Preoperative prediction of the individualized risk of early fetal death after laser therapy in twin-to-twin transfusion syndrome

The Outcome after Laser Therapy of Monochorionic Twin Pregnancies Complicated by Twin-Twin Transfusion Syndrome with Coexistent Selective Fetal Growth Restriction

Background: Most previous studies evaluated outcomes of twin-twin transfusion syndrome (TTTS) without considering the coexistence of selective fetal growth restriction (sFGR). The objectives of this study were to compare twin survival and pregnancy complications after laser therapy of TTTS with and without sFGR. Methods: For this purpose, a retrospective cohort study including 98 monochorionic diamniotic twins and three dichorionic triamniotic triplets treated in a single tertiary center was conducted. Results: Overall, 46 twins had selective fetal growth restriction (26 type I, 13 type II, 7 type III). At birth, donor survival (61% vs. 91%), double survival (57% vs. 82%), and overall survival (75% vs. 88%) were significantly lower in the group with coexistent sFGR. Recipient survival (89% vs. 86%), miscarriage (7% vs. 2%), PPROM < 32 weeks (48% vs. 29%), and preterm delivery < 32 weeks (52% vs. 45%) were not significantly higher in the group with coexistent sFGR. Donor twins with sFGR type I (69% vs. 91%) and types II-III (50% vs. 91%) showed significantly lower survival than those without sFGR. Multivariate regression analysis identified sFGR and its subtypes as independent predictors of donor demise. Conclusions: the coexistence of sFGR in TTTS pregnancies was associated with poor donor outcomes and is probably the most important predictor of donor survival.

Developmental outcomes for survivors of placental laser photocoagulation for the management of twin-to-twin transfusion syndrome

BACKGROUND

Fetoscopic laser coagulation of placental anastomoses reverses the pathological process in twin-to-twin transfusion syndrome, thereby increasing survival, but there are a paucity of studies addressing long-term neurodevelopmental outcome of survivors. This study aimed to ascertain the presence of neurodevelopmental disabilities in child survivors of monochorionic pregnancies managed by placental laser photocoagulation in the Australian state of Victoria.

METHODS

All pregnancies undergoing placental laser photocoagulation with the Victorian Fetal Therapy Service between 2006-2017 were included. Information on each surviving child, including demographics, perinatal course, and developmental progress was collected from parents, and consent was sought to complete the Child Behaviour Checklist. Interviewers evaluated whether this information was consistent with a diagnosis of any of 14 neurodevelopmental conditions. A three-tiered outcome measure was allocated for each child: (1) unimpaired or developmentally normal, (2) mild or moderate neurological impairment, or (3) severe neurological impairment. Clinical predictors for adverse outcome were identified.

RESULTS

Of 116 pregnancies (113 twin, 3 triplet), 96 (83%) resulted in 1 + surviving fetuses. 57/113 (50%) twin pregnancies resulted in 2 survivors, 36 (32%) in 1 survivor, and 20 (18%) in no survivors. Of the 235 fetuses, 154 (65.5%) survived to follow-up. Survival increased from 59% in 2006-2008 to 73% in 2015-2017. 90/154 (58%) survivors were followed up at a mean age of 7.5 [SD 3.0] years. Based on parental interview and Child Behaviour Checklist data, 28/90 (31%) participants were assessed as having neurodevelopmental impairment, 27 of mild-moderate severity and 1 severe. Speech/language disorders, attention deficit (hyperactivity) disorders, and fine motor impairment were most common. Neonatal length of stay conferred the highest risk of impairment.

CONCLUSION

Substantial variation exists between fetal therapy services in the type and length of neonatal follow-up following fetoscopic laser coagulation, contributing to a lack of data on long-term outcomes. The findings from this study support increasingly urgent calls to undertake systematic and sustained follow-up of fetoscopic laser coagulation survivors until school age. Information from this study may assist parents in their decision-making when offered fetal surgery. Importantly, it highlights a group for targeted surveillance and early intervention.

