Entangled States Induced by Electron-Phonon Interaction in Two-Dimensional Materials.

We report on the effects of electron-phonon interaction in materials such as graphene, showing that it enables the formation of a gap bridged by unique edge states. These states exhibit a distinctive locking among propagation direction, valley, and phonon mode, allowing for the generation of electron-phonon entangled states whose parts can be easily split. We discuss the effect of the chiral atomic motion in the zone boundary phonons leading to this effect. Our findings shed light on how to harness these unconventional states in quantum research.

Inducing a topological transition in graphene nanoribbon superlattices by external strain.

Armchair graphene nanoribbons, when forming a superlattice, can be classified into different topological phases, with or without edge states. By means of tight-binding and classical molecular dynamics (MD) simulations, we studied the electronic and mechanical properties of some of these superlattices. MD shows that fracture in modulated superlattices is brittle, as for unmodulated ribbons, and occurs at the thinner regions, with staggered superlattices achieving a larger fracture strain than inline superlattices. We found a general mechanism to induce a topological transition with strain, related to the electronic properties of each segment of the superlattice, and by studying the sublattice polarization we were able to characterize the transition and the response of these states to the strain. For the cases studied in detail here, the topological transition occurred at ∼3-5% strain, well below the fracture strain. The topological states of the superlattice - if present - are robust to strain even close to fracture. The topological transition was characterized by means of the sublattice polarization of the states.

Efficacy and tolerability of a low-residue diet for bowel preparation: systematic review and meta-analysis.

BACKGROUND: Colorectal cancer (CRC) contributes significantly to cancer mortality worldwide. In an effort to reduce the risk of death, detection of polyps through colonoscopy is crucial. The success of the colonoscopy depends on the diet administered the day before the test. Our aim was to evaluate the efficacy, tolerability, and adverse effects of bowel preparation when using a low-residual diet (LRD) compared to a clear-liquid diet (CLD) the day before a scheduled colonoscopy. METHODS: PubMed/Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL) and Scopus databases were searched. We included studies of patients undergoing a scheduled colonoscopy for CRC screening and surveillance or for diagnostic purposes that compared a LRD with a CLD the day before the colonoscopy. Efficacy, the primary outcome, was evaluated as the rate of adequate bowel preparation. Secondary outcomes were tolerability and adverse effects of bowel preparation. RESULTS: Thirteen RCTs (N = 2587) were included. Patients receiving a LRD compared to a CLD showed no difference in adequate bowel preparations (RR 1.02; 95% CI 0.99-1.05; I2 = 60%). However, the LRD improved patient tolerability (RR 1.17; 95% CI 1.12-1.23; I2 = 66%) and had fewer adverse effects (RR 0.89; 95% CI 0.84-0.94; I2 = 73%) compared to the CLD. Groups using a LRD with 4L of polyethylene glycol in a single dose or a LRD with < 2000 kcal < 32 g of fibres/day had better tolerability. CONCLUSION: Based on these findings, our recommendation is strong in favour of a LRD for bowel preparation of patients undergoing a scheduled colonoscopy. This diet could also be useful as a preoperative colonic preparation, but this requires further research.

Ecoendoscopia en la estadificación del cáncer de esófago y de estómago / Endoscopic ultrasound for staging of esophageal and gastric cancers

RESUMEN Antecedentes: tanto el adenocarcinoma gástrico (ACG) como el esofágico (ACE) son una de las princi pales causas de muerte por cáncer digestivo en el mundo, si bien la ecoendoscopia (EUS) ha demos trado ser una herramienta valiosa en la estadificación preoperatoria del ACG y ACE en casos seleccio nados. Objetivo: evaluar la utilidad de la EUS en la estadificación de ACG y ACE para seleccionar los pacientes candidatos a neoadyuvancia, comparándola con la etapa previa a la implementación de la EUS en un centro quirúrgico de la Argentina. Material y métodos: se incluyó una serie consecutiva de pacientes con ACE y ACG durante el período 2013- 2019. Se excluyeron pacientes con criterios de irresecabilidad y operados de urgencia. Se dividió la muestra en cuatro grupos: G1 y G2 ACE con y sin EUS, G3 y G4 ACG con y sin EUS, respectivamente. Se evaluaron variables clínicas, anatomopatológicas y de supervivencia en todos los grupos. Resultados: se incluyó un total de 89 pacientes, de los cuales 40 fueron por ACE, 30 pacientes perte necieron a G1 vs. 10 a G2. Se analizaron 49 pacientes con ACG, 20 pertenecieron a G3, mientras que 29 a G4. En los pacientes estadificados con EUS, en G1, 23 pacientes realizaron neoadyuvancia (76 %) versus 2 pacientes en G2 (20 %) p: ≤ 0,005. En G3 realizaron quimioterapia perioperatoria 8 pacientes (40 %), mientras que en G4, solo dos pacientes (7 %) p: ≤ 0,005. En cuanto al análisis de metástasis ganglionares (G+) en la anatomía patológica, tuvimos un aumento esperable en los pacientes no esta dificados con EUS en cáncer esofágico donde, en G1, el 30% tuvieron G+ versus 60% en G2 p: ≤ 0,005. En G3 y G4 se observó un 45 % de G+. Con un tiempo promedio de seguimiento de 36 meses (6-72), si bien no observamos una diferencia significativa en cuanto a supervivencia global ni recurrencia, observamos una tendencia a favor de los pacientes estadificados con EUS. Conclusión: la utilización de la EUS en la estadificación preoperatoria de ACG y ACE es importante. Aunque su uso puede ser un desafío en muchos centros de la Argentina, futuros esfuerzos son necesa rios para incluir) este estudio en casos seleccionados en la estadificación de tales pacientes.

