Prenatal genetic features and prognostic factors in monochorionic twins with twin reversed arterial perfusion sequence / 中华围产医学杂志

Objective:To investigate the prenatal genetic features and the factors influencing the prognosis of twin reversed arterial perfusion sequence (TRAPS) in monochorionic twin pregnancies.Methods:A total of 99 cases diagnosed with TRAPS by prenatal ultrasound in the First Affiliated Hospital of Sun Yat-sen University from July 1, 2007, to December 31, 2021, were included retrospectively. The prenatal genetic features of acardiac and pump twins were analyzed. Eighty-nine cases were followed up and divided into two groups: the expectation group ( n=45) and the intrauterine intervention group (all underwent radiofrequency ablation, n=44) and the pregnancy outcomes were compared between the two groups. After excluding eight cases without complete ultrasound data, the expectation group was further divided into two subgroups: the pump fetus survival ( n=28) and the pump fetus death groups ( n=9), and the survival subgroup was divided into the spontaneous arrest group ( n=16) and coexistence group ( n=12) according to whether or not the blood flow stopped spontaneously.The relationship between ultrasonic indexes and pregnancy outcome was compared between the groups. Chi-square test (or Fisher's exact test), univariate logistic regression analysis and receiver operating characteristic (ROC) curve were used to analyze the relationship between the estimated acardiac to pump twin weight ratio (A/P Wt) and the pregnancy outcome of the pump twin in the expectation group. Results:(1) The median gestational age at diagnosis of the 99 TRAPS cases was 16.4 weeks (13.3- 21.3 weeks) and 32% (32/99) were diagnosed in the first trimester. Most of the cases were monochorionic diamniotic pregnancies (72/99, 73%). The survival rate of the pump twins was 71% (63/89). (2) Chromosome karyotyping and/or chromosomal microarray analysis was performed in 19 acardiac twins and 82 pump twins. The detection rate of genetic abnormalities in the acardiac twins was higher than that in the pump twins [4/19 vs 5% (4/82), Fisher's exact test, P=0.039]. Chromosomal microarray analysis was performed in 54 pump twins with normal karyotypes and the results showed three (6%) with genetic abnormalities. (3) In the expectation group, the area under ROC curve for the prenatal A/P Wt were 0.913 in predicting pump twin death and 0.807 in predicting spontaneous cessation of blood flow in the cardiac twin, and the cut-off values were 0.24 (sensitivity: 88.9%, specificity: 96.4%) and 0.11 (sensitivity: 75.0%, specificity: 81.3%), respectively. The survival rate of pump twins with abnormal cardiac function after intrauterine intervention was higher than that of the expectant group [72% (18/25) vs 3/11, Fisher's exact test, P=0.025]. Conclusions:TRAPS can be diagnosed in the first trimester and commonly occur in monochorionic diamniotic pregnancies. The detection rate of genetic abnormalities in the acardiac twins is higher than that in the pump twins. Prenatal A/P Wt>0.24 indicates the death of the pump twin and prenatal A/P Wt≤0.11 suggests a high possibility of spontaneous cessation of blood flow in the acardiac twin. Radiofrequency ablation is an effective method for improving the prognosis of the pump twin with cardiac dysfunction.

Secuencia de perfusión arterial reversa gemelar (TRAP): reporte de caso clínico de manejo expectante / Twin Reverse Arterial Perfusion Sequence (TRAP): clinical case report of expectant management

TRAP describe la perfusión crónica de un gemelo acardíaco por un gemelo de bomba a través de canales vasculares entrelazados permeables. La secuencia TRAP ocurre en 1 de cada 35.000 nacimientos o en 1 de cada 100 pares de gemelos monocigóticos. Se diagnostica mediante los hallazgos ecográficos de un feto de desarrollo normal y una masa amorfa con frecuencia con partes fetales perceptibles. El Doppler color revela el flujo sanguíneo reverso hacia el gemelo acardíaco dentro de la arteria umbilical lo que lleva a las complicaciones típicas del cuadro. El manejo expectante es razonable en ausencia de características pronósticas deficientes. El propósito de este artículo es revisar los aspectos básicos y el estado actual de esta condición, haciendo énfasis en el diagnóstico y el manejo expectante.

TRAP describes the chronic perfusion of an acardiac twin by a pump twin through permeable interlocking vascular channels. TRAP occurs in 1 in 35,000 births or 1 in 100 pairs of monozygotic twins. It is diagnosed by ultrasound findings of a normally developing fetus and an amorphous mass often with noticeable fetal parts. Color Doppler reveals the reverse blood flow to the acardiac twin within the umbilical artery, leading to typical complications of the condition. Expectant management is reasonable in the absence of poor prognostic characteristics. The purpose of this article is to review the basic aspects and current status of this condition, emphasizing the diagnosis and expectant management.

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.

Secuencia perfusión arterial reversa: Reporte de caso / Twin reversed arterial perfusion sequence: A case report

Twin reversed arterial perfusion sequence is a complication of monochorionic twin pregnancies in which one twin that exhibits lethal anomalies, including acardia, is perfused by the other 'pump' twin via anastomoses between placental arteries. This results in growth and characteristic anomalies of the acardiac twin, and possible heart failure of the pump twin. The exact pathophysiological mechanisms that lead to this devastating phenomenon are not well known. It occurs in about 1% of monochorionic pregnancies and in one out of 35 000 pregnancies. Mortality is usually due to anemia and cardiac complications which can lead to cardiac failure, appear early during pregnancy and cause the death of the pump twin. We report a case of twin reversed arterial perfusion in a 28-year-old patient with 12 weeks monochorionic-diamniotic pregnancy that was referred for absent cardiac activity in one twin. Ultrasound showed an acardiac twin with flow reversal seen in the umbilical artery and umbilical vein and a normal second twin. At 28 weeks an emergency cesarean section was done due preterm labor and transverse situation of the second twin. The first twin was malformed and the second twin died two days later due to complications of prematurity. Accurate prenatal diagnosis of twin reversed arterial perfusion sequence is essential to improve the prognosis of this rare entity.

