Using pressure to unravel the structure-dynamic-disorder relationship in metal halide perovskites.

The exceptional optoelectronic properties of metal halide perovskites (MHPs) are presumed to arise, at least in part, from the peculiar interplay between the inorganic metal-halide sublattice and the atomic or molecular cations enclosed in the cage voids. The latter can exhibit a roto-translative dynamics, which is shown here to be at the origin of the structural behavior of MHPs as a function of temperature, pressure and composition. The application of high hydrostatic pressure allows for unraveling the nature of the interaction between both sublattices, characterized by the simultaneous action of hydrogen bonding and steric hindrance. In particular, we find that under the conditions of unleashed cation dynamics, the key factor that determines the structural stability of MHPs is the repulsive steric interaction rather than hydrogen bonding. Taking as example the results from pressure and temperature-dependent photoluminescence and Raman experiments on MAPbBr[Formula: see text] but also considering the pertinent MHP literature, we provide a general picture about the relationship between the crystal structure and the presence or absence of cationic dynamic disorder. The reason for the structural sequences observed in MHPs with increasing temperature, pressure, A-site cation size or decreasing halide ionic radius is found principally in the strengthening of the dynamic steric interaction with the increase of the dynamic disorder. In this way, we have deepened our fundamental understanding of MHPs; knowledge that could be coined to improve performance in future optoelectronic devices based on this promising class of semiconductors.

Effect of Flu Vaccination on Severity and Outcome of Heart Failure Decompensations.

OBJECTIVE: To investigate the relationship of seasonal flu vaccination with the severity of decompensation and long-term outcomes of patients with heart failure (HF). METHODS: We analyzed 6147 consecutively enrolled patients with decompensated HF who presented to 33 Spanish emergency departments (EDs) during January and February of 2018 and 2019, grouped according to seasonal flu vaccination status. The severity of HF decompensation was assessed by the Multiple Estimation of Risk Based on the Emergency Department Spanish Score in Patients With Acute Heart Failure (MEESSI-AHF) + MEESSI scale, need of hospitalization and in-hospital all-cause mortality. The long-term outcomes analyzed were 90-day postdischarge adverse events and 90-day all-cause death. Associations between vaccination, HF decompensation severity and long-term outcomes were explored by unadjusted and adjusted logistic and Cox regressions by using 14 covariables that could act as potential confounders. RESULTS: Overall median (IQR) age was 84 (IQR = 77-89) years, and 56% were women. Vaccinated patients (n = 1139; 19%) were older, had more comorbidities and had worse baseline status, as assessed by New York Heart Association class and Barthel index, than did unvaccinated patients (n = 5008; 81%). Infection triggering decompensation was more common in vaccinated patients (50% vs 41%; P < 0.001). In vaccinated and unvaccinated patients, high or very-high risk decompensation was seen in 21.9% and 21.1%; hospitalization occurred in 72.5% and 73.7%; in-hospital mortality was 7.4% and 7.0%; 90-day postdischarge adverse events were 57.4% and 53.2%; and the 90-day mortality rate was 15.8% and 16.6%, respectively, with no significant differences between cohorts. After adjusting, vaccinated decompensated patients with HF had decreased odds for hospitalization (OR = 0.823, 95%CI = 0.709-0.955). CONCLUSION: In patients with HF, seasonal flu vaccination is associated with less severe decompensations.

Ambient temperature and atmospheric pressure at discharge as precipitating factors in immediate adverse events in patients treated for decompensated heart failure.

