Stage I twin-twin transfusion syndrome: rates of progression and regression in relation to outcome

Society for Maternal-Fetal Medicine Consult Series #72: Twin-twin transfusion syndrome and twin anemia-polycythemia sequence

Thirty percent of spontaneously occurring twins are monozygotic, of which two-thirds are monochorionic, possessing a single placenta. A common placental mass with shared intertwin placental circulation is key to the development and management of complications unique to monochorionic gestations. In this Consult, we review general considerations and a contemporary approach to twin-twin transfusion syndrome and twin anemia-polycythemia sequence, providing management recommendations based on the available evidence. The following are the Society for Maternal-Fetal Medicine recommendations: (1) we recommend routine first-trimester sonographic determination of chorionicity and amnionicity (GRADE 1B); (2) we recommend that ultrasound surveillance for twin-twin transfusion syndrome begin at 16 weeks of gestation for all monochorionic-diamniotic twin pregnancies and continue at least every 2 weeks until delivery, with more frequent monitoring indicated with clinical concern (GRADE 1C); (3) we recommend that routine sonographic surveillance for twin-twin transfusion syndrome minimally include assessment of amniotic fluid volumes on both sides of the intertwin membrane and evaluation for the presence or absence of urine-filled fetal bladders, and ideally incorporate Doppler study of the umbilical arteries (GRADE 1C); (4) we recommend fetoscopic laser surgery as the standard treatment for stage II through stage IV twin-twin transfusion syndrome presenting between 16 and 26 weeks of gestation (GRADE 1A); (5) we recommend expectant management with at least weekly fetal surveillance for asymptomatic patients continuing pregnancies complicated by stage I twin-twin transfusion syndrome, and consideration for fetoscopic laser surgery for stage I twin-twin transfusion syndrome presentations between 16 and 26 weeks of gestation complicated by additional factors such as maternal polyhydramnios-associated symptomatology (GRADE 1B); (6) we recommend an individualized approach to laser surgery for early- and late-presenting twin-twin transfusion syndrome (GRADE 1C); (7) we recommend that all patients with twin-twin transfusion syndrome qualifying for laser therapy be referred to a fetal intervention center for further evaluation, consultation, and care (Best Practice); (8) after laser therapy, we suggest weekly surveillance for 6 weeks followed by resumption of every-other-week surveillance thereafter, unless concern exists for post-laser twin-twin transfusion syndrome, post-laser twin anemia-polycythemia sequence, or fetal growth restriction (GRADE 2C); (9) following the resolution of twin-twin transfusion syndrome after fetoscopic laser surgery, and without other indications for earlier delivery, we recommend delivery of dual-surviving monochorionic-diamniotic twins at 34 to 36 weeks of gestation (GRADE 1C); (10) in twin-twin transfusion syndrome pregnancies complicated by posttreatment single fetal demise, we recommend full-term delivery (39 weeks) of the surviving co-twin to avoid complications of prematurity unless indications for earlier delivery exist (GRADE 1C); (11) we recommend that fetoscopic laser surgery not influence the mode of delivery (Best Practice); (12) we recommend that prenatal diagnosis of twin anemia-polycythemia sequence minimally require either middle cerebral artery Doppler peak systolic velocity values >1.5 and <1.0 multiples of the median in donor and recipient twins, respectively, or an intertwin Δ middle cerebral artery peak systolic velocity >0.5 multiples of the median (GRADE 1C); (13) we recommend that providers consider incorporating middle cerebral artery Doppler peak systolic velocity determinations into all monochorionic twin ultrasound surveillance beginning at 16 weeks of gestation (GRADE 1C); and (14) consultation with a specialized fetal care center is recommended when twin anemia-polycythemia sequence progresses to a more advanced disease stage (stage ≥II) before 32 weeks of gestation or when concern arises for coexisting complications such as twin-twin transfusion syndrome (Best Practice).

Minimally Invasive Fetal Surgery and the Next Frontier

Most patients with congenital anomalies do not require prenatal intervention. Furthermore, many congenital anomalies requiring surgical intervention are treated adequately after birth. However, there is a subset of patients with congenital anomalies who will die before birth, shortly after birth, or experience severe postnatal complications without fetal surgery. Fetal surgery is unique in that an operation is performed on the fetus as well as the pregnant woman who does not receive any direct benefit from the surgery but rather lends herself to risks, such as hemorrhage, abruption, and preterm labor. The maternal risks involved with fetal surgery have limited the extent to which fetal interventions may be performed but have, in turn, led to technical innovations that have significantly advanced the field. This review will examine congenital abnormalities that can be treated with minimally invasive fetal surgery and introduce the next frontier of prenatal management of fetal surgical pathology.

Outcomes of laser surgery for stage I twin-twin transfusion syndrome

OBJECTIVE

A recent randomized controlled trial (RCT) demonstrated no difference in 6 month survival in expectantly managed stage I twin-twin transfusion syndrome (TTTS) patients and those undergoing immediate laser surgery. We aimed to describe outcomes following immediate laser surgery at a single fetal surgery center.

METHODS

A retrospective study of monochorionic diamniotic twins diagnosed with stage I TTTS who underwent laser surgery between 16 and 26 gestational weeks from 2006 to 2019. The primary outcome was 6 month survivorship. Intact survival was also assessed. Secondarily, outcomes were compared to the RCT expectant management group.

RESULTS

Of 126 consecutive stage I TTTS patients, 114 (90.5%) met inclusion criteria. Median (range) gestational age at delivery was 34.1 (20.6-39.4) weeks. At 6 months, the proportion of patients with at-least-one survivor in the single-center-laser cohort was 97.4%, with 88.6% dual survivorship. Neurological morbidity outcomes were available in 110 pregnancies (220 fetuses). Severe neurological morbidity occurred in 2.7% (6/220), and 6 month survival without severe neurological morbidity was 90.0%. Outcomes compared favorably with the RCT expectant management group.

CONCLUSIONS

Given favorable survival and neurological outcomes, laser surgery is a reasonable treatment option for stage I TTTS at experienced fetal surgery centers. Further study is warranted to optimize treatment strategies.

Intrauterine fetoscopic laser surgery versus expectant management in stage 1 twin-to-twin transfusion syndrome: an international randomized trial

BACKGROUND

Selective fetoscopic laser coagulation of the intertwin anastomotic chorionic vessels is the first-line treatment for twin-twin transfusion syndrome. However, in stage 1 twin-twin transfusion syndrome, the risks of intrauterine surgery may be higher than those of the natural progression of the condition.

