Heart attack patients who receive a blood transfusion are at a much higher risk of death than those who don't receive one, according to a report published in Archives of Internal Medicine.
Anticoagulant and anti platelet drugs are often used to treat acute coronary syndrome which typically occurs during a heart attack. These drugs work effectively, but they also increase the patient's risk of bleeding, which can eventually develop into anemia, a condition that often results in the need for a blood transfusion.
A group of researchers led by Saurav Chatterjee, M.D., of Brown University, carefully analyzed ten studies carried out between January 1966 and March 2012 which involved a total of 203,665 patients.
The all-cause mortality rates of those who underwent a blood transfusion during myocardial infarction was found to be 8 percent higher than those who didn't receive one (18.2 percent vs 10.2 percent). This represents a significant increase in risk of mortality (by 12 percent) among those who received a blood transfusion.
Further analyses indicated that the increased risk of mortality among those who received a blood transfusion was independent of baseline and hemoglobin levels as well as any changes of hemoglobin levels. =
Those who had a blood transfusion were also found to be at a higher risk of suffering from another heart attack.
The authors said:
"In conclusion, this meta-analysis provides evidence that rates of all-cause mortality and subsequent myocardial infarction are significantly higher in patients with acute myocardial infarction receiving blood transfusion. Additional outcomes data are needed from randomized clinical trials that investigate important outcomes with adequate sample size and with low risk for bias."
Much more research is needed, according to Jeffrey L. Carson, M.D., of the University of Medicine and Dentistry of New Jersey, New Brunswick, and Paul C. Hébert, M.D., of the Ottawa Hospital Research Institute, Canada. They state that it is difficult to know whether or not more people suffering from myocardial infarction die from blood transfusions than anemia.
They add: "What might we take away from this systematic review? The authors remind us that patients with an acute myocardial infarction are often anemic and receive red blood cell transfusion. However, because of its many limitations, as physicians, we should not use the results of this review to justify or limit the use of red blood cells."
Carson and Hébert conclude:
"For researchers and decision makers, we can now appreciate how little reliable information is available to inform clinical and policy decisions involving red blood cell transfusions in patients with acute coronary syndrome.
Given that real risks and potential benefits exist as to how we choose to use the valuable resource of blood transfusion, we believe that high-quality research is long overdue."
Written by Joseph Nordqvist