To investigate the relationship of ambient temperature and atmospheric pressure (AP) at patient discharge after an episode of acute heart failure (AHF) with very early post-discharge adverse outcomes. We analyzed 14,656 patients discharged after an AHF episode from 26 hospitals in 16 Spanish cities. The primary outcome was the 7-day post-discharge combined adverse event (emergency department -ED- revisit or hospitalization due to AHF, or all-cause death), and secondary outcomes were these three adverse events considered individually. Associations (adjusted for patient and demographic conditions, and length of stay -LOS- during the AHF index episode) of temperature and AP with the primary and secondary outcomes were investigated. We used restricted cubic splines to model the continuous non-linear association of temperature and AP with each endpoint. Some sensitivity analyses were performed. Patients were discharged after a median LOS of 5 days (IQR = 1-10). The highest temperature at discharge ranged from - 2 to 41.6 °C, and AP was from 892 to 1037 hPa. The 7-day post-discharge combined event occurred in 1242 patients (8.4%), with percentages of 7-day ED-revisit, hospitalization and death of 7.8%, 5.1% and 0.9%, respectively. We found no association between the maximal temperature and AP on the day of discharge and the primary or secondary outcomes. Similarly, there were no significant associations when the analyses were restricted to hospitalized patients (median LOS = 7 days, IQR = 4-11) during the index event, or when lag-1, lag-2 or the mean of the 3 post-discharge days (instead of point estimation) of ambient temperature and AP were considered. Temperature and AP on the day of patient discharge are not independently associated with the risk of very early adverse events during the vulnerable post-discharge period in patients discharged after an AHF episode.

Anisotropic thermoreflectance thermometry: A contactless frequency-domain thermoreflectance approach to study anisotropic thermal transport.

We developed a novel contactless frequency-domain thermoreflectance approach to study thermal transport, which is particularly convenient when thermally anisotropic materials are considered. The method is based on a line-shaped heater geometry, produced with a holographic diffractive optical element, instead of using a spot heater as in conventional thermoreflectance. The heater geometry is similar to the one used in the 3-omega method, however, keeping all the technical advantages offered by non-contact methodologies. The present method is especially suitable to determine all the elements of the thermal conductivity tensor, which is experimentally achieved by simply rotating the sample with respect to the line-shaped optical heater. We provide the mathematical solution of the heat equation for the cases of anisotropic substrates, thin films, and multilayer systems. This methodology allows an accurate determination of the thermal conductivity and does not require complex modeling or intensive computational efforts to process the experimental data, i.e., the thermal conductivity is obtained through a simple linear fit ("slope method"), in a similar fashion to the 3-omega method. We demonstrate the potential of this approach by studying isotropic and anisotropic materials in a wide range of thermal conductivities. In particular, we have studied the following inorganic and organic systems: (i) glass, Si, and Ge substrates (isotropic), (ii) ß-Ga2O3 and a Kapton substrate (anisotropic), and (iii) a 285 nm thick SiO2 thin film deposited on a Si substrate. The accuracy in the determination of the thermal conductivity is estimated as ≈5%, whereas the temperature uncertainty is ΔT ≈ 3 mK.

Quantifying thermal transport in buried semiconductor nanostructures via cross-sectional scanning thermal microscopy.

Managing thermal transport in nanostructures became a major challenge in the development of active microelectronic, optoelectronic and thermoelectric devices, stalling the famous Moore's law of clock speed increase of microprocessors for more than a decade. To find the solution to this and linked problems, one needs to quantify the ability of these nanostructures to conduct heat with adequate precision, nanoscale resolution, and, essentially, for the internal layers buried in the 3D structure of modern semiconductor devices. Existing thermoreflectance measurements and "hot wire" 3ω methods cannot be effectively used at lateral dimensions of a layer below a micrometre; moreover, they are sensitive mainly to the surface layers of a relatively high thickness of above 100 nm. Scanning thermal microscopy (SThM), while providing the required lateral resolution, provides mainly qualitative data of the layer conductance due to undefined tip-surface and interlayer contact resistances. In this study, we used cross-sectional SThM (xSThM), a new method combining scanning probe microscopy compatible Ar-ion beam exit nano-cross-sectioning (BEXP) and SThM, to quantify thermal conductance in complex multilayer nanostructures and to measure local thermal conductivity of oxide and semiconductor materials, such as SiO2, SiGex and GeSny. By using the new method that provides 10 nm thickness and few tens of nm lateral resolution, we pinpoint crystalline defects in SiGe/GeSn optoelectronic materials by measuring nanoscale thermal transport and quantifying thermal conductivity and interfacial thermal resistance in thin spin-on materials used in extreme ultraviolet lithography (eUV) fabrication processing. The new capability of xSThM demonstrated here for the first time is poised to provide vital insights into thermal transport in advanced nanoscale materials and devices.

