Effects of Epoetin alfa on hemostasis in chronic renal failure

Should We Use Preoperative Epoetin-α in the Mildly Anemic Patient Undergoing Simultaneous Total Knee Arthroplasty?

Simultaneous knee arthroplasty is associated with significant blood loss. To prevent transfusion, three preoperative doses of epoetin-α were offered to mildly anemic simultaneous knee arthroplasty patients. A retrospective review, using ICD-9 codes, identified twenty patients from 2007-2009. Epoetin-α increased hemoglobin levels preoperatively (12.6 to 13.9, p<0.01). Twenty patients who did not receive epoetin-α were matched to study patients. Study patients were transfused less (55% vs 95%, p=0.012) and had similar inpatient length of stay. The average blood loss without transfusion was 4.6g/dL. The mildly anemic patient is at high-risk for packed red cell transfusion during simultaneous knee arthroplasty. Three preoperative doses of epoetin-α in the mildly anemic patient decreased total transfusions; however, it did not affect inpatient length of stay.

Impaired thrombolysis: a novel cardiovascular risk factor in end-stage renal disease

AIMS

End-stage renal disease (ESRD) patients have an excess cardiovascular risk, above that predicted by traditional risk factor models. Prothrombotic status may contribute to this increased risk. Global thrombotic status assessment, including measurement of occlusion time (OT) and thrombolytic status, may identify vulnerable patients. Our aim was to assess overall thrombotic status in ESRD and relate this to cardiovascular risk.

METHODS AND RESULTS

Thrombotic and thrombolytic status of ESRD patients (n = 216) on haemodialysis was assessed using the Global Thrombosis Test. This novel, near-patient test measures the time required to form (OT) and time required to lyse (lysis time, LT) an occlusive platelet thrombus. Patients were followed-up for 276 ± 166 days for major adverse cardiovascular events (MACE, composite of cardiovascular death, non-fatal MI, or stroke). Peripheral arterial or arterio-venous fistula thrombosis was a secondary endpoint. Occlusion time was reduced (491 ± 177 vs. 378 ± 96 s, P < 0.001) and endogenous thrombolysis was impaired (LT median 1820 vs.1053 s, P < 0.001) in ESRD compared with normal subjects. LT ≥ 3000 s occurred in 42% of ESRD patients, and none of the controls. Impaired endogenous thrombolysis (LT ≥ 3000 s) was strongly associated MACE (HR = 4.25, 95% CI = 1.58-11.46, P = 0.004), non-fatal MI and stroke (HR = 14.28, 95% CI = 1.86-109.90, P = 0.01), and peripheral thrombosis (HR = 9.08, 95% CI = 2.08-39.75, P = 0.003). No association was found between OT and MACE.

CONCLUSION

Impaired endogenous thrombolysis is a novel risk factor in ESRD, strongly associated with cardiovascular events.

The Use of Epoetin-α in Revision Knee Arthroplasty

Introduction. To evaluate the efficacy of epoetin-α prior to revision total knee arthroplasty, we hypothesized that epoetin-α will reduce blood transfusion. Methods. Eighty-one patients were compared in this retrospective review; twenty-eight patients received our dosing regimen. All patients were mildly anemic. Epoetin-α to control (1 : 2) patient matching occurred so that one of two attending surgeons, gender, BMI, complexity of surgery, ASA score, and age were similar between groups. The clinical triggers for blood transfusion during or after the procedure were determined based on peri- and postoperative hemoglobin levels, ASA score, and/or clinical symptoms consistent with anemia. Blood salvage was not used. Results. Blood transfusion and length of stay were lower in the study group. None of the patients who received epoetin-α underwent transfusion. Hemoglobin increased from 11.97 to 13.8, preoperatively. Hemoglobin at day of surgery and time of discharge were higher. Gender, BMI, ASA score, total and hidden blood losses, calculated blood loss, preop PLT, PT, PTT, and INR were similar between groups. One Epogen patient had an uncomplicated DVT (3.6%). Conclusions. Epoetin-α may have a role in the mildly anemic revision knee patient. It may also decrease patient length of stay allowing for earlier readiness to resume normal activities and/or meet short-term milestones. A randomized study to evaluate the direct and indirect costs of such a treatment methodology in the mildly anemic revision patient may be warranted.

