Background and purpose: Since the advent of routine automated blood cell counts, an increased platelet count often is detected fortuitously in asymptomatic individuals. In the past, essential thrombocythemia (ET) was thought to be linked to an increase incidence of hemorrhagic complications, whereas thrombosis is now considered more frequently. Actually, the risk of thrombosis cannot be predicted in an asymptomatic patient with essential thrombocythemia.
Patients and methods: A total of 41 young patients (age range, 18 to 45 years) affected by ET and diagnosed in agreement with the Polycythemia Vera Study Group criteria are reported. Common risk factors, such as hypertension, smoke, obesity, dyslipidemia, and diabetes, have been registered. Particular attention has been given to cerebral vascular accidents (CVA) both of the arterial and venous systems. Platelet number, platelet serotonin content, and platelet aggregation under collagen, adenosine diphosphate (ADP), and adrenalin stimuli were evaluated.
Results: Nine out of the 41 patients affected by ET had CVAs, four of which occurred in the venous system. No difference in platelet function tests has been observed between patients with or without CVA. Six out of the 9 patients with ET and CVA had at least one atherosclerotic risk factor: four were heavy smokers, one had hypertension, and one had hypertension and obesity.
Conclusions: Cerebral vascular accidents are confirmed to be frequent in patients with essential thrombocythemia, even at a young age. However, the presence of at least one atherosclerotic risk factor associated with increased platelet number seems to favor thrombotic complications. In particular, cigarette smoking seems to be related to arterial CVAs in essential thrombocythemia.