A nomogram for perioperative prognostic risk-assessment in twin-twin transfusion syndrome

Pregnancy outcomes following early fetoscopic laser photocoagulation for twin-to-twin transfusion syndrome at 16 weeks' gestation

BACKGROUND

Ample evidence supports fetoscopic laser photocoagulation of placental anastomoses as a first-line treatment for twin-to-twin transfusion syndrome, but little is known about the outcomes following procedures conducted in the early second trimester.

OBJECTIVE

This study aimed to evaluate perinatal outcomes following early fetoscopic laser placental photocoagulation performed for twin-to-twin transfusion syndrome at 16 weeks' gestation.

STUDY DESIGN

This retrospective review included monochorionic twin pregnancies complicated by twin-to-twin transfusion syndrome necessitating fetoscopic laser photocoagulation at a single tertiary center from 2012 to 2021. The 2 cohorts were defined as cases undergoing laser surgery at 16+0/7 to 16+6/7 weeks' gestation (early laser group) and those undergoing laser surgery ≥17 weeks' gestation (standard laser group), respectively. Primary outcomes included rates of immediate chorioamniotic membrane separation, preterm premature rupture of membranes, and clinical chorioamnionitis. Secondary outcomes included twin survival rates at birth and 30 days of life. Outcomes were compared between cohorts with a P value of <.05 denoting statistical significance.

RESULTS

A total of 343 cases were included (35 early laser participants and 308 standard laser participants). The early laser group typically had higher Quintero staging at the time of the procedure. Following intervention, the early laser group had significantly higher rates of chorioamniotic separation than the standard laser group (34.3% vs 1.3% of cases; P<.001) and higher rates of preterm prelabor rupture of membranes (45.7% vs 25.0%; P=.009) and chorioamnionitis (11.4% vs 1.3%; P=.005). Even after adjustment for higher Quintero staging in the early laser group, twin survival was not significantly different between study groups.

CONCLUSION

Early laser surgery for twin-to-twin transfusion syndrome performed at 16 weeks' gestation is associated with significantly higher rates of chorioamniotic separation, preterm rupture of membranes, and chorioamnionitis. However, twin survival does not seem to be negatively impacted following early laser surgery.

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.

Early laser surgery is not associated with very preterm delivery or reduced neonatal survival in TTTS

OBJECTIVE

To evaluate the association of laser photocoagulation of placental anastomoses (LPA) prior to 18 weeks' gestation (early LPA) with very preterm delivery and neonatal survival in pregnancies with twin-twin transfusion syndrome (TTTS).

METHODS

This was a retrospective cohort study of monochorionic diamniotic twin pregnancies with TTTS undergoing LPA between 2002 and 2018 at two institutions. The rates of delivery < 28, < 30 and < 32 weeks' gestation, preterm prelabor rupture of membranes (PPROM) and 30-day survival of one or both infants were compared between pregnancies undergoing early LPA and those undergoing LPA ≥ 18 weeks' gestation. Regression analysis was performed to determine the association of early LPA with very preterm delivery and 30-day survival, adjusted for Quintero stage, study phase, selective fetal growth restriction, gestational age at delivery, maternal age ≥ 35 years, body mass index > 35 kg/m² , placental location, use of Seldinger method to place the operative trocar, size of the trocar, participating center, use of Solomon technique, cerclage and PPROM. Survival analysis using the Cox proportional hazard model was applied to examine the LPA-to-delivery interval according to the timing of surgery, adjusted for confounding variables.

RESULTS

A total of 414 TTTS pregnancies were included in the study, of which 68 (16.4%) underwent early LPA. In the total cohort, the incidence of delivery at < 28, < 30 and < 32 weeks' gestation was 22.7%, 39.6% and 53.4%, respectively. Survival of both twins and survival of at least one twin at 30 days were 67.5% and 90.8%, respectively. No significant difference was noted between pregnancies that underwent early LPA and those that had LPA ≥ 18 weeks in the rate of delivery < 28 weeks (19.1% vs 23.4%; P = 0.4), < 30 weeks (38.2% vs 39.9%; P = 0.8) and < 32 weeks (44.1% vs 55.2%; P = 0.1) and PPROM (29.0% vs 24.1%; P = 0.4), or in the incidence of double-twin survival (63.9% vs 68.1%; P = 0.5) and survival of at least one infant (91.8% vs 90.6%; P = 0.7) at 30 days. Early LPA was not associated with very preterm delivery or neonatal survival in the regression analyses. Early LPA was associated with a longer LPA-to-delivery interval compared with LPA performed ≥ 18 weeks (median, 106.9 days (range, 2-164 days) vs median, 69.3 days (range, 0-146 days); P < 0.001) when adjusted for confounding variables (hazard ratio, 2.56 (95% CI, 1.76-3.73); P < 0.001).

