Prediction of survival after fetoscopic laser surgery for early-onset twin-to-twin transfusion syndrome

Objective: Data on early-onset twin-to-twin transfusion syndrome (TTTS) are scarce and, therefore, evidence-based counseling and management of these pregnancies are challenging. This study aimed to investigate survival rates and establish predictors of survival after fetoscopic laser surgery (FLS) for early-onset TTTS. Methods: This was an international multicenter retrospective cohort study of monochorionic diamniotic twin pregnancies complicated by TTTS diagnosed before 18 + 0 weeks' gestation that underwent FLS. The primary outcome was dual-twin survival at 28 days after birth. Secondary outcomes included survival of at least one twin and dual-twin demise at 28 days after birth. Monoamniotic twin, triplet and higher-order multiple pregnancies, pregnancies with chromosomal or structural fetal anomaly and TTTS cases not treated by FLS were excluded. Pre-, intra- and postoperative characteristics were analyzed using multivariable logistic regression analysis. Discriminative performance was assessed using receiver-operating-characteristics-curve analysis. Results: A total of 485 cases of early-onset TTTS that underwent FLS were included. The rates of dual-twin survival and survival of at least one twin at 28 days after birth were 51.5% (250/485) and 76.7% (372/485), respectively, while 23.3% (113/485) of cases resulted in dual-twin demise. Multivariable logistic regression analysis showed that absent or reversed end-diastolic flow (AREDF) in the donor umbilical artery (adjusted odds ratio (aOR), 0.487 (95% CI, 0.273–0.867)) and absent or reversed a-wave in the donor ductus venosus (aOR, 0.299 (95% CI, 0.110–0.810)) at the time of TTTS diagnosis were associated independently with decreased odds of dual survival, while higher gestational age at birth was associated with increased odds of both dual-twin survival (aOR, 1.172 (95% CI, 1.117–1.229)) and survival of at least one twin (aOR, 2.053 (95% CI, 1.699–2.481)). The model for dual-twin survival showed modest discriminative performance with poor overall fit. Conclusions: The presence of AREDF in the donor umbilical artery and absent or reversed a-wave in the donor ductus venosus, at the time of diagnosis of TTTS, and lower gestational age at birth were independent adverse predictors for dual-twin survival following FLS in cases of TTTS diagnosed before 18 weeks. Future studies should explore the impact of surgical technique on survival rates.