Mesenteric Vein Research Articles

Management of portal vein thrombosis in liver transplant candidates.

Portal vein thrombosis (PVT) is a frequent event among patients with advanced liver disease, with a prevalence reaching up to 26% in those awaiting liver transplantation (LT). Extensive thrombosis affecting the mesenteric vein confluence correlates with increased morbidity and mortality post-LT, particularly when it impedes physiological anastomosis or contraindicates the LT. Current guidelines advocate for routine PVT screening in all potential liver transplant candidates and prompt treatment upon detection. The main objective in LT candidates is to facilitate physiological portal-to-portal anastomosis. Anticoagulation serves as the first-line therapy, achieving recanalization rates between 33 and 75%. Discontinuation of anticoagulation significantly heightens the risk of rethrombosis in a substantial proportion of patients and therefore, it is recommended to continue anticoagulation until LT for those awaiting LT or potential LT candidates. Nevertheless, 30-60% of patients fail to respond to anticoagulation, with PVT progression occurring in up to 14% despite anticoagulation. In such cases, TIPS placement emerges as a viable alternative to maintain portal vein patency. While the feasibility of TIPS placement diminished with the presence of portal cavernoma or chronic portal vein thrombosis, the introduction of novel interventional radiological techniques to recanalize the portal venous axis through transplenic, transmesenteric and/or transhepatic routes is revolutionizing this landscape. These advancements achieve TIPS placement and recanalization in 90-100% of patients, warranting consideration in cirrhotic patients with chronic PVT for whom LT would otherwise be contraindicated or when physiological anastomosis is not feasible.

Alloplastic Vascular Grafts for Venous Interposition in Pancreatic Surgery: Readily Available and Reliable.

To investigate patency and clinical outcomes of alloplastic and other venous interposition graft materials in pancreatic surgery. Vascular pancreatic surgery is increasingly performed for locally advanced pancreatic neoplasms. Different than other centers, we prefer to use alloplastic vascular graft materials for superior mesenteric vein and portal vein interposition in pancreatic surgery. Advantages are off-the-shelf availability at any customizable length, different diameters, and ring-enforcement but proposed concerns are their thrombogenicity and fatal complications. Patients who underwent elective pancreatic resections with mesoportal venous interposition grafts (ISGPS type 4) between 2003-2022 were identified from the institutional pancreatectomy registry. Alloplastic vascular grafts imply synthetic materials, either based on polytetrafluorethylene (PTFE) or polyethylene terephthalate (PET). Surgical details, clinicopathological, and follow-up data were analyzed. The patients were followed for graft patency by cross-sectional imaging. In this study, 201 patients with venous interposition grafts were included (23% simultaneous arterial resections). Total pancreatectomy (41%) and pancreatoduodenectomy (35%) were the most frequent procedures. Vascular graft materials were alloplastic in 180 patients (83% PTFE and 17% PET) with a median diameter of 10mm and a median length of 33mm (measurement by CT scan). Patency rates among all graft materials at 7-, 30-, and 90-days were 99%, 93%, and 87%. Alloplastic grafts demonstrated superior patency over other materials (hazard ratio 2.7, P=0.009), and PTFE reached a 1-year patency of 78%. The all-cause 90-day mortality rate was 10%. No graft infection occurred. Alloplastic venous vascular grafts are safe and readily available tools in pancreatic surgery, especially for long-segmental mesoportal venous reconstructions.

Amino Acid Transport Dynamics in the Jejunum and Ileum in Rats: A Regional and Time-Course Analysis.

Postprandially, amino acids and di/tripeptides are thought to be primarily absorbed in the proximal small intestine. However, there have been no in vivo demonstrations of regional differences in amino acid transport dynamics between the proximal and distal small intestines. We monitored plasma amino acid responses in the jejunal and ileal mesenteric veins of rats after oral administration of a diet or an amino acid mixture (Experiment 1), and in the portal vein after direct administration of the amino acid mixture into the lumen of the jejunum or ileum (Experiment 2). In experiment 1, the total and some amino acid concentrations in the jejunal mesenteric vein were slightly higher than those in the ileal mesenteric vein after oral administration of the amino acid mixture, suggesting that the ileum actively transports luminal amino acids to the basolateral side, comparable to the jejunum. In experiment 2, portal amino acid concentrations were elevated to a greater extent after direct administration of the amino acid mixture into the ileal lumen than into the jejunal lumen. These results demonstrate regional differences in amino acid transport dynamics in vivo and suggest that the ileum has a higher capacity for transporting amino acids than the jejunum. Our findings highlight the importance of the ileum in postprandial amino acid absorption and metabolism.

