New Hemolysis Parameters in Sickle Cell Disease

Study Overview
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Brief Summary
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The 6-minute walk (6MWT) test is used in adults and children affected by a wide range of chronic diseases to evaluate their sub-maximal exercise capacity. It reflects the global response of various physiological systems (respiratory, cardio-vascular, neurologic, metabolic and musculosquelettic) in a situation simulating a daily life activity. In children with sickle cell disease, the 6MWT is correlated with a low level of hemoglobin, a low level of fetal hemoglobin and low red cell deformability. Our team previously reported that in a population of children with sickle cell disease, highly treated with hydroxyurea, the sole factor which was independently linked to the 6MWT was the presence of silence infarct. As the cardio-vascular and cerebro-vascular injury in sickle cell disease are directly correlated with hemolysis, the investigators aim to evaluate a) the clinical relevance of endothelial and inflammation parameters and new hemolysis markers and b) if the presence of silent infarct and the 6MWT are correlated with this biological markers. This cross-sectional study will include sickle cell disease patients regularly followed for more than 5 years at Hôpital Universitaire des Enfants Reine Fabiola, Centre Hospitalier Universitaire (CHU)-Brugmann, Centre Hospitalier Etterbeek-Ixelles, CHU Saint-Pierre, Cliniques Universitaires Saint-Luc (Bruxelles, Belgium). Inclusion criteria are: sickle cell disease (SS, Sbeta°, SC, Sbeta+), age range : 6 to 25 years, signed informed consent. Exclusion criteria are: transplanted patients, inability to perform the 6MWT (severe cognitive disability, femoral osteonecrosis with functional impairment), hospitalization and/ or transfusion in the last 3 months for acute event. Demographic data and clinical data will be retrospectively recorded. Blood test and 6MWT will be performed in steady state. Studied analysis will be: coagulation factors, free hemoglobin, Pro-B type natriuretic peptide (Pro-BNP), High sensitivity C reactive protein (HS-CRP), Intercellular Adhesion Molecule (ICAM), Vascular Cell Adhesion Molecule (VCAM) and Selectins. With this study, the investigators expect to validate new predictive markers for cardio-vascular or cerebrovascular injury and to identify patients at high risk to develop these complications.

Official Title
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Evaluation de la capacité Physique Sous Maximale au Moyen du Test de Marche de 6 Minutes Des Enfants et Adultes Jeunes Suivis Pour drépanocytose et Nouveaux paramètres d'hémolyse : Vers Une prédiction Des Complications Vasculaires ?

Conditions
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Sickle Cell Disease

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Sickle Cell Disease (HbSS, S beta°, S beta+, SC) Regular follow-up from more than 5 years Written informed consent Exclusion Criteria: Transplanted patients Hospitalisation for an acute event within 3 months Acute transfusion within 3 months Unable to performed 6-minute walk test

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 25 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between new biological data and clinical phenotype | The primary outcome of this study is to validate the relationship between these new biological markers and the clinical phenotype. | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between new biological data and 6-minute walk test | The secondary outcome is to confirm the correlation between the 6-minute walk test and the presence of silent infarct and to explore the relationship between these new markers and the 6-minute walk test. | 2 years |