Heparin albumin priming in a clinical setting for hemodialysis patients at risk for bleeding

Avoiding Systemic Heparinization During Hemodialysis: How the Dialysis Setup Might Help

Heparin is the most widely used anticoagulant for maintaining patency of the extracorporeal blood circuit during intermittent hemodialysis. Inadvertently, this leads to systemic heparinization of the patient. Repeated intermittent heparinization during hemodialysis has been associated with increased bleeding risks and metabolic and immunologic effects. Alternative strategies for minimizing systemic anticoagulation encompass dilution methods, regional citrate anticoagulation, priming of the extracorporeal circuit, and modifications to dialyzer membranes and dialysate composition. The effectiveness of these alternatives in maintaining patency of the extracorporeal circuit varies substantially. Although most studies have focused on particular changes in the hemodialysis setup, several combined interventions for adapting the hemodialysis setup are now being studied. This narrative review aims to present an overview of the current landscape of hemodialysis setup strategies aimed at limiting or avoiding systemic anticoagulation during treatment. Additionally, this review intends to shed light on the underlying pathophysiological mechanisms that contribute to variations observed in reported outcomes.

Heparin locks with low and high concentration in haemodialysis patients: A systematic review and meta-analysis

AIM

There is no evidence-based consensus on the optimal concentration for heparin locks; several randomized controlled trials (RCTs) have evaluated the concentration of heparin locks, yet the results remain inconsistent. We aimed to assess heparin locks with low and high concentration in haemodialysis patients.

METHODS

We performed a systematic review and meta-analysis of RCTs focusing on the concentration in heparin locks. Studies were identified by searching PUBMED, EMBASE, Science Direct, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure (CNKI) and Wanfang databases (from inception to 15 March 2020). Summary risk ratios or mean differences with 95% confidence interval were calculated.

RESULTS

A total of 370 patients with four RCTs were included. Heparin locks with 1000 U/ml could significantly reduce the activated partial thromboplastin time (APTT) compared with 5000 U/ml. No significant differences were seen in the occurrence of catheter-related thrombosis, the length of catheter stay, the rates of bleeding and catheter occlusions between the two groups.

CONCLUSIONS

Lower concentrations in heparin lock are optimal for shortening APTT in haemodialysis patients; further studies are needed to elucidate the role of heparin concentration in the lock practice.

Anticoagulation in hemodialysis: A narrative review

Systemic anticoagulation in maintenance hemodialysis (HD) has historically been considered necessary to maintain the extracorporeal circuit (ECC) and preserve dialysis efficiency. Unfractionated heparin (UFH) is the most commonly used anticoagulant due to low cost and staff familiarity. Despite widespread use, there is little standardization of heparin dosing protocols in the United States. Although the complication rates with UFH are low for the general population, certain contraindications have led to exploration in alternative anticoagulants in patients with end-stage kidney disease (ESKD). Here we review the current evidence regarding heparin dosing protocols, complications associated with heparin use, and discuss alternatives to UFH including anticoagulant-free routine HD.

Evaluation of Different Dialyzers and the Impact of Predialysis Albumin Priming in Intermittent Hemodialysis With Reduced Anticoagulation

Introduction

Systemic anticoagulation is widely used in routine clinical hemodialysis, but can be contraindicated in specific settings. Anticoagulant-free treatment regimens are prone to failure even in chronic intermittent hemodialysis. We quantified fiber blocking in settings of reduced anticoagulation to assess performance of different dialyzers and the potential benefit of albumin priming.

Methods

This crossover study included 10 patients performing 4 hours of hemodialysis at midweek in 7 different settings: that is, using Solacea 19H and FX800, both with regular and half dose of anticoagulation, Evodial 1.3 without systemic anticoagulation, and FX800 (half dose) and Evodial (no anticoagulation) when primed with a human albumin solution. Dialyzer fiber blocking was visualized in the dialyzer outlet potting using a 3-dimensional computed tomography (CT) scanning technique on micrometer resolution.

Results

No sessions had to be prematurely interrupted because of circuit clotting. The relative number of open fibers post dialysis was not influenced by the reduction of anticoagulation in the Solacea making this dialyzer superior in fiber patency in this setting above both the FX800 with reduced anticoagulation and the Evodial with no anticoagulation. Furthermore, no differences in relative number of open fibers were found in the FX800 and Evodial dialyzers with versus without albumin priming.

Conclusion

In situations in which reduced anticoagulation is indicated, the asymmetric triacetate ATA Solacea dialyzer outperforms a dialyzer with a conventional polysulfone membrane (FX800) or with the heparin-coated polyacrylonitrile membrane (Evodial). The use of human albumin to prime the dialysis circuit did not improve dialyzer patency.

An evaluation of four modes of low-dose anticoagulation during intermittent haemodialysis

Introduction

Intensive care participants that need dialysis frequently suffer from increased risk of bleeding. Standard intermittent haemodialysis (SHD) includes anticoagulation to avoid clotting of the dialysis system. The aim of this study was to clarify which of four different low-dose anticoagulant modes was preferable in reducing the exposure to i.v. unfractionated heparin (heparin) and maintaining patency of the dialysis circuit.

Methods

Twenty-three patients on SHD were included to perform haemodialysis with four modes of low-dose anticoagulation. For comparative analyses, patients served as their own control. Haemodialysis with a single bolus of tinzaparin at the start was compared to haemodialysis initiated without i.v. heparin but priming with (1) heparin in saline (H), (2) heparin and albumin in saline (HA), (3) heparin and albumin in combination with a citrate-containing dialysate (HAC), (4) saline and usinga heparin-coated filters (Evodial®). The priming fluid was discarded before dialysis started. Blood samples were collected at 0, 30 and 180 min during haemodialysis. Smaller bolus doses of heparin (500 Units/dose) were allowed during the modes to avoid interruption by clotting.

Findings

The mean activated partial thromboplastin (APTT) time as well as the doses of anticoagulation administered was highest with SHD and least with HAC and Evodial®. Mode H versus SHD had the highest rate of prematurely interrupted dialyses (33%, p = 0.008). The urea reduction rate was less with Evodial® vs. SHD (p < 0.01). One hypersensitivity reaction occurred with Evodial®. Changes in blood cell concentrations and triglycerides differed between the modes.

Discussion

If intermittent haemodialysis is necessary in patients at risk of bleeding, anticoagulation using HAC and Evodial® appeared most preferable with least administration of heparin, lowest APTT increase and lowest risk for prematurely clotted dialyzers in contrast to the least plausible H mode.

Electronic supplementary material

The online version of this article (10.1007/s00228-017-2389-x) contains supplementary material, which is available to authorized users.