Activation of Coagulation During Hemodialysis: Effect of Blood Lines Alone and Whole Extracorporeal Circuit

Impact of renal replacement therapy modality on coagulation and platelet function in critically ill patients: A prospective observational study

BACKGROUND

Renal replacement therapy (RRT) may affect coagulation and platelet function in critically ill patients. However, the mechanism and the difference in the impact on coagulation between intermittent hemodialysis (iHD) and continuous renal replacement therapy (CRRT) remains unclear. This study aimed to investigate and compare the impact of iHD and CRRT on coagulation and platelet function.

METHODS

Critically ill patients undergoing RRT were classified into the iHD group or the CRRT group. After the first blood sampling, patients underwent either a single session of hemodialysis or 48 h of CRRT, then a second blood sample was taken. Rotational thromboelastometry (ROTEM), platelet aggregometry and conventional coagulation tests were performed. The primary outcome was a change in extrinsically activated ROTEM (EXTEM) clotting time (CT).

RESULTS

60 dialysis sessions from 56 patients were finally included, with 30 dialysis sessions per group. EXTEM CT was prolonged significantly after dialysis in the iHD group (90 [74, 128] vs. 74 [61, 91], p < 0.001), but did not change in the CRRT group (94.4 ± 29.4 vs. 91.6 ± 22.9, p = 0.986). The platelet aggregation did not change after both iHD and CRRT. A change in EXTEM CT was significantly greater in the iHD group compared to the CRRT group (p = 0.006). The difference in the incidence of bleeding events was insignificant between the two groups (p = 0.301).

CONCLUSIONS

EXTEM CT was significantly prolonged after iHD, but this change was not shown after CRRT. Platelet function was not affected by both dialysis modalities.

Development and Validation of a Coagulation Risk Prediction Model for Anticoagulant-Free Hemodialysis: Enhancing Hemodialysis Safety for Patients

INTRODUCTION

This study aimed to develop and validate a risk prediction model for predicting the likelihood of coagulation in patients undergoing anticoagulant-free hemodialysis (HD). Anticoagulant-free HD technique is necessary in patients with contraindications to systemic therapy. Coagulation is a complication of this technique. Unfortunately, no predictive model is currently available to assess the risk of coagulation in anticoagulant-free HD.

METHODS

We retrospectively analyzed the clinical data from 299 HD sessions involving 164 patients who underwent anticoagulant-free HD between January 2022 and June 2023. To identify the risk factors for coagulation in anticoagulant-free HD, a univariate analysis was performed on 18 independent variables. Logistic regression was used to establish predictive models by identifying factors contributing to coagulation in anticoagulant-free HD. A calibration curve was drawn using regression coefficients and 1,000 bootstrap repetitions to validate our model internally. The performance of the prediction model was evaluated using receiver operating characteristic, area under the curve (AUC), and decision curve analysis (DCA).

RESULTS

The incidence of coagulation in patients on anticoagulant-free HD was 35.1%. Logistic regression analysis showed that platelet (PLT), hematocrit (HCT) levels, dialysate type, and age were risk factors for coagulation in anticoagulant-free HD patients (p < 0.05). The Hosmer-Lemeshow test showed p = 0.29, and the AUC is 0.76 (95% CI 0.70-0.80). The optimal critical value was 0.40, yielding a sensitivity of 61.0%, a specificity of 80.4%, and a Youden index of 0.41.

CONCLUSION

In anticoagulant-free HD, there were numerous risk factors and a 35.1% occurrence of coagulation. The constructed coagulation risk prediction model exhibited good predictive and clinical utility and could serve as a reference for the initial assessment and screening of coagulation risk in anticoagulant-free HD.

Hemoincompatibility in Hemodialysis-Related Therapies and Their Health Economic Perspectives

