Twin-to-twin transfusion syndrome, vein of galen malformation, and transposition of the great arteries in a pair of monochorionic twins: coincidence or related association?

Dextro-transposition of the great arteries in one twin: case reports and literature review

BACKGROUND

Dextro-transposition of the great arteries (D-TGA) is a rare congenital heart disease, as it affects only 0.02-0.05% of live births. It is the second most common cyanotic heart disease following Tetralogy of Fallot. It has a male predominance. Fetal echocardiography is an optimal method for prenatal diagnosis of fetal D-TGA. In twin pregnancies, fetal D-TGA in one twin is very rare, especially in monochorionic-diamniotic twin pregnancies. Herein, we report a case of D-TGA in one twin in two dichorionic-diamniotic twin pregnancies and one monochorionic-diamniotic twin pregnancy from January 2018 to June 2021.

CASE DESCRIPTION

One twin with D-TGA was diagnosed by fetal echocardiography in the second trimester, and the co-twin was normal in all three cases. A multidisciplinary team provided extensive counseling regarding the D-TGA twin and the co-twin, and adequate perinatal management was provided. In cases 1, 2, and 3, the mothers underwent cesarean sections at 37 weeks + 2 days, 34 weeks + 5 days, and 36 weeks + 1 day, respectively. In case 1, which involved a female D-TGA neonate with birth weight 2,410 g, an emergent atrial septostomy was performed at 20 h after birth, and the neonate underwent atrial switch operation (ASO) 24 days after birth. In case 2, involving a male D-TGA neonate with a birth weight of 2,380 g, ASO was performed 24 days after birth. In case 3, involving a female D-TGA neonate with birth weight 2,240 g, ASO was performed 19 days after birth and delayed sternal closure was performed 4 days later. All six infants showed normal development during follow-up.

CONCLUSIONS

Early antenatal diagnosis of D-TGA in one fetus of a twin pregnancy is significantly important. A multidisciplinary team should carry individual evaluation and integrated management of the D-TGA twin and co-twin during the pregnancy and perinatal period. After birth, delayed ductus arteriosus closure in the D-TGA twins should be performed when necessary and individualized timings for arterial switch operation should be considered.

Review on the current treatment status of vein of Galen malformations and future directions in research and treatment

INTRODUCTION

Vein of Galen malformations (VOGMs) represent a rare pathologic entity with often catastrophic natural history. The advances in endovascular treatment in recent years have allowed for a paradigm shift in the treatment and outcome of these high-flow shunts, even though their pathogenetic mechanisms and evolution remain in part obscure.

AREAS COVERED

The overall management of VOGMs requires a tailored case-to-case approach, starting with in utero detection and reserving endovascular treatment for indicated cases. Lately, the advances in translational research with whole-genome sequencing and the coupling with cellular-level hemodynamics attempt to shed more light in the pathogenesis and evolution of these lesions. At the same time the advances in endovascular techniques allow for more safety and tailored technical strategy planning. Furthermore, the advances in MRI techniques allow a better understanding of their vascular anatomy. In view of these recent advances and by performing a PUBMED literature review of the last 15 years, we attempt a review of the evolutions in the imaging, management, endovascular treatment and understanding of underlying mechanisms for VOGMs.

EXPERT OPINION

The progress in the fields detailed in this review appears very promising in better understanding VOGMs and expanding the available therapeutic arsenal.

Double inferior vena cava in a monochorionic twin pregnancy with selective fetal growth restriction

Congenital anomalies of the infrarenal inferior vena cava (IVC) are well described in adult life, however, little information exists on their associations in fetal life. Here, we describe a case of a monochorionic diamniotic (MCDA) twin pregnancy complicated by selective fetal growth restriction (sFGR) with an incidental finding of a double IVC in one child. In fetal life, variants of the infrarenal IVC are strongly associated with heart defects, which might suggest haemodynamic alterations or genetic causes, even more so in our case with MCDA twins complicated by sFGR.

Growth patterns and associated risk factors of congenital malformations in twins

BACKGROUND

The rate of twinning continues to increase due to the combined effect of a rise in parental age and increased use of assisted reproductive technology. The risk of congenital anomalies in twins is higher than in singletons, but it is less well reported in relation to growth patterns. We focused to the auxological outcome of twin pregnancies when one or both of twins are affected by one or more malformations.

METHODS

We conducted a retrospective observational study reviewing the clinical charts of twins admitted in the period between January 2003 and December 2018 at the University Hospital of Palermo. The associations between malformations and anthropometric variables at birth were analyzed by comparison within each twin pair and regarding each variable as ordered difference between the two twins.

