MONDAY, June 24 (HealthDay News) -- A new study suggests that an increase in blood transfusions for patients with sickle cell disease may have caused a drop in the number of black children suffering from ischemic strokes -- attacks brought about by a blockage in an artery.

Black children, however, still have a much greater risk of death from hemorrhagic (bleeding) strokes than white children, the new study finds.

Sickle cell disease gets its name from the shape of the red blood cells in someone who has it. They're crescent-shaped, similar to a farm tool called a sickle. These abnormally shaped red blood cells become hard and sticky and can clog the blood vessels, creating pain, according to the U.S. Centers for Disease Control and Prevention.


In the new study, researchers led by Dr. Laura Lehman of Boston Children's Hospital analyzed U.S. death certificate data for all children who died from 1988 through 2007. There were more than 4,400 deaths attributed to stroke, an average of 221 per year.

Twenty percent of the stroke deaths were caused by ischemic stroke, 67 percent by hemorrhagic stroke and 12 percent were unspecified, according to the study, which was published online June 26 in the journal JAMA Pediatrics.

In the period between 1988 and 1997, black children were 74 percent more likely to die from an ischemic stroke compared to white children, but that relative risk fell to 27 percent during the period from 1998 to 2007, the researchers found.

The relative risk for hemorrhagic stroke death, however, rose slightly over the same time period. From 1988 to 1997, black children were 90 percent more likely than whites to die from this type of "bleeding" stroke, and that number rose to 97 percent from 1998 to 2007.

"The excess risk of death from ischemic, but not hemorrhagic, stroke in U.S. black children has decreased over the past decade," the study authors wrote. "The only major change in childhood stroke care during this period was the initiation of long-term blood transfusion therapy for primary stroke prevention in sickle cell disease."

Two experts agreed that the change in the frequency of blood transfusions for children with sickle cell disease -- which predominantly affects blacks -- is driving the trend toward fewer ischemic strokes in black children.

The practice of giving sickle cell patients blood transfusions "occurred as a result of the STOP study, published in 1998," said Dr. Winfred Wang, a sickle cell expert at St. Jude Children's Research Hospital in Memphis, Tenn. "In this trial, ischemic stroke was reduced by 90 percent by placing children on chronic transfusion if they were at high risk for stroke, based on [ultrasound] screening of blood flow in cerebral arteries."

"This intervention has had a profound effect on the welfare of children with this condition," Wang said.

Dr. Rafael Alexander Ortiz, director of neuro-endovascular surgery and stroke at Lenox Hill Hospital in New York City, agreed with Wang that the new study "demonstrated the long-term effectiveness and results after implementation of blood transfusions as a preventive measure for children with sickle cell disease."

More information

The Nemours Foundation has more about strokes and children.