Equal Footing of Thermal Expansion and Electron-Phonon Interaction in the Temperature Dependence of Lead Halide Perovskite Band Gaps.

Lead halide perovskites, which are causing a paradigm shift in photovoltaics, exhibit an atypical temperature dependence of the fundamental gap: it decreases in energy with decreasing temperature. Reports ascribe such a behavior to a strong electron-phonon renormalization of the gap, neglecting contributions from thermal expansion. However, high-pressure experiments performed on the archetypal perovskite MAPbI3 (MA stands for methylammonium) yield a negative pressure coefficient for the gap of the tetragonal room-temperature phase, which speaks against the assumption of negligible thermal expansion effects. Here we show that for MAPbI3 the temperature-induced gap renormalization due to electron-phonon interaction can only account for about 40% of the total energy shift, thus implying thermal expansion to be more if not as important as electron-phonon coupling. Furthermore, this result possesses general validity, holding also for the tetragonal or cubic phase, stable at ambient conditions, of most halide perovskite counterparts.

Maternal folic acid supplementation reduces the severity of cleft palate in Tgf-ß3 null mutant mice.

BACKGROUND: Cleft palate (CP) constitutes the most frequently seen orofacial cleft and is often associated with low folate status. Folate plays an essential role in the human body as a major coenzyme in one-carbon metabolism, including DNA synthesis, repair, and methylation. Whether the administration of isolated folic acid (FA) supplements prevents the CP caused by genetic mutations is unknown, as is its effect on the mechanisms leading to palate fusion. METHODS: FA was administered to females from two different strains of transforming growth factor ß3 heterozygous mice. Null mutant progeny of these mice exhibit CP in 100% of cases of varying severity. We measured cleft length, height of palatal shelf adhesion, and the number of proliferating mesenchymal cells. Immunohistochemistry was also carried for collagen IV, laminin, fibronectin, cytokeratin-17, and EGF. RESULTS: FA supplementation significantly reduced CP severity and improved palatal shelf adhesion in both strains both in vivo and in vitro. Medial edge epithelium proliferation increased, and its differentiation was normalized as indicated by the presence and disposition of collagen IV, laminin, fibronectin, and cytokeratin-17. CONCLUSIONS: A maternal FA supplementation reduces the CP appearance by improving the mechanisms leading to palatal shelf adhesion.

Dynamic disorder, phonon lifetimes, and the assignment of modes to the vibrational spectra of methylammonium lead halide perovskites.

We present Raman and terahertz absorbance spectra of methylammonium lead halide single crystals (MAPbX3, X = I, Br, Cl) at temperatures between 80 and 370 K. These results show good agreement with density-functional-theory phonon calculations. Comparison of experimental spectra and calculated vibrational modes enables confident assignment of most of the vibrational features between 50 and 3500 cm-1. Reorientation of the methylammonium cations, unlocked in their cavities at the orthorhombic-to-tetragonal phase transition, plays a key role in shaping the vibrational spectra of the different compounds. Calculations show that these dynamic effects split Raman peaks and create more structure than predicted from the independent harmonic modes. This explains the presence of extra peaks in the experimental spectra that have been a source of confusion in earlier studies. We discuss singular features, in particular the torsional vibration of the C-N axis, which is the only molecular mode that is strongly influenced by the size of the lattice. From analysis of the spectral linewidths, we find that MAPbI3 shows exceptionally short phonon lifetimes, which can be linked to low lattice thermal conductivity. We show that optical rather than acoustic phonon scattering is likely to prevail at room temperature in these materials.

Experimental and theoretical optical properties of methylammonium lead halide perovskites.