Fetal Doppler in monochorionic pregnancies complicated by twin-to-twin transfusion syndrome and selective in utero growth restriction

BACKGROUND

Monochorionic (MC) twin pregnancies may be complicated by placental pathologies that impact fetal cardiac function, such as twin-twin transfusion syndrome (TTTS) and selective intrauterine growth-restriction (sIUGR). In the TTTS, the unbalanced blood flow through placental anastomoses lead a recipient volume overload, hypertension and hypertrophic cardiomyopathy and the donor twin experiences hypovolemia and hypertension due to increased placental resistance and poor renal perfusion. When MC pregnancies were complicated by sIUGR, the increase of placental resistances lead to complex fetal compensatory mechanisms with redistribution of cardiac output to vital organs. Increased placental vascular resistances, hypoxia and hemodynamic compensation mechanisms lead to higher pre and/or afterload for both ventricles, right cardiac failure and eventually left cardiac failure observed just before fetal death.

OBJECTIVES

The purpose of this study was to describe the anomalies of umbilical, ductal and aortic isthmic Doppler as well as left and right myocardial performance index (MPI) across various clinical phenotypes of MC twin pregnancies, uncomplicated or complicated by TTTS or sIUGR, in order to help differentiating these conditions and to improve the understanding of TTTS and sIUGR pathophysiology.

STUDY DESIGN

Aortic isthmic systolic index (ISI), umbilical artery pulsatility index (UAPI), ductus venosus pulsatility index (DVPI), and MPI were studied in uncomplicated MC twins (control group) and cases of sIUGR or TTTS.

RESULTS

The measurements were obtained in 113 pregnancies (24 uncomplicated, 22 sIUGR, 51 TTTS). In comparison with controls, the sIUGR smaller twin sets had lower ISI and higher UAPI, and the larger twin had higher ISI. The TTTS donor and recipient had lower ISI, higher UAPI and DVPI. Compared to the co-twin, the ISI values were lower in the sIUGR smaller twin and the TTTS donor had lower ISI and MPI. Comparing TTTS and sIUGR, the recipient had higher DVPI and MPI than the sIUGR larger twin.

CONCLUSIONS

The Doppler anomalies observed in the smaller twin reflected increased placental blood flow resistance, presumably due to abnormal feto-fetal transfusion in TTTS and to unequal placental sharing in sIUGR. Early hemodynamic changes suggestive of cardiac overload in the recipient twin may help to differentiate TTTS and sIUGR.

Single fetal demise following fetoscopic ablation for twin-to-twin transfusion syndrome-cohort study, systematic review, and meta-analysis

BACKGROUND

Several studies have assessed preoperative and operative factors associated with fetal demise after laser for TTTS, yet these findings are not completely conclusive.

OBJECTIVE

This study aimed to identify risk factors for single fetal demise (recipient and donor twins) after fetoscopic laser photocoagulation for twin-to-twin transfusion syndrome.

STUDY DESIGN

We searched PubMed, Scopus, and Web of Science systematically from the inception of the database to June 2020. We conducted a systemic review on studies investigating risk factors for fetal demise (donor and/or recipient) after fetoscopic laser photocoagulation in monochorionic pregnancies complicated with twin-to-twin transfusion syndrome. Initially, we investigated the cohort of women with twin-to-twin transfusion syndrome that underwent fetoscopic laser photocoagulation at our 2 high-volume fetal centers between 2012 and 2020 to identify risk factors for donor demise and recipient demise. Furthermore, we conducted a systematic review of the literature to better characterize these factors. Among studies that met the entry criteria, multiple preoperative and operative factors were tabulated. The random-effect model was used to pool the standardized mean differences or odds ratios and corresponding 95% confidence intervals. Heterogeneity was assessed using the I² value.

