Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 105
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Nature ; 603(7900): 247-252, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35264760

RESUMEN

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.

2.
Proc Natl Acad Sci U S A ; 121(4): e2314454121, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38232283

RESUMEN

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.

3.
Nano Lett ; 22(7): 2851-2858, 2022 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-35311277

RESUMEN

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.

4.
Clin Infect Dis ; 75(4): 638-646, 2022 09 10.
Artículo en Inglés | MEDLINE | ID: mdl-34894124

RESUMEN

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.


Asunto(s)
Aneurisma Falso , Endocarditis Bacteriana , Endocarditis , Insuficiencia Renal Crónica , Reemplazo de la Válvula Aórtica Transcatéter , Absceso , Aneurisma Falso/complicaciones , Aneurisma Falso/cirugía , Coagulasa , Endocarditis/epidemiología , Endocarditis/etiología , Endocarditis/cirugía , Endocarditis Bacteriana/epidemiología , Endocarditis Bacteriana/etiología , Endocarditis Bacteriana/cirugía , Humanos , Insuficiencia Renal Crónica/complicaciones , Factores de Riesgo , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos
5.
Clin Infect Dis ; 73(11): e3750-e3758, 2021 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-33733675

RESUMEN

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.


Asunto(s)
Endocarditis Bacteriana , Endocarditis , Reemplazo de la Válvula Aórtica Transcatéter , Endocarditis/epidemiología , Endocarditis/etiología , Endocarditis/cirugía , Endocarditis Bacteriana/epidemiología , Endocarditis Bacteriana/etiología , Endocarditis Bacteriana/cirugía , Humanos , Incidencia , Complicaciones Posoperatorias/epidemiología , Factores de Riesgo , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos , Resultado del Tratamiento
6.
Catheter Cardiovasc Interv ; 98(3): E370-E378, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33904638

RESUMEN

OBJECTIVES: We aimed to explore angiographic patterns and in-hospital outcomes of patients with concomitant coronavirus disease-19 (COVID-19) and myocardial infarction (MI). BACKGROUND: Patients with COVID-19 may experience MI during the course of the viral infection. However, this association is currently poorly understood. METHODS: This is a multicenter prospective study of consecutive patients with concomitant COVID-19 and MI who underwent coronary angiography. Quantitative and qualitative coronary angiography were analyzed by two observers in an independent core lab. RESULTS: A total of 152 patients were included, of whom 142 (93.4%) had COVID-19 diagnosis confirmation. The median time between symptom onset and hospital admission was 5 (1-10) days. A total of 83 (54.6%) patients presented with ST-elevation MI. The median angiographic Syntax score was 16 (9.0-25.3) and 69.0% had multi-vessel disease. At least one complex lesion was found in 73.0% of patients, 51.3% had a thrombus containing lesion, and 57.9% had myocardial blush grades 0/1. The overall in-hospital mortality was 23.7%. ST-segment elevation MI presentation and baseline myocardial blush grades 0 or 1 were independently associated with a higher risk of death (HR 2.75, 95%CI 1.30-5.80 and HR 3.73, 95%CI 1.61-8.61, respectively). CONCLUSIONS: Patients who have a MI in the context of ongoing COVID-19 mostly present complex coronary morphologies, implying a background of prior atherosclerotic disease superimposed on a thrombotic milieu. The in-hospital prognosis is poor with a markedly high mortality, prompting further investigation to better clarify this newly described condition.


Asunto(s)
COVID-19 , Infarto del Miocardio , Intervención Coronaria Percutánea , Prueba de COVID-19 , Angiografía Coronaria , Mortalidad Hospitalaria , Humanos , Infarto del Miocardio/diagnóstico por imagen , Estudios Prospectivos , SARS-CoV-2 , Resultado del Tratamiento
7.
Phys Chem Chem Phys ; 23(48): 27103-27123, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34859800

RESUMEN

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.