OBJECTIVE

This study aimed to compare immediate surgery and expectant follow-up in stage 1 twin-twin transfusion syndrome.

STUDY DESIGN

We conducted a multicentric randomized trial, which recruited from 2011 to 2018 with a 6-month postnatal follow-up. The study was conducted in 9 fetal medicine centers in Europe and the Unites States. Asymptomatic women with stage 1 twin-twin transfusion syndrome between 16 and 26 weeks' gestation, a cervix of >15 mm, and access to a surgical center within 48 hours of diagnosis were randomized between expectant management and immediate surgery. In patients allocated to immediate laser treatment, percutaneous laser coagulation of anastomotic vessels was performed within 72 hours. In patients allocated to expectant management, a weekly ultrasound follow-up was planned. Rescue fetoscopic coagulation of anastomoses was offered if the syndrome worsened as seen during a follow-up, either because of progression to a higher Quintero stage or because of the maternal complications of polyhydramnios. The primary outcome was survival at 6 months without severe neurologic morbidity. Severe complications of prematurity and maternal morbidity were secondary outcomes.

RESULTS

The trial was stopped at 117 of 200 planned inclusions for slow accrual rate over 7 years: 58 women were allocated to expectant management and 59 to immediate laser treatment. Intact survival was seen in 84 of 109 (77%) expectant cases and in 89 of 114 (78%) (P=.88) immediate surgery cases, and severe neurologic morbidity occurred in 5 of 109 (4.6%) and 3 of 114 (2.6%) (P=.49) cases in the expectant and immediate surgery groups, respectively. In patients followed expectantly, 24 of 58 (41%) cases remained stable with dual intact survival in 36 of 44 (86%) cases at 6 months. Intact survival was lower following surgery than for the nonprogressive cases, although nonsignificantly (78% and 71% following immediate and rescue surgery, respectively).

CONCLUSION

It is unlikely that early fetal surgery is of benefit for stage 1 twin-twin transfusion syndrome in asymptomatic pregnant women with a long cervix. Although expectant management is reasonable for these cases, 60% of the cases will progress and require rapid transfer to a surgical center.

Twin to twin transfusion syndrome

Twin to twin transfusion syndrome (TTTS) is a common complication that typically presents in the second trimester of pregnancy in 10-15% of monochorionic twins due to net transfer of volume and hormonal substances from one twin to the other across vascular anastomoses on the placenta. Without recognition and treatment, TTTS is the greatest contributor to fetal loss prior to viability in 90-100% of advanced cases. Ultrasound diagnosis of monochorionicity is most reliable in the first trimester and sets the monitoring strategy for this type of twins. The diagnosis of TTTS is made by ultrasound with the findings of polyhydramnios due to volume overload and polyuria in one twin and oligohydramnios due to oliguria of the co-twin. Assessment of bladder filling as well as arterial and venous Doppler patterns are required for staging disease severity. Assessment of fetal cardiac function also provides additional insight into the fetal cardiovascular impacts of the disease as well as help identify fetuses that may require postnatal follow up. Fetoscopic laser ablation of the communicating vascular anastomoses between the twins is the standard treatment for TTTS. It aims to cure the condition by interrupting the link between their circulations and making them independent of one another. Contemporary outcome data after laser surgery suggests survival for both fetuses can be anticipated in up to 65% of cases and survival of a single fetus in up to 88% of cases. However, preterm birth remains a significant contributor to postnatal morbidity and mortality. Long term outcomes of TTTS survivors indicate that up to 11% of children may show signs of neurologic impairment. Strategies to minimize preterm birth after treatment and standardized reporting by laser centers are important considerations to improve overall outcomes and understand the long-term impacts of TTTS.

Outcome of twin-twin transfusion syndrome according to Quintero stage of disease: systematic review and meta-analysis

OBJECTIVES

To report the outcome of pregnancies complicated by twin-twin transfusion syndrome (TTTS) according to Quintero stage.

METHODS

MEDLINE, EMBASE and CINAHL databases were searched for studies reporting the outcome of pregnancies complicated by TTTS stratified according to Quintero stage (I-V). The primary outcome was fetal survival rate according to Quintero stage. Secondary outcomes were gestational age at birth, preterm birth (PTB) before 34, 32 and 28 weeks' gestation and neonatal morbidity. Outcomes are reported according to the different management options (expectant management, laser therapy or amnioreduction) for pregnancies with Stage-I TTTS. Only cases treated with laser therapy were considered for those with Stages-II-IV TTTS and only cases managed expectantly were considered for those with Stage-V TTTS. Random-effects head-to-head meta-analysis was used to analyze the extracted data.

RESULTS

Twenty-six studies (2699 twin pregnancies) were included. Overall, 610 (22.6%) pregnancies were diagnosed with Quintero stage-I TTTS, 692 (25.6%) were Stage II, 1146 (42.5%) were Stage III, 247 (9.2%) were Stage IV and four (0.1%) were Stage V. Survival of at least one twin occurred in 86.9% (95% CI, 84.0-89.7%) (456/552) of pregnancies with Stage-I, in 85% (95% CI, 79.1-90.1%) (514/590) of those with Stage-II, in 81.5% (95% CI, 76.6-86.0%) (875/1040) of those with Stage-III, in 82.8% (95% CI, 73.6-90.4%) (172/205) of those with Stage-IV and in 54.6% (95% CI, 24.8-82.6%) (5/9) of those with Stage-V TTTS. The rate of a pregnancy with no survivor was 11.8% (95% CI, 8.4-15.8%) (69/564) in those with Stage-I, 15.0% (95% CI, 9.9-20.9%) (76/590) in those with Stage-II, 18.6% (95% CI, 14.2-23.4%) (165/1040) in those with Stage-III, 17.2% (95% CI, 9.6-26.4%) (33/205) in those with Stage-IV and in 45.4% (95% CI, 17.4-75.2%) (4/9) in those with Stage-V TTTS. Gestational age at birth was similar in pregnancies with Stages-I-III TTTS, and gradually decreased in those with Stages-IV and -V TTTS. Overall, the incidence of PTB and neonatal morbidity increased as the severity of TTTS increased, but data on these two outcomes were limited by the small sample size of the included studies. When stratifying the analysis of pregnancies with Stage-I TTTS according to the type of intervention, the rate of fetal survival of at least one twin was 84.9% (95% CI, 70.4-95.1%) (94/112) in cases managed expectantly, 86.7% (95% CI, 82.6-90.4%) (249/285) in those undergoing laser therapy and 92.2% (95% CI, 84.2-97.6%) (56/60) in those after amnioreduction, while the rate of double survival was 67.9% (95% CI, 57.0-77.9%) (73/108), 69.7% (95% CI, 61.6-77.1%) (203/285) and 80.8% (95% CI, 62.0-94.2%) (49/60), respectively.

