TRAP sequence; case report

TRAP sequence is a syndrome with poor prognosis seen in monochorionic twin pregnancies at the rate of 1/100. There is an acardiac “nonviable” fetus with multiple anomalies in the TRAP sequence and a pump fetus feeding this fetus through vascular anastomoses in the placenta. Mortality for acardiac twins is 100%. The mortality of the pump twin is around 50%, and death may be generally due to high flow rate heart failure and sometimes prematurity caused by polyhydramnios. Here, we presented an acardiac acephalous type TRAP case that applied to the Obstetrics and Gynecology Clinic of Amasya University Sabuncuoğlu Şerefeddin Training and Research Hospital. The case was 30 years old. The patient had the first pregnancy and reached this pregnancy with the IVF method. She did not have any disease. During the measurement of NT, the fetus of acardiac acephalous type was detected. Laser ablation was performed at the outer center at 18 weeks. All subsequent follow-ups were done by our center. While the patient had 39 weeks and 2 days of pregnancy, the pregnancy was terminated by performing cesarean due to primipara breech arrival.

From monster to reversed perfusion

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.

An incidental rare finding of a TRAP sequence during a caesarean section: A case report

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.

Conservative management of a case of a cardiac anceps twin reversed arterial perfusion sequence misdiagnosed as vanishing twin: a case report

Twin reversed arterial perfusion (TRAP) sequence is a specific, rare and severe complication of monochorionic multiple pregnancy, which is characterized by one normal fetus (pump twin) and another with no cardiac activity and variable degree of deficient development of the head and upper limbs. The management of these pregnancies are a real challenge due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin. The aim of management is to maximize the chances of survival of the pump twin with some intervention. The preferred management suggested is elective ultrasound-guided laser coagulation or radiofrequency ablation of the umbilical cord vessels at 11-13 weeks when the survival is 70-75%. Delay in intervention until 16-18 weeks is associated with spontaneous cessation of blood flow in the acardiac twin in 60% of cases and in about 50% of these there is death or brain damage in the pump twin. However, pregnancies diagnosed late need to follow a tailored approach with expectant management. The authors report a case of TRAP twin sequence which on ultrasound was diagnosed as a case of vanishing twin at 20 weeks. Subsequently on follow up ultrasound, it was diagnosed as a trap sequence with the pump twin developing polyhydramnios at 30 weeks. She was counselled regarding the prognosis of the pump twin and she opted for conservative management. Weekly ultrasound and color doppler were done. The amniotic fluid index (AFI) decreased gradually at 33 and 35 weeks, there were no signs of congestive cardiac failure of the pump twin on Doppler studies and she had a spontaneous delivery of a healthy male child and an acardiac anceps fetus at 36weeks and 5 days. The perinatal mortality of a pump twin managed conservatively ranges from 35 to 55%. It is essential to diagnose the presence of trap sequence at an early gestational age through improved imaging techniques to plan a timely and effective intervention to salvage most of the pump twins.

Twin reversed arterial perfusion sequence in a monochorionic monoamniotic twin pregnancy: a very rare condition

Background Twin reversed arterial perfusion sequence (TRAP) is a very rare congenital anomaly. We present sonographic findings of TRAP sequence in the case of a multiparous woman with a monochorionic monoamniotic twin pregnancy who was referred to our unit for blood sugar control. Case presentation The patient had a history of co-twin demise at 13 weeks of gestation without appropriate fetal surveillance afterwards. We found a monochorionic placentation with a normal appearing pump twin, an abnormal appearing co-twin without obvious cardiac activity and reversed arterial flow toward instead of away from the anomalous acardiac fetus. Therefore, the sonographic diagnosis of TRAP sequence was confirmed. Conclusions We recommend considering the potential rare complications of monochorionic twin pregnancy which necessitates proper surveillance and intervention to monitor suitable growth of pump twin.

Twin reversed arterial perfusion in twin pregnancy

An interesting case of twin reversed arterial perfusion “TRAP” from a larger apparently normal pump twin with VACTERL abnormality; to smaller structurally abnormal twin in a monoamniotic monochorionic twin pregnancy resulting in fetal demise with subsequent termination of pregnancy. Defect in early embryogenesis leads to such rare multiple presentations.

Twin reversed arterial perfusion sequence: the heartless twin

To report a case of twin reversal arterial perfusion sequence and its management by means of laser coagulation of the vascular malformation in the placenta. Twin reversed arterial perfusion sequence is a rare form of twin to twin transfusion syndrome occurring primarily in Monochorionic monoamniotic twins. The prevalence is about 1 in 35,000 pregnancies. The significance of this condition is that there is a normal foetus and an acardiac foetus. The blood is shunted from the normal twin to the acardiac twin through vascular malformations in the placenta. The normal twin faces a high risk of both morbidity and mortality due to cardiac failure. A case of twin reversal arterial perfusion sequence diagnosed at 22 weeks following a target scan underwent laser photocoagulation and gave birth vaginally at 30 weeks without any complications. Early detection of this condition can lead to timely intervention and thereby improve the outcome. In Twin reversal arterial perfusion sequence, the normal or the pump twin has a high chance of mortality due to cardiac failure. As the size of the acardiac twin increases, there is a higher chance of mortality of the pump twin. There is a need for regular follow up with ultrasonography and foetal echocardiography along with early therapeutic interventions to ensure the survival of the normal twin. In our case, despite the large size of the acardiac twin, we had a successful pregnancy outcome for the normal twin due to timely intervention.