Probability of thrombosis of vascular access among hemodialysis patients treated with recombinant human erythropoietin

Pulmonary embolism in chronic kidney disease and end-stage renal disease hospitalizations: Trends, outcomes, and predictors of mortality in the United States

Background:

It is well-known that patients with chronic kidney disease and end-stage renal disease are at increased risk of pulmonary embolism than patients with normal kidney function. However, the data on trends, outcomes, and predictors of mortality in pulmonary embolism patients with chronic kidney disease and end-stage renal disease in the United States are limited.

Methods:

We queried the National Inpatient Sample database from 2010 to 2014. International Classification of Diseases-Ninth Revision-Clinical Modification codes were used to identify patients with normal kidney function, chronic kidney disease, and end-stage renal disease. The frequency of pulmonary embolism, complications, in-hospital mortality, and length of stay were calculated for each cohort. Multivariable logistic regression models were constructed to determine the predictors of mortality.

Results:

In the study population (2010–2014), there were 766,176 pulmonary embolism hospitalizations with normal kidney function, 79,824 with chronic kidney disease, and 9147 with end-stage renal disease. Among the study cohorts, the mortality rate was 2.7% in normal kidney function, 4.5% in chronic kidney disease, and 6.8% in end-stage renal disease hospitalizations. Median length of stay was highest in the end-stage renal disease cohort and lowest in the normal kidney function cohort. After adjusting for confounders, pulmonary embolism patients with chronic kidney disease died 1.15 times more often than those with normal kidney function and pulmonary embolism patients with end-stage renal disease died 4.2 times more often than those with normal kidney function.

Conclusion:

The mortality rate and length of stay in pulmonary embolism patients with chronic kidney disease and end-stage renal disease were significantly higher than those in pulmonary embolism patients with normal kidney function. Also, pulmonary embolism patients with chronic kidney disease and end-stage renal disease were at higher risk of in-hospital mortality than those with normal kidney function. There was statistically significant higher risk of mortality in elderly and Black patients with pulmonary embolism and concurrent chronic kidney disease or end-stage renal disease.

Serum LDL Levels are a Major Prognostic Factor for Arteriovenous Fistula Thrombosis (AVFT) in Hemodialysis Patients

Introduction

Arteriovenous fistula thrombosis (AVFT) is still a common cause of morbidity in patients undergoing regular hemodialysis (HD). Many factors have been found to induce AVFT. Some of those factors are local and others are systemic ones. In this study, we evaluated some local and systemic factors simultaneously, to predict the most potent risk factor for AVFT in HD patients.

Patients and methods

One hundred and eighteen patients aged 20–80 yrs with end-stage renal disease (ESRD) were evaluated prospectively for a period of 14 months. First, anticardiolipin antibodies (ACLA), TG, cholesterol, low density lipoprotein (LDL) and high density lipoprotein (HDL) were analyzed by conventional methods. Other basic data were accessed from patients' medical records. All fistulas were evaluated clinically as patent at the start of this study. Patients were followed-up for any evidence of AVFT within 14 months. Finally, all factors (diabetes, hypertension, presence of ACLA, ultrafiltration ≥3 L, age, gender, weight, hypotension during dialysis, fistula site, epoetin alpha usage, TG, HDL, LDL and total cholesterol) were analyzed in a stepwise regression analysis.

Results

Eighteen episodes of AVFT documented with Doppler sonography occurred in 17 patients (15.3%). Regression analysis showed only LDL values were the AVFT predictor in our patients (p=0.002, β-coefficient=0.3). Kaplan-Meier analysis showed a significantly lower AVF patency time in patients with LDL >130 mg/dl than those with LDL <130 mg/dl (log rank=0.0014).

Discussion

LDL value is a major prognostic factor for AVFT in HD patients and lowering it to <130 mg/dl could improve fistula patency.

Pulmonary embolism in patients with CKD and ESRD

BACKGROUND AND OBJECTIVES

CKD and ESRD are growing burdens. It is unclear whether these conditions affect pulmonary embolism (PE) risk, given that they affect both procoagulant and anticoagulant factors. This study examined the frequency and associated outcomes of PE in CKD and ESRD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Healthcare Cost and Utilization Project's Nationwide Inpatient Sample was used to estimate the frequency and outcomes of PE in adults with CKD and ESRD. Hospitalizations for the principal diagnosis of PE and presence of CKD or ESRD were identified using International Classification of Diseases, Ninth Revision codes. Data from the annual US Census and US Renal Data System reports were used to calculate the number of adults with CKD, ESRD, and normal kidney function (NKF) as well as the annual incidence of PE in each group. Logistic regression modeling was used to compare in-hospital mortality among persons admitted for PE who had ESRD or CKD to those without these conditions.

RESULTS

The annual frequency of PE was 527 per 100,000, 204 per 100,000, and 66 per 100,000 persons with ESRD, CKD, and NKF, respectively. In-hospital mortality was higher for persons with ESRD and CKD (P<0.001) compared with persons with NKF. Median length of stay was longer by 1 day in CKD and 2 days in ESRD than among those with NKF.