Liver transplant in Jehovah's Witnesses patients

PURPOSE OF REVIEW

The Jehovah's Witness religion is a Christian movement, founded in the USA in the 1870s, with 6 million members worldwide (150,000 in the UK). Members of this faith have strong beliefs based upon passages from the Bible that are interpreted as prohibiting the 'consumption' of blood. Their beliefs prevent them from accepting transfusion of whole blood or its primary components. They also believe that blood that has been removed from the body is 'unclean' and should be disposed of. The use of procedures that involve the removal and storage of their own blood is often unacceptable.

RECENT FINDINGS

Biological hemostats, including collagen and cellulose pads (Kaltostat) and fibrin glues and sealants (Tisseal), aid coagulation and reduce blood loss. Strategies have been described to reduce the number of red cells lost during hemorrhage by the nonlinear reduction in packed cell volume achieved by hemodilution. With the cell-saver technique, shed blood is suctioned from the wound, centrifuged, washed, mixed with an additive/anticoagulant solution and then reinfused as required. Many coagulation factors are available as recombinant products, including factors VIII, IX and VIIa.

SUMMARY

In summary, major surgery can be performed safely in the Jehovah's Witness who refuses blood transfusion by utilizing preoperative and intraoperative techniques that decrease surgical blood loss, decrease oxygen consumption, and increase oxygen delivery. Even if significant intraoperative blood loss occurs, successful postoperative management is possible by utilizing techniques that minimize oxygen consumption and maximize oxygen delivery.

The normal hematocrit cardiac trial revisited

The Normal Hematocrit Cardiac Trial (NHCT) was the first large, randomized study of patients receiving hemodialysis to examine the outcomes of treating anemia to a target hematocrit range of 42 +/- 3% versus maintaining partial correction in a range of 30 +/- 3%. The results of the NHCT and a meta-analysis adding eight subsequent trials of normalization of hematocrit/hemoglobin in chronic kidney disease (CKD) have demonstrated increased thrombovascular events and mortality associated with the higher targets. This article expands and clarifies the results of the NHCT, including data that were edited from the original publication, and highlights findings from more recent studies in the field. Paradoxically, none of the randomized trials has reported an association between higher attained hemoglobin concentration and mortality within randomized groups. Mean platelet count did not increase among the patients in the normal-hematocrit group in the NHCT or in two other large trials, CREATE and CHOIR. Exposure to high doses of erythropoietic stimulating agents and/or intravenous iron could be mediating complications in the CKD anemia-normalization studies, but post-hoc analyses to probe such potential associations have yielded conflicting results and are clearly hindered by the risk of confounding by indication. The mechanisms underlying the deleterious outcomes associated with efforts to correct renal anemia fully remain unproven.

What is so bad about a hemoglobin level of 12 to 13 g/dL for chronic kidney disease patients anyway?

Randomized controlled trials (RCTs) clearly indicate a possible cardiovascular morbidity and mortality risk when deliberately targeting a normal hemoglobin (Hb) concentration of 13 to 15 g/dL. By contrast, observational studies point to greater hospitalization and mortality at Hb levels <11 g/dL. There are no direct data to help us determine where, within this broad range, the optimal Hb lies. In RCTs and observational studies, significant confounding from the interrelationships of anemia and epoetin resistance occurs in patients with a serious illness. Patients with comorbidities such as malnutrition and inflammatory processes are more resistant to epoetin and, invariably, require greater cumulative epoetin doses. The effect of a higher erythropoiesis-stimulating agent (ESA) dose on increasing mortality has been noted repeatedly in post hoc analyses of RCTs. It is therefore too simplistic to solely attribute the outcomes achieved in RCTs to "target Hb." We discuss various mechanisms for potential harm at higher Hb levels as opposed to those that may be obtained from higher epoetin doses. For the individual patient, the therapeutic decision should center on what Hb is most appropriate at a "safe" ESA dose. Consequently, an Hb of 12 to 13 g/dL may be totally appropriate in some patient populations.