RESULTS

A total of 514 pregnancies with twin-to-twin transfusion syndrome managed with fetoscopic laser photocoagulation were included in the final analysis. Following the logistic regression, factors that remained significant for donor demise were selective fetal growth restriction (odds ratio, 1.9; 95% confidence interval, 1.3-2.8; P=.001) and umbilical artery blood flow with absent or reversed end-diastolic velocity of the donor (odds ratio, 2.06; 95% confidence interval, 1.2-3.4; P=.004). A significant factor associated with recipient demise was absent or reversed a-wave in the ductus venosus of the recipient (odds ratio, 1.74; 95% confidence interval, 1.07-3.13; P=.04). Data from 23 studies and our current cohort were included. A total of 4892 pregnancies with twin-to-twin transfusion syndrome managed with fetoscopic laser photocoagulation were analyzed for risk factors for donor demise, and 4594 pregnancies with twin-to-twin transfusion syndrome were analyzed for recipient demise. Among studies, the overall incidence rates ranged from 10.9% to 35.8% for donor demise and 7.3% to 24.5% for recipient demise. Significant risk factors for donor demise were intertwin estimated fetal weight discordance of >25% (odds ratio, 1.86; 95% confidence interval, 1.44-2.4; I², 0.0%), selective fetal growth restriction (odds ratio, 1.78; 95% confidence interval, 1.4-2.27; I², 0.0%), twin-to-twin transfusion syndrome stage III (odds ratio, 2.18; 95% confidence interval, 1.53-3.12; I², 0.0%), umbilical artery blood flow with absent or reversed end-diastolic velocity of the donor (odds ratio, 2.31; 95% confidence interval, 1.9-2.8; I², 23.7%), absent or reversed a-wave in the ductus venosus of the donor (odds ratio, 1.83; 95% confidence interval, 1.45-2.3; I², 0.0%), and presence of arterioarterial anastomoses (odds ratio, 2.81; 95% confidence interval, 1.35-5.85; I², 90.7%). Sequential selective coagulation was protective against donor demise (odds ratio, 0.31; 95% confidence interval, 0.16-0.58; I², 0.0%). Significant risk factors for recipient demise were twin-to-twin transfusion syndrome stage IV (odds ratio, 2.18; 95% confidence interval, 1.01-4.6; I², 16.5%), umbilical artery blood flow with absent or reversed end-diastolic velocity of the recipient (odds ratio, 2.68; 95% confidence interval, 1.91-3.74; I², 0.0%), absent or reversed a-wave in the ductus venosus of the recipient (odds ratio, 2.37; 95% confidence interval, 1.55-3.64; I², 60.2%), and middle cerebral artery peak systolic velocity of >1.5 multiple of the median (odds ratio, 3.06; 95% confidence interval, 1.36-6.88; I², 0.0%).

CONCLUSION

Abnormal blood flow patterns represented by abnormal Doppler studies and low fetal weight were associated with single fetal demise in women with twin-to-twin transfusion syndrome undergoing laser therapy. Although sequential selective coagulation was protective against donor demise, the presence of arterioarterial anastomoses was considerably associated with donor demise. This meta-analysis extensively investigated the association of a wide range of preoperative and operative factors with fetal demise. These findings may be important inpatient counseling, in further understanding the disease, and perhaps in improving surgical techniques.

Impact of Preoperative Cervical Length on Pregnancy Outcome in Twin-Twin Transfusion Syndrome

OBJECTIVE

To evaluate the impact of preoperative cervical length on pregnancy outcome in monochorionic diamniotic twin pregnancies complicated by twin-twin transfusion syndrome that underwent laser surgery or cord occlusion.

MATERIALS AND METHODS

Retrospective study of 330 patients stratified by preoperative cervical length (≥25 mm, 16-24 mm,≤15 mm). Maternal characteristics, operative data, and pregnancy outcomes were compared between the cervical length groups as well as between the subgroups of patients with a cervical length≤15 mm according to management (expectant vs. cerclage).

RESULTS

A preoperative cervical length≥25 mm was observed in 82% (n=271) of cases, 16-24 mm in 9% (n=29), and≤15 mm in 9% (n=30). Patients with a preoperative cervical length≤15 mm showed shorter median procedure-to-delivery interval (5.5 weeks vs. 11.6 (16-24 mm) vs. 13.0 (≥25 mm); p<0.001); lower median gestational age at delivery (29.5 weeks vs. 34.3 (16-24 mm) vs. 33.4 (≥25 mm); p<0.001); higher rate of preterm delivery<32 weeks (78 vs. 20% (16-24 mm) vs. 31% (≥25 mm); p<0.001); and lower neonatal survival rate of at least one twin (70 vs. 88% (16-24 mm) vs. 93% (≥25 mm); p<0.001). Outcome of patients with a preoperative cervical length≤15 mm was similar regardless of management.