Controlled release of hydrogel-encapsulated mesenchymal stem cells-conditioned medium promotes functional liver regeneration after hepatectomy in metabolic dysfunction-associated steatotic liver disease

BackgroundGlobally, prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing, and there is an urgent need to develop innovative therapies that promote liver regeneration following hepatectomy for this disease. Surgical excision is a key therapeutic approach with curative potential for liver tumors. However, hepatic steatosis can lead to delayed liver regeneration and higher post-operative complication risk. Mesenchymal stem cells-conditioned medium (MSC-CM) is considered a rich source of paracrine factors that can repair tissues and restore function of damaged organs. Meanwhile, hydrogels have been widely recognized to load MSC secretome and achieve sustained release. This study aimed to evaluate the therapeutic effect of hydrogel-encapsulated MSC-CM on liver regeneration following partial hepatectomy (PHx) in a rodent model of diet-induced hepatic steatosis.MethodsMale Lewis rats were fed with a methionine and choline–deficient diet. After 3 weeks of feeding, PHx was performed and rats were randomly allocated into two groups that received hydrogel-encapsulated MSC-CM or vehicle via the intra-mesenteric space of the superior mesenteric vein (SMV).ResultsThe regeneration of the remnant liver at 30 and 168 h after PHx was significantly accelerated, and the expressions of proliferating cell nuclear antigen were significantly enhanced in the MSC-CM group. MSC-CM treatment significantly increased hepatic ATP and β-hydroxybutyrate content at 168 h after PHx, indicating that MSC-CM fosters regeneration not only in volume but also in functionality. The number of each TUNEL- and cleaved caspase-3 positive nuclei in hepatocytes at 9 h after PHx were significantly decreased in the MSC-CM group, suggesting that MSC-CM suppressed apoptosis. MSC-CM increased serum immunoregulatory cytokine interleukin-10 and interleukin-13 at 30 h after PHx. Additionally, mitotic figures and cyclin D1 expression decreased and hepatocyte size increased in the MSC-CM group, implying that this mode of regeneration was mainly through cell hypertrophy rather than cell division.ConclusionsMSC-CM represents a novel therapeutic approach for patients with MASLD requiring PHx.

Imaging of the Inferior Mesenteric Vasculature.

The inferior mesenteric artery (IMA) and inferior mesenteric vein (IMV) supply and drain blood from the distal colon and rectum, respectively. Routinely imaged at cross-sectional imaging of the abdomen and pelvis, these vessels play a vital role in gastrointestinal tract health but may be neglected due to their diminutive caliber relative to other mesenteric vessels and potential lack of inclusion in routine search patterns. The authors describe and illustrate normal and abnormal appearances of the IMA and IMV and findings that are diagnostic of primary vascular abnormalities or can offer diagnostic clues. After the embryologic features, normal anatomy, and anatomic variants of the IMA and IMV are reviewed, various manifestations of IMA and IMV abnormalities, such as aneurysm and pseudoaneurysm, stenosis, occlusion, dissection, hemorrhage, arteriovenous malformations and fistulas, tumoral invasion, vasculitis, and perivascular lymphatic dilatation, are explored with use of case examples. The role of the IMA and IMV as collateral vasculature, including the clinical scenarios of superior mesenteric arterial occlusion, aortic endoleak, and portosystemic venous shunt, are discussed. Finally, diagnostic clues that the inferior mesenteric vessels and adjacent soft tissues can provide, including mesenteric venous gas, compression or displacement from bowel volvulus or internal hernias, lymphadenopathy, and venous flow artifacts, are highlighted. The authors provide a comprehensive reference for radiologists who evaluate the IMA and IMV on cross-sectional images and shine a spotlight on these neglected but important vessels. ©RSNA, 2024 Supplemental material is available for this article.

A Study on Lymph Node Distribution in the Main Lymph Node Area for Left-sided Colon Cancer.

In advanced left-sided colorectal cancer, cutting the root of the inferior mesenteric artery (IMA) branching from the aorta is recommended for complete lymph node dissection. However, this procedure sometimes causes severe complications. This study aimed to elucidate the lymph nodes' distribution around the IMA and identify the most critical sites for lymph node dissection. This study included 30 consecutive patients with left-sided colorectal cancer who underwent curative resection with main lymph node dissection in a single institution between January and June of 2022. The mesenteric sections (main lymph nodes, IMA, left colic artery [LCA], and inferior mesenteric vein) were removed from the surgically excised specimen. Subsequently, whole-tissue sections were prepared and stained with hematoxylin and eosin. The positional relationships between each blood vessel and respective lymph nodes were then assessed using the pathological findings. The main lymph nodes were identified in 26 out of 30 patients. The total number of dissected lymph nodes per patient was 0-30 (average: 5.3), and the median distance from the IMA to the main lymph node was 7.61 mm (1.87-43.26 mm). Dividing the lymph nodes into segments, we found 18%, 46%, and 36% of the lymph nodes in the proximal, middle, and distal segments, respectively. Additionally, all lymph nodes were found outside of the IMA sheath surrounding each arterial wall. In left-sided colorectal cancer, the main lymph nodes are mostly located around the LCA bifurcation, which may be essential to ensure main lymph node dissection for advanced stage cases.

