First-trimester intervention in twin reversed arterial perfusion sequence: does size matter?

A systematic review of early intrauterine intervention at 12 + 0 to 16 + 6 weeks in twin reversed arterial perfusion sequence

There is some evidence that in twin reversed arterial perfusion sequence, intervention at early gestational age could prevent a spontaneous death of the pump twin, achieving a better global survival.

OBJECTIVE

To review the perinatal outcomes of early intervention in pregnancies complicated by twin reversed arterial perfusion (TRAP) sequence.

STUDY DESIGN

A comprehensive search from inception to December 2022 was conducted on databases including MEDLINE, EMBASE, Cochrane Library and LILACS. All studies that reported intervention in twin or triplet pregnancy complicated with TRAP sequence at 12 + 0 to 16 + 6 weeks of gestation were eligible. A descriptive and bivariate analysis was performed.

RESULTS

Out of the 222 full-text articles, 44 studies reporting 108 cases of early intervention in TRAP sequence were included. A successful procedure was achieved in 105 (95.5 %) interventions: 89 (94.7 %) among twin pregnancies and 16(100 %) among triplet pregnancies. An overall livebirth rate was achieved in 75 patients (70.8 %): intrafetal laser group 55 (73.3 %), radiofrequency 10 (76.9 %) and endoscopic laser 3 (75.0 %). The median gestational age at delivery was 38 + 0 (37 + 4 - 39 + 4) weeks. The median treatment-delivery interval was 23 + 2 (IQR, 21 + 0-25 + 6) weeks. The most frequent adverse outcomes reported were preterm labor in 7 (13.7 %) patients. There were no severe adverse maternal outcomes.

CONCLUSION

Early intervention with intrafetal laser and radiofrequency in TRAP sequence achieves a livebirth rate of the pump twin of about 75 %.

"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.

The Management of Acardiac Twinning: Twin Reverse Arterial Perfusion Sequence - An International Survey

INTRODUCTION

The optimal approach and therapy method for the acardiac twin with a reverse arterial perfusion sequence has not yet been established. The aim of this study was to determine the clinical practice patterns among international fetal therapy units in their management of these cases.

METHODS

A survey was sent to fetal centers across the world via email between December 2020 and December 2021.

RESULTS

Responses were obtained from 77% contacted centers. The most frequent ultrasound variables used in the evaluation of twin reverse arterial perfusion sequence include echocardiographic assessment of the pump twin and umbilical artery Doppler waveforms in the acardiac and pump twins, in 90% and 80% of the centers, respectively. Most centers in Europe and Latin America propose an in utero intervention in all cases. Most centers in Europe and Latin America prefer interstitial laser ablation, whereas radiofrequency ablation (RFA) is preferred in North America. The earliest gestational age for an intervention is on mean 13 weeks in Europe, which is earlier than the other geographic areas (p = 0.001).

CONCLUSIONS

Most centers agreed that antenatal evaluation should include echocardiography along with the UA Doppler waveform measurements, and the most frequently used interventions were interstitial laser ablation or RFA at a median between 14 and 26 weeks.

Directive clinique no 440 : Prise en charge de la grossesse gémellaire monochoriale

OBJECTIF

Cette directive clinique passe en revue les données probantes sur la prise en charge de la grossesse gémellaire monochoriale normale et compliquée.

