Is a Knowledge of Surface Topology and Contact Angles Enough to Define the Drop Impact Outcome?

It is well known that a superhydrophobic surface may not be able to repel impacting droplets because of the so-called Cassie-to-Wenzel transition. It has been proven that a critical value of the receding contact angle (θR) exists for the complete rebound of water, recently experimentally measured to be 100° for a large range of impact velocities. On the contrary, in the present work, no rebound was observed when low-surface-tension liquids such as hexadecane (σ = 27.5 mN/m at 25 °C) are concerned, even for very low impact velocities and very high values of θR and low contact angle hysteresis. Therefore, the critical threshold of θR ≈ 100° does not sound acceptable for all liquids and for all hydrophobic surfaces. For the same Weber numbers, a Cassie-to-Wenzel state transition occurs after the impact as a result of the easier penetration of low-surface-tension fluids in the surface structure. Hence, a criterion for the drop rebound of low-surface-tension liquids must consider not only the contact angle values with surfaces but also their surface tension and viscosity. This suggests that, even if it is possible to produce surfaces with enhanced static repellence against oils and organics, generally the realization of synthetic materials with self-cleaning and antisticking abilities in dynamic phenomena, such as spray impact, remains an unsolved task. Moreover, it is demonstrated that the chemistry of the surface, the physicochemical interactions with the liquid drops, and the possible wettability gradient of the surface asperity also play important roles in determining the critical Weber number above which impalement occurs. Therefore, the classical numerical simulations of drop impact on dry surfaces are definitively not able to capture the final outcomes of the impact for all possible fluids if the surface topology and chemistry and/or the wettability gradient in the surface structure are not properly reflected.

Semi-automated quantification of tricuspid valve dynamics and structure in tetralogy of Fallot and hypoplastic left heart syndrome using three-dimensional echocardiography.

Anomalies of the tricuspid valve (TV) are associated with worsened prognosis in congenital heart disease (CHD). Here, we present a descriptive study examining changes in TV morphology in two CHD conditions-repaired tetralogy of Fallot (rTOF) and hypoplastic left heart syndrome (HLSH), using three-dimensional echocardiography. Full volume acquisitions of the TV and right ventricle (RV) were performed from an RV-focused apical view using ECG gating over 2-5 consecutive cardiac cycles using 3D echocardiography, from which TV annulus and leaflet parameters were quantified. A total of 40 rTOF patients (age 14 ± 9.8 years), 40 HLHS patients (age1.0 ± 1.5 years) and 80 age and gender matched controls were included. Among leaflet parameters, antero-posterior and posterior-septal TV coaptation heights were smaller in rTOF (p < 0.001) vs. control. Conversely, only the short-axis TV height was different in HLHS vs. controls (HLHS 1.6 ± 0.4 cm vs. control 1.4 ± 0.3 cm). TV leaflet parameters tended to be larger in HLHS, while leaflet coaptation distances were similar between groups. We demonstrate that 3D echocardiography for assessment of the TV is feasible in rTOF and HLHS patients and identifies unique differences in TV morphology. Future studies should clarify the clinical significance of TV morphology in these patient populations.

Myocardial perfusion: near-automated evaluation from contrast-enhanced MR images obtained at rest and during vasodilator stress.

PURPOSE: To develop and validate a technique for near-automated definition of myocardial regions of interest suitable for perfusion evaluation during vasodilator stress cardiac magnetic resonance (MR) imaging. MATERIALS AND METHODS: The institutional review board approved the study protocol, and all patients provided informed consent. Image noise density distribution was used as a basis for endocardial and epicardial border detection combined with nonrigid registration. This method was tested in 42 patients undergoing contrast material-enhanced cardiac MR imaging (at 1.5 T) at rest and during vasodilator (adenosine or regadenoson) stress, including 15 subjects with normal myocardial perfusion and 27 patients referred for coronary angiography. Contrast enhancement-time curves were near-automatically generated and were used to calculate perfusion indexes. The results were compared with results of conventional manual analysis, using quantitative coronary angiography results as a reference for stenosis greater than 50%. Statistical analyses included the Student t test, linear regression, Bland-Altman analysis, and κ statistics. RESULTS: Analysis of one sequence required less than 1 minute and resulted in high-quality contrast enhancement curves both at rest and stress (mean signal-to-noise ratios, 17±7 [standard deviation] and 22±8, respectively), showing expected patterns of first-pass perfusion. Perfusion indexes accurately depicted stress-induced hyperemia (increased upslope, from 6.7 sec(-1)±2.3 to 15.6 sec(-1)±5.9; P<.0001). Measured segmental pixel intensities correlated highly with results of manual analysis (r=0.95). The derived perfusion indexes also correlated highly with (r up to 0.94) and showed the same diagnostic accuracy as manual analysis (area under the receiver operating characteristic curve, up to 0.72 vs 0.73). CONCLUSION: Despite the dynamic nature of contrast-enhanced image sequences and respiratory motion, fast near-automated detection of myocardial segments and accurate quantification of tissue contrast is feasible at rest and during vasodilator stress. This technique, shown to be as accurate as conventional manual analysis, allows detection of stress-induced perfusion abnormalities.

