PEDIATRICS Vol. 111 No. 3 March 2003, pp. 710-711
Health Supervision for Children With Sickle Cell Disease
To the Editor.—I applaud the AAP Section on Hematology/Oncology and Committee on Genetics for authoring a comprehensive statement on health supervision for children with sickle cell disease.1 Understandably, the statement weakly endorses screening tests not supported by evidence, such as chest radiography, echocardiography, or pulmonary function tests. However, transcranial Doppler ultrasound screening received an equally equivocal endorsement, concluding that it "may be indicated." Because the evidence for this screening test is quite strong, I do not understand the reasoning behind such a weak recommendation.
As the authors note, transcranial Doppler predicts the risk of stroke for children with sickle cell disease.2 Children with abnormal Doppler results who were randomized to receive chronic transfusion therapy had a 92% lower risk of stroke than those randomized to usual care.3 This finding resulted in the early termination of this trial and a clinical alert from the National Heart, Lung, and Blood Institute in 1997.4 This compelling evidence appears to merit a strong recommendation to screen children with sickle cell disease with transcranial Doppler.
As recommendations for pediatric health supervision continue to expand while health insurance benefits contract, pediatricians are forced to prioritize time and resources. Recommendations that are graded based on the quality of evidence may best inform these decisions.
Colin Sox, MD
Department of Pediatrics
University of Washington
Seattle, WA 98195-7183
REFERENCES
- American Academy of Pediatrics, Section on Hematology/Oncology and Committee on Genetics. Health supervision for children with sickle cell disease.
Pediatrics.2002; 109
:526
–535
[Abstract/Free Full Text] - Adams RJ, Nichols FT, Carl E, et al. The use of transcranial ultrasonography to predict stroke in sickle cell disease. N Engl J Med.1992; 326 :605 –610[Abstract]
- Adams RJ, Hsu L, Files B, et al. Prevention of a first stroke by transfusions in children with sickle cell anemia and abnormal results on transcranial ultrasonography.
N Engl J Med.1998; 339
:5
–11
[Abstract/Free Full Text] - National Heart, Lung, and Blood Institute. Clinical alert from the National Heart, Lung and Blood Institute [press release]. Bethesda, MD: National Institutes of Health. September 18, 1997
In Reply.—
Dr Sox correctly notes that screening with transcranial Doppler (TCD) ultrasonography identifies children with sickle cell disease (SCD) who are at high risk for developing a first stroke,1 and that chronic transfusions markedly reduce the risk of stroke in such high-risk patients.2 However, a number of important issues led us to withhold an unequivocal recommendation for the routine use of TCD screening and chronic transfusions for primary stroke prevention in SCD.
We agree with Dr Sox that there is good evidence of short-term benefit from TCD screening, but long-term risks and benefits are unclear. Chronic transfusions are associated with significant morbidity and some mortality from transfusion-related infections, alloimmunization, and hemosiderosis. As many as 70% of TCD-positive patients may never have a stroke if not transfused. Thus, TCD screening may expose more patients to significant risk than the number that benefit. Additional studies are needed to determine whether the predictive value of a positive TCD can be improved by other measures such as magnetic resonance imaging (MRI), MRA, or neurocognitive testing. The duration of chronic transfusions needed for primarily stroke prevention in high-risk patients is unknown and the subject of an ongoing prospective clinical trial.
Given these uncertainties, there is considerable controversy about the NIH Clinical Alert that recommended TCD screening.3 Results from a clinical practice survey conducted in March 20014 showed that only 36% of pediatric hematologists/oncologists who treat children with SCD strongly recommended chronic transfusions as the best treatment option for a child with a confirmed elevated TCD velocity. The other 64% would discuss published TCD results with the family and base clinical decisions in part on other factors including MRI/MRA results, neurocognitive testing, family history, history of severe complications of SCD, and/or predicted family compliance with transfusions. At our own institutions, the implementation of TCD screening and the clinical approach to children with positive results varies widely.
Finally, pediatricians should be aware that standardization of TCD screening may be problematic. The TCD procedures used in the STOP study2 were performed by technicians, trained at a single center, who used a standardized protocol with identical equipment. TCD results obtained by others using more widely available ultrasonography equipment have shown differences. Thus, unless the procedure is carefully standardized, measurement of blood velocity will not necessarily be comparable to published studies.1,2 In March 2001,4 TCD was available locally to 79% of pediatric hematologists/oncologists who care for patients with SCD, but 27% of them were not confident that the results were reproducible and interpretable.
Hopefully, new data will clarify the remaining issues and support a consensus on the use of TCD screening and chronic transfusions for primary stroke prevention in SCD. Until then, we feel it would be premature for the AAP to unequivocally recommend routine TCD screening for all children with SCD.
AAP Ad Hoc Writing Committee: Peter A. Lane, MD, Chairperson
George R. Buchanan, MD
Franklin Desposito, MD
Charles H. Pegelow, MD
Elliott P. Vichinsky, MD
Doris L. Wethers, MD
Gerald M. Woods, MD
REFERENCES
- Adams RJ, McKie V, Nichols F, et al. The use of transcranial ultrasonography to predict stoke in sickle cell disease. N Engl J Med.1992; 326 :605 –610
- Adams RJ, McKie VC, Hsu L, et al. Prevention of first stroke by transfusions in children with sickle cell anemia and abnormal results on transcranial doppler ultrasonography. N Engl J Med.1998; 339 :5 –11
- National Heart, Lung, and Blood Institute. Clinical Alert from the National Heart, Lung, and Blood Institute [press release]. Bethesda, MD: National Institutes of Health. September 18, 1997
- Lane PA, Buchanan GR, Ware RE. Variable approaches to therapeutic options for children with sickle cell disease (SCD): a practice survey of the American Society of Pediatric Hematology/Oncology (ASPH/O) [abstract]. Blood.2001; 98 :784a
PEDIATRICS (ISSN 1098-4275). ©2003 by the American Academy of Pediatrics
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