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 Hemodynamic Responses to Arterial Occlusion of Acardiac Twins.

The objective of this study was to comprehensively assess fetal hemodynamic adaptions to occlusive procedures. Twin pregnancies complicated with acardiac twin and hydrops fetalis of the pump twin were recruited. The occlusive procedures - either alcoholization, radiofrequency ablation, coil embolization or occlusive glue - were performed under ultrasound guidance. Various hemodynamic parameters were assessed before, shortly after, then every 6 h for 48 h and 2-4 weeks after the procedures. Seven pregnancies were recruited. The median (range) gestational age of intervention was 21 (17-26) weeks of gestation. Before the procedures, all cases showed normal cardiac function. Just after the procedures, all cases showed an increase in Tei index and isovolumic relaxation time but returned to preocclusion levels within 6-48 h, except for two cases that were persistently high. Increased preload and poor shortening fraction were observed in two cases, leading to heart failure, with one recovery and one death in utero. Five out of the seven cases got through the critical period with a gradual return to normal hemodynamics, ending with the disappearance of hydrops and successful outcomes. It was concluded that the occlusive procedure could aggravate the overworked heart, leading to heart failure. Preocclusion preload index and Tei index may predict risk of heart failure due to the occlusion. This small series strongly suggests that the occlusion should be performed before the deterioration of cardiac function.

Spontaneous triplet pregnancy and trap sequence, case report.

BACKGROUND: Spontaneous multiple pregnancies are rare, and the incidence of spontaneous triplet pregnancy is about 1/4000. TRAP (Twin Reversed Arterial Perfusion) sequence has acardiac foetus with non-viable multiple anomalies, and there is a pump foetus which feeds this foetus with placental anastomoses. TRAP sequence phenomena is quite rare in triplet pregnancies. CASE PRESENTATION: The patient who applied to our clinic was 30 years old. Monochorionic diamniotic triplet pregnancy was detected by ultrasonographic examination. First amniotic sac had one foetus (Foetus A). Ultrasonographic evaluation of Foetus A revealed gestational age of 31 weeks, adequate amniotic fluid and no fetal structural anomalies. The second amniotic sac contained 2 foetuses and polyhydromnios. Ultrasonic measurements of Foetus B were consistent with 32 weeks gestational age. Color flow doppler indicated Foetus B was the pump foetus. Foetus C was an acardiac foetus with no sonographic visualization of cranium, thoracic organs or extremities, but abdominal circumference consistent with 28 weeks. Pregnancy was followed conservatively and evaluated regularly by ultrasonography twice a week. When prolonged bradycardia was detected in fetus B at 35 4/7 weeks, emergency cesarean section was performed. Two healthy fetuses weighing 2 kg were delivered each with an 8/10 APGAR score (Appearance, Pulse, Eye Insertion, Activity, Respiration). CONCLUSION: This case was managed without any invasive procedures and demonstrates that treatment of TRAP sequence cases can be individualized considering clinical conditions, the size of the acardia twin and extent of placental venous anastomoses.

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.

Acardiac twinning: High resolution three-dimensional reconstruction of a low resistance case.

BACKGROUND: Acardiac twinning is a rare anomaly of monochorionic twin pregnancies. Acardiac fetuses lack a functional heart but are passively perfused by arterial blood from their pump co-twin. Although four acardiac morphological types have been classified, the various paths of anatomical and circulatory acardiac twin development, and the potential influence of acardiac size and perfusion flow as possible predictors of pump twin morbidity and mortality are poorly understood. This report presents the first high resolution three-dimensional reconstruction of the vasculature of an acardiac twin by cryomicrotome imaging. CASE: A small, approximately 7.5-cm-diameter ball-shaped acardius amorphous of 30 5/7 weeks had caused pump twin cardiac decompensation that necessitated an emergency cesarian section. The pump twin survived well. The acardiac body had a partially intact vascular system with large diameter arteries and veins and multiple zones that appeared devoid of perfusion. The three-dimensional reconstruction showed neither recognizable organ structures nor identifiable blood vessels except for the umbilical artery and vein. CONCLUSION: Our case showed a small acardiac mass with large diameter vessels and consequential low outflow resistance that caused pump twin complications. This indicates that the development of a method that allows pump twin prognosis is likely more successful if based on the use of acardiac versus pump twin perfusion flows than on body volume ratios.

