The use of a liberal transfusion strategy may be particularly impactful in type 1 myocardial infarction (MI) patients with anemia, according to a prespecified subgroup analysis of data from the MINT trial that reports a trend toward better outcomes. Findings were presented by Andrew P. DeFilippis, MD, MSc, from Vanderbilt University Medical Center, Nashville, Tennessee, on Sunday at the American College of Cardiology (ACC) 2024 conference in Atlanta, where he noted that anemia is common in patients with acute MI but that trial data on the efficacy of transfusion in such a patient population are “limited.” Speaking at ACC.24, DeFilippis said that the recently completed MINT trial addressed the treatment of patients with acute MI and anemia, adding that although findings from the MINT trial did not report a statistically significant difference in the rate of death or recurrent MI in patients with acute MI and anemia, the point estimate favored a liberal transfusion strategy. “Since type 1 (T1) and type 2 (T2) MI are distinct pathophysiological entities, we performed a prespecified subgroup analysis,” he noted. Study details DeFilippis noted that the MINT trial randomly allocated 3,504 patients with acute MI (Type 1,2, 4b or 4c) and hemoglobin (Hb)<10 g/dL to a restrictive (Hb threshold of 7 to 8 g/dL) or liberal (Hb threshold of 10 g/dL) transfusion strategies. The primary analysis from the study showed that a liberal transfusion strategy did not significantly reduce the risk of recurrent MI or death at 30 days (relative risk [RR] 1.15, 95% confidence interval [CI] 0.99-1.34), p = 0.07). In a prespecified subgroup analysis, DeFilippis and colleagues then compared 30-day outcomes in T1 (n=1,460) and T2 (n=1,955) MI patients, finding that patients with T1MI randomized to a restrictive versus liberal transfusion strategy had higher rates of the primary outcome of 30-day death or MI (RR 1.32, 95% CI 1.04-1.67; absolute difference 4.3%), while patients with T2MI (RR 1.05, 95% CI 0.85-1.29; absolute difference 0.6%; interaction p=0.16). Furthermore, they noted that a higher risk of death (RR 1.40, 95% CI 1.01-1.95) and cardiac death (RR 1.61, 95% CI 1.04-2.49) were observed in the restrictive strategy for patients with T1MI, while for T2MI, the risk of cardiac death was higher (RR 1.95, 95% CI 1.19-3.21) in the restrictive strategy. “This prespecified subgroup analysis of the MINT trial, while hypothesis-generating, suggests the use of a liberal transfusion strategy may be particularly impactful in type 1 MI patients with anemia,” said DeFilippis, noting that studying patients with both T1MI and T2MI is feasible in multicenter, randomized controlled clinical trials. “Although the results of this analysis do not provide statistical certainty, the results inform clinicians in the treatment of patients with acute MI and anemia,” he added, noting that a restrictive transfusion strategy “may be harmful, particularly in those with T1MI.” Photo Credit: Jason Wermers/CRTonline.org Photo Caption: Andrew P. DeFilippis, MD, MSc, presents findings from a MINT Trial analysis Sunday at ACC.24 in Atlanta.