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Your search keyword '"Votta, Emiliano"' showing total 137 results
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137 results on '"Votta, Emiliano"'

32. Fast Approximate Quantification of Endovascular Stent Graft Displacement Forces in the Bovine Aortic Arch Variant.

Author

Sturla, Francesco, Caimi, Alessandro, Romarowski, Rodrigo M., Nano, Giovanni, Glauber, Mattia, Redaelli, Alberto, Votta, Emiliano, and Marrocco-Trischitta, Massimiliano M.

Abstract

Purpose: Displacement forces ( DF s) identify hostile landing zones for stent graft deployment in thoracic endovascular aortic repair (TEVAR). However, their use in TEVAR planning is hampered by the need for time-expensive computational fluid dynamics (CFD). We propose a novel fast-approximate computation of DF s merely exploiting aortic arch anatomy, as derived from the computed tomography (CT) and a measure of central aortic pressure. Materials and Methods: We tested the fast-approximate approach against CFD gold-standard in 34 subjects with the "bovine" aortic arch variant. For each dataset, a 3-dimensional (3D) model of the aortic arch lumen was reconstructed from computed tomography angiography and CFD then employed to compute DF s within the aortic proximal landing zones. To quantify fast-approximate DF s, the wall shear stress contribution to the DF was neglected and blood pressure space-distribution was averaged on the entire aortic wall to reliably approximate the patient-specific central blood pressure. Also, DF values were normalized on the corresponding proximal landing zone area to obtain the equivalent surface traction ( EST ). Results: Fast-approximate approach consistently reflected (r2=0.99, p<0.0001) the DF pattern obtained by CFD, with a −1.1% and 0.7° bias in DF s magnitude and orientation, respectively. The normalized EST progressively increased (p<0.0001) from zone 0 to zone 3 regardless of the type of arch, with proximal landing zone 3 showing significantly greater forces than zone 2 (p<0.0001). Upon DF normalization to the corresponding aortic surface, fast-approximate EST was decoupled in blood pressure and a dimensionless shape vector (S) reflecting aortic arch morphology. S showed a zone-specific pattern of orientation and proved a valid biomechanical blueprint of DF impact on the thoracic aortic wall. Conclusion: Requiring only a few seconds and quantifying clinically relevant biomechanical parameters of proximal landing zones for arch TEVAR, our method suits the real preoperative decision-making process. It paves the way toward analyzing large population of patients and hence to define threshold values for a future patient-specific preoperative TEVAR planning. [ABSTRACT FROM AUTHOR]

Published
2023
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35. Lung anatomy, energy load, and ventilator-induced lung injury

Author

Protti, Alessandro, Andreis, Davide T., Milesi, Marta, Iapichino, Giacomo E., Monti, Massimo, Comini, Beatrice, Pugni, Paola, Melis, Valentina, Santini, Alessandro, Dondossola, Daniele, Gatti, Stefano, Lombardi, Luciano, Votta, Emiliano, Carlesso, Eleonora, and Gattinoni, Luciano

Published
2015
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48. Mitral valve finite element modeling: implications of tissues' nonlinear response and annular motion

Author

Stevanella, Marco, Votta, Emiliano, and Redaelli, Alberto

Subjects
Finite element method -- Models, Mitral valve -- Physiological aspects, Mitral valve -- Properties, Tissues -- Physiological aspects, Engineering and manufacturing industries, Science and technology
Abstract