RESULTS

We studied data of 488 neonates (52% females) from 244 pregnancies. The rate of major congenital anomalies was 11%, affecting significantly the smaller twin (p = .00018; Odds ratio 3.21; 95% CI 1.65 6.59). Malformation class distribution was as following: genitourinary (24%), gastrointestinal (20%), cardiovascular (18.5%), musculoskeletal (11%), central nervous system (9%), syndromic (9%), ocular (5.5%) and diaphragmatic hernia (2%). The most predictive value, the Birthweight (BW) difference mean ratio in malformed versus not malformed neonates (- 0.31 vs 0.02; p = .0016) was distributed equally lower than zero in all malformed twins, except for those with congenital heart defects (p = .0000083). Microcephaly (head circumference < 2 standard deviation, SD) was present in 3% of symmetrically smaller twin, and severe microcephaly (< 3 SD) was present in 0.6%. We found that an intertwin BW discordance of 18% or greater identified 50% of neonates with microcephaly, but only 11% of malformed twins.

CONCLUSIONS

In case of one twin with a BW < 10th centile, a concomitant intertwin BW discordance ≥18% could reveal an increased risk for microcephaly but not for malformation. Lower values of BW, Ponderal index, Body mass index but above all negative value of BW difference mean ratio are associated with malformations in twin pairs.

Fetal stroke and cerebrovascular disease: Advances in understanding from lenticulostriate and venous imaging, alloimmune thrombocytopaenia and monochorionic twins

Fetal stroke is an important cause of cerebral palsy but is difficult to diagnose unless imaging is undertaken in pregnancies at risk because of known maternal or fetal disorders. Fetal ultrasound or magnetic resonance imaging may show haemorrhage or ischaemic lesions including multicystic encephalomalacia and focal porencephaly. Serial imaging has shown the development of malformations including schizencephaly and polymicrogyra after ischaemic and haemorrhagic stroke. Recognised causes of haemorrhagic fetal stroke include alloimmune and autoimmune thrombocytopaenia, maternal and fetal clotting disorders and trauma but these are relatively rare. It is likely that a significant proportion of periventricular and intraventricular haemorrhages are of venous origin. Recent evidence highlights the importance of arterial endothelial dysfunction, rather than thrombocytopaenia, in the intraparenchymal haemorrhage of alloimmune thrombocytopaenia. In the context of placental anastomoses, monochorionic diamniotic twins are at risk of twin twin transfusion syndrome (TTTS), or partial forms including Twin Oligohydramnios Polyhydramnios Sequence (TOPS), differences in estimated weight (selective Intrauterine growth Retardation; sIUGR), or in fetal haemoglobin (Twin Anaemia Polycythaemia Sequence; TAPS). There is a very wide range of ischaemic and haemorrhagic injury in a focal as well as a global distribution. Acute twin twin transfusion may account for intraventricular haemorrhage in recipients and periventricular leukomalacia in donors but there are additional risk factors for focal embolism and cerebrovascular disease. The recipient has circulatory overload, with effects on systemic and pulmonary circulations which probably lead to systemic and pulmonary hypertension and even right ventricular outflow tract obstruction as well as the polycythaemia which is a risk factor for thrombosis and vasculopathy. The donor is hypovolaemic and has a reticulocytosis in response to the anaemia while maternal hypertension and diabetes may influence stroke risk. Understanding of the mechanisms, including the role of vasculopathy, in well studied conditions such as alloimmune thrombocytopaenia and monochorionic diamniotic twinning may lead to reduction of the burden of antenatally sustained cerebral palsy.

Human genetics and molecular mechanisms of vein of Galen malformation

Vein of Galen malformations (VOGMs) are rare developmental cerebrovascular lesions characterized by fistulas between the choroidal circulation and the median prosencephalic vein. Although the treatment of VOGMs has greatly benefited from advances in endovascular therapy, including technical innovation in interventional neuroradiology, many patients are recalcitrant to procedural intervention or lack accessibility to specialized care centers, highlighting the need for improved screening, diagnostics, and therapeutics. A fundamental obstacle to identifying novel targets is the limited understanding of VOGM molecular pathophysiology, including its human genetics, and the lack of an adequate VOGM animal model. Herein, the known human mutations associated with VOGMs are reviewed to provide a framework for future gene discovery. Gene mutations have been identified in 2 Mendelian syndromes of which VOGM is an infrequent but associated phenotype: capillary malformation-arteriovenous malformation syndrome ( RASA1) and hereditary hemorrhagic telangiectasia ( ENG and ACVRL1). However, these mutations probably represent only a small fraction of all VOGM cases. Traditional genetic approaches have been limited in their ability to identify additional causative genes for VOGM because kindreds are rare, limited in patient number, and/or seem to have sporadic inheritance patterns, attributable in part to incomplete penetrance and phenotypic variability. The authors hypothesize that the apparent sporadic occurrence of VOGM may frequently be attributable to de novo mutation or incomplete penetrance of rare transmitted variants. Collaboration among treating physicians, patients' families, and investigators using next-generation sequencing could lead to the discovery of novel genes for VOGM. This could improve the understanding of normal vascular biology, elucidate the pathogenesis of VOGM and possibly other more common arteriovenous malformation subtypes, and pave the way for advances in the diagnosis and treatment of patients with VOGM.

