After providing informed consent, patients will be randomized to either the intervention treatment ("EvoCit procedure") or the control treatment ("EvoHep procedure").

After randomization, each study arm consists of four weeks of 3x4 hours hemodialysis treatments according to the allocated protocol. After the last dialysis treatment of the fourth treatment week and after a long interdialytic interval, patients will crossover to the alternative hemodialysis procedure. After crossover, the study will be completed with, again, four weeks of 3x4 hours hemodialysis treatments according to the allocated protocol.

Inclusion Criteria:

• Patients treated with hemodialysis or hemodiafiltration since at least three months.
• Hemodialysis or hemodiafiltration prescription of 3 x 4 hours weekly.
• ≥ 18 years of age.
• Patients able and agree to provide signed informed consent.

Exclusion Criteria:

• Contraindication to heparin defined as known heparin-induced thrombopenia or active bleeding risk with contra-indication for systemic anticoagulation, categorized as defined by Swartz and Port1.

• Planned surgery during study period, including scheduled living-donor kidney transplantation during study period.

• Hypercoagulable state defined as known malignancy, known APC resistance/FV Leiden, known prothrombin gene mutation, known protein C or protein S deficiency, known antithrombin deficiency.

• Mean Qb of <300ml/min during one of the last 3 dialysis sessions before inclusion.

• 1 or more results of spKt/Vurea < 1,35 during the last three months prior to study inclusion.

• Need for 2 or more supplementary dialysis sessions on top of the regular 3x4 hours weekly hemodialysis regimen during the last month before inclusion.

• Vascular access dysfunction defined as

  1. use of urokinase the 2 months before study inclusion, including to restore catheter permeability.
  2. non-tunneled hemodialysis catheter use.
  3. known AV access outflow tract stenosis.
  4. planned vascular access intervention.
  5. planned vascular access conversion.

• Known allergy against heparin grafted AN69STmembranes.

• Use of ACE-inhibitor

• Use of vitamin K antagonist

• Use of novel oral anticoagulant therapy.

• Any medical condition, which puts the patient at risk of premature study termination in the opinion of the investigator.

• Planned conversion of dialysis modality during study period or planned absence/leave (including pregnancy or planned pregnancy).

• Symptomatic hypocalcemia.

• Hb < 8g/dl at screening.

• Hct > 45% at screening.

• Perdialytic total parenteral nutrition therapy