The endocannabinoid system in bovine tissues: characterization of transcript abundance in the growing Holstein steer

BackgroundThe endocannabinoid system (ECS) is highly integrated with seemingly all physiological and pathophysiological processes in the body. There is increasing interest in utilizing bioactive plant compounds, for promoting health and improving production in livestock. Given the established interaction between phytochemicals and the ECS, there are many opportunities for identification and development of therapies to address a range of diseases and disorders. However, the ECS has not been thoroughly characterized in cattle, especially in the gastrointestinal tract. The objective of this study was to characterize the distribution and transcriptional abundance of genes associated with the endocannabinoid system in bovine tissues.MethodsTissues including brain, spleen, thyroid, lung, liver, kidney, mesenteric vein, tongue, sublingual mucosa, rumen, omasum, duodenum, jejunum, ileum and colon were collected from 10-mo old Holstein steers (n = 6). Total RNA was extracted and gene expression was measured using absolute quantification real time qPCR. Gene expression of endocannabinoid receptors CNR1 and CNR2, synthesis enzymes DAGLA, DAGLB and NAPEPLD, degradation enzymes MGLL and FAAH, and transient receptor potential vanilloids TRPV3 and TRPV6 was measured. Data were analyzed in R using a Kruskal-Wallis followed by a Wilcoxon rank-sum test. Results are reported as the median copy number/20 ng of equivalent cDNA (CN) with interquartile range (IQR).ResultsThe greatest expression of CNR1 and CNR2 was in the brain and spleen, respectively. Expression of either receptor was not detected in any gastrointestinal tissues, however there was a tendency (P = 0.095) for CNR2 to be expressed above background in rumen. Expression of endocannabinoid synthesis and degradation enzymes varied greatly across tissues. Brain tissue had the greatest DAGLA expression at 641 CN (IQR 52; P ≤ 0.05). DAGLB was detected in all tissues, with brain and spleen having the greatest expression (P ≤ 0.05). Expression of NAPEPLD in the gastrointestinal tract was lowest in tongue and sublingual mucosal. There was no difference in expression of NAPEPLD between hindgut tissues, however these tissues collectively had 592% greater expression than rumen and omasum (P ≤ 0.05). While MGLL was found to be expressed in all tissues, expression of FAAH was only above the limit of detection in brain, liver, kidney, jejunum and ileum. TRPV3 was expressed above background in tongue, rumen, omasum and colon. Although not different from each other, thyroid and duodenum had the greatest expression of TRPV6, with 285 (IQR 164) and 563 (IQR 467) CN compared to all other tissues (P < 0.05).ConclusionsThese data demonstrate the complex distribution and variation of the ECS in bovine tissues. Expression patterns suggest that regulatory functions of this system are tissue dependent, providing initial insight into potential target tissues for manipulation of the ECS.

Deep learning-based surgical step recognition for laparoscopic right-sided colectomy.

Understanding the complex anatomy and surgical steps involved in laparoscopic right-sided colectomy (LAP-RC) is essential for standardizing the surgical procedure. Deep-learning (DL)-based computer vision can achieve this. This study aimed to develop a step recognition model for LAP-RC using a dataset of surgical videos with annotated step information and evaluate its recognition performance. This single-center retrospective study utilized a video dataset of laparoscopic ileocecal resection (LAP-ICR) and laparoscopic right-sided hemicolectomy (LAP-RHC) for right-sided colon cancer performed between January 2018 and March 2022. The videos were split into still images, which were divided into training, validation, and test sets using 66%, 17%, and 17% of the data, respectively. Videos were manually classified into eight main steps: 1) medial mobilization, 2) central vascular ligation, 3) dissection of the superior mesenteric vein, 4) retroperitoneal mobilization, 5) lateral mobilization, 6) cranial mobilization, 7) mesocolon resection, and 8) intracorporeal anastomosis. In a simpler version, consecutive surgical steps were combined, resulting in five steps. Precision, recall, F1 scores, and overall accuracy were assessed to evaluate the model's performance in the surgical step classification task. Seventy-eight patients were included; LAP-ICR and LAP-RHC were performed in 35 (44%) and 44 (56%) patients, respectively. The overall accuracy was 72.1% and 82.9% for the eight-step and combined five-step classification tasks, respectively. The automatic surgical step-recognition model for LAP-RCs, developed using a DL algorithm, exhibited a fairly high classification performance. A model that understands the complex steps of LAP-RC will aid the standardization of the surgical procedure.

Anatomical variants of the jejunal veins and their technical implications in pancreaticoduodenectomy: a systematic review and meta-analysis.

