Novel autopsy and genetic findings in an acardiac twin: case report and literature review.

Twin Reversed Arterial Perfusion Sequence.

Introduction. Twin reversed arterial perfusion (TRAP) sequence is a rare complication of multiple pregnancy caused by defects in early embryogenesis. The pump twin supplies the acardiac recipient twin with blood, and although the pump twin is usually structurally normal, congenital anomalies have sometimes been reported. We report a case of twin reversed arterial perfusion sequence with feet polydactly in the surviving pump twin. This was the 1st case reported in Fallujah city, Iraq. Case report. A 22 years old. gravida 2, para 0. abortion 1, full term lady presented to the delivery room with labour pain with no history of any prenatal care. She gave no history of any familial congenital anomaly and there was no history of consanguinity with her hasbund. She has been referred for cesearian section delivery as an emergency as there was no progress in labour. Ultrasound examination at the delivery room revealed the diagnosis of monozygotic twin, one was normal & the 2nd was diagnosed as (abnormal) with difficulty in visualization of the fetal parts and gender. Conclusion. Twin-Reversed Arterial Perfusion (TRAP) sequence is a rare complication of monozygotic multiple gestation. Accurate antenatal diagnosis is essential to improve the prognosis of this rare entity.

Background: Twin reversed arterial perfusion (TRAP) sequence is the most severe form of twin to twin transfusion syndrome. Survival of the pump twin is threatened by extreme prematurity from polyhydramnios and cardiac failure, necessitating interventions. Rarely, interventions are indicated as a result of maternal life-threatening complications. The management of an acardiac-myelacephalus variant of TRAP sequence, complicated by severe maternal respiratory distress from tense polyhydramnios is presented in this report. Case presentation: A 29-year-old G3P2, Alive2 was referred to the Perinatal Unit on account of ultrasound diagnosed twin gestation with demise of one twin at an estimated gestational age (EGA) of 29 weeks. She was in severe respiratory distress with central cyanosis, and grossly distended abdomen. Ultrasonography revealed twin gestation with cardiac activity in only one twin and polyhydramnios. The second twin had no recognizable human body structure and retrograde umbilical arterial flow. TRAP sequence with tense polyhydramnios was diagnosed. The respiratory distress was relieved with serial reductive amniocentesis, and she was managed conservatively until an EGA of 34 weeks, when she delivered a live twin that weighed 2.05 kg, and an amorphous twin with a rudimentary limb that weighed 1.82 kg following spontaneous rupture of membranes. Monochorionic placentation was confirmed at delivery. The pump twin was discharged in a satisfactory state after a period of observation. Conclusion: TRAP sequence may be easily misdiagnosed due to its rarity, with adverse consequences. Accurate diagnosis of the condition, and the provision of basic facilities for in utero interventions when indicated are necessary for fetal salvage.

Prognostic value of nuchal translucency and ductus venosus Doppler in TRAP sequence.

