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Acardiac twin or twin reversed arterial perfusion (TRAP) sequence is a rare medical complication of Monozygotic twins. Taiwanese Obstetricians usually treat TRAP sequence conservatively. Occasionally, repeated amnio-reduction is performed to decompress the polyhydramnios caused by the TRAP sequence, even though there was no correction of the pathophysiologic mechanism. Radiofrequency ablation is a minimally invasive, percutaneous technique that can effectively obliterate blood supply to an acardiac twin to preserve and protect the pump twin. This recent technique has never been used before for the treatment of the TRAP sequence in Taiwan. This article reported the first-hand experience of acardiac twin management with RFA in Taipei Chang Gung Memorial Hospital.

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.

Twin-Reversed Arterial Perfusion(TRAP) sequence or Acardia twin refers to a unique complication of mono-chorionic twin pregnancy in which a twin with an absent or rudimentary non functioning heart (acardiac twin) is perfused by its co-twin (pumping twin) through a large artery to artery placental shunt, often accompanied by a vein to vein shunt. Here we discussed about a clinical case of TRAP sequence came in established preterm labour and its management. Keywords: Aberrant twinning, Acardia twin, Monochorionicity, Pumping twin.

Twin reversed arterial perfusion syndrome is a rare condition seen in monochorionic twin gestation. The incidence is 1 in 35000 births and 1 in 100 monozygotic twin pregnancies. It is a complication of twin pregnancy that occurs due to preferential blood flow within the vascular communication between the two fetuses. We hereby report a case of 24-year-old primigravida referred in view of twin pregnancy with demise of one twin. On serial ultrasound it was misinterpreted as missed abortion of one twin and twin papyruses in further scans. But the consistent growth of the demised fetus made us think of acardiac twin as a differential diagnosis. When she presented in labour to our hospital, she delivered an acardiac anceps fetus along with a normal fetus. Keywords: Acardiac twin, Twin reversed arterial perfusion, Monozygotic twins.

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.

Twin reversed arterial perfusion (TRAP) sequence is an anomaly of monochorionic twin pregnancies where one twin has an absent, non-functioning or rudimentary heart while the other twin may be normal. The condition occurs because of early development of arterio -arterial anastomoses between the umbilical arteries of twin foetuses that share a fused placenta. In this condition, the affected anomalous (acardiac twin) is perfused by the normal twin (pump twin) via an arterio-arterial anastomosis. The affected twin (acardiac twin) presents with malformations such as absent (acradia) or rudimentary heart, underdeveloped or missing head, upper body and limbs. As pump twin has to provide circulation to itself as well as the perfused twin, this increased burden to perfuse acardiac twin increases the risk of developing cardiac failure in pump twin. Here we present such a case of 22-year-old, which was diagnosed per operatively during caesarean section at department of obstetrics & gynecology, Rukshamaniben General Hospital, Ahmedabad. Keywords: TRAP sequence, TRAP syndrome, Choriongiopagus parasiticus, Acardiac twinning, Pump twin.

A human being born without heart and head, the acardius/acranius malformation, has been described since antiquity. Superstition and fear made it a mystical disorder, a sign of God’s wrath. The inquisition ruled that acranic infants should not be baptized and located the soul in the brain. Acardia was not associated with twin gestation until the reports of Méry (1720) and Winslow (1740) were published in Paris. In 1850, Meckel identified the pathogenetic mechanism as reversed perfusion due to large arterioarterial and venovenous anastomoses; he believed the heart would fail to develop or stop during development, and the acardiac fetus would be maintained by arterial perfusion from the pump twin. In 1859, Claudius articulated that after normal initial development, the heart degenerates when backwards flow in the aorta leads to thrombosis. Today, it is assumed that both mechanisms may exist. With the advent of prenatal ultrasound diagnosis and radiofrequency ablation of the acardiac twin’s circulation, it became possible to save the pump twin.

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

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

Multiple gestations, especially monochorionic twins are associated with unique complications such as twin to twin transfusion syndrome (TTTS) and twin reversed arterial perfusion (TRAP) sequence due to preferential blood flow within the vascular communications between the two fetuses. TRAP sequence is a rare complication of monochorionic twins. The authors describe two cases of acardiac twins, one diagnosed at 17 weeks and the other at 24 weeks. While the first one was lost to follow-up, the second pregnancy was managed expectantly with close antepartum surveillance and had a term vaginal delivery of a healthy baby, along with the acardiac twin which was non-viable. The pump twin continues to be developmentally normal.

