High rate of abnormal blood values and vascular complications before diagnosis of myeloproliferative neoplasms.

Background: Vascular complications occurring before the diagnosis of myeloproliferative neoplasms (MPN) in 612 patients from four centers in Sweden, Denmark and France were retrospectively studied.

Results: Vascular complications were observed in 151 (25%) of the 612 patients. Of these, 66% occurred during the two years preceding diagnosis.