Predictors of fetal death, neonatal survival and neurological outcomes in severe twin-twin transfusion syndrome treated by laser ablation of placental vessels

OBJECTIVES

To identify predictors of outcomes in severe twin oligo-polyhydramnios sequence (TOPS) with or without twin anemia-polycythemia sequence (TAPS) and/or selective fetal growth restriction (SFGR) treated by laser ablation of placental vessels (LAPV).

METHODS

Analysis of cases treated from 2011 to 2022. Variables evaluated Prenatal predictors: stages of TOPS, presence of TAPS and/or SFGR; pre-LAPV fetal ultrasound parameters; peri-LAPV variables. Perinatal predictors: GA at birth; birthweight; Apgar scores; transfontanellar ultrasonography (TFUS).

OUTCOME VARIABLES

fetal death, neonatal survival, infant's neurodevelopment. Binary logistic regression analyses were performed to detect predictors of outcomes.

RESULTS

265 cases were included. Predictors of post-LAPV donor fetus' death were delta EFW (p:0.045) and absent/reverse end-diastolic flow in the umbilical artery (AREDF-UA) (p < 0.001). The predictor of post-LAPV recipient fetus' death was hydrops (p:0.009). Predictors of neonatal survival were GA at birth and Apgar scores. Predictors of infant's neurodevelopment were TFUS and pre-LAPV middle cerebral artery Doppler (MCAD) for the donor twin; and pre-LAPV ductus venosus' flow and MCAD for the recipient twin.

CONCLUSIONS

Prediction of fetal death, neonatal survival and infant's neurodevelopment is possible in cases of TOPS associated or not with SFGR and/or TAPS that were treated by LAPV.

The High-Risk Profile of Selective Growth Restriction in Monochorionic Twin Pregnancies

The present review aims to provide a critical appraisal of the sonographic diagnosis and follow-up and to evaluate the optimal clinical management of monochorionic twin pregnancies where one of the twins is complicated by selective fetal growth restriction (sFGR). The classification is based on the umbilical artery (UA) diastolic flow reflecting the outcome. If the sFGR twin has positive diastolic flow (Type I) then the prognosis is good, and it does not require close surveillance. Biweekly or weekly sonographic and Doppler surveillance and fetal monitoring are recommended strategies to detect unpredictable complications in type II and type III forms, which are defined by persistently absent/reverse end-diastolic flow (AREDF) or cyclically intermittent absent/reverse end-diastolic flow (iAREDF) in the umbilical waveforms, respectively. The latest forms are associated with an increased risk of unexpected fetal demise of the smaller twin and 10-20% risk of neurological injury in the larger twin in addition to the overall risk of prematurity. The clinical course can be affected by elective fetal therapy ('dichorinization' of the placenta with laser or selective fetal reduction) or elective delivery in the presence of severe fetal deterioration. The prediction of the clinical outcome in complicated cases of type II and III sFGR cases remains elusive. Novel routines in fetal and placental scans in order to predict neurological impairments and unexpected fetal death to optimize the delivery time-point are needed.

Fetal anemia in monochorionic twins: a review on diagnosis, management, and outcome

INTRODUCTION

Monochorionic twins may develop fetal anemia when blood is unequally distributed via the placental vascular anastomoses. This review focuses on the causes of fetal anemia in complicated monochorionic twins and highlights the differences in management and outcome.

AREAS COVERED

Fetal anemia can occur in the context of twin anemia polycythemia sequence (TAPS), chronic twin-twin transfusion syndrome (TTTS) and acute peripartum TTTS, and in cotwins after single fetal demise. Diagnosis of fetal anemia is based on abnormal Doppler ultrasound measurements. Management options include fetoscopic laser surgery, intrauterine blood transfusion, or expectant management, depending on the type of complication and the severity of the disease. In all complications, fetal anemia may lead to perinatal mortality, neonatal morbidity, severe cerebral injury, and long-term neurodevelopmental impairment. In TAPS specifically, anemic donors may also show bilateral deafness.

EXPERT OPINION

Knowledge on the diagnosis and optimal treatment in TTTS is nowadays widespread, but caregivers often fail to distinguish TAPS from acute peripartum TTTS at birth. A full blood count including reticulocyte count is required, and placental dye injection is extremely helpful to reach the correct diagnosis and establish the optimal management.