Automatic alignment of standard views for transesophageal echocardiographic images.

Purpose: 3D transesophageal echocardiography (TEE) has become an important modality for pre- and peri-operative imaging of valvular heart disease. TEE can give excellent visualization of valve morphology in 3D rendering. As a convention, 3D TEE images are reformatted in three standard views. We describe a method for automatic calculation of parameters needed to define the standard views from 3D TEE images using no manual input. Approach: An algorithm was designed to find the center of the mitral valve and the left ventricular outflow tract (OT). These parameters defined the three-chamber view. The problem was modeled as a state estimation problem in which a 3D model was deformed based on shape priors and edge detection using a Kalman filter. This algorithm is capable of running in real time after initialization. Results: The algorithm was validated by comparing the automatic alignments of 106 TEE images against manually placed landmarks. The median error for determining the mitral valve center was 7.1 mm, and the median error for determining the left ventricular OT orientation was 13.5 deg. Conclusion: The algorithm is an accurate tool for automating the process of finding standard views for TEE images of the mitral valve.

Quantification of mitral annulus dynamic morphology in patients with mitral valve prolapse undergoing repair and annuloplasty during a 6-month follow-up.

AIMS: Mitral valve (MV) repair is the preferred treatment for mitral regurgitation associated with organic MV prolapse (MVP). Our goals were to describe by transthoracic real-time 3D echocardiography (RT3D TTE) the pre-operative changes in mitral annulus (MA) dynamic morphology related to MVP, compared with a normal population, and to evaluate the differential long-term effects induced by annuloplasty, using either an incomplete flexible band or a complete semi-rigid ring. METHODS AND RESULTS: Forty-four patients (62 ± 11 years) with organic MVP and ejection fraction >55% were studied by RT3D TTE the day before MV repair, and 3 and 6 months after (23 patients received a complete rigid ring-CAR, 21 an incomplete flexible band-COS). An age-matched group of 20 normal subjects (57 ± 9 years) was studied as control. After initialization, the MA was tracked frame-by-frame in 3D, and several parameters computed. Differences in MVP vs. controls, vs. pre-surgery, and between rings were tested (P < 0.05). MVP showed enlarged MA resulting in greater area and height during the cardiac cycle, with reduced planarity compared with controls. Annuloplasty resulted in reduced MA area in both CAR and COS, with minimal area change, and planar shape (more evident in CAR than COS). CONCLUSION: The main factor affecting MA function after annuloplasty appears to be the undersizing of the MA dimensions, and not the choice of the ring. This methodology could represent the basis for further evaluation of implanted rings, to provide the surgeon with additional information to be used in the pre-surgical planning and ring selection.

Right atrial volume is a major determinant of tricuspid annulus area in functional tricuspid regurgitation: a three-dimensional echocardiographic study.

