Interlayer engineering of Fe3GeTe2: From 3D superlattice to 2D monolayer.

The discoveries of ferromagnetism down to the atomically thin limit in van der Waals (vdW) crystals by mechanical exfoliation have enriched the family of magnetic thin films [C. Gong et al., Nature 546, 265-269 (2017) and B. Huang et al., Nature 546, 270-273 (2017)]. However, compared to the study of traditional magnetic thin films by physical deposition methods, the toolbox of the vdW crystals based on mechanical exfoliation and transfer suffers from low yield and ambient corrosion problem and now is facing new challenges to study magnetism. For example, the formation of magnetic superlattice is difficult in vdW crystals, which limits the study of the interlayer interaction in vdW crystals [M. Gibertini, M. Koperski, A. F. Morpurgo, K. S. Novoselov, Nat. Nanotechnol. 14, 408-419 (2019)]. Here, we report a strategy of interlayer engineering of the magnetic vdW crystal Fe3GeTe2 (FGT) by intercalating quaternary ammonium cations into the vdW spacing. Both three-dimensional (3D) vdW superlattice and two-dimensional (2D) vdW monolayer can be formed by using this method based on the amount of intercalant. On the one hand, the FGT superlattice shows a strong 3D critical behavior with a decreased coercivity and increased domain wall size, attributed to the co-engineering of the anisotropy, exchange interaction, and electron doping by intercalation. On the other hand, the 2D vdW few layers obtained by over-intercalation are capped with organic molecules from the bulk crystal, which not only enhances the ferromagnetic transition temperature (TC), but also substantially protects the thin samples from degradation, thus allowing the preparation of large-scale FGT ink in ambient environment.

Clinical and Hemodynamic Outcomes of Balloon-Expandable Mitral Valve-in-Valve Positioning and Asymmetric Deployment: The VIVID Registry.

BACKGROUND: Mitral valve-in-valve (ViV) is associated with suboptimal hemodynamics and rare left ventricular outflow tract (LVOT) obstruction. OBJECTIVES: This study aimed to determine whether device position and asymmetry are associated with these outcomes. METHODS: Patients undergoing SAPIEN 3 (Edwards Lifesciences) mitral ViV included in the VIVID (Valve-in-Valve International Data) Registry were studied. Clinical endpoints are reported according to Mitral Valve Academic Research Consortium definitions. Residual mitral valve stenosis was defined as mean gradient ≥5 mm Hg. Depth of implantation (percentage of transcatheter heart valve [THV] atrial to the bioprosthesis ring) and asymmetry (ratio of 2 measures of THV height) were evaluated. RESULTS: A total of 222 patients meeting the criteria for optimal core lab evaluation were studied (age 74 ± 11.6 years; 61.9% female; STS score = 8.3 ± 7.1). Mean asymmetry was 6.2% ± 4.4%. Mean depth of implantation was 19.0% ± 10.3% atrial. Residual stenosis was common (50%; mean gradient 5.0 ± 2.6 mm Hg). LVOT obstruction occurred in 7 cases (3.2%). Implantation depth was not a predictor of residual stenosis (OR: 1.19 [95% CI: 0.92-1.55]; P = 0.184), but more atrial implantation was protective against LVOT obstruction (0.7% vs 7.1%; P = 0.009; per 10% atrial, OR: 0.48 [95% CI: 0.24-0.98]; P = 0.044). Asymmetry was found to be an independent predictor of residual stenosis (per 10% increase, OR: 2.30 [95% CI: 1.10-4.82]; P = 0.027). CONCLUSIONS: Valve stenosis is common after mitral ViV. Asymmetry was associated with residual stenosis. Depth of implantation on its own was not associated with residual stenosis but was associated with LVOT obstruction. Technical considerations to reduce postdeployment THV asymmetry should be considered.

Late Bleeding Events in Patients Undergoing Percutaneous Coronary Intervention in the Workup Pre-TAVR.