CONCLUSION

Laser surgery before 18 weeks is not associated with an increased rate of very preterm delivery and PPROM or with reduced neonatal survival when compared with LPA after 18 weeks. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal Growth in Multiple Gestations: Evaluation and Management

Multifetal gestation pregnancies present a clinical challenge due to unique complications including growth issues, prematurity, maternal risk, and pathologic processes, such as selective intrauterine growth restriction (sIUGR), twin-to-twin transfusion syndrome (TTTS), and twin anemia-polycythemia sequence. If sIUGR is found, then management may involve some combination of increased surveillance, fetal procedures, and/or delivery. The combination of sIUGR with TTTS or other comorbidities increases the risk of pregnancy complications. Multifetal pregnancy reduction is an option when a problem is confined to a single fetus or when weighing the risks and benefits of a multifetal gestation in comparison to a singleton pregnancy.

Fetal Survival Immediate after Fetoscopic Laser Ablation in Twin to Twin Transfusion Syndrome

BACKGROUND

The purpose of this study was to determine prognostic factors that can affect the fetal survival immediate after fetoscopic laser ablation.

METHODS

The study population consisted of consecutive twin pregnant women who underwent fetoscopic laser ablation with the diagnosis of twin to twin transfusion syndrome (TTTS) from 2011 to 2018 in Seoul National University Hospital. Fetal survival immediate after procedure was defined as survival to 48 hours after procedure and neonatal survival was defined as survival to 28 days of life. Clinical characteristics and ultrasound findings were compared according to the fetal survival immediate after procedure.

RESULTS

A total of 57 pregnant women with TTTS were included, and the overall fetal survival immediate after procedure was 71.1% (81/114) after fetoscopic laser ablation. Fetuses who survived immediate after procedure had higher gestational age at procedure and lower frequency of abnormal Doppler studies than those did not survive. However, the frequency of hydrops was not different between cases with fetal survival and those with fetal death. The earlier gestational age at procedure and the presence of abnormal Doppler studies were significant risk factors for fetal death even after adjustment.

CONCLUSION

Based on this data, the fetal survival immediate after procedure (fetoscopic laser treatment) in TTTS can be affected by the gestational age at procedure and the presence of abnormal Doppler studies.

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.

Fetal Doppler changes 1 week after endoscopic equatorial laser for twin-to-twin transfusion syndrome: A longitudinal study

OBJECTIVE

To investigate sequential Doppler changes in donors and recipients before and 1 week after endoscopic laser for twin-to-twin transfusion syndrome (TTTS) and to examine factors that may be associated with such changes.

METHODS

In TTTS pregnancies undergoing laser treatment, we examined fetal Doppler changes before and 1 week postintervention. Intrauterine death rates and preoperative factors were analyzed in relation to Doppler changes.

RESULTS

Among 129 (85.4%) donors surviving at 1 week after laser, there was normalization of umbilical artery flow in 26 (72.2%) of 36 cases with preoperative abnormal Dopplers. In the remaining 10 (27.8%) fetuses, abnormal findings persisted. The rate of later intrauterine death was significantly higher in the latter group (6 of 10, 60.0%) compared with fetuses in which Doppler findings normalized (4 of 26, 15.4%; P < .05), with no difference in the rate of severe donor growth restriction between the 2 groups (80.0% vs 65.4%, respectively; P = .688).

CONCLUSIONS

In about 70% of TTTS donors with preoperative abnormal umbilical artery Doppler, there was normalization 1 week after endoscopic laser. The incidence of fetal growth restriction was not significantly different in donors with persistence of Doppler abnormalities compared with those with normalized findings.

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.

Estimated combined cardiac output and laser therapy for twin-twin transfusion syndrome

INTRODUCTION

Twin-twin transfusion syndrome (TTTS) is the major cause for fetal demise in monochorionic diamniotic pregnancies. Estimated combined cardiac output (CCO) has not been studied in this setting. The primary aims of this study were to compare CCO in twin donor and recipient fetuses and assess differences in CCO before and after laser coagulation therapy. A secondary aim was to evaluate the relationship of CCO with perinatal mortality, defined as intrauterine or neonatal mortality (≤30 days of age) in fetuses that underwent laser coagulation therapy.

METHODS

We performed a retrospective review of fetuses with TTTS who received echocardiograms prior to laser therapy. Prelaser echocardiograms were performed in 66 fetuses, of which 45 (21 donor and 24 recipient) survived to the postlaser echocardiogram.

