Splenectomy after portal thrombosis in patients with polycythemia vera and essential thrombocythemia.

Background and Objectives: Polycythemia vera (PV) and essential thrombocythemia (ET) are two rare acquired myeloproliferative disorders (MPD) with frequent thrombotic and hemorrhagic complications. The occurrence of thrombosis in unusual sites, e.g. splanchnic vasculature, is a severe complication of these diseases. We describe a single-institution experience in patients with ET and PV, diagnosed in agreement with the Polycthemia Vera Study Group criteria, with portal vein thrombosis who did or did not undergo splenectomy.
Design and Methods: The medical records and the follow-up outcome of 16 MPD patients with portal thrombosis who underwent splenectomy (group A1) and 16 who did not (group A2) were evaluated. Their median follow-up was, respectively, 13.45 and 10.49 years. The overall survival of these patients was compared with that of a population of 32 patients with MPD and no portal thrombosis (group B) matched for sex, age, diagnosis and duration of follow-up.
Results: In group A1, 2 patients developed deep vein thrombosis, 1 patient had a surgical hemorrhage and 2 patients died early, one from acute infection, the other from bone marrow aplasia. Among the survivors, one male had a deep vein thrombosis and 1 developed a new portal thrombosis. Four patients died during the follow-up (median 9.48 years, range 3.17-25.1; 1 stroke, 2 gastrointestinal bleedings, 1 leukemic conversion). No difference was observed in the incidence of thrombotic or hemorrhagic complications or in the rate of deaths when group A1 was compared to the other groups. The use of antiplatelets drugs was statistically increased in group A1 after splenectomy, because portal vein thrombosis induced per se an increased use of therapeutic agents. No statistical difference was observed in overall survival between the different groups.
Interpretation and Conclusions: 1) Bleeding and thrombosis are the leading causes of morbidity and mortality in ET and PV patients with portal vein thrombosis both with or without splenectomy. 2) Portal vein thrombosis, and sometimes splenectomy, requires increased use of drugs which may enhance the risk of leukemic transformation. In spite of this, the patients who survive the first post-splenectomy period may have a long and safe life.