Perinatal outcomes of pregnancies with twin-anemia polycythemia sequence complicating twin-to-twin transfusion syndrome using different twin-anemia polycythemia sequence diagnostic criteria

OBJECTIVE

To investigate whether the presence of twin-anemia polycythemia sequence (TAPS) with twin-to-twin transfusion syndrome (TTTS) or post-laser TAPS would change outcomes using different TAPS diagnostic criteria.

METHODS

TTTS cases undergoing laser surgery between 2012 and 2020 were included. Groups included pre-laser TTTS-only compared to TTTS + TAPS, and no post-laser TAPS compared to post-laser TAPS. Three prenatal TAPS diagnostic criteria were used: group A: middle cerebral artery-peak systolic velocity (MCA-PSV) > 1.5 MoM in one twin and <1 MoM in the other twin, group B: inter-twin MCA-PSV difference >1 MoM, and group C: inter-twin MCA-PSV difference >0.5 MoM. Perinatal outcomes including survival and severe cerebral injury were investigated.

RESULTS

174 laser procedures were included. TTTS + TAPS cases were 16 in group A, 17 in group B, and 29 in group C. Post-laser TAPS cases were 11 in group A, 6 in group B, and 12 in group C. There were no differences in preoperative, operative variables and outcomes including survival and severe cerebral injury between groups using all three TAPS diagnostic criteria. The incidence of TTTS + TAPS was highest in group C (16.7%), then group B (9.8%), followed by group A (9.2%). The incidence of post-laser TAPS was highest in group C (9%), then group A (8.3%), followed by group B (4.5%).

CONCLUSION

Presence of TAPS complicating TTTS and presence of post-laser TAPS do not seem to be associated with worse perinatal outcomes including postnatal-ultrasound detected cerebral injury using three different TAPS criteria. Collaborative studies are needed to investigate the validity and the performance of different TAPS criteria.

Management of atypical cases of twin-to-twin transfusion syndrome

Up to 20% of monochorionic diamniotic twin pregnancies can be complicated with twin-to-twin transfusion syndrome (TTTS). This complication is diagnosed by ultrasound demonstrating amniotic fluid discordance between both amniotic sacs, with polyhydramnios in the recipient's sac and oligohydramnios in the donor's, secondary to an imbalance in blood volume exchange between twins. Ultrasound evaluation of the amniotic fluid volume, bladder filling, and assessment of fetal Doppler parameters provide the basis for classification of TTTS, allowing severity assessment. The Quintero's staging system provides a standardized prenatal estimate on the risk of intrauterine fetal demise of one or both twins and the need for fetoscopic laser coagulation of placental vascular anastomoses or delivery depending on the gestational age. However, a proportion of TTTS cases may present without a linear progressive deterioration and no ultrasound signs of preceding staging, in rare situations, they arise even without amniotic fluid discordance. Thus, these unusual clinical presentations of TTTS have long been grouped into the category of atypical TTTS. In this review, we show the clues for diagnosis and management of different atypical cases of TTTS highlighting their underlying mechanism to improve the clinical understanding of such atypical situations, avoid misdiagnosis of TTTS, and allow a timely referral to a fetoscopic center.

Pathophysiology, diagnosis, and management of twin anemia polycythemia sequence in monochorionic multiple gestations

Twin anemia polycythemia sequence (TAPS) is a consequence of unequal sharing of red blood cells between monochorionic twins resulting in anemia in the donor and polycythemia in the recipient twin. Prenatally TAPS can occur spontaneously or complicate incomplete laser surgery for twin transfusion syndrome. While there may be clinical overlap with twin transfusion syndrome or selective fetal growth restriction, diagnosis relies on Doppler measurement of middle cerebral artery peak systolic velocities. Significantly discordant velocities are diagnostic, while severity staging is based on signs of cardiovascular compromise. Conservative management, fetoscopic laser coagulation, selective twin reduction, fetal blood and exchange transfusion, and delivery may be selected guided by the gestational age of diagnosis, the severity of the condition, the likelihood of success, and the patients' priorities. Prenatal curative treatment that minimizes the risk for prematurity and residual morbidity at birth is most likely to offer the greatest short-term and long-term benefits.

