Acardiac anomaly spectrum

Fetus Acardiac Amorphous Presenting as Placental Tumor: A Rare Case and Differentiating the Two

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.

A Taiwan's experience: A case report and review of literature of successful early intrauterine treatment with radiofrequency ablation in twin reversed arterial perfusion (TRAP) sequence

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.

‘TRAP-ped with an Acardius’: Case Series of Twin Reversed Arterial Perfusion (TRAP) Sequence and Review of Literature

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 sequence associated with decreased fetal cerebral vascular impedance

OBJECTIVES

Twin-reversed arterial perfusion (TRAP) sequence affects 1% of monochorionic twin pregnancies and is caused by abnormal vascular connections between a pump twin and an acardiac mass. The effects of abnormal vascular connections on cerebral vasculature in the pump twin are unknown. We hypothesize that abnormal cerebral vascular impedance, as assessed by the pulsatility index (PI), is present in pump twins and that fetal intervention alters cerebral impedance.

METHODS

Fetal echocardiograms performed between 2010 and 2013 in pregnancies diagnosed with TRAP (n = 19), recorded at presentation, and uncomplicated monochorionic twin pregnancies (controls, n = 18; 36 fetuses) were analyzed. In all subjects, the middle cerebral artery (MCA)-PI, combined cardiac output (CCO) and cardiothoracic ratio were calculated, and the values for cases and controls were compared.

RESULTS

The mean gestational age at the time of echocardiography was 20 weeks in both groups. MCA-PI was lower in TRAP cases than in controls (1.55 (95% CI, 1.47-1.64) vs 1.74 (95% CI, 1.65-1.82), respectively; P = 0.004). CCO in TRAP cases was mildly elevated for gestational age (199.7 (95% CI, 138.4-261.1) mL/min) compared with that of controls (131.4 (95% CI, 102.2-160.7) mL/min). In six TRAP cases with a second echocardiogram available, the mean MCA-PI increased after intervention, from 1.5 (95% CI, 1.3-1.7) to 1.8 (95% CI, 1.4-2.2).

CONCLUSIONS

TRAP pump twins have lower cerebral vascular impedance than do controls, suggestive of a brain-sparing effect. MCA-PI appeared to increase in a small group of pump twins after intervention. These findings suggest a fetal cerebral autoregulatory response to a high cardiac output state that begins to change after fetal intervention. The long-term implications for neurodevelopmental outcome warrant further study.

Acardiacus acephalus twinning associated with exomphalos major, high impeforate anus and hypospadias

We describe a case report of acardiacus acephalus twinning associated with exomphalos major in both twins. One twin survived, who in addition had an anorectal anomaly and hypospadias. This is the first reported description of this combination of anomalies.

Acardiac anceps: a rare congenital anomaly

Acardiac twin is a rare congenital anomaly and is exclusively associated with monochorionic twin pregnancies. The abnormalities occur due to abnormal communication between the two fetuses in the form of arterioarterial and venovenous communications, resulting in a grossly abnormal acardiac twin with reduction anomalies mainly of the upper body and gross oedema. Since no two acardiac twins are alike, this case report will add to the acardiac twin anomaly spectrum.

An acardiac twin with advanced brain development and a minor form of holoprosencephaly and intracerebral retina-like pigmented tissue: a case report and review of the literature

The development of an acardiac twin in a monochorionic multiple pregnancy is a rare and severe complication of abnormal placental vascular anastomoses. These malformed fetuses present with a very bizarre morphology and a plethora of different malformations. However, all acardiac twins show either a complete absence or an anlage of the heart. Cerebral development is usually poor. We report, according to our review of the literature, for the first time, a very unusual case of acardius with features of acardius amorphus and acormus (fused head and malformed axial skeleton without macroscopically detectable internal organs) with lobar holoprosencephaly and intracerebral pigmented retina-like tissue.

Cyclopia, aprosencephaly, and acardiac twinning: Is hypoxia-ischemia a unifying mechanism?

In a recent case of monochorionic diamniotic twinning we observed one twin with acardia, cyclopia, and aprosencephaly, an association not reported previously. In most cases of acardia, the development of tissues in superior regions of the body is disrupted severely, while inferior structures develop more normally. A common explanation for this disruption is hypoxia-ischemia due to twin reversed arterial perfusion (TRAP). In this condition, arterial-arterial and venous-venous anastomoses in the placenta permit twin-twin transfusion and reversal of blood flow in the umbilical vessels and aorta of the recipient twin. The heart is absent or severely deficient, either by secondary atrophy or possibly a more primary, though currently unknown, mechanism. As a result, cranial tissues are less likely to be perfused with oxygenated blood than caudal tissues. A host of craniocerebral anomalies are observed in acardia, including total absence of the head and brain, rudimentary brain, anencephaly, holoprosencephaly, neuronal migration defects, and near-normal brain. Hypoxia-ischemia could be an important factor in the disruption of tissues in the present case, although a more generalized process affecting heart, head, and brain cannot be excluded. The findings suggest that hypoxia-ischemia may play a role in the pathogenesis of some cases of holoprosencephaly and aprosencephaly. This mechanism has been underreported and requires additional investigation.

