Preoperative anemia does not increase the risks of early surgical revascularization after myocardial infarction.

Background: Recent clinical studies suggest preoperative anemia may increase mortality and morbidity after cardiac surgery. Anemic patients are potentially even more vulnerable in the setting of a recent myocardial infarction (MI). The objective of this study was to investigate the impact of preoperative anemia on short-term outcomes after coronary bypass surgery in patients with a recent MI.

Methods: We conducted a retrospective cohort study of 655 patients who underwent an isolated coronary bypass procedure within 21 days of MI, 432 of whom were anemic preoperatively, defined as a hemoglobin less than 13 g/dL for men and less than 12 g/dL for women. The primary outcomes were in-hospital mortality and major adverse events (MAE), which included MI, stroke, and renal failure requiring dialysis.

Results: Before risk adjustment, in-hospital mortality and the incidence of MAE were significantly higher in patients with anemia versus no anemia (mortality, 5.1% versus 1.4%, p = 0.02; MAE, 8.6% versus 3.1%, p = 0.009). After risk adjustment, the association between preoperative anemia and mortality or MAE became insignificant (mortality odds ratio 2.34, 95% confidence interval: 0.56 to 9.87, p = 0.25; MAE odds ratio 1.13, 95% confidence interval: 0.46 to 2.79, p = 0.78). Preoperative hemoglobin, treated as a continuous variable, yielded similar results.

Conclusions: Preoperative anemia does not directly increase risks of surgical revascularization performed within 21 days of MI.