Effects of recombinant human erythropoietin on antiplatelet action of aspirin and clopidogrel in healthy subjects: results of a double-blind, placebo-controlled randomized trial

BACKGROUND

Recombinant human erythropoietin (rHuEpo) reduces myocardial injury in experimental ischemia and has been proposed as a cardioprotective agent for potential use in acute coronary syndromes. Its safety profile in clinical acute ischemic settings is uncertain because rHuEpo has been reported to increase platelet reactivity and the risk of thromboembolism in some disease populations. Whether prothrombotic effects of rHuEpo mitigate the effects of antiplatelet agents used in acute coronary syndrome patients is unknown.

METHODS

Recombinant human erythropoietin 100, 200, 400 U/kg, or placebo was given intravenously once daily for 3 consecutive days in a double-blind randomized trial in 96 healthy subjects. A single oral dose of aspirin 325 mg or clopidogrel 300 mg was given immediately after the last dose of study drug. Bleeding time and in vitro high shear stress platelet function assays (PFA)-100 were determined before; 5 hours; and 1, 5, and 7 days after aspirin or clopidogrel.

RESULTS

Recombinant human erythropoietin at doses of 100 and 200 U/kg did not alter bleeding time or PFA-100 closure times at any time point when compared with placebo. Recombinant human erythropoietin at a dose of 400 U/kg significantly blunted the post-aspirin increase in bleeding time when compared with placebo (P = .03) but did not alter post-clopidogrel bleeding times nor PFA closure times. The 400-U/kg dose did not change hematocrit but did significantly increase the platelet count at 5 days after study drug administration when compared with placebo (P = .014).

CONCLUSION

Short-term rHuEpo at doses up to 200 U/kg did not mitigate the effects of administration of aspirin or clopidogrel on either in vivo or in vitro measures of platelet function in healthy subjects. The 400-U/kg dose attenuated the effects of aspirin on bleeding time and increased the platelet count. Studies of the effects of rHuEpo on platelet function in patients with coronary artery disease are warranted to further characterize dose/safety profile.

Nonhematologic complications of erythropoietin therapy

Exogenous recombinant human erythropoietin (rHuEPO) is a beneficial therapeutic agent for correction of anemia in both chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients. Transfusion requirements in ESRD patients are reduced significantly and anemia management is much improved. Despite widespread use and near-universal exposure of ESRD patients to the drug, rHuEPO remains an effective and safe product. However, a number of nonhematologic complications are described with rHuEPO therapy. Most notable is hypertension, whereas the connection between seizure and enhanced thrombosis is less clear. A possible complication recently described is exacerbation of proliferative diabetic retinopathy. Finally, other less common adverse effects, although rare in most patients, should be recognized as such by physicians who prescribe rHuEPO.

Platelet surface receptor activation in patients with chronic renal failure on hemodialysis, peritoneal dialysis and those with successful kidney transplantation

Hemostatic disorders associated with chronic renal failure (CRF) include hemorrhagic and/or thrombotic manifestations, which were ascribed, in part, to uremic platelet dysfunction including abnormalities of expression of platelet glycoprotein receptors. There is, however, still no general agreement on the exact characterization of these platelet abnormalities. This study aims at characterizing the platelet glycoprotein abnormalities associated with CRF, by recording the effect of the three renal replacement therapies, hemodialysis (HD), chronic ambulatory peritoneal dialysis (CAPD), and renal transplantation, on these receptors. The study, which was mainly cross-sectional, included two groups: (i) Patient groups (n = 50): HD patients (n = 20), CAPD patients (n = 10) and successful renal transplant patients (n = 20); (ii) Healthy Controls (n = 34): 23 were men and 11 were women who were age- and sex-matched with the patients. Flow cytometric quantitation of CD41, CD42a, CD42b and CD61 was carried out using a Becton-Dickinson FACScan. The expression of CD41 levels showed a highly significant increase in HD and CAPD patients when compared with the normal control levels. However, levels in transplant patients were comparable to the normal control levels. On the other hand, the expression of CD42a, CD42b, and CD61 showed no significant change in HD and CAPD patients when compared with normal control levels, but there was a significant decrease in transplant patients when compared to the normal control levels. In conclusion, there was evidence of increased expression of one glycoprotein receptor (GpIIb-IIIa) pre-dialysis whether HD or CAPD. In transplant patients, no evidence of platelet activation could be demonstrated.

