494 resultados para Endoprothèse (stent)
Resumo:
Owing to an increased risk of aging population and a higher incidence of coronary artery disease (CAD), there is a need for more reliable and safer treatments. Numerous varieties of durable polymer-coated drug eluting stents (DES) are available in the market in order to mitigate in-stent restenosis. However, there are certain issues regarding their usage such as delayed arterial healing, thrombosis, inflammation, toxic corrosion by-products, mechanical stability and degradation. As a result, significant amount of research has to be devoted to the improvement of biodegradable polymer-coated implant materials in an effort to enhance their bioactive response. In this investigation, magneto-electropolished (MEP) and a novel biodegradable polymer coated ternary Nitinol alloys, NiTiTa and NiTiCr were prepared to study their bio and hemocompatibility properties. The initial interaction of a biomaterial with its surroundings is dependent on its surface characteristics such as, composition, corrosion resistance, work of adhesion and morphology. In-vitro corrosion tests such as potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) studies were conducted to determine the coating stability and longevity. In-vitro hemocompatibility studies and HUVEC cell growth was performed to determine their thrombogenic and biocompatibility properties. Critical delamination load of the polymer coated Nitinol alloys was determined using Nano-scratch analysis. Sulforhodamine B (SRB) assays were performed to elucidate the effect of metal ions leached from Nitinol alloys on the viability of HUVEC cells. Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), contact angle meter and X-ray diffraction (XRD) were used to characterize the surface of the alloys. MEP treated and polymer coated (PC) Nitinol alloys displayed a corrosion resistant polymer coating as compared to uncoated alloys. MEP and PC has resulted in reduced Ni and Cr ion leaching from NiTi5Cr and subsequently low cytotoxicity. Thrombogenicity tests revealed significantly less platelet adhesion and confluent endothelial cell growth on polymer coated and uncoated ternary MEP Nitinol alloys. Finally, this research addresses the bio and hemocompatibility of MEP + PC ternary Nitinol alloys that could be used to manufacture blood contacting devices such as stents and vascular implants which can lead to lower U.S. healthcare spending.
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INTRODUCTION AND OBJECTIVES: The aim of the present paper was to report trends in coronary angioplasty for the treatment of ST-elevation myocardial infarction (STEMI) in Portugal. METHODS: Prospective multicenter data from the Portuguese National Registry of Interventional Cardiology (RNCI) and official data from the Directorate-General for Health (DGS) were studied to analyze percutaneous coronary intervention (PCI) procedures for STEMI from 2002 to 2013. RESULTS: In 2013, 3524 primary percutaneous coronary intervention (p-PCI) procedures were performed (25% of all procedures), an increase of 315% in comparison to 2002 (16% of all interventions). Between 2002 and 2013 the rate increased from 106 to 338 p-PCIs per million population per year. Rescue angioplasty decreased from 70.7% in 2002 to 2% in 2013. During this period, the use of drug-eluting stents grew from 9.9% to 69.5%. After 2008, the use of aspiration thrombectomy increased, reaching 46.7% in 2013. Glycoprotein IIb-IIIa inhibitor use decreased from 73.2% in 2002 to 23.6% in the last year of the study. Use of a radial approach increased steadily from 8.3% in 2008 to 54.6% in 2013. CONCLUSION: During the reporting period there was a three-fold increase in primary angioplasty rates per million population. Rescue angioplasty has been overtaken by p-PCI as the predominant procedure since 2006. New trends in the treatment of STEMI were observed, notably the use of drug-eluting stents and radial access as the predominant approach.
