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.
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.
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.
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.
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.