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Background The “Small-for-Size” syndrome is defined as a liver failure after a liver transplant with a reduced graft or after a major hepatectomy. The later coined “Small-for-Flow” syndrome describes the same situation in liver resections but based on hemodynamic intraoperative parameters (portal pressure > 20 mmHg and/or portal flow > 250 ml/min/100 g). This focuses on the damage caused by the portal hyperafflux related to the volume of the remnant. Methods Relevant studies were reviewed using Medline, PubMed, and Springer databases. Results Portal hypertension after partial hepatectomies also leads to a higher morbidity and mortality. There are plenty of experimental studies focusing on flow rather than size. Some of them also perform different techniques to modulate the portal inflow. The deleterious effect of high posthepatectomy portal venous pressure is known, and that is why the idea of portal flow modulation during major hepatectomies in humans is increasing in everyday clinical practice. Conclusions Considering the extensive knowledge obtained with the experimental models and good results in clinical studies that analyze the “Small-for-Flow” syndrome, we believe that measuring portal flow and portal pressure during major liver resections should be performed routinely in extended liver resections. Applying these techniques, the knowledge of hepatic hemodynamics would be improved in order to advance against posthepatectomy liver failure.

Background Portal vein stenosis develops in 3.4–14% of split liver transplantation 1 – 3 and its early detection and treatment are essential to achieve long-term graft survival, 2 – 5 although the diagnostic capability of conventional modalities such as Doppler ultrasound and computed tomography is limited. 1 , 4 , 5 Methods This study used computational fluid dynamics to analyze portal vein hemodynamics in the management of post-transplant portal vein stenosis. To perform computational fluid dynamics analyses, three-dimensional portal vein model was created using computed tomographic DICOM data. The inlet flow condition was set according the flow velocity measured on Doppler ultrasonography. Finally, portal vein flow was simulated on a fluid analysis software (Software Cradle, Japan). Results An 18-month-old girl underwent liver transplantation using a left lateral graft for biliary atresia. At the post-transplant 1-week evaluation, the computational fluid dynamics streamline analysis visualized vortices and an accelerated flow with a velocity ratio < 2 around the anastomotic site. The wall shear stress analysis revealed a high wall shear stress area within the post-anastomotic portal vein. At the post-transplant 6-month evaluation, the streamline analysis illustrated the increased vortices and worsening flow acceleration to reach the proposed diagnostic criteria (velocity ratio > 3:1). 3 , 5 The pressure analysis revealed a positive pressure gradient of 3.8 mmHg across the stenotic site. Based on the findings, the patient underwent percutaneous transhepatic portal venoplasty with balloon dilation. The post-treatment analyses confirmed the improvement of a jet flow, vortices, a high wall shear stress, and a pressure gradient. Discussion The computational fluid dynamics analyses are useful for prediction, early detection, and follow-up of post-transplant portal vein stenosis and would be a promising technology in post-transplant management.

Other than location of the primary colorectal cancer (CRC), a few factors are known to influence the intrahepatic distribution of colorectal cancer liver metastases (CRLM). We aimed to assess whether the anatomy of the portal vein (PV) could influence the intrahepatic distribution of CRLM. Patients with CRLM diagnosed between January 2018 and December 2022 at two tertiary centers were included and imaging was reviewed by two radiologists independently. Intra-operator concordance was assessed according to the intraclass correlation coefficient (ICC). The influence of the diameter, angulation of the PV branches and their variations on the number and distribution of CRLM were compared using Mann-Whitney, Kruskal-Wallis, Pearson's Chi-square and Spearman's correlation tests. Two hundred patients were included. ICC was high (> 0.90, P < 0.001). Intrahepatic CRLM distribution was right-liver, left-liver unilateral and bilateral in 66 (33%), 24 (12%) and 110 patients (55%), respectively. Median number of CRLM was 3 (1-7). Type 1, 2 and 3 portal vein variations were observed in 156 (78%), 19 (9.5%) and 25 (12%) patients, respectively. CRLM unilateral or bilateral distribution was not influenced by PV anatomical variations (P = 0.13), diameter of the right (P = 0.90) or left (P = 0.50) PV branches, angulation of the right (P = 0.20) or left (P = 0.80) PV branches and was independent from primary tumor localisation (P = 0.60). No correlations were found between CRLM number and diameter (R: 0.093, P = 0.10) or angulation of the PV branches (R: 0.012, P = 0.83). PV anatomy does not seem to influence the distribution and number of CRLM.

