Perinatal outcome of twin reversed arterial perfusion sequence: A single center's experience

Abstract

The twin reversed arterial perfusion (TRAP) sequence, also known as acardiac twinning, is a unique complication of monochorionic twin pregnancies that occurs in approximately one of 35,000 pregnancies and 1% of monozygotic twins [1]. The acardiac twin receives all of its blood from the pump twin through artery-toartery anastomosis, resulting in a retrograde flow of deoxygenated blood into the acardiac twin through the umbilical artery [2]. This results in poor or absent development of the heart and upper body in the acardiac twin and an increased risk of high-output cardiac failure, polyhydramnios, and the consequential death of the structurally normal pump twin [3]. Because of the high risk of perinatal death to the pump twin and polyhydramnios-related preterm delivery, an intervention to interrupt the blood flow to the acardiac twin is usually performed. A variety of minimally invasive treatment modalities, such as cord ligation, laser coagulation, interstitial laser therapy, and radiofre-ORIGINAL ARTICLE Korean J Obstet Gynecol 2012;55(8) ObjectiveTo report our experience of using radiofrequency ablation (RFA) to treat fetuses diagnosed with twin reversed arterial perfusion (TRAP) sequence and to evaluate the perinatal outcome of pump twins. MethodsTwenty-six fetuses diagnosed with the TRAP sequence were retrospectively analyzed between July 1998 and September 2011 at Asan Medical Center. Four were lost to follow-up after diagnosis and, therefore, were excluded from further evaluation. The perinatal outcomes of pump twins were evaluated by reviewing the medical records. ResultsTwenty-two fetuses were diagnosed with the TRAP sequence during the study period, including 15 monochorionic-diamniotic pregnancies and four monochorionic-monoamniotic pregnancies. Three patients had triplet pregnancies. The median gestational age at diagnosis was 17.4 weeks (range, 11.0 to 27.0 weeks). Of these 22 cases, in utero RFA was performed in 11 (50%), alcohol ablation in one (4.5%) and the remaining 10 (45.5%) underwent conservative management. The median gestational age at in utero intervention was 21.0 weeks (range, 17.6 to 25.0 weeks). The overall neonatal survival rate was 77% (17 of 22). The median gestational age at delivery was 37.3 weeks (range, 30.2 to 40.1 weeks). All of the surviving infants are doing well without any complications. ConclusionFor fetuses with the TRAP sequence, proper in utero treatment with RFA enables to continue the pregnancy with a good prognosis.

Intrafetal Laser Treatment for Selective Feticide in Monochorionic Multiple Pregnancies

“…The procedure ended after no Doppler flow to the acardiac fetus was confirmed ( fetoscopic photocoagulation of the anastomoses, 8,9 intrafetal RFA, 2,10,11 and intrafetal laser coagulation.…”

“…15 Intrafetal ablation using an Nd:YAG laser (1,064 nm wavelength) is optimal due to its greater coagulation effect; the laser's shorter diameter (400 µm, 18-to 20-gauge) compared with the RFA device (3 mm, 14-gauge) also allows the procedure to be performed in earlier gestational weeks. 11,12 Moreover, the techni ques required to perform intrafetal laser coagulation are relatively easier and widely usable, since the procedure requires similar training to amniocentesis using 18-and 20gauge needles.…”