Update on supra-annular sizing of transcatheter aortic valve prostheses in raphe-type bicuspid aortic valve disease according to the LIRA method.

Recent evidence has shown that transcatheter heart valve (THV) anchoring in bicuspid aortic valve (BAV) patients occurs at the level of the raphe, known as the LIRA (Level of Implantation at the RAphe) plane. Our previous work in a cohort of 20 patients has shown that the delineation of the perimeter and device sizing at this level is associated with optimal procedural outcome. The goals of this study were to confirm the feasibility of this method, evaluate 30-day outcomes of LIRA sizing in a larger cohort of patients, assess interobserver variation and reproducibility of this sizing methodology, and analyse the interaction of LIRA-sized prostheses with the surrounding anatomy. The LIRA sizing method was applied to consecutive patients presenting to our centre with raphe-type BAV disease between November 2018 and October 2021. Supra-annular self-expanding THVs were sized based on baseline CT scan perimeters at the LIRA plane and the virtual basal ring. In cases where there was discrepancy between the two measurements, the plane with the smallest perimeter was considered the reference for prosthesis sizing. Post-procedural device success, defined according to Valve Academic Research Consortium-2 (VARC-2) criteria, was evaluated in the overall cohort. A total of 50 patients (mean age 80 ± 6 years, 70% male) with raphe-type BAV disease underwent transcatheter aortic valve replacement (TAVR) using different THV prostheses. The LIRA plane method appeared to be highly successful (100% VARC-2 device success) with no procedural mortality, no valve migration, no moderate-severe paravalvular leak, and low transprosthetic gradients (residual mean gradient 8.2 ± 3.4 mmHg). There were no strokes, no in-hospital or 30-day mortality, and an incidence of in-hospital pacemaker implantation of 10%. Furthermore, measurement of the LIRA plane perimeter was highly reproducible between observers (r = 0.980; P < 0.001) and predictive of the post-procedural prosthetic valve perimeter on CT scanning (r = 0.981; P < 0.001). We confirm the feasibility of supra-annular sizing using the LIRA method in a large cohort of patients with high procedural success and good clinical outcomes at 30 days. Application of the LIRA method optimizes THV prosthesis sizing in patients with raphe-type BAV disease.

Self-expanding transcatheter aortic valve infolding: Current evidence, diagnosis, and management.

BACKGROUND: Prosthetic valve infolding is a rare but severe complication of transcatheter aortic valve implantation (TAVI) with self-expanding valves. However, currently available clinical data are limited and fragmented. OBJECTIVES: This report aims to provide a comprehensive overview of this complication focusing on predisposing factors, clinical presentation, diagnostic findings, treatment and clinical outcomes. METHODS: A systematic review of the literature was performed to identify cases of infolding occurring during TAVI with self-expanding valves published until August 2020. These data were pooled with all the retrospectively identified infolding cases occurred at San Raffaele Scientific Institute between December 2014 and August 2020. RESULTS: A total of 34 cases were included. Among patients with available data, 38% received a first-generation CoreValve, and 62% a second-generation Evolut R (82%) or Evolut PRO (18%). Infolding occurred mostly with ≥29-mm valves (94%). Predisposing factors included resheathing of a second-generation valve (82%), heavy calcification of the native valve (65%), lack of predilatation (16%), Sievers type-1 bicuspid aortic valve (11%), and improper valve loading (5%). Infolding resulted in severe PVL causing hemodynamic instability (29%) or cardiac arrest (12%). Postdilatation was the treatment strategy in 68%, while prosthesis replacement with a new device in 23% of cases. Device success rate was 82%. Death and stroke occurred in 3% and 12% of cases. CONCLUSIONS: Prosthetic valve infolding is typically observed after resheathing of a large-size self-expanding TAVI. When infolding is timely diagnosed, prosthesis removal and replacement should be pursued. Further studies are required to precisely define predisposing factors to prevent this complication.

Continuous-time stochastic processes for the spread of COVID-19 disease simulated via a Monte Carlo approach and comparison with deterministic models.

Two stochastic models are proposed to describe the evolution of the COVID-19 pandemic. In the first model the population is partitioned into four compartments: susceptible S, infected I, removed R and dead people D. In order to have a cross validation, a deterministic version of such a model is also devised which is represented by a system of ordinary differential equations with delays. In the second stochastic model two further compartments are added: the class A of asymptomatic individuals and the class L of isolated infected people. Effects such as social distancing measures are easily included and the consequences are analyzed. Numerical solutions are obtained with Monte Carlo simulations. Quantitative predictions are provided which can be useful for the evaluation of political measures, e.g. the obtained results suggest that strategies based on herd immunity are too risky. Finally, the models are calibrated on data referring to the second wave of infection in Italy.

