Therapeutic plasma exchange and plasma infusion in thrombotic microvascular syndromes. Barz D, Budde U, Hellstern P. Thrombosis Research 2002;107 Suppl 1:S23-27.

ABSTRACT:

Plasma exchange (PE) is the most important treatment in thrombotic microangiopathies (TMAs) mainly encompassing thrombotic thrombocytopenic purpura (TTP) and adult hemolytic syndrome (HUS). Adult HUS cannot be clearly distinguished from TTP with respect to clinical features and outcome. While children typically recover from acute episodes of HUS and do not require PE treatment, adults appear to benefit from PE irrespective of the etiology of HUS. Therapeutic PE and plasma infusion are the most effective and indispensable therapeutic measures in TTP-HUS. PE has been found, however, to be superior to plasma infusion, both in response rate and mortality rate. This therapeutic measure has substantially improved clinical outcome. There is a variable response to PE, however, probably reflecting the variety of conditions that cause TTP-HUS. Relapses occur in 30-60% of survivors of TTP-HUS and can be classified into two categories: those occurring within four weeks after PE cessation are considered disease exacerbations; those occurring later are considered late recurrences. Exacerbations are observed in two-thirds of patients with relapses. Cases caused by E. coli O157:H7 infection respond rapidly and completely for the most part. In refractory cases, additional treatment may be considered. The importance of additional or alternate measures, however, including glucocorticoids, antiplatelet agents, splenectomy, intravenous immunoglobulins, protein A columns, vincristine, cyclosporine, and cyclophosphamide, is uncertain. Side effects of PE vary from minor to severe, and the proportion of TTP-HUS patients with side effects has ranged from 8% to over 60%. Whether cryosupernatant plasma (CSP) or solvent/detergent-treated (SDP) plasma is superior to standard fresh frozen plasma (FFP) remains to be determined. Methylene blue-treated plasma seems to be less effective than standard FFP. A large randomized clinical trial should be conducted to determine if SDP is superior to FFP and CSP with respect to efficacy and adverse events.