Background Benirschke postulated that acardiac twinning occurs when markedly unequal embryonic splitting combines with arterioarterial (AA) and venovenous placental anastomoses. We tested this hypothesis by model simulations and by comparison of outcomes with 18 “pseudo-” (twin fetus with beating heart but otherwise with clear signs of an acardiac) and 3 “normal” acardiac cases. Methods The smaller/larger cell volume ratio at embryonic splitting becomes the smaller/larger embryonic/fetal blood volume ratio (a). From a, we derived nonpulsating blood pressures using normal values (larger twin) and normal values at an appropriate earlier gestational age (smaller twin). These unequal pressure sources were used in a linear resistance fetoplacental network to calculate umbilical venous diameter ratios. Acardiac onset occurs when the smaller twin has 50% left of its normal, singleton placenta. Comparison with clinical cases approximated a by crown-rump-length-ratio to the 3rd power. Input parameters are a and the AA-radius at 40 weeks. Results Acardiacs can be small or large, can occur early or late, earlier at smaller a and larger AA, with larger umbilical venous diameter ratios at smaller a and smaller AA. Comparison with the 21 clinical cases was good, except for 2. Conclusion Our analysis supports Benirschke's hypothesis. The smaller twin has to share its placental perfusion with the larger twin, which is a novel finding. The AA size is essential for the future of both fetuses but complicates easy understanding of (pseudo-)acardiac clinical presentations. Late acardiac onset occurs infrequently. Using nonpulsating circulations may have caused our extensive predictions of late onset. An improved model requires including hypoxemia in the smaller twin from chronic placental hypoperfusion. Birth Defects Research (Part A), 2016. © 2016 Wiley Periodicals, Inc.

Acardiac twin or Twin Reversed Arterial Perfusion sequence (TRAPS) is a unique and extreme complication seen in monochorionicmultifetal pregnancies. It comprises an often normal twin pumping deoxygenated arterial blood in retrograde through an acardiac, dysmorphic counterpart. Recently, a 2.6% incidence among monochorionic twins has been cited. For the pump/donor twin, mortality often exceeds 50% commonly from heart failure and prematurity. Acardiac twinning with a surviving donor twin has yet to be described in our setting. We describe a 28-year-old para 0+1 presenting in the second trimester with a twin pregnancy complicated by polyhydramnios of the donor viable twin and a non-viable recipient twin inadvertently diagnosed as a single fetal demise of a grossly malformed twin. The case was expectantly managed resulting in spontaneous preterm delivery and survival of the donor twin. TRAPS necessitates a high index of suspicion and a thorough sonographic evaluation in monochorionicmultifetal pregnancies.

Abnormal placental vascular anastomoses in monochorionic twins can give rise to a rare congenital anomaly known as Acardiac twin. With the advancement of antenatal care and ultrasonography many such cases are diagnosed early. However, in underdeveloped country like Nepal where early antenatal care coverage rate is low such cases may be diagnosed late. I report one such case of Acardiac acepahalus twin diagnosed during delivery.Janaki Medical College Journal of Medical Sciences (2015) Vol. 3 (2): 62-65

Background: Acardiac monochorionic twins lack cardiac function but grow by passive perfusion of the pump twin's deoxygenated arterial blood through placental arterioarterial (AA) and venovenous (VV) anastomoses and by hypoxia-mediated neovascularization. Pump twins therefore must continuously increase their cardiac output which may cause heart failure. Our aims were: to adapt our twin-twin transfusion syndrome model for acardiac twin pregnancies, to simulate pump and acardiac twin development, and to examine the model for early prognostic markers of pump twin survival. Methods: We used an infinite acardiac placental resistance, based on placental dye injection studies and simulations, suggesting the AA-Acardiac-VV series resistance determines the pump twin's excess cardiac output. Pump and acardiac development were expressed by the pump's excess cardiac output versus its normal value, represented by pump/acardiac umbilical venous diameter (UVD) ratios. Results: UVD ratios distinguish between AA-VV anastomoses that do and do not cause hydropic pump twins. Pump twins can handle relative larger acardiac perfusion at later than earlier gestation. Both VV and acardiac resistances are significantly smaller than the AA resistance, based on respectively clinical data and acardiac blood volumetric growth. Conclusion: Our simulations support clinical results which show that UVD ratios aid in the prediction of pump twin risk. The AA anastomosis controls the future of both the pump and the acardiac. Correlation between acardiac size and pump twin risk is secondary to the AA size but remains clinically usable. These factors may aid in the development of methods for pump twin prognosis and the promotion of selective clinical interventions.