CONCLUSION

Monochorionic diamniotic twin pregnancies complicated by twin-twin transfusion syndrome with a preoperative cervical length≤15 mm showed a higher rate of preterm delivery<32 weeks and lower neonatal survival. The role of a cervical cerclage remains unclear.

Gestational age and Quintero staging as predictors of single fetal demise in twin-twin transfusion syndrome after fetoscopic laser photocoagulation: a systematic review and meta-analysis

BACKGROUND

Single fetal demise after intervention for twin-twin transfusion syndrome is a relatively common complication and is often devastating for the patients.

OBJECTIVE

This meta-analysis aimed to evaluate the risk of single fetal demise based on gestational age and Quintero staging at the time of interventions in twin-to-twin transfusion syndrome after fetoscopic laser photocoagulation.

STUDY DESIGN

Systematic search was performed in PubMed, Web of Science, and Scopus from inception to August 2021. The primary outcome was to compare the incidence of fetal demise between low (I and II) and high (III and IV) twin-to-twin transfusion syndrome Quintero stages. The rate of donor and recipient fetal demise in each stage was compared with that in stage I. Gestational age at fetoscopic laser photocoagulation was compared between surviving fetuses and fetuses that died.

RESULTS

A total of 10 studies (4031 fetuses with twin-to-twin transfusion syndrome) were included in this review. Donor demise was associated with high Quintero stages compared with surviving donors (odds ratio, 2.42; 95% confidence interval, 1.78–3.29; P<.001; I², 0%). Recipient fetal demise had a trend for higher Quintero stage compared with surviving recipients, but the analysis did not achieve statistical significance. Pregnancies with donor demise had lower gestational at the time of fetoscopic laser photocoagulation (mean difference, −0.56; 95% confidence interval, –0.93 to –0.18; P=.003; I², 36%), whereas pregnancies complicated by recipient demise had similar gestational at time of fetoscopic laser photocoagulation compared with those without demise.

CONCLUSION

Demise of the donor fetus was significantly increased after fetoscopic laser photocoagulation for higher stages compared with lower ones. Lower gestational age at the time of fetoscopic laser photocoagulation was associated with an increased risk of single fetal demise in twin-to-twin transfusion syndrome. This was attributed to increased donor demise but not recipient death.

Fetal Cardiac Function: Myocardial Performance Index

The Myocardial Performance Index (MPI) or Tei index, presented by Tei in 1995, is the ratio of the sum of the duration of the isovolumetric contraction time (ICT) and isovolumetric relaxation time (IRT) to the duration of the ejection time (ET). The Modified Myocardial Performance Index (Mod-MPI), proposed in 2005, is considered a reliable and useful tool in the study of fetal heart function in several conditions, such as growth restriction, twin-twin transfusion syndrome, maternal diabetes, preeclampsia, intrahepatic cholestasis of pregnancy, and adverse perinatal outcomes. Nevertheless, clinical translation is currently limited by poorly standardised methodology as variations in the technique, machine settings, caliper placement, and specific training required can result in significantly different MPI values. This review aims to provide a survey of the relevant literature on MPI, present a strict methodology and technical considerations, and propose future research.

Dual demise following laser surgery for twin-twin transfusion syndrome: Analysis of 52 cases at a single fetal surgery center

OBJECTIVE

To evaluate all individual cases of dual twin demise following laser surgery for twin-twin transfusion syndrome (TTTS).

METHOD

This is an analysis of all monochorionic diamniotic twin gestations with TTTS complicated by dual demise following laser surgery from 2006 to 2019. Cases were reviewed by (1) a fetal surgeon researcher and (2) a panel of independent experienced maternal-fetal medicine specialists to code an etiology of demise for the donor and recipient, and to assess for possible preventability.