AIMS: The aim of this study is to explore the relationships of tricuspid annulus area (TAA) with right atrial maximal volume (RAVmax) and right ventricular end-diastolic volume (RVEDV) in healthy subjects and patients with functional tricuspid regurgitation (FTR) of different aetiologies and severities. METHODS AND RESULTS: We enrolled 280 patients (median age 66 years, 59% women) with FTR due to left heart disease (LHD), pulmonary hypertension (PH), corrected tetralogy of Fallot (TOF), chronic atrial fibrillation (AF), and 210 healthy volunteers (45 years, 53% women). We measured TAA at mid-systole and end-diastole, tenting volume of tricuspid leaflets, RAVmax, and RVEDV by 3D echocardiography. Irrespective of TA measurement timing, TAA correlated more closely with RAVmax than with RVEDV in both controls and FTR patients. On multivariable analysis, RAVmax was the most important determinant of TAA, accounting for 41% (normals) and 56% (FTR) of TAA variance. In FTR patients, age, RVEDV, and left ventricular ejection fraction were also independently correlated with TAA. RAVmax (AUC = 0.81) and TAA (AUC = 0.78) had a greater ability than RVEDV (AUC = 0.72) to predict severe FTR (P < 0.05). Among FTR patients, those with AF had the largest RAVmax and smallest RVEDV. RAVmax and TA were significantly dilated in all FTR groups, except in TOF. PH and TOF had largest RVEDV, yet tenting volume was increased only in PH and LHD. CONCLUSION: RA volume is a major determinant of TAA, and RA enlargement is an important mechanism of TA dilation in FTR irrespective of cardiac rhythm and RV loading conditions.

Volumetric quantification of myocardial perfusion using analysis of multi-detector computed tomography 3D datasets: comparison with nuclear perfusion imaging.

BACKGROUND: Although the ability of multi-detector computed tomography (MDCT) to detect perfusion abnormalities associated with acute and chronic myocardial infarction (MI) has been demonstrated, this methodology is based on visual interpretation of selected 2D slices. OBJECTIVES: We sought to develop a new technique for quantitative volumetric analysis of myocardial perfusion from 3D datasets and test it against resting nuclear myocardial perfusion imaging (NMPI) reference. METHODS: We studied 44 patients undergoing CTCA: a control group of 15 patients and a study group of 29 patients. MDCT datasets acquired for CTCA were analyzed using custom software designed to: (1) generate bull's eye display of myocardial perfusion and (2) calculate a quantitative index of extent and severity of perfusion abnormality, Q(H), for 16 volumetric myocardial segments. Visual interpretation of MDCT-derived bull's eyes was compared with rest NMPI scores using kappa statistics of agreement on a coronary territory and patient basis. Quantitative MDCT perfusion data were correlated with rest NMPI summed scores and used for objective detection of perfusion defects. RESULTS: Visual analysis of MDCT-derived bull's eyes accurately detected perfusion defects in agreement with NMPI (kappa = 0.70 by territory; 0.79 by patient). Quantitative data were in good agreement with NMPI, as reflected by: (1) correlation of 0.87 (territory) and 0.84 (patient) between summed Q(H) and NMPI scores, (2) area under ROC curve 0.87 with sensitivity of 0.79-0.92, specificity 0.83-0.91, and accuracy 0.83-0.89 for objective detection of abnormalities. CONCLUSIONS: Our new technique for volumetric analysis of 3D MDCT images allows accurate objective detection of perfusion defects. This perfusion information can be obtained without additional radiation or contrast load, and may aid in elucidating the significance of coronary lesions.

Mitral Annulus Segmentation Using Deep Learning in 3-D Transesophageal Echocardiography.

3D Transesophageal Echocardiography is an excellent tool for evaluating the mitral valve and is also well suited for guiding cardiac interventions. We introduce a fully automatic method for mitral annulus segmentation in 3D Transesophageal Echocardiography, which requires no manual input. One hundred eleven multi-frame 3D transesophageal echocardiography recordings were split into training, validation, and test sets. Each 3D recording was decomposed into a set of 2D planes, exploiting the symmetry around the centerline of the left ventricle. A deep 2D convolutional neural network was trained to predict the mitral annulus coordinates, and the predictions from neighboring planes were regularized by enforcing continuity around the annulus. Applying the final model and post-processing to the test set data gave a mean error of 2.0 mm - with a standard deviation of 1.9 mm. Fully automatic segmentation of the mitral annulus can alleviate the need for manual interaction in the quantification of an array of mitral annular parameters and has the potential to eliminate inter-observer variability.

Three-dimensional echocardiography investigation of the mechanisms of tricuspid annular dilatation.