Contains fulltext : 174200pub.pdf (Publisher’s version ) (Closed access) The Peter the Great Museum of Anthropology and Ethnography (Kunstkamera) in Saint Petersburg is the oldest museum in Russia. It keeps the remains of the anatomical collection of the world-famous 17th century Dutch anatomist Frederik Ruysch. This unique collection was bought and shipped in 1717 by Czar Peter the Great, and presently still comprises more than 900 specimens, a modest number of which concerns specimens with congenital anomalies. We searched for teratological clues in the existing collection and in all his descriptions and correspondence regarding specimens and cases he encountered during his career as doctor anatomiae and chief instructor of the surgeons and midwives in Amsterdam. A total of 63 teratological specimens and case descriptions were identified in this legacy, including some exceedingly rare anomalies. As it turns out, Ruysch was the first to describe several of the conditions we encountered, including intracranial teratoma, enchondromatosis, and Majewski syndrome. Although his comments pose an interesting view on how congenital anomalies were scientifically perceived in early 18th century Europe, Ruysch mostly refrained from explaining the causes of the conditions he encountered. Instead, he dedicated himself to careful descriptions of his specimens. Almost 300 years after his demise, Ruysch's legacy still impresses and inspires both scientists and lay men. (c) 2016 The Authors. American Journal of Medical Genetics Part A Published by Wiley Periodicals, Inc.

Twin reversed-arterial-perfusion sequence (TRAPS) is a rare and severe complication of monochorionic twin pregnancies. It usually occurs in the setting of monochorionic placentation, when the heart of a normal appearing twin serves as the pump for one or more dysmorphic twins whose head, thoracic organs, and upper extremities do not fully develop or do not develop at all and thus lack cardiac activity. Anomalous vascular placental architecture causes a shift in arterial flow towards the acardiac twin(s). The exact physiopathologic mechanisms that lead to this devastating phenomenon are not well known. We reviewed the maternal history and the surgical pathology reports of the fetuses and placentas of 13 different cases of TRAPS that were collected in a 23-year study period at a single institution. Herein we summarize the characteristic findings and illustrate specific mechanical feto-placental circulation issues that appear to be instrumental in the development of TRAPS.

Fetus acardius is a rare manifestation of twin reversed arterial perfusion and is a parasite due to vascular circulation from donor twin and lacks any resemblance to human embryos. Antenatal diagnosis is challenging as there are no well-defined features. We report here a case which presented as placental mass, the diagnosis of which was evident after delivery. Antenatal diagnosis, review of the literature, and differential diagnosis from the placental mass are discussed. A primigravida in the late third trimester had ultrasonography (USG) showing a 7 cm × 5 cm mass adjacent to the placenta. She had no complaints and fetal biometry was normal. She delivered a healthy baby; placenta showed an attached mass without identifiable fetal body or limbs, and was covered with skin having scanty hairs, which was identified as an amorphous fetus. Early diagnosis is possible by early USG; an acardiac amorphous fetus may present as placental mass. Characteristic feature on USG supplemented by magnetic resonance imaging may help in reaching a correct diagnosis and optimal management.

Multifetal gestation is often a high-risk pregnancy and especially the monochorionic twin pregnancy significantly contributes to fetal morbidity and mortality. Acardiac twinning, earlier known as chorioangiopagus parasiticus, is the most extreme manifestation of this condition. An acardiac twin is a rare complication of multifetal pregnancy, in the literature reported at an incidence of 1% of monochorionic twin pregnancies, i.e. 1 of 35,000 pregnancies. Often results from abnormal placental vascular anastomoses. This leads to twin reversal arterial perfusion with complex pathophysiology. Here authors present a case of acardiac twin pregnancy presented at 26 weeks with the ultrasonography report suggested?? Placental teratoma of size 11×11×13 cm with polyhydramnios as there was no reason to suspect something else as the picture described in the USG report with the polyhydramnios was fitting with the diagnosis of placental teratoma but as the scan was done at taluka place and the images provided were not clear authors decided to confirm the diagnosis from fetal medicine specialist as MTP was not the option for the patient as she was 28 weeks who confirmed that as a case of acardiac twin pregnancy and the case was managed accordingly.

