Intrafetal radiofrequency ablation for twin reversed arterial perfusion (TRAP): a single-center experience

Management of twin reversed arterial perfusion (TRAP) sequence with microwave ablation: A case report and review of the literature

Twin reversed arterial perfusion (TRAP) sequence carries a high mortality risk to the "pump twin." Management involves disrupting blood flow to the acardiac mass. In this case, the pregnant patient presented at 20 weeks 6 days with Stage IIb TRAP Sequence and underwent percutaneous ultrasound-guided microwave ablation (MWA) of the acardiac mass at 21 weeks 0 days. The probe traversed the thorax of the acardiac mass and ablated the confluence of the umbilical vessels. A healthy child was delivered at 33 weeks 5 days gestation. This report demonstrates the utility of MWA in TRAP sequence and describes a novel approach.

Fetal magnetic resonance imaging, ultrasound, and echocardiography findings in twin reversed arterial perfusion sequence

BACKGROUND

Twin reversed arterial perfusion (TRAP) sequence is a rare complication of monochorionic multiple gestation pregnancies, in which the pump twin provides hemodynamic support to a nonviable co-twin (acardius). Fetal magnetic resonance imaging (MRI) is used to detect pump twin abnormalities, particularly brain ischemia, prior to fetal intervention to interrupt umbilical blood flow to the acardius.

OBJECTIVE

To summarize the imaging findings of TRAP sequence pregnancies in a large series.

MATERIALS AND METHODS

A single-center retrospective review was performed of all TRAP sequence pregnancies referred for fetal MRI (2004-2021). Fetal MRI, ultrasound, and echocardiography data were collected.

RESULTS

Eighty-eight TRAP sequence pregnancies with MRI were included (mean gestational age, 19.8±2.8 weeks). Demise of the pump twin was noted in two pregnancies at the time of MRI. By MRI, 12% (10/86) of live pump twins had abnormalities, including 3% (3/86) with brain abnormalities and 9% (8/86) with extra-cranial abnormalities. By echocardiography, 7% (6/86) of pump twins had structural cardiac abnormalities. Three acardius morphological subtypes were identified by MRI: acephalus (55%, 48/88), anceps (39%, 34/88), and amorphous (7%, 6/88). The mean ultrasound acardius to pump twin ratio A/P ratio, calculated for each twin pair as the ratio of the acardius trunk (and head, if present) plus limb volume to the pump twin estimated fetal weight) differed among the three acardius subtypes (P=.03). The mean A/P ratio moderately correlated with pump twin cardiothoracic ratio and combined cardiac output (Pearson's r=0.45 and 0.48, respectively, both P<.001).

CONCLUSION

Fetal MRI of TRAP sequence pregnancies found anomalies in a substantial number of pump twins. The three acardius subtypes differed in A/P ratio, which moderately correlated with the pump twin cardiothoracic ratio and combined cardiac output.

"The Strange Case of Dr Pump and Mr Acardiac": The Twin Reversed Arterial Perfusion (TRAP) Sequence in Two Monochorionic Monoamniotic (MCMA) Twin Pregnancies-Diagnosis, Prognosis and Management: Review of Literature

The Twin Reversed Arterial Perfusion (TRAP) Sequence is an extremely rare complication of monochorionic twin pregnancies, with one severely malformed twin (the "acardiac") lacking autonomous placental blood supply and being perfused by the co-twin (the "pump"), through arterio-arterial (and sometimes also veno-venous) vascular anastomoses located on the placental surface. The prognosis is poor: mortality is 100% in the acardiac twin because of its severe malformations and about 50-55% in the pump twin, mainly due to heart failure and prematurity. So, the goal of perinatal management of the TRAP twin pregnancy is to deliver a healthy and near-term pump twin without heart failure or fetal hydrops. Intuitively, the earlier the diagnosis, the better the outcome. Herein, we report two cases of monochorionic monoamniotic (MCMA) twin pregnancies complicated by the TRAP Sequence, which are of interest since the objective of early diagnosis was achieved by means of transvaginal and 3D ultrasound, two techniques which revealed themselves as being useful to this purpose but are underused in the literature. The second aim of this study is to provide an overview of literature data about the diagnosis, prognosis establishment, and management of this rare condition, which are still debated and unclear due to negligible poor-quality evidence.

Twin reversed arterial perfusion (TRAP) sequence: A case report and a brief literature review

Twin reversed arterial perfusion (TRAP) sequence is rare in monochorionic twin pregnancies. TRAP sequence is distinct from other multifetal pregnancies in that one of the twins has normal anatomy while the other twin has a varied amount of characteristic abnormal features. In the literature, mortality is reported 100% in the abnormal twin. We report 1 case of TRAP sequence at our institution in which the diagnosis of TRAP sequence was missed in the first trimester at another hospital. The patient, a 33-year-old G1P0A0, did not have any follow-up after her first scan until the routine second-trimester ultrasound at our institution. Both the radiologist and the sonographer did not appreciate the differential diagnosis of TRAP sequence in their clinical decision-making. The TRAP diagnosis was established after the ultrasound performed at the fetal assessment unit in our hospital. Radiofrequency ablation (RFA) procedure was performed to give the normal twin a chance to survive, but unfortunately, the prognosis was poor in this case. We conclude that diagnosing a TRAP sequence is very important early in the pregnancy for a positive outcome in the normal twin. A robust collaboration among radiologists and obstetricians is vital for the best outcome of the normal twin.