CONCLUSIONS

Overall survival in monochorionic diamniotic pregnancies affected by TTTS is higher for earlier Quintero stages (I and II), but fetal survival rates are moderately high even in those with Stage-III or -IV TTTS when treated with laser therapy. Gestational age at birth was similar in pregnancies with Stages-I-III TTTS, and gradually decreased in those with Stages-IV and -V TTTS treated with laser and expectant management, respectively. In pregnancies affected by Stage-I TTTS, amnioreduction was associated with slightly higher survival compared with laser therapy and expectant management, although these findings may be confirmed only by future head-to-head randomized trials. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Outcomes following selective fetoscopic laser ablation for twin-to-twin transfusion syndrome: a single-centre experience

INTRODUCTION

Fetoscopic laser photocoagulation (FLP), a treatment option for twin-to-twin transfusion syndrome (TTTS) in monochorionic twin pregnancies, is currently the treatment of choice at our centre. We previously reported on our experience of FLP from June 2011 to March 2014. This paper audits our fetal surgery performance since then.

METHODS

15 consecutive patients who underwent FLP for Stage II-III TTTS before 26 weeks of gestation from June 2011 to January 2017 were retrospectively reviewed, consisting of five cases from our initial experience and ten subsequent cases. Perioperative, perinatal and neonatal outcomes were analysed.

RESULTS

Of 15 pregnancies, 10 (66.7%) and 5 (33.3%) were for Stage II and III TTTS respectively, with FLP performed at an earlier Quintero stage in the later cohort. Overall mean gestational ages at presentation, laser and delivery were comparable between the cohorts at 19.7 (15.4-24.3) weeks, 20.3 (16.3-25.0) weeks and 31.2 (27.6-37.0) weeks, respectively. 2 (13.3%) cases had intra-amniotic bleeding and 1 (6.7%) had iatrogenic septostomy. 1 (6.7%) case had persistent TTTS requiring repeat FLP, and another (6.7%) had preterm premature rupture of membranes at seven weeks post procedure. The overall perinatal survival rate was 21 (75.0%) out of 28 infants. One mother underwent termination of pregnancy for social reasons at 1.4 weeks post procedure. Double survival occurred in 8 (57.1%) out of 14 pregnancies, while 13 (92.9%) had at least one survivor.

CONCLUSION

FLP requires a highly specialised team and tertiary neonatal facility. Continual training improves maternal and perinatal outcomes, ensuring comparable standards with international centres.

Update on twin-to-twin transfusion syndrome

Twin-to-twin transfusion syndrome (TTTS) is a serious complication that affects 10-15% of monochorionic multiple pregnancies. Communicating placental vessels on the chorionic plate between the donor and recipient twin are responsible for the imbalance of blood flow. There is evidence for the superiority of fetoscopic laser ablation over serial amnioreductions regarding survival and neurological outcome for stages II-IV TTTS. However, the optimal management of stage I is still debated. The "Solomon" technique showed a significant reduction in recurrent TTTS and post laser twin anemia-polycythemia sequence (TAPS) in comparison to the selective laser method without improvement in perinatal mortality or neonatal morbidity. Survival rates after fetoscopic laser surgery have significantly increased over the last 25 years. High volume centers report up to 70% double survival and at least one survivor in >90%. Long-term neurodevelopmental impairment occurs in about 10% of children after laser surgery. In this review we discuss the optimal management, innovations in laser technique, long-term neurodevelopmental outcome, and future aspects of TTTS treatment.

Twin-twin transfusion syndrome - What we have learned from clinical trials

Monochorionic twin pregnancies are at increased risk for adverse outcome compared to dichorionic twin pregnancies and singletons. Monochorionic-specific complications include twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence, single intrauterine fetal demise and its consequences on the co-twin, and selective intrauterine growth restriction. Whereas the natural history of monochorionic-specific complications carries a high risk of fetal death or severe neurologic disability, a framework now exists, based on well-designed clinical trials, for optimal treatment of these entities. Fetoscopic selective laser coagulation of anastomotic vessels on the chorionic plate has been clearly demonstrated to improve survival and neurologic outcomes for Quintero stage ≥2 TTTS. However, many challenges remain unsolved, the most important of which is preterm premature rupture of membranes. Further improvement in the outcomes of monochorionic pregnancies will require improvements in the rate of premature delivery, and improved diagnosis and treatment strategies for early and late onset TTTS.

[Fetoscopic laser coagulation in 200 consecutive monochorionic pregnancies with twin-twin transfusion syndrome]

OBJECTIVES

To report preoperative data, surgical characteristics, complications and perinatal outcome of twin-twin transfusion syndrome (TTTS) managed with laser ablation surgery, to analyze predictors of neonatal survival and to compare the 100 most recent cases with the older 100.

MATERIALS AND METHODS

Observational cohort moncentric study of 200 cases of TTTS consecutively treated with fetoscopic laser coagulation between January 2004 and December 2014.

RESULTS

There were 49 stage I, 88 stage II, 55 stage III and eight stage IV. Median gestation at time of laser was 20.1±3.0 weeks' gestation (WG) whereas median gestation at delivery was 31.6±5.4 WG. Overall perinatal survival rate was 68.0% and 84.0% have one or more surviving twins. Preterm premature rupture of membranes occurred in 39 cases with and the median gestational age for this complication was 28.8±4.6 SA. Predictive factors to have at least one living birth were Quintero stage and gestational age at delivery. In the most recent period, there were significantly more TTTS Quintero stage I treated with laser, more coagulation by the Solomon technique and a larger number of coagulated vessels.

CONCLUSION

The neonatal survival of TTTS is improved by fetoscopic laser coagulation, preferely by using Solomon tecnhique. The use of active management of stage I is currently on research.

