Project description:Objective: By assessing the normal dimensions and the relationship between the aortic root and leaflets in Chinese population, the objective of this three-dimensional computed tomography (3DCT)-based study was to establish a matching reference for leaflets and aortic root for aortic valve (AV) repair. Method: Electrocardiogram-gated multi-detector CT was performed on 168 Chinese participants with a normal aortic valve. Measurements of the aortic annuli and leaflets were obtained. The correlations between and the ratios of the specific root and leaflet measurements were analyzed. The references for the leaflet and root dimensions were suggested based on geometric height (gH) using a linear regression equation. The utility of the ratios was tested with CT images of 15 patients who underwent aortic valve repair. Result: The mean annulus diameter (AD), sino-tubular junction (STJ) diameter, geometric height (gH), effective height (eH), free margin length (FML), commissural height (ComH), inter-commissural distance (ICD), and coaptation height (CH) were 22.4 ± 1.7 mm, 27.3 ± 2, 0.4 mm, 15.5 ± 1.7 mm, 8.9 ± 1.2 mm, 32.0 ± 3.4 mm, 17.9 ± 1.9 mm, 23.1 ± 2.3 mm, and 3.1 ± 0.6 mm, respectively. The gH/AD, FML/ICD, and eH/ComH ratios were 0.69 ± 0.07, 1.38 ± 0.08, and 0.50 ± 0.07, respectively. The gH correlated with all other leaflet and root measurements (P < 0.01), whereas the FML demonstrated a better correlation with ICD compared with gH (R2 = 0.75, and R2 = 0.37, respectively). The FML/ICD and eH/ComH ratios might be used to assess leaflet-root mismatch and post-repair leaflet billowing. Conclusion: The normal aortic valve measurements based on 3DCT revealed a specific relationship between the root and leaflets; and this will guide the development of an objective method of aortic valve repair.
Project description:Objective: Aortic valve (AV) leaflets rely on a precise extracellular matrix (ECM) microarchitecture for appropriate biomechanical performance. The ECM structure is maintained by valvular interstitial cells (VICs), which reside within the leaflets. The presence of pigment produced by a melanocytic population of VICs in mice with dark coats has been generally regarded as a nuisance, as it interferes with histological analysis of the AV leaflets. However, our previous studies have shown that the presence of pigment correlates with increased mechanical stiffness within the leaflets as measured by nanoindentation analyses. In the current study, we seek to better characterize the phenotype of understudied melanocytic VICs, explore the role of these VICs in ECM patterning, and assess the presence of these VICs in human aortic valve tissues. Approach and Results: Immunofluorescence and immunohistochemistry revealed that melanocytes within murine AV leaflets express phenotypic markers of either neuronal or glial cells. These VIC subpopulations exhibited regional patterns that corresponded to the distribution of elastin and glycosaminoglycan ECM proteins, respectively. VICs with neuronal and glial phenotypes were also found in human AV leaflets and showed ECM associations similar to those observed in murine leaflets. A subset of VICs within human AV leaflets also expressed dopachrome tautomerase, a common melanocyte marker. A spontaneous mouse mutant with no aortic valve pigmentation lacked elastic fibers and had reduced elastin gene expression within AV leaflets. A hyperpigmented transgenic mouse exhibited increased AV leaflet elastic fibers and elastin gene expression. Conclusions: Melanocytic VIC subpopulations appear critical for appropriate elastogenesis in mouse AVs, providing new insight into the regulation of AV ECM homeostasis. The identification of a similar VIC population in human AVs suggests conservation across species.
Project description:Calcific aortic valvular disease (CAVD) is characterized by sclerosis of the aortic valve leaflets and recent clinical studies have linked several other risk factors to this disease, including male sex. In this study we examined potential sex-related differences in gene expression profiles between porcine male and female valvular interstitial cells (VICs) to explore possible differences in CAVD propensity on the cellular level. RNA samples from three male and three female healthy porcine aortic valve leaflets (denuded of endothelial cells) were isolated, processed, and hybridized to AffymetrixM-BM-. GeneChip Porcine Genome microarrays according to manufacturerM-bM-^@M-^Ys instructions. Mean expression values of each probe set in the male samples were compared with those in the female samples.
Project description:Calcific aortic valvular disease (CAVD) is characterized by sclerosis of the aortic valve leaflets and recent clinical studies have linked several other risk factors to this disease, including male sex. In this study we examined potential sex-related differences in gene expression profiles between porcine male and female valvular interstitial cells (VICs) to explore possible differences in CAVD propensity on the cellular level.