Hemobiologic reactions associated with the hemoincompatibility of extracorporeal circuit material are an undesirable and inevitable consequence of all blood-contacting medical devices, typically considered only from a clinical perspective. In hemodialysis (HD), the blood of patients undergoes repetitive (at least thrice weekly for 4 h and lifelong) exposure to different polymeric materials that activate plasmatic pathways and blood cells. There is a general agreement that hemoincompatibility reactions, although unavoidable during extracorporeal therapies, are unphysiological contributors to non-hemodynamic dialysis-induced systemic stress and need to be curtailed. Strategies to lessen the periodic and direct effects of blood interacting with artificial surfaces to stimulate numerous biological pathways have focused mainly on the development of 'more passive' materials to decrease intradialytic morbidity. The indirect implications of this phenomenon, such as its impact on the overall delivery of care, have not been considered in detail. In this article, we explore, for the first time, the potential clinical and economic consequences of hemoincompatibility from a value-based healthcare (VBHC) perspective. As the fundamental tenet of VBHC is achieving the best clinical outcomes at the lowest cost, we examine the equation from the individual perspectives of the three key stakeholders of the dialysis care delivery processes: the patient, the provider, and the payer. For the patient, sub-optimal therapy caused by hemoincompatibility results in poor quality of life and various dialysis-associated conditions involving cost-impacting adjustments to lifestyles. For the provider, the decrease in income is attributed to factors such as an increase in workload and use of resources, dissatisfaction of the patient from the services provided, loss of reimbursement and direct revenue, or an increase in doctor-nurse turnover due to the complexity of managing care (nephrology encounters a chronic workforce shortage). The payer and healthcare system incur additional costs, e.g., increased hospitalization rates, including intensive care unit admissions, and increased medications and diagnostics to counteract adverse events and complications. Thus, hemoincompatibility reactions may be relevant from a socioeconomic perspective and may need to be addressed beyond just its clinical relevance to streamline the delivery of HD in terms of payability, future sustainability, and societal repercussions. Strategies to mitigate the economic impact and address the cost-effectiveness of the hemoincompatibility of extracorporeal kidney replacement therapy are proposed to conclude this comprehensive approach.

Hemodialysis without Systemic Anticoagulation: A Randomized Controlled Trial to Evaluate Five Strategies in Patients at a High Risk of Bleeding

BACKGROUND

There has been growing interest in exploring combined interventions to achieve a more effective heparin-free treatment approach.

AIM

to evaluate combination of interventions compared to standard practice (intermittent flushes) to prevent clotting and consequently reduce premature interruptions of hemodialysis.

METHODS

This open-label randomized controlled trial recruited chronic hemodialysis patients with contra-indication to systemic heparinization. Participants were randomized into one of five groups to receive different strategies of heparin-free hemodialysis treatment for up to three sessions.

PRIMARY ENDPOINT

the successful completion of hemodialysis without clotting.

SECONDARY OUTCOMES

the clotting of the air traps assessed by a semi-quantitative scale, online KT/V, and safety of the interventions.

RESULTS

Forty participants were recruited and randomized between May and December 2020. Participants showed similar baseline biochemistry results and coagulation profiles. The highest success rates were observed in group 3 (heparin-coated dialyzers combined with intermittent flushes) (100%) and group 5 (hemodiafiltration with online predilution combined with heparin-coated dialyzers), with 91% vs. the control (intermittent flushes) (64%). Group 2 (heparin-coated dialyzers alone) had the poorest success rate, with 38% of the sessions being prematurely terminated due to clotting. KT/V and clotting scores were similar between groups. No adverse events related to the trial interventions were observed.

CONCLUSIONS

The proposed combination of interventions may have had additive effects, leading to less frequent clotting and the premature termination of an HD/HDF session. Our study supports the feasibility of conducting a larger randomized controlled trial focusing on the efficacy of combined interventions for heparin-free HD in patients with a high risk of bleeding.

The effects of medium cut-off and high-flux membranes on activated clotting time of patients on hemodialysis

Introduction

The interaction between blood and dialysis membrane increases the risk of clot formation. Membrane properties can interfere with coagulation activation during dialysis. Heparin is usually used to ensure anticoagulation, which can be monitored by the Activated Clotting Time (ACT) test. The purpose of this study was to compare the ACT of patients with chronic kidney disease (CKD) undergoing hemodialysis with high-flux (HF) and medium cut-off (MCO) membranes.

Methods

This is a prospective, randomized, crossover study in which 32 CKD patients were dialyzed for 12 weeks with each membrane. Blood clotting measured by ACT was evaluated at the beginning, 2nd, and 4th hour of the dialysis session. Throughout the study, there were no changes in the dose or administration method of heparin.