Doppler ultrasound in pregnancy - quality requirements of DEGUM and clinical application (part 2)

This second part on Doppler sonography in prenatal medicine and obstetrics reviews its clinical applications. While this has not become the initially anticipated screening tool, it is used for the diagnosis and surveillance of a variety of fetal pathologies. For example, the sonography-based determination of uterine artery blood flow indices is an important parameter for the first trimester multimodal preeclampsia risk assessment, increasing accuracy and providing indication for the prophylactic treatment with aspirin. It also has significant implications for the diagnosis and surveillance of growth-restricted fetuses in the second and third trimesters through Doppler-sonographic analysis of umbilical artery, middle cerebral artery and ductus venosus. Here, especially the hemodynamics of the ductus venosus provides a critical criterium for birth management of severe, early-onset FGR before 34 + 0 weeks of gestation. Further, determination of maximum blood flow velocity of the middle cerebral artery is a central parameter in fetal diagnosis of anemia which has been significantly improved by this analysis. However, it is important to note that the mentioned improvements can only be achieved through highest methodological quality. Importantly, all these analyses are also applied to twins and higher order multiples. Here, for the differential diagnosis of specific complications such as TTTS, TAPS and TRAP, the application of Doppler sonography has become indispensable. To conclude, the successful application of Doppler sonography requires both exact methodology and precise pathophysiological interpretation of the data.

Twin-twin transfusion syndrome with anemia-polycythemia developed during the third trimester of pregnancy

We present here a rare case of twin-twin transfusion syndrome with anemia-polycythemia developed at 34-35 weeks of gestation.

Middle Cerebral Artery Doppler Velocimetry for the Diagnosis of Twin Anemia Polycythemia Sequence: A Systematic Review

Twin anemia polycythemia sequence (TAPS) is a rare complication of monochorionic diamniotic (MCDA) twins. Middle cerebral artery peak systolic velocity (MCA-PSV) measurements are used to screen for TAPS while fetal or neonatal hemoglobin levels are required for definitive diagnosis. We sought to perform a systematic review of the efficacy of MCA-PSV in diagnosing TAPS. Search criteria were developed using relevant terms to query the Pubmed, Embase, and SCOPUS electronic databases. Publications reporting diagnostic characteristics of MCA-PSV measurements (i.e., sensitivity, specificity or receiver operator curves) were included. Each article was assessed for bias using the Quality Assessment of Diagnostic Accuracy Studies II (QUADAS II) tool. Results were assessed for uniformity to determine whether meta-analysis was feasible. Data were presented in tabular form. Among publications, five met the inclusion criteria. QUADAS II analysis revealed that four of the publications were highly likely to have bias in multiple areas. Meta-analysis was precluded by non-uniformity between definitions of TAPS by MCA-PSV and neonatal or fetal hemoglobin levels. High-quality prospective studies with consistent definitions and ultrasound surveillance protocols are still required to determine the efficacy of MCA-PSV in diagnosing TAPS. Other ultrasound findings (e.g., placenta echogenicity discordance) may augment Doppler studies.

Twin-Twin Transfusion Syndrome with Anemia-Polycythemia: Prevalence, Characteristics, and Outcome

The aim of this study was to estimate the prevalence of co-existing anemia-polycythemia (AP) in twin pregnancies with twin-twin transfusion syndrome (TTTS) prior to laser surgery, and to evaluate the characteristics and outcomes in TTTS twins with and without AP. All TTTS cases treated with laser between 2001 and 2019 were retrospectively reviewed for the presence of AP before surgery. AP was defined as delta middle cerebral artery–peak systolic velocity > 0.5 multiples of the median. The primary outcome was a composite of perinatal survival and severe neurodevelopmental impairment (NDI). Secondary outcomes included procedure-related characteristics, severe neonatal morbidity, and disease-free survival. In total, 66% (461/696) of TTTS twin pregnancies were eligible for analysis. AP was detected in 15% (70/461) of the TTTS twins prior to laser surgery. Gestational age at laser was higher in the TTTS+AP group compared to the TTTS-only group—21.0 weeks (interquartile rage (IQR): 18.8–24.0) versus 19.3 weeks (IQR: 17.3–21.9), respectively (p < 0.0001). Fewer placental anastomoses were detected in the TTTS+AP group than in the TTTS-only group—five (IQR: 4–6) versus six (IQR: 5–8), respectively (p < 0.0001). Perinatal survival was 77% (599/782) in the TTTS-only group and 83% (118/142) in the TTTS+AP group (p = 0.130). Severe NDI was 8% (28/370) in TTTS-only and 3% (2/74) in TTTS+AP. TTTS-only twins showed more severe neonatal morbidity than twins with TTTS+AP—23% (132/575) versus 11% (13/115), respectively (p = 0.005). Disease-free survival was lower in the TTTS-only group compared to the TTTS+AP group—62% (341/548) versus 73% (72/98), respectively (p = 0.046). Thus, AP complicates 15% of TTTS twins prior to laser. TTTS+AP twins show a different placental angioarchitecture, a later time of onset of the disease, and a more favorable outcome.

