Simulation of therapy in a model of a nonhydropic and hydropic recipient in twin-twin transfusion syndrome

Objective This study was undertaken to model the sequence of events that occurs after amnioreduction, laser therapy, and digoxin administration in twin-twin transfusion syndrome (TTTS) with and without a hydropic recipient twin. Study design We added amnioreduction, laser therapy, and digoxin administration to our mathematical TTTS model and simulated combinations of these therapies. Results With a nonhydropic recipient, simulated amnioreduction delays the onset of hydrops. Conversely, with a hydropic recipient, amnioreduction aggravates the degree of hydrops. Furthermore, amnioreduction increases the transplacental fluid flow and may temporarily cause a hydropic donor. Laser therapy terminates the cause of recipient hydrops. Digoxin reduces the degree of recipient hydrops, but increases arteriovenous fetofetal transfusion. Conclusion Laser therapy is superior in TTTS with a hydropic recipient, because simulated amnioreduction aggravates the recipientʹs cardiovascular status. Digoxin benefits a hydropic recipient but slightly worsens the donorʹs condition. Therefore, TTTS presenting with a hydropic recipient prior to fetal viability ( 26 weeks) may be best treated with laser therapy, whereas more advanced gestations may be offered digoxin administration plus amnioreduction, to delay the progression of TTTS.