First-in-man Valve-in-Valve with the new balloon-expandable Myval transcatheter heart valve in a failed sutureless Perceval bioprosthesis.

Sutureless aortic bioprostheses were introduced more than ten years ago, with the aim of decreasing cross-clamp time and thus becoming the first choice in older patients for many surgeons. However, published data are limited to a 5-year follow-up, and some cases of deterioration have already been described. High-risk patients who once have benefitted from a fast sutureless aortic replacement and now are experiencing a prosthesis dysfunction, could take advantage of a percutaneous Valve-in-Sutureless technique. Furthermore, thanks to technological improvement, new transcatheter prostheses have been designed, allowing a more precise positioning. In this report, we described the first Myval-in-Perceval case, which resulted in a safe and effective procedure.

Correction: Camiola, V.D., et al. Equilibrium Wigner Function for Fermions and Bosons in the Case of a General Energy Dispersion Relation. Entropy 2020, 22, 1023.

In Section 5 of Equilibrium Wigner Function for Fermions and Bosons in the Case of a General Energy Dispersion Relation [...].

About the Definition of the Local Equilibrium Lattice Temperature in Suspended Monolayer Graphene.

The definition of temperature in non-equilibrium situations is among the most controversial questions in thermodynamics and statistical physics. In this paper, by considering two numerical experiments simulating charge and phonon transport in graphene, two different definitions of local lattice temperature are investigated: one based on the properties of the phonon-phonon collision operator, and the other based on energy Lagrange multipliers. The results indicate that the first one can be interpreted as a measure of how fast the system is trying to approach the local equilibrium, while the second one as the local equilibrium lattice temperature. We also provide the explicit expression of the macroscopic entropy density for the system of phonons, by which we theoretically explain the approach of the system toward equilibrium and characterize the nature of the equilibria, in the spatially homogeneous case.

Self-expandable valve-in-valve treatment for failing sutureless aortic bioprosthesis.

Aortic valve replacement still represents the gold standard treatment for severe symptomatic aortic stenosis. Sutureless bioprostheses have been so far developed to enhance the minimally invasive approach, resulting in a reduction of cross-clamp time. Even if the first implantation was carried out more than 10 years ago, some cases of valve degeneration treated with balloon-expandable valve-in-valve procedures have been previously described in the literature. Here, we present a case of early sutureless valve degeneration resulting in severe aortic regurgitation. After careful evaluation of the patient's comorbidities, a successful valve-in-valve was finally performed using a self-expandable transcatheter prosthesis. A wide discussion of the Heart Team decision-making process and of the technical aspects has been addressed.

Equilibrium Wigner Function for Fermions and Bosons in the Case of a General Energy Dispersion Relation.

The approach based on the Wigner function is considered as a viable model of quantum transport which allows, in analogy with the semiclassical Boltzmann equation, to restore a description in the phase-space. A crucial point is the determination of the Wigner function at the equilibrium which stems from the equilibrium density function. The latter is obtained by a constrained maximization of the entropy whose formulation in a quantum context is a controversial issue. The standard expression due to Von Neumann, although it looks a natural generalization of the classical Boltzmann one, presents two important drawbacks: it is conserved under unitary evolution time operators, and therefore cannot take into account irreversibility; it does not include neither the Bose nor the Fermi statistics. Recently a diagonal form of the quantum entropy, which incorporates also the correct statistics, has been proposed in Snoke et al. (2012) and Polkovnikov (2011). Here, by adopting such a form of entropy, with an approach based on the Bloch equation, the general condition that must be satisfied by the equilibrium Wigner function is obtained for general energy dispersion relations, both for fermions and bosons. Exact solutions are found in particular cases. They represent a modulation of the solution in the non degenerate situation.

Anatomic and procedural associations of transcatheter heart valve displacement following Evolut R implantation.

