scholarly journals Elastin-Dependent Aortic Heart Valve Leaflet Curvature Changes During Cyclic Flexure

2019 ◽  
Vol 6 (2) ◽  
pp. 39 ◽  
Author(s):  
Melake D. Tesfamariam ◽  
Asad M. Mirza ◽  
Daniel Chaparro ◽  
Ahmed Z. Ali ◽  
Rachel Montalvan ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Mean Curvature ◽  
Enzymatic Digestion ◽  
Valve Leaflet ◽  
Calcific Aortic Valve Disease ◽  
Ecm Remodeling ◽  
Elastin Degradation ◽  
Potential Biomarker ◽  
Axial Curvature ◽  
The Mean

The progression of calcific aortic valve disease (CAVD) is characterized by extracellular matrix (ECM) remodeling, leading to structural abnormalities and improper valve function. The focus of the present study was to relate aortic valve leaflet axial curvature changes as a function of elastin degradation, which has been associated with CAVD. Circumferential rectangular strips (L × W = 10 × 2.5 mm) of normal and elastin-degraded (via enzymatic digestion) porcine AV leaflets were subjected to cyclic flexure (1 Hz). A significant increase in mean curvature (p < 0.05) was found in elastin-degraded leaflet specimens in comparison to un-degraded controls at both the semi-constrained (50% of maximum flexed state during specimen bending and straightening events) and fully-constrained (maximally-flexed) states. This significance did not occur in all three flexed configurations when measurements were performed using either minimum or maximum curvature. Moreover, the mean curvature increase in the elastin-degraded leaflets was most pronounced at the instance of maximum flexure, compared to un-degraded controls. We conclude that the mean axial curvature metric can detect distinct spatial changes in aortic valve ECM arising from the loss in bulk content and/or structure of elastin, particularly when there is a high degree of tissue bending. Therefore, the instance of maximum leaflet flexure during the cardiac cycle could be targeted for mean curvature measurements and serve as a potential biomarker for elastin degradation in early CAVD remodeling.

scholarly journals Dissecting Calcific Aortic Valve Disease—The Role, Etiology, and Drivers of Valvular Fibrosis

2021 ◽  
Vol 8 ◽  
Author(s):  
Petra Büttner ◽  
Lukas Feistner ◽  
Philipp Lurz ◽  
Holger Thiele ◽  
Joshua D. Hutcheson ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Aortic Valve ◽  
Aortic Valve Disease ◽  
Molecular Mechanisms ◽  
Left Ventricular ◽  
Valve Disease ◽  
Reverse Remodeling ◽  
Calcific Aortic Valve Disease ◽  
Ecm Remodeling ◽  
The Individual

Calcific aortic valve disease (CAVD) is a highly prevalent and progressive disorder that ultimately causes gradual narrowing of the left ventricular outflow orifice with ensuing devastating hemodynamic effects on the heart. Calcific mineral accumulation is the hallmark pathology defining this process; however, fibrotic extracellular matrix (ECM) remodeling that leads to extensive deposition of fibrous connective tissue and distortion of the valvular microarchitecture similarly has major biomechanical and functional consequences for heart valve function. Significant advances have been made to unravel the complex mechanisms that govern these active, cell-mediated processes, yet the interplay between fibrosis and calcification and the individual contribution to progressive extracellular matrix stiffening require further clarification. Specifically, we discuss (1) the valvular biomechanics and layered ECM composition, (2) patterns in the cellular contribution, temporal onset, and risk factors for valvular fibrosis, (3) imaging valvular fibrosis, (4) biomechanical implications of valvular fibrosis, and (5) molecular mechanisms promoting fibrotic tissue remodeling and the possibility of reverse remodeling. This review explores our current understanding of the cellular and molecular drivers of fibrogenesis and the pathophysiological role of fibrosis in CAVD.

