Durable remissions following prolonged plasma exchange in thrombotic thrombocytopenic purpura

We evaluated the efficacy of prolonged plasma exchange (PEX) for attaining durable remissions in thrombotic thrombocytopenic purpura (TTP). A recent review using steroids or PEX in initial management showed an 80% response rate but produced a relapse rate of 67-84%. Records of 50 patients starting PEX treatment for TTP/HUS were reviewed to identify and select those whose course of treatment had ended over 1 year earlier, whether or not the result was satisfactory. Records were evaluated for outcome, especially remission associated with treatment by "prolonged" plasma exchange. "Prolonged" was defined as continuing PEX beyond the stage where a normal platelet count was attained and until evidence of hemolysis was "minimal or at least compensated." If disease activity as judged by the criteria of hemolysis became accelerated or resumed, PEX was increased by volume of FFP (e.g., from 3 to 4 L) or rate (from less than daily to daily). Of 50 consecutive patients treated by PEX for TTP/HUS there were 40 cases after which at least one year had passed since the end of treatment. These 40 patients were evaluated for the results of treatment by PEX. Eight failed to achieve remission, dying in hospital within 1 month of admission. Twenty-eight achieved remission, sustained for 1 year or more in all. These are the reasons for our enthusiasm about this report. Four achieved remission lasting less than 1 year. Splenectomy was performed to obtain a sustained remission in one patient following administration of three 2 mg doses of vincristine and two relapses.(ABSTRACT TRUNCATED AT 250 WORDS)