Developmental and behavioral outcomes of uncomplicated monochorionic diamniotic twins born in the third trimester

BACKGROUND

Relatively little is known about the neurodevelopmental and behavioral outcomes of monochorionic diamniotic (MCDA) twin pregnancies where there are no antenatal complications peculiar to monochorionicity or prematurity.

METHODS

Twenty-two MCDA twins (44 children) with an average age of 4.3 years, and with no antenatal complications detected by 28 weeks of gestation, were recruited from a feto-maternal unit database. Parents completed a battery of neurodevelopmental and behavioral assessment questionnaires.

RESULTS

Eighteen children (41%) were identified as having developmental or behavioral concerns, predominantly of mild severity, which in turn were associated with a lower birth weight of medium effect size (Cohen's d=0.59).

CONCLUSION

MCDA twins delivered in the third trimester with no antenatal monochorionic complications in the first two trimesters appear to be at risk for subtle neurodevelopmental difficulties, associated with a lower birth weight. Ongoing developmental surveillance of these children during preschool-age is indicated for early identification and intervention.

Changes in ductus venosus flow profile in twin-twin transfusion syndrome: role in risk stratification

OBJECTIVES

To evaluate changes in ductus venosus (DV) waveforms and the timing of these changes in twin-twin transfusion syndrome (TTTS), to relate these to disease severity and to assess the clinical applicability of the suggested measurements in the prediction of TTTS.

METHODS

DV time intervals and velocity-time integrals (VTI) normalized to cardiac cycle and total VTI, respectively, as well as velocity ratios were analyzed in 149 monochorionic diamniotic (MCDA) twin pairs. Pregnancies were assigned to the following groups: uncomplicated MCDA (n = 29); TTTS Stages I+II (n = 50); TTTS Stages III+IV (n = 49); and pre-TTTS (n = 21), of which 14 remained stable and seven progressed to TTTS. Intertwin differences were calculated as larger/recipient minus smaller/donor and related to disease severity. Receiver-operating characteristics curve analysis was used to distinguish TTTS vs uncomplicated MCDA and pre-TTTS progressing to TTTS vs non-progressing pre-TTTS. Intra- and interobserver reliability of measurement of DV parameters were evaluated using intraclass correlation coefficients (ICCs).

RESULTS

No intertwin differences in DV parameters were found in uncomplicated MCDA pregnancies. Diastolic VTIs and filling times were significantly shorter in recipient twins in TTTS cases and in larger pre-TTTS twins in comparison with their cotwins. Time intervals, VTIs and velocity ratios correlated significantly with Quintero stages. An intertwin difference in early filling time (eT) normalized to cardiac cycle, eT (%) ≤ -3.6%, could differentiate TTTS from uncomplicated MCDA pregnancies (82.8% sensitivity; 79.8% specificity) and eT (%) ≤ -2.8% predicted progression to TTTS (73.1% sensitivity; 67.4% specificity).

CONCLUSIONS

DV flow profiles and timing of waveform events are already altered in pre-TTTS and early-stage disease, reflecting abnormal ventricular filling and circulatory imbalance. Intertwin comparison of filling times and VTI may allow prediction of evolving TTTS in MCDA pregnancies. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

North American Fetal Therapy Network: intervention vs expectant management for stage I twin-twin transfusion syndrome

BACKGROUND

Stage I twin-twin transfusion syndrome presents a management dilemma. Intervention may lead to procedure-related complications while expectant management risks deterioration. Insufficient data exist to inform decision-making.

OBJECTIVE

The aim of this retrospective observational study was to describe the natural history of stage I twin-twin transfusion syndrome, to assess for predictors of disease behavior, and to compare pregnancy outcomes after intervention at stage I vs expectant management.

STUDY DESIGN

Ten North American Fetal Therapy Network centers submitted well-documented cases of stage I twin-twin transfusion syndrome for analysis. Cases were retrospectively divided into 3 management strategies: those managed expectantly, those who underwent amnioreduction at stage I, and those who underwent laser therapy at stage I. Outcomes were categorized as no survivors, 1 survivor, 2 survivors, or at least 1 survivor to live birth, and good (twin live birth ≥30.0 weeks), mixed (single fetal demise or delivery between 26.0-29.9 weeks), and poor (double fetal demise or delivery <26.0 weeks) pregnancy outcomes. Outcomes were analyzed by initial management strategy.

RESULTS

A total of 124 cases of stage I twin-twin transfusion syndrome were studied. In all, 49 (40%) cases were managed expectantly while 30 (24%) underwent amnioreduction and 45 (36%) underwent laser therapy at stage I. The overall fetal mortality rate was 20.2% (50 of 248 fetuses). Of those managed expectantly, 11 patients regressed (22%), 4 remained stage I (8%), 29 advanced in stage (60%), and 5 experienced spontaneous previable preterm birth (10%) during observation. The mean number of days from diagnosis of stage I to a change in status (progression, regression, loss, or delivery) was 11.1 (SD 14.3) days. Intervention by amniocentesis or laser therapy was associated with a lower risk of fetal loss (P = .01) than expectant management. The unadjusted odds of poor outcome were 0.33 (95% confidence interval, 0.09-01.20), for amnioreduction and 0.26 (95% confidence interval, 0.09-0.77) for laser therapy vs expectant management. Adjusting for nulliparity, recipient maximum vertical pocket, gestational age at diagnosis, and placenta location had negligible effect. Both amnioreduction and laser therapy at stage I decreased the likelihood of no survivors (odds ratio, 0.11; 95% confidence interval, 0.02-0.68 and odds ratio, 0.07; 95% confidence interval, 0.01-0.37, respectively). Only laser therapy, however, was protective against poor outcome in our data (odds ratio, 0.29; 95% confidence interval, 0.07-1.30 for amnioreduction vs odds ratio, 0.12, 95% confidence interval, 0.03-0.44 for laser), although the estimate for amnioreduction suggests a protective effect.

CONCLUSION

Stage I twin-twin transfusion syndrome was associated with substantial fetal mortality. Spontaneous resolution was observed, although the majority of expectantly managed cases progressed. Progression was associated with a worse prognosis. Both amnioreduction and laser therapy decreased the chance of no survivors, and laser was particularly protective against poor outcome independent of multiple factors. Further studies are justified to corroborate these findings and to further define risk stratification and surveillance strategies for stage I disease.