The value of echocardiography and Doppler in the prediction of fetal demise after laser coagulation for TTTS: A systematic review and meta-analysis

This study aimed to investigate the value of echocardiography and Doppler before fetoscopic laser coagulation for twin‐twin transfusion syndrome (TTTS) in the prediction of intrauterine fetal demise (IUFD). We performed a systematic review and meta‐analysis to compare preoperative parameters between fetuses with and without demise after laser surgery. Eighteen studies were included. Recipient twins have an increased risk of demise in case of preoperative absent/reversed flow (A/REDF) in the umbilical artery (odds ratio [OR] 2.76, 95% confidence interval [CI], 1.78‐4.28), absent or reversed a‐wave in the ductus venosus (OR 2.32, 95% CI, 1.70‐3.16), or a middle cerebral artery peak systolic velocity > 1.5 multiples of the median (MoM) (OR 7.59, 95% CI, 2.56‐22.46). In donors, only A/REDF in the umbilical artery (OR 3.40, 95% CI, 2.68‐4.32) and absent or reversed a‐wave in the ductus venosus (OR 1.66, 95% CI, 1.12‐2.47) were associated with IUFD. No association was found between donor‐IUFD and preoperative myocardial performance index (MPI). Two studies found an association between abnormal MPI and recipient demise. With this study, we have identified a set of preoperative Doppler parameters predictive of fetal demise after laser surgery. More research is needed to assess the utility of preoperative echocardiographic parameters such as the MPI in predicting IUFD.

What's already known about this topic?

Doppler parameters are associated with fetal demise after laser surgery.

Echocardiographic parameters are currently not used in risk stratification.

What does this study add?

A more extensive set of preoperative Doppler parameters is defined to predict post‐laser fetal demise.

The utility of preoperative echocardiographic parameters such as the MPI in predicting fetal demise remains unclear.

Quantified discordant placental echogenicity in twin anemia-polycythemia sequence (TAPS) and middle cerebral artery peak systolic velocity

OBJECTIVE

To quantify sonographic placental echogenicity in twin anemia-polycythemia sequence (TAPS) and to correlate it with middle cerebral artery peak systolic velocity (MCA-PSV) measurements.

METHODS

We performed a retrospective search for consecutive TAPS cases between 16 and 36 weeks of gestation (MCA-PSV > 1.5 multiples of the median (MoM) in the anemic donor and < 1.0 MoM in the polycythemic recipient) in our database of monochorionic twin gestations from January 2007 until December 2016. In cases for which ultrasound images showing the donor's and the recipient's part of the placenta were available, echogenicity for both twins was quantified by image processing. MCA-PSV Doppler values of both fetuses were correlated to their respective placental echogenicity. Placental thickness of both twins was also measured.

RESULTS

Of 756 cases with MCA-PSV measurements identified from the database, 36 (4.8%) had TAPS; of these, 23 had TAPS combined with twin-twin transfusion syndrome and 13 showed isolated TAPS. Placental echogenicity could be quantified in 28 pregnancies. Mean ± SD placental echogenicity of donor twins was significantly higher than that of recipients (138.7 ± 22.8 vs 77.9 ± 37.0; P < 0.0001). Furthermore, a significant positive correlation was found between placental echogenicity and MCA-PSV MoM (R = 0.67, P < 0.0001). Mean placental thickness of donor twins (n = 20) was significantly higher than that of recipients (49.3 mm ± 13.4 vs 25.4 mm ± 10.1; P < 0.0001).