RESULTS

Of 753 twins that underwent laser surgery for TTTS, 52 (6.9%) had postoperative dual demise. In this subgroup, gestational age at surgery was 19.5 (16.1-24.9) weeks, and 36 (69.2%) patients were Quintero stage III and IV. The most common etiology was the spectrum of disorders leading to preterm delivery, which included cervical insufficiency, preterm premature rupture of membranes, and preterm labor (44.2% and 48.1%, donor and recipient, respectively). Some degree of preventability was estimated for 23.1% of dual demises.

CONCLUSIONS

The most common cause of dual demise post laser surgery for TTTS was preterm birth, reinforcing the need for studies regarding the etiology and prevention of post-fetoscopy prematurity. Nearly one-quarter of dual demise cases were deemed potentially preventable.

Re-evaluation of the predictive value of Quintero staging of twin-twin transfusion syndrome for fetal death after fetoscopic laser photocoagulation

OBJECTIVE

To elucidate the significance of sonographic indices, including Doppler waveforms, that constitute the Quintero classification for predicting death of the recipient or donor after fetoscopic laser photocoagulation (FLP) for twin-twin transfusion syndrome (TTTS).

METHODS

Prospectively collected data of twins who underwent FLP for TTTS were reviewed. Among the abnormal indices of ultrasound performed just before FLP, factors that were significantly associated with fetal and neonatal deaths in the log-rank test, including fetal demise of co-twins and preterm birth before 28 weeks of gestation, were introduced into the Cox proportional-hazards model to calculate risk ratio (RR).

RESULTS

We included 235 cases with a prevalence of recipient and donor deaths of 7% and 14%, respectively. In the proportional-hazards model, absent or reversed umbilical artery end-diastolic velocity (UA AREDV) of recipients (n = 7) was independently associated with recipient death (RR = 6.97). In recipients without UA AREDV, reversed ductus venosus (DV) a-wave of recipients (RR = 3.55) was independently associated with recipient death. In donors, UA AREDV with a visible bladder (stage III atypical donor) was independently associated with donor death (RR = 4.24).

CONCLUSION

Some individual components of the Quintero stage are associated with death of either recipient or donor twins following FLP.

Perinatal outcomes and factors affecting the survival rate of fetuses with twin-to-twin transfusion syndrome treated with fetoscopic laser coagulation: a single-center seven-year experience

OBJECTIVES

This single-center study aimed to assess the perinatal outcomes and its associated factors in fetuses with twin-to-twin transfusion syndrome (TTTS) treated by fetoscopic laser coagulation (FLC).

METHODS

In this retrospective study, we included fetuses prenatally diagnosed with TTTS at Asan Medical Center, Seoul, Korea, between October 2011 and December 2018. All patients with TTTS stage II or higher and those with stage I TTTS coupled with symptomatic polyhydramnios or cardiac dysfunction were eligible for FLC.

RESULTS

A total of 172 cases of monochorionic diamniotic twins and one case of dichorionic triamniotic triplets were prenatally diagnosed with TTTS and treated with FLC. The median gestational ages (GAs) at diagnosis and FLC were 20.3 and 20.5 weeks, respectively. The median GA of survivors at delivery was 32.5 weeks. The overall at least one twin- and double-survival rates within 28 days after birth were 82.1% and 55.5%, respectively. The GAs at diagnosis and FLC, Quintero stage, inter-twin weight discordance, associated selective intrauterine growth restriction (sIUGR), procedure time, volume of amnioreduction, preterm prelabor rupture of membranes (PPROM) within one week after FLC, intraoperative intrauterine bleeding, and chorioamnionitis were significant predictive factors of perinatal death. Associated sIUGR, absent end-diastolic flow of umbilical artery, and abnormal cord insertion were significantly associated with donor demise in utero, whereas lower GA at diagnosis and FLC, smaller twins at FLC, pulsatile umbilical vein, and presence of mitral regurgitation were significantly associated with recipient demise in utero. Since the application of the Solomon technique, the survival rate has improved from 75.4% to 88.8%. The FLC before 17 weeks was associated with PPROM within one week after FLC and lower survival rate, whereas that after 24 weeks was associated with twin anemia-polycythemia sequence and higher survival rate. We reached a survival rate of 82% for at least one survival with only 12 procedures.

