Please select the eligibility criteria that correspond to the clinical trial below.
Title: N/A
Brief Summary: To determine how long blood transfusions are needed for primary stroke prevention. Also, to determine the duration of risk associated with abnormal transcranial Doppler ultrasound (TCD) and to determine the specificity of the stroke risk model developed in STOP 1 in patients with abnormal TCD measurements.


Options:
A: Inclusion Criteria for the Observational and Trial Cohorts:

* Hemoglobin diagnosis of SS (two copies of the hemoglobin S gene), SC (one copy of the hemoglobin S gene and one copy of the hemoglobin C gene), or S-β thalassemia (β+ or β0)
* No clinically apparent ACS
* No prior participation in either part of the study

Inclusion Criteria for the Trial Cohort, in addition to the above criteria:

* sPLA2 level greater than 100 ng/mL within the same 24-hour window that coincides with fever and chest radiograph negative for new pulmonary infiltrate within the last 12 hours of the 24-hour window
* Fever greater than 38.0º C within the same 24-hour window that coincides with elevated sPLA2 level (greater than 100 ng/mL) and chest radiograph negative for new pulmonary infiltrate within the last 12 hours of the 24-hour window
* Chest radiograph negative for new pulmonary infiltrate within the last 12 hours of the 24-hour window of an abnormal sPLA2 level and fever
* Hemoglobin levels equal or less than 10 g/dL at time of study entry
* Informed consent of parent(s) or legal guardian; informed consent or assent of participant as applicable

Exclusion Criteria for Observational and Trial Cohorts:

* Existing diagnosis of a new pulmonary infiltrate diagnosed by chest radiography (pleural effusion not obscuring lung parenchyma will not exclude the person from the study)
* Any coexisting medical condition for which the physician feels that a transfusion may be needed within 24 hours (e.g., severe anemia, stroke)
* Red Blood Cell (RBC) transfusion in the 60 days before study entry
* Unwillingness to sign consent form, or if a minor, unwillingness of parent/guardian to sign consent form
* Treatment with any investigational drug or device in the 30 days before study entry (hydroxyurea is allowable)
* History of alloimmunization that would prevent the participant from receiving blood within 8 hours of eligibility for study entry or history of a life-threatening transfusion reaction
* Objection to transfusion for religious or other reasons from either the participant or guardian
* History of treatment with systemic steroids within 1 week of study entry (inhaled steroids are acceptable)
* Pregnant
B: Inclusion Criteria:

* Have SCD \[homozygous sickle cell (HbSS) or hemoglobin (HbS) Beta\^0 thalassemia\]
* Are participants with SCD who have had ≥2 episodes of vaso-occlusive crisis (VOC) in the past year
* Have a body weight ≥19 kilograms (kg) and are ≥2 and \<18 years of age, inclusive at the time of screening
* If participants are ≥2 and ≤16 years of age, must have had a transcranial Doppler within the last year

Exclusion Criteria:

* History of: transient ischemic attack (TIA)/ ischemic or hemorrhagic stroke, severe head trauma, intracranial hemorrhage, intracranial neoplasm, arteriovenous malformation, or aneurysm
* History of abnormal or conditional \[velocity in middle or anterior cerebral, or internal carotid artery ≥170 centimeter per second (cm/sec)\] transcranial Doppler within the last year
* History of, or are undergoing treatment with, chronic red blood cell (RBC) transfusion therapy
* Are at an increased risk for bleeding complications
* Are receiving chronic treatment with nonsteroidal anti-inflammatory drug (NSAID)s and cannot be switched to another analgesic
C: INCLUSION:

* Patient must have sickle cell anemia (hemoglobin SS) or sickle beta thalassemia (hemoglobin SB) as confirmed at the local institution.
* Participating institutions must submit documentation of the diagnostic hemoglobin analysis to the Statistical and Clinical Coordinating Centers to confirm the diagnosis of sickle cell anemia prior to randomization.
* Patient must be 5 through 14 years of age.
* Patient must have a cerebral infarct documented by MRI scan as read by the neuroradiology panel.
* Informed consent with assent in accordance with the institutional policies (institutional Institutional Review Board approval) and Federal guidelines (approved by the United States Department of Health and Human Services) must be signed by the patient's legally authorized guardian acknowledging written consent to join the study. When suitable, patients will be requested to give their assent to join the study.

EXCLUSION:

* Patient with a history of a focal neurologic event lasting more than 24 hours with medical documentation or a history of prior overt stroke.
* Patients with a transcranial doppler (TCD) study with a time-averaged mean velocity greater than 200 cm/sec verified by the study radiologist.
* Patients with other neurological problems, such as neurofibromatosis, lead poisoning, or tuberous sclerosis.
* Patients with HIV infection.
* Pregnancy.
* Patients who received treatment with anti-sickling drugs or hydroxyurea within 3 months or anticipate receiving anti-sickling drugs or hydroxyurea during the course of the study.
* Abnormal kidney function (creatinine \> 2x upper limit of normal).
* Patients on chronic blood transfusion therapy for other reasons.
* Patients judged not likely to be compliant by his/her hematologist and local nurse coordinator based on previous compliance in clinic appointments and following advice. Specifically, families that have missed at least two appointments without notification within 12 months prior to the trial or parents of potential patients that have been reported for medical or education neglect are not eligible for this trial.
* Patients unable to receive blood transfusion because of alloimmunization.
* Patients with permanent or semi-permanent metallic (braces on teeth) structures attached to their body. Such patients cannot obtain a MRI of the head to assess the presence of silent cerebral infarcts.
* Siblings randomized in the trial.
D: No eligibility criteria

Answer: D