ABSTRACT Background: Gastric adenocarcinoma (GAC) and esophageal adenocarcinoma (EAC) are one of the leading causes of mortality from gastrointestinal cancer worldwide. Endoscopic ultrasound (EUS) has proved to be a valuable tool for preoperative staging of GAC and EAC in selected cases. Objective: The aim of this study was to evaluate the usefulness of EUS for staging of EAC and GAC and selecting patients who are candidates for neoadjuvant therapy, as compared with the previous stage before the implementation of EUS, in a surgical center in Argentina. Material and methods: Consecutive patients with EAC and GAC between 2013-2019 were included. Patients with criteria of unresectable cancer or who underwent emergency surgery were excluded. The sample was divided into four groups G1 and G2 (EAC with and without EUS, respectively) and G3 and G4 (GAC with and without EUS, respectively). The clinical and anatomopathological variables and survival were evaluated in all the groups. Results: A total of 89 patients were included, 40 with EAC (30 in G1 and 10 in G2, and 49 with GAC, 20 in G3 and 29 in G4. Of the patients undergoing EUS staging in G1, 23 (75%) received neoadjuvant therapy vs. 2 patients in G2 (20%) (P ≤ 0.005). Eight patients (40%) in G3 and 2 (7%) in G4 received perioperative chemotherapy (P ≤ 0.005). Lymph node metastases were observed in 9 (30%) of surgical specimens of EAC in G1 and in 60% in G2 (P ≤ 0.005), and in 45% in G3 and G4. After a mean follow-up of 36 months (6-72), we observed a non-significant trend toward higher overall survival and disease-free survival in patients undergoing EUS staging. Conclusion: EUS for preoperative staging pf EAC and GAC is a useful tool. Although the use of EUS use may be a challenging task in many centers in Argentina, future efforts are needed to include this test in selected cases for staging patients with these types of cancers.

Estudio prospectivo acerca de la precisión diagnóstica del test inmunológico de sangre oculta en materia fecal en una única ronda para la realización de pesquisa del cáncer colorrectal en pacientes de riesgo promedio en la Argentina / Prospective study on the diagnostic accuracy of the immunochemical fecal occult blood test in a single round for colorectal cancer screening in average risk patients in Argentina

Introducción: El cáncer colorrectal (CCR) es la segunda causa de muerte por cáncer en Argentina. Debido a su alta prevalencia es fundamental normatizar un programa de pesquisa para la prevención y detección temprana. La precisión del test de sangre oculta en materia fecal inmunológico (SOMFi) para pesquisa de CCR en población de riesgo promedio ha demostrado ser adecuada según la bibliografía internacional, no habiendo, sin embargo, información a nivel local. El objetivo es evaluar en nuestro medio la precisión diagnóstica del test de SOMFi en una única ronda para la pesquisa de CCR en pacientes de riesgo promedio. Diseño: Prospectivo de precisión diagnóstica. Material y Método: Se incluyeron pacientes con riesgo promedio que consultaron para realizar una videocolonoscopía (VCC) por pesquisa de CCR en el Hospital Alemán de Buenos Aires, entre el 1 de junio del 2015 y 31 diciembre de 2017. Se excluyeron todos los pacientes con riesgo incrementado para CCR. Todos los pacientes realizaron el test de SOMFi y posteriormente la VCC. Los endoscopistas estaban ciegos para el resultado del test al momento de realizar la VCC. Se evaluó la precisión diagnóstica del test SOMFi para detectar lesiones neoplásicas avanzadas (LNA) calculando la sensibilidad (S), especificidad (E), valor predictivo positivo (VVP) y negativo (VVN), coeficiente de probabilidad positivo (CP+) y negativo (CP-). Se evaluó también la precisión para la detección de adenomas de bajo riesgo, pólipos aserrados y CCR. Resultados: Se incluyeron un total de 300 pacientes; 273 (91%) entregaron la muestra de materia fecal para realizar el test de SOMFi y completaron la VCC. La edad media de los pacientes fue de 56.9 (40-85) años y 54% fueron hombres. Del total de pacientes que realizaron ambos estudios (273), 53 pacientes (19%) presentaron al menos un adenoma de bajo riesgo, en 18 pacientes (6,59%) observamos al menos un adenoma aserrado sésil y en 21 pacientes (7,7%) al menos una lesión neoplásica avanzada (LNA). Solo 4 pacientes (1.5%) presentaron CCR. En cuanto a la precisión diagnóstica del test de SOMFi en una única ronda para detectar LNA observamos una S de 30%, E de 84%, VPP de 13% y un VPN de 94%. Para adenomas de bajo riesgo observamos una S de 13%, E de 84%, VPP de 17%, VPN de 79%. Para adenomas aserrados sésiles observamos una S de 16.7%, E de 87%, VPP de 11% y de VPN 91%. La precisión para el CCR fue la siguiente, S de 75%, E de 83%, VPP 6%, VPN 99%. No se observaron complicaciones post procedimientos. Conclusiones: La precisión diagnóstica del test de SOMFi en nuestro medio es comparable a los resultados internacionales. Sin embargo, la baja precisión observada en una única ronda realza la necesidad de realizarlo de forma anual o bianual para poder optimizar su precisión y lograr programas de pesquisa efectivos.(AU)

