Cardiac involvement in acute thrombotic thrombocytopenic purpura: association with troponin T and IgG antibodies to ADAMTS 13

Introduction: Evidence for cardiac involvement in thrombotic thrombocytopenic purpura (TTP) is uncommonly described. Methodology: We retrospectively reviewed 41 patients assessing troponin T as a marker for cardiac involvement in acute TTP with clinical symptoms, electrocardiograms (ECG) and echocardiograms. A histopathological review of five patients who died of acute TTP was also undertaken. Results: In 54% (22/41) of patients, troponin T was >= 0.05 mu g L-1 (normal range 0-0.01 mu g L-1). Half (12/22) had cardiac symptoms and 8/22 with a raised troponin T reported chest pain. ECG changes were present in 62% of patients with a raised troponin T. Median anti-ADAMTS 13 IgG antibody was significantly higher (P = 0.018) in patients with troponin T >= 0.05 mu g L-1 (58.5% (range 17-162%), compared with patients with troponin T < 0.05 mu g L-1 (35%, range 9-134%). Patients who died had higher troponin T levels (median 0.305 mu g L-1) and raised anti-ADAMTS 13 IgG (median 66.5%). On admission, there were no deaths in those with troponin T <= 0.04 mu g L-1. Histology confirmed widespread myocardial microvascular thrombi. Conclusion: Clinical symptoms, ECG changes and echocardiograms are poor predictors of cardiac disease in acute TTP. Troponin T is specific for cardiac muscle and a sensitive marker of myocardial damage. In TTP patients, raised levels (>= 0.05 mu g L-1) signify myocardial necrosis associated with microvascular thrombi. Mortality and acute morbidity was associated with higher admission troponin T and raised IgG antibody (> 67%) to ADAMTS 13.