Twin-twin transfusion syndrome: intraamniotic pressure measurement in the assessment of volume reduction at serial amniocenteses

Controlled amnioreduction for twin-to-twin transfusion syndrome

Background:

Twin-to-twin transfusion syndrome (TTTS) is a severe condition causing preterm delivery, fetal death, and neurodevelopmental disorders. This study presents a data-based controlled amnioreduction (AR) protocol composed of sequential amniodrainage in treatment of TTTS.

Methods:

A total of 18 procedures were performed in 11 TTTS pregnancies at 17 to 34 weeks of gestation. The amniotic pressure was measured along with sequential removal of the amniotic fluid, 500 mL each step. The umbilical artery systolic/diastolic (S/D) ratio for each twin was measured pre- and post-AR. Long-term neurodevelopmental outcomes of all TTTS survivors were evaluated from parental answers to a phone survey.

Results:

The amniotic pressure decreased exponentially with the increased volume of removed amniotic fluid until a plateau was obtained. Changes of the S/D ratio between pre- and post-AR procedure did not reveal a clear tendency. The survival rate was 86.4% although 91% of all twins were at Quintero stage III. Long-term neurodevelopment outcomes in the 19 surviving twins were 68.4% optimal, 26.3% suboptimal, and 5.3% abnormal.

Conclusion:

The controlled AR procedure resulted in a relatively high rate of twin survival with favorable long-term neurodevelopment outcomes.

Amniodrainage-Induced Circulatory Dysfunction in Women Treated for Twin-To-Twin Transfusion Syndrome

Twin-to-twin transfusion syndrome (TTTS) in monochorionic-diamniotic twin pregnancies usually requires fetoscopic laser ablation (FLA) followed by amniodrainage (AD). Perioperative maternal hemodynamic changes and hemodilution have been observed. Little is known about the underlying pathophysiology. We aimed to evaluate the impact of high volume amniodrainage on intrauterine pressure, placental thickness and maternal blood characteristics. A total of 18 cases of TTTS were included in this prospective pilot study. All patients were treated with FLA and subsequent AD. Intrauterine pressure and placental thickness were assessed before, during and after amniodrainage. Maternal hemoglobin, hematocrit and serum albumin were measured at admission and 24 h after the intervention. Amniodrainage led to a decrease in mean intrauterine pressure (from 30.1 ± 8.1 mmHg to 17.6 ± 3.6 mmHg (p < 0.001)) and an increase in mean placental thickness (from 16.8 ± 6.4 mm to 31.83 ± 8.64 mm (p < 0.001)). There was a positive correlation between changes in placental thickness and the amount of amniodrainage during intervention (Pearson's Rho 0.73; p = 0.001). Hematocrit decreased from 33.4 ± 3.8 (%) to 28.4 ± 3.5 (%), i.e., an increase in relative blood volume by 18 ± 10.2% (p < 0.001). Albumin decreased from 37.9 ± 0.9 g/L to 30.7 ± 2.2 g/L, i.e., an increase in relative plasma volume by 24 ± 8.1% (p < 0.001). Amniodrainage leads to uterine decompression, increased placental thickness and subsequent maternal hemodilution. We propose the term "amniodrainage-induced circulatory dysfunction" for these specific maternal hemodynamic changes in the treatment of twin-to-twin transfusion syndrome.

Septostomy with amniodrainage in the treatment of twin-to-twin transfusion syndrome: a 16-case report

OBJECTIVE

To report the treatment results of 16 monochorionic and diamniotic gestations cases, which had complications due to the twin-to-twin transfusion syndrome (TTTS), the neonatal and other possible complications of the septostomy associated to the amniodrainage.

METHOD

Based on ultrasonographic findings, 16 pregnant women were diagnosed with the twin-to-twin transfusion syndrome (TTTS). These cases were divided in two groups: one of them included the fetuses without hydrops and the second included the "recipient" fetuses with hydrops. The therapy measures included septostomy with or without amniodrainage. The following parameters were evaluated: gestational age at the time the septostomy was performed, volume of drained amniotic fluid, gestational age at delivery, birth weight, postnatal evolution, and procedure complications.

RESULTS

The average gestational age for this procedure was of 23.6 weeks (from 14 weeks and 1 day to 33 weeks). The gestational age for the septostomy until the delivery was of 8.18 weeks (from 1.0 to 21.3 weeks). The survival rate in the group without hydrops was of 68.7%, while in the second group it was of 25%. Some of the complications were as follows: two cases of premature membrane rupture and one case of preterm labor.

CONCLUSION

Septostomy with amniodrainage, when performed on the initial stages and on earlier gestational ages has good perinatal results.