POPULATION CIBLE

Les femmes menant une grossesse gémellaire ou multiple de haut rang. BéNéFICES, RISQUES ET COûTS: L'application des recommandations de cette directive devrait améliorer la prise en charge des grossesses gémellaires (ou multiples de haut rang) monochoriales compliquées et non compliquées. Ces recommandations aideront les fournisseurs de soins à surveiller adéquatement les grossesses gémellaires monochoriales ainsi qu'à détecter et prendre en charge rapidement les complications associées de façon optimale afin de réduire les risques de morbidité et mortalité périnatales. Ces recommandations impliquent une surveillance échographique plus fréquente en cas de grossesse monochoriale qu'en cas de grossesse bichoriale. DONNéES PROBANTES: La littérature publiée a été colligée par des recherches dans les bases de données PubMed et Cochrane Library au moyen de termes MeSH pertinents (Twins, Monozygotic; Ultrasonography, Prenatal; Placenta; Fetofetal Transfusion; Fetal Death; Fetal Growth Retardation). Les résultats ont été restreints aux revues systématiques, aux essais cliniques randomisés et aux études observationnelles. Aucune date limite n'a été appliquée, mais les résultats ont été limités aux contenus en anglais ou en français. MéTHODES DE VALIDATION: Les auteurs principaux ont rédigé le contenu et les recommandations et ils se sont entendus sur ces derniers. Le conseil d'administration de la SOGC a approuvé la version définitive aux fins de publication. Les auteurs ont évalué la qualité des données probantes et la force des recommandations en utilisant le cadre méthodologique GRADE (Grading of Recommendations Assessment, Development and Evaluation). Voir l'annexe A en ligne (tableau A1 pour les définitions et tableau A2 pour l'interprétation des recommandations fortes et conditionnelles [faibles]). PROFESSIONNELS CONCERNéS: Spécialistes en médecine fœto-maternelle, obstétriciens, radiologues, échographistes, médecins de famille, infirmières, sages-femmes, résidents et autres fournisseurs de soins de santé qui s'occupent de femmes menant une grossesse gémellaire ou multiple de haut rang. RéSUMé POUR TWITTER: Directive canadienne (SOGC) pour le diagnostic, la surveillance échographique et la prise en charge des complications de la grossesse gémellaire monochoriale (p. ex., STT, TAPS, retard de croissance sélectif, cojumeau acardiaque, monoamnionicité et mort d'un jumeau). DÉCLARATIONS SOMMAIRES: RECOMMANDATIONS.

Guideline No. 440: Management of Monochorionic Twin Pregnancies

OBJECTIVE

This guideline reviews the evidence-based management of normal and complicated monochorionic twin pregnancies.

TARGET POPULATION

Women with monochorionic twin or higher order multiple pregnancies.

BENEFITS, HARMS, AND COSTS

Implementation of these recommendations should improve the management of both complicated and uncomplicated monochorionic (and higher order multiple) twin pregnancies. They will help users monitor monochorionic twin pregnancies appropriately and identify and manage monochorionic twin complications optimally in a timely manner, thereby reducing perinatal morbidity and mortality. These recommendations entail more frequent ultrasound monitoring of monochorionic twins compared to dichorionic twins.

EVIDENCE

Published literature was retrieved through searches of PubMed and the Cochrane Library using appropriate MeSH headings (Twins, Monozygotic; Ultrasonography, Prenatal; Placenta; Fetofetal Transfusion; Fetal Death; Fetal Growth Retardation). Results were restricted to systematic reviews, randomized controlled clinical trials, and observational studies. There were no date limits, but results were limited to English or French language materials.

VALIDATION METHODS

The content and recommendations were drafted and agreed upon by the principal authors. The Board of the SOGC approved the final draft for publication. The authors rated the quality of evidence and strength of recommendations using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. See online Appendix A (Tables A1 for definitions and A2 for interpretations of strong and conditional [weak] recommendations).

INTENDED AUDIENCE

Maternal-fetal medicine specialists, obstetricians, radiologists, sonographers, family physicians, nurses, midwives, residents, and other health care providers who care for women with monochorionic twin or higher order multiple pregnancies.

TWEETABLE ABSTRACT

Canadian (SOGC) guidelines for the diagnosis, ultrasound surveillance and management of monochorionic twin pregnancy complications, including TTTS, TAPS, sFGR (sIUGR), acardiac (TRAP), monoamniotic twins and intrauterine death of one MC twin.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Timing of intra-fetal laser therapy for twin reversed arterial perfusion (TRAP) sequence: Retrospective series and systematic review and meta-analysis

OBJECTIVE

To estimate the neonatal survival rate after intra-fetal laser (IFL) treatment for twin reversed arterial perfusion (TRAP) sequence, and to investigate the effect of gestational age at the time of procedure.

METHODS

Retrospective cohort study of TRAP sequences followed at our institution from 2013-2020. Systematic review and meta-analysis of the neonatal survival rate after IFL was conducted. Both diamniotic and monoamniotic monochorionic pregnancies were included. A subgroup analysis to compare outcomes according to gestational age at procedure (<16⁺⁰ weeks or ≥16⁺⁰ weeks) was planned.

RESULTS

Thirteen pregnancies were followed at our center and seven were treated with IFL: the survival rate was 57%. Ten studies published between 2008 and 2020 for a total of 156 cases were included in the meta-analysis. The overall neonatal survival after IFL was 79% (95% CI 0.72-0.86, I² 22%). A random-effects model comparing neonatal survival for IFL performed <16⁺⁰ weeks versus ≥16⁺⁰ weeks showed no significant difference between the two groups (OR = 0.93; 95% CI 0.37-2.33).