CONCLUSIONS

Persons with CKD and ESRD are more likely to have PE than persons with NKF. Once they have PE, they are more likely to die in the hospital.

Pharmacological treatment of chronic systolic heart failure: are we scraping the bottom of the barrel?

Heart failure is a major health problem and its prevalence is growing, primarily as a consequence of the aging of the population. Recently, we have witnessed significant progress in reducing the mortality associated with chronic heart failure due to the introduction of renin-angiotensin-aldosterone system inhibitors, beta-blocking agents and the use of electrical devices. However, the prognosis of heart failure is still so disappointing that it remains the leading cause of death in developed countries. This grim record impels the search for new therapeutic strategies. The objective of this paper is to briefly review the results of some recent trials that have been put in place to test the effects of drugs that are deemed to be potentially capable of improving the prognosis of chronic systolic heart failure patients. Despite compelling theoretical premises, the results to date appear to be weak or even disappointing.

Low responsiveness to clopidogrel increases risk among CKD patients undergoing coronary intervention

Patients with CKD are at higher risk for major events after percutaneous coronary intervention (PCI) compared with subjects with normal renal function. The aims of this study were to evaluate responsiveness to clopidogrel in patients with CKD and to examine the effect of antiplatelet drug response on post-PCI outcome. We retrospectively evaluated a consecutive cohort of 1567 patients with symptomatic coronary artery disease undergoing PCI, 648 (41%) of whom had stage 3 to 5 CKD. We assessed responsiveness to clopidogrel by ADP-induced platelet aggregation after oral administration of a 600-mg clopidogrel loading dose and 100 mg of aspirin. In a multivariate survival analysis that included 1335 (85%) of the cohort, stage 3 to 5 CKD and low response to clopidogrel were independent predictors of the primary end point (composite of myocardial infarction, ischemic stroke, and death within 1 year). In summary, a low response to clopidogrel might be an additional risk factor for the poorer outcomes in patients with stage 3 to 5 CKD compared with patients with better renal function.

Pharmacotherapy of end-stage renal disease

IMPORTANCE OF THE FIELD

The incidence and prevalence of end-stage renal disease (ESRD) requiring renal replacement therapy (RRT) continues to grow worldwide. ESRD causes significant morbidity and mortality and has enormous financial and personal costs.

AREAS COVERED IN THIS REVIEW

Major electronic databases (including the Cochrane Library, MEDLINE and EMBASE) were searched from 1989 to September 2009 to summarize current pharmacotherapy of ESRD-associated complications in adults receiving maintenance dialysis (hemodialysis or continuous ambulatory peritoneal dialysis). Current guidelines for the treatment of ESRD (e.g., NKF-K/DOQI, KDIGO, and the ERA-EDTA's European Renal Best Practice Guidelines) were included.

WHAT THE READER WILL GAIN

Commonly used pharmacological treatment strategies for chronic arterial hypertension, anemia, iron management, dyslipidemia, hyperglycemia, and for disturbances of bone and mineral metabolism, including hyperphosphatemia and secondary hyperparathyroidism in ESRD, are presented. In addition, the reader will learn that nonadherence to oral medication in ESRD can contribute significantly to excess morbidity and mortality of the dialysis population.

TAKE HOME MESSAGE

Improvements in pharmacotherapy of ESRD may be at least in part counteracted by continuously increasing age and comorbid disease of the dialysis population. Individualized and tailor-made pharmacological management of the ESRD patient remains a challenge for the future.

Use of agents stimulating erythropoiesis in digestive diseases

Anemia is the most common complication of inflammatory bowel disease (IBD). Control and inadequate treatment leads to a worse quality of life and increased morbidity and hospitalization. Blood loss, and to a lesser extent, malabsorption of iron are the main causes of iron deficiency in IBD. There is also a variable component of anemia related to chronic inflammation. The anemia of chronic renal failure has been treated for many years with recombinant human erythropoietin (rHuEPO), which significantly improves quality of life and survival. Subsequently, rHuEPO has been used progressively in other conditions that occur with anemia of chronic processes such as cancer, rheumatoid arthritis or IBD, and anemia associated with the treatment of hepatitis C virus. Erythropoietic agents complete the range of available therapeutic options for treatment of anemia associated with IBD, which begins by treating the basis of the inflammatory disease, along with intravenous iron therapy as first choice. In cases of resistance to treatment with iron, combined therapy with erythropoietic agents aims to achieve near-normal levels of hemoglobin/hematocrit (11-12 g/dL). New formulations of intravenous iron (iron carboxymaltose) and the new generation of erythropoietic agents (darbepoetin and continuous erythropoietin receptor activator) will allow better dosing with the same efficacy and safety.

Oral anticoagulant therapy in hemodialysis patients: do the benefits outweigh the risks?