Erythropoietin Just Before Reperfusion Reduces Both Lethal Arrhythmias and Infarct Size via the Phosphatidylinositol-3 Kinase-Dependent Pathway in Canine Hearts

Although recent studies suggest that erythropoietin (EPO) may reduce multiple features of the myocardial ischemia/reperfusion injury, the cellular mechanisms and the clinical implications of EPO-induced cardioprotection are still unclear. Thus, in this study, we clarified dose-dependent effects of EPO administered just before reperfusion on infarct size and the incidence of ventricular fibrillation and evaluated the involvement of the phosphatidylinositol-3 (PI3) kinase in the in vivo canine model. The canine left anterior descending coronary artery was occluded for 90 min followed by 6 h of reperfusion. A single intravenous administration of EPO just before reperfusion significantly reduced infarct size (high dose (1,000 IU/kg): 7.7 +/- 1.6%, low dose (100 IU/kg): 22.1 +/- 2.4%, control: 40.0 +/- 3.6%) in a dose-dependent manner. Furthermore, the high, but not low, dose of EPO administered as a single injection significantly reduced the incidence of ventricular fibrillation during reperfusion (high dose: 0%, low dose: 40.0%, control: 50.0%). An intracoronary administration of a PI3 kinase inhibitor, wortmannin, blunted the infarct size-limiting and anti-arrhythmic effects of EPO. Low and high doses of EPO equally induced Akt phosphorylation and decreased the equivalent number of TUNEL-positive cells in the ischemic myocardium of dogs. These effects of EPO were abolished by the treatment with wortmannin. In conclusion, EPO administered just before reperfusion reduced infarct size and the incidence of ventricular fibrillation via the PI3 kinase-dependent pathway in canine hearts. EPO administration can be a realistic strategy for the treatment of acute myocardial infarction.

Anemia as a risk factor and therapeutic target in heart failure

Anemia has recently been recognized as an important comorbid condition and potentially novel therapeutic target in patients with heart failure (HF). Anemia is common in HF patients, with a prevalence ranging from 4% to 55% depending on the population studied. Multiple potential mechanisms of interaction exist between anemia and the clinical syndrome of HF, including hemodilution, inflammatory activation, renal insufficiency, and malnutrition. A growing body of literature from observational databases and clinical trials suggests that anemia is an independent risk factor for adverse outcomes in patients with HF. Although preliminary data suggest that treatment of anemia may result in significant symptomatic improvement in HF, aggressive treatment of anemia may also be associated with increased risk of hypertension or thrombosis. Multiple ongoing studies will provide definitive data on the balance of risks and benefits of anemia treatment in chronic HF.

Endothelial dysfunction marker von Willebrand factor antigen in haemodialysis patients: associations with pre-dialysis blood pressure and the acute phase response

BACKGROUND

Increased plasma soluble von Willebrand factor antigen (vWF : Ag) level, a marker of vascular endothelial cell dysfunction, is a strong predictor of atherosclerotic cardiovascular disease (CVD) in the general population. We studied cross-sectional associations between vWF : Ag level, prevalence of CVD, and related factors including pre-dialysis arterial blood pressure (BP) and some markers of inflammation in maintenance haemodialysis (HD) patients. Methods and results. Plasma vWF : Ag level measured by an enzyme-linked immunosorbent assay (ELISA) was higher in 110 HD patients than in 20 controls. On bivariate regression analysis, vWF : Ag level was directly associated with the presence of CVD, age, fibrinogen and the use of enoxaparin (vs unfractionated heparin) during HD procedures, and inversely with albumin and pre-dialysis BP. The patients with prevalent CVD were older, had higher vWF : Ag, white blood cell and platelet counts, fibrinogen and triglycerides, lower albumin levels, and were less frequently on combination antihypertensive therapy. Multivariable analyses identified low pre-dialysis BP, hypoalbuminaemia and hyperfibrinogenaemia (in descending order of significance) as independent predictors of high vWF : Ag level. There were no associations between vWF : Ag levels and gender, ABO blood type, smoking, body mass index, renal failure cause, duration of HD therapy, K(t)/V, normalized protein catabolic rate, dialysate buffers, dialysers, viral hepatitis, erythropoietin treatment, specific antihypertensive drugs, haemoglobin, white blood cell and platelet counts, liver enzymes, phosphorous, total cholesterol, and triglycerides.

