Implications twin reversed arterial perfusion sequence and twin twin transfusion syndrome can be m. Regression of the weight of the acardiac twin against its longest dimension l resulted in this equation for prediction of acardiac weight. After 32 weeks of gestation, only two pregnancies were complicated by perinatal mortality 4%. Preterm delivery, hydramnios and pump twin congestive heart failure in the normal twin were seen more commonly if the twr was above 70%.
The larger the acardiac compared to the pump twin the greater the risk. It should be suspected in all monochorionic, malformed fetuses with cystic hygroma, generalized edema, and an absent cardiac pulsation with a nonfunctioning heart even at term. The acardiac twin loses direct vascular connection with the placental villi and receives its entire blood supply from the pump twin. 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. Acardiac twin is a rare anomaly occurring in 1 in 35,000 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. Radiofrequency ablation rfa womens and infants health. Acardiac twin definition of acardiac twin by medical. This would then lead to death of the normal twin, unless it is delivered if it is far enough along in pregnancy. Two cases of first trimester diagnosis of acardiac twins by 3d4d ultrasound podobnik p, podobnik m, gebauer b, brlecic i, milicic i clinic podobnik, zagreb, croatia objective twin reversed arterial perfusion trap sequence occurs only in the setting of a monochorionic pregnancy and complicates 1% of. This rare pregnancy has 50% natural pump twin mortality but accurate risk prediction is currently impossible. Radiofrequency ablation rfa is a procedure where an alternating current in the radiofrequency range is transmitted via a shielded needle electrode, causing agitation heating and death in tissues. Trap twin reversed arterial perfusion sequence acardiac twinning is a rare anomaly that occurs in monozygotic monochorionic twins with an incidence of 1% and in 1 in 35,000 pregnancies overall.
The difference in estimated fetal weight between the pump twin and the acardiac acephalic twin is predictive of outcome. It occurs only in multiple gestations associated with vascular anastomoses between the affected fetus and its co. Posterior view 3 discussion the acardiac headless twin is a very rare malformation which is found in monozygotic monoamniotic pregnancies rarely biamniotics where acardiac twin is not vascularized by the placenta but by his twin through an umbilical artery against the. Figure 3 the acardiac twin without well defined head and limbs. Optimal management of acardiac twin pregnancies is controversial. The risk of the normal or pump twin going into heart failure and dying seems to depend on the size of the acardiac. Perinatal outcome of monoamniotic twin pregnancies.
Because the acardiac twins body is only perfused by the pump twins arterial blood, acardiac twins. Complications unique to mc twin pregnancy include twintwin transfusion syndrome, twin anemia polycythemia sequence, twin reversed arterial perfusion sequence, and selective fetal growth restriction. Twin reversed arterial perfusion trap sequence is a rare complication of monochorionic pregnancies. 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. The fetal treatment center combines the talents of specialists in pediatric surgery, genetics, obstetricsperinatology, anesthesia, cardiology, radiology, nursing, and neonatal medicine. The acardiac twin is not connected to the placenta but, rather, directly to the umbilical cord of the pump twin. Management of acardiac twins international journal of. Pdf acardiac twin is a rare complication of monozygotic twin pregnancies occurring in 1% of. The twins blood systems are connected instead of independent.
New technologies and large study groups have led to improved documentation of frequency and complications in twin pregnancies and longterm outcomes. Here we are presenting a primi gravida of 2426 weeks of gestation with twin gestation of monochorionic di amniotic type in preterm labor. Optimal method and timing of intrauterine intervention in. Congestive heart failure developed in 100% of pump twins when the weight of the acardiac twin exceeded 70% of that of the pump twin. Acardiac twins lack cardiac function but grow by perfusion of arterial blood from the pump twin. A parasitic twin, also known as an asymmetrical or unequal conjoined twin, is the result of the processes that also produce vanishing twins and conjoined twins, and may represent a continuum between the two.
Large acardiac twin hydropspoly in the pump twin increasing size of the acardiac twin consider rfa or bpc of the acardiac twin discordance for lethal fetal anomaly trap consider rfa or bpc of the anomalous twin dichorionic monochorionic no hydrops hydrops the fetal center twins prenatal care algorithm the fetal center. Acardiac twinning is thought to affect 1 in 100 monozygotic twin pregnancies and 1 in 35,000 pregnancies overall 2,3. 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. Our team of doctors, nurses, and social workers work together to coordinate all aspects of care from diagnosis to postoperative recovery and longterm followup. Browse all figures return to figure change zoom level zoom in zoom out. Its most distinctive feature, and the main focus of our attention, is the presence of a structurally normal pump twin, which provides a. The parasitic twin, little more than a torso with or without legs, receives its blood supply from the host twin by means of an umbilical cordlike structure, much like a fetus in fetu, except the. The pump twin weighed 1504 g and the macerated acardiac fetus 503 g.