CONCLUSION

IFL is a safe and minimally invasive technique for the treatment of TRAP sequence, with a survival rate of 79%. Gestational age at treatment (before or after 16 weeks) does not seem to affect neonatal survival rate.

Outcome of TRAP Sequence Treated in the First Trimester - A Ten-Year Single-Center Experience

PURPOSE

 To evaluate the outcome of first trimester intervention by intrafetal laser (IFL) in pregnancies complicated by twin reversed arterial perfusion (TRAP).

MATERIALS AND METHODS

 For a 10-year study period, all patients with TRAP diagnosed < 14.0 weeks of gestation were retrospectively analyzed for intrauterine course and outcome. Monoamniotic pregnancies were excluded. Patients were offered either intervention by IFL in the first trimester, expectant management, or termination of pregnancy (TOP). Adverse outcome was defined as either intrauterine death (IUD), neonatal death, or preterm birth.

RESULTS

 In 45 cases TRAP was diagnosed. 17 monoamniotics were excluded. The cohort was divided into two groups according to management. Group A: 24 cases underwent IFL and group B: 4 cases were managed expectantly. No patient opted for TOP. In group A, 70.8 % of pump twins were born alive, including one preterm delivery, and 29.2 % died within four days after the intervention. All 4 expectantly managed cases in group B had an adverse outcome (1 preterm delivery, 3 IUDs < 15.0 weeks). There were no neonatal deaths. In cases treated by IFL, a comparison of survivors and non-survivors identified no significant differences in gestational age at IFL or any of the assessed biometrical and functional parameters. There was a trend towards better outcome in the second half of the study period.

CONCLUSION

 IFL in first trimester TRAP sequence is technically feasible but is associated with significant mortality, albeit less than previously reported. No risk stratification is possible using the investigated parameters. However, there seems to be a learning curve.

Ultrasound assessment of twin reversed arterial perfusion sequence for the prediction of adverse pregnancy outcomes in the first trimester

OBJECTIVE

To investigate twin reversed arterial perfusion (TRAP) sequence for the prediction of TRAP-related adverse pregnancy outcomes at the gestational age of 11-14 weeks.

METHODS

Pregnant women in the first trimester diagnosed with TRAP were recruited at West China Second University Hospital from January 2015 to June 2018. Systematic screening for the pump twin's crown-rump length (CRL) and acardiac twin's upper pole-rump length (URL) was conducted using ultrasonic detection. The (CRL - URL)/CRL and URL/CRL ratios were used to assess the pregnancy outcomes for the pump twin. Twenty-one pregnant women aged 21-39 years with a gestation of 11-14 weeks were recruited.

RESULTS

TRAP was diagnosed on average (± standard deviation (SD)) at pregnancy week 13.1 ± 0.18. The pump twins' mean (± SD) CRL was 6.65 ± 1.1 cm. The incidence of intrauterine death for the pump twins was 19.0% (n = 4), the miscarriage rate was 14.3% (n = 3), and the live birth rate was 66.7% (n = 14). The (CRL - URL)/CRL ratios between the nonsurvival (intrauterine death and miscarriage) and survival groups significantly differed (0.33 ± 0.08 vs. 0.58 ± 0.08, p < 0.05). Similarly, the URL/CRL ratios between the nonsurvival and survival groups significantly differed (0.67 ± 0.08 vs. 0.42 ± 0.08, p < 0.05).

CONCLUSION

The (CRL - URL)/CRL and URL/CRL ratios were valuable indicators for determining pregnancy outcomes of pump twins with TRAP at an early gestational age.

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.

Alterations in Fetal Doppler Parameters Before and Twenty-Four Hours After Radiofrequency Ablation for Twin Reversed Arterial Perfusion Sequence

Objective

To evaluate alterations in the fetal Doppler parameters of pump fetuses before and 24 h after radiofrequency ablation surgery for twin reversed arterial perfusion sequence (TRAPs).

Methods

This is a retrospective study of 28 pump fetuses in TRAPs and 28 normal control twins between 2016 and 2021. The fetal Doppler parameters, including the umbilical artery pulsatility index (UA-PI), middle cerebral artery peak systolic velocity (MCA-PSV), middle cerebral artery pulsatility index (MCA-PI), and cerebroplacental ratio (CPR), of the controls, and pump fetuses before and 24 h after surgery were compared.

Results

An increasing trend and a further increase in the MCA-PSV, MCA-PI, MCA-PSV Z score, and MCA-PI Z score after surgery were observed in pump fetuses with gestational age (GA) ≥20 weeks; however, such changes were not observed in those with a GA of <20 weeks. The UA-PI and CPR before and after surgery were not different between control and pump fetuses, whether the GA was ≥20 or <20 weeks.

