Public release date: 5-Oct-2004
Contact: Richard Merritt
919-684-4148
Heart attack patients who receive blood transfusions have higher death rate
Receiving a blood transfusion is associated with a greater risk of death for patients with acute coronary syndromes, such as a myocardial infarction (heart attack), according to a study in the October 6 issue of JAMA.
The use of invasive procedures for treatment of ischemic heart disease has more than tripled in the past 2 decades and is likely to increase in high-risk patients, according to background information in the article. This, coupled with the widespread use of antithrombotic drugs, has increased the potential for bleeding and blood transfusion among patients with cardiovascular disease. Approximately 12 million units of blood are transfused to 3.5 million patients each year in the United States, and although transfusing blood to anemic patients with ischemic heart disease may theoretically increase oxygen delivery and improve outcomes, there is no definitive evidence to support such a practice, according to the article.
Patients hospitalized for an acute coronary syndrome (ACS) are at risk of developing anemia acutely as a consequence of bleeding. For clinical practice, a crucial issue is whether blood transfusion is beneficial or harmful for patients with ischemic heart disease who have developed anemia acutely during their hospitalization. Clinical studies have had differing results.
Sunil V. Rao, M.D., of the Duke Clinical Research Institute, Durham, N.C., and colleagues used clinical data from three large international trials of patients with ACS to determine the association between blood transfusion and outcomes among patients who developed moderate to severe bleeding, anemia, or both during their hospitalization. The study included 24,111 participants in the GUSTO IIb, PURSUIT, and PARAGON B trials. Patients were grouped according to whether they received a blood transfusion during hospitalization.
Of the patients included, 2,401 (10.0 percent) underwent at least 1 blood transfusion during their hospitalization. The researchers found that the rates for three outcomes (30-day death, heart attack, and composite death/heart attack) were significantly higher among patients who received a transfusion (30-day death, 8.00 percent for patients who received a transfusion vs. 3.08 percent for patients who did not; 30-day heart attack, 25.16 percent vs. 8.16 percent; 30-day composite death/heart attack, 29.24 percent vs. 10.02 percent). Blood transfusion was associated with a nearly four times increased risk for 30-day death and nearly three times increased risk for 30-day death/heart attack. In further analysis that included procedures and bleeding events, transfusion was associated with a trend toward increased risk of death.
"Given the disparity in results between our study and other observational studies of transfusion and outcome, a randomized trial of transfusion strategies in anemic patients with ACS is warranted to guide clinical practice. Until then, we caution against the routine use of blood transfusions to maintain arbitrary [certain blood measurement] levels in stable patients with ischemic heart disease," the authors write.
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(JAMA. 2004; 292:1555-1562. Available post-embargo at
www.jama.com)
Editor's note: This work was supported by the Duke Clinical Research Institute, Durham, N.C.
Editorial: Do Transfusions Get to the Heart of the Matter? In an accompanying editorial, Paul C. Hébert, M.D., M.H.Sc., and Dean A. Fergusson, Ph.D., of the Ottawa Health Research Institute, Ottawa, Ontario, Canada compare the results from Rao et al to that observed in other studies.
"… Rao et al only included younger individuals who required aggressive interventional management. It is plausible that a higher transfusion threshold would benefit elderly patients because of the greater degree of diffuse vascular disease, the presence of additional comorbid illnesses, and the inability to augment cardiac output as a means of compensation for anemia. Younger patients may derive less benefit from transfusions because of widespread use of aggressive revascularization procedures, statins, new antiplatelet agents, and other therapies that have been shown to save lives," they write.
"Observational studies such as the reports by Rao et al and [another study] do not provide unbiased estimates of the benefits of therapy when the degree of anemia is directly related to the administration of red blood cells. Given the complex interplay between the risks and benefits of anemia and transfusion in patients with ischemic heart disease, it is time to undertake randomized controlled clinical trials in different populations of patients with ischemic heart disease," they conclude. (JAMA. 2004; 292:1610-1612. Available post-embargo at
www.jama.com)
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Heart attack patients who receive blood transfusions have higher death rate
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