Filter life span in postoperative cardiovascular surgery patients requiring continuous renal replacement therapy, using a postdilution regional citrate anticoagulation continuous hemofiltration circuit

BACKGROUND: Regional citrate anticoagulation (RCA) is the recommended standard for continuous renal replacement therapy (CRRT). This study assesses its efficacy in patients admitted to critical care following cardiovascular surgery and the influence of standard antithrombotic agents routinely used in this specific group. METHODS: Consecutive cardiovascular surgery patients treated with postdilution hemofiltration with RCA were included in this prospective observational study. The primary outcome of the study was CRRT circuit life-span adjusted for reasons other than clotting. The secondary outcome evaluated the influence of standard antithrombotic agents (acetylsalicylic acid [ASA], low molecular weight heparin [LMWH] or fondaparinux as thromboprophylaxis or treatment dose with or without ASA) on filter life. RESULTS: Fifty-two patients underwent 193 sessions of continous veno-venous hemofiltration, after exclusion of 15 sessions where unfractionated heparin was administered. The median filter life span was 58 hours. Filter life span was significantly longer in patients receiving therapeutic dose of LMWH or fondaparinux (79 h [2–110]), in comparison to patients treated with prophylactic dose of LMWH or fondaparinux (51 h [7–117], p < 0.001), and patients without antithrombotic prophylaxis (42 h [2–91], p < 0.0001). 12 bleeding episodes were observed; 8 occurred in patients receiving treatment dose anticoagulation, 3 in patients receiving prophylactic dose anticoagulation and 1 in a patient with no antithrombotic prophylaxis. CONCLUSIONS: A postdilution hemofiltration with RCA provides prolonged filter life span when adjusted for reasons other than clotting. Patients receiving treatment dose anticoagulation had a significantly longer filter life span than those who were on prophylactic doses or ASA alone.