T. Y. T. Tan

Acardiac twin: a systematic review of minimally invasive treatment modalities.

This review of the literature aimed to determine pregnancy outcomes after minimally invasive treatment for occluding vascular supply to acardiac twins. A MEDLINE search was performed until 2002 using the terms ‘acardiac’, ‘acardius’, ‘twin reversed arterial perfusion (TRAP) sequence’ and ‘chorangiopagus parasiticus’ and 207 articles published in the English‐language literature were identified. These articles and the corresponding cited references in English were reviewed. We identified 32 reports involving 74 cases of acardiac twin treated by minimally invasive techniques. Seventy one cases were included for analysis including 40 treated by cord occlusion and 31 by intrafetal ablation. Cord occlusion was first attempted by embolization (n = 5), cord ligation (n = 15), laser coagulation (n = 10), bipolar diathermy (n = 7) and monopolar diathermy (n = 3). Intrafetal ablation was performed by alcohol (n = 5), monopolar diathermy (n = 9), interstitial laser (n = 4) and radiofrequency (n = 13). The overall median gestational ages at treatment and delivery were 21 (range, 14–28) weeks and 36 (range, 19–42) weeks, respectively, with a median treatment–delivery interval of 13 (range, 0–25) weeks. The overall pump twin survival rate was 76% (n = 54). Intrafetal ablation was associated with later median gestational age at delivery (37 vs. 32 weeks, P = 0.04) and higher median treatment–delivery interval (16 vs. 9.5 weeks, P = 0.02) compared with cord occlusion techniques. It was also associated with a lower technical failure rate (13% vs. 35%, P = 0.03), lower rate of premature delivery or rupture of membranes before 32 weeks (23% vs. 58%, P = 0.003) and higher rate of clinical success (77% vs. 50%, P = 0.02) than cord occlusion techniques. There were no statistically significant differences in terms of outcome between the subgroups of fetoscopic‐ or ultrasound‐guided cord occlusion techniques. This review suggests that intrafetal ablation is the treatment of choice for acardiac twins because it is simpler, safer and more effective when compared with the cord occlusion techniques. Copyright

Doppler for artery-artery anastomosis and stage-independent survival in twin-twin transfusion.

OBJECTIVE: Treatment selection in twin–twin transfusion syndrome is increasingly determined by disease severity. We investigated whether detection of arterio-arterial anastomoses predicts perinatal survival. METHODS: An artery–artery anastomosis was sought by Doppler and disease stage was determined in 105 cases of twin–twin transfusion syndrome at presentation, first treatment, and worst stage. Outcome measures were perinatal, double, and any (1 or more babies) survival rates. RESULTS: After exclusion of 10 noninformative pregnancies, perinatal, double, and any survival rates were 61%, 44%, and 77%, respectively. When an anastomosis was detected at each of the 3 time points, perinatal and double survival rates were higher than when one was not (at first treatment, perinatal survival 83% versus 53%, respectively, P = .003; double survival 78% versus 33%, P < .001). Perinatal and double survival (P ≤ .01) were poorer with more advanced stage, but any survival rates were not influenced by stage or anastomosis detection. Multiple logistic regression demonstrated that anastomosis detection at treatment increased the chance of perinatal (odds ratio [OR] 5.1, 95% confidence interval [CI] 1.6, 15.9) and double survival (OR 19.3, 95% CI 2.7, 138), independently of stage. For stages I–III at treatment, anastomosis detection predicted better perinatal (100% versus 63%, 100% versus 59%, and 83% versus 44%, respectively) and double survival rates (100% versus 52%, 100% versus 46%, and 78% versus 26%). Stage III, with anastomoses detected, had better perinatal (83% versus 63%) and double survival (78% versus 52%) than did stage I without detection. CONCLUSION: Antenatal detection of artery-to-artery anastomosis predicts higher perinatal and double survival in twin–twin transfusion syndrome, independently of disease stage. LEVEL OF EVIDENCE: II-3

Increased latency of absent end‐diastolic flow in the umbilical artery of monochorionic twin fetuses

To determine if absent end‐diastolic flow (AEDF) in the umbilical artery (UA) has a longer latency in monochorionic (MC) twin fetuses compared to singleton or dichorionic twin (DC) fetuses.

