Erythropoietin therapy improves graft patency with no increased incidence of thrombosis or thrombophlebitis

Association between Severe Anemia and Outcomes of Hemodialysis Vascular Access

BACKGROUND

The vast majority of patients undergoing hemodialysis (HD) are anemic. The severity of anemia in these patients may influence the postoperative outcomes and the durability of vascular access. Thus, the purpose of this study is to assess the association between anemia and adverse outcomes in patients undergoing HD access placement (arteriovenous grafts and fistula).

METHODS

Patients with chronic kidney disease stages IV and V recorded in the Vascular Quality Initiative Hemodialysis database between 2011 and 2017 were included. Patients were divided into 3 study groups based on preoperative hemoglobin (Hgb) levels: normal/mild anemia (Hgb: females ≥10 g/dL, males ≥12 g/dL), moderate anemia (Hgb: females: 7-9.9 g/dL, males: 9-11.9 g/dL), and severe anemia (Hgb: females<7 g/dL, males<9 g/dL). Multivariable logistic and Cox regression analyses were implemented to evaluate the association between anemia and 30-day mortality and primary patency (PP) at 1 year.

RESULTS

A total of 28,000 patients undergoing HD access surgery were identified (normal/mild [42%], moderate [49%], and severe [9%] anemia). Postoperative bleeding (2.1% vs. 2.2% vs. 2.2%) and 30-day outcomes including swelling (0.4% vs. 0.5% vs. 0.7%) and wound infection (0.4% vs. 0.3% vs. 0.1%) were similar in mild/normal, moderate, and severe anemia groups, respectively (All P > 0.05). However, 30-day mortality was significantly higher in patients with severe anemia compared with normal/mild and moderate anemia (2.1% vs. 1.1% and 1.1%, P < 0.001). After adjusting for potential confounders, severe anemia was associated with 90% higher risk of 30-day mortality (odds ratio [95% confidence interval]: 1.90 [1.20-3.00], P = 0.006) and 17% increase in PP loss at 1 year (adjusted hazard ratio [95% confidence interval]: 1.17 [1.02-1.35], P = 0.01) compared with the normal/mild anemia group. However, no significant difference was seen between normal/mild and moderate anemia.

CONCLUSIONS

In this large study of patients undergoing HD access placement, severe anemia was associated with 90% increased risk of 30-day mortality and 17% increased risk of loss of PP compared with those with normal/mild anemia. Management of severe anemia before surgery might be indicated to reduce operative mortality and improve the durability of HD access.

Preventing negative effects of smoking on microarterial anastomosis

Although microsurgery has rapid expanded, problems related to microarterial anastomosis continue. Cigarette smoking is one of the major risks for anastomosis by increasing platelet adhesion, and its effects on endothelial cells. Aim of this article is to study the negative effects of cigarettes on microarterial anastomosis line, and to investigate the protective effects of recombinant human erythropoietin (rHuEPO).Ninety-six Sprague-Dawley male rats were divided into 3 groups: group 1 was the control. Rats in groups 2 and 3 were exposed to cigarette smoke starting 21 days prior to surgery for 3 times a day. In group 3, additional 150 IU/kg rHuEPO was given via subcutaneously every 48 hours after microvascular anastomosis, femoral arterial samples, and blood samples were taken for assessment at 1st, 3rd, 5th, and 7th day. Intimae/media ratios were calculated for morphologic analyses.On morphologic analysis of femoral arteries there were statistically significant differences for all 3 groups at 1st, 3rd, 5th, and 7th days (P < 0, 05). The group that made differences was group 2, according to one-way analysis of variance within 3 groups in all days.Smoking decreases endothelial cells healing and causes more thromboses. rHuEPO can prevent these negative effects of smoking.

Primary Vascular Access

Primary vascular access is usually achievable by a distal autogenous arterio-venous fistula (AVF). This article describes the approach to vascular access planning, the usual surgical options and the factors affecting patency.

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.

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.

Acquired thrombophilic syndromes

As the biochemical mechanisms of hypercoagulable states are revealed, the syndromes of venous thromboembolism have been increasingly associated with specific aberrations. Most of these changes involve an increase in procoagulant potential, for example, by activation of the coagulation cascade, or by a defect or decrease in natural inhibitors of clotting. Similar abnormalities of the fibrinolytic pathways may contribute, as can loss of inhibitory mechanisms of endothelial cells, as well as changes in vascular anatomy and rheologic patterns of blood flow. All of these factors can directly influence thrombus formation and/or the physiologic response to the thrombus.(1)