8.
Eur Heart J ; 39(8): 687-695, 2018 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-29020413

RESUMEN

Aims: There are limited data on coronary obstruction following transcatheter valve-in-valve (ViV) implantation inside failed aortic bioprostheses. The objectives of this study were to determine the incidence, predictors, and clinical outcomes of coronary obstruction in transcatheter ViV procedures. Methods and results: A total of 1612 aortic procedures from the Valve-in-Valve International Data (VIVID) Registry were evaluated. Data were subject to centralized blinded corelab computed tomography (CT) analysis in a subset of patients. The virtual transcatheter valve to coronary ostium distance (VTC) was determined. A total of 37 patients (2.3%) had clinically evident coronary obstruction. Baseline clinical characteristics in the coronary obstruction patients were similar to controls. Coronary obstruction was more common in stented bioprostheses with externally mounted leaflets or stentless bioprostheses than in stented with internally mounted leaflets bioprostheses (6.1% vs. 3.7% vs. 0.8%, respectively; P < 0.001). CT measurements were obtained in 20 (54%) and 90 (5.4%) of patients with and without coronary obstruction, respectively. VTC distance was shorter in coronary obstruction patients in relation to controls (3.24 ± 2.22 vs. 6.30 ± 2.34, respectively; P < 0.001). Using multivariable analysis, the use of a stentless or stented bioprosthesis with externally mounted leaflets [odds ratio (OR): 7.67; 95% confidence interval (CI): 3.14-18.7; P < 0.001] associated with coronary obstruction for the global population. In a second model with CT data, a shorter VTC distance predicted this complication (OR: 0.22 per 1 mm increase; 95% CI: 0.09-0.51; P < 0.001), with an optimal cut-off level of 4 mm (area under the curve: 0.943; P < 0.001). Coronary obstruction was associated with a high 30-day mortality (52.9% vs. 3.9% in the controls, respectively; P < 0.001). Conclusion: Coronary obstruction following aortic ViV procedures is a life-threatening complication that occurred more frequently in patients with prior stentless or stented bioprostheses with externally mounted leaflets and in those with a short VTC.


Asunto(s)
Oclusión Coronaria/epidemiología , Tomografía Computarizada Multidetector/métodos , Falla de Prótesis/efectos adversos , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos , Anciano , Oclusión Coronaria/diagnóstico por imagen , Oclusión Coronaria/etiología , Femenino , Prótesis Valvulares Cardíacas , Humanos , Incidencia , Masculino , Análisis Multivariante , Sistema de Registros , Factores de Riesgo
9.
Circulation ; 131(5): 469-77, 2015 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-25466975

RESUMEN

BACKGROUND: This study sought to evaluate the prevalence of previously undiagnosed arrhythmias in candidates for transcatheter aortic valve replacement (TAVR) and to determine the impact on therapy changes and arrhythmic events after the procedure. METHODS AND RESULTS: A total of 435 candidates for TAVR underwent 24-hour continuous ECG monitoring the day before the procedure. Newly diagnosed arrhythmias were observed in 70 patients (16.1%) before TAVR: paroxysmal atrial fibrillation (AF)/atrial tachycardia (AT) in 28, advanced atrioventricular block or severe bradycardia in 24, nonsustained ventricular tachycardia in 26, and intermittent left bundle-branch block in 3 patients. All arrhythmic events but one were asymptomatic and led to a therapy change in 43% of patients. In patients without known AF/AT, the occurrence of AF/AT during 24-hour ECG recording was associated with a higher rate of 30-day cerebrovascular events (7.1% versus 0.4%; P=0.030). Among the 53 patients with new-onset AF/AT after TAVR, 30.2% had newly diagnosed paroxysmal AF/AT before the procedure. In patients who needed permanent pacemaker implantation after the procedure (n=35), 31.4% had newly diagnosed advanced atrioventricular block or severe bradycardia before TAVR. New-onset persistent left bundle-branch block after TAVR occurred in 37 patients, 8.1% of whom had intermittent left bundle-branch block before the procedure. CONCLUSIONS: Newly diagnosed arrhythmias were observed in approximately a fifth of TAVR candidates, led to a higher rate of cerebrovascular events, and accounted for a third of arrhythmic events after the procedure. This high arrhythmia burden highlights the importance of an early diagnosis of arrhythmic events in such patients to implement the appropriate therapeutic measures earlier.