One of the most common causes of bleeding during pancreaticoduodenectomy (PD) is dissection of the pancreatic head from the superior mesenteric vein (SMV) and superior mesenteric artery (SMA). Knowledge of the anatomical variants of the veins draining the proximal jejunum may allow a better control of bleeding during detachment of the uncinate process and pancreatic head from the mesenteric pedicle and division of the mesopancreas. The aim of this systematic review and meta-analysis is to evaluate the anatomical variations of the first jejunal vein (FJV) and jejunal trunk (FJT). Fourteen studies (1,888 patients) were included. We performed a systematic review of the available Literature according to the PRISMA guidelines. The analysis has shown that the posterior course of the FJT and FJV represents the most frequent topographical location (PPE 79.6%) with the anterior jejunal trunk (JT) having a lower rate (PPE 20.4%). Few articles reported the variations with separate trunks for the first and second jejunal vein. A thorough preoperative radiological assessment of the anatomical variation of FJT and FJV may confer some advantage to establish the best therapeutic strategy and the best surgical approach in case of pancreatic head carcinoma, as it can allow a better estimate of the extent of the neoplasm and improve the accuracy of surgical dissection with potential for reduced bleeding.

Mesenteric Vein to Gonadal Vein Shunt Embolization in Patients with Portal Hypertension: Technical Considerations and Clinical Outcomes.

To assess the technical and clinical outcomes of percutaneous embolization for high-flow mesenteric vein to gonadal vein (MGV) portosystemic shunts. In this HIPPA-compliant, review board-approved study, patients who underwent embolization of MGV shunts between 2011 and 2023 were included. Patient demographic data, embolization technique, clinical outcomes, and complications were retrieved from the electronic health records. Technical success was defined as complete occlusion of the shunt on follow-up imaging. Clinical outcomes assessed were resolution/improvement of hepatic encephalopathy, improvement in liver function, changes to liver volumes, and occurrence of adverse events. Eight patients (mean age 59.5, 75% female) with nine MGV shunts were included. The indications for shunt embolization included medically refractory hepatic encephalopathy, bleeding duodenal varices, and transplant liver dysfunction. The mean maximum shunt diameter was 23.3mm. Embolization was most commonly performed with a combination of coils and N-butyl cyanoacrylate or vascular plugs. Complete MGV shunt thrombosis was achieved in 7/9 shunts post-embolization, and symptom improvement was noted in 7/8 patients. Child-Pugh scores improved post-embolization in 6/9 patients by a median of 3 points. Liver volumes also increased by a mean of 20.8 ± 17.7% post-embolization. Minor adverse events included new onset ascites, partial mesenteric/portal vein thrombosis, and new gastroesophageal varices without bleeding in four patients. Embolization of MGV shunts is technically feasible and effective for treatment of hepatic encephalopathy and increasing hepatopetal portal perfusion. There was an improvement in Child-Pugh scores and an increase in liver volumes in the majority of patients post-embolization.

Myointimal hyperplasia of the mesenteric veins mimicking inflammatory bowel disease in a 13‐year‐old patient

AbstractIdiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare entity reported in adults, frequently mimicking inflammatory bowel disease (IBD). We report the first case of intestinal ischemia secondary to IMHMV presenting as IBD in a pediatric patient with Down syndrome. Chronic intestinal ischemia is rare in children, and this case emphasizes the need to consider this in the differential, when histopathology is suggestive. Clinical findings and colonoscopy in these patients may mimic IBD. The mucosal biopsies do not show classic features of IBD. Instead, there can be variable extent of mucosal changes such as dilated small capillaries in the lamina propria, edema, and early fibrosis. These changes may in fact represent early chronic ischemia. These findings should alert for vascular imaging and a full‐thickness biopsy to assess submucosal and subserosal larger vessels since medium‐ and large‐caliber veins in the colonic wall and mesentery are affected in IMHMV.

Intraoperative indocyanine green fluorescence for precise resection of nonocclusive mesenteric ischemia: a case report and diagnostic considerations based on pathology findings

