Birth prevalence of right ventricular outflow tract abnormalities in the recipient twin of monochorionic twin pregnancies complicated by twin-to-twin transfusion syndrome: amnioreduction versus fetoscopic laser coagulation treatment

ABSTRACT
Objective. Right Ventricular Outflow Tract Abnormalities (RVOTA) as pulmonary stenosis, atresia and insufficiency are typical cardiac anomalies of recipient twins (RTs) in untreated monochorionic diamniotic twin (MC/DA) pregnancies complicated by twin-to-twin transfusion syndrome (TTTS), affecting 8-12% of cases. The aim of this study was to compare birth RVOTA prevalence in TTTS pregnancies treated by fetoscopic laser surgery (FLS) versus by serial amnioreductions (AR).
Methods. We conducted a retrospective analysis of neonatal medical records of TTTS referred to our center to receive treatment. Serial ARs were the treatment up to 2004, when FLS has become the treatment. Neonatal cardiac outcomes were reviewed to assess RVOTA prevalence.
Results. Neonatal cardiac outcomes were available in 354 MC twins complicated by TTTS: 309 (87%) were treated by FLS and 45 (13%) by AR. All cases of RVOTA at birth involved the RT. Among 253 RTs born alive, 13 cases (5.1%) had RVOTA at birth. In FLS group, 221 (71%) RTs were born alive and 10 (4.5%) with RVOTA. In the AR group, 32 (71%) RTs were born alive and 3 (9.4%) with RVOTA. Occurrence of RVOTA was halved in FLS group (FLS = 4.5% vs AR = 9.4%, respectively) but this reduction did not reach statistical significance (P = 0.22).
Conclusions. In our experience, treatment for TTTS by FLS versus by AR was suggestive of a lower birthrate of RVOTA in recipient twins but did not eliminate it completely. Therefore, TTTS represents an indication for careful postnatal cardiologic evaluation, including an echocardiography, regardless of the type of prenatal treatment received.