Managing oral anticoagulation may be difficult in hemodialysis patients because the antithrombotic effect can be counterbalanced by an increased risk of hemorrhagic complications. There is insufficient evidence to recommend the routine use of warfarin for thrombosis prophylaxis of the vascular access in all patients. If a decision for anticoagulation is made, dosing warfarin to a "therapeutic" level is suggested, although the most appropriate target INR range remains unclear. Many hemodialysis patients with atrial fibrillation have multiple risk factors for stroke and generally benefit from warfarin, with careful and frequent laboratory monitoring. Treatment with standard dose warfarin is also recommended in patients with venous thromboembolism provided that patients do not have contraindications to anticoagulation. For those with such contraindications, placement of an inferior vena cava filter is suggested. These recommendations are limited by the almost complete lack of data in dialysis patients. Sound randomized evidence of efficacy and harm for anticoagulation in these patients will likely never be available. Knowledge of the risk of bleeding and thrombosis in anticoagulated and nonanticoagulated dialysis patients could be provided by feasible, well-designed cohort studies.

Prognostic factors influencing the patency of hemodialysis vascular access: literature review and novel therapeutic modality by far infrared therapy

In Taiwan, more than 85% of patients with end-stage renal disease undergo maintenance hemodialysis (HD). The native arteriovenous fistula (AVF) accounts for a prevalence of more than 80% of the vascular access in our patients. Some mechanical factors may affect the patency of hemodialysis vascular access, such as surgical skill, puncture technique and shear stress on the vascular endothelium. Several medical factors have also been identified to be associated with vascular access prognosis in HD patients, including stasis, hypercoagulability, endothelial cell injury, medications, red cell mass and genotype polymorphisms of transforming growth factor-beta1 and methylene tetrahydrofolate reductase. According to our previous study, AVF failure was associated with a longer dinucleotide (GT)n repeat (n > or = 30) in the promoter of the heme oxygenase-1 (HO-1) gene. Our recent study also demonstrated that far-infrared therapy, a noninvasive and convenient therapeutic modality, can improve access flow, inflammatory status and survival of the AVF in HD patients through both its thermal and non-thermal (endothelial-improving, anti-inflammatory, antiproliferative, antioxidative) effects by upregulating NF-E2-related factor-2-dependent HO-1 expression, leading to the inhibition of expression of E-selectin, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1.

Role of oral iron in the management of long-term hemodialysis patients

BACKGROUND

The literature contends that oral iron supplementation is relatively ineffective in patients who are on long-term hemodialysis (HD), and intravenous iron is the superior form of supplementation.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Data were prospectively abstracted from a cross-sectional cohort of all patients in the long-term in-center HD program at St. Michael's Hospital (SMH) from April 1, 2003, to April 1, 2004. Laboratory data were measured monthly. SMH data were compared with those in eight other centers in the Toronto Region Dialysis Registry.

RESULTS

A total of 93% of the 151 patients tolerated oral iron. Eighty-eight (58%) patients received oral iron exclusively, and 60 (40%) patients received intravenous iron with or without oral iron. Of the patients who received oral iron exclusively, 73% maintained a hemoglobin of > or =110 g/L and 93% maintained a hemoglobin of > or =100 g/L. A total of 74% had an iron saturation > or =20%, and 36% had a ferritin level >100 g/L. Among the patients who were on oral iron alone and had hemoglobin of > or =110 g/L, the same amount of erythropoietin was used regardless of ferritin levels (P = 0.17), but less erythropoietin was used when they reached the target for either iron saturation or both iron indices (P = 0.02 and 0.03, respectively). Among the centers in the Toronto Region Dialysis Registry, hemoglobin levels and erythropoietin dosages did not differ among the three centers that predominantly used oral iron versus the six centers that predominantly use intravenous iron (P = 0.46 and 0.95, respectively).

CONCLUSIONS

Oral iron is a well-tolerated and effective form of iron supplementation in long-term HD patients.

Effects of smoking and blood eosinophil count on the development of arteriovenous fistulae thrombosis in hemodialysis patients

Arteriovenous fistulae (AVF) failure is the most common cause of morbidity and hospitalization in hemodialysis (HD) patients. The purpose of this study was to determine the effects of smoking and blood eosinophil count on the development of AVF thrombosis in HD patients. This cross-sectional study included 141 patients (M/F 80/61; age 43.4 +/- 11.6 years, HD duration 7.7 +/- 4.4 years). The following were analyzed as possible risk factors for AVF failure for all patients: demographic features, dialysis time, smoking, medications, body mass index, comorbid diseases, and various laboratory parameters (whole blood count and serum levels of albumin, calcium, phosphorus, uric acid, C-reactive protein, ferritin, and parathyroid hormone). AVF thrombosis was detected in 60 patients; in contrast, 81 patients had no thrombosis. Distributions of age, gender, and HD duration were similar between both groups. Univariate analysis showed that snuffbox AVF location (P < .0001), higher blood eosinophil count (P < .0001), smoking (P < .01), and higher hematocrit level (P < .05) were all associated with AVF thrombosis. According to multivariate analysis by logistic regression models, eosinophil count (RR = 1.005, P < .05) and snuffbox location (RR = 5.970, P < .05) were predictors of AVF thrombosis. When AVF location was excluded from the analysis, smoking (RR = 4.140, P < .01) and high blood eosinophil count (RR = 1.006, P < .005) were independent risk factors for thrombosis. Our study indicates that smoking and high blood eosinophil count may contribute to the development of AVF thrombosis.