CONCLUSIONS

FLC is an effective treatment for TTTS. The learning curve reached the acceptable target faster than in previous studies. Several prenatal parameters are identified as predictive factors of fetal survival in TTTS treated with FLC.

Percent Absent End-Diastolic Velocity in the Umbilical Artery and Donor Twin Demise after Laser Surgery for Twin-Twin Transfusion Syndrome

INTRODUCTION

To examine the association of preoperative absent end-diastolic velocity (AEDV) and percent AEDV (%AEDV) in the umbilical artery (UA) with donor twin intrauterine fetal demise (IUFD) after laser surgery for twin-twin transfusion syndrome (TTTS).

METHODS

We performed a retrospective study of stage III/IV TTTS patients who underwent laser surgery from 2006 to 2016. Donors were classified as having preoperative persistent AEDV (yes/no). %AEDV was calculated for those with AEDV as 100× the proportion of the total cardiac cycle in AEDV. Using multiple logistic regression, we tested for an association between the outcome donor IUFD and AEDV risk factors (part 1) and %AEDV (part 2). We stratified these analyses by estimated fetal weight (EFW) discordance ≥20 versus <20%.

RESULTS

Of 344 cases, 153 (44.5%) donors had AEDV. Part 1 did not confirm an independent association between AEDV and donor IUFD. In the part 2 analysis of the 153 patients with AEDV, %AEDV was a positive risk factor for donor IUFD only in those with discordance (n = 129) (OR 1.04, 95% CI 1.01-1.08, p = 0.0278) when adjusting for %EFW discordance, presence of arterioarterial anastomoses, and multiparity.

DISCUSSION

Among stage III/IV TTTS patients with AEDV, %AEDV was a risk factor for donor IUFD only in the presence of EFW discordance.

The value of echocardiography and Doppler in the prediction of fetal demise after laser coagulation for TTTS: A systematic review and meta-analysis

This study aimed to investigate the value of echocardiography and Doppler before fetoscopic laser coagulation for twin‐twin transfusion syndrome (TTTS) in the prediction of intrauterine fetal demise (IUFD). We performed a systematic review and meta‐analysis to compare preoperative parameters between fetuses with and without demise after laser surgery. Eighteen studies were included. Recipient twins have an increased risk of demise in case of preoperative absent/reversed flow (A/REDF) in the umbilical artery (odds ratio [OR] 2.76, 95% confidence interval [CI], 1.78‐4.28), absent or reversed a‐wave in the ductus venosus (OR 2.32, 95% CI, 1.70‐3.16), or a middle cerebral artery peak systolic velocity > 1.5 multiples of the median (MoM) (OR 7.59, 95% CI, 2.56‐22.46). In donors, only A/REDF in the umbilical artery (OR 3.40, 95% CI, 2.68‐4.32) and absent or reversed a‐wave in the ductus venosus (OR 1.66, 95% CI, 1.12‐2.47) were associated with IUFD. No association was found between donor‐IUFD and preoperative myocardial performance index (MPI). Two studies found an association between abnormal MPI and recipient demise. With this study, we have identified a set of preoperative Doppler parameters predictive of fetal demise after laser surgery. More research is needed to assess the utility of preoperative echocardiographic parameters such as the MPI in predicting IUFD.

What's already known about this topic?

Doppler parameters are associated with fetal demise after laser surgery.

Echocardiographic parameters are currently not used in risk stratification.

What does this study add?

A more extensive set of preoperative Doppler parameters is defined to predict post‐laser fetal demise.

The utility of preoperative echocardiographic parameters such as the MPI in predicting fetal demise remains unclear.

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.

Factors associated to early intrauterine fetal demise after laser for TTTS by preoperative fetal heart and Doppler ultrasound

OBJECTIVE

To determine the prognostic value of fetal Doppler and echocardiographic parameters for intrauterine fetal demise (IUFD) within 24 hours and within 1 week after laser coagulation in monochorionic pregnancies complicated by twin-twin transfusion syndrome.