Early vs late intervention in twin reversed arterial perfusion sequence.

OBJECTIVE: To compare two different management approaches in prenatally diagnosed twin reversed arterial perfusion (TRAP) sequence. METHODS: Retrospective analysis of all cases with TRAP sequence diagnosed in one center over a period of 10 years. Prior to 2010, all cases were managed expectantly until 19 weeks' gestation; thereafter, patients could choose either radiofrequency ablation (RFA) or expectant management (Group A). From 2010 onward all patients were offered interstitial laser at the time of diagnosis (12 weeks at the earliest) or expectant management (Group B). RESULTS: Forty cases were included in the study. In Group A, 23 cases were diagnosed at a mean gestational age of 19.9 ± 6.3 weeks. Sixteen patients were managed expectantly (13 survivors, 81%), while six underwent RFA at the time of diagnosis and one later in pregnancy (six survivors, 86%). In Group B, 17 cases were diagnosed at a mean gestational age of 16.4 ± 4.7 weeks. Six patients chose expectant management (five survivors, 83%) and 11 had interstitial laser therapy at the time of diagnosis (eight survivors, 73%). The loss rate of the pump twin was not significantly different between Group A and Group B (three of 23 vs four of 17; P = 0.3). In Group B the rates of preterm premature rupture of membranes (PPROM) and delivery < 34 weeks were significantly lower, and gestational age at birth as well as birth weight were significantly higher than in Group A. CONCLUSION: Despite the limitations resulting from its retrospective design, our study on management of TRAP sequence adds some evidence in favor of prophylactic intervention by intrafetal laser from 12 weeks onward.

"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 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.

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.

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.

Intestinal volvulus in the pump twin of a twin reversed arterial perfusion (TRAP) sequence after laser therapy at 18 weeks: a case report.

BACKGROUND: Twin reversed arterial perfusion sequence is a rare and potentially lethal condition affecting approximately 1% of monochorionic twin pregnancies and 1 in 35,000 pregnancies overall. An apparently normal (pump) twin perfuses its severely malformed cotwin with deoxygenated blood via retrograde flow in direct arterioarterial anastomoses between the umbilical arteries of each twin. Fetal intestinal volvulus is a rare condition usually manifesting after birth. We report a unique case of twin reversed arterial perfusion sequence in association with intestinal volvulus in the surviving pump twin. CASE PRESENTATION: A 32-year-old Hispanic primigravida was referred to our clinic after a fetoscopy procedure of laser photocoagulation of anastomoses at 18 weeks of gestation. Follow up scans in the ex-pump twin revealed dilated bowel loops and a typical "whirlpool sign" at 26 weeks of gestation, and intrauterine intestinal volvulus was suspected. At 29 weeks of gestation, preterm premature rupture of membranes occurred, and an emergency cesarean section was performed. The newborn was diagnosed in the early neonatal period with intestinal perforation. The diagnosis was postnatally confirmed by surgery and histopathology. CONCLUSIONS: The type of fetal intervention and late gestational age of the procedure increase the risk of complications. This case alerts health providers to be vigilant in the follow-up of patients with complicated monochorionic pregnancies.

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.

Acardius anceps with neck cyst and cleft palate: Three dimensional skeletal computed tomography reconstruction with discussion of the literature.