Conclusion

In the middle second trimester, the pump fetus might suffer from high cardiac output rather than hypoxemia before surgery and congestive heart failure, or hemodilutional anemia after surgery. This may provide some theoretical evidence in favor of early intervention, rather than waiting for a more advanced GA, to avoid unnecessary hemodynamic alterations.

Outcome of radiofrequency ablation for selective fetal reduction before vs at or after 16 gestational weeks in complicated monochorionic pregnancy

OBJECTIVE

To investigate whether gestational age at intervention (< or ≥ 16 weeks) and other factors affect the risk of loss of the cotwin after selective fetal reduction using radiofrequency ablation (RFA) in monochorionic (MC) pregnancy.

METHODS

This was a single-center retrospective analysis of 63 consecutive RFA procedures performed at our institution from January 2011 to October 2019 for selective fetal reduction in complicated MC pregnancies. Indications for RFA were twin reversed arterial perfusion sequence (13 cases), twin-to-twin transfusion syndrome (12 cases), twin anemia-polycythemia sequence (two cases), selective fetal growth restriction (10 cases), discordant anomalies (17 cases) and multifetal pregnancy reduction in triplets or quadruplets with a MC pair (nine cases). Twenty-six (41.3%) of these procedures were performed before and 37 (58.7%) after 16 weeks. Potential factors that could affect the risk of loss of the cotwin, including gestational age at RFA, order of multiple pregnancy, amnionicity, indication for RFA and number of ablation cycles, were assessed first by univariate analysis and then by multivariate analysis.

RESULTS

There were 17 (27.0%) cotwin losses. Ablation cycles numbering four or more was the only factor among those investigated to be associated with loss of the cotwin after RFA (P = 0.035; odds ratio, 5.21), while the indication for RFA, order of multiple pregnancy, amnionicity and gestational age at RFA had no effect. Comparing RFA performed at < 16 vs ≥ 16 weeks, there was no difference in the rate of cotwin loss (23.1% vs 29.7%; P = 0.558) or preterm prelabor rupture of the membranes before 34 weeks (7.7% vs 5.4%; P = 0.853), or in the median gestational age at delivery (36.2 vs 37.3 weeks; P = 0.706).

CONCLUSIONS

RFA is a promising tool for early selective fetal reduction in MC pregnancy before 16 weeks. Four or more ablation cycles is a major risk factor for cotwin loss. Careful assessment pre- and post-RFA, together with proficient operative skills to minimize the number of ablation cycles, are the mainstay to ensure that this procedure is effective and safe. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Bibliometric analysis of research hotspots and development trends in selective fetal reduction

AIM

To evaluate the theme trends and knowledge structure of multifetal pregnancy reduction (MPR)-related literature by using bibliometric analysis.

METHODS

Published scientific papers regarding MPR were retrieved from the PubMed database. Data extraction and statistics were conducted using Bibliographic Item Co-Occurrence Matrix Builder (BICOMB). Furthermore, gCLUTO software was used in the study for bi-clustering analysis and strategic diagram analysis.

RESULTS

According to the search strategy, 906 total papers were included. Among all the extracted MeSH terms, 41 high frequency ones were identified and hotspots were clustered into four categories. In the strategic diagram, research on intrauterine treatment of MPR was most well developed. In contrast, statistical data on the sequelae of fetal reduction surgery and applications of MPR in assisted reproductive technologies were relatively immature.

CONCLUSION

The analysis of common terms among the high-frequency network terms in multiparous pregnancy reduction can help researchers and clinicians understand the hotspots, key topics, and issues to be discovered on MPR. Research on intrauterine treatment of MPR was most well developed.

‘TRAP-ped with an Acardius’: Case Series of Twin Reversed Arterial Perfusion (TRAP) Sequence and Review of Literature

Twin reversed arterial perfusion (TRAP) sequence is a rare but severe condition that affects monochorionic (MC) multifetal pregnancies. In twin pregnancies, it is characterized by a normally developed twin and another twin with missing heart function (acardiac twin or TRAP twin). A variety of risks and complications may affect the normal twin. Management of such pregnancies can be either expectant or interventional. We report four cases of TRAP sequence treated in our institutions and supply an overview on currently existing literature. This case series demonstrates the heterogeneity in manifestations and clinical course of patients affected by this condition. Furthermore, it includes an acardius amorphous of considerable size delivered at 35.6 weeks of gestation.