Background: Colorectal cancer (CRC) is the second leading cause of cancer death in Argentina. Due to its high prevalence, it is essential to standardize a screening program for prevention and early detection. According to international literature, the accuracy of the immunochemical fecal occult blood test (FIT) for CRC screening in an average-risk population has proven to be adequate, but there is no information at the local level. Objective: To evaluate the diagnostic accuracy of the FIT test in a single round for CRC screening in average-risk patients in our setting. Design: Diagnostic accuracy prospective study. Material and Methods: Average-risk patients who consulted for a CRC screening video colonoscopy (VCC) at the Hospital Alemán of Buenos Aires, between June 1, 2015 and December 31, 2017 were included. All patients with increased risk for CRC were excluded. All patients performed FIT and subsequently VCC. The endoscopists were blind to FIT result at the time of VCC. The diagnostic accuracy of FIT to detect advanced neoplastic lesions (ANL) was evaluated by calculating sensitivity (S), specificity (Sp), positive predictive value (PPV), negative (NPV), positive likelihood ratio (LR+) and negative likelihood ratio (LR-). The accuracy for the detection of low-risk adenomas, serrated polyps and CRC was also evaluated. Results: A total of 300 patients were included; 273 (91%) submitted the stool sample to perform FIT and completed VCC. The mean age of patients was 56.9 (40-85) years and 54% were men. Of the total number of patients who carried out both studies (273), 53 (19%) patients had at least one low-risk adenoma, 18 (6.59%) patients had at least one sessile serrated adenoma and 21 (7.7%) patients had at least one ANL. Only 4 (1.5%) patients presented CRC. The diagnostic accuracy of FIT in a single round to detect ANL was: S 30%, Sp 84%, PPV 13%, NPV 94%; for low-risk adenomas: S 13%, Sp 84%, PPV 17%, NPV 79%; for sessile serrated adenomas: S 16.7%, Sp 87%, PPV 11%, NPV 91% and for CRC: S 75%, Sp 83%, PPV 6%, NPV 99%. No post-procedure complications were observed. Conclusions: The diagnostic accuracy of FIT in our setting is comparable to international results. However, the low precision observed in a single round highlights the need to do it annually or biannually in order to optimize its accuracy and achieve effective screening programs. (AU)

[Lung cancer diagnosed by transesophageal ecoendoscopy and fine needle aspiration biopsy]. / Cáncer de pulmón diagnosticado mediante ecoendoscopía transesofágica y biopsia por punción con aguja fina.

Lung cancer is one of the leading causes of death worldwide. Pulmonary nodules located in the vicinity of the mediastinum, retrocardiac, near the aorta or pulmonary vessels, and in front of the spine, may be difficult to access through a percutaneous or bronchoscopic approach. Fine needle aspiration/biopsy guided by transesophageal echoendoscopy (EUS-FNA/FNB) is a minimally invasive method with low morbidity that could allow access to lesions in these places. We present the case of a patient with a solitary pulmonary nodule, in which the diagnosis of lung cancer was obtained by EUS-FNA/FNB.

El cáncer de pulmón es la principal causa de muerte por cáncer en todo el mundo. Los nódulos pulmonares ubicados en proximidad al mediastino, retrocardíacos, cercanos a grandes vasos o por delante de la columna vertebral pueden resultar de difícil acceso por vía percutánea o broncoscópica. La punción aspiración/biopsia con aguja fina guiada por ecoendoscopía transesofágica (EUS-FNA/FNB) es un método mini invasivo con baja morbilidad que permitiría acceder a estas localizaciones. Presentamos el caso de un paciente con nódulo pulmonar solitario, en el que se obtuvo el diagnóstico de cáncer de pulmón mediante EUS-FNA/FNB.

Cáncer de pulmón diagnosticado mediante ecoendoscopia transesofágica y biopsia por punción con aguja fina / Lung cancer diagnosed by transesophageal ecoendoscopy and fine needle aspiration biopsy

El cáncer de pulmón es la principal causa de muerte por cáncer en todo el mundo. Los nódulos pulmonares ubicados en proximidad al mediastino, retrocardíacos, cercanos a grandes vasos o por delante de la columna vertebral pueden resultar de difícil acceso por vía percutánea o broncoscópica. La punción aspiración/biopsia con aguja fina guiada por ecoendoscopía transesofágica (EUS-FNA/FNB) es un método mini invasivo con baja morbilidad que permitiría acceder a estas localizaciones. Presentamos el caso de un paciente con nódulo pulmonar solitario, en el que se obtuvo el diagnóstico de cáncer de pulmón mediante EUS-FNA/FNB.