BACKGROUND: In patients undergoing percutaneous coronary intervention (PCI) in the work-up pre-transcatheter aortic valve replacement (TAVR), the incidence and clinical impact of late bleeding events (LBEs) remain largely unknown. OBJECTIVES: This study sought to determine the incidence, clinical characteristics, associated factors, and outcomes of LBEs in patients undergoing PCI in the work-up pre-TAVR. METHODS: This was a multicenter study including 1,457 consecutive patients (mean age 81 ± 7 years; 41.5% women) who underwent TAVR and survived beyond 30 days. LBEs (>30 days post-TAVR) were defined according to the Valve Academic Research Consortium-2 criteria. RESULTS: LBEs occurred in 116 (7.9%) patients after a median follow-up of 23 (IQR: 12-40) months. Late bleeding was minor, major, and life-threatening or disabling in 21 (18.1%), 63 (54.3%), and 32 (27.6%) patients, respectively. Periprocedural (<30 days post-TAVR) major bleeding and the combination of antiplatelet and anticoagulation therapy at discharge were independent factors associated with LBEs (P ≤ 0.02 for all). LBEs conveyed an increased mortality risk at 4-year follow-up compared with no bleeding (43.9% vs 36.0; P = 0.034). Also, LBE was identified as an independent predictor of all-cause mortality after TAVR (HR: 1.39; 95% CI: 1.05-1.83; P = 0.020). CONCLUSIONS: In TAVR candidates with concomitant significant coronary artery disease requiring percutaneous treatment, LBEs after TAVR were frequent and associated with increased mortality. Combining antiplatelet and anticoagulation regimens and the occurrence of periprocedural bleeding determined an increased risk of LBEs. Preventive strategies should be pursued for preventing late bleeding after TAVR, and further studies are needed to provide more solid evidence on the most safe and effective antithrombotic regimen post-TAVR in this challenging group of patients.

Selective Electron-Phonon Coupling in Dimerized 1T-TaS2 Revealed by Resonance Raman Spectroscopy.

The layered transition-metal dichalcogenide material 1T-TaS2 possesses successive phase transitions upon cooling, resulting in strong electron-electron correlation effects and the formation of charge density waves (CDWs). Recently, a dimerized double-layer stacking configuration was shown to form a Peierls-like instability in the electronic structure. To date, no direct evidence for this double-layer stacking configuration using optical techniques has been reported, in particular through Raman spectroscopy. Here, we employ a multiple excitation and polarized Raman spectroscopy to resolve the behavior of phonons and electron-phonon interactions in the commensurate CDW lattice phase of dimerized 1T-TaS2. We observe a distinct behavior from what is predicted for a single layer and probe a richer number of phonon modes that are compatible with the formation of double-layer units (layer dimerization). The multiple-excitation results show a selective coupling of each Raman-active phonon with specific electronic transitions hidden in the optical spectra of 1T-TaS2, suggesting that selectivity in the electron-phonon coupling must also play a role in the CDW order of 1T-TaS2.

The Impact of Sonothrombolysis on Left Ventricular Diastolic Function and Left Atrial Mechanics Preventing Left Atrial Remodeling in Patients With ST Elevation Acute Myocardial Infarction.

BACKGROUND: The diagnostic ultrasound-guided high mechanical index impulses during an intravenous microbubble infusion (sonothrombolysis) improve myocardial perfusion in acute ST segment elevation myocardial infarction, but its effect on left ventricular diastolic dysfunction (DD), left atrial (LA) mechanics and remodeling is unknown. We assessed the effect of sonothrombolysis on DD grade and LA mechanics. METHODS: One hundred patients (59 ± 10 years; 34% women) were randomized to receive either high mechanical index impulses plus percutaneous coronary intervention (PCI) (therapy group) or PCI only (control group) (n = 50 in each group). Diastolic dysfunction grade and LA mechanics were assessed immediately before and after PCI and at 48 to 72 hours, 1 month, and 6 months of follow-up. Diastolic dysfunction grades were classified as grades I, II, and III. The LA mechanics was obtained by two-dimensional speckle-tracking echocardiography-derived global longitudinal strain (GLS). RESULTS: As follow-up time progressed, increased DD grade was observed more frequently in the control group than in the therapy group at 1 month and 6 months of follow-up (all P < .05). The LA-GLS values were incrementally higher in the therapy group when compared with the control group at 48 to 72 hours, 24.0% ± 7.3% in the therapy group versus 19.6% ± 7.2% in the control group, P = .005; at 1 month, 25.3% ± 6.3% in the therapy group versus 21.5% ± 8.3% in the control group, P = .020; and at 6 months, 26.2% ± 8.7% in the therapy group versus 21.6% ± 8.5% in the control group, P = .015. The therapy group was less likely to experience LA remodeling (odds ratio, 2.91 [1.10-7.73]; P = .03). LA-GLS was the sole predictor of LA remodeling (odds ratio, 0.79 [0.67-0.94]; P = .006). CONCLUSION: Sonothrombolysis is associated with better DD grade and LA mechanics, reducing LA remodeling.