Thromboembolism and anticoagulant management in hemodialysis patients: A practical guide to clinical management

The need for anticoagulation in dialysis patients is common and the incidence of venous thromboembolism (VTE) and atrial fibrillation in this population is high. While direct data are lacking on the management of anticoagulation in dialysis patients, careful weighing of risks and benefits on the basis of evidence from other populations is crucial. VTE should be managed with adjusted dose warfarin for most patients. Placement of an inferior vena cava filter is a reasonable option for those patients with unacceptable bleeding risks. Studies are ongoing to assess the safety of some low-molecular-weight heparins (LMWH), which may potentially be useful for long-term anticoagulation in hemodialysis patients. In atrial fibrillation the available data on risk of bleeding, risk of stroke, and patient preferences should all be taken into account when considering long-term anticoagulation. We have constructed an evidence model to help quantitate the risks and benefits for an individual patient. The impact of dialysis on risk of bleeding is such that the risk of bleeding will outweigh the benefit in many patients, and anticoagulation will not be used: in some of these patients aspirin therapy may be an alternative. Finally, in the area of prevention of graft and access thrombosis, some randomized controlled trials are available, but none have to date shown benefit from anticoagulation for primary or secondary prevention of thrombosis, and the risk of bleeding in these studies was high.

Reviews: Should the Target Hemoglobin for Patients with Chronic Kidney Disease Treated with Erythropoietic Replacement Therapy be Changed?

Recombinant human erythropoietin (rHuEPO, epoetin) revolutionized the treatment of anemia in patients with chronic kidney disease (CKD) when it was approved for use in the United States in 1989. Among dialysis patients, the mean hemoglobin (Hb) in patients undergoing dialysis rose from 7-8 g/dl prior to 1989 to 11-12 g/dl today. Among patients with CKD not on dialysis, epoetin use has not been as broadly applied as among dialysis patients, and although the mean Hb level in this patient population has increased, the impact has been less than in patients on dialysis. The optimal treatment target for epoetin remains controversial. Consistent with clinical practice guidelines, current practice in dialysis patients in the United States aims to maintain a target Hb of 11-12 g/dl, a level that is still well below the normal range. Debate centers on whether the current Hb target is too low and whether the target range is too narrow. Quality of life clearly improves in many individuals as Hb rises into the normal range from lower levels. In retrospective studies, higher Hb levels have been associated with lower risks of hospitalization and mortality. However, one large, prospective clinical trial has raised concern about normalizing Hb in hemodialysis patients with cardiac disease, and other prospective studies have not yet provided convincing evidence of significant benefits from normalizing Hb in dialysis-dependent and non-dialysis-dependent patients with CKD. A relative lack of information on non-dialysis-dependent patients with CKD and changes in fiscal policies regulating reimbursement for epoetin have contributed to uncertainty as to the best practices for anemia management in patients with CKD. There is increasing interest in the potential benefits of broadening the current target Hb range or eliminating an upper limit altogether and instead establishing a minimum Hb goal. While some extension of the upper limit of the currently recommended target Hb range might appear to be reasonable, the extent to which this should be extended, the benefits, risks, and costs of maintaining higher Hb levels in patients with CKD, and whether target Hb levels should be different in different CKD patient groups remains to be determined. Future efforts are likely to focus on selecting patient populations most likely to benefit from normalizing Hb, while adjusting the range of a subnormal Hb target for others.

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.

Incidence of arteriovenous thrombosis and the role of anticardiolipin antibodies in hemodialysis patients

INTRODUCTION

Fistula thrombosis in patients on maintenance hemodialysis is an important morbidity factor. Arterial or venous thrombotic events have been described as complications in patients on regular hemodialysis and positive titers of anticardiolipin antibodies (ACLA). This study was designed to evaluate the prevalence of ACLA in hemodialysis patients and it's relation to arteriovenous fistula (AVF) thrombosis.

METHODS

218 patients with AVF on maintenance hemodialysis were studied prospectively during a period of 14 months for any episode of AVF thrombosis (AVFT), after ACLA was assayed by ELISA in 171 ones. Other risk factors for thrombosis such as presence of diabetes, hypotension during dialysis, using of erythropoietin (rEpo), fistula site, gender, age, dialysis duration, and type of dialyser membrane were accessed.

RESULTS

56% of the patients had IgG ACLA = 10 GPL which was significantly correlated with dialysis duration (23.18 +/- 24.56 months in patients with ACLA = 10 GPL vs 37.73 +/- 36.35 months in patients with 20 = IgG ACLA < 40 GPL). Within 14 months follow up, 39 episodes of AVFT occurred in 34 patients (15.8%). Dialysis duration prior to start of study was 29.16 +/- 22.04 months. In our patients radiocephalic AVFs showed more thrombosis than brachiocephalic ones (23% vs 10%, p = 0.01 by Chi-square). Age more than 50 years old was a risk factor for AVFT (p = 0.034 by Chi-square). Also erythropoietin use (p = 0.011 by chi-square) and ultrafiltration more than 3 liters (average value of 14 months) were correlated with AVFT (p = 0.042 by Chi-square), but there wasn't any correlation between diabetes, presence of ACLA, hypotension during dialysis, gender, and dialysis membranes with AVFT. Ultimately, logistic regression analysis of factors associated with thrombosis was done and only fistula site (p = 0.015, O.R. = 2.87), and Eprex use (p = 0.031, O.R. = 4.05) showed significant correlation with AVFT.

