSG>325.54 dyn/cm(2) s) but low amplitude and bidirectionality on the fibrosa (TSM < 2.73 dyn/cm(2), OSI>0.38, TSG < 191.17 dyn/cm(2) s). The radial WSS component computed in the leaflet base, belly and tip demonstrated strong regional variability (ventricularis TSM: 7.50-22.32 dyn/cm(2), fibrosa TSM: 1.26-2.73 dyn/cm(2)). While the circumferential WSS exhibited similar spatially dependent magnitude (ventricularis TSM: 1.41-3.40 dyn/cm(2), fibrosa TSM: 0.42-0.76 dyn/cm(2)) and side-specific amplitude (ventricularis TSG: 101.73-184.43 dyn/cm(2) s, fibrosa TSG: 41.92-54.10 dyn/cm(2) s), its temporal variations were consistently bidirectional (OSI>0.25). This study provides new insights into the role played by leaflet-blood flow interactions in valvular function and critical hemodynamic stress data for the assessment of the hemodynamic theory of AV disease.
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Affiliation(s)
- K Cao
- a Department of Aerospace and Mechanical Engineering , University of Notre Dame , Notre Dame , IN , USA
| | - M Bukač
- b Department of Applied and Computational Mathematics and Statistics , University of Notre Dame , Notre Dame , IN , USA
| | - P Sucosky
- a Department of Aerospace and Mechanical Engineering , University of Notre Dame , Notre Dame , IN , USA
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Coupled Simulation of Heart Valves: Applications to Clinical Practice. Ann Biomed Eng 2015; 43:1626-39. [PMID: 26101029 DOI: 10.1007/s10439-015-1348-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 05/26/2015] [Indexed: 12/16/2022]
Abstract
The last few decades have seen great advances in the understanding of heart valves, and consequently, in the development of novel treatment modalities and surgical procedures for valves afflicted by disease. This is due in part to the profound advancements in computing technology and noninvasive medical imaging techniques that have made it possible to numerically model the complex heart valve systems characterized by distinct features at different length scales and various interacting processes. In this article, we highlight the importance of explicitly coupling these multiple scales and diverse processes to accurately simulate the true behavior of the heart valves, in health and disease. We examine some of the computational modeling studies that have a direct consequence on clinical practice.
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36
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Halevi R, Hamdan A, Marom G, Mega M, Raanani E, Haj-Ali R. Progressive aortic valve calcification: Three-dimensional visualization and biomechanical analysis. J Biomech 2015; 48:489-97. [DOI: 10.1016/j.jbiomech.2014.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 10/24/2022]
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37
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Labrosse MR, Beller CJ, Boodhwani M, Hudson C, Sohmer B. Subject-specific finite-element modeling of normal aortic valve biomechanics from 3D+t TEE images. Med Image Anal 2015; 20:162-72. [DOI: 10.1016/j.media.2014.11.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 07/25/2014] [Accepted: 11/07/2014] [Indexed: 01/16/2023]
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Zohdi TI. Mechanically driven accumulation of microscale material at coupled solid-fluid interfaces in biological channels. J R Soc Interface 2014; 11:20130922. [PMID: 24284896 PMCID: PMC3869165 DOI: 10.1098/rsif.2013.0922] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 11/07/2013] [Indexed: 01/15/2023] Open
Abstract
The accumulation of microscale materials at solid-fluid interfaces in biological channels is often the initial stage of certain growth processes, which are present in some forms of atherosclerosis. The objective of this work is to develop a relatively simple model for such accumulation, which researchers can use to qualitatively guide their analyses. Specifically, the approach is to construct rate equations for the accumulation at the solid-fluid interface as a function of the intensity of the shear stress. The accumulation of material subsequently reduces the cross-sectional area of the channel until the fluid-induced shear stress at the solid-fluid interface reaches a critical value, which terminates the accumulation rate. Characteristics of the model are explored analytically and numerically.
