Customizing anticoagulation strategies during leukapheresis to limit citrate exposure

Background and Objectives Leukapheresis has become a standard practice to collect CD34+ haematopoietic progenitor cells (HPC) from peripheral blood. Hypocalcemic toxicity (hypocalcaemia) is the most common complication during leukapheresis associated with citrate-based anticoagulation (AC) infusion. This report describes a new approach to limit citrate exposure by increasing the inlet:AC ratio while maintaining original inlet flow rates on the device in order to decrease the AC infusion rate. Materials and Methods A retrospective analysis was performed on 63 autologous and 29 allogeneic HPC collections. Procedures were started at a conservative inlet:AC ratio of 12:1 with gradual ratio ramping (RR) during the procedure, or at an inlet:AC ratio of 13:1 or higher (HIR), with constant inlet flow rates. The clinical decision to change the ratio was based on platelet counts and concomitant medications, such as systemic anticoagulants. Symptoms of citrate toxicity were treated by calcium supplementation. Results Customization of AC management with RR or HIR was performed in 91 of 92 procedures with a final inlet:AC ratio of 13:1–20:1, under careful supervision for platelet clumping episodes. Notably, 33 procedures were completed in individuals chronically treated with aspirin and/or warfarin. Citrate infusion gradually decreased with higher inlet:AC ratios, without affecting procedure time. The HIR strategy resulted in significantly smaller AC infusion volumes compared to RR, and lower frequency of calcium administration. CD34+ collection efficiency was not influenced by increasing inlet:AC ratios. Conclusion Customization of the inlet:AC ratio while maintaining a constant, stable inlet flow rate is effective in limiting citrate exposure during leukapheresis.