Sickle Cell Disease
Conditions
Brief summary
Sickle cell disease (SCD) affects haemoglobin - the molecule in blood cells which carries oxygen. It causes red blood cells to become abnormal crescent (or sickle)- shaped. Sickled red blood cells cannot travel through small blood vessels as easily as normal red blood cells which can lead to blockages. This means that oxygen may be prevented from getting to where it is needed. Individuals with sickle cell disease also suffer form abnormality in the lining of their blood vessels, which contributes to the damage. Damage and blockage can occur in the blood vessels in the brain and means that children with sickle cell disease have a significant risk of suffering from strokes. Research has shown that transcranial Doppler ultrasonography can be used in this setting to identify children at most risk of getting strokes. Ultrasound is therefore used in children with sickle cell disease to measure the blood flow in the vessels in the brain. This research has formed the basis of the National Health Service (NHS) Standard of Care for Sickle Cell Disease in the United Kingdom (UK) which uses transcranial Doppler ultrasonography at once a year to screen children with sickle cell disease aged 2 to 16. Ultrasound is used because it is portable, does not uses ionising radiation such as x-rays, is non-invasive and gives good results. However, the results are dependent on the operator. This means that the screening service is provided by centres of excellence with experienced scanning staff visiting clinics in smaller hospitals with portable machines. There is a lack of research comparing the use of portable machines to laboratory-based machines. This is important because screening can identify children at high risk of stroke and may be used by clinical staff to make a decision about the care of the child.
Detailed description
Please see above
Interventions
OTHERUltrasound scan
Trans cranial Doppler ultrasound examination of cerebral arterial blood flow
Sponsors
Imperial College London
Imperial College Healthcare NHS Trust
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
2 Years to 16 Years
Healthy volunteers
No
Inclusion criteria
* Clinical Diagnosis of Sickle Cell Disease * Under surveillance as part of the NHS Sickle Cell & Thalassaemia Screening Programme * Children between the ages of 2 - 16 years old. Those under 16 years of age must be accompanied by a responsible adult.
Exclusion criteria
* Participants older than 16 years of age as this is outside the scope of the sickle cell screening programme. * Individuals unable to give fully informed and voluntary consent. * Individuals with inadequate temporal windows as it will not be possible to record measurements of velocity.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Measurement of Time Average Mean of the Maximum (TAMM) in cm/Sec in Cerebral Arteries Using 2 Different Ultrasound Machines. | 4 months | A flow phantom was used to compare Time average mean maximum velocity measurements from a Philips IU-22 and Zonare Z-One ultrasound machine. 25 children with SCD (aged 2-15 years) attending the outpatient clinic at St. Mary's Hospital, Imperial College Healthcare NHS Trust as part of the NHS Sickle Cell & Thalassaemia (SC&T) screening programme, were studied. The Time Averaged Mean of the Maximum (TAMM) velocities in the middle cerebral artery (MCA) and stroke risk categorisation using the two ultrasound machines were compared. |
Countries
United Kingdom
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Ultrasound Scan in Ages 2-16 Years Children aged 2-16 years of age with Sickle Cell Disease and under the care of consultant haematologist as part of the NHS screening programme.
Ultrasound scan: Trans cranial Doppler ultrasound examination of cerebral arterial blood flow | 25 |
| Total | 25 |
Baseline characteristics
| Characteristic | Ultrasound Scan in Ages 2-16 Years | — |
|---|---|---|
| Age, Categorical <=18 years | 25 Participants | — |
| Age, Categorical >=65 years | 0 Participants | — |
| Age, Categorical Between 18 and 65 years | 0 Participants | — |
| Race and Ethnicity Not Collected | — | — Participants |
| Region of Enrollment United Kingdom | 25 participants | — |
| Sex: Female, Male Female | 14 Participants | — |
| Sex: Female, Male Male | 11 Participants | — |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 25 |
| other Total, other adverse events | 0 / 25 |
| serious Total, serious adverse events | 0 / 25 |
Outcome results
Primary
Measurement of Time Average Mean of the Maximum (TAMM) in cm/Sec in Cerebral Arteries Using 2 Different Ultrasound Machines.
A flow phantom was used to compare Time average mean maximum velocity measurements from a Philips IU-22 and Zonare Z-One ultrasound machine. 25 children with SCD (aged 2-15 years) attending the outpatient clinic at St. Mary's Hospital, Imperial College Healthcare NHS Trust as part of the NHS Sickle Cell & Thalassaemia (SC&T) screening programme, were studied. The Time Averaged Mean of the Maximum (TAMM) velocities in the middle cerebral artery (MCA) and stroke risk categorisation using the two ultrasound machines were compared.
Time frame: 4 months
| Arm | Measure | Group | Value (MEAN) |
|---|---|---|---|
| Ultrasound Scan in Ages 2-16 Years | Measurement of Time Average Mean of the Maximum (TAMM) in cm/Sec in Cerebral Arteries Using 2 Different Ultrasound Machines. | Philips IU-22 | 120 cm/sec |
| Ultrasound Scan in Ages 2-16 Years | Measurement of Time Average Mean of the Maximum (TAMM) in cm/Sec in Cerebral Arteries Using 2 Different Ultrasound Machines. | Zonare Z-One | 120 cm/sec |