Background: Patients with myeloproliferative neoplasms (MPN) are at increased risk of splanchnic vein thrombosis (SVT), defined as abdominal thrombosis in portal, splenic, mesenteric or hepatic veins. MPN-SVT carries a significant mortality and morbidity burden and poses clinical management challenges. Detailed studies of this patient population are lacking. Aims: To establish a national web-based clinical registry for MPN-SVT (MASCOT Registry) and use this to investigate demographics, clinical features, co-morbidities, outcome & UK treatment practices for MPN-SVT. Methods: The MASCOT Registry is a UK-wide retrospective cohort of patients with MPN-SVT from 9 large haematology/hepatology centres. Participating centres entered pseudo-anonymised data for patients with MPN-SVT. New and historical cases were added; demographic, radiologic, clinical and outcome data were collected. Results: 232 patients with MPN-SVT were registered on the online database between May 2019 and January 2022. 1 centre registered 92 cases (40%) and 2 centres each registered 39 cases (17%) with the remaining 62 cases (27%) from 6 centres. 57% of patients were female and 43% male and the age of SVT onset was 49 years or less in 70% of patients. Median follow up was 7.3 years (range 35 days-31.8 years). SVT was diagnosed in 2009 or later in 72%. MPN was diagnosed first in 30% of patients, SVT first in 42% of patients and simultaneous diagnosis in 28%. Figure 1 shows the subtypes of MPN associated with SVT. Multiple splanchnic vein thromboses were observed in 42% of patients. Of those with single vein thrombosis, the portal vein was affected in 26% and the hepatic vein in 23%. Initial anticoagulation treatment was in line with local policy. TIPSS (transjugular intrahepatic portosystemic shunt) was performed in 21% and thrombolysis in 7%. Warfarin only was the preferred long-term anticoagulant (53%). Cytoreduction at registration comprised 44% of patients on hydroxycarbamide, 18% on Pegylated interferon, 16% on ruxolitinib and 8% on no therapy. 37 patients required major abdominal surgery and 17 received liver transplants. 71 patients (33%) suffered from other non-SVT thromboses (34% pre-SVT, 9% simultaneously and 57% post-SVT), comprising 84 thrombotic events (60 venous, 24 arterial). Grade 3+ haemorrhage was observed in 60 patients (28%), of which the majority (48%) occurred within the first year of SVT diagnosis. 111 patients (51%) were re-imaged at least once within 12 months post-SVT, demonstrating clot extension in 12%, recanalization in 25% and stable appearances in 54%. Overall survival was 88% with 14 deaths, of which 6 were disease-related. Median age at death was 72 years and death occurred at a median of 12 years post SVT diagnosis. Image:Summary/Conclusion: This is one of the largest cohort studies of patients with MPN-SVT to date with over 70% diagnosed in the last 13 years. Similar to previous published studies, our evidence corroborates the female predominance and relatively young age at diagnosis. Our data highlight the significant morbidity and mortality burden incurred by patients with MPN-SVT, including a substantially lower rate of re-canalisation compared to a recent meta-analysis of all patients with SVT and high rates of thrombosis recurrence. We have highlighted variations in clinical practice including choice of anticoagulant, preferred cytoreductive agent and use of thrombolysis and TIPSS. Future studies to further understand this patient population should be focused on access to optimal care, the aetiology of thrombosis, optimum anticoagulation management and strategies to minimise bleeding.

