Placental Vascular Anastomoses Research Articles

Evaluation of the success of fetoscopic laser coagulation in placental vascular anastomoses and the role of fetal vascular Doppler before laser treatment in twin-to-twin transfusion syndrome

Evaluation of the success of fetoscopic laser coagulation in placental vascular anastomoses and the role of fetal vascular Doppler before laser treatment in twin-to-twin transfusion syndrome

The effect of chorionicity on maternal and neonatal outcomes in triplet pregnancies

ObjectiveTriplet gestations are associated with increased maternal, fetal, and neonatal complications particularly early and extreme preterm delivery. Identifying and interrupting the preterm delivery cascade could prevent the fetal, neonatal, and long-term childhood complications. The shared circulation and placental vascular anastomosis are responsible for the occurrence of twin-to-twin transfusion syndrome, selective fetal growth restriction as well as the higher risk of morbidity and mortality observed in mono and dichorionic compared to trichorionic triplet gestations.Thus, the aim of this study was to determine the effect of chorionicity on maternal, fetal, and neonatal outcomes of triplet pregnancies as it has not been fully ascertained. Study designA retrospective population-based cohort study of 125 parturient with triplets' pregnancy who delivered at a single tertiary hospital. Results98 trichorionic and 27 dichorionic gestations were included. Maternal demographic and obstetric characteristics as well as pregnancy and postpartum complications were similar in the two study groups. The median gestational age at delivery was lower among dichorionic than trichorionic triplet gestations (median 31 vs 33 weeks, p < 0.046). Early (<32 weeks) and extreme preterm delivery (<28 weeks) were more prevalent in the dichorionic than the trichorionic group (early − 56 % vs 34 %, p < 0.038; extreme − 33.3 % vs 8 %, p < 0.002). We found no difference in fetal or newborns' complications and characteristics between the groups. However, the rate of neonatal death was significantly higher in the dichorionic compared to trichorionic triplet gestations (22 % vs 7 %, p < 0.038).A multivariate logistic regression model to determine the variables that contribute to early preterm delivery in triplet gestations showed that women who experienced a past preterm delivery had an independently higher risk for early preterm delivery in the triplet gestation (adj. OR 5.91, 95 % CI 1.16–30.03). Neither maternal age nor chorionicity were found to be independent risk factors for early preterm delivery. ConclusionsDichorionic triplet gestations exhibit a higher rate of early (<32 weeks) and extreme (<28 weeks) preterm delivery and are more prone to neonatal death compared to trichorionic gestations. Past preterm delivery is an independent risk factor for early preterm delivery in a triplet gestation.

Degree of leukochimerism with calf age in Angus-crossbred twin sets.

Twinning in cattle is infrequent and usually undesired. It can result in an increased occurrence of abortion and dystocia, reduced calf survival and a high likelihood of freemartinism in mixed-sex twins. Twin gestations are also commonly associated with the formation of placental vascular anastomoses (PVA) between twins. Through PVA they share blood, hormones (leading to freemartinism in mixed sex twins) and hematopoietic stem cells, which are the progenitors of white blood cells. The sharing of stem cells between twins can result in leukochimeric twin sets. These are twins that have white blood cells derived from both self and the co-twin owing to the fetal migration of hematopoietic stem cells from the extraembryonic mesoderm of the yolk sac to final sites like bone marrow and thymus. This study examined the degree to which this leukochimerism changes with age. DNA was extracted from hair bulbs containing mesenchymal dermal papilla to determine the individual's true genotype and blood samples were obtained at six time points from 1 week to 8 months of age to assess leukochimerism. Samples were genotyped using a medium density SNP chip, and quantitative estimates of allele frequency were determined using SNPs for which members of a twin set had alternative homozygous genotypes. The results indicate statistically significant changes in the proportion of self and co-twin with age and suggest that by 2-4 months of age the genotypic mix in white blood cells represents the hematopoetic stem cell population resident in the individual (i.e. permanently found in thymus and bone marrow).

Two Year Neurodevelopmental Outcome after Fetoscopic Laser Therapy for Twin-Twin Transfusion Syndrome: Comparison with Uncomplicated Monochorionic Diamniotic Twins.

