How effective and safe is low-dose aspirin for long-term primary and secondary prophylaxis of arterial and venous thrombotic events in patients with polycythaemia vera (PV) and essential thrombocythaemia (ET)?
The reduction in risk of fatal thrombotic events was not statistically significant.
PV and ET are chronic myeloproliferative disorders with an increased risk of arterial and venous thrombosis, as well as bleeding. Based on the estimated individual risk of thrombotic and bleeding complications, different therapeutic strategies are available: phlebotomy for PV or platelet apheresis for ET, cytoreductive therapy (e.g. hydroxyurea, anagrelide, interferon-a) and aspirin to prevent platelet aggregation.¹ However, long-term administration is associated with an approximately two-fold increase in the risk of major upper gastrointestinal bleeding (one to two bleeding events per 1000 patients per year), and with an absolute excess of haemorrhagic strokes of one to two per 10,000 patients.²`³ 1. Campbell PJ et al. Haematology/the Education Program of the American Society of Haematology 2005 ;1 :201-208. 2.Harrison CN et al. NEJM 2005 ;353 :33-45. 3. Landolfi R et al. NEJM 2004 ;350 :114-124.