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Introdução: O tratamento endovascular da aorta torácica (TEVAR) é uma modalidade terapêutica emergente que tem vindo a revolucionar a abordagem de diferentes tipos de patologia da aorta na sua localização torácica. Objetivos: Avaliação da experiência institucional do serviço de angiologia e cirurgia vascular. Métodos: Análise retrospetiva da série consecutiva de todos os doentes com patologia da aorta torácica e/ou toracoabdominal submetidos a TEVAR na nossa instituição. Foram excluídos aqueles com uso concomitante de endopróteses fenestradas/ramificadas abdominais. Resultados: Desde abril de 2005 até abril de 2014, 79 doentes foram submetidos a TEVAR, com idade média de 66 ± 12,83 anos (máx: 86; mín: 14). As indicações incluíram: 46 aneurismas (58%), 17 dissecções aórticas clássicas tipo B (22%), 13 no contexto de outras síndromes aórticas agudas (16%), 2 por ateroembolismo (3%) e um por fístula aortoesofágica (1%). Na patologia aneurismática, a distribuição anatómica da doença foi a seguinte: 5 na aorta ascendente e arco aórtico (11%), 35 na aorta torácica descendente (76%) e 6 toracoabdominal (13%). O diâmetro médio das dilatações aneurimáticas foi de 69,64 mm (máx: 150 mm). A rotura foi uma apresentação da patologia em 21,5% dos doentes (n = 17); 20,9% dos doentes tinham antecedentes de cirurgia aórtica prévia. A dissecção aórtica tipo B complicada foi a segunda indicação mais comum, sendo de apresentação aguda em 13 (76%) e crónica em 4 (24%). As complicações na base da intervenção foram dilatação aneurismática em 35% (n = 6), malperfusão com isquemia de órgão alvo 47% (n = 8), desconhecida em 18% (n = 3). Foi realizada extensão distal com stent descoberto (Petticoat) em 9 casos (41,2%) e foram realizados procedimentos adjuvantes em 18% (stenting renal n = 2; stenting ilíaco n = 1). Dentro das outras síndromes aórticas agudas, o TEVAR foi realizado no contexto de úlcera aórtica penetrante (n = 4), hematoma intramural (n = 4) e os restantes por rotura/pseudoaneurisma (n = 5). As endopróteses utilizadas foram: 32 Valiant Medtronic®, 15 TAG Gore®, 25 Zenith TX2 Cook®, 2 Zenith TX1 Cook®, uma Relay Plus®, 3 Talent Medtronic® e outras em 1%. A mediana de dias de cuidados intensivos foi 2 (intervalo 0-42) e a mediana de suporte tranfusional foi de 2 UCE. A taxa de mortalidade aos 30 dias ou intra-hospital foi de 18% (n = 14). Atendendo ao timing da cirurgia, a taxa de mortalidade aferida nos casos electivos foi de 8% (4/50) e nos urgentes atinge os 35% (10/29). Intraoperatoriamente foram tratadas 7 complicações relacionadas com vaso de acesso membro, 2 casos de dissecção aórtica iatrogénica, um caso de trombose arterial inferior e um endoleak tipo IA. A taxa de reintervenções foi de 17%, com as seguintes indicações: 9 endoleaks, 2 isquemias mesentéricas e 2 fístulas aortoesofágicas. Conclusões: A série apresentada traduz uma experiência institucional favorável com resultados reprodutíveis e que o TEVAR é um procedimento seguro e eficaz para o tratamento de diferentes patologias da aorta torácica, quando comparado com o tratamento cirúrgico aberto.
Resumo:
Introdução: A oclusão da artéria hipogástrica pode ser necessária na reparação endovascular de aneurismas da aorta abdominal (EVAR). A oclusão intencional da hipogástrica pode ter complicações isquémicas. As endopróteses de bifurcação ilíaca (IBD) surgiram como alternativa endovascular à oclusão da hipogástrica em doentes com elevado risco para isquemia pélvica. Os autores descrevem um caso de oclusão precoce do ramo hipogástrico de IBD com graves consequências clínicas. Caso clínico: Sexo masculino, de 74 anos, com aneurisma da aorta abdominal (diâmetro máximo de 55 mm) com envolvimento de ambas as bifurcações ilíacas e segmentos proximais das hipogástricas (diâmetro máximo de 31 e 32 mm), submetido a EVAR com revascularização hipogástrica esquerda via IBD (Cook Zenith®) e coiling+overstenting da artéria hipogástrica contralateral. O procedimento decorreu sem complicações e a angiografia final mostrava permeabilidade da hipogástrica revascularizada e escassa colateralidade pélvica. O pós-operatório imediato complicou-se de dor lombar e glútea bilateral associada a manifestações cutâneas isquémicas e monoparesia do membro inferior esquerdo. Por agravamento progressivo nas primeiras 24h e angioTC com oclusão do stent da hipogástrica esquerda, procedeu-se novamente a revascularização da hipogástrica, com bom resultado na angiografia final. Apesar da revascularização bem-sucedida, houve agravamento progressivo do estado geral, com isquemia pélvica irreversível e rabdomiólise. Óbito ao 5.◦dia pós-operatório. Conclusão: A isquemia pélvica aguda é uma complicação grave e frequentemente fatal que pode advir da oclusão bilateral das artérias hipogástricas. A falência da revascularização por IBD pode ser fatal, pelo que os autores aconselham um cuidado redobrado no controlo angiográfico final e um baixo limiar para investigação na suspeita de complicações pós-operatórias. Se maior risco de falência técnica, embolização ou escassa colateralidade pélvica, a preservação bilateral de fluxo nas artérias hipogástricas pode estar recomendada.