Twin-twin Transfusion Syndrome (TTTS) represents a significant complication in monochorionic twin pregnancies, caused by an unbalanced shunting of blood through intertwin placental vascular anastomoses. Despite advances in fetoscopic laser surgery, TTTS is still associated with a high rate of cerebral injury. However, there are no studies comparing these pregnancies with uncomplicated monochorionic diamniotic (MCDA) twin pregnancies, establishing the baseline risk of neurodevelopmental impairment. The aim of this study is to evaluate the odds of neurodevelopmental impairment in MCDA twins who undergo fetoscopic laser surgery for twin-twin transfusion syndrome, in comparison to a cohort of uncomplicated MCDA twin pregnancies. This is a retrospective cohort study of children born from MCDA twin pregnancies at a single center between 2008 and 2019. A routine, standardized follow-up assessment was conducted at a minimum of 2 years after delivery. The primary outcome of this was a 2 year neurodevelopmental impairment. Neurological, motor, and cognitive development was assessed by using the revised Brunet-Lézine scale. 176 children met the enrolment criteria. Of these, 42 (24%; TTTS group) underwent fetoscopic laser surgery for TTTS during pregnancy, and 134 (76%; uncomplicated MCDA group) were uncomplicated MCDA pregnancies. The primary outcome was found in four children (9.52%) in the TTTS group and ten children (7.46%) in the uncomplicated MCDA group (p = 0.67, aOR 2.82, 95% CI 0.49-16.23). Major neurologic impairment was found in 2.38% after fetoscopic laser surgery and 1.49% in uncomplicated MCDA twins (p = 0.70, aOR 0.97, 95% CI 0.22-4.24). The data were adjusted by birth order, birth weight, and gestational age at birth. The outcome in MCDA twins who underwent fetoscopic laser surgery for TTTS is comparable to the outcome in uncomplicated MCDA twins. Our findings emphasize the need for long-term neurodevelopmental follow-ups in all children from monochorionic twin gestations.

Chorionicity-associated variation in metabolic phenotype of cord blood in twin

BackgroundMonochorionic (MC) twins present a higher incidence of unfavorable clinical perinatal outcomes than dichorionic (DC) twins, often in association with placental vascular anastomosis. In this study, we profiled the umbilical cord plasma metabolomes of uncomplicated MC and DC twin pregnancies and related these to several offspring outcomes, previously associated with birthweight.MethodsUmbilical vein blood samples were collected at birth from 25 pairs of uncomplicated MC twins and 24 pairs of uncomplicated DC twins. The samples were subjected to gas chromatography-mass spectrometry-based metabolomics. 152 metabolites were identified from the cord plasma samples of MC and DC twins. Partial least squares discriminant analysis and pathway analysis were performed to compare within DC/MC twin pairs and between DC and MC twins. A generalized estimating equation (GEE) model was utilized to explore the correlation between metabolic differences and birthweight discordance within and between twin pairs.ResultsOur study revealed clear differences between the metabolite profiles of umbilical cord plasma of MC and DC twins. Metabolite profiles in MC within twin pairs and DC within twin pairs were characterized by the differences in 2 − hydroxyglutaramic acid levels and nicotinamide levels, respectively. The metabolic pathways of GSH, tryptophan, and fatty acid metabolism, were significantly downregulated in MC twins compared to DC twins. In addition, the concentration of caffeine and decamethyl-cyclopentasiloxane (D5) was positively correlated with birthweight in MC and DC twins.ConclusionThis study demonstrated that the altered metabolites in umbilical plasma made contributions to the different chorionicities between uncomplicated MC twins and DC twins. The chorionicity of twins seems to affect the metabolic cross-talk between co-twin pairs and be related to birthweight discordance of twins.