Lung cancer is one of the leading causes of death worldwide. Pulmonary nodules located in the vicinity of the mediastinum, retrocardiac, near the aorta or pulmonary vessels, and in front of the spine, may be difficult to access through a percutaneous or bronchoscopic approach. Fine needle aspiration/biopsy guided by transesophageal echoendoscopy (EUS-FNA/FNB) is a minimally invasive method with low morbidity that could allow access to lesions in these places. We present the case of a patient with a solitary pulmonary nodule, in which the diagnosis of lung cancer was obtained by EUS-FNA/FNB.

Gastrointestinal bleeding prophylaxis for critically ill patients: a clinical practice guideline.

CLINICAL QUESTION: What is the role of gastrointestinal bleeding prophylaxis (stress ulcer prophylaxis) in critically ill patients? This guideline was prompted by the publication of a new large randomised controlled trial. CURRENT PRACTICE: Gastric acid suppression with proton pump inhibitors (PPIs) or histamine-2 receptor antagonists (H2RAs) is commonly done to prevent gastrointestinal bleeding in critically ill patients. Existing guidelines vary in their recommendations of which population to treat and which agent to use. RECOMMENDATIONS: This guideline panel makes a weak recommendation for using gastrointestinal bleeding prophylaxis in critically ill patients at high risk (>4%) of clinically important gastrointestinal bleeding, and a weak recommendation for not using prophylaxis in patients at lower risk of clinically important bleeding (≤4%). The panel identified risk categories based on evidence, with variable certainty regarding risk factors. The panel suggests using a PPI rather than a H2RA (weak recommendation) and recommends against using sucralfate (strong recommendation). HOW THIS GUIDELINE WAS CREATED: A guideline panel including patients, clinicians, and methodologists produced these recommendations using standards for trustworthy guidelines and the GRADE approach. The recommendations are based on a linked systematic review and network meta-analysis. A weak recommendation means that both options are reasonable. THE EVIDENCE: The linked systematic review and network meta-analysis estimated the benefit and harm of these medications in 12 660 critically ill patients in 72 trials. Both PPIs and H2RAs reduce the risk of clinically important bleeding. The effect is larger in patients at higher bleeding risk (those with a coagulopathy, chronic liver disease, or receiving mechanical ventilation but not enteral nutrition or two or more of mechanical ventilation with enteral nutrition, acute kidney injury, sepsis, and shock) (moderate certainty). PPIs and H2RAs might increase the risk of pneumonia (low certainty). They probably do not have an effect on mortality (moderate certainty), length of hospital stay, or any other important outcomes. PPIs probably reduce the risk of bleeding more than H2RAs (moderate certainty). UNDERSTANDING THE RECOMMENDATION: In most critically ill patients, the reduction in clinically important gastrointestinal bleeding from gastric acid suppressants is closely balanced with the possibility of pneumonia. Clinicians should consider individual patient values, risk of bleeding, and other factors such as medication availability when deciding whether to use gastrointestinal bleeding prophylaxis. Visual overviews provide the relative and absolute benefits and harms of the options in multilayered evidence summaries and decision aids available on MAGICapp.

A chemical theory of topological insulators.

Research on topological insulators (TIs) has experienced an exponential growth in the last few years, promising new technological applications in fields ranging from electronics to quantum computing. However, the strong condensed matter physical background that is needed to understand the exotic electronic structure of TIs has precluded its dissemination into the chemistry community. In this work we use chemistry-like models (e.g. the Hückel model) to bridge this gap. By taking bond alternating polyacetylenes as a starting point, we show how several key concepts about TIs, such as chiral symmetries or topologically-protected edge states, may be rephrased in terms of traditional chemical concepts by using Lewis resonance structures and bonding descriptors that characterize electron delocalization in real space. Overall, this Highlight should provide the background for understanding the properties of topological insulators to a broad chemistry readership.

Experts' responses in script concordance tests: a response process validity investigation.

CONTEXT: The script concordance test (SCT), designed to measure clinical reasoning in complex cases, has recently been the subject of several critical research studies. Amongst other issues, response process validity evidence remains lacking. We explored the response processes of experts on an SCT scoring panel to better understand their seemingly divergent beliefs about how new clinical data alter the suitability of proposed actions within simulated patient cases. METHODS: A total of 10 Argentine gastroenterologists who served as the expert panel on an existing SCT re-answered 15 cases 9 months after their original panel participation. They then answered questions probing their reasoning and reactions to other experts' perspectives. RESULTS: The experts sometimes noted they would not ordinarily consider the actions proposed for the cases at all (30/150 instances [20%]) or would collect additional data first (54/150 instances [36%]). Even when groups of experts agreed about how new clinical data in a case affected the suitability of a proposed action, there was often disagreement (118/133 instances [89%]) about the suitability of the proposed action before the new clinical data had been introduced. Experts reported confidence in their responses, but showed limited consistency with the responses they had given 9 months earlier (linear weighted kappa = 0.33). Qualitative analyses showed nuanced and complex reasons behind experts' responses, revealing, for example, that experts often considered the unique affordances and constraints of their varying local practice environments when responding. Experts generally found other experts' alternative responses moderately compelling (mean ± standard deviation 2.93 ± 0.80 on a 5-point scale, where 3 = moderately compelling). Experts switched their own preferred responses after seeing others' reasoning in 30 of 150 (20%) instances. CONCLUSIONS: Expert response processes were not consistent with the classical interpretation and use of SCT scores. However, several fruitful and justifiable alternatives for the use of SCT-like methods are proposed, such as to guide assessments for learning.

