[Impact of anemia and its treatment in patients with acute coronary syndromes].

Anemia has been reported in 15-30% of patients with acute coronary syndrome. This percentage is even higher during the in-hospital phase, when hemoglobin tends to reach a "nadir" value, and usually a larger number of anemic patients compared to admission are discharged from the hospital. Both retrospective evaluation of randomized clinical trials and data coming from prospective or retrospective observational studies have prompted out a direct relationship between anemia and adverse outcomes in acute coronary syndrome patients. Although anemia has the potential to worsen the myocardial ischemic insult in acute coronary syndromes, it is not yet clear whether it is responsible per se for a higher incidence of death and myocardial infarction or it behaves just like an additional risk factor. Blood transfusions may correct anemia but also accentuate rather than attenuate both short-term and long-term rates of major adverse cardiac events, suggesting the opportunity of a restrictive use of this therapy in patients with low levels of hemoglobin who are hemodynamically stable.