Thrombotic thrombocytopenic purpura: treatment with plasmapheresis.

Twenty-one episodes of thrombotic thrombocytopenic purpura (TTP) were treated with plasmapheresis. Adjunctive agents included corticosteroids, aspirin, dipyridamole, and vincristine. There were 17 patients; 12 were female. The median age was 41 years. Most patients presented with neurologic symptoms. Thrombocytopenia was profound with a mean initial platelet count of 14,900/mm3. The mean hematocrit on presentation was 26.7% and the mean LDH 1300 IU/L. Eighteen episodes responded completely following plasmapheresis/plasma exchange (86%). Response was prompt, the initial rise in platelet count occurred after a mean of four exchanges, and complete response (a platelet count over 150,000/mm3) was obtained after a mean of nine exchanges. Four of the episodes treated were relapses that occurred in three patients. All responders are alive with a median duration of follow-up of 20 months. The three patients who failed to respond have died. This report extends recent observations that the addition of plasmapheresis/plasma exchange to the therapy of TTP has significantly improved the outlook for patients with this disorder.