Tricuspid annular (TA) size, assessed by 2D transthoracic echocardiography (TTE), has a well-established prognostic value in patients undergoing mitral valve surgery, with TA dilatation triggering simultaneous tricuspid annuloplasty. While TA dilatation is common in patients with dilated atria secondary to atrial fibrillation, little is known about the mechanisms of TA dilatation in patients with sinus rhythm (SR). This study aimed to identify echocardiographic parameters most closely related to the TA size as a potential tool for identification of patients prone to developing TA enlargement. 120 patients with SR underwent clinically indicated TTE, including 30 patients with normal hearts and 90 patients diagnosed with at least one right heart abnormality, defined as: right ventricular (RV) or right atrial (RA) dilatation, ≥ moderate tricuspid regurgitation (TR) and elevated systolic pulmonary artery pressure (sPAP). RA and RV end-diastolic and end-systolic volumes (EDV, ESV) and function were measured using commercial 3D software (TomTec). 3D RV long and short axes were used as surrogate indices of RV shape. Degrees of TR and sPAP were estimated by 2D TTE. 3D TA sizing was performed at end-diastole using 3D custom software. Linear regression analysis was used to identify variables best correlated with TA size, followed by multivariate analysis to identify independent associations. The highest correlations were found between TA area and: RA ESV (r = 0.73; p < 0.01), RV EDV (r = 0.58; p < 0.01), RV end-diastolic long and short axes (r = 0.53, 0.42; both p < 0.01), TR degree (r = 0.40; p < 0.01) and sPAP (r = 0.32; p < 0.01). Multivariate analysis revealed that RA ESV was the only parameter independently associated with TA area (p < 0.05, r = 0.85). In conclusion, RA volume plays an important role in TA dilatation even in patients with normal SR. Understanding of annular remodeling mechanisms could aid in identifying patients at higher risk for TA dilatation, especially those scheduled for mitral valve surgery.

Semi-automated analysis of dynamic changes in myocardial contrast from real-time three-dimensional echocardiographic images as a basis for volumetric quantification of myocardial perfusion.

AIMS: Despite the potential of real-time three-dimensional (3D) echocardiography (RT3DE) to assess myocardial perfusion, there is no quantification method available for perfusion analysis from RT3DE images. Such method would require 3D regions of interest (ROI) to be defined and adjusted frame-by-frame to compensate for cardiac translation and deformation. Our aims were to develop and test a technique for automated identification of 3D myocardial ROI suitable for translation-free quantification of myocardial videointensity over time, MVI(t), from contrast-enhanced RT3DE images. METHODS AND RESULTS: Twelve transthoracic RT3DE (Philips) data sets obtained in pigs during transition from no contrast to steady-state enhancement (Definity) were analysed using custom software. Analysis included: (i) semi-automated detection of left ventricular endo- and epicardial surfaces using level-set techniques in one frame to define a 3D myocardial ROI, (ii) rigid 3D registration to reduce translation and rotation, (iii) elastic 3D registration to compensate for deformation, and (iv) quantification of MVI(t) in the 3D ROI from the registered and non-registered data sets to assess the effectiveness of registration. For each MVI(t) curve we computed % variability during steady-state enhancement (100 x SD/mean) and goodness of fit (r2) to the indicator dilution equation MVI(t) = A[1-exp(-betat)]. Analysis of myocardial contrast throughout contrast inflow was feasible in all data sets. Three-dimensional registration improved MVI(t) curves in terms of both % variability (2.8 +/- 1.8 to 1.5 +/- 0.9%; P < 0.05) and goodness of fit (r2 from 0.79 +/- 0.2 to 0.90 +/- 0.1; P < 0.05). CONCLUSION: This is the first study to describe a new technique for semi-automated volumetric quantification of myocardial contrast from RT3DE images that includes registration and thus provides the basis for 3D measurement of myocardial perfusion.

Amphiphobic Nanostructured Coatings for Industrial Applications.

