616: Delivery outcomes of monochorionic twins without standard twin twin transfusion staging criteria undergoing laser photocoagulation

Fetoscopic laser photocoagulation (FLP) has been used to treat monochorionic diamniotic (MCDA) twins who demonstrate complications of shared chorionicity without meeting standard twin twin transfusion syndrome (TTTS) criteria for amniotic fluid discordance (AFD). The gestational age and survival at delivery of this group remain undefined. We performed a single center retrospective analysis of 277 subjects undergoing FLP between 2012 and May 2019. Seventy-six of these cases had AFD without meeting standard TTTS staging criteria. In our group, one twin (identified donor) presented with a MVP > 2cm or the second twin (identified recipient) with a MVP < 8 cm or a combination of the two. FLP was performed based on echocardiographic evidence of cardiomyopathy (abnormal myocardial performance indices), abnormal arterial or venous Dopplers, isolated oligohydramnios or polyhydramnios, or a combination of these findings (Table 1). Subjects were divided into two groups based on presence (Group 1) or absence of selective intrauterine growth restriction (Group 2). We reviewed gestational age and survival at time of delivery. Delivery outcomes were available in 74 (97%) of pregnancies, summarized in Table 2. Group 1 had an average gestational age at delivery of 28.5 weeks. Survival of the donor was 52.2% and survival of the recipient was 78.3%. Survival of one or both twins was 78.3% and for both twins was 52.2%. In Group 2, the average gestational age at delivery was 29.9 weeks. Survival of the donor was 75% and survival of the recipient was 89.3%. Survival of one or both twins was 89.3% and for both twins was 75%. Fluid discordant MCDA twins may be complicated by echocardiographic evidence of cardiomyopathy or abnormal arterial or venous Dopplers without TTTS. A comparison group of expectant management is missing from the literature to understand if intervention increases survival in these cases. Careful consideration of treatment options should be utilized when counseling patients with MCDA pregnancies who do not meet standard staging criteria for TTTS.View Large Image Figure ViewerDownload Hi-res image Download (PPT)