Asunto(s)
Estenosis de la Válvula Aórtica/diagnóstico , Arritmias Cardíacas/diagnóstico , Costo de Enfermedad , Electrocardiografía Ambulatoria/tendencias , Índice de Severidad de la Enfermedad , Reemplazo de la Válvula Aórtica Transcatéter/tendencias , Anciano , Anciano de 80 o más Años , Estenosis de la Válvula Aórtica/fisiopatología , Estenosis de la Válvula Aórtica/cirugía , Arritmias Cardíacas/fisiopatología , Comprensión , Femenino , Humanos , Masculino , Cuidados Preoperatorios/tendencias , Resultado del Tratamiento
10.
JAMA ; 316(10): 1083-92, 2016 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-27623462

RESUMEN

IMPORTANCE: Limited data exist on clinical characteristics and outcomes of patients who had infective endocarditis after undergoing transcatheter aortic valve replacement (TAVR). OBJECTIVE: To determine the associated factors, clinical characteristics, and outcomes of patients who had infective endocarditis after TAVR. DESIGN, SETTING, AND PARTICIPANTS: The Infectious Endocarditis after TAVR International Registry included patients with definite infective endocarditis after TAVR from 47 centers from Europe, North America, and South America between June 2005 and October 2015. EXPOSURE: Transcatheter aortic valve replacement for incidence of infective endocarditis and infective endocarditis for in-hospital mortality. MAIN OUTCOMES AND MEASURES: Infective endocarditis and in-hospital mortality after infective endocarditis. RESULTS: A total of 250 cases of infective endocarditis occurred in 20 006 patients after TAVR (incidence, 1.1% per person-year; 95% CI, 1.1%-1.4%; median age, 80 years; 64% men). Median time from TAVR to infective endocarditis was 5.3 months (interquartile range [IQR], 1.5-13.4 months). The characteristics associated with higher risk of progressing to infective endocarditis after TAVR was younger age (78.9 years vs 81.8 years; hazard ratio [HR], 0.97 per year; 95% CI, 0.94-0.99), male sex (62.0% vs 49.7%; HR, 1.69; 95% CI, 1.13-2.52), diabetes mellitus (41.7% vs 30.0%; HR, 1.52; 95% CI, 1.02-2.29), and moderate to severe aortic regurgitation (22.4% vs 14.7%; HR, 2.05; 95% CI, 1.28-3.28). Health care-associated infective endocarditis was present in 52.8% (95% CI, 46.6%-59.0%) of patients. Enterococci species and Staphylococcus aureus were the most frequently isolated microorganisms (24.6%; 95% CI, 19.1%-30.1% and 23.3%; 95% CI, 17.9%-28.7%, respectively). The in-hospital mortality rate was 36% (95% CI, 30.0%-41.9%; 90 deaths; 160 survivors), and surgery was performed in 14.8% (95% CI, 10.4%-19.2%) of patients during the infective endocarditis episode. In-hospital mortality was associated with a higher logistic EuroSCORE (23.1% vs 18.6%; odds ratio [OR], 1.03 per 1% increase; 95% CI, 1.00-1.05), heart failure (59.3% vs 23.7%; OR, 3.36; 95% CI, 1.74-6.45), and acute kidney injury (67.4% vs 31.6%; OR, 2.70; 95% CI, 1.42-5.11). The 2-year mortality rate was 66.7% (95% CI, 59.0%-74.2%; 132 deaths; 115 survivors). CONCLUSIONS AND RELEVANCE: Among patients undergoing TAVR, younger age, male sex, history of diabetes mellitus, and moderate to severe residual aortic regurgitation were significantly associated with an increased risk of infective endocarditis. Patients who developed endocarditis had high rates of in-hospital mortality and 2-year mortality.


