Optimal method and timing of intrauterine intervention in twin reversed arterial perfusion sequence: case study and meta-analysis.

INTRODUCTION: The objective of this study was to define the optimal method and timing of intervention in twin reversed arterial perfusion (TRAP) sequence. MATERIAL AND METHODS: During a period of 20 years (1993-2013), we performed endoscopic laser coagulation of umbilical cord vessels or intrafetal laser in 67 pregnancies with TRAP sequence. These data were combined with those reported in the literature to determine the survival rate of the pump twin for different methods and timing of interventions. RESULTS: A variety of techniques were used to interrupt the blood supply to the acardiac twin. Most procedures were performed at or after 16 weeks, and with most methods the survival rate of the pump twin was about 80%. Good results were also obtained for triplet pregnancies. In 18 of 30 cases (60%) diagnosed at 11-14 weeks, there was spontaneous cessation of flow in the acardiac twin before planned intervention at 16-18 weeks, and in 11 of these (61.1%) the pump twin died or suffered brain damage. In 103 pregnancies treated by intrafetal laser at 12-27 weeks, there was no correlation between gestational age at treatment and survival rate, but there was an inverse association between gestational age at treatment and gestational age at birth. DISCUSSION: In TRAP sequence, survival may be improved by elective intervention at 12-14 weeks.

Embryo reduction in dichorionic triplets to dichorionic twins by intrafetal laser.

OBJECTIVE: To describe a new technique for embryo reduction (ER) in dichorionic triplet (DCT) pregnancies. METHODS: In 22 DCT pregnancies, ER to dichorionic twins was carried out at 11.3-13.9 weeks' gestation by ultrasound-guided laser ablation of the pelvic vessels of one of the monochorionic twins. RESULTS: Intrafetal laser was successfully carried out in all cases, but ultrasound examination within 2 weeks of the procedure demonstrated that the co-twin had died in 11 cases and was alive in the other 11. In the dichorionic group there was one miscarriage at 23 weeks due to cervical incompetence and in the other 10 cases there were two live births at a median gestational age of 35.0 (range 32.2-37.1) weeks. In the 11 cases where both monochorionic fetuses died the separate triplet was live born at a median gestation of 38.0 (range 32.2-40.5) weeks. CONCLUSIONS: In the management of DCT pregnancies, ER to dichorionic twins by intrafetal laser is an additional option to the traditional ones of expectant management, ER by intrafetal injection of potassium chloride (KCl) to monochorionic twins or ER by KCl to singleton.