CONCLUSION

Although incidence of anticardiolipin antibodies was high in our patients, we found no correlation between IgG ACLA and AVFT. Instead, we found that radiocephalic fistulas and Eprex injection were risk factors for AVFT.

Medical factors affecting patency of arteriovenous access

Arteriovenous access failure is multifactorial in nature with contributions from both medical and surgical etiologies. Medical causes of arteriovenous access failure are rare, and therefore infrequently identified as a major contributing source of malfunction. Although they account for only 10-15% of all cases of access failure, their importance should not be underestimated, especially in cases where a surgical source cannot be identified. Most medical causes are derived from Virchow's triad of endothelial cell injury, stasis, and hypercoaguability. Endothelial cell injury occurs through oxidative stress, activated platelets, increased levels of circulating tumor necrosis factor-alpha, and preexisting intimal hyperplasia. Stasis can occur through prolonged access compression, hypotension, or hypoalbuminemia. Finally, patients with renal failure requiring hemodialysis are frequently at increased risk for hypercoaguable states, except for situations of platelet dysfunction, and therefore access failure. Potential treatments include identifying and removing the offending source, as well as innovative, new medications to prevent their reoccurrence. Treatment is aimed at improving quality of life, as well as decreasing morbidity and hospital admissions in this difficult patient population.

Étude des effets directs et indirects de l’érythropoïétine dans un modèle expérimental de thrombose et de saignement chez le lapin

OBJECTIVES

To study direct and indirect effects of EPO on haemostasis.

STUDY DESIGN

Experimental, randomised.

ANIMALS

Forty-eight New Zealand rabbits.

METHOD

Animals were anaesthetised, ventilated and monitored continuously for blood pressure, heart rate, body temperature, and carotid blood flow variations and were randomised into four groups: control, EPO bolus 2400 IU kg(-1), fractionated EPO (one injection a week of 600 IU kg(-1) for 4 weeks), homologous red blood cell transfusion to reach the Ht level of the fractionated EPO group. A compression injury and a 75% stenosis of the carotid artery triggered a series of cyclic flow reductions (CFRs). CFRs were observed for a 20 min period in each group. Ear immersion bleeding time (BT) and hepato-splenic bleeding were performed at the end of the experiment. Biology was performed at the end of the thrombosis period: blood cells count, Hte, activated partial thromboplastin time, fibrinogen, arachidonic-induced platelet aggregation, EPO dosages.

RESULTS

No significant increase in thrombosis (CFRs) in the two EPO groups and in the transfused group. Increase in Hte in the fractionated EPO group versus control. Group EPO bolus: decrease in BT and hepato-splenic bleeding versus control; decrease in hepato-splenic bleeding versus fractionated EPO group, increase in platelet aggregation velocity versus control.

CONCLUSION

EPO did not increase the thrombotic risk in this rabbit model. EPO bolus decreased BT and hepato-splenic bleeding.

Increased incidence of symptomatic venous thrombosis in patients with cervical carcinoma treated with concurrent chemotherapy, radiation, and erythropoietin

BACKGROUND

Because studies have suggested that anemia has an adverse effect on outcome for patients with cervical carcinoma who are treated with radiation, recombinant human erythropoietin (rHuEpo) has been used increasingly to maintain hemoglobin levels in these patients. Erythropoietin may increase the risk of thrombosis. The authors performed a retrospective analysis to determine whether there was an increased rate of symptomatic venous thrombosis associated with the use of rHuEpo in patients with carcinoma of the uterine cervix and vagina.

METHODS

A retrospective, case-control study was performed on consecutive patients with localized carcinoma of the uterine cervix or vagina who were treated with chemotherapy and radiation (chemoradiotherapy). The primary outcome was symptomatic venous thrombosis.

RESULTS

One hundred forty-seven patients were reviewed. When they were divided into women who received rHuEpo (n = 75 patients) and women who did not receive rHuEpo (n = 72 patients), there were no significant differences in age, height, weight, disease stage, or body mass index. Fewer patients in the rHuEpo group required transfusions. In the rHuEpo group, 17 of 75 patients had either an upper extremity thrombosis (n = 12 patients) or a lower extremity thrombosis (n = 7 patients): 2 patients had both, and 2 patients had more than 1 event. Two of 72 patients who did not receive rHuEpo had symptomatic thrombosis. Patients who received rHuEpo had an odds ratio (OR) of developing thrombosis of 10.3 (95% confidence interval [95% CI], 2.3-46.2). Multiple logistic regression revealed that only the use of rHuEpo was associated with an increased risk of thrombosis (OR, 15.3; 95% CI, 3.1-76.7).

CONCLUSIONS

Patients with cervical carcinoma who received chemoradiotherapy and rHuEpo had an increased risk of symptomatic venous thrombosis.

