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BACKGROUND: Endovascular management of portal vein thrombosis (PVT) is challenging. Transsplenic access (TSA) is growing as an access option to the portal system but with higher rates of bleeding complications. The aim of this article is to evaluate the efficacy and safety of transsplenic portal vein recanalization (PVR) using a metallic stent after pediatric liver transplantation. MATERIALS AND METHODS: This is a retrospective review of 15 patients with chronic PVT who underwent PVR via TSA between February 2016 and December 2020. Two children who had undergone catheterization of a mesenteric vein tributary by minilaparotomy were excluded from the patency analysis but included in the splenic access analysis. The technical and clinical success of PVR and complications related to the procedure via TSA were evaluated. RESULTS: Thirteen children with PVT were treated primarily using the TSA. The mean age was 4.1 years (range, 1.5-13.7 years), and the most common clinical presentation was hypersplenism (60%). Technically successful PVR was performed in 11/13 (84.6%) children, and clinical success was achieved in 9/11 (81.8%) children. No major complications were observed, and one child presented moderate pain in the TSA (from a total of 17 TSA). The median follow-up was 48.2 months. The median primary patency was 9.9 months. Primary patency in the first 4 years was 75%, and primary assisted patency was 100% in the follow-up period. CONCLUSIONS: Transsplenic PVR is a safe and effective method for the treatment of PVT after pediatric liver transplantation.

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Bradypus variegatus, the common sloth, belongs to the Bradypodidae family, being considered a biological model to be applied in multidisciplinary research. This study was developed with the aim of being applied to clinical medicine and to the adequate management of the common sloth. Ten sloths were utilized, obtained post-natural death. The animals were fixed and to obtain the results, they were submitted to the dissection technique. For 80% of the animals, the portal vein originated from five tributaries, which were: the resulting vein from the anastomosis of the cardia vein, fundic vein, and the pyloric branches; the mesenteric trunk; the vein formed by the confluence of the stomach body branches and the cranial portion of the cavity of the cardia; the pyloric vein and splenic vein. While in 20% of the animals, the portal vein was comprised of six tributaries, because the fundic vein and cardia vein form two direct anastomoses, arriving at the portal vein two tributary vessels. This pattern differs in number and arrangement of branches when compared to the main domestic species. Therefore, the hepatic portal system is responsible for the drainage of the stomach, spleen, pancreas and intestines.

Bradypus variegatus, a preguiça-comum, pertence à família Bradypodidae, sendo considerada um modelo biológico a ser aplicado em pesquisas multidisciplinares. Este estudo foi desenvolvido a fim de ser aplicado à clínica médica e ao manejo adequado da preguiça-comum. Foram utilizadas 10 preguiças, obtidas após morte natural. Os animais foram fixados e, para a obtenção dos resultados, submeteram-se à técnica de dissecação. Em 80% das observações, a veia porta originou-se a partir de cinco tributárias, são elas: a veia resultante da anastomose da veia cárdia, da veia fúndica e dos ramos pilóricos; o tronco mesentérico; a veia formada a partir da confluência de ramos do corpo estomacal e da porção cranial da cavidade cárdica; a veia pilórica e a veia esplênica. Enquanto em 20% dos animais a veia porta é constituída por seis tributárias, a veia fúndica e a veia cárdica formam duas anastomoses diretas, chegando à veia porta dois vasos tributários. Esse padrão difere em número e em disposição dos ramos, quando comparado ao das principais espécies domésticas. Portanto, o sistema porta hepático é responsável pela drenagem do estômago, do baço, do pâncreas e dos intestinos.

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ABSTRACT - BACKGROUND: Knowledge of the portal system and its anatomical variations aids to prevent surgical adverse events. The portal vein is usually made by the confluence of the superior mesenteric and splenic veins, together with their main tributaries, the inferior mesenteric, left gastric, and pancreaticoduodenal veins; however, anatomical variations are frequent. AIM: This article presents a literature review regarding previously described anatomical variations of the portal venous system and their frequency. METHODS: A systematic review of primary studies was performed in the databases PubMed, SciELO, BIREME, LILACS, Embase, ScienceDirect, and Scopus. Databases were searched for the following key terms: Anatomy, Portal vein, Mesenteric vein, Formation, Variation, Variant anatomic, Splenomesenteric vein, Splenic vein tributaries, and Confluence. RESULTS: We identified 12 variants of the portal venous bed, representing different unions of the splenic vein, superior mesenteric vein, and inferior mesenteric vein. Thomson classification of the end of 19th century refers to the three most frequent variants, with type I as predominant (M=47%), followed by type III (M=27.8%) and type II (M=18.6%). CONCLUSION: Thomson classification of variants is the most well-known, accounting for over 90% of portal venous variant found in clinical practice, inasmuch as the sum of the three junctions are found in over 93% of the patients. Even though rarer and accounting for less than 7% of variants, the other nine reported variations will occasionally be found during many abdominal operations.

