Objectives: We sought to determine the relationship between red blood cell (RBC) transfusion and clinical outcomes in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI).
Background: The implications of RBC transfusion in patients undergoing primary PCI for AMI have not been evaluated.
Methods: Clinical outcomes of patients from the prospective, randomized CADILLAC (Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications) trial were analyzed by administration of in-hospital RBC transfusion not related to coronary artery bypass surgery.
Results: Of 2,060 randomized patients, 82 (3.98%) received RBC transfusion during the index hospitalization, including 33 (1.60%) with moderate/severe bleeding and 49 (2.38%) without overt major bleeding. Transfusion was independently associated with baseline anemia (odds ratio [95% confidence interval]: 4.44 [2.60 to 7.58], p < 0.0001), older age (1.03 [1.01 to 1.06], p = 0.002), triple-vessel disease (2.54 [1.47 to 4.38], p = 0.0008), and female sex (1.04 [1.02 to 1.06], p = 0.0008). Patients transfused versus not transfused had significantly higher rates of 1-year mortality (23.9% vs. 3.4%), disabling stroke (2.5% vs. 0.5%), reinfarction (7.0% vs. 2.2%), and composite major adverse cardiac events (41.0% vs. 16.6%) (all p values < 0.01). After multivariable adjustment for potential confounders including transfusion propensity, RBC transfusion was independently associated with mortality at 30 days (hazards ratio: 4.71, p = 0.0005) and 1 year (hazards ratio: 3.16, p = 0.0005).
Conclusions: An RBC transfusion after primary PCI in AMI may be harmful, which is consistent with the findings from other studies after PCI in the noninfarct setting. Alternatively, RBC transfusion may be a marker of markedly increased risk. Randomized studies are warranted to determine the optimal threshold for RBC transfusion in patients with AMI undergoing mechanical reperfusion therapy.