Twin-twin transfusion syndrome: etiology, severity and rational management

The twin-twin transfusion syndrome is a serious complication of monochorionic twin pregnancies. Partly as a result of an inadequate understanding of the pathophysiology of the syndrome, there is a lack of consensus in clinical management. We sought to review the available information on the etiology of twin-twin transfusion syndrome, to identify parameters that contribute to the severity of the syndrome, and propose a rational management plan based on pathophysiology, clinical presentation and the efficacy of therapies. We therefore amalgamated recent advances in twin-twin transfusion syndrome computer modelling and clinical studies, particularly on therapeutic outcomes. We found that the oligo-polyhydramnios sequence that defines twin-twin transfusion syndrome prenatally represents a wide continuum of severity in the imbalance between the fetoplacental circulations of both twins. In severe twin-twin transfusion syndrome cases, in which the circulatory imbalance deteriorates beyond fetal control, fetoscopic laser therapy of all anastomoses along the placental vascular equator is predicted to have significantly better survival rates and fewer neurological sequelae than amnioreduction. In contrast, mild twin-twin transfusion syndrome cases have better outcomes after one or at most a few amnioreductions than laser therapy, as a result of significantly fewer procedure-related risks. In conclusion, optimal individual therapy may possibly achieve an 85% survival rate in twin-twin transfusion syndrome, but requires advancement in non-invasive criteria that predict the severity of the syndrome. Identifying such criteria is a future challenge. For the interim, twin-twin transfusion syndrome diagnosed before 26 weeks' gestation has significantly better survival rates and fewer neurological sequelae after laser therapy than amnioreduction. Twin-twin transfusion syndrome diagnosed after 26 weeks can best be treated by amnioreduction, or delivery. Contrary to previous claims, fetoscopic laser therapy has outgrown its experimental status. Although improvements in technique and technology are likely, laser placental ablation has a firm scientific and clinical basis.

Twin-to-twin transfusion syndrome: treatment by amniodrainage and septostomy

OBJECTIVE

Severe previable twin-to-twin transfusion syndrome (TTTS) is associated with a high fetal loss rate and is therefore usually treated. In this paper, serial amniodrainage and inter-twin septostomy are reviewed in terms of technical aspects and fetal outcome.

STUDY DESIGN

A review of the literature using a MEDLINE DATA search between 1990 and 2000 was done in order to describe the mechanisms and technical aspects of both procedures with their physiopathological consequences. In addition, data from our experience with septostomy are given.

RESULTS

Amniodrainage increases survival rate, with outcome ranging from 40 to 87% (mean: 56%). Inter-twin septostomy is associated with a mean fetal survival rate ranging from 57 to 83% (mean: 70%).

CONCLUSION

In severe TTTS, amniodrainage and septostomy are simple therapeutic alternatives with a survival rate similar to what is currently reported for laser coagulation of placental vessels.

Placental anatomy, fetal demise and therapeutic intervention in monochorionic twins and the transfusion syndrome: new hypotheses

OBJECTIVE

Monochorionic twins with circulatory sharing have an incompletely understood response to acute hemodynamic events. We relate placental vascular anatomy with, first, the response to (a) acute fetal demise and (b) laser interrupted placental anastomoses and, second, the efficacy of current and possibly future therapeutic interventions in twin-twin transfusion syndrome.

DESIGN

Hemodynamic response to acute fetal demise and laser interrupted anastomoses is analysed using the model previously developed for monochorionic twins. Efficacy of therapeutic interventions in twin-twin transfusion syndrome is analysed by combining the estimated incidence of placental anastomotic patterns with three previously proposed pathophysiologic mechanisms.

RESULTS

Fetal demise may cause sequelae for the co-twin in all anastomotic patterns except unidirectional arteriovenous and single venovenous anastomoses which are predicted to be hemodynamically harmless. In twin-twin transfusion syndrome, laser interruption of all anastomoses mitigates further transfusion. This is of benefit for the twins in equally but not in unequally shared placentas. Analysis predicts that approximately 75% fetal survival could be achieved interrupting only arteriovenous anastomoses. Amniocentesis may only prolong pregnancies that lack progressively increasing discordance, assuming that placental anastomoses remain patent following polyhydramnios. This proposed mechanism of action predicts current therapeutic efficacy accurately and could explain the significantly higher reported serious morbidity compared with laser (15/81 = 19+/-5% versus 4/146=3%, P=0.00004). However, if therapeutic interventions could match the syndrome's individual placental anatomy, the analysis suggests approximately 10-15% laser related mortality (premature rupture of membranes) and <3% severe morbidity could possibly become achievable goals.

CONCLUSION

Our predictions allow clinical testing. This information may contribute to an improved management of monochorionic twins.

Successful outcome with serial amniocenteses for polyhydramnios complicating cystic adenomatoid malformation of the lung

Hydrops fetalis secondary to congenital cystic adenomatoid malformation of the fetal lung is almost invariably a lethal condition. This poor prognosis may be attributed to the combined effects of tissue compression from the thoracic space occupying lesion and premature delivery of a hydropic baby following rupture of the membranes in the presence of polyhydramnios. We describe a successful outcome with serial amniocenteses. Partial in utero resolution of the lung lesion with complete return to normal of the aberrant liquor volume was documented, and a live infant was delivered at term.