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L’ingénierie des biomatériaux a connu un essor prodigieux ces dernières décennies passant de matériaux simples à des structures plus complexes, particulièrement dans le domaine cardiovasculaire. Cette évolution découle de la nécessité des biomatériaux de permettre la synergie de différentes propriétés, dépendantes de leurs fonctions, qui ne sont pas forcément toutes compatibles. Historiquement, les premiers matériaux utilisés dans la conception de dispositifs médicaux étaient ceux présentant le meilleur compromis entre les propriétés physico-chimiques, mécaniques et biologiques que nécessitait leur application. Cependant, il se peut qu’un tel dispositif possède les bonnes propriétés physico-chimiques ou mécaniques, mais que sa biocompatibilité soit insuffisante induisant ainsi des complications cliniques. Afin d’améliorer ces propriétés biologiques tout en conservant les propriétés de volume du matériau, une solution est d’en modifier la surface. L’utilisation d’un revêtement permet alors de moduler la réponse biologique à l’interface biomatériau-hôte et de diminuer les effets indésirables. Ces revêtements sont optimisés selon deux critères principaux : la réponse biologique et la réponse mécanique. Pour la réponse biologique, les deux approches principales sont de mettre au point des revêtements proactifs qui engendrent l’adhérence, la prolifération ou la migration cellulaire, ou passifs, qui, principalement, sont inertes et empêchent l’adhérence de composés biologiques. Dans certains cas, il est intéressant de pouvoir favoriser certaines cellules et d’en limiter d’autres, par exemple pour lutter contre la resténose, principalement due à la prolifération incontrôlée de cellules musculaires lisses qui conduit à une nouvelle obstruction de l’artère, suite à la pose d’un stent. La recherche sur les revêtements de stents vise, alors, à limiter la prolifération de ces cellules tout en facilitant la ré-endothélialisation, c’est-à-dire en permettant l’adhérence et la prolifération de cellules endothéliales. Dans d’autres cas, il est intéressant d’obtenir des surfaces limitant toute adhérence cellulaire, comme pour l’utilisation de cathéter. Selon leur fonction, les cathéters doivent empêcher l’adhérence cellulaire, en particulier celle des bactéries provoquant des infections, et être hémocompatibles, principalement dans le domaine vasculaire. Il a été démontré lors d’études précédentes qu’un copolymère à base de dextrane et de poly(méthacrylate de butyle) (PBMA) répondait aux problématiques liées à la resténose et qu’il possédait, de plus, une bonne élasticité, propriété mécanique importante due à la déformation que subit le stent lors de son déploiement. L’approche de ce projet était d’utiliser ce copolymère comme revêtement de stents et d’en améliorer l’adhérence à la surface en formant des liens covalents avec la surface. Pour ce faire, cela nécessitait l’activation de la partie dextrane du copolymère afin de pouvoir le greffer à la surface aminée. Il était important de vérifier pour chaque étape l’influence des modifications effectuées sur les propriétés biologiques et mécaniques des matériaux obtenus, mais aussi d’un point de vue de la chimie, l’influence que cette modification pouvait induire sur la réaction de copolymérisation. Dans un premier temps, seul le dextrane est considéré et est modifié par oxydation et carboxyméthylation puis greffé à des surfaces fluorocarbonées aminées. L’analyse physico-chimique des polymères de dextrane modifiés et de leur greffage permet de choisir une voie de modification préférentielle qui n’empêchera pas ultérieurement la copolymérisation. La carboxyméthylation permet ainsi d’obtenir un meilleur recouvrement de la surface tout en conservant la structure polysaccharidique du dextrane. Le greffage du dextrane carboxyméthylé (CMD) est ensuite optimisé selon différents degrés de modification, tenant compte aussi de l’influence que ces modifications peuvent induire sur les propriétés biologiques. Finalement, les CMD précédemment étudiés, avec des propriétés biologiques définies, sont copolymérisés avec des monomères de méthacrylate de butyle (BMA). Les copolymères ainsi obtenus ont été ensuite caractérisés par des analyses physico-chimiques, biologiques et mécaniques. Des essais préliminaires ont montrés que les films de copolymères étaient anti-adhérents vis-à-vis des cellules, ce qui a permis de trouver de nouvelles applications au projet. Les propriétés élastiques et anti-adhérentes présentées par les films de copolymères CMD-co-PBMA, les rendent particulièrement intéressants pour des applications comme revêtements de cathéters.