Prevalence of incidental clinically relevant pancreatic cysts at diagnosis based on current guidelines / Prevalencia de quistes pancreáticos incidentales clínicamente relevantes al momento del diagnóstico basada en las guías actuales

BACKGROUND: Most pancreatic cysts (PCs) found incidentally by CT and MRI scans might not be clinically important according to the Fukuoka guidelines, the American Gastroenterological Association (AGA) guidelines and European guidelines. AIMS: To determine and compare the prevalence of incidental clinically important PCs (CIPCs). METHODS: Abdominal contrast-enhanced CT or MRI scans performed during a one-year period were retrospectively reviewed to identify incidental PCs. CIPCs were defined as those cysts that would be capable of triggering further evaluation with endoscopic ultrasound, immediate surveillance (within 3-6 months) and/or surgery. Prevalence was calculated as the number of patients with CIPCs per 100 subjects imaged (%). RESULTS: Sixty patients (mean age 70 ± 14 years) out of 565 were found to have incidental PCs, representing a prevalence of 8.7% (95% CI 6.3-11.5) in CT scans and 27.5% (95% CI 16-41) in MRI scans. Seven patients (11.6%, 95% CI 5-22) had CIPCs based on size ≥ 30 mm (n = 5), size ≥ 30 mm and pancreatic duct (PD) dilation (n = 1) and PD dilation and presence of solid component (n = 1). Based on the Fukuoka guidelines, the prevalence of CIPCs was 1.2% (95% CI 0.4-2.5) in CT scans (6/507) and 1.7% (95% CI 0.1-9) in MRI scans (1/58). Based on the AGA and European guidelines, the prevalence of CIPCs was 0.2% (95% CI 0.1-1) in CT scans (1/507) and 1.7% (95% CI 0.1-9) in MRI scans (1/58). Patients with PCs initially classified as "AGA- or European-positive" had a higher surgical probability and this decision was taken earlier in the follow-up. CONCLUSIONS: In our cohort, the prevalence of important incidental pancreatic cysts was not negligible at around 1% according to current guidelines

ANTECEDENTES: La mayoría de los quistes de páncreas (PC) hallados incidentalmente en las tomografías (TC) y las resonancias magnéticas (RMN) podrían no ser clínicamente importantes de acuerdo con las actuales guías Fukuoka, American Gastroenterological Association (AGA) y europea. OBJETIVOS: Determinar y comparar la prevalencia de PC incidentales clínicamente importantes (CIPCs). MÉTODOS: Se revisaron retrospectivamente las TC de abdomen con contraste y las RMN durante un período de un año para identificar PCs incidentales. Los CIPC se definieron como aquellos quistes que serían capaces de desencadenar una evaluación ulterior con ecoendoscopia, vigilancia en un corto intervalo (3-6 meses) y/o cirugía. La prevalencia se calculó como el número de pacientes con CIPC por cada 100 sujetos estudiados (%). RESULTADOS: Se encontró que 60 (edad media 70 ± 14 años) de 565 pacientes tenían PC incidentales, lo que representó una prevalencia de 8,7% (IC95% 6,3-11,5) en las TC y 27,5% (IC95% 16-41) en las RMN. Siete pacientes (11,6%, IC 95% 5-22) tenían CIPC basados en el tamaño ≥ 30 mm (n = 5), tamaño ≥ 30 mm y dilatación del conducto pancreático (PD) (n = 1), y dilatación de PD y presencia de componente sólido (n = 1). Basándonos en la guía Fukuoka, la prevalencia de CIPC fue de 1,2% (IC95% 0,4-2,5) en las TC (6/507) y 1,7% (IC95% 0,1-9) en las RMN (1/58). Basado en las guías AGA y europea, la prevalencia de CIPC fue de 0,2% (IC95% 0,1-1) en las TC (1/507) y 1,7% (IC 95% 0,1-9) en las RMN (1/58). Los pacientes con PC inicialmente clasificados como "AGA o europea positivo" tuvieron una mayor probabilidad quirúrgica y esta decisión se tomó antes en el seguimiento. CONCLUSIONES: En nuestra cohorte, la prevalencia de quistes pancreáticos incidentales y relevantes no fue despreciable, siendo cercana al 1% según las guías actuales

Prevalence of incidental clinically relevant pancreatic cysts at diagnosis based on current guidelines.