Twin reverse arterial perfusion: Timing of intervention

Twin reverse arterial perfusion (TRAP) sequence is a severe anomaly in monochorionic twins where one twin has profound corporeal underdevelopment and acardia. The normal "pump" co-twin provides blood flow to the acardiac twin through placental anastomoses which may lead to cardiac failure and pump twin demise as well as preterm delivery from severe polyhydramnios. Treatments include radiofrequency ablation, bipolar cord coagulation, and intrafetal laser with each aimed at occluding blood flow to the acardiac twin. However, none of these modalities has proven superior in terms of either pump twin survival or minimization of complications, including preterm premature rupture of membranes, preterm birth, or unexpected co-twin demise. The optimal timing of treatment is also unknown, without clear indications for intervention versus expectant management. Very early treatment of TRAP (i.e., <16 weeks) has been proposed to reduce first-trimester demise; however, this approach remains experimental. Further investigation is required to determine the best treatment and timing of intervention for TRAP.

Twin reversed arterial perfusion sequence managed by bipolar cord coagulation and amniopatch: Case report

Introduction and importance

Twin Reversed Arterial Perfusion (TRAP) Sequence is a rare condition that occurs in monochorionic twin pregnancies, resulting in the coexistence of a normal “pump” twin and an acardiac twin. Indonesia is implementing fetal therapy centers that are starting to treat fetal cases such as TRAP Sequence.

Case presentation

An 18 years old pregnant woman with monochorionic diamniotic pregnancy was detected by ultrasonographic examination. A live fetus with normal fetal heart rate estimated fetal weight was 661 g, and consistent with 25 w gestational age. Additionally, an acardiac twin with polyhydramnios and EFW of 1829 g. Bipolar cord coagulation, amniopatch, and amnioinfusion were performed. The patient's condition was stable and managed closely.

Clinical discussion

This is the first procedure reported in Indonesia for TRAP sequence case. It reduces cardiac strain on the pump twin and increases the chance of survival.

Conclusion

The patient was diagnosed with TRAP Sequence and bipolar cord coagulation to interrupt blood supply to the non-viable twin, amniopatch with autologous platelet concentrate followed by cryoprecipitate amnioinfusion were reported for the first time in Indonesia.

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The first case of bipolar cord coagulation and amniopatch in the TRAP sequence was reported in Indonesia.

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The first case report in Indonesia informs the success in the management of TRAP Sequence.

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Increase the survival of infant

Perinatal outcomes after selective feticide via umbilical cord occlusion in complicated monochorionic pregnancies: A systematic review and meta-analysis

OBJECTIVE

We aimed to compare perinatal outcomes between umbilical cord occlusion techniques in monochorionic pregnancies, including umbilical cord ligation, fetoscopic laser coagulation, interstitial laser coagulation, bipolar cord occlusion, radiofrequency ablation, and microwave ablation.

METHODS

This study was registered with PROSPERO (CRD42020158861). PubMed, Web of Science, Cochrane Library, and Embase were searched for studies published up to May 2020. The DerSimonian-Laird random-effects model was used for the meta-analysis. Subgroup analyses were performed to compare the outcomes among the six techniques. Meta-regression was used to adjust for confounders.

RESULTS

Thirty-four studies with 1646 participants were included. The overall survival was 76.5% after umbilical cord ligation, 78.8% after fetoscopic laser coagulation, 60.3% after interstitial laser coagulation, 79.2% after bipolar cord occlusion, 77.5% after radiofrequency ablation, and 75.0% after microwave ablation. Subgroup comparison showed the rates of overall survival and preterm premature rupture of membranes were not significant different among six techniques. However, rates of fetal loss, premature birth, live birth, and neonatal death differed significantly among the six groups.

CONCLUSIONS

The choice of umbilical cord occlusion techniques will affect perinatal outcomes. We suggested that the choice of umbilical cord occlusion techniques should fully consider these differences among techniques.

Unique Considerations: Preterm Prelabor Rupture of Membranes in the Setting of Fetal Surgery and Higher Order Pregnancies

Two unique aspects of antenatal care occur in the setting of fetal surgery and multiple gestations. As fetal interventions increase, so do the number of cases of iatrogenic preterm prelabor rupture of membranes (PPROM). Because of the amniotic sac's inability to heal, the risk of PPROM after surgery is directly correlated with the number of interventions, the size of the defect, and the surgery performed. Higher order gestations also carry an increased risk of PPROM. This paper reviews the risks and management of PPROM in the setting of the various prenatal interventions as well as in the setting of multiple gestations.

Microwave ablation versus radiofrequency ablation for the treatment of severe complicated monochorionic pregnancies in China：protocol for a pilot randomised controlled trial

INTRODUCTION

Complicated monochorionic twin pregnancies are often associated with high perinatal morbidity and mortality, some of which are severe enough to require a gestational reduction surgery to improve fetal survival and reduce disabilities. While radiofrequency ablation is currently the most commonly used procedure with higher fetal survival and fewer maternal and fetal complications compared with other surgical methods, the therapeutic effect of microwave ablation (MWA) is reported to be better, presumably due to the higher thermal effect and fewer restrictions. Currently there is limited evidence to prove the feasibility of MWA for selective reduction. The aim of this pilot study is to explore the feasibility, efficacy and safety of MWA reduction for severe complicated monochorionic pregnancies and may provide evidence for using the MWA in intrauterine surgeries extensively.