The History of Treatment of Twin-to-Twin Transfusion Syndrome

Historical suggestions of twin-to-twin transfusion syndrome (TTTS) date back to the early 17th century. Placental anastomoses were first reported in 1687; however, it was Schatz who first identified their importance in 1875. He recognized ‘the area of transfusion’ within the ‘villous district’ of the placenta, which he named the ‘third circulation’. This article describes how the management of TTTS has evolved as we have gained a more sophisticated understanding and appreciation of the complex vascular anastomoses that exist in monochorionic twin placentae. Currently, fetosopic laser occlusion is the preferred treatment option for TTTS.

Evolution of Stage 1 Twin-to-Twin Transfusion Syndrome (TTTS): Systematic Review and Meta-Analysis

Objectives: The natural history of stage 1 Twin-to-twin transfusion syndrome (TTTS) remains unclear and its optimal management is yet to be established. The main aims of this meta-analysis were to quantify the incidence of progression in stage 1 TTTS and to ascertain survival in these pregnancies.

Methods: MEDLINE, EMBASE, and The Cochrane Library were searched. Reference lists within each article were hand-searched for additional reports. The outcomes included incidence of progression and survival in stage 1 TTTS. Randomized controlled trials, cohort and case-control studies were included. Case reports, studies including three or fewer cases of stage 1 TTTS, and editorials were excluded. Proportion meta-analysis was used for analysis (Registration number: CRD42016036190).

Results: The search yielded 3,085 citations; 18 studies were included in the review (172 pregnancies to assess progression and 433 pregnancies to assess the survival). The pooled incidence of progression in stage 1 TTTS was 27% [95% CI 16–39%]. The pooled overall survival, double survival and at least one survival in the pregnancies managed expectantly were 79% [95% CI 62–92%], 70% [95% CI 54–84%] and 87% [95% CI 69–98%], respectively. In those undergoing amnioreduction, the corresponding figures were 77% [95% CI 68–85%], 67% [95% CI 57–76%] and 86% [95% CI 76–94%], respectively. The survival rates were 68% [95% CI 54–81%], 54% [95% CI 36–72%], and 81% [95% CI 69–90%], when laser surgery was performed.

Conclusions: The optimal initial management of stage 1 TTTS remains in equipoise. The ongoing randomized trial comparing immediate laser surgery versus conservative management should provide a definitive answer.

Cardiac Manifestations of Twin–to–Twin Transfusion Syndrome

This review addresses the physiology of monochorionic diamniotic (MC/DA) twins and the potential for twin–twin transfusion syndrome (TTTS). It focuses on the underlying cardiovascular pathophysiology of TTTS and the cardiovascular impact of TTTS for both the recipient and the donor twin. It explains the principles for assessment and monitoring of these cardiovascular changes and how these may be used to guide pregnancy management. Finally, it describes the effect of treatment on the altered hemodynamics and how this can influence pregnancy and perinatal management, as well as longer-term follow-up.

Twin-to-Twin Transfusion Syndrome: From Observational Evidence to Randomized Controlled Trials

Fetoscopic surgery is widely accepted as the preferred first-line treatment for twin-twin transfusion syndrome (TTTS). Nonetheless, the broad diffusion of this technique relies on a single multicentric-randomized trial. We hereby question this trial in a post-hoc Bayesian analysis, submitting its results to several scenarios comprising the alternative published non-randomized literature and pessimistic opinions regarding this surgery. Furthermore, we also discuss further refinements in indications, questioning potential alternatives in early stages of the disease.

Diastolic dysfunction and cerebrovascular redistribution precede overt recipient twin cardiomyopathy in early-stage twin-twin transfusion syndrome

BACKGROUND

Indications for intervention in early-stage (Quintero I and II) twin-twin transfusion syndrome (TTTS) are not standardized. Fetal echocardiography can be used to guide the management of early-stage patients. The aim of this study was to identify early cardiovascular findings that may precede progression to overt recipient twin (RT) cardiomyopathy in early-stage TTTS.

METHODS

This was a retrospective review of pregnancies evaluated from 2004 to 2010. Subjects were included when initial evaluation identified Quintero I or II TTTS without evidence of "overt" RT cardiomyopathy, defined on the basis of atrioventricular valve regurgitation, ventricular hypertrophy, and abnormal Doppler myocardial performance indices. Patients elected management with observation or amnioreduction. Pregnancies were grouped by whether the RT developed overt cardiomyopathy. Initial values, including myocardial performance index, diastolic filling time corrected for heart rate (Doppler inflow duration/cardiac cycle length), pulsatility indices of the ductus venosus, umbilical artery, and middle cerebral artery, and cerebroplacental ratio (middle cerebral artery PI/umbilical artery PI), were compared.

RESULTS

Of 174 pregnancies evaluated with early-stage TTTS, 45 (26%) did not show evidence of RT cardiomyopathy. Follow-up echocardiography identified cardiomyopathy in 20 of 45 RTs (44%). Those RTs with subsequent cardiomyopathy had shorter diastolic filling times corrected for heart rate, higher ductus venosus PIs, lower middle cerebral artery PIs, and lower cerebroplacental ratios on initial echocardiography.

CONCLUSION

Diastolic dysfunction and cerebroplacental redistribution precede findings of overt cardiomyopathy in RTs with early-stage TTTS. Assessment of these parameters may allow earlier identification of RTs with cardiac disease and help guide management. Prospective studies are needed to assess the role of echocardiography in patient selection for the treatment of early-stage TTTS.

Complicated multiple pregnancy referral, treatment and outcomes at the NSW Fetal Therapy Centre

Objectives: To determine the indications for referral, sonographic workload, diagnoses and outcomes of women with a multiple pregnancy referred to the New South Wales Fetal Therapy Centre (NSW FTC). Methods: Retrospective cohort study of twin and higher order multiple (HOM) pregnancies referred to the NSW FTC at the Royal Hospital for Women (RHW) Department of Maternal Fetal Medicine (MFM), Sydney from January 2007 to December 2009.

Results: There were 176 twin pregnancies (138 monochorionic diamniotic, 29 dichorionic diamniotic and nine monoamniotic), and 26 HOMs referred (23 triplet and three quadruplet pregnancies). Indications for referral were: twin to twin transfusion syndrome (TTTS) 103 women, fetal anomaly 31 women, intrauterine growth restriction (IUGR) 12 women, serial surveillance of twins or HOM 37 women, and fetal reduction of HOM (nine women). In 80.2% the pathological referral diagnosis was confirmed. The average number of ultrasounds was five (range 1–24), with 90 women (45%) receiving invasive therapy. Thirty‐five percent (71) of referrals were from outside Sydney, including eight interstate and 11 overseas referrals. Two‐thirds of out of area referrals were able to return to their referral hospital for birth: 95 women (47%) delivered at RHW.

