Neonatal outcome in twin-to-twin transfusion syndrome treated with fetoscopic laser occlusion of vascular anastomoses

Fetal anemia in monochorionic twins: a review on diagnosis, management, and outcome

INTRODUCTION

Monochorionic twins may develop fetal anemia when blood is unequally distributed via the placental vascular anastomoses. This review focuses on the causes of fetal anemia in complicated monochorionic twins and highlights the differences in management and outcome.

AREAS COVERED

Fetal anemia can occur in the context of twin anemia polycythemia sequence (TAPS), chronic twin-twin transfusion syndrome (TTTS) and acute peripartum TTTS, and in cotwins after single fetal demise. Diagnosis of fetal anemia is based on abnormal Doppler ultrasound measurements. Management options include fetoscopic laser surgery, intrauterine blood transfusion, or expectant management, depending on the type of complication and the severity of the disease. In all complications, fetal anemia may lead to perinatal mortality, neonatal morbidity, severe cerebral injury, and long-term neurodevelopmental impairment. In TAPS specifically, anemic donors may also show bilateral deafness.

EXPERT OPINION

Knowledge on the diagnosis and optimal treatment in TTTS is nowadays widespread, but caregivers often fail to distinguish TAPS from acute peripartum TTTS at birth. A full blood count including reticulocyte count is required, and placental dye injection is extremely helpful to reach the correct diagnosis and establish the optimal management.

Neonatal management and outcome in complicated monochorionic twins: What have we learned in the past decade and what should you know?

Monochorionic (MC) twin pregnancies are at increased risk of neonatal morbidity and mortality due to the shared placenta with vascular connections that can give rise to various complications, including twin-twin transfusion syndrome, twin anemia polycythemia sequence (TAPS), selective fetal growth restriction, and other hematological imbalances at birth. Each complication presents its own challenges and considerations in the neonatal period. Measurement of hemoglobin levels and reticulocyte count is required to establish a correct diagnosis. Placenta dye injection is needed to properly distinguish between the various conditions. Risk factors for adverse outcome in MC twins include prematurity, severe cerebral injury, and the type of MC pregnancy complication. We, therefore, recommend cerebral ultrasound examinations in all complicated MC twins at birth to rule out a severe brain injury. Lastly, we strongly encourage screening for hearing loss using automated auditory brainstem response in all spontaneous TAPS donors to prevent permanent speech development delay.

Behavioural outcome in twin-twin transfusion syndrome survivors treated with laser surgery

OBJECTIVE

Evaluate the incidence of and risk factors for behavioural problems in twin-twin transfusion syndrome (TTTS) survivors treated with fetoscopic laser coagulation.

DESIGN

Observational cohort study.

SETTING

National referral center for fetal therapy, Leiden University Medical Center, The Netherlands.

PATIENTS

Behavioural outcome was assessed in 417 TTTS survivors, at the age of 2 years.

INTERVENTIONS

Parents completed the Child Behavior Checklist for their twins. Antenatal, neonatal and follow-up data including Bayley III and a neurological exam were recorded from the medical database.

MAIN OUTCOME MEASURES

The incidence of and risk factors for behavioural problems.

RESULTS

332 twin pregnancies (664 fetuses) were treated with fetoscopic laser for TTTS between 2008 and 2015. For 517 children eligible for follow-up, 417 (81%) Child Behavior Checklist questionnaires were completed. The study group was born at a mean gestational age of 32.8 weeks±3.2. Total behavioural problems within the borderline to clinical range were reported in 8% (95% CI 5.9 to 11.2) of survivors, compared with 10% in the general Dutch population (p=0.12). No difference between donors and recipients was detected (p=0.84). Internalising and externalising problems were reported in 9.4% (95% CI 6.9 to 12.6) and 11.5% (95% CI 8.8 to 15.0), respectively. Severe neurodevelopmental impairment was more frequent in the children with behavioural problems. High maternal educational level was associated with lower behavioural problem scores.

CONCLUSION

Parents of twins treated with fetoscopic laser therapy for TTTS do not report more behavioural problems compared with general population norms. More behavioural problems are reported in children with severe neurodevelopmental impairment.

Neonatal Outcomes and Maternal Characteristics in Monochorionic Diamniotic Twin Pregnancies: Uncomplicated versus Twin-to-Twin Transfusion Syndrome Survivors after Fetoscopic Laser Surgery

Preterm birth remains a major complication of fetal laser surgery (FLS) due to twin-to-twin transfusion syndrome (TTTS).

OBJECTIVES

We tested the hypothesis that neonatal outcomes in fetuses born at >24 weeks are worse in TTTS survivors compared to uncomplicated monochorionic diamniotic (MCDA) twins.

METHODS

196 patients with TTTS treated with laser therapy and 91 uncomplicated MCDA gestations were compared. Neonatal outcomes included respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTN), bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, and neonatal death. Risk factors assessed were TTTS, maternal age, maternal body mass index, race, premature prolonged rupture of membranes, stage of TTTS, parity, and gestational age (GA) at delivery.

RESULTS

GA at delivery was lower in the TTTS group (31.0 ± 4.6 vs. 33.5 ± 2.4 weeks, p < 0.001). RDS and TTN occurred at higher rates in the TTTS than in the uncomplicated MCDA group. After multivariate logistic regression, the only factor significantly associated with the composite adverse outcome was GA at delivery (OR 0.61; 95% CI: 0.58-0.7).

CONCLUSION

TTTS twins treated with FLS are deliver 2.5 weeks earlier than uncomplicated MCDA twins. Respiratory complications were significantly higher in TTTS twins and were mainly the consequence of the early GA at delivery.

Outcome reporting across randomized trials and observational studies evaluating treatments for twin-twin transfusion syndrome: systematic review

OBJECTIVE

Twin-twin transfusion syndrome (TTTS) is associated with significant mortality and morbidity. Potential treatments for the condition require robust evaluation. The aim of this study was to evaluate outcome reporting across observational studies and randomized controlled trials assessing treatments for TTTS.

METHODS

Cochrane Central Register of Controlled Trials, EMBASE and MEDLINE were searched from inception to August 2016. Observational studies and randomized controlled trials reporting outcome following treatment for TTTS in monochorionic-diamniotic twin pregnancy and monochorionic-triamniotic or dichorionic-triamniotic triplet pregnancy were included. Outcome reporting was systematically extracted and categorized.

RESULTS

Six randomized trials and 94 observational studies were included, reporting data from 20 071 maternal participants and 3199 children. Six different treatments were evaluated. Included studies reported 62 different outcomes, including six fetal, seven offspring mortality, 25 neonatal, six early childhood and 18 maternal/operative outcomes. Outcomes were reported inconsistently across trials. For example, when considering offspring mortality, 31 (31%) studies reported live birth, 31 (31%) reported intrauterine death, 49 (49%) reported neonatal mortality and 17 (17%) reported perinatal mortality. Four (4%) studies reported respiratory distress syndrome. Only 19 (19%) studies were designed for long-term follow-up and 11 (11%) of these reported cerebral palsy.

CONCLUSIONS

Studies evaluating treatments for TTTS have often neglected to report clinically important outcomes, especially neonatal morbidity outcomes, and most are not designed for long-term follow-up. The development of a core outcome set could help standardize outcome collection and reporting in TTTS studies. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Outcome after fetoscopic laser coagulation in twin-twin transfusion syndrome - is the survival rate of at least one child at 6 months of age dependent on preoperative cervical length and preterm prelabour rupture of fetal membranes?

