Emerging Trends in Heart Valve Engineering: Part II. Novel and Standard Technologies for Aortic Valve Replacement

Kheradvar, Arash; Groves, Elliott M.; Goergen, Craig J.; Alavi, S. Hamed; Tranquillo, Robert T.; Simmons, Craig A.; Dasi, Lakshmi Prasad; Grande-Allen, K. Jane; Mofrad, Mohammad R. K.; Falahatpisheh, Ahmad; Griffith, Boyce E.; Baaijens, Fpt Frank; Little, Stephen H.; Čanić, Sunčica

doi:10.1007/s10439-014-1191-5

Cited by 51 publications

(36 citation statements)

References 84 publications

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“…We believe this study is a first step in analysis of the pathological situations such as in mitral prolapse, myxomatous disease, and other structural AV valve diseases. This may also help in optimizing material properties used in prosthetic or tissue-engineered heart valves (3,4,27).…”

Section: Impact On Tissue-engineered Heart Valvesmentioning

confidence: 99%

Load-dependent extracellular matrix organization in atrioventricular heart valves: differences and similarities

Alavi

Sinha

Steward

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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The extracellular matrix of the atrioventricular (AV) valves' leaflets has a key role in the ability of these valves to properly remodel in response to constantly varying physiological loads. While the loading on mitral and tricuspid valves is significantly different, no information is available on how collagen fibers change their orientation in response to these loads. This study delineates the effect of physiological loading on AV valves' leaflets microstructures using Second Harmonic Generation (SHG) microscopy. Fresh natural porcine tricuspid and mitral valves' leaflets (n = 12/valve type) were cut and prepared for the experiments. Histology and immunohistochemistry were performed to compare the microstructural differences between the valves. The specimens were imaged live during the relaxed, loading, and unloading phases using SHG microscopy. The images were analyzed with Fourier decomposition to mathematically seek changes in collagen fiber orientation. Despite the similarities in both AV valves as seen in the histology and immunohistochemistry data, the microstructural arrangement, especially the collagen fiber distribution and orientation in the stress-free condition, were found to be different. Uniaxial loading was dependent on the arrangement of the fibers in their relaxed mode, which led the fibers to reorient in-line with the load throughout the depth of the mitral leaflet but only to reorient in-line with the load in deeper layers of the tricuspid leaflet. Biaxial loading arranged the fibers in between the two principal axes of the stresses independently from their relaxed states. Unlike previous findings, this study concludes that the AV valves' three-dimensional extracellular fiber arrangement is significantly different in their stress-free and uniaxially loaded states; however, fiber rearrangement in response to the biaxial loading remains similar.

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Section: Impact On Tissue-engineered Heart Valvesmentioning

confidence: 99%

Load-dependent extracellular matrix organization in atrioventricular heart valves: differences and similarities

Alavi

Sinha

Steward

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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“…Figure 1 shows the TAVs that are currently FDA approved for clinical use in the United States. 61 The design features, which most distinguish TAVs from their surgical counterparts -except for suture-less SAVRs- are the lack of a sewing cuff and the presence of a collapsible stent frame that houses the valve leaflets.…”

Section: Introductionmentioning

confidence: 99%

“…61, 65 Major TAVR advantages to the traditional surgical approaches can be summarized as refraining cardiopulmonary bypass, aortic cross-clamping and sternotomy that significantly reduces patients’ morbidity. 49 However, current guidelines do not yet recommend TAVR for patients with intermediate or lower risk for open heart surgery.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, only a handful of FDA-approved transcatheter valves (Figure 1) are being used in elderly aortic stenosis patients. 61 Recently, PARTNER II trial showed that in intermediate-risk patients, second generation Edwards’ SAPIEN system is comparable to SAVR with respect to the primary end point of death or disabling stroke. 72 TAV durability has not yet tested in any of the trials.…”