The implications for fetal outcome of an abnormal arrangement of the abdominal vessels

In a prospective audit of consecutive referrals for fetal echocardiography between 1997 and 2003, we documented all instances of an abnormal arrangement of the abdominal vessels. We then established the structure of the heart in these fetuses, noting any extra-cardiac associations, and the eventual outcomes. We found a cardiac abnormality in 572 of the 2,136 fetuses examined during this period (27 percent), with 16 (0.8 percent) having an abnormal arrangement of the abdominal great vessels. Mirror-imaged arrangement was found in 3, while the arrangement suggested right isomerism in 6, and left isomerism in 7. Of these 16 fetuses, 14 had cardiac malformations. Isomerism of the right atrial appendages was found in 7 fetuses, all with either a right-sided stomach or cardiac apex, and 6 with a common atrioventricular junction guarded by a common valve. Only 1 of these fetuses survived. Of the 3 fetuses with mirror-imaged abdominal great vessels, 2 also had mirror-imaged atrial arrangement, while the 3rd had isomeric right appendages. Only one of 7 fetuses with an abdominal great vein posterior to the aorta had bilateral left atrial appendages. The remaining 6 had usual atrial arrangement, with normal pulmonary venous connections in all but one, who had infra-diaphragmatic totally anomalous pulmonary venous connection. Of these fetuses, 2 had coarctation of the aorta, and 2 others had complex cardiac malformations resulting in neonatal death. One died in childhood from biliary atresia, and three are alive. Abnormal arrangements of the abdominal great vessels, therefore, were found in 0.8 percent of our total fetuses, and in 2.4 percent of those with cardiac malformations. Those with an abnormal arrangement of the abdominal vessels combined with an abnormal arrangement of the atrial appendages, however, made up only 0.5 percent and 1.6 percent, respectively. While screening for an abnormal arrangement of the abdominal vessels overestimated the incidence of left, but not right, isomerism of the atrial appendages, it did predict the presence of important extra-cardiac malformations that required urgent recognition and management after birth.

P298: Fetal left atrial isomerism?an important predictor of neonatal complications with simple detection at standard abdominal biometry

pregnancy a clinically normal girl was born. It showed a right sided aortic arch. Surgical intervention was not necessary at the age of 4 months. Case 3: 33 year old. G2P1, 22 weeks of gestation, routine anomaly scan. U-sign was diagnosed in an otherwise normal fetus. Diagnosis of right-sided aortic arch with a ring around the trachea was made. Pregnanca is ongoing. Conclusion: Interposition of tissue between aorta and pulmonic artery is an easily recognizable pattern in routine anomaly scan and warrants further detailed work-up. It shows up as U-sign of aorta and pulmonic artery in utero. Karyotyping should be discussed and parents should be informed about the possible development of Arteria lusoria complications (stridor, feeding problems) in aortic arch abnormalities.

OC227b: Doppler detection of arterio‐arterial anastomosis predicts survival outcome independent of Quintero stage in TTTS

Objectives: 1) To assess the accuracy of fetal echocardiography in multiple pregnancy, and 2) To evaluate the type of congenital heart disease (CHD) and of extracardiac anomalies detected in 36 cases of multiple pregnancy. Method: We analysed a population of 248 pregnancies (546 fetuses, 39 with CHD). Diagnostic accuracy was calculated for fetal echocardiography. In fetuses with CHD, the following variables were analysed: chorionicity, gestational age at diagnosis, type of CHD, associated chromosomal and extracardiac abnormalities, fetoneonatal outcome. Results: In this series, sensitivity was 88.8%, specificity 99.8%, PPV 97.1% and NPV 99.1%. There were 4 FP and 1 FN cases. The association with aneuploidy was 9.3% (3/32). The spectrum of CHD was similar to that seen in singleton during the same period of time. Of note, that 8/32 (25.0%) fetuses with CHD were recipients from monochorionic pregnancies complicated by TTTS. As for the outcome, 21 (65.6%) neonates survived and 11 (34.4%) died prior to (9) or after surgery (2). Conclusions: Fetal echocardiography is clearly feasible also in multiple pregnancy without particular difficulties, at least for twins. In triplets and quadruplets, fetal crowding makes things a great deal more difficult. The association with aneuploidy is lower than expected, possibly due to the low incidence of extracardiac anomalies in this series and to the relatively small number of cases. As to the outcome, low birthweight coupled with CHD seem to be an important bad prognostic indicator, be it for growth restriction or simply prematurity.

