Evaluation of erythropoietic activity on the basis of the red cell and reticulocyte distribution widths during epoetin beta therapy in patients undergoing cardiac surgery

The changes in the red cell and reticulocyte distribution widths during preoperative treatment with recombinant human erythropoietin (rhEPO) were evaluated in a double-blind, placebo-controlled trial in cardiac surgery patients. The increases in the reticulocyte count, in the hemoglobin and in all distribution widths are the expression of the marked preoperative stimulation of erythropoiesis in the patients treated with rhEPO. Only placebo patients with a hemoglobin < or = 7.5 mmol/l or a transferrin > 4.0 g/l at baseline showed an increase in the red cell distribution width or in the reticulocyte hemoglobin distribution width on oral iron therapy alone. While the reticulocyte count and the distribution widths of red cells in the rhEPO patients decreased postoperatively, only the increases in the distribution widths of reticulocytes after the second postoperative day indicate that stimulation oferythropoiesis had taken place. In patients with a low hemoglobin or a high transferrin the rhEPO therapy should be preceded by iron therapy in order to raise the hemoglobin level and reduce the cost of treatment.

The estimation of efficacy of oral iron supplementation during treatment with epoetin beta (recombinant human erythropoietin) in patients undergoing cardiac surgery

We estimated the efficacy of oral iron therapy during treatment with rhEPO in patients undergoing cardiac surgery who were contraindicated for autologous blood donation. Seventy-six patients were enrolled in this double-blind, placebo-controlled trial and assigned to the 2 treatment groups (5x500 U/kg body weight rhEPO or placebo intravenously over 14 d before surgery). During the treatment period all patients received 300 mg Fe2+ (iron glycine sulfate) orally per day. rhEPO therapy produced significant increases in hemoglobin concentration (Hb), reticulocyte count, hematocrit (Hct) and the hypochromic red blood cells (HRBC), and a decrease in transferrin saturation (41%) compared to the placebo group before surgery. However, the preoperative increase in HRBC was independent of the baseline ferritin and even correlated positively with the preoperative increase in Hct (r=0.47, p<0.01). In rhEPO patients there were inverse correlations between baseline serum iron and the preoperative increases in Hb (r=-0.39, p<0.05), Hct (r=-0.50, p<0.01) and HRBC (r=-0.53, p<0.001). With this treatment regimen the HRBC appear to reflect the degree of erythropoietic stimulation rather than functional iron deficiency. The preoperative increases in reticulocytes, HRBC and Hb/Hct in patients with ferritin <100 mg/l or transferrin saturation <16% showed no significant difference compared to their complementary groups. The preoperative decrease in storage iron and the inverse correlation between the baseline ferritin and the preoperative change in ferritin (r=-0.94, p<0.0001) in the rhEPO group indicate that the iron requirement for hemoglobin synthesis is probably covered by the breakdown of stored iron and an increase in the rate of absorption of orally administered Fe2+. Intravenous rhEPO treatment with 5x500 U/kg body weight in combination with 300 mg oral Fe2+/d given over 14 d before surgery is a suitable regimen to increase Hb by about 1.61 g/dl and Hct by 0.06.

The safety of treatment with recombinant human erythropoietin in clinical use: a review of controlled studies

Recombinant human erythropoietin (rhEPO) has now been approved for the treatment of renal anemia, anemia of prematurity, cancer-associated anemia, AIDS-associated anemia and as concomitant treatment for patients with or without autologous blood donation awaiting elective surgery. The purpose of this review is to provide an overview, based on the results of controlled studies, of the anticipated safety profile of rhEPO in various indications and to assess whether treatment with rhEPO influences the incidences of certain adverse events in these indications. The anticipated adverse events differ from indication to indication and generally reflect the corresponding underlying illness. With most indications, no relevant differences in the incidences of adverse events are observed between rhEPO and placebo-control/patients. Only in the rhEPO therapy of renal anemia is an increased incidence of hypertensive events observed in the rhEPO groups, a finding that is not reproduced with the other indications. The controlled studies forming the basis of this review provide no evidence of a relevant increase in the risk of thromboembolic events during rhEPO therapy. Overall, it may be stated that rhEPO treatment, where strictly indicated, is a safe form of therapy. As with any other treatment, the risk of side effects in certain predisposed patients must also be weighed against the desired clinical benefits.