Section: Introductionmentioning

confidence: 99%

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On the Mechanics of Transcatheter Aortic Valve Replacement

et al. 2016

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Transcatheter aortic valves (TAVs) represent the latest advances in prosthetic heart valve technology. TAVs are truly transformational as they bring the benefit of heart valve replacement to patients that would otherwise not be operated on. Nevertheless, like any new device technology, the high expectations are dampened with growing concerns arising from frequent complications that develop in patients, indicating that the technology is far from being mature. Some of the most common complications that plague current TAV devices include malpositioning, crimp-induced leaflet damage, paravalvular leak, thrombosis, conduction abnormalities and prosthesis-patient mismatch. In this article, we provide an in-depth review of the current state-of-the-art pertaining the mechanics of TAVs while highlighting various studies guiding clinicians, regulatory agencies, and next-generation device designers.

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“…When the leaflets of the heart valves are damaged, they are often replaced with prostheses. In the United States, over 80,000 heart valve transplant operations are performed annually and over 300,000 heart surgery operations worldwide [1,2]. Many of the mechanisms that form the basis of the pathophysiology and progress of heart disease have not yet been fully explored, creating difficulties in the medical therapy development [3,4].…”

Section: Introductionmentioning

confidence: 99%

Effect of Fluid Viscosity on Noise of Bileaflet Prosthetic Heart Valve

Voskoboinick¹,

Redaelli²,

Chertov³

et al. 2017

Research Bulletin of the National Technical University of Ukraine "Kyiv Politechnic Institute"

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Background. Numerical simulation and experimental research have been used as powerful tools to understand and predict the behavior and mechanics of the operation of natural heart valves and their prostheses in natural and pathological conditions. Such studies help to evaluate the effectiveness of the valves, their design and the results of surgical procedures, to diagnose healthy and impaired function of the heart valves. There is an actual problem in creating more reliable methods and tools for the operation diagnostics of mechanical heart valves. Objective. The aim of the research is to investigate the effect of fluid viscosity on the hydroacoustic characteristics of jets that flow from a semi-closed and open mechanical bileaflet heart valve. To study the possibility of using hydroacoustic measuring instruments as diagnostic equipment for determining the working conditions of the bileaflet prosthetic heart valve. Methods. The experimental research was carried out by means of hydroacoustic measurements of the hydrodynamic noise in the near wake of the side and central jets of the glycerin solution and the pure water flow downstream of the prosthetic bileaflet heart valve. Results. The effect of fluid viscosity on the hydroacoustic characteristics of the jets that flow from a semi-closed and open mechanical bileaflet heart valve has been experimentally determined. Integral and spectral characteristics of the hydrodynamic noise of jets of the glycerin solution and the pure water flow downstream of the bileaflet mitral heart valve for different fluid rate were detected. Conclusions. In the stream conditions of pure water, the integral characteristics of the pressure field are lower than in stream conditions of the aqueous glycerin solution. As the glycerin concentration in the solution increases, increase average pressures and especially RMS pressure fluctuations. The spectral levels of the hydrodynamic noise in the near wake of the side jet of the glycerin solution are lower than for water flow in the frequency ranges from 1 to 7-8 Hz and from 100 to 1000 Hz for fluid rate 5 l/min. For higher fluid rates, the spectral components of the hydrodynamic noise in the near wake of the side jet of the glycerin solution of the semi-closed mitral valve are higher than that for the pure water. The greatest difference (1.5-1.8 times) in the spectral levels is observed in the frequency range from 10 to 100 Hz for the fluid rate 15 l/min.

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Emerging Trends in Heart Valve Engineering: Part II. Novel and Standard Technologies for Aortic Valve Replacement

Cited by 51 publications

References 84 publications

Load-dependent extracellular matrix organization in atrioventricular heart valves: differences and similarities

Load-dependent extracellular matrix organization in atrioventricular heart valves: differences and similarities

On the Mechanics of Transcatheter Aortic Valve Replacement

Effect of Fluid Viscosity on Noise of Bileaflet Prosthetic Heart Valve

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