Factors Associated With Mortality In Immune-Mediated Thrombotic Thrombocytopenic Purpura: Results From The United States Thrombotic Microangiopathy Ttp Registry

Background: Thrombotic Thrombocytopenic Purpura (TTP) is a life threatening microangiopathy used by a deficiency in ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13). ADAMTS13 cleaves von Willebrand factor, and ADAMTS13 deficiency leads to an excess of high molecular weight multimers of von Willebrand factor which, in turn, causes platelet aggregation and congestion in small arteries and organ damage. TTP occurs in two forms: inherited due to a congenital defect in either production or function of the protein, and immune-mediated due to autoantibody formation either leading to immune clearance or inhibition of the function of the enzyme. TTP is a medical emergency and if untreated carries a mortality rate of approximately 90 percent. Current therapies (plasma exchange, immunomodulatory agents) have improved outcome in this disease, but mortality remains unacceptably high at approximately 10 percent. Attempts have been made to identify factors placing patients at higher risk for adverse outcomes, perhaps signaling the need for more aggressive treatment in these patients.