Asunto(s)
Endocarditis Bacteriana/epidemiología , Endocarditis/etiología , Mortalidad Hospitalaria/tendencias , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos , Factores de Edad , Anciano , Endocarditis Bacteriana/etiología , Femenino , Estudios de Seguimiento , Insuficiencia Cardíaca , Humanos , Masculino , Oportunidad Relativa , Sistema de Registros , Factores de Riesgo , Factores Sexuales , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/etiología , Staphylococcus aureus , Resultado del Tratamiento
11.
Circulation ; 129(11): 1233-43, 2014 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-24370552

RESUMEN

BACKGROUND: Very few data exist on the clinical impact of permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation. The objective of this study was to assess the impact of PPI after transcatheter aortic valve implantation on late outcomes in a large cohort of patients. METHODS AND RESULTS: A total of 1556 consecutive patients without prior PPI undergoing transcatheter aortic valve implantation were included. Of them, 239 patients (15.4%) required a PPI within the first 30 days after transcatheter aortic valve implantation. At a mean follow-up of 22±17 months, no association was observed between the need for 30-day PPI and all-cause mortality (hazard ratio, 0.98; 95% confidence interval, 0.74-1.30; P=0.871), cardiovascular mortality (hazard ratio, 0.81; 95% confidence interval, 0.56-1.17; P=0.270), and all-cause mortality or rehospitalization for heart failure (hazard ratio, 1.00; 95% confidence interval, 0.77-1.30; P=0.980). A lower rate of unexpected (sudden or unknown) death was observed in patients with PPI (hazard ratio, 0.31; 95% confidence interval, 0.11-0.85; P=0.023). Patients with new PPI showed a poorer evolution of left ventricular ejection fraction over time (P=0.017), and new PPI was an independent predictor of left ventricular ejection fraction decrease at the 6- to 12-month follow-up (estimated coefficient, -2.26; 95% confidence interval, -4.07 to -0.44; P=0.013; R(2)=0.121). CONCLUSIONS: The need for PPI was a frequent complication of transcatheter aortic valve implantation, but it was not associated with any increase in overall or cardiovascular death or rehospitalization for heart failure after a mean follow-up of ≈2 years. Indeed, 30-day PPI was a protective factor for the occurrence of unexpected (sudden or unknown) death. However, new PPI did have a negative effect on left ventricular function over time.


Asunto(s)
Válvula Aórtica/cirugía , Cateterismo Cardíaco/tendencias , Implantación de Prótesis de Válvulas Cardíacas/tendencias , Marcapaso Artificial/tendencias , Función Ventricular Izquierda/fisiología , Anciano , Anciano de 80 o más Años , Válvula Aórtica/patología , Cateterismo Cardíaco/mortalidad , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Implantación de Prótesis de Válvulas Cardíacas/mortalidad , Humanos , Masculino , Estudios Prospectivos , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento
12.
Eur J Clin Invest ; 45(2): 215-25, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25556629

RESUMEN

AIMS: To review the safety and feasibility of a transradial (TR) approach during transcatheter structural or congenital heart disease interventions when utilized as either as a primary or secondary arterial access site. METHODS AND RESULTS: Studies and case reports published between 2002 and 2014 utilizing the TR access during transcatheter structural and congenital heart disease interventions during alcohol septal ablation (ASA), ventricular septal defect (VSD), renal denervation (RD), paravalvular leak (PVL) closure, transcatheter aortic valve implantation (TAVI, secondary access) and endovascular repair of aortic coarctation (ERAC, secondary access) were evaluated. Access-site (femoral vs. TR) vascular and bleeding complications were assessed. Femoral access complications ranged from 0.16% to 40%, with an overall incidence of 2.2% (56/2521). There were 18 reports or studies specifically evaluating the utility of TR access in the context of transcatheter structural heart disease interventions (ASA: 3; VSD: 1; RD: 3; PVL closure: 1; TAVI: 7, ERAC: 3). The use of TR access either as primary or secondary access site was feasible and allowed the completion of the procedure in all cases. The overall incidence of access-site complications following a TR approach was 0.5% (2/406 patients), with no major vascular or bleeding complications. CONCLUSIONS: A TR approach during transcatheter structural heart disease interventions appears to be a safe, effective means of delivering high procedural success accompanied by lower bleeding complications compared with the transfemoral approach.


