Therapeutic plasma exchange for the treatment of thrombotic thrombocytopenic purpura: a retrospective multicenter study.

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a rare disease that is fatal if it is not treated. Therapeutic plasma exchange (TPE) has resulted in excellent remission and survival rates in TTP patients. MATERIAL AND METHODS: We describe our experience with 52 TTP patients treated with TPE during the past eight years (65% of the patients were females; patient median age=34 years, range: 17-73). TPE was carried out 1-1.5 times plasma volume. Fresh frozen plasma (FFP) or cryosupernatant plasma (CSP) was used as the replacement fluid. TPE was performed daily until normalization of serum LDH and recovery of the platelet count to >150 x 10(9)/dL; TPE was then slowly tapered. Clinical, laboratory data, the number of TPE, other given therapy modalities, treatment outcomes and survival rate were evaluated retrospectively. RESULTS: Overall response (OR) and complete response (CR) rates were 77% and 60%, respectively. Response was excellent in 82.8% of the patients with primary TTP among whom 74.2% were CR. Additionally, there were statistical differences in terms of CR rate between patients with primary TTP and secondary TTP (74.2% vs. 29.4%; p=0.005). OR and CR rates were 79% and 57.9% in patients on TPE alone and 75.8% and 60.6% in patients on TPE+prednisolone, respectively (p=1 and p=0.8). Additionally, there were no statistical differences in terms of OR and CR rates between patients on TPE with FFP and CSP (p=0.25 and p=0.16, respectively). The presence of fever and the number of TPE were statistically important factors influencing the probability of response in multivariate logistic regression analysis (p<0.01 and p<0.01, respectively). Additionally, in multivariate Cox's regression analysis, the probability of survival was higher in patients who were responsive to treatment compared to patients who were unresponsive (p<0.001). CONCLUSION: TPE is an effective treatment for primary TTP; however, it may be used as adjunctive therapy for secondary TTP until it is under control. The addition of steroids to TPE had no advantage compared to TPE alone. CSP as replacement fluid is not superior compared to FFP. Fever appears to be a bad prognostic indicator. Therefore, prolonged treatment with TPE may be needed in patients with fever.