METHODS AND ANALYSIS

This is a study protocol for a parallel-design pilot randomised controlled trial. 60 eligible patients with severe complicated monochorionic pregnancies will be randomised in a ratio of 1:1 to MWA group and radiofrequency group. Patients will be followed up until 6 months of age of the retained fetal. The primary analysis will compare the rates of neonatal survival at 28 days to evaluate the effect of MWA. The study will also evaluate the safety profile of MWA including the occurrence of postoperative adverse events and maternal and fetal complications. Additional secondary outcomes to be explored include the condition of neonatal asphyxia and the growth of surviving fetus at 6 months. Outcomes will be analysed by both a frequentist and the Bayesian statistical approach.

ETHICS AND DISSEMINATION

This study was approved by the ethical review committee of the Peking University Third Hospital (Beijing, China). The results of this study will be published in peer-reviewed scientific journals and presented at relevant academic conferences.

TRIAL REGISTRATION NUMBER

NCT04014452; Pre-results.

Risk Factors for Co-Twin Fetal Demise following Radiofrequency Ablation in Multifetal Monochorionic Gestations

BACKGROUND

Umbilical cord occlusion via radiofrequency ablation (RFA) is utilized to maximize outcomes of the co-twin in complicated multifetal monochorionic (MC) gestations. However, post-procedure co-twin fetal demise is of concern.

OBJECTIVE

The aim of this study was to determine risk factors for co-twin fetal demise following RFA.

METHODS

This is a retrospective study of MC multiples that underwent RFA. Indications for RFA included twin reversed arterial perfusion (TRAP) sequence, selective fetal growth restriction (sFGR) type II, discordant lethal anomalies, and twin-twin transfusion syndrome (TTTS) with proximate placental cord insertion sites. The primary outcome was co-twin fetal demise. Bivariate analyses and multiple logistic regression modeling of identified risk factors were conducted.

RESULTS

Of 36 patients studied, surgical indications were: TRAP (n = 15, 41.7%), sFGR (n = 10, 27.8%), discordant anomalies (n = 9, 25.0%), and TTTS (n = 2, 5.6%). Nine patients (25.0%) experienced a co-twin fetal demise. In multiple logistic regression analysis, fetal growth restriction (FGR) of one co-twin was associated with increased risk of co-twin fetal demise (OR = 10.85, 95% CI 1.03-114.48, p = 0.0474) and a preoperative diagnosis of TRAP was protective against fetal demise (OR = 0.06, 95% CI 0.00-0.84, p = 0.0368).

CONCLUSION

Co-twin FGR was associated with an increased risk of post-RFA demise. When compared to other indications, patients with TRAP sequence were less likely to have a co-twin demise.

First-trimester intervention in twin reversed arterial perfusion sequence

OBJECTIVE

To report the outcome of monochorionic twins with twin reversed arterial perfusion (TRAP) sequence following interstitial laser therapy in the first trimester.

METHODS

This was a retrospective cohort study of all consecutive cases of TRAP that underwent interstitial laser therapy at ≤ 14 + 3 weeks' gestation between January 2014 and April 2016. Interstitial laser treatment was performed under ultrasound guidance using a 400-nm Nd:YAG laser fiber. Hospital records were reviewed to ascertain perinatal survival and morbidity.

RESULTS

Twelve monochorionic twin pregnancies underwent interstitial laser treatment of the umbilical artery of the acardiac fetus, at a median gestational age of 13 + 5 (interquartile range (IQR), 13 + 4 to 14 + 0) weeks. In all cases, one treatment was sufficient to achieve complete interruption of the perfusion of the acardiac twin. There were no procedure-related complications during or within 48 h after the procedure. In one (8.3%) case, intrauterine death of the pump twin occurred 2 weeks after the intervention. All other cases (91.7%) resulted in a live birth at a median gestational age of 39 + 6 (IQR, 37 + 1 to 41 + 2) weeks and with a median birth weight of 3370 (IQR, 2980-3480) g. No neonatal mortality or serious morbidity occurred.

CONCLUSIONS

Our results support the use of interstitial laser therapy in the first trimester of pregnancy complicated by TRAP sequence, showing a live birth rate of 92%. The results of a randomized controlled trial, evaluating early vs late intervention in pregnancy with TRAP sequence, are awaited. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Treatment of twin-reversed arterial perfusion sequence using high-intensity focused ultrasound

We describe our experience of high-intensity focused ultrasound (HIFU) for fetal therapy in twin-reversed arterial perfusion (TRAP) sequence. Six pregnant women underwent HIFU therapy, five before 16 weeks and one at 26 weeks. Two types of HIFU system were used: the first-generation system, which comprised a biaxial transducer and continuous exposure pattern, and the second-generation system, which comprised a coaxial transducer and sequential exposure pattern. The first-generation apparatus was used in four cases and the second-generation apparatus was used in two. In three cases, occlusion of the blood vessels mediating flow to the acardiac twin was achieved by HIFU. Two cases experienced intrauterine fetal death despite vessel occlusion. The total survival rate of pump fetuses 2 years after HIFU was 67% and the efficiency rate (the proportion of cases with occlusion or reduced blood flow on ultrasound after HIFU) was 83%. After more than 2 years of follow-up, the surviving infants had no severe clinical complications and no postnatal developmental problems. There was no significant difference in survival rate compared with TRAP cases managed expectantly. Given that complete occlusion of the blood vessels was not achieved in half of the cases, we could not show that HIFU therapy is superior to other treatments. However, HIFU can reduce the cardiac load of the pump fetus and, as it does not require uterine puncture for fetal therapy, there were no fatal complications, such as bleeding, rupture of membranes or infection. Thus, HIFU therapy may represent a less-invasive treatment for TRAP sequence in early pregnancy. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Twin Reversed Arterial Perfusion Sequence: Assessing the Role of the Correct Imaging Modality in a Rare Clinical Entity

