Avoidance of Systemic Anticoagulation During Hemodialysis with Hydrolink Membrane and Citrate-Dialysate: A Single-Center Observational Study

Background: In hemodialysis (HD), avoiding anticoagulation is preferable in patients at increased risk of bleeding but may be challenging due to the risk of circuit clotting. The use of NV-U® (Hydrolink™) membrane, or citrate-based dialysate, has been shown to reduce the risk of circuit thrombosis. However, the combined use of both strategies has not yet been evaluated. This study aimed to assess the feasibility and efficacy of this combination for conducting anticoagulation - free HD sessions in patients at bleeding risk, and to identify risk factors associated with circuit thrombosis. Methods: It was a single-center, observational, retrospective and prospective study conducted between January 2020 and April 2025. Patients aged ≥18 years undergoing dialysis without therapeutic or prophylactic anticoagulation were included, for up to 3 sessions each. Heparin-free dialysis was performed at the clinician’s discretion and retrospectively assessed using the Lohr and Swartz scale. Clinical, biological and dialysis-session data were collected. The primary endpoint was completion of the prescribed dialysis time, without circuit thrombosis or additional intervention. Secondary endpoint was the identification of thrombosis risk factors. Results: A total of 54 patients were included (97 sessions). The prescribed dialysis time was achieved without intervention in 86.6% of cases. Average session duration was 191.6 minutes, with an average blood flow of 339 mL/min. The success rate was 100% for sessions <150 min, 90.6% between 150-<210 min, and 81.1% beyond 210 min. For sessions longer than 210 min, we observed an average Kt/V online of 1.48. No patient characteristics demonstrated a statistically significant association with the occurrence of thrombosis. Among the dialysis-related parameters, only activated partial thromboplastin time (aPTT) differed significantly between sessions with and without circuit failure. Conclusion: The combined use of the NV-U membrane and citrate dialysate appears to be a feasible and effective strategy for performing anticoagulation-free HD in patients at risk of bleeding. Further prospective studies are warranted to confirm these findings and to optimize patient selection.