METHOD

This retrospective study correlated the preoperative hemodynamic and echocardiography parameters to the outcome in fetuses with twin-twin transfusion syndrome undergoing laser therapy.

RESULTS

One hundred and twelve laser coagulations were performed between February 2006 and June 2015. The total (single and double) IUFD rate was 27.7%. Further, 59% of IUFD occurred within 24 hours and 74.4% occurred within 1 week after laser. The following were associated to IUFD within 24 hours: the middle cerebral arterial pulsatility index in the donor, abnormal umbilical artery (UA) end diastolic flow, increased middle cerebral artery peak systolic velocity, and right ventricular myocardial performance index (RV-MPI) z-score in the recipient. For IUFD within 1 week were the pulsatility index in the donor UA and the recipient abnormalities in UA, ductus venosus, middle cerebral artery-peak systolic velocity, and RV-MPI z-score.

CONCLUSION

Following laser was early IUFD that was associated with Doppler findings suggesting donor cerebroplacental redistribution, and recipient overload cardiomyopathy, such as abnormal ductus venosus and UA Dopplers as well as an increase of RV-MPI.

Impact of recipient twin preoperative myocardial performance index in twin-twin transfusion syndrome treated with laser. J Matern Fetal Neonatal Med 2016;30:767-771. [PMID: 27150066 DOI: 10.1080/14767058.2016.1187124]

OBJECTIVE

To validate the efficacy of laser therapy for twin-twin transfusion syndrome (TTTS) in the treatment of recipient twin cardiomyopathy and investigate whether severity of preoperative cardiomyopathy can predict fetal survival postoperatively.

STUDY DESIGN

Retrospective study of monochorionic-diamniotic (MCDA) pregnancies complicated by TTTS treated by selective fetoscopic laser photocoagulation (SFLP) performed between March 2010 and October 2014 at a single center. The recipient right ventricular (RV) and left ventricular (LV) myocardial performance index (MPI) were measured both pre- and postoperatively. The data were analyzed with the Wilcoxon signed rank and parametric t-tests.

RESULTS

Forty-three women met inclusion criteria during the study period. There was a substantial improvement in recipient LV (0.57 ± 0.13 versus 0.43 ± 0.13, p ≤ 0.0001) and RV (0.60 ± 0.16 versus 0.49 ± 0.18, p ≤ 0.0001) MPI postoperatively (median = 8 days). Recipient preoperative LV and RV MPI did not correlate with recipient or donor survival at 24 hours, 7 days or at birth. Thirty-seven recipients (95%) showed improvement in either LV or RV MPI and 22 (56%) showed complete resolution of cardiac dysfunction.

CONCLUSION

Laser treatment for TTTS causes rapid improvement in the cardiac function of recipient fetuses. The severity of recipient preoperative MPI does not correlate with survival of either twin postoperatively.

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.

Chorioamniotic membrane separation after fetoscopy in monochorionic twin pregnancy: incidence and impact on perinatal outcome

OBJECTIVE

To evaluate the incidence of chorioamniotic membrane separation (CMS) after fetoscopy in monochorionic diamniotic (MCDA) twins and its impact on pregnancy outcome.

METHODS

The study group comprised a consecutive series of 338 women with an MCDA pregnancy complicated by twin-twin transfusion syndrome (TTTS) or selective intrauterine growth restriction (sIUGR) treated with selective laser photocoagulation of communicating vessels (SLPCV) or cord occlusion (CO). Data obtained included cervical length, gestational age at procedure, type and duration of surgery and placental location. The incidence of CMS, the rates of miscarriage and preterm prelabor rupture of membranes (PPROM), gestational age at delivery and neonatal survival were recorded.

