Endogenic erythropoietin secretion in patients undergoing off-pump coronary artery bypass grafting

Background: Erythropoietin (EPO) deficiency or inadequate EPO secretion in response to bleeding may result in profound or prolonged anaemia after cardiac surgery. Aim: The aim of the study was to evaluate the changes in EPO secretion in patients undergoing off-pump coronary artery bypass grafting (OPCAB). Methods: Blood samples from 43 patients (mean age 65.1 +/- 7.6 years) were obtained before surgery and on the 1st, 2nd, and 6th day post isolated OPCAB. EPO levels >= 4.3 mIU/mL were considered normal. Results: Thirteen (30%) patients had the preoperative EPO level below normal range even though their preoperative haemoglobin was >= 13 g/dL. In patients with basal EPO deficiency lower peak EPO levels were observed compared to the group with normal basal EPO levels, even though reduction in haemoglobin concentrations was comparable in both groups. Moreover, lower reticulocytosis was noted on day 1 (8.5 +/- 4.0% vs. 11.7 +/- 4.4%; p = 0.04) and a tendency toward lower values was seen on day 2 (9.6 +/- 4.3% vs. 13.0 +/- 5.8%; p = 0.07) among patients with preoperative EPO deficiency. Conclusions: Erythropoietin deficiency is common in patients scheduled for OPCAB, and it results in diminished increase in EPO secretion in response to bleeding. Consequently, in patients with EPO deficiency, reticulocytosis is lower than it could be predicted based on the observation of patients with normal EPO levels and similar blood loss.