Anticoagulation for people receiving long-term haemodialysis

BACKGROUND

Haemodialysis (HD) requires safe and effective anticoagulation to prevent clot formation within the extracorporeal circuit during dialysis treatments to enable adequate dialysis and minimise adverse events, including major bleeding. Low molecular weight heparin (LMWH) may provide a more predictable dose, reliable anticoagulant effects and be simpler to administer than unfractionated heparin (UFH) for HD anticoagulation, but may accumulate in the kidneys and lead to bleeding.

OBJECTIVES

To assess the efficacy and safety of anticoagulation strategies (including both heparin and non-heparin drugs) for long-term HD in people with kidney failure. Any intervention preventing clotting within the extracorporeal circuit without establishing anticoagulation within the patient, such as regional citrate, citrate enriched dialysate, heparin-coated dialysers, pre-dilution haemodiafiltration (HDF), and saline flushes were also included.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to November 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-randomised controlled studies (quasi-RCTs) evaluating anticoagulant agents administered during HD treatment in adults and children with kidney failure.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias using the Cochrane tool and extracted data. Treatment effects were estimated using random effects meta-analysis and expressed as relative risk (RR) or mean difference (MD) with 95% confidence intervals (CI). Evidence certainty was assessed using the Grading of Recommendation, Assessment, Development and Evaluation approach (GRADE).

MAIN RESULTS

We included 113 studies randomising 4535 participants. The risk of bias in each study was adjudicated as high or unclear for most risk domains. Compared to UFH, LMWH had uncertain effects on extracorporeal circuit thrombosis (3 studies, 91 participants: RR 1.58, 95% CI 0.46 to 5.42; I2 = 8%; low certainty evidence), while major bleeding and minor bleeding were not adequately reported. Regional citrate anticoagulation may lower the risk of minor bleeding compared to UFH (2 studies, 82 participants: RR 0.34, 95% CI 0.14 to 0.85; I2 = 0%; low certainty evidence). No studies reported data comparing regional citrate to UFH on risks of extracorporeal circuit thrombosis and major bleeding. The effects of very LMWH, danaparoid, prostacyclin, direct thrombin inhibitors, factor XI inhibitors or heparin-grafted membranes were uncertain due to insufficient data. The effects of different LMWH, different doses of LMWH, and the administration of LMWH anticoagulants using inlet versus outlet bloodline or bolus versus infusion were uncertain. Evidence to compare citrate to another citrate or control was scant. The effects of UFH compared to no anticoagulant therapy or different doses of UFH were uncertain. Death, dialysis vascular access outcomes, blood transfusions, measures of anticoagulation effect, and costs of interventions were rarely reported. No studies evaluated the effects of treatment on non-fatal myocardial infarction, non-fatal stroke and hospital admissions. Adverse events were inconsistently and rarely reported.

AUTHORS' CONCLUSIONS

Anticoagulant strategies, including UFH and LMWH, have uncertain comparative risks on extracorporeal circuit thrombosis, while major bleeding and minor bleeding were not adequately reported. Regional citrate may decrease minor bleeding, but the effects on major bleeding and extracorporeal circuit thrombosis were not reported. Evidence supporting clinical decision-making for different forms of anticoagulant strategies for HD is of low and very low certainty, as available studies have not been designed to measure treatment effects on important clinical outcomes.

A review of 122 published outcomes of danaparoid anticoagulation for intermittent haemodialysis

One hundred and twenty-two case reports of treatment outcomes of danaparoid use for intermittent haemodialysis (HD) in severely ill patients with heparin intolerance (including 97 HIT patients) have been analysed. HD sessions of 4 - 6 hours were successfully conducted daily to 3 times/week for periods of up to 4 years (median 7 sessions/patient (range 1 - >650). In these patients danaparoid use was relatively safe (4 unprovoked non-fatal major bleeds) and efficacious in protecting the circuit (95% no clotting problem) or patient (6 thromboses: 4 fatal or leading to danaparoid discontinuation). HIT diagnosis was improved if recurrent platelet count reduction with each HD and circuit/AV graft clotting were included. Alternative reasons for and very low nadirs of the platelet count undermined the usefulness of the 4 T pre-test HIT predictability scores, but a positive functional serological test confirmed HIT in most patients. Deaths (15.6%) and thrombosis only occurred in HIT cases. Possible reasons are discussed. Replacing the standard intermittent pre-HD dose regimen with the therapeutic infusion regimen to provide continuous daily systemic antithrombotic protection, should further improve efficacy.