Acardiac twin formation is a rare anomaly. It is one of the most extreme complications of monozygotic twin pregnancies. Such occurrences are brought about when a normal twin donates blood to an abnormal twin through its umbilical arteries via vascular anastomoses at the level of the placenta, which is termed as twin reversed arterial perfusion sequence (TRAPS). Twin reversed arterial perfusion sequence is considered a rare variant of twin-to-twin transfusion syndrome. Due to the considerable blood transfer from the healthy twin to the parasitic one, cardiac failure can ensue in the healthy twin. The mortality of the acardiac twin is 100%. We present an obstetric case of a South Asian female, whose serial ultrasound scans consistently displayed a heterogeneous mass, initially labeled a teratoma. This was postoperatively diagnosed as an acardiac twin due to TRAPS. Thus, we would like to highlight the importance of umbilical artery Doppler in the prompt diagnosis of TRAPS so timely management may be undertaken to prevent morbidity and/or mortality of the normal twin.

Use of the Tei Index in the Conservative Management of TRAP Sequence Pregnancies Diagnosed during the Periviable Period: A Case Series

Twin Reverse Arterial Perfusion (TRAP) Sequence is a rare complication of monochorionic pregnancies. Without intervention, the viable pump twin in a case of TRAP Sequence may develop high output cardiac failure leading to an intrauterine fetal demise. We present 3 cases of TRAP Sequence pregnancy diagnosed during the second or third trimesters of pregnancy. There are minimal sonographic tools for the guidance of a fetal therapeutic interventional procedure during the second trimester or timing of delivery during the third trimester to reduce morbidity and mortality of a viable fetus. Tei index may be a useful sonographic tool in the management of TRAP Sequence during the second or third trimester of pregnancy.

Uncommon complications of monochorionic twin pregnancies: Twin reversed arterial perfusion sequence

Introduction

Twin reversed arterial perfusion (TRAP) sequence occurs when there is one non-viable twin without cardiac structures and a viable pump twin that perfuses the acardiac mass. This study aims to investigate the management and immediate neonatal outcomes for monochorionic multiple pregnancies complicated by TRAP referred to the NSW Fetal Therapy Centre (NSW FTC).

Methods

Retrospective cohort study of multiple pregnancies referred to NSW FTC between April 2006 and April 2014, reviewing data for cases of TRAP sequence (n = 19, including two triplet cases) compared to a timeframe matched sample of uncomplicated monochorionic diamniotic (MCDA) twin pregnancies managed in the unit (n = 45).

Results

Primary management of the 19 TRAP cases was expectant management in 10 (53%), radiofrequency ablation (RFA) in 6 (32%), and bipolar cord coagulation, amniodrainage and termination of pregnancy in 1 case each. 1 of 6 RFA cases had pump twin demise <1 week post-procedure. Average gestation at birth (35.1 ± 5.0 vs. 35.0 ± 2.8 weeks) and mean birthweight (2157 ± 1019 g vs. 2245 ± 537 g) were similar between TRAP pump fetuses and uncomplicated MCDA cases. Pump twin survival was 81% (twins only) compared to 98% for uncomplicated MCDA twins (P = 0.02), and in 5 of 19 (26%) TRAP pregnancies the pump fetus had a congenital anomaly.

Conclusion

Mean gestational age at birth and mean birthweight were similar for both TRAP and uncomplicated MCDA pregnancies. TRAP cases, however, had higher perinatal mortality, and high rates of congenital anomaly. The overall neonatal outcome at NSW FTC for TRAP cases is similar to reported international outcomes.

Basic study of less invasive high-intensity focused ultrasound (HIFU) in fetal therapy for twin reversed arterial perfusion (TRAP) sequence

PURPOSE

The objective of the present study was to develop a high-intensity focused ultrasound (HIFU) transducer more suitable for clinical use in fetal therapy for twin reversed arterial perfusion (TRAP) sequence.

MATERIALS AND METHODS

We created a cooling and degassed water-circulating-type HIFU treatment device. HIFU was applied to renal branch vessels in three rabbits. Sequential HIFU irradiation contains a trigger wave, heating wave, and rest time. The duration of HIFU application was 10 s/course. Targeting could be achieved by setting the imaging probe in the center and placing the HIFU beam and imaging ultrasonic wave on the same axis.

RESULT

We confirmed under sequential HIFU irradiation with a total intensity of 1.94 kW/cm(2) (spatial average temporal average intensity) that the vein and artery were occluded in all three rabbits.

CONCLUSION

Simultaneous occluding of the veins and arteries was confirmed with trigger waves and a resting phase using the HIFU transducer treatment device created for this study. Clinical application appears possible and may represent a promising option for fetal therapy involving TRAP sequence.

Clinical Outcomes after Selective Fetal Reduction of Complicated Monochorionic Twins with Radiofrequency Ablation and Bipolar Cord Coagulation

AIMS

To review pregnancy outcomes, complication rates and neonatal neural development of selective termination procedures for complicated monochorionic (MC) twins.

METHODS

This was a retrospective review of the pregnancies that underwent selective reduction with radiofrequency ablation (RFA) and bipolar cord coagulation (BCC) in our institution.

