Twin-to-twin transfusion syndrome: a case report. Antepartum prediction of underlying placental vascular pattern in monochorionic twin pregnancies may be possible

Abstract

A case of twin-to-twin transfusion syndrome is described. Comparing data of serial antepartum ultrasonography with a haemodynamic model suggests the possibility of predicting the underlying placental vascular anatomy. It is suggested that serial ultrasonography, including full biometry, pulsatility indices of the umbilical arteries, foetal echocardiography, assessment of amniotic fluid indices and foetal bladder filling could serve as ultrasound parameters for pattern recognition of the underlying placental vascular anomaly. Biometry should be plotted serially in a difference/ average plot. Future application of such intensive ultrasound monitoring in monochorionic twins, as soon as monochorionicity is established, may distinguish those monochorionic twins who may benefit from treatment from those whom it would be better only to observe.

Amniotic fluid and hemodynamic model in monochorionic twin pregnancies and twin-twin transfusion syndrome

“…3A). Although this behavior has been observed clinically (11,35,39), it contradicts the predictions of our previ- ous model (34), which only shows symmetric deviations from the normal growth curve (see open circles in Fig. 3A).…”

“…Steadystate discordant growth may develop if AV anastomotic transfusion is compensated by oppositely directed transfusion, either from other deep oppositely directed AV or superficial arterioarterial (AA) or, less frequently, venovenous (VV) anastomoses. Although the fetal growth predictions of this model are highly consistent with clinical observations (23,35,37,39), the model did not include an assessment of amniotic fluid dynamics.…”

Classification of discordant fetal growth may contribute to risk stratification in monochorionic twin pregnancies

“…Here, virtually equal but oppositely directed arterio±venous and compensating flows ensue, which can be large and measurable 8,19 , forcing fetal discordance to develop proportional to the average growth of both twins. Consequently, DAR was predicted to become a constant 2 and hence to have a virtually zero rate of change 13,20 . Although large discordance can be possible, depending on the resistance ratio between arterio±venous and compensating anastomoses, favorable outcome has been associated with these cases 7,8,13±15,20 .…”