Alterations of serum erythropoietin and thrombopoietin levels in patients undergoing Coronary Artery Bypass Grafting (CABG)

Abstract

The hormones erythropoietin (EPO) and thrombopoietin (TPO) are main regulators of erythro- and thrombopoiesis. Cell loss caused by operative procedures may alter serum levels of the hormones, resulting in well known phenomenons like reactice thrombocytosis. Blood samples from 10 patients (mean age 63 ± 9 years) were obtained before and at day 1, 5 and 10 after coronary artery bypass grafting (CABG). EPO and TPO levels were determined by commercially available ELISA-Kits (R&D Systems, Germany). In addition, platelet count (PC) and hemoglobin concentration (Hb) were determined. Prior to CABG, EPO (13.2 ± 8.2 mU/mL), TPO (189 ± 52 pg/mL), Hb (8.8 ± 1.1 mmol/L) and PC (254 ± 121/nL) were within a normal range. At day 1 after surgery, Hb and PC were significantly decreased to 6.6 ± 0.9 mmol/L and 138 ± 70/nL. In contrast, EPO and TPO were significantly elevated to 32 ± 18 mU/mL and 336 ± 96 pg/mL, respectively, in spite of hemodilution. In particular, TPO elevation was followed by a significant increase in PC (342 ± 144/nL) at day 10 after surgery compared to preoperative values. Appropriate to the decrease in hemoglobin concentration and platelet count, clear alterations of serum erythropoietin and thrombopoietin levels could postoperatively be observed. EPO levels showed an inverse correlation to hemoglobin concentrations, whereas a disturbed thrombopoietin feedback mechanism resulted in the phenomenon of reactive thrombocytosis.