Prognostic relevance of early clinical and laboratory findings in immune-mediated thrombotic thrombocytopenic purpura.

Background: Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a life-threatening condition caused by a severe deficiency of a disintegrin and metalloproteinase with thrombospondin type 1 motif 13 due to autoantibodies. Despite modern treatments, including therapeutic plasma exchange, immunosuppression, and rituximab, early mortality-often due to cardiac and neurologic events-remains a concern. Methods: We analyzed data from 125 patients between 2010 and 2023 in the Japanese thrombotic thrombocytopenic purpura (TTP) registry, examining demographics, electrocardiogram and transthoracic echocardiography findings, and neurologic symptoms. Troponin I was measured. Outcomes were categorized as survivors, TTP-related deaths, and non-TTP-related deaths. Results: Of the 125 patients, 15 died, with 5 deaths directly related to iTTP. Early cardiac findings and neurologic symptoms were not significant predictors of mortality. However, elevated lactate dehydrogenase levels and reduced von Willebrand factor multimer indices correlated with poorer prognosis. Patients with myocardial hypokinesis finally recovered their condition during the course of treatment. No patient treated with caplacizumab died during the observation period. Conclusions: These findings suggest that early cardiac and neurologic symptoms may not be definitive predictors of iTTP-related death. Instead, extremely high lactate dehydrogenase levels indicated a worse prognosis, highlighting the need for targeted monitoring and interventions in high-risk cases.