Acardiac twinning is a rare anomaly of monochorionic twin pregnancies. Acardiac fetuses lack a functional heart but are passively perfused by arterial blood from their pump co-twin causing the acardiac body to be hypoxemic. In this report, we present an acardius anceps, therapeutically laser separated from its pump twin at 16 weeks. The healthy pump twin and macerated acardiac body were born at 40 3/7 weeks. A three dimensional (3D) reconstruction was made by CT images, showing cranial bones, spinal column, pelvis and lower extremities but absent arms. A cyst in the neck of the acardiac twin was identified by postnatal sonography; this was also described in four literature cases, and was additionally observed by us in two other acardiac twins. Median cleft palate was identified by oral cavity inspection but undetectable in the reconstruction. In the literature, we found 21 other acardiac anceps twins with a cleft palate. From the two larger published series, with 12 clefts in 21 acardiac anceps twins, a cleft palate occurs in over 50% during acardiac twinning. Our first hypothesis is that acardiac fetuses develop an oral cleft palate when acardiac onset starts prior to 11 weeks, because 11 weeks includes the period of embryonic oral cavity formation, and no cleft occurs when onset starts later than 11 weeks. Our second hypothesis is that cysts and cleft palates are more common in acardiac twins than currently known, likely reflecting that acardiac bodies are hypoxemic and that hypoxia contributes to the development of both cysts and clefts.

Complex multigestational anomalies.

The increase in multiple gestation pregnancies has resulted in significant health care implications for both mother and child. Our ability to diagnose and intervene on an at-risk multi-gestation pregnancy has dramatically improved. It is important for the pediatric surgeon to be equipped with a basic fund of knowledge concerning these pregnancies. An understanding of amnionicity and chorionicity will equip the practitioner with the ability to identify which pregnancies are at risk for specific complications. This article highlights multi-gestation pregnancies that are monochorionic (single shared placenta) and can be complicated by twin-twin transfusion syndrome (TTTS), twin reversed arterial perfusion (TRAP) sequence, twin anemia polycythemia sequence (TAPS), or selective fetal intrauterine growth restriction (sIUGR). The risk of fetal demise is significant in these pregnancies. Understanding recommended surveillance and warning signs can alert surgeons to developing complications. Specialized fetal care centers possess the ability to intervene on these pregnancies in utero.

Ultrasonic identification of pump twin by dual-gate Doppler in a monochorionic-triamniotic triplet twin reversed arterial perfusion sequence before preventative radiofrequency ablation: a case report.

We performed a dual-gate Doppler examination for a twin reversed arterial perfusion (TRAP) sequence in a monochorionic-triamniotic triplet pregnancy at 16 weeks of gestation and were able to identify the pump twin by arterial pulse rate synchronicity. We performed radiofrequency ablation to coagulate blood flow in the acardius at 16 weeks of gestation without any postoperative complication. At 29 weeks of gestation, we performed a cesarean section due to preterm rupture of the membranes and the patient delivered 1167/1237-g female neonates and a macerated acardius. Examination of the placenta revealed two thickened vessels from the pump twin to the acardius, which had been prenatally identified by dual-gate Doppler. This new technology launches the new field of noninvasive fetal identification for triplet TRAP sequence.

Perfusão arterial reversa gemelar: revisão da literatura / Twin reverse arterial perfusion: literature review

A perfusão arterial reversa gemelar é uma anormalidade rara que pode ocorrer em gestações gemelares monocoriônicas. Consiste em uma alteração na circulação fetoplacentária, com desvio de sangue de um dos gemelares para o outro, por meio de anastomoses arterioarteriais e venovenosas na superfície placentária e anastomoses arteriovenosas em áreas de circulação placentária compartilhada. O feto bombeador pode desenvolver insuficiência cardíaca devido ao aumento do débito cardíaco, e o feto receptor, perfundido por sangue pobre em oxigênio por meio do fluxo reverso, é severamente malformado, incompatível com a vida extrauterina. Este artigo apresenta o caso de uma gestação gemelar monocoriônica diamniótica, com manejo clínico conservador. O objetivo é relatar um caso de complicação rara de gestações monozigóticas e revisar condutas para diagnóstico e manejo adequado.(AU)

Twin reverse arterial perfusion is a rare abnormality that can occur in monochorionic twin pregnancies. It consists of an alteration in the fetal-placental circulation, with blood diversion from one of the twins to the other, through arterio-arterial and veno- venous anastomosis on the placental surface and arterio-venous anastomosis in areas of shared placental circulation. The pumping fetus may develop heart failure due to increased cardiac output, and the recipient fetus, perfused by oxygen-poor blood through reverse flow, is severely malformed, incompatible with extrauterine life. This article presents the case of a monochorionic diamniotic twin pregnancy, with conservative clinical management. The objective is to report a case of rare complication of monozygotic pregnancies and review procedures for diagnosis and adequate management.(AU)

Twin Reversed Arterial Perfusion: To Treat or Not?