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Affiliation(s)
- T. I. Zohdi
- Department of Mechanical Engineering, University of California, 6195 Etcheverry Hall, Berkeley, CA 94720-1740, USA
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39
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Defining the role of fluid shear stress in the expression of early signaling markers for calcific aortic valve disease. PLoS One 2013; 8:e84433. [PMID: 24376809 PMCID: PMC3871675 DOI: 10.1371/journal.pone.0084433] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/22/2013] [Indexed: 12/14/2022] Open
Abstract
Calcific aortic valve disease (CAVD) is an active process presumably triggered by interplays between cardiovascular risk factors, molecular signaling networks and hemodynamic cues. While earlier studies demonstrated that alterations in fluid shear stress (FSS) on the fibrosa could trigger inflammation, the mechanisms of CAVD pathogenesis secondary to side-specific FSS abnormalities are poorly understood. This knowledge could be critical to the elucidation of key CAVD risk factors such as congenital valve defects, aging and hypertension, which are known to generate FSS disturbances. The objective of this study was to characterize ex vivo the contribution of isolated and combined abnormalities in FSS magnitude and frequency to early valvular pathogenesis. The ventricularis and fibrosa of porcine aortic valve leaflets were exposed simultaneously to different combinations of sub-physiologic/physiologic/supra-physiologic levels of FSS magnitude and frequency for 24, 48 and 72 hours in a double cone-and-plate device. Endothelial activation and paracrine signaling were investigated by measuring cell-adhesion molecule (ICAM-1, VCAM-1) and cytokine (BMP-4, TGF-β1) expressions, respectively. Extracellular matrix (ECM) degradation was characterized by measuring the expression and activity of the proteases MMP-2, MMP-9, cathepsin L and cathepsin S. The effect of the FSS treatment yielding the most significant pathological response was examined over a 72-hour period to characterize the time-dependence of FSS mechano-transduction. While cytokine expression was stimulated under elevated FSS magnitude at normal frequency, ECM degradation was stimulated under both elevated FSS magnitude at normal frequency and physiologic FSS magnitude at abnormal frequency. In contrast, combined FSS magnitude and frequency abnormalities essentially maintained valvular homeostasis. The pathological response under supra-physiologic FSS magnitude peaked at 48 hours but was then maintained until the 72-hour time point. This study confirms the sensitivity of valve leaflets to both FSS magnitude and frequency and suggests the ability of supra-physiologic FSS levels or abnormal FSS frequencies to initiate CAVD mechanisms.
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Abstract
The aortic valve is highly responsive to cyclical and continuous mechanical forces, at the macroscopic and cellular levels. In this report, we delineate mechanokinetics (effects of mechanical inputs on the cells) and mechanodynamics (effects of cells and pathologic processes on the mechanics) of the aortic valve, with a particular focus on how mechanical inputs synergize with the inflammatory cytokine and other biomolecular signaling to contribute to the process of aortic valve calcification.
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A metric for the stiffness of calcified aortic valves using a combined computational and experimental approach. Med Biol Eng Comput 2013; 52:1-8. [DOI: 10.1007/s11517-013-1113-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 09/01/2013] [Indexed: 11/25/2022]
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Cuesta S, Kireev R, García C, Rancan L, Vara E, Tresguerres JAF. Melatonin can improve insulin resistance and aging-induced pancreas alterations in senescence-accelerated prone male mice (SAMP8). AGE (DORDRECHT, NETHERLANDS) 2013; 35:659-671. [PMID: 22411259 PMCID: PMC3636397 DOI: 10.1007/s11357-012-9397-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 02/20/2012] [Indexed: 05/31/2023]
Abstract
The aim of the present study was to investigate the effect of aging on several parameters related to glucose homeostasis and insulin resistance in pancreas and how melatonin administration could affect these parameters. Pancreas samples were obtained from two types of male mice models: senescence-accelerated prone (SAMP8) and senescence-accelerated-resistant mice (SAMR1). Insulin levels in plasma were increased with aging in both SAMP8 and SAMR1 mice, whereas insulin content in pancreas was decreased with aging in SAMP8 and increased in SAMR1 mice. Expressions of glucagon and GLUT2 messenger RNAs (mRNAs) were increased with aging in SAMP8 mice, and no differences were observed in somatostatin and insulin mRNA expressions. Furthermore, aging decreased also the expressions of Pdx-1, FoxO 1, FoxO 3A and Sirt1 in pancreatic SAMP8 samples. Pdx-1 was decreased in SAMR1 mice, but no differences were observed in the rest of parameters on these mice strains. Treatment with melatonin was able to decrease plasma insulin levels and to increase its pancreatic content in SAMP8 mice. In SAMR1, insulin pancreatic content and plasma levels were decreased. HOMA-IR was decreased with melatonin treatment in both strains of animals. On the other hand, in SAMP8 mice, treatment decreased the expression of glucagon, GLUT2, somatostatin and insulin mRNA. Furthermore, it was also able to increase the expression of Sirt1, Pdx-1 and FoxO 3A. According to these results, aging is associated with significant alterations in the relative expression of pancreatic genes associated to glucose metabolism. This has been especially observed in SAMP8 mice. Melatonin administration was able to improve pancreatic function in old SAMP8 mice and to reduce HOMA-IR improving their insulin physiology and glucose metabolism.
