Validation of Quintero stage III sub-classification for twin-twin transfusion syndrome based on visibility of donor bladder: characteristic differences in pathophysiology and prognosis

Effect of Superficial Anastomoses on Circulatory Dynamics in Twin-Twin Transfusion Syndrome

The role of superficial anastomoses in the survival of fetuses with twin-twin transfusion syndrome after fetoscopic laser photocoagulation is unknown. This study aimed to evaluate how superficial anastomoses affect the circulatory dynamics of both fetuses with twin-twin transfusion syndrome using ductus venous Doppler waveforms. We included all twin-twin transfusion syndrome (TTTS) patients who underwent fetoscopic laser photocoagulation in our institution from 2006 to 2019; fetal demise cases after fetoscopic laser photocoagulation were excluded. We recorded ductus venous Doppler waveforms on the same day or one day before fetoscopic laser photocoagulation and one day after fetoscopic laser photocoagulation and measured the ductus venous pulsatility index and velocity ratios. We compared these z-scores of donor and recipient twins between a group without superficial anastomoses and the groups with arterio-arterial or veno-venous anastomoses. A total of 115 surviving TTTS placentas after fetoscopic laser photocoagulation were analyzed. The ductus venous pulsatility index and all ratios were better in recipient twins with arterio-arterial anastomoses than in those without. The a-wave-related ratios were better in recipient twins with veno-venous anastomoses than in those without. Superficial anastomoses reduced the blood volume and arterio-arterial anastomoses protected the diastolic cardiac function in recipient twin-twin transfusion syndrome twins before fetoscopic laser photocoagulation. Superficial anastomoses in TTTS equilibrate blood pressure between donor and recipient twins.

What fetal medicine specialists should know about the monochorionic placenta

Monochorionic twins are at risk of transfusion imbalances as long as they are connected to the shared placenta during their intrauterine journey. This review article addresses the macroscopic examination of the monochorionic placenta at the time of birth and explains placental dye injection studies to document the vascular anastomoses and placental sharing. We elaborate on the different types of anastomoses, the importance of how the placenta is divided between the twins, and the angioarchitecture in twin-twin transfusion syndrome, twin anemia polycythemia sequence and selective fetal growth restriction.

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.

Outcomes of fetoscopic laser surgery for twin-to-twin transfusion syndrome between 26 and 27 weeks of gestation in Japan

AIM

The purpose of this study was to investigate the outcomes of fetoscopic laser photocoagulation (FLP) for twin-to-twin transfusion syndrome (TTTS) in Japan.

METHODS

The retrospective cohort study (2012-2018) was conducted in monochorionic twin pregnancies that underwent FLP for TTTS between 26 and 27 weeks from 2012 to 2018. The perioperative data, maternal complications, gestational age (GA) at delivery, neonatal complications, and survival of infants at 28 days of age were analyzed. At term-equivalent age, severe neurological complications were identified by imaging study.

RESULTS

Of 644 patients, 28 (4.3%) underwent FLP between 26 and 27 weeks, and 26 were analyzed. FLP procedures were technically successful in all cases. There were no cases of major maternal complications after surgery. Preterm rupture of membranes occurred in 34.6% of cases, and the mean GA at delivery was 33.2 ± 3.1 weeks. The survival of both twins was found in 23 (88.4%) cases, and the perinatal survival rate of at least one twin at 28 days of age was 100%. Severe neurological complications were found in six (12.2%) cases out of 49.

CONCLUSIONS

FLP for TTTS between 26 and 27 weeks provided a good prognosis and caused no major maternal complications. However, severe neurological findings were found in 12% of infants.

The roles of superficial anastomoses in twin-twin transfusion syndrome

OBJECTIVE

We aimed to evaluate whether types of vascular anastomoses affect fetal demise (FD) in twin-twin transfusion syndrome (TTTS) after fetoscopic laser photocoagulation (FLP).

METHODS

All TTTS patients who underwent FLP in our institution from 2005 to 2017 were included. We described vascular anastomoses during FLP as either arterio-arterial (AA), veno-venous (VV), or arterial-venous (AV), and abnormal fetal Doppler waveforms before FLP. We also analyzed risk factors for FD following FLP.

RESULTS

In total, 184 TTTS placentas following FLP were analyzed (36 cases of donor-only FD, 12 cases of recipient-only FD, 3 cases of double FD, and 133 cases of both alive). AA anastomoses prevalence, absent or reverse end-diastolic velocity of umbilical artery (UAAREDV) of donor before FLP, gestational age at the time of FLP and operation time of FLP were independent risk factors for donor FD. VV anastomoses prevalence and UAAREDV of recipient before FLP were independent risk factors for recipient FD. VV anastomoses prevalence was higher in double FD cases than in FD of one twin or both alive (p = 0.002). AV anastomoses number and number of cases with more AV anastomoses from donor to recipient were not significantly different between FD and non-FD cases.

DISCUSSION

AA anastomoses are associated FD of the donor following FLP and may protect the donor from hypovolemia before FLP. VV anastomoses are detected more frequently in FD of the recipient and double FD placentas following FLP and may rescue hypervolemia of the recipient or circulations of both fetuses before FLP.

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.

