Cerebrovascular Disease, Chuvash Polycythemia, Pulmonary Hypertension, Sickle Cell Anemia
Conditions
Keywords
6-Minute Walk, Chuvash Polycythemia, Echocardiogram, Sickle Cell Anemia, Pulmonary Function Tests, Sickle Cell Disease, SCD, Pulmonary Hypertension
Brief summary
The study will look at the risk factors for pulmonary hypertension (high blood pressure in the lungs) in children and adolescents with sickle cell anemia (SCA) and examine the role of hypoxia (oxygen shortage) in the disease. In patients with SCA, red blood cells become sickle-shaped and tend to form clumps that get stuck in blood vessels, blocking blood flow to the limbs and organs. Blocked blood vessels can cause pain, serious infections, and organ damage. Many patients with SCA also develop pulmonary hypertension. Children and adolescents with SCA or Chuvash polycythemia (another blood disorder that carries an increased risk for pulmonary hypertension) may be eligible for this study. Participants undergo the following procedures at the beginning (baseline) and end of the study: * History, physical examination and blood tests . * Echocardiography (ultrasound study of heart function). * Transcranial doppler (brain ultrasound study to measure brain blood flow). * Lung function tests. * 6-minute walk (measure of the distance covered in 6 minutes of walking). In addition, patients are followed by telephone or by clinic visits every 6 months for a review of their medical history and medications. A physical examination is also done at 12 months.
Detailed description
The research is designed to determine the prevalence and risk factors of pulmonary hypertension (PHT) in children and adolescents with sickle cell disease (SCD), and to determine the role of the hypoxic response in its pathogenesis. In this regard, proliferative vascular responses mediated by (i) hypoxia inducible factor (HIF)-regulated pathways and (ii) nitric oxide (NO)-scavenging will be compared between patients with SCD and patients with Chuvash polycythemia (CP), another hematological disorder characterized by increased risk for PHT. High throughput microarray and genotyping technologies will be employed to identify candidate gene pholymorphisms involved in pathologic responses to hypoxia in SCD and CP patients with and without PHT.
Interventions
None listed
Sponsors
National Heart, Lung, and Blood Institute (NHLBI)
Study design
Time perspective
OTHER
Eligibility
Sex/Gender
ALL
Age
3 Years to 20 Years
Healthy volunteers
Yes
Inclusion criteria
* INCLUSION CRITERIA A. For PAH in children and adolescents with SCD: Inclusion criteria for all participants: 1. The informed consent has been signed by the participant, parent or legal guardian as appropriate. 2. Age of 3 to 20 years. Inclusion criteria for SCD patients: 1. Diagnosis of sickle cell disease (electrophoretic HPLC documentation of SS, SC, Sb thalassemia or other major sickling phenotype such as SD, SO-Arab or SLepore is required). 2. At least three weeks has elapsed since hospitalization for acute chest syndrome, pain crisis, infection or other complication of SCD. 3. Absence of acute infection, pain crisis, or other acute complication of SCD. (Chronic SCD complications such as stuttering priapism, stable chronic pain and leg ulcers are not reasons for exclusion.) Inclusion criteria for control participants: 1. Self-described race is African American. 2. Absence of diagnosis of SCD as defined above and subsequent electrophoretic or HPLC documentation. 3. Absence of acute infection, injury, surgery or asthmatic episode.
Countries
Russia, United States
Outcome results
None listed