BackgroundNonocclusive mesenteric ischemia (NOMI) is characterized by intestinal ischemia caused by spasms in the peripheral intestinal vessels without organic obstruction in the main mesenteric vessels. NOMI can be fatal in case of delayed diagnosis and treatment. Although the use of indocyanine green (ICG) fluorescence in assessing intestinal viability during NOMI surgery is well recognized, there is a paucity of reported cases using this technique. Herein, we present a case of NOMI that was successfully managed through accurate diagnosis and resection of the ischemic intestines guided by ICG fluorescence.Case presentationAn 81-year-old man presented with abdominal pain. Contrast-enhanced computed tomography revealed intrahepatic portal vein gas, superior mesenteric vein gas, and terminal ileal edema. Considering these findings, the patient was diagnosed with NOMI and emergency surgery was performed. Intestinal edema was observed 30 cm upstream of the terminal ileum without serosal discoloration. ICG fluorescence revealed areas of normal perfusion as well as mild and moderate hypoperfusion. The small bowel, including the hypoperfusion area, was resected. As no clinical signs of residual bowel ischemia were observed during the postoperative course, a second-look operation was deemed unnecessary. Intraoperative ICG fluorescence and histopathological findings indicated mucosal edema in the mildly hypoperfused area and mucosal necrosis in the moderately hypoperfused area.ConclusionsThis case highlights the use of intraoperative ICG fluorescence in the disease. ICG fluorescence is invaluable in assessing the extent of bowel ischemia and guiding precise resection. Thus, future efforts should focus on identifying accumulation of cases and quantification of ICG fluorescence intensity to further improve diagnostic performance.

Engineering Hyperechogenic Colloids with Clot-Targeting Capabilities from Platelet-Derived Membranes.

Thrombosis-related cardiovascular diseases remain the leading global cause of mortality and morbidity. In this study, we present a pioneering approach in the field of nanobiotechnology, with a focus on clinical translation, aimed at advancing early diagnosis and enhancing treatment options for thrombotic disorders. We introduce the fabrication of Platelet Membrane-Derived Bubbles (PMBs), which exhibit distinctive characteristics compared to conventional nanoparticles. These PMBs possess an average diameter of 700 nm and a negative ζ-potential, mirroring the attributes of parent platelet membranes. Utilizing diagnostic ultrasound imaging, we demonstrated the ability to visualize PMBs as hyperechogenic entities in agarose phantoms in vitro and in live mice in vivo. Furthermore, through confocal laser microscopy, we verified the retention of crucial transmembrane proteins, such as CD41 (GPIIb) and CD42 (GPIb), pivotal in conferring platelet-specific targeting functions. Importantly, our platelet aggregation studies confirmed that PMBs do not induce platelet aggregation but instead adhere to preformed platelet-rich in vitro thrombi. Overall, our work showcases the safe and precise utilization of PMBs to directly target acute thrombosis induced by laser injury in murine mesenteric veins in vivo, as visualized through intravital microscopy. In conclusion, we have successfully developed a rapid method for generating PMBs with unique ultrasound-directed and thrombus-targeting properties. These exceptional attributes of PMBs hold significant promise for advancing the field of ultrasound diagnostic thrombus imaging and clot-targeted therapy in the clinical context.

Clinical application of inferior pancreaticoduodenal artery management in laparoscopic pancreaticoduodenectomy

Objective: To investigate the clinical effect of proper management of inferior pancreaticoduodenal artery (IPDA) in laparoscopic pancreaticoduodenectomy (LPD). Methods: This is a retrospective case series study. The clinical and pathological data of 70 patients who received LPD due to pancreatic head tumors, periampullary tumors, or distal common bile duct tumors in the Pancreatic Center of the Second Clinical College of Guangzhou University of Chinese Medicine from January to December 2022 were retrospectively collected. There were 47 males(67.1%) and 23 females(32.9%),aged (59.9±12.8)years(range:13 to 87 years).The procedure of IPDA exposure was as follows:a middle approach was utilized to expose the right half of superior mesenteric artery(SMA) and its right branches between the SMA and superior mesenteric vein(SMV) in superior colonic region. In the subcolonic region,SMA trunk exposure via dissection along the jejunal artery from feet to head and identification the association between IPDA and jejunal artery were prior to IPDA root ligation and dissection. The safety and efficacy of intraoperative IPDA handling were assessed based on surgical videos. Follow-up was carried out in outpatient clinic or by telephone, and outpatient follow-up was conducted once every 1 to 3 months after surgery. Results: The percentage of total LPD was 98.6%(69/70),with all patients achieving R0 resection. Nine cases(12.9%) were involved in combined vascular resection and reconstruction,with 1 case (1.4%) requiring additional upper abdominal incision for vascular and gastrointestinal reconstruction,while the remaining eight cases (11.4%) were completed laparoscopically. The operative time was (432.7±115.4)minutes(range:282 to 727 minutes), and the blood loss was (140.0±125.7)ml(range:20 to 800 ml). Only two patients(2.9%) received fresh frozen plasma transfusion,with an average volume of 650 ml. Reliable ligation and safe handling of the IPDA were achieved in 91.4%(64/70) of cases, with 8.6%(6/70) suffering from IPDA injury-related bleeding. No one was converted to opened surgery. Pathologically,the mean tumor size was (3.3±1.6)cm (range:1 to 7 cm),and the mean number of harvested lymph nodes was 17.0±7.3(range:0 to 46). Lymph node metastasis was observed in 13 cases (18.6%). Five cases (13.2%) developed grade B pancreatic fistula,while no grade C pancreatic fistula occurred. Other complications included bile leakage in one case(1.4%),delayed gastric emptying in two cases(2.9%), lymphatic leakage in 2 cases(2.9%),intra-abdominal infection in 9 cases(12.9%),and fat liquefaction of surgical incision in 1 case(1.4%). Two cases(2.9%) experienced postoperative intra-abdominal bleeding,one due to mesangial bleeding of lesser curvature of the stomach and the other due to oozing from the hepatic arterial sheath. These bleeding events were not concerned with IPDA. The average length of postoperative hospital stay was (15.2±4.6)days(range:9 to 28 days). Conclusion: Proper intraoperative management of IPDA in LPD might reduce IPDA-related bleeding during and after surgery and improve the safety of LPD.

