Does the use of erythropoietin in hemodialysis patients increase dialysis graft thrombosis rates?

Perioperative management of facial reconstruction surgery in patients with end-stage renal disease undergoing dialysis

BACKGROUND

The rising incidence of dialysis-dependent end-stage renal disease (ESRD) has underscored the need for collaboration between plastic surgeons and nephrologists, particularly concerning preoperative and postoperative management for facial reconstruction. This collaboration is essential due to a scarcity of comprehensive information in this domain.

METHODS

A study initiated in January 2015 involved 10 ESRD cases on dialysis undergoing Mohs micrographic surgery for facial skin cancer, followed by reconstructive surgery under general anesthesia. To ensure surgical safety, rigorous measures were enacted, encompassing laboratory testing, nephrology consultations, and preoperative dialysis admission. Throughout surgery, meticulous control was exercised over vital signs, electrolytes, bleeding risk, and pain management (excluding nonsteroidal anti-inflammatory drugs). Postoperative assessments included monitoring flap integrity, hematoma formation, infection, and cardiovascular risk through plasma creatinine levels.

RESULTS

Adherence to the proposed guidelines yielded a notable absence of postoperative wound complications. Postoperative plasma creatinine levels exhibited an average decrease of 1.10 mg/dL compared to preoperative levels, indicating improved renal function. Importantly, no cardiopulmonary complications or 30-day mortality were observed. In ESRD patients, creatinine levels decreased significantly postoperatively compared to the preoperative levels (p< 0.05), indicating favorable outcomes.

CONCLUSION

The consistent application of guidelines for admission, anesthesia, and surgery yielded robust and stable outcomes across all patients. In particular, the findings support the importance of adjusting dialysis schedules. Despite the limited sample size in this study, these findings underscore the effectiveness of a collaborative and meticulous approach for plastic surgeons performing surgery on dialysis-dependent patients, ensuring successful outcomes.

The effects of vitamin E supplementation on malondialdehyde as a biomarker of oxidative stress in haemodialysis patients: a systematic review and meta-analysis

Background

Haemodialysis (HD) patients tend to have higher levels of oxidative stress (OS), associated with increased morbidity and premature mortality, compared to the general population. Levels of malondialdehyde (MDA), a biomarker of OS, are reduced by the antioxidant properties of vitamin E (VE) but outcomes from randomised control trials of VE supplementation on MDA in HD patients have been inconsistent.

Methods

We undertook a systematic review and meta-analysis of adult HD patients from VE supplementation studies with measures of MDA. The following search criteria of MEDLINE and EMBASE were considered from inception to January 2020: ‘dialysis’ AND ‘Vitamin E OR tocopherol’ AND ‘malondialdehyde OR MDA’. Two reviewers independently extracted study data and assessed risk of bias. Mean MDA levels and standard deviation were determined before and after VE supplementation. Standardised mean difference (SMD) and standard error were calculated as the within person difference and units of measure were not consistently recorded across all studies. The SMD were pooled using random effects meta-analysis.

Results

The SMD of MDA levels from 18 comparisons was significantly lower in HD patients following VE supplementation (− 1.55; confidence interval: − 2.17 to − 0.94, P < 0.00001). There were significant levels of heterogeneity between studies (I² value = 91%; P < 0.00001) with evidence of potential publication bias toward smaller studies.

Conclusions

Our findings support the use of VE to reduce the effects of OS in HD patients although high levels of heterogeneity and variation in the methodological approaches used by some studies highlight the need for further investigation.

Does discharge hemoglobin affect medium-term survival after coronary bypass?

BACKGROUND

the effect of discharge hemoglobin on survival of patients undergoing isolated coronary artery bypass grafting is unknown. Blood transfusion frequently confounds the issue.

METHODS

4682 consecutive patients undergoing isolated coronary artery bypass were studied. Univariate and multivariate analyses were performed to identify whether discharge hemoglobin was an independent risk factor determining survival after isolated coronary artery bypass. The analysis was complemented with a neuronal network.

RESULTS

univariate analysis identified discharge hemoglobin (p = 0.01) and blood transfusion (p < 0.0001) as significant factors affecting survival. Multivariate analysis identified age (p < 0.0001) ejection fraction (p < 0.0001), dialysis (p < 0.0001), peripheral vascular disease (p = 0.001), preoperative hemoglobin (p = 0.01), and blood transfusion (p = 0.0002) as significant factors determining survival. Neuronal network analysis confirmed the lack of importance of hemoglobin on discharge as a factor determining survival.