Surveillance of pregnancy outcome of monochorionic twins at Tu Du Hospital

Background: Monochorionic twins are a high risk pregnancy and are associated with special complications that are unique to sharing a placenta and because of the hemodynamic imbalance caused by placental vascular anastomoses. Therefore, the outcome of monochorionic twins is still being researched and reported to looking for the best evidence to perform the optimal interventions.&#x0D; Objectives: To describe the outcome of monochorionic twins to determine the proportion of special complications. Moreover, exploring the rate of fetal death in uterus, premature delivery, the successful vaginal birth in complicated monochorionic twins after bipolar cord coagulation.&#x0D; Materials and Methods: Case series report of monochorionic twins which was managed pregnancy and delivered at Tu Du hospital between January 2018 and January 2019, comprised 166 cases with 81 complicated monochorionic twin pregnancies.&#x0D; Results: The series comprised 85 uncomplicated monochorionic twins (51.2%) and 81 complicated cases (48.8%) with 15% twin-twin transfusion syndrome (TTTS) and 28.3% selective intrauterine growth restriction (sIUGR). Nineteen cases of bipolar cord coagulation perfomed included seven TTTS, eight sIUGR, three cases with serious malformation, and one twin reversed arterial perfusion sequence (TRAP).&#x0D; Conclusions: TTTS and sIUGR are complications unique to monochorionic twins and diagnosed in the early stage after 23 week’s gestation. Bipolar cord coagulation is an effective procedure in complicated monochorionic pregnancies to improve pregnancy outcome.

Molecular Mechanisms Underlying Twin-to-Twin Transfusion Syndrome.

Twin-to-twin transfusion syndrome is a unique disease and a serious complication occurring in 10–15% of monochorionic multiple pregnancies with various placental complications, including hypoxia, anemia, increased oxidative stress, and ischemia-reperfusion injury. Fetoscopic laser photocoagulation, a minimally invasive surgical procedure, seals the placental vascular anastomoses between twins and dramatically improves the survival rates in twin-to-twin transfusion syndrome. However, fetal demise still occurs, suggesting the presence of causes other than placental vascular anastomoses. Placental insufficiency is considered as the main cause of fetal demise in such cases; however, little is known about its underlying molecular mechanisms. Indeed, the further association of the pathogenic mechanisms involved in twin-to-twin transfusion syndrome placenta with several molecules and pathways, such as vascular endothelial growth factor and the renin–angiotensin system, makes it difficult to understand the underlying pathological conditions. Currently, there are no effective strategies focusing on these mechanisms in clinical practice. Certain types of cell death due to oxidative stress might be occurring in the placenta, and elucidation of the molecular mechanism underlying this cell death can help manage and prevent it. This review reports on the molecular mechanisms underlying the development of twin-to-twin transfusion syndrome for effective management and prevention of fetal demise after fetoscopic laser photocoagulation.

Predictive values of first trimester ultrasound screening for twin-to-twin transfusion syndrome and selective intrauterine growth restriction in monochorionic twin pregnancies

Background: Monochorionic diamniotic (MCDA) twins are at significantly increased risk of perinatal morbidity and mortality due to shared placentation and the presence of inter-twin placental vascular anastomoses. Aim of the work: The main aim of this study was to validate first trimester ultrasound screening for twin-to-twin transfusion syndrome (TTTS) and selective intrauterine growth restriction (sIUGR) in monochorionic twin pregnancies using the triad of nuchal translucency (NT), cord insertion site and inter-twin discordance in fetal size. Summary: We have demonstrated that NT and CRL were significantly higher in TTTS group than sIUGR group. And difference in NT, CRL and cord insertion site was identified as predictive markers for sIUGR and TTTS.

Experience with different techniques of laser coagulation of placental anastomoses to relieve feto-fetal transfusion syndrome in monochorionic diamniotic twins

Introduction. In recent years, the problem of multiple fetuses has become particularly important, which is associated with a steady increase in the frequency of multiple pregnancies worldwide. The feto-fetal transfusion syndrome (FFTS) is a classic example of unbalanced functioning of placental anastomoses, which leads to transfusion between fetuses. The incidence of this syndrome in a group of monochorionic diamniotic twins ranges from 8% to 15% and, in the absence of timely diagnosis and intrauterine correction, leads to death of one or both fetuses in 70-100% of cases. The effect of different methods of intrauterine surgical correction of FFTS in monochorionic diamniotic multiple fetuses on perinatal outcomes is of scientific interest. Purpose of the study — to investigate the effect of different types of laser coagulation of placental anastomosis (LCPA) on perinatal outcomes in intrauterine surgical correction of FFTS. Materials and methods. Depending on the surgical technique used, women were divided into three groups: the total placental anastomosis coagulation method, Group 1 (58 pregnant women); the selective placental anastomosis coagulation method, Group 2 (67 pregnant women); the sequential selective laser coagulation of placental anastomoses, Group 3 (62 pregnant women). Results. We analyzed the results of intrauterine surgical correction of FFTS by different methods of laser coagulation of placental anastomoses in 187 women with monochorionic diamniotic type of placentation of II-IV degrees according to Quintero. We obtained statistically significant differences in many perinatal period indices depending on the LCPA method used. Discussion. Sequential selective LCPA has proven to be the most effective, safe, and promising technique for correction of FFTS. The data obtained indicate possible ways to improve pregnancy prolongation and fetal survival rates after the use of intrauterine surgical correction of placental vascular anastomoses. Conclusion. Sequential selective LCPA has proven to be the best technique to correct FFTS with the least perinatal losses and postoperative complications, as well as the highest efficacy.

