A simple index using age, hemoglobin, and aspartate transaminase predicts increased intracerebral blood velocity as measured by transcranial Doppler scanning in children with sickle cell anemia.
OBJECTIVE
Increased intracerebral blood velocity measured by transcranial Doppler scanning identifies children with sickle cell anemia who are at increased risk of stroke. We have tried to develop an index based on routine clinical measurements that also predicts increased intracerebral blood flow.


METHODS
Routinely collected clinical and laboratory data were correlated with transcranial Doppler measurements on children with sickle cell anemia seen in a single institution in 2006. The index produced was validated on a second independent data set from children with sickle cell anemia.


RESULTS
The time-averaged mean of the maximum velocity in centimeters per second in the middle cerebral artery circulation correlated significantly with age, hemoglobin, lactate dehydrogenase, and aspartate transaminase levels, white blood cell count, and creatinine level. On multiple regression, hemoglobin and aspartate transaminase levels maintained their significance, whereas age had borderline significance, and an index was developed linked to a time-averaged mean of the maximum velocity of 220 - (8 x hemoglobin) - (1.4 x age) + (0.4 x aspartate transaminase). This detected a time-averaged mean of the maximum velocity of >170 cm/second with 100% sensitivity and 58% specificity. The index was validated on the second data set and again showed 100% sensitivity with 73% specificity.


CONCLUSIONS
This simple index has the potential to identify children who are at higher risk of cerebrovascular disease to allow them to be prioritized for transcranial Doppler scanning and other intracerebral imaging.
Rees
David C
DC
Department of Haematological Medicine, King's College Hospital, Denmark Hill, London SE5 9RS, United Kingdom. david.rees@kcl.ac.uk
Dick
Moira C
MC
Height
Sue E
SE
O'Driscoll
Sandra
S
Pohl
Keith R E
KR
Goss
David E
DE
Deane
Colin R
CR
D000293:Adolescent; D000367:Age Factors; D000755:Anemia, Sickle Cell / Q000097:blood* / Q000503:physiopathology*; D001219:Aspartate Aminotransferases / Q000097:blood*; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D011237:Predictive Value of Tests; D017585:Ultrasonography, Doppler, Transcranial
D006454:Hemoglobins; D001219:Aspartate Aminotransferases