Comprehensive myocardial characterization using cardiac magnetic resonance associates with outcomes in low gradient severe aortic stenosis.

AIMS: This study sought to compare cardiac magnetic resonance (CMR) characteristics according to different flow/gradient patterns of aortic stenosis (AS) and to evaluate their prognostic value in patients with low-gradient AS. METHODS AND RESULTS: This international prospective multicentric study included 147 patients with low-gradient moderate to severe AS who underwent comprehensive CMR evaluation of left ventricular global longitudinal strain (LVGLS), extracellular volume fraction (ECV), and late gadolinium enhancement (LGE). All patients were classified as followings: classical low-flow low-gradient (LFLG) [mean gradient (MG) < 40 mmHg and left ventricular ejection fraction (LVEF) < 50%]; paradoxical LFLG [MG < 40 mmHg, LVEF ≥ 50%, and stroke volume index (SVi) < 35 ml/m2]; and normal-flow low-gradient (MG < 40 mmHg, LVEF ≥ 50%, and SVi ≥ 35 ml/m2). Patients with classical LFLG (n = 90) had more LV adverse remodelling including higher ECV, and higher LGE and volume, and worst LVGLS. Over a median follow-up of 2 years, 43 deaths and 48 composite outcomes of death or heart failure hospitalizations occurred. Risks of adverse events increased per tertile of LVGLS: hazard ratio (HR) = 1.50 [95% CI, 1.02-2.20]; P = 0.04 for mortality; HR = 1.45 [1.01-2.09]; P < 0.05 for composite outcome; per tertile of ECV, HR = 1.63 [1.07-2.49]; P = 0.02 for mortality; HR = 1.54 [1.02-2.33]; P = 0.04 for composite outcome. LGE presence also associated with higher mortality, HR = 2.27 [1.01-5.11]; P < 0.05 and composite outcome, HR = 3.00 [1.16-7.73]; P = 0.02. The risk of mortality and the composite outcome increased in proportion to the number of impaired components (i.e. LVGLS, ECV, and LGE) with multivariate adjustment. CONCLUSIONS: In this international prospective multicentric study of low-gradient AS, comprehensive CMR assessment provides independent prognostic value that is cumulative and incremental to clinical and echocardiographic characteristics.

Optical absorption of interlayer excitons in transition-metal dichalcogenide heterostructures.

Interlayer excitons, electron-hole pairs bound across two monolayer van der Waals semiconductors, offer promising electrical tunability and localizability. Because such excitons display weak electron-hole overlap, most studies have examined only the lowest-energy excitons through photoluminescence. We directly measured the dielectric response of interlayer excitons, which we accessed using their static electric dipole moment. We thereby determined an intrinsic radiative lifetime of 0.40 nanoseconds for the lowest direct-gap interlayer exciton in a tungsten diselenide/molybdenum diselenide heterostructure. We found that differences in electric field and twist angle induced trends in exciton transition strengths and energies, which could be related to wave function overlap, moiré confinement, and atomic reconstruction. Through comparison with photoluminescence spectra, this study identifies a momentum-indirect emission mechanism. Characterization of the absorption is key for applications relying on light-matter interactions.

Mitral Valve Infective Endocarditis after Trans-Catheter Aortic Valve Implantation.

