Fetoscopic laser coagulation in 1020 pregnancies with twin-to-twin transfusion syndrome demonstrates improvement of double survival rates

OBJECTIVE: To investigate the growing experience and learning curve of fetoscopic laser coagulation of the placental vascular anastomoses in severe mid trimester twin-to-twin transfusion syndrome (TTTS) and its influence on perinatal outcome in a single center setting.

METHODS: Between 01/1995 and 03/2013 we performed laser therapy in 1020 consecutive pregnancies with TTTS between 15.1 and 27.4 weeks of gestation. We compared perinatal outcome in blocks of five sequential groups. We took several covariates into account in order to adjust for case mix and to demonstrate learning curves and conditions of success rates.

RESULTS: The percentage of pregnancies with survival of both fetuses increased from 50% (n = 100) in the first 200 cases to 69.5% (n = 153) in the last 220 cases (P = 0.018 for trend) and the overall survival rate for both fetuses in the complete series of 1019 cases with known outcome was 63.3% (n = 645). The survival rate of at least one fetus increased from 80.5% (161/200) in the first group to 91.8% (202/220) in the last group (P = 0.072 for trend) and the overall survival rate of at least one fetus in the complete series was 86.7% (883/1019). In the total population, the mean gestational age at delivery of pregnancies with at least one liveborn neonate was 33.7 (SD 3.2) weeks with a mean interval of 12.9 (SD 4.0) weeks between the intervention and delivery. Among the first two groups 124 pregnancies had anterior placentas and were treated with a 0° fetoscope. These cases had the poorest overall outcome with a double survival rate of 44.4% (55/124), which increased to 65.1% (207/318; P = 0.001) after the introduction of a 30° fetoscope for cases with anterior placental location. The success rate for double survival reached a plateau of 69% in the third group and this was not different for another operator, who was trained hands-on and performed 174 procedures in groups 4 and 5.

CONCLUSION: We report the largest single center experience for laser coagulation in TTTS. We observed a continuous increase in double survival rates owing to the growing experience based on the learning curve, refinements of fetoscopic instruments and techniques. These data provide strong arguments for centralization of minimally invasive intrauterine surgery in specialized high-volume centers.