Results

Patients mainly were middle-aged, non-black males on hemodialysis for eight years. Before randomization, ACT values were 132 ± 56, 195 ± 60, and 128 ± 32 seconds at pre-heparinization, 2nd and 4th hour, respectively. After 12 weeks, ACT values in HF and MCO groups were 129 ± 17, 205 ± 65 and 139 ± 38 seconds, and 143 ± 54, 219 ± 68 and 142 ± 45 seconds, respectively. An ANOVA model adjusted and unadjusted for repeated measures showed a significant time but no treatment or interaction effects. In an additional paired-sample analysis, no difference between ACT values of HF and MCO Groups was observed.

Discussion and Conclusion

There was no difference regarding the ACT test during dialysis therapy using HF or MCO membranes. This data suggests that no adjustment in the dose or administration method of heparin is necessary with the use of MCO dialysis membranes.

Effect of dialyzer geometry on coagulation activation in the extracorporeal circuit in maintenance hemodialysis patients: Prospective randomized trial

BACKGROUND AND OBJECTIVES

The coagulation cascade is activated during hemodialysis (HD) due to interaction of blood with the dialysis circuit. There is a paucity of data on the effect of the physical structure of the dialyzers on coagulation activation during HD. We conducted this study to compare the effect of Helixone FX80 versus Platinum H4 dialyzers on coagulation activation during HD.

METHODS

Twenty patients on maintenance HD were enrolled in this randomized prospective crossover study. Each patient was dialyzed using Helixone FX80 and Platinum H4 dialyzers. Serum thrombin-antithrombin complex (TAT) was measured before (T0h) and at the end (T4H) of HD.

RESULTS

The absolute changes of serum TAT were comparable with the two dialyzers (median [IQR]: 1.15 [0.65, 1.75] for Helixone FX80 vs. 1.15 [0.67, 2.05] for Platinum H4, p = 0.371).

CONCLUSION

Helixone FX80 and Platinum H4 dialyzers have similar effects on coagulation activation during HD.

Effect of Near-Infrared Blood Photobiomodulation on Red Blood Cell Damage from the Extracorporeal Circuit during Hemodialysis In Vitro

The contact of blood with the bioincompatible membranes of the dialyzer, which is part of the extracorporeal circuit during hemodialysis (HD), causes upregulation of various cellular and non-cellular processes, including massive generation and release of reactive oxygen species (ROS), (which is one of the primary causes of anemia in chronic renal failure). We hypothesize that near-infrared (NIR) radiation possesses antioxidant properties and is considered to protect the red blood cell (RBC) membrane by enhancing its resilience to negative pressures. Our experimental setup consisted of an HD machine equipped with a dialyzer with a polyamide membrane; whole bovine blood was examined in vitro in blood-treated circulation. Blood samples were taken at 0, 5, 15, and 30 min during the HD therapy. We also assessed osmotic fragility, hematocrit, hemolysis, and oxidative stress as a concentration of reactive thiobarbituric acid substances (TBARS). Our results have shown that RBC membrane peroxidation increased significantly after 30 min of circulation, whereas the TBARS level in NIR-treated blood remained relatively steady throughout the experiment. The osmotic fragility of NIR-irradiated samples during dialysis was decreased compared to control samples. Our studies confirm that in vitro, blood photobiomodulation using NIR light diminishes oxidative damage during HD and can be considered a simultaneous pretreatment strategy for HD.

Joint Deep-Learning-Enabled Impact of Holistic Care on Line Coagulation in Hemodialysis

In order to investigate the impact of holistic care on line coagulation and safety in hemodialysis and to address limitations of the conventional ultrasound flow vector imaging (VFM) technique, which requires proprietary software to acquire raw Doppler and scatter tracking data, a combined deep-learning-enabled holistic care approach to line coagulation in hemodialysis is proposed. First, velocity along the direction of the sound beam, which is provided by the color Doppler echocardiogram, is obtained as the radial velocity component using a velocity scale. Moreover, the left ventricular wall contour is automatically identified using a U-Net network and the left ventricular wall velocity is calculated as the boundary condition of continuity equation by a retrained PWC-Net model. Likewise, the velocity component of each blood mass in the vertical direction of the sound beam is obtained by solving the continuity equation (i.e. tangential velocity component). Finally, the velocity vector map of cardiac flow field was synthesized and visualized in the flow diagram. For this purpose, sixty patients admitted to receive hemodialysis from February 2019 to June 2020 were randomly divided into two groups of 30 patients where the control group implemented conventional care and the study group implemented all-round care on the basis of conventional care. The nursing effects of both groups were compared. Incidence of pipeline coagulation and complications in the study group were lower than those in the control group and the difference was statistically significant (P < 0.05). The nursing detail score, nursing attitude score, nursing professionalism score, and total satisfaction score in the study group were higher than those in the control group and the difference was statistically significant (P < 0.05). Applying all-round nursing in hemodialysis can effectively reduce the incidence of line coagulation complications and improve the safety of hemodialysis, as well as improve patients' satisfaction with nursing care.