Resumo:
Common bile duct stones can be treated with normal endoscopic techniques. Where stones cannot be removed due to their size or number or due to stenosis of the common bile duct, a plastic stent can be inserted, enabling rapid drainage of bile. At the three-month check-up complete removal of the stones was found in 41 (85.4%) of the 48 patients with difficult choledocholithiasis. In the remaining 7 patients (14.6%), the stent in any case resulted in clinical improvement. A permanent stent was necessary in 4 patients, enabling safe drainage with no complications. The use of endoscopy for stent placement was effective in all our cases of difficult coledocholithiasis without any complications.
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The incidence of anastomotic stricture following colorectal surgery has increased in recent years. This complication is observed in 2-5% of all operated patients and is probably due to the greater number of low anastomoses performed with surgical staplers. We observed 31 patients with postoperative stricture, arising from one to nine months post-surgery. All patients had been treated for colorectal cancer and underwent endoscopy either during routine follow-up or for symptoms of stenosis. In 16 patients (group A) the stricture diameter was less than 4 mm and the patients had symptoms attributable to partial bowel obstruction. In the remaining 15 patients (group B), who had difficult bowel movements, the stricture diameter ranged from 4 to 8 mm. All patients were treated with endoscopic dilation using achalasia balloons. The results were considered good when the post-dilation anastomosis diameter achieved was at least 13 mm, fair when it was 9-12 mm and poor when it was less than 9 mm. The short term results (3 weeks) were good in 27 patients (87.2%), fair in 3 patients (9.6%), and poor in 1 patient (3.2%). After several unsuccessful dilations, the latter was treated by surgery. Follow-up at 3-4 months of the remaining 30 patients revealed good results in 20 (66.6%), fair in 6 (20%), and poor in 4 (13.3%). In 1 of these 4 patients, cancer recurrence was observed and a new surgical resection was performed. In 2 patients a self–expandable metal stent was inserted for 4-6 weeks, with satisfactory results. In 1 patient a biodegradable polydioxanone stent was inserted with good results after 6 months. Follow-up at 3-4 months showed good results in 25 patients. After 38 months, cancer recurrence in the area of the anastomosis was observed in 1 patient, who was treated surgically. Endoscopic dilatation should be considered the first therapeutic approach in case of anastomotic strictures, as it is immediately effective, repeatable, and does not preclude surgery if this should become necessary. .
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Background and aim: This article provides a practical review to undertaking safe endoscopic ampullectomy and highlights some of the common difficulties with this technique as well as offering strategies to deal with these challenges. Methods: We conducted a review of studies regarding endoscopic ampullectomy for ampullary neoplasms with special focus on techniques. Results: Accurate preoperative diagnosis and staging of ampullary tumors is imperative for predicting prognosis and determining the most appropriate therapeutic approach. The optimal technique for endoscopic ampullectomy is dependent on the lesions size. En bloc resection is recommended for lesions confined to the papilla. There is no significant evidence to support the submucosal injection before ampullectomy. There is no consensus regarding the optimal current and power output for endoscopic ampulectomy. The benefits of a thermal adjunctive therapy remain controversial. A prophylactic pancreatic stent reduces the incidence and severity of pancreatitis post-ampullectomy. Conclusions: Endoscopic ampullectomy is a safe and efficacious therapeutic procedure for papillary adenomas in experienced endoscopist and it can avoid the need for surgical intervention.
