Ó³»­´«Ã½

BACKGROUND: Immune thrombotic thrombocytopenic purpura (iTTP) is a hematologic disorder characterized by severe acquired deficiency in ADAMTS13, resulting in thrombotic microangiopathy and death if untreated. Plasma exchange (PLEX) is the backbone of iTTP management and has improved survival in this disorder. Guidelines suggest initiation of PLEX within 4-8 h of presentation; however, there is little evidence to guide the precise timing of PLEX, and barriers exist to its timely deployment.STUDY DESIGN AND METHODS: We examined determinants of time between symptom onset to PLEX initiation (S2P) and hospital presentation to PLEX initiation (door to PLEX, D2P) in a large iTTP research cohort at an academic medical center.RESULTS: In 225 cases occurring in 143 unique patients, the median (IQR) S2P time was 4.28 (1.92-7.47) days. In linear mixed effects regression analysis, increased S2P was associated with greater distance from a participating apheresis center (p = .01) and higher presenting platelet count (p = .046), while relapse presentation was associated with shorter S2P (p = .036). The median (IQR) D2P time was 8.4 (5.03-15.63) h. Longer D2P time was associated with a higher presenting platelet count (p = .002) and trended towards association with male sex (p = .057). Increased S2P and D2P times were not associated with hospital length of stay, mortality, or the composite of mortality and ICU stay.CONCLUSION: Our data show that different factors contribute to the interval between symptom onset and presentation versus the time between presentation and initiation of therapy in iTTP.