How biocompatible haemodialysers can conquer the need for systemic anticoagulation even in post-dilution haemodiafiltration: a cross-over study

Background

While systemic anticoagulation is most widely used in haemodialysis (HD), contraindications to its use might occur in particular settings. The Solacea^™ haemodialyser with an asymmetric triacetate membrane claims improved biocompatibility and has already shown promising results when used in combination with only half dose of anticoagulation. To quantify the performance of the Solacea^™ when further decreasing anticoagulation to zero, fibre blocking was assessed by micro-computed tomography (micro-CT).

Methods

Ten maintenance HD patients underwent six dialysis sessions at midweek using a Solacea^™ 19H dialyser, consecutively in pre-dilution haemodiafiltration (pre-HDF), HD and post-dilution HDF (post-HDF). After the first three sessions with only a quarter of their regular anticoagulation dose (one-quarter), the last three sessions were performed without anticoagulation (zero). Dialyser fibre blocking was quantified in the dialyser outlet potting using a 3D micro-CT scanning technique post-dialysis.

Results

Even in case of reduced (one-quarter) anticoagulation, the relative number of open fibres post-dialysis was almost optimal, i.e. 0.96 (0.87-0.99) with pre-HDF, 0.99 (0.97-0.99) with HD and 0.97 (0.92-0.99) with post-HDF. Fibre patency was mildly decreased for pre-HDF and HD when anticoagulation was decreased from one-quarter to zero, i.e. to 0.76 (0.61-0.85) with pre-HDF (P = 0.004) and to 0.80 (0.77-0.89) with HD (P = 0.013). Comparing the results for zero anticoagulation, post-HDF [i.e. 0.94 (0.82-0.97)] performed as well as HD and pre-HDF.

Conclusions

The Solacea^™ dialyser provides promising results for use in conditions where systemic anticoagulation is contraindicated. Post-HDF, although inducing haemoconcentration in the dialyser, is equally effective for fibre patency in case of zero anticoagulation as pre-HDF and HD when using Solacea^™.

Ultrathin and Robust Hydrogel Coatings on Cardiovascular Medical Devices to Mitigate Thromboembolic and Infectious Complications

Thromboembolic and infectious complications stemming from the use of cardiovascular medical devices are still common and result in significant morbidity and mortality. There is no strategy to date that effectively addresses both challenges at the same time. Various surface modification strategies (e.g., silver, heparin, and liquid-impregnated surfaces) are proposed yet each has several limitations and shortcomings. Here, it is shown that the incorporation of an ultrathin and mechanically robust hydrogel layer reduces bacterial adhesion to medical-grade tubing by 95%. It is additionally demonstrated, through a combination of in vitro and in vivo tests, that the hydrogel layer significantly reduces the formation and adhesion of blood clots to the tubing without affecting the blood's intrinsic clotting ability. The adhesion of clots to the tubing walls is reduced by over 90% (in vitro model), which results in an ≈60% increase in the device occlusion time (time before closure due to clot formation) in an in vivo porcine model. The advantageous properties of this passive coating make it a promising surface material candidate for medical devices interfacing with blood.

Hemodialysis without anticoagulation: Less clotting in conventional hemodialysis than in predilution hemodiafiltration

INTRODUCTION

Hemodialysis patients with contraindication to systemic anticoagulation require a heparin-free hemodialysis technique. Among several alternatives to heparin, predilution hemodiafiltration (HDF) is often used, albeit without any confirmation of its effectiveness.

METHODS

Patients hospitalized in a nephrology ICU and hemodialysed for stage 5 CKD or AKI and with contraindication to systemic anticoagulation were randomized to either standard HD with a polysulfone membrane, or to predilution HDF with the same membrane. Coagulation activation was evaluated clinically by the need for premature termination and by the measurement of D-dimers.

FINDINGS

Two hundred dialysis sessions were performed in 155 patients. Survival curves showed better circuit survival in HD (P = 0.046). In HD, 12% of sessions were interrupted for coagulation versus 23% in predilution HDF (P = 0.04).

