Abstract: Objective Analyze the clinical and laboratory characteristics, plasmapheresis response rate and outcomes in patients with thrombotic microangiopathy of different etiology. Methods Retrospectively review all the patients diagnosed as TMA and accepted therapeutic plasmapheresis during 2005 and 2013 at our center. Their clinical, laboratory characteristics, treatments, follow-ups and outcomes were investigated． Results Altogether there are 22 patients with 9 males and 13 females. The average age is 33.1±13.8y. Two of them are primary or idiopathic TMA with benign course, excellent responses to PE treatment (100%) and high survival rate. Three of them are (systemic lupus erythematosus,SLE) related TMA with severe kidney damage and need renal replacement therapy. The relief rate of PE treatment and survival rate is 33.3%. There are 17 hematopoietic stem cell transplantation associated TMA patients. Their kidney injuries are mild and they don’t need renal replacement therapy. We found a response rate of 41.1% to PE, of whom 17.6% attained complete remission. The long prognosis in this group is poor and the survival rate is only 11.8%. Conclusion Responses are excellent with primary or idiopathic TMA while are poor in patients who presented with TMA secondary to underlying disorders. Plasmapheresis is a first-line recommendation for primary TMA. However, it can be concerned as a second- line therapy for patients with secondary TMA if they are resistant to routine treatments.

Key words: Plasmapheresis, Thrombotic microangiopathy, Thrombotic thrombocytopenic purpura, Hemolytic uremic syndrome, Hematopoietic stem cell transplantation