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.

The twin reverse arterial perfusion (TRAP) sequence is a rare but serious complication of mono-chorionic multiple pregnancies in which the affected twin is reversely perfused from the healthy co-twin. The unaffected twin is at risk of cardiac de-compensation or complication related to polyhydramnios, preterm pre-labour rupture of membrane and preterm delivery. When the risk to the healthy fetus increases significantly, the management is to occlude the circulation to the acardiac twin. Here we report a case successfully managed with intra-fetal alcohol ablation at the mid-trimester.

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. Birth Defects Research (Part A) 106:213–217, 2016. © 2015 Wiley Periodicals, Inc.

Fetus Acardiacus is a very rare manifestation of twin gestation. This happens due to TRAP sequence. That is Twin reversed arterial perfusion. In this case an amorphous mass was seen on a routine antenatal scan and followed as there was a live twin also. The case report highlights the importance of careful scanning and follow up of twin gestation.

TRAP (Twin Reversed Arterial Perfusion) sequence is a rare complication of monozygotic twin pregnancy. It is due to defect in early pregnancy where there is defective arterial anastomosis in placenta. This results in a fetus with an absent heart (acardiac twin). This acardiac twin has a poorly developed upper body and head also. The pump twin (with a normal heart) is also at a risk of heart failure and problems related to preterm birth 1 .

Some specific cases of Acardiac twins observed in remote parts of India where foetuses have been found to have extra limbs jutting out of chest cavity or abdomen have been given the specific and an attractive name of god baby. The present case under discussion is one such case where an Acardiac twin with Acephalus in the parasitic twin and malformed donor twin with multiple congenital anomalies incompatible with life delivered spontaneously at a tertiary care centre.

BACKGROUND: Approximately 75% of monozygotic twin pregnancies share one monochorionic placenta where placental anastomoses are virtually always present to connect the two fetoplacental circulations. These anastomoses cause several serious complications such as acardiac twinning. Acardiac twins lack a functional heart but nevertheless show fetal growth because the normal pump twin perfuses the acardiac body through arterioarterial (AA) and venovenous (VV) anastomoses. The widely accepted 1% monochorionic acardiac incidence dates back to 1944 and the associated 1:35,000 pregnancies to 1953. Our aim was to update this analysis. METHODS: We accepted the 1% (actually 1.1%) monochorionic acardiac incidence due to lack of more precise data, included the recently observed 58% early cessation of acardiac development as well as consequences of assisted reproductive technology, and assessed the incidence of acardiac twinning under conditions of AA-VV anastomoses. RESULTS: Early acardiac monochorionic twinning increased from 1.1% to 1.1/(1-0.58) = 2.6%, from 1:35,000 to 1:9,500 to 11,000 pregnancies, depending on number and method of assisted reproductive technology, and occurs in approximately 1:8 AA-VV anastomoses-containing monochorionic placentas. CONCLUSION: Early acardiac twinning is not a rare event. The 1944-based 1% acardiac monochorionic incidence has a weak basis and could therefore be (much) larger. Knowing this incidence more precisely may contribute to our knowledge of embryonic splitting in unequal cell masses. Birth Defects Research (Part A) 103:641-643, 2015. (c) 2015 Wiley Periodicals, Inc.

Acardiac twinning or TRAP-sequence is a rare complication of monochorionic twin pregnancy. We present a case in which fetal demise of one fetus of a twin pregnancy had been wrongly diagnosed in the first trimester as a vanishing twin. This resulted in the unexpected occurrence of an acardiac twin in the third trimester, culminating in an acardiac twin with a birth weight higher than that of the normal twin. A review is presented on therapeutic opportunities including ligation of the umbilical cord under ultrasound or fetoscopy. This case report highlights the need for correct and early ultrasonographic diagnosis of chorionicity and detailed ultrasonographic follow-up of twin pregnancies.