RESULTS

Forty-eight cases underwent selective reduction with BCC and the remaining 45 with RFA. Overall survival was not statistically different between the RFA and BCC groups (71.1 and 62.5%, p = 0.379). With regard to the indications, the survival rates were not significantly different for twin to twin transfusion syndrome, twin reversed arterial perfusion, discordant anomalies and selective intrauterine growth restriction. Preterm premature rupture of membrane was not statistically different between the BCC and RFA groups (47.9 and 33.3%, p = 0.153). Five foetuses presented with abnormal middle cerebral artery-peak systolic velocity in the BCC group and 4 in the RFA group (p = 0.829). In the BCC group, neurological injury was detected in 2 neonates, presenting with cerebral dysplasia on MR scanning. In the RFA group, intracranial haemorrhage Grade III was detected in one neonate with cranial ultrasound (p = 0.607).

CONCLUSIONS

Overall survival and complication rates following selective reduction in complicated MC twin pregnancies is similar irrespective of whether the reduction was performed using RFA or BCC. Key Message: It seems that selective reduction in MC pregnancies with RFA does not carry a significant decrease in the overall survival and complication rates than the cases with BCC. According to our data, neurodevelopmental impairment of the co-twins is relatively seldom after selective reduction.

In-utero radiofrequency ablation in fetal piglets: Lessons learned

INTRODUCTION

Radiofrequency ablation (RFA) is increasingly utilized in minimally invasive fetal intervention. However, the response of different fetal tissues to RFA is poorly characterized. We sought to determine the extent of RFA damage in a fetal environment.

METHODS

90Day gestation Yorkshire piglets (term 115days) were subjected to RFA of the chest and abdominal viscera under various temperatures and wattages. The extent of tissue damage was determined by NADPH diaphorase histochemistry.

RESULTS

Tyne temperature was widely variable and displayed varying responses between lung and liver tissue. Tyne exposure to amniotic fluid resulted in an increase in amniotic fluid temperature. Collateral damage, even across the diaphragm, was readily seen, and ultrasonography did not always reflect this injury.

CONCLUSIONS

Utilization of extracorporeal tynes heats fluid at a greater rate than solid tissue and reliance on temperature sensitive probes may result in overheating. The extent of injury may extend beyond damage observed by ultrasound examination and varies for different tissues. Additional studies on the use of devices that regulate tyne temperature are needed to define optimal conditions and better define the extent of adjacent tissue injury.

Forty cases of twin reversed arterial perfusion sequence treated with radio frequency ablation using the multistep coagulation method: a single-center experience

OBJECTIVE

To report the pregnancy outcomes of patients with twin reversed arterial perfusion (TRAP) sequence treated by radiofrequency ablation (RFA).

METHODS

This was a retrospective study of TRAP sequences treated in a single center between March 2002 and February 2015. Forty patients underwent RFA with expandable tines through a multistep coagulation method between 15 and 26 gestational weeks. The primary outcome was neonatal survival to discharge.

RESULTS

The overall survival of the pump twin was 85%. The survival rates in monochorionic-monoamniotic (MCMA) pregnancies and monochorionic-diamniotic pregnancies were 66.7% (4/6) and 87.9% (29/33), respectively. One triplet was treated successfully and delivered at 36 weeks of gestation. One of 35 live births (2.9%) had preterm premature rupture of membranes less than 34 weeks, resulting in infant death. In five intrauterine pump twin deaths, two cases were MCMA twins with cord entanglement, and three cases were MCDA twins with acardius anceps.

CONCLUSIONS

Our study supports the effectiveness of RFA for TRAP sequence after 15 weeks of gestation. The presence of MCMA twins or acardius anceps is associated with a high risk of pump twin death after RFA. © 2016 John Wiley & Sons, Ltd.

Radiofrequency Ablation with an Internally Cooled Electrode for Twin Reversed Arterial Perfusion Sequence

OBJECTIVE

The study aims to evaluate the efficacy of radiofrequency ablation (RFA) with an internally cooled electrode for twin reversed arterial perfusion (TRAP) sequence.

METHODS

From April 2008 through December 2014, we retrospectively reviewed all patients who underwent RFA with an internally cooled electrode for TRAP sequence at 3 tertiary referral centers in Japan.

RESULTS

Twenty-five monochorionic diamniotic twin pregnancies underwent RFA with an internally cooled electrode for TRAP sequence at 16-27 weeks of gestation. In all cases, umbilical cord blood flow cessation in the acardiac twin was confirmed by ultrasonography with color Doppler. There were 2 cases of procedure-related complications: 1 case of unintentional septostomy and 1 case of anemia in a pump twin. Fetal demise of the pump twin occurred in 3 (12%) cases. Twenty-two (88%) of 25 pump twins were delivered alive. The median gestational age at delivery was 36 + 3 weeks (range 25 + 2-40 + 5 weeks). There were 14 cases (64%) of premature deliveries before 37 weeks and 5 (23%) before 32 weeks.

CONCLUSION

RFA with an internally cooled electrode is a feasible and effective procedure for the treatment of TRAP sequence.

Twin reversed arterial perfusion (TRAP) sequence managed at 11+6 weeks with radiofrequency ablation

Radiofrequency ablation (RFA) has become widely accepted as first-line management for twin reversed arterial perfusion (TRAP) sequence. Most RFA procedures have been performed using RFA needles of 14–17 gauge (G) focusing on an acardiac mass at an average age of 21 weeks of gestation (17–24 weeks). In this case report, we describe treatment of TRAP sequence using RFA with a 20 G needle focusing a feeding artery on the placental surface at gestational age of 11+6.

Minimally invasive fetal therapy for hydropic lung masses: three different approaches and review of the literature

OBJECTIVE

To report three different antenatal therapeutic approaches for fetal lung masses associated with hydrops.

