PB2311 COMPARISON BETWEEN THE EFFECTIVENESS OF CHRONIC PARTIAL RED BLOOD CELL EXCHANGE AND AUTOMATED RED BLOOD CELL EXCHANGE TRANSFUSION IN SICKLE CELL DISEASE: THE EXPERIENCE OF A HOSPITAL IN PORTUGAL
Authors: Araújo E. , Dutra R. , Dias M. 
Published: June 2019

Background:In sickle cell disease (SCD), red blood cell (RBC) transfusion has an important role in the management of emergency and elective settings. In both settings, transfusion may be administered by simple transfusion or by exchange transfusion, manual exchange transfusion or automated Exchange transfusion (AET). Chronic Transfusion Program (CTP) remains the gold standard therapy for stroke prevention and for patients with a severe disease who have inadequate response to hydroxyurea treatment.Aims:To evaluate the safety, efficacy and cost between the patients that underwent both AET and partial manual exchange transfusion (pMET) procedures.Methods:Retrospective observational cohort study of patients with SCD on CTP that have switched between pMET and AET. This study was carried out from 01/01/2017 to 31/12/2018 in a Tertiary Hospital in Portugal. Data on patient history, biological values, duration of the procedure, intervals between them, adverse events as well as the cost of material and human needs were collected and compared between both proceduresResults:A total of 6 patients met the inclusion criteria described. However, 1 patient was excluded from our study because of the lack of attendance to the CTP. During the study, we recorded 88 exchange procedures (42 pMET and 46 AET), both on peripherical venous access. From all those procedures the major concern was the poor venous access, which was the reason why 2 patients had returned to pMET. No major complication or alloimmunization was observed. The indications for CTP were cerebral vasculopathy (N = 2), stroke (N = 1) and recurrent vaso‐occlusive crisis with multiorgan failure (N = 2). For both procedures, target values were to obtain a pre‐exchange HbS level ≤30% for stroke and cerebral vasculopathy and ≤50‐60% for other indications. We documented in 11,4% of patients a higher HbS level prior to the next procedure (N = 10). Despite that all patients remained stable without any SCD related event. Both procedures were well tolerated and iron overload was well controlled. The duration of the exchange procedure was longer and the intervals between procedures were shorter with pMET. Annual RBC requirements per procedure were superior and the overall costs related with AET were 2,2 times higher – 18.180,93€ and 8.174,79€ AET and pMET, respectively (estimated cost per session AET: 790,48€ and pMET:389,28€). Since in our cohort we did not observe the interruption of chelation due to the switch, we did not include the cost for chelation.Summary/Conclusion:Our study shows, as described in literature, that AET allows a faster decrease in the HbS level immediately after exchange transfusion than pMET. Nonetheless, the HbS level before both procedures, performed during the same interval, were similar. We verified that pMET has a comparable efficacy with AET in terms of preventing the development or progression of chronic complications and that the cost per procedure is significantly higher with AET. However, in a clinical situation where it is important to rapidly reduce the HbS level, and/or where the control of the target HbS is stricter so that the patients are clinically controlled without an increase in hospital visits, AET is preferred. We conclude that AET is more effective in the rapid reduction of HbS and ferritin levels, as well as being less time consuming. Despite this, for the reasons described above, it is more cost‐effective to maintain both AET and pMET procedures.