Intrauterine transfusion combined with partial exchange transfusion for twin anemia polycythemia sequence: Modeling a novel technique F. Slaghekke a, * , J.P.H.M. van den Wijngaard b, c , J. Akkermans a , M.J.C. van Gemert b , J.M. Middeldorp a , F.J. Klumper a , D. Oepkes a , E. Lopriore d a Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands b Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands c Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands d Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands article info Article history: Accepted 26 January 2015 Keywords: Twin anemia polycythemia sequence Intrauterine transfusion Partial exchange transfusion Mathematical model abstract Introduction: Twin anemia-polycythemia sequence (TAPS) is a newly described disease in mono- chorionic twin pregnancies, characterized by large inter-twin hemoglobin differences. Optimal man- agement for TAPS is not clear. One of the possible treatment modalities is intrauterine blood transfusion (IUT) in the donor with or without combination of partial exchange transfusion (PET) in the recipient. Methods: We applied a computational model simulation to illustrate the mechanism of IUT with and without PET in TAPS occurring after laser surgery for twinetwin transfusion syndrome (TTTS). Model simulations were performed with the representative anastomotic pattern as observed during laser intervention, and after placental dye injection. Results: The model was tested against different cases where IUT was combined with PET for the treat- ment of post-laser TAPS. Model simulations using the observed anastomotic pattern showed a significant reduction of hyperviscosity in the recipient after IUT/PET compared to IUT without PET. Discussion: In this model simulation we show that the addition of PET to IUT reduces the severity of polycythemia in the recipient. PET may thus be important to prevent complications of hyperviscosity. Conclusion: This model simulation shows the beneficial effect of PET for the recipient in TAPS cases treated with IUT. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Monochorionic twin pregnancies can be complicated by the twin anemia-polycythemia sequence (TAPS), which is a chronic form of feto-fetal transfusion. TAPS is characterized by large inter-twin he- moglobin (Hb) differences but without signs of the oligo- polyhydramnios sequence. TAPS placentas are characterized by the presence of only few, miniscule vascular anastomoses [1]. The inci- dence of TAPS varies between 1 and 5% in spontaneous TAPS [2e5] and up to 16% in post-laser TAPS [6,7]. TAPS can be diagnosed antenatally or postnatally. Prognosis of TAPS can vary from two healthy neonates with hematological problems to severe neonatal morbidity, such as limb necrosis, severe cerebral injury or perinatal death. Antenatal management options include expectant management, induction of labor, intrauterine blood transfusion (IUT) with or without combina- tion of partial exchange transfusion (PET), selective feticide or (repeat) fetoscopic laser surgery [8e11]. Treatment with IUT at least tempo- rarily improves the condition of the donor twin, however, the transfer of transfused red cells to the already polycythemic recipient may worsen its hyperviscosity and increases the risk for associated com- plications such as limb necrosis and severe cerebral injury [6,12]. The PET procedure implies replacement of the polycythemic fetal blood with saline solution and leads to a reduction of hyperviscosity. In this study we tested a model simulation against different cases of IUT in combination with PET. With this model we illustrate the mechanism of IUT with PET compared to IUT without PET. 2. Methods We selected different post-laser TAPS cases treated with IUT in combination with PET with full details of vascular anastomotic pattern during laser treatment and * Corresponding author. Division of Fetal Medicine, Department of Obstetrics, K6, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands. Tel.: þ 31 (0) 71 5262896; fax: þ31 (0) 71 5266741. E-mail address: f.slaghekke@lumc.nl (F. Slaghekke). Contents lists available at ScienceDirect Placenta journal homepage: www.elsevier.com/locate/placenta http://dx.doi.org/10.1016/j.placenta.2015.01.194 0143-4004/© 2015 Elsevier Ltd. All rights reserved. Placenta xxx (2015) 1e4 Please cite this article in press as: Slaghekke F, et al., Intrauterine transfusion combined with partial exchange transfusion for twin anemia polycythemia sequence: Modeling a novel technique, Placenta (2015), http://dx.doi.org/10.1016/j.placenta.2015.01.194