Acardiac twin presenting as fetus amorphous with an attenuated umbilical cord

Acardiac anomaly sequence is a rare malformation cluster occurring in the setting of monozygotic monochorionic twin pregnancies. In addition to an absent heart (acardia), variable degrees of somatic developmental disruption are present. We describe an extreme example of what we believe to be acardiac twinning, with almost complete absence of gross tissue organization but recognizable microscopic evidence of body-axis establishment and organ formation. The case is also notable for the absence of a grossly identifiable umbilical cord, with attachment to the placental vasculature by 2 vessels invested by amnion but without Wharton's jelly. We discuss the controversy regarding the requirement of an umbilical cord in the definition of acardiac twin and distinguish this case from placental teratoma.

Intrafetal radiofrequency ablation for twin reversed arterial perfusion (TRAP): a single-center experience

OBJECTIVE

The objective of the study was to review perinatal outcomes in pregnancies treated with intrafetal radiofrequency ablation (RFA) for twin reversed arterial perfusion (TRAP) sequence.

STUDY DESIGN

Perinatal outcome data from a quaternary care referral center were abstracted from a chart review of pregnancies with TRAP sequence treated in the midtrimester with umbilical cord RFA of the perfused twin.

RESULTS

Twenty-one pregnancies with TRAP sequence were evaluated. Two women had a pump twin demise prior to therapy, 1 with trisomy 21 declined treatment. Four of 20 were treated successfully with RFA but remain undelivered, and 1 was treated with fetoscopic cord coagulation. Twelve of 13 pump twins treated with RFA (94%) survived to 30 days of life. Mean preoperative cardiac combined cardiac output was 588 mL/kg and pump/twin ratio was 0.7 (range 0.4 to 1.1). The effect of RFA on postoperative cardiac output was variable (6-85%). The average gestational age at birth was 37 weeks (range 26-39 weeks).

CONCLUSION

Primary therapy with RFA is a successful modality for pregnancies complicated by TRAP sequence.

Acardiac acephalic twin gestation with transposition of great arteries in pump twin

We report here a case of twin reversed arterial perfusion sequence with transposition of great arteries in the pump twin. Color Doppler and fetal echocardiographic examination revealed an acardiac, anencephalic twin without upper limbs and a pump twin with transposition of great arteries. To our knowledge despite multiple anomalies reported in the acardiac twin, major anomalies, especially of a cardiac type are extremely rare and not reported in the pump twin, which maintains circulation. Management is directed at saving the pump fetus; therefore, we believe that during sonographic exam, emphasis should be placed on associated organ anomalies or complications that may hamper viability of the pump.

Tailored management of twin reversed arterial perfusion (TRAP) sequence

OBJECTIVE

To describe our management of pregnancies complicated by twin reversed arterial perfusion (TRAP) sequence.

METHODS

This was a retrospective study involving all cases of TRAP sequence referred to our fetal medicine unit in a 3-year period (2000-2002). Patients were routinely managed by repeat sonographic surveillance with sonographic anatomical evaluation and detailed echocardiography. Cases with signs of impending cardiac failure were treated by in-utero YAG-laser coagulation of the umbilical vessels of the acardiac twin.

RESULTS

Six cases were studied. Three patients in whom there were no signs of deterioration in the status of the pump twin, and in whom the acardiac twin was smaller than the pump twin, were managed conservatively. However, one of these with monoamniotic twins ended in intrauterine fetal death of the pump twin. The other two cases presented with spontaneous cessation of blood flow in the umbilical artery of the acardiac twin. Both delivered at term normal neonates whose follow-up revealed no signs of neurological sequelae. One case of quadruplet pregnancy (with TRAP sequence and two dichorionic twins) was treated by selective termination of the monochorionic twins. Two cases with signs of impending cardiac failure were treated by in-utero YAG-laser occlusion of the vessels in the acardiac mass. Both interventions had a favorable outcome.

CONCLUSIONS

Conservative treatment is suitable for milder cases of TRAP sequence in which the pump twin is the larger one. Cases in which the acardiac twin is larger have a poorer prognosis and should be treated by invasive intervention and cord occlusion.

Complications arising in twin pregnancy: findings of prenatal ultrasonography

Multifetal gestations are high-risk pregnancies involving higher perinatal morbidity and mortality, and are subject to unique complications including twin oligohydramnios-polyhydramnios sequence, twin-to-twin transfusion syndrome, acardiac twins, conjoined twins, co-twin demise, and heterotopic pregnancies. The purpose of this study is to describe the prenatal ultrasonographic and pathologic findings of these complications.