PREVENTION AND TREATMENT OF THROMBOTIC COMPLICATIONS IN ESSENTIAL THROMBOCYTHEMIA - EFFICACY AND SAFETY OF ASPIRIN

The efficacy and safety of aspirin in the prevention and treatment of thrombosis in essential thrombocythaemia (ET) was retrospectively anal ysed in a cohort of 68 ET patients, 41 patients presented with thrombo sis, five patients with bleeding; two patients had a paradoxical combi nation of bleeding and thrombosis at presentation. At presentation, pa tients with bleeding had significantly higher platelet and leucocyte c ounts than patients with thrombosis. During long-term follow-up the in cidence of thrombosis was significantly reduced in patients receiving aspirin, either as monotherapy or in combination with cytoreduction. H owever, treatment with aspirin (500 mg/d) was associated with an incre ase in (minor) bleeding complications. In patients receiving aspirin, bleeding occurred particularly at platelet counts exceeding 1000 x 10( 9)/l. The overall 5- and 10-years survival probability was 93% and 84% respectively, indicating that life expectancy in ET is close to norma l. Although our data need confirmation in prospective clinical trials, they suggest that aspirin, particularly in lower doses (100 mg/d), ma y be a safe antithrombotic agent in ET with an acceptable risk for ble eding, if applied to patients with a platelet count <1000 x 10(9)/l an d/or absence of a bleeding history.