Receiving a blood transfusion is associated with a greater risk of death for patients with acute coronary syndromes

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.