CONCLUSION

Danaparoid appears to be a useful alternative antithrombotic for patients with heparin intolerance and renal failure requiring haemodialysis.

[Thrombocytopathy and blood complications in uremia]

Bleeding diathesis and thrombotic tendencies are characteristic findings in patients with end-stage renal disease. The pathogenesis of uremic bleeding tendency is related to multiple dysfunctions of the platelets. The platelet numbers may be reduced slightly, while platelet turnover is increased. The reduced adhesion of platelets to the vascular subendothelial wall is due to reduction of GPIb and altered conformational changes of GPIIb/IIIa receptors. Alterations of platelet adhesion and aggregation are caused by uremic toxins, increased platelet production of NO, PGI(2), calcium and cAMP as well as renal anemia. Correction of uremic bleeding is caused by treatment of renal anemia with recombinant human erythropoietin or darbepoetin alpha, adequate dialysis, desmopressin, cryoprecipitate, tranexamic acid, or conjugated estrogens. Thrombotic complications in uremia are caused by increased platelet aggregation and hypercoagulability. Erythrocyte-platelet-aggregates, leukocyte-platelet-aggregates and platelet microparticles are found in higher percentage in uremic patients as compared to healthy individuals. The increased expression of platelet phosphatidylserine initiates phagocytosis and coagulation. Therapy with antiplatelet drugs does not reduce vascular access thrombosis but increases bleeding complications in endstage renal disease patients. Heparin-induced thrombocytopenia (HIT type II) may develop in 0-12 % of hemodialysis patients. HIT antibody positive uremic patients mostly develop only mild thrombocytopenia and only very few thrombotic complications. Substitution of heparin by hirudin, danaparoid or regional citrate anticoagulation should be decided based on each single case.

Pharmacokinetic studies of dalteparin (Fragmin), enoxaparin (Clexane), and danaparoid sodium (Orgaran) in stable chronic hemodialysis patients

BACKGROUND

Low molecular weight heparins (LMWHs) and danaparoid are an alternative to unfractionated heparin (UH) for anticoagulation during hemodialysis. Few data are available concerning their duration of action and whether drug accumulation occurs with continued use. We performed a prospective randomized study of the pharmacokinetics of dalteparin and enoxaparin plus danaparoid in 21 hemodialysis patients.

METHODS

Patients were randomly assigned to administration of enoxaparin, 40 mg; dalteparin, 2,500 U; or danaparoid, 34 U/kg, for 4 weeks. Antifactor Xa levels were measured at the end of weeks 1 and 4 immediately before the injection and at prescribed intervals up to 48 hours postinjection.

RESULTS

No bleeding or thrombotic episodes occurred during the study. Mean antifactor Xa activities 4 hours postinjection were 0.2 +/- 0.035 (SEM), 0.38 +/- 0.028, and 0.54 +/- 0.051 U/mL week 1 and 0.26 +/- 0.038, 0.40 +/- 0.055, and 0.64 +/- 0.050 U/mL week 4 for dalteparin, enoxaparin, and danaparoid, respectively. Both weeks 1 and 4, antifactor Xa activity 3 hours postdose was significantly greater for danaparoid sodium compared with enoxaparin and dalteparin. There were no significant differences between antifactor Xa activity week 4 versus week 1 for enoxaparin and dalteparin; however, danaparoid sodium levels during dialysis were significantly greater after 4 weeks of treatment (P = 0.0328, 1 hour; P = 0.003, 2 hours; P = 0.0128, 3 and 4 hours).

CONCLUSION

Dalteparin and enoxaparin provide adequate anticoagulation for hemodialysis using single bolus injections at relatively low doses. Danaparoid sodium at the current recommended dosage resulted in greater anticoagulation than enoxaparin or dalteparin and may have an

Use of a low-molecular-weight heparinoid (danaparoid sodium) for continuous renal replacement therapy in intensive care patients