The optical constants of methylammonium lead halide single crystals CH3NH3PbX3 (X = I, Br, Cl) are interpreted with high level ab initio calculations using the relativistic quasiparticle self-consistent GW approximation (QSGW). Good agreement between the optical constants derived from QSGW and those obtained from spectroscopic ellipsometry enables the assignment of the spectral features to their respective inter-band transitions. We show that the transition from the highest valence band (VB) to the lowest conduction band (CB) is responsible for almost all the optical response of MAPbI3 between 1.2 and 5.5 eV (with minor contributions from the second highest VB and the second lowest CB). The calculations indicate that the orientation of [CH3NH3](+) cations has a significant influence on the position of the bandgap suggesting that collective orientation of the organic moieties could result in significant local variations of the optical properties. The optical constants and energy band diagram of CH3NH3PbI3 are then used to simulate the contributions from different optical transitions to a typical transient absorption spectrum (TAS).

Embryonic cerebrospinal fluid in brain development: neural progenitor control.

Due to the effort of several research teams across the world, today we have a solid base of knowledge on the liquid contained in the brain cavities, its composition, and biological roles. Although the cerebrospinal fluid (CSF) is among the most relevant parts of the central nervous system from the physiological point of view, it seems that it is not a permanent and stable entity because its composition and biological properties evolve across life. So, we can talk about different CSFs during the vertebrate life span. In this review, we focus on the CSF in an interesting period, early in vertebrate development before the formation of the choroid plexus. This specific entity is called "embryonic CSF." Based on the structure of the compartment, CSF composition, origin and circulation, and its interaction with neuroepithelial precursor cells (the target cells) we can conclude that embryonic CSF is different from the CSF in later developmental stages and from the adult CSF. This article presents arguments that support the singularity of the embryonic CSF, mainly focusing on its influence on neural precursor behavior during development and in adult life.

Poly(3-hexylthiophene) nanowires in porous alumina: internal structure under confinement.

We study the structure of poly(3-hexylthiophene) (P3HT) subjected to nanoscale confinement in two dimensions (2D) as imposed by the rigid walls of nanopore anodic aluminum oxide (AAO) templates. P3HT nanowires with aspect ratios (length-to-diameter) above 1000 and diameters ranging between 15 nm and 350 nm are produced in the pores of the AAO templates via two processing routes. These are, namely, drying a solution or cooling from the melt. Our study focuses on the effects of nanoconfinement on the semicrystalline nature of the nanowires, the orientation of crystals, and the evolution of the structures that P3HT might develop under confinement, which we investigate by combining imaging (SEM), spectroscopic (FTIR, photoluminescence) and structural characterization (WAXS, DSC) techniques. Solution-processed P3HT nanowires are essentially amorphous and porous, whereas melt-processed nanowires are semicrystalline, and present a more compact morphology and smoother surfaces. In the latter case, the orientation of crystals was found to strongly depend on the pore diameter. In large diameter nanowires (250 nm and 120 nm), crystals are oriented laying the π-π stacking direction parallel to the nanowire axis. In contrast, in small diameter nanowires, the π-π stacking direction is mainly perpendicular to the nanowires, as crystals are likely to nucleate at pore walls. The structural evolution of P3HT upon heating into weakly (250 nm in diameter) and strongly (15 nm in diameter) confining pores has been studied. A complex set of structures is observed, i.e., crystals, a solid layered mesophase, a nematic/smectic mesophase, and the isotropic melt. Interestingly, a rare crystal polymorph (form II) is also observed under strong confinement conditions together with the usual lamellar crystal form I. Furthermore, we show that nanoconfinement stabilizes form II: such crystals are still present at 210 °C while in the bulk they get converted to form I crystals at around 50 °C.

Effect of structure and interlayer diffusion in organic position sensitive photodetectors based on complementary wedge donor/acceptor layers.