Asunto(s)
Angioplastia/métodos , Cateterismo Cardíaco/métodos , Cardiopatías Congénitas/cirugía , Técnicas de Ablación/métodos , Angioplastia/efectos adversos , Cateterismo Cardíaco/efectos adversos , Cardiomiopatía Hipertrófica/terapia , Etanol/uso terapéutico , Estudios de Factibilidad , Femenino , Defectos del Tabique Interatrial/cirugía , Humanos , Riñón/inervación , Masculino , Persona de Mediana Edad , Seguridad del Paciente , Solventes/uso terapéutico , Simpatectomía/métodos , Reemplazo de la Válvula Aórtica Transcatéter/métodos
13.
Eur Heart J ; 35(38): 2685-96, 2014 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-24796337

RESUMEN

AIM: The aim of this study was to determine the effects of advanced chronic kidney disease (CKD) on early and late outcomes after transcatheter aortic valve implantation (TAVI), and to evaluate the predictive factors of poorer outcomes in such patients. METHODS AND RESULTS: This was a multicentre study including a total of 2075 consecutive patients who had undergone TAVI. Patients were grouped according the estimated glomerular filtration rate as follows: CKD stage 1-2 (≥60 mL/min/1.73 m(2); n = 950), stage 3 (30-59 mL/min/1.73 m(2); n = 924), stage 4 (15-29 mL/min/1.73 m(2); n = 134) and stage 5 (<15 mL/min/1.73 m² or dialysis; n = 67). Clinical outcomes were evaluated at 30-days and at follow-up (median of 15 [6-29] months) and defined according to the VARC criteria. Advanced CKD (stage 4-5) was an independent predictor of 30-day major/life-threatening bleeding (P = 0.001) and mortality (P = 0.027), and late overall, cardiovascular and non-cardiovascular mortality (P < 0.01 for all). Pre-existing atrial fibrillation (HR: 2.29, 95% CI: 1.47-3.58, P = 0.001) and dialysis therapy (HR: 1.86, 95% CI: 1.17-2.97, P = 0.009) were the predictors of mortality in advanced CKD patients, with a mortality rate as high as 71% at 1-year follow-up in those patients with these 2 factors. Advanced CKD patients who had survived at 1-year follow-up exhibited both a significant improvement in NYHA class (P < 0.001) and no deterioration in valve hemodynamics (P = NS for changes in mean gradient and valve area over time). CONCLUSIONS: Advanced CKD was associated with a higher rate of early and late mortality and bleeding events following TAVI, with AF and dialysis therapy determining a higher risk in these patients. The mortality rate of patients with both factors was unacceptably high and this should be taken into account in the clinical decision-making process in this challenging group of patients.


Asunto(s)
Estenosis de la Válvula Aórtica/cirugía , Insuficiencia Renal Crónica/complicaciones , Reemplazo de la Válvula Aórtica Transcatéter/métodos , Anciano , Estenosis de la Válvula Aórtica/complicaciones , Estenosis de la Válvula Aórtica/mortalidad , Femenino , Hemodinámica/fisiología , Humanos , Estimación de Kaplan-Meier , Tiempo de Internación , Masculino , Hemorragia Posoperatoria/etiología , Hemorragia Posoperatoria/mortalidad , Pronóstico , Insuficiencia Renal Crónica/mortalidad , Accidente Cerebrovascular/etiología , Accidente Cerebrovascular/mortalidad , Reemplazo de la Válvula Aórtica Transcatéter/instrumentación , Reemplazo de la Válvula Aórtica Transcatéter/mortalidad , Resultado del Tratamiento
14.
Circulation ; 128(3): 244-53, 2013 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-23748467