RESULTS

Of the study population of MCDA pregnancies, 270 (79.9%) had TTTS and 68 (20.1%) had sIUGR. SLPCV was performed in 252 (74.6%) cases and CO in 86 (25.4%). Postoperative CMS was observed in 70 (20.7%) cases. Patients with CMS had higher rates of miscarriage (14.3% vs 7.1%; P = 0.049), PPROM before 32 weeks (43.3% vs 13.7%; P < 0.001) and preterm delivery before 32 weeks (53.3% vs 26.1%; P < 0.001) and a lower rate of neonatal survival of at least one twin (81.7% vs 93.6%; P = 0.003). Multivariate analysis showed that gestational age at surgery was the only independent predictor, with the highest proportion of CMS occurring in cases that underwent surgery before 18 weeks' gestation (odds ratio, 2.941 (95% CI, 1.640-5.275); P < 0.001). There was no influence of cervical length, placental location, duration of surgery or type of surgery on the risk of CMS.

CONCLUSIONS

CMS complicated one-fifth of all MCDA pregnancies that underwent fetoscopy. It appeared to be more common in those who underwent surgery before 18 weeks' gestation and was associated with poorer outcomes. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

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.

Abnormal umbilical artery Doppler findings in the recipient twin before laser surgery for twin-twin transfusion syndrome

OBJECTIVES

In twin-twin transfusion syndrome (TTTS), persistent absent or reversed end-diastolic flow in the umbilical artery is a rare finding in the recipient twin, and the clinical implications of this finding are not well characterized. We sought to study the clinical importance of abnormal umbilical artery Doppler waveforms in recipient twins and determine the perinatal survival of these twins after laser surgery.

METHODS

A retrospective study of patients with TTTS treated with laser surgery between 2006 and 2012 was conducted. Recipient twins with absent or reversed umbilical artery end-diastolic flow on preoperative sonography were identified, and clinical and perinatal outcomes were compared to the remaining cohort. Statistical analyses were performed with Fisher exact and χ(2) tests.

RESULTS

Of 369 consecutive TTTS cases, 14 (3.8%) had absent or reversed umbilical artery end-diastolic flow in the recipient twin. The rate of hydrops was higher in this group compared to those without absent or reversed flow (35.7% [5 of 14] versus 10.1% [36 of 355]; P = .0125). The rate of recipient twin growth restriction was also higher in the absent or reversed flow group (28.6% [4 of 14] versus 3.9% [14 of 355]; P = .0029). There was an increased rate of recipient fetal demise within 24 hours after surgery in those with absent or reversed flow (21.4% [3 of 14] versus 2.5% [9 of 355]; P = .0078), although there was no statistical difference in 30-day survival between the groups (78.6% [11 of 14] versus 89.9% [319 of 355]; P = .1751).

CONCLUSIONS

Doppler findings of absent or reversed umbilical artery end-diastolic flow are rare in recipient twins. Although immediate post-laser surgery survival is relatively decreased in this group, overall perinatal survival rates appear to be favorable.

Pre-Operative Twin Anemia/Polycythemia in the Setting of Twin-Twin Transfusion Syndrome (TTTS)

Introduction: Twin-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS) are classified as distinct clinical disorders associated with unbalanced blood flow through placental vascular communications. Typically, TAPS placentas demonstrate few <1 mm arteriovenous (AV) communications, and at fetoscopy the twins are visibly pale and plethoric. Materials and Methods: In a cohort of TTTS patients who underwent laser surgery, those with preoperative findings suggestive of anemia/polycythemia (AP) were compared to those with TTTS alone. AP was defined as middle cerebral artery peak systolic velocity in one twin >1.5 multiples of the median (MoM), and <1.0 MoM in the other. Results: Of 369 TTTS patients, 9 (2.4%) met criteria for preoperative AP. The mean number (±SD) of AV communications in the TTTS + AP group was 5.6 ± 5.7, compared with 8.8 ± 4.8 in the TTTS-alone group (p = 0.013). Five TTTS + AP patients (56%) had a few thin AV communications (mean 2.8 ± 1.6); all 5 had visibly pale and plethoric twins. The remaining 4 (44%) had large or numerous anastomoses (mean 10.5 ± 6.8); none had fetal skin color discordance. Discussion: Preoperative AP affected 2% of TTTS patients. Of these, approximately half had placental and skin color findings typically reported with isolated TAPS.