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Affiliation(s)
- Sara Cuesta
- />Department of Physiology, Medical School, University Complutense of Madrid, Madrid, Spain
| | - Roman Kireev
- />Department of Physiology, Medical School, University Complutense of Madrid, Madrid, Spain
| | - Cruz García
- />Department of Biochemistry and Molecular Biology, Medical School, University Complutense of Madrid, Madrid, Spain
| | - Lisa Rancan
- />Department of Biochemistry and Molecular Biology, Medical School, University Complutense of Madrid, Madrid, Spain
| | - Elena Vara
- />Department of Biochemistry and Molecular Biology, Medical School, University Complutense of Madrid, Madrid, Spain
| | - Jesús A. F. Tresguerres
- />Department of Physiology, Medical School, University Complutense of Madrid, Madrid, Spain
- />Laboratory of Experimental Endocrinology, Department of Physiology, School of Medicine, Complutense University, Avda, Complutense s/n, 28040 Madrid, Spain
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Fisher CI, Chen J, Merryman WD. Calcific nodule morphogenesis by heart valve interstitial cells is strain dependent. Biomech Model Mechanobiol 2012; 12:5-17. [PMID: 22307683 DOI: 10.1007/s10237-012-0377-8] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 01/18/2012] [Indexed: 01/26/2023]
Abstract
Calcific aortic valve disease (CAVD) results in impaired function through the inability of valves to fully open and close, but the causes of this pathology are unknown. Stiffening of the aorta is associated with CAVD and results in exposing the aortic valves to greater mechanical strain. Transforming growth factor β1 (TGF-β1) is enriched in diseased valves and has been shown to combine with strain to synergistically alter aortic valve interstitial cell (AVIC) phenotypes. Therefore, we investigated the role of strain and TGF-β1 on the calcification of AVICs. Following TGF-β1 pretreatment, strain induced intact monolayers to aggregate and calcify. Using a wound assay, we confirmed that TGF-β1 increases tension in the monolayer in parallel with α-smooth muscle actin (αSMA) expression. Continual exposure to strain accelerates aggregates to calcify into mature nodules that contain a necrotic core surrounded by an apoptotic ring. This phenotype appears to be mediated by strain inhibition of AVIC migration after the initial formation of aggregates. To better interpret the extent to which externally applied strain physically impacts this process, we modified the classical Lamé solution, derived using principles from linear elasticity, to reveal strain magnification as a novel feature occurring in a mechanical environment that supports nodule formation. These results indicate that strain can impact multiple points of nodule formation: by modifying tension in the monolayer, remodeling cell contacts, migration, apoptosis, and mineralization. Therefore, strain-induced nodule formation provides new directions for developing strategies to address CAVD.