Background/Objectives: In a previous study, we observed significantly prolonged hepatic and pulmonary first-pass transit times (TTs) for 99mTc-pertechnetate absorbed through the colorectal mucosa during per-rectal portal scintigraphy (PRPS). This decrease in radiotracer flow velocity was not seen when 99mTc-pertechnetate was administered into the spleen during trans-splenic portal scintigraphy or injected intravenously in radionuclide angiocardiography. We hypothesized that 99mTc-pertechnetate, an artificial compound, is recognized during colorectal absorption as a potentially hazardous chemical (PHC), with its hepatic and pulmonary slowdown aiding elimination. A similar sudden decrease in portal flow occurs during early metastasis of colorectal cancer (CRC), as shown by a pathological rise in the hepatic perfusion index. We aimed to study the hepatic and pulmonary vasoactive responses triggered by PHCs after they pass through the gut mucosa and evaluate the potential activation of this mechanism in early CRC metastasis. Methods: We measured transit times to determine whether hepatic and pulmonary vasoconstriction occur in response to radiotracers administered at different sites. We performed PRPS with in vivo 99mTc-labelled RBC to evaluate the liver transit time (LTT) and right heart to liver circulation time (RHLT). Liver angioscintigraphy (LAS) was used to assess RHLT following the intravenous injection of 99mTc-pertechnetate and 99mTc-HDP (hydroxyethylene-diphosphate). Lower rectum transmucosal dynamic scintigraphy (LR-TMDS) was conducted to measure RHLT of 99mTc-pertechnetate delivered into the lower rectum submucosa. LAS was performed to assess LTT for 99mTc-HDP intravenously injected and delivered to the gut mucosa via arterial flow. Results: In healthy volunteers, PRPS showed notably increased LTT, ranging from 23.5 to 25.5 s, and RHLT (between 39.5 and 42.5 s) for in vivo 99mTc-labelled RBC. Significantly lower RHLT values ranging from 9 to 13.5 were observed for 99mTc-pertechnetate and 99mTc-HDP administered intravenously during LAS, as well as for 99mTc-pertechnetate at LR–TMDS (between 12 and 15 s). The LTT assessed at LAS for 99mTc-HDP ranged from 22 to 27 s. Conclusions: An intense vasoconstriction occurs in the liver and lungs in response to substances recognized by the body as PHCs when they pass through the gut mucosa, aiding their elimination.

: Liver transplantation (LT) continues to evolve with techniques aimed at minimizing perioperative complications associated with caval and portal vein clamping. Caval-sparing approaches, such as the piggyback technique, preserve hemodynamic stability; however, portal clamping remains necessary and may trigger postreperfusion syndrome, endotoxemia, and hepatic microcirculatory disturbances. Temporary portocaval shunts (PCSs) have been developed to maintain portal flow during LT, mitigating these adverse effects and allowing for hemodynamic stability and a reduced intraoperative bleeding. : Various PCS techniques-including end-to-side, right-branch, portosaphenous, mesenterico-saphenous, iliac-venous conduit interposition, portoumbilical, and Rex-saphenous shunts-allow an individualized approach based on patient anatomy and surgical complexity. : Available evidence demonstrates that PCS improves intraoperative hemodynamic stability, reduces blood transfusion requirements, and preserves renal function, particularly in patients with high portal flow or severe portal hypertension. PCS may also shorten warm ischemia time, facilitate hepatectomy, and enhance outcomes in extended criteria donor grafts or marginal organs. Meta-analyses and randomized studies support its role in reducing intraoperative blood loss, improving early graft function, and accelerating postoperative recovery. However, the effect of PCS on long-term survival and major postoperative morbidity remains variable, likely due to heterogeneity in patient populations, donor types, and perioperative management. : Overall, PCS represents a safe and feasible adjunct in LT, offering significant hemodynamic and technical advantages. Its use should be individualized based on patient risk factors, intraoperative hemodynamics, and anticipated intraoperative challenges. PCS provides a practical strategy to preserve portal flow, minimizing intraoperative complications and facilitating the hepatectomy. However, the decision to create a PCS during LT still depends on the surgeon's preference. Postoperative outcomes and impact on long-term survival require further investigation.

The levels of Annexin A5 (Annexin V) were measured in patients with and without HCC who had liver cirrhosis. These patients were followed for 12 months to determine the incidence of PVT and to determine the role of Annexin V in the diagnosis of PVT. Our goal was to look at the value of Annexin A5, platelet count, spleen size, portal flow velocity, portal vein width, Fibrosis 4, and APRI score in these individuals to see if they might be used as PVT markers. Between March 2017 and August 2018, ninety-one HCV patients with cirrhosis with and without HCC, as well as a control group of twenty healthy people, were included in this longitudinal study at the NHTMRI. The blood anxA5 level was determined using a commercial Hyphen BioMed immunoassay using Stat Fax 4700's Microstrip Reader l. Cirrhotic patients with and without HCC who developed PVT had higher Annexin A5 scales (5.75 + 0.18), compared to cirrhotic patients who did not develop PVT (3.63 + 1.08 (P 0.001). PVT was 20% in all cirrhotic patients after a year, 15% in cirrhotic patients without HCC, and 25% in cirrhotic patients with HCC. Cirrhotic patients who had PVT throughout the follow-up period had greater AnxA5 serum levels than cirrhotic patients who did not develop PVT. In all cirrhotic patients, AnxA5 level, platelet count, spleen size, portal flow velocity, portal vein diameter, and Fibrosis 4 score might be employed as markers for PVT development.