BACKGROUND: Most pancreatic cysts (PCs) found incidentally by CT and MRI scans might not be clinically important according to the Fukuoka guidelines, the American Gastroenterological Association (AGA) guidelines and European guidelines. AIMS: To determine and compare the prevalence of incidental clinically important PCs (CIPCs). METHODS: Abdominal contrast-enhanced CT or MRI scans performed during a one-year period were retrospectively reviewed to identify incidental PCs. CIPCs were defined as those cysts that would be capable of triggering further evaluation with endoscopic ultrasound, immediate surveillance (within 3-6 months) and/or surgery. Prevalence was calculated as the number of patients with CIPCs per 100 subjects imaged (%). RESULTS: Sixty patients (mean age 70±14 years) out of 565 were found to have incidental PCs, representing a prevalence of 8.7% (95% CI 6.3-11.5) in CT scans and 27.5% (95% CI 16-41) in MRI scans. Seven patients (11.6%, 95% CI 5-22) had CIPCs based on size ≥ 30mm (n=5), size ≥ 30mm and pancreatic duct (PD) dilation (n=1) and PD dilation and presence of solid component (n=1). Based on the Fukuoka guidelines, the prevalence of CIPCs was 1.2% (95% CI 0.4-2.5) in CT scans (6/507) and 1.7% (95% CI 0.1-9) in MRI scans (1/58). Based on the AGA and European guidelines, the prevalence of CIPCs was 0.2% (95% CI 0.1-1) in CT scans (1/507) and 1.7% (95% CI 0.1-9) in MRI scans (1/58). Patients with PCs initially classified as "AGA- or European-positive" had a higher surgical probability and this decision was taken earlier in the follow-up. CONCLUSIONS: In our cohort, the prevalence of important incidental pancreatic cysts was not negligible at around 1% according to current guidelines.

[Adrenal insufficiency in cirrhotic patients]. / Insuficiencia suprarrenal relativa en pacientes cirróticos.

Relative adrenal insufficiency (RAI) is a common finding in cirrhotic patients with severe sepsis, and increased mortality. Its significance is unknown in stable conditions. The aim of this study was to evaluate the prevalence of RAI in stable cirrhotic patients at different stages of the disease. Also, the impact of RAI on the survival was evaluated and basal cortisol levels between plasma and saliva was correlated in control subjects and cirrhotic patients. Forty seven ambulatory patients and 16 control subjects were studied. RAI was defined as a serum cortisol increase of less than 9 υg/dl from baseline after the stimulation with 250 mg of synthetic ACTH. Twenty two had Child-Pugh = 8 and 25 = 9. The prevalence of RAI in patients with stable cirrhosis was 22%. A higher incidence of RAI was observed in patients with a Child-Pugh = 9 (8/32) than in those with = 8 (3/13, p < 0.05). A correlation between salivary cortisol and basal plasma cortisol (r = 0.6, p < 0.0004) was observed. Finally, survival at 1 year (97%) and 3 years (91%) was significantly higher without RAI than those who developed this complication (79% and 51%, p < 0.05, respectively). In summary, the prevalence of RAI is frequent in patients with stable cirrhosis and that it is related to the severity of liver diseaseand increased mortality.

The Use of Standard Gastrointestinal Endoscopic Ultrasound to Assess Cardiac Anatomy.

In this prospective observational study, conducted at an academic medical center, we evaluated the feasibility of performing a basic transesophageal echocardiography (TEE) examination using endoscopic ultrasound (EUS) technology to determine what cardiac structures could be assessed. This may be potentially beneficial during hemodynamic emergencies in the endoscopy suite resulting from hypovolemia, depressed ventricular function, aortic dissection, pericardial effusions, or aortic stenosis. Of the 20 patients enrolled, 18 underwent EUS with a linear echoendoscope for standard clinical indications followed by a cardiac assessment performed under the guidance of a TEE-certified cardiac anesthesiologist. Eight of the 20 standard views of cardiovascular structures per the 1999 American Society of Echocardiography/Society of Cardiovascular Anesthesiologists guidelines for TEE could be obtained using the linear echoendoscope. The following cardiac valvular structures were visualized: aortic valve (100%), mitral valve (100%), tricuspid valve (33%), and pulmonic valve (11%). Left ventricular and right ventricular systolic function could be assessed in 89% and 67% of patients, respectively. Other structures such as the ascending and descending aorta, pericardium, left atrial appendage, and interatrial septum were identified in 100% of patients. Doppler-dependent functions could not be assessed. Given that the EUS images were not directly compared with TEE in these patients, we cannot comment definitively on the quality of these assessments and further studies would need to be performed to make a formal comparison. Based on this study, EUS technology can consistently assess the mitral valve, aortic valve, aorta, pericardium, and left ventricular function. Given its limitations, EUS technology, although not a substitute for formal echocardiography, could be a helpful early diagnostic tool in an emergency setting.

Insuficiencia suprarrenal relativa en pacientes cirróticos / Adrenal insufficiency in cirrhotic patients