Transplacental transfer of congenital B‐cell acute lymphoblastic leukemia to the maternal vasculature

To the Editor: Monozygotic twin infants with KMT2A-rearranged (KMT2Ar) acute lymphoblastic leukemia (ALL) demonstrate near-uniform disease concordance due to prenatal transfer of pre-leukemic cells via placental vascular anastomoses.1-4 However, despite several historical reports recognizing the presence of fetal nucleated cells in the maternal circulation during pregnancy,5 fetal–maternal dissemination of leukemic clones has not been reported. We present a neonate with congenital KMT2Ar-ALL with documentation of metastasis to the maternal decidual placental vessels without clinical consequence. A newborn infant born at 37 4/7 weeks gestation was found to have leukocytosis (white blood cells 72.1 × 103/μl) with 62% blasts characterized by convoluted nuclear contour, prominent nucleoli, and scant deep-blue cytoplasm. Flow cytometry revealed expression of HLA-DR, CD15, CD19, CD22, CD34, cytoplasmic TdT, and cCD79a, consistent with B-cell ALL. G-banding karyotyping analysis revealed t(4;11)(q21;q23) with a dominant clone (five metaphase cells) containing a (4;11)(q21;q23) translocation and a subclone (one cell) containing an additional copy of der(4). Placental microscopy demonstrated clusters of blasts in both chorionic surface (fetal) vessels and decidual (maternal) vessels (Figure 1). Fluorescence in situ hybridization (FISH) analysis showed these clusters to be positive for the KMT2A rearrangement in both fetal and maternal vessels. These findings indicate that malignant fetal cells had infiltrated the maternal placental vasculature. Unlike in older children and adolescents, the prognosis of ALL in the neonatal age group is dismal.6 Despite intensive therapy, our patient experienced a highly complicated clinical course with eventual decompensation from Enterococcus faecalis bacteremia and infectious rotavirus leading to death on day 47 of life. Notably, throughout the patient's nearly 7-week clinical course, his mother did not demonstrate any clinically apparent findings to suggest sequelae of transplacental leukemia cell transfer. The discovery of leukemia cells of shared clonal lineage between monozygotic twins with ALL supports the so-called “intraplacental metastasis hypothesis”1 and confirms the capacity for pre-leukemic cells to spread from one twin to the other.7 These pre-leukemic cells are thought to transfuse via monochorionic placental vascular anastomoses rather than across the placental membrane barrier itself. Although placental involvement of congenital neuroblastoma has been reported,8 numerous reports of pregnant patients with hematologic malignancies demonstrate a noteworthy absence of clinically apparent transplacental “metastases” to exposed neonates.9-12 For example, in a report of prenatally diagnosed maternal ALL with leukemia cells detected in the cord blood, these cells were efficiently cleared and did not result in leukemic engraftment in the neonate.13 In this report, numerous lymphoblasts characterized by the KMT2A rearrangement were observed in the decidual (maternal) placental blood vessels, suggesting substantial cross-placental infiltration or local proliferation following infiltration. Our findings suggest the capacity for pre-leukemic cells to circumvent the placental membrane barrier as an additional means of transplacental penetration. The absence of a clinical impact on maternal health suggests that infiltrated malignant fetal cells undergo extraplacental maternal immune clearance and do not result in clinical consequence to the exposed mother. The authors declare that there is no conflict of interest.