CONCLUSIONS

the discharge hemoglobin level does not affect medium-term survival.

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.

Optimal hematocrit based on regional cerebral blood flow in hemodialysis patients with diabetic nephropathy

BACKGROUND

The optimal hematocrit (Hctopt) in hemodialysis (HD) patients has yet to be determined based on the etiology and complications of their endstage renal disease (ESRD). To investigate this problem, we compared regional cerebral oxygen supply (rCOS) in diabetic (DM group) and non-diabetic HD patients (non-DM group) with data from subjects without renal disease or DM (control group)

METHODS

Regional cerebral blood flow (rCBF) was measured with single-photon emission computed tomography (SPECT) by the N-isopropyl-p-[(123)I]-iodoamphetamine ((123)I-IMP)-autoradiographic (ARG) method, and both the O2 content (O2CT) of arterial blood and hematocrit (Hct) were evaluated. Using the regression lines of rCBF vs Hct and O2CT vs Hct, we established a convex curve between rCOS and Hct. The peak of the curve indicates the maximum rCOS (rCOSmax) and Hctopt for rCOSmax

RESULTS

The rCBF in both the DM and non-DM groups was lower than that of the control group at the same Hct level, and the DM group had the lowest values. The rCOSmax values in the DM and non-DM groups were nearly equal, but both were lower than in controls. The Hctopt in the DM group was lower than that in the non-DM group by 6.3%±3.3%

CONCLUSIONS

Although the difference in Hctopt values in the DM and non-DM groups was 6.3%, the rCOSmax values in both groups were nearly equal. This suggests that differences in the Hctopt may depend on complications or causes of ESRD. The optimal Hct in the DM group was 22.6%±1.9%, and that for the non-DM group was 29.0%±1.8%

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)

Adapting the dialysis unit to increased hematocrit levels

Recombinant human erythropoietin (epoetin) therapy had a significant impact on the practice of nephrology before its widespread use in the dialysis arena. Since then, a number of long-term studies have provided physicians with parameters for optimizing therapeutic response and patient outcomes with epoetin therapy. Fears of accelerated hypertension syndromes or increased fistula clotting are recognized as largely unfounded. There is a marked improvement in well-being, as measured by both subjective and objective parameters, as the level of anemia is reduced. Fortunately, epoetin was recognized early as essential therapy in patients on dialysis and thus was reimbursed by the Health Care Financing Administration (HCFA) and other payers, albeit through various methods of payment. Why is it, then, that hematocrit levels are still averaging approximately 30%? Perhaps the basic concern that all practitioners share is the potential for increased morbidity at "higher" hematocrit levels. Increased access clotting was not reported in the recently completed Epogen (Epoetin alfa; Amgen Inc, Thousand Oaks, CA) phase IV postmarketing study. Needle size, however, needs to be considered, because higher blood flow rates accompanied by higher hematocrit levels may lead to increased hemolysis. The venous needle size is especially important in patients who experience large weight gains. It is important to keep these issues in mind as one decides on an appropriate hematocrit level for a given patient. Hull and Eschbach reviewed postdialysis data from patients with naturally occurring high hematocrit levels and found no major changes in hematocrit level, thus alleviating the concern of significant postdialysis inspissation as a common cause for fistula clotting.

The effect of comorbid conditions on hemodialysis access patency

Vascular access complications are a continuing source of hospitalization and morbidity in chronic dialysis patients. Several factors have been identified that are associated with complications in patients with native vein and prosthetic bridge arteriovenous graft fistulas. Early failure of native vein arteriovenous fistulas most consistently are related to small blood vessels. It remains unclear whether other comorbid factors play a role in complications of this fistula type. Prosthetic bridge fistulas are frequently placed in the United States and are associated with frequent complications. Factors most consistently associated with higher complication rates are diabetes mellitus, older age, and black race. Antiphospholipid antibody-associated syndromes and erythropoietin therapy have also been suggested as contributing factors. In addition, elevated lipoprotein(a) and hypoalbuminemia have been found to be associated with an increase of prosthetic graft thrombosis in white and Hispanic dialysis patients. This information strongly suggests that fistula complications are multifactorial. An improved understanding of the mechanisms of these associations may aid in the delineation of the pathogenesis and an improvement in the outcome of this important problem.