Added Value of Speckle Tracking in the Evaluation of Patients With Sickle Cell Disease

Sickle Cell Disease is a serious disease that is life-threatening for patients being homozygous for the SS form or heterozygous for the SC or βthal forms. The CHU Brugmann hospital currently regularly treats about 70 homozygous adult patients and this number is in constant augmentation.

Sickle cell disease patients may develop a cardiomyopathy due to chronic anemia, the haemosiderosis risk or, less frequently, to coronary vaso-occlusive damages.

The hypervolemia in patients with sickle cell disease causes an overestimation of the ejected left ventricular fraction measured by echocardiography, this parameter being very dependent of the blood volume.It has already been shown that the left ventricular ejection fraction was normal in most patients with sickle cell disease, but that its evaluation by parameters independent from the blood volume showed the existence of a dysfunction.

Myocardial strain, as measured by speckle tracking, is a echographic evaluation method of the cardiac function, independent of the blood volume. This technique hasn't been used much in sickle cell disease patients. A study using 3D speckle tracking on a limited number of sickle cell disease patients failed to show a strain anomaly. Moreover, the study highlighted a higher global longitudinal strain in this patient population. The investigators find these data hard to explain and in contradiction with previous studies using other cardiac function evaluation techniques, independent from the blood volume.

The primary goal of this study is thus

* to study the longitudinal strain by 2D echography * to determine if anomalies of the longitudinal strain exist in sickle cell disease patients with a normal ejected left ventricular fraction, compared to a control group of healthy patients.

The secondary goal of this study is to correlate, inside the sickle cell disease group, the possible strain anomalies with biological gravity parameters of the disease.