Minimally Invasive Transaortic Repair of the Mitral Valve

2011 ◽  
Vol 14 (4) ◽  
pp. 232 ◽  
Author(s):  
Orlando Santana ◽  
Joseph Lamelas
Keyword(s):  
Mitral Valve ◽  
Aortic Valve ◽  
Mitral Regurgitation ◽  
Aortic Valve Replacement ◽  
Minimally Invasive ◽  
Valve Replacement ◽  
Operative Mortality ◽  
The Mean ◽  
Transaortic Approach

<p><b>Objective:</b> We retrospectively evaluated the results of an edge-to-edge repair (Alfieri stitch) of the mitral valve performed via a transaortic approach in patients who were undergoing minimally invasive aortic valve replacement.</p><p><b>Methods:</b> From January 2010 to September 2010, 6 patients underwent minimally invasive edge-to-edge repair of the mitral valve via a transaortic approach with concomitant aortic valve replacement. The patients were considered to be candidates for this procedure if they were deemed by the surgeon to be high-risk for a double valve procedure and if on preoperative transesophageal echocardiogram the mitral regurgitation jet originated from the middle portion (A2/P2 segments) of the mitral valve.</p><p><b>Results:</b> There was no operative mortality. Mean cardiopulmonary bypass time was 137 minutes, and mean cross-clamp time was 111 minutes. There was a significant improvement in the mean mitral regurgitation grade, with a mean of 3.8 preoperatively and 0.8 postoperatively. The ejection fraction remained stable, with mean preoperative and postoperative ejection fractions of 43.3% and 47.5%, respectively. Follow-up transthoracic echocardiograms obtained at a mean of 33 days postoperatively (range, 8-108 days) showed no significant worsening of mitral regurgitation.</p><p><b>Conclusion:</b> Transaortic repair of the mitral valve is feasible in patients undergoing minimally invasive aortic valve replacement.</p>

scholarly journals Use and success evaluation of percutaneous aortic balloon valvuloplasty in different hemodynamic entities of severe aortic stenosis in the TAVR era

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
K Piayda ◽  
A Wimmer ◽  
H Sievert ◽  
K Hellhammer ◽  
S Afzal ◽  
...  
Keyword(s):  
Heart Failure ◽  
Aortic Valve ◽  
Aortic Stenosis ◽  
Aortic Valve Replacement ◽  
Pressure Gradient ◽  
Severe Aortic Stenosis ◽  
Primary Treatment ◽  
Low Flow ◽  
Mean Pressure ◽  
The Mean

Abstract Background In the era of transcatheter aortic valve replacement (TAVR), there is renewed interest in percutaneous balloon aortic valvuloplasty (BAV), which may qualify as the primary treatment option of choice in special clinical situations. Success of BAV is commonly defined as a significant mean pressure gradient reduction after the procedure. Purpose To evaluate the correlation of the mean pressure gradient reduction and increase in the aortic valve area (AVA) in different flow and gradient patterns of severe aortic stenosis (AS). Methods Consecutive patients from 01/2010 to 03/2018 undergoing BAV were divided into normal-flow high-gradient (NFHG), low-flow low-gradient (LFLG) and paradoxical low-flow low-gradient (pLFLG) AS. Baseline characteristics, hemodynamic and clinical information were collected and compared. Additionally, the clinical pathway of patients (BAV as a stand-alone procedure or BAV as a bridge to aortic valve replacement) was followed-up. Results One-hundred-fifty-six patients were grouped into NFHG (n=68, 43.5%), LFLG (n=68, 43.5%) and pLFLG (n=20, 12.8%) AS. Underlying reasons for BAV and not TAVR/SAVR as the primary treatment option are displayed in Figure 1. Spearman correlation revealed that the mean pressure gradient reduction had a moderate correlation with the increase in the AVA in patients with NFHG AS (r: 0.529, p&lt;0.001) but showed no association in patients with LFLG (r: 0.145, p=0.239) and pLFLG (r: 0.030, p=0.889) AS. Underlying reasons for patients to undergo BAV and not TAVR/SAVR varied between groups, however cardiogenic shock or refractory heart failure (overall 46.8%) were the most common ones. After the procedure, independent of the hemodynamic AS entity, patients showed a functional improvement, represented by substantially lower NYHA class levels (p&lt;0.001), lower NT-pro BNP levels (p=0.003) and a numerical but non-significant improvement in other echocardiographic parameters like the left ventricular ejection fraction (p=0.163) and tricuspid annular plane systolic excursion (TAPSE, p=0.066). An unplanned cardiac re-admission due to heart failure was necessary in 23.7% patients. Less than half of the patients (44.2%) received BAV as a bridge to TAVR/SAVR (median time to bridge 64 days). Survival was significantly increased in patients having BAV as a staged procedure (log-rank p&lt;0.001). Conclusion In daily clinical practice, the mean pressure gradient reduction might be an adequate surrogate of BAV success in patients with NFHG AS but is not suitable for patients with other hemodynamic entities of AS. In those patients, TTE should be directly performed in the catheter laboratory to correctly assess the increase of the AVA. BAV as a staged procedure in selected clinical scenarios increases survival and is a considerable option in all flow states of severe AS. (NCT04053192) Figure 1 Funding Acknowledgement Type of funding source: None