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This thesis presents an investigation on endoscopic optical coherence tomography (OCT). As a noninvasive imaging modality, OCT emerges as an increasingly important diagnostic tool for many clinical applications. Despite of many of its merits, such as high resolution and depth resolvability, a major limitation is the relatively shallow penetration depth in tissue (about 2∼3 mm). This is mainly due to tissue scattering and absorption. To overcome this limitation, people have been developing many different endoscopic OCT systems. By utilizing a minimally invasive endoscope, the OCT probing beam can be brought to the close vicinity of the tissue of interest and bypass the scattering of intervening tissues so that it can collect the reflected light signal from desired depth and provide a clear image representing the physiological structure of the region, which can not be disclosed by traditional OCT. In this thesis, three endoscope designs have been studied. While they rely on vastly different principles, they all converge to solve this long-standing problem.
A hand-held endoscope with manual scanning is first explored. When a user is holding a hand- held endoscope to examine samples, the movement of the device provides a natural scanning. We proposed and implemented an optical tracking system to estimate and record the trajectory of the device. By registering the OCT axial scan with the spatial information obtained from the tracking system, one can use this system to simply ‘paint’ a desired volume and get any arbitrary scanning pattern by manually waving the endoscope over the region of interest. The accuracy of the tracking system was measured to be about 10 microns, which is comparable to the lateral resolution of most OCT system. Targeted phantom sample and biological samples were manually scanned and the reconstructed images verified the method.
Next, we investigated a mechanical way to steer the beam in an OCT endoscope, which is termed as Paired-angle-rotation scanning (PARS). This concept was proposed by my colleague and we further developed this technology by enhancing the longevity of the device, reducing the diameter of the probe, and shrinking down the form factor of the hand-piece. Several families of probes have been designed and fabricated with various optical performances. They have been applied to different applications, including the collector channel examination for glaucoma stent implantation, and vitreous remnant detection during live animal vitrectomy.
Lastly a novel non-moving scanning method has been devised. This approach is based on the EO effect of a KTN crystal. With Ohmic contact of the electrodes, the KTN crystal can exhibit a special mode of EO effect, termed as space-charge-controlled electro-optic effect, where the carrier electron will be injected into the material via the Ohmic contact. By applying a high voltage across the material, a linear phase profile can be built under this mode, which in turn deflects the light beam passing through. We constructed a relay telescope to adapt the KTN deflector into a bench top OCT scanning system. One of major technical challenges for this system is the strong chromatic dispersion of KTN crystal within the wavelength band of OCT system. We investigated its impact on the acquired OCT images and proposed a new approach to estimate and compensate the actual dispersion. Comparing with traditional methods, the new method is more computational efficient and accurate. Some biological samples were scanned by this KTN based system. The acquired images justified the feasibility of the usage of this system into a endoscopy setting. My research above all aims to provide solutions to implement an OCT endoscope. As technology evolves from manual, to mechanical, and to electrical approaches, different solutions are presented. Since all have their own advantages and disadvantages, one has to determine the actual requirements and select the best fit for a specific application.
Resumo:
Background: Postoperative esophageal leaks have a high morbidity and mortality. Self-expanding metal stents (SEMS) have been used as an alternative to re-operation. Aim: Evaluating predictors of success of SEMS in postoperative esophageal leaks. Methods: Retrospective study of patients with postoperative esophageal leaks referred for SEMS placement in a reference center during a period of 3 years. Technical success was defined as closure of the leak in barium swallow at 15 days. Clinical success was considered as endoscopic and/or radiographic confirmation of closure after stent removal. Results: Thirteen patients placed SEMS. Median follow-up was 58 days. Leaks had a median size of 20 mm. Time between surgery and SEMS placement was 20 days. One patient died 2 days after SEMS placement and one had worsening of the fistula after SEMS expansion. Time till stent migration was 9 days. Technical success was achieved in 9 of 11 patients, with clinical success without recurrence in 5 patients. All leaks with less than 20 mm were solved endoscopically. Technical and clinical success was higher when time between surgery and SEMS placement was lower, even though without statistical significance (respectively, p = 0.228 and 0.374). In the 8 patients who died during follow-up, median survival was 59 days. Conclusions: Technical success of SEMS was higher than 80%; however, due to high morbidity and mortality, only 45% of patients had their stent removed. Lower time from diagnosis to SEMS placement and leak size less than 20 mm may be associated with better results.