Conclusion: TTTS was the most common reason for referral, with a high concordance between referral and initial diagnosis. RHW accepted a large number of out of area referrals, in keeping with its role as the NSW FTC. Twin and HOM pregnancy referrals represent a significant workload for the 5 department, with many women also requiring invasive therapy.

Stage-related outcome after fetoscopic laser ablation in twin-to-twin transfusion syndrome

AIM

To review the perinatal outcome of twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser coagulation in a developing country with detailed analysis according to the stage of the syndrome.

METHODS

This was a retrospective study of 85 TTTS cases treated with fetoscopic laser coagulation at the Fetal Diagnosis and Treatment Unit of Istanbul Faculty of Medicine between January 2006 and March 2013.

RESULTS

The surgical failure rate was 5.8% (5/85). Among all the cases of the total cohort, only 1 fetus survived in 27 pregnancies (31.8%), and both fetuses survived in 22 pregnancies (25.9%). In 49 pregnancies (57.6%) at least one fetus survived at the end of the neonatal period. The overall survival and live birth rates were 41.8% (71/170) and 56.4% (96/170), respectively, and they significantly decreased as the stage of disease increased. Delivery occurred before 32 weeks of gestation in 54 (63.5%) pregnancies. Logistic regression analysis showed that gestational age at delivery was the only independent factor, and the risk of nonsurvival significantly decreased with increasing age.

CONCLUSION

Based on our experience, the outcome of fetoscopic laser coagulation of the placental anastomoses for TTTS became worse as the Quintero stage of the disease advanced.

Fetoscopic laser therapy for twin-to-twin transfusion syndrome

Twin-to-twin transfusion syndrome (TTTS) is a unique and complicated phenomenon occurring in 10-15% of monochorionic gestations. The chronic unbalanced distribution of blood volume across placental anastomoses between the donor and recipient fetuses leads to multisystem organ impairment including maladaptive changes in both fetuses. Fetoscopic selective laser photocoagulation (SLPC) is now established as the primary treatment modality for advanced stages of TTTS. SLPC is also associated with a risk reduction in fetal demise and long-term neurological impairment.

Twin-twin transfusion syndrome

OBJECTIVE

We sought to review the natural history, pathophysiology, diagnosis, and treatment options for twin-twin transfusion syndrome (TTTS).

METHODS

A systematic review was performed using MEDLINE database, PubMed, EMBASE, and Cochrane Library. The search was restricted to English-language articles published from 1966 through July 2012. Priority was given to articles reporting original research, in particular randomized controlled trials, although review articles and commentaries also were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion in this document. Evidence reports and guidelines published by organizations or institutions such as the National Institutes of Health, Agency for Health Research and Quality, American College of Obstetricians and Gynecologists, and Society for Maternal-Fetal Medicine were also reviewed, and additional studies were located by reviewing bibliographies of identified articles. Consistent with US Preventive Task Force guidelines, references were evaluated for quality based on the highest level of evidence, and recommendations were graded accordingly.

RESULTS AND RECOMMENDATIONS

TTTS is a serious condition that can complicate 8-10% of twin pregnancies with monochorionic diamniotic (MCDA) placentation. The diagnosis of TTTS requires 2 criteria: (1) the presence of a MCDA pregnancy; and (2) the presence of oligohydramnios (defined as a maximal vertical pocket of <2 cm) in one sac, and of polyhydramnios (a maximal vertical pocket of >8 cm) in the other sac. The Quintero staging system appears to be a useful tool for describing the severity of TTTS in a standardized fashion. Serial sonographic evaluation should be considered for all twins with MCDA placentation, usually beginning at around 16 weeks and continuing about every 2 weeks until delivery. Screening for congenital heart disease is warranted in all monochorionic twins, in particular those complicated by TTTS. Extensive counseling should be provided to patients with pregnancies complicated by TTTS including natural history of the disease, as well as management options and their risks and benefits. The natural history of stage I TTTS is that more than three-fourths of cases remain stable or regress without invasive intervention, with perinatal survival of about 86%. Therefore, many patients with stage I TTTS may often be managed expectantly. The natural history of advanced (eg, stage ≥III) TTTS is bleak, with a reported perinatal loss rate of 70-100%, particularly when it presents <26 weeks. Fetoscopic laser photocoagulation of placental anastomoses is considered by most experts to be the best available approach for stages II, III, and IV TTTS in continuing pregnancies at <26 weeks, but the metaanalysis data show no significant survival benefit, and the long-term neurologic outcomes in the Eurofetus trial were not different than in nonlaser-treated controls. Even laser-treated TTTS is associated with a perinatal mortality rate of 30-50%, and a 5-20% chance of long-term neurologic handicap. Steroids for fetal maturation should be considered at 24 0/7 to 33 6/7 weeks, particularly in pregnancies complicated by stage ≥III TTTS, and those undergoing invasive interventions.

Prevalence and progression of recipient-twin cardiomyopathy in early-stage twin-twin transfusion syndrome

OBJECTIVE

The management of twin-twin transfusion syndrome (TTTS) in its early stages (Quintero Stages I and II) is controversial. We describe the prevalence, severity, incidence and rate of progression of recipient-twin cardiomyopathy in Stages I and II TTTS.

METHODS

Among 451 cases of TTTS evaluated between 2004 and 2009, 123 (27.3%) cases of Stages I and II were reviewed. Echocardiography was used to 'upstage' cases based on the presence or absence of mild (IIIA), moderate (IIIB), or severe (IIIC) recipient cardiomyopathy. Progression was defined by worsening in the degree of recipient-twin cardiomyopathy from initial presentation or failure to respond to amnioreduction. Outcome data included progression of recipient-twin cardiomyopathy, treatment and survival to birth. Data were compared by the chi-square, Fisher's exact test or t-test as appropriate.