We have developed organic photodetectors based on two complementary wedge layers made of CuPc and C60 and observed a strong spatial dependence of the spectral response on the position of the incident light spot. Photocurrent measurements are correlated with atomic force microscopy (AFM), micro-Raman and ellipsometry maps in order to provide insights into the local donor/acceptor concentration, layer thickness and nature of the donor-acceptor interface along the direction of the thickness gradient. Deviations in spatial dependence between experimental photocurrent values and those predicted with a model assuming a sharp and well defined organic-organic interface are discussed in terms of inter-diffusion layers.

Caracterización: fenotípica de varones adultos condiagnóstico de síndrome X frágil / Phenotypic characterization of adult men diagnosed with fragile X syndrome

El síndrome X frágil (SXF), constituye la primera causa de discapacidad intelectualhereditaria. Es una de las alteraciones más frecuentes aunque no siempre bien conocidapor los profesionales de la salud, los educadores y la sociedad. El desconocimiento provocaque un porcentaje importante de afectados esté sin diagnosticar. Hay importantes diferenciasentre comunidades autónomas, en algunas, el síndrome esta infradiagnosticado,no llevándose a cabo la detección, el consejo genético ni la adecuada intervención educativa.Tras revisar las características generales del SXF, presentamos el estudio realizado enla provincia de Burgos, recogiéndose datos de 273 varones con discapacidad intelectual,57 fueron estudiados genéticamente resultando 13 nuevos afectados.Al menos, el 9,5% de varones atendidos en los centros de discapacidad intelectual en laprovincia de Burgos, no diagnosticados por síndromes o discapacidades excluyentes,están afectados de SXF.La hoja de recogida de datos (HRD-1), seleccionó los participantes a estudiar genéticamentey con las modificaciones se ha obtenido la HRD-2, que consideramos sirve comoprotocolo facilitador para la preselección de posibles varones adultos afectados (AU)

Fragile X syndrome (FXS) is the first known cause of hereditary intellectual disability.Although one of the most common alterations, it is not always well known by health professionals,educators and society in general. This lack of knowledge means that a significantpercentage of those affected are not diagnosed. Major differences among autonomouscommunities exist; in some of them, the syndrome is under diagnosed, due to non-detection,lack of genetic counselling or adequate educational intervention. After reviewing thegeneral characteristics of FXS, we hereby present the study conducted in the province ofBurgos, where data was gathered from 273 males with intellectual disability. 57 of themwere genetically studied, resulting in the detection of 13 new cases of FXS. The data collectionsheet (HRD-1) was the basis for selecting the participants to be studied; this, afterundergoing the necessary modifications, resulted in HRD-2. We believe that this sheet canbe used as a protocol to facilitate the pre-selection of possible affected adult males.At least 9.5% of males treated at the centres for the intellectually disabled in theprovince of Burgos, who have not been diagnosed with syndromes or exclusive disabilities,suffer from FXS (AU)

Valor diagnóstico de la ecografía Doppler color en el control clínico de la reparación endovascular de los aneurismas de aorta abdominal / The diagnostic value of colour Doppler ultrasonography in the clinical monitoring of endovascular abdominal aortic aneurysm repair

Introducción. El control clínico del tratamiento endovascular de la enfermedad aneurismática de la aorta abdominal se basa en la valoración de la evolución del tamaño del aneurisma, la permeabilidad de la endoprótesis y la detección de fugas. Objetivo. Comparar la ecografía Doppler (ED) color con la tomografía axial computarizada (TAC) en la evaluación del tamaño del aneurisma y la detección de fugas en el tratamiento endovascular de aneurismas de aorta abdominal. Pacientes y métodos. Estudio prospectivo entre enero y diciembre de 2005. En 14 pacientes sometidos a tratamiento endovascular se realizó ED color y TAC a 1, 6 y 12 meses. Se compararon los tamaños del aneurisma mediante la prueba t para muestras dependientes y estudio de correlación. Sensibilidad, especificidad, valor predictivo positivo y valor predictivo negativo y el coeficiente de concordancia kappa se calcularon para la detección de fugas. Resultados. El control clínico medio fue de 9,4 meses y se compararon 49 exploraciones. El diámetro medio del aneurisma a los tres meses de control clínico fue de 51,2 cm con ED color y de 52,5 cm con TAC (p = no significativo). El coeficiente de correlación ascendió a 0,97 (p < 0,001). Todos los dispositivos se mantuvieron permeables. En detección de fugas, el estudio ED color obtuvo una sensibilidad, especificidad, valor predictivo positivo y valor predictivo negativo de 75, 61, 20 y 95%, respectivamente (kappa = 0,61). Conclusiones. El estudio ED color obtiene una excelente correlación con la TAC en la medida del tamaño de los aneurismas. En cambio, posee un valor predictivo positivo muy bajo para la detección de fugas