Twin reversed arterial perfusion sequence (TRAP) is a rare complication of spontaneous Dichorionic triamniotic triplet pregnancy and only few cases are documented. We report a case of twin reversed arterial perfusion (TRAP) sequence in a dichorionic triamniotic triplet spontaneous pregnancy, which was diagnosed at 27 weeks of gestation by four-dimensional ultrasound and revealed. The acardiac twin with omphalocele and the pump twin with cleft lip and palate. It highlights the risk of monochorionicity-associated morbidity in dichorionic triamniotic triplet pregnancies and role of four-dimensional ultrasound for diagnosis of trap and congenital anomalies.

Background: Twin reversed arterial perfusion (TRAP) sequence is a rare anomaly of monochorionic twins involving artery-to-artery anastomoses resulting in a structurally normal “pump” twin that provides circulation to an acardiac twin in a retrograde fashion. Case: Herein we report a rare case of a triplet gestation (TrGA) consisting of two conjoined acardiac TRAP recipients and one surviving normal pump fetus. The TRAP recipients were discordant for their anomalies. We know of only three similar case reports from the literature. Conclusion: Characteristic ultrasound findings allow for the prenatal diagnosis of TRAP sequence and may allow prompt and appropriate treatment to improve the outcome of the pump twin.

The authors report management of a woman with an acardiac twin pregnancy complicated by preterm premature rupture of the membrane (PPROM) for more than two months after intrauterine treatment with bipolar cord coagulation at 24 weeks of gestation.

The development of an acardiac anomaly, one of the most severe human malformations, is a rare complication unique to monochorionic multiple pregnancies. In this condition, the primary malformation is the lack of a well-defined cardiac structure in one twin (the acardiac twin), which is kept alive by its structurally normal co-twin (the pump twin). The final diagnosis for a twin pregnancy with an acardiac twin may be established after the 9th week, when the cephalic extremity and limbs can be precisely determined. Direct signs that lead to the diagnosis of an acardiac twin include the absence of cardiac and fetal movements, difficult visualization of the trunk and cephalic poles, thickening of subcutaneous tissue and the presence of umbilical artery reverse flow towards the acardiac fetus mass. The pump fetus may demonstrate hydramnios, cardiomegaly and heart failure. Once an acardiac anomaly is diagnosed, both the acardiac and pump twins should be assessed to classify the pregnancy according to prognostic factors based on the size and growth of the acardiac twin and the cardiovascular condition of the pump twin. Assessing the extent of heart damage in the pump fetus is a key step in pregnancy management. There are two available options, either conservative or interventional, for the management of these pregnancies. Serial ultrasound surveillance is important for detecting any worsening of the condition, which may suggest the need for interventions to optimize the pump-twin's chance for survival. We performed a retrospective analysis of three cases of monochorionic twin pregnancies diagnosed with a twin reversed arterial perfusion (TRAP) sequence during the first and second trimesters. We compared our data with those offered by a review of the literature.

Patterns of malformations seen in autopsies may contribute to the understanding of their pathogenetic mechanisms. Two entities, acardiac twins (ATs) and amniotic band disruption complex (ABDC), have distinct patterns, indicating different mechanisms, namely vascular perfusion deficit and external disruption. With ATs and ABDC as model groups, this study was undertaken to see if other dysmorphic infants with the characteristic defects of these models formed distinct and numerically important groups. A total of 192 autopsies with nongenetic malformations was divided into groups including (1) those with defects found in the ATs but not in the ABDC, (2) those with defects found only in the ABDC, and (3) those with a mixture of exclusive defects from each model group. The cases followed the characteristic defects of ATs or ABDC in 20% (group 1) and 28% (group 2), respectively, forming 2 large and distinct groups; only 4% had mixed malformations (group 3). Group 1 had different characteristics from group 2 as a result of the frequent multiple malformations, often with congenital heart defects (CHDs), internal and inferior malformations. These cases were probably related to a vascular perfusion deficit. Group 2 had a majority of females and single, external, and superior defects, but it lacked CHDs and inferior malformations. These cases were likely due to external disruption. Two large and distinct groups of autopsies with nongenetic malformations were thus identified, and their mechanisms are proposed to be similar to those of the model groups.