Fetoscopic laser photocoagulation for twin-twin transfusion syndrome

The aim of this study was to review fetoscopic laser photocoagulation (FLP), which ablates placental vascular anastomoses to treat twin–twin transfusion syndrome (TTTS). A review of studies reporting on the procedures, outcomes, complications and nonconventional applications of FLP for TTTS was conducted. FLP has been established as the primary treatment for monochorionic twin pregnancy associated with TTTS at 16–26 weeks. FLP is the only therapy that directly addresses the underlying pathophysiology. The recent technique modification of FLP, referred to as the ‘Solomon technique’, induces selective coagulation to connect the anastomoses ablation sites and has been introduced to reduce residual anastomoses. The perinatal survival following FLP improved significantly with advances in the technique after its introduction. The recent survival rates of both twins and at least one twin are 70% and more than 90%, respectively. However, there is still an 11–14% risk of long‐term neurodevelopment impairment. The premature rupture of membranes that leads to preterm labor is a common complication after FLP. FLP is a valuable treatment option for feto‐fetal transfusion syndrome in triplets and for TTTS after 26 weeks. FLP for selective intrauterine growth restriction may be potentially beneficial when accompanied by abnormal Doppler findings and oligohydramnios. FLP is the optimal treatment option for TTTS at 16–26 weeks of gestation. FLP appears to be applicable in triplets, TTTS after 26 weeks and cases of selective intrauterine growth restriction with abnormal Doppler findings and oligohydramnios. FLP is the most common and successful fetal intervention. Improvement in the neurodevelopmental outcomes after FLP is a future focus.

Atypical twin-to-twin transfusion syndrome: prevalence in a population undergoing fetoscopic laser ablation of communicating placental vessels

BACKGROUND

The diagnosis of twin-to-twin transfusion syndrome (TTTS) usually relies the presence of polyhydramnios in one sac with concomitant oligohydramnios in the other sac in a monochorionic diamniotic twin pregnancy. However, TTTS does not always show a linear progression and may present with cardiac compromise or critically abnormal Doppler velocimetry in either fetus before fluid measurements meet the typically used cutoff.

OBJECTIVE

The aim of this study was to investigate the prevalence of atypical presentations of TTTS in a population undergoing laser fetoscopy.

STUDY DESIGN

We performed a retrospective review of our database of TTTS laser fetoscopy from 2003 to the present. Our center is the regional referral center in the Pacific Northwest for minimally invasive treatment of complicated monochorionic twin pregnancies. Cases were labeled as "atypical" if fluid discordance did not meet formal TTTS criteria (oligohydramnios defined as maximum vertical pocket [MVP] <2 and polyhydramnios defined as MVP >8 before 20 weeks and >10 after 20 weeks). The rationale for consideration of laser fetoscopy was other evidence of severe TTTS such as significant cardiac compromise, evidence of twin anemia polycythemia sequence (TAPS), or persistent critically abnormal cord Dopplers.

RESULTS

Three hundred seventy-nine cases of fetoscopic laser ablation for TTTS and its variants were available for review. Sixteen cases were excluded for a triplet pregnancy, 4 due to septostomy prior to referral to our center, 3 for monoamniotic pregnancy, and 11 for previous laser fetoscopy. Three hundred forty-five cases remained for evaluation. Among these, 25 cases were identified as "atypical," equaling 7.24% of our population. Eleven of these were for stage 3 recipient disease, 3 were for stage 4 recipient disease, 4 were for stage 3 both in recipient and donor, 4 were for stage 3 donor disease, and 3 were for spontaneous TAPS.

CONCLUSION

In TTTS, severity of fetal compromise does not consistently correlate with fluid abnormalities meeting established criteria. This may be especially true in rapidly progressing cases. Attempts at rigid diagnostic amniotic fluid criteria may underestimate the severity and incidence of TTTS. This underscores the importance of careful surveillance, including arterial and venous Doppler velocimetry, of all monochorionic pregnancies.

Twin-Twin Transfusion Syndrome in Cases with Suspected Close Proximity of Umbilical Cord Insertions

We encountered 3 cases of twin-twin transfusion syndrome (TTTS), in which preoperative ultrasonography revealed that the cord insertion sites of the twins were close. Two cases were successfully treated with fetoscopic laser photocoagulation (FLP); however, the third case could not be treated surgically because fetoscopy revealed that the cord insertions formed a V-shaped joint above the placenta and that all chorionic vessels of the placental surface were shared by the twins. No residual anastomoses were detected on placental examination in the 2 cases treated with FLP. Our experiences indicate that the feasibility of FLP could be evaluated using fetoscopy, not just ultrasonography, in cases of TTTS accompanied by proximate umbilical cord insertion.

Laser therapy for twin-twin transfusion syndrome in the absence of fetoscopically visible placental vascular anastomoses

Fetoscopic laser photocoagulation (FLP) was performed at 22 weeks of gestation for a pregnancy complicated with twin-twin transfusion syndrome (TTTS) and an anterior placenta. However, vascular anastomoses could not be identified by the fetoscope. To dichotomize the circulation between the twins, the terminal ends of the paired artery and vein of the recipient twin were coagulated. In addition, a line was drawn with the laser connecting the dots, which had been coagulated. The Doppler waveform as well as the amniotic fluid volume of each twin normalized after the procedure. The twins were delivered by cesarean section subsequent to onset of labor at gestational week 30; the recipient twin weighed 1,350 g and the donor twin weighed 550 g. Both twins had a normal neurologic exam at 6 months of age. Patent placental vascular anastomoses could not be detected. This case demonstrates that vascular anastomoses in TTTS may not be identified by a fetoscope and that FLP to coagulate the entire vascular equator closer to the area of the recipient twin was effective in this rare situation.

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.

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.