OBJECTIVES: This study aimed to predict the displacement of self-expanding transcatheter heart valves (THV) during final deployment. BACKGROUND: Accurate device positioning during transcatheter aortic valve implantation (TAVI) is crucial for optimal results. METHODS: At our institution, 103 patients who underwent transfemoral TAVI with Evolut R were retrospectively identified. Multiple linear regression models were created, and a predictor equation was built to quantify the factors that may affect THV behavior. RESULTS: Multiple linear regression analysis for THV displacement on the left coronary cusp (LCC) identified the angle between the THV and the ascending aorta (ATA), predilation, and less operator experience as independent predictors of upward displacement, whereas estimated glomerular filtration rate (eGFR) was inversely related with THV behavior (95% confidence interval: 0.219 to 0.340, 0.447 to 2.092, 0.165 to 1.757, and -0.053 to -0.011, respectively). Predictors of THV displacement on the noncoronary cusp side could not be identified using this model. CONCLUSIONS: The ATA at the point of recapture, predilation, and less operator experience were independent predictors of upward displacement of THV on the LCC side. eGFR was an independent predictor of THV downward displacement on the LCC side. Of them, the ATA was the strongest predictor. Physicians may need to adjust this angle adequately before deployment to achieve the appropriate position.

A comparison of the fully repositionable and retrievable Boston Lotus and direct flow medical valves for the treatment of severe aortic stenosis: A single center experience.

BACKGROUND: Second generation transcatheter aortic valve implantation (TAVI) devices have been designed to reduce the rate of paravalvular leak (PVL) and other complications. An important technological advancement has been the ability to fully reposition devices to facilitate optimal implantation depth and position to reduce the likelihood of PVL. OBJECTIVES: To compare procedural and 30-day outcomes according to the Valve Academic Research Consortium (VARC)-2 criteria following TAVI with the fully repositionable and retrievable Lotus and DFM devices. METHODS AND RESULTS: 175 patients with severe aortic stenosis underwent transfemoral TAVI with the Lotus (n = 60) and DFM (n = 115) valve. Baseline clinical characteristics did not differ between the two groups. All devices were successfully implanted, with one case of valve embolization in the Lotus group. Device success (95 vs. 98.2%, P = 0.89), VARC-defined combined safety (90 vs. 93%, P = 0.48), and clinical efficacy (86.7 vs. 90.4%, P = 0.65) rates at 30-days were similar between Lotus and DFM groups. There was no severe PVL; one patient in both Lotus and DFM group developed moderate PVL after the procedure. The Lotus valve was associated with a higher rate of new pacemaker implantation (37.3 vs. 11.2%, P < 0.001) and a lower mean aortic gradient (9.4 ± 5 vs. 12.3 ± 5, P < 0.001) at 30-days as compared with the DFM valve. CONCLUSIONS: In this single-center, retrospective analysis, both Lotus and DFM devices demonstrated excellent device success, safety and efficacy at 30-day follow-up. The DFM valve was associated with minimally higher transvalvular gradients but lower new pacemaker implantation rates when compared to the Lotus valve.

Valve-in-valve transcatheter aortic valve implantation: The issues behind crossing a bioprosthesis.

Valve-in-valve transcatheter aortic valve implantation (ViV TAVI) is rapidly arising as a safe and effective alternative to redo-surgery in the treatment of bioprostheses deterioration. While scientific community is currently focusing its attention on the most common limitations related to this procedure, such as the risk of coronary obstruction and patient-prosthesis mismatch, data regarding the first step of a ViV TAVI, the crossing of a degenerated bioprosthesis, are still lacking. The aim of this review is to analyze the available information about bioprosthesis crossing, to show the inherent challenges encountered by interventional cardiologists during valve crossing and to describe the current strategies to perform a correct crossing.

Special Issue: Thermo-Electric and Mechanical Properties of Carbon-Based Polymer.

Although on the one hand polymers are arousing increasing interest due to their remarkable properties in terms of lightness, cost-effectiveness, easy processing, and mechanical resistance, on the other hand, they still present several restrictions in practical applications [...].

Experimental, Theoretical and Numerical Studies on Thermal Properties of Lightweight 3D Printed Graphene-Based Discs with Designed Ad Hoc Air Cavities.

The current state of the art on material science emphasizes recent research efforts aimed at designing novel materials characterized by low-density and advanced properties. The present article reports the experimental, theoretical and simulation results on the thermal behavior of 3D printed discs. Filaments of pure poly (lactic acid) PLA and filled with 6 wt% of graphene nanoplatelets (GNPs) are used as feedstocks. Experiments indicate that the introduction of graphene enhances the thermal properties of the resulting materials since the conductivity passes from the value of 0.167 [W/mK] for unfilled PLA to 0.335 [W/mK] for reinforced PLA, which corresponds to a significantly improvement of 101%. Exploiting the potential of 3D printing, different air cavities have been intentionally designed to develop new lightweight and more cost-effective materials without compromising their thermal performances. Furthermore, some cavities are equal in volume but different in the geometry; it is necessary to investigate how this last characteristic and its possible orientations affect the overall thermal behavior compared to that of an air-free specimen. The influence of air volume is also investigated. Experimental results are supported by theoretical analysis and simulation studies based on the finite element method. The results aim to be a valuable reference resource in the field of design and optimization of lightweight advanced materials.