RESUMEN

BACKGROUND: Aortic root rupture is a major concern with balloon-expandable transcatheter aortic valve replacement (TAVR). We sought to identify predictors of aortic root rupture during balloon-expandable TAVR by using multidetector computed tomography. METHODS AND RESULTS: Thirty-one consecutive patients who experienced left ventricular outflow tract (LVOT)/annular/aortic contained/noncontained rupture during TAVR were collected from 16 centers. A caliper-matched sample of 31 consecutive patients without annular rupture, who underwent pre-TAVR multidetector computed tomography served as a control group. Multidetector computed tomography assessment included short- and long-axis diameters and cross-sectional area of the sinotubular junction, annulus, and LVOT, and the presence, location, and extent of calcification of the LVOT, as well. There were no significant differences between the 2 groups in any preoperative clinical and echocardiographic variables. Aortic root rupture was identified in 20 patients and periaortic hematoma in 11. Patients with root rupture had a higher degree of subannular/LVOT calcification quantified by the Agatston score (181.2±211.0 versus 22.5±37.6, P<0.001), and a higher frequency of ≥20% annular area oversizing (79.4% versus 29.0%, P<0.001) and balloon postdilatation (22.6% versus 0.0%, P=0.005). In conditional logistic regression analysis for the matched data, moderate/severe LVOT/subannular calcifications (odds ratio, 10.92; 95% confidence interval, 3.23-36.91; P<0.001) and prosthesis oversizing ≥20% (odds ratio, 8.38; 95% confidence interval, 2.67-26.33; P<0.001) were associated with aortic root contained/noncontained rupture. CONCLUSIONS: This study demonstrates that LVOT calcification and aggressive annular area oversizing are associated with an increased risk of aortic root rupture during TAVR with balloon-expandable prostheses. Larger studies are warranted to confirm these findings.


Asunto(s)
Angioplastia de Balón/efectos adversos , Rotura de la Aorta/etiología , Estenosis de la Válvula Aórtica/terapia , Cateterismo Cardíaco , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Anciano , Anciano de 80 o más Años , Rotura de la Aorta/diagnóstico por imagen , Rotura de la Aorta/epidemiología , Válvula Aórtica/diagnóstico por imagen , Estenosis de la Válvula Aórtica/diagnóstico por imagen , Estenosis de la Válvula Aórtica/epidemiología , Calcinosis/complicaciones , Calcinosis/diagnóstico por imagen , Calcinosis/epidemiología , Estudios de Cohortes , Femenino , Implantación de Prótesis de Válvulas Cardíacas/métodos , Humanos , Modelos Logísticos , Masculino , Valor Predictivo de las Pruebas , Factores de Riesgo , Tomografía Computarizada por Rayos X
15.
Catheter Cardiovasc Interv ; 82(7): E856-63, 2013 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-23239630

RESUMEN

INTRODUCTION: The safety and effectiveness of drug-eluting stent (DES) compared with bare metal stents (BMS) for the treatment of saphenous vein graft (SVG) disease is controversial, especially because of the lack of long-term follow-up. The aim of this study was to address the late outcome of DES versus BMS for the treatment of SVG lesions. METHODS: A matched, case-control study included 82 patients in each group. Patients groups were matched by gender, age, clinical presentation, and diabetes. The primary study end point was occurrence of major adverse cardiovascular events (MACE). Secondary end points included death, cardiac death, myocardial infarction (MI), and target vessel revascularization (TVR). RESULTS: Clinical and angiographic characteristics were similar between the groups. At 6 months, TVR (hazard ratio [HR] 6.12, 95% confidence interval [CI] 1.39 to 26.93, P = 0.05), and MACE (HR 2.54, 95% CI 1.08 to 5.98, P = 0.04) were higher in the BMS group. At 4 years the risks of MI (P = 0.21), TVR (P = 0.99), and MACE (P = 0.21) were similar between both groups. However, the rates of death (HR 2.74, 95% CI 1.11 to 6.74, P = 0.04) and cardiac death (HR 4.26, 95% CI 1.59 to 11.35, P = 0.01) were significantly higher in the BMS group. CONCLUSIONS: These results suggest that the use of DES compared with BMS in the treatment of SVG lesions reduces TVR and MACE at 6 months of follow-up, a benefit that was lost over the next 3-4 years.


