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NCT Number: NCT07618858

Comparison of Citrate and Heparin Anticoagulation During Postdilution Hemodiafiltration

This randomized crossover clinical trial will compare regional citrate anticoagulation (RCA) and standard heparin anticoagulation (HA) during postdilution hemodiafiltration (HDF) in chronic dialysis patients with end-stage kidney disease.

The primary aim of the study is to evaluate biocompatibility during HDF by measuring markers of complement activation (C3a), platelet activation (PF4), and coagulation activation (thrombin-antithrombin complex, TAT).

Secondary aims include comparison of solute removal efficiency, including beta-2 microglobulin, phosphate, and urea removal, as well as assessment of citrate, calcium, and magnesium kinetics during citrate anticoagulation.

Twenty adult chronic dialysis patients will undergo two study HDF procedures in randomized order: one procedure using heparin anticoagulation and one procedure using regional citrate anticoagulation with a one-week interval between procedures.

The study aims to improve understanding of the effects of anticoagulation methods on hemodiafiltration biocompatibility and dialysis efficiency and may contribute to optimization of citrate anticoagulation protocols in chronic hemodiafiltration patients.

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Key information

Conditions

End-stage Kidney Disease Chronic Disease Chronic Hemodialysis Disease Attributes Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Hemodiafiltration Kidney Diseases Kidney Failure, Chronic Male Urogenital Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Renal Failure Renal Insufficiency Renal Insufficiency, Chronic Urogenital Diseases Urologic Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

About this study

Hemodiafiltration (HDF) is an advanced renal replacement therapy combining diffusion and convection, allowing improved removal of middle and larger molecular weight solutes compared with standard hemodialysis. During extracorporeal circulation, blood contact with artificial membranes and tubing activates complement, platelets, leukocytes, and coagulation pathways, requiring anticoagulation during the procedure.

Unfractionated heparin is routinely used for anticoagulation during HDF. Regional citrate anticoagulation (RCA) is mainly used in patients at increased bleeding risk. Previous studies in hemodialysis have suggested that citrate anticoagulation may improve biocompatibility because many blood-material interactions are calcium- and magnesium-dependent. However, biocompatibility during HDF using citrate versus heparin anticoagulation has not been systematically investigated.

This prospective randomized crossover clinical trial will include 20 adult patients with end-stage kidney disease receiving maintenance postdilution hemodiafiltration three times weekly. Patients will be randomized to one of two anticoagulation sequences: heparin-citrate or citrate-heparin. Each participant will undergo two study HDF procedures separated by a one-week interval.

During heparin anticoagulation, unfractionated heparin will be administered according to body weight using standard clinical protocols. During citrate anticoagulation, 8% trisodium citrate infusion and calcium-free dialysate will be used, with continuous calcium chloride substitution adjusted according to ionized calcium levels.

Biocompatibility markers including complement activation marker C3a, platelet factor 4 (PF4), thrombin-antithrombin complex (TAT), blood cell counts, and coagulation parameters will be assessed before HDF, after 15 minutes, and at the end of the procedure.

Dialysis efficiency will be evaluated by measurement of reduction ratios and total removal of beta-2 microglobulin, phosphate, and urea using partial dialysate collection methodology.

Additional secondary outcomes include assessment of citrate, calcium, and magnesium kinetics during RCA-HDF, visual clotting score evaluation of the extracorporeal circuit, and optimization of citrate anticoagulation protocols during postdilution HDF.

The study may contribute to improved understanding of anticoagulation-related biocompatibility during HDF and support wider evidence-based use of regional citrate anticoagulation in chronic dialysis patients.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged 18 years or older
  • End-stage kidney disease requiring maintenance postdilution hemodiafiltration
  • Stable chronic hemodialysis treatment three times weekly
  • Functional arteriovenous fistula

Exclusion criteria

  • Therapeutic anticoagulation therapy
  • Dual antiplatelet therapy
  • Significant coagulopathy
  • Active bleeding
  • Acute kidney injury

Treatment and study plan

Regional citrate anticoagulation

Drug

Regional citrate anticoagulation using 8% trisodium citrate infusion during postdilution hemodiafiltration with calcium substitution adjusted according to ionized calcium levels.

Unfractionated heparin

Drug

Standard unfractionated heparin anticoagulation administered according to routine clinical protocol during postdilution hemodiafiltration.

Primary outcomes

  1. Biocompatibility markers (C3a, PF4, TAT)

    Time frame: Before hemodiafiltration, after 15 minutes of treatment, and immediately before the end of the procedure.

    Comparison of complement activation marker C3a, platelet factor 4 (PF4), and thrombin-antithrombin complex (TAT) concentrations between citrate and heparin anticoagulation during postdilution hemodiafiltration.

Secondary outcomes

  1. Beta-2 microglobulin removal

    Time frame: Before, after 30 minutes and at the end of the procedure hemodiafiltration procedure.

    Reduction ratio and total removal of beta-2 microglobulin during hemodiafiltration.

  2. instantaneous urea clearance after 30 minutes

    Time frame: after 30 minutes of dialysis

    instantaneous urea clearance after 30 minutes

  3. p-cresyl sulfat removal

    Time frame: P-cresyl sulfat removal before, during and to the end of procedure

    P-cresyl sulfat removal before, after 30 minutes and at the end of the procedure

  4. Ionized calcium kinetics

    Time frame: During the 4-hour hemodiafiltration procedure

    During citrate anticoagulation procedure

  5. Extracorporeal circuit clotting score

    Time frame: At the end of hemodiafiltration procedure.

Study contacts

Contact information is provided by the study sponsor or research team.

Milena MD Andonova

CONTACT

[email protected]

+38615228123

Sponsors and collaborators

Lead sponsor

University Medical Centre Ljubljana

Other

Registry information

Official study title

Efficiency and Biocompatibility of Postdilution Hemodiafiltration Using Different Anticoagulation Methods: A Randomized Crossover Clinical Trial

Acronym: CITRA-HDF

Important dates

Study start
2026
Primary completion
2026
Study completion
2027
First posted
Jun 1, 2026
Registry last updated
Jun 1, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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