Purpose: Twin-to-twin transfusion syndrome (TTTS) complicates 10-15% of all monochorionic twin pregnancies. Selective laser coagulation of placental anastomoses is the only causal therapy. The aim of this study was to analyze the neonatal survival, the survival rate of at least one child at 6 months of age, and maternal outcome after laser therapy in a Swiss cohort.Material and methods: Between 2008 and 2014, 39 women were treated with fetoscopic laser procedure due to TTTS. Two women were excluded from the study because of missing informed consent or loss of follow-up. The women were divided into two groups: group 1 with a cervical length >25 mm and group 2 with a cervical length ≤25 mm. The primary end point was the survival rate of at least one child at 6 months of age and its dependence on maternal preoperative cervical length or the time interval between operation (OP)-preterm prelabour rupture of fetal membranes (PPROM). Secondary outcomes were neonatal complications and maternal complications due to the procedure. Statistical analysis was performed using the program SPSS 22. A p-value of <.05 was considered statistically significant.Results: Mean gestational age (GA) at OP of group 1 (20.3 ± 3 GW) was comparable with group 2 (21.5 ± 2.4 GW; p = .27). The GA at birth was significantly higher in group 1 (31.5 ± 5.9 GW) than in group 2 (27.0 ± 4.7 GW: p = .02). The survival rate of at least one child at 30 days and 6 months of age was 81% in group 1 and only 60% in group 2 (p = .1). PPROM <32 GW occurred in 43%. The survival rate of at least one child was significantly higher if the OP-PPROM interval was >28 days (93 versus 43%; p = .02). Major brain injury was observed in 11% of infants. Severe maternal complications (pulmonary edema) occurred in three cases (8%).Conclusions: Our survival rate of at least one child at 30 days and 6 months of age and the outcome of the mothers is well comparable to other international studies. A preoperative maternal cervical length of >25 mm and an occurrence of PPROM more than 28 days after the laser therapy is associated with a higher survival rate of at least one child at 6 months of age.

Hemoglobin Differences in Uncomplicated Monochorionic Twins in Relation to Birth Order and Mode of Delivery

Aim: To determine the differences in hemoglobin (Hb) levels in the first 2 days after birth in uncomplicated monochorionic twins in relation to birth order and mode of delivery. Methods: All consecutive uncomplicated monochorionic pregnancies with two live-born twins delivered at our center were included in this retrospective study. We recorded Hb levels at birth and on day 2, and analyzed Hb levels in association with birth order, mode of delivery, and time interval between delivery of twin 1 and 2. Results: A total of 290 monochorionic twin pairs were analyzed, including 171 (59%) twins delivered vaginally and 119 (41%) twins born by cesarean section (CS). In twins delivered vaginally, mean Hb levels at birth and on day 2 were significantly higher in second-born twins compared to first-born twins: 17.8 versus 16.1 g/dL and 18.0 versus 14.8 g/dL, respectively (p < .01). Polycythemia was detected more often in second-born twins (12%, 20/166) compared to first-born twins (1%, 2/166; p < .01). Hb differences within twin pairs delivered by CS were not statistically or clinically significant. We found no association between inter-twin delivery time intervals and Hb differences. Conclusions: Second-born twins after vaginal delivery have higher Hb levels and more often polycythemia than their co-twin, but not when born by CS.

Prediction of single fetal demise after laser therapy for twin-twin transfusion syndrome

OBJECTIVE

Single fetal demise (SFD) occurs in up to 20% of monochorionic pregnancies treated with laser coagulation for twin-twin transfusion syndrome (TTTS). We aimed to determine the independent factors associated with SFD to improve outcome in the care of TTTS pregnancies in the future.

METHODS

This was a case-control study on twin pregnancies treated for TTTS between 2007 and 2013. Data on ultrasound, laser surgery and outcome were retrieved from our monochorionic twin database. We analyzed separately cases of SFD in donor and recipient twins, and compared them with treated pregnancies that resulted in two live births.

RESULTS

Of the 273 TTTS pregnancies treated with laser coagulation, SFD occurred in 30 donors (11.0%) and 27 recipients (9.9%). In 67% of pregnancies with SFD, the death occurred within 1 week after laser treatment. For SFD in donors, absent/reversed end-diastolic flow in the umbilical artery was the strongest predictor (odds ratio (OR), 3.0 (95% CI, 1.1-8.0); P = 0.01), followed by the presence of an arterioarterial anastomosis (OR, 4.2 (95% CI, 1.4-13.1); P = 0.03) and discordance in estimated fetal weight (OR, 1.0 (95% CI, 1.0-1.1); P = 0.04). For SFD in recipients, independent predictors were absent/reversed A-wave in the ductus venosus (OR, 3.6 (95% CI, 1.2-10.5); P = 0.02) and the absence of recipient-to-donor arteriovenous anastomoses (OR, 10.6 (95% CI, 1.8-62.0); P < 0.01).

CONCLUSIONS

Our findings confirm earlier reports that suggest that abnormal blood flow is associated with SFD after laser treatment for TTTS. The association of SFD with the type of anastomoses is a new finding. We speculate that the type of anastomoses present determines the degree of hemodynamic change during laser therapy. Future strategies should aim at stabilizing fetal circulation before laser therapy to decrease the vulnerability to acute preload and afterload changes. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Neurodevelopmental outcome at 2 years in twin-twin transfusion syndrome survivors randomized for the Solomon trial

BACKGROUND

The preferred treatment for twin-twin transfusion syndrome is fetoscopic laser coagulation of inter-twin vascular anastomoses on the monochorionic placenta. Severe postoperative complications can occur when inter-twin vascular anastomoses remain patent including twin-anemia polycythemia sequence or recurrent twin-twin transfusion syndrome. To minimize the occurrence of residual anastomoses, a modified laser surgery technique, the Solomon technique, was developed in which the entire vascular equator is coagulated. In the Solomon randomized controlled trial (NTR1245), the Solomon technique was associated with a significant reduction in twin-anemia polycythemia sequence and recurrence of twin-twin transfusion syndrome when compared with the standard laser surgery technique. Although a significant improvement in perinatal outcome was shown after the Solomon technique, the clinical importance should also be ascertained with long-term follow-up evaluation of the surviving children.

OBJECTIVE

The purpose of this study was to compare the long-term neurodevelopmental outcome in surviving children with twin-twin transfusion syndrome who were included in the Solomon randomized trial and treated with either the Solomon technique or standard laser surgery technique.

STUDY DESIGN

Routine standardized follow-up evaluation in survivors, at least 2 years after the estimated date of delivery, was performed at 2 of the 5 centers that participated in the Solomon trial: Buzzi Hospital Milan (Italy) and Leiden University Medical Center (The Netherlands). The primary outcome of this follow-up study was survival without long-term neurodevelopmental impairment at age 2 years. Neurodevelopmental impairment was defined as cerebral palsy, cognitive and/or motor development score of <85, bilateral blindness, or deafness. Cognitive and motor development was evaluated with the use of Bayley-III. All analyses per fetus, neonate, or child were conducted with the generalized estimated equation module to account for the effect that observations between co-twins are not independent.

RESULTS

The primary outcome (survival without neurodevelopmental impairment) was detected in 95 of 141 cases (67%) in the Solomon group and in 99 of 146 cases (68%) in the standard group (P = .92). Neurodevelopmental impairment in long-term survivors who were included for follow-up evaluation was detected in 12 of 107 cases (11%) in the Solomon and in 10 of 109 cases (9%) in the standard group (P = .61). Neurodevelopmental impairment was due to cerebral palsy in 1 case (1%; spastic unilateral) in the Solomon group and in 2 cases (2%; spastic unilateral and spastic bilateral) in the standard group (P = .58). Cognitive development <85 cases was detected in 2 of 105 children (2%) in the Solomon group and in 6 of 106 children (6%) in the standard group (P = .23). Motor development <85 occurred in 8 of 103 children (8%) in the Solomon group and 3 of 104 children (3%) in the standard group (P = .23).