A European Society of Oncologic Imaging (ESOI) survey on the radiological assessment of response to oncologic treatments in clinical practice.

OBJECTIVES: To present the results of a survey on the assessment of treatment response with imaging in oncologic patient, in routine clinical practice. The survey was promoted by the European Society of Oncologic Imaging to gather information for the development of reporting models and recommendations. METHODS: The survey was launched on the European Society of Oncologic Imaging website and was available for 3 weeks. It consisted of 5 sections, including 24 questions related to the following topics: demographic and professional information, methods for lesion measurement, how to deal with diminutive lesions, how to report baseline and follow-up examinations, which previous studies should be used for comparison, and role of RECIST 1.1 criteria in the daily clinical practice. RESULTS: A total of 286 responses were received. Most responders followed the RECIST 1.1 recommendations for the measurement of target lesions and lymph nodes and for the assessment of tumor response. To assess response, 48.6% used previous and/or best response study in addition to baseline, 25.2% included the evaluation of all main time points, and 35% used as the reference only the previous study. A considerable number of responders used RECIST 1.1 criteria in daily clinical practice (41.6%) or thought that they should be always applied (60.8%). CONCLUSION: Since standardized criteria are mainly a prerogative of clinical trials, in daily routine, reporting strategies are left to radiologists and oncologists, which may issue local and diversified recommendations. The survey emphasizes the need for more generally applicable rules for response assessment in clinical practice. CRITICAL RELEVANCE STATEMENT: Compared to clinical trials which use specific criteria to evaluate response to oncological treatments, the free narrative report usually adopted in daily clinical practice may lack clarity and useful information, and therefore, more structured approaches are needed. KEY POINTS: · Most radiologists consider standardized reporting strategies essential for an objective assessment of tumor response in clinical practice. · Radiologists increasingly rely on RECIST 1.1 in their daily clinical practice. · Treatment response evaluation should require a complete analysis of all imaging time points and not only of the last.

Experimental and Simulation Studies of Temperature Effect on Thermophysical Properties of Graphene-Based Polylactic Acid.

Overheating effect is a crucial issue in different fields. Thermally conductive polymer-based heat sinks, with lightweight and moldability features as well as high-performance and reliability, are promising candidates in solving such inconvenience. The present work deals with the experimental evaluation of the temperature effect on the thermophysical properties of nanocomposites made with polylactic acid (PLA) reinforced with two different weight percentages (3 and 6 wt%) of graphene nanoplatelets (GNPs). Thermal conductivity and diffusivity, as well as specific heat capacity, are measured in the temperature range between 298.15 and 373.15 K. At the lowest temperature (298.15 K), an improvement of 171% is observed for the thermal conductivity compared to the unfilled matrix due to the addition of 6 wt% of GNPs, whereas at the highest temperature (372.15 K) such enhancement is about of 155%. Some of the most important mechanical properties, mainly hardness and Young's modulus, maximum flexural stress, and tangent modulus of elasticity, are also evaluated as a function of the GNPs content. Moreover, thermal simulations based on the finite element method (FEM) have been carried out to predict the thermal performance of the investigated nanocomposites in view of their practical use in thermal applications. Results seem quite suitable in this regard.

Experimental, Theoretical and Simulation Studies on the Thermal Behavior of PLA-Based Nanocomposites Reinforced with Different Carbonaceous Fillers.

Many research efforts have been directed towards enhancing the thermal properties of polymers, since they are classically regarded as thermal insulators. To this end, the present study focuses on the thermal investigation of poly(lactic acid) (PLA) filled with two types of carbon nanotubes (trade names: TNIMH4 and N7000), two type of graphene nanoplatelets (trade names: TNIGNP and TNGNP), or their appropriate combination. A significant increase in the thermal conductivity by 254% with respect to that of unfilled polymer was achieved in the best case by using 9 wt% TNIGNP, resulting from its favorable arrangement and the lower thermal boundary resistance between the two phases, matrix and filler. To theoretically assist the design of such advanced nanocomposites, Design of Experiments (DoE) and Response Surface Method (RSM) were employed, respectively, to obtain information on the conditioning effect of each filler loading on the thermal conductivity and to find an analytical relationship between them. The numerical results were compared with the experimental data in order to confirm the reliability of the prediction. Finally, a simulation study was carried out with Comsol Multiphysics® for a comparative study between two heat sinks based on pure PLA, and to determine the best thermally performing nanocomposite with a view towards potential use in heat transfer applications.