Kinetics of reticulocyte maturity fractions and indices and iron status during therapy with epoetin beta (recombinant human erythropoietin) in cardiac surgery patients

We evaluated the changes in reticulocyte maturity fractions and indices, as measured by flow cytometry, during preoperative treatment with recombinant human erythropoietin (epoetin beta) in cardiac surgery patients. A total of 72 patients was enrolled in this double-blind, randomized, placebo-controlled clinical trial and assigned to the two treatment groups (5 x 500 U/kg bodyweight epoetin beta or placebo intravenously over 14 days preoperatively). Therapy with epoetin beta produced continuous increases in hematocrit/hemoglobin, in the most mature fraction of reticulocytes (LR), and in reticulocyte count. In the first treatment week there were parallel increases in the fraction of most immature reticulocytes (HR) and in the reticulocyte mean cell volume. During the second week of treatment the reticulocyte mean cell hemoglobin content (CHr) decreased, but CHr was independent of all iron parameters, affecting neither the reticulocyte fractions nor the hematocrit/hemoglobin increase. The total preoperative rise in hematocrit correlated with the rises in LR fraction (P = 0.0270) and reticulocyte count (P = 0.0486) during the first week of treatment. Whereas in the epoetin beta patients the preoperative change in HR fraction showed negative correlations with transferrin saturation at baseline (P = 0.0058) and with the preoperative change in iron (P = 0.0113), the preoperative change in the LR fraction correlated positively with transferrin at baseline (P = 0.0115). Postoperatively, the reticulocyte parameters revealed that the onset of increased stimulation of erythropoiesis did not occur in the placebo patients until the second postoperative day, whereas erythropoietic activity in the epoetin beta patients was much higher during the postoperative period as well, as a result of the preoperative stimulation of erythropoiesis. The reticulocyte parameters measured by flow cytometry permitted an objective analysis of erythropoietic activity during treatment with epoetin beta and in all patients postoperatively. Further studies in various types of epoetin beta therapy are needed in order to clarify the value of these reticulocyte parameters for identification of iron deficiency and optimization of epoetin beta treatment regimen.

The effect of preoperative recombinant human erythropoietin therapy on platelets and hemostasis in patients undergoing cardiac surgery

In a double-blind, randomized, placebo-controlled trial we evaluated the effects of the administration of recombinant human erythropoietin (5 x 500 U epoetin beta/kg body weight intravenously over a 14-day period before surgery) in patients undergoing cardiac surgery and in whom autologous blood donation was contraindicated on platelet count, platelet distribution width, mean platelet volume (MPV), and certain hemostaseologic parameters. All patients received 3 x 70 IU heparin/kg per day s.c. from 2 days before operation. No thromboembolic events were associated with epoetin beta therapy during the study period. The thrombocytic parameters showed no significant changes in the placebo group before surgery, and the preoperative hematocrit increase in the epoetin beta group was accompanied with an MPV drop (in contrast to the known MPV rise in recombinant human erythropoietin-treated patients with uremia) by a mean of 0.85 fl and a platelet distribution width rise by 3.3% without a significant change in platelet count. In the epoetin beta group the coagulation time (K) of thromboelastogram (TEG) showed an increase from 4.8 to 5.4 minutes by the seventh study day and after the initiation of heparin therapy a further increase to 7.5 minutes. The higher preoperative K increase in the epoetin beta group may partly be a result of the MPV reduction, because smaller platelets are less reactive, a fact underlined by the negative correlation between the preoperative changes of MPV and reaction time of TEG (r = -0.58, p = 0.0148). In contrast, in the placebo group the K of TEG increased only after the start of heparin therapy (from 5.1 to 6.4 minutes). The significant drop in MPV in the epoetin beta group and the higher increase in K of TEG and the other investigated hemostatic parameters do not suggest any increased thromboembolic risk during the preoperative epoetin beta therapy. Therefore this treatment seems to be a safe way for increasing mean hematocrit by approximately 0.06 within the normal range and reducing the homologous blood requirement in patients undergoing elective cardiac surgery.