The search for surfaces with non-wetting behavior towards water and low-surface tension liquids affects a wide range of industries. Surface wetting is regulated by morphological and chemical features interacting with liquid phases under different ambient conditions. Most of the approaches to the fabrication of liquid-repellent surfaces are inspired by living organisms and require the fabrication of hierarchically organized structures, coupled with low surface energy chemical composition. This paper deals with the design of amphiphobic metals (AM) and alloys by deposition of nano-oxides suspensions in alcoholic or aqueous media, coupled with perfluorinated compounds and optional infused lubricant liquids resulting in, respectively, solid⁻liquid⁻air and solid⁻liquid⁻liquid working interfaces. Nanostructured organic/inorganic hybrid coatings with contact angles against water above 170°, contact angle with n-hexadecane (surface tension γ = 27 mN/m at 20 °C) in the 140⁻150° range and contact angle hysteresis lower than 5° have been produced. A full characterization of surface chemistry has been undertaken by X-ray photoelectron spectroscopy (XPS) analyses, while field-emission scanning electron microscope (FE-SEM) observations allowed the estimation of coatings thicknesses (300⁻400 nm) and their morphological features. The durability of fabricated amphiphobic surfaces was also assessed with a wide range of tests that showed their remarkable resistance to chemically aggressive environments, mechanical stresses and ultraviolet (UV) radiation. Moreover, this work analyzes the behavior of amphiphobic surfaces in terms of anti-soiling, snow-repellent and friction-reduction properties-all originated from their non-wetting behavior. The achieved results make AM materials viable solutions to be applied in different sectors answering several and pressing technical needs.

Echocardiographic Assessment of the Tricuspid Annulus: The Effects of the Third Dimension and Measurement Methodology.

BACKGROUND: Evaluation of the tricuspid annulus is crucial for the decision making at the time of left heart surgery. Current recommendations for tricuspid valve repair are based on two-dimensional (2D) transthoracic echocardiography (TTE), despite the known underestimation compared with three-dimensional (3D) echocardiography. However, little is known about the differences in 3D tricuspid annular (TA) sizing using TTE versus transesophageal echocardiography (TEE). The aims of this study were to (1) compare 2D and 3D TA measurements performed with both TTE and TEE and (2) compare two 3D methods for TA measurements: multiplanar reconstruction (MPR) and dedicated software (DS) designed to take into account TA nonplanarity. METHODS: Seventy patients underwent 2D and 3D TTE and TEE. Two-dimensional images were used to measure TA diameter from apical four-chamber, right ventricular-focused (TTE), and midesophageal four-chamber (TEE) views. Three-dimensional full-volume data sets were analyzed using both MPR and DS, to obtain major and minor axes, perimeter, and area. Intertechnique agreement was assessed using Bland-Altman analysis. RESULTS: Measurements on 2D TTE and TEE, which were view dependent, underestimated TA major dimensions in all views compared with 3D values, irrespective of the 3D method. MPR and DS measurements were significantly different, with DS resulting in larger values for all parameters, irrespective of approach. No differences were found between 3D TTE and 3D TEE for both MPR and DS. CONCLUSIONS: Our findings highlight the need for methodology that respects the 3D geometry of the tricuspid annulus, including its nonplanarity, which cannot be accurately assessed from 2D images and is not equally taken into account by different 3D measurement methodologies. Accordingly, a 3D cutoff value for TA enlargement needs to be established and is likely to be larger than the guideline-recommended 2D-based 40-mm cutoff. Importantly, noninvasive 3D TTE can be used instead of 3D TEE because TA measurements are not different.

3-Dimensional Echocardiographic Analysis of the Tricuspid Annulus Provides New Insights Into Tricuspid Valve Geometry and Dynamics.

