BACKGROUND: Red blood cell transfusion can cause fluid overload. We evaluated the interaction between heart failure (HF) at baseline and transfusion strategy on outcomes in acute myocardial infarction (AMI). METHODS: We used data from the randomized REALITY trial. HF was defined as history of HF or Killip class > 1 at randomization. Primary outcome was major adverse cardiovascular events (MACE): composite of all-cause death, nonrecurrent AMI, stroke, or emergency revascularization prompted by ischemia at 30 days. RESULTS: Among 658 randomized patients, 311 (47.3%) had HF. Patients with HF had higher rates of MACE at 30 days and 1 year and higher rates of nonfatal new-onset HF. There was no interaction between HF and effect of randomized assignment on the primary outcome or nonfatal new-onset HF. A liberal transfusion strategy was associated with increased all-cause death at 30 days and at 1 year in patients with HF (Pinteraction = 0.009 and P = 0.049, respectively). The main numerical difference in cause of death between restrictive and liberal strategies was death by HF at 30 days (4 vs 11). CONCLUSIONS: HF is frequent in patients with AMI and anemia and is associated with higher risk of MACE (including all-cause death) and nonfatal new-onset HF. Although there was no interaction of HF with effect of transfusion strategy on MACE, a liberal transfusion strategy was associated with higher all-cause death that appears driven by a higher risk of early death caused by HF. CLINICAL TRIAL REGISTRATION: NCT02648113.
