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 recipient's cardiovascular status. Digoxin benefits a hydropic recipient but slightly worsens the donor's condition. Therefore, TTTS presenting with a hydropic recipient prior to fetal viability (approximately 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