La insuficiencia suprarrenal relativa (ISR) es frecuente en pacientes cirróticos con sepsis grave, asociándose a un pobre pronóstico. Se desconoce su importancia en condiciones de enfermedad estable. El objetivo del trabajo ha sido evaluar la prevalencia de la ISR en una serie de pacientes cirróticos estables y su relación con el deterioro de la función hepática. Se determinó el impacto de la ISR en la supervivencia y se correlacionaron los niveles entre el cortisol basal en plasma y saliva en sujetos controles y cirróticos. Fueron incluidos 47 pacientes ambulatorios y 16 controles. La funcionalidad del eje hipotalámico-pituitario-suprarrenal se valoró mediante la prueba de estimulación con 250 μg de ACTH sintética EV, definiendo la ISR como delta cortisol < 9 μg/dl. Respecto al grado de deterioro de la función hepática, 22 tenían un Child-Pugh ≤ 8 y 25 pacientes = 9. La prevalencia de ISR fue de un 22%, siendo significativamente más elevada en aquellos con mayor deterioro de la función hepática (8/32 vs. 3/13, p < 0.05). Se observó correlación entre el cortisol salival y el plasmático basal (r = 0.6, p < 0.0004). Por último, la supervivencia fue más elevada en los pacientes sin ISR al año (97%) y a los tres años (91%) que aquellos que desarrollaron esta complicación (79 % y 51%, p < 0.05, respectivamente). En resumen, la prevalencia de ISR es elevada en los pacientes con cirrosis estable y se relaciona con un deterioro de la función hepática y una mayor mortalidad.

Relative adrenal insufficiency (RAI) is a common finding in cirrhotic patients with severe sepsis, and increased mortality. Its significance is unknown in stable conditions. The aim of this study was to evaluate the prevalence of RAI in stable cirrhotic patients at different stages of the disease. Also, the impact of RAI on the survival was evaluated and basal cortisol levels between plasma and saliva was correlated in control subjects and cirrhotic patients. Forty seven ambulatory patients and 16 control subjects were studied. RAI was defined as a serum cortisol increase of less than 9 μg/dl from baseline after the stimulation with 250 mg of synthetic ACTH. Twenty two had Child-Pugh ≤ 8 and 25 = 9. The prevalence of RAI in patients with stable cirrhosis was 22%. A higher incidence of RAI was observed in patients with a Child-Pugh = 9 (8/32) than in those with ≤ 8 (3/13, p < 0.05). A correlation between salivary cortisol and basal plasma cortisol (r = 0.6, p < 0.0004) was observed. Finally, survival at 1 year (97%) and 3 years (91%) was significantly higher without RAI than those who developed this complication (79% and 51%, p < 0.05, respectively). In summary, the prevalence of RAI is frequent in patients with stable cirrhosis and that it is related to the severity of liver diseaseand increased mortality.

Risk of Metachronous Advanced Neoplastic Lesions in Patients with Sporadic Sessile Serrated Adenomas Undergoing Colonoscopic Surveillance.

OBJECTIVES: The risk of developing metachronous advanced neoplastic lesions (ANLs) during surveillance after resection of sessile serrated adenomas (SSAs) has not been quantified. METHODS: Patients with sporadic SSAs resected between 1 April 2007 and 31 December 2009 who underwent surveillance colonoscopy in our institution were prospectively evaluated. Patients with low-risk adenomas (LRAs), high-risk adenomas (HRAs), and negative index colonoscopy (NIC) during the same period were identified using the pathology database and electronic medical records, and were also included as a comparison cohort. The primary outcome was the comparison of the study groups with regard to incidence of metachronous ANLs during surveillance colonoscopy. RESULTS: A total of 185 patients had SSAs, of whom 75 with 101 resected polyps were finally included. The comparison cohort consisted of 564 patients: 140 LRAs (160 polyps), 87 HRAs (478 polyps), and 337 NICs. The overall mean colonoscopy follow-up was for 54.5 months (±s.d. 14). SSA patients with synchronous HRA on index colonoscopy presented a higher incidence rate of metachronous ANL (12.96 per 1,000 person-months) compared with patients with HRA (5.07 per 1,000 person-months), whereas those with synchronous LRA and without synchronous adenoma on index colonoscopy presented a low incidence rate of metachronous ANL (0 and 1.41 per 1,000 person-months, respectively) similar to LRA (1.47 per 1,000 person-months). Among patients with SSA the 3- and 5-year ANL free-cumulative probability was 64.3 and 32.1% in those with synchronous HRA, 100 and 100% in those with synchronous LRA, and 95.1 and 91.7% if no synchronous adenoma was found. CONCLUSIONS: Among patients with resected sporadic SSAs the risk of developing metachronous ANL is influenced by the presence of synchronous HRA on index colonoscopy. Patients with SSAs and synchronous HRA on index colonoscopy require closer surveillance, whereas those with synchronous LRA and those without synchronous adenomas may be followed up in the same way as those with LRAs.

La colonoscopia en la pesquisa de cáncer colorrectal / Colonoscopy in screening for colorectal cancer

El cáncer colorrectal representa una de las primeras causas de muerte por cáncer en todo el mundo y también en la Argentina. En los últimos años la pesquisa de cáncer de colon ha cobrado gran importancia y se ha postulado a la colonoscopia como el patrón de oro. En esta revisión resumimos las evidencias de este método poniendolo en contexto con las complicaciones y desventajas.

Colorectal cancer is one of the leading causes of cancer deathworldwide and also in Argentina. In the past few years colorectalcancer screening has become more popular and colonoscopyhas been postulated as the gold standard. In thisreview we analyzed the evidence supporting this methodin contrast with its complications and disadvantages.

[Endoscopic ultrasound-guided choledocho-duodenostomy in advanced pancreatic cancer with duodenal obstruction]. / Colédoco-duodenostomía guiada por ecoendoscopía en cáncer de páncreas avanzado con obstrucción duodenal.