Vein of Galen Aneurysmal Malformation in Monozygotic Twin

BACKGROUND

Vein of Galen aneurysmal malformation (VGAM) is a rare pediatric vascular malformation of the brain. Genetic backgrounds are not well elucidated. We report on a monozygotic twin with VGAM and his endovascular treatment, and the genetic analyses of the twins and their parents.

CASE DESCRIPTION

In a monochorionic, diamniotic pregnancy of a 28-year-old healthy woman, monozygotic twins were born by emergency caesarian section because of fetal distress of the smaller twin at 25 weeks' and 4 days' gestation. Although a postnatal cranial ultrasound failed to detect VGAM in the smaller twin, mild heart failure persisted. A brain magnetic resonance (MR) examination of this twin on day 82 revealed choroidal VGAM. The twin was treated successfully by two sessions of embolization at 6 and 8 months of age. An MR examination at 1 year showed minimal residual arteriovenous shunts. He developed normally similar to the normal co-twin, with a follow-up period of 1 year and 6 months. As for the affected twin, no germline mutation or copy number variations were identified in ENG, ALK1, SMAD4, BMPR2, PTEN, RASA1, KRIT1, Marcavernin, or PDCD10 through whole-exome sequencing (WES).

CONCLUSION

We have reported a rare combination of a monozygotic twin and VGAM and the successful endovascular treatment. Phenotypic discordance in monozygotic twins established early in embryogenesis could be attributable to environmental or epigenetic factors.

Perinatal outcome after selective feticide in monochorionic twin pregnancies

OBJECTIVE

To evaluate the incidence and risk factors of adverse perinatal outcome in complicated monochorionic twin pregnancies treated with selective feticide.

METHODS

This was a retrospective analysis of prospectively collected data from a consecutive, national cohort. All monochorionic twin pregnancies treated with selective feticide at Leiden University Medical Center between June 2000 and November 2011 were included. Obstetric and neonatal data were recorded. The primary outcome measure was adverse perinatal outcome, including fetal or neonatal demise or severe neonatal morbidity.

RESULTS

Data on perinatal outcome were obtained in all cases (n = 131). Overall perinatal survival rate was 67.2% (88/131). Median gestational age at delivery was 34 (interquartile range, 23-38) weeks. Neonatal mortality and morbidity rate in liveborn children was 4.3% (4/92) and 12.0 % (11/92), respectively. Severe cerebral injury was detected in three children. The overall incidence of adverse perinatal outcome was 41.2% (54/131). Median gestational age at occurrence of preterm prelabor rupture of membranes (PPROM) was 19.0 weeks and 32.0 weeks in cases with and without adverse perinatal outcome, respectively (P = 0.017). Liveborn children with adverse perinatal outcome were born at a lower median gestational age (29.0 weeks) than were children without adverse perinatal outcome (38.0 weeks) (P < 0.001).

CONCLUSIONS

The risk of adverse perinatal outcome after selective feticide is high and associated with low gestational age at occurrence of PPROM and low gestational age at delivery. Long-term follow-up to assess neurodevelopmental outcome in survivors is required.

Neonatal morbidity in twin-twin transfusion syndrome

Twin-twin transfusion syndrome (TTTS) is a severe complication of monochorionic twin pregnancies associated with high perinatal mortality and morbidity rates. Management in TTTS is a major challenge for obstetricians and neonatologists. Twins which are often born prematurely and may suffer from typical conditions associated with prematurity. In addition, surviving twins with TTTS are at increased risk for other complications including neurological, cardiovascular, renal and hematologic morbidity. Rare complications such as hypoxic-ischemic lesions to limbs or intestines and amniotic band syndrome have also been reported in TTTS survivors. This review focuses on the neonatal and pediatric mortality and morbidity in TTTS survivors, with special emphasis on the long-term neurodevelopmental outcome.