The role of hyperparathyroidism, erythropoietin therapy, and CMV infection in the failure of arteriovenous fistula in hemodialysis

BACKGROUND

Vascular access failure is the main cause of morbidity in hemodialysis. Venous stenosis and subsequent thrombosis, as the result of intimal hyperplasia, is the major cause of vascular access failure. Intimal hyperplasia of the arteriovenous fistula (AVF) closely resembles the main histopathologic feature of atherosclerosis. In addition to the classic atherogenic risk factors, recently, cytomegalovirus (CMV) infection and parathyroid hormone (PTH) have been suggested as a potential cause of vascular disease.

METHODS

In the present study, we evaluated the relationship between AVF dysfunction and mean plasma PTH, cholesterolemia, high titer anti-CMV immunoglobulin G (IgG) (>250 U/mL), hematocrit, and mean erythropoietin (EPO) dose in 36 cases and 51 controls matched for age, time on dialysis, and type of AVF.

RESULTS

A higher percentage of patients with AVF failure had a smoking habit and presented high anti-CMV IgG titer. Patients with AVF failure had significantly higher mean plasma PTH, whereas the groups did not differ for mean cholesterolemia and hematocrit. Mean EPO dose was slightly, but significantly, higher in the AVF failure group. Multiple logistic regression revealed that smoking, EPO dose, elevated mean plasma PTH and high titer anti-CMV antibodies, significantly increased the risk of AVF dysfunction.

CONCLUSION

Our data suggest that hyperparathyroidism, smoking habits, CMV infection and EPO, independently of the hematocrit achieved, represent independent risk factors for hemodialysis access thrombosis.

Thrombosis in end-stage renal disease

Although renal failure has classically been associated with a bleeding tendency, thrombotic events are common among patients with end-stage renal disease (ESRD). A variety of thrombosis-favoring hematologic alterations have been demonstrated in these patients. In addition, "nontraditional" risk factors for thrombosis, such as hyperhomocysteinemia, endothelial dysfunction, inflammation, and malnutrition, are present in a significant proportion of chronic dialysis patients. Hemodialysis (HD) vascular access thrombosis, ischemic heart disease, and renal allograft thrombosis are well-recognized complications in these patients. Deep venous thrombosis and pulmonary embolism are viewed as rare in chronic dialysis patients, but recent studies suggest that this perception should be reconsidered. Several ESRD treatment factors such as recombinant erythropoietin (EPO) administration, dialyzer bioincompatibility, and calcineurin inhibitor administration may have prothrombotic effects. In this article we review the pathogenesis and clinical manifestations of thrombosis in ESRD and evaluate the evidence that chronic renal failure or its management predisposes to thrombotic events.

Past, present and future of erythropoietin use in the elderly

More than a decade has passed since the first patient with end-stage renal failure was treated with erythropoietin (EPO) and more than 85% of patients now receive this therapy. In the year 2002 more than 60% of dialysis patients will be elderly, and the treatment of anemia will be more complex due to the aditional causes: folate, iron and vitamin deficiency in this population. Correction of anemia with EPO brings about partial regression of left ventricular hypertrophy and some data suggest that such treatment reduces cardiovascular mortality in patients without advance cardiac disease. Normalization of hematocrit with EPO increases oxygen supply to the brain tissue with improvement in brain function. The improvement in the ability to recognize, discriminate and hold stimuli in memory for difficult tasks is particularly important for elderly people. No differences have been noted in the incidence of clotting of vascular access in patients treated with EPO compared with hemodialysis patients not so treated. Also no one has demostrated that treatment with EPO accelerates renal decline in patients with progressive renal insufficiency. In elderly people with anemia secondary to advanced renal failure, EPO therapy improves physical, cognitive and sexual function, and health related quality of life.

Should hemoglobin be normalized in patients with chronic kidney disease?

In the last decade the nephrology community has learned much about the impact of anemia on patients with kidney disease. Therapy of anemia can correct many of the symptoms which seriously compromise patient function. Despite the obvious benefits, controversy continues regarding the optimal target hemoglobin concentration both in patients prior to dialysis and in dialysis populations. In this editorial we review the clinical data that contribute to this controversy and the physiologic concepts underlying the treatment of anemia. Furthermore, we discuss the need to individualize hemoglobin targets for specific patient populations and the importance of early identification and treatment of anemia in patients with kidney disease. The economic impact of normalizing hemoglobin with the use of erythropoietin and intravenous or oral iron has affected clinical practice over the last decade. Current guidelines published by Kidney Disease Outcomes and Quality Initiative (KDOQI), the European Working Group on Anemia Management, and the Canadian Society of Nephrology all recommend target hemoglobin concentrations and thresholds for initiation of therapy and also suggest the need for reevaluation of current targets in light of new evidence. This editorial supports those guidelines and challenges the reader to critically evaluate current practice in the context of the accumulating data and the physiologic principles discussed herein. The therapy of anemia in patients with chronic kidney disease (CKD) is becoming increasingly sophisticated and is an essential component of care in patients with CKD. However, the effects of therapy will be most impressive when accompanied by the optimal care of all hemodynamic and metabolic abnormalities that are associated with CKD.

