Comparison of Two Methods of Transfusion for Stroke Prevention in Sickle Cell
Comparison of Two Methods of Transfusion for Stroke Prevention in Sickle Cell
Chronic blood transfusions are essential supportive care for sickle cell patients at high
 risk for morbidity and mortality due to stroke. These patients, however, are at risk for iron
 overload. In the investigator's comprehensive sickle cell center, the investigators support
 chronic transfusion with rapid manual partial exchange transfusions (RMPET) using a single
 access central line port. The investigators do not have a comprehensive adult sickle cell
 program but upon transition of patients the patients would be provided simple transfusion
 (ST) in an adult ambulatory infusion setting due to nursing acuity needed for RMPET. The
 investigators plan to study the institution's participants currently on chronic transfusion
 support and compare different transfusion modalities to better understand the effects from
 switching from RMPET to ST. To date, there are no such comparisons within and between sickle
 cell patients in the literature.
II. Objective. Compare differences in RMPET versus ST.

 III. Specific Aims:

 1. To compare key predictive hematologic factors (hematocrit, hemoglobin, hemoglobin S
 quantification, blood volume and alloantibodies) for relative risk of stroke utilizing
 two methods of blood transfusion therapy.

 2. To determine the nursing time to administer straight versus manual exchange transfusion
 therapy.

 3. To survey patient satisfaction for both procedures.

 IV: Background/Significance:

 Stroke occurs in 10% of Sickle Cell Disease (SCD) patients before the age of 20 Years.
 Current standard of care for secondary overt stroke prevention in patients with SCD is
 chronic red blood cell (RBC) transfusions. Stroke recurs in ~ 60% of patients without chronic
 RBC therapy and in ~ 20% of patients with chronic transfusion while maintaining a hemoglobin
 S percentage of less than 30%. Indefinite transfusion therapy is practiced as discontinuation
 after short-term or long-term prophylactic transfusions leads to recurrent overt strokes and
 more ensuing CNS damage, even with transition to hydroxyurea. Chronic transfusions also
 prevent initial stroke in high-risk patients identified by transcranial Doppler (TCD)
 ultrasound. The Stroke Prevention Study in Sickle Cell Disease (STOP) demonstrated a 92%
 stroke risk reduction among 63 of 130 children with abnormal TCD results. Rates of stroke
 declined significantly since implementing routine TCD screening and primary prophylactic
 transfusion therapy. The subsequent STOP 2 trial supports the use of chronic transfusion
 indefinitely because discontinuation resulted in an increased rate of abnormal TCD conversion
 and development of overt stroke. Discontinuing transfusions on the STOP 2 trial was also
 associated with a higher occurrence of silent cerebral infarcts, documented in 3 of 37
 patients (8.1%) in the continued-transfusion group compared with 11 of 40 (27.5%) in the
 transfusion-halted group. More recent studies demonstrate that SCD patients are also at risk
 for silent cerebral infarcts. An association between worsening vasculopathy shown by magnetic
 resonance angiography and progressive overt and silent infarcts on magnetic resonance imaging
 has been found. More aggressive magnetic resonance imaging screening may be indicated and
 this could result in more patients with SCD treated with chronic transfusion.

 Common chronic transfusion modalities include ST or RMPET. The goal of therapy is to reduce
 the hemoglobin S level either by diluting the blood (ST) or by removing and replacing the
 blood with non-sickle hemoglobin (RMPET). To prevent further brain injury, the goal of
 transfusion therapy is to lower the hemoglobin S quantification to less than 30% on a routine
 basis, usually monthly transfusion procedure. There are many large centers that utilize
 erythrocytapheresis which is considered the preferable method if available.

 The investigator's study will focus on the types of RBC exchange therapy currently utilized
 in the investigator's Infusion Clinic at T.C. Thompson Children's Hospital. The investigators
 will determine which transfusion method is best for each participant for achieving the
 hematologic parameters of lower hemoglobin S quantification.The investigators will also
 measure the amount of nursing time for each procedure and which method is preferred by
 participants. The investigators will share the institutional observations with other
 institutions who may intend to switch between RMPET and ST.

 V. Methods:

 Study Design: Prospective observational cohort study

 The investigators will utilize the institution's current population of 8 eligible chronically
 exchanged transfused participants at the T.C. Thompson Children's Infusion Clinic. The
 eligible participants will be invited to participate in a cross over design study so that
 each participant serves as its own control. Eight participants will be randomly assigned
 (blinded envelope) whereby four participants will start with rapid manual partial exchange
 transfusion: 3 months will be spent in a wash out period, then 3 months of data collection
 for RMPET. This group will then be switched to simple transfusion with a wash out period of
 three months, then data collection for three months. The second group of four participants
 will start with simple transfusion and have an identical study design over 12 months (3
 months of collected data during simple transfusion, a 3 month wash out period, switch to
 rapid manual partial exchange transfusion for three months, then 3 months of data collection
 for RMPET).

 The investigators will optimize all therapy to achieve the post transfusion goal of <30%
 hemoglobin S and post transfusion Hb <12g/DL.with each transfusion performed for best
 practice in avoiding sickle cell complications.
Inclusion Criteria:

 1. Participants between 3 and 25 years of age

 2. Diagnosis of Hemoglobin SS or SBeta thalassemia

 3. On chronic exchange for stroke prevention

 4. Performance status: Lansky play score of 100%, and if over 16 years of age,
 Karnofsky=100%

 Exclusion Criteria:

 1. Participant has experienced more than one stroke and has a modified Rankin Scale of
 >3.

 2. Diagnosis of Hemoglobin SC disease

 3. Participants on chronic transfusion for priapism.