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Pediatric coronary artery bypass surgery gained wide acceptance with the introduction of internal thoracic arteries (ITAs) for bypass operations for post Kawasaki disease (KD) lesions. The technique is now established as the standard surgical choice, and its safety even in infancy, graft patency, growth potential, graft longevity and clinical efficacy have been well documented. In this article the author reviews the development of pediatric coronary bypass as the main indication for the treatment of coronary lesions due to KD. I believe that coronary revascularization surgery in pediatric population utilizing uni- or bilateral ITAs is the current gold-standard as the most reliable treatment, although percutaneous coronary intervention with or without a stent has been tried with vague long-term results in children.
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La derivación portosistémica intrahepática transyugular (TIPS) es una técnica importante en el manejo de las complicaciones de la hipertensión portal, en especial en aquellos pacientes candidatos a trasplante hepático. Se trata de un estudio observacional analítico, sin riesgo, en el cual se emplearon técnicas y métodos de investigación documental retrospectivo, y no se realizó ningún tipo de intervención sobre las variables fisiológicas, psicológicas y sociales de la población incluida. Se realizó la descripción demográfica de los pacientes, características clínicas, hallazgos imageneológicos y aspectos técnicos asociados al procedimiento de los pacientes con hipertensión portal que han sido manejados con TIPS en la Fundación CardioInfantil desde Enero 1 de 2007 hasta Junio 30 de 2016. Se incluyeron 54 pacientes de los cuales el 66,7% no presentaron complicaciones inmediatas, tenidas en cuenta desde la terminación del procedimiento y hasta las siguientes 24 horas; sin embargo, 16,9% debutaron con encefalopatía durante este periodo. De las complicaciones tardías, la más frecuente fue la ascitis con un 66,7%, con una mortalidad de 20,4% de los cuales, el 45% de estos fue por shock séptico y falla orgánica secundaria. Aunque el porcentaje de complicaciones asociadas al procedimiento fue alto en nuestros pacientes, se encuentra dentro de los valores reportados en la literatura. Los resultados presentados son un punto de partida para la evaluación del procedimiento en nuestra población y permiten implementar estrategias de mejora que conlleven a incidir de manera positiva en el porcentaje de complicaciones y mortalidad derivadas del procedimiento.
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Introducción: El cáncer gástrico es uno de los más frecuentes a nivel mundial y Colombia se sitúa entre los países de mayor incidencia en este tipo de patología. Objetivo: Describir las características epidemiológicas, clínicas, el tratamiento administrado y los desenlaces inmediatos de los pacientes con diagnóstico de cáncer gástrico atendidos en el Hospital Universitario Mayor de Bogotá entre los años 2011 y 2014. Metodología: Se realizó un estudio observacional descriptivo con diagnóstico de cáncer gástrico. Se realizaron análisis univariados por medio de proporciones para las variables cualitativas y medidas de tendencia central para las variables cuantitativas según la distribución. Resultados: Un total de 189 pacientes fueron analizados. El dolor fue el síntoma más frecuente en los pacientes (30.7%) y el principal signo encontrado fue una masa palpable en abdomen (9,5%). Los pacientes fueron sometidos a diferentes abordajes terapéuticos, la mayoría recibieron manejo paliativo no quirúrgico (52.9%) y la opción quirúrgica más usada en los pacientes fue la gastrectomía total (20.6%), y la subtotal (16,4) seguidas de quimioterapia y/o radiación perioperatoria. Los pacientes que sobrevivieron a los 2 años fueron 7,4% del total. Conclusiones: El registro de los pacientes con cáncer gástrico es bueno en el Méderi-Hospital Universitario Mayor es bueno y permite caracterizar los pacientes, la presentación de la patología y los resultados del tratamiento que concuerdan con los presentados en contextos similares en la literatura.