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Affiliation(s)
- Charles I Fisher
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232-0493, USA
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Weinberg EJ, Mack PJ, Schoen FJ, García-Cardeña G, Kaazempur Mofrad MR. Hemodynamic environments from opposing sides of human aortic valve leaflets evoke distinct endothelial phenotypes in vitro. ACTA ACUST UNITED AC 2011; 10:5-11. [PMID: 20107896 PMCID: PMC2837826 DOI: 10.1007/s10558-009-9089-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The regulation of valvular endothelial phenotypes by the hemodynamic environments of the human aortic valve is poorly understood. The nodular lesions of calcific aortic stenosis (CAS) develop predominantly beneath the aortic surface of the valve leaflets in the valvular fibrosa layer. However, the mechanisms of this regional localization remain poorly characterized. In this study, we combine numerical simulation with in vitro experimentation to investigate the hypothesis that the previously documented differences between valve endothelial phenotypes are linked to distinct hemodynamic environments characteristic of these individual anatomical locations. A finite-element model of the aortic valve was created, describing the dynamic motion of the valve cusps and blood in the valve throughout the cardiac cycle. A fluid mesh with high resolution on the fluid boundary was used to allow accurate computation of the wall shear stresses. This model was used to compute two distinct shear stress waveforms, one for the ventricular surface and one for the aortic surface. These waveforms were then applied experimentally to cultured human endothelial cells and the expression of several pathophysiological relevant genes was assessed. Compared to endothelial cells subjected to shear stress waveforms representative of the aortic face, the endothelial cells subjected to the ventricular waveform showed significantly increased expression of the "atheroprotective" transcription factor Kruppel-like factor 2 (KLF2) and the matricellular protein Nephroblastoma overexpressed (NOV), and suppressed expression of chemokine Monocyte-chemotactic protein-1 (MCP-1). Our observations suggest that the difference in shear stress waveforms between the two sides of the aortic valve leaflet may contribute to the documented differential side-specific gene expression, and may be relevant for the development and progression of CAS and the potential role of endothelial mechanotransduction in this disease.
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Affiliation(s)
- Eli J Weinberg
- Department of Bioengineering, University of California, Berkeley, CA 94720, USA.
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Rausch MK, Bothe W, Kvitting JPE, Göktepe S, Miller DC, Kuhl E. In vivo dynamic strains of the ovine anterior mitral valve leaflet. J Biomech 2011; 44:1149-57. [PMID: 21306716 DOI: 10.1016/j.jbiomech.2011.01.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 11/30/2010] [Accepted: 01/18/2011] [Indexed: 11/19/2022]
Abstract
Understanding the mechanics of the mitral valve is crucial in terms of designing and evaluating medical devices and techniques for mitral valve repair. In the current study we characterize the in vivo strains of the anterior mitral valve leaflet. On cardiopulmonary bypass, we sew miniature markers onto the leaflets of 57 sheep. During the cardiac cycle, the coordinates of these markers are recorded via biplane fluoroscopy. From the resulting four-dimensional data sets, we calculate areal, maximum principal, circumferential, and radial leaflet strains and display their profiles on the averaged leaflet geometry. Average peak areal strains are 13.8±6.3%, maximum principal strains are 13.0±4.7%, circumferential strains are 5.0±2.7%, and radial strains are 7.8±4.3%. Maximum principal strains are largest in the belly region, where they are aligned with the circumferential direction during diastole switching into the radial direction during systole. Circumferential strains are concentrated at the distal portion of the belly region close to the free edge of the leaflet, while radial strains are highest in the center of the leaflet, stretching from the posterior to the anterior commissure. In summary, leaflet strains display significant temporal, regional, and directional variations with largest values inside the belly region and toward the free edge. Characterizing strain distribution profiles might be of particular clinical significance when optimizing mitral valve repair techniques in terms of forces on suture lines and on medical devices.