Finite element modeling represents an established method for the comprehension of the mitral function and for the simulation of interesting clinical scenarios. However, current models still do not include all the key aspects of the real system. We implemented a new structural finite element model that considers (i) an accurate morphological description of the valve, (ii) a description of the tissues' mechanical properties that accounts for anisotropy and nonlinearity, and (iii) dynamic boundary conditions that mimic annulus and papillary, muscles' contraction. The influence of such contraction on valve biomechanics was assessed by comparing the computed results with the ones obtained through an auxiliary model with fixed annulus and papillary muscles. At the systolic peak, the leaflets' maximum principal stress contour showed peak values in the anterior leaflet at the strut chordae insertion zone (300 kPa) and near the annulus (200-250 kPa), while much lower values were detected in the posterior leaflet. Both leaflets underwent larger tensile strains in the longitudinal direction, while in the circumferential one the anterior leaflet experienced nominal tensile strains up to 18% and the posterior one experienced compressive strains up to 23% associated with the folding of commissures and paracommissures, consistently with tissue redundancy. The force exerted by papillary muscles at the systolic peak was equal to 4.11 N, mainly borne by marginal chordae (76% of the force). Local reaction forces up to 45 mN were calculated on the annulus, leading to tensions of 89 N/m and 54 N/m for its anterior and posterior tracts, respectively. The comparison with the results of the auxiliary model showed that annular contraction mainly affects the leaflets' circumferential strains. When it was suppressed, no more compressive strains could be observed and peak strain values were located in the belly of the anterior leaflet. Computational results agree to a great extent with experimental data from literature. They provided insight into some of the features characterizing normal mitral function, such as annular contraction and leaflets' tissue anisotropy and nonlinearity. Some of the computed results may be useful in the design of surgical devices and techniques. In particular, forces applied on the annulus by the surrounding tissues could be considered as an indication for annular prostheses design. [DOI: 10.1115/1.4000107] Keywords: mitral valve, finite element modeling

Published
2009

49. Comparison of Four‐Dimensional Magnetic Resonance Imaging Analysis of Left Ventricular Fluid Dynamics and Energetics in Ischemic and Restrictive Cardiomyopathies.

Author

Riva, Alessandra, Sturla, Francesco, Pica, Silvia, Camporeale, Antonia, Tondi, Lara, Saitta, Simone, Caimi, Alessandro, Giese, Daniel, Palladini, Giovanni, Milani, Paolo, Castelvecchio, Serenella, Menicanti, Lorenzo, Redaelli, Alberto, Lombardi, Massimo, and Votta, Emiliano

Subjects
FLUID dynamics, MAGNETIC resonance imaging, IMAGE analysis, CARDIOMYOPATHIES, POTENTIAL flow
Abstract

Background: Time‐resolved three‐directional velocity‐encoded (4D flow) magnetic resonance imaging (MRI) enables the quantification of left ventricular (LV) intracavitary fluid dynamics and energetics, providing mechanistic insight into LV dysfunctions. Before becoming a support to diagnosis and patient stratification, this analysis should prove capable of discriminating between clearly different LV derangements. Purpose: To investigate the potential of 4D flow in identifying fluid dynamic and energetics derangements in ischemic and restrictive LV cardiomyopathies. Study Type: Prospective observational study. Population: Ten patients with post‐ischemic cardiomyopathy (ICM), 10 patients with cardiac light‐chain cardiac amyloidosis (AL‐CA), and 10 healthy controls were included. Field Strength/Sequence: 1.5 T/balanced steady‐state free precession cine and 4D flow sequences. Assessment: Flow was divided into four components: direct flow (DF), retained inflow, delayed ejection flow, and residual volume (RV). Demographics, LV morphology, flow components, global and regional energetics (volume‐normalized kinetic energy [KEV] and viscous energy loss [ELV]), and pressure‐derived hemodynamic force (HDF) were compared between the three groups. Statistical Tests: Intergroup differences in flow components were tested by one‐way analysis of variance (ANOVA); differences in energetic variables and peak HDF were tested by two‐way ANOVA. A P‐value of <0.05 was considered significant. Results: ICM patients exhibited the following statistically significant alterations vs. controls: reduced KEV, mostly in the basal region, in systole (−44%) and in diastole (−37%); altered flow components, with reduced DF (−33%) and increased RV (+26%); and reduced basal–apical HDF component on average by 63% at peak systole. AL‐CA patients exhibited the following alterations vs. controls: significantly reduced KEV at the E‐wave peak in the basal segment (−34%); albeit nonstatistically significant, increased peaks and altered time‐course of the HDF basal–apical component in diastole and slightly reduced HDF components in systole. Data Conclusion: The analysis of multiple 4D flow‐derived parameters highlighted fluid dynamic alterations associated with systolic and diastolic dysfunctions in ICM and AL‐CA patients, respectively. Level of Evidence: 2 Technical Efficacy Stage: 3 [ABSTRACT FROM AUTHOR]

Published
2022
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