DISCUSSION

Predilution HDF was associated with more premature clotting than conventional HD without improvement in dialysis duration or performance epuration indices. When aiming for a 4-hour duration session, conventional heparin-free hemodialysis can be safely proposed in most patients with high bleeding risk.

Antithrombotic properties of hemofilter coated with polymer having a hydrophilic blood-contacting layer

OBJECTIVE:

Extracorporeal circulation devices are coated with a biocompatible polymer coating agent (BPCA) that has a hydrophilic blood-contacting layer, but hemofilters are not. We aimed to investigate the antithrombotic properties of a BPCA-coated hemofilter.

METHODS:

Four experiments using BPCA-coated circuits and non-coated hemofilters and four experiments using BPCA-coated circuits and BPCA-coated hemofilters were performed with whole human blood and compared by measuring the circuit pressure every 5 min, antithrombin activity every 40 min, and thrombin-antithrombin complex every 40 min, for a total of 240 min of recirculation.

RESULTS:

The mean time required for the pressure at the inlet of the hemofilter to increase sharply was longer in BPCA-coated than in non-coated hemofilters (66 ± 11 min vs 25 ± 9 min, p < 0.01). The mean antithrombin activity value at 200 and 240 min of recirculation was significantly higher in the experiments with BPCA-coated versus non-coated hemofilters (43.3 ± 2.87 vs 33.3 ± 5.74, p = 0.04; 42.8 ± 3.59 vs 31.0 ± 5.35, p = 0.01, respectively); the antithrombin activity values at the other time points were not significantly different. Furthermore, all thrombin-antithrombin complex values in experiments with the BPCA-coated hemofilters achieved overrange at 80 min of recirculation, whereas those with the non-coated hemofilter achieved overrange at 40 min.

CONCLUSION:

This study suggests that BPCA-coated hemofilters can inhibit antithrombin consumption, contributing to antithrombotic effects in extracorporeal circulation circuits.

Heparin-free renal replacement therapy for chronic hemodialyzed patients at high risk for bleeding: a comparison of on-line predilution hemodiafiltration with conventional hemodialysis

BACKGROUND

In chronic hemodialysis patients with high risk of bleeding, optimal anticoagulation of the extracorporeal circuit is challenging. Heparin-free hemodialysis (HD) with heparin-coated AN69ST dialyzer is now considered as a good option and recommended by experts. Predilutional hemodiafiltration (HDF) may represent also a feasible alternative but has been poorly investigated. In this study, our aim was to evaluate the performance of on-line automated predilution heparin-free HDF as compared to conventional heparin-free HD with a heparin-coated membrane.

METHODS

We prospectively studied chronic hemodialysis patients at high risk of bleeding consecutively admitted to hospital who underwent heparin-free renal replacement therapy (RRT) in our nephrology department. During 1 year, we routinely used heparin-free HD and on-line HDF in these settings. By using a propensity score, we compared HDF to HD regarding to session failure and efficiency.

RESULTS

One hundred and seventy-nine patients were included in the study. Clotting phenomena necessitating premature termination of RRT sessions were encountered in 19% of them. After propensity score matching, the comparison of 77 HD and 77 HDF sessions showed no significant differences in duration of the sessions and in dialyzer clotting. By multivariate analysis, a blood flow less than 250 mL/min and recent surgery were the only parameters associated with extracorporeal circuit thrombosis.

CONCLUSION

Heparin-free on-line predilutional HDF is a safe and effective technique for chronic hemodialysis patients with increased bleeding risk. The use of an automatic substitution volume that avoids filters hemoconcentration and of a blood flow above 250 mL/min strongly contribute to the observed performance. Further studies are, however, intended to confirm these results.

Hemodialysis access thrombosis

For the over 400,000 patients in the United States dependent on hemodialysis, arteriovenous (AV) access thrombosis may lead to missed dialysis sessions, inpatient admissions and the need for placement of temporary dialysis catheters. It is also the leading cause of permanent access loss. Percutaneous declotting is generally preferred over surgical thrombectomy. Various percutaneous approaches can be employed including the lyse-and-wait technique, thromboaspiration, pulse spray aided pharmacomechanical thrombolysis, and use of mechanical thrombectomy device.