CONCLUSION

Elevated plasma levels of endothelial dysfunction marker vWF : Ag in maintenance HD patients are associated with established cardiovascular mortality risk factors such as low pre-dialysis blood pressure and the activated acute phase response.

The pathological consequences of anaemia

Many patients with chronic diseases such as chronic renal failure, chronic inflammatory bowel disease and rheumatoid arthritis are anaemic. Recently congestive heart failure (CHF) has also been found to be associated with anaemia. In all these diseases this anaemia or chronic disease is at least partially due to excessive production of cytokines and leukotrines that interfere both with the effect of erythropoietin (EPO) at the bone marrow and the release of stored iron in the reticuloendothelial system. Treating this anaemia with subcutaneous EPO and IV iron improves the weakness, fatigue, cachexia, nutritional state, mood, cognitive function and quality of life. In the case of CHF it also improves cardiac function and patient functional class, prevents deterioration of renal function and markedly reduces hospitalization. Very few agents in medicine improve so many aspects of the patient so well and so quickly. Unfortunately (for the suffering patient) this anaemia is often ignored and goes untreated.

Normalization of haemoglobin concentration with recombinant erythropoietin has minimal effect on blood haemostasis

BACKGROUND

Elevation of haemoglobin (Hb) with recombinant erythropoietin (rHuEpo) in patients with chronic renal failure has raised concern of increased risk of thromboembolic diseases. In this study, a substudy of the Scandinavian multicentre trial, we examined the influence on haemostatic parameters of normalization of Hb levels from subnormal levels in patients with chronic renal failure.

METHODS

Twenty-six patients, 17 males (before study start Hb 113+/-6 g/l) and nine females (Hb 111+/-8 g/l), with end-stage renal disease were included. Both dialysis and predialysis patients were included. After 3 months of rHuEpo therapy Hb levels reached 136+/-14 g/l for males and 128+/-13 g/l for females, and after 1 year 142+/-11 g/l and 126+/-14 g/l respectively. The increase in Hb was significant both at 3 months and 1 year, compared to baseline. At baseline, after 3 months and 1 year haemostatic and prothrombotic parameters were measured, including prothrombin complex test, activated partial thromboplastin time, platelet aggregation and retention, von Willebrand factor antigen, antithrombin, protein C, total and free protein S, activated protein C resistance, FV-Leiden mutation, D-dimers, plasminogen activator inhibitor-1 and prothrombin fragments 1+2 (PF 1+2).

RESULTS

The only statistically significant change was a transient decrease in total levels of protein S at 3 months from 131 to 120% (P=0.0093). The free and active form of protein S showed no significant change. After 1 year the difference was not seen.

CONCLUSIONS

Apart from a transient and clinically insignificant decrease in total protein S, we found no prothrombotic changes after normalization of Hb from subnormal levels. Our findings indicate that rHuEpo treatment may aim at normalizing Hb levels without significant effects on haemostatic parameters in patients with chronic renal failure compared to patients with subnormal Hb levels.

The use of pretransplant erythropoietin to normalize hemoglobin levels has no deleterious effects on renal transplantation outcome

BACKGROUND

The aim of this study was to establish the outcome of renal transplantation in patients given pretransplant erythropoietin (EPO) treatment targeted at reaching a normal hemoglobin concentration (Hb), compared to those given EPO-treatment aimed at maintaining subnormal Hb.

METHODS

A total of 416 patients from Scandinavian countries and with renal anaemia were enrolled to examine the effects of increasing Hb from a subnormal level (90-120 g/liter) to a normal level (135-160 g/liter) by EPO treatment. Half of the patients were randomized to have their Hb increased, with the other half randomized to maintain a subnormal Hb. Thirty-two patients from the normal Hb group and 24 patients from the subnormal group received a renal graft during the study period. The outcomes of these transplantations were examined prospectively for 6 months.

