Regular blood transfusions to prevent a stroke in people with sickle cell disease

Hirst C, Wang WC

Published Online:

October 7, 2009

In sickle cell disease there are fewer red blood cells. This means less oxygen is carried to tissues and there are problems throughout the body. Sickled red blood cells can block blood vessels in the brain, leading to strokes. We aimed to compare long-term blood transfusion schedules to other transfusion schedules or other ways of preventing stroke. There are two trials in the review. The results showed that regular blood transfusions reduce the risk of stroke significantly by diluting sickled cells. There are important adverse effects (iron overload, infection transmitted through blood and reactions to the transfusions). When the treatment stopped, people returned to having a high risk of stroke. This may be the same level of risk as at the start of transfusion. When using this treatment the burden of long-term transfusion should be weighed against the degree of risk of stroke. Further research should look at using transfusion to prevent secondary stroke and defining further risk factors for stroke. This would avoid starting children on blood transfusions if these are not needed.

Abstract (click to read)

Background:

In sickle cell disease (SCD), a common inherited haemoglobin disorder, abnormal haemoglobin distorts red blood cells, causing anaemia, vaso-occlusion and dysfunction in most body organs. Stroke affects around 10% of children with sickle cell anaemia and recurrence is likely. Chronic blood transfusion dilutes the sickled red blood cells, reducing the risk of vaso-occlusion and stroke. However, side effects can be severe.

Objectives:

To assess risks and benefits of chronic blood transfusion regimens in people with SCD to prevent first stroke or recurrences.

Search strategy:

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register, comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and conference proceedings.

Last search of the Group's Trials Register: 22 May 2009.

Selection criteria:

Randomised and quasi-randomised controlled trials comparing blood transfusion as prophylaxis for stroke in people with SCD to alternative or no treatment.

Data collection and analysis:

Both authors independently assessed trial quality and extracted data.

Main results:

Searches identified two eligible trials. One compared a chronic transfusion regimen for maintaining sickle haemoglobin lower than 30% with standard care in 130 children with SCD judged (through transcranial doppler ultrasonography) as high-risk for first stroke. During the trial, 11 children in the standard care group suffered a stroke compared to one in the transfusion group. This 92% relative risk reduction meant the trial was terminated early. Thirty months treatment was planned, but median follow up was 21.1 months. The transfusion group had a high complications rate: iron overload; alloimmunisation; and transfusion reactions. The second trial investigated risk of stroke when transfusion was stopped after at least 30 months. The trial closed early due to a significant difference in risk of stroke between participants who stopped transfusion and those who continued (for whom it was deemed unsafe to recommend discontinuation), as measured by abnormal velocities on Doppler examinations, OR 0.02 (95% CI 0.00 to 0.43). No trials were identified investigating transfusion for preventing recurrence of stroke.

Authors' conclusions:

These trials demonstrated a significantly reduced risk of stroke in participants receiving regular blood transfusions. Data from a follow-up trial indicate individuals may revert to former risk status if transfusion is discontinued. Degree of risk must be balanced against the burden of chronic transfusions. Further research is required examining the use of transfusion in preventing secondary stroke, and further defining risk factors for stroke, to avoid unnecessarily starting children on blood transfusions.

This record should be cited as:

Hirst C, Wang WC. Blood transfusion for preventing stroke in people with sickle cell disease. Cochrane Database of Systematic Reviews 2002, Issue 1. Art. No.: CD003146. DOI: 10.1002/14651858.CD003146

Assessed as up to date:

June 12, 2009

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Primary Review Group:

Cystic Fibrosis and Genetic Disorders Group

Health topics:

Blood disorders > Genetic disorders > Sickle cell disease: blood transfusion

Genetic disorders > Sickle cell disease > Blood transfusion

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Independent high-quality evidence for health care decision making

Regular blood transfusions to prevent a stroke in people with sickle cell disease

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