Evaluation of the presence and severity of spontaneous splenorenal or gastrorenal shunts via four-dimensional flow magnetic resonance imaging: a preliminary study.

Four-dimensional phase-contrast magnetic resonance imaging (4D flow MRI) is a relatively new type of MRI acquisition technique that provides a unique and comprehensive set of information within a single acquisition, including hemodynamic and anatomical information. This study was designed to noninvasively evaluate the correlation between the presence and severity of spontaneous splenorenal shunt (SRS) or gastrorenal shunt (GRS) and 4D flow MRI-derived parameters. This retrospective case-control study enrolled 70 patients who were diagnosed with hepatocirrhosis portal hypertension and admitted to the Second Affiliated Hospital of Chongqing Medical University. Patients were divided into three groups according to the diameter of the SRS and GRS. 4D flow MRI-derived parameters, including the turbulent kinetic energy, total volume (TV), flow velocity, blood flow volume (BFV), maximum flow (MF), wall shear stress, and relative pressure, were obtained for eight cut planes: proximal to the splenomesenteric confluence and liver hilum of the portal vein (PV1/PV2); the left/right branch of the bifurcation of the PV (LPV/RPV), at the mesosplenic confluence of the splenic vein (SV1), at the splenic hilum of the SV (SV2); at the proximal to the splenomesenteric confluence of the superior mesenteric vein (SMV1), and 5 cm from the splenomesenteric confluence of the SMV (SMV2). Comparisons among the three groups were based on one-way analysis of variance (ANOVA). Logistic regression was used to identify the risk factors for small SRS/GRS (S-SRS/GRS) and for large SRS/GRS (L-SRS/GRS). Receiver operating characteristic curves were used to evaluate the diagnostic performance of the independent risk factors for SRS and GRS. The associations between the clinical data and the 4D flow MRI-derived parameters of GRS and SRS were assessed via Spearman correlation coefficient analysis. The presence of SRS or GRS was correlated with TVLPV (r=-0.302; P=0.035), TVPV1 (r=-0.385; P=0.001), TVPV2 (r=-0.301; P=0.013), BFVPV1 (r=-0.360; P=0.010), BFVSMV2 (r=0.371; P=0.008), MFPV1 (r=-0.341; P=0.004), and MFPV2 (r=-0.291; P=0.017). Meanwhile, the severity of the SRS or GRS was correlated with alanine aminotransferase level (r=-0.535; P<0.001), BFVLPV (r=-0.560; P=0.008), aspartate aminotransferase level (r=-0.321; P=0.038), and model for end-stage liver disease score (r=0.323; P=0.039). TVPV1, TVPV2, BFVPV1, BFVPV2, and MFSMV2 were found to be independent risk factors for L-SRS/GRS, with intermediate diagnostic efficacy, with the area under the curve (AUC)TV PV1=0.706 [95% confidence interval (CI): 0.519-0.853; sensitivity, 61.54%; specificity, 80.77%; P=0.018], AUCBFV PV1 =0.694 (95% CI: 0.507-0.844; sensitivity, 95.00%; specificity, 63.16%; P=0.035), AUCTV PV2 =0.729 (95% CI: 0.544-0.870; sensitivity, 77.78%; specificity, 66.67%; P=0.016), AUCBFV PV2 =0.718 (95% CI: 0.531-0.862; sensitivity, 60.00%; specificity, 82.35%; P=0.017), and AUCMF SMV2 =0.788 (95% CI: 0.608-0.912; sensitivity, 44.00%; specificity, 84.46%; P=0.005), respectively. As the TV of PV1 and PV2 and the BFV of PV1 and PV2 decreased, the risk of L-SRS/GRS increased. As the MF of SMV2 increased, the risk of the presence of L-SRS/GRS increased. 4D flow MRI-derived parameters correlated with the presence and severity of SRS or GRS. Meanwhile, the independent risk factors for the presence of L-SRS/GRS were the TV of LPV, PV1, and PV2; the BFV of PV1 and SMV2; and the MF of PV1 and PV2.