Venous thromboembolism in end-stage renal disease

Venous thromboembolic disease is considered an uncommon event in the end-stage renal disease (ESRD) population. We report five cases of venous thromboembolism (VTE) occurring in dialysis patients within a 1-year period at a single center. Analysis of these cases and review of the literature suggest that risk factors for VTE in the ESRD population are similar to those of the general population. Chronically ill, debilitated patients appear to be those most likely to develop VTE.

Elevated erythropoietin receptor and transforming growth factor-beta1 expression in stenotic arteriovenous fistulae used for hemodialysis

The issue of whether recombinant human erythropoietin (rhEPO) increases thrombosis of arteriovenous (AV) fistulae used for hemodialysis remains unclear. Thrombosis often occurs at stenotic segments of fistulae where there is marked intimal hyperplasia and extracellular matrix accumulation. Increased expression of transforming growth factor-beta1 (TGF-beta1) has been shown to be involved in the development of atherosclerotic lesions by promoting intimal hyperplasia and extracellular matrix accumulation. To clarify the role of rhEPO in the development of stenosis of AV fistulae, this study examined expression of the erythropoietin receptor (EPO-R), TGF-beta1, plasminogen activator inhibitor type 1 (PAI-1), cellular fibronectin containing an extra domain A (EDA+), and TGF-beta1 mRNA, and assessed in situ rhEPO binding in tissue specimens from seven cutaneous veins and eight patent and seven stenosed portions of AV fistulae of patients undergoing dialysis. Prominent intimal hyperplasia was evident in the stenosed segments. Significant elevation in expression of EPO-R and TGF-beta1 was noted in patent AV fistulae compared to the cutaneous veins. Significant enhancement of EPO-R and TGF-beta expression was detected in the stenotic fistulae. Fibronectin EDA+ and PAI-1 expression was increased in intimal hyperplasia compared to patent fistulae and cutaneous veins. Elevated EPO-R expression was further confirmed by in situ binding of biotin-labeled rhEPO in stenosed tissue specimens. It is hypothesized that increased rhEPO binding due to elevated EPO-R expression contributes to the development of AV fistula stenosis caused by intimal hyperplasia and extracellular matrix accumulation in response to increased TGF-beta1 expression in patients receiving hemodialysis.

Dialysis access failure: A sheep model of rapid stenosis

PURPOSE

Intimal hyperplasia at the venous anastomosis of dialysis access grafts causes early failure, although increased flow inhibits intimal hyperplasia in arterial grafts and after vessel injury. We designed a sheep model to study this process.

METHODS

Polytetrafluoroethylene (PTFE) grafts were placed in the necks of sheep from the carotid artery to the external jugular vein. Grafts were harvested after perfusion fixation at 4, 8, and 12 weeks and submitted for histologic and immunohistochemical examination, including morphometry of neointimal lesions.

RESULTS

The venous anastomoses developed thick neointima within the PTFE graft by 4 weeks. Lesions at the venous end were significantly thicker than those at the arterial end by 8 weeks (1.2 +/- 0.1 vs 0.38 +/- 0.05 mm, P <.02) and had greater cross-sectional area at both 4 (0.32 +/- 0.21 vs 3.6 +/- 0.8 mm(2), n = 7, P <.02) and 8 weeks (9.8 +/- 1.9 vs 1.1 +/- 0.7 mm(2), n = 7, P <.02). Only one of the four grafts (25%) in the 12-week group remained patent. Lesions were composed of smooth muscle cells, matrix, and thrombus of various ages. Cellular proliferation was prominent in neointima adjacent to thrombus and in granulation tissue surrounding the graft. Organizing thrombus contributed significantly to luminal narrowing.

CONCLUSION

The sheep model of dialysis access reliably produces venous stenosis within 4 weeks. Lesions develop in the absence of uremia, graft puncture, or dialysis, suggesting that these factors are not necessary for graft failure. The continued presence of thrombus and high rates of cellular proliferation suggest ongoing injury is an important cause of lesion formation. This model allows study of the cellular mechanisms of dialysis failure.

Effect of normalization of hematocrit on brain circulation and metabolism in hemodialysis patients