The purpose of this study was to evaluate the efficacy and safety of danaparoid in the treatment of critically ill patients with acute renal failure and suspected heparin-induced thrombocytopenia (HIT) needing renal replacement therapy (RRT). We conducted a retrospective analysis of 13 consecutive intensive care patients with acute renal failure and suspected HIT who were treated with danaparoid for at least 3 days during RRT. In eight patients, continuous venovenous hemofiltration was performed. The mean infusion rate of danaparoid was 140 +/- 86 U/hour. Filter exchange was necessary every 37.5 hours. In five patients, continuous venovenous hemodialysis was used. A bolus injection of 750 U danaparoid was followed by a mean infusion rate of 138 +/- 122 U/hour. Filters were exchanged every 24 hours. In 7 of 13 patients, even a low mean infusion rate of 88 +/- 35 U/hour was efficient. Mean anti-Xa (aXa) levels were approximately 0.4 +/- 0.2 aXa U/mL. Persistent thrombocytopenia despite discontinuation of heparin treatment was observed in 9 of 13 patients, owing to disseminated intravascular coagulation (DIC). HIT was confirmed by an increase in platelet count and positive heparin-induced antibodies in 2 of 13 patients. No thromboembolic complications occurred, but major bleeding was observed in 6 of 13 patients, which could be explained by consumption of coagulation factors and platelets due to DIC in 5 of 6 patients. Nine of 13 patients died of multiorgan failure or sepsis, or both. In none of these patients was the fatal outcome related to danaparoid treatment. In critically ill patients with renal impairment and suspected HIT, a bolus injection of 750 U danaparoid followed by a mean infusion rate of 50 to 150 U/hour appears to be a safe and efficient treatment option when alternative anticoagulation is necessary.

Danaparoid in the prevention of thromboembolic complications

OBJECTIVE

To review the therapies used to prevent postoperative thromboembolic complications with a focus on the role of danaparoid, a new low-molecular-weight glycosaminoglycan.

DATA SOURCES

A MEDLINE search was performed to identify pertinent English-language literature including studies, abstracts, and review articles. Key search terms included danaparoid, heparinoid, lomoparin, heparin, prophylaxis, thrombosis, embolism, thromboembolism, and thromboembolic and postoperative complications. The manufacturer of danaparoid was contracted for additional information related to this compound.

STUDY SELECTION AND DATA EXTRACTION

All identified articles were reviewed for possible inclusion in this review. Comparisons primarily focused on data obtained from prospective, randomized, controlled, blind clinical trials. Another important consideration was the use of venography to determine the presence of deep venous thrombosis.

DATA SYNTHESIS

Various therapies are available for the prevention of postoperative thromboembolic complications. Effective pharmacologic treatments currently available include adjusted-dose heparin, warfarin, aspirin, dextran, and low-molecular-weight heparins (LMWHs). Until recently, warfarin was considered the drug of choice for thromboprophylaxis in high-risk patients, including patients undergoing orthopedic surgical procedures. Because of their comparable efficacy and greater ease of use, LMWHs are gaining favor over warfarin in this patient population. In well-designed clinical trials involving patients undergoing elective total hip replacement or fractured hip surgery, danaparoid has demonstrated greater efficacy than other active treatments, including warfarin, dextran, aspirin, and heparin plus dihydroergotamine. While studies comparing danaparoid with LMWHs have not yet been published, danaparoid may be more useful in patients with heparin-associated thrombocytopenia.

CONCLUSIONS

Danaparoid is an antithrombotic agent with characteristics that distinguish it from heparin and LMWHs. Based on the efficacy and safety data reviewed, danaparoid should be considered one of the drugs of choice for the prevention of thromboembolic complications in patients undergoing orthopedic hip procedures and the drug of choice for the management of any patient with heparin-induced thrombocytopenia who requires anticoagulant therapy.

Reduced lipid concentrations during four years of dialysis with low molecular weight heparin

Heparin is used as standard anticoagulant in the extracorporeal circuit of hemodialysis. Widespread use of this drug revealed several potentially adverse effects, such as release of lipoprotein lipase and hepatic lipase from the endothelial surface. Recently it was found that anticoagulatory potency and provocation of adverse effects are linked to different subfractions of heparin. A heparin subfraction of 4000 to 6000 Daltons rather specifically inhibits factor Xa and therefore has a very high antithrombotic potency. Its effects on release of lipases are minor. During a four year period five patients on maintenance hemodialysis were treated with this low molecular weight heparin (LMWH) subfraction. Additionally, another five patients successively received standard heparin, LMWH and again standard heparin. At all circumstances during treatment with LMWH there was a significant (0.001 less than P less than 0.05) reduction both of cholesterol and triglyceride blood concentrations. LMWH is efficient in avoiding clotting in extracorporeal circuit during hemodialysis in doses of 17 to 95 U/kg (initial dose) and 7 to 20 U/kg/hr (continuous dose).