A liberal blood transfusion strategy is safe in patients with myocardial infarction, anemia, and heart failure: lessons from MINT

Abstract Background In patients with acute myocardial infarction (MI) and anemia, the Myocardial Ischemia and Transfusion (MINT) trial found a trend toward increased 30-day death or recurrent MI with a restrictive compared with a liberal blood transfusion strategy. Patients with and without heart failure (HF) may respond differently to blood transfusion. Purpose To characterize the effects of restrictive vs. liberal transfusion strategies on clinical outcomes in patients with MI and anemia with and without baseline HF. Methods In the MINT trial, 3504 patients with MI and hemoglobin <10 g/dL were randomized to restrictive (7-8 g/dL) or liberal (10 g/dL) transfusion thresholds. We compared outcomes between patients with and without baseline HF, defined as any history of HF, acute HF, or baseline left ventricular ejection fraction (LVEF) <45%. Outcomes included death or incident HF, death or recurrent MI, death, and incident HF, all at 30 days. Results Compared with patients without baseline HF (n=1633), patients with baseline HF (overall n=1871 (history of HF n=1066, acute HF n=780, LVEF <45% n= 1099) were older, more frequently male and Black, and had higher rates of prior PCI, diabetes, and hypertension. In the restrictive strategy, patients with and without baseline HF received an average of 0.63 and 0.80 units of blood and had a median LOS of 6 and 4 days, respectively. In the liberal strategy, patients with and without baseline HF received an average of 2.44 and 2.49 units of blood and had a median LOS of 5 and 4 days, respectively. Patients with baseline HF had higher rates of death or incident HF (18.0% vs. 10.0%, risk ratio [RR]=1.79 [95% confidence interval {CI} 1.50-2.13]), death or recurrent MI (17.6% vs. 13.5%, RR=1.31 [95% CI 1.12-1.53]), and death (10.5% vs. 7.5%, RR 1.41 [95% CI 1.14-1.75]). Among patients with baseline HF, a restrictive transfusion strategy resulted in a trend toward an increase in death or HF and death or MI compared with a liberal transfusion strategy (Table, Figure). Among patients without baseline HF, the risk of incident HF was lower with restrictive than with liberal transfusion strategy. Conclusions Among patients with MI and anemia, a restrictive transfusion strategy resulted in a greater increase in death or HF, death or MI, and death in patients with baseline HF than in patients without baseline HF. A liberal transfusion strategy is safe for patients with MI and anemia, including those with prior or acute HF.TableFigure