Introduction. Clinical monitoring of the endovascular treatment of aneurysmal disease of the abdominal aorta is based on evaluating the progression of the size of the aneurysm, the patency of the stent and the detection of leaks. Aim. To compare colour Doppler ultrasonography (DU) with computerised axial tomography (CAT) for evaluating the size of the aneurysm and the detection of leaks in the endovascular treatment of abdominal aortic aneurysms. Patients and methods. A prospective study between January and December 2005; colour DU and CAT scans were conducted in 14 patients submitted to endovascular treatment at 1, 6 and 12 months. Sizes of the aneurysms were compared by means of the t test for dependent samples and correlation studies. Sensitivity, specificity, predictive positive value and predictive negative value and the kappa coefficient of agreement were calculated for leak detection. Results. The mean period of clinical monitoring was 9.4 months and 49 examinations were compared. The mean diameter of the aneurysm at three months’ clinical monitoring was 51.2 cm with colour DU and 52.5 cm with CAT scanning (p = non-significant). The correlation coefficient was 0.97 (p < 0.001). Patency was maintained in all the devices. In the detection of leaks, the results of the colour DU study for sensitivity, specificity, predictive positive value and predictive negative value were 75, 61, 20 and 95%, respectively (kappa = 0.61). Conclusions. The colour DU study correlates very well with CAT in the measurement of the size of aneurysms. In contrast, it has a very low predictive positive value for the detection of leaks

Efecto de la trombosis carotídea en el comportamiento hemodinámico de la estenosis contralateral: criterios para su determinación / The effect of carotid thrombosis on the haemodynamic behaviour of contralateral stenosis: criteria for its determination

Objetivo. Comparar la precisión diagnóstica de varios parámetros hemodinámicos en la graduación de la estenosis carotídea en pacientes con oclusión contralateral. Pacientes y métodos. Se diseñó un estudio prospectivo de 76 pacientes con oclusión carotídea unilateral, en el que se correlacionaron de manera ciega los hallazgos de eco- Doppler color y arteriografía. Cada carótida se clasificó, según el grado estenótico angiográfico, en: 1-29% (n = 39), 30-49% (n = 15), 50-69% (n = 14), >= 70% (n = 8). Se consideraron cinco criterios hemodinámicos para valorar una estenosis > 50%: Universidad de Washington (estándar); AbuRahma (pico de velocidad sistólica, PSV > 140 cm/s; velocidad diastólica final, EDV 140 cm/s; EDV 1,5; y método nuevo (ratio de la ICA/CCA > 1,3; PSV > 115 cm/s). Se calcularon la sensibilidad, la especificidad, los valores predictivos positivo y negativo, el valor diagnóstico y el índice de concordancia κ. Resultados. La mejor concordancia arteriografía/eco-Doppler se dio para el método nuevo (κ = 0,59), con una precisión diagnóstica del 84,2, seguida del método estándar (que obtuvo una κ = 0,53 y una precisión de 82,8). Los métodos específicos para pacientes con trombosis carotídea unilateral (AbuRahma y Fujitani) fueron los menos eficaces, mientras que el método de la ratio presentó resultados intermedios. Conclusiones. La presencia de oclusión produce una sobreestimación o infraestimación del grado estenótico ipsilateral según los criterios clásicos admitidos. Este problema puede reducirse mediante la utilización de una ratio > 1,3 y un PSV > 115 cm/s. Para evaluar el grado de progresión de la enfermedad carotídea cada laboratorio ha de validar sus propios criterios, los cuales deben permitir diferenciar entre lesiones hemodinámicamente significativas y aquellas que no lo son (AU)