OBJECTIVES: The authors used transthoracic 3-dimensional transthoracic echocardiography (3DE) to characterize tricuspid annulus (TA) geometry and dynamics in healthy volunteers. BACKGROUND: Accurate sizing of the TA is essential for planning tricuspid annuloplasty and for implantation of new percutaneous tricuspid devices. METHODS: 3DE of the TA from 209 healthy volunteers was analyzed using custom software to measure TA area, perimeter, circularity, and dimensions at end diastole (equals tricuspid valve closure), mid-systole, end systole, and late diastole. TA intercommissural distances were measured at mid-systole. For comparison, TA diameters were measured at the same time points on multiplanar reconstruction of the 3DE datasets and on 2-dimensional transthoracic echocardiography (2DE) apical 4-chamber and right ventricular focused views. In 13 subjects with both 3DE and computed tomography, TA parameters were compared. RESULTS: 3DE TA area, perimeter, and dimensions were largest in late diastole and smallest at mid-systole/end systole. Normal tricuspid valve parameters in end diastole were 8.6 ± 2.0 cm2 for area; 10.5 ± 1.2 cm for perimeter; 36 ± 4 mm and 30 ± 4 mm for longest and shortest dimensions, respectively; and 0.83 ± 0.10 for circularity. There were no age-related changes in TA parameters. Women had larger indexed TA perimeter and longer long-axis dimensions compared with men. The longest 3DE TA dimension was significantly longer than diameters measured from both 2DE and 3D multiplanar reconstruction. 3DE TA area, perimeter, and dimensions correlated with both right atrial and right ventricular volumes, suggesting that both chambers may be determinants of TA size. TA fractional area change was 35 ± 10%. Fractional changes in both perimeter and dimensions were ≥20%. When compared with computed tomography, 3DE systematically underestimated TA parameters. CONCLUSIONS: Gender and body size should be taken into account to identify the reference values of TA dimensions. 2DE underestimates TA dimensions.

3D printing of normal and pathologic tricuspid valves from transthoracic 3D echocardiography data sets.

AIMS: To explore the feasibility of using transthoracic 3D echocardiography (3DTTE) data to generate 3D patient-specific models of tricuspid valve (TV). METHODS AND RESULTS: Multi-beat 3D data sets of the TV (32 vol/s) were acquired in five subjects with various TV morphologies from the apical approach and analysed offline with custom-made software. Coordinates representing the annulus and the leaflets were imported into MeshLab (Visual Computing Lab ISTICNR) to develop solid models to be converted to stereolithographic file format and 3D print. Measurements of the TV annulus antero-posterior (AP) and medio-lateral (ML) diameters, perimeter (P), and TV tenting height (H) and volume (V) obtained from the 3D echo data set were compared with those performed on the 3D models using a caliper, a syringe and a millimeter tape. Antero-posterior (4.2 ± 0.2 cm vs. 4.2 ± 0 cm), ML (3.7 ± 0.2 cm vs. 3.6 ± 0.1 cm), P (12.6 ± 0.2 cm vs. 12.7 ± 0.1 cm), H (11.2 ± 2.1 mm vs. 10.8 ± 2.1 mm) and V (3.0 ± 0.6 ml vs. 2.8 ± 1.4 ml) were similar (P = NS for all) when measured on the 3D data set and the printed model. The two sets of measurements were highly correlated (r = 0.991). The mean absolute error (2D - 3D) for AP, ML, P and tenting H was 0.7 ± 0.3 mm, indicating accuracy of the 3D model of <1 mm. CONCLUSION: Three-dimensional printing of the TV from 3DTTE data is feasible with highly conserved fidelity. This technique has the potential for rapid integration into clinical practice to assist with decision-making, surgical planning, and teaching.

Volumetric quantification of global and regional left ventricular function from real-time three-dimensional echocardiographic images.

BACKGROUND: Real-time 3D echocardiographic (RT3DE) data sets contain dynamic volumetric information on cardiac function. However, quantification of left ventricular (LV) function from 3D echocardiographic data is performed on cut-planes extracted from the 3D data sets and thus does not fully exploit the volumetric information. Accordingly, we developed a volumetric analysis technique aimed at quantification of global and regional LV function. METHODS AND RESULTS: RT3DE images obtained in 30 patients (Philips 7500) were analyzed by use of custom software based on the level-set approach for semiautomated detection of LV endocardial surface throughout the cardiac cycle, from which global and regional LV volume (LVV)-time and wall motion (WM)-time curves were obtained. The study design included 3 protocols. In protocol 1, time curves obtained in 16 patients were compared point-by-point with MRI data (linear regression and Bland-Altman analyses). Global LVV correlated highly with MRI (r=0.98; y=0.99x+2.3) with minimal bias (1.4 mL) and narrow limits of agreement (+/-20 mL). WM correlated highly only in basal and midventricular segments (r=0.88; y=0.85x+0.7). In protocol 2, we tested the ability of this technique to differentiate populations with known differences in LV function by studying 9 patients with dilated cardiomyopathy and 9 normal subjects. All calculated indices of global and regional systolic and diastolic LV function were significantly different between the groups. In protocol 3, we tested the feasibility of automated detection of regional WM abnormalities in 11 patients. In each segment, abnormality was detected when regional shortening fraction was below a threshold obtained in normal subjects. The automated detection agreed with expert interpretation of 2D WM in 86% of segments. CONCLUSIONS: Volumetric analysis of RT3DE data is clinically feasible and allows fast, semiautomated, dynamic measurement of LVV and automated detection of regional WM abnormalities.

A Mechanistic Explanation of the Peculiar Amphiphobic Properties of Hybrid Organic-Inorganic Coatings by Combining XPS Characterization and DFT Modeling.

We report a combined X-ray photoelectron spectroscopy and theoretical modeling analysis of hybrid functional coatings constituted by fluorinated alkylsilane monolayers covalently grafted on a nanostructured ceramic oxide (Al2O3) thin film deposited on aluminum alloy substrates. Such engineered surfaces, bearing hybrid coatings obtained via a classic sol-gel route, have been previously shown to possess amphiphobic behavior (superhydrophobicity plus oleophobicity) and excellent durability, even under simulated severe working environments. Starting from XPS, SEM, and contact angle results and analysis, and combining it with DFT results, the present investigation offers a first mechanistic explanation at a molecular level of the peculiar properties of the hybrid organic-inorganic coating in terms of composition and surface structural arrangements. Theoretical modeling shows that the active fluorinated moiety is strongly anchored on the alumina sites with single Si-O-Al bridges and that the residual valence of Si is saturated by Si-O-Si bonds which form a reticulation with two vicinal fluoroalkylsilanes. The resulting hybrid coating consists of stable rows of fluorinated alkyl chains in reciprocal contact, which form well-ordered and packed monolayers.

Mitral valve dynamics in severe aortic stenosis before and after aortic valve replacement.

BACKGROUND: The aortic and mitral valves are anatomically linked through a fibrous continuity. The investigators hypothesized that severe aortic stenosis (AS) would alter this fibrous continuity, affecting both the mitral valve and left ventricular function, and that mitral valve function would be altered after aortic valve replacement (AVR). The aim of this study was to evaluate the impact of AS and its treatment with surgical AVR on the mitral valve. METHODS: Three-dimensional transesophageal echocardiography (using a Philips iE33 system) was performed on 49 patients: 20 controls with normal valves and left ventricular function, 20 with AS and normal left ventricular function studied before and after AVR, and nine with systolic heart failure and normal valves. Custom software tracked the aortic and mitral valves in three-dimensional space, allowing automated measurements of aortic and mitral annular (MA) morphology throughout the cardiac cycle. RESULTS: Patients with AS before AVR had reduced MA velocities. After AVR, aortic and MA areas were significantly smaller throughout the cardiac cycle compared with controls and pre-AVR values. MA displacement was reduced after AVR and in patients with systolic heart failure compared with those with AS and controls. CONCLUSIONS: Dynamic MA function is changed with AS and after AVR through alterations in the aortic-mitral fibrous continuity. The prosthetic valve ring results in reduced aortic and MA areas, which could affect blood flow in and out of the left ventricle. These changes suggest that the design of future prosthetic aortic valves should be more flexible to preserve the function of the aortic-mitral fibrous continuity.

A three-dimensional echocardiographic study on aortic-mitral coupling in transcatheter aortic valve replacement.

