Relationships between thrombohemorrhagic complications and platelet function in patients with essential thrombocythaemia

Three subgroups have been distinguished in essential thrombocythaemia (ET) patients, on the basis of clinical and laboratory findings. ET patients wit h bleeding Incidents had smaller platelet volume, lower concentrations of b eta -thromboglobulin and platelet factor 4 in their plasma, 10%, 26%, and 2 6% lower compared to patients without complications, respectively. ATP secr etion from platelets of bleeders, clotters, and "no-complications" ET patie nts was found to be 75%, 36%, and 45%, respectively, lower than in healthy people. Spontaneous platelet aggregation appeared to be normal in about 90% of ET patients with no complications and in all bleeders but only in 35% p atients with clotting incidents. All bleeders had abnormal agonist-evoked a ggregation assays. Among remaining ET patients 30%-60% displayed normal val ues of different evoked aggregation tests. Thus, clinically distinguished g roup of bleeding ET patients may be differentiated from other subgroups on the basis of laboratory findings. Am. J. Hematol. 68:32-36, 2001. (C) 2001 Wiley-Liss, Inc.