Effects of hemodialysis and long-term erythropoietin treatment on protein C, and on free and total protein S

2017 consensus of the Asia Pacific Heart Rhythm Society on stroke prevention in atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia, causing a 2-fold increase in mortality and a 5-fold increase in stroke. The Asian population is rapidly aging, and in 2050, the estimated population with AF will reach 72 million, of whom 2.9 million may suffer from AF-associated stroke. Therefore, stroke prevention in AF is an urgent issue in Asia. Many innovative advances in the management of AF-associated stroke have emerged recently, including new scoring systems for predicting stroke and bleeding risks, the development of non-vitamin K antagonist oral anticoagulants (NOACs), knowledge of their special benefits in Asians, and new techniques. The Asia Pacific Heart Rhythm Society (APHRS) aimed to update the available information, and appointed the Practice Guideline sub-committee to write a consensus statement regarding stroke prevention in AF. The Practice Guidelines sub-committee members comprehensively reviewed updated information on stroke prevention in AF, emphasizing data on NOACs from the Asia Pacific region, and summarized them in this 2017 Consensus of the Asia Pacific Heart Rhythm Society on Stroke Prevention in AF. This consensus includes details of the updated recommendations, along with their background and rationale, focusing on data from the Asia Pacific region. We hope this consensus can be a practical tool for cardiologists, neurologists, geriatricians, and general practitioners in this region. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician׳s decision remains the most important factor in the management of AF.

Soluble P-Selectin During a Single Hemodialysis Session in Patients With Chronic Renal Failure and Erythropoietin Treatment

In several studies, hemodialysis (HD) patients treated with recombinant human erythropoietin (rHuEPO) because of renal anemia showed increased levels of soluble adhesion molecules. The purpose of the study was to investigate the changes of soluble P-selectin (sSELP) and its relationship to platelet activation during a single HD session in patients with long-term rHuEPO treatment. Fifty-two HD patients with chronic renal failure were involved—26 with rHuEPO treatment (EPO group) and 26 without (non-EPO group). Thirty healthy subjects served as the control group. The sSELP, β-thromboglobulin, and platelet factor 4 plasma levels were measured before and after a single 4-hour HD session on a cuprophane dialyzer. The basal β-thromboglobulin and platelet factor 4 plasma levels were significantly increased in both HD groups compared with healthy controls but did not change after a single HD session, except for a significant decrease of platelet factor 4 in the non-EPO group. The predialysis sSELP plasma levels did not differ significantly compared with those of the healthy controls, but there was a significant increase of sSELP levels after a single HD session in both groups (EPO, P < .005; non-EPO, P < .05, respectively). These results suppose that the increased sSELP level was released from platelets during the course of a single HD session. The more significant increase of the sSELP plasma levels in EPO group during HD indicates that platelets are more activated in patients with long-term rHuEPO treatment, and this fact could partially explain the suspected tendency for thrombosis in these patients.

Prothrombotic changes in platelet, endothelial and coagulation function following hemodialysis

PURPOSE

Patients on hemodialysis (HD) have an increased risk of thrombotic events, including myocardial infarction and vascular access thrombosis. The study hypothesis is that a single session of dialysis leads to platelet, endothelial and coagulation activation. Our aim is to determine the effect of a single HD session on prothrombotic vascular biomarkers before and after a single session of hemodialysis.

METHODS

Blood samples were taken from the vascular access of 55 patients immediately before and after a hemodialysis session. Platelet function was assessed by (1) flow cytometric measurement of P-selectin expression and fibrinogen binding +/- ADP stimulation, (2) Ultegra rapid platelet function assay (RPFA) using the agonists thrombin receptor activating peptide (TRAP) and arachidonic acid (AA), (3) soluble P-selectin, and (4) soluble CD40L. Coagulation (thrombin-antithrombin III [TAT] and D-dimer), endothelial von Willebrand factor (vWF) and high sensitivity C-Reactive protein (hsCRP) were assessed by ELISA.