AIMS: Normal aortic valve (AV) and mitral valve (MV) function in a reciprocal interdependent fashion. We hypothesized that MV function would be affected by severe aortic stenosis (AS) and that it would remain altered after transcatheter AV replacement (TAVR). Using three-dimensional (3D) echocardiography, we studied aortic-mitral coupling in patients with severe AS undergoing TAVR and compared them with controls. METHODS AND RESULTS: Three-dimensional transoesophageal echocardiography (Philips iE33) was performed on 43 patients: 27 with severe AS studied pre- and post-TAVR and 16 controls. A custom software tracked the aortic annulus (AoA) and mitral annulus (MA), allowing dynamic automated measurements of AoA and MA morphology, angle, and motion. The AS pre-TAVR patients had significantly reduced MA displacement, MA area, and maximum AoA area compared with the controls. Post-TAVR, MA displacement, MA area, and AoA area remained reduced. End-systolic AoA-MA angle was significantly wider in the AS patients compared with the controls and remained wider post-TAVR. Pre-TAVR, there was no difference in MA or AoA dynamics between patients with mild vs. moderate-to-severe MA calcium; Edwards-Sapien vs. a Medtronic CoreValve valve; normal vs. reduced left ventricular systolic function whereas post-TAVR, MA dynamics were significantly reduced in those with moderate-to-severe MA calcium. CONCLUSION: This is the first study to demonstrate that AS can affect a secondary 'unaffected' valve, the MV, due to the calcification in the aortic-mitral fibrous continuity. TAVR does not result in recovery of MV structure. These changes have implications in the future TAVR valve development and the possible need for MV assessment pre- and post-TAVR.

Effect of mitral valve repair on mitral-aortic coupling: a real-time three-dimensional transesophageal echocardiography study.

BACKGROUND: The aortic valve and the mitral valve (MV) are coupled via fibrous tissue. Simultaneous dynamic analysis of the two valves' annuli has demonstrated that they have synchronous and reciprocal behavior. Accordingly, the aims of this study were to characterize mitral-aortic coupling (MAC) in three-dimensional space before and after MV repair and to identify the untoward effects of annuloplasty rings on MAC compared with normal valvular function. METHODS: Real-time three-dimensional transesophageal echocardiography was performed on 28 consecutive patients with degenerative MV disease and severe mitral regurgitation before and after MV repair and in 25 age-matched control subjects. Custom software was used to semiautomatically identify the mitral and aortic annuli throughout the cardiac cycle and to measure parameters describing valvular dynamics. RESULTS: Patients with mitral regurgitation before MV repair were characterized by altered morphology and function of the MV but preserved MAC because of the maintained ability of the mitral annulus to change size and position. MV repair together with annuloplasty ring implantation forced the mitral annulus to be smaller and less pulsatile, with decreased displacement ability compared with normal mitral annuli. Because of this alteration in MAC, the "unaffected" aortic annulus became less pulsatile and less mobile. CONCLUSIONS: This study shows unwanted and unexpected changes in aortic annular function secondary to mitral valve repair with an annuloplasty ring due to altered MAC mechanisms. These changes may alter the dynamic mechanism of the aortic root that facilitates blood ejection, so MAC should be considered and evaluated from diagnosis to treatment in MV disease.

Use of a web-based application of the American College of Cardiology Foundation/American Society of Echocardiography Appropriateness Use Criteria for Transthoracic Echocardiography: a pilot study.

BACKGROUND: Clinical application of the American College of Cardiology Foundation Appropriate Use Criteria (AUC) represents a potentially feasible alternative to third-party pre-certification for imaging procedures and will soon be required as part of the accreditation process for imaging laboratories. Electronic tools that rapidly apply the AUC are needed in clinical practice. We developed and tested a web-based application of the AUC to track appropriateness of transthoracic echocardiography (TTE). METHODS: Indications for outpatient TTE studies performed in a university hospital echocardiography laboratory were assessed prospectively at the point of service using a prototype web-based AUC application (Echo AUC App). The Echo AUC App was developed on the basis of our own prior published data regarding indication frequency to minimize time and screens required for completion. Echo AUC App-determined indications were compared with blinded investigator-determined indications based on review of relevant medical records. Echo AUC App characteristics, including Echo AUC App entry time, were recorded. RESULTS: Of the 258 studies enrolled, Echo AUC App-determined TTE indications were Appropriate (A) in 77% (n = 198), Inappropriate (I) in 9% (n = 23), and Not Classified (NC) by the AUC in 14% (n = 37). Agreement between Echo AUC App- and investigator-determined classifications was excellent (94%, kappa statistic 0.83). Mean Echo AUC App study entry time was 55 seconds (range 25-280 seconds). CONCLUSION: The use of an electronic application allows rapid and accurate implementation of the AUC for TTE at the point of service. Such an application could be installed in echocardiography laboratories to track appropriateness in accordance with soon-to-be-implemented accreditation requirements. Further study of this Echo AUC App at the point of order may provide an alternative to third-party pre-certification procedures.