CONCLUSIONS

Echogenicity of the placental share in recipient and donor twins with TAPS correlates with MCA-PSV values. Quantification of sonographic placental echogenicity may help to determine the severity of TAPS in monochorionic twins. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Twin Anemia Polycythemia Sequence: Current Views on Pathogenesis, Diagnostic Criteria, Perinatal Management, and Outcome

Monochorionic twins share a single placenta and are connected with each other through vascular anastomoses. Unbalanced inter-twin blood transfusion may lead to various complications, including twin-to-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS). TAPS was first described less than a decade ago, and the pathogenesis of TAPS results from slow blood transfusion from donor to recipient through a few minuscule vascular anastomoses. This gradually leads to anemia in the donor and polycythemia in the recipient, in the absence of twin oligo-polyhydramnios sequence (TOPS). TAPS may occur spontaneously in 3-5% of monochorionic twins or after laser surgery for TTTS. The prevalence of post-laser TAPS varies from 2% to 16% of TTTS cases, depending on the rate of residual anastomoses. Pre-natal diagnosis of TAPS is currently based on discordant measurements of the middle cerebral artery peak systolic velocity (MCA-PSV; >1.5 multiples of the median [MoM] in donors and 8 g/dL), and at least one of the following: reticulocyte count ratio >1.7 or minuscule placental anastomoses. Management includes expectant management, and intra-uterine blood transfusion (IUT) with or without partial exchange transfusion (PET) or fetoscopic laser surgery. Post-laser TAPS can be prevented by using the Solomon laser surgery technique. Short-term neonatal outcome ranges from isolated inter-twin Hb differences to severe neonatal morbidity and neonatal death. Long-term neonatal outcome in post-laser TAPS is comparable with long-term outcome after treated TTTS. This review summarizes the current knowledge after 10 years of research on the pathogenesis, diagnosis, management, and outcome in TAPS.

Does anemia-polycythemia complicating twin-twin transfusion syndrome affect outcome after fetoscopic laser surgery?

OBJECTIVE

Twin anemia-polycythemia sequence (TAPS) can occur as a unique disease or as a complication of twin-twin transfusion syndrome (TTTS). Middle cerebral artery (MCA) Doppler studies are not currently part of the routine evaluation of monochorionic twins since they are not used in the Quintero staging system. As such, the true incidence of TAPS is unknown. We aimed to compare the characteristics and outcomes of twin pregnancies with TTTS complicated by spontaneous anemia-polycythemia vs those with TTTS alone.

METHODS

This was a secondary analysis of data collected prospectively from a cohort of 156 consecutive patients undergoing fetoscopic laser surgery for TTTS, between October 2011 and August 2014. TAPS was defined as discordance in the preoperative MCA peak systolic velocity (PSV), with one twin fetus having MCA-PSV ≤ 1.0 multiples of the median (MoM) and the other having MCA-PSV ≥ 1.5 MoM. Maternal demographics as well as preoperative, operative and postoperative variables were analyzed.

RESULTS

Included in the final analysis were 133 patients with complete records: 11 cases with TTTS with anemia-polycythemia and 122 cases with TTTS alone. There was no difference in maternal body mass index, gestational age (GA) at procedure, rate of preterm prelabor rupture of membranes or GA at delivery between the two groups. Patients with TTTS and anemia-polycythemia were more likely to be older (P = 0.03) and parous (P = 0.04) and had a significantly lower number of placental anastomoses (P = 0.01). The dual live-birth rate was similar for both groups (P = 0.76).

CONCLUSION

Cases of TTTS with anemia-polycythemia were more likely to be found in parous and older women and were characterized by fewer vascular anastomoses. TTTS with anemia-polycythemia was not associated with worse perinatal outcome after laser therapy. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Anomalies of the placenta and umbilical cord in twin gestations

The frequency of twin gestations has increased over the last few decades, mainly due to maternal age at childbearing, and the use of assisted reproductive technologies. Twins are at higher risk of aneuploidy, structural anomalies, and placental abnormalities. Some of the placental and umbilical cord abnormalities found in twin gestations are nonspecific and can be found in singleton gestations (ie, placenta previa, placental abruption, single umbilical artery, velamentous cord insertion, vasa previa, etc). However, other anomalies are unique to twin gestations, and are mainly associated with monochorionic twins-these include intraplacental anastomosis and cord entanglement. Most of these conditions can be diagnosed with ultrasound. An accurate and early diagnosis is important in the management of twin gestations. Determination of chorionicity, amnionicity, and the identification of placental anomalies are key issues for the adequate management of twin pregnancies. Pathologic placental examination after delivery can help in assessing the presence of placental and umbilical cord abnormalities, as well as providing information about chorionicity and gaining insight into the potential mechanisms of disease affecting twin gestations.