The dissemination of minimally invasive in utero surgery reduced the mortality of twin reversed arterial perfusion sequence, but the mortality of expectantly treated surgical candidates remains high. A 26-year-old, non-parous, Japanese woman at 13 weeks of gestation had been diagnosed with twin reversed arterial perfusion sequence and was judged as a surgical candidate for radiofrequency ablation. However, she did not undergo surgery because of the anatomical location of the acardiac twin. At 18 weeks of gestation, the blood flow to the acardiac twin disappeared spontaneously. The pump twin began to demonstrate fetal growth retardation during the third trimester. The patient delivered a 1891 g female at term. We macroscopically identified the cause of the fetal growth retardation as velamentous insertion of the umbilical cord and microscopically diagnosed the acardiac twin with acardiac acephalus. We should give the same attention to the management of post–twin reversed arterial perfusion sequence as twin reversed arterial perfusion sequence itself.

Acardius is one of the most severe human malformations, a rare complication present only in monozygotic and monochorionic multiple pregnancies. In this disorder, the major defect is the lack of well-defined cardiac structure in acardiac fetus, whose irrigation is maintained through placental vascular anastomoses with the normal fetus, called fetal donor, thereby establishing a reverse arterial perfusion in the umbilical cord of the acardiac twin (TRAP sequence). The poor circulation leads to a state of hypoxia in the early stages of fetal development, causing structural abnormalities, with different phenotypes, which are classified as: Acardius acephalus, anceps, and acormus amorphus. We relate a case of an acardiac anceps fetus that interestingly was reported by the physicians to present spasmodic movements just after the delivery. Due to severe malformations observed in an acardiac twin by the time of delivery, it is likely that many cases go unnoticed or misdiagnosed. The pathological findings are briefly reviewed to provide an adequate post mortem diagnosis of acardiac fetus and placental examination.

Twin reversed arterial perfusion (TRAP) sequence is a rare and severe complication specific to monochorionic twin pregnancies, involving the presence of an acardiac twin and a structurally normal co-twin (pump twin). We report on the case of a33-year-old female with a biamniotic monochorionic twin pregnancy complicated with TRAP sequence and polyhydramnios. The patient underwent fetoscopic termination of the acardiac twin and at 34 gestational weeks (GW) was readmitted with aretroplacental hematoma. The patient gave birth through caesarean section to a living female fetus, weighing 1480 g. To the best of our knowledge, this is the first case reporting a twin pregnancy with TRAP sequence complicated with retroplacental hematoma.

TRAP syndrome is a rare complication of monochorionic twin pregnancy. It is characterized by the association of an acardiac twin with a healthy twin. The acardiac twin is a parasite who put the healthy twin at high risk of cardiac failure. We report a case in a 25-year-old Malagasy woman, primigravida, who had a consultation at gestational week 31 for significant dyspnea and a threat of premature delivery. Ultrasound scans discovered an acute polyhydramnios, fetus with anasarca and low cardiac activity, and a para-fetal mass. She gives birth to a male newborn and an acardiac twin without head an upper body. The first twin died short time after birth.

This paper suggests that during the time of the "splitting process" that produces monozygotic twins the number of cells may not be evenly distributed to the future twins. The outcome of this 'irregular division' may be the twin-to-twin transfusion syndrome and acardiac twins.

Acardiac parabiotic twinning, also known as a twin reversed arterial perfusion (TRAP) sequence, is a rare occurrence found only in monozygotic twin fetuses whose vascular systems are connected. The circulation of the acardiac twin is accomplished solely by the heart of the other fetus. Although antenatal diagnosis of the TRAP sequence has been reported by several authors, the pathogenesis remains controversial. This case was incidentally detected during routine antenatal sonographic examination at 29 weeks of gestation.

