Flowchart of individuals included in the analysis. A total of 222 individual patients were treated for acute iTTP at the Johns Hopkins Hospital or OSU, of whom 9 died during the index iTTP episode. The remaining 213 patients were including in the analysis of mortality after an episode of acute iTTP. A subset of 98 patients had available measurements of ADAMTS13 activity in remission and were included the analysis evaluating the association of reduced ADAMTS13 activity in remission with mortality.