Restrictive vs Liberal Blood Transfusions for Patients With Acute Myocardial Infarction and Anemia by Heart Failure Status: An RCT Subgroup Analysis

BackgroundRed 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).MethodsWe used data from the randomized REALITY trial (https://www.clinicaltrials.gov/study/NCT02648113), comparing restrictive versus liberal transfusion strategies in patients with AMI and anaemia. 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, non-recurrent AMI, stroke, or emergency revascularization prompted by ischaemia) at 30 days.ResultsAmong 658 randomized patients, 311 (47.3%) had HF. HF patients had higher rates of MACE at 30 days and 1 year, and higher rates of non-fatal new-onset HF. There was no interaction between HF and effect of randomized assignment on the primary outcome or non-fatal new-onset HF. A liberal transfusion strategy was associated with increased all-cause death at 30 days and at 1 year in HF patients (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).ConclusionsHF is frequent in AMI patients with anaemia and is associated with higher risk of MACE (including all-cause death) and non-fatal new-onset HF. While 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 due to HF.