US Evaluation of Twin Pregnancies: Importance of Chorionicity and Amnionicity

The twin birth rate is increasing in the United States. Twin pregnancies can be dichorionic or monochorionic (MC). MC twins account for 20% of twin pregnancies but 30% of all-cause pregnancy-related complications. This article describes the imaging findings that establish chorionicity and amnionicity. Ideally, these are established in the first trimester when accuracy is high, but they can also be determined later in pregnancy. Complications unique to MC twin pregnancy include twin-twin transfusion syndrome, twin anemia polycythemia sequence, twin reversed arterial perfusion sequence, and selective fetal growth restriction. The US features, staging systems, and management of these complications are reviewed, and the consequences of MC twin demise are illustrated. Ongoing surveillance for these conditions starts at 16 weeks gestation. Monoamniotic (MA) twins are a small subset of MC twins. In addition to all of the MC complications, specific MA complications include cord entanglement and conjoined twinning. Radiologists must be able to determine chorionicity and amnionicity and should be aware of potential complications so that patients may be referred to appropriate regional specialized centers. A proposed algorithm for referral to specialized fetal treatment centers is outlined. Online supplemental material is available for this article. ^©RSNA, 2019.

Twin Reversed Arterial Perfusion Sequence: Current Treatment Options

Twin reversed arterial perfusion (TRAP) sequence is a specific and severe complication of monochorionic multiple pregnancy, characterized by vascular anastomosis and partial or complete lack of cardiac development in one twin. Despite its rarity, interest in the international literature is rising, and we aimed to review its pathogenesis, prenatal diagnostic features and treatment options. Due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin, the management of these pregnancies aims to maximize the pump twin's chances of survival. If treatment is needed, the best timing of intervention is still debated, although the latest studies encourage intervention in the first trimester of pregnancy. As for the technique of choice to interrupt the vascular supply to the acardiac twin, ultrasound-guided laser coagulation and radiofrequency ablation of the intrafetal vessels are usually the preferred approaches.

Morphology, intrafetal vascular pattern, and umbilical artery Doppler indices of acardiac twins

BACKGROUND

Twin reversed arterial perfusion (TRAP) sequence consists of acardiac twin (A) paradoxically perfused by pump twin (P) through an umbilical artery (UA). We proposed characterization of acardiac twins with intrafetal vascular pattern (IVP), and assessed its correlation with morphology and UA Doppler indices.

METHODS

We prospectively evaluated 21 cases of TRAP sequence. Morphology (acardia vs hemicardia) and IVP (simple vs complex) of acardiac twins were characterized with ultrasound and color Doppler. Twins weight ratio (A/P Wt) and UA Doppler indices of acardiac and pump twins including (1) difference of systolic/diastolic ratio (UA ∆S/D), (2) difference of resistance index (UA ∆RI), and (3) ratio of pulsatility index (UA PI A/P) were calculated.

RESULTS

The median (min, max) gestational age at diagnosis was 18 (11, 27) weeks. Acardia (n = 14) were associated with simple IVP (n = 16) (P < .05). After exclusion of acardia with complex IVP (n = 1), the A/P Wt, UA ∆S/D, UA ∆RI, and UA PI A/P of acardia with simple IVP (n = 13), hemicardia with simple IVP (n = 3), and hemicardia with complex IVP (n = 4) were not significantly different (P > .05).

CONCLUSIONS

Most of acardiac twins were acardia with simple IVP. Morphology and IVP of acardiac twins were not associated with UA Doppler indices.

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.

TRAP Sequence in Monochorionic/Monoamniotic (MC/MA) Discordant Twins: Two Cases Treated with Fetoscopic Laser Surgery

INTRODUCTION

Ablation of the acardiac twin umbilical cord in the TRAP protects the normal donor twin.

MATERIALS AND METHODS

Two case descriptions, one of interstitial laser photocoagulation and one of laser umbilical cord occlusion (L-UCO) of the acardiac twin in monochorionic monoamniotic pregnancies are reported.

RESULTS

L-UCO in two pregnancies with TRAP syndrome in the second trimester resulted in intrauterine fetal death in both cases after 1 month. Case 1 had no detectable cause of fetal death. Case 2 had rupture of the amniotic sac causing anhydramnios and acute chorioamnionitis. A groove on the umbilical cord of the normal twin indicated a cord stricture due to cord entanglement.

CONCLUSION

Our experience confirms that the best timing and optimal treatment of MC/MA twins complicated by TRAP sequence still remains a controversial clinical issue. Cord entanglement may continue be a potential clinical risk factor for adverse perinatal outcome even after ablation therapy.