CONCLUSION

We found no difference in survival without neurodevelopmental impairment between the Solomon and standard laser techniques. In view of the reduction of short-term complications and the absence of increased adverse long-term effects, these data support the use of the Solomon technique in the treatment of twin-twin transfusion syndrome.

Short-Term Postnatal Renal Function in Twin Anemia-Polycythemia Sequence

OBJECTIVE

To evaluate the short-term renal function in neonates with twin anemia-polycythemia sequence (TAPS).

METHODS

All consecutive monochorionic twins with TAPS with double survivors admitted to three European centers were included in this retrospective study. Each twin pair was matched for gestational age at birth with a control twin pair unaffected by TAPS or twin-twin transfusion syndrome. Creatinine and urea levels in the first week after birth were recorded. Short-term postnatal renal dysfunction was defined as creatinine >100 μmol/l during the first week after birth.

RESULTS

A total of 52 TAPS twin pairs and 52 control twin pairs with a median gestational age of 31 weeks at birth were included in the study. In the TAPS group, donors had higher mean creatinine levels compared to recipients, 85 versus 71 μmol/l, respectively (p = 0.001). Short-term renal dysfunction was detected in 26.0% (13/50) of the donors versus 6.3% (3/48) of the recipients (p = 0.022). In the control group, no inter-twin differences in creatinine levels were found.

CONCLUSIONS

Donor twins with TAPS have higher creatinine levels than recipient twins, suggesting that chronic inter-twin transfusion in TAPS may also cause short-term renal dysfunction. Long-term renal consequences in TAPS donors require further investigation.

Twin-twin transfusion syndrome: neurodevelopmental screening test

OBJECTIVE

To assess the neurodevelopmental functions (cognition, language and motor function) of survivors of twin-twin transfusion syndrome (TTTS).

METHOD

Observational cross-sectional study of a total of 67 monochorionic diamniotic twins who underwent fetoscopic laser coagulation (FLC) for treatment of TTTS. The study was conducted at the Center for Investigation in Pediatrics (CIPED), Universidade Estadual de Campinas. Ages ranged from one month and four days to two years four months. Bayley Scales of Infant and Toddler Development Screening Test-III, were used for evaluation.

RESULTS

Most children reached the competent category and were classified as having appropriate performance. The preterm children scored worse than term infants for gross motor subtest (p = 0.036).

CONCLUSION

The majority of children reached the expected development according to their age. Despite the good neurodevelopment, children classified at risk should be monitored for development throughout childhood.

Single fetal demise in monochorionic pregnancies: incidence and patterns of cerebral injury

OBJECTIVE

To evaluate the incidence, type and severity of cerebral injury in the surviving monochorionic (MC) cotwin after single fetal demise in twin pregnancies.

METHODS

All MC pregnancies with single fetal demise that were evaluated at the Leiden University Medical Center between 2002 and 2013 were included. Perinatal characteristics, neonatal outcome and the presence of cerebral injury, observed on neuroimaging, were recorded for all cotwin survivors.

RESULTS

A total of 49 MC pregnancies with single fetal demise, including one MC triplet, were included in the study (n = 50 cotwins). Median gestational age at occurrence of single fetal demise was 25 weeks and median interval between single fetal demise and live birth was 61 days, with a median gestational age at birth of 36 weeks. Severe cerebral injury was diagnosed in 13 (26%) of the 50 cotwins and was detected antenatally in 4/50 (8%) and postnatally in 9/50 (18%) cases. Cerebral injury was mostly due to hypoxic-ischemic injury resulting in cystic periventricular leukomalacia, middle cerebral artery infarction or injury to basal ganglia, thalamus and/or cortex. Risk factors associated with severe cerebral injury were advanced gestational age at the occurrence of single fetal demise (odds ratio (OR), 1.14 (95% CI, 1.01-1.29) for each week of gestation; P = 0.03), twin-twin transfusion syndrome developing prior to single fetal demise (OR, 5.0 (95% CI, 1.30-19.13); P = 0.02) and a lower gestational age at birth (OR, 0.83 (95% CI, 0.69-0.99) for each week of gestation; P = 0.04).

CONCLUSIONS

Single fetal demise in MC pregnancies is associated with severe cerebral injury occurring in 1 in 4 surviving cotwins. Routine antenatal and postnatal neuroimaging, followed by standardized long-term follow-up, is mandatory.

Long term developmental outcomes of pre-school age children following laser surgery for twin-to-twin transfusion syndrome

BACKGROUND

Laser therapy is now a well recognised treatment for twin-to-twin transfusion syndrome (TTTS). We investigated the early childhood neurodevelopmental outcome of children post laser treatment for TTTS in our centre.

METHODS

Children of women who had laser therapy for TTTS between March 2006 and June 2008 were assessed at 30-69 months of age with WPPSI-III and a general health questionnaire. Major neurodevelopmental impairment (NDI) was reported as IQ<70 or cerebral palsy (CP). Borderline cognitive impairment was defined by IQ 70-79.

RESULTS

Amongst the 37 pregnancies treated, 62 infants were discharged home and the overall foetal survival rate was 84%. A total of 50 children (84%) from 31 pregnancies were assessed. Average age at assessment was 47 months. Two children with late treatment of congenital hypothyroidism were excluded. The majority of pregnancies were Quintero Stage III (74%). There was a significant trend for worse outcome with higher Quintero stage. The average gestational age at birth was 32 weeks. The majority (39, 78%) of children were found to be neurodevelopmentally normal; 9 (18%) had borderline cognitive development; and 2 (4%) had a major NDI, including one with cerebral palsy (2%).

CONCLUSIONS

There was a modest level of neurocognitive impairment post laser therapy for TTTS, mainly borderline cognitive development, lesser so major NDI. There was a low incidence of cerebral palsy. Routine developmental and neurological follow-up of these children is recommended.

Iatrogenic perforation of intertwin membrane after laser surgery for twin-to-twin transfusion syndrome

OBJECTIVE

To evaluate management and outcome of iatrogenic monoamniotic twins (iMAT) compared with twins with intact intertwin dividing membranes after laser surgery for twin-to-twin transfusion syndrome (TTTS).

METHODS

This was a retrospective analysis of twins with and without iatrogenic rupture of the intertwin membranes that had been treated for TTTS with laser surgery at our center between 2004 and 2012. Primary outcomes were perinatal survival and severe neonatal morbidity. Secondary outcomes were mode of delivery, gestational age at birth and cord entanglement.

RESULTS

In total, 338 pregnancies were included. In 67/338 (20%) pregnancies, iMAT was suspected antenatally. In 47 of these 67 (70%), a preterm Cesarean section was performed for monoamnionicity. Perinatal survival was 108/134 (81%) vs 396/542 (73%) in twins with intact intertwin membranes (P = 0.13). Mean gestational age at birth in iMAT was 31 completed weeks, compared to 33 weeks in twins with intact membranes (P < 0.01). At birth, cord entanglement was present in 8/67 (12%) iMAT pregnancies. Severe neonatal morbidity was assessed in 106/110 (96%) in iMAT cases and 392/416 (94%) in controls. The incidence of severe neonatal morbidity was 28/106 (26%) in iMAT vs 72/392 (18%) in controls (P = 0.25). Severe cerebral injury was significantly increased in the iMAT group as compared with controls, at 16/106 (15%) vs 18/392 (5%) (P < 0.01).