Full correction of anemia with recombinant human erythropoietin (rhEPO) has been reported to reduce the risk of cardiovascular morbidity and mortality and improve the quality of life in hemodialysis (HD) patients. Effects of normalization of hematocrit on cerebral blood flow and oxygen metabolism were investigated by positron emission tomography. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction ratio (rOER), and metabolic rate for oxygen (rCMRO2) were measured in seven HD patients before and after correction of anemia and compared with those in six healthy control subjects. In addition, blood rheology before and on rhEPO therapy was measured in HD patients, which included blood viscosity, plasma viscosity, erythrocyte fluidity, and erythrocyte aggregability. The results showed that plasma viscosity was high (1.51+/-0.19 mPa x s) and erythrocyte fluidity was low (85.8+/-4.8 Pa(-1) x s(-1)), while whole blood viscosity was within the normal range (3.72+/-0.38 mPa x s) before rhEPO therapy. After treatment, the hematocrit rose significantly from 29.3+/-3.3 to 42.4+/-2.2% (P<0.001), accompanied by a significant increase in the whole blood viscosity to 4.57+/-0.16 mPa x s, nonsignificant decrease in erythrocyte fluidity to 79.9+/-7.4 mPa(-1) x s(-1) and nonsignificant change in plasma viscosity (1.46+/-1.3 mPa x s). Positron emission tomography measurements revealed that by normalization of hematocrit, rCBF significantly decreased from 65+/-11 to 48+/-12 ml/min per 100 cm3 (P<0.05). However, arterial oxygen content (caO2) significantly increased from 5.7+/-0.7 to 8.0+/-0.4 mmol/L (P<0.0001), rOER of the hemispheres significantly increased from 44+/-3 to 51+/-6% (P<0.05) and became significantly higher than healthy control subjects (P<0.05). In addition, rCBV significantly increased from 3.5+/-0.5 to 4.6+/-0.6 ml/100 cc brain tissue. The results showed that oxygen supply to the brain tissue increased with normalization of hematocrit, but it was accompanied by increased oxygen extraction in the brain tissue. This may be assumed to be related to the decrease of erythrocyte velocity in the cerebral capillaries as a result of the decreased blood deformability and the increased plasma viscosity.

A comparison between PTFE and denatured homologous vein grafts for haemodialysis access: a prospective randomised multicentre trial. The SMASH Study Group. Study of Graft Materials in Access for Haemodialysis

OBJECTIVES

To compare patency and complication rates of polytetrafluoroethylene (PTFE) grafts and denatured homologous vein (DHV) grafts for long-term haemodialysis.

DESIGN

A prospective randomised multicentre trial.

MATERIALS

One hundred and thirty-one patients were enrolled between September 1994 and April 1997. Sixty-three DHV grafts and 68 PTFE grafts were implanted in 60 meals and 71 females. Complications and interventions were monitored. Patency rates, complication rates, and intervention rates of PTFE and DHV were compared.

RESULTS

The mean follow-up was 313 days for DHV (range 1-771) and 339 (3-909) days for PTFE. The total follow-up was 54.1 patient-years for DHV and 63.1 for PTFE. The 1-year primary patency rates were 30% and 40% for DHV and PTFE respectively. Secondary patency rate was 63% for both DHV and PTFE. Most frequent complication was thrombosis. A total of 75 thrombotic events (1.39 per patient-year) occurred in 35 (56%) DHV grafts and 78 (1.24 per py) in 36 (53%) PTFE grafts. A total of nine infections were seen in nine (14%) DHV grafts, whereas 21 infections in 20 (29%) PTFE grafts were seen (p = 0.08). All but one infected DHV graft could be salvaged with systemic antibiotics. In contrast, surgical intervention was necessary in nine PTFE grafts (p = 0.02). For aneurysms, eight DHV and two PTFE grafts needed revision (p = 0.03).

CONCLUSION

Patency rates between DHV and PTFE were not different. More infections were seen in PTFE grafts, and significantly more PTFE grafts needed surgical revision or removal because of infection. Significantly more DHV grafts were surgically revised or removed because of aneurysms.

Cardiac disease in chronic uremia: clinical outcome and risk factors

Cardiac disease is common and is the major killer in end-stage renal disease (ESRD). Cardiac failure is a highly malignant condition in ESRD patients. Cardiac failure mediates most of the adverse prognostic impact of ischemic heart disease. Left ventricular (LV) abnormalities are already present at initiation of dialysis therapy in approximately 80% of patients. These abnormalities (ie, systolic dysfunction in approximately 15%, LV dilatation with preserved systolic function in 30%, concentric LV hypertrophy [LVH] in 40%) independently predict ischemic heart disease and cardiac failure, and are the largest baseline predictor of mortality after 2 years on dialysis therapy. The associations between classical risk factors (eg, hyperlipidemia, smoking, hypertension) and cardiac outcomes in ESRD are inconsistent. "Uremic" risk factors represent a nascent, but potentially important field. In our prospective 10-year study of 433 patients starting renal replacement therapy, we identified the following as major independent risk factors for cardiac disease: (1) hypertension (concentric LVH, LV dilatation, ischemic heart disease, cardiac failure, inverse relationship with mortality); (2) anemia (LV dilatation, cardiac failure, death); and (3) hypoalbuminemia (ischemic heart disease, cardiac failure, death). Transplantation dramatically improved LV abnormalities, suggesting that a uremic environment is cardiotoxic. Multiple risk factors act in concert to produce cardiac disease in ESRD; many of these are avoidable, suggesting that the enormous burden of disease can be reduced considerably.

Evidence-based recommendations for the clinical use of recombinant human erythropoietin

In an era of increasing scrutiny regarding use of health care resources, it is critical that physicians have rational, evidence-based guidelines for treatment decisions. This review of more than 200 published papers constitutes a comprehensive approach to evaluating the current evidence regarding the clinical use of recombinant human erythropoietin therapy in renal failure patients. After this review, specific recommendations are provided regarding who should receive r-HuEPO; what the target hemoglobin should be; the best route of administration of r-HuEPO; how iron status should be evaluated and managed; and monitoring and follow-up of patients taking r-HuEPO. Throughout the article, areas for important future research are also identified.