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

Summary.  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 ≥ 0.05μg L⁻¹ (normal range 0–0.01 μg 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 μg L⁻¹ (58.5% (range 17–162%), compared with patients with troponin T < 0.05 μg L⁻¹ (35%, range 9–134%). Patients who died had higher troponin T levels (median 0.305 μg L⁻¹) and raised anti-ADAMTS 13 IgG (median 66.5%). On admission, there were no deaths in those with troponin T ≤ 0.04μg 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 μg 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.