Asunto(s)
Puente de Arteria Coronaria/efectos adversos , Stents Liberadores de Fármacos , Oclusión de Injerto Vascular/terapia , Metales , Intervención Coronaria Percutánea/instrumentación , Vena Safena/cirugía , Stents , Anciano , Angiografía Coronaria , Puente de Arteria Coronaria/mortalidad , Femenino , Oclusión de Injerto Vascular/diagnóstico , Oclusión de Injerto Vascular/etiología , Oclusión de Injerto Vascular/mortalidad , Oclusión de Injerto Vascular/fisiopatología , Humanos , Estimación de Kaplan-Meier , Masculino , Análisis por Apareamiento , Persona de Mediana Edad , Infarto del Miocardio/etiología , Intervención Coronaria Percutánea/efectos adversos , Intervención Coronaria Percutánea/mortalidad , Diseño de Prótesis , Estudios Retrospectivos , Factores de Riesgo , Vena Safena/diagnóstico por imagen , Vena Safena/fisiopatología , Factores de Tiempo , Resultado del Tratamiento
16.
J Card Surg ; 28(5): 506-9, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23869469

RESUMEN

We report two cases of high-risk aortic stenosis treated with the SAPIEN 3 valve. This is the first procedure performed with this type of valve through the transapical approach. This new balloon-expandable valve incorporates a lower profile cobalt-chromium stent and an additional outer skirt to enhance paravalvular sealing. The procedure was performed without complications and no paravalvular leak was detected in control echocardiogram at follow-up.


Asunto(s)
Estenosis de la Válvula Aórtica/cirugía , Válvula Aórtica/cirugía , Cateterismo Cardíaco , Implantación de Prótesis de Válvulas Cardíacas/métodos , Prótesis Valvulares Cardíacas , Anciano , Anciano de 80 o más Años , Válvula Aórtica/diagnóstico por imagen , Estenosis de la Válvula Aórtica/diagnóstico por imagen , Cromo , Cobalto , Ecocardiografía , Estudios de Seguimiento , Humanos , Masculino , Riesgo , Stents , Cirugía Asistida por Computador , Resultado del Tratamiento
17.
ACS Nano ; 17(16): 15883-15892, 2023 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-37556765

RESUMEN

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.

18.
J Am Soc Echocardiogr ; 36(5): 504-513, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36535625

RESUMEN

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.


Asunto(s)
Fibrilación Atrial , Remodelación Atrial , Intervención Coronaria Percutánea , Infarto del Miocardio con Elevación del ST , Humanos , Femenino , Masculino , Infarto del Miocardio con Elevación del ST/diagnóstico , Infarto del Miocardio con Elevación del ST/terapia , Intervención Coronaria Percutánea/métodos , Atrios Cardíacos/diagnóstico por imagen , Función Ventricular Izquierda , Remodelación Ventricular
19.
JACC Cardiovasc Interv ; 16(17): 2153-2164, 2023 09 11.
Artículo en Inglés | MEDLINE | ID: mdl-37704301

RESUMEN

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.


Asunto(s)
Intervención Coronaria Percutánea , Reemplazo de la Válvula Aórtica Transcatéter , Humanos , Femenino , Anciano , Anciano de 80 o más Años , Masculino , Intervención Coronaria Percutánea/efectos adversos , Reemplazo de la Válvula Aórtica Transcatéter/efectos adversos , Resultado del Tratamiento , Hemorragia/inducido químicamente , Catéteres
20.
JACC Cardiovasc Interv ; 16(21): 2615-2627, 2023 11 13.
Artículo en Inglés | MEDLINE | ID: mdl-37968032

RESUMEN

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.


Asunto(s)
Fibrilación Atrial , Bioprótesis , Implantación de Prótesis de Válvulas Cardíacas , Prótesis Valvulares Cardíacas , Humanos , Femenino , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Masculino , Válvula Mitral/diagnóstico por imagen , Válvula Mitral/cirugía , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Constricción Patológica/etiología , Resultado del Tratamiento , Cateterismo Cardíaco/efectos adversos , Hemodinámica , Sistema de Registros , Diseño de Prótesis
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA