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

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 (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. RESULTS:Among 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). CONCLUSIONS:HF 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.