Upper-extremity Deep Vein Thrombosis Complicating Apheresis in a Healthy Donor

Venous thrombus was recognized in the upper extremity of a 53-year-old man after blood donation. The patient presented with a 15-day history of swelling in the left upper-extremity that started 6 hours after apheresis. Contrast-enhanced computed tomography revealed clots in the deep veins of the left arm and the peripheral pulmonary artery. Blood donation had proceeded smoothly, and the patient had no thrombotic predisposition, except for a smoking habit. The thrombus resolved following anticoagulant therapy, and the patient' s clinical course was uncomplicated. Despite a thorough investigation, the cause of this thrombus remains unknown.

Differences in the adsorption of nafamostat mesilate between polyester-polymer alloy and polysulfone membranes

We previously experienced severe clot formation in a polyester-polymer alloy (PEPA) dialyzer and hemodialysis (HD) circuit with nafamostat mesilate (NM) as an anticoagulant. The possibility of NM adsorption to the PEPA membrane was taken into consideration, but there was not enough information. In the present study, we evaluated differences in the adsorption of NM between a PEPA membrane (FDX-120 GW, Nikkiso, Tokyo, Japan) and two different polysulfone membranes (FX-140, Fresenius Medical Care, Tokyo, Japan; NV-15U, Toray Medical, Tokyo, Japan). We calculated the NM concentration by measuring absorbance at 241 nm using a spectrometer. NM adsorption was evaluated in three ways. First, we evaluated NM adsorption to hollow fibers. Then, we passed an NM solution through dialyzers and evaluated its adsorption in a single-pass examination. Finally, we circulated an NM solution in an HD circuit using a blood pump and evaluated NM adsorption. In all the experiments, NM adsorption to the PEPA membrane was greater than that to the polysulfone membranes examined. In the blood pump experiment, the estimated adsorption quantities of NM to the PEPA membrane and the FX-140 and NV-15U polysulfone membranes were 12.0 ± 0.1, 1.0 ± 0.1, and 4.1 ± 0.4 mg/m², respectively. NM adsorption was confirmed, especially in the early phase, and the PEPA membrane adsorbed greater amounts of NM than the polysulfone membranes. We should pay attention to the choice of dialyzer as well as the appropriate dose of NM administration during the preparation of HD circuits.

Biocompatibility assessment of haemodialysis membrane materials by proteomic investigations

We examine and compare the protein adsorption capacity and coagulation profiles of different haemodialysis membrane biomaterials.

[Predilution online hemodiafiltration: which dose of anticoagulation?]

INTRODUCTION

Patients in end stage renal disease on hemodialysis are in higher risk of bleeding related to the anticoagulation used during a session, so only the lowest effective dose of anticoagulation must be used. The aim of this study was to evaluate the efficacy of predilution in hemodiafiltration with reduced dose of anticoagulation compared to hemodialysis in preventing coagulation of circuits.

PATIENTS AND METHODS

This study was conducted in stable hemodialysis patients without high bleeding risk. All patients were treated by two different treatments: (A) conventional hemodialysis, (B) predilution hemodiafiltration with the half dose of anticoagulation used during treatment (A). Other confounding parameters were kept constant during the study. The primary endpoint was the incidence of major thrombotic events judged on a subjective visual score.

RESULTS

Twenty-one patients were included (105 sessions for each treatment). Major incidents are occurring more frequently in predilution hemodiafiltration with reduced dose of anticoagulation (P=0.03). The premature discontinuation of sessions was more frequent in predilution hemodiafiltration, this difference was not significant (P=0.07). Duration of sessions was significantly shorter in predilution hemodiafiltration (P=0.03). The higher frequency of thrombotic events in predilution hemodiafiltration has no effect on net ultrafiltration volume achieved in both treatments.

CONCLUSION

Predilution hemodiafiltration with a lower dose of anticoagulation did not prevent major clotting of extracorporeal circuit manner at least equivalent to a reference method.

