Friday, May 30, 2008

Blood Transfusion may do more harm than good?

DURHAM, N.C. – Heart patients are more than twice as likely to die during their first 30 days of hospitalization if they receive a blood transfusion to treat blood loss or anemia, according to a new analysis by cardiologists at the Duke Clinical Research Institute (DCRI)

Additionally, such patients are more than three times as likely to suffer a heart attack within 30 days, when compared to those who did not receive a transfusion.

These findings -- which emerged after a retrospective analysis of the treatments received by more than 24,000 patients hospitalized with an acute coronary syndrome -- run counter to earlier and smaller observational studies. For this reason, the researchers believe that a large randomized clinical trial needs to be initiated to resolve the issue and provide clear evidence-based guidance on how best to treat these patients.

According to Duke cardiologist Sunil Rao, M.D., lead author of a study, the causes underlying the increased incidence of adverse events after transfusion are unclear. Previous studies have shown that transfused blood increases oxygen delivery only in the most severely anemic patients. Also, nitric oxide is essential for delivery of oxygen from the hemoglobin in red blood cells to tissues. However, nitric oxide has a short half-life, so by the time stored blood has been transfused, the essential nitric oxide may have been depleted.

It is also possible, Rao continued, that the transfused blood may stimulate an immune response that can exacerbate already existing coronary artery disease.