Perinatal and Long Term Outcome of Monochorionic Twins Complicated by Twin-Twin Transfusion Syndrome

Twin-twin transfusion syndrome (TTTS) is the most harmful complication of monochorionic twin pregnancies. Fetoscopic laser coagulation of placental vascular anastomoses represents the causative and first-line treatment for the disease. Substantial improvements in survival rates and long-term outcome have been achieved during the last 20 years of practice. This is due to improvements in antenatal detection of the condition, surgical skills and centralization in the referral fetal therapy unit, as well as postnatal intensive care and follow up programs. Major morbidity issues concern cardiologic, renal and cerebral functions and are mainly caused by intrauterine haemodynamic imbalances and prematurity. This review summarizes the current evidence on the prognosis of monochorionic twins survivors after TTTS treated by laser surgery, focusing on perinatal and long-term outcomes.

Foeto-foetal transfusion syndrome in dichorionic diamniotic twins: a clinical case

Background. Management of multiple gestation complicated by the foeto-foetal transfusion syndrome is among most intricate modern obstetric issues. The syndrome develops in 10–20% of monochorionic diamniotic twins leading to 80–100% mortality in one or both twins if left uncorrected, especially in early syndrome cases. Although foeto-foetal transfusion usually develops with monochorionic placentae, there are notable exceptions of vascular placental anastomoses reported with dichorionic monozygotic twins. The disease supposedly entails from an imbalanced blood interflow between dichorionic twins due to placental vascular anastomoses.Clinical Case Description. Patient S., 32 yo, visited perinatal diagnostics at the Territorial Perinatal Centre of the Children’s Territorial Clinical Hospital with a preliminary diagnosis: 22 weeks and 5 days’ pregnancy. Dichorionic diamniotic twins. Threat of extremely preterm birth. Two caesarean uterine scars. Gestational diabetes mellitus.Medical files: patient history, pregnancy calendar. Pregnancy was regularly monitored with main ultrasound foetometry, foeto-foetal transfusion dynamics control and Doppler velocimetry.Ultrasonographic signs of abnormal haemodynamics underlying the foeto-foetal transfusion syndrome were detected at the first scan at 11–13 weeks 6 days’ term as collar space thickening in one foetus. Hydramnios in one foetus and oligohydramnios in the other were diagnosed at 28 weeks’ gestation conclusively indicating the foeto-foetal transfusion syndrome. This evidence suggested the formation of placental anastomoses, which was confirmed morphologically in placenta examination.Conclusion. A timely diagnosis and correction of emerging complications allowed prolongation of pregnancy in hospital conditions to 33–34 weeks. Both boys were live-born with Apgar score 7–8.

Comparison of the ratio of placental territory discordance to birthweight discordance in placentas of monochorionic diamniotic twins.

The ratio of placental territory discordance to birthweight discordance was calculated in monochorionic diamniotic twin placentas. We then determined whether the ratio: (1) correlated with the overall diameter of the placental superficial vascular anastomoses and (2) was different in normal monochorionic diamniotic twin (normal MCDA), twin-to-twin transfusion syndrome (TTTS), and selective intrauterine growth restriction (sIUGR) pregnancies. A prospective study of MCDA placentas was conducted from April 1, 2016, to April 1, 2019, including three groups, normal MCDA (N = 49), TTTS (N = 38), and sIUGR (N = 52). Placentas were studied via dye injection. In the normal MCDA, sIUGR, and TTTS groups, the ratio positively correlated with the overall diameter of the placental superficial vascular anastomoses (Spearman's = 0.295, 0.619, and 0.530; p = 0.040, <0.001, and 0.001, respectively) and gradually decreased from normal MCDA to sIUGR and to TTTS (2.88 (0.34, 64.25), 1.70 (0.27, 4.52), and 1.03 (0.12, 15.17); p < 0.001, p = 0.016/<0.001/0.005, respectively). The placental territory discordance to birthweight discordance ratio is an effective index reflecting the overall vascular anastomoses in MCDA placentas.