METHODS

Three prospectively followed cases are described, and all 30 previously published minimally invasive cases of fetal therapy for hydropic lung masses are reviewed.

RESULTS

Three hydropic fetuses with large intrathoracic lung masses presented at 17, 25 and 21 weeks of gestation, respectively. An aortic feeding vessel was identified in each case and thus a bronchopulmonary sequestration (BPS) was suspected. Under ultrasound guidance, the feeding vessel was successfully occluded with interstitial laser (Case 1), radiofrequency ablation (RFA) (Case 2) and thrombogenic coil embolization (Case 3). Complete (Cases 1 and 2) or partial (Case 3) resolution of the lung mass and hydrops was observed. A healthy infant was born at term after laser therapy (Case 1), and the involved lung lobe was resected on day 2 of postnatal life. In Case 2, hydrops resolved completely following RFA, but an iatrogenic congenital diaphragmatic hernia and abdominal wall defect became apparent 4 weeks later. The neonate died from sepsis following spontaneous preterm labor at 33 weeks. In Case 3, despite technical success in complete vascular occlusion with coils, a stillbirth ensued 2 days after embolization.

CONCLUSIONS

The prognosis of large microcystic or echogenic fetal chest masses associated with hydrops is dismal. This has prompted attempts at treatment by open fetal surgery, with mixed results, high risk of premature labor and consequences for future pregnancies. We have demonstrated the possibility of improved outcome following ultrasound-guided laser ablation of the systemic arterial supply. Despite technical success, RFA and coil embolization led to procedure-related complications and need further evaluation.

Radiofrequency ablation as a minimally invasive procedure in the treatment of twin reversed arterial perfusion sequence in twin pregnancy

Twin reversed arterial perfusion sequence is a rare anomaly of monochorionic multiple pregnancies affecting 1 of 35,000 pregnancies and 1% of monochorionic twin pregnancies. In this condition the affected twin has lethal malformations including poor or absent heart development and is reversely perfused by a structurally normal co-twin. We report a case of a 21-year-old woman with a monochorionic twin pregnancy affected by twin reversed arterial perfusion sequence. This case highlights the therapeutic options and the management by radiofrequency ablation, which has been shown to be an easy and reliable technique with a high success rate compared with technically demanding fetoscopic procedures.

Ultrasound in twin pregnancies

OBJECTIVE

To review the literature with respect to the use of diagnostic ultrasound in the management of twin pregnancies. To make recommendations for the best use of ultrasound in twin pregnancies.

OUTCOMES

Reduction in perinatal mortality and morbidity and short- and long-term neonatal morbidity in twin pregnancies. Optimization of ultrasound use in twin pregnancies.

EVIDENCE

Published literature was retrieved through searches of PubMed and the Cochrane Library in 2008 and 2009 using appropriate controlled vocabulary (e.g., twin, ultrasound, cervix, prematurity) and key words (e.g., acardiac, twin, reversed arterial perfusion, twin-to-twin transfusion syndrome, amniotic fluid). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date restrictions. Studies were restricted to those with available English or French abstracts or text. Searches were updated on a regular basis and incorporated into the guideline to September 2009. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence collected was reviewed by the Diagnostic Imaging Committee of the Society of Obstetricians and Gynaecologists of Canada, with input from members of the Maternal Fetal Medicine Committee and the Genetics Committee of the SOGC. The recommendations were made according to the guidelines developed by The Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

The benefit expected from this guideline is facilitation and optimization of the use of ultrasound in twin pregnancy. SUMMARY STATEMENTS: 1. There are insufficient data to make recommendations on repeat anatomical assessments in twin pregnancies. Therefore, a complete anatomical survey at each scan may not be needed following a complete and normal assessment. (III) 2. There are insufficient data to recommend a routine preterm labour surveillance protocol in terms of frequency, timing, and optimal cervical length thresholds. (II-2) 3. Singleton growth curves currently provide the best predictors of adverse outcome in twins and may be used for evaluating growth abnormalities. (III) 4. It is suggested that growth discordance be defined using either a difference (20 mm) in absolute measurement in abdominal circumference or a difference of 20% in ultrasound-derived estimated fetal weight. (II-2) 5. Although there is insufficient evidence to recommend a specific schedule for ultrasound assessment of twin gestation, most experts recommend serial ultrasound assessment every 2 to 3 weeks, starting at 16 weeks of gestation for monochorionic pregnancies and every 3 to 4 weeks, starting from the anatomy scan (18 to 22 weeks) for dichorionic pregnancies. (II-1) 6. Umbilical artery Doppler may be useful in the surveillance of twin gestations when there are complications involving the placental circulation or fetal hemodynamic physiology. (II-2) 7. Although many methods of evaluating the level of amniotic fluid in twins (deepest vertical pocket, single pocket, amniotic fluid index) have been described, there is not enough evidence to suggest that one method is more predictive than the others of adverse pregnancy outcome. (II-3) 8. Referral to an appropriate high-risk pregnancy centre is indicated when complications unique to twins are suspected on ultrasound. (II-2) These complications include: 1. Twin-to-twin transfusion syndrome 2. Monoamniotic twins gestation 3. Conjoined twins 4. Twin reversed arterial perfusion sequence 5. Single fetal death in the second or third trimester 6. Growth discordance in monochorionic twins. Recommendations 1. All patients who are suspected to have a twin pregnancy on first trimester physical examination or who are at risk (e.g., pregnancies resulting from assisted reproductive technologies) should have first trimester ultrasound performed. (II-2A) 2. Every attempt should be made to determine and report amnionicity and chorionicity when a twin pregnancy is identified. (II-2A) 3. Although the accuracy in confirmation of gestational age at the first and second trimester is comparable, dating should be done with first trimester ultrasound. (II-2A) 4. Beyond the first trimester, it is suggested that a combination of parameters rather than a single parameter should be used to confirm gestational age. (II-2C) 5. When twin pregnancy is the result of in vitro fertilization, accurate determination of gestational age should be made from the date of embryo transfer. (II-1A) 6. There is insufficient evidence to make a recommendation of which fetus (when discordant for size) to use to date a twin pregnancy. However, to avoid missing a situation of early intrauterine growth restriction in one twin, most experts agree that the clinician may consider dating pregnancy using the larger fetus. (III-C) 7. In twin pregnancies, aneuploidy screening using nuchal transluscency measurements should be offered. (II-2B) 8. Detailed ultrasound examination to screen for fetal anomalies should be offered, preferably between 18 and 22 weeks' gestation, in all twin pregnancies. (II-2B) 9. When ultrasound is used to screen for preterm birth in a twin gestation, endovaginal ultrasound measurement of the cervical length should be performed. (II-2A) 10. Increased fetal surveillance should be considered when there is either growth restriction diagnosed in one twin or significant growth discordance. (II-2A) 11. Umbilical artery Doppler should not be routinely offered in uncomplicated twin pregnancies. (I-E) 12. For defining oligohydramnios and polyhydramnios, the ultrasonographer should use the deepest vertical pocket in either sac: oligohydramnios when < 2 cm and polyhydramnios when > 8 cm. (II-2B).

