BACKGROUND: Essential thrombocythemia (ET) is a myeloproliferative disorder characterized by absolute thrombocytosis and increased incidence of thrombosis and hemorrhage. But the risk of thrombosis or hemorrhage cannot be accurately predicted and the indications for therapy remain unclear. The purpose of this study was to determine the influence of cardiovascular risk factors, e.g. smoking, hypertension, hyperlipidemia and diabetes mellitus, upon complications of ET.
METHODS: We have retrospectively analyzed the influence of cardiovascular risk factors upon vascular complications for 37 cases of ET diagnosed at Taegu between January 1987 to December 1996. The PVSG criteria was used to diagnose ET.
RESULTS: The mean age of all patients was 55 years(male patients, 58 years; female patients, 53 years). The average platelet count at diagnosis was 1,308×10(9)/L. Eighteen patients (49%) presented with thrombotic complications, and seven (19%) with hemorrhages. Disturbances of microcirculation (30%) were the most frequent thrombotic symptoms. Age and the degree of thrombocytosis did not influence the rate of vascular complications, but patients with cardiovascular risk factors had higher rate of vascular complications. Arterial complications,
such as femoropopliteal and coronary artery thrombotic disease, were exclusively seen in patients with cardiovascular risk factors, especially cigarette smoking.
CONCLUSION: A group of patients with cardiovascular risk factors, especially smoking have high risk for arterial thrombotic complications of ET, for whom aggressive preventive therapy of cardiovascular disease should be considered.

Keywords: Essential thrombocythemia, Cardiovascular risk factors, Thrombosis