RESULTS

Donor CCO increased from a mean of 487±137 mL/min/kg prelaser to 592±128 mL/min/kg postlaser (P=.025). There was no significant change in mean recipient CCO from prelaser 551±165 mL/min/kg to postlaser 575±112 mL/min/kg (P=.564). In recipient fetuses, higher prelaser CCO correlated with increasing Quintero stage (P=.010) and perinatal mortality (P=.003). Thirty-day postnatal outcome data were available for 38 fetuses, of whom 34 (89%) survived. Amongst survivors, 25 (74%) experienced an increase in CCO, while 9 (26%) experienced a decrease in CCO (P=.010). Donor fetuses had higher CCO after laser therapy.

CONCLUSIONS

Higher prelaser CCO in recipient fetuses may indicate more advanced disease. Fetuses who exhibit a decrease in CCO after therapy laser may be at higher risk for perinatal mortality.

Postnatal survival after endoscopic equatorial laser for the treatment of twin-to-twin transfusion syndrome

BACKGROUND

Endoscopic laser coagulation of placental anastomoses is the first-line treatment for severe twin-to-twin transfusion syndrome. A recent randomized controlled trial reported that laser coagulation along the entire vascular equator was associated with a similar dual survival and survival of at least 1 twin compared with the group that was treated with the selective technique. In addition, there was a significantly lower incidence of postoperative recurrence of twin-to-twin transfusion syndrome and the development of twin anemia-polycythemia sequence in the equatorial group.

OBJECTIVE

The purpose of this study was to report on neonatal survival in twin-to-twin transfusion syndrome pregnancies that were treated with endoscopic laser therapy with the use of the equatorial technique and to examine the relationship between preoperative factors and twin loss.

STUDY DESIGN

Endoscopic equatorial laser therapy was carried out as the primary treatment for twin-to-twin transfusion syndrome in all consecutive monochorionic diamniotic twin pregnancies that were referred at a single fetal surgery Center over a 4-year period. All visible placental anastomoses were coagulated; additional laser ablation of the placental tissue between the coagulated vessels was carried out. Pre-laser ultrasound data, periprocedural complications, pregnancy outcome, and postnatal survival at hospital discharge were recorded and analyzed.

RESULTS

A total of 106 pregnancies were treated during the study period. Median gestational age at laser therapy was 19.7 weeks (range, 15.1-27.6 weeks). There was postoperative recurrence of twin-to-twin transfusion syndrome or the development of twin anemia-polycythemia sequence in 2 (1.9%) and 2 (1.9%) cases, respectively. The survival rates of both and at least 1 twin were 56.6% and 83.0%, respectively. Donor survival was significantly lower compared with the recipient co-twin (64.2% vs 75.5%, respectively; P < .05). The rate of fetal death, which was the most common cause of twin loss, was significantly higher in donors compared with recipient fetuses (23.6% vs 10.4%, respectively; P < .05). In cases with absent or reversed end-diastolic velocity in the donor umbilical artery, dual and donor survival rates were significantly lower compared with the remaining twin-to-twin transfusion syndrome pregnancies (40.0% vs 64.8% and 40.0% vs 76.1%, respectively; P < .05). There were no significant differences between the 2 groups in the survival of at least 1 twin and in the recipient survival.

CONCLUSIONS

Endoscopic equatorial laser therapy was associated with a survival of both and at least 1 twin of approximately 55% and 83%, respectively, with a low rate of recurrent twin-to-twin transfusion syndrome and twin anemia-polycythemia sequence. In addition, the preoperative finding of abnormal donor umbilical artery Doppler on ultrasound identified a subgroup of twin-to-twin transfusion syndrome pregnancies with a lower dual survival rate caused by increased intrauterine deaths of donor twins.

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.

Outcome following selective fetoscopic laser ablation for twin to twin transfusion syndrome: an 8 year national collaborative experience

OBJECTIVE

With the recognition of the role of fetoscopic laser ablation for twin to twin transfusion syndrome (TTTS), there is a requirement for auditable standards for this technically challenging and specialized treatment. The purpose of this study is to report on the perinatal and medium-term neurodevelopmental outcomes following an 8-year national single center experience in the management of TTTS using the selective fetoscopic laser ablation technique.

STUDY DESIGN

An audit of all cases of TTTS treated with selective laser ablation by a single national fetal medicine team was performed. Overall perinatal survival and medium-term neurodevelopmental outcomes were reported and correlated with gestational age at diagnosis, placental location, volume of amnio-reduction, Quintero staging and percentage inter-twin growth discordance. Procedure-related complications were recorded.