Radiofrequency ablation vs bipolar umbilical cord coagulation in the management of complicated monochorionic pregnancies

OBJECTIVE

The application of radiofrequency ablation (RFA) termination procedures to complicated cases involving monochorionic twins offers the potential of a less invasive option when compared to endoscopic techniques. The purpose of this study was to compare outcomes between these two techniques.

METHODS

A retrospective review was undertaken of all cases of complicated monochorionic twin gestations treated at the Children's Hospital of Philadelphia from July 1996 to December 2010. Cases were identified from the fetal treatment database and data extracted in a uniform fashion from the patients' charts.

RESULTS

A total of 149 cases were identified with procedures performed on 146. Indications for selective termination of one fetus were twin reversed arterial perfusion sequence in 53, severe twin-to-twin transfusion syndrome in 43, discordance for fetal anomalies in 26 and selective intrauterine growth restriction in 24. Eighty-eight cases were managed with bipolar cord coagulation (BCC) and 58 with RFA. The procedures in all cases were technically successful in achieving selective termination. The mean gestational age at the time of the procedure was 20.9 ± 2.7 weeks in the BCC group vs 20.2 ± 2.2 weeks in the RFA group (P = 0.1). The median gestational age at delivery was 34.7 (interquartile range (IQR), 29.2-38.6) weeks for the BCC group vs 33.0 (IQR, 23.4-38.9) weeks in the RFA group (P = 0.073). Mean birth weight did not differ between the two groups. The procedure-to-delivery time was 87.1 ± 42.1 days for the BCC group vs 73.8 ± 47.2 days for the RFA group (P = 0.1). Overall survival was 85.2% in the BCC group vs 70.7% in the RFA group (P = 0.014). This was attributed primarily to a survival rate of 10.5% in the RFA group compared with 31.6% in the BCC group for cases where delivery occurred before 28 weeks' gestation (P = 0.01). Premature rupture of the membranes occurred in 27.3% in the BCC group vs 13.7% in the RFA group (P = 0.05). Preterm labor was more common in the BCC group than in the RFA group (22.4 vs 7%, respectively; P = 0.009).

CONCLUSION

Despite the smaller caliber of the instrument, RFA is not associated with a decrease in the overall complication rate for selective termination procedures. The technique used for selective termination should still be determined by technical considerations but patients should be informed of the survival rate associated with each technique.

Cord occlusion followed by laser cord transection in monochorionic monoamniotic discordant twins

OBJECTIVE

To compare the outcomes of a consecutive case series of monochorionic (MC) monoamniotic (MA) discordant twins treated with umbilical cord occlusion and transection, with those of a cohort of MC diamniotic (DA) twins treated with conventional cord occlusion.

METHODS

This study included 17 MCMA twins (12 true MA and five iatrogenic) treated with cord occlusion and transection and a control group of 72 MCDA discordant twins treated during the same period with cord occlusion in a single center. Duration of surgery, rates of preterm delivery (PTD) or preterm premature rupture of membranes (PPROM) < 32 weeks and intrauterine fetal demise (IUFD), perinatal outcome and neonatal survival were prospectively recorded in both groups.

RESULTS

Median durations of surgery were 28.5 (range, 14.0-74.0) min and 24.0 (3.0-60.0) min in the cord transection and control groups, respectively (P = 0.24). There were no significant differences between cord transection and control groups in the rates of PPROM (35.3% vs. 20.8%, P = 0.22), PTD (41.2% vs. 28.2%, P = 0.29), IUFD (0% vs. 2.8%, P = 1.0) and neonatal survival (76.5% vs. 80.6%, P = 1.0). Gestational age at delivery (median 35.0 (24.5-39.0) vs. 37.1 (26.2-41.0) weeks, P = 0.21) and fetal birth weight (2215 (800-3200) g vs. 2605 (588-3830) g, P = 0.51) were similar between study groups.