La secuencia de perfusión arterial reversa en gemelos es una complicación del embarazo gemelar monocoriónico, en la que un gemelo muestra anomalías mortales, incluyendo acardia, y es perfundido por el otro gemelo 'bomba' a través de anastomosis arteriales placentarias, produciendo el crecimiento y las anomalías características del gemelo acárdico, con posible insuficiencia cardíaca en el gemelo bomba. Los mecanismos fisiopatológicos exactos que conducen a este fenómeno devastador no son bien conocidos. Ocurre en aproximadamente 1% de los embarazos monocoriónicos y en 1 de cada 35 000 embarazos. La mortalidad se debe generalmente a anemia y complicaciones cardíacas que pueden conducir a insuficiencia cardíaca, que aparecen temprano durante el embarazo y causan la muerte del gemelo bomba. Se presenta un caso de perfusión arterial reversa en gemelos en paciente de 28 años de edad con un embarazo monocoriónicodiamniótico de 12 semanas quien fue referida por ausencia de actividad cardíaca de uno de los gemelos. La ecografía mostró un gemelo acárdico con reversión de flujo visto en arteria-vena umbilical y un segundo gemelo normal. A las 28 semanas se realizó una cesárea de emergencia debido a parto pretérmino y situación transversa del segundo gemelo, obteniendo el primer gemelo marcadamente malformado y un segundo gemelo vivo que murió dos días después de las complicaciones de la prematuridad. El diagnóstico prenatal exacto secuencia de perfusión arterial reversa en gemelos es esencial para mejorar el pronóstico de esta rara entidad.

Prenatal diagnosis of triplet pregnancy complicated by twin reversed arterial perfusion sequence through ultrasonography / 中华医学超声杂志（电子版）

Objective To explore the characteristics of prenatal ultrasound image of triplet pregnancy complicated by twin reversed arterial perfusion sequence (TRAPS) and improve early diagnosis of this rare fetal malformation. Methods Compare the ultrasound and pathological findings of 6 cases of triplet pregnancy with TRAPS fetus by prenatal ultrasound diagnosis and postnatal diagnosis from April 2001 to April 2017 in Hubei Maternal and Child Health Hospital, and summarize the characteristics of prenatal ultrasound images of TRAPS fetus. Results Sonographic findings of the six triplet pregnancy were as follows: (1) Acardiac fetus: all acardias were absence of heart and beat, with hypogenetic lower limbs, five with skin edema and lymphoedema, five were absence of fetal head while one with stunted head, one with hypogenetic upper limb, four with spin and abdominal cavity, four acardias had single umbilical artery and were supplied by umbilical artery draining towards the fetus, two cases showed no blood flow in umbilical artery and fetal body. (2) Pump fetus: all of the six cases with normal anatomical structure, two showed normal amniotic fluid volume while four showed polyhydramnios, three cases had prenatal cardiac dysfunction (one case survived, two cases of intrauterine demise). (3) The third fetal of the triplets (TRAP co-twin ): during the Prenatal ultrasound follow-up five fetus had normal morphology with normal heart function, one fetal with multiple malformations. Prognosis of the triplet pregnancy: one triplet cesarean delivery two normal boys, five triplets were of poor prognosis (four pump fetus of intrauterine demise, one pump fetal of premature death: one TRAP co-twin of intrauterine demise, two TRAP co-twins of premature death, two TRAP co-twins of induced labor), four acardia twins of intrauterine spontaneous blood blocking, two still birth. Fetal chorionic and amniotic membrane: four cases were dichorionic triamniotic triplet pregnancy, one case was monochorionic triamniotic triplet gestation, one case was monochorionic diamniotic triplet pregnancy. Six cases were confirmed by pathologic anatomy. Conclusion Triplet pregnancy complicated by TRAPS is a rare and severe multiple pregnancy complication, with its characteristic acoustic image characteristics, combined with color doppler, prenatal ultrasound has a high diagnostic value.

Anesthesia for Fetal Surgery: Twin Reversed Arterial Perfusion Sequence / 대한마취과학회지

It is important to consider the fetal, uteroplacental, and maternal issues when choosing anesthetic technique for fetal surgery. The twin reversed arterial perfusion (TRAP) sequence, or the acardiac anomaly, occurs in 1:100 monozygous multiple pregnancies and in 1:35,000 births. The TRAP sequence is characterized by placental vascular arterio-arterial anastomosis between twin fetuses, one an acardiac/acephalic twin that receives its blood flow from the normal pumping twin, thereby endangering the normal twin by high output cardiac failure. The acardiac twin is nonviable, and perinatal mortality in the pump cotwin exceeds 50% because of cardiac failure and prematurity. This can be managed by fetal surgery. We report on a patient with a 26-wk gestation complicated by an acardiac/acephalic fetus anesthetized for surgical umbilical cord ligation.