Study of fibrinolytic parameters in different types of polycythemia.

Polycythemia vera (PV) is a myeloproliferative disorder characterized by thrombotic and, less often, bleeding complications. Many mechanisms have been advanced to explain the occurrence of these complications, none of them satisfactory. We examined a cohort of 27 patients with PV, secondary erythrocytosis, and essential thrombocythemia for coagulation and fibrinolytic parameters, including euglobulin lysis test, D-dimer, and alpha2 antiplasmin. Ten of the 27 patients developed one or more thrombotic complications during the study. We found no clinical correlation between the studied parameters and the complications. Three patients, one of each group, with elevated serum alpha2 antiplasmin levels, developed severe arterial or venous thromboses.