The twin reversed arterial perfusion (TRAP) sequence, also known as fetus acardius, occurs in 0.3 % of monozygotic twin gestations, which amounts to a frequency of about 1 per 35,000 deliveries [1, 2]. There have been only two reports on antenatal three-dimensional (3D) sonographic diagnosis of the TRAP sequence during pregnancy [3, 4]. The HDlive is a new surface render mode involving the use of skin-like colors, and ‘‘its system uses an adjustable light source, giving the operator the opportunity to create lighting and shadowing effects and thereby increasing depth perception’’ [5]. There have been four reports on fetal, placental, and umbilical cord ultrasound images using the 3D HDlive rendering mode [5–8]. Employing 3D HDlive with new skin-like colors, we can achieve a natural and anatomically realistic appearance of the embryo and fetus in utero. However, there has been no reports on 3D HDlive rendering displays of the TRAP sequence in the first trimester of pregnancy. There have been five reports on reverse end-diastolic velocity in umbilical artery velocimetry with an adverse pregnancy outcome at less than 14 weeks of gestation, which suggested that reverse end-diastolic umbilical artery velocity waveforms might be an ominous sign in early pregnancy [9–13]. However, there are no sonographic findings in the first trimester that can help to distinguish between pregnancies resulting in death of the pump twin from those that will survive until prophylactic intervention at 16–18 weeks in TRAP sequence cases [14]. In this report, we present our experience of a TRAP sequence reconstructed employing the 3D HDlive rendering mode, and discuss the reverse end-diastolic blood flow velocity waveform in the umbilical artery of a pump twin with an adverse pregnancy outcome in the first trimester. A 33-year-old pregnant Japanese woman, gravida 1, para 0, was referred to our ultrasound clinic because of a suspected TRAP sequence at 11 weeks and 6 days of gestation. The 2D sonography and the 3D surface rendering mode (Voluson E8, GE Healthcare, Milwaukee, WI, USA) showed a normal pump twin and small acardiac twin with acrania and absence of the heart and upper limbs (Fig. 1). The crown-rump length of the pump twin was 43.3 mm (consistent with the corresponding age), and no gross fetal anomaly was noted. The longitudinal distance between the upper pole and rump of the acardiac fetus was 27.6 mm. The 3D HDlive rendering mode provided anatomically realistic images for TRAP sequence diagnosis (Fig. 2). Color and pulsed Doppler sonography revealed a reverse end-diastolic umbilical artery velocity in the pump twin at 13 weeks and 1 day of gestation (Fig. 3a). There was a single-artery umbilical cord between the placenta and acardiac fetus, and a reversed tiny absent diastolic umbilical artery velocity was noted (Fig. 3b). Fetal demise of the pump twin was confirmed at 14 weeks’ gestation. Delivery C. Tenkumo H. Tanaka M. Ito E. Uketa N. Mori U. Hanaoka K. Kanenishi T. Hata (&) Department of Perinatology and Gynecology, Kagawa University School of Medicine, 1750-1 Ikenobe, Miki, Kagawa 761-0793, Japan e-mail: toshi28@med.kagawa-u.ac.jp

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). 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). 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. 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.

Triplet pregnancy complicated by two acardiac fetuses

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

Twin reversed arterial perfusion (TRAP) sequence is a high-risk condition in monochorionic twin pregnancies, in which adverse outcomes of the pump twin are closely related to the duration and magnitude of abnormal perfusion. Early treatment with minimally invasive fetal techniques may reduce procedure-related morbidity and improve pregnancy outcomes. In this case report, we describe the first successful application of early fetal radiofrequency ablation at 16 weeks of gestation for the treatment of TRAP sequence in Vietnam. This report emphasizes the rationale for early intervention, the minimally invasive nature of the procedure, and the favorable clinical outcome, contributing practical insights to contemporary fetal therapy practice. We report a case of monochorionic twin pregnancy complicated by twin reversed arterial perfusion (TRAP) sequence, diagnosed and treated at 16 weeks of gestation. Ultrasound and Doppler examination demonstrated persistent reversed arterial perfusion to the acardiac twin without evidence of progressive cardiac failure in the pump twin. Given the early gestational age and the short distance between the umbilical cord insertion of the acardiac twin and the pump twin (approximately 1 cm), intrafetal radiofrequency ablation was performed under continuous ultrasound guidance to occlude the blood supply to the acardiac twin. The procedure was successfully completed with a single percutaneous entry, resulting in immediate cessation of reversed perfusion. No procedure-related complications, including membrane rupture or preterm birth, were observed during follow-up. The patient was managed on an outpatient basis thereafter, and the pregnancy was completed at 37 weeks of gestation with the delivery of a male neonate weighing 2600gram, with Apgar scores of 9 and 10 at 1 and 5 minutes, respectively. Early fetal radiofrequency ablation at 16 weeks of gestation is a feasible and minimally invasive treatment option for TRAP sequence. This first reported Vietnamese case highlights the potential benefits of early intervention in reducing invasiveness and procedure-related risks while achieving favorable perinatal outcomes.

Twin reversed arterial perfusion (TRAP) sequence: A case of an acardiac parabiotic twin.