Acardiac twinning or Twin Reverse Arterial Perfusion (TRAP)-sequence is a rare complication of monochorionic twin pregnancy. Whether to start elective or therapeutic treatment in TRAP-sequence is still controversial. In the present case, acardiac twin was not diagnosed till her delivery at 39 weeks. A healthy baby weighing 2.45 kg was delivered along with another amorphous mass (acardiac twin) of about 150 g which was attached to the placenta with a short and separate cord. As outcome of normal twin vary according to the growth of acardiac twin, frequent follow-up of the normal twin is required to look for the features of heart failure. Hence, the diagnosis of acardiac twin is essential in early pregnancy.

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.

Secuencia de perfusión arterial reversa en embarazo gemelar; coagulación de arteria nutricia. Reporte del primer caso en el país / Twin reversed arterial perfusion sequence; coagulation of the umbilical cord. A report on the first case in Uruguay / Seqüência reversa de perfusão arterial na gravidez gemelar; coagulação da artéria nutritiva. Relato do primeiro caso no país

Resumen: La secuencia de perfusión arterial reversa (TRAP) es una complicación muy poco frecuente y grave de los embarazos gemelares monocoriónicos. Generalmente ocurre cuando el corazón de un gemelo de apariencia normal sirve como bomba para uno o más gemelos dismórficos cuya cabeza, órganos torácicos y extremidades superiores no se desarrollan completamente o no se desarrollan en absoluto y, por lo tanto, carecen de actividad cardíaca. La arquitectura placentaria vascular anómala provoca un cambio en el flujo arterial hacia el gemelo acardíaco. Los mecanismos fisiopatológicos exactos que conducen a este fenómeno devastador no se conocen bien. Compartiremos el caso clínico de una paciente de 19 años, cursando un embarazo gemelar monocorial monoamniótico, en que realizamos diagnóstico de TRAPS, y realizamos la coagulación laser de la arteria nutricia del feto acárdico.

Abstract: Twin reversed arterial perfusion sequence (TRAPS) is rather an unusual and severe complication of monochorionic twin pregnancies. It usually occurs when the normal-appearance heart of a twin acts as a pump for one or more dysmorphic twins whose head, thoracic organs and upper limbs fail to totally develop or do not develop at all and thus, have no cardiac activity. The abnormal vascular architecture at the placenta changes the arterial flow towards the acardiac twin. The exact pathophysiological mechanisms that result in this devastating phenomenon are still unknown. The study presents the clinical case of a 19-year- old patient pregnant with monoamniotic, monochorionic twins and a diagnosis of TRAPS, treated by laser coagulation of the acardiac twin's umbilical cord.

Resumo: A seqüência reversa de perfusão arterial (TRAPS) é uma complicação muito rara e grave de gestações gemelares monocoriônicas. Geralmente ocorre quando o coração de um gêmeo de aparência normal serve como uma bomba para um ou mais gêmeos dismórficos cuja cabeça, órgãos torácicos e membros superiores não se desenvolvem totalmente ou não se desenvolvem e, portanto, não têm atividade cardíaca. A arquitetura vascular placentária anormal causa uma mudança no fluxo arterial para o gêmeo acardíaco. Os mecanismos fisiopatológicos exatos que levam a esse fenômeno devastador não são bem compreendidos. Descrevemos o caso clínico de uma paciente de 19 anos, portadora de gestação gemelar monocoriônica monoamniótica, na qual fizemos o diagnóstico de TRAPS e realizamos coagulação a laser da artéria nutritiva do feto acardíaco.