Scarce data exist on mitral valve (MV) infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI). This multicenter study included a total of 579 patients with a diagnosis of definite IE after TAVI from the IE after TAVI International Registry and aimed to evaluate the incidence, characteristics, management, and outcomes of MV-IE after TAVI. A total of 86 patients (14.9%) had MV-IE. These patients were compared with 284 patients (49.1%) with involvement of the transcatheter heart valve (THV) only. Two factors were found to be associated with MV-IE: the use of self-expanding valves (adjusted odds ratio 2.49, 95% confidence interval [CI] 1.23 to 5.07, p = 0.012), and the presence of an aortic regurgitation ≥2 at discharge (adjusted odds ratio 3.33; 95% CI 1.43 to 7.73, p <0.01). There were no differences in IE timing and causative microorganisms between groups, but surgical management was significantly lower in patients with MV-IE (6.0%, vs 21.6% in patients with THV-IE, p = 0.001). All-cause mortality rates at 2-year follow-up were high and similar between patients with MV-IE (51.4%, 95% CI 39.8 to 64.1) and patients with THV-IE (51.5%, 95% CI 45.4 to 58.0) (log-rank p = 0.295). The factors independently associated with increased mortality risk in patients with MV-IE were the occurrence of heart failure (adjusted p <0.001) and septic shock (adjusted p <0.01) during the index hospitalization. One of 6 IE episodes after TAVI is localized on the MV. The implantation of a self-expanding THV and the presence of an aortic regurgitation ≥2 at discharge were associated with MV-IE. Patients with MV-IE were rarely operated on and had a poor prognosis at 2-year follow-up.

Structure of the moiré exciton captured by imaging its electron and hole.

Interlayer excitons (ILXs) - electron-hole pairs bound across two atomically thin layered semiconductors - have emerged as attractive platforms to study exciton condensation1-4, single-photon emission and other quantum information applications5-7. Yet, despite extensive optical spectroscopic investigations8-12, critical information about their size, valley configuration and the influence of the moiré potential remains unknown. Here, in a WSe2/MoS2 heterostructure, we captured images of the time-resolved and momentum-resolved distribution of both of the particles that bind to form the ILX: the electron and the hole. We thereby obtain a direct measurement of both the ILX diameter of around 5.2 nm, comparable with the moiré-unit-cell length of 6.1 nm, and the localization of its centre of mass. Surprisingly, this large ILX is found pinned to a region of only 1.8 nm diameter within the moiré cell, smaller than the size of the exciton itself. This high degree of localization of the ILX is backed by Bethe-Salpeter equation calculations and demonstrates that the ILX can be localized within small moiré unit cells. Unlike large moiré cells, these are uniform over large regions, allowing the formation of extended arrays of localized excitations for quantum technology.

Transcatheter versus surgical aortic valve replacement in patients with morbid obesity: a multicentre propensity score-matched analysis.

BACKGROUND: Morbidly obese (MO) patients are increasingly undergoing transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR) for severe aortic stenosis (AS). However, the best therapeutic strategy for these patients remains a matter for debate. AIMS: Our aim was to compare the periprocedural and mid-term outcomes in MO patients undergoing TAVR versus SAVR. METHODS: A multicentre retrospective study including consecutive MO patients (body mass index ≥40 kg/m2, or ≥35 kg/m2 with obesity-related comorbidities) from 18 centres undergoing either TAVR (n=860) or biological SAVR (n=696) for severe AS was performed. Propensity score matching resulted in 362 pairs. RESULTS: After matching, periprocedural complications, including blood transfusion (14.1% versus 48.1%; p<0.001), stage 2-3 acute kidney injury (3.99% versus 10.1%; p=0.002), hospital-acquired pneumonia (1.7% versus 5.8%; p=0.005) and access site infection (1.5% versus 5.5%; p=0.013), were more common in the SAVR group, as was moderate to severe patient-prosthesis mismatch (PPM; 9.9% versus 39.4%; p<0.001). TAVR patients more frequently required permanent pacemaker implantation (14.4% versus 5.6%; p<0.001) and had higher rates of ≥moderate residual aortic regurgitation (3.3% versus 0%; p=0.001). SAVR was an independent predictor of moderate to severe PPM (hazard ratio [HR] 1.80, 95% confidence interval [CI]: 1.25-2.59; p=0.002), while TAVR was not. In-hospital mortality was not different between groups (3.9% for TAVR versus 6.1% for SAVR; p=0.171). Two-year outcomes (including all-cause and cardiovascular mortality, and readmissions) were similar in both groups (log-rank p>0.05 for all comparisons). Predictors of all-cause 2-year mortality differed between the groups; moderate to severe PPM was a predictor following SAVR (HR 1.78, 95% CI: 1.10-2.88; p=0.018) but not following TAVR (p=0.737). CONCLUSIONS: SAVR and TAVR offer similar mid-term outcomes in MO patients with severe AS, however, TAVR offers some advantages in terms of periprocedural morbidity.