Background: Splanchnic vein thrombosis (SVT) is strongly associated with Myeloproliferative neoplasms (MPN) and isolated JAK2v617f mutation. MPN-SVT is associated with significant disease-related and iatrogenic complications. Patients’ service needs are therefore complex. Aims: To assess the resource implications in MPN-SVT patients at a tertiary London hospital. Methods: MPN-SVT was defined as thrombosis of the portal (PVT), hepatic (BCS), superior mesenteric (SMVT), splenic (SpT) vein singly or in combination plus a diagnosis of MPN including: Polycythaemia Vera (PV), Essential Thrombocythaemia (ET), Myelofibrosis (MF), MPN unclassified (MPNu), Myelodysplastic syndrome-MPN (MDS-MPN) or isolated JAK2v617f mutation. 67 patients were identified from an existing database of patients, 16 excluded due to incomplete records. 51 patients were followed for a median of 5 years (range 1–25). Data was collected through the IT systems at our hospital and shared cared hospitals. Patients were treated to standard algorithm1. Resources analysed: imaging (CT, MRI, US), procedures (endoscopy, bone marrow (BM) biopsy, interventions) and treatment (anticoagulation, aspirin, cytoreductive agents). Clinical outcomes and overall QOL were also recorded. Results: 52% were female, 48% male. Median age at SVT diagnosis: 42 (range 16–71). 16 had PV, 12 MF, 11 ET, 7 isolated JAK2v617f, 5 other. SVT at presentation: 41% isolated PVT, 27% BCS, 26% combined PVT and 6% isolated SpT. Median number of scans related to diagnosis: 8 (range 1–39) (Table 1). Median of 4 CT scans (0–19), 4 US (0–21) and 1 (0–18) MRI. 19 patients underwent Transjugular intrahepatic portosystemic shunt (TIPSS) −2 were unsuccessful- 15/17 had TIPSograms, median of 4 TIPSograms/patient. 35/51 patients had endoscopy with a median of 2. 43/51 patients had a BM biopsy. 2 patients had liver transplant and 1 is awaiting intestinal and liver transplant. 7/51 underwent surgery needing ITU care. 48/51 received warfarin, 2 received DOACs and 1 received no anticoagulation (long-standing stable cavernoma). 23 patients received additional aspirin (13 with TIPSS). 82% received cytoreduction: 31 hydroxycarbamide, 19 ruxolitinib, 6 interferon; 10 had venesections. 29% had a new thrombosis, mainly venous (80%). Of these, 47% were new SVTs (4/7 with prior TIPSS, 1/7 prior thrombolysis). 17/51 (33%) had a new bleed, one fatal; 8 were on warfarin + aspirin. 20% had both a new thrombosis and a new bleed. 4 patients died, causes of death were: splenic aneurysm rupture, liver failure, leukemic transformation and infection. 29 patients completed at least one Symptom Assessment Form (SAF). Median overall QOL score of 4 (0 = best, 10 = worst). Median score 8 in PV and 2 in isolated JAK2v617f.Summary/Conclusion: MPN-SVT is rare but resource-intensive with high levels of morbidity and a significant effect on patients’ QOL. Our patients were managed intensively, despite this, fatality was 8% and recurrence of thrombosis 29%. These data highlight the urgent need to develop care pathways, treatment algorithms and establish clinical trials.

Background:Splanchnic vein thrombosis (SVT) includes extrahepatic portal vein obstruction (EHPVO), Budd‐Chiari syndrome (BCS) and mesenteric vein thrombosis. Myeloproliferative neoplasms (MPN) account for the majority of non‐cirrhotic SVT and are diagnosed in 30% of patients with EHPVO and 40% with BCS. SVT in MPN patients is associated with significant morbidity and mortality. There have been no prospective studies looking at this subset and there is very little in the way of guidance in managing this complex patient group.Aims:MASCOT is a prospective observational longitudinal study of patients with MPN related splanchnic vein thrombosis. The primary end points of the study are to describe morbidity/portal circulation in the patient group over 18‐24months from baseline, assess any changes in end points clinically and radiologically.Methods:29 patients from two centres were recruited and followed up for 24 months. Radiological primary endpoints, examined changes in initial thrombus, including thrombus extension or recurrence, recanalization in patients without cavernoma and changes in spleen size.Results:The male: female (M:F) was 13:16 with an average age of 48 years (25‐72). The majority of patients had an underlying diagnosis of polycythaemia vera (PV) 13 (45%), followed by essential thrombocythaemia (ET) 9 (31%) and the remaining patients had primary myelofibrosis (PMF), MPN‐unclassified (MPN‐U), post essential thrombocytosis‐MF (PET‐MF). Two patients did not have evidence of MPN on bone marrow histology. 27/29 had the JAK2v617f mutation; 2 had CALR mutation.Summary/Conclusion:In this prospective study of patients we did not observe recurrence or extension of SVT, however a small proportion of patients went on to develop further thrombotic complications whilst on anticoagulation. The study aims to follow patients for duration of five years with repeat imaging and clinical data.