Endoscopic retrograde cholangiopancreatography (ERCP) is considered the first-approach for biliary drainage. In cases of ERCP failure, patients are usually referred for percutaneous transhepatic biliary drainage or surgical biliary bypass. In the last decade, the indications of endoscopic ultrasound (EUS) in the management of patients with pancreatic cancer have increased, and numerous cases of EUS-guided biliary drainage have been reported in patients with failures during the ERCP. Our goal is to report a patient with locally advanced pancreatic cancer who presented with painless jaundice and cholestasis with biliary and duodenal obstruction. A EUS-guided choledochoduodenostomy was performed by placement of a self-expanding metal stent.

Colédoco-duodenostomía guiada por ecoendoscopia en cáncer de páncreas avanzado con obstrucción duodenal / Endoscopic ultrasound-guided choledocho-duodenostomy in advanced pancreatic cancer with duodenal obstruction

La colangiopancreatografía retrógrada endoscópica (CPRE) se considera el tratamiento de primera línea para el drenaje biliar en pacientes con cáncer de páncreas. En los casos de fracaso por CPRE, generalmente se realiza un drenaje biliar transparietohepático o una derivación biliar quirúrgica. En la última década, las indicaciones y la utilidad de la ecoendoscopia en pacientes con cáncer de páncreas han ido creciendo, y se han informado numerosos casos de drenajes biliares guiados por ecoendoscopia como una alternativa al drenaje biliar percutáneo o quirúrgico en fracasos en la CPRE. Nuestro objetivo es comunicar un caso con cáncer de páncreas localmente avanzado que se presentó con ictericia indolora y síndrome coledociano con obstrucción biliar y duodenal, en el que se realizó una colédoco-duodenostomía guiada por ecoendoscopia mediante la colocación de una prótesis metálica autoexpandible.

Endoscopic retrograde cholangiopancreatography (ERCP) is considered the first-approach for biliary drainage. In cases of ERCP failure, patients are usually referred for percutaneous transhepatic biliary drainage or surgical biliary bypass. In the last decade, the indications of endoscopic ultrasound (EUS) in the management of patients with pancreatic cancer have increased, and numerous cases of EUS-guided biliary drainage have been reported in patients with failures during the ERCP. Our goal is to report a patient with locally advanced pancreatic cancer who presented with painless jaundice and cholestasis with biliary and duodenal obstruction. A EUS-guided choledochoduodenostomy was performed by placement of a self-expanding metal stent.

Meal ingestion markedly increases liver stiffness suggesting the need for liver stiffness determination in fasting conditions / / La ingesta de una comida ocasiona un aumento de la rigidez hepática, lo que sugiere que esta determinación debe ser siempre evaluada en ayuna

Introduction: The introduction of noninvasive liver stiffness (LS) determination has heralded a new stage in the diagnosis and treatment of liver fibrosis. Aim: We evaluated the effect of food intake on LS in patients with different degrees of liver disease. Patients and methods: We evaluated 24 patients (F≤1, n = 11 and F> 1, n = 13). LS (Fibroscan®) and portal blood flow (PBF) (Doppler ultrasound) were studied before and 30 min after ingestion of a standard liquid meal. Results: Food intake increased PBF (51 ± 10%, p < 0.001). Splanchnic hyperemia was accompanied by a significant rise in LS (from 7.8 ± 3.3 to 10.3 ± 4.1 kPa, p < 0.001). These increases were similar in patients with minimal fibrosis(F≤1) and in those with more advanced fibrosis or cirrhosis (F > 1). Hemodynamic and LS values returned to baseline pre-meal levels within 2 hours. Conclusion: LS increases markedly after ingestion of a standard meal, irrespective of the degree of fibrosis. Our results strongly suggest that LS should be measured in fasting conditions (AU)

Introducción: El desarrollo de nuevos métodos que permiten la determinación no invasiva de la rigidez hepática ha abierto una nueva era en el manejo de la fibrosis hepática. Objetivo: El objetivo del trabajo fue evaluar el efecto de ingesta de una comida sobre la rigidez hepática en pacientes con diferentes grados de fibrosis. Pacientes y métodos: Se evaluaron 24 pacientes (F ≤ 1, n = 11, y F > 1, n = 13), que fueron estudiados basalmente y 30 min después de la ingesta de una comida estándar (Ensure Plus®). La rigidez hepática se midió por Fibroscan®, y los parámetros hemodinámicos portales, mediante Doppler. La ingesta de una comida ocasionó un aumento del flujo sanguíneo portal (51 ± 10%, p < 0,001). La hiperemia esplácnica fue acompañada por un marcado incremento en la rigidez hepática (7,8 ± 3,3 a 10,3 ± 4,1 kPa, p < 0,001). Este efecto fue similar en pacientes con fibrosis mínima (F ≤ 1) y con fibrosis significativa (F > 1). Los valores de ambos parámetros retornaron a niveles similares a los basales a las 2 h luego de la ingesta. Conclusión: Este estudio demuestra que la respuesta vascular posprandial se acompaña de aumento de la rigidez hepática. Los cambios son independientes del grado de fibrosis. Nuestros resultados sugieren fuertemente que los estudios deben realizarse en condiciones de ayuno (AU)