Interpretation:

The MINT trial demonstrated that, in patients with acute MI and comorbid anemia, a liberal transfusion strategy targeting Hgb concentration ≥10 g/dL was not superior to a restrictive target of 7-8 g/dL with respect to all-cause death or nonfatal MI at 30 days. Though not significant, there was a trend toward increased events of both the primary composite endpoint and its components in the restrictive strategy arm. This was also true on prespecified subgroup analysis. Although interaction testing did not reveal a significant difference between type 1 and type 2 MI, the type 1 MI subset demonstrated a signal of increased harm due to all-cause death with a restrictive transfusion strategy. Acute anemia was associated with increased risk of death or recurrent MI (RR 1.25, 95% CI 1.05-1.48), but no response favoring a liberal transfusion strategy was observed compared to patients with chronic anemia.

There have been limited data to guide transfusion thresholds for acute MI complicated by anemia. The REALITY trial (n = 668) previously demonstrated noninferiority of a restrictive transfusion strategy in MI with respect to 30-day major adverse cardiovascular events. However, the study authors noted that the noninferiority margin of 1.25 may include clinically relevant harm. Moreover, the restrictive strategy was no longer noninferior on prespecified analysis at 1 year. Considering these data, the trend toward clinical benefit observed in MINT suggests that a liberal transfusion strategy in MI, particularly type 1 events, may be reasonable to consider without an appreciably increased risk of harm.