Therapeutic thrombocytapheresis
This chapter discusses therapeutic thrombocytapheresis which involves the removal of platelet from patients with thrombocytosis, who have a platelet count of >500,000/μl. Thrombocytosis can be a primary disorder occurring as a result of myeloproliferative disorders, including polycythemia vera, essential thrombocythemia and chronic myelogenous leukemia or as secondary phenomenon such as acute bleeding, hemolysis, infection and inflammation among others. Thrombocytapheresis is usually not indicated in secondary disorders but can be indicated in myeloproliferative disorders because the platelets are functionally abnormal, leading to thromboembolic events. Thrombocytapheresis should be performed daily or as needed to prevent recurrent or progressive thromboembolism or hemorrhage in patients with myeloproliferative disorders. In addition, thrombocytapheresis may be appropriate for selected high-risk patients when platelet-lowering agents are contraindicated or intolerable or when the onset of pharmacologic therapy would be slow. The usual goal is to achieve a platelet count of <600,000/μl. The total blood volume usually processed is two, resulting in a 30-60% decrease in platelet count.