RESULTS

Unfractionated heparin was given to all patients during dialysis and 30 patients (55%) were on antiplatelet agents. Post-hemodialysis there were significant increases in unstimulated platelet P-selectin (p=.037), stimulated P-selectin (p<.001), soluble P-selectin (p<.001) and soluble CD40L (p=.036). Stimulated platelet fibrinogen binding was increased post-hemodialysis (p<.001) but unstimulated fibrinogen binding was unchanged. TRAP- (p<.001] and AA-(p=.009) stimulated aggregation were reduced post-hemodialysis. There were increases post-hemodialysis in TAT (p<.001), D-dimer (p<.001), vWF (p<.001) and hsCRP (p=.011).

CONCLUSION

This study has shown that despite heparin therapy, a single session of HD induced increases in platelet, endothelial, and coagulation activation. More effective medical strategies to reduce the prothrombotic state of patients on hemodialysis should be investigated.

Protein Z and natural anticoagulants in children on peritoneal dialysis and hemodialysis

Hemostatic alterations due to abnormalities in the coagulation and fibrinolytic system may occur in dialysis patients. Protein Z (PZ) is a vitamin K-dependent coagulation protein promoting assembly of thrombin with phospholipid vesicles. The aim of this study was to investigate PZ and natural anticoagulants in children on hemodialysis (HD) and peritoneal dialysis (PD). Protein Z, protein C (PC), protein S (PS), antithrombin III (AT III), and fibrinogen levels were studied in 24 PD, 13 HD patients and 23 controls. Plasma PZ levels in patients on HD were significantly higher than those on PD and control group (p = 0.04, p = 0.03). We observed elevated PC, PS and AT III activities in children on PD when compared to controls (p = 0.011, p = 0.003, p < 0.001). In HD patients, only PS activity was increased compared to controls (p = 0.016). PC and PS activities did not differ between PD and HD patients whereas AT III activity was higher in PD patients compared to HD patients (p < 0.001). Normal/high levels of PC, PS and AT III suggest that children on PD or HD treatment do not seem to have an increased risk of thrombogenesis due to reduction of these proteins. Increased PZ levels, however, might contribute to the hemostatic alterations in children on HD treatment along with other well known abnormalities.

Physiologic inhibitors of coagulation in patients on chronic hemodialysis

Patients on hemodialysis are at increased risk for bleeding and thromboses. The intriguing balance between these risks is more complex than once thought, as endogenous clotting factors and their regulators come into contact with bioincompatible dialyzer membranes, in the setting of an extracorporeal circuit of blood flow, in the face of the uremic state. In this review, we summarize the current data on the interaction between the physiologic inhibitors of coagulation and hemodialysis. Data sources and study selection were obtained from research and review articles related to the endogenous anticoagulation pathway published in English on MEDLINE from 1972 to 2002. While protein C activity and protein S antigen concentrations are increased, there is no change in antithrombin III levels during hemodialysis in relation to predialysis levels. Plasma protein Z, which has only recently been studied in uremic subjects, is increased as well. In addition, hemodialysis leads to elevated tissue factor plasminogen inhibitor, thrombomodulin, tissue plasminogen activator, and plasminogen activator inhibitor-1 activities. The potential functional significance of these observations is discussed. Finally, as erythropoietin is commonly prescribed to uremic patients and is recognized to be prothrombotic, an appraisal of its interaction with the naturally occurring anticoagulants is presented. It is apparent that we are only beginning to realize the complexity of the interplay between this myriad of serum factors and hemodialysis. Further research is needed to shed light on this underexplored area of hemodialysis.

Erythropoietin-induced recurrent veno-occlusive priapism associated with end-stage renal disease

This is the first report of a male hemodialysis patient experiencing recurrent dialysis-associated priapism that resolved when his concurrent erythropoietin dose was reduced from 2000 to 1500 U one time per week and held if his hemoglobin was greater than 10 g/dL. We discuss dialysis-associated priapism and the effects of erythropoietin on the coagulation cascade and male hormone levels in an effort to elucidate the etiology of priapism in this patient.