The risk of perinatal morbidity and mortality in twins is 3-7 times higher than in singletons. In comparison to dichorionic twins, monochorionic twins are at increased risk for perinatal mortality and serious morbidity. In both type of twins growth discordance can occur. Discordant growth of dichorionic twins could be due to differences in placental mass or differences in placental parenchymal lesions, whereas birth weight discordancy in monochorionic twins is caused by placental vascular anastomoses. In this review the different types of complications (acardiac twins, acute and chronic twin-twin transfusion syndrome) due to different combinations of vascular anastomoses are discussed in relation to a computer model developed to gain more insight into the development of the twin-twin transfusion syndrome. The angioarchitecture of 395 monochorionic twin placentas was studied. Mortality was highest in the absence of an arterio-arterial anastomosis (42%) and lowest in the presence of an arterio-arterial anastomosis (15%). If mortality occurred, pregnancies with double mortality usually had an arterio-arterial anastomosis. If pregnancies were complicated by one death, a veno-venous anastomosis is more likely to be present. In conclusion, monochorionic twin pregnancies are a high risk pregnancy with a high chance of both mortality and morbidity; placental characteristics are a major contributor to adverse outcome in these pregnancies.

Acardiac twin syndrome is a rare complication affecting monozygotic twins, where one twin fails to develop normally and completely. In this report, we present an acardiac fetus that was seen for evaluation at 26 weeks of gestation. Initial routine ultrasound examination suggested anomalies. The first detailed ultrasound demonstrated a normal fetus with appropriate growth plus an acardiac twin with a hypoplastic lower limb with subcutaneous edema and intestine-like organ near it. The pregnancy was followed with serial ultrasonography and spontaneous delivery occurred at term. A normal infant was born, and after delivery of the placenta, at the chorionic plate of the placenta there was a sac with diminished fluid, containing some loops of the intestine. A thin cord of one vascular channel was attached to the common placenta. In our literature review, this type of acardiac fetus has not been reported previously.

Twin reversed arterial perfusion (TRAP) sequence is a serious condition of monochorionic twin pregnancy, occurring in approximately one in 35,000 cases. First trimester treatment of TRAP sequence is controversial with higher incidence of procedure related complications. Present case demonstrates a TRAP sequence that was managed by intrauterine treatment with one-ml 100\% pure alcohol injection into the abdominal part of the umbilical artery and obliteration of the acardiac twin at 14 weeks of gestation. Antenatal follow-up was uneventful and elective cesarean section was performed at 39 weeks' gestation. Postnatal outcome of the pump twin was excellent at 30 months after birth. Early second trimester elective ablation by alcohol injection can be an inexpensive, alternative, and reasonable minimal invasive treatment option to prevent fetal loss of pump twin before mid and late second trimester in perinatology centers where intrafetal cord occlusive methods are not available.

A 30-year-old multipara was found to carry an acardiac acephalus twin in a monozygotic twin pregnancy at 24 weeks of gestation and was referred to us from a private clinic. A cardiac twinning, a rare congenital anomaly of monozygotic twin pregnancy, often results from abnormal placental vascular anastomosis. Acardiac acephalus is a acardiac twin lacking a head, though it may have arms; thoracic organs are generally absent, and disorganized & unidentifiable tissues take their place, which invariably leads to death of the "perfused" twin and an estimated 50% perinatal mortality rate in the "pump" twin, due mainly to premature delivery or congestive heart failure. Autopsy of the fetus showed abnormalities compatible with the maldevelopment of embryonic folding. Fetus had omphalocele, bilateral absent kidneys, dextrocardia, hypoplastic lungs, absent right radial bone, abnormally positioned ears and agnathia.

Resume Au premier trimestre, l’echographie de 12 semaines est capitale pour depister les anomalies chromosomiques par la clarte nucale, pour reconnaitre precocement des malformations graves, pour etablir le type du placenta (monochorial ou bichorial). La chorionicite determine les strategies de depistage et de diagnostic prenatal ainsi que de prise en charge obstetricale. Au deuxieme trimestre le depistage chromosomique par les marqueurs seriques est moins efficace et le diagnostic echographique des malformations est plus difficile que dans les grossesses monofœtales. Quand une anomalie grave existe chez un seul fœtus, il est possible d’interrompre selectivement la grossesse. Cette intervention, tres aleatoire quand le placenta est monochorial, est bien codifiee quand il est bichorial. Son risque est plus faible au premier trimestre, ce qui souligne l’interet d’un diagnostic prenatal precoce chez les jumeaux. Un placenta de type monochorial expose a des complications specifiques, comme le syndrome transfuseur-transfuse. Celui-ci peut etre traite par photocoagulation au laser dans les formes graves et precoces, ou par amniodrainage dans les formes les plus moderees.