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Affiliation(s)
- Manuel K Rausch
- Department of Mechanical Engineering, School of Engineering, Stanford University, Stanford, CA 94305, USA
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Butcher JT, Mahler GJ, Hockaday LA. Aortic valve disease and treatment: the need for naturally engineered solutions. Adv Drug Deliv Rev 2011; 63:242-68. [PMID: 21281685 DOI: 10.1016/j.addr.2011.01.008] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/05/2011] [Accepted: 01/14/2011] [Indexed: 01/21/2023]
Abstract
The aortic valve regulates unidirectional flow of oxygenated blood to the myocardium and arterial system. The natural anatomical geometry and microstructural complexity ensures biomechanically and hemodynamically efficient function. The compliant cusps are populated with unique cell phenotypes that continually remodel tissue for long-term durability within an extremely demanding mechanical environment. Alteration from normal valve homeostasis arises from genetic and microenvironmental (mechanical) sources, which lead to congenital and/or premature structural degeneration. Aortic valve stenosis pathobiology shares some features of atherosclerosis, but its final calcification endpoint is distinct. Despite its broad and significant clinical significance, very little is known about the mechanisms of normal valve mechanobiology and mechanisms of disease. This is reflected in the paucity of predictive diagnostic tools, early stage interventional strategies, and stagnation in regenerative medicine innovation. Tissue engineering has unique potential for aortic valve disease therapy, but overcoming current design pitfalls will require even more multidisciplinary effort. This review summarizes the latest advancements in aortic valve research and highlights important future directions.
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Mohammadi H, Mequanint K. Prosthetic aortic heart valves: modeling and design. Med Eng Phys 2010; 33:131-47. [PMID: 20971672 DOI: 10.1016/j.medengphy.2010.09.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 07/19/2010] [Accepted: 09/24/2010] [Indexed: 10/18/2022]
Abstract
Although heart valve replacement is among the most common cardiovascular surgical procedures, their outcome is often difficult to predict. One of the reasons is the design and choice of the materials used for the fabrication of the prostheses. This review paper describes the use of modeling techniques in prosthetic heart valve (HV) design and aims at the justification and development of a polymer based trileaflet mechanical heart valve (MHV). The closing/opening phase behavior of the bileaflet MHV was investigated. The potential problem of valve failure due to crack propagation in the brittle pyrolytic carbon leaflet was also discussed. These studies suggest that although bileaflet MHV performs satisfactorily, there are justifications for improvement. Since the native aortic HV is trileaflet and made of anisotropic and hyperelastic tissue, one possible approach to a better MHV design is based on our ability to closely mimic the natural geometry and biomaterial properties.
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Affiliation(s)
- Hadi Mohammadi
- The Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
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Abstract
Age-associated changes within an individual are inherently complex and occur at multiple levels of organismal function. The overall decline in function of various tissues is known to play a key role in both aging and the complex etiology of certain age-associated diseases such as Alzheimer's disease (AD) and cancer. Continuing research highlights the dynamic capacity of polyphenols to protect against age-associated disorders through a variety of important mechanisms. Numerous lines of evidence suggest that dietary polyphenols such as resveratrol, (-)-epigallocatechin-3-gallate (EGCG), and curcumin have the capacity to mitigate age-associated cellular damage induced via metabolic production of reactive oxygen species (ROS). However, recently acquired evidence also demonstrates a likely role for these polyphenols as anticancer agents capable of preventing formation of new vasculature in neoplastic tissues. Polyphenols have also been shown to possess other anticancer properties such as specific cell-signaling actions that may stimulate the activity of the regulatory protein SIRT1. Additionally, polyphenolic compounds have demonstrated their inhibitory effects against chronic vascular inflammation associated with atherosclerosis. These increasingly well-documented results have begun to provide a basis for considering the use of polyphenols in the development of novel therapies for certain human diseases. And while the mechanisms by which these effects occur are yet to be fully understood, it is evident that further investigation may yield a potential use for polyphenols as pharmacological interventions against specific age-associated diseases.
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Affiliation(s)
- Brannon L Queen
- Department of Biology, University of Alabama at Birmingham, AL 35294, USA
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May-Newman K, Enriquez-Almaguer L, Posuwattanakul P, Dembitsky W. Biomechanics of the Aortic Valve in the Continuous Flow VAD-Assisted Heart. ASAIO J 2010; 56:301-8. [DOI: 10.1097/mat.0b013e3181e321da] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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