Синдром анемии-полицитемии – современные подходы к диагностике и антенатальной коррекции

Twin anemia polycythemia sequence (TAPS) is a specific complication of the monochorionic multiple birth, which is based on chronic feto-fetal blood transfusion over placental vascular anastomoses, and the main clinical symptom is discordant fetal hemoglobin level in the absence amniotic fluid imbalance. Currently, there is no generally recognized consensus on the optimal treatment tactics. Dynamic observation, labor, intrauterine blood transfusion, selective fetocide, fetoscopic laser coagulation of placental vascular anastomoses are applied, although the latter is recognized by the majority of researchers as the most promising method for treating TAPS. There are disagreements in estimating the frequency of perinatal morbidity and mortality during pregnancy, complicated by the development of TAPS, and their real value has not yet been completely defined. Key words: intrauterine transfusion, Solomon method, monochorionic twins, twin anemia polycythemia sequence, fetoscopic laser coagulation

Intrauterine surgery: how far we have come in 30 years.

Intrauterine surgery: how far we have come in 30 years.

Twin-twin transfusion syndrome - a University Hospital experience with intrauterine treatment.

twin-to-twin transfusion syndrome (TTTS), defined by combination of polyhydramnios-oligohydramnios, is the most prevalent (5%-35%) of the abnormalities due to placental vascular anastomoses and the most lethal (80%-100% mortality) if untreated. Fetoscopic laser ablation of abnormal vasculature using the Solomon technique is the gold standard approach. It consists of interrupting the intertwin blood flow. to present our initial experience at the Fetal Surgery Service of the Hospital de Clinicas of the Federal University of Parana (HC-UFPR) and to compare our results with those reported in the literature. we conducted a retrospective analysis of pregnancies who had undergone laser ablation, assessing data on Quintero's staging, gestational age at diagnosis and at the time of the procedure, placental position, immediate post-procedure survival, and survival after the neonatal period. We then compared these data with the most recent data available in the literature. we analyzed ten TTTS cases. The diagnosis was performed before the 26th week of pregnancy (median 20.8 weeks) and treatment occurred in a median of 9.5 days later. The distribution by the Quintero's staging was of three cases in stage II, five in stage III, and two in stage IV. In 50% of the gestations, at least one of the fetuses survived through the neonatal period. the treatment of TTTS in the HC-UFPR had a positive impact in the survival of the affected fetuses, although the results were worse than the ones reported in the literature, probably due to the delay in referencing the patients to our service, leading to a prolonged interval between diagnosis and treatment.

Non-invasive dynamic observation of placental vascular anastomoses in monochorionic twins: Assessment using three-dimensional sonography combined with tomographic ultrasound imaging

IntroductionThree-dimensional (3D) sonography combined with tomographic ultrasound imaging (TUI) to observe placental vascular anastomoses in monochorionic diamniotic (MCDA) twin pregnancies was evaluated. MethodsWomen with MCDA twin pregnancies at a gestational age of 16–32 weeks were enrolled in this retrospective study. Placental anastomoses were detected using two-dimensional (2D) and 3D sonography. Two-dimensional data were obtained by color and spectral Doppler and 3D data with high-definition flow within the area between twins’ umbilical cord insertions. Volume post-processing using TUI mode identified anastomoses. Anastomotic findings on ultrasound were compared with fetoscopic surgery or postnatally injected placentas for diagnostic value. Anastomoses detection was compared between the two imaging modalities. ResultsSeventy-six twin pregnancies were analyzed: 11 selective intrauterine growth restrictions (sIUGR), 10 twin-to-twin transfusion syndrome (TTTS), and 55 without complications. Seventy-one twin pregnancies had arterio-arterial (AA) anastomoses and 75 had arterio-venous (AV) anastomoses. Three-dimensional sonography combined with TUI was more sensitive (87.3%) and accurate (88.2%) in detecting AA anastomoses than 2D sonography (74.6%, 76.3%, respectively; P < 0.05), but had comparable sensitivity for AV anastomoses. The specificity of both modalities for anastomoses was 100%. The detection rate of AA anastomoses by 3D modality was (40%) TTTS vs. (87.3%) normal (P < 0.05), but comparable (90.9%) for sIUGR. The detection rates of AV anastomoses (90%, 81.8%) in TTTS and sIUGR were comparable with (87.3%) normal (P > 0.05). DiscussionThree-dimensional sonography combined with TUI highlighted placental anastomoses and may be useful for the clinical diagnosis and therapy of MCDA twin complications.