Visible Out-of-plane Polarized Luminescence and Electronic Resonance in Black Phosphorus.

Black phosphorus (BP) is unique among layered materials because of its homonuclear lattice and strong structural anisotropy. While recent investigations on few-layer BP have extensively explored the in-plane (a, c) anisotropy, much less attention has been given to the out-of-plane direction (b). Here, the optical response from bulk BP is probed using polarization-resolved photoluminescence (PL), photoluminescence excitation (PLE), and resonant Raman scattering along the zigzag, out-of-plane, and armchair directions. An unexpected b-polarized luminescence emission is detected in the visible, far above the fundamental gap. PLE indicates that this emission is generated through b-polarized excitation at 2.3 eV. The same electronic resonance is observed in resonant Raman with the enhancement of the Ag phonon modes scattering efficiency. These experimental results are fully consistent with DFT calculations of the permittivity tensor elements and demonstrate the remarkable extent to which the anisotropy influences the optical properties and carrier dynamics in black phosphorus.

Surgical Treatment of Patients With Infective Endocarditis After Transcatheter Aortic Valve Implantation.

BACKGROUND: The optimal treatment of patients developing infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI) is uncertain. OBJECTIVES: The goal of this study was to investigate the clinical characteristics and outcomes of patients with TAVI-IE treated with cardiac surgery and antibiotics (IE-CS) compared with patients treated with antibiotics alone (IE-AB). METHODS: Crude and inverse probability of treatment weighting analyses were applied for the treatment effect of cardiac surgery vs medical therapy on 1-year all-cause mortality in patients with definite TAVI-IE. The study used data from the Infectious Endocarditis after TAVI International Registry. RESULTS: Among 584 patients, 111 patients (19%) were treated with IE-CS and 473 patients (81%) with IE-AB. Compared with IE-AB, IE-CS was not associated with a lower in-hospital mortality (HRunadj: 0.85; 95% CI: 0.58-1.25) and 1-year all-cause mortality (HRunadj: 0.88; 95% CI: 0.64-1.22) in the crude cohort. After adjusting for selection and immortal time bias, IE-CS compared with IE-AB was also not associated with lower mortality rates for in-hospital mortality (HRadj: 0.92; 95% CI: 0.80-1.05) and 1-year all-cause mortality (HRadj: 0.95; 95% CI: 0.84-1.07). Results remained similar when patients with and without TAVI prosthesis involvement were analyzed separately. Predictors for in-hospital and 1-year all-cause mortality included logistic EuroSCORE I, Staphylococcus aureus, acute renal failure, persistent bacteremia, and septic shock. CONCLUSIONS: In this registry, the majority of patients with TAVI-IE were treated with antibiotics alone. Cardiac surgery was not associated with an improved all-cause in-hospital or 1-year mortality. The high mortality of patients with TAVI-IE was strongly linked to patients' characteristics, pathogen, and IE-related complications.

Perivalvular Extension of Infective Endocarditis After Transcatheter Aortic Valve Replacement.

BACKGROUND: Infective endocarditis (IE) following transcatheter aortic valve replacement (TAVR) has been associated with a dismal prognosis. However, scarce data exist on IE perivalvular extension (PEE) in such patients. METHODS: This multicenter study included 579 patients who had the diagnosis of definite IE at a median of 171 (53-421) days following TAVR. PEE was defined as the presence of an intracardiac abscess, pseudoaneurysm, or fistula. RESULTS: A total of 105 patients (18.1%) were diagnosed with PEE (perivalvular abscess, pseudoaneurysm, fistula, or a combination in 87, 7, 7, and 4 patients, respectively). A history of chronic kidney disease (adjusted odds ratio [ORadj], 2.08; 95% confidence interval [CI]: 1.27-3.41; P = .003) and IE secondary to coagulase-negative staphylococci (ORadj, 2.71; 95% CI: 1.57-4.69; P < .001) were associated with an increased risk of PEE. Surgery was performed at index IE episode in 34 patients (32.4%) with PEE (vs 15.2% in patients without PEE, P < .001). In-hospital and 2-year mortality rates among PEE-IE patients were 36.5% and 69.4%, respectively. Factors independently associated with an increased mortality were the occurrence of other complications (stroke post-TAVR, acute renal failure, septic shock) and the lack of surgery at index IE hospitalization (padj < 0.05 for all). CONCLUSIONS: PEE occurred in about one-fifth of IE post-TAVR patients, with the presence of coagulase-negative staphylococci and chronic kidney disease determining an increased risk. Patients with PEE-IE exhibited high early and late mortality rates, and surgery during IE hospitalization seemed to be associated with better outcomes.