RESUMO - RACIONAL: O conhecimento do sistema porta e de suas variações anatômicas contribui para prevenir acidentes cirúrgicos. Usualmente, a veia porta é formada pela confluência das veias mesentérica superior e esplênica, junto com suas principais tributárias: as veias mesentérica inferior, gástrica esquerda e pancreaticoduodenal. Entretanto, variações anatômicas são frequentes. OBJETIVO: Este artigo apresenta uma revisão da literatura em relação às variações anatômicas previamente descritas do sistema venoso porta e sua frequência. MÉTODOS: Foi realizada revisão sistemática de estudos primários nas bases de dados PubMed, Scielo, BIREME, LILACS, Embase, Science Direct e Scopus. As bases de dados foram pesquisadas pelas seguintes palavras-chave: Anatomia, Veia porta, Veia mesentérica, Formação, Variação, Variante anatômica, Veia esplenomesentérica, Veia esplênica, tributárias e Confluência. RESULTADOS: Foram identificadas doze variantes do sistema venoso portal, representando diferentes formações da veia esplênica, veia mesentérica superior e veia mesentérica inferior. A classificação de Thomson, do final do século XIX, refere três variantes mais frequentes, com predomínio do tipo I (M = 47%), seguido do tipo III (M = 27,8%) e do tipo II (M = 18,6%). CONCLUSÃO: A classificação de variantes de Thomson é a mais conhecida e responde por mais de 90% da variante venosa portal encontrada na prática clínica, na medida em que a soma das três junções é encontrada em mais de 93% dos pacientes. Embora mais raras e representando menos de 7% das variantes, as outras nove variações relatadas ocasionalmente serão encontradas durante muitas cirurgias abdominais.

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Resumen La hipertensión portal es un síndrome caracterizado por el incremento en el gradiente de presión portal, definido por la diferencia entre la presión de la porta y la vena cava inferior. Esta presión depende del flujo venoso y la resistencia vascular. En los pacientes cirróticos estas dos variables están alteradas de manera suprafisiológica, inicialmente por la lesión estructural dependiente de fibrosis y los nódulos de regeneración y posteriormente por cambios dinámicos vasculares que causan vasoconstricción intrahepática y vasodilatación esplácnica, lo cual explica las manifestaciones sistémicas de la cirrosis. La importancia de la hipertensión portal radica en la frecuencia y severidad de las complicaciones asociadas, especialmente la hemorragia variceal y otras como ascitis, peritonitis bacteriana espontanea, síndrome hepatorrenal y encefalopatía hepática. El objetivo de este artículo es realizar una revisión actualizada sobre el uso de las pruebas diagnósticas invasivas y no invasivas disponibles para el estudio de la hipertensión portal y su aplicación en la práctica clínica.

Abstract Portal hypertension is characterized by an increase in the portal pressure gradient, which is defined as the difference between the portal venous pressure and the pressure within the inferior vena cava. Such a pressure depends on venous flow and vascular resistance. In patients with cirrhosis, both variables are altered, initially due to fibrosis-dependent structural injury and regeneration nodules, and subsequently by vascular dynamic changes that cause intrahepatic vasoconstriction and splanchnic vasodilation, which explains the systemic manifestations of cirrhosis. The importance of portal hypertension lies in the frequency and severity of associated complications, especially variceal hemorrhage, but also ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, and hepatic encephalopathy. The objective of this article is to carry out an updated review on the use of invasive and non-invasive diagnostic tests available for the study of portal hypertension and their application in clinical practice.

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La hipertensión portal es un síndrome hemodinámico de la circulación venosa portal que condiciona múltiples complicaciones potencialmente mortales, debido a las alteraciones generadas en la circulación esplácnica y sistémica. En las últimas décadas se ha identificado la presencia de hipertensión portal en ausencia de cirrosis con un fenómeno de vasculopatía característico. Esta entidad puede clasificarse como prehepática, hepática y posthepática, según la localización del compromiso, identificado mediante estudios hemodinámicos. Se presentan cuatro casos de pacientes con hipertensión portal no cirrótica secundaria a trombosis portal. Adicionalmente, se realiza una revisión breve de la literatura, haciendo énfasis en las dos causas más frecuentes de hipertensión portal no cirrótica; la trombosis venosa portal crónica y la enfermedad vascular porto-sinusoidal.

