Analyses of data of patients with Thrombotic Microangiopathy in the WAA registry

Thrombotic Microangiopathy (TMA) is a histopathological feature of various diseases including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome.The aim of this study was to investigate the outcome and prognostic variables of TMA-patients.Materials and methodsData were consecutively retrieved from the WAA-apheresis registry (www.waa-registry.org) during 2003–2009. Included were all 120 patients (1237 procedures) who suffered from various forms of TMA, as registered by the ICD-10 code M31.1. Besides registry data, more extensive information was retrieved from the latest 64 patients. Adverse events of the TMA patients were compared to those of the other patients in the registry.ResultsThe mean age was 46 years (range 11–85 years, 57% women). In 72% therapeutic apheresis was due to an acute indication while a long-term indication was present in 28%. Plasma exchange was performed by centrifugation and filtration technique (95% and 4%, respectively), and immunoadsorption in 1% of the patients. Only fresh frozen plasma was used as replacement fluid in 69% of procedures. Adverse events were more frequent than in the general apheresis population (10% versus 5%, RR 1.9, CI 1.6–2.3). No death occurred due to apheresis treatment. Three percent of the procedures were interrupted. Bronchospasm and/or anaphylactic shock were present in two patients and one patient suffered from TRALI. At admission 26% were bedridden and needed to be fed. The risk of dying during the treatment period was significantly higher if the patient also suffered from a compromising disease, such as cancer. There was an inverse correlation between the ADAMTS13 level and the antibody titer (r = −0.47, p = 0.034).ConclusionsPatients with TMA have an increased risk for moderate and severe AE compared to the general apheresis population. Many patients were severely ill at admission. The prognosis is worse if the patient also has a severe chronic disease. Even slightly increased ADAMTS13-antibody titers seem to have a negative impact on the ADAMTS13 levels.