OBJECTIVES:'Hub-and-spoke' networks may be one solution to reduce the geographical inequality in access to liver transplantation (LT) and the growing demands on, and saturation of, LT centres. It is not clear if such networks improve equity of access, deliver comparable patient outcomes or effect patient satisfaction. STUDY DESIGN:Retrospective evaluation of outcomes and patient satisfaction within the Royal Free liver transplant 'hub-and-spoke' network. METHODS:Patient outcomes in those assessed for LT between September 2011 and 2014 at spoke centres (n = 4) were compared retrospectively with those assessed at the LT hub centre. Patient satisfaction questionnaires were completed and changes in LT referral patterns were explored with data obtained directly from NHS Blood and Transplant (NHSBT). RESULTS:A total of 655 patients (180 spoke; 475 hub) were assessed for LT. Patients referred from spoke centres were more likely to have viral hepatitis as an underlying aetiology (72/180 vs 110/475; P < 0.001), or hepatocellular carcinoma (48/180 vs 60/475; P < 0.001) as an indication for LT and were more likely to be listed for LT when compared with hub patients (139/180 vs 312/475, P = 0.005). Mortality on the waiting list (9/123 vs 25/269, P = 0.57), waiting time to LT (64-days vs 78-days, P = 0.91) and Model for End-Stage liver disease (MELD)/United Kingdom End-Stage Liver Disease (UKELD) score (P = 0.24/0.26) in listed patients were equivalent as were 1- and 3-year patient and graft survival rates. Patient satisfaction rates were high at both types of centre, with significantly more patients preferring 'locally delivered care' at spoke vs hub (11/50 vs 70/73, P≤0.0001). Since the development of formal hub-and-spoke networks data from NHSBT based on postcode confirmed a significant increase in patients undergoing LT (153%) from spoke centres, whereas numbers assessed and transplanted from the hub centre have remained static. CONCLUSION:Hub-and-spoke LT networks are effective in offering equivalent clinical outcomes, high patient satisfaction and alleviate clinical pressure on the hub centre. They have to potential to help eliminate the geographical disparity in mortality rates from chronic liver disease.

Introduction Small bowel varices (SBV) occur as a consequence of portal hypertension and may result in life-threatening mid-gut bleeding. First line management usually involves radiological intervention (RI) (e.g. TIPSS, stenting of occluded mesenteric veins +/- embolisation of culprit varices). In cases where RI is impossible, management options become very limited. This case series evaluated the usefulness of DBE facilitated cyanoacrylate injection of SBV. Method Retrospective review of DBE facilitated cyanoacrylate injection of SBV at our institution (December 2015 to August 2016). Demographic, clinical, endoscopic and radiological findings, interventions and follow-up data were analysed. Results Seven DBEs were performed in 5 patients (3 women, median age: 73 years). Four patients had previous surgery (hemi-hepatectomy (n=2); SB resection (n=2)); one patient had a history of intra-abdominal sepsis in childhood causing portal vein thrombosis. No radiological or surgical options were deemed feasible in any case. SBV were diagnosed at capsule endoscopy and triple phase CT mesenteric angiography. At DBE, a total of 10 nests of SBV were identified and injected with cyanoacrylate glue. There were no haemorrhagic or embolic complications but 1 patient developed an infection of a congenital urachal cyst, which was treated successfully with antibiotics. All patients underwent DBEs via the anterograde route and 1 patient required bi-directional DBE for treatment of both proximal and distal SBV and another patient required a 2nd anterograde DBE for treatment of further patent proximal SBV. At 30 day follow-up post-therapy, only 1 patient had experienced a mild recurrence of mid-gut bleeding. Conclusion Cyanoacrylate injection therapy of SBV at DBE appears to be a safe and effective management strategy for this condition when other first-line options are not feasible. Disclosure of Interest A. Murino: None Declared, N Koukias: None Declared, E Vlachou Conflict with: Fujifilm and Aquilant Medical, K Planche: None Declared, D Patch: None Declared, E Despott Conflict with: Fujifilm and Aquilant Medical