CONCLUSIONS

Iatrogenic rupture of intertwin membranes was suspected in 20% of pregnancies treated with laser therapy for TTTS and was associated with a lower gestational age at birth and increased neonatal morbidity.

Residual anastomoses in twin-twin transfusion syndrome after laser: the Solomon randomized trial

OBJECTIVE

Residual anastomoses after fetoscopic laser surgery for twin-to-twin transfusion syndrome (TTTS) may lead to severe postoperative complications, including recurrent TTTS and twin anemia-polycythemia sequence (TAPS). A novel technique (Solomon technique) using laser coagulation of the entire vascular equator was recently investigated in a randomized controlled trial (Solomon trial) and compared with the Standard selective laser technique. The aim of this secondary analysis was to evaluate the occurrence and characteristics of residual anastomoses in placentas included in the Solomon trial.

STUDY DESIGN

International multicenter randomized controlled trial in TTTS, randomized 1:1 ratio to either the Solomon laser technique or Standard laser technique. At time of laser, surgeons recorded whether they considered the procedure to be complete. Placental dye injection was performed after birth in the participating centers to evaluate the presence of residual anastomoses.

RESULTS

A total of 151 placentas were included in the study. The percentage of placentas with residual anastomoses in the Solomon group and Standard group was 19% (14/74) and 34% (26/77), respectively (P = .04). The percentage of placentas with residual anastomoses in the subgroup of cases where the procedure was recorded as complete was 8/65 (12%) and 22/69 (32%) in the Solomon group and Standard group, respectively (P < .01).

CONCLUSION

The Solomon laser technique reduces the risk of residual anastomoses. However, careful follow-up remains essential also after the Solomon technique, as complete dichorionization is not always achieved.

Laser surgery as a management option for twin anemia-polycythemia sequence

OBJECTIVE

To evaluate the effectiveness of laser treatment for antenatally detected twin anemia-polycythemia sequence (TAPS) compared with intrauterine transfusion or expectant management.

METHODS

All monochorionic twin pregnancies with TAPS managed between 2005 and 2013 in two European fetal therapy centers were evaluated. The outcomes of TAPS cases treated primarily with laser surgery were compared with the outcomes of cases managed expectantly or treated with intrauterine transfusion.

RESULTS

In this retrospective study 52 cases of TAPS were detected antenatally and were managed with either laser surgery (n=8; 15%) or intrauterine blood transfusion (n=17; 33%) or expectantly (n=27; 52%). Perinatal survival in the laser group was 94% (15/16) vs 85% (29/34) in the intrauterine-transfusion group and 83% (45/54) in the expectant-management group (P=0.30). The rates of severe neonatal morbidity in liveborn neonates in the laser, intrauterine-transfusion and expectant-management groups were 7% (1/15), 38% (12/32) and 24% (12/50), respectively (P=0.17). There was a significant reduction in respiratory distress syndrome in cases treated by laser. No severe postnatal hematological complications were detected in the laser group compared with 72% (23/32) in the intrauterine-transfusion group and 52% (26/50) in the expectant-management group (P<0.01). Median time between diagnosis and birth was 11 weeks in the laser group compared to 5 weeks after intrauterine transfusion and 8 weeks after expectant management (P<0.01). After injection of colored dye no residual anastomoses were found in the laser group.

CONCLUSIONS

Laser surgery for TAPS appears to improve perinatal outcome by prolonging pregnancy and reducing respiratory distress syndrome. Larger, adequately controlled studies are needed to reach firm conclusions on the optimal management of TAPS.

Fetoscopic laser coagulation of the vascular equator versus selective coagulation for twin-to-twin transfusion syndrome: an open-label randomised controlled trial

BACKGROUND

Monochorionic twin pregnancies complicated by twin-to-twin transfusion syndrome are typically treated with fetoscopic laser coagulation. Postoperative complications can occur due to residual vascular anastomoses on the placenta. We aimed to assess the efficacy and safety of a novel surgery technique that uses laser coagulation of the entire vascular equator (Solomon technique).

METHODS

We undertook an open-label, international, multicentre, randomised controlled trial at five European tertiary referral centres. Women with twin-to-twin transfusion syndrome were randomly assigned by online randomisation (1:1) with permuted blocks to the Solomon technique or standard laser coagulation. The primary outcome was a composite of incidence of twin anaemia polycythaemia sequence, recurrence of twin-to-twin transfusion syndrome, perinatal mortality, or severe neonatal morbidity. Analyses were by intention to treat, with results expressed as odds ratios (ORs) and 95% CIs. This trial is registered with the Dutch Trial Registry, number NTR1245.

FINDINGS

Between March 11, 2008, and July 12, 2012, 274 women were randomly assigned to either the Solomon group (n=139) or the standard treatment group (n=135). The primary outcome occurred in 94 (34%) of 274 fetuses in the Solomon group versus 133 (49%) of 270 in the standard treatment group (OR 0·54; 95% CI 0·35-0·82). The Solomon technique was associated with a reduction in twin anaemia polycythaemia sequence (3% vs 16% for the standard treatment; OR 0·16, 95% CI 0·05-0·49) and recurrence of twin-to-twin transfusion syndrome (1% vs 7%; 0·21, 0·04-0·98). Perinatal mortality and severe neonatal morbidity did not differ significantly between the two groups. Outside of the common and well-known complications of twin-to-twin transfusion syndrome and its treatment, no serious adverse events occurred.

INTERPRETATION

Fetoscopic laser coagulation of the entire vascular equator reduces postoperative fetal morbidity in severe twin-to-twin transfusion syndrome. We recommend that fetoscopic surgeons consider adopting this strategy for treatment of women with twin-to-twin transfusion syndrome.

FUNDING

Netherlands Organization for the Health Research and Development (ZonMw 92003545).

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.

Twin-to-twin transfusion syndrome and limb ischemia: a case report

Twin-to-twin transfusion syndrome (TTTS) is a severe complication of monochorionic twin pregnancies. This condition is associated with high mortality if untreated. Treatment consists of either serial reduction of amniotic fluid or selective laser photocoagulation (SLP). In utero limb ischemia is a known complication of TTTS. An interaction between this condition and SLP has never been established. Here, we describe the first of twins born at 34 weeks’ gestational age, delivered by emergency cesarean section for fetal distress after a pregnancy complicated by severe TTTS. The first twin, the recipient in the TTTS, showed a necrotic right limb, which was amputated above the knee joint on the 23rd day of life. Anatomic-pathological investigation revealed vascular thrombosis. The foot-length was compatible with a gestational age of 16–18 weeks, the time of limb ischemia, which is well before 26 weeks, when SLP was performed. Therefore, we refute that the fetal limb ischemia was a complication of SLP.

Intrauterine surgery--choices and limitations

BACKGROUND

The past decade has seen much progress in intrauterine surgery. Randomized trials have documented the benefit of some procedures of this type for the unborn child.

METHOD

Selective literature review

RESULTS

Randomized trials have demonstrated the benefit of fetoscopic laser coagulation of placental anastomoses in twin-to-twin transfusion syndrome (TTTS) and of intrauterine surgery via hysterotomy for the repair of spina bifida. Other fetoscopic procedures have yielded promising initial results but are not yet supported by findings from randomized trials. Some intrauterine surgical procedures must still be considered experimental in view of the lack of randomized trials and the rarity of the conditions they are designed to treat. Fetoscopic laser coagulation for TTTS is by far the most common procedure in fetal surgery; TTTS arises in roughly 1 in 2500 pregnancies. The other procedures discussed in this article are performed much less often and for rarer indications. In general, intrauterine surgery is indicated only to treat conditions that would otherwise lead to intrauterine death or irreversible prenatal damage.

