Hemorrhagic and thrombotic complications in polycythemia vera. A clinical study.

This study reviewed the clinical and hematologic characteristics of 161 patients with polycythemia vera treated with myelosuppressive agents, with or without antiaggregating platelet therapy, in order to determine the features associated with a risk of hemorrhagic or thrombotic complications. At presentation, 7 patients (4.3%) showed hemorrhages and 36 (22%) complained of thrombotic events. None of the evaluated clinical and hematologic parameters was significantly related to hemorrhagic or thrombotic presentation. During the clinical course, four of 107 patients (3.7%) experienced hemorrhagic complications and 34/107 patients (28%) complained of occlusive events, which accounted for 30% of total deaths. Among the clinical and hematologic presenting features, only age over 60 yrs could be identified as an unfavorable prognostic factor for the occurrence of thromboembolic episodes. Marked thrombocytosis, a high packed cell volume (PCV) and the thrombotic onset were not significantly related to the thrombotic risk. Platelet count and PCV at the time of the occlusive episode did not correlate with the clinical event; however, inadequate control of the proliferative disease seemed to increase the thrombotic tendency. Antiaggregating drugs, although unable to avoid thrombosis in our experience, might be safely associated with the myelosuppressive therapy, particularly in selected patients.