Thrombosis and anticoagulation after portal vein reconstruction during pancreatic surgery – A systematic review

ObjectiveTo comprehensively assess thrombotic events and their clinical impact in patients receiving pancreatic surgery with venous resection and reconstruction. BackgroundPortal vein (PV, including the portal vein and superior mesenteric vein) resection and reconstruction enables surgical removal of borderline-resectable and locally advanced pancreatic cancer. Thrombosis of the reconstructed PV represents a major source of early postoperative and long-term morbidity and mortality. No universally accepted standard for anticoagulation exists. Here, we aimed to assess early and late thrombosis rates after PV reconstruction with special regard to type of PV reconstruction as well as anticoagulation regimen. MethodsPRISMA guidelines were followed. Studies reporting on PV resection and reconstruction providing data on thrombosis rates were included. The following parameters were assessed: Study type, year of publication, number of patients, type/number of PV reconstruction, follow-up period, postoperative mortality, rate of thrombosis of reconstructed PV axis, intraoperative blood loss, and anticoagulation. Results23 studies with 2751 patients were included in the final analysis. 670 patients received tangential resection of the PV with venorrhaphy or patch repair, 1505 patients had segmental resection with end-to-end reconstruction, and 576 patients received reconstruction with an interposition graft/conduit. The pooled overall thrombosis rate was 15%. Reconstruction of tangential defects with either venorrhaphy or patch repair as well as end-to-end repair of segmental defects resulted in a thrombosis rate of 12%. Subgroup analysis according to the type of graft reconstruction revealed the highest occlusion rates of 55% in patients with allogeneic grafts, followed by up to 27% in patients with synthetic PV conduits. Autologous conduits had a thrombosis rate of 10%. Early thrombotic events were detected in 5% of patients after venorrhaphy/patch reconstruction and end-to-end reconstruction. Early events were most common in the allogeneic graft subgroup (22%), followed by synthetic conduits (15%). There were fewer early events in the autologous graft group (7%). Early PV thrombosis was associated with relevant mortality of up to 26%. Anticoagulation regimens varied between studies. ConclusionThe overall rate of thrombosis after portal vein resection is low. However, among different reconstruction techniques, allogeneic interposition grafts/conduits had the highest thrombosis rates among the different types of reconstruction after PV resection. No specific anticoagulation strategy can be considered beneficial on the basis of the existing literature. Mini-AbstractThrombosis of the reconstructed portal vein (PV) after PV resection in pancreatic surgery represents a relevant source of major morbidity and mortality. In this systematic review, while we observed an overall low thrombosis rate following PV resection, reconstruction with allogeneic grafts harbors the highest risk of postoperative thrombosis. Early thrombosis was most common after reconstruction with allogeneic grafts and associated with postoperative mortality. Anticoagulation strategies vary greatly among different studies.

Porto-mesenteric four-dimensional flow MRI: a novel non-invasive technique for assessment of gastro-oesophageal varices

ObjectivesTo assess the role of 4D flow MRI in the assessment of gastro-oesophageal varices and in the prediction of high-risk varices in patients with chronic liver disease.MethodsThirty-eight patients diagnosed with either oesophageal or gastric varices were included in this single-centre prospective study. 4D flow MRI was used to calculate peak flow, average flow and peak velocity at the portal vein confluence (PV1) and hilum (PV2), splenic vein hilum (SV1) and confluence (SV2), and superior mesenteric vein (SMV). PV and SV fractional flow changes were also measured.ResultsROC analysis revealed that both PV2 average flow and PV fractional average flow change had 100% sensitivity to predict high-risk patients with the PV fractional peak flow change having the widest area under the curve (AUC) and the highest specificity (92.3%). SV1 average flow, SV2 average flow, SV2 peak flow, and SV2 peak velocity increased significantly in patients with oesophageal compared to gastric varices included (p = 0.022, < 0.001, < 0.001 and 0.001, respectively).ConclusionBased on certain porto-mesenteric blood flow, velocity, and fractional flow change parameters, 4D flow MRI showed excellent performance in identifying high-risk patients and giving an idea about the grade and location of varices.Critical relevance statementVariceal bleeding is a major consequence of unidentified risky upper GI varices. Thus, by identifying and locating high-risk varices early, either oesophageal or gastric, using a non-invasive method like MRI, adverse events might be avoided.Key Points4D flow MRI can be used as a potential alternative for endoscopy to predict patients with high-risk varices.Based on portal vein fractional flow change, splenic flow and velocity, 4D MRI can predict and locate high-risk varices.Earlier identification of high-risk varices can allow for interventions to prevent adverse events.Graphical

Robot-Assisted Pancreaticoduodenectomy Using the Anterior Superior Mesenteric Artery-First Approach for Pancreatic Cancer

