Continuous venovenous hemodialysis (CVVHD) with citrate calcium reduces postoperative bleeding complications after cardiac surgery

Objective: Continuous renal replacement therapy is the preferred method of treatment of acute renal failure after cardiac surgery. Efficient anticoagulation of the extracorporeal circulation is essential to prevent clotting of the system. Regional anticoagulation using citrate is assumed to reduce the risk of systemic bleeding. The present study investigates the safety of citrate dialysis (CI-CA) after cardiac surgery in comparison with conventional procedures using heparin (HEP).

Methods: In a prospective randomized, non-blinded monocentric trial (11/2008–02/2009), we compared continuous venovenous hemodialysis (CVVHD) using heparin (Diapact CRRT B. Braun AG, Germany) (n=26) against a citrate calcium method (Ci-Ca multifiltrate Fresenius Medical Care, Germany) (n=24). In the HEP group, the system was primed with 600 IE heparin and run with a minimum of 15000IE/24h of heparin on the basis of HEP test controls (0.4–0.7). Our primary end points were bleeding events, death, cardiac arrhythmia, creatinine levels and filter occlusion.

Results: There were no differences between the demographic data of the patient groups and no significant difference as far as the surgical procedures performed and postoperative catecholamine support are concerned. The incidence of bleeding was significant higher in the HEP group. No differences were found for the items: mortality, ICU stay, respirator time and arrhythmias.

Conclusion: CiCA proved effective and safe. A significant prolongation of filter patency was noted. A significant difference in mortality was not registered within the small study population. Changes of plasmatic calcium levels representing a potential risk of cardiac arrhythmia or cardiac output reduction did not occur.