Infective Endocarditis Caused by Staphylococcus aureus After Transcatheter Aortic Valve Replacement.

BACKGROUND: Staphylococcus aureus (SA) has been extensively studied as causative microorganism of surgical prosthetic-valve infective endocarditis (IE). However, scarce evidence exists on SA IE after transcatheter aortic valve replacement (TAVR). METHODS: Data were obtained from the Infectious Endocarditis After TAVR International Registry, including patients with definite IE after TAVR from 59 centres in 11 countries. Patients were divided into 2 groups according to microbiologic etiology: non-SA IE vs SA IE. RESULTS: SA IE was identified in 141 patients out of 573 (24.6%), methicillin-sensitive SA in most cases (115/141, 81.6%). Self-expanding valves were more common than balloon-expandable valves in patients presenting with early SA IE. Major bleeding and sepsis complicating TAVR, neurologic symptoms or systemic embolism at admission, and IE with cardiac device involvement (other than the TAVR prosthesis) were associated with SA IE (P < 0.05 for all). Among patients with IE after TAVR, the likelihood of SA IE increased from 19% in the absence of those risk factors to 84.6% if ≥ 3 risk factors were present. In-hospital (47.8% vs 26.9%; P < 0.001) and 2-year (71.5% vs 49.6%; P < 0.001) mortality rates were higher among patients with SA IE vs non-SA IE. Surgery at the time of index SA IE episode was associated with lower mortality at follow-up compared with medical therapy alone (adjusted hazard ratio 0.46, 95% CI 0.22-0.96; P = 0.038). CONCLUSIONS: SA IE represented approximately 25% of IE cases after TAVR and was associated with very high in-hospital and late mortality. The presence of some features determined a higher likelihood of SA IE and could help to orientate early antibiotic regimen selection. Surgery at index SA IE was associated with improved outcomes, and its role should be evaluated in future studies.

Left ventricular global longitudinal strain assessment in patients with takotsubo cardiomyopathy: a call for an echocardiography-based classification.

BACKGROUND: Takotsubo cardiomyopathy (TTC) is classified into 4 types depending on the anatomical area affected identified on gross visual assessment. We have sought to understand if it is feasible and advantageous to use left ventricular global longitudinal strain (LVGLS), LV segmental longitudinal strain and right ventricle free wall strain (RVFWS) to classify TTC. METHODS: We conducted a retrospective observational study on twenty-five patients who meet the Modified Mayo Clinic Criteria for TTC [1]. Two independent reviewers performed strain analysis, they were both blinded to patient's diagnosed classification and outcomes. RESULTS: Based on classification by traditional assessment the 92% (N.=23) were diagnosed with typical TTC, indicating apical involvement. The entire LV was affected, 67% (N.=16) had abnormal strain (STE>-18) in all three LV regions (base, mid-ventricle and apex). Seventy-one percent of patients (N.=17) had abnormal LVGLS (>-18). Abnormal strain across all three LV regions was associated with higher prevalence (70%, N.=8 Vs 30%, N.=4, respectively) of composite cardiovascular events and longer length of hospital stay. There was a statistically significant difference in average length of hospital stay in those patients who had abnormal strain in all three regions compared to those that did not have abnormal strain across all three regions (8 days compared to 3.44 days, P=0.02). CONCLUSIONS: A new classification of TCC based on strain analysis should be developed. The traditional model is arbitrary; it fails to recognize that in most patients the entire LV is affect, it does not have prognostic significance and the most prevalent typical variant indicates apical involvement. Our study suggests that the entire LV is affected, and strain analysis has prognostic significance.

Polarized Raman spectroscopy in low-symmetry 2D materials: angle-resolved experiments and complex number tensor elements.