Portal hypertension is a hemodynamic syndrome of the portal venous circulation that causes multiple life-threatening complications due to the alterations generated in the splanchnic and systemic circulation. In recent decades, the presence of portal hypertension in the absence of cirrhosis has been identified with a characteristic vasculopathy phenomenon. This condition can be classified as pre-hepatic, hepatic and post-hepatic, according to the location of the involvement, identified by hemodynamic studies. Four case reports of patients with non-cirrhotic portal hypertension secondary to portal thrombosis are presented. Additionally, a brief review of the literature is included, with emphasis in the two most frequent causes of non-cirrhotic portal hypertension; chronic portal venous thrombosis and portosinusoidal vascular disease.

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En este artículo se revisan los aspectos más importantes de la epidemiología, fisiopatología, abordaje diagnóstico y terapéutico de la trombosis del sistema venoso portal y mesentérico, para finalizar discutiendo la experiencia clínica de un caso a la luz de la literatura relevante. Esta complicación es usualmente relacionada con afecciones sistémicas y hepáticas, pero rara vez se presenta aislada y relacionada con el trauma. En ausencia de tratamiento adecuado durante la etapa aguda, la trombosis puede evolucionar hacia el infarto intestinal y la muerte del paciente. En casos crónicos, se ha asociado con la degeneración del sistema venoso portal hacia cambios por hipertensión portal crónica

This article reviews the epidemiology, pathophysiology, diagnostic and therapeutic approach of the portal and mesenteric venous system thrombosis, with a clinical case discussion considering the relevant literature. This complication is usually related to systemic and hepatic conditions, but rarely occurs isolated and related to trauma. In the absence of adequate treatment during the acute stage, thrombosis can progress to intestinal infarction and death. In chronic cases, it has been associated with degeneration of the portal venous system into changes due to chronic portal hypertension

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PURPOSE: To measure the distance between the right and middle hepatic veins and portal vein branches, in human cirrhotic liver casts. Was this measure actually smaller in the cirrhotic liver than in normal one? MATERIALS AND METHODS: This study was authorized by an area Research Ethics Committee, and each study subject or legal representative granted signed informed consent. Acrylic corrosion casts of 21 resected cirrhotic livers were generated. Diameters of hepatic veins and portal branches and pertinent intervening distances were measured. To assess differences in estimated average (relative to reference values), Student's t test for one sample was applied. RESULTS: Mean distances from right hepatic vein to the right portal branch and to portal vein bifurcation were 33 ± 6.4 and 36 ± 7.4 mm, respectively, both significantly less than published reference values in healthy human livers (p < 0.0001 and p < 0.0002, respectively). Mean distances from middle hepatic vein to right and left branches of portal vein were 36 ± 6.8 and 26 ± 8.8 mm, respectively. CONCLUSION: Distances separating right hepatic vein and portal vein (right branch and bifurcation) are diminished in cirrhotic livers compared to healthy ones. Given its caliber and proximity to portal branches, the middle hepatic vein remains as a reasonable alternative for TIPS procedures.

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O fígado está entre os múltiplos órgãos que podem ser afetados na pré-eclâmpsia, e a função hepática pode ser gravemente prejudicada na síndrome HELLP. A ultrassonografia com Doppler constitui um método não invasivo que pode ser usado para o estudo da circulação hepática durante a gravidez. Com o objetivo de apresentar as evidências científicas disponíveis sobre as alterações do fluxo hepático na gravidez, foi realizada pesquisa da literatura mundial por meio das bases de dados MEDLINE/PubMed e LILACS. Em estudos de Dopplerfluxometria e Dopplervelocimetria, isoladamente ou associados ao eletrocardiograma e cardiografia por impedância, foram observadas alterações na circulação hepática durante a gravidez complicada por pré?eclâmpsia e síndrome HELLP. Entre os desafios para a pesquisa nesse campo destacamos a necessidade de aperfeiçoamento da técnica de exame, o estabelecimento de curvas de normalidade para as gestantes brasileiras, de indicadores de agravamento da pré?eclâmpsia e a aplicação potencial do método para o estudo da hipertensão crônica na gravidez.(AU)

The liver is among multiple organs that may be affected in pre-eclampsia, and liver function can be impaired in HELLP syndrome. Doppler ultrasonography of the liver provides a noninvasive method to study liver circulation during pregnancy. This paper reviews scientific evidence available in MEDLINE/ Pubmed and LILACS databases. Doppler studies on hepatic blood flow, flow velocities and vascular resistance indices, isolated or combined with Doppler?electrocardiography and impedance cardiography, observed changes in pregnancies complicated by pre?eclampsia and HELLP syndrome. Challenges to this research topic include improvements in Doppler examination techniques, establishment of normal values for Brazilian pregnant women, predictors for severe pre?eclampsia and potential use of hepatic Doppler use in chronic hypertension as well.(AU)

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Aneurysms and thromboses of the portal vein are rare pathologies of the portal system that commonly follow an asymptomatic course. The vast majority of cases are diagnosed as incidental findings during imaging studies. Symptoms of aneurysms are the result of mass effects, while thrombosis symptoms are a function of the liver's ability to form a collateral circulation network in the thrombosis. The scant experience with such cases poses a dilemma for patient management and so the vast majority of authors choose an expectant approach with rigorous patient surveillance and only intervene in symptomatic patients. We report one case of an aneurysm of the portal vein and one case of portal vein thrombosis and discuss management and observation of these patients...