scholarly journals Evogliptin Suppresses Calcific Aortic Valve Disease by Attenuating Inflammation, Fibrosis, and Calcification

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 57
Author(s):  
Bongkun Choi ◽  
Eun-Young Kim ◽  
Ji-Eun Kim ◽  
Soyoon Oh ◽  
Si-On Park ◽  
...  
Keyword(s):  
Animal Models ◽  
Aortic Valve ◽  
Aortic Valve Disease ◽  
Rabbit Model ◽  
Cytokine Expression ◽  
Rate Of Change ◽  
Valve Disease ◽  
High Cholesterol Diet ◽  
Calcific Aortic Valve Disease ◽  
Valvular Calcification

Calcific aortic valve disease (CAVD) accompanies inflammatory cell infiltration, fibrosis, and ultimately calcification of the valve leaflets. We previously demonstrated that dipeptidyl peptidase-4 (DPP-4) is responsible for the progression of aortic valvular calcification in CAVD animal models. As evogliptin, one of the DPP-4 inhibitors displays high specific accumulation in cardiac tissue, we here evaluated its therapeutic potency for attenuating valvular calcification in CAVD animal models. Evogliptin administration markedly reduced calcific deposition accompanied by a reduction in proinflammatory cytokine expression in endothelial nitric oxide synthase-deficient mice in vivo, and significantly ameliorated the mineralization of the primary human valvular interstitial cells (VICs), with a reduction in the mRNA expression of bone-associated and fibrosis-related genes in vitro. In addition, evogliptin ameliorated the rate of change in the transaortic peak velocity and mean pressure gradients in our rabbit model as assessed by echocardiography. Importantly, evogliptin administration in a rabbit model was found to suppress the effects of a high-cholesterol diet and of vitamin D2-driven fibrosis in association with a reduction in macrophage infiltration and calcific deposition in aortic valves. These results have indicated that evogliptin prohibits inflammatory cytokine expression, fibrosis, and calcification in a CAVD animal model, suggesting its potential as a selective therapeutic agent for the inhibition of valvular calcification during CAVD progression.

scholarly journals Evolution of the first eigenvalue of the Laplace operator and the p-Laplace operator under a forced mean curvature flow

2020 ◽  
Vol 18 (1) ◽  
pp. 1518-1530
Author(s):  
Xuesen Qi ◽  
Ximin Liu
Keyword(s):  
Laplace Operator ◽  
Mean Curvature ◽  
Mean Curvature Flow ◽  
Curvature Flow ◽  
Second Fundamental Form ◽  
Coefficient Function ◽  
First Eigenvalue ◽  
Initial Hypersurface ◽  
The Mean ◽  
The Laplace Operator

Abstract In this paper, we discuss the monotonicity of the first nonzero eigenvalue of the Laplace operator and the p-Laplace operator under a forced mean curvature flow (MCF). By imposing conditions associated with the mean curvature of the initial hypersurface and the coefficient function of the forcing term of a forced MCF, and some special pinching conditions on the second fundamental form of the initial hypersurface, we prove that the first nonzero closed eigenvalues of the Laplace operator and the p-Laplace operator are monotonic under the forced MCF, respectively, which partially generalize Mao and Zhao’s work. Moreover, we give an example to specify applications of conclusions obtained above.

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