Avoidance of allogeneic blood transfusions by treatment with epoetin beta (recombinant human erythropoietin) in patients undergoing open-heart surgery

In a double-blind, randomized, placebo-controlled trial, we evaluated the ability of epoetin beta (recombinant human erythropoietin) to avoid allogeneic blood transfusions (ABT) and the associated risks in patients undergoing primary elective open-heart surgery and in whom autologous blood donation (ABD) was contraindicated. Seventy-six patients overall were enrolled onto the trial and were randomly assigned to the two treatment groups, 5 x 500 U/kg body weight (BW) epoetin beta or placebo intravenously over 14 days preoperatively. All patients received 300 mg Fe2+ orally per day during the treatment period. Preoperatively, the mean hemoglobin increase was 1.50 g/dL greater in epoetin beta patients than in placebo patients (95% confidence interval, 1.10 to 1.90 g/dL), allowing a rapid return to the baseline value by the seventh postoperative day in most epoetin beta patients. The mean volume of blood collected by intraoperative isovolemic hemodilution was 562 mL (red blood cell mass, 274 mL) in the epoetin beta group and 218 mL (red blood cell mass, 94 mL) in the placebo group, respectively. Only four patients (11%) in the epoetin beta group received an ABT, compared with 19 (53%) in the placebo group (P = .0003). Epoetin beta was most useful in patients with a perioperative blood loss greater than 750 mL, in those with a baseline hematocrit value less than 0.42, and in those aged > or = 60 years. The iron supplementation proved adequate despite the fact that a significant decrease in ferritin (median, 48.1%) and transferrin saturation (median, 40.5%) was observed in epoetin beta patients preoperatively. No influence of epoetin beta therapy on blood pressure, laboratory safety variables, or the frequency of specific adverse events was observed. Intravenous epoetin beta treatment of 5 x 500 U/kg BW in combination with 300 mg Fe2+ orally per day administered over 14 days preoperatively is an adequate therapy for increasing mean hemoglobin levels by approximately 1.50 g/dL and reducing the allogeneic blood requirement in patients undergoing elective open-heart surgery and in whom ABD is contraindicated.

Evaluation of oxygen availability with oxygen status algorithm in patients undergoing open heart surgery treated with epoetin beta

We evaluated in a double-blind randomized study the effect of epoetin beta (recombinant human erythropoietin) therapy on oxygen status in patients undergoing cardiac surgery who were contraindicated for autologous blood donation. All 76 patients enrolled in this study were randomized to the two treatment groups (5 x 500 U epoetin beta or placebo/kg body weight intravenously over a 14-day period before surgery) and received 300 mg Fe2+ per day orally before surgery. Before and after surgery the lactate level and the following parameters according to the oxygen status algorithm by Siggaard-Andersen were evaluated: arterial oxygen tension (PaO2), effective hemoglobin concentration (ceHb), arterial oxygen saturation (SaO2), oxygen half saturation tension (p50), red cell 2.3 diphosphoglycerate (2.3 DPG), arterial total oxygen concentration (ctO2), concentration of extractable oxygen (cx), and oxygen compensation factor (Qx). Therapy with epoetin beta led to increases in ceHb, PaO2, ctO2, and cx and to a decrease in Qx before surgery (p < 0.05 for PaO2, p < 0.0001 for the other parameters vs placebo). The cx in patients who received epoetin beta rose by approximately 20%, thus indicating a considerable improvement in O2 delivery. In patients receiving placebo the hemoximetric parameters remained outside the normal limits at all times after surgery, but in the epoetin beta group PaO2, ctO2, cx, and Qx returned almost to their baseline values by the second or fifth postoperative day, even though the frequency of transfusions was significantly higher in the placebo group. Whereas p50 and 2.3 DPG fell in the placebo group after surgery, these two parameters were significantly higher in the epoetin beta group and led to a further increase in cx (from 24% to 38%) versus the placebo group as a result of the right shift in the hemoglobin O2-binding curve. The postoperative incidence and severity of lactic acidosis were higher in the placebo group. Preoperative epoetin beta therapy is a safe way of providing increased extractable O2 (by 24% to 38%) and decreasing the risk of lactic acidosis after surgery. This therapy has a more favorable effect on the O2 binding curve than the transfusion of erythrocyte concentrate and enhances the effect of epoetin beta therapy on the postoperative oxygen status.