Introduction Acute portal mesenteric vein thrombosis, when extensive, is associated with catastrophic complications of gut infarction, short bowel syndrome, PN dependence and death. The absence of a satisfactory therapeutic regimen has prompted the recommendation for alternative therapies (Hepatology 2010;51:210–218). Based on the safety profile of prolonged low dose tPA in children with extensive deep vein thrombosis, we have developed a ward-based TPA protocol to be used in patients with acute splanchnic vein thrombosis and symptoms/radiological signs of gut ischaemia. This treatment algorithm was approved by RFH DTC. Method Alteplase is commenced at a dose of 0.05 mg/kg/hr in patients with acute splanchnic vein thrombosis, after informed consent and an MDT decision involving surgery/radiology/hepatology. The standard contraindications to tPA apply. Monitoring involves 12 hrly FBC, clotting, fibrinogen. Thromboelastography/ROTEM were included as exploratory investigations. t-PA may be continued for 72 h. Contrast enhanced CT is performed at 48 h, or earlier if clinically indicated. TIPS is indicated if thrombus/symptoms persist at 72 h. Results To-date, 6 patients have been treated with this regimen. Aetiology of thrombosis was Chiari malformation (1) previously undiagnosed JAK2+ve MPD (2) local sepsis (1) and unknown (2) (see Table 1). Three patients had complete radiologic normalisation of their splanchnic circulation, 2 of whom also required TIPS due to persistent PVT. Two patients re-permeated their SMV with complete resolution of clinical symptoms and radiological signs of gut ischaemia, but with persistent PV thrombus. One patient did not have a radiological response, although their pain resolved. No patient required surgery for gut ischaemia. All patients survived and were discharged with normal enteric function. Two patients had their infusion interrupted; one for an arterial line puncture site bleed, and one for worsening gut symptoms (infusion re-started). Conclusion This early experience suggests that systemic tPA in patients with acute PMVT and symptoms/signs of gut ischaemia can be used to achieve resolution of thrombus and symptoms and avoid catastrophic complications of gut infarction. We propose that tPA is of value in a multi-modality approach to the management of acute splanchnic vein thrombosis. Disclosure of interest None Declared.

Introduction Porto-systemic shunt embolization (PSSe) is an emerging procedure for the treatment of refractory hepatic encephalopathy (HE).1A criteria of MELD <11 was proposed by Laleman et alas a cutodd to predict recurrent HE post embolization. No other significant liver-related complications were noted in this retrospective study. The aim of this retrospective study was to assess the efficacy and complication rate following PSSe at a single institution. Method All cirrhotic patients undergoing PSSe for refractory HE between March 2008 – September 2014 at Royal Free London were included in this study. Cirrhotic patients had refractory HE (West Haven score ≥2), an EEG pattern consistent with HE, and a demonstrable PSS on CT/MRI. All patients underwent embolization using Amplatz vascular plugs. Clinical and biochemical variables at the time of PSSe were recorded, and outcomes including HE grade, changes in MELD score and portal hypertension-related complications were noted. Results Ten patients underwent PSSe (M: 6; Age 60.9 ± 10.3 yr) and mean follow up was 37.3 ± 59.6 mo. A baseline MELD score >11 was present in 5 patients. No significant change in mean MELD score was seen following PSSe (11.5 ± 2.8 vs 12.2 ± 6.9, pre vs post p = 0.57). No patients experienced variceal haemorrhage post PSSe. Five patients had diuretic controlled ascites prior to PSSe. Following PSSe two patients developed severe ascites requiring large volume paracentesis (Table 1). HE improved in 6 patients; recurrent HE developed in 4 patients – grade 3 in 2 patients, and grade 4 in 2 patients (Table 1). MELD >11 did not predict occurence of ascites or HE post PSSe. Conclusion This small retrospective series demonstrates a 20% incidence of severe ascites post PSSe. With the caveat of the small size of this cohort, MELD score did not predict ascites or HE following PSSe. Further assessment of degree of portal hypertension, or of porto-systemic shunting, through hepatic haemodynamic and ICG studies may better predict the development of complications and the necessity for a concomitant TIPS at the time of PSSe. Disclosure of interest None Declared. Reference Laleman W, et al. Embolization of large spontaneous portosystemic shunts for refractory hepatic encephalopathy: a multicenter survey on safety and efficacy. Hepatology 2013;57:2448–2457