O aneurisma e a trombose de veia porta são doenças raras do sistema porta, que comumente cursam sem sintomas. A grande maioria dos pacientes é diagnosticada com achados em exames de imagem. Os sintomas são atribuídos ao efeito de massa, no caso do aneurisma, e relativos à capacidade hepática de formar uma rede de circulação colateral, no caso da trombose. A escassa experiência nesses casos representa um dilema na abordagem desses pacientes e, portanto, a grande maioria dos autores opta por seguimento rigoroso e a intervenção é indicada apenas para os pacientes sintomáticos. Neste trabalho, relatamos um caso de aneurisma de veia porta e outro de trombose da veia porta, propondo o manejo e o acompanhamento desses pacientes...

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BACKGROUND: Partial portal vein ligation causes an increase in portal pressure that remains stable even after the appearance of collateral circulation, with functional adaptation to prolonged decrease in portal blood flow. AIM: To assess whether different constriction rates produced by partial ligation of the vein interfere with the results of this experimental model in rats. METHODS: Three groups of five rats each were used; in group 1 (sham-operated), dissection and measurement of portal vein diameters were performed. Portal hypertension was induced by partial portal vein ligation, reducing its size to 0.9 mm in the remaining 10 animals, regardless of the initial diameter of the veins. Five animals with portal hypertension (group 2) underwent reoperation after 15 days and the rats in group 3 after 30 days. The calculation of the constriction rate was performed using a specific mathematical formula (1 - π r 2 / π R2) x 100% and the statistical analysis with the Student t test. RESULTS: The initial diameter of the animal's portal vein was 2.06 mm, with an average constriction rate of the 55.88%; although the diameter of the veins and the constriction rate in group 2 were lower than in group 3 (2.06 mm - 55,25% and 2.08 mm - 56.51%, respectively), portal hypertension was induced in all rats and no significant macroscopic differences were found between the animals that were reoperated after 15 days and after 30 days respectively, being the shorter period considered enough for the evaluation. Comparing the initial diameter of the vein and the rate of constriction performed in groups 2 and 3, no statistic significance was found (p>0.05). CONCLUSION: Pre-hepatic portal hypertension in rat can be induced by the reduction of the portal vein diameter to 0.9 mm, regardless the initial diameter of the vein and the vessel constriction rate. .

RACIONAL: A ligadura parcial da veia porta acarreta aumento da pressão portal que se mantém estável mesmo após o aparecimento da circulação colateral, havendo adaptação funcional à diminuição prolongada do fluxo sanguíneo hepático. OBJETIVO: Avaliar se diferentes taxas de constrição produzidas por esta ligadura interferem em modelo experimental no rato. MÉTODOS: Foram utilizados três grupos de cinco animais; no grupo 1 (sham-operated) foi realizada dissecção e medida do diâmetro da veia porta. A hipertensão portal foi induzida pela ligadura parcial da veia porta, reduzindo seu calibre para 0,9 mm nos 10 animais restantes, independente do diâmetro inicial das veias. Cinco animais com hipertensão portal (grupo 2) foram reoperados após 15 dias e os ratos do grupo 3 após 30 dias. O cálculo da taxa de constrição foi realizado através de fórmula matemática específica (1 - π r2 / π R2) x 100% e a análise estatística com o teste t de Student. RESULTADOS: O diâmetro médio inicial da veia porta dos animais foi de 2,06 mm, com taxa de constrição média de 55,88%; embora o diâmetro das veias e a taxa de constrição no grupo 2 tenha sido menor que no grupo 3 (2,06 mm - 55,25% e 2,08 mm - 56,51% respectivamente), em todos conseguiu-se induzir hipertensão portal e não foram encontradas diferenças macroscópicas significativas entre os animais reoperados após 15 ou 30 dias, sendo considerado o prazo menor suficiente para avaliação. Quando comparados o diâmetro inicial da veia e a taxa de constrição realizadas nos grupos 2 e 3 não houve significância estatística (p>0,05). CONCLUSÃO: A hipertensão portal pré-hepática no rato pode ser induzida pela redução de calibre da veia porta para 0,9 mm de diâmetro, independente do diâmetro inicial da veia e da taxa de constrição a que este vaso foi submetido. .

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