In the past, hepatic blood flow in cows was invasively characterized to investigate different pathologies and physiological conditions. However, hepatic blood flow can be easily evaluated with transabdominal Doppler ultrasound. Sixteen healthy adult non-lactating, non-pregnant Holstein-Friesian cows were examined using B-mode and Doppler ultrasound between the right flank and 9th intercostal space to establish the best approach to the different parts of the portal and hepatic vein systems, and determine normal blood flow characteristics. The main portal vein was characterized by a turbulent, high-velocity flow due to the opposing confluence of the splenic and cranial mesenteric veins, while hepatic and caudal vena cava veins have laminar blood flow, in which the phasicity is considered mainly respiratory in origin. Reference values were determined in relation to the anatomical point of observation. In conclusion, transabdominal Doppler ultrasound of the portal system is a simple technique that allows non-invasive characterization of portal and hepatic blood haemodynamics in cows.

BackgroundPortal vein thrombosis (PVT) is an infrequent, yet potentially lethal, complication of bariatric surgery. The aim of this prospective, non-randomized, cohort study is to compare between laparoscopic sleeve gastrectomy (LSG) and laparoscopic one-anastomosis gastric bypass (LOAGB) in terms of their early postoperative effects on portal venous flow and patency.MethodsForty-nine morbidly obese patients were allocated to one of 2 groups (A or B). Group A patients underwent LSG, whereas group B patients underwent LOAGB. Portal venous Doppler ultrasound scanning was performed preoperatively and 2 weeks postoperatively in all cases, in order to assess the portal venous flow (PVF) in terms of flow direction and peak systolic velocity (PSV); as well as to assess the portal venous patency and exclude PVT. The mean change in PSV (ΔPSV) and the mean percentage change in PSV (%ΔPSV) were determined in both groups.ResultsIn all cases (group A (n = 26); group B (n = 23)), the direction of PVF was “hepatopetal” both preoperatively and 2 weeks postoperatively. The mean ΔPSV and the mean %ΔPSV were higher in LSG patients “group A” (− 0.84 cm/s and 3.25% respectively) compared with LOAGB patients “group B”(− 0.06 cm/s and 0.27% respectively); P = 0.038 and 0.039 respectively. The mean change in PSV was in the negative direction in both groups, i.e., “deceleration.” No cases of PVT were reported in the study.ConclusionsLaparoscopic sleeve gastrectomy is associated with greater reduction in portal venous peak systolic flow velocity in the early postoperative period, compared with laparoscopic one-anastomosis gastric bypass.

PurposeProximal splenic artery embolization (pSAE) has been advocated as a valuable tool to ameliorate portal hyper-perfusion (PHP). The purpose of this study was to determine the safety and efficacy of pSAE to treat refractory ascites (RA) and/or refractory hydrothorax (RH) in the setting of PHP post-liver transplant.Material and MethodsA total of 30 patients who underwent pSAE for RA and/or RH after liver transplantation (LT) between January 2007 and December 2017 were analyzed retrospectively. The patients were divided into groups according to the time frame from pSAE to clinical resolution in order to identify predictors of RA/RH response to the procedure.ResultsTwenty-four (80%) patients responded to pSAE within three months, whereas 6 (20%) still required additional treatments for RA/RH at three months post-pSAE. In all cases clinical symptoms resolved within six months. Complications after pSAE were as follows: 2 cases of splenic infarction (6.6%), one case of post-splenic embolization syndrome (3.3%), one case of hepatic artery thrombosis (3.3%) and one case of portal vein (PV) thrombosis (3.3%). Increased intraoperative PV flow volume and increased pre-pSAE PV velocity, as well as higher estimated glomerular filtration rate were associated with early RA/RH resolution.ConclusionpSAE is safe and effective in treating RA and RH due to PHP after LT. This study suggests that clinical parameters indicating more severe PHP and better kidney function are possible predictors for early response to pSAE.

Abstract The higher permeability of the venules in jejunal microcirculation to albumin contributes to the increased mesenteric lymph formation. Recently, we demonstrated that water intake induced serotonin release from enterochromaffin cells in rat jejunum, serotonin of which circulated through the portal vein into blood circulation and then increased the mesenteric lymph formation. The mode of action of serotonin remains unclear. Therefore, we aimed to clarify the mechanisms involved in the regulation of the jejunal lymph formation with permeant albumin in in vivo rat experiments. We investigated the effects of intravenous administration of serotonin or water intake on the jejunal-originated lymph volume and the concentration of albumin in the lymph in the presence or absence of L-NAME. The effects of intravenous administration of L-NAME, nicardipine, A23187, and ML-7 on the lymph formation with permeant albumin were also evaluated. Serotonin or water intake significantly increased the mesenteric lymph volume with permeant albumin in the jejunal microcirculation. The serotonin- and water intake–mediated responses were significantly reduced by the pretreatment with intravenous administration of L-NAME. Intravenous administration of L-NAME itself also decreased significantly the jejunal lymph formation. Administration of A23187 and ML-7 significantly reduced the jejunal lymph formation with permeant albumin. In contrast, administration of nicardipine significantly increased the lymph formation. In conclusion, portal venous blood flow– or serotonin-mediated NO release from venular endothelial cells plays physiologically key roles in the lymph formation in rat jejunum via the extrusion of calcium ions and inactivation of MLCK in endothelial cells.