Comparison of Citrate and Heparin Anticoagulation During Postdilution Hemodiafiltration (CITRA-HDF)

May 27, 2026 updated by: Milena Andonova, University Medical Centre Ljubljana

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

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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Estimated)

20

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Slovenia
      • Ljubljana, Slovenia, 1000
        • University Medical Centre Ljubljana
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Citrate anticoagulation
Participants will undergo postdilution hemodiafiltration using regional citrate anticoagulation with 8% trisodium citrate infusion and calcium substitution according to ionized calcium measurements
Drug: Regional citrate anticoagulation
Regional citrate anticoagulation using 8% trisodium citrate infusion during postdilution hemodiafiltration with calcium substitution adjusted according to ionized calcium levels.
Active Comparator: Heparin anticoagulation
Participants will undergo postdilution hemodiafiltration using standard unfractionated heparin anticoagulation according to routine clinical protocol.
Drug: Unfractionated heparin
Standard unfractionated heparin anticoagulation administered according to routine clinical protocol during postdilution hemodiafiltration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Before hemodiafiltration, after 15 minutes of treatment, and immediately before the end of the procedure.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Before, after 30 minutes and at the end of the procedure hemodiafiltration procedure.
instantaneous urea clearance after 30 minutes
Time Frame: after 30 minutes of dialysis
instantaneous urea clearance after 30 minutes
after 30 minutes of dialysis
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
P-cresyl sulfat removal before, during and to the end of procedure
Ionized calcium kinetics
Time Frame: During the 4-hour hemodiafiltration procedure
During citrate anticoagulation procedure
During the 4-hour hemodiafiltration procedure
Extracorporeal circuit clotting score
Time Frame: At the end of hemodiafiltration procedure.
At the end of hemodiafiltration procedure.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University Medical Centre Ljubljana

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 5, 2026

Primary Completion (Estimated)

December 15, 2026

Study Completion (Estimated)

April 1, 2027

Study Registration Dates

First Submitted

May 16, 2026

First Submitted That Met QC Criteria

May 27, 2026

First Posted (Actual)

June 1, 2026

Study Record Updates

Last Update Posted (Actual)

June 1, 2026

Last Update Submitted That Met QC Criteria

May 27, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • BIOCOMP-HDF
  • 0120-610/2025-2711-5 (Registry Identifier: Republic of Slovenia National Medical Ethics Committee)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be publicly available due to privacy and institutional data protection regulations.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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