BackgroundThe superior mesenteric artery (SMA)-first approach for pancreatic cancer (PC) is common surgical technique in pancreaticoduodenectomy. To date, few studies have reported SMA-first approach in robot-assisted pancreaticoduodenectomy (RPD). Herein, we present the anterior SMA-first approach for PC during RPD.Patient and MethodA 75-year-old man with resectable PC underwent RPD after neoadjuvant chemotherapy. As pancreatic head tumor contacted with the superior mesenteric vein (SMV), the anterior SMA approach was applied. After the mesenteric Kocher maneuver, the jejunum was divided and the left side of the SMA was dissected. Subsequently, the anterior plane of the SMA was dissected. Following the division of branches from the mesenteric vessels, the SMA was taped, and the circumferential dissection around the SMA was performed to detach the pancreatic neck from the SMA completely. Finally, the dissection between the SMV and the tumor was performed under vascular control to remove the specimen.ConclusionsThe anterior SMA-first approach can be optional in patients with PC undergoing RPD. This unique approach allows for the circumferential dissection around the SMA during RPD.

Clinical outcomes of preservation versus resection of portal/superior mesenteric vein during pancreaticoduodenectomy in pancreatic cancer patients who respond to neoadjuvant treatment: A retrospective cohort study

Background: R0 rates have increased as neoadjuvant treatment (NAT) has become the primary treatment for pancreatic ductal adenocarcinoma (PDAC) with venous involvement, suggesting a decrease in venous tumor infiltration. The aim of this study was to investigate the clinical outcomes of preserving the portal/superior mesenteric vein (PV/SMV) during pancreaticoduodenectomy (PD) in PDAC patients who underwent NAT. Material and Methods: The 113 patients with resectable and borderline resectable PDAC with venous involvement who responded to NAT and underwent curative PD between 2012 and 2022 were retrospectively reviewed. Results: Among the 113 patients, PV/SMV preservation (PVP) was performed in 68 patients (60.2%), and PV/SMV resection (PVR) was performed in 45 patients (39.8%). There was no significant difference in the R0 rate, 5-year overall survival (OS) and recurrence-free survival between the two groups. PV/SMV stenosis within 3 months after surgery was more common in the PVR group than in the PVP group (1.5% versus 22.2%; P &lt; 0.001), and 5-year PV/SMV stenosis-free survival was significantly higher in the PVP group than in the PVR group (76.5% versus 53.4%; P=0.014). Multivariate analysis showed that gemcitabine-based neoadjuvant chemotherapy was associated with poor OS. PVR, clinically relevant postoperative pancreatic fistula, and locoregional recurrence were independent risk factors for PV/SMV stenosis. Conclusion: The PVP group had similar oncologic outcomes and better vessel-functional outcomes than the PVR group. Therefore, if dissection is possible and there is a high likelihood of achieving R0 resection after NAT, routine PVR may be unnecessary in PDAC patients with venous involvement.

Computed tomography in quality control of surgery for right colon cancer

AIM: to assess the length of the stump of the feeding arteries of the right colon, their anatomical location relative to the superior mesenteric vein (SMV), the level of ligation of the main arteries after right hemicolectomy with D2- and D3-lymphadenectomy. PATIENTS AND METHODS: the retrospective study included 82 patients with a histologically confirmed right colon cancer aged 44-88 (mean 68) years. All patients underwent right hemicolectomy. In 40 cases, D2 lymph node dissection was performed, in 42 cases — in D3. Preoperatively, all patients were assessed for the location of the ileocolic and right colon arteries relative to the SMV and the expected length of their stumps was measured by CT. Postoperatively, the actual length of the stumps was assessed. RESULTS: CT images of the ileocolic artery stump were obtained in 76 (92.6%) of 82 patients. In 6 patients, a metal clips were installed along the contour of the superior mesenteric artery; in such cases, a clear CT image of the stump of the ileocolic artery was not obtained, and the length of the stump was assessed as 0 mm. The stump of the right colic artery was determined in all patients in whom the artery was identified preoperatively. The ventral location of the ileocolic artery relative to the SMV according to CT data was identified in 38 (46.3 %) of 82 patients, the dorsal location — in 44 (53.7 %) of 82 patients. With the ventral location of the ileocolic artery relative to the SMV in patients with D2, the length of the artery was 14.3 (8-25.6) mm, with D3 — 7.6 (3.3–11.1) mm (p = 0.005). With the dorsal location of the ileocolic artery relative to the SMV in patients with D2, the length of the artery was 8.8 (4.9–16.2) mm, with D3 — 3.9 (1–6.9) mm (p = 0.004). CONCLUSION: the actual length of the stump of the feeding artery can become an indicator of the level of ligation of the main arteries and, indirectly, the extent of lymphadenectomy after right hemicolectomy. Further studies with a larger number of cases are needed to confirm the hypothesis for measuring the length of the stump of the feeding arteries as a marker of the extent of the procedure performed.