CONCLUSION

Intrauterine surgery is a rapidly developing field. Prenatal intervention by laser coagulation is indicated to treat severe TTTS, as its benefit has been shown in a randomized trial. Not enough evidence is yet available for the possible benefit of intrauterine surgery to treat myelomeningocele and congenital diaphragmatic hernia. Other indications are experimental. When an indication for intrauterine surgery exists, the parents should be informed and, depending on their wishes, referred to a center where it can be performed.

Vascular limb occlusion in twin-twin transfusion syndrome (TTTS): case series and literature review

OBJECTIVE

The purpose of this study was to evaluate the phenomenon of vascular ischemic limb necrosis in twin-twin transfusion syndrome (TTTS).

STUDY DESIGN

This was a multicenter retrospective review of ischemic limb necrosis in patients with TTTS.

RESULTS

Twenty cases of fetal ischemic limb necrosis in association with TTTS were identified from 10 fetal medicine centers. The recipient was affected in 19 cases, and the lower limb was affected in 17 cases. The extent of the damage correlated with TTTS severity. Eighty percent of limb defects (16/20) clearly were unrelated to laser treatment (3 cases untreated, 7 cases after amnioreduction, 6 cases present at time of laser). The recipient was relatively polycythemic in 5 of 7 cases in which neonatal or fetal hemoglobin/hematocrit levels were available.

CONCLUSION

Ischemic limb necrosis is a rare complication of TTTS. The lesion is unrelated to therapy and may be the result of polycythemia, hypertension, and vasoconstriction.

Acute twin-twin transfusion syndrome in labor: pathophysiology and associated factors

OBJECTIVE

To review reported cases of acute twin-twin transfusion syndrome (TTTS) in monochorionic twin pregnancies to help define variants of disease and determine associated factors.

METHODS

PubMed literature review using the search terms, "acute" and "twin transfusion." Articles were reviewed for clinical factors. Reference lists were carefully assessed for any additional articles. In order to rule out sudden progression of chronic TTTS as the cause, gestational age ≥31 weeks was chosen. Cases were classified into subsets of acute TTTS.

RESULTS

There were 150 publications from 1942-2010. There were 51 cases that were classified into four variants of acute TTTS. Four cases were difficult to classify, with hemoglobin levels that were high normal and low normal, high normal and anemic, or low normal and polycythemic. Three publications defined the incidence for acute perinatal TTTS of 1.8-5.5% of monochorionic twins. Common factors associated with acute perinatal TTTS included monochorionicity and labor.

CONCLUSIONS

Monochorionicity and labor are common factors underlying the propensity to acute perinatal TTTS. A spectrum of severity is for acute TTTS was seen. Perinatal specialists and neonatologists should be aware of the possibility of acute TTTS during labor, so rapid volume replacement can be performed for neonatal resuscitation.

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.

Clinical outcome in neonates with twin anemia-polycythemia sequence

OBJECTIVE

The purpose of this study was to evaluate neonatal outcome of monochorionic twin pregnancies complicated by twin anemia-polycythemia sequence (TAPS).

STUDY DESIGN

A cohort of consecutive monochorionic twins with TAPS with double survivors was included in the study. Each twin pair with TAPS was compared with 2 monochorionic twin pairs who were unaffected by TAPS or twin-to-twin transfusion syndrome and who were matched for gestational age at birth. Neonatal death, severe morbidity, and cerebral injury were studied.

RESULTS

We included 19 twin pairs in the TAPS group and 38 control twin pairs. The incidence of neonatal death and severe neonatal morbidity was similar in the TAPS group and control group (3% [1/38] vs 1% [1/76] and 24% [9/38] vs 28% [21/76], respectively). Severe cerebral injury was detected in 1 infant (5%) in the TAPS group and 1 infant (2%) in the control group.

CONCLUSION

Neonatal mortality and morbidity rates in a select population of TAPS neonates are similar to control neonatal rates.

Twin-twin transfusion syndrome: an ethics-based and evidence-based argument for clinical research

Aspects of twin-twin transfusion syndrome (TTTS) diagnosis, treatment alternatives, and research opportunities were considered during a consensus conference that was held by the North American Fetal Therapy Network in 2009. A 3-member scientific consensus panel gathered data from expert conference presentations, postconference communications, and comprehensive scientific literature database searches to develop recommendations for TTTS diagnosis, therapy, and research. The panel recommends retaining the Quintero staging system until a superior system has been validated appropriately. It concludes that there is normative equipoise to justify the performance of randomized clinical trials to identify the optimal treatment strategy for mild TTTS. Recommendations for the design and conduct of clinical trials and observational studies are also provided.

Intestinal complications after antenatal fetoscopic laser ablation in twin-to-twin transfusion syndrome

Twin-to-twin transfusion syndrome (TTTS) occurs in 9% of monochorionic twin pregnancies. An imbalanced blood flow across placental vascular communications produces a hypovolemic condition in the donor fetus and hypervolemia in the recipient fetus, leading to a variety of postnatal complications. We report 3 cases of intestinal injury in TTTS after fetoscopic laser ablation of the communicating vessels: 2 cases of intestinal atresia, and 1 case of necrotizing enterocolitis of 1 twin. Intestinal ischemic diseases have been reported after prenatal laser treatment in TTTS; with this report, we add 3 more cases.

Incidence of complications in twin-twin transfusion syndrome after selective fetoscopic laser photocoagulation: a single-center experience

OBJECTIVE

The purpose of this study was to evaluate the incidence of complications after selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome (TTTS).

STUDY DESIGN

One hundred fifty-two cases of TTTS were treated with selective fetoscopic laser photocoagulation from 2005-2008. Complications were TTTS recurrence, amniotic band syndrome, iatrogenic monoamnionicity, and twin anemia-polycythemia sequence. Data were placed in the following categories: no complications; early complications < or =7 days; late complications >7 days; both early and late complications.

RESULTS

The incidence of early, late, and both early and late complications was 31%, 39%, and 10%. Complications included 2 cases (1.3%) of monoamnionicity, 3 cases (2.0%) of recurrent TTTS, 3 cases (2.0%) of twin anemia-polycythemia sequence, and 5 cases (3.3%) of amniotic band syndrome. Cases with TTTS with early complications had a lower number of superficial arteriovenous vascular anastomoses and 1 or both fetus survival (70.2% vs 96.7%; P < .001), compared with no complications. Fetal survival was 238 of 307 cases (77.5%), with 1 or both twins surviving in 134 of 152 (88%) of pregnancies.

CONCLUSION

The incidence of early, late, and both early and late complications was 31%, 39%, and 10%, respectively. Close postoperative surveillance is important.

Short- and long-term outcome in stage 1 twin-to-twin transfusion syndrome treated with laser surgery compared with conservative management

OBJECTIVE

We sought to compare short- and long-term outcome in Quintero stage 1 twin-to-twin transfusion syndrome (TTTS), managed with laser surgery or conservatively.

STUDY DESIGN

We conducted a retrospective study of all monochorionic twin pregnancies with stage 1 TTTS referred to our center. Primary outcomes were perinatal survival, neonatal morbidity, and long-term neurodevelopmental outcome.

RESULTS

Fifty women presented with stage 1 TTTS of which 40% (20/50) was treated with laser and 60% (30/50) was managed conservatively. Perinatal survival of both or at least 1 twin was 65% (13/20) and 85% (17/20) in the laser group, and 77% (23/30) and 97% (29/30) in the conservatively managed group (P = .52 and P = .29), respectively. Long-term neurodevelopmental impairment of the surviving infants was found in 0% (0/21) vs 23% (7/30), respectively (P = .03).