CONCLUSION

Cord occlusion and transection in MCMA discordant twins resulted in similar perinatal outcomes to those of MCDA discordant twins treated with cord occlusion.

Specific complications of monochorionic twin pregnancies: twin-twin transfusion syndrome and twin reversed arterial perfusion sequence

Monochorionic twins are subjected to specific complications which originate in either imbalance or abnormality of the single placenta serving two twins. This unequal placental sharing can cause complications including twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence (TAPS), selective intrauterine growth restriction or twin reversed arterial perfusion sequence (TRAP). Monochorionicity also makes the management of these specific complications as well as that of a severe malformation in one twin hazardous since the spontaneous death of one twin exposes the co-twin to a risk of exsanguination into the dead twin and its placenta. The latter is responsible for the death of the co-twin in up to 20% of the cases and in ischemic sequelae in about the same proportions in the survivors. Although the symptoms of all these complications are very different, the keystone of their management comes down to either surgical destruction of the inter-twin anastomoses on the chorionic plate when aiming at dual survival or selective and permanent occlusion of the cord of a severely affected twin aiming at protecting the normal co-twin. This can be best achieved by fetoscopic selective laser coagulation and bipolar forceps cord coagulation respectively.

The outcome of twin reversed arterial perfusion sequence diagnosed in the first trimester

OBJECTIVE

The aim of this study was to document the mortality of twin reversed arterial perfusion (TRAP) sequence from the first trimester to planned intervention at 16-18 weeks.

STUDY DESIGN

A retrospective review was performed of the outcome of monochorionic twin pregnancies diagnosed with twin reversed arterial perfusion sequence in the first trimester.

RESULTS

Twenty-six pregnancies were diagnosed with twin reversed arterial perfusion sequence in the first trimester: 2 opted for termination of pregnancy and 24 opted for prophylactic intervention to arrest the reversed flow, which was planned at 16-18 weeks. In 8 of 24 (33%) pregnancies, spontaneous death of the pump twin occurred between diagnosis and planned intervention. In 5 of 24 (21%), there was a spontaneous arrest of flow; whereas, in 11 (46%) there was persistent flow toward the acardiac twin at 16-18 weeks.

CONCLUSION

Twin reversed arterial perfusion carries a high mortality between the first and early second trimester.

Selective reduction in complicated monochorionic pregnancies: radiofrequency ablation vs. bipolar cord coagulation

OBJECTIVE

To compare radiofrequency ablation (RFA) and bipolar cord coagulation (BPC) methods for selective fetal reduction in the treatment of complicated monochorionic (MC) multifetal gestations.

METHODS

This was a retrospective review of patients who underwent selective reduction by RFA and BPC. Computer-generated random sampling was performed to match patients who had undergone BPC with patients who had undergone RFA, in a 2 : 1 ratio, controlling for gestational age and indication. The primary outcome was fetal survival.

RESULTS

Twenty patients in the RFA group were matched with 40 patients in the BPC group. Fewer additional intra-operative procedures were performed in the RFA group compared with the BPC group: amnioinfusion, 10% vs. 75%, respectively (P < 0.01); and amnioreduction, 5% vs. 40%, respectively (P = 0.004). The overall survival rates were 87.5% in the RFA group and 88% in the BPC group (P = 0.94). Median gestational age at delivery was 36 (range, 26-41) weeks in the RFA group and 39 (range, 19-40) weeks in the BPC group (P = 0.59). Preterm delivery (at < 28, < 32 or < 37 weeks), weeks gained after the procedure and birth weight at delivery were also similar. Although the preterm premature rupture of membranes (PPROM) rate was higher in the BPC group (22.5%) compared with the RFA group (5%), the difference was not statistically significant (P = 0.09).

CONCLUSIONS

Overall fetal survival rate following selective reduction in complicated MC pregnancies is similar whether reduction is performed by RFA or BPC. Fewer additional intraoperative procedures are required for RFA than for BPC. The possibility that RFA is associated with a lower rate of postoperative PPROM than is BPC will have to be confirmed in larger series.

The use of ultrasound in fetal surgery

Obstetric ultrasound (US) is an integral part of fetal surgery for open and minimally invasive techniques. With advances in US imaging, the ability to refine diagnosis, predict prognosis, and contribute to fetal treatment continues to grow. Current research in fetal diagnosis and treatment includes identifying the most reliable sonographic features for determining prognosis before and after surgery.

Umbilical cord occlusion for selective feticide in complicated monochorionic twins: a systematic review of literature

The aim of this study was to review literature concerning selective feticide (SF) in monochorionic pregnancies complicated with twin-twin transfusion syndrome, twin reversed arterial perfusion, severe malformation, and discordant growth. The remaining twins' outcomes were stratified for indication and surgical technique. Three hundred forty-five cases of SF were reviewed. Premature rupture of membranes was described in all the procedures and complicated 76/345 (22%) pregnancies within 4 postoperative weeks (59%) or later (41%; P = .52). Fetal demise accounted for 51/345 (15%), more frequently within 2 postoperative weeks (79%) than thereafter (21%; P = .004; odds ratio [OR], 6.12; 95% confidence interval [CI], 1.81-20.70). Improved survival rate was achieved in surgeries after 18 weeks (89%) than earlier (69%; P = .02; OR, 0.28; 95% CI, 0.10-0.80) without differences for indication. Survivors were 86% after radiofrequency ablation, 82% after bipolar cord coagulation, 72% after laser cord coagulation, 70% after cord ligation. In spite of favorable outcomes, the optimal surgical approach remains undetermined.