RESULTS

Seventy-seven of 123 (62.6%) cases were Quintero Stage I and 46/123 (37.4%) Quintero Stage II. Eighty (65.0%) were upstaged to Cincinnati Stage IIIA (n = 25), IIIB (n = 23) or IIIC (n = 32). Management included observation in 11 (8.9%), amnioreduction in 26 (21.1%), amnioreduction followed by selective fetoscopic laser photocoagulation (SFLP) in 43 (35.0%) and primary SFLP in 43 (35.0%). Of 80 cases managed by observation or amnioreduction initially, 43 (53.8%) progressed within a mean duration of 1.4 ± 1.5 weeks. The incidence of progression increased significantly as degree of recipient-twin cardiomyopathy at presentation worsened: Stage I, 9/27 (33.3%); Stage II, 8/15 (53.3%); Stage IIIA, 8/16 (50.0%); Stage IIIB, 10/10 (100%); and Stage IIIC, 8/12 (66.7%) (χ(2) = 14, P < 0.01). Overall fetal survival was 205 out of 244 (84.0%). Fetal survival with observation only was 81.8% (18/22), with amnioreduction only it was 92.3% (48/52), with initial observation or amnioreduction followed by SFLP it was 86.9% (73/84) and with primary SFLP it was 76.7% (66/86).

CONCLUSION

Echocardiography demonstrates a high incidence of recipient-twin cardiomyopathy in early-stage TTTS. The more advanced the recipient-twin cardiomyopathy is, the more likely is progression to occur during observation or following amnioreduction.

Long-term morbidity after fetal endoscopic surgery for severe twin-to-twin transfusion syndrome

BACKGROUND/PURPOSE

Severe twin-to-twin transfusion syndrome (TTTS) leads to 80% to 100% dual mortality. Endoscopic laser coagulation of connecting vessels improves outcome to 80% survival of at least 1 twin. There is limited long-term follow-up of surviving TTTS patients. The aim of this study was to analyze gestational age-stratified, long-term morbidity in these patients.

METHODS

A retrospective case-control study of TTTS surviving patients (38 patients, 72% follow-up rate) from one center. Perinatal and pediatric records were reviewed, and outcomes were compared with published reports and gestational age-matched controls.

RESULTS

Forty percent (15/38) had at least 1 major sequela, all but 6 of which were fully resolved at a median follow-up of 4.4 years. There were no permanent cardiac, genitourinary, renal, or respiratory sequelae. All major complications were in patients born <29 weeks. There were no significant differences in complications between this cohort of patients and gestational age (GA)-matched control patients.

CONCLUSIONS

The long-term morbidity of monochorionic twins after fetal laser surgery for severe TTTS is 13%. At a median follow-up of more than 4 years, these children fare no worse than gestational age-matched, non-operated twins and singletons. The degree of prematurity at birth is the best predictor of temporary or permanent sequela in this group of patients.

Laser therapy for twin-to-twin transfusion syndrome (TTTS)

Monochorionic twins are subjected to specific complications which originate in either imbalance or abnormality of the single placenta serving two twins including twin-to-twin transfusion syndrome. The diagnosis is well established in overt clinical forms with the association of polyuric polyhydramnios and oliguric oligohydramnios. The best treatment of cases presenting before 26 weeks of gestion is fetoscopic laser ablation of the intertwin anastomoses on the chorionic plate. Although subjected to subtle variations, the core technique follows robust guidelines which could help understanding and acquiring the required skills and experience to perform this procedure. However appropriate and tailored hands-on training and appropriate perinatal set-up are critical not only for surgical management but also for the follow-up and management of related complications.

[Fetoscopic laser coagulation in 100 consecutive monochorionic pregnancies with severe twin-to-twin transfusion syndrome]

OBJECTIVES

To report pre- and post-surgical datas of large series of severe twin-to-twin transfusion syndrome (TTTS) managed with laser ablation surgery in our centre, to evaluate the incidence of complications, perinatal outcome and to compare with other cohorts.

PATIENTS AND METHODS

Observational study of 100 cases of TTTS consecutively treated with fetoscopic laser coagulation between January 2004 and April 2010 in CMCO-SIHCUS of Schiltigheim.

RESULTS

There are nine stage I, 49 stage II, 38 stage III and four stage 4. Median gestation at time of laser is 20.6 weeks (14-29) whereas median gestation at delivery is 32.6 weeks (16.3-39). Overall perinatal survival rate is 68.5% (137 children over 200). Eighty-five percent have one or more surviving twins. The survival rate is the same for donors and for recipients. Preterm premature rupture of the membranes are observed in 17% of cases and the median gestational age for this complication is 30 weeks (20-34). Cerebral abnormalities are present in 7% of newborns.

CONCLUSION

Our results for the management of severe TTTS are comparable to the other reported series. There are still many questions remaining concerning the optimal management of TTTS.

Twin-to-twin transfusion syndrome (TTTS)

Twin-to-twin transfusion syndrome (TTTS) is a severe complication of monochorionic (MC) twin pregnancies, characterized by the development of unbalanced chronic blood transfer from one twin, defined as donor twin, to the other, defined as recipient, through placental anastomoses. If left untreated, TTTS is associated with very high perinatal mortality and morbidity rates, due to a combination of fetal and/or obstetric complications. The reported prevalence is 10-15% of all MC twins, or about 1 in 2000 pregnancies. This consensus document reviews available evidence and offers practical guidance to clinicians by providing recommendations on various aspects concerning diagnosis and management of TTTS.

New and/or improved aspects of fetal surgery

Open fetal surgery through a wide hysterotomy is no longer a real option for prenatal intervention, but a minimally invasive approach has emerged as treatment for a small number of indications. Endoscopic ablation of placental vessels is the preferred treatment for severe twin-to-twin transfusion syndrome and it may be the only chance to salvage the most severe forms of congenital diaphragmatic hernia. Several other indications are currently under review and may become justified in the future, provided that diagnostic accuracy and patient selection become more accurate. Before invasive fetal intervention becomes widely accepted, however, we need to better define outcome. It is no longer acceptable to express results in terms of survival at birth. Survival at discharge and long-term morbidity must be considered as well.

Specific complications of monochorionic twin pregnancies: twin-twin transfusion syndrome and twin reversed arterial perfusion sequence

Monochorionic twins are subjected to specific complications which originate in either imbalance or abnormality of the single placenta serving two twins. This unequal placental sharing can cause complications including twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence (TAPS), selective intrauterine growth restriction or twin reversed arterial perfusion sequence (TRAP). Monochorionicity also makes the management of these specific complications as well as that of a severe malformation in one twin hazardous since the spontaneous death of one twin exposes the co-twin to a risk of exsanguination into the dead twin and its placenta. The latter is responsible for the death of the co-twin in up to 20% of the cases and in ischemic sequelae in about the same proportions in the survivors. Although the symptoms of all these complications are very different, the keystone of their management comes down to either surgical destruction of the inter-twin anastomoses on the chorionic plate when aiming at dual survival or selective and permanent occlusion of the cord of a severely affected twin aiming at protecting the normal co-twin. This can be best achieved by fetoscopic selective laser coagulation and bipolar forceps cord coagulation respectively.