Magnetic resonance imaging mri can be helpful in the diagnosis when ultrasound us is inconclusive med j malaysia vol 66 no 5 december 2011 511 the patient was seen two weeks later and the normal fetus showed no signs of cardiac failure a known complication from twinreversed arterial perfusion while the acardiac twin. In this case, an advanced telecommunication and teleconferencing system was able. Case report twin reversed arterial perfusion sequence trap. When the acardiustopump twin weight ratio exceeds 0. Artificial reproductive technologies have led to a pronounced rise in numbers of dizygotic and monozygotic twins. Selective reduction of acardiac twin by radiofrequency ablation. Twinning has fascinated human beings over the centuries. The acardius syndrome is a rare complication of monozygotic twin pregnancies, occurring in 35,000 births.
Special forms in twin pregnancy acardiac twin twin. The normal twin had mild complications and was discharged in good condition on day 47. An acardiac pump twin weight ratio 50% is associated with the development of polyhydramnios and preterm labour. A simple device for vascular occlusion of acardiac twins.
The acardiac monster is a form of monozygotic multiple gestation lacking a physiological heart and resulting in a bizarre fetal malformation which is sustained in utero by parasitic anastomoses to the circulation of a normal twin fetus. Trap sequence acardiac twin cord occlusion what is radiofrequency ablation rfa. A complication of monozygotic twin pregnancies in which one fetus develops normally. The twr is the wet weight of the acardiac twin divided by the weight of the normal twin. 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. The perinatal mortality rate 20 weeks of gestation through 28 days of life was 19%. Robert 2 1department of anatomy, amala institute of medical sciences, thrissur, kerala, india. There was a rudimentary vertebral column with 5 thoracic vertebrae and some spinal cord.
Twinreversed arterial perfusion trap sequence cincinnati. It occurs as a sporadic event as there have been no reports of family recurrence. Correlation between acardiac size and pump twin risk is secondary to the aa size but remains clinically usable. Autopsy of the acardiac twin confirmed the absence of cardiac and pulmonary tissues.
Twin reversed arterial perfusion sequence acardiac twinning, one of the most severe congenital malformations seen in humans, is unique to monochorionic placentation and occurs with a reported prevalence of 1% of monozygotic twins. Recent guidelines suggest prophylactic surgery before 18 weeks, suggesting 50% unnecessary interventions. Sep 15, 2016 pump twins therefore must continuously increase their cardiac output which may cause heart failure. Nov 20, 2017 twin reversed arterial perfusion trap sequence resulting in an acardiac twin is a unique complication of monozygotic twin pregnancy sharing a monochorionic and usually monoamniotic placenta, in which anastomoses connect the two fetoplacental circulations 1, 2. The management of a twin pregnancy complicated by an acardiac twin is a challenge. Acardiac medical definition merriamwebster medical. A total of 98 monoamniotic pregnancies were included. Twin reversed arterial perfusion sequencealso called trap sequence, traps, or acardiac twinningis a rare complication of monochorionic twin pregnancies. 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 twin reversed arterial perfusion syndrome is a rare occurrence and is noted to be about 1% of monozygotic twins and one in 35,000 deliveries. A case report abstract acardiac twins refer to a developmental anomaly unique to monochorionic pregnancies. Acardiac twinning twin reversed arterial perfusion sequence.
It is a severe variant of twintotwin transfusion syndrome ttts. The acardiac twin undergoes secondary atrophy and is nonviable. One twin, called the acardiac twin or trap fetus, is severely malformed. Acardiac twins refer to a developmental anomaly unique to monochorionic pregnancies. The acardiac twin usually has a poorly developed heart, upper body and head. The twin reversed arterial perfusion, or trap sequence, results in an acardiac twin, a parasitic twin that fails to develop a head, arms and a heart. Acardiac malformation also known as twin reversed arterial perfusion trap sequence, is a unique complication of monochorionic pregnancies.
If acardiac twin weighs less than 25 % of the weight of the donor, evolution is often favorable. 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. One of the twin was acardiac acephalous and another a pump twin with hydrops. When the estimated weight of the acardiac twin is over 70% of that of the pump twin, the prevalence of preterm delivery, polyhydramnios, and congestive heart failure of the pump twin is 90%, 40%, and 30%, respectively 6. Diagnosis and management of twin reversed arterial perfusion.