FetNet: a recurrent convolutional network for occlusion identification in fetoscopic videos

PurposeFetoscopic laser photocoagulation is a minimally invasive surgery for the treatment of twin-to-twin transfusion syndrome (TTTS). By using a lens/fibre-optic scope, inserted into the amniotic cavity, the abnormal placental vascular anastomoses are identified and ablated to regulate blood flow to both fetuses. Limited field-of-view, occlusions due to fetus presence and low visibility make it difficult to identify all vascular anastomoses. Automatic computer-assisted techniques may provide better understanding of the anatomical structure during surgery for risk-free laser photocoagulation and may facilitate in improving mosaics from fetoscopic videos.MethodsWe propose FetNet, a combined convolutional neural network (CNN) and long short-term memory (LSTM) recurrent neural network architecture for the spatio-temporal identification of fetoscopic events. We adapt an existing CNN architecture for spatial feature extraction and integrated it with the LSTM network for end-to-end spatio-temporal inference. We introduce differential learning rates during the model training to effectively utilising the pre-trained CNN weights. This may support computer-assisted interventions (CAI) during fetoscopic laser photocoagulation.ResultsWe perform quantitative evaluation of our method using 7 in vivo fetoscopic videos captured from different human TTTS cases. The total duration of these videos was 5551 s (138,780 frames). To test the robustness of the proposed approach, we perform 7-fold cross-validation where each video is treated as a hold-out or test set and training is performed using the remaining videos.ConclusionFetNet achieved superior performance compared to the existing CNN-based methods and provided improved inference because of the spatio-temporal information modelling. Online testing of FetNet, using a Tesla V100-DGXS-32GB GPU, achieved a frame rate of 114 fps. These results show that our method could potentially provide a real-time solution for CAI and automating occlusion and photocoagulation identification during fetoscopic procedures.

Twinning and birth defects: Rachipegal heteropagal twins and acardiac twins

Twin pregnancies are associated with multiple birth defects. The increase in twinning was attributed to fertility treatments. Twins were supposed to be associated with increased risk of congenital malformations. Among the twins, monozygotic twins were associated with more malformations then dizygotic twins. Heteropagus conjoined twins are asymmetrical conjoined twins where one twin is normal and the other is anatomically incomplete and grossly defective, attached externally, with or without internal connection. Heteropagal Conjoined twins were classified based on the site of their union, and when the fusion occurs at the level of the spine it is called Rachipagal heteropagal twin. One of the most important complication of Monochorionic placenta is Twin to twin transfusion syndrome. The major major defect is in recipient twin there was lack of well developed cardiac structure, and the blood supply was maintained through placental vascular anastomosis with normal twin. This sequence was described as the twin reversed arterial perfusion ,also known as Acardiac Twinning. Here we are going to present two rare cases of Rachipegal Heteropagal twin and Acardiac twin.

Fetal cardiovascular alterations in twin-to-twin transfusion syndrome.

Twin-to-twin transfusion syndrome (TTTS) is the consequence of vascular anastomoses of the shared placenta of monochorionic twin pregnancies. Both circulating inter-twin blood flow and vasoactive mediators imbalance cause hypovolemia in the donor and hypervolemia in the recipient fetus. If left untreated, TTTS has a high perinatal mortality rate and adverse long-term outcomes mainly cardiovascular and neurological.The recipient has cardiovascular changes including atrioventricular valve regurgitation, diastolic dysfunction and pulmonary stenosis/atresia. The maladaptive response to vascular changes determines a constant decreased blood flow in the donor that permanently modifies the arterial structure leading to postnatal alterations in the vascular system. Fetoscopic LASER surgery of placental vascular anastomoses may disrupt the underlying pathophysiology and improves cardiovascular function with normalization of systolic and diastolic function within weeks after treatment.The impact of cardiovascular changes is relevant for the safety of the management of a TTTS case. The improvement of the perinatal survival after intrauterine surgery leads to viable infants with the longer-term sequelae. Therefore accurate quantification of cardiovascular involvement is essential for clinicians for pregnancy management but also for patient counseling about the potential treatment options the outcome.