[Preoperative anemia in coronary surgery: a risk factor?]

Preoperative anemia as a risk factor of adverse outcomes after coronary surgery has not been well-established. This study has aimed to analyze the association between preoperative anemia and postoperative adverse events and in-hospital mortality in the patients undergoing isolated coronary artery bypass graft surgery in the Son Dureta hospital.

All the patients undergoing isolated coronary artery bypass graft surgery with extracorporeal circulation from November 2002 to June 2007 were included. Preoperative anemia was defined as hemoglobin (Hb)<13g/dL in men and Hb<12g/dL in women. The association between postoperative cardiac and noncardiac adverse events and the presence or absence of preoperative anemia and concomitant surgical risk, assessed by logistic EuroScore, were analyzed.

A total of 623 patients were included. The rate of preoperative anemia was 34.5%. Patients with Euroscore > or =4 had higher incidence of preoperative anemia than patients with Euroscore<4 (41% vs. 27%; p=0.0001). There were no statistically significant differences in the rate of postoperative adverse events related to the presence or absence of preoperative anemia. Median ICU and hospital length of stay were longer in patients with preoperative anemia than in patients without preoperative anemia (ICU: 3.2+/-2.5 days vs. 3.7+/-2.8, p=0.004; in-hospital: 17.5+/-11.3 days vs. 14.7+/-10.2, p=0.001). Hospital mortality rate was 0.8% (95% CI 0.3-1.9). There were no differences in the mortality rate of the patients with and without preoperative anemia (0.9% vs 0.7%, p=0.8).

In this study, preoperative anemia in patients undergoing coronary artery bypass graft surgery was not associated with increased hospital morbidity-mortality. However, ICU and hospital length of stay were longer in patients with preoperative anemia. The limitation of the sample size prevents us from confirming whether preoperative anemia is a risk factor after coronary surgery or not.