The aim of this study is to determine the frequency of cardiac and cerebral involvements in patients with idiopathic thrombotic microangiopathies on diagnosis. Patients will be assessed for cardiac involvement (troponin Ic level and cardiac ultrasonography) and cerebral involvement (cerebral MRI). The investigators will assess whether serum troponin Ic on diagnosis can predict morbidity and mortality of patients with a thrombotic microangiopathy at the acute phase.

The primary outcome measurement is the event free survival at day 30, as defined by death, myocardial ischemia, arrhythmia, severe cerebral injury and disease exacerbation. An increase in troponin Ic on diagnosis is defined as at least one result above 0.2 ng/ml among the three daily analyses performed after TMA diagnosis.

After TMA diagnosis, patients will be treated in emergency according to standard National recommendations. Patient will be included in the study as soon as the diagnosis of TMA is performed.

From day 1 to day 3, specific blood tests will be performed (serum troponin Ic and brain natriuretic peptide [BNP]). A cardiac ultrasonography within the 4 first days and a cerebral MRI within the first 7 days after TMA diagnosis will be performed.

Our hypothesis is that an increased serum troponin Ic level on diagnosis (> 0.2 ng/ml) is a predictive feature of cardiac events or worsening at the acute phase.

At 6 months, a control cardiac ultrasonography and cerebral MRI will be performed in patients with cardiac and/or cerebral involvement on diagnosis.

122 patients are expected to be included among 30 recruiting centres in France. The total duration of inclusions is 2.5 years, and the total duration of the study is of 3 years.

Inclusion Criteria:

• A diagnosis of thrombotic microangiopathy on the following criteria :
• A microangiopathic haemolytic anaemia (Hb< 12 g/dl, with presence of schistocytes on blood smear);
• A thrombocytopenia <150 G/l;
• No associated (precipitating) disease (HIV infection, cancer, chemotherapy, transplantation) or pregnancy;
• A written consent obtained from the patient, or from a relative for patients unable to provide the informed consent (because of cerebral involvement for example);
• Affiliation at the social insurance regimen.
• Major person

Exclusion Criteria:

• A TMA associated with an associated condition: infection with HIV (HIV) in AIDS stage, , chemotherapy, malignancy, transplantation, or pregnancy.