RESULTS

The overall fetal survival for the first 105 consecutive cases of TTTS was 61% (128/210 fetuses). Dual survival occurred in 47% (49/105) of cases, and with a single survival rate of 28% (30/105), perinatal survival of least one infant was achieved in 75% (79/105) of cases. No correlation was found between any clinical or sonographic marker and perinatal outcome, although dual survival was noted to be significantly decreased with increasing Quintero stage (p=0.041). Currently, 86% of survivors have been reported to have a normal medium-term neurological outcome.

CONCLUSION

Fetoscopic laser ablation is the established optimal treatment for severe twin to twin transfusion syndrome (TTTS). We report comparable short and medium-term outcomes following the selective fetoscopic technique comparing results from our national program with internationally published single-center outcomes, supporting the efficacy and safety of this treatment at our center.

Fetoscopic laser coagulation for twin-twin transfusion syndrome before 17 weeks' gestation: laser data, complications and neonatal outcome

OBJECTIVE

To compare laser data, complications and neonatal outcome in pregnancies that undergo 'early' (≤ 17 weeks' gestation) fetoscopic laser ablation of placental vascular anastomoses for twin-twin transfusion syndrome (TTTS) with those from 'conventional' cases treated after 17 weeks.

METHODS

This was a cohort study of data collected prospectively between January 2004 and December 2012. We included monochorionic diamniotic twin pregnancies complicated by TTTS and treated by fetoscopic laser coagulation. Pregnancies were grouped according to laser treatment ≤ 17 gestational weeks or > 17 weeks and obstetric and neonatal outcomes were compared between groups.

RESULTS

A total of 178 pregnancies with TTTS underwent laser therapy: 40 at or before 17 weeks and 138 after 17 weeks. There was no statistically significant difference between these two groups with respect to the rate of preterm prelabor rupture of membranes (PPROM), gestational age at PPROM and rate of PPROM occurring in the 7 days following fetoscopic laser coagulation. In the early group, the interval between performing fetoscopic laser coagulation and the time of delivery was significantly longer (104 days vs 74 days, P=0.0002) and the delivery rate within 7 days of laser treatment was significantly lower (2.5% vs 15.9%, P=0.026). There was no significant difference between the two groups with regard to the rates of pregnancy without live birth (15.4% vs 15.4%, P=0.993), with one live birth (84.6% vs 84.6%, P=0.993) and with two live births (64.1% vs 58.1%, P=0.500).

CONCLUSION

In the event of early TTTS, fetoscopic laser coagulation is technically feasible before 17 gestational weeks and obstetric and neonatal outcomes are comparable with those in cases of laser treatment performed after 17 weeks.

Perioperative characteristics associated with preterm birth in twin-twin transfusion syndrome treated by laser surgery

OBJECTIVE

To identify perioperative risk factors for preterm delivery (PTD) in laser-treated patients with twin-twin transfusion syndrome (TTTS).

STUDY DESIGN

Twin-twin transfusion syndrome patients who underwent laser surgery were followed prospectively. Univariate and multivariate analyses were performed to identify gestational and surgical characteristics associated with preterm delivery.

RESULTS

Of 318 eligible patients, the mean (SD) gestational age of delivery was 32.8 (4.2) weeks. The number of days from laser surgery to delivery had a bimodal distribution; group I delivered within 21 days and group II delivered after 21 days of surgery. Eighteen patients (5.7%) were in group I and demonstrated the following risk factors for delivery within 21 days: incomplete laser surgery suspected (odds ratio [OR], 11.14; P = .0106), preoperative subchorionic hematoma (OR, 7.92, P = .0361), preoperative cervical length <2.0 cm (OR, 4.71; P = .0117), and recipient's maximum vertical pocket ≥14 cm (OR, 3.23; P = .0335). In group II, 92 of 300 patients (30.7%) delivered <32 weeks, and 25 (8.3%) delivered <28 weeks; multivariate logistic regression analyses identified 5 risk factors for delivery <32 weeks: incomplete laser surgery suspected (OR, 10.0; P = .0506); incidental septostomy (OR, 4.4; P = .0009); triplet gestation (OR, 2.6; P = .0689); postoperative membrane detachment (OR, 2.4; P = .0393); and nonposterior placental location (OR, 1.8; P = .0282).

CONCLUSION

Timing of delivery after laser for twin-twin transfusion syndrome has a bimodal distribution with distinct gestational and surgical risk factors. This information may be useful in counseling patients and in directing future avenues of research.