Diagnosis, Pathophysiology, and Treatment of Chronic Twin-to-Twin Transfusion Syndrome

Abstract

The discovery of a ‘stuck twin’ during an ultrasound examination has often been equated with twin-to-twin transfusion based to a great extent on postnatal confirmation of discordant fetal size and hemoglobin concentration. However, the diagnosis of twin-to-twin transfusion cannot be made with certainty after birth since virtually all monochorionic gestations have placental anastomoses and there are many causes of growth deficiency and abnormal hemoglobin concentration. The purpose of this study is to investigate the pathophysiology of chronic twin-to-twin transfusion syndrome and apply the findings to the development of a anagement algorithm. In 42 twin gestations with stuck twin associated with acute hydramnios, we performed targeted ultrasound cordocentesis in each fetus and therapeutic amniocentesis. The diagnosis of chronic twin-to-twin transfusion syndrome required: sonographic evidence of monochorionicity; rapid reaccumulation of fluid after amniocentesis; discordant fetal size, and divergent fetal hematocrit measurements with at least one above or below the 95% confidence interval for gestational age. These criteria were met in 20 of 42 (48%) pregnancies. The mean gestation was 23.8 ± 2 weeks (range 21-27 weeks). In 4 pregnancies, the transfer of adult RBCs from the donor to the recipient was documented. Monochorionicity was confirmed in all postnatally. All recipients had polycythemia and hyperproteinemia. Hydrops developed only in the recipient twin (6 of 20) and was associated with an elevated umbilical venous pressure. All pregnancies were treated with aggressive serial therapeutic amniocenteses. There was no objective evidence that amniocentesis altered the magnitude of the shunt. In addition, 1 patient chose pregnancy termination, 3 a selective fetocide of the donor twin, and 4 transfusion therapy. The mean gestation at delivery was 29 + 4 weeks and the perinatal mortality rate 58% (23 of 40 fetuses). Survival was significantly lower when symptoms appeared < 25 weeks (10 of 30 vs. 7 of 10, p = 0.04). The presumptive diagnosis of twin-to-twin transfusion is frequently erroneous and an accurate diagnosis required antenatal evaluation. Hydrops results from heart failure secondary to a combination of polycythemia and hyperproteinemia. Because no antenatal therapy is clearly effective and the likelihood of neonatal survival is greater when symptoms first appear ≥ 24 weeks, an invasive evaluation should be limited to those pregnancies which either present < 25 or ≥ 25 weeks with a hydropic fetus.

Amniotic Septostomy for the Treatment of Twin Oligohydramnios-Polyhydramnios Sequence

“…Elliot et al [21] suggested that amniocentesis decreases amniotic fluid pressure resulting in reversal or stabilization of blood transfer between the twins and improved placental perfusion. Weiner and Ludomirski [2] and Meagher et al [25] measured amniotic fluid pressure prior to therapeutic amniocentesis and found it increased when compared with normal pregnancies. The pressure decreased following reduction amniocentesis.…”

“…By the eleventh day after amniocentesis, the amniotic fluid in both sacs had normalized and remained as such until delivery at 35 5 / 7 weeks. The sudden resolution of the syndrome after one or more amniocenteses, and the failure to document an increase in urine production in the stuck twin in the few cases where it was measured [2,24], are not consistent with the explanation that the postprocedural increase in the amniotic fluid around the stuck twin is always the direct result of improved fetal renal perfusion. We propose that, in cases where resolution of the syndrome occurred unexpectedly, the amnion separating the twins was inadvertently punctured at the time of amniocentesis.…”

“…[Reprinted from 40, with permission. ] Due to differing diagnostic criteria and ascertainment bias, the estimated incidence of this syndrome in twin gestations has ranged widely between 1 and 26% [2,[4][5][6]. The data on perinatal mortality have also been affected by diagnostic inconsistencies and the general improvements in perinatal survival through the years.…”

Pathophysiology of twin to twin transfuzion syndrome

“…Blizanci koji se u drugom trimestru prezentuju sa teškim TTTTS, mogu imati hemodinamski disbalans u prvom trimestru, koji se manifestuje kao diskordantna povećana nuhalna translucenca (NT) u 10. do 14. nedelji gestacije [13]. Ovo je od značaja, jer je NT primarno screening za aneuploidije u multiploj trudnoći.…”

“…Ovo se vidi kod 32% MC trudnoća, a od njih će 43% kasnije razviti TTTTS [13]. Međutim, upotrebljivost ovih subjektivnih nalaza u predikciji TTTTS ostaje diskutabilna [39].…”