CONCLUSION

In this retrospective study, long-term outcome in stage 1 TTTS was better after laser surgery than with conservative management, suggesting the need for a randomized controlled trial.

Long-term neurodevelopmental outcome of monochorionic and matched dichorionic twins

BACKGROUND

Monochorionic (MC) twins are at increased risk for perinatal mortality and serious morbidity due to the presence of placental vascular anastomoses. Cerebral injury can be secondary to haemodynamic and hematological disorders during pregnancy (especially twin-to-twin transfusion syndrome (TTTS) or intrauterine co-twin death) or from postnatal injury associated with prematurity and low birth weight, common complications in twin pregnancies. We investigated neurodevelopmental outcome in MC and dichorionic (DC) twins at the age of two years.

METHODS

This was a prospective cohort study. Cerebral palsy (CP) was studied in 182 MC infants and 189 DC infants matched for weight and age at delivery, gender, ethnicity of the mother and study center. After losses to follow-up, 282 of the 366 infants without CP were available to be tested with the Griffiths Mental Developmental Scales at 22 months corrected age, all born between January 2005 and January 2006 in nine perinatal centers in The Netherlands. Due to phenotypic (un)alikeness in mono-or dizygosity, the principal investigator was not blinded to chorionic status; perinatal outcome, with exception of co-twin death, was not known to the examiner.

FINDINGS

Four out of 182 MC infants had CP (2.2%) - two of the four CP-cases were due to complications specific to MC twin pregnancies (TTTS and co-twin death) and the other two cases of CP were the result of cystic PVL after preterm birth - compared to one sibling of a DC twin (0.5%; OR 4.2, 95% CI 0.5-38.2) of unknown origin. Follow-up rate of neurodevelopmental outcome by Griffith's test was 76%. The majority of 2-year-old twins had normal developmental status. There were no significant differences between MC and DC twins. One MC infant (0.7%) had a developmental delay compared to 6 DC infants (4.2%; OR 0.2, 95% 0.0-1.4). Birth weight discordancy did not influence long-term outcome, though the smaller twin had slightly lower developmental scores than its larger co-twin.

CONCLUSIONS

There were no significant differences in occurrence of cerebral palsy as well as neurodevelopmental outcome between MC and DC twins. Outcome of MC twins seems favourable in the absence of TTTS or co-twin death.

Selective laser photocoagulation versus serial amniodrainage for the treatment of twin-twin transfusion syndrome: a cost-effectiveness analysis

OBJECTIVE

To compare the cost-effectiveness of selective laser photocoagulation (SLP) with serial amniodrainage (AD) in the treatment of twin-to-twin transfusion syndrome (TTTS).

STUDY DESIGN

Using decision-analysis modeling, we compared the cost-effectiveness of using laser photocoagulation with AD for the treatment of TTTS. The analysis was carried out from a societal perspective using a theoretical cohort of 1000 women with TTTS. Costs included the costs of procedures, perinatal complications from TTTS and of resources used for raising a child with cerebral palsy (CP) following TTTS. One-way, multiway and probabilistic (Monte Carlo) sensitivity analyses were carried out for all model variables. The main outcome measures were: cost per quality-adjusted life years (QALYs) gained from treating TTTS.

RESULT

On the basis of the available data, the decision model favors SLP as the most cost-effective treatment option compared with AD. Using the theoretical cohort, laser photocoagulation will result in an overall perinatal survival of 59.3% compared with 51.5% for AD. The frequency of children with CP after laser would be 8.5% compared with 15.4% after AD. Sensitivity analyses showed the model to be robust over a wide range of values for the variables, except when the overall survival associated with AD is >62%. Above that survival rate, AD was the more cost-effective therapy.

CONCLUSION

Under a wide range of circumstances, the most cost-effective therapy for TTTS is SLP.

Residual anastomoses in twin-to-twin transfusion syndrome treated with selective fetoscopic laser surgery: localization, size, and consequences

OBJECTIVE

To study the localization and size of residual anastomoses in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery and correlate the findings with outcome.

STUDY DESIGN

Placental injection in twin-to-twin transfusion syndrome placentas treated with laser was performed by using colored dye.

RESULTS

A total of 77 twin-to-twin transfusion syndrome placentas were included in the study. Residual anastomoses (n = 48) were found in 32% (25/77) of lasered placentas. Most residual anastomoses were localized near the margin of the placenta. The majority of residual anastomoses (67%; 32/48) were very small (diameter, < 1 mm). Eleven of the 25 cases (44%) in the residual anastomoses group developed twin anemia-polycythemia sequence.

CONCLUSION

Most residual anastomoses in twin-to-twin transfusion syndrome placentas treated with laser are very small and localized near the placental margin. Almost half of cases with residual anastomoses developed twin anemia-polycythemia sequence after laser surgery.

Twin-to-twin transfusion syndrome: a comprehensive update

Twin-to-twin transfusion syndrome (TTTS) is a serious complication in about 10% to 20% of monozygous twin gestations with an incidence of 4% to 35% in the United States. Severe TTTS is reported to occur in 5.5% to 17.5% of cases. TTTS is a progressive disease in which sudden deteriorations in clinical status can occur, leading to death of a co-twin. Up to 30% of survivors may have abnormal neurodevelopment as a result of the combination of profound antenatal insult and the complications of severe prematurity. This article presents an overview of what is known about the pathophysiology and the diagnosis of TTTS, the role of echocardiography in TTTS, treatment options available for TTTS, complications of treatment for TTTS, and short- and long-term outcomes of TTTS.

An embolic complication in a donor twin with severe twin-twin transfusion syndrome after fetoscopic intervention

Necrotic injury of an extremity in a donor twin is a rare complication of twin-twin transfusion syndrome after selective fetoscopic laser photocoagulation. We present the case of a 20-year-old gravida 2, para 1 with a twin gestation with severe twin-twin transfusion syndrome (Quintero Stage 3B) who had treatment with selective fetoscopic laser photocoagulation. Selective fetoscopic laser photocoagulation may be associated with extremity necrosis in a donor twin.

Fetal and neonatal haematological complications in monochorionic twins

Placental vascular anastomoses are almost invariably present in monochorionic (MC) placentas. These anastomoses are the essential anatomical substrate for the development of several haematological complications in MC twins, in particular twin-to-twin transfusion syndrome (TTTS). Several forms of TTTS have been described, including chronic TTTS, acute perimortem TTTS, twin anaemia-polycythaemia sequence, acute perinatal TTTS and twin reversed arterial perfusion sequence. A significant evolution in prenatal care strategies and management options for patients with TTTS has occurred during the last decade. In chronic TTTS, endoscopic laser ablation of communicating placental vessels has led to an increase in survival rates. This review analyzes the possible pathophysiologic mechanisms involved, discusses the latest findings in diagnosis, therapy and prognosis, and focuses on fetal and neonatal haematologic complications associated with the various forms of TTTS.

Congenital heart disease in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery

OBJECTIVE

To determine the incidence of congenital heart disease (CHD) and right ventricular outflow tract obstruction (RVOTO) in twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser surgery and evaluate the role of increased afterload by determining the difference in blood pressure and endothelin-1 at birth between donor and recipient twins.

DESIGN

Prospective study.

SETTING

Tertiary medical center, serving as the national referral center for fetoscopic laser surgery for TTTS in The Netherlands.

PATIENTS

All consecutive cases of monochorionic twins with TTTS treated with laser (n = 46 twin pairs) and monochorionic twins without TTTS (n = 55 twin pairs) delivered at our center between June 2002 and June 2005 were included in the study.