Management of Stage I twin-to-twin transfusion syndrome: an international survey

OBJECTIVE

To determine practice patterns for evaluation and treatment of Stage I twin-to-twin transfusion syndrome (TTTS) among international physicians.

METHODS

An e-mail cross-sectional survey of members from the IFMSS, NAFTNet and SMFM societies and participants at a Eurofoetus-sponsored TTTS meeting was undertaken between May 2008 and November 2008. Questionnaires consisted of physician demographics and their recommendations for managing Stage I TTTS. Alternative therapies to expectant management were assessed based on the following special circumstances of the patient: residence more than 200 miles from the center, severe symptoms, or a cervical length of </= 15 mm.

RESULTS

Eighty-one surveys were returned, giving a response rate of 84%. Five surveys were excluded as a result of duplication or missing data. Of the remaining 76 surveys, 48 were from North America, 20 were from Europe and eight were from other continents. Expectant management was the predominant recommendation (78%), followed by amnioreduction (11%), laser ablation (11%) and septostomy (1%). Recommendations for amnioreduction were exclusively from North American centers. Laser centers recommended expectant management more frequently than non-laser facilities (89% vs. 59%; P < 0.01). When examples of special patient circumstances were presented, North American centers changed their recommendation from expectant management to amnioreduction more often than did European centers. However, a greater proportion of European centers recommended laser surgery for special patient circumstances.

CONCLUSION

Expectant management remains the predominant management of Stage I TTTS. In some patient circumstances, North American centers are more likely to recommend amnioreduction while European centers are more likely to recommend laser therapy. A randomized controlled trial will be necessary to evaluate the most efficacious management strategy for Stage I TTTS.

Outcomes in a cohort of patients with Stage I twin-to-twin transfusion syndrome

OBJECTIVE

To determine pregnancy outcomes of patients who present with Stage I twin-to-twin transfusion syndrome (TTTS).

METHODS

This was a retrospective review of all patients with TTTS referred to our institution between January 2005 and December 2006. Quintero criteria were used for staging. Laser ablation was not offered to patients with Stage I disease.

RESULTS

A total of 155 twin pregnancies were evaluated for TTTS during this period. Forty-two met the criteria for Stage I and were included in the analysis. The overall survival to discharge was 82%. The mean gestational age at the time of consultation was 20.9 +/- 0.4 weeks. A total of 23 cases (54.8%) underwent amnioreduction. Progression of TTTS requiring invasive therapy occurred in four cases. The mean gestational age at delivery was 32.5 +/- 0.62 weeks. When divided according to use of amnioreduction, there were no statistically significant differences between the groups for gestational age at delivery or for birth weight. Those Stage I cases with a CHOP cardiovascular score of 5 or higher delivered almost 3 weeks earlier than the remainder of the cohort.

CONCLUSIONS

Progression of TTTS beyond Stage I occurred in only 9.5% of the cohort. Mean gestational age at delivery and survival to discharge did not differ between Stage I patients and those treated with placental laser ablation for more advanced stages of TTTS.

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.

Twin-to-twin transfusion syndrome: current understanding of pathophysiology, in-utero therapy and impact for future development

Whereas monochorionic twins account for only 30% of twin gestations, they contribute to a disproportionate extent to the overall twin perinatal morbidity and mortality. Twin-to-twin transfusion syndrome can occur at any point in a monochorionic gestation but is associated with significant increases in both morbidity and mortality when it develops before 26 weeks of gestation. It is still not possible to predict accurately those pregnancies that will be affected. This has resulted in the practice of routine ultrasound surveillance beginning at the end of the first trimester. Our understanding of the physiology still has many gaps but there is an increased recognition of the heterogeneity that exists especially in the early stages of the disease. The role of the cardiovascular response of the recipient twin offers the potential for further refining the application of our current treatment modalities and may offer insight into future therapies. The optimal therapy at this point in time resides clearly with selective laser photocoagulation, and further refinements of techniques and patient selection may continue to improve outcomes. Finally, the in-utero responses generated by the fetuses to the physiologic stress of twin-to-twin transfusion may influence their response or ability to respond to cardiovascular stress in later life. If there is in-utero programming, then the detection and timely treatment of conditions such as twin-twin transfusion syndrome may have lifelong implications for both members of the twin pair.

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.

The pediatric surgeons' contribution to in utero treatment of twin-to-twin transfusion syndrome

OBJECTIVE

To evaluate the outcome of twin-to-twin transfusion syndrome (TTTS) treated using a combination of endoscopic fetal surgery-specific techniques and surgical restraint.

SUMMARY BACKGROUND DATA

TTTS is a condition of identical twins that, if progressive and left untreated, leads to 100% mortality. The best treatment option is obliteration of the intertwin placental anastomoses, but fetal surgery carries significant maternal and fetal risks. Even if successful, percutaneous endoscopic laser ablation of placental vessels (LASER) causes premature rupture of membranes (PROM) in 10% to 20% of pregnancies. Patient selection is particularly critical because the progression of the disease is unpredictable. This has prompted many to intervene early, yielding survival rates of >=1 twin of 75% to 80%.

METHODS

We developed a minimally invasive approach to fetal surgery, a unique membrane sealing technique and a conservative algorithm that reserves intervention for severe TTTS. Pregnancies with TTTS (stages I-IV) managed in the last 8 years were reviewed. LASER was offered in stage III/IV only.

RESULTS

Ninety-eight cases of TTTS were managed in a pediatric surgery/maternal-fetal medicine collaborative Fetal Treatment Program-39 were observed (40%) and 59 underwent LASER (60%). Survival of >= twin was seen in 82.7%, and overall survival was 69.4%. These survival rates are similar to, or better than, other comparable series with similar stage distribution (low:high stage ratio 1:1) in which all patients underwent LASER. PROM rate was 4%.

CONCLUSIONS

Reserving LASER treatment for severe TTTS results in outcomes similar to, or better than, LASER for all stages. Applying fetal surgery-specific endoscopic techniques, including port-site sealing, reduces postoperative complications.