Project description:In this study, we retrospectively analyzed the outcomes of adults with bicuspid aortic valve (BAV) disease who underwent aortic valve reconstructive surgery (AVRS), consisting of replacement of the diseased BAV with 2 or 3 pericardial leaflets plus fixation of the sinotubular junction for accurate and constant leaflet coaptation. From December 2007 through April 2013, 135 consecutive patients (mean age, 49.2 ± 13.1 yr; 73.3% men) with symptomatic BAV disease underwent AVRS. Raphe was observed in 84 patients (62.2%), and the remaining 51 patients had pure BAV without raphe. A total of 122 patients (90.4%) underwent 3-leaflet reconstruction, and 13 (9.6%) underwent 2-leaflet reconstruction. Concomitant aortic wrapping with an artificial graft was performed in 63 patients (46.7%). There were no in-hospital deaths and 2 late deaths (1.5%); 6 patients (4.4%) needed valve-related reoperation. The 5-year cumulative survival rate was 98% ± 1.5%, and freedom from valve-related reoperation at 5 years was 92.7% ± 3.6%. In the last available echocardiograms, aortic regurgitation was absent or trivial in 116 patients (85.9%), mild in 16 (11.9%), moderate in 2 (1.5%), and severe in one (0.7%). The mean aortic valve gradient was 10.2 ± 4.5 mmHg, and the mean aortic valve orifice area index was 1.3 ± 0.3 cm(2)/m(2). The 3-leaflet technique resulted in lower valve gradients and greater valve areas than did the 2-leaflet technique. Thus, in patients with BAV, AVRS yielded satisfactory early and midterm results with low mortality rates and low reoperation risk after the initial procedure.
Project description:Residual and physiological functional strains in soft tissues are known to play an important role in modulating organ stress distributions. Yet, no known comprehensive information on residual strains exist, or non-invasive techniques to quantify in-vivo deformations for the aortic valve (AV) leaflets. Herein we present a completely non-invasive approach for determining heterogeneous strains - both functional and residual - in semilunar valves and apply it to normal human AV leaflets. Transesophageal 3D echocardiographic (3DE) images of the AV were acquired from open-heart transplant patients, with each AV leaflet excised after heart explant and then imaged in a flattened configuration ex-vivo. Using an established spline parameterization of both 3DE segmentations and digitized ex-vivo images (Aggarwal et al., 2014), surface strains were calculated for deformation between the ex-vivo and three in-vivo configurations: fully open, just-coapted, and fully-loaded. Results indicated that leaflet area increased by an average of 20% from the ex-vivo to in-vivo open states, with a highly heterogeneous strain field. The increase in area from open to just-coapted state was the highest at an average of 25%, while that from just-coapted to fully-loaded remained almost unaltered. Going from the ex-vivo to in-vivo mid-systole configurations, the leaflet area near the basal attachment shrank slightly, whereas the free edge expanded by ~10%. This was accompanied by a 10° -20° shear along the circumferential-radial direction. Moreover, the principal stretches aligned approximately with the circumferential and radial directions for all cases, with the highest stretch being along the radial direction. Collectively, these results indicated that even though the AV did not support any measurable pressure gradient in the just-coapted state, the leaflets were significantly pre-strained with respect to the excised state. Furthermore, the collagen fibers of the leaflet were almost fully recruited in the just-coapted state, making the leaflet very stiff with marginal deformation under full pressure. Lastly, the deformation was always higher in the radial direction and lower along the circumferential one, the latter direction made stiffer by the preferential alignment of collagen fibers. These results provide significant insight into the distribution of residual strains and the in-vivo strains encountered during valve opening and closing in AV leaflets, and will form an important component of the tool that can evaluate valve׳s functional properties in a non-invasive manner.
Project description:Background: Subclinical leaflet thrombosis (SLT) is an important sequela that compromises the durability of the bioprosthetic valve. Objectives: To better determine the effect of SLT in bicuspid aortic valve (BAV), we performed a retrospective assessment of CT-defined SLT in BAV and tricuspid aortic valve (TAV) stenotic patients. Methods: We consecutively collected patients undergoing the TAVR between August 2015 and March 2020 in our center. A total of 170 BAV and 201 TAV cases were enrolled. Multidetector computed tomography was performed within 30 days and at 1-year. Results: Twenty cases in the BAV group and 19 cases in the TAV group had hypoattenuated leaflet thickening (HALT) in 30 days (12.5 vs. 9.9%, p = 0.449), and 52 cases in BAV and 61 cases in TAV had the HALT (34.9 vs. 36.7%, p = 0.733) at 1-year follow-up. The mean aortic gradient (MAG) and effective orifice areas (EOA) values were comparable between the two groups at 30 days (HALT vs. no HALT; 10.8 ± 4.8 vs. 11.3 ± 6.0, p = 0.638; 1.6 ± 0.4 vs. 1.6 ± 0.3, p = 0.724), and still, no difference was observed in the MAG at 1-year (11.5 ± 5.6 vs. 10.6 ± 5.1, p = 0.164). However, the EOA at 1-year was statistically different between the two groups (1.5 ± 0.3 vs. 1.6 ± 0.4, p = 0.004). The multivariate logistic regression analysis demonstrated the anticoagulation and age as independent predictors both in the BAV and TAV groups at 1-year. There was no difference in clinical events between the HALT and no HALT group in relevant to BAV or TAV at 1-year follow-up. Conclusions: The presence of subclinical leaflet thrombosis defined by the CT was comparable between the BAV and TAV in the first year after the TAVR procedure. Age and anticoagulation were the independent predictors of the subclinical leaflet thrombosis at 1 year after the TAVR. There was no difference in relevant clinical events between the BAV and TAV groups at 1-year follow-up.
Project description:Genome wide DNA methylation profiling of ascending aorta tissue samples from normal, aortic dissection and bicuspid aortic valve patients with aortic dilation. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles across more than 450,000 CpGs in ascending aorta samples. Samples included 6 normal donors, 12 patients with aortic dissection and 6 patients with bicuspid aortic valve and dilated aorta.