The twin reversed arterial perfusion (TRAP) sequence is a rare complication associated with monochorionic twins. It is characterized by blood flow from the umbilical artery of the normal (pump) twin to the umbilical artery of the abnormal (acardiac) twin via artery-to-artery anastomosis. This condition is associated with 100% mortality in the acardiac twin and a high rate of perinatal morbidity and mortality in the pump twin, primarily due to intrauterine hypoxic injury, heart failure, and prematurity. Following delivery, the surviving pump twin may experience adverse neurodevelopmental outcomes and heart failure, necessitating ongoing follow-up care. The goal of managing pregnancies complicated by the TRAP sequence is to deliver a healthy, near-term pump twin through early detection, timely intervention, and continuous follow-up. However, in low-resource settings, such as the case presented here, the condition may progress undiagnosed into the third trimester due to a lack of experienced physicians and/or obstetric ultrasound scans. This case report serves as an entry point for a comprehensive review of the literature on management options for the TRAP sequence, specifically focusing on factors to consider when managing patients conservatively in resource-limited environments or in cases that are referred or diagnosed late.

A Taiwan's experience: A case report and review of literature of successful early intrauterine treatment with radiofrequency ablation in twin reversed arterial perfusion (TRAP) sequence

Twin-reversed arterial perfusion (TRAP) sequence is a rare and compromised complication in monochorionic pregnancies. The retrograde blood flow through placental communicating vessels is mainly involved to develop the syndrome. Increased cardiac output in the pump twin can lead to severe clinical manifestations. Various surgical techniques to occlude vascular communications between the pump twin and acardiac twin have been reported. A woman with TRAP sequence, at 22 weeks of gestation, complicated with progressive polyhydramnios underwent fetoscopic laser photocoagualtion of vascular communications on the placental surface. Fetoscopic observation demonstrated one artery-to-artery anastomosis and one venous-to-venous anastomosis from the pump twin to the acardiac twin, and these communications were successfully photocoagulated. The patient delivered a 2308-g female infant at 34 weeks and 1 day of gestation, following premature rupture of membrane. The infant is now 1 year old without any neurological problem. Fetoscopic laser photocoagulation of placental communicating vessels can be the procedure of choice for TRAP sequence.

Monochorionic triplet pregnancy is a rare condition, and twin-reversed arterial perfusion (TRAP) sequence and severe selective fetal growth restriction (FGR) are associated with high perinatal morbidity and mortality rates. We report a case of TRAP sequence and selective FGR typeIIconcurrently complicating a monochorionic triplet pregnancy. Fetoscopic laser surgery (FLS) was performed at 16 + 1 weeks of gestation and was technically successful. Inter-fetus placental anastomoses were coagulated. The pregnancy continued until 28 + 4 weeks of gestation, when the patient presented with preterm rupture of membranes and preterm labor. Two live female newborns were delivered by a cesarean section, and their postnatal course of the neonates was uneventful and in accordance with their gestational age at birth. To our knowledge, this is the first case report of FLS resulting in favorable outcomes for a monochorionic triplet pregnancy concurrently complicated with TRAP sequence and selective FGR type II.

Twin Reversed Arterial Perfusion (TRAP) sequence is a rare complication of monochorionic twin pregnancies characterized by reversed blood flow from the pump twin to a nonviable acardiac twin. This study aims to share the clinical outcomes and procedural details of TRAP sequence cases managed at our tertiary fetal therapy center, with emphasis on various intrauterine treatment modalities. We conducted a retrospective review of 20 pregnancies diagnosed with TRAP sequence and managed at a tertiary fetal therapy unit between January 2018 and July 2025. Diagnosis was confirmed via prenatal ultrasonography and Doppler imaging. Patients underwent intrauterine intervention-radiofrequency ablation (RFA), microwave ablation (MWA), intrafetal laser (IFL), or bipolar cord coagulation-based on gestational age, acardiac twin size, and hemodynamic status of the pump twin. Twenty pregnancies diagnosed with TRAP sequence were included. The median maternal age was 32 years (range: 22-47). Both diagnosis and intervention occurred at a median gestational age of 20 weeks (range: 12-29). Invasive treatment was performed in 19 cases: RFA (n = 10), IFL (n = 4), cord coagulation (n = 3), and MWA (n = 2). The median time from procedure to delivery was 98 days (range: 1-135). Overall live birth rate was 80% (16/20), and neonatal survival rate was 75% (15/20). Fetal interventions can significantly enhance survival in TRAP pregnancies, including those referred at advanced gestational ages. Early identification of risk indicators and tailored procedural planning are critical for improving outcomes. Our findings underscore the efficacy of minimally invasive therapies in optimizing prognosis for the pump twin.