INTERVENTIONS

Echocardiography was performed within 1 week after delivery. At birth, blood pressure was measured in all survivors and endothelin-1 was determined in umbilical cord blood. Data on RVOTO in TTTS treated with laser surgery at our center but delivered elsewhere were reviewed retrospectively from medical records.

RESULTS

The incidence of CHD in the TTTS group and non-TTTS group was 5.4% (4/74) and 2.3% (2/87) (P = .42), respectively. RVOTO was diagnosed in 1 recipient twin delivered at our center and 2 recipient twins delivered elsewhere. The incidence of RVOTO in recipients was 4% (3/75). Mean systolic blood pressure at birth was similar in donor and recipient twins, respectively, 53 mm Hg vs. 56 mm Hg (P = .42). Mean endothelin-1 level at birth was also similar between donors and recipients, respectively, 14.3 ng/L and 13.2 ng/L (P = .64).

CONCLUSION

The incidence of CHD in TTTS treated with fetoscopic laser surgery is higher than in the general population (5.4% vs. 0.5%). We found no difference in afterload parameters between donors and recipients after laser treatment.

Laser therapy and serial amnioreduction as treatment for twin-twin transfusion syndrome: a metaanalysis and review of literature

OBJECTIVE

The objective of the study was to review current controversy on laser therapy (LT) vs serial amnioreduction (SA) performed for twin-twin transfusion syndrome (TTTS).

STUDY DESIGN

A search in PubMed from 1997-2007 was performed. Inclusion criteria were diamniotic monochorionic pregnancy, TTTS diagnosed with standard parameters, and peri- and neonatal outcomes well defined. Triplets and investigations on other topics of TTTS rather than perinatal outcomes were excluded. A metaanalysis was performed by fixed-effect model (heterogeneity <25%).

RESULTS

Ten articles provided 611 cases of TTTS (LT: 70%; SA: 30%) and included 4 studies comparing the 2 treatments (395 cases: LT, 58%; SA, 42%). Fetuses undergoing LT were more likely to survive than fetuses undergoing SA (overall survival rate: P < .0001; odds ratio [OR], 2.04; 95% confidence interval [CI], 1.52-2.76; neonatal death: P < .0001; OR, 0.24; 95% CI, 0.15-0.40; neurologic morbidity: P < .0001; OR, 0.20; 95% CI, 0.12-0.33).

CONCLUSION

This metaanalysis shows that LT is associated with better outcomes than SA and proposes new topics for future research.

The effect of fetoscopic laser therapy on fetal cardiac size in twin-twin transfusion syndrome

OBJECTIVES

To evaluate the influence of fetoscopic laser therapy on fetal cardiac size in monochorionic twins complicated by twin-twin transfusion syndrome (TTTS).

METHODS

In a longitudinal, prospective study, we assessed fetal cardiac size sonographically in monochorionic diamniotic twins with TTTS treated by laser therapy and in monochorionic twins without TTTS. The fetal cardiothoracic ratio (cardiac circumference divided by thoracic circumference) of TTTS twins was determined within 24 h before, 12-24 h after and 1 week after laser treatment, and from then on every 2-4 weeks until birth. TTTS twins were classified into Quintero Stages 1-2 (n = 18) and Stages 3-4 (n = 16), and measurements were compared with biweekly measurements of non-TTTS monochorionic twins matched for gestational age (n = 38). Cardiomegaly was defined as a cardiothoracic ratio above the 97.5th percentile.

RESULTS

Before laser treatment, cardiomegaly was observed in 44% (8/18) and 50% (8/16) of recipients in Quintero Stages 1-2 and Stages 3-4, respectively. Cardiomegaly occurred in none of the donors before treatment. After laser treatment, cardiomegaly was observed in 76% (13/17) and 50% (7/14) of recipients in Stages 1-2 and Stages 3-4, respectively, and in 17% (3/18) and 13% (2/15) of donors in Stages 1-2 and Stages 3-4, respectively. Cardiomegaly was present in 18% (7/38) and 8% (2/25) of non-TTTS monochorionic twins and singletons. After laser therapy, the cardiothoracic ratio of recipients in Stages 1-2 and Stages 3-4 was not significantly changed (P = 0.34 and P = 0.67, respectively). The cardiothoracic ratio of donors in Stages 1-2 and Stages 3-4 was increased compared with that before laser therapy (P = 0.0002 and P = 0.005, respectively). Cardiothoracic ratios of non-TTTS monochorionic twins were not significantly different from our reference range in singletons throughout gestation, and were smaller than those in both recipients and donors after laser therapy.

CONCLUSIONS

TTTS recipients show cardiomegaly before as well as after fetoscopic laser therapy for TTTS. Donors develop cardiomegaly only after laser treatment. Our findings emphasize the significant effect of TTTS and fetoscopic laser therapy on the fetal heart of both recipient and donor twins.

Increased perinatal mortality and morbidity in monochorionic versus dichorionic twin pregnancies: clinical implications of a large Dutch cohort study

OBJECTIVE

To evaluate mortality and morbidity in a large cohort of twin pregnancies according to chorionicity. We aimed to estimate the optimal time of delivery.

DESIGN

Historical cohort design. Setting Two teaching hospitals.

POPULATION

Twin pregnancies delivered in the University Medical Centre, Utrecht, and the St Elisabeth Hospital, Tilburg (1995-2004), The Netherlands (n = 1407).

METHODS

Pregnancy outcomes were documented according to chorionicity. Mortality >/=32 weeks was reviewed carefully with special attention to antenatal fetal monitoring, autopsy and placental histopathology to find an explanation for adverse outcome.

MAIN OUTCOME MEASURES

Perinatal mortality and morbidity in monochorionic (MC) and dichorionic (DC) twins.

RESULTS

Perinatal mortality was 11.6% in MC twin pregnancies and 5.0% in DC twin pregnancies. After 32 weeks, the risk of intrauterine death (IUD) was significantly higher in MC twins than in DC twins (hazard ratio 8.8, 95% CI 2.7-28.9). In most of these cases of IUD, no antenatal signs of impaired fetal condition had been present. Median gestational age was 1 week longer in DC twins than in MC twins, and the mean birthweight was 221 g higher. Severe birthweight discordancy (>20%) occurred more often in MC twins than in DC twins (OR 1.23, 95% CI 0.97-1.55). The incidence of necrotising enterocolitis (NEC) was higher in MC twins, after adjustment for age and weight at birth (OR 4.05, 95% CI 1.97-8.35). There was a trend towards higher neuromorbidity in MC twins.

CONCLUSIONS

This is the largest cohort study of twin pregnancies evaluating outcome according to chorionicity thus far. MC twins are at increased risk for fetal death (even at term), NEC and neuromorbidity. Current antenatal care is insufficient to predict and prevent this excess perinatal mortality and morbidity. Planned delivery at or even before 37 weeks of gestation seems to be justified for MC twins.

Twin-to-twin transfusion syndrome after 26 weeks of gestation: is there a role for fetoscopic laser surgery?

OBJECTIVE

To compare fetoscopic laser surgery with amniodrainage in the treatment of twin-to-twin transfusion syndrome (TTTS) diagnosed after 26 weeks of gestation.

DESIGN

A retrospective cohort study.

SETTING

Leiden University Medical Centre, a tertiary referral hospital for fetal therapy.

POPULATION

Between January 1991 and February 2006, 21 TTTS cases were diagnosed and treated after 26 weeks of gestation.

METHODS

Treatment of TTTS consisted of either amniodrainage or fetoscopic laser coagulation of vascular anastomoses.

MAIN OUTCOME MEASURES

PRIMARY OUTCOME

adverse outcome (intrauterine or neonatal death, major neonatal morbidity and/or severe cerebral injury). Secondary outcome: gestational age at birth.