RESULTS

Preoperative Hb levels were 143+/-17 and 121+/-14 g/liter in the two groups, respectively (P<0.0001). The Hb remained higher in the normal Hb group during the first 2 weeks after transplantation. The percentage of patients requiring postoperative blood transfusions in the normal Hb group was 16%, compared with 50% in the subnormal group (P<0.01). No statistically significant difference in the proportion of functioning grafts or in the serum creatinine levels could be detected. No correlation between EPO treatment and creatinine levels after transplantation was found. The frequency of adverse events was similar in the two groups.

CONCLUSIONS

EPO treatment aimed at reaching a normal Hb in renal transplant recipients reduces the postoperative requirement for blood transfusions and has no deleterious effects on kidney graft function.

Liver transplantation in a Jehovah's Witness with ankylosing spondylitis

PURPOSE

Orthotopic liver transplantation is typically associated with large volume blood loss. Technological and pharmacological advances permit liver transplantation in patients who formerly were not candidates for this surgery because of strict limitations on blood product administration. We describe a liver transplant in a Jehovah's Witness with ankylosing spondylitis.

CLINICAL FEATURE

A 49-yr-old Jehovah's Witness with ankylosing spondylitis and end stage liver disease secondary to sclerosing cholangitis underwent orthotopic liver transplantation. Recombinant human erythropoietin (4,000 IU sc every two days for four weeks, then 4,000 IU sc every week) established a normal hemoglobin concentration preoperatively (> 140 g x L(-1) compared with 120 g x L(-1) baseline). Intraoperatively, strategies for reducing risk of blood product transfusion included avoidance of hypothermia (T>35 degrees C), minimal blood sampling (four 1 ml samples), normovolemic hemodilution (two units), administration of Aprotinin (2 million units bolus dose followed by infusion of 500,000 u x hr(-1)), and return of blood (1,500 ml) scavenged from the operative field. Estimated blood loss was 2,200 mi. The preoperative and postoperative hemoglobin concentration was 147 g x L(-1) (hematocrit 0.45) and 123 g x L(-1) (hematocrit 0.37), respectively. No blood products were required and he was discharged three weeks postoperatively without complication.

CONCLUSION

Technological and pharmacological advances allow patients to undergo surgery traditionally associated with large volume blood loss with reduced risk of blood product administration.

Management of bleeding with uremia and liver disease

Bleeding can complicate the clinical course of both liver disease and uremia. The pathogenesis of bleeding in both syndromes is complex. A variety of options are available for treatment of uremic bleeding including desmopressin, erythropoietin, and estrogens. Bleeding complications of liver disease reflect the importance of this organ for the production of both coagulation factors and thrombopoietin. Careful assessment of both the patient's clinical situation and laboratory findings is important for tailoring therapy of the bleeding patient.

Adenosine 5'-diphosphate-induced platelet aggregation in uremia shows resistance to inhibition by the novel nitric oxide donor GEA 3175 but not by S-nitroso-N-acetylpenicillamine

Both bleeding and thrombosis are complications of uremia in patients on regular hemodialysis. An excessive endogenous formation of the vasodilator and platelet inhibitor nitric oxide (NO) has been proposed to contribute to the bleeding defect. Since exposure to pharmacological donors of NO, nitrovasodilators, can cause tolerance to NO, we investigated whether platelets from uremic patients on regular hemodialysis are influenced differently by NO donors than platelets from healthy subjects. A frequently used S-nitrosothiol, S-nitroso-N-acetylpenicillamine (SNAP), was compared to a recently synthezised mesoionic oxatriazole derivate, GEA 3175, regarding its capacity to inhibit adenosine 5'-diphosphate (ADP)-induced platelet aggregation in vitro. The final products of NO production, nitrite + nitrate, were found to be significantly increased in uremic patients. The capacity to inhibit platelet aggregation by SNAP was only slightly different between the groups. However, GEA 3175 showed a significantly marked and reduced capacity to inhibit aggregation of uremic platelets compared to controls. Interactions of erythropoietin (EPO) with NO have earlier been reported. Addition of EPO to platelets from healthy donors in vitro did not significantly influence the NO donor capacity to inhibit platelet aggregation, but showed a tendency to enhance the effect of SNAP while the effect of GEA 3175 was inhibited. These results suggest compound-specific resistance to NO donors in uremic platelet activation.