P01.06: Significance of left superior caval vein in the fetus

Objective: To analyze the consequences of termination we studied the abortion rate, the distribution of CHD’s (inand excluding the abortions) and the year of termination, and compared the data to a contemporaneous postnatal population. Methods: We reviewed data from all isolated structural CHD’s either born or terminated between January 1 1991 and July 1 2003 at the Yale New Haven Hospital. We subdivided CHD diagnoses into those altering and not altering the four-chamber view. We developed a severity score to code for all CHD’s. Code 1 was given to a CHD amenable to non-complex biventricular repair, code 2 to complex biventricular repair, code 3 to non-complex univentricular repair and code 4 to complex univentricular repair. Results: Of the 236 prenatally diagnosed patients, 110 opted for an abortion (47%) and the remaining 126 decided to carry out their pregnancy (53%). Within the group of 206 CHD’s with abnormal four-chamber views termination of pregnancy was chosen significantly more often than in the group (n = 30) that did not have an altered four-chamber view. The abortion rate is the highest in group 3 (75%), going down to group 4 (51%), to group 2 (30%), to group 1 (7%), with a p-value 0.0001 in all steps. The distribution of severity scores comparing preand postnatally (n = 127) diagnoses showed a different pattern with the inor exclusion of abortions. The likelihood of abortion did not change in any severity score group over the 12.5 years this study covers. Conclusions: The spectrum of neonatal CHD’s is influenced by the option to terminate. Termination was chosen more often when the CHD alters the four-chamber view or when the CHD is not amenable to biventricular repair. The abortions changed the pattern of severity scores between the prenatal and postnatal diagnosis group. We have not seen a trend in the rate of termination within any of the severity score groups in the 12.5 year study period.

P349: Interstitial laser for vascular occlusion of fetal vasculature

the largest vertical amniotic fluid pocket of 14 cm. No obvious foetal anomalies were observed. Subsequent ultrasound evaluation at 22 weeks’ gestation revealed persistent polyhydramnios, a 51% discordance in the estimated foetal weights, and a significantly larger foetal bladder in the larger twin. TTTS was highly suspected, despite the absence of the polyhydramnios-oligohydramnios sequence. Foetal surgery with placental laser ablation of vascular anastomoses was planned, but at 23 weeks’ gestation, demise of both twins was noted. Pathological examination confirmed the diagnosis of TTTS. This case illustrates that in MM twin gestations, the diagnosis of TTTS can be made even in the absence of the polyhydramniosoligohydramnios sequence, as this finding cannot be appreciated without a dividing membrane. Twin-twin transfusion syndrome represents an additional hazard in MM twin pregnancies.

P343: Longer latency of AEDF in monochorionic twins

20–24 weeks anatomic scans), biochemical screening (first and/or second trimester), or amniocentesis. Results: Ten women were eligible for study. The mean gestational age at diagnosis was 37 weeks (range 35–40 weeks). The distribution of findings by systems was: central nervous system (CNS) (5), suspected systemic viral infection (1), gastrointestinal (GI) (2), renal (1), and cardiovascular (1). One woman with acute onset of massive hydrocephalus and increased ICP at 36 weeks gestation had an urgent cesarean section, and the neonate had a ventriculoperitoneal shunt. One woman with diffuse fetal cerebral cortical damage and an occipital cyst diagnosed at 40 weeks gestation terminated the pregnancy at another hospital. One neonate with a spinal cystic mass was operated on successfully. All infants are developing normally to date (range of follow-up 6 weeks to 18 months). Two pregnancies are still ongoing at 37 and 39 weeks gestation. Conclusions: This diverse group of patients manifests the importance of late third trimester diagnosis of fetal anomalies for the management and treatment of affected pregnancies. It is necessary to consider the benefit of performing another fetal anatomic scan by a specialist in the third trimester. Furthermore, the ethical implications of late third trimester pregnancy termination must be dealt with.