The reported fetalneonatal mortality of the pump twin is extremely high 5060%. Find, read and cite all the research you need on researchgate. Discussion acardiac twins, characterized by twin reverse arterial perfusion trap sequence is a rare complication unique to monochorionic twin gestation 1,2. The acardiac twin receives blood from an arterytoartery anastomosis, and therefore receives blood that has already circulated through the pump twin and is thus poor in oxygen and nutrients. Two cases of first trimester diagnosis of acardiac twins. Trap sequence is a rare complication of monochorionic twins. Acardiac medical definition merriamwebster medical dictionary. Fetoscopic cord ligation to prevent neurological injury in. Twin reversed arterial perfusion sequence trap sequence. Prenatal sonographic diagnosis of acardiac twin embedded. Acardiac twin is a rare complication of monozygotic twin pregnancies occurring in 1% of monochorionic twin gestations with an incidence of 1 in 35,000 births. Two cases of first trimester diagnosis of acardiac twins by. Acardiac twin or trap sequence is a rare complication of monochorionic twin pregnancies.
These factors may aid in the development of methods for pump twin prognosis and the promotion of selective clinical interventions. Early attempts were highly invasive and involved hysterotomy and removal of the acardiac twin 24. Since the richest blood arrives through the iliac arteries via umbilical arteries. It develops when the following conditions are present.
In the same series, 46% of cases had persistent flow to the acardiac twin at the time of planned intervention at 1618 weeks. Acardiac twins can be diagnosed antenatally on ultrasound by the absence of identifiable cardiac pulsation. Management options include conservative management, medical therapy, occlusion of connecting vessels and selective termination of the acardiac twin. The outcome is fatal for the acardiac twin with a 5075% mortality of the normal pump twin. Acardiac twinning, or the twin reversed arterial perfusion trap sequence, occurs in 1% of monozygotic twins, or 1 in 35,000 births. The acardiac twin is wholly dependent upon circulatory support from the pump twin, and its upper body and head are often poorly developed. Airp best cases in radiologicpathologic correlation. It requires blood pumped from the normal twin to keep developing, putting the pump fetus at risk of high output cardiac failure. Twin reversed arterial perfusion trap sequence occurs only in the setting of a monochorionic pregnancy and complicates 1% of monochorionic twin gestations, with an incidence of 1 in 35, 000 births. Although spontaneous dizygotic twinning is clearly associated with.
Acardiac twin syndrome is a rare entity complicating 1 in 100 monozygotic twin pregnancies and 1 in 35,000 births. 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. Twin, acardiac, acephalus luis izquierdo, md, james smith, md, george gilson, md, gerardo del valle, md, gary joffe, md, molly chatterjee, md, luis curet, md. Many of the bizarre defects are felt to be caused by low oxygen tension, and this. 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. Postmortem examination of the acardiac twins confirmed complete occlusion of the main intra. In the trap sequence, the acardiacanencephalic twin receives all of its blood supply from the normal, pump twin. It is a very rare complication that manifest as twin reversed arterial perfusion trap sequence as a. Twin reversed arterial perfusion sequence it is thought to be an example of extreme twin to twin transfusion. Jun 28, 2008 the pump or donor twin may develop cardiac failure because of the anomalous perfusion circuit. Special forms in twin pregnancy acardiac twin twin reversed.
Acardiac twin definition of acardiac twin by medical dictionary. Acardiac twinning twin reversed arterial perfusion. The previously reported incidence dating back to 1944 of 1. The shared placental circulation of monochorionic twins predisposes a surviving twin to devastating neurological injury in the event of cotwin demise. Pdf acardiac anomaly is a rare complication of multiple pregnancies. Twin reversed arterial perfusion syndrome trap, acardius.
The prognosis of healthy twin depends on the pulsatility index in umbilical artery infusing the fetus acardiac and size. It is a very rare complication that manifest as twin reversed arterial perfusion trap sequence as a result of vascular anastomoses at the placenta bed. A 32yearold female patient who was pregnant with twins presented for a regular prenatal checkup with her obstetrician at 25 weeks of gestation. Twin reversed arterial perfusion radiology reference. Acardiac definition of acardiac by the free dictionary. In twin reversed arterial perfusion trap sequence, the high risk of death for the normal pump twin 1 has led to the development of a wide range of intrauterine interventions to improve outcome. It is thought primarily to be due to increasing in cardiac demands of the pump twin in an effort to perfuse its acardiac sibling. It is caused by the development of arterioarterial vascular anastomoses between the umbilical arteries of monozygotic twins early in embryogenesis. Polyhydramnios is significantly associated with the presence of renal tissue in the acardiac twin. The ability to estimate the fetal weight of the acardiac twin is limited because of the absence of structures used in. The prenatal diagnosis of an acardiac fetus must be suspected in any multiple gestation in which cardiac activity cannot be documented sonographically in a growing fetus. Sonika mann, meenakshi barsaul chauhan, roopa malik, smiti nanda.
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