In this perspective review, we discuss the power of polarized Raman spectroscopy to study optically anisotropic 2D materials, belonging to the orthorhombic, monoclinic and triclinic crystal families. We start by showing that the polarization dependence of the peak intensities is described by the Raman tensor that is unique for each phonon mode, and then we discuss how to determine the tensor elements from the angle-resolved polarized measurements by analyzing the intensities in both the parallel- and cross-polarized scattering configurations. We present specific examples of orthorhombic black phosphorus and monoclinic 1T'-MoTe2, where the Raman tensors have null elements and their principal axes coincide with the crystallographic ones, followed by a discussion on the results for triclinic ReS2 and ReSe2, where the axes of the Raman tensor do not coincide with the crystallographic axes and all elements are non-zero. We show that the Raman tensor elements are, in general, given by complex numbers and that phase differences between tensor elements are needed to describe the experimental results. We discuss the dependence of the Raman tensors on the excitation laser energy and thickness of the sample within the framework of the quantum model for the Raman intensities. We show that the wavevector dependence of the electron-phonon interaction is essential for explaining the distinct Raman tensor for each phonon mode. Finally, we close with our concluding remarks and perspectives to be explored using angle-resolved polarized Raman spectroscopy in optically anisotropic 2D materials.

Coronary Artery Disease in Patients with Aortic Stenosis and Transcatheter Aortic Valve Implantation: Implications for Management.

Aortic valve stenosis (AS) is the most common valvular heart disease among elderly patients. Since the pathophysiology of degenerative AS shares common pathways with atherosclerotic disease, the severity of AS in the elderly population is often concurrent to the presence of coronary artery disease (CAD). Although surgical aortic valve replacement has been the standard treatment for severe AS, the high operative morbidity and mortality in complex and fragile patients was the trigger to develop less invasive techniques. Transcatheter aortic valve implantation (TAVI) has been posed as the standard of care for elderly patients with severe AS with various risk profiles, which has meant that the concomitant management of CAD has become a crucial issue in such patients. Given the lack of randomised controlled trials evaluating the management of CAD in TAVI patients, most of the recommendations are based on retrospective cohort studies so that the Heart Team approach - together with an assessment of multiple parameters including symptoms and clinical characteristics, invasive and non-invasive ischaemic burden and anatomy - are crucial for the proper management of these patients. This article provides a review of current knowledge about assessment and therapeutic approaches for CAD and severe AS in patients undergoing TAVI.

Temporal Trends, Characteristics, and Outcomes of Infective Endocarditis After Transcatheter Aortic Valve Replacement

BACKGROUND: Procedural improvements combined with the contemporary clinical profile of patients undergoing transcatheter aortic valve replacement (TAVR) may have influenced the incidence and outcomes of infective endocarditis (IE) following TAVR. We aimed to determine the temporal trends, characteristics, and outcomes of IE post-TAVR. METHODS: Observational study including 552 patients presenting definite IE post-TAVR. Patients were divided in 2 groups according to the timing of TAVR (historical cohort [HC]: before 2014; contemporary cohort [CC]: after 2014). RESULTS: Overall incidence rates of IE were similar in both cohorts (CC vs HC: 5.45 vs 6.52 per 1000 person-years; P = .12), but the rate of early IE was lower in the CC (2.29‰ vs 4.89‰, P < .001). Enterococci were the most frequent microorganism. Most patients presented complicated IE (CC: 67.7%; HC: 69.6%; P = .66), but the rate of surgical treatment remained low (CC: 20.7%; HC: 17.3%; P = .32). The CC exhibited lower rates of in-hospital acute kidney injury (35.1% vs 44.6%; P = .036) and in-hospital (26.6% vs 36.4%; P = .016) and 1-year (37.8% vs 53.5%; P < .001) mortality. Higher logistic EuroScore, Staphylococcus aureus etiology, and complications (stroke, heart failure, and acute renal failure) were associated with in-hospital mortality in multivariable analyses (P < .05 for all). CONCLUSIONS: Although overall IE incidence has remained stable, the incidence of early IE has declined in recent years. The microorganism, high rate of complications, and very low rate of surgical treatment remained similar. In-hospital and 1-year mortality rates were high but progressively decreased over time.