RESULTS

Eleven TTTS cases were treated with amniodrainage and ten with laser surgery. Median gestational age at birth in the amniodrainage group and in the laser surgery group was 29 and 31 weeks, respectively (P = 0.17) All infants were born alive. Major neonatal morbidity occurred more often in the amniodrainage group than in the laser surgery group, 27% (6/22) and 0% (0/20), respectively (P = 0.02). Severe cerebral injury in the amniodrainage group and in the laser surgery group occurred in 23% (5/22) and 15% (3/20) of infants, respectively (P = 0.70). Neonatal mortality in the amniodrainage group and in the laser surgery group was 14% (3/22) and 0% (0/20), respectively (P = 0.23). Overall adverse outcome was 36% (8/22) in the amniodrainage group and 15% (3/20) in the laser surgery group (P = 0.17).

CONCLUSION

In TTTS diagnosed after 26 weeks of gestation, amniodrainage and laser surgery both result in 100% survival. However, infants born after laser surgery have less major neonatal morbidity.

Neonatal outcome in preterm monochorionic twins with twin-to-twin transfusion syndrome after intrauterine treatment with amnioreduction or fetoscopic laser surgery: comparison with dichorionic twins

OBJECTIVE

The purpose of this study was to compare neonatal outcome in preterm neonates after twin-to-twin transfusion syndrome (TTTS) that was treated by amnioreduction or fetoscopic laser surgery (FLS) and in dichorionic neonates who were matched for gestational age at birth.

STUDY DESIGN

Neonatal outcome was assessed in 137 TTTS preterm neonates who were treated primarily with either amnioreduction (n = 36) or FLS (n = 101) and compared with dichorionic twins (n = 242) who were delivered at our center at 24-34 weeks of gestation.

RESULTS

Adverse neonatal outcome (death or severe cerebral lesions) was more frequent in the amnioreduction group than in the FLS and dichorionic groups. Overall neonatal outcome was comparable in FLS and dichorionic infants. However, neonatal morbidity was higher in FLS neonates at <30 weeks of gestation that was related mainly to failed laser therapy.

CONCLUSION

In preterm TTTS cases, neonatal morbidity decreases independently with gestational age and after successful FLS. Neonatal morbidity that was specific of TTTS was higher in the amnioreduction group and in cases with failed laser therapy.

Residual Anastomoses After Fetoscopic Laser Surgery in Twin-to-Twin Transfusion Syndrome: Frequency, Associated Risks and Outcome

Fetoscopic laser coagulation of placental vascular anastomoses is considered to be the treatment of choice in severe twin-to-twin transfusion syndrome. The aim of fetoscopic laser surgery is to separate completely the inter-twin placental circulation. Incomplete laser coagulation may result in residual vascular anastomoses. The incidence and clinical implications of residual anastomoses in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery has not yet been studied. We examined all placentas treated with fetoscopic laser surgery and delivered at our center between June 2002 and December 2005 with vascular injection using colored dyes. Presence of residual anastomoses was studied in association with adverse outcome and inter-twin hemoglobin difference at birth. Adverse outcome was defined as fetal demise, neonatal death or severe cerebral injury. The relation between residual anastomoses and placental localization (anterior or posterior uterine wall) was evaluated. A total of 52 laser-treated placentas were studied. Residual anastomoses were detected in 33% (17/52) of placentas. Adverse outcome was similar in the groups with and without residual anastomoses, 18% (6/34) and 29% (20/70), respectively (p=0.23). Large inter-twin hemoglobin differences (>5g/dL) were found in 65% (11/17) of cases with residual anastomoses and 20% (7/35) of cases without residual anastomoses (p<0.01). Anterior placental localization was not associated with a more frequent presence of residual anastomoses. In conclusion, residual anastomoses at our institution are seen in one-third of monochorionic placentas treated with fetoscopic laser surgery. Although residual anastomoses in our study were not associated with adverse outcome, they were often associated with neonatal hematological complications.

Velamentous cord insertion and unequal placental territories in monochorionic twins with and without twin-to-twin-transfusion syndrome

OBJECTIVE

The objective of this study was to determine the incidence of velamentous cord insertion and placental territory discordancy in monochorionic twins with and without twin-to-twin transfusion syndrome (TTTS).

STUDY DESIGN

All consecutive placentas of monochorionic twins delivered at our center between June 2002 and April 2006 were studied with vascular injection of the umbilical vessels with colored dyes. Velamentous cord insertions were recorded and individual placental territories were calculated by computer analysis.

RESULTS

A total of 76 monochorionic placentas with TTTS and 63 monochorionic placentas without TTTS were studied. The incidence of velamentous cord insertion (per fetus) in the TTTS group and the non-TTTS group was 13% (20 of 152) and 14% (18 of 126), respectively (P = .79). Placental territory discordancy in the TTTS group and the non-TTTS group was 20% and 20% (P = 0.83). In the TTTS group, donor twins had a velamentous cord insertion more often than recipient twins (24% and 3%, respectively, P < .001) and a smaller placental territory (44% and 56%, respectively, P < .001).

CONCLUSION

Our findings suggest that velamentous cord insertion and unequal placental territory are not critical factors for the development of TTTS.

Fetoscopic laser surgery in 100 pregnancies with severe twin-to-twin transfusion syndrome in the Netherlands

OBJECTIVE

In this prospective cohort study, we evaluated the initial results of fetoscopic laser surgery for severe second trimester twin-to-twin transfusion syndrome (TTTS) treated at our centre.

METHOD

A total of 100 consecutive pregnancies with severe second trimester TTTS treated at our centre with selective fetoscopic laser coagulation of vascular anastomoses on the placental surface between August 2000 and November 2004 were included in the study. Perinatal survival was analysed in relation to Quintero stage.

RESULTS

Median gestational age was 20 weeks at fetoscopy (range: 16-26) and 33 weeks at delivery (range: 18-40). Perinatal survival rate was 70% (139/200). The treatment resulted in at least one survivor at the age of 4 weeks in 81% of pregnancies. Perinatal survival was significantly higher when treatment was performed in the early Quintero stages (95% in stage 1, 76% in stage 2, 70% in stage 3, 50% in stage 4) (p = 0.02).

CONCLUSION

Results of fetoscopic laser surgery for TTTS in our centre are similar to those in specialised centres in other countries. Diagnosis and treatment in the early Quintero stages resulted in significantly higher perinatal survival.

Incidence, origin, and character of cerebral injury in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery

OBJECTIVE

The objective of the study was to determine the incidence, origin, and character of cerebral lesions in monochorionic twins with twin-to-twin transfusion syndrome treated with fetoscopic laser surgery.

STUDY DESIGN

This was a prospective study of monochorionic twins with twin-to-twin transfusion syndrome treated with fetoscopic laser surgery and monochorionic twins without twin-to-twin transfusion syndrome delivered at our center between June 2002 and September 2005, using cranial ultrasonography.

RESULTS

Incidence of antenatally acquired severe cerebral lesions in the twin-to-twin transfusion syndrome group was 10% (8/84) and 2% (2/108) in the non-twin-to-twin transfusion syndrome group (P = .02). Incidence of severe cerebral lesions at discharge was 14% (12/84) in the twin-to-twin transfusion syndrome group and 6% (6/108) in the non-twin-to-twin transfusion syndrome group (P = .04). Antenatal injury was responsible for severe cerebral lesions in 67% (8/12) of the twin-to-twin transfusion syndrome group.

CONCLUSION

Incidence of severe cerebral lesions in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery is high and results mainly from antenatal injury.