Systematic Fluoroscopic-Echocardiographic Fusion Imaging Protocol for Transcatheter Edge-to-Edge Mitral Valve Repair Intraprocedural Monitoring.

BACKGROUND: Whether fluoroscopic-echocardiographic fusion imaging (FI) might offer added value for intraprocedural guidance during transcatheter edge-to-edge mitral valve repair is yet unknown, and few data exist regarding the safety and feasibility of this novel technology. METHODS: The aim of this single-center study was to test and validate a FI protocol for intraprocedural monitoring of transcatheter edge-to-edge mitral valve repair and assess its clinical usefulness. Eighty patients underwent MitraClip implantation using FI guidance (FI+) for either degenerative (35%) or functional (65%) mitral regurgitation and were compared with the last 80 patients before FI introduction, treated using conventional echocardiography and fluoroscopic monitoring (FI-). RESULTS: The number of patients treated for functional and degenerative mitral regurgitation was similar between the FI+ and FI- groups, as well as the number of devices implanted (1.51 ± 0.5 vs 1.58 ± 0.6, P = .46). The prevalence of complex mitral anatomy for percutaneous repair was high (32.5%, up to 39.2% in the hybrid arm). Fluoroscopy time was significantly lower in FI+ patients (37.3 ± 14.6 vs 48.3 ± 28.3 min, P = .003), but not kerma area product (91.5 ± 74.1 vs 108.8 ± 105.0 Gy · cm2, P = .23) or procedural time (92.2 ± 36.1 vs 103.1 ± 42.7 min, P = .086). After adjusting for confounding factors (MitraClip XT device and complex anatomy), FI reduced fluoroscopy time (coefficient = -10.4 min; 95% CI, -18.03 to -2.82; P = .007) and improved procedural success at the end of the procedure (odds ratio, 2.87; 95% CI, 1.00 to 8.24; P = .049) and discharge (odds ratio, 2.24; 95% CI, 1.04 to 4.80; P = .039). Rates of periprocedural complications were similar in both groups (8.9% vs 13.0%, P = .40). CONCLUSIONS: The authors describe the systematic use of an FI protocol for intraprocedural guidance during transcatheter edge-to-edge mitral valve repair, demonstrating a reduction in fluoroscopy time and an improvement in procedural success in a population with a high prevalence of challenging mitral anatomy for percutaneous repair.

[Transcatheter aortic valve implantation for aortic regurgitation in patients with left ventricular assist device]. / Impianto transcatetere di valvola aortica per insufficienza aortica nei pazienti con assistenza ventricolare sinistra.

Aortic valve regurgitation is a not negligible complication of prolonged support with continuous-flow left ventricular assist device (LVAD) and is associated with recurrence of heart failure and reduced survival. Transcatheter aortic valve implantation has been described as a feasible option in this setting, usually with self-expanding prosthesis. Giving the absence of valvular calcification, a proper prosthesis oversizing should be guaranteed in order to achieve sufficient sealing and avoid prosthesis migration or paravalvular leak. Current self-expanding prosthesis may be too small to fit aortic annulus anatomies without calcification and with the need of significant oversize. We report the first case of 32 mm balloon expandable Myval prosthesis implantation in a patient with LVAD-related aortic regurgitation. Large balloon-expandable prosthesis can be considered when a significant oversize is needed.

Surgical feasibility of ascending aorta manipulation after transcatheter aortic valve implantation: a computed tomography theoretical analysis.

AIMS: The expansion of TAVI will involve an increase in the frequency of emergent or late cardiac surgery after THV implantation. This study was designed to investigate the anatomical feasibility of surgical cross-clamp and aortotomy after TAVI through a post-TAVI CT-scan assessment. METHODS AND RESULTS: We retrospectively analysed 117 CTs acquired after TAVI procedures with high stent prostheses in three high-volume centres between October 2008 and May 2017. The mean distance observed between the innominate artery and the top of the transcatheter heart valve was 45±11 mm, being <30 mm in 8/117 (6.8%) patients and <20 mm in none. The mean distance between the sinotubular junction and the first free site for aortotomy was 22±7 mm (>20 mm in 78/117 [66.7%] cases). A total of 56/117 (47.9%) patients showed a complete continuous contact between the anterior aortic wall and the anterior part of the valve stent. CONCLUSIONS: Aortic cross-clamp appears not to be an issue when cardiac surgery is needed after TAVI; however, a careful and possibly higher aortotomy may be required. CT should be performed prior to planned cardiac surgery after TAVI to determine a safe positioning for aortic cross-clamp and aortotomy.