TCD screening, treatment reduced first overt stroke in childhood SCD

50th ASH Annual Meeting

Transcranial Doppler ultrasonography screening and treatment reduced the rate of first overt stroke among children with sickle cell disease, according to data presented at the 50th Annual Meeting of the American Society of Hematology.

“We saw a remarkable reduction [in stroke], showing that this TCD screening program really works and has almost eliminated symptomatic stroke in our patients.,” Janet Kwiatkowski, MD, director of stroke studies at the Sickle Cell Center at the Children’s Hospital of Philadelphia, said during a press briefing.

Kwiatkowski and colleagues examined the effects of transcranial Doppler ultrasonography on the risk for stroke in children with sickle cell disease aged younger than 22 years. The researchers compared the incidence of first stroke in these patients between the 8-year period prior to TCD screening (n=475) and the 8-year period postscreening (n=530).

Reported events were categorized as overt stroke (ischemic or hemorrhagic), not overt stroke (other neurological event) or indeterminate. Patients were followed until stroke or neurological event, age 22, end of the 8-year period or until the last clinic date.

Overt stroke occurred in 21 patients from the prescreening group and two patients from the postscreening group. Three patients in the prescreening group and six in the postscreening group experienced other neurological events. Two events in the prescreening group and one in the postscreening group were considered indeterminate.

Overt stroke incidence was 0.67 per 100 person-years in the prescreening period compared with 0.06 per 100 person-years in the postscreening period (P≤.001). According to the researchers, the first stroke case postscreening was a 3.4-year-old child with anterior cerebral artery velocities ≥200 cm/s with no abnormal velocities in the internal or middle cerebral arteries (the vessels assessed in the Stroke Prevention Trial in Sickle Cell Anemia to determine stroke risk). The second stroke case was a child aged 1.2 years old who was not yet screened due to age younger than 2 years.

“One of the areas we can improve is looking at these TCD tests in children younger than 2 years to see if we can figure out what cutoff values for cerebral flow in infants predict that they’re at a high risk of stroke so that we don’t miss the youngest children who are developing stroke,” Kwiatkowski said. – by Stacey L. Adams

For more information:

• Kwiatkowski. #714. Presented at: 50th Annual Meeting of the American Society of Hematology; December 5-9, 2008; San Francisco.

The point of this study is several-fold: it includes utility of transcranial Doppler ultrasonography (TCD) at a single center to determine the overall incidence of stroke in children with sickle cell disease or sickle cell beta zero. The authors found that with repetitive TCD studies every three to six months in those with conditional results (170 cm/s to 199 cm/s), and within one to four weeks for children with abnormal results (<200 cm/s), they could successfully reduce the likelihood of stroke with neurological symptoms by employing chronic transfusion therapy in those with abnormal results. This study is important because it provides a strong basis for careful monitoring of children with sickle cell disease with the risk of stroke with TCD and perhaps other imaging studies to prevent strokes from occurring.

– Laurence A. Boxer, MD

HemOnc Today Editorial Board member

This is a seminal study because the authors have demonstrated the importance of regionalization for health care for children with sickle cell disease. The children in this study received expert medical care from the tertiary care medical center and that includes not only a pediatric hematologist but also a pediatric neurologist. The results of this study set the standard that within a tertiary medical center using regular TCD assessments, we can expect that the rate of strokes will drop significantly when compared to the era prior to the use of TCD assessments.

– Michael R. DeBaun, MD, MPH

Professor of Pediatrics, Biostatistics and Neurology, Department of Pediatrics,

Washington University, St. Louis, Missouri