Aim. To compare the accuracy of various duplex hemodynamic criteria in grading ipsilateral carotid stenosis in patients with contralateral occlusion. Patients and methods. A prospective study was designed with 76 patients who had unilateral carotid occlusion, the results of duplex were correlated in blind fashion to arteriography. Each carotid was classified in order to the angiographic stenotic grade in: 1-29% (n = 39), 30-49% (n = 15), 50-69% (n = 14), ≥ 70% (n = 8). Five duplex ultrasonography classification criteria for discriminate > 50% stenosis were used: Washington University (standard), AbuRahma (peak systolic velocity, PSV > 140 cm/s; diastolic velocity, EDV 140 cm/s; EDV 1.5; new method (ratio ICA/ CCA > 1.3; PSV > 115 cm/s). The sensibility, specificity, positive predictive value, negative predictive value, accuracy and κ index were calculated. Results. Best concordance between angiography and duplex was for the new method, providing a κ = 0.59 and an accuracy of 84.2, followed by standard method that obtained κ = 0.53 and an accuracy of 82.8. Specific methods for patients with unilateral occlusion of ICA (AbuRahma and Fujitani) provided inferior efficacy in detecting carotid stenosis >= 50%, although the ratio method obtained intermediate results. Conclusions. The fact of having a contralateral occlusion of the ICA produces some overestimation or underestimation of the ipsilatral carotid stenosis degree following the classic criteria. This problem can be reduced using a ratio > 1.3 and a PSV > 115 cm/s. Each laboratory should perform an objective evaluation of their own criteria of diagnosis to discriminate hemodynamically significant lesions (AU)

Transposición de la arteria vertebral (segmento V1) al tronco tirocervical / Transposition of the vertebral artery (segment V1) to the thyrocervical trunk

Describimos una técnica de reconstrucción de la arteria vertebral en su segmento proximal. Realizamos transposición de la arteria vertebral al tronco tirocervical; tras ligar sus ramas, aprovechamos el muñón para realizar la anastomosis. Pacientes y métodos. Revisamos retrospectivamente nuestra experiencia, desde 1992 hasta 2001. Realizamos dicha reconstrucción a cinco pacientes varones, con sintomatología vertebrobasilar, con edad media 64 años y patología en carótida común o interna ipsilateral o carótida interna contralateral. Técnica quirúrgica: en un primer tiempo se llevó a cabo la intervención sobre la carótida interna contralateral (n= 3). Al mes, realizamos un abordaje medial al esternocleidomastoideo, mediante incisión oblicua supraclavicular; al disecar entre carótida común y yugular interna vemos nervio vago, conducto torácico y vena vertebral que ligamos, observando la arteria vertebral. Seccionamos la arteria vertebral por debajo de la lesión. Hemos de tener sumo cuidado con la cadena simpática cervical, nervio vertebral y ganglio simpático cervical inferior. Lateralmente al origen de la vertebral nace el tronco tirocervical, ligamos sus ramas y sobre el muñón realizamos la anastomosis de la arteria vertebral mediante pinzamiento subclavio parcial. Resultados. Se realizaron cinco transposiciones, un paciente sufrió un accidente isquémico transitorio en el postoperatorio inmediato, con recuperación sin secuelas. Durante el seguimiento se observó, mediante ecografía Doppler, permeabilidad del 100 por ciento, y sólo un paciente falleció al tercer año por cardiopatía isquémica. Conclusión. Creemos que la transposición del segmento proximal de la arteria vertebral al tronco tirocervical es una maniobra quirúrgica poco agresiva, sin pinzamientos de troncos principales, que acorta el acto quirúrgico y tiene baja morbimortalidad (AU)