Heparin-grafted dialysis membrane allows minimal systemic anticoagulation in regular hemodialysis patients: a prospective proof-of-concept study

This prospective, multicenter, proof-of-concept study aimed to evaluate the possibility to reduce the ordinary heparin dose and the systemic anti-Xa activity during hemodialysis (HD) sessions using a new heparin-grafted HD membrane. In 45 stable HD patients, the use of a heparin-grafted membrane with the ordinary heparin dose was followed by a stepwise weekly reduction of dose. Reduction was stopped when early signs of clotting (venous pressure, quality of rinse-back) occurred during two out of three weekly HD sessions. Heparin dose was decreased for 67% of patients resulting in the lowering of these patients' anti-Xa activity by 50%. Dose reductions were achieved with both types of heparin (low-molecular-weight heparin: 64 ± 14 to 35 ± 12 IU/kg, P < 0.0001; unfractionated heparin: 82 ± 18 to 46 ± 13 IU/kg, P < 0.0001) resulting in a decrease of anti-Xa activity at dialysis session end (low-molecular-weight heparin: 0.51 ± 0.25 to 0.25 ± 0.11 IU/mL, P < 0.0001; unfractionated heparin: 0.28 ± 0.23 to 0.13 ± 0.07 IU/mL, P < 0.0001). Failure to further decrease heparin dose was related to signs of clotting in blood lines (57% of sessions), in dialyzer (9%), or both (34%). Significant reduction of heparin dose and anti-Xa activity at the end of HD sessions was possible in stable HD patients using heparin-grafted membrane. HD patients who require low anti-Xa activity at the end of HD sessions might benefit from a heparin-grafted membrane to reduce bleeding risk and other heparin adverse events.

Citrate anticoagulation using ACD solution A during long-term haemodialysis

AIM

Haemodialysis with regional citrate anticoagulation in patients with contraindications for heparin is increasingly performed in the USA and Europe. Most published protocols use trisodium citrate, which is not readily available nor is it licensed in Australia. We established a protocol for citrate-anticoagulation in haemodialysis using acid citrate dextrose solution A (ACDA), which is approved for apheresis procedures in Australia. The aim of the present study was to assess the safety and efficacy of this protocol for routine use in haemodialysis patients.

METHODS

Systemic and post-filter blood ionized calcium, serum sodium and bicarbonate and dialyzer clotting score were analyzed prospectively in 14 patients undergoing 150 consecutive haemodialysis treatments with citrate anticoagulation using calcium-free dialysate. A simple algorithm allowed the attending nurse to adjust citrate infusion (to maintain post-filter ionized calcium at 0.2-0.3 mmol/L) and i.v. calcium substitution. Scheduled dialysis time was 4 h, and point-of-care monitoring of blood ionized calcium during dialysis was done at 0, 15, 60, 120 and 240 min.

RESULTS

ACDA infusion rates of 300 mL/h were used in the first 52 treatments, but resulted in high dialyzer clotting score and 6% of treatments were discontinued due to complete clotting. Thereafter, ACDA infusion rate was increased to 350 mL/h, with all 98 subsequent treatments completed successfully. Ionized calcium levels were stable during all procedures with post-dialysis serum sodium averaging 135 ± 3 mmol/L and bicarbonate 23.8 ± 2 mmol/L.

CONCLUSION

Routine use of citrate anticoagulation in the setting of a long-term haemodialysis unit is safe and efficient. Point-of-care measurements of ionized calcium levels are critical to safely and successfully perform citrate anticoagulation.

Liver transplantation avoided in patients with fulminant hepatic failure who received albumin dialysis with the molecular adsorbent recirculating system while on the waiting list: impact of the duration of therapy

Eighteen patients with fulminant hepatic failure due to various medical causes were listed for emergency liver transplantation and treated with extracorporeal albumin dialysis sessions using the molecular adsorbent recirculating system (MARS) at our center over a 74-month period. Due to improvement of liver function, transplantation could be avoided in 9 patients (50%, 95% confidence interval 29% to 71%) who fully recovered afterwards. This improvement rate was higher than the rate of improvement in the French cohort of fulminant hepatic failure patients with similar etiologies (19.3%, 95% confidence interval 14.9% to 24.6%, P = 0.002). In our 18 patients, there were no statistically significant differences in any baseline characteristics or in the time with liver failure meeting transplant criteria between the patients who improved while waiting and those who did not. However, the patients who improved received a greater number of sessions and a longer total duration of MARS therapy (all P < 0.001). In the whole study population, a MARS therapy duration > or =15 h was significantly associated with improvement of liver function without transplantation (adjusted adds ratio [OR] 65.76, 2.48-1743.11, P = 0.01). Tolerance of therapy was acceptable. These results suggest that MARS therapy could contribute to native liver recovery and is safe in patients on the waiting list for fulminant hepatic failure. A minimum duration of therapy (> or =15 h) could be necessary to expect significant liver function improvement.