Multicenter Analysis of Clinical Characteristics and Long-Term Outcomes of Transjugular Intrahepatic Portosystemic Shunt Procedure for MPN-Associated Portal Hypertension
Authors: Reilly Christopher R , Babushok Daria V. , Martin Karlyn , Spivak Jerry L. , Streiff Michael , Stein Brady , Moliterno Alison R , Hexner Elizabeth O. 
Published: October 2019

Abstract
The myeloproliferativeneoplasms (MPNs), polycythemia vera(PV), essential thrombocythemia(ET), and primary myelofibrosis(PMF), are clonal stem cell disorders defined by proliferation of one or more myeloid lineages and variable progression to myelofibrosisand leukemia. Portal hypertension (pHTN) occurs in 7-18% of MPN patients and portends a poor prognosis. The most common causes of MPN-associated pHTNinclude splanchnic vein thrombosis (SVT), extramedullaryhematopoiesis (EMH), and nodular regenerative hyperplasia (NRH). pHTNin MPN patients presents similarly to that in patients with cirrhosis, with refractory ascites, gastrointestinal bleeding, and hepatic encephalopathy. Transjugularintrahepatic portosystemicshunt (TIPS) insertion has been used empirically to treat refractory ascites and varicealbleeding in MPN-associated pHTN; however, little data exists on long-term outcomes of MPN patients who have undergone TIPS procedure. To assess the safety and efficacy of TIPS for treatment of pHTNin MPN, we performed a retrospective analysis of outcomes of TIPS procedure in MPN patients at three academic medical centers.
Through a defined search of the electronic medical records of the participating institutions, 29 MPN patients were identified who underwent TIPS procedure forpHTNbetween 2000 and 2016. Patients with portal hypertension from causes other than MPN were excluded from the study as were patient with fewer than 6 months of follow-up. Clinical characteristics and long-term outcomes were analyzed.
The mean age of the patients was 51.5 years (range 29-86 years) and 65.5% were women. PV and PV-MF were the most common MPN subtypes (58.6%), followed by MPN unclassifiable (20.7%), PMF (10.3%), and ET (10.3%) (Table 1).JAK2V617F mutation was present in all but one patient, while CALR and MPL mutations were detected in one patient each. Budd-Chiari syndrome (BCS) represented the predominant etiology of portal hypertension in 72.4% of patients. Of note, 31% of patients had a multifactorial etiology of portal hypertension. Females with PV comprised 75% of BCS presentations, whereas males with MF comprised 80% of EMH. Indications for TIPS included refractory ascites (86%), esophagealvarices (51.7%), intestinal ischemia (6.9%), and fulminant liver failure (6.9%). All patients demonstrated immediate normalization of portal pressures following TIPS insertion with a covered-uncovered stent-graft. Post-TIPS anticoagulation included warfarin (69%), low-molecular weight heparin (17.2%), andfondaparinux (17.2%). Four patients (13.8%) did not receive anticoagulation following TIPS, two of whom had knownvarices and one who had gastro-intestinal bleeding following TIPS. The majority of patients experienced complete resolution of ascites (96.2%) andvarices (93.3%). Post-TIPS complications included TIPS thrombosis (31.0%; notably these occurred despite anticoagulation), heparin-induced thrombocytopenia (20.7%), low-grade hepatic encephalopathy (20.7%), TIPS stenosis (17.2%), and mild NSTEMI (1 patient). Of the eight patients listed for liver transplant, only one patient required transplant following TIPS. One, two, and three-year overall survival post-TIPS were 96.4%, 92.5% and 85.2%, respectively.
Our study represents the largest cohort to date of MPN-associated portal hypertension patients who received TIPS. Our results indicate that TIPS can be performed safely in this high-risk population and can effectively mitigate the clinical consequences of MPN-associatedpHTN. However, the risk of TIPS complications, particularly of thrombosis and hepatic encephalopathy, remains prevalent and must be balanced against the intended clinical benefits.

Disclosures
Stein: Incyte: Membership on an entity's Board of Directors or advisory committees.