December 15, 2011

‘Silent strokes’ in children with sickle cell disease investigated

‘Silent strokes’ in children with sickle cell disease investigated

Vanderbilt researchers, as part of a multicenter study, have found that children who have sickle cell disease along with high blood pressure and anemia are at an increased risk for silent strokes.

Michael DeBaun, M.D., vice chair for Clinical Research for Vanderbilt’s Department of Pediatrics, is the principal investigator of the ongoing Silent Cerebral Infarct Transfusion (SIT) Trial, an international study involving 25 sites.

Michael DeBaun, M.D.

Michael DeBaun, M.D.

The $18 million, NIH-funded SIT trial is the largest study to date on children with sickle cell.

Strokes in children are rare, but are a more common neurologic condition of children with sickle cell.

A silent stroke is a permanent injury to the brain that affects children’s ability to think. Often, these children show no overt symptoms.

Silent stroke can affect their academic performance and their ability to perform tasks. Generally, people who suffer silent stroke have a drop in IQ of about eight points.

MRI results of the brain from this portion of the study revealed that one-third (31 percent) of 814 children with sickle cell disease, ages 5 to 15, had suffered silent strokes.

Researchers found that either anemia (low hemoglobin) or high blood pressure alone increased a child’s chance for stroke. But children with both risk factors had a four-fold risk of silent stroke.

Their report was published in the journal Blood online.

“Anemia and hypertension are risk factors for silent strokes in this patient population, and having both is a major risk factor,” said DeBaun, lead author of the report and director of the Vanderbilt-Meharry-Matthew Walker Center for Excellence in Sickle Cell Disease.

“We need to identify therapies to prevent silent strokes from occurring in this patient population, as children with silent strokes are disproportionately affected.”

DeBaun said the findings provide the strongest evidence to date that health providers could potentially modify the risks of silent strokes.

The data, he said, also set up preliminary evidence that was used to support a newly funded, multicenter National Institute of Health study of the drug hydroxyurea, known to increase the hemoglobin level.

The trial will identify infants with sickle cell disease who have no evidence of silent strokes.

They will be selected randomly to receive the drug, and monitored over a three-year period to determine if the medication helps prevent silent stroke.

Other Vanderbilt researchers for this new trial include Laurie Jordan, M.D., Ph.D., pediatric neurologist, Maureen Sanger, Ph.D., nurse psychologist, Jackie Harris, research nurse, Marta Schumann, M.D., radiologist, and Ira Landsman, M.D., anesthesiologist.

Nearly 100,000 people in the United States are living with sickle cell disease, a group of inherited red blood cell disorders.

The disease most commonly affects the African-American population, occurring in one of every 400 births.