One twin is usually structurally completely normal. In this case, an acardiac twin pregnancy was misdiagnosed antenatally as a degenerated myoma but ended with delivery of a healthy baby. Twin reversed arterial perfusion trap syndrome is a rare condition 0. Sep 10, 2014 it should be noted that in one series of 24 cases, flow in the umbilical artery to the acardiac twin was shown to cease spontaneously in 21% of cases diagnosed in the first trimester without any intervention. The aa anastomosis controls the future of both the pump and the. Callen ultrasonography in obstetrics and gynaecology 4th ed.
It is a severe variant of twintotwin transfusion syndrome ttts. A twin reversed arterial perfusion trap sequence is rare and occurs in about 1% of monochorionic twin pregnancies and 1 in 35 000 deliveries. Case report twin reversed arterial perfusion sequence trap. An acardiac twin is a unique complication of monochorionic twinning, in which a normal pump twin perfuses the acardiac twin. Sep 19, 2005 in cases with a large acardiac twin or rapid growth of the acardiac mass, we recommend prompt intervention. Twin reversed arterial perfusion trap sequence is a rare complication of multiple pregnancy caused by defects in early embryogenesis.
A very rare, severe complication of monozygous twin pregnancy, which we recently dealt with in the obstetrics and gynecology department of the university emergency hospital bucharest, was a monochorionic monoamniotic twin pregnancy with acardiac twin trap. The acardiac twin usually has a poorly developed heart, upper body and head. Twinreversed arterial perfusion sequence is a rare complication of monochorionic twin pregnancy in which an anomalous acardiac fetus is hemodynamically dependent on its structurally normal pump twin. Twin reversed arterial perfusion sequence trap sequence.
Acardiac twinning is a rare obstetric condition unique to monochorionic twin gestation and the pump twin has high perinatal mortality. Acardiac fetuses lack a functional heart but are passively perfused by arterial blood from their pump co. Early diagnosis is essential for improving perinatal prognosis for the normal twin. Acardiacacephalic twin is a congenital anomaly that occurs in 1 of 35,000 pregnancies and 1% of monozygotic twin pregnancies. The acardiac twin is dependent upon the normal twin to provide circulation by means of vascular anastomosis. This case report presents an antenatally diagnosed monochorionic twin pregnancy, resulting in preterm delivery of a healthy, normal twin along with an acardiac co twin. Acardiac twin definition of acardiac twin by medical dictionary. Twin reversed arterial perfusion sequence trap sequence, also sometimes called trap syndrome is a condition that occurs only in identical twins that share a placenta monochorionic, in which one twin, lacking a functioning cardiac system, receives blood from the. Occlusion of umbilical artery in acardiac, acephalic twin.
The mortality rate of the pump twin is greater than 50%. An acardiac twin was diagnosed at 24 weeks gestation. The prenatal diagnosis of an acardiac fetus must be suspected in any multiple. The fourth type, and most seriously maldeveloped, is the acardius amorphus fetus, which retains virtually no cephalic or truncal organization at. Acardiac medical definition merriamwebster medical dictionary. Trap sequence acardiac twin texas childrens hospital. It requires blood pumped from the normal twin to keep developing, putting the pump fetus at risk of high output cardiac failure. Acardiac twin pregnancies are a rare but severe complication of monochorionic twinning, where the acardiac twin lacks cardiac function but nevertheless grows during pregnancy because it is perfused by the pump twin through a set of placental arterioarterial and venovenous anastomoses. The acardiac twin undergoes secondary atrophy and is nonviable. In twin reversed arterial perfusion sequence, occlusion of the vessel in the acardiac twin can be achieved by an embolisation coil, by bipolar cautery or by laser. An acardiac pump twin weight ratio 50% is associated with the development of polyhydramnios and preterm labour. Because the acardiac twins body is only perfused by the pump twins arterial blood, acardiac twins. Trap sequence is a rare complication of monochorionic twins. Case 1 was a 44 year old g3a2 mother with monochorionic diamniotic mcda twin pregnancy conceived after in vitro fertilization.
This was postoperatively diagnosed as an acardiac twin due to traps. The pump twin is at risk of heart failure and problems related to preterm birth. A 2015 study estimated the incidence of acardiac twin is 2. Jun 28, 2008 the pump or donor twin may develop cardiac failure because of the anomalous perfusion circuit. The twr is the wet weight of the acardiac twin divided by the weight of the normal twin. The second case of acardiac twin pregnancy with cytogenetic analysis of the acardiac showing the. Airp best cases in radiologicpathologic correlation. Polyhydramnios is significantly associated with the presence of renal tissue in the acardiac twin. Special forms in twin pregnancy acardiac twin twin. This case report presents an antenatally diagnosed monochorionic twin pregnancy, resulting in preterm delivery of a healthy, normal twin along with an acardiac cotwin. The possible perinatal sequelae of acardiac twin gestations include cardiac failure of the pump twin, polyhydramnios, and preterm delivery. Figure 3 the acardiac twin without well defined head and limbs. In the same series, 46% of cases had persistent flow to the acardiac twin at the time of planned intervention at 1618 weeks. Selective reduction of acardiac twin by radiofrequency ablation.
Twin reversed arterial perfusion trap sequence with. A diagnosis of acardiac, acephalic twin b was made and the pregnancy was followed with weekly ultrasound examinations until 33 weeks of gestation when premature labor with rupture of membranes occurred. Case report of autopsy and placental examination after. Abstract we report 2 cases of trap sequence diagnosed antenatally using three. Sep 15, 2016 both vv and acardiac resistances are significantly smaller than the aa resistance, based on respectively clinical data and acardiac blood volumetric growth. The acardiac twin is dependent upon the normal twin to provide circulation by means of. This is a rare, yet serious, complication seen in approximately 1 percent of twins who share a common placenta monochorionic where one twin is normal and the other is severely malformed generally missing the upper body, including the head, arms and heart. Successful intrauterine treatment with alcohol ablation in a case of.
For full access to this pdf, sign in to an existing account, or purchase an annual subscription. Perinatal outcome of fortynine pregnancies complicated by. Apr 25, 2003 acardiac twins are usually diagnosed during the antenatal period and almost invariably cause complications to the other fetus. 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. The acardiac twin undergoes secondary atrophy of the heart and dependent organs brain and often develops a characteristic set of anomalies including acardia and acephalus.
Consequently the pump twin provides the acardius with blood. One of the most important complications is twintotwin transfusion syndrome ttts, which is characterized by a shift of blood volume from the donor twin to the recipient twin through placental vascular connections. Acardiac anomaly is a rare complication of multiple pregnancies. Once treatment is indicated, the intrafetal approach to interrupt the vascular supply to the acardiac twin appears to be superior to cord occlusion techniques as it is simpler, safer and more effective. Preterm delivery, hydramnios and pump twin congestive heart failure in the normal twin were seen more commonly if the twr was above 70%. The twins blood systems are connected instead of independent. Pdf a case of trap sequence with immense acardiac twin. Twin reversed arterial perfusion trap sequence, is a rare. Special forms in twin pregnancy acardiac twin twin reversed. An acardiac twin in a multiple pregnancy initially develops normally and is a specific complication of monozygous multiple pregnancies. Acardiac twinning is thought to affect 1 in 100 monozygotic twin pregnancies and 1 in 35,000 pregnancies overall 2,3. The acardiac twin is not connected to the placenta but, rather, directly to the umbilical cord of the pump twin. Associated findings include the presence of a single umbilical artery 66% and chromosomal abnormalities in the acardiac twin 33%. In this report, we present an acardius anceps, therapeutically laser separated from its pump twin at 16 weeks.
The circulation of the acardiac twin is accomplished solely by the heart of the other fetus. Our simulations support clinical results which show that uvd ratios aid in the prediction of pump twin risk. It should be noted that in one series of 24 cases, flow in the umbilical artery to the acardiac twin was shown to cease spontaneously in 21% of cases diagnosed in the first trimester without any intervention. Antenatal diagnosis of acardiac, acephalic twin sciencedirect. A mass attached to the placenta next to that of twin was first noted on a scan performed at 11 weeks of gestation. Acardiac twinning twin reversed arterial perfusion sequence. Successful ablation of acardiac twin with histoacryl. Acardiac twin pregnancies are a rare but severe complication of monochorionic twinning. Intrauterine treatment for an acardiac twin with alcohol. Twin reversed arterial perfusion trap sequence or acardiac twinning is a very rare problem, occurring in approximately 1% of monochorionic twins mc, twins sharing one placenta. Twin reversed arterial perfusion syndrome trap or acardiac. An acardiac twin, also known a recipient twin, refers to the haemodynamically disadvantaged twin of a twin pair in the setting of twin reversed arterial perfusion trap sequence.
Trap sequence acardiac twin twin reversed arterial perfusion sequence. Surgical procedures may be hazardous to the mother. Acardiac twin or trap sequence is a rare complication of monochorionic twin pregnancies. Trap should be suspected in monochorionic twin pregnancies when one fetus appears anatomically. The acardiac acephalus fetus has no cephalic development at all.
Trap should be suspected in monochorionic twin pregnancies when one fetus appears anatomically normal and the other lacks apparent cardiac structures. In this case report we present a case of trap sequence with immense acardiac twin with favorable outcome, emphasizing the importance of ultrasound imaging. A case of trap sequence with immense acardiac twin in. The acardius anceps fetus has cranial structures andor neural tissue development. The acardiac twin develops multiple anomalies that make survival. Pdf trap sequence in an acardiac twin researchgate. We describe a novel approachthe insertion of a helical metal coil to induce thrombosis in the umbilical artery of the acardiac twinwhich immediately interrupted flow. An acardiac twin with a nearly normal external appearance and an almost normally developed brain, nourished by a surviving twin brother. Abstract acardiac twin pregnancy is a rare complication of monochorionic twinning caused by aterioarterial and venovenous placental anastomosis, leading to. Acardiac definition of acardiac by the free dictionary. Approximately 20% of all twin pregnancies are monochorionic. Jul 29, 2017 the acardiac twin usually has a poorly developed heart, upper body and head. Although antenatal diagnosis of the trap sequence has been reported by several authors, the pathogenesis.
Acardiac acephalic twinning is a rare anomaly in which a normal pump twin perfuses an acardiac twin, which results in twin reversed arterial perfusion sequence. Acardiac twin definition of acardiac twin by medical. The acardius acormus fetus demonstrates cephalic structures but has limited or no truncal development. Because of the increased cardiac work load, the normal twin can develop heart failure. It occurs only in multiple gestations associated with vascular anastomoses between the affected fetus and its co.
Since the acardiac twin would not survive, reported the surgeons in the massachusetts case, the incision for separation was performed far toward her side of the fusion plane so that her tissue could be used to achieve complete closure of the ventral defect in the surviving twin. Pdf acardiac twin is a rare complication of monozygotic twin pregnancies occurring in 1% of monochorionic twin gestations with an. Successful intrauterine treatment with alcohol ablation in. Trap sequence or acardiac twin ucsf fetal treatment center. The acardiac twin is a parasite, putting the pump fetus at risk of high output cardiac failure. An acardiac twin is a rare complication of multifetal pregnancy, in the literature reported at an incidence of 1% of monochorionic twin pregnancies, i. Acardiac medical definition merriamwebster medical. Herein we present the successful treatment of an acardiac twin with alcoholization as follows. Unterbrechung des umbilikalen blutflusses bei einem akardischen. One twin, called the acardiac twin or trap fetus, is severely malformed. The acardiac twin develops multiple anomalies that make survival difficult.
Twin reversed arterial perfusion syndrome trap or acardiac twin. Acardiac twinning is a rare anomaly of monochorionic twin pregnancies. Twin a, pump twin was structurally normal but had significantly increased amniotic fluid volume polyhydramnios, twin b was acardiac with blood flows seen in the paravesical arteries. The prenatal diagnosis of an acardiac fetus must be suspected in any multiple gestation in which. Jun 24, 2015 a very rare, severe complication of monozygous twin pregnancy, which we recently dealt with in the obstetrics and gynecology department of the university emergency hospital bucharest, was a monochorionic monoamniotic twin pregnancy with acardiac twin trap. A novel technique for selective reduction and obliteration of blood flow in the acardiac twin is described. Several methods have been proposed for intrauterine treatment of acardiac twin pregnancy and selective reduction of the acardiac twin with radiofrequency ablation rfa was recently reported to be minimally invasive and effective for intrauterine treatment of acardiac twin pregnancy4.
Interruption of umbilical blood flow in an acardiac twin by endoscopic laser coagulationk. Special forms in twin pregnancy acardiac twin twin reversed arterial perfusion trap sequence. Successful intrauterine treatment with radiofrequency. Robert 2 1department of anatomy, amala institute of medical sciences, thrissur, kerala, india. In the acardiac, acephalic twin malformation the normal cotwin is put at risk because of the extra cardiac workload. Trap sequence acardiac twin this is a rare, yet serious, complication seen in approximately 1 percent of twins who share a common placenta monochorionic where one twin is normal and the other is severely malformed generally missing the upper body, including the head, arms and heart. The other is an abnormal mass of tissue, consisting. Here we present a case of acardiac twin pregnancy in which. Twin reversed arterial perfusion sequencealso called trap sequence, traps, or acardiac twinningis a rare complication of monochorionic twin pregnancies. Twin reversed arterial perfusion sequence trap sequence, also sometimes called trap syndrome is a condition that occurs only in identical twins that share a placenta monochorionic, in which one twin, lacking a functioning cardiac system, receives blood from the normally developing twin called the pump twin. Acardiac twinning is caused by the development of arterioarterial vascular anastomoses between the umbilical arteries of monozygotic twins early in. The diagnosis of an acardiac twin in a monochorionic diamniotic pregnancy one normal male fetus and one acardius, and a dichorionic triplet normal female fetus was only made at 25 weeks.
Due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin, it is important to monitor the pump twin for signs of decompensation and, if indicated, intervene by interrupting vascular. Unlimited viewing of the articlechapter pdf and any associated supplements and figures. Acardiac twins are usually diagnosed during the antenatal period and almost invariably cause complications to the other fetus. 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.