A Comparison of Intra-Operative Isohemagglutinin Removal Techniques in Pediatric Heart Transplantation

Abstract

ABO-incompatible (ABO-I) heart transplantation (HT) is used in children <2 years of age to reduce waitlist times and mortality with outcomes comparable to ABO-compatible HT. This strategy is made safer by reducing isohemagglutinin titers (IT). Limited data exists comparing techniques for IT reduction. This study's aim was to compare the in vitro magnitude of IT removal and time required between membrane-based plasmapheresis (MP) and centrifuge-based plasmapheresis (CP) incorporated into the cardiopulmonary bypass (CPB) circuit. Two MP (Prismaflex) and two CP (Spectra Optia, Terumo BCT) circuits were incorporated into four separate CBP circuits primed with high titer type O donor whole blood. Assays were performed to determine baseline isohemagglutinin titers and then at 30 minute increments until completion of the run (two plasma volume exchanges) at two hours. There was a decrease in anti-A and anti-B IgM and IgG titers with both MP and CP. Mean anti-A and anti-B titer reduction was 4.625 titers (93.7% change) and 4.375 titers (93.8% change) using MP and CP, respectively. At 2 hours of apheresis, CP reduced 62.5% of all ITs to ≤ 1:4, while MP reduced 50% of ITs to ≤1:4. Both demonstrated similar hemolytic and thrombotic profiles. In this in vitro plasmapheresis